This paper serves as a correction to the conference version. In this work, we explore uplink communication in cell-free (CF) massive multiple-input multiple-output (MaMIMO) systems, employing semi-blind transmission structures to mitigate pilot contamination. We propose a simplified, decentralized method based on Expectation Propagation (EP) for semi-blind channel estimation. By utilizing orthogonal pilots, we preprocess the received signals to establish a simplified equivalent factorization scheme for the transmission process. Moreover, this study integrates Central Limit Theory (CLT) with EP, eliminating the need to introduce new auxiliary variables in the factorization scheme. We also refine the algorithm by assessing the variable scales involved. Finally, a decentralized approach is proposed to significantly reduce the computational demands on the Central Processing Unit (CPU).

翻译：本文是对会议版本的修正。本研究探索了无蜂窝大规模多输入多输出系统的上行通信，采用半盲传输结构以缓解导频污染。我们提出了一种基于期望传播的简化去中心化方法用于半盲信道估计。通过利用正交导频，我们对接收信号进行预处理，从而为传输过程建立简化的等效因子分解方案。此外，本研究将中心极限定理与期望传播相结合，避免了在因子分解方案中引入新的辅助变量。我们还通过评估所涉及的变量尺度对算法进行了优化。最后，提出了一种去中心化方法以显著降低中央处理单元的计算需求。