Air-Ground Physical Layer Security Transmission Scheme Assisted by Reconfigurable Intelligent Surfaces

Unmanned aerial vehicles (UAVs) play a crucial role in wireless communication networks due to their mobility, line-of-sight (LoS) link, flexible, and on-demand deployment advantages. To address the challenge of secure air-to-ground transmission, this paper investigates a communication model where UAV is equipped with reconfigurable intelligent surfaces (RIS) to serve as relay. Specifically, the beamforming (BF), RIS phase shift and UAV flight trajectory are jointly optimized to maximize the average secrecy rate (ASR). Then, the non-convex problem is decomposed into three sub-problems and addressed using alternating optimization (AO) algorithm. The results of the simulations serve to confirm the efficacy of the proposal regarding the PLS scheme.