Performance analysis of spectrum management technique by using cognitive radio

Recently, the shortage of assignable radio spectrums became a serious issue because of the coexistence of many licensed wireless communications systems. Therefore, cognitive radio technology has gained much attention around the world, which may be aware of its environment and makes occupancy of radio spectrums more efficient. In this paper, the frequency band between 3.4 - 4.8 GHz is focused. We consider coexistence environment of primary systems, e.g. 4th generation mobile cellular system (4G), TV broadcasting and cognitive radio system, e.g. ultra wideband (UWB) systems. UWB systems are required to have detect and avoid (DAA) technique which can detect the signals from primary systems and avoid the interference from them. We introduce two important benchmarks. Computer simulations have been performed to confirm these analytical results. In addition, the design issue of cognitive radio systems is discussed based on these numerical results. Moreover, we discuss the detection technique of primary system signals for UWB radio system with DAA and the the performance of the UWB radio system using DAA via computer simulations.