A novel multi-relay selection and power allocation scheme for cooperation in cognitive radio ad hoc networks based on principle-agent game

With the capability of reducing multi-path fading and raising channel capacity by obtaining spatial diversity gain, cooperative communication is effective in functionality improvement of wireless networks. In this paper, based on the characteristic of distribution and time-variance in cognitive radio ad hoc networks (CRAHNs), a dynamic game framework is proposed for studying the interactions between source node and relays, and choosing adaptive relays to join the cooperation. The constraint optimization problem is further formulated for each user to maximize throughput while avoiding interruption to primary users. We model the scene as principle-agent game and prove the existence of subgame perfect Nash equilibrium by backwards induction. Moreover, we develop a distributed algorithm to make the secondary users improve their throughput and power allocation among them. The simulation results show that the proposed scheme can significantly increase the power efficiency and decrease the average power consumption.