Zoning based block service policy in a MAC protocol with RF recharging

Among the main problems in radio frequency based recharging, which is being increasingly used to extend maintenance-free operation of wireless sensor networks, is the dependence of the recharge level on the distance of the node in question from the node that emits the recharging pulse. To address this, we propose a zoning scheme in which the polling patterns and service policy differ from zone to zone in order to reduce the energy consumption of more distant nodes so as to match their lower recharge increment. We analyse the performance of the proposed scheme through probabilistic analysis and renewal theory, and show that it leads to equalisation of node lifetimes and extends the time interval between recharge pulses. We also discuss the possibility of addition of helper recharging nodes.