Biomedical Engineering Reference
In-Depth Information
Wireless
Links
Medical
Database
Sensor nodes
(Implantable/
Wearable)
Internet Cloud
Wired Network
Coordinator
or
Router
Monitoring
Station
PDA
Fig. 1 Key components of a wireless body area network (WBAN)
examples of medical applications that can be implemented using WBAN techniques.
WBANs can also be used for non-medical applications such as gaming and smart
home control.
Several key components can be identified in a WBAN system for health care
monitoring applications. Sensor nodes are either implantable or on-body devices
that transmit vital physiological information, such as ECG, electroencephalogram
(EEG) and body temperature to an outside node.
A coordinator node or a router node is used to collect and route the information
sent by a sensor node and forward that information to a computer-based application
for interpretation [ 2 ]. Figure 1 illustrates the key components of a WBAN.
A WBAN used for health care monitoring inherits several key requirements. An
implanted or on-body sensor node is battery powered. Especially in the implantable
case, human intervention in replacing the batteries should be kept at a minimum
level, since it might involve surgical procedures. Hence, a WBAN sensor node should
consume low power. Low power transmission of signals limits the communication
range (usually 0.1-2 m). As a result, an optimized low complexity medium access
control (MAC) protocol should be used in WBANs so that it would enhance the low
power operation of the sensor node.
A WBAN network structure consists of several tiers of interconnecting networks.
This chapter pays attention to the communication between the sensor nodes and an
immediate parent node of the sensor nodes, which can either be a central coordinator
or a gateway router. This communication is named as sensor tier communication here-
after. Typically, short-range wireless communication of less than 2 m is employed in
the sensor tier. This sensor tier is characterized by the following features:
The sensors are connected to the gateway in a star topology.
The sensor nodes have limited processing capabilities and very stringent require-
ments on power consumption.
 
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