Pinching-Antenna Systems (PASS)-based Indoor Positioning

Anna Li; Arumugam Nallanathan; Jun Wang; Tianwei Hou; Xin Sun; Yaoyu Zhang; Yuanwei Liu

REVIEW 3 major objections 3 minor 5 cited by

Pinching-Antenna Systems (PASS)-based Indoor Positioning

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

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Pith's one-line read Pinching antennas achieve meter-level indoor positioning

desk verdict A plausible engineering proposal that applies pinching antennas to RSSI-based indoor positioning; the abstract alone doesn't validate the load-bearing RSSI-to-distance mapping, but the idea is coherent enough to warrant full peer review. read the letter →

arxiv 2508.08185 v1 pith:WRCA5BTT submitted 2025-08-11 eess.SY cs.SY

Yaoyu Zhang , Xin Sun , Jun Wang , Tianwei Hou , Anna Li , Yuanwei Liu , Arumugam Nallanathan This is my paper · ORCID

classification eess.SYcs.SY

keywords pinchingantennaindoorpositioningRSSIweightedleastsquareswaveguideline-of-sightchanneluplinklocalizationreceivedsignalstrength

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 a pinching-antenna system (PASS)—a waveguide with embedded dielectric particles that reconstructs line-of-sight channels—can be used for uplink indoor positioning. It proposes measuring the distance from a user to each pinching antenna via received signal strength (RSSI), then solving for the user's two-dimensional coordinates with a weighted least squares algorithm. The paper's central claims are that positioning accuracy and robustness improve as more pinching antennas are added to the waveguide, that gains become marginal beyond a threshold, and that users located between or near pinching antennas are located most accurately. If these claims hold, PASS hardware would offer a tunable indoor positioning capability whose accuracy is set by antenna count and depends on geometry.

What carries the argument

The load-bearing mechanism is the pinching-antenna system (PASS): a flexible waveguide with embedded dielectric particles that intelligently reconstructs line-of-sight channels. In this paper it carries the argument in three linked pieces: the geometric deterministic model relating user position to received signal at each antenna, the RSSI-based distance estimator built on that model, and the weighted least squares solver that converts the distance estimates into user coordinates. The waveguide's ability to produce a deterministic, meter-level-reconstructed channel model is what makes signal strength usable for distance.

What would settle it

Run a controlled indoor experiment in a reflective room: place a transmitter at known positions and measure the RSSI reported at each pinching antenna. If received signal strength is not monotonically related to distance—or if two different positions yield the same readings—the meter-level positioning claim fails in that setting.

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Extended reading notes

Core claim

The core discovery is a new application of pinching-antenna systems: instead of only shaping line-of-sight communication channels, the same hardware can locate users by converting the deterministic geometric model of each antenna's received signal into distance estimates, and combining those estimates through weighted least squares. The paper asserts that this RSSI-based uplink pipeline achieves meter-level positioning, with accuracy and robustness increasing in the number of pinching antennas per waveguide until a saturation threshold is reached. It also asserts that user positions lying between or near pinching antennas are measured most accurately. These results are presented as simulatio

Load-bearing premise

The fragile premise is that measured signal strength at each pinching antenna maps reliably and monotonically to user distance in real indoor conditions, a mapping that multipath, shadowing, and unknown transmit power can easily break.

Editorial extensions

If this is right

Indoor positioning accuracy can be tuned at design time by choosing the number of pinching antennas per waveguide: more antennas improve accuracy and robustness up to a saturation threshold.
Beyond that threshold, adding antennas yields only marginal gains, so system designers can trade cost against precision.
Users positioned between or near pinching antennas are expected to get the best position estimates, making accuracy geometry-dependent.
The same PASS infrastructure used for line-of-sight channel reconstruction could double as an indoor positioning system without separate hardware.

Reading between the lines

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

A natural extension the paper leaves implicit is testing whether the RSSI-to-distance mapping survives real indoor multipath; standard indoor radio experience suggests the mapping is sensitive to reflections, shadowing, and unknown transmit power.
A testable extension would be to compare PASS positioning error against the number of antennas in a physical prototype to find the saturation threshold empirically, rather than only in simulation.
If the deterministic channel model transfers to practice, PASS positioning could be combined with ranging from other modalities, such as timing or angle, to fix the weak spots of signal-strength-only location.

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Editorial analysis

A structured set of objections, weighed in public.

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

Desk Editor's Note

read the letter

Quick take: a plausible engineering proposal that puts a known 6G antenna concept to use for indoor positioning. The novelty is the application to PASS, not the localization pipeline: RSSI ranging plus weighted least squares is textbook, and the three reported observations (more anchors help, saturation, geometry dependence) are what you'd expect. That's not a knock; the authors are clear that the system model for PASS uplink positioning is the new part.

What's good: the paper sees an opportunity and is honest about the scope. The PASS geometric deterministic model might actually give a more controlled RSSI-to-distance relationship than ordinary antennas, because the waveguide geometry and particle placement create a known field pattern. If the full text backs that up with equations and simulations, this is a useful contribution to the integrated sensing literature.

The soft spot is exactly where the stress test points: the abstract gives no quantitative validation, no noise model, no experimental data. The central claim of meter-level accuracy rests entirely on an RSSI-to-distance mapping being reliable and invertible in a real indoor environment. That's a well-known hard problem; multipath, shadowing, transmit power uncertainty, and calibration error all break the monotonicity. If the simulation uses a clean LOS channel with known parameters, the accuracy results are self-consistent but don't transfer. That's a load-bearing concern, not a minor omission.

I want to be fair: this is an abstract-only review. The full text may well include a proper multipath model, a noise analysis, or even measurements. The idea is coherent, the authors are clearly thinking about the real channel, and the PASS geometry at least gives them a plausible path to a better RSSI model. So I'd send this to peer review. A serious referee should focus on whether the RSSI-to-distance inversion is justified in realistic conditions and whether the WLS error analysis handles bias. Desk rejection would be premature.

For me: I wouldn't cite it on the strength of the abstract, but I'd read the full version if it appears.

Referee Report

3 major / 3 minor

Summary. The paper proposes a pinching-antenna system (PASS) for uplink indoor positioning. It first introduces a system model for PASS-based uplink positioning, then develops an RSSI-based distance estimator from each pinching antenna, and finally applies weighted least squares (WLS) to compute user 2D coordinates. The abstract claims three results: (i) more pinching antennas per waveguide improve accuracy and robustness, (ii) performance gains saturate beyond a threshold number of antennas, and (iii) user positions near or between pinching antennas are localized most accurately.

Significance. If the claims hold, this would be a novel application of PASS hardware to indoor positioning, with accuracy tunable by antenna count and a geometry-dependent error profile. The proposed pipeline is plausible: RSSI-to-distance plus WLS is a standard localization architecture, and PASS geometry is deterministic. However, the abstract provides no quantitative validation, no comparison baseline, and no noise model, so the significance is conditional on the full paper supplying the missing evidence. The paper does not appear to claim any circular derivation; the main risk is external validity of the RSSI-to-distance mapping in realistic indoor channels.

major comments (3)

[Abstract] The load-bearing claim is that RSSI measured at each pinching antenna maps reliably and invertibly to user-to-antenna distance. The abstract refers only to a 'geometric deterministic model and meter-level reconstruction' without specifying whether measurements are simulated or experimental, what channel impairments (multipath, shadowing, unknown transmit power) are included, or how the RSSI-to-distance mapping is calibrated. In real indoor environments RSSI is often non-monotonic in distance, so the paper must state the channel model and calibration procedure explicitly, and ideally include a sensitivity analysis to shadowing and noise. Without this, the meter-level positioning claim is unsupported.
[Abstract/Results] The abstract lists qualitative observations (accuracy improves with more PAs, saturates after a threshold, better near/between PAs) but gives no quantitative results: no RMSE values, no antenna-count threshold, no comparison against baselines such as TOA/TDOA or classical RSSI localization. Because the central contribution is an accuracy claim, the manuscript should report numeric positioning error, robustness metrics, and the actual saturation threshold in the results section and, at least in summary form, in the abstract.
[WLS weighting (abstract)] The PASS-based WLS algorithm is mentioned but the weighting rule is not described. If the weights derive from the same deterministic model used to generate the simulated measurements, the accuracy results may be self-consistent rather than indicative of real-world performance. The paper should specify the measurement noise model, the variance used for weighting, and whether the same model is used in both data generation and estimation. Ideally, a Monte Carlo analysis with mismatched model parameters would demonstrate robustness.

minor comments (3)

[Abstract] Language: 'firstly proposed' is awkward; consider 'we propose the first uplink positioning system model for PASS.' Also 'PASS-based RSSI method is proposed' could be simplified.
[Abstract] The phrase 'Pinching antenna (PA), a flexible waveguide integrated with dielectric particles' is grammatically incomplete; consider 'A pinching antenna (PA) is a flexible waveguide integrated with dielectric particles that...'.
[General] The abstract should define 'PASS' consistently and avoid re-introducing it as both the antenna and the system; this will help readers unfamiliar with the pinching-antenna literature.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity found in abstract-level review

full rationale

The available manuscript (abstract only) describes a proposed PASS-based uplink positioning system: a geometric deterministic channel model, an RSSI-based distance estimation method, and a weighted least squares positioning solver. No load-bearing step in this description reduces by construction to its own inputs. There are no equations, no fitted parameters, no self-citations, and no imported uniqueness theorems visible in the abstract. The RSSI-to-distance mapping is asserted as a method, not derived from the positioning result. Consequently, no specific circular step can be quoted or exhibited. The concern that the model may be self-consistent rather than externally validated is a correctness risk, not a circularity, because circularity requires a demonstrable definitional identity or fitted-input-renamed-as-prediction within the paper's own argument. With no such evidence in the available text, the honest finding is no significant circularity.

Assumptions & free parameters 2 free parameters · 3 assumptions · 0 invented entities

Because this is an abstract-only review, the ledger is necessarily incomplete: the full text is required to enumerate all fitted parameters, e.g., path-loss exponents, noise floors, PA spacing, and the WLS weight rules. The entries above are the minimal set implied by the abstract. No new physical entities are introduced in the abstract; PASS and PA refer to the prior-art pinching-antenna hardware concept. The novelty is in its use for positioning, not in a new mechanism.

free parameters (2)

RSSI-to-distance mapping parameters (path-loss exponent, transmit power, noise variance)
Abstract-only: the RSSI method converts received power to distance, which in practice requires assuming or calibrating a path-loss model and transmit power. These likely appear in the full text as assumed constants or as values fitted to the simulated channel.
WLS weighting rule / measurement noise variance
Weighted least squares requires a weight per distance estimate; if the noise variance is chosen to match the simulated channel, it is a tuning choice whose value shapes the reported accuracy. The abstract does not specify it.

assumptions (3)

domain assumption The pinching-antenna waveguide admits a geometric deterministic channel model whose parameters are known a priori
Abstract states PASS has a 'geometric deterministic model and meter-level reconstruction'; the positioning accuracy claims depend on this model being accurate in real indoor environments, including multipath conditions.
domain assumption Received signal strength varies monotonically and predictably with user-to-antenna distance under the model
The proposed RSSI method 'measures the distance from the users to each PA', which requires an invertible RSSI-distance relationship; indoor shadowing and fading generally break this.
standard math Standard weighted least squares localization yields a unique, stable solution geometry for the PASS layout
The WLS algorithm relies on standard statistical estimation theory; not stated in the abstract but implicit in 'calculating the two-dimensional coordinates'.

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Cite this review

Pith. "Pith review of Pinching-Antenna Systems (PASS)-based Indoor Positioning." pith.science (2026). https://pith.science/paper/WRCA5BTT

@misc{pith2026250808185,
  author       = {Pith},
  title        = {Pith review of: Pinching-Antenna Systems (PASS)-based Indoor Positioning},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/WRCA5BTT}},
  note         = {Machine review of arXiv:2508.08185}
}

read the original abstract

Pinching antenna (PA), a flexible waveguide integrated with dielectric particles, intelligently reconstructs line-of-sight channels. Utilizing its geometric deterministic model and meter-level reconstruction, PA systems (PASS) are applied to uplink indoor positioning. In this paper, the uplink positioning system model for PASS is firstly proposed. A PASS-based received signal strength indication (RSSI) method is proposed to measure the distance from the users to each PA, which is efficient and suitable for PASS. PASS-based weighted least squares (WLS) algorithm is designed to calculate the two-dimensional coordinates of the users. Several critical observations can be drawn from our results: i) More PAs on the waveguide improves the positioning accuracy and robustness. ii) When the number of PAs exceeds a certain threshold, the performance gain becomes marginal. iii) User locations between and near PAs yield superior positioning accuracy.

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Forward citations

Cited by 5 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

On the Performance of Pinching-Antenna Systems (PASS) Under Dynamic Channels with Blockages
eess.SP 2026-07 conditional novelty 6.0 of 10

Under a geometry-aware blockage model, pinching-antenna outage and rate are derived, showing NLoS scattering hurts outage but helps rate and can sustain service when LoS is blocked.
Pinching-Antenna Systems (PASS)-Based User-Side Navigation: An Anchor-Line-based Approach
eess.SP 2026-07 conditional novelty 6.0 of 10

Users can self-locate to centimeter accuracy from downlink timing and power measurements in a pinching-antenna corridor, jointly estimating unknown antenna positions via Lambert W and weighted least squares.
Phase-Aware Localization in Pinching Antenna Systems: CRLB Analysis and ML Estimation
cs.IT 2026-02 conditional novelty 6.0 of 10

Phase-aware localization in pinching antenna systems achieves sub-meter accuracy in simulation, with a closed-form Cramér-Rao bound showing phase information scales as distance^-4 versus amplitude's distance^-6.
On the Blockage Effect in Pinching-Antenna Systems (PASS)
eess.SP 2026-07 conditional novelty 5.0 of 10

Obstacles modeled as random cylinders in a Poisson field give closed-form outage and rate formulas for pinching-antenna systems, with the sliding antenna beating a fixed center antenna.
Uplink Positioning for PASS in Multipath Environments
eess.SP 2026-07 conditional novelty 4.0 of 10

A multipath-robust uplink positioning framework for pinching-antenna systems, with a matrix-pencil ranging algorithm and a low-complexity rank-one variant, plus closed-form variance and position-error-bound analysis.

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