Laser Charging-facilitated UAV Far-field Wireless Charging for WRSN

Currently, far-field wireless power transfer (WPT) and unmanned aerial vehicle (UAV) technologies provide a novel and promising approach to power wireless rechargeable sensors network (WRSN). However, in large-scale WRSNs, conventionally, the UAV performs WPT for all sensor nodes (SNs) will result in too much energy consumption in hovering, which leads to a low energy efficiency. Therefore, in order to enhance the energy efficiency, in this work, we propose to leverage UAV carried laser charging equipment to first charge the power beacons (PBs) on the ground. The PBs will then wirelessly charge the surrounding SNs by radio frequency (RF) waves. We introduce the PB-to-SN’s charging time model and schedule the SNs to receive enough energy replenishment before they deplete. The SNs’ total received energy amount maximization problem is formulated to improve the overall wireless charging efficiency. As this formulated problem is proved as non-deterministic polynomial (NP) hard problem, we further propose the UAV-power beacoN chArging (UNA) algorithm to efficiently solve the formulated problem. Extensive simulations have validated that our proposed UNA algorithm can efficiently reduce the UAV’s energy consumption and maximize the SNs’ total received energy amount.