Backhaul-Aware Trajectory Optimization of Fixed-Wing UAV-Mounted Base Station for Continuous Available Wireless Service

Due to high mobility and flexibility, unmanned aerial vehicles (UAVs) have attracted significant attention from both academia and industry in wireless communications. Different types of UAVs are used for different wireless applications. However, there is a dilemma that no suitable approach is available to provide continuous available long-time wireless coverage from UAV-mounted base stations (UBSs) since rotary-wing UAVs require frequent energy replenishment while fixed-wing UAVs cannot hover at fixed locations. In this paper, the fixed-wing UBS is considered for providing continuous available wireless services to ground users with a novel dynamic resource allocation framework. In particular, the optimal resource allocations for both out-band and in-band wireless backhaul schemes are derived using convex optimization theory. Moreover, the sequential convex optimization method is used to obtain the energy-efficient trajectories. Finally, extensive simulation results are provided to verify the effectiveness of our proposed method. A comparison of out-band and in-band backhaul schemes is also provided.