Reconfigurable Intelligent Surfaces vs. Relaying: Differences, Similarities, and Performance Comparison

By M. Di Renzo, Konstantinos Ntontin, Jian Song, F. Danufane, Xuewen Qian, F. Lazarakis, J. de Rosny, Dinh-Thuy Phan-Huy, Osvaldo Simeone, Rui Zhang and 5 more. IEEE Open Journal of the Communications Society, 2019

657 citations recorded by the source corpus.

Reconfigurable intelligent surfaces (RISs) have the potential of realizing the emerging concept of smart radio environments by leveraging the unique properties of metamaterials and large arrays of inexpensive antennas. In this article, we discuss the potential applications of RISs in wireless networks that operate at high-frequency bands, e.g., millimeter wave (30–100 GHz) and sub-millimeter wave (greater than 100 GHz) frequencies. When used in wireless networks, RISs may operate in a manner similar to relays. The present paper, therefore, elaborates on the key differences and similarities between RISs that are configured to operate as anomalous reflectors and relays. In particular, we illustrate numerical results that highlight the spectral efficiency gains of RISs when their size is sufficiently large as compared with the wavelength of the radio waves. In addition, we discuss key open issues that need to be addressed for unlocking the potential benefits of RISs for application to wireless communications and networks.

Subfields: Aerospace Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/b5a53a38e27fd68396c628358d0b92abb548687d

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Citations in the corpus

5G-Advanced Toward 6G: Past, Present, and Future (2023, background): “Compared with the conventional relay, RIS has some distinguishing features such as hardware complexity, power budget, noise, and average end-to-end SNR [117] as listed in Table II.”
Wireless Communications With Reconfigurable Intelligent Surface: Path Loss Modeling and Experimental Measurement (2019, result): “The comparison with relays was carried out in [32].”
Multicell MIMO Communications Relying on Intelligent Reflecting Surfaces (2019, methodology): “Performance comparisons between AF relay and IRS were performed in [9], [10].”
A Vision and Framework for the High Altitude Platform Station (HAPS) Networks of the Future (2020, background): “achieved through RSS is comparable to that achieved through radio relays [102], [115], [116].”
Path Loss Modeling and Measurements for Reconfigurable Intelligent Surfaces in the Millimeter-Wave Frequency Band (2021, methodology): “The coding state of the unit cells of mmWave RIS1 is chosen as follows: the coding state “0” is applied to Un,m if mod(m, 14) ∈ [1, 7], and the coding state “1” is applied to Un,m if mod(m, 14) / ∈ [1, 7].”
Reconfigurable Intelligent Surfaces: A signal processing perspective with wireless applications (2021, neutral): “The authors of [5], [22], and [23] compare RIS-aided and traditional relay-aided systems.”
An Overview of Signal Processing Techniques for Terahertz Communications (2020, background): “Passive IRSs [391], [392] are gaining most of the attention.”
Survey on 6G Frontiers: Trends, Applications, Requirements, Technologies and Future Research (2021, neutral): “Surface (SDS) and many more [163], [270].”
Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and The Road Ahead (2020, background): “In [49], in particular, the authors discuss all the advantages and disad-”
Federated Learning for 6G: Applications, Challenges, and Opportunities (2021, background): “Hence, if properly deployed, an RIS promises much lower energy consumption than traditional amplify-and-forward (AF) relays [39]–[41].”
Communicating With Large Intelligent Surfaces: Fundamental Limits and Models (2019, background): “The authors in [27] present a comparison between RIS- and relay-enabled wireless networks by discussing the”
Weighted Sum-Rate Maximization for Reconfigurable Intelligent Surface Aided Wireless Networks (2019, background): “Among them, one of the most promising applications is to improve the quality-of-service of users in the wireless communication system suffering from unfavorable propagation conditions [14]–[18].”
6G for Vehicle-to-Everything (V2X) Communications: Enabling Technologies, Challenges, and Opportunities (2020, background): “The recent work in [13] shows that sufficiently large IRSs can outperform traditional relay-aided systems in terms of throughput, while allowing nearly passive implementation with reduced complexity.”