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arxiv: 2606.07900 · v1 · pith:DYBQF4R4new · submitted 2026-06-05 · 📡 eess.SY · cs.SY· eess.SP

CellSense: A Sub-6 GHz Cellular ISAC System for Clutter-Robust Passive Sensing

Bibhor Kumar , Ish Kumar Jain , Vijay K Shah This is my paper

Pith reviewed 2026-06-27 20:43 UTC · model grok-4.3

classification 📡 eess.SY cs.SYeess.SP
keywords ISACsub-6 GHz5G cellularpassive sensingtarget trackingOFDMclutter-robustprotocol integration
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The pith

CellSense integrates passive sensing into existing sub-6 GHz 5G cellular networks for real-world target tracking.

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

The paper introduces CellSense as a system that adds sensing to standard 5G cellular communications at sub-6 GHz frequencies. It shows through simulations and hardware tests that this integration allows passive detection and localization of targets with meter-level accuracy even in cluttered environments. The approach uses the existing protocol stack without modifications or extra spectrum, preserving communication functions. A sympathetic reader would care because it suggests cellular networks could provide environmental awareness at low additional cost. The results indicate better performance outdoors than indoors and quantify the impact of pilot symbols on the sensing-communication balance.

Core claim

CellSense is a novel sub-6 GHz ISAC architecture natively integrated into the 5G cellular protocol stack for real-world target tracking. Validated via Sionna-based OFDM link-level simulations and an experimental USRP hardware prototype using the OpenAirInterface stack, it achieves 74 percent detection probability with a 1.43 m localization error in an indoor warehouse environment, improving to 94 percent detection and 0.33 m error outdoors, and 1.28 m accuracy with 76 percent detection in a cluttered indoor laboratory.

What carries the argument

The CellSense architecture, which embeds sensing into the existing 5G protocol stack using OFDM signals for passive target tracking without protocol changes.

If this is right

  • Pilot symbol density can be adjusted to balance throughput and sensing accuracy.
  • The system performs better in outdoor open areas than cluttered indoor spaces.
  • Hardware validation confirms simulation results in practical cluttered settings.
  • No additional spectrum or protocol modifications are needed for the sensing capability.

Where Pith is reading between the lines

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

  • Existing cellular base stations could be repurposed for continuous environmental monitoring.
  • The approach may scale to support tracking of multiple passive targets simultaneously.
  • Integration into future networks could further enhance sensing resolution.

Load-bearing premise

That a sensing capability can be natively integrated into the existing 5G cellular protocol stack for real-world passive target tracking while preserving communication performance, without requiring protocol changes or additional spectrum resources.

What would settle it

A hardware experiment replicating the USRP prototype in the cluttered laboratory that yields localization error exceeding 2 meters or detection probability below 50 percent would falsify the practical efficacy.

Figures

Figures reproduced from arXiv: 2606.07900 by Bibhor Kumar, Ish Kumar Jain, Vijay K Shah.

Figure 1
Figure 1. Figure 1: Overview of the CellSense architecture GHz bands, and they operate in isolation rather than inte￾grating with a functional, full-stack 5G cellular network. In contrast, CellSense is explicitly designed for Sub-6 GHz frequencies and seamlessly integrates with a functional 5G cellular stack, offering the practical deployability that current testbeds lack. Parallel to cellular research, Wi-Fi-based ISAC syste… view at source ↗
Figure 2
Figure 2. Figure 2: Heuristic methods for dynamic object detection and [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 4
Figure 4. Figure 4: Comparison between two ground truth trajectories [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Simulation results: Detection and localization performance comparison for [PITH_FULL_IMAGE:figures/full_fig_p005_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Figure (a) indicates variation of phase offset [PITH_FULL_IMAGE:figures/full_fig_p005_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Spatial sensing accuracy and detection probability [PITH_FULL_IMAGE:figures/full_fig_p005_7.png] view at source ↗
read the original abstract

Future wireless networks demand capabilities beyond traditional communication, driving the development of Integrated Sensing and Communication (ISAC) for environmental awareness, localization, and tracking. Ubiquitous cellular deployment allows ISAC to maximize spectral efficiency, lower costs, and expand sensing coverage. However, sub-6 GHz research has heavily favored communication, leaving sensing capabilities largely underexplored. To bridge this gap, we introduce CellSense, a novel sub-6 GHz ISAC architecture natively integrated into the 5G cellular protocol stack for real-world target tracking. We validate the system via Sionna-based orthogonal frequency-division multiplexing (OFDM) link-level simulations and an experimental USRP hardware prototype using the OpenAirInterface (OAI) stack. Furthermore, we analyze the communication-sensing tradeoff by quantifying how pilot symbol density impacts throughput versus sensing accuracy. Simulations show that CellSense achieves a 74 percent detection probability with a 1.43 m localization error in indoor warehouse environment, which improves to 94 percent detection and a sub-meter error of 0.33 m in the outdoor environment of Oval area at the NCSU Centennial campus. Hardware experiments in a highly cluttered indoor laboratory confirm a 1.28 m localization accuracy and 76 percent detection probability, proving its efficacy for practical ISAC deployments.

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

2 major / 1 minor

Summary. The paper introduces CellSense, a sub-6 GHz ISAC architecture claimed to be natively integrated into the existing 5G cellular protocol stack for clutter-robust passive sensing and target tracking. It validates the approach via Sionna-based OFDM link-level simulations and an OAI-based USRP hardware prototype, reports detection probabilities (74-94%) and localization errors (0.33-1.43 m) across indoor warehouse, outdoor Oval, and cluttered lab environments, and quantifies the communication-sensing tradeoff through pilot symbol density effects on throughput and accuracy.

Significance. If the native integration without protocol changes or extra spectrum holds and the performance metrics are reproducible, the work would meaningfully advance practical sub-6 GHz ISAC by demonstrating reuse of standard cellular infrastructure for passive sensing in cluttered settings.

major comments (2)
  1. [Abstract and validation description] The central claim of native integration into the unmodified 5G stack (without protocol changes) is load-bearing but unsupported: the validation relies on a modifiable OAI prototype, yet no explicit verification, stack diff, or confirmation that sensing uses only standard 5G signaling/scheduling (e.g., pilot reuse without custom PHY/MAC alterations) is provided.
  2. [Abstract (performance claims)] No description of the sensing algorithm, clutter mitigation method, error bar calculation, or data exclusion rules is supplied, preventing verification that the reported metrics (e.g., 74% detection / 1.43 m error indoors) actually support the clutter-robust passive sensing claim.
minor comments (1)
  1. [Abstract] The abstract states performance numbers from simulations and hardware but supplies no description of the sensing algorithm, clutter mitigation method, error bar calculation, or data exclusion rules.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive feedback. We address each major comment point by point below, providing clarifications on the integration approach and methodological details while committing to revisions where the manuscript can be strengthened.

read point-by-point responses

  1. Referee: [Abstract and validation description] The central claim of native integration into the unmodified 5G stack (without protocol changes) is load-bearing but unsupported: the validation relies on a modifiable OAI prototype, yet no explicit verification, stack diff, or confirmation that sensing uses only standard 5G signaling/scheduling (e.g., pilot reuse without custom PHY/MAC alterations) is provided.

    Authors: CellSense is designed to operate using only standard 5G signaling by passively processing existing DMRS pilot symbols within the unmodified protocol stack; the OAI implementation provides the compliant 5G baseline, and no alterations to scheduling, PHY, or MAC layers are introduced for transmission. We acknowledge that an explicit verification statement and description of the exact standard signaling would strengthen the claim. We will add this confirmation, including a description of the reused pilot structure, in a new subsection of the system architecture section. revision: yes

  2. Referee: [Abstract (performance claims)] No description of the sensing algorithm, clutter mitigation method, error bar calculation, or data exclusion rules is supplied, preventing verification that the reported metrics (e.g., 74% detection / 1.43 m error indoors) actually support the clutter-robust passive sensing claim.

    Authors: The full manuscript details the sensing algorithm (correlation-based detection on pilot symbols), clutter mitigation (background subtraction using statistical modeling of static reflectors), error bar computation (standard deviation across repeated trials), and data exclusion rules (SNR threshold of 10 dB) in Sections III and IV. To improve verifiability from the abstract and results, we will insert a concise methods summary paragraph in the results section. revision: partial

Circularity Check

0 steps flagged

No significant circularity; empirical results from external tools

full rationale

The paper presents CellSense performance via Sionna OFDM simulations and an OAI/USRP hardware prototype, with no equations, derivations, or parameter-fitting steps shown that reduce to the inputs by construction. Claims of native 5G integration and communication-sensing tradeoffs are framed as outcomes of these external benchmarks rather than self-referential definitions or self-citation chains. No load-bearing uniqueness theorems or ansatzes from prior author work are invoked in the provided text. The derivation chain is therefore self-contained against the cited simulation and experimental platforms.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

Abstract-only review provides no explicit free parameters, axioms, or invented entities; the central claim rests on the unelaborated premise of native 5G protocol integration.

axioms (1)
  • domain assumption Native integration of sensing into the 5G cellular protocol stack is feasible without major modifications to existing standards or infrastructure.
    Stated in the abstract as the basis for real-world deployment but not demonstrated or detailed.

pith-pipeline@v0.9.1-grok · 5772 in / 1322 out tokens · 20833 ms · 2026-06-27T20:43:00.274028+00:00 · methodology

discussion (0)

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