Research On The Algorithm Of Coverage Hole Healing And Optimization For Wireless Sensor Networks

The subject of this thesis is derived from Natural Science Foundation of China named research on algorithm of k coverage for WSNs(Wireless Sensor Networks)based on homology theory.This thesis focuses on the problem of coverage hole healing and optimization.In order to solve the problem in the situation that the location of nodes and the distance between nodes are not available,a hole healing algorithm based on AOA(Arrival of Angle)and a coverage optimization are proposed.The coverage hole healing algorithm takes AOA and communication information into consideration,and guides the movement-assisted node to fix the coverage hole.The aim of this algorithm is to totally heal the coverage hole while keeping the overall consumption on movement of nodes low.The coverage optimization algorithm is aimed at making most redundant nodes sleep to decline the overall energy consumption of the network while keeping the target area totally covered.And a method is provided to realize k coverage based on the coverage optimization algorithm.The main contributions of this thesis are as follows.(1)a coverage hole healing algorithm based on AOA and homology is proposed.The algorithm is based on the coverage hole boundary which is obtained by existing algorithm.The hole healing algorithm choose repair nodes on the basis of weight of nodes,and leads repair nodes to the coverage hole.In coverage hole,based on AOA information and communication information,the repair nodes are moved to ideal position and the hole boundary is updated.The process repeats until holes in target area are completely healed.Simulation results show that the algorithm steadily increase the coverage rate to upper than 99.5%while keeping the overall moving distance low.The computation complex is O(n2),where n is the average number of neighbor nodes.(2)a coverage optimization algorithm based on homology is proposed.Getting rid of the information of location and distance.the algorithm finds out and sleep redundant nodes by simplex extension algorithm in order to construct one-level covered sets as much as possible which could total cover the target area respectively and prolong the life of WSNs.Those one-level covered sets are competent for k coverage work by collaborating with each other.Simulation results show that the number of redundant nodes slept by the algorithm is close to the upper limit while the topology characters are unchanged.The computation complex is O(n2),where n is the average number of neighbor nodes.