Introduction to Bluetooth™ Wireless Technology

Introduction to Bluetooth™ Wireless Technology Jon Inouye Staff Software Engineer Mobile Platforms Group Intel Corporation Bluetooth Bluetoothisisaatrademark trademarkowned ownedby byBluetooth BluetoothSIG SIGInc. Inc.USA USA IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Radio Technology l

Cellular – Licensed spectrum – Voice driven – Data services emerging – E.g., 3G, GPRS, WAP*

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Wireless LAN – Proliferation occurring – E.g., IEEE 802.11b

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WWAN Km WLAN 100 m text text

WPAN 10 m

Wireless PAN – Relative newcomer – E.g., Bluetooth*, 802.15

*Third-party marks and brands are the property of their respective owners.

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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WHAT IS BLUETOOTH? Applications

Data Audio

Co ntro l

TCP/IP HID RFCOMM

L2CAP Link Manager

Baseband RF l

a hardware description

l

an application framework IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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OUTLINE l Radio l Baseband l Connection Management l Channel Operation l Piconet Management

l Software Stack l Profiles

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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RADIO

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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RADIO PARAMETERS (1) l Frequency hopping l ISM band at 2.45 GHz l 2402 + k MHz, k = 0, …, 78 l device-specific hopping sequence l nominal rate 1600 hops/s

l Modulation l binary FSK l Gaussian shaping l BT = 0.5; 0.28 < h < 0.35 l -20dB bandwidth of 1 MHz IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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RADIO PARAMETERS (2) l Transmit power l nominal 0 dBm l up to 20 dBm provided power control

l Receiver sensitivity l -70 dBm @ 0.1% BER

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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BASEBAND OPERATIONS DISCOVERY AND CONNECTION ESTABLISHMENT

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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INQUIRY l Radio wanting to discover other radios l Repetitively probe first set of 16 frequencies l Probes two frequencies every 625 microseconds l Repeat at least 256 times l Repetitively probe second set of 16 frequencies l Repeat entire cycle at least two times

l Radio wanting to be discovered l Listen to one of 32 frequencies for at least 11.25 ms l Sleep no longer than 2.56 seconds l Wake up and listen to another frequency l Repeat cycle

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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INQUIRY OPERATION

A

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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CREATING A PICONET

A

page B

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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CREATING A PICONET

master A

connected slave B

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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CREATING A PICONET

slave C slave D

master A

slave B

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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OPERATIONAL STATES

master active slave parked slave standby IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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ADDRESSING l Bluetooth Device Address (BD_ADDR) l 48-bit IEEE 802 address l 24-bit lower address part (LAP) l 8-bit upper address part (UAP)

l Active Member Address (AM_ADDR) l 3-bit active slave address l all-zero broadcast address

l Parked Member Address (PM_ADDR) l 8-bit parked slave address

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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BASEBAND OPERATIONS PICONET CHANNEL

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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FH/TDD CHANNEL f(2k)

f(2k+1)

f(2k+2)

master t

slave t 625 µs

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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FREQUENCY HOPPING

freq 2.402

2.480

master slave

time

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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PHYSICAL CHANNEL l master BD_ADDR → hop sequence l master CLOCK

→ phase slave 2 slave 1 master

slave 3

slave 4

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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HOP SELECTION

phase

NATIVE CLK

HOP sequence

offset

MASTER BD_ADDR

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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PACKET FORMAT

72b

0-2745b

54b

access code packet header

payload

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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ACCESS CODE 34

24

6

PRT

LAP

BRK

4

PREAMBLE LSB

64

SYNC WORD

4

TRAILER MSB

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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ACCESS CODE TYPES l Device

access code (DAC)

unit identifier l derived from unit LAP l

l Channel

access code (CAC)

channel identifier l derived from master LAP l

l Inquiry

access code (IAC)

reserved identifier l derived from reserved address l

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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PACKET HEADER 3

AM_ADDR

4

1

TYPE

FLOW

parameter AM_ADDR

1

ARQN

1

SEQN

8

HEC

information slave active member address

TYPE

payload type

FLOW

LC flow control

ARQN

ACK/NAK

SEQN

retransmit ordering

HEC

header error check

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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PHYSICAL LINK DEFINITION

Purpose: Mixing:

MULTI-MEDIA SUPPORT l circuit switching l packet switching

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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PHYSICAL LINK TYPES l Synchronous Connection-Oriented (SCO) Link l circuit switching l symmetric, synchronous services l slot reservation at fixed intervals

l Asynchronous Connection-Less (ACL) Link l packet switching l (a)symmetric, asynchronous services l polling access scheme

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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MIXED LINK EXAMPLE SCO

ACL

SCO

ACL

ACL

SCO

SCO

ACL

MASTER

SLAVE 1

SLAVE 2

SLAVE 3

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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PACKET TYPES segment

1

2

3

4

type 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111

SCO link ACL link NULL POLL FHS DM1

NULL POLL FHS DM1 DH1

HV1 HV2 HV3 DV AUX1 DM3 DH3

DM5 DH5

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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MULTI-SLOT PACKETS 625 µs f(k)

f(k+1)

f(k+2)

f(k)

f(k+3)

f(k+4)

f(k+5)

f(k+3)

f(k+4)

f(k+5)

f(k)

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

f(k+5)

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DATA RATES (kb/s) type

symmetric

asymmetric

DM1

108.8

108.8

108.8

DH1

172.8

172.8

172.8

DM3

258.1

387.2

54.4

DH3

390.4

585.6

86.4

DM5

286.7

477.8

36.3

DH5

433.9

723.2

57.6

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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LINK CONTROL PACKETS l ID packet l NULL packet l POLL packet l FHS packet

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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FHS PACKET l BD_ADDR l DAC l AM_ADDR l class of device l paging class l real-time clock

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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ERROR CORRECTION l Forward-Error Correction (FEC) l 1/3 rate: bit-repeat code l 2/3 rate: (15,10) shortened Hamming code

l Automatic Retransmission Query (ARQ) l 1-bit fast ACK/NAK l 1-bit sequence number l header piggy-backing

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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ARQ OPERATION A

B

B

X

C

MASTER

SLAVE 1

SLAVE 2

G

F

H

Z

Z

NAK

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

ACK

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CVSD WAVEFORM CODING

1 1 0 0 0 0 0 0 1 0 1 1 1 1 1 0 1 0 0 0 0 1 1 1 0 0 0 1 0 1 0 1 0 . . . . . . .

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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BASEBAND OPERATIONS PICONET MANAGEMENT

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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OPERATIONAL STATES l

stand-by, scan

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page, inquiry

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connection active l hold l sniff l park l

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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SIMPLIFIED STATE MACHINE Unconnected Standby

Standby De tac h

l

– Waiting to join a piconet l

Inquire

Connecting States

– Discover radios l

Page Active States

Page

Transmit data AMA

Ttypical=0.6s

Connected AMA

Connected Ttypical=2 ms

– Active on a piconet l

Inquiry

Ttypical=10.25s

– Connect to a specific radio l

Standby

Park/Hold/Sniff – Low Power connected states

Low Power States

Releases AMA Address

PARK PMA

Ttypical=2 ms

SNIFF

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

HOLD AMA

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HOLD MODE ACL

ACL

ACL

ACL

ACL

ACL

ACL

MASTER

LOST

SLAVE 1

HOLD INTERVAL

SLAVE 2

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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SNIFF MODE ACL

ACL

ACL

MASTER

LOST

SLAVE 1

SNIFF INTERVAL

SLAVE 2

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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PARK MODE active slave

master

parked slaves

l BEACON l PM_ADDR

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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PARK MODE PARK INTERVAL BC

ACL

ACL

BC

MASTER

SLAVE X

SLAVE 2

SLAVE Y

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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SCATTERNET slave 3 slave 1

slave 6

master A

slave 4 / master B

slave 5 slave 2

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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BASEBAND OPERATIONS SECURITY

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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SECURITY COMPONENTS

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Authentication

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Payload encryption

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Key handling

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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AUTHENTICATION l

To verify claimed identity

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Challenge-response system

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Algorithm E1: l Input: RAND (128 bit), Claimant addr. (48 bit), link key (128) SRES (32 bit), ACO (96 bit) l Output:

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One-sided or mutual authentication ACO = Authenticated Ciphering Offset

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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ENCRYPTION l

To prevent (un)intentional eavesdropping

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Stream ciphering

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Algorithm E0: l Input: RAND (128 bit), master addr./clock, Kc (128 bit) l Output: cipher stream

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LFSR restart for every slot

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Encryption of payload only

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Point-to-point or point-to-multipoint

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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KEY TYPES Link Linkkeys keys Encryption Encryption key key

Temporary Temporary

Master Master Key Key

Semi-permanent Semi-permanent

Unit Unit Key Key

Combination Combination Key Key

Initialization Initialization Key Key

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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RADIO/BB SUMMARY l Frequency hopping radio at 2.4 GHz l Intrinsic support for voice and data l Maximum 723 Kbps MAC throughput l Low power modes l Point-to-multipoint configuration l Support of basic security mechanisms

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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SOFTWARE STACK

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Outline l l l l

Software scope and goals Protocol Review Profile Review Summary

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Software Architecture Applications SDP

RFCOMM

Cover This

Co ntro l

TCS

Data L2CAP Audio

Link Manager

LMP LMP

Baseband RF IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Software Architecture Goals l l l

Support the target usage models Support a variety of hardware platforms Protocol reuse – Avoid duplicating existing technology – Promote better harmonization across technologies

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Good “out of box” user experience – Interoperability

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Outline l l l l

Software goals Protocol Review Profile Review Summary

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Bluetooth Protocol Stack Still Image

HID Service Discovery

WAE

vCard/vCal*

WAP*

OBEX* TCP/UDP

Audio Printing

RFCOMM

IP

TCS L2CAP

Host Controller Interface *Third-party marks and brands are the property of their respective owners. IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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HCI

Bluetooth Host Host Drives and Applications

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Host Controller Interface (HCI) provides a common interface between the Bluetooth Host and the Bluetooth Module HCI

Bluetooth HCI driver Bluetooth HCI Transport driver

(USB*, PC Card*, PCI*)

Transport Bus HCI Transport Firmware

Bluetooth Host Controller Link Manager Bluetooth Baseband *Third-party marks and brands are the property of their respective owners.

Bluetooth Radio Bluetooth Module

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Link Layer Control and Adaptation Protocol l l l

Also known as L2CAP Basic data link layer protocol over Baseband Support for: – Protocol Multiplexing – Segmentation and Reassembly (SAR) – Quality of Service – Groups

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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L2CAP Architecture l

Connection-oriented – Channel identifier (CID) used to label each connection endpoint – Channels may be uni-directional or bi-directional – QoS flow specification assigned to each channel direction

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Connectionless – Supports group abstraction

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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L2CAP Channels Connection-Oriented Data Channel Connectionless Data Channel

CID

Device #1

CID

CID

CID

CID

L2CAP

CID

L2CAP

CID

L2CAP Signalling Channel

L2CAP

Device #2

CID

CID

L2CAP

L2CAP

Device #3

Device #4

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Service Discovery Protocol l

Bluetooth SDP enables Bluetooth devices to discover the characteristics and capabilities of other Bluetooth devices within RF proximity

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Within Bluetooth SDP, a service is: – any information, resource, or facility that is provided by (or through) one Bluetooth device that is advertised as available to nearby Bluetooth devices

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Bluetooth SDP does not provide a general purpose service access/usage mechanism; SDP only enables discovery of services

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Service Discovery l

Two parts – Service record format – Information about service provided by attributes – Attributes composed of an ID and a value – Ids may be universally unique identifiers (UUID) – Session protocol for enabling discovery – Searching for and browsing services

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Typical SDP Client/Server Interactions Server

Client ServiceSearchRequest(SearchPattern)

ServiceSearchResponse(ServiceRecordHandleList)

ServiceAttributeRequest(ServiceRecordHandle, AttributeIDList) ServiceAttributeResponse(AttributeList)

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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SDP Scope l

Many Service Discovery Protocols – Service Location Protocol (SLP), Jini*, Universal Plug and Play (UPnP*), etc.

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Bluetooth SDP focuses on service discovery within Bluetooth environment

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SDP does not compete with other technologies.

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SDP compliments them by enabling their use in Bluetooth environments

*Third-party marks and brands are the property of their respective owners.

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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RFCOMM l

l

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Supports a large base of legacy applications using the serial port as the primary communications mechanism. Reuse GSM TS 07.10 as an existing standard for multiplexing a single physical channel and V.24 emulation. Designed to allow multiple “ports” over a single physical channel between a PC and a GSM handset

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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TCS Protocol l Telephony

Control Protocol Specification

Group management Call Control Gateway may serve more Call setup and release cordless devices Symmetrical derivative of Distributes group information Q.931

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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TCS Impact l

Cordless Telephony Example – Phone moves into range of voice access point and establishes link – Phone link placed into a low power state – Incoming call is broadcast to all phones – On answer, a voice (SCO) link is setup

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Intercom – Supports direct phone-to-phone communication

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Reuse and Recycle l

Desire to reuse IrDA* applications on mobile phones and PCs – Decision to merge with IrDA’s OBEX (Object Exchange) protocol on top of RFCOMM or TCP. – Enables harmonized API across PAN technologies

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Interaction with applications on phones – Handset manufacturers have agreed on an application framework called WAP*. – Bluetooth is treated as a WAP “bearer” in a manner similar to GSM. – Reuse “browser” interface on mobile phone. *Third-party marks and brands are the property of their respective owners.

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Outline l l l l

Software goals Protocol Review Profile Review Summary

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Interoperability and Profiles l

Protocols define the communication language spoken between devices

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How do you avoid the “Tower of Babel” problem?

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Solution: Mandate the language spoken for a given usage model

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Profiles l l l l

Represents the default solution for a specific usage model “Vertical slice” through the protocol stack Basis for interoperability and logo requirements Each Bluetooth device supports one or more profiles

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Protocols and Profiles

Relationship between Protocols and Profiles

Protocols

Applications

Profiles IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Profiles in the Bluetooth Specification 1.1 Generic Access Profile TCS-BIN-based Profiles Service Discovery Application Profile

Cordless Phone Profile

Intercom Profile

Serial Port Profile Dial-up Networking Profile Fax Profile

Headset Profile

LAN Access Profile

Generic Object Exchange Profile File Transfer Profile Object Push Profile

Synchronization Profile

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Example: Dialup Networking Profile PPP AT Commands

RFCOMM L2CAP LMP

ACL SCO Bluetooth Baseband IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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Software Summary l Protocols l Profiles l Existing

defined for communication

defined to promote interoperability protocols used where possible

IEEE Oregon Section Bluetooth Seminar – April 27, 2001

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