| Wireless sensor network (WSN) is a kind of brand-new information collection and processing technology, it has penetrated into every field of life. As a comprehensive research direction, in recent years domestic and foreign scholars have proposed a lot of localization algorithms. Due to volume, energy, cost of restrictions,wireless sensor network node localization faces new challenges.In this paper, Research work and innovations are:Paper focuses on the researching four representative range-free localization algorithm of wireless sensor network. Their respective principles and processes are described, the strengths and weaknesses are also discussed. Centroid algorithm is simple and easy to achieve, but the deployment and density of beacon nodes would have a great influence on location accuracy. The positioning accuracy of APIT algorithm is higher, but algorithm requires wireless network has very good performance, thereby connectivity nodal density of network must be high. DV Hop algorithm has Low demand for the hardware requirements of network nodes, but it overly depends on the average distance of beacon nodes. In some experimental sites Amorphous localization algorithm can obtain very good positioning effect, it also has a high network connectivity requirements.In this paper, according to DV-Hop algorithm has high requirement for the average hop distance, we present an improved DV-Hop algorithm based on the correction of average hop distance. The basic ideas and implementation steps of the improved algorithm are given. After the average hop distance is obtained, the distance error between actual distance and estimated distance of beacon nodes divided by the least hops, using the ratio to correct average hop distance. In the calculation of the distance from a unknown node to a beacon node, using revised average every hop distance value which unknown nodes in the beacon node path to calculate.An improved DV-Hop algorithm based on the elimination of redundant path is proposed in This paper. In order to improve the DV-Hop algorithm positioning precision, adopting revised average Hop distance value to calculate. The improved algorithm are described in detail. First it finds the nearest beacon nodes to a unknown node. The actual distance from this beacon node to other beacon nodes divide by the least hops between them and average all ratio values. Finally put the average ratio value related to the beacon node and the average hop distance obtained by original DV-Hop algorithm to average. By this way to eliminate redundant path and improve the accuracy of the average hop distance.In this paper we make the simulation on MATLAB platform. The results show that the proposed algorithm Can reduce location error significantly without extral Node hardware, it has more precision to execute localize process, and improve the localization performance.This paper proposed an cooperative communication algorithm based on original centroid algorithm. The main idea of the improved algorithm is: though original centroid algorithm, some nodes of the network would be rough located. The nodes in addition to the beacon nodes choose the nearest one as their cooperative partner. Find the common neighbor beacon nodes of unknown nodes and partner nodes, using a certain mechanisms to format virtual beacon nodes. Thus unknown nodes get more information of reference nodes, positioning performance can be improved. It does stimulation experiment on the MATLAB platform. In the case of different communication radius, comparing positioning accuracy and positioning coverage of original algorithm and improved algorithm .Cooperative communication algorithm is superior to the original DV-Hop algorithm. |
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