BLUETOOTH™ 
Overview
The Bluetooth wireless technology
is set to revolutionize the personal connectivity market by
providing freedom from wired connections. It is a specification for
a small form-factor, low-cost radio solution providing links between
mobile computers, mobile phones and other portable handheld devices,
and connectivity to the internet. The Bluetooth Special Interest
Group (SIG), comprised of leaders in the telecommunications,
computing, and network industries, is driving development of the
technology and bringing it to market. The Bluetooth SIG includes
promoter companies 3Com, Ericsson, IBM, Intel, Lucent, Microsoft,
Motorola, Nokia and Toshiba, and thousands of adopter
companies.
Technology
Bluetooth is a global de facto
standard for wireless connectivity. Based on a low-cost, short-range
radio link, Bluetooth cuts the cords that used to tie up digital
devices.
When two Bluetooth equipped devices come within 10
meters range of each other, they can establish a connection
together. And because Bluetooth utilizes a radio-based link, it
doesn't require a line-of-sight connection in order to communicate.
Your laptop could send information to a printer in the next room, or
your microwave could send a message to your mobile phone telling you
that your meal is ready.
 In the future, Bluetooth is likely to be standard
in tens of millions of mobile phones, PCs, laptops and a whole range
of other electronic devices. As a result, the market is going to
demand new innovative applications, value-added services, end-to-end
solutions and much more. The possibilities opened up really are
limitless, and because the radio frequency used is globally
available, Bluetooth can offer fast and secure access to wireless
connectivity all over the world. With potential like that, it's no
wonder that Bluetooth is set to become the fastest adopted
technology in history.
Bluetooth wireless technology is a
system solution comprising hardware, software and interoperability
requirements. The Bluetooth specifications specify the complete
system.
The Bluetooth Specification defines a short (around 10 m)
or optionally a medium range (around 100 m) radio link capable of
voice or data transmission up to a maximum capacity of 720 Kb/s per
channel.
 Radio frequency operation is in the unlicensed
industrial, scientific and medical (ISM) band at 2.4 to 2.48 GHz,
using a spread spectrum, frequency hopping, full-duplex signal at up
to 1600 hops/sec. The signal hops among 79 frequencies at 1 MHz
intervals to give a high degree of interference immunity. RF output
is specified as 0 dBm (1 mW) in the 10m-range version and -30 to +20
dBm (100 mW) in the longer range version.
When producing the
radio specification, high emphasis was put on making a design
enabling single-chip implementation in CMOS circuits, thereby
reducing cost, power consumption and the chip size required for
implementation in mobile devices.
The Bluetooth Solution
answers the need for short-range wireless connectivity within three
areas:
Data
and Voice access points
Cable
replacement
Ad
hoc networking
Data and Voice access
points
Bluetooth wireless technology facilitates
real-time voice and data transmissions, which makes it possible to
connect any portable and stationary communication device as easily
as switching on the lights.
You can, for instance, surf the
Internet and send e-mails on your portable PC or notebook regardless
of whether you are wirelessly connected through a mobile phone or
through a wire-bound connection (PSTN, ISDN, LAN, xDSL).
 Voice
Up
to three simultaneous synchronous voice channels are used, or a
channel which simultaneously supports asynchronous data and
synchronous voice. Each voice channel supports a 64 kb/s synchronous
(voice) channel in each direction.
Data
The
asynchronous data channel can support maximal 723.2 kb/s asymmetric
(and still up to 57.6 kb/s in the return direction), or 433.9 kb/s
symmetric.
-
a Master can share an asynchronous channel with up to 7
simultaneously active Slaves in a Piconet.
-
by swapping active and parked slaves out respectively in the
piconet, 255 slaves can be virtually connected using the PM_ADDR
(a device can participate again within 2 ms).
-
to park even more slaves the BD_ADDR can be used. There is no
limitation to the number of slaves that can be parked.
Slaves can participate in different piconets and a master
of one piconet can be the slave in another, this is known as a
scatternet. Up to 10 piconets within range can form a scatternet,
with a minimum of collisions.
Cable
replacement
Bluetooth wireless technology eliminates
the need for numerous, often proprietary, cable attachments for
connection of practically any kind of communication device.
Connections
are instant and they are maintained even when devices are not within
line of sight. The range of each radio is approximately 10 meters,
but it can be extended to around 100 meters with an optional
amplifier.
Ad hoc
networking
A device equipped with a Bluetooth radio
establishes instant connection to another Bluetooth radio as soon as
it comes into range.
Since each Bluetooth device supports both
point-to-point and point-to-multipoint connections, several piconets
can be established and linked together ad hoc. The Bluetooth
topology is best described as a multiple piconet structure.
Products
Many companies have
declared that Bluetooth wireless technology will be incorporated
into their products, especially when components becomes cheaper. In
a forecast made by Cahners In-Stat Group (July 2000), the product
availability during the next couple of years was defined as three
waves.
The first wave is believed to occur around the turn of
the year 2000/2001 and will include products like:
-
Adapters for mobile phones and adapters (dongles) and PC Cards
for notebooks and PCs.
-
High-end mobile phones and notebook PCs with integrated
Bluetooth communication for the business users.
-
Bluetooth headsets are expected to enter the market by the
first half of 2001.
-
Cordless phones, handheld PCs, and PDAs will also be included
in this first wave. The first handheld PCs and PDAs are expected
to enter the market during 2001.
The second wave will in
many respects overlap the first. What we will see here is:
-
PCs with Bluetooth circuitry on the motherboard.
-
Printers, fax machines, digital still cameras, and products
for industrial/medical and vertical industries will also begin to
move in the second wave.
-
Some industrial solutions may become available as soon as the
end of 2000 or 1Q2001.
-
In the automotive sector the first Bluetooth options are
expected to appear for the 2002 model year
(hands-free mobile
phone usage with your regular mobile phone).
The third
wave will include:
Competing Technologies
There is no single
competitor covering the entire concept of the Bluetooth wireless
technology but in certain market segments other technologies exist.
For
cable replacement the infrared standard IrDA has been around for
some years and is quite well known and widespread. IrDA is faster
than the Bluetooth wireless technology but is limited to
point-to-point connections and above all it requires a clear
line-of-sight. In the past IrDA has had problems with incompatible
standard implementations, a lesson that the Bluetooth SIG has
learnt.
Two other short-range radio technologies using
frequency hopping technique reside in the 2.4 GHz band:
Wireless
LANs based on the IEEE 802.11 standard. The technology is used to
replace a wired LAN throughout a building. The transmission capacity
is high and so is the number of simultaneous users. On the other
hand, compared to Bluetooth wireless technology, it is more
expensive and power consuming, and the hardware requires more space.
It is therefore not suitable for small mobile devices.
The
other 2.4 GHz radio is Home RF, which has many similarities to the
Bluetooth wireless technology. Home RF can operate ad hoc networks
(data only) or be under the control of a connection point
coordinating the system and providing a gateway to the telephone
network (data & voice). The hop frequency is 8 Hz while a
Bluetooth link hops at 1600 Hz.
Ultra-Wideband Radio (UWB) is
a new radio technology still under development. Short pulses are
transmitted in a broad frequency range. The capacity appears to be
high while power consumption is expected to be low.
BLUETOOTH™
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