In this paper, channel estimation techniques and phase shift design for intelligent reflecting surface (IRS)-empowered single-user multiple-input multiple-output (SU-MIMO) systems are proposed. The two novel channel estimation techniques proposed in the paper, single-path approximated channel (SPAC) and selective emphasis on rank-one matrices (SEROM), have low training overhead to enable practical IRS-empowered SU-MIMO systems. SPAC is mainly based on parameter estimation by approximating IRS-related channels as dominant single-path channels. SEROM exploits IRS phase shifts as well as training signals for channel estimation and easily adjusts its training overhead. A closed-form solution for IRS phase shift design is also developed to maximize spectral efficiency where the solution only requires basic linear operations. Numerical results show that SPAC and SEROM combined with the proposed IRS phase shift design achieve high spectral efficiency even with low training overhead compared to existing methods.

中文翻译：

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智能反射面赋能 MIMO 系统的实用信道估计和相移设计

在本文中，提出了智能反射面（IRS）授权的单用户多输入多输出（SU-MIMO）系统的信道估计技术和相移设计。论文中提出的两种新颖的信道估计技术，单路径近似信道 (SPAC) 和对秩一矩阵的选择性强调 (SEROM)，具有较低的训练开销，可以实现实际的 IRS 授权的 SU-MIMO 系统。SPAC 主要基于参数估计，将 IRS 相关通道近似为主要的单路径通道。SEROM 利用 IRS 相移和训练信号进行信道估计，并轻松调整其训练开销。还开发了一种用于 IRS 相移设计的封闭式解决方案，以最大限度地提高频谱效率，其中该解决方案只需要基本的线性操作。