Radio shot: Through-the-wall human recognition
In this work, we show the existence of human radio biometrics and present a human identification system that can discriminate individuals even through the walls in a non-line-of-sight condition. Using commodity WiFi devices, the proposed system captures the channel state information (CSI) and extracts human radio biometric information from WiFi signals using time-reversal (TR) technique. By leveraging the fact that broadband wireless CSI has significant number of multipaths, which can be altered by human body interferences, the proposed system can recognize individuals in the TR domain without line-of-sight path. We built a prototype of the TR human identification system using standard WiFi chipsets with 3 × 3 MIMO transmission. The performance of the proposed system is evaluated and validated through multiple experiments. In general, the TR human identification system achieves an accuracy of 98.78% for identifying about a dozen of individuals using a single transmitter and receiver pair.