Nortel Networks has launched a collaboration with WiMax service provider Urban Wimax and others, to demonstrate mobile WiMax in the UK, using the IEEE 802.16e standard, in advance of Ofcom's likely auction of 2.5GHz spectrum in 2008.

Fixed WiMax services are becoming commercially available through companies like Urban WiMax, but mobile WiMax services have yet to arrive, despite the big plans of Sprint Nextel and Clearwire who, last week, teamed up to provide US coverage.

Nortel and Urban will construct and demonstrate a "user-ready" mobile WiMax service, using access to up to 9000 rooftops provided by Macropolitan, a company that organises base station access, and handsets and client equipment provided by LG, to convince Ofcom and operators that the technology is ready.

"If the UK is to remain competitive in the digital economy it must improve broadband connectivity, both in terms of penetration and bandwidth," said Sasha Williamson, chief executive of Urban Wimax. "4G WiMax is the most economical way of achieving this and, with the 2.5/2.69GHz spectrum becoming available next year, the collaboration will be in prime position to deliver a premier wireless broadband service to business and consumer users in the UK."

The demonstration network will provide 40Mbit/s from each base station, shared between users, so typically one user could get 5 Mbit/s depending on the number of people using the service, and their distance from the base station. The demonstration network will show how WiMax could be used by different market segments, said the group, which demonstrated trans-Atlantic voice and video calls on Friday, linking the UK, Canada and the US.

Mobile WiMax is the natural 4G network, says the group, because it has a greater range than Wi-Fi and, compared to existing 3G mobile networks, can provide higher bandwidth at less than half the cost.

The 2.6GHz band was once earmarked to extend existing 3G networks, but Ofcom has consulted and will be auctioning the spectrum in 2008. Ofcom makes its licences "technology neutral" so the licence holder can decide what to do with the spectrum.

However, the group is concerned that big providers of traditional networks may buy up all the spectrum, or that Ofcom may get cold feet and let the auction date slip: "This may appear to be a long way off, but we have to move now," said Williamson, who warned that Britain is dropping down the international rankings for provision of fixed and mobile services.

The demonstration took place five years to the day before the opening of the London Olympics, an event where he says WiMax networks could be very useful.