Joint Optimization of STAR-RIS Assisted UAV Communication Systems

TL;DR

This paper proposes a joint optimization framework for STAR-RIS assisted UAV communication systems, enhancing sum rate performance by optimizing beamforming, UAV trajectory, and power allocation.

Contribution

It introduces a novel joint optimization approach for STAR-RIS and UAV parameters, demonstrating significant performance improvements over traditional RIS.

Findings

STAR-RIS outperforms traditional RIS in sum rate

UAV trajectory is optimized closer to STAR-RIS for better performance

Energy splitting depends on UAV's real-time trajectory

Abstract

In this letter, we study the simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) assisted unmanned aerial vehicle (UAV) communications. Our goal is to maximize the sum rate of all users by jointly optimizing the STAR-RIS's beamforming vectors, the UAV's trajectory and power allocation. We decompose the formulated non-convex problem into three subproblems and solve them alternately to obtain the solution. Simulations show that: 1) the STAR-RIS achieves a higher sum rate than traditional RIS; 2) to exploit the benefits of STAR-RIS, the UAV's trajectory is closer to STAR-RIS than that of RIS; 3) the energy splitting for reflection and transmission highly depends on the real-time trajectory of UAV.