Wireless Rechargeable Sensor Networks, in whichmobile chargers(MCs) are employed to recharge the sensor nodes, have attracted wide attention in recent years. Under proper charging schedules, theMCs could keep all the sensor nodes working perpetually. SinceMCs can be very expensive, this paper tackles the problem of deciding the minimum number ofMCs and their charging schedules to keep every sensor node working continuously. This problem is NP-hard; we divide it into two subproblems and propose a GCHA (Greedily Construct,Heuristically Assign) scheme to solve them. First, the GCHA greedily addresses aTour Construction Problemto construct a set of tours to 1-cover the WRSN. Energy of the sensor nodes in each of these tours can be timely replenished by oneMCaccording to the decision condition derived from aGreedy Charging Scheme(GCS). Second, the GCHA heuristically solves aTour Assignment Problemto assign these tours to minimum number ofMCs. Then each of theMCs can apply the GCS to charge along its assigned tours. Simulation results show that, on average, the number ofMCs obtained by the GCHA scheme is less than 1.1 over a derived lower bound and less than 0.5 over related work.
展开▼
