The unused parts of the spectrum are the bits between TV channels, which have a far greater range than the usual broadband Wi-Fi technology.
The regulator hopes that by making this white space spectrum available, rural areas will have greater access to broadband because the further reaching signals can easily zip through walls as well as the air.
Long time coming
"At an early stage Ofcom identified the potential of White Spaces, which are currently lying vacant all around us," said Ed Richards, chief executive of Ofcom.
"The solution we have devised creates the opportunity to maximise the efficient use of spectrum and open the door to the development of a new and exciting range of consumer and business applications.
"We are hoping that white space develops in the same way as Wi-Fi has in the UK.
"It offers much more capacity than Wi-Fi in homes and offices, as well as significant use in extending broadband to rural areas."
The first white space technology is anticipated to go on sale in 2013.