Optimal Design on UAV-Enabled Downlink Wireless Information and Energy Transfer

Abstract

This paper investigates wireless information transfer (WIT) and wireless energy transfer (WET) in an unmanned aerial vehicle (UAV) enabled downlink wireless communication system, where both the UAV and the ground terminal (GT) are battery-empowered. When the UAV transmits energy to the GT, the GT harvests energy and stores in its battery, and when the UAV transmits information to the GT, the GT uses the stored energy from the battery to receive and decode the information. We formulate the UAV’s optimal WIT and WET design as a constrained Markov decision process (MDP) problem over a finite time horizon. Due to the high complexity to solve this problem, we then propose a suboptimal policy by studying the optimal policy structure. Numerical results show that the proposed suboptimal policy can achieve close-to-optimal performance. We also show the impact of the UAV’s altitude on the throughput performance.