Simulation Of Train Communication Net Work Based On Ethernet

Train communication network is the core of the train traffic, which is responsible for the control, test of the entire train, and the collection, transmission of information. As the direction of modern train follows in the course of high speed and modernization, the train communication network systems get more and more concern and attention, especially the train communication network based on Ethernet, and it is the development direction of the train communication network.The foreign technology of train communication network is relatively mature, and has been widely applied. However, the domestic research and development in this area is relatively small, the technology is relatively backward, the research of Ethernet train is just beginning. Therefore, the research of train communication network based on Ethernet is important to independent development of the domestic train control products and breaking the blockade of foreign technology.The main purpose of this paper is to establish a model of double-bus train communication network based on Ethernet reference to current train network model, then simulate it in OPNET and improve the model. The simulation results could play a reference role in the construction of the actual network model.This paper first studies the development of domestic and international train communication network, analyses the advantages and disadvantage of Ethernet protocol and the train communication network based on Ethernet, and summarizes several methods to improve the real-time performance of Ethernet.This paper designed a double-bus train communication network model based on Ethernet. The model is implemented in OPNET software, then create a train communication network model, the node model of locomotive and carriage, process model in every node model. By running the simulation we can get network parameters, such as network delay, throughput, etc, and analyze the real-time performance of network, verify the feasibility and reliability of the model.In view of the real-time request of train communication network, the paper improve the model in a method of time-shared channel based on time synchronization protocol, and validate it by simulating in simulation software. To the control date which has a higher requirement of real-time performance, this paper use a method of adding high-priority field in date to ensure preferential transmission of control date, so as to meet the real-time performance demand of train communication network about control date. These methods above were all carried out and compared with the results without improving.Simulation results show that the train network model can translate and receive date in both of the two bus, and has a better real-time performance., it could meet the requirement of Ethernet delay. When one of the bus has fault, the system can switch to another one to receive date, so it could meet the reliability requirements of train communication network. This method of time-shared channel based on time synchronization protocol improved the real-time performance of network. The method by promoting the priority of control date could meet the demand of real-time performance of control date.