Ofcom, the UK communications regulator, has started the process of considering what to do with the airwaves released by the transition to digital television.

The radio spectrum is a finite national asset, with the five analogue terrestrial channels in the UK using nearly half the most valuable frequency bands below 1GHz, based on a plan originally prepared in the late 1950s.

The Digital Dividend Review will consider the potential for a large amount of the frequency spectrum currently used for analogue broadcasting to be released for new services after the digital switchover that will take place between 2008 and 2012.

“This is a particularly large and valuable piece of spectrum,” said Stephen Carter, the chief executive of Ofcom. “The benefits of a digital switchover, in terms of efficient use of spectrum and subsequent innovation, are becoming clearer.”

The frequency range 470-854MHz is conventionally partitioned into 84 channels of 8MHz each.

Ofcom estimates that up to 14 channels or 112MHz of spectrum will be completely released by digital switchover. This UHF spectrum offers a technically valuable combination of capacity and coverage.

Possible uses include new mobile services, wireless broadband, new broadcast services, and additional channels, including high-definition television.

Of the 32 channels assigned to digital terrestrial television, only six will be used at any one site. Unused channels at each site may be available for other uses in an interleaved pattern.

Ofcom estimates that 14 channels or 208MHz of such ‘interleaved’ spectrum will be made available. This is currently used for programme making and special events, including outside broadcasts.

Ofcom will seek to adopt a market-led approach to the allocation of spectrum. It warns that there may need to be changes to licences held by broadcasters under the Wireless Telegraphy Act, and in some cases new licences will need to be issued.

Over the next year Ofcom will assess how the cleared spectrum should best be made available for use, and will start to develop models for auctioning and allocating that capacity.

In the meantime, the regulator is inviting proposals on the use of the spectrum, which is likely to lead to lobbying by groups with particular interests, not least from those wanting to launch mobile or high-definition television services.