Title
Channel Estimation With Reconfigurable Intelligent Surfaces—A General Framework
Abstract
Optimally extracting the advantages available from reconfigurable intelligent surfaces (RISs) in wireless communications systems requires estimation of the channels to and from the RIS. The process of determining these channels is complicated when the RIS is composed of passive elements without any sensing or data processing capabilities, and thus, the channels must be estimated indirectly by a noncolocated device, typically a controlling base station (BS). In this article, we examine channel estimation for passive RIS-based systems from a fundamental viewpoint. We study various possible channel models and the identifiability of the models as a function of the available pilot data and behavior of the RIS during training. In particular, we will consider situations with and without line-of-sight propagation, single-antenna and multi-antenna configurations for the users and BS, correlated and sparse channel models, single-carrier and wideband orthogonal frequency-division multiplexing (OFDM) scenarios, availability of direct links between the users and BS, exploitation of prior information, as well as a number of other special cases. We further conduct simulations of representative algorithms and comparisons of their performance for various channel models using the relevant Cramér-Rao bounds.
Year
DOI
Venue
2022
10.1109/JPROC.2022.3170358
Proceedings of the IEEE
Keywords
DocType
Volume
Channel estimation,direction of arrival (DOA) estimation,intelligent reflecting surface,massive multi-input–multi-output (MIMO),reconfigurable intelligent surface (RIS).
Journal
110
Issue
ISSN
Citations 
9
0018-9219
1
PageRank 
References 
Authors
0.34
53
5
Name
Order
Citations
PageRank
A. Lee Swindlehurst16429455.83
Gui Zhou252.77
Rang Liu313.72
Cunhua Pan4105977.17
Ming Li538837.81