Research On Coverage Hole Healing In Large-scale Hybrid Wireless Sensor Networks

With the rapid development of the Internet of Things(Io T),the wireless sensor network(WSN),the core technology of Io T,is becoming large-scale increasingly.Coverage reflects how good an area is monitored and is one of the most crucial metrics for the Quality of Service(Qo S)of WSNs,while the network Qo S and lifetime are always degraded by the increment of coverage holes dramatically.Especially in Large-Scale WSNs(LS-WSNs),random development of thousands of sensor nodes in wide fields and big data collection of sensor nodes increase the speed of dead sensor nodes,which leads to the increment of coverage holes inevitably.In this paper,the point is research on coverage hole repairing in large-scale hybrid WSNs(LS-HWSNs).Overall,we mainly study three problems respectively,including coverage hole repairing,Confident Information Coverage Hole(CICH)healing,and CICH prediction and repairing in LS-HWSNs.To deal with these problems,we propose a number of coverage hole repairing algorithms.The achievements of this paper can be summarized as follows:(1)For the coverage hole repairing problem in LS-HWSN,based on the greedy heuristic strategy,this paper proposes a Centralized Greedy Repairing(CGR)algorithm,which can schedule mobile sensor nodes to heal coverage holes by maximizing the transmission times of a single dispatched mobile sensor node in the one-by-one method.The simulation results show that the presented algorithm can repair coverage holes effectively,while increasing transmission times,transmission data volume,and average residual energy of all dispatched mobile sensor nodes,prolonging the network lifetime,and improving the Qo S of the network.(2)For the CICH Repairing(CICHH)problem in LS-HWSN,based on the novel confident information coverage model,this paper presents a centralized dispatch repairing algorithm and distributed dispatch repairing one.Introducing the confident information coverage model to WSNs can reduce the density of sensor nodes and make the detection of CICHs more accurate.The simulation results show that,the proposed algorithms for CICH repairing can repair CICHs effectively,while improving the network Qo S and extending the network lifetime.(3)For the CICH prediction and repairing problem of LS-HWSN,based on the novel confident information coverage model,this paper proposes a CICH Predicting(CICHP)algorithm,Centralized Energy-Efficient Repairing(CEER)algorithm,and Distributed Energy-Efficient Repairing(DEER)one.The CICHP algorithm can predict the prior information of CICHs by using the energy consumption information of sensor nodes periodby-period.According to the prior information of CICHs,the two repair algorithms,CEER and DEER,can schedule mobile sensor nodes to repair CICH beforehand.The simulation results show that,the proposed algorithms can effectively heal CICHs and reduce missing sensing data and mobile energy consumption of all dispatched mobile sensor nodes,while improving the Qo S of the network and extending the lifetime of the network significantly.In addition,the proposed algorithms for CICH repairing have better performance and lower time complexity,compared with a peer centralized algorithm and distributed one,respectively.