  Wi-Fi localization and tracking face accuracy limitations dictated by antenna
count (for angle-of-arrival methods) and frequency bandwidth (for
time-of-arrival methods). This paper presents mD-Track a device-free Wi-Fi
tracking system capable of jointly fusing information from as many dimensions
as possible to overcome the resolution limit of each individual dimension.
Through a novel path separation algorithm, mD-Track can resolve multipath at a
much finer-grained resolution, isolating signals reflected off targets of
interest. mD-Track can localize human passively at a high accuracy with just a
single Wi-Fi transceiver pair. mD-Track also introduces novel methods to
greatly streamline its estimation algorithms, achieving real-time operation. We
implement mD-Track on both WARP and cheap off-the-shelf commodity Wi-Fi
hardware and evaluate its performance in different indoor environments.
