Rescheduling of Nodes Duty Cycles to Prevent Partitioning in Wireless Sensor Networks
Abstract
For the perfect operation of a WSN both requirements of sensing coverage and network connectivity are needed simultaneously. The method used in this work satisfies both of those requirements. For the sensing coverage, it uses randomized scheduling algorithm, in which each sensor node randomly selects one of the k predefined working subset. At any time only sensor nodes in one subset are active and nodes in the other subsets are in the sleep mode. Then, the algorithm turns on extra sensor nodes if necessary for the network connectivity. The problem of this method is some of extra-on nodes should be active more than one additional subset and even should be stay on all the time. Also extra-on nodes that are turned on to participate in other nodes routing, sometimes are subjected to many transmissions and receptions. So, they are faced with rapid battery depletion and this problem may lead to network partitioning. In this paper, we utilize rescheduling methods to minimize the number of extra on sensor nodes. By probing mechanism algorithms that allow for some nodes to change their working schedule, number of extra on nodes is reduced up to 35%.