Completion Time and Energy Consumption Minimization for UAV-Enabled Multicasting

This letter investigates the completion time and energy consumption minimization for unmanned aerial vehicles (UAVs)-enabled multicasting over a large area. We propose a fly-and-communicate protocol, where the UAV sweeps the area by a zigzag pattern and disseminates some common information to all the ground users, whose locations are unknown at the UAV. We jointly design the flying speed, UAV altitude, and antenna beamwidth to minimize the completion time and energy consumption. For a given beamwidth, the completion time decreases monotonically with altitude. Furthermore, the optimal beamwidth can be obtained via a 1-D search with a given allowable maximum altitude. In addition, the optimal altitude and beamwidth can be obtained by alternate iteration to minimize the energy consumption.