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between different devices.
2.1 The Origins: RFID
The technological structure of NFC systems is quite
the same as the one of RFID systems. NFC uses the
same physical principles and partly the same kind of
devices.
It’s therefore difficult to understand the structure
and the possible uses of NFC with investigatinga little
the main features of Radio Frequency Identification
technology.
RFID is an automatic identification technology
which uses the electromagnetic field as the mean of
identification (Finzkeller, 2003). Usually RFID sys-
tems are composed by two devices: a Reader, which
generates the interrogating electromagnetic field, and
the Transponder, which is located on the item to be
identified and returns back to the reader the ID (Iden-
tification) code and the additional information.
When the Transponder comes inside the EM
(Electromagnetic) field of the reader it can be inter-
rogated and it can send back the data using the same
field.
There are many kinds of RFID systems, working
at different operativefrequencies. In particular we can
find Low Frequency (125-135kHz), High Frequency
(13.56MHz), Ultra High Frequency (868-915MHz)
and Microwave (> 2GHz) systems.
Every different RFID application needs a particu-
lar care in the choice of the right technological solu-
tion: for example even if Ultra High Frequency sys-
tems can provide large read ranges, they have a lot of
problems od electromagnetic compatibility.
The same happens for the powering methods of
the transponders: in fact we can find passive, active or
semipassive transponders, offering very different fea-
tures. While an active transponder can be read from a
distance ten times wider than a passive one, his higher
price can make it unsuitable in applications in which
the number of items to be identified is very high.
2.2 NFC Technological Features
NFC belongs to the family of RFID, but it has specific
technological features (Innovision, 2007).
It only works at the frequency of 13.56MHz, that
is an unregulated band. This means there aren’tany li-
censes required and restrictions concern only the elec-
tromagnetic emissions, in order to limit the impact of
the system on human body.
Differently from traditional RFID technology,
passive and active devices can be integrated into the
same system.
NFC can reach a maximum read range of around
20cm but common devices are not able to read from
distances larger than 4 or 5cm. The decision to create
products with low read ranges comes not only from
the physic limitations of the technology but also from
the fact that short ranges ensure a bigger protection
from outside intrusions. These requirements mainly
come from the aim to use NFC to implement proxim-
ity wireless payment systems.
NFC devices can currently communicate at three
different speeds, 106kbit/s, 212kbit/s and 424kbit/s
but in the future higher rates will be probably
achieved.
NFC protocol differentiates the device initiating
and controlling the communication, called Initiator
and the device answering the request from the initia-
tor, called Target (ECMA, 2007).
NFC protocol also presents two different opera-
tive modalities: a passive mode, with a single device
generating the field and the other one using this field
to exchange the data, and an active mode, in which
the two devices generate their own EM field.
As a consequence NFC devices have studied to in-
tegrate on the same support the functions covered by
the Reader an the Transponder. This means that we
can have three different types of communication:
• The traditional communication protocol of RFID
systems, in which the NFC equipped device acts
as a Reader and it can get the information stored
onto a Transponder and can also write on it.
• A bidirectional communication, in which two
NFC devices exchange data between themselves.
This case is particularly interesting because, even
if the bit rates currently available are not too high,
the particular protocol implemented makes the es-
tablishing of the communication very easy.
• A communication between a turned on device and
a turned off one. In this case the second item
is seen by the first one simply as a Transponder,
making it suitable for identification and access
control purposes.
All these different methodologies of data ex-
change have brought to the realization of many kinds
of systems covering a wide range of applications not
only in the field of identification but also in the one of
personal communication.
Moreover, the short reading range of the devices
makes NFC systems considerably safe, because in-
truders should arrive too much close to the devices
to steal the data.
The large number of possible applications has fi-
nally led to the integration of the NFC technology
onto the most common communication devices cur-
NFCARE - Possible Applications of NFC Technology in Sanitary Environments
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