Communications watchdog Ofcom has officially confirmed that radio spectrum that has been reserved for TV broadcasts but is not being used can be repurposed without a licence.

Many sections of the radio bandwidth that has been traditionally reserved for TV signals are not in use. This ‘white space’ can be repurposed for a number of applications, including extended WiFi networks and machine-to-machine communications.

White space devices work by consulting a database to find out which frequencies are free to use in their location. This allows them to find spectrum that is not being used, either by TV broadcasters or by other devices, on ad hoc basis.

This would not be practical if each device had to apply for a licence to use that spectrum. Ofcom had previously indicated that it planned to allow white space devices to be unlicensed, and today confirmed that this is the case. It is now in the process of updating the relevant regulations.

Ofcom has also decided to allow multiple parties to develop alternative geolocation databases to support white space devices. This "will create a competitive marketplace and incentivise operators to provide the best database service to consumers", it said.

White space technology could be launched in the UK as soon as 2013, Ofcom commented.

Earlier this year, a consortium of companies including Microsoft and BT launched a trial in the city of Cambridge, using white space spectrum to support wireless broadband.