DWDP: A Double Warning Thresholds with Double Preemptive Scheduling Scheme for Wireless Rechargeable Sensor Networks

Wireless power transfer technique provides new alternatives for solving the limited power capacity problem for so many popular mobile wireless devices, and makes wireless rechargeable sensor networks (WRSNs) promising. However, mainly due to the underestimate of the unbalanced influences of spatial and temporal constraints posed by charging requests, traditional scheduling strategies for on-demand WRSNs architecture achieve rather low charging request throughput or successful rate, posing as a major bottleneck for further improvement. In this paper, we propose a Double Warning Thresholds with Double Preemption (DWDP) charging scheme, in which double warning thresholds are used when residual energy levels of sensor nodes fall below certain thresholds. By introducing specific comparison rules, warning thresholds can be used to adjust charging priorities of different sensors, warn the upcoming recharge deadlines, as well as support preemptive scheduling. We perform extensive simulations to manifest the advantages of DWDP. Simulation results reveal that DWDP can achieve better scheduling performance, in guaranteeing the scheduling success of the high-priority task and improving stability of the system.