Low-latency indoor localization using bluetooth beacons

Indoor localization refers to the task of determining the location of a traveler in spaces (such as large building complexes or airport terminals) using coordinates appropriate to those spaces (such as floor and room number or airport terminal and gate). Indoor localization using Bluetooth beacons is attractive because of the low cost and high spatial selectivity of Bluetooth devices. However, a significant drawback of the Bluetooth protocol for this application is the large delay incurred in the discovery phase of the protocol, which is the phase used for detecting beacons. These delays, of approximately 20 seconds, hamper the use of this localization method because typical walking speeds are likely to change the set of potentially visible beacons part-way through the discovery phase. We study the causes of these delays and propose methods for alleviating them for indoor localization applications. We formalize the key problem of finding a minimum-cost complete beacon-probing plan and present an algorithm for generating such plans.