Untie Yourself

1
- Untie Yourself -

• Anwar M. Haneef
• Multimedia Networks Laboratory
• Electrical and Computer Engineering, UMASS

2
Agenda

• Whos Got Dental Floss ?
• Introduction
• Usage Model
• Birds Eye View
• The Bluetooth Architecture
• Research Directions
• Bluetooth Products
• References

3
Agenda

• Whos Got Dental Floss ?
• Introduction
• Usage Model
• Birds Eye View
• The Bluetooth Architecture
• Research Directions
• Bluetooth Products
• References

4
Whos Got Dental Floss ?

• Bluetooth derived from Herald Blatand
• Nickname derived from his dark complexion - and
  not from his teeth
• Viking king (940-985 A.D.) who united Denmark and
  Norway
• Ericsson named this technology in his honor the
  uniting force

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Agenda

• Whos Got Dental Floss ?
• Introduction
• Usage Model
• Birds Eye View
• The Bluetooth Architecture
• Research Directions
• Bluetooth Products
• References

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Introduction

• A cable replacement technology
• 1 Mb/s symbol rate
• Range 10 meters
• Single chip radio baseband
• at low power low price point

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Introduction

• Open Specification
• 2164 Member SIG makes it publicly available and
  royalty free
• Short-range Wireless
• A solution to the confusion of connecting the
  myriad of devices
• Voice and Data
• Integration of voice with data unifying both
  worlds for the future
• Anywhere in the World
• Operate within a chosen ISM band accessible
  universally

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Agenda

• Whos Got Dental Floss ?
• Introduction
• Usage Model
• Birds Eye View
• The Bluetooth Architecture
• Research Directions
• Bluetooth Products
• References

9
Usage Model

• Cordless Computer
• Ultimate Handset
• Three-in-one phone
• Interactive Conference
• Internet Bridge
• Speaking Laptop
• Automatic Synchronizer
• Instant Postcard
• Hidden Computing

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Cordless Computer
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Ultimate Headset
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Interactive Conference
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Internet Bridge
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Internet Bridge
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Agenda

• Whos Got Dental Floss ?
• Introduction
• Usage Model
• Birds Eye View
• The Bluetooth Architecture
• Research Directions
• Bluetooth Products
• References

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Birds Eye View

• A hardware/software/protocol description
• An application framework

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Agenda

• Whos Got Dental Floss ?
• Introduction
• Usage Model
• Birds Eye View
• The Bluetooth Architecture
• Research Directions
• Bluetooth Products
• References

18
Bluetooth Specification
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Bluetooth Protocol Stack
Application Group
Middleware Protocol Group
Transport Protocol Group
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Transport Protocol Group
Composed of protocols to allow Bluetooth devices
to locate each other and to create, configure and
manage both physical and logical links that allow
higher layer protocols and applications to pass
data through these transport protocols
Applications
SDP
RFCOMM
Audio
L2CAP
Link Manager
Baseband
Transport Protocol Group
RF
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Middleware Protocol Group
Additional transport protocols to allow existing
and new applications to operate over Bluetooth.
Packet based telephony control signaling protocol
also present. Also includes Service Discovery
Protocol.
Applications
SDP
RFCOMM
Middleware Protocol Group
Audio
L2CAP
Link Manager
Baseband
RF
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Application Group
Applications
Application Group
SDP
RFCOMM
Consists of Bluetooth aware as well as un-aware
applications.
Audio
L2CAP
Link Manager
Baseband
RF
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Bluetooth Specification
Applications
SDP
RFCOMM
Ericsson Bluetooth Module
Audio
L2CAP
Link Manager
Baseband
RF
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Bluetooth Protocol Stack
Application Group
Middleware Protocol Group
Transport Protocol Group
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Transport Protocol Group
Applications
SDP
RFCOMM
Audio
L2CAP
Link Manager
Baseband
Transport Protocol Group
RF
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Bluetooth Radio Specifications
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Design Considerations
Noise, interference
power
spectrum
Recovered data signal
cost
Goal

• high bandwidth
• conserve battery power
• cost lt 10

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Unlicensed Radio Spectrum
?
12cm
5cm
33cm
26 Mhz
83.5 Mhz
125 Mhz
902 Mhz
2.4 Ghz
5.725 Ghz
2.4835 Ghz
5.785 Ghz
928 Mhz
802.11 Bluetooth Microwave oven
unused
cordless phones baby monitors Wireless LANs
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Bluetooth Radio Link
1Mhz
. . .
79
1
2
3
83.5 Mhz

• Frequency hopping spread spectrum
• 2.402 GHz k MHz, k0, , 78
• 1,600 hops per second
• GFSK modulation
• 1 Mb/s symbol rate

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Bluetooth Radio Design

• Low Cost
• Single chip radio (minimize external components)
• Todays technology
• Time division duplex
• Low Power
• Standby modes Sniff, Hold, Park
• Low voltage RF
• Robust operation
• Fast frequency hopping 1600 hops/sec
• Strong interference protection
• Fast ARQ
• Robust access code
• Forward header correction

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Baseband
Applications
SDP
RFCOMM
Audio
L2CAP
Link Manager
Baseband
RF
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Bluetooth Physical Link

• Point to point link
• master - slave relationship
• radios can function as masters or slaves

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Operation States
Inquiry
Page
Connected
Standby
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Operation States

• Before any connections in a piconet are created,
  all devices are in STANDBY mode.
• An unconnected unit periodically "listens" for
  messages every 1.28 seconds.
• Each time a device wakes up, it listens on a set
  of 32 hop frequencies defined for that unit.
• The number of hop frequencies varies in different
  geographic regions 32 is the number for most
  countries.

Standby
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Operation States
Inquiry
Page
The connection procedure for a non-existent
piconet is initiated by any of the devices, which
then becomes master of the piconet thus created.
A connection is made by a PAGE message being sent
if the address is already known, or by an INQUIRY
message followed by a subsequent PAGE message if
the address is unknown.
Standby
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Operation States
Inquiry

• The INQUIRY message is typically used for
  finding Bluetooth devices, including public
  printers, fax machines and similar devices with
  an unknown address. The INQUIRY message is very
  similar to the page message, but may require one
  additional train period to collect all the
  responses.
• A power saving mode can be used for connected
  units in a piconet if no data needs to be
  transmitted. The master unit can put slave units
  into HOLD mode, where only an internal timer is
  running. Slave units can also demand to be put
  into HOLD mode. Data transfer restarts instantly
  when units transition out of HOLD mode. The HOLD
  is used when connecting several piconets or
  managing a low power device such as a temperature
  sensor.

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Connection Setup

• Inquiry - scan protocol
• to lean about the clock offset and device address
  of other nodes in proximity

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Inquiry on the time axis
f1
f2
Slave1
Master
Slave2
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Operation States
Page

• In the initial PAGE state, the master unit will
  send a train of 16 identical page messages on 16
  different hop frequencies defined for the device
  to be paged (slave unit). If no response, the
  master transmits a train on the remaining 16 hop
  frequencies in the wake-up sequence.
• The maximum delay before the master reaches the
  slave is twice the wakeup period (2.56 seconds)
  while the average delay is half the wakeup period
  (0.64 seconds).

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Piconet Formation

• Page - scan protocol
• to establish links with nodes in proximity

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Bluetooth Addressing

• Bluetooth device address (BD_ADDR)
• 48 bit IEEE MAC address

• Active Member address (AM_ADDR)
• 3 bits active slave address
• all zero broadcast address

• Parked Member address (PM_ADDR)
• 8 bit parked slave address

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Physical Link Types

• Synchronous Connection Oriented (SCO) Link
• slot reservation at fixed intervals

• Asynchronous Connection-less (ACL) Link
• Polling access method

m
s1
s2
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Inter-Piconet Communication
Cordless headset
Cell phone
Cell phone
Cordless headset
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Baseband Summary

• TDD, frequency hopping physical layer
• Device inquiry and paging
• Two types of links SCO and ACL links
• Multiple packet types (multiple data rates with
  and without FEC)

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Link Manager Protocol

• Setup and management
• of Baseband connections
• Piconet Management
• Link Configuration
• Security

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Piconet Management

• Attach and detach slaves
• Master-slave switch
• Establishing SCO links
• Handling of low power modes ( Sniff, Hold, Park)

Paging
req
Master
Slave
response
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Low Power (Sniff) Mode
Sniff offset
Sniff duration
Sniff period

• Traffic reduced to periodic sniff slots

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Low Power (Park) Mode
Beacon instant
Master
Beacon interval

• Power saving keep more than 7 slaves in a
  piconet
• Give up active member address, yet maintain
  synchronization
• Communication via broadcast LMP messages

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Link Configuration

• Quality of service
• Polling interval
• Broadcast repetition
• Power control
• Packet type negotiation
• Multi-slot packets

Paging
LMP_quality_of_service
Master
Slave
LMP_not_Accepted
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Authentication

• Authentication is based on link key (128 bit
  shared secret between two devices)
• How can link keys be distributed securely ?

challenge
response
Claimant
Verifier
accepted
Link key
Link key
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Pairing (Key Distribution)

• Pairing is a process of establishing a trusted
  secret channel between two devices (construction
  of initialization key Kinit)
• Kinit is then used to distribute unit keys or
  combination keys

PIN Claimant address
PIN Claimant address

Claimant
Verifier
Random number
challenge
Random number
Random number
response
accepted
Kinit
Kinit
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Encryption

• Encryption Key ( 8 128 bits)
• Derived from the Link key

Encryption mode
Key size
Start encryption
Encrypted traffic
Stop encryption
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Link Layer Protocol Summary

• Piconet management
• Link configuration
• Low power modes
• QoS
• Packet type selection
• Security authentication and encryption

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L2CAP
Logical Link Control and Adaptation Protocol
Applications
SDP
RFCOMM
Data

• L2CAP provides
• Protocol multiplexing
• Segmentation and Re-assembly
• Quality of service negotiation

Audio
L2CAP
Link Manager
Baseband
RF
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Multiprotocol Encapsulation
IP
IP
RFCOMM
reliable, in-order, flow controlled, ACL
link with possible duplication

• Desired features
• Protocol multiplexing
• Segmentation and re-assembly
• Quality of service

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Multiplexing and Demultiplexing
IP
RFCOMM
IP
RFCOMM
Circuit or connection-less ?
Why is L2CAP connection oriented ?

• Baseband is polling based
• Bandwidth efficiency
• - carry state in each packet Vs. maintain it at
  end-points
• Need ability for logical link configuration
• MTU
• reliability (Flush timeout option)
• QoS (token bucket parameter negotiation)

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L2CAP Summary
Design constraints

• Simplicity
• Low overhead
• Limited computation and memory
• Power efficient

Assumptions about the lower layer

• Reliable, in-order delivery of fragments
• Integrity checks on each fragment
• Asynchronous, best effort point-to-point link
• No duplication
• Full duplex

Service provided to the higher layer

• Protocol multiplexing and demultiplexing
• Larger MTU than baseband
• Point to point communication

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Bluetooth Protocol Stack
Application Group
Middleware Protocol Group
Transport Protocol Group
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Middleware Protocol Group
Applications
SDP
RFCOMM
Middleware Protocol Group
Audio
L2CAP
Link Manager
Baseband
RF
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Bluetooth Service Discovery Protocol
Applications
SDP
RFCOMM
Data
Audio
L2CAP
Link Manager
Baseband
RF
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Example use of SDP

• Establish L2CAP connection to remote device
• Query for services
• search for specific class of service, or
• browse for services
• Retrieve attributes that detail how to connect to
  the service
• Establish a separate (non-SDP) connection to user
  the service

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Serial Port Emulation using RFCOMM
Applications
SDP
RFCOMM
Data

• Serial Port emulation on top of a packet oriented
  link
• Similar to HDLC
• For supporting legacy apps

Audio
L2CAP
Link Manager
Baseband
RF
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Serial Line Emulation over Packet based MAC
RFCOMM
RFCOMM
L2CAP
L2CAP

• Design considerations
• framing assemble bit stream into bytes and,
  subsequently, into packets
• transport in-sequence, reliable delivery of
  serial stream
• control signals RTS, CTS, DTR

• Options
• collect MTU bytes and then send
• wait until a timeout
• send whatever is available

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IP over Bluetooth
Applications
SDP
RFCOMM
GOALS
Data

• Internet access using cell phones
• Connect PDA devices laptop computers to the
  Internet via LAN access points

Audio
L2CAP
Link Manager
Baseband
RF
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LAN Access Point Profile
IP
Access Point
PPP
RFCOMM
L2CAP
LMP
Baseband
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L2TP Style Tunneling
Palmtop
Access Point
PPP server
IP
IP
PPP
PPP
RFCOMM
RFCOMM
Bluetooth
Bluetooth

• Tunneling PPP traffic from access points to the
  PPP server
• 1) centralized management of user name/password
• 2) reduction of processing and state maintenance
  at each access point
• 3) seamless roaming

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Seamless Roaming with PPP
Server
AP1
AP2
MAC level registration
palmtop
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IP over Bluetooth
Next steps
Internet connectivity for non-PC devices
IP based network connectivity
peer-to-peer connectivity
IP over wireless media
Decentralized techniques for link formulation,
naming, addressing, and routing
Investigation of the right design point
for running IP over toasters, light switches,
fire alarms
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Agenda

• Whos Got Dental Floss ?
• Introduction
• Usage Model
• Birds Eye View
• The Bluetooth Architecture
• Research Directions
• Bluetooth Products
• References

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Research Directions
Internet
Plug-n-play applications
Resource Discovery
Routing over scatternets
Techniques for link formation
Will the current solutions for each layer work in
this environment?

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Agenda

• Whos Got Dental Floss ?
• Introduction
• Usage Model
• Birds Eye View
• The Bluetooth Architecture
• Research Directions
• Bluetooth Products
• References

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Bluetooth Products

• Motorola USB adapter
• WIDCOMM Inc. BlueConnect for Handspring Visor
• PRIMAX Blueport Wireless Modem
• PRIMAX Blueport LAN Access Point
• Primax Blueport PCMCIA Card
• Zucotto Wirelesss Java based Bluetooth upper
  protocol stack
• Ericsson Bluetooth headset
• Ericsson R520 Bluetooth Phone
• Around 139 qualified products

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Agenda

• Whos Got Dental Floss ?
• Introduction
• Usage Model
• Birds Eye View
• The Bluetooth Architecture
• Research Directions
• Bluetooth Products
• References

74
References

• Bluetooth Revealed, Miller, B., Bisdikian, C.,
  Prentice Hall PTR, 2001
• Personal Area Networking over Bluetooth, Pravin
  Bhagwat, ACM MOBICOM 2000, Half Day Tutorial
• BluetoothThe universal radio interface for ad
  hoc, wireless connectivity, Jaap Haartsen.
  Ericsson review 03, 1998. (http//www.ericsson.com
  /review/issues.taf )
• Bluetooth version 1.0 specifications
• http//www.bluetooth.com/developer/specificat
  ion/core.asp
• Part A, Radio Specification
• Part B, Baseband
• Part C, Link Manager Protocol
• Part D, Logical Link Control and Adaption
  Protocol Specification
• Part E, Service Discovery Protocol (SDP)
• Bluetooth version 1.0 profiles
• http//www.bluetooth.com/developer/specificat
  ion/profiles.asp
• Part K9, LAN access profile
• http//qualweb.opengroup.org/Template.cfm?LinkQual
  ifiedQualifiedProducts

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Thank You !!!

• Anwar M. Haneef
• a.m.haneef_at_ieee.org
• http//www-unix.ecs.umass.edu/ahaneef