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What is Bluetooth? Well you can get lots of
different definitions, but essentially Bluetooth is the term used to describe
the protocol of a short range (10 meter) frequency-hopping radio
link between devices. These devices are then termed Bluetooth -
enabled. Documentation on Bluetooth is split into two sections, the Bluetooth
Specification and Bluetooth Profiles.
- The Specification describes how the technology works (i.e
the Bluetooth protocol architecture),
- The Profiles describe how the technology is used (i.e
how different parts of the specification can be used to fulfil a desired
function for a Bluetooth device)
The Specification
is examined first, then the Profiles.
Click on a section of the diagram* above, for a tutorial
of its functions
In more detail: Bluetooth is the
name given to a new technology using short-range radio links, intended to
replace the cable(s) connecting portable and/or fixed electronic devices. It
is envisaged that it will allow for the replacement of the many propriety
cables that connect one device to another with one universal radio link. Its
key features are robustness, low complexity, low power and low cost. Designed
to operate in noisy frequency environments, the Bluetooth radio uses a fast
acknowledgement and frequency hopping scheme to make the link robust.
Bluetooth radio modules operate in the unlicensed ISM band at 2.4GHz, and
avoid interference from other signals by hopping to a new frequency after
transmitting or receiving a packet. Compared with other systems in the same
frequency band, the Bluetooth radio hops faster and uses shorter packets. The
following pages give more detail about different sections of the protocol,
note this tutorial is completely up to date with the latest version of the
bluetooth Specification (ver 1.1)
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| 1 |
Radio |
v1.1 |
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The Radio layer
defines the requirements for a Bluetooth transceiver operating in the 2.4
GHz ISM band. |
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| 2 |
Baseband |
v1.1 |
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The Baseband layer
describes the specification of the Bluetooth Link Controller (LC) which
carries out the baseband protocols and other low-level link routines. |
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| 3 |
LMP |
v1.1 |
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The Link Manager Protocol
(LMP) is used by the Link Managers (on either side) for link
set-up and control. |
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| 4 |
HCI |
v1.1 |
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The Host Controller Interface
(HCI) provides a command interface to the Baseband Link Controller
and Link Manager, and access to hardware status and control registers. |
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| 5 |
L2CAP |
v1.1 |
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Logical Link Control and
Adaptation Protocol (L2CAP) supports higher level protocol
multiplexing, packet segmentation and reassembly, and the conveying of
quality of service information. |
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| 6 |
RFCOMM |
v1.1 |
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The RFCOMM
protocol provides emulation of serial ports over the L2CAP
protocol. The protocol is based on the ETSI standard TS 07.10. |
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| 7 |
SDP |
v1.1 |
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The Service Discovery
Protocol (SDP) provides a means for applications to discover which
services are provided by or available through a Bluetooth device. It also
allows applications to determine the characteristics of those available
services. |
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