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Abstract:
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As
the technology becomes more sophisticated, the need for facile wireless
communication has led the human brain to renovate the orthodoxy bottlenecked
conventions being used. Computing will inevitably be indispensable and
ubiquitous – a scenario that has no place for wires. Bluetooth provides several
irksome issues that have plagued implementation of wireless technology handling
both data and voice transmissions, allowing such capabilities as a mobile
hands-free head set for voice calls and print-to-fax, laptop and cell phone
address book applications. More than just a replacement for Proprietary cables,
Blue tooth wireless technology provides a Universal bridge to existing data
networks LAN’s, mobile phone network and the internet for a host of home applications
and portable hand-held interfaces.
Bluetooth enabled
electronic devices connect and communicate wirelessly via short-range, ad-hoc
networks called ‘Piconets’. Each unit can simultaneously communicate with up to
seven other units in a piconet. These piconets are established dynamically and
automatically as blue tooth devices enter and leave the radio proximity. To
replace messy wires, make information transfer automatic without
synchronization cradles and introduced many applications Bluetooth excels at
connecting devices irrespective of their locations and can even talk through
walls.
Introduction
What is Bluetooth?
Bluetooth is the global defector
standard for wireless connectivity based on low-cost, short-range radio link
that resides on a micro chip. Bluetooth wireless technology is a system
solution comprising hardware, software and Interoperability requirements. Bluetooth is a standard for a small, cheap
radio chip to be plugged in to computers, printers, mobile phones etc.
Bluetooth wireless technology eliminates the need for numerous, often Proprietary, cable attachments for
connection of practically any kind of communication device.
Concept behind
Bluetooth
The basic concept
behind the Bluetooth is to provide a universal short range wireless capability.
It operates in free Industrial Scientific Medical(ISM) band from 2.400 GHz to
2.483GHz, available globally for unlicensed low-power uses. Two Bluetooth
devices within 10m of each other can share up to 720kbps of capability. It has
the transmission power of 1mW. Bluetooth
is intended to support an open-ended list of applications, including data,
audio, graphics and even video. For e.g. Audio devices can include headsets,
cordless and standard phones, home stereos, and digital MP3 players.
Security
Architecture
When wireless connection is
used in communication the eavestroping is much easier. That’s why security and
encryption is very important with Bluetooth devices. BT specifies security on
several levels from base band to service level. Base band uses SAFER+
algorithms for security purposes. BT’s encryption engine requires master nodes
BT address its slot clock and secret key i.e. that is shared by all the
participant devices.
Architecture overview
The ‘core protocols’ form a five-layer stack
consisting of the following elements:
• Radio: Specifies details of the air
interface, including frequency, the use of frequency hopping, modulation
scheme, and transmit power.
• Baseband: Concerned with connection
establishment within a Pico net, addressing, packet format, timing, and power
control.
• Link manager: responsible for link setup
between Bluetooth devices and on going link management. This includes security
aspects such as authentication and encryption, plus the control and negotiation
of base band packet sizes.
• Logical link control and adaptation
protocol (L2CAP): adapts upper-layer protocols to the base band layer.L2CAP
provides both connectionless and connection-oriented services.
• Services discovery protocol (SDP): is
device information, services, and the characteristics of the services can be
queried to enable the establishment of a connection between two or more
Bluetooth devices.
Network Topology
Bluetooth devices are
generally organized into groups of two to eight devices called Piconets,
consisting of a single master device and one or more slave devices. A device
may additionally belong to more than one piconet, either as a slave in both or
as a master of one piconet and a slave in another. These bridge devices
effectively connect piconets into a scatternet. A diagram of a Bluetooth
scatternet is shown in figure above. Bluetooth operates in the unlicensed ISM
frequency band that is generally cluttered with signals from other
devices-garage door openers, baby monitors, and microwave ovens, to name just a
few. This pattern, moving through 1,600 different frequencies per second, is
unique to the particular piconet. Each frequency “hop” is a time slot during
which data packets are transferred. A packet may actually span up to five time
slots, in which case the frequency remains constant for the duration of that
transfer.
Conclusion
Designed as a cable-replacement
technology, Bluetooth wireless technology is well suited to the connectivity
requirements of WPANs composed of portable computers, PDAs, mobile phones, and
printers. It is ideally suited to mobile devices (particularly PDAs) because of
their small size, low power requirements, and applications (mobile phone
wireless WAN connectivity, peer-to-peer business card or calendar exchange, and
wireless synchronization). As the technology matures, implementations increase,
and native operating system support becomes available, interoperability and
ease-of-use issues should diminish. Industries are committed to provide
Bluetooth solutions that meet customer needs, have been thoroughly tested for
compliance, and coexist with Wi-Fi networks. The possibility for new
applications is very exciting with this versatile technology. The Bluetooth communication device will thus
be a small, low powered radio in a chip that will talk to other Bluetooth
enabled products. Bluetooth has been designed to solve a no. of connectivity
problems experienced by the mobile workers & consumers. Thus, this
technology helps make the electronic devices more user-friendly.
