The Research And Implementation Of The Space Time Block Coding In LTE System Under The High-speed Railway

LTE is the evolution of the3rd Generation telecommunication, it improves and enhances the air interface of the3rd Generation telecommunication, it can also bring higher rate, more simple technology and enhanced mobile broadband experience. With the advantage of flexible spectrum, the seamless interoperability with existing technology, and the low cost of network deployment and management, LTE has become the common choice of the world’s leading operators with some "4G" feature, normally be considered as "quasi-4G" technology.The current railway digital mobile communication system has using the GSM-R system. With the direction in the evolution of GSM-R, the International Union of Railways(UIC) has made it clear that3G technology is not applicable to the railways, GSM-R is not coming transited to3G, but directly evolved to the "quasi-4G" of LTE-R technology. The evolution of LTE-R is an inevitable trend in the development of GSM-R, the next generation mobile communication LTE-R railway railway will provide voice message, video surveillance, mobile multimedia services, such as large amounts of data. Compared with the public mobile communications network, the railway mobile communications network has more stringent requirements of public safety and reliability, the quality of communication services to the communications system and other factors posed a serious challenge to the security and safety of railway operations depends on whether it can provide secure and reliable communications for the train system, such as provides secure transmission channel for train scheduling data.Firstly, we studied the physical layer protocol process of LTE, the physical layer key technologies such as OFDM and MIMO, studied WINNER D2a channel model which is suitable for high-speed railway environment, we also analyzed the classical Space-Time Block Coding, Layered Space-Time Coding, Space-Time Trellis Coding and other coding techniques, Studied the classical algorithm of carrier synchronization, symbol synchronization, frame synchronization, channel estimation and diversity reception for LTE transceiver. After that the paper is discussed in detail about the architecture of USRP+Labview software radio platform, workflow, performance characteristics, etc., and implements a LTE transceiver based on the platform. Finally we used the R&S FSQ to test the function and performance of the transceiver. Test results shows that the LTE transceiver with good performance, can satisfy the requirements of the system.