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An Introduction toAn Introduction to
BLUETOOTH TECHNOLOGYBLUETOOTH TECHNOLOGY
BY Vikas Jagtap

11 February 2015 2
CONTENT
• Overview of Bluetooth History
• The Bluetooth Specifications
• Typical Bluetooth Scenario
• Protocols
• Profiles
• Security
• Comparison with other technologies
• Future of Bluetooth
• Summary

11 February 2015 3
Example : The Networked Home

11 February 2015 4
What is Bluetooth?
• “Bluetooth wireless technology is an open specification for a
low-cost, low-power, short-range radio technology for ad-hoc
wireless communication of voice and data anywhere in the
world.”
One of the first modules (Ericsson) A recent module

11 February 2015 5
Ultimate Headset

11 February 2015 6
Cordless Computer

11 February 2015 7
Bluetooth Goals & Vision
• Originally conceived as a cable replacement technology
• Short-Range Wireless Solutions
• Open Specification
• Voice and Data Capability
• Worldwide Usability
• Other usage models began to develop:
— Personal Area Network (PAN)
— Ad-hoc networks
— Data/voice access points
— Wireless telematics

11 February 2015 8
Overview of Bluetooth History
• What is Bluetooth?
— Bluetooth is a short-range wireless communications technology.
• Why this name?
— It was taken from the 10th century Danish King Harald Blatand who
unified Denmark and Norway.
• When does it appear?
— 1994 – Ericsson study on a wireless technology to link mobile phones &
accessories.
— 5 companies joined to form the Bluetooth Special Interest Group (SIG)
in 1998.
— First specification released in July 1999.

11 February 2015 9
Timeline
• 1994 : Ericsson study complete / vision
• 1995 : Engineering work begins
• 1997 : Intel agrees to collaborate
• 1998 : Bluetooth SIG formed: Ericsson, Intel, IBM, Nokia & Toshiba
• 1999 : Bluetooth Specification 1.0A
SIG promoter group expanded: 3Com, Lucent, Microsoft &
Motorola
• 2000 : Bluetooth Specification 1.0B, 2000+ adopters
• 2001 : First retail products released, Specification 1.1
• 2003 : Bluetooth Specification 1.2
• 2005 : Bluetooth Specification 2.0 (?)

11 February 2015 10
Special Interest Group

11 February 2015 11
Technical features
Connection Type
Spread Spectrum (Frequency Hopping)
& Time Division Duplex (1600 hops/sec)
Spectrum
2.4 GHz ISM Open Band (79 MHz of
spectrum = 79 channels)
Modulation Gaussian Frequency Shift Keying
Transmission Power 1 mw – 100 mw
Data Rate 1 Mbps
Range 30 ft
Supported Stations 8 devices
Data Security –Authentication Key 128 bit key
Data Security –Encryption Key 8-128 bits (configurable)
Module size 9 x 9 mm

11 February 2015 12
Bluetooth FHSS
• Employs frequency hopping
spread spectrum
• Reduce interference with
other devices
• Pseudorandom hopping
• 1600 hops/sec- time slot is
defined as 625 microseconds
• Packet 1-5 time slots long

11 February 2015 13
Time-Division Duplex Scheme
• Channel is divided into consecutive slots (each 625 µs)
• One packet can be transmitted per slot
• Subsequent slots are alternatively used for transmitting and receiving
— Strict alternation of slots between the master and the slaves
— Master can send packets to a slave only in EVEN slots
— Slave can send packets to the master only in the ODD slots

11 February 2015 14
Classification
POWER RANGE
CLASS I 20 dBm 100 m
CLASS II 0-4 dBm 10 m
CLASS III 0 dBm 1 m
• Classification of devices on the basis of Power dissipated &
corresponding maximum Range.

11 February 2015 15
Typical Bluetooth Scenario
• Bluetooth will support wireless point-to-point and
point-to-multipoint (broadcast) between devices in a
piconet.
• Point to Point Link
— Master - slave relationship
— Bluetooth devices can function as masters or slaves
• Piconet
— It is the network formed by a Master and one or more slaves
(max 7)
— Each piconet is defined by a different hopping channel to
which users synchronize to
— Each piconet has max capacity (1 Mbps)
m s
s s s
m

11 February 2015 16
Piconet Structure
Master
Active Slave
Parked Slave
Standby
• All devices in piconet hop together.
• Master’s ID and master’s clock determines frequency hopping
sequence & phase.

11 February 2015 17
Ad-hoc Network – the Scatternet
• Inter-piconet communication
• Up to 10 piconets in a
scatternet
• Multiple piconets can operate
within same physical space
• This is an ad-hoc, peer to
peer (P2P) network

11 February 2015 18
Bluetooth Protocol Stack

11 February 2015 20
Baseband
• Addressing
— Bluetooth device address (BD_ADDR)
– 48 bit IEEE MAC address
— Active Member address (AM_ADDR)
– 3 bits active slave address
– all zero broadcast address
— Parked Member address (PM_ADDR)
– 8 bit parked slave address
• This MAC address is split into three parts
— The Non-significant Address Part (NAP)
– Used for encryption seed
— The Upper Address part (UAP)
– Used for error correction seed initialization & FH sequence generation
— The Lower Address Part (LAP)
– Used for FH sequence generation

11 February 2015 21
Packet Structure
Voice
No CRC
Data CRCheader
ARQ
FEC (optional) FEC (optional)
72 bits 54 bits 0 - 2744 bits
Access
Code
Header Payload

11 February 2015 22
Connection State Machine
Standby
Inquiry Page
Connected
Transmit data
Park Hold Sniff

11 February 2015 23
Channel Establishment
• There are two managed situations
— A device knows the parameters
of the other
– It follows paging process
— No knowledge about the other
– Then it follows inquiring &
paging process
• Two main states and sub-states
— Standby (no interaction)
— Connection (working)
— Seven more sub-states for
attaching slaves & connection
establishment
Connection
State
Machine

11 February 2015 24
Channel Establishment (contd.)
• Seven sub-states
— Inquiry
— Inquiry scan
— Inquiry response
— Page
— Page scan
— Master response
— Slave response

11 February 2015 25
Link Manager Protocol

11 February 2015 26
Link Manager Protocol
• The Link Manager carries out link setup, authentication & link
configuration.
• Channel Control
— All the work related to the channel control is managed by the master
– The master uses polling process for this
— The master is the first device which starts the connection
– This roles can change (master-slave role switch)

11 February 2015 27
• Service provided to the higher layer:
— L2CAP provides connection-oriented and connectionless data
services to upper layer protocols
— Protocol multiplexing and demultiplexing capabilities
— Segmentation & reassembly of large packets
— L2CAP permits higher level protocols and applications to transmit
and receive L2CAP data packets up to 64 kilobytes in length.
L2CAP

11 February 2015 28
Middleware Protocol Group
RF
Baseband
Audio
Link Manager
L2CAP
Data
SDP RFCOMM
IP
Control
Applications
Middleware Protocol Group
•Additional transport protocols to
allow existing and new applications to
operate over Bluetooth.
•Packet based telephony control
signaling protocol also present.
•Also includes Service Discovery
Protocol.

11 February 2015 29
Middleware Protocol Group (contd.)
• Service Discovery Protocol (SDP)
— Means for applications to discover device info, services and its
characteristics.
• TCP/IP
— Network Protocols for packet data communication, routing.
• RFCOMM
— Cable replacement protocol, emulation of serial ports over wireless network.

11 February 2015 30
IP Over Bluetooth
• IP over Bluetooth v 1.0

11 February 2015 31
IP Over Bluetooth
• IP over Bluetooth v 1.1

11 February 2015 32
File Transfer Profile
• Profile provides:
• Enhanced client-server interactions:
- browse, create, transfer folders
- browse, pull, push, delete files

11 February 2015 33
Headset Profile
• Profile provides:
• Both devices must provide capability to initiate connection &
accept/terminate calls.
• Volume can be controlled from either device.
• Audio gateway can notify headset of an incoming call.

11 February 2015 34
Core Bluetooth Products
• Notebook PCs & Desktop
computers
• Printers
• PDAs
• Other handheld devices
• Cell phones
• Wireless peripherals:
• Headsets
• Cameras
• CD Player
• TV/VCR/DVD
• Access Points
• Telephone Answering
Devices
• Cordless Phones
• Cars

11 February 2015 35
Other Products…
• 2004 Toyota Prius & Lexus LS 430
— hands free calls
• Digital Pulse Oximetry System
• Toshiba Washer & Dryer
• Nokia N-gage

11 February 2015 36
Security
• Security Measures
— Link Level Encryption & Authentication.
— Personal Identification Numbers (PIN) for device access.
— Long encryption keys are used (128 bit keys).
— These keys are not transmitted over wireless. Other parameters are
transmitted over wireless which in combination with certain
information known to the device, can generate the keys.
— Further encryption can be done at the application layer.

11 February 2015 37
A Comparison
WLAN

11 February 2015 38
Bluetooth vs. IrD
• Bluetooth
— Point to Multipoint
— Data & Voice
— Easier Synchronization due
to omni-directional and no
LOS requirement
— Devices can be mobile
— Range 10 m
•IrD
—Point to point
—Intended for Data
Communication
—Infrared, LOS communication
—Can not penetrate solid objects
—Both devices must be stationary,
for synchronization
—Range 1 m

11 February 2015 39
Bluetooth: Today & Tomorrow

11 February 2015 40
Will Bluetooth become a household name?

11 February 2015 41
Future of Bluetooth
• Success of Bluetooth depends on how well it is integrated into
consumer products
— Consumers are more interested in applications than the technology
— Bluetooth must be successfully integrated into consumer products
— Must provide benefits for consumer
— Must not destroy current product benefits
• Key Success Factors
— Interoperability
— Mass Production at Low Cost
— Ease of Use
— End User Experience

11 February 2015 42
Summary
• A new global standard for data and voice
• Eliminate Cables
• Low Power, Low range, Low Cost network devices
• Future Improvements
— Master-Slave relationship can be adjusted dynamically for optimal
resource allocation and utilization.
— Adaptive, closed loop transmit power control can be implemented
to further reduce unnecessary power usage.

11 February 2015 43
“Things that think…
don’t make sense unless they
link.”
- Vikas jagtap

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