The Train Communication Network Characteristic Simulation Research

The train communication network, which is the neural system of train, connects the various of communication equipment. It monitors, controls and diagnoses the equipments of train. The performance of train communication network is great significance to the train's safety, reliability and stabilization. At present, the researches on the train communication network characteristics are mainly based on the real network tests or the network test platform. But all of these methods are not only takes long time, but also increases the costs. Therefore, analyzing and optimizing the network performances by building the simulation model of train communication network is better than the former methods. Now, the train network simulation researches are few and the models of this kind of network are not accurate. In this paper, the practical train communication network is built, and the simulation results are analyzed, the train communication network based on Industrial Ethernet network is also built here.Firstly, the train communication network technology is outlined, and the actuality of CAN-bus and Industrial Ethernet network are analyzed. The common network simulation software are described, especially the characteristic and use of OPNET. The various of train communication network topology and its characteristics are analyzed. The simulation tool is selected after considering the features of train network structural and simulation software.Then, CAN bus technology is described in detail. The network topology model of Nanjing subway's train is set up by using the OPNET. The model is divided into three levels, the network filed, node filed and process field. The real parameters are analyzed based on the actual characteristics of subway train communication network. The result of simulation shows the consistency with the actual characteristics of the train. The characteristics of normal network status, the influence of communication equipment status and the interval of different packets are analyzed. The result shows that CAN bus has the good real-time and reliability in the traditional and small amount of data communication network.Finally, the high-speed train's communication network based on industrial Ethernet is studied, and the simulation model is built based on OPNET. By analyzing the characteristics of train network data, the mathematical model is setup and data are classified. The influences of video monitor data, equipment status data, command and control data, fault data of the train communication network were analyzed in the 100M and 1000M industrial Ethernet. At the same time, the network characteristic is analyzed with the different bandwidth Ethernet in the worst case. The results show that,1000M Industrial Ethernet can meet the real-time and reliability in train communication network. Therefore, the high-bandwidth Ethernet provide a solution for the large amounts of data and more intelligent devices to achieve high-speed train network communications.