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.

Read more at BBC