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1
Bluetooth History
The developers of this wireless technology first used the name
"Bluetooth" as a code name, but as time past, the name stuck.
The word "Bluetooth" is taken from the 10th century Danish
King Harald Bluetooth. King Bluetooth had been influential in
uniting Scandinavian Europe during an era when the region
was torn apart by wars and feuding clans.
The founders of the Bluetooth SIG felt the name was fitting
because:
- Bluetooth technology was first developed in Scandinavia,
and
2 ) Bluetooth technology is able to unite differing industries
such as the cell phone, computing, and automotive markets.
Bluetooth wireless technology simplifies and combines multiple
forms of wireless communication into a single, secure, low-
power, low-cost, globally available radio frequency.
Invented in 1994 by L. M. Ericsson, Sweden
Named after Harald Blaatand “Bluetooth”, king of Denmark
940-981 A.D.
Bluetooth SIG founded by Ericsson, IBM, Intel, Nokia and
Toshiba in Feb 1998
More than 1900 members today
2
What is Bluetooth
Bluetooth is a universal radio interface, operates on 79
channels in the 2.4 GHz frequency band with 1 Mhz carrier
spacing that enables electronic devices to connect and
communicate wirelessly via short-range (10-100 m), ad-hoc
networks.
Key Features :
Peak data rate : 1 Mbps ,Low power consumption ,Low cost
(Components (radios and chips) and device adapters are
cheaper).
Affordable and appropriate technology.
Younger technology and therefore is less mature.
Ability to simultaneously handle both voice and data
Line of sight not required
connection of peripheral devices (loudspeaker, joystick,
headset )
support of ad-hoc networking (small devices, low-cost )
bridging of networks (e.g., GSM via mobile phone - Bluetooth –
laptop )
Simple, cheap, replacement of IrDA, low range, lower data
rates( 2.4 GHz, FHSS, TDD, CDMA)
Piconet is a collection of Bluetooth devices which are
System Challenges
Work across a diverse set of devices with
varying computing power and memory
Dynamic environment - the number,
location and variety of devices changing -
connection establishment, routing and
service discovery protocols have to take
this into consideration
Unconscious connection establishment
Size of the implementation should be
small. The power consumption should not
be more than a fraction of the host device.
Piconets , Masters and
Slaves
m s
In principle each unit is a peer with the
same hardware capabilities
Two or more Bluetooth units that share a
channel form a piconet (Bluetooth
Network)
One of the participating units is becomes
the master (by defn the unit that establishes
the piconet).
Participants may change roles if a slave
unit wants to take over as master
Only one master (primary station) in a
piconet. Upto 7 slaves (Secondary station).
The reason for the upper limit of eight
active devices, is the 3-bit address used in
bluetooth
The communication b/w primary and
secondary can be one to one or one-to-many.
Inter-piconet
communication
A unit may participate in more
than one piconet on a TDM basis.
To participate on a piconet it
needs the master’s identity and the
clock offset.
While leaving the piconet it
informs the master.
The master can also multiplex
as slave on another piconet. But all
traffic in its piconet will suspended
in its absence.
