Trajectory Design for UAV Assisted Wireless Networks

Unmanned aerial vehicles (UAVs) can enhance the performance of cellular networks, due to their high mobility and efficient deployment. In this paper, we consider a single-UAV assisted wireless communication system, where the UAV is deployed as an aerial base station (BS) to serve ground users. We maximize the transmission rate of ground users in the downlink communication by optimizing the UAV trajectory. To account for the impact of the ground BS on the UAV trajectory design, we provide a higher reward for the UAV to serve at a cell edge position. The cost function takes into account both the energy consumption during moving and hovering. We formulate our problem as a route selection problem in an acyclic directed graph, where each vertex and each edge are associated with a reward and a cost, respectively. The shortest path (SP) scheme is used to determine the optimal trajectory. Simulation results show that the SP scheme achieves the highest payoff among the compared schemes. Finally, we provide an application scenario based on our campus map to illustrate how the UAV determines the optimal trajectory under the SP scheme.