Bluetooth technology electronics engineering

1. 1
BLUETOOTH
TECHNOLOGY
A revolution in wireless
communication

2. 2
ROAD MAP
 Introduction
 Basic Definitions
 Topology
 Protocols
 Link Management & Security
 Applications and Future

3. 3
Introduction
 Aim :- To replace cables between mobiles, PC
cards, headsets, desktops and other devices.
 Developed by Special Interest Group (SIG)
 Association of I.T majors like Intel, IBM,
Nokia and Toshiba

4. 4
Bluetooth Verses Infrared
 Slower than IR as time
taken to discover the
intended recipient
 Penetration of solid
objects
 Omni directional
 Advantage of proximity
so less time requirement
 No such feature
 Unidirectional with 30
degrees range

5. 5
BT Verses IR
 Data transfer rate 721
Kbps
 30 feet range
 Mobility during data
transfer
 Internet compatible
(emulating EIA TIA 232)
 Rate is 4 Mbps
 Range very less
 Relatively stationary

6. 6
Bluetooth Definitions
 Piconet : Collection of
devices connected via
Bluetooth in ad hoc
fashion. Limited to 8
units in a Piconet
 Scatternet : Two or
more independent
unsynchronized Piconet.

7. 7
Definitions
 Master : A device in
Piconet whose clock
and hopping sequence
are used to
synchronize all the
devices. It also
numbers the
communication
channels

8. 8
Definitions
 Slave : All other devices
in the Piconet except
master
 MAC : 3-bit media
access control address
used to differentiate
between participating
units

9. 9
Bluetooth technology
 Implemented using short range transreceivers
 Specifications comprises a system solution
consisting of a hardware, a software &
interoperability requirements
 Uses globally available unlicensed ISM radio
band of 2.4 GHz.
 Frequency range 2.4 – 2.484 GHz

10. 10
BT technology
 Advantage of using an unlicensed frequency
band is that it is globally acceptable

11. 11
Types of Links
 Asynchronous Connection Links (ACL)
 Supports symmetrical, asymmetrical, packet-
switched & point to multipoint links
 Data Transfer Rate: 433.9 Kbps(sym.)
 732.2 Kbps in one, 57.6 Kbps in
reverse(asymmetric)

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Types of Links
 Synchronous Connection Oriented Links
(SCO)
 Provide symmetrical, circuit-switched & point to
point connections

13. 13
Audio and Video
 For voice coding 64 Kbps channels are
required
 Channels are derived through use of PCM or
CVSDM
 Video encoding decoding using MPEG –4
format
 Radio links use freq. hopping spread spectrum
techniques

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Spread Spectrum
 Method of wireless communication that takes a
narrow band signal and spreads it over a
broader portion of the available frequency
band.
 CDMA applies the same concept

15. 15
Advantages of Spread
Spectrum Technique
 Prevents Interference : where transmission
disruption by external source such as noise from
electromagnetic devices.
 Prevents Jamming : where stronger signal
overwhelms the weaker one.
 No reflection off solids.
 No interception : where unauthorized users
capture signal to determine the content.

16. 16
Performance Characteristics
FeaturesFunctions Performance
1.Connection Type
2.Spectrum
3.Transmission Power
4.Aggregate Data Rate
5.Range
6.Supported stations
Spread spectrum
2.4GHz. ISM band
1 milliwatt
1 Mbps using frequency
hopping
Up to 30 feet
Up to 8 devices per
piconet

17. 17
FeaturesFunctions Performance
Voice Channels Up to 3
Data Security For authentication a 128
bit key; for encryption
key size configurable (8-
128 bits)
Addressing Each bit has 48 bit MAC
address

18. 18
Bluetooth Topology
 Ad-hoc connection where each Piconet is identified
by a different hopping sequence
 Synchronization in unlicensed ISM band not
permitted but BT devices do it using TDM
 Service discovery protocol allows wider applications
ex: create LAN
 Clustering avoided using technical safeguards.

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Bluetooth Protocols
 Bluetooth Protocol Layers
 Bluetooth Core Protocols (Baseband, LMP,
L2CAP, SDP)
 Cable Replacement Protocols (Radio Freq.
Communication)
 Telephony Control Protocols (TCSBIN, AT-
Commands)
 Adopted Protocols (PPP, TCP, OBEX, WAP,
vCard, vCalender)

20. 20
LMP and SDP
 LMP : responsible for link setup & control
between Bluetooth devices, including the
control and negotiations of baseband packet
sizes
 SDP : device information, services and
characteristics of services can be queried.

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BLUETOOTH
LINK MANAGEMENT

22. 22
Link Management
 Peer to Peer communication using LMP
 Link Manager
 Messages Exchanged (PDU’s)
 Within 30 seconds
 PDU
 55 different types of PDU’s
 7 bit op code

23. 23
AUTHENTICATION
 General Response Messages
 LMP_accepted
 LMP_not_accepted
 Challenge- Response Scheme
 Verifier sends(LMP_au_rand)
 Response is a function of challenge ,Claimant ‘s
(BD_ADDR)&Secret Key
 Common Secret key is required for proper calculation

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PAIRING
 When no Common Link Key:
 128 bit Initialization Key based on PIN and
random no.
 Calculation of Response on key
 Verifier Approves the Link Key
 Response not correct then Error
 Code authentication failure (LMP_detach)

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 Link Key is Created after authentication
 Link Key Created may be either
combination of Keys or one of the unit’s
unit key(LMP_unit _key &
LMP_comb_key)
 Waiting Interval:
 Increased exponentially

26. 26
ENCRYPTION
 Is an Option.
 Master’s Will in piconet
 Master & Slave must Agree
 Point to Point or also broadcast packet’s

27. 27
ENCRYPTION
Start Stop
 Master is configured to
Transmit unencrypted
packets and receive
encrypted .
 Slave is configured To
Transmit and Receive
encrypted packets
 Master is configured to
Transmit and Receive
encrypted packets
 Master is configured to
Transmit encrypted and
receive unencrypted .
 Slave is configured To
Transmit and Receive
unencrypted .
 Master is configured to
Transmit and Receive
unencrypted .

28. 28
Clock Offset Request
 Every Device has an Internal System Clock
 Timing and frequncy determined by the master in
Piconet.
 Difference between slave’s and master’s.
 Clock offset is updated on each time a packet
is received.

29. 29
BLUETOOTH SECURITY
 Built in Security
 Frequency Hopping
 Pseudorandom code sequence
 Lasts 0.4 seconds
 75 channels in 2.4GHZ
 Authentication preventing spoofing unwanted access
 Encryption makes data unintelligible.
 Inhibiting user-friendly hence 3 levels of security.

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Security Modes
 Mode 1:
 Absence of security (Bypassing Link –Level security
functions)
 Exchange of vCard and vCalenders
 Mode 2:
 Service Level Security for parallel applications
 Mode 3:
 Link Level Security
 LM enforces security at connection set up.
 Link Keys

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 Key Length(8 and 128 bits)
 128 bit challenge and 32 bit response .
 Depends on Level of Security
 Maximum length limited by Hardware

32. 32
LAYOUT
 FIELDS OF APPLICATION.
 BLUETOOTH ADVANTAGE
 SHORTCOMINGS OF THE TECHNOLOGY.
 COMPARISON WITH IR & WLAN.
 MISNOMERS.
 RESEARCHES ON THE TECHNOLOGY.
 FUTURE ASPECTS.

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APPLICATIONS
 WAP enabled smart phones.
 Electronic trading via handheld devices.
 ad hoc Home/personal area network.
 3G Telephony.

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BLUETOOTH ADVANTAGE
 Increased mobility in office by connecting
various peripherals with BT.
 Voice and data transmission possible
 721 kbps suffices most of the common uses.
 Built in sufficient encryption and
authentication.
 Cheaper insatllation & maintainence.

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ERROR CORRECTION
 1/3 rate FEC (Forward Error Correction)
 2/3 rate FEC
 ARQ unnumbered scheme (Automatic Repeat
Request).
 This reduces the available bandwidth.

36. 36
RADIATION THREATS
 Penetration depth of RF is about 1.5 cm at
2450 MHz and about 2.5 cm at 900 MHz
 It cannot generate enough heat to produce fire
hazards.
 Radiation not beamed but dispersed in all
direction.
 But in long run EM radiation can cause ill
effects in some persons.

37. 37
LOOPHOLES IN SECURITY
 Key initialization is not reliable.
 Unit key can leak the information in traffic.
 BT device address can be used to generate logs
of transaction.
 Battery draining denial of service scheme.

38. 38
BLUETOOTH v/s INFRARED
BT IrDA
Range-10 to 100 m 20 cm to 2 m
Omnidirectional comm. Bidirectional comm.
Peak data rate- 1mbps 16 mbps
Can support 8 devices in
piconet
2 devices can interact
at time

39. 39
BLUETOOTH vs WLAN
WLAN BT
Vendors Proxim, 3COM,
Symbol, Cisco
Most chip
vendors
SPEED 11-54 Mbps 1-2 Mbps
No. of access pts
required
Every 200 feet Every 30 feet
Distance
coverage
Upto 300 feet Upto 30 feet
interference 2.4 GHz band is
significant here
polluted
interference
Cost expensive Cheaper
(Rs1200-300)

40. 40
IrDa Response
 Infra com launches RED BEAMER
technology.
 Indirect and diffused IR will increase mobility
of IR devices.
 Transmission at only 56kbps.

41. 41
BLUETOOTH FACTS
 Its not WLAN. Data throughput is much less
in BT.
 BT can jam WLAN as both use 2.4GHz RF.
 Not designed to carry heavy traffic loads.
 Not suitable in server-based applications.

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PIONEERS IN RESEARCH
 IBM- Watch pad and cyber phones.
 MS- Intelligent apps for Windows.
 INTEL-wireless PC Cards, access points.
 MOTOROLA & TOSHIBA-pc mobile
interface via bluetooth.
 GENERAL MOTORS- Better communication
in cars.
 NEC-launched BT enabled notebook.

43. 43

44. 44
BLUETOOTH FUTURE
 100 million devices in use and around 2005
650 million devices will be deployed.
 19% vehicles will be bluetooth enabled by
2007.

45. 45
SOME PRODUCTS IN
MARKET
 Ericsson R520 Bluetooth/WAP/GPRS/Triband
 Ericsson T36 Bluetooth/WAP/HSCSD/Triband
 Alcatel OneTouch 700 GPRS, WAP, Bluetooth
 TDK Bluetooth Product Range
 Bluetooth-enabled Nokia 9110 linked to a FujiFilm
digital camera
 Ericsson Bluetooth GSM Headset
 Ericsson Communicator

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REFRENCES
 www.countersys.com/tech/bluetooth.html
 www.bluetooth.com
 www.cnet.com
 www.motorola.com
 www.palowireless.com
 www.swedetrack.com
 www.mobileinfo.com
 www.computer.org
 www.informit.com
 www.erricsson.com