The rise in life expectancy and the consequent progressive aging of the population, with a prevalence of certain diseases, trigger a careful thinking on the role and modes of providing care to people in order to ensure a decent quality of life, without imposing traumatic changes of habits and domestic environment. The remote monitoring and support thus become strategic tools to implement social policies over the long term. In this sense, the ability to pervasively, discreetly, and generally uncooperatively quantify the health conditions and the human interactions with the environment is the first step to provide all the information required to adapt already established healthcare protocols to new needs. The emerging paradigm of GSM and a wide variety of increasingly cheap sensors (wearable, implanted, and environmental) have the potential to put in place personal Smart-Health systems hosting new interconnections between the natural habitat of the person, his body, and the Internet at the purpose to produce and manage “participatory” medical knowledge . By displacing wireless sensors inside the home, on clothes and personal items, it becomes possible to monitor, in a way that preserves the privacy, the macroscopic behavior of the person as well as to compile statistics, to identify precursors of dangerous behavioral anomalies, and finally to activate alarms or prompt for remote actions by appropriate assistance procedures. Among the various technologies that potentially converge to this scenario, RF identification (RFID) systems may represent a strategic enabling component thanks to the energy autonomy of battery-less tags. Furthermore, their low cost is compatible with a widespread distribution and disposable applications.
A passive RFID system is composed of a digital device called tag, embedding an antenna and an IC-chip with unique identification code (ID), and a radio scanner device, called reader. Despite the RFID technology is currently mostly applied to logistics of goods, the very recent research is exploring other paths with the common goal of extracting physical information about tagged objects and nearby environment through low-level processing of electromagnetic signals received and backscattered by the tags. RFID systems could, therefore, permit to implement, in a simple and efficient way, the last few meters of the IoT concerning the pervasive quantification of the person’s interaction with the environment.
This paper is aimed at drawing a landscape of the current research on RFID sensing from the perspective of IoT for personal healthcare. The survey will cover passive (i.e., battery-less) devices in the UHF band (860–960 MHz) which are capable to provide services and enough read ranges to implement a network of sensors for tracking the human wellness and monitoring the quality of the local environment. The discussion will cover both the physical issues and the signal processing, up to the application level.
An RFID-powered environment supporting new pervasive healthcare services could be a Smart-House equipped with a distributed network of readers, enforcing a uniform and robust coverage  in the most relevant spaces, and anheterogeneous set of battery-less tags with sensing capability. Readers may interact, for instance, through WiFi or Bluetooth links, with a concentrator node enabling the interconnection with external services that take care of data processing and of assistance procedures’ activation. Data gathered from the RFID environment, e.g., generated by ambient tags or by the interaction of the user with the house, could be finally processed by means of data-mining algorithms to analyze the movements and trajectories of the user, classify its gestures in daily and sleep conditions, recognize critical events and emit alarms