Joint Optimization of Altitude and Beamwidth for UAV-Powered Wireless Sensor Networks

In this paper, we consider an unmanned aerial vehicle (UAV)-powered wireless sensor network (WSN) in which a UAV transfers wireless energy to ground sensor (GS) nodes using a directional antenna, and the GS nodes use the harvested energy to transmit sensing information back to the UAV. Considering the tradeoff aspect in adjusting the antenna beamwidth and altitude of the UAV, we jointly optimize the altitude and beamwidth to collect sensing data from all GSs as quickly as possible. The numerical analysis verifies the existence of unique altitude and beamwidth values that minimize the data collection time. The simulation result indicates that the use of a directional antenna and the joint optimization of altitude and beamwidth are essential for maximizing the performance of UAV-powered WSN systems.