An Optimal Channel Estimation Scheme for Intelligent Reflecting Surfaces Based on a Minimum Variance Unbiased Estimator
Tobias Lindstrøm Jensen,Elisabeth de Carvalho +1 more
- pp 5000-5004
TLDR
In this article, the authors consider the problem of channel estimation in a wireless system with IRs and design an optimal channel estimation scheme where the IRS elements follow an optimal series of activation patterns.Abstract:
In a wireless system with Intelligent Reflective Surfaces (IRS) containing many passive elements, we consider the problem of channel estimation. All the links from the transmitter to the receiver via each IRS elements (or groups) are estimated. We show that the estimation performance are dependent on the setting of the IRS, and design an optimal channel estimation scheme where the IRS elements follow an optimal series of activation patterns. The optimal design is guided by results for the minimum variance unbiased estimation. The IRS setting during the channel estimation period mimics the discrete Fourier transforms. We show theoretically and with simulations that the estimation variance is one order smaller compared to existing methods with on/off IRS activation patterns as proposed in the literature.read more
Citations
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Journal ArticleDOI
Intelligent Reflecting Surface-Aided Wireless Communications: A Tutorial
TL;DR: This paper provides a tutorial overview of IRS-aided wireless communications, and elaborate its reflection and channel models, hardware architecture and practical constraints, as well as various appealing applications in wireless networks.
Journal ArticleDOI
Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and The Road Ahead
Marco Di Renzo,Alessio Zappone,Merouane Debbah,Mohamed-Slim Alouini,Chau Yuen,Julien de Rosny,Sergei A. Tretyakov +6 more
TL;DR: Reconfigurable intelligent surfaces (RISs) can be realized in different ways, which include (i) large arrays of inexpensive antennas that are usually spaced half of the wavelength apart; and (ii) metamaterial-based planar or conformal large surfaces whose scattering elements have sizes and inter-distances much smaller than the wavelength.
Journal ArticleDOI
Toward Smart Wireless Communications via Intelligent Reflecting Surfaces: A Contemporary Survey
TL;DR: A literature review on recent applications and design aspects of the intelligent reflecting surface (IRS) in the future wireless networks, and the joint optimization of the IRS’s phase control and the transceivers’ transmission control in different network design problems, e.g., rate maximization and power minimization problems.
Journal ArticleDOI
Channel Estimation for Intelligent Reflecting Surface Assisted Multiuser Communications: Framework, Algorithms, and Analysis
TL;DR: In this paper, the authors proposed a three-phase pilot-based channel estimation framework for IRS-assisted uplink multiuser communications, in which the user-BS direct channels and the users-IRS-BS reflected channels of a typical user were estimated in Phase I and Phase II, respectively, while the users reflected channels were estimated with low overhead in Phase III via leveraging their strong correlation with those of the typical user under the case without receiver noise at the BS.
References
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Journal ArticleDOI
Reconfigurable Intelligent Surfaces for Energy Efficiency in Wireless Communication
TL;DR: In this article, the authors developed energy-efficient designs for both the transmit power allocation and the phase shifts of the surface reflecting elements subject to individual link budget guarantees for the mobile users.
Journal ArticleDOI
Cascaded Channel Estimation for Large Intelligent Metasurface Assisted Massive MIMO
Zhen-Qing He,Xiaojun Yuan +1 more
TL;DR: A general framework for the estimation of the transmitter-LIM and LIM-receiver cascaded channel is introduced, and a two-stage algorithm that includes a sparse matrix factorization stage and a matrix completion stage is proposed that can achieve accurate channel estimation for LIM-assisted massive MIMO systems.
Journal ArticleDOI
Intelligent Reflecting Surface Meets OFDM: Protocol Design and Rate Maximization
TL;DR: In this article, an IRS-enhanced orthogonal frequency division multiplexing (OFDM) system under frequency-selective channels is considered and a practical transmission protocol with channel estimation is proposed.
Proceedings ArticleDOI
Intelligent Reflecting Surface Enhanced Wireless Network: Joint Active and Passive Beamforming Design
Qingqing Wu,Rui Zhang +1 more
TL;DR: In this paper, an RIS-enhanced point-to-point multiple-input-single-output (MISO) wireless system where one RIS is deployed to assist in the communication from an access point (AP) to a single-antenna user is considered, where the user simultaneously receives the signal sent directly from the AP as well as that reflected by the RIS.
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