Sunday, March 14, 2010

Algorithms in Wireless Sensor Networks


Wireless Sensor Networks(WSNs),which integrate the sensor,micro electro mechanism system(MEMS),distributed information processing and wireless communication,become one of hot research topics in the current Information Technology field.As a result of its inherent advantages,such as self-organization,wide coverage,high fault-tolerance and high accuracy measurements,as well as the features of low cost,low power,flexible deployment etc,the WSNs are applied ranging from the military areas to the abundant civil areas.The dissertation deeply studied the localization and target tracking problems in wireless sensor network,including node self-localization,the target tracking problems and so on. Based on Distributed predictive tracking(DPT) algorithm,Dynamic cluster predictive tracking (DCPT)algorithm is presented which improved the accuracy of target tracking and network life.Track the target by waking up the nodes in next one-hop radius.With moving of target, the cluster structure has also been constantly changing to avoid unnecessary energy consumption by waking up node blindly.The main contents of dissertation are as follows:(1) Optimize the cluster structure and operation mechanism.Improve the positioning accuracy of target through increase the number of node in cluster to acquire more information of target,the precision and accuracy of target predictive increased corresponding.To avoid network 'black hole',algorithms select the node full of the most energy as the cluster-head node,so as to achieve balanced energy consumption and improve the network life.(2) In positioning process,calculate the objective's specific location in the way of introducing the target signal strength as a weighting of 'centroid',so that further improve the tracking accuracy.(3) Location prediction method make use of macro-prediction and micro-prediction which combines a double prediction method to forecast the target location of the next time, start the forecast position node in the moment of objective leaving this cluster,which reduce the probability of missing of target.(4) Taking into account the various unforeseen circumstances,algorithm set up exception handling which Enhance the robustness of the system.Such as the target missing,cluster head death,etc. The experimental results show that,the half life of DCPT is higher about 30%than that of DPT,positioning algorithm proposed in this paper under the same conditions was significantly superior to the literature of the location algorithm.