Towards Real-Time Fine-Grained Tracking in Distributed Large-Scale RF Tag Systems

Michigan State University, East Lansing MI

Investigators

Abstract

A scalable wireless system that can continuously, accurately, and simultaneously track multiple people's movements and detect their fine-grained body motions will enable the development of many novel real-life applications, such as diagnosing movement disorders, continuously monitoring children's behaviors, and alerting caregivers of elderly falls in real time. The objective of this project is to design and implement such a wireless tracking system by employing radio frequency (RF) tag based wireless sensing technology. A team of researchers from Michigan State University will address the fundamental challenges in both theory and experiments through innovations in signal processing, mathematical modeling, algorithm and protocol design, machine learning, optimization, radar design, and harmonic tag fabrication. The wireless tracking system will make it possible to monitor the activities of elderly residents in nursing homes while preserving their privacy, predict and prevent their possible falls, and guide them to perform doctor-suggested exercises. It will also enable the continuous monitoring of children’s behaviors and activities in a non-invasive manner, making it possible to conduct data-driven studies of children’s physical and mental development. The research findings will be broadly disseminated to research community for reproducibility of results, and educational materials will be created to enrich students’ learning experience. This project aims to design and implement a scalable wireless tag tracking system that features large coverage area, distributed sensing, inter-reader coordination, simultaneous multi-tag tracking, and high resolution in time. It comprises three complementary research thrusts. The first thrust will develop fine-grained tracking solutions for a large-scale tag tracking system by coordinating and synchronizing location-distributed radio frequency (RF) readers for precise localization. It will develop new techniques to maximize the time resolution of tag tracking through optimizing signal processing algorithms, inter-reader communication and coordination protocols, tag scheduling, and resource allocation. The second thrust will develop techniques to enable simultaneous multi-tag tracking similar to the idea of multi-user MIMO (multiple-input and multiple-output) in cellular networks. It will significantly improve the time resolution of tag tracking, especially in tag-dense scenarios. The third thrust will focus on motion tracking using narrowband harmonic tags and micro-Doppler radar. It will advance the design and fabrication of harmonic RF tags and radars for frequency-selective multi-tag operations, and explore the performance limits of harmonic tags in tracking applications. In addition, this project includes a strong component of system implementation and experimental evaluation, with the ultimate goal of demonstrating its real-life applications. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.