EXHIBIT 15

Case 1:20-cv-22051-JEM Document 1-18 Entered on FLSD Docket 05/15/2020 Page 1 of 20
(12) United States Patent 

Kim et al. 

US007215653B2 

US 7.215,653 B2 

May 8, 2007 

(10) Patent No.: 

(45) Date of Patent: 

(54) CONTROLLING DATA TRANSMISSION 

RATE ON THE REVERSE LINK FOR EACH 

MOBILE STATION IN ADEDICATED 

MANNER 

(75) Inventors: Ki Jun Kim, Seoul (KR); Young Cho 

Kim, Seoul (KR); Young Jo Lee, 

Kunpo (KR); Jong Hoe An, Anyang 

(KR); Young Woo Yun, Seoul (KR): 

Young Jun Kim, Anyang (KR) 

(73) Assignee: LG Electronics Inc., Seoul (KR) 

(*) Notice: Subject to any disclaimer, the term of this 

patent is extended or adjusted under 35 

U.S.C. 154(b) by 962 days. 

(21) Appl. No.: 10/071,243 

(22) Filed: Feb. 11, 2002 

(65) Prior Publication Data 

US 20O2/O141349 A1 Oct. 3, 2002 

(30) Foreign Application Priority Data 

Feb. 12, 2001 (KR) ...................... 10-2001-OOO6839 

Jul. 10, 2001 (KR) ...................... 10-2001-0041363 

Sep. 18, 2001 (KR) ...................... 10-2001-00576OO 

(51) Int. Cl. 

H04O 700 (2006.01) 

(52) U.S. Cl. ........................ 370/329; 370/332:455/68; 

455/69 

(58) Field of Classification Search ..................... None 

See application file for complete search history. 

(56) References Cited 

U.S. PATENT DOCUMENTS 

5,603,096 A * 2/1997 Gilhousen et al. ............ 455/69 

A. 

RECEPTION 

PROCESSOR 

RATE CONTROLLER 

TRANSMISSION DATA 

6,069,883. A * 

6,389,034 B1* 

5/2000 EZak et al. ................ 370,335 

5/2002 Guo et al. ..... ... 370,441 

6,411,799 B1* 6/2002 Padovani .......... - - - - - - - - 455.69 

6,741,862 B2 * 5/2004 Chung et al. ............ 455,452.1 

6,996,127 B2 * 2/2006 Rezaiifar et al. ........... 370/468 

FOREIGN PATENT DOCUMENTS 

EP O 767 548 A2 4f1997 

EP 1 003 302 A2 5, 2000 

EP 1 067 729 A2 1, 2001 

EP 1067729 * 1?2OO1 

GB 2269296 A * 2, 1994 

WO WO 98.24199 6, 1998 

WO WOOOf 14900 * 3f2OOO 

* cited by examiner 

Primary Examiner Huy D. Vu 

Assistant Examiner—Robert W. Wilson 

(74) Attorney, Agent, or Firm—Fleshner & Kim, LLP 

(57) ABSTRACT 

The data transmission rate on the reverse link in a mobile 

communications system is controlled by determining an 

interference level at a base station due to signals from all 

mobile stations served by the base station, and determining 

a transmission energy level required for each mobile station. 

The interference level is compared with the transmission 

energy level to obtain a comparison result for each mobile 

station, and each mobile adjusts its data transmission rate 

based upon the comparison result, which is sent via a common channel on a forward link to each mobile station in 

a dedicated manner. Thereafter, packet data is transmitted on 

the reverse link in accordance with the adjusting so that data 

throughput can be maximized. 

40 Claims, 8 Drawing Sheets 

TRANSMSSION DATA 

CONTROL COMMAND TRANSMISSION 

PROCESSOR 

 

 

 

 

 

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U.S. Patent May 8, 2007 Sheet 1 of 8 US 7.215,653 B2 

F. G. 1 

PRIOR ART 

10 11 

BIT REPETITION 

WALSH COVER 

SIGNAL POINT MAPPNG 

O => +1 

1 => -1 

RAB 

 

 

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U.S. Patent May 8, 2007 Sheet 2 of 8 US 7.215,653 B2 

A4 

RECEPTION 

PROCESSOR 

COMPARATOR INTERFERENCE E TRANSMISSION 

LEVEL, DETECTOR (YES f PROCESSOR 

 

 

 

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U.S. Patent May 8, 2007 Sheet 3 of 8 US 7.215,653 B2 

FG. 4 

SYMBO f 1 SLOT F N=12 

SYMBO 2 SLOTS F N=24 

n=16 FF N=12 SYMEO ( 4 SLOTS EF N=48 

=8 F N=24 1 SYMBOL | 8 SLOTS IFN-96 NITIAL OFFSE VALUES AR DATA BATE - 

n=2 

=4 F 

FN-96 N=48 a; SYMBOL | 16 SLOTS IF N=192 ASSIGNED TO EACH USER OF - - in 41 43 44 1.2 KBPS F N=24 

n=1 F N=192 2.4 KBPS F N=48 

RATE-CONTROL BITS SGNAL POINT MAPPNG 4.8 KBPS F Ne96 

FOR USER O (ORN) FEETO O- +1, 1--- CNEL 9.6 KBPS F N=192 

(1 B f 20 MS) NO SYMBOL -- 0 

MUX X : 

RATE-CONTRO BITS 

FOR USER N-1 (CR 2N-1) FEFTOR sign,ON: up NG CNEL 

(1 BiT 20 MS) NO SYMEOL-- 0 45 

T46 T47TT 48 

RELATIVE 

OFFSET 

LONG CODE 

GENERATOR 

(1.2288 MCPS) 

N IS THE NUMBER OF 

USERS NEACH ARM DECIMATOR CALCULATION 

LONG CODE MASK 

SIGNAL POINT MAPPNG 

O -- +1, 1 - - RATE-CONTROL BITS FOR USER O (ORN) 

(1 BIT f 20 MS) 

RATE-CONTROL BITS 

FOR USER N-1 (OR 2N-1) 

(1 BT 20 MS) 

REPEATOR 

nX 

REPEATOR O - +1, NO SYMBOL-- 0 

NC SYBO -- O 

-- -1 

1 SYMBOL ( 1 SLOT IF N=12 

1 SYMBOL f 2 SLOTS F N-24 

1 SYMBOL f 4 SLOTS F N=48 

1 SYMBOL / 8 SLOTS F N=96 

1 SYMBOL / 16 SOTS F N=192 

MUX 

CHANNEL 

GAN 

NITAL OFFSET VALUES 

ASSIGNED TO EACH USER 

Q-ARDAA RATE = 0.6 KBPS F N-12 

12 KBPS F N=24 

4 KBPS F N=48 

4.8 KBPS FN-96 

96 KBPS F N=192 

 

 

 

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U.S. Patent May 8, 2007 Sheet 4 of 8 US 7.215,653 B2 

F.G. 5 

BS DETERMINES INTERFERENCE LEVEL 

OF ALL TRAFFIC CHANNELS 

S51 

COMPARE INTERFERENCE LEVEL 

WITH THRESHOLD WALUE 

DETERMINE REVERSE LINK LOAD 

S52 

DETERMINE DATA TRANSMISSION RATE ADJUSTMENT S54 

AND TRANSMISSION CHANNEL FOR EACH MS 

BASED ON REVERSE NK LOAD AND 

DISTANCE BETWEEN MS AND BS 

TRANSMIT TO MS S55 

 

 

 

 

 

 

 

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U.S. Patent May 8, 2007 Sheet 5 of 8 US 7.215,653 B2 

F.G. 6 

DETERMINE TRANSMISSION ENERGY LEVEL S62 

REQUIRED FOR EACH MS 

DETERMNE INTERFERENCE LEVELAT BS S60 

DUE TO S GNAES FROM MS 

COMPARE INTERFERENCE LEVEL WITH TRANSMISSION ENERGY LEVEL S64 

TO OBTAN A COMPARISON RESULT FOR EACH MS 

SEND COMPARISON RESULT WA A COMMON CHANNEL S66 

ON A FORWARD LNK TO EACH MS IN A DEDICATED MANNER 

ADJUST DATA TRANSMISSION RATE FOR EACH MS S68 

BASED UPON THE COMPARISON RESULT 

TRANSMIT PACKE DATA ON REVERSE LINK -$69 

 

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U.S. Patent May 8, 2007 Sheet 6 of 8 US 7.215,653 B2 

F. G. 7 

BS 

CALCULATE MS PRI S70 

OR RECEIVE FROM MS 

S71 

CALCULATE MS RCW 

DETERMINE TOTAL INTERFERENCE S72 

RECEIVED ATBS 

MS 

GENERATE RCB FOR EACH MS 

USING MS RCW AND MS TAB TRANSMIT MSAB S73 

RECEIVE RCB FROM ALL ACTIVE BS S 

S74 

TRANSMT RCB TO EACH MS 

GENERATE COMBINED RCB TO CONTROL 

76 

REVERSE LINK DATA RATE S77 

 

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U.S. Patent May 8, 2007 Sheet 7 of 8 US 7,215,653 B2 

FG. 8 

TOTAL INTERFERENCE 

(ROT) BS RCW = BS RCW - A2 

UNCHANGED 

BS RCW = BS RCV + A 

FG 9 

COMPARE MS RCW, BS RCW, 

MS AB CONDITIONS 

MS RCW +A< BS RCW 

& 

MS AB = INCREASE MS RCV > BS RCW 

S33 

NCREASE UNCHANGED DECREASE 

 

 

 

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U.S. Patent May 8, 2007 Sheet 8 of 8 US 7,215,653 B2 

FIG 10 

BS 

CALCULATE MS PR S100 

OR RECEIVE FROM MS 

CALCULATE MS RCW S102 

DETERMINE TOTAL INTERFERENCE S104 

RECEIVED ATBS 

UPDATE BS RCV ACCORDING TO S106 

TOTAL INTERFERENCE (ROT) 

S110 MS 

S108 

GENERATE RCB FOR EACH MS O TRANSMT MS AB 

USING MS RCW AND MS AB - 

S112 S114 

RECEIVE RCB FROM 

ALL ACTIVE BS 

S116 

GENERATE COMBINED RCB TO 

CONTROL REVERSE LINK DATA RATE 

TRANSMT RCB TO EACH MS 

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US 7,215,653 B2 

1. 

CONTROLLING DATA TRANSMISSION 

RATE ON THE REVERSE LINK FOR EACH 

MOBILE STATION IN ADEDICATED 

MANNER 

FIELD OF THE INVENTION 

The present invention generally relates to mobile (or 

wireless) communications, and in particular, to controlling 

data transmission (transfer) rates between a base station and 

mobile stations served by the base station so that data 

throughput is advantageously increased. 

BACKGROUND OF THE INVENTION 

Mobile communications involve, among various process ing procedures, signal transmissions and handling of data 

traffic between an access network (AN) and an access 

terminal (AT). An access network (AN) comprises many 

elements, one of which being a base station, as known by 

those skilled in the art. An access terminal (AT) can be in 

many forms, including a mobile station (e.g., a mobile 

phone), a mobile terminal (e.g., a laptop computer), and 

other devices (e.g., a personal digital assistant: PDA) having 

the combined functionality of both a mobile station and a 

mobile terminal, or having other terminal capabilities. Here 

inafter, an access terminal (AT) will be referred to as a 

“mobile” for the sake of brevity. 

In a conventional mobile communications system, a plu rality of mobiles (e.g., cellular phones, portable computers, 

etc.) are served by a network of base stations, which serve 

to allow the mobile stations to communicate with other 

components in the communications system. Various types of 

mobile communications systems are known, including Code 

Division Multiple Access (CDMA), time division multiple 

access (TDMA), frequency division multiple access 

(FDMA), and various enhancements and improvements 

thereto which are generally referred to as next generation 

mobile communications systems. 

CDMA is most widely accepted and continues to develop 

and evolve. In particular, CDMA technology evolution (such 

as the so-called “cdma2000' technology or other next gen eration CDMA systems) will provide integrated voice with 

simultaneous high-speed packet data, video and video con 

ferencing capabilities. Currently, the third generation (3G) 

evolution of cdma2000 1x wireless communications is being reviewed or partially adopted by certain standards bodies, 

such as 3GPP and 3GPP2 (The Third Generation Partnership Project 2). 

For example, a baseline framework for cdma2000 1xEV 

DV (1xEVolution Data and Voice) was recently reached by 

the 3GPP2. The 1xEV-DV Standard will be backward com 

patible with existing CDMA IS-95A/B and CDMA2000 1x 

systems, allowing various operators seamless evolution for 

their CDMA systems. Other types of systems that are 

evolving from CDMA include High Data Rate (HDR) 

technologies, 1xEvolution Data Only (1xEV-DO) tech 

nologies, and the like, which will be explained in more detail 

hereinafter. 

The present disclosure focuses on data transmission tech 

niques between base stations and mobiles. Thus, a detailed 

description of additional components, elements and process ing procedures (not specifically mentioned herein) have 

been omitted so that the features of the present invention are 

not obscured. One skilled in the art would have understood 

that various other components and techniques associated 

with base stations and mobiles already known in the art but 

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not described in detail herein, are also part of the present invention. For example, specific details of the protocol 

architecture having an air interface with a layered structure, physical layer channels, protocol negotiation and process 

ing, and the like have been omitted. 

In a communications system, a set of “channels' allow 

signals to be transmitted between the access network (e.g., 

a base station) and the access terminal (e.g., a mobile) within 

a given frequency assignment. Channels consist of “forward 

channels' and “reverse channels.” 

Signal transmissions (data transmissions or transfers) 

from the base station to a mobile via a downlink (i.e., 

forward channels) are commonly referred to as the “forward 

link,' while signal transmissions from the mobile to the base 

station via an uplink (i.e., reverse channels) are commonly 

referred to as the “reverse link.” 

So-called “physical layers' provide the channel structure, 

frequency, power output, modulation, and encoding speci 

fications for the forward and reverse links. The “forward 

channels' consist of those physical layer channels transmit 

ted from the access network to the access terminal, and 

“reverse channels' consist of those physical layer channels 

transmitted from the access terminal to the access network. 

Of the many portions of the forward and reverse channels, 

the “forward MAC channel’ is the portion of the forward 

channel dedicated to medium access control (MAC) activi 

ties. The forward MAC channel consists of the reverse 

power control (RPC) channel, the reverse activity (RA) 

channel, and other channels. Here, the forward MAC reverse 

activity (RA) channel indicates the activity level (e.g., the 

load) on the reverse channel. 

In the so-called Interim Standard 95A (IS-95A) systems, 

the forward link and the reverse link are allocated separate frequencies and are independent of one another. For code 

division multiple access (CDMA) technology is the basis for 

Interim Standard 95 (IS-95) and can operate in both the 

800-MHz and 1900-MHz frequency bands. In CDMA sys 

tems, communications between users are conducted through 

one or more cells/sectors, which are serviced by base 

stations. A user of a first mobile communicates with another 

user on a second mobile by transmitting voice and/or data on 

the reverse link to a cell/sector. The cell/sector receives the 

data for routing to another cell/sector or a public switched 

telephone network (PSTN). If the second user is on a remote 

station, the data is transmitted on the forward link of the 

same cell/sector, or a second cell/sector, to the second 

remote station. Otherwise, the data is routed through the 

PSTN to the second user on the standard phone system. 

A mobile communications system can employ connec 

tionless network services in which the network routes each 

data packet individually, based on the destination address 

carried in the packet and knowledge of current network 

topology. The packetized nature of the data transmissions 

from a mobile allows many users to share a common 

channel, accessing the channel only when they have data to 

send and otherwise leaving it available to other users. The 

multiple access nature of the mobile communications system makes it possible to provide Substantial coverage to many 

users simultaneously with the installation of only one base 

station in a given sector. 

The transfer of digital data packets differs from the 

transfer of digital voice information. Full duplex (simulta 

neous two-way) Voice communication patterns imply that 

the data, transferred between the base station and a particular mobile station, are real-time and Substantially equal in 

bandwidth. It has been noted that a total delay of 200 msec 

(about 2. Kbits of digital data for most speech vocoders) 

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US 7,215,653 B2 

3 

represents intolerable latency within a voice channel. On the 

other hand, transfer of digital data packets is typically asymmetrical, with many more packets being sent from the 

base station to a particular mobile via a downlink (the 

forward link), than from the mobile to the base station via an 

uplink (the reverse link). 

In high speed data packet transfers, users appear to be 

tolerant of data transfer latencies or delays, with latencies of 

up to 10 seconds being encountered in current wireless data 

systems. While such delays appear to be tolerated by the 

user, the delays, attributable to relatively low effective data 

transfer rates, are undesirable. One proposed solution, 

known as “CDMA/HDR' (Code Division Multiple Access/ 

High Data Rate), uses various techniques to measure chan 

nel data transfer rate, to carry out channel control, and to 

mitigate and Suppress channel interference. 

Conventional CDMA systems must handle both voice and 

data. To handle voice signals, the delay between the time 

that information is sent and the time that the information is 

received must be kept relatively short. However, certain 

communications systems used mostly for handling data 

packets can tolerate relatively longer delays or latencies 

between the time that information is sent and the time that 

the information is received. Such data handling communi 

cations systems can be referred to as High Data Rate (HDR) 

systems. The following description will focus on HDR 

systems and techniques, but those skilled in the art would 

understand that various other mobile communications sys 

tems and techniques for handling high data rates, such as 

1xEV-DO, 1xEV-DV, and the like, fall within the scope of 

the present disclosure. 

In general, a High Data Rate (HDR) system is an Internet 

protocol (IP) based system that is optimized for transmitting 

data packets having bursty characteristics and not sensitive 

to latencies or delays. In HDR systems, a base station is 

dedicated to communicating with only one mobile station at 

any one time. An HDR system employs particular tech 

niques allowing for high-speed data transfers. Also, HDR 

systems are exclusively used for high-speed data transfers 

employing the same 1.25 MHz of spectrum used in current 

IS-95 systems. 

The forward link in an HDR system is characterized in 

that the users are not distinguished in terms of orthogonal 

spreading codes, but distinguished in terms of time slots, 

whereby one time slot can be 1.67 ms (milliseconds). Also, 

on the forward link of an HDR system, the mobile (access 

terminal AT) can receive data services from about at least 

38.4. Kbps to about at most 2.4576 Mbps. The reverse link 

of an HDR system is similar to the reverse link of an IS-95 

system, and employs a pilot signal to improve performance. 

Also, traditional IS-95 power control methods are used for 

providing data services from about 9.6 Kbps to about 153.6 

Kbps. 

In the HDR system, a base station (a part of the access 

network AN) can always transmit signals at its maximum 

transmission power, as virtually no power control is required 

because only one user occupies a single channel at a 

particular time resulting in practically no interference from 

other users. Also, in contrast to an IS-95 system requiring an 

equal data transfer rate for all users, an HDR system need 

not deliver packet data to all users at equal data transfer 

rates. Accordingly, users receiving high strength signals can 

receive services employing high data rates, while users 

receiving low strength signals can be accorded with more 

time slots so that their unequal (i.e., lower) data rate is 

compensated. 

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65 

4 

In conventional IS-95 systems, because various signals (including pilot signals) are simultaneously transmitted to all 

users, interference due to pilot signals and undesirably high 

power consumption are problematic. However, in HDR 

systems, pilot signals can be transmitted at maximum power 

because the so-called “burst' pilot signals are employed. 

Thus, signal strength can be measured more accurately, error 

rates can be reduced, and interference between pilot signals is minimized. Also, as the HDR system is a synchronous 

system, pilot signals in adjacent cells are simultaneously 

transmitted, and interference from pilot signals in adjacent 

cells can also be minimized. 

FIG. 1 shows a portion of a conventional reverse channel 

structure for sending transmission data rate increase infor 

mation from a base station to a mobile. A base station (not 

shown) approximates (or measures) a load on the reverse 

link, and prepares to send to a mobile (not shown) various 

messages indicating whether the reverse link load is large or 

small. A bit repetition means 10 repeats the bits in the 

messages to be sent a certain number of times to improve signal reliability. 

Thereafter, a signal point mapper 11 maps the signal from 

the bit repetition means 10 by, for example, changing all “0” 

bits to “+1 and all “1” bits to “-1 to allow further 

processing. The resulting signal is combined with a so-called 

“Walsh cover signal and transmitted over the Reverse 

Activity (RA) channel to the mobile. 

A conventional mobile receives the messages sent by the 

base station via the RA channel indicating that the current 

reverse link load is too large, and the mobile reduces the 

current packet data rate on the reverse link by one-half (1/2) 

so that the load on the reverse link is decreased. 

SUMMARY OF THE INVENTION 

Agist of the present invention involves the recognition by 

the present inventors of the drawbacks in the previously known art. In particular, previously known techniques (e.g., 

mobile communications systems under the standards of 

IS-95, HDR, IMT-2000, etc.) for controlling data transmis 

sion rates between mobiles and a base station do not 

effectively consider the particular data transmission circum 

stances and channel conditions of each mobile station. 

Previously known HDR systems do not employ effective 

power control techniques, thus there are difficulties in pro 

viding high-speed data transmissions to those mobiles 

located far from the base station requiring signal transmis 

sions at a higher power compared with the signal transmis 

sions for mobiles located in proximity to the base station 

requiring only low level power. 

The previously known HDR system is disadvantageous in 

that, when the base station detects the load on the reverse 

link to be too large and feeds back this information via a 

reverse activity (RA) channel, the reverse link packet data 

rate is unconditionally reduced by one-half for all users 

(mobiles), and thus overall data throughput at each base 

station is undesirably reduced. The previously known art 

ignores the situations that individual mobiles have different 

requirements and should advantageously be controlled indi 

vidually in a dedicated manner. 

Additionally, the previously known HDR system is inef 

ficient because no messages are sent to the mobiles to 

indicate that their packet data rates should be increased 

when the reverse link load is small. 

Furthermore, the previously known art merely considers 

the reverse link load. However, in practical data packet 

transmission applications, the channel or link conditions, 

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US 7,215,653 B2 

5 

Such as signal interference and transmission power require 

ments, and other communications environment factors effect 

data transmissions on the reverse link. 

To address at least the above-identified previously known 

art problems, the present invention utilizes information fed 

back from the forward link for data packet transmission over 

the reverse link upon considering the particular data trans 

mission circumstances and channel conditions of each 

mobile station and accordingly controlling the mobiles in a 

dedicated manner. By doing so, the data transmission rate 

over the reverse link is improved. More specifically, to 

improve reverse link data transmission rates, messages 

informing the mobile station to adjust (increase, decrease or 

maintain) its data transmission rate are sent from the base 

station in accordance with reverse link load information. 

BRIEF DESCRIPTION OF THE DRAWINGS 

FIG. 1 shows a portion of a conventional reverse channel 

structure for sending transmission data rate increase infor 

mation from a base station to a mobile; 

FIG. 2 shows a partial structure of a mobile according to 

an embodiment of the present invention; 

FIG. 3 shows a partial structure of a base station accord 

ing to an embodiment of the present invention; 

FIG. 4 shows the details of certain relative portions of the 

determinator 34 in a base station, a portion of which is 

shown in FIG. 3; 

FIG. 5 is a flow chart showing the main steps involved in 

transmitting transmission data rate adjust information to 

each mobile in a 1xEV-DV or 1xEV-DO system according 

to the present invention; 

FIG. 6 is a flow diagram of the method for controlling the 

data transmission rate in accordance with the present inven 

tion; 

FIG. 7 is a flow diagram of embodiment according to the 

present invention; 

FIG. 8 shows the updating procedure of the BS RCV 

according to the present invention; 

FIG. 9 shows the procedures for generating rate control 

information using the BS RCV values according to the 

present invention; and 

FIG. 10 shows an example of how the reverse link data 

rate is controlled using the BS RCV values according to the 

present invention. 

DETAILED DESCRIPTION OF THE 

PREFERRED EMBODIMENT 

FIG. 2 shows a partial structure of a mobile according to 

an embodiment of the present invention. A mobile 20 

comprises a reception processor 21, a demodulator 22, a 

transmission data rate controller 23, and a transmission 

processor 24. The reception processor 21 processes the 

signals received from a base station via a reception antenna 

A1. The demodulator 22 demodulates the signals processed 

by the reception processor 21. The transmission data rate 

controller 23 controls the transmission data rate based on the 

transmission data rate adjustment information in the signals 

processed by the demodulator 22. The transmission proces 

Sor 24 transmits signals via a transmission antenna A2 to the 

base station in accordance with the control of the transmis 

sion data rate controller 23. 

According to FIG. 2, the mobile according to an embodi 

ment of the present invention can comprise a determining 

means which determines a transmission energy level 

required for transmitting to a base station. Here, the deter 

10 

15 

25 

30 

35 

40 

45 

50 

55 

60 

65 

6 

mining means can comprise the transmission data rate 

controller 23 and the transmission processor 24, in their 

entirety or portions thereof. 

Also, the mobile according to an embodiment of the 

present invention can comprise an adjusting means opera 

tively connected with the determining means, which adjusts 

a data transmission rate based upon a comparison result 

received from the base station in a dedicated manner via a 

common channel, the comparison result being obtained by comparing the transmission energy level and an interference 

level of signals sent to the base station by the mobile 

stations. Here, the adjusting means can comprise the trans 

mission data rate controller 23, and the transmission pro 

cessor 24, in their entirety or portions thereof. 

Furthermore, the mobile according to an embodiment of 

the present invention can comprise a transceiver operatively 

connected with the adjusting means, which transmits packet 

data on the reverse link in accordance with the adjusted data 

transmission rate. Here, the transceiver can comprise the 

reception processor 21, the demodulator 22, the transmission 

processor 24, and antennae A1 and A2, in their entirety or 

portions thereof. 

FIG. 3 shows a partial structure of a base station accord 

ing to an embodiment of the present invention. A base 

station 30 comprises a reception processor 31, an interfer 

ence level detector 32, a comparator 33, a determinator 34, 

and a transmission processor 35. The reception processor 31 

processes (e.g., demodulates) the signals received from 

mobiles (not shown) via a reception antenna A3. The inter 

ference level detector 32 receives the processed signals from 

the reception processor 31 for estimating and/or detecting a 

level of signal interference related to the processed signals. 

As understood by those skilled in the art, there are various 

types of signal interference between mobiles and base 

stations in mobile communications. For example, in the case 

of the reverse link, an important parameter is the rise in the 

level of the total amount of noise over the level of the 

thermal noise at a base station. This parameter is referred to 

as the “rise over thermal (ROT). The rise over thermal 

(ROT) corresponds to the loading of the reverse link. 

Typically, a communications system attempts to maintain 

the ROT near a predetermined value. If the ROT is too great, 

the range of the cell is reduced and the reverse link is less 

stable. A large ROT can also cause Small changes in instan 

taneous loading that result in large excursions in the output 

power of the mobile station. When the ROT is considered to 

be too high (e.g., above a desired threshold level), the data 

transmission rate can be decreased or even interrupted until 

the reverse link is stabilized. In contrast, a low ROT can 

indicate that the reverse link is not heavily loaded, thus 

potentially wasting available capacity. Thus, if the ROT is 

considered to be too low (e.g., below a desired threshold 

level), the data transmission rate can be advantageously 

increased. It will be understood by those skilled in the art 

that methods other than measuring the ROT can be used in 

determining the loading of the reverse link. 

After the interference level detector 32 detects the signal interference, the comparator 33 compares the detected level 

of signal interference with a threshold value in order to 

estimate (determine) the load on the reverse link. The 

determinator 34 determines a transmission data rate adjust information (e.g., increase, decrease or maintain) based on 

the reverse link load determined by the comparator 33, and 

determines a position of each mobile (i.e., a physical loca 

tion of each mobile in the cell/sector served by the base 

station) based on the rate control bit (RCB) position in the 

Case 1:20-cv-22051-JEM Document 1-18 Entered on FLSD Docket 05/15/2020 Page 13 of 20
US 7,215,653 B2 

7 

channel slots. The RCB position in the channel slots allows 

mobiles to be discriminated from one another. 

The transmission processor 35 modulates a transmission 

signal for sending the transmission data rate adjust infor 

mation from the determinator 34 to each mobile, and trans 

mits signals to each mobile via a transmission antenna A4. 

Here, the signals including the RCB information are trans 

mitted to each mobile via a common channel. The common 

channel can be a known channel already used in conven 

tional mobile communications. For example, the so-called 

“RA channel can be employed in the present invention for 

transmitting signals and RCB information to each mobile. 

Alternatively, the signals including the RCB information are 

transmitted to each mobile via a newly established channel 

(Common Reverse Packet Data Control Channel—CRPD 

CCH), not currently existing in conventional mobile com 

munications systems and techniques. Here, various conven 

tional techniques may be employed in establishing a new 

type of channel, with a feature of the present invention being 

the use of rate control bit (RCB) in the frames (16 slots) 

transmitted to the mobiles. 

According to FIG. 3, a base station according to an 

embodiment of the present invention can comprise a deter 

mining means, which determines an interference level of 

signals received from the mobile stations, and determines a 

transmission energy level required for each mobile station. 

Here, the determining means can comprise the interference 

level detector 32 and the comparator 33, in their entirety or 

portions thereof. 

Also, a base station according to an embodiment of the 

present invention can comprise a comparing means opera 

tively connected with the determining means, which com 

pares the interference level with the transmission energy 

level to obtain a comparison result for each mobile station. 

Here, the comparing means can comprise the comparator 33 

and determinator 34, in their entirety or portions thereof. 

Additionally, a base station according to an embodiment 

of the present invention can comprise a transceiver opera 

tively connected with the comparing means, which sends the 

comparison result via a common channel on a forward link 

to each mobile station in a dedicated manner in accordance 

with the comparing, and receives packet data on the reverse 

link in response to the sending. Here, the transceiver can 

comprise a reception processor 31, transmission processor 

35, and antennae A3 and A4, in their entirety or portions 

thereof. 

Accordingly, by using the general features of a mobile 

shown in FIG. 2 and the features of a base station shown in 

FIG. 3, data packets can be transmitted between the mobile 

and base station in accordance with the present invention. A 

more detailed description and explanation of the structural 

aspects and methods involved in the present invention are as 

follows. 

FIG. 4 shows the details of certain relative portions of the 

determinator 34 in the base station shown in FIG. 2. The 

determinator 34 comprises a plurality of repeaters 41, a 

plurality of signal point mappers 42, a plurality of channel 

gain units 43, a pair of multiplexors 44, and a long code 

processor 45 having a long code generator 46, a decimator 

47, and a relative offset calculator 48. 

In the present invention, mobiles can be controlled via the 

so-called “I-channel or “Q-channel or both channels. 

Here, “I” refers to “in-phase' and "Q" refers to “quadra 

ture,” which are known terms in the art of digital signal 

modulation, in particular vector modulation. Vector modu 

lation (of which quadrature amplitude modulation (QAM) is 

a popular type) is at the heart of most digital wireless 

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8 

(mobile) communication systems. QAM packs multiple data 

bits into single symbols, each of which modulates the 

carrier's amplitude and phase. 

Of the reverse link load determined by the comparator 33, 

rate-control bits (e.g., RCBs) for each user (mobiles) 0 

through N are sent to the determinator 34. Here, N denotes 

the number of users being controlled using the I-channel 

and/or Q-channel, which are also referred to as an “I-Arm’ 

and a “Q-Arm.” Based upon the RCBs transmitted to the 

mobiles during one data frame (the frame having 16 slots), 

the base station can control a plurality of mobiles using the 

I-channel, the Q-channel, or both. 

The repeaters 41 of the determinator 34 receive the RCB 

data (including rate-control bits) related to a plurality of 

users (mobiles) 0 through N, and respectively processes 

these data for ultimately generating I-signals (X) and/or 

Q-signals (X). 

For example, 12, 24, 48, 96, 192 or 384 mobiles can be 

controlled by the base station according to the present 

invention. If only the I-channel or the Q-channel is used, 12, 

24, 48, 96 or 192 mobiles can be controlled. If both the 

I-channel and Q-channel are used, 24, 48, 96, 192 or 384 

mobiles can be controlled. When either the I-channel or the 

Q-channel is used to control 12 mobiles, the repeater 41 

repeats the bits in the messages to be sent 16 times to 

improve signal reliability. In this manner, for respectively 

controlling 24, 48, or 96 mobiles, 8, 4, or 2 repetitions are 

performed, respectively. For controlling 192 mobiles, no 

repetitions are made. Namely, instruction signals are sent to 

the mobiles without performing any bit repetitions. In a 

similar manner, when both the I-channel and the Q-channel 

are used, for respectively controlling 24, 48, 96 or 192 

mobiles, 16, 8, 4, or 2 repetitions are performed. For 

controlling 384 mobiles, instruction signals are sent to the 

mobiles without performing any bit repetitions. 

Although a particular number of mobiles capable of being 

controlled have been exemplified above based upon there 

being 16 slots in a frame to be transmitted, those skilled in 

the art would understand that other specific number of 

mobiles could also be handled according to the present invention depending upon the particular frame size and 

number of slots therein. 

Then, the signal point mappers 42 map the signals 

received from the repeaters 41 by, for example, changing all 

“0” bits to “+1, all “1” bits to “-1”, and no symbol bits to 

“0” to allow further processing. 

Here, the signal point mapping techniques can generally 

be performed in a variety of ways, as understood by those 

skilled in the art. However, a preferred method in signal point mapping according to the present invention involves a 

particular technique of processing the RCBs. Namely, based 

upon the transmission data rate adjust information, if the 

current transmission data rate is to be increased, the base 

Station sets the RCB to “INCREASE and if the current 

transmission data rate is to be decreased, the base station sets 

the RCB to “DECREASE Also, if current transmission data 

rate is to be maintained, no RCB information is transmitted 

by the base station to the mobile. 

Also, the number of slots used for processing a symbol 

depends upon the number of users N. For example, if N=12, 

1 symbol per 1 slot is processed. Also, for N=24, 48, 96 or 

192, 1 symbol/2 slots, 1 symbol/4 slots, 1 symbol/8 slots, 

and 1 symbol/16 slots are processed, respectively, as indi 

cated in FIG. 4. 

Thereafter, the channel gain units 43 further process each 

signal received from the signal point mappers 42, respec tively. Namely, channel gain amplification is performed and 

Case 1:20-cv-22051-JEM Document 1-18 Entered on FLSD Docket 05/15/2020 Page 14 of 20
US 7,215,653 B2 

the processed signals are sent to the multiplexers (MUX) 44, 

the features of which are explained further below. Here, the 

channel gain amplifying techniques can generally be per 

formed in a variety of ways, as understood by those skilled 

in the art. 

Additionally, the RCB data related to I-Q signal genera 

tion includes initial offset values (0 to N-1) assigned to each 

user (mobile) and which determine the position of each 

mobile (based on the RCB position in the channel slots). 

Here, the initial offset values are determined (or generated) during a so-called “negotiation’ process between mobiles 

and the base station. Of the initial offset values, “0” indicates 

the first position among the channel slots, while “N-1 

indicates the last position. 

The determinator 34 also includes a long code processor 45 comprising a long code generator 46, a decimator 47 and 

a relative offset calculator 48. The long code processor 45 

receives a long code mask for the common reverse packet 

data control channel (CRPDCCH) and outputs relative offset 

values used for generating an I-signal and a Q-signal. Here, 

for the relative offset values, the RCB positions allocated to 

each mobile are preferably randomized. Namely, the RCBs 

are inserted into different slot positions in each frame. As 

such, the RCB position in the channel slots allows mobiles 

to be discriminated from one another. 

Finally, the multiplexers (MUX) 44 respectively combine 

the initial offset values assigned to each user with the 

relative offset values (generated by the long code processor 

45), and the processed signals from the channel gain units 

43, so that the RCB positions in the channel slots are 

determined. As a result, the multiplexed signals X, and Xo 

for the I-channel, the Q-channel, or both are outputted from 

the determinator 34 for further processing at the transmis 

sion processor 35 and Subsequent transmission to the 

mobiles. 

FIG. 5 is a flow chart showing the principle steps involved 

in transmitting transmission data rate adjust information to 

each mobile in a 1xEV-DV or 1xEV-DO system according 

to an embodiment of the present invention. First, the base 

station detects and determines a level of interference among 

all communication traffic channels (S51). The detected inter 

ference level is compared with a threshold so that the load 

on the reverse link can be approximated (S52, S53). Trans 

mission data rate adjust information is determined by the 

reverse link load and information regarding the distance 

from each mobile to the base station, and as previously explained in view of FIG. 4, the multiplexers 41, 41 

combine the initial offset values (from the I-signals and 

Q-signals) with the relative offset values (from decimating 

the codes from the long code generator 46) so that the RCBs 

positions in the channel slots are determined for discrimi 

nating each mobile from one another (S54). Finally, the 

RCBs are transmitted to the mobiles via a common channel, 

which operate in a dedicated manner (i.e., exclusively) for 

each mobile (S55). 

Upon receiving the RCBs from the base station, the 

mobiles preferably adjust their transmission data rates in 

increments for gradual increasing or decreasing. Then, the 

mobiles may inform the base station of the adjusted trans 

mission data rate which they intend to use by sending to the 

base station a reverse rate indicator (RRI). Thereafter, packet 

data are transmitted to the base station on the reverse link at 

the adjusted data rate. Accordingly, employing the tech 

niques of the present invention can advantageously increase 

data throughput. 

The instructions (based upon RCBs) sent by the base 

station to the mobiles for adjusting (increasing, decreasing 

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35 

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45 

50 

55 

60 

65 

10 

or maintaining) the transmission data rate of a mobile during 

the reverse link will be referred to as “RC instructions.” In 

the present invention, the base station preferably sends RC 

instructions to the mobiles during a single frame, for con 

trolling the transmission date rate of the mobiles during the 

next frame. However, those skilled in the art can understand 

that the sending of RC instructions may extend into a 

Subsequent frame in certain situations. 

FIG. 6 shows a flow diagram of the method for controlling 

the data transmission rate in accordance with the present invention. For controlling a data transmission rate on a 

reverse link in a mobile communications system having a 

plurality of base stations and a plurality of mobile stations, 

a first step of determining an interference level at a base 

station due to signals from the mobile stations served by the 

base station is performed (S60). Also, a step of determining 

a transmission energy level required for each mobile station 

is performed (S62). Next, the interference level is compared with the transmission energy level to obtain a comparison 

result for each mobile station (S64). 

Thereafter, the comparison result is transmitted by the 

base station to the mobile via a common channel on a 

forward link in a dedicated manner (S66). Here, the base 

station transmits respective comparison results to each 

mobile in a dedicated manner. In other words, the base 

station sends a particular comparison result to a particular 

mobile (having a particular interference level and required 

transmission energy level previously determined) so that 

each mobile is individually controlled to have an appropriate 

data transmission rate. 

Subsequently, each mobile adjusts its current data trans 

mission rate based upon the comparison result sent from the 

base station via a common channel on a forward link in a 

dedicated manner (S68). Finally, packet data are transmitted on the reverse link from a mobile to the base station in 

accordance with the adjusted data transmission rate (S69). 

In other words, a method for controlling a data transmis 

sion rate on a reverse link according to the present invention 

can comprise the steps of determining an interference level 

at a base station due to signals from the mobile stations 

served by the base station; determining a transmission 

energy level required for each mobile station; comparing the 

interference level with the transmission energy level to 

obtain a comparison result for each mobile station; and 

adjusting a data transmission rate for each mobile station 

based upon the comparison result sent via a common chan 

nel on a forward link to each mobile station in a dedicated 

a. 

Also, a method for controlling a data transmission rate on 

a reverse link according to the present invention can com 

prise the steps of determining an interference level of signals 

received from the mobile stations; determining a transmis 

sion energy level required for each mobile station; compar 

ing the interference level with the transmission energy level 

to obtain a comparison result for each mobile station; and 

sending the comparison result via a common channel on a 

forward link to each mobile station in a dedicated manner in 

accordance with the comparing. Additionally, a method for controlling a data transmission 

rate on a reverse link according to the present invention can 

comprise the steps of determining a transmission energy 

level required for transmitting to the base station; adjusting 

a data transmission rate based upon a comparison result 

received from the base station in a dedicated manner via a 

common channel, the comparison result being obtained by comparing the transmission energy level and an interference 

level of signals sent to the base station by the mobile 

Case 1:20-cv-22051-JEM Document 1-18 Entered on FLSD Docket 05/15/2020 Page 15 of 20
US 7,215,653 B2 

11 

stations; and transmitting packet data on the reverse link in 

accordance with the adjusting. 

The above-described techniques of employing RCB 

according to an embodiment of the present invention 

improve the conventional techniques (e.g., conventional 

communications systems under the standards of IS-95, 

HDR, IMT-2000, etc.) for controlling transmission data rates 

between mobiles and a base station. However, the present inventors recognized that additional improvements are also 

possible. 

For example, the particular communication conditions of 

each mobile may be further considered in addition to the 

overall signal interference at the base station (including 

ROT parameters) described previously hereinabove. By 

considering the factors at each mobile, different mobiles can 

receive different instructions to adjust their respective trans 

mission data rates in a different manner, instead of all 

mobiles receiving the same instruction to increase or 

decrease their transmission data rates by an equal amount. 

In conventional techniques, each mobile performs an 

internal test upon receiving a transmission data rate adjust 

instruction (an RA instruction) from its base station, instead 

of immediately adjusting its current transmission data rate. 

In other words, each mobile further considers its own 

communications conditions prior to adjusting its transmis 

sion data rate. 

The internal test conducted by the mobile involves the 

determination of the probability that the data transmission 

rate in the next frame will likely increase or decrease. 

Namely, if the current data transmission rate is relatively low 

for the current frame, there is a relatively high probability 

that the data transmission rate should be increased in the 

next frame, and there is a relatively low probability that the 

data transmission rate should be decreased in the next frame. 

For example, Suppose that a communications system can 

transmit data at five different rates: 9,600 bps; 19.200 bps; 38.400 bps; 76,800 bps; and 153,600 bps. Assuming that a 

first mobile (A) is transmitting data at 19,200 bps during the 

current frame, while a second mobile (B) is transmitting data 

at 76,800 bps in the current frame. Then, if the base station 

sends to the mobiles that it is serving, an instruction to 

increase the current data transmission rate, mobile A has a 

greater probability of operating at a higher data transmission 

rate compared to mobile B. In contrast, if the base station 

sends to the mobiles that it is serving, an instruction to 

decrease the current data transmission rate, mobile B has a 

greater probability of operating at a lower data transmission 

rate compared to mobile A. 

In other words, a method for controlling a data transmis 

sion rate on a reverse link according to the present invention 

can comprise the steps of detecting a total interference 

amount received by a base station; determining a transmis 

sion energy level required by a mobile station based upon a 

cell interference probability of each mobile station; receiv 

ing transmittable data rate information of each mobile 

station; and generating data rate control information in 

accordance with the total interference amount, the transmis 

sion energy level, and the data rate information for control 

ling a data transmission rate on a reverse link. 

The present invention considers the channel condition or 

state for each mobile, the valid data rate for transmitting 

within a frame, and the signal interference at the base 

station, such that the base station individually controls the reverse link data rate for each mobile in a dedicated manner. 

To achieve this control, various parameters for the base 

station and mobiles can be used. These parameters are 

defined as follows. 

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12 

1) Mobile Station Priority (MS PRI) 

MS PRI is a parameter used for determining a probability 

of cell interference of each mobile, and is obtained by using the following equation (1): 

C f3 (1) MS PRI = - - - as ; Ali Ali 

X ai - a 

This parameter can be calculated by the base station itself or 

by the mobile, which informs the base station of the 

MS PRI value in a periodic manner or whenever the chan 

nel environment of the mobile changes. 

In equation (1), C, denotes the reverse link channel gain 

between the mobile and the i-th base station, while C, denotes the reverse link channel gain between the mobile 

and the j-th base station which has the largest channel gain 

of all base stations. Also, B, denotes the forward link channel 

gain between the mobile and the i-th base station, while B, denotes the forward link channel gain between the mobile 

and the j-th base station which has the largest channel gain 

of all base stations. 

When fading is not considered (i.e., ignored), the channel 

gain of the forward link and the channel gain of the reverse 

link can be considered to be the equivalent. Thus, the 

approximation: 

f3; Ali Ali --- 

X ai - a 

of equation (1) is satisfied. 

Also, assuming that the total transmission power of all 

base stations are approximately the same, when the total 

transmission power of the base station is multiplied to the 

channel gain (i.e., multiply the total transmission power of 

the base station by B), the resulting value is equivalent to the 

total signal power received by one mobile from the i-th base 

station (i.e., Ior). Thus, the approximation: 

max Ior, 

MS PRI as f lo- max Ior, 

of equation (1) is satisfied, and the MS PRI value can be 

determined. 

In equation (1), Io denotes the total sum of the signal 

power from all base stations received by the mobile (i.e., 

sum of Ior received from all base stations), and max_Ior, denotes the signal power received from the j-th base station 

which has the strongest reception signal power of all base 

stations. 

The MS PRI value, indicates in an inversely proportional 

manner, how a particular mobile, on average, causes cell 

interference to other cells. A large MS PRI value means that 

the probability of causing cell interference is low, while a 

small MS PRI value means that the probability of causing 

cell interference is high. In other words, a large MS PRI 

value indirectly indicates a high probability that the mobile 

is located near a base station or that the mobile is located in 

a place where the channel state is satisfactory, while a small 

MS PRI value denotes the opposite. 

Case 1:20-cv-22051-JEM Document 1-18 Entered on FLSD Docket 05/15/2020 Page 16 of 20
US 7,215,653 B2 

13 

The MS PRI value can be calculated in at least the 

following three different methods. 

First, the mobile calculates the MS PRI value using the Io 

value detected from the total sum of signal power received 

from all base stations, and the max Ior value of the base 

stations having the greatest reception signal power, and 

thereafter the MS PRI value is directly transmitted to the 

base station. 

Second, the mobile sends to the appropriate base station, 

the Ec/Io value of the pilot signal (Ec) power received from 

each base station using the pilot signal measurement mes 

sage (PSMM) reported to the base station. Then, the base 

station receiving the Ec/Io value uses this to calculate the 

MS PRI value. 

Third, when there exists a reverse link channel (such as 

the data rate control (DRC) channel in 1xEV-DO systems) 

for informing the channel state of the forward link, the base 

station uses the forward link channel state value (such as the 

Ec/Nt of the pilot signal (Ec)) transmitted via this channel to 

calculate the MS PRI value. 

2) Mobile station reverse control value (MS RCV) 

The MS RCV value is a parameter used for determining 

the transmission energy value necessary for each mobile.). 

First, a function f(x) is defined, a calculation using the 

following equation (2) is performed. 

MS RCV f(Current Assigned Data Rate) dB or MS PRIIdB) (2) 

Here, the MS RCV value may be indicated in units of dB. 

Also, “Current Assigned Data Rate denotes the data rate 

being used in the current transmission frame, while f(x) is 

a function related to the reception energy necessary for 

normally receiving data from a base station at a data rate of 

x. For example, if the “Current Assigned Data Rate' is 

9600, we get a function f(9600)=4dB, which calculates in 

advance, a reception energy level for each data rate. 

Thus, the MS RCV value applies cell interference prob abilities to the reception energy necessary for each mobile. 

Thus, the present invention employing the MS RCV value 

can minimize the occurrence of cell interference by using a 

relatively low transmission energy level (transmit power) satisfy the reception energy level (reception power) 

requested by the base station, for those mobiles that are close 

to the base station or having a strong channel link. 

In general, as the data rate increases, the reception energy 

required for each mobile also increases. Thus, as the “Cur 

rent Assigned Data Rate' is higher, the MS RCV value 

increases. 

In equation (2), the MS PRI value in the term 

“O MS PRI denotes the probability of causing interfer 

ence to other cells. If the MS PRI value is small (i.e., when 

there is a high probability of causing interference to other 

cells), the MS RCV value becomes large. 

Also, the value “C.”, which can be adjusted to control how 

the MS PRI effects the MS RCV, is a variable that controls 

the “fairness' between users (mobiles). The base station 

adjusts the a value so that all mobiles are guaranteed to have 

an appropriate data rate. For example, when C. 0, the 

channel conditions for the mobile are not considered and the 

degree of fairness between the users (mobiles) is at a 

maximum. In contrast, as the a value increases, the channel 

conditions of each mobile have more effect on the MS RCV 

value. 

In Summary, as the data rate of the current transmission is 

higher, and as the MS-PRI value is lower (i.e., as the 

probability of causing other cell interference is greater), the 

5 

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35 

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45 

50 

55 

60 

65 

14 

MS RCV value increases. The base station calculates and 

manages the MS RCV value for each active mobile. 

3) Mobile Station Rate Increase Available Bit (MS IAB) 

The MS IAB value is a parameter to provide data rate 

information for valid data that can be transmitted in the next 

frame by the mobile. The MS IAB value has two states, “increase' and “unchanged, based on the following condi 

tions. 

If all the following conditions are met, the MS IAB value 

is set as “increase,” while if any one of these conditions is 

not met, the value is set as “unchanged.” 

I. When transmission power margin (i.e., remaining trans 

mission power) is above a certain level; 

II. When the number of bits in the transmission buffer is 

above a certain level; and 

III. When the data rate of the current transfer (i.e., 

Current Assigned Data Rate) is below a maximum data 

rate (i.e., MAX. Data Rate) set by the system. 

As shown in FIG. 7, which is a flow diagram of embodi 

ment according to the present invention, the base station 

uses the above-identified parameters (i.e., MA PRI. 

MS RCV, and MS IAB) for controlling the data transmis 

sion rate of a mobile. 

The base station receives the MS PRI value reported 

from the mobile in a periodic manner or whenever the 

channel conditions of the mobile change, or directly calcu 

lates the MS PRI value for updating thereof. Here, the 

MS PRI value is initially set at 0 and updated thereafter 

(S70). 

The base station uses the thusly obtained MS PRI value 

and the data rate at which the mobile is transmitting, i.e., the 

“Current Assigned Data Rate, for calculating and manag 

ing MS RCV values for those mobiles that are in an active 

state with regard to the base station (S71). 

Also, the base station detects the total interference (e.g., 

the rise over thermal (ROT) value) based on the total energy 

of signals received at the base station (S72). Thereafter, each 

mobile transmits the MS IAB value to the base station in 

every frame (S73). 

The base station uses the MS RCV and MS IAB values 

to generate a rate control bit (RCB) for controlling the data 

rate of each mobile (S74), and the RCB is transmitted to 

each mobile (S75). Here, the RCB can include three types of 

commands; an increase command for increasing the data 

rate of the mobile, a decrease command for decreasing the 

data rate, and a command for not changing the data rate. 

If the ROT detected by the base station is deemed to be 

satisfactory (e.g., ROT-ROT TH1, where ROT TH1 is a 

first threshold value), the MS RCV value is accordingly 

below a threshold value (RCV TH), and of the mobiles 

having their MS IAB values set as “increase, the RCB 

values for certain mobiles are set as “increase' while the 

RCB values for the remaining mobiles are set as 

“unchanged.” 

However, if it is determined that the ROT detected by the 

base station is maintained with a range 

(ROT TH1-ROT TH2) set by the system, the RCB values 

for all mobiles are set to “unchanged.” 

If the ROT detected by the base station is deemed to be 

unsatisfactory (e.g., ROTs-ROT TH2, where ROT TH2 is a 

second threshold value), for those mobiles having a 

MS RCV value exceeding the RCV-TH value, their RCB 

values are set as “decrease' while the RCB values for the 

remaining mobiles are set to “unchanged.” 

In the above method, the particular number of mobiles 

having their RCB values set as “increase,” “decrease,” or 

Case 1:20-cv-22051-JEM Document 1-18 Entered on FLSD Docket 05/15/2020 Page 17 of 20
US 7,215,653 B2 

15 

“unchanged depends on various factors such as the actual 

implementation environment, system performance, capacity, 

operation purpose, and the like. In a particular embodiment, 

the following algorithm is presented to show how the above 

features may be applied an implemented. 

First, a parameter BS RCV (Base Station Rate Control 

Value) is defined to determine the total number of mobiles. 

Here, for the BS RCV, the lowest MS RCV value of the 

MS RCV values (calculated at a base station or reported 

from a mobile) at a data rate of 9600 bps is set as its initial 

value. Thus, the BS RCV is defined to limit the selective 

range of the MS RCV such that only those mobiles having 

an MS RCV value being above or below a certain level 

receive RCB increase or decrease data rate control informa 

tion. 

FIG. 8 shows the updating procedure of the BS RCV 

according to the present invention. The base station deter 

mines the total interference amount (i.e., ROT) received by the base station in the unit of time having a particular period. 

The base station then uses the detected ROT value to update 

the BS RCV. If the detected ROT value is below ROT TH1, 

BS RCV increases by A. and if the ROT value is below 

ROT TH2, BS RCV decreases by A. However, if the ROT 

is maintained within a range between ROT TH1 and 

ROT TH2, the BS RCV value is maintained at its previous 

value. 

FIG. 9 shows the procedures for generating rate control 

information using the BS RCV values according to the 

present invention. First, the base station updates the 

BS RCV value using the detected ROT value as shown in 

FIG 8. 

Then, the base station generates an RCB for each mobiles 

based on the following conditions using the MS RCV value, 

the BS RCV value, and the MS IAB value received from 

the respective mobile. If (MS RCV+)-BS RCV, and 

MS IAB="increase' are satisfied, the RCB is set as 

“increase.” But, if MS RCV>BS RCV, then RCB is set as 

“decrease.” However, if (MS RCV+) <BS RCV and 

MS IAB “increase,” or if MS RCV BS RCV (MS RCV+ 

w), the RCB is set as “unchanged.” As such, the present invention employs the “a value to more appropriately 

control the RCB value setting allocation to better reflect the 

communications environment. 

FIG. 10 shows an example of how the reverse link data 

rate is controlled using the BS RCV values according to the 

present invention. Namely, the steps for controlling the data 

rate of a mobile by the base station in an exclusive or 

dedicated manner are shown. 

The base station updates the MS PRI value by receiving 

a MS PRI value from the mobile reported therefrom peri odically, or whenever the channel conditions of the mobile 

change, or by directly calculating a MS PRI value at the 

base station itself. The MS PRI value is initially set as 0 and 

updated thereafter (S100). 

The base station uses the MS PRI value and the data rate 

used by the mobile for transmission (i.e., the “Current As 

signed Data Rate') to calculate and manage the MS RCV 

values of all mobiles being in active state with respect to the 

base station (S102). 

The base station determines the total energy of the signals 

received thereof (i.e. the total interference amount, such as 

ROT) for each time interval having a certain period (S104). 

Then, the base station updates the BS RCV values using 

the method shown previously in FIG. 8 (S106). Thereafter, 

each mobile, for each frame, transmits the MS IAB value to 

the base station (S108). 

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55 

60 

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16 

The base station then generates rate control bit (RCB) for 

controlling the data rate of each mobile using the MS RCV. 

MS IAB, and BS RCV values (S110), and the RCB values 

are transmitted to each mobile (S112). 

A respective mobile receives RCB values from all active 

base stations (S114), and generates a Combined RCB from 

the received RCB values for controlling the data rate of the 

next frame accordingly (S116). A method for combining the 

RCB values received from all active base stations is as 

follows: 

If all received RCB values are set as “increase, the 

combined RCB is set as “increase.” If any one of the RCB 

values is set as “decrease, the combined RCB is set as 

“decrease.” In all other situations, the combined RCB is set 

as “unchanged.” 

In other words, a method for controlling a data transmis 

sion rate on a reverse link according to the present invention 

can comprise the steps of determining a channel condition 

value of each mobile station by a pilot channel average 

power level and a data transmission rate; comparing the 

channel condition value with a transmission threshold of a 

base station calculated by an interference at the base station; 

and adjusting a data transmission rate for each mobile 

station based upon the comparison result sent via a channel on a forward link to each mobile station in a dedicated 

a. 

Additionally, a method for controlling a data transmission 

rate on a reverse link according to the present invention can 

comprise the steps of determining a total interference level 

of signals received from one or more mobile stations; 

determining a data transmission control threshold value 

according to the total interference level; determining a 

transmission condition value by receiving a reverse link data 

transmission rate and a transmitted pilot signal strength from 

the one or more mobile stations; generating reverse link data 

transmission rate commands by comparing the transmission 

condition value with the data transmission control threshold 

value; and transmitting data to each mobile station in 

accordance with the generated reverse link data transmission 

rate commands. 

Furthermore, a method for controlling a data transmission 

rate on a reverse link according to the present invention can 

comprise the steps of determining a total interference level 

of signals received at a base station; receiving a transmission 

pilot signal strength and a reverse link data transmission rate 

from a mobile station; and generating and sending to the 

mobile station, a reverse link data transmission rate com 

mand using the total interference level, the transmission 

pilot signal strength, and the a reverse link data transmission 

rate. 

As described above, in accordance with the present inven 

tion, the data rate control information is generated by considering not only the total interference amount received 

by the base station, but also the signal reception conditions 

at each mobile. Thus, exclusive or dedicated data rate 

control for each mobile is possible. Accordingly, improved 

data transmissions being more appropriate to the channel 

conditions of each mobile is achieved, and data throughput is significantly gained. Also, base station management is 

advantageously improved, as the base station can accurately 

control the loading on the reverse link. 

The present invention has been described above with 

respect to variations in data transmission techniques 

between a base station and mobile station served by the base 

station, focusing on transmissions on the reverse link in a 

next generation CDMA system. However, it will be under 

stood that the invention can be advantageously applied to 

Case 1:20-cv-22051-JEM Document 1-18 Entered on FLSD Docket 05/15/2020 Page 18 of 20
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other situations including transmissions on other types of 

channels and other mobile communication systems being developed for handling data packet transmissions. 

This specification describes various illustrative embodi 

ments of a method and device of the present invention. The 

Scope of the claims is intended to cover various modifica 

tions and equivalent arrangements of the illustrative embodi 

ments disclosed in the specification. Therefore, the follow 

ing claims should be accorded the reasonably broadest 

interpretation to cover modifications, equivalent structures, 

and features that are consistent with the spirit and scope of 

the invention disclosed herein. 

What is claimed is: 

1. A method for controlling a data transmission rate on a 

reverse link in a mobile communications system including a 

plurality of base stations and a plurality of mobile stations, 

the method comprising: 

determining at a base station a data rate control command 

for controlling a transmission data rate of each mobile 

station to consider a channel condition or state of each 

mobile station; 

sending each data rate control command via a forward common channel in a dedicated manner to the mobile 

stations, the data rate control command being formed 

of at least one rate control bit that is signal point 

mapped to at least one symbol of +1, -1, and 0 to 

indicate whether the mobile station should increase, 

decrease, or maintain its current data transmission rate; 

and 

allowing each mobile station to adjust or maintain its data 

transmission rate based on the data rate control com 

mand, wherein a bit received from the mobile station on 

a reverse packet data control channel indicates whether 

the mobile station has enough power and data to 

increase its data transmission rate on a reverse packet 

data channel. 

2. The method of claim 1, wherein determining the data 

rate control command is based on an interference level and 

a transmission condition of each mobile station. 

3. The method of claim 2, wherein the interference level 

is determined based on the signals received from each 

mobile station. 

4. The method of claim 2, wherein the transmission 

condition is based on a currently assigned data transmission 

rate. 

5. The method of claim 1, wherein determining the data 

rate control command is based on a status of each mobile 

station. 

6. The method of claim 1, wherein if a current data 

transmission rate of a particular mobile station is to be 

maintained, the rate control bit for the particular mobile 

station is mapped to a symbol of 0. 

7. The method of claim 1, wherein the data rate control 

command is inserted into certain bit positions in a channel 

slot of the common channel. 

8. The method of claim 7, wherein the certain bit position 

is determined based on a relative offset of a first bit position 

of the channel slot. 

9. The method of claim 1, wherein determining the data 

rate control command is based on an interference level 

related to a rise over thermal (ROT) parameter. 

10. The method of claim 1, wherein determining the data 

rate control command further includes determining a trans 

mission condition of each mobile station based upon a cell 

interference probability of each mobile station. 

5 

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30 

35 

40 

45 

50 

55 

60 

65 

18 

11. The method of claim 10, wherein the base station 

receives the cell interference probability reported from each 

mobile station or calculates the cell interference probability 

by itself. 

12. The method of claim 1, wherein determining the data 

rate control command further includes calculating a trans 

mission condition of each mobile station using the cell 

interference probability applied to the energy required for a 

data rate for a current transmission frame for each mobile 

station. 

13. The method of claim 1, wherein each mobile station 

transmits to the base station data rate information indicating 

whether the mobile station can transmit data in a next frame 

by increasing its data rate, and the data rate information is 

used when determining the data rate control command 

indicating how a current data transmission rate of a respec tive mobile station is to be adjusted. 

14. The method of claim 13, wherein the data rate 

information is set as “increase' if a remaining transmission 

power of each mobile station is above a threshold and if the 

data rate of a current transmission is below a maximum data 

rate; otherwise, the data rate information is set as 

“unchanged’. 

15. The method of claim 1, wherein the data rate control 

command is determined based on data rate information 

indicating whether the mobile station can transmit in a next 

frame by increasing its data rate. 

16. The method of claim 15, wherein the data rate control 

command is set as “increase' when a data rate information 

is set as “increase'. 

17. The method of claim 13, wherein the data rate 

information is set as “increase' or “unchanged” based on at 

least one of a remaining power, a current transmission rate, 

and a number of bits within a transmission buffer of each 

mobile station. 

18. The method of claim 1, wherein the mobile station 

uses a bit that is sent on a reverse packet data control channel 

to indicate whether it has enough power and data to increase 

its data transmission rate on a reverse packet data channel. 

19. The method of claim 18, wherein the bit is set as “1” 

if the mobile station has sufficient data and power headroom 

to transmit at a rate corresponding to a traffic-to-pilot ratio 

that is greater than a current authorized traffic-to-power 

ratio; otherwise, the bit is set as “0”. 

20. The method of claim 1, wherein a data rate control 

command is generated in accordance with an interference 

level, a transmission energy level, and the data rate infor 

mation. 

21. The method of claim 1, wherein the determining at the 

base station comprises: 

obtaining a total interference level of signals received 

from mobile stations served by the base station, 

obtaining a data transmission control threshold value 

according to the total interference level, 

obtaining a transmission condition value using a data 

transmission rate used by the mobile station for trans 

mission and a pilot signal power value reported from 

the mobile stations, and 

generating a rate control command by comparing the 

transmission condition value with the data transmission 

control threshold value. 

22. The method of claim 21, wherein the data transmis 

sion control threshold value is either maintained if the total 

interference level is within a fixed range, or the data trans 

mission threshold is increased if the total interference level 

Case 1:20-cv-22051-JEM Document 1-18 Entered on FLSD Docket 05/15/2020 Page 19 of 20
US 7,215,653 B2 

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is less than the fixed range, or the data transmission thresh 

old is decreased if the total interference level is greater than 

the fixed range. 

23. The method of claim 21, wherein during the compari 

Son of the transmission condition value with the data trans 

mission control threshold value, 

a data rate control parameter is set as “decrease' if the 

transmission condition value is greater than the data 

transmission control threshold value, 

the data rate control parameter is set as “increase if the 

transmission condition value is Smaller than twice the 

data transmission control threshold value, and 

otherwise the data rate control parameter is set as “main 

tain'. 

24. A base station apparatus for controlling a data trans 

mission rate on a reverse link in a mobile communications 

system including a plurality of mobile stations, the apparatus comprising: 

determining means adapted to determine a data rate 

control command for controlling a transmission data 

rate of each mobile station to consider a channel 

condition or state of each mobile station; and 

a transceiver connected with the determining means 

adapted to send each data rate control command via a 

forward common channel in a dedicated manner to the 

mobile stations, 

wherein the data rate control command being formed of at 

least one rate control bit that is signal point mapped to 

at least one symbol of +1, -1, and 0 to indicate whether 

the mobile station should increase, decrease, or main 

tain its current data transmission rate, wherein the 

transceiver receives a bit from the mobile station on a 

reverse packet data control channel indicating whether 

the mobile station has enough power and data to 

increase its data transmission rate on a reverse packet 

data channel. 

25. The apparatus of claim 24, wherein the determining 

means is adapted to determine the data rate control com 

mand based on an interference level based on signals received from each mobile station and a transmission con 

dition of each mobile station. 

26. The apparatus of claim 24, wherein the data rate 

control command is based on a status of each mobile station. 

27. The apparatus of claim 24, wherein if the current data 

transmission rate of a particular mobile station is to be 

maintained, then the rate control bit for the particular mobile 

station is mapped to a symbol of 0. 

28. The apparatus of claim 24, further comprising means 

adapted to map the data rate control command to at least one 

symbol of +1, -1, and 0. 

29. The apparatus of claim 24, further comprising means 

adapted to insert the data rate control command into certain 

bit positions in a channel slot of the common channel. 

30. The apparatus of claim 29, wherein the inserting 

means is adapted to determine the certain bit position based 

on a relative offset of a first bit position of the channel slot. 

31. The apparatus of claim 24, wherein the determining 

means is adapted to determine the data rate control com 

mand based on data rate information indicating whether the 

mobile station can transmit data in a next frame by increas 

ing its data rate. 

32. The apparatus of claim 24, wherein the determining 

means is adapted to determine an interference level based on 

a rise over thermal (ROT) parameter. 

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60 

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33. The apparatus of claim 24, wherein the determining 

means is adapted to determine a transmission condition 

based on a currently assigned data transmission rate of each 

mobile station. 

34. A mobile station apparatus for use in a mobile 

communications system for controlling a data transmission 

rate on a reverse link, the apparatus comprising: 

receiving means adapted to receive a data rate control 

command of a base station on a forward link common 

channel in a dedicated manner, the data rate control 

command being formed of at least one rate control bit 

that is signal point mapped to at least one symbol of +1, 

-1, and 0 to indicate whether the mobile station should 

increase, decrease, or maintain its current data trans 

mission rate; and 

control means connected with the receiving means 

adapted to control the data transmission rate based on 

the data rate control command, wherein a bit is sent on 

a reverse packet data control channel to indicate 

whether the mobile station has enough power and data 

to increase its data transmission rate on a reverse packet 

data channel. 

35. The apparatus of claim 34, wherein the control means 

is adapted to determine data rate information as “increase' 

or “unchanged to indicate how the mobile station should 

transmit data in a next frame to the base station. 

36. The apparatus of claim 35, wherein the control means 

is adapted to determine the data rate information based on at 

least one of a remaining power, a current transmission data 

rate, and a number of bits within a transmission buffer of 

each mobile station. 

37. A method of controlling a data transmission rate on a 

reverse link received by a mobile station apparatus for use 

in a mobile communications system, the method compris ing: 

receiving a data rate control command of a base station on 

a forward link common channel in a dedicated manner, 

the data rate control command being formed of a least 

one rate control bit that is signal point mapped to at 

least one symbol of +1, -1, and 0 to indicate whether 

the mobile station should increase, decrease, or main 

tain its current data transmission rate; and 

controlling the data transmission rate based on the data 

rate control command rate, wherein a bit is sent on a 

reverse packet data control channel to indicate whether 

the mobile station has enough power and data to 

increase its data transmission rate on a reverse packet 

data channel. 

38. The method of claim 37, further comprising deter 

mining the data rate information as “increase' or 

unchanged to indicate how the mobile station should trans 

mit valid data in the next frame to the base station. 

39. The method of claim 38, wherein determining the data 

rate information is based on at least one of a remaining 

power, a current tranmission data rate, and a number of bits 

within a transmission buffer of each mobile station. 

40. The method of claim 37, wherein the data rate 

information is set as “increase' if a remaining transmission 

power of the mobile station is above a threshold and if the 

data rate of a current transmission is below a maximum data 

rate; otherwise, the data rate information is set as 

“unchanged’. 

Case 1:20-cv-22051-JEM Document 1-18 Entered on FLSD Docket 05/15/2020 Page 20 of 20