Trajectory and Communication Design for UAV-Relayed Wireless Networks

In this letter, an unmanned aerial vehicle (UAV) is employed to relay data for multiple pairs of ground users in time-division manner. Our objective is to maximize the minimum average information rate of each communication pair by optimizing the time slot allocation, power allocation, and UAV trajectory. This is a non-convex optimization problem, which is challenging to address. First, we approximately solve the subproblem of time slot allocation with fixed power and trajectory, as well as the subproblem of power and trajectory optimization with fixed time slot allocation. Then we propose an efficient iterative algorithm to approximate the optimal solution by solving the two subproblems alternately. Numerical results show the effectiveness of the proposed algorithm.