RIS Relaying UAV-Aided WPCN for Throughput Maximization

Abstract

This paper studies a reconfigurable intelligent surface (RIS) relaying unmanned aerial vehicle (UAV)-aided wireless powered communication network (WPCN), where a RIS acts as a relay and a UAV acts as a hybrid access point (HAP). Under this setup, we jointly optimize the UAV’s 2D hovering location and reflective beamforming vector at the RIS, for the purpose of maximizing the minimum throughput among all the ground users. To solve the non-convex min-throughput maximization problem, we propose a low-complexity alternating optimization approach to divide the original problem into two subproblems and solve them sequentially. In particular, we optimize the UAV’s 2D hovering location based on successive convex approximation (SCA) and the reflective beamforming vector by applying the technique of semi-definite relaxation (SDR). Numerical results verify the efficiency and performance of the algorithm and show that the proposed RIS relaying UAV-aided WPCN achieves significant performance gains over the conventional WPCN.