Towards Cheat-Proof Cooperative Relayfor Cognitive Radio Networks

In cognitive radio networks, cooperative relay is a new technology that can significantly improve spectrum efficiency. While the existing protocols for cooperative relay are very interesting and useful, there is a crucial problem that has not been investigated: Selfish users may cheat in cooperative relay, in order to benefit themselves. Here by cheating we mean the behavior of reporting misleading channel and payment information to the primary user and other secondary users. Such cheating behavior may harm other users and thus lead to poor system throughput. Given the threat of selfish users´ cheating, our objective in this paper is to suppress the cheating behavior of selfish users in cooperative relay. Hence, we design the first cheat-proof scheme for cooperative relay in cognitive radio networks, and rigorously prove that under our scheme, selfish users have no incentive to cheat. Our design and analysis start in the model of strategic game for interactions among secondary users; then they are extended to the entire cooperative relay process, which is modeled as an extensive game. To make our schemes more practical, we also consider two aspects: fairness and system security. Results of extensive simulations demonstrate that our scheme suppresses cheating behavior and thus improves the system throughput in face of selfish users.