10-02-2012, 04:58 PM
Bluetooth Based Smart Sensor Networks
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INTRODUCTION
Bluetooth is wireless high speed data transfer technology over a short range (10 - 100 meters).
Bluetooth Wireless Technology (BWT) was developed in 1994 at Ericsson in Sweden.
Purpose – Originally it was build to eliminate the need for cable connections between PDAs and notebook PCs.
Later the goals were to enable different devices through a commonly accepted standard for wireless connectivity.
BLUETOOTH
Bluetooth Specifications are:
Developed by: Jaap Haarsten and Sven Mattisson in Sweden
Standard: IEEE 802.15
ISM Band Frequency: 2.4 GHz
Range: 10 – 100 meters
Channel Bandwidth: 1 Mbps
Maximum Asymmetric Data Transfer Rate: 721 Kbps
BLUETOOTH TOPOLOGY
Depending on the type of connections established between various Bluetooth devices, 2 main topologies are as:-
PICONET TOPOLOGY, and
SCATTERNET TOPOLOGY
To any topology, there are 2 prime components:-
MASTER device
SLAVE device
PICONET TOPOLOGY
In Bluetooth, each piconet has 1 Master for establishment of piconet, and upto 7 Slave devices.
Master’s Bluetooth address is used for defining frequency-hopping sequence.
Slave devices use master clock to synchronize their clocks so as to hop simultaneously.
For establishing piconet connection, other bluetooth devices in range are discovered by an inquiry procedure.