Introduction to Blue Tooth Wireless Technology

transcript

IEEE Oregon Section Bluetooth Seminar – April 27, 2001 1

Introduction to Bluetooth™ Introduction to Bluetooth™ Wireless TechnologyWireless Technology

Jon InouyeJon InouyeStaff Software EngineerStaff Software Engineer

Mobile Platforms GroupMobile Platforms Group

Intel CorporationIntel Corporation

Bluetooth is a trademark owned by Bluetooth SIG Inc. USABluetooth is a trademark owned by Bluetooth SIG Inc. USA

Radio TechnologyRadio Technology

ll CellularCellular–– Licensed spectrumLicensed spectrum–– Voice drivenVoice driven–– Data services emergingData services emerging–– E.g., 3G, GPRS, WAP*E.g., 3G, GPRS, WAP*

ll Wireless LANWireless LAN–– Proliferation occurringProliferation occurring–– E.g., IEEE 802.11bE.g., IEEE 802.11b

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

WPAN10 m

WLAN100 m

WWANKm

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

WHAT IS BLUETOOTH?WHAT IS BLUETOOTH?

ll a hardware descriptiona hardware description

ll an application frameworkan application framework

RFBaseband

AudioLink ManagerL2CAP

TCP/IP HID RFCOMM

Applications

l Radiol Basebandl Connection Managementl Channel Operationl Piconet Management

l Software Stackl Profiles

OUTLINE

l Frequency hoppingl 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 Modulationl binary FSK

l Gaussian shapingl BT = 0.5; 0.28 < h < 0.35

l -20dB bandwidth of 1 MHz

RADIO PARAMETERS (1)

l Transmit powerl nominal 0 dBm

l up to 20 dBm provided power control

l Receiver sensitivityl -70 dBm @ 0.1% BER

RADIO PARAMETERS (2)

BASEBAND OPERATIONS

DISCOVERYAND

CONNECTION ESTABLISHMENT

INQUIRY

l Radio wanting to discover other radiosl Repetitively probe first set of 16 frequenciesl Probes two frequencies every 625 microsecondsl Repeat at least 256 timesl Repetitively probe second set of 16 frequenciesl Repeat entire cycle at least two times

l Radio wanting to be discoveredl Listen to one of 32 frequencies for at least 11.25 msl Sleep no longer than 2.56 secondslWake up and listen to another frequencyl Repeat cycle

INQUIRY OPERATION

CREATING A PICONET

slave B

master A

connected

slave B

master A

slave Cslave D

CREATING A PICONET

active slave

master

parked slave

standby

OPERATIONAL STATES

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

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

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

ADDRESSING

BASEBAND OPERATIONS

PICONET CHANNEL

625 µs

master

f(2k) f(2k+1) f(2k+2)

FH/TDD CHANNEL

2.402 2.480freq

timeslave

master

FREQUENCY HOPPING

lmaster BD_ADDR → hop sequence

lmaster CLOCK → phase

master

slave 2

slave 1

slave 4slave 3

PHYSICAL CHANNEL

NATIVE CLK HOP

MASTER BD_ADDR

sequence

offset

HOP SELECTION

access code packet header payload

72b 54b 0-2745b

PACKET FORMAT

PREAMBLE SYNC WORD TRAILER

4 64 4

34 24 6

LSB MSB

PRT LAP BRK

ACCESS CODE

ACCESS CODE TYPESACCESS CODE TYPES

ll Device access code (DAC)Device access code (DAC)ll unit identifierunit identifierll derived from unit LAPderived from unit LAP

ll Channel access code (CAC)Channel access code (CAC)ll channel identifierchannel identifierll derived from master LAPderived from master LAP

ll Inquiry access code (IAC)Inquiry access code (IAC)ll reserved identifierreserved identifierll derived from reserved addressderived from reserved address

AM_ADDR HEC

AM_ADDR

slave active member address

payload type

LC flow control

ACK/NAK

parameter information

SEQNTYPE

SEQN retransmit ordering

HEC header error check

PACKET HEADER

Purpose: MULTI-MEDIA SUPPORT

Mixing:

PHYSICAL LINK DEFINITION

l circuit switchingl packet switching

l Synchronous Connection-Oriented (SCO) Linkl circuit switchingl symmetric, synchronous servicesl slot reservation at fixed intervals

l Asynchronous Connection-Less (ACL) Link

l packet switchingl (a)symmetric, asynchronous servicesl polling access scheme

PHYSICAL LINK TYPES

MASTER

SLAVE 1

SLAVE 2

SLAVE 3

ACLSCO SCO SCO SCOACLACL ACL

MIXED LINK EXAMPLE

0000000100100011

NULLPOLLFHSDM1

0100010101100111

HV1HV2HV3

DV10001001101010111100

DM3DH33

110111101111

DM5DH54

typesegment ACL linkSCO link

PACKET TYPES

625 µs

f(k+1) f(k+2) f(k+3) f(k+4)

f(k+3) f(k+4)f(k)

f(k+5)

MULTI-SLOT PACKETS

type symmetric asymmetric

DATA RATES (kb/s)

l ID packet

l NULL packet

l POLL packet

l FHS packet

LINK CONTROL PACKETS

l BD_ADDR

l AM_ADDR

l class of device

l paging class

l real-time clock

FHS PACKET

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

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

ERROR CORRECTION

MASTER

SLAVE 1

SLAVE 2

A B B CX

NAK ACK

ARQ OPERATION

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 . . . . . . .

CVSD WAVEFORM CODING

BASEBAND OPERATIONS

PICONET MANAGEMENT

OPERATIONAL STATES

l stand-by, scan

l page, inquiry

l connectionl activel holdl sniffl park

SIMPLIFIED STATE MACHINE

ll StandbyStandby–– Waiting to join a piconetWaiting to join a piconet

ll InquireInquire–– Discover radiosDiscover radios

ll PagePage–– Connect to a specific radioConnect to a specific radio

ll ConnectedConnected–– Active on a Active on a piconetpiconet

ll Park/Hold/SniffPark/Hold/Sniff–– Low Power connected statesLow Power connected states

Inquiry Page

ConnectedAMA

TransmitdataAMA

Ttypical=0.6s

Ttypical=10.25s

HOLDAMA

PARKPMA

Ttypical=2 ms Ttypical=2 ms

ReleasesAMA

AddressLow Power

States

ActiveStates

Standby

ConnectingStates

UnconnectedStandby

MASTER

SLAVE 1

SLAVE 2

HOLD MODE

HOLD INTERVAL

ACL ACL ACL ACL ACL

MASTER

SLAVE 1

SLAVE 2

ACL ACL ACL

SNIFF MODE

SNIFF INTERVAL

active slave

parked slaves

l BEACON

l PM_ADDR

PARK MODE

master

MASTER

SLAVE X

SLAVE 2

PARK INTERVAL

SLAVE Y

BC BCACL

PARK MODE

slave 1

slave 2

slave 3

slave 4 / master B

slave 6

slave 5

SCATTERNET

master A

BASEBAND OPERATIONS

SECURITY

SECURITY COMPONENTS

l Authentication

l Payload encryption

l Key handling

AUTHENTICATIONAUTHENTICATION

ll To verify claimed identityTo verify claimed identity

ll ChallengeChallenge--response systemresponse system

ll Algorithm Algorithm EE11::ll Input: RAND (128 bit), Claimant Input: RAND (128 bit), Claimant addraddr. (48 bit), . (48 bit),

link key (128)link key (128)ll Output:Output: SRESSRES (32 bit), (32 bit), ACOACO (96 bit)(96 bit)

ll OneOne--sided or mutual authenticationsided or mutual authentication

ACO = Authenticated Ciphering Offset

ENCRYPTIONENCRYPTION

ll To prevent (un)intentional eavesdroppingTo prevent (un)intentional eavesdropping

ll Stream cipheringStream ciphering

ll Algorithm Algorithm EE00::ll Input: RAND (128 bit), master Input: RAND (128 bit), master addraddr./clock,./clock,

KKcc (128 bit)(128 bit)ll Output: cipher streamOutput: cipher stream

ll LFSR restart for every slotLFSR restart for every slot

ll Encryption of payload onlyEncryption of payload only

ll PointPoint--toto--point or pointpoint or point--toto--multipointmultipoint

KEY TYPESKEY TYPES

Link keysLink keys

InitializationKey

TemporaryTemporary

MasterKey

Semi-permanentSemi-permanent

UnitKey

CombinationKey

Encryption keyEncryption key

RADIO/BB SUMMARYRADIO/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

SOFTWARE STACK

OutlineOutlinell Software scope and goalsSoftware scope and goalsll Protocol ReviewProtocol Reviewll Profile ReviewProfile Reviewll SummarySummary

Software ArchitectureSoftware Architecture

Baseband

AudioLink Manager

LMPLMPL2CAP

TCS SDP RFCOMM

Applications

rol Cover This

Software Architecture GoalsSoftware Architecture Goalsll Support the target usage modelsSupport the target usage modelsll Support a variety of hardware platformsSupport a variety of hardware platformsll Protocol reuseProtocol reuse

–– Avoid duplicating existing technologyAvoid duplicating existing technology–– Promote better harmonization across technologiesPromote better harmonization across technologies

ll Good “out of box” user experienceGood “out of box” user experience–– InteroperabilityInteroperability

OutlineOutlinell Software goalsSoftware goalsll Protocol ReviewProtocol Reviewll Profile ReviewProfile Reviewll SummarySummary

Bluetooth Protocol StackBluetooth Protocol Stack

OBEX*WAP* Printing

Host Controller Interface

Still Image

TCP/UDP RFCOMM

IPService Discovery

AudiovCard/vCal*WAE

Bluetooth Host

Bluetooth Module

HCI Transport Firmware

Host Drives and Applications

Bluetooth HCI Transport driver (USB*, PC Card*, PCI*)

Transport Bus

Bluetooth HCI driver

Bluetooth Host Controller

Link Manager

Bluetooth Radio

Bluetooth Baseband

HCIHCIll Host Controller Host Controller

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

Link Layer Control and Link Layer Control and Adaptation ProtocolAdaptation Protocolll Also known as L2CAPAlso known as L2CAPll Basic data link layer protocol over BasebandBasic data link layer protocol over Basebandll Support for:Support for:

–– Protocol MultiplexingProtocol Multiplexing–– Segmentation and Reassembly (SAR)Segmentation and Reassembly (SAR)–– Quality of ServiceQuality of Service–– GroupsGroups

L2CAP ArchitectureL2CAP Architecturell ConnectionConnection--orientedoriented

–– Channel identifier (CID) used to label each connection Channel identifier (CID) used to label each connection endpointendpoint

–– Channels may be uniChannels may be uni--directional or bidirectional or bi--directionaldirectional–– QoS flow specification assigned to each channel directionQoS flow specification assigned to each channel direction

ll ConnectionlessConnectionless–– Supports group abstractionSupports group abstraction

L2CAP ChannelsL2CAP Channels

Device #2

L2CAPCID

Device #4

L2CAPCID

Device #3

L2CAPCID

Device #1

L2CAP CID

Connection-Oriented Data Channel

Connectionless Data Channel

L2CAP Signalling Channel

Service Discovery ProtocolService Discovery Protocolll Bluetooth SDP enables Bluetooth devices to Bluetooth SDP enables Bluetooth devices to

discover the characteristics and capabilities of discover the characteristics and capabilities of other Bluetooth devices within RF proximityother Bluetooth devices within RF proximity

ll Within Bluetooth SDP, a service is:Within Bluetooth SDP, a service is:–– any information, resource, or facility that is provided by (or any information, resource, or facility that is provided by (or

through) one Bluetooth device that is advertised as through) one Bluetooth device that is advertised as available to nearby Bluetooth devicesavailable to nearby Bluetooth devices

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

Service DiscoveryService Discoveryll Two partsTwo parts

–– Service record formatService 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 discoverySession protocol for enabling discovery– Searching for and browsing services

Typical SDP Client/Server Typical SDP Client/Server InteractionsInteractions

Client Server

ServiceSearchRequest(SearchPattern)

ServiceSearchResponse(ServiceRecordHandleList)

ServiceAttributeResponse(AttributeList)

ServiceAttributeRequest(ServiceRecordHandle, AttributeIDList)

SDP ScopeSDP Scopell Many Service Discovery ProtocolsMany Service Discovery Protocols

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

ll Bluetooth SDP focuses on service discovery Bluetooth SDP focuses on service discovery within Bluetooth environmentwithin Bluetooth environment

ll SDP does not compete with other technologies.SDP does not compete with other technologies.

ll SDP compliments them by enabling their use in SDP compliments them by enabling their use in Bluetooth environmentsBluetooth environments

RFCOMMRFCOMMll Supports a large base of legacy applications Supports a large base of legacy applications

using the serial port as the primary using the serial port as the primary communications mechanism.communications mechanism.

ll Reuse GSM TS 07.10 as an existing standard for Reuse GSM TS 07.10 as an existing standard for multiplexing a single physical channel and V.24 multiplexing a single physical channel and V.24 emulation.emulation.

ll Designed to allow multiple “ports” over a single Designed to allow multiple “ports” over a single physical channel between a PC and a GSM physical channel between a PC and a GSM handsethandset

TCS ProtocolTCS Protocol

ll Telephony Control Protocol SpecificationTelephony Control Protocol Specification

Group managementGateway may serve more cordless devicesDistributes group information

Call ControlCall setup and releaseSymmetrical derivative of Q.931

TCS ImpactTCS Impactll Cordless Telephony ExampleCordless Telephony Example

–– Phone moves into range of voice access point and Phone moves into range of voice access point and establishes linkestablishes link

–– Phone link placed into a low power statePhone link placed into a low power state–– Incoming call is broadcast to all phonesIncoming call is broadcast to all phones–– On answer, a voice (SCO) link is setupOn answer, a voice (SCO) link is setup

ll IntercomIntercom–– Supports direct phoneSupports direct phone--toto--phone communicationphone communication

Reuse and RecycleReuse and Recyclell Desire to reuse Desire to reuse IrDAIrDA* applications on mobile * applications on mobile

phones and PCsphones and PCs–– Decision to merge with IrDA’s OBEX (Object Exchange) Decision to merge with IrDA’s OBEX (Object Exchange)

protocol on top of RFCOMM or TCP.protocol on top of RFCOMM or TCP.–– Enables harmonized API across PAN technologiesEnables harmonized API across PAN technologies

ll Interaction with applications on phonesInteraction with applications on phones–– Handset manufacturers have agreed on an application Handset manufacturers have agreed on an application

framework called WAP*.framework called WAP*.–– Bluetooth is treated as a WAP “bearer” in a manner similar Bluetooth is treated as a WAP “bearer” in a manner similar

to GSM.to GSM.–– Reuse “browser” interface on mobile phone.Reuse “browser” interface on mobile phone.

OutlineOutlinell Software goalsSoftware goalsll Protocol ReviewProtocol Reviewll Profile ReviewProfile Reviewll SummarySummary

Interoperability and ProfilesInteroperability and Profilesll Protocols define the communication language Protocols define the communication language

spoken between devicesspoken between devices

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

ll Solution: Mandate the language spoken for a Solution: Mandate the language spoken for a given usage modelgiven usage model

ProfilesProfilesll Represents the default solution for a specific Represents the default solution for a specific

usage modelusage modelll “Vertical slice” through the protocol stack“Vertical slice” through the protocol stackll Basis for interoperability and logo requirementsBasis for interoperability and logo requirementsll Each Bluetooth device supports one or more Each Bluetooth device supports one or more

profilesprofiles

Profiles

Applications

Protocols and ProfilesProtocols and Profiles

RelationshipbetweenProtocolsand Profiles

Profiles in the Bluetooth Profiles in the Bluetooth Specification 1.1Specification 1.1

Generic Access Profile

Service DiscoveryApplication Profile

TCS-BIN-based Profiles

Cordless PhoneProfile

Intercom Profile

Serial Port Profile

Dial-up NetworkingProfile

Fax Profile

Generic Object ExchangeProfile

Headset Profile

LAN Access Profile

File TransferProfile

Object Push Profile

SynchronizationProfile

RFCOMM

Example: Dialup Networking Example: Dialup Networking ProfileProfile

ACL SCOBluetooth Baseband

AT Commands

Software SummarySoftware Summary

ll Protocols defined for communicationProtocols defined for communication

ll Profiles defined to promote interoperabilityProfiles defined to promote interoperability

ll Existing protocols used where possibleExisting protocols used where possible

Introduction to Blue Tooth Wireless Technology

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