Cooperative Spectrum Allocation for Cognitive Radio Network: An Evolutionary Approach

Cooperative sharing of spectrum among one primary user (PU) and multiple secondary users (SUs) helps to enhance the throughput of the whole system. In this paper, we propose a two-tier game in the sharing of spectrum in which SUs make their decisions on whether to cooperate under replicator dynamics and the PU adjusts its strategy to allocate time slots for the cooperative SUs´ transmission. Furthermore, we develop the distributed algorithm to describe the learning process of SUs, and prove that the dynamics can converge to the evolutionary stable strategy (ESS) efficiently, which is actually the optimal strategies of both PU and SUs. Simulation results show that our proposed mechanism converges to ESS automatically, at which point all the SUs will remain their strategies. In addition, it is shown that this mechanism helps the SU to share information and gain higher transmission rate than fully cooperative or non-cooperatively scenario.