Powerline Communications

What is powerline communications?
Powerine communications (referred to in the industry as PowerLine Communications, or PLC) is a rapidly evolving market that utilizes electricity power lines for the high-speed transmission of data and voice services.

How does powerline communications function?
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 ("outdoor devices") that combine the voice and data signals with the low-voltage supply current in the local transformer stations to bridge the last mile. In the house, "indoor devices" (adapters) are used in order to filter out the voice and data signals and to feed them to the various applications (e.g. PC/Internet, telephone, etc.).

Is powerline communications a new technology?
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 – this means voice and data transmission via the mains supply voltage network right through to every power socket in the building, as well as in the reverse direction at high speed.

What are PLC advantages?
Availability of an extensive communications infrastructure in place, thus eliminating the need for building of redundant facilities. Only the substation server equipment and customer conditioning/service units need to be installed in order to establish a digital powerline network.

Powerlines carry signals for long distances without requiring regeneration. Their near light speed propagation makes them very powerful for fast delivery of video and audio data. There is no topology limitation for powerlines.

High transmission rate, right now 3 mbps in uploading and downloading. Sumitomo Electric Industries, Ltd. developed high speed PLC modems, whose data transmission rate is 45 mbps, several times higher than ADSL. The data transmission rate is expected up to 200 mbps in the future by improving the PLC chip.

Permanent on-line connection with the potential for lower charges.

No need for complicated wiring and additional installations. Move your computers and appliances where you want.

Secure data-encryption.

Lower investment costs compared to those envisaged for other broadband data access systems.

Electric companies could offer a broader bundle of services then telecom providers.

What are PLC weaknesses?
Powerline solutions, like phoneline solutions, are unintentional radiators. Emissions can potentially cause interference with radio, television, community antenna television, telephone and DSL services.

Data signal disruption due to noise interference and signal loss over longer distances.

Problems with bypassing transformers.

From a market perspective, powerline networking technology faces potentially serious competition from wireless local area network (WLAN) solutions.

Providers would still need to come up with with a “last mile” solution for hooking up individual subscribers to the neighborhood transformer. That connection could be through cable or phone lines, or wireless.

Powerline's maximum access speed is shared with all users connected to the same local network station. The more people that are simultaneously on the Internet, the lower the speed obtained.

The technology is still in the developmental stage.

Who is testing or has tested the technology?
PLC abroad
Proof that the PLC concept works in practice was furnished by a series of field trials by Main.net of Israel, Ascom of Switzerland and some other companies in 16 European countries from Portugal to Scandinavia, as well as in Hong Kong, Korea, India, Singapore and the Americas. These trials fulfilled all expectations of reliability, functionality and the practical applications of powerline communications. The first installations are now already up and running or about to go live.

Users in Germany include the electricity companies RWE Energie Essen and EnBW Energie Baden-Württemberg, while in Spain the energy and telecoms group Endesa uses PLC technology. Lina.Net of Iceland, a subsidiary of Reykjavik Energy, has recently begun introducing PLC technology with the declared objective of providing private households with fast Internet access over the power grid rather than the telephone network. In Sweden Sydkraft, one of the leading energy providers in Scandinavia, uses PLC for bridging the last mile as well as for networking inside buildings.

PLC in USA
New York-based Ambient - which will partner with Cisco, perhaps the technology's largest supporter, and Bechtel on future projects - is working with the utility Consolidated Edison of New York and Southern Telecom of Atlanta, a subsidiary of Southern Co., a leading energy company to expand its testing to several hundred homes. Results indicated that high frequency data transmissions could be transmitted and received over distances of more than half a mile, with minimal signal loss. In recent months, Ambient has achieved throughput speeds in excess of 20 mbps, and connectivity over distances of 1.5 miles. Up to 200 users can be supported on a single distribution circuit. Pricing for the systems is not yet available. Ambient expects to go fully commercial with its systems by first quarter 2003.

Powerline Technologies in Reston, Virginia, is trying out its system with two utilities in the East and one in the Midwest. Earlier last year, the company finished initial PLT tests in suburban Atlanta, where a handful of households accessed the Net through a specially designed modem that can hit speeds greater than 1.5 mbps.

Owing to recent advances for PLC in Europe, and the efforts of a handful of U.S. PLC vendors – including one backed by American Electric Power (AEP), PLC is closer to being a commercial reality in the U.S. than ever before. Beta tests scheduled by each of these firms over the next 12 months will be crucial to resolving outstanding technical hurdles, standardizing equipment and deployment techniques, and building interest and partnerships with utilities.

What application areas are offered by powerline communications?
PLC offers end-users a broad spectrum of applications and services including broadband Internet access, voice over IP, multimedia services, home automation and energy management. 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. The Homeplug Powerline Alliance (HPA), a U.S. consortium of 90 members, including such high-tech giants as Cisco, Intel, Motorola, and Hwelett-Packard is working on technology to link appliances such as TVs, computers and cookers via the home electrical system.

Last December Intellon announced its PowerPacketTM powerline networking chipset, the first product certified as compliant with the HPA’s 1.0 Specification introduced earlier that year. 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.

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.

More about powerline communications:
Overview and some technical aspects of PLC

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