Low power Wi-Fi for mHealth applications

Abstract

It is thought that we are heading into the 4th industrial revolution of cyber-physical systems with an increasing number of economic and social opportunities which will heavily rely on the machine-to-machine (M2M) paradigm. In this work, the concept of the Internet of Things (IoT) is applied to a healthcare environment where a wireless, autonomous device is built to enable a continuous, remote body health monitoring system. Driven by the need for portability and seamless connectivity, attention is given to the currently available IEEE 802.11 Wi-Fi standard as a viable wireless method of communication in such a system, investigating the patterns of power consumption generated by this standard and methods of how one can retain its several benefits but consume less energy. Thus, the approach necessary to collect, transmit and store wirelessly body sensor data in a power efficient and reliable method via Wi-Fi is investigated. A comparison of energy consumption is made between standard and low power Wi-Fi in different operational modes. A model of a body sensor system was developed where heart rate sensor values were uploaded to a webserver via both standard and low power Wi-Fi modules. The obtained results clearly show that when low power Wi-Fi is used, energy consumption is significantly reduced in a manner that makes it suitable to be used in an mHealth application. It was also determined that low power Wi-Fi does not necessarily constrain a short range of the system from an access point. Using a 3.7V, 850mAh battery and transmitting 3 sensor values every 300s, the battery life when using low power Wi-Fi lasted 4.81days as opposed to 2.51days when using standard Wi-Fi. This makes low power Wi-Fi nearly twice more efficient than standard Wi-Fi.