As an emerging technology, unmanned aerial vehicles (UAVs) are being developed for various applications, including UAVassisted smart city architectures, agriculture, and industrial development [1]. In particular, UAV-integrated communications have attracted significant research attention [1,2] (and the references therein), particularly for urgent or dangerous communication scenarios (eg, border detection and remote sensing). Such applications are facilitated by the low cost, deployment flexibility, and full controllability in 3D airspaces of UAVs. Compared to terrestrial systems, UAV wireless systems offer several advantages, including superior link quality for communication channels [3] and greater link connection