摘要
大规模多输入多输出(MIMO)技术作为5G移动通信中的关键技术,极大提高了通信容量,是轨道交通通信的重要发展方向。在真实的地铁隧道环境中针对3.5 GHz与5.6 GHz频段,对32×32的大规模MIMO系统进行了信道测量。根据测量数据,分析了地铁隧道中大规模MIMO信道特性。发现5.6 GHz频段的路径损耗指数略低于3.5 GHz频段。通过对比极化交叉率,发现拱形隧道内对+45°极化与水平极化有更强的去极化特性。隧道内信号的均方根时延扩展(RMS-DS)普遍分布在10 ns以内。此外,发现信道容量随收发距离的增大逐渐减小,3.5 GHz频段时32×32的MIMO信道容量为54.64 bit/s/Hz,略高于5.6 GHz频段时的53.35 bit/s/Hz。并且发现当天线阵元的极化方式与信道极化特性相匹配或阵元数目增加时,均会引起信道容量的增加。这些发现可以对未来地铁隧道中大规模MIMO技术的应用提供依据。
Massive multiple-input multiple-output(MIMO)technology,as a key technology in 5 G mobile communications,greatly improves communication capacity,and is an important development direction for rail transit communications.In this paper,the channel measurement of the 32×32 massive MIMO system is carried out at 3.5 GHz and 5.6 GHz frequency bands in a real subway tunnel environment.According to the measurement data,the characteristics of the massive MIMO channel in subway tunnels are analyzed.It is found that the path loss index of the 5.6 GHz band is slightly lower than that of the 3.5 GHz band.By comparing the polarization crossing rate,it is found that the arc tunnel has a stronger depolarization characteristic for+45°polarization and horizontal polarization.The root mean square delay spread(RMS-DS)of the signal in the tunnel is generally distributed within 10 ns.In addition,it is found that the channel capacity gradually decreases with the increase of the transceiver distance.The 32×32 MIMO channel capacity at 3.5 GHz frequency band is 54.64 bit/s/Hz,which is slightly higher than the 53.35 bit/s/Hz at 5.6 GHz frequency band.And it is found that when the polarization mode of the antenna element matches the channel polarization characteristics or the number of elements increases,the channel capacity will increase.These findings can provide a basis for the application of massive MIMO technology in subway tunnels in the future.
作者
王成建
纪文莉
郑国莘
Wang Chengjian;Ji Wenli;Zheng Guoxin(Shanghai Institute for Advanced Communication and Data Science,Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication,Key Laboratory of Specialty Fiber Optics and Optical Access Networks,Shanghai University,Shanghai 200444,China;Technical Center of Shanghai Shentong Metro Group Co.,Ltd.,Shanghai 201103,China)
出处
《电子测量技术》
北大核心
2021年第15期128-135,共8页
Electronic Measurement Technology
基金
国家自然科学基金面上项目(NSFC61871261)
上海申通地铁集团有限公司科研项目(JS-KY19R031)资助。
关键词
地铁隧道
大规模MIMO
信道测量
信道特性
the subway tunnel
massive MIMO
channel measurement
channel characteristics
