Abstract
Low-power, low-cost accurate ranging methods implemented using narrow-band wireless (NBW) devices provide key enablement for a diverse set of applications in the vastly growing Internet of Things (IoT) and smart access control market segments. Applications of wireless ranging and localization include home and automotive access systems, indoor ranging, asset tracking, proximity sensing, distance estimation, gaming, security perimeter enforcement, and relay attack prevention to name a few. Unlike wide-band systems, NBW systems consume much lower power for each transmission and reception making them suitable for battery powered applications and possess wireless range that is an order of magnitude higher than wideband systems, allowing them to meet the requirements for several line-of-sight (LOS) and non-line-of-sight (NLOS) application conditions. An accurate multi-carrier phase-based distance measurement technique using Bluetooth-LE is described in this paper. The paper describes a practical implementation and describes some of the signal processing techniques and challenges that extend beyond existing standardized wireless protocols.