Improved cooperative spectrum sensing using belief propagation algorithm and energy detection

In this paper, we describe a new method for improving cooperative spectrum sensing in cognitive radio. We introduce a new block based on belief propagation algorithm in the conventional structure of cooperative spectrum sensing. The belief propagation block allows propagation of correct beliefs over a network of secondary users and thus in turn improves the primary user detection. We consider the network of secondary users as Tanner graph [1] and propose a scheme based on belief propagation over these graphs to improve the local decisions at the secondary users before sending the decisions to the fusion center. We demonstrate the improvement in probability of detection, P_d using our belief propagation block by simulating the performance of cooperative spectrum sensing using energy detection over Rayleigh fading channels. The proposed scheme provides improvement over conventional cooperative spectrum sensing for both soft combination and hard combination schemes.