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Wireless Body Area Network

PostPosted: Thu Jan 02, 2014 6:19 pm
by Prasanth
Future communication systems are driven by the concept of being connected any-where at any time. This is not limited to even in medical area. Wireless medical communications assisting peoples work and replacing wires in a hospital are the applying wireless communications in medical healthcare. The increasing use of wireless networks and the constant miniaturization of electrical devices has empowered the development of wireless body area networks(WBANs).In these networks various sensors are attached on clothing or on the body or even implanted under the skin. These devices provide continuous health monitoring and real-time feedback to the user or medical personnel. The wire-less nature of the network and the wide variety of sensors offer numerous new,practical and innovative applications to improve healthcare and the quality of life.The sensor measures certain parameters of human body, either externally or internally. Examples include measuring the heartbeat, body temperature or recording a prolonged electrocardiogram (ECG).


Several sensors are placed in clothes, directly on the body or under the skin of a person and measure the temperature, blood pressure, heart rate, ECG, EEG, respiration rate, SpO2 levels etc. Next to sensing devices, the patient has actuators which act as drug delivery systems. The medicine can be delivered on predetermined moments, triggered by an external source or immediately when a sensor notices a problem. The sensor monitors a sudden drop of glucose, a signal can be sent to the actuator inorder to start the injection of insulin. Consequently, the patients will experiences fewer nuisances from his disease. An example of a medical WBAN used for patient monitoring.

A WBAN can also be used to offer assistance to the disabled. For example, a paraplegic can be equipped with sensors determining the position of the legsor with sensors attached to the nerves. In addition, actuators positioned on thelegs can stimulate the muscles. Interaction between the data from the sensors andthe actuators makes it possible to restore the ability to move. Another example isaid for the visually impaired. An artificial retina, consisting of a matrix of microsensors, can be implanted into the eye beneath the surface of the retina. Theartificial retina translates the electrical impulses into neurological signals. Another area of application can be found in the domain of public safety wherethe WBAN can be used by firefighters, policemen or in a military environment. The WBAN monitors for example the level of toxics in the air and warns thefirefighters or soldiers if a life threatening level is detected. The introduction of a WBAN further enables to tune more effectively the training schedules of professional athletes.

The WBAN system is divided into three levels. The lowest level consists a set of intelligent sensors or nodes. These are the reduced function devise. These can only communicate with their parent device and cannot act as parent. The second level is the personal server (Internet enabled PDA, cell-phone, or home computer). These are full function devices. And they can communicate with the external network. The third level encompasses a network of remote server which is the remote application to which data or information is transferred.

A sensor node electronics is designed to detect and transmit the physiological signals listed in table 2.1.Most physiological signals are low frequency in nature and occupy a small information bandwidth. At such low frequencies and low amplitudes, some problems inherent to circuits need additional attention. For reliable information transfer it is necessary that the interface in the sensor nodes detect physiological signals in the presence of noise and increase the signal to noise ratio of the detected signal for processing by subsequent blocks of sensor nodes.