Research On Network Structure And Data Transmission Technologies In Wireless Sensor Networks

Wireless sensor networks (WSN) have exoteric environment, dynamic topology structure and limited resource node, which enables its security issue to be the research hotspot and difficulty point of this field. This thesis is focus on structure and reliable data transmit of WSN, and the framework is as following:To begin with, this thesis commits to designing a simple and efficient cluster-based algorithm of WSN. We firstly analyze the present cluster-based algorithms in ad hoc network and WSN, of which the most do not consider the pertinence of transmit data in each network node or reasonable data integration, i.e., data packet in same cluster can be compassed to be entirely one. However, the extent of data integration and data pertinence are closely connected to each other in a practical WSN. As a result, it is necessary to observe the partial characteristics of a cluster-system in effect to cluster-system network energy. After that,we propose a WSN cluster-system algorithm based on node station. It can be concluded that this method is highly effective and accomplishable to double the transmission speed.In the second part, we put forward a flexible cipher code project based on the cluster algorithm. This project supposes that WSN has already been equipped with effective security detection mechanism to inspect whether transducer node is captured or already consumed. WSN has the following special features, such as limited calculating ability, removeable node, large-scale disposal, self-serviced manipulation, narrow bandwidth and storied resources. All of these features plus high risk of physical attack. All of these bring great challenge on security toward unmanned operation node, thus security issues of WSN are significant. We've found that network security is related to renovation of cluster-system; low consumption, reduced calculation workload and increased security are the key to distinguish with other projects. Therefore, symmetry cipher code system is adopted in this project, which defines distribution, supply, cancellation and renovation in network.Moreover, in the third part, we study the important constituent part of reliability of WSN--- Congestion Control. A great deal of literature has been devoted to the check measurement of congestion control, in order to find precise and cheap ways for congestion inspection. When congestion will or has appeared, we should take effective measures to relieve congestion. There are many congestion strategies at the present, most of which are made by passing back information to data source node to decrease transmit data. Different control algorithm requests different mechanism to effectively release congestion. A new method of Energy Efficient Congestion Control are proposed to inspect congestion in accordance with service condition of cushion queue, and the congestion release is completed by means of establishing new transmit canals and modifying node data to higher speed rate.Finally, the last part of this thesis research heterogeneous system on internetworking of WSN between GPRS and ZigBee. We design and accomplish a mobile wireless sensor node integrated GPRS and ZigBee technology. The main function of the node is to transport information perception of relevant location in WSN, and send data to BaseStation through GPRS. Among the entire WSN, ZigBee network uploads collected data to control center in Internet by GPRS. ZigBee is designed to short distance communication while GPRS to long distance. The advantages of the two networks are trade-offed to each other; If putting both networks together, we are able to construct a complete long-distance transmission network.In a word, this thesis explores the structure problems in WSN and conducts reliable data transmission issues.