A Review of IoT-Enabled Mobile Healthcare: Technologies, Challenges, and Future Trends

The Internet of Things (IoT) has grown over decades to encompass many forms of sensing modalities, and continues to improve in terms of sophistication and lower costs. The trend of hardware miniaturization and emphasis on user convenience has inspired numerous studies to integrate more varied devices within the IoT into modernizing healthcare systems, facilitating applications, such as activity recognition, fitness assistance, vital signs monitoring, daily dietary tracking, and sleep monitoring. These applications are vital for prevention, detection, and treatment of ailments and can be realized using both dedicated health sensors as well as general-purpose sensors not originally designed for health monitoring. This article surveys such studies, detailing smart health monitoring systems, and the types of sensor components utilized within the IoT. We categorize and analyze these works based on their leverage of device-based techniques (i.e., use of sensors worn or carried by the person) and device-free techniques (i.e., wireless sensing without need to carry hardware), as well as signal processing and classification techniques utilized. In particular, we discuss how different combinations of these techniques can be creatively applied to support professional and commercial health-monitoring IoT networks. We also identify limitations and potential directions that future research may explore.