| With the rapid development of China's high-speed railway, the growing attention is paid over the safety and reliability of train operation. Comprehensive inspection train is the most effective and important tool to protect the safety of train operation, which integrates the various subsystems of the wheel and rail, track, catenary, communication, signal detection, and is also responsible for over 200 trains running technical parameters measurement. If real-time results of these tests can be get, real-time monitoring and remote fault diagnosis also can be achieved, train scheduling decisions based on actual data which can avoid the occurrence of train accidents will be greatly improved. However, due to the complexity of the measurement and vast volume of data, real-time transmission of business data proves to be difficult, thus causes security risks in the railway system. As to comprehensive testing of data transmission, a novel method which combines wireless transmission of 3G networks and WLAN networks is proposed. The introduction of 3G will enhancement data transmission performance, however due to the high speed of train running, a lot of sudden emergency services are still unable to get effective transmission. Therefore, the objective of this paper is to present a data transmission interface protocol in order to various transmission needs. Based on data analysis, classification, processing, the proposed method uses different priority queuing strategy to meet the transmission needs, and optimize the service quality of the transmission system. Thus, the transmission interface protocol is the core and key technologies to realize the effective data transmission.Firstly, feasibility of application of 3G technology in communication system has been analysis. Then considering technical characteristics of the WLAN network, a novel line - point Train-Earth wireless transmission method is the proposed based on the combination of 3G and WLAN.3G network is responsible for the transmission of lightweight service data, while WLAN is responsible for the transmission heavyweight service. According to the transmission test on the actual performance, network bandwidth in the high-speed mobile environment is still the bottleneck of the car system.In order to meet the transmission requirements of different service and improve the system's reliability and efficiency under the condition of limited bandwidth network, a design of data transmission interface based on the train service is proposed. The interface protocol firstly proposes a detail database scheme structure design according to the classification of different service departments'data. By analyzing the character of different service, a strategy of different priority adjustment according to the multiple kinds of service type is proposed and the system's transmission performance is optimized. We select the optimal transmission tasks using the zero-one integer programming method when the train is closing the station. By this way, the optimized transmission task will be selected by the system under the condition of limited train parking time. Meanwhile, the transmission interface has contained the compression process, further improving the system'transmission efficiency.Finally, in a real environment, the data transmission interface protocol is tested. Statistical analysis based on the large number of test results indicates that the data transmission interface is able to meet the transmission requirements of different needs. Validation and necessity of the data transfer interface is well proved. At present, the transmission interface has been successfully applied the High-Speed Comprehensive inspection train which operate in stable and reliable condition. |
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