Transcript 802.11 Architecture - Informatika Unsyiah

6-1. Bluetooth Architecture
Overview
NDSL Lab. CSIE, CGU - 1
Agenda
• Who is Bluetooth?
– History and Background
• What does Bluetooth do for you?
– Usage Model
• What is Bluetooth?
– Compliance, compatibility
• What does Bluetooth do?
– Technical points
• Architectural Overview of Bluetooth
NDSL Lab. CSIE, CGU - 2
Who is Bluetooth?
• Harald Blaatand “Bluetooth” II
• King of Denmark 940-981
– Son of Gorm the Old (King of Denmark) and Thyra
Danebod (daughter of King Ethelred of England)
• This is one of two Runic stones
erected in his capitol city of
Jelling (central Jutland)
• The stone’s inscription (“runes”) say:
 Harald controlled Denmark and
Norway
 Harald thinks “notebooks” and
“cellular phones” should
seamlessly communicate
NDSL Lab. CSIE, CGU - 3
Bluetooth Background
• 1997. - Designed by Ericsson
• 1998.2 - Established the Special interest group (form SIG 1)
Ericsson, Nokia, IBM, Toshiba, Intel
• 1998.5 - Bluetooth Consortium is established formally.
• 1999.7 - Bluetooth v1.0beta
Core Specification and Foundation Profile
• 1999.12 - Lucent、3Com、Motorola、Microsoft (form SIG 2)
• 2001.2 - Bluetooth v1.1
• 2002 – IEEE 802.15 WPAN
IEEE 802.15.1 Wireless Personal Area Networks (Bluetooth)
 IEEE 802.15.2 Coexistence
 IEEE 802.15.3 WPAN Higher Rate
 IEEE 802.15.4 WPAN Low Rate

NDSL Lab. CSIE, CGU - 4
Bluetooth Background
Bluetooth SIG 代表性成員（按產業別分類）
半導體
Fujitsu
HewlettPackard
Hitachi Semi
IBM
Intel
LSI Logic
Mitsubishi
Motorola
NEC
Philsar
PrairieComm
Philips
Samsung
Silicon Wave
TI
Toshiba
…Etc.
電信
Alcatel
AT&T Wireless
British Telecom
Daewoo Telecom
Ericsson
France Telecom
Hitachi
LG Telecom
Motorola
Nokia
NTT DoKoMo
Taiwan Telcom
Symbian
Sprint PCS
Qualcomm
電腦與周邊 消費性電子
Acer
Canon
Compaq
Dell Computer
Gateway 200
Hitachi
IBM
NCR
NEC
Palm
Ricoh
Seiko Epson
Canon
Casio
Fuji Photo
Hitachi
LG Electronics
Nokia
Philips
Radio Shack
Samsung
Sanyo
Sharp
Sony
Toshiba
網路
3Com
Broadcom
Harris
Hitachi
Intel
Lucent
Nortel
Networks
Siemens AG
Xircom
汽車和其他
BMW
British Airways
Federal Express
Ford
Harris
Saab
Tektronix
Thomson
Tokyo Gas Co.
Volvo
資料來源：Bluetooth SIG，2000 年 1 月
NDSL Lab. CSIE, CGU - 5
What does Bluetooth do for you?
 three major applications
Landline
Cable
Replacement
Data/Voice
Access Points
(internet access)
most important in
voice applications
Personal Ad-hoc Networks
NDSL Lab. CSIE, CGU - 6
Usage Model (Ultimate Headset)
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Usage Model (Ultimate Headset)
• Keep your hands free for
– Car
– Office
– Road
NDSL Lab. CSIE, CGU - 8
Usage Model (Automatic Synchronizer)
• Background Synchronization
– PDA
– Cellular Phone
– Notebook
NDSL Lab. CSIE, CGU - 9
Usage Model (Three in One Phone)
• Intercom (Walki Talki)
• Cordless
• Cellular
NDSL Lab. CSIE, CGU - 10
Usage Model (Three in One Phone)
• Office (No telephone charge)
• Home (Fixed line charge)
• Outdoor (Mobile phone charge)
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Usage Model (Remote Control &Transmission)
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Usage Model (Conference Scenario)
• Conference Table
– Share and exchange data
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Usage Model (killer application)
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Key Characteristics
• Low cost
– Market consideration
• Low power consumption
– Portable device consideration
– Short Range
• Unlicensed Used
– ISM band used
• Robust operation
– Fast frequency hopping
– Short packet length
• Multiple links
• Mixed voice and data
• Sized 0.5 squire inches
NDSL Lab. CSIE, CGU - 15
Mobile = Battery life
• Low power consumption*
–
–
–
Standby current < 0.3 mA
3 months
Voice mode 8-30 mA
75 hours
Data mode average 5 mA
(0.3-30mA, 20 kbit/s, 25%)
120 hours
• Low Power Architecture
–
–
Programmable data length (else radio sleeps)
Hold and Park modes 60 µA (rough)
»
Devices connected but not participating
»
Hold retains AMA address, Park releases AMA, gets
PMA address
»
Device can participate within 2 ms
NDSL Lab. CSIE, CGU - 16
Bluetooth Specifications
Applications
IP
SDP
RFCOMM
Applications
Data
Audio
L2CAP
Link Manager
Baseband
RF
Firmware
Bluetooth chip
(Single chip with RS-232,
USB or PC card interface)
NDSL Lab. CSIE, CGU - 17
Bluetooth Certifications
T e c h n o l o g y
Certification
T e c h n o l o g y
Certification Application Framework
Layer
Certification Classes
Application
Framework
Certification
Applications
vCard
vCal
IP
SDP
vCard
vCal
PPP
IrOBEX
Data
Audio
Ctrl
Audio
Ctrl
Audio
UDP
RFCOMM
IrOBEX
PPP
WAP
TS0710
TS0710
L2CAP
A
U
D
IA
OU
D
I
O
WAP
TCP/IP
TCP/IP
L2CAP
Application
Framework Certification Class
Lower Interface
Class
Layer Certification
Classes
Service
vCard
vCal
Service
UDP
PPP
vCard
IrOBEX
vCal
WAP
UDP
Still
Images
PPP
Type
IrOBEX
IrOBEX
PPP
Type
RFCOMM
IrOBEX
RFCOMM
IrOBEX
TCP/IP
PPP
HID
RFCOMM
IrOBEX
Audio
WAPCtrl
RFCOMM
Still Images
TCP/IP
HID
Audio Ctrl
RFCOMM
L2TCP/IP
CAP
L2CAP
2 HID
L CAP
2
L2LCAP
CAP
RFCOMM
TCP/IP
HID
L CAP
L2CAP
L2CAP
UDP
Still
Img
Still
Img
HID
HID
2
BT.OBEX
BT.OBEX
Lower Interface
BT.PPP
Class
BT.TS0710
BT.OBEX
BT.TS0710
BT.OBEX
BT.TCP/IP
BT.PPP
BT.HID
BT.TS0710
BT.TS0710
2
BT.L
CAP-A
BT.TCP/IP
2
BT.L
CAP-D
BT.HID
2
BT.L CAP-D
2
2
BT.L
BT.LCAP-D
CAP-A
BT.OBEX
BT.AudioCtrl
BT.WAP
BT.TS0710
BT.SImg
BT.TCP/IP
BT.HID
BT.AudioCtrl
BT.L CAP-D
BT.L2CAP-D
BT.L2CAP-D
BT.TS0710
BT.TCP/IP
BT.HID
2
Basic Layer Certification Classes
Service Host Controller Interface
HCI:
Lower Interface
Link Manager
BB
LM
RF BB
RF
Certification Class
Type
Class
Basic
Layer
Classes
Audio Certification
Data
Audio
2CAP
LLM
Baseband
RF
BT.vCard
BT.vCal Class
Certification
BT.UDP
BT.PPP
BT.vCard
BT.OBEX
BT.vCal
BT.WAP
BT.UDP
BT.SImg
BT.PPP
2
L CAP
LM
BT.LM-A
Lower
Interface BT.LM-D
Service
LM
BB
BT.BB-A Class
BT.BB-D
Type
BB
RF
BT.RF
BT.RF
Audio
Data
RF2
Air
L
CAP
LM
BT.LM-A
BT.LM-D
A unit that supports both audio and data gets the certification class A and D.
LM
BB
BT.BB-A
BT.BB-D
Example: BT.BB-A,D
BB
RF
BT.RF
BT.RF
RF
Air
-
Data
2
2
BT.L CAP-A
BT.L
CAP-D
Certification
Class
BT.LM-A
BT.LM-D
BT.BB-A
BT.BB-D
Audio
Data
BT.RF
BT.RF
2
2
BT.L CAP-A
BT.L CAP-D
BT.LM-A
BT.LM-D
BT.BB-A
BT.BB-D
BT.RF
BT.RF
A unit that supports both audio and data gets the certification class A and D.
Example: BT.BB-A,D
Basic Layer Certification
NDSL Lab. CSIE, CGU - 18
Host Control Interface (HCI) (1/3)
Program
Profile Spec
Audio
L2CAP
Host
HCI (Host control Interface)
HCI (Host control Interface)
Audio
LMP
Bluetooth chip
Baseband
RF
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Bluetooth Host
HCI (2/3)
Host Drives and Applications
Bluetooth HCI driver
Bluetooth HCI Transport driver
(USB, PC Card, PCI)
HCI
HCI : Host Controller Interface
provides a common interface
between the bluetooth host
and the bluetooth module.
Transport Bus
HCI Transport Firmware
Bluetooth Host Controller
Link Manager
Bluetooth Baseband
Bluetooth Radio
Bluetooth Module
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HCI (3/3)
– All HCI transactions are
framed in packets:
– Commands
– Event
– Data (ACL)
– Data (SCO)
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Bluetooth Products
• Blue-Dongle
• Blue-Connect
• BluePort
• Bluetooth printer
• Bluetooth Modem
• Etc.,
NDSL Lab. CSIE, CGU - 22
BT Trend (1/2)
• 2 chips solution
– RF transceiver
– Baseband BB chip
• integrated single chip (BB+RF) solution will
be provided
• Chip design house co-work with software
design company to provide total solution of
bluetooth technology
NDSL Lab. CSIE, CGU - 23
BT Trend (2/2)
Cost
$30
BB
RF
2-chip
Headset
Version
$10
BB+RF
Full Bluetooth
Performance
2000
Single-chip
Data Only
Version
2001
$4
Host+BB+RF
Single-chip
2003
?
Soft. modem
Host+RF
Year
NDSL Lab. CSIE, CGU - 24
Bluetooth Module
• CPU core : ARM, 8051, MIPS, etc.,
HOST
RF
Transceiver
NDSL Lab. CSIE, CGU - 25
Bluetooth Module
• Software modem is possible nowaday
HOST
NDSL Lab. CSIE, CGU - 26
RF Transceiver
NDSL Lab. CSIE, CGU - 27
Bluetooth Specifications
• 2.4 GHz ISM Unlicensed band
• Microwave ovens also use this band
• Frequency Hopping Spread Spectrum
–
–
–
–
–
Avoid interference
23/79 channels
1 MHz per channel
1 Mbps link rate (GFSK modulation)
Fast frequency hopping and short data packets avoids
interference
» Nominally hops at 1600 times a second (vs. 2.5 hops/sec in IEEE
802.11)
» 625us per hop (366us for data only)
» 3200 times a second during inquiry and paging modes
• Multiple uncoordinated networks may exist and cause
interference
– CVSD (Continuous Variable Slope Delta Modulation) voice
coding (FEC) enables operation at high bit error rates
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ISM Unlicensed Band
• 79 channels in 2.4GHz (in USA and most Europe)
Guard band
Licensed
band
Guard band
2.402-2.480 GHz
79 hopping channels
2.4 2.402
GHz
Licensed
band
2.48
2.483
ISM unlicensed band
NDSL Lab. CSIE, CGU - 29
Frequency Range
• 2.4GHz ISM Frequency Range
Country
Europe* & USA
Japan
Spain
France
Frequency Range
2400 – 2483.5 MHz
2471 – 2497 MHz
2445 – 2475 MHz
2446.5 – 2483.5 MHz
RF Channels
f=2402 + k MHz
f=2473 + k MHz
f=2449 + k MHz
f=2454 + k MHz
k=0,…,78
k=0,…,22
k=0,…,22
k=0,…,22
1MHz
. . .
79
12 3
83.5 MHz
NDSL Lab. CSIE, CGU - 30
Transmit Power
• transmit power and range
 0 dbm (up to 20dbm with power control)
 10-100 m
Power
Class
1
2
3

Max Output
100mW
(20dBm)
2.5mW
(4dBm)
1mW
(0dBm)
Min
Output
1mW
(0dB)
0.25mW
(-6dBm)
N/A
Power
Control
-4db/time
Max twice
Optional
Optional
Power 1mW (class 3)
•3% power of cellular phone
•10meters of transmission distance or 100m by PA

Power 100mW(class 1)
•100 meters of transmission distance
NDSL Lab. CSIE, CGU - 31
Frequency Hopping
78
Frequency
0
Time
NDSL Lab. CSIE, CGU - 32
FHSS
Data
Source
Transmitter
d(t)
Digital
Modulator
Hopping
Code
Generator
Front-end
Filter
+
Frequency
synthesizer
+
Data
Detector
^
d(t)
Receiver
Local hopping
code generator
Frequency
synthesizer
NDSL Lab. CSIE, CGU - 33
Modulation and Symbol Rate
• Symbol Rate : 1M symbols/sec (1MHz)
• GFSK (Gaussian Frequency Shift Keying)
– Binary One (1) : Positive frequency deviation
– Binary Zero (0) : Negative frequency deviation
• Maximum frequency deviation
– Between 140kHz and 175kHz
Magnitude
frequency
fo-f
fo
fo+f
NDSL Lab. CSIE, CGU - 34
Adaptive Frequency Hopping
• When no interference is detected, hop
over the entire frequency band
• If interference is detected at a level which
cause packet error
– Actively avoid these frequency hop locations.
– This technique is currently legal for Class 3
Bluetooth units.
– Hop locations must be maintained
NDSL Lab. CSIE, CGU - 35
Interference Simulations
– 1 Bluetooth piconet + 1 WLAN unit
– PER (Packet Error Rate) without adaptation =11%
– PER with adaptation = 0%
– 5 Bluetooth piconets separated by 5 meters + 1
WLAN unit
– PER without adaptation =15%
– PER with adaptation = 8.4%
NDSL Lab. CSIE, CGU - 36
Radio 2 WG
• Radio 2 WG mandated to be backward
compatible and interoperable with Radio 1
– 5.8G ISM band
– is optional extensions for providing additional
capabilities for applications
– Higher data rates:
•
•
•
•
Multimedia (streaming audio/video)
High speed image transfer
High speed transfer of large files to (e.g.) printers
Data rate alignment with 2.5/3G cellar networks
– 10M-12Mbps goal
NDSL Lab. CSIE, CGU - 37
Network Topology
•
Radio Designation
– Connected radios can be master
or slave
– Radios are symmetric (same
radio can be master or slave)
•
Piconet
– Master can connect to 7
simultaneous or 200+ active
slaves per piconet
– Each piconet has maximum
capacity (1 Msps and 1 Mbps)
S
P
M
sb
M
P
S
P
sb
S
S
» Unique hopping pattern/ID
•
Scatternet
– High capacity system
» Minimal impact with up to 10
piconets within range
–
Radios can share piconets!
NDSL Lab. CSIE, CGU - 38
Piconet vs. Scatternet
• A scatternet contains two piconets
Piconet
Scatternet
Slave
Master
Master
Piconet
Slave Slave
Slave
Slave
NDSL Lab. CSIE, CGU - 39
Piconet and Scatternet
point-to-point
(piconet)
multi-point
(piconet)
scatternet
Master host
Slave host
NDSL Lab. CSIE, CGU - 40
Device Addressing (1/2)
• Every Bluetooth device has unique 48-bit Bluetooth Device
Address (BD_ADDR) which is assigned by SIG
• The BD_ADDR is used to control the system functions :
– Hopping sequence
– Channel access code
– Encryption key
• The BD_ADDR contains 3 parts:
– 24-bit Lower Address Part (LAP)
» Used to identify unique BT device (reduce overhead)
– 8-bit Upper Address Part (UAP)
» Used to determine the hopping sequence
– 16-bit Non-significant Address Part (NAP)
BD_ADDR
16
8
24
NAP
UAP
LAP
bits
NDSL Lab. CSIE, CGU - 41
Device Addressing (2/2)
• AM_ADDR (Active Member Address)
– Each slave is assigned a 3-bit address
– 7 slaves in a piconet is available
– 000 : for broadcasting packets (I.e. master address)
» An exception is FHS (Frequency Hopping Synchronization) packet
which may use “000” address but is not a broadcast message
– Slaves that are disconnected or parked give up their
AM_ADDRs
• PM_ADDR (Parked Member Address)
– Slaves that enter the park mode will obtain a 8-bit PM_ADDR
– At most 256 slaves are in park mode in a piconet
NDSL Lab. CSIE, CGU - 42
Clock Synchronization
• CLKN (Native Clock)
– Exist in each bluetooth device
– The counter can not be frozen and adjusted
– Clock resolution : 312.5us (half slot time : used for
paging/inquiry procedures)
– slave follows its master CLKN to hop in a piconet
» Master need inform the slave its CLKN and BD_ADDR
» Slave adds offset into its CLKN to synchronize with master
Slave
Native CLK
+
Master clock
BD_ADDR
same hopping sequence
3, 56, 7, 23, 44, …
offset
Master
BD_ADDR
NDSL Lab. CSIE, CGU - 43
Clock Synchronization
• CLKE (Estimated Clock)
– Is used when master pages a known slave device (has
been inquired)
– Master uses the slave’s BD_ADDR to estimate the
slave’s CLKN
Slave
CLKE
paging
+
Slave clock
BD_ADDR
estimated slave’s
hopping sequence
3, 56, 7, 23, 44, …
Slave
BD_ADDR
NDSL Lab. CSIE, CGU - 44
IDa
The Piconet
IDd
IDa
IDd
D
IDa
A
P
M
IDe
IDe
E
sb
IDa
IDb
B
IDb
IDc
S
C
IDa
IDc
S
• All devices in a piconet hop together
– In forming a piconet, master gives slaves its clock and device ID
(BD_ADDR) via FHS packet
» Hopping pattern determined by device ID (48-bit)
» Phase in hopping pattern determined by Clock
• Non-piconet devices are in standby
• Piconet Addressing
– Active Member Address (AMA, 3-bits)
– Parked Member Address (PMA, 8-bits)
IDa
sb
M
or
S
P
NDSL Lab. CSIE, CGU - 45
Basic Baseband Protocol
Frame
Frame (1.25 ms)
fk
Master
Master
One
Slot
Packet
One
Slot
Packet
Slave
fk
fk+1
fk+1
Three Slot Packet
One
Slot
Packet
Slave
625 us
One Slot
625 us
One Slot
• Spread spectrum frequency hopping radio
– Hops every packet
» Packets are 1, 3 or 5 slots long
– Frame consists of two packets
» Transmit followed by receive
– Nominally hops at 1600 times a second (1 slot
packets)
NDSL Lab. CSIE, CGU - 46
Time Division Duplex (TDD)
• Master : even numbered slots
• Slave : odd numbered slots
• The Slot Number ranges from 0- 227-1.
f(2k)
f(2k+1)
f(2k+2)
Master
+/-10 s
220 s
Slave
guard
time
even (625s)
Access code/Header
Packet
odd (625s)
Payload
even
time
slot
guard time for hopping
NDSL Lab. CSIE, CGU - 47
Multi-slot Packets
• Different packet overhead will result in different throughput
– DH1 : 172.8Kbps in Sym. and Asyn. modes
– DH3 : 390.4Kbps in Sym. mode; 387.2 and 54.4Kbps in Asyn.
Mode
– DH5 : 433.9Kbps in Sym. mode; 721 and 57.6Kbps in Aysn.
» DH : without FEC
1-slot
Packet
(DH1)
f(2k)
f(2k+1)
f(2k+2)
f(2k+3)
f(2k+4)
3-slot
Packet
(DH3)
f(2k)
f(2k+1)
f(2k+2)
f(2k+3)
f(2k+4)
5-slot
Packet
(DH5)
f(2k)
f(2k+1)
f(2k+2)
f(2k+3)
f(2k+4)
even (625s) odd (625s) even (625s) odd (625s)
NDSL Lab. CSIE, CGU - 48
Connection Procedure (1/3)
•
Standby
– Waiting to join a piconet
•
Inquire
– Ask about radios to
connect to
•
Page
– Connect to a specific radio
•
Connected
– Actively on a piconet
(master or slave)
•
Park/Sniff/Hold
– Low Power connected
states
NDSL Lab. CSIE, CGU - 49
Connection Procedure (2/3)
ID packet
FHS packet
ID packet
ID : GIAC/DIAC
FHS : slave’s BD_ADDR,
CLKN, Class of Devise(CoD),
Page Scan Interval
ID : DIAC
ID packet
FHS packet
Data packet
FHS : master’s BD_ADDR,
CLKN, CoD, BCH parity, AMA
NDSL Lab. CSIE, CGU - 50
ID Packet
• Access Code
34bits
24bits
BCH Parity
Word
LAP
24 bits
6bits
Barker
Sequence
• During a connection
– identifies the packet as being from or to a specific Master
• Other modes
– in inquiry to produce the Inquiry Access Code (IAC)
NDSL Lab. CSIE, CGU - 51
FHS Packet Format
•
Used when
1. Master inquiries device during inquiry procedure, return from
Slave
2. Master pages a Slave during page procedure, sent from
Master
3. A device switches as Master
NDSL Lab. CSIE, CGU - 52
Connection Procedure (3/3)
Unconnected
Standby
tac
h
Standby
De
Ttypical=2s
Connecting
States
Inquiry
Page
Ttypical=0.6s
Active
States
Transmit
data
AMA
Connected
AMA
Ttypical=2 ms
Low Power
States
Releases
AMA
Address
PARK
PMA
Ttypical=2 ms
HOLD
AMA
NDSL Lab. CSIE, CGU - 53
Page and Inquire Scans
Ttypical=11 ms
18 slots
Ttypical=11 ms
18 slots
Page Scan
Page Scan
Sleep
Connected
Ttypical=1.25
Ttypical=1.25
Inquire
Scan
Inquire
Scan
Standby
Connected
Ttypical=11 ms
18 slots
Ttypical=11 ms
18 slots
• A radio must be enabled to accept pages or inquires
– Consumes 18 slots every 1.25 s (or so) for each scan
 slot is 0.625 ms
NDSL Lab. CSIE, CGU - 54
Page and Inquire Scans
• Inquiry scan:
– 32 channels (of 79 channels) are assigned for inquiry
procedure
– 32 channels are divided as 2 trains (Trains A and B), each one
contains 16 channels.
• Page scan:
– 32 channels (of 79 channels) are assigned for page procedure
– 32 channels are divided as 2 trains (Trains A and B), each one
contains 16 adjacent channels.
– Train A : f(k-8), f(k-7), … f(k), f(k+1), … , f(k+7)
– Train B : f(k-16), f(k-15), … f(k-9), f(k+8), … , f(k+15)
• 3200 hop/sec
• Broadcast ID packet (with specified GIAC or DIAC)
NDSL Lab. CSIE, CGU - 55
Inquiring for Radios
IDd
IDa
D
A
IDb
B
IDc
C
• Radio wants to find other radios in the area
NDSL Lab. CSIE, CGU - 56
Inquiring for Radios
IDd
IDa
D
INQ
A
INQ
IDb
Inquire
INQ
B
IDc
C
• Radio Wants to find other radios in the area
– Radio A issues an Inquire (pages with the Inquire ID)
» Radios B, C and D are doing an Inquire Scan
NDSL Lab. CSIE, CGU - 57
Inquiring for Radios
IDd
IDa
D
A
IDb
IDb
B
IDc
C
• Radio Wants to find other radios in the area
– Radio A issues an Inquire (pages with the Inquire ID)
» Radios B, C and D are doing a Inquire Scan
– Radio B recognizes Inquire and responds with an FHS
packet
» Has slave’s Device ID and Clock
NDSL Lab. CSIE, CGU - 58
Inquiring for Radios
IDd
IDb
IDa
D
INQ
A
INQ
IDb
Inquire
INQ
B
IDc
C
• Radio Wants to find other radios in the area
– Radio A issues an Inquire (pages with the Inquire ID)
» Radios B, C and D are doing a Inquire Scan
– Radio B recognizes Inquire and responds with an FHS
packet
» Has slave’s Device ID and Clock
NDSL Lab. CSIE, CGU - 59
Inquiring for Radios
IDd
IDb
IDa
IDd
D
A
IDc
IDb
B
IDc
C
• Radio Wants to find other radios in the area
– Radio A Issues an Inquire (again)
– Radios C and D respond with FHS packets
» As radios C & D respond simultaneously packets are
corrupted and Radio A won’t respond
» Each radio waits a random number of slots and listens
NDSL Lab. CSIE, CGU - 60
Inquiring for Radios
IDd
IDb
IDa
D
INQ
A
INQ
IDb
Inquire
INQ
B
IDc
C
• Radio Wants to find other radios in the area
– Radio A Issues an Inquire (again)
NDSL Lab. CSIE, CGU - 61
Inquiring for Radios
IDd
IDb
IDa
D
A
IDc
IDb
B
IDc
C
• Radio Wants to find other radios in the area
– Radio A Issues an Inquire (again)
– Radios C respond with FHS packets
NDSL Lab. CSIE, CGU - 62
Inquiring for Radios
IDd
IDb
IDa
IDc
D
INQ
A
INQ
IDb
Inquire
INQ
B
IDc
C
• Radio Wants to find other radios in the area
– Radio A Issues an Inquire (again)
NDSL Lab. CSIE, CGU - 63
Inquiring for Radios
IDd
IDb
IDa
IDc
IDd
D
A
IDb
B
IDc
C
• Radio Wants to find other radios in the area
– Radio A Issues an Inquire (again)
– Radios D respond with FHS packets
NDSL Lab. CSIE, CGU - 64
Inquiring for Radios
IDd
IDb
IDa
IDc
D
A
IDd
IDb
B
IDc
C
• Radio Wants to find other radios in the area
– Radio A Issues an Inquire (again)
– Radios D respond with FHS packets
– Radio A now has information of all radios within range
NDSL Lab. CSIE, CGU - 65
Inquiry Procedure
fk
fk+1
fk
fk+1
fk+4
IDa
INQUIRER
INQ
INQ
IDb
INQ
fk+1
IDb
STANDBY
FHS
625 s
• Inquiry has unique device address (all BT radio use)
– ID packet with dedicated or general access code
– Unique set of “Inquiry” hop frequencies
• Any device can inquire by paging the Inquiry address
• Correlater hit causes slave to respond with FHS packet
– Device ID
– Clock
– Etc.
NDSL Lab. CSIE, CGU - 66
Inquiry Procedure
1.25ms
Fully scan Train A:16*0.625ms=10ms
(1) Train A will be scanned 256 times: 2.56s
(2) Train B will be scanned 256 times: 2.56s
Repeat scan Trains A and B two complete cycles:
2*(2.56+2.56)=10.24s
2 slots
1
2
3
15
16
repeat 256 times
INQUIRER
train
A
A
A
A
A
B
A
A
A
10 ms
16 slots = 10ms
STANDBY
scan fk
A
sleep RAND1
fk
fk+1
A
A
fk+1
sleep RAND2
fk+2
A
FHS
A
FHS
Listen 11.25 ms (18 slots)
•
32 channels are allocated as inquiry procedure
– They are divided as two trains : A Train and B Train (16 channels for each)
•
Multiple slaves are expected to respond
– Correlater hit causes slave to
» respond with FHS packet
» Wait a random number of slots
» Wait for another Inquiry page and repeat
•
Master should end up with a list of slave FHS packets in area
NDSL Lab. CSIE, CGU - 67
Inquire Summary
• Inquiring radio Issues inquiry packet with Inquire
ID (GIAC or DIAC access code)
• Any radio doing an Inquire scan will respond with
an FHS packet
– FHS packet gives Inquiring radio information to page
» Device ID
» Clock
IDa
– If there is a collision then radios wait a random number
of slots before responding to the page inquire
• After process is done, Inquiring radio has Device
IDs and Clocks of all radios in range
• Slave listens one of 16 channels for sufficient
time (e.g., 18 slots=11.25ms)
NDSL Lab. CSIE, CGU - 68
Master Paging a Slave
IDa
IDc
A
IDc
C
• Paging assumes master has slaves Device ID and
an idea of its Clock
NDSL Lab. CSIE, CGU - 69
Master Paging a Slave
IDa
IDc
A
Page
IDc
IDc
C
• Paging assumes master has slaves Device ID and
an idea of its Clock
– A pages C with C’s Device ID and CLKE
NDSL Lab. CSIE, CGU - 70
Master Paging a Slave
IDa
IDc
A
IDc
IDc
C
• Paging assumes master has slaves Device ID and
an idea of its Clock
– A pages C with C’s Device ID (DAC)
– C Replies to A with C’s Device ID
NDSL Lab. CSIE, CGU - 71
Master Paging a Slave
IDa
IDc
A
IDa
IDc
C
• Paging assumes master has slaves Device ID and
an idea of its Clock
– A pages C with C’s Device ID
– C Replies to A with C’s Device ID
– A sends C its Device ID and Clock (FHS packet)
NDSL Lab. CSIE, CGU - 72
Master Paging a Slave
IDa
IDc
A
IDa
IDc
C
• Paging assumes master has slaves Device ID and
an idea of its Clock
–
–
–
–
A pages C with C’s Device ID
C Replies to A with C’s Device ID
A sends C its Device ID and Clock (FHS packet)
A connects as a master to C
NDSL Lab. CSIE, CGU - 73
Master Paging a slave
fk
fk+1
fk
fk+1
fk+2
fk+2
fm
FH
S
Master
IDa
IDc
IDc
IDc
IDa
IDc
fk+1
Slave
IDc
625 s
•
Master pages slave (packet has slave ID) at slave page frequency (1 of 32)
–
Master sends page train of 16 most likely frequencies in slave hop set
» Slave ID sent twice a transmit slot on slave page frequency
» Master listens twice at receive slot for a response
–
•
If misses, master sends second train on remaining 16 frequencies
Slave listens for 11.25 ms (page scan)
–
–
–
If correlater triggers, slave wakes-up and relays packet at response frequency
Master responds with FHS packet (provides master’s Device ID and Clock)
Slave joins piconet
NDSL Lab. CSIE, CGU - 74
Paging Procedure
1.25ms
FHS
Pager
train
A
A
A
A
B
B
10 ms
Paged
CONNECTION
scan fk
B
Sleep (1.25 s)
fk+1
B
11.25 ms
• Each slave page scans on unique sequence of 32
channels fk
– Master pages 16 most likely channels for entire sleep
period (nominally 1.25 seconds)
• If clocks are off, then second train sent on last 16
frequencies for entire sleep period
NDSL Lab. CSIE, CGU - 75
Physical Link Definition
• SYNCHRONOUS CONNECTIONORIENTED (SCO) LINK
•
•
•
•
•
•
circuit switching
symmetric, synchronous services
slot reservation at fixed intervals
For voice transmission
Point-to-point connection
No packet retransmission
• ASYNCHRONOUS CONNECTIONLESS (ACL) LINK
•
•
•
•
•
•
packet switching
(a)symmetric, asynchronous services
polling access scheme
For data transmission (ex:program)
Point-to-multipoint connection
Packet retransmission
NDSL Lab. CSIE, CGU - 76
Physical Link
HV3 : 6 slots gap
NDSL Lab. CSIE, CGU - 77
Packet Types/Data Rates
Packet Types
SEGMENT
1
2
TYPE
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
SCO
link
ACL
link
NULL
POLL
FHS
DM1
NULL
POLL
FHS
DM1
DM1
108.8
108.8
108.8
DH1
172.8
172.8
172.8
DH1
DM3
258.1
387.2
54.4
DH3
390.4
585.6
86.4
DM5
286.7
477.8
36.3
DH5
432.6
721.0
57.6
HV1
HV2
HV3
DV
Data Rates (Kbps)
TYPE
symmetric
asymmetric
AUX1
3
1010
1011
1100
1101
DM3
DH3
4
1110
1111
DM5
DH5
NDSL Lab. CSIE, CGU - 78
Bluetooth Protocols
Still Image
WAE
vCard/vCal
WAP
OBEX
HID
Service Discovery
TCP/UDP
Audio
Printing
RFCOMM
IP
TCS
L2CAP
Host Controller Interface
NDSL Lab. CSIE, CGU - 79
THANK YOU
Q&A
NDSL Lab. CSIE, CGU - 80