大规模MIMO系统中基于EVD半盲信道估计的导频污染研究

Pilot contamination on EVD-based channel estimation in massive MIMO systems

文中分析了天线数量有限的大规模多输入多输出(MIMO)蜂窝系统中,基于特征值分解(EVD)的信道估计的导频污染和信号扰动问题。首先,基于一个完整的多小区多用户MIMO系统(MCMU-MIMO)模型,分析了EVD方法在有限接收天线数量下,信道估计误差产生的原因:空间上天线数量有限带来的扰动、导频污染以及相关矩阵采样数的有限性。其次,推导了基于导频的信道估计方法和EVD半盲信道估计方法的信干噪比。最后,数值仿真结果表明EVD半盲信道估计值的归一化均方误差和误比特率与天线之间的关系符合文中的推导。

A novel analysis of signal disturbance and pilot contamination is proposed for the eigenvalue decomposition（ EVD） based channel estimation in massive multiple input multiple output（ MIMO） cellular system with limited number of antennas. Firstly,based on a complete multicell multiuser-MIMO（ MCMU-MIMO） system channel matrix,the reasons of transmission error in EVD-based channel estimation with finite antennas are explored ： the pilot contamination,signal disturbance caused by the limited number of antennas and the constrain of limited sample number of the correlation matrix. Secondly,a signal to interference and noise ratio（ SINR） is derived based on channel estimation method and EVD-based semi-blind channel estimation method. Finally,the derived relationship between normalized mean square error（ NMSE） of channel estimates as well as bits error rate（ BER） and the number of antennas is verified by simulations.