Title
Training Optimization for Subarray-Based IRS-Assisted MIMO Communications
Abstract
In this article, we investigate the training optimization for multiple-input–multiple-output (MIMO)-aided Internet of Things (IoTs) systems that employ subarray-based intelligent reflecting surface (IRS). In order to overcome the nonlinear relationship between two cascaded channel matrices, the IRS can be divided into a series of subarrays, for which only an equivalent cascaded channel matrix should be estimated in each subarray. Correspondingly, the training sequence should be divided into multiple segments. By sufficiently utilizing the available statistical channel state information (CSI), either mean-square error (MSE) minimization or mutual information (MUI) maximization can be taken as the performance metric for optimizing the training sequence. A variety of fairnesses among different subarray channel estimations has been taken into account. Furthermore, in order to reduce the hardware cost of the power amplifier, we propose a two-stage training sequence structure, including a fully digital filter and a constant modulus sequence. To further reduce computational complexity, various low-complexity water-filling solutions are proposed. Numerical results demonstrate the accuracy and efficiency of the proposed solutions.
Year
DOI
Venue
2022
10.1109/JIOT.2021.3094522
IEEE Internet of Things Journal
Keywords
DocType
Volume
Channel estimation,intelligent reflecting surface (IRS),mean-square error (MSE),minimization or mutual information (MUI),training optimization
Journal
9
Issue
ISSN
Citations 
4
2327-4662
3
PageRank 
References 
Authors
0.37
0
5
Name
Order
Citations
PageRank
Hui Dai130.37
Z. Zhang214618.47
Shiqi Gong330.37
Chengwen Xing489173.77
An Jian-ping513528.23