Sensor network controlled indoor cognitive radio systems

Building structures can shield signals and reduce interference. A considerably large area may be allowed for unlicensed operations on the licensed spectrum if the operations only happen indoors. Interference to outdoor licensed users from the indoor operations can be minimised, if the unlicensed users adjust their transmit power according to their locations in the building. This paper presents a novel cognitive radio system to access the licensed spectrum inside a building which is located at an area where it is currently excluded from unlicensed operations. The system utilises an indoor sensor network to limit the interference to the outdoor users through the means of power control. A power control algorithm is also developed for the system. The performance of the system is evaluate through Monte Carlo simulation. The results show that the proposed system is able to control the outdoor interference caused by unlicensed operations from indoor users.