The Research Of Node Sleep-scheduling Method In Wireless Sensor Network

Wireless sensor networks (WSNs) is a wireless network consisting of a large numberof stationary or mobile sensors in manner of self-organization and multi-hop. Since theWSNs have many advantages such as easy-to-deployment, layout-intensive, low-cost andmaintenance-free, it is used widely in national defense, environmental monitoring, trafficmanagement, health care, anti-terrorism and other areas.In practice, a large number of sensor nodes were deployed in target area to ensure thequality of service of the wireless sensor networks. However, this way of deployment willcause redundancy, channel conflict between nodes, seriously affect the life cycle ofwireless sensor network. Therefore, how to extend the network lifetime without affectingthe quality of network connectivity and coverage is a very important question of wirelesssensor networks. The node sleep scheduling method is most commonly and directly, whichuse of the redundant network deployment and keeping the redundant nodes off. It can besaving the energy consumption of nodes and prolonging the network life cycle. Based onthe existing node sleep-scheduling method, this paper has carried out the followingstudies:Firstly, a node sleep-scheduling method based on grid partition is proposed. For agiven target area and communication radius of the network, the method use the gridpartition policy to divide the network. On this basis, the node sleep-scheduling methodbased on grid partition is implemented to extend the network life cycle.Secondly, a tolerable coverage based node sleep-scheduling method in hybridwireless sensor networks is proposed. The method determines the various types ofredundant nodes table by the node’s perception of the radius and the communication radius.Then the redundancy of each type of node is calculated based on the redundancy table andthe number of neighbor nodes. The redundant node judgment rule is measured bycomparing the redundancy of each type of node with the coverage goal. The redundantnodes which will be turned off are determined by the judgment rule to achieve the purposeof prolonging the network life cycle at last. Finally, through a large number of simulation experiments under the differentparameters, the results show that the two node sleep-scheduling method can effectivelyreduce the energy consumption of the network and extend life cycle of the network.