NOMA Throughput and Energy Efficiency in Energy Harvesting Enabled Networks

An energy harvesting (EH) enabled network is capable of delivering energy to users, who are located sufficiently close to the base stations. However, the wireless energy delivery requires much more transmit power than what the normal information delivery does. It is very challenging to provide the quality of the wireless information and power delivery simultaneously. It is of practical interest to employ nonorthogonal multiple access (NOMA) to improve the network throughput, while fulfilling the EH requirements. To realize both EH and information decoding, this paper considers a transmit time-switching (transmit-TS) protocol. Two important problems of users’ max-min throughput optimization and energy efficiency maximization under power constraint and EH thresholds, which are non-convex in beamforming vectors, are addressed by efficient path-following algorithms. In addition, the conventional power splitting (PS)-based EH receiver is also considered. The provided numerical results confirm that the proposed transmit-TS based algorithms clearly outperform the PS-based algorithms in terms of both, throughput and energy efficiency.