Maglev Train Cars To Digital Communication Systems To Receive And Simulation

The train-ground communication system (TGCS) serves as an information-transmitting channel linking Maglev trains and the ground control center, and its reliability and effectiveness is of crucial importance for the safe operation of Maglev Trains. During the period of"the 10th Five-Year Plan"(10FYP), the TGCS based on the analog intermediate frequency (IF) receiver reached the design standard. After entering the"11th Five-Year Plan"period (11FYP), however, the system has been confronted with higher standards for communication bandwidth and reliability, with which the former design becomes no longer compliant. Starting with a detailed analysis of the design standard for TGCS in the 11FYP period and an introduction of the latest Maglev communication developments and technologies abroad, the thesis proposes an improved design of TGCS, namely the digital TGCS based on the digital IF receiver. Treating of scheme design, argumentation, research on key algorithm module and its realization, it consists of five parts:Part I first reviews the available literature at home and abroad on the TGCS research, then compares the 10FYP and 11FYP design standard for the Maglev trial system, and finally illustrates the task and the design standard.Part II probes into the Maglev radio communication channel of millimeter wave and makes a detailed analysis and a computer simulation of the channel declining and its major parameters.Part III, in compliance with the 11FYP design standard, proposes two digital IF receiving designs: one is to first demodulate and then combine the multi-channel signals; another is to export a signal to demodulate after diversity-combining the IF signal. It compares and analyzes these two designs, considering their feasibility and possible working scenarios. It also analyzes the system's modulation and demodulation and works out a receiver demodulation scheme.Part IV analyzes the working circumstance of diversity-combining module, and presents two projects for the diversity-combining realization of the two proposed receivers. One is baseband signal diversity-combining similar to that of 10FYP; another is IF signal diversity-combining, which is still of certain difficulty to realize in terms of the IF signal synchronization and the SNR estimation. The thesis analyzes those two difficulties and puts forward two arithmetic solutions, namely a simple IF signal synchronization arithmetic based on signal correlation and an estimation arithmetic of SNR in frequency domain.At last, it analyzes the performance of diversity-combining by computer simulations.Part V demonstrates some simple experiments on the application of OFDM and TCP/IP in the system of maglev communication.