SECTION 3\
BPL RELATED STUDIES AND REGULATIONS

**3.1 INTRODUCTION**

This section describes regulations applicable to BPL systems and studies
conducted by various parties to investigate the characteristics of BPL
emissions. The regulations include both the established and proposed
radiation limits applicable to BPL systems.

**3.2 REGULATIONS**

**3.2.1 Part 15 of the Commission\'s Rules**

Appendix A of this report delineates key field strength and compliance
measurement provisions of Part 15 applicable to BPL systems. The Part 15
field strength limits are shown in Table 3-1, below. BPL systems fall
under the Part 15 definition of carrier current systems.[^1] BPL systems
are designed to transmit RF energy over the power line wiring by
conduction; therefore, these systems are treated as unintentional
radiators and the restricted bands of operation defined in 47 C.F.R.
§15.205 do not apply.

Although Part 15 emission limits are intended to limit the risk of
harmful interference to licensed services, compliance measurement
procedures are equally important to the risk of interference because
measurement uncertainty may ultimately result in BPL operation at field
strength levels that are significantly higher or lower than the limits.

**Table 3-1: FCC Part 15 Radiated Emission Limits Relevant to BPL**

+-----------+--------+--------+----------+----------+-------+------+
| **Usage** | *      | *      | **Mea    | **Mea    | **    | **   |
|           | *Frequ | *Field | surement | surement | Detec | Sour |
|           | ency** | Stre   | Di       | Ban      | tor** | ce** |
|           |        | ngth** | stance** | dwidth** |       |      |
|           | **(    |        |          |          |       |      |
|           | MHz)** | **     | **(m     | *        |       |      |
|           |        | (µV/me | eters)** | *(kHz)** |       |      |
|           |        | ter)** |          |          |       |      |
+-----------+--------+--------+----------+----------+-------+------+
| Carrier   | 1.70   | 30     | 30       | 9        | quasi | 15   |
| Current   | 5-30.0 |        |          |          | -peak | .209 |
| Systems   |        |        |          |          |       |      |
+-----------+--------+--------+----------+----------+-------+------+
| Class A,  | 30-88  | 90     | 10       | 120      | quasi | 15   |
| in        |        |        |          |          | -peak | .109 |
| co        |        |        |          |          |       |      |
| mmercial, |        |        |          |          |       |      |
| business, |        |        |          |          |       |      |
| and       |        |        |          |          |       |      |
| i         |        |        |          |          |       |      |
| ndustrial |        |        |          |          |       |      |
| areas     |        |        |          |          |       |      |
+-----------+--------+--------+----------+----------+-------+------+
| Class B,  | 30-88  | 100    | 3        | 120      | quasi | 15   |
| marketed  |        |        |          |          | -peak | .109 |
| for use   |        |        |          |          |       |      |
| in        |        |        |          |          |       |      |
| re        |        |        |          |          |       |      |
| sidential |        |        |          |          |       |      |
| areas     |        |        |          |          |       |      |
+-----------+--------+--------+----------+----------+-------+------+

### 3.2.2 Foreign Regulations

Some administrations have established rules or regulations for BPL
implementation or have deferred BPL implementation pending the results
of on-going studies. BPL has been successfully implemented in some
countries, while other administrations have postponed BPL implementation
while further interference studies are being conducted. Still others
have implemented BPL, experienced interference problems, and then
prohibited BPL operation at least for the time being. Regionally,
emission rules have been proposed for evaluation. Some of these are
presented here. Note that information collected here is not
comprehensive and may not be current in light of the rapid pace of BPL
studies and development. In the summaries presented in this section, the
acronyms BPL (for Broadband on Power Line), PLC (for Power Line
Communications), and PLT (for Power Line Telecommunications or
Technologies) will be used in accordance with each original report.

#### 3.2.2.1 Administrative Rulings on BPL

As summarized in Table 3-2, several administrations reportedly have
already established rules applicable to BPL implementations.

**Table 3-2: Countries and Their Rulings on BPL Implementations**

+-----------+--------------------------------------+-------------------+
| **        | **Ruling or Ruling Rationale**       | **Source of       |
| Country** |                                      | Information**     |
+-----------+--------------------------------------+-------------------+
| Australia | ACA has no mandatory standards for   | http://www        |
|           | BPL equipment for frequencies above  | .aca.gov.au/consu |
|           | 525 kHz.                             | mer_info/fact_she |
|           |                                      | ets/industry_fact |
|           |                                      | _sheets/fsi23.pdf |
+-----------+--------------------------------------+-------------------+
| Austria   | The Ministry of Traffic has          | ht                |
|           | terminated pilot projects on PLC. It | tp://futurezone.o |
|           | concluded that the interference      | rf.at/futurezone. |
|           | caused by PLC to communications in   | orf?read=detail&i |
|           | the frequency range 2 - 30 MHz could | d=205693&tmp=4659 |
|           | not be reduced to acceptable levels. |                   |
+-----------+--------------------------------------+-------------------+
| Finland   | FICORA Annual Report 2001: From      | http:/            |
|           | measurement results, it decided that | /www.ficora.fi/20 |
|           | PLC technology can be accommodated   | 01/VV_vsk2001.pdf |
|           | only after interference and security |                   |
|           | problems have been solved and when   |                   |
|           | the technology complies with         |                   |
|           | official requirements. Favors        |                   |
|           | compliance with NB30 until a         |                   |
|           | pan-European norm is specified.      |                   |
+-----------+--------------------------------------+-------------------+
| Germany   | NB30 (see Table 3-3)                 | <http://w         |
|           |                                      | ww.darc.de/refera |
|           |                                      | te/emv/plc/c3.4-r |
|           |                                      | ev1-PLC5RPRT.pdf> |
+-----------+--------------------------------------+-------------------+
| Japan     | The MPHPT of Japan has determined    | http://www.soumu  |
|           | that at this stage, increasing the   | .go.jp/joho_tsusi |
|           | bandwidth to be used for power line  | n/eng/Releases/Te |
|           | communications would be difficult.   | lecommunications/ |
|           | Proposed feasibility tests promoting | news020809_3.html |
|           | modem research and development.      |                   |
+-----------+--------------------------------------+-------------------+
| U.K.      | No official position yet for the     | <http://ww        |
|           | range 1.6 MHz to 30 MHz.             | w.radio.gov.uk/pu |
|           |                                      | blication/mpt/mpt |
|           |                                      | _pdf/mpt1570.pdf> |
+-----------+--------------------------------------+-------------------+
| ACA:      |                                      |                   |
| A         |                                      |                   |
| ustralian |                                      |                   |
| Commu     |                                      |                   |
| nications |                                      |                   |
| Authority |                                      |                   |
|           |                                      |                   |
| BBC:      |                                      |                   |
| British   |                                      |                   |
| Bro       |                                      |                   |
| adcasting |                                      |                   |
| Co        |                                      |                   |
| rporation |                                      |                   |
|           |                                      |                   |
| DARC:     |                                      |                   |
| Deutscher |                                      |                   |
| Amateur-R |                                      |                   |
| adio-Club |                                      |                   |
|           |                                      |                   |
| EN:       |                                      |                   |
| European  |                                      |                   |
| Standard  |                                      |                   |
| NF        |                                      |                   |
|           |                                      |                   |
| FICORA:   |                                      |                   |
| Finnish   |                                      |                   |
| Commu     |                                      |                   |
| nications |                                      |                   |
| R         |                                      |                   |
| egulatory |                                      |                   |
| Authority |                                      |                   |
|           |                                      |                   |
| IEC:      |                                      |                   |
| Inte      |                                      |                   |
| rnational |                                      |                   |
| Electro   |                                      |                   |
| technical |                                      |                   |
| C         |                                      |                   |
| ommission |                                      |                   |
|           |                                      |                   |
| MPHPT:    |                                      |                   |
| Ministry  |                                      |                   |
| of Public |                                      |                   |
| M         |                                      |                   |
| anagement |                                      |                   |
| Home      |                                      |                   |
| Affaires, |                                      |                   |
| Post and  |                                      |                   |
| Telecommu |                                      |                   |
| nications |                                      |                   |
| of Japan  |                                      |                   |
|           |                                      |                   |
| NB30:     |                                      |                   |
| Usage     |                                      |                   |
| Provision |                                      |                   |
| 30,       |                                      |                   |
| issued by |                                      |                   |
| German    |                                      |                   |
| RegTP in  |                                      |                   |
| January   |                                      |                   |
| 1999. It  |                                      |                   |
| contains  |                                      |                   |
| a         |                                      |                   |
| limiting  |                                      |                   |
| curve for |                                      |                   |
| the       |                                      |                   |
| radiation |                                      |                   |
| of        |                                      |                   |
| telecommu |                                      |                   |
| nications |                                      |                   |
| services  |                                      |                   |
| in and    |                                      |                   |
| alongside |                                      |                   |
| of cables |                                      |                   |
| (         |                                      |                   |
| including |                                      |                   |
| Cable TV, |                                      |                   |
| xDSL, and |                                      |                   |
| PLC) for  |                                      |                   |
| the       |                                      |                   |
| frequency |                                      |                   |
| range     |                                      |                   |
| from 9    |                                      |                   |
| kHz to 3  |                                      |                   |
| GHz.      |                                      |                   |
|           |                                      |                   |
| RA:       |                                      |                   |
| R         |                                      |                   |
| adiocommu |                                      |                   |
| nications |                                      |                   |
| Agency of |                                      |                   |
| U.K.      |                                      |                   |
|           |                                      |                   |
| RegTP:    |                                      |                   |
| The       |                                      |                   |
| R         |                                      |                   |
| egulating |                                      |                   |
| Admin     |                                      |                   |
| istration |                                      |                   |
| for       |                                      |                   |
| Telecommu |                                      |                   |
| nications |                                      |                   |
| and Posts |                                      |                   |
| of        |                                      |                   |
| Germany   |                                      |                   |
+-----------+--------------------------------------+-------------------+

**Table 3-3:** German NB30 Limits

  --------------------- ----------------------------- ------------- --------------
  **Frequency Range     **Limit of Peak Field         **Measuring   **Detector**
  (MHz)**               Strength at 3 meters          Bandwidth**   
                        (dBµV/meter)**                              

  \>1 to 30             40 -- 8.8 \* log~10~ (f~MHz~) 9 kHz         peak

  \>30 to 1000          27 (equivalent to radiated    not specified peak
                        power of 20 dBpW)                           
  --------------------- ----------------------------- ------------- --------------

**3.2.2.2 Proposed New Regulations**

Several proposals have been presented on a regional basis for
consideration to regulate emissions from cable and BPL equipment, and
the parts of these proposals relevant to BPL systems operating in the
frequency band of 1.7 -- 80 MHz are listed below.[^2] The first
proposal, from Germany and taken from NB30, is shown in Table 3-4.

**Table 3-4:** German Regional Proposal

  -------------------- -------------------------- ------------- --------------
  **Frequency Range    **Limit of Peak Field      **Measuring   **Detector**
  (MHz)**              Strength at 3 meters       Bandwidth**   
                       (dBµV/meter)**                           

  \>1 to 30            40 -- 8.8 \* log~10~       9 kHz         peak
                       (f~MHz~)                                 

  The limit is given                                            
  in terms of the                                               
  electric field                                                
  strength. Below 30                                            
  MHz the limit                                                 
  applies for the                                               
  magnetic field                                                
  strength, assuming                                            
  an intrinsic                                                  
  impedance of 377 Ω.                                           
  This proposal is                                              
  supported by                                                  
  Austria, Finland,                                             
  France, Germany,                                              
  Romania and                                                   
  Switzerland.                                                  
  -------------------- -------------------------- ------------- --------------

A second proposal, from Norway, is shown in Table 3-5.

**Table 3-5:** Norwegian Proposal

  ---------------------- ------------------------- ------------- --------------
  **Frequency Range      **Limit of Peak Field     **Measuring   **Detector**
  (MHz)**                Strength at 3 meters      Bandwidth**   
                         (dBµV/meter)**                          

  \>1 to 30              20 -- 7.7 \* log~10~      9 kHz         peak
                         (f~MHz~)                                

  Magnetic field data,                                           
  in dBµA/meter, are                                             
  measured with a loop                                           
  antenna. The                                                   
  equivalent E-field                                             
  data are converted                                             
  from the H-field data                                          
  by the factor of 51.5                                          
  dB which corresponds                                           
  to the free space                                              
  impedance of 120 Ω.                                            
  This proposal is                                               
  supported by Ireland.                                          
  ---------------------- ------------------------- ------------- --------------

A third proposal, from BBC of U.K. and NATO, is shown in Table 3-6.

**Table 3-6: Proposal from** BBC and NATO

  ----------------- ------------------------------- ------------- --------------
  **Frequency Range **Limit of Peak Field Strength  **Measuring   **Detector**
  (MHz)**           at 1 meter**                    Bandwidth**   

  3 -- 30           H~peak~ = -- 29.7 -- 8.15       9 kHz         peak
                    Log~10~ (f~MHz~), (dBµA/meter,                
                    measured)                                     

  3 -- 30           E~peak~ = 21.8 -- 8.15 Log~10~  9 kHz         peak
                    (*f* ~MHz~), (dBµV/meter,                     
                    calculated from H~peak~)                      

  The H-field data                                                
  are measured with                                               
  a loop antenna,                                                 
  and the E-field                                                 
  data are                                                        
  converted from                                                  
  the H-field data                                                
  by the factor of                                                
  51.5 dB. This                                                   
  limit is derived                                                
  with the                                                        
  reference noise                                                 
  level from ITU-R                                                
  Rec. P 372-7 and                                                
  the protection                                                  
  distance of 10                                                  
  meters where the                                                
  sensitivity of a                                                
  victim receiver                                                 
  degraded by less                                                
  than 0.5 dB. It                                                 
  is supported by                                                 
  the radio users                                                 
  (military,                                                      
  broadcasting,                                                   
  civil aviation,                                                 
  amateur, etc.) of                                               
  the LF, MF and HF                                               
  bands.                                                          
  ----------------- ------------------------------- ------------- --------------

A fourth proposal, from BPL manufacturers and utility industries and
taken from the FCC Part 15 limits, is shown in Table 3-7.

**Table 3-7:** Proposal by Certain BPL Proponents

+-----------------------+-----------------------+-----------+-----------+
| **Frequency (MHz)**   | **Field Strength at   | **        | **D       |
|                       | 30 meters**           | Measuring | etector** |
|                       |                       | Ba        |           |
|                       | **(µV/meter)**        | ndwidth** |           |
+-----------------------+-----------------------+-----------+-----------+
| 1.705 ‑ 30.0          | 30                    | 9 kHz     | q         |
|                       |                       |           | uasi-peak |
+-----------------------+-----------------------+-----------+-----------+

A comparison of these four proposals is shown in Figure 3-1. In this
figure, the data are scaled to a 10 meter measurement distance according
to §15.31 (f)(2) guidelines for measurement distance extrapolation under
30 MHz.

![](media/image1.wmf){width="6.25in" height="4.097222222222222in"}

**Figure 3-1: Comparison of Proposals for Regulating BPL Emissions**

**3.3 STUDIES**

### 3.3.1 Analyses of Interference from BPL Filed Under the FCC NOI 

Proponents and opponents of the Commission's NOI regarding Broadband
over Power Lines submitted relevant technical information and analyses
of the implications BPL will have on existing licensed services between
1.7 -- 80 MHz. Some of their key points are summarized in the following
paragraphs.[^3]

#### 3.3.1.1 Power Lines as Unintentional Radiators of BPL Signals

Ameren Energy Communications, Inc. (Ameren) analyzed the Medium Voltage
(MV) power line with respect to its ability to act as an unintentional
antenna for frequencies below 30 MHz.[^4] In their analysis, Ameren
stated that a two-conductor power line segment, driven differentially
(*e.g.*, an \"aerial\" mode[^5]), supports mostly transverse
electromagnetic modes (TEM) of propagation and acts like a wave guide.
This line radiates only at points of discontinuity, such as at line
terminations, junctions with other lines, sharp line turns, and at power
distribution equipment such as transformers and capacitors. They further
state that reflections at the receiving end of the power line cause the
formation of two opposite traveling waves, with radiation at both ends
of the line.

Ameren noted that when calculating the radiation efficiency and gain of
the power line, the source impedance at the BPL transmitter should be
fixed and the load impedance should be allowed to vary. This contrasts
with a line operating as a traveling wave antenna in that load impedance
should be matched to the line's characteristic impedance (between 350 to
420 for frequencies between 1 and 30 MHz). Their calculations show that
as the line termination varies, not only does the line's radiation
efficiency and gain change, the ability of the fixed source to couple
power onto the power line decreases with the load mismatch. Ameren
indicated that a single line is expected to be an inefficient radiator.
Further, Ameren calculated the array factor for two conductors and show
a 17% increase in radiation over the single conductor case. Ameren
believes that transmission lines carrying TEM waves should not be
compared with linear array elements as their radiation mechanisms are
different.

Ameren also discussed the case of interconnected segments of MV power
distribution line and pointed out that the radiation pattern is
determined by the current distribution in the lines running in different
directions, and the radiation is likely to be more isotropic. This, they
believe, will result in lower gains and increased attenuation of signals
as they divide amongst each interconnected segment and reflects at
discontinuities. Ameren concludes that the strongest radiation will be
at the source and that is the critical part of the system for
determining radiation of BPL signals.

The ARRL submitted a paper presenting calculated antenna gains and
patterns as a function of frequency for a simple power line model.[^6]
Their results indicated that as frequency increases, the power line acts
more like an antenna, with a complex and highly directive radiation
pattern.

In another paper, ARRL described their model of a MV distribution power
line and compared the following three methods of injecting the BPL
signal into the model[^7]:

-   Differential feed between two phases, with the feed at one end of
    the power line;

-   One phase to Earth ground, with the feed in the center of the line;

-   Single phase fed differentially; with one conductor grounded to a
    relatively poor RF ground and the ungrounded phase feed point was
    offset from center.

Based on their model, ARRL presented results for the antenna gain of the
power line, with the single phase -- differential feed with one
conductor grounded as being the worst case. This case resulted in higher
antenna gain for the modeled power line, and greater coupling to the
simulated amateur radio antennas included in their model. ARRL noted
that the calculated gain for this power line at 14 MHz rivaled many
amateur HF antennas. A final observation was made that the radiated
emission patterns for this model were very complex and that the peak
radiation at 3.5 MHz is skyward.

#### 3.3.1.2 Existing Part 15 Rules Regarding BPL Signals

Ameren questioned the validity of using a loop antenna to measure
magnetic field strength.[^8] Ameren pointed out that power lines act as
"large radiators" and measurements close to power lines (e.g. 30 meters)
are in the near field where the value of free space impedance typically
used in the far field, 377 Ω (51.42 dB), is no longer valid. They
presented graphs of electric (E) and Magnetic (H) fields, and H field +
51.42 dB to make the case that the far field value of free space
impedance is incorrect in the near field.

Ameren stated that the estimation error from the use of a loop antenna
could be as high as 10 dBV/m for measurements made along the power line,
and as high as 20 dBV/m moving away from the power line, even as far out
as 700 meters. The model used for this analysis showed that the peak
field strength is above the horizon, at an elevation angle of 12. Ameren
concluded that the loop introduces significant measurement errors near
power lines and recommended use of a monopole antenna for BPL
measurements.

In another paper, ARRL calculated the conducted emissions power levels
based on several BPL manufacturers submissions to the Commission in
response to the NOI.[^9] ARRL stated that their calculations show a
resultant level of conducted emissions exceeding 47 C.F.R. §15.107(a).
ARRL further stated that, based on its understanding of how BPL couplers
function, the typical losses for these couplers would lead to widespread
radiated or conducted emissions.

ARRL addressed the possibility that inaccuracies may occur in measured
results when following current Part 15 rules.[^10] ARRL stated that from
their model of power lines, BPL radiation patterns are complex and it
would be difficult to predict where to make measurements to obtain the
peak value of the electrical field. Another potential source of error
may arise in arriving at an extrapolation factor, as they indicated that
the HF electric field does not fall off at a 40 dB/decade inside 30
meters. Using the results from their power line model, ARRL noted that
the power line field strength is greater above the power lines;
therefore, measurements made near ground (1m) will typically
underestimate the peak field strength.

To maximize the likelihood that measured results accurately characterize
the BPL field strength, ARRL recommended in-situ testing at closely
spaced distance intervals above, below, and to the sides of BPL system
installations. The practice of using 3 "typical" installations to
characterize emissions is considered by ARRL to be unrealistic and will
result in measurements unrepresentative of the emissions in a real
installation. Finally, ARRL noted that there are definitely standing
waves in the simulation results for the power line modeled.

Using their power line model, ARRL calculated the received signal level
from BPL emissions in the vicinity of an amateur radio antenna and the
expected increase in noise floor. The BPL transmitted power spectral
density was estimated and, from this, ARRL calculated that the radiated
field strength will exceed Part 15 limits.[^11] ARRL assumed ideal
(high) coupling between the power line and the amateur radio antenna,
and that the antenna is located in a direction where the BPL signal's
radiated emissions are at their peak. In addition, ARRL used the results
of their model of the power lines to estimate power line \"antenna
gain.\" ARRL further described potential measurement errors that can
mistakenly lead BPL vendors to believe that they are meeting Part 15
limits.

In a paper by the BBC, various proposals were considered for limits on
emissions that are under review in CEPT SE35 (a European technical
committee) and evaluated the amount of protection that these limits
would provide to broadcast receivers near cabling carrying xDSL and PLT
(BPL) signals.[^12] The author concluded that none of the proposed
limits adequately protect broadcast reception and that a proposal
limiting the increase in noise floor appears to offer the most promise.

#### 3.3.1.3 BPL Impact on Existing Licensed HF Communications Services

The ARRL modeled the reliability of HF communications for various noise
floor levels.[^13] Their modeling used noise floor levels for a quiet
residential environment, the ITU-R Recommendation P.372.8 (2003) for
median noise level in a residential environment, the ITR-R
Recommendation level +10 dB, and the noise plus BPL signal level
calculated by ARRL for a wide-scale BPL deployment where these devices
operate at the maximum field strength allowed under Part 15. ARRL
modeled these conditions at 5 MHz and 14 MHz using the VOACAP
inverse-area coverage program.

A number of plots of HF link availability were provided in this ARRL
report. The results indicated that the reliability of HF communications
is already degraded when operating a receiver in the presence of the
ITU-R median level noise, and if BPL use increased the noise floor by 10
dB, or to the level ARRL says will result from widespread BPL deployment
at Part 15 limits, ARRL concludes that worldwide HF communications will
be severely degraded.

In another paper, the BBC analyzed the cumulative effects of wide-scale
deployment of xDSL and BPL. The BBC considered the skywave propagation
effects on aircraft receivers and distant ground-based receivers
due.[^14] The author concluded from his analysis that the extent of
skywave interference to aircraft and ground-based receivers from
widespread xDSL/PLT system deployment may not be negligible. The author
suggests that the relevant competent authorities should further
investigate this interference potential.

**3.3.2 International Telecommunications Union (ITU) Activities**

At least two of the three ITU Sectors have addressed BPL: the
Telecommunications Standards Sector (ITU-T) and the Radiocommunications
Sector (ITU-R). Working documents of the Study Groups in both of these
sectors are not freely available to the public, so descriptions of
current documentation and activities are presented in this section
without comprehensive citations.[^15]

**3.3.2.1 ITU-T Study Group 5**

In mid-2003, ITU-T Study Group 5 approved Recommendation K.60, which
addresses \"Emission Limits and Test Methods for Telecommunication
Networks\". Specifically, its intended application is for investigation
of complaints of radio interference and its scope includes all
telecommunications networks using LV AC electrical power lines and
frequencies between 9 kHz and 400 GHz. The recommended \"target\" field
strength limits for the 1.7-80 MHz frequency range are listed in Table
3-8. Associated measurement and administrative procedures are specified
in the Recommendation. The procedures feature a number of interference
mitigation steps that should be taken by the parties directly involved
before consideration is given to filing an interference complaint with
government authorities.

**Table 3-8: Target Electric Field Strength Limits of ITU-T Rec. K.60**

  --------------- -------------- ---------------- ----------------- -----------------
  **Frequency**   **Field                         **Measurement**   **Measurement**
                  Strength                                          
                  (dBV/m)**                                         

  **Range (MHz)** **Peak**       **Quasi-Peak**   **Distance**      **Bandwidth**

  1 to 30         52 - 40 log    40 - 20 log (f)  3 m               9 kHz
                  (f)                                               

  30 to 230       52 - 8.8 log   40 - 8.8 log (f) 3 m               120 kHz
                  (f)                                               

  NOTES: f =                                                        
  frequency                                                         
  (MHz); below 30                                                   
  MHz, 377 Ω                                                        
  impedance is                                                      
  assumed in                                                        
  estimating                                                        
  electric field                                                    
  strength from                                                     
  measured                                                          
  magnetic field                                                    
  strength; only                                                    
  the quasi-peak                                                    
  limit applies                                                     
  if background                                                     
  noise is too                                                      
  high for a peak                                                   
  measurement.                                                      
  --------------- -------------- ---------------- ----------------- -----------------

**3.3.2.2 ITU-R Study Group 1**

Working Parties 1A (Spectrum Engineering) and 1C (Monitoring) met in
November 2003 and examined BPL studies in response to Questions 221/1
and 218/1.[^16] France presented an extensive, non-conclusory European
study of potential interference from BPL and other wire-bound
telecommunications systems. The United States (represented by ARRL)
presented a paper outlining BPL interference measurement and analysis
considerations consistent with the Commission\'s open BPL proceeding.
Korea presented a paper describing an approach for measuring BPL
emissions in a laboratory environment. A Liaison Statement presenting
relevant Study Group 6 (broadcasting service) studies was reviewed.
Insofar as Working Party 1A is the lead ITU-R group for development of
recommendations regarding potential interference from BPL systems, it
requested information from all other Working Parties responsible for
signal propagation models and analysis and matters affecting specific
radio services. Working Parties 1A and 1C both expect to complete their
BPL studies in 2005.

**3.3.2.3 ITU-R Study Group 3**

The November 2003 meetings of Study Group 3, Working Parties 3J, 3K, 3L
and 3M, generated extensive discussions on propagation aspects of Power
Line Telecommunication (PLT) systems. The Study Group 3 Chairman
declared this to be one of the three most important topics for these
meetings. Subgroups 3K-1 and 3L-2 spent appreciable time discussing PLT
systems and Subgroup 3J-C contributed relevant information regarding
environmental noise. Working parties 3J, 3K and 3L jointly drafted a
liaison statement to Working Party 1A, identifying concerns and
suggesting methods of estimation of PLT signal radiation levels.

The concerns expressed included: the unbalanced nature and diverse
characteristics of power lines; the possibility of both point and line
sources of radiation; power aggregation of emissions from multiple
sources; and the presence of both ground and sky waves. It was noted
that in developing criteria for acceptable PLT use of radio frequencies,
measurements of both electric and magnetic fields must be considered
because of the unknown relationship between these fields in the
near-field. It was suggested that: a model such as NEC be used for
estimation of radiation; either ITU-R Rec. P. 368 or the software GRWAVE
be used for evaluating ground wave propagation of PLT emissions; and
ITU-R Rec. P. 533 be used for evaluating PLT propagation via sky wave.
It was also suggested that ITU-R Rec. P. 372 be used for estimating
levels of noise.

In addition to the Liaison Statement, Working Party 3L drafted a new
question and formed a new Correspondence Group to work on the PLT
Communications. The draft new question focused on prediction methods and
models applicable to PLT systems. Defined studies were also given high
priority. The defined studies address radiation mechanisms of PLT
systems, modeling techniques, effects of local ground planes and
conductors, methods of aggregation, propagation models for calculation
of interference and measurement of radiated fields in the near field.
The Correspondence Group will exchange ideas and communicate outputs of
various studies under progress for review by the international group.

**3.3.2.4 ITU-R Study Group 6**

In ITU WP 6E, the European Broadcasting Union (EBU) submitted a document
recommending revision of PLT field strength limits and measurement
distance identified in an earlier study. This contribution suggested
three shortcomings in the earlier study. First, digital broadcasting
transmission, not Amplitude Modulation transmission, should be used to
derive the allowable PLT signal strength. Second, the required
signal-to-noise level should not support only a relatively
interference-tolerant channel operating in a rugged mode with restricted
capacity. Third, the 3-meter measurement distance specified in the NB30
limit (Table 3-3) is unrealistically large for indoor reception.
Therefore EBU concluded that the NB30 limits were unacceptably lax by a
large margin and proposed that: (1) the maximum allowable PLT
interference should be at least 10-20 dB lower; and (2) reception at
1-meter and larger distances from the PLT emission source should be
protected.

**3.3.3 Other Technical Literature**

Appendix B summarizes additional technical literature that was not filed
in response to the BPL Inquiry.

**3.4 SUMMARY**

Studies performed by other parties and applicable FCC and foreign
regulations were reviewed to ensure that NTIA's studies would address
important interference mechanisms and factors as well as potential means
for effectively accommodating BPL and radio systems. NTIA noted that BPL
has been implemented with success in some countries, while other
countries have postponed implementation of BPL systems until further
interference studies are being conducted. Still others have withdrawn
their approval for operation of BPL systems after experiencing
interference problems. Several emission limits have been adopted or
proposed for evaluation on international, national and regional bases.
Most studies have been oriented to determine whether interference will
occur at the variously proposed limits. In contrast, NTIA has oriented
its study to find a solution that accommodates BPL systems while
appropriately managing the risk of interference to radio systems.

Technical information and analyses submitted in response to the FCC NOI
included several relevant observations. BPL signals unintentionally
radiate from power lines, although there is substantial disagreement as
to the strength of the emissions and their potential for causing
interference to licensed radio services. Analyses indicate that the peak
field strength due to unintentional BPL radiation occurs above the
physical horizon of power lines. Current Part 15 measurement techniques
may significantly underestimate the peak field strength generated by BPL
systems as a result of using a loop antenna in the near field;
performing measurements with an antenna situated near ground level
(*e.g.*, 1 meter); and measuring emissions in the vicinity of BPL
devices without also considering emissions from the power lines.

[^1]: *See* 47 C.F.R. §15.3(f). Carrier current system. A system, or
    part of a system, that transmits radio frequency energy by
    conduction over the electric power lines. A carrier current system
    can be designed such that the signals are received by conduction
    directly from connection to the electric power lines (unintentional
    radiator)...

[^2]: European Conference of Postal and Telecommunications
    Administrations (CEPT) Electronic Communications Committee (ECC)
    Report 24, "PLT, DSL, Cable Communications (Including Cable TV),
    LANs and Their Effect on Radio Services," Section 7.

[^3]: Inclusion or exclusion of any analysis in this section has no
    significance; NTIA reviewed all filings under the BPL Inquiry.

[^4]: *See* Reply Comments of Ameren Energy Communications Inc., BPL
    Inquiry, August 20, 2003, ("Ameren Reply Comments").

[^5]: As described in Ameren Reply Comments, \"aerial modes\" direct
    their peak radiation skyward.

[^6]: *See* *Power Lines as Antenna From 100 kHz to 50 MHz*, Ed Hare,
    Exhibit A to Comments of ARRL, BPL Inquiry, July 7, 2003, ("ARRL
    Comments").

[^7]: *See* *Methods of Feeding Overhead Electrical Power-Line
    Distribution Lines With BPL Signals and the Relationship of These
    Methods to the Radiated Emissions of the Conductors*, Ed Hare,
    Exhibit B to ARRL Comments.

[^8]: *See* *Use of Loop Antennae near Large Radiators*, Appendix to
    Ameren Reply Comments.

[^9]: *See* *Broadband Over Power Line Devices and Conducted Emissions*,
    Ed Hare, Exhibit B to Reply Comments of ARRL, BPL Inquiry, August
    20, 2003, ("ARRL Reply Comments").

[^10]: *See* *Electric and Magnetic Fields Near Physically Large
    Radiators*, Ed Hare, Exhibit D to ARRL Comments.

[^11]: *See* *Calculated Levels from Broadband Over Power Line Systems
    and their Impact on Amateur Radio Communications Circuits*, Ed Hare,
    Exhibit C to ARRL Comments.

[^12]: *See* *AM Broadcasting and Emissions from xDSL/PLT/etc.*, J. H.
    Stott, BBC R&D White Paper WHP-012, Attachment to Comments of David
    A. Lewis, BPL Inquiry, June 23, 2003, ("David Lewis Comments").

[^13]: *See* *Impact of Man-Made Noise From Broadband Over Power Line
    Systems Operating at the FCC Part-15 Radiated Emissions Limits on
    Worldwide HF Communications*, Ed Hare, Exhibit of ARRL, BPL Inquiry,
    August 20, 2003, ("ARRL Exhibit").

[^14]: *See* *Cumulative effects of distributed interferers*, J. H.
    Stott, BBC R&D White Paper WHP-004, Attachment to David Lewis
    Comments.

[^15]: Information on obtaining access to ITU documents, *e.g.*, via
    corporate membership, is provided at www.itu.int.

[^16]: The texts of Question 221/1, \"Compatibility between
    radiocommunication systems and high data rate telecommunication
    systems using electricity power supply or telephone distribution
    wiring,\" and Question 218/1, \"Techniques for measurement of
    radiation from high data rate telecommunication systems using
    electrical power supply or telephone distribution wiring,\" are
    freely available at www.itu.int.