Some Issues On Distributed Detection In Wirelesss Sensor Network

Wireless sensor network(WSN)is a kind of multiple hops self-organizing network system which perceive data,acquire and process the data that obtained from the network coverage area by wireless communication.WSN is deployed in monitoring area within a large number of low-cost micro sensor nodes,which widely used in military,environment monitoring,health care and other fields.The distributed target detection technology is one of the important applications of the wireless sensor network technology.In the distributed detection system,sensors send summaries of their measurements and observations to the fusion center instead of the raw measurements.It gains because of its limited use of resources and bandwidth.Also,it reduced the detection performance require and the price of the single nodes.This paper mainly studies the distributed single target detection problem under the wireless sensor network.The classical theory of distributed detection is introduced,we analysis the Bayes criterion and the Neyman-Pearson criterion and under the rule of Bayes theorem and the rule of Neyman-Pearson,the optimal decision rule of local sensors and the fusion center was given.After that,this paper mainly studied the tree architecture of the sensor network.Under the assumption that sensor observation are conditional independence of each other and the sensors have identical detection performance,we study the detection performance of the m-ary relay tree.We derive upper and lower bounds for the Type I and II error probabilities at the fusion center as explicit functions of N in the case where nodes and links fail with certain probabilities.The obtained bounds characterize the asymptotic decay rate of the error probability as N goes to infinity.Naturally,this decay rate is not faster than that in the non-failure case.Further,we derive a necessary and sufficient condition in terms of the decay rate of the node and link failure probabilities at each level to ensure that the error probability of the tree with node and link failures decays as fast as that of the tree with no failures.Next,in view of the practical application,due to the influence of the changing of working environment and a variety of other uncertain factors,the detection performance of the nodes maybe not are exactly the same as each other,so we proposed a fusion algorithm with confidence-weighted.When the weights of the nodes are unknown,we use a feedback algorithm to estimate the weights,the simulation example of the weight estimate algorithm prove the effectiveness of the algorithm.Finally,we verify the effectiveness of the confidence-weighted algorithm.by using a simulation to compare the detection performance of the system under the fusion rule with confidence-weighted and under the fusion rule without weight.