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arxiv: 2604.14869 · v1 · submitted 2026-04-16 · 📡 eess.SP

Recognition: unknown

An Open-Source Hardware-Aware Sub-THz Radio-Stripe Simulator

Tijl Schepens , Thomas Feys , Thomas Eriksson , Gilles Callebaut
Authors on Pith no claims yet

Pith reviewed 2026-05-10 10:38 UTC · model grok-4.3

classification 📡 eess.SP
keywords sub-THzradio-stripesimulatorhardware impairmentsCP-OFDMopen-sourcedistributed MIMOfiber front-haul
0
0 comments X

The pith

An open-source simulator traces the full waveform-level signal chain in sub-THz radio-stripe systems from central baseband generation through fiber links to impaired radio units.

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

The paper presents a configuration-driven simulator that models sub-terahertz radio-stripe and distributed MIMO architectures at the waveform level. It chains CP-OFDM baseband signals from the central unit through measurement-parameterized polymer microwave fiber and coupler links into radio units that include adjustable nonlinearity, noise, I/Q imbalance, phase noise, and carrier offset. Wireless channels are incorporated via lightweight per-subcarrier models or site-specific ray-tracing data. The simulator exports intermediate waveforms and metrics such as normalised mean square error, signal-to-noise-and-distortion ratio, and bit error rate. A sympathetic reader would value this because these architectures target extreme spatial reuse and multi-GHz bandwidths whose performance is dominated by cascaded hardware and propagation effects that are difficult to isolate in physical testbeds.

Core claim

The simulator provides an end-to-end model of the signal path in sub-THz radio-stripe systems by generating CP-OFDM baseband signals in the central unit, passing them through parameterized polymer microwave fiber and coupler links, applying configurable impairments at the booster or active radio units, and combining with deterministic, stochastic, or ray-tracing wireless channel models before computing performance metrics such as normalised mean square error, signal-to-noise-and-distortion ratio, and bit error rate.

What carries the argument

The configuration-driven full waveform-level signal chain simulator, which chains baseband generation, fiber propagation, RF impairment models, and propagation channels.

If this is right

  • Reproducible studies of how impairments accumulate across cascaded fiber front-haul and RF stages become feasible without physical hardware.
  • Effects of calibration methods and algorithmic decisions such as radio-unit selection and beam management can be evaluated at the waveform level.
  • Intermediate signals can be inspected to isolate degradation at each stage of the chain.
  • Site-specific propagation data can be integrated to assess performance under realistic deployment conditions.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The tool could shorten design cycles by allowing virtual prototyping of sub-THz systems before fabrication.
  • Researchers might use it to rank which impairments most limit overall throughput in given bandwidth and array-size regimes.
  • The same modeling structure could extend to other carrier frequencies that rely on fiber-RF cascades for distributed arrays.

Load-bearing premise

The measurement-parameterized models for polymer microwave fiber, couplers, and RF impairments accurately represent real hardware behavior across the configurations users will test.

What would settle it

A direct comparison of simulator outputs against measured waveforms and metrics from a physical sub-THz radio-stripe prototype using matching fiber, coupler, and radio-unit parameters would settle whether the models reproduce observed impairment accumulation.

Figures

Figures reproduced from arXiv: 2604.14869 by Gilles Callebaut, Thomas Eriksson, Thomas Feys, Tijl Schepens.

Figure 1
Figure 1. Figure 1: A deployment of distributed low-complexity sub-Thz RUs and sub-10GHz with dual-frequency operation. Block diagram of the [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: PMF amplitude response. 110 120 130 140 150 160 170 −3 −2 −1 Frequency [GHz] Amplitude [dB] With balun Without balun [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Coupler amplitude response. D. Radio Units with boost and active mode As illustrated in [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figure 5
Figure 5. Figure 5: The comparison of the LoS with RT channels prove that [PITH_FULL_IMAGE:figures/full_fig_p005_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Example power-delay profiles for the exponential TDL model [PITH_FULL_IMAGE:figures/full_fig_p006_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: AM/AM plots per stage show how PA saturation and noise [PITH_FULL_IMAGE:figures/full_fig_p007_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: Heatmap showing the NMSE at the CU for each individual [PITH_FULL_IMAGE:figures/full_fig_p007_8.png] view at source ↗
read the original abstract

Sub-Terahertz radio-stripe and distributed MIMO architectures promise extreme spatial reuse and multi-GHz bandwidths, but the cascaded fiber front-haul and RF hardware impairments strongly shape end-to-end performance. This paper presents an open-source, configuration-driven simulator that models the full waveform-level signal chain from CP-OFDM baseband generation in the central unit, through measurement-parameterized polymer microwave fiber and coupler links, to booster/active Radio Units (RUs) with configurable nonlinearity, noise, in-phase and quadrature imbalance, and oscillator phase noise and carrier frequency offset. Wireless propagation is supported via lightweight deterministic and stochastic per-subcarrier channel models as well as site-specific ray-tracing datasets generated with a companion Sionna ray-tracer module. The simulator exports intermediate waveforms and system metrics (e.g., normalised mean square error, signal-to-noise-and-distortion ratio, bit error rate) to enable reproducible studies of impairment accumulation, calibration, and algorithmic choices such as RU selection and beam management.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 1 minor

Summary. The paper presents an open-source, configuration-driven simulator for sub-THz radio-stripe and distributed MIMO architectures. It implements the full waveform-level signal chain from CP-OFDM baseband generation in the central unit, through measurement-parameterized polymer microwave fiber and coupler links, to booster/active Radio Units with configurable nonlinearity, noise, I/Q imbalance, oscillator phase noise, and carrier frequency offset. Wireless channels are modeled via lightweight deterministic/stochastic per-subcarrier models and site-specific ray-tracing datasets, with exports of intermediate waveforms and metrics (NMSE, SNDR, BER) to support reproducible studies of impairment accumulation, calibration, and algorithms such as RU selection and beam management.

Significance. If the implementation faithfully matches the described models, this tool would provide substantial value to the sub-THz communications community by enabling hardware-aware, reproducible simulations of cascaded front-haul and RF impairments without physical testbeds. The open-source release, configuration interface, and waveform/metric export features directly address the need for accessible platforms to study impairment accumulation and system-level algorithmic choices in high-bandwidth distributed MIMO setups.

minor comments (1)
  1. [Abstract] The abstract and introduction would benefit from an explicit statement of the simulator's supported bandwidth range and computational scaling to help readers assess applicability to their target scenarios.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive review and the recommendation to accept the manuscript. The recognition of the simulator's potential value to the sub-THz communications community is appreciated.

Circularity Check

0 steps flagged

No circularity: tool-description paper with no derived predictions

full rationale

The manuscript describes an open-source, configuration-driven simulator implementing a waveform-level chain (CP-OFDM baseband through measurement-parameterized PMF/coupler links to RUs with configurable impairments, plus channel models). No new equations are derived, no parameters are fitted to data and then called predictions, and no uniqueness theorems or ansatzes are smuggled via self-citation. The central claim is the existence and architecture of the tool itself; model equations are presented as configurable blocks whose fidelity is a user-facing caveat, not a load-bearing derivation. The open-source release allows direct verification that the implementation matches the text, rendering the contribution self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is a software tool paper rather than a theoretical derivation, so the central contribution rests on standard signal-processing models and hardware impairment descriptions drawn from prior literature rather than new axioms or fitted parameters introduced here.

pith-pipeline@v0.9.0 · 5474 in / 1102 out tokens · 33067 ms · 2026-05-10T10:38:52.217806+00:00 · methodology

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Reference graph

Works this paper leans on

24 extracted references · 16 canonical work pages

  1. [1]

    High-Level Models for Tandem Opera- tion,

    6GTandem Consortium, “High-Level Models for Tandem Opera- tion,” 6GTandem (SNS JU, Grant Agreement No. 101096302), Tech. Rep. D3.1, Mar. 2024

    2024

  2. [2]

    Detailed Models Including Hardware Specifics and Cross-Layer 6GTandem Operation,

    6GTandem Consortium, “Detailed Models Including Hardware Specifics and Cross-Layer 6GTandem Operation,” 6GTandem (SNS JU, Grant Agreement No. 101096302), Tech. Rep. D3.2, Oct. 2024

    2024

  3. [3]

    Final Algorithms for Efficient Transmis- sion and Support for New Services,

    6GTandem Consortium, “Final Algorithms for Efficient Transmis- sion and Support for New Services,” 6GTandem (SNS JU, Grant Agreement No. 101096302), Tech. Rep. D3.4, Oct. 2024

    2024

  4. [4]

    End-to-End Simulation of 5G mmWave Networks,

    M. Mezzavilla et al., “End-to-End Simulation of 5G mmWave Networks,”IEEE Communications Surveys & Tutorials, vol. 20, no. 3, pp. 2237–2263, 2018.DOI: 10.1109/COMST.2018.2828880

    work page doi:10.1109/comst.2018.2828880 2018

  5. [5]

    A Tutorial on NYUSIM: Sub-Terahertz and Millimeter-Wave Channel Simulator for 5G, 6G, and Beyond,

    H. Poddar, S. Ju, D. Shakya, and T. S. Rappaport, “A Tutorial on NYUSIM: Sub-Terahertz and Millimeter-Wave Channel Simulator for 5G, 6G, and Beyond,”IEEE Communications Surveys & Tutori- als, vol. 26, no. 2, pp. 824–857, 2024.DOI: 10.1109/COMST.2023. 3344671

    work page doi:10.1109/comst.2023 2024

  6. [6]

    Hussain, A

    H. Poddar, A. Chowdary, T. S. Rappaport, and M. Chafii, “Full-Stack End-To-End Sub-THz Simulations at 140 GHz using NYUSIM Channel Model in ns-3,” in2024 IEEE Wireless Commu- nications and Networking Conference (WCNC), 2024, pp. 1–6.DOI: 10.1109/WCNC57260.2024.10570665

    work page doi:10.1109/wcnc57260.2024.10570665 2024

  7. [7]

    HermesPy: An Open- Source Link-Level Evaluator for 6G,

    J. Adler, T. Kronauer, and A. N. Barreto, “HermesPy: An Open- Source Link-Level Evaluator for 6G,”IEEE Access, vol. 10, pp. 120 256–120 273, 2022.DOI: 10.1109/ACCESS.2022.3222063

    work page doi:10.1109/access.2022.3222063 2022

  8. [8]

    Waveform Learning Under Phase Noise Impairment for Sub-THz Communications,

    D. Marasinghe, L. H. Nguyen, J. Mohammadi, Y . Chen, T. Wild, and N. Rajatheva, “Waveform Learning Under Phase Noise Impairment for Sub-THz Communications,”IEEE Transactions on Communica- tions, vol. 73, no. 1, pp. 117–131, 2025.DOI: 10.1109/TCOMM. 2024.3430982

    work page doi:10.1109/tcomm 2025

  9. [9]

    TiEMPO: open-source time-dependent end-to- end model for simulating ground-based submillimeter astronomical observations,

    E. Huijten et al., “TiEMPO: open-source time-dependent end-to- end model for simulating ground-based submillimeter astronomical observations,” inMillimeter, Submillimeter, and Far-Infrared Detec- tors and Instrumentation for Astronomy X, SPIE, vol. 11453, 2020, pp. 562–581

    2020

  10. [10]

    Circularly Polarized Sub- THz Antenna Design for Distributed Deployment,

    Y . Cao, M. Wojnowski, and B. K. Lau, “Circularly Polarized Sub- THz Antenna Design for Distributed Deployment,” in2024 18th European Conference on Antennas and Propagation (EuCAP), 2024, pp. 1–4.DOI: 10.23919/EuCAP60739.2024.10501515

    work page doi:10.23919/eucap60739.2024.10501515 2024

  11. [11]

    Sionna RT: Technical report,

    F. Ait Aoudia, J. Hoydis, M. Nimier-David, B. Nicolet, S. Cammerer, and A. Keller, “Sionna RT: Technical Report,” arXiv:2504.21719, Nov. 2025. [Online]. Available: https : / / arxiv. org/abs/2504.21719

    work page arXiv 2025

  12. [12]

    Hoydis et al.,Sionna, version 1.2.1, 2022

    J. Hoydis et al.,Sionna, version 1.2.1, 2022

    2022

  13. [13]

    Nimr (et

    A. Nimr (et. al.),Hexa-X Deliverable D2.3: Radio models and enabling techniques towards ultra-high data rate links and capacity in 6G, Technical Report, Hexa-X Project, avail- able online: https://hexa-x.eu/wp-content/uploads/2023/04/Hexa-X- D2 3 v1.0.pdf, Apr. 2023

    2023

  14. [14]

    Report on Packaged Samples for Antenna Unit and Central Unit and Plastic Fibre for demonstrator including designs, simulation and characterization,

    6GTandem Consortium, “Report on Packaged Samples for Antenna Unit and Central Unit and Plastic Fibre for demonstrator including designs, simulation and characterization,” 6GTandem (SNS JU, Grant Agreement No. 101096302), Tech. Rep. D4.3, Mar. 2024

    2024

  15. [15]

    Gupta, M

    N. Gupta, M. Sarajlic, and E. G. Larsson,Deep Learning for sub- THz Radio Unit Selection using sub-10 GHz Channel Informa- tion and Inferred Device Beamforming, 2025. arXiv: 2507.09244 [eess.SP]. [Online]. Available: https://arxiv.org/abs/2507.09244

    work page arXiv 2025

  16. [16]

    L. V . der Perre et al.,Distributed Deployment and Dual-Frequency Concepts to Strengthen Sub-THz Wireless Systems, 2025. arXiv: 2509.00492[eess.SP]. [Online]. Available: https://arxiv.org/ abs/2509.00492

    work page arXiv 2025

  17. [17]

    Propagation Distance Estimation for Radio over Fiber with Cascaded Structure,

    D. Kong, D. P. Moya Osorio, and E. G. Larsson, “Propagation Distance Estimation for Radio over Fiber with Cascaded Structure,” in2024 IEEE 25th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), 2024, pp. 691– 695.DOI: 10.1109/SPAWC60668.2024.10694520

    work page doi:10.1109/spawc60668.2024.10694520 2024

  18. [18]

    Radio Over Fiber With Cascaded Structure: Algorithm for Uplink Positioning,

    D. Kong, D. P. M. Osorio, and E. G. Larsson, “Radio Over Fiber With Cascaded Structure: Algorithm for Uplink Positioning,”IEEE Transactions on Wireless Communications, vol. 25, pp. 9000–9014, 2026.DOI: 10.1109/TWC.2025.3641043

    work page doi:10.1109/twc.2025.3641043 2026

  19. [19]

    Moryakova, T

    O. Moryakova, T. Eriksson, and H. Johansson,Modeling, Analysis, and Optimization of Cascaded Power Amplifiers, 2025. arXiv: 2503. 14083[eess.SP]. [Online]. Available: https://arxiv.org/abs/2503. 14083

    2025

  20. [20]

    Rottenberg, T

    F. Rottenberg, T. Feys, and N. Tervo,Optimal Training Design for Over-the-Air Polynomial Power Amplifier Model Estimation, 2024. arXiv: 2404.12830[eess.SP]. [Online]. Available: https://arxiv. org/abs/2404.12830

    work page arXiv 2024

  21. [21]

    In2024 IEEE 74th Electronic Components and Technology Conference (ECTC)

    V . Liakonis, Y . Papananos, M. Wojnowski, and W. Hartner, “High- Performance Polymer Microwave Fiber Coupler in eWLB Package for Sub-THz Communication,” in2024 IEEE 74th Electronic Com- ponents and Technology Conference (ECTC), 2024, pp. 748–753. DOI: 10.1109/ECTC51529.2024.00122

    work page doi:10.1109/ectc51529.2024.00122 2024

  22. [22]

    Efficient Implementation of Polymer Microwave Fiber Links Employing Non-Galvanic Coupling Mechanism,

    V . Liakonis, Y . Papananos, F. Dielacher, M. Wojnowski, and W. Hartner, “Efficient Implementation of Polymer Microwave Fiber Links Employing Non-Galvanic Coupling Mechanism,”Applied Sciences, vol. 15, no. 4, p. 1824, 2025.DOI: 10.3390/app15041824 [Online]. Available: https://doi.org/10.3390/app15041824

    work page doi:10.3390/app15041824 2025

  23. [23]

    In: 2025 IEEE International Symposium on Circuits and Systems (ISCAS)

    Y . Yan, V . Vassilev, F. Str¨ombeck, D. Wu, and H. Zirath, “A 48 Gbps Communication Link Over D-Band Polymer Microwave Fiber,” in2025 IEEE International Symposium on Circuits and Systems (ISCAS), 2025, pp. 1–4.DOI: 10.1109/ISCAS56072.2025.11043384

    work page doi:10.1109/iscas56072.2025.11043384 2025

  24. [24]

    D-Band Cascode Up conversion Mixer Utilizing Double Mixing Technique for En- hanced Linearity and Output Power in 130-nm SiGe Process,

    M. Mollaalipour, M. Bao, Y . Yan, and H. Zirath, “D-Band Cascode Up conversion Mixer Utilizing Double Mixing Technique for En- hanced Linearity and Output Power in 130-nm SiGe Process,”IEEE Transactions on Microwave Theory and Techniques, vol. 73, no. 9, pp. 6425–6434, 2025.DOI: 10.1109/TMTT.2025.3560920

    work page doi:10.1109/tmtt.2025.3560920 2025