摘要
当未来第5代移动通信系统(5G)的大规模多天线(LSMA)系统应用在高速铁路车地通信基站时,天线沿铁轨平行布置,基站根据列车位置选择最近的若干根道旁天线组成备选集进行信道估计,并将有限个射频链分配给其中信道最好的若干根天线组成的优选集。由于信道的时变和强视距特性,不同天线的信道信息发生不同程度的延迟,传统的从信道估计信息中挑选增益最大天线的选择算法频谱效率不高。本文提出一种基于权重预处理的天线选择算法,只需要对估计的信道增益进行权重预处理就能有效地提高天线选择算法的平均频谱效率。在本文提出的方案中,首先推导了高铁时变信道下天线选择算法的平均频谱效率性能上限的理论值,然后根据同一天线不同时刻信道状态间的时间相关性,对信道增益进行权重预处理,再从处理后的备选集中选择优选集。分析结果表明,经过权重预处理的算法平均频谱效率在列车高速运行时稳定高于不进行预处理的传统天线选择算法的频谱效率,在高信噪比情况下,能提高0.4bit/s/Hz。
The Base Station（BS）antennas are deployed along the rail track and those close to the train are selected to measure the channel and compose the Alternative Set（AS）,when Large-Scale Multiple Antenna（LSMA）system of the 5th generation mobile telecommunication system（5G）is applied to the onboard/ground communication BSs of high speed railway.A limited number of Radio Frequency（RF）chains will be allocated to the AS antennas with the best channels,to constitute the Preferable Set（PS）.Due to the time-varying channel with strong line-of-sight path,the channel state information（CSI）of different antennas will be subject to different extent of delay,thus the spectral efficiency（SE）of the conventional antenna selection algorithm which selects antennas with the highest estimated channel gains will degrade.An antenna selection algorithm based on weighting pre-processing is proposed.By weighting pre-processing on estimated channel gains,the average spectral efficiency of the antenna selection algorithm will effectively increase.The SE theoretical upper bound of antenna selection algorithms under the scenario of time-varying channels of high speed railway is derived and then the estimated channel gains are weighted based on the time correlation between different moments of channel states of the same antenna,before the PS is chosen from the AS.Analysis shows that the proposed algorithm achieves 0.4bps/Hz more SE than the conventional algorithm when the train speed and signal-to-noise ratio（SNR）are high enough.
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2016年第1期65-69,共5页
Journal of the China Railway Society
基金
国家重点基础研究发展计划(973计划)(2012CB316100)
国家自然科学基金(61471303
61032002)
中国铁路总公司科技研究开发计划(2013X016-A)
关键词
频谱效率
天线选择
高速铁路
预处理
大规模多天线系统
spectral efficiency
antenna selection
high-speed railway
pre-processing
Large-scale multiple antenna systems
