Study On Location Algorithms In Wireless Sensor Networks

Wireless sensor network(WSN) is a multiple hops self-organizing network, which is formed by the wireless communication of some sensor nodes deployed in the detection region.It used to perception 、 acquisition and processing the information of the object in the monitoring area. And the location information in the monitoring information is crucial, the monitoring information tend to be meaningless without location information. Therefore, the research on node location technology is crucial to the application of WSN. The DV-Hop algorithm is a very typical means of WSN without need of ranging.This thesis aiming at the existing problem of DV-Hop localization algorithm, applies the the firefly algorithm(FA) and compressed sensing(CS) theory to location problem to improve the location performance. In a sum, the work of this thesis can be divided into the following aspects:(1) The thesis introduced the research status of localization algorithm for wireless sensor network. And then introduced the theoretical foundation of the localization algorithm including the basic principles and the classification. Finally the thesis introduced several common localization algorithm based on the distance and range-free respectively, at the same time, detailed introduced the DV-Hop algorithm.(2) The problem of location is essentially a optimization problem based on the distance or the measured values of path, therefore, some researchers used genetic algorithms(GA),particle swarm optimization(PSO) to optimized the DV-Hop algorithm for a better position accuracy. The experimental results show that the firefly algorithm is more effective, higher success rate than GA and PSO in the aspect of finding global optimal solution, thus having great potential in solving optimization problem. Therefore, this thesis uses FA to optimize DV-Hop algorithm to get better positioning accuracy. The positioning error of the least-square method was analyzed. And then the thesis introduced the firefly algorithm and proposed a firefly algorithm optimization based DV-Hop localization algorithm(FDV-Hop).Then the mathematical model was built with the smallest error for all of unknown nodes, and the firefly algorithm was used to obtain the optimal solution of the model. And the thesis compared the simulation results of FDV-Hop and the traditional DV-Hop at last.(3) In recent years, the compressed sensing theory is the very popular research front. And it causes attention in many fields. The CS theory can samples the signal with the sampling rate far below the sampling theorem under certain conditions. This is supposed to solve thelarge amounts of data transmission problems in the process of node location. Therefore, the thesis introduced the basic theory of compressed sensing. Then the three research emphases of compressed sensing theory were analyzed. At the same time the thesis expounded the theoretical feasibility of its application in node localization. And then the compressed sensing based DV-Hop location algorithm(CS DV-Hop) was proposed, which including constructs the measurement matrix and network model, and used the existing reconstruction algorithm to obtain the the position of the node. At last the simulation experiment and theoretical analysis was present to analyze the performance of the proposed algorithm.