1

Bluetooth Technology

By,Ms.Vicky HSU Rajan AvudaiappanComputer Networks-I [A1604]SVU CS-426

2

Introduction Originally developed by:

Ericsson Mobile Communication (Sweden) Initiated the study (1994) Low power, low cost radio interference between mobile phones and

its accessories Eliminate cables between the devices

Later IBM, INTEL, Nokia & Toshiba formed the “Bluetooth Special Internet Group (SIG)” [1998]

Developed Bluetooth 1.0 Specification (1999) Promoter group: Microsoft, Motorola, 3Com and Lucent

3

Bluetooth History Harald Bluetooth Gormson

Name of a king (Denmark, 10th century) To honor him for his contributions for

communication technology

4

Bluetooth!! Bluetooth networking standard is:

a set of rules for radio frequencies & communication (Voice and Data application)

[i.e.] Bluetooth:

A physical standard for radio signals Part of radio spectrum with ISM devices

(Industrial, Scientific and Medical Devices) Operates in 2.45 GHz range of RF spectrum

A protocol standard communications

5

Bluetooth communication Uses different radio waves to communicate

Perfect for short range communication

Uses FHSS (Frequency Hopping Spread- Spectrum) Doesn’t interfere with other Support 8 connection [ < 10 meter ] Switches b/w 79 frequencies (random) or Channel

6

Bluetooth communication Bluetooth Device

Changes frequencies - 1600 times / Sec (Disturbance could be avoided)

Piconet It is a type of network connection

(Generated by the Bluetooth devices)

Bluetooth – Other Bluetooth devices able to connect automatically

(in discoverable mode)

7

Bluetooth classification Based on the power levels Based on maximum transmission capacity

Classification Power level Capacity

Class I 20 dBm 100 m

Class II 0-4 dBm 10 m

Class III 0 dBm 1 m

8

Bluetooth operation Bluetooth: Radio

Bluetooth RF (Physical layer) Operates in the unlicensed ISM band (2.4 GHz) It makes use of a frequency hop transceiver

To prevent interference and fading To make available of many FHSS carriers It makes use of a binary FM

(to reduce transceiver complexity) Data rate - up to 1 Mbps

‘Radio channel’ is shared by devices (group) They are synchronized to a common clock & Frequency hopping pattern

9

Bluetooth operation Bluetooth: Radio

‘ Bluetooth Piconet ’ A type of network connection

(Group of devices will occupying shared physical channel) Master (Synchronization reference)

clock & device address - decide channel characteristics Slave devices (Devices - that connected with the master)

‘ Frequency Hopping ’ Devices use a explicit Frequency hopping pattern

Algorithm ( Bluetooth specification address & master’s clock) Pseudo - Random sequence hopping pattern (ISM 79 freq.)

‘ Full Duplex ’ Uses Time - Division Duplex method Data transmission in the form of packets

10

Bluetooth operation Bluetooth: Link & Protocols

‘ Control Layers ’ Placed above the physical channel

Layer of links and Channels Control Protocols

‘ Physical Links ’ Connection established between

Two Piconet Bluetooth devices Master & Slave - possible Slave & Slave - impossible

Can be used to transport more than one logical layer Supports synchronous, asynchronous traffic

11

Bluetooth operation Bluetooth: Link & Protocols

Logical Links Data traffic in logical link is being multiplexed

(into the physical link by occupying slots ) Link Manager Protocol (LMP)

It is a control protocol (for baseband & physical layers) Link manager uses this LMP (to control device operations) Provide services to manage (for radio & baseband layers)

Logical Link Control and Adaptation Protocol (L2CAP) Based above the baseband layer Provides abstraction to applications and services Multiplexing & De-multiplexing of many channels

12

Bluetooth Wireless Technology

Bluetooth - for voice and data application Penetration can penetrate solid objects like walls Bluetooth chip cost : (< $3 ~ $5) – Economically

efficient Easy to use Security – Allows 3 diff. Modes

Non-secure, Service level, Link level Max bandwidth : 1 Mbps (theoretically) : 721 Kbps Low power consumption Interference very short time Good for Wireless Personal Area Network (WPAN)

13

Bluetooth Wireless Technology Quick synchronization between Bluetooth enabled devices Omni directional --> No line-of-sight requirement Ability to establish connection

(between any portable devices and a wired network) Uses globally available unlicensed ISM radio band Frequency range :

902 - 928 MHz 2.4 – 2.484 GHz

Need not require operator’s license from: Federal Communication Commission (FCC) Any other International Regulatory Board

Adopt common frequency band Can use virtually anywhere (any country in the world)

14

Bluetooth Wireless Technology System consists of:

Software, Hardware and interoperability requirements Bluetooth Baseband protocol

Combination of “Circuit & Packet switching” Easy to embedded directly into:

Existing component boards or an adapter devices Bluetooth equipment integrate easily in TCP/IP network

It uses wireless LAN & IEEE standards for data transmissions

Bluetooth frequency range used in: USA - 2402 MHz to 2480 MHz Europe - 2402 MHz to 2480 MHz Japan - 2472 to 2497 MHz

15

Bluetooth (IEEE standards) IEEE 802.15 Working group for Wireless Personal Area

Networks (WPANs)

Bluetooth technology follows “IEEE 802.15.1” standards Ver 1.0, 1.1, 1.2 & 2.0 1.2 Adaptive Frequency Hopping Reduce interference

16

Technology Characteristics Uses small data packets

Improve & Maximize interface capacity Minimize interference by:

Quick Frequency Hopping Adaptive output power

Forward Error Correction Specific method used by receivers

Detect errors in the transmission Correct errors -> Ability to correct them

Maximum availability of devices in a Piconet: 1 Master device 7 Slave devices

17

Technology Characteristics Service Support: Asynchronous, Synchronous

Asynchronous Connectionless Link (ACL) Supports for data transfer Carry either user data or control data Efficiency is best

Synchronous Connection Oriented (SCO) Link Real-time Voice support Multimedia Traffic Uses reserved bandwidth Maximum three SCO connection (64,000 bits/sec) is

possible

18

Bluetooth Links Data & Voice transmitted as packets Errors detected at receiver side

Notification to the header of the return packet Only lost or erroneous packets need to be retransmitted

ACL supports: (Data transmission) Symmetrical or Asymmetrical Packet Switched Point-to-multi point connections

Symmetrical Connection Link Max. Data rate : 433.9 Kbps (in both direction)

Asymmetrical Connection Link Max. Data rate: 723.2 Kbps (in one direction)

57.6 Kbps (in reverse direction)

19

Bluetooth Links SCO link supports: (voice transmission)

Symmetrical Circuit Switched Point-to-Point connection

Three synchronous channels of 64 Kbps They use either:

Pulse Code Modulation Std. for encoding speech (Analog ~ Digital) - PSTN

Continuously Variable Slope Delta Modulation (CVSD) Std. for encoding speech (Analog ~ Digital) More immunity to interference Best for Voice transmission than PCM over wireless

link Appropriate voice-coding scheme is being selected

(After communication between: link managers of the devices)

20

Data & Control

Voice

Application

OBEX WAP TCS SDP

RFCOMM

L2CAP

Host Controller Interface

Baseband and link controller

Link manager

Radio

Twowayvoice

Control

Bluetooth protocol stack

21

Bluetooth protocol stack TCS (Telephony Control Protocol)

Gives information about telephony services  SDP (Service Discovery Protocol)

Allows Bluetooth devices can find out what all are services supported by other Bluetooth devices

WAP (Wireless Application Protocol) & OBEX (Object Exchange)

Gives interfaces to the higher layer parts of other communication protocols

RFCOMM (Radio Frequency Communication) It is the Bluetooth serial port emulator It provides serial interface services (RS 232)

22

Bluetooth protocol stack L2CAP (Logical Link Control and Adaptation Protocol)

Multiplexes the data from higher-level layers and also alters between different packet sizes

Makes virtual connection between hosts and keeps track of multiple concurrent sessions (Ex: file transfers)

Breaks the application data into Bluetooth-size fragments for transmission, and it will do the reverse operation for the received data

Host Controller Interface Controls communication between a separate host and a Bluetooth

module Link Manager

Handles and configures links with other devices

23

Bluetooth protocol stack Broadband and Link Controller

It handles the physical links through radio as well as assembling of packets

It also controls the frequency hopping

Radio It uses for modulation and demodulation of data for transmission

and reception

24

Bluetooth Protocols

25

Bluetooth Protocols

26

Bluetooth devices…(examples)

Bluetooth Head phones

Bluetooth PDAs Bluetooth Access

points Bluetooth adapters Bluetooth projectors Bluetooth cameras Bluetooth printers Bluetooth car adapters

Bluetooth mice, keyboard

Bluetooth Handsets Bluetooth Modems Bluetooth Medical

devices Bluetooth Flash cards Bluetooth projectors Bluetooth MP3 players Bluetooth mobile PCs

27

References1. www.bluetooth.com2. Bluetooth Demystified, Nathan J.Muller, McGraw-Hill, NY, USA 20003. Bluetooth- Connect without cables, By Jennifer Bray and Charles F Sturman,

Prentice Hall PTR, Upper Saddle River, New Jersey 07458, 2001

4. Bluetooth Operation and Use, By Robert Morrow, McGraw-Hill, New York, 20025. http://www.baracoda.com/shared_docs/bluetooth_protocol.pdf6. http://www.cs.fsu.edu/~yasinsac/group/slides/carter3.pdf7. http://stephen.ksuettc.org/bluetooth.pdf8. http://www.rzo.free.fr/docs_jean/bluetooth.pdf9. www.cs.utk.edu/.../bluetooth/whatisbluetooth.gif 10. www.palowireless.com/.../spec_stack.gif11. http://www.palowireless.com/infotooth/knowbase.asp12. http://www.ericsson.com/ericsson/corpinfo/publications/review/2000_04/files/

2000046.pdf13. http://www.ieee802.org/15/ 14. http://www.cs.fsu.edu/~yasinsac/group/slides/carter3.pdf15. http://electronics.howstuffworks.com/bluetooth.htm

28

Queries ?