In this context, key components of the IoT will be RFID
systems [20], which are composed of one or more reader(s)
and several RFID tags. Tags are characterized by a unique
identifier and are applied to objects (even persons or animals).
Readers trigger the tag transmission by generating
an appropriate signal, which represents a query for the
possible presence of tags in the surrounding area and for
the reception of their IDs. Accordingly, RFID systems can
be used to monitor objects in real-time, without the need
of being in line-of-sight; this allows for mapping the real
world into the virtual world. Therefore, they can be used
in an incredibly wide range of application scenarios, spanning
from logistics to e-health and security.