Augmenting OFDM wireless local networks with motion detection capability

Abstract

Ubiquitous wireless local networks which use channel transfer function estimation to compensate for echoes on the wireless channel are uniquely suited for motion detection as a secondary use. In this way, added value can be provided without additional hardware. This paper presents a procedure with uses channel state information of an IEEE 802.11 High Throughput wireless link to reliably detect the presence of moving items, such as people crossing a room. By leveraging CSI instead of RSSI, the frequency-selective fading characteristic of indoor wireless channels can be taken into account while eliminating the effect of power level fluctuations in consumer-grade wireless hardware.