Google's home is in Mountain View, California

Google is pressing the US government to allow the unlicensed frequencies of TV "white space" to be used for wi-fi.

The firm has written an open letter to regulators saying the US spectrum was a "once in a lifetime opportunity".

White space is unused blocks of frequencies in-between channels broadcast on analogue airwaves.

"The vast majority of viable spectrum in this country simply goes unused, or else is grossly underutilised," wrote Google's Richard Whitt in the letter.

"Unlike other natural resources, there is no benefit to allowing this spectrum to lie fallow," he added.

Google has said the white space could be used to bring "ubiquitous wireless broadband access to all Americans".

In the past TV broadcasters have opposed the use of white space, fearing it would cause interference with television programming.

Google believes the spectrum could create a wi-fi dividend

But in its letter, Google urged the FCC to adopt a series of overlapping technologies, including "spectrum sensing," designed to prevent signals from interfering with each other.

Mr Whitt said there was enough unused spectrum for businesses to create a wide range of options, such as building small peer-to-peer networks or even establishing an alternative national wireless network.

Google has said that devices designed to take advantage of the white space spectrum could be on the market by the end of 2009.

Other countries are also looking at using white space spectrum.

In the UK much of this space is being dedicated for use by services like wireless microphones for broadcast use, and for cognitive radio, a smart wireless technology that allows for the use of wi-fi.





