Joint User Grouping, UAV Deployment and Multicast Precoder Optimization in UAV-enabled Networks

Unmanned aerial vehicles (UAVs) with multiple antennas have the potential to significantly enhance content delivery performance of cache-enabled UAV networks. In this work, we jointly investigate user grouping, UAV deployment and multicast precoder optimization problem in multi-UAV-enabled networks, where UAVs are allowed to store user-requested contents. We formulate the joint optimization problem as a throughput maximization problem. As the formulated problem is a mixed-integer non-linear programming (MINLP) problem, we transform it into two subproblems which are solved iteratively. Specifically, we first propose a mean-shift-based user grouping algorithm and design a UAV deployment strategy based on first-order Taylor expansion. We then propose a successive convex approximation-based iterative algorithm and obtain a multicast precoder strategy for individual user groups. Simulation results demonstrate the effectiveness of the proposed algorithms.