基于OFDM技术的CBTC系统中列车速度对车地通信传输性能的影响  

Impact of train speed on communication quality in OFDM-based CBTC system

作　　者：张衡[1] 朱力 王洪伟 辛鑫 ZHANG Heng;ZHU Li;WANG Hongwei;XIN Xin(Beijing Key Laboratory of Subway Operation Safety Technology,Beijing Metro Operation Co.,Ltd.,Beijing 100035,China;National Engineering Research Center of Rail Transportation Operation and Control System,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京市地铁运营有限公司地铁运营安全保障技术北京市重点实验室,北京100035 [2]北京交通大学轨道交通运行控制系统国家工程研究中心,北京100044

出　　处：《北京交通大学学报》2023年第5期56-62,共7页JOURNAL OF BEIJING JIAOTONG UNIVERSITY

基　　金：国家自然科学基金(61973026)。

摘　　要：基于通信的列车控制(Communication-Based Train Control,CBTC)系统是一种采用先进的通信、计算机技术,连续控制、监测列车运行的列车控制系统.为了提高CBTC系统的传输效率,将正交频分复用技术(Orthogonal Frequency Division Multiplexing,OFDM)运用于CBTC系统,从OFDM系统的工作原理出发,研究了列车速度对于OFDM系统子载波非正交性的影响,并以无线局域网(Wireless Local Area Networks,WLAN)技术中的OFDM参数为例,对列车速度引起的信道相干时间变化进行了深入分析与计算.理论计算与仿真结果表明:列车速度对子载波间正交性的影响可以忽略不计;在同样报文长度、不同列车速度下,最低的传输速率并不一定能得到最低的误帧率(Frame Error Rate,FER);通信系统应该根据信道时变情况以及报文长度分别选择不同的传输速率以得到最低的FER.The Communication-Based Train Control(CBTC)system is a train control system that uses advanced communication and computer technologies to continuously control and monitor train opera-tions.To enhance the transmission efficiency of the CBTC system,the Orthogonal Frequency Divi-sion Multiplexing(OFDM)technology is applied to CBTC systems.Starting from the operational prin-ciples of the OFDM system,this study investigates the impact of train speed on the non-orthogonality of subcarriers in the OFDM system.Using the parameters of OFDM in Wireless Local Area Net-works(WLAN)technology as an example,a comprehensive analysis and calculation of the channel co-herence time variation caused by train speed are conducted.Theoretical calculations and simulation re-sults show that the impact of train speed on inter-subcarrier orthogonality is negligible.Additionally,under the same message length and different train speeds,the lowest transmission rate does not neces-sarily result in the lowest Frame Error Rate(FER).Communication systems should choose different transmission rates according to the channel time variation and message length to obtain the lowest FER.

关 键 词：CBTC 正交频分复用 信道估计 误帧率 

分 类 号：U231.7[交通运输工程—道路与铁道工程]