Radio Resource Management for Optimizing Energy Efficiency of D2D Communications in Cellular Networks

This paper deals with the energy-efficient resource allocation for device-to-device (D2D) communication underlaid cellular networks. Specifically, our design objective is to maximize the weighted energy-efficiency (EE) of D2D links while guaranteeing the minimum data rate for each cellular link. To solve this problem, we first characterize the optimal power allocation solution for the cellular links so that the original resource allocation problem can be transformed into the joint subchannel and power allocation problem for D2D links. We then propose a relaxation-based algorithm to solve the transformed problem. We prove that the proposed algorithm converges to the optimal solution of the original problem if no D2D link utilizes the maximum transmit power. Extensive numerical results demonstrate that the proposed algorithm achieves the optimal performance and it outperforms existing algorithms.