DRAFT EFH 1/13/04
Contribution to IEEE BPL Study Group White Paper
Compatibility with Radio Services
1.
Introduction
This section of the document does not replace the FCC regulations that apply to the
responsibilities of BPL operators and operators toward licensed radio services. It provides
general information about the rules governing emissions and interference and provides
guidance to BPL manufacturers and operators on how to design and use BPL equipment in a
way that will comply successfully with applicable FCC regulations.
It is not the goal of this document to define acceptable levels of interference. Those are
defined in the FCC CFR 47 Part 15 rules and by the needs and nature of the particular radio
services that may be affected by BPL. This document provides information about the rules
and radio services that may be in use near BPL. It also offers general recommendations on
levels and practices that will reduce the probability of interference to a small enough level
that any remaining harmful interference can be effectively addressed on a case-by-case basis.
The FCC has noted that the interference potential of BPL is generally low. The interference
potential of BPL is limited by the FCC’s rules that limit the emissions from unlicensed
devices. However, radio-frequency emissions from BPL systems do have the potential of
causing interference to licensed radio services. Irrespective of probability, any interference
that does occur from any unlicensed device regulated by Part 15 of the FCC rules must be
corrected by the operator of the device.
The degree of potential interference is related to the strength of the radiated emissions from
BPL systems and the signal levels being used by radio services in use near BPL systems. The
strength of these emissions depends on a number of factors, such as:
o
o
o
o
o
The frequencies being used
The BPL power level into the lines
The radiation pattern and efficiency of the power line
The path attenuation between the power line and the radio receiving antenna
The sensitivity and other characteristics of the radio receiving system.
There is also the possibility that radiation from licensed radio service transmitting stations
near BPL installations may cause temporary loss or slowdowns of BPL data transfers.
2.
Regulatory Requirements
The radio-frequency spectrum over the 1.8-80 MHz range is divided into bands, each of
which is allocated to one or more licensed radio service. Internationally, theses bands and
services are defined by the International Telecommunication Union (ITU) Radio
Regulations. Domestically, they appear in the FCC rules:
http://www.access.gpo.gov/nara/cfr/waisidx_01/47cfr2_01.html
and the NTIA Manual, a publication of the National Telecommunications and Information
Administration:
http://www.ntia.doc.gov/osmhome/redbook/redbook.html.
See also: http://www.ntia.doc.gov/osmhome/allochrt.pdf.
Section 15.12 of the International Radio Regulations states:
“Administrations shall take all practicable and necessary steps to ensure that the operation of
electrical apparatus or installations of any kind, including power and telecommunication
distribution networks, but excluding ISM, does not cause harmful interference to a
radiocommunication service…”
The regulatory requirements in the United States are described in the FCC Report and
Order (R&O) in ET Docket No. 04-37 and ET Docket No. 03-104 (FCC 04-245), available at:
http://svartifoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=65168827
67
The final rule changes to CFR 47 Part 15 relating to BPL are contained in Appendix B of the
R&O.
The Part 15 rules facilitate BPL use and deployment by defining the parameters that will
limit the interference potential of BPL. The following are the principle means by which this
is accomplished:
o The rules set absolute-maximum limits on the emissions from BPL devices. (§15.611(b))
o The test procedures that are used to determine the emissions are defined (§15.613 and
Appendix B)
o These limits generally limit the interference potential of BPL. However, if harmful
interference as defined in the rules does occur, the operator of a BPL device is required
to correct the interference. (§15.5)
o BPL devices and systems must use adaptive interference mitigation techniques to avoid
frequencies that are used locally by licensed radio operations. (§15.611(c))
The information in this document section provides guidance on identifying frequencies that
are likely to be used by licensed radio operations locally in various environments in which
BPL may be deployed. This information will enable BPL operators to avoid causing harmful
interference to radio users.
In general, as stated by the FCC in the R&O, the attenuation of frequency notches described
in Sec. 15.611(c)(1)(i) and (ii) would be a reasonable level to minimize the likelihood of
harmful interference to NTIA-governed operations from BPL systems. However, in some
cases, the weak nature of the other non-government licensed signals being used, the
sensitivity of the receiving equipment being used and the sensitivity and location of the
receiving antenna being used may require additional protection to avoid causing harmful
interference.
As described in the Part 15 rules, a BPL manufacturer or operator of a BPL system should
select the appropriate emissions levels and suppression techniques for locally used spectrum
to avoid harmful interference. This would generally be based on an assessment of what local
licensed radio use would reasonably be expected to occur in the vicinity that BPL will be
operating and the nature of those services. In some cases, although some types of radio
operation is known to be common in specific BPL environments, the specific location of such
users may be unknown.
3.
Best Practices to Avoid Interference to Radio Service Receivers in Residential Areas
The potential harmful interference to locally used spectrum is documented in a letter dated
September 13, 2004 from Mr. Fredrick R. Wentland (NTIA) to Mr. Edmond Thomas (FCC),
in re: Amendment of Part 15 Regarding New Requirements and Measurement Guidelines
for Access Broadband over Power Line Systems (FCC 04-29), ET Docket No. 04-37,
available at:
http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6516492213.
3.1 Amateur Service – A radiocommunication service for the purpose of self-training,
intercommunication and technical investigations carried out by amateurs, that is, by duly
authorized persons interested in radio technique solely with a personal aim and without
pecuniary interest.
Internationally, amateur service emergency communications is documented in Article 25 of
the Radio Regulations and Recommendation ITU-R M.1042-2, “Disaster communications in
the amateur and amateur-satellite services.”
In the United States, the basis and purpose of the Amateur Radio Service are specified in 47
CFR 97.1, which states “the value to the public as a voluntary noncommercial
communication service particularly with respect to providing emergency communications.”
Amateur (fixed and mobile) stations are typically situated in residential areas in close
proximity to electric power lines. While amateur bands are not excluded from BPL use by 47
CFR 15.615(f), best engineering practice would be to exclude amateur bands in areas where
amateur operation is expected to occur. Amateur mobile operation is common on public
roads and highways.
Amateur service allocations in the 1.8-80 MHz range are authorized in 47 CFR 97.301 are as
follows:
FREQUENCY BAND
1,800 – 2,000 kHz
3,500 – 4,000 kHz
5,332, 5,348, 5,368,
5,373 and 5,405 kHz
7,000 – 7,300 kHz
10,100 – 10,150 kHz
14,000 – 14,350 kHz
18,068 – 18,168 kHz
21,000 – 21,450 kHz
24,890 – 24,990 kHz
28 – 29.7 MHz
50 – 54 MHz
3.2 High Frequency Broadcasting Service (HFBC) – A radiocommunication service in
which the transmissions are intended for direct reception by the general public.
HFBC receivers are usually situated in residential areas in close proximity to electric power
lines. Section 4.11 of the International Radio Regulations states:
“Member States recognize that among frequencies which have long-distance propagation
characteristics, those in the bands between 5 and 30 MHz are particularly useful for longdistance communications; they agree to make every possible effort to reserve these bands for
such communications…”
While HFBC bands are not excluded from BPL use by 47 CFR 15.615(f), good engineering
practice would be to exclude the HFBC bands in areas where HFBC receivers are expected
to be in use.
HFBC allocations in the 1.8-30 MHz range applicable to ITU Region 2 are as follows:
FREQUENCY BAND
5,900 – 6,200 kHz
7,300 – 7,350 kHz
9,400 – 9,900 kHz
11,600 – 12,100 kHz
13,570 – 13,870 kHz
15,100 – 15,800 kHz
17,480 – 17,900 kHz
18,900 – 19,020 kHz
21,450 – 21,850 kHz
Note: Tropical broadcast bands of 2300-2495 kHz, 3,200-3,400 kHz, 4,750-4,995 kHz and
5,005-5,060 kHz are not included in the above table, although some short wave listeners in
the United States are interested in receiving them. Also, the band 25,670–26,100 kHz
allocated to the broadcasting service is omitted from the above list because it is not often
used. In addition, there are numerous out-of-allocated-band broadcasts not included in the
above table.
3.3 Standard Frequency and Time Signal Service – A radiocommunication service for
scientific, technical and other purposes, providing the transmission of specified frequencies,
time signals, or both, of stated high precision, intended for general reception.
While Standard Frequency and Time Signal bands are not excluded from BPL use by 47
CFR 15.615(f), best engineering practice would be to exclude these bands from BPL use in
areas where reception of such signals is likely. Many amateur operators make use of these
time signals for their frequency, time and propagation information.
Frequency and time signals are transmitted in the United States by radio station WWV,
Boulder, CO and received among other places in residential areas. Frequencies are:
FREQUENCY BAND
2,495 – 2,501 kHz
4,995 – 5,003 kHz
10,995 – 10,003 kHz
14,990 – 15,005 kHz
19,995 – 20,010 kHz
Note: There is an additional allocation to the Standard Frequency and Time Signal Service
of 24,990–25,005 kHz, however it is not currently used by WWV.
3.4
Citizens Band Radio Service
According to 47 CFR 95.401, “The Citizens Band (CB) Radio Service–a private, two-way,
short-distance voice communications service for personal or business activities of the general
public.” Many CB stations are situated in residential areas or operate on public roads from
mobile stations. Some CB stations are used for emergency services, which may include “first
responders,” such as fire and rescue departments in smaller communities.
Radio frequency channels used by CB are specified in 47 CFR 95.407, ranging from 26,960
to 27,410 kHz. Good engineering practice would be to avoid these frequencies.
3.5 Other – Write section pointing to FCC resources to identify licensees by geographical
location and frequency.
3.6 – Write section on the 13 bands on which BPL operation is prohibited altogether to
protect certain government spectrum?
4.
Availability of Frequency Bands for BPL
NOTE: This table as written shows all of the spectrum discussed above. What is the
concensus of this group on whether it should be presented all in one piece as shown below, or
whether it should be broken down by category?
Frequencies Not Available for BPL
Reason
See 47 CFR 15.615(f)(3)(i) for certain 4 km
Coordination Areas
1,700-38,250
See 47 CFR 15.615(f)(3)(ii) for certain 4 km
Coordination Areas
1,700-80,000
See 47 CFR 15.615(f)(3)(iii) for certain 1 km
Coordination Areas
1700-30000
See 47 CFR 15.615(f)(3)(iv) for 37 km radar
Coordination Areas
Bands (kHz)
1,700 – 30,000
1,800 – 2,000
2,173.5 – 2,190.5
Frequencies Available for BPL
Bands (kHz)
Bandwidth (kHz)
1,700 – 1,800
100
2,000 – 2,173.5
2,173.5 – 2,190.5 outside
Exclusion Zones
2,300 – 2,495 outside Tropical
Zone
173.5
17
2,501 – 2,850
349
Amateur 160 m Band
2,300 – 2,495
Mobile (Distress and Calling) See 47 CFR
15.615(f)(2) for Exclusion Zones
Tropical Broadcast Band
2,495 – 2,501
Standard Frequency and Time Signals
2,850 – 3,025
Excluded Frequency Band (Aeronautical
195
Mobile (R)) See 47 CFR 15.615(f)(1)
3,400 – 3,500
3,500 – 4,000
4,650 – 4,700
Excluded Frequency Band (Aeronautical
Mobile (R)) See 47 CFR 15.615(f)(1)
4,995 – 5,003
Standard Frequency and Time Signals
5,330.5 – 5,406.5
3,025 – 3,400
375
4,000 – 4,650
650
4,700 – 4,995
295
5003 – 5,330.5
327.5
Excluded Frequency Band (Aeronautical
Mobile (R)) See 47 CFR 15.615(f)(1)
Amateur 80 m Band
Amateur 60 m Band
5,406.5 – 5,450
5,450 – 5,680
Excluded Frequency Band (Aeronautical
Mobile (R)) See 47 CFR 15.615(f)(1)
5,990 – 6,200
HF Broadcasting
6,525 – 6,685
Excluded Frequency Band (Aeronautical
Mobile (R)) See 47 CFR 15.615(f)(1)
7,000 – 7,300
7,300 – 7,350
Amateur 40 m Band
HF Broadcasting
8,815 – 8,965
Excluded Frequency Band (Aeronautical
Mobile (R)) See 47 CFR 15.615(f)(1)
9,400 – 9,900
HF Broadcasting
9,995 – 10,005
10005 – 10100
Standard Frequency and Time Signals
Excluded Frequency Band (Aeronautical
Mobile ®) See 47 CFR 15.615(f)(1)
Amateur 30 m Band
10,100 – 10,150
11,275 – 11,400
Excluded Frequency Band (Aeronautical
Mobile (R)) See 47 CFR 15.615(f)(1)
11,600 – 12,100
HF Broadcasting
13,260 – 13,360
Excluded Frequency Band (Aeronautical
Mobile (R)) See 47 CFR 15.615(f)(1)
13,570 – 13,870
HF Broadcasting
14,000 – 14,350
Amateur 20 m Band
14,990 – 15,005
Standard Frequency and Time Signals
15,100 – 15,800
HF Broadcasting
5,680 – 5,990
310
6,200 – 6,525
325
6,685 – 7,000
315
7,350 – 8,815
1,465
8,965 – 9,400
435
9,900 – 9,995
95
10,150 – 11,275
125
11,400 – 11,600
200
12,100 – 13,260
1,160
13,360 – 13,570
210
13,870 – 14,000
130
14,350 – 14,990
640
15,005 – 15,100
95
15,800 – 17,480
1,600
17,480 – 17,990
17,900 – 17,970
HF Broadcasting
Excluded Frequency Band (Aeronautical
Mobile (R)) See 47 CFR 15.615(f)(1)
18,068 – 18,168
Amateur 17 m Band
18,900 – 19,020
HF Broadcasting
21,000 – 21,450
21,450 – 21,850
Amateur 15 m Band
HF Broadcasting
21,924 – 22,000
Excluded Frequency Band (Aeronautical
Mobile (R)) See 47 CFR 15.615(f)(1)
24,890 – 24,990
Amateur 12 m Band
26,960 – 27,410
Citizens Band
28,000 – 29,700
Amateur 10 m Band
50 – 54 MHz
Amateur 6 m Band
74.8 – 75.2 MHz
(TV channels 2 – 4)
Excluded Frequency Band (Aeronautical
Radionavigation) See 47 CFR 15.615(f)(1)
(TV channels 5 – 6)
5.
Other Best Practice Provisions
5.1
“Notch” Filtering
17,970 – 18,068
98
18,168 – 18,900
732
19,020 – 21,000
1,980
21,850 – 21,924
74
22,000 – 24,890
2,890
24,990 – 26,960
1,970
27,410 – 28,000
590
29,7 – 50 MHz
20.3 MHz
54 – 74.8 MHz
20.8 MHz
75.2 – 80 MHz
4.8 MHz
As a practical matter, the attenuation of at least 20 dB provided in CFR 15.611(c)(i) and 10
dB in CFR 15.611(c)(ii), respectively, are not sufficient to mitigate interference to all radio
receivers of licensed radio services located in residential areas close to BPL systems. The
most simple implementation of best practice is to exclude frequency bands in the tables
above, based on whether those users are reasonably expected to be located in the area where
BPL is deployed.
A good design goal for the BPL industry in general would be to attain 40 dB of attenuation
of emissions in frequency bands being protected but in no case less than 30 dB. In all cases,
the degree of attenuation of emissions in spectrum that is to be protected is determined by
the actual levels that cause harmful interference. If instances of harmful interference can be
reduced to a practical number, those remaining cases can be best addressed on a case-bycase basis.
5.2
Response Time
CFR 15.615(d) requires that the local BPL operator resolve complaints of harmful
interference within a “reasonable time period” and within 24 hours from public safety users.
Best practice would be to reduce the response time substantially to 24 hours in all cases and
within 1 hour for public safety services.
6. Other information?
Describe techniques to limit BPL emissions levels?
Describe more about operating paramater of licensed stations?
Statistics on numbers of stations and types of operation?