Cooperative Spectrum Sensing in a Realistic Cognitive Radio Environment

Abstract

Cognitive Radio is a novel technology that has the potential to deal with the requirement and scarcity of the underutilized radio spectrum. A remedy to spectrum scarcity is to improve spectrum utilization by spectrum sensing where the secondary unlicensed users are allowed to access the underutilized licensed bands when the primary licensed users are inactive. Cooperative Spectrum Sensing (CSS) is done by collaboratively detecting the spectrum holes by Energy Detection technique to improve the spectrum sensing performance. In most existing contributions each Cognitive Radio reports their local sensing results to a Cognitive Base Station (CBS) for a final decision where the reporting channel is considered as an ideal error free channel. In this paper a realistic cooperative spectrum sensing network is designed where the reporting channels from the cognitive radios (CRs) to the CBS are affected by Additive White Gaussian Noise (AWGN) and Rayleigh fading. To minimize the effects caused by these channel uncertainties an optimal Minimum Mean Square Error (MMSE) detector is used to improve the detection performance under realistic spectrum sensing environment. Simulation results investigating the performance degradation incurred by considering realistic reporting channels is analysed and presented in various practical scenarios.