Spectrum sharing based on iterated Prisoner’s Dilemma in cognitive radio

We study a spectrum sharing problem where multiple systems coexist and interfere with each other. An analysis is proposed for the distributed spectrum sharing based on the Prisoners´ Dilemma in cognitive radios (CRs). Selfish and rational CRs greedily spread spectrum space in order to maximize their own rates, which leads to Nash equilibrium; but with long term interaction i.e. Iterated Prisoner´s Dilemma, CRs can come to cooperate and acquire the social optimal point by using different evolutionary strategies such as Tit for Tat, Pavlov etc. In simulation we compare with the performance of the different evolutionary strategies in noise-free and noise environments and find that Tit for Tat strategy can get the best performance.