A Mobile Nodes Based Coverage Vulnerability Repairing Algorithm For Wireless Sensor Networks

Wireless Sensor Network(WSN)is a self-organizing network which consists of a large number of tiny,low-cost wireless sensor nodes.At present,WSN has been widely used in different fields such as military,industry,agriculture and infrastructure.WSN can be deployed in some dangerous areas that are difficult for people to reach to complete some work that people fail to do.However,when the node in the WSN fails due to its own factors or the influence of the external environment,the coverage vulnerability may occur in the network monitoring area,making it impossible to achieve comprehensive monitoring.In order to solve this problem,this thesis studies the vulnerability coverage repairing algorithm for wireless sensor network and repairs the network vulnerability by fine-tuning the position of the optimal node locally without increasing the external node.The research content of this thesis mainly includes the following three aspects:(1)In the case of unknown location of the coverage vulnerability,this thesis proposes a coverage vulnerability detection method based on network connection graph.The network connection graph is obtained by connecting each sensor node,and the position relationship between the target node and the network connection graph is used to judge whether the node is a vulnerability boundary node.After all the vulnerability boundary nodes are obtained,the location of the coverage vulnerability can be calculated.(2)A mobile node-based coverage vulnerability repairing algorithm is proposed.Considering the energy consumption of these nodes,the algorithm adopts a distributed scheme to obtain a local optimal solution.When the location of the vulnerability is confirmed,the most appropriate node is selected from the vulnerability neighbor nodes as the repair node for the coverage vulnerability.In this process,the moving distance,redundancy and residual energy of the candidate repair node are taken into account and optimized selection of candidate repair nodes is achieved.(3)In order to further optimize the network coverage ratio after the coverage vulnerability is repaired,a method for planning the trajectory of the vulnerability repair node is designed.Taking full account of the redundancy of failure nodes,the vulnerability repair node is moved to the intersection of the vulnerability neighbor nodes instead of moving to the location of the failure node.In this way,not only the effective coverage area of the vulnerability repair node can be improved,but also the coverage redundancy in the network can be effectively reduced to achieve the overall improvement of network coverage performance.The MATLAB tool is used to build the simulation experiment environment and different simulation parameters are set and selected.A series of simulation experiments are carried out to verify the effectiveness of the proposed network coverage vulnerability repairing algorithm.The experimental results show that the mobile node-based network coverage vulnerability repairing algorithm has certain advantages compared with other algorithms in terms of total moving distance,average moving distance,residual energy of nodes,effective repair area and coverage ratio.The proposed algorithm uses the existing nodes in the network to repair the coverage vulnerabilities without increasing the external nodes,which better maintains the stability and communication efficiency of the network.