Study Of Node Localization Based On Modifying Average Hop Distance And Limited Hops Mechanism In WSN

Wireless Sensor Network (WSN) are new-type and intelligent network systems which can monitor, perceive and collect information and then process and transfer them, now WSN is a hotspot in research area. Wireless Sensor Network are widely used in all areas including military defense, smart home, health care, environmental monitoring, traffic control and so on. Without location information of the sensor nodes, the sensing data will be meaningless. So, the location information of the sensor nodes in wireless sensor network applications has an important meaning.Focusing the characteristics of the sensor network, this paper improves the range-free DV-Hop (Distance Vector-Hop) algorithm. In order to increase location accuracy and the rate of location coverage, Node Localization Algorithm based on Modifying Average Hop Distance and Limited Hops Mechanism in WSN was proposed. The main contents of this paper are as follows:First, this paper describes the basic concept and characteristics, pivotal technologies and the structure of the system of wireless sensor network. Then the paper briefly introduces the significance of the node localization. The classification, location procedure and performance evaluation standard of some classic localization algorithms are elaborated in detail.Second, Focusing the problem that DV-Hop localization algorithm using hop distance to replace beeline distance can lead big error and low location accuracy, DV-Hop localization algorithm based on weighted modifying average hop distance was proposed basing deeply analyzing and studying current localization algorithms. The algorithm makes the anchor nodes which have small errors get bigger weighted value by introducing weighted value of the average hop distance errors. Then the estimation of the average hop distance of the unknown nodes can be more accurate and achieve accurate localization.Again, this paper introduces a limited hops mechanism. So the communications volume and energy consumption can be decreased, it can also avoid cumulative errors in some degree. Furthermore, requirements that the already located unknown nodes can be upgraded to virtual anchor nodes were given in this paper, so nodes which meet the requirements can be upgraded to virtual anchor nodes and take part in localization of other unknown nodes. So, the density of the anchor nodes can be improved in the sensor network and the location results will be more accurate.Finally, utilize OPNET simulation software to simulate this algorithm. Change the simulation parameters which involved in the algorithm in the experiment, analyze and compare the experiment results. The conclusions are as follows:the location accuracy and the rate of location coverage of the Node Localization Algorithm based on Modifying Average Hop Distance and Limited Hops Mechanism in WSN which proposed in this paper are better than the traditional DV-Hop localization algorithm and the improved DV-Hop localization algorithms.