Deflection coefficient maximization criterion based optimal cooperative spectrum sensing

This paper proposes an optimal cooperative spectrum sensing scheme, based on the criterion of deflection coefficient maximization of the global decision statistic. Multiple cooperative secondary users serve in the cognitive radio network to provide space diversity for spectrum sensing. After the fusion center acquires the optimal fusion weights, an optimal global threshold setting strategy is utilized to obtain the final global decision. Since the proposed optimal cooperative sensing scheme requires precise estimations of primary user signal strengths and the noise variances at different cooperative secondary users, a recursive estimate algorithm is also proposed. Simulations illustrate the proposed optimal soft fusion scheme can significantly improve the spectrum sensing performance and outperform the conventional maximal-ratio combining and equal gain combining schemes. The recursive estimate algorithm can effectively approach the ideal performance of the proposed sensing scheme.