Near field Magnetic Induction Communication in Body Area Network Nithya Thilak and Prof. Robin Braun University of Technology Sydney, Australia
[email protected],
[email protected] Abstract
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Next generation wireless communication system may be
NFMIC significance
near filed magnetic induction Communication (NFMIC) which has major application in Body Area Network (BAN). Communication takes place in and around the body is called BAN. This Paper
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Lower Transmission Power since it uses only short distance for communication.
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Low cost system design allows more efficient use of power and bandwidth than conventional RF solution.
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It doesn't operates at busy 2.4SGHz Bandwidth(13.SMHz)
describes the working principle, power equation, its significance and application in NFMIC. It is compared with the other short range wireless technology such as B1uetooth, WLAN, UWB, ZigBee and RFID inside a BAN. This provides information how NFMIC is going to be next generation wireless communication.
I.
BACKGROUND
Wireless communication networks are generally implemented and administered using a transmission system called radio waves [1]. This implementation takes place at the physical level of the network structure. We can classify wireless communications as two types of Short and long range communications. Examples of short range communications are PAN, BAN and long range communication are LAN, WAN and MAN. BAN is subset of PAN. PAN can be used as a gateway for further communications. The various technologies that are used for communication in a BAN are Bluetooth, wireless local area network (WLAN), Ultra Wide Band (UWB), ZigBee, Radio Frequency Identification (RFID) and NFMIC. Bluetooth is a proprietary open wireless technology standard for exchanging data over short range. WLAN links two or more devices over a short distance using a wireless distribution method, usually providing a connection through an access point that also routes information into the Internet [2]. RFID uses radio waves to transfer data from an electronic tag, called RFID tag or label, attached to an object, through a reader for the purpose of identifying and tracking the object. UWB is a radio technology that can be used at very low energy levels for short range high bandwidth communications by using large portion of the radio spectrum. ZigBee is a specification for a suite of high level communication protocols using small, low power digital radios based on IEEE 802 standard for PAN. NFMIC is a short range wireless communication for use up to Sm. It uses magnetic flux for data communication. Information is transferred through the coupling of magnetic field rather than radiation of electromagnetic waves.
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Better Frequency reuse.
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It creates the 3 dimensional 'bubble' that envelops the personal space for each user, which is inherently private and secure.
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It is more reliable in terms of quality of services and robustness
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The only parameter that can affect the transmitted signal is the permeability of the material within the channel.
This technology has been used in many application such as Payment card, Personal area network, MP3 Player, Mobile Player, Wireless power transfer, Biomedical Monitoring, Body implants, Machine to machine communication, under water or ground application, RFID[3] , health monitoring and real time location[4,S]. II. CURRENT RESULT Near field communication versus inductive coupling allows the device to communicate through the coupling of magnetic field rather than the energy radiation/interception process in far field communication. To derive the guidelines on how to evaluate the performance of near field communication links, a near field propagation equation is proposed in [6] which is analogous to Friis's transmission law for far field communication. The block diagram of one near field communication system based on inductive coupling is shown in figure (1)
Tx
rO'X 0=1 ----I
Rx
I
Figure I: Near field communication based on inductive coupling
The communication link is established through the magnetic inductive coupling between the coils of the transmitter and the receiver. The coupling co-efficient is used to qualitatively predict the coupling of the two coils given by [6]: k=
M
�LIL2
The equation 3 shows that the received power is proportional to the quality factors and efficiency of the transmitter and receiver as well as the square of coupling coefficient between the transmitter and receiver. The higher Q gives the higher received power because higher Q means the stronger near field distribution and more power is coupled to the received. Also the received power is totally independent of the radiation impedance of the antenna.
(1) III.
Where M is the mutual inductance and 1., ,L2 is the inductance of the coils of the transmitter and receiver. For two parallel coils centered on a single axis with r2 ::; r1 the coupling coefficient can be approximated as [12].
CONCULSION
Compared to other wireless technology NFMIC is more secure as it uses bubble space around the user. The user can increase or decrease the size of the bubble according to her application, it is not harmful to human body, and sufficient data rate is available. It has major application in the medical field, and further research may be required to minimize interference with other medical devices.
(2) REFERENCES [I]
Overview
of
Wireless
Communications".
cambridge.org.
http://www.cambridge.org/us/catalogue/catalogue.asp?isbn=0521837162 &ss=exc. Retrieved 2008-02-08.
The equivalent circuit model of the system is shown in fig 2. RLpRL2 are the resistances of the coils, and C1,C2, are the
capacitors to form the resonance with the transmitter and receiver's coils in order to have the maximum coupling sensitivity.
', '
R,
l � c � r' A
,. ,o
