Nowadays, digital electronic devices have been used to make a lot of things easier and better. Personal computers have been successful to help people in their works and to provide entertainment, thus it is not surprising if now people are thinking to make the electronic systems to be incorporated further into medical field, so that its service can be cheaper, easier to be accessed, and better in quality.
Some patients with chronic illness sometimes need to be monitored closely by medical team. By having the patients attached with suitable sensors which can transmit data over the network, it is possible for the patients to have long-term monitoring without the need for a long and expensive stay in hospital.
For long term and long distance monitoring, implantable sensors are desirable. Implantable sensors are inserted into human body so that it does not disturb the patients’ activities. Of course, the implanted devices should be able to communicate to the outside world without using wire because “wires passing through the skin are a source of infection, can result in injury (if pulled or knocked), and are often uncomfortable for the patient” . Beside the purpose of monitoring, implantable devices can also be used for more complex prescription applications, such as implantable drug delivery system, implantable insulin pump, and so on.
Figure 1.1 Wireless Body Area Network
The network for medical application around the patient’s body is termed as Wireless Body Area Network (WBAN), which can be seen in Figure 1.1. A WBAN consists of sensors (implanted or wearable) and a gateway node. The gateway node in the figure is called Personnel Control Unit (PCU), although other terminologies such as Body Control Unit (BCU) or Central Control Unit (CCU) may be used as well. The function of this gateway node is to collect data from the sensors and forward the data to the medical team through a range of communication networks, such as Wifi and Bluetooth, as well as to act as superior processor for tasks that implantable devices could not handle . This essay will discuss the communication technologies that can be used for the sensors to communicate to this gateway node.
2. Selecting Communication Technologies for Implantable Sensors
As mentioned earlier, communication of sensors to the outside world should be done wirelessly. For medical application, the data transfer system should have low power usage to avoid heating tissue, low bit-error-rate for reliable data transfer, and small in size and light in weight .
In this section, several types of wireless technologies for the implantable sensors communication are explored. Table 1 shows several popular wireless technologies used for medical applications compiled by Texas Instruments/Arrow NAC , but not all of those listed in the table are actually really suitable for implantable sensors application.
Table 2.1 Existing wireless technology standards. Table taken from