Understanding The Magic of Bluetooth Technology
by: Jon Arnold
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Bluetooth technology is a low-power, low-cost wireless technology
for short-range radio communication between various fixed and/or
portable electronic devices such as mobile phones, laptops, PDAs,
cars, stereo headsets, MP3s, digital cameras, PCs and computer
peripherals. Bluetooth also refers to the standard communication
protocol (IEEE 802.15.1) specifically designed for this kind of
short-range wireless communication.
The core of Bluetooth technology lies in a low-cost 9 mm x 9 mm
microchip that functions as a short-range radio link when inserted
into an electronic device, making the device Bluetooth-enabled.
Wireless communication between various bluetooth-enabled devices
takes place via these radio links, instead of via cables as used in
normal networking. Since Bluetooth technology uses radio signals,
which are omni-directional and can be transmitted through walls and
other obstacles, Bluetooth-enabled devices don’t need to be in line
of sight or be pointing at each other.
Bluetooth radio modules operate in the open, unlicensed ISM
(industrial–scientific–medical) spread-spectrum 2.4 GHz frequency
band, divided into 79 channels separated by 1 MHz each. To avoid
interference from other signals, the Bluetooth signal hops to a new
channel every time it transmits or receives a data packet, making
Bluetooth connection robust and secure. The communication range of
Bluetooth technology varies from 1 m to 100 m, depending upon the
maximum power permitted (1 mW to 100 mW). Because of this channel
hopping, there should not be a consistent problem with other devices
using the 2.4 Ghz frequency band, such as old cordless phones.
Each Bluetooth-enabled device can simultaneously communicate with up
to seven other devices within a single personal area network, called
a piconet. Each device can simultaneously belong to several piconets.
Each device negotiates with each other via a defined device name so
that each device can keep track of who it is communicating with. The
device name to use when you are setting up your Bluetooth device is
typically cleared stated in the accompanying device documentation.
Bluetooth technology offers built-in security with 128-bit
encryption and PIN code authentication. When Bluetooth products
identify themselves, they use the PIN code the first time they
connect, thereafter staying securely connected.
Practical Applications of Bluetooth Networking
Some of the popular applications of Bluetooth technology are in
wireless networking between a mobile phone and a laptop/desktop,
between a mobile phone and a hands-free headset, between PCs in a
restricted space and between the input and output devices of a PC
(e.g., mouse, keyboard, printer). Bluetooth technology can also be
used to transfer files, images and MP3 files between mobile phones
or between MP3 players/digital cameras and computers.
Limitations of Bluetooth Technology
Short communication range (up to 100 m) is the greatest limitation
of Bluetooth technology. Also, the data transfer rates are much
lower compared to other wireless communication technologies.
Susceptibility to interference from other devices operating in the
2.4 MHz band, notwithstanding adaptive frequency hopping, is another
limitation. The Bluetooth technology is still not fully developed,
so there is plenty of room for improvement.
Bluetooth-Enabled Devices
The Bluetooth wireless technology specification is available
free-of-charge to Bluetooth member companies around the world. Many
companies are interested in making their devices Bluetooth-enabled
in order to avoid the clutter of wires with seamless connections and
offer simultaneous transmission of data and voice as in hands-free
talking.
Bluetooth technology is commercially available in a wide range of
applications such as mobile phones, automobiles, medical devices,
play stations and many more.
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