Power lines just right for fast access

By CHRIS BARTON

If power line communication is feasible, you have to wonder why it's not switching on here.

The technology has proved electric in Germany thanks to RWE Powerline which began testing internet access through power wires to 200 households in Essen in May 2000.

The service, an offshoot of Germany's biggest power utility, went live commercially in Essen and Muelheim in July 2001, providing 2 megabits per second (Mbps) down the line.

Power line communications (PLC) works by transmitting data signals through the same power cables that transmit electricity, but using a different frequency.

To do this, every PC needs to be attached with a PLC adaptor, which also functions as a modem.

While the modems in Germany are operating at 2Mbps, newer modems - including those on trial at UnitedNetworks on the North Shore - have a maximum speed of 45Mbps over a distance of about 400 metres.

To PLC-enable its power grid, the utility company has to install an outdoor master device at the power substation or transformer which is in turn connected to the internet backbone using fibre or other technologies. To gain access to the internet, users simply connect their computers to a wall power plug socket via a PLC modem which feeds out through the building wiring and on to the street power lines.

That makes PLC a very viable alternative to the Telecom wire that holds the monopoly on communications to our homes - also known as the "local loop" or "last mile".

It should be pointed out, however, that PLC is a point-to-multipoint technology - which means the 45Mbps needs to be shared by users in a building or within an area. Typically a transformer feeds around 50 homes, so that would mean about 0.9Mbps each if all the homes were on the net at the same time.

Using existing building wiring as a ready-made networking wire is well established in the United States. The HomePlug Powerline Alliance, an industry consortium based in San Ramon, completed its first technical standard late last year.

First generation HomePlug adapters plugged into computers and then your power outlet can move data through the wiring in your walls to other computers in your house as fast as 14Mbps.

There are at present two main PLC equipment providers - Switzerland's Ascom and Israel's Main.net.

As well as Germany, PLC services are underway in Sweden, Singapore and Austria.

So what's the holdup here? In April Buller Electricity began testing 2Mbps technology for a planned introduction to Westport. And in June UnitedNetworks said it was testing the technology to homes on the North Shore. But so far no one has announced a commercial service.

Some of the problem may lie with the Electricity Act, which says that electricity operators have no authority to sell communications services off their lines. To do that they need to become a telecommunications operator.

The situation gets more difficult when power lines and poles are on private land. If the lines and poles are used for anything other than carrying electricity, then consent from the landowner is required.

The potential stumbling block has been highlighted by Transpower, which is investigating the feasibility of stringing fibre and co-siting wireless transmitters on its pylons.

But unlike the Telecommunications Act, which requires that all equipment attached to the network be tele-permitted, there is no provision in the Electricity Act to stop people attaching PLC equipment to power lines from their homes.

That raises the startling possibility of one house in a neighbourhood installing a satellite dish to receive broadband internet and then sharing that link with the neighbours via PLC modems feeding out over the local power lines.

The scenario is painted by John Rutherford of Power Line Communications, which was involved in the UnitedNetworks trial.

He holds a powerful patent card - No 235810 - which appears to indicate anyone involved in PLC needs to talk to him first.

The patent is for a system which "provides communication services to the neighbourhood community through individual cables by telecommunications as well as by radio communications".

According to Rutherford, it relates to bringing data or communications to an unmanned location - such as a satellite dish, wireless antenna or transformer - processing the communications there and then distributing them to the equipment of the nearby community.

It's a method he has used in the multi-channel TV systems operated in Gisborne by Civic Enterprises.

The system involves placing a dish on the back corner of one property in each housing block and distributing the incoming signals to the houses in the block via the backyards instead of coming in from the streets as in a conventional TV cable system.

But Rutherford's favoured scenario is to work with lines companies and develop a hybrid satellite-PLC system whereby satellite dishes near transformers provide links to the internet backbone and power lines the connection to homes and businesses.

He also thinks it would be a great way to provide affordable broadband to schools - a proposal he plans to put forward to the Government's Probe project.

But so far no one is buying, which is a shame because the technology could break Telecom's stranglehold on the local loop and at last bring competition to a marketplace where it has been sorely lacking.

* Email Chris Barton

RWE Powerline

HomePlug Powerline Alliance

Ascom

Main.net

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