Research And Implementation Of High Reliability And Real-time Perfomance For High-speed Train’s Wireless Data Transmission

With the rapid development of China’s economics, the railway building of our country changes fast as well. But there is a variety of technical problems in high-speed railway informatization which plays an important role in railway network. High-speed railway informatization has important implications for the operation and maintenance of high-speed trains. Data communications via public wireless networks make ground monitoring system keep abreast of the real-time status of the train. It can provide convenience for daily check and maintenance of train and improves the efficiency of the operation. Therefore, data transmission with wireless public network is a key technology for high-speed train’s information management.Because the wireless communication environment of high-speed train is unstable, wireless data transmission’s reliability and real-time performance is hard to ensure which has become a bottleneck of high-speed railway informatization. Wireless data transmission based on wireless public network is difficult to optimize network itself in our country’s current public network environment in short term. Therefore, we optimize the method of data transmission on application layer and control the process of sending and receiving data, so that the reliability and real-time performance of data communication can be improved. The main task in this paper can be summarized as follows:1. For the aspect of reliability, we not only provide many protective measures to ensure the reliability of data transmission, but also ensure the reliability of Wireless data Transmission Device (WTD) in unattended operation environment. Use FSM to improve software design reliability in order to provide convenience for controlling network status; use daemon process to provide software protection for wireless communication software, which avoid interruption when the communication software occurs unpredictable failure; when the software daemon process’s self-recovery doesn’t work, watchdog will make re-power and self-recovery; we use subpackage and responsible strategies to improve the success rate of data transmission in this paper.2. For the aspect of real-time, we use sending strategy based on wireless signal strength prediction to reduce the rate of data transmission failures; use data classification transmission to reduce duplication of sending public information; use data compression method to reduce size of data to be transmission, then the real-time performance of data communication will be improved. Finally, we test on high-speed trains in real environment and do a lot of simulation experiments. The experimental results show that our methods obtain a very good effect of real-time and reliability performance in ensuring railway data communication. Some optimization methods are verified in WTD developed by our laboratory and works well on high-speed trains.