We consider a practical cell-free massive multiple-input-multiple-output
(MIMO) system with multi-antenna access points (APs) and spatially correlated
Rician fading channels. The significant phase-shift of the line-of-sight
component induced by the user equipment movement is modeled randomly.
Furthermore, we investigate the uplink spectral efficiency (SE) with maximum
ratio (MR)/local minimum mean squared error (L-MMSE) combining and optimal
large-scale fading decoding based on the phase-aware MMSE, phase-aware
element-wise MMSE and linear MMSE (LMMSE) estimators. Then new closed-form SE
expressions with MR combining are derived. Numerical results validate our
derived expressions and show that the SE benefits from the spatial correlation.
It is important to observe that the performance gap between L-MMSE and MR
combining increases with the number of antennas per AP and the SE of the LMMSE
estimator is lower than that of other estimators due to the lack of
phase-shifts knowledge.

本文研究了具有多天线接入点 (APs) 和空间相关的 Rician 衰落信道的实用无细胞 massive MIMO 系统，分别采用最大比值 (MR)/ 本地最小均方误差 (L-MMSE) 组合和基于相位感知 MMSE、相位感知逐元 MMSE 和线性 MMSE（LMMSE）估计量的最优大尺度淡化译码，导出了具有 MR 组合的新闭式 SE 表达式。数值结果验证了所推导表达式的有效性，并表明 SE 受空间相关性的影响。同时也观察到，L-MMSE 和 MR 组合之间的性能差距随着每个 AP 的天线数量和 LMMSE 估计器的 SE 低于其他估计器而增大，其原因是缺乏相移知识。