ＡＤＳＬ技術開示資料

第３版

平成１６年２月
西日本電信電話株式会社
本資料の内容は、機能追加などにより追加・変更されることがあります。
なお、内容についての問い合わせは、下記宛にお願い致します。
西 日 本 電 信 電 話 株 式 会 社
ブ ロ ー ド バ ン ド 推 進 本 部
ＢＢアクセスサービス部サービス開発グループ
adsl-tech@ml.hq.west.ntt.co.jp

-1-

まえがき
このADSL技術開示資料は、西日本電信電話株式会社（以下、NTT西日本）と接続する端末機器のインタフェース条件について説明したもので、端末機器等を設計、準備する際の参考となる技術的情報を提供するものです。既にサービス提供中の情報については、技術参考資料（フレッツ・シリーズ）を参照して下さい。技術参考資料は、ホームページ（http://www.ntt-west.co.jp）及び情報ステーショ
ンにて閲覧できます。
本資料は、ITU-T勧告G.992.1の本文と合わせて参考いただく情報とさせていただきます。ITU-T等で標準化作業中の方式を含みますが、標準化された後は標準化技術として置き換わります。
また、本資料は、NTT西日本のサービス提供を保証するものではありません。
接続される端末設備が必ず適合しなければならない技術的条件は、「端末設備等の接続の技術的条件」又は「端末設備等規則」（昭和60年郵政省令31号）に定められています。
今後、本資料は、インタフェースの追加・変更にあわせて予告なく変更される場合があります。

-2-

改版履歴
版数

年月

主な内容

第１版

2003年8月

・下り伝送速度の高速化（周波数帯域：138kHz〜3.75MHz）

2003年11月

・下り伝送速度の高速化（周波数帯域：25kHz〜3.75MHz）・上り伝送速度の高速化（周波数帯域：25kHz〜276kHz）

2004年2月

・上り伝送速度の高速化（周波数帯域：25kHz〜483kHz）
・長延化

第２版

第３版

-3-

使用帯域

資料番号
（ページ）
１
（P5〜P62）２（P63〜P128）
３（P129〜P197）
４（P198〜P266）
５（P267〜P332）
６（P333〜P401）

サービス提供上り信号

下り信号

シェーピング

138k〜3.75MHz

25k〜138kHz

なし

モア４０

25k〜3.75MHz

25k〜276kHz

なし−

25k〜3.75MHz

25k〜414kHzあり−

25k〜3.75MHz

25k〜483kHz

なし−

25k〜2.2MHｚ

25k〜276KHz

なし−

25ｋ〜2.2MHｚ

25k〜414kHzあり−

25k〜276kHz

なし

−

７

25ｋ〜1.1MHｚ（P402〜P464）（長延化方式を含む）

-4-

資料１
G.992.1 ANNEX Q
PROPRIETARY EXTENSION TO G.992.1 ANNEX I

Attached is proposed text for G.992.1 Annex Q (Quad spectrum), a proprietary extension to G.992.1 Annex I to extend
the data rate beyond 32 Mbit/s on short loops by way of:• Increased bandwidth Æ increased number of subcarriers, NSC=1024 (used subcarriers up to 869)
• Increased bit loading, beyond 15 bits/bin• Extended framing Æ S=1/2n, with support for n = 1 to 4
The attached text is the approved draft text for Annex I, marked up with revision control to show the changes necessary
to support the additional functionality. Editorial changes such as replacing “Annex I” with “Annex Q” are not shownwith revision control.

-5-ANNEX Q
Specific requirements for an ADSL system to support data rates greater than 32 Mbit/s on short loops operatingin the same cable as ISDN as defined in ITU-T Recommendation G.961 Appendix III

Q.1

Scope

This annex describes those specifications that are unique to an ADSL system coexisting in the same binder as
TCM-ISDN as defined Recommendation G.961 Appendix III. The subclauses in this annex provide supplementary andreplacement material to the clauses in the main body. The nature of the material is parenthetically indicated in the
subclause heading. The modifications described in this annex allow a performance improvement from the ADSL system
specified in Annex C for short loops in an environment coexisting with TCM-ISDN in the same cable. Specifically, thisAnnex specifies extensions to downstream bandwidth, framing modes, and maximum bit loading to support
downstream data rates greater than 32 Mbit/s. This annex also defines those parameters of this ADSL system that havebeen left undefined in the main body of this Recommendation. It is recommended that ADSL system implementing
Annex Q also implements Annex C.
Q.2

Definitions

Bitmap-FC
Bitmap-FR
Bitmap-NC
Bitmap-NR
Dual Bitmap
FEXT Bitmap
FEXTC duration
FEXTC symbol
FEXTR duration
FEXTR symbol
Hyperframe
NEXTC duration
NEXTC symbol
NEXTR duration
NEXTR symbol
NSC

NSWF
Subframe
TTR
TTRC
TTRR
UI

ATU-R transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-R
ATU-R transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-R
The Dual Bitmap method has dual bit rates under the FEXT and NEXT noise from TCM-ISDN
Similar to the Dual Bitmap method however transmission only occurs during FEXT noise fromTCM-ISDN
TCM-ISDN FEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN FEXTTCM-ISDN FEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN FEXT
5 Superframes structure which synchronized TTR
TCM-ISDN NEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN NEXT
TCM-ISDN NEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN NEXT
The highest subcarrier index that can be used for downstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSC = 256 for a downstream
channel using the frequency band up to 1.104MHz; NSC = 512 for a downstream channel
using the frequency band up to 2.208MHz.
Sliding Window frame counter10 consecutive DMT symbols (except for sync symbols) according to TTR timing
TCM-ISDN Timing Reference
Timing reference used in ATU-C
Timing reference used in ATU-R
Unit Interval

-6-

Q.3

Reference Models

Q.3.1

ATU-C transmitter reference model (replaces figures in 5.1)

See Figure Q.1 and Figure Q.2.
"Bits""Bits" &"Gains"
2*NSC-1

AS0
AS1
AS2
AS3
LS0
LS1
LS2
NTR

crcf
Mux/
Sync
Control

crci

scram
&
FEC

scram
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

2*NSC-2
480
IDFT

OutputParallel/
SerialBuffer

1
n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to NSC-1
Constellation
Encoder Input
Data Frame

U-C

T1532760-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure Q.1/G.992.1 – ATU-C transmitter reference model for STM transport-7-

"Bits""Bits" &"Gains"
2*NSC-1

AS0
ATM0

Cell TC
crcf

AS1
ATM1

Cell TC

NTR

Mux/
Sync
Control
crci

scram
&
FEC

scram
&
FEC

Rate
converterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

2*NSC-2
480
IDFT
1

OutputParallel/
SerialBuffer

n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to NSC-1
Constellation
Encoder Input
Data Frame

U-C

T1532770-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure Q.2/G.992.1 – ATU-C transmitter reference model for ATM transport-8-Q.3.2

ATU-R transmitter reference model (replaces figures in 5.2)

See Figure Q.3 and Figure Q.4.

"Bits""Bits" &"Gains"

LS0

63
crcf

LS0
LS1

Mux/
Sync
ControlLS2

crci

scrambler&
FEC

scrambler
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

62
59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR

B
FEC Output
Data Frame

C
Constellation
Encoder Input
Data Frame

Zi
i=1 to 31
U-R

T1532780-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (276 kHz).

Figure Q.3/G.992.1 – ATU-R transmitter reference model for STM transport-9-

"Bits"63

LS0Cell TC

ATM0

LS1Cell TC

ATM1"Bits" &"Gains"

crcf
Mux/
Sync
Control
crci

scrambler&
FEC

scrambler
&
FEC

62

Rate
converterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR
B
FEC Output
Data FrameZi
C
i=1 to 31
Constellation
Encoder Input
Data Frame

U-R

T1532790-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (276 kHz).

Figure Q.4/G.992.1 – ATU-R transmitter reference model for ATM transport- 10 -

Q.3.3

ATU-C/R transmitter timing model (replacement for 5.3)

Q.3.3.1

TCM-ISDN crosstalk timing model (new)Figure Q.5 shows the timing chart of the crosstalk from TCM-ISDN.

TTR
377 UI
receive ISDN

transmit ISDNCO

0 ≤ propagation delay ≤ 16 UI
RT

6-7.5 UI

377 UI

receive ISDN

transmit ISDN

FEXTR

NEXTR

SC
TTRC

ATU-C TX

Frame Frame0 ≤ propagation delay ≤ 18.5 UI

Received
TTRC

SR

TTRR
NEXTC
ATU-R TXFEXTC

Frame Frame
T1532800-99

1 UI = 3.125 µs
FEXTR and NEXTR are estimated by ATU-CFEXTC and NEXTC are estimated by ATU-R
TTR

TCM-ISDN timing reference

TTRC

Timing reference used in ATU-C

Received TTR C Received TTRC at ATU-R
TTRRTiming reference used in ATU-R

SC

55 × 0.9058 µs: Offset from TTR to TTRC

SR

–42 × 0.9058 µs: Offset from received TTRC to TTRR

Figure Q.5/G.992.1 – Timing chart of the TCM-ISDN crosstalk

The data stream of TCM-ISDN is transmitted in TTR period. CO transmits the stream in the first half of the TTR period
and RT transmits in the second half of the TTR period. ATU-C receives NEXT noise from the ISDN in the first half of
the TTR period and FEXT noise from the ISDN in the second half of the TCM-ISDN period. On the other hand,
ATU-R receives FEXT noise from the ISDN in the first half of the TTR period and NEXT noise from the ISDN in thesecond half of the TTR period.

- 11 -

As defined in Q.7.6.2 and Q.7.8.3, the ATU-C shall estimate the FEXTR and NEXTR duration at ATU-R, and the
ATU-R shall estimate FEXTC and NEXTC duration at ATU-C taking propagation delay on the subscribe line into
consideration.
The ATU-C shall transmit any symbols by synchronizing with the TTRC. The ATU-R shall transmit any symbols
synchronizing with the TTRR generated from received TTRC.
Q.3.3.2

Sliding window (new)Figure Q.6 shows the timing chart of the transmission for the Annex Q downstream at ATU-C.
Hyperframe = 345 symbols

TTRC
Crosstalk
period

FEXTR

FEXTR

FEXTR

FEXTR
NEXTR

NEXTR

ATU-C
T Frame
SWB
T1532810-99

FEXTR symbol
NEXTR symbol

Sliding Window

Figure Q.6/G.992.1 – Sliding window for downstream symbols

The Sliding Window defines the transmission symbols under the crosstalk noise environment synchronized to theperiod of TTR. The FEXTC/R symbol represents the symbol completely inside the FEXTC/R duration. The NEXTC/R
symbol represents any symbol containing the NEXTC/R duration. Thus, there are more NEXTC/R symbols than
FEXTC/R symbols.
The ATU-C decides which transmission symbol is FEXTR or NEXTR symbol according to the sliding window andtransmits it with the corresponding bit table. Similarly, the ATU-R decides the transmission symbol is a FEXTC or
NEXTC and transmits it with the corresponding bit table. Although the phase of the sliding window is asynchronouswith TTRC/R, the pattern is fixed to the 345 frames of the hyperframe.
Q.3.3.3

ATU-C Symbol Synchronization to TTR (new)345 symbols are 34 cycles with cyclic prefix of TTRC (or 32 cycles of TTRC without cyclic prefix). This implies a PLL
lock at the ATU-R.
Q.3.3.4

Dual Bitmap switching (new)The ATU-C transmits FEXTR symbols using Bitmap-FR (in FEXTR duration), and transmits NEXTR symbols using
Bitmap-NR (in NEXTR duration) according to the result of initialization. The ATU-R transmits FEXTC symbols using
Bitmap-FC (in FEXTC duration), and transmits NEXTC symbols using Bitmap-NC (in NEXTC duration) in the samemanner.
The ATU-C shall have the capability to disable Bitmap-NC and Bitmap-NR (see Q.4.5 and Q.5.3).

- 12 -

Q.3.3.5

Loop timing at ATU-R (new)The phase relation between received symbol and transmitted symbol of ATU-R at the reference point U-R shall meetthe phase tolerances as shown in Figure Q.7.
(point U-R)
ATU-R receive
DMT symbol

ATU-R transmit
DMT symbol
T1532820-99±4.5 µs + SR

Figure Q.7/G.992.1 – Loop timing for ATU-R

Q.4

ATU-C functional characteristics (pertains to clause 7)

Q.4.1

STM transmission protocols specific functionality (pertains to 7.1)

Q.4.1.1

ATU-C input and output V interface for STM transport (replaces figure in 7.1.1)

See Figure Q.8.

- 13 -

AS0 (n0 × 32 kbit/s)
AS1 (n1 × 32 kbit/s)
AS2 (n2 × 32 kbit/s)
AS3 (n3 × 32 kbit/s)
Digital
Network

twisted pair

LS0 ("C"; 16 or m0 × 32 kbit/s)

ATU-C

LS1 (m1 × 32 kbit/s)
LS2 (m2 × 32 kbit/s)
NTR
TTR
Operations, maintenance and control

T1532830-99

V-C
NOTE 1 – Optional bearer channels (both duplex and simplex) and features are shown with dotted lines.
NOTE 2 – TTR may be generated in the ATU-C without being provided from the V-C reference point.

Figure Q.8/G.992.1 – ATU-C functional interfaces for STM transport at the V-C reference point

Q.4.1.2

Payload transfer delay (supplements 7.1.4)

Since Annex Q uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.1.4. The
additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
Q.4.2
Q.4.2.1

ATM transmission protocols specific functionalities (pertains to 7.2)
ATU-C Input and Output V interface for ATM transport (replaces figure in 7.2.1)

See Figure Q.9.

- 14 -

ATM layer

ATM0
Tx_ATM0P
O
RT0

Tx_Cell_Handshake0
Rx_ATM0
Rx_Cell_Handshake0

ATM1
P
O
R
T
1

Twisted pair

Tx_ATM1
ATU-C
Tx_Cell_Handshake1
Rx_ATM1
Rx_Cell_Handshake1
NTR

and interface to
Digital network

TTR
Operations, administration,
maintenance and control
V-C

T1532840-99

NOTE – TTR can be generated in the ATU-C without being provided from the V-C reference point.

Figure Q.9/G.992.1 – ATU-C functional interfaces to the ATM layer at the V-C reference point

Q.4.2.2

Payload transfer delay (supplements 7.2.2)

Since Annex Q uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.2.2. The
additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
Q.4.3
Q.4.3.1

Framing (pertains to 7.4)
Superframe structure (supplements 7.4.1.1)

Since the rate converter reorders the user data and overhead bit-level data to create hyperframes, the input data frames
to the constellation encoder are different than those defined in 7.4.1.1.
Q.4.3.2

Hyperframe structure (replaces 7.4.1.3)

Annex Q uses the hyperframe structure shown in Figure Q.10. Figure Q.10 shows the phase relationship between the
TTRC and the hyperframe at the point U-C. Each hyperframe is composed of 5 superframes, which are numbered from0 to 4. In order to indicate the boundary of the hyperframe, the inverse synch symbol is used for the 4th superframe(SPF#3), which is generated from a tone-by-tone 180-degree phase reversal of the synchronization symbol (see Q.4.7.1)
except for the pilot tone.
The bit-level data stream from the rate-converter is extracted according to the size of Bitmap-FR and Bitmap-NR using
the Sliding Window (see Q.3.3.2).
In order to make the bit rate to be a multiple of 32 kbit/s, the dummy bits are inserted at the end of hyperframe by the- 15 -

rate converter (see Q.4.4.2). The hyperframe is composed of 345 DMT symbols, numbered from 0 to 344. Each symbol
is assigned as FEXTR or NEXTR symbol in a FEXTR or NEXTR duration (see Q.2), and the following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-C transmitter (see Figure Q.11).
For Ndmt = 0, 1, ..., 344

S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > a + b) }elsethen FEXTR symbol
then NEXTR symbol

where a = 1243, b = 1461
Thus, 128 DMT symbols are allocated in the FEXTR duration, and 217 DMT symbols are allocated in the NEXTR
duration. The symbols are composed of:
FEXTR symbol:
Number of symbol using Bitmap-FR
Number of synch symbol
Number of inverse synch symbol
NEXTR symbol:

= 126
=1
=1

Number of symbol using Bitmap-NR= 214

Number of synch symbol=3

During FEXT Bitmap mode, the ATU-C shall transmit only the pilot tone in NEXTR symbols.

- 16 -

5 Superframe (= 340 frames)(point B)
1 Superframe = 68 frames (17 ms)

1 frame = 250 µs
Rate-Converter(point U-C, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#27

TC#33

TTR
ATU-R
Crosstalk

FEXT

NEXT

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol F F F F N N N N N N

FEXTHyperframe = 345 symbols (85 ms)

F F

SPF#1
S

Sliding window

SPF#2
S

S

SPF#3
N F I

I

Inverse synch symbol

S

NEXTR Synch symbol

F

Symbol using Bitmap-FR (FEXTR duration bitmap)

N

Symbol using Bitmap-NR (NEXTR duration bitmap)

S

FEXTR Synch symbol

Figure Q.10/G.992.1 – Hyperframe structure for downstream- 17 -SPF#4
F F

FEXTR duration

1 symbol = 264 µs (544 samples)

NEXT

N
T1532850-99

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

0
10
20
30

1

2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
21
22
23
24
25
26
27
28
29
40
31
32
33
34
35
36
37
38
39
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
SS
61
62
63
64
65
66
67
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100 101
103
104
105
106
107
108
109
110 111101 102
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
SS
132
133
134
135
136
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162 163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181 182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
SS
203
204
205
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233 234
235
236
237
238
239
240
241
242 243
253
244
245
246
247
248
249
250
251
252
263
254
255
256
257
258
259
260
260
262
264
265
266
267
268
269
270
271
272
273
274
276
277
278
279
280
281
282
283
ISS
284
285
286
287
288
289
290
291
292
293
295
296
297
298
299
300
301
302
303
294
304 305
306
307
308
309
310
311
312
313 314
315
316
317
318
319
320
321
322
323
324
334
325
326
327
328
329
330
331
332
333
SS
335
336
337
338
339
340
341
342
343
ISS

Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol
NEXTR data symbol

SS

NEXTR synch symbol
T1535330-00

Figure Q.11/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Downstream

Q.4.3.3

Subframe Structure (replaces 7.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table Q.1. The 34 subframes forma hyperframe.

- 18 -

Table Q.1/G.992.1 – Subframe (downstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

Q.4.3.4

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Inverse Synch Symbol#344 is Synch Symbol

Reduced overhead framing with merged fast and sync bytes (modifies 7.4.3.2)

In S=1/2n framing mode (see §Q.4.9), there are n Sync bytes per symbol time. The contents of the Sync bytes is thesame as in regular framing except that it repeats at n times the rate causing the superframe to be 68/n symbols in length.
The contents of the sync bytes are shown in Table 7-6/G.992.1. In S=1/2n framing mode, “Frame Number” in column 1
in Table 7-6/G.992.1 is replaced by “Sync Byte Index Number”.
As a result of the increase in superframe rate, the superframe contents is carried more frequently. For the case when
N=2, the EOC and AOC bandwidth doubles, thereby transferring actual messages at twice the rate. The CRC byte iscarried twice as frequently and therefore the maximum error rate rises from just over 58 per second to 117 per second.
Where the duration of an error condition is measured, this needs to be taken into consideration. The indicator bits arealso sent twice as often, which needs to be taken into consideration for statistics collection.
Q.4.4

Dual Bitmapping and Rate Conversion (replaces 7.15)

The functions of the rate converter (see Q.4.4.2), tone ordering (see Q.4.6), constellation encoding, and gain scaling
shall use one of two bitmaps stored in the ATU. This method is called the dual bitmap.

- 19 -

Q.4.4.1

Dual Bitmap (new)The Dual Bitmap method has individual bit rates under the FEXT and NEXT noise, and this needs an additional bit andgain table, {bi, gi}, and ordered bit table, b'i, for the tone ordering. The dual bitmaps are switched synchronized withthe sliding window pattern of NEXT/FEXT symbols. The number of bits and the relative gains to be used for every tone
are calculated in the bit loading algorithm during the initialization sequence, and transmitted in R-B&G.
Q.4.4.2

Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FR, Bitmap-NR and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amount of fast and interleaved data in Bitmap-FR and Bitmap-NR shall be calculated with thefollowing formulae and illustrated in Figure Q.12:
If tRf ≤ nRmax:n Rf = t Rf
nRi = nR − nRf
f Rf = t Rf
f Ri = f R − f Rf
If tRf > nRmax:

nRf = nR max

nRi = 0⎧⎡ t Rf × 10 − nRf × 6 ⎤⎪ f Rf 4 = ⎢
⎥
4
⎢
⎥
⎪
f Rf = ⎨⎡ t Rf ×10 − nRf × 7 ⎤⎪⎥⎪ f Rf 3 = ⎢3⎢⎥⎩⎧⎪ f Ri 4 = f R = f Rf 4
f Ri = ⎨⎪⎩ f Ri3 = f R − f Rf 3
Where:
tRf
tRi
fRf and nRf
fRf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FR and Bitmap-NR, respectively.
is the number of fast bits in Bitmap-FR if the subframe (see Q.4.3.3) contains 3 Bitmap-FR except
for synch symbols.
fRf4
is the number of fast bits in Bitmap-FR if the subframe contains 4 Bitmap-FR except for synch
symbols.
fRi and nRi
are the numbers of interleaved bits in Bitmap-FR and Bitmap-NR, respectively.
nR
is the number of total bits in Bitmap-NR, which is specified in the B&G tables.
During FEXT Bitmap mode, nRf and nRi are zero.
To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tRf ≤ nRmax:- 20 -

dummy Rf = 0

dummy Ri = ( f Ri × 126 + nRi × 214) − t Ri × 340
If tRf > nRmax:()
dummy Rf 3 = ( f Rf × 3 + nRf × 7 ) − t Rf × 10

dummy Rf 4 = f Rf × 4 + nRf × 6 − t Rf ×10

dummy Ri = ( f Ri 4 × 96 + f Ri3 × 30 ) − t Ri × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FR constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:

dummySRf = f Rf 3 − f Rf 4
The receiver shall determine Bitmap-FR and Bitmap-NR so that dummyRi is less than 126, dummyRf4 is less than 4 anddummyRf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.

- 21 -

#335#336#337#338#339#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25 #26 #27 #28 #29

tRi

Interleaved DatatRj

Fast Data

NOTE – Bit Ordering:
The earlier bit is located at the bottom
each symbol in this figure.
Rate Converter

Order

When tRf ≤ nRmax

fRi =fR – fRf

fR#4 #5 #6 #7 #8 #9

dummyRi#21 #22 #23#10 #11 #12 #13#0 #1 #2 #3#14 #15 #16 #17 #18 #19 #20#343#339#340#341#342#24 #25 #26 #27 #28 #29

nRinnRf=tRf R

fRf – tRf
FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols
Symbols
Subframe

NEXT
Symbols
Subframe

FEXT
NEXT
Symbols Symbols
Subframe

When tRf > nRmax#0 #1 #2 #3#21 #22 #23#10 #11 #12 #13

dummyRi

fRi3

fRi4
dummyRf4

fR#335#336#337#338

dummyRf4

dummyRf3

dummy Rf4

fRf3
fRf4

#4 #5 #6 #7 #8 #9#14#15 #16 #17#18 #19 #20#26 #27 #28 #29#339#340#341#342#343

nRf = n
FEXTNEXT
Symbols Symbols
Subframe

FEXT
Symbols

NEXT
Symbols

Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe
T1532860-99

Figure Q.12/G.992.1 – Bit distribution for Rate Converter under Dual latency and Dual Bitmap mode

Q.4.5

FEXT Bitmapping (replaces 7.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (Q.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures Q.10 and Q.15).
Annex Q does not support the FEXT Bitmapping mode.
Q.4.6

Tone Ordering (replacement for 7.7)

A DMT time-domain signal has a high peak-to-average ratio (its amplitude distribution is almost Gaussian), and large
values may be clipped by the digital-to-analogue converter. The error signal caused by clipping can be considered as anadditive negative impulse for the time sample that was clipped. The clipping error power is almost equally distributed
across all tones in the symbol in which clipping occurs. Clipping is therefore most likely to cause errors on those tones- 22 -

that, in anticipation of a higher received SNR, have been assigned the largest number of bits (and therefore have thedensest constellations). These occasional errors can be reliably corrected by the FEC coding if the tones with the largest
number of bits have been assigned to the interleave buffer.
The numbers of bits and the relative gains in two bitmaps to be used for every tone are calculated in ATU-R receiver,and sent back to ATU-C according to a defined protocol (see 10.9.14). The pairs of numbers are typically stored, in
ascending order of frequency or tone numbers i, in bit and gain tables for Bitmap-FR and Bitmap-NR.
For Bitmap-FR, the "tone-ordered" encoding shall first assign fRf bits from the rate converter (see Q.4.4.2) to the tones
with the smallest number of bits assigned to them, and the remaining fRi bits to the remaining tones. For Bitmap-NR, it
shall first assign nRf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nRi bits to the remaining tones.
All tones shall be encoded with the number of bits assigned to them; one tone in each bitmap may therefore have a
mixture of bits from the fast and interleaved buffers.
The ordered bit tables b'iF and b'iN shall be based on the original bit tables biF and biN as follows:
For k = 0 to 15 {From the bit table, find the set of all i with the number of bits per tone bi = k
Assign bi to the ordered bit allocation table in ascending order of i}
Two ordered bit tables for Bitmap-FR and Bitmap-NR shall be prepared. A complementary de-ordering procedure
should be performed in ATU-R receiver. It is not necessary, however, to send the results of the ordering process to thereceiver because the bit tables FR and NR were originally generated in ATU-R, and therefore those tables have all theinformation necessary to perform the de-ordering.
Q.4.7
Q.4.7.1

Modulation (pertains to 7.11)
Inverse Synchronization Symbol (replaces 7.11.4)

Except for the pilot tone, Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phasereversal of Synchronization symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
Q.4.7.2

Data subcarriers (modifies 7.11.1.1)

The channel analysis signal defined in 10.6.6 allows for a maximum of NSC-1 carriers (at frequencies n∆f , n = 1 to
NSC-1) to be used.
Q.4.7.3

Nyquist frequency (modifies 7.11.1.3)

The carrier at the Nyquist frequency (#NSC) shall not be used for user data and shall be real valued; other possible uses
are for further study.
Q.4.7.4

Modulation by the inverse discrete Fourier transform (replaces 7.11.2)

The modulating transform defines the relationship between the 2*NSC real values xn and the Zi:

xn =2* NSC −1⎛ jπni ⎞∑ exp⎜⎝ NSC ⎟⎠Zi =0i

for n = 0 to 2 * NSC − 1(7-21)The value of NSC shall be 1024 for this Annex. However, the PSD mask limits the highest used subcarrier index to 869.
The constellation encoder and gain scaling generate only NSC-1 complex values of Zi. In order to generate real valuesof xn, the input values (NSC-1 complex values plus zero at DC and one real value for Nyquist if used) shall beaugmented so that the vector Z has Hermitian symmetry. That is,- 23 -

Zi = conj (Z'2*NSC-i)
Q.4.7.5

for i = NSC+1 to 2*NSC-1 (7-22)

Synchronization symbol (modifies 7.11.3)

The synchronization symbol permits recovery of the frame boundary after micro-interruptions that might otherwise
force retraining.
The data symbol rate, fsymb = 4 kHz, the carrier separation, ∆f = 4.3125 kHz, and the IDFT size, N = 2*NSC, are suchthat a cyclic prefix of 15.625%*NSC samples could be used. That is, when NSC = 256, there are 40 samples in thecyclic prefix.
(512 + 40) × 4.0 = 512 × 4.3125 = 2208

(7-23)

The cyclic prefix shall, however, be shortened to 12.5%*NSC samples, and a synchronization symbol (with a nominal
length of NSC*2.125 samples) is inserted after every 68 data symbols. That is,(2 + 0.125)*NSC × 69 = (2 + 0.15625)*NSC × 68

(7-24)The data pattern used in the synchronization symbol shall be the pseudo-random sequence PRD, (dn, for n = 1 to
2*NSC) defined by:
dn = 1for n = 1 to 9
(7-25)
dn = dn-4 ⊕ dn-9

for n =10 to 2*NSC(7-26)

The first pair of bits (d1 and d2) shall be used for the DC and Nyquist subcarriers (the power assigned to them is zero,so the bits are effectively ignored); the first and second bits of subsequent pairs are then used to define the Xi and Yi for
i = 1 to NSC-1 as shown in Table 7-13.
The period of the PRD is only 511 bits, so dn+511 is equal to dn. The d1-d9 shall be re-initialized for eachsynchronization symbol, so each symbol uses the same data.
The two bits that modulate the pilot carrier, shall be overwritten by {0,0}: generating the {+,+} constellation.
The minimum set of subcarriers to be used is the set used for data transmission (i.e. those for which bi > 0); subcarriers

for which bi = 0 may be used at a reduced PSD as defined in transmit PSD paragraphs of Annexes A, B and C. The data
modulated onto each subcarrier shall be as defined above; it shall not depend on which subcarriers are used.
Q.4.7.6

Cyclic prefix (replaces 7.12)

The last 12.5%*NSC samples of the output of the IDFT (xn for n = 2*NSC-0.125*NSC to 2*NSC-1) shall be
prepended to the block of 2*NSC samples and read out to the digital-to-analogue converter (DAC) in sequence. For
example, when NSC=256, the subscripts, n, of the DAC samples in sequence are 480 ... 511, 0 ... 511.
The cyclic prefix shall be used for all symbols beginning with the C-RATES1 segment of the initialization sequence, as
defined in 10.6.2.
Q.4.8

ATU-C Downstream transmit spectral mask (replaces 7.14)

The downstream spectral mask of Annex Q is as specified in this section. Annex Q does not support overlapped
spectrum. Therefore, C-MSG1 bit 16 shall be set to 0, and the PSD mask specified in § Q.4.8.1 shall be used.
Q.4.8.1

Downstream non-overlapped PSD mask definition

The non-overlapped PSD mask is defined with absolute peak values in Figure Q.13. The low frequency stop band isdefined for frequencies below 138 kHz (tone 32); the high frequency stop band is defined at frequencies greater than3750 kHz (tone 869). The in-band region of this PSD mask is the frequency band from 138 kHz to 3750 kHz.

- 24 -

–18 dB/octave

PSD indBm/Hz–36.5 dBm/Hz peak PSD–2.9 dB/octave

36 dB/octave-76.5 dBm/Hz–-100 dBm/Hz peak PSD
in 10 kHz window

4.63 dB/octave–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHz-50 dBm/Hz

peak PSD
in 1 MHz window
above 3750 kHz–357 dB/octave–44.2 dBm/Hz–72.5 dBm/Hz–92.5 dBm/Hz

04

80 138

1104

3750

1622

Frequency band f (kHz)0<f<4
4 < f < 80
80 < f < 138
138 < f < 1104
1104 < f < 1622
1622 < f < 3750
3750 < f < 3925
3925 < f < 12000

3925–110 dBm/Hz–112 dBm/Hz

4545

12000

7225

Frequency
in kHzEquation for line (dBm/Hz)-97.5-92.5 + 4.63*log2(f/4)-72.5 + 36*log2(f/80)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 2.9*log2(f/1622)-76.5 - 357*log2(f/3750)-100

Frequency (kHz)
0
4
4
10
80
138
138
1104
1622

PSD level (dBm/Hz)
-97.5
-97.5
-92.5
interpolated
-72.5
-44.2
-36.5
-36.5
-46.5

Measurement BW
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz3750
3750
3925 – 12000

-50
-76.5
-100

10 kHz
10 kHz
10 kHz

Additionally the PSD mask shall satisfy the following requirements:
Frequency (kHz)
3925
4545
7225
12000
NOTE 1 –NOTE 2 –NOTE 3 –NOTE 4 –PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint withfrequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.

- 25 -NOTE 5 –NOTE 6 –The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued
the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that
this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.
Figure Q.13: Non-overlapped Downstream Channel PSD Mask

Spectral Shaping of the In-Band Region defined in Q.4.8.2 and Transmit Signals with Limited Transmit Power definedin Q.4.8.3 shall be applied.

Q.4.8.2

Spectral Shaping of the In-Band Region of the PSD Spectrum

In order to shape the ATU-C PSD, frequency dependent gains, called spectral shaping values (ssvi ), shall be applied oneach tone during initialization and showtime. The ssvi values shall be represented with 1 bit before and 10 bits after thedecimal point.
Table Q.2 defines the corner points for the nominal PSD shape of the inband region as gain in dB, i.e log_ssvi. Log_ssvi
on other tones shall be linearly interpolated between corner points on a logarithmic scale for the gain (dB) and a linear
scale for the frequency (Hz). Note that the corner points defined in Table Q.2 are relative values.
The spectral shaping values shall be converted from logarithmic scale (log_ssvi, dB values) to linear ssvi values
according to:log_ ssvi⎞⎛
Round ⎜⎜1024 × 10 20 ⎟⎟⎠⎝ssvi =
1024

These points are not passed at initialization for the nominal PSD shape but are provided here for reference. However,for additional spectral shaping (see Q.4.8.4), parameters are passed during G.994.1.
The combined accuracy of the process of linear interpolation of the log_ssvi values and the process of conversion tolinear ssvi values shall be strictly less than one half lsb of the 10 bit after the decimal point format of the linear ssvi
values. No error shall be introduced when log_ssvi equals 0dB or is interpolated between log_ssvi values, which equal
0dB.
NOTE 1:NOTE 2:

The above definition ensures that the maximum deviation between ssvi values used by transmitter andreceiver is one lsb.
The above needs an accuracy that is strictly < 1/2 lsb. An accuracy of = 1/2 lsb, will lead to inaccurate
results.

Table Q.2: Corner points for the non-overlapped nominal in-band PSD shape.
Tone Index
32

Log_ssvi (dB)
0

256
376
869

0
–10
–13.5

Comments
138 kHz defines the beginning of the inband region. No shaping is applied in
the low stop band.
1104 kHz
1622 kHz ( –10 = -50 - Nominal_PSD_lowband)
3750 kHz ( –13.5 = -53.5 - Nominal_PSD_lowband)

The absolute values of the transmit PSD are obtained by scaling the relative shaping values with a
NOMINAL_PSD_lowband, defined for the lower in-band frequencies. Note that the nominal in-band transmit PSD isfrequency dependent. The NOMINAL_PSD_lowband is –40 dBm/Hz (flat from 138 kHz to 1104 kHz) for the nonoverlapped spectrum.

- 26 -NOTE 3: In-band PSD spectral shaping is applied prior to the IFFT.
NOTE 4: The value of MAXNOMATPds may be limited by regional regulations.
Q.4.8.3

Transmit Signals with Limited Transmit PowerFor cases where the transmit signal must be limited to a maximum aggregate total power (e.g. ATPdsmax = +20 dBm),thena)During initialization the PSD transmit level is specified as an offset from the nominal value, i.e.
(Nominal_PSD_lowband + ssvi – x – power cutback) dB, and all values of gi = 1 for the offset value x and power
cutback. The value of x shall be the greater of 0 dB and (21.1 – ATPdsmax) dB. For ATPdsmax = 20 dBm, thecorresponding value of x shall be 1.1 dB.

b)

If bi>0, then valid range for gi is [-14.5 to +2.5+x] (dB) ;If bi>0, then gi shall be in the [gsync – 2.5 to gsync + 2.5] (dB) range;
If bi=0, then gi shall be equal to 0 (linear) or in the [-14.5 to gsync] (dB) range;
For G.992.1 annex Q, gsync <= x dB

The gi values shall be constrainted by following relation:
Constraint on gi values

511
i =6

Q.4.8.4

511∑ ssv ∗ g ≤ ∑ ssv
2

i

2

i

i =6

2

i

Additional inband spectral shaping

An ATU-R may request additional downstream inband spectral shaping by passing parameters to the ATU-C in a
G.994.1 CLR, MP, or MS message. The ATU-C may select additional downstream inband spectral shaping by passing
parameters to the ATU-R in a G.994.1 CL or MS message. Within the framework of G.994.1, the ATU-C has the ability
to make the final decision on the downstream inband PSD shape to be used.
The additional inband spectral shaping parameters are listed in Q.7.2.2 and defined in Q.7.3. If the Additional inband
spectral shaping Spar(2) bit is set to ONE in Table Q.6.2, its associated Npar(3) octets in Tables Q.6.2.1 to Q.6.2.1.5
define the inband spectral shape. If the additional inband spectral shaping Spar(2) bit is set to ZERO, its associatedNpar(3) octets are not transmitted and the nominal inband PSD shape defined in Q.4.8.2 shall be used. These Npar(3)octets define the downstream PSD levels in the low band (between 138 and 1104 kHz), at 1622 kHz and at 3750 kHz.
The PSD levels between 1104 kHz and 1622 kHz, and between 1622 kHz and 3750 kHz are linearly interpolated in log
scale. The defined values are the PSD level in dB below the NOMINAL_PSD_lowband of –40dbm/Hz. For example, if
all three values are set to 20 dB, the result will be a flat PSD of –60dbm/Hz. If the three values are set to 2 dB, 12 dB
and 15.5 dB, the result is the PSD defined in Q.4.8.1 reduced by 2dB. In order not to violate the PSD mask defined in
Q.4.8.1, the second value shall be no less than 10 dB and the third value shall be no less than 13.5 dB.

Q.4.8.5

Egress control

G.992.1 Annex Q equipment shall be able to reduce the PSD below –80 dBm/Hz for the Amateur radio bands between
1.81 MHz and 2.00 MHz, and between 3.5 MHz and 3.8 MHz. The ATU-C may apply additional spectral shaping as
described in Q.4.8.4 to help achieve this requirement.

Q.4.9

Support of higher downstream bit rates with S = 1/2n (replaces 7.6.4)

With a rate of 4000 data frames per second and a maximum of 255 bytes (maximum RS codeword size) per data frame,
the ADSL downstream line rate is limited to approximately 8 Mbit/s per latency path. The line rate limit can be- 27 -

increased beyond this for the interleaved path by mapping 2n RS codewords into one FEC data frame (i.e. by using S =1/2n in the interleaved path). S = 1/2n shall be used in the downstream direction only over bearer channel AS0.
For a selected value of n ≥ 1, the KI data bytes per interleaved mux data frame shall be packed into 2n RS codewords,
split into n equal parts, each consisting of 2 consecutive RS codewords. This forces rate adaptation to occur in 32n
kbit/s increments. Each of the n parts of the data frame shall begin with a sync byte and shall obey the rules defined inTable Q.3 for insertion of dummy bytes. The smallest value of n that can support the KI data bytes shall be used.
Support of S = 1/2 (i.e., n=1), S = 1/4 (i.e., n=2), S = 1/6 (i.e., n=3), and S = 1/8 (i.e., n=4), is mandatory.

The resulting data frame structure shall be as shown in Figure Q.14.
N1
Sync
Byte

PayloadN2 = N 1 or N 1-1

R

PayloadR

N2n-1 = N1
Sync
Byte

PayloadN2n = N2

R

PayloadR

NI
Figure Q.14 – Data frame for S = 1/2n mode
When KI is divisible by 2n, the 2n codewords have the same length N2i-1 = N2i = (KI/2n + RI) for i = 1 to n, otherwise
the odd numbered codewords are equal and are one byte longer than the even numbered codewords, i.e. N2i-1 =(KI + n)/2n + RI bytes, and N2i = (KI – n)/2n + RI bytes for i = 1 to n. For the FEC output data frame, NI =

∑ N,
n

i =1

i

with NI < 512n - 1 bytes.
The convolutional interleaver requires all codewords to have the same odd length. To achieve the odd codeword length,
insertion of dummy (not transmitted) bytes may be required. For S = 1/2n, the dummy byte addition to the odd
numbered and/or even numbered codewords at the input of the interleaver shall be as in Table Q.3.

Table Q.3/G.992.1 –Dummy byte insertion at interleaver input for S = 1/2n
N2i-1
Odd
Even
Odd
Even

N2i
Odd
Even
Even
Odd

Dummy Byte Insertion Action
No action
Add one dummy byte at the beginning of all codewords
Add one dummy byte at the beginning of each even numbered codeword
Add one dummy byte at the beginning of each odd numbered codeword and two dummy bytes
at the beginning of each even numbered codeword [the de-interleaver shall insert one dummy
byte into the de-interleaver matrix on the first byte and the (D + 1)th byte of the corresponding
codeword to make the addressing work properly]

Q.5

ATU-R Functional Characteristics (pertains to clause 8)

Q.5.1

Framing (pertains to 8.4)

Q.5.1.1

Superframe structure (replaces 8.4.1.1)

The superframe structure of ATU-R transmitter is identical to that of ATU-C transmitter, as specified in Q.4.3.1.
Q.5.1.2

Hyperframe structure (replaces 8.4.1.3)

The hyperframe structure of ATU-R transmitter is functionally similar to that of ATU-C transmitter, except that the- 28 -

inverse synch symbol is used in the 1st superframe (SPF#0) (see Figure Q.15). The hyperframe is composed of 345
DMT symbols, numbered from 0 to 344. Each symbol is under FEXTC or NEXTC duration (see Q.5.3), and thefollowing numerical formula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-R
transmitter (see Figure Q.16).
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbol
then NEXTC symbol

128 DMT symbols are allocated in the FEXTC duration, and 217 DMT symbols are allocated in the NEXTC duration.
The symbols are composed of:
FEXTC symbol:
Number of symbol using Bitmap-FC
Number of synch symbol
Number of inverse synch symbol
NEXTC symbol:
Number of symbol using Bitmap-NC
Number of synch symbol

= 126
=1
=1
= 214
=3

During FEXT Bitmapping mode, the ATU-R shall not transmit any signal.

- 29 -

5 Superframe (= 340 frames)(point B)

1 Superframe = 68 frames (17 ms)

1 frame = 250 µs

Rate-Converter(point U-R, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#6

TC#33

TTRR
ATU-R
Crosstalk

NEXT

NEXT

FEXT
Hyperframe = 345 symbols (85 ms)

FEXT

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol N N N N N F F F F N N N

SPF#2

SPF#1

N F

F I F N

S

S

SPF#3

SPF#4

S

S
T1532870-99

Sliding window

FEXTC duration

1 symbol = 264 µs (68 samples)
I

Inverse synch symbol

S

NEXTC Synch symbol

F

Symbol using Bitmap-FC (FEXTC duration bitmap)

N

Symbol using Bitmap-NC (NEXTC duration bitmap)

S

FEXTC Synch symbol

Figure Q.15/G.992.1 – Hyperframe structure for upstream- 30 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

ISS

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

101

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

SS

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

17

173

174

175

176

177

178

179

180

181

172
182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

SS

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

244

245

246

247

248

249

250

251

252

253

24

243

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

SS

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

SS

ISS Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol SS NEXTR synch symbol
NEXTR data symbol

T1535340-00

Figure Q.16/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Upstream

Q.5.1.3

Subframe structure (replaces 8.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table Q.4. The 34 subframes forma hyperframe.

- 31 -

Table Q.4/G.992.1 – Subframe (upstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

Q.5.2

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Inverse Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Synch Symbol#344 is Synch Symbol

Dual Bitmapping and rate conversion (replaces 8.15)

The function of the rate converter (see Q.5.2.2), tone ordering (see Q.5.4), constellation encoding, and gain scaling shalluse one of two bitmaps stored in the ATU. This method is called the dual bitmap.
Q.5.2.1

Dual Bitmap (new)The Dual Bitmap switching shall be the same as for the downstream data, specified in Q.4.4.1. The number of bits andthe relative gains to be used for every tone are calculated in the bit loading algorithm during the initialization sequence,and transmitted in C-B&G.
Q.5.2.2
Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FC, Bitmap-NC and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amounts of fast and interleaved data in Bitmap-FC and Bitmap-NC shall be calculated in thefollowing formulae:
If tCf ≤ nCmax:- 32 -

nCf = tCf
nCi = nC − nCf
f Cf = tCf
f Ci = f C − f Cf
If tCf > nCmax:

nCf = nC max

nCi = 0⎧⎡ tCf × 10 − nCf × 6 ⎤⎪ f Cf 4 = ⎢
⎥
4
⎪
⎢
⎥
f Cf = ⎨⎡ tCf ×10 − nCf × 7 ⎤⎪⎥⎪ f Cf 3 = ⎢3⎢⎥⎩⎧ f Ci 4 = f C − f C 4
f Ci = ⎨⎩ f Ci 3 = f C − f Cf 3
Where:
tCf
tCi
fCf and nCf
fCf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of fast bits in Bitmap-FC if the subframe (see Q.5.1.3) contains 3 Bitmap-FC except
for synch symbols.
fCf4
is the number of fast bits in Bitmap-FC if the subframe contains 4 Bitmap-FC except for synch
symbols.
fCi and nCi
are the numbers of interleaved bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of total bits in Bitmap-NC, which is specified in the B&G tables.
nC
During FEXT Bitmap mode, nCf and nCi are zero.

To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tCf ≤ nCmax:

dummyCf = 0

dummyCi = ( f Ci × 126 + nCi × 214) − tCi × 340
If tCf > nCmax:()
dummyCf 3 = ( f Cf × 3 + nCf × 7 ) − tCf ×10

dummyCf 4 = f Cf × 4 + nCf × 6 − tCf ×10

dummyCi = ( f Ci 4 × 96 + f Ci 3 × 30) − tCi × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FC constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:
dummySCf = fCf3 – fCf4

- 33 -

The receiver shall determine Bitmap-FC and Bitmap-NC so that dummyCi is less than 126, dummyCf4 is less than 4 anddummyCf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.
Q.5.3

FEXT Bitmapping (replaces 8.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (Q.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures Q.10 and Q.15).
Annex Q does not support the FEXT Bitmapping mode.
Q.5.4

Tone Ordering (pertains to 8.7)

The tone ordering algorithm shall be the same as for the downstream data, specified in Q.4.4.
For Bitmap-FC, the "tone-ordered" encoding shall first assign fCf bits from the rate converter (see Q.5.2.2) to the tones
with the smallest number of bits assigned to them, and the remaining fCi bits to the remaining tones. For Bitmap-NC, it
shall first assign nCf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nCi bits to the remaining tones. Two ordered bit tables for Bitmap-FC and Bitmap-NC shall be prepared.
Q.5.5

Modulation (pertains to 8.11)

Q.5.5.1

Inverse synchronization symbol (replaces 8.11.4)

Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phase reversal of Synchronization
symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
Q.5.5.2

Gain scaling in synchronization symbol (new)At initialization time, the sync symbol reference transmit PSD level shall be set at the nominal PSD level+10log(gsync2) dBm/Hz, with gsync2 defined as the average gi2 value over the used (i.e. bi > 0) subcarriers in theNEXT or FEXT bitmap, whichever results in the highest average gain. The sync symbol reference transmit PSD shallnot be updated with used subcarrier gain changes during SHOWTIME.
Q.5.6

ATU-R Upstream Transmit Spectral Mask (supplements 8.14)

The upstream spectral mask of Annex Q uses the same mask as Annex A.
Q.6

EOC Operation and Maintenance (pertains to clause 9)

Q.6.1

ADSL line related primitives (supplements 9.3.1)

Q.6.1.1

ADSL line related near-end defects (supplements 9.3.1.3)

Two near-end defects are further defined:••

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.
Severely errored frame (SEF): A SEF defect occurs when the content of two consecutively received ADSL
synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R, does notcorrelate with the expected content over a subset of the tones. An SEF defect terminates when the content of twoconsecutively received ADSL synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR
duration at ATU-R, correlate with the expected contents over the same subset. The correlation method, theselected subset of tones, and the threshold for declaring these defect conditions are implementation discretionary.

- 34 -

Q.6.1.2

ADSL line related far-end defects (supplements 9.3.1.4)

Loss-of-signal is further defined:•

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.

Q.6.2

Test Parameters (supplements 9.5)

Q.6.2.1

Near-end test parameters (supplements 9.5.1)

The near-end primitives are further defined:••

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio (SNR) margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.

Q.6.2.2

Far-end test parameters (supplements 9.5.2)

The far-end primitives are further defined:
•
•

Q.6.3

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio SNR margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.
Data registers in the ATU-R (supplements 9.2.4)

For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7

Initialization (pertains to clause 10)

Q.7.1

Initialization with Hyperframe (replaces 10.1.5)

The exchange of messages between ATU-C and ATU-R should be performed in FEXTC and FEXTR. The DMT
symbol has two symbol rates: one is 4.3125 kbaud for the symbol without a cyclic prefix, and the other is 4 x 69/68
kbaud for the symbol with a cyclic prefix. 32 times of the TTR has the same period as 345 times of the 4.3125 kbaud,
and 34 times of the TTR is the same as 345 times of 4 x 69/68 kHz.
During FEXT Bitmap mode, the ATU-R shall not transmit any signal during the NEXTC symbols duration and the
ATU-C shall transmit only the pilot tone as the NEXTR signal except:• C-PILOT1 (C-PILOT1A) which is accompanied by a signal to allow the ATU-C to indicate the phase of TTRC
to the ATU-R (see Q.7.4.1);• C-QUIETn where no signal is transmitted.
The ATU-C begins transmitting C-PILOT1 at the beginning of the hyperframe without cyclic prefix. The ATU-C
informs the phase of the TTRC to ATU-R during C-PILOT1. The ATU-R begins transmitting R-REVERB1 at the
beginning of the hyperframe without cyclic prefix. The ATU-R performs the training of any receiver equalizer using
this phase information of the TTRR generated from received TTRC.
From C-PILOT1 to C-SEGUE1, the following numerical formula gives the information which duration Ndmt-th DMT
symbol belongs to at ATU-R (see Figure Q.17).

- 35 -

For Ndmt = 0, 1, …344
S = 256 x Ndmt mod 2760
if { (S + 255 < a) or (S > a + b) }else
where a = 1243, b = 1461

then FEXTR symbols
then NEXTR symbols

In order to enter C-RATES1 at the beginning of the hyperframe with cyclic prefix, the number of symbols from
C-PILOT1 to C-SEGUE1 shall be a multiple of 345 DMT symbols.
From R-REVERB1 to R-SEGUE1, the following numerical formula gives the information which duration Ndmt-th
symbol belongs to at ATU-C (see Figure Q.18).
For Ndmt = 0, 1, …, 344,
S = 256 x Ndmt mod 2760
if { (S > a) and (S + 255 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols

From C-RATES1 to C-SEGUE3, the number of symbols is a multiple of 345 DMT symbols. The following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-C transmits the message data in
FEXTR symbols (see Figure Q.11).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760
if { (S + 271 ≥ a) and (S ≤ a + b) }else
where a = 1243, b = 1461

then NEXTR symbols
then FEXTR symbols

The ATU-R enters R-REVERB3 at the beginning of the hyperframe with cyclic prefix, which is extracted fromreceived signal. From R-REVERB3 to R-SEGUE5, the number of symbols is a multiple of 345 DMT symbols. The
following numerical formula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-R transmits
the message data in FEXTC symbols (see Figure Q.16).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols- 36 -

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14

0

1

2

3

4

5

6

7

8

9

10

11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
107
97
98
99
100
101
102
103
104
105
106
108
109
110
111
112
113
114
115
116
117 118
119
120
121
122
123
124
125
126
127
128
129 130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
161
151
152
153
154
155
156
157
158
159
160

162
163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181
182
184
185
186
187
188
189
190
191
192
193
17 183
204
195
196
197
198
199
200
201
202
203
18 194
205
206
207
208
209
210
211
212
213
214 215
19
20
216
217
218
219
220
221
222
223
224
225
228
229
230
231
232
233
234
235
236
21 226 227
238
239
240
241
242
243
244
245
246
247
22 237
258
248
249
250
251
252
253
254
255
256
257
23
24
259
260
261
262
263
264
265
266
267
268 269
15
16

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311 312
313
314
315
316
317
318
319
320
321
322
29
323
324
325
326
327
328
329
330
331
332
333
30
335
336
337
338
339
340
341
342
343
344
31 334
25
26
27
28

280

FEXTR symbol

T1535350-00

NEXTR symbol

Figure Q.17/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Downstream- 37 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

10

1

11

12

13

14

15

16

17

18

19

20

2

22

23

24

25

26

27

28

29

30

31

3 32
4 43
5

33

34

44

54

35

45

55

6

65

7 75
8 86

76

56

66

57

77
98

99

108

109

110

23
24

83

93

103

113

63

73
84

94

104

114

64

74
85

95

105

115

96
107

106

116

117

118

122

123

124

125

126

127

128

132

133

134

135

136

137

138

139

142

143

153

144

154

164

145

155

165

146

156

166

147

157

167

148

158

168

149

159

169

150
161

160

170

171

172

174

175

176

177

178

179

180

181

182

184

185

186

187

188

189

190

191

192

193
204

195

196

206

216

197

207

217

198

208

218

199

209

219

200

210

220

201

211

221

202

212

222

203

213

223

215

214

224

225

227

228

229

230

231

232

233

234

235

236

238

239

240

241

242

243

244

245

246

247

248

249

259

25

82

92

102

112

62

72

53

121

163

205

21 22622 239

81

91

101

111

61

71

42

52

173

17 18318 194
19
20

80

41

51

131
152

162

15
16

60

70

90

40

50

120

141

140
151

59

79
100

39

49

69

89

97

14

58

78

9

38

48

68

88

10

13

37

47

67

87

119
11
12 129 130

36

46

21

250

260

270

251

261

271

252

262

272

253

263

273

254

264

274

255

265

275

256

266

276

277

258

257

267

268

278

269

279

281
282
283
284
285
286
287
288
289
290
26 280
292
293
294
295
296
297
298
299
300
301
27 291
28
302
303
304
305
306
307
308
309
310
311
312
29
30 32331 334

313

314

324
335

315

325
336

316

326
337

317

327

318

328

338

339

319

329
340

320

330
341

321

331
342

322

332
343

333
344
T1535360-00

FEXTC symbol
NEXTC symbol

Figure Q.18/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Upstream

Q.7.2

Handshake – Non-standard information block (new)This section defines the format of the G.994.1 non-standard information block to support Annex Q, and tabulates theparameters used by Annex Q. The use of these parameters is described in §Q.7.3 and §Q.7.4.
Q.7.2.1 Non-standard information block format (new)Figure Q.19 defines the format of the non-standard information block.

- 38 -

8

7

6

5

4

3

2

1

Non-standard information length = M + 6(1 octet)
T.35 country code
(2 octets – see Note 1)
Provider code (vendor identification)(4 octets – see Note 2)
Vendor-specific information(M octets – Note 3)
NOTE 1 – The value of this field shall be B5 00, the country code for USA
NOTE 2 – The value of this field shall be 43 45 4E 54, ASCII “CENT” for Centillium
Communications
NOTE 3 – These octets are defined in §Q.7.2.2. Formatting of these octets shall comply with theparsing rules defined in G.994.1 §9.2.1 to §9.2.3

Figure Q.19 – Non-standard information block format

Q.7.2.2 Non-standard information block parameters (new)The G.994.1 non-standard parameters for Annex Q are listed in Tables Q.5 to Q.6.2.1.2.5 below.

Table Q.5 – Non-standard information field – NPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Reserved for future use

x

x

x

x

x

x

1

x

Reserved for future use

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet

NPar(1)sTable Q.6 – Non-standard information field – SPar(1) coding
Bits
8

7

6

5

4

3

2

1

SPar(1)s

x

x

x

x

x

x

x

1

G.992.1 Annex Q

x

x

x

x

x

x

1

x

Reserved for future use

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet- 39 -

Table Q.6.1 – Non-standard information field – G.992.1 Annex Q NPar(2) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

nC-PILOT1 = 64

x

x

x

x

x

x

1

x

nC-PILOT1 = 128

x

x

x

x

x

1

x

x

nC-PILOT1 = 256

x

x

x

x

1

x

x

x

Amateur radio notch – 1.8 MHz band

G.992.1 Annex Q NPar(2)s

x

x

x

1

x

x

x

x

Amateur radio notch – 3.5 MHz band

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet

Table Q.6.2 – Non-standard information field – G.992.1 Annex Q SPar(2) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Additional inband spectral shaping

x

x

x

x

x

x

1

x

Reserved for future use

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex Q SPar(2)s

Table Q.6.2.1 – Non-standard information field – G.992.1 Annex Q Npar(3) coding
Octet 1
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

x

x

x

G.992.1 Annex Q Npar(3)s Octet 1
NOMINAL_PSD_lowband (bits 8 & 7)
Reserved for future use

Table Q.6.2.1.1 – Non-standard information field – G.992.1 Annex Q Npar(3) coding
Octet 2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

x

- 40 -

G.992.1 Annex Q Npar(3)s Octet 2
NOMINAL_PSD_lowband (bits 6 to 1)

Table Q.6.2.1.2 – Non-standard information field – G.992.1 Annex Q Npar(3) coding
Octet 3
Bits
8

7

x

x

x

x

6

5

4

3

x

x

x

x

2

1

x

x

G.992.1 Annex Q Npar(3)s Octet 3
PSD level at 1622 kHz (bits 8 & 7)
Reserved for future use

Table Q.6.2.1.3 – Non-standard information field – G.992.1 Annex Q Npar(3) coding
Octet 4
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

x

G.992.1 Annex Q Npar(3)s Octet 4
PSD level at 1622 kHz (bits 6 to 1)

Table Q.6.2.1.4 – Non-standard information field – G.992.1 Annex Q Npar(3) coding
Octet 5
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

x

x

x

G.992.1 Annex Q Npar(3)s Octet 5
PSD level at 3750 kHz (bits 8 & 7)
Reserved for future use

Table Q.6.2.1.5 – Non-standard information field – G.992.1 Annex Q Npar(3) coding
Octet 6
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

x

Q.7.3

G.992.1 Annex Q Npar(3)s Octet 6
PSD level at 3750 kHz (bits 6 to 1)

Handshake – Parameter definitions (supplements 10.2)

Q.7.3.1 Handshake – ATU-C (supplements 10.2)
Q.7.3.1.1

CL messages (supplements 10.2.1)

See Table Q.7.

Table Q.7/G.992.1 – ATU-C CL message NPar(2) bit definitions for Annex Q
NSF parameter

Definition- 41 -

G.992.1 Annex Q
nC-PILOT1=64
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_
lowband
PSD level at 1622
kHz

PSD level at 3750
kHz

Q.7.3.1.2

If set to ONE, this Spar(1) bit indicates that the ATU-C is configured to support G.992.1
Annex Q.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 256.
If set to ONE, this Npar(2) bit indicates that the ATU-C is configured to reduce its transmit
power between 1.81 and 2.0 MHz to ≤ –80 dBm.
If set to ONE, this Npar(2) bit indicates that the ATU-C is configured to reduce its transmit
power between 3.5 and 3.8 MHz to ≤ –80 dBm.
If set to ONE, this Spar(2) bit indicates that the ATU-C is configured to apply additional
downstream inband spectral shaping as defined by the values of REDUCED_PSD_lowband,
PSD level at 1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C isconfigured to use in the passband below 1104 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C isconfigured to use at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C isconfigured to use at 3750 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 3750 kHz.

MS messages (supplements 10.2.2)

See Table Q.8.

Table Q.8/G.992.1 – ATU-C MS message NPar(2) bit definitions for Annex Q
NSF bitG.992.1 Annex Q
nC-PILOT1=64
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band

Definition

If set to ONE, this Spar(1) bit indicates that the ATU-C is selecting G.992.1 Annex Q.
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 256 (Note 1).
If set to ONE, this Npar(2) bit indicates that the ATU-C shall reduce its transmit power
between 1.81 and 2.0 MHz to ≤ –80 dBm.
If set to ONE, this Npar(2) bit indicates that the ATU-C shall reduce its transmit power
between 3.5 and 3.8 MHz to ≤ –80 dBm.

- 42 -

Additional inband
spectral shaping

If set to ONE, this Spar(2) bit indicates that the ATU-C shall apply additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
REDUCED_PSD This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C_lowbandshall apply in the passband below 1104 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz.
PSD level at 1622 This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
kHz
shall apply at 1622 kHz. It is coded in steps of 0.125dB relative to NOMINAL_PSD_lowband(–40dBm/Hz). For example, 00000000 means –40 dBm/Hz; 00001101 means -41.625
dBm/Hz. The PSD level shall be linearly interpolated in dBs between the
REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
PSD level at 3750 This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
kHz
shall apply at 3750 kHz. It is coded in steps of 0.125dB relative to NOMINAL_PSD_lowband(–40dBm/Hz). For example, 00000000 means –40 dBm/Hz; 00001101 means -41.625
dBm/Hz. The PSD level shall be linearly interpolated in dBs between the PSD level at 1622
kHz and the PSD level at 3750 kHz.
Note 1: One and only one pilot tone bit shall be set in an MS message.

Q.7.3.2 Handshake – ATU-R (supplements 10.3)
Q.7.3.2.1

CLR messages (supplements 10.3.1)

See Table Q.9.

Table Q.9/G.992.1 – ATU-R CLR message NPar(2) bit definitions for Annex Q
NSF bitG.992.1 Annex Q
nC-PILOT1=64
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_lowband
PSD level at 1622
kHz

Definition

If set to ONE, this Spar(1) bit indicates that the ATU-R is configured to support G.992.1
Annex Q.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 256.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports the 1.8 MHz
Amateur radio band notch.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports the 3.5 MHz
Amateur radio band notch.
If set to ONE, this Spar(2) bit indicates that the ATU-R wishes to have additional downstream
inband spectral shaping applied as defined by the values of REDUCED_PSD_lowband, PSD
level at 1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.

- 43 -

PSD level at 3750
kHz

Q.7.3.2.2

This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 3750 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 3750 kHz.

MS messages (supplements 10.3.2)

Table Q.10.

Table Q.10/G.992.1 – ATU-R MS message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q
nC-PILOT1=64

If set to ONE, this Spar(1) bit indicates that the ATU-R is selecting G.992.1 Annex Q.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.

nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping

This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.

If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
REDUCED_PSD This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R_lowbandwishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
PSD level at 1622 This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
kHz
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
PSD level at 3750 This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
kHz
wishes to have applied at 3750 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 3750 kHz.
Note 1: One and only one pilot tone bit shall be set in an MS message.

- 44 -

Q.7.3.2.3

MP messages (new)Table Q.11.
Table Q.11/G.992.1 – ATU-R MS message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q
nC-PILOT1=64

If set to ONE, this Spar(1) bit indicates that the ATU-R is proposing G.992.1 Annex Q.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.

nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping

This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.

If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
REDUCED_PSD_ This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
lowbandwishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
PSD level at 1622
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
kHz
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
PSD level at 3750
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
kHz
wishes to have applied at 3750 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 3750 kHz.
Note 1: More than one pilot tone bit may be set in an MP message.

Q.7.4

Transceiver Training – ATU-C (supplements 10.4)

During transceiver training from C-REVERB1 to C-SEGUE1 except C-PILOTn and C-QUIETn, the ATU-C shalltransmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), and shall not transmit
the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state isdefined as Figure Q.24.
Q.7.4.1

C-PILOT1 (supplements 10.4.2)

The ATU-C shall start the NSWF (sliding window frame) counter from 0 immediately after entering C-PILOT1, andincrement the NSWF counter modulo 345 after transmission of each DMT symbol. According to the sliding windowfunction and this counter, the ATU-C decides to transmit all of the subsequent symbols in either FEXTR or NEXTR
symbols (for example, see Figures Q.11, Q.17 and Q.22).
C-PILOT1 has two signals.

- 45 -

The first signal is the pilot tone, a single frequency sinusoid at fC-PILOT1 defined as:⎧
Xk = ⎨⎩

0, k ≠ nC − PILOT 1 , 0 ≤ k ≤ NSC
AC − PILOT 1 , k = nC − PILOT 1

The frequency of the pilot tone shall be selected from one of the following choices during G.994.1 as:
1. fC-PILOT1 = 276 kHz (nC-PILOT1 = 64).
2. fC-PILOT1 = 552 kHz (nC-PILOT1 = 128).
3. fC-PILOT1 = 1104 kHz (nC-PILOT1 = 256).
The second signal is the TTR indication signal used to transmit NEXTR/FEXTR information. The ATU-R can detect
the phase information of the TTRC from this signal. The TTR indication signal shall be selected during G.994.1 as:
A48 signal –the constellation encoding of the 48th carrier with 2-bit constellation as follows:(+ , +) to indicate a FEXTR symbol;(+ , –) to indicate a NEXTR symbol.
Q.7.4.2

C-PILOT1A (supplements 10.4.3)

C-PILOT1A has two signals and it is the same transmitted signal as C-PILOT1 (C.7.4.1).
Q.7.4.3

C-REVERB3 (supplements 10.4.11)

In order to synchronize the first symbol of C-RATES1 with the beginning of the hyperframe and to inform the enteringtiming of C-RATES1 to the ATU-R, the first symbol of C-SEGUE1 shall be transmitted inside of the FEXTR duration
as shown in Figure Q.20. Therefore, the duration of C-REVERB3 is 3628 DMT symbols.

TTRC
20 symbols
C-SEGUE1

C-REVERB3

C-RATES1

the time of the detection
C-SEGUE1

R-REVERB3
T1532880-99

Figure Q.20/G.992.1 – Timing diagram from C-SEGUE1 to C-RATES1

Q.7.4.4 C-REVERB1 (replaces 10.4.5)
C-REVERB1 is a signal that allows the ATU-C and ATU-R receiver to adjust its automatic gain control (AGC) to an
appropriate level. The data pattern used in C-REVERB1 shall be the pseudo-random downstream sequence (PRD), dn
for n = 1 to 2*NSC, defined in Q.4.7.5 and repeated here for convenience:dn = 1dn = dn-4 ⊕ dn-9

for n = 1 to 9
for n = 10 to 2*NSC- 46 -(10-1)

The bits shall be used as follows: the first pair of bits (d1 and d2) is used for the DC and Nyquist subcarriers (the powerassigned to them is, of course, zero, so the bits are effectively ignored); then the first and second bits of subsequentpairs are used to define the Xi and Yi for i = 1 to NSC-1 as defined in Table 7-13.
The period of PRD is only 511 bits, so dn+511 is equal to dn. The bits d1 to d9 shall be re-initialized for each symbol,
so each symbol of C-REVERB1 is identical.
The two bits that modulate the pilot carrier shall be overwritten by {0,0}: generating the {+,+} constellation.
The duration of C-REVERB1 is 512 (repeating) symbols without cyclic prefix.
Q.7.5

Transceiver Training – ATU-R (supplements 10.5)

During transceiver training from R-REVERB1 to R-SEGUE1 except R-QUIETn, the ATU-R shall transmit both
FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC
symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is defined as Figure Q.24.
Q.7.5.1

R-QUIET2 (supplements 10.5.1)

The ATU-R enters R-REVERB1 after it completes timing recovery and Hyperframe synchronization from
C-PILOT1/C-PILOT1A.
Q.7.5.2

R-REVERB1 (supplements 10.5.2)

The data pattern used in R-REVERB1 is the pseudo-random upstream sequence PRU defined in 8.11.3 and repeatedhere for convenience:⎧⎪d n = 1⎨⎪⎩d n = d n −5

for n = 1 to 6
⊕ d n − 6 for n = 7 to 64(C.10-1)

The ATU-R shall start its NSWF counter immediately after entering R-REVERB1, and then increment the NSWF
counter with modulo 345 from 0 when it transmits each DMT symbol. The ATU-C and ATU-R shall have the samevalue since hyperframe alignment between the ATU-C and ATU-R shall be maintained. According to the sliding
window and this counter, the ATU-R decides to transmit all of the subsequent symbols in either the FEXTC or the
NEXTC symbol.
Q.7.5.3

R-QUIET3 (replaces 10.5.3)

The final symbol of R-QUIET3 accommodates the frame alignment of the transmitter to that of the receiver. It may be
shortened by any number of samples. The maximum duration of R-QUIET3 is 6145 DMT symbols.
Q.7.5.4

R-REVERB2 (supplements 10.5.5)

After ATU-R detects C-SEGUE1, the ATU-R enters R-SEGUE1. The maximum duration of R-REVERB2 is 3643
DMT symbols.
Q.7.6

Channel analysis (ATU-C) (supplements 10.6)

ATU-C shall transmit only FEXTR symbols, and shall not transmit the NEXTR symbols except the pilot tone from
C-RATES1 to C-CRC2. During C-MEDLEY, the ATU-C shall transmit both FEXTR and NEXTR symbols when
Bitmap-NR is enabled (Dual Bitmap mode). The ATU-C shall not transmit NEXTR symbols except the pilot tone,
when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state is defined in Figure Q.24.
Q.7.6.1

C-SEGUE1 (supplements 10.6.1)- 47 -

The duration of C-SEGUE1 is 20 symbols in order that the first symbol of C-SEGUE1 shall be inside of the FEXTR
duration.
Q.7.6.2

C-MEDLEY (replaces 10.6.6)

C-MEDLEY is a wideband pseudo-random signal used for estimation at the ATU-R of the downstream SNR. The data
to be transmitted are derived from the pseudo-random sequence, PRD, and modulated as defined in 10.4.5. In contrast
to C-REVERB1, however, the cyclic prefix is used and the data sequence continues from one symbol to the next (i.e. d1
to d9 are not re-initialized for each symbol); since PRD is of length 511, and 2*NSC bits are used for each symbol, thesubcarrier vector for C-MEDLEY therefore changes from one symbol period to the next. The pilot subcarrier isoverwritten by the (+,+) signal constellation. C-MEDLEY is transmitted for 16 384 symbol periods. Following
C-MEDLEY the ATU-C shall enter the state C-REVERB4.
Basically, the definition of C-MEDLEY is as given above, except for the duration of the SNR estimation at ATU-R for
the downstream. With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure
Q.21. The ATU-C transmits the signal in both of NEXTR and FEXTR symbols, and the ATU-R estimates two SNRs
from the received NEXTR and FEXTR symbols, respectively, as defined in Figure Q.22.
The following formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > d) }if { (S > b) and (S + 271 < c) }where a = 1243, b = 1403, c = 2613, d = 2704

then symbol for estimation of FEXTR SNR
then symbol for estimation of NEXTR SNR

When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbol. The
number of bits of NEXTR shall be no more than the number of bits of FEXTR.
NOTE -At the transmitter, the PRD sequence generator is either always updated or always stopped during
NEXTR symbol when Bitmap-NR is disabled (FEXT Bitmap mode). The receiver should be able tosupport both modes of transmitter operation.

- 48 -TTR
TCM-ISDN crosstalkat ATU-R receiver

TCM-ISDN crosstalkat ATU-C receiver

NEXT

NEXT

FEXT

FEXT

FEXT

NEXT

NEXT

NEXT

FEXT

FEXT
Estimation of
Signal-to-Noise ratio

C/R-MEDLEY (49152 symbols)

Bitmap for Downstream

Bitmap-NR

Bitmap-FR

Bitmap-FR

Bitmap-NR

Bitmap for Upstream

Bitmap-FC

Bitmap-NC

Bitmap-NC

Bitmap-FC
T1532890-99

Figure Q.21/G.992.1 – Estimation of periodic Signal-to-Noise Ratio- 49 -

TTRC
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

4
5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

101

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

137

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

17
18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

206

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

243

24

244

245

246

247

248

249

250

251

252

253

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

275

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

315

316

317

318

319

320

321

322

323

324

31

314

32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

Symbol for estimation of FEXTR S/N
Symbol for estimation of NEXTR S/N

Symbol not used for S/N estimation
T1535370-00

Figure Q.22/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Downstream

Q.7.6.3

C-RATES1 (supplements 10.6.2)

In order to support data rates greater than 32 Mbit/s, the BI field has 11 bits. The RRSI fields shall use the same
extended syntax as defined in Q.7.9.4 for C-RATES-RA.

- 50 -

For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7.6.4

C-MSG1 (supplements 10.6.4)

Table Q.12/G.992.1 – Assignment of 48 bits of C-MSG1
Suffix(ces) of mi (Note 1)
Parameter (Note 3)
47-44
Minimum required downstream SNR margin at initialization (Note 2)
43-18
Reserved for future use
17
Trellis coding option
16
Overlapped spectrum option (Note 4)
15
Unused (shall be set to "1")
14-12
Reserved for future use
11
NTR
10-9
Framing mode
8-6
Transmit PSD during initialization
5
Reserved
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – A positive number of dB; binary coded 0-15 dB.
NOTE 3 – All reserved bits shall be set to "0".
NOTE 4 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
Q.7.6.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.6.4.8)

The Ndownmax (transmit) capability shall be binary encoded onto {m4, ..., m0} (e.g. 100012 = 17). The maximum
number of bits for the upstream data, Nupmax, that the ATU-C receiver can support need not be signalled to the ATU-R;
it will be implicit in the bits and gains message, C-B&G, which is transmitted after channel analysis.
Q.7.7

Channel analysis (ATU-R) (supplements 10.7)

From R-RATES1 to R-CRC2, the ATU-R shall transmit only the FEXTC symbols and shall not transmit the NEXTC
symbols. In R-SEGUE2 and R-MEDLEY, the ATU-R shall transmit both FEXTC and NEXTC symbols when
Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC symbols when Bitmap-NC is disabled(FEXT Bitmap mode). The duration of each state is defined in Figure Q.24.
Q.7.8

R-SEGUE1 (supplements 10.7.1)

The maximum duration of R-SEGUE1 is 14 symbols (see Figure Q.20).
Q.7.8.1

R-REVERB3 (supplements 10.7.2)

The ATU-R shall start R-REVERB3 aligned with the beginning of a Hyperframe.
Q.7.8.2

R-SEGUE2 (supplements 10.7.3)

The duration of R-SEGUE2 is 13 symbols.
Q.7.8.3

R-MEDLEY (supplements 10.7.8)

Basically, the definition of R-MEDLEY is the same as 10.7.8, except for the duration of the SNR estimation at ATU-C
for the upstream. With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure
Q.21. ATU-R shall transmit the signal in both of NEXTC and FEXTC symbols, and ATU-C shall estimate two SNRs
from the received NEXTC and FEXTC symbols, respectively, as defined in Figure Q.23.
The following numerical formula gives the information that received Ndmt-th DMT symbol belongs to:- 51 -

For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > b) and (S + 271 < c) }if { (S + 271 < a) }where a = 1148, b = 1315, c = 2608

then symbol for estimation of FEXTC SNR
then symbol for estimation of NEXTC SNRWhen Bitmap-NC is disabled (FEXT Bitmap mode), the ATU-R shall not transmit NEXTC symbol. The number of bitsof NEXTC shall be no more than the number of bits of FEXTC.
NOTE -At the transmitter, the PRD sequence generator is either always updated or always stopped during
NEXTR symbol when Bitmap-NR is disabled (FEXT Bitmap mode). The receiver should be able tosupport both modes of transmitter operation.

- 52 -

TTR R
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

101

10

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

11
12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

137

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

172

17

173

174

175

176

177

178

179

180

181

182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

206

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

243

24

244

245

246

247

248

249

250

251

252

253

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

275

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

T1535290-00

Symbol for estimation of FEXT C S/N

Symbol not used for S/N estimation

Symbol for estimation of NEXT C S/N

Figure Q.23/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Upstream- 53 -

Q.7.8.4

R-MSG1 (supplements 10.7.6)

Table Q.13/G.992.1 – Assignment of 48 bits of R-MSG1
Parameter (Note 2)
Suffix(ces) of mi (Note 1)
47-18
Reserved for future use

17
Trellis coding option
16
Overlapped spectrum option (Note 3)
15
Unused (shall be set to "1")14
Support of S = 1/2 mode (see Q.4.9) (Note 4)
13
Support of dual latency downstream
12
Support of dual latency upstream
11
Network Timing Reference
10, 9
Framing mode
8-5
Reserved for future use
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
NOTE 3 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
NOTE 4 – Since the S=1/2 mode is mandatory for Annex Q, a modem supporting Annex Q shall set this bit to binaryONE.

Q.7.8.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.7.6.6)

The Nupmax (transmit) capability is encoded onto {m4 , ..., m0} with a conventional binary representation (e.g.
100012 = 17).
Q.7.9

Exchange – ATU-C (supplements 10.8)

During C-RATESn, C-MSGn, C-B&G, and C-CRCn, the ATU-C shall transmit the FEXTR symbol. In the other signals,
the ATU-C shall transmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), andshall not transmit the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The
duration of each state is defined in Figure Q.25.
Q.7.9.1

C-MSG2 (supplements 10.8.9)

n1C-MSG2 = 43
n2C-MSG2 = 91
Q.7.9.1.1

Total number of bits per symbol supported (supplements 10.8.9.3)

The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTC and
NEXTC downstream channel performance (e.g. if the maximum numbers of bits that can be supported in FEXTC and
NEXTC symbols are 111 and 88 {Total number of bits per symbol supported} = (111 x 126 + 88 x 214)/340 = 96).
NOTE – The number of symbols per hyperframe is 340. The number of FEXT symbols is 126. The number of NEXTsymbols is 214.
Q.7.9.2

C-B&G (replaces 10.8.13)- 54 -

C-B&G shall be used to transmit to the ATU-R the bits and gains information, Bitmap-FC {b1, g1, b2, g2, ... b31, g31},
and Bitmap-NC {b33, g33, b34, g34, ..., b63, g63}, that are to be used on the upstream carriers. bi of Bitmap-FC
indicates the number of bits to be coded by ATU-R transmitter onto the i th upstream carrier in FEXTC symbols; gi ofBitmap-FC indicates the scale factor, relative to the gain that was used for that carrier during the transmission of
R-MEDLEY, that shall be applied to the i th upstream carrier in FEXTC symbols. Similarly, bi of Bitmap-NC indicatesthe number of bits onto the (i – 32) th upstream carrier in NEXTC symbols; gi of Bitmap-NC indicates the scale factor
that shall be applied to the (i – 32) th upstream carrier in NEXTC symbols.
Because no bits or energy will be transmitted at DC or one-half the sampling rate, b0, g0, b32, g32, b64, and g64 are allpresumed to be zero and shall not be transmitted.
Each bi shall be represented as an unsigned 5-bit integer, with valid bis lying in the range of zero to Nupmax, themaximum number of bits that the ATU-R is prepared to modulate onto any subcarrier, which is communicated in
R-MSG1.
Each gi shall be represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of
the third most significant bit. For example, a gi with binary representation (most significant bit listed first)
001.010000002 would instruct the ATU-R to scale the constellation for carrier i, by a gain factor of 1.25, so that thepower in that carrier shall be 1.94 dB higher than it was during R-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
The C-B&G information shall be mapped in a 992-bit (124 byte) message m defined by:
m = {m991, m990, …, m1, m0} = { g63, b63, …, g33, b33, g31, b31, …, g1, b1},

(C.10-2)

with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in
124 symbols, using the transmission method as described in 10.8.9.
When Bitmap-NC is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NC shall be set to zero.
Q.7.9.3

C-SEGUE3 (replaces 10.8.16)

The duration of C-SEGUE3 is 18 symbols. Following C-SEGUE3, the ATU-C completes the initialization and enters
C-SHOWTIME. In C-SHOWTIME, ATU-C shall transmit the signal using Bitmap-FR and Bitmap-NR with the sliding
window.
When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbols.

- 55 -

Q.7.9.4

C-RATES-RA (supplements 10.8.3)
Table Q.14/G.992.1 – RRSI fields of C-RATES-RA←⎯⎯⎯⎯⎯ bits ⎯⎯⎯⎯→
fields7

6

RSF

B10 (AS0)

0

5

4

3

2

1

value of RSF
MSB

RSI

B8 (AS0)LSB

B9 (AS0)

value of RSI
MSB

S

I9

LSB

I8

value of S
MSB

I

I7

I6

FS(LS2)

0

I5

LSB
I4

I3

I2

I1

I0

value of FS(LS2) set to {000000002}

The RSI field has been extended to include bit B9 of BI (AS0) in bit 6, and The RSF field has been extended to include
the most significant bit B10 of BI (AS0) in bit 7, BI (AS0) being the number of payload bytes in the AS0 bearer channel
in the downstream interleave buffer. This is to support the higher data rates for the S=1/4, S=1/6 and S=1/8 modes.
The S field shall be coded {1001002) to indicate S=1/4, {1001102} to indicate S=1/6, and {1010002) to indicate S=1/8.
For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7.10Exchange – ATU-R (supplements 10.9)

ATU-R shall transmit only the FEXTC symbols in R-MSGn, R-RATESn, R-B&G, R-CRCn. In other signals, the
ATU-R shall transmit both FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shallnot transmit NEXTC symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is definedin Figure Q.25.
Q.7.10.1

R-MSG-RA (supplements 10.9.2)

Replace Table 10-15 with Table Q.15.

- 56 -

Table Q.15/G.992.1 – Assignment of 80 bits of R-MSG-RA (Annex Q)
Suffix(ces) of mi(Note)
79-72
71 - 70
69, 68
67-56

Parameter
All reserved bits shall be set to 0
Reserved for ITU-T
Extension to number of RS payload bytes, K
Extension to number of tones carrying data (ncloaded)
Bfast-max

55-49
48-40
39-32
31-25
24-21
20-16

Number of RS overhead bytes, (R)
Number of RS payload bytes, K
Number of tones carrying data (ncloaded)
Estimated average loop attenuation
Coding gain
Performance margin with selected rate option

15 - 14

Extension to total number of bits per DMT symbol, Bmax

13-12
11-0

Maximum Interleave Depth
Total number of bits per DMT symbol, Bmax

NOTE – Within the separate fields the least significant bits have the lowest subscripts.

Q.7.10.1.1

Total number of bits supported (Bmax) (replaces 10.9.2.8)

This parameter shall be defined as in R-MSG2, see Q.7.9.1.
Q.7.10.1.2

Bfast-max (new)Bfast-max is the maximum number of bits of the fast buffer for fast data transmitted on the condition that the bits of thefast data can be equally assigned to all FEXT-symbols and NEXT-symbols.
Fast Buffered Data Bfast-max is tf.
Q.7.10.2

R-MSG2 ( supplements 10.9.8)

Table Q.16/G.992.1 – Assignment of 32 bits of R-MSG2
Suffix(ces) of mi (Note 1)
Parameter (Note 2)
31-25
Estimated average loop attenuation
24-21
Reserved for future use
20-16
Performance margin with selected rate option
15 - 14
13-12
11-0

Extension to total number of bits per DMT symbol, Bmax
Reserved for future use
Total number of bits per DMT symbol, Bmax

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
N1R-MSG2 = 10
N2R-MSG2 = 20
Q.7.10.2.1

Total number of bits per symbol supported (supplements 10.9.8.3)

The maximum number of bits per symbol that the downstream channel can support is encoded into bits 15, 14 and 11 –0.

- 57 -

The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTR and
NEXTR downstream channel performance. For example, if the maximum numbers of bits that can be supported in
FEXTR and NEXTR symbols are 111 and 88, the total number of bits per symbol supported is (111 x 126 + 88 x
214)/340 = 96.
NOTE – The number of symbols per hyperframe is 340, the number of FEXT symbols is 126, and the number of NEXTsymbols is 214.
Q.7.10.3

R-B&G (replaces 10.9.14)

The purpose of R-B&G is to transmit to ATU-C the bits and gains information, Bitmap-FR {b1, g1, b2, g2, ..., bNSC-1,
gNSC-1}, and Bitmap-NR {bNSC+1, gNSC+1, bNSC+2, gNSC+2, ..., b2*NSC-1, g2*NSC-1}, to be used on thedownstream subcarriers. bi of Bitmap-FR indicates the number of bits to be coded by ATU-C transmitter onto the i th
downstream subcarrier in FEXTR symbols; gi of Bitmap-FR indicates the scale factor that shall be applied to the i th
downstream subcarrier in FEXTR symbols, relative to the gain that was used for that carrier during the transmission of
C-MEDLEY. Similarly, bi of Bitmap-NR indicates the number of bits onto the (i – NSC) th downstream carrier in
NEXTR symbols; gi of Bitmap-NR indicates the scale factor that shall be applied to the (i – NSC) th downstream
carrier in NEXTR symbols. Because no bits or energy will be transmitted at DC or one-half the sampling rate, b0, g0,
bNSC, gNSC, b2*NSC, and g2*NSC are all presumed to be zero, and are not transmitted. When subcarrier 64 isreserved as the pilot tone, b64 and bNSC+64, shall be set to 0, g64 and gNSC+64 shall be set to gsync. When subcarrier
128 is reserved as the pilot tone, b128 and bNSC+128, shall be set to 0, g128 and gNSC+128 shall be set to gsync. The
value gsync represents the gain scaling applied to the sync symbol.
Each bi is represented as an unsigned 5-bit integer, with valid bi lying in the range of zero to Ndownmax, the maximum
number of bits that the ATU-C is prepared to modulate onto any subcarrier, which is communicated in C-MSG1.
Each gi is represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of thethird most significant bit. For example, a gi with binary representation (most significant bit listed first) 001.010000002
would instruct the ATU-C to scale the constellation for carrier i by a gain factor of 1.25, so that the power in that carrier
shall be 1.94 dB higher than it was during C-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
The R-B&G information shall be mapped in a (2*NSC-2)*16-bit ((2*NSC-2)*2 byte) message m defined by:
m = {m(2*NSC-2)*16-1, m(2*NSC-2)*16-2, …, m1, m0} = { g2*NSC-1, b2*NSC-1, …, g NSC+1, b NSC+1, g(Q.10-3)
NSC-1, b NSC-1, …, g1, b1},
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in(2*NSC-2)*2 symbols, using the transmission method as described in 10.9.8.
When Bitmap-NR is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NR shall be set to zero.
Q.7.10.4

R-SEGUE5 (replaces 10.9.17)

The duration of R-SEGUE5 is 13 symbols. Following R-SEGUE-5, ATU-R completes the initialization and enters
R-SHOWTIME. In R-SHOWTIME, ATU-R shall transmit the signal using Bitmap-FC and Bitmap-NC with the sliding
window.
When Bitmap-NC is disabled (FEXT Bitmap mode), ATU-R shall not transmit NEXTC symbols.

- 58 -

ATU-CC-FLAG2(G.994.1)

C-GALF2(G.994.1)≥ 128≤ 2048C-QUIET2(Note 5)345n(n ≤ 38)

ATU-R

If R-ACK2then
C-PILOT1

If R-ACK1then
C-PILOT1AR-GALF2(G.994.1)

Beginning ofHyperframe

R-QUIET2≤ 15500

345n(1 ≤ n ≤ 33)≤ 32
Beginning ofHyperframe

1725

C-QUIET3A(Note 2)

R-FLAG2(G.994.1)

R-REVERB1
1536

C-REVERB1
12477(Note 5)9216

C-PILOT2(Note 4)

1536

C-ECT

(Note 2)

(Note 5)4608

C-REVERB2

1536

If R-ACK2 then C-PILOT3
If R-ACK1 then C-QUIET53628

C-REVERB3

20

C-SEGUE1

2884

C-RATES1/C-CRC1
C-MSG1/C-CRC2

Last symbol
may beshortened byn samples

R-QUIET3≥ 6144≤ 6145

R-ECT

1536

R-REVERB2≥ 3634≤ 3643

R-SEGUE1

5 ≤, ≤ 14(Note 2)

(Note 1)Introduction ofguard time

R-REVERB3
345n + 208(0 ≤ n ≤ 7)

49152
C-MEDLEY

345n - 13(9 ≤ n ≤ 16)
R-SEGUE2

13

R-RATES1/R-CRC1
R-MSG1/R-CRC2

1254

R-MEDLEY

49152(Note 3)(Note 2)

T1532900-99

Figure Q.24/G.992.1 – Timing diagram of the initialization sequence – Part 1- 59 -(Note 4)

ATU-R

ATU-C(Note 4)R-MEDLEY

345n - 304(7 ≤ n ≤ 20)

C-REVERB4(Note 2)

R-REVERB4

296

R-SEGUE3

13

R-MSG-RA/R-CRC-RA1
R-RATES-RA/R-CRC-RA2

40(Note 3)345n + 287(0 ≤ n ≤ 6)

(Note 1)18

C-SEGUE2

347

C-RATES-RA/C-CRC-RA1
C-MSG-RA/C-CRC-RA2

R-REVERB-RA

345n - 53(3 ≤ n ≤ 16) (Note 4)345n + 330(0 ≤ n ≤ 7)
C-REVERB-RA(Note 2)345n - 20(2 ≤ n ≤ 16)

R-SEGUE-RA

13

R-MSG2/R-CRC-3
R-RATES2/R-CRC4

27

R-REVERB5

345n - 40(3 ≤ n ≤ 16)(Note 3)345n + 300(0 ≤ n ≤ 7)

(Note 1)18

C-SEGUE-RA

22

C-MSG2/C-CRC-3
C-RATES2/C-CRC4

336

C-B&G/C-CRC5C-REVERB5(Note 4)345n + 319(0 ≤ n ≤ 6)
R-SEGUE4345n - 31(10 ≤ n ≤ (NSC/32)+12)

R-B&G/R-CRC5345n + 330(0 ≤ n ≤ 4)
18

R-REVERB6

C-SEGUE3

13(Note 3)(345*NSC/32)-3

345n - 10(2 ≤ n ≤ 16)

345n + 332(0 ≤ n ≤ 10)(Note 2)

(Note 4)R-SEGUE5

SHOWTIME
Maximum
initialization time
26.9 seconds

13

SHOWTIME

T1532910-99

NOTE 1 – The ATU-C shall transmit the FEXTR symbols, and shall not transmit as NEXTR symbols except the pilot
tone.

- 60 -NOTE 2 – The ATU-C shall transmit both FEXTR and NEXTR symbols, when Bitmap-NR is enabled (Dual Bitmapmode). ATU-C shall not transmit the NEXTR symbols except pilot tone, when Bitmap-NR is disabled(FEXT Bitmap mode).
NOTE 3 – The ATU-R shall transmit the FEXTC symbols, and shall not transmit the NEXTC symbols.
NOTE 4 – The ATU-R shall transmit both FEXTC symbols, when Bitmap-NC is enabled (Dual Bitmap mode).
ATU-R shall not transmit NEXTC symbols, when Bitmap-NC is disabled (FEXT Bitmap mode).
NOTE 5 – The ATU-C shall transmit both FEXTR and NEXTR symbols.
Figure Q.25/G.992.1 – Timing diagram of the initialization sequence – Part 2

Q.8
Q.8.1.1

AOC On-line adaptation and reconfiguration (pertains to clause 11)
Bit swap request (replaces 11.2.3)

The receiver shall initiate a bit swap by sending a bit swap request to the transmitter via the AOC channel. This request
tells the transmitter which subcarriers are to be modified. The format of the request is shown in Table Q.17.

Table Q.17/G.992.1 – Format of the bit swap request message
Message header{111111112}(8 bits)

Bitmap index(1 bit)Message field 1-4
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

The request shall comprise nine bytes as follows:• an AOC message header consisting of 8 binary ones;• message fields 1-4, each of which consists of a one-bit bitmap index, subchannel index bits 10 & 9, and a five-bit
command followed by bits 8 to 1 of the subchannel index. One-bit bitmap index, subchannel index bits 10 & 9,
and valid five-bit commands for the bit swap message shall be as shown in Table Q.18. In Table Q.18, the MSB
for the bit swap request command represents the Bitmap index. For downstream data, Bitmap index equals 0
indicates Bitmap-FR, and Bitmap index equals 1 indicates Bitmap-NR. Similarly for upstream data, Bitmap
index equals 0 indicates Bitmap-FC, and 1 indicates Bitmap-NC. The next 2 bits are subchannel index bits 10 &9. The ten-bit subchannel index is counted from low to high frequencies with the lowest frequency subcarrier
having the number zero. The subcarrier index zero shall not be used;• the bit swap between FEXTC/R symbols and NEXTC/R symbols is not allowed.

- 61 -

Table Q.18/G.992.1 – Bit swap request commandValue(8 bit)yzz000002

Interpretation
Do nothing

yzz000012
yzz000102

Increase the number of allocated bits by one

yzz000112
yzz001002

Increase the transmitted power by 1 dB

yzz001012
yzz001102

Increase the transmitted power by 3 dB

yzz001112
yzz01xxx2

Reduce the transmitted power by 2 dB

Decrease the number of allocated bits by one
Increase the transmitted power by 2 dB
Reduce the transmitted power by 1 dB
Reserved for vendor discretionary commands

NOTE – y is "0" for FEXTC/R symbols, and "1" for NEXTC/R symbols of the Sliding Window.
NOTE – subchannel index = zz2*256 + subchannel index value from lower 8 bit field
The bit swap request message (i.e. header and message fields) shall be transmitted five consecutive times.
To avoid gi divergence between ATU-C and ATU-R after several bit swaps, for a gi update of ∆ dB the new gi value
should be given by:

g i ' = (1 / 256) × round (256 × g i × 10 exp(∆ / 20))
Q.8.1.2(Q.11-1)

Extended bit swap request (supplements 11.2.4)

The format of the extended bit swap request is shown in Table Q.19.

Table Q.19/G.992.1 – Format of the bit swap request message
Message header{111111002}(8 bits)

Bitmap index(1 bit)Message field 1-6
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

In the same manner as the bit swap request, each of the message fields of the extended bit swap request consists of
one-bit bitmap index, a five-bit command followed by a related ten-bit subchannel index.
Q.8.1.3

Bit swap acknowledge (supplements 11.2.5)

The bit swap superframe counter number shall only indicate the last superframe (SPF#4) of a hyperframe.
The new bit and/or transmit power table(s) shall then take effect starting from the first frame (frame 0) of SPF#0 of a
hyperframe.
If the bit swap superframe counter number contained in the received bit swap acknowledge message does not indicate
SPF#4, then the new table(s) shall take effect starting from frame 0 of SPF#0 of the next hyperframe.

- 62 -

資料２
G.992.1 ANNEX Q-EU (REVISION 3.2)
PROPRIETARY EXTENSION TO G.992.1 ANNEX I

This document defines G.992.1 Annex Q-EU (Quad spectrum downstream with extended upstream spectrum), a
proprietary extension to G.992.1 Annex I to extend the data rate beyond 32 Mbit/s downstream and 2 Mbit/s upstream
on short loops by way of:• Increased downstream bandwidth Æ increased number of subcarriers, NSCds=1024 (used subcarriers up to869)• Increase upstream bandwidth Æ increased number of subcarriers, NSCus=64• Increased bit loading, beyond 15 bits/bin• Extended framing Æ S=1/2n, with support for n = 1 to 4
Due to the increase in upstream data rates, the upstream maximum interleave depth has been increased to 16. Support ofthis is mandatory.
The attached text is the approved text for Annex I, marked up with revision control to show the changes necessary tosupport the additional functionality.
Revision R3 has the following changes with respect to Revision R2:• modified both downstream and upstream PSDs
• added support for overlapped spectrum• added G.994.1 code points to support above changes
Revision 3.2 changes the following with respect to Revision 3.1:
• changes PRD and PRU polynomial for MEDLEY (REVERB is unchanged) by defining new PRDm and PRUm.
• removes HAM band notches from the PSD definitions to allow them to be disabled.
• makes upstream masks EU-36 to EU-64 optional for use with non-overlapped spectrum as well as overlapped
spectrum, and adds associated downstream masks DS-36 to DS-60 for non-overlapped spectrum.
• added a new G.994.1 NPar(3) code point to indicate support for the optional EU masks with non-overlapped
spectrum. Changed the bit assignments for the mode 1 upstream masks and mode 2 upstream masks from
NPar(2) to NPar(3) within the extended upstream branch of the tree. Changed bit assignments for the EU-32 to
EU-64 NPar(3) code points.
• Modified timing diagram for initialization in Figure Q.27(Text in C-B&G and R-REVERB5 has been changed.
Update Figure Q.27)- 63 -

ANNEX Q-EU
Specific requirements for an ADSL system to support downstream data rates greater than 32 Mbit/s andupstream data rates greater than 2 Mbit/s on short loops operating in the same cable as ISDN as defined in
ITU-T Recommendation G.961 Appendix III

Q.1

Scope

This annex describes those specifications that are unique to an ADSL system coexisting in the same binder as
TCM-ISDN as defined Recommendation G.961 Appendix III. The subclauses in this annex provide supplementary andreplacement material to the clauses in the main body. The nature of the material is parenthetically indicated in the
subclause heading. The modifications described in this annex allow a performance improvement from the ADSL system
specified in Annex C for short loops in an environment coexisting with TCM-ISDN in the same cable. Specifically, thisAnnex specifies extensions to downstream and upstream bandwidth, framing modes, and maximum bit loading tosupport downstream data rates greater than 32 Mbit/s and upstream data rates greater than 2 Mbit/s. This annex also
defines those parameters of this ADSL system that have been left undefined in the main body of this Recommendation.
An ADSL system implementing Annex Q-EU shall support Annex Q. It is recommended that an ADSL system
implementing Annex Q-EU also implements Annexes I and C.
Q.2

Definitions

Bitmap-FC
Bitmap-FR
Bitmap-NC
Bitmap-NR
Dual Bitmap
FEXT Bitmap
FEXTC duration
FEXTC symbol
FEXTR duration
FEXTR symbol
Hyperframe
NEXTC duration
NEXTC symbol
NEXTR duration
NEXTR symbol
NSCds

NSCus
NSWF
Subframe
TTR
TTRC
TTRR
UI

ATU-R transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-R
ATU-R transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-R
The Dual Bitmap method has dual bit rates under the FEXT and NEXT noise from TCM-ISDN
Similar to the Dual Bitmap method however transmission only occurs during FEXT noise fromTCM-ISDN
TCM-ISDN FEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN FEXTTCM-ISDN FEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN FEXT
5 Superframes structure which synchronized TTR
TCM-ISDN NEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN NEXT
TCM-ISDN NEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN NEXT
The highest subcarrier index that can be used for downstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCds = 256 for a downstream
channel using the frequency band up to 1.104MHz; NSCds = 512 for a downstream channel
using the frequency band up to 2.208MHz.
The highest subcarrier index that can be used for upstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCus = 64 for an upstream
channel using the frequency band up to 276 kHz.
Sliding Window frame counter10 consecutive DMT symbols (except for sync symbols) according to TTR timing
TCM-ISDN Timing Reference
Timing reference used in ATU-C
Timing reference used in ATU-R
Unit Interval- 64 -

Q.3

Reference Models

Q.3.1

ATU-C transmitter reference model (replaces figures in 5.1)

See Figure Q.1 and Figure Q.2.
"Bits""Bits" &"Gains"
2*NSCds-1

AS0
AS1
AS2
AS3
LS0
LS1
LS2
NTR

crcf
Mux/
Sync
Control

crci

scram
&
FEC

scram
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

2*NSCds-2
480
IDFT

OutputParallel/
SerialBuffer

1
n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to NSCds-1
Constellation
Encoder Input
Data Frame

U-C

T1532760-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure Q.1/G.992.1 – ATU-C transmitter reference model for STM transport
Annex Q-EU does not currently support STM transport. It only supports ATM transport.

- 65 -

"Bits""Bits" &"Gains"
2*NSCds-1

AS0
ATM0

Cell TC
crcf

AS1
ATM1

Cell TC

NTR

Mux/
Sync
Control
crci

scram
&
FEC

scram
&
FEC

Rate
converterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

2*NSCds-2
480
IDFT
1

OutputParallel/
SerialBuffer

n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to NSCds-1
Constellation
Encoder Input
Data Frame

U-C

T1532770-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure Q.2/G.992.1 – ATU-C transmitter reference model for ATM transport- 66 -

Q.3.2

ATU-R transmitter reference model (replaces figures in 5.2)

See Figure Q.3 and Figure Q.4.

"Bits""Bits" &"Gains"LS02*NSCus-1
crcf

LS0
LS1

Mux/
Sync
ControlLS2

crci

scrambler&
FEC

scrambler
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

2*NSCus-2
59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR

B
FEC Output
Data Frame

Zi
i=1 to NSCus-1
C
Constellation
Encoder Input
Data Frame

U-R

T1532780-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (1.104 MHz).

Figure Q.3/G.992.1 – ATU-R transmitter reference model for STM transport
Annex Q-EU does not currently support STM transport. It only supports ATM transport.

- 67 -

"Bits"

2*NSCus-1

LS0
Cell TC

ATM0

LS1Cell TC

ATM1"Bits" &"Gains"

crcf
Mux/
Sync
Control
crci

scrambler&
FEC

scrambler&
FEC

2*NSCus-2

RateconverterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR
B
FEC Output
Data FrameZi
C
i=1 to NSCus-1
Constellation
Encoder Input
Data Frame

U-R

T1532790-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (1.104 MHz).

Figure Q.4/G.992.1 – ATU-R transmitter reference model for ATM transport- 68 -

Q.3.3

ATU-C/R transmitter timing model (replacement for 5.3)

Q.3.3.1

TCM-ISDN crosstalk timing model (new)Figure Q.5 shows the timing chart of the crosstalk from TCM-ISDN.

TTR
377 UI
receive ISDN

transmit ISDNCO

0 ≤ propagation delay ≤ 16 UI
RT

6-7.5 UI

377 UI

receive ISDN

transmit ISDN

FEXTR

NEXTR

SC
TTRC

ATU-C TX

Frame Frame0 ≤ propagation delay ≤ 18.5 UI

Received
TTRC

SR

TTRR
NEXTC
ATU-R TXFEXTC

Frame Frame
T1532800-99

1 UI = 3.125 µs
FEXTR and NEXTR are estimated by ATU-CFEXTC and NEXTC are estimated by ATU-R

TTR

TCM-ISDN timing reference

TTRC

Timing reference used in ATU-C

Received TTR C Received TTRC at ATU-R
TTRRTiming reference used in ATU-R

SC

55 × 0.9058 µs: Offset from TTR to TTRC

SR

–42 × 0.9058 µs: Offset from received TTRC to TTRR

Figure Q.5/G.992.1 – Timing chart of the TCM-ISDN crosstalk

The data stream of TCM-ISDN is transmitted in TTR period. CO transmits the stream in the first half of the TTR period
and RT transmits in the second half of the TTR period. ATU-C receives NEXT noise from the ISDN in the first half of
the TTR period and FEXT noise from the ISDN in the second half of the TCM-ISDN period. On the other hand,
ATU-R receives FEXT noise from the ISDN in the first half of the TTR period and NEXT noise from the ISDN in thesecond half of the TTR period.

- 69 -

As defined in Q.7.6.2 and Q.7.8.3, the ATU-C shall estimate the FEXTR and NEXTR duration at ATU-R, and the
ATU-R shall estimate FEXTC and NEXTC duration at ATU-C taking propagation delay on the subscribe line into
consideration.
The ATU-C shall transmit any symbols by synchronizing with the TTRC. The ATU-R shall transmit any symbols
synchronizing with the TTRR generated from received TTRC.
Q.3.3.2

Sliding window (new)Figure Q.6 shows the timing chart of the transmission for the Annex Q-EU downstream at ATU-C.
Hyperframe = 345 symbols

TTRC
Crosstalk
period

FEXTR

FEXTR

FEXTR

FEXTR
NEXTR

NEXTR

ATU-C
T Frame
SWB
T1532810-99

FEXTR symbol
NEXTR symbol

Sliding Window

Figure Q.6/G.992.1 – Sliding window for downstream symbols

The Sliding Window defines the transmission symbols under the crosstalk noise environment synchronized to theperiod of TTR. The FEXTC/R symbol represents the symbol completely inside the FEXTC/R duration. The NEXTC/R
symbol represents any symbol containing the NEXTC/R duration. Thus, there are more NEXTC/R symbols than
FEXTC/R symbols.
The ATU-C decides which transmission symbol is FEXTR or NEXTR symbol according to the sliding window andtransmits it with the corresponding bit table. Similarly, the ATU-R decides the transmission symbol is a FEXTC or
NEXTC and transmits it with the corresponding bit table. Although the phase of the sliding window is asynchronouswith TTRC/R, the pattern is fixed to the 345 frames of the hyperframe.
Q.3.3.3

ATU-C Symbol Synchronization to TTR (new)345 symbols are 34 cycles with cyclic prefix of TTRC (or 32 cycles of TTRC without cyclic prefix). This implies a PLL
lock at the ATU-R.
Q.3.3.4

Dual Bitmap switching (new)The ATU-C transmits FEXTR symbols using Bitmap-FR (in FEXTR duration), and transmits NEXTR symbols using
Bitmap-NR (in NEXTR duration) according to the result of initialization. The ATU-R transmits FEXTC symbols using
Bitmap-FC (in FEXTC duration), and transmits NEXTC symbols using Bitmap-NC (in NEXTC duration) in the samemanner.
The ATU-C shall have the capability to disable Bitmap-NC and Bitmap-NR (see Q.4.5 and Q.5.3).

- 70 -

Q.3.3.5

Loop timing at ATU-R (new)The phase relation between received symbol and transmitted symbol of ATU-R at the reference point U-R shall meetthe phase tolerances as shown in Figure Q.7.
(point U-R)
ATU-R receive
DMT symbol

ATU-R transmit
DMT symbol
T1532820-99±4.5 µs + SR

Figure Q.7/G.992.1 – Loop timing for ATU-R

Q.4

ATU-C functional characteristics (pertains to clause 7)

Q.4.1

STM transmission protocols specific functionality (pertains to 7.1)

Q.4.1.1

ATU-C input and output V interface for STM transport (replaces figure in 7.1.1)

See Figure Q.8.

- 71 -

AS0 (n0 × 32 kbit/s)
AS1 (n1 × 32 kbit/s)
AS2 (n2 × 32 kbit/s)
AS3 (n3 × 32 kbit/s)
Digital
Network

twisted pair

LS0 ("C"; 16 or m0 × 32 kbit/s)

ATU-C

LS1 (m1 × 32 kbit/s)
LS2 (m2 × 32 kbit/s)
NTR
TTR
Operations, maintenance and control

T1532830-99

V-C
NOTE 1 – Optional bearer channels (both duplex and simplex) and features are shown with dotted lines.
NOTE 2 – TTR may be generated in the ATU-C without being provided from the V-C reference point.

Figure Q.8/G.992.1 – ATU-C functional interfaces for STM transport at the V-C reference point

Q.4.1.2

Payload transfer delay (supplements 7.1.4)

Since Annex Q-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.1.4.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
Q.4.2
Q.4.2.1

ATM transmission protocols specific functionalities (pertains to 7.2)
ATU-C Input and Output V interface for ATM transport (replaces figure in 7.2.1)

See Figure Q.9.

- 72 -

ATM layer

ATM0
Tx_ATM0P
O
RT0

Tx_Cell_Handshake0
Rx_ATM0
Rx_Cell_Handshake0

ATM1
P
O
R
T
1

Twisted pair

Tx_ATM1
ATU-C
Tx_Cell_Handshake1
Rx_ATM1
Rx_Cell_Handshake1
NTR

and interface to
Digital network

TTR
Operations, administration,
maintenance and control
V-C

T1532840-99

NOTE – TTR can be generated in the ATU-C without being provided from the V-C reference point.

Figure Q.9/G.992.1 – ATU-C functional interfaces to the ATM layer at the V-C reference point

Q.4.2.2

Payload transfer delay (supplements 7.2.2)

Since Annex Q-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.2.2.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
Q.4.3
Q.4.3.1

Framing (pertains to 7.4)
Superframe structure (supplements 7.4.1.1)

Since the rate converter reorders the user data and overhead bit-level data to create hyperframes, the input data frames
to the constellation encoder are different than those defined in 7.4.1.1.
Q.4.3.2

Hyperframe structure (replaces 7.4.1.3)

Annex Q-EU uses the hyperframe structure shown in Figure Q.10. Figure Q.10 shows the phase relationship between
the TTRC and the hyperframe at the point U-C. Each hyperframe is composed of 5 superframes, which are numberedfrom 0 to 4. In order to indicate the boundary of the hyperframe, the inverse synch symbol is used for the 4thsuperframe (SPF#3), which is generated from a tone-by-tone 180-degree phase reversal of the synchronization symbol(see Q.4.7.1) except for the pilot tone.
The bit-level data stream from the rate-converter is extracted according to the size of Bitmap-FR and Bitmap-NR using
the Sliding Window (see Q.3.3.2).
In order to make the bit rate to be a multiple of 32 kbit/s, the dummy bits are inserted at the end of hyperframe by the- 73 -

rate converter (see Q.4.4.2). The hyperframe is composed of 345 DMT symbols, numbered from 0 to 344. Each symbol
is assigned as FEXTR or NEXTR symbol in a FEXTR or NEXTR duration (see Q.2), and the following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-C transmitter (see Figure Q.11).
For Ndmt = 0, 1, ..., 344

S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > a + b) }elsethen FEXTR symbol
then NEXTR symbol

where a = 1243, b = 1461
Thus, 128 DMT symbols are allocated in the FEXTR duration, and 217 DMT symbols are allocated in the NEXTR
duration. The symbols are composed of:
FEXTR symbol:
Number of symbol using Bitmap-FR
Number of synch symbol
Number of inverse synch symbol
NEXTR symbol:

= 126
=1
=1

Number of symbol using Bitmap-NR= 214

Number of synch symbol=3

During FEXT Bitmap mode, the ATU-C shall transmit only the pilot tone in NEXTR symbols.

- 74 -

5 Superframe (= 340 frames)(point B)
1 Superframe = 68 frames (17 ms)

1 frame = 250 µs
Rate-Converter(point U-C, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#27

TC#33

TTR
ATU-R
Crosstalk

NEXT

FEXT

FEXT

Hyperframe = 345 symbols (85 ms)

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol F F F F N N N N N N F F

SPF#1
S

Sliding window

SPF#2
S

S

SPF#3
N F I

Inverse synch symbol

S

NEXTR Synch symbol

F

Symbol using Bitmap-FR (FEXTR duration bitmap)

N

Symbol using Bitmap-NR (NEXTR duration bitmap)

S

FEXTR Synch symbol

Figure Q.10/G.992.1 – Hyperframe structure for downstream- 75 -SPF#4
F F

FEXTR duration

1 symbol = 246 µs
I

NEXT

N
T1532850-99

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

0
10
20
30

1

2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
21
22
23
24
25
26
27
28
29
40
31
32
33
34
35
36
37
38
39
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
SS
61
62
63
64
65
66
67
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100 101
101 102
103
104
105
106
107
108
109
110 111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
SS
132
133
134
135
136
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162 163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181 182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
SS
203
204
205
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233 234
235
236
237
238
239
240
241
242 243
253
244
245
246
247
248
249
250
251
252
263
254
255
256
257
258
259
260
260
262
264
265
266
267
268
269
270
271
272
273
274
276
277
278
279
280
281
282
283
ISS
284
285
286
287
288
289
290
291
292
293
295
296
297
298
299
300
301
302
303
294
304 305
306
307
308
309
310
311
312
313 314
315
316
317
318
319
320
321
322
323
324
334
325
326
327
328
329
330
331
332
333
SS
335
336
337
338
339
340
341
342
343
ISS

Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol
NEXTR data symbol

SS

NEXTR synch symbol
T1535330-00

Figure Q.11/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Downstream

Q.4.3.3

Subframe Structure (replaces 7.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table Q.1. The 34 subframes forma hyperframe.

- 76 -

Table Q.1/G.992.1 – Subframe (downstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

Q.4.3.4

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Inverse Synch Symbol#344 is Synch Symbol

Reduced overhead framing with merged fast and sync bytes (modifies 7.4.3.2)

In S=1/2n framing mode (see §Q.4.9), there are n Sync bytes per symbol time. The contents of the Sync bytes is thesame as in regular framing except that it repeats at n times the rate causing the superframe to be 68/n symbols in length.
The contents of the sync bytes are shown in Table 7-6/G.992.1. In S=1/2n framing mode, “Frame Number” in column 1
in Table 7-6/G.992.1 is replaced by “Sync Byte Index Number”.
As a result of the increase in superframe rate, the superframe contents is carried more frequently. For the case when
N=2, the EOC and AOC bandwidth doubles, thereby transferring actual messages at twice the rate. The CRC byte iscarried twice as frequently and therefore the maximum error rate rises from just over 58 per second to 117 per second.
Where the duration of an error condition is measured, this needs to be taken into consideration. The indicator bits arealso sent twice as often, which needs to be taken into consideration for statistics collection.
Q.4.4

Dual Bitmapping and Rate Conversion (replaces 7.15)

The functions of the rate converter (see Q.4.4.2), tone ordering (see Q.4.6), constellation encoding, and gain scaling
shall use one of two bitmaps stored in the ATU. This method is called the dual bitmap.

- 77 -

Q.4.4.1

Dual Bitmap (new)The Dual Bitmap method has individual bit rates under the FEXT and NEXT noise, and this needs an additional bit andgain table, {bi, gi}, and ordered bit table, b'i, for the tone ordering. The dual bitmaps are switched synchronized withthe sliding window pattern of NEXT/FEXT symbols. The number of bits and the relative gains to be used for every tone
are calculated in the bit loading algorithm during the initialization sequence, and transmitted in R-B&G.
Q.4.4.2

Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FR, Bitmap-NR and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amount of fast and interleaved data in Bitmap-FR and Bitmap-NR shall be calculated with thefollowing formulae and illustrated in Figure Q.12:
If tRf ≤ nRmax:n Rf = t Rf
nRi = nR − nRf
f Rf = t Rf
f Ri = f R − f Rf
If tRf > nRmax:

nRf = nR max

nRi = 0⎧⎡ t Rf × 10 − nRf × 6 ⎤⎪ f Rf 4 = ⎢
⎥
4
⎢
⎥
⎪
f Rf = ⎨⎡ t Rf ×10 − nRf × 7 ⎤⎪⎥⎪ f Rf 3 = ⎢3⎢⎥⎩⎧⎪ f Ri 4 = f R = f Rf 4
f Ri = ⎨⎪⎩ f Ri3 = f R − f Rf 3
Where:
tRf
tRi
fRf and nRf
fRf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FR and Bitmap-NR, respectively.
is the number of fast bits in Bitmap-FR if the subframe (see Q.4.3.3) contains 3 Bitmap-FR except
for synch symbols.
fRf4
is the number of fast bits in Bitmap-FR if the subframe contains 4 Bitmap-FR except for synch
symbols.
fRi and nRi
are the numbers of interleaved bits in Bitmap-FR and Bitmap-NR, respectively.
nR
is the number of total bits in Bitmap-NR, which is specified in the B&G tables.
During FEXT Bitmap mode, nRf and nRi are zero.
To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tRf ≤ nRmax:- 78 -

dummy Rf = 0

dummy Ri = ( f Ri × 126 + nRi × 214) − t Ri × 340

If tRf > nRmax:()
dummy Rf 3 = ( f Rf × 3 + nRf × 7 ) − t Rf × 10

dummy Rf 4 = f Rf × 4 + nRf × 6 − t Rf ×10

dummy Ri = ( f Ri 4 × 96 + f Ri3 × 30 ) − t Ri × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FR constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:

dummySRf = f Rf 3 − f Rf 4
The receiver shall determine Bitmap-FR and Bitmap-NR so that dummyRi is less than 126, dummyRf4 is less than 4 anddummyRf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.

- 79 -

#335#336#337#338#339#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25 #26 #27 #28 #29

tRi

Interleaved DatatRj

Fast Data

NOTE – Bit Ordering:
The earlier bit is located at the bottom
each symbol in this figure.
Rate Converter

Order

When tRf ≤ nRmax

fRi =fR – fRf

fR#4 #5 #6 #7 #8 #9

dummyRi#21 #22 #23#10 #11 #12 #13#0 #1 #2 #3#14 #15 #16 #17 #18 #19 #20#343#339#340#341#342#24 #25 #26 #27 #28 #29

nRinnRf=tRf R

fRf – tRf
FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe

When tRf > nRmax#0 #1 #2 #3#21 #22 #23#10 #11 #12 #13

dummyRi

fRi3

fRi4
dummyRf4

fR#335#336#337#338

dummyRf4

dummyRf3

dummy Rf4

fRf3
fRf4

#4 #5 #6 #7 #8 #9#14#15 #16 #17#18 #19 #20#26 #27 #28 #29#339#340#341#342#343

nRf = n
FEXTNEXT
Symbols Symbols
Subframe

FEXT
Symbols

NEXT
Symbols

Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe
T1532860-99

Figure Q.12/G.992.1 – Bit distribution for Rate Converter under Dual latency and Dual Bitmap mode

Q.4.5

FEXT Bitmapping (replaces 7.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (Q.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures Q.10 and Q.16).
Annex Q-EU does not support the FEXT Bitmapping mode.
Q.4.6

Tone Ordering (replacement for 7.7)

A DMT time-domain signal has a high peak-to-average ratio (its amplitude distribution is almost Gaussian), and large
values may be clipped by the digital-to-analogue converter. The error signal caused by clipping can be considered as anadditive negative impulse for the time sample that was clipped. The clipping error power is almost equally distributed
across all tones in the symbol in which clipping occurs. Clipping is therefore most likely to cause errors on those tones- 80 -

that, in anticipation of a higher received SNR, have been assigned the largest number of bits (and therefore have thedensest constellations). These occasional errors can be reliably corrected by the FEC coding if the tones with the largest
number of bits have been assigned to the interleave buffer.
The numbers of bits and the relative gains in two bitmaps to be used for every tone are calculated in ATU-R receiver,and sent back to ATU-C according to a defined protocol (see 10.9.14). The pairs of numbers are typically stored, in
ascending order of frequency or tone numbers i, in bit and gain tables for Bitmap-FR and Bitmap-NR.
For Bitmap-FR, the "tone-ordered" encoding shall first assign fRf bits from the rate converter (see Q.4.4.2) to the tones
with the smallest number of bits assigned to them, and the remaining fRi bits to the remaining tones. For Bitmap-NR, it
shall first assign nRf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nRi bits to the remaining tones.
All tones shall be encoded with the number of bits assigned to them; one tone in each bitmap may therefore have a
mixture of bits from the fast and interleaved buffers.
The ordered bit tables b'iF and b'iN shall be based on the original bit tables biF and biN as follows:
For k = 0 to Ndownmax {From the bit table, find the set of all i with the number of bits per tone bi = k
Assign bi to the ordered bit allocation table in ascending order of i}
Two ordered bit tables for Bitmap-FR and Bitmap-NR shall be prepared. A complementary de-ordering procedure
should be performed in ATU-R receiver. It is not necessary, however, to send the results of the ordering process to thereceiver because the bit tables FR and NR were originally generated in ATU-R, and therefore those tables have all theinformation necessary to perform the de-ordering.
Q.4.7
Q.4.7.1

Modulation (pertains to 7.11)
Inverse Synchronization Symbol (replaces 7.11.4)

Except for the pilot tone, Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phasereversal of Synchronization symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
Q.4.7.2

Data subcarriers (modifies 7.11.1.1)

The channel analysis signal defined in 10.6.6 allows for a maximum of NSCds-1 carriers (at frequencies n∆f , n = 1 to
NSCds-1) to be used.
Q.4.7.3

Nyquist frequency (modifies 7.11.1.3)

The carrier at the Nyquist frequency (#NSCds) shall not be used for user data and shall be real valued; other possible
uses are for further study.
Q.4.7.4

Modulation by the inverse discrete Fourier transform (replaces 7.11.2)

The modulating transform defines the relationship between the 2*NSCds real values xn and the Zi:

xn =2* NSCds −1⎛ jπni ⎞∑ exp⎜⎝ NSCds ⎟⎠Zi =0i

for n = 0 to 2 * NSC − 1(7-21)The value of NSCds shall be 1024 for this Annex. However, the highest used subcarrier index shall be limited to 869.
The constellation encoder and gain scaling generate only NSCds-1 complex values of Zi. In order to generate realvalues of xn, the input values (NSCds-1 complex values plus zero at DC and one real value for Nyquist if used) shall beaugmented so that the vector Z has Hermitian symmetry. That is,- 81 -

Zi = conj (Z'2*NSCds-i)
Q.4.7.5

for i = NSCds+1 to 2*NSCds-1(7-22)

Synchronization symbol (modifies 7.11.3)

The synchronization symbol permits recovery of the frame boundary after micro-interruptions that might otherwise
force retraining.
The data symbol rate, fsymb = 4 kHz, the carrier separation, ∆f = 4.3125 kHz, and the IDFT size, N = 2*NSCds, aresuch that a cyclic prefix of 15.625%*NSCds samples could be used. That is, when NSCds = 256, there are 40 samples
in the cyclic prefix.
(512 + 40) × 4.0 = 512 × 4.3125 = 2208

(7-23)

The cyclic prefix shall, however, be shortened to 12.5%*NSCds samples, and a synchronization symbol (with anominal length of NSCds*2.125 samples) is inserted after every 68 data symbols. That is,(2 + 0.125)*NSCds × 69 = (2 + 0.15625)*NSCds × 68(7-24)
The data pattern used in the synchronization symbol shall be the pseudo-random sequence PRD, (dn, for n = 1 to
2*NSCds) defined by:
dn = 1for n = 1 to 9
(7-25)
dn = dn-4 ⊕ dn-9

for n =10 to 2*NSCds(7-26)

The first pair of bits (d1 and d2) shall be used for the DC and Nyquist subcarriers (the power assigned to them is zero,so the bits are effectively ignored); the first and second bits of subsequent pairs are then used to define the Xi and Yi for
i = 1 to NSCds-1 as shown in Table 7-13.
The period of the PRD is only 511 bits, so dn+511 is equal to dn. The d1-d9 shall be re-initialized for eachsynchronization symbol, so each symbol uses the same data.
The two bits that modulate the pilot carrier, shall be overwritten by {0,0}: generating the {+,+} constellation.
The minimum set of subcarriers to be used is the set used for data transmission (i.e. those for which bi > 0); subcarriers

for which bi = 0 may be used at a reduced PSD as defined in transmit PSD paragraphs of Annexes A, B and C. The data
modulated onto each subcarrier shall be as defined above; it shall not depend on which subcarriers are used.
Q.4.7.6

Cyclic prefix (replaces 7.12)

The last 12.5%*NSCds samples of the output of the IDFT (xn for n = 2*NSCds-0.125*NSCds to 2*NSCds-1) shall be
prepended to the block of 2*NSCds samples and read out to the digital-to-analogue converter (DAC) in sequence. For
example, when NSCds=256, the subscripts, n, of the DAC samples in sequence are 480 ... 511, 0 ... 511.
The cyclic prefix shall be used for all symbols beginning with the C-RATES1 segment of the initialization sequence, as
defined in 10.6.2.
Q.4.8

ATU-C Downstream transmit spectral masks (replaces 7.14)

The downstream spectral masks of Annex Q-EU are as specified in this section. When C-MSG1 bit 16 is 0, the PSD
mask as specified in § Q.4.8.1 shall be used. When C-MSG1 bit 16 is 1, the PSD mask as specified in § Q.4.8.2 shall be
used.
Q.4.8.1

Downstream non-overlapped PSD mask definition

The non-overlapped PSD masks are defined with absolute peak values in Figure Q.13. The low frequency stop band isdefined for frequencies below f1 kHz (tone n1); the high frequency stop band is defined at frequencies greater than3750 kHz (tone 869). The in-band region of these PSD masks is the frequency band from f1 kHz to 3750 kHz.

- 82 -

–18 dB/octave

PSD indBm/Hz–2.9 dB/octave–36.5 dBm/Hz peak PSD

36 dB/octave–44.2 dBm/Hz–357 dBm/Hz–100 dBm/Hz peak PSD
in 10 kHz window–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 3925 kHz–50 dBm/Hz–76.5 dBm/Hz–92.5 dBm/Hz–110 dBm/Hz
0

4

f3

f1

1104

3750
3925 4545

1622

Frequency band f (kHz)0<f<4
4 < f < f3
f3 < f < f1
f1 < f < 1104
1104 < f < 1622
1622 < f < 3750

Equation for line (dBm/Hz)
-97.5
-92.5
-92.5 + 36*log2(f/f3)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 2.9*log2(f/1622)

3750 < f < 3925
3925 < f < 12000-76.5 - 357*log2(f/3750)-100

Frequency (kHz)04
4

PSD level (dBm/Hz)
-97.5
-97.5
-92.5

Measurement BW
100 Hz100 Hz100 Hz

f3
f1
f1
1104
1622

-92.5
-44.2
-36.5
-36.5
-46.5

10 kHz
10 kHz
10 kHz
10 kHz
10 kHz3750
3750
3925 – 12000

-50
-76.5
-100

10 kHz
10 kHz
10 kHz- 83 -–112 dBm/Hz

7225

12000

Frequency
in kHzAdditionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
3925
4545
7225
12000

PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

The corner frequencies f1 and f3 depend on the associated upstream PSD mask used, see §Q.5.6) and are defined asfollows:
Mask designator(DS-mm)
DS-32
DS-36
DS-40
DS-44
DS-48
DS-52
DS-56
DS-60
DS-64
NOTE 1 –NOTE 2 –NOTE 3 –NOTE 4 –NOTE 5 –NOTE 6 –Associatedupstream mask
EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

f1 (kHz)f3 (kHz)138
155.25172.5
189.75207
224.25241.5
258.75
276

54.45
61.26
68.06
74.87
81.67
88.48
95.29
102.09108.9

All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint withfrequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued
the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that
this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.
Figure Q.13: Non-overlapped Downstream Channel PSD Masks

Spectral Shaping of the In-Band Region defined in Q.4.8.3 and Transmit Signals with Limited Transmit Power definedin Q.4.8.4 shall be applied.

Q.4.8.2

Downstream Overlapped PSD mask definition

The overlapped PSD mask is defined with absolute peak values in Figure Q.14. The low frequency stop band is definedfor frequencies below 25.875 kHz (tone 6); the high frequency stop band is defined at frequencies greater than3750 kHz (tone 869). The in-band region of this PSD mask is the frequency band from 25.875 kHz to 3750 kHz.

- 84 -

–18 dB/octave

PSD indBm/Hz–36.5 dBm/Hz peak PSD–2.9 dB/octave–50 dBm/Hz

21 dB/octave–357 dBm/octave–100 dBm/Hz peak PSD
in 10 kHz window–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 3925 kHz–76.5 dBm/Hz–92.5 dBm/Hz–110 dBm/Hz
0425.8751104

3750
3925 4545

1622

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < 1104
1104 < f < 1622
1622 < f < 3750

Equation for line (dBm/Hz)-97.5-92.5 + 21*log2(f/4)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 2.9*log2(f/1622)

3750 < f < 3925
3925 < f < 12000-76.5 - 357*log2(f/3750)
-100

7225

Frequency (kHz)04
4
1025.8751104
1622

PSD level (dBm/Hz)
-97.5
-97.5
-92.5
interpolated
-36.5
-36.5
-46.5

Measurement Bandwidth
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz3750
3750
3925 – 12000

-50.0
-76.5
-100

10 kHz
10 kHz
10 kHz

Additionally, the PSD mask shall be satisfying following requirements:
Frequency (kHz)
3925
4545
7225
12000

PSD level (dBm/Hz)
-100
-110
-112
-112

- 85 -–112 dBm/Hz

Measurement Bandwidth
1 MHz
1 MHz
1 MHz
1 MHz

12000

Frequency
in kHzAll PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint withfrequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at themeasurement frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at
frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask
continued the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It wasrecognized that this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.

NOTE 1 –NOTE 2 –NOTE 3 –NOTE 4 –NOTE 5 –NOTE 6 –Figure Q.14: Overlapped Downstream Channel PSD Mask.

Q.4.8.3

Spectral Shaping of the In-Band Region of the PSD Spectrum

In order to shape the ATU-C PSD, frequency dependent gains, called spectral shaping values (ssvi ), shall be applied oneach tone during initialization and showtime. The ssvi values shall be represented with 1 bit before and 10 bits after thedecimal point.
Table Q.2 defines the corner points for the nominal PSD shape of the inband region as gain in dB, i.e log_ssvi. Log_ssvi
on other tones shall be linearly interpolated between corner points on a logarithmic scale for the gain (dB) and a linear
scale for the frequency (Hz). Note that the corner points defined in Table Q.2 are relative values. Table Q.3 defines thesimilar corner points for the overlapped spectrum.
The spectral shaping values shall be converted from logarithmic scale (log_ssvi, dB values) to linear ssvi values
according to:log_ ssvi⎛⎞
Round ⎜⎜1024 × 10 20 ⎟⎟⎝⎠ssvi =
1024

These points are not passed at initialization for the nominal PSD shape but are provided here for reference. However,for additional spectral shaping (see Q.4.8.5), parameters are passed during G.994.1.
The combined accuracy of the process of linear interpolation of the log_ssvi values and the process of conversion tolinear ssvi values shall be strictly less than one half lsb of the 10 bit after the decimal point format of the linear ssvi
values. No error shall be introduced when log_ssvi equals 0dB or is interpolated between log_ssvi values, which equal
0dB.
NOTE 1:NOTE 2:

The above definition ensures that the maximum deviation between ssvi values used by transmitter andreceiver is one lsb.
The above needs an accuracy that is strictly < 1/2 lsb. An accuracy of = 1/2 lsb, will lead to inaccurate
results.

Table Q.2: Corner points for the non-overlapped nominal in-band PSD shape.
Tone Index
n1

Log_ssvi (dB)
0

256
376
869

0
–10
–13.5

Comments
f1 kHz defines the beginning of the inband region. No shaping is applied in the
low stop band.
1104 kHz
1622 kHz ( –10 = –50 – Nominal_PSD_lowband)
3750 kHz ( –13.5 = –53.5 - Nominal_PSD_lowband)- 86 -

Table Q.3: Corner points for the overlapped nominal in-band PSD shape
Tone Index
6

Log_ssvi (dB)
0

256
376
869

0
–10
–13.5

Comments
25.875 kHz defines the beginning of the inband region. No shaping is appliedin the low stop band.
1104 kHz
1622 kHz (–10 = –50 – Nominal_PSD_lowband)
3750 kHz (–13.5 = –53.5 – Nominal_PSD_lowband)

The absolute values of the transmit PSD are obtained by scaling the relative shaping values with a
NOMINAL_PSD_lowband, defined for the lower in-band frequencies. Note that the nominal in-band transmit PSD isfrequency dependent. The NOMINAL_PSD_lowband is –40 dBm/Hz (below 1104 kHz) for both the overlapped andnon-overlapped spectra.
NOTE 3: In-band PSD spectral shaping is applied prior to the IFFT.
NOTE 4: The value of MAXNOMATPds may be limited by regional regulations.
Q.4.8.4

Transmit Signals with Limited Transmit PowerFor cases where the transmit signal must be limited to a maximum aggregate transmit power (e.g. ATPdsmax = +20dBm), thenb)

During initialization the PSD transmit level is specified as an offset from the nominal value, i.e.
(Nominal_PSD_lowband + ssvi – x – power cutback) dB, and all values of gi = 1 for the offset value x and power
cutback. The value of x shall be the greater of 0 dB and (21.1 – ATPdsmax) dB for non-overlapped and (21.5 –ATPdsmax) dB for overlapped. For ATPdsmax = 20 dBm, the corresponding value of x shall be 1.1 dB for nonoverlapped and 1.5 dB for overlapped cases.

b)

If bi>0, then valid range for gi is [-14.5 to +2.5+x] (dB) ;If bi>0, then gi shall be in the [gsync – 2.5 to gsync + 2.5] (dB) range;
If bi=0, then gi shall be equal to 0 (linear) or in the [-14.5 to gsync] (dB) range;
For G.992.1 Annex Q-EU, gsync <= x dB

The gi values shall be constrainted by following relation:
Constraint on gi values

2* NSCds −1∑ ssvi ∗ g i ≤
2

2

i =32

Q.4.8.5

2* NSCds −1

∑ ssv

i =32

2
i

Additional inband spectral shaping

An ATU-R may request additional downstream inband spectral shaping by passing parameters to the ATU-C in a
G.994.1 MP, or MS message. The ATU-C may select additional downstream inband spectral shaping by passing
parameters to the ATU-R in a G.994.1 MS message. Within the framework of G.994.1, the ATU-C has the ability tomake the final decision on the downstream inband PSD shape to be used.
The additional inband spectral shaping parameters are listed in Q.7.2.2 and defined in Q.7.3. If the Additional inband
spectral shaping Spar(2) bit is set to ONE in Table Q.7.2, its associated Npar(3) octets in Tables Q.7.2.1 to Q.7.2.1.5
define the inband spectral shape. If the additional inband spectral shaping Spar(2) bit is set to ZERO, its associatedNpar(3) octets are not transmitted and the nominal inband PSD shape defined in Q.4.8.3 shall be used. These Npar(3)octets define the downstream PSD levels in the low band (between f1 and 1104 kHz), at 1622 kHz and at 3750 kHz.
The PSD levels between 1104 kHz and 1622 kHz, and between 1622 kHz and 3750 kHz are linearly interpolated in log
scale. The defined values are the PSD level in dB below the NOMINAL_PSD_lowband of –40dBm/Hz. For example, if
all three values are set to 20 dB, the result will be a flat PSD of –60dBm/Hz. If the three values are set to 2 dB, 12 dB
and 15.5 dB, the result is the PSD defined in Q.4.8.1 reduced by 2dB. In order not to violate the PSD mask defined in
Q.4.8.1, the second value shall be no less than 10 dB and the third value shall be no less than 13.5 dB.

- 87 -

Q.4.8.6

Egress control

G.992.1 Annex Q-EU equipment shall be able to reduce the PSD below –80 dBm/Hz for the Amateur radio bands
between 1.81 MHz and 2.00 MHz, and between 3.5 MHz and 3.8 MHz. The ATU-C may apply additional spectral
shaping as described in Q.4.8.5 to help achieve this requirement.

Q.4.9

Support of higher downstream bit rates with S = 1/2n (replaces 7.6.4)

With a rate of 4000 data frames per second and a maximum of 255 bytes (maximum RS codeword size) per data frame,
the ADSL downstream line rate is limited to approximately 8 Mbit/s per latency path. The line rate limit can beincreased beyond this for the interleaved path by mapping 2n RS codewords into one FEC data frame (i.e. by using S =1/2n in the interleaved path). S = 1/2n shall be used in the downstream direction only over bearer channel AS0.
For a selected value of n ≥ 1, the KI data bytes per interleaved mux data frame shall be packed into 2n RS codewords,
split into n equal parts, each consisting of 2 consecutive RS codewords. This forces rate adaptation to occur in 32n
kbit/s increments. Each of the n parts of the data frame shall begin with a sync byte and shall obey the rules defined inTable Q.4 for insertion of dummy bytes. The smallest value of n that can support the KI data bytes shall be used.
Support of S = 1/2 (i.e., n=1), S = 1/4 (i.e., n=2), S = 1/6 (i.e., n=3), and S = 1/8 (i.e., n=4), is mandatory.
The resulting data frame structure shall be as shown in Figure Q.15.
N1
Sync
Byte

PayloadN2 = N 1 or N 1-1

R

PayloadR

N2n-1 = N1
Sync
Byte

PayloadN2n = N2

R

PayloadR

NI
Figure Q.15 – Data frame for S = 1/2n mode
When KI is divisible by 2n, the 2n codewords have the same length N2i-1 = N2i = (KI/2n + RI) for i = 1 to n, otherwise
the odd numbered codewords are equal and are one byte longer than the even numbered codewords, i.e. N2i-1 =(KI + n)/2n + RI bytes, and N2i = (KI – n)/2n + RI bytes for i = 1 to n. For the FEC output data frame, NI =

∑ N,
n

i =1

i

with NI < 512n - 1 bytes.
The convolutional interleaver requires all codewords to have the same odd length. To achieve the odd codeword length,
insertion of dummy (not transmitted) bytes may be required. For S = 1/2n, the dummy byte addition to the odd
numbered and/or even numbered codewords at the input of the interleaver shall be as in Table Q.4.

Table Q.4/G.992.1 –Dummy byte insertion at interleaver input for S = 1/2n
N2i-1
Odd
Even
Odd
Even

N2i
Odd
Even
Even
Odd

Dummy Byte Insertion Action
No action
Add one dummy byte at the beginning of all codewords
Add one dummy byte at the beginning of each even numbered codeword
Add one dummy byte at the beginning of each odd numbered codeword and two dummy bytes
at the beginning of each even numbered codeword [the de-interleaver shall insert one dummy
byte into the de-interleaver matrix on the first byte and the (D + 1)th byte of the corresponding
codeword to make the addressing work properly]- 88 -

Q.5

ATU-R Functional Characteristics (pertains to clause 8)

Q.5.1

Framing (pertains to 8.4)

Q.5.1.1

Superframe structure (replaces 8.4.1.1)

The superframe structure of ATU-R transmitter is identical to that of ATU-C transmitter, as specified in Q.4.3.1.
Q.5.1.2

Hyperframe structure (replaces 8.4.1.3)

The hyperframe structure of ATU-R transmitter is functionally similar to that of ATU-C transmitter, except that theinverse synch symbol is used in the 1st superframe (SPF#0) (see Figure Q.16). The hyperframe is composed of 345
DMT symbols, numbered from 0 to 344. Each symbol is under FEXTC or NEXTC duration (see Q.5.3), and thefollowing numerical formula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-R
transmitter (see Figure Q.17).
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbol
then NEXTC symbol

128 DMT symbols are allocated in the FEXTC duration, and 217 DMT symbols are allocated in the NEXTC duration.
The symbols are composed of:
FEXTC symbol:
Number of symbol using Bitmap-FC
Number of synch symbol
Number of inverse synch symbol
NEXTC symbol:
Number of symbol using Bitmap-NC
Number of synch symbol

= 126
=1
=1
= 214
=3

During FEXT Bitmapping mode, the ATU-R shall not transmit any signal.

- 89 -

5 Superframe (= 340 frames)(point B)

1 Superframe = 68 frames (17 ms)

1 frame = 250 µs

Rate-Converter(point U-R, including synch symbol)
TC#6

TTR Clock(TC)#0 = 2.5 ms

TC#33

TTRR
ATU-R
Crosstalk

NEXT

NEXT

FEXT
Hyperframe = 345 symbols (85 ms)

FEXT

ATU-C transmit
DMT symbol N N N N N F F F F N N N

SPF#2

SPF#1

Superframe (SPF#0) = 69 symbols (17 ms)

N F F I F N

S

S

SPF#3

SPF#4
S

S
T1532870-99

Sliding window

FEXTC duration

1 symbol = 246 µs
I

Inverse synch symbol

S

NEXTC Synch symbol

F

Symbol using Bitmap-FC (FEXTC duration bitmap)

N

Symbol using Bitmap-NC (NEXTC duration bitmap)

S

FEXTC Synch symbol

Figure Q.16/G.992.1 – Hyperframe structure for upstream- 90 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

ISS

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

101

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

SS

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

17

173

174

175

176

177

178

179

180

181

172
182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

SS

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

244

245

246

247

248

249

250

251

252

253

24

243

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

SS

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

SS

ISS Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol SS NEXTR synch symbol
NEXTR data symbol

T1535340-00

Figure Q.17/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Upstream

Q.5.1.3

Subframe structure (replaces 8.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table Q.5. The 34 subframes forma hyperframe.

- 91 -

Table Q.5/G.992.1 – Subframe (upstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

Q.5.2

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Inverse Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Synch Symbol#344 is Synch Symbol

Dual Bitmapping and rate conversion (replaces 8.15)

The function of the rate converter (see Q.5.2.2), tone ordering (see Q.5.4), constellation encoding, and gain scaling shalluse one of two bitmaps stored in the ATU. This method is called the dual bitmap.
Q.5.2.1

Dual Bitmap (new)The Dual Bitmap switching shall be the same as for the downstream data, specified in Q.4.4.1. The number of bits andthe relative gains to be used for every tone are calculated in the bit loading algorithm during the initialization sequence,and transmitted in C-B&G.
Q.5.2.2
Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FC, Bitmap-NC and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amounts of fast and interleaved data in Bitmap-FC and Bitmap-NC shall be calculated in thefollowing formulae:
If tCf ≤ nCmax:- 92 -

nCf = tCf
nCi = nC − nCf
f Cf = tCf
f Ci = f C − f Cf
If tCf > nCmax:

nCf = nC max

nCi = 0⎧⎡ tCf × 10 − nCf × 6 ⎤⎪ f Cf 4 = ⎢
⎥
4
⎢
⎪
⎥
f Cf = ⎨⎡ tCf ×10 − nCf × 7 ⎤⎪⎥⎪ f Cf 3 = ⎢3⎢⎥⎩⎧ f Ci 4 = f C − f C 4
f Ci = ⎨⎩ f Ci 3 = f C − f Cf 3
Where:
tCf
tCi
fCf and nCf
fCf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of fast bits in Bitmap-FC if the subframe (see Q.5.1.3) contains 3 Bitmap-FC except
for synch symbols.
fCf4
is the number of fast bits in Bitmap-FC if the subframe contains 4 Bitmap-FC except for synch
symbols.
fCi and nCi
are the numbers of interleaved bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of total bits in Bitmap-NC, which is specified in the B&G tables.
nC
During FEXT Bitmap mode, nCf and nCi are zero.

To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tCf ≤ nCmax:

dummyCf = 0

dummyCi = ( f Ci × 126 + nCi × 214) − tCi × 340
If tCf > nCmax:()
dummyCf 3 = ( f Cf × 3 + nCf × 7 ) − tCf ×10

dummyCf 4 = f Cf × 4 + nCf × 6 − tCf ×10

dummyCi = ( f Ci 4 × 96 + f Ci 3 × 30) − tCi × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FC constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:
dummySCf = fCf3 – fCf4

- 93 -

The receiver shall determine Bitmap-FC and Bitmap-NC so that dummyCi is less than 126, dummyCf4 is less than 4 anddummyCf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.
Q.5.3

FEXT Bitmapping (replaces 8.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (Q.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures Q.10 and Q.16).
Annex Q-EU does not support the FEXT Bitmapping mode.
Q.5.4

Tone Ordering (pertains to 8.7)

The tone ordering algorithm shall be the same as for the downstream data, specified in Q.4.4.
For Bitmap-FC, the "tone-ordered" encoding shall first assign fCf bits from the rate converter (see Q.5.2.2) to the tones
with the smallest number of bits assigned to them, and the remaining fCi bits to the remaining tones. For Bitmap-NC, it
shall first assign nCf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nCi bits to the remaining tones. Two ordered bit tables for Bitmap-FC and Bitmap-NC shall be prepared.
Q.5.5
Q.5.5.1

Modulation (pertains to 8.11)
Inverse synchronization symbol (replaces 8.11.4)

Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phase reversal of Synchronization
symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
Q.5.5.2

Gain scaling in synchronization symbol (new)At initialization time, the sync symbol reference transmit PSD level shall be set at the nominal PSD level+10log(gsync2) dBm/Hz, with gsync2 defined as the average gi2 value over the used (i.e. bi > 0) subcarriers in theNEXT or FEXT bitmap, whichever results in the highest average gain. The sync symbol reference transmit PSD shallnot be updated with used subcarrier gain changes during SHOWTIME.
I.5.5.3

Nyquist frequency (supplements 8.11.1.2)

The upstream Nyquist frequency for Annex Q-EU shall be at subcarrier NSCus (f = 4.3125*NSCus kHz).
I.5.5.4

Modulation by the inverse discrete Fourier transform (supplements 8.11.2)

For Annex Q-EU, see A.2.1.
I.5.5.5

Synchronization symbol (supplements 8.11.3)

For Annex Q-EU, see A.2.2.

Q.5.6

ATU-R Upstream Transmit Spectral Mask (replaces 8.14)

The upstream PSD masks of Annex Q-EU are defined with absolute peak values in Figure Q.18. The low frequency
stop band is defined for frequencies below 25.875 kHz; the high frequency stop band is defined at frequencies greaterthan f1 kHz (tone n1). The in-band region of these PSD masks is the frequency band from 25.875 kHz to f1 kHz.
ATU-x may optionally support upstream masks EU-36 to EU-64 specified in Figure Q.18
NOTE: The value of MAXNOMATPus may be limited by regional regulations.

- 94 -

PSD indBm/HzPEAKPSD(PEAKPSD+92.5)/2.69
dB/octave–72 dB/octave–100 dBm/Hz peak
–15 dB/octave–97.5
15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 1411 kHz–92.5 peak
PSD_int dBm/Hz–110 dBm/Hz–112 dBm/Hz

0425.875

f1

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < f1
f1< f < f_int
f_int < f < 686
f > 686
Frequency (kHz)04
425.875f1
f_int
686 – 12000

f_int

686

1411
1630 5275

Equation for line (dBm/Hz)-97.5-92.5+(PEAKPSD+92.5)* log2(f/4)/log2(25.875/4)
PEAKPSDPEAKPSD-72*log2(f/f1)
PSD_int-15*log2(f/f_int)-100
PSD level (dBm/Hz)
-97.5
-97.5
-92.5
PEAKPSDPEAKPSD
PSD_int-100

Measurement BW
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz

Additionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
1411
1630
5275
12000

Frequency
12000 in kHz

PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

NSCus is a function of the upstream mask parameters, which are defined as follows:- 95 -

Parameters in FEXT bitmap for mode 1, both bitmaps for mode 2 (see §Q.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

32
64
64
64
64
64
64
64
64

Template
Nominal PSD
P0 (dBm/Hz)

-38.0
-38.5
-39.0
-39.4
-39.8
-40.1
-40.4
-40.7
-41.0

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.0
-35.5
-35.9
-36.3
-36.6
-36.9
-37.2
-37.5

138.00155.25172.50189.75207.00224.25241.50258.75276.00242.92274.03305.06336.33367.54399.07430.58462.04493.45

-93.2
-94.0
-94.7
-95.4
-95.9
-96.5
-97.0
-97.4
-97.9

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.2
-36.4
-37.2
-37.9
-38.3
-38.6
-38.8
-38.8

138.00155.25172.50189.75207.00224.25241.50258.75276.00242.92273.47302.26331.87361.55392.16423.12454.51486.91

-93.2
-94.0
-94.7
-95.3
-95.8
-96.4
-96.9
-97.3
-97.8

Parameters in NEXT bitmap for mode 1 (see §Q.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

Template
NominalPSD P0(dBm/Hz)

32
64
64
64
64
64
64
64
64

-38.0
-38.7
-39.9
-40.7
-41.4
-41.8
-42.1
-42.3
-42.3

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

NOTE 1 – All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
NOTE 2 – The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The breakpoints
in the tables shall be connected by linear straight lines on a dB/log(f) plot.
NOTE 3 – MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint with frequency fi
is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next specified breakpoint.
NOTE 4 – The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
NOTE 5 – The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued the21.5 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that this might impact
V.90 performance, and so the floor was extended to 4 kHz.
NOTE 6 – All PSD and power measurements shall be made at the U-R interface (see Figures Q.3 & Q.4).
Figure Q.18: Upstream Channel PSD Masks

Q.5.7

Forward error correction (supplements 8.6)

The minimum FEC coding capabilities (Table 8-3) for an ATU-R shall include the following interleave depths for theinterleaved buffer:
D = 1, 2, 4, 8, and 16- 96 -

Q.5.8Cyclic prefix (supplements 8.12)

For Annex Q-EU, see A.2.3.

Q.6

EOC Operation and Maintenance (pertains to clause 9)

Q.6.1

ADSL line related primitives (supplements 9.3.1)

Q.6.1.1

ADSL line related near-end defects (supplements 9.3.1.3)

Two near-end defects are further defined:••

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.
Severely errored frame (SEF): A SEF defect occurs when the content of two consecutively received ADSL
synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R, does notcorrelate with the expected content over a subset of the tones. An SEF defect terminates when the content of twoconsecutively received ADSL synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR
duration at ATU-R, correlate with the expected contents over the same subset. The correlation method, theselected subset of tones, and the threshold for declaring these defect conditions are implementation discretionary.

Q.6.1.2

ADSL line related far-end defects (supplements 9.3.1.4)

Loss-of-signal is further defined:•

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.

Q.6.2

Test Parameters (supplements 9.5)

Q.6.2.1

Near-end test parameters (supplements 9.5.1)

The near-end primitives are further defined:••

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio (SNR) margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.

Q.6.2.2

Far-end test parameters (supplements 9.5.2)

The far-end primitives are further defined:
•
•

Q.6.3

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio SNR margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.
Data registers in the ATU-R (supplements 9.2.4)

For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7

Initialization (pertains to clause 10)- 97 -

Q.7.1

Initialization with Hyperframe (replaces 10.1.5)

The exchange of messages between ATU-C and ATU-R should be performed in FEXTC and FEXTR. The DMT
symbol has two symbol rates: one is 4.3125 kbaud for the symbol without a cyclic prefix, and the other is 4 x 69/68
kbaud for the symbol with a cyclic prefix. 32 times of the TTR has the same period as 345 times of the 4.3125 kbaud,
and 34 times of the TTR is the same as 345 times of 4 x 69/68 kHz.
During FEXT Bitmap mode, the ATU-R shall not transmit any signal during the NEXTC symbols duration and the
ATU-C shall transmit only the pilot tone as the NEXTR signal except:• C-PILOT1 (C-PILOT1A) which is accompanied by a signal to allow the ATU-C to indicate the phase of TTRC
to the ATU-R (see Q.7.4.1);• C-QUIETn where no signal is transmitted.
The ATU-C begins transmitting C-PILOT1 at the beginning of the hyperframe without cyclic prefix. The ATU-C
informs the phase of the TTRC to ATU-R during C-PILOT1. The ATU-R begins transmitting R-REVERB1 at the
beginning of the hyperframe without cyclic prefix. The ATU-R performs the training of any receiver equalizer using
this phase information of the TTRR generated from received TTRC.
From C-PILOT1 to C-SEGUE1, the following numerical formula gives the information which duration Ndmt-th DMT
symbol belongs to at ATU-R (see Figure Q.19).
For Ndmt = 0, 1, …344
S = 256 x Ndmt mod 2760
if { (S + 255 < a) or (S > a + b) }else
where a = 1243, b = 1461

then FEXTR symbols
then NEXTR symbols

In order to enter C-RATES1 at the beginning of the hyperframe with cyclic prefix, the number of symbols from
C-PILOT1 to C-SEGUE1 shall be a multiple of 345 DMT symbols.
From R-REVERB1 to R-SEGUE1, the following numerical formula gives the information which duration Ndmt-th
symbol belongs to at ATU-C (see Figure Q.20).
For Ndmt = 0, 1, …, 344,
S = 256 x Ndmt mod 2760
if { (S > a) and (S + 255 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols

From C-RATES1 to C-SEGUE3, the number of symbols is a multiple of 345 DMT symbols. The following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-C transmits the message data in
FEXTR symbols (see Figure Q.11).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760

if { (S + 271 ≥ a) and (S ≤ a + b) }else
where a = 1243, b = 1461

then NEXTR symbols
then FEXTR symbols

The ATU-R enters R-REVERB3 at the beginning of the hyperframe with cyclic prefix, which is extracted fromreceived signal. From R-REVERB3 to R-SEGUE5, the number of symbols is a multiple of 345 DMT symbols. The
following numerical formula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-R transmits
the message data in FEXTC symbols (see Figure Q.17).

- 98 -

For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14

0

1

2

3

4

5

6

7

8

9

10

11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
107
97
98
99
100
101
102
103
104
105
106
108
109
110
111
112
113
114
115
116
117 118
119
120
121
122
123
124
125
126
127
128
129 130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
161
151
152
153
154
155
156
157
158
159
160

162
163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181
182
184
185
186
187
188
189
190
191
192
193
17 183
204
195
196
197
198
199
200
201
202
203
18 194
205
206
207
208
209
210
211
212
213
214 215
19
20
216
217
218
219
220
221
222
223
224
225
228
229
230
231
232
233
234
235
236
21 226 227
238
239
240
241
242
243
244
245
246
247
22 237
258
248
249
250
251
252
253
254
255
256
257
23
24
259
260
261
262
263
264
265
266
267
268 269
15
16

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311 312
313
314
315
316
317
318
319
320
321
322
29
325
326
327
328
329
330
331
332
333
30 323 324
335
336
337
338
339
340
341
342
343
344
31 334
25
26
27
28

280

FEXTR symbol

T1535350-00

NEXTR symbol

Figure Q.19/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Downstream- 99 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

10

1

11

12

13

14

15

16

17

18

19

20

2

22

23

24

25

26

27

28

29

30

31

3 32
4 43
5

33

34

44

54

35

45

55

6

65

7 75
8 86

76

56

66

57

77
98

99

108

109

110

23
24

82

92

102

112

62

72

63

73

83

93

103

113

64

74

84

94

104

114

53

85

95

105

115

96
107

106

116

117

118

121

122

123

124

125

126

127

128

132

133

134

135

136

137

138

139

142

143

153

163

144

154

164

145

155

165

146

156

166

147

157

167

148

158

168

149

159

169

150
161

160

170

171

172

174

175

176

177

178

179

180

181

182

184

185

186

187

188

189

190

191

192

193
204

195

205

196

206

216

21 22622 239

81

91

101

111

61

71

42

52

173

17 18318 194
19
20

80

41

51

131
152

162

15
16

60

70

90

40

50

120

141

140
151

59

79
100

39

49

69

89

97

14

58

78

9

38

48

68

88

10

13

37

47

67

87

119
11
12 129 130

36

46

21

197

207

217

198

208

218

199

209

219

200

210

220

201

211

221

202

212

222

203

213

223

215

214

224

225

227

228

229

230

231

232

233

234

235

236

238

239

240

241

242

243

244

245

246

247
258

248

249

259

250

260

251

261

252

262

253

263

254

264

255

265

256

266

257

267

268

269

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
26 280
292
293
294
295
296
297
298
299
300
301
27 291
28
302
303
304
305
306
307
308
309
310
311
312
25

29
30 32331 334

313

314

324
335

315

325
336

316

326
337

317

327

318

328

338

339

319

329
340

320

330
341

321

331
342

322

332
343

333
344
T1535360-00

FEXTC symbol
NEXTC symbol

Figure Q.20/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Upstream

Q.7.2

Handshake – Non-standard information block (new)This section defines the format of the G.994.1 non-standard information block to support Annex Q-EU, and tabulates
the parameters used by Annex Q-EU. The use of these parameters is described in §Q.7.3 and §Q.7.4.

Q.7.2.1 Non-standard information block format (new)Figure Q.21 defines the format of the non-standard information block.

- 100 -

8

7

6

5

4

3

2

1

Non-standard information length = M + 6(1 octet)
T.35 country code
(2 octets – see Note 1)
Provider code (vendor identification)(4 octets – see Note 2)
Vendor-specific information(M octets – Note 3)
NOTE 1 – The value of this field shall be B5 00, the country code for USA
NOTE 2 – The value of this field shall be 43 45 4E 54, ASCII “CENT” for Centillium
Communications
NOTE 3 – These octets are defined in §Q.7.2.2. Formatting of these octets shall comply with theparsing rules defined in G.994.1 §9.2.1 to §9.2.3

Figure Q.21 – Non-standard information block format

Q.7.2.2 Non-standard information block parameters (new)The G.994.1 non-standard parameters for Annex Q-EU are listed in Tables Q.6 to Q.7.2.1.2.5 below.
In order to minimize message length, the parameters for additional inband spectral shaping (Spar(2) octet and its related
Npar(3) octets) shall only be included in MP or MS messages, and shall not be included in CLR or CL messages. All
Annex Q-EU modems shall support additional inband spectral shaping.
Note - This deviates from the rules specified in G.994.1 for standard information fields, where it isstated in §9.6:“Once a Transaction C (see 10.1) has been completed, any subsequent MS message
within the same G.994.1 session shall only contain those octets of the identification (I)and standard information (S) fields, and those blocks of non-standard information (NS)that were contained in both the CLR and CL messages of the previous Transaction C”.

Table Q.6 – Non-standard information field – NPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Reserved for future use

x

x

x

x

x

x

1

x

Reserved for future use

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet- 101 -

NPar(1)sTable Q.7 – Non-standard information field – SPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

G.992.1 Annex Q (and Annex Q-EU)

x

x

x

x

x

x

1

x

G.992.1 Annex I-EU

x

x

x

x

x

1

x

x

G.992.1 Annex C-EU

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet

SPar(1)sTable Q.7.1 – Non-standard information field – G.992.1 Annex Q NPar(2) coding – Octet 1
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

nC-PILOT1 = 64

x

x

x

x

x

x

1

x

nC-PILOT1 = 128

x

x

x

x

x

1

x

x

nC-PILOT1 = 256

x

x

x

x

1

x

x

x

Amateur radio notch – 1.8 MHz band

x

x

x

1

x

x

x

x

Amateur radio notch – 3.5 MHz band

G.992.1 Annex Q NPar(2)s – Octet 1

x

x

1

x

x

x

x

x

nC-PILOT1 = 96

x

x

0

0

0

0

0

0

No parameters in this octet

Since A48 is the only TTR indication signal specified for Annex Q-EU, there is no need to include it in G.994.1.

Table Q.7.1.1 – Non-standard information field – G.992.1 Annex Q NPar(2) coding – Octet 2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

R-ACK1

x

x

x

x

x

x

1

x

R-ACK2

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

G.997.1 – Clear EOC OAM

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex Q NPar(2)s – Octet 2

Since Annex Q-EU only supports ATM transport, STM and ATM parameters are not specified. Since FBM mode is
not supported, the DBM bit is also not specified.

- 102 -

Table Q.7.2 – Non-standard information field – G.992.1 Annex Q SPar(2) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Additional inband spectral shaping

x

x

x

x

x

x

1

x

Extended upstream

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex Q SPar(2)s

Table Q.7.2.1 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 1
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 1x

x

NOMINAL_PSD_lowband (bits 8 & 7)x

Reserved for future use

Table Q.7.2.1.1 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 2
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 2

x

x

x

x

x

x

x

x

NOMINAL_PSD_lowband (bits 6 to 1)

Table Q.7.2.1.2 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 3
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 3x

x

PSD level at 1622 kHz (bits 8 & 7)x

Reserved for future use- 103 -

Table Q.7.2.1.3 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 4
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 4

x

x

x

x

x

x

x

x

PSD level at 1622 kHz (bits 6 to 1)

Table Q.7.2.1.4 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 5
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 5x

x

PSD level at 3750 kHz (bits 8 & 7)x

Reserved for future use

Table Q.7.2.1.5 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 6
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 6

x

x

x

x

x

x

x

x

PSD level at 3750 kHz (bits 6 to 1)

Table Q.7.2.2 – Non-standard information field – G.992.1 Annex Q Extended upstream
NPar(3) coding Octet 1
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Extended upstream NPar(3)s Octet
1

x

x

x

x

x

x

x

1

Mode 1 upstream mask

x

x

x

x

x

x

1

x

Mode 2 upstream mask

x

x

x

x

x

1

x

x

Optional upstream masks for non-overlapped spectrum

x

x

x

x

1

x

x

x

EU-64

x

x

x

1

x

x

x

x

EU-32

x

x

1

x

x

x

x

x

EU-36

x

x

0

0

0

0

0

0

No parameters in this octet- 104 -

Table Q.7.2.2.1 – Non-standard information field – G.992.1 Annex Q Extended upstream
NPar(3) coding Octet 2
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Extended upstream NPar(3)s Octet
2

x

x

x

x

x

x

x

1

EU-40

x

x

x

x

x

x

1

x

EU-44

x

x

x

x

x

1

x

x

EU-48

x

x

x

x

1

x

x

x

EU-52

x

x

x

1

x

x

x

x

EU-56

x

x

1

x

x

x

x

x

EU-60

x

x

0

0

0

0

0

0

No parameters in this octet

Q.7.3

Handshake – Parameter definitions (supplements 10.2)

Q.7.3.1 Handshake – ATU-C (supplements 10.2)
Q.7.3.1.1

CL messages (supplements 10.2.1)

See Table Q.8.

Table Q.8/G.992.1 – ATU-C CL message NPar(2) bit definitions for Annex Q
NSF parameter

Definition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-C is configured to support G.992.1
Annex Q, and possibly Annex Q-EU.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 96.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 256.
If set to ONE, this Npar(2) bit indicates that the ATU-C is configured to reduce its transmit
power between 1.81 and 2.0 MHz to ≤ –80 dBm.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band

Extended upstream

If set to ONE, this Npar(2) bit indicates that the ATU-C is configured to reduce its transmit
power between 3.5 and 3.8 MHz to ≤ –80 dBm.

If set to ONE, this Spar(2) bit indicates that the ATU-C is configured to support extended
upstream.

- 105 -

EU-xxMode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped
spectrumQ.7.3.1.2

If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-C supports. For non-overlapped spectrum, extended upstream
masks are associated with downstream masks according to Figure Q.13. For overlapped
spectrum, any EU-xx may be used with the overlapped downstream spectrum specified in§Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support the optional
upstream masks when using non-overlapped spectrum downstream.

MS messages (supplements 10.2.2)

See Table Q.9.

Table Q.9/G.992.1 – ATU-C MS message NPar(2) bit definitions for Annex Q
NSF bitG.992.1 Annex Q
nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_
lowband
PSD level at 1622
kHz

PSD level at 3750
kHz

Definition

If set to ONE, this Spar(1) bit indicates that the ATU-C is selecting G.992.1 Annex Q, andpossibly Annex Q-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 256 (Note 1).
If set to ONE, this Npar(2) bit indicates that the ATU-C shall reduce its transmit power
between 1.81 and 2.0 MHz to ≤ –80 dBm.
If set to ONE, this Npar(2) bit indicates that the ATU-C shall reduce its transmit power
between 3.5 and 3.8 MHz to ≤ –80 dBm.
If set to ONE, this Spar(2) bit indicates that the ATU-C shall apply additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply in the passband below 1104 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply at 1622 kHz. It is coded in steps of 0.125dB relative to NOMINAL_PSD_lowband(–40dBm/Hz). For example, 00000000 means –40 dBm/Hz; 00001101 means -41.625
dBm/Hz. The PSD level shall be linearly interpolated in dBs between the
REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply at 3750 kHz. It is coded in steps of 0.125dB relative to NOMINAL_PSD_lowband(–40dBm/Hz). For example, 00000000 means –40 dBm/Hz; 00001101 means -41.625
dBm/Hz. The PSD level shall be linearly interpolated in dBs between the PSD level at 1622
kHz and the PSD level at 3750 kHz.

- 106 -

Extended upstream
EU-xx

If set to ONE, this Spar(2) bit indicates that the ATU-C is selecting extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-C is selecting upstream PSD mask USxx. For non-overlapped spectrum, extended upstream masks are associated with downstream
masks according to Figure Q.13. For overlapped spectrum, any EU-xx may be used with theoverlapped downstream spectrum specified in §Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 1(different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 2(same mask during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped
spectrum
Note 1: One and only one pilot tone bit shall be set in an MS message.
Note 2: One and only one upstream mask mode bit shall be set in an MS message.

Q.7.3.2 Handshake – ATU-R (supplements 10.3)
Q.7.3.2.1

CLR messages (supplements 10.3.1)

See Table Q.10.

Table Q.10/G.992.1 – ATU-R CLR message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-R is configured to support G.992.1
Annex Q, and possibly Annex Q-EU.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 96.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 256.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports the 1.8 MHz
Amateur radio band notch.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports the 3.5 MHz
Amateur radio band notch.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Amateur radio notch– 3.5 MHz band

Extended upstream
EU-xx

Mode 1 upstreammask

If set to ONE, this Spar(2) bit indicates that the ATU-R is configured to support extended
upstream.
If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-R supports. For non-overlapped spectrum, extended upstream
masks are associated with downstream masks according to Figure Q.13. For overlapped
spectrum, any EU-xx may be used with the overlapped downstream spectrum specified in§Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).

- 107 -

Mode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum

Q.7.3.2.2

If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support the optional
upstream masks when using non-overlapped spectrum downstream.

MS messages (supplements 10.3.2)

Table Q.11.

Table Q.11/G.992.1 – ATU-R MS message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-R is selecting G.992.1 Annex Q, andpossibly Annex Q-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_
lowband
PSD level at 1622
kHz

PSD level at 3750
kHz

Extended
upstream
EU-xx

Mode 1 upstream
maskThis selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 3750 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 3750 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-R is selecting upstream PSD mask USxx. For non-overlapped spectrum, extended upstream masks are associated with downstream
masks according to Figure Q.13. For overlapped spectrum, any EU-xx may be used with theoverlapped downstream spectrum specified in §Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode 1(different masks during FEXT and NEXT periods). (Note 2)- 108 -

Mode 2 upstream
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode 2
mask(same mask during FEXT and NEXT periods). (Note 2)
Optional upstream If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting one of the optionalmasks for nonupstream masks when using non-overlapped spectrum downstream.
overlapped
spectrum
Note 1: One and only one pilot tone bit shall be set in an MS message.
Note 2: One and only one upstream mask mode bit shall be set in an MS message.

Q.7.3.2.3

MP messages (new)Table Q.12.
Table Q.12/G.992.1 – ATU-R MP message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-R is proposing G.992.1 Annex Q, andpossibly Annex Q-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is proposing the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_lowbandPSD level at 1622
kHz

PSD level at 3750
kHz

Extended upstream
EU-xx

Mode 1 upstream
maskThis selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs between
the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 3750 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs between
the PSD level at 1622 kHz and the PSD level at 3750 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-R is proposing upstream PSD mask USxx. For non-overlapped spectrum, extended upstream masks are associated with downstream
masks according to Figure Q.13. For overlapped spectrum, any EU-xx may be used with theoverlapped downstream spectrum specified in §Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode 1(different masks during FEXT and NEXT periods).

- 109 -

Mode 2 upstream
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode 2
mask(same mask during FEXT and NEXT periods).
Optional upstream
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing one of the optionalmasks for nonupstream masks when using non-overlapped spectrum downstream.
overlapped
spectrum
Note 1: More than one pilot tone bit may be set in an MP message.

Q.7.4

Transceiver Training – ATU-C (supplements 10.4)

During transceiver training from C-REVERB1 to C-SEGUE1 except C-PILOTn and C-QUIETn, the ATU-C shalltransmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), and shall not transmit
the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state isdefined as Figure Q.26.
Q.7.4.1

C-PILOT1 (supplements 10.4.2)

The ATU-C shall start the NSWF (sliding window frame) counter from 0 immediately after entering C-PILOT1, andincrement the NSWF counter modulo 345 after transmission of each DMT symbol. According to the sliding windowfunction and this counter, the ATU-C decides to transmit all of the subsequent symbols in either FEXTR or NEXTR
symbols (for example, see Figures Q.11, Q.19 and Q.24).
C-PILOT1 has two signals.
The first signal is the pilot tone, a single frequency sinusoid at fC-PILOT1 defined as:⎧ 0, k ≠ nC − PILOT 1 , 0 ≤ k ≤ NSCds
Xk = ⎨
AC − PILOT 1 , k = nC − PILOT 1⎩
The frequency of the pilot tone shall be selected from one of the following choices during G.994.1 as:
4. fC-PILOT1 = 276 kHz (nC-PILOT1 = 64).
5. fC-PILOT1 = 414 kHz (nC-PILOT1 = 96).
6. fC-PILOT1 = 552 kHz (nC-PILOT1 = 128).
7. fC-PILOT1 = 1104 kHz (nC-PILOT1 = 256).
Transmitters that support Annex Q-EU shall support all of these pilot tones.
The second signal is the TTR indication signal used to transmit NEXTR/FEXTR information. The ATU-R can detect
the phase information of the TTRC from this signal. The TTR indication signal shall be selected during G.994.1 as:
A48 signal –the constellation encoding of the 48th carrier with 2-bit constellation as follows:(+ , +) to indicate a FEXTR symbol;(+ , –) to indicate a NEXTR symbol.
Q.7.4.2

C-PILOT1A (supplements 10.4.3)

C-PILOT1A has two signals and it is the same transmitted signal as C-PILOT1 (C.7.4.1).
Q.7.4.3

C-REVERB3 (supplements 10.4.11)

In order to synchronize the first symbol of C-RATES1 with the beginning of the hyperframe and to inform the enteringtiming of C-RATES1 to the ATU-R, the first symbol of C-SEGUE1 shall be transmitted inside of the FEXTR duration
as shown in Figure Q.22. Therefore, the duration of C-REVERB3 is 3628 DMT symbols.

- 110 -

TTRC
20 symbols
C-SEGUE1

C-REVERB3

C-RATES1

the time of the detection
C-SEGUE1

R-REVERB3
T1532880-99

Figure Q.22/G.992.1 – Timing diagram from C-SEGUE1 to C-RATES1

Q.7.4.4 C-REVERB1 (replaces 10.4.5)
C-REVERB1 is a signal that allows the ATU-C and ATU-R receiver to adjust its automatic gain control (AGC) to an
appropriate level. The data pattern used in C-REVERB1 shall be the pseudo-random downstream sequence (PRD), dn
for n = 1 to 2*NSCds, defined in Q.4.7.5 and repeated here for convenience:dn = 1dn = dn-4 ⊕ dn-9

for n = 1 to 9
for n = 10 to 2*NSCds(10-1)The bits shall be used as follows: the first pair of bits (d1 and d2) is used for the DC and Nyquist subcarriers (the powerassigned to them is, of course, zero, so the bits are effectively ignored); then the first and second bits of subsequentpairs are used to define the Xi and Yi for i = 1 to NSCds-1 as defined in Table 7-13.
The period of PRD is only 511 bits, so dn+511 is equal to dn. The bits d1 to d9 shall be re-initialized for each symbol,
so each symbol of C-REVERB1 is identical.
The two bits that modulate the pilot carrier shall be overwritten by {0,0}: generating the {+,+} constellation.
The duration of C-REVERB1 is 512 (repeating) symbols without cyclic prefix.
Q.7.4.4.1

Power Cut-back (supplements 10.4.5.1)

For Annex Q-EU, see A.3.1.

Q.7.5

Transceiver Training – ATU-R (supplements 10.5)

During transceiver training from R-REVERB1 to R-SEGUE1 except R-QUIETn, the ATU-R shall transmit both
FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC
symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is defined as Figure Q.26.
Q.7.5.1

R-QUIET2 (supplements 10.5.1)

The ATU-R enters R-REVERB1 after it completes timing recovery and Hyperframe synchronization from
C-PILOT1/C-PILOT1A.
Q.7.5.2

R-REVERB1 (supplements 10.5.2)- 111 -

The data pattern used in R-REVERB1 is the pseudo-random upstream sequence PRU defined in 8.11.3, repeated asnecessary for the the selected NSCus:⎧d n = 1⎨⎩d n = d n − 5

for n = 1 to 6
⊕ d n −6 for n = 7 to 2 * NSCus(C.10-1)

The period of PRU is only 63 bits, so dn+63 is equal to dn.
The ATU-R shall start its NSWF counter immediately after entering R-REVERB1, and then increment the NSWF
counter with modulo 345 from 0 when it transmits each DMT symbol. The ATU-C and ATU-R shall have the samevalue since hyperframe alignment between the ATU-C and ATU-R shall be maintained. According to the sliding
window and this counter, the ATU-R decides to transmit all of the subsequent symbols in either the FEXTC or the
NEXTC symbol.
Q.7.5.3

R-QUIET3 (replaces 10.5.3)

The final symbol of R-QUIET3 accommodates the frame alignment of the transmitter to that of the receiver. It may be
shortened by any number of samples. The maximum duration of R-QUIET3 is 6145 DMT symbols.
Q.7.5.4

R-REVERB2 (supplements 10.5.5)

After ATU-R detects C-SEGUE1, the ATU-R enters R-SEGUE1. The maximum duration of R-REVERB2 is 3643
DMT symbols.
Q.7.6

Channel analysis (ATU-C) (supplements 10.6)

ATU-C shall transmit only FEXTR symbols, and shall not transmit the NEXTR symbols except the pilot tone from
C-RATES1 to C-CRC2. During C-MEDLEY, the ATU-C shall transmit both FEXTR and NEXTR symbols when
Bitmap-NR is enabled (Dual Bitmap mode). The ATU-C shall not transmit NEXTR symbols except the pilot tone,
when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state is defined in Figure Q.26.
Q.7.6.1

C-SEGUE1 (supplements 10.6.1)

The duration of C-SEGUE1 is 20 symbols in order that the first symbol of C-SEGUE1 shall be inside of the FEXTR
duration.
Q.7.6.2

C-MEDLEY (replaces 10.6.6)

C-MEDLEY is a wideband pseudo-random signal used for estimation at the ATU-R of the downstream SNR. The data
to be transmitted are derived from the pseudo-random sequence, PRDm defined as:
d n = 1 for n = 1 to 14 and d n = d n-5 ⊕ d n-11 ⊕ d n-12 ⊕ d n-14 for n> 14,
and modulated as defined in 10.4.5. In contrast to C-REVERB1, the cyclic prefix is used and the data sequence
continues from one symbol to the next (i.e. d1 to d14 are not re-initialized for each symbol). Because the sequence is oflength 214-1, and far fewer bits are used for each symbol, the subcarrier vector for C-MEDLEY changes from one
symbol period to the next. For non-overlapped spectrum, 2*(869-mm+1) bits are used each symbol, where mm is theminimum subcarrier specified for PSD mask DS-mm in Table Q.13. For overlapped spectrum, 2*864 bits are used eachsymbol. The pilot subcarrier is overwritten by the (+,+) signal constellation. The duration of C-MEDLEY is as shown in
Figure Q.26. Following C-MEDLEY the ATU-C shall enter the state C-REVERB4.
With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure Q.23. The ATU-C
transmits the signal in both of NEXTR and FEXTR symbols, and the ATU-R estimates two SNRs from the received
NEXTR and FEXTR symbols, respectively, as defined in Figure Q.24.

- 112 -

The following formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > d) }if { (S > b) and (S + 271 < c) }where a = 1243, b = 1403, c = 2613, d = 2704

then symbol for estimation of FEXTR SNR
then symbol for estimation of NEXTR SNR

When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbol. The
number of bits of NEXTR shall be no more than the number of bits of FEXTR.
At the transmitter, the PRDm sequence generator shall continue to be updated during NEXTR symbols when BitmapNR is disabled (FEXT Bitmap mode).

TTR
TCM-ISDN crosstalkat ATU-R receiver

TCM-ISDN crosstalkat ATU-C receiver

NEXT

NEXT

FEXT

FEXT

FEXT

NEXT

NEXT

NEXT

FEXT

FEXT
Estimation of
Signal-to-Noise ratio

C/R-MEDLEY (49152 symbols)

Bitmap for Downstream

Bitmap-NR

Bitmap-FR

Bitmap-FR

Bitmap-NR

Bitmap for Upstream

Bitmap-FC

Bitmap-NC

Bitmap-NC

Bitmap-FC
T1532890-99

Figure Q.23/G.992.1 – Estimation of periodic Signal-to-Noise Ratio- 113 -

TTRC
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

4
5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

101

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

137

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

17
18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

206

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

243

24

244

245

246

247

248

249

250

251

252

253

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

275

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

315

316

317

318

319

320

321

322

323

324

31

314

32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

Symbol for estimation of FEXTR S/N
Symbol for estimation of NEXTR S/N

Symbol not used for S/N estimation
T1535370-00

Figure Q.24/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Downstream

Q.7.6.3

C-RATES1 (supplements 10.6.2)

In order to support data rates greater than 32 Mbit/s, the BI field has 11 bits. The RRSI fields shall use the same
extended syntax as defined in Q.7.9.4 for C-RATES-RA.

- 114 -

For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7.6.4

C-MSG1 (supplements 10.6.4)

Table Q.13/G.992.1 – Assignment of 48 bits of C-MSG1
Suffix(ces) of mi (Note 1)
Parameter (Note 3)
47-44
Minimum required downstream SNR margin at initialization (Note 2)
43-18
Reserved for future use
17
Trellis coding option
16
Overlapped spectrum option (Note 4)
15
Unused (shall be set to "1")
14-12
Reserved for future use
11
NTR
10-9
Framing mode
8-6
Transmit PSD during initialization
5
Reserved
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – A positive number of dB; binary coded 0-15 dB.
NOTE 3 – All reserved bits shall be set to "0".
NOTE 4 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
Q.7.6.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.6.4.8)

The Ndownmax (transmit) capability shall be binary encoded onto {m4, ..., m0} (e.g. 100012 = 17). The maximum
number of bits for the upstream data, Nupmax, that the ATU-C receiver can support need not be signalled to the ATU-R;
it will be implicit in the bits and gains message, C-B&G, which is transmitted after channel analysis.
Q.7.7

Channel analysis (ATU-R) (supplements 10.7)

From R-RATES1 to R-CRC2, the ATU-R shall transmit only the FEXTC symbols and shall not transmit the NEXTC
symbols. In R-SEGUE2 and R-MEDLEY, the ATU-R shall transmit both FEXTC and NEXTC symbols when
Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC symbols when Bitmap-NC is disabled(FEXT Bitmap mode). The duration of each state is defined in Figure Q.26.
Q.7.8

R-SEGUE1 (supplements 10.7.1)

The maximum duration of R-SEGUE1 is 14 symbols (see Figure Q.22).
Q.7.8.1

R-REVERB3 (supplements 10.7.2)

The ATU-R shall start R-REVERB3 aligned with the beginning of a Hyperframe.
Q.7.8.2

R-SEGUE2 (supplements 10.7.3)

The duration of R-SEGUE2 is 13 symbols.
Q.7.8.3

R-MEDLEY (replaces 10.7.8)

R-MEDLEY is a wideband pseudo-random signal used for estimation of the upstream SNR at the ATU-C. The data to
be transmitted are derived from the pseudo-random sequence PRUm defined as:
d n = 1 for n = 1 to 23 and d n = d n-18 ⊕ d n-23 for n> 23.
In contrast to R-REVERB1, the cyclic prefix is used and the data sequence continues from one symbol to the next (i.e.

- 115 -

d1 to d23 are not re-initialized for each symbol). Because the sequence is of length 223-1, and 2*(nn-5) bits are used foreach symbol (where nn is the maximum subcarrier specified for PSD mask EU-nn in Table Q.18), the subcarrier vector
for R-MEDLEY changes from one symbol period to the next. Following R-MEDLEY the ATU-R enters signalling state
R-REVERB4. The duration of R-MEDLEY is as shown in Figure Q.26.
With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure Q.23. ATU-R shalltransmit the signal in both of NEXTC and FEXTC symbols, and ATU-C shall estimate two SNRs from the received
NEXTC and FEXTC symbols, respectively, as defined in Figure Q.25.
The following numerical formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > b) and (S + 271 < c) }if { (S + 271 < a) }where a = 1148, b = 1315, c = 2608

then symbol for estimation of FEXTC SNR
then symbol for estimation of NEXTC SNRWhen Bitmap-NC is disabled (FEXT Bitmap mode), the ATU-R shall not transmit NEXTC symbol. The number of bitsof NEXTC shall be no more than the number of bits of FEXTC.
At the transmitter, the PRUm sequence generator shall continue to be updated during NEXTC symbols when BitmapNC is disabled (FEXT Bitmap mode).

- 116 -

TTR R
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

101

10

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

11
12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

137

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

172

17

173

174

175

176

177

178

179

180

181

182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

206

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

243

24

244

245

246

247

248

249

250

251

252

253

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

275

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

T1535290-00

Symbol for estimation of FEXT C S/N

Symbol not used for S/N estimation

Symbol for estimation of NEXT C S/N

Figure Q.25/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Upstream- 117 -

Q.7.8.4

R-MSG1 (supplements 10.7.6)

Table Q.14/G.992.1 – Assignment of 48 bits of R-MSG1
Parameter (Note 2)
Suffix(ces) of mi (Note 1)
47-18
Reserved for future use

17
Trellis coding option
16
Overlapped spectrum option (Note 3)
15
Unused (shall be set to "1")14
Support of S = 1/2 mode (see Q.4.9) (Note 4)
13
Support of dual latency downstream
12
Support of dual latency upstream
11
Network Timing Reference
10, 9
Framing mode
8-5
Reserved for future use
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
NOTE 3 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
NOTE 4 – Since the S=1/2 mode is mandatory for Annex Q, a modem supporting Annex Q shall set this bit to binaryONE.

Q.7.8.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.7.6.6)

The Nupmax (transmit) capability is encoded onto {m4 , ..., m0} with a conventional binary representation (e.g.
100012 = 17).
Q.7.9

Exchange – ATU-C (supplements 10.8)

During C-RATESn, C-MSGn, C-B&G, and C-CRCn, the ATU-C shall transmit the FEXTR symbol. In the other signals,
the ATU-C shall transmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), andshall not transmit the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The
duration of each state is defined in Figure Q.27.

- 118 -

Q.7.9.1

C-MSG2 (supplements 10.8.9)

Replace Table 10-13 with Table Q.15.

Table Q.15/G.992.1 – Assignment of 32 bits of C-MSG2
Suffix(ces) of mi (Note 1)

Parameter (Note 2)

31-26

Estimated average loop attenuation

25-21

Reserved for future use

20-16

Performance margin with selected rate option

15-11

Reserved for future use

10-0

Total number of bits supported

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
For NSCus=32,
n1C-MSG2 = 43
n2C-MSG2 = 91
Otherwise,
n1C-MSG2 = 139
n2C-MSG2 = 187
Q.7.9.1.1

Total number of bits per symbol supported (replaces 10.8.9.3)

The ATU-C receiver shall also calculate the maximum number of bits per symbol that the upstream channel can support−7

with the performance margin defined in C-MSG-RA at an error rate of 10 .
The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTC and
NEXTC downstream channel performance [e.g. if the maximum numbers of bits that can be supported in FEXTC and
NEXTC symbols are 111 and 88 {Total number of bits per symbol supported} = (111 x 126 + 88 x 214)/340 = 96]. This
number is encoded into bits 10-0 using a conventional binary representation [e.g. if the maximum number of bits thatcan be supported is 96 (data rate = 384 kbit/s), {m10, ..., m0} = 000011111112].
NOTE – The number of symbols per hyperframe is 340. The number of FEXT symbols is 126. The number of NEXTsymbols is 214.
Q.7.9.1.2

Estimated average upstream loop attenuation (supplements 10.8.9.1)

For Annex Q-EU, see A.3.2.

Q.7.9.2

C-B&G (replaces 10.8.13)

C-B&G shall be used to transmit to the ATU-R the bits and gains information, Bitmap-FC {b1, g1, b2, g2, ... bNSCus-1,
gNSCus-1}, and Bitmap-NC {bNSCus+1, gNSCus+1, bNSCus+2, gNSCus+2, ..., b2*NSCus-1, g2*NSCus-1}, that are
to be used on the upstream carriers. bi of Bitmap-FC indicates the number of bits to be coded by ATU-R transmitter
onto the i th upstream carrier in FEXTC symbols; gi of Bitmap-FC indicates the scale factor, relative to the gain thatwas used for that carrier during the transmission of R-MEDLEY, that shall be applied to the i th upstream carrier in
FEXTC symbols. Similarly, bi of Bitmap-NC indicates the number of bits onto the (i – NSCus) th upstream carrier in- 119 -

NEXTC symbols; gi of Bitmap-NC indicates the scale factor that shall be applied to the (i – NSCus) th upstream carrierin NEXTC symbols.
Because no bits or energy will be transmitted at DC or one-half the sampling rate, b0, g0, bNSCus, gNSCus, b2*NSCus,
and g2*NSCus are all presumed to be zero and shall not be transmitted.
Each bi shall be represented as an unsigned 5-bit integer, with valid bis lying in the range of zero to Nupmax, themaximum number of bits that the ATU-R is prepared to modulate onto any subcarrier, which is communicated in
R-MSG1.
Each gi shall be represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of
the third most significant bit. For example, a gi with binary representation (most significant bit listed first)
001.010000002 would instruct the ATU-R to scale the constellation for carrier i, by a gain factor of 1.25, so that thepower in that carrier shall be 1.94 dB higher than it was during R-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
Let NSCu=128, except when EU-32 is used where NSCu=32. The C-B&G information shall be mapped in a32*(NSCu-1)-bit [4*(NSCu-1) byte] message m defined by:
m = {m32*(NSCu-1)-1, m32(NSCu-1)-2, …, m1, m0} = { g2*NSCu-1, b2*NSCu-1, …, gNSCu+1, bNSCu+1,
gNSCu-1, bNSCu-1, …, g1, b1},
(C.10-2)
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in
4*(NSCu-1) FEXTR symbols. When NSCu=32, including C_CRC5, the total length is 336 symbols while for
NSCu=128, the total length is 336+3*345=1371 symbols, using the transmission method as described in 10.8.9.
When Bitmap-NC is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NC shall be set to zero.
For index between NSCus+1 and 127, the m values are set to 0.
Q.7.9.3

C-SEGUE3 (replaces 10.8.16)

The duration of C-SEGUE3 is 18 symbols. Following C-SEGUE3, the ATU-C completes the initialization and enters
C-SHOWTIME. In C-SHOWTIME, ATU-C shall transmit the signal using Bitmap-FR and Bitmap-NR with the sliding
window.
When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbols.

- 120 -

Q.7.9.4

C-RATES-RA (supplements 10.8.3)
Table Q.16/G.992.1 – RRSI fields of C-RATES-RA←⎯⎯⎯⎯⎯ bits ⎯⎯⎯⎯→
fields7

6

RSF

B10 (AS0)

0

5

4

3

2

1

value of RSF
MSB

RSI

B8 (AS0)LSB

B9 (AS0)

value of RSI
MSB

S

I9

LSB

I8

value of S
MSB

I

I7

I6

FS(LS2)

0

I5

LSB
I4

I3

I2

I1

I0

value of FS(LS2) set to {000000002}

The RSI field has been extended to include bit B9 of BI (AS0) in bit 6, and The RSF field has been extended to include
the most significant bit B10 of BI (AS0) in bit 7, BI (AS0) being the number of payload bytes in the AS0 bearer channel
in the downstream interleave buffer. This is to support the higher data rates for the S=1/4, S=1/6 and S=1/8 modes.
The S field shall be coded {1001002) to indicate S=1/4, {1001102} to indicate S=1/6, and {1010002) to indicate S=1/8.
For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7.10Exchange – ATU-R (supplements 10.9)

ATU-R shall transmit only the FEXTC symbols in R-MSGn, R-RATESn, R-B&G, R-CRCn. In other signals, the
ATU-R shall transmit both FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shallnot transmit NEXTC symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is definedin Figure Q.27.
Q.7.10.1

R-MSG-RA (supplements 10.9.2)

Replace Table 10-15 with Table Q.17.

- 121 -

Table Q.17/G.992.1 – Assignment of 80 bits of R-MSG-RA (Annex Q-EU)
Suffix(ces) of mi(Note)
79-72
71 - 70
69, 68
67-56

Parameter
All reserved bits shall be set to 0
Reserved for ITU-T
Extension to number of RS payload bytes, K
Extension to number of tones carrying data (ncloaded)
Bfast-max

55-49
48-40
39-32
31-25
24-21
20-16

Number of RS overhead bytes, (R)
Number of RS payload bytes, K
Number of tones carrying data (ncloaded)
Estimated average loop attenuation
Coding gain
Performance margin with selected rate option

15 - 14

Extension to total number of bits per DMT symbol, Bmax

13-12
11-0

Maximum Interleave Depth downstream
Total number of bits per DMT symbol, Bmax

NOTE – Within the separate fields the least significant bits have the lowest subscripts.

Q.7.10.1.1

Total number of bits supported (Bmax) (replaces 10.9.2.8)

This parameter shall be defined as in R-MSG2, see Q.7.9.1.
Q.7.10.1.2

Bfast-max (new)Bfast-max is the maximum number of bits of the fast buffer for fast data transmitted on the condition that the bits of thefast data can be equally assigned to all FEXT-symbols and NEXT-symbols.
Fast Buffered Data Bfast-max is tf.
Q.7.10.2

R-MSG2 ( supplements 10.9.8)

Table Q.18/G.992.1 – Assignment of 32 bits of R-MSG2
Suffix(ces) of mi (Note 1)
Parameter (Note 2)
31-25
Estimated average loop attenuation
24-21
Reserved for future use
20-16
Performance margin with selected rate option
15 - 14
13-12
11-0

Extension to total number of bits per DMT symbol, Bmax
Reserved for future use
Total number of bits per DMT symbol, Bmax

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
N1R-MSG2 = 10
N2R-MSG2 = 20
Q.7.10.2.1

Total number of bits per symbol supported (supplements 10.9.8.3)

The maximum number of bits per symbol that the downstream channel can support is encoded into bits 15, 14 and 11 –0.

- 122 -

The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTR and
NEXTR downstream channel performance. For example, if the maximum numbers of bits that can be supported in
FEXTR and NEXTR symbols are 111 and 88, the total number of bits per symbol supported is (111 x 126 + 88 x
214)/340 = 96.
NOTE – The number of symbols per hyperframe is 340, the number of FEXT symbols is 126, and the number of NEXTsymbols is 214.
Q.7.10.2.2 Estimated average downstream loop attenuation (supplements 10.9.8.1)
For Annex Q-EU, see A.3.3.
Q.7.10.3 R-REVERB5 (supplement of 10.9.12)
The duration of R-REVERB5 is 345n-40, 3<=n<=19, when NSCu=128, or 3<=n<=16 when NSCu=32.
Q.7.10.4

R-B&G (replaces 10.9.14)

The purpose of R-B&G is to transmit to ATU-C the bits and gains information, Bitmap-FR {b1, g1, b2, g2, ...,bNSCds-1, gNSCds-1}, and Bitmap-NR {bNSCds+1, gNSCds+1, bNSCds+2, gNSCds+2, ..., b2*NSCds-1,
g2*NSCds-1}, to be used on the downstream subcarriers. bi of Bitmap-FR indicates the number of bits to be coded by
ATU-C transmitter onto the i th downstream subcarrier in FEXTR symbols; gi of Bitmap-FR indicates the scale factor
that shall be applied to the i th downstream subcarrier in FEXTR symbols, relative to the gain that was used for thatcarrier during the transmission of C-MEDLEY. Similarly, bi of Bitmap-NR indicates the number of bits onto the (i –NSCds) th downstream carrier in NEXTR symbols; gi of Bitmap-NR indicates the scale factor that shall be applied tothe (i – NSCds) th downstream carrier in NEXTR symbols. Because no bits or energy will be transmitted at DC or
one-half the sampling rate, b0, g0, bNSCds, gNSCds, b2*NSCds, and g2*NSCds are all presumed to be zero, and are
not transmitted. When subcarrier 64 is reserved as the pilot tone, b64 and bNSCds+64, shall be set to 0, g64 andgNSCds+64 shall be set to gsync. When subcarrier 96 is reserved as the pilot tone, b96 and bNSCds+96, shall be set to0, g96 and gNSCds+96 shall be set to gsync. When subcarrier 128 is reserved as the pilot tone, b128 and bNSCds+128,
shall be set to 0, g128 and gNSCds+128 shall be set to gsync. When subcarrier 256 is reserved as the pilot tone, b256
and bNSCds+256, shall be set to 0, g256 and gNSCds+256 shall be set to gsync.The value gsync represents the gain
scaling applied to the sync symbol.
Each bi is represented as an unsigned 5-bit integer, with valid bi lying in the range of zero to Ndownmax, the maximum
number of bits that the ATU-C is prepared to modulate onto any subcarrier, which is communicated in C-MSG1.
Each gi is represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of thethird most significant bit. For example, a gi with binary representation (most significant bit listed first) 001.010000002
would instruct the ATU-C to scale the constellation for carrier i by a gain factor of 1.25, so that the power in that carrier
shall be 1.94 dB higher than it was during C-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
The R-B&G information shall be mapped in a (2*NSCds-2)*16-bit ((2*NSCds-2)*2 byte) message m defined by:
m = {m(2*NSCds-2)*16-1, m(2*NSCds-2)*16-2, …, m1, m0} = { g2*NSCds-1, b2*NSCds-1, …, g NSCds+1, b(Q.10-3)
NSCds+1, g NSCds-1, b NSCds-1, …, g1, b1},
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in(2*NSCds-2)*2 symbols, using the transmission method as described in 10.9.8.
When Bitmap-NR is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NR shall be set to zero.

- 123 -

Q.7.10.5

R-SEGUE5 (replaces 10.9.17)

The duration of R-SEGUE5 is 13 symbols. Following R-SEGUE-5, ATU-R completes the initialization and enters
R-SHOWTIME. In R-SHOWTIME, ATU-R shall transmit the signal using Bitmap-FC and Bitmap-NC with the sliding
window.
When Bitmap-NC is disabled (FEXT Bitmap mode), ATU-R shall not transmit NEXTC symbols.

- 124 -

ATU-CC-FLAG2(G.994.1)

C-GALF2(G.994.1)≥ 128≤ 2048C-QUIET2(Note 5)345n(n ≤ 38)

ATU-R

If R-ACK2then
C-PILOT1

If R-ACK1then
C-PILOT1AR-GALF2(G.994.1)

Beginning ofHyperframe

R-QUIET2≤ 15500

345n(1 ≤ n ≤ 33)≤ 32
Beginning ofHyperframe

1725

C-QUIET3A(Note 2)

R-FLAG2(G.994.1)

R-REVERB1
1536

C-REVERB1
12477(Note 5)9216

C-PILOT2(Note 4)

1536

C-ECT

(Note 2)

(Note 5)4608

C-REVERB2

1536

If R-ACK2 then C-PILOT3
If R-ACK1 then C-QUIET53628

C-REVERB3

20

C-SEGUE1

2884

C-RATES1/C-CRC1
C-MSG1/C-CRC2

Last symbol
may beshortened byn samples

R-QUIET3≥ 6144≤ 6145

R-ECT

1536

R-REVERB2≥ 3634≤ 3643

R-SEGUE1

5 ≤, ≤ 14(Note 2)

(Note 1)Introduction ofguard time

R-REVERB3
345n + 208(0 ≤ n ≤ 7)

49152
C-MEDLEY

345n - 13(9 ≤ n ≤ 16)
R-SEGUE2

13

R-RATES1/R-CRC1
R-MSG1/R-CRC2

1254

R-MEDLEY

49152(Note 3)(Note 2)

T1532900-99

Figure Q.26/G.992.1 – Timing diagram of the initialization sequence – Part 1- 125 -

(Note 4)NOTE 1 – The ATU-C shall transmit the FEXTR symbols, and shall not transmit as NEXTR symbols except the pilot
tone.
NOTE 2 – The ATU-C shall transmit both FEXTR and NEXTR symbols, when Bitmap-NR is enabled (Dual Bitmapmode). ATU-C shall not transmit the NEXTR symbols except pilot tone, when Bitmap-NR is disabled(FEXT Bitmap mode).
NOTE 3 – The ATU-R shall transmit the FEXTC symbols, and shall not transmit the NEXTC symbols.
NOTE 4 – The ATU-R shall transmit both FEXTC symbols, when Bitmap-NC is enabled (Dual Bitmap mode).
ATU-R shall not transmit NEXTC symbols, when Bitmap-NC is disabled (FEXT Bitmap mode).
NOTE 5 – The ATU-C shall transmit both FEXTR and NEXTR symbols.

- 126 -

Figure Q.27/G.992.1 – Timing diagram of the initialization sequence – Part 2[Editor’s note: updated Figure Q.27 to parameterize the length of C-B&G and the maximum length of R-REVERB5.]
Q.8

AOC On-line adaptation and reconfiguration (pertains to clause 11)

Q.8.1.1

Bit swap request (replaces 11.2.3)

The receiver shall initiate a bit swap by sending a bit swap request to the transmitter via the AOC channel. This request
tells the transmitter which subcarriers are to be modified. The format of the request is shown in Table Q.19.

Table Q.19/G.992.1 – Format of the bit swap request message
Message header{111111112}(8 bits)

Bitmap index(1 bit)Message field 1-4
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

The request shall comprise nine bytes as follows:• an AOC message header consisting of 8 binary ones;• message fields 1-4, each of which consists of a one-bit bitmap index, subchannel index bits 10 & 9, and a five-bit
command followed by bits 8 to 1 of the subchannel index. One-bit bitmap index, subchannel index bits 10 & 9,
and valid five-bit commands for the bit swap message shall be as shown in Table Q.20. In Table Q.20, the MSB
for the bit swap request command represents the Bitmap index. For downstream data, Bitmap index equals 0
indicates Bitmap-FR, and Bitmap index equals 1 indicates Bitmap-NR. Similarly for upstream data, Bitmap
index equals 0 indicates Bitmap-FC, and 1 indicates Bitmap-NC. The next 2 bits are subchannel index bits 10 &9. The ten-bit subchannel index is counted from low to high frequencies with the lowest frequency subcarrier
having the number zero. The subcarrier index zero shall not be used;• the bit swap between FEXTC/R symbols and NEXTC/R symbols is not allowed.

Table Q.20/G.992.1 – Bit swap request commandValue(8 bit)yzz000002

Interpretation
Do nothing

yzz000012
yzz000102

Increase the number of allocated bits by one

yzz000112
yzz001002

Increase the transmitted power by 1 dB

yzz001012
yzz001102

Increase the transmitted power by 3 dB

yzz001112
yzz01xxx2

Reduce the transmitted power by 2 dB

Decrease the number of allocated bits by one
Increase the transmitted power by 2 dB
Reduce the transmitted power by 1 dB
Reserved for vendor discretionary commands

NOTE – y is "0" for FEXTC/R symbols, and "1" for NEXTC/R symbols of the Sliding Window.
NOTE – subchannel index = zz2*256 + subchannel index value from lower 8 bit field
The bit swap request message (i.e. header and message fields) shall be transmitted five consecutive times.
To avoid gi divergence between ATU-C and ATU-R after several bit swaps, for a gi update of ∆ dB the new gi value
should be given by:- 127 -

g i ' = (1 / 256) × round (256 × g i × 10 exp(∆ / 20))
Q.8.1.2(Q.11-1)

Extended bit swap request (supplements 11.2.4)

The format of the extended bit swap request is shown in Table Q.21.

Table Q.21/G.992.1 – Format of the bit swap request message
Message header{111111002}(8 bits)

Bitmap index(1 bit)Message field 1-6
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

In the same manner as the bit swap request, each of the message fields of the extended bit swap request consists of
one-bit bitmap index, a five-bit command followed by a related ten-bit subchannel index.
Q.8.1.3

Bit swap acknowledge (supplements 11.2.5)

The bit swap superframe counter number shall only indicate the last superframe (SPF#4) of a hyperframe.
The new bit and/or transmit power table(s) shall then take effect starting from the first frame (frame 0) of SPF#0 of a
hyperframe.
If the bit swap superframe counter number contained in the received bit swap acknowledge message does not indicate
SPF#4, then the new table(s) shall take effect starting from frame 0 of SPF#0 of the next hyperframe.
Q.9

POTS splitter

For operation according to G.992.1 Annex Q-EU, the Annex E.4/G.992.3 requirements applying over a frequency band
up to 1104 kHz, shall be met over a frequency band up to 3750 kHz.

- 128 -

資料３
G.992.1 ANNEX Q-EU (REVISION 4S.0)
PROPRIETARY EXTENSION TO G.992.1 ANNEX I

This document defines G.992.1 Annex Q-EU (Quad spectrum downstream with extended upstream spectrum), a
proprietary extension to G.992.1 Annex I to extend the data rate beyond 32 Mbit/s downstream and 4 Mbit/s upstream
on short loops by way of:• Increased downstream bandwidth Æ increased number of subcarriers, NSCds=1024 (used subcarriers up to869)• Increase upstream bandwidth Æ increased number of subcarriers, NSCus=96• Increased bit loading, beyond 15 bits/bin• Extended framing Æ S=1/2n, with support for n = 1 to 4
Due to the increase in upstream data rates, the upstream maximum interleave depth has been increased to 16. Support ofthis is mandatory.
The attached text is the approved text for Annex I, marked up with revision control to show the changes necessary tosupport the additional functionality.
Revision R4 has the following changes with respect to Revision R3.2:• modified and upstream PSDs. Added EU-S68 to S96•• added G.994.1 code points to support above changes- 129 -

ANNEX Q-EU
Specific requirements for an ADSL system to support downstream data rates greater than 32 Mbit/s andupstream data rates greater than 4 Mbit/s on short loops operating in the same cable as ISDN as defined in
ITU-T Recommendation G.961 Appendix III

Q.1

Scope

This annex describes those specifications that are unique to an ADSL system coexisting in the same binder as
TCM-ISDN as defined Recommendation G.961 Appendix III. The subclauses in this annex provide supplementary andreplacement material to the clauses in the main body. The nature of the material is parenthetically indicated in the
subclause heading. The modifications described in this annex allow a performance improvement from the ADSL system
specified in Annex C for short loops in an environment coexisting with TCM-ISDN in the same cable. Specifically, thisAnnex specifies extensions to downstream and upstream bandwidth, framing modes, and maximum bit loading tosupport downstream data rates greater than 32 Mbit/s and upstream data rates greater than 4 Mbit/s. This annex also
defines those parameters of this ADSL system that have been left undefined in the main body of this Recommendation.
An ADSL system implementing Annex Q-EU shall support Annex Q. It is recommended that an ADSL system
implementing Annex Q-EU also implements Annexes I and C.
Q.2

Definitions

Bitmap-FC
Bitmap-FR
Bitmap-NC
Bitmap-NR
Dual Bitmap
FEXT Bitmap
FEXTC duration
FEXTC symbol
FEXTR duration
FEXTR symbol
Hyperframe
NEXTC duration
NEXTC symbol
NEXTR duration
NEXTR symbol
NSCds

NSCus
NSWF
Subframe
TTR
TTRC
TTRR
UI

ATU-R transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-R
ATU-R transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-R
The Dual Bitmap method has dual bit rates under the FEXT and NEXT noise from TCM-ISDN
Similar to the Dual Bitmap method however transmission only occurs during FEXT noise fromTCM-ISDN
TCM-ISDN FEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN FEXTTCM-ISDN FEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN FEXT
5 Superframes structure which synchronized TTR
TCM-ISDN NEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN NEXT
TCM-ISDN NEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN NEXT
The highest subcarrier index that can be used for downstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCds = 256 for a downstream
channel using the frequency band up to 1.104MHz; NSCds = 512 for a downstream channel
using the frequency band up to 2.208MHz.
The highest subcarrier index that can be used for upstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCus = 64 for an upstream
channel using the frequency band up to 276 kHz.
Sliding Window frame counter10 consecutive DMT symbols (except for sync symbols) according to TTR timing
TCM-ISDN Timing Reference
Timing reference used in ATU-C
Timing reference used in ATU-R
Unit Interval- 130 -

Q.3

Reference Models

Q.3.1

ATU-C transmitter reference model (replaces figures in 5.1)

See Figure Q.1 and Figure Q.2.
"Bits""Bits" &"Gains"
2*NSCds-1

AS0
AS1
AS2
AS3
LS0
LS1
LS2
NTR

crcf
Mux/
Sync
Control

crci

scram
&
FEC

scram
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

2*NSCds-2
480
IDFT

OutputParallel/
SerialBuffer

1
n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to NSCds-1
Constellation
Encoder Input
Data Frame

U-C

T1532760-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure Q.1/G.992.1 – ATU-C transmitter reference model for STM transport
Annex Q-EU does not currently support STM transport. It only supports ATM transport.

- 131 -

"Bits""Bits" &"Gains"
2*NSCds-1

AS0
ATM0

Cell TC
crcf

AS1
ATM1

Cell TC

NTR

Mux/
Sync
Control
crci

scram
&
FEC

scram
&
FEC

Rate
converterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

2*NSCds-2
480
IDFT
1

OutputParallel/
SerialBuffer

n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to NSCds-1
Constellation
Encoder Input
Data Frame

U-C

T1532770-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure Q.2/G.992.1 – ATU-C transmitter reference model for ATM transport- 132 -

Q.3.2

ATU-R transmitter reference model (replaces figures in 5.2)

See Figure Q.3 and Figure Q.4.

"Bits""Bits" &"Gains"LS02*NSCus-1
crcf

LS0
LS1

Mux/
Sync
ControlLS2

crci

scrambler&
FEC

scrambler
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

2*NSCus-2
59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR

B
FEC Output
Data Frame

Zi
i=1 to NSCus-1
C
Constellation
Encoder Input
Data Frame

U-R

T1532780-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (1.104 MHz).

Figure Q.3/G.992.1 – ATU-R transmitter reference model for STM transport
Annex Q-EU does not currently support STM transport. It only supports ATM transport.

- 133 -

"Bits"

2*NSCus-1

LS0
Cell TC

ATM0

LS1Cell TC

ATM1"Bits" &"Gains"

crcf
Mux/
Sync
Control
crci

scrambler&
FEC

scrambler&
FEC

2*NSCus-2

RateconverterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR
B
FEC Output
Data FrameZi
C
i=1 to NSCus-1
Constellation
Encoder Input
Data Frame

U-R

T1532790-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (1.104 MHz).

Figure Q.4/G.992.1 – ATU-R transmitter reference model for ATM transport- 134 -

Q.3.3

ATU-C/R transmitter timing model (replacement for 5.3)

Q.3.3.1

TCM-ISDN crosstalk timing model (new)Figure Q.5 shows the timing chart of the crosstalk from TCM-ISDN.

TTR
377 UI
receive ISDN

transmit ISDNCO

0 ≤ propagation delay ≤ 16 UI
RT

6-7.5 UI

377 UI

receive ISDN

transmit ISDN

FEXTR

NEXTR

SC
TTRC

ATU-C TX

Frame Frame0 ≤ propagation delay ≤ 18.5 UI

Received
TTRC

SR

TTRR
NEXTC
ATU-R TXFEXTC

Frame Frame
T1532800-99

1 UI = 3.125 µs
FEXTR and NEXTR are estimated by ATU-CFEXTC and NEXTC are estimated by ATU-R

TTR

TCM-ISDN timing reference

TTRC

Timing reference used in ATU-C

Received TTR C Received TTRC at ATU-R
TTRRTiming reference used in ATU-R

SC

55 × 0.9058 µs: Offset from TTR to TTRC

SR

–42 × 0.9058 µs: Offset from received TTRC to TTRR

Figure Q.5/G.992.1 – Timing chart of the TCM-ISDN crosstalk

The data stream of TCM-ISDN is transmitted in TTR period. CO transmits the stream in the first half of the TTR period
and RT transmits in the second half of the TTR period. ATU-C receives NEXT noise from the ISDN in the first half of
the TTR period and FEXT noise from the ISDN in the second half of the TCM-ISDN period. On the other hand,
ATU-R receives FEXT noise from the ISDN in the first half of the TTR period and NEXT noise from the ISDN in thesecond half of the TTR period.

- 135 -

As defined in Q.7.6.2 and Q.7.8.3, the ATU-C shall estimate the FEXTR and NEXTR duration at ATU-R, and the
ATU-R shall estimate FEXTC and NEXTC duration at ATU-C taking propagation delay on the subscribe line into
consideration.
The ATU-C shall transmit any symbols by synchronizing with the TTRC. The ATU-R shall transmit any symbols
synchronizing with the TTRR generated from received TTRC.
Q.3.3.2

Sliding window (new)Figure Q.6 shows the timing chart of the transmission for the Annex Q-EU downstream at ATU-C.
Hyperframe = 345 symbols

TTRC
Crosstalk
period

FEXTR

FEXTR

FEXTR

FEXTR
NEXTR

NEXTR

ATU-C
T Frame
SWB
T1532810-99

FEXTR symbol
NEXTR symbol

Sliding Window

Figure Q.6/G.992.1 – Sliding window for downstream symbols

The Sliding Window defines the transmission symbols under the crosstalk noise environment synchronized to theperiod of TTR. The FEXTC/R symbol represents the symbol completely inside the FEXTC/R duration. The NEXTC/R
symbol represents any symbol containing the NEXTC/R duration. Thus, there are more NEXTC/R symbols than
FEXTC/R symbols.
The ATU-C decides which transmission symbol is FEXTR or NEXTR symbol according to the sliding window andtransmits it with the corresponding bit table. Similarly, the ATU-R decides the transmission symbol is a FEXTC or
NEXTC and transmits it with the corresponding bit table. Although the phase of the sliding window is asynchronouswith TTRC/R, the pattern is fixed to the 345 frames of the hyperframe.
Q.3.3.3

ATU-C Symbol Synchronization to TTR (new)345 symbols are 34 cycles with cyclic prefix of TTRC (or 32 cycles of TTRC without cyclic prefix). This implies a PLL
lock at the ATU-R.
Q.3.3.4

Dual Bitmap switching (new)The ATU-C transmits FEXTR symbols using Bitmap-FR (in FEXTR duration), and transmits NEXTR symbols using
Bitmap-NR (in NEXTR duration) according to the result of initialization. The ATU-R transmits FEXTC symbols using
Bitmap-FC (in FEXTC duration), and transmits NEXTC symbols using Bitmap-NC (in NEXTC duration) in the samemanner.
The ATU-C shall have the capability to disable Bitmap-NC and Bitmap-NR (see Q.4.5 and Q.5.3).

- 136 -

Q.3.3.5

Loop timing at ATU-R (new)The phase relation between received symbol and transmitted symbol of ATU-R at the reference point U-R shall meetthe phase tolerances as shown in Figure Q.7.
(point U-R)
ATU-R receive
DMT symbol

ATU-R transmit
DMT symbol
T1532820-99±4.5 µs + SR

Figure Q.7/G.992.1 – Loop timing for ATU-R

Q.4

ATU-C functional characteristics (pertains to clause 7)

Q.4.1

STM transmission protocols specific functionality (pertains to 7.1)

Q.4.1.1

ATU-C input and output V interface for STM transport (replaces figure in 7.1.1)

See Figure Q.8.

- 137 -

AS0 (n0 × 32 kbit/s)
AS1 (n1 × 32 kbit/s)
AS2 (n2 × 32 kbit/s)
AS3 (n3 × 32 kbit/s)
Digital
Network

twisted pair

LS0 ("C"; 16 or m0 × 32 kbit/s)

ATU-C

LS1 (m1 × 32 kbit/s)
LS2 (m2 × 32 kbit/s)
NTR
TTR
Operations, maintenance and control

T1532830-99

V-C
NOTE 1 – Optional bearer channels (both duplex and simplex) and features are shown with dotted lines.
NOTE 2 – TTR may be generated in the ATU-C without being provided from the V-C reference point.

Figure Q.8/G.992.1 – ATU-C functional interfaces for STM transport at the V-C reference point

Q.4.1.2

Payload transfer delay (supplements 7.1.4)

Since Annex Q-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.1.4.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
Q.4.2
Q.4.2.1

ATM transmission protocols specific functionalities (pertains to 7.2)
ATU-C Input and Output V interface for ATM transport (replaces figure in 7.2.1)

See Figure Q.9.

- 138 -

ATM layer

ATM0
Tx_ATM0P
O
RT0

Tx_Cell_Handshake0
Rx_ATM0
Rx_Cell_Handshake0

ATM1
P
O
R
T
1

Twisted pair

Tx_ATM1
ATU-C
Tx_Cell_Handshake1
Rx_ATM1
Rx_Cell_Handshake1
NTR

and interface to
Digital network

TTR
Operations, administration,
maintenance and control
V-C

T1532840-99

NOTE – TTR can be generated in the ATU-C without being provided from the V-C reference point.

Figure Q.9/G.992.1 – ATU-C functional interfaces to the ATM layer at the V-C reference point

Q.4.2.2

Payload transfer delay (supplements 7.2.2)

Since Annex Q-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.2.2.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
Q.4.3
Q.4.3.1

Framing (pertains to 7.4)
Superframe structure (supplements 7.4.1.1)

Since the rate converter reorders the user data and overhead bit-level data to create hyperframes, the input data frames
to the constellation encoder are different than those defined in 7.4.1.1.
Q.4.3.2

Hyperframe structure (replaces 7.4.1.3)

Annex Q-EU uses the hyperframe structure shown in Figure Q.10. Figure Q.10 shows the phase relationship between
the TTRC and the hyperframe at the point U-C. Each hyperframe is composed of 5 superframes, which are numberedfrom 0 to 4. In order to indicate the boundary of the hyperframe, the inverse synch symbol is used for the 4thsuperframe (SPF#3), which is generated from a tone-by-tone 180-degree phase reversal of the synchronization symbol(see Q.4.7.1) except for the pilot tone.
The bit-level data stream from the rate-converter is extracted according to the size of Bitmap-FR and Bitmap-NR using
the Sliding Window (see Q.3.3.2).
In order to make the bit rate to be a multiple of 32 kbit/s, the dummy bits are inserted at the end of hyperframe by the- 139 -

rate converter (see Q.4.4.2). The hyperframe is composed of 345 DMT symbols, numbered from 0 to 344. Each symbol
is assigned as FEXTR or NEXTR symbol in a FEXTR or NEXTR duration (see Q.2), and the following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-C transmitter (see Figure Q.11).
For Ndmt = 0, 1, ..., 344

S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > a + b) }elsethen FEXTR symbol
then NEXTR symbol

where a = 1243, b = 1461
Thus, 128 DMT symbols are allocated in the FEXTR duration, and 217 DMT symbols are allocated in the NEXTR
duration. The symbols are composed of:
FEXTR symbol:
Number of symbol using Bitmap-FR
Number of synch symbol
Number of inverse synch symbol
NEXTR symbol:

= 126
=1
=1

Number of symbol using Bitmap-NR= 214

Number of synch symbol=3

During FEXT Bitmap mode, the ATU-C shall transmit only the pilot tone in NEXTR symbols.

- 140 -

5 Superframe (= 340 frames)(point B)
1 Superframe = 68 frames (17 ms)

1 frame = 250 µs
Rate-Converter(point U-C, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#27

TC#33

TTR
ATU-R
Crosstalk

NEXT

FEXT

FEXT

Hyperframe = 345 symbols (85 ms)
SPF#1

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol F F F F N N N N N N F F

SSliding window

SPF#2
S

S

SPF#3
N F I

Inverse synch symbol

S

NEXTR Synch symbol

F

Symbol using Bitmap-FR (FEXTR duration bitmap)

N

Symbol using Bitmap-NR (NEXTR duration bitmap)

S

FEXTR Synch symbol

Figure Q.10/G.992.1 – Hyperframe structure for downstream- 141 -SPF#4
F F

FEXTR duration

1 symbol = 246 µs
I

NEXT

N
T1532850-99

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

0
10
20
30

1

2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
21
22
23
24
25
26
27
28
29
40
31
32
33
34
35
36
37
38
39
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
SS
61
62
63
64
65
66
67
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100 101
101 102
103
104
105
106
107
108
109
110 111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
SS
132
133
134
135
136
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162 163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181 182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
SS
203
204
205
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233 234
235
236
237
238
239
240
241
242 243
253
244
245
246
247
248
249
250
251
252
263
254
255
256
257
258
259
260
260
262
264
265
266
267
268
269
270
271
272
273
274
276
277
278
279
280
281
282
283
ISS
284
285
286
287
288
289
290
291
292
293
295
296
297
298
299
300
301
302
303
294
304 305
306
307
308
309
310
311
312
313 314
315
316
317
318
319
320
321
322
323
324
334
325
326
327
328
329
330
331
332
333
SS
335
336
337
338
339
340
341
342
343
ISS

Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol
NEXTR data symbol

SS

NEXTR synch symbol
T1535330-00

Figure Q.11/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Downstream

Q.4.3.3

Subframe Structure (replaces 7.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table Q.1. The 34 subframes forma hyperframe.

- 142 -

Table Q.1/G.992.1 – Subframe (downstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

Q.4.3.4

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Inverse Synch Symbol#344 is Synch Symbol

Reduced overhead framing with merged fast and sync bytes (modifies 7.4.3.2)

In S=1/2n framing mode (see §Q.4.9), there are n Sync bytes per symbol time. The contents of the Sync bytes is thesame as in regular framing except that it repeats at n times the rate causing the superframe to be 68/n symbols in length.
The contents of the sync bytes are shown in Table 7-6/G.992.1. In S=1/2n framing mode, “Frame Number” in column 1
in Table 7-6/G.992.1 is replaced by “Sync Byte Index Number”.
As a result of the increase in superframe rate, the superframe contents is carried more frequently. For the case when
N=2, the EOC and AOC bandwidth doubles, thereby transferring actual messages at twice the rate. The CRC byte iscarried twice as frequently and therefore the maximum error rate rises from just over 58 per second to 117 per second.
Where the duration of an error condition is measured, this needs to be taken into consideration. The indicator bits arealso sent twice as often, which needs to be taken into consideration for statistics collection.
Q.4.4

Dual Bitmapping and Rate Conversion (replaces 7.15)

The functions of the rate converter (see Q.4.4.2), tone ordering (see Q.4.6), constellation encoding, and gain scaling
shall use one of two bitmaps stored in the ATU. This method is called the dual bitmap.

- 143 -

Q.4.4.1

Dual Bitmap (new)The Dual Bitmap method has individual bit rates under the FEXT and NEXT noise, and this needs an additional bit andgain table, {bi, gi}, and ordered bit table, b'i, for the tone ordering. The dual bitmaps are switched synchronized withthe sliding window pattern of NEXT/FEXT symbols. The number of bits and the relative gains to be used for every tone
are calculated in the bit loading algorithm during the initialization sequence, and transmitted in R-B&G.
Q.4.4.2

Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FR, Bitmap-NR and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amount of fast and interleaved data in Bitmap-FR and Bitmap-NR shall be calculated with thefollowing formulae and illustrated in Figure Q.12:
If tRf ≤ nRmax:n Rf = t Rf
nRi = nR − nRf
f Rf = t Rf
f Ri = f R − f Rf
If tRf > nRmax:

nRf = nR max

nRi = 0⎧⎡ t Rf × 10 − nRf × 6 ⎤⎪ f Rf 4 = ⎢
⎥
4
⎢
⎥
⎪
f Rf = ⎨⎡ t Rf ×10 − nRf × 7 ⎤⎪⎥⎪ f Rf 3 = ⎢3⎢⎥⎩⎧⎪ f Ri 4 = f R = f Rf 4
f Ri = ⎨⎪⎩ f Ri3 = f R − f Rf 3
Where:
tRf
tRi
fRf and nRf
fRf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FR and Bitmap-NR, respectively.
is the number of fast bits in Bitmap-FR if the subframe (see Q.4.3.3) contains 3 Bitmap-FR except
for synch symbols.
fRf4
is the number of fast bits in Bitmap-FR if the subframe contains 4 Bitmap-FR except for synch
symbols.
fRi and nRi
are the numbers of interleaved bits in Bitmap-FR and Bitmap-NR, respectively.
nR
is the number of total bits in Bitmap-NR, which is specified in the B&G tables.
During FEXT Bitmap mode, nRf and nRi are zero.
To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tRf ≤ nRmax:- 144 -

dummy Rf = 0

dummy Ri = ( f Ri × 126 + nRi × 214) − t Ri × 340

If tRf > nRmax:()
dummy Rf 3 = ( f Rf × 3 + nRf × 7 ) − t Rf × 10

dummy Rf 4 = f Rf × 4 + nRf × 6 − t Rf ×10

dummy Ri = ( f Ri 4 × 96 + f Ri3 × 30 ) − t Ri × 340

If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FR constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:

dummy SRf = f Rf 3 − f Rf 4
The receiver shall determine Bitmap-FR and Bitmap-NR so that dummyRi is less than 126, dummyRf4 is less than 4 anddummyRf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.

- 145 -

#335#336#337#338#339#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25 #26 #27 #28 #29

tRi

Interleaved DatatRj

Fast Data

NOTE – Bit Ordering:
The earlier bit is located at the bottom
each symbol in this figure.
Rate Converter

Order

When tRf ≤ nRmax

fRi =fR – fRf

fR#4 #5 #6 #7 #8 #9

dummyRi#21 #22 #23#10 #11 #12 #13#0 #1 #2 #3#14 #15 #16 #17 #18 #19 #20#343#339#340#341#342#24 #25 #26 #27 #28 #29

nRinnRf=tRf R

fRf – tRf
FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe

When tRf > nRmax#0 #1 #2 #3#21 #22 #23#10 #11 #12 #13

dummyRi

fRi3

fRi4
dummyRf4

fR#335#336#337#338

dummyRf4

dummyRf3

dummy Rf4

fRf3
fRf4

#4 #5 #6 #7 #8 #9#14#15 #16 #17#18 #19 #20#26 #27 #28 #29#339#340#341#342#343

nRf = n
FEXTNEXT
Symbols Symbols
Subframe

FEXT
Symbols

NEXT
Symbols

Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe
T1532860-99

Figure Q.12/G.992.1 – Bit distribution for Rate Converter under Dual latency and Dual Bitmap mode

Q.4.5

FEXT Bitmapping (replaces 7.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (Q.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures Q.10 and Q.16).
Annex Q-EU does not support the FEXT Bitmapping mode.
Q.4.6

Tone Ordering (replacement for 7.7)

A DMT time-domain signal has a high peak-to-average ratio (its amplitude distribution is almost Gaussian), and large
values may be clipped by the digital-to-analogue converter. The error signal caused by clipping can be considered as anadditive negative impulse for the time sample that was clipped. The clipping error power is almost equally distributed
across all tones in the symbol in which clipping occurs. Clipping is therefore most likely to cause errors on those tones- 146 -

that, in anticipation of a higher received SNR, have been assigned the largest number of bits (and therefore have thedensest constellations). These occasional errors can be reliably corrected by the FEC coding if the tones with the largest
number of bits have been assigned to the interleave buffer.
The numbers of bits and the relative gains in two bitmaps to be used for every tone are calculated in ATU-R receiver,and sent back to ATU-C according to a defined protocol (see 10.9.14). The pairs of numbers are typically stored, in
ascending order of frequency or tone numbers i, in bit and gain tables for Bitmap-FR and Bitmap-NR.
For Bitmap-FR, the "tone-ordered" encoding shall first assign fRf bits from the rate converter (see Q.4.4.2) to the tones
with the smallest number of bits assigned to them, and the remaining fRi bits to the remaining tones. For Bitmap-NR, it
shall first assign nRf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nRi bits to the remaining tones.
All tones shall be encoded with the number of bits assigned to them; one tone in each bitmap may therefore have a
mixture of bits from the fast and interleaved buffers.
The ordered bit tables b'iF and b'iN shall be based on the original bit tables biF and biN as follows:
For k = 0 to Ndownmax {From the bit table, find the set of all i with the number of bits per tone bi = k
Assign bi to the ordered bit allocation table in ascending order of i}
Two ordered bit tables for Bitmap-FR and Bitmap-NR shall be prepared. A complementary de-ordering procedure
should be performed in ATU-R receiver. It is not necessary, however, to send the results of the ordering process to thereceiver because the bit tables FR and NR were originally generated in ATU-R, and therefore those tables have all theinformation necessary to perform the de-ordering.
Q.4.7
Q.4.7.1

Modulation (pertains to 7.11)
Inverse Synchronization Symbol (replaces 7.11.4)

Except for the pilot tone, Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phasereversal of Synchronization symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
Q.4.7.2

Data subcarriers (modifies 7.11.1.1)

The channel analysis signal defined in 10.6.6 allows for a maximum of NSCds-1 carriers (at frequencies n∆f , n = 1 to
NSCds-1) to be used.
Q.4.7.3

Nyquist frequency (modifies 7.11.1.3)

The carrier at the Nyquist frequency (#NSCds) shall not be used for user data and shall be real valued; other possible
uses are for further study.
Q.4.7.4

Modulation by the inverse discrete Fourier transform (replaces 7.11.2)

The modulating transform defines the relationship between the 2*NSCds real values xn and the Zi:

xn =2* NSCds −1⎛ jπni ⎞∑ exp⎜⎝ NSCds ⎟⎠Zi =0i

for n = 0 to 2 * NSC − 1(7-21)The value of NSCds shall be 1024 for this Annex. However, the highest used subcarrier index shall be limited to 869.
The constellation encoder and gain scaling generate only NSCds-1 complex values of Zi. In order to generate realvalues of xn, the input values (NSCds-1 complex values plus zero at DC and one real value for Nyquist if used) shall beaugmented so that the vector Z has Hermitian symmetry. That is,- 147 -

Zi = conj (Z'2*NSCds-i)
Q.4.7.5

for i = NSCds+1 to 2*NSCds-1(7-22)

Synchronization symbol (modifies 7.11.3)

The synchronization symbol permits recovery of the frame boundary after micro-interruptions that might otherwise
force retraining.
The data symbol rate, fsymb = 4 kHz, the carrier separation, ∆f = 4.3125 kHz, and the IDFT size, N = 2*NSCds, aresuch that a cyclic prefix of 15.625%*NSCds samples could be used. That is, when NSCds = 256, there are 40 samples
in the cyclic prefix.
(512 + 40) × 4.0 = 512 × 4.3125 = 2208

(7-23)

The cyclic prefix shall, however, be shortened to 12.5%*NSCds samples, and a synchronization symbol (with anominal length of NSCds*2.125 samples) is inserted after every 68 data symbols. That is,(2 + 0.125)*NSCds × 69 = (2 + 0.15625)*NSCds × 68(7-24)
The data pattern used in the synchronization symbol shall be the pseudo-random sequence PRD, (dn, for n = 1 to
2*NSCds) defined by:
dn = 1for n = 1 to 9
(7-25)
dn = dn-4 ⊕ dn-9

for n =10 to 2*NSCds(7-26)

The first pair of bits (d1 and d2) shall be used for the DC and Nyquist subcarriers (the power assigned to them is zero,so the bits are effectively ignored); the first and second bits of subsequent pairs are then used to define the Xi and Yi for
i = 1 to NSCds-1 as shown in Table 7-13.
The period of the PRD is only 511 bits, so dn+511 is equal to dn. The d1-d9 shall be re-initialized for eachsynchronization symbol, so each symbol uses the same data.
The two bits that modulate the pilot carrier, shall be overwritten by {0,0}: generating the {+,+} constellation.
The minimum set of subcarriers to be used is the set used for data transmission (i.e. those for which bi > 0); subcarriers

for which bi = 0 may be used at a reduced PSD as defined in transmit PSD paragraphs of Annexes A, B and C. The data
modulated onto each subcarrier shall be as defined above; it shall not depend on which subcarriers are used.
Q.4.7.6

Cyclic prefix (replaces 7.12)

The last 12.5%*NSCds samples of the output of the IDFT (xn for n = 2*NSCds-0.125*NSCds to 2*NSCds-1) shall be
prepended to the block of 2*NSCds samples and read out to the digital-to-analogue converter (DAC) in sequence. For
example, when NSCds=256, the subscripts, n, of the DAC samples in sequence are 480 ... 511, 0 ... 511.
The cyclic prefix shall be used for all symbols beginning with the C-RATES1 segment of the initialization sequence, as
defined in 10.6.2.
Q.4.8

ATU-C Downstream transmit spectral masks (replaces 7.14)

The downstream spectral masks of Annex Q-EU are as specified in this section. When C-MSG1 bit 16 is 0, the PSD
mask as specified in § Q.4.8.1 shall be used. When C-MSG1 bit 16 is 1, the PSD mask as specified in § Q.4.8.2 shall be
used.
Q.4.8.1

Downstream non-overlapped PSD mask definition

The non-overlapped PSD masks are defined with absolute peak values in Figure Q.13. The low frequency stop band isdefined for frequencies below f1 kHz (tone n1); the high frequency stop band is defined at frequencies greater than3750 kHz (tone 869). The in-band region of these PSD masks is the frequency band from f1 kHz to 3750 kHz.

- 148 -

–18 dB/octave

PSD indBm/Hz–2.9 dB/octave–36.5 dBm/Hz peak PSD

36 dB/octave–44.2 dBm/Hz–357 dBm/Hz–100 dBm/Hz peak PSD
in 10 kHz window–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 3925 kHz–50 dBm/Hz–76.5 dBm/Hz–92.5 dBm/Hz–110 dBm/Hz
0

4

f3

f1

1104

3750
3925 4545

1622

Frequency band f (kHz)0<f<4
4 < f < f3
f3 < f < f1
f1 < f < 1104
1104 < f < 1622
1622 < f < 3750

Equation for line (dBm/Hz)
-97.5
-92.5
-92.5 + 36*log2(f/f3)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 2.9*log2(f/1622)

3750 < f < 3925
3925 < f < 12000-76.5 - 357*log2(f/3750)-100

Frequency (kHz)04
4

PSD level (dBm/Hz)
-97.5
-97.5
-92.5

Measurement BW
100 Hz100 Hz100 Hz

f3
f1
f1
1104
1622

-92.5
-44.2
-36.5
-36.5
-46.5

10 kHz
10 kHz
10 kHz
10 kHz
10 kHz3750
3750
3925 – 12000

-50
-76.5
-100

10 kHz
10 kHz
10 kHz- 149 -

–112 dBm/Hz

7225

12000

Frequency
in kHzAdditionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
3925
4545
7225
12000

PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

The corner frequencies f1 and f3 depend on the associated upstream PSD mask used, see §Q.5.6) and are defined asfollows:
Mask designator(DS-mm)
DS-32
DS-36
DS-40
DS-44
DS-48
DS-52
DS-56
DS-60
DS-64
DS-68
DS-72
DS-76
DS-80
DS-84
DS-88
DS-92
DS-96
NOTE 1 –NOTE 2 –NOTE 3 –NOTE 4 –NOTE 5 –NOTE 6 –Associatedupstream mask
EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64
EU-S68
EU-S72EU-S76
EU-S80EU-S84
EU-S88
EU-S92EU-S96

f1 (kHz)f3 (kHz)138
155.25172.5
189.75207
224.25241.5
258.75276
293.25310.5
327.75345
362.25379.5
396.75
414

54.45
61.26
68.06
74.87
81.67
88.48
95.29
102.09108.9115.71122.51129.32
136.12142.93149.74156.54163.35All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint withfrequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued
the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that
this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.
Figure Q.13: Non-overlapped Downstream Channel PSD Masks

Spectral Shaping of the In-Band Region defined in Q.4.8.3 and Transmit Signals with Limited Transmit Power definedin Q.4.8.4 shall be applied.

Q.4.8.2

Downstream Overlapped PSD mask definition

The overlapped PSD mask is defined with absolute peak values in Figure Q.14. The low frequency stop band is definedfor frequencies below 25.875 kHz (tone 6); the high frequency stop band is defined at frequencies greater than3750 kHz (tone 869). The in-band region of this PSD mask is the frequency band from 25.875 kHz to 3750 kHz.

- 150 -

–18 dB/octave

PSD indBm/Hz–36.5 dBm/Hz peak PSD–2.9 dB/octave–50 dBm/Hz

21 dB/octave–357 dBm/octave–100 dBm/Hz peak PSD
in 10 kHz window–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 3925 kHz–76.5 dBm/Hz–92.5 dBm/Hz–110 dBm/Hz
0425.8751104

3750
3925 4545

1622

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < 1104
1104 < f < 1622
1622 < f < 3750

Equation for line (dBm/Hz)-97.5-92.5 + 21*log2(f/4)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 2.9*log2(f/1622)

3750 < f < 3925
3925 < f < 12000-76.5 - 357*log2(f/3750)
-100

7225

Frequency (kHz)04
4
1025.8751104
1622

PSD level (dBm/Hz)
-97.5
-97.5
-92.5
interpolated
-36.5
-36.5
-46.5

Measurement Bandwidth
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz3750
3750
3925 – 12000

-50.0
-76.5
-100

10 kHz
10 kHz
10 kHz

Additionally, the PSD mask shall be satisfying following requirements:
Frequency (kHz)
3925
4545
7225
12000

PSD level (dBm/Hz)
-100
-110
-112
-112

- 151 -

–112 dBm/Hz

Measurement Bandwidth
1 MHz
1 MHz
1 MHz
1 MHz

12000

Frequency
in kHzAll PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint withfrequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at themeasurement frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at
frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask
continued the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It wasrecognized that this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.

NOTE 1 –NOTE 2 –NOTE 3 –NOTE 4 –NOTE 5 –NOTE 6 –Figure Q.14: Overlapped Downstream Channel PSD Mask.

Q.4.8.3

Spectral Shaping of the In-Band Region of the PSD Spectrum

In order to shape the ATU-C PSD, frequency dependent gains, called spectral shaping values (ssvi ), shall be applied oneach tone during initialization and showtime. The ssvi values shall be represented with 1 bit before and 10 bits after thedecimal point.
Table Q.2 defines the corner points for the nominal PSD shape of the inband region as gain in dB, i.e log_ssvi. Log_ssvi
on other tones shall be linearly interpolated between corner points on a logarithmic scale for the gain (dB) and a linear
scale for the frequency (Hz). Note that the corner points defined in Table Q.2 are relative values. Table Q.3 defines thesimilar corner points for the overlapped spectrum.
The spectral shaping values shall be converted from logarithmic scale (log_ssvi, dB values) to linear ssvi values
according to:log_ ssvi⎛⎞
Round ⎜⎜1024 × 10 20 ⎟⎟⎝⎠ssvi =
1024

These points are not passed at initialization for the nominal PSD shape but are provided here for reference. However,for additional spectral shaping (see Q.4.8.5), parameters are passed during G.994.1.
The combined accuracy of the process of linear interpolation of the log_ssvi values and the process of conversion tolinear ssvi values shall be strictly less than one half lsb of the 10 bit after the decimal point format of the linear ssvi
values. No error shall be introduced when log_ssvi equals 0dB or is interpolated between log_ssvi values, which equal
0dB.
NOTE 1:NOTE 2:

The above definition ensures that the maximum deviation between ssvi values used by transmitter andreceiver is one lsb.
The above needs an accuracy that is strictly < 1/2 lsb. An accuracy of = 1/2 lsb, will lead to inaccurate
results.

Table Q.2: Corner points for the non-overlapped nominal in-band PSD shape.
Tone Index
n1

Log_ssvi (dB)
0

256
376
869

0
–10
–13.5

Comments
f1 kHz defines the beginning of the inband region. No shaping is applied in the
low stop band.
1104 kHz
1622 kHz ( –10 = –50 – Nominal_PSD_lowband)
3750 kHz ( –13.5 = –53.5 - Nominal_PSD_lowband)- 152 -

Table Q.3: Corner points for the overlapped nominal in-band PSD shape
Tone Index
6

Log_ssvi (dB)
0

256
376
869

0
–10
–13.5

Comments
25.875 kHz defines the beginning of the inband region. No shaping is appliedin the low stop band.
1104 kHz
1622 kHz (–10 = –50 – Nominal_PSD_lowband)
3750 kHz (–13.5 = –53.5 – Nominal_PSD_lowband)

The absolute values of the transmit PSD are obtained by scaling the relative shaping values with a
NOMINAL_PSD_lowband, defined for the lower in-band frequencies. Note that the nominal in-band transmit PSD isfrequency dependent. The NOMINAL_PSD_lowband is –40 dBm/Hz (below 1104 kHz) for both the overlapped andnon-overlapped spectra.
NOTE 3: In-band PSD spectral shaping is applied prior to the IFFT.
NOTE 4: The value of MAXNOMATPds may be limited by regional regulations.
Q.4.8.4

Transmit Signals with Limited Transmit PowerFor cases where the transmit signal must be limited to a maximum aggregate transmit power (e.g. ATPdsmax = +20dBm), thenc)

During initialization the PSD transmit level is specified as an offset from the nominal value, i.e.
(Nominal_PSD_lowband + ssvi – x – power cutback) dB, and all values of gi = 1 for the offset value x and power
cutback. The value of x shall be the greater of 0 dB and (21.1 – ATPdsmax) dB for non-overlapped and (21.5 –ATPdsmax) dB for overlapped. For ATPdsmax = 20 dBm, the corresponding value of x shall be 1.1 dB for nonoverlapped and 1.5 dB for overlapped cases.

b)

If bi>0, then valid range for gi is [-14.5 to +2.5+x] (dB) ;If bi>0, then gi shall be in the [gsync – 2.5 to gsync + 2.5] (dB) range;
If bi=0, then gi shall be equal to 0 (linear) or in the [-14.5 to gsync] (dB) range;
For G.992.1 Annex Q-EU, gsync <= x dB

The gi values shall be constrainted by following relation:
Constraint on gi values

2* NSCds −1∑ ssvi ∗ g i ≤
2

2

i =32

Q.4.8.5

2* NSCds −1

∑ ssv

i =32

2
i

Additional inband spectral shaping

An ATU-R may request additional downstream inband spectral shaping by passing parameters to the ATU-C in a
G.994.1 MP, or MS message. The ATU-C may select additional downstream inband spectral shaping by passing
parameters to the ATU-R in a G.994.1 MS message. Within the framework of G.994.1, the ATU-C has the ability tomake the final decision on the downstream inband PSD shape to be used.
The additional inband spectral shaping parameters are listed in Q.7.2.2 and defined in Q.7.3. If the Additional inband
spectral shaping Spar(2) bit is set to ONE in Table Q.7.2, its associated Npar(3) octets in Tables Q.7.2.1 to Q.7.2.1.5
define the inband spectral shape. If the additional inband spectral shaping Spar(2) bit is set to ZERO, its associatedNpar(3) octets are not transmitted and the nominal inband PSD shape defined in Q.4.8.3 shall be used. These Npar(3)octets define the downstream PSD levels in the low band (between f1 and 1104 kHz), at 1622 kHz and at 3750 kHz.
The PSD levels between 1104 kHz and 1622 kHz, and between 1622 kHz and 3750 kHz are linearly interpolated in log
scale. The defined values are the PSD level in dB below the NOMINAL_PSD_lowband of –40dBm/Hz. For example, if
all three values are set to 20 dB, the result will be a flat PSD of –60dBm/Hz. If the three values are set to 2 dB, 12 dB
and 15.5 dB, the result is the PSD defined in Q.4.8.1 reduced by 2dB. In order not to violate the PSD mask defined in
Q.4.8.1, the second value shall be no less than 10 dB and the third value shall be no less than 13.5 dB.

- 153 -

Q.4.8.6

Egress control

G.992.1 Annex Q-EU equipment shall be able to reduce the PSD below –80 dBm/Hz for the Amateur radio bands
between 1.81 MHz and 2.00 MHz, and between 3.5 MHz and 3.8 MHz. The ATU-C may apply additional spectral
shaping as described in Q.4.8.5 to help achieve this requirement.

Q.4.9

Support of higher downstream bit rates with S = 1/2n (replaces 7.6.4)

With a rate of 4000 data frames per second and a maximum of 255 bytes (maximum RS codeword size) per data frame,
the ADSL downstream line rate is limited to approximately 8 Mbit/s per latency path. The line rate limit can beincreased beyond this for the interleaved path by mapping 2n RS codewords into one FEC data frame (i.e. by using S =1/2n in the interleaved path). S = 1/2n shall be used in the downstream direction only over bearer channel AS0.
For a selected value of n ≥ 1, the KI data bytes per interleaved mux data frame shall be packed into 2n RS codewords,
split into n equal parts, each consisting of 2 consecutive RS codewords. This forces rate adaptation to occur in 32n
kbit/s increments. Each of the n parts of the data frame shall begin with a sync byte and shall obey the rules defined inTable Q.4 for insertion of dummy bytes. The smallest value of n that can support the KI data bytes shall be used.
Support of S = 1/2 (i.e., n=1), S = 1/4 (i.e., n=2), S = 1/6 (i.e., n=3), and S = 1/8 (i.e., n=4), is mandatory.
The resulting data frame structure shall be as shown in Figure Q.15.
N1
Sync
Byte

PayloadN2 = N 1 or N 1-1

R

PayloadR

N2n-1 = N1
Sync
Byte

PayloadN2n = N2

R

PayloadR

NI
Figure Q.15 – Data frame for S = 1/2n mode
When KI is divisible by 2n, the 2n codewords have the same length N2i-1 = N2i = (KI/2n + RI) for i = 1 to n, otherwise
the odd numbered codewords are equal and are one byte longer than the even numbered codewords, i.e. N2i-1 =(KI + n)/2n + RI bytes, and N2i = (KI – n)/2n + RI bytes for i = 1 to n. For the FEC output data frame, NI =

∑ N,
n

i =1

i

with NI < 512n - 1 bytes.
The convolutional interleaver requires all codewords to have the same odd length. To achieve the odd codeword length,
insertion of dummy (not transmitted) bytes may be required. For S = 1/2n, the dummy byte addition to the odd
numbered and/or even numbered codewords at the input of the interleaver shall be as in Table Q.4.

Table Q.4/G.992.1 –Dummy byte insertion at interleaver input for S = 1/2n
N2i-1
Odd
Even
Odd
Even

N2i
Odd
Even
Even
Odd

Dummy Byte Insertion Action
No action
Add one dummy byte at the beginning of all codewords
Add one dummy byte at the beginning of each even numbered codeword
Add one dummy byte at the beginning of each odd numbered codeword and two dummy bytes
at the beginning of each even numbered codeword [the de-interleaver shall insert one dummy
byte into the de-interleaver matrix on the first byte and the (D + 1)th byte of the corresponding
codeword to make the addressing work properly]- 154 -

Q.5

ATU-R Functional Characteristics (pertains to clause 8)

Q.5.1

Framing (pertains to 8.4)

Q.5.1.1

Superframe structure (replaces 8.4.1.1)

The superframe structure of ATU-R transmitter is identical to that of ATU-C transmitter, as specified in Q.4.3.1.
Q.5.1.2

Hyperframe structure (replaces 8.4.1.3)

The hyperframe structure of ATU-R transmitter is functionally similar to that of ATU-C transmitter, except that theinverse synch symbol is used in the 1st superframe (SPF#0) (see Figure Q.16). The hyperframe is composed of 345
DMT symbols, numbered from 0 to 344. Each symbol is under FEXTC or NEXTC duration (see Q.5.3), and thefollowing numerical formula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-R
transmitter (see Figure Q.17).
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbol
then NEXTC symbol

128 DMT symbols are allocated in the FEXTC duration, and 217 DMT symbols are allocated in the NEXTC duration.
The symbols are composed of:
FEXTC symbol:
Number of symbol using Bitmap-FC
Number of synch symbol
Number of inverse synch symbol
NEXTC symbol:
Number of symbol using Bitmap-NC
Number of synch symbol

= 126
=1
=1
= 214
=3

During FEXT Bitmapping mode, the ATU-R shall not transmit any signal.

- 155 -

5 Superframe (= 340 frames)(point B)

1 Superframe = 68 frames (17 ms)

1 frame = 250 µs

Rate-Converter(point U-R, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#6

TC#33

TTRR
ATU-R
Crosstalk

NEXT

NEXT

FEXT
Hyperframe = 345 symbols (85 ms)

FEXT

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol N N N N N F F F F N N N

SPF#2

SPF#1
N F F I F N

S

S

SPF#3

SPF#4
S

S
T1532870-99

Sliding window

FEXTC duration

1 symbol = 246 µs
I

Inverse synch symbol

S

NEXTC Synch symbol

F

Symbol using Bitmap-FC (FEXTC duration bitmap)

N

Symbol using Bitmap-NC (NEXTC duration bitmap)

S

FEXTC Synch symbol

Figure Q.16/G.992.1 – Hyperframe structure for upstream- 156 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

ISS

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

101

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

SS

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

17

173

174

175

176

177

178

179

180

181

172
182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

SS

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

244

245

246

247

248

249

250

251

252

253

24

243

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

SS

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

SS

ISS Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol SS NEXTR synch symbol
NEXTR data symbol

T1535340-00

Figure Q.17/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Upstream

Q.5.1.3

Subframe structure (replaces 8.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table Q.5. The 34 subframes forma hyperframe.

- 157 -

Table Q.5/G.992.1 – Subframe (upstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

Q.5.2

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Inverse Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Synch Symbol#344 is Synch Symbol

Dual Bitmapping and rate conversion (replaces 8.15)

The function of the rate converter (see Q.5.2.2), tone ordering (see Q.5.4), constellation encoding, and gain scaling shalluse one of two bitmaps stored in the ATU. This method is called the dual bitmap.
Q.5.2.1

Dual Bitmap (new)The Dual Bitmap switching shall be the same as for the downstream data, specified in Q.4.4.1. The number of bits andthe relative gains to be used for every tone are calculated in the bit loading algorithm during the initialization sequence,and transmitted in C-B&G.
Q.5.2.2
Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FC, Bitmap-NC and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amounts of fast and interleaved data in Bitmap-FC and Bitmap-NC shall be calculated in thefollowing formulae:
If tCf ≤ nCmax:- 158 -

nCf = tCf
nCi = nC − nCf
f Cf = tCf
f Ci = f C − f Cf
If tCf > nCmax:

nCf = nC max

nCi = 0⎧⎡ tCf × 10 − nCf × 6 ⎤⎪ f Cf 4 = ⎢
⎥
4
⎢
⎪
⎥
f Cf = ⎨⎡ tCf ×10 − nCf × 7 ⎤⎪⎥⎪ f Cf 3 = ⎢3⎢⎥⎩⎧ f Ci 4 = f C − f C 4
f Ci = ⎨⎩ f Ci 3 = f C − f Cf 3
Where:
tCf
tCi
fCf and nCf
fCf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of fast bits in Bitmap-FC if the subframe (see Q.5.1.3) contains 3 Bitmap-FC except
for synch symbols.
fCf4
is the number of fast bits in Bitmap-FC if the subframe contains 4 Bitmap-FC except for synch
symbols.
fCi and nCi
are the numbers of interleaved bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of total bits in Bitmap-NC, which is specified in the B&G tables.
nC
During FEXT Bitmap mode, nCf and nCi are zero.

To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tCf ≤ nCmax:

dummyCf = 0

dummyCi = ( f Ci × 126 + nCi × 214) − tCi × 340
If tCf > nCmax:()
dummyCf 3 = ( f Cf × 3 + nCf × 7 ) − tCf ×10

dummyCf 4 = f Cf × 4 + nCf × 6 − tCf ×10

dummyCi = ( f Ci 4 × 96 + f Ci 3 × 30) − tCi × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FC constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:
dummySCf = fCf3 – fCf4

- 159 -

The receiver shall determine Bitmap-FC and Bitmap-NC so that dummyCi is less than 126, dummyCf4 is less than 4 anddummyCf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.
Q.5.3

FEXT Bitmapping (replaces 8.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (Q.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures Q.10 and Q.16).
Annex Q-EU does not support the FEXT Bitmapping mode.
Q.5.4

Tone Ordering (pertains to 8.7)

The tone ordering algorithm shall be the same as for the downstream data, specified in Q.4.4.
For Bitmap-FC, the "tone-ordered" encoding shall first assign fCf bits from the rate converter (see Q.5.2.2) to the tones
with the smallest number of bits assigned to them, and the remaining fCi bits to the remaining tones. For Bitmap-NC, it
shall first assign nCf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nCi bits to the remaining tones. Two ordered bit tables for Bitmap-FC and Bitmap-NC shall be prepared.
Q.5.5
Q.5.5.1

Modulation (pertains to 8.11)
Inverse synchronization symbol (replaces 8.11.4)

Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phase reversal of Synchronization
symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
Q.5.5.2

Gain scaling in synchronization symbol (new)At initialization time, the sync symbol reference transmit PSD level shall be set at the nominal PSD level+10log(gsync2) dBm/Hz, with gsync2 defined as the average gi2 value over the used (i.e. bi > 0) subcarriers in theNEXT or FEXT bitmap, whichever results in the highest average gain. The sync symbol reference transmit PSD shallnot be updated with used subcarrier gain changes during SHOWTIME.
I.5.5.3

Nyquist frequency (supplements 8.11.1.2)

The upstream Nyquist frequency for Annex Q-EU shall be at subcarrier NSCus (f = 4.3125*NSCus kHz).
I.5.5.4

Modulation by the inverse discrete Fourier transform (supplements 8.11.2)

For Annex Q-EU, see A.2.1.
I.5.5.5

Synchronization symbol (supplements 8.11.3)

For Annex Q-EU, see A.2.2.

Q.5.6

ATU-R Upstream Transmit Spectral Mask (replaces 8.14)

The upstream PSD masks of Annex Q-EU are defined with absolute peak values in Figure Q.18. The low frequency
stop band is defined for frequencies below 25.875 kHz; the high frequency stop band is defined at frequencies greaterthan f1 kHz (tone n1). The in-band region of these PSD masks is the frequency band from 25.875 kHz to f1 kHz.
ATU-x may optionally support upstream masks EU-36 to EU-64 specified in Figure Q.18
NOTE: The value of MAXNOMATPus may be limited by regional regulations.

- 160 -

PSD indBm/HzPEAKPSD(PEAKPSD+92.5)/2.69
dB/octave–72 dB/octave–100 dBm/Hz peak
–15 dB/octave–97.5
15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 1411 kHz–92.5 peak
PSD_int dBm/Hz–110 dBm/Hz–112 dBm/Hz

0425.875

f1

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < f1
f1< f < f_int
f_int < f < 686
f > 686
Frequency (kHz)04
425.875f1
f_int
686 – 12000

f_int

686

1411
1630 5275

Equation for line (dBm/Hz)-97.5-92.5+(PEAKPSD+92.5)* log2(f/4)/log2(25.875/4)
PEAKPSDPEAKPSD-72*log2(f/f1)
PSD_int-15*log2(f/f_int)-100
PSD level (dBm/Hz)
-97.5
-97.5
-92.5
PEAKPSDPEAKPSD
PSD_int-100

Measurement BW
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz

Additionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
1411
1630
5275
12000

Frequency
12000 in kHz

PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

NSCus is a function of the upstream mask parameters, which are defined as follows:- 161 -

Parameters in FEXT bitmap for mode 1, both bitmaps for mode 2 (see §Q.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

32
64
64
64
64
64
64
64
64

Template
Nominal PSD
P0 (dBm/Hz)

-38.0
-38.5
-39.0
-39.4
-39.8
-40.1
-40.4
-40.7
-41.0

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.0
-35.5
-35.9
-36.3
-36.6
-36.9
-37.2
-37.5

138.00155.25172.50189.75207.00224.25241.50258.75276.00242.92274.03305.06336.33367.54399.07430.58462.04493.45

-93.2
-94.0
-94.7
-95.4
-95.9
-96.5
-97.0
-97.4
-97.9

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.2
-36.4
-37.2
-37.9
-38.3
-38.6
-38.8
-38.8

138.00155.25172.50189.75207.00224.25241.50258.75276.00242.92273.47302.26331.87361.55392.16423.12454.51486.91

-93.2
-94.0
-94.7
-95.3
-95.8
-96.4
-96.9
-97.3
-97.8

Parameters in NEXT bitmap for mode 1 (see §Q.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

Template
NominalPSD P0(dBm/Hz)

32
64
64
64
64
64
64
64
64

-38.0
-38.7
-39.9
-40.7
-41.4
-41.8
-42.1
-42.3
-42.3

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

NOTE 1 – All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
NOTE 2 – The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The breakpoints
in the tables shall be connected by linear straight lines on a dB/log(f) plot.
NOTE 3 – MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint with frequency fi
is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next specified breakpoint.
NOTE 4 – The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
NOTE 5 – The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued the21.5 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that this might impact
V.90 performance, and so the floor was extended to 4 kHz.
NOTE 6 – All PSD and power measurements shall be made at the U-R interface (see Figures Q.3 & Q.4).
Figure Q.18: Upstream Channel PSD Masks
When EU-S68 or beyond is used, only mode 2 shall be used. The PSD masks are defined in Figure Q.x1 and Table
Q.x2. The frequency band from 25.875 kHz to f_upper can be used.

- 162 -

Frequency band f (kHz)
Equation for line (dBm/Hz)
0<f<4
-97.5
4 < f < 25.875-92.5+(PEAKPSD+92.5)* log2(f/4)/log2(25.875/4)
25.875 < f < f1
PEAKPSDf1< f < f_upper
PEAKPSD-24*log2(f/f1)
f_upper < f < 686
PSD_upper-((PSD_upper+100)/log2(686/f_upper))*log2(f/f_upper)f > 686-100
Note: PSD_upper=PEAKPSD-24*log2(f_upper/f1)

Frequency (kHz)04
4
1025.875276
f_upper
686
5275
12000

PSD level (dBm/Hz)
-97.5
-97.5
-92.5
interpolated
-38.6
-38.6
PSD_upper
-100
-100
-100

Measurement BW
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHzFigure Q.x1: Mask definition for EU-S68 to EU-S96

Designator
EU-S68
EU-S72EU-S76
EU-S80EU-S84
EU-S88
EU-S92EU-S96

Template
Maximum
Aggregate
Transmit Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

Upper
Frequency
f_upper(kHz)

PSD_upper:
PSD Level at
f_upper(dBm/Hz)293.25
310.50327.75345.00362.25379.50396.75414.00-40.70-42.68-44.55-46.33-48.02-49.63-51.17-52.64

Table Q.x2: Parameters for EU-S68 to EU-S96- 163 -

Q.5.7

Forward error correction (supplements 8.6)

The minimum FEC coding capabilities (Table 8-3) for an ATU-R shall include the following interleave depths for theinterleaved buffer:
D = 1, 2, 4, 8, and 16
Q.5.8

Cyclic prefix (supplements 8.12)

For Annex Q-EU, see A.2.3.

Q.6

EOC Operation and Maintenance (pertains to clause 9)

Q.6.1

ADSL line related primitives (supplements 9.3.1)

Q.6.1.1

ADSL line related near-end defects (supplements 9.3.1.3)

Two near-end defects are further defined:••

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.
Severely errored frame (SEF): A SEF defect occurs when the content of two consecutively received ADSL
synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R, does notcorrelate with the expected content over a subset of the tones. An SEF defect terminates when the content of twoconsecutively received ADSL synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR
duration at ATU-R, correlate with the expected contents over the same subset. The correlation method, theselected subset of tones, and the threshold for declaring these defect conditions are implementation discretionary.

Q.6.1.2

ADSL line related far-end defects (supplements 9.3.1.4)

Loss-of-signal is further defined:•

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.

Q.6.2

Test Parameters (supplements 9.5)

Q.6.2.1

Near-end test parameters (supplements 9.5.1)

The near-end primitives are further defined:••

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio (SNR) margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.

Q.6.2.2

Far-end test parameters (supplements 9.5.2)

The far-end primitives are further defined:••

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio SNR margin: During FEXT Bitmap mode, this primitive represents the snr margin in the- 164 -FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.
Q.6.3

Data registers in the ATU-R (supplements 9.2.4)

For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7

Initialization (pertains to clause 10)

Q.7.1

Initialization with Hyperframe (replaces 10.1.5)

The exchange of messages between ATU-C and ATU-R should be performed in FEXTC and FEXTR. The DMT
symbol has two symbol rates: one is 4.3125 kbaud for the symbol without a cyclic prefix, and the other is 4 x 69/68
kbaud for the symbol with a cyclic prefix. 32 times of the TTR has the same period as 345 times of the 4.3125 kbaud,
and 34 times of the TTR is the same as 345 times of 4 x 69/68 kHz.
During FEXT Bitmap mode, the ATU-R shall not transmit any signal during the NEXTC symbols duration and the
ATU-C shall transmit only the pilot tone as the NEXTR signal except:• C-PILOT1 (C-PILOT1A) which is accompanied by a signal to allow the ATU-C to indicate the phase of TTRC
to the ATU-R (see Q.7.4.1);• C-QUIETn where no signal is transmitted.
The ATU-C begins transmitting C-PILOT1 at the beginning of the hyperframe without cyclic prefix. The ATU-C
informs the phase of the TTRC to ATU-R during C-PILOT1. The ATU-R begins transmitting R-REVERB1 at the
beginning of the hyperframe without cyclic prefix. The ATU-R performs the training of any receiver equalizer using
this phase information of the TTRR generated from received TTRC.
From C-PILOT1 to C-SEGUE1, the following numerical formula gives the information which duration Ndmt-th DMT
symbol belongs to at ATU-R (see Figure Q.19).
For Ndmt = 0, 1, …344
S = 256 x Ndmt mod 2760
if { (S + 255 < a) or (S > a + b) }else
where a = 1243, b = 1461

then FEXTR symbols
then NEXTR symbols

In order to enter C-RATES1 at the beginning of the hyperframe with cyclic prefix, the number of symbols from
C-PILOT1 to C-SEGUE1 shall be a multiple of 345 DMT symbols.
From R-REVERB1 to R-SEGUE1, the following numerical formula gives the information which duration Ndmt-th
symbol belongs to at ATU-C (see Figure Q.20).
For Ndmt = 0, 1, …, 344,
S = 256 x Ndmt mod 2760
if { (S > a) and (S + 255 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols

From C-RATES1 to C-SEGUE3, the number of symbols is a multiple of 345 DMT symbols. The following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-C transmits the message data in
FEXTR symbols (see Figure Q.11).

- 165 -

For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760
if { (S + 271 ≥ a) and (S ≤ a + b) }else
where a = 1243, b = 1461

then NEXTR symbols
then FEXTR symbols

The ATU-R enters R-REVERB3 at the beginning of the hyperframe with cyclic prefix, which is extracted fromreceived signal. From R-REVERB3 to R-SEGUE5, the number of symbols is a multiple of 345 DMT symbols. The
following numerical formula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-R transmits
the message data in FEXTC symbols (see Figure Q.17).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols- 166 -

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14

0

1

2

3

4

5

6

7

8

9

10

11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
107
97
98
99
100
101
102
103
104
105
106
108
109
110
111
112
113
114
115
116
117 118
119
120
121
122
123
124
125
126
127
128
129 130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
161
151
152
153
154
155
156
157
158
159
160

162
163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181
182
184
185
186
187
188
189
190
191
192
193
17 183
204
195
196
197
198
199
200
201
202
203
18 194
205
206
207
208
209
210
211
212
213
214 215
19
20
216
217
218
219
220
221
222
223
224
225
228
229
230
231
232
233
234
235
236
21 226 227
238
239
240
241
242
243
244
245
246
247
22 237
258
248
249
250
251
252
253
254
255
256
257
23
24
259
260
261
262
263
264
265
266
267
268 269
15
16

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311 312
313
314
315
316
317
318
319
320
321
322
29
323
324
325
326
327
328
329
330
331
332
333
30
335
336
337
338
339
340
341
342
343
344
31 334
25
26
27
28

280

FEXTR symbol

T1535350-00

NEXTR symbol

Figure Q.19/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Downstream- 167 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

10

1

11

12

13

14

15

16

17

18

19

20

2

22

23

24

25

26

27

28

29

30

31

3 32
4 43
5

33

34

44

54

35

45

55

6

65

7 75
8 86

76

56

66

57

77
98

99

108

109

110

23
24

82

92

102

112

62

72

63

73

83

93

103

113

64

74

84

94

104

114

53

85

95

105

115

96
107

106

116

117

118

121

122

123

124

125

126

127

128

132

133

134

135

136

137

138

139

142

143

153

163

144

154

164

145

155

165

146

156

166

147

157

167

148

158

168

149

159

169

150
161

160

170

171

172

174

175

176

177

178

179

180

181

182

184

185

186

187

188

189

190

191

192

193
204

195

205

196

206

216

21 22622 239

81

91

101

111

61

71

42

52

173

17 18318 194
19
20

80

41

51

131
152

162

15
16

60

70

90

40

50

120

141

140
151

59

79
100

39

49

69

89

97

14

58

78

9

38

48

68

88

10

13

37

47

67

87

119
11
12 129 130

36

46

21

197

207

217

198

208

218

199

209

219

200

210

220

201

211

221

202

212

222

203

213

223

215

214

224

225

227

228

229

230

231

232

233

234

235

236

238

239

240

241

242

243

244

245

246

247
258

248

249

259

250

260

251

261

252

262

253

263

254

264

255

265

256

266

257

267

268

269

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
26 280
292
293
294
295
296
297
298
299
300
301
27 291
28
302
303
304
305
306
307
308
309
310
311
312
25

29
30 32331 334

313

314

324
335

315

325
336

316

326
337

317

327

318

328

338

339

319

329
340

320

330
341

321

331
342

322

332
343

333
344
T1535360-00

FEXTC symbol
NEXTC symbol

Figure Q.20/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Upstream

Q.7.2

Handshake – Non-standard information block (new)This section defines the format of the G.994.1 non-standard information block to support Annex Q-EU, and tabulates
the parameters used by Annex Q-EU. The use of these parameters is described in §Q.7.3 and §Q.7.4.

Q.7.2.1 Non-standard information block format (new)Figure Q.21 defines the format of the non-standard information block.

- 168 -

8

7

6

5

4

3

2

1

Non-standard information length = M + 6(1 octet)
T.35 country code
(2 octets – see Note 1)
Provider code (vendor identification)(4 octets – see Note 2)
Vendor-specific information(M octets – Note 3)
NOTE 1 – The value of this field shall be B5 00, the country code for USA
NOTE 2 – The value of this field shall be 43 45 4E 54, ASCII “CENT” for Centillium
Communications
NOTE 3 – These octets are defined in §Q.7.2.2. Formatting of these octets shall comply with theparsing rules defined in G.994.1 §9.2.1 to §9.2.3

Figure Q.21 – Non-standard information block format

Q.7.2.2 Non-standard information block parameters (new)The G.994.1 non-standard parameters for Annex Q-EU are listed in Tables Q.6 to Q.7.2.1.2.5 below.
In order to minimize message length, the parameters for additional inband spectral shaping (Spar(2) octet and its related
Npar(3) octets) shall only be included in MP or MS messages, and shall not be included in CLR or CL messages. All
Annex Q-EU modems shall support additional inband spectral shaping.
Note - This deviates from the rules specified in G.994.1 for standard information fields, where it isstated in §9.6:“Once a Transaction C (see 10.1) has been completed, any subsequent MS message
within the same G.994.1 session shall only contain those octets of the identification (I)and standard information (S) fields, and those blocks of non-standard information (NS)that were contained in both the CLR and CL messages of the previous Transaction C”.

Table Q.6 – Non-standard information field – NPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Reserved for future use

x

x

x

x

x

x

1

x

Reserved for future use

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet- 169 -

NPar(1)sTable Q.7 – Non-standard information field – SPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

G.992.1 Annex Q (and Annex Q-EU)

x

x

x

x

x

x

1

x

G.992.1 Annex I-EU

x

x

x

x

x

1

x

x

G.992.1 Annex C-EU

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet

SPar(1)sTable Q.7.1 – Non-standard information field – G.992.1 Annex Q NPar(2) coding – Octet 1
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

nC-PILOT1 = 64

x

x

x

x

x

x

1

x

nC-PILOT1 = 128

x

x

x

x

x

1

x

x

nC-PILOT1 = 256

x

x

x

x

1

x

x

x

Amateur radio notch – 1.8 MHz band

x

x

x

1

x

x

x

x

Amateur radio notch – 3.5 MHz band

G.992.1 Annex Q NPar(2)s – Octet 1

x

x

1

x

x

x

x

x

nC-PILOT1 = 96

x

x

0

0

0

0

0

0

No parameters in this octet

Since A48 is the only TTR indication signal specified for Annex Q-EU, there is no need to include it in G.994.1.

Table Q.7.1.1 – Non-standard information field – G.992.1 Annex Q NPar(2) coding – Octet 2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

R-ACK1

x

x

x

x

x

x

1

x

R-ACK2

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

G.997.1 – Clear EOC OAM

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex Q NPar(2)s – Octet 2

Since Annex Q-EU only supports ATM transport, STM and ATM parameters are not specified. Since FBM mode is
not supported, the DBM bit is also not specified.

- 170 -

Table Q.7.2 – Non-standard information field – G.992.1 Annex Q SPar(2) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Additional inband spectral shaping

x

x

x

x

x

x

1

x

Extended upstream

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex Q SPar(2)s

Table Q.7.2.1 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 1
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 1x

x

NOMINAL_PSD_lowband (bits 8 & 7)x

Reserved for future use

Table Q.7.2.1.1 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 2
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 2

x

x

x

x

x

x

x

x

NOMINAL_PSD_lowband (bits 6 to 1)

Table Q.7.2.1.2 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 3
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 3x

x

PSD level at 1622 kHz (bits 8 & 7)x

Reserved for future use- 171 -

Table Q.7.2.1.3 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 4
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 4

x

x

x

x

x

x

x

x

PSD level at 1622 kHz (bits 6 to 1)

Table Q.7.2.1.4 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 5
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 5x

x

PSD level at 3750 kHz (bits 8 & 7)x

Reserved for future use

Table Q.7.2.1.5 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 6
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 6

x

x

x

x

x

x

x

x

PSD level at 3750 kHz (bits 6 to 1)

Table Q.7.2.2 – Non-standard information field – G.992.1 Annex Q Extended upstream
NPar(3) coding Octet 1
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Extended upstream NPar(3)s Octet
1

x

x

x

x

x

x

x

1

Mode 1 upstream mask

x

x

x

x

x

x

1

x

Mode 2 upstream mask

x

x

x

x

x

1

x

x

Optional upstream masks for non-overlapped spectrum

x

x

x

x

1

x

x

x

EU-64

x

x

x

1

x

x

x

x

EU-32

x

x

1

x

x

x

x

x

EU-36

x

x

0

0

0

0

0

0

No parameters in this octet- 172 -

Table Q.7.2.2.1 – Non-standard information field – G.992.1 Annex Q Extended upstream
NPar(3) coding Octet 2
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Extended upstream NPar(3)s Octet
2

x

x

x

x

X

x

x

1

EU-40

x

x

x

x

X

x

1

x

EU-44

x

x

x

x

X

1

x

x

EU-48

x

x

x

x

1

x

x

x

EU-52

x

x

x

1

x

x

x

x

EU-56

x

x

1

x

x

x

x

x

EU-60

x

x

0

0

0

0

0

0

No parameters in this octet

Table Q.7.2.2.2 – Non-standard information field – G.992.1 Annex Q Extended upstream
NPar(3) coding Octet 3
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Extended upstream NPar(3)s Octet
3

x

x

x

x

X

x

x

1

EU-S68

x

x

x

x

X

x

1

x

EU-S72

x

x

x

x

X

1

x

x

EU-S76

x

x

x

x

1

x

x

x

EU-S80

x

x

x

1

x

x

x

x

EU-S84

x

x

1

x

x

x

x

x

EU-S88

x

x

0

0

0

0

0

0

No parameters in this octet

Table Q.7.2.2.3 – Non-standard information field – G.992.1 Annex Q Extended upstream
NPar(3) coding Octet 4
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Extended upstream NPar(3)s Octet
4

x

x

x

x

X

x

x

1

EU-S92

x

x

x

x

X

x

1

x

EU-S96

x

x

x

x

X

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet- 173 -

Q.7.3

Handshake – Parameter definitions (supplements 10.2)

Q.7.3.1 Handshake – ATU-C (supplements 10.2)
Q.7.3.1.1

CL messages (supplements 10.2.1)

See Table Q.8.

Table Q.8/G.992.1 – ATU-C CL message NPar(2) bit definitions for Annex Q
NSF parameter

Definition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-C is configured to support G.992.1
Annex Q, and possibly Annex Q-EU.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 96.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 256.
If set to ONE, this Npar(2) bit indicates that the ATU-C is configured to reduce its transmit
power between 1.81 and 2.0 MHz to ≤ –80 dBm.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band

Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped
spectrumIf set to ONE, this Npar(2) bit indicates that the ATU-C is configured to reduce its transmit
power between 3.5 and 3.8 MHz to ≤ –80 dBm.

If set to ONE, this Spar(2) bit indicates that the ATU-C is configured to support extended
upstream.
If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-C supports. For non-overlapped spectrum, extended upstream
masks are associated with downstream masks according to Figure Q.13. For overlapped
spectrum, any EU-xx may be used with the overlapped downstream spectrum specified in§Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support the optional
upstream masks when using non-overlapped spectrum downstream.

- 174 -

Q.7.3.1.2

MS messages (supplements 10.2.2)

See Table Q.9.

Table Q.9/G.992.1 – ATU-C MS message NPar(2) bit definitions for Annex Q
NSF bitG.992.1 Annex Q
nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_
lowband
PSD level at 1622
kHz

PSD level at 3750
kHz

Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped
spectrum

Definition

If set to ONE, this Spar(1) bit indicates that the ATU-C is selecting G.992.1 Annex Q, andpossibly Annex Q-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 256 (Note 1).
If set to ONE, this Npar(2) bit indicates that the ATU-C shall reduce its transmit power
between 1.81 and 2.0 MHz to ≤ –80 dBm.
If set to ONE, this Npar(2) bit indicates that the ATU-C shall reduce its transmit power
between 3.5 and 3.8 MHz to ≤ –80 dBm.
If set to ONE, this Spar(2) bit indicates that the ATU-C shall apply additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply in the passband below 1104 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply at 1622 kHz. It is coded in steps of 0.125dB relative to NOMINAL_PSD_lowband(–40dBm/Hz). For example, 00000000 means –40 dBm/Hz; 00001101 means -41.625
dBm/Hz. The PSD level shall be linearly interpolated in dBs between the
REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply at 3750 kHz. It is coded in steps of 0.125dB relative to NOMINAL_PSD_lowband(–40dBm/Hz). For example, 00000000 means –40 dBm/Hz; 00001101 means -41.625
dBm/Hz. The PSD level shall be linearly interpolated in dBs between the PSD level at 1622
kHz and the PSD level at 3750 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-C is selecting extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-C is selecting upstream PSD mask USxx. For non-overlapped spectrum, extended upstream masks are associated with downstream
masks according to Figure Q.13. For overlapped spectrum, any EU-xx may be used with theoverlapped downstream spectrum specified in §Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 1(different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 2(same mask during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

- 175 -

Note 1: One and only one pilot tone bit shall be set in an MS message.
Note 2: One and only one upstream mask mode bit shall be set in an MS message.

Q.7.3.2 Handshake – ATU-R (supplements 10.3)
Q.7.3.2.1

CLR messages (supplements 10.3.1)

See Table Q.10.

Table Q.10/G.992.1 – ATU-R CLR message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-R is configured to support G.992.1
Annex Q, and possibly Annex Q-EU.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 96.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 256.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports the 1.8 MHz
Amateur radio band notch.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports the 3.5 MHz
Amateur radio band notch.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Amateur radio notch– 3.5 MHz band

Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum

If set to ONE, this Spar(2) bit indicates that the ATU-R is configured to support extended
upstream.
If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-R supports. For non-overlapped spectrum, extended upstream
masks are associated with downstream masks according to Figure Q.13. For overlapped
spectrum, any EU-xx may be used with the overlapped downstream spectrum specified in§Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support the optional
upstream masks when using non-overlapped spectrum downstream.

- 176 -

Q.7.3.2.2

MS messages (supplements 10.3.2)

Table Q.11.

Table Q.11/G.992.1 – ATU-R MS message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-R is selecting G.992.1 Annex Q, andpossibly Annex Q-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_
lowband
PSD level at 1622
kHz

PSD level at 3750
kHz

Extended
upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped
spectrum

This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 3750 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 3750 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-R is selecting upstream PSD mask USxx. For non-overlapped spectrum, extended upstream masks are associated with downstream
masks according to Figure Q.13. For overlapped spectrum, any EU-xx may be used with theoverlapped downstream spectrum specified in §Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode 1(different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode 2(same mask during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

- 177 -

Note 1: One and only one pilot tone bit shall be set in an MS message.
Note 2: One and only one upstream mask mode bit shall be set in an MS message.

Q.7.3.2.3

MP messages (new)Table Q.12.
Table Q.12/G.992.1 – ATU-R MP message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-R is proposing G.992.1 Annex Q, andpossibly Annex Q-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is proposing the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_lowbandPSD level at 1622
kHz

PSD level at 3750
kHz

Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped
spectrum

This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs between
the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 3750 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs between
the PSD level at 1622 kHz and the PSD level at 3750 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-R is proposing upstream PSD mask USxx. For non-overlapped spectrum, extended upstream masks are associated with downstream
masks according to Figure Q.13. For overlapped spectrum, any EU-xx may be used with theoverlapped downstream spectrum specified in §Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode 1(different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode 2(same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing one of the optional
upstream masks when using non-overlapped spectrum downstream.

- 178 -

Note 1: More than one pilot tone bit may be set in an MP message.

Q.7.4

Transceiver Training – ATU-C (supplements 10.4)

During transceiver training from C-REVERB1 to C-SEGUE1 except C-PILOTn and C-QUIETn, the ATU-C shalltransmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), and shall not transmit
the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state isdefined as Figure Q.26.
Q.7.4.1

C-PILOT1 (supplements 10.4.2)

The ATU-C shall start the NSWF (sliding window frame) counter from 0 immediately after entering C-PILOT1, andincrement the NSWF counter modulo 345 after transmission of each DMT symbol. According to the sliding windowfunction and this counter, the ATU-C decides to transmit all of the subsequent symbols in either FEXTR or NEXTR
symbols (for example, see Figures Q.11, Q.19 and Q.24).
C-PILOT1 has two signals.
The first signal is the pilot tone, a single frequency sinusoid at fC-PILOT1 defined as:⎧ 0, k ≠ nC − PILOT 1 , 0 ≤ k ≤ NSCds
Xk = ⎨
AC − PILOT 1 , k = nC − PILOT 1⎩
The frequency of the pilot tone shall be selected from one of the following choices during G.994.1 as:
8. fC-PILOT1 = 276 kHz (nC-PILOT1 = 64).
9. fC-PILOT1 = 414 kHz (nC-PILOT1 = 96).
10. fC-PILOT1 = 552 kHz (nC-PILOT1 = 128).
11. fC-PILOT1 = 1104 kHz (nC-PILOT1 = 256).
Transmitters that support Annex Q-EU shall support all of these pilot tones.
The second signal is the TTR indication signal used to transmit NEXTR/FEXTR information. The ATU-R can detect
the phase information of the TTRC from this signal. The TTR indication signal shall be selected during G.994.1 as:
A48 signal –the constellation encoding of the 48th carrier with 2-bit constellation as follows:(+ , +) to indicate a FEXTR symbol;(+ , –) to indicate a NEXTR symbol.
Q.7.4.2

C-PILOT1A (supplements 10.4.3)

C-PILOT1A has two signals and it is the same transmitted signal as C-PILOT1 (C.7.4.1).
Q.7.4.3

C-REVERB3 (supplements 10.4.11)

In order to synchronize the first symbol of C-RATES1 with the beginning of the hyperframe and to inform the enteringtiming of C-RATES1 to the ATU-R, the first symbol of C-SEGUE1 shall be transmitted inside of the FEXTR duration
as shown in Figure Q.22. Therefore, the duration of C-REVERB3 is 3628 DMT symbols.

- 179 -

TTRC
20 symbols
C-SEGUE1

C-REVERB3

C-RATES1

the time of the detection
C-SEGUE1

R-REVERB3
T1532880-99

Figure Q.22/G.992.1 – Timing diagram from C-SEGUE1 to C-RATES1

Q.7.4.4 C-REVERB1 (replaces 10.4.5)
C-REVERB1 is a signal that allows the ATU-C and ATU-R receiver to adjust its automatic gain control (AGC) to an
appropriate level. The data pattern used in C-REVERB1 shall be the pseudo-random downstream sequence (PRD), dn
for n = 1 to 2*NSCds, defined in Q.4.7.5 and repeated here for convenience:dn = 1dn = dn-4 ⊕ dn-9

for n = 1 to 9
for n = 10 to 2*NSCds(10-1)The bits shall be used as follows: the first pair of bits (d1 and d2) is used for the DC and Nyquist subcarriers (the powerassigned to them is, of course, zero, so the bits are effectively ignored); then the first and second bits of subsequentpairs are used to define the Xi and Yi for i = 1 to NSCds-1 as defined in Table 7-13.
The period of PRD is only 511 bits, so dn+511 is equal to dn. The bits d1 to d9 shall be re-initialized for each symbol,
so each symbol of C-REVERB1 is identical.
The two bits that modulate the pilot carrier shall be overwritten by {0,0}: generating the {+,+} constellation.
The duration of C-REVERB1 is 512 (repeating) symbols without cyclic prefix.
Q.7.4.4.1

Power Cut-back (supplements 10.4.5.1)

For Annex Q-EU, see A.3.1.

Q.7.5

Transceiver Training – ATU-R (supplements 10.5)

During transceiver training from R-REVERB1 to R-SEGUE1 except R-QUIETn, the ATU-R shall transmit both
FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC
symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is defined as Figure Q.26.
Q.7.5.1

R-QUIET2 (supplements 10.5.1)

The ATU-R enters R-REVERB1 after it completes timing recovery and Hyperframe synchronization from
C-PILOT1/C-PILOT1A.
Q.7.5.2

R-REVERB1 (supplements 10.5.2)

The data pattern used in R-REVERB1 is the pseudo-random upstream sequence PRU defined in 8.11.3, repeated as- 180 -

necessary for the the selected NSCus:⎧d n = 1⎨⎩d n = d n − 5

for n = 1 to 6
⊕ d n −6 for n = 7 to 2 * NSCus(C.10-1)

The period of PRU is only 63 bits, so dn+63 is equal to dn.
The ATU-R shall start its NSWF counter immediately after entering R-REVERB1, and then increment the NSWF
counter with modulo 345 from 0 when it transmits each DMT symbol. The ATU-C and ATU-R shall have the samevalue since hyperframe alignment between the ATU-C and ATU-R shall be maintained. According to the sliding
window and this counter, the ATU-R decides to transmit all of the subsequent symbols in either the FEXTC or the
NEXTC symbol.
Q.7.5.3

R-QUIET3 (replaces 10.5.3)

The final symbol of R-QUIET3 accommodates the frame alignment of the transmitter to that of the receiver. It may be
shortened by any number of samples. The maximum duration of R-QUIET3 is 6145 DMT symbols.
Q.7.5.4

R-REVERB2 (supplements 10.5.5)

After ATU-R detects C-SEGUE1, the ATU-R enters R-SEGUE1. The maximum duration of R-REVERB2 is 3643
DMT symbols.
Q.7.6

Channel analysis (ATU-C) (supplements 10.6)

ATU-C shall transmit only FEXTR symbols, and shall not transmit the NEXTR symbols except the pilot tone from
C-RATES1 to C-CRC2. During C-MEDLEY, the ATU-C shall transmit both FEXTR and NEXTR symbols when
Bitmap-NR is enabled (Dual Bitmap mode). The ATU-C shall not transmit NEXTR symbols except the pilot tone,
when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state is defined in Figure Q.26.
Q.7.6.1

C-SEGUE1 (supplements 10.6.1)

The duration of C-SEGUE1 is 20 symbols in order that the first symbol of C-SEGUE1 shall be inside of the FEXTR
duration.
Q.7.6.2

C-MEDLEY (replaces 10.6.6)

C-MEDLEY is a wideband pseudo-random signal used for estimation at the ATU-R of the downstream SNR. The data
to be transmitted are derived from the pseudo-random sequence, PRDm defined as:
d n = 1 for n = 1 to 14 and d n = d n-5 ⊕ d n-11 ⊕ d n-12 ⊕ d n-14 for n> 14,
and modulated as defined in 10.4.5. In contrast to C-REVERB1, the cyclic prefix is used and the data sequence
continues from one symbol to the next (i.e. d1 to d14 are not re-initialized for each symbol). Because the sequence is oflength 214-1, and far fewer bits are used for each symbol, the subcarrier vector for C-MEDLEY changes from one
symbol period to the next. For non-overlapped spectrum, 2*(869-mm+1) bits are used each symbol, where mm is theminimum subcarrier specified for PSD mask DS-mm in Table Q.13. For overlapped spectrum, 2*864 bits are used eachsymbol. The pilot subcarrier is overwritten by the (+,+) signal constellation. The duration of C-MEDLEY is as shown in
Figure Q.26. Following C-MEDLEY the ATU-C shall enter the state C-REVERB4.
With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure Q.23. The ATU-C
transmits the signal in both of NEXTR and FEXTR symbols, and the ATU-R estimates two SNRs from the received
NEXTR and FEXTR symbols, respectively, as defined in Figure Q.24.
The following formula gives the information that received Ndmt-th DMT symbol belongs to:- 181 -

For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > d) }if { (S > b) and (S + 271 < c) }where a = 1243, b = 1403, c = 2613, d = 2704

then symbol for estimation of FEXTR SNR
then symbol for estimation of NEXTR SNR

When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbol. The
number of bits of NEXTR shall be no more than the number of bits of FEXTR.
At the transmitter, the PRDm sequence generator shall continue to be updated during NEXTR symbols when BitmapNR is disabled (FEXT Bitmap mode).

TTR
TCM-ISDN crosstalkat ATU-R receiver

TCM-ISDN crosstalkat ATU-C receiver

NEXT

NEXT

FEXT

FEXT

FEXT

NEXT

NEXT

NEXT

FEXT

FEXT
Estimation of
Signal-to-Noise ratio

C/R-MEDLEY (49152 symbols)

Bitmap for Downstream

Bitmap-NR

Bitmap-FR

Bitmap-FR

Bitmap-NR

Bitmap for Upstream

Bitmap-FC

Bitmap-NC

Bitmap-NC

Bitmap-FC
T1532890-99

Figure Q.23/G.992.1 – Estimation of periodic Signal-to-Noise Ratio- 182 -

TTRC
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

4
5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

101

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

137

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

17
18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

206

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

243

24

244

245

246

247

248

249

250

251

252

253

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

275

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

315

316

317

318

319

320

321

322

323

324

31

314

32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

Symbol for estimation of FEXTR S/N
Symbol for estimation of NEXTR S/N

Symbol not used for S/N estimation
T1535370-00

Figure Q.24/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Downstream

Q.7.6.3

C-RATES1 (supplements 10.6.2)

In order to support data rates greater than 32 Mbit/s, the BI field has 11 bits. The RRSI fields shall use the same
extended syntax as defined in Q.7.9.4 for C-RATES-RA.

- 183 -

For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7.6.4

C-MSG1 (supplements 10.6.4)

Table Q.13/G.992.1 – Assignment of 48 bits of C-MSG1
Suffix(ces) of mi (Note 1)
Parameter (Note 3)
47-44
Minimum required downstream SNR margin at initialization (Note 2)
43-18
Reserved for future use
17
Trellis coding option
16
Overlapped spectrum option (Note 4)
15
Unused (shall be set to "1")
14-12
Reserved for future use
11
NTR
10-9
Framing mode
8-6
Transmit PSD during initialization
5
Reserved
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – A positive number of dB; binary coded 0-15 dB.
NOTE 3 – All reserved bits shall be set to "0".
NOTE 4 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
Q.7.6.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.6.4.8)

The Ndownmax (transmit) capability shall be binary encoded onto {m4, ..., m0} (e.g. 100012 = 17). The maximum
number of bits for the upstream data, Nupmax, that the ATU-C receiver can support need not be signalled to the ATU-R;
it will be implicit in the bits and gains message, C-B&G, which is transmitted after channel analysis.
Q.7.7

Channel analysis (ATU-R) (supplements 10.7)

From R-RATES1 to R-CRC2, the ATU-R shall transmit only the FEXTC symbols and shall not transmit the NEXTC
symbols. In R-SEGUE2 and R-MEDLEY, the ATU-R shall transmit both FEXTC and NEXTC symbols when
Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC symbols when Bitmap-NC is disabled(FEXT Bitmap mode). The duration of each state is defined in Figure Q.26.
Q.7.8

R-SEGUE1 (supplements 10.7.1)

The maximum duration of R-SEGUE1 is 14 symbols (see Figure Q.22).
Q.7.8.1

R-REVERB3 (supplements 10.7.2)

The ATU-R shall start R-REVERB3 aligned with the beginning of a Hyperframe.
Q.7.8.2

R-SEGUE2 (supplements 10.7.3)

The duration of R-SEGUE2 is 13 symbols.
Q.7.8.3

R-MEDLEY (replaces 10.7.8)

R-MEDLEY is a wideband pseudo-random signal used for estimation of the upstream SNR at the ATU-C. The data to
be transmitted are derived from the pseudo-random sequence PRUm defined as:
d n = 1 for n = 1 to 23 and d n = d n-18 ⊕ d n-23 for n> 23.
In contrast to R-REVERB1, the cyclic prefix is used and the data sequence continues from one symbol to the next (i.e.

- 184 -

d1 to d23 are not re-initialized for each symbol). Because the sequence is of length 223-1, and 2*(nn-5) bits are used foreach symbol (where nn is the maximum subcarrier specified for PSD mask EU-nn in Table Q.18), the subcarrier vector
for R-MEDLEY changes from one symbol period to the next. Following R-MEDLEY the ATU-R enters signalling state
R-REVERB4. The duration of R-MEDLEY is as shown in Figure Q.26.
With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure Q.23. ATU-R shalltransmit the signal in both of NEXTC and FEXTC symbols, and ATU-C shall estimate two SNRs from the received
NEXTC and FEXTC symbols, respectively, as defined in Figure Q.25.
The following numerical formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > b) and (S + 271 < c) }if { (S + 271 < a) }where a = 1148, b = 1315, c = 2608

then symbol for estimation of FEXTC SNR
then symbol for estimation of NEXTC SNRWhen Bitmap-NC is disabled (FEXT Bitmap mode), the ATU-R shall not transmit NEXTC symbol. The number of bitsof NEXTC shall be no more than the number of bits of FEXTC.
At the transmitter, the PRUm sequence generator shall continue to be updated during NEXTC symbols when BitmapNC is disabled (FEXT Bitmap mode).

- 185 -

TTR R
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

101

10

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

11
12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

137

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

172

17

173

174

175

176

177

178

179

180

181

182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

206

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

243

24

244

245

246

247

248

249

250

251

252

253

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

275

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

T1535290-00

Symbol for estimation of FEXT C S/N

Symbol not used for S/N estimation

Symbol for estimation of NEXT C S/N

Figure Q.25/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Upstream- 186 -

Q.7.8.4

R-MSG1 (supplements 10.7.6)

Table Q.14/G.992.1 – Assignment of 48 bits of R-MSG1
Parameter (Note 2)
Suffix(ces) of mi (Note 1)
47-18
Reserved for future use

17
Trellis coding option
16
Overlapped spectrum option (Note 3)
15
Unused (shall be set to "1")14
Support of S = 1/2 mode (see Q.4.9) (Note 4)
13
Support of dual latency downstream
12
Support of dual latency upstream
11
Network Timing Reference
10, 9
Framing mode
8-5
Reserved for future use
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
NOTE 3 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
NOTE 4 – Since the S=1/2 mode is mandatory for Annex Q, a modem supporting Annex Q shall set this bit to binaryONE.

Q.7.8.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.7.6.6)

The Nupmax (transmit) capability is encoded onto {m4 , ..., m0} with a conventional binary representation (e.g.
100012 = 17).
Q.7.9

Exchange – ATU-C (supplements 10.8)

During C-RATESn, C-MSGn, C-B&G, and C-CRCn, the ATU-C shall transmit the FEXTR symbol. In the other signals,
the ATU-C shall transmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), andshall not transmit the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The
duration of each state is defined in Figure Q.27.

- 187 -

Q.7.9.1

C-MSG2 (supplements 10.8.9)

Replace Table 10-13 with Table Q.15.

Table Q.15/G.992.1 – Assignment of 32 bits of C-MSG2
Suffix(ces) of mi (Note 1)

Parameter (Note 2)

31-26

Estimated average loop attenuation

25-21

Reserved for future use

20-16

Performance margin with selected rate option

15-11

Reserved for future use

10-0

Total number of bits supported

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
For NSCus=32,
n1C-MSG2 = 43
n2C-MSG2 = 91
Otherwise,
n1C-MSG2 = 139
n2C-MSG2 = 187
Q.7.9.1.1

Total number of bits per symbol supported (replaces 10.8.9.3)

The ATU-C receiver shall also calculate the maximum number of bits per symbol that the upstream channel can support−7

with the performance margin defined in C-MSG-RA at an error rate of 10 .
The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTC and
NEXTC downstream channel performance [e.g. if the maximum numbers of bits that can be supported in FEXTC and
NEXTC symbols are 111 and 88 {Total number of bits per symbol supported} = (111 x 126 + 88 x 214)/340 = 96]. This
number is encoded into bits 10-0 using a conventional binary representation [e.g. if the maximum number of bits thatcan be supported is 96 (data rate = 384 kbit/s), {m10, ..., m0} = 000011111112].
NOTE – The number of symbols per hyperframe is 340. The number of FEXT symbols is 126. The number of NEXTsymbols is 214.
Q.7.9.1.2

Estimated average upstream loop attenuation (supplements 10.8.9.1)

For Annex Q-EU, see A.3.2.

Q.7.9.2

C-B&G (replaces 10.8.13)

C-B&G shall be used to transmit to the ATU-R the bits and gains information, Bitmap-FC {b1, g1, b2, g2, ... bNSCus-1,
gNSCus-1}, and Bitmap-NC {bNSCus+1, gNSCus+1, bNSCus+2, gNSCus+2, ..., b2*NSCus-1, g2*NSCus-1}, that are
to be used on the upstream carriers. bi of Bitmap-FC indicates the number of bits to be coded by ATU-R transmitter
onto the i th upstream carrier in FEXTC symbols; gi of Bitmap-FC indicates the scale factor, relative to the gain thatwas used for that carrier during the transmission of R-MEDLEY, that shall be applied to the i th upstream carrier in
FEXTC symbols. Similarly, bi of Bitmap-NC indicates the number of bits onto the (i – NSCus) th upstream carrier in- 188 -

NEXTC symbols; gi of Bitmap-NC indicates the scale factor that shall be applied to the (i – NSCus) th upstream carrierin NEXTC symbols.
Because no bits or energy will be transmitted at DC or one-half the sampling rate, b0, g0, bNSCus, gNSCus, b2*NSCus,
and g2*NSCus are all presumed to be zero and shall not be transmitted.
Each bi shall be represented as an unsigned 5-bit integer, with valid bis lying in the range of zero to Nupmax, themaximum number of bits that the ATU-R is prepared to modulate onto any subcarrier, which is communicated in
R-MSG1.
Each gi shall be represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of
the third most significant bit. For example, a gi with binary representation (most significant bit listed first)
001.010000002 would instruct the ATU-R to scale the constellation for carrier i, by a gain factor of 1.25, so that thepower in that carrier shall be 1.94 dB higher than it was during R-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
Let NSCu=128, except when EU-32 is used where NSCu=32. The C-B&G information shall be mapped in a32*(NSCu-1)-bit [4*(NSCu-1) byte] message m defined by:
m = {m32*(NSCu-1)-1, m32(NSCu-1)-2, …, m1, m0} = { g2*NSCu-1, b2*NSCu-1, …, gNSCu+1, bNSCu+1,
gNSCu-1, bNSCu-1, …, g1, b1},
(C.10-2)
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in
4*(NSCu-1) FEXTR symbols. When NSCu=32, including C_CRC5, the total length is 336 symbols while for
NSCu=128, the total length is 336+3*345=1371 symbols, using the transmission method as described in 10.8.9.
When Bitmap-NC is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NC shall be set to zero.
For index between NSCus+1 and 127, the m values are set to 0.
Q.7.9.3

C-SEGUE3 (replaces 10.8.16)

The duration of C-SEGUE3 is 18 symbols. Following C-SEGUE3, the ATU-C completes the initialization and enters
C-SHOWTIME. In C-SHOWTIME, ATU-C shall transmit the signal using Bitmap-FR and Bitmap-NR with the sliding
window.
When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbols.

- 189 -

Q.7.9.4

C-RATES-RA (supplements 10.8.3)
Table Q.16/G.992.1 – RRSI fields of C-RATES-RA←⎯⎯⎯⎯⎯ bits ⎯⎯⎯⎯→
fields7

6

RSF

B10 (AS0)

0

5

4

3

2

1

value of RSF
MSB

RSI

B8 (AS0)LSB

B9 (AS0)

value of RSI
MSB

S

I9

LSB

I8

value of S
MSB

I

I7

I6

FS(LS2)

0

I5

LSB
I4

I3

I2

I1

I0

value of FS(LS2) set to {000000002}

The RSI field has been extended to include bit B9 of BI (AS0) in bit 6, and The RSF field has been extended to include
the most significant bit B10 of BI (AS0) in bit 7, BI (AS0) being the number of payload bytes in the AS0 bearer channel
in the downstream interleave buffer. This is to support the higher data rates for the S=1/4, S=1/6 and S=1/8 modes.
The S field shall be coded {1001002) to indicate S=1/4, {1001102} to indicate S=1/6, and {1010002) to indicate S=1/8.
For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7.10Exchange – ATU-R (supplements 10.9)

ATU-R shall transmit only the FEXTC symbols in R-MSGn, R-RATESn, R-B&G, R-CRCn. In other signals, the
ATU-R shall transmit both FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shallnot transmit NEXTC symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is definedin Figure Q.27.
Q.7.10.1

R-MSG-RA (supplements 10.9.2)

Replace Table 10-15 with Table Q.17.

- 190 -

Table Q.17/G.992.1 – Assignment of 80 bits of R-MSG-RA (Annex Q-EU)
Suffix(ces) of mi(Note)
79-72
71 - 70
69, 68
67-56

Parameter
All reserved bits shall be set to 0
Reserved for ITU-T
Extension to number of RS payload bytes, K
Extension to number of tones carrying data (ncloaded)
Bfast-max

55-49
48-40
39-32
31-25
24-21
20-16

Number of RS overhead bytes, (R)
Number of RS payload bytes, K
Number of tones carrying data (ncloaded)
Estimated average loop attenuation
Coding gain
Performance margin with selected rate option

15 - 14

Extension to total number of bits per DMT symbol, Bmax

13-12
11-0

Maximum Interleave Depth downstream
Total number of bits per DMT symbol, Bmax

NOTE – Within the separate fields the least significant bits have the lowest subscripts.

Q.7.10.1.1

Total number of bits supported (Bmax) (replaces 10.9.2.8)

This parameter shall be defined as in R-MSG2, see Q.7.9.1.
Q.7.10.1.2

Bfast-max (new)Bfast-max is the maximum number of bits of the fast buffer for fast data transmitted on the condition that the bits of thefast data can be equally assigned to all FEXT-symbols and NEXT-symbols.
Fast Buffered Data Bfast-max is tf.
Q.7.10.2

R-MSG2 ( supplements 10.9.8)

Table Q.18/G.992.1 – Assignment of 32 bits of R-MSG2
Suffix(ces) of mi (Note 1)
Parameter (Note 2)
31-25
Estimated average loop attenuation
24-21
Reserved for future use
20-16
Performance margin with selected rate option
15 - 14
13-12
11-0

Extension to total number of bits per DMT symbol, Bmax
Reserved for future use
Total number of bits per DMT symbol, Bmax

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
N1R-MSG2 = 10
N2R-MSG2 = 20
Q.7.10.2.1

Total number of bits per symbol supported (supplements 10.9.8.3)

The maximum number of bits per symbol that the downstream channel can support is encoded into bits 15, 14 and 11 –0.

- 191 -

The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTR and
NEXTR downstream channel performance. For example, if the maximum numbers of bits that can be supported in
FEXTR and NEXTR symbols are 111 and 88, the total number of bits per symbol supported is (111 x 126 + 88 x
214)/340 = 96.
NOTE – The number of symbols per hyperframe is 340, the number of FEXT symbols is 126, and the number of NEXTsymbols is 214.
Q.7.10.2.2 Estimated average downstream loop attenuation (supplements 10.9.8.1)
For Annex Q-EU, see A.3.3.
Q.7.10.3 R-REVERB5 (supplement of 10.9.12)
The duration of R-REVERB5 is 345n-40, 3<=n<=19, when NSCu=128, or 3<=n<=16 when NSCu=32.

Q.7.10.4

R-B&G (replaces 10.9.14)

The purpose of R-B&G is to transmit to ATU-C the bits and gains information, Bitmap-FR {b1, g1, b2, g2, ...,bNSCds-1, gNSCds-1}, and Bitmap-NR {bNSCds+1, gNSCds+1, bNSCds+2, gNSCds+2, ..., b2*NSCds-1,
g2*NSCds-1}, to be used on the downstream subcarriers. bi of Bitmap-FR indicates the number of bits to be coded by
ATU-C transmitter onto the i th downstream subcarrier in FEXTR symbols; gi of Bitmap-FR indicates the scale factor
that shall be applied to the i th downstream subcarrier in FEXTR symbols, relative to the gain that was used for thatcarrier during the transmission of C-MEDLEY. Similarly, bi of Bitmap-NR indicates the number of bits onto the (i –NSCds) th downstream carrier in NEXTR symbols; gi of Bitmap-NR indicates the scale factor that shall be applied tothe (i – NSCds) th downstream carrier in NEXTR symbols. Because no bits or energy will be transmitted at DC or
one-half the sampling rate, b0, g0, bNSCds, gNSCds, b2*NSCds, and g2*NSCds are all presumed to be zero, and are
not transmitted. When subcarrier 64 is reserved as the pilot tone, b64 and bNSCds+64, shall be set to 0, g64 andgNSCds+64 shall be set to gsync. When subcarrier 96 is reserved as the pilot tone, b96 and bNSCds+96, shall be set to0, g96 and gNSCds+96 shall be set to gsync. When subcarrier 128 is reserved as the pilot tone, b128 and bNSCds+128,
shall be set to 0, g128 and gNSCds+128 shall be set to gsync. When subcarrier 256 is reserved as the pilot tone, b256
and bNSCds+256, shall be set to 0, g256 and gNSCds+256 shall be set to gsync.The value gsync represents the gain
scaling applied to the sync symbol.
Each bi is represented as an unsigned 5-bit integer, with valid bi lying in the range of zero to Ndownmax, the maximum
number of bits that the ATU-C is prepared to modulate onto any subcarrier, which is communicated in C-MSG1.
Each gi is represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of thethird most significant bit. For example, a gi with binary representation (most significant bit listed first) 001.010000002
would instruct the ATU-C to scale the constellation for carrier i by a gain factor of 1.25, so that the power in that carrier
shall be 1.94 dB higher than it was during C-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
The R-B&G information shall be mapped in a (2*NSCds-2)*16-bit ((2*NSCds-2)*2 byte) message m defined by:
m = {m(2*NSCds-2)*16-1, m(2*NSCds-2)*16-2, …, m1, m0} = { g2*NSCds-1, b2*NSCds-1, …, g NSCds+1, b(Q.10-3)
NSCds+1, g NSCds-1, b NSCds-1, …, g1, b1},
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in(2*NSCds-2)*2 symbols, using the transmission method as described in 10.9.8.

- 192 -

When Bitmap-NR is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NR shall be set to zero.
Q.7.10.5

R-SEGUE5 (replaces 10.9.17)

The duration of R-SEGUE5 is 13 symbols. Following R-SEGUE-5, ATU-R completes the initialization and enters
R-SHOWTIME. In R-SHOWTIME, ATU-R shall transmit the signal using Bitmap-FC and Bitmap-NC with the sliding
window.
When Bitmap-NC is disabled (FEXT Bitmap mode), ATU-R shall not transmit NEXTC symbols.

- 193 -

ATU-CC-FLAG2(G.994.1)

C-GALF2(G.994.1)≥ 128≤ 2048C-QUIET2(Note 5)345n(n ≤ 38)

ATU-R

If R-ACK2then
C-PILOT1

If R-ACK1then
C-PILOT1AR-GALF2(G.994.1)

Beginning ofHyperframe

R-QUIET2≤ 15500

345n(1 ≤ n ≤ 33)≤ 32
Beginning ofHyperframe

1725

C-QUIET3A(Note 2)

R-FLAG2(G.994.1)

R-REVERB1
1536

C-REVERB1
12477(Note 5)9216

C-PILOT2(Note 4)

1536

C-ECT

(Note 2)

(Note 5)4608

C-REVERB2

1536

If R-ACK2 then C-PILOT3
If R-ACK1 then C-QUIET53628

C-REVERB3

20

C-SEGUE1

2884

C-RATES1/C-CRC1
C-MSG1/C-CRC2

Last symbol
may beshortened byn samples

R-QUIET3≥ 6144≤ 6145

R-ECT

1536

R-REVERB2≥ 3634≤ 3643

R-SEGUE1

5 ≤, ≤ 14(Note 2)

(Note 1)Introduction ofguard time

R-REVERB3
345n + 208(0 ≤ n ≤ 7)

49152
C-MEDLEY

345n - 13(9 ≤ n ≤ 16)
R-SEGUE2

13

R-RATES1/R-CRC1
R-MSG1/R-CRC2

1254

R-MEDLEY

49152(Note 3)(Note 2)

T1532900-99

Figure Q.26/G.992.1 – Timing diagram of the initialization sequence – Part 1- 194 -

(Note 4)NOTE 1 – The ATU-C shall transmit the FEXTR symbols, and shall not transmit as NEXTR symbols except the pilot
tone.
NOTE 2 – The ATU-C shall transmit both FEXTR and NEXTR symbols, when Bitmap-NR is enabled (Dual Bitmapmode). ATU-C shall not transmit the NEXTR symbols except pilot tone, when Bitmap-NR is disabled(FEXT Bitmap mode).
NOTE 3 – The ATU-R shall transmit the FEXTC symbols, and shall not transmit the NEXTC symbols.
NOTE 4 – The ATU-R shall transmit both FEXTC symbols, when Bitmap-NC is enabled (Dual Bitmap mode).
ATU-R shall not transmit NEXTC symbols, when Bitmap-NC is disabled (FEXT Bitmap mode).
NOTE 5 – The ATU-C shall transmit both FEXTR and NEXTR symbols.

- 195 -

Figure Q.27/G.992.1 – Timing diagram of the initialization sequence – Part 2[Editor’s note: updated Figure Q.27 to parameterize the length of C-B&G and the maximum length of R-REVERB5.]
Q.8

AOC On-line adaptation and reconfiguration (pertains to clause 11)

Q.8.1.1

Bit swap request (replaces 11.2.3)

The receiver shall initiate a bit swap by sending a bit swap request to the transmitter via the AOC channel. This request
tells the transmitter which subcarriers are to be modified. The format of the request is shown in Table Q.19.

Table Q.19/G.992.1 – Format of the bit swap request message
Message header{111111112}(8 bits)

Bitmap index(1 bit)Message field 1-4
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

The request shall comprise nine bytes as follows:• an AOC message header consisting of 8 binary ones;• message fields 1-4, each of which consists of a one-bit bitmap index, subchannel index bits 10 & 9, and a five-bit
command followed by bits 8 to 1 of the subchannel index. One-bit bitmap index, subchannel index bits 10 & 9,
and valid five-bit commands for the bit swap message shall be as shown in Table Q.20. In Table Q.20, the MSB
for the bit swap request command represents the Bitmap index. For downstream data, Bitmap index equals 0
indicates Bitmap-FR, and Bitmap index equals 1 indicates Bitmap-NR. Similarly for upstream data, Bitmap
index equals 0 indicates Bitmap-FC, and 1 indicates Bitmap-NC. The next 2 bits are subchannel index bits 10 &9. The ten-bit subchannel index is counted from low to high frequencies with the lowest frequency subcarrier
having the number zero. The subcarrier index zero shall not be used;• the bit swap between FEXTC/R symbols and NEXTC/R symbols is not allowed.

Table Q.20/G.992.1 – Bit swap request commandValue(8 bit)yzz000002

Interpretation
Do nothing

yzz000012
yzz000102

Increase the number of allocated bits by one

yzz000112
yzz001002

Increase the transmitted power by 1 dB

yzz001012
yzz001102

Increase the transmitted power by 3 dB

yzz001112
yzz01xxx2

Reduce the transmitted power by 2 dB

Decrease the number of allocated bits by one
Increase the transmitted power by 2 dB
Reduce the transmitted power by 1 dB
Reserved for vendor discretionary commands

NOTE – y is "0" for FEXTC/R symbols, and "1" for NEXTC/R symbols of the Sliding Window.
NOTE – subchannel index = zz2*256 + subchannel index value from lower 8 bit field
The bit swap request message (i.e. header and message fields) shall be transmitted five consecutive times.
To avoid gi divergence between ATU-C and ATU-R after several bit swaps, for a gi update of ∆ dB the new gi value
should be given by:- 196 -

g i ' = (1 / 256) × round (256 × g i × 10 exp(∆ / 20))
Q.8.1.2(Q.11-1)

Extended bit swap request (supplements 11.2.4)

The format of the extended bit swap request is shown in Table Q.21.

Table Q.21/G.992.1 – Format of the bit swap request message
Message header{111111002}(8 bits)

Bitmap index(1 bit)Message field 1-6
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

In the same manner as the bit swap request, each of the message fields of the extended bit swap request consists of
one-bit bitmap index, a five-bit command followed by a related ten-bit subchannel index.
Q.8.1.3

Bit swap acknowledge (supplements 11.2.5)

The bit swap superframe counter number shall only indicate the last superframe (SPF#4) of a hyperframe.
The new bit and/or transmit power table(s) shall then take effect starting from the first frame (frame 0) of SPF#0 of a
hyperframe.
If the bit swap superframe counter number contained in the received bit swap acknowledge message does not indicate
SPF#4, then the new table(s) shall take effect starting from frame 0 of SPF#0 of the next hyperframe.
Q.9

POTS splitter

For operation according to G.992.1 Annex Q-EU, the Annex E.4/G.992.3 requirements applying over a frequency band
up to 1104 kHz, shall be met over a frequency band up to 3750 kHz.

- 197 -

資料４
G.992.1 ANNEX Q-EU (REVISION 4.0)
PROPRIETARY EXTENSION TO G.992.1 ANNEX I

This document defines G.992.1 Annex Q-EU (Quad spectrum downstream with extended upstream spectrum), a
proprietary extension to G.992.1 Annex I to extend the data rate beyond 32 Mbit/s downstream and 5 Mbit/s upstream
on short loops by way of:• Increased downstream bandwidth Æ increased number of subcarriers, NSCds=1024 (used subcarriers up to869)• Increase upstream bandwidth Æ increased number of subcarriers, NSCus=112• Increased bit loading, beyond 15 bits/bin• Extended framing Æ S=1/2n, with support for n = 1 to 4
Due to the increase in upstream data rates, the upstream maximum interleave depth has been increased to 16. Support ofthis is mandatory.
The attached text is the approved text for Annex I, marked up with revision control to show the changes necessary tosupport the additional functionality.
Revision R4 has the following changes with respect to Revision R3.2:• modified both downstream and upstream PSDs. Added EU-68 to 112.
• Modified timing diagram for initialization in Figure Q.27(Text in C-B&G and R-REVERB5 has been changed)• added G.994.1 code points to support above changes- 198 -

ANNEX Q-EU
Specific requirements for an ADSL system to support downstream data rates greater than 32 Mbit/s andupstream data rates greater than 5 Mbit/s on short loops operating in the same cable as ISDN as defined in
ITU-T Recommendation G.961 Appendix III

Q.1

Scope

This annex describes those specifications that are unique to an ADSL system coexisting in the same binder as
TCM-ISDN as defined Recommendation G.961 Appendix III. The subclauses in this annex provide supplementary andreplacement material to the clauses in the main body. The nature of the material is parenthetically indicated in the
subclause heading. The modifications described in this annex allow a performance improvement from the ADSL system
specified in Annex C for short loops in an environment coexisting with TCM-ISDN in the same cable. Specifically, thisAnnex specifies extensions to downstream and upstream bandwidth, framing modes, and maximum bit loading tosupport downstream data rates greater than 32 Mbit/s and upstream data rates greater than 5 Mbit/s. This annex also
defines those parameters of this ADSL system that have been left undefined in the main body of this Recommendation.
An ADSL system implementing Annex Q-EU shall support Annex Q. It is recommended that an ADSL system
implementing Annex Q-EU also implements Annexes I and C.
Q.2

Definitions

Bitmap-FC
Bitmap-FR
Bitmap-NC
Bitmap-NR
Dual Bitmap
FEXT Bitmap
FEXTC duration
FEXTC symbol
FEXTR duration
FEXTR symbol
Hyperframe
NEXTC duration
NEXTC symbol
NEXTR duration
NEXTR symbol
NSCds

NSCus
NSWF
Subframe
TTR
TTRC
TTRR
UI

ATU-R transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-R
ATU-R transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-R
The Dual Bitmap method has dual bit rates under the FEXT and NEXT noise from TCM-ISDN
Similar to the Dual Bitmap method however transmission only occurs during FEXT noise fromTCM-ISDN
TCM-ISDN FEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN FEXTTCM-ISDN FEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN FEXT
5 Superframes structure which synchronized TTR
TCM-ISDN NEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN NEXT
TCM-ISDN NEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN NEXT
The highest subcarrier index that can be used for downstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCds = 256 for a downstream
channel using the frequency band up to 1.104MHz; NSCds = 512 for a downstream channel
using the frequency band up to 2.208MHz.
The highest subcarrier index that can be used for upstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCus = 64 for an upstream
channel using the frequency band up to 276 kHz.
Sliding Window frame counter10 consecutive DMT symbols (except for sync symbols) according to TTR timing
TCM-ISDN Timing Reference
Timing reference used in ATU-C
Timing reference used in ATU-R
Unit Interval- 199 -

Q.3

Reference Models

Q.3.1

ATU-C transmitter reference model (replaces figures in 5.1)

See Figure Q.1 and Figure Q.2.
"Bits""Bits" &"Gains"
2*NSCds-1

AS0
AS1
AS2
AS3
LS0
LS1
LS2
NTR

crcf
Mux/
Sync
Control

crci

scram
&
FEC

scram
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

2*NSCds-2
480
IDFT

OutputParallel/
SerialBuffer

1
n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to NSCds-1
Constellation
Encoder Input
Data Frame

U-C

T1532760-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure Q.1/G.992.1 – ATU-C transmitter reference model for STM transport
Annex Q-EU does not currently support STM transport. It only supports ATM transport.

- 200 -

"Bits""Bits" &"Gains"
2*NSCds-1

AS0
ATM0

Cell TC
crcf

AS1
ATM1

Cell TC

NTR

Mux/
Sync
Control
crci

scram
&
FEC

scram
&
FEC

Rate
converterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

2*NSCds-2
480
IDFT
1

OutputParallel/
SerialBuffer

n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to NSCds-1
Constellation
Encoder Input
Data Frame

U-C

T1532770-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure Q.2/G.992.1 – ATU-C transmitter reference model for ATM transport- 201 -

Q.3.2

ATU-R transmitter reference model (replaces figures in 5.2)

See Figure Q.3 and Figure Q.4.

"Bits""Bits" &"Gains"LS02*NSCus-1
crcf

LS0
LS1

Mux/
Sync
ControlLS2

crci

scrambler&
FEC

scrambler
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

2*NSCus-2
59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR

B
FEC Output
Data Frame

Zi
i=1 to NSCus-1
C
Constellation
Encoder Input
Data Frame

U-R

T1532780-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (1.104 MHz).

Figure Q.3/G.992.1 – ATU-R transmitter reference model for STM transport
Annex Q-EU does not currently support STM transport. It only supports ATM transport.

- 202 -

"Bits"

2*NSCus-1

LS0
Cell TC

ATM0

LS1Cell TC

ATM1"Bits" &"Gains"

crcf
Mux/
Sync
Control
crci

scrambler&
FEC

scrambler&
FEC

2*NSCus-2

RateconverterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR
B
FEC Output
Data FrameZi
C
i=1 to NSCus-1
Constellation
Encoder Input
Data Frame

U-R

T1532790-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (1.104 MHz).

Figure Q.4/G.992.1 – ATU-R transmitter reference model for ATM transport- 203 -

Q.3.3

ATU-C/R transmitter timing model (replacement for 5.3)

Q.3.3.1

TCM-ISDN crosstalk timing model (new)Figure Q.5 shows the timing chart of the crosstalk from TCM-ISDN.

TTR
377 UI
receive ISDN

transmit ISDNCO

0 ≤ propagation delay ≤ 16 UI
RT

6-7.5 UI

377 UI

receive ISDN

transmit ISDN

FEXTR

NEXTR

SC
TTRC

ATU-C TX

Frame Frame0 ≤ propagation delay ≤ 18.5 UI

Received
TTRC

SR

TTRR
NEXTC
ATU-R TXFEXTC

Frame Frame
T1532800-99

1 UI = 3.125 µs
FEXTR and NEXTR are estimated by ATU-CFEXTC and NEXTC are estimated by ATU-R

TTR

TCM-ISDN timing reference

TTRC

Timing reference used in ATU-C

Received TTR C Received TTRC at ATU-R
TTRRTiming reference used in ATU-R

SC

55 × 0.9058 µs: Offset from TTR to TTRC

SR

–42 × 0.9058 µs: Offset from received TTRC to TTRR

Figure Q.5/G.992.1 – Timing chart of the TCM-ISDN crosstalk

The data stream of TCM-ISDN is transmitted in TTR period. CO transmits the stream in the first half of the TTR period
and RT transmits in the second half of the TTR period. ATU-C receives NEXT noise from the ISDN in the first half of
the TTR period and FEXT noise from the ISDN in the second half of the TCM-ISDN period. On the other hand,
ATU-R receives FEXT noise from the ISDN in the first half of the TTR period and NEXT noise from the ISDN in thesecond half of the TTR period.

- 204 -

As defined in Q.7.6.2 and Q.7.8.3, the ATU-C shall estimate the FEXTR and NEXTR duration at ATU-R, and the
ATU-R shall estimate FEXTC and NEXTC duration at ATU-C taking propagation delay on the subscribe line into
consideration.
The ATU-C shall transmit any symbols by synchronizing with the TTRC. The ATU-R shall transmit any symbols
synchronizing with the TTRR generated from received TTRC.
Q.3.3.2

Sliding window (new)Figure Q.6 shows the timing chart of the transmission for the Annex Q-EU downstream at ATU-C.
Hyperframe = 345 symbols

TTRC
Crosstalk
period

FEXTR

FEXTR

FEXTR

FEXTR
NEXTR

NEXTR

ATU-C
T Frame
SWB
T1532810-99

FEXTR symbol
NEXTR symbol

Sliding Window

Figure Q.6/G.992.1 – Sliding window for downstream symbols

The Sliding Window defines the transmission symbols under the crosstalk noise environment synchronized to theperiod of TTR. The FEXTC/R symbol represents the symbol completely inside the FEXTC/R duration. The NEXTC/R
symbol represents any symbol containing the NEXTC/R duration. Thus, there are more NEXTC/R symbols than
FEXTC/R symbols.
The ATU-C decides which transmission symbol is FEXTR or NEXTR symbol according to the sliding window andtransmits it with the corresponding bit table. Similarly, the ATU-R decides the transmission symbol is a FEXTC or
NEXTC and transmits it with the corresponding bit table. Although the phase of the sliding window is asynchronouswith TTRC/R, the pattern is fixed to the 345 frames of the hyperframe.
Q.3.3.3

ATU-C Symbol Synchronization to TTR (new)345 symbols are 34 cycles with cyclic prefix of TTRC (or 32 cycles of TTRC without cyclic prefix). This implies a PLL
lock at the ATU-R.
Q.3.3.4

Dual Bitmap switching (new)The ATU-C transmits FEXTR symbols using Bitmap-FR (in FEXTR duration), and transmits NEXTR symbols using
Bitmap-NR (in NEXTR duration) according to the result of initialization. The ATU-R transmits FEXTC symbols using
Bitmap-FC (in FEXTC duration), and transmits NEXTC symbols using Bitmap-NC (in NEXTC duration) in the samemanner.
The ATU-C shall have the capability to disable Bitmap-NC and Bitmap-NR (see Q.4.5 and Q.5.3).

- 205 -

Q.3.3.5

Loop timing at ATU-R (new)The phase relation between received symbol and transmitted symbol of ATU-R at the reference point U-R shall meetthe phase tolerances as shown in Figure Q.7.
(point U-R)
ATU-R receive
DMT symbol

ATU-R transmit
DMT symbol
T1532820-99±4.5 µs + SR

Figure Q.7/G.992.1 – Loop timing for ATU-R

Q.4

ATU-C functional characteristics (pertains to clause 7)

Q.4.1

STM transmission protocols specific functionality (pertains to 7.1)

Q.4.1.1

ATU-C input and output V interface for STM transport (replaces figure in 7.1.1)

See Figure Q.8.

- 206 -

AS0 (n0 × 32 kbit/s)
AS1 (n1 × 32 kbit/s)
AS2 (n2 × 32 kbit/s)
AS3 (n3 × 32 kbit/s)
Digital
Network

twisted pair

LS0 ("C"; 16 or m0 × 32 kbit/s)

ATU-C

LS1 (m1 × 32 kbit/s)
LS2 (m2 × 32 kbit/s)
NTR
TTR
Operations, maintenance and control

T1532830-99

V-C
NOTE 1 – Optional bearer channels (both duplex and simplex) and features are shown with dotted lines.
NOTE 2 – TTR may be generated in the ATU-C without being provided from the V-C reference point.

Figure Q.8/G.992.1 – ATU-C functional interfaces for STM transport at the V-C reference point

Q.4.1.2

Payload transfer delay (supplements 7.1.4)

Since Annex Q-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.1.4.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
Q.4.2
Q.4.2.1

ATM transmission protocols specific functionalities (pertains to 7.2)
ATU-C Input and Output V interface for ATM transport (replaces figure in 7.2.1)

See Figure Q.9.

- 207 -

ATM layer

ATM0
Tx_ATM0P
O
RT0

Tx_Cell_Handshake0
Rx_ATM0
Rx_Cell_Handshake0

ATM1
P
O
R
T
1

Twisted pair

Tx_ATM1
ATU-C
Tx_Cell_Handshake1
Rx_ATM1
Rx_Cell_Handshake1
NTR

and interface to
Digital network

TTR
Operations, administration,
maintenance and control
V-C

T1532840-99

NOTE – TTR can be generated in the ATU-C without being provided from the V-C reference point.

Figure Q.9/G.992.1 – ATU-C functional interfaces to the ATM layer at the V-C reference point

Q.4.2.2

Payload transfer delay (supplements 7.2.2)

Since Annex Q-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.2.2.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
Q.4.3
Q.4.3.1

Framing (pertains to 7.4)
Superframe structure (supplements 7.4.1.1)

Since the rate converter reorders the user data and overhead bit-level data to create hyperframes, the input data frames
to the constellation encoder are different than those defined in 7.4.1.1.
Q.4.3.2

Hyperframe structure (replaces 7.4.1.3)

Annex Q-EU uses the hyperframe structure shown in Figure Q.10. Figure Q.10 shows the phase relationship between
the TTRC and the hyperframe at the point U-C. Each hyperframe is composed of 5 superframes, which are numberedfrom 0 to 4. In order to indicate the boundary of the hyperframe, the inverse synch symbol is used for the 4thsuperframe (SPF#3), which is generated from a tone-by-tone 180-degree phase reversal of the synchronization symbol(see Q.4.7.1) except for the pilot tone.
The bit-level data stream from the rate-converter is extracted according to the size of Bitmap-FR and Bitmap-NR using
the Sliding Window (see Q.3.3.2).
In order to make the bit rate to be a multiple of 32 kbit/s, the dummy bits are inserted at the end of hyperframe by the- 208 -

rate converter (see Q.4.4.2). The hyperframe is composed of 345 DMT symbols, numbered from 0 to 344. Each symbol
is assigned as FEXTR or NEXTR symbol in a FEXTR or NEXTR duration (see Q.2), and the following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-C transmitter (see Figure Q.11).
For Ndmt = 0, 1, ..., 344

S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > a + b) }elsethen FEXTR symbol
then NEXTR symbol

where a = 1243, b = 1461
Thus, 128 DMT symbols are allocated in the FEXTR duration, and 217 DMT symbols are allocated in the NEXTR
duration. The symbols are composed of:
FEXTR symbol:
Number of symbol using Bitmap-FR
Number of synch symbol
Number of inverse synch symbol
NEXTR symbol:

= 126
=1
=1

Number of symbol using Bitmap-NR= 214

Number of synch symbol=3

During FEXT Bitmap mode, the ATU-C shall transmit only the pilot tone in NEXTR symbols.

- 209 -

5 Superframe (= 340 frames)(point B)
1 Superframe = 68 frames (17 ms)

1 frame = 250 µs
Rate-Converter(point U-C, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#27

TC#33

TTR
ATU-R
Crosstalk

NEXT

FEXT

FEXT

Hyperframe = 345 symbols (85 ms)
SPF#1

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol F F F F N N N N N N F F

SSliding window

SPF#2
S

S

SPF#3
N F I

Inverse synch symbol

S

NEXTR Synch symbol

F

Symbol using Bitmap-FR (FEXTR duration bitmap)

N

Symbol using Bitmap-NR (NEXTR duration bitmap)

S

FEXTR Synch symbol

Figure Q.10/G.992.1 – Hyperframe structure for downstream- 210 -SPF#4
F F

FEXTR duration

1 symbol = 246 µs
I

NEXT

N
T1532850-99

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

0
10
20
30

1

2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
21
22
23
24
25
26
27
28
29
40
31
32
33
34
35
36
37
38
39
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
SS
61
62
63
64
65
66
67
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100 101
101 102
103
104
105
106
107
108
109
110 111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
SS
132
133
134
135
136
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162 163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181 182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
SS
203
204
205
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233 234
235
236
237
238
239
240
241
242 243
253
244
245
246
247
248
249
250
251
252
263
254
255
256
257
258
259
260
260
262
264
265
266
267
268
269
270
271
272
273
274
276
277
278
279
280
281
282
283
ISS
284
285
286
287
288
289
290
291
292
293
295
296
297
298
299
300
301
302
303
294
304 305
306
307
308
309
310
311
312
313 314
315
316
317
318
319
320
321
322
323
324
334
325
326
327
328
329
330
331
332
333
SS
335
336
337
338
339
340
341
342
343
ISS

Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol
NEXTR data symbol

SS

NEXTR synch symbol
T1535330-00

Figure Q.11/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Downstream

Q.4.3.3

Subframe Structure (replaces 7.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table Q.1. The 34 subframes forma hyperframe.

- 211 -

Table Q.1/G.992.1 – Subframe (downstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

Q.4.3.4

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Inverse Synch Symbol#344 is Synch Symbol

Reduced overhead framing with merged fast and sync bytes (modifies 7.4.3.2)

In S=1/2n framing mode (see §Q.4.9), there are n Sync bytes per symbol time. The contents of the Sync bytes is thesame as in regular framing except that it repeats at n times the rate causing the superframe to be 68/n symbols in length.
The contents of the sync bytes are shown in Table 7-6/G.992.1. In S=1/2n framing mode, “Frame Number” in column 1
in Table 7-6/G.992.1 is replaced by “Sync Byte Index Number”.
As a result of the increase in superframe rate, the superframe contents is carried more frequently. For the case when
N=2, the EOC and AOC bandwidth doubles, thereby transferring actual messages at twice the rate. The CRC byte iscarried twice as frequently and therefore the maximum error rate rises from just over 58 per second to 117 per second.
Where the duration of an error condition is measured, this needs to be taken into consideration. The indicator bits arealso sent twice as often, which needs to be taken into consideration for statistics collection.
Q.4.4

Dual Bitmapping and Rate Conversion (replaces 7.15)

The functions of the rate converter (see Q.4.4.2), tone ordering (see Q.4.6), constellation encoding, and gain scaling
shall use one of two bitmaps stored in the ATU. This method is called the dual bitmap.

- 212 -

Q.4.4.1

Dual Bitmap (new)The Dual Bitmap method has individual bit rates under the FEXT and NEXT noise, and this needs an additional bit andgain table, {bi, gi}, and ordered bit table, b'i, for the tone ordering. The dual bitmaps are switched synchronized withthe sliding window pattern of NEXT/FEXT symbols. The number of bits and the relative gains to be used for every tone
are calculated in the bit loading algorithm during the initialization sequence, and transmitted in R-B&G.
Q.4.4.2

Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FR, Bitmap-NR and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amount of fast and interleaved data in Bitmap-FR and Bitmap-NR shall be calculated with thefollowing formulae and illustrated in Figure Q.12:
If tRf ≤ nRmax:n Rf = t Rf
nRi = nR − nRf
f Rf = t Rf
f Ri = f R − f Rf
If tRf > nRmax:

nRf = nR max

nRi = 0⎧⎡ t Rf × 10 − nRf × 6 ⎤⎪ f Rf 4 = ⎢
⎥
4
⎪
⎢
⎥
f Rf = ⎨⎡ t Rf ×10 − nRf × 7 ⎤⎪⎥⎪ f Rf 3 = ⎢3⎢⎥⎩⎧⎪ f Ri 4 = f R = f Rf 4
f Ri = ⎨⎪⎩ f Ri3 = f R − f Rf 3
Where:
tRf
tRi
fRf and nRf
fRf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FR and Bitmap-NR, respectively.
is the number of fast bits in Bitmap-FR if the subframe (see Q.4.3.3) contains 3 Bitmap-FR except
for synch symbols.
fRf4
is the number of fast bits in Bitmap-FR if the subframe contains 4 Bitmap-FR except for synch
symbols.
fRi and nRi
are the numbers of interleaved bits in Bitmap-FR and Bitmap-NR, respectively.
nR
is the number of total bits in Bitmap-NR, which is specified in the B&G tables.
During FEXT Bitmap mode, nRf and nRi are zero.
To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tRf ≤ nRmax:- 213 -

dummy Rf = 0

dummy Ri = ( f Ri × 126 + nRi × 214) − t Ri × 340

If tRf > nRmax:()
dummy Rf 3 = ( f Rf × 3 + nRf × 7 ) − t Rf × 10

dummy Rf 4 = f Rf × 4 + nRf × 6 − t Rf ×10

dummy Ri = ( f Ri 4 × 96 + f Ri3 × 30 ) − t Ri × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FR constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:

dummy SRf = f Rf 3 − f Rf 4
The receiver shall determine Bitmap-FR and Bitmap-NR so that dummyRi is less than 126, dummyRf4 is less than 4 anddummyRf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.

- 214 -

#335#336#337#338#339#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25 #26 #27 #28 #29

tRi

Interleaved DatatRj

Fast Data

NOTE – Bit Ordering:
The earlier bit is located at the bottom
each symbol in this figure.
Rate Converter

Order

When tRf ≤ nRmax

fRi =fR – fRf

fR#4 #5 #6 #7 #8 #9

dummyRi#21 #22 #23#10 #11 #12 #13#0 #1 #2 #3#14 #15 #16 #17 #18 #19 #20#343#339#340#341#342#24 #25 #26 #27 #28 #29

nRinnRf=tRf R

fRf – tRf
FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe

When tRf > nRmax#0 #1 #2 #3#21 #22 #23#10 #11 #12 #13

dummyRi

fRi3

fRi4
dummyRf4

fR#335#336#337#338

dummyRf4

dummyRf3

dummy Rf4

fRf3
fRf4

#4 #5 #6 #7 #8 #9#14#15 #16 #17#18 #19 #20#26 #27 #28 #29#339#340#341#342#343

nRf = n
FEXTNEXT
Symbols Symbols
Subframe

FEXT
Symbols

NEXT
Symbols

Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe
T1532860-99

Figure Q.12/G.992.1 – Bit distribution for Rate Converter under Dual latency and Dual Bitmap mode

Q.4.5

FEXT Bitmapping (replaces 7.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (Q.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures Q.10 and Q.16).
Annex Q-EU does not support the FEXT Bitmapping mode.
Q.4.6

Tone Ordering (replacement for 7.7)

A DMT time-domain signal has a high peak-to-average ratio (its amplitude distribution is almost Gaussian), and large
values may be clipped by the digital-to-analogue converter. The error signal caused by clipping can be considered as anadditive negative impulse for the time sample that was clipped. The clipping error power is almost equally distributed
across all tones in the symbol in which clipping occurs. Clipping is therefore most likely to cause errors on those tones- 215 -

that, in anticipation of a higher received SNR, have been assigned the largest number of bits (and therefore have thedensest constellations). These occasional errors can be reliably corrected by the FEC coding if the tones with the largest
number of bits have been assigned to the interleave buffer.
The numbers of bits and the relative gains in two bitmaps to be used for every tone are calculated in ATU-R receiver,and sent back to ATU-C according to a defined protocol (see 10.9.14). The pairs of numbers are typically stored, in
ascending order of frequency or tone numbers i, in bit and gain tables for Bitmap-FR and Bitmap-NR.
For Bitmap-FR, the "tone-ordered" encoding shall first assign fRf bits from the rate converter (see Q.4.4.2) to the tones
with the smallest number of bits assigned to them, and the remaining fRi bits to the remaining tones. For Bitmap-NR, it
shall first assign nRf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nRi bits to the remaining tones.
All tones shall be encoded with the number of bits assigned to them; one tone in each bitmap may therefore have a
mixture of bits from the fast and interleaved buffers.
The ordered bit tables b'iF and b'iN shall be based on the original bit tables biF and biN as follows:
For k = 0 to Ndownmax {From the bit table, find the set of all i with the number of bits per tone bi = k
Assign bi to the ordered bit allocation table in ascending order of i}
Two ordered bit tables for Bitmap-FR and Bitmap-NR shall be prepared. A complementary de-ordering procedure
should be performed in ATU-R receiver. It is not necessary, however, to send the results of the ordering process to thereceiver because the bit tables FR and NR were originally generated in ATU-R, and therefore those tables have all theinformation necessary to perform the de-ordering.
Q.4.7
Q.4.7.1

Modulation (pertains to 7.11)
Inverse Synchronization Symbol (replaces 7.11.4)

Except for the pilot tone, Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phasereversal of Synchronization symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
Q.4.7.2

Data subcarriers (modifies 7.11.1.1)

The channel analysis signal defined in 10.6.6 allows for a maximum of NSCds-1 carriers (at frequencies n∆f , n = 1 to
NSCds-1) to be used.
Q.4.7.3

Nyquist frequency (modifies 7.11.1.3)

The carrier at the Nyquist frequency (#NSCds) shall not be used for user data and shall be real valued; other possible
uses are for further study.
Q.4.7.4

Modulation by the inverse discrete Fourier transform (replaces 7.11.2)

The modulating transform defines the relationship between the 2*NSCds real values xn and the Zi:

xn =2* NSCds −1⎛ jπni ⎞∑ exp⎜⎝ NSCds ⎟⎠Zi =0i

for n = 0 to 2 * NSC − 1(7-21)The value of NSCds shall be 1024 for this Annex. However, the highest used subcarrier index shall be limited to 869.
The constellation encoder and gain scaling generate only NSCds-1 complex values of Zi. In order to generate realvalues of xn, the input values (NSCds-1 complex values plus zero at DC and one real value for Nyquist if used) shall beaugmented so that the vector Z has Hermitian symmetry. That is,- 216 -

Zi = conj (Z'2*NSCds-i)
Q.4.7.5

for i = NSCds+1 to 2*NSCds-1(7-22)

Synchronization symbol (modifies 7.11.3)

The synchronization symbol permits recovery of the frame boundary after micro-interruptions that might otherwise
force retraining.
The data symbol rate, fsymb = 4 kHz, the carrier separation, ∆f = 4.3125 kHz, and the IDFT size, N = 2*NSCds, aresuch that a cyclic prefix of 15.625%*NSCds samples could be used. That is, when NSCds = 256, there are 40 samples
in the cyclic prefix.
(512 + 40) × 4.0 = 512 × 4.3125 = 2208

(7-23)

The cyclic prefix shall, however, be shortened to 12.5%*NSCds samples, and a synchronization symbol (with anominal length of NSCds*2.125 samples) is inserted after every 68 data symbols. That is,(2 + 0.125)*NSCds × 69 = (2 + 0.15625)*NSCds × 68(7-24)
The data pattern used in the synchronization symbol shall be the pseudo-random sequence PRD, (dn, for n = 1 to
2*NSCds) defined by:
dn = 1for n = 1 to 9
(7-25)
dn = dn-4 ⊕ dn-9

for n =10 to 2*NSCds(7-26)

The first pair of bits (d1 and d2) shall be used for the DC and Nyquist subcarriers (the power assigned to them is zero,so the bits are effectively ignored); the first and second bits of subsequent pairs are then used to define the Xi and Yi for
i = 1 to NSCds-1 as shown in Table 7-13.
The period of the PRD is only 511 bits, so dn+511 is equal to dn. The d1-d9 shall be re-initialized for eachsynchronization symbol, so each symbol uses the same data.
The two bits that modulate the pilot carrier, shall be overwritten by {0,0}: generating the {+,+} constellation.
The minimum set of subcarriers to be used is the set used for data transmission (i.e. those for which bi > 0); subcarriers

for which bi = 0 may be used at a reduced PSD as defined in transmit PSD paragraphs of Annexes A, B and C. The data
modulated onto each subcarrier shall be as defined above; it shall not depend on which subcarriers are used.
Q.4.7.6

Cyclic prefix (replaces 7.12)

The last 12.5%*NSCds samples of the output of the IDFT (xn for n = 2*NSCds-0.125*NSCds to 2*NSCds-1) shall be
prepended to the block of 2*NSCds samples and read out to the digital-to-analogue converter (DAC) in sequence. For
example, when NSCds=256, the subscripts, n, of the DAC samples in sequence are 480 ... 511, 0 ... 511.
The cyclic prefix shall be used for all symbols beginning with the C-RATES1 segment of the initialization sequence, as
defined in 10.6.2.
Q.4.8

ATU-C Downstream transmit spectral masks (replaces 7.14)

The downstream spectral masks of Annex Q-EU are as specified in this section. When C-MSG1 bit 16 is 0, the PSD
mask as specified in § Q.4.8.1 shall be used. When C-MSG1 bit 16 is 1, the PSD mask as specified in § Q.4.8.2 shall be
used.
Q.4.8.1

Downstream non-overlapped PSD mask definition

The non-overlapped PSD masks are defined with absolute peak values in Figure Q.13. The low frequency stop band isdefined for frequencies below f1 kHz (tone n1); the high frequency stop band is defined at frequencies greater than3750 kHz (tone 869). The in-band region of these PSD masks is the frequency band from f1 kHz to 3750 kHz.

- 217 -

–18 dB/octave

PSD indBm/Hz–2.9 dB/octave–36.5 dBm/Hz peak PSD

36 dB/octave–44.2 dBm/Hz–357 dBm/Hz–100 dBm/Hz peak PSD
in 10 kHz window–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 3925 kHz–50 dBm/Hz–76.5 dBm/Hz–92.5 dBm/Hz–110 dBm/Hz
0

4

f3

f1

1104

3750
3925 4545

1622

Frequency band f (kHz)0<f<4
4 < f < f3
f3 < f < f1
f1 < f < 1104
1104 < f < 1622
1622 < f < 3750

Equation for line (dBm/Hz)
-97.5
-92.5
-92.5 + 36*log2(f/f3)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 2.9*log2(f/1622)

3750 < f < 3925
3925 < f < 12000-76.5 - 357*log2(f/3750)-100

Frequency (kHz)04
4

PSD level (dBm/Hz)
-97.5
-97.5
-92.5

Measurement BW
100 Hz100 Hz100 Hz

f3
f1
f1
1104
1622

-92.5
-44.2
-36.5
-36.5
-46.5

10 kHz
10 kHz
10 kHz
10 kHz
10 kHz3750
3750
3925 – 12000

-50
-76.5
-100

10 kHz
10 kHz
10 kHz- 218 -

–112 dBm/Hz

7225

12000

Frequency
in kHzAdditionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
3925
4545
7225
12000

PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

The corner frequencies f1 and f3 depend on the associated upstream PSD mask used, see §Q.5.6) and are defined asfollows:
Mask designator(DS-mm)
DS-32
DS-36
DS-40
DS-44
DS-48
DS-52
DS-56
DS-60
DS-64
Mask
designator
DS-68
DS-72
DS-76
DS-80
DS-84
DS-88
DS-92
DS-96
DS-100DS-104
DS-108
DS-112NOTE 1 –NOTE 2 –NOTE 3 –NOTE 4 –NOTE 5 –NOTE 6 –Associatedupstream mask
EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

Associated upstream
mask
EU-68
EU-72
EU-76
EU-80
EU-84
EU-88
EU-92
EU-96
EU-100EU-104
EU-108
EU-112f1 (kHz)f3 (kHz)138
155.25172.5
189.75207
224.25241.5
258.75
276

54.45
61.26
68.06
74.87
81.67
88.48
95.29
102.09108.9

Lower bound f1(kHz)
293.25310.5
327.75345
362.25379.5
396.75414
431.25448.5
465.75483

Stopband f3(kHz)115.71122.51129.32
136.12142.93149.74156.54163.35170.16176.96183.77190.57

All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint withfrequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued
the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that
this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.
Figure Q.13: Non-overlapped Downstream Channel PSD Masks

Spectral Shaping of the In-Band Region defined in Q.4.8.3 and Transmit Signals with Limited Transmit Power definedin Q.4.8.4 shall be applied.

Q.4.8.2

Downstream Overlapped PSD mask definition- 219 -

The overlapped PSD mask is defined with absolute peak values in Figure Q.14. The low frequency stop band is definedfor frequencies below 25.875 kHz (tone 6); the high frequency stop band is defined at frequencies greater than3750 kHz (tone 869). The in-band region of this PSD mask is the frequency band from 25.875 kHz to 3750 kHz.

–18 dB/octave

PSD indBm/Hz–36.5 dBm/Hz peak PSD–2.9 dB/octave–50 dBm/Hz

21 dB/octave–100 dBm/Hz peak PSD
in 10 kHz window–357 dBm/octave–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 3925 kHz–76.5 dBm/Hz–92.5 dBm/Hz–110 dBm/Hz
0425.8751104

3750
3925 4545

1622

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < 1104
1104 < f < 1622
1622 < f < 3750

Equation for line (dBm/Hz)-97.5-92.5 + 21*log2(f/4)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 2.9*log2(f/1622)

3750 < f < 3925
3925 < f < 12000-76.5 - 357*log2(f/3750)
-100

7225

Frequency (kHz)04
4
1025.8751104
1622

PSD level (dBm/Hz)
-97.5
-97.5
-92.5
interpolated
-36.5
-36.5
-46.5

Measurement Bandwidth
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz3750
3750
3925 – 12000

-50.0
-76.5
-100

10 kHz
10 kHz
10 kHz

Additionally, the PSD mask shall be satisfying following requirements:- 220 -

–112 dBm/Hz
12000

Frequency
in kHzFrequency (kHz)
3925
4545
7225
12000
NOTE 1 –NOTE 2 –NOTE 3 –NOTE 4 –NOTE 5 –NOTE 6 –PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement Bandwidth
1 MHz
1 MHz
1 MHz
1 MHz

All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint withfrequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at themeasurement frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at
frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask
continued the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It wasrecognized that this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.
Figure Q.14: Overlapped Downstream Channel PSD Mask.

Q.4.8.3

Spectral Shaping of the In-Band Region of the PSD Spectrum

In order to shape the ATU-C PSD, frequency dependent gains, called spectral shaping values (ssvi ), shall be applied oneach tone during initialization and showtime. The ssvi values shall be represented with 1 bit before and 10 bits after thedecimal point.
Table Q.2 defines the corner points for the nominal PSD shape of the inband region as gain in dB, i.e log_ssvi. Log_ssvi
on other tones shall be linearly interpolated between corner points on a logarithmic scale for the gain (dB) and a linear
scale for the frequency (Hz). Note that the corner points defined in Table Q.2 are relative values. Table Q.3 defines thesimilar corner points for the overlapped spectrum.
The spectral shaping values shall be converted from logarithmic scale (log_ssvi, dB values) to linear ssvi values
according to:log_ ssvi⎛⎞
Round ⎜⎜1024 × 10 20 ⎟⎟⎝⎠ssvi =
1024

These points are not passed at initialization for the nominal PSD shape but are provided here for reference. However,for additional spectral shaping (see Q.4.8.5), parameters are passed during G.994.1.
The combined accuracy of the process of linear interpolation of the log_ssvi values and the process of conversion tolinear ssvi values shall be strictly less than one half lsb of the 10 bit after the decimal point format of the linear ssvi
values. No error shall be introduced when log_ssvi equals 0dB or is interpolated between log_ssvi values, which equal
0dB.
NOTE 1:NOTE 2:

The above definition ensures that the maximum deviation between ssvi values used by transmitter andreceiver is one lsb.
The above needs an accuracy that is strictly < 1/2 lsb. An accuracy of = 1/2 lsb, will lead to inaccurate
results.

- 221 -

Table Q.2: Corner points for the non-overlapped nominal in-band PSD shape.
Tone Index
n1

Log_ssvi (dB)
0

256
376
869

0
–10
–13.5

Comments
f1 kHz defines the beginning of the inband region. No shaping is applied in the
low stop band.
1104 kHz
1622 kHz ( –10 = –50 – Nominal_PSD_lowband)
3750 kHz ( –13.5 = –53.5 - Nominal_PSD_lowband)

Table Q.3: Corner points for the overlapped nominal in-band PSD shape
Tone Index
6

Log_ssvi (dB)
0

256
376
869

0
–10
–13.5

Comments
25.875 kHz defines the beginning of the inband region. No shaping is appliedin the low stop band.
1104 kHz
1622 kHz (–10 = –50 – Nominal_PSD_lowband)
3750 kHz (–13.5 = –53.5 – Nominal_PSD_lowband)

The absolute values of the transmit PSD are obtained by scaling the relative shaping values with a
NOMINAL_PSD_lowband, defined for the lower in-band frequencies. Note that the nominal in-band transmit PSD isfrequency dependent. The NOMINAL_PSD_lowband is –40 dBm/Hz (below 1104 kHz) for both the overlapped andnon-overlapped spectra.
NOTE 3: In-band PSD spectral shaping is applied prior to the IFFT.
NOTE 4: The value of MAXNOMATPds may be limited by regional regulations.
Q.4.8.4

Transmit Signals with Limited Transmit PowerFor cases where the transmit signal must be limited to a maximum aggregate transmit power (e.g. ATPdsmax = +20dBm), thend)During initialization the PSD transmit level is specified as an offset from the nominal value, i.e.
(Nominal_PSD_lowband + ssvi – x – power cutback) dB, and all values of gi = 1 for the offset value x and power
cutback. The value of x shall be the greater of 0 dB and (21.1 – ATPdsmax) dB for non-overlapped and (21.5 –ATPdsmax) dB for overlapped. For ATPdsmax = 20 dBm, the corresponding value of x shall be 1.1 dB for nonoverlapped and 1.5 dB for overlapped cases.

b)

If bi>0, then valid range for gi is [-14.5 to +2.5+x] (dB) ;If bi>0, then gi shall be in the [gsync – 2.5 to gsync + 2.5] (dB) range;
If bi=0, then gi shall be equal to 0 (linear) or in the [-14.5 to gsync] (dB) range;
For G.992.1 Annex Q-EU, gsync <= x dB

The gi values shall be constrainted by following relation:
Constraint on gi values

2* NSCds −1
i =32

Q.4.8.5

2* NSCds −1∑ ssv ∗ g ≤ ∑ ssv
2

i

2

i

i =32

2
i

Additional inband spectral shaping

An ATU-R may request additional downstream inband spectral shaping by passing parameters to the ATU-C in a
G.994.1 MP, or MS message. The ATU-C may select additional downstream inband spectral shaping by passing
parameters to the ATU-R in a G.994.1 MS message. Within the framework of G.994.1, the ATU-C has the ability tomake the final decision on the downstream inband PSD shape to be used.
The additional inband spectral shaping parameters are listed in Q.7.2.2 and defined in Q.7.3. If the Additional inband
spectral shaping Spar(2) bit is set to ONE in Table Q.7.2, its associated Npar(3) octets in Tables Q.7.2.1 to Q.7.2.1.5
define the inband spectral shape. If the additional inband spectral shaping Spar(2) bit is set to ZERO, its associated- 222 -

Npar(3) octets are not transmitted and the nominal inband PSD shape defined in Q.4.8.3 shall be used. These Npar(3)octets define the downstream PSD levels in the low band (between f1 and 1104 kHz), at 1622 kHz and at 3750 kHz.
The PSD levels between 1104 kHz and 1622 kHz, and between 1622 kHz and 3750 kHz are linearly interpolated in log
scale. The defined values are the PSD level in dB below the NOMINAL_PSD_lowband of –40dBm/Hz. For example, if
all three values are set to 20 dB, the result will be a flat PSD of –60dBm/Hz. If the three values are set to 2 dB, 12 dB
and 15.5 dB, the result is the PSD defined in Q.4.8.1 reduced by 2dB. In order not to violate the PSD mask defined in
Q.4.8.1, the second value shall be no less than 10 dB and the third value shall be no less than 13.5 dB.

Q.4.8.6

Egress control

G.992.1 Annex Q-EU equipment shall be able to reduce the PSD below –80 dBm/Hz for the Amateur radio bands
between 1.81 MHz and 2.00 MHz, and between 3.5 MHz and 3.8 MHz. The ATU-C may apply additional spectral
shaping as described in Q.4.8.5 to help achieve this requirement.

Q.4.9

Support of higher downstream bit rates with S = 1/2n (replaces 7.6.4)

With a rate of 4000 data frames per second and a maximum of 255 bytes (maximum RS codeword size) per data frame,
the ADSL downstream line rate is limited to approximately 8 Mbit/s per latency path. The line rate limit can beincreased beyond this for the interleaved path by mapping 2n RS codewords into one FEC data frame (i.e. by using S =1/2n in the interleaved path). S = 1/2n shall be used in the downstream direction only over bearer channel AS0.
For a selected value of n ≥ 1, the KI data bytes per interleaved mux data frame shall be packed into 2n RS codewords,
split into n equal parts, each consisting of 2 consecutive RS codewords. This forces rate adaptation to occur in 32n
kbit/s increments. Each of the n parts of the data frame shall begin with a sync byte and shall obey the rules defined inTable Q.4 for insertion of dummy bytes. The smallest value of n that can support the KI data bytes shall be used.
Support of S = 1/2 (i.e., n=1), S = 1/4 (i.e., n=2), S = 1/6 (i.e., n=3), and S = 1/8 (i.e., n=4), is mandatory.
The resulting data frame structure shall be as shown in Figure Q.15.
N1
Sync
Byte

PayloadN2 = N 1 or N 1-1

R

PayloadR

N2n-1 = N1
Sync
Byte

PayloadN2n = N2

R

PayloadR

NI
Figure Q.15 – Data frame for S = 1/2n mode
When KI is divisible by 2n, the 2n codewords have the same length N2i-1 = N2i = (KI/2n + RI) for i = 1 to n, otherwise
the odd numbered codewords are equal and are one byte longer than the even numbered codewords, i.e. N2i-1 =(KI + n)/2n + RI bytes, and N2i = (KI – n)/2n + RI bytes for i = 1 to n. For the FEC output data frame, NI =

∑ N,
n

i =1

i

with NI < 512n - 1 bytes.
The convolutional interleaver requires all codewords to have the same odd length. To achieve the odd codeword length,
insertion of dummy (not transmitted) bytes may be required. For S = 1/2n, the dummy byte addition to the odd
numbered and/or even numbered codewords at the input of the interleaver shall be as in Table Q.4.

- 223 -

Table Q.4/G.992.1 –Dummy byte insertion at interleaver input for S = 1/2n
N2i-1
Odd
Even
Odd
Even

N2i
Odd
Even
Even
Odd

Dummy Byte Insertion Action
No action
Add one dummy byte at the beginning of all codewords
Add one dummy byte at the beginning of each even numbered codeword
Add one dummy byte at the beginning of each odd numbered codeword and two dummy bytes
at the beginning of each even numbered codeword [the de-interleaver shall insert one dummy
byte into the de-interleaver matrix on the first byte and the (D + 1)th byte of the corresponding
codeword to make the addressing work properly]

Q.5

ATU-R Functional Characteristics (pertains to clause 8)

Q.5.1

Framing (pertains to 8.4)

Q.5.1.1

Superframe structure (replaces 8.4.1.1)

The superframe structure of ATU-R transmitter is identical to that of ATU-C transmitter, as specified in Q.4.3.1.
Q.5.1.2

Hyperframe structure (replaces 8.4.1.3)

The hyperframe structure of ATU-R transmitter is functionally similar to that of ATU-C transmitter, except that theinverse synch symbol is used in the 1st superframe (SPF#0) (see Figure Q.16). The hyperframe is composed of 345
DMT symbols, numbered from 0 to 344. Each symbol is under FEXTC or NEXTC duration (see Q.5.3), and thefollowing numerical formula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-R
transmitter (see Figure Q.17).
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbol
then NEXTC symbol

128 DMT symbols are allocated in the FEXTC duration, and 217 DMT symbols are allocated in the NEXTC duration.
The symbols are composed of:
FEXTC symbol:
Number of symbol using Bitmap-FC
Number of synch symbol
Number of inverse synch symbol
NEXTC symbol:
Number of symbol using Bitmap-NC
Number of synch symbol

= 126
=1
=1
= 214
=3

During FEXT Bitmapping mode, the ATU-R shall not transmit any signal.

- 224 -

5 Superframe (= 340 frames)(point B)

1 Superframe = 68 frames (17 ms)

1 frame = 250 µs

Rate-Converter(point U-R, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#6

TC#33

TTRR
ATU-R
Crosstalk

NEXT

NEXT

FEXT
Hyperframe = 345 symbols (85 ms)

FEXT

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol N N N N N F F F F N N N

SPF#2

SPF#1
N F F I F N

S

S

SPF#3

SPF#4
S

S
T1532870-99

Sliding window

FEXTC duration

1 symbol = 246 µs
I

Inverse synch symbol

S

NEXTC Synch symbol

F

Symbol using Bitmap-FC (FEXTC duration bitmap)

N

Symbol using Bitmap-NC (NEXTC duration bitmap)

S

FEXTC Synch symbol

Figure Q.16/G.992.1 – Hyperframe structure for upstream- 225 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

ISS

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

101

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

SS

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

17

173

174

175

176

177

178

179

180

181

172
182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

SS

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

244

245

246

247

248

249

250

251

252

253

24

243

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

SS

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

SS

ISS Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol SS NEXTR synch symbol
NEXTR data symbol

T1535340-00

Figure Q.17/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Upstream

Q.5.1.3

Subframe structure (replaces 8.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table Q.5. The 34 subframes forma hyperframe.

- 226 -

Table Q.5/G.992.1 – Subframe (upstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

Q.5.2

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Inverse Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Synch Symbol#344 is Synch Symbol

Dual Bitmapping and rate conversion (replaces 8.15)

The function of the rate converter (see Q.5.2.2), tone ordering (see Q.5.4), constellation encoding, and gain scaling shalluse one of two bitmaps stored in the ATU. This method is called the dual bitmap.
Q.5.2.1

Dual Bitmap (new)The Dual Bitmap switching shall be the same as for the downstream data, specified in Q.4.4.1. The number of bits andthe relative gains to be used for every tone are calculated in the bit loading algorithm during the initialization sequence,and transmitted in C-B&G.
Q.5.2.2
Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FC, Bitmap-NC and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amounts of fast and interleaved data in Bitmap-FC and Bitmap-NC shall be calculated in thefollowing formulae:
If tCf ≤ nCmax:- 227 -

nCf = tCf
nCi = nC − nCf
f Cf = tCf
f Ci = f C − f Cf
If tCf > nCmax:

nCf = nC max

nCi = 0⎧⎡ tCf × 10 − nCf × 6 ⎤⎪ f Cf 4 = ⎢
⎥
4
⎪
⎢
⎥
f Cf = ⎨⎡ tCf ×10 − nCf × 7 ⎤⎪⎥⎪ f Cf 3 = ⎢3⎢⎥⎩⎧ f Ci 4 = f C − f C 4
f Ci = ⎨⎩ f Ci 3 = f C − f Cf 3
Where:
tCf
tCi
fCf and nCf
fCf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of fast bits in Bitmap-FC if the subframe (see Q.5.1.3) contains 3 Bitmap-FC except
for synch symbols.
fCf4
is the number of fast bits in Bitmap-FC if the subframe contains 4 Bitmap-FC except for synch
symbols.
fCi and nCi
are the numbers of interleaved bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of total bits in Bitmap-NC, which is specified in the B&G tables.
nC
During FEXT Bitmap mode, nCf and nCi are zero.

To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tCf ≤ nCmax:

dummyCf = 0

dummyCi = ( f Ci × 126 + nCi × 214) − tCi × 340
If tCf > nCmax:()
dummyCf 3 = ( f Cf × 3 + nCf × 7 ) − tCf ×10

dummyCf 4 = f Cf × 4 + nCf × 6 − tCf ×10

dummyCi = ( f Ci 4 × 96 + f Ci 3 × 30) − tCi × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FC constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:
dummySCf = fCf3 – fCf4

- 228 -

The receiver shall determine Bitmap-FC and Bitmap-NC so that dummyCi is less than 126, dummyCf4 is less than 4 anddummyCf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.
Q.5.3

FEXT Bitmapping (replaces 8.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (Q.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures Q.10 and Q.16).
Annex Q-EU does not support the FEXT Bitmapping mode.
Q.5.4

Tone Ordering (pertains to 8.7)

The tone ordering algorithm shall be the same as for the downstream data, specified in Q.4.4.
For Bitmap-FC, the "tone-ordered" encoding shall first assign fCf bits from the rate converter (see Q.5.2.2) to the tones
with the smallest number of bits assigned to them, and the remaining fCi bits to the remaining tones. For Bitmap-NC, it
shall first assign nCf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nCi bits to the remaining tones. Two ordered bit tables for Bitmap-FC and Bitmap-NC shall be prepared.
Q.5.5
Q.5.5.1

Modulation (pertains to 8.11)
Inverse synchronization symbol (replaces 8.11.4)

Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phase reversal of Synchronization
symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
Q.5.5.2

Gain scaling in synchronization symbol (new)At initialization time, the sync symbol reference transmit PSD level shall be set at the nominal PSD level+10log(gsync2) dBm/Hz, with gsync2 defined as the average gi2 value over the used (i.e. bi > 0) subcarriers in theNEXT or FEXT bitmap, whichever results in the highest average gain. The sync symbol reference transmit PSD shallnot be updated with used subcarrier gain changes during SHOWTIME.
I.5.5.3

Nyquist frequency (supplements 8.11.1.2)

The upstream Nyquist frequency for Annex Q-EU shall be at subcarrier NSCus (f = 4.3125*NSCus kHz).
I.5.5.4

Modulation by the inverse discrete Fourier transform (supplements 8.11.2)

For Annex Q-EU, see A.2.1.
I.5.5.5

Synchronization symbol (supplements 8.11.3)

For Annex Q-EU, see A.2.2.

Q.5.6

ATU-R Upstream Transmit Spectral Mask (replaces 8.14)

The upstream PSD masks of Annex Q-EU are defined with absolute peak values in Figure Q.18. The low frequency
stop band is defined for frequencies below 25.875 kHz; the high frequency stop band is defined at frequencies greaterthan f1 kHz (tone n1). The in-band region of these PSD masks is the frequency band from 25.875 kHz to f1 kHz.
ATU-x may optionally support upstream masks EU-36 to EU-64 specified in Figure Q.18
NOTE: The value of MAXNOMATPus may be limited by regional regulations.

- 229 -

PSD indBm/HzPEAKPSD(PEAKPSD+92.5)/2.69
dB/octave–72 dB/octave–100 dBm/Hz peak
–15 dB/octave–97.5
15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 1411 kHz–92.5 peak
PSD_int dBm/Hz–110 dBm/Hz–112 dBm/Hz

0425.875

f1

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < f1
f1< f < f_int
f_int < f < 686
f > 686
Frequency (kHz)04
425.875f1
f_int
686 – 12000

f_int

686

1411
1630 5275

Equation for line (dBm/Hz)-97.5-92.5+(PEAKPSD+92.5)* log2(f/4)/log2(25.875/4)
PEAKPSDPEAKPSD-72*log2(f/f1)
PSD_int-15*log2(f/f_int)-100
PSD level (dBm/Hz)
-97.5
-97.5
-92.5
PEAKPSDPEAKPSD
PSD_int-100

Measurement BW
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz

Additionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
1411
1630
5275
12000

Frequency
12000 in kHz

PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

NSCus is a function of the upstream mask parameters, which are defined as follows:- 230 -

Parameters in FEXT bitmap for mode 1, both bitmaps for mode 2 (see §Q.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64
EU-68
EU-72
EU-76
EU-80
EU-84
EU-88

NSCus

32
64
64
64
64
64
64
64
64
128
128
128
128
128
128

Template
Nominal PSD
P0 (dBm/Hz)

-38.0
-38.5
-39.0
-39.4
-39.8
-40.1
-40.4
-40.7
-41.0
-41.8
-42.1
-42.3
-42.6
-42.8
-43.0

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.0
-35.5
-35.9
-36.3
-36.6
-36.9
-37.2
-37.5
-38.3
-38.6
-38.8
-39.1
-39.3
-39.5

138.00155.25172.50189.75207.00224.25241.50258.75276.00293.25
310.50327.75345.00362.25379.50242.92274.03305.06336.33367.54399.07430.58462.04493.45522.12553.24584.89615.89647.47679.02

-93.2
-94.0
-94.7
-95.4
-95.9
-96.5
-97.0
-97.4
-97.9
-98.2
-98.6
-99.0
-99.3
-99.6
-99.9

When EU-68 or beyond is used, only mode 2 shall be used.

Mask definition for EU-92 to EU-112:
The same mask is used for both bitmaps (mode 2 only) and is defined in Figure Q.x1 and Table Q.x2.

Frequency (kHz)04
4
1025.875
f1
f_int
5275
12000

PSD level (dBm/Hz)
-97.5
-97.5
-92.5
interpolated
Inband_peak_PSD
Inband_peak_PSD
-100
-100
-100

- 231 -

Measurement BW
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHzFigure C.x1: Mask definition for EU-92 to EU-112

Designat
o
r
EU-92
EU-96
EU-100EU-104
EU-108
EU-112

Template
NominalPSD P0(dBm/Hz)
-43.2
-43.4
-43.7
-44.0
-44.5
-45.2

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5

InbandPeak PSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)

-39.7
-39.9
-40.2
-40.5
-41.0
-41.7

396.75414.00431.25448.50465.75483.00708.97738.37766.92795.30821.92846.64

Table C.x2: Parameters for EU-92 to EU-112

Parameters in NEXT bitmap for mode 1 (see §Q.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

Template
NominalPSD P0(dBm/Hz)

32
64
64
64
64
64
64
64
64

-38.0
-38.7
-39.9
-40.7
-41.4
-41.8
-42.1
-42.3
-42.3

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

-34.5
-35.2
-36.4
-37.2
-37.9
-38.3
-38.6
-38.8
-38.8

138.00155.25172.50189.75207.00224.25241.50258.75276.00Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)242.92273.47302.26331.87361.55392.16423.12454.51486.91

-93.2
-94.0
-94.7
-95.3
-95.8
-96.4
-96.9
-97.3
-97.8

NOTE 1 – All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
NOTE 2 – The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The breakpoints
in the tables shall be connected by linear straight lines on a dB/log(f) plot.
NOTE 3 – MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint with frequency fi
is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next specified breakpoint.
NOTE 4 – The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
NOTE 5 – The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued the21.5 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that this might impact
V.90 performance, and so the floor was extended to 4 kHz.
NOTE 6 – All PSD and power measurements shall be made at the U-R interface (see Figures Q.3 & Q.4).
Figure Q.18: Upstream Channel PSD Masks

Q.5.7

Forward error correction (supplements 8.6)

The minimum FEC coding capabilities (Table 8-3) for an ATU-R shall include the following interleave depths for the- 232 -

interleaved buffer:
D = 1, 2, 4, 8, and 16
Q.5.8

Cyclic prefix (supplements 8.12)

For Annex Q-EU, see A.2.3.

Q.6

EOC Operation and Maintenance (pertains to clause 9)

Q.6.1

ADSL line related primitives (supplements 9.3.1)

Q.6.1.1

ADSL line related near-end defects (supplements 9.3.1.3)

Two near-end defects are further defined:••

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.
Severely errored frame (SEF): A SEF defect occurs when the content of two consecutively received ADSL
synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R, does notcorrelate with the expected content over a subset of the tones. An SEF defect terminates when the content of twoconsecutively received ADSL synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR
duration at ATU-R, correlate with the expected contents over the same subset. The correlation method, theselected subset of tones, and the threshold for declaring these defect conditions are implementation discretionary.

Q.6.1.2

ADSL line related far-end defects (supplements 9.3.1.4)

Loss-of-signal is further defined:•

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.

Q.6.2

Test Parameters (supplements 9.5)

Q.6.2.1

Near-end test parameters (supplements 9.5.1)

The near-end primitives are further defined:••

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio (SNR) margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.

Q.6.2.2

Far-end test parameters (supplements 9.5.2)

The far-end primitives are further defined:
•
•

Q.6.3

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio SNR margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.
Data registers in the ATU-R (supplements 9.2.4)

For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).

- 233 -

Q.7

Initialization (pertains to clause 10)

Q.7.1

Initialization with Hyperframe (replaces 10.1.5)

The exchange of messages between ATU-C and ATU-R should be performed in FEXTC and FEXTR. The DMT
symbol has two symbol rates: one is 4.3125 kbaud for the symbol without a cyclic prefix, and the other is 4 x 69/68
kbaud for the symbol with a cyclic prefix. 32 times of the TTR has the same period as 345 times of the 4.3125 kbaud,
and 34 times of the TTR is the same as 345 times of 4 x 69/68 kHz.
During FEXT Bitmap mode, the ATU-R shall not transmit any signal during the NEXTC symbols duration and the
ATU-C shall transmit only the pilot tone as the NEXTR signal except:• C-PILOT1 (C-PILOT1A) which is accompanied by a signal to allow the ATU-C to indicate the phase of TTRC
to the ATU-R (see Q.7.4.1);• C-QUIETn where no signal is transmitted.
The ATU-C begins transmitting C-PILOT1 at the beginning of the hyperframe without cyclic prefix. The ATU-C
informs the phase of the TTRC to ATU-R during C-PILOT1. The ATU-R begins transmitting R-REVERB1 at the
beginning of the hyperframe without cyclic prefix. The ATU-R performs the training of any receiver equalizer using
this phase information of the TTRR generated from received TTRC.
From C-PILOT1 to C-SEGUE1, the following numerical formula gives the information which duration Ndmt-th DMT
symbol belongs to at ATU-R (see Figure Q.19).
For Ndmt = 0, 1, …344
S = 256 x Ndmt mod 2760
if { (S + 255 < a) or (S > a + b) }else
where a = 1243, b = 1461

then FEXTR symbols
then NEXTR symbols

In order to enter C-RATES1 at the beginning of the hyperframe with cyclic prefix, the number of symbols from
C-PILOT1 to C-SEGUE1 shall be a multiple of 345 DMT symbols.
From R-REVERB1 to R-SEGUE1, the following numerical formula gives the information which duration Ndmt-th
symbol belongs to at ATU-C (see Figure Q.20).
For Ndmt = 0, 1, …, 344,
S = 256 x Ndmt mod 2760
if { (S > a) and (S + 255 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols

From C-RATES1 to C-SEGUE3, the number of symbols is a multiple of 345 DMT symbols. The following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-C transmits the message data in
FEXTR symbols (see Figure Q.11).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760
if { (S + 271 ≥ a) and (S ≤ a + b) }else
where a = 1243, b = 1461

then NEXTR symbols
then FEXTR symbols

The ATU-R enters R-REVERB3 at the beginning of the hyperframe with cyclic prefix, which is extracted fromreceived signal. From R-REVERB3 to R-SEGUE5, the number of symbols is a multiple of 345 DMT symbols. The- 234 -

following numerical formula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-R transmits
the message data in FEXTC symbols (see Figure Q.17).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols- 235 -

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14

0

1

2

3

4

5

6

7

8

9

10

11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
107
97
98
99
100
101
102
103
104
105
106
108
109
110
111
112
113
114
115
116
117 118
119
120
121
122
123
124
125
126
127
128
129 130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
161
151
152
153
154
155
156
157
158
159
160

162
163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181
182
184
185
186
187
188
189
190
191
192
193
17 183
204
195
196
197
198
199
200
201
202
203
18 194
205
206
207
208
209
210
211
212
213
214 215
19
20
216
217
218
219
220
221
222
223
224
225
228
229
230
231
232
233
234
235
236
21 226 227
238
239
240
241
242
243
244
245
246
247
22 237
258
248
249
250
251
252
253
254
255
256
257
23
24
259
260
261
262
263
264
265
266
267
268 269
15
16

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311 312
313
314
315
316
317
318
319
320
321
322
29
323
324
325
326
327
328
329
330
331
332
333
30
335
336
337
338
339
340
341
342
343
344
31 334
25
26
27
28

280

FEXTR symbol

T1535350-00

NEXTR symbol

Figure Q.19/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Downstream- 236 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

10

1

11

12

13

14

15

16

17

18

19

20

2

22

23

24

25

26

27

28

29

30

31

3 32
4 43
5

33

34

44

54

35

45

55

6

65

7 75
8 86

76

56

66

57

77
98

99

108

109

110

23
24

82

92

102

112

62

72

63

73

83

93

103

113

64

74

84

94

104

114

53

85

95

105

115

96
107

106

116

117

118

121

122

123

124

125

126

127

128

132

133

134

135

136

137

138

139

142

143

153

163

144

154

164

145

155

165

146

156

166

147

157

167

148

158

168

149

159

169

150
161

160

170

171

172

174

175

176

177

178

179

180

181

182

184

185

186

187

188

189

190

191

192

193
204

195

205

196

206

216

21 22622 239

81

91

101

111

61

71

42

52

173

17 18318 194
19
20

80

41

51

131
152

162

15
16

60

70

90

40

50

120

141

140
151

59

79
100

39

49

69

89

97

14

58

78

9

38

48

68

88

10

13

37

47

67

87

119
11
12 129 130

36

46

21

197

207

217

198

208

218

199

209

219

200

210

220

201

211

221

202

212

222

203

213

223

215

214

224

225

227

228

229

230

231

232

233

234

235

236

238

239

240

241

242

243

244

245

246

247
258

248

249

259

250

260

251

261

252

262

253

263

254

264

255

265

256

266

257

267

268

269

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
26 280
292
293
294
295
296
297
298
299
300
301
27 291
28
302
303
304
305
306
307
308
309
310
311
312
25

29
30 32331 334

313

314

324
335

315

325
336

316

326
337

317

327

318

328

338

339

319

329
340

320

330
341

321

331
342

322

332
343

333
344
T1535360-00

FEXTC symbol
NEXTC symbol

Figure Q.20/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Upstream

Q.7.2

Handshake – Non-standard information block (new)This section defines the format of the G.994.1 non-standard information block to support Annex Q-EU, and tabulates
the parameters used by Annex Q-EU. The use of these parameters is described in §Q.7.3 and §Q.7.4.

Q.7.2.1 Non-standard information block format (new)Figure Q.21 defines the format of the non-standard information block.

- 237 -

8

7

6

5

4

3

2

1

Non-standard information length = M + 6(1 octet)
T.35 country code
(2 octets – see Note 1)
Provider code (vendor identification)(4 octets – see Note 2)
Vendor-specific information(M octets – Note 3)
NOTE 1 – The value of this field shall be B5 00, the country code for USA
NOTE 2 – The value of this field shall be 43 45 4E 54, ASCII “CENT” for Centillium
Communications
NOTE 3 – These octets are defined in §Q.7.2.2. Formatting of these octets shall comply with theparsing rules defined in G.994.1 §9.2.1 to §9.2.3

Figure Q.21 – Non-standard information block format

Q.7.2.2 Non-standard information block parameters (new)The G.994.1 non-standard parameters for Annex Q-EU are listed in Tables Q.6 to Q.7.2.1.2.5 below.
In order to minimize message length, the parameters for additional inband spectral shaping (Spar(2) octet and its related
Npar(3) octets) shall only be included in MP or MS messages, and shall not be included in CLR or CL messages. All
Annex Q-EU modems shall support additional inband spectral shaping.
Note - This deviates from the rules specified in G.994.1 for standard information fields, where it isstated in §9.6:“Once a Transaction C (see 10.1) has been completed, any subsequent MS message
within the same G.994.1 session shall only contain those octets of the identification (I)and standard information (S) fields, and those blocks of non-standard information (NS)that were contained in both the CLR and CL messages of the previous Transaction C”.

Table Q.6 – Non-standard information field – NPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Reserved for future use

x

x

x

x

x

x

1

x

Reserved for future use

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet- 238 -

NPar(1)sTable Q.7 – Non-standard information field – SPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

G.992.1 Annex Q (and Annex Q-EU)

x

x

x

x

x

x

1

x

G.992.1 Annex I-EU

x

x

x

x

x

1

x

x

G.992.1 Annex C-EU

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet

SPar(1)sTable Q.7.1 – Non-standard information field – G.992.1 Annex Q NPar(2) coding – Octet 1
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

nC-PILOT1 = 64

x

x

x

x

x

x

1

x

nC-PILOT1 = 128

x

x

x

x

x

1

x

x

nC-PILOT1 = 256

x

x

x

x

1

x

x

x

Amateur radio notch – 1.8 MHz band

x

x

x

1

x

x

x

x

Amateur radio notch – 3.5 MHz band

G.992.1 Annex Q NPar(2)s – Octet 1

x

x

1

x

x

x

x

x

nC-PILOT1 = 96

x

x

0

0

0

0

0

0

No parameters in this octet

Since A48 is the only TTR indication signal specified for Annex Q-EU, there is no need to include it in G.994.1.

Table Q.7.1.1 – Non-standard information field – G.992.1 Annex Q NPar(2) coding – Octet 2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

R-ACK1

x

x

x

x

x

x

1

x

R-ACK2

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

G.997.1 – Clear EOC OAM

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex Q NPar(2)s – Octet 2

Since Annex Q-EU only supports ATM transport, STM and ATM parameters are not specified. Since FBM mode is
not supported, the DBM bit is also not specified.

- 239 -

Table Q.7.2 – Non-standard information field – G.992.1 Annex Q SPar(2) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Additional inband spectral shaping

x

x

x

x

x

x

1

x

Extended upstream

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex Q SPar(2)s

Table Q.7.2.1 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 1
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 1x

x

NOMINAL_PSD_lowband (bits 8 & 7)x

Reserved for future use

Table Q.7.2.1.1 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 2
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 2

x

x

x

x

x

x

x

x

NOMINAL_PSD_lowband (bits 6 to 1)

Table Q.7.2.1.2 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 3
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 3x

x

PSD level at 1622 kHz (bits 8 & 7)x

Reserved for future use- 240 -

Table Q.7.2.1.3 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 4
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 4

x

x

x

x

x

x

x

x

PSD level at 1622 kHz (bits 6 to 1)

Table Q.7.2.1.4 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 5
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 5x

x

PSD level at 3750 kHz (bits 8 & 7)x

Reserved for future use

Table Q.7.2.1.5 – Non-standard information field – G.992.1 Annex Q Additional inband
spectral shaping Npar(3) coding
Octet 6
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Additional inband spectral shaping
Npar(3)s Octet 6

x

x

x

x

x

x

x

x

PSD level at 3750 kHz (bits 6 to 1)

Table Q.7.2.2 – Non-standard information field – G.992.1 Annex Q Extended upstream
NPar(3) coding Octet 1
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Extended upstream NPar(3)s Octet
1

x

x

x

x

x

x

x

1

Mode 1 upstream mask

x

x

x

x

x

x

1

x

Mode 2 upstream mask

x

x

x

x

x

1

x

x

Optional upstream masks for non-overlapped spectrum

x

x

x

x

1

x

x

x

EU-64

x

x

x

1

x

x

x

x

EU-32

x

x

1

x

x

x

x

x

EU-36

x

x

0

0

0

0

0

0

No parameters in this octet- 241 -

Table Q.7.2.2.1 – Non-standard information field – G.992.1 Annex Q Extended upstream
NPar(3) coding Octet 2
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Extended upstream NPar(3)s Octet
2

x

x

x

x

x

x

x

1

EU-40

x

x

x

x

x

x

1

x

EU-44

x

x

x

x

x

1

x

x

EU-48

x

x

x

x

1

x

x

x

EU-52

x

x

x

1

x

x

x

x

EU-56

x

x

1

x

x

x

x

x

EU-60

x

x

0

0

0

0

0

0

No parameters in this octet

Table Q.7.2.2.2 – Non-standard information field – G.992.1 Annex Q Extended upstream
NPar(3) coding Octet 3
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Extended upstream NPar(3)s Octet
3

x

x

x

x

x

x

x

1

EU-68

x

x

x

x

x

x

1

x

EU-72

x

x

x

x

x

1

x

x

EU-76

x

x

x

x

1

x

x

x

EU-80

x

x

x

1

x

x

x

x

EU-84

x

x

1

x

x

x

x

x

EU-88

x

x

0

0

0

0

0

0

No parameters in this octet

Table Q.7.2.2.3 – Non-standard information field – G.992.1 Annex Q Extended upstream
NPar(3) coding Octet 4
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex Q Extended upstream NPar(3)s Octet
4

x

x

x

x

x

x

x

1

EU-92

x

x

x

x

x

x

1

x

EU-96

x

x

x

x

x

1

x

x

EU-100

x

x

x

x

1

x

x

x

EU-104

x

x

x

1

x

x

x

x

EU-108

x

x

1

x

x

x

x

x

EU-112

x

x

0

0

0

0

0

0

No parameters in this octet- 242 -

Q.7.3

Handshake – Parameter definitions (supplements 10.2)

Q.7.3.1 Handshake – ATU-C (supplements 10.2)
Q.7.3.1.1

CL messages (supplements 10.2.1)

See Table Q.8.

Table Q.8/G.992.1 – ATU-C CL message NPar(2) bit definitions for Annex Q
NSF parameter

Definition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-C is configured to support G.992.1
Annex Q, and possibly Annex Q-EU.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 96.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission of pilot
tone on subcarrier 256.
If set to ONE, this Npar(2) bit indicates that the ATU-C is configured to reduce its transmit
power between 1.81 and 2.0 MHz to ≤ –80 dBm.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band

Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped
spectrumIf set to ONE, this Npar(2) bit indicates that the ATU-C is configured to reduce its transmit
power between 3.5 and 3.8 MHz to ≤ –80 dBm.

If set to ONE, this Spar(2) bit indicates that the ATU-C is configured to support extended
upstream.
If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-C supports. For non-overlapped spectrum, extended upstream
masks are associated with downstream masks according to Figure Q.13. For overlapped
spectrum, any EU-xx may be used with the overlapped downstream spectrum specified in§Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support the optional
upstream masks when using non-overlapped spectrum downstream.

- 243 -

Q.7.3.1.2

MS messages (supplements 10.2.2)

See Table Q.9.

Table Q.9/G.992.1 – ATU-C MS message NPar(2) bit definitions for Annex Q
NSF bitG.992.1 Annex Q
nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_
lowband
PSD level at 1622
kHz

PSD level at 3750
kHz

Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped
spectrum

Definition

If set to ONE, this Spar(1) bit indicates that the ATU-C is selecting G.992.1 Annex Q, andpossibly Annex Q-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 256 (Note 1).
If set to ONE, this Npar(2) bit indicates that the ATU-C shall reduce its transmit power
between 1.81 and 2.0 MHz to ≤ –80 dBm.
If set to ONE, this Npar(2) bit indicates that the ATU-C shall reduce its transmit power
between 3.5 and 3.8 MHz to ≤ –80 dBm.
If set to ONE, this Spar(2) bit indicates that the ATU-C shall apply additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply in the passband below 1104 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply at 1622 kHz. It is coded in steps of 0.125dB relative to NOMINAL_PSD_lowband(–40dBm/Hz). For example, 00000000 means –40 dBm/Hz; 00001101 means -41.625
dBm/Hz. The PSD level shall be linearly interpolated in dBs between the
REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply at 3750 kHz. It is coded in steps of 0.125dB relative to NOMINAL_PSD_lowband(–40dBm/Hz). For example, 00000000 means –40 dBm/Hz; 00001101 means -41.625
dBm/Hz. The PSD level shall be linearly interpolated in dBs between the PSD level at 1622
kHz and the PSD level at 3750 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-C is selecting extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-C is selecting upstream PSD mask USxx. For non-overlapped spectrum, extended upstream masks are associated with downstream
masks according to Figure Q.13. For overlapped spectrum, any EU-xx may be used with theoverlapped downstream spectrum specified in §Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 1(different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 2(same mask during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

- 244 -

Note 1: One and only one pilot tone bit shall be set in an MS message.
Note 2: One and only one upstream mask mode bit shall be set in an MS message.

Q.7.3.2 Handshake – ATU-R (supplements 10.3)
Q.7.3.2.1

CLR messages (supplements 10.3.1)

See Table Q.10.

Table Q.10/G.992.1 – ATU-R CLR message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-R is configured to support G.992.1
Annex Q, and possibly Annex Q-EU.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 96.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 256.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports the 1.8 MHz
Amateur radio band notch.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports the 3.5 MHz
Amateur radio band notch.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Amateur radio notch– 3.5 MHz band

Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum

If set to ONE, this Spar(2) bit indicates that the ATU-R is configured to support extended
upstream.
If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-R supports. For non-overlapped spectrum, extended upstream
masks are associated with downstream masks according to Figure Q.13. For overlapped
spectrum, any EU-xx may be used with the overlapped downstream spectrum specified in§Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support the optional
upstream masks when using non-overlapped spectrum downstream.

- 245 -

Q.7.3.2.2

MS messages (supplements 10.3.2)

Table Q.11.

Table Q.11/G.992.1 – ATU-R MS message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-R is selecting G.992.1 Annex Q, andpossibly Annex Q-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_
lowband
PSD level at 1622
kHz

PSD level at 3750
kHz

Extended
upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped
spectrum

This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 3750 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 3750 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-R is selecting upstream PSD mask USxx. For non-overlapped spectrum, extended upstream masks are associated with downstream
masks according to Figure Q.13. For overlapped spectrum, any EU-xx may be used with theoverlapped downstream spectrum specified in §Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode 1(different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode 2(same mask during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

- 246 -

Note 1: One and only one pilot tone bit shall be set in an MS message.
Note 2: One and only one upstream mask mode bit shall be set in an MS message.

Q.7.3.2.3

MP messages (new)Table Q.12.
Table Q.12/G.992.1 – ATU-R MP message NPar(2) bit definitions for Annex Q
NSF bitDefinition

G.992.1 Annex Q

If set to ONE, this Spar(1) bit indicates that the ATU-R is proposing G.992.1 Annex Q, andpossibly Annex Q-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is proposing the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio
notch – 1.8 MHz
band
Amateur radio
notch – 3.5 MHz
band
Additional inband
spectral shaping
REDUCED_PSD_lowbandPSD level at 1622
kHz

PSD level at 3750
kHz

Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped
spectrum

This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 3750 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs between
the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 3750 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs between
the PSD level at 1622 kHz and the PSD level at 3750 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-R is proposing upstream PSD mask USxx. For non-overlapped spectrum, extended upstream masks are associated with downstream
masks according to Figure Q.13. For overlapped spectrum, any EU-xx may be used with theoverlapped downstream spectrum specified in §Q.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode 1(different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode 2(same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing one of the optional
upstream masks when using non-overlapped spectrum downstream.

- 247 -

Note 1: More than one pilot tone bit may be set in an MP message.

Q.7.4

Transceiver Training – ATU-C (supplements 10.4)

During transceiver training from C-REVERB1 to C-SEGUE1 except C-PILOTn and C-QUIETn, the ATU-C shalltransmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), and shall not transmit
the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state isdefined as Figure Q.26.
Q.7.4.1

C-PILOT1 (supplements 10.4.2)

The ATU-C shall start the NSWF (sliding window frame) counter from 0 immediately after entering C-PILOT1, andincrement the NSWF counter modulo 345 after transmission of each DMT symbol. According to the sliding windowfunction and this counter, the ATU-C decides to transmit all of the subsequent symbols in either FEXTR or NEXTR
symbols (for example, see Figures Q.11, Q.19 and Q.24).
C-PILOT1 has two signals.
The first signal is the pilot tone, a single frequency sinusoid at fC-PILOT1 defined as:⎧ 0, k ≠ nC − PILOT 1 , 0 ≤ k ≤ NSCds
Xk = ⎨
AC − PILOT 1 , k = nC − PILOT 1⎩
The frequency of the pilot tone shall be selected from one of the following choices during G.994.1 as:
12. fC-PILOT1 = 276 kHz (nC-PILOT1 = 64).
13. fC-PILOT1 = 414 kHz (nC-PILOT1 = 96).
14. fC-PILOT1 = 552 kHz (nC-PILOT1 = 128).
15. fC-PILOT1 = 1104 kHz (nC-PILOT1 = 256).
Transmitters that support Annex Q-EU shall support all of these pilot tones.
The second signal is the TTR indication signal used to transmit NEXTR/FEXTR information. The ATU-R can detect
the phase information of the TTRC from this signal. The TTR indication signal shall be selected during G.994.1 as:
A48 signal –the constellation encoding of the 48th carrier with 2-bit constellation as follows:(+ , +) to indicate a FEXTR symbol;(+ , –) to indicate a NEXTR symbol.
Q.7.4.2

C-PILOT1A (supplements 10.4.3)

C-PILOT1A has two signals and it is the same transmitted signal as C-PILOT1 (C.7.4.1).
Q.7.4.3

C-REVERB3 (supplements 10.4.11)

In order to synchronize the first symbol of C-RATES1 with the beginning of the hyperframe and to inform the enteringtiming of C-RATES1 to the ATU-R, the first symbol of C-SEGUE1 shall be transmitted inside of the FEXTR duration
as shown in Figure Q.22. Therefore, the duration of C-REVERB3 is 3628 DMT symbols.

- 248 -

TTRC
20 symbols
C-SEGUE1

C-REVERB3

C-RATES1

the time of the detection
C-SEGUE1

R-REVERB3
T1532880-99

Figure Q.22/G.992.1 – Timing diagram from C-SEGUE1 to C-RATES1

Q.7.4.4 C-REVERB1 (replaces 10.4.5)
C-REVERB1 is a signal that allows the ATU-C and ATU-R receiver to adjust its automatic gain control (AGC) to an
appropriate level. The data pattern used in C-REVERB1 shall be the pseudo-random downstream sequence (PRD), dn
for n = 1 to 2*NSCds, defined in Q.4.7.5 and repeated here for convenience:dn = 1dn = dn-4 ⊕ dn-9

for n = 1 to 9
for n = 10 to 2*NSCds(10-1)The bits shall be used as follows: the first pair of bits (d1 and d2) is used for the DC and Nyquist subcarriers (the powerassigned to them is, of course, zero, so the bits are effectively ignored); then the first and second bits of subsequentpairs are used to define the Xi and Yi for i = 1 to NSCds-1 as defined in Table 7-13.
The period of PRD is only 511 bits, so dn+511 is equal to dn. The bits d1 to d9 shall be re-initialized for each symbol,
so each symbol of C-REVERB1 is identical.
The two bits that modulate the pilot carrier shall be overwritten by {0,0}: generating the {+,+} constellation.
The duration of C-REVERB1 is 512 (repeating) symbols without cyclic prefix.
Q.7.4.4.1

Power Cut-back (supplements 10.4.5.1)

For Annex Q-EU, see A.3.1.

Q.7.5

Transceiver Training – ATU-R (supplements 10.5)

During transceiver training from R-REVERB1 to R-SEGUE1 except R-QUIETn, the ATU-R shall transmit both
FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC
symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is defined as Figure Q.26.
Q.7.5.1

R-QUIET2 (supplements 10.5.1)

The ATU-R enters R-REVERB1 after it completes timing recovery and Hyperframe synchronization from
C-PILOT1/C-PILOT1A.
Q.7.5.2

R-REVERB1 (supplements 10.5.2)

The data pattern used in R-REVERB1 is the pseudo-random upstream sequence PRU defined in 8.11.3, repeated as- 249 -

necessary for the the selected NSCus:⎧d n = 1⎨⎩d n = d n − 5

for n = 1 to 6
⊕ d n −6 for n = 7 to 2 * NSCus(C.10-1)

The period of PRU is only 63 bits, so dn+63 is equal to dn.
The ATU-R shall start its NSWF counter immediately after entering R-REVERB1, and then increment the NSWF
counter with modulo 345 from 0 when it transmits each DMT symbol. The ATU-C and ATU-R shall have the samevalue since hyperframe alignment between the ATU-C and ATU-R shall be maintained. According to the sliding
window and this counter, the ATU-R decides to transmit all of the subsequent symbols in either the FEXTC or the
NEXTC symbol.
Q.7.5.3

R-QUIET3 (replaces 10.5.3)

The final symbol of R-QUIET3 accommodates the frame alignment of the transmitter to that of the receiver. It may be
shortened by any number of samples. The maximum duration of R-QUIET3 is 6145 DMT symbols.
Q.7.5.4

R-REVERB2 (supplements 10.5.5)

After ATU-R detects C-SEGUE1, the ATU-R enters R-SEGUE1. The maximum duration of R-REVERB2 is 3643
DMT symbols.
Q.7.6

Channel analysis (ATU-C) (supplements 10.6)

ATU-C shall transmit only FEXTR symbols, and shall not transmit the NEXTR symbols except the pilot tone from
C-RATES1 to C-CRC2. During C-MEDLEY, the ATU-C shall transmit both FEXTR and NEXTR symbols when
Bitmap-NR is enabled (Dual Bitmap mode). The ATU-C shall not transmit NEXTR symbols except the pilot tone,
when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state is defined in Figure Q.26.
Q.7.6.1

C-SEGUE1 (supplements 10.6.1)

The duration of C-SEGUE1 is 20 symbols in order that the first symbol of C-SEGUE1 shall be inside of the FEXTR
duration.
Q.7.6.2

C-MEDLEY (replaces 10.6.6)

C-MEDLEY is a wideband pseudo-random signal used for estimation at the ATU-R of the downstream SNR. The data
to be transmitted are derived from the pseudo-random sequence, PRDm defined as:
d n = 1 for n = 1 to 14 and d n = d n-5 ⊕ d n-11 ⊕ d n-12 ⊕ d n-14 for n> 14,
and modulated as defined in 10.4.5. In contrast to C-REVERB1, the cyclic prefix is used and the data sequence
continues from one symbol to the next (i.e. d1 to d14 are not re-initialized for each symbol). Because the sequence is oflength 214-1, and far fewer bits are used for each symbol, the subcarrier vector for C-MEDLEY changes from one
symbol period to the next. For non-overlapped spectrum, 2*(869-mm+1) bits are used each symbol, where mm is theminimum subcarrier specified for PSD mask DS-mm in Table Q.13. For overlapped spectrum, 2*864 bits are used eachsymbol. The pilot subcarrier is overwritten by the (+,+) signal constellation. The duration of C-MEDLEY is as shown in
Figure Q.26. Following C-MEDLEY the ATU-C shall enter the state C-REVERB4.
With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure Q.23. The ATU-C
transmits the signal in both of NEXTR and FEXTR symbols, and the ATU-R estimates two SNRs from the received
NEXTR and FEXTR symbols, respectively, as defined in Figure Q.24.
The following formula gives the information that received Ndmt-th DMT symbol belongs to:- 250 -

For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > d) }if { (S > b) and (S + 271 < c) }where a = 1243, b = 1403, c = 2613, d = 2704

then symbol for estimation of FEXTR SNR
then symbol for estimation of NEXTR SNR

When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbol. The
number of bits of NEXTR shall be no more than the number of bits of FEXTR.
At the transmitter, the PRDm sequence generator shall continue to be updated during NEXTR symbols when BitmapNR is disabled (FEXT Bitmap mode).

TTR
TCM-ISDN crosstalkat ATU-R receiver

TCM-ISDN crosstalkat ATU-C receiver

NEXT

NEXT

FEXT

FEXT

FEXT

NEXT

NEXT

NEXT

FEXT

FEXT
Estimation of
Signal-to-Noise ratio

C/R-MEDLEY (49152 symbols)

Bitmap for Downstream

Bitmap-NR

Bitmap-FR

Bitmap-FR

Bitmap-NR

Bitmap for Upstream

Bitmap-FC

Bitmap-NC

Bitmap-NC

Bitmap-FC
T1532890-99

Figure Q.23/G.992.1 – Estimation of periodic Signal-to-Noise Ratio- 251 -

TTRC
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

4
5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

101

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

137

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

17
18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

206

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

243

24

244

245

246

247

248

249

250

251

252

253

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

275

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

315

316

317

318

319

320

321

322

323

324

31

314

32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

Symbol for estimation of FEXTR S/N
Symbol for estimation of NEXTR S/N

Symbol not used for S/N estimation
T1535370-00

Figure Q.24/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Downstream

Q.7.6.3

C-RATES1 (supplements 10.6.2)

In order to support data rates greater than 32 Mbit/s, the BI field has 11 bits. The RRSI fields shall use the same
extended syntax as defined in Q.7.9.4 for C-RATES-RA.

- 252 -

For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7.6.4

C-MSG1 (supplements 10.6.4)

Table Q.13/G.992.1 – Assignment of 48 bits of C-MSG1
Suffix(ces) of mi (Note 1)
Parameter (Note 3)
47-44
Minimum required downstream SNR margin at initialization (Note 2)
43-18
Reserved for future use
17
Trellis coding option
16
Overlapped spectrum option (Note 4)
15
Unused (shall be set to "1")
14-12
Reserved for future use
11
NTR
10-9
Framing mode
8-6
Transmit PSD during initialization
5
Reserved
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – A positive number of dB; binary coded 0-15 dB.
NOTE 3 – All reserved bits shall be set to "0".
NOTE 4 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
Q.7.6.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.6.4.8)

The Ndownmax (transmit) capability shall be binary encoded onto {m4, ..., m0} (e.g. 100012 = 17). The maximum
number of bits for the upstream data, Nupmax, that the ATU-C receiver can support need not be signalled to the ATU-R;
it will be implicit in the bits and gains message, C-B&G, which is transmitted after channel analysis.
Q.7.7

Channel analysis (ATU-R) (supplements 10.7)

From R-RATES1 to R-CRC2, the ATU-R shall transmit only the FEXTC symbols and shall not transmit the NEXTC
symbols. In R-SEGUE2 and R-MEDLEY, the ATU-R shall transmit both FEXTC and NEXTC symbols when
Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC symbols when Bitmap-NC is disabled(FEXT Bitmap mode). The duration of each state is defined in Figure Q.26.
Q.7.8

R-SEGUE1 (supplements 10.7.1)

The maximum duration of R-SEGUE1 is 14 symbols (see Figure Q.22).
Q.7.8.1

R-REVERB3 (supplements 10.7.2)

The ATU-R shall start R-REVERB3 aligned with the beginning of a Hyperframe.
Q.7.8.2

R-SEGUE2 (supplements 10.7.3)

The duration of R-SEGUE2 is 13 symbols.
Q.7.8.3

R-MEDLEY (replaces 10.7.8)

R-MEDLEY is a wideband pseudo-random signal used for estimation of the upstream SNR at the ATU-C. The data to
be transmitted are derived from the pseudo-random sequence PRUm defined as:
d n = 1 for n = 1 to 23 and d n = d n-18 ⊕ d n-23 for n> 23.
In contrast to R-REVERB1, the cyclic prefix is used and the data sequence continues from one symbol to the next (i.e.

- 253 -

d1 to d23 are not re-initialized for each symbol). Because the sequence is of length 223-1, and 2*(nn-5) bits are used foreach symbol (where nn is the maximum subcarrier specified for PSD mask EU-nn in Table Q.18), the subcarrier vector
for R-MEDLEY changes from one symbol period to the next. Following R-MEDLEY the ATU-R enters signalling state
R-REVERB4. The duration of R-MEDLEY is as shown in Figure Q.26.
With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure Q.23. ATU-R shalltransmit the signal in both of NEXTC and FEXTC symbols, and ATU-C shall estimate two SNRs from the received
NEXTC and FEXTC symbols, respectively, as defined in Figure Q.25.
The following numerical formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > b) and (S + 271 < c) }if { (S + 271 < a) }where a = 1148, b = 1315, c = 2608

then symbol for estimation of FEXTC SNR
then symbol for estimation of NEXTC SNRWhen Bitmap-NC is disabled (FEXT Bitmap mode), the ATU-R shall not transmit NEXTC symbol. The number of bitsof NEXTC shall be no more than the number of bits of FEXTC.
At the transmitter, the PRUm sequence generator shall continue to be updated during NEXTC symbols when BitmapNC is disabled (FEXT Bitmap mode).

- 254 -

TTR R
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

101

10

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

11
12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

137

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

172

17

173

174

175

176

177

178

179

180

181

182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

206

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

243

24

244

245

246

247

248

249

250

251

252

253

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

275

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

T1535290-00

Symbol for estimation of FEXT C S/N

Symbol not used for S/N estimation

Symbol for estimation of NEXT C S/N

Figure Q.25/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Upstream- 255 -

Q.7.8.4

R-MSG1 (supplements 10.7.6)

Table Q.14/G.992.1 – Assignment of 48 bits of R-MSG1
Parameter (Note 2)
Suffix(ces) of mi (Note 1)
47-18
Reserved for future use

17
Trellis coding option
16
Overlapped spectrum option (Note 3)
15
Unused (shall be set to "1")14
Support of S = 1/2 mode (see Q.4.9) (Note 4)
13
Support of dual latency downstream
12
Support of dual latency upstream
11
Network Timing Reference
10, 9
Framing mode
8-5
Reserved for future use
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
NOTE 3 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
NOTE 4 – Since the S=1/2 mode is mandatory for Annex Q, a modem supporting Annex Q shall set this bit to binaryONE.

Q.7.8.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.7.6.6)

The Nupmax (transmit) capability is encoded onto {m4 , ..., m0} with a conventional binary representation (e.g.
100012 = 17).
Q.7.9

Exchange – ATU-C (supplements 10.8)

During C-RATESn, C-MSGn, C-B&G, and C-CRCn, the ATU-C shall transmit the FEXTR symbol. In the other signals,
the ATU-C shall transmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), andshall not transmit the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The
duration of each state is defined in Figure Q.27.

- 256 -

Q.7.9.1

C-MSG2 (supplements 10.8.9)

Replace Table 10-13 with Table Q.15.

Table Q.15/G.992.1 – Assignment of 32 bits of C-MSG2
Suffix(ces) of mi (Note 1)

Parameter (Note 2)

31-26

Estimated average loop attenuation

25-21

Reserved for future use

20-16

Performance margin with selected rate option

15-11

Reserved for future use

10-0

Total number of bits supported

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
For NSCus=32,
n1C-MSG2 = 43
n2C-MSG2 = 91
Otherwise,
n1C-MSG2 = 139
n2C-MSG2 = 187
Q.7.9.1.1

Total number of bits per symbol supported (replaces 10.8.9.3)

The ATU-C receiver shall also calculate the maximum number of bits per symbol that the upstream channel can support−7

with the performance margin defined in C-MSG-RA at an error rate of 10 .
The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTC and
NEXTC downstream channel performance [e.g. if the maximum numbers of bits that can be supported in FEXTC and
NEXTC symbols are 111 and 88 {Total number of bits per symbol supported} = (111 x 126 + 88 x 214)/340 = 96]. This
number is encoded into bits 10-0 using a conventional binary representation [e.g. if the maximum number of bits thatcan be supported is 96 (data rate = 384 kbit/s), {m10, ..., m0} = 000011111112].
NOTE – The number of symbols per hyperframe is 340. The number of FEXT symbols is 126. The number of NEXTsymbols is 214.
Q.7.9.1.2

Estimated average upstream loop attenuation (supplements 10.8.9.1)

For Annex Q-EU, see A.3.2.

Q.7.9.2

C-B&G (replaces 10.8.13)

C-B&G shall be used to transmit to the ATU-R the bits and gains information, Bitmap-FC {b1, g1, b2, g2, ... bNSCus-1,
gNSCus-1}, and Bitmap-NC {bNSCus+1, gNSCus+1, bNSCus+2, gNSCus+2, ..., b2*NSCus-1, g2*NSCus-1}, that are
to be used on the upstream carriers. bi of Bitmap-FC indicates the number of bits to be coded by ATU-R transmitter
onto the i th upstream carrier in FEXTC symbols; gi of Bitmap-FC indicates the scale factor, relative to the gain thatwas used for that carrier during the transmission of R-MEDLEY, that shall be applied to the i th upstream carrier in
FEXTC symbols. Similarly, bi of Bitmap-NC indicates the number of bits onto the (i – NSCus) th upstream carrier in- 257 -

NEXTC symbols; gi of Bitmap-NC indicates the scale factor that shall be applied to the (i – NSCus) th upstream carrierin NEXTC symbols.
Because no bits or energy will be transmitted at DC or one-half the sampling rate, b0, g0, bNSCus, gNSCus, b2*NSCus,
and g2*NSCus are all presumed to be zero and shall not be transmitted.
Each bi shall be represented as an unsigned 5-bit integer, with valid bis lying in the range of zero to Nupmax, themaximum number of bits that the ATU-R is prepared to modulate onto any subcarrier, which is communicated in
R-MSG1.
Each gi shall be represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of
the third most significant bit. For example, a gi with binary representation (most significant bit listed first)
001.010000002 would instruct the ATU-R to scale the constellation for carrier i, by a gain factor of 1.25, so that thepower in that carrier shall be 1.94 dB higher than it was during R-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
Let NSCu=128, except when EU-32 is used where NSCu=32. The C-B&G information shall be mapped in a32*(NSCu-1)-bit [4*(NSCu-1) byte] message m defined by:
m = {m32*(NSCu-1)-1, m32(NSCu-1)-2, …, m1, m0} = { g2*NSCu-1, b2*NSCu-1, …, gNSCu+1, bNSCu+1,
gNSCu-1, bNSCu-1, …, g1, b1},
(C.10-2)
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in
4*(NSCu-1) FEXTR symbols. When NSCu=32, including C_CRC5, the total length is 336 symbols while for
NSCu=128, the total length is 336+3*345=1371 symbols, using the transmission method as described in 10.8.9.
When Bitmap-NC is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NC shall be set to zero.
For index between NSCus+1 and 127, the m values are set to 0.
Q.7.9.3

C-SEGUE3 (replaces 10.8.16)

The duration of C-SEGUE3 is 18 symbols. Following C-SEGUE3, the ATU-C completes the initialization and enters
C-SHOWTIME. In C-SHOWTIME, ATU-C shall transmit the signal using Bitmap-FR and Bitmap-NR with the sliding
window.
When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbols.

- 258 -

Q.7.9.4

C-RATES-RA (supplements 10.8.3)
Table Q.16/G.992.1 – RRSI fields of C-RATES-RA←⎯⎯⎯⎯⎯ bits ⎯⎯⎯⎯→
fields7

6

RSF

B10 (AS0)

0

5

4

3

2

1

value of RSF
MSB

RSI

B8 (AS0)LSB

B9 (AS0)

value of RSI
MSB

S

I9

LSB

I8

value of S
MSB

I

I7

I6

FS(LS2)

0

I5

LSB
I4

I3

I2

I1

I0

value of FS(LS2) set to {000000002}

The RSI field has been extended to include bit B9 of BI (AS0) in bit 6, and The RSF field has been extended to include
the most significant bit B10 of BI (AS0) in bit 7, BI (AS0) being the number of payload bytes in the AS0 bearer channel
in the downstream interleave buffer. This is to support the higher data rates for the S=1/4, S=1/6 and S=1/8 modes.
The S field shall be coded {1001002) to indicate S=1/4, {1001102} to indicate S=1/6, and {1010002) to indicate S=1/8.
For the S=1/2n framing mode (see §Q.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
Q.7.10Exchange – ATU-R (supplements 10.9)

ATU-R shall transmit only the FEXTC symbols in R-MSGn, R-RATESn, R-B&G, R-CRCn. In other signals, the
ATU-R shall transmit both FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shallnot transmit NEXTC symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is definedin Figure Q.27.
Q.7.10.1

R-MSG-RA (supplements 10.9.2)

Replace Table 10-15 with Table Q.17.

- 259 -

Table Q.17/G.992.1 – Assignment of 80 bits of R-MSG-RA (Annex Q-EU)
Suffix(ces) of mi(Note)
79-72
71 - 70
69, 68
67-56

Parameter
All reserved bits shall be set to 0
Reserved for ITU-T
Extension to number of RS payload bytes, K
Extension to number of tones carrying data (ncloaded)
Bfast-max

55-49
48-40
39-32
31-25
24-21
20-16

Number of RS overhead bytes, (R)
Number of RS payload bytes, K
Number of tones carrying data (ncloaded)
Estimated average loop attenuation
Coding gain
Performance margin with selected rate option

15 - 14

Extension to total number of bits per DMT symbol, Bmax

13-12
11-0

Maximum Interleave Depth downstream
Total number of bits per DMT symbol, Bmax

NOTE – Within the separate fields the least significant bits have the lowest subscripts.

Q.7.10.1.1

Total number of bits supported (Bmax) (replaces 10.9.2.8)

This parameter shall be defined as in R-MSG2, see Q.7.9.1.
Q.7.10.1.2

Bfast-max (new)Bfast-max is the maximum number of bits of the fast buffer for fast data transmitted on the condition that the bits of thefast data can be equally assigned to all FEXT-symbols and NEXT-symbols.
Fast Buffered Data Bfast-max is tf.
Q.7.10.2

R-MSG2 ( supplements 10.9.8)

Table Q.18/G.992.1 – Assignment of 32 bits of R-MSG2
Suffix(ces) of mi (Note 1)
Parameter (Note 2)
31-25
Estimated average loop attenuation
24-21
Reserved for future use
20-16
Performance margin with selected rate option
15 - 14
13-12
11-0

Extension to total number of bits per DMT symbol, Bmax
Reserved for future use
Total number of bits per DMT symbol, Bmax

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
N1R-MSG2 = 10
N2R-MSG2 = 20
Q.7.10.2.1

Total number of bits per symbol supported (supplements 10.9.8.3)

The maximum number of bits per symbol that the downstream channel can support is encoded into bits 15, 14 and 11 –0.

- 260 -

The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTR and
NEXTR downstream channel performance. For example, if the maximum numbers of bits that can be supported in
FEXTR and NEXTR symbols are 111 and 88, the total number of bits per symbol supported is (111 x 126 + 88 x
214)/340 = 96.
NOTE – The number of symbols per hyperframe is 340, the number of FEXT symbols is 126, and the number of NEXTsymbols is 214.
Q.7.10.2.2 Estimated average downstream loop attenuation (supplements 10.9.8.1)
For Annex Q-EU, see A.3.3.
Q.7.10.3 R-REVERB5 (supplement of 10.9.12)
The duration of R-REVERB5 is 345n-40, 3<=n<=19, when NSCu=128, or 3<=n<=16 when NSCu=32.

Q.7.10.4

R-B&G (replaces 10.9.14)

The purpose of R-B&G is to transmit to ATU-C the bits and gains information, Bitmap-FR {b1, g1, b2, g2, ...,bNSCds-1, gNSCds-1}, and Bitmap-NR {bNSCds+1, gNSCds+1, bNSCds+2, gNSCds+2, ..., b2*NSCds-1,
g2*NSCds-1}, to be used on the downstream subcarriers. bi of Bitmap-FR indicates the number of bits to be coded by
ATU-C transmitter onto the i th downstream subcarrier in FEXTR symbols; gi of Bitmap-FR indicates the scale factor
that shall be applied to the i th downstream subcarrier in FEXTR symbols, relative to the gain that was used for thatcarrier during the transmission of C-MEDLEY. Similarly, bi of Bitmap-NR indicates the number of bits onto the (i –NSCds) th downstream carrier in NEXTR symbols; gi of Bitmap-NR indicates the scale factor that shall be applied tothe (i – NSCds) th downstream carrier in NEXTR symbols. Because no bits or energy will be transmitted at DC or
one-half the sampling rate, b0, g0, bNSCds, gNSCds, b2*NSCds, and g2*NSCds are all presumed to be zero, and are
not transmitted. When subcarrier 64 is reserved as the pilot tone, b64 and bNSCds+64, shall be set to 0, g64 andgNSCds+64 shall be set to gsync. When subcarrier 96 is reserved as the pilot tone, b96 and bNSCds+96, shall be set to0, g96 and gNSCds+96 shall be set to gsync. When subcarrier 128 is reserved as the pilot tone, b128 and bNSCds+128,
shall be set to 0, g128 and gNSCds+128 shall be set to gsync. When subcarrier 256 is reserved as the pilot tone, b256
and bNSCds+256, shall be set to 0, g256 and gNSCds+256 shall be set to gsync.The value gsync represents the gain
scaling applied to the sync symbol.
Each bi is represented as an unsigned 5-bit integer, with valid bi lying in the range of zero to Ndownmax, the maximum
number of bits that the ATU-C is prepared to modulate onto any subcarrier, which is communicated in C-MSG1.
Each gi is represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of thethird most significant bit. For example, a gi with binary representation (most significant bit listed first) 001.010000002
would instruct the ATU-C to scale the constellation for carrier i by a gain factor of 1.25, so that the power in that carrier
shall be 1.94 dB higher than it was during C-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
The R-B&G information shall be mapped in a (2*NSCds-2)*16-bit ((2*NSCds-2)*2 byte) message m defined by:
m = {m(2*NSCds-2)*16-1, m(2*NSCds-2)*16-2, …, m1, m0} = { g2*NSCds-1, b2*NSCds-1, …, g NSCds+1, b(Q.10-3)
NSCds+1, g NSCds-1, b NSCds-1, …, g1, b1},
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in(2*NSCds-2)*2 symbols, using the transmission method as described in 10.9.8.

- 261 -

When Bitmap-NR is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NR shall be set to zero.
Q.7.10.5

R-SEGUE5 (replaces 10.9.17)

The duration of R-SEGUE5 is 13 symbols. Following R-SEGUE-5, ATU-R completes the initialization and enters
R-SHOWTIME. In R-SHOWTIME, ATU-R shall transmit the signal using Bitmap-FC and Bitmap-NC with the sliding
window.
When Bitmap-NC is disabled (FEXT Bitmap mode), ATU-R shall not transmit NEXTC symbols.

- 262 -

ATU-CC-FLAG2(G.994.1)

C-GALF2(G.994.1)≥ 128≤ 2048C-QUIET2(Note 5)345n(n ≤ 38)

ATU-R

If R-ACK2then
C-PILOT1

If R-ACK1then
C-PILOT1AR-GALF2(G.994.1)

Beginning ofHyperframe

R-QUIET2≤ 15500

345n(1 ≤ n ≤ 33)≤ 32
Beginning ofHyperframe

1725

C-QUIET3A(Note 2)

R-FLAG2(G.994.1)

R-REVERB1
1536

C-REVERB1
12477(Note 5)9216

C-PILOT2(Note 4)

1536

C-ECT

(Note 2)

(Note 5)4608

C-REVERB2

1536

If R-ACK2 then C-PILOT3
If R-ACK1 then C-QUIET53628

C-REVERB3

20

C-SEGUE1

2884

C-RATES1/C-CRC1
C-MSG1/C-CRC2

Last symbol
may beshortened byn samples

R-QUIET3≥ 6144≤ 6145

R-ECT

1536

R-REVERB2≥ 3634≤ 3643

R-SEGUE1

5 ≤, ≤ 14(Note 2)

(Note 1)Introduction ofguard time

R-REVERB3
345n + 208(0 ≤ n ≤ 7)

49152
C-MEDLEY

345n - 13(9 ≤ n ≤ 16)
R-SEGUE2

13

R-RATES1/R-CRC1
R-MSG1/R-CRC2

1254

R-MEDLEY

49152(Note 3)(Note 2)

T1532900-99

Figure Q.26/G.992.1 – Timing diagram of the initialization sequence – Part 1- 263 -

(Note 4)NOTE 1 – The ATU-C shall transmit the FEXTR symbols, and shall not transmit as NEXTR symbols except the pilot
tone.
NOTE 2 – The ATU-C shall transmit both FEXTR and NEXTR symbols, when Bitmap-NR is enabled (Dual Bitmapmode). ATU-C shall not transmit the NEXTR symbols except pilot tone, when Bitmap-NR is disabled(FEXT Bitmap mode).
NOTE 3 – The ATU-R shall transmit the FEXTC symbols, and shall not transmit the NEXTC symbols.
NOTE 4 – The ATU-R shall transmit both FEXTC symbols, when Bitmap-NC is enabled (Dual Bitmap mode).
ATU-R shall not transmit NEXTC symbols, when Bitmap-NC is disabled (FEXT Bitmap mode).
NOTE 5 – The ATU-C shall transmit both FEXTR and NEXTR symbols.

- 264 -

Figure Q.27/G.992.1 – Timing diagram of the initialization sequence – Part 2[Editor’s note: Need to update Figure Q.27 to parameterize the length of C-B&G and the maximum length of RREVERB5.]
Q.8

AOC On-line adaptation and reconfiguration (pertains to clause 11)

Q.8.1.1

Bit swap request (replaces 11.2.3)

The receiver shall initiate a bit swap by sending a bit swap request to the transmitter via the AOC channel. This request
tells the transmitter which subcarriers are to be modified. The format of the request is shown in Table Q.19.

Table Q.19/G.992.1 – Format of the bit swap request message
Message header{111111112}(8 bits)

Bitmap index(1 bit)Message field 1-4
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

The request shall comprise nine bytes as follows:• an AOC message header consisting of 8 binary ones;• message fields 1-4, each of which consists of a one-bit bitmap index, subchannel index bits 10 & 9, and a five-bit
command followed by bits 8 to 1 of the subchannel index. One-bit bitmap index, subchannel index bits 10 & 9,
and valid five-bit commands for the bit swap message shall be as shown in Table Q.20. In Table Q.20, the MSB
for the bit swap request command represents the Bitmap index. For downstream data, Bitmap index equals 0
indicates Bitmap-FR, and Bitmap index equals 1 indicates Bitmap-NR. Similarly for upstream data, Bitmap
index equals 0 indicates Bitmap-FC, and 1 indicates Bitmap-NC. The next 2 bits are subchannel index bits 10 &9. The ten-bit subchannel index is counted from low to high frequencies with the lowest frequency subcarrier
having the number zero. The subcarrier index zero shall not be used;• the bit swap between FEXTC/R symbols and NEXTC/R symbols is not allowed.

Table Q.20/G.992.1 – Bit swap request commandValue(8 bit)yzz000002

Interpretation
Do nothing

yzz000012
yzz000102

Increase the number of allocated bits by one

yzz000112
yzz001002

Increase the transmitted power by 1 dB

yzz001012
yzz001102

Increase the transmitted power by 3 dB

yzz001112
yzz01xxx2

Reduce the transmitted power by 2 dB

Decrease the number of allocated bits by one
Increase the transmitted power by 2 dB
Reduce the transmitted power by 1 dB
Reserved for vendor discretionary commands

NOTE – y is "0" for FEXTC/R symbols, and "1" for NEXTC/R symbols of the Sliding Window.
NOTE – subchannel index = zz2*256 + subchannel index value from lower 8 bit field
The bit swap request message (i.e. header and message fields) shall be transmitted five consecutive times.

- 265 -

To avoid gi divergence between ATU-C and ATU-R after several bit swaps, for a gi update of ∆ dB the new gi value
should be given by:

g i ' = (1 / 256) × round (256 × g i × 10 exp(∆ / 20))
Q.8.1.2(Q.11-1)

Extended bit swap request (supplements 11.2.4)

The format of the extended bit swap request is shown in Table Q.21.

Table Q.21/G.992.1 – Format of the bit swap request message
Message header{111111002}(8 bits)

Bitmap index(1 bit)Message field 1-6
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

In the same manner as the bit swap request, each of the message fields of the extended bit swap request consists of
one-bit bitmap index, a five-bit command followed by a related ten-bit subchannel index.
Q.8.1.3

Bit swap acknowledge (supplements 11.2.5)

The bit swap superframe counter number shall only indicate the last superframe (SPF#4) of a hyperframe.
The new bit and/or transmit power table(s) shall then take effect starting from the first frame (frame 0) of SPF#0 of a
hyperframe.
If the bit swap superframe counter number contained in the received bit swap acknowledge message does not indicate
SPF#4, then the new table(s) shall take effect starting from frame 0 of SPF#0 of the next hyperframe.
Q.9

POTS splitter

For operation according to G.992.1 Annex Q-EU, the Annex E.4/G.992.3 requirements applying over a frequency band
up to 1104 kHz, shall be met over a frequency band up to 3750 kHz.

- 266 -

資料５
G.992.1 ANNEX I-EU (REVISION 1.1)
PROPRIETARY EXTENSION TO G.992.1 ANNEX I

This document defines G.992.1 Annex I-EU (Double spectrum downstream with extended upstream spectrum), a
proprietary extension to G.992.1 Annex I to extend the data rate beyond 2 Mbit/s upstream by way of:• Increase upstream bandwidth Æ increased number of subcarriers, NSCus=64• Increased bit loading, beyond 15 bits/bin
Due to the increase in upstream data rates, the upstream maximum interleave depth has been increased to 16. Support ofthis is mandatory.
The attached text is the approved text for Annex I, marked up with revision control to show the changes necessary tosupport the additional functionality.
Revision 1 text is based on G.992.1 Annex Q-EU Revision 3, and supports the following features:• extended upstream to subcarrier 64• high bit loading (HBL),• overlapped spectrum,• S=1/4 mandatory, S=1/3 not supported• D=16 upstream mandatory
Revision 1.1 changes the following with respect to Revision 1:• changes PRD and PRU polynomial for MEDLEY (REVERB is unchanged) by defining new PRDm and PRUm.
• specifies the non-overlapped downstream PSD mask.
• makes upstream masks EU-36 to EU-64 optional for use with non-overlapped spectrum as well as overlapped
spectrum, and adds associated downstream masks DS-36 to DS-60 for non-overlapped spectrum.
• added a new G.994.1 NPar(3) code point to indicate support for the optional EU masks with non-overlapped
spectrum. Changed the bit assignments for the mode 1 upstream masks and mode 2 upstream masks from
NPar(2) to NPar(3) within the extended upstream branch of the tree. Changed bit assignments for the EU-32 to
EU-64 NPar(3) code points.
• Modified timing diagram for initialization in Figure I.27(Text in C-B&G and R-REVERB5 has been change)- 267 -

ANNEX I-EU
Specific requirements for an ADSL system to support upstream data rates greater than 2 Mbit/s with improved
performance on short loops operating in the same cable as ISDN as defined in ITU-T Recommendation G.961
Appendix III

I.1

Scope

This annex describes those specifications that are unique to an ADSL system coexisting in the same binder as
TCM-ISDN as defined Recommendation G.961 Appendix III. The subclauses in this annex provide supplementary andreplacement material to the clauses in the main body. The nature of the material is parenthetically indicated in the
subclause heading. The modifications described in this annex allow a performance improvement from the ADSL system
specified in Annex C for short loops in an environment coexisting with TCM-ISDN in the same cable. Specifically, thisAnnex specifies extensions to upstream bandwidth and maximum bit loading to support upstream data rates greater than
2 Mbit/s. This annex also defines those parameters of this ADSL system that have been left undefined in the main bodyof this Recommendation. An ADSL system implementing Annex I-EU shall support Annex I. It is recommended that an
ADSL system implementing Annex I also implements Annex C.
I.2

Definitions

Bitmap-FC
Bitmap-FR
Bitmap-NC
Bitmap-NR
Dual Bitmap
FEXT Bitmap
FEXTC duration
FEXTC symbol
FEXTR duration
FEXTR symbol
Hyperframe
NEXTC duration
NEXTC symbol
NEXTR duration
NEXTR symbol
NSCds

NSCus
NSWF
Subframe
TTR
TTRC
TTRR
UI

ATU-R transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-R
ATU-R transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-R
The Dual Bitmap method has dual bit rates under the FEXT and NEXT noise from TCM-ISDN
Similar to the Dual Bitmap method however transmission only occurs during FEXT noise fromTCM-ISDN
TCM-ISDN FEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN FEXTTCM-ISDN FEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN FEXT
5 Superframes structure which synchronized TTR
TCM-ISDN NEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN NEXT
TCM-ISDN NEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN NEXT
The highest subcarrier index that can be used for downstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCds = 256 for a downstream
channel using the frequency band up to 1.104MHz; NSCds = 512 for a downstream channel
using the frequency band up to 2.208MHz.
The highest subcarrier index that can be used for upstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCus = 64 for an upstream
channel using the frequency band up to 276 kHz.
Sliding Window frame counter10 consecutive DMT symbols (except for sync symbols) according to TTR timing
TCM-ISDN Timing Reference
Timing reference used in ATU-C
Timing reference used in ATU-R
Unit Interval

I.3

Reference Models

I.3.1

ATU-C transmitter reference model (replaces figures in 5.1)

See Figure I.1 and Figure I.2.

- 268 -

"Bits""Bits" &"Gains"
2*NSCds-1

AS0
AS1
AS2
AS3
LS0
LS1
LS2
NTR

crcf
Mux/
Sync
Control

crci

scram
&
FEC

Rate
converter

scram
&
FEC

Interleaver

Toneordering

Rate
converter

Constellation
encoderandgainscaling

2*NSCds-2
480
IDFT

OutputParallel/
SerialBuffer

1
n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameZi
C
i=1 to NSCds-1
Constellation
Encoder Input
Data FrameB
FEC Output
Data Frame

U-C

T1532760-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure I.1/G.992.1 – ATU-C transmitter reference model for STM transport
Annex I-EU does not currently support STM transport. It only supports ATM transport.

"Bits""Bits" &"Gains"
2*NSCds-1

AS0
ATM0

Cell TC
crcf

AS1
ATM1

Cell TC

NTR

Mux/
Sync
Control
crci

scram
&
FEC

scram
&
FEC

Rate
converterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

2*NSCds-2
480
IDFT
1

OutputParallel/
SerialBuffer

n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to NSCds-1
Constellation
Encoder Input
Data Frame

U-C

T1532770-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure I.2/G.992.1 – ATU-C transmitter reference model for ATM transport- 269 -

I.3.2

ATU-R transmitter reference model (replaces figures in 5.2)

See Figure I.3 and Figure I.4.

"Bits""Bits" &"Gains"LS02*NSCus-1
crcf

LS0
LS1

Mux/
Sync
ControlLS2

crci

scrambler&
FEC

scrambler
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

2*NSCus-2
59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR

B
FEC Output
Data Frame

Zi
i=1 to NSCus-1
C
Constellation
Encoder Input
Data Frame

U-R

T1532780-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (1.104 MHz).

Figure I.3/G.992.1 – ATU-R transmitter reference model for STM transport
Annex I-EU does not currently support STM transport. It only supports ATM transport.

- 270 -

"Bits"

2*NSCus-1

LS0
Cell TC

ATM0

LS1Cell TC

ATM1"Bits" &"Gains"

crcf
Mux/
Sync
Control
crci

scrambler&
FEC

scrambler&
FEC

2*NSCus-2

RateconverterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR

B
FEC Output
Data FrameZi
C
i=1 to NSCus-1
Constellation
Encoder Input
Data Frame

U-R

T1532790-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (1.104 MHz).

Figure I.4/G.992.1 – ATU-R transmitter reference model for ATM transport
I.3.3
I.3.3.1

ATU-C/R transmitter timing model (replacement for 5.3)
TCM-ISDN crosstalk timing model (new)Figure I.5 shows the timing chart of the crosstalk from TCM-ISDN.

- 271 -TTR
377 UI
receive ISDN

transmit ISDNCO

0 ≤ propagation delay ≤ 16 UI
RT

6-7.5 UI

377 UI

receive ISDN

transmit ISDN

FEXTR

NEXTR

SC
TTRC

ATU-C TX

Frame Frame0 ≤ propagation delay ≤ 18.5 UI

Received
TTRC

SR

TTRR
NEXTC
ATU-R TXFEXTC

Frame Frame
T1532800-99

1 UI = 3.125 µs
FEXTR and NEXTR are estimated by ATU-CFEXTC and NEXTC are estimated by ATU-R

TTR

TCM-ISDN timing reference

TTRC

Timing reference used in ATU-C

Received TTR C Received TTRC at ATU-R
TTRRTiming reference used in ATU-R

SC

55 × 0.9058 µs: Offset from TTR to TTRC

SR

–42 × 0.9058 µs: Offset from received TTRC to TTRR

Figure I.5/G.992.1 – Timing chart of the TCM-ISDN crosstalk

The data stream of TCM-ISDN is transmitted in TTR period. CO transmits the stream in the first half of the TTR period
and RT transmits in the second half of the TTR period. ATU-C receives NEXT noise from the ISDN in the first half of
the TTR period and FEXT noise from the ISDN in the second half of the TCM-ISDN period. On the other hand,
ATU-R receives FEXT noise from the ISDN in the first half of the TTR period and NEXT noise from the ISDN in thesecond half of the TTR period.
As defined in I.7.6.2 and I.7.8.3, the ATU-C shall estimate the FEXTR and NEXTR duration at ATU-R, and the
ATU-R shall estimate FEXTC and NEXTC duration at ATU-C taking propagation delay on the subscribe line into
consideration.
The ATU-C shall transmit any symbols by synchronizing with the TTRC. The ATU-R shall transmit any symbols
synchronizing with the TTRR generated from received TTRC.

- 272 -

I.3.3.2

Sliding window (new)Figure I.6 shows the timing chart of the transmission for the Annex I-EU downstream at ATU-C.
Hyperframe = 345 symbols

TTRC
Crosstalk
period

FEXTR

FEXTR

FEXTR

FEXTR
NEXTR

NEXTR

ATU-C
T Frame
SWB
T1532810-99

FEXTR symbol
NEXTR symbol

Sliding Window

Figure I.6/G.992.1 – Sliding window for downstream symbols

The Sliding Window defines the transmission symbols under the crosstalk noise environment synchronized to theperiod of TTR. The FEXTC/R symbol represents the symbol completely inside the FEXTC/R duration. The NEXTC/R
symbol represents any symbol containing the NEXTC/R duration. Thus, there are more NEXTC/R symbols than
FEXTC/R symbols.
The ATU-C decides which transmission symbol is FEXTR or NEXTR symbol according to the sliding window andtransmits it with the corresponding bit table. Similarly, the ATU-R decides the transmission symbol is a FEXTC or
NEXTC and transmits it with the corresponding bit table. Although the phase of the sliding window is asynchronouswith TTRC/R, the pattern is fixed to the 345 frames of the hyperframe.
I.3.3.3

ATU-C Symbol Synchronization to TTR (new)345 symbols are 34 cycles with cyclic prefix of TTRC (or 32 cycles of TTRC without cyclic prefix). This implies a PLL
lock at the ATU-R.
I.3.3.4

Dual Bitmap switching (new)The ATU-C transmits FEXTR symbols using Bitmap-FR (in FEXTR duration), and transmits NEXTR symbols using
Bitmap-NR (in NEXTR duration) according to the result of initialization. The ATU-R transmits FEXTC symbols using
Bitmap-FC (in FEXTC duration), and transmits NEXTC symbols using Bitmap-NC (in NEXTC duration) in the samemanner.
The ATU-C shall have the capability to disable Bitmap-NC and Bitmap-NR (see I.4.5 and I.5.3).
I.3.3.5

Loop timing at ATU-R (new)The phase relation between received symbol and transmitted symbol of ATU-R at the reference point U-R shall meetthe phase tolerances as shown in Figure I.7.

- 273 -

(point U-R)
ATU-R receive
DMT symbol

ATU-R transmit
DMT symbol
T1532820-99±4.5 µs + SR

Figure I.7/G.992.1 – Loop timing for ATU-R

I.4

ATU-C functional characteristics (pertains to clause 7)

I.4.1

STM transmission protocols specific functionality (pertains to 7.1)

I.4.1.1

ATU-C input and output V interface for STM transport (replaces figure in 7.1.1)

See Figure I.8.

AS0 (n0 × 32 kbit/s)
AS1 (n1 × 32 kbit/s)
AS2 (n2 × 32 kbit/s)
AS3 (n3 × 32 kbit/s)
Digital
Network

twisted pair

LS0 ("C"; 16 or m0 × 32 kbit/s)

ATU-C

LS1 (m1 × 32 kbit/s)
LS2 (m2 × 32 kbit/s)
NTR
TTR
Operations, maintenance and control

T1532830-99

V-C
NOTE 1 – Optional bearer channels (both duplex and simplex) and features are shown with dotted lines.
NOTE 2 – TTR may be generated in the ATU-C without being provided from the V-C reference point.

Figure I.8/G.992.1 – ATU-C functional interfaces for STM transport at the V-C reference point- 274 -

I.4.1.2

Payload transfer delay (supplements 7.1.4)

Since Annex I-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.1.4.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
I.4.2
I.4.2.1

ATM transmission protocols specific functionalities (pertains to 7.2)
ATU-C Input and Output V interface for ATM transport (replaces figure in 7.2.1)

See Figure I.9.

ATM layer

ATM0
Tx_ATM0P
O
RT0

Tx_Cell_Handshake0
Rx_ATM0
Rx_Cell_Handshake0

ATM1
P
O
R
T
1

Twisted pair

Tx_ATM1
ATU-C
Tx_Cell_Handshake1
Rx_ATM1
Rx_Cell_Handshake1
NTR

and interface to
Digital network

TTR
Operations, administration,
maintenance and control
V-C

T1532840-99

NOTE – TTR can be generated in the ATU-C without being provided from the V-C reference point.

Figure I.9/G.992.1 – ATU-C functional interfaces to the ATM layer at the V-C reference point

I.4.2.2

Payload transfer delay (supplements 7.2.2)

Since Annex I-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.2.2.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
I.4.3
I.4.3.1

Framing (pertains to 7.4)
Superframe structure (supplements 7.4.1.1)

Since the rate converter reorders the user data and overhead bit-level data to create hyperframes, the input data frames
to the constellation encoder are different than those defined in 7.4.1.1.

- 275 -

I.4.3.2

Hyperframe structure (replaces 7.4.1.3)

Annex I-EU uses the hyperframe structure shown in Figure I.10. Figure I.10 shows the phase relationship between the
TTRC and the hyperframe at the point U-C. Each hyperframe is composed of 5 superframes, which are numbered from0 to 4. In order to indicate the boundary of the hyperframe, the inverse synch symbol is used for the 4th superframe(SPF#3), which is generated from a tone-by-tone 180-degree phase reversal of the synchronization symbol (see I.4.7.1)
except for the pilot tone.
The bit-level data stream from the rate-converter is extracted according to the size of Bitmap-FR and Bitmap-NR using
the Sliding Window (see I.3.3.2).
In order to make the bit rate to be a multiple of 32 kbit/s, the dummy bits are inserted at the end of hyperframe by therate converter (see I.4.4.2). The hyperframe is composed of 345 DMT symbols, numbered from 0 to 344. Each symbol
is assigned as FEXTR or NEXTR symbol in a FEXTR or NEXTR duration (see I.2), and the following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-C transmitter (see Figure I.11).
For Ndmt = 0, 1, ..., 344

S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > a + b) }elsethen FEXTR symbol
then NEXTR symbol

where a = 1243, b = 1461
Thus, 128 DMT symbols are allocated in the FEXTR duration, and 217 DMT symbols are allocated in the NEXTR
duration. The symbols are composed of:
FEXTR symbol:
Number of symbol using Bitmap-FR
Number of synch symbol
Number of inverse synch symbol
NEXTR symbol:

= 126
=1
=1

Number of symbol using Bitmap-NR= 214

Number of synch symbol=3

During FEXT Bitmap mode, the ATU-C shall transmit only the pilot tone in NEXTR symbols.

- 276 -

5 Superframe (= 340 frames)(point B)
1 Superframe = 68 frames (17 ms)

1 frame = 250 µs
Rate-Converter(point U-C, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#27

TC#33

TTR
ATU-R
Crosstalk

NEXT

FEXT

FEXT

Hyperframe = 345 symbols (85 ms)
SPF#1

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol F F F F N N N N N N F F

SSliding window

SPF#2
S

S

SPF#3
N F I

Inverse synch symbol

S

NEXTR Synch symbol

F

Symbol using Bitmap-FR (FEXTR duration bitmap)

N

Symbol using Bitmap-NR (NEXTR duration bitmap)

S

FEXTR Synch symbol

Figure I.10/G.992.1 – Hyperframe structure for downstream- 277 -SPF#4
F F

FEXTR duration

1 symbol = 246 µs
I

NEXT

N
T1532850-99

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

0
10
20
30

1

2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
21
22
23
24
25
26
27
28
29
40
31
32
33
34
35
36
37
38
39
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
SS
61
62
63
64
65
66
67
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100 101
101 102
103
104
105
106
107
108
109
110 111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
SS
132
133
134
135
136
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162 163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181 182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
SS
203
204
205
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233 234
235
236
237
238
239
240
241
242 243
253
244
245
246
247
248
249
250
251
252
263
254
255
256
257
258
259
260
260
262
264
265
266
267
268
269
270
271
272
273
274
276
277
278
279
280
281
282
283
ISS
284
285
286
287
288
289
290
291
292
293
295
296
297
298
299
300
301
302
303
294
304 305
306
307
308
309
310
311
312
313 314
315
316
317
318
319
320
321
322
323
324
334
325
326
327
328
329
330
331
332
333
SS
335
336
337
338
339
340
341
342
343
ISS

Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol
NEXTR data symbol

SS

NEXTR synch symbol
T1535330-00

Figure I.11/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Downstream

I.4.3.3

Subframe Structure (replaces 7.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table I.1. The 34 subframes forma hyperframe.

- 278 -

Table I.1/G.992.1 – Subframe (downstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

I.4.3.4

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Inverse Synch Symbol#344 is Synch Symbol

Reduced overhead framing with merged fast and sync bytes (modifies 7.4.3.2)

In S=1/2n framing mode (see §I.4.9), there are n Sync bytes per symbol time. The contents of the Sync bytes is thesame as in regular framing except that it repeats at n times the rate causing the superframe to be 68/n symbols in length.
The contents of the sync bytes are shown in Table 7-6/G.992.1. In S=1/2n framing mode, “Frame Number” in column 1
in Table 7-6/G.992.1 is replaced by “Sync Byte Index Number”.
As a result of the increase in superframe rate, the superframe contents is carried more frequently. For the case when
N=2, the EOC and AOC bandwidth doubles, thereby transferring actual messages at twice the rate. The CRC byte iscarried twice as frequently and therefore the maximum error rate rises from just over 58 per second to 117 per second.
Where the duration of an error condition is measured, this needs to be taken into consideration. The indicator bits arealso sent twice as often, which needs to be taken into consideration for statistics collection.
I.4.4

Dual Bitmapping and Rate Conversion (replaces 7.15)

The functions of the rate converter (see I.4.4.2), tone ordering (see I.4.6), constellation encoding, and gain scaling shalluse one of two bitmaps stored in the ATU. This method is called the dual bitmap.

- 279 -

I.4.4.1

Dual Bitmap (new)The Dual Bitmap method has individual bit rates under the FEXT and NEXT noise, and this needs an additional bit andgain table, {bi, gi}, and ordered bit table, b'i, for the tone ordering. The dual bitmaps are switched synchronized withthe sliding window pattern of NEXT/FEXT symbols. The number of bits and the relative gains to be used for every tone
are calculated in the bit loading algorithm during the initialization sequence, and transmitted in R-B&G.
I.4.4.2

Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FR, Bitmap-NR and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amount of fast and interleaved data in Bitmap-FR and Bitmap-NR shall be calculated with thefollowing formulae and illustrated in Figure I.12:
If tRf ≤ nRmax:n Rf = t Rf
nRi = nR − nRf
f Rf = t Rf
f Ri = f R − f Rf
If tRf > nRmax:

nRf = nR max

nRi = 0⎧⎡ t Rf × 10 − nRf × 6 ⎤⎪ f Rf 4 = ⎢
⎥
4
⎪
⎢
⎥
f Rf = ⎨⎡ t Rf ×10 − nRf × 7 ⎤⎪⎥⎪ f Rf 3 = ⎢3⎢⎥⎩⎧⎪ f Ri 4 = f R = f Rf 4
f Ri = ⎨⎪⎩ f Ri3 = f R − f Rf 3
Where:
tRf
tRi
fRf and nRf
fRf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FR and Bitmap-NR, respectively.
is the number of fast bits in Bitmap-FR if the subframe (see I.4.3.3) contains 3 Bitmap-FR except forsynch symbols.
fRf4
is the number of fast bits in Bitmap-FR if the subframe contains 4 Bitmap-FR except for synch
symbols.
fRi and nRi
are the numbers of interleaved bits in Bitmap-FR and Bitmap-NR, respectively.
nR
is the number of total bits in Bitmap-NR, which is specified in the B&G tables.
During FEXT Bitmap mode, nRf and nRi are zero.
To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tRf ≤ nRmax:- 280 -

dummy Rf = 0

dummy Ri = ( f Ri × 126 + nRi × 214) − t Ri × 340

If tRf > nRmax:()
dummy Rf 3 = ( f Rf × 3 + nRf × 7 ) − t Rf × 10

dummy Rf 4 = f Rf × 4 + nRf × 6 − t Rf ×10

dummy Ri = ( f Ri 4 × 96 + f Ri3 × 30 ) − t Ri × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FR constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:

dummy SRf = f Rf 3 − f Rf 4
The receiver shall determine Bitmap-FR and Bitmap-NR so that dummyRi is less than 126, dummyRf4 is less than 4 anddummyRf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.

- 281 -

#335#336#337#338#339#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25 #26 #27 #28 #29

tRi

Interleaved DatatRj

Fast Data

NOTE – Bit Ordering:
The earlier bit is located at the bottom
each symbol in this figure.
Rate Converter

Order

When tRf ≤ nRmax

fRi =fR – fRf

fR#4 #5 #6 #7 #8 #9

dummyRi#21 #22 #23#10 #11 #12 #13#0 #1 #2 #3#14 #15 #16 #17 #18 #19 #20#343#339#340#341#342#24 #25 #26 #27 #28 #29

nRinnRf=tRf R

fRf – tRf
FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe

When tRf > nRmax#0 #1 #2 #3#21 #22 #23#10 #11 #12 #13

dummyRi

fRi3

fRi4
dummyRf4

fR#335#336#337#338

dummyRf4

dummyRf3

dummy Rf4

fRf3
fRf4

#4 #5 #6 #7 #8 #9#14#15 #16 #17#18 #19 #20#26 #27 #28 #29#339#340#341#342#343

nRf = n
FEXTNEXT
Symbols Symbols
Subframe

FEXT
Symbols

NEXT
Symbols

Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe
T1532860-99

Figure I.12/G.992.1 – Bit distribution for Rate Converter under Dual latency and Dual Bitmap mode

I.4.5

FEXT Bitmapping (replaces 7.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (I.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures I.10 and I.16).
The Dual versus FEXT bitmapping mode is selected during G.994.1 using bit "DBM" (see 10.2 and 10.3).
I.4.6

Tone Ordering (replacement for 7.7)

A DMT time-domain signal has a high peak-to-average ratio (its amplitude distribution is almost Gaussian), and large
values may be clipped by the digital-to-analogue converter. The error signal caused by clipping can be considered as anadditive negative impulse for the time sample that was clipped. The clipping error power is almost equally distributed
across all tones in the symbol in which clipping occurs. Clipping is therefore most likely to cause errors on those tones- 282 -

that, in anticipation of a higher received SNR, have been assigned the largest number of bits (and therefore have thedensest constellations). These occasional errors can be reliably corrected by the FEC coding if the tones with the largest
number of bits have been assigned to the interleave buffer.
The numbers of bits and the relative gains in two bitmaps to be used for every tone are calculated in ATU-R receiver,and sent back to ATU-C according to a defined protocol (see 10.9.14). The pairs of numbers are typically stored, in
ascending order of frequency or tone numbers i, in bit and gain tables for Bitmap-FR and Bitmap-NR.
For Bitmap-FR, the "tone-ordered" encoding shall first assign fRf bits from the rate converter (see I.4.4.2) to the tones
with the smallest number of bits assigned to them, and the remaining fRi bits to the remaining tones. For Bitmap-NR, it
shall first assign nRf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nRi bits to the remaining tones.
All tones shall be encoded with the number of bits assigned to them; one tone in each bitmap may therefore have a
mixture of bits from the fast and interleaved buffers.
The ordered bit tables b'iF and b'iN shall be based on the original bit tables biF and biN as follows:
For k = 0 to Ndownmax {From the bit table, find the set of all i with the number of bits per tone bi = k
Assign bi to the ordered bit allocation table in ascending order of i}
Two ordered bit tables for Bitmap-FR and Bitmap-NR shall be prepared. A complementary de-ordering procedure
should be performed in ATU-R receiver. It is not necessary, however, to send the results of the ordering process to thereceiver because the bit tables FR and NR were originally generated in ATU-R, and therefore those tables have all theinformation necessary to perform the de-ordering.
I.4.7
I.4.7.1

Modulation (pertains to 7.11)
Inverse Synchronization Symbol (replaces 7.11.4)

Except for the pilot tone, Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phasereversal of Synchronization symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
I.4.7.2

Data subcarriers (modifies 7.11.1.1)

The channel analysis signal defined in 10.6.6 allows for a maximum of NSCds-1 carriers (at frequencies n∆f , n = 1 to
NSCds-1) to be used.
I.4.7.3

Nyquist frequency (modifies 7.11.1.3)

The carrier at the Nyquist frequency (#NSCds) shall not be used for user data and shall be real valued; other possible
uses are for further study.
I.4.7.4

Modulation by the inverse discrete Fourier transform (replaces 7.11.2)

The modulating transform defines the relationship between the 2*NSCds real values xn and the Zi:

xn =2* NSC −1⎛ jπni ⎞∑ exp⎜⎝ NSC ⎟⎠Zi =0i

for n = 0 to 2 * NSC − 1(7-21)The value of NSCds shall be 512 for this Annex.
The constellation encoder and gain scaling generate only NSCds-1 complex values of Zi. In order to generate realvalues of xn, the input values (NSCds-1 complex values plus zero at DC and one real value for Nyquist if used) shall beaugmented so that the vector Z has Hermitian symmetry. That is,- 283 -

Zi = conj (Z'2*NSCds-i)
I.4.7.5

for i = NSCds+1 to 2*NSCds-1(7-22)

Synchronization symbol (modifies 7.11.3)

The synchronization symbol permits recovery of the frame boundary after micro-interruptions that might otherwise
force retraining.
The data symbol rate, fsymb = 4 kHz, the carrier separation, ∆f = 4.3125 kHz, and the IDFT size, N = 2*NSCds, aresuch that a cyclic prefix of 15.625%*NSCds samples could be used. That is, when NSCds = 256, there are 40 samples
in the cyclic prefix.
(512 + 40) × 4.0 = 512 × 4.3125 = 2208

(7-23)

The cyclic prefix shall, however, be shortened to 12.5%*NSCds samples, and a synchronization symbol (with anominal length of NSCds*2.125 samples) is inserted after every 68 data symbols. That is,(2 + 0.125)*NSCds × 69 = (2 + 0.15625)*NSCds × 68(7-24)
The data pattern used in the synchronization symbol shall be the pseudo-random sequence PRD, (dn, for n = 1 to
2*NSCds) defined by:
dn = 1for n = 1 to 9
(7-25)
dn = dn-4 ⊕ dn-9

for n =10 to 2*NSCds(7-26)

The first pair of bits (d1 and d2) shall be used for the DC and Nyquist subcarriers (the power assigned to them is zero,so the bits are effectively ignored); the first and second bits of subsequent pairs are then used to define the Xi and Yi for
i = 1 to NSCds-1 as shown in Table 7-13.
The period of the PRD is only 511 bits, so dn+511 is equal to dn. The d1-d9 shall be re-initialized for eachsynchronization symbol, so each symbol uses the same data.
The two bits that modulate the pilot carrier, shall be overwritten by {0,0}: generating the {+,+} constellation.
The minimum set of subcarriers to be used is the set used for data transmission (i.e. those for which bi > 0); subcarriers

for which bi = 0 may be used at a reduced PSD as defined in transmit PSD paragraphs of Annexes A, B and C. The data
modulated onto each subcarrier shall be as defined above; it shall not depend on which subcarriers are used.
I.4.7.6

Cyclic prefix (replaces 7.12)

The last 12.5%*NSCds samples of the output of the IDFT (xn for n = 2*NSCds-0.125*NSCds to 2*NSCds-1) shall be
prepended to the block of 2*NSCds samples and read out to the digital-to-analogue converter (DAC) in sequence. For
example, when NSCds=256, the subscripts, n, of the DAC samples in sequence are 480 ... 511, 0 ... 511.
The cyclic prefix shall be used for all symbols beginning with the C-RATES1 segment of the initialization sequence, as
defined in 10.6.2.
I.4.8

ATU-C Downstream transmit spectral masks (replaces 7.14)

The downstream spectral masks of Annex I-EU are as specified in this section. When C-MSG1 bit 16 is 0, the PSD
mask as specified in § I.4.8.1 shall be used. When C-MSG1 bit 16 is 1, the PSD mask as specified in § I.4.8.2 shall be
used.
I.4.8.1

Downstream non-overlapped PSD mask definition

The non-overlapped PSD masks are defined with absolute peak values in Figure I.13. The low frequency stop band isdefined for frequencies below f1 kHz (tone n1); the high frequency stop band is defined at frequencies greater than
2208 kHz (tone 512). The in-band region of these PSD masks is the frequency band from f1 kHz to 2208 kHz.

- 284 -

–18 dB/octave

PSD indBm/Hz–36.5 dBm/Hz peak PSD–3 dB/octave–65 dB/octave

36 dB/octave–78 dB/octave–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHz–47.8 dBm/Hz–100 dBm/Hz peak PSD
in 10 kHz window
peak PSD
in 1 MHz window
above 3750 kHz–247 dB/octave–44.2 dBm/Hz–59.4 dBm/Hz–92.5 dBm/Hz–80 dBm/Hz–100 dBm/Hz

0

4

f3

f1

1104

1622

Frequency band f (kHz)0<f<4
4 < f < f3
f3 < f < f1
f1 < f < 1104
1104 < f < 1622
1622 < f < 2208
2208 < f < 2500
2500 < f < 3001.5
3001.5 < f < 3175
3925 < f < 12000

2208–110 dBm/Hz

3001.53750 4545
2500
3175

Equation for line (dBm/Hz)
-97.5
-92.5
-92.5 + 36*log2(f/f3)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 3.0*log2(f/1622)-47.8 – 65*log2(f/2208)-59.4 - 78*log2(f/2500)-80 – 247*log2(f/3001.5)-100

Frequency (kHz)04
4

PSD level (dBm/Hz)
-97.5
-97.5
-92.5

Measurement BW
100 Hz100 Hz100 Hz

f3
f1
f1
1104
1622
2208
2500
3001.5
3175
12000

-92.5
-44.2
-36.5
-36.5
-46.5
-47.8
-59.4
-80
-100
-100

10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz

Additionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
3750
4545
7225
12000

PSD level (dBm/Hz)
-100
-110
-112
-112

- 285 -

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

–112 dBm/Hz

7225

12000

Frequency
in kHzThe corner frequencies f1 and f3 depend on the associated upstream PSD mask used, see §I.5.6) and are defined asfollows:
Mask designator(DS-mm)
DS-32
DS-36
DS-40
DS-44
DS-48
DS-52
DS-56
DS-60
DS-64
NOTE 1 –NOTE 2 –NOTE 3 –NOTE 4 –NOTE 5 –NOTE 6 –Associatedupstream mask
EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

f1 (kHz)f3 (kHz)138
155.25172.5
189.75207
224.25241.5
258.75
276

54.45
61.26
68.06
74.87
81.67
88.48
95.29
102.09108.9

All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint withfrequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued
the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that
this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.
Figure I.13: Non-overlapped Downstream Channel PSD Masks.

Spectral Shaping of the In-Band Region defined in I.4.8.3 and Transmit Signals with Limited Transmit Power definedin I.4.8.4 shall be applied.
I.4.8.2

Downstream Overlapped PSD mask definition

The overlapped PSD mask is defined with absolute peak values in Figure I.14. The low frequency stop band is definedfor frequencies below 25.875 kHz (tone 6); the high frequency stop band is defined at frequencies greater than
2208 kHz (tone 512). The in-band region of this PSD mask is the frequency band from 25.875 kHz to 2208 kHz.

- 286 -

–18 dB/octave

PSD indBm/Hz–36.5 dBm/Hz peak PSD–3 dB/octave–65 dB/octave

21 dB/octave–78 dB/octave–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHz–47.8 dBm/Hz–100 dBm/Hz peak PSD
in 10 kHz window
peak PSD
in 1 MHz window
above 3750 kHz–247 dB/octave–59.4 dBm/Hz–92.5 dBm/Hz–80 dBm/Hz–100 dBm/Hz

0425.8751104

1622

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < 1104
1104 < f < 1622
1622 < f < 2208
2208 < f < 2500
2500 < f < 3001.5
3001.5 < f < 3175
3925 < f < 12000

2208–110 dBm/Hz

3001.53750 4545
2500
3175

–112 dBm/Hz

7225

12000

Frequency
in kHzEquation for line (dBm/Hz)-97.5-92.5 + 21*log2(f/4)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 3.0*log2(f/1622)-47.8 – 65*log2(f/2208)-59.4 - 78*log2(f/2500)-80 – 247*log2(f/3001.5)-100

Frequency (kHz)04
4

PSD level (dBm/Hz)
-97.5
-97.5
-92.5

Measurement Bandwidth
100 Hz100 Hz100 Hz25.875
1104
1622
2208
2500
3001.5
3175
12000

-36.5
-36.5
-46.5
-47.8
-59.4
-80
-100
-100

10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz

Additionally, the PSD mask shall be satisfying following requirements:
Frequency (kHz)
3750
4545
7225
12000
NOTE 1 –NOTE 2 –NOTE 3 –PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement Bandwidth
1 MHz
1 MHz
1 MHz
1 MHz

All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint with- 287 -

frequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at themeasurement frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at
frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask
continued the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It wasrecognized that this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.

NOTE 4 –NOTE 5 –NOTE 6 –Figure I.14: Non-overlapped Downstream Channel PSD Mask.

I.4.8.3

Spectral Shaping of In-Band Region of PSD Spectrum

In order to shape the ATU-C PSD, frequency dependent gains, called spectral shaping values (ssvi ), shall be applied oneach tones during initialisation and showtime. The ssvi values shall be represented with 1 bit before and 10 bits after thedecimal point.
Table I.2 defines the corner points for the nominal PSD shape of the inband region as gain in dB, i.e log_ssvi. Log_ssvi
on other tones shall be linearly interpolated between corner points on a logarithmic scale for the gain (dB) and a linear
scale for the frequency (Hz). Note that the corner points defined in Table I.2 are relative values. Table I.3 defines thesimilar corner points for the overlapped spectrum.
The spectral shaping values shall be converted from logarithmic scale (log_ssvi, dB values) to linear ssvi values
according to:log_ ssvi⎛⎞⎜
Round ⎜1024 × 10 20 ⎟⎟⎝⎠ssvi =
1024

These points are not passed at initialization for the nominal PSD shape but are provided here for reference. However,for additional spectral shaping (see I.4.8.5), parameters are passed during G.994.1.
The combined accuracy of the process of linear interpolation of the log_ssvi values and the process of conversion tolinear ssvi values shall be strictly less than one half lsb of the 10 bit after the decimal point format of the linear ssvi
values. No error shall be introduced when log_ssvi equals 0dB or is interpolated between log_ssvi values, which equal
0dB.
NOTE 1:NOTE 2:

The above definition ensures that the maximum deviation between ssvi values used by transmitter andreceiver is one lsb.
The above needs an accuracy that is strictly < 1/2 lsb. An accuracy of = 1/2 lsb, will lead to inaccurate
results.

Table I.2: Corner points for the non-overlapped nominal in-band PSD shape.
Tone Index
n1

Log_ssvi (dB)
0

256
376
511

0
–10
–11.3

Comments
f1 kHz defines the beginning of the inband region. No shaping is applied in the
low stop band.
1104 kHz
1622 kHz ( –10 = -50 - Nominal_PSD_lowband)
2208 kHz ( –11.3 = -51.3 - Nominal_PSD_lowband)- 288 -

Table I.3: Corner points for the overlapped nominal in-band PSD shape
Tone Index
6

Log_ssvi (dB)
0

256
376
511

0
–10
–11.3

Comments
25.875 kHz defines the beginning of the inband region. No shaping is appliedin the low stop band.
1104 kHz
1622 kHz (–10 = -50 - Nominal_PSD_lowband)
2208 kHz (–11.3 = -51.3 - Nominal_PSD_lowband)

The absolute values of the transmit PSD are obtained by scaling the relative shaping values with a
NOMINAL_PSD_lowband, defined for the lower in-band frequencies. Note that the nominal in-band transmit PSD isfrequency dependent. The NOMINAL_PSD_lowband is –40 dBm/Hz (below 1104 kHz) for both the overlapped andnon-overlapped spectra.
NOTE 3: In-band PSD spectral shaping is applied prior to the IFFT.
NOTE 4: The value of MAXNOMATPds may be limited by regional regulations.
I.4.8.4

Transmit Signals with Limited Transmit PowerFor cases where the transmit signal must be limited to a maximum aggregate transmit power (e.g. ATPdsmax = +20dBm), thene)During initialization the PSD transmit level is specified as an offset from the nominal value, i.e.
(Nominal_PSD_lowband + ssvi – x – power cutback) dB, and all values of gi = 1 for the offset value x and power
cutback. The same value of offset x is used for both overlapped and non-overlapped cases. The value of x shall be
the greater of 0 dB and (21.3 – ATPdsmax) dB. For ATPdsmax = 20 dBm, the corresponding value of x shall be
1.3 dB.

b)

If bi>0, then valid range for gi is [-14.5 to +2.5+x] (dB) ;If bi>0, then gi shall be in the [gsync – 2.5 to gsync + 2.5] (dB) range;
If bi=0, then gi shall be equal to 0 (linear) or in the [-14.5 to gsync] (dB) range;
For G.992.1 annex I-EU, gsync <= x dB

The gi values shall be constrainted by following relation:
Constraint on gi values

511

2

2

i =6

I.4.8.5

511∑ ssvi ∗ gi ≤ ∑ ssvi

2

i =6

Additional inband spectral shaping

An ATU-R may request additional downstream inband spectral shaping by passing parameters to the ATU-C in a
G.994.1 MP, or MS message. The ATU-C may select additional downstream inband spectral shaping by passing
parameters to the ATU-R in a G.994.1 MS message. Within the framework of G.994.1, the ATU-C has the ability tomake the final decision on the downstream inband PSD shape to be used.
The additional inband spectral shaping parameters are listed in I.7.2.2 and defined in I.7.3. If the Additional inband
spectral shaping Spar(2) bit is set to ONE in Table I.7.4, its associated Npar(3) octets in Tables I.7.4.1 to I.7.4.1.5
define the inband spectral shape. If the additional inband spectral shaping Spar(2) bit is set to ZERO, its associatedNpar(3) octets are not transmitted and the nominal inband PSD shape defined in I.4.8.3 shall be used. These Npar(3)octets define the downstream PSD levels in the low band (between f1 and 1104 kHz), at 1622 kHz and at 2208 kHz.
The PSD levels between 1104 kHz and 1622 kHz, and between 1622 kHz and 2208 kHz are linearly interpolated in log
scale. The defined values are the PSD level in dB below the NOMINAL_PSD_lowband of –40dBm/Hz. For example, if
all three values are set to 20 dB, the result will be a flat PSD of –60dBm/Hz. If the three values are set to 2 dB, 12 dB
and 15.5 dB, the result is the PSD defined in I.4.8.1 reduced by 2dB. In order not to violate the PSD mask defined in
I.4.8.1, the second value shall be no less than 10 dB and the third value shall be no less than 11.3 dB.

- 289 -

I.4.8.6

Egress control

G.992.1 Annex I-EU equipment shall be able to reduce the PSD below –80 dBm/Hz for the Amateur radio band
between 1.81 MHz and 2.00 MHz. The ATU-C may apply additional spectral shaping as described in I.4.8.5 to help
achieve this requirement.
I.4.9

Support of higher downstream bit rates with S = 1/2n (replaces 7.6.4)

With a rate of 4000 data frames per second and a maximum of 255 bytes (maximum RS codeword size) per data frame,
the ADSL downstream line rate is limited to approximately 8 Mbit/s per latency path. The line rate limit can beincreased beyond this for the interleaved path by mapping 2n RS codewords into one FEC data frame (i.e. by using S =1/2n in the interleaved path). S = 1/2n shall be used in the downstream direction only over bearer channel AS0.
For a selected value of n ≥ 1, the KI data bytes per interleaved mux data frame shall be packed into 2n RS codewords,
split into n equal parts, each consisting of 2 consecutive RS codewords. This forces rate adaptation to occur in 32n
kbit/s increments. Each of the n parts of the data frame shall begin with a sync byte and shall obey the rules defined inTable I.4 for insertion of dummy bytes. The smallest value of n that can support the KI data bytes shall be used.
Support of S = 1/2 (i.e., n=1) and S = 1/4 (i.e., n=2) is mandatory.

The resulting data frame structure shall be as shown in Figure I.15.
N1
Sync
Byte

PayloadN2 = N 1 or N 1-1

R

PayloadR

N2n-1 = N1
Sync
Byte

PayloadN2n = N2

R

PayloadR

NI
Figure I.15 – Data frame for S = 1/2n mode
When KI is divisible by 2n, the 2n codewords have the same length N2i-1 = N2i = (KI/2n + RI) for i = 1 to n, otherwise
the odd numbered codewords are equal and are one byte longer than the even numbered codewords, i.e. N2i-1 =(KI + n)/2n + RI bytes, and N2i = (KI – n)/2n + RI bytes for i = 1 to n. For the FEC output data frame, NI =

∑ N,
n

i =1

i

with NI < 512n - 1 bytes.
The convolutional interleaver requires all codewords to have the same odd length. To achieve the odd codeword length,
insertion of dummy (not transmitted) bytes may be required. For S = 1/2n, the dummy byte addition to the odd
numbered and/or even numbered codewords at the input of the interleaver shall be as in Table I.4.

Table I.4/G.992.1 –Dummy byte insertion at interleaver input for S = 1/2n
N2i-1
Odd
Even
Odd
Even

I.5

N2i
Odd
Even
Even
Odd

Dummy Byte Insertion Action
No action
Add one dummy byte at the beginning of all codewords
Add one dummy byte at the beginning of each even numbered codeword
Add one dummy byte at the beginning of each odd numbered codeword and two dummy bytes
at the beginning of each even numbered codeword [the de-interleaver shall insert one dummy
byte into the de-interleaver matrix on the first byte and the (D + 1)th byte of the corresponding
codeword to make the addressing work properly]

ATU-R Functional Characteristics (pertains to clause 8)- 290 -

I.5.1
I.5.1.1

Framing (pertains to 8.4)
Superframe structure (replaces 8.4.1.1)

The superframe structure of ATU-R transmitter is identical to that of ATU-C transmitter, as specified in I.4.3.1.
I.5.1.2

Hyperframe structure (replaces 8.4.1.3)

The hyperframe structure of ATU-R transmitter is functionally similar to that of ATU-C transmitter, except that theinverse synch symbol is used in the 1st superframe (SPF#0) (see Figure I.16). The hyperframe is composed of 345
DMT symbols, numbered from 0 to 344. Each symbol is under FEXTC or NEXTC duration (see I.5.3), and thefollowing numerical formula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-R
transmitter (see Figure I.17).
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbol
then NEXTC symbol

128 DMT symbols are allocated in the FEXTC duration, and 217 DMT symbols are allocated in the NEXTC duration.
The symbols are composed of:
FEXTC symbol:
Number of symbol using Bitmap-FC
Number of synch symbol
Number of inverse synch symbol
NEXTC symbol:
Number of symbol using Bitmap-NC
Number of synch symbol

= 126
=1
=1
= 214
=3

During FEXT Bitmapping mode, the ATU-R shall not transmit any signal.

- 291 -

5 Superframe (= 340 frames)(point B)

1 Superframe = 68 frames (17 ms)

1 frame = 250 µs

Rate-Converter(point U-R, including synch symbol)
TC#6

TTR Clock(TC)#0 = 2.5 ms

TC#33

TTRR
ATU-R
Crosstalk

NEXT

NEXT

FEXT
Hyperframe = 345 symbols (85 ms)

FEXT

ATU-C transmit
DMT symbol N N N N N F F F F N N N

SPF#2

SPF#1

Superframe (SPF#0) = 69 symbols (17 ms)

N F F I F N

S

S

SPF#3

SPF#4
S

S
T1532870-99

Sliding window

FEXTC duration

1 symbol = 246 µs
I

Inverse synch symbol

S

NEXTC Synch symbol

F

Symbol using Bitmap-FC (FEXTC duration bitmap)

N

Symbol using Bitmap-NC (NEXTC duration bitmap)

S

FEXTC Synch symbol

Figure I.16/G.992.1 – Hyperframe structure for upstream- 292 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

ISS

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

101

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

SS

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

17

173

174

175

176

177

178

179

180

181

172
182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

SS

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

244

245

246

247

248

249

250

251

252

253

24

243

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

SS

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

SS

ISS Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol SS NEXTR synch symbol
NEXTR data symbol

T1535340-00

Figure I.17/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Upstream

I.5.1.3

Subframe structure (replaces 8.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table I.5. The 34 subframes forma hyperframe.

- 293 -

Table I.5/G.992.1 – Subframe (upstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

I.5.2

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Inverse Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Synch Symbol#344 is Synch Symbol

Dual Bitmapping and rate conversion (replaces 8.15)

The function of the rate converter (see I.5.2.2), tone ordering (see I.5.4), constellation encoding, and gain scaling shalluse one of two bitmaps stored in the ATU. This method is called the dual bitmap.
I.5.2.1

Dual Bitmap (new)The Dual Bitmap switching shall be the same as for the downstream data, specified in I.4.4.1. The number of bits andthe relative gains to be used for every tone are calculated in the bit loading algorithm during the initialization sequence,and transmitted in C-B&G.
I.5.2.2
Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FC, Bitmap-NC and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amounts of fast and interleaved data in Bitmap-FC and Bitmap-NC shall be calculated in thefollowing formulae:
If tCf ≤ nCmax:- 294 -

nCf = tCf
nCi = nC − nCf
f Cf = tCf
f Ci = f C − f Cf
If tCf > nCmax:

nCf = nC max

nCi = 0⎧⎡ tCf × 10 − nCf × 6 ⎤⎪ f Cf 4 = ⎢
⎥
4
⎪
⎢
⎥
f Cf = ⎨⎡ tCf ×10 − nCf × 7 ⎤⎪⎥⎪ f Cf 3 = ⎢3⎢⎥⎩⎧ f Ci 4 = f C − f C 4
f Ci = ⎨⎩ f Ci 3 = f C − f Cf 3
Where:
tCf
tCi
fCf and nCf
fCf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of fast bits in Bitmap-FC if the subframe (see I.5.1.3) contains 3 Bitmap-FC except
for synch symbols.
fCf4
is the number of fast bits in Bitmap-FC if the subframe contains 4 Bitmap-FC except for synch
symbols.
fCi and nCi
are the numbers of interleaved bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of total bits in Bitmap-NC, which is specified in the B&G tables.
nC
During FEXT Bitmap mode, nCf and nCi are zero.
To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tCf ≤ nCmax:

dummyCf = 0

dummyCi = ( f Ci × 126 + nCi × 214) − tCi × 340
If tCf > nCmax:()
dummyCf 3 = ( f Cf × 3 + nCf × 7 ) − tCf ×10

dummyCf 4 = f Cf × 4 + nCf × 6 − tCf ×10

dummyCi = ( f Ci 4 × 96 + f Ci 3 × 30) − tCi × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FC constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:
dummySCf = fCf3 – fCf4

- 295 -

The receiver shall determine Bitmap-FC and Bitmap-NC so that dummyCi is less than 126, dummyCf4 is less than 4 anddummyCf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.
I.5.3

FEXT Bitmapping (replaces 8.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (I.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures I.10 and I.16).
The Dual versus FEXT bitmapping mode is selected during G.994.1 using bit "DBM" (see 10.2 and 10.3).
I.5.4

Tone Ordering (pertains to 8.7)

The tone ordering algorithm shall be the same as for the downstream data, specified in I.4.4.
For Bitmap-FC, the "tone-ordered" encoding shall first assign fCf bits from the rate converter (see I.5.2.2) to the tones
with the smallest number of bits assigned to them, and the remaining fCi bits to the remaining tones. For Bitmap-NC, it
shall first assign nCf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nCi bits to the remaining tones. Two ordered bit tables for Bitmap-FC and Bitmap-NC shall be prepared.
I.5.5
I.5.5.1

Modulation (pertains to 8.11)
Inverse synchronization symbol (replaces 8.11.4)

Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phase reversal of Synchronization
symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
I.5.5.2

Gain scaling in synchronization symbol (new)At initialization time, the sync symbol reference transmit PSD level shall be set at the nominal PSD level+10log(gsync2) dBm/Hz, with gsync2 defined as the average gi2 value over the used (i.e. bi > 0) subcarriers in theNEXT or FEXT bitmap, whichever results in the highest average gain. The sync symbol reference transmit PSD shallnot be updated with used subcarrier gain changes during SHOWTIME.
I.5.5.3

Nyquist frequency (supplements 8.11.1.2)

The upstream Nyquist frequency for Annex I-EU shall be at subcarrier NSCus (f = 4.3125*NSCus kHz)..
I.5.5.4

Modulation by the inverse discrete Fourier transform (supplements 8.11.2)

For Annex I-EU, see A.2.1.
I.5.5.5

Synchronization symbol (supplements 8.11.3)

For Annex I-EU, see A.2.2.

I.5.6

ATU-R Upstream Transmit Spectral Mask (replaces 8.14)

The upstream PSD masks of Annex I-EU are defined with absolute peak values in Figure I.18. The low frequency stopband is defined for frequencies below 25.875 kHz; the high frequency stop band is defined at frequencies greater than
f1 kHz (tone n1). The in-band region of these PSD masks is the frequency band from 25.875 kHz to f1 kHz.
and the ATU-R may optionally support upstream masks EU-36 to EU-64. specified in Figure I.18
NOTE: The value of MAXNOMATPus may be limited by regional regulations.

- 296 -

PSD indBm/HzPEAKPSD(PEAKPSD+92.5)/2.69
dB/octave–72 dB/octave–100 dBm/Hz peak
–15 dB/octave–97.5
15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 1411 kHz–92.5 peak
PSD_int dBm/Hz–110 dBm/Hz–112 dBm/Hz

0425.875

f1

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < f1
f1< f < f_int
f_int < f < 686
f > 686
Frequency (kHz)04
425.875f1
f_int
686 – 12000

f_int

686

1411
1630 5275

Equation for line (dBm/Hz)-97.5-92.5+(PEAKPSD+92.5)* log2(f/4)/log2(25.875/4)
PEAKPSDPEAKPSD-72*log2(f/f1)
PSD_int-15*log2(f/f_int)-100
PSD level (dBm/Hz)
-97.5
-97.5
-92.5
PEAKPSDPEAKPSD
PSD_int-100

Measurement BW
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz

Additionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
1411
1630
5275
12000

Frequency
12000 in kHz

PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

NSCus is a function of the upstream mask parameters, which are defined as follows:- 297 -

Parameters in FEXT bitmap for mode 1, both bitmaps for mode 2 (see §I.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

32
64
64
64
64
64
64
64
64

Template
Nominal PSD
P0 (dBm/Hz)

-38.0
-38.5
-39.0
-39.4
-39.8
-40.1
-40.4
-40.7
-41.0

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.0
-35.5
-35.9
-36.3
-36.6
-36.9
-37.2
-37.5

138.00155.25172.50189.75207.00224.25241.50258.75276.00242.92274.03305.06336.33367.54399.07430.58462.04493.45

-93.2
-94.0
-94.7
-95.4
-95.9
-96.5
-97.0
-97.4
-97.9

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.2
-36.4
-37.2
-37.9
-38.3
-38.6
-38.8
-38.8

138.00155.25172.50189.75207.00224.25241.50258.75276.00242.92273.47302.26331.87361.55392.16423.12454.51486.91

-93.2
-94.0
-94.7
-95.3
-95.8
-96.4
-96.9
-97.3
-97.8

Parameters in NEXT bitmap for mode 1 (see §I.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

Template
NominalPSD P0(dBm/Hz)

32
64
64
64
64
64
64
64
64

-38.0
-38.7
-39.9
-40.7
-41.4
-41.8
-42.1
-42.3
-42.3

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

NOTE 1 – All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
NOTE 2 – The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The breakpoints
in the tables shall be connected by linear straight lines on a dB/log(f) plot.
NOTE 3 – MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint with frequency fi
is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next specified breakpoint.
NOTE 4 – The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
NOTE 5 – The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued the21.5 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that this might impact
V.90 performance, and so the floor was extended to 4 kHz.
NOTE 6 – All PSD and power measurements shall be made at the U-R interface (see Figures I.3 & I.4).
Figure I.18: Upstream Channel PSD Masks

I.5.7

Forward error correction (supplements 8.6)

The minimum FEC coding capabilities (Table 8-3) for an ATU-R shall include the following interleave depths for theinterleaved buffer:
D = 1, 2, 4, 8, and 16- 298 -

I.5.8Cyclic prefix (supplements 8.12)

For Annex I-EU, see A.2.3.

I.6

EOC Operation and Maintenance (pertains to clause 9)

I.6.1

ADSL line related primitives (supplements 9.3.1)

I.6.1.1

ADSL line related near-end defects (supplements 9.3.1.3)

Two near-end defects are further defined:••

I.6.1.2

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.
Severely errored frame (SEF): A SEF defect occurs when the content of two consecutively received ADSL
synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R, does notcorrelate with the expected content over a subset of the tones. An SEF defect terminates when the content of twoconsecutively received ADSL synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR
duration at ATU-R, correlate with the expected contents over the same subset. The correlation method, theselected subset of tones, and the threshold for declaring these defect conditions are implementation discretionary.
ADSL line related far-end defects (supplements 9.3.1.4)

Loss-of-signal is further defined:•

I.6.2
I.6.2.1

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.
Test Parameters (supplements 9.5)
Near-end test parameters (supplements 9.5.1)

The near-end primitives are further defined:••

I.6.2.2

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio (SNR) margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.
Far-end test parameters (supplements 9.5.2)

The far-end primitives are further defined:
•
•

I.6.3

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio SNR margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.
Data registers in the ATU-R (supplements 9.2.4)

For the S=1/2n framing mode (see §I.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
I.7

Initialization (pertains to clause 10)

I.7.1

Initialization with Hyperframe (replaces 10.1.5)- 299 -

The exchange of messages between ATU-C and ATU-R should be performed in FEXTC and FEXTR. The DMT
symbol has two symbol rates: one is 4.3125 kbaud for the symbol without a cyclic prefix, and the other is 4 x 69/68
kbaud for the symbol with a cyclic prefix. 32 times of the TTR has the same period as 345 times of the 4.3125 kbaud,
and 34 times of the TTR is the same as 345 times of 4 x 69/68 kHz.
During FEXT Bitmap mode, the ATU-R shall not transmit any signal during the NEXTC symbols duration and the
ATU-C shall transmit only the pilot tone as the NEXTR signal except:• C-PILOT1 (C-PILOT1A) which is accompanied by a signal to allow the ATU-C to indicate the phase of TTRC
to the ATU-R (see I.7.4.1);• C-QUIETn where no signal is transmitted.
The ATU-C begins transmitting C-PILOT1 at the beginning of the hyperframe without cyclic prefix. The ATU-C
informs the phase of the TTRC to ATU-R during C-PILOT1. The ATU-R begins transmitting R-REVERB1 at the
beginning of the hyperframe without cyclic prefix. The ATU-R performs the training of any receiver equalizer using
this phase information of the TTRR generated from received TTRC.
From C-PILOT1 to C-SEGUE1, the following numerical formula gives the information which duration Ndmt-th DMT
symbol belongs to at ATU-R (see Figure I.19).
For Ndmt = 0, 1, …344
S = 256 x Ndmt mod 2760
if { (S + 255 < a) or (S > a + b) }else
where a = 1243, b = 1461

then FEXTR symbols
then NEXTR symbols

In order to enter C-RATES1 at the beginning of the hyperframe with cyclic prefix, the number of symbols from
C-PILOT1 to C-SEGUE1 shall be a multiple of 345 DMT symbols.
From R-REVERB1 to R-SEGUE1, the following numerical formula gives the information which duration Ndmt-th
symbol belongs to at ATU-C (see Figure I.20).
For Ndmt = 0, 1, …, 344,
S = 256 x Ndmt mod 2760
if { (S > a) and (S + 255 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols

From C-RATES1 to C-SEGUE3, the number of symbols is a multiple of 345 DMT symbols. The following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-C transmits the message data in
FEXTR symbols (see Figure I.11).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760
if { (S + 271 ≥ a) and (S ≤ a + b) }else
where a = 1243, b = 1461

then NEXTR symbols
then FEXTR symbols

The ATU-R enters R-REVERB3 at the beginning of the hyperframe with cyclic prefix, which is extracted fromreceived signal. From R-REVERB3 to R-SEGUE5, the number of symbols is a multiple of 345 DMT symbols. The
following numerical formula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-R transmits
the message data in FEXTC symbols (see Figure I.17).
For Ndmt = 0, 1, ..., 344- 300 -

S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28

0

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
107
97
98
99
100
101
102
103
104
105
106
108
109
110
111
112
113
114
115
116
117 118
119
120
121
122
123
124
125
126
127
128
129 130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
161
151
152
153
154
155
156
157
158
159
160
162
163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
204
194
195
196
197
198
199
200
201
202
203
205
206
207
208
209
210
211
212
213
214 215
216
217
218
219
220
221
222
223
224
225
226 227
228
229
230
231
232
233
234
235
236
238
239
240
241
242
243
244
245
246
247
237
258
248
249
250
251
252
253
254
255
256
257
259
260
261
262
263
264
265
266
267
268 269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311 312

313
314
315
316
317
318
319
320
321
322
29
325
326
327
328
329
330
331
332
333
30 323 324
335
336
337
338
339
340
341
342
343
344
31 334FEXTR symbol

T1535350-00

NEXTR symbol

Figure I.19/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Downstream- 301 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

10

1

11

12

13

14

15

16

17

18

19

20

2

22

23

24

25

26

27

28

29

30

31

3 32
4 43
5

33

34

44

54

35

45

55

6

65

7 75
8 86

76

56

66

57

77
98

99

108

109

110

23
24

82

92

102

112

62

72

63

73

83

93

103

113

64

74

84

94

104

114

53

85

95

105

115

96
107

106

116

117

118

121

122

123

124

125

126

127

128

132

133

134

135

136

137

138

139

142

143

153

163

144

154

164

145

155

165

146

156

166

147

157

167

148

158

168

149

159

169

150
161

160

170

171

172

174

175

176

177

178

179

180

181

182

184

185

186

187

188

189

190

191

192

193
204

195

205

196

206

216

21 22622 239

81

91

101

111

61

71

42

52

173

17 18318 194
19
20

80

41

51

131
152

162

15
16

60

70

90

40

50

120

141

140
151

59

79
100

39

49

69

89

97

14

58

78

9

38

48

68

88

10

13

37

47

67

87

119
11
12 129 130

36

46

21

197

207

217

198

208

218

199

209

219

200

210

220

201

211

221

202

212

222

203

213

223

215

214

224

225

227

228

229

230

231

232

233

234

235

236

238

239

240

241

242

243

244

245

246

247
258

248

249

259

250

260

251

261

252

262

253

263

254

264

255

265

256

266

257

267

268

269

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
26 280
292
293
294
295
296
297
298
299
300
301
27 291
28
302
303
304
305
306
307
308
309
310
311
312
25

29
30 32331 334

313

314

324
335

315

325
336

316

326
337

317

327

318

328

338

339

319

329
340

320

330
341

321

331
342

322

332
343

333
344
T1535360-00

FEXTC symbol
NEXTC symbol

Figure I.20/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Upstream
I.7.2

Handshake – Non-standard information block (new)This section defines the format of the G.994.1 non-standard information block to support Annex I-EU, and tabulates theparameters used by Annex I-EU. The use of these parameters is described in §I.7.3 and §I.7.4.

I.7.2.1

Non-standard information block format (new)Figure I.21 defines the format of the non-standard information block.

- 302 -

8

7

6

5

4

3

2

1

Non-standard information length = M + 6(1 octet)
T.35 country code
(2 octets – see Note 1)
Provider code (vendor identification)(4 octets – see Note 2)
Vendor-specific information(M octets – Note 3)
NOTE 1 – The value of this field shall be B5 00, the country code for USA
NOTE 2 – The value of this field shall be 43 45 4E 54, ASCII “CENT” for Centillium
Communications
NOTE 3 – These octets are defined in §I.7.2.2. Formatting of these octets shall comply with theparsing rules defined in G.994.1 §9.2.1 to §9.2.3

Figure I.21 – Non-standard information block format

I.7.2.2

Non-standard information block parameters (new)The G.994.1 non-standard parameters for Annex I-EU are listed in Tables I.6 to I.7.4.2 below.
In order to minimize message length, the parameters for additional inband spectral shaping (Spar(2) octet and its related
Npar(3) octets) shall only be included in MP or MS messages, and shall not be included in CLR or CL messages. All
Annex I-EU modems shall support additional inband spectral shaping.
Note - This deviates from the rules specified in G.994.1 for standard information fields, where it isstated in §9.6:“Once a Transaction C (see 10.1) has been completed, any subsequent MS message
within the same G.994.1 session shall only contain those octets of the identification (I)and standard information (S) fields, and those blocks of non-standard information (NS)that were contained in both the CLR and CL messages of the previous Transaction C”.

Table I.6 – Non-standard information field – NPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Reserved for future use

x

x

x

x

x

x

1

x

Reserved for future use

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet- 303 -

NPar(1)sTable I.7 – Non-standard information field – SPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

G.992.1 Annex Q (and Annex Q-EU)

x

x

x

x

x

x

1

x

G.992.1 Annex I-EU

x

x

x

x

x

1

x

x

G.992.1 Annex C-EU

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet

SPar(1)sTable I.7.3 – Non-standard information field – G.992.1 Annex I-EU NPar(2) coding – Octet 1
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

nC-PILOT1 = 64

x

x

x

x

x

x

1

x

nC-PILOT1 = 128

x

x

x

x

x

1

x

x

nC-PILOT1 = 256

x

x

x

x

1

x

x

x

Amateur radio notch – 1.8 MHz band

x

x

x

1

x

x

x

x

Reserved for future use

G.992.1 Annex I-EU NPar(2)s

x

x

1

x

x

x

x

x

nC-PILOT1 = 96

x

x

0

0

0

0

0

0

No parameters in this octet

Since A48 is the only TTR indication signal specified for Annex I-EU, there is no need to include it in G.994.1.

Table I.7.3.1 – Non-standard information field – G.992.1 Annex I-EU NPar(2) coding – Octet
2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

R-ACK1

x

x

x

x

x

x

1

x

R-ACK2

G.992.1 Annex I-EU NPar(2)s – Octet 2

x

x

x

x

x

1

x

x

DBM

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

G.997.1 – Clear EOC OAM

x

x

0

0

0

0

0

0

No parameters in this octet

Since Annex I-EU only supports ATM transport, STM and ATM parameters are not specified.

- 304 -

Table I.7.4 – Non-standard information field – G.992.1 Annex I-EU SPar(2) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Additional inband spectral shaping

x

x

x

x

x

x

1

x

Extended upstream

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex I-EU SPar(2)s

Table I.7.4.1 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 1
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 1
NOMINAL_PSD_lowband (bits 8 & 7)
Reserved for future use

Table I.7.4.1.1 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 2
NOMINAL_PSD_lowband (bits 6 to 1)

Table I.7.4.1.2 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 3
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 3
PSD level at 1622 kHz (bits 8 & 7)
Reserved for future use- 305 -

Table I.7.4.1.3 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 4
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 4
PSD level at 1622 kHz (bits 6 to 1)

Table I.7.4.1.4 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 5
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 5
PSD level at 2208 kHz (bits 8 & 7)
Reserved for future use

Table I.7.4.1.5 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 6
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 6
PSD level at 2208 kHz (bits 6 to 1)

Table I.7.4.2 – Non-standard information field – G.992.1 Annex I-EU Extended upstream
NPar(3) coding Octet 1
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Mode 1 upstream mask

x

x

x

x

x

x

1

x

Mode 2 upstream mask

x

x

x

x

x

1

x

x

Optional upstream masks for non-overlapped spectrum

x

x

x

x

1

x

x

x

EU-64

x

x

x

1

x

x

x

x

EU-32

x

x

1

x

x

x

x

x

EU-36

x

x

0

0

0

0

0

0

No parameters in this octet- 306 -

G.992.1 Annex I-EU Extended upstream NPar(3)sOctet 1

Table I.7.4.2.1 – Non-standard information field – G.992.1 Annex I-EU Extended upstream
NPar(3) coding Octet 2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

EU-40

x

x

x

x

x

x

1

x

EU-44

x

x

x

x

x

1

x

x

EU-48

x

x

x

x

1

x

x

x

EU-52

x

x

x

1

x

x

x

x

EU-56

x

x

1

x

x

x

x

x

EU-60

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex I-EU Extended upstream NPar(3)sOctet 2

I.7.3

Handshake – Parameter definitions (supplements 10.2)

I.7.3.1

Handshake – ATU-C (supplements 10.2)

I.7.3.1.1

CL messages (supplements 10.2.1)

See Table I.8.

- 307 -

Table I.8/G.992.1 – ATU-C CL message NPar(2) bit definitions for Annex I-EU
NSF parameter
DBM

Definition
If set to ZERO, this bit shall indicate Bitmap-NR and Bitmap-NC are enabled (Dual Bitmapmode) and are used to transmit data. If set to ONE, this bit shall indicate Bitmap-NR andBitmap-NC are disabled (FEXT Bitmap mode), i.e. only Bitmap-FR and Bitmap-FC areused to transmit data by ATU-C and ATU-R respectively. This mode selection shall be only
performed by the ATU-C. If it is set to ONE in a CL message, it must be set to ONE in
subsequent MS messages from either the ATU-C or ATU-R.

G.992.1 Annex I-EU

If set to ONE, this Spar(1) bit indicates that the ATU-C is configured to support G.992.1
Annex I-EU.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission ofpilot tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission ofpilot tone on subcarrier 96.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission ofpilot tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission ofpilot tone on subcarrier 256.
If set to ONE, this Npar(2) bit indicates that the ATU-C is configured to reduce its transmit
power between 1.81 and 2.0 MHz to ≤ –80 dBm.
If set to ONE, this Spar(2) bit indicates that the ATU-C is configured to support extended
upstream.
If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-C supports. For non-overlapped spectrum, extended
upstream masks are associated with downstream masks according to Figure I.13. For
overlapped spectrum, any EU-xx may be used with the overlapped downstream spectrum
specified in §I.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support theoptional upstream masks when using non-overlapped spectrum downstream.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum

I.7.3.1.2

MS messages (supplements 10.2.2)

See Table I.9.

- 308 -

Table I.9/G.992.1 – ATU-C MS message NPar(2) bit definitions for Annex I-EU
NSF parameter
DBM

Definition
If set to ZERO, this bit shall indicate Bitmap-NR and Bitmap-NC are enabled (Dual
Bitmap mode) and are used to transmit data. If set to ONE, this bit shall indicate
Bitmap-NR and Bitmap-NC are disabled (FEXT Bitmap mode), i.e. only Bitmap-FR andBitmap-FC are used to transmit data by ATU-C and ATU-R respectively. This mode
selection shall be only performed by ATU-C. This bit shall be set to ONE if it was set to
ONE in a previous CL message.

G.992.1 Annex I-EU
nC-PILOT1=64

If set to ONE, this Spar(1) bit indicates that the ATU-C is selecting G.992.1 Annex I-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 256 (Note 1).
If set to ONE, this Npar(2) bit indicates that the ATU-C shall reduce its transmit power
between 1.81 and 2.0 MHz to ≤ –80 dBm.
If set to ONE, this Spar(2) bit indicates that the ATU-C shall apply additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD levelat 1622 kHz, and PSD level at 2208 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply in the passband below 1104 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply at 2208 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 2208 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-C is selecting extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-C is selecting upstream PSD mask
US-xx. For non-overlapped spectrum, extended upstream masks are associated withdownstream masks according to Figure I.13. For overlapped spectrum, any EU-xx may be
used with the overlapped downstream spectrum specified in §I.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 1(different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 2(same mask during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch –1.8 MHz band
Additional inband
spectral shaping
REDUCED_PSD_low
band
PSD level at 1622 kHz

PSD level at 2208 kHz

Extended upstream
EU-xx

Mode 1 upstream mask
Mode 2 upstream mask

Optional upstream
masks for nonoverlapped spectrum
Note 1: One and only one pilot tone bit shall be set in an MS message.
Note 2: One and only one upstream mask mode bit shall be set in an MS message.

I.7.3.2

Handshake – ATU-R (supplements 10.3)- 309 -

I.7.3.2.1

CLR messages (supplements 10.3.1)

See Table I.10.

- 310 -

Table I.10/G.992.1 – ATU-R CLR message NPar(2) bit definitions for Annex I-EU
NSF parameter
DBM

G.992.1 Annex I-EU
nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum

I.7.3.2.2

Definition
This bit shall be set to ONE.

If set to ONE, this Spar(1) bit indicates that the ATU-R is configured to support G.992.1
Annex I-EU.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 96.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 256.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports the 1.8 MHz
Amateur radio band notch.
If set to ONE, this Spar(2) bit indicates that the ATU-R is configured to support extended
upstream.
If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-R supports. For non-overlapped spectrum, extended upstream
masks are associated with downstream masks according to Figure I.13. For overlapped
spectrum, any EU-xx may be used with the overlapped downstream spectrum specified in§I.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support the optional
upstream masks when using non-overlapped spectrum downstream.

MS messages (supplements 10.3.2)

Table I.11.

Table I.11/G.992.1 – ATU-R MS message NPar(2) bit definitions for Annex I-EU
NSF parameter
DBM

Definition
If set to ZERO, this bit shall indicate Bitmap-NR and Bitmap-NC are enabled (Dual
Bitmap mode) and are used to transmit data. If set to ONE, this bit shall indicate
Bitmap-NR and Bitmap-NC are disabled (FEXT Bitmap mode), i.e. only Bitmap-FR andBitmap-FC are used to transmit data by ATU-C and ATU-R respectively. This mode
selection shall be only performed by ATU-C. This bit shall be set to ONE if it was set to
ONE in a previous CL message.

G.992.1 Annex I-EU
nC-PILOT1=64

If set to ONE, this Spar(1) bit indicates that the ATU-R is selecting G.992.1 Annex I-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 96 (Note 1).

nC-PILOT1=96- 311 -

nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Additional inband
spectral shaping
REDUCED_PSD_lo
wband
PSD level at 1622
kHz

PSD level at 2208
kHz

Extended upstream
EU-xx

If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shalleither be set to the same value as in a previous CL message or set to ONE.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting additional
downstream inband spectral shaping as defined by the values of
REDUCED_PSD_lowband, PSD level at 1622 kHz, and PSD level at 2208 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATUR wishes to have applied in the passband below 1104 kHz. It is coded in steps of
0.125dB relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000
means –40 dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATUR wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622
kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATUR wishes to have applied at 2208 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 2208 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-R is selecting upstream PSD mask
US-xx. For non-overlapped spectrum, extended upstream masks are associated used withdownstream masks according to Figure I.13. For overlapped spectrum, any EU-xx may
be used with the overlapped downstream spectrum specified in §I.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode
1 (different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode
2 (same mask during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum
Note 1: One and only one pilot tone bit shall be set in an MS message.
Note 2: One and only one upstream mask mode bit shall be set in an MS message.

I.7.3.2.3

MP messages (new)Table I.12.
Table I.12/G.992.1 – ATU-R MP message NPar(2) bit definitions for Annex I-EU
NSF parameter
R-ACK1
R-ACK2
G.992.1 Annex I-EU
nC-PILOT1=64
nC-PILOT1=96

Definition
Proposes that the ATU-C send C-PILOT1A, C-QUIET3A, C-PILOT2 and C-QUIET5 duringtransceiver training.
Proposes that the ATU-C send C-PILOT1, C-PILOT2 and C-PILOT3 during transceivertraining.
If set to ONE, this Spar(1) bit indicates that the ATU-R is proposing G.992.1 Annex I-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is proposing the pilot tone on
subcarrier 96 (Note 1).

- 312 -

nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Additional inband
spectral shaping
REDUCED_PSD_lo
wband
PSD level at 1622
kHz

PSD level at 2208
kHz

Extended upstream
EU-xx

If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 2208 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 2208 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 2208 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-R is proposing upstream PSD mask
US-xx. For non-overlapped spectrum, extended upstream masks are associated withdownstream masks according to Figure I.13. For overlapped spectrum, any EU-xx may be
used with the overlapped downstream spectrum specified in §I.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode 1(different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode 2(same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing one of the optional
upstream masks when using non-overlapped spectrum downstream.

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum
Note 1: More than one pilot tone bit may be set in an MP message.

I.7.4

Transceiver Training – ATU-C (supplements 10.4)

During transceiver training from C-REVERB1 to C-SEGUE1 except C-PILOTn and C-QUIETn, the ATU-C shalltransmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), and shall not transmit
the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state isdefined as Figure I.26.
I.7.4.1

C-PILOT1 (supplements 10.4.2)

The ATU-C shall start the NSWF (sliding window frame) counter from 0 immediately after entering C-PILOT1, andincrement the NSWF counter modulo 345 after transmission of each DMT symbol. According to the sliding windowfunction and this counter, the ATU-C decides to transmit all of the subsequent symbols in either FEXTR or NEXTR
symbols (for example, see Figures I.11, I.19 and I.24).
C-PILOT1 has two signals.
The first signal is the pilot tone, a single frequency sinusoid at fC-PILOT1 defined as:- 313 -

⎧
Xk = ⎨⎩

0, k ≠ nC − PILOT 1 , 0 ≤ k ≤ NSC
AC − PILOT 1 , k = nC − PILOT 1

The frequency of the pilot tone shall be selected from one of the following choices during G.994.1 as:
16. fC-PILOT1 = 276 kHz (nC-PILOT1 = 64).
17. fC-PILOT1 = 414 kHz (nC-PILOT1 = 96).
18. fC-PILOT1 = 552 kHz (nC-PILOT1 = 128).
19. fC-PILOT1 = 1104 kHz (nC-PILOT1 = 256).
Transmitters that support Annex I-EU shall support all of these pilot tones.
The second signal is the TTR indication signal used to transmit NEXTR/FEXTR information. The ATU-R can detect
the phase information of the TTRC from this signal. The TTR indication signal shall be selected during G.994.1 as:
A48 signal –the constellation encoding of the 48th carrier with 2-bit constellation as follows:(+ , +) to indicate a FEXTR symbol;(+ , –) to indicate a NEXTR symbol.
I.7.4.2

C-PILOT1A (supplements 10.4.3)

C-PILOT1A has two signals and it is the same transmitted signal as C-PILOT1 (C.7.4.1).
I.7.4.3

C-REVERB3 (supplements 10.4.11)

In order to synchronize the first symbol of C-RATES1 with the beginning of the hyperframe and to inform the enteringtiming of C-RATES1 to the ATU-R, the first symbol of C-SEGUE1 shall be transmitted inside of the FEXTR duration
as shown in Figure I.22. Therefore, the duration of C-REVERB3 is 3628 DMT symbols.

TTRC
20 symbols
C-SEGUE1

C-REVERB3

C-RATES1

the time of the detection
C-SEGUE1

R-REVERB3
T1532880-99

Figure I.22/G.992.1 – Timing diagram from C-SEGUE1 to C-RATES1

I.7.4.4

C-REVERB1 (replaces 10.4.5)

C-REVERB1 is a signal that allows the ATU-C and ATU-R receiver to adjust its automatic gain control (AGC) to an
appropriate level. The data pattern used in C-REVERB1 shall be the pseudo-random downstream sequence (PRD), dn
for n = 1 to 2*NSCds, defined in I.4.7.5 and repeated here for convenience:dn = 1dn = dn-4 ⊕ dn-9

for n = 1 to 9
for n = 10 to 2*NSCds- 314 -

(10-1)

The bits shall be used as follows: the first pair of bits (d1 and d2) is used for the DC and Nyquist subcarriers (the powerassigned to them is, of course, zero, so the bits are effectively ignored); then the first and second bits of subsequentpairs are used to define the Xi and Yi for i = 1 to NSCds-1 as defined in Table 7-13.
The period of PRD is only 511 bits, so dn+511 is equal to dn. The bits d1 to d9 shall be re-initialized for each symbol,
so each symbol of C-REVERB1 is identical.
The two bits that modulate the pilot carrier shall be overwritten by {0,0}: generating the {+,+} constellation.
The duration of C-REVERB1 is 512 (repeating) symbols without cyclic prefix.
I.7.4.4.1

Power Cut-back (supplements 10.4.5.1)

For Annex I-EU, see A.3.1.

I.7.5

Transceiver Training – ATU-R (supplements 10.5)

During transceiver training from R-REVERB1 to R-SEGUE1 except R-QUIETn, the ATU-R shall transmit both
FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC
symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is defined as Figure I.26.
I.7.5.1

R-QUIET2 (supplements 10.5.1)

The ATU-R enters R-REVERB1 after it completes timing recovery and Hyperframe synchronization from
C-PILOT1/C-PILOT1A.
I.7.5.2

R-REVERB1 (supplements 10.5.2)

The data pattern used in R-REVERB1 is the pseudo-random upstream sequence PRU defined in 8.11.3, repeated asnecessary for the selected NSCus:⎧⎪d n = 1⎨⎪⎩d n = d n −5

for n = 1 to 6
⊕ d n − 6 for n = 7 to 64(C.10-1)

The period of PRU is only 63 bits, so dn+63 is equal to dn.
The ATU-R shall start its NSWF counter immediately after entering R-REVERB1, and then increment the NSWF
counter with modulo 345 from 0 when it transmits each DMT symbol. The ATU-C and ATU-R shall have the samevalue since hyperframe alignment between the ATU-C and ATU-R shall be maintained. According to the sliding
window and this counter, the ATU-R decides to transmit all of the subsequent symbols in either the FEXTC or the
NEXTC symbol.
I.7.5.3

R-QUIET3 (replaces 10.5.3)

The final symbol of R-QUIET3 accommodates the frame alignment of the transmitter to that of the receiver. It may be
shortened by any number of samples. The maximum duration of R-QUIET3 is 6145 DMT symbols.
I.7.5.4

R-REVERB2 (supplements 10.5.5)

After ATU-R detects C-SEGUE1, the ATU-R enters R-SEGUE1. The maximum duration of R-REVERB2 is 3643
DMT symbols.
I.7.6

Channel analysis (ATU-C) (supplements 10.6)

ATU-C shall transmit only FEXTR symbols, and shall not transmit the NEXTR symbols except the pilot tone from- 315 -

C-RATES1 to C-CRC2. During C-MEDLEY, the ATU-C shall transmit both FEXTR and NEXTR symbols when
Bitmap-NR is enabled (Dual Bitmap mode). The ATU-C shall not transmit NEXTR symbols except the pilot tone,
when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state is defined in Figure I.26.
I.7.6.1

C-SEGUE1 (supplements 10.6.1)

The duration of C-SEGUE1 is 20 symbols in order that the first symbol of C-SEGUE1 shall be inside of the FEXTR
duration.

- 316 -

I.7.6.2

C-MEDLEY (replaces 10.6.6)

C-MEDLEY is a wideband pseudo-random signal used for estimation at the ATU-R of the downstream SNR. The data
to be transmitted are derived from the pseudo-random sequence, PRDm, defined as:
d n = 1 for n = 1 to 14 and d n = d n-5 ⊕ d n-11 ⊕ d n-12 ⊕ d n-14 for n> 14,
and modulated as defined in 10.4.5. In contrast to C-REVERB1, the cyclic prefix is used and the data sequence
continues from one symbol to the next (i.e. d1 to d14 are not re-initialized for each symbol). Because the sequence is oflength 214-1, and far fewer bits are used for each symbol, the subcarrier vector for C-MEDLEY changes from one
symbol period to the next. For non-overlapped spectrum, 2*(512-mm+1) bits are used each symbol, where mm is theminimum subcarrier specified for PSD mask DS-mm in Table I.13. For overlapped spectrum, 2*507 bits are used eachsymbol. The pilot subcarrier is overwritten by the (+,+) signal constellation. The duration of C-MEDLEY is as shown in
Figure I.26. Following C-MEDLEY the ATU-C shall enter the state C-REVERB4.
With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure I.23. The ATU-C
transmits the signal in both of NEXTR and FEXTR symbols, and the ATU-R estimates two SNRs from the received
NEXTR and FEXTR symbols, respectively, as defined in Figure I.24.
The following formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > d) }if { (S > b) and (S + 271 < c) }where a = 1243, b = 1403, c = 2613, d = 2704

then symbol for estimation of FEXTR SNR
then symbol for estimation of NEXTR SNR

When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbol. The
number of bits of NEXTR shall be no more than the number of bits of FEXTR.
At the transmitter, the PRDm sequence generator shall continue to be updated during NEXTR symbols when BitmapNR is disabled (FEXT Bitmap mode).

- 317 -TTR
TCM-ISDN crosstalkat ATU-R receiver

TCM-ISDN crosstalkat ATU-C receiver

NEXT

NEXT

FEXT

FEXT

FEXT

NEXT

NEXT

NEXT

FEXT

FEXT
Estimation of
Signal-to-Noise ratio

C/R-MEDLEY (49152 symbols)

Bitmap for Downstream

Bitmap-NR

Bitmap-FR

Bitmap-FR

Bitmap-NR

Bitmap for Upstream

Bitmap-FC

Bitmap-NC

Bitmap-NC

Bitmap-FC
T1532890-99

Figure I.23/G.992.1 – Estimation of periodic Signal-to-Noise Ratio- 318 -

TTRC
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

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2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

41

42

43

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47

48

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4
5

51

52

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55

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57

58

59

60

6

61

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63

64

65

66

67

68

69

70

7

71

72

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75

76

77

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8

81

82

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84

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88

89

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9

91

92

93

94

95

96

97

98

99

100

101

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

137

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

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159

160

161

16

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

17
18

183

184

185

186

187

188

189

190

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192

19

193

194

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196

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25

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26

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265

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286

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288

289

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29

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300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

315

316

317

318

319

320

321

322

323

324

31

314

32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

Symbol for estimation of FEXTR S/N
Symbol for estimation of NEXTR S/N

Symbol not used for S/N estimation
T1535370-00

Figure I.24/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Downstream

I.7.6.3

C-RATES1 (supplements 10.6.2)

In order to support data rates greater than 16 Mbit/s, the BI field has 10 bits. The RRSI fields shall use the same
extended syntax as defined in I.7.9.4 for C-RATES-RA.
For the S=1/2n framing mode (see §I.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,- 319 -RSI = RI/(n*S).
I.7.6.4

C-MSG1 (supplements 10.6.4)

Table I.13/G.992.1 – Assignment of 48 bits of C-MSG1
Suffix(ces) of mi (Note 1)
Parameter (Note 3)
47-44
Minimum required downstream SNR margin at initialization (Note 2)
43-18
Reserved for future use
17
Trellis coding option
16
Overlapped spectrum option (Note 4)
15
Unused (shall be set to "1")
14-12
Reserved for future use
11
NTR
10-9
Framing mode
8-6
Transmit PSD during initialization
5
Reserved
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – A positive number of dB; binary coded 0-15 dB.
NOTE 3 – All reserved bits shall be set to "0".
NOTE 4 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
I.7.6.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.6.4.8)

The Ndownmax (transmit) capability shall be binary encoded onto {m4, ..., m0} (e.g. 100012 = 17). The maximum
number of bits for the upstream data, Nupmax, that the ATU-C receiver can support need not be signalled to the ATU-R;
it will be implicit in the bits and gains message, C-B&G, which is transmitted after channel analysis.
I.7.7

Channel analysis (ATU-R) (supplements 10.7)

From R-RATES1 to R-CRC2, the ATU-R shall transmit only the FEXTC symbols and shall not transmit the NEXTC
symbols. In R-SEGUE2 and R-MEDLEY, the ATU-R shall transmit both FEXTC and NEXTC symbols when
Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC symbols when Bitmap-NC is disabled(FEXT Bitmap mode). The duration of each state is defined in Figure I.26.
I.7.8

R-SEGUE1 (supplements 10.7.1)

The maximum duration of R-SEGUE1 is 14 symbols (see Figure I.22).
I.7.8.1

R-REVERB3 (supplements 10.7.2)

The ATU-R shall start R-REVERB3 aligned with the beginning of a Hyperframe.
I.7.8.2

R-SEGUE2 (supplements 10.7.3)

The duration of R-SEGUE2 is 13 symbols.
I.7.8.3

R-MEDLEY (replaces 10.7.8)

R-MEDLEY is a wideband pseudo-random signal used for estimation of the upstream SNR at the ATU-C. The data to
be transmitted are derived from the pseudo-random sequence PRUm defined as:
d n = 1 for n = 1 to 23 and d n = d n-18 ⊕ d n-23 for n> 23.
In contrast to R-REVERB1, the cyclic prefix is used and the data sequence continues from one symbol to the next (i.e.
d1 to d23 are not re-initialized for each symbol). Because the sequence is of length 223-1, and 2*(nn-5) bits are used for- 320 -

each symbol (where nn is the maximum subcarrier specified for PSD mask EU-nn in Table I.18), the subcarrier vector
for R-MEDLEY changes from one symbol period to the next. Following R-MEDLEY the ATU-R enters signalling state
R-REVERB4. The duration of R-MEDLEY is as shown in Figure I.26.
With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure I.23. ATU-R shalltransmit the signal in both of NEXTC and FEXTC symbols, and ATU-C shall estimate two SNRs from the received
NEXTC and FEXTC symbols, respectively, as defined in Figure I.25.
The following numerical formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > b) and (S + 271 < c) }if { (S + 271 < a) }where a = 1148, b = 1315, c = 2608

then symbol for estimation of FEXTC SNR
then symbol for estimation of NEXTC SNRWhen Bitmap-NC is disabled (FEXT Bitmap mode), the ATU-R shall not transmit NEXTC symbol. The number of bitsof NEXTC shall be no more than the number of bits of FEXTC.
At the transmitter, the PRUm sequence generator shall continue to be updated during NEXTC symbols when BitmapNC is disabled (FEXT Bitmap mode).

- 321 -

TTR R
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

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25

26

27

28

29

3

30

31

32

33

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4

41

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48

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50

5

51

52

53

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55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

101

10

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

11
12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

137

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

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159

160

161

16

162

163

164

165

166

167

168

169

170

171

172

17

173

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177

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179

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18

183

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203

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207

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209

210

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212

21

213

214

215

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219

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221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

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237

238

239

240

241

242

243

24

244

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246

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248

249

250

251

252

253

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

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270

271

272

273

27

274

275

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

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293

29

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295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

T1535290-00

Symbol for estimation of FEXT C S/N

Symbol not used for S/N estimation

Symbol for estimation of NEXT C S/N

Figure I.25/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Upstream

I.7.8.4

R-MSG1 (supplements 10.7.6)- 322 -

Table I.14/G.992.1 – Assignment of 48 bits of R-MSG1
Parameter (Note 2)
Suffix(ces) of mi (Note 1)
47-18
Reserved for future use

17
Trellis coding option
16
Overlapped spectrum option (Note 3)
15
Unused (shall be set to "1")14
Support of S = 1/2 mode (see I.4.9) (Note 4)
13
Support of dual latency downstream
12
Support of dual latency upstream
11
Network Timing Reference
10, 9
Framing mode
8-5
Reserved for future use
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
NOTE 3 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
NOTE 4 – Since the S=1/2 mode is mandatory for Annex I-EU, a modem supporting Annex I-EU shall set this bit tobinary ONE.

I.7.8.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.7.6.6)

The Nupmax (transmit) capability is encoded onto {m4 , ..., m0} with a conventional binary representation (e.g.
100012 = 17).
I.7.9

Exchange – ATU-C (supplements 10.8)

During C-RATESn, C-MSGn, C-B&G, and C-CRCn, the ATU-C shall transmit the FEXTR symbol. In the other signals,
the ATU-C shall transmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), andshall not transmit the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The
duration of each state is defined in Figure I.27.
I.7.9.1
C-MSG2 (supplements 10.8.9)
Replace Table 10-13 with Table I.15.

Table I.15/G.992.1 – Assignment of 32 bits of C-MSG2
Suffix(ces) of mi (Note 1)

Parameter (Note 2)

31-26

Estimated average loop attenuation

25-21

Reserved for future use

20-16

Performance margin with selected rate option

15-11

Reserved for future use

10-0

Total number of bits supported

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
For NSCus=32,
n1C-MSG2 = 43
n2C-MSG2 = 91

- 323 -

Otherwise,
n1C-MSG2 = 139
n2C-MSG2 = 187
I.7.9.1.1

Total number of bits per symbol supported (replaces 10.8.9.3)

The ATU-C receiver shall also calculate the maximum number of bits per symbol that the upstream channel can support−7

with the performance margin defined in C-MSG-RA at an error rate of 10 .
The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTC and
NEXTC downstream channel performance [e.g. if the maximum numbers of bits that can be supported in FEXTC and
NEXTC symbols are 111 and 88 {Total number of bits per symbol supported} = (111 x 126 + 88 x 214)/340 = 96]. This
number is encoded into bits 10-0 using a conventional binary representation [e.g. if the maximum number of bits thatcan be supported is 96 (data rate = 384 kbit/s), {m10, ..., m0} = 000011111112].
NOTE – The number of symbols per hyperframe is 340. The number of FEXT symbols is 126. The number of NEXTsymbols is 214.
I.7.9.1.2

Estimated average upstream loop attenuation (supplements 10.8.9.1)

For Annex I-EU, see A.3.2.

I.7.9.2

C-B&G (replaces 10.8.13)

C-B&G shall be used to transmit to the ATU-R the bits and gains information, Bitmap-FC {b1, g1, b2, g2, ... bNSCus-1,
gNSCus-1}, and Bitmap-NC {b NSCus+1, g NSCus+1, b NSCus+2, g NSCus+2, ..., b2*NSCus-1, g2*NSCus-1}, thatare to be used on the upstream carriers. bi of Bitmap-FC indicates the number of bits to be coded by ATU-R transmitter
onto the i th upstream carrier in FEXTC symbols; gi of Bitmap-FC indicates the scale factor, relative to the gain thatwas used for that carrier during the transmission of R-MEDLEY, that shall be applied to the i th upstream carrier in
FEXTC symbols. Similarly, bi of Bitmap-NC indicates the number of bits onto the (i – NSCus) th upstream carrier in
NEXTC symbols; gi of Bitmap-NC indicates the scale factor that shall be applied to the (i – NSCus) th upstream carrierin NEXTC symbols.
Because no bits or energy will be transmitted at DC or one-half the sampling rate, b0, g0, bNSCus, gNSCus, b2*NSCus,
and g2*NSCus are all presumed to be zero and shall not be transmitted.
Each bi shall be represented as an unsigned 5-bit integer, with valid bis lying in the range of zero to Nupmax, themaximum number of bits that the ATU-R is prepared to modulate onto any subcarrier, which is communicated in
R-MSG1.
Each gi shall be represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of
the third most significant bit. For example, a gi with binary representation (most significant bit listed first)
001.010000002 would instruct the ATU-R to scale the constellation for carrier i, by a gain factor of 1.25, so that thepower in that carrier shall be 1.94 dB higher than it was during R-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
Let NSCu=128, except when EU-32 is used where NSCu=32. The C-B&G information shall be mapped in a32*(NSCu-1)-bit (4*(NSCu-1) byte) message m defined by:- 324 -

m = {m32*(NSCu-1)-1, m32*(NSCu-1)-2, …, m1, m0} = { g2*NSCu-1, b2*NSCu-1, …, g NSCu+1, b NSCu+1, g(C.10-2)
NSCu-1, b NSCu-1, …, g1, b1},
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in
4*(NSCu-1) FEXTR symbols. When NSCu=32, including C_CRC5, the total length is 336 symbols while for
NSCu=128, the total length is 336+3*345=1371 symbols, using the transmission method as described in 10.8.9.
When Bitmap-NC is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NC shall be set to zero.
For index between NSCus+1 and 127, the m values are set to 0.

I.7.9.3

C-SEGUE3 (replaces 10.8.16)

The duration of C-SEGUE3 is 18 symbols. Following C-SEGUE3, the ATU-C completes the initialization and enters
C-SHOWTIME. In C-SHOWTIME, ATU-C shall transmit the signal using Bitmap-FR and Bitmap-NR with the sliding
window.
When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbols.
I.7.9.4

C-RATES-RA (supplements 10.8.3)
Table I.16/G.992.1 – RRSI fields of C-RATES-RA←⎯⎯⎯⎯⎯ bits ⎯⎯⎯⎯→
fields

7

6

RSF

0

0

5

4

3

2

1

value of RSF
MSB

RSI

B8 (AS0)LSB

B9 (AS0)

value of RSI
MSB

S

I9

LSB

I8

value of S
MSBIFS(LS2)

I7

I6

0

I5

LSB
I4

I3

I2

I1

I0

value of FS(LS2) set to {000000002}

The RSI field has been extended to include the most significant bit B9 of BI (AS0), the number of payload bytes in theAS0 bearer channel in the downstream interleave buffer, in bit 6. This is to support the higher data rates for the optional
S=1/4 and S=1/3 modes.
The S field shall be coded {1001002) to indicate S=1/4.
For the S=1/2n framing mode (see §I.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).

- 325 -

I.7.10

Exchange – ATU-R (supplements 10.9)

ATU-R shall transmit only the FEXTC symbols in R-MSGn, R-RATESn, R-B&G, R-CRCn. In other signals, the
ATU-R shall transmit both FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shallnot transmit NEXTC symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is definedin Figure I.27.
I.7.10.1

R-MSG-RA (supplements 10.9.2)

Replace Table 10-15 with Table I.17.

Table I.17/G.992.1 – Assignment of 80 bits of R-MSG-RA (Annex I-EU)
Suffix(ces) of mi(Note)
79-71
70
69, 68
67-56

Parameter
All reserved bits shall be set to 0
Reserved for ITU-T
Extension to number of RS payload bytes, K
Extension to number of tones carrying data (ncloaded)
Bfast-max

55-49
48-40
39-32
31-25
24-21
20-16
15
14

Number of RS overhead bytes, (R)
Number of RS payload bytes, K
Number of tones carrying data (ncloaded)
Estimated average loop attenuation
Coding gain
Performance margin with selected rate option
Reserved for ITU-T
Extension to total number of bits per DMT symbol, Bmax

13-12
11-0

Maximum Interleave Depth downstream
Total number of bits per DMT symbol, Bmax

NOTE – Within the separate fields the least significant bits have the lowest subscripts.

I.7.10.1.1

Total number of bits supported (Bmax) (replaces 10.9.2.8)

This parameter shall be defined as in R-MSG2, see I.7.9.1.
I.7.10.1.2

Bfast-max (new)Bfast-max is the maximum number of bits of the fast buffer for fast data transmitted on the condition that the bits of thefast data can be equally assigned to all FEXT-symbols and NEXT-symbols.
Fast Buffered Data Bfast-max is tf.
I.7.10.2

R-MSG2 ( supplements 10.9.8)- 326 -

Suffix(ces) of mi (Note 1)
31-25
24-21
20-16
15
14
13-12
11-0

Table I.18/G.992.1 – Assignment of 32 bits of R-MSG2
Parameter (Note 2)
Estimated average loop attenuation
Reserved for future use
Performance margin with selected rate option
Reserved for future use
Extension to total number of bits per DMT symbol, Bmax
Reserved for future use
Total number of bits per DMT symbol, Bmax

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
N1R-MSG2 = 10
N2R-MSG2 = 20
I.7.10.2.1

Total number of bits per symbol supported (supplements 10.9.8.3)

The maximum number of bits per symbol that the downstream channel can support is encoded into bits 14 and 11 – 0.
The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTR and
NEXTR downstream channel performance. For example, if the maximum numbers of bits that can be supported in
FEXTR and NEXTR symbols are 111 and 88, the total number of bits per symbol supported is (111 x 126 + 88 x
214)/340 = 96.
NOTE – The number of symbols per hyperframe is 340, the number of FEXT symbols is 126, and the number of NEXTsymbols is 214.
I.7.10.2.2

Estimated average downstream loop attenuation (supplements 10.9.8.1)

For Annex I-EU, see A.3.3.
I.7.10.3 R-REVERB5 (supplement of 10.9.12)
The duration of R-REVERB5 is 345n-40, 3<=n<=19, when NSCu=128, or 3<=n<=16 when NSCu=32.
I.7.10.4

R-B&G (replaces 10.9.14)

The purpose of R-B&G is to transmit to ATU-C the bits and gains information, Bitmap-FR {b1, g1, b2, g2, ...,bNSCds-1, gNSCds-1}, and Bitmap-NR {bNSCds+1, gNSCds+1, bNSCds+2, gNSCds+2, ..., b2*NSCds-1,
g2*NSCds-1}, to be used on the downstream subcarriers. bi of Bitmap-FR indicates the number of bits to be coded by
ATU-C transmitter onto the i th downstream subcarrier in FEXTR symbols; gi of Bitmap-FR indicates the scale factor
that shall be applied to the i th downstream subcarrier in FEXTR symbols, relative to the gain that was used for thatcarrier during the transmission of C-MEDLEY. Similarly, bi of Bitmap-NR indicates the number of bits onto the (i –NSCds) th downstream carrier in NEXTR symbols; gi of Bitmap-NR indicates the scale factor that shall be applied tothe (i – NSCds) th downstream carrier in NEXTR symbols. Because no bits or energy will be transmitted at DC or
one-half the sampling rate, b0, g0, bNSCds, gNSCds, b2*NSCds, and g2*NSCds are all presumed to be zero, and are
not transmitted. When subcarrier 64 is reserved as the pilot tone, b64 and bNSCds+64, shall be set to 0, g64 andgNSCds+64 shall be set to gsync. When subcarrier 128 is reserved as the pilot tone, b128 and bNSCds+128, shall be set
to 0, g128 and gNSCds+128 shall be set to gsync. When subcarrier 256 is reserved as the pilot tone, b256 andbNSCds+256, shall be set to 0, g256 and gNSCds+256 shall be set to gsync. The value gsync represents the gain scaling
applied to the sync symbol.
Each bi is represented as an unsigned 5-bit integer, with valid bi lying in the range of zero to Ndownmax, the maximum- 327 -

number of bits that the ATU-C is prepared to modulate onto any subcarrier, which is communicated in C-MSG1.
Each gi is represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of thethird most significant bit. For example, a gi with binary representation (most significant bit listed first) 001.010000002
would instruct the ATU-C to scale the constellation for carrier i by a gain factor of 1.25, so that the power in that carrier
shall be 1.94 dB higher than it was during C-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
The R-B&G information shall be mapped in a (2*NSCds-2)*16-bit ((2*NSCds-2)*2 byte) message m defined by:
m = {m(2*NSCds-2)*16-1, m(2*NSCds-2)*16-2, …, m1, m0} = { g2*NSCds-1, b2*NSCds-1, …, g NSCds+1, b(I.10-3)
NSCds+1, g NSCds-1, b NSCds-1, …, g1, b1},
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in(2*NSCds-2)*2 symbols, using the transmission method as described in 10.9.8.
When Bitmap-NR is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NR shall be set to zero.

- 328 -

I.7.10.5

R-SEGUE5 (replaces 10.9.17)

The duration of R-SEGUE5 is 13 symbols. Following R-SEGUE-5, ATU-R completes the initialization and enters
R-SHOWTIME. In R-SHOWTIME, ATU-R shall transmit the signal using Bitmap-FC and Bitmap-NC with the sliding
window.
When Bitmap-NC is disabled (FEXT Bitmap mode), ATU-R shall not transmit NEXTC symbols.
ATU-C
C-FLAG2(G.994.1)

C-GALF2(G.994.1)≥ 128≤ 2048C-QUIET2(Note 5)345n(n ≤ 38)

ATU-R

If R-ACK2then
C-PILOT1

If R-ACK1then
C-PILOT1AR-GALF2(G.994.1)

Beginning ofHyperframe

R-QUIET2≤ 15500

345n(1 ≤ n ≤ 33)≤ 32
Beginning ofHyperframe

1725

C-QUIET3A(Note 2)

R-FLAG2(G.994.1)

R-REVERB1
1536

C-REVERB1
12477(Note 5)9216

C-PILOT2(Note 4)

1536

C-ECT

(Note 2)

(Note 5)4608

C-REVERB2

1536

If R-ACK2 then C-PILOT3
If R-ACK1 then C-QUIET53628

C-REVERB3

20

C-SEGUE1

2884

C-RATES1/C-CRC1
C-MSG1/C-CRC2

Last symbol
may beshortened byn samples

R-QUIET3≥ 6144≤ 6145

R-ECT

1536

R-REVERB2≥ 3634≤ 3643

R-SEGUE1

5 ≤, ≤ 14(Note 2)

(Note 1)Introduction ofguard time

R-REVERB3
345n + 208(0 ≤ n ≤ 7)

49152
C-MEDLEY

345n - 13(9 ≤ n ≤ 16)
R-SEGUE2

13

R-RATES1/R-CRC1
R-MSG1/R-CRC2

1254

R-MEDLEY

49152(Note 3)(Note 2)

T1532900-99

Figure I.26/G.992.1 – Timing diagram of the initialization sequence – Part 1- 329 -

(Note 4)NOTE 1 – The ATU-C shall transmit the FEXTR symbols, and shall not transmit as NEXTR symbols except the pilot
tone.
NOTE 2 – The ATU-C shall transmit both FEXTR and NEXTR symbols, when Bitmap-NR is enabled (Dual Bitmapmode). ATU-C shall not transmit the NEXTR symbols except pilot tone, when Bitmap-NR is disabled(FEXT Bitmap mode).
NOTE 3 – The ATU-R shall transmit the FEXTC symbols, and shall not transmit the NEXTC symbols.
NOTE 4 – The ATU-R shall transmit both FEXTC symbols, when Bitmap-NC is enabled (Dual Bitmap mode).
ATU-R shall not transmit NEXTC symbols, when Bitmap-NC is disabled (FEXT Bitmap mode).

- 330 -NOTE 5 – The ATU-C shall transmit both FEXTR and NEXTR symbols.
Figure I.27/G.992.1 – Timing diagram of the initialization sequence – Part 2[Editor’s note: Need to update Figure I.27 to parameterize the length of C-B&G and the maximum length of RREVERB5.]
I.8
I.8.1.1

AOC On-line adaptation and reconfiguration (pertains to clause 11)
Bit swap request (replaces 11.2.3)

The receiver shall initiate a bit swap by sending a bit swap request to the transmitter via the AOC channel. This request
tells the transmitter which subcarriers are to be modified. The format of the request is shown in Table I.19.

Table I.19/G.992.1 – Format of the bit swap request message
Message header{111111112}(8 bits)

Bitmap index(1 bit)Message field 1-4
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

The request shall comprise nine bytes as follows:• an AOC message header consisting of 8 binary ones;• message fields 1-4, each of which consists of a one-bit bitmap index, subchannel index bits 10 & 9, and a five-bit
command followed by bits 8 to 1 of the subchannel index. One-bit bitmap index, subchannel index bits 10 & 9,
and valid five-bit commands for the bit swap message shall be as shown in Table I.20. In Table I.20, the MSB
for the bit swap request command represents the Bitmap index. For downstream data, Bitmap index equals 0
indicates Bitmap-FR, and Bitmap index equals 1 indicates Bitmap-NR. Similarly for upstream data, Bitmap
index equals 0 indicates Bitmap-FC, and 1 indicates Bitmap-NC. The next 2 bits are subchannel index bits 10 &9. The ten-bit subchannel index is counted from low to high frequencies with the lowest frequency subcarrier
having the number zero. The subcarrier index zero shall not be used;• the bit swap between FEXTC/R symbols and NEXTC/R symbols is not allowed.

- 331 -

Table I.20/G.992.1 – Bit swap request commandValue(8 bit)yzz000002

Interpretation
Do nothing

yzz000012
yzz000102

Increase the number of allocated bits by one

yzz000112
yzz001002

Increase the transmitted power by 1 dB

yzz001012
yzz001102

Increase the transmitted power by 3 dB

yzz001112
yzz01xxx2

Reduce the transmitted power by 2 dB

Decrease the number of allocated bits by one
Increase the transmitted power by 2 dB
Reduce the transmitted power by 1 dB
Reserved for vendor discretionary commands

NOTE – y is "0" for FEXTC/R symbols, and "1" for NEXTC/R symbols of the Sliding Window.
NOTE – subchannel index = zz2*256 + subchannel index value from lower 8 bit field
The bit swap request message (i.e. header and message fields) shall be transmitted five consecutive times.
To avoid gi divergence between ATU-C and ATU-R after several bit swaps, for a gi update of ∆ dB the new gi value
should be given by:

g i ' = (1 / 256) × round (256 × g i × 10 exp(∆ / 20))I.8.1.2(I.11-1)

Extended bit swap request (supplements 11.2.4)

The format of the extended bit swap request is shown in Table I.21.

Table I.21/G.992.1 – Format of the bit swap request message
Message header{111111002}(8 bits)

Bitmap index(1 bit)Message field 1-6
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

In the same manner as the bit swap request, each of the message fields of the extended bit swap request consists of
one-bit bitmap index, a five-bit command followed by a related ten-bit subchannel index.
I.8.1.3

Bit swap acknowledge (supplements 11.2.5)

The bit swap superframe counter number shall only indicate the last superframe (SPF#4) of a hyperframe.
The new bit and/or transmit power table(s) shall then take effect starting from the first frame (frame 0) of SPF#0 of a
hyperframe.
If the bit swap superframe counter number contained in the received bit swap acknowledge message does not indicate
SPF#4, then the new table(s) shall take effect starting from frame 0 of SPF#0 of the next hyperframe.
I.9

POTS splitter

For operation according to G.992.1 Annex I-EU, the Annex E.4/G.992.3 requirements applying over a frequency band
up to 1104 kHz, shall be met over a frequency band up to 2208 kHz.

- 332 -

資料６
G.992.1 ANNEX I-EU (REVISION 2.0)
PROPRIETARY EXTENSION TO G.992.1 ANNEX I

This document defines G.992.1 Annex I-EU (Double spectrum downstream with extended upstream spectrum), a
proprietary extension to G.992.1 Annex I to extend the data rate beyond 24Mbit/s upstream by way of:• Increase upstream bandwidth Æ increased number of subcarriers, NSCus=96• Increased bit loading, beyond 15 bits/bin
Due to the increase in upstream data rates, the upstream maximum interleave depth has been increased to 16. Support ofthis is mandatory.
The attached text is the approved text for Annex I, marked up with revision control to show the changes necessary tosupport the additional functionality.
Revision 2 text is based on G.992.1 Annex I-EU Revision 1.1, and supports the following features:• extended upstream to subcarrier 96. Added EU-S68 to EU-S96.
••••- 333 -

ANNEX I-EU
Specific requirements for an ADSL system to support upstream data rates greater than 4 Mbit/s with improved
performance on short loops operating in the same cable as ISDN as defined in ITU-T Recommendation G.961
Appendix III

I.1

Scope

This annex describes those specifications that are unique to an ADSL system coexisting in the same binder as
TCM-ISDN as defined Recommendation G.961 Appendix III. The subclauses in this annex provide supplementary andreplacement material to the clauses in the main body. The nature of the material is parenthetically indicated in the
subclause heading. The modifications described in this annex allow a performance improvement from the ADSL system
specified in Annex C for short loops in an environment coexisting with TCM-ISDN in the same cable. Specifically, thisAnnex specifies extensions to upstream bandwidth and maximum bit loading to support upstream data rates greater than
2 Mbit/s. This annex also defines those parameters of this ADSL system that have been left undefined in the main bodyof this Recommendation. An ADSL system implementing Annex I-EU shall support Annex I. It is recommended that an
ADSL system implementing Annex I also implements Annex C.
I.2

Definitions

Bitmap-FC
Bitmap-FR
Bitmap-NC
Bitmap-NR
Dual Bitmap
FEXT Bitmap
FEXTC duration
FEXTC symbol
FEXTR duration
FEXTR symbol
Hyperframe
NEXTC duration
NEXTC symbol
NEXTR duration
NEXTR symbol
NSCds

NSCus
NSWF
Subframe
TTR
TTRC
TTRR
UI

ATU-R transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-R
ATU-R transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-R
The Dual Bitmap method has dual bit rates under the FEXT and NEXT noise from TCM-ISDN
Similar to the Dual Bitmap method however transmission only occurs during FEXT noise fromTCM-ISDN
TCM-ISDN FEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN FEXTTCM-ISDN FEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN FEXT
5 Superframes structure which synchronized TTR
TCM-ISDN NEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN NEXT
TCM-ISDN NEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN NEXT
The highest subcarrier index that can be used for downstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCds = 256 for a downstream
channel using the frequency band up to 1.104MHz; NSCds = 512 for a downstream channel
using the frequency band up to 2.208MHz.
The highest subcarrier index that can be used for upstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCus = 64 for an upstream
channel using the frequency band up to 276 kHz.
Sliding Window frame counter10 consecutive DMT symbols (except for sync symbols) according to TTR timing
TCM-ISDN Timing Reference
Timing reference used in ATU-C
Timing reference used in ATU-R
Unit Interval

I.3

Reference Models

I.3.1

ATU-C transmitter reference model (replaces figures in 5.1)

See Figure I.1 and Figure I.2.

- 334 -

"Bits""Bits" &"Gains"
2*NSCds-1

AS0
AS1
AS2
AS3
LS0
LS1
LS2
NTR

crcf
Mux/
Sync
Control

crci

scram
&
FEC

Rate
converter

scram
&
FEC

Interleaver

Toneordering

Rate
converter

Constellation
encoderandgainscaling

2*NSCds-2
480
IDFT

OutputParallel/
SerialBuffer

1
n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameZi
C
i=1 to NSCds-1
Constellation
Encoder Input
Data FrameB
FEC Output
Data Frame

U-C

T1532760-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure I.1/G.992.1 – ATU-C transmitter reference model for STM transport
Annex I-EU does not currently support STM transport. It only supports ATM transport.

"Bits""Bits" &"Gains"
2*NSCds-1

AS0
ATM0

Cell TC
crcf

AS1
ATM1

Cell TC

NTR

Mux/
Sync
Control
crci

scram
&
FEC

scram
&
FEC

Rate
converterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

2*NSCds-2
480
IDFT
1

OutputParallel/
SerialBuffer

n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to NSCds-1
Constellation
Encoder Input
Data Frame

U-C

T1532770-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure I.2/G.992.1 – ATU-C transmitter reference model for ATM transport- 335 -

I.3.2

ATU-R transmitter reference model (replaces figures in 5.2)

See Figure I.3 and Figure I.4.

"Bits""Bits" &"Gains"LS02*NSCus-1
crcf

LS0
LS1

Mux/
Sync
ControlLS2

crci

scrambler&
FEC

scrambler
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

2*NSCus-2
59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR

B
FEC Output
Data Frame

Zi
i=1 to NSCus-1
C
Constellation
Encoder Input
Data Frame

U-R

T1532780-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (1.104 MHz).

Figure I.3/G.992.1 – ATU-R transmitter reference model for STM transport
Annex I-EU does not currently support STM transport. It only supports ATM transport.

- 336 -

"Bits"

2*NSCus-1

LS0
Cell TC

ATM0

LS1Cell TC

ATM1"Bits" &"Gains"

crcf
Mux/
Sync
Control
crci

scrambler&
FEC

scrambler&
FEC

2*NSCus-2

RateconverterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data FrameTTRR

B
FEC Output
Data FrameZi
C
i=1 to NSCus-1
Constellation
Encoder Input
Data Frame

U-R

T1532790-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (1.104 MHz).

Figure I.4/G.992.1 – ATU-R transmitter reference model for ATM transport
I.3.3
I.3.3.1

ATU-C/R transmitter timing model (replacement for 5.3)
TCM-ISDN crosstalk timing model (new)Figure I.5 shows the timing chart of the crosstalk from TCM-ISDN.

- 337 -TTR
377 UI
receive ISDN

transmit ISDNCO

0 ≤ propagation delay ≤ 16 UI
RT

6-7.5 UI

377 UI

receive ISDN

transmit ISDN

FEXTR

NEXTR

SC
TTRC

ATU-C TX

Frame Frame0 ≤ propagation delay ≤ 18.5 UI

Received
TTRC

SR

TTRR
NEXTC
ATU-R TXFEXTC

Frame Frame
T1532800-99

1 UI = 3.125 µs
FEXTR and NEXTR are estimated by ATU-CFEXTC and NEXTC are estimated by ATU-R

TTR

TCM-ISDN timing reference

TTRC

Timing reference used in ATU-C

Received TTR C Received TTRC at ATU-R
TTRRTiming reference used in ATU-R

SC

55 × 0.9058 µs: Offset from TTR to TTRC

SR

–42 × 0.9058 µs: Offset from received TTRC to TTRR

Figure I.5/G.992.1 – Timing chart of the TCM-ISDN crosstalk

The data stream of TCM-ISDN is transmitted in TTR period. CO transmits the stream in the first half of the TTR period
and RT transmits in the second half of the TTR period. ATU-C receives NEXT noise from the ISDN in the first half of
the TTR period and FEXT noise from the ISDN in the second half of the TCM-ISDN period. On the other hand,
ATU-R receives FEXT noise from the ISDN in the first half of the TTR period and NEXT noise from the ISDN in thesecond half of the TTR period.
As defined in I.7.6.2 and I.7.8.3, the ATU-C shall estimate the FEXTR and NEXTR duration at ATU-R, and the
ATU-R shall estimate FEXTC and NEXTC duration at ATU-C taking propagation delay on the subscribe line into
consideration.
The ATU-C shall transmit any symbols by synchronizing with the TTRC. The ATU-R shall transmit any symbols
synchronizing with the TTRR generated from received TTRC.

- 338 -

I.3.3.2

Sliding window (new)Figure I.6 shows the timing chart of the transmission for the Annex I-EU downstream at ATU-C.
Hyperframe = 345 symbols

TTRC
Crosstalk
period

FEXTR

FEXTR

FEXTR

FEXTR
NEXTR

NEXTR

ATU-C
T Frame
SWB
T1532810-99

FEXTR symbol
NEXTR symbol

Sliding Window

Figure I.6/G.992.1 – Sliding window for downstream symbols

The Sliding Window defines the transmission symbols under the crosstalk noise environment synchronized to theperiod of TTR. The FEXTC/R symbol represents the symbol completely inside the FEXTC/R duration. The NEXTC/R
symbol represents any symbol containing the NEXTC/R duration. Thus, there are more NEXTC/R symbols than
FEXTC/R symbols.
The ATU-C decides which transmission symbol is FEXTR or NEXTR symbol according to the sliding window andtransmits it with the corresponding bit table. Similarly, the ATU-R decides the transmission symbol is a FEXTC or
NEXTC and transmits it with the corresponding bit table. Although the phase of the sliding window is asynchronouswith TTRC/R, the pattern is fixed to the 345 frames of the hyperframe.
I.3.3.3

ATU-C Symbol Synchronization to TTR (new)345 symbols are 34 cycles with cyclic prefix of TTRC (or 32 cycles of TTRC without cyclic prefix). This implies a PLL
lock at the ATU-R.
I.3.3.4

Dual Bitmap switching (new)The ATU-C transmits FEXTR symbols using Bitmap-FR (in FEXTR duration), and transmits NEXTR symbols using
Bitmap-NR (in NEXTR duration) according to the result of initialization. The ATU-R transmits FEXTC symbols using
Bitmap-FC (in FEXTC duration), and transmits NEXTC symbols using Bitmap-NC (in NEXTC duration) in the samemanner.
The ATU-C shall have the capability to disable Bitmap-NC and Bitmap-NR (see I.4.5 and I.5.3).
I.3.3.5

Loop timing at ATU-R (new)The phase relation between received symbol and transmitted symbol of ATU-R at the reference point U-R shall meetthe phase tolerances as shown in Figure I.7.

- 339 -

(point U-R)
ATU-R receive
DMT symbol

ATU-R transmit
DMT symbol
T1532820-99±4.5 µs + SR

Figure I.7/G.992.1 – Loop timing for ATU-R

I.4

ATU-C functional characteristics (pertains to clause 7)

I.4.1

STM transmission protocols specific functionality (pertains to 7.1)

I.4.1.1

ATU-C input and output V interface for STM transport (replaces figure in 7.1.1)

See Figure I.8.

AS0 (n0 × 32 kbit/s)
AS1 (n1 × 32 kbit/s)
AS2 (n2 × 32 kbit/s)
AS3 (n3 × 32 kbit/s)
Digital
Network

twisted pair

LS0 ("C"; 16 or m0 × 32 kbit/s)

ATU-C

LS1 (m1 × 32 kbit/s)
LS2 (m2 × 32 kbit/s)
NTR
TTR
Operations, maintenance and control

T1532830-99

V-C
NOTE 1 – Optional bearer channels (both duplex and simplex) and features are shown with dotted lines.
NOTE 2 – TTR may be generated in the ATU-C without being provided from the V-C reference point.

Figure I.8/G.992.1 – ATU-C functional interfaces for STM transport at the V-C reference point- 340 -

I.4.1.2

Payload transfer delay (supplements 7.1.4)

Since Annex I-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.1.4.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
I.4.2
I.4.2.1

ATM transmission protocols specific functionalities (pertains to 7.2)
ATU-C Input and Output V interface for ATM transport (replaces figure in 7.2.1)

See Figure I.9.

ATM layer

ATM0
Tx_ATM0P
O
RT0

Tx_Cell_Handshake0
Rx_ATM0
Rx_Cell_Handshake0

ATM1
P
O
R
T
1

Twisted pair

Tx_ATM1
ATU-C
Tx_Cell_Handshake1
Rx_ATM1
Rx_Cell_Handshake1
NTR

and interface to
Digital network

TTR
Operations, administration,
maintenance and control
V-C

T1532840-99

NOTE – TTR can be generated in the ATU-C without being provided from the V-C reference point.

Figure I.9/G.992.1 – ATU-C functional interfaces to the ATM layer at the V-C reference point

I.4.2.2

Payload transfer delay (supplements 7.2.2)

Since Annex I-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.2.2.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
I.4.3
I.4.3.1

Framing (pertains to 7.4)
Superframe structure (supplements 7.4.1.1)

Since the rate converter reorders the user data and overhead bit-level data to create hyperframes, the input data frames
to the constellation encoder are different than those defined in 7.4.1.1.

- 341 -

I.4.3.2

Hyperframe structure (replaces 7.4.1.3)

Annex I-EU uses the hyperframe structure shown in Figure I.10. Figure I.10 shows the phase relationship between the
TTRC and the hyperframe at the point U-C. Each hyperframe is composed of 5 superframes, which are numbered from0 to 4. In order to indicate the boundary of the hyperframe, the inverse synch symbol is used for the 4th superframe(SPF#3), which is generated from a tone-by-tone 180-degree phase reversal of the synchronization symbol (see I.4.7.1)
except for the pilot tone.
The bit-level data stream from the rate-converter is extracted according to the size of Bitmap-FR and Bitmap-NR using
the Sliding Window (see I.3.3.2).
In order to make the bit rate to be a multiple of 32 kbit/s, the dummy bits are inserted at the end of hyperframe by therate converter (see I.4.4.2). The hyperframe is composed of 345 DMT symbols, numbered from 0 to 344. Each symbol
is assigned as FEXTR or NEXTR symbol in a FEXTR or NEXTR duration (see I.2), and the following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-C transmitter (see Figure I.11).
For Ndmt = 0, 1, ..., 344

S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > a + b) }elsethen FEXTR symbol
then NEXTR symbol

where a = 1243, b = 1461
Thus, 128 DMT symbols are allocated in the FEXTR duration, and 217 DMT symbols are allocated in the NEXTR
duration. The symbols are composed of:
FEXTR symbol:
Number of symbol using Bitmap-FR
Number of synch symbol
Number of inverse synch symbol
NEXTR symbol:

= 126
=1
=1

Number of symbol using Bitmap-NR= 214

Number of synch symbol=3

During FEXT Bitmap mode, the ATU-C shall transmit only the pilot tone in NEXTR symbols.

- 342 -

5 Superframe (= 340 frames)(point B)
1 Superframe = 68 frames (17 ms)

1 frame = 250 µs
Rate-Converter(point U-C, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#27

TC#33

TTR
ATU-R
Crosstalk

NEXT

FEXT

FEXT

Hyperframe = 345 symbols (85 ms)
SPF#1

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol F F F F N N N N N N F F

SSliding window

SPF#2
S

S

SPF#3
N F I

Inverse synch symbol

S

NEXTR Synch symbol

F

Symbol using Bitmap-FR (FEXTR duration bitmap)

N

Symbol using Bitmap-NR (NEXTR duration bitmap)

S

FEXTR Synch symbol

Figure I.10/G.992.1 – Hyperframe structure for downstream- 343 -SPF#4
F F

FEXTR duration

1 symbol = 246 µs
I

NEXT

N
T1532850-99

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

0
10
20
30

1

2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
21
22
23
24
25
26
27
28
29
40
31
32
33
34
35
36
37
38
39
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
SS
61
62
63
64
65
66
67
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100 101
101 102
103
104
105
106
107
108
109
110 111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
SS
132
133
134
135
136
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162 163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181 182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
SS
203
204
205
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233 234
235
236
237
238
239
240
241
242 243
253
244
245
246
247
248
249
250
251
252
263
254
255
256
257
258
259
260
260
262
264
265
266
267
268
269
270
271
272
273
274
276
277
278
279
280
281
282
283
ISS
284
285
286
287
288
289
290
291
292
293
295
296
297
298
299
300
301
302
303
294
304 305
306
307
308
309
310
311
312
313 314
315
316
317
318
319
320
321
322
323
324
334
325
326
327
328
329
330
331
332
333
SS
335
336
337
338
339
340
341
342
343
ISS

Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol
NEXTR data symbol

SS

NEXTR synch symbol
T1535330-00

Figure I.11/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Downstream

I.4.3.3

Subframe Structure (replaces 7.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table I.1. The 34 subframes forma hyperframe.

- 344 -

Table I.1/G.992.1 – Subframe (downstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

I.4.3.4

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Inverse Synch Symbol#344 is Synch Symbol

Reduced overhead framing with merged fast and sync bytes (modifies 7.4.3.2)

In S=1/2n framing mode (see §I.4.9), there are n Sync bytes per symbol time. The contents of the Sync bytes is thesame as in regular framing except that it repeats at n times the rate causing the superframe to be 68/n symbols in length.
The contents of the sync bytes are shown in Table 7-6/G.992.1. In S=1/2n framing mode, “Frame Number” in column 1
in Table 7-6/G.992.1 is replaced by “Sync Byte Index Number”.
As a result of the increase in superframe rate, the superframe contents is carried more frequently. For the case when
N=2, the EOC and AOC bandwidth doubles, thereby transferring actual messages at twice the rate. The CRC byte iscarried twice as frequently and therefore the maximum error rate rises from just over 58 per second to 117 per second.
Where the duration of an error condition is measured, this needs to be taken into consideration. The indicator bits arealso sent twice as often, which needs to be taken into consideration for statistics collection.
I.4.4

Dual Bitmapping and Rate Conversion (replaces 7.15)

The functions of the rate converter (see I.4.4.2), tone ordering (see I.4.6), constellation encoding, and gain scaling shalluse one of two bitmaps stored in the ATU. This method is called the dual bitmap.

- 345 -

I.4.4.1

Dual Bitmap (new)The Dual Bitmap method has individual bit rates under the FEXT and NEXT noise, and this needs an additional bit andgain table, {bi, gi}, and ordered bit table, b'i, for the tone ordering. The dual bitmaps are switched synchronized withthe sliding window pattern of NEXT/FEXT symbols. The number of bits and the relative gains to be used for every tone
are calculated in the bit loading algorithm during the initialization sequence, and transmitted in R-B&G.
I.4.4.2

Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FR, Bitmap-NR and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amount of fast and interleaved data in Bitmap-FR and Bitmap-NR shall be calculated with thefollowing formulae and illustrated in Figure I.12:
If tRf ≤ nRmax:n Rf = t Rf
nRi = nR − nRf
f Rf = t Rf
f Ri = f R − f Rf
If tRf > nRmax:

nRf = nR max

nRi = 0⎧⎡ t Rf × 10 − nRf × 6 ⎤⎪ f Rf 4 = ⎢
⎥
4
⎪
⎢
⎥
f Rf = ⎨⎡ t Rf ×10 − nRf × 7 ⎤⎪⎥⎪ f Rf 3 = ⎢3⎢⎥⎩⎧⎪ f Ri 4 = f R = f Rf 4
f Ri = ⎨⎪⎩ f Ri3 = f R − f Rf 3
Where:
tRf
tRi
fRf and nRf
fRf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FR and Bitmap-NR, respectively.
is the number of fast bits in Bitmap-FR if the subframe (see I.4.3.3) contains 3 Bitmap-FR except forsynch symbols.
fRf4
is the number of fast bits in Bitmap-FR if the subframe contains 4 Bitmap-FR except for synch
symbols.
fRi and nRi
are the numbers of interleaved bits in Bitmap-FR and Bitmap-NR, respectively.
nR
is the number of total bits in Bitmap-NR, which is specified in the B&G tables.
During FEXT Bitmap mode, nRf and nRi are zero.
To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tRf ≤ nRmax:- 346 -

dummy Rf = 0

dummy Ri = ( f Ri × 126 + nRi × 214) − t Ri × 340

If tRf > nRmax:()
dummy Rf 3 = ( f Rf × 3 + nRf × 7 ) − t Rf × 10

dummy Rf 4 = f Rf × 4 + nRf × 6 − t Rf ×10

dummy Ri = ( f Ri 4 × 96 + f Ri3 × 30 ) − t Ri × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FR constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:

dummy SRf = f Rf 3 − f Rf 4
The receiver shall determine Bitmap-FR and Bitmap-NR so that dummyRi is less than 126, dummyRf4 is less than 4 anddummyRf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.

- 347 -

#335#336#337#338#339#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25 #26 #27 #28 #29

tRi

Interleaved DatatRj

Fast Data

NOTE – Bit Ordering:
The earlier bit is located at the bottom
each symbol in this figure.
Rate Converter

Order

When tRf ≤ nRmax

fRi =fR – fRf

fR#4 #5 #6 #7 #8 #9

dummyRi#21 #22 #23#10 #11 #12 #13#0 #1 #2 #3#14 #15 #16 #17 #18 #19 #20#343#339#340#341#342#24 #25 #26 #27 #28 #29

nRinnRf=tRf R

fRf – tRf
FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe

When tRf > nRmax#0 #1 #2 #3#21 #22 #23#10 #11 #12 #13

dummyRi

fRi3

fRi4
dummyRf4

fR#335#336#337#338

dummyRf4

dummyRf3

dummy Rf4

fRf3
fRf4

#4 #5 #6 #7 #8 #9#14#15 #16 #17#18 #19 #20#26 #27 #28 #29#339#340#341#342#343

nRf = n
FEXTNEXT
Symbols Symbols
Subframe

FEXT
Symbols

NEXT
Symbols

Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe
T1532860-99

Figure I.12/G.992.1 – Bit distribution for Rate Converter under Dual latency and Dual Bitmap mode

I.4.5

FEXT Bitmapping (replaces 7.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (I.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures I.10 and I.16).
The Dual versus FEXT bitmapping mode is selected during G.994.1 using bit "DBM" (see 10.2 and 10.3).
I.4.6

Tone Ordering (replacement for 7.7)

A DMT time-domain signal has a high peak-to-average ratio (its amplitude distribution is almost Gaussian), and large
values may be clipped by the digital-to-analogue converter. The error signal caused by clipping can be considered as anadditive negative impulse for the time sample that was clipped. The clipping error power is almost equally distributed
across all tones in the symbol in which clipping occurs. Clipping is therefore most likely to cause errors on those tones- 348 -

that, in anticipation of a higher received SNR, have been assigned the largest number of bits (and therefore have thedensest constellations). These occasional errors can be reliably corrected by the FEC coding if the tones with the largest
number of bits have been assigned to the interleave buffer.
The numbers of bits and the relative gains in two bitmaps to be used for every tone are calculated in ATU-R receiver,and sent back to ATU-C according to a defined protocol (see 10.9.14). The pairs of numbers are typically stored, in
ascending order of frequency or tone numbers i, in bit and gain tables for Bitmap-FR and Bitmap-NR.
For Bitmap-FR, the "tone-ordered" encoding shall first assign fRf bits from the rate converter (see I.4.4.2) to the tones
with the smallest number of bits assigned to them, and the remaining fRi bits to the remaining tones. For Bitmap-NR, it
shall first assign nRf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nRi bits to the remaining tones.
All tones shall be encoded with the number of bits assigned to them; one tone in each bitmap may therefore have a
mixture of bits from the fast and interleaved buffers.
The ordered bit tables b'iF and b'iN shall be based on the original bit tables biF and biN as follows:
For k = 0 to Ndownmax {From the bit table, find the set of all i with the number of bits per tone bi = k
Assign bi to the ordered bit allocation table in ascending order of i}
Two ordered bit tables for Bitmap-FR and Bitmap-NR shall be prepared. A complementary de-ordering procedure
should be performed in ATU-R receiver. It is not necessary, however, to send the results of the ordering process to thereceiver because the bit tables FR and NR were originally generated in ATU-R, and therefore those tables have all theinformation necessary to perform the de-ordering.
I.4.7
I.4.7.1

Modulation (pertains to 7.11)
Inverse Synchronization Symbol (replaces 7.11.4)

Except for the pilot tone, Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phasereversal of Synchronization symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
I.4.7.2

Data subcarriers (modifies 7.11.1.1)

The channel analysis signal defined in 10.6.6 allows for a maximum of NSCds-1 carriers (at frequencies n∆f , n = 1 to
NSCds-1) to be used.
I.4.7.3

Nyquist frequency (modifies 7.11.1.3)

The carrier at the Nyquist frequency (#NSCds) shall not be used for user data and shall be real valued; other possible
uses are for further study.
I.4.7.4

Modulation by the inverse discrete Fourier transform (replaces 7.11.2)

The modulating transform defines the relationship between the 2*NSCds real values xn and the Zi:

xn =2* NSC −1⎛ jπni ⎞∑ exp⎜⎝ NSC ⎟⎠Zi =0i

for n = 0 to 2 * NSC − 1(7-21)The value of NSCds shall be 512 for this Annex.
The constellation encoder and gain scaling generate only NSCds-1 complex values of Zi. In order to generate realvalues of xn, the input values (NSCds-1 complex values plus zero at DC and one real value for Nyquist if used) shall beaugmented so that the vector Z has Hermitian symmetry. That is,- 349 -

Zi = conj (Z'2*NSCds-i)
I.4.7.5

for i = NSCds+1 to 2*NSCds-1(7-22)

Synchronization symbol (modifies 7.11.3)

The synchronization symbol permits recovery of the frame boundary after micro-interruptions that might otherwise
force retraining.
The data symbol rate, fsymb = 4 kHz, the carrier separation, ∆f = 4.3125 kHz, and the IDFT size, N = 2*NSCds, aresuch that a cyclic prefix of 15.625%*NSCds samples could be used. That is, when NSCds = 256, there are 40 samples
in the cyclic prefix.
(512 + 40) × 4.0 = 512 × 4.3125 = 2208

(7-23)

The cyclic prefix shall, however, be shortened to 12.5%*NSCds samples, and a synchronization symbol (with anominal length of NSCds*2.125 samples) is inserted after every 68 data symbols. That is,(2 + 0.125)*NSCds × 69 = (2 + 0.15625)*NSCds × 68(7-24)
The data pattern used in the synchronization symbol shall be the pseudo-random sequence PRD, (dn, for n = 1 to
2*NSCds) defined by:
dn = 1for n = 1 to 9
(7-25)
dn = dn-4 ⊕ dn-9

for n =10 to 2*NSCds(7-26)

The first pair of bits (d1 and d2) shall be used for the DC and Nyquist subcarriers (the power assigned to them is zero,so the bits are effectively ignored); the first and second bits of subsequent pairs are then used to define the Xi and Yi for
i = 1 to NSCds-1 as shown in Table 7-13.
The period of the PRD is only 511 bits, so dn+511 is equal to dn. The d1-d9 shall be re-initialized for eachsynchronization symbol, so each symbol uses the same data.
The two bits that modulate the pilot carrier, shall be overwritten by {0,0}: generating the {+,+} constellation.
The minimum set of subcarriers to be used is the set used for data transmission (i.e. those for which bi > 0); subcarriers

for which bi = 0 may be used at a reduced PSD as defined in transmit PSD paragraphs of Annexes A, B and C. The data
modulated onto each subcarrier shall be as defined above; it shall not depend on which subcarriers are used.
I.4.7.6

Cyclic prefix (replaces 7.12)

The last 12.5%*NSCds samples of the output of the IDFT (xn for n = 2*NSCds-0.125*NSCds to 2*NSCds-1) shall be
prepended to the block of 2*NSCds samples and read out to the digital-to-analogue converter (DAC) in sequence. For
example, when NSCds=256, the subscripts, n, of the DAC samples in sequence are 480 ... 511, 0 ... 511.
The cyclic prefix shall be used for all symbols beginning with the C-RATES1 segment of the initialization sequence, as
defined in 10.6.2.
I.4.8

ATU-C Downstream transmit spectral masks (replaces 7.14)

The downstream spectral masks of Annex I-EU are as specified in this section. When C-MSG1 bit 16 is 0, the PSD
mask as specified in § I.4.8.1 shall be used. When C-MSG1 bit 16 is 1, the PSD mask as specified in § I.4.8.2 shall be
used.
I.4.8.1

Downstream non-overlapped PSD mask definition

The non-overlapped PSD masks are defined with absolute peak values in Figure I.13. The low frequency stop band isdefined for frequencies below f1 kHz (tone n1); the high frequency stop band is defined at frequencies greater than
2208 kHz (tone 512). The in-band region of these PSD masks is the frequency band from f1 kHz to 2208 kHz.

- 350 -

–18 dB/octave

PSD indBm/Hz–36.5 dBm/Hz peak PSD–3 dB/octave–65 dB/octave

36 dB/octave–78 dB/octave–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHz–47.8 dBm/Hz–100 dBm/Hz peak PSD
in 10 kHz window
peak PSD
in 1 MHz window
above 3750 kHz–247 dB/octave–44.2 dBm/Hz–59.4 dBm/Hz–92.5 dBm/Hz–80 dBm/Hz–100 dBm/Hz

0

4

f3

f1

1104

1622

Frequency band f (kHz)0<f<4
4 < f < f3
f3 < f < f1
f1 < f < 1104
1104 < f < 1622
1622 < f < 2208
2208 < f < 2500
2500 < f < 3001.5
3001.5 < f < 3175
3925 < f < 12000

2208–110 dBm/Hz

3001.53750 4545
2500
3175

Equation for line (dBm/Hz)
-97.5
-92.5
-92.5 + 36*log2(f/f3)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 3.0*log2(f/1622)-47.8 – 65*log2(f/2208)-59.4 - 78*log2(f/2500)-80 – 247*log2(f/3001.5)-100

Frequency (kHz)04
4

PSD level (dBm/Hz)
-97.5
-97.5
-92.5

Measurement BW
100 Hz100 Hz100 Hz

f3
f1
f1
1104
1622
2208
2500
3001.5
3175
12000

-92.5
-44.2
-36.5
-36.5
-46.5
-47.8
-59.4
-80
-100
-100

10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz

Additionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
3750
4545
7225
12000

PSD level (dBm/Hz)
-100
-110
-112
-112

- 351 -

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

–112 dBm/Hz

7225

12000

Frequency
in kHzThe corner frequencies f1 and f3 depend on the associated upstream PSD mask used, see §I.5.6) and are defined asfollows:
Mask designator(DS-mm)
DS-32
DS-36
DS-40
DS-44
DS-48
DS-52
DS-56
DS-60
DS-64
DS-68
DS-72
DS-76
DS-80
DS-84
DS-88
DS-92
DS-96
NOTE 1 –NOTE 2 –NOTE 3 –NOTE 4 –NOTE 5 –NOTE 6 –Associatedupstream mask
EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64
EU-S68
EU-S72EU-S76
EU-S80EU-S84
EU-S88
EU-S92EU-S96

f1 (kHz)f3 (kHz)138
155.25172.5
189.75207
224.25241.5
258.75276
293.25310.5
327.75345
362.25379.5
396.75
414

54.45
61.26
68.06
74.87
81.67
88.48
95.29
102.09108.9115.71122.51129.32
136.12142.93149.74156.54163.35All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint withfrequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued
the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that
this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.
Figure I.13: Non-overlapped Downstream Channel PSD Masks.

Spectral Shaping of the In-Band Region defined in I.4.8.3 and Transmit Signals with Limited Transmit Power definedin I.4.8.4 shall be applied.
I.4.8.2

Downstream Overlapped PSD mask definition

The overlapped PSD mask is defined with absolute peak values in Figure I.14. The low frequency stop band is definedfor frequencies below 25.875 kHz (tone 6); the high frequency stop band is defined at frequencies greater than
2208 kHz (tone 512). The in-band region of this PSD mask is the frequency band from 25.875 kHz to 2208 kHz.

- 352 -

–18 dB/octave

PSD indBm/Hz–36.5 dBm/Hz peak PSD–3 dB/octave–65 dB/octave

21 dB/octave–78 dB/octave–46.5 dBm/Hz–97.5 peak
+15 dBrn
0-4 kHz–47.8 dBm/Hz–100 dBm/Hz peak PSD
in 10 kHz window
peak PSD
in 1 MHz window
above 3750 kHz–247 dB/octave–59.4 dBm/Hz–92.5 dBm/Hz–80 dBm/Hz–100 dBm/Hz

0425.8751104

1622

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < 1104
1104 < f < 1622
1622 < f < 2208
2208 < f < 2500
2500 < f < 3001.5
3001.5 < f < 3175
3925 < f < 12000

2208–110 dBm/Hz

3001.53750 4545
2500
3175

–112 dBm/Hz

7225

12000

Frequency
in kHzEquation for line (dBm/Hz)-97.5-92.5 + 21*log2(f/4)-36.5-36.5 - 18.0*log2(f/1104)-46.5 - 3.0*log2(f/1622)-47.8 – 65*log2(f/2208)-59.4 - 78*log2(f/2500)-80 – 247*log2(f/3001.5)-100

Frequency (kHz)04
4

PSD level (dBm/Hz)
-97.5
-97.5
-92.5

Measurement Bandwidth
100 Hz100 Hz100 Hz25.875
1104
1622
2208
2500
3001.5
3175
12000

-36.5
-36.5
-46.5
-47.8
-59.4
-80
-100
-100

10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz

Additionally, the PSD mask shall be satisfying following requirements:
Frequency (kHz)
3750
4545
7225
12000
NOTE 1 –NOTE 2 –NOTE 3 –PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement Bandwidth
1 MHz
1 MHz
1 MHz
1 MHz

All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint with- 353 -

frequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at themeasurement frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at
frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask
continued the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It wasrecognized that this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.

NOTE 4 –NOTE 5 –NOTE 6 –Figure I.14: Non-overlapped Downstream Channel PSD Mask.

I.4.8.3

Spectral Shaping of In-Band Region of PSD Spectrum

In order to shape the ATU-C PSD, frequency dependent gains, called spectral shaping values (ssvi ), shall be applied oneach tones during initialisation and showtime. The ssvi values shall be represented with 1 bit before and 10 bits after thedecimal point.
Table I.2 defines the corner points for the nominal PSD shape of the inband region as gain in dB, i.e log_ssvi. Log_ssvi
on other tones shall be linearly interpolated between corner points on a logarithmic scale for the gain (dB) and a linear
scale for the frequency (Hz). Note that the corner points defined in Table I.2 are relative values. Table I.3 defines thesimilar corner points for the overlapped spectrum.
The spectral shaping values shall be converted from logarithmic scale (log_ssvi, dB values) to linear ssvi values
according to:log_ ssvi⎛⎞⎜
Round ⎜1024 × 10 20 ⎟⎟⎝⎠ssvi =
1024

These points are not passed at initialization for the nominal PSD shape but are provided here for reference. However,for additional spectral shaping (see I.4.8.5), parameters are passed during G.994.1.
The combined accuracy of the process of linear interpolation of the log_ssvi values and the process of conversion tolinear ssvi values shall be strictly less than one half lsb of the 10 bit after the decimal point format of the linear ssvi
values. No error shall be introduced when log_ssvi equals 0dB or is interpolated between log_ssvi values, which equal
0dB.
NOTE 1:NOTE 2:

The above definition ensures that the maximum deviation between ssvi values used by transmitter andreceiver is one lsb.
The above needs an accuracy that is strictly < 1/2 lsb. An accuracy of = 1/2 lsb, will lead to inaccurate
results.

Table I.2: Corner points for the non-overlapped nominal in-band PSD shape.
Tone Index
n1

Log_ssvi (dB)
0

256
376
511

0
–10
–11.3

Comments
f1 kHz defines the beginning of the inband region. No shaping is applied in the
low stop band.
1104 kHz
1622 kHz ( –10 = -50 - Nominal_PSD_lowband)
2208 kHz ( –11.3 = -51.3 - Nominal_PSD_lowband)- 354 -

Table I.3: Corner points for the overlapped nominal in-band PSD shape
Tone Index
6

Log_ssvi (dB)
0

256
376
511

0
–10
–11.3

Comments
25.875 kHz defines the beginning of the inband region. No shaping is appliedin the low stop band.
1104 kHz
1622 kHz (–10 = -50 - Nominal_PSD_lowband)
2208 kHz (–11.3 = -51.3 - Nominal_PSD_lowband)

The absolute values of the transmit PSD are obtained by scaling the relative shaping values with a
NOMINAL_PSD_lowband, defined for the lower in-band frequencies. Note that the nominal in-band transmit PSD isfrequency dependent. The NOMINAL_PSD_lowband is –40 dBm/Hz (below 1104 kHz) for both the overlapped andnon-overlapped spectra.
NOTE 3: In-band PSD spectral shaping is applied prior to the IFFT.
NOTE 4: The value of MAXNOMATPds may be limited by regional regulations.
I.4.8.4

Transmit Signals with Limited Transmit PowerFor cases where the transmit signal must be limited to a maximum aggregate transmit power (e.g. ATPdsmax = +20dBm), thenf)During initialization the PSD transmit level is specified as an offset from the nominal value, i.e.
(Nominal_PSD_lowband + ssvi – x – power cutback) dB, and all values of gi = 1 for the offset value x and power
cutback. The same value of offset x is used for both overlapped and non-overlapped cases. The value of x shall be
the greater of 0 dB and (21.3 – ATPdsmax) dB. For ATPdsmax = 20 dBm, the corresponding value of x shall be
1.3 dB.

b)

If bi>0, then valid range for gi is [-14.5 to +2.5+x] (dB) ;If bi>0, then gi shall be in the [gsync – 2.5 to gsync + 2.5] (dB) range;
If bi=0, then gi shall be equal to 0 (linear) or in the [-14.5 to gsync] (dB) range;
For G.992.1 annex I-EU, gsync <= x dB

The gi values shall be constrainted by following relation:
Constraint on gi values

511

2

2

i =6

I.4.8.5

511∑ ssvi ∗ gi ≤ ∑ ssvi

2

i =6

Additional inband spectral shaping

An ATU-R may request additional downstream inband spectral shaping by passing parameters to the ATU-C in a
G.994.1 MP, or MS message. The ATU-C may select additional downstream inband spectral shaping by passing
parameters to the ATU-R in a G.994.1 MS message. Within the framework of G.994.1, the ATU-C has the ability tomake the final decision on the downstream inband PSD shape to be used.
The additional inband spectral shaping parameters are listed in I.7.2.2 and defined in I.7.3. If the Additional inband
spectral shaping Spar(2) bit is set to ONE in Table I.7.4, its associated Npar(3) octets in Tables I.7.4.1 to I.7.4.1.5
define the inband spectral shape. If the additional inband spectral shaping Spar(2) bit is set to ZERO, its associatedNpar(3) octets are not transmitted and the nominal inband PSD shape defined in I.4.8.3 shall be used. These Npar(3)octets define the downstream PSD levels in the low band (between f1 and 1104 kHz), at 1622 kHz and at 2208 kHz.
The PSD levels between 1104 kHz and 1622 kHz, and between 1622 kHz and 2208 kHz are linearly interpolated in log
scale. The defined values are the PSD level in dB below the NOMINAL_PSD_lowband of –40dBm/Hz. For example, if
all three values are set to 20 dB, the result will be a flat PSD of –60dBm/Hz. If the three values are set to 2 dB, 12 dB
and 15.5 dB, the result is the PSD defined in I.4.8.1 reduced by 2dB. In order not to violate the PSD mask defined in
I.4.8.1, the second value shall be no less than 10 dB and the third value shall be no less than 11.3 dB.

- 355 -

I.4.8.6

Egress control

G.992.1 Annex I-EU equipment shall be able to reduce the PSD below –80 dBm/Hz for the Amateur radio band
between 1.81 MHz and 2.00 MHz. The ATU-C may apply additional spectral shaping as described in I.4.8.5 to help
achieve this requirement.
I.4.9

Support of higher downstream bit rates with S = 1/2n (replaces 7.6.4)

With a rate of 4000 data frames per second and a maximum of 255 bytes (maximum RS codeword size) per data frame,
the ADSL downstream line rate is limited to approximately 8 Mbit/s per latency path. The line rate limit can beincreased beyond this for the interleaved path by mapping 2n RS codewords into one FEC data frame (i.e. by using S =1/2n in the interleaved path). S = 1/2n shall be used in the downstream direction only over bearer channel AS0.
For a selected value of n ≥ 1, the KI data bytes per interleaved mux data frame shall be packed into 2n RS codewords,
split into n equal parts, each consisting of 2 consecutive RS codewords. This forces rate adaptation to occur in 32n
kbit/s increments. Each of the n parts of the data frame shall begin with a sync byte and shall obey the rules defined inTable I.4 for insertion of dummy bytes. The smallest value of n that can support the KI data bytes shall be used.
Support of S = 1/2 (i.e., n=1) and S = 1/4 (i.e., n=2) is mandatory.

The resulting data frame structure shall be as shown in Figure I.15.
N1
Sync
Byte

PayloadN2 = N 1 or N 1-1

R

PayloadR

N2n-1 = N1
Sync
Byte

PayloadN2n = N2

R

PayloadR

NI
Figure I.15 – Data frame for S = 1/2n mode
When KI is divisible by 2n, the 2n codewords have the same length N2i-1 = N2i = (KI/2n + RI) for i = 1 to n, otherwise
the odd numbered codewords are equal and are one byte longer than the even numbered codewords, i.e. N2i-1 =(KI + n)/2n + RI bytes, and N2i = (KI – n)/2n + RI bytes for i = 1 to n. For the FEC output data frame, NI =

∑ N,
n

i =1

i

with NI < 512n - 1 bytes.
The convolutional interleaver requires all codewords to have the same odd length. To achieve the odd codeword length,
insertion of dummy (not transmitted) bytes may be required. For S = 1/2n, the dummy byte addition to the odd
numbered and/or even numbered codewords at the input of the interleaver shall be as in Table I.4.

Table I.4/G.992.1 –Dummy byte insertion at interleaver input for S = 1/2n
N2i-1
Odd
Even
Odd
Even

I.5

N2i
Odd
Even
Even
Odd

Dummy Byte Insertion Action
No action
Add one dummy byte at the beginning of all codewords
Add one dummy byte at the beginning of each even numbered codeword
Add one dummy byte at the beginning of each odd numbered codeword and two dummy bytes
at the beginning of each even numbered codeword [the de-interleaver shall insert one dummy
byte into the de-interleaver matrix on the first byte and the (D + 1)th byte of the corresponding
codeword to make the addressing work properly]

ATU-R Functional Characteristics (pertains to clause 8)- 356 -

I.5.1
I.5.1.1

Framing (pertains to 8.4)
Superframe structure (replaces 8.4.1.1)

The superframe structure of ATU-R transmitter is identical to that of ATU-C transmitter, as specified in I.4.3.1.
I.5.1.2

Hyperframe structure (replaces 8.4.1.3)

The hyperframe structure of ATU-R transmitter is functionally similar to that of ATU-C transmitter, except that theinverse synch symbol is used in the 1st superframe (SPF#0) (see Figure I.16). The hyperframe is composed of 345
DMT symbols, numbered from 0 to 344. Each symbol is under FEXTC or NEXTC duration (see I.5.3), and thefollowing numerical formula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-R
transmitter (see Figure I.17).
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbol
then NEXTC symbol

128 DMT symbols are allocated in the FEXTC duration, and 217 DMT symbols are allocated in the NEXTC duration.
The symbols are composed of:
FEXTC symbol:
Number of symbol using Bitmap-FC
Number of synch symbol
Number of inverse synch symbol
NEXTC symbol:
Number of symbol using Bitmap-NC
Number of synch symbol

= 126
=1
=1
= 214
=3

During FEXT Bitmapping mode, the ATU-R shall not transmit any signal.

- 357 -

5 Superframe (= 340 frames)(point B)

1 Superframe = 68 frames (17 ms)

1 frame = 250 µs

Rate-Converter(point U-R, including synch symbol)
TC#6

TTR Clock(TC)#0 = 2.5 ms

TC#33

TTRR
ATU-R
Crosstalk

NEXT

NEXT

FEXT
Hyperframe = 345 symbols (85 ms)

FEXT

ATU-C transmit
DMT symbol N N N N N F F F F N N N

SPF#2

SPF#1

Superframe (SPF#0) = 69 symbols (17 ms)

N F F I F N

S

S

SPF#3

SPF#4
S

S
T1532870-99

Sliding window

FEXTC duration

1 symbol = 246 µs
I

Inverse synch symbol

S

NEXTC Synch symbol

F

Symbol using Bitmap-FC (FEXTC duration bitmap)

N

Symbol using Bitmap-NC (NEXTC duration bitmap)

S

FEXTC Synch symbol

Figure I.16/G.992.1 – Hyperframe structure for upstream- 358 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

ISS

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

101

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

SS

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

17

173

174

175

176

177

178

179

180

181

172
182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

SS

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

244

245

246

247

248

249

250

251

252

253

24

243

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

SS

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

SS

ISS Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol SS NEXTR synch symbol
NEXTR data symbol

T1535340-00

Figure I.17/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Upstream

I.5.1.3

Subframe structure (replaces 8.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table I.5. The 34 subframes forma hyperframe.

- 359 -

Table I.5/G.992.1 – Subframe (upstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

I.5.2

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Inverse Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Synch Symbol#344 is Synch Symbol

Dual Bitmapping and rate conversion (replaces 8.15)

The function of the rate converter (see I.5.2.2), tone ordering (see I.5.4), constellation encoding, and gain scaling shalluse one of two bitmaps stored in the ATU. This method is called the dual bitmap.
I.5.2.1

Dual Bitmap (new)The Dual Bitmap switching shall be the same as for the downstream data, specified in I.4.4.1. The number of bits andthe relative gains to be used for every tone are calculated in the bit loading algorithm during the initialization sequence,and transmitted in C-B&G.
I.5.2.2
Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FC, Bitmap-NC and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amounts of fast and interleaved data in Bitmap-FC and Bitmap-NC shall be calculated in thefollowing formulae:
If tCf ≤ nCmax:- 360 -

nCf = tCf
nCi = nC − nCf
f Cf = tCf
f Ci = f C − f Cf
If tCf > nCmax:

nCf = nC max

nCi = 0⎧⎡ tCf × 10 − nCf × 6 ⎤⎪ f Cf 4 = ⎢
⎥
4
⎪
⎢
⎥
f Cf = ⎨⎡ tCf ×10 − nCf × 7 ⎤⎪⎥⎪ f Cf 3 = ⎢3⎢⎥⎩⎧ f Ci 4 = f C − f C 4
f Ci = ⎨⎩ f Ci 3 = f C − f Cf 3
Where:
tCf
tCi
fCf and nCf
fCf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of fast bits in Bitmap-FC if the subframe (see I.5.1.3) contains 3 Bitmap-FC except
for synch symbols.
fCf4
is the number of fast bits in Bitmap-FC if the subframe contains 4 Bitmap-FC except for synch
symbols.
fCi and nCi
are the numbers of interleaved bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of total bits in Bitmap-NC, which is specified in the B&G tables.
nC
During FEXT Bitmap mode, nCf and nCi are zero.
To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tCf ≤ nCmax:

dummyCf = 0

dummyCi = ( f Ci × 126 + nCi × 214) − tCi × 340
If tCf > nCmax:()
dummyCf 3 = ( f Cf × 3 + nCf × 7 ) − tCf ×10

dummyCf 4 = f Cf × 4 + nCf × 6 − tCf ×10

dummyCi = ( f Ci 4 × 96 + f Ci 3 × 30) − tCi × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FC constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:
dummySCf = fCf3 – fCf4

- 361 -

The receiver shall determine Bitmap-FC and Bitmap-NC so that dummyCi is less than 126, dummyCf4 is less than 4 anddummyCf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.
I.5.3

FEXT Bitmapping (replaces 8.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (I.4.4) to transmit data only during FEXT. The
ATU-C shall transmit only the pilot tone during the NEXTR symbol. The ATU-R disables Bitmap-NC and shall nottransmit any signal during the NEXTC symbol (see Figures I.10 and I.16).
The Dual versus FEXT bitmapping mode is selected during G.994.1 using bit "DBM" (see 10.2 and 10.3).
I.5.4

Tone Ordering (pertains to 8.7)

The tone ordering algorithm shall be the same as for the downstream data, specified in I.4.4.
For Bitmap-FC, the "tone-ordered" encoding shall first assign fCf bits from the rate converter (see I.5.2.2) to the tones
with the smallest number of bits assigned to them, and the remaining fCi bits to the remaining tones. For Bitmap-NC, it
shall first assign nCf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nCi bits to the remaining tones. Two ordered bit tables for Bitmap-FC and Bitmap-NC shall be prepared.
I.5.5
I.5.5.1

Modulation (pertains to 8.11)
Inverse synchronization symbol (replaces 8.11.4)

Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phase reversal of Synchronization
symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
I.5.5.2

Gain scaling in synchronization symbol (new)At initialization time, the sync symbol reference transmit PSD level shall be set at the nominal PSD level+10log(gsync2) dBm/Hz, with gsync2 defined as the average gi2 value over the used (i.e. bi > 0) subcarriers in theNEXT or FEXT bitmap, whichever results in the highest average gain. The sync symbol reference transmit PSD shallnot be updated with used subcarrier gain changes during SHOWTIME.
I.5.5.3

Nyquist frequency (supplements 8.11.1.2)

The upstream Nyquist frequency for Annex I-EU shall be at subcarrier NSCus (f = 4.3125*NSCus kHz)..
I.5.5.4

Modulation by the inverse discrete Fourier transform (supplements 8.11.2)

For Annex I-EU, see A.2.1.
I.5.5.5

Synchronization symbol (supplements 8.11.3)

For Annex I-EU, see A.2.2.

I.5.6

ATU-R Upstream Transmit Spectral Mask (replaces 8.14)

The upstream PSD masks of Annex I-EU are defined with absolute peak values in Figure I.18. The low frequency stopband is defined for frequencies below 25.875 kHz; the high frequency stop band is defined at frequencies greater than
f1 kHz (tone n1). The in-band region of these PSD masks is the frequency band from 25.875 kHz to f1 kHz.
and the ATU-R may optionally support upstream masks EU-36 to EU-64. specified in Figure I.18
NOTE: The value of MAXNOMATPus may be limited by regional regulations.

- 362 -

PSD indBm/HzPEAKPSD(PEAKPSD+92.5)/2.69
dB/octave–72 dB/octave–100 dBm/Hz peak
–15 dB/octave–97.5
15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 1411 kHz–92.5 peak
PSD_int dBm/Hz–110 dBm/Hz–112 dBm/Hz

0425.875

f1

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < f1
f1< f < f_int
f_int < f < 686
f > 686
Frequency (kHz)04
425.875f1
f_int
686 – 12000

f_int

686

1411
1630 5275

Equation for line (dBm/Hz)-97.5-92.5+(PEAKPSD+92.5)* log2(f/4)/log2(25.875/4)
PEAKPSDPEAKPSD-72*log2(f/f1)
PSD_int-15*log2(f/f_int)-100
PSD level (dBm/Hz)
-97.5
-97.5
-92.5
PEAKPSDPEAKPSD
PSD_int-100

Measurement BW
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz

Additionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
1411
1630
5275
12000

Frequency
12000 in kHz

PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

NSCus is a function of the upstream mask parameters, which are defined as follows:- 363 -

Parameters in FEXT bitmap for mode 1, both bitmaps for mode 2 (see §I.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

32
64
64
64
64
64
64
64
64

Template
Nominal PSD
P0 (dBm/Hz)

-38.0
-38.5
-39.0
-39.4
-39.8
-40.1
-40.4
-40.7
-41.0

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.0
-35.5
-35.9
-36.3
-36.6
-36.9
-37.2
-37.5

138.00155.25172.50189.75207.00224.25241.50258.75276.00242.92274.03305.06336.33367.54399.07430.58462.04493.45

-93.2
-94.0
-94.7
-95.4
-95.9
-96.5
-97.0
-97.4
-97.9

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.2
-36.4
-37.2
-37.9
-38.3
-38.6
-38.8
-38.8

138.00155.25172.50189.75207.00224.25241.50258.75276.00242.92273.47302.26331.87361.55392.16423.12454.51486.91

-93.2
-94.0
-94.7
-95.3
-95.8
-96.4
-96.9
-97.3
-97.8

Parameters in NEXT bitmap for mode 1 (see §I.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

Template
NominalPSD P0(dBm/Hz)

32
64
64
64
64
64
64
64
64

-38.0
-38.7
-39.9
-40.7
-41.4
-41.8
-42.1
-42.3
-42.3

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

NOTE 1 – All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
NOTE 2 – The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The breakpoints
in the tables shall be connected by linear straight lines on a dB/log(f) plot.
NOTE 3 – MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint with frequency fi
is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next specified breakpoint.
NOTE 4 – The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
NOTE 5 – The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued the21.5 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that this might impact
V.90 performance, and so the floor was extended to 4 kHz.
NOTE 6 – All PSD and power measurements shall be made at the U-R interface (see Figures I.3 & I.4).
Figure I.18: Upstream Channel PSD Masks
When EU-S68 or beyond is used, only mode 2 shall be used. The PSD masks are defined in Figure I.x1 and Table I.x2.
The frequency band from 25.875 kHz to f_upper can be used.

- 364 -

Frequency band f (kHz)
Equation for line (dBm/Hz)
0<f<4
-97.5
4 < f < 25.875-92.5+(PEAKPSD+92.5)* log2(f/4)/log2(25.875/4)
25.875 < f < f1
PEAKPSDf1< f < f_upper
PEAKPSD-24*log2(f/f1)
f_upper < f < 686
PSD_upper-((PSD_upper+100)/log2(686/f_upper))*log2(f/f_upper)f > 686-100
Note: PSD_upper=PEAKPSD-24*log2(f_upper/f1)

Frequency (kHz)04
4
1025.875276
f_upper
686
5275
12000

PSD level (dBm/Hz)
-97.5
-97.5
-92.5
interpolated
-38.6
-38.6
PSD_upper
-100
-100
-100

Measurement BW
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHzFigure I.x1: Mask definition for EU-S68 to EU-S96

Designator
EU-S68
EU-S72EU-S76
EU-S80EU-S84
EU-S88
EU-S92EU-S96

Template
Maximum
Aggregate
Transmit Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

Upper
Frequency
f_upper(kHz)

PSD_upper:
PSD Level at
f_upper(dBm/Hz)293.25
310.50327.75345.00362.25379.50396.75414.00-40.70-42.68-44.55-46.33-48.02-49.63-51.17-52.64

Table I.x2: Parameters for EU-S68 to EU-S96- 365 -

I.5.7

Forward error correction (supplements 8.6)

The minimum FEC coding capabilities (Table 8-3) for an ATU-R shall include the following interleave depths for theinterleaved buffer:
D = 1, 2, 4, 8, and 16
I.5.8

Cyclic prefix (supplements 8.12)

For Annex I-EU, see A.2.3.

I.6

EOC Operation and Maintenance (pertains to clause 9)

I.6.1

ADSL line related primitives (supplements 9.3.1)

I.6.1.1

ADSL line related near-end defects (supplements 9.3.1.3)

Two near-end defects are further defined:••

I.6.1.2

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.
Severely errored frame (SEF): A SEF defect occurs when the content of two consecutively received ADSL
synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R, does notcorrelate with the expected content over a subset of the tones. An SEF defect terminates when the content of twoconsecutively received ADSL synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR
duration at ATU-R, correlate with the expected contents over the same subset. The correlation method, theselected subset of tones, and the threshold for declaring these defect conditions are implementation discretionary.
ADSL line related far-end defects (supplements 9.3.1.4)

Loss-of-signal is further defined:•

I.6.2
I.6.2.1

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.
Test Parameters (supplements 9.5)
Near-end test parameters (supplements 9.5.1)

The near-end primitives are further defined:••

I.6.2.2

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio (SNR) margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.
Far-end test parameters (supplements 9.5.2)

The far-end primitives are further defined:•

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.

- 366 -

•

I.6.3

Signal-to-Noise ratio SNR margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.
Data registers in the ATU-R (supplements 9.2.4)

For the S=1/2n framing mode (see §I.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).
I.7

Initialization (pertains to clause 10)

I.7.1

Initialization with Hyperframe (replaces 10.1.5)

The exchange of messages between ATU-C and ATU-R should be performed in FEXTC and FEXTR. The DMT
symbol has two symbol rates: one is 4.3125 kbaud for the symbol without a cyclic prefix, and the other is 4 x 69/68
kbaud for the symbol with a cyclic prefix. 32 times of the TTR has the same period as 345 times of the 4.3125 kbaud,
and 34 times of the TTR is the same as 345 times of 4 x 69/68 kHz.
During FEXT Bitmap mode, the ATU-R shall not transmit any signal during the NEXTC symbols duration and the
ATU-C shall transmit only the pilot tone as the NEXTR signal except:• C-PILOT1 (C-PILOT1A) which is accompanied by a signal to allow the ATU-C to indicate the phase of TTRC
to the ATU-R (see I.7.4.1);• C-QUIETn where no signal is transmitted.
The ATU-C begins transmitting C-PILOT1 at the beginning of the hyperframe without cyclic prefix. The ATU-C
informs the phase of the TTRC to ATU-R during C-PILOT1. The ATU-R begins transmitting R-REVERB1 at the
beginning of the hyperframe without cyclic prefix. The ATU-R performs the training of any receiver equalizer using
this phase information of the TTRR generated from received TTRC.
From C-PILOT1 to C-SEGUE1, the following numerical formula gives the information which duration Ndmt-th DMT
symbol belongs to at ATU-R (see Figure I.19).
For Ndmt = 0, 1, …344
S = 256 x Ndmt mod 2760
if { (S + 255 < a) or (S > a + b) }else
where a = 1243, b = 1461

then FEXTR symbols
then NEXTR symbols

In order to enter C-RATES1 at the beginning of the hyperframe with cyclic prefix, the number of symbols from
C-PILOT1 to C-SEGUE1 shall be a multiple of 345 DMT symbols.
From R-REVERB1 to R-SEGUE1, the following numerical formula gives the information which duration Ndmt-th
symbol belongs to at ATU-C (see Figure I.20).
For Ndmt = 0, 1, …, 344,
S = 256 x Ndmt mod 2760
if { (S > a) and (S + 255 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols

From C-RATES1 to C-SEGUE3, the number of symbols is a multiple of 345 DMT symbols. The following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-C transmits the message data in
FEXTR symbols (see Figure I.11).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760

- 367 -

if { (S + 271 ≥ a) and (S ≤ a + b) }else
where a = 1243, b = 1461

then NEXTR symbols
then FEXTR symbols

The ATU-R enters R-REVERB3 at the beginning of the hyperframe with cyclic prefix, which is extracted fromreceived signal. From R-REVERB3 to R-SEGUE5, the number of symbols is a multiple of 345 DMT symbols. The
following numerical formula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-R transmits
the message data in FEXTC symbols (see Figure I.17).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols- 368 -

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14

0

1

2

3

4

5

6

7

8

9

10

11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
107
97
98
99
100
101
102
103
104
105
106
108
109
110
111
112
113
114
115
116
117 118
119
120
121
122
123
124
125
126
127
128
129 130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
161
151
152
153
154
155
156
157
158
159
160

162
163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181
182
184
185
186
187
188
189
190
191
192
193
17 183
204
195
196
197
198
199
200
201
202
203
18 194
205
206
207
208
209
210
211
212
213
214 215
19
20
216
217
218
219
220
221
222
223
224
225
228
229
230
231
232
233
234
235
236
21 226 227
238
239
240
241
242
243
244
245
246
247
22 237
258
248
249
250
251
252
253
254
255
256
257
23
24
259
260
261
262
263
264
265
266
267
268 269
15
16

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311 312
313
314
315
316
317
318
319
320
321
322
29
323
324
325
326
327
328
329
330
331
332
333
30
335
336
337
338
339
340
341
342
343
344
31 334
25
26
27
28

280

FEXTR symbol

T1535350-00

NEXTR symbol

Figure I.19/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Downstream- 369 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

10

1

11

12

13

14

15

16

17

18

19

20

2

22

23

24

25

26

27

28

29

30

31

3 32
4 43
5

33

34

44

54

35

45

55

6

65

7 75
8 86

76

56

66

57

77
98

99

108

109

110

23
24

82

92

102

112

62

72

63

73

83

93

103

113

64

74

84

94

104

114

53

85

95

105

115

96
107

106

116

117

118

121

122

123

124

125

126

127

128

132

133

134

135

136

137

138

139

142

143

153

163

144

154

164

145

155

165

146

156

166

147

157

167

148

158

168

149

159

169

150
161

160

170

171

172

174

175

176

177

178

179

180

181

182

184

185

186

187

188

189

190

191

192

193
204

195

205

196

206

216

21 22622 239

81

91

101

111

61

71

42

52

173

17 18318 194
19
20

80

41

51

131
152

162

15
16

60

70

90

40

50

120

141

140
151

59

79
100

39

49

69

89

97

14

58

78

9

38

48

68

88

10

13

37

47

67

87

119
11
12 129 130

36

46

21

197

207

217

198

208

218

199

209

219

200

210

220

201

211

221

202

212

222

203

213

223

215

214

224

225

227

228

229

230

231

232

233

234

235

236

238

239

240

241

242

243

244

245

246

247
258

248

249

259

250

260

251

261

252

262

253

263

254

264

255

265

256

266

257

267

268

269

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
26 280
292
293
294
295
296
297
298
299
300
301
27 291
28
302
303
304
305
306
307
308
309
310
311
312
25

29
30 32331 334

313

314

324
335

315

325
336

316

326
337

317

327

318

328

338

339

319

329
340

320

330
341

321

331
342

322

332
343

333
344
T1535360-00

FEXTC symbol
NEXTC symbol

Figure I.20/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Upstream
I.7.2

Handshake – Non-standard information block (new)This section defines the format of the G.994.1 non-standard information block to support Annex I-EU, and tabulates theparameters used by Annex I-EU. The use of these parameters is described in §I.7.3 and §I.7.4.

I.7.2.1

Non-standard information block format (new)Figure I.21 defines the format of the non-standard information block.

- 370 -

8

7

6

5

4

3

2

1

Non-standard information length = M + 6(1 octet)
T.35 country code
(2 octets – see Note 1)
Provider code (vendor identification)(4 octets – see Note 2)
Vendor-specific information(M octets – Note 3)
NOTE 1 – The value of this field shall be B5 00, the country code for USA
NOTE 2 – The value of this field shall be 43 45 4E 54, ASCII “CENT” for Centillium
Communications
NOTE 3 – These octets are defined in §I.7.2.2. Formatting of these octets shall comply with theparsing rules defined in G.994.1 §9.2.1 to §9.2.3

Figure I.21 – Non-standard information block format

I.7.2.2

Non-standard information block parameters (new)The G.994.1 non-standard parameters for Annex I-EU are listed in Tables I.6 to I.7.4.2 below.
In order to minimize message length, the parameters for additional inband spectral shaping (Spar(2) octet and its related
Npar(3) octets) shall only be included in MP or MS messages, and shall not be included in CLR or CL messages. All
Annex I-EU modems shall support additional inband spectral shaping.
Note - This deviates from the rules specified in G.994.1 for standard information fields, where it isstated in §9.6:“Once a Transaction C (see 10.1) has been completed, any subsequent MS message
within the same G.994.1 session shall only contain those octets of the identification (I)and standard information (S) fields, and those blocks of non-standard information (NS)that were contained in both the CLR and CL messages of the previous Transaction C”.

Table I.6 – Non-standard information field – NPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Reserved for future use

x

x

x

x

x

x

1

x

Reserved for future use

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet- 371 -

NPar(1)sTable I.7 – Non-standard information field – SPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

G.992.1 Annex Q (and Annex Q-EU)

x

x

x

x

x

x

1

x

G.992.1 Annex I-EU

x

x

x

x

x

1

x

x

G.992.1 Annex C-EU

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet

SPar(1)sTable I.7.3 – Non-standard information field – G.992.1 Annex I-EU NPar(2) coding – Octet 1
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

nC-PILOT1 = 64

x

x

x

x

x

x

1

x

nC-PILOT1 = 128

x

x

x

x

x

1

x

x

nC-PILOT1 = 256

x

x

x

x

1

x

x

x

Amateur radio notch – 1.8 MHz band

x

x

x

1

x

x

x

x

Reserved for future use

G.992.1 Annex I-EU NPar(2)s

x

x

1

x

x

x

x

x

nC-PILOT1 = 96

x

x

0

0

0

0

0

0

No parameters in this octet

Since A48 is the only TTR indication signal specified for Annex I-EU, there is no need to include it in G.994.1.

Table I.7.3.1 – Non-standard information field – G.992.1 Annex I-EU NPar(2) coding – Octet
2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

R-ACK1

x

x

x

x

x

x

1

x

R-ACK2

G.992.1 Annex I-EU NPar(2)s – Octet 2

x

x

x

x

x

1

x

x

DBM

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

G.997.1 – Clear EOC OAM

x

x

0

0

0

0

0

0

No parameters in this octet

Since Annex I-EU only supports ATM transport, STM and ATM parameters are not specified.

- 372 -

Table I.7.4 – Non-standard information field – G.992.1 Annex I-EU SPar(2) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Additional inband spectral shaping

x

x

x

x

x

x

1

x

Extended upstream

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex I-EU SPar(2)s

Table I.7.4.1 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 1
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 1
NOMINAL_PSD_lowband (bits 8 & 7)
Reserved for future use

Table I.7.4.1.1 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 2
NOMINAL_PSD_lowband (bits 6 to 1)

Table I.7.4.1.2 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 3
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 3
PSD level at 1622 kHz (bits 8 & 7)
Reserved for future use- 373 -

Table I.7.4.1.3 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 4
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 4
PSD level at 1622 kHz (bits 6 to 1)

Table I.7.4.1.4 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 5
Bits
8

7

x

x

x

x

6
x

5
x

4
x

3

2

1

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 5
PSD level at 2208 kHz (bits 8 & 7)
Reserved for future use

Table I.7.4.1.5 – Non-standard information field – G.992.1 Annex I-EU Additional inband
spectral shaping Npar(3) coding
Octet 6
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

x

G.992.1 Annex I-EU Additional inband spectral
shaping Npar(3)s Octet 6
PSD level at 2208 kHz (bits 6 to 1)

Table I.7.4.2 – Non-standard information field – G.992.1 Annex I-EU Extended upstream
NPar(3) coding Octet 1
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Mode 1 upstream mask

x

x

x

x

x

x

1

x

Mode 2 upstream mask

x

x

x

x

x

1

x

x

Optional upstream masks for non-overlapped spectrum

x

x

x

x

1

x

x

x

EU-64

x

x

x

1

x

x

x

x

EU-32

x

x

1

x

x

x

x

x

EU-36

x

x

0

0

0

0

0

0

No parameters in this octet- 374 -

G.992.1 Annex I-EU Extended upstream NPar(3)sOctet 1

Table I.7.4.2.1 – Non-standard information field – G.992.1 Annex I-EU Extended upstream
NPar(3) coding Octet 2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

EU-40

x

x

x

x

x

x

1

x

EU-44

x

x

x

x

x

1

x

x

EU-48

x

x

x

x

1

x

x

x

EU-52

x

x

x

1

x

x

x

x

EU-56

x

x

1

x

x

x

x

x

EU-60

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex I-EU Extended upstream NPar(3)sOctet 2

Table I.7.4.2.2 – Non-standard information field – G.992.1 Annex I-EU Extended upstream
NPar(3) coding Octet 3
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

EU-S68

x

x

x

x

x

x

1

x

EU-S72

x

x

x

x

x

1

x

x

EU-S76

x

x

x

x

1

x

x

x

EU-S80

x

x

x

1

x

x

x

x

EU-S84

x

x

1

x

x

x

x

x

EU-S88

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex I-EU Extended upstream NPar(3)sOctet 3

Table I.7.4.2.3 – Non-standard information field – G.992.1 Annex I-EU Extended upstream
NPar(3) coding Octet 4
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

EU-S92

x

x

x

x

x

x

1

x

EU-S96

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex I-EU Extended upstream NPar(3)sOctet 4

I.7.3

Handshake – Parameter definitions (supplements 10.2)

I.7.3.1

Handshake – ATU-C (supplements 10.2)- 375 -

I.7.3.1.1

CL messages (supplements 10.2.1)

See Table I.8.

- 376 -

Table I.8/G.992.1 – ATU-C CL message NPar(2) bit definitions for Annex I-EU
NSF parameter
DBM

Definition
If set to ZERO, this bit shall indicate Bitmap-NR and Bitmap-NC are enabled (Dual Bitmapmode) and are used to transmit data. If set to ONE, this bit shall indicate Bitmap-NR andBitmap-NC are disabled (FEXT Bitmap mode), i.e. only Bitmap-FR and Bitmap-FC areused to transmit data by ATU-C and ATU-R respectively. This mode selection shall be only
performed by the ATU-C. If it is set to ONE in a CL message, it must be set to ONE in
subsequent MS messages from either the ATU-C or ATU-R.

G.992.1 Annex I-EU

If set to ONE, this Spar(1) bit indicates that the ATU-C is configured to support G.992.1
Annex I-EU.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission ofpilot tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission ofpilot tone on subcarrier 96.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission ofpilot tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission ofpilot tone on subcarrier 256.
If set to ONE, this Npar(2) bit indicates that the ATU-C is configured to reduce its transmit
power between 1.81 and 2.0 MHz to ≤ –80 dBm.
If set to ONE, this Spar(2) bit indicates that the ATU-C is configured to support extended
upstream.
If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-C supports. For non-overlapped spectrum, extended
upstream masks are associated with downstream masks according to Figure I.13. For
overlapped spectrum, any EU-xx may be used with the overlapped downstream spectrum
specified in §I.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support theoptional upstream masks when using non-overlapped spectrum downstream.

nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum

I.7.3.1.2

MS messages (supplements 10.2.2)

See Table I.9.

- 377 -

Table I.9/G.992.1 – ATU-C MS message NPar(2) bit definitions for Annex I-EU
NSF parameter
DBM

Definition
If set to ZERO, this bit shall indicate Bitmap-NR and Bitmap-NC are enabled (Dual
Bitmap mode) and are used to transmit data. If set to ONE, this bit shall indicate
Bitmap-NR and Bitmap-NC are disabled (FEXT Bitmap mode), i.e. only Bitmap-FR andBitmap-FC are used to transmit data by ATU-C and ATU-R respectively. This mode
selection shall be only performed by ATU-C. This bit shall be set to ONE if it was set to
ONE in a previous CL message.

G.992.1 Annex I-EU
nC-PILOT1=64

If set to ONE, this Spar(1) bit indicates that the ATU-C is selecting G.992.1 Annex I-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 96 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 256 (Note 1).
If set to ONE, this Npar(2) bit indicates that the ATU-C shall reduce its transmit power
between 1.81 and 2.0 MHz to ≤ –80 dBm.
If set to ONE, this Spar(2) bit indicates that the ATU-C shall apply additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD levelat 1622 kHz, and PSD level at 2208 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply in the passband below 1104 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-C
shall apply at 2208 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 2208 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-C is selecting extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-C is selecting upstream PSD mask
US-xx. For non-overlapped spectrum, extended upstream masks are associated withdownstream masks according to Figure I.13. For overlapped spectrum, any EU-xx may be
used with the overlapped downstream spectrum specified in §I.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 1(different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 2(same mask during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch –1.8 MHz band
Additional inband
spectral shaping
REDUCED_PSD_low
band
PSD level at 1622 kHz

PSD level at 2208 kHz

Extended upstream
EU-xx

Mode 1 upstream mask
Mode 2 upstream mask

Optional upstream
masks for nonoverlapped spectrum
Note 1: One and only one pilot tone bit shall be set in an MS message.
Note 2: One and only one upstream mask mode bit shall be set in an MS message.

I.7.3.2

Handshake – ATU-R (supplements 10.3)- 378 -

I.7.3.2.1

CLR messages (supplements 10.3.1)

See Table I.10.

- 379 -

Table I.10/G.992.1 – ATU-R CLR message NPar(2) bit definitions for Annex I-EU
NSF parameter
DBM

G.992.1 Annex I-EU
nC-PILOT1=64
nC-PILOT1=96
nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Extended upstream
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum

I.7.3.2.2

Definition
This bit shall be set to ONE.

If set to ONE, this Spar(1) bit indicates that the ATU-R is configured to support G.992.1
Annex I-EU.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 64.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 96.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot
tone on subcarrier 256.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports the 1.8 MHz
Amateur radio band notch.
If set to ONE, this Spar(2) bit indicates that the ATU-R is configured to support extended
upstream.
If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-R supports. For non-overlapped spectrum, extended upstream
masks are associated with downstream masks according to Figure I.13. For overlapped
spectrum, any EU-xx may be used with the overlapped downstream spectrum specified in§I.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support the optional
upstream masks when using non-overlapped spectrum downstream.

MS messages (supplements 10.3.2)

Table I.11.

Table I.11/G.992.1 – ATU-R MS message NPar(2) bit definitions for Annex I-EU
NSF parameter
DBM

Definition
If set to ZERO, this bit shall indicate Bitmap-NR and Bitmap-NC are enabled (Dual
Bitmap mode) and are used to transmit data. If set to ONE, this bit shall indicate
Bitmap-NR and Bitmap-NC are disabled (FEXT Bitmap mode), i.e. only Bitmap-FR andBitmap-FC are used to transmit data by ATU-C and ATU-R respectively. This mode
selection shall be only performed by ATU-C. This bit shall be set to ONE if it was set to
ONE in a previous CL message.

G.992.1 Annex I-EU
nC-PILOT1=64

If set to ONE, this Spar(1) bit indicates that the ATU-R is selecting G.992.1 Annex I-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 96 (Note 1).

nC-PILOT1=96- 380 -

nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Additional inband
spectral shaping
REDUCED_PSD_lo
wband
PSD level at 1622
kHz

PSD level at 2208
kHz

Extended upstream
EU-xx

If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shalleither be set to the same value as in a previous CL message or set to ONE.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting additional
downstream inband spectral shaping as defined by the values of
REDUCED_PSD_lowband, PSD level at 1622 kHz, and PSD level at 2208 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATUR wishes to have applied in the passband below 1104 kHz. It is coded in steps of
0.125dB relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000
means –40 dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATUR wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622
kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATUR wishes to have applied at 2208 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 2208 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-R is selecting upstream PSD mask
US-xx. For non-overlapped spectrum, extended upstream masks are associated used withdownstream masks according to Figure I.13. For overlapped spectrum, any EU-xx may
be used with the overlapped downstream spectrum specified in §I.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode
1 (different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode
2 (same mask during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum
Note 1: One and only one pilot tone bit shall be set in an MS message.
Note 2: One and only one upstream mask mode bit shall be set in an MS message.

I.7.3.2.3

MP messages (new)Table I.12.
Table I.12/G.992.1 – ATU-R MP message NPar(2) bit definitions for Annex I-EU
NSF parameter
R-ACK1
R-ACK2
G.992.1 Annex I-EU
nC-PILOT1=64
nC-PILOT1=96

Definition
Proposes that the ATU-C send C-PILOT1A, C-QUIET3A, C-PILOT2 and C-QUIET5 duringtransceiver training.
Proposes that the ATU-C send C-PILOT1, C-PILOT2 and C-PILOT3 during transceivertraining.
If set to ONE, this Spar(1) bit indicates that the ATU-R is proposing G.992.1 Annex I-EU.
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 64 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is proposing the pilot tone on
subcarrier 96 (Note 1).

- 381 -

nC-PILOT1=128
nC-PILOT1=256
Amateur radio notch– 1.8 MHz band
Additional inband
spectral shaping
REDUCED_PSD_lo
wband
PSD level at 1622
kHz

PSD level at 2208
kHz

Extended upstream
EU-xx

If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 128 (Note 1).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 256 (Note 1).
This selection shall only be performed by the ATU-C. Therefore, this Npar(2) bit shall either
be set to the same value as in a previous CL message or set to ONE.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing additional downstream
inband spectral shaping as defined by the values of REDUCED_PSD_lowband, PSD level at
1622 kHz, and PSD level at 2208 kHz
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied in the passband below 1104 kHz. It is coded in steps of 0.125dB
relative to NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40
dBm/Hz; 00001101 means -41.625 dBm/Hz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 1622 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the REDUCED_PSD_lowband level at 1104 kHz and the PSD level at 1622 kHz.
This 8 bit Npar(3) parameter indicates the relative downstream PSD level that the ATU-R
wishes to have applied at 2208 kHz. It is coded in steps of 0.125dB relative to
NOMINAL_PSD_lowband (–40dBm/Hz). For example, 00000000 means –40 dBm/Hz;
00001101 means -41.625 dBm/Hz. The PSD level shall be linearly interpolated in dBs
between the PSD level at 1622 kHz and the PSD level at 2208 kHz.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing extended upstream
operation.
If set to ONE, this Npar(3) bit indicates that the ATU-R is proposing upstream PSD mask
US-xx. For non-overlapped spectrum, extended upstream masks are associated withdownstream masks according to Figure I.13. For overlapped spectrum, any EU-xx may be
used with the overlapped downstream spectrum specified in §I.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode 1(different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode 2(same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing one of the optional
upstream masks when using non-overlapped spectrum downstream.

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum
Note 1: More than one pilot tone bit may be set in an MP message.

I.7.4

Transceiver Training – ATU-C (supplements 10.4)

During transceiver training from C-REVERB1 to C-SEGUE1 except C-PILOTn and C-QUIETn, the ATU-C shalltransmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), and shall not transmit
the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state isdefined as Figure I.26.
I.7.4.1

C-PILOT1 (supplements 10.4.2)

The ATU-C shall start the NSWF (sliding window frame) counter from 0 immediately after entering C-PILOT1, andincrement the NSWF counter modulo 345 after transmission of each DMT symbol. According to the sliding windowfunction and this counter, the ATU-C decides to transmit all of the subsequent symbols in either FEXTR or NEXTR
symbols (for example, see Figures I.11, I.19 and I.24).
C-PILOT1 has two signals.
The first signal is the pilot tone, a single frequency sinusoid at fC-PILOT1 defined as:- 382 -

⎧
Xk = ⎨⎩

0, k ≠ nC − PILOT 1 , 0 ≤ k ≤ NSC
AC − PILOT 1 , k = nC − PILOT 1

The frequency of the pilot tone shall be selected from one of the following choices during G.994.1 as:
20. fC-PILOT1 = 276 kHz (nC-PILOT1 = 64).
21. fC-PILOT1 = 414 kHz (nC-PILOT1 = 96).
22. fC-PILOT1 = 552 kHz (nC-PILOT1 = 128).
23. fC-PILOT1 = 1104 kHz (nC-PILOT1 = 256).
Transmitters that support Annex I-EU shall support all of these pilot tones.
The second signal is the TTR indication signal used to transmit NEXTR/FEXTR information. The ATU-R can detect
the phase information of the TTRC from this signal. The TTR indication signal shall be selected during G.994.1 as:
A48 signal –the constellation encoding of the 48th carrier with 2-bit constellation as follows:(+ , +) to indicate a FEXTR symbol;(+ , –) to indicate a NEXTR symbol.
I.7.4.2

C-PILOT1A (supplements 10.4.3)

C-PILOT1A has two signals and it is the same transmitted signal as C-PILOT1 (C.7.4.1).
I.7.4.3

C-REVERB3 (supplements 10.4.11)

In order to synchronize the first symbol of C-RATES1 with the beginning of the hyperframe and to inform the enteringtiming of C-RATES1 to the ATU-R, the first symbol of C-SEGUE1 shall be transmitted inside of the FEXTR duration
as shown in Figure I.22. Therefore, the duration of C-REVERB3 is 3628 DMT symbols.

TTRC
20 symbols
C-SEGUE1

C-REVERB3

C-RATES1

the time of the detection
C-SEGUE1

R-REVERB3
T1532880-99

Figure I.22/G.992.1 – Timing diagram from C-SEGUE1 to C-RATES1

I.7.4.4

C-REVERB1 (replaces 10.4.5)

C-REVERB1 is a signal that allows the ATU-C and ATU-R receiver to adjust its automatic gain control (AGC) to an
appropriate level. The data pattern used in C-REVERB1 shall be the pseudo-random downstream sequence (PRD), dn
for n = 1 to 2*NSCds, defined in I.4.7.5 and repeated here for convenience:dn = 1dn = dn-4 ⊕ dn-9

for n = 1 to 9
for n = 10 to 2*NSCds- 383 -

(10-1)

The bits shall be used as follows: the first pair of bits (d1 and d2) is used for the DC and Nyquist subcarriers (the powerassigned to them is, of course, zero, so the bits are effectively ignored); then the first and second bits of subsequentpairs are used to define the Xi and Yi for i = 1 to NSCds-1 as defined in Table 7-13.
The period of PRD is only 511 bits, so dn+511 is equal to dn. The bits d1 to d9 shall be re-initialized for each symbol,
so each symbol of C-REVERB1 is identical.
The two bits that modulate the pilot carrier shall be overwritten by {0,0}: generating the {+,+} constellation.
The duration of C-REVERB1 is 512 (repeating) symbols without cyclic prefix.
I.7.4.4.1

Power Cut-back (supplements 10.4.5.1)

For Annex I-EU, see A.3.1.

I.7.5

Transceiver Training – ATU-R (supplements 10.5)

During transceiver training from R-REVERB1 to R-SEGUE1 except R-QUIETn, the ATU-R shall transmit both
FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC
symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is defined as Figure I.26.
I.7.5.1

R-QUIET2 (supplements 10.5.1)

The ATU-R enters R-REVERB1 after it completes timing recovery and Hyperframe synchronization from
C-PILOT1/C-PILOT1A.
I.7.5.2

R-REVERB1 (supplements 10.5.2)

The data pattern used in R-REVERB1 is the pseudo-random upstream sequence PRU defined in 8.11.3, repeated asnecessary for the selected NSCus:⎧⎪d n = 1⎨⎪⎩d n = d n −5

for n = 1 to 6
⊕ d n − 6 for n = 7 to 64(C.10-1)

The period of PRU is only 63 bits, so dn+63 is equal to dn.
The ATU-R shall start its NSWF counter immediately after entering R-REVERB1, and then increment the NSWF
counter with modulo 345 from 0 when it transmits each DMT symbol. The ATU-C and ATU-R shall have the samevalue since hyperframe alignment between the ATU-C and ATU-R shall be maintained. According to the sliding
window and this counter, the ATU-R decides to transmit all of the subsequent symbols in either the FEXTC or the
NEXTC symbol.
I.7.5.3

R-QUIET3 (replaces 10.5.3)

The final symbol of R-QUIET3 accommodates the frame alignment of the transmitter to that of the receiver. It may be
shortened by any number of samples. The maximum duration of R-QUIET3 is 6145 DMT symbols.
I.7.5.4

R-REVERB2 (supplements 10.5.5)

After ATU-R detects C-SEGUE1, the ATU-R enters R-SEGUE1. The maximum duration of R-REVERB2 is 3643
DMT symbols.
I.7.6

Channel analysis (ATU-C) (supplements 10.6)

ATU-C shall transmit only FEXTR symbols, and shall not transmit the NEXTR symbols except the pilot tone from- 384 -

C-RATES1 to C-CRC2. During C-MEDLEY, the ATU-C shall transmit both FEXTR and NEXTR symbols when
Bitmap-NR is enabled (Dual Bitmap mode). The ATU-C shall not transmit NEXTR symbols except the pilot tone,
when Bitmap-NR is disabled (FEXT Bitmap mode). The duration of each state is defined in Figure I.26.
I.7.6.1

C-SEGUE1 (supplements 10.6.1)

The duration of C-SEGUE1 is 20 symbols in order that the first symbol of C-SEGUE1 shall be inside of the FEXTR
duration.

- 385 -

I.7.6.2

C-MEDLEY (replaces 10.6.6)

C-MEDLEY is a wideband pseudo-random signal used for estimation at the ATU-R of the downstream SNR. The data
to be transmitted are derived from the pseudo-random sequence, PRDm, defined as:
d n = 1 for n = 1 to 14 and d n = d n-5 ⊕ d n-11 ⊕ d n-12 ⊕ d n-14 for n> 14,
and modulated as defined in 10.4.5. In contrast to C-REVERB1, the cyclic prefix is used and the data sequence
continues from one symbol to the next (i.e. d1 to d14 are not re-initialized for each symbol). Because the sequence is oflength 214-1, and far fewer bits are used for each symbol, the subcarrier vector for C-MEDLEY changes from one
symbol period to the next. For non-overlapped spectrum, 2*(512-mm+1) bits are used each symbol, where mm is theminimum subcarrier specified for PSD mask DS-mm in Table I.13. For overlapped spectrum, 2*507 bits are used eachsymbol. The pilot subcarrier is overwritten by the (+,+) signal constellation. The duration of C-MEDLEY is as shown in
Figure I.26. Following C-MEDLEY the ATU-C shall enter the state C-REVERB4.
With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure I.23. The ATU-C
transmits the signal in both of NEXTR and FEXTR symbols, and the ATU-R estimates two SNRs from the received
NEXTR and FEXTR symbols, respectively, as defined in Figure I.24.
The following formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > d) }if { (S > b) and (S + 271 < c) }where a = 1243, b = 1403, c = 2613, d = 2704

then symbol for estimation of FEXTR SNR
then symbol for estimation of NEXTR SNR

When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbol. The
number of bits of NEXTR shall be no more than the number of bits of FEXTR.
At the transmitter, the PRDm sequence generator shall continue to be updated during NEXTR symbols when BitmapNR is disabled (FEXT Bitmap mode).

- 386 -TTR
TCM-ISDN crosstalkat ATU-R receiver

TCM-ISDN crosstalkat ATU-C receiver

NEXT

NEXT

FEXT

FEXT

FEXT

NEXT

NEXT

NEXT

FEXT

FEXT
Estimation of
Signal-to-Noise ratio

C/R-MEDLEY (49152 symbols)

Bitmap for Downstream

Bitmap-NR

Bitmap-FR

Bitmap-FR

Bitmap-NR

Bitmap for Upstream

Bitmap-FC

Bitmap-NC

Bitmap-NC

Bitmap-FC
T1532890-99

Figure I.23/G.992.1 – Estimation of periodic Signal-to-Noise Ratio- 387 -

TTRC
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

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8

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100

101

10 101

102

103

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108

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11

112

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122

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13

132

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15

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18

183

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31

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32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

Symbol for estimation of FEXTR S/N
Symbol for estimation of NEXTR S/N

Symbol not used for S/N estimation
T1535370-00

Figure I.24/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Downstream

I.7.6.3

C-RATES1 (supplements 10.6.2)

In order to support data rates greater than 16 Mbit/s, the BI field has 10 bits. The RRSI fields shall use the same
extended syntax as defined in I.7.9.4 for C-RATES-RA.
For the S=1/2n framing mode (see §I.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,- 388 -RSI = RI/(n*S).
I.7.6.4

C-MSG1 (supplements 10.6.4)

Table I.13/G.992.1 – Assignment of 48 bits of C-MSG1
Suffix(ces) of mi (Note 1)
Parameter (Note 3)
47-44
Minimum required downstream SNR margin at initialization (Note 2)
43-18
Reserved for future use
17
Trellis coding option
16
Overlapped spectrum option (Note 4)
15
Unused (shall be set to "1")
14-12
Reserved for future use
11
NTR
10-9
Framing mode
8-6
Transmit PSD during initialization
5
Reserved
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – A positive number of dB; binary coded 0-15 dB.
NOTE 3 – All reserved bits shall be set to "0".
NOTE 4 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
I.7.6.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.6.4.8)

The Ndownmax (transmit) capability shall be binary encoded onto {m4, ..., m0} (e.g. 100012 = 17). The maximum
number of bits for the upstream data, Nupmax, that the ATU-C receiver can support need not be signalled to the ATU-R;
it will be implicit in the bits and gains message, C-B&G, which is transmitted after channel analysis.
I.7.7

Channel analysis (ATU-R) (supplements 10.7)

From R-RATES1 to R-CRC2, the ATU-R shall transmit only the FEXTC symbols and shall not transmit the NEXTC
symbols. In R-SEGUE2 and R-MEDLEY, the ATU-R shall transmit both FEXTC and NEXTC symbols when
Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC symbols when Bitmap-NC is disabled(FEXT Bitmap mode). The duration of each state is defined in Figure I.26.
I.7.8

R-SEGUE1 (supplements 10.7.1)

The maximum duration of R-SEGUE1 is 14 symbols (see Figure I.22).
I.7.8.1

R-REVERB3 (supplements 10.7.2)

The ATU-R shall start R-REVERB3 aligned with the beginning of a Hyperframe.
I.7.8.2

R-SEGUE2 (supplements 10.7.3)

The duration of R-SEGUE2 is 13 symbols.
I.7.8.3

R-MEDLEY (replaces 10.7.8)

R-MEDLEY is a wideband pseudo-random signal used for estimation of the upstream SNR at the ATU-C. The data to
be transmitted are derived from the pseudo-random sequence PRUm defined as:
d n = 1 for n = 1 to 23 and d n = d n-18 ⊕ d n-23 for n> 23.
In contrast to R-REVERB1, the cyclic prefix is used and the data sequence continues from one symbol to the next (i.e.
d1 to d23 are not re-initialized for each symbol). Because the sequence is of length 223-1, and 2*(nn-5) bits are used for- 389 -

each symbol (where nn is the maximum subcarrier specified for PSD mask EU-nn in Table I.18), the subcarrier vector
for R-MEDLEY changes from one symbol period to the next. Following R-MEDLEY the ATU-R enters signalling state
R-REVERB4. The duration of R-MEDLEY is as shown in Figure I.26.
With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure I.23. ATU-R shalltransmit the signal in both of NEXTC and FEXTC symbols, and ATU-C shall estimate two SNRs from the received
NEXTC and FEXTC symbols, respectively, as defined in Figure I.25.
The following numerical formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > b) and (S + 271 < c) }if { (S + 271 < a) }where a = 1148, b = 1315, c = 2608

then symbol for estimation of FEXTC SNR
then symbol for estimation of NEXTC SNRWhen Bitmap-NC is disabled (FEXT Bitmap mode), the ATU-R shall not transmit NEXTC symbol. The number of bitsof NEXTC shall be no more than the number of bits of FEXTC.
At the transmitter, the PRUm sequence generator shall continue to be updated during NEXTC symbols when BitmapNC is disabled (FEXT Bitmap mode).

- 390 -

TTR R
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

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21

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6

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7

71

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8

81

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9

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11
12

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135

136

137

138

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306

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309

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314

315

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321

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31
32

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329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

T1535290-00

Symbol for estimation of FEXT C S/N

Symbol not used for S/N estimation

Symbol for estimation of NEXT C S/N

Figure I.25/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Upstream

I.7.8.4

R-MSG1 (supplements 10.7.6)- 391 -

Table I.14/G.992.1 – Assignment of 48 bits of R-MSG1
Parameter (Note 2)
Suffix(ces) of mi (Note 1)
47-18
Reserved for future use

17
Trellis coding option
16
Overlapped spectrum option (Note 3)
15
Unused (shall be set to "1")14
Support of S = 1/2 mode (see I.4.9) (Note 4)
13
Support of dual latency downstream
12
Support of dual latency upstream
11
Network Timing Reference
10, 9
Framing mode
8-5
Reserved for future use
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
NOTE 3 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
NOTE 4 – Since the S=1/2 mode is mandatory for Annex I-EU, a modem supporting Annex I-EU shall set this bit tobinary ONE.

I.7.8.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.7.6.6)

The Nupmax (transmit) capability is encoded onto {m4 , ..., m0} with a conventional binary representation (e.g.
100012 = 17).
I.7.9

Exchange – ATU-C (supplements 10.8)

During C-RATESn, C-MSGn, C-B&G, and C-CRCn, the ATU-C shall transmit the FEXTR symbol. In the other signals,
the ATU-C shall transmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), andshall not transmit the NEXTR symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). The
duration of each state is defined in Figure I.27.
I.7.9.1
C-MSG2 (supplements 10.8.9)
Replace Table 10-13 with Table I.15.

Table I.15/G.992.1 – Assignment of 32 bits of C-MSG2
Suffix(ces) of mi (Note 1)

Parameter (Note 2)

31-26

Estimated average loop attenuation

25-21

Reserved for future use

20-16

Performance margin with selected rate option

15-11

Reserved for future use

10-0

Total number of bits supported

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
For NSCus=32,
n1C-MSG2 = 43
n2C-MSG2 = 91

- 392 -

Otherwise,
n1C-MSG2 = 139
n2C-MSG2 = 187
I.7.9.1.1

Total number of bits per symbol supported (replaces 10.8.9.3)

The ATU-C receiver shall also calculate the maximum number of bits per symbol that the upstream channel can support−7

with the performance margin defined in C-MSG-RA at an error rate of 10 .
The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTC and
NEXTC downstream channel performance [e.g. if the maximum numbers of bits that can be supported in FEXTC and
NEXTC symbols are 111 and 88 {Total number of bits per symbol supported} = (111 x 126 + 88 x 214)/340 = 96]. This
number is encoded into bits 10-0 using a conventional binary representation [e.g. if the maximum number of bits thatcan be supported is 96 (data rate = 384 kbit/s), {m10, ..., m0} = 000011111112].
NOTE – The number of symbols per hyperframe is 340. The number of FEXT symbols is 126. The number of NEXTsymbols is 214.
I.7.9.1.2

Estimated average upstream loop attenuation (supplements 10.8.9.1)

For Annex I-EU, see A.3.2.

I.7.9.2

C-B&G (replaces 10.8.13)

C-B&G shall be used to transmit to the ATU-R the bits and gains information, Bitmap-FC {b1, g1, b2, g2, ... bNSCus-1,
gNSCus-1}, and Bitmap-NC {b NSCus+1, g NSCus+1, b NSCus+2, g NSCus+2, ..., b2*NSCus-1, g2*NSCus-1}, thatare to be used on the upstream carriers. bi of Bitmap-FC indicates the number of bits to be coded by ATU-R transmitter
onto the i th upstream carrier in FEXTC symbols; gi of Bitmap-FC indicates the scale factor, relative to the gain thatwas used for that carrier during the transmission of R-MEDLEY, that shall be applied to the i th upstream carrier in
FEXTC symbols. Similarly, bi of Bitmap-NC indicates the number of bits onto the (i – NSCus) th upstream carrier in
NEXTC symbols; gi of Bitmap-NC indicates the scale factor that shall be applied to the (i – NSCus) th upstream carrierin NEXTC symbols.
Because no bits or energy will be transmitted at DC or one-half the sampling rate, b0, g0, bNSCus, gNSCus, b2*NSCus,
and g2*NSCus are all presumed to be zero and shall not be transmitted.
Each bi shall be represented as an unsigned 5-bit integer, with valid bis lying in the range of zero to Nupmax, themaximum number of bits that the ATU-R is prepared to modulate onto any subcarrier, which is communicated in
R-MSG1.
Each gi shall be represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of
the third most significant bit. For example, a gi with binary representation (most significant bit listed first)
001.010000002 would instruct the ATU-R to scale the constellation for carrier i, by a gain factor of 1.25, so that thepower in that carrier shall be 1.94 dB higher than it was during R-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
Let NSCu=128, except when EU-32 is used where NSCu=32. The C-B&G information shall be mapped in a32*(NSCu-1)-bit (4*(NSCu-1) byte) message m defined by:- 393 -

m = {m32*(NSCu-1)-1, m32*(NSCu-1)-2, …, m1, m0} = { g2*NSCu-1, b2*NSCu-1, …, g NSCu+1, b NSCu+1, g(C.10-2)
NSCu-1, b NSCu-1, …, g1, b1},
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in
4*(NSCu-1) FEXTR symbols. When NSCu=32, including C_CRC5, the total length is 336 symbols while for
NSCu=128, the total length is 336+3*345=1371 symbols, using the transmission method as described in 10.8.9.
When Bitmap-NC is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NC shall be set to zero.
For index between NSCus+1 and 127, the m values are set to 0.

I.7.9.3

C-SEGUE3 (replaces 10.8.16)

The duration of C-SEGUE3 is 18 symbols. Following C-SEGUE3, the ATU-C completes the initialization and enters
C-SHOWTIME. In C-SHOWTIME, ATU-C shall transmit the signal using Bitmap-FR and Bitmap-NR with the sliding
window.
When Bitmap-NR is disabled (FEXT Bitmap mode), ATU-C shall transmit only the pilot tone as NEXTR symbols.
I.7.9.4

C-RATES-RA (supplements 10.8.3)
Table I.16/G.992.1 – RRSI fields of C-RATES-RA←⎯⎯⎯⎯⎯ bits ⎯⎯⎯⎯→
fields

7

6

RSF

0

0

5

4

3

2

1

value of RSF
MSB

RSI

B8 (AS0)LSB

B9 (AS0)

value of RSI
MSB

S

I9

LSB

I8

value of S
MSBIFS(LS2)

I7

I6

0

I5

LSB
I4

I3

I2

I1

I0

value of FS(LS2) set to {000000002}

The RSI field has been extended to include the most significant bit B9 of BI (AS0), the number of payload bytes in theAS0 bearer channel in the downstream interleave buffer, in bit 6. This is to support the higher data rates for the optional
S=1/4 and S=1/3 modes.
The S field shall be coded {1001002) to indicate S=1/4.
For the S=1/2n framing mode (see §I.4.9), the downstream RSI shall be the number of parity bytes per sync byte, i.e.,
RSI = RI/(n*S).

- 394 -

I.7.10

Exchange – ATU-R (supplements 10.9)

ATU-R shall transmit only the FEXTC symbols in R-MSGn, R-RATESn, R-B&G, R-CRCn. In other signals, the
ATU-R shall transmit both FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shallnot transmit NEXTC symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is definedin Figure I.27.
I.7.10.1

R-MSG-RA (supplements 10.9.2)

Replace Table 10-15 with Table I.17.

Table I.17/G.992.1 – Assignment of 80 bits of R-MSG-RA (Annex I-EU)
Suffix(ces) of mi(Note)
79-71
70
69, 68
67-56

Parameter
All reserved bits shall be set to 0
Reserved for ITU-T
Extension to number of RS payload bytes, K
Extension to number of tones carrying data (ncloaded)
Bfast-max

55-49
48-40
39-32
31-25
24-21
20-16
15
14

Number of RS overhead bytes, (R)
Number of RS payload bytes, K
Number of tones carrying data (ncloaded)
Estimated average loop attenuation
Coding gain
Performance margin with selected rate option
Reserved for ITU-T
Extension to total number of bits per DMT symbol, Bmax

13-12
11-0

Maximum Interleave Depth downstream
Total number of bits per DMT symbol, Bmax

NOTE – Within the separate fields the least significant bits have the lowest subscripts.

I.7.10.1.1

Total number of bits supported (Bmax) (replaces 10.9.2.8)

This parameter shall be defined as in R-MSG2, see I.7.9.1.
I.7.10.1.2

Bfast-max (new)Bfast-max is the maximum number of bits of the fast buffer for fast data transmitted on the condition that the bits of thefast data can be equally assigned to all FEXT-symbols and NEXT-symbols.
Fast Buffered Data Bfast-max is tf.
I.7.10.2

R-MSG2 ( supplements 10.9.8)- 395 -

Suffix(ces) of mi (Note 1)
31-25
24-21
20-16
15
14
13-12
11-0

Table I.18/G.992.1 – Assignment of 32 bits of R-MSG2
Parameter (Note 2)
Estimated average loop attenuation
Reserved for future use
Performance margin with selected rate option
Reserved for future use
Extension to total number of bits per DMT symbol, Bmax
Reserved for future use
Total number of bits per DMT symbol, Bmax

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
N1R-MSG2 = 10
N2R-MSG2 = 20
I.7.10.2.1

Total number of bits per symbol supported (supplements 10.9.8.3)

The maximum number of bits per symbol that the downstream channel can support is encoded into bits 14 and 11 – 0.
The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTR and
NEXTR downstream channel performance. For example, if the maximum numbers of bits that can be supported in
FEXTR and NEXTR symbols are 111 and 88, the total number of bits per symbol supported is (111 x 126 + 88 x
214)/340 = 96.
NOTE – The number of symbols per hyperframe is 340, the number of FEXT symbols is 126, and the number of NEXTsymbols is 214.
I.7.10.2.2

Estimated average downstream loop attenuation (supplements 10.9.8.1)

For Annex I-EU, see A.3.3.
I.7.10.3 R-REVERB5 (supplement of 10.9.12)
The duration of R-REVERB5 is 345n-40, 3<=n<=19, when NSCu=128, or 3<=n<=16 when NSCu=32.
I.7.10.4

R-B&G (replaces 10.9.14)

The purpose of R-B&G is to transmit to ATU-C the bits and gains information, Bitmap-FR {b1, g1, b2, g2, ...,bNSCds-1, gNSCds-1}, and Bitmap-NR {bNSCds+1, gNSCds+1, bNSCds+2, gNSCds+2, ..., b2*NSCds-1,
g2*NSCds-1}, to be used on the downstream subcarriers. bi of Bitmap-FR indicates the number of bits to be coded by
ATU-C transmitter onto the i th downstream subcarrier in FEXTR symbols; gi of Bitmap-FR indicates the scale factor
that shall be applied to the i th downstream subcarrier in FEXTR symbols, relative to the gain that was used for thatcarrier during the transmission of C-MEDLEY. Similarly, bi of Bitmap-NR indicates the number of bits onto the (i –NSCds) th downstream carrier in NEXTR symbols; gi of Bitmap-NR indicates the scale factor that shall be applied tothe (i – NSCds) th downstream carrier in NEXTR symbols. Because no bits or energy will be transmitted at DC or
one-half the sampling rate, b0, g0, bNSCds, gNSCds, b2*NSCds, and g2*NSCds are all presumed to be zero, and are
not transmitted. When subcarrier 64 is reserved as the pilot tone, b64 and bNSCds+64, shall be set to 0, g64 andgNSCds+64 shall be set to gsync. When subcarrier 128 is reserved as the pilot tone, b128 and bNSCds+128, shall be set
to 0, g128 and gNSCds+128 shall be set to gsync. When subcarrier 256 is reserved as the pilot tone, b256 andbNSCds+256, shall be set to 0, g256 and gNSCds+256 shall be set to gsync. The value gsync represents the gain scaling
applied to the sync symbol.
Each bi is represented as an unsigned 5-bit integer, with valid bi lying in the range of zero to Ndownmax, the maximum- 396 -

number of bits that the ATU-C is prepared to modulate onto any subcarrier, which is communicated in C-MSG1.
Each gi is represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of thethird most significant bit. For example, a gi with binary representation (most significant bit listed first) 001.010000002
would instruct the ATU-C to scale the constellation for carrier i by a gain factor of 1.25, so that the power in that carrier
shall be 1.94 dB higher than it was during C-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
The R-B&G information shall be mapped in a (2*NSCds-2)*16-bit ((2*NSCds-2)*2 byte) message m defined by:
m = {m(2*NSCds-2)*16-1, m(2*NSCds-2)*16-2, …, m1, m0} = { g2*NSCds-1, b2*NSCds-1, …, g NSCds+1, b(I.10-3)
NSCds+1, g NSCds-1, b NSCds-1, …, g1, b1},
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in(2*NSCds-2)*2 symbols, using the transmission method as described in 10.9.8.
When Bitmap-NR is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NR shall be set to zero.

- 397 -

I.7.10.5

R-SEGUE5 (replaces 10.9.17)

The duration of R-SEGUE5 is 13 symbols. Following R-SEGUE-5, ATU-R completes the initialization and enters
R-SHOWTIME. In R-SHOWTIME, ATU-R shall transmit the signal using Bitmap-FC and Bitmap-NC with the sliding
window.
When Bitmap-NC is disabled (FEXT Bitmap mode), ATU-R shall not transmit NEXTC symbols.
ATU-C
C-FLAG2(G.994.1)

C-GALF2(G.994.1)≥ 128≤ 2048C-QUIET2(Note 5)345n(n ≤ 38)

ATU-R

If R-ACK2then
C-PILOT1

If R-ACK1then
C-PILOT1AR-GALF2(G.994.1)

Beginning ofHyperframe

R-QUIET2≤ 15500

345n(1 ≤ n ≤ 33)≤ 32
Beginning ofHyperframe

1725

C-QUIET3A(Note 2)

R-FLAG2(G.994.1)

R-REVERB1
1536

C-REVERB1
12477(Note 5)9216

C-PILOT2(Note 4)

1536

C-ECT

(Note 2)

(Note 5)4608

C-REVERB2

1536

If R-ACK2 then C-PILOT3
If R-ACK1 then C-QUIET53628

C-REVERB3

20

C-SEGUE1

2884

C-RATES1/C-CRC1
C-MSG1/C-CRC2

Last symbol
may beshortened byn samples

R-QUIET3≥ 6144≤ 6145

R-ECT

1536

R-REVERB2≥ 3634≤ 3643

R-SEGUE1

5 ≤, ≤ 14(Note 2)

(Note 1)Introduction ofguard time

R-REVERB3
345n + 208(0 ≤ n ≤ 7)

49152
C-MEDLEY

345n - 13(9 ≤ n ≤ 16)
R-SEGUE2

13

R-RATES1/R-CRC1
R-MSG1/R-CRC2

1254

R-MEDLEY

49152(Note 3)(Note 2)

T1532900-99

Figure I.26/G.992.1 – Timing diagram of the initialization sequence – Part 1- 398 -

(Note 4)NOTE 1 – The ATU-C shall transmit the FEXTR symbols, and shall not transmit as NEXTR symbols except the pilot
tone.
NOTE 2 – The ATU-C shall transmit both FEXTR and NEXTR symbols, when Bitmap-NR is enabled (Dual Bitmapmode). ATU-C shall not transmit the NEXTR symbols except pilot tone, when Bitmap-NR is disabled(FEXT Bitmap mode).
NOTE 3 – The ATU-R shall transmit the FEXTC symbols, and shall not transmit the NEXTC symbols.
NOTE 4 – The ATU-R shall transmit both FEXTC symbols, when Bitmap-NC is enabled (Dual Bitmap mode).
ATU-R shall not transmit NEXTC symbols, when Bitmap-NC is disabled (FEXT Bitmap mode).

- 399 -NOTE 5 – The ATU-C shall transmit both FEXTR and NEXTR symbols.
Figure I.27/G.992.1 – Timing diagram of the initialization sequence – Part 2[Editor’s note: updated Figure I.27 to parameterize the length of C-B&G and the maximum length of R-REVERB5.]
I.8
I.8.1.1

AOC On-line adaptation and reconfiguration (pertains to clause 11)
Bit swap request (replaces 11.2.3)

The receiver shall initiate a bit swap by sending a bit swap request to the transmitter via the AOC channel. This request
tells the transmitter which subcarriers are to be modified. The format of the request is shown in Table I.19.

Table I.19/G.992.1 – Format of the bit swap request message
Message header{111111112}(8 bits)

Bitmap index(1 bit)Message field 1-4
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

The request shall comprise nine bytes as follows:• an AOC message header consisting of 8 binary ones;• message fields 1-4, each of which consists of a one-bit bitmap index, subchannel index bits 10 & 9, and a five-bit
command followed by bits 8 to 1 of the subchannel index. One-bit bitmap index, subchannel index bits 10 & 9,
and valid five-bit commands for the bit swap message shall be as shown in Table I.20. In Table I.20, the MSB
for the bit swap request command represents the Bitmap index. For downstream data, Bitmap index equals 0
indicates Bitmap-FR, and Bitmap index equals 1 indicates Bitmap-NR. Similarly for upstream data, Bitmap
index equals 0 indicates Bitmap-FC, and 1 indicates Bitmap-NC. The next 2 bits are subchannel index bits 10 &9. The ten-bit subchannel index is counted from low to high frequencies with the lowest frequency subcarrier
having the number zero. The subcarrier index zero shall not be used;• the bit swap between FEXTC/R symbols and NEXTC/R symbols is not allowed.

- 400 -

Table I.20/G.992.1 – Bit swap request commandValue(8 bit)yzz000002

Interpretation
Do nothing

yzz000012
yzz000102

Increase the number of allocated bits by one

yzz000112
yzz001002

Increase the transmitted power by 1 dB

yzz001012
yzz001102

Increase the transmitted power by 3 dB

yzz001112
yzz01xxx2

Reduce the transmitted power by 2 dB

Decrease the number of allocated bits by one
Increase the transmitted power by 2 dB
Reduce the transmitted power by 1 dB
Reserved for vendor discretionary commands

NOTE – y is "0" for FEXTC/R symbols, and "1" for NEXTC/R symbols of the Sliding Window.
NOTE – subchannel index = zz2*256 + subchannel index value from lower 8 bit field
The bit swap request message (i.e. header and message fields) shall be transmitted five consecutive times.
To avoid gi divergence between ATU-C and ATU-R after several bit swaps, for a gi update of ∆ dB the new gi value
should be given by:

g i ' = (1 / 256) × round (256 × g i × 10 exp(∆ / 20))I.8.1.2(I.11-1)

Extended bit swap request (supplements 11.2.4)

The format of the extended bit swap request is shown in Table I.21.

Table I.21/G.992.1 – Format of the bit swap request message
Message header{111111002}(8 bits)

Bitmap index(1 bit)Message field 1-6
Subchannel
Commandindex – bits 10 (5 bits)&9(2 bits)

Subchannel
index – bits 8
to 1(8 bits)

In the same manner as the bit swap request, each of the message fields of the extended bit swap request consists of
one-bit bitmap index, a five-bit command followed by a related ten-bit subchannel index.
I.8.1.3

Bit swap acknowledge (supplements 11.2.5)

The bit swap superframe counter number shall only indicate the last superframe (SPF#4) of a hyperframe.
The new bit and/or transmit power table(s) shall then take effect starting from the first frame (frame 0) of SPF#0 of a
hyperframe.
If the bit swap superframe counter number contained in the received bit swap acknowledge message does not indicate
SPF#4, then the new table(s) shall take effect starting from frame 0 of SPF#0 of the next hyperframe.
I.9

POTS splitter

For operation according to G.992.1 Annex I-EU, the Annex E.4/G.992.3 requirements applying over a frequency band
up to 1104 kHz, shall be met over a frequency band up to 2208 kHz.

- 401 -

資料７
G.992.1 ANNEX C-EU (REVISION 1)
PROPRIETARY EXTENSION TO G.992.1 ANNEX C

This document defines G.992.1 Annex C-EU (Single spectrum downstream with extended upstream spectrum), a
proprietary extension to G.992.1 Annex C to extend the data rate beyond 2 Mbit/s upstream by way of:• Increase upstream bandwidth Æ increased number of subcarriers, NSCus=64• Increased bit loading, beyond 15 bits/bin• Two new extended reach PSD masks LD-TIF1&2 added.
Due to the increase in upstream data rates, the upstream maximum interleave depth has been increased to 16. Support ofthis is mandatory.
The attached text is the approved text for Annex C, marked up with revision control to show the changes necessary tosupport the additional functionality.
Revision 1 text is based on G.992.1 Annex I-EU Revision 1, and supports the following features:• extended upstream to subcarrier 64• high bit loading (HBL),• overlapped spectrum,• D=16 upstream mandatory
Still to do:• add the DS PSD masks (done) and code points for LD-TIF1 and 2 (done)• (for each profile with extended upstream: no change in pilot tone and TTR indication signal - done
• C-MSG2 subcarriers for signalling: 91 and 139 - done
• go through the document and renumber tables and figures to fix the numbering after adding the newtables/figures.
• Modified timing diagram for initialization in Figure C.22(C-B&G and R-REVERB5 text has been changed.
Update Figure C.22 later) -done- 402 -

ANNEX C-EU
Specific requirements for an ADSL system to support upstream data rates greater than 2 Mbit/s operating in thesame cable as ISDN
as defined in ITU-T Recommendation G.961 Appendix III

C.1

Scope

This annex describes those specifications that are unique to an ADSL system coexisting in the same binder as
TCM-ISDN as defined Recommendation G.961 Appendix III. The subclauses in this annex provide supplementary andreplacement material to the clauses in the main body. The nature of the material is parenthetically indicated in the
subclause heading. The modifications described in this annex allow a performance improvement from the ADSL system
specified in Annex A in an environment coexisting with TCM-ISDN in the same cable. Specifically, this Annex
specifies extensions to upstream bandwidth and maximum bit loading to support upstream data rates greater than 2
Mbit/s. This annex also defines those parameters of this ADSL system that have been left undefined in the main body ofthis Recommendation. An ADSL system implementing Annex C-EU shall support Annex C. It is recommended that an
ADSL system implementing Annex C-EU also implements Annex A.
This Amendment defines several optional operating modes or “profiles”, negotiable through G.994.1, to allow limited
independent control of:• FEXT and NEXT period transmission in both upstream and downstream directions• overlapped and non-overlapped spectrum downstream during FEXT and NEXT periods
These new optional profiles (defined in Section § C.3.4 as Profiles 1 to 6) offer improved robustness and extended reachcompared to the previously defined operating modes.
C.2

Definitions

Bitmap-FC
Bitmap-FR
Bitmap-NC
Bitmap-NR
Dual Bitmap
FEXT Bitmap
FEXTC duration
FEXTC symbol
FEXTR duration
FEXTR symbol
Hyperframe
NEXTC duration
NEXTC symbol
NEXTR duration
NEXTR symbol
NSCus
NSWF
Subframe
TTR
TTRC
TTRR
UI
C.3

ATU-R transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-R
ATU-R transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-C
ATU-C transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-R
The Dual Bitmap method has dual bit rates under the FEXT and NEXT noise from TCM-ISDN
Similar to the Dual Bitmap method however transmission only occurs during FEXT noise fromTCM-ISDN
TCM-ISDN FEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN FEXTTCM-ISDN FEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN FEXT
5 Superframes structure which synchronized TTR
TCM-ISDN NEXT duration at ATU-C estimated by the ATU-R
DMT symbol transmitted by ATU-R during TCM-ISDN NEXT
TCM-ISDN NEXT duration at ATU-R estimated by the ATU-C
DMT symbol transmitted by ATU-C during TCM-ISDN NEXT
The highest subcarrier index that can be used for upstream transmission (i.e., the subcarrier
index corresponding to the Nyquist frequency) For example, NSCus = 64 for an upstream
channel using the frequency band up to 276 kHz.
Sliding Window frame counter10 consecutive DMT symbols (except for sync symbols) according to TTR timing
TCM-ISDN Timing Reference
Timing reference used in ATU-C
Timing reference used in ATU-R
Unit Interval

Reference Models- 403 -

C.3.1ATU-C transmitter reference model (replaces figures in 5.1)

See Figure C.1 and Figure C.2.

"Bits""Bits" &"Gains"
511

AS0
AS1
AS2
AS3

crcf
Mux/
Sync
Control

LS0
LS1
LS2
NTR

crci

scram
&
FEC

scram
&
FEC

Rate
converterInterleaver

Rate
converterToneordering

Constellation
encoderandgainscaling

510
480
IDFT

OutputParallel/
SerialBuffer

1
n=0

OAM

TTR

DAC and Analogue
processing

EOC/
AOC ib

V-C
Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to 255
Constellation
Encoder Input
Data Frame

U-C

T1532760-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure C.1/G.992.1 – ATU-C transmitter reference model for STM transport
Annex C-EU does not currently support STM transport. It only supports ATM transport.

- 404 -

"Bits""Bits" &"Gains"
511

AS0
ATM0

Cell TC
crcf

AS1
ATM1

Cell TC

NTR

Mux/
Sync
Control
crci

scram
&
FEC

scram
&
FEC

Rate
converterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

510
480
IDFT
1

OutputParallel/
SerialBuffern=0

OAM
DAC and Analogue
processing

EOC/
AOC ibTTR
V-C

Reference Points

A
Mux
Data FrameB
FEC Output
Data FrameZi
C
i=1 to 255
Constellation
Encoder Input
Data Frame

U-C

T1532770-99

NOTE – The TTR may be generated in ATU-C without being provided from the TCM-ISDN clock.

Figure C.2/G.992.1 – ATU-C transmitter reference model for ATM transport

C.3.2

ATU-R transmitter reference model (replaces figures in 5.2)

See Figure C.3 and Figure C.4.

- 405 -

"Bits" &"Gains""Bits"LS0

2*NSCus-1
scrambler
&
FEC

crcf
LS0
LS1

Mux/
Sync
ControlLS2scrambler
&
FEC

crci

Rate
converterInterleaver

Toneordering

Rate
converter

Constellation
encoderandgainscaling

2*NSCus-2
59

OutputParallel/
SerialBufferIDFT
1
n=0

DAC and Analogue
processing

EOC/
AOC
T-R
Reference Points

A
Mux
Data Frame

Zi
i=1 to NSCus-1
C
Constellation
Encoder Input
Data FrameTTRR

B
FEC Output
Data Frame

U-R

T1532780-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (276 kHz).

Figure C.3/G.992.1 – ATU-R transmitter reference model for STM transport
Annex C-EU does not currently support STM transport. It only supports ATM transport.
"Bits"

2*NSCus-1

LS0
Cell TC

ATM0

LS1Cell TC

ATM1"Bits" &"Gains"

crcf
Mux/
Sync
Control
crci

Reference Points

scrambler&
FEC

2*NSCus-2

RateconverterToneordering
Interleaver

Rate
converter

Constellation
encoderandgainscaling

59
IDFT
1

OutputParallel/
SerialBuffern=0

DAC and Analogue
processing

EOC/
AOC
T-R

scrambler
&
FEC

A
Mux
Data FrameTTRR
B
FEC Output
Data FrameZi
C
i=1 to NSCus-1
Constellation
Encoder Input
Data Frame

U-R

T1532790-99

NOTE – The TTRR shall be generated in ATU-R from the received TTRC signal, and it is locked to 690 periods of upstream
sampling clock (276 kHz).

- 406 -

Figure C.4/G.992.1 – ATU-R transmitter reference model for ATM transport

C.3.3

ATU-C/R transmitter timing model (replacement for 5.3)

C.3.3.1

TCM-ISDN crosstalk timing model (new)Figure C.5 shows the timing chart of the crosstalk from TCM-ISDN.

TTR
377 UI
receive ISDN

transmit ISDNCO

0 ≤ propagation delay ≤ 16 UI
RT

6-7.5 UI

377 UI

receive ISDN

transmit ISDN

FEXTR

NEXTR

SC
TTRC

ATU-C TX

Frame Frame0 ≤ propagation delay ≤ 18.5 UI

Received
TTRC

SR

TTRR
NEXTC
ATU-R TXFEXTC

Frame Frame
T1532800-99

1 UI = 3.125 µs
FEXTR and NEXTR are estimated by ATU-CFEXTC and NEXTC are estimated by ATU-R

TTR

TCM-ISDN timing reference

TTRC

Timing reference used in ATU-C

Received TTR C Received TTRC at ATU-R
TTRRTiming reference used in ATU-R

SC

55 × 0.9058 µs: Offset from TTR to TTRC

SR

–42 × 0.9058 µs: Offset from received TTRC to TTRR

Figure C.5/G.992.1 – Timing chart of the TCM-ISDN crosstalk

The data stream of TCM-ISDN is transmitted in TTR period. CO transmits the stream in the first half of the TTR period- 407 -

and RT transmits in the second half of the TTR period. ATU-C receives NEXT noise from the ISDN in the first half of
the TTR period and FEXT noise from the ISDN in the second half of the TCM-ISDN period. On the other hand,
ATU-R receives FEXT noise from the ISDN in the first half of the TTR period and NEXT noise from the ISDN in thesecond half of the TTR period.
As defined in C.7.6.2 and C.7.8.3, the ATU-C shall estimate the FEXTR and NEXTR duration at ATU-R, and the
ATU-R shall estimate FEXTC and NEXTC duration at ATU-C taking propagation delay on the subscribe line into
consideration.
The ATU-C shall transmit any symbols by synchronizing with the TTRC. The ATU-R shall transmit any symbols
synchronizing with the TTRR generated from received TTRC.
C.3.3.2

Sliding window (new)Figure C.6 shows the timing chart of the transmission for the Annex C-EU downstream at ATU-C.
Hyperframe = 345 symbols

TTRC
Crosstalk
period

FEXTR

FEXTR

FEXTR

FEXTR
NEXTR

NEXTR

ATU-C
T Frame
SWB
T1532810-99

FEXTR symbol
NEXTR symbol

Sliding Window

Figure C.6/G.992.1 – Sliding window for downstream symbols

The Sliding Window defines the transmission symbols under the crosstalk noise environment synchronized to theperiod of TTR. The FEXTC/R symbol represents the symbol completely inside the FEXTC/R duration. The NEXTC/R
symbol represents any symbol containing the NEXTC/R duration. Thus, there are more NEXTC/R symbols than
FEXTC/R symbols.
The ATU-C decides which transmission symbol is FEXTR or NEXTR symbol according to the sliding window andtransmits it with the corresponding bit table. Similarly, the ATU-R decides the transmission symbol is a FEXTC or
NEXTC and transmits it with the corresponding bit table. Although the phase of the sliding window is asynchronouswith TTRC/R, the pattern is fixed to the 345 frames of the hyperframe.
C.3.3.3

ATU-C Symbol Synchronization to TTR (new)345 symbols are 34 cycles with cyclic prefix of TTRC (or 32 cycles of TTRC without cyclic prefix). This implies a PLL
lock at the ATU-R.
C.3.3.4

Dual Bitmap switching (new)The ATU-C transmits FEXTR symbols using Bitmap-FR (in FEXTR duration), and transmits NEXTR symbols using
Bitmap-NR (in NEXTR duration) according to the result of initialization. The ATU-R transmits FEXTC symbols using- 408 -

Bitmap-FC (in FEXTC duration), and transmits NEXTC symbols using Bitmap-NC (in NEXTC duration) in the samemanner.
The ATU-C shall have the capability to disable Bitmap-NC and Bitmap-NR (see C.4.5 and C.5.3). As an option, an
ATU-C may have the ability to enable or disable Bitmap-NC independently of Bitmap-NR . This is controlled by wayof the profiles negotiated through G.994.1.
C.3.3.5

Loop timing at ATU-R (new)The phase relation between received symbol and transmitted symbol of ATU-R at the reference point U-R shall meetthe phase tolerances as shown in Figure C.7.
(point U-R)
ATU-R receive
DMT symbol

ATU-R transmit
DMT symbol
T1532820-99±4.5 µs + SR

Figure C.7/G.992.1 – Loop timing for ATU-R

C.3.4

Operating modes (new)The following profiles are defined to support independent control of FEXT and NEXT bitmaps in the upstream anddownstream direction, as well as independent control of the downstream spectrum for each downstream bitmap:
Profile 1
For Profile 1, upstream transmission only uses Bitmap-FC, and downstream transmission only uses Bitmap-FR with
non-overlapped spectrum.
Profile 2
For Profile 2, upstream transmission uses both Bitmap-FC and Bitmap-NC, and downstream transmission uses both
Bitmap-FR and Bitmap-NR. Non-overlapped spectrum is used with both downstream bitmaps.
Profile 3
For Profile 3, upstream transmission only uses Bitmap-FC, and downstream transmission only uses Bitmap-FR withoverlapped spectrum. An example of a downstream PSD mask for this operating mode is shown in Figure V.3 anddescribed in Table V.3 in Appendix V.
Profile 4
For Profile 4, upstream transmission uses both Bitmap-FC and Bitmap-NC, and downstream transmission uses both
Bitmap-FR and Bitmap-NR. Overlapped spectrum is used with both downstream bitmaps.
Profile 5
For Profile 5, upstream transmission only uses Bitmap-FC, and downstream transmission uses both Bitmap-FR andBitmap-NR. Non-overlapped spectrum is used with Bitmap-NR, and overlapped spectrum is used with Bitmap-FR. An- 409 -

example of a downstream PSD mask for use with Bitmap-NR is shown in Figure V.1 and described in Table V.1 inAppendix V. An example of a downstream PSD mask for use with Bitmap-FR is shown in Figure V.2 and described inTable V.2 in Appendix V.
Profile 6
For Profile 6, upstream transmission uses both Bitmap-FC and Bitmap-NC, and downstream transmission uses both
Bitmap-FR and Bitmap-NR. Non-overlapped spectrum is used with Bitmap-NR, and overlapped spectrum is used with
Bitmap-FR. An example of a downstream PSD mask for use with Bitmap-NR is shown in Figure V.1 and described inTable V.1 in Appendix V. An example of a downstream PSD mask for use with Bitmap-FR is shown in Figure V.2 anddescribed in Table V.2 in Appendix V.
Table 11.5.1/G.994.1 contains the code points to support these profiles.
C.4

ATU-C functional characteristics (pertains to clause 7)

C.4.1

STM transmission protocols specific functionality (pertains to 7.1)

C.4.1.1

ATU-C input and output V interface for STM transport (replaces figure in 7.1.1)

See Figure C.8.

AS0 (n0 × 32 kbit/s)
AS1 (n1 × 32 kbit/s)
AS2 (n2 × 32 kbit/s)
AS3 (n3 × 32 kbit/s)
Digital
Network

twisted pair

LS0 ("C"; 16 or m0 × 32 kbit/s)

ATU-C

LS1 (m1 × 32 kbit/s)
LS2 (m2 × 32 kbit/s)
NTR
TTR
Operations, maintenance and control

T1532830-99

V-C
NOTE 1 – Optional bearer channels (both duplex and simplex) and features are shown with dotted lines.
NOTE 2 – TTR may be generated in the ATU-C without being provided from the V-C reference point.

Figure C.8/G.992.1 – ATU-C functional interfaces for STM transport
at the V-C reference point- 410 -

C.4.1.2

Payload transfer delay (supplements 7.1.4)

Since Annex C-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.1.4.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
C.4.2

ATM transmission protocols specific functionalities (pertains to 7.2)

C.4.2.1

ATU-C Input and Output V interface for ATM transport (replaces figure in 7.2.1)

See Figure C.9.

ATM layer

ATM0
Tx_ATM0P
O
RT0

Tx_Cell_Handshake0
Rx_ATM0
Rx_Cell_Handshake0

ATM1
P
O
R
T
1

Twisted pair

Tx_ATM1
ATU-C
Tx_Cell_Handshake1
Rx_ATM1
Rx_Cell_Handshake1
NTR

and interface to
Digital network

TTR
Operations, administration,
maintenance and control
V-C

T1532840-99

NOTE – TTR can be generated in the ATU-C without being provided from the V-C reference point.

Figure C.9/G.992.1 – ATU-C functional interfaces to the ATM layer at the V-C reference point

C.4.2.2

Payload transfer delay (supplements 7.2.2)

Since Annex C-EU uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.2.2.
The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms forinterleaved data.
C.4.3
C.4.3.1

Framing (pertains to 7.4)
Superframe structure (supplements 7.4.1.1)

Since the rate converter reorders the user data and overhead bit-level data to create hyperframes, the input data frames
to the constellation encoder are different than those defined in 7.4.1.1.

- 411 -

C.4.3.2

Hyperframe structure (replaces 7.4.1.3)

Annex C-EU uses the hyperframe structure shown in Figure C.10. Figure C.10 shows the phase relationship between
the TTRC and the hyperframe at the point U-C. Each hyperframe is composed of 5 superframes, which are numberedfrom 0 to 4. In order to indicate the boundary of the hyperframe, the inverse synch symbol is used for the 4thsuperframe (SPF#3), which is generated from a tone-by-tone 180-degree phase reversal of the synchronization symbol(see C.4.7.1) except for the pilot tone.
The bit-level data stream from the rate-converter is extracted according to the size of Bitmap-FR and Bitmap-NR using
the Sliding Window (see C.3.3.2).
In order to make the bit rate to be a multiple of 32 kbit/s, the dummy bits are inserted at the end of hyperframe by therate converter (see C.4.4.2). The hyperframe is composed of 345 DMT symbols, numbered from 0 to 344. Each symbol
is assigned as FEXTR or NEXTR symbol in a FEXTR or NEXTR duration (see C.2), and the following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-C transmitter (see Figure C.11).
For Ndmt = 0, 1, ..., 344

S = 272 x Ndmt mod 2760

if { (S + 271 < a) or (S > a + b) } then FEXTR symbol
elsethen NEXTR symbol
where a = 1243, b = 1461
Thus, 128 DMT symbols are allocated in the FEXTR duration, and 217 DMT symbols are allocated in the NEXTR
duration. The symbols are composed of:
FEXTR symbol:
Number of symbol using Bitmap-FR
Number of synch symbol
Number of inverse synch symbol
NEXTR symbol:

= 126
=1
=1

Number of symbol using Bitmap-NR= 214

Number of synch symbol=3

For modems not using any of the profiles defined in §C.3.4, and modems using Profile 1, during FEXT Bitmap mode,
the ATU-C shall transmit only the pilot tone in NEXTR symbols. For Profile 3, the ATU-C shall not transmit any signal
in NEXTR symbols. The remaining Profiles, i.e. Profiles 2, 4, 5, and 6 use the dual bit map technique.

- 412 -

5 Superframe (= 340 frames)(point B)
1 Superframe = 68 frames (17 ms)

1 frame = 250 µs
Rate-Converter(point U-C, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#27

TC#33

TTR
ATU-R
Crosstalk

FEXT

NEXT

FEXT

Hyperframe = 345 symbols (85 ms)
SPF#1

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol F F F F N N N N N N F F

SSliding window

SPF#2
S

S

SPF#3
N F I

Inverse synch symbol

S

NEXTR Synch symbol

F

Symbol using Bitmap-FR (FEXTR duration bitmap)

N

Symbol using Bitmap-NR (NEXTR duration bitmap)

S

FEXTR Synch symbol

Figure C.10/G.992.1 – Hyperframe structure for downstream- 413 -SPF#4
F F

FEXTR duration

1 symbol = 246 µs (544 samples)
I

NEXT

N
T1532850-99

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

0
10
20
30

1

2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
21
22
23
24
25
26
27
28
29
40
31
32
33
34
35
36
37
38
39
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
SS
61
62
63
64
65
66
67
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100 101
103
104
105
106
107
108
109
110 111101 102
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
SS
132
133
134
135
136
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162 163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181 182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
SS
203
204
205
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233 234
235
236
237
238
239
240
241
242 243
253
244
245
246
247
248
249
250
251
252
263
254
255
256
257
258
259
260
260
262
264
265
266
267
268
269
270
271
272
273
274
276
277
278
279
280
281
282
283
ISS
284
285
286
287
288
289
290
291
292
293
295
296
297
298
299
300
301
302
303
294
304 305
306
307
308
309
310
311
312
313 314
315
316
317
318
319
320
321
322
323
324
334
325
326
327
328
329
330
331
332
333
SS
335
336
337
338
339
340
341
342
343
ISS

Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol
NEXTR data symbol

SS

NEXTR synch symbol
T1535330-00

Figure C.11/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Downstream

C.4.3.3

Subframe Structure (replaces 7.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table C.1. The 34 subframes forma hyperframe.

- 414 -

Table C.1/G.992.1 – Subframe (downstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

C.4.4

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Inverse Synch Symbol#344 is Synch Symbol

Dual Bitmapping and Rate Conversion (replaces 7.15)

The functions of the rate converter (see C.4.4.2), tone ordering (see C.4.6), constellation encoding, and gain scaling
shall use one of two bitmaps stored in the ATU. This method is called the dual bitmap.
C.4.4.1

Dual Bitmap (new)The Dual Bitmap method has individual bit rates under the FEXT and NEXT noise, and this needs an additional bit andgain table, {bi, gi}, and ordered bit table, b'i, for the tone ordering. The dual bitmaps are switched synchronized withthe sliding window pattern of NEXT/FEXT symbols. The number of bits and the relative gains to be used for every tone
are calculated in the bit loading algorithm during the initialization sequence, and transmitted in R-B&G.
C.4.4.2

Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FR, Bitmap-NR and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amount of fast and interleaved data in Bitmap-FR and Bitmap-NR shall be calculated with thefollowing formulae and illustrated in Figure C.12:- 415 -

If tRf ≤ nRmax:n Rf = t Rf
nRi = nR − nRf
f Rf = t Rf
f Ri = f R − f Rf
If tRf > nRmax:

nRf = nR max

nRi = 0⎧⎡ t Rf × 10 − nRf × 6 ⎤⎪ f Rf 4 = ⎢
⎥
4
⎪
⎢
⎥
f Rf = ⎨⎡ t Rf ×10 − nRf × 7 ⎤
⎪
f
=
⎢
⎥
Rf
3
⎪
3
⎢
⎥
⎩
⎧⎪ f Ri 4 = f R = f Rf 4
f Ri = ⎨⎪⎩ f Ri3 = f R − f Rf 3
Where:
tRf
tRi
fRf and nRf
fRf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FR and Bitmap-NR, respectively.
is the number of fast bits in Bitmap-FR if the subframe (see C.4.3.3) contains 3 Bitmap-FR except forsynch symbols.
fRf4
is the number of fast bits in Bitmap-FR if the subframe contains 4 Bitmap-FR except for synch
symbols.
fRi and nRi are the numbers of interleaved bits in Bitmap-FR and Bitmap-NR, respectively.
nR
is the number of total bits in Bitmap-NR, which is specified in the B&G tables.
During FEXT Bitmap mode, nRf and nRi are zero.
To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tRf ≤ nRmax:

dummy Rf = 0

dummy Ri = ( f Ri × 126 + nRi × 214) − t Ri × 340
If tRf > nRmax:()
dummy Rf 3 = ( f Rf × 3 + nRf × 7 ) − t Rf ×10

dummy Rf 4 = f Rf × 4 + nRf × 6 − t Rf ×10

dummy Ri = ( f Ri 4 × 96 + f Ri3 × 30) − t Ri × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FR constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:- 416 -

dummy SRf = f Rf 3 − f Rf 4
The receiver shall determine Bitmap-FR and Bitmap-NR so that dummyRi is less than 126, dummyRf4 is less than 4 anddummyRf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.
#335#336#337#338#339#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22 #23 #24 #25 #26 #27 #28 #29

tRi

Interleaved DatatRj

Fast Data

NOTE – Bit Ordering:
The earlier bit is located at the bottom
each symbol in this figure.
Rate Converter

Order

When tRf ≤ nRmax

fRi =fR – fRf

fR#4 #5 #6 #7 #8 #9

dummyRi#21 #22 #23#10 #11 #12 #13#0 #1 #2 #3#14 #15 #16 #17 #18 #19 #20#343#339#340#341#342#24 #25 #26 #27 #28 #29

nRinnRf=tRf R

fRf – tRf
FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols
Symbols
Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe

When tRf > nRmax#0 #1 #2 #3#21 #22 #23#10 #11 #12 #13

dummyRi

fRi3

fRi4
dummyRf4

fR#335#336#337#338

dummyRf4

dummyRf3

dummy Rf4

fRf3
fRf4

#4 #5 #6 #7 #8 #9#14#15 #16 #17#18 #19 #20#26 #27 #28 #29#339#340#341#342#343

nRf = n
FEXTNEXT
Symbols Symbols
Subframe

FEXT
Symbols

NEXT
Symbols

Subframe

FEXT
NEXT
Symbols Symbols
Subframe

NEXT
Symbols
Subframe
T1532860-99

Figure C.12/G.992.1 – Bit distribution for Rate Converter under Dual latency and Dual Bitmap mode

C.4.5

FEXT Bitmapping (replaces 7.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (C.4.4) to transmit data only during FEXT. As an
option, modems may have the ability to enable or disable Bitmap-NR independently of Bitmap-NC in order to control
the FEXT Bitmapping mode upstream and downstream independently. For modems not using any of the profiles
defined in §C.3.4 and modems using Profile 1, the ATU-C shall transmit only the pilot tone during the NEXTR symbol.

- 417 -

For Profile 3, the ATU-C shall not transmit any signal in NEXTR symbols. The ATU-R disables Bitmap-NC and shallnot transmit any signal during the NEXTC symbol (see Figures C.10 and C.13).
For modems not using any of the profiles defined in §C.3.4, the Dual versus FEXT bitmapping mode is selected duringG.994.1 using bit "DBM" (see 10.2 and 10.3). For modems using any of the profiles defined in §C.3.4, the bitmapping
mode is selected during G.994.1.
C.4.6

Tone Ordering (replacement for 7.7)

A DMT time-domain signal has a high peak-to-average ratio (its amplitude distribution is almost Gaussian), and large
values may be clipped by the digital-to-analogue converter. The error signal caused by clipping can be considered as anadditive negative impulse for the time sample that was clipped. The clipping error power is almost equally distributed
across all tones in the symbol in which clipping occurs. Clipping is therefore most likely to cause errors on those tones
that, in anticipation of a higher received SNR, have been assigned the largest number of bits (and therefore have thedensest constellations). These occasional errors can be reliably corrected by the FEC coding if the tones with the largest
number of bits have been assigned to the interleave buffer.
The numbers of bits and the relative gains in two bitmaps to be used for every tone are calculated in ATU-R receiver,and sent back to ATU-C according to a defined protocol (see 10.9.14). The pairs of numbers are typically stored, in
ascending order of frequency or tone numbers i, in bit and gain tables for Bitmap-FR and Bitmap-NR.
For Bitmap-FR, the "tone-ordered" encoding shall first assign fRf bits from the rate converter (see C.4.4.2) to the tones
with the smallest number of bits assigned to them, and the remaining fRi bits to the remaining tones. For Bitmap-NR, it
shall first assign nRf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nRi bits to the remaining tones.
All tones shall be encoded with the number of bits assigned to them; one tone in each bitmap may therefore have a
mixture of bits from the fast and interleaved buffers.
The ordered bit tables b'iF and b'iN shall be based on the original bit tables biF and biN as follows:
For k = 0 to Ndownmax {From the bit table, find the set of all i with the number of bits per tone bi = k
Assign bi to the ordered bit allocation table in ascending order of i}
Two ordered bit tables for Bitmap-FR and Bitmap-NR shall be prepared. A complementary de-ordering procedure
should be performed in ATU-R receiver. It is not necessary, however, to send the results of the ordering process to thereceiver because the bit tables FR and NR were originally generated in ATU-R, and therefore those tables have all theinformation necessary to perform the de-ordering.
C.4.7
C.4.7.1

Modulation (pertains to 7.11)
Inverse Synchronization Symbol (replaces 7.11.4)

Except for the pilot tone, Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phasereversal of Synchronization symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
C.4.7.2

Synchronization symbol (supplements 7.11.3)

Bits d2i+1 and d2i+2, which modulate the pilot carrier that has tone index i, shall be overwritten by {0,0}, generating
the (+,+) constellation point.

- 418 -

C.4.8ATU-C Downstream transmit spectral mask (replaces 7.14)

The downstream spectral masks of Annex C-EU are as specified in this section. When C-MSG1 bit 16 is 0, the PSD
mask as specified in § C.4.8.1 shall be used. When C-MSG1 bit 16 is 1, the PSD mask as specified in § C.4.8.2 shall be
used.
C.4.8.1 Downstream non-overlapped PSD mask definition
The non-overlapped PSD masks are defined with absolute peak values in Figure C.xx. The low frequency stop band isdefined for frequencies below f1 kHz (tone n1); the high frequency stop band is defined at frequencies greater than1104 kHz (tone 256). The in-band region of these PSD masks is the frequency band from f1 kHz to 1104 kHz.

}Frequency band f (kHz)0<f<4
4 < f < f3
f3 < f < f1
f1 < f < 1104
1104 < f < 3093
3093 < f < 4545

Equation for line (dBm/Hz)
-97.5
-92.5
-92.5 + 36*log2(f/f3)-36.5-36.5 - 36.0*log2(f/1104)-90 peak, with max power in the [f,f+1MHz] window of (-36.536*log2(f/1104)+60) dBm-90 peak, with max power in the [f,f+1MHz] window of –50 dBm

4545 < f < 11040

Frequency (kHz)04
4

PSD level (dBm/Hz)
-97.5
-97.5
-92.5

Measurement BW
100 Hz100 Hz100 Hz

f3
f1
f1
1104
3093
11040
4545
11040

-92.5
-44.2
-36.5
-36.5
-90
-90
-100
-100

10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
10 kHz
1 MHz
1 MHz

The corner frequencies f1 and f3 depend on the associated upstream PSD mask used, see §I.5.6) and are defined asfollows:- 419 -

Mask designator(DS-mm)
DS-32
DS-36
DS-40
DS-44
DS-48
DS-52
DS-56
DS-60
DS-64
NOTE 1 –NOTE 2 –NOTE 3 –NOTE 4 –NOTE 5 –NOTE 6 –Associatedupstream mask
EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

f1 (kHz)f3 (kHz)138
155.25172.5
189.75207
224.25241.5
258.75
276

54.45
61.26
68.06
74.87
81.67
88.48
95.29
102.09108.9

All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The
breakpoints in the tables shall be connected by linear straight lines on a dB/log(f) plot.
MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint withfrequency fi is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next
specified breakpoint.
The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued
the 21 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that
this might impact V.90 performance, and so the floor was extended to 4 kHz.
All PSD and power measurements shall be made at the U-C interface.
Figure C.xx: Non-overlapped Downstream Channel PSD Masks.

For modems not using any of the profiles defined in §C.3.4, when C-MSG1 bit 16 is 0, the PSD mask specified in A.1.3
shall be used. When C-MSG1 bit 16 is 1, the PSD mask specified in A.1.2 shall be used.
For modems complying with Profiles 1 & 2, C-MSG1 bit 16 shall be set to 0. For modems complying with Profiles 3 to
6, C-MSG1 bit 16 shall be set to 1.
The ATU-C may use different PSD masks during FEXTR symbols and NEXTR symbols. These masks may differ from,but shall fall within, the masks defined in Annex A. Example PSD masks can be found in Appendix V.
C.4.8.2 Downstream overlapped PSD mask definition
The overlapped PSD mask is as defined in G.992.1 A.1.2. The low frequency stop band is defined for frequencies
below 25.875 kHz (tone 6); the high frequency stop band is defined at frequencies greater than 1104 kHz (tone 256).
The in-band region of this PSD mask is the frequency band from 25.875 kHz to 1104 kHz.
C.4.8.3 Downstream PSD mask definition for Profile 3
Besides the PSD defined in G.992.1 Annex C Amendment 1 Appendix V, two new PSD masks are defined for Profile 3
mode of operation: LD-TIF1 and LD-TIF2. The mask is selected in the code points in handshake.
C.4.8.3.1 LD-TIF1
LD-TIF1 is defined in Figure C. TIF1.

Figure C.TIF1 The PSD mask for LD-TIF1- 420 -

0.0497
dB/kHzPSD indBm/Hz

-30.5
peak

-36.5
peak

-23.277dB/octave

20.7909
dB/octave-65 peak-72 dB/octave-97.5 peak
+15 dBr n
0 – 4 kHz04-90 peak-50 dBm power in any
1MHz sliding window
above 4545kHz

-92.5
peak
25.875138362.25258.75Frequency f (KHz)
0<f ≤ 44<f ≤ 25.875
25.875<f ≤ 138
138 < f ≤ 258.75
258.75< f ≤ 362.25
362.25< f ≤ 1012
1012< f ≤ 1800
1800 < f ≤ 2290
2290 < f ≤ 3093
3093 < f ≤ 4545

1800
1012

3093
2290

11040

Frequency
In kHz4545

PSD (dBm/Hz) Peak values-97.5, with max power in the in 0-4 kHz band of +15 dBrn
-92.5+20.7909*log2(f/4)-36.5-43.3571+0.0497*f-30.5-30.5-23.277*log2(f/362.25)-65-65 - 72 × log2 (f/1800)–90–90 peak, with max power in the [f, f + 1 MHz] window of(–36.5 – 36 × log2 (f/1104) + 60) dBm–90 peak, with max power in the [f, f + 1 MHz] window of –50 dBm

4545 < f ≤ 11 040

C.4.8.3.2 LD-TIF2
LD-TIF2 is defined in Figure C.TIF2.
Figure C.TIF2 The PSD mask for LD-TIF2
0.6184dB/kHzPSD indBm/Hz

-36.5
peak

-28.5
peak

-17.4382
dB/octave

20.7909
dB/octave-65 peak-72 dB/octave-97.5 peak
+15 dBr n
0 – 4 kHz04-90 peak-50 dBm power in any
1MHz sliding window
above 4545kHz

-92.5
peak
25.875138

237.1875

150.9375

1800
1012

- 421 -

3093
2290

4545

11040

Frequency
In kHzFrequency f (KHz)
0<f ≤ 44<f ≤ 25.875
25.875<f ≤ 138
138 < f ≤ 150.9375
150.9375< f ≤ 237.1875
237.1875< f ≤ 1012
1012< f ≤ 1800
1800 < f ≤ 2290
2290 < f ≤ 3093
3093 < f ≤ 4545
4545 < f ≤ 11 040

PSD (dBm/Hz) Peak values-97.5, with max power in the in 0-4 kHz band of +15 dBrn
-92.5+20.7909*log2(f/4)-36.5-121.8333+0.6184*f-28.5-28.5-17.4382*log2(f/237.1875)-65-65 - 72 × log2 (f/1800)–90–90 peak, with max power in the [f, f + 1 MHz] window of(–36.5 – 36 × log2 (f/1104) + 60) dBm–90 peak, with max power in the [f, f + 1 MHz] window of –50 dBm

C.5

ATU-R Functional Characteristics (pertains to clause 8)

C.5.1

Framing (pertains to 8.4)

C.5.1.1

Superframe structure (replaces 8.4.1.1)

The superframe structure of ATU-R transmitter is identical to that of ATU-C transmitter, as specified in C.4.3.1.
C.5.1.2

Hyperframe structure (replaces 8.4.1.3)

The hyperframe structure of ATU-R transmitter is functionally similar to that of ATU-C transmitter, except that theinverse synch symbol is used in the 1st superframe (SPF#0) (see Figure C.13). The hyperframe is composed of 345
DMT symbols, numbered from 0 to 344. Each symbol is under FEXTC or NEXTC duration (see C.5.3), and thefollowing numerical formula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-R
transmitter (see Figure C.14).
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbol
then NEXTC symbol

128 DMT symbols are allocated in the FEXTC duration, and 217 DMT symbols are allocated in the NEXTC duration.
The symbols are composed of:
FEXTC symbol:
Number of symbol using Bitmap-FC
Number of synch symbol
Number of inverse synch symbol
NEXTC symbol:
Number of symbol using Bitmap-NC
Number of synch symbol

= 126
=1
=1
= 214
=3

During FEXT Bitmapping mode, the ATU-R shall not transmit any signal.

- 422 -

5 Superframe (= 340 frames)(point B)

1 Superframe = 68 frames (17 ms)

1 frame = 250 µs

Rate-Converter(point U-R, including synch symbol)
TTR Clock(TC)#0 = 2.5 ms

TC#6

TC#33

TTRR
ATU-R
Crosstalk

NEXT

NEXT

FEXT
Hyperframe = 345 symbols (85 ms)

FEXT

Superframe (SPF#0) = 69 symbols (17 ms)
ATU-C transmit
DMT symbol N N N N N F F F F N N N

SPF#2

SPF#1
N F F I F N

S

S

SPF#3

SPF#4
S

S
T1532870-99

Sliding window

FEXTC duration

1 symbol = 246 µs (68 samples)
I

Inverse synch symbol

S

NEXTC Synch symbol

F

Symbol using Bitmap-FC (FEXTC duration bitmap)

N

Symbol using Bitmap-NC (NEXTC duration bitmap)

S

FEXTC Synch symbol

Figure C.13/G.992.1 – Hyperframe structure for upstream- 423 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

ISS

69

70

7

71

72

73

74

75

76

77

78

79

80

8

81

82

83

84

85

86

87

88

89

90

9

91

92

93

94

95

96

97

98

99

100

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

118

119

120

121

101

12

122

123

124

125

126

127

128

129

130

131

13

132

133

134

135

136

SS

138

139

140

141

14

142

143

144

145

146

147

148

149

150

151

15

152

153

154

155

156

157

158

159

160

161

16

162

163

164

165

166

167

168

169

170

171

17

173

174

175

176

177

178

179

180

181

172
182

18

183

184

185

186

187

188

189

190

191

192

19

193

194

195

196

197

198

199

200

201

202

20

203

204

205

SS

207

208

209

210

211

212

21

213

214

215

216

217

218

219

220

221

222

22

223

224

225

226

227

228

229

230

231

232

23

233

234

235

236

237

238

239

240

241

242

244

245

246

247

248

249

250

251

252

253

24

243

25

254

255

256

257

258

259

260

260

262

263

26

264

265

266

267

268

269

270

271

272

273

27

274

SS

276

277

278

279

280

281

282

283

28

284

285

286

287

288

289

290

291

292

293

29

294

295

296

297

298

299

300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

SS

ISS Inverse synch symbolSS

FEXTR data symbol

FEXTR Synch symbol SS NEXTR synch symbol
NEXTR data symbol

T1535340-00

Figure C.14/G.992.1 – Symbol pattern in a hyperframe with cyclic prefix – Upstream

C.5.1.3

Subframe structure (replaces 8.4.1.4)

A subframe is 10 consecutive DMT symbols (except for synch symbols) as shown in Table C.2. The 34 subframes forma hyperframe.

- 424 -

Table C.2/G.992.1 – Subframe (upstream)
Subframe No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

C.5.2

DMT symbol No.
0-9
10-19
20-29
30-39
40-49
50-59
60-70
71-80
81-90
91-100101-110111-120121-130131-141
142-151
152-161
162-171
172-181182-191
192-201202-212213-222223-232
233-242243-252
253-262263-272273-283284-293294-303304-313314-323324-333
334-344Note#68 is Inverse Synch Symbol#137 is Synch Symbol#206 is Synch Symbol#275 is Synch Symbol#344 is Synch Symbol

Dual Bitmapping and rate conversion (replaces 8.15)

The function of the rate converter (see C.5.2.2), tone ordering (see C.5.4), constellation encoding, and gain scaling shalluse one of two bitmaps stored in the ATU. This method is called the dual bitmap.
C.5.2.1

Dual Bitmap (new)The Dual Bitmap switching shall be the same as for the downstream data, specified in C.4.4.1. The number of bits andthe relative gains to be used for every tone are calculated in the bit loading algorithm during the initialization sequence,and transmitted in C-B&G.
C.5.2.2

Rate Converter (new)The rate converter buffering changes the data frame boundaries between the reference points B and C according toBitmap-FC, Bitmap-NC and the Sliding Window. Two independent rate converters are prepared for fast data andinterleaved data. The amounts of fast and interleaved data in Bitmap-FC and Bitmap-NC shall be calculated in thefollowing formulae:
If tCf ≤ nCmax:- 425 -

nCf = tCf
nCi = nC − nCf
f Cf = tCf
f Ci = f C − f Cf
If tCf > nCmax:

nCf = nC max

nCi = 0⎧⎡ tCf × 10 − nCf × 6 ⎤⎪ f Cf 4 = ⎢
⎥
4
⎪
⎢
⎥
f Cf = ⎨⎡ tCf ×10 − nCf × 7 ⎤⎪⎥⎪ f Cf 3 = ⎢3⎢⎥⎩⎧ f Ci 4 = f C − f C 4
f Ci = ⎨⎩ f Ci 3 = f C − f Cf 3
Where:
tCf
tCi
fCf and nCf
fCf3

is the number of allocated bits in one frame for fast bytes at the reference point B.
is the number of allocated bits for interleaved bytes at the reference point B.
are the numbers of fast bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of fast bits in Bitmap-FC if the subframe (see C.5.1.3) contains 3 Bitmap-FC except forsynch symbols.
fCf4
is the number of fast bits in Bitmap-FC if the subframe contains 4 Bitmap-FC except for synch
symbols.
fCi and nCi are the numbers of interleaved bits in Bitmap-FC and Bitmap-NC, respectively.
is the number of total bits in Bitmap-NC, which is specified in the B&G tables.
nC
During FEXT Bitmap mode, nCf and nCi are zero.
To convert the bit rate to be a multiple of 32 kbit/s, the dummy bits for fast data are inserted to the tail of each subframe,
and the dummy bits for interleaved data are inserted to the end of the Hyperframe. The number of the dummy bits shallbe as follows:
If tCf ≤ nCmax:

dummyCf = 0

dummyCi = ( f Ci × 126 + nCi × 214) − tCi × 340
If tCf > nCmax:()
dummyCf 3 = ( f Cf × 3 + nCf × 7 ) − tCf ×10

dummyCf 4 = f Cf × 4 + nCf × 6 − tCf ×10

dummyCi = ( f Ci 4 × 96 + f Ci 3 × 30) − tCi × 340
If the fast data buffer uses single latency only, additional dummy bits are inserted at the tail of each FEXT symbol in the
4 Bitmap-FC constructed subframe. The number of additional dummy bits inserted at the tail of each FEXT symbol
shall be as follows:
dummySCf = fCf3 – fCf4

- 426 -

The receiver shall determine Bitmap-FC and Bitmap-NC so that dummyCi is less than 126, dummyCf4 is less than 4 anddummyCf3 is less than 3 in the initialization sequence. At the receiver, the inserted dummy bits shall be removed.
C.5.3

FEXT Bitmapping (replaces 8.16)

The FEXT Bitmapping mode uses the Dual Bitmapping technique (C.4.4) to transmit data only during FEXT. As an
option, modems may have the ability to enable or disable Bitmap-NR independently of Bitmap-NC in order to control
the FEXT Bitmapping mode upstream and downstream independently. For modems not using any of the profiles
defined in §C.3.4 and modems using Profile 1, the ATU-C shall transmit only the pilot tone during the NEXTR symbol.
For Profile 3, the ATU-C shall not transmit any signal in NEXTR symbols. The ATU-R disables Bitmap-NC and shallnot transmit any signal during the NEXTC symbol (see Figures C.10 and C.13).
For modems not using any of the profiles defined in §C.3.4, the Dual versus FEXT bitmapping mode is selected duringG.994.1 using bit "DBM" (see 10.2 and 10.3). For modems using any of the profiles defined in§C.3.4, the bitmapping
mode is selected during G.994.1.
C.5.4

Tone Ordering (pertains to 8.7)

The tone ordering algorithm shall be the same as for the downstream data, specified in C.4.4.
For Bitmap-FC, the "tone-ordered" encoding shall first assign fCf bits from the rate converter (see C.5.2.2) to the tones
with the smallest number of bits assigned to them, and the remaining fCi bits to the remaining tones. For Bitmap-NC, it
shall first assign nCf bits from the rate converter to the tones with the smallest number of bits assigned to them, and theremaining nCi bits to the remaining tones. Two ordered bit tables for Bitmap-FC and Bitmap-NC shall be prepared.
C.5.5
C.5.5.1

Modulation (pertains to 8.11)
Inverse synchronization symbol (replaces 8.11.4)

Inverse Synchronization symbol shall be generated from a tone-by-tone 180 degree phase reversal of Synchronization
symbol (i.e. + maps to –, and – maps to +, for each of the 4-QAM signal constellation).
C.5.5.2

Gain scaling in synchronization symbol (new)At initialization time, the sync symbol reference transmit PSD level shall be set at the nominal PSD level+10log(gsync2) dBm/Hz, with gsync2 defined as the average gi2 value over the used (i.e. bi > 0) subcarriers in theNEXT or FEXT bitmap, whichever results in the highest average gain. The sync symbol reference transmit PSD shallnot be updated with used subcarrier gain changes during SHOWTIME.
C.5.5.3

Nyquist frequency (supplements 8.11.1.2)

The upstream Nyquist frequency for Annex C-EU shall be at subcarrier NSCus (f = 4.3125*NSCus kHz)..

C.5.6

ATU-R Upstream Transmit Spectral Mask (replaces 8.14)

The upstream PSD masks of Annex C-EU are defined with absolute peak values in Figure C.zz. The low frequency
stop band is defined for frequencies below 25.875 kHz; the high frequency stop band is defined at frequencies greaterthan f1 kHz (tone n1). The in-band region of these PSD masks is the frequency band from 25.875 kHz to f1 kHz.
and the ATU-x may optionally support upstream masks EU-36 to EU-64 specified in Figure C.zz.
NOTE: The value of MAXNOMATPus may be limited by regional regulations.

- 427 -

PSD indBm/HzPEAKPSD(PEAKPSD+92.5)/2.69
dB/octave–72 dB/octave–100 dBm/Hz peak
–15 dB/octave–97.5
15 dBrn
0-4 kHzpeak PSD
in 1 MHz window
above 1411 kHz–92.5 peak
PSD_int dBm/Hz–110 dBm/Hz–112 dBm/Hz

0425.875

f1

Frequency band f (kHz)0<f<4
4 < f < 25.875
25.875 < f < f1
f1< f < f_int
f_int < f < 686
f > 686
Frequency (kHz)04
425.875f1
f_int
686 – 12000

f_int

686

1411
1630 5275

Equation for line (dBm/Hz)-97.5-92.5+(PEAKPSD+92.5)* log2(f/4)/log2(25.875/4)
PEAKPSDPEAKPSD-72*log2(f/f1)
PSD_int-15*log2(f/f_int)-100
PSD level (dBm/Hz)
-97.5
-97.5
-92.5
PEAKPSDPEAKPSD
PSD_int-100

Measurement BW
100 Hz100 Hz100 Hz
10 kHz
10 kHz
10 kHz
10 kHz

Additionally the PSD masks shall satisfy the following requirements:
Frequency (kHz)
1411
1630
5275
12000

Frequency
12000 in kHz

PSD level (dBm/Hz)
-100
-110
-112
-112

Measurement BW
1 MHz
1 MHz
1 MHz
1 MHz

NSCus is a function of the upstream mask parameters, which are defined as follows:- 428 -

Parameters in FEXT bitmap for mode 1, both bitmaps for mode 2 (see §C.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

32
64
64
64
64
64
64
64
64

Template
Nominal PSD
P0 (dBm/Hz)

-38.0
-38.5
-39.0
-39.4
-39.8
-40.1
-40.4
-40.7
-41.0

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.0
-35.5
-35.9
-36.3
-36.6
-36.9
-37.2
-37.5

138.00155.25172.50189.75207.00224.25241.50258.75276.00242.92274.03305.06336.33367.54399.07430.58462.04493.45

-93.2
-94.0
-94.7
-95.4
-95.9
-96.5
-97.0
-97.4
-97.9

PEAKPSD(dBm/Hz)

Frequency
f1 (kHz)

Intercept
Frequency
f_int (kHz)Intercept
PSD Level
PSD_int(dBm/Hz)

-34.5
-35.2
-36.4
-37.2
-37.9
-38.3
-38.6
-38.8
-38.8

138.00155.25172.50189.75207.00224.25241.50258.75276.00242.92273.47302.26331.87361.55392.16423.12454.51486.91

-93.2
-94.0
-94.7
-95.3
-95.8
-96.4
-96.9
-97.3
-97.8

Parameters in NEXT bitmap for mode 1 (see §C.7.3):
Designator(EU-nn)

EU-32
EU-36
EU-40
EU-44
EU-48
EU-52
EU-56
EU-60
EU-64

NSCus

Template
NominalPSD P0(dBm/Hz)

32
64
64
64
64
64
64
64
64

-38.0
-38.7
-39.9
-40.7
-41.4
-41.8
-42.1
-42.3
-42.3

Template
Maximum
Aggregate
Transmit
Power
(dBm)
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5
12.5

NOTE 1 – All PSD measurements are in 100 Ω; the POTS band total power measurement is in 600 Ω.
NOTE 2 – The breakpoint frequencies and PSD values are exact; the indicated slopes are approximate. The breakpoints
in the tables shall be connected by linear straight lines on a dB/log(f) plot.
NOTE 3 – MBW specifies the Measurement Bandwidth. The MBW specified for a certain breakpoint with frequency fi
is applicable for all frequencies satisfying fi< f ≤ fj, where fj is the frequency of the next specified breakpoint.
NOTE 4 – The power in a 1 MHz sliding window is measured in a 1 MHz bandwidth, starting at the measurement
frequency i.e. power in the [f, f + 1 MHz] window shall conform to the specification at frequency f.
NOTE 5 – The step in the PSD mask at 4 kHz is to protect V.90 performance. Originally, the PSD mask continued the21.5 dB/octave slope below 4 kHz hitting a floor of –97.5 dBm/Hz at 3400 Hz. It was recognized that this might impact
V.90 performance, and so the floor was extended to 4 kHz.
NOTE 6 – All PSD and power measurements shall be made at the U-R interface (see Figures I.3 & I.4).

Figure C.zz: Upstream Channel PSD Masks
C.5.7

Forward error correction (supplements 8.6)

The minimum FEC coding capabilities (Table 8-3) for an ATU-R shall include the following interleave depths for theinterleaved buffer:
D = 1, 2, 4, 8, and 16- 429 -C.6

EOC Operation and Maintenance (pertains to clause 9)

C.6.1

ADSL line related primitives (supplements 9.3.1)

C.6.1.1

ADSL line related near-end defects (supplements 9.3.1.3)

Two near-end defects are further defined:••

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.
Severely errored frame (SEF): A SEF defect occurs when the content of two consecutively received ADSL
synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R, does notcorrelate with the expected content over a subset of the tones. An SEF defect terminates when the content of twoconsecutively received ADSL synchronization symbols in the FEXTC duration at ATU-C, or in the FEXTR
duration at ATU-R, correlate with the expected contents over the same subset. The correlation method, theselected subset of tones, and the threshold for declaring these defect conditions are implementation discretionary.

C.6.1.2

ADSL line related far-end defects (supplements 9.3.1.4)

Loss-of-signal is further defined:•

Loss-of-signal (LOS): The ADSL power shall be measured only in the FEXTC duration at ATU-C, or only in the
FEXTR duration at ATU-R.

C.6.2

Test Parameters (supplements 9.5)

C.6.2.1

Near-end test parameters (supplements 9.5.1)

The near-end primitives are further defined:••

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio (SNR) margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.

C.6.2.2

Far-end test parameters (supplements 9.5.2)

The far-end primitives are further defined:••

Attenuation (ATN): The received signal power shall be measured only in the FEXTC duration at ATU-C, or onlyin the FEXTR duration at ATU-R.
Signal-to-Noise ratio SNR margin: During FEXT Bitmap mode, this primitive represents the snr margin in the
FEXTC duration at ATU-C, or in the FEXTR duration at ATU-R.

C.7

Initialization

C.7.1

Initialization with Hyperframe (replaces 10.1.5)

The exchange of messages between ATU-C and ATU-R shall be performed in FEXTC and FEXTR. The DMT symbol
has two symbol rates: one is 4.3125 kbaud for the symbol without a cyclic prefix, and the other is 4 x 69/68 kbaud forthe symbol with a cyclic prefix. 32 times of the TTR has the same period as 345 times of the 4.3125 kbaud, and 34
times of the TTR is the same as 345 times of 4 x 69/68 kHz.
During FEXT Bitmap mode, the ATU-R shall not transmit any signal during the NEXTC symbols duration.
For modems not using any of the profiles defined in §C.3.4 and modems using Profile 1, the ATU-C shall transmit only- 430 -

the pilot tone as the NEXTR signal except:• C-PILOT1 (C-PILOT1A) which is accompanied by a signal to allow the ATU-C to indicate the phase of
TTRC to the ATU-R (see C.7.4.1);• C-QUIETn where no signal is transmitted.
For Profile 3, the ATU-C shall not transmit any signal in NEXTR symbols.
For Profiles 2, 4, 5, and 6, the ATU-C may transmit data and pilot during the NEXTR symbols.
The ATU-C begins transmitting C-PILOT1 at the beginning of the hyperframe without cyclic prefix. The ATU-C
informs the phase of the TTRC to ATU-R during C-PILOT1. The ATU-R begins transmitting R-REVERB1 at the
beginning of the hyperframe without cyclic prefix. The ATU-R performs the training of any receiver equalizer using
this phase information of the TTRR generated from received TTRC.
From C-PILOT1 to C-SEGUE1, the following numerical formula gives the information which duration Ndmt-th DMT
symbol belongs to at ATU-R (see Figure C.15).
For Ndmt = 0, 1, …344
S = 256 x Ndmt mod 2760
if { (S + 255 < a) or (S > a + b) }else
where a = 1243, b = 1461

then FEXTR symbols
then NEXTR symbols

In order to enter C-RATES1 at the beginning of the hyperframe with cyclic prefix, the number of symbols from
C-PILOT1 to C-SEGUE1 shall be a multiple of 345 DMT symbols.
From R-REVERB1 to R-SEGUE1, the following numerical formula gives the information which duration Ndmt-th
symbol belongs to at ATU-C (see Figure C.16).
For Ndmt = 0, 1, …, 344,
S = 256 x Ndmt mod 2760
if { (S > a) and (S + 255 < a + b) }else
where a = 1315, b = 1293

then FEXTC symbols
then NEXTC symbols

From C-RATES1 to C-SEGUE3, the number of symbols is a multiple of 345 DMT symbols. The following numericalformula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-C transmits the message data in
FEXTR symbols (see Figure C.11).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760

if { (S + 271 ≥ a) and (S ≤ a + b) }else
where a = 1243, b = 1461

then NEXTR symbols
then FEXTR symbols

The ATU-R enters R-REVERB3 at the beginning of the hyperframe with cyclic prefix, which is extracted fromreceived signal. From R-REVERB3 to R-SEGUE5, the number of symbols is a multiple of 345 DMT symbols. The
following numerical formula gives the information which duration Ndmt-th DMT symbol belongs to. ATU-R transmits
the message data in FEXTC symbols (see Figure C.14).
For Ndmt = 0, 1, ..., 344
S = 272 x Ndmt mod 2760
if { (S > a) and (S + 271 < a + b) }then FEXTC symbols- 431 -

else
where a = 1315, b = 1293

then NEXTC symbols

TTRC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14

0

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
107
97
98
99
100
101
102
103
104
105
106
108
109
110
111
112
113
114
115
116
117 118
119
120
121
122
123
124
125
126
127
128
129 130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
161
151
152
153
154
155
156
157
158
159
160

162
163
164
165
166
167
168
169
170
171 172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
17
204
195
196
197
198
199
200
201
202
203
18 194
205
206
207
208
209
210
211
212
213
214 215
19
20
216
217
218
219
220
221
222
223
224
225
228
229
230
231
232
233
234
235
236
21 226 227
238
239
240
241
242
243
244
245
246
247
22 237
258
248
249
250
251
252
253
254
255
256
257
23
24
259
260
261
262
263
264
265
266
267
268 269
15
16

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311 312
313
314
315
316
317
318
319
320
321
322
29
325
326
327
328
329
330
331
332
333
30 323 324
335
336
337
338
339
340
341
342
343
344
31 334
25
26
27
28

280

FEXTR symbol

T1535350-00

NEXTR symbol

Figure C.15/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Downstream- 432 -

TTRR
0

0

1

2

3

4

5

6

7

8

9

10

1

11

12

13

14

15

16

17

18

19

20

2

22

23

24

25

26

27

28

29

30

31

3 32
4 43
5

33

34

44

54

35

45

55

6

65

7 75
8 86

76

56

66

57

77
98

99

108

109

110

23
24

82

92

102

112

62

72

63

73

83

93

103

113

64

74

84

94

104

114

53

85

95

105

115

96
107

106

116

117

118

121

122

123

124

125

126

127

128

132

133

134

135

136

137

138

139

142

143

153

163

144

154

164

145

155

165

146

156

166

147

157

167

148

158

168

149

159

169

150
161

160

170

171

172

174

175

176

177

178

179

180

181

182

184

185

186

187

188

189

190

191

192

193
204

195

205

196

206

216

21 22622 239

81

91

101

111

61

71

42

52

173

17 18318 194
19
20

80

41

51

131
152

162

15
16

60

70

90

40

50

120

141

140
151

59

79
100

39

49

69

89

97

14

58

78

9

38

48

68

88

10

13

37

47

67

87

119
11
12 129 130

36

46

21

197

207

217

198

208

218

199

209

219

200

210

220

201

211

221

202

212

222

203

213

223

215

214

224

225

227

228

229

230

231

232

233

234

235

236

238

239

240

241

242

243

244

245

246

247
258

248

249

259

250

260

251

261

252

262

253

263

254

264

255

265

256

266

257

267

268

269

270
271
272
273
274
275
276
277
278
279
281
282
283
284
285
286
287
288
289
290
26 280
292
293
294
295
296
297
298
299
300
301
27 291
28
302
303
304
305
306
307
308
309
310
311
312
25

29
30 32331 334

313

314

324
335

315

325
336

316

326
337

317

327

318

328

338

339

319

329
340

320

330
341

321

331
342

322

332
343

333
344
T1535360-00

FEXTC symbol
NEXTC symbol

Figure C.16/G.992.1 – Symbol pattern in a hyperframe without cyclic prefix – Upstream
C.7.2

Handshake – Non-standard information block (new)This section defines the format of the G.994.1 non-standard information block to support Annex C-EU, and tabulates
the parameters used by Annex C-EU. The use of these parameters is described in §C.7.3 and §C.7.4.
C.7.2.1 Non-standard information block format (new)Figure C.aa defines the format of the non-standard information block.

- 433 -

8

7

6

5

4

3

2

1

Non-standard information length = M + 6(1 octet)
T.35 country code
(2 octets – see Note 1)
Provider code (vendor identification)(4 octets – see Note 2)
Vendor-specific information(M octets – Note 3)
NOTE 1 – The value of this field shall be B5 00, the country code for USA
NOTE 2 – The value of this field shall be 43 45 4E 54, ASCII “CENT” for Centillium
Communications
NOTE 3 – These octets are defined in §C.7.2.2. Formatting of these octets shall comply with theparsing rules defined in G.994.1 §9.2.1 to §9.2.3

Figure C.aa – Non-standard information block format

C.7.2.2 Non-standard information block parameters (new)The G.994.1 non-standard parameters for Annex C-EU are listed in Tables C.a to C.b.4.2 below.
In order to minimize message length, the parameters for additional inband spectral shaping (Spar(2) octet and its related
Npar(3) octets) shall only be included in MP or MS messages, and shall not be included in CLR or CL messages. All
Annex C-EU modems shall support additional inband spectral shaping.
Note - This deviates from the rules specified in G.994.1 for standard information fields, where it isstated in §9.6:“Once a Transaction C (see 10.1) has been completed, any subsequent MS message
within the same G.994.1 session shall only contain those octets of the identification (I)and standard information (S) fields, and those blocks of non-standard information (NS)that were contained in both the CLR and CL messages of the previous Transaction C”.

Table C.a – Non-standard information field – NPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Reserved for future use

x

x

x

x

x

x

1

x

Reserved for future use

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet- 434 -

NPar(1)sTable C.b – Non-standard information field – SPar(1) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

G.992.1 Annex Q (and Annex Q-EU)

x

x

x

x

x

x

1

x

G.992.1 Annex I-EU

x

x

x

x

x

1

x

x

G.992.1 Annex C-EU

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

1

x

x

x

x

x

x

Reserved for future use

x

0

0

0

0

0

0

0

No parameters in this octet

SPar(1)sTable C.b.5 – Non-standard information field – G.992.1 Annex C-EU NPar(2) coding – Octet 1
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

nC-PILOT1 = 64

x

x

x

x

x

x

1

x

nC-PILOT1 = 128

x

x

x

x

x

1

x

x

Reserved for future use

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

nC-PILOT1 = 96

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex C-EU NPar(2)s

Table C.b.5.1 – Non-standard information field – G.992.1 Annex C-EU NPar(2) coding – Octet 2
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

R-ACK1

x

x

x

x

x

x

1

x

R-ACK2

x

x

x

x

x

1

x

x

DBM

x

x

x

x

1

x

x

x

nC-PILOT1 = 48

x

x

x

1

x

x

x

x

nC-PILOT1 = 32

x

x

1

x

x

x

x

x

G.997.1 – Clear EOC OAM

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex C-EU NPar(2)s – Octet 2

Since Annex C-EU only supports ATM transport, STM and ATM parameters are not specified.

- 435 -

Table C.b.5.2 – Non-standard information field – G.992.1 Annex C-EU NPar(2) coding – Octet 3
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

nC-PILOT1 = 16

x

x

x

x

x

x

1

x

A48 / B48

x

x

x

x

x

1

x

x

C-REVERB33-63

x

x

x

x

1

x

x

x

A24 / B24

x

x

x

1

x

x

x

x

C-REVERB6-31

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex C-EU NPar(2)s – Octet 3

Table C.b.5.3 – Non-standard information field – G.992.1 Annex C-EU NPar(2) coding – Octet 4
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Profile 1

x

x

x

x

x

x

1

x

Profile 2

x

x

x

x

x

1

x

x

Profile 3

x

x

x

x

1

x

x

x

Profile 4

x

x

x

1

x

x

x

x

Profile 5

x

x

1

x

x

x

x

x

Profile 6

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex C-EU NPar(2)s – Octet 3

Table C.b.6 – Non-standard information field – G.992.1 Annex C-EU SPar(2) coding
Bits
8

7

6

5

4

3

2

1

x

x

x

x

x

x

x

1

Reserved for future use

G.992.1 Annex C-EU SPar(2)s

x

x

x

x

x

x

1

x

Extended upstream

x

x

x

x

x

1

x

x

Profile 3 downstream PSD

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet- 436 -

Table C.b.6.2 – Non-standard information field – G.992.1 Annex C-EU Extended upstream NPar(3) coding Octet
1
Bits
8

7

6

5

4

3

2

1

G.992.1 Annex C-EU Extended upstream NPar(3)s –Octet 1

x

x

x

x

x

x

x

1

Mode 1 upstream mask

x

x

x

x

x

x

1

x

Mode 2 upstream mask

x

x

x

x

x

1

x

x

Optional upstream masks for non-overlapped spectrum

x

x

x

x

1

x

x

x

EU-64

x

x

x

1

x

x

x

x

EU-32

x

x

1

x

x

x

x

x

EU-36

x

x

0

0

0

0

0

0

No parameters in this octet

Table C.b.6.2.1 – Non-standard information field – G.992.1 Annex C-EU Extended upstream NPar(3) coding
Octet 2
Bits
8

7

6

5

4

3

2

1

x

X

x

x

x

x

x

1

EU-40

x

X

x

x

x

x

1

x

EU-44

x

X

x

x

x

1

x

x

EU-48

x

X

x

x

1

x

x

x

EU-52

x

x

x

1

x

x

x

x

EU-56

x

x

1

x

x

x

x

x

EU-60

x

x

0

0

0

0

0

0

No parameters in this octet

G.992.1 Annex C-EU Extended upstream NPar(3)sOctet 2

Table C.b.6.3 – Non-standard information field – G.992.1 Annex C-EU Profile 3 downstream PSD NPar(3)coding Octet 1
Bits

C.7.3

8

7

6

5

4

3

2

1

G.992.1 Annex C-EU Profile 3 downstream NPar(3)sOctet 1

x

x

x

x

x

x

x

1

LD-TIF1

x

x

x

x

x

x

1

x

LD-TIF2

x

x

x

x

x

1

x

x

FBMsOL

x

x

x

x

1

x

x

x

Reserved for future use

x

x

x

1

x

x

x

x

Reserved for future use

x

x

1

x

x

x

x

x

Reserved for future use

x

x

0

0

0

0

0

0

No parameters in this octet

Handshake – Parameter definitions (supplements 10.2)

C.7.3.1 Handshake – ATU-C (supplements 10.2)
From C-SILENT1, the ATU-C may transition to either C-TONES or C-INIT under instruction of the network operator.

- 437 -

- 438 -C.7.3.1.1

CL messages (supplements 10.2.1)

Table C.3/G.992.1 – ATU-C CL message bit definitions for Annex C-EUNSF parameter
DBM

Profile 1
Profile 2
Profile 3
Profile 4
Profile 5Profile 6
G.992.1 Annex C-EU

nC-PILOT1=128
nC-PILOT1=96
nC-PILOT1=64
nC-PILOT1=48
nC-PILOT1=32
nC-PILOT1=16
A48 / B48
A24 / B24
C-REVERB33-63
C-REVERB6-31
Extended upstream
Profile 3 downstream
PSD
EU-xx

Mode 1 upstream mask

Definition
If set to ZERO, this bit shall indicate Bitmap-NR and Bitmap-NC are enabled (Dual
Bitmap mode) and are used to transmit data. If set to ONE, this bit shall indicate
Bitmap-NR and Bitmap-NC are disabled (FEXT Bitmap mode), i.e. only Bitmap-FR andBitmap-FC are used to transmit data by ATU-C and ATU-R respectively. This mode
selection shall be only performed by the ATU-C. If it is set to ONE in a CL message, it
must be set to ONE in subsequent MS messages from either the ATU-C or ATU-R (onlyapplicable for G.992.1 Annex C/C-EU). (Note 1)
If set to ONE, this bit shall indicate that the ATU-C supports Profile 1
If set to ONE, this bit shall indicate that the ATU-C supports Profile 2
If set to ONE, this bit shall indicate that the ATU-C supports Profile 3
If set to ONE, this bit shall indicate that the ATU-C supports Profile 4
If set to ONE, this bit shall indicate that the ATU-C supports Profile 5
If set to ONE, this bit shall indicate that the ATU-C supports Profile 6
If set to ONE, this Spar(1) bit indicates that the ATU-C is configured to support G.992.1
Annex C-EU. An Annex C-EU ATU-C shall support negotiation of the optional pilot
tones, TTR indication signals, and profiles.

This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission ofpilot tone on subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-C supports transmission ofpilot tone on subcarrier 96.
This NPar(2) bit shall also be set to ONE, indicating that the ATU-C supports transmissionof pilot tone on subcarrier 64.
This NPar(2) bit shall also be set to ONE, indicating that the ATU-C supports transmissionof pilot tone on subcarrier 48.
This NPar(2) bit shall also be set to ONE, indicating that the ATU-C supports transmissionof pilot tone on subcarrier 32.
This NPar(2) bit shall also be set to ONE, indicating that the ATU-C supports transmissionof pilot tone on subcarrier 16.
This NPar(2) bit shall also be set to ONE, indicating that the ATU-C supports transmissionof TTR indication signal A48 / B48.
This NPar(2) bit shall also be set to ONE, indicating that the ATU-C supports transmissionof TTR indication signal A24 / B24.
This NPar(2) bit shall also be set to ONE, indicating that the ATU-C supports transmissionof TTR indication signal C-REVERB33-63.
This NPar(2) bit shall also be set to ONE, indicating that the ATU-C supports transmissionof TTR indication signal C-REVERB6-31.
If set to ONE, this Spar(2) bit indicates that the ATU-C is configured to support extended
upstream.
If set to ONE, this Spar(2) bit indicates that the ATU-C is configured to support profile 3.
If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate theextended upstream masks that the ATU-C supports. For non-overlapped spectrum,
extended upstream masks are associated with downstream masks according to Figure C.xx.
For overlapped spectrum, any EU-xx may be used with the overlapped downstream
spectrum specified in §C.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 1 (different masks during FEXT and NEXT periods).

- 439 -

Mode 2 upstream mask
Optional upstream
masks for nonoverlapped spectrum
LD-TIF1

If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support upstreammask mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support theoptional upstream masks when using non-overlapped spectrum downstream.

If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support theoptional LD-TIF1 downstream PSD of profile 3.
LD-TIF2
If set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support theoptional LD-TIF2 downstream PSD of profile 3.
FBMsOLIf set to ONE, this NPar(3) bit indicates that the ATU-C is configured to support theoptional FBMsOL downstream PSD of profile 3.
Note 1: The DBM bit is only used to maintain backward compatibility with G.992.1 (1999) Annex C. If any of the
profile bits (Table 11.5.1/G.994.1) are set to ONE in a received CLR message, DBM shall be set to ONE in the CL
message and shall be ignored by the ATU-R.
Note 2: Only one of LD-TIF1, LD-TIF2 and FBMsOL bits can be set to 1.

- 440 -

C.7.3.1.2

MS messages (supplements 10.2.2)

Table C.4/G.992.1 – ATU-C MS message bit definitions for Annex C-EUNSF parameter
DBM

Profile 1
Profile 2
Profile 3
Profile 4
Profile 5Profile 6
G.992.1 Annex C-EU

nC-PILOT1=128
nC-PILOT1=96
nC-PILOT1=64
nC-PILOT1=48
nC-PILOT1=32
nC-PILOT1=16
A48 / B48
A24 / B24
C-REVERB33-63
C-REVERB6-31
Extended upstream
Profile 3 downstream
PSD
EU-xx

Mode 1 upstream mask
Mode 2 upstream mask

Definition
If set to ZERO, this bit shall indicate Bitmap-NR and Bitmap-NC are enabled (Dual Bitmapmode) and are used to transmit data. If set to ONE, this bit shall indicate Bitmap-NR andBitmap-NC are disabled (FEXT Bitmap mode), i.e. only Bitmap-FR and Bitmap-FC areused to transmit data by ATU-C and ATU-R respectively. This mode selection shall be only
performed by ATU-C. This bit shall be set to ONE if it was set to ONE in a previous CL
message (only applicable for G.992.1 Annex C/C-EU). (Note 1)
If set to ONE, this bit shall indicate that the ATU-C is selecting Profile 1
If set to ONE, this bit shall indicate that the ATU-C is selecting Profile 2
If set to ONE, this bit shall indicate that the ATU-C is selecting Profile 3
If set to ONE, this bit shall indicate that the ATU-C is selecting Profile 4
If set to ONE, this bit shall indicate that the ATU-C is selecting Profile 5
If set to ONE, this bit shall indicate that the ATU-C is selecting Profile 6
If set to ONE, this Spar(1) bit indicates that the ATU-C is selecting G.992.1 Annex C-EU.
An Annex C-EU ATU-C shall support negotiation of the optional pilot tones, TTR
indication signals, and profiles.

If set to ONE, this NPar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 128 (Note 2).
If set to ONE, this bit NPar(2) shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 96 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 64 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 48 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 32 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-C is selecting the pilot tone on
subcarrier 16 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-C is selecting TTR indication
signal A48 / B48 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-C is selecting TTR indication
signal A24 / B24 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-C is selecting TTR indication
signal C-REVERB33-63 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-C is selecting TTR indication
signal C-REVERB6-31 (Note 2).
If set to ONE, this Spar(2) bit indicates that the ATU-C is selecting extended upstream
operation.
If set to ONE, this Spar(2) bit indicates that the ATU-C is selecting profile 3.
If set to ONE, this Npar(3) bit indicates that the ATU-C is selecting upstream PSD mask
US-xx. For non-overlapped spectrum, extended upstream masks are associated withdownstream masks according to Figure C.13. For overlapped spectrum, any EU-xx may be
used with the overlapped downstream spectrum specified in §C.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 1(different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting upstream mask mode 2(same masks during FEXT and NEXT periods). (Note 2)- 441 -

Optional upstream
masks for nonoverlapped spectrum
LD-TIF1

If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting the optional LD-TIF1
downstream PSD of profile 3.
LD-TIF2
If set to ONE, this NPar(3) bit indicates that the ATU-C is selecting the optional LD-TIF2
downstream PSD of profile 3.
FBMsOLIf set to ONE, this NPar(3) bit indicates that the ATU-C is selecting the optional FBMsOL
downstream PSD of profile 3.
Note 1: The DBM bit is only used to maintain backward compatibility with G.992.1 (1999) Annex C.
Note 2: One and only one pilot tone bit, and one and only one TTR indication signal bit shall be set in an MS message.

C.7.3.2 Handshake – ATU-R (supplements 10.3)
Upon command from the host controller, the ATU-R shall initiate handshaking by transitioning from the R-SILENT0
state to either the G.994.1 R-TONES-REQ state or the R-INIT state.

- 442 -

C.7.3.2.1

CLR messages (supplements 10.3.1)

Table C.5/G.992.1 – ATU-R CLR message bit definitions for Annex C-EUNSF parameter
DBM
Profile 1
Profile 2
Profile 3
Profile 4
Profile 5Profile 6
G.992.1 Annex CEU

Definition
This bit shall be set to ONE.
If set to ONE, this bit shall indicate that the ATU-R supports Profile 1
If set to ONE, this bit shall indicate that the ATU-R supports Profile 2
If set to ONE, this bit shall indicate that the ATU-R supports Profile 3
If set to ONE, this bit shall indicate that the ATU-R supports Profile 4
If set to ONE, this bit shall indicate that the ATU-R supports Profile 5
If set to ONE, this bit shall indicate that the ATU-R supports Profile 6
If set to ONE, this Spar(1) bit indicates that the ATU-R is configured to support G.992.1 Annex
C-EU.

nC-PILOT1=128

This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot toneon subcarrier 128.
This Npar(2) bit shall be set to ONE, indicating that the ATU-R supports reception of pilot toneon subcarrier 96.
This bit shall be set to ONE, indicating that the ATU-R supports reception of pilot tone on
subcarrier 64.
If set to ONE, this bit shall indicate that the ATU-R supports reception of pilot tone on subcarrier48.
If set to ONE, this bit shall indicate that the ATU-R supports reception of pilot tone on subcarrier32.
If set to ONE, this bit shall indicate that the ATU-R supports reception of pilot tone on subcarrier
16.
This bit shall be set to ONE, indicating that the ATU-R supports reception of either TTR
indication signal A48 or B48 (Note 1)
If set to ONE, this bit shall indicate that the ATU-R supports reception of either TTR indication
signal A24 or B24 (Note 1)
If set to ONE, this bit shall indicate that the ATU-R supports reception of TTR indication signal
C-REVERB33-63
If set to ONE, this bit shall indicate that the ATU-R supports reception of TTR indication signal
C-REVERB6-31
If set to ONE, this Spar(2) bit indicates that the ATU-R is configured to support extended
upstream.
If set to ONE, this Spar(2) bit indicates that the ATU-R is configured to support profile 3.

nC-PILOT1=96
nC-PILOT1=64
nC-PILOT1=48
nC-PILOT1=32
nC-PILOT1=16
A48 / B48
A24 / B24
C-REVERB33-63
C-REVERB6-31
Extended upstream
Profile 3
downstream PSD
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum
LD-TIF1
LD-TIF2

If the Extended upstream Spar(2) bit is set to ONE, these Npar(3) bits indicate the extended
upstream masks that the ATU-R supports. For non-overlapped spectrum, extended upstream
masks are associated with downstream masks according to Figure C.13. For overlapped
spectrum, any EU-xx may be used with the overlapped downstream spectrum specified in§C.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstream mask
mode 1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support upstream mask
mode 2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support the optional
upstream masks when using non-overlapped spectrum downstream.
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support the optional
LD-TIF1 downstream PSD of profile 3.
If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support the optional
LD-TIF2 downstream PSD of profile 3.

- 443 -

FBMsOL

If set to ONE, this NPar(3) bit indicates that the ATU-R is configured to support the optional
FBMsOL downstream PSD of profile 3.
Note 1 – A48 and A24 shall not be used for Profile 3.

C.7.3.2.2

MS messages (supplements 10.3.2)

Table C.6/G.992.1 – ATU-R MS message NPar(2) bit definitions for Annex C-EUNSF parameter
DBM

Profile 1
Profile 2
Profile 3
Profile 4
Profile 5Profile 6

Definition
If set to ZERO, this bit shall indicate Bitmap-NR and Bitmap-NC are enabled (Dual
Bitmap mode) and are used to transmit data. If set to ONE, this bit shall indicate
Bitmap-NR and Bitmap-NC are disabled (FEXT Bitmap mode), i.e. only Bitmap-FR andBitmap-FC are used to transmit data by ATU-C and ATU-R respectively. This mode
selection shall be only performed by ATU-C. This bit shall be set to ONE if it was set to
ONE in a previous CL message (only applicable for G.992.1 Annex C/C-EU). (Note 1)
If set to ONE, this bit shall indicate that the ATU-R is selecting Profile 1
If set to ONE, this bit shall indicate that the ATU-R is selecting Profile 2
If set to ONE, this bit shall indicate that the ATU-R is selecting Profile 3
If set to ONE, this bit shall indicate that the ATU-R is selecting Profile 4
If set to ONE, this bit shall indicate that the ATU-R is selecting Profile 5
If set to ONE, this bit shall indicate that the ATU-R is selecting Profile 6

G.992.1 Annex C-EU

nC-PILOT1=128
nC-PILOT1=96
nC-PILOT1=64
nC-PILOT1=48
nC-PILOT1=32
nC-PILOT1=16
A48 / B48
A24 / B24
C-REVERB33-63
C-REVERB6-31
Extended upstream
Profile 3 downstream
PSD
EU-xx

If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 128 (Note 2).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 96 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 64 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 48 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 32 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-R is selecting the pilot tone on
subcarrier 16 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-R is selecting the TTR
indication signal A48 / B48 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-R is selecting the TTR
indication signal A24 / B24 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-R is selecting the TTR
indication signal C-REVERB33-63 (Note 2).
If set to ONE, this NPar(2) bit shall indicate that the ATU-R is selecting the TTR
indication signal C-REVERB6-31 (Note 2).
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting extended upstream
operation.
If set to ONE, this Spar(2) bit indicates that the ATU-R is selecting profile 3.
If set to ONE, this Npar(3) bit indicates that the ATU-R is selecting upstream PSD mask
US-xx. For non-overlapped spectrum, extended upstream masks are associated used withdownstream masks according to Figure C.13. For overlapped spectrum, any EU-xx may be
used with the overlapped downstream spectrum specified in §I.4.8.2.

- 444 -

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum
LD-TIF1

If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode
1 (different masks during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting upstream mask mode
2 (same mask during FEXT and NEXT periods). (Note 2)
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting one of the optional
upstream masks when using non-overlapped spectrum downstream.

If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting the optional LD-TIF1
downstream PSD of profile 3.
LD-TIF2
If set to ONE, this NPar(3) bit indicates that the ATU-R is selecting the optional LD-TIF2
downstream PSD of profile 3.
FBMsOLIf set to ONE, this NPar(3) bit indicates that the ATU-R is selecting the optional FBMsOL
downstream PSD of profile 3.
Note 1: The DBM bit is only used to maintain backward compatibility with G.992.1 (1999) Annex C.
Note 2 – One and only one pilot tone bit, and one and only one TTR indication signal bit shall be set in an MS
message- 445 -

C.7.3.2.3

MP messages (new)Table C.6a/G.992.1 – ATU-R MP message bit definitions for Annex C-EUNSF parameter
R-ACK1
R-ACK2
G.992.1 Annex C-EU
DBM
Profile 1
Profile 2
Profile 3
Profile 4
Profile 5Profile 6

Definition
Proposes that the ATU-C send C-PILOT1A, C-QUIET3A, C-PILOT2 and C-QUIET5
during transceiver training.
Proposes that the ATU-C send C-PILOT1, C-PILOT2 and C-PILOT3 during transceivertraining.
If set to ONE, this Spar(1) bit indicates that the ATU-R is proposing G.992.1 Annex I-EU.
This bit shall be set to ONE if it was set to ONE in a previous CL message (Note 1)
If set to ONE, this bit shall indicate that the ATU-R is proposing to use Profile 1
If set to ONE, this bit shall indicate that the ATU-R is proposing to use Profile 2
If set to ONE, this bit shall indicate that the ATU-R is proposing to use Profile 3
If set to ONE, this bit shall indicate that the ATU-R is proposing to use Profile 4
If set to ONE, this bit shall indicate that the ATU-R is proposing to use Profile 5
If set to ONE, this bit shall indicate that the ATU-R is proposing to use Profile 6

C-PILOT

If set to ONE, this bit shall indicate that the ATU-R wishes to propose a pilot tone andTTR indication signal. This bit shall be set to ONE to propose one of the profiles definedin §C.3.4.

nC-PILOT1=128

If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the pilot tone on
subcarrier 128 (Note 2).
If set to ONE, this Npar(2) bit shall indicate that the ATU-C is proposing the pilot tone on
subcarrier 96 (Note 2).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the use of pilot
tone on subcarrier 64 (Note 2).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the use of pilot
tone on subcarrier 48 (Note 2).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the use of pilot
tone on subcarrier 32 (Note 2).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the use of pilot
tone on subcarrier 16 (Note 2).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the use of TTR
indication signal A48 / B48 (Note 2).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the use of TTR
indication signal A24 / B24 (Note 2).

nC-PILOT1=96
nC-PILOT1=64
nC-PILOT1=48
nC-PILOT1=32
nC-PILOT1=16
A48 / B48
A24 / B24
C-REVERB33-63
C-REVERB6-31
Extended upstream
Profile 3 downstream
PSD
EU-xx

Mode 1 upstream
maskMode 2 upstream
mask
Optional upstream
masks for nonoverlapped spectrum

If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the use of TTR
indication signal C-REVERB33-63 (Note 2).
If set to ONE, this Npar(2) bit shall indicate that the ATU-R is proposing the use of TTR
indication signal C-REVERB6-31 (Note 2).
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing extended upstream
operation.
If set to ONE, this Spar(2) bit indicates that the ATU-R is proposing profile 3.
If set to ONE, this Npar(3) bit indicates that the ATU-R is proposing upstream PSD mask
US-xx. For non-overlapped spectrum, extended upstream masks are associated withdownstream masks according to Figure C.13. For overlapped spectrum, any EU-xx may be
used with the overlapped downstream spectrum specified in §C.4.8.2.
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode
1 (different masks during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing upstream mask mode
2 (same mask during FEXT and NEXT periods).
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing one of the optional
upstream masks when using non-overlapped spectrum downstream.

- 446 -

LD-TIF1

If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing the optional LDTIF1 downstream PSD of profile 3.
LD-TIF2
If set to ONE, this NPar(3) bit indicates that the ATU-R is proposing the optional LDTIF2 downstream PSD of profile 3.
FBMsOLIf set to ONE, this NPar(3) bit indicates that the ATU-R is proposing the optional
FBMsOL downstream PSD of profile 3.
Note 1: The DBM bit is only used to maintain backward compatibility with G.992.1 (1999) Annex C.
Note 2: One and only one pilot tone bit, and one and only one TTR indication signal bit shall be set in an MP
message.

C.7.4

Transceiver Training – ATU-C (supplements 10.4)

During transceiver training from C-REVERB1 to C-SEGUE1 except C-PILOTn and C-QUIETn, the ATU-C shalltransmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode). For modems not using
any of the profiles defined in §C.3.4 and modems using Profile 1, the ATU-C shall not transmit the NEXTR symbols
except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). For Profile 3, the ATU-C shall not transmit any
signal in NEXTR symbols. The duration of each state is defined as Figure C.21.
C.7.4.1

C-PILOT1 (supplements 10.4.2)

The ATU-C shall start the NSWF (sliding window frame) counter from 0 immediately after entering C-PILOT1, andincrement the NSWF counter modulo 345 after transmission of each DMT symbol. According to the sliding windowfunction and this counter, the ATU-C decides to transmit all of the subsequent symbols in either FEXTR or NEXTR
symbols (for example, see Figures C.11, C.15 and C.19).
C-PILOT1 has two signals.
The first signal is the pilot tone as a single frequency sinusoid.
For Profiles 1 & 2, the frequency of the pilot tone shall be selected from one of the following choices:1.
fC-PILOT1 = 276 kHz (nC-PILOT1 = 64);
2.
fC-PILOT1 = 207 kHz (nC-PILOT1 = 48).
For Profiles 3 to 6, the frequency of the pilot tone shall be selected from one of the following choices:1.
fC-PILOT1 = 276 kHz (nC-PILOT1 = 64);
2.
fC-PILOT1 = 207 kHz (nC-PILOT1 = 48);
3.
fC-PILOT1 = 138 kHz (nC-PILOT1 = 32);
4.
fC-PILOT1 = 69 kHz (nC-PILOT1 = 16).
For modems not using any of the profiles defined in §C.3.4, the frequency of the pilot tone shall be:
fC-PILOT1 = 276 kHz (nC-PILOT1 = 64)
Editor’s note: We need to decide how much extended upstream to support for each profile and then which pilot tones
are necessary for this. For example, Profile 3 is long reach. It probably does not make sense to support all the way to
subcarrier 64 upstream, in which case, there is no need for any pilot tone above tone 64.
Transmitters that use any of the profiles defined in §C.3.4 shall support all of the pilot tones specified for the supported
profiles. For backwards compatibility, receivers shall support nC-PILOT1 = 64. Support of the other pilot tones by areceiver is optional. The pilot tone shall be selected during G.994.1.
The second signal is the TTR indication signal used to transmit NEXTR/FEXTR information. The ATU-R can detect
the phase information of the TTRC from this signal.
For Profiles 1 & 2, the TTR indication signal shall be selected from one of the following choices:
1. A48 signal –the constellation encoding of the 48th carrier with 2-bit constellation as follows:- 447 -

(+ , +) to indicate a FEXTR symbol;(+ , –) to indicate a NEXTR symbol.
2. C-REVERB33-63 – subcarriers 33 through 63 of C-REVERB, transmitted only in the first four DMT
symbols of each hyperframe in C-PILOT1 to indicate the beginning of the hyperframe.
For Profile 3, the TTR indication signal shall be selected from one of the following choices:1.
B48 signal –the constellation encoding of the 48th carrier with 2-bit constellation as follows:(+ , –) to indicate the first and the last symbol in consecutive FEXTR symbols;(+ , +) to indicate the other symbols in consecutive FEXTR symbols.
2. B24 signal – the constellation encoding of the 24th carrier with 2-bit constellation as follows:(+ , –) to indicate the first and the last symbol in consecutive FEXTR symbols;(+ , +) to indicate the other symbols in consecutive FEXTR symbols.
3. C-REVERB6-31 – subcarriers 6 through 31 of C-REVERB, transmitted only in the first four DMT symbols
of each hyperframe in C-PILOT1 to indicate the beginning of the hyperframe.
For Profiles 4 to 6, the TTR indication signal shall be selected from one of the following choices:
1. A48 signal – the constellation encoding of the 48th carrier with 2-bit constellation as follows:(+ , +) to indicate a FEXTR symbol;(+ , –) to indicate a NEXTR symbol.
2.

A24 signal – the constellation encoding of the 24th carrier with 2-bit constellation as follows:(+ , +) to indicate a FEXTR symbol;(+ , –) to indicate a NEXTR symbol.

3. C-REVERB6-31 – subcarriers 6 through 31 of C-REVERB, transmitted only in the first four DMT symbols
of each hyperframe in C-PILOT1 to indicate the beginning of the hyperframe.
For modems not using any of the profiles defined in §C.3.4, the TTR indication signal shall be:
A48 signal – the constellation encoding of the 48th carrier with 2-bit constellation as follows:(+ , +) to indicate a FEXTR symbol;(+ , –) to indicate a NEXTR symbol.
Editor’s note: We need to decide how much extended upstream to support for each profile and then which TTR
indication signals are necessary for this.
Transmitters that use any of the profiles defined in §C.3.4 shall support all of the TTR indication signals specified forthe supported profiles. For backwards compatibility, receivers shall support TTR indication signal A48. Support for theother TTR indication signals by a receiver is optional. The TTR signal shall be selected during G.994.1.
C.7.4.2

C-PILOT1A (supplements 10.4.3)

C-PILOT1A has two signals and it is the same transmitted signal as C-PILOT1 (C.7.4.1).
C.7.4.3

C-REVERB3 (supplements 10.4.11)

In order to synchronize the first symbol of C-RATES1 with the beginning of the hyperframe and to inform the enteringtiming of C-RATES1 to the ATU-R, the first symbol of C-SEGUE1 shall be transmitted inside of the FEXTR duration
as shown in Figure C.17. Therefore, the duration of C-REVERB3 is 3628 DMT symbols.
C.7.4.4

C-REVERB1 (supplements 10.4.5)

Bits d2i+1 and d2i+2, which modulate the pilot carrier that has tone index i, shall be overwritten by {0,0}, generating- 448 -

the (+,+) constellation point.

TTRC
20 symbols
C-REVERB3

C-SEGUE1

C-RATES1

the time of the detection
C-SEGUE1

R-REVERB3
T1532880-99

Figure C.17/G.992.1 – Timing diagram from C-SEGUE1 to C-RATES1

C.7.5

Transceiver Training – ATU-R (supplements 10.5)

During transceiver training from R-REVERB1 to R-SEGUE1 except R-QUIETn, the ATU-R shall transmit both
FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC
symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is defined as Figure C.21.
C.7.5.1

R-QUIET2 (supplements 10.5.1)

The ATU-R enters R-REVERB1 after it completes timing recovery and Hyperframe synchronization from
C-PILOT1/C-PILOT1A.

- 449 -

C.7.5.2

R-REVERB1 (supplements 10.5.2)

The data pattern used in R-REVERB1 is the pseudo-random upstream sequence PRU defined in 8.11.3 , repeated asnecessary for the selected NSCus:⎧⎪d n = 1⎨⎪⎩d n = d n −5

for n = 1 to 6
⊕ d n − 6 for n = 7 to 64(C.10-1)

The period of PRU is only 63 bits, so dn+63 is equal to dn.
The ATU-R shall start its NSWF counter immediately after entering R-REVERB1, and then increment the NSWF
counter with modulo 345 from 0 when it transmits each DMT symbol. The ATU-C and ATU-R shall have the samevalue since hyperframe alignment between the ATU-C and ATU-R shall be maintained. According to the sliding
window and this counter, the ATU-R decides to transmit all of the subsequent symbols in either the FEXTC or the
NEXTC symbol.
C.7.5.3

R-QUIET3 (replaces 10.5.3)

The final symbol of R-QUIET3 accommodates the frame alignment of the transmitter to that of the receiver. It may be
shortened by any number of samples. The maximum duration of R-QUIET3 is 6145 DMT symbols.
C.7.5.4

R-REVERB2 (supplements 10.5.5)

After ATU-R detects C-SEGUE1, the ATU-R enters R-SEGUE1. The maximum duration of R-REVERB2 is 3643
DMT symbols.
C.7.6

Channel analysis (ATU-C) (supplements 10.6)

The ATU-C shall transmit only FEXTR symbols from C-RATES1 to C-CRC2. For modems not using any of the
profiles defined in §C.3.4 and modems using Profiles 1, 2, 4, 5 and 6, the ATU-C shall not transmit the NEXTR
symbols except for the pilot tone. For Profile 3, the ATU-C shall not transmit any signal in NEXTR symbols. During
C-MEDLEY, the ATU-C shall transmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmapmode). For modems not using any of the profiles defined in §C.3.4 and modems using Profile 1, the ATU-C shall nottransmit NEXTR symbols except the pilot tone, when Bitmap-NR is disabled (FEXT Bitmap mode). For Profile 3, the
ATU-C shall not transmit any signal in NEXTR symbols. The duration of each state is defined in Figure C.21.
C.7.6.1

C-SEGUE1 (supplements 10.6.1)

The duration of C-SEGUE1 is 20 symbols in order that the first symbol of C-SEGUE1 shall be inside of the FEXTR
duration.
C.7.6.2

C-MEDLEY (replaces 10.6.6)

C-MEDLEY is a wideband pseudo-random signal used for estimation at the ATU-R of the downstream SNR. The data
to be transmitted are derived from the pseudo-random sequence, PRDm, defined as:
d n = 1 for n = 1 to 14 and d n = d n-5 ⊕ d n-11 ⊕ d n-12 ⊕ d n-14 for n> 14,
and modulated as defined in 10.4.5. In contrast to C-REVERB1, the cyclic prefix is used and the data sequence
continues from one symbol to the next (i.e. d1 to d14 are not re-initialized for each symbol). Because the sequence is oflength 214-1, and far fewer bits are used for each symbol, the subcarrier vector for C-MEDLEY changes from one
symbol period to the next. For non-overlapped spectrum, 2*(256-mm+1) bits are used each symbol, where mm is theminimum subcarrier specified for PSD mask DS-mm in Table C.13. For overlapped spectrum, 2*251 bits are used eachsymbol. The pilot subcarrier is overwritten by the (+,+) signal constellation. The duration of C-MEDLEY is as shown in
Figure C.26. Following C-MEDLEY the ATU-C shall enter the state C-REVERB4.

- 450 -

With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure C.18. When
Bitmap-NR is enabled ATU-C transmits the signal in both of NEXTR and FEXTR symbols, and the ATU-R estimates
two SNRs from the received NEXTR and FEXTR symbols, respectively, as defined in Figure C.19.
The following formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S + 271 < a) or (S > d) }then symbol for estimation of FEXTR SNR
if { (S > b) and (S + 271 < c) }then symbol for estimation of NEXTR SNR
where a = 1243, b = 1403, c = 2613, d = 2704
When Bitmap-NR is disabled (FEXT Bitmap mode), the ATU-C only transmits the signal in FEXTR symbols, and the
ATU-R estimates the SNR from the received FEXTR symbols. For modems not using any of the profiles defined in§C.3.4 and modems using Profile 1, the ATU-C shall transmit only the pilot tone as NEXTR symbol. For Profile 3, the
ATU-C shall not transmit any signal in NEXTR symbols. The number of bits of NEXTR shall be no more than thenumber of bits of FEXTR.
For modems that use any of the profiles defined in §C.3.4, the PRDm sequence generator at the transmitter shallcontinue to be updated during NEXTR symbols when Bitmap-NR is disabled (FEXT Bitmap mode).
NOTE -For modems not using any of the profiles defined in §C.3.4, the PRDm sequence generator at thetransmitter is either always updated or always stopped during NEXTR symbol when Bitmap-NR isdisabled (FEXT Bitmap mode). The receiver should be able to support both modes of transmitter
operation.

TTR
TCM-ISDN crosstalkat ATU-R receiver

TCM-ISDN crosstalkat ATU-C receiver

NEXT

NEXT

FEXT

FEXT

FEXT

NEXT

NEXT

NEXT

FEXT

FEXT
Estimation of
Signal-to-Noise ratio

C/R-MEDLEY (49152 symbols)

Bitmap for Downstream

Bitmap-NR

Bitmap-FR

Bitmap-FR

Bitmap-NR

Bitmap for Upstream

Bitmap-FC

Bitmap-NC

Bitmap-NC

Bitmap-FC
T1532890-99

Figure C.18/G.992.1 – Estimation of periodic Signal-to-Noise Ratio- 451 -

TTRC
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

4
5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

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77

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79

80

8

81

82

83

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86

87

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90

9

91

92

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94

95

96

97

98

99

100

101

10 101

102

103

104

105

106

107

108

109

110

111

11

112

113

114

115

116

117

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121

12

122

123

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126

127

128

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131

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132

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14

142

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15

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162

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166

167

168

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17
18

183

184

185

186

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19

193

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197

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244

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25

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26

264

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30

304

305

306

307

308

309

310

311

312

313

315

316

317

318

319

320

321

322

323

324

31

314

32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

Symbol for estimation of FEXTR S/N
Symbol for estimation of NEXTR S/N

Symbol not used for S/N estimation
T1535370-00

Figure C.19/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Downstream
I.7.6.3

C-MSG1 (supplements 10.6.4)- 452 -

Table C.bb/G.992.1 – Assignment of 48 bits of C-MSG1
Suffix(ces) of mi (Note 1)
Parameter (Note 3)
47-44
Minimum required downstream SNR margin at initialization (Note 2)
43-18
Reserved for future use
17
Trellis coding option
16
Overlapped spectrum option (Note 4)
15
Unused (shall be set to "1")
14-12
Reserved for future use
11
NTR
10-9
Framing mode
8-6
Transmit PSD during initialization
5
Reserved
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – A positive number of dB; binary coded 0-15 dB.
NOTE 3 – All reserved bits shall be set to "0".
NOTE 4 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
I.7.6.3.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.6.4.8)

The Ndownmax (transmit) capability shall be binary encoded onto {m4, ..., m0} (e.g. 100012 = 17). The maximum
number of bits for the upstream data, Nupmax, that the ATU-C receiver can support need not be signalled to the ATU-R;
it will be implicit in the bits and gains message, C-B&G, which is transmitted after channel analysis.
C.7.7

Channel analysis (ATU-R) (supplements 10.7)

From R-RATES1 to R-CRC2, the ATU-R shall transmit only the FEXTC symbols and shall not transmit the NEXTC
symbols. In R-SEGUE2 and R-MEDLEY, the ATU-R shall transmit both FEXTC and NEXTC symbols when
Bitmap-NC is enabled (Dual Bitmap mode) and shall not transmit NEXTC symbols when Bitmap-NC is disabled(FEXT Bitmap mode). The duration of each state is defined in Figure C.21.
C.7.8

R-SEGUE1 (supplements 10.7.1)

The maximum duration of R-SEGUE1 is 14 symbols (see Figure C.17).
C.7.8.1

R-REVERB3 (supplements 10.7.2)

The ATU-R shall start R-REVERB3 aligned with the beginning of a Hyperframe.
C.7.8.2

R-SEGUE2 (supplements 10.7.3)

The duration of R-SEGUE2 is 13 symbols.
C.7.8.3

R-MEDLEY (replaces 10.7.8)

R-MEDLEY is a wideband pseudo-random signal used for estimation of the upstream SNR at the ATU-C. The data to
be transmitted are derived from the pseudo-random sequence PRUm defined as:
d n = 1 for n = 1 to 23 and d n = d n-18 ⊕ d n-23 for n> 23.
In contrast to R-REVERB1, the cyclic prefix is used and the data sequence continues from one symbol to the next (i.e.
d1 to d23 are not re-initialized for each symbol). Because the sequence is of length 223-1, and 2*(nn-5) bits are used foreach symbol (where nn is the maximum subcarrier specified for PSD mask EU-nn in Table C.zz), the subcarrier vector
for R-MEDLEY changes from one symbol period to the next. Following R-MEDLEY the ATU-R enters signalling state
R-REVERB4. The duration of R-MEDLEY is as shown in Figure C.26.

- 453 -

With the periodical noise of TCM-ISDN, SNR also changes in the same cycle, as shown in Figure C.18. When
Bitmap-NC is enabled, the ATU-R shall transmit the signal in both of NEXTC and FEXTC symbols, and ATU-C shall
estimate two SNRs from the received NEXTC and FEXTC symbols, respectively, as defined in Figure C.20.
The following numerical formula gives the information that received Ndmt-th DMT symbol belongs to:
For Ndmt = 0, 1, …, 344
S = 272 x Ndmt mod 2760
if { (S > b) and (S + 271 < c) }if { (S + 271 < a) }where a = 1148, b = 1315, c = 2608

then symbol for estimation of FEXTC SNR
then symbol for estimation of NEXTC SNRWhen Bitmap-NC is disabled (FEXT Bitmap mode), the ATU-R only transmits the signal in FEXTC symbols, and the
ATU-C estimates the SNR from the received FEXTC symbols. The number of bits of NEXTC shall be no more than thenumber of bits of FEXTC.
For modems that use any of the profiles defined in §C.3.4, the PRUm sequence generator at the transmitter shallcontinue to be updated during NEXTC symbols when Bitmap-NC is disabled (FEXT Bitmap mode).
NOTE -For modems not using any of the profiles defined in §C.3.4, the PRUm sequence generator at thetransmitter is either always updated or always stopped during NEXTC symbol when Bitmap-NC isdisabled (FEXT Bitmap mode). The receiver should be able to support both modes of transmitter
operation.

- 454 -

TTR R
0

0

1

2

3

4

5

6

7

8

9

1

10

11

12

13

14

15

16

17

18

19

2

20

21

22

23

24

25

26

27

28

29

3

30

31

32

33

34

35

36

37

38

39

40

4

41

42

43

44

45

46

47

48

49

50

5

51

52

53

54

55

56

57

58

59

60

6

61

62

63

64

65

66

67

68

69

70

7

71

72

73

74

75

76

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79

80

8

81

82

83

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86

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88

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9

91

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100

101

10

101

102

103

104

105

106

107

108

109

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112

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115

116

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121

11
12

122

123

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126

127

128

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131

13

132

133

134

135

136

137

138

139

140

141

14

142

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15

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16

162

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17

173

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251

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25

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260

262

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26

264

265

266

267

268

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270

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27

274

275

276

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280

281

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28

284

285

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296

297

298

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300

301

302

303

30

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

31
32

325

326

327

328

329

330

331

332

333

334

33

335

336

337

338

339

340

341

342

343

344

T1535290-00

Symbol for estimation of FEXT C S/N

Symbol not used for S/N estimation

Symbol for estimation of NEXT C S/N

Figure C.20/G.992.1 – Symbol pattern in a hyperframe for S/N estimation – Upstream
C.7.8.4

R-MSG1 (supplements 10.7.6)- 455 -

Table C.cc/G.992.1 – Assignment of 48 bits of R-MSG1
Parameter (Note 2)
Suffix(ces) of mi (Note 1)
47-18
Reserved for future use
17
Trellis coding option
16
Overlapped spectrum option (Note 3)
15
Unused (shall be set to "1")14
Support of S = 1/2 mode (see I.4.9) (Note 4)
13
Support of dual latency downstream
12
Support of dual latency upstream
11
Network Timing Reference
10, 9
Framing mode
8-5
Reserved for future use
4-0
Maximum numbers of bits per subcarrier supported
NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
NOTE 3 – The initialization sequence allows for interworking of overlapped and non-overlapped spectrum
implementations. Therefore, this indication is for information only.
NOTE 4 – Since the S=1/2 mode is mandatory for Annex C-EU, a modem supporting Annex C-EU shall set this bit tobinary ONE.

C.7.8.4.1

Maximum numbers of bits per subcarrier supported – Bits 4-0 (replaces 10.7.6.6)

The Nupmax (transmit) capability is encoded onto {m4 , ..., m0} with a conventional binary representation (e.g.
100012 = 17).
C.7.9

Exchange – ATU-C (supplements 10.8)

During C-RATESn, C-MSGn, C-B&G, and C-CRCn, the ATU-C shall transmit the FEXTR symbol. In the other signals,
the ATU-C shall transmit both FEXTR and NEXTR symbols when Bitmap-NR is enabled (Dual Bitmap mode), and,for modems not using any of the profiles defined in §C.3.4 and modems using Profile 1, shall not transmit the NEXTR
symbols except pilot tone when Bitmap-NR is disabled (FEXT Bitmap mode). For Profile 3, the ATU-C shall nottransmit any signal in NEXTR symbols. The duration of each state is defined in Figure C.22.
C.7.9.1

C-MSG2 (supplements 10.8.9)

Replace Table 10-13 with Table C.dd.

Table C.dd/G.992.1 – Assignment of 32 bits of C-MSG2
Suffix(ces) of mi (Note 1)

Parameter (Note 2)

31-26

Estimated average loop attenuation

25-21

Reserved for future use

20-16

Performance margin with selected rate option

15-11

Reserved for future use

10-0

Total number of bits supported

NOTE 1 – Within the separate fields the least significant bits have the lowest subscripts.
NOTE 2 – All reserved bits shall be set to "0".
For modems not using any of the profiles defined in §C.3.4 and modems using Profiles 1, 2, 4, 5 or 6 :For NSCus=32:
n1C-MSG2 = 43
n2C-MSG2 = 91

- 456 -

Otherwise,
n1C-MSG2 = 91
n2C-MSG2 = 139
For Profile 3:
n1C-MSG2 = 13
n2C-MSG2 = 25
C.7.9.1.1

Total number of bits per symbol supported (replaces 10.8.9.3)

The ATU-C receiver shall also calculate the maximum number of bits per symbol that the upstream channel can support−7

with the performance margin defined in C-MSG-RA at an error rate of 10 .
The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTC and
NEXTC downstream channel performance [e.g. if the maximum numbers of bits that can be supported in FEXTC and
NEXTC symbols are 111 and 88 {Total number of bits per symbol supported} = (111 x 126 + 88 x 214)/340 = 96].
This number is encoded into bits 10-0 using a conventional binary representation [e.g. if the maximum number of bitsthat can be supported is 96 (data rate = 384 kbit/s), {m10, ..., m0} = 000011111112].
NOTE – The number of symbols per hyperframe is 340. The number of FEXT symbols is 126. The number of NEXTsymbols is 214.
C.7.9.2

C-B&G (replaces 10.8.13)

C-B&G shall be used to transmit to the ATU-R the bits and gains information, Bitmap-FC {b1, g1, b2, g2, ... bNSCus-1,
gNSCus-1}, and Bitmap-NC {bNSCus+1, gNSCus+1, bNSCus+2, gNSCus+2, ..., b2*NSCus-1, g2*NSCus-1}, that are
to be used on the upstream carriers. bi of Bitmap-FC indicates the number of bits to be coded by ATU-R transmitter
onto the i th upstream carrier in FEXTC symbols; gi of Bitmap-FC indicates the scale factor, relative to the gain thatwas used for that carrier during the transmission of R-MEDLEY, that shall be applied to the i th upstream carrier in
FEXTC symbols. Similarly, bi of Bitmap-NC indicates the number of bits onto the (i – NSCus) th upstream carrier in
NEXTC symbols; gi of Bitmap-NC indicates the scale factor that shall be applied to the (i – NSCus) th upstream carrierin NEXTC symbols.
Because no bits or energy will be transmitted at DC or one-half the sampling rate, b0, g0, bNSCus, gNSCus, b2*NSCus,
and g2*NSCus are all presumed to be zero and shall not be transmitted.
Each bi shall be represented as an unsigned 5-bit integer, with valid bis lying in the range of zero to Nupmax, themaximum number of bits that the ATU-R is prepared to modulate onto any subcarrier, which is communicated in
R-MSG1.
Each gi shall be represented as an unsigned 11-bit fixed-point quantity, with the binary point assumed just to the right of
the third most significant bit. For example, a gi with binary representation (most significant bit listed first)
001.010000002 would instruct the ATU-R to scale the constellation for carrier i, by a gain factor of 1.25, so that thepower in that carrier shall be 1.94 dB higher than it was during R-MEDLEY.
For subcarriers on which no data are to be transmitted, and the receiver will never allocate bits (e.g. out-of-band
subcarriers) both bi and gi shall be set to zero (000002 and 00000000 0002, respectively). For subcarriers on which nodata are to be currently transmitted, but the receiver may allocate bits later (e.g. as a result of an SNR improvement), thebi shall be set to zero and the gi to a value in the 0.19 to 1.33 range (000.001100002 to 001.010101012).
Let NSCu=128, except when EU-32 is used where NSCu=32. The C-B&G information shall be mapped in a32*(NSCu-1)-bit (4*(NSCu-1) byte, the same number of FEXTR symbols. When NSCu=32, including C_CRC5, thetotal length is 336 symbols while for NSCu=128, the total length is 336+3*345=1371 symbols) message m defined by:- 457 -

m = {m32*(NSCu-1)-1, m32*(NSCu-1)-2, …, m1, m0} = { g2*NSCu-1, b2*NSCu-1, …, g NSCu+1, b NSCu+1, g(C.10-2)
NSCu-1, b NSCu-1, …, g1, b1},
with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in
4*(NSCu-1) symbols, using the transmission method as described in 10.8.9.
When Bitmap-NC is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NC shall be set to zero.
For index between NSCus+1 and 127, the m values are set to 0.
C.7.9.3

C-SEGUE3 (replaces 10.8.16)

The duration of C-SEGUE3 is 18 symbols. Following C-SEGUE3, the ATU-C completes the initialization and enters
C-SHOWTIME. In C-SHOWTIME, ATU-C shall transmit the signal using Bitmap-FR and Bitmap-NR with the sliding
window.
When Bitmap-NR is disabled (FEXT Bitmap mode), for modems not using any of the profiles defined in §C.3.4 andmodems using Profile 1, the ATU-C shall transmit only the pilot tone as NEXTR symbols. For Profile 3, the ATU-C
shall not transmit any signal in NEXTR symbols.
C.7.10Exchange – ATU-R (supplements 10.9)

ATU-R shall transmit only the FEXTC symbols in R-MSGn, R-RATESn, R-B&G, R-CRCn. In other signals, the
ATU-R shall transmit both FEXTC and NEXTC symbols when Bitmap-NC is enabled (Dual Bitmap mode) and shallnot transmit NEXTC symbols when Bitmap-NC is disabled (FEXT Bitmap mode). The duration of each state is definedin Figure C.22.
C.7.10.1

R-MSG-RA (supplements 10.9.2)

Replace Table 10-15 with Table C.7.
Table C.7/G.992.1 – Assignment of 80 bits of R-MSG-RA (Annex C-EU)
Suffix(ces) of mi(Note)
79-68
67-56
55-49
48-40
39-32
31-25
24-21
20-16
15-14
13-12
11-0

Parameter
All reserved bits shall be set to 0
Reserved for ITU-T
Bfast-max
Number of RS overhead bytes, (R)
Number of RS payload bytes, K
Number of tones carrying data (ncloaded)
Estimated average loop attenuation
Coding gain
Performance margin with selected rate option
Reserved for ITU-T
Maximum Interleave Depth downstream
Total number of bits per DMT symbol, Bmax

NOTE – Within the separate fields the least significant bits have the lowest subscripts.

C.7.10.1.1

Total number of bits supported (Bmax) (replaces 10.9.2.8)

This parameter shall be defined as in R-MSG2, see C.7.9.1.
C.7.10.1.2

Bfast-max (new)- 458 -

Bfast-max is the maximum number of bits of the fast buffer for fast data transmitted on the condition that the bits of thefast data can be equally assigned to all FEXT-symbols and NEXT-symbols.
Fast Buffered Data Bfast-max is tf.
C.7.10.2

R-MSG2 ( supplements 10.9.8)

N1R-MSG2 = 10
N2R-MSG2 = 20
C.7.10.2.1

Total number of bits per symbol supported (supplements 10.9.8.3)

The maximum number of bits per symbol is defined at the reference point B, that is calculated from the FEXTR and
NEXTR downstream channel performance. For example, if the maximum numbers of bits that can be supported in
FEXTR and NEXTR symbols are 111 and 88, the total number of bits per symbol supported is (111 x 126 + 88 x
214)/340 = 96.
NOTE – The number of symbols per hyperframe is 340, the number of FEXT symbols is 126, and the number of NEXTsymbols is 214.

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C.7.10.3 R-REVERB5 (supplement of 10.9.12)
The duration of R-REVERB5 is 345n-40, 3<=n<=19, when NSCu=128, or 3<=n<=16 when NSCu=32.
C.7.10.4 R-B&G (replaces 10.9.14)
The purpose of R-B&G is to transmit to ATU-C the bits and gains information, Bitmap-FR {b1, g1, b2, g2, ..., b255,g255}, and Bitmap-NR {b257, g257, b258, g258, ..., b511, g511}, to be used on the downstream subcarriers. bi ofBitmap-FR indicates the number of bits to be coded by ATU-C transmitter onto the i th downstream subcarrier in
FEXTR symbols; gi of Bitmap-FR indicates the scale factor that shall be applied to the i th downstream subcarrier in
FEXTR symbols, relative to the gain that was used for that carrier during the transmission of C-MEDLEY. Similarly, bi
of Bitmap-NR indicates the number of bits onto the (i – 256) th downstream carrier in NEXTR symbols; gi ofBitmap-NR indicates the scale factor that shall be applied to the (i – 256) th downstream carrier in NEXTR symbols.
Because no bits or energy will be transmitted at DC or one-half the sampling rate, b0, g0, b256, g256, b512, and g512
are all presumed to be zero, and are not transmitted. When subcarrier 128 is reserved as the pilot tone, b128 and b384
shall be set to 0, and, for modems not using any of the profiles defined in §C.3.4 and modems using Profiles 1, 2, 4, 5 or
6, g128 and g384 shall be set to gsync. For Profile 3, g128 shall be set to gsync and g384 shall be set to 0. Whensubcarrier 96 is reserved as the pilot tone, b96 and b352 shall be set to 0, and, for modems not using any of the profiles
defined in §C.3.4 and modems using Profiles 1, 2, 4, 5 or 6, g96 and g352 shall be set to gsync. For Profile 3, g96 shallbe set to gsync and g352 shall be set to 0. When subcarrier 64 is reserved as the pilot tone, b64 and b320 shall be set to0, and, for modems not using any of the profiles defined in §C.3.4 and modems using Profiles 1, 2, 4, 5 or 6, g64 andg320 shall be set to gsync. For Profile 3, g64 shall be set to gsync and g320 shall be set to 0. When subcarrier 48 isreserved as the pilot tone, b48 and b304, shall be set to 0, and, for modems not using any of the profiles defined in§C.3.4 and modems using Profiles 1, 2, 4, 5 or 6, g48 and g304 shall be set to gsync. For Profile 3, g48 shall be set to
gsync and g304 shall be set to 0. When subcarrier 32 is reserved as the pilot tone, b32 and b288, shall be set to 0, and,for modems not using any of the profiles defined in §C.3.4 and modems using Profiles 1, 2, 4, 5 or 6, g32 and g288
shall be set to gsync. For Profile 3, g32 shall be set to gsync and g288 shall be set to 0. When subcarrier 16 is reserved
as the pilot tone, b16 and b272, shall be set to 0, and, for modems not using any of the profiles defined in §C.3.4 andmodems using Profiles 1, 2, 4, 5 or 6, g16 and g272 shall be set to gsync. For Profile 3, g16 shall be set to gsync andg272 shall be set to 0. The value gsync represents the gain scaling applied to the sync symbol.
The R-B&G information shall be mapped in a 8160-bit (1020 byte) message m defined by:
m = {m8159, m8158, …, m1, m0} = { g511, b511, …, g257, b257, g255, b255, …, g1, b1},

(C.10-3)

with the MSB of bi and gi in the higher m index and m0 being transmitted first. The message m shall be transmitted in
1020 symbols, using the transmission method as described in 10.9.8.
When Bitmap-NR is disabled (FEXT Bitmap mode), bi and gi of Bitmap-NR shall be set to zero.
C.7.10.5

R-SEGUE5 (replaces 10.9.17)

The duration of R-SEGUE5 is 13 symbols. Following R-SEGUE-5, ATU-R completes the initialization and enters
R-SHOWTIME. In R-SHOWTIME, ATU-R shall transmit the signal using Bitmap-FC and Bitmap-NC with the sliding
window.
When Bitmap-NC is disabled (FEXT Bitmap mode), ATU-R shall not transmit NEXTC symbols.

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ATU-CC-FLAG2(G.994.1)

C-GALF2(G.994.1)≥ 128≤ 2048C-QUIET2(Note 5)345n(n ≤ 38)

ATU-R

If R-ACK2then
C-PILOT1

If R-ACK1then
C-PILOT1AR-GALF2(G.994.1)

Beginning ofHyperframe

R-QUIET2≤ 15500

345n(1 ≤ n ≤ 33)≤ 32
Beginning ofHyperframe

1725

C-QUIET3A(Note 2)

R-FLAG2(G.994.1)

R-REVERB1
1536

C-REVERB1
12477(Note 5)9216

C-PILOT2(Note 4)

1536

C-ECT

(Note 2)

(Note 5)4608

C-REVERB2

1536

If R-ACK2 then C-PILOT3
If R-ACK1 then C-QUIET53628

C-REVERB3

20

C-SEGUE1

2884

C-RATES1/C-CRC1
C-MSG1/C-CRC2

Last symbol
may beshortened byn samples

R-QUIET3≥ 6144≤ 6145

R-ECT

1536

R-REVERB2≥ 3634≤ 3643

R-SEGUE1

5 ≤, ≤ 14(Note 2)

(Note 1)Introduction ofguard time

R-REVERB3
345n + 208(0 ≤ n ≤ 7)

49152
C-MEDLEY

345n - 13(9 ≤ n ≤ 16)
R-SEGUE2

13

R-RATES1/R-CRC1
R-MSG1/R-CRC2

1254

R-MEDLEY

49152(Note 3)(Note 2)

T1532900-99

Figure C.21/G.992.1 – Timing diagram of the initialization sequence – Part 1- 461 -

(Note 4)NOTE 1 – The ATU-C shall transmit the FEXTR symbols, and shall not transmit as NEXTR symbols except the pilot
tone.
NOTE 2 – The ATU-C shall transmit both FEXTR and NEXTR symbols, when Bitmap-NR is enabled (Dual Bitmapmode).
ATU-C shall not transmit the NEXTR symbols except pilot tone, when Bitmap-NR is disabled (FEXT Bitmap mode).
NOTE 3 – The ATU-R shall transmit the FEXTC symbols, and shall not transmit the NEXTC symbols.
NOTE 4 – The ATU-R shall transmit both FEXTC symbols, when Bitmap-NC is enabled (Dual Bitmap mode). ATU-R
shall
not transmit NEXTC symbols, when Bitmap-NC is disabled (FEXT Bitmap mode).
NOTE 5 – The ATU-C shall transmit both FEXTR and NEXTR symbols.

- 462 -

Figure C.22/G.992.1 – Timing diagram of the initialization sequence – Part 2[Editor’s note: updated Figure C.22 to parameterize the length of C-B&G and the maximum length of R-REVERB5.]

C.8

AOC On-line adaptation and reconfiguration (pertains to clause 11)

C.8.1.1

Bit swap request (replaces 11.2.3)

The receiver shall initiate a bit swap by sending a bit swap request to the transmitter via the AOC channel. This request
tells the transmitter which subcarriers are to be modified. The format of the request is shown in Table C.8.

Table C.8/G.992.1 – Format of the bit swap request message
Message header{111111112}(8 bits)

Bitmap index(1 bit)Message field 1-4
CommandSubchannel index(7 bits)(8 bits)

The request shall comprise nine bytes as follows:• an AOC message header consisting of 8 binary ones;• message fields 1-4, each of which consists of one-bit bitmap index, a seven-bit command followed by a related
eight-bit subchannel index. One-bit bitmap index and valid seven-bit commands for the bit swap message shallbe as shown in Table C.9. In Table C.9, the MSB for the bit swap request command represents the Bitmap index.
For downstream data, Bitmap index equals 0 indicates Bitmap-FR, and Bitmap index equals 1 indicates
Bitmap-NR. Similarly for upstream data, Bitmap index equals 0 indicates Bitmap-FC, and 1 indicates
Bitmap-NC. The eight-bit subchannel index is counted from low to high frequencies with the lowest frequency
subcarrier having the number zero. The subcarrier index zero shall not be used;• the bit swap between FEXTC/R symbols and NEXTC/R symbols is not allowed.

Table C.9/G.992.1 – Bit swap request commandValue(8 bit)y00000002

Interpretation
Do nothingy00000012
y00000102

Increase the number of allocated bits by one

y00000112
y00001002

Increase the transmitted power by 1 dB

y00001012
y00001102

Increase the transmitted power by 3 dB

y00001112
y0001xxx2

Reduce the transmitted power by 2 dB

Decrease the number of allocated bits by one
Increase the transmitted power by 2 dB
Reduce the transmitted power by 1 dB
Reserved for vendor discretionary commands

NOTE – y is "0" for FEXTC/R symbols, and "1" for NEXTC/R symbols of the Sliding Window.
The bit swap request message (i.e. header and message fields) shall be transmitted five consecutive times.
To avoid gi divergence between ATU-C and ATU-R after several bit swaps, for a gi update of ∆ dB the new gi value
should be given by:

g i ' = (1 / 512) × round (512 × g i × 10 exp(∆ / 20))

- 463 -

(C.11-1)

C.8.1.2

Extended bit swap request (supplements 11.2.4)

The format of the extended bit swap request is shown in Table C.10.

Table C.10/G.992.1 – Format of the bit swap request message
Message header{111111002}(8 bits)

Bitmap index(1 bit)Message field 1-6
CommandSubchannel index(7 bits)(8 bits)

In the same manner as the bit swap request, each of the massage fields of the extended bit swap request consists of
one-bit bitmap index, a seven-bit command followed by a related eight-bit subchannel index.
C.8.1.3

Bit swap acknowledge (supplements 11.2.5)

The bit swap superframe counter number shall only indicate the last superframe (SPF#4) of a hyperframe.
The new bit and/or transmit power table(s) shall then take effect starting from the first frame (frame 0) of SPF#0 of a
hyperframe.
If the bit swap superframe counter number contained in the received bit swap acknowledge message does not indicate
SPF#4, then the new table(s) shall take effect starting from frame 0 of SPF#0 of the next hyperframe.

- 464 -