Research On Range-free Localization Algorithm In Wireless Sensor Network

In recent years, with the rapid development of wireless communication and WSN(Wireless Sensor Network) has become the hottest area of research and is widely used. However, the data of sensor nodes has no practical significance for WSN if there has no incorrect location of sensor nodes. So it is very important for the application of WSN to obtain accurate location of sensor nodes.In addition, localization technology is one of the key support technology of wireless sensor networks.In the paper, the DV-Hop algorithm is an attractive option for the localization of nodes in the wireless sensor network due to its simplicity. However it suffers from poor accuracy. To solve the problem of low positioning accuracy in base DV-Hop,a new localization algorithm based on hop count a correction is proposed, but The improved algorithm is also insufficient.Therefore in this paper we present a novel algorithm which based on hop distance correction to enhance the accuracy of DV-Hop algorithm. The main idea of the improved algorithm is modified hop distance. Firstly it uses the theory of base DV-Hop algorithm to estimate position of the anchor nodes which are already known, thus the estimation error of anchor nodes is obtained. Secondly it use linear search algorithm to find the optimum correction of the hop size, so we obtain the best hop size and get the correction of the hop distance between the unknown node and anchor by fixed minimum hop count and the best hop size.Lastly the location of the unknown nodes is estimated with the modified hop size using multilateral measurement method for the position of unknown node coordinates. The simulation experiment of the improved algorithm is got through by MATLAB.we compare the performance of the original DV-Hop algorithm, HCDV-Hop algorithm and the improved algorithm of varying node numbers, anchor numbers and communication radius. The results show that the proposed algorithm has better performance in the localization precision and coverage rate than the original DV-Hop algorithm and the HCDV-Hop algorithm.