Two-Way Reflecting Communication with UAV-Borne Reconfigurable Intelligent Surfaces

This paper investigates the unmanned aerial vehicle (UAV)-aided two-way reflecting (TWR) communication system under the probabilistic line-of-sight (LoS) channel, where a UAV equipped with an RIS is deployed to assist two ground nodes in their information exchange. An optimization problem with the objective of maximizing the minimum average (expected) achievable rate is formulated to design the communication scheduling, the RIS's phase, and the UAV trajectory. To solve such a non-convex problem, we propose an efficient iterative algorithm to obtain its suboptimal solution. Simulation results show that our proposed design provides new insights into the elevation angle-distance trade-off for the UAV-aided TWR communication system, and improves the rate by 28% compared to the scheme under the conventional LoS channel.