A Spectrum Sensing and Congestion Control Strategy for Distributed Cognitive Radio System

Cooperative spectrum sensing is one of the widely used spectrum sensing methods in cognitive radio systems, which can increase the spectrum sensing quality by leveraging the diversity of multiple secondary users. However, in distributed communication system, there are no effective central controller and cooperative strategy, and most secondary users are likely to overhearing others’ sensing results other than contributing to spectrum sensing. This is also called the free-riding attack in distributed cognitive radio system, which will not only make the cooperative spectrum sensing unstable but also causes even more problem in the congestion communication systems. To address the free-riding attack especially in the congested cognitive radio systems, we proposed a cooperative sensing and congestion control strategy with replicator dynamics in evolutionary game theory and a priority system. By using this proposed strategy, rational secondary users have an effective incentive to participate in cooperative sensing, and the associated priority system can eliminate the free-riding attack and congestion problems in communication system, making the cognitive radio system effective and fair. Simulation results show that the average throughput achieved in the proposed cooperative sensing game is higher than the case where secondary users sense the primary user individually without cooperation. And the proposed strategy can also achieve a higher system throughput than the fully cooperative scenario.