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:

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

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