Railway Facility Security Monitoring Wireless Sensor Network Topology And Routing Studies

The development of high-speed railway increases the demand for the safety of train traffic environment, Wireless Sensor Network technology is introduced to real-timely monitor the security of important railway infrastructures. In this paper, clustering algorithm and routing algorithm are proposed to improve the nodes'energy efficiency and extend the lifetime of Wireless Sensor Network for Railway(WSN-R).Energy oriented cooperative clustering algorithm is proposed to balance the energy consumption of nodes in WSN-R, which can avoid the problem of network lifetime reduction arising from low energy nodes' rapid death. The values of nodes'residual energy, node degree and the distance to sink node are normalized, nodes cooperatively calculate their Trust Values by these normalized values to run for the cluster heads, cluster head rotation mechanism evenly spreads the load of cluster heads to the appropriate nodes. The moderate node degree of cluster node can reduce the communication cost in cluster, and the appropriate distance between cluster node and sink node decreases the cluster head's communication energy consumption. All of these achieve the purposes of balancing network energy consumption and extending network lifetime.Concentric circles tree based routing algorithm is proposed to improve the efficiency of data forwarding and usage of network energy. Cluster heads can communicate with the sink node with the optimal power by distance prediction. The nodes within the cluster are divided into different routing levels by cluster head, and the inner nodes should forward data of outer node. With this routing rule, a concentric circles tree whose root is the cluster head is formed, thus enhancing the efficiency of data forwarding to cluster node. The connectivity of network and multi-path routing are guaranteed by nodes through power controlling, and the data can be transmitted in a multi-hop fashion within the cluster. Meanwhile, to avoid the death of nodes with low energy, whether a node forwards other nodes'data or not is determined by residual energy of itself. This decreases network energy consumption, improves energy efficiency and extends the network lifetime.Finally, energy efficiency, consumption balance and network lifetime of network nodes are researched and analyzed by OPNET simulation tool. And the simulation results verified the performance of topology algorithm and routing protocol in WSN-R.