14736_RK-2 Bluetooth Technologies

8/7/2019 14736_RK-2 Bluetooth Technologies

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An Introduction toAn Introduction to

BLUETOOTH TECHNOLOGYBLUETOOTH TECHNOLOGY


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16 February, 2011 2

CONTENT

Overview of Bluetooth History

The Bluetooth Specifications

Typical Bluetooth Scenario

Protocols Profiles

Security

Comparison with other technologies Future of Bluetooth

Summary


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16 February, 2011 3

Example : The Networked Home


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16 February, 2011 4

What is Bluetooth?

Bluetooth wireless technology is an open specification for alow-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


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16 February, 2011 5

Ultimate Headset


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16 February, 2011 6

Cordless Computer


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16 February, 2011 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


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16 February, 2011 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 whounified 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.


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16 February, 2011 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 (?)


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16 February, 2011 10

Special Interest Group


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Technical features

Connection TypeSpread 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 KeyingTransmission Power 1 mw 100 mw

Data Rate 1 Mbps

Range 30 ft

Supported Stations8

devicesData Security Authentication Key 128 bit key

Data Security Encryption Key 8-128 bits (configurable)

Module size 9 x 9 mm


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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


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Time-Division Duplex Scheme

Channel is divided into consecutive slots (each 625Qs)

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 slavesMaster can send packets to a slave only in EVEN slots

Slave can send packets to the master only in the ODD slots


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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.


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Typical Bluetooth Scenario

Bluetooth will support wireless point-to-point andpoint-to-multipoint (broadcast) between devices in apiconet.

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


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Piconet Structure

Master

Active Slave

Parked Slave

Standby

All devices in piconet hop together.

Masters ID and masters clock determines frequency hopping

sequence & phase.


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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


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Bluetooth Protocol Stack


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Baseband


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Baseband

AddressingBluetooth 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


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Packet Structure

Voice

No CRC

Data CRC

ARQFEC (optional) FEC (optional)

72 bits 54 bits 0 - 2744 bits

Access

CodeHeader Payload


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ecti tate ac i e

Standby

Inquiry Page

Connected

Transmit data

Park Hold Sniff


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Channel Establishment

There are two managed situations

A device knows the parameters of

the other

It followspagingprocess

No knowledge about the other Then it follows inquiring &

pagingprocess

Two main states and sub-states

Standby (no interaction)

Connection (working)

Seven more sub-states for

attaching slaves & connection

establishment

Connection

State

Machine


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Channel Establishment (contd.)

Seven sub-states

Inquiry

Inquiry scanInquiry response

Page

Page scan

Master responseSlave response


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Link Manager Protocol


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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 usespollingprocess for this

The master is the first device which starts the connection

This roles can change (master-slave role switch)


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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


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Mi le are r t c l r u

RF

Baseband

AudioLink Manager

L2CAP

Data

SDP RFCOMM

IP

Applications

Middleware Protocol Group

Additional transport protocols to

allow existing and new applications to

operate over Bluetooth.

Packet based telephony controlsignaling protocol also present.

Also includes Service Discovery

Protocol.


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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.


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IP Over Bluetooth

IP over Bluetooth v 1.0


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IP Over Bluetooth

IP over Bluetooth v 1.1


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File Transfer Profile

Profile provides: Enhanced client-server interactions:

- browse, create, transfer folders

- browse, pull, push, delete files


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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.


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Core Bluetooth Products

Notebook PCs & Desktopcomputers

Printers

PDAs

Other handheld devices

Cell phones

Wireless peripherals:

Headsets

Cameras

CD Player

TV/VCR/DVD

Access Points

Telephone AnsweringDevices

Cordless Phones

Cars


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Other Products

2004 Toyota Prius & Lexus LS 430 hands free calls

Digital Pulse Oximetry System

ToshibaW

asher & Dryer Nokia N-gage


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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.


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A Comparison

WLAN


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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

CommunicationInfrared, LOS communication

Can not penetrate solid objects

Both devices must be stationary,

for synchronizationRange 1 m


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Bluetooth: Today & Tomorrow


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Will Bluetooth become a household name?


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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

InteroperabilityMass Production at Low Cost

Ease of Use

End User Experience


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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.


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Things that think

dont make sense unless they link.

- Nicholas Negroponte, MIT Media Laboratory


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Thank You

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14736_RK-2 Bluetooth Technologies

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