Limited Feedback in RIS-Assisted Wireless Communications: Use Cases, Challenges, and Future Directions

Fuente: arXiv
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Main Authors: Chen, Weicong, Guo, Jiajia, Cui, Yiming, Li, Xiao, Jin, Shi
Format: Preprint
Published: 2025
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author Chen, Weicong
Guo, Jiajia
Cui, Yiming
Li, Xiao
Jin, Shi
author_facet Chen, Weicong
Guo, Jiajia
Cui, Yiming
Li, Xiao
Jin, Shi
contents Channel state information (CSI) is essential to unlock the potential of reconfigurable intelligent surfaces (RISs) in wireless communication systems. Since massive RIS elements are typically implemented without baseband signal processing capabilities, limited CSI feedback is necessary when designing the reflection/refraction coefficients of the RIS. In this article, the unique RIS-assisted channel features, such as the RIS position-dependent channel fluctuation, the ultra-high dimensional sub-channel matrix, and the structured sparsity, are distilled from recent advances in limited feedback and used as guidelines for designing feedback schemes. We begin by illustrating the use cases and the corresponding challenges associated with RIS feedback. We then discuss how to leverage techniques such as channel customization, structured-sparsity, autoencoders, and others to reduce feedback overhead and complexity when devising feedback schemes. Finally, we identify potential research directions by considering the unresolved challenges, the new RIS architecture, and the integration with multi-modal information and artificial intelligence.
format Preprint
id arxiv_https___arxiv_org_abs_2506_22903
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Limited Feedback in RIS-Assisted Wireless Communications: Use Cases, Challenges, and Future Directions
Chen, Weicong
Guo, Jiajia
Cui, Yiming
Li, Xiao
Jin, Shi
Signal Processing
Information Theory
Channel state information (CSI) is essential to unlock the potential of reconfigurable intelligent surfaces (RISs) in wireless communication systems. Since massive RIS elements are typically implemented without baseband signal processing capabilities, limited CSI feedback is necessary when designing the reflection/refraction coefficients of the RIS. In this article, the unique RIS-assisted channel features, such as the RIS position-dependent channel fluctuation, the ultra-high dimensional sub-channel matrix, and the structured sparsity, are distilled from recent advances in limited feedback and used as guidelines for designing feedback schemes. We begin by illustrating the use cases and the corresponding challenges associated with RIS feedback. We then discuss how to leverage techniques such as channel customization, structured-sparsity, autoencoders, and others to reduce feedback overhead and complexity when devising feedback schemes. Finally, we identify potential research directions by considering the unresolved challenges, the new RIS architecture, and the integration with multi-modal information and artificial intelligence.
title Limited Feedback in RIS-Assisted Wireless Communications: Use Cases, Challenges, and Future Directions
topic Signal Processing
Information Theory
url https://arxiv.org/abs/2506.22903