Bluetooth: Technology for ShortRange Wireless Apps

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BluetoothTechnology for Short-Range Wireless
Apps
IEEE INTERNET COMPUTING MAY.JUNE 2001

• AuthorPravin Bhagwat
• Presented by Chin-Yi Tsai

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Outline

• Introduction to Bluetooth
• Bluetooth Specifications
• The Frequency Hopping technique
• Inquiry and Paging
• Piconets and Scatternets
• Bluetooth Applications
• Conclusions

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Introduction to Bluetooth

• Why Bluetooth?
• Bluetooth History
• Bluetooth Feature and motivation

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Why Bluetooth?

• 10th Century Denmark King
• King Harald united Denmark and Norway. Bluetooth
  of today will unite the world of computers and
  telecom

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Bluetooth History

• The Bluetooth Special Interest Group(SIG)
• Initially the group comprised five
  companies-IBM,Intel,Ericsson,Nokia,Toshiba
• The end of 1999 this number had increased to nine
  through the addition of 3Com, Motorola,
  Microsoft, Lucent
• By December 2000 the Bluetooth SIG had over 2000
  members

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Bluetooth feature and motivation

• Bluetooth feature
• ISM 2.4 GHz
• Small
• Simple
• Low cost
• Low power
• Short range
• Voice and data
• Point-to-point and point-to-multipoint

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Bluetooth feature and motivation

• Bluetooth motivation
• Started as cable replement technology
• Connecting with different devices
• Mobile acces to LANs/Internet
• Personal Area Network(PAN)
• Automatic synchronization of data

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Bluetooth Specifications

• Core specification
• The core specification defines all layers of the
  Bluetooth protocol stack
• Profile specification
• Special protocol
• different device,OS, and application
• interoperability

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Bluetooth Specifications
Applications
OBEX
SDP
TCS
WAP
RFCOMM
AT Commands
L2CAP
Host Controller Interface
Link Manager
Baseband/Link Controller
Radio
The Bluetooth protocol stack
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Radio

• Frequncy
• 2.40002.4835 GHz(license-free)
• Powerthere are three power class
• 1mW,2.5mW,100mW
• Modulation
• GFSK

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Baseband

• Physical channel
• Formed after connection
• Transmition type
• SCO(cricuit switch)point-to-point,voice
• ACL(packet switch),point-to-multipoint, data
• Error correction
• 1/3 FEC,2/3 FEC ,ARQ
• Timer synchronization

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Baseband

• Link controller state
• Standby
• Intermediateinquiry,inquiry scan,inquiry
  response,page,page scan,page response,master
  response
• Connectionactive,sniff,hold,park

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LMP

• Piconet management
• Attach and detach slave
• SCO and ACL connection,management
• Switch role of master,slave
• Handling low power
• Link configuration
• QoS
• Security function
• Authication,encryption,link key

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Host Controller Interface

• Host control Bluetooth module

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L2CAP

• Protocol multiplexing
• Segment and reassembly
• Negotiation
• MTU(maximum transmission unit)
• Flush timeout
• QoS

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Others

• RFCOMM
• TCS
• WAP
• OBEX
• PPP

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Profile Specifications

• Generic access
• Service discovery
• Cordless telephone
• Intercom(Walkie-Talkie)
• Serial port
• Headset

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Profile Specifications

• Dial-up networking
• Fax
• LAN access
• Generic object exchange
• Object push
• File transfer
• Synchronization

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The Frequency Hopping technique
1MHz

1
79

• Divide Frequency band into 1 MHz hop channels
• Radio hops from one channel to another in a
  pseudo
• -random manner as dictated by a hop sequence
• Hopping sequence is different for each
  piconet(masters device address and clock)
• Hop rate1600 time/second

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The Frequency Hopping technique
f(2k)
f(2k2)
f(2k4)
f(2k1)
f(2k3)
f(2k5)
Master
Slave1
Slave2
Slave3
1 slot
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Inquiry and Paging

• The purpose of inquiry and paging
• Connection establishment

Connected
Paging
Inquiry
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Inquiry and Paging
Master
Slave
Start inquiry
Inquiry scan
FHS Packet
Inquiry result
Inquiry complete
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Inquiry and Paging
Master
Slave
Page
Page Scan
Slave Page Response
Master Page Response
Uses FHS to get CAC and clk info
Assigns active addr
Connected
Connected
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Piconets and Scatternets

• Bluetooth unit can communicate with other units,
  by forming a piconet
• One unit of a piconet is defined as the master
  (the unit that establishes the piconet), the
  others units are called slaves
• One piconet consists of 1 master and up to 7
  slaves

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Piconets and Scatternets

• A group of piconets in which connections consists
  between different piconets is called a scatternet
• A unit cannot be the master in different piconet,
  since the master determines the property of a
  piconet

A scatternet example
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Bluetooth Applications

• Three-in-one Phone
• Ultimate Headset
• Automatic Synchronizer
• Internet Bridge
• Interactive Conderence
• Indoor positioning

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Conclusions

• Bluetooth eliminates the need for numerous and
  inconvenient cable attachments for devices
• Bluetooth enables the design of low-power,
  small-sized, low-cost radios that can be embedded
  in existing (portable) devices
• The Bluetooth technology will be built into
  hundreds of millions of electronic devices in
  2005
• Commpared with 802.11 and HomeRF

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Transmition type
SCO
SCO
SCO
ACL
ACL
Master
Slave1
Slave2
Slave3