Resource Allocation for Energy Harvesting D2D Communications Underlaying NOMA Cellular Networks

This paper studies a resource allocation problem utilizing the power splitting (PS) architecture in SWIPT (Simultaneous Wireless Information and Power Transfer)- enabled device-to-device (D2D) communications underlaying a non-orthogonal multiple access (NOMA) cellular network, where the cellular users receive signal from the base station at different power levels. The device transmitter and receiver employ a PS architecture; hence a fraction of the received signal power is used for energy harvesting and the rest is used for information decoding. The device transmitter communicates with the device receiver such that the minimum rate requirement of the cellular users in the network is guaranteed. The formulated resource allocation problem, which aims at maximizing the throughput of D2D communications, is non- convex. Analysis and simplifications lead to an optimal solution obtained using the gradient descent method. The numerical results depict that the NOMA cellular network offers considerable D2D throughput gain over the benchmark orthogonal multiple access network. The results are significant for the adoption of energy harvesting D2D communications combined with NOMA-based cellular networks in the future.