{"id":"dc9365fa-b4c6-44a4-a12b-8581537c4b15","arxiv_id":"2606.07900","paper_version":1,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":6.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":0,"one_line_summary":"CellSense integrates ISAC into the 5G protocol stack for sub-6 GHz passive sensing, reporting 74-94% detection probability and 0.33-1.43 m localization error in simulations plus 76% detection and 1.28 m accuracy in cluttered hardware tests.","lead":"CellSense is a new architecture that adds passive sensing and target tracking to existing 5G cellular signals in the sub-6 GHz band without extra hardware. A smart generalist might read it to see how everyday wireless networks could gain environmental awareness and tracking abilities using infrastructure already deployed at scale.","discovery_kind":"new_application","skeptic_critique":{"model":"grok-4.3","headline":"Native integration claim rests on unverified assumption that OAI prototype uses unmodified 5G protocol stack","rationale":"The reader's weakest_assumption directly identifies the same integration-without-changes premise as the load-bearing point. Because the full text is now available, the concern can be tested concretely rather than left unverified; the verdict moves from UNVERDICTED to CONDITIONAL pending confirmation that no stack modifications occurred.","tokens_in":1785,"tokens_out":321,"duration_ms":12465,"concrete_test":"Locate the section describing the OAI implementation and any code or configuration diffs; confirm whether any PHY-layer pilot patterns, scheduling, or MAC procedures were altered from the stock OAI 5G stack. If alterations exist, re-run the hardware experiment with unmodified stock OAI to measure whether the reported 1.28 m accuracy and 76 % detection are still achieved.","verdict_should_be":"CONDITIONAL","load_bearing_attack":"The central claim requires that CellSense achieves passive sensing by natively integrating into the existing 5G stack with no protocol changes or extra spectrum. The validation uses Sionna OFDM simulations plus an OAI-based USRP prototype; OAI is a modifiable open-source implementation, so the paper must show that sensing (e.g., pilot reuse for target tracking) was realized strictly through standard 5G signaling and scheduling without custom PHY/MAC alterations. No such explicit verification or diff of stack changes is referenced in the abstract or strongest claim, leaving the “without requiring protocol changes” condition unsecured.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.3","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.","tokens_in":1901,"tokens_out":413,"duration_ms":18325,"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":[{"comment":"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.","section":"Abstract and validation description"},{"comment":"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.","section":"Abstract (performance claims)"}],"minor_comments":[{"comment":"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.","section":"Abstract"}],"recommendation":"major_revision","confidential_remarks":null},"author_rebuttal":{"model":"grok-4.3","summary":"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.","responses":[{"response":"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_made":"yes","referee_comment":"[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."},{"response":"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_made":"partial","referee_comment":"[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."}],"tokens_in":1399,"tokens_out":427,"duration_ms":21551,"standing_objections":[]},"desk_editor":{"model":"grok-4.3","letter":"The paper's main point is a claim that passive sensing can be added to existing sub-6 GHz 5G networks without protocol changes or extra spectrum, shown through Sionna OFDM simulations and a USRP prototype running the OpenAirInterface stack. It gives concrete numbers: 74% detection with 1.43 m error in an indoor warehouse, 94% detection and 0.33 m error outdoors, and 76% detection with 1.28 m accuracy in a cluttered lab. It also quantifies how pilot density trades off throughput against sensing performance.\n\nWhat is new is the explicit framing as a 5G-native architecture aimed at clutter-robust passive tracking, plus the combination of link-level simulation and real hardware in both indoor and outdoor settings. That moves past purely communication-focused sub-6 GHz work and supplies some practical metrics.\n\nThe soft spots are straightforward. The abstract supplies no description of the sensing algorithm, clutter mitigation steps, or how the reported metrics were computed, so it is impossible to judge whether the numbers actually support the central claim. The native-integration argument is also unsecured: OAI is modifiable, yet the paper does not show that sensing was achieved strictly through standard 5G signaling and scheduling with no PHY/MAC alterations. The stress-test concern holds on the information given.\n\nThis is for people working on ISAC hardware prototypes and 5G sensing extensions. A reader who wants to see reported performance in realistic environments can extract some value, but anyone trying to replicate or extend the work will need the missing implementation details.\n\nIt deserves peer review. The topic is relevant and the hardware effort is real; referees can request the algorithm description and stack verification rather than desk-rejecting on the abstract alone.","headline":"CellSense reports sub-6 GHz ISAC numbers from sim and OAI hardware but the abstract gives no sensing algorithm or proof that the 5G stack stayed unmodified.","tokens_in":2387,"tokens_out":435,"would_cite":false,"duration_ms":18961,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.3","headline":"CellSense integrates passive sensing into existing sub-6 GHz 5G cellular networks for real-world target tracking.","keywords":["ISAC","sub-6 GHz","5G cellular","passive sensing","target tracking","OFDM","clutter-robust","protocol integration"],"falsifier":"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.","tokens_in":2679,"feed_emoji":"📡","tokens_out":621,"duration_ms":20091,"temperature":0.7,"pith_summary":"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.","feed_headline":"CellSense enables passive sensing in sub-6 GHz 5G networks","feed_subtitle":"Simulations and hardware tests achieve 1.28 m accuracy in cluttered environments using standard protocols.","key_machinery":"The CellSense architecture, which embeds sensing into the existing 5G protocol stack using OFDM signals for passive target tracking without protocol changes.","core_discovery":"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.","pith_inferences":["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."],"forward_implications":["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."],"fun_headline_variants":["CellSense tracks targets using sub-6 GHz 5G ISAC","1.28 m accuracy in labs with CellSense 5G sensing","CellSense 5G prototype hits 94 percent outdoor detection","USRP tests confirm CellSense ISAC in cluttered spaces","CellSense integrates into 5G stack for real-world sensing"],"cache_read_input_tokens":2112,"weakest_assumption_plain":"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.","fun_headline_variants_meta":{"raw":{"variants":["CellSense tracks targets using sub-6 GHz 5G ISAC","1.28 m accuracy in labs with CellSense 5G sensing","CellSense 5G prototype hits 94 percent outdoor detection","USRP tests confirm CellSense ISAC in cluttered spaces","CellSense integrates into 5G stack for real-world sensing"]},"model":"grok-4.3","cost_usd":0.006986,"raw_usage":{"total_tokens":3261,"prompt_tokens":718,"num_sources_used":0,"completion_tokens":79,"cost_in_usd_ticks":69862000,"prompt_tokens_details":{"text_tokens":718,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":2464,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":718,"tokens_out":79,"duration_ms":23890,"temperature":1.0,"reasoning_tokens":2464,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-06-27T20:43:00.274028+00:00","model_set":{"reader":"grok-4.3"},"falsifier":"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.","supporting_citations":[],"review_version":1}