Pith. sign in

REVIEW 3 major objections 4 minor 61 references

New Mid-Band (FR3, 6-24 GHz) XL-MIMO for 6G: Channel Modeling, Algorithm Evaluation, and Field Trials

T0 review · 3 major / 4 minor · reviewed 2026-08-05 · deepseek-v4-flash

Pith's one-line read Field trials in the U6GHz band show that target signal-to-noise ratio, not raw antenna count, determines how much XL-MIMO downlink capacity is unlocked, while uplink remains constrained.

desk verdict A broad, self-referential survey wrapped around a single-stream U6GHz field-trial curve; the spatial-multiplexing conclusion outruns the evidence. read the letter →

arxiv 2608.03783 v1 pith:J3I3TRW7 submitted 2026-08-04 eess.SP

classification eess.SP
keywords FR3newmid-band(6-24GHz)XL-MIMOnear-fieldpropagationspatialnon-stationaritychannelmodelingU6GHzfieldtrialsignal-to-noiseratio
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

The paper is a system-level review and measurement study arguing that the new mid-band (FR3, 6–24 GHz) is a strong candidate spectrum for 6G, and that XL-MIMO with hundreds to thousands of antennas is the key technology to exploit it. Its central experimental claim comes from U6GHz (6425–7125 MHz) field trials: downlink throughput grows with target SNR, jumping from about 0.5 Gbps around the 64QAM threshold to nearly 1.5 Gbps in 256QAM, while uplink peaks near 0.44 Gbps. A companion model-based analysis shows why antenna-count scaling eventually saturates: under near-field non-uniform spherical wave propagation, SNR converges to a constant bound as the number of antennas grows, unlike the unbounded linear prediction of conventional far-field plane-wave models. The paper also reviews spectrum allocation, channel measurement, four XL-MIMO architectures (co-located, cell-free, sparse/movable, intelligent), near-field channel modeling, and estimation and beamforming algorithms. A careful reader would care because these results calibrate expectations: array size alone is not enough; the link budget and target SNR are what convert large arrays into throughput.

What carries the argument

The load-bearing objects are (i) the near-field non-uniform spherical wave (NUSW) model, which treats each array element as seeing its own geometric distance and projected aperture to the source, and (ii) the virtual XL-MIMO array, built by sliding a 32×2 dual-polarized array through four horizontal and three vertical translations to emulate a 128×6 (1536-element) aperture for channel sounding. The NUSW model is what produces the SNR-saturation result; the virtual array is what turns a modest physical sounder into a large-aperture measurement without building a full 1536-element array. The field-trial counterpart is a 1024-element, 128-channel U6GHz prototype with 400 MHz bandwidth whose mea

What would settle it

Take a true 1536-element array and a sliding virtual array through the same UMa route and compare angular spread, capacity, and near-field phase correlation; if the two diverge beyond measurement uncertainty, the stationarity assumption behind the virtual array fails. Separately, plot measured or simulated SNR versus antenna count at a fixed FR3 frequency: continued 3 dB gain per doubling at large counts would falsify the NUSW saturation claim, while an observed plateau would confirm it.

Watch

Extended reading notes

Core claim

The paper's central discovery, stated on its own terms, is that the practical payoff of an extremely large array in the new mid-band is gated by the link SNR. In outdoor UMa field trials at 6425–6825 MHz with a 1024-element, 400 MHz prototype, downlink single-stream rate climbs monotonically with target SNR and enters higher-order modulation regions as SNR rises, while uplink throughput grows far more slowly. Complementing this, a model-based analysis of 768- and 1536-element modular arrays shows that under near-field non-uniform spherical-wave propagation the achievable SNR converges to a constant as antenna count grows, in contrast to the unbounded linear gain predicted by the far-field un

Load-bearing premise

The load-bearing premise is that the virtual 1536-element array, assembled by sliding a 32×2 physical array across twelve translations, experiences an unchanged propagation channel during the whole measurement; any environmental change across translations distorts the measured angular spreads, capacities, and near-field phase checks.

Editorial extensions

If this is right

  • At a given site, engineering the link SNR (through coverage, power, beamforming gain, and modulation threshold) is the first-order lever; adding antennas beyond the point where SNR saturates yields little single-user rate under near-field propagation.
  • Near-field effects should be treated as a first-class constraint in XL-MIMO: algorithms and models that assume planar wavefronts will systematically overestimate SNR for very large arrays.
  • The U6GHz band can support multi-Gbps downlink in real outdoor deployments when high SNR is available, so system design should focus on extending high-SNR regions rather than only increasing array size.
  • Uplink requires a different solution set—UE transmit power, channel estimation accuracy, power control, or distributed/cell-free reception—since the trial shows it lags far behind downlink.
  • Measured angular spreads and channel-hardening trends provide calibration data for updating standardized channel models for the FR3 band.

Reading between the lines

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

  • Editorial inference: the SNR-saturation curve implies an optimal array size below the physical maximum; beyond that point, marginal elements mainly add multi-user spatial separation rather than coherent single-user gain. The paper does not pursue this design trade-off.
  • Editorial inference: the virtual-array method is credible only if the propagation environment is frozen during the mechanical translations; if stationarity is violated, angular spreads could be inflated or subarray phase relationships distorted. A direct check would be comparing virtual-array results with a true 1536-element array along the same UMa route.
  • Editorial inference: the downlink/uplink asymmetry suggests the FR3 band may favor deployments with asymmetric link budgets, such as fixed wireless access or downlink-heavy traffic, unless uplink enhancement techniques mature.
  • Editorial inference: the same NUSW-based SNR saturation should appear at other frequencies within 6–24 GHz; whether the saturation point shifts with frequency is a clean next measurement to test the model's generality.
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

3 major / 4 minor

Summary. The paper is a hybrid survey-and-experimental contribution on FR3 (6-24 GHz) XL-MIMO for 6G. It reviews spectrum allocation and standardization activities, describes a wideband TDM-MIMO channel sounder and a virtual 128x6 (1536-element) array formed by mechanically sliding a 32x2 array, summarizes measured channel characteristics (angular spreads, channel hardening, capacity, near-field phase, spatial non-stationarity), reviews channel estimation and beamforming algorithms, presents model-based SNR comparisons between far-field UPW and near-field NUSW models for 768 and 1536 antennas, and reports U6GHz field trials with a 1024-element prototype. The headline conclusion is that the target SNR is a critical factor for XL-MIMO performance: sufficiently high SNR substantially improves peak downlink capacity and spatial multiplexing gain, whereas uplink performance remains constrained.

Significance. If fully supported, the field-trial result would be a valuable datapoint for U6GHz XL-MIMO deployment, and the channel sounder covering 3-16 GHz with up to 1536 virtual elements is a useful experimental platform. The model-based UPW-versus-NUSW comparison also highlights an important qualitative point about near-field array gain saturation. However, the central field-trial claim currently overreaches: Fig. 20 is explicitly a single-stream rate-versus-SNR curve, and the demonstrated monotonic throughput growth across QPSK/16QAM/64QAM/256QAM is standard adaptive modulation behavior, not evidence of spatial multiplexing gain. The review portions are broad and cite a substantial body of work, though they lean heavily on the authors' own prior publications. Overall, the paper is a useful survey with an intriguing but not yet established experimental conclusion.

major comments (3)
  1. [Section VI.C, Fig. 20; abstract; Section VII.A] The claim that sufficiently high SNR 'substantially improves peak downlink capacity and enhances the spatial multiplexing gain' is not supported by the evidence presented. Fig. 20 is explicitly labeled 'single-stream rate and SNR'; the throughput increase with SNR through the QPSK, 16QAM, 64QAM, and 256QAM regions is standard adaptive modulation and coding for a single link and does not depend on XL-MIMO. No rank indicator, number of streams, or multi-stream throughput is reported, so the 'spatial multiplexing gain' part of the conclusion is not measured. In addition, 'target SNR' appears to be the achieved/observed SNR; without controlled variation at fixed array and channel conditions, the correlation may be confounded by distance, shadowing, or channel realization. The model-based NUSW analysis in Section V.D is a separate analytical/simulated comparison and does not provide field-tri
  2. [Section III, Fig. 4] The virtual 128x6 (1536-element) array is formed by mechanically sliding a 32x2 physical array through four horizontal and three vertical translations. The validity of the measurement-based results in Section IV (angular spreads, inverse condition number, channel capacity, near-field phase verification) hinges on the assumption that the propagation channel is stationary over the entire mechanical translation interval. The manuscript does not report any stationarity validation, such as repeated reference-path measurements during the sliding procedure, nor does it quantify the translation time or environment stability. If the environment changes during the multiple translations, the measured angular spreads, capacities, and near-field phase checks will be distorted. Please add a stationarity check or explicitly state and justify the stationarity assumption and its possible effect on the re
  3. [Section V.D, Figs. 13-15] The model-based SNR comparison is not reproducible as written. No closed-form expressions for the UPW and NUSW SNR are given, and the absolute path gain at a reference distance, transmit power, noise figure, bandwidth, and array normalization are not specified. Consequently, the key qualitative claim that the NUSW SNR converges to a constant bound while the UPW SNR grows unboundedly cannot be checked from the manuscript, and the reported 3.01 dB spacing between 1536 and 768 elements in Fig. 14 is asserted rather than derived from the stated model. In addition, the text after Fig. 13 says at 'the 100 MHz frequency point' the far-field UPW model breaks down because the array aperture expands to 'hundreds of meters'; with half-wavelength spacing and the described 16-column modular array, this aperture estimate is not consistent with the stated geometry, and the plotted frequency range in th
minor comments (4)
  1. [Section IV.A.5, Eq. (3)] There is a sign inconsistency: Eq. (3) correctly writes S(k) = -1 when p_n_k - p_n_{k-1} <= -3 dB, but the surrounding text says 'when p_n_k - p_n_{k-1} <= 3 dB' without the minus sign. Please correct the text.
  2. [Section IV.A.5, Eq. (5)] The weights w_c, w_a, w_d and the threshold rho in Eq. (5) are not specified or referenced. Since the stationary-interval partitioning result depends on these choices, please provide default values or cite the estimation procedure.
  3. [Section VI.C, Fig. 20] The figure would be substantially more informative with error bars or confidence intervals, the number of repeated trials, and a definition of how 'target SNR' is set or measured. The caption currently states only that modulation switching regions are indicated.
  4. [Throughout] There are numerous typographical and style errors (e.g., 'Besides, The research' in Section I.3, 'U A V' in Section I.3, 'the 6G open innovation test device' repeated, and several missing articles). A full language edit is recommended before resubmission.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: model evaluation is a review of external NUSW results, and the field trial is an independent measurement; the multiplexing-gain overreach is a correctness issue, not a circular derivation.

full rationale

The paper's model-based SNR evaluation (Section V.D, Figs. 13–15) reproduces the NUSW-vs-UPW saturation result by citing [48], [50], [53], which are prior external works; no curve is fitted to the same data and no fitted parameter is renamed as a prediction. The central field-trial claim (Section VI.C, Fig. 20) is an empirical measurement of single-stream throughput vs SNR in the U6GHz band; this is independent evidence that SNR strongly affects throughput, and the conclusion is not equivalent by construction to any input. Self-citations ([12], [24], [25], [30]) support the review's channel-characterization and model content, but they are peer-reviewed publications with stated assumptions and are not used to manufacture the field-trial result. The abstract/conclusion's extension to 'spatial multiplexing gain' is not supported because Fig. 20 shows only a single-stream rate; however, that is an overgeneralization/missing evidence, not circularity. The unvalidated stationarity assumption for the virtual array (Section III) is a methodological weakness, not a circular step. No part of the paper derives a quantity from a definition of that same quantity, fits a parameter and then predicts it, or imports a uniqueness theorem from the authors' prior work.

Assumptions & free parameters 3 free parameters · 3 assumptions · 0 invented entities

The central claims rest on a standard 3GPP-style channel model, the authors' own channel sounder and virtual array methodology, and a model-based SNR evaluation whose inputs are not fully specified. No new physical entities are introduced.

free parameters (3)
  • weights w_c, w_a, w_d and threshold rho in stationary interval partitioning
    Equation (5) uses hand-chosen weights and threshold to decide sub-interval boundaries; no fitting procedure or sensitivity analysis is given, and the resulting boundaries in Fig. 9 depend on these values.
  • 3 dB birth/death threshold for MPCs = 3 dB
    Equation (3) sets a 3 dB power difference as the criterion for MPC birth/death; this is chosen without justification and affects the candidate boundary set S(k).
  • User geometry for SNR evaluation = r=20 m, theta=60 deg, phi=45 deg
    The SNR curves in Section V.D are computed for a single chosen user location; the reported 3.01 dB spacing and saturation behavior may shift for other geometries.
assumptions (3)
  • domain assumption The 3GPP TR 38.901 framework extended with spherical-wave and spatial non-stationarity is the correct channel model for FR3 XL-MIMO
    Invoked in Section IV.A.6 and equations (7)-(11) via [13] and [30]; the applicability of the model to 6-24 GHz is taken from the authors' prior work rather than independently validated in this paper.
  • domain assumption The virtual sliding-platform array is equivalent to a true 1536-element XL-MIMO array
    Section III describes emulating a 1536-element array by moving a 32x2 array on a mechanical platform, which assumes the channel remains unchanged during the translations; no stationarity validation is reported.
  • ad hoc to paper The NUSW near-field model and its array-gain behavior apply to the simulated FR3 scenarios
    Section V.D computes SNR with the NUSW model from [53] to generate Figs. 13-15; the parameterization is inherited from the authors' prior publications, making the saturation conclusion a property of the model rather than an independent measurement.

how reviews work

0 comments
Cite this review

Pith. "Pith review of New Mid-Band (FR3, 6-24 GHz) XL-MIMO for 6G: Channel Modeling, Algorithm Evaluation, and Field Trials." pith.science (2026). https://pith.science/paper/J3I3TRW7

@misc{pith2026260803783,
  author       = {Pith},
  title        = {Pith review of: New Mid-Band (FR3, 6-24 GHz) XL-MIMO for 6G: Channel Modeling, Algorithm Evaluation, and Field Trials},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/J3I3TRW7}},
  note         = {Machine review of arXiv:2608.03783}
}
read the original abstract

The new mid-band (FR3, 6-24 GHz) spectrum is expected to play an important role in future 6G networks by providing a favorable balance among coverage, capacity, and deployment feasibility. Meanwhile, extremely large-scale multiple-input multiple-output (XL-MIMO) has emerged as a key enabling technology to exploit the propagation and spatial multiplexing potential of these frequency bands. Firstly, this paper provides a systematic review of spectrum allocation and standardization activities for new mid-band spectrum, together with the 6G spectrum planning strategies of countries and regions. Secondly, the wideband massive MIMO channel sounder is also introduced, which is specially developed for channel measurements of new mid-band with over a thousand elements. Thirdly, propagation characteristics and channel modeling approaches of four representative XL-MIMO architectures, including co-located, cell-free, and intelligent XL-MIMO, are comprehensively reviewed and analyzed, with particular emphasis on near-field propagation, spatial non-stationarity, and capacity performance. Then, recent advances in channel estimation, beamforming, and artificial-intelligence-assisted signal processing are summarized. In addition, the performance of new mid-band XL-MIMO systems equipped with 1536 and 768 antenna elements is comparatively evaluated. Finally, real communication environment prototype system field trials conducted in the Upper 6 GHz (U6GHz) band are used to investigate practical system performance under realistic deployment conditions. The results indicate that the target signal-to-noise ratio is a critical factor affecting XL-MIMO performance in the U6GHz band.

Figures

Figures reproduced from arXiv: 2608.03783 by the authors.

Figure 1
Figure 1. XL-MIMO characteristics and deployment in the new mid-band (FR3) band. [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. The operating and potential spectrum in ITU regions. [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 4
Figure 4. XL-MIMO channel measurement environment and [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗
Figures from the paper (15 more)
Figure 3
Figure 3. Figure 3: Massive MIMO channel sounder. (a) TDM-MIMO [PITH_FULL_IMAGE:figures/full_fig_p006_3.png]
Figure 5
Figure 5. Figure 5: Inverse condition number vs number of Tx antennas [PITH_FULL_IMAGE:figures/full_fig_p007_5.png]
Figure 6
Figure 6. Figure 6: The channel capacity in the 6 GHz band. (a) 16 Rx [PITH_FULL_IMAGE:figures/full_fig_p007_6.png]
Figure 8
Figure 8. Figure 8: The phase verification in the new mid-band. (a) Near [PITH_FULL_IMAGE:figures/full_fig_p008_8.png]
Figure 9
Figure 9. Figure 9: Degree of independence of sub-intervals obtained by [PITH_FULL_IMAGE:figures/full_fig_p009_9.png]
Figure 11
Figure 11. Figure 11: The channel capacity of CF-mMIMO and Conven [PITH_FULL_IMAGE:figures/full_fig_p012_11.png]
Figure 12
Figure 12. Figure 12: The antenna spacing of MIMO array elements. [PITH_FULL_IMAGE:figures/full_fig_p013_12.png]
Figure 13
Figure 13. Figure 13: Comparison of SNR with 768 array elements from [PITH_FULL_IMAGE:figures/full_fig_p016_13.png]
Figure 14
Figure 14. Figure 14: Comparison of SNR with 384, 768, and 1536 array [PITH_FULL_IMAGE:figures/full_fig_p017_14.png]
Figure 15
Figure 15. Figure 15: Comparison of SNR under different frequency bands [PITH_FULL_IMAGE:figures/full_fig_p017_15.png]
Figure 17
Figure 17. Figure 17: U6GHz band XL-MIMO array antenna base station. [PITH_FULL_IMAGE:figures/full_fig_p018_17.png]
Figure 16
Figure 16. Figure 16: The 6G open innovation test device from prototype [PITH_FULL_IMAGE:figures/full_fig_p018_16.png]
Figure 18
Figure 18. Figure 18: Overall architecture of 6G prototype system platform. [PITH_FULL_IMAGE:figures/full_fig_p019_18.png]
Figure 19
Figure 19. Figure 19: U6GHz XL-MIMO test site environment. (a) Tx end [PITH_FULL_IMAGE:figures/full_fig_p019_19.png]
Figure 20
Figure 20. Figure 20: The single-stream rate and SNR of XL-MIMO in the [PITH_FULL_IMAGE:figures/full_fig_p019_20.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

61 extracted references · 53 canonical work pages

  1. [1]

    Framework and overall objectives of the future development of imt for 2030 and beyond,

    I. Recommendation, “Framework and overall objectives of the future development of imt for 2030 and beyond,”International Telecommuni- cation Union (ITU) Recommendation (ITU-R), 2023

  2. [2]

    Technology trends for massive MIMO towards 6G,

    Y . Huo, X. Lin, B. Di, H. Zhang, F. J. L. Hernando, A. S. Tan, S. Mumtaz, ¨O. T. Demir, and K. Chen-Hu, “Technology trends for massive MIMO towards 6G,”Sensors, vol. 23, no. 13, p. 6062, 2023

  3. [3]

    Xl-mimo channel measurement, characterization, and modeling for 6g: A survey,

    P. Tang, J. Zhang, H. Miao, Q. Wei, W. Zuo, L. Tian, T. Jiang, and G. Liu, “Xl-mimo channel measurement, characterization, and modeling for 6g: A survey,”Frontiers of Information Technology & Electronic Engineering, vol. 25, no. 12, pp. 1627–1650, 2024

  4. [4]

    Performance analysis and low-complexity design for XL-MIMO with near-field spatial non-stationarities,

    K. Zhi, C. Pan, H. Ren, K. K. Chai, C.-X. Wang, R. Schober, and X. You, “Performance analysis and low-complexity design for XL-MIMO with near-field spatial non-stationarities,”IEEE Journal on Selected Areas in Communications, vol. 42, no. 6, pp. 1656–1672, 2024

  5. [5]

    Channel measurement, modeling, and simulation for 6G: A survey and tutorial,

    J. Zhang, J. Lin, P. Tang, Y . Zhang, H. Xu, T. Gao, H. Miao, Z. Chai, Z. Zhou, Y . Liet al., “Channel measurement, modeling, and simulation for 6G: A survey and tutorial,”arXiv preprint arXiv:2305.16616, 2023

  6. [6]

    A tutorial on extremely large-scale mimo for 6g: Fundamentals, signal processing, and applications,

    Z. Wang, J. Zhang, H. Du, D. Niyato, S. Cui, B. Ai, M. Debbah, K. B. Letaief, and H. V . Poor, “A tutorial on extremely large-scale mimo for 6g: Fundamentals, signal processing, and applications,”IEEE Communications Surveys & Tutorials, vol. 26, no. 3, pp. 1560–1605, 2024

  7. [7]

    A. F. Molisch,Wireless communications. John Wiley & Sons, 2012

  8. [8]

    Measurement-based massive MIMO channel modeling in 13–17 GHz for indoor hall scenarios,

    J. Chen, X. Yin, and S. Wang, “Measurement-based massive MIMO channel modeling in 13–17 GHz for indoor hall scenarios,” in2016 IEEE International Conference on Communications (ICC). IEEE, 2016, pp. 1–5. JOURNAL OF LATEX CLASS FILES, VOL. 14, NO. 8, AUGUST 2021 21

Show all 61 references
  1. [9]

    Channel capacities of non-stationary 6G massive MIMO channels with mutual coupling veri- fied by channel measurements,

    Y . Yang, Y . Zheng, C.-X. Wang, and J. Huang, “Channel capacities of non-stationary 6G massive MIMO channels with mutual coupling veri- fied by channel measurements,” in2022 IEEE 33rd Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). ...

  2. [10]

    Measurement-Based channel modeling for spatial non- stationarity with multipath components,

    G. Jing, J. Hong, X. Yin, J. Rodr ´ıguez-Pi˜neiro, Y . Tong, Y . Yu, and Z. Yu, “Measurement-Based channel modeling for spatial non- stationarity with multipath components,”IEEE Transactions on Wireless Communications, vol. 25, pp. 4530–4546, 2026

  3. [11]

    Spatial non- stationary near-field channel modeling and validation for massive MIMO systems,

    Z. Yuan, J. Zhang, Y . Ji, G. F. Pedersen, and W. Fan, “Spatial non- stationary near-field channel modeling and validation for massive MIMO systems,”IEEE Transactions on Antennas and Propagation, vol. 71, no. 1, pp. 921–933, 2022

  4. [12]

    Far-field to near-field: Experimental studies of MIMO channel charac- terization and modeling in the 6 GHz band,

    H. Miao, J. Zhang, P. Tang, L. Tian, W. Zuo, H. Xing, and G. Liu, “Far-field to near-field: Experimental studies of MIMO channel charac- terization and modeling in the 6 GHz band,”IEEE Journal on Selected Areas in Communications, 2025

  5. [13]

    Study on channel model for frequencies from 0.5 to 100 GHz(Release 15),

    3GPP, “Study on channel model for frequencies from 0.5 to 100 GHz(Release 15),” 3GPP, Tech. Rep. TR 38.901, Dec. 2017

  6. [14]

    Ultra-massive MIMO channel measure- ments at 5.3 GHz and a general 6G channel model,

    Y . Zheng, C.-X. Wang, R. Yang, L. Yu, F. Lai, J. Huang, R. Feng, C. Wang, C. Li, and Z. Zhong, “Ultra-massive MIMO channel measure- ments at 5.3 GHz and a general 6G channel model,”IEEE Transactions on Vehicular Technology, vol. 72, no. 1, pp. 20–34, 2022

  7. [15]

    Far- and near-field channel measurements and characterization in the Terahertz band using a virtual antenna array,

    Y . Wang, S. Sun, and C. Han, “Far- and near-field channel measurements and characterization in the Terahertz band using a virtual antenna array,” IEEE Communications Letters, vol. 28, no. 5, pp. 1186–1190, 2024

  8. [16]

    Chan- nel hardening in massive MIMO: Model parameters and experimental assessment,

    S. Willhammar, J. Flordelis, L. Van Der Perre, and F. Tufvesson, “Chan- nel hardening in massive MIMO: Model parameters and experimental assessment,”IEEE Open Journal of the Communications Society, vol. 1, pp. 501–512, 2020

  9. [17]

    6G ISAC enables environment object reconstruction,

    B. Zhou, J. Zang, C. Wu, Y . Liu, Q. Liu, J. He, J. Qiu, G. Wang, X. Bi, M. Maet al., “6G ISAC enables environment object reconstruction,” IEEE Journal of Selected Topics in Electromagnetics, Antennas and Propagation, 2025

  10. [18]

    Channel estimation for UPA- Assisted near-field channel in extremely large-scale massive MIMO systems,

    X. Peng, L. Zhao, Y . Jiang, and J. Liu, “Channel estimation for UPA- Assisted near-field channel in extremely large-scale massive MIMO systems,” in2024 IEEE International Conference on Communications Workshops (ICC Workshops), 2024, pp. 738–743

  11. [19]

    GAN-Based near-field channel estimation for extremely large-scale MIMO systems,

    M. Ye, X. Liang, C. Pan, Y . Xu, M. Jiang, and C. Li, “GAN-Based near-field channel estimation for extremely large-scale MIMO systems,” IEEE Transactions on Green Communications and Networking, vol. 9, no. 1, pp. 304–316, 2025

  12. [20]

    Low com- plexity orthogonal matching pursuit-based near-field channel estimation in XL-MIMO systems,

    C. Ruan, Z. Zhang, H. Jiang, Y . Qi, J. Dang, and L. Wu, “Low com- plexity orthogonal matching pursuit-based near-field channel estimation in XL-MIMO systems,”IEEE Communications Letters, vol. 28, no. 12, pp. 2859–2863, 2024

  13. [21]

    Low-complexity zero-forcing precoding for XL-MIMO transmissions,

    L. N. Ribeiro, S. Schwarz, and M. Haardt, “Low-complexity zero-forcing precoding for XL-MIMO transmissions,” in2021 29th European Signal Processing Conference (EUSIPCO), 2021, pp. 1621–1625

  14. [22]

    Resource allocation for near-field communications: Fundamentals, tools, and outlooks,

    B. Xu, J. Zhang, H. Du, Z. Wang, Y . Liu, D. Niyato, B. Ai, and K. B. Letaief, “Resource allocation for near-field communications: Fundamentals, tools, and outlooks,”IEEE Wireless Communications, vol. 31, no. 5, pp. 42–50, 2024

  15. [23]

    Jac-PCG based low- complexity precoding for extremely large-scale MIMO systems,

    B. Xu, J. Zhang, J. Li, H. Xiao, and B. Ai, “Jac-PCG based low- complexity precoding for extremely large-scale MIMO systems,”IEEE Transactions on Vehicular Technology, vol. 72, no. 12, pp. 16 811– 16 816, 2023

  16. [24]

    New mid-band for 6g: several considerations from the channel propagation characteristics perspective,

    J. Zhang, H. Miao, P. Tang, L. Tian, and G. Liu, “New mid-band for 6g: several considerations from the channel propagation characteristics perspective,”IEEE Communications Magazine, vol. 63, no. 1, pp. 175– 180, 2025

  17. [25]

    Measurement-based massive MIMO channel characterization in 6 GHz band for 6G,

    H. Miao, P. Tang, J. Zhang, L. Tian, H. Xu, S. Liu, T. Gao, and Y . Li, “Measurement-based massive MIMO channel characterization in 6 GHz band for 6G,” in2024 IEEE Wireless Communications and Networking Conference (WCNC), 2024, pp. 1–6

  18. [26]

    Channel hardening in 6G FR3 XL-MIMO: measurement-based analysis and modeling in a UMa scenario,

    P. Tang, Q. Wei, J. Zhang, H. Miao, Q. Zhen, W. Zuo, E. Liu, and L. Tian, “Channel hardening in 6G FR3 XL-MIMO: measurement-based analysis and modeling in a UMa scenario,”IEEE Antennas and Wireless Propagation Letters, pp. 1–5, 2025

  19. [27]

    Measurement-based analysis of XL-MIMO channel characteristics in a corridor scenario,

    Q. Wei, P. Tang, H. Miao, W. Zuo, L. Tian, J. Zhang, G. Liu, and M. Jian, “Measurement-based analysis of XL-MIMO channel characteristics in a corridor scenario,” in2024 IEEE 99th Vehicular Technology Conference (VTC2024-Spring), 2024, pp. 1–6

  20. [28]

    Analysis of near-field effects, spatial non-stationary characteristics based on 11- 15 GHz channel measurement in indoor scenario,

    H. Miao, P. Tang, W. Zuo, Q. Wei, L. Tian, and J. Zhang, “Analysis of near-field effects, spatial non-stationary characteristics based on 11- 15 GHz channel measurement in indoor scenario,” in2024 IEEE 25th International Workshop on Signal Processing Advances in Wireless Commu...

  21. [29]

    Analysis of spatial non-stationary characteristics for 6G XL-MIMO communication,

    W. Zuo, P. Tang, H. Miao, Q. Wei, L. Tian, J. Zhang, G. Liu, and M. Jian, “Analysis of spatial non-stationary characteristics for 6G XL-MIMO communication,”2024 IEEE 99th Vehicular Technology Conference (VTC2024-Spring), pp. 1–6, 2024

  22. [30]

    Near-field propagation and spatial non-stationarity channel model for 6–24 ghz (fr3) extremely large-scale mimo: Adopted by 3gpp for 6g,

    H. Xu, J. Zhang, P. Tang, H. Xing, H. Miao, N. Zhang, J. Li, J. Wu, W. Yang, Z. Zhang, W. Jiang, Z. He, A. Haghighat, Q. Wang, and G. Liu, “Near-field propagation and spatial non-stationarity channel model for 6–24 ghz (fr3) extremely large-scale mimo: Adopted by 3gpp for 6g,”...

  23. [31]

    Cell-Free massive MIMO versus small cells,

    H. Q. Ngo, A. Ashikhmin, H. Yanget al., “Cell-Free massive MIMO versus small cells,”IEEE Transactions on Wireless Communications, vol. 16, no. 3, pp. 1834–1850, 2017

  24. [32]

    Ubiquitous cell- free massive MIMO communications,

    G. Interdonato, E. Bj ¨ornson, H. Quoc Ngoet al., “Ubiquitous cell- free massive MIMO communications,”EURASIP Journal on Wireless Communications and Networking, vol. 2019, no. 1, pp. 1–13, 2019

  25. [33]

    Paulraj, R

    A. Paulraj, R. Nabar, and D. Gore,Introduction to space-time wireless communications. Cambridge university press, 2003

  26. [34]

    Goldsmith,Wireless communications

    A. Goldsmith,Wireless communications. Cambridge university press, 2005

  27. [35]

    Capacity of multi-antenna Gaussian channels,

    E. Telatar, “Capacity of multi-antenna Gaussian channels,”European transactions on telecommunications, vol. 10, no. 6, pp. 585–595, 1999

  28. [36]

    Cell-free versus conventional massive mimo : An analysis of channel capacity based on channel measurement in the fr3 band,

    Q. Zhen, P. Tang, H. Miao, E. Liu, X. Liu, Z. Ding, and J. Zhang, “Cell-free versus conventional massive mimo : An analysis of channel capacity based on channel measurement in the fr3 band,” inICC 2026 - IEEE International Conference on Communications, 2026, pp. 1–6

  29. [37]

    Simulating motion - incorporating spatial consistency into NYUSIM channel model,

    S. Ju and T. S. Rappaport, “Simulating motion - incorporating spatial consistency into NYUSIM channel model,” in2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), 2018, pp. 1–6

  30. [38]

    A measurement-based spatially consistent channel model for distributed MIMO in industrial environments,

    C. Nelson, S. Willhammar, and F. Tufvesson, “A measurement-based spatially consistent channel model for distributed MIMO in industrial environments,” 2025. [Online]. Available: https://arxiv.org/abs/2412. 12646

  31. [39]

    The COST 2100 MIMO channel model,

    L. Liu, C. Oestges, J. Poutanen, K. Haneda, P. Vainikainen, F. Quitin, F. Tufvesson, and P. De Doncker, “The COST 2100 MIMO channel model,”IEEE Wireless Communications, vol. 19, no. 6, pp. 92–99, 2012

  32. [40]

    Modeling and performance analysis for movable antenna enabled wireless communications,

    L. Zhu, W. Ma, and R. Zhang, “Modeling and performance analysis for movable antenna enabled wireless communications,”IEEE Transactions on Wireless Communications, vol. 23, no. 6, pp. 6234–6250, 2024

  33. [41]

    6D movable antenna based on user distribution: Modeling and optimization,

    X. Shao, Q. Jiang, and R. Zhang, “6D movable antenna based on user distribution: Modeling and optimization,”IEEE Transactions on Wireless Communications, 2024

  34. [42]

    Channel estimation for extremely large-scale massive MIMO: Far-field, near-field, or hybrid-field?

    X. Wei and L. Dai, “Channel estimation for extremely large-scale massive MIMO: Far-field, near-field, or hybrid-field?”IEEE Commu- nications Letters, vol. 26, no. 1, pp. 177–181, 2022

  35. [43]

    Enhanced polar-domain channel estimation for near-field XL-MIMO in low-SNR scenarios,

    H. Wang, T. Yan, N. Zhou, X. Li, F. Wen, and W. Du, “Enhanced polar-domain channel estimation for near-field XL-MIMO in low-SNR scenarios,”IEEE Transactions on Vehicular Technology, vol. 74, no. 12, pp. 19 407–19 419, 2025

  36. [44]

    Parametric channel estimation for LoS dominated holographic massive MIMO systems,

    M. Ghermezcheshmeh and N. Zlatanov, “Parametric channel estimation for LoS dominated holographic massive MIMO systems,”IEEE Access, vol. 11, pp. 44 711–44 724, 2023

  37. [45]

    Channel estimation for extremely large-scale massive MIMO systems,

    Y . Han, S. Jin, C.-K. Wen, and X. Ma, “Channel estimation for extremely large-scale massive MIMO systems,”IEEE Wireless Communications Letters, vol. 9, no. 5, pp. 633–637, 2020

  38. [46]

    Tensor-based channel estimation for near-field millimeter wave XL-MIMO systems,

    S. Cheng, L. You, Z. Jin, L. Cheng, and X. Gao, “Tensor-based channel estimation for near-field millimeter wave XL-MIMO systems,”IEEE Wireless Communications Letters, vol. 14, no. 7, pp. 1909–1913, 2025

  39. [47]

    Joint dictionary learning and channel estimation in hybrid-field XL-MIMO systems,

    M. Jiang, Y . Shi, Z. Hu, and Y . Li, “Joint dictionary learning and channel estimation in hybrid-field XL-MIMO systems,”IEEE Internet of Things Journal, vol. 12, no. 24, pp. 55 936–55 940, 2025

  40. [48]

    Near-field modeling and performance analysis of modular extremely large-scale array communi- cations,

    X. Li, H. Lu, Y . Zeng, S. Jin, and R. Zhang, “Near-field modeling and performance analysis of modular extremely large-scale array communi- cations,”IEEE Communications Letters, vol. 26, no. 7, pp. 1529–1533, 2022

  41. [49]

    Clustered double-scattering channel modeling for XL-MIMO with uniform arrays,

    D. W. M. Guerra and T. Abr ˜ao, “Clustered double-scattering channel modeling for XL-MIMO with uniform arrays,”IEEE Access, vol. 10, pp. 20 173–20 186, 2022

  42. [50]

    Modular extremely large-scale array communication: Near-field modelling and performance analysis,

    X. Li, H. Lu, Y . Zeng, S. Jin, and R. Zhang, “Modular extremely large-scale array communication: Near-field modelling and performance analysis,”China Communications, vol. 20, no. 4, pp. 132–152, 2023

  43. [51]

    Near-field modeling and performance analysis for multi-user extremely large-scale MIMO communication,

    H. Lu and Y . Zeng, “Near-field modeling and performance analysis for multi-user extremely large-scale MIMO communication,”IEEE Communications Letters, vol. 26, no. 2, pp. 277–281, 2022. 22

  44. [52]

    Utility-based precoding optimization framework for large intelligent surfaces,

    E. Bj ¨ornson and L. Sanguinetti, “Utility-based precoding optimization framework for large intelligent surfaces,” in2019 53rd Asilomar Con- ference on Signals, Systems, and Computers, 2019, pp. 863–867

  45. [53]

    Communicating with extremely large-scale ar- ray/surface: Unified modeling and performance analysis,

    H. Lu and Y . Zeng, “Communicating with extremely large-scale ar- ray/surface: Unified modeling and performance analysis,”IEEE Trans- actions on Wireless Communications, vol. 21, no. 6, pp. 4039–4053, 2022

  46. [54]

    Chan- nel estimation for XL-MIMO systems with polar-domain multi-scale residual dense network,

    H. Lei, J. Zhang, H. Xiao, X. Zhang, B. Ai, and D. W. K. Ng, “Chan- nel estimation for XL-MIMO systems with polar-domain multi-scale residual dense network,”IEEE Transactions on Vehicular Technology, vol. 73, no. 1, pp. 1479–1484, 2024

  47. [55]

    An adaptive and robust deep learning framework for THz ultra-massive MIMO channel estimation,

    W. Yu, Y . Shen, H. He, X. Yu, S. Song, J. Zhang, and K. B. Letaief, “An adaptive and robust deep learning framework for THz ultra-massive MIMO channel estimation,”IEEE Journal of Selected Topics in Signal Processing, vol. 17, no. 4, pp. 761–776, 2023

  48. [56]

    GNN-enhanced approximate message passing for massive/ultra-massive MIMO detection,

    H. He, A. Kosasih, X. Yu, J. Zhang, S. Song, W. Hardjawana, and K. B. Letaief, “GNN-enhanced approximate message passing for massive/ultra-massive MIMO detection,” in2023 IEEE Wireless Com- munications and Networking Conference (WCNC), 2023, pp. 1–6

  49. [57]

    Double-layer power control for mobile cell-free XL-MIMO with multi-agent reinforcement learning,

    Z. Liu, J. Zhang, Z. Liu, H. Xiao, and B. Ai, “Double-layer power control for mobile cell-free XL-MIMO with multi-agent reinforcement learning,”IEEE Transactions on Wireless Communications, vol. 23, no. 5, pp. 4658–4674, 2024

  50. [58]

    Channel modeling and channel estimation for holographic massive MIMO with planar arrays,

    O. T. Demir, E. Bj ¨ornson, and L. Sanguinetti, “Channel modeling and channel estimation for holographic massive MIMO with planar arrays,” IEEE Wireless Communications Letters, vol. 11, no. 5, pp. 997–1001, 2022

  51. [59]

    Bayesian channel estimation in multi-user massive MIMO with extremely large antenna array,

    Y . Zhu, H. Guo, and V . K. N. Lau, “Bayesian channel estimation in multi-user massive MIMO with extremely large antenna array,”IEEE Transactions on Signal Processing, vol. 69, pp. 5463–5478, 2021

  52. [60]

    Accelerated randomized methods for receiver design in extra-large scale MIMO arrays,

    V . Croisfelt, A. Amiri, T. Abrao, E. de Carvalho, and P. Popovski, “Accelerated randomized methods for receiver design in extra-large scale MIMO arrays,”IEEE Transactions on Vehicular Technology, vol. 70, no. 7, pp. 6788–6799, 2021

  53. [61]

    Extremely large aperture massive MIMO: Low complexity receiver architectures,

    A. Amiri, M. Angjelichinoski, E. de Carvalho, and R. W. Heath, “Extremely large aperture massive MIMO: Low complexity receiver architectures,” in2018 IEEE Globecom Workshops (GC Wkshps), 2018, pp. 1–6

Pith tools

Reviewed August 5, 2026 · model on record in the stance chip above.