Bell Labs' DSL could reshape broadband environment

Traditional DSL residential networks could get 300Mbit/s boost courtesy of Bell Labs

World research leader Bell Labs has successfully achieved downlink transmission speeds of 300Mbit/s over standard copper cabling at distances of up to 400 metres. In comparison, BT is still upgrading its copper network to achieve download speeds of 24Mbit/s.

Even at a kilometre away, the Bell Labs' test registered 100Mbit/s over standard digital subscriber line (DSL) links, which form the basis of UK residential broadband network connections running over copper.

One downside of the technology is that two DSL lines are required, and need to be aggregated, or in industry parlance 'bonded'. This is an ADSL2+ feature, where the two physical links run as though they were one faster link.

However, most residential links have only DSL line on the premises, and would require a 'man-in-a-van' to install an extra DSL line, which customers might be unwilling to pay for.

Currently, BT is upgrading its copper network, and is just starting to roll out optical fibre 'superfast broadband', at selected exchanges. However BT's service, like other ISPs' services based on standard copper, still uses only one DSL line.

Bell Labs' parent company, Alcatel-Lucent, said: "At its core, the technology uses DSL 'Phantom Mode', which involves the creation of a virtual or 'phantom' channel using 'bonded' DSL lines to supplement the two physical channels."

The company's head of research, Gee Rittenhouse, said: "This is prime example of the role innovation can play in adding value to existing solutions."

If the technology can be rolled out quickly, Digital Britain's aim to reach 90 per cent of the UK population by 2012 could be given a significant boost.

However, Alcatel-Lucent added that further research was underway to refine deployment models, and also determine which customer premises equipment (CPE) would be compatible with the DSL Phantom Mode technology.

In this context, CPE relates to the digital subscriber line access modules which ISPs use in telephone exchanges to deliver standard broadband over residential copper connections.

Money saved by not rolling out optical fibre to regions where this upgrade was possible could be used to roll out optical fibre to rural areas far away from phone exchanges.

Ovum analyst Kamalini Ganguly said that this added a new dimension to the debate about rolling out faster broadband able to achieve 100Mbit/s.

"That existing copper loops can be used to achieve 300Mbit/s at 400 metres reshapes the whole next-generation broadband competitive environment," said Ganguly.

"It will open up a wide range of new business opportunities for ‘traditional’ DSL players," he added.