Wearables and phone tracking sense devices. WiFi CSI senses bodies. The coverage and data models are fundamentally different.
What gets detected
| Wearable / phone tracking | WiFi CSI | |
|---|---|---|
| Signal source | BLE beacon, UWB tag, WiFi probe/MAC | Body perturbation of radio channel |
| Requires cooperation | Yes — person carries device | No — device-free |
| Misses | Anyone without the device | No one in RF coverage |
| Identity | Device ID (often personal data) | Anonymous — no identifiers |
A guest, child, intruder, or elder who forgot their pendant is invisible to device tracking. CSI detects any body that perturbs the channel.
Data model
Phone/MAC analytics produce device-level events: “MAC xx:xx connected,” “beacon seen.” Counting people requires mapping devices to humans — one person with three devices inflates count; five people sharing one laptop undercounts.
CSI analytics produce space-level events: “zone occupied,” “motion intensity 0.7.” No device mapping needed. See occupancy analytics .
Privacy and compliance
MAC addresses and persistent device identifiers can constitute personal data under GDPR. CSI occupancy data — zone-level utilization without identifiers — sits in a different regulatory category, closer to anonymous people-counting beams.
Maintenance burden
Wearables: charging, pairing, replacement, compliance (“please wear this”). Per-person operational cost scales with occupancy.
CSI nodes: fixed installation, zero per-person maintenance. Operational cost is per-zone, not per-person.
When to choose which
Wearable: opt-in personal health metrics (heart rate, steps, SpO2), workforce safety with assigned devices, clinical trials with consenting participants.
WiFi CSI: space-level occupancy, elder-care ambient monitoring, security, building analytics — anywhere you need to sense everyone in a zone without asking them to carry anything.
See elder-care monitoring and security & intrusion .