Mobile Charger Scheduling using Partial Charging Strategy for Rechargeable WSNs

In wireless rechargeable sensor networks (WRSNs), one of the major limitations is that the batteries of the sensor nodes have small capacity, owing to the small size of sensor nodes. WRSNs may create a performance bottleneck for the long lasting monitoring tasks due to limited capacity batteries. Recent advancements of Wireless energy transmitters(WETs) are useful to recharge the sensor nodes wirelessly. This is mostly accomplished by using mobile chargers(MCs) with WETs. In this work, we focus on the scenario where energy consumption of nodes are heterogeneous, and our goal is to maximize the network lifetime by efficiently scheduling a mobile charger. As an improvement to the works done till now, the proposed algorithm implements partial charging of nodes with a possible preemption after each time quantum(which is a judiciously evaluated using some heuristics). Our evaluation results show that our algorithm out-performs the nearest-job-next with preemption (NJNP) strategy and the Recha algorithm wrt to two important criteria - namely network lifetime, and number of nodes alive in a certain amount of time. Also we analyse the set of parameters for which the proposed algorithm gives best results.