Modeling signal strength of body-worn devices

Body-wearable devices for physiological monitoring are fast becoming a reality — by 2014, 420 million wearable wireless devices are expected to be in use, of which 90% will be for sports and fitness applications. We envisage the use of ultra-lightweight wearable devices for monitoring athletes in field sports such as soccer for quantifying, assessing and improving game performance. To this end, in this paper we present an empirical characterization of the radio signal strength of sensor devices mounted on an athlete's body. We fit simple analytical models to our empirical data, highlighting how the signal degrades with distance as well as orientation of the body. Our model aids in improved protocol design and locationing services that take into account propagation effects of the human body.