Joint Power and Trajectory Design for UAV-Relayed Wireless Systems

In this letter, an unmanned aerial vehicle (UAV) is employed as relay to build temporary communication links for disconnected ground nodes. To improve the fairness and energy efficiency, two scenarios are investigated. First, for given transmission power budget, we consider maximizing the minimum information rate by joint power and trajectory optimization over a time horizon. Then, for given required information rate, we consider minimizing the sum-power consumption. These two objectives are both non-convex, which is intractable to solve. To address these objectives, we propose iterative algorithms to approximate the solution by successive convex optimization techniques. Numerical results show the effectiveness of the proposed approaches.