Description
Detecting that an unauthorized person has entered a monitored space using the disturbance their body causes to existing wireless infrastructure. As a physical security problem this is a specialized case of motion-detection / presence-detection with policy semantics layered on top: who is allowed where, when. Note that "intrusion detection" in network-security literature refers to a different problem (NIDS/IDS) — the wireless-sensing variant is a small, distinct cluster.
Why it's hard
- High false-positive cost — an alarm system that cries wolf gets disabled by users.
- Zero-knowledge attacker model: the intruder may know the sensor placement and move slowly.
- Cross-site generalization is poor for the same reasons as the rest of CSI sensing.
- Integration with access-control systems (authorized vs intruder distinction) requires fusion with identity.
Common approaches
- CSI variance / change-point detection with adaptive baselines.
- Subspace-based intruder-direction estimation.
- Combination with PIR or door-contact sensors for confirmation.