日趋重要的高速移动工具,如高速铁路、无人驾驶飞机等,大多都处在开阔地带.由于视距传播的存在,瑞利衰落模型已经不能很好地描述该环境下的信道情况,而莱斯衰落信道模型由视距分量和多径分量组成,更能准确地表述上述信道变化.基于此模型,在大规模天线系统下,在已存在的基于叠加训练序列信道估计方法的基础上,提出了改进的信道估计方法和对应的解码方法.改进后的信道估计方法分为直射分量已知和未知两种情况,分别推导了相应的信道估计公式和解码方法.数值仿真结果验证了本文所提方案性能的优越性.%The high-speed mobile transportations,such as high-speed rails,pilot-less airplanes,are mostly in the open areas.Due to the existence of line of sight (LOS) propagations,the Rayleigh fading model can not describe the channels very well in these environments.The Rice fading channel model is constituted of a LOS component and a multiple-path component,which can characterize the channels more accurately.Based on the Rice model,the improved channel estimation methods and corresponding decoding methods were proposed based on the superimposed training sequences for massive multiple input multiple output (MIMO) system.The improved channel estimation methods were divided into two cases:the LOS component was known to the receiver and the other was unknown.The numerical simulation results show that the superiority of the proposed methods.
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