Research On The Fault-tolerant Topology Based On The Theory Of Scale-free In Wireless Sensor Networks

The Wireless Sensor Networks (WSNs) which are deployed in the bad environmentare the energy-limited network. The node failure is often caused by the energy depletionand environmental influences, and then the WSNs topologies which are built based on thetheory of scale-free have the strong fault-tolerance ability for node random failures. Andthese topologies can be better applied in the WSNs unattended environment. Therefore,the topology which is built based on the theory of scale-free is the focus of the presentstudy. Then based on constructing the mathematical model of scale-free topology, thegoals that the topologies can balance the network energy consumption, prolong thenetwork lifetime and improve the network intrusion-tolerance ability can be realized. Themain research works are as follows:Firstly, considering the limited energy of WSNs, the optimization of network lifetimebecomes the priority problem in the design of the network. Through analyzing the noderesidual energy and the load effect on the node lifetime, the node lifetime are introducedas the topology fitness factor. And then the fault-tolerant topology in WSNs which canextend the topology lifetime is put forward.Secondly, considering that the scale-free topology in wireless sensor networks has thepoor ability of intrusion-tolerance, a new scale-free topology with intrusion-toleranceoptimization model is constructed. Additionally, the two adjustment factors about theresidual energy and the node degree are introduced in the construction of the topologymodel. Then the scale-free topology whose power-law exponent can be adjusted isobtained. Finally, the power-law exponent is optimized by the network structure entropy,and its optimal value is derived. And the topology intrusion-tolerance ability is improvedby optimizing the parameter.Lastly, considering the comprehensive performance with the energy-saving andintrusion-tolerance characteristics in WSNs topology should be improved in practice, thescale-free topology with energy-saving and intrusion-tolerance characteristics isestablished based on the node lifetime and the network structure entropy from the globalperspective. However, the energy depletion and deliberate attack in this method are regarded as two unrelated processes, and this is not consistent with practical applicationsituation. Therefore, considering that the node failure in WSNs is influenced by energydepletion and external attack at the same time, the probability of the node failure isestablished. And the other scale-free topology with energy-saving and intrusion-tolerancecharacteristics is obtained.