A novel multi-bit decision adaptive cooperative spectrum sensing algorithm based on trust valuations in cognitive OFDM system

Cognitive radio has outstanding advantages in solving scarcity of spectrum resource and low utilization rate of spectrum in current wireless communication. Spectrum sensing method in multi-bit decision model can effectively improve the detection performance when comparing with the conventional 1- bit decision model. Aiming at the actual scenarios that there may exist malicious users in the network, this paper proposes a multi- bit decision adaptive cooperative spectrum sensing algorithm based on trust valuations. In this algorithm, each cognitive user firstly makes local decision, and then the fusion center proceeds weighted fusion and makes the final decision. Moreover, the increment of each cognitive user's trust valuation is obtained according to the difference between its local decision and all cognitive nodes' weighted average decision results, and then to update each cognitive user's trust valuation. Furthermore, the weighted coefficient for the next detection using each cognitive user's trust valuation is obtained. The simulation results show that the system performance of detection probability, the system false dismissal probability and the system error probability can be improved. And the proposed algorithm can effectively improve the detection performance when there existing individual malicious users, especially to the system false alarm probability is constant.