RF Topological Sensing — Research Index

SOTA Research Compendium

Generated: 2026-03-08 Total Documents: 12 Total Lines: 14,322 Branch: claude/rf-mincut-sensing-uHnQX

Core Concept

RF Topological Sensing treats a room as a dynamic signal graph where ESP32 nodes are vertices and TX-RX links are edges weighted by CSI coherence. Instead of estimating position, minimum cut detects where the RF field topology changes — revealing physical boundaries corresponding to objects, people, and environmental shifts. This creates a "radio nervous system" that is structurally aware of space.

Document Index

Foundations (Documents 1-2)

#	Document	Lines	Key Topics
01	RF Graph Theory & Mincut Foundations	1,112	Max-flow/min-cut theorem, Stoer-Wagner/Karger algorithms, Fiedler vector, Cheeger inequality, spectral graph theory, comparison to classical RF sensing
02	CSI Edge Weight Computation	1,059	CSI feature extraction, coherence metrics, MUSIC/ESPRIT multipath decomposition, Kalman filtering of edges, noise robustness, normalization

Machine Learning (Documents 3-4)

#	Document	Lines	Key Topics
03	Attention Mechanisms for RF Sensing	1,110	GAT for RF graphs, self-attention for CSI, cross-attention fusion, differentiable mincut, antenna-level attention, efficient attention variants
04	Transformer Architectures for Graph Sensing	896	Graphormer/SAN/GPS, temporal graph transformers, ViT for spectrograms, transformer-based mincut prediction, foundation models for RF, edge deployment

Algorithms (Document 5)

#	Document	Lines	Key Topics
05	Sublinear Mincut Algorithms	1,170	Sublinear approximation, dynamic mincut, streaming algorithms, Benczúr-Karger sparsification, local partitioning, Rust implementation

Hardware & Systems (Documents 6, 10)

#	Document	Lines	Key Topics
06	ESP32 Mesh Hardware Constraints	1,122	ESP32 CSI capabilities, 16-node topology, TDM synchronization, computational budget, channel hopping, power analysis, firmware architecture
10	System Architecture & Prototype Design	1,625	End-to-end pipeline, crate integration, DDD module design, 100ms latency budget, 3-phase prototype, benchmark design, ADR-044, Rust traits

Learning & Temporal (Documents 7-8)

#	Document	Lines	Key Topics
07	Contrastive Learning for RF Coherence	1,226	SimCLR/MoCo for CSI, AETHER-Topo extension, delta-driven updates, self-supervised pre-training, triplet edge classification, MERIDIAN transfer
08	Temporal Graph Evolution & RuVector	1,528	TGN/TGAT/DyRep, RuVector graph memory, cut trajectory tracking, event detection, compressed storage, cross-room transitions, drift detection

Analysis (Document 9)

#	Document	Lines	Key Topics
09	Resolution & Spatial Granularity	1,383	Fresnel zone analysis, node density vs resolution, Cramér-Rao bounds, graph cut resolution theory, multi-frequency enhancement, scaling laws

Quantum Sensing (Documents 11-12)

#	Document	Lines	Key Topics
11	Quantum-Level Sensors	934	NV centers, Rydberg atoms, SQUIDs, quantum illumination, quantum graph algorithms, hybrid architecture, quantum ML, NISQ applications
12	Quantum Biomedical Sensing	1,157	Biomagnetic mapping, neural field imaging, circulation sensing, coherence diagnostics, non-contact vitals, ambient health monitoring, BCI

Key Findings

Resolution

16 ESP32 nodes at 1m spacing → 30-60 cm spatial granularity
Dual-band (2.4 + 5 GHz) → 6 cm theoretical coherent limit
Information-theoretic limit: 8.8 cm for dense deployment

Computational Feasibility

Stoer-Wagner on 16-node graph: ~2,000 operations per sweep
At 20 Hz: 0.07% of one ESP32 core
Full pipeline CSI → mincut: < 100 ms latency budget

Quantum Enhancement

NV diamond: 100-1000× sensitivity improvement at room temperature
Rydberg atoms: self-calibrated, SI-traceable RF field measurement
D-Wave quantum annealing: native QUBO solver for graph cuts

Biomedical Extension

Non-contact cardiac monitoring at 1-3m with quantum sensors
Coherence-based diagnostics: disease as topological change in body's EM graph
Same graph algorithms (mincut, spectral) apply to both room sensing and medical

Proposed ADRs

ADR-044: RF Topological Sensing (Document 10)
ADR-045: Quantum Biomedical Sensing Extension (Document 12)

Implementation Phases

Phase 1 (4 weeks): 4-node POC — detect person in room
Phase 2 (8 weeks): 16-node room — track movement boundaries < 50 cm
Phase 3 (16 weeks): Multi-room mesh — cross-room transition detection
Phase 4 (2027-2028): Quantum-enhanced — NV diamond + ESP32 hybrid
Phase 5 (2029+): Biomedical — coherence diagnostics, ambient health