Research On Wireless Sensor Network Fault Tolerant Topology Control Algorithm For Node Failure

Wireless sensor networks(WSNs) are self-organizing networks with limited energy. They are usually deployed in remote areas which people generally cannot reach. The nodes in WSNs often become failure due to energy depletion and environmental damage. The failure nodes have seriously effect on the network performance. And the cascading failure easily appears in the WSNs scale-free network, which can lead to the network paralysis. Then it is significant for the research on fault-tolerant topology control about node failure. The specific research contents in this paper are as follows:In order to solve the energy depletion and random failure in WSNs deployed in remote and relatively mild environment. We firstly analyze energy depletion and random failure. And the energy depletion model and the random failure model are established. Then a fault tolerant topology whose degree distribution can be adjusted is built. Based on this topology built and the energy depletion model and random failure model, the fault tolerant topology under energy depletion and random failure is analyzed. After that, according to the conditions that network requirements, the optimal parameter value is obtained. At this time, the network lifetime is longest. Then the optimal parameter is substituted into the fault tolerant topology whose degree distribution is adjusted. Then we can obtain a WSNs fault tolerant topology effectively tolerant energy depletion and random failure.In order to solve the problem that dangerous harsh environment can lead to a larger number of random failure node in WSNs. We choose scale-free network structure to tolerant the large scale of random failure nodes. While the energy of the node with lager degree in scale-free network run out quickly. So we present a WSNs fault tolerant control algorithm which can effectively tolerate energy depletion and a large number of random failure. We firstly built the comprehensive failure probability model. According to the network lifetime and the integrated fault tolerance, the relationship between the network node degree and the maximum node degree is obtained. Then based on the scale-free characteristics, the expression about the network node degree and the maximum node degree is acquired. Then we can obtain the optimal value of network maximum node degree. And the fitness function about network maximum node degree is established. Last, a WSNs scale-free topology effectively tolerant energy depletion and a larger number of random failure can be obtained.In order to solve the cascading failure in WSNs scale-free topology, we built the cascading failure model applied to WSNs. Then according to the cascading failure model built and the scale-free characteristics, the critical load triggering a large of cascading failure is obtained based on the probability generating function method. Then the node data traffic in the process of network operation is analyzed and the actual node load is obtained. Based on the critical load an actual load, we proposed that if the actual node load is less than the critical node load, the cascading failure can effective prevented. Based on this though, we design a cascading failure control algorithm in WSNs scale-free topology with redundant links.