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ABSTRACT
Bluetooth technology is a wireless replacement for many of the cables we currently use to transmit
voice signals and data signals. It is the result of joint achievements of nine leading companies:
3COM, Lucent Technologies, IBM, Intel, Microsoft, Motorola, Nokia, Toshiba, Sony Ericsson,
altogether known as the Bluetooth Special Interest Group. The idea is to create a single wireless
protocol to address the end-user problems arising from proliferation of mobile devices and PCs.
The Bluetooth specification is ideal for mobile professionals who need to link notebook computers,
mobile phones, laptops, digital cameras, speakers, and other hand-held devices to do business at
home, on the road, or in the offices. Governments worldwide control it, so it is possible to utilize
the same standard wherever one moves. Bluetooth provides three low power modes to conserve
battery life: (sniff mode, hold mode, and park mode). It aims at low power consumption and
provides security for both stationary and mobile devices.
A Bluetooth chip (usually 9mm x 9mm) takes the information normally carried by the cables, and
transmits it at a special frequency to a receiver end.
Bluetooth is a standard that allows any kind of electronic equipment or device –from cellphones
to keyboards and headphones-to make its own connections without direct action from a user end.
Bluetooth is emerging as the short-range connection media of choice amongst mobile devices and
electronic equipment, giving the user, ease of operation.
Introduction:
A look around at the instance! Keyboard connected to the computer, as well as a printer, mouse,
monitor and so on. What (literally) joins all of these together? They are connected by cables.
Cables have become the bane of many offices, homes etc. That is what the Bluetooth technology
aims at – a cable replacement technology!
Bluetooth:
One of the most significant recent developments in wireless technologies is the emergence of
Wireless personal area networking (WPAN) or Wireless local area networking (WLAN). We
further discuss WPAN. WPAN is based on a technology called Bluetooth which uses short-range
radio frequencies to transmit both voice and data signals. The bluetooth technology wirelessly and
transparently synchronize data across devices and creates access to networks and the Internet
within a range of few meters. The short-range networks Bluetooth enables are called Personal Area
Networks (PANs). Bluetooth is able to move from frequency to frequency, making it much better
able to handle interference than other competing protocols. Bluetooth technology is the result of
the joint achievements of nine leading companies: 3com, lucent technologies, IBM, Intel,
Microsoft, Motorola, Nokia, Toshiba, Ericsson altogether known as the Blue Tooth Special
Interest Group (SIG), which has widespread participation by many companies. Originally initiated
by L M Ericsson. It was designed as a short-range communications medium for wireless headsets
to communicate and connect with mobile phones.
Features:
It separates the frequency band into hops. This spread spectrum is used to hop from one
channel to another, which adds a strong layer of security between connected devices.
Signals can be transmitted through walls and briefcases, thus eliminating the need for lineof-sight.
Devices do not need to be pointed at each other, as signals are omni-directional.
Both synchronous and asynchronous applications are supported, making it easy to
implement on a variety of devices and for a variety of services, such as voice and Internet.
Governments all over the world controls it, so it is possible to utilize the same standards
wherever one travels in the World.
It is to arrive at a specification for a technology that optimizes the usage model of all mobile
computing and communications devices, and providing:
o Voice and data signals handling.
o The ability to create Ad-Hoc Connections.
o Very small in size, In order to install it into variety of devices with very small power
consumption as compared to other devices for similar use.
o An open interface standard and competitively low cost of all units, as compared to
their non-Bluetooth correspondent devices.
BLUETOOTH is used in Phones and Headsets, Modems and LAN access devices, Notebook
computers, laptops, Desktop and handheld computers, Printers and Fax machines, Keyboards and
Joystick, and Mouse etc.
Specification:
Bluetooth is a worldwide specification for a small form-factor, low-cost radio stations providing
links b/w computers, mobile phones, and other devices. The Institute of Electrical and Electronics
Engineers (IEEE) has given the IEEE 802.15 standard. Time-Division Duplex (TDD) scheme is
used for full-duplex transmission of data. Its main strength is its ability to simultaneously handle
both data and voice signals transmissions. A mobile computer equipped with Bluetooth
technology, for example, could link to a similarly equipped phone to connect to the Internet.
Multiple Bluetooth units form a Wireless Personal Area Network with seven client devices. A
Bluetooth WPAN is capable of supporting an asynchronous data link with each client and
synchronous voice links with up to three client devices. It provides a range of up to 10 meters at a
transmit power of 1 mwatt. The range can be extended to 100 meters if the transmit power is
increased to 100 mwatt. Bluetooth has a data rate of 1 Mbps. Bluetooth is a standard for a small
(9mm x 9mm) , cheap radio chip to be plugged into computers, printers, mobile phones, and other
devices. A Bluetooth chip takes the information normally carried by the cable, and transmits it at
a special frequency to a receiver. Bluetooth chip, which will then give the information received to
the computer, phone whatever. Bluetooth offers the most economical solution for low-to-medium
speed device connectivity. It aims at low power consumption and provides security for both
stationary and moving/mobile devices.
Technical standards and performance levels
1. Bluetooth is based upon a small, very high performance integrated radio transceivers,
each of which is allocated a unique 48-bit address derived from the IEEE 802 standards.
2. It operates in the unrestricted 2.45 GHz ISM ’free band’, which is available globally,
although slight variation of location and bandwidth applied.
3. The range is set at 10 meters to optimize for target market of mobile and business user.
The range can be increased up to 100 meters.
4. Transmission data rate is 1Mb/s, with second generation plans to increase to 2 Mb/s.
One-to-one connections allow maximum data transfer rate of 721 kb/s.
5. Bluetooth uses a packet switching protocols, based on a frequency hop scheme with
1600 hops/s. To enable high performance in noisy radio environments. The entire available
frequency spectrum is used with 79 hops of 1 M hertz bandwidth, according to the IEEE 802.11
standard.
6. It has low power consumption, drawing only 0.3 mA in standby mode. This enables
maximum performance for battery powered devices. During data transfer the maximum current
drain is 30 mA. However, during pauses or at lower data rates the drain would be much lower.
Bluetooth Network Topology:
There are 3 types of connections in Bluetooth.
I. Single-slave
II. Multi-slave (up to 7”slaves”on one master)
III. Scatternet. Multiple Bluetooth units form a Wireless Personal Area Network, called a
piconet. A piconet consists of one hub device and up to seven client devices.
A piconet can be created in one of 4 ways:
A page (used by Master to connect to Slave)
A page scan (a unit listens for its´ device access code)
A Master – Slave switch is made
An ”Unpark” of a unit is made (provided there are no active slaves).
Personal Networking Hardware And the Protocol Stack Layers:
Bluetooth radio modules use Gaussian Frequency Shift Keying (GFSK) for modulation. The data
is transmitted at a data rate of 1 Mb/second.
o The Bluetooth Baseband Layer:
The baseband layer performs functions like Bluetooth packet assembly, forward error
correction (FEC), automatic repeat request (ARQ), data whitening, Bluetooth clock
synchronization, and frequency hopping control etc.
o The Bluetooth Link Manager Layer:
The Link Manager forms the piconet by inquiring what other Bluetooth radios are in the area,
establishing connection and maintaining the piconet. The Link Manager also handles security
issues like authentication and encryption.
o Radio:
The Radio layer defines the requirements for a Bluetooth transceiver operating in the 2.4 GHz
ISM band.
Base band:
This layer describes the specification of the Bluetooth Link Controller (LC) which carriesout
the baseband protocols and other low-level link routines.The Link Manager Protocol (LMP) is
used by the Link Managers (on either side) for link set-up and control.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.
o Logical Link Control and Adaptation Protocol (L2CAP)
It supports higher level protocol multiplexing, packet segmentation and reassembly, and the
conveying of quality of service information.L2CAP, which adapts upper layer protocols over
the Baseband, provides data services to the high layer protocols with group abstractions. The
RFCOMM protocol provides emulation of serial ports over the L2CAP protocol. The protocol
is based on the ETSI standard TS 07.10. The Service Discovery Protocol (SDP) provides a
means for applications to discover which services are provided by or available through a
Bluetooth device. Device information, services and the characteristics of the services can be
queried using the SDP.
The Power Modes:
Bluetooth provides for three low power modes to conserve more battery life: sniff mode, hold
mode, and park mode.
In the sniff mode, a device listens to the piconet at a reduced rate. The sniff interval is
programmable, providing flexibility for different applications.
In hold mode, only an internal timer is running, and data transfer restarts when units transition out
of the hold mode.
Park mode is used to handle more than seven clients - since only seven clients can be “active” at
any time, one client can be “parked” and another one is activated.
The advantage of “frequency-hopping”
Bluetooth has been designed to operate in noisy radio frequency environments, and uses a fast
frequency-hopping scheme to make the link robust, communication-wise. Bluetooth radio modules
avoid interference from other signals by hopping to a new frequency after transmitting or receiving
a packet.
Compared with other systems operating
In the same frequency band, the Bluetooth radio typically hops faster and uses shorter packets.
This is because short packages and fast hopping limit the impact of microwave ovens and other
sources of disturbances. Use of Forward Error Correction (FEC) limits the impact of random noise
on long-distance links. Bluetooth can support an asynchronous data channel, or up to 3
simultaneous synchronous voice channels, or a channel which simultaneously supports
asynchronous data and synchronous voice.
Safer transmission of data:
Bluetooth has built insufficient encryption and authentication and is thus very secure in any
environment. In addition to this, a frequency-hopping scheme with 1600 hops/sec. is employed.
This is far quicker than any other competing system. This, together with an automatic output power
adaption to reduce the range exactly to requirement, makes the system extremely difficult to
eavesdrop. The transmitting power is far too weak to be noticeable for humans.
Moreover, the radiation is not concentrated in a beam, but dispersed more or less in all directions.
Hence not dangerous!!
In Bluetooth, it has these components: Random Numbers Generation, Encryption Key
Management and Authentication.
Examples:
1. A Bluetooth-mouse or a Bluetooth-keyboard could be used at a further distance from a
monitor, and while moving about in the room with in the range.
2. Use e-mail while your portable PC is still in the briefcase! When your portable PC
receives an e-mail, you'll get an alert on your mobile phone.
3. A travelling businessman could ask his laptop computer to locate a suitable printer as
soon as he enters a hotel lobby, and send a printout to 0074hat printer when it has been found, and
replied in a positive manner.
4. Cable-less connection to printers and faxes, to digital cameras and video projectors.
Cordless connection from cell phone to handsfree headset.
5. Bluetooth interface to office PBX and Dial-up networking and automatic e-mail and use
cell phone as office cordless phone. Use of PC or PDA as handsfree phone.
6. Automatic exchange of files, electronic business cards, calendars etc.
Conclusion:
Despite some of the problems, Bluetooth remains a very promising technology, with plenty of
medium and long term applications. But the real test will be whether it survives the hype.
Promoters are laying on it, with their unrealistic claims.
This technology is probably the only one which has a good chance to become widely available
among PDAs and mobile devices. Bluetooth-equipped gadgets can connect to the LAN through
the Access Protocols at once.50 kilobytes per second is about all you can expect from Bluetooth.