Research On Cooperative Localization In Wireless Networks

With the development of wireless networks and communication technologies,a large number of nodes are connected to the network,which has created a growing demand for node localization.Cooperative localization is a process of obtaining relative localization information between nodes by using wireless signal measurement between unknown nodes,and then realizing the process of localization all nodes.It is widely used in Ad-Hoc networks such as wireless sensor networks.With the heterogeneous fusion of wireless network,in the traditional communication mode between the terminal and the base station,the peer-to-peer communication mode between the terminals and between the base stations is added,so that the introduction of the cooperative localization technology becomes possible.This paper studies and analyzes the cooperative localization technology in wireless networks,and carries out relevant theoretical research on cooperative localization,and proposed three algorithms.The specific work is as follows:(1)Aiming at the problem of how to use the limited anchor nodes to improve the localization accuracy,an anchor node selection strategy based on performance boundary analysis is proposed,which solves the problem of using limited anchor nodes to improve the localization accuracy.Based on the performance boundary analysis of Cramer-Rao Lower Bound for measuring the distance between nodes,an isotropic approximation is proposed,and based on the approximation,the optimal deployment of the anchor node network is obtained.The anchor node deployment strategy confirms the effectiveness of the past deployment of low connectivity network anchor nodes and the deployment strategy of low connectivity network anchor nodes.(2)Aiming at the different signal path fading factors in complex environment,a weighted centroid localization algorithm based on path loss factor correction is proposed to reduce the influence of signal path fading factors on localization accuracy in complex environments.The signal path fading factor of the corresponding region is estimated by the signal measurement between the anchor nodes to correct the signal path fading factor between the anchor node and the unknown node,so that more accurate distance estimation between nodes can be obtained,and then weighted centroid localization is used.To locate unknown nodes,the localization accuracy is improved compared with the traditional weighted centroid localization algorithm.(3)The essence of the dual-centered strategy of traditional MDS algorithm is studied.A cooperative localization algorithm based on extended multidimensional scaling analysis is proposed to improve the localization accuracy of traditional MDS algorithm.By studying the essence of the dual-centered strategy of the traditional MDS algorithm,a class of transformation matrices satisfying the centralization condition is derived,and the centralization matrix with better performance is found by random search,which improves the localization accuracy of the MDS algorithm.