QoS-Based Robust Power Optimization for SWIPT NOMA System With Statistical CSI

Simultaneous wireless information and power transfer (SWIPT) that can prolong the lifetime of energy-limited wireless users has drawn considerable attention. In this paper, the power consumption optimization problem is investigated in SWIPT non-orthogonal multiple access (NOMA) system based on statistical channel state information (SCSI) to meet the probabilistic constraints of users' quality of service (QoS) and energy harvesting. We assume that the strong user can decode information and harvest energy at the same time by employing power splitting, the harvested energy is used to communicate with other users, and the number of communication in a slot follows Poisson distribution. We derive the closed-form expressions of optimal power consumption with given users' QoS by classification discussion. Simulation results are investigated to demonstrate the validity of closed-form expressions and that the SWIPT NOMA can outperform the SWIPT OMA in terms of the outage performance.