Research On Range-free Localization Algorithms Of Wireless Sensor Networks

In recent decades Wireless Sensor Network(WSN)has been the second-largest network,which plays a very important role in military and civil areas.In many areas,the precise location of the sensor nodes in WSN is the fundamental for the normal operation of the entire network.So,how to accurately obtain the sensor node position coordinates is a very important problem.WSN localization algorithm is generally divided into two categories: the first one has nothing to do with the distance between nodes,and the other is related with the distance between nodes.Compared to the latter,the former has more advantages in terms of the cost of implementation.This paper focuses on the node localization for WSNs.To the problem of the DV-Hop algorithm and the accuracy of the center-of-mass localization algorithm in the ranged-free location algorithm,several improved methods are proposed to improve the positioning accuracy.The main content is followed as:In the improvement of DV-Hop algorithm,DV-Hop is used to calculate the average hop distance and requires the number of jumps between nodes when calculating the distance between nodes.This leads to a large estimated distance error.So,an appropriate error correction function of the distance between nodes is introduced to reduce the difference between the estimated distances between nodes for positioning accuracy.The experimental results show that the localization accuracy of the algorithm is improved.For the localization accuracy,a particle swarm optimization algorithm is used to optimize the iteration of DV-Hop algorithm.We give a modified algorithm to improve the positioning accuracy.The experimental results show that the localization accuracy of the algorithm is improved.In the traditional center-of-mass location algorithm,the located node adopts the traditional centroid algorithm to determine the coordinates of the surrounding anchor nodes,and then uses the anchor node which is the closest to the node to be positioned is selected from the anchor node around the node to be positioned as the center to make a square area.In this paper,we divided the area by the coordinates of all the beacon nodes to obtain a sufficient number of estimated positions for the nodes to be positioned,and all the estimated positions obtained are calculated using the centroid formula to calculate the final estimated position of the positioned nodes.The experimental results show that the localization accuracy of the algorithm is improved.