This paper studies a new unmanned aerial vehicle (UAV)-enabled wireless power transfer (WPT) system, where a UAV-mounted energy transmitter (ET) broadcasts wireless energy to charge distributed energy receivers (ERs) on the ground. In particular, we consider a basic two-user scenario, and investigate how the UAV can optimally exploit its mobility via trajectory design to maximize the amount of energy transferred to the two ERs during a finite charging period. We characterize the achievable energy region of the two ERs, by optimizing the UAV's trajectory subject to a maximum speed constraint. We show that when the distance between the two ERs is smaller than a certain threshold, the Pareto boundary of the energy region is achieved when the UAV hovers above a fixed location between them during the whole charging period; while when their distance is larger than the threshold, to achieve the boundary of the energy region, the UAV in general needs to hover and fly between two different locations above the line connecting them. Numerical results show that the optimized UAV trajectory can significantly improve the WPT efficiency and fairness of the two ERs, especially when the UAV's maximum speed is large and/or the charging duration is long. Index Terms-Wireless power transfer, unmanned aerial vehicle (UAV), energy region, trajectory design. 978-1-5386-3920-7/17/$31.00 ©2017 IEEE
Xu et al. in REF investigate a UAV transferring energy to the terrestrial devices.
UAV-Enabled Wireless Power Transfer: Trajectory Design and Energy Region Characterization
2017 IEEE Globecom Workshops (GC Wkshps)
2017 IEEE Globecom Workshops (GC Wkshps)
Computer Science Mathematics