Joint Attitude and Power Optimization for UAV-Aided Downlink Communications

In this paper, we investigate the unmanned aerial vehicle (UAV)-aided communications, where a UAV as an aerial base station (BS) transmits data to multiple ground terminals (GTs) simultaneously and an antenna array is equipped on the UAV. Note that in practice, the spatial resolution of antenna array varies with different directions. Thus, given one user distribution, the direction of antenna array on UAV may be optimized to support the best multiuser spatial separation. Based on this observation, we propose to maximize the minimum throughput of all GTs by jointly optimizing the attitude of UAV and the transmit power for each GT, where the attitude includes both location and direction information. We develop two efficient sub-optimal solutions for this non-convex problem. The interference among the co-scheduled GTs is dramatically reduced through direction adjustment of antenna array. Finally, simulation results are provided to verify the proposed algorithms.