®

www.xilinx.com

Host Controller Interface

Inside Bluetooth

RF (radio and antenna)

Audi

o (S

CO)

Cont

rol

Audi

o(S

CO)

Con

trol

L2CAP

BasebandLink Manager

Transport Interface

ApplicationRFCOMM SDP

Data (ACL)

Data (ACL)Host

Blue

toot

hM

odul

e

Transport Bus

Host Application

API and Legacy Support Modules

Bluetooth HCI Driver

Physical I/F

Physical I/F

HCI Firmware

Logical Link Control & Data Adaptation

Physical Link Control

Data Processing & Transmission Mgmt.

Transmission/Reception

®

www.xilinx.com

L2CAP Logical Link Control and Adaptation Protocol

w Manages the creation and termination of virtualconnections with other Bluetooth devices— Negotiates and/or dictates parameters

– Including Security and Quality of Service (QoS)

w Manages ACL data flow between the host and LinkManager— Multiplixing of multiple concurrent host I/O operations— Segmentation And Reassembly (SAR) of various data

formats for baseband compatibility

®

www.xilinx.com

Link Manager

w Physically manages creation, configuration, andtermination of device to device links

w Also manages ACL data flow between the L2CAPand Baseband through established links— Forwards data from the L2CAP to the Baseband with

its associated link specific transmission parameters— Forwards data from the Baseband back to the L2CAP

associated to its specific source link

®

www.xilinx.com

Baseband

w Performs all digital data processing operations— Speech coding— Data whitening— Optional encryption/decryption— Packetization— Header and payload error detection and correction

w Calculates and controls transmission frequency— Supporting Bluetooth’s 80 channel Frequency

Hopping (FH) spread spectrum transmission method

®

www.xilinx.com

How Does Bluetooth Work?

Master

Active Slave

Parked Slave*

Standby*

N

J

F

IC

D

M

OP

Q

Operational States

* Low power state

®

www.xilinx.com

In the Beginningw Initially Bluetooth devices only know about themselves

— Everyone passively monitors in Standby mode— No devices are synchronized

D

A

E

B

C

F

KJ

H G

I

MN

L

PO

Q

®

www.xilinx.com

InquiryDiscovering Who’s Out There

D

A

w Inquiry discovers what other devices within range

10 meters

H MN

L

PO

Q

B

C

F

KJ

G

I

E

H

®

www.xilinx.com

D

E

F H G

I

KJ

PagingCreating a Piconet

w Paging creates a Master/Slave link called a Piconet

C

MN

L

PO

Q

BBAA

10 meters

®

www.xilinx.com

D

Expanding a Piconet (1)w Successive Pages can attach up to 7 Active Slaves to a

Piconet at one time

H

B

C

MN

L

PO

Q

E

FG

IJ

F

JI

E

G

KK

A

10 meters

®

www.xilinx.com

BB

JJ

DH

K

F

I

E

G

Parkingw To save power and/or to connect to even more devices

Active Slaves can be Parked (up to 256 total!)

C

MN

L

PO

Q

A

10 meters

®

www.xilinx.com

D

K

F

I

E

G

Expanding a Piconet (2)w Masters can then attach additional Active Slaves using

Active Member Addresses freed up through Parking

B

J

MN

L

PO

Q

H

C

H

C

A

10 meters

®

www.xilinx.com

J

F

I

E

A

G

Scatternets

D

M

O

w Bluetooth devices can participate in multiple Piconetssimultaneously creating a topologies called Scatternets

B

L

H

K

C

N

P

Q

®

www.xilinx.com

NH

K

F

I

E

A

G

J

C

Advanced Scatternets

D

M

O

w Scatternets can evolve into extremely complex structurescreating a rich fabric of many, many, devices

P

Q

B

L

®

www.xilinx.com

Bluetooth Radio Basics

w Normal range: 10 meters

w Normal xmit power: 1 milliWatt

w Receiver sensitivity: -70 dB

w Frequency band: 2.4 GHz(ISM)

w Max data rate: 721Kbps + 56Kbps X 3 (voice)

®

www.xilinx.com

Bluetooth Radio Frequency Band

w ISM (Industrial, Scientific, Medical) band— 2.402GHz - 2.480GHz (79MHz total bandwidth)

w Advantages— Free— Open to everyone worldwide

w Disadvantages— Noise sources from everywhere

– Cordless phones, microwave ovens, garage door openers,other wireless LAN technologies, baby monitors,...

®

www.xilinx.com

Bluetooth’s Noise Solutions

w Frequency Hopping (FH) Spread Spectrumtechnology— Divides the band into 79 separate 1MHz channels

w Uses short packets and makes 1600 hops/second— Minimizes exposure to noisy channels— Enables bad voice packets to be discarded

w Forward Error Correction (FEC) of data packets— Data often recoverable even on a noisy channel

without retransmission

®

www.xilinx.com

Bluetooth Transmission ProtocolFrequency Hopping & Time Division Duplexing

fk+2

625 µsSlot 3

fk+3

Frame 2

Slot4

t

w Frequency hops from Slot to Slot to Slotw Frames define matched Master / Slave Slot transmissions

fk+1

Frame 1

Slot2

w Complete packet transmission occurs during a Slot

Master

Slave1

fk

625 µsSlot 1

®

www.xilinx.com

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

Piconet A Contention

Total Transmission Slots: 100 Transmission Slots Hit: 0 Transmission Efficiency: ~100%Active Piconets: 1

Frequency HoppingGraphically Illustrated

Transmission Channel (1 - 79)

Transmission Slot (time)

Each channel can carry a separateBluetooth transmission without contention

®

www.xilinx.com

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

Piconet A Contention

Total Transmission Slots: 100 Transmission Slots Hit: 0 Transmission Efficiency: ~100%Active Piconets: 1

Each Bluetooth Piconet RandomlyChanges Frequency Slot by Slot by Slot

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

Piconet A Contention

Total Transmission Slots: 100 Transmission Slots Hit: 0 Transmission Efficiency: ~100%Active Piconets: 1

®

www.xilinx.com

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

Piconet A Contention

Total Transmission Slots: 100 Transmission Slots Hit: 0 Transmission Efficiency: ~100%Active Piconets: 1

Frequency Hopping Minimizes Exposureto Data Loss Due to Noise

7 ~93%

5MHz noise source

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

Piconet A Contention

Total Transmission Slots: 100 Transmission Slots Hit: 0 Transmission Efficiency: ~100%Active Piconets: 1 7 ~93%

5MHz noise source

®

www.xilinx.com

Frequency Hopping WithMultiple Piconets

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

Piconet A Piconet B Piconet C Piconet D Contention Contention Contention Contention

Total Transmission Slots: 400 Transmission Slots Hit: 20 Transmission Efficiency: ~95%Active Piconets: 4

®

www.xilinx.com

Bluetooth Piconets DegradeGracefully with Density...

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

Piconet A Piconet B Piconet C Piconet D Piconet E Piconet F Piconet G Piconet H Piconet I Piconet JContention Contention Contention Contention Contention Contention Contention Contention Contention Contention

Total Transmission Slots: 1000 Transmission Slots Hit: 112 Transmission Efficiency: ~89%Active Piconets: 10

®

www.xilinx.com

...And Maintain ReasonablePerformance Even In High Densities

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

Piconet A Piconet B Piconet C Piconet D Piconet E Piconet F Piconet G Piconet H Piconet I Piconet JPiconet K Piconet L Piconet M Piconet N Piconet O Piconet P Piconet Q Piconet R Piconet S Piconet TContention Contention Contention Contention Contention Contention Contention Contention Contention Contention

Total Transmission Slots: 2000 Transmission Slots Hit: 420 Transmission Efficiency: ~79%Active Piconets: 20