Design And Research On Routing Strategy For Wireless Sensor Network Used In Water-Saving Irrigation Control System

Using the emerging Wireless Sensor Network (WSN) in water-saving irrigation control system can solve the technics problem of transferring the crop's require water information, and then to impel the development of irrigation control system. While the routing strategy for WSN is a key technology to data transmission, and it is a necessary condition for the network to work stably.The main part of this dissertation is to design a routing strategy for WSN applying to water-saving irrigation control system. Because the energy of each sensor node is extraordinarily limited, the all-important aim of designing routing strategy for WSN is to keep the balance of energy consumption among nodes, and then to save energy in effect.In order to design a routing strategy fit for farm irrigation area, a network structure of WSN is presented firstly. The structure aims the characteristic of soil humidity which changes smoothly, the entire farm irrigation area is divided into many basic irrigation areas, and the sensor nodes placed in one basic irrigation area form a cluster in network. Then a node-placement density control algorithm based on estimating energy consumption is studied. With the purpose of balancing the energy consumption, the algorithm can help placing the sensor nodes intendedly, and increase the node density in key area. After analyzing the requirements of routing protocol for common WSN, a subarea routing strategy is presented finally.In the view of network structure, the subarea routing strategy is a hierarchical routing protocol. The whole network is divided into several different clusters, and each cluster is made up of a cluster head and some member nodes. The member nodes only sense and transmit data to cluster head. While the cluster head not only senses but also receives and fuses datas from member nodes, then the cluster head sends the aggregated data to sink node. The whole routing process consists of two phases: prepare phase and transmit phase. During the prepare phase, the network is formed and the first cluster head of each cluster is selected. During the transmit phase, the datas of member nodes are transmited to cluster head and the aggregated datas of cluster head are transmited to sink node. Moreover the alteration of cluster head in each cluster is also implemented in this phase. Simulation results show that the algorithm is efficient to balance the energy consumption among nodes.