Multiple Relay Selection Based on Game Theory in Cooperative Cognitive Radio Networks

Due to the inefficiency of traditional fixed spectrum allocation policies, the paradox of apparent spectrum scarcity occurs while most of the bands are underutilized. This has prompted proposals for Dynamic spectrum sharing (DSS), which explains why Cognitive radio network (CRN) has been widely accepted as a promising approach to settle inefficient usage of scarce available radio spectrum. As a subset of DSS, Dynamic spectrum leasing (DSL) strategy has been proposed based on game idea, where Primary user (PU) has an incentive to allow Cognitive users (CUs) to access its licensed spectrum for a fraction of time in exchange for revenue. This paper proposes an approach, named multiple relay selection based on Game theory (GTMRS), to optimize the utilities of PU and CUs as a whole, where a pricing-based spectrum leasing mechanism is applied. While the parameter price c is jointly determined by PU and CUs, all selected cognitive user's optimal cooperative powers can be satisfied through a non-cooperative game among themselves. Numerical results show that more CUs are involved in the cooperation and both utilities of PU and CUs as a whole are improved, which means the whole system throughput is increased.