Non-orthogonal Multiple Access in SWIPT Enabled Cooperative D2D Network

In this paper, we investigate resource allocation in a downlink cooperative communication system. In the scenario where cellular users (CUs) and the base station (BS) cannot communicate directly, D2D user pairs participate in the cooperative communication to complete forwarding information required by CU and themselves through non-orthogonal multiple access (NOMA). The application of simultaneous wireless information and power transfer (SWIPT) ensures that D2D users save their own energy during the forwarding process. The ultimate optimization goal is to maximize the achievable rate of D2D user pairs under the condition of guaranteeing CU's quality of service (QoS). A stepwise iterative algorithm is proposed to obtain the suboptimal solution to the problem. By comparing with the ergodic optimal solution, numerical simulations show that the proposed algorithm can approximate the optimal solution with low computational cost in a certain error range.