Coverage Holes Discovery And Repair Algorithm Without Location Information In Wireless Sensor Networks

Wireless sensor networks(WSNs)consist of numerous micro-sensor nodes,and each sensor node can sense the surrounding environment and can monitor the occurrence of specific events in the sensing area in real time.This is the premise that a wireless sensor network can be widely used.The sensor nodes are often deployed in complex dangerous areas where people are difficult to reach,and the sensor nodes are usually battery-powered due to the cost and environmental constraints,so nodes have limited energy and difficult to replenish.With the node energy consumption,it is easy to lead to the death and loss of working ability,resulting in the emergence of undetected coverage holes in the detection area.However,the existing coverage holes discovery and repair algorithms are mostly limited to the conditions of the geographical location information of the sensor nodes,but the practical application of the node's location information is difficult to obtain.Therefore,based on the unknown location information,this paper presents the coverage holes discovery algorithm(CHDA)without the location information in wireless sensor networks.On this basis,we firstly regard the invasion distance as an important parameter to coverage holes,and propose a repair strategy for the coverage holes based on the invasion distance.When the location information is unknown,it is extremely difficult to detect the coverage holes in the monitoring area.The paper converts the discovery of the coverage holes to the discovery of the uncovered arcs,and composes the coverage holes of the uncovered arcs.In order to get the relative position information of the adjacent nodes,this paper proposes a secondary virtual mobile assisted positioning strategy.The covered arcs of the nodes can be obtained from the relative position of the adjacent nodes.And according to the intersection relationship of the covered arcs,we can get the simply covered edge arc sequence and the uncovered arcs in wireless sensor networks.A sensor node often neighbors multiple coverage holes at the same time.So we detect the minimized coverage holes by converting the polar coordinate position of the uncovered intersection points.Thus,the discovery of the coverage holes without location information is achieved.In the intrusion target detection application,in order to improve the accuracy of intrusion,we need to repair the coverage holes.And the existing algorithms to repair the coverage holes often regard the coverage ratio,node energy and other parameters as an important basis for covering holes.But this can't really reflect the characteristics of wireless sensor network in the intrusion detection application.So the paper regard the intrusion distance(Intrusion Distance,ID)as the important parameters of coverage holes repair in wireless sensor networks for the first time.In order to ensure the timeliness of detecting intrusion targets,it is necessary to ensure that the moving distance of the invasion target is less than the threshold DID of the given intrusion distance,and that the maximum distance of the coverage holes can not exceed the intrusion distance.Therefore,the maximum linear distance between any two points of the holes is chosen as the maximum allowable intrusion distance of the network.And on this basis,the paper introduces the wireless sensor network coverage holes repair strategy DID-Tor based on the intrusion distance.Finally,the experimental simulation environment is set up with MATLAB,and the coverage holes discovery algorithm and the repair algorithm based on intrusion distance are realized.And compared with the nodes with location information,the simulation results show the validity of the above two methods.