UAV-Assisted Wireless Powered Relay Networks With Cyclical NOMA-TDMA

Abstract

We optimize the performance of an unmanned aerial vehicle (UAV)-assisted wireless powered relay network (WPRN), where the UAV is used as a radio-frequency (RF) power transmitter and as a communication relay between energy harvesting users (EHUs) and a base station (BS). The EHUs are assigned to radial service sectors, centered around the base station (BS), and employ a combination of non-orthogonal multiple access (NOMA) and time-division multiple access (TDMA), referred to as cyclical NOMA-TDMA, for multiple access. For performance optimization, maximization of the sum rate in all service sectors and maximization of the minimal sum rate per service sector are considered, and the optimal radii of the UAV's circular trajectory and the optimal allocation of the UAV's transmit power across the service sectors are determined.