Ø Bluetooth
is a proprietary open wireless technology standard for exchanging data over
short distances (using short-wavelength radio transmissions in the ISM band
from 2400–2480 MHz) from fixed and mobile devices, creating personal area
networks (PANs) with high levels of security.
Created by telecoms vendor
Ericsson in 1994, it was originally conceived as a wireless alternative to
RS-232 data cables. It can connect several devices, overcoming problems of
synchronization.
v Bluetooth
Protocol
Ø Uses
the unlicensed 2.4 GHz ISM (Industrial Scientific and Medical) frequency band.
Ø 79
available channels spaced 1 MHz apart from 2.402 GHz to 2.480 GHz.
Ø Allows
power levels starting from 1 mW (covering 10 centimetres) to 100mW (covering
upto 100 meters) suitable for short device zone to personal area networks
within a home.
Ø Supports
both unicast (point-to-point) and multicast (point-to multipoint) connections.
Ø Bluetooth
protocols are a collection of many inter-related protocols.
Ø Uses
the master and slave relationship.
Ø Master
and slaves together form a Piconet when master allows slaves to talk.
Ø Up
to seven ‘slave’ devices can be set to communicate with a‘master’ in a Piconet.
Ø Scatternet
is formed when several of piconets are linked together to form a larger network
in an ad hoc manner.
Ø Scatternet
is a topology where a device from one piconet also acts as a member of another
piconet wherein a device being a master in one piconet can simultaneously be a
slave in the other one.
