Particle swarm optimization for charger deployment in wireless rechargeable sensor networks

In Wireless Rechargeable Sensor Networks (WRSNs), wireless chargers can recharge batteries of sensor nodes so that they can operate sustainably. Since wireless chargers are costly and have limited charging distances and angles, how to apply as few as possible chargers to cover all sensor nodes and satisfy their energy requirements is thus an important and challenging problem. This paper introduces the PSCD (Particle Swarm Charger Deployment) algorithm and the IPSCD (Improved PSCD) algorithm using the Particle Swarm Optimization (PSO) concept to nearly optimize WRSN charger deployment. PSCD and IPSCD estimate charging efficiency according to the distance and angle between chargers and sensor nodes. They then, on the basis of PSO, utilize the local optimum and the global optimum to adjust locations and antenna orientations of chargers to make WRSNs sustainable. We perform experiments using practical wireless chargers to obtain charging efficiency data. Based on the data, PSCD and IPSCD are simulated for obtaining the best parameter setting, and compared with two related greedy algorithms to show their superiority.