WI-FI TECHNOLOGY AROUND THE WORLD

Abstract

Wi-Fi signals are typically information carriers between a transmitter and a receiver. In this thesis, we showthat Wi-Fi can also extend our senses, enabling us to see Moving objects through walls and behind closed doors.
For example, we can identify the number of people in a closed room and their relative locations. We canalsoidentify simple gestures made behind a wall. Further, by combining a sequence of gestures, a humancancommunicate messages to a wireless receiver without carrying any transmitting device. The thesis introducestwo main innovations. First, it shows how one can use MIMO interference nulling to eliminate reflections off
static objects and focus the receiver on a moving target. Second, it shows how one can track a humanbytreating the motion of a human body as an antenna array and tracking the resulting RF beam. We demonstratethe validity of our design by building it into USRP software radios and testing it in office buildings