Abstract

In this article, a novel semi-blind channel estimation scheme for Multiple-Input Multiple-Output (MIMO) communication system is studied and implemented for quasi-static Rayleigh fading channel, in which channel matrix H remains relatively constant throughout the block. Channel matrix H can be decomposed as a rotation matrix Q and down triangular matrix R. The triangular matrix R is estimated blindly using the QR-decomposition based Generalized Cholesky Decomposition method (GCD) of output covariance matrix, which exploits Independent Component Analysis (ICA) based blind source separation stochastic method, and Q is estimated from the orthogonal pilot symbols using QR-based novel approach to minimize the cost function. In this novel approach, orthogonal pilots can be decomposed as a deterministic Hermitian matrix and the upper triangular matrix using the QR-decomposition, and finally matrix Q can be estimated by using the back substitution method, which is presented in this paper. Simulations are demonstrated using the Alamouti space-time coded 2 transmitter antennas and different combinations of 2 and 6 receiver antennas to showcase the performance of the novel scheme as compared to the conventional Least Squares (LS) and Maximum a posterior (MAP) estimation schemes using the BPSK data modulation scheme. The results indicate that the novel scheme outperforms the other schemes and shows a considerably better result in terms of bit error rate (BER). Hence, the novel scheme is quite useful for solving a complex problem of semi-blind MIMO channel estimation by using the QR matrix decomposition technique. Further error analysis is presented in terms of the error covariance matrix by considering the noise for non-zero error case (practical case) as compared to zero-error case.

中文翻译：

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使用广义 Cholesky 分解和回代方法的 MIMO 通信信道估计方案

摘要

在本文中，针对准静态瑞利衰落信道研究并实现了一种用于多输入多输出 (MIMO) 通信系统的新型半盲信道估计方案，其中信道矩阵H在整个块中保持相对恒定。通道矩阵H可以分解为旋转矩阵Q和下三角矩阵R。使用基于 QR 分解的输出协方差矩阵的广义 Cholesky 分解方法 (GCD) 盲估计三角矩阵R，该方法利用基于独立分量分析 (ICA) 的盲源分离随机方法，以及Q使用基于 QR 的新颖方法从正交导频符号估计，以最小化成本函数。在这种新颖的方法中，正交导频可以使用 QR 分解分解为确定性 Hermitian 矩阵和上三角矩阵，最后分解为矩阵Q可以通过使用本文中介绍的回代方法来估计。使用 Alamouti 时空编码的 2 个发射机天线和 2 个和 6 个接收机天线的不同组合演示了模拟，以展示与使用传统最小二乘法 (LS) 和最大后验 (MAP) 估计方案相比的新型方案的性能BPSK 数据调制方案。结果表明，新方案优于其他方案，并且在误码率 (BER) 方面表现出明显更好的结果。因此，新方案对于通过使用 QR 矩阵分解技术解决半盲 MIMO 信道估计的复杂问题非常有用。