Multi-UAV Two-Way Relaying: Joint Scheduling, Transmission Power, and Trajectory Optimization

In this correspondence, we present a proposal for a system that utilizes multiple unmanned aerial vehicles (UAVs) for two-way relaying. This system aims to enhance the information exchange among various pairs of ground users (GUs) while considering the interference between the UAVs and ground GUs. Our approach involves optimizing transmission scheduling parameters, transmission powers, and UAVs' trajectories jointly. Specifically, we aim to maximize the minimum average throughput rate of GUs, an important metric for evaluating the system's performance. To address the non-convex problem, we use a combination of the Branch-and-Bound framework and the Successive Convex Approximation technique to solve the joint optimization problem. We then propose an iterative algorithm that employs the block coordinate descent method for the optimization problem. Experimental results demonstrate that the proposed multi-UAV two-way relaying system outperforms other benchmark systems in system throughput for different distributions of GUs.