无蜂窝大规模MIMO-OTFS系统的上行信道估计方法

Uplink Channel Estimation Method for Cell-free Massive MIMO-OTFS System

无蜂窝MIMO系统中,利用大规模天线与大规模宏分集,构建以用户为中心的架构,用户可以选择多个合适的接入点来获取服务,实现均匀的用户覆盖性能,从而可以更好地满足不断增长的移动通信服务需求。研究了采用OTFS调制的无蜂窝大规模MIMO系统的上行信道估计方法。首先,根据用户的位置关系,对用户划分组群,在有限的资源下服务更多的用户;然后,设计了用户上行导频结构,研究了基于LS和LMMSE的无蜂窝大规模MIMO-OTFS上行信道估计方法。仿真结果表明,提出的上行信道估计方法在不同用户速度和不同信噪比下都能够得到稳健的信道估计结果,同时,在有多个用户的无蜂窝大规模MIMO系统中,并且每个用户在高速移动的情况下,估计的结果也能够保持较高的准确度。

In cell-free massive multiple-input multiple-output(mMIMO)systems,a user-centric architecture is constructed utilizing massive antennas and macro-diversity.This architecture allows users to select multiple suitable access points to access services,achieving uniform user coverage performance to better meet the growing demands of mobile communication services.This paper investigates the uplink channel estimation method for cell-free mMIMO systems employing orthogonal time-frequency-space(OTFS)modulation.Initially,users are grouped based on their spatial relationships to serve more users with limited resources.Subsequently,a user-specific uplink pilot structure is designed,and channel estimation methods based on least squares and linear minimum mean squared error are leveraged for non-cellular mMIMO-OTFS systems.Simulation results demonstrate that the proposed uplink channel estimation method consistently delivers robust channel estimation results under varying user velocities and signal-to-noise ratios.Moreover,in cell-free mMIMO systems with multiple users,even in high-speed mobile scenarios,the estimation results maintain high accuracy.