Precise Indoor Localization Using PHY Layer Information
This paper shows the viability of precise indoor localization using physical layer information in WiFi systems. The authors find that channel frequency responses across multiple OFDM subcarriers can be suitably aggregated into a location signature. While these signatures vary over time and environmental mobility, they notice that their core structure preserves certain properties that are amenable to localization. They demonstrate these ideas through a functional system, implemented on off-the-shelf Intel 5300 cards (that are designed to export per-subcarrier information to the driver). They evaluate the system in a busy engineering building, a cafeteria, and the university museum, and demonstrate localization accuracies in the granularity of 1m x 1m boxes, called spots.