January 2001

Tom Siep, Texas InstrumentsSlide 1

doc.: IEEE 802.15-01/046r1

Submission

Bluetooth Architecture Presentation

Chatschik Bisdikian

IBM Research

January 2001

Tom Siep, Texas InstrumentsSlide 2

doc.: IEEE 802.15-01/046r1

Submission

Topics

•What does Bluetooth do

•Bluetooth Positioning: PAN, LAN and WAN.

•How does it work: piconets, scatternets, security, protocols, and profiles.

January 2001

Tom Siep, Texas InstrumentsSlide 3

doc.: IEEE 802.15-01/046r1

Submission

What does Bluetooth do for me?

Personal Ad-hoc Personal Ad-hoc ConnectivityConnectivity

Cable Cable ReplacementReplacement

Landline

Data/Voice Data/Voice Access PointsAccess Points

January 2001

Tom Siep, Texas InstrumentsSlide 4

doc.: IEEE 802.15-01/046r1

Submission

Wireless Freedom…

Usage scenarios: Headset

User benefits• Multiple device access • Cordless phone benefits• Hand’s free operation

January 2001

Tom Siep, Texas InstrumentsSlide 5

doc.: IEEE 802.15-01/046r1

Submission

Sharing Common Data…

Usage scenarios: Synchronization

User benefits• Proximity synchronization• Easily maintained database• Common information database

January 2001

Tom Siep, Texas InstrumentsSlide 6

doc.: IEEE 802.15-01/046r1

Submission

PSTN, ISDN,PSTN, ISDN,LAN, WAN, xDSLLAN, WAN, xDSL

Remote Connections...

Usage scenarios: Data access points

User benefits• No more connectors • Easy internet access• Common connection experience

January 2001

Tom Siep, Texas InstrumentsSlide 7

doc.: IEEE 802.15-01/046r1

Submission

Wireless Positioning

Cellular Off-Campus Global

Coverage

Wireless LANOn-campus: Office,

School, Airport, Hotel, Home

Bluetooth

Person Space: Office, Room, Briefcase, Pocket, Car

Short Range/Low Power

Voice AND Data

Low-cost

Small form factor

Many Co-located Nets

Universal Bridge

January 2001

Tom Siep, Texas InstrumentsSlide 8

doc.: IEEE 802.15-01/046r1

Submission

•Operates in the 2.4 GHz band at a data rate of 720Kb/s.

•Uses Frequency Hopping (FH) spread spectrum, which divides the frequency band into a number of channels (2.402 - 2.480 GHz yielding 79 channels).

•Radio transceivers hop from one channel to another in a pseudo-random fashion, determined by the master.

•Supports up to 8 devices in a piconet (1 master and 7 slaves).

•Piconets can combine to form scatternets.

Characteristics

January 2001

Tom Siep, Texas InstrumentsSlide 9

doc.: IEEE 802.15-01/046r1

Submission

•A collection of devices connected in an ad hoc fashion.

•One unit will act as a master and the others as slaves for the duration of the piconet connection.

•Master sets the clock and hopping pattern.

•Each piconet has a unique hopping pattern/ID

•Each master can connect to 7 simultaneous or 200+ inactive (parked) slaves per piconet

What is a Piconet?

M

SS

S

SB

P

P

M=MasterS=Slave

P=ParkedSB=Standby

January 2001

Tom Siep, Texas InstrumentsSlide 10

doc.: IEEE 802.15-01/046r1

Submission

•A Scatternet is the linking of multiple co-located piconets through the sharing of common master or slave devices.

•A device can be both a master and a slave.

•Radios are symmetric (same radio can be master or slave)

•High capacity system, each piconet has maximum capacity (720 Kbps)

What is a Scatternet?

M

M

SS

S

S

P

SB

SB

P

P

M=MasterS=Slave

P=ParkedSB=Standby

January 2001

Tom Siep, Texas InstrumentsSlide 11

doc.: IEEE 802.15-01/046r1

Submission

Bluetooth Architecture

Application Framework and Support

Link Manager and L2CAP

Radio & Baseband

Host Controller Interface

RF

Baseband

AudioLink Manager

L2CAP

Other TCS RFCOMM

Data

SDP

Applications

Con

trol

January 2001

Tom Siep, Texas InstrumentsSlide 12

doc.: IEEE 802.15-01/046r1

Submission

The Bluetooth “lower” layers• Radio (RF)

– The Bluetooth radio front-end• 2.4GHz ISM band; 1Mbps• 1,600hops/sec; 0dBm (1mW) radio (up to 20dBm)

• Baseband (BB)– Piconet/Channel definition– “Low-level” packet definition– Channel sharing

• Link Management (LM)– Definition of link properties

• encryption/authentication• polling intervals set-up• SCO link set-up• low power mode set-up

January 2001

Tom Siep, Texas InstrumentsSlide 13

doc.: IEEE 802.15-01/046r1

Submission

Baseband link types• Polling-based (TDD) packet transmissions

– 1 slot: 0.625msec (max 1600 slots/sec)– master/slave slots (even-/odd-numbered slots)

• Synchronous connection-oriented (SCO) link– “circuit-switched”, periodic single-slot packet assignment– symmetric 64Kbps full-duplex

• Asynchronous connection-less (ACL) link– packet switching– asymmetric bandwidth, variable packet size (1,3, or 5 slots)

– max. 721 kbps (57.6 kbps return channel)– 108.8 - 432.6 kbps (symmetric)

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

M S

M S

January 2001

Tom Siep, Texas InstrumentsSlide 14

doc.: IEEE 802.15-01/046r1

Submission

Security: Key generation and usagePIN

E2

Link Key

Encryption Key

E3

Encryption

Authentication

PIN

E2

Link Key

Encryption Key

E3

User Input(Initialization)

(possibly)PermanentStorage

TemporaryStorage

January 2001

Tom Siep, Texas InstrumentsSlide 15

doc.: IEEE 802.15-01/046r1

Submission

Bluetooth protocols• Host Controller Interface (HCI)

– Provides a common interface between the Bluetooth host and a Bluetooth module• Interfaces in spec 1.0: USB; UART; RS-232

• Link Layer Control & Adaptation (L2CAP)– A simple data link protocol on top of the baseband

• connection-oriented & connectionless• protocol multiplexing• segmentation & reassembly• QoS flow specification per connection (channel)• group abstraction

January 2001

Tom Siep, Texas InstrumentsSlide 16

doc.: IEEE 802.15-01/046r1

Submission

Bluetooth protocols

• Service Discovery Protocol (SDP)– Defines an inquiry/response protocol for discovering services

• RFCOMM (based on GSM TS07.10)– emulates a serial-port to support a large base of legacy (serial-port-

based) applications

• Telephony Control Protocol Spec (TCS)– call control (setup & release)

– group management for gateway serving multiple devices

• Legacy protocol reuse– reuse existing protocols, e.g., IrDA’s OBEX, or WAP for

interacting with applications on phones

January 2001

Tom Siep, Texas InstrumentsSlide 17

doc.: IEEE 802.15-01/046r1

Submission

Profiles

ProfilesP

roto

cols

Applications• Represents default solution for a usage model

• Vertical slice through the protocol stack

• Basis for interoperability and logo requirements

• Each Bluetooth device supports one or more profiles

January 2001

Tom Siep, Texas InstrumentsSlide 18

doc.: IEEE 802.15-01/046r1

Submission

Profiles

Generic Access ProfileService Discovery Application ProfileSerial Port Profile

– Dial-up Networking Profile– Fax Profile– Headset Profile– LAN Access Profile (using PPP)– Generic Object Exchange Profile

• File Transfer Profile• Object Push Profile• Synchronization Profile

TCS_BIN-based profiles– Cordless Telephony Profile– Intercom Profile

January 2001

Tom Siep, Texas InstrumentsSlide 19

doc.: IEEE 802.15-01/046r1

Submission

Summary• Bluetooth is a global, RF-based (ISM band:

2.4GHz), short-range, connectivity solution for portable, personal devices– it is not just a radio, it is an end-to-end solution

• The Bluetooth spec comprises– a HW & SW protocol specification– usage case scenario profiles and interoperability requirements

• IEEE 802.15 is working on standardizing the PHY and MAC layers in Bluetooth

• To learn more: http://www.bluetooth.com

January 2001

Tom Siep, Texas InstrumentsSlide 20

doc.: IEEE 802.15-01/046r1

Submission

Construction of the IEEE Draft Standard

January 2001

Tom Siep, Texas InstrumentsSlide 21

doc.: IEEE 802.15-01/046r1

Submission

What IEEE Project 802 Covers

P hys ica l Laye r(P H Y)

M ed ium A ccess Laye r(M A C )

Log ica l L ink C on tro l(LLC )

P hys ica l

D a ta L ink

N e tw ork

Transpo rt

S ess ion

P resen ta tion

A pp lica tion7

6

5

4

3

2

1

IS O O S ILayers

IE E E 802S tandards

Hardw are

Softw are

Transport Control Protocol (TCP)

Internet Protocol (IP)

X.400 and X.500 EMAIL

January 2001

Tom Siep, Texas InstrumentsSlide 22

doc.: IEEE 802.15-01/046r1

Submission

S tationM gm t

More Detail of IEEE P802 Structure

LLC

M A C

P H Y

1 ) L o g ic a l L in k C o n tro l

2) Medium Access Control

3 ) P H Y s ic a l L a y e r

M A C M gm t

P H Y M gm t

4 ) M e d iu m A c c e s sC o n tro lM a n a g e m e n t

5 ) P H Y s ic a l L a y e r M a n a g e m e n t

SAP

SAP SAP

SA

PS

AP

SAP

Service Access Points

January 2001

Tom Siep, Texas InstrumentsSlide 23

doc.: IEEE 802.15-01/046r1

Submission

How Does That Relate to Bluetooth?A pplica tions

TCP/IP HID RFCOMM

Con

trol

L2CAP

Audio

Link Manager

Baseband

RF

D ata

L2CAP

Audio

Link Manager

Baseband

RF

Bluetooth

M AC_SAP

PHY_SAP

M LM E_PLM E_

SAP

PL

ME

_SA

PM

LM

E_S

AP

Sta

tion

Ma

na

gem

ent

MAC M LM E

PHY PLM E

IEEE

January 2001

Tom Siep, Texas InstrumentsSlide 24

doc.: IEEE 802.15-01/046r1

Submission

Real Structure of Bluetooth Protocol