A proprietary open wireless technology established by the: Bluetooth® Special Interest Group (SIG)

Presented by: Kedao Wang, Shaun Levin, Dave Chen

• • • • • • • •

History 3 Applications 4 Specifications 5-8 Components 9-12 States 13-15 Connection Setup 16-17 Development Kits 18-21 Conclusion 23 References 24

History & Creation

•

Created by telecoms vendor Ericsson in 1994

•

Named after Scandinavian King Bluetooth from 900's BCE

•

A wireless alternative to RS-232 data cables

• • •

Simple, secure, everywhere Robust, low power, low cost Simultaneously handle data and voice transmissions

Applications

Audio

- synchronization of separate stereo channels between devices

Mobile phone

- Android and iPhone

Controls

- Game Consoles, Mouse, Printer, Remote Controllers

Replacing RS-232

- GPS receivers in medical equipment, barcode scanners, and traffic control devices

Profiles: Overview

Provide standards which manufacturers follow to allow devices to use Bluetooth in the intended manner

Profiles describe

:

•

Dependencies on other profiles

• •

Suggested user interface formats Specific parts of the Bluetooth protocol stack used by the profile

Profiles: Common Uses

Audio/Video Remote Control Profile (AVRCP)

Provide standard interface for a single device to control several pieces of A/V equipment (TV, VCR, DVD, etc)

Human Interface Device Profile (HID)

Send mice, keyboards, joysticks, and game controllers presses. Low latency link with low power. Used for Playstation 3 and Wii controllers.

Advanced Audio Distribution Profile (A2DP)

High quality audio streamed from one device to another

Basic Imaging Profile (BIP)

Designed for sending images between devices and includes the ability to resize and convert images

Serial Port Profile (SPP)

Emulates a serial cable to provide a simple substitute for existing RS-232, including the familiar control signals

GATT Profile

General development profile installed on Texas Instrument Development Kits

Versions

Version

1 (Basic Rate) 2 (Enhanced Data Rate) 3 (High Speed) 4 (Low Energy)

Improvements

GFSK modulation

, 1 Mb/s

π/4-QPSK modulation

: 2 Mb/s

8DPSK modulation

: 3 Mb/s Bluetooth establishes and negotiates a 802.11 (WiFi) link at 24 Mb/s

Low energ

y mode: 200 kbit/s over Bluetooth

Power Advantages

Reduced Duty Cycle Enhanced Power Controls Ultra-low power idle mode

π/4-QPSK

GFSK

Range

Manufacturer can choose to create the device to match 1 of 3 class models

Class

1 2 3

Expected Range

42 meter 16 meter 10 meter

Power

100 mW 2.5 mW 1 mW

Networks: Piconets and Scatternets

Piconet

: One master => up to

7

slaves All devices share the master's clock Up to 255 further slave devices can be inactive

Scatternet

: Two or more piconets to form a scatternet One device simultaneously is master in one piconet and slave in another http://www.freeopenbook.com/upgrading-repairing-networks/ch22lev1sec3.html

Networks: Frequency Hopping

•

Versions use different modulations schemes o The modulation rate changes with Frequency-Hopping Spread Spectrum (FHSS)

• •

2.402 GHz to 2.480 GHz

, 79 frequency bands of 1 MHz each

•

To minimize interference between piconets, paired-up devices hop among 79 frequency bands together

1600 times/sec

•

Data can be transferred between the master and one slave device at a time The master chooses the slave to address, and switches the slaves through a round-robin fashion

Synchronization and Transmission

• •

Piconet

is synchronized by master's clock o Slaves adapt internal clock with a timing offset to match master

Clocks

o Basic

clock

rate is 3.2 KHz o o 2 clock ticks make up a

slot

1, 3, or 5 slots make up a

packet

•

•

Time-division duplex (TDD)

scheme = alternately transmit and receive data To transmit data, need: o Channel Hopping Sequence = derived from BD_ADDR of master o o Phase of Hopping Sequence = derived from clock of master Channel Access Code (CAC) = derived from BD_ADDR of master

Packets

Access Code:

• • • • • 72 bits timing sync offset compensation paging inquiry

Header:

• • 54 bits packet acknowledgement • • • • packet numbering flow control slave address error check for header

Payload:

• • 0-2745 bits either voice field, data field, or both • if it has a data field, payload also contains payload header There are 13 special packets for synchronizing and making connections

Four Types of Device Addressing

BD_ADDR

(Bluetooth Device Address) 48-bit device address used to identify each transceiver

AM_ADDR

(Active Member Address) 3-bit MAC address of the active slave device

PM_ADDR

(Parked Member Address) 8-bit MAC address of the parked slave device

AR_ADDR

(Access Request Address) Used by parked slaves Determines when it can ask the master for messages

Connection States

Devices have two major states

Standby (disconnected)

• • • •

Default state Low power Only native clock is running No interaction with any device

Connection

•

Master and slaves can exchange packets

• •

Uses master's clock Uses master access code

Connection Modes

Active Mode

Actively participates on the channel Master schedules the transmissions Slaves only respond if addressed Has AM_ADDR (unless it is the master)

Sniff Mode

(low power-saving) (slave only) Slave listens to piconet at programmable reduced rate If addressed, switch to active mode Has AM_ADDR

Hold Mode

(medium power-saving) (slave only) Slave waits until an internal timer runs out Master and/or slave can put the slave on HOLD Data transfer restarts instantly once HOLD finishes Has AM_ADDR

Park Mode

(high power-saving) (slave only) Device is still synchronized to piconet, but does not participate Has given up MAC (AM_ADDR) Occasionally listens to master to re-synchronize and check on messages Has PM_ADDR instead of AM_ADDR

Connection Setup: Step 1 (Discover)

• •

Source

sends out inquiry packet and waits for an inquiry reply If a

destination

receives an inquiry packet, it: o Enters the inquiry response state o Sends the inquiry reply to the source

Connection Setup: Step 2 (Connect)

1. The source sends special ID packet (page) to the destination 2. The destination receives the page 3. The destination sends a reply to the source 4. The source sends an FHS (Frequency Hopping Synchronization) packet to the destination a. FHS contains BD_ADDR and clock of the source in 144-bit data and 16-bit CRC 5. The destination sends its second reply to the source 6. The destination and source switch to modes where they can interact http://www.palowireless.com/infotooth/tutorial.asp

Development Kits

GS-BT2416C1DB from ST Microelectronics

USB and RS 232 Serial Interface $35 - cheapest Older Bluetooth version (1.2)

Development Kits

DEV-PC-1309C-ND from CSR

$93.75

Flexible Communication Protocol Serial and Ethernet CSR also develops software for platforms with built in bluetooth (Android, iPhone) and has multiple development tools for multiple profiles

Development Kits

CC2540 Mini Development Kit from Texas Instruments

$99 Simple, flexible GATT Profile Best documentation

Development Kits

CC2540 Development Kit From Texas Instruments

$300 Complete hardware evaluation kit Complete hardware performance test platform GATT Profile

Conclusions

• • • • • • Bluetooth is a wireless communication protocol with speeds between 1 Mbps and 24 Mbps < 40m range It avoids interfering with other devices by using FHSS Its version designs have been driven by power Its connection states are defined by power consumption 'Profiles' are provided for developing application specific uses

References

http://www.m2mgsm.com/download/BT/docs/general/Bluetooth_Overview.p

d f http://www.bluetooth.com/ http://grouper.ieee.org

http://www.palowireless.com/infotooth/tutorial.asp

Questions?