A phone-based e-health system for OSAS and its energy issue

Obstructive Sleep Apnea Syndrome (OSAS) is a widespread sleep-disordered breathing disease, which leads to repetitive hypoxemia, hypercapnia and interruptions of the normal sleep pattern. Considering its severe negative impact on human health, long-term monitoring of OSAS is necessary. Current OSAS monitoring systems require patients to stay in the hospital overnight and need considerable wiring between human body and the system. In this work, we propose a smartphone-based, wireless e-health system designed for OSAS. Our design offers a portable system that enables anytime and anywhere monitoring. Our experiments and modeling show that energy efficiency is the major bottleneck for sustainable operations of this battery-driven system. On the solution side, we can make full use of the low-power mode of Bluetooth, which is proved to be the energy bottleneck. The lifetime of the resulting OSAS system would increase by more than 50%. Our ongoing work seeks to take a holistic approach to more energy-efficient system.