Research On Several Key Technologies Of Wireless Sensor Networks

The fundamental task of the wireless sensor network is to quickly and accurately access valuable information in the physical world. However, sensor nodes in wireless sensor networks are severely constrained by the limited computing power, limited storage capacity and limited communication capabilities. Therefore, energy efficient is the most important issue of concern in wireless sensor networks. In this paper, three key technologies of wireless sensor networks are studied, including routing protocols, data aggregation and network security technology. The main purpose is to optimize network structure, save the network energy, improve energy load balancing of nodes in the network, prolong the network lifetime, improve network security and ensure the reliability of the network.The characteristics of clustering network structure and the existence of some problems are analyzed, combined with the advantages of tree network structure, we proposed a tree-based and cluster-based hybrid structure of the routing algorithm. Using the strategy of minimum spanning tree to organize the cluster head nodes of the network into a tree structure to form a new routing. Algorithm can optimize the number of nodes which communicating directly with the base station, to reduce the energy consumption of cluster head nodes, and improve energy efficiency and prolong the lifetime of nodes.The characteristics of distribution density of nodes in a larger network are analyzed, in this case, there will be a large number of redundant nodes in the network. And then, the methods to determine redundant nodes are introduced, a cluster-based division method for subset of monitoring nodes and a scheduling algorithm for cluster head nodes are proposed for the network. The main ideas are as follows:when clustering is completed, according to the distribution of cluster head nodes to compute the coverage of nodes, and according to the determining method of redundant nodes to divide the cluster members into some subsets. Each subset of monitoring nodes take turns to work in accordance with the scheduling rules. So that can reduce the number of nodes which sending data in each round, save the energy consumption of nodes and prolong the lifetime of the network.For the problem of reliability of data aggregation in wireless sensor networks, the temporal reliability and spatial reliability of data aggregation are described. Then, an adaptive temporal and spatial reliability data aggregation algorithm is proposed, its main ideas are:to control the spatial reliability by adjusting the number of source nodes in this cluster, and to control the temporal reliability by adjusting the sending data frequency of the source nodes. Algorithm using the observed reliability of features of the events in the network to be gradually adjusted to achieve the desired reliability of data aggregation. To optimal energy consumption of the network under meeting the monitoring requirements.The fault diagnosis problem in wireless sensor networks is introduced, and a cluster-based real-time fault node diagnosis algorithm is proposed, which can ensure the efficiency and accuracy of fault diagnosis in the network. The main idea of this algorithm are:when the clustering is completed, each cluster head implements fault diagnosis, algorithm using a comparison-based method to test results to determine whether the node is a fault one. Each cluster head can diagnosis their members in parallel in the network. Algorithm simplified the complexity of fault diagnosis algorithm, reduced the diagnosis time, improve the efficiency of fault diagnosis, and improve the energy consumption and reliability of monitoring.Finally, a summary is written for the research work, and the innovations as well as the future work are introduced.