Ofcom Looking Into White Space Technology For Wireless Broadband

Ofcom White Space Technology Consultation

Communications watchdog Ofcom has today launched a new consultation to look into the regulatory and technical issues involved in “white space technology”, which is expected to be available by the end of 2011.

White space technology refers to the equipment that could be used in order to provide wireless broadband in the spectrum that is currently used for television signals, between 500MHz and 800MHz, where space is left between channels to counter interference.

Ofcom’s director of technology resources, Professor William Webb, noted that “that the white space could be used for several new technologies and broadband situations.”

“The airwaves that wireless devices depend on are becoming increasingly congested. We need to think about more efficient ways of using this limited resource. Using the white spaces between TV channels is a good example of how we can both use spectrum more efficiently and provide opportunities for innovative new applications and services.

Our role is to encourage innovation rather than decide on what technology and applications should succeed. To that end, we hope that these frequencies, which offer improved signal reliability, capacity, and range over existing wireless technologies, will bring clear benefits for consumers.”

Ofcom believe that they key to making the technology work is to incorporate a system that searches for unused space between the television stations, and then to use that space without interfering with other broadcast signals.

This consultation will examine ways in which this can be accomplished by cross-checking a “geolocation database” that contains live information about which frequencies are free at that specific location.

How does White Space Technology work?

White space technology will work in a similar way to wi-fi, which uses a wireless router to send and receive information to other wireless devices. A key difference is that the white space router will first need to consult a list of databases hosted online.

It will describe its location and device characteristics to one of these databases on a regular basis. The database will then return details of the frequencies and power levels it is allowed to use.

Standard wi-fi is limited to an area of 100m, however the lower frequency signals in the white space can travel from between 500m and 600m, depending on conditions and location, with the potential to reach much further in more rural areas.

“In rural deployments, where the transmitter is placed on a large mast and is directional, there have been trials with a range of many miles,” Webb said. “There’s still a lot to learn – such as whether you would need an external antenna – but this is certainly promising as a rural broadband solution.”