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 because 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.
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.
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
separate 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.
