Research On Range-free Localization Technology For Wireless Sensor Network

Wireless Sensor Network(WSN) is a self-organized and multi-hop network system, which is composed by a large number of micro-sensor nodes that randomly cloth on monitoring area. These nodes has many functions, such as information collection, data processing, wireless communication and so on. It is a new technology of information acquisition, processing and transmission, which involves the sensor technology, wireless transmission technology, network communication technology and other technology. There are wide application prospects in the military and civil areas.In most applications of WSN, it makes sense that the information which nodes collect must be combined with the node position. Thus, node positioning become an necessary function, a key supporting technology in WSN. Firstly, this dissertation makes brief introduction for the rudimentary knowledge of WSN, secondly it introduces content and meaning of WSN in detail, analyses and compare some typical algorithms such as Centroid algorithm, DV-Hop algorithm, APIT algorithm, AHLos and APS based on AOA algorithm, and the dissertation focuses on DV-Hop algorithm. The DV-Hop algorithm cannot show good positioning accuracy in the network which topology and nodes distribute irregularly, according to this deficiency, the dissertation puts forward an improved algorithm based on average hop distance and estimate of distance, and after localization it processes the undersirable node and positioning error node which might exists in network.The improved algorithm is tested in the Matlab platform. The simulation results show that the improved algorithm has a better performace than the original DV-Hop algorithm in positioning accuracy and coverage rate at the irregular network environment, and enhance the positioning capability of algorithm. Finally, the dissertation summarizes and prospects the research of localization algorithm in WSN.