Aging in Place — Resident A
Reconstructing within learned normal distribution · Hallway · baseline learned over 26 days
Home — Camera-Free RF CoverageCSI-inferred skeleton
Hallway
FallNet Reconstruction Erroranomaly, not classification
0.24 / 0.62
Recon Error
0.245
Peak Accel
2 m/s²
Θ Threshold
2.5 m/s²
Segments
0
Falls are accidents, not reproducible signatures. The model learns this resident's repeatable activities and flags anything the autoencoder cannot reconstruct — no fall labels required.
Front-End Signal Chain
1. CSI Amplitude
Amplitude only — phase discarded as unstable across NICs
2. Conjugate Multiply
Denoise by conjugate multiplication across antenna pairs
3. Channel Dynamics
Cosine similarity between consecutive subcarrier vectors
4. Segmentation
Acceleration threshold Θ = 2.5 m/s² cuts candidate events
5. STFT
Short-time Fourier transform of the segment
6. FallNet
Autoencoder reconstruction error scores abnormality
Inactivity Watch
Kitchen
expected 09:00 · last 07:12
Bathroom
expected 08:30 · last 07:04
Hallway
expected 08:00 · last 11:41
Bedroom
expected 07:00 · last 07:02
Recent Events
SiFall Benchmarkspublished
Real-world tests
98.3%
3-day continuous
94.1%
False alarms (3 d)
1
Detection ladder
Rung 6