1. ABSTRACT
Bluetooth is a communication standard for short-distance
wireless communication. It replaces the many proprietary cables that connect
one device to another with a single universal short-range radio link. For
instance Bluetooth radio technology built into both the cellular phone and the
laptop would replace the cable used today, to connect a laptop to a cellular
phone.
Bluetooth radio technology provides a Universal bridge to
existing data networks, a peripheral interface and a mechanism to form small
private ad hoc groupings of connected devices away from fixed network
infrastructures.
The paper about Bluetooth technology provides description of
some of the usage models and explains how the Bluetooth architecture is
optimized to enable them.
This paper concentrates on how the security is implemented in
Bluetooth wireless technology. It also deals with applications and future
developments of the same area as well as how the Bluetooth is positioned
relative to other wireless technology standards.
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2. S.no. Table of Contents Page no.
1.0 INTRODUCTION
1.1 Bluetooth 3
1.2 History of Bluetooth 5
2.0 THEORY
2.1 Bluetooth Topology 6
2.2 Bluetooth Hardware Architecture 9
2.3 Application of Bluetooth 11
3.0 BLUETOOTH ARCHITECTURE 12
3.1 Security 16
3.2 Advantages of Bluetooth 18
3.3 Disadvantages of Bluetooth 18
4.0 BLUETOOTH IN FUTURE 19
5.0 LITERATURE SURVEY 20
6.0 CONCLUSION 23
7.0 REFERENCE 24
1.0 INTRODUCTION
1.1 BLUETOOTH
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3. Bluetooth Technology was first launched in the year 1994. When
launched, it gave a brilliant surprise to portable lifestyle. It was developed to
provide a wireless interconnect between small mobile devices and their
peripherals. This new innovation has given a solution to give cable free computer
connections, which means real freedom to working environment despite location
and wire availability.
Bluetooth wireless allows portable computers, notebooks, mobile
phones, personal digital assistant and other handy gadgets to make use of ‘short
range, low power’ radio technology to connect to each other. Bluetooth technology
gives 400 KBPS data transfer rate and operates in 2.4 GHz frequency band, similar
to cordless phones and 802.11b wireless LAN technology. It also supports 10-m
computers connection at 1 MBPS speed.
Original Bluetooth market requirements dictated integration into small
handheld devices, low cost, high security, low power and ubiquitous global use of
Bluetooth technology. The goals of the technology did not include developing
another wireless Local Area Network (WLAN) technology, for which there was
already many in the market and many more being developed. While WLAN had
good ad hoc networking there was no clear market standard to pick. Moreover cost
was too high for integration, there were no global standards and integration into
small handheld devices was a problem. As such it was decided to take a different
approach: replace the cable from the ‘Network Adapters’ with a low cost RF link
that we now call BLUETOOTH.
Bluetooth has taken its first step as a basic cable replacement
technology and is now quickly evolving into more sophisticated applications such
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4. as peer to peer networking and personal area networking for cellular phones,
PDAs, Computers, Printers and other devices. The market for Bluetooth handsets
is forecast to increase dramatically reaching a total of 779.7 million devices by the
year 2006.
Bluetooth is a global standard for wireless connectivity. Today
Bluetooth technology is the only specification targeted at this new market of cable
replacement. Even the IEEE organization has recognized the need for wireless
cable replacement technology and started the development of the 802.15-working
group that focuses on this market.
The Bluetooth technology tries to emulate the cost, security and
capabilities of common cables carried by mobile travelers. “The technology must
be secure as a cable; must be manufactured for about the same cost as a cable;
must connect to variety of devices available to the mobile users and support data
rates that are consistent with a mobile travelers needs; must support many
simultaneous and private connections, must support the types of data used by the
mobile users and must be very low power and compact to support the small
portable devices into which the technology must be global as the mobile devices
will travel and must work with devices found in other parts of the world”.
1.2 HISTORY OF BLUETOOTH
The idea that resulted in the Bluetooth wireless technology was born in 1994 when
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5. Ericsson decided to investigate the feasibility of a low-power, low-cost radio interface
between mobile phones and their accessories (www.bluetooth.com). The idea was that
a small radio built into both the cellular telephone and the laptop would replace the
cumbersome cable used today to connect the two devices.Today, the Bluetooth wireless
technology is supported by the Bluetooth SIG (Special Interest Group). The main
players in this group include 3Com Corporation, Ericsson Technology Licensing AB,
IBM Corporation, Intel Corporation, Agere Systems, Inc., Microsoft Corporation,
Motorola Inc., Nokia Corporation, and the Toshiba Corporation.In February of 2000,
Bluetooth SIG membership exceeded 1525 companies.The backing and support from
these companies insures that Bluetooth will receive a chance to gain acceptance in today’s
wireless market.
Bluetooth operates in the unlicensed ISM band at 2.4 GHZ frequency band and use
frequency hopping spread spectrum technique. A typical Blue tooth device has a range of
about 10 meters and can be extended to 100meters. Communication channels supports
total bandwidth of 1 Mb / sec. A single connection supports a maximum asymmetric data
transfer rate of 721 KBPS maximum of three channels.
The engineers who designed Bluetooth are: J.Haarsten and S.Mattisson
2.0 THEORY
2.1 BLUETOOTH TOPOLOGY
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6. Depending upon the type of connection established between the various bluetooth
devices,there are two main topologies :
1.PICONET TOPOLOGY
2.SCATTERNET TOPOLOGY
To any topology there are two main devices:
1.Master device
2.Slave device
PICONET TOPOLOGY:
In bluetooth, a Piconet is a collection of up to 8 devices that frequency hop
together. Each Piconet has one master usually a device that initiated establishment
of the Piconet, and up to 7 slave devices. Master’s Blue tooth address is used for
definition of the frequency hopping sequence. Slave devices use the master’s clock
to synchronize their clocks to be able to hop simultaneously.
When a device wants to establish a Piconet it has to perform inquiry to discover
other Blue tooth devices in the range. Inquiry procedure is defined in such a way to
ensure that two devices will after some time, visit the same frequency same time
when that happens, required information is exchanged and devices can use paging
procedure to establish connection.
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7. When more than 7 devices needs to communicate, there are two options.The first
one is to put one or more devices into the park state. Blue tooth defines three low
power modes sniff, hold and park. When a device is in the park mode then it
disassociates from and Piconet, but still maintains timing synchronization with it.
The master of the Piconet periodically broadcasts beacons (Warning) to
invite the slave to rejoin the Piconet or to allow the slave to request to rejoin. The
slave can rejoin the Piconet only if there are less than seven slaves already in the
Piconet.
If not so, the master has to ‘park’ one of the active slaves first. All these actions
cause delay and for some applications it can be unacceptable for eg: process
control applications, that requires immediate response from the commandcentre
(central control room).
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8. SCATTERNET TOPOLOGY:
Scatternet consists of several Piconets connected by devices participating in
multiple Piconet. These devices can be slaves in all Piconets or master in one
Piconet and slave in other Piconets. Using scatternets higher throughput is
available and multi-hop connections between devices in different Piconets are
possible. i.e., The unit can communicate in one Piconet at time so they jump from
pioneer to another depending upon the channel parameter.
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9. 2.2 BLUETOOTH HARDWARE ARCHITECTURE
A blue tooth module consists primarily of three functional blocks – an analog 2.4
GHz., Blue tooth RF transceiver unit, and a support unit for link management and
host controller interface functions.The host controller has a hardware digital signal
processing part- the Link Controller (LC), a CPU core, and it interfaces to the host
environment. The link controller consists of hardware and software parts that
perform blue tooth based band processing, and physical layer protocols. The link
controller performs lowlevel digital-signal processing to establish connections,
assemble or disassemble, packets, control frequency hopping, correct errors and
encrypt data.
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10. The CPU core allows the blue tooth module to handle inquiries and filter page
request without involving the host device. The host controller can be programmed
to answer certain page messages and authenticate remote links. The link
manager(LM) software runs on the CPU core. The LM discovers other remote
LMs and communicates with them via the link manager protocol (LMP) to perform
its service provider role using the services of the underlying LC. The link manager
is a software function that uses the services of the link controller to perform link
setup, authentication, link configuration, and other protocols. Depending on the
implementation, the link controller and link manager functions may not reside in
the same processor.
Another function component is of course, the antenna, which may be integrated on
the PCB or come as a standalone item. A fully implemented bluetooth module also
incorporates higher-level software protocols, which govern the functionality and
interoperability with other modules. Gate way plays the role of the Piconet’s
master in the sensor network.
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11. 2.3 APPLICATION OF BLUETOOTH:
· Consumer Electronics
e.g. Bluetooth headphones, speakers, keyboard, mouse.
· Medical devices
With the help of these divices various data can be collected and can be sent
directly to the computer to keep a daily track of patients heart beat,blood sugar
levels etc.
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12. · Sports devices like GPS,Heartbeat monitor,speedometer etc also use
Bluetooth sensor.
3.0 BLUETOOTH ARCHITECTURE
The Bluetooth technology is divided into two specifications. The
Core and the Profile specifications. The Core specification discusses how the
technology works while the profile specification focuses on how to build
inter operating devices using the core technologies. Here the data
transmission is a series of protocols within the Bluetooth system that
possesses the data for suitable transmission and receipt. A good
representation of General Bluetooth Architecture is provided as
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13. Device 1 Bluetooth System Device 2
Hierarchy
Data Transfers Data Transfers
HCI HCI
Bluetooth
Link
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High level Applications
WAP,UDC/TCP,PPP,IP Connects
to RFCOMM,SDP,TCS Connects
to L2CAP
High level Applications
WAP,UDC/TCP,PPP,IP Connects
to RFCOMM,SDP,TCS Connects
to L2CAP
RFCOMM
Emulates a serial port
and allows transfer of
data and form L2CAP
RFCOMM
Emulates a serial port
and allows transfer of
data and form L2CAP
L2CAP
Perform segmentation,
Reassembly and multiplexing of
high level applications
L2CAP
Perform segmentation,
Reassembly and multiplexing of
high level applications
LINK MANAGER PROTOCOL
AND BASEBAND CONTROLLER
Baseband Controller performs the low
level processing of packet
composition and decomposition. Link
manager handles Link setup and
Control
LINK MANAGER PROTOCOL
AND BASEBAND CONTROLLER
Baseband Controller performs the low
level processing of packet
composition and decomposition. Link
manager handles Link setup and
Control

14. At the highest architecture level lies the different communication
and data information protocols that can communicate over the Bluetooth link,
including Wireless Application Protocol(WAP), User Diagram Protocol
(UDP), Transport Control Protocol(TCP), Internet Protocol(IP), and Point to
Point Protocol(PPP). While all of these are standalone communication
protocols, they can be adapted for transmission over a Bluetooth link. To
support these different types of Communication protocols, the Bluetooth
system architecture must capable of differentiating and converting data
associated with these protocols into data packets that the Bluetooth baseband
controller and RF transceiver can send.
One of the protocols within the Bluetooth architecture that is
responsible for this adaptation is RFCOMM, which emulates a serial port
and can be used by applications that use the serial ports on a Bluetooth
device. RFCOMM can take the data from some of the higher level protocols
mentioned previously and adapt it so it can be sent down to the baseband and
converted into Bluetooth data packets and subsequently sent over a Bluetooth
link.
Below RFCOMM lies the logical link control and adaptation
protocol (L2CAP) that further supports the adaptation of other
communication protocols such as Telephony Control Specification binary
(TCS-binary) and the Bluetooth established Service Discovery Protocols
(SDP) as well as performing the multiplexing between all incoming upper
level protocols (RFCOMM, TCS, SDP).
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15. In addition to protocol multiplexing L2CAP is responsible for the
segmentation of outgoing data packets so they may be transferred to the
baseband processor, since the baseband processor cannot handle data packets
of great size. L2CAP is also responsible for the reassembly of received data
packets, which are subsequently sent to one of the higher level protocols
designated to receive this data.
Once the original data has been segmented by L2CAP into
subsequent L2CAP packets, the packets are then sent to the host controller
interface (HCI), which is responsible for sending data and receiving data
from the lower level Bluetooth hardware (Baseband Controller) through a
physical bus (USB, RS232, PCI). HCI further alters the L2CAP packets so
that the data may be transported over one of the physical buses. The link
manager and baseband controller that assemble it into packets that are
communicating using a Bluetooth link receive this data.
At the lowest level lie the link manager and the baseband
controller. The baseband controller performs all low level processing, such
as Bluetooth packet composition for transmission and packet decomposition
upon reception. Running on the baseband controller is firmware
implementing the link manager protocol, which handles link control is
responsible for placing the device in low power states, and performs any
encryption of data transmitted.
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16. 3.1 SECURITY
The way that the Bluetooth radio system is used in mobile
devices and the type of data carried on these devices makes security an
extremely important factor. While most wireless systems will claim that
being a spread spectrum radio provides security, the volumes projected for
Bluetooth radios eliminate this barrier. The link layer security architecture is
given as
At a link layer, the Bluetooth radio system provides
Authentication, Encryption and Key management of the various keys
involved. Authentication involves the user providing a Personal Identification
Number (PIN) that is translated into a 128-bit link key that can be
authenticated in a one or two way direction. Once the radios are authenticated
the link can be encrypted at various key lengths.
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17. The link layer security architecture provides a number of
authentication schemes and a flexible encryption scheme that allows radios to
negotiate for key length. This is important, as radios from different countries
will be talking to each other. Security policies in these countries will dictate
maximum encryption key lengths. Bluetooth radios will negotiate to the
smallest common key length for the link. The Bluetooth architecture also
supports authorization of different services to upper software stacks. For
example, when two computers have created a Bluetooth link to exchange
business cards, authorization must be created to extend these services.
The Bluetooth security architecture relies on PIN codes for
establishing trusted relationships between devices. While not practical to go
through all the combinations of uses of PIN codes, it should be noted that
once a trusted pairing is established between devices, these codes could be
stored within the device to allow more automatic/ simple connections. The
key to Bluetooth simplicity will be establishing the trusted relationship
between commonly used devices. For random ad hoc connections that require
authenticated connections, PINs would have to be exchanged.
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18. 3.2 Advantages of Bluetooth
1. Eliminates wires and cables between both stationary and mobile devices.
2. Facilitates both data and voice communication
3. Offers the possibility of ad hoc networks and delivers the ultimate
synchronicity between all your personal devices
4. It’s inexpensive.
5. You don't have to think about it, the devices find one another and strike up
conversation without any user input at all.
3.3 Disadvantages of Bluetooth
1. Compatibility between Bluetooth products
2. Security
3. Relatively short range
4.Interference with other devices that may use the same frequency, such as baby
monitors, garage door openers, cordless phones, microwave ovens, and other
wireless technologies which use the same frequency.
5.Mediocre data transfer rate.
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19. 4.0 BLUETOOTH IN THE FUTURE
Future direction of the Bluetooth standard
At this time, we anticipate the Bluetooth SIG to evolve the
Bluetooth technology to provide greater bandwidth & distances, thus
increasing the potential platforms & applications used in the emerging
Personal area networking marketplace.
Future of Bluetooth
Bluetooth is a continually expanding technology. There are plans to add
many new application profiles. With over 1800 companies working on
Bluetooth, the future could not be brighter. With a strong special interest
group behind Bluetooth, the standardization of the application profiles is
almost assured.
According to market researchers, Cahners In-Stat Group, it is
anticipated that as many as 670 million products will have Bluetooth
built-in by the year 2005.
Will the speed of Bluetooth increase?
Some members of the Bluetooth SIG such as Sony & Eastman Kodak are
interested in seeing the speed of Bluetooth increasing for applications
such as streaming video. Proposals are under
Consideration but it is not clear when products based on any of the
proposals would be available.
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20. 5.0 LITERATURE SURVEY
The literature review starts with a background on Bluetooth technology which
include Bluetooth radio, device classes and connection.It then gives a
detail explanation about Bluetooth security before comparing it to other
wireless technologies. Next, it addresses the importance of cryptography in
information security, followed by an outline of basic security services that need
to be delivered in order to secure information. Part of the needs of the
security services can be fulfilled through cryptographic algorithms.This
chapter also highlights current implementations related to digital signature
by discussing PGP and SSL.Finally, this chapter identifies the most important
security services that need to be delivered in this project.
Overview of Bluetooth
Bluetooth was originally initiated by Ericsson as a cable replacement
technology
and personal ad-hoc networks. Together with Intel, IBM, Nokia and
Toshiba, they formed the Bluetooth Special Interest Group (SIG) in May 1998
that focuses onspecific areas such as engineering, qualifications and
marketing.Later, they were joinedbyother leaders in the telecommunications and
computing industry such as Lucent,Microsoft and Motorola.
Bluetooth radio and device classes
Bluetooth operates in the 2.4GHz Industrial, Scientific and Medical (ISM)
band, using the fast frequency-hopping spread spectrum (FHSS) technique.
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21. FHSS divides the frequency range into 79.1Mhz sub-channels and hops from
channel to channel 1600 times per second. Only synchronized transmitters
and receivers are able to access the transmitted data. In the ISM band,
Bluetooth technology has a maximum theoretical data rate of 1 Mbps. Actual
maximum throughput is approximately 400-700kbps depending on the channel
configurations (Gehrmann, 2002).
Bluetooth devices are divided into 3 classes of power management, that is
Class 1, Class 2 and Class 3.Table 2.1 shows the Bluetooth device classes
of power management with the corresponding operating range.
Establishing a Bluetooth connection
Bluetooth supports simultaneous connections between multiple devices in
a wireless network called a piconet. A maximum of 8 Bluetooth devices can be
active in a piconet. Each piconet has a single master device and at least one
slave device. Multiple, overlapping piconets in the same area are referred to as
a scatternet. A device can switch role when jumping from one piconet to
another. However, a device is not allowed to be a master in more than one
piconet at the same time.
A typical Bluetooth communication involves three steps: device discovery,
service discovery and pairing.In a device discovery, a Bluetooth device
detects the presence of any other Bluetooth device that is within its coverage
range.The initiating device can only detect devices that are set to
“discoverable”. Upon successful detection, the device’s “friendly name” is
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22. returned.
Afterwards, the initiating device starts a service discovery to search for
specific services offered in the other device.These services are based on
profiles defined in the Bluetooth specification. Profiles implementation in
Bluetooth devices is important to ensure interoperability of devices from
different manufacturers.Common profiles supported are Service Discovery
Application Profile, Serial Port Profile and Dial-Up Networking Profile.
This optional pairing procedure initiates a private connection between both
devices. Matching PIN or passkey is inserted in both devices before a
connection is allowed.
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23. 6.0 CONCLUSION
Bluetooth represents a great chance for sensor-networked architecture.This
architecture heralds wireless future for home and also for industrial
implementation. With a bluetooth RF link, users only need to bring the
devices with in range, and the devices will automatically link up and exchange
information.Thus implementation of blue tooth technology for sensor
networks not only cuts wiring cost but also integrates the industrial
environment to smarter Environment.
Today, with a broader specifications and a renewed concentration on
interoperability, manufacturers are ready to forge ahead and take bluetooth
products to the market place. Embedded design can incorporate the bluetooth
wireless technology into a range of new products to meet the growing demand
for connected information appliances.
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24. 7.0 REFERENCES
· www.bluetooth.com
· www.slideshare.net
· www.en.wikipedia.org/wiki/buetooth
· How Bluetooth Technology Works“Bluetooth SIG.Archived from the
original on 17January 2008. Retrieved 2008-02-01.
· www.bluetooth.org
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