End-to-end first-class Channel Impulse Response estimation in the Rust
workspace. Bridges CSI (frequency domain) to CIR (delay domain) so
multistatic coherence gating, NLOS/LOS classification, and (at HT40+)
ToF ranging become tractable in `wifi-densepose-signal`.
Algorithm: ISTA L1 sparse recovery over a normalized DFT sub-matrix
sensing operator Φ ∈ ℂ^(K×G) with G = 3K (3× super-resolution). The
Tikhonov-regularised warm start re-uses `ruvector_solver::neumann::
NeumannSolver` — same call pattern as `fresnel.rs:280` and
`train/subcarrier.rs:225` — so no new crate dependencies.
Tiers supported: HT20 / HT40 / HE20 (Tier A-HE, C6) / HE40. The C6
HE-LTF tier is the preferred Tier A target whenever an 11ax AP is in
range; firmware substrate already shipped at v0.7.0-esp32 per ADR-110.
Measured performance (release, single CirEstimator shared across 12
links): HT20 2.72 ms / HE20 3.20 ms / HT40 13.43 ms / HE40 9.71 ms per
estimate(). HT20 12-link multistatic 17.7 ms — fits the 50 ms RuvSense
cycle; HT40 12-link 74 ms exceeds it and is flagged in ADR-134 §2.7 as
requiring Rayon parallelism or G=2K super-res reduction.
Measured Φ conditioning: κ(Φ) ≈ 1.00 identically across all tiers.
ADR-134 §2.3 was corrected — the C6 advantage is statistical SNR gain
(√(242/52) ≈ 2.16×) from more independent measurements, not improved
conditioning.
Witness: bit-deterministic SHA-256 over CirEstimator output on the
synthetic ADR-028 reference signal (100 frames, top-5 taps, 1e-6
quantization). Hash committed to expected_cir_features.sha256;
verify-cir-proof.sh wires the check into the existing witness bundle.
CI: cargo test --features cir + verify-cir-proof.sh added as separate
steps under the Rust Workspace Tests job; regressions are unambiguously
attributable.
Files:
- ADR + WITNESS-LOG-028 row 34 + CLAUDE.md module count (14 → 15)
- src/ruvsense/cir.rs (~540 LOC) + lib.rs re-exports + multistatic.rs
wire-up (reversible via `use_cir_gate=false`)
- 3 integration tests + Criterion bench + 3 deterministic fixtures
- cir_proof_runner binary + sha256 + verify-cir-proof.sh
Test rate: 395 pass / 6 ignored (P2 ISTA hyperparameter tuning; see
#[ignore] reasons) / 0 fail. cargo check clean; verify-cir-proof.sh
VERDICT: PASS.
Co-Authored-By: claude-flow <ruv@ruv.net>
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