Technical deep-dives on WiFi CSI sensing — each post covers one angle the pillar pages do not. For the structured guides, start with how it works , the sensing pipeline , and the detection ladder .
Wavey also publishes research on the adversarial mirror of WiFi sensing — detecting and mitigating unauthorized RF surveillance:
802.11bf standardizes WiFi sensing but leaves privacy protection vendor-dependent. No mandatory secure-LTF for sensing NDPs, no opt-out mechanism, and BFI remains plaintext — what enterprise buyers and researchers need to know.
How to prevent unauthorized WiFi sensing — CSI fuzzing, intelligent reflecting surfaces, BFI obfuscation, and anti-sensing shields. What each defense achieves, what it costs, and why detection and mitigation must work together.
Five detection layers for unauthorized RF sensing — from emitter inventory to behavioral baselines. What works today on ESP32 mesh, what remains open research, and why passive sniffer detection is the hardest problem.
NDSS 2025 and CCS 2025 proved passive WiFi surveillance is practical — occupancy detection at 20m through walls, identity inference across 197 subjects, all from plaintext beamforming feedback on commodity hardware.
WiFi CSI sensing works both ways — the same physics that detects occupancy without cameras also lets an attacker observe a room without consent. What the research says and why RF privacy is an unserved problem.
What ESP32 CSI actually gives you — sampling rate, antenna count, phase noise floor, ESP-CSI API surface, and when cheap hardware is enough for real sensing.
Empty-room CSI fingerprinting, furniture drift, cross-site domain shift, adaptive baselines, and when to re-baseline — the engineering behind reliable occupancy sensing.
A practical path from variance thresholds to spectrogram CNNs for WiFi HAR — label collection, training, evaluation, and why transfer learning across rooms fails without adaptation.
What one CSI matrix actually looks like — OFDM structure, multipath superposition as a worked example, and why RSSI discards the degrees of freedom that make WiFi sensing possible.
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