The original notion of cognitive devices might have been abandoned, but the UK communications regulator is actively exploring a potential new generation of white space devices, writes David Davies.
If introduced, the new devices would search for unoccupied spectrum (white spaces) between TV channels in order to transmit and receive wireless signals. Each device would consult a “geolocation database” containing live information about which frequencies are free to use at their current location, in order to avoid interference with TV broadcasts and other wireless technologies – such as those employed by the PMSE (performance making & special events) community. The device would describe its location and characteristics to a database on a regular basis, yielding information about the frequencies and power levels that it is allowed to use.
In recent years, the debate surrounding the next generation of wireless devices has revolved around the notion of so-called cognitive technology that could identify free spectrum independently, but this has now been deemed unworkable.
An Ofcom spokesperson tells PSN-e: “We have dropped the use of the term ‘cognitive devices’ because originally manufacturers had hoped it would be possible for devices to sense when a frequency was in use in a given area and switch to another. However, testing showed that the process wasn’t robust enough. This is why some people were – quite rightly – concerned about interference. We aren’t willing to approve any technology that carries such a risk.
“Where a database is used the device is not exhibiting intelligent or cognitive behaviour but merely responding to the information received from the database.”
With a view to making it possible for interested companies to host geolocation databases in 2011, Ofcom is holding a new consultation, the full details of which can be found here. The closing date for responses is 7 December.