Seminar Report Powerline Communication 1.0.0 Introduction Connecting to the Internet is a fact of life for business, government, and most households. The lure of e-commerce, video on demand, and e-mail has brought 60 million people to the Internet. Once they get to the Internet, they find out what it’s really like. That includes long waits for popular sites, substantial waits for secure sites, and horrible video quality over the web. Telephone companies have offered high bandwidth lines for many years. For the most part, the cost of these lines and the equipment needed to access them has limited their usefulness to large businesses. The lone exception has been ISDN (Integrated Services Digital Network) which has won over some residential customers. ISDN offers fast Internet access (128k) at a relatively low cost. Dept. of EEE BMSCE, Bangalore 1
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Seminar Report Powerline Communication
1.0.0 Introduction
Connecting to the Internet is a fact of life for business,
government, and most households. The lure of e-commerce, video on
demand, and e-mail has brought 60 million people to the Internet. Once
they get to the Internet, they find out what it’s really like. That includes
long waits for popular sites, substantial waits for secure sites, and horrible
video quality over the web.
Telephone companies have offered high bandwidth lines for
many years. For the most part, the cost of these lines and the equipment
needed to access them has limited their usefulness to large businesses. The
lone exception has been ISDN (Integrated Services Digital Network) which
has won over some residential customers. ISDN offers fast Internet access
(128k) at a relatively low cost.
Here the solution is Powerline communications (or PLC).
Powerline communications is a rapidly evolving market that utilizes
electricity power lines for the high-speed transmission of data and voice
services.
None of the available Internet access services offer the right
balance of cost, convenience, and speed. Digital Powerline technology
could change all that. It gives customers high speed Internet access through
electrical networks. Lower costs are achieved because the service is
implemented on standard electrical lines. The service is also convenient
Dept. of EEE BMSCE, Bangalore1
Seminar Report Powerline Communicationbecause it’s already in your home. Internet access through Digital
Powerline would be at (at least) 1Mbps, 20 times faster than a standard
phone/modem connection.
1.1.0 History
The technology has roots going back to the 1940s.It has been
used by power utilities for simple telemetering and control of electrical
equipment in their networks.
What is new is the integration of activities outside the building
with those inside the building at a much higher bandwidth, 2.5 mbps or
higher.
1.2.0 Overview of Technology
PLC works by transmitting high frequency data signals
through the same power cable network used for carrying electricity power
to household users. Such signal cannot pass through a transformer. This
requires devices that combine the voice and data signals with the low-
voltage supply current in the local transformer stations. The signal makes
its way to neighborhoods and customers who could access either it
wirelessly, through utility poles.
Digital Powerline use a network, known as a High Frequency
Conditioned Power Network (HFCPN), to transmit data and electrical
signals. A HFCPN uses a series of Conditioning Units (CU) to filter those
Dept. of EEE BMSCE, Bangalore2
Seminar Report Powerline Communicationseparate signals. The CU sends electricity to the outlets in the home and
data signals to a communication module or "service unit". The service unit
provides multiple channels for data, voice, etc. Base station servers at local
electricity substations connect to the Internet via fiber or broadband coaxial
cable. The end result is similar to a neighborhood local area network.
1.2.1 The Server
The Digital Powerline base station is a standard rack
mountable system designed specifically for current street electricity
cabinets. Typically, one street cabinet contains twelve base station units,
each capable of communicating over 1 of 40 possible radio channels. These
units connect to the public telecommunications network at E1 or T1 speeds
over some broadband service.
Several options, with different costs, can provide broadband
Internet service to each base station. The simplest solution is connecting
leased lines to each substation. This solution is potentially quite costly
because of the number of lines involved. A wireless system has also been
suggested to connect base stations to the Internet. This option reduces local
loop fees, but increases hardware costs. Another alternative involves
running high bandwidth lines, along side electric lines, to substations.
These lines could be fiber , ATM, or broadband coaxial cable. This option
avoids local loop fees, but is beset by equipment fees. The actual
deployment of Digital Powerline will probably involve a mix of these
alternatives, optimized for cost efficiency in different areas and with
different service providers.
Dept. of EEE BMSCE, Bangalore3
Seminar Report Powerline Communication
These base stations typically serve approximately 50
customers, providing over 20 MHz of usable spectrum to near end
customers and between 6 and 10 MHz of useable spectrum to far end
customers. The server operates via IP to create a LAN type environment for
each local service area.
1.2.2 The HFCPN Conditioning Unit
The conditioning Unit (CU) for the Digital Powerline Network
is placed near the electric meter at each customer’s home. The CU uses
band pass filters to segregate the electricity and data signals, which
facilitate the link between a customer’s premise and an electricity
substation.
The CU contains three coupling ports. The device receives
aggregate input from its Network Port (NP). This aggregate input passes
through a high pass filter. Filtering allows data signals to pass to a
Communications Distribution Port (CDP) and a low pass filter sends
electric signals to the Electricity Distribution Port (EDP).
The 50 Hz signal flows from the low pass filter, out of the
EDP and to the electricity meter. The low pass filter also serves to attenuate
extraneous noise generated by electrical appliances at the customer
premises. Left unconditioned, the aggregation of this extraneous noise from
multiple homes would cause significant distortion in the network.
Dept. of EEE BMSCE, Bangalore4
Seminar Report Powerline Communication
The high pass filter facilitates two way data traffic to and from
the customer premise. Data signals flow through the CDP to the customer’s
service unit via standard coaxial cable.
1.2.3 Service Unit
The service unit is a wall or table mountable multi-purpose
data communications box. The unit facilitates data connections via BNC
connectors to cable modems and telephone connections via standard line
termination jacks. The service unit provides its own line power for ringing
and contains a battery backup in case of power outage. Alternative
Differential Pulse Code Modulation (ADPCM) is used for speech
sampling. Because Digital Powerline allows for
the termination of multiple radio signals at the
customer premises, the service unit can
facilitate various Customer Premises Equipment
(CPE) simultaneously. In a manner similar to
ISDN, data (computers) and voice (telephones)
devices can coexist without interfering with
each other.
Dept. of EEE BMSCE, Bangalore5
Seminar Report Powerline Communication
1.3.0 CASE STUDY
1.3.1 Powerline Trials: Seymour Park Primary School
Digital Powerline
technology was
first tested in a
public setting at
the Seymour Park
Primary School in
Manchester, UK.
Twelve PCs were
connected to a
single Digital Powerline outlet. Dedicated high-speed access to the Internet
turned out to be a great success in the eyes of students and teachers.
Nortel’s Digital Powerline web site quotes Seymour Head teacher, Jenny
Dunn; "The high speed connection really lets us take advantage of the
educational potential of the Internet. With a normal connection the children
could lose interest waiting for pages to download. The new system means
information arrives virtually instantaneously, thereby maximizing teaching
time and keeping children on task. This set is amazingly flexible in
educational terms, and not only gives us the additional medium with which
to improve standards, but prepares us for the National Grid for Learning."
Dept. of EEE BMSCE, Bangalore6
Seminar Report Powerline Communication
1.3.2 Powerline Trials: Stanley Road
Following the success at Seymour Park, a more
comprehensive trial was initiated at the Stanley Road electricity substation,
also located in
Manchester. The crux
of this trial was to test
the limits of
Powerline technology
and make sure that it
could meet industry
standards even in worst case scenarios.
The Stanley Road substation was set up to use two distributors
to serve two distinct neighborhoods. Northumberland Close is located 350
meters from the substation and Seymour Close is located 600 meters from
the substation. Fifteen users were chosen between the two neighborhoods
to participate in the pilot program. They received various data and
telephone services as well as remote metering/information services.
Unfortunately, the results of the trial are unobtainable. Nortel
and Nor.Web claim that the results of this trial and similar trials in the
United States are being protected for competitive reasons. The only
indication of the trial’s success is a subjective quote from Nor.Web. The
quote states that "results produced over this period have now proved
conclusively that Nor.Web’s technology provides a commercially viable
alternative to established means of telecommunications delivery to
customer premises."
Dept. of EEE BMSCE, Bangalore7
Seminar Report Powerline Communication
1.4.0 Application areas offered by Powerline communications
PLC offers end-users a broad spectrum of applications and
services including broadband Internet access, voice over IP, multimedia
services, telecommunication, home automation and energy
managemen(near energy services). Powerline offers the opportunity for
the PC to be integrated into the household as never before. As part of the
household power grid, PCs could easily be programmed to turn off lights
and control security devices.
1.4.1 Powerline telecommunication
Powerline telecommunications is a rapidly evolving market
that utilises electricity power lines for the high speed transmission of data
and voice services. The especially exciting thing about the potential for
PLT is that it holds the promise of solving the underlying structural
problem confronting the local access market today. PLT can provide the
holy-grail of a much needed, highly elusive, alternative source of
ubiquitous local loops other than the incumbent telco operator, something
we sadly have yet to see happen on a sufficient scale and scope. Indeed,
what make PLT so attractive from a public policy point of view are the
facts that:
The power grid is ubiquitous; it constitutes an existing network
infrastructure to billions of private consumers and businesses
The power grid offers last-mile conductivity
The power grid supports information based services with strong
growth potential.
Dept. of EEE BMSCE, Bangalore8
Seminar Report Powerline Communication1.4.2 Home Automation
The Home Plug Powerline Alliance (HPA), a U.S. consortium
of 90 members, including such high-tech giants as Cisco, Intel, Motorola,
and Hewlett-Packard is working on technology to link appliances such as
TVs, computers and cookers via the home electrical system.
Appliance makers like Samsung Electronics Co. have been
solidifying cooperation with their technology partners to enable them to
market Internet-controllable home appliances this year. Samsung plans to
set up a “Dream LG” site on its homepage to advertise its Internet-enabled
products to potential customers.
1.4.3 Internet access
Power line communications can also be used to interconnect
home computers, peripherals or other networked consumer peripherals.
Specifications for power line home networking have been developed by a
number of different companies within the framework of the HomePlug
Powerline Alliance, the Universal Powerline Association and the HD-PLC
Alliance.
The Intellon, its PowerPacketTM Powerline networking
chipset, the first product certified as compliant with the HPA’s 1.0
Specification . The chipset allows users to access the Internet and connect
computers and other devices at speeds up to 14 mbps by simply plugging
into power outlets throughout a home or small office.