THE LATEST IN NETWORKING AND WIRELESS TECHNOLOGIES
■ BY LOUIS E. FRENZEL W5LEF
TEN THINGS YOU MAY NOT
KNOW ABOUT BLUETOOTH
Making the wireless everywhere
movement come true
BLUETOOTH IS A VERY FAMILIAR NAME THESE DAYS if you have a cell phone or
laptop. It is a wireless technology that has been around a while and probably can
be credited as the start of a whole boat load of short-range wireless technologies.
But even if you have heard the name, you may not really know all about it. Here
are 10 facts that will update your knowledge of this hot wireless method.
10 YEARS OLD
I am not kidding. It was back in
1998 that this wireless method was
conceived by European telecommunications giant Ericsson. Ericsson along
with four other companies selected
the name Bluetooth and formed the
Bluetooth Special Interest Group
(SIG) to develop the technology.
Now it is the most widely used
short-range wireless technology.
BILLIONS SOLD! THERE
ARE MORE BLUETOOTH
RADIOS ON THE PLANET
THAN ANY OTHER
Cambridge Silicon Radio — the
leading Bluetooth chip supplier —
shipped over 600 million chips in
2007 and is expected to ship about
a billion more this year. That’s just
one supplier. The total number of
chips buried in other products is
well over several billion. The reason
76 August 2008
for such high volume is that the
number one use of Bluetooth is to
implement the wireless headset in
cell phones. That means two
Bluetooth chips for each: one in the
handset and the other in the ear
piece. Most cell phones have this
feature today. And since cell phones
sell in the one billion per year range,
you can see how Bluetooth got to
be number one. There are dozens of
other uses, as well. ABI Research —
a market information company —
predicts that about 2.4 billion
Bluetooth-enabled products will
ship in 2013.
THE BLUETOOTH SIG
The Bluetooth SIG is the organization that develops the technology,
establishes the standard, tests for
interoperability and certification, and
promotes the brand. It is a consortium
of over 10,000 companies. And their
work is on-going. For more details on
this wireless success story, go to www.
bluetooth.com or www.bluetooth.org.
AND FEATURES ARE
Bluetooth is a short range technology that operates in the unlicensed
2.4 GHz industrial-scientific-medical
(ISM) band. It has to co-exist with Wi-Fi
LANs, cordless phones, and microwave
ovens, to mention just a few services
that also use this band. But it does pretty
well with a range up to about 30 feet.
The basic output power is 1 m W (0
dBm) but you can use two other
power levels for longer ranges: 2.5
m W ( 4 dBm) and 100 m W ( 20 dBm).
Bluetooth uses a very robust radio
technology called frequency hopping
spread spectrum. It chops up the data
being sent and transmits chunks of it
on up to 75 different frequencies. In its
basic mode, the modulation is Gaussian
frequency shift keying (GFSK). It can
achieve a gross data rate of 1 Mb/s. A
more recent upgrade called Enhanced
Data Rate (EDR) uses π/4-DQPSK
that gives a data rate to 2 Mb/s and
8DPSK that will deliver up to 3 Mb/s.