Research Of Wireless Sensor Networks Topology Control And Optimization Based On Energy-saving And Fault-tolerant

Due to the poor deployment environment and the lack of energy for nodes,coverage and energy constraints become the bottleneck for the development of wireless sensor networks.In addition,node failure will also cause the change of topology and accelerate the uneven energy consumption of topology.In particular,the failure of critical nodes will make wireless sensor networks more vulnerable to deliberate attacks,which results that a larger scale topology cannot work.To solve the problem of low energy efficiency caused by coverage redundancy,poor topology fault tolerance and weak resistance to intentional attacks in wireless sensor networks,this paper starts with coverage energy-saving deployment algorithm.Then the balance of topology energy consumption and fault tolerance are studied.Finally,failure of critical nodes after topology construction in wireless sensor networks is analyzed.The specific research works are as follows:Firstly,to solve the problem of nodes energy limitation and coverage redundancy of wireless sensor network,the fitness objective function is constructed by considering two factors that coverage and energy consumption.Taking the coverage energy fitness function as the objective function,this paper uses the improved discrete gray wolf optimization algorithm to optimize the sleep active state transition scheme of wireless sensor network nodes,and finally obtains the optimal distribution of node positions.Then the optimal deployment of coverage and energy saving of wireless sensor network nodes can be realized.These provide the basis for the construction of the energy consumption balance topology of wireless sensor network with fault-tolerant.Secondly,on the basis of covering energy-saving deployment,considering the importance of good topology structure,a fault-tolerant weighted scale-free topology with high agglomeration coefficient is constructed.The relationship between node energy consumption and residual energy and load is studied,and the node lifetime model is established.By analyzing the relationship between clustering coefficient and fault tolerance,the topological evolution mechanism of triangle connection is introduced.Then,the node lifetime model is taken as the edge weight.By using edge weight to control node strength,a weighted topology control algorithm of wireless sensor network is proposed.The weight distribution and degree distribution of this algorithm meet the power characteristics and the energy consumption is balanced.Through controlling the energy parameters,the wireless sensor network topology that meets the requirements of energy consumption balance and fault tolerance is evolved.Thirdly,based on the topology generated by the energy consumption and balanced fault-tolerant weighted topology algorithm,this paper analyzes the factors that affect node’s importance,and selects two factors,clustering coefficient and betweenness,to represent the local and global attributes of nodes.The function models of edge clustering coefficient and edge betweenness are established respectively by using the function expression of node clustering coefficient and node betweenness.In addition,the interaction between nodes and connecting edges is considered.Finally,a critical node decision index with local and global attributes is obtained.Theses lay the foundation for the design of the critical nodes’ protection methods.Finally,after the key nodes are determined,this paper considers the problem that the critical nodes are extremely vulnerable when they are faced with intentional attack.Firstly,the relationship between the amount of defense resources and node vulnerability is analyzed.The critical node judgment index is introduced into the network risk model as the weight factor.Then,an optimization allocation model of wireless sensor network’s defense resource is established by taking the minimization of network risk as the goal.The optimization model is solved by using Lagrange multiplier method and relaxation theorem of dual theory.Finally,the optimal allocation scheme of defense resource of critical nodes in weighted topology is obtained,and the ability of network to resist intentional attack is enhanced.This paper provides guarantee for protecting critical nodes and further improving the energy-saving topology of wireless sensor networks withe fault-tolerant.