Sub-collection. Vehicle To Communicate And The Technology And Study

The control and command system of high-speed maglev train needs to exchange important positioning information and servo data with the train. An efficient and reliable train-ground communication system is the key to insure the safety of the train. Therefore, it must achieve reliable and real-time transmission in interference and fading channel environment. In order to meet the request of the control and command system of the maglev train, special measures are used against the decline to improve the reliability of data transmission in the design of train-ground communication system, and the diversity reception technology is the most effective measure to improve the reliability of the train-ground communication system.Focusing on the development of diversity-combining module used in the train-ground communication system, the diversity-combining system as well as its key technology are discussed, and the design scheme of diversity-combining module is proposed and confirmed. Furthermore, both hardware and software of diversity combining module are developed.1. The train-ground communication system with the characteristics of the structure is analyzed. According to the demands of system design, tasks and design requirements of module are given.2. The millimeter wave multipath fading channel environment and the anti-multipath technology are introduced. On the basis of them, comparison and analysis of the combining techniques are provided, and basic principles in practice engineering are proposed.3. Based on the analysis of the requirements and characteristics of the train-ground communication system, three design schemes are researched, namely two steps combination scheme using a maximum ratio combination and a selective combination, three steps combination scheme using a maximum ratio combination and two selective combinations, two steps combination scheme only using two selective combinations. Aiming at the real environment, detailed comparison and analysis of these schemes is provided. 4. The key technologies which include time delay correction and signal-to-noise ratio estimation are researched in diversity-combining system. Data quality estimation method using bit correlation detection is proposed and verified.5. Hardware platform design for diversity-combing module is developed, schemes aforementioned are applied to practical system and FPGA design features are provided. The specific problems encountered in real testing field and the corresponding solutions are discussed. Finally, the analysis of test data in system testing shows that the module can improve the transmission performance effectively.