To deal with the problem of an aging population and the increasing number of chronic patients in China, Poon and Zhang (2008) developed a four-layer (personal, home, community, and hospital) m-health application framework for their application based on
mobile devices. They took management of BP (blood pressure) as an example and described wearable intelligent sensors and personal healthcare information systems. In the four-layer system, the medical costs were reduced in two aspects: lower equipment costs and reduced use of medical facilities through new techniques that provided precise diagnosis and targeted therapy. The result of the paper was that innovative technologies in wearable medical devices and BANs (Body Area Network) can be developed to collect information, thus it could provide affordable healthcare for both urban and rural residents. In this case, mobile phones worked for displaying BP.