Enabling high accuracy pervasive tracking with ultra low power UWB tags

Abstract

With the recent popularity of active ultra-wideband (UWB) tracking beacons, the next era of low-power IoT aims to offer tracking as a core feature in numerous enterprise and industrial applications. However, generating high-bandwidth tracking signals on cost-effective, low-power tags in a large scale deployment, poses fundamental challenges in energy-cost-performance trade-offs, not afforded by existing solutions that fall short in one or more critical dimensions. To this end, we present a novel tag design, WaveTag, whose innovation lies in taking low frequency, but high fidelity clock signals that can be generated at a very low energy footprint, and transforming them using ultra low power non-linear circuits into standards-compliant UWB preambles at desired super high frequencies (3-10 GHz UWB channels)-all without compromising on their ultra low energy footprint. We present WaveTag's systematic design, whose components address numerous technical challenges in realizing this principle in practice. Its implementation and extensive evaluation highlight WaveTag's ability to be tracked by UWB chips in our commodity devices, while operating upto 8m ranges with a tracking accuracy of under 50cm, and tracking support for upto tens of tags concurrently, each with a lifetime of about 8 years.