Wireless Sensing for Medical Applications

A transmitted wireless signal travelling at the speed of light in indoor spaces goes on an intriguing journey in which it reflects off ambient objects and gets modulated by human motion before reaching the receiver. Leveraging this fundamental principle, this thesis exploits radio signals from commercial wireless devices to enable novel health sensing applications. The practical outcomes of this work range from wireless-based physiological vital sign monitoring to the first system for automatic tracking of Hand Hygiene practices of healthcare workers. To deliver this, we introduced techniques and algorithms to analyse human motions form reflected radio signals while addressing the practical challenges associated with the noise presence in Radio Frequency (RF) signal and the requirements of the sensing applications themselves. By relying purely on RF signals for sensing, these systems operate in a contact-less manner, agnostic to lighting conditions and can fit in residential and clinical environments without invading the privacy of the inhabitants. In effect, we show how the capabilities of commercially available RF devices can be harnessed for health and well-being sensing while addressing the downsides of alternative modalities (e.g., wearables and camera-based systems)