Pith. sign in

REVIEW 8 minor 44 references

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

T0 review · 0 major / 8 minor · reviewed 2026-08-06 · deepseek-v4-flash

Pith's one-line read Limited feedback in RIS networks should be designed around three channel features the RIS itself creates, not legacy CSI.

desk verdict A competent survey with a useful taxonomy, but its 'distilled features' are regime-dependent heuristics and it leans heavily on the authors' own prior work. read the letter →

arxiv 2506.22903 v1 pith:B5AAIIQH submitted 2025-06-28 eess.SP cs.ITmath.IT

classification eess.SPcs.ITmath.IT
keywords limitedfeedbackreconfigurableintelligentsurfacechannelstateinformationstructuredsparsitybeamspacecodebookdesigndeeplearningFDDsystems
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper argues that limited CSI feedback in RIS-assisted systems fails if it is treated as an extension of conventional massive-MIMO feedback, because the RIS introduces channel properties that legacy schemes ignore: channel fluctuations tied to the RIS position, an ultra-high-dimensional sub-channel matrix at the BS–RIS link, and structured sparsity across users. The authors organize the field into two use cases: feeding back enough information to reconstruct the BS–RIS–user channel at the base station, and feeding back control instructions to configure the RIS itself. From this, they extract design principles: allocate feedback bits according to the sub-channel that dominates, exploit the shared BS–RIS channel so one user can feed back common structure for all, and build codebooks from capacitance values rather than phase shifts because the RIS phase response depends on incidence angle. A sympathetic reader would take the paper as a case that RIS feedback is a distinct problem with its own governing features, and that future schemes should be judged by how well they exploit those features.

What carries the argument

The carrying objects are the four user–RIS topologies (single/multiple user times single/multiple RIS), the cascaded BS–RIS–user channel matrix, and its beamspace projection under DFT matrices. The central identities are single-structured sparsity (different users share the same non-zero column indices of the hybrid-domain cascaded channel because the BS–RIS channel is shared) and triple-structured sparsity (the non-zero columns are identical up to a location offset and cascaded path-gain ratio). A second mechanism is two-timescale feedback, in which the high-dimensional, slowly varying BS–RIS channel is fed back once per large timescale while the low-dimensional, fast-varying RIS–user channel is fed back each small timescale. A third is the angle-dependent phase-shifter model, which makes capacitance the natural codebook dimension for RIS configuration rather than phase shift.

What would settle it

Measure the non-zero column support of the beamspace cascaded channel across many users in a rich-scattering environment with multiple interacting RISs: if the shared column indices and offset/ratio structure disappear, the structured-sparsity feedback schemes lose their overhead advantage. Equally direct is comparing CSI recovery accuracy under a capacitance-based codebook versus a phase-shift codebook while sweeping the incidence angle at the RIS; the angle-dependent model predicts a growing gap that phase-only feedback cannot close.

Watch

Extended reading notes

Core claim

The paper's central claim is that the design of limited feedback in RIS-assisted FDD systems should be guided by RIS-specific channel features rather than by end-to-end channel models borrowed from conventional systems. It classifies feedback into channel reconstruction and RIS configuration, and distills three features: RIS position-dependent channel fluctuation (which sub-channel is static versus dynamic depends on where the RIS is deployed), the ultra-high-dimensional sub-channel matrix (the BS–RIS and RIS–user links taken together create far more parameters than a standard MIMO channel), and structured sparsity (when the cascaded channel is projected into the beamspace domain, different users share the same non-zero column indices, and the non-zero columns differ only by location offset and path-gain ratio). The paper further claims that RIS configuration feedback must account for active–passive beamforming interplay, the large number of configuration parameters, and the angle-dependent phase-shift hardware, which together push codebook design toward capacitance-based codewords. These features are then mapped onto concrete schemes: adaptive cascaded codebooks, autoencoder and attention-based compression, channel customization that reshapes rich scattering into a few strong paths, shared-structure sparsity feedback, two-timescale deep-learning feedback, and learning-based adaptive RIS control.

Load-bearing premise

The design guidelines assume that the cascaded BS–RIS–user channel is well approximated by single-reflection paths with a shared, slowly varying BS–RIS channel and sparse beamspace structure; if deployments have rich scattering, fast-moving RISs, or near-field conditions, the overhead reductions are not guaranteed.

Editorial extensions

If this is right

  • If structured sparsity holds, the shared BS–RIS channel lets one user transmit the common non-zero column indices, cutting multi-user feedback overhead roughly to the per-user RIS–user part.
  • Adaptive cascaded codebooks that allocate bits by path importance beat fixed RVQ codebooks as path count grows, since the path-gain vector dimension rises with the number of paths.
  • Deep-learning two-timescale feedback (exemplified by RIS-CsiNet) produces beamforming vectors and RIS phase shifts directly from compressed bitstreams, avoiding full CSI recovery and reducing both overhead and computation.
  • Because the RIS phase response depends on incidence angle, codebooks built from capacitance values are necessary; phase-only codebooks cannot be mapped to correct element settings.
  • Near-field and active-RIS architectures invalidate far-field feedback assumptions, so new codebooks and feedback protocols are needed.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • Editorial extension: a direct test of the angle-dependent model is to measure reflected power under capacitance-based versus phase-based codebooks across incidence angles; the paper's model predicts a growing performance gap that phase-only feedback cannot close.
  • Editorial extension: the shared-BS–RIS-channel structure suggests a natural collaborative or hierarchical feedback design where the network aggregates the common channel component across users, a direction the review gestures at but does not formalize.
  • Editorial extension: if multi-reflection paths are not negligible in dense indoor or wideband deployments, the factorization of feedback overhead that supports the structured-sparsity schemes collapses, implying the design guidelines implicitly target sparse outdoor scenarios.
  • Editorial extension: the suggested integration of multi-modal information could be recast as moving from channel reconstruction to scene-level feedback, potentially reducing feedback to a few high-level descriptors rather than channel parameters.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

0 major / 8 minor

Summary. The paper is a survey of limited feedback design in RIS-assisted wireless systems. It proposes that RIS-specific channel features—position-dependent channel fluctuation, ultra-high-dimensional sub-channel matrices, and structured sparsity—should serve as guidelines for feedback design, and it classifies feedback into two main use cases: channel reconstruction (Sec. II-A) and RIS configuration (Sec. II-B). The survey reviews codebook-based, DL-based, channel-customization, and structured-sparsity methods for channel reconstruction (Sec. III), then describes three feedback protocols for RIS configuration: user-to-BS, BS-to-RIS, and user-to-RIS (Sec. IV), and closes with future directions (Sec. V). The contribution is organizational and tutorial rather than a new technical result.

Significance. The survey is timely and clearly organized; the SUSR/SUMR/MUSR/MUMR breakdown and the two-category taxonomy provide a useful framework for researchers entering the area. The paper is honest about the conditional validity of the design rules: Sec. 3.5 states that sparsity-based gains diminish as the number of paths grows, Sec. 5.2 warns that near-field channels break far-field assumptions, and Sec. 5.5 concedes that all AI-based feedback schemes have been evaluated only on simulated data. These caveats partially answer the concern that the 'distilled features' are being over-generalized. The main value of the paper lies in the synthesis of recent results; there are no machine-checked proofs, reproducible code, or new experimental data, so the assessment rests on the accuracy of the literature descriptions, which appear faithful to the cited works.

minor comments (8)
  1. [Abstract / Sec. III] The abstract lists three channel features, but the body also treats time correlation (Sec. 3.2, Sec. 4.1) and angle-dependent phase shifts (Sec. 2.2.3) as design drivers; the abstract should either add these or state explicitly that the three listed features are a representative subset.
  2. [Sec. 3.4 / Sec. 5.2] Because the structured-sparsity design rule applies only under sparse-scatterer and far-field conditions, and the near-field discussion in Sec. 5.2 concedes severe performance degradation, the paper should collect the applicability conditions of each design guideline in one place, such as a short paragraph at the end of Sec. III, to prevent readers from treating the features as universal.
  3. [Sec. 3.5] A systematic comparison table summarizing assumptions, feedback overhead, computational complexity, and applicable scenario for the methods in Refs. [21], [22], [27], [33], [34], and [29] would materially improve the survey; the prose comparison in Sec. 3.5 is useful but does not allow readers to weigh the methods side by side.
  4. [Abstract / Sec. 2.1] The term 'position-dependent channel fluctuation' is not formally defined; the body discusses how RIS placement and mobility affect channel dynamics (Secs. 2.1.1 and 2.1.2), but the abstract's phrase should be tied to a specific definition or equation.
  5. [Sec. 2.1.2] The claim that multi-reflection channels between RISs are negligible is stated without a quantitative path-loss comparison; adding a short expression for the multiplicative path-loss penalty or citing a study that quantifies the regime would make the assumption easier to evaluate.
  6. [Fig. 1] The caption of Fig. 1 lists scenario abbreviations but does not explain the row/column structure or the meaning of the arrows; please expand the caption to make the figure self-contained.
  7. [Sec. 5.2] There is a typo: 'near-filed' appears twice and should be 'near-field'.
  8. [References] Ref. [43] is an arXiv preprint; if a peer-reviewed version has appeared, the published version should be cited instead.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the article is a literature survey whose design guidelines are explicitly distilled from the cited schemes it reviews.

full rationale

This paper makes no first-principles derivation or novel predictive claim; it is an expository review. Its central organizing features, such as position-dependent channel fluctuation, ultra-high dimensional sub-channel matrices, and structured sparsity, are presented as distilled from prior work. The abstract states that these features are 'distilled from recent advances in limited feedback and used as guidelines for designing feedback schemes,' while Sec. III explicitly attributes each scheme to cited references such as [21], [22], [27], [33], and [34]. None of the load-bearing steps fits the circularity patterns: there is no parameter fitted to data and then renamed a prediction, no uniqueness theorem imported from the authors' own work to force a choice, and no ansatz smuggled in via citation. The survey instead states the assumptions on which each method rests, e.g., sparse-scatterer MUSR settings in Sec. 3.4 and slow path-direction variation in Sec. 3.5, and it concedes limitations such as near-field degradation in Sec. 5.2 and the lack of measured CSI samples in Sec. 5.5. Self-citations appear frequently, but they are examples of published schemes under review rather than unverified evidence used to close a derivation. The paper is therefore self-contained as a review and does not reduce its conclusions to its own inputs.

Assumptions & free parameters 0 free parameters · 4 assumptions · 0 invented entities

The paper relies on several standard channel modeling assumptions from the RIS literature. These are domain assumptions rather than free parameters, since no data is fitted in the review itself.

assumptions (4)
  • domain assumption Multi-reflection channels between RISs are negligible compared to single-reflection channels.
    Invoked in Section 2.1.2 to justify focusing on single-reflection cascaded channels; this may fail in certain dense deployments.
  • domain assumption The BS-RIS channel is shared across users and relatively static at the large timescale.
    Underpins MUSR and MUMR feedback sharing in Sections 2.1.3, 3.4, and 4.1.
  • domain assumption Structured sparsity exists in the beamspace cascaded channel, with shared non-zero column indices across users.
    Used in Section 3.4; depends on limited scatterers and shared BS-RIS geometries.
  • domain assumption RIS phase shift depends on incident angle and capacitance, requiring capacitance-based codebooks.
    From Section 2.2.3, based on the angle-dependent phase shifter model from [38].

how reviews work

0 comments
Cite this review

Pith. "Pith review of Limited Feedback in RIS-Assisted Wireless Communications: Use Cases, Challenges, and Future Directions." pith.science (2026). https://pith.science/paper/B5AAIIQH

@misc{pith2026250622903,
  author       = {Pith},
  title        = {Pith review of: Limited Feedback in RIS-Assisted Wireless Communications: Use Cases, Challenges, and Future Directions},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/B5AAIIQH}},
  note         = {Machine review of arXiv:2506.22903}
}
read the original abstract

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.

Figures

Figures reproduced from arXiv: 2506.22903 by the authors.

Figure 1
Figure 1. Channel characteristics in SUSR, SUMR, MUSR, and MUMR scenarios. beamforming vector and RIS phase shifts according to the received feedback information, outperforming conventional algorithms in terms of achievable rate. Ref. [35] proposed an adaptive codebook-based lim￾ited feedback protocol, improving the data rate perfor￾mance by taking into account the practical RIS reflec￾tion behavior. Although existing studies… view at source ↗
Figure 2
Figure 2. Performance of the adaptive codebook [27] and the RVQ codebook. codeword structure is consistent with the cascaded path gain’s characteristics. With a fixed number of feedback bits, the dynamic allocation of these constrained bits according to the channel distribution facilitates the creation of cas￾caded codewords. Because the adaptive cascaded codeword captures the importance of elements in the path gain vector, i… view at source ↗
Figure 4
Figure 4. When the RIS-cascaded spatial domain channel Hk, whose element denotes the channel responses of each antenna-RIS unit pair in space, is projected into hybrid spatial and angular domains channel H¯ k using the DFT matrix, different users share the same indices of the non-zero columns, which is defined as single-structured sparsity [21]. while simultaneously deploying an SVD transceiver with minimal feedback overhead … view at source ↗
Figures from the paper (2 more)
Figure 5
Figure 5. Figure 5: Triple-structured sparsity: in addition to the non-zero column indices, the beamspace cascaded channel exists absolute identity between the non-zero columns except for the location offset and cascaded path gain ratio [22]. The column height and color-coding of the pict…
Figure 6
Figure 6. Figure 6: DL-based two-timescale CSI feedback and beamforming framework, RIS-CsiNet [34]. ing feedback for the RIS configuration remains chal￾lenging due to the large number of RIS elements. As illustrated in Sec. 2.2.2, the conventional codebook￾based schemes, which are efficie…

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

44 extracted references · 43 canonical work pages

  1. [14]

    Channel cus- tomization for low-complexity csi acquisition in multi-ris-assisted mimo systems[J]

    CHEN W, HAN Y , WEN C, et al. Channel cus- tomization for low-complexity csi acquisition in multi-ris-assisted mimo systems[J]. IEEE Jour- nal on Selected Areas in Communications, 2025, 43(3): 851-866

  2. [26]

    Efficient deep learning-based cascaded channel feedback in RIS-assisted communications[J]

    CUI Y , GUO J, WEN C K, et al. Efficient deep learning-based cascaded channel feedback in RIS-assisted communications[J]. IEEE Trans- actions on Vehicular Technology, 2024: 1-6

  3. [27]

    Adaptive bit partitioning for reconfigurable intelligent sur- face assisted FDD systems with limited feedback [J]

    CHEN W, WEN C K, LI X, et al. Adaptive bit partitioning for reconfigurable intelligent sur- face assisted FDD systems with limited feedback [J]. IEEE Transactions on Wireless Communica- tions, 2022, 21(4): 2488-2505

  4. [33]

    Channel cus- tomization for limited feedback in RIS-assisted FDD systems[J]

    CHEN W, WEN C K, LI X, et al. Channel cus- tomization for limited feedback in RIS-assisted FDD systems[J]. IEEE Transactions on Wireless Communications, 2023, 22(7): 4505-4519

  5. [34]

    Deep learning-based two-timescale CSI feedback for beamforming design in RIS-assisted communi- cations[J]

    GUO J, CHEN W, WEN C K, et al. Deep learning-based two-timescale CSI feedback for beamforming design in RIS-assisted communi- cations[J]. IEEE Transactions on Vehicular Tech- nology, 2023, 72(4): 5452-5457

  6. [39]

    Overview of deep learning-based CSI feedback in massive MIMO systems[J]

    GUO J, WEN C K, JIN S, et al. Overview of deep learning-based CSI feedback in massive MIMO systems[J]. IEEE Transactions on Communica- tions, 2022, 70(12): 8017-8045

  7. [43]

    Prompt-enabled large ai models for csi feedback[M/OL]

    GUO J, CUI Y , WEN C, et al. Prompt-enabled large ai models for csi feedback[M/OL]. arXiv,

  8. [1]

    Smart radio environments empowered by reconfigurable AI meta-surfaces: An idea whose time has come[J]

    DI RENZO M, DEBBAH M, PHAN-HUY D T, et al. Smart radio environments empowered by reconfigurable AI meta-surfaces: An idea whose time has come[J]. Eurasip Journal on Wireless Communicatoins and Networks, 2019

Show all 44 references
  1. [2]

    Channel cus- tomization for joint Tx-RISs-Rx design in hy- brid mmWave systems[J]

    CHEN W, WEN C K, LI X, et al. Channel cus- tomization for joint Tx-RISs-Rx design in hy- brid mmWave systems[J]. IEEE Transactions on Wireless Communications, 2023, 22(11): 8304- 8319

  2. [3]

    Joint transceiver beamforming and reflecting design for active RIS-aided ISAC systems[J]

    ZHU Q, LI M, LIU R, et al. Joint transceiver beamforming and reflecting design for active RIS-aided ISAC systems[J]. IEEE Transactions on Vehicular Technology, 2023, 72(7): 9636- 9640

  3. [4]

    Rate- splitting multiple access for UA V-based RIS- enabled interference-limited vehicular communi- cation system[J]

    BANSAL A, AGRAW AL N, SINGH K. Rate- splitting multiple access for UA V-based RIS- enabled interference-limited vehicular communi- cation system[J]. IEEE Transactions on Intelli- gent Vehicles, 2023, 8(1): 936-948

  4. [5]

    Exploiting multi- layer refracting RIS-assisted receiver for HAP- SWIPT networks[J]

    AN K, SUN Y , LIN Z, et al. Exploiting multi- layer refracting RIS-assisted receiver for HAP- SWIPT networks[J]. IEEE Transactions on Wireless Communications, 2024, 23(10): 12638- 12657

  5. [6]

    Joint user as- sociation, resource allocation, and beamform- ing in RIS-assisted multi-server MEC systems [J]

    HE W, HE D, MA X, et al. Joint user as- sociation, resource allocation, and beamform- ing in RIS-assisted multi-server MEC systems [J]. IEEE Transactions on Wireless Communi- cations, 2024, 23(4): 2917-2932

  6. [7]

    Multi-functional RIS-assisted semantic anti-jamming communi- cation and computing in integrated aerial-ground networks[J]

    SUN Y , LIN Z, AN K, et al. Multi-functional RIS-assisted semantic anti-jamming communi- cation and computing in integrated aerial-ground networks[J]. IEEE Journal on Selected Areas in Communications, 2024, 42(12): 3597-3617

  7. [8]

    Active-passive cascaded RIS-aided receiver design for jamming nulling and signal enhancing[J]

    SUN Y , ZHU Y , AN K, et al. Active-passive cascaded RIS-aided receiver design for jamming nulling and signal enhancing[J]. IEEE Transac- tions on Wireless Communications, 2024, 23(6): 5345-5362

  8. [9]

    Integrated com- munications and security: RIS-assisted simulta- neous transmission and generation of secret keys [J]

    GAO N, Y AO Y , JIN S, et al. Integrated com- munications and security: RIS-assisted simulta- neous transmission and generation of secret keys [J]. IEEE Transactions on Information Forensics and Security, 2024, 19: 7573-7587

  9. [10]

    Coverage en- hancement by deploying RIS in 5G commercial mobile networks: Field trials[J]

    SANG J, YUAN Y , TANG W, et al. Coverage en- hancement by deploying RIS in 5G commercial mobile networks: Field trials[J]. IEEE Wireless Communications, 2024, 31(1): 172-180

  10. [11]

    Simulation and field trial results of reconfigurable intelligent sur- faces in 5G networks[J]

    LIU R, DOU J, LI P, et al. Simulation and field trial results of reconfigurable intelligent sur- faces in 5G networks[J]. IEEE Access, 2022, 10: 122786-122795

  11. [12]

    Real world field trial for RIS-aided commer- cial 5G mmWave wireless communication[C]// 2024 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit)

    SHOKAIR A, TOUBAL A, GRAO G, et al. Real world field trial for RIS-aided commer- cial 5G mmWave wireless communication[C]// 2024 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit). 2024: 576-581

  12. [13]

    Intelligent sur- faces empowered wireless network: Recent ad- vances and the road to 6G[J]

    WU Q, ZHENG B, YOU C, et al. Intelligent sur- faces empowered wireless network: Recent ad- vances and the road to 6G[J]. Proceedings of the IEEE, 2024

  13. [15]

    Channel estimation with reconfigurable intelli- gent surfaces–A general framework[J]

    SWINDLEHURST A L, ZHOU G, LIU R, et al. Channel estimation with reconfigurable intelli- gent surfaces–A general framework[J]. Proceed- ings of the IEEE, 2022, 110(9): 1312-1338

  14. [16]

    MIMO broadcast channels with finite-rate feedback[J]

    JINDAL N. MIMO broadcast channels with finite-rate feedback[J]. IEEE Transactions on In- formation Theory, 2006, 52(11): 5045-5060

  15. [17]

    An overview of limited feedback in wire- less communication systems[J]

    LOVE D J, HEATH R W, Jr., LAU V K N, et al. An overview of limited feedback in wire- less communication systems[J]. IEEE Journal on 12 China Communications Selected Areas in Communications, 2008, 26(8): 1341-1365

  16. [18]

    Codebook-based so- lutions for reconfigurable intelligent surfaces and their open challenges[J]

    AN J, XU C, WU Q, et al. Codebook-based so- lutions for reconfigurable intelligent surfaces and their open challenges[J]. IEEE Wireless Commu- nications, 2024, 31(2): 134-141

  17. [19]

    Reconfigurable intelligent surfaces for 6G systems: Principles, applications, and research directions[J]

    PAN C, REN H, W ANG K, et al. Reconfigurable intelligent surfaces for 6G systems: Principles, applications, and research directions[J]. IEEE Communications Magazine, 2021, 59(6): 14-20

  18. [20]

    AI- assisted MAC for reconfigurable intelligent- surface-aided wireless networks: Challenges and opportunities[J]

    CAO X, Y ANG B, HUANG C, et al. AI- assisted MAC for reconfigurable intelligent- surface-aided wireless networks: Challenges and opportunities[J]. IEEE Communications Maga- zine, 2021, 59(6): 21-27

  19. [21]

    Dimension reduced chan- nel feedback for reconfigurable intelligent sur- face aided wireless communications[J]

    SHEN D, DAI L. Dimension reduced chan- nel feedback for reconfigurable intelligent sur- face aided wireless communications[J]. IEEE Transactions on Communications, 2021, 69(11): 7748-7760

  20. [22]

    Triple-structured sparsity-based channel feedback for RIS-assisted MU-MIMO system[J]

    SHI X, W ANG J, SONG J. Triple-structured sparsity-based channel feedback for RIS-assisted MU-MIMO system[J]. IEEE Communications Letters, 2022, 26(5): 1141-1145

  21. [23]

    Lim- ited channel feedback scheme for reconfigurable intelligent surface assisted MU-MIMO wireless communication systems[J]

    SHIN B S, OH J H, YOU Y H, et al. Lim- ited channel feedback scheme for reconfigurable intelligent surface assisted MU-MIMO wireless communication systems[J]. IEEE Access, 2022, 10: 50288-50297

  22. [24]

    Deep learning-based CSI feedback for RIS-aided massive MIMO sys- tems with time correlation[J]

    PENG Z, LI Z, LIU R, et al. Deep learning-based CSI feedback for RIS-aided massive MIMO sys- tems with time correlation[J]. IEEE Wireless Communications Letters, 2024, 13(8): 2060- 2064

  23. [25]

    Quan-transformer based channel feedback for RIS-aided wireless communication systems[J]

    XIE W, ZOU J, XIAO J, et al. Quan-transformer based channel feedback for RIS-aided wireless communication systems[J]. IEEE Communica- tions Letters, 2022, 26(11): 2631-2635

  24. [28]

    Deep learning- based joint channel estimation and CSI feedback for RIS-assisted communications[J]

    HAO FENG Y Z, Yuting Xu. Deep learning- based joint channel estimation and CSI feedback for RIS-assisted communications[J]. IEEE Com- munications Letters, 2024, 28(8): 1860-1864

  25. [29]

    Convolutional autoencoder-based phase shift feedback com- pression for intelligent reflecting surface-assisted wireless systems[J]

    YU X, LI D, XU Y , et al. Convolutional autoencoder-based phase shift feedback com- pression for intelligent reflecting surface-assisted wireless systems[J]. IEEE Communications Let- ters, 2022, 26(1): 89-93

  26. [30]

    RISMC- Net: A two-timescale CSI feedback solution for RIS-aided multi-carrier systems[C]//2023 6th In- ternational Conference on Electronics Technol- ogy (ICET)

    TANG X, XIAO L, ZHAO M, et al. RISMC- Net: A two-timescale CSI feedback solution for RIS-aided multi-carrier systems[C]//2023 6th In- ternational Conference on Electronics Technol- ogy (ICET). IEEE, 2023: 598-602

  27. [31]

    Im- pact of finite-resolution precoding and limited feedback on rates of IRS based mmWave net- works[J]

    CHENG M, W ANG J B, ZHANG H, et al. Im- pact of finite-resolution precoding and limited feedback on rates of IRS based mmWave net- works[J]. IEEE Transactions on Vehicular Tech- nology, 2022, 71(5): 5172-5186

  28. [32]

    Rate loss analysis of reconfigurable intelligent surface- aided NOMA with limited feedback[J]

    ALMASI M A, JAFARKHANI H. Rate loss analysis of reconfigurable intelligent surface- aided NOMA with limited feedback[J]. IEEE Open Journal of the Communications Society, 2024, 5: 856-871

  29. [35]

    Learning-based adaptive IRS control with limited feedback codebooks[J]

    KIM J, HOSSEINALIPOUR S, MARCUM A C, et al. Learning-based adaptive IRS control with limited feedback codebooks[J]. IEEE Trans- actions on Wireless Communications, 2022, 21 (11): 9566-9581

  30. [36]

    Limited feedback diver- sity techniques for correlated channels[J]

    LOVE D, HEATH R. Limited feedback diver- sity techniques for correlated channels[J]. IEEE Transactions on Vehicular Technology, 2006, 55 (2): 718-722

  31. [37]

    Ensem- ble properties of RVQ-based limited-feedback beamforming codebooks[J]

    RAGHA V AN V , VEERA V ALLI V V . Ensem- ble properties of RVQ-based limited-feedback beamforming codebooks[J]. IEEE Transactions on Information Theory, 2013, 59(12): 8224- 8249

  32. [38]

    Angle- dependent phase shifter model for reconfigurable China Communications 13 intelligent surfaces: Does the angle-reciprocity hold?[J]

    CHEN W, BAI L, TANG W, et al. Angle- dependent phase shifter model for reconfigurable China Communications 13 intelligent surfaces: Does the angle-reciprocity hold?[J]. IEEE Communications Letters, 2020, 24(9): 2060-2064

  33. [40]

    New SI: Study on artificial in- telligence (AI)/machine learning (ML) for NR air interface[M/OL]

    3GPP-RP-213599. New SI: Study on artificial in- telligence (AI)/machine learning (ML) for NR air interface[M/OL]. Moderator (Qualcomm), Tech. Rep., 2022. https://www.3gpp.org/ftp/tsg ran/ TSG RAN/TSGR 94e/Docs/RP-213599.zip

  34. [41]

    Phase shift compression for con- trol signaling reduction in irs-aided wireless sys- tems: Global attention and lightweight design [J]

    YU X, LI D. Phase shift compression for con- trol signaling reduction in irs-aided wireless sys- tems: Global attention and lightweight design [J]. IEEE Transactions on Wireless Communi- cations, 2024

  35. [42]

    Enabling large intelligent surfaces with compres- sive sensing and deep learning[J]

    TAHA A, ALRABEIAH M, ALKHATEEB A. Enabling large intelligent surfaces with compres- sive sensing and deep learning[J]. IEEE Access, 2021, 9: 44304-44321

  36. [2025]

    14 China Communications

    https://arxiv.org/abs/2501.10629. 14 China Communications

Pith tools

Reviewed August 6, 2026 · model on record in the stance chip above.