An Introduction to An Introduction to

BLUETOOTH TECHNOLOGYBLUETOOTH TECHNOLOGY

12 April 2023 2

CONTENT

• Overview of Bluetooth History

• The Bluetooth Specifications

• Typical Bluetooth Scenario

• Protocols

• Profiles

• Security

• Comparison with other technologies

• Future of Bluetooth

• Summary

12 April 2023 3

Example : The Networked Home

12 April 2023 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

12 April 2023 5

Ultimate Headset

12 April 2023 6

Cordless Computer

12 April 2023 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

12 April 2023 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.

12 April 2023 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 (?)

12 April 2023 10

Special Interest Group

12 April 2023 11

Technical features

Connection Type Spread Spectrum (Frequency Hopping) & Time Division Duplex (1600 hops/sec)

Spectrum2.4 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

12 April 2023 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

12 April 2023 13

Time-Division Duplex Scheme

• Channel is divided into consecutive slots (each 625 s)

• 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

12 April 2023 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.

12 April 2023 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

12 April 2023 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.

12 April 2023 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

12 April 2023 18

Bluetooth Protocol Stack

12 April 2023 19

Baseband

12 April 2023 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

12 April 2023 21

Packet Structure

Voice

No CRC

Data CRCheader

ARQ

FEC (optional) FEC (optional)

72 bits 54 bits 0 - 2744 bits

Access Code

Header Payload

12 April 2023 22

Connection State Machine

Standby

Inquiry Page

Connected

Transmit data

Park Hold Sniff

12 April 2023 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

12 April 2023 24

Channel Establishment (contd.)

• Seven sub-states— Inquiry

— Inquiry scan

— Inquiry response

— Page

— Page scan

— Master response

— Slave response

12 April 2023 25

Link Manager Protocol

12 April 2023 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)

12 April 2023 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

12 April 2023 28

Middleware Protocol Group

RF

Baseband

AudioLink Manager

L2CAP

Data

SDP RFCOMM

IP

Con

trol

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.

12 April 2023 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.

12 April 2023 30

IP Over Bluetooth

• IP over Bluetooth v 1.0

12 April 2023 31

IP Over Bluetooth

• IP over Bluetooth v 1.1

12 April 2023 32

File Transfer Profile

• Profile provides:• Enhanced client-server interactions:

- browse, create, transfer folders- browse, pull, push, delete files

12 April 2023 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.

12 April 2023 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

12 April 2023 35

Other Products…

• 2004 Toyota Prius & Lexus LS 430 — hands free calls

• Digital Pulse Oximetry System

• Toshiba Washer & Dryer

• Nokia N-gage

12 April 2023 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.

12 April 2023 37

A Comparison

WLAN

12 April 2023 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

12 April 2023 39

Bluetooth: Today & Tomorrow

12 April 2023 40

Will Bluetooth become a household name?

12 April 2023 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

12 April 2023 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.

12 April 2023 43

“Things that think…

don’t make sense unless they

link.”

- Nicholas Negroponte, MIT Media Laboratory

12 April 2023 44

Thank You