Game Theoretic Approaches for Spectrum Sharing in Cognitive Radio Networks: A Survey

Cognitive Radio is gaining popularity and acceptance all over the world as an efficient way to utilise the limited wireless spectrum resources. Out of the many design requirements of Cognitive Radio such as spectrum sensing, spectrum allocation, power control etc., spectrum sharing is one of main challenges to ensure peaceful co-existence of the primary and secondary users. Since multiple users compete to get maximum spectrum resources for themselves, Game Theory is an efficient framework to design robust, stable and scalable spectrum sharing schemes. In this paper, we discuss how the concepts of game theory can be exploited to design spectrum sharing protocols. Game theoretic models such as Cournot model, Bertrand model, Auction based approach for spectrum sharing, which design the spectrum sharing scenario from different aspects are also presented. Further, the paper throws light on the following scenario in which users competing for spectrum resources may have no incentive to co-operate and may also exchange false information about the channel conditions to gain more access to spectrum. Cheat-proof strategies are thus developed to maintain the efficiency of spectrum usage. Finally, this paper puts forth a comparative study between the various models along with research challenges and future directions in game theoretic modelling.