Wireless Powered UAV-Enabled Communications over Mixed LoS and NLoS Channels

This paper considers an unmanned aerial vehicle (UAV)-assisted communication system with simultaneous wireless information and power transfer (SWIPT). In modeling the composite channel, the probability of line-of-sight (LoS)/non-LoS is taken into account, along with log-normal shadowing. Moreover, for small-scale fading, Nakagami-m and Rayleigh distributions are considered for the LoS and non-LoS (NLoS) conditions, respectively. For enabling radio-frequency (RF) energy harvesting, a hybrid power-splitting (PS) and time switching (TS) based architecture is considered at the UAV. In order to provide relay cooperation to the remote mobile user, the UAV performs decode-and-forward (DF) operation. To examine the system performance, we first derive the outage probability (OP) expression utilizing the Gauss–Hermite quadrature for different shadowing and fading channel combinations. In addition, the system throughput and energy efficiency expressions are obtained for both shadowed and un-shadowed channels and verified through Monte Carlo simulations.