On-demand vehicle-assisted charging in wireless rechargeable sensor networks

Abstract

Wireless power transfer technology opens up possibilities for charging the batteries of sensors wirelessly by wireless charging vehicles (WCVs), which increases the lifetime of Wireless Rechargeable Sensor Networks (WRSNs). Most of the existing studies do not consider the energy depletion of WCVs’ batteries during their travel through the network area, which may cause WCVs stranded in between their charging tours. In this paper, we have proposed a vehicle-assisted framework for charging sensors in WRSN, and formulated a bi-objective charge scheduling problem, where WCVs start their travel from a base station, charge the sensors, and finally return back to the base station with an aim to maximize the number of alive sensors while minimizing the total energy consumed for WCVs’ movement. The problem is proved to be NP-complete. Offline and online algorithms are proposed to solve the problem. An upper bound on the percentage of sensors that can be charged is also derived. Detailed simulations with sufficient number of WCVs have been carried out to investigate the performance of our proposed algorithms while comparing with the existing schemes, which reveals that our proposed algorithms excel in charging a large number of sensors compared to the existing algorithms.