on these devices, this is the onlyway to combine the mobile phone’s NFC
and Bluetooth features. Unfortunately, using the J2ME framework,
it is neither possible to enable Bluetooth within the application
nor to set a PIN code automatically when establishing an
authenticated and encrypted Bluetooth connection [28]. Thus,
we decided to operate Bluetooth without a PIN so as to avoid
that the user has to enter the PIN code manually after touching
the device. As a consequence, the prototype did not provide an
encrypted link between the sensor device and the mobile phone.
Additionally, Bluetooth has to be activated permanently which
has a negative impact on the longevity of the battery (NFC also
needs some battery power but since NFC gets deactivated automatically
when the mobile phone is in stand-by mode, it needs
much less energy as compared to Bluetooth).
It can be expected that in future designs, these problems
will be solved by employing mobile handsets providing an improved
NFC-Bluetooth interplay. A promising way would be
to combine NFC and Bluetooth on a hardware level as presented
in [29] or at least on the mobile phone’s operating system
level. An NFC-enabled smartphone running an operating system
like Symbian (Nokia, Espoo, Finland) or Android (Google
Inc., Mountain View, CA) could execute an application with
native hardware access and solve both issues mentioned earlier.
Since the proposed solution establishes a new link each time
the sensor device is touched, it can be integrated seamlessly
into the existing NFC-based telemonitoring system. Hence, our
approach allows for acquiring all kind of health parameters in
the same way—simply by touching items or devices. Table III
gives an overview of use cases covered by this concept.
This Plug-and-Play concept without having Bluetooth paired
permanently provides two major advantages. The minimized
configuration effort of this approach allows for easy replacement
in case of a broken device. Just shipping a new device by
mail without the need of any configuration or installation procedure
would disburden patients, caretaking staff, and relatives.
Additionally, the fact of keeping the devices unpaired allows for
a multiuser scenario where devices can be shared among several
users living in the same place—each having their own mobile
phone. Those two advantages come at the prize of additional
costs for the NFC infrastructure which are expected to decrease
in the medium term due to the predicted market share of future
NFC-enabled handsets.
The multiuser scenario is realized by using the ID card to
identify and authenticate the patient. When touching the ID
card, the preinstalled application launches automatically and
connects to the remote telemonitoring system using the credentials
stored on this ID card.