Network Sum-Rate Maximization for SWIPT-Enabled Energy-Harvesting Downlink/Uplink NOMA Networks

This paper considers the problem of network sum-rate maximization in energy-harvesting non-orthogonal multiple-access (NOMA) networks with simultaneous wireless information and power transfer (SWIPT). Particularly, the aim is to maximize the network sum-rate in the downlink (DL) and uplink (UL) directions via joint time-switching and power allocation (J-TS-PA), while ensuring users' quality-of-service (QoS). However, problem J-TS-PA happens to be non-convex, and thus is computationally-intensive. Alternatively, a near-optimal low-complexity iterative solution procedure is devised to solve problem J-TS-PA. Simulation results are presented to evaluate the proposed solution procedure, which is shown to yield comparable network sum-rate to the J-TS-PA scheme, and superior to its OMA-based counterpart, while satisfying QoS constraints.