Common Throughput Maximization in Wireless Powered Communication Networks With Non-Orthogonal Multiple Access

This paper considers the wireless powered communication networks (WPCNs) where one hybrid sink (H-sink) coordinates the wireless energy/information transmissions to/from a set of one-hop nodes powered by the harvested radio-frequency energy only, and aims to maximize the common throughput (CT) of nodes. Specifically, we investigate the WPCN using non-orthogonal multiple access, where all nodes transmit information simultaneously to H-sink and H-sink performs successive interference cancellation to alleviate the noise from other nodes. Energy transfer duration, data transmit powers of nodes and the decoding order of nodes' signals are jointly optimized to maximize the CT. We first formulate the CT maximization (CTM) as a non-convex optimization problem, then separate the CTM problem into a number of subproblems to solve, and finally recover the optimal solution of the original problem from the optimal solutions of subproblems. Our CTM scheme significantly outperforms the available scheme using up all harvested energy. Furthermore, we propose an efficient algorithm to maximize the sum throughput while guaranteeing that the maximum CT is achieved. This scheme further greatly increases the sum throughput.