Electronics & Communication Engineering Department
Kanyapur, Sen Raleigh
Road, Asansol 713304, Burdwan, India
telecom and computing industries is the basic reason behind the concept
of the Bluetooth. Wireless connections between devices like mobile
phones, desktop or notebook computers thatís without any cable are
made possible with the concept of Bluetooth. Devices which carry
Bluetooth enabled chips, can transfer data at a pace of 720 Kbps within
50 meters(150 feet) of range or even beyond through walls, clothing and
even luggage bags or thin sheets as such.
Bluetooth radio system which is built into a small microchip
operates in a frequency band available globally. This ensures
worldwide interoperability. A collection and combination of several
protocols is what constitutes a Bluetooth protocol. Most of the
The Bluetooth Core
The Bluetooth radio protocols
BLUETOOTH PROTOCOL STACK
protocol stack is a combination of multiple application specific stacks.
Several applications run over many vertical layers from this stack. The
Bluetooth protocol stack is partitioned into layers according to their
functions. These are described as follows:
Base band: The physical RF link between
Bluetooth units forming a piconet is enabled by the Baseband and the
Link Control layer. The transmission with different Bluetooth devices is
synchronized using inquiry and paging procedures. This layer enables
Link Manager Protocol (LMP): LMP indulges itself in message
exchange when two Bluetooth devices come within each othersís radio
range. Each device possess a link manager which then discovers each
other and the LMP does itís task. These messages can perform several
security functions like encryption, authentication etc. LMP also
performs several other functions like:
The LMP controls the power
Duty cycles of Bluetooth
devices are controlled
The connection state is
also controlled by LMP
Logical Link Control and Adaptation
Protocol (L2CAP): The segmentation of large
packets and the reassembly of the corresponding fragmented packets is
done in this layer. Multiplexing of Bluetooth packets from different
applications also takes place in this layer.
Service Discovery Protocol (SDP): A Bluetooth device is enabled
to join a piconet using SDP. This protocol helps a device inquire about
the services available in a piconet and methodologies of accessing them.
Cable Replacement Protocol: This protocol helps in Radio
Frequency Communication (RFCOMM) which is a serial line communication
protocol.The ďcablereplacementĒ protocol emulates RS-232 control
and data signals over Bluetooth baseband protocol.
Telephony Control Specification
Binary: This is a bit- oriented
protocol. It helps in defining the call control signaling protocol
which is used for:
∑ set up of speech between
∑ data calls between
protocol defines commands by means of which mobile phones can be
used and controlled for fax and data transfer.
TCP/IP: This protocol is mainly used
for communication through Internet. TCP/IP finds use in printers and
mobile handsets also.
PPP: Point to point connections is
mainly accomplished by PPP which is over RFCOMM.
Obex Protocol: This is a session protocol
mainly established to exchange objects.
Content Formats: The format of electronic
business card and personal calendar entries developed by the Versit
consortium is defined by the specifications of vCard and vCalendar.