Multi-UAV Collaborative Wireless Communication Networks for Single Cell Edge Users

Due to fast deployment, strong survivability and flexible scheduling, multiple unmanned aerial vehicles (UAV) can synergistically optimize the trajectory and resource allocation to improve the system performance. Aiming at the poor Quality of Service (QoS) of cell edge users (EUs) in the single cell scenario, this article designs a multi-UAV system to provide wireless communication service for EUs. Specifically, in each time slot, a communication scheduling is formed according to the channel conditions between UAVs and EUs, and the scheduled EU receives information from the associated UAV. A joint optimization scheme of UAV-user scheduling, multi-UAV transmit power and multi-UAV trajectory is proposed, with the aim to maximize the achievable sum rate of all EUs subject to the minimum average achievable rate of all ground users. In order to deal with the mixed integer non-convex problem, we decompose it into three sub-problems, and derive the approximate optimal solution of the original problem by solving the sub-problems alternatively. Simulation results demonstrate that the proposed scheme is superior to the benchmark ones and the QoS metrics of EUs are significantly increased.