wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

Communications in Medical Applications 30-7
30.4.4 Bluetooth
Although requiring more power than IEEE 802.15.4-based communications, Bluetooth has found
applications in ambulatory medical monitoring [23], mobile care alert systems [24], and in physiological
monitoring [25]. The ambulatory monitoring solution presented by Zhang and Liu addresses the
replacement of traditional holter systems by real-time ones. Traditional holter systems store physiological
data in a local memory that is later downloaded onto a PC for diagnosis. This approach endorses the
occurrence of a wide range of errors that can only be detected after downloading the holter data (e.g.,
lead malfunction). As such, the authors propose a monitoring architecture where several patients can
be monitored through the use of Bluetooth-enabled sensors communicating with a PC using Bluetooth
asynchronous connectionless (ACL) links.
Lee et al. put forward a mobile care alert system allowing the monitoring of hypertension and
arrhythmia patients, triggering early warning notifications when abnormal parameters are detected.
This system encompasses a front-end personal mobile device and a back-end care center server. The first
comprises a physiological (blood pressure, pulse, and ECG) parameter extraction Bluetooth-enabled
device and a mobile phone. The second consists of a GSM/GPRS module (able to transmit/receive short
messages) and a PC-based care center host with an Internet connection. The system operates by periodically
sampling physiological signals performing its transmission to a Bluetooth-enabled mobile phone
(device) using the RFCOMM transport protocol, which emulates RS232 serial ports over the (Bluetooth)
L2CAP protocol. Besides uploading the physiological data to a database in the healthcare center server,
the mobile phone uses a simple algorithm to identify abnormal conditions, which result in the transmission
of short messages to the physicians or the other healthcare providers. Abnormal conditions (identified
by professional judgment of the stored information in the healthcare center server) trigger an alarm
to the related personnel, for example, local officers can be instantly informed or an ambulance can be
immediately dispatched to the location of the patient for rescue.
Stojanovic et al. proposed a physiological monitoring system with an architecture comprising
Bluetooth-enabled sensors worn by patients, a Bluetooth access point, and a local server. The major
difference from the system proposed by Lee et al. is that the patient-worn integration device is here
replaced by an access point. As such, if the patient wears multiple Bluetooth-enabled sensors, there will
be multiple RFCOMM links to the access point, which acts as a wireless multiserial server that receives
serial data over the Bluetooth RFCOMM links and packs it in TCP/IP frames that are sent to the local
server and to other remote locations (e.g., hospital), using the Internet, if required.
As suggested by the aforementioned examples, Bluetooth has been identified as a feasible PAN technology
to support medical sensor-based applications. In consequence, the Bluetooth Special Interest
Group (SIG) developed a specific Medical Device Profile (MDP) [26] aimed at expanding the use of the
technology into the medical, health, and fitness markets. The MDP addresses a wide variety of medical
devices (blood pressure meters, weight scales, pulse oximeters, glucose monitors, pulse/heart rate monitors,
etc.), supports multiple data transfer modes (real-time streaming, periodic, episodic, and batch
transfer), and is able to cope with tight synchronization requirements (1.ms). Data communications use
the exchange specifications and the data structures defined by the IEEE 11073 [53] protocol on top of the
MDP layer, thus enabling data sharing between applications and improving interoperability between
medical data endpoints.
30.4.5 IEEE 802.11
The IEEE 802.11 protocol has been widely adopted in wireless LANs addressing home and business
application scenarios. Given its target application domain (power consumption characteristics), it is not
commonly used for supporting small form factor monitoring devices requiring a high level of autonomy.
Nevertheless, there are reported results of using IEEE 802.11 for physiological data collection [27].
However, due to its pervasiveness, it is frequently adopted as the enabling technology for gateways in
© 2011 by Taylor and Francis Group, LLC