Ofcom is exploring the potential for supplying rural broadband over FM radio waves freed-up by the switch from analogue to digital radio in the UK, which is expected in 2015.

This follows the recent trial project announced by a consortium of technology and media companies, including Microsoft, BT and the BBC, to use unused TV spectrum for WiFi services in Cambridge.

The telecoms regulator said that white space devices could be used to identify radio white spaces to transmit and receive wireless signals. They could then be used to deliver applications such as mobile broadband via the unused FM frequencies.

The digital radio switch-over is expected to release up to 50 percent of the capacity that is currently used to deliver FM radio services.

Ofcom chief executive Ed Richards said: “Spectrum is a resource that is in huge demand, fuelled by the recent explosion in smart phones and other wireless technologies. However there is only a limited amount of it to go around, which means we need to start thinking more creatively about how it is used. White space devices could offer the creative solution we are looking for.”

White space devices are being designed to use a wider range of frequencies than other forms of wireless technology, such as WiFi and Bluetooth. This includes the lower frequencies that were traditionally reserved for TV and radio.

At these frequencies signals are able to travel further and more easily through walls, which means they could be used to provide wireless broadband in rural areas, where it is costly to lay down the necessary infrastructure for broadband.

Ofcom has been working to develop a system where the devices can operate without interfering with other spectrum users. The devices do so by consulting a ‘geolocation database’ that provides real-time information about which frequencies are free to use at their particular location. So far, Ofcom has focused on using the white spaces between digital TV channels, but it said that this technology could be expanded to the FM bandwidth.

Last month, BT, with partners including the BBC and the University of Strathclyde, started trialling the use of TV spectrum white space for the provision of wireless broadband to the Scottish Isle of Bute.

It described initial results of the trial as “promising”, according to The Telegraph. If successful, the technology could be extended to other rural areas.