  This letter aims to present a novel approach for unmanned aerial vehicles
(UAV)' path planning with respect to certain quality of service requirements.
More specifically, we study the max-min fairness problem in an air-to-ground
communication system where multiple UAVs and multiple ground stations exist. We
jointly optimize the UAVs trajectories and power allocation as well as the user
scheduling. To this end, we propose an effective iterative algorithm that
relies on the successive convex approximation and the block coordinate decent
techniques.
