On-demand Mobile Charger Scheduling for Effective Coverage in Wireless Rechargeable Sensor Networks

Using mobile chargers in wireless rechargeable sensor networks is an option for charging the nodes due to the high cost of power chargers. In order to achieve some performance requirement such as coverage, it is necessary to effectively schedule the mobile chargers to serve every node in the network. We notice that nearly all previous works on mobile charger scheduling assume that the mobile chargers move along predetermined paths which are computed based on perfect priori information. In this paper, we consider the problem of scheduling mobile chargers in an on-demand way to maximize the covering utility. On receiving re-charging requests from the nodes, the mobile charger decides how to move. The covering utility is defined to quantify the effectiveness of event monitoring. We propose three heuristics for this problem after proving its NP-Completeness. We further generalize our solutions to accommodate the multiple mobile chargers case. Finally we evaluate our solutions through extensive trace-driven simulations.