{"id":"d880f00f-ecc9-4de7-8491-77a9f030cabd","arxiv_id":"2606.31466","paper_version":2,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":5.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":0,"one_line_summary":"Optimizes rotatable antenna pointing vectors in ISAC systems to maximize minimum echo power over a sensing region subject to user rate constraints, deriving a closed-form solution for the single-user far-field case and an alternating optimization algorithm for the general multi-user case.","lead":"This paper proposes optimizing the orientation of rotatable antennas at a base station to improve integrated sensing and communication performance. A smart generalist might read it to see how flexible antenna designs could help future wireless systems handle both data transmission and target detection more effectively.","discovery_kind":"new_application","skeptic_critique":{"model":"grok-4.3","headline":"No significant objection identified","rationale":"Reader correctly flagged the far-field assumption but it applies only to the special-case closed-form, not the simulation claim for the general AO algorithm. No other load-bearing technical risk is detectable from the given material.","tokens_in":1724,"tokens_out":205,"duration_ms":18918,"concrete_test":"Reproduce the AO iterations from the general-case description and compare final min echo power against the array-wise rotation benchmark on the same channel realizations; if the gap disappears under identical random seeds, the outperformance claim is sensitive to implementation details.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The abstract outlines a standard AO framework for the general multi-user extended-target case and a far-field closed-form for the single-user point-target special case. The central claim rests on simulation outperformance versus benchmarks. No internal inconsistency, hidden assumption, or unsupported step is visible in the provided description that would undermine the simulation-based claim.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.3","summary":"The manuscript presents an approach to optimize the orientation of rotatable antennas (RAs) in an ISAC system at the base station. The goal is to maximize the minimum echo signal power in a sensing region subject to communication rate constraints for multiple users. For the special case of single user and point target in the far-field, all RAs have the same optimal orientation, for which a closed-form solution is derived. For the general case, an alternating optimization algorithm is proposed that iterates over transmit beamforming, probing signal covariance matrix, and RA pointing vectors. Simulation results show that the proposed system outperforms benchmarks including array-wise rotation optimization and fixed antenna orientation.","tokens_in":1784,"tokens_out":334,"duration_ms":24780,"significance":"If valid, the paper demonstrates the value of antenna rotation as an additional degree of freedom in ISAC systems, providing both a closed-form solution in a special case and a practical AO algorithm for the general case. The simulation results supporting outperformance over several benchmarks add to the evidence for the benefits of flexible antenna architectures. The derivation under standard far-field assumptions aligns with existing literature without introducing circularity.","major_comments":[],"minor_comments":[{"comment":"Consider including quantitative performance improvements (e.g., percentage gains in echo power) in the abstract to better highlight the results.","section":"Abstract"},{"comment":"The figures would benefit from error bars or multiple Monte Carlo runs to indicate variability in the reported outperformance.","section":"Simulation Results"},{"comment":"Check for consistent use of notation for the pointing vectors and channel models throughout the paper.","section":null}],"recommendation":"minor_revision","confidential_remarks":null},"author_rebuttal":{"model":"grok-4.3","summary":"We thank the referee for the positive assessment of the manuscript, the accurate summary of its contributions, and the recommendation for minor revision. No major comments were provided in the report.","responses":[],"tokens_in":1301,"tokens_out":54,"duration_ms":9475,"standing_objections":[]},"desk_editor":{"model":"grok-4.3","letter":"The core contribution is the application of per-antenna rotation to ISAC. For the special case of one user and one point target in the far field, all antennas end up with the same orientation and the optimal pointing vector has a closed form. For the general multi-user extended-target setting the authors give an alternating optimization that cycles through beamforming, probing covariance, and the individual pointing vectors.\n\nThe simulations are the main evidence offered. They report clear gains over fixed-orientation baselines and over array-wise rotation, which matches what one would expect once extra spatial DoFs are added. The far-field assumption that enables the closed-form result is stated explicitly and is the main modeling restriction.\n\nNo internal contradictions appear in the abstract or the stress-test note. The work stays within standard far-field channel models and convex steps rather than introducing fitted parameters. That keeps the circularity burden low.\n\nThis is incremental but honest progress inside the ISAC-plus-flexible-antenna niche. Readers already following FAS/MA/pinching-antenna papers will find the extension straightforward to understand and the algorithm usable as a starting point. It is not aimed at readers outside that subfield.\n\nI would send it to peer review. The special-case result and the simulation comparison are concrete enough to merit referee time, even if the general-case algorithm is standard AO.","headline":"This paper adds a closed-form far-field result for single-user point-target ISAC with rotatable antennas plus an AO algorithm for the multi-user extended case, backed by simulations that beat the listed benchmarks.","tokens_in":2272,"tokens_out":357,"would_cite":false,"duration_ms":13599,"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":"Rotatable antennas at the base station can be oriented to maximize minimum sensing echo power in ISAC systems while satisfying user communication rates.","keywords":["rotatable antenna","ISAC","antenna orientation","beamforming optimization","alternating optimization","sensing echo power"],"falsifier":"A simulation or measurement in the near-field region where the derived closed-form pointing vector fails to maximize the minimum echo power.","tokens_in":2630,"feed_emoji":"📡","tokens_out":476,"duration_ms":23411,"temperature":0.7,"pith_summary":"This paper explores deploying an array of rotatable antennas at the base station for integrated sensing and communication. The goal is to optimize antenna orientations along with beamforming to maximize the weakest sensing echo in a region, while keeping communication rates above thresholds for multiple users. In the special case of one user and a point target far away, all antennas should point the same way, and a closed-form solution gives the best direction. For the general case, the authors develop an alternating optimization procedure that cycles through beamforming, signal covariance, and antenna pointing. Numerical tests show this approach beats systems with fixed antennas or only array-level rotation.","feed_headline":"Rotatable antennas raise ISAC sensing echo power","feed_subtitle":"Per-antenna orientation optimization with alternating algorithm outperforms fixed and array-wise schemes while meeting rate constraints.","key_machinery":"Alternating optimization of transmit beamforming, probing signal covariance matrix, and individual RA pointing vectors.","core_discovery":"The paper shows that by allowing individual rotation of each antenna in the array, the ISAC system gains extra degrees of freedom that can be exploited through joint optimization of orientations and signals to achieve higher sensing performance under communication constraints, with a closed-form solution available when users and targets are in the far field.","pith_inferences":["Similar optimization could apply to other flexible antenna architectures like movable antennas.","Performance gains might diminish in near-field scenarios where the far-field assumption fails.","Extending to dynamic targets or mobile users would require additional tracking mechanisms."],"forward_implications":["Simulation results show significantly higher minimum echo signal power than benchmark schemes.","The closed-form solution provides optimal identical orientations for far-field single-user point-target cases.","The AO algorithm converges to better solutions than array-wise rotation optimization."],"fun_headline_variants":["RA orientations optimized for higher ISAC sensing power","Per antenna rotation in ISAC via alternating optimization","Closed-form solution for far-field RA ISAC optimization","Joint beamforming and RA orientation optimization in ISAC"],"cache_read_input_tokens":2112,"weakest_assumption_plain":"The communication user and sensing target lie in the far-field region, which allows the optimal antenna orientations to be identical and admits a closed-form solution.","fun_headline_variants_meta":{"raw":{"variants":["RA orientations optimized for higher ISAC sensing power","Per antenna rotation in ISAC via alternating optimization","Closed-form solution for far-field RA ISAC optimization","Joint beamforming and RA orientation optimization in ISAC"]},"model":"grok-4.3","cost_usd":0.007995,"raw_usage":{"total_tokens":3558,"prompt_tokens":666,"num_sources_used":0,"completion_tokens":59,"cost_in_usd_ticks":79953000,"prompt_tokens_details":{"text_tokens":666,"audio_tokens":0,"image_tokens":0,"cached_tokens":64},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":2833,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":666,"tokens_out":59,"duration_ms":19134,"temperature":1.0,"reasoning_tokens":2833,"cache_read_input_tokens":64,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-03T22:11:18.620314+00:00","model_set":{"reader":"grok-4.3"},"falsifier":"A simulation or measurement in the near-field region where the derived closed-form pointing vector fails to maximize the minimum echo power.","supporting_citations":[],"review_version":2}