Extending IEEE 802.22 Standard from Rural to Urban Applications

The usage of licensed television spectrum by unlicensed user to improve spectrum utilisation has been described by the IEEE 802.22 standard which seeks to use cognitive radios for wireless regional area networks. This standard is meant for usage in the rural areas where there is low usage of the TV spectrum. To make this standard available for use in the urban areas where there is greater usage of the TV spectrum; a new spectrum utilisation technique for cognitive radios is developed. This method uses the principle of matched filtering for spectrum sensing and interference temperature management for interference control against the licensed user. In the system modelling, cognitive radio access point transmits with the maximum transmission power of 36dBm when there is absence of television signal but has to compute the appropriate transmission power which is determined by the strength of the television signal present. Simulation of the developed method was done using Java programming language. In the presence of different licensed signal levels of -34.80dBm, -14.80dBm and -7.81dBm, the developed method achieved a distance of 150m, 1.5km and 3.5km respectively at 66MHz, a capacity of 789Kb/s, and a spectral efficiency of 0.045b/s/Hz.. This developed method therefore gives improved spectrum utilisation in areas where there is higher usage of the limited spectrum.