Research On MIMO-STBC Technology In High-Speed Railway Environment

GSM-R technology has been widely used in China's high-speed railway lines.However,with the increase of railway services,GSM-R is difficult to satisfy more train communication information services as a narrow-band communication system.Union has proposed that high-speed railway communication will adopt the development strategy of the Railway Broadband Mobile Telecommunications System(LTE-R)technology.The LTE-R system greatly exceeds the GSM-R system in terms of network architecture,frequency point planning,network throughput,and service expansion.MIMO technology,as a key technology in the LTE-R system,can use multiple antenna designs to enhance the transmission capability,providing multiplexing gain and diversity gain to the system through spatial multiplexing techniques and spatial diversity techniques.In view of the fact that MIMO technology can effectively improve the channel capacity and reliability of the system,the thesis attempts to introduce MIMO technology into the high-speed railway environment,focusing on the encoding and decoding design and error performance of STBC.The configuration provides a reference basis for designing and parameters of MIMO technology in high-speed railway environment and has a strong practical significance.Work in this thesis mainly includes the following aspects:(1)On the basis of researching the development history of MIMO technology and space-time coding technology at home and abroad,and summarizing the research of MIMO technology in the field of railway communication,the characteristics of wireless channel and the transmission characteristics of channel The model of Okumura-Hata is analyzed.The three high-speed railway channel models of COST-207 model and WINNER II model are compared,and the WINNER II channel model and its modeling method are mainly studied.(2)Through the research on the MIMO system in high-speed railway environment,the relationship between the transmitted signal and the received signal is derived.On this basis,the channel capacity of the MIMO system is analyzed,and the channel capacity simulation is performed on the system designed by different antennas.For Maximal Ratio Combination,Equal Gain Combination,Selective Combination three kinds of diversity and technology,the best performance is selected by simulation comparison.(3)The STBC encoding and decoding scheme in the D2a scenario is studied in depth.Since the design of the STBC is mainly for the transmitting end,the Maximal Ratio Combination with better performance is selected as the receiving diversity of the MIMO system at the receiving End,thereby improving the error of the STBC.The code performance enables the MIMO system to achieve more diversity gain while reducing the reception complexity.(4)Using WINNER D2a channel as high-speed railway channel simulator,the error performance of STBC under different parameters is tested,and broadband and narrow-band interference signals are generated by band-pass filter to test the anti-interference performance of STBC.It can be seen from the test results that the MIMO system using STBC technology can use transmit and receive diversity to provide reliable and efficient data transmission,has strong adaptability to the variable speed operation of high-speed trains,and resist the deep fading caused by multipath effects effectively.