Revisiting Practical Energy Harvesting Wireless Sensor Network with Optimal Scheduling

In this paper, we consider typical wireless energy harvesting network, where a mobile charging vehicle is scheduled to serve a wireless sensor network. Specifically, for practical considerations such as deployment restrictions, the charging vehicle could not provide full efficiency energy supply to sensor nodes. For wireless energy harvesting, there is an inevitable tradeoff between the charging distance and the angle. We focus on optimizing the charging efficiency when the distance and angle factors are concerned. Scheduling charging vehicle for rechargeable nodes in previous studies has been proved to be NP hard. Even worse, the non-linear property between the charging distance and angle should be carefully considered, which makes the problem even harder. We investigate how to minimize the recharging cycle for all the deployed sensors in network, which contains the traveling time and recharging time. With this problem, we show the charging vehicle is required to move at the shortest Hamiltonian cycle. And we present optimal charging location for each wireless charging incident. Experimental results demonstrate that, our proposed solution could enhance the charging efficiency up to 2 times comparing with the baseline scheme without optimization for angle.