Energy efficient incentive resource allocation in D2D cooperative communications

Device-to-device (D2D) cooperation can improve both the system performance and Quality of Services (QoS) of users with bad channel qualities. However, cooperation consumes valuable power of a terminal to help others and thus is not preferred by the terminal. So it is important to design schemes to stimulate selfish terminals to cooperate. Defining energy efficiency as incentive parameters, this paper proposes a novel resource allocation scheme to encourage users to relay data for others with the reward of transmitting resource including time and power. Since the optimal algorithm is highly complicated, the proposed energy efficient incentive resource allocation scheme is a suboptimal solution which is composed of three steps. Firstly, D2D relay users are selected for others in bad channel condition. Secondly, the two-user case resource allocation problem is formulated to simplify the original problem in cellular networks. Finally, a two-dimensional search method is designed to solve the two-user case problem based on monotonicity analysis. Simulation results demonstrate that the proposed scheme can stimulate users to implement D2D relay to achieve better performance in energy efficiency and throughput. It is also shown that the performance of the proposed scheme is close to that of the optimal one.