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