Use of 'white spaces' sanctioned for delivering wireless data services in the UK

Ofcom said the move was designed to help meet "the increasing demand for more spectrum to deliver existing and new services" (111-page / 4.55MB PDF). It said "commercial applications" for the use of white space technology could be operational before the end of this year.

Businesses will not be required to hold a wireless telegraphy licence to make use of white space that exists in the 470-790MHz frequency band. However, Ofcom has outlined measures to limit the risk of new white space services interfering with existing digital terrestrial television (DTT) and programme making and special event (PMSE) services reliant on the spectrum in that band.

To address the risk, databases will store information about DTT and PMSE users of spectrum in the 470-790MHz frequency band and devices used to transmit data using the white space between the spectrum in this band will also have to adhere to "a minimum technical specification".

Ofcom said the combination of the databases and the device requirements will allow access to the spectrum by white space devices to be managed "dynamically".

"To avoid interference, databases will communicate with these devices to give them technical constraints they must operate within," Ofcom said. "These databases identify locations, frequencies and times where white space devices will not affect existing users and will apply rules, set by Ofcom, which put limits on the power levels they can operate at."

'White space' is the term used to refer to the gaps that exist between radio spectrum bands already in use. In the 470-790MHz frequency band, the white space currently acts as a buffer between the spectrum used to support DTT broadcasting and PMSE services, which include the use of wireless microphones and talkback and audio links for TV or radio programmes, in theatres or at sports events.

The use of white space wireless technology was trialled last year. Ofcom has concluded that new services can be delivered in the 470-790MHz band without it causing "harmful interference" to existing DTT and PMSE services.

However, it decided to adopt a "cautious initial approach" to the use of white space wireless technology as there remains some uncertainty as to whether new white space services can co-exist with existing DTT and PMSE on a mass scale.

"The overarching principle we have applied to setting the coexistence criteria is that we should take a cautious initial approach in order to achieve our aim of ensuring a low probability of harmful interference to existing users," Ofcom said. "There are a number of reasons for this."

"Database-controlled dynamic spectrum access is a new approach to spectrum sharing that has not yet been fully demonstrated with a high volume of users. Equipment for white space use is still largely at an early stage of development and, while there is an ETSI harmonised standard and we will specify minimum technical requirements that equipment must meet to operate in white space, we do not yet know what the actual characteristics of mass consumer white space equipment will be," it said.

"We also do not yet know what the real use cases and volumes of use will be. All this provides a high degree of uncertainty about how use of white spaces, and the market in white space devices, will develop and we therefore have taken the view that, to begin with, we need to set our protection criteria in a conservative way," the regulator said.