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rUv 50029d6eb2 research(R15): RF biometric primitives — 5 environment-invariant features with quantified discriminability (#717)
Catalogues 5 biometric primitives in CSI that survive cross-environment
transfer by physical construction (not just statistical learning), with
quantified discriminability:

| Primitive                          | Bits | Invariance |
|------------------------------------|-----:|------------|
| Gait stride frequency              |   5  | HIGH       |
| Breathing rate + envelope          |   5  | HIGH       |
| HRV (rate-level only)              |   4  | HIGH at rate, LOW at contour |
| Body-size RCS frequency response   |   4  | MEDIUM (needs calibration target) |
| Walking dynamics (limb timing)     |   7  | HIGH (if pose works cross-room) |

Composite biometric strength: ~12-15 bits realistic vs 25-bit independence
upper bound. Enough for household + building-scale ID; insufficient for
forensic / city-scale.

R15 strengthens the R14/R3/ADR-105 privacy framework: RF biometric is
PHYSICAL not learned, so the same primitive that enables empathic
appliances is a surveillance primitive that's harder to opt out of than
visual ID. There is no behavioural countermeasure short of jamming
(illegal) or physical alteration (impossible).

Surfaces required amendment to ADR-105 federation protocol:
'The federation aggregator MUST NOT receive any raw per-subject biometric
primitive. It MAY receive aggregated, MERIDIAN-normalised model deltas.
Per-subject primitives stay on-device.'

This becomes the requirements basis for ADR-106 (deferred DP-SGD ADR).

R15 closes the last unaddressed PROGRESS.md research thread. After R15:
- Closed: 'what RF biometrics exist and how do they invariantise' = answered
- Open: ADR-106, R6.1 multi-scatterer, R3 physics-informed env prediction,
  R6.2 Fresnel-aware antenna placement

The per-occupant feature surface (R14 V1/V2/V3) is now fully grounded in
physics + constraints; remaining work is implementation, not research.

Composes with every prior thread:
- R5 saliency: primitive-specific maps
- R6 Fresnel: physical basis for RCS invariance
- R7 mincut: defends primitive-level poisoning
- R10 per-species gait: transfers to per-individual gait biometric
- R13 NEGATIVE: 5-dB-short wall rules out contour-level HRV
- R3: embedding space combines 5 primitives
- R14: all 3 verticals (V1/V2/V3) work with rate-level subset

Honest scope:
- Bit counts are upper bounds; 30-50% loss to noise/multipath
- Contour-level HRV not achievable (R13 wall)
- Walking dynamics 7-bit assumes pose-from-CSI works cross-room (unmeasured)
- Body-size RCS needs calibration target in new room

Coordination: ticks/tick-14.md, no PROGRESS.md edit.
2026-05-22 02:38:10 -04:00

4.3 KiB

Tick 14 — 2026-05-22 06:32 UTC

Thread: R15 (RF biometric across rooms) Verdict: Catalogues 5 environment-invariant biometric primitives in CSI with quantified discriminability + strengthens R14/R3/ADR-105 privacy framework. Closes the last unaddressed research-loop thread.

What shipped

  • docs/research/sota-2026-05-22/R15-rf-biometric-primitives.md — synthesis pulling from R5, R6, R8, R10, R13, R3, R14, ADR-105.

Five biometric primitives inventoried

Primitive Bits/person Cross-room invariance Status
Gait stride frequency 5 HIGH shipped (R10 DSP)
Breathing rate + envelope 5 HIGH shipped (vital_signs)
HRV (rate-level only) 4 HIGH at rate, LOW at contour partial (R13 negative on contour)
Body-size RCS frequency response 4 MEDIUM (needs calibration target) not built
Walking dynamics (limb timing) 7 HIGH (if pose works cross-room) pose pipeline shipped, cross-room unmeasured

Composite biometric strength: ~12-15 bits realistic (vs 25-bit independence upper bound). Enough for household + building-scale ID; insufficient for forensic / city-scale.

Privacy framework strengthened

R15 makes a sharper point than R14/R3: RF biometric is physical, not learned, so the same identification primitive that enables empathic appliances is also a surveillance primitive that's harder to opt out of than visual ID.

R3/ADR-105 baseline R15-strengthened
No cross-installation linkage Hardware-isolated, cryptographically proven
Embedding storage opt-in Storage of any biometric primitive opt-in (not just embeddings)
Cryptographically verifiable forgetting Forget raw primitives, not just outputs
No re-ID across legal entities No sharing of any RF biometric primitive (including aggregate / derived)

ADR-105 amendment surfaced

Adds a constraint to ADR-105 federation:

The federation aggregator MUST NOT receive any raw per-subject biometric primitive (gait frequency, breath rate, RCS curve, limb timing). It MAY receive aggregated, MERIDIAN-normalised model deltas. Per-subject primitives stay on-device.

This becomes the requirements basis for ADR-106 (deferred DP-SGD ADR from ADR-105).

Why R15 closes the loop

R15 is the last unaddressed PROGRESS.md thread. After R15:

  • Closed: "what RF biometrics exist and how do they invariantise" has a worked answer
  • Open: ADR-106, R6.1 multi-scatterer, R3 follow-up (physics-informed env_sig prediction), R6.2 antenna placement

The per-occupant feature surface (R14 V1/V2/V3) is now fully grounded in physics + constraints; remaining work is implementation, not research.

Composes with every prior thread

  • R5 saliency → primitive-specific saliency maps
  • R6 Fresnel → physical basis for RCS frequency-response invariance
  • R7 mincut → defends primitive-level poisoning
  • R10 per-species gait taxonomy → transfers to per-individual gait biometric
  • R13 NEGATIVE → 5-dB-short wall also rules out contour-level HRV
  • R3 → embedding space combines the 5 primitives
  • R14 → all 3 verticals (V1/V2/V3) work with the rate-level subset, no contour recovery
  • ADR-105 → needs ADR-106 to formalise on-device-only primitive measurement

Honest scope landed

  • Bit counts are upper bounds; realistic 30-50% loss to noise/multipath/sensor variance
  • Contour-level HRV not achievable (R13 wall)
  • Walking-dynamics 7-bit assumes pose-from-CSI works cross-room (unmeasured)
  • Body-size RCS needs calibration target in new room → ratio-only gives 3-4 bits not 5

Coordination

ticks/tick-14.md. No PROGRESS.md edit. Branch research/sota-r15-rf-biometric.

Remaining work (deferred to post-loop)

  • ADR-106: on-device DP-SGD + primitive isolation requirements from R15
  • R6.1: multi-scatterer additive Fresnel forward model
  • R3 follow-up: physics-informed env_sig prediction (zero-shot cross-room)
  • R6.2: Fresnel-aware antenna placement CLI tool

~5.4h to cron stop. 14 threads landed. PROGRESS.md research agenda exhausted.

Next-tick plan

Could either:

  1. Pick up one of the deferred follow-ups (ADR-106 or R6.1 are the strongest)
  2. Start consolidating into 00-summary.md (premature; loop has ~5h left)
  3. Add a meta-analysis / loop retrospective tick

Recommend (1) on next tick — ADR-106 has clear requirements from R15 + ADR-105.