Ofcom commissions study on location where GPS is unavailable

Ofcom has appointed Quotient Associates in partnership with Shadow Creek Consulting to look into  "methods for locating wireless devices in areas where GPS is unavailable" . This is an important area of study for Ofcom as new wireless devices such as femtocell access points and cognitive radio systems begin to come into the market . Both these systems are designed to increase efficiency by re-using spectrum in a way that avoids interference with other users.

Femtocells are low power, short range, low cost base stations for 3G cellular radio systems. They will provide private coverage within a home or small office and will connect to one of the mobile operator networks via consumer grade ADSL broadband access networks. The femtocell will enable voice and data connections to the user in the normal way, whilst not placing any load on the normal cellular network.  Femtocell access points use the operator’s spectrum as used for the macro layer (although not necessarily the same local frequency). Femtocell access points are expected to be consumer devices, sold direct to the public. 

Cognitive radio systems will be designed to make secondary use of spectrum that is allocated to a primary user, where that spectrum is unused at a given time and place. Currently, TV broadcast spectrum presents a significant opportunity to allow local systems to operate in areas where TV sets will normally be tuned to another frequency, so that no interference should arise.  Such free channels may be available on a temporary basis or on a geographically restricted basis.  In other words, if the primary user (TV broadcaster) requires the channel or the cognitive device has moved areas, then the cognitive device must seek a new channel to use.

Cognitive devices and femtocells might thus both benefit from being able to establish their location. In the case of cognitive devices, a proposal being considered by Ofcom is that cognitive devices should locate their position and then consult a database to determine which channels are free in that location. In the case of femtocells, operators require that they locate themselves to avoid interfering with other spectrum users. This is especially important if femtocells are moved between locations or to different countries where their use might be illegal.  However, both of these devices are likely to be used indoors for much of the time. Typically indoor devices are unable to acquire GPS signals.

Over the next few months, input will be sought from stakeholders in the wireless device area.  To register your interest, please contact [email protected].