6Fit-A-Part: A Protocol for Physical Distancing on a Custom Wearable Device
Yifeng Cao, Ashutosh Dhekne, Mostafa Ammar
Abstract
The coronavirus pandemic is altering our way of life. As more establishments open, there is an expectation that people will follow physical distancing guidelines. The implementation, however, is poor; just putting up warning signs appealing the general public to keep a distance of 6 feet from others is hardly enough. In this paper we consider the design of a wearable device that raises an alarm if another similar device is detected within a set distance. It uses off-the-shelf ultra-wideband radio technology for real-time, accurate distance estimation from others in the vicinity. We design an one-to-all ranging protocol that is able to accurately estimate distance to neighboring devices and warn the user if the distance falls below a certain established threshold within a short time. The device must compensate for human occlusions and avoid unnecessary warnings when physical barriers exist between devices. We implement and evaluate our protocol in a small testbed with custom prototype hardware as well as in simulation. Our ranging protocol is capable of performing up to 10 distance measurements per second, while avoiding packet collisions. The overall percentage of rangings completed is around 65% in a 10-node network, and the distance accuracy is around 20cm even with frequent human occlusions. We believe this prototype will provide the first steps to ensure physical distancing in various real-world settings.