UAV Beam Alignment for Highly Mobile Millimeter Wave Communications

Unmanned Aerial Vehicles (UAVs) have the advantages of high mobility and flexibility that can be potentially used as aerial base stations (BSs) to provide millimeter-wave (mmWave) communication with ground users. However, the UAV mmWave beamforming must be carefully designed to provide directional transmission and support reliable connections. In this paper, we consider a UAV mmWave system, where the UAV serves as a BS to cover mobile users on the ground. Firstly, we study the beam training and propose beam training codebook designs for both insufficient and sufficient beam training cases. Then, we propose efficient beam tracking methods to predict the beam direction with user mobility, where both random and inertial motion are considered. Simulation results show that the average downlink capacity increases with the proposed beam training codebook. Further, the mean angular error of our proposed beam tracking is lower than existing method.