Energy Detection based Cooperative Spectrum Sensing and Performance analysis for Soft and Hard Combination Techniques in Cognitive Radio Networks

This paper focuses on spectrum sensing in cognitive radio (CR) which is a recently introduced technology in order to increase the efficiency of spectrum utilization. Increasing efficiency of the spectrum usage is an urgent need as an intrinsic result of the increasing demand for higher data rates, better quality of services and higher capacity. There are several spectrum sensing techniques proposed in literature for CR based systems like non cooperative and cooperative spectrum sensing. In this paper, energy detection based cooperative spectrum sensing approaches and its various forms, soft combination techniques such as MRC, EGC, OC, SC, SLS, SLC and hard combination methods consist of AND, OR and MAJORITY for CRs with and without multiple antenna are examined and comparative performance results are obtained in fading channels. We consider the most common multiple antenna processing methods and analyze their detection performance based on the achieved probability of detection for a pre-specified probability of false alarm and given signal-to-noise ratio. Simulations results show that the EGC and MRC achieve the highest gain and multiple cooperating users increase diversity by providing multiple measurements of the signal and thus guarantees better performance at low SNR.