A Hybrid Charging Scheme for Minimizing the Number of Energy-Exhausted Nodes in Wireless Rechargeable Sensor Networks
Tingdan Deng, Shuqi Tang, Yue Chen, Feng Lin
Abstract
In wireless rechargeable sensor networks (WRSNs), researchers address the energy problem in wireless sensor networks by introducing fixed chargers or mobile chargers to recharge energy-starving nodes. The majority of existing studies on WRSNs investigate either the deployment of fixed chargers or the scheduling of mobile chargers to charge sensor nodes. In this work, we investigate the hybrid charging problem, i.e., the problem of recharging nodes by fixed chargers and mobile chargers cooperatively, in scenarios with arbitrary node distribution, with the goal of minimizing the number of energy-exhausted nodes. We deduce the problem into two sub-problems, namely, the Fixed Chargers Deployment Problem (FCDP) and the Mobile Charger Path Planning problem (MCPP), respectively. We present the definitions of these two sub-problems and prove both of them are NP-hard. Then, we propose a hybrid charging scheme which comprises of two algorithms to address these two sub-problems one by one. Extensive simulation experiments confirm the scheme’s effectiveness and the results show that the proposed scheme outperforms the existing methods(i.e., TCA-MCPPA, FCDA-JERDC, MSC) in minimizing the number of energy-exhausted nodes. In the uniform node distribution, they are reduced by 79.62%, 88.2%, and 95.01%, respectively. In the triple Gaussian node distribution, they are reduced by 99.90%, 99.71%, and 99.98%, respectively.