Joint Uplink and Downlink Resource Allocation for NOMA-enabled D2D Communications

This letter investigates the joint uplink and downlink resource allocation problem, where the non-orthogonal multiple access (NOMA) technology is applied to enhance device-to-device (D2D) communications. In order to maximize the sum data rate of NOMA-enabled D2D groups while guaranteeing the minimum data rate requirements of both cellular users (CUs) and D2D groups, we first design a subcarrier assignment algorithm to assign the downlink and uplink subcarriers for D2D groups, and then transform the problem into a convex optimization to obtain the optimal power allocation. Simulation results demonstrate the remarkable improvement in terms of data rate of D2D groups by using our algorithms.