Subject: [NEXTEL-1] BPL" Broadband over Power Lines Information Page

From: [email-masked]
Date: Mon, 13 Oct 2003 11:39:52 -0400

BPL" Broadband over Power Lines Information Page
Report into Broadband Power Line Technology in Australia
(with Particular Emphasis to it’s Effect on HF Radio.)

This report compiled by Phil VK2DKN is from a review of available literature and
attendance at the Powerline Broadband Conference held by Buddecom in Sydney on
17th September 2003. Valuable contributions were made by Phil Wait, Ron Jackson,
Graham Wilson, Chris Jones, and Owen Duffy. This report is by no means exhaustive
on the subject and much material is anecdotal and verbal in nature. This report is
intended as a guide only and further research needs to be done if any statements
are taken as fact.

Background

Broadband Power Line (BPL) is a form of power line carrier technology (PLC) using
existing power line infrastructure to deliver broadband services to homes and
business. Power Line Communications has been around for a very long time from
simple narrow band signalling and control systems, (the tones you hear over your
stereo), to in-building spread spectrum systems such as "Home-Plug", (now
available from retail outlets), to the multi home broadband distribution system –
BPL.  BPL is a technology in the very early stages of adoption. Systems are
installed throughout Europe, USA, Asia, Africa, and New Zealand. Most of these
systems are small trials, however commercial roll-out is happening now in Europe
and the U.S.  According to PLC company representatives at the Sydney conference,
150,000 homes have BPL available in the U.S., and Fiji is about to adopt BPL
technology in October with the help of Development Bank funding ahead of a
proposed rollout throughout the nations of the South Pacific. Hong Kong, Malaysia,
Singapore, and Indonesia are also adopting the technology.
BPL is projected to have 9% of the broadband traffic in Europe by 2008. The news
is not all supportive of BPL technology,
and Japan has rejected the technology due to interference problems and pending
further investigation,
http://www.jarl.or.jp/English/4_Library/A-4-1_News/jn0208.htm.

In Australia the utility companies are very interested in BPL technology and the
Federal Minister, Senator Richard Alston, has commissioned a report on the
suitability of BPL technology to the Australian environment, (Parsons Brinckerhoff
Associates).  While acknowledging some technical difficulties, that report is
likely to be very supportive of the speedy introduction of BPL technology in
Australia.

The Interference Problem

The case for and against the adoption of BPL is complex and there are many issues
to work through on both sides, a major issue being the cross-interference problem.
The frequencies used are between DC and 80 MHz (different systems use different
frequencies) and there are several modulation schemes. Most BPL systems in present
use are OFDM (orthogonal frequency-division multiplexing – essentially a
multi-carrier system) or DSSS (direct-sequence spread spectrum). The
peak-to-average ratio of these systems can vary, depending on how many carriers
are present in a given measurement channel.  OFDM has the advantage of being able
to dynamically block out parts of the spectrum in response to interference, (A
good primer on OFDM is at http://www.wi-lan.com (click on technology, then white
papers).

Power lines make very poor RF transmission lines, are full of discontinuity’s, and
are notorious radiators of electromagnetic
noise. The gain of the power-line as a radiator increases rapidly with frequency -
a radiating conductor with relatively low
emissions at 0.1 MHz can have emissions tens of dB higher at HF. (Calculated
Levels from Broadband Over Power Line
Systems and their Impact on Amateur Radio Communications Circuits, Ed Hare, ARRL,
July 2003). The interference potential
from BPL to other spectrum users working with weak signals in the HF and low VHF
spectrum is very high and extremely
widespread. This has been clearly demonstrated by ARRL testing of trial BPL
systems operating in the U.S. as well as testing
in many other countries including Japan and in Europe,
http://www.arrl.org/tis/info/html/plc/.

BPL is said to be a polluter of the radio spectrum, causing a large rise in the
`noise floor’ in urban areas akin to "radio smog".
The introduction of BPL systems could make a mockery of existing EMC legislation
requiring manufacturers of electronic and
electrical equipment to meet rigid emission limits designed to protect the radio
"noise floor" and guarantee the performance and
co-working of sensitive radio equipment.

The ARRL has clearly demonstrated the interference effects of BPL on Amateur Radio
communications, and also demonstrated strong interference from quite low power HF
transmitters into the BPL network, using BPL test sites running in the U.S. They
have presented a detailed submission to an FCC "Notice of Enquiry" into BPL
systems.

The ARRL has also demonstrated that laboratory measurements of radiated emissions,
and also computer modelling schemes,
do not correlate well to real world measurements.
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-03-100A1.doc All
ARRL information and technical papers are available from
http://www.arrl.org/tis/info/html/plc/. There are also a host of links to
other BPL information sites and suppliers of the technology.

The BBC is also concerned about interference to it’s short wave broadcasts,
especially as most receivers use inefficient internal
antennas and are often placed close to mains power wiring, ("Do EMC Limits protect
Broadcasting as intended", Stott, BBC R&D). New digital technologies emerging for
high fidelity streaming of HF broadcasting may mean a revival of short wave
broadcasting as a mainstream entertainment medium.

The Technology Drivers

Measurement and Control of the Power Network.

There are many reasons why Utility companies could benefit from BPL. The spot
price for electricity in peak periods can be as high as $10,000 per MWH and the
peak this winter was the highest on record. This summer is expected to be higher.
Naturally, utility companies are trying to find ways to even out peak demand,
http://www.nemmco.com.au/publications/whitebook/market.htm. Electricity generating
networks are expected to change to
reflect the service obligation that new information technologies will place on
them. In the next 15 years or so information
technology is expected to consume 50% of all power generated and in this high tech
environment power outages will not be
tolerated. Electricity supply will need to improve in availability and quality,
(voltage/frequency etc). It is also expected that the
electricity generation network will become less centralised and more distributed
as smaller "greener" generators come on-line
like wind farms, and other inter-active power generation systems where excess
power is sold back to the network. Add to this
the need for remote meter reading, the likely uptake of Kyoto protocols for carbon
emissions, and the fact that almost 10% of
all electricity is "lost", and it’s easy to see the pressure on Utilities to
gather information from deep within their network, and to
be able to control distribution and load on a micro-level. Energy management like
switching off air conditioners or heaters in low risk areas while maintaining
essential services would be preferable to a large area black-out. Spreading the
peak load and monitoring distribution would allow more efficient generation and
lower carbon emissions.

Competitive Broadband Access

Broadband access in Australia is expensive due in large part to the pricing
strategies of a few large players. Lack of true competition between cable networks
and Telstra networks has held back broadband development. BPL has the potential to
broadband local communities through established infrastructure and allow local
councils, utilities, etc. to offer competitive broadband services. TransACT in the
ACT is seen as an example of community broadband services,
http://www.transact.com.au. In many ways the move would be from Telco provided

solutions which are resistant to change, to more flexible community based
"knowledge" solutions. The BPL supporters in the US have gone as far as suggesting
BPL is a supporting technology to "Homeland Security" by providing a redundant
data network for disaster communications.

Rural Access

By allowing communities to provide local broadband access, BPL can help reduce the
digital divide between the city and the bush. Telemedicine and distance education
are two applications that would be attractive, however due to the nature of the
technology BPL would probably be restricted to around country towns rather than
remote rural properties.
The "Last mile" problem

A major problem in the roll-out of any network has always been the connection from
a local hub into the customer premises.  This is a very expensive and time
consuming part of the service provision with running of cables, drilling of holes,
pulling of wires and negotiating with property owners and strata Body Corporate's.
This has proven so difficult for cable operators that multi-story apartment blocks
are often avoided altogether. BPL provides a solution to the "last mile", as by
feeding the broadband signal down the power line there is no need to enter the
premises. The customer simply purchases a piece of equipment and plugs it in to
the power point. Ultimately this lowers the cost of broadband services.

The Standards Position
EMC Standards
In Australia, no specific standard applies to "Broadband Power Line" systems. "The
ACA currently has no mandatory
standards for PLC equipment that transmits information on frequencies above 525
kHz. Although there are no standards at
present, penalties apply in accordance with section 197 of the Radiocommunications
Act 1992 to a person or company who
knowingly or recklessly causes interference to radiocommunications services",
http://www.aca.gov.au/consumer_info/fact_sheets/industry_fact_sheets/fsi23.pdf. As
no specific standard exists, the generic
EMC standards would be applied, (AS/NZ 4251 and AS/NZ 4252). However the generic
standards are designed for point-source radiators where the radiation is limited
to a very small geographic area.  Distributed radiation systems, such as the leaky
power lines of the BPL system, have a much more harmful effect by creating
interference over extremely large (city wide) areas. This interference is
continuous and cannot be easily avoided by changing receiver location, (such as
moving a vehicle).
As the C-tick is the basis for all Australian telecommunications regulation any
equipment must carry a C-tick, effectively tying PBL systems into the standards
environment. There is a suggestion that the generic emission standards need to be
relaxed in order to take into account BPL, or at least a specific category within
the standard made for BPL which allows higher emission than other applications.
However the standards have been through an extensive public consultation process
worldwide, and assembled wise men and women have determined that these emission
levels provide balance between competing needs. It is the central plank of the
"compatibility levels" concept that is the engineering basis for all of the EMC
emission / immunity standards. The full story is in the basic CISPR documentation.

Ron Jackson from Zener Electric thinks BPL could be a good thing... "as long as it
complies with the generic emission
standards. Even if there comes to be a specific BPL standard, the limits would
essentially be at the generic (domestic) levels
simply because the applications are so universal. However, if the limits are to be
higher that the generic emission limits, then on
the grounds of compatibility, not to mention of fairness, it would be reasonable,
perhaps essential, to raise the limits for
everything. Such a wholesale change has enormous implications for the global
electrical industry and all of a sudden, it turns into
a world trade issue. To just take the situation within Europe, a large part of the
CE mark process is aimed directly at removing
non tariff barriers to trade between member states". The IARU plans to participate
in International Telecommunication Union
Radiocommunication Sector (ITU-R) study group sessions concerning the interference
potential of high data rate
telecommunication systems using power lines- BPL.
http://www.iaru-r1.org/news-02feb03.html
Inter-working Standards
There is currently no standard for the interworking of PLC/BPL systems. Currently
if `Home-Plug’ is installed in a situation where there is a BPL service the two
systems will clash and may prevent operation of each. There is work being done on
developing a set of interworking standards for PLC systems. There is also no
standard for the connection of different supply grids running BPL.

Where Does Fibre End and BPL Start?

BPL networks consist of a backbone fibre network ring that is connected through a
node to the medium voltage or low voltage
power lines, which then take the BPL signal to the customer. A critical question
in the design of a BPL network from a financial
and also an interference point of view is: how deep into the network does the
fibre go? The closer the fibre goes to the
customer, the less is the power required to provide an adequate signal, and one
would suppose the less interference radiated,
(this needs to be measured and confirmed). Deep fibre systems would also allow
greater bandwidth and data speeds as
required by the new technologies such as video on demand or MPEG4. However taking
the fibre to the curb or the closest
power pole is also more expensive than say to the closest medium voltage to low
voltage transformer, and slower to roll-out. In
a risky business environment where "owning the customer" is paramount importance
it’s likely that utility companies will attempt
to use the quickest and cheapest technology to get started, and then take the
fibre deeper into the network as customer numbers, revenue, and applications grow.

The Case Against PBL

Apart from the obvious cross-interference problems and the lack of appropriate
standards regulation, there are other problems
with BPL. In many ways the proposed BPL system is a dinosaur. In today’s society
the need is for faster data allowing the new
digital formats such as MP4 and Video-on-Demand to be transferred quickly.
Traditional multi-drop cable and BPL systems are built on 1960’s cable
architecture and will not provide sufficient bandwidth to each home for tomorrow’s
applications.  Rather a deep fibre network with a minimum of homes connected to
each node will be required. For these reasons the "window of opportunity" for
deployment of BPL systems’ is quite narrow.

Graham Wilson of Silicon Harbour Technologies believes the solution to the `last
mile’ problem may be a DIY solution where
customers arrange for their own fibre or twisted pair connection to the curb-side
fibre network. As there is no electrical safety
problem with fibre technology this is a possibility, and would provide the highest
bandwidth into the home. Fibre can be strung
along the existing poles, wrapped around live wires, or woven into the neutral
conductor on high voltage power lines, and has very little visual impact. TransACT
is already providing a deep fibre service in the ACT.  Due to the transmission
losses involved BPL systems would probably not be effective in providing broadband
access to very remote areas and do nothing to address the inequity of access to
broadband services for the outback, where satellite systems will provide the only
viable alternative. Long high voltage earth return distribution lines, as used in
remote Australia, are more akin to a terminated long wire antenna than an RF
transmission line. The service would mainly be delivered to those already well
served by conventional broadband cable, ADSL networks, or point to multi-point
microwave in cities, or to localised areas around country towns. Telstra
Countrywide is working to provide broadband access in rural Australia.

Australia is a country that relies more heavily on HF radio than most. Our
military, civilian, and emergency communications
systems rely heavily on HF radio, and the Over The Horizon Radar System processes
very weak signals indeed. BPL
technology needs to be very carefully evaluated in this light. The real problem is
that BPL is one of those things that "can be
shown to work" at the trial stage and if the users "get hooked", its very
difficult to terminate such a system, no matter how poor
it is in reality.

A Sociologists View:

"Technological Determinism" is a sociological term given to the concept that
technology is a driving force for social change, and
that technology sets the conditions for the operation of the political system.
Some believe it, some don’t. Marx would say that
technology establishes a particular set of power relationships. Technology shapes
politics and politics shapes technology – both
are interdependent. The chairman of the FCC, Michael Powell, is a fan of BPL as a
third broadband pipe into the home and for
it’s potential to open up more competition. "the commissions goal must be to
achieve the greatest amount of bandwidth for the
greatest number of people". This opening up of competition and increasing citizens
access to broadband services is a far more
important issue for governments than interference to a few HF users. Certainly, as
there is Ministerial interest in the technology
in Australia, BPL must be taken as a serious contender here also. For Radio
Amateurs this means that BPL will effect them no-matter what, and the extent to
which Amateurs play a pro-active role will determine their own future. When German
radio amateurs opposed the introduction of BPL the reaction of their Government
was that only 80,000 radio amateurs, (of which only about 30,000 were active),
should not be allowed to prevent the adoption of a technology which would benefit
the German population as a whole, (anecdote from Conference on Powerline
Broadband, Sydney, Dr Juergen Bender, of Parsons Brinckerhoff Associates). Our aim
must be to demonstrate that the social benefits of yet another broadband delivery
system need to be weighed against the problems encountered by a whole range of
diverse spectrum users.

Strategy

There are two obvious ways to go: Oppose the introduction of BPL at all costs.
This seems a risky way to go considering the
strong industry and political pressure for the uptake of the technology. To oppose
the technology altogether would be to close
the door on any possible negotiation, and drive information from trials
underground away from public view. To me, this seems
to be the position the ARRL has taken. OR Participate in the dialogue surrounding
BPL with a view to influencing standards
and regulation development. This seems to me like a more realistic approach. In
many ways the ACA is the key to the
interference problems with BPL. By arguing for regulation requiring a deep fibre
network with low injected power, and
orthogonal frequency-division multiplexing modulation, the interference problems
should be minimised, (however this needs to
be confirmed with real life measurements under various data conditions).

For many reasons amateurs should NOT attempt to go this alone. We need to form an
association with other MF/HF/low VHF users to put a united voice opposing radio
`smog’. Other like-minded groups are defence, safety, CB operators, 4WD groups,
broadcast band and shortwave broadcasters, aircraft operators, etc. We Should
Attend all BPL conferences and meetings and voice technical concerns. Form a new
association of concerned spectrum users, hold regular meetings, and lobby the ACA
and government agencies. Approach Australian Standards Committee TE/3 to consider
the impact of BPL on the Australian and worldwide EMC standards framework. Review
all available documentation and prepare technical responses.  Participate in all
trials and measure emission levels. Refer ARRL technical papers to IEC emission
limits.

Summary

BPL is a technology in the very early stages of adoption. PBL is a dinosaur
technology which if adopted has the capacity to cause very high levels of HF and
low VHF noise interference. Many organisations in many countries have demonstrated
the adverse effects of BPL interference on HF and low VHF communications. There is
a wide body of information both technical and anecdotal. The interference works
both ways. Low power HF transmitters have been demonstrated to interfere with BPL
networks. There will be many agencies, companies, broadcasters, and individuals
adversely affected by the introduction of BPL. There is no existing ACA
telecommunications or EMC standard specific for BPL. The appropriate standards are
the generic EMC emission standards.

There is pressure to relax generic emission standards, which has implications for
the entire electronics industry. There are better
ways to provide competitive bandwidth. BPL, as it is likely to be introduced, will
not meet the bandwidth requirements of the
new information formats such as MP4 or Video-on-Demand. BPL is a very attractive
technology to power utility companies
allowing energy management and control of the distribution system as well as
increased revenue from broadband services. PBL
increases competition in broadband services and provides broadband services in
towns not currently serviced by the Telco’s at low start-up costs. Amateurs must
be involved in the BPL standards and regulation process. This is best done from
within an alliance of other affected organisations and individuals. The deep fibre
systems (fibre to the curb) using orthogonal frequency-division multiplexing
modulation are likely to have the least potential for HF interference.
Australian Communications Authority position as of 11 September 2003
as taken from ACA website.

Note: "The ACA currently has no mandatory standards for PLC equipment that
transmits information on frequencies above
525 kHz. Although there are no standards at present, penalties apply in accordance
with section 197 of the
Radiocommunications Act 1992 to a person or company who knowingly or recklessly
causes interference to
radiocommunications services." Industry fact sheet: EMC requirements for powerline
communications equipment. Powerline
communications (PLC) equipment delivers voice and digital services over existing
power lines. To manage the risk of unwanted
emissions or interference by PLC equipment to radio-based services, the Australian
Communications Authority (ACA) has
recognised European and international standards to cover this type of equipment
under its electromagnetic compatibility (EMC)
regulatory arrangements. This fact sheet talks about mandatory standards for PLC
equipment intended for low voltage
installations only. The ACA at present has no mandatory standard in its EMC regime
for PLC equipment intended for high
voltage distribution systems. PLC equipment for low voltage
installations-installations connected to the general electrical mains
supply-is required to comply with one of the following standards mandated by the
ACA.

1. EN 50065-1 Signalling on low voltage electrical installations in the frequency
range 3kHz to 148.5 kHz-Part 1: General requirements, frequency bands and
electromagnetic disturbances. EN 50065-1 applies to electrical equipment using
signals in the frequency range 3 kHz to 148.5 kHz to transmit information on low
voltage electrical systems, either on the public supply system or within
installations in consumers' premises.

2. IEC 61000-3-8 Electromagnetic Compatibility (EMC) - Part 3: Limits-Section 8:
Signalling on low-voltage electrical installations -Emission levels, frequency
bands and electromagnetic disturbance levels. IEC 61000-3-8 applies to equipment
using signals in the frequency range from 3 kHz up to 525 kHz to transmit
information on low voltage electrical installations
either on the public supply system or within customers'premises. It specifies
disturbance limits in the frequency range from 3kHz up to 400 GHz. PLC equipment
comes under Compliance Level 2-the compliance level for a medium risk device. To
comply with Compliance Level 2, the supplier of the device must: 1. prepare a
description of the device; 2. make a Declaration of Conformity for the device; and
3. demonstrate conformity with the applicable standard by testing or technical
assessment.  In-house testing will be acceptable for this compliance level.

Please note: the ACA currently has no mandatory standards for PLC equipment that
transmits information on frequencies above 525 kHz. Although there are no
standards at present, penalties apply in accordance with section 197 of the
Radiocommunications Act 1992 to a person or company who knowingly or recklessly
causes interference to radiocommunications services.

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