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A Comparison of Bluetooth
and competing technologies
Technologies
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Bluetooth
IrDA
HomeRF
What we’ll talk about
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Purpose and Specifications
Communication Protocols and Network
Topology
Disadvantages and Advantages in
certain scenarios
Application comparison, consumer
criteras, business analysts
Purpose
 Why Bluetooth?
 The Bluetooth specification is a global technology that allows
wireless communication and networking between PCs and other
portable devices.
 Why HomeRF?
 HomeRF enables different consumer electronic devices to
communicate with each other while providing users with a
complete home network solution. Users will be able to dial in
from a remote location and control any device.
 Why IrDA?
 IrDA is intended for point-to-point links between two devices
for simple data transfers and file synchronization.
Technical Specifications
 Transmission Technology
 Bluetooth & HomeRF: Radio Frequency
 IrDA: Infrared Light Beams
 Spectrum
 Bluetooth & HomeRF: 2.45 GHz
 IrDA: Optical
Technical Specification (cont.)
 Connection Type
 Bluetooth & HomeRF: spread spectrum
 IrDA: Infrared, narrow beam
 Data Rate
 Bluetooth: 1 MB
 HomeRF: 2 MB
 IrDA: 4MB
Technical Specification (cont.)
 Range
Bluetooth: 3 meters
HomeRF: 50 meters
IrDA: 1 meter
 Maximum # of devices
Bluetooth: Up to 8 devices per piconet
HomeRF: Up to 127 devices per network
IrDA: 2 devices
 Optimal Use
Bluetooth:
HomeRF: Home Networking
IrDA: Short Range: one-to-one data exchange
Communication Protocols
Provides what application are able to run.
Applications
RFCOMM / SDP
L2CAP
Host Controller Interface (HCI)
Link Manager (LM)
Baseband
Radio
Bluetooth
RFCOMM: Provides emulation of serial ports over the
L2CAP.
SDP: Provides a means for applications to discover
which services are available and to determine the
characteristics of those available services
Provides connection-oriented and connectionless data
services to upper layer protocols with protocol
multiplexing capability, segmentation, and reassembly
operation and group abstractions.
Provides a command interface to the baseband
controller and link manager, and access to hardware
status and control registers.
Carries out link setup, authentication, link
configuration, etc.
Manages physical channels and links (asynchronous
and synchronous), handles packets, paging and
inquiry to access Bluetooth devices in the area.
Defines the requirements for the Bluetooth transceiver
device.
Communication Protocols (cont.)
HomeRF uses, references and maps existing network
layers.
Existing Upper Layers
• MAC layer is optimized for the home environment and is
designed to carry both voice and data traffic.
•Good support for voice and data by using both TDMA and
CSMA/CA access mechanisms.
TCP
UDP
•Support for 4 high quality voice connections.
DECT
IP
•High data throughput 1.6Mbps.
•Data security.
•Power management for Isochronous and Asynchronous
nodes.
•24 bit Network ID.
HomeRF MAC Layer
HomeRF PHY Layer
HomeRF
• Physical layer has been modified significantly to reduce
cost, while still maintaining more than adequate
performance for home usage scenarios .
•Transmit power up to +24dBm
• Receiver Sensitivity in 2FSK
• Optional low power transmit mode: 0 to 4 dBm for
portable devices.
Communication Protocol (cont).
Infrared Link
Management
Protocol (IrLMP)
Infrared Link
Access Protocol
(IrLAP)
Physical Signaling
Layer
• Provides multiplexing of the IrLAP
layer.
• Multiple channels above an IrLAP
connection
•Provides protocol and service
discovery by 121.
• Provides a device-to-device
connection
• Device discover procedures
•Handles hidden nodes
• Provides continuous operation
from contact.
• wireless point-to-point link
between 2 independent nodes
•Data packets are protected using a
CRC.
• Data transmission from 9600 b/s
Network Topology
Bluetooth Piconet and Scatternet
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Piconet connects 7 devices with one
host talking to 7 clients.
Clients have to talk to each other
through the host.
Scatternet allows groups of piconets to
communicate with each other.
Scatternet also has a host controlling
groups of piconets.
Spectrum Collisions
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HomeRF, Bluetooth, IEEE 802.11b use the same
ISM 2.45 GHz frequency band.
If all 3 used in same vicinity, the technologies will
disrupt and/or cancel each other.
With FHSS and different hop rates (Bluetooth1600 hops/sec, HomeRF?) it minimizes the
changes that they will interfere with each other.
HomeRF Interference Immunity
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Frequency Hopping Spread Spectrum
Corruption happen only in small packets
High power transmission
Able to avoid some of the interfering
frequency
Hopset adaptation makes sure that
retry will be free of interference
Less consecutive “bad hops”
HomeRF Security
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128-bit key encryption, 32-bit Initialization
Vector(repeats every half a year)
Network ID needed to synchronize
frequency hopping
Denial service attack unlikely
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Disruptor must determine the frequency of HomeRF access
point
Access points hop on independent sequences and time
bases
HomeRF MAC ignores commands from foreign network
IDs.
Advantage and Disadvantage of the three
technologies: Bluetooth
Advantage of Bluetooth
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Ad hoc connection
Better range than IR
Low power consumption
Connect through walls
Omnidirectional
Implemented by a large
number of companies
Voice and data
transmission
Disadvantage of Bluetooth
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Low bandwidth
Interference
Collides with HomeRF
No Window XP support
New technology, buggy,
not much tools
Current cost is high,
$20
Radiation
Advantage and Disadvantage of the three
technologies: HomeRF
Advantage of HomeRF
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Security
Digital voice
transmission
Peer to peer and
host/client connection
simultaneously
Interference immunity
Dedicated
Internet/multimedia
support
Disadvantage of HomeRF
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Collides with Bluetooth
and IEEE 802.11b
Competitor’s price
coming down
Multimedia and
telephony application
not on market
Radiation
Advantage and Disadvantage of the three
technologies: IrDA
Advantage of IrDA
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Cheap $2
Compact, lightweight,
low-power
Intuitive and easy to
use
Noninterfering
Best ad hoc, point and
shoot
Inherently more secure
than RF
Disadvantage of IrDA
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Line of sight only
Device cannot move
around while
transmitting
Point to point
connection only
Short distance
Application usage: Bluetooth
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Cell phone and PDA: Bluetooth
Needs filled by Bluetooth
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Connect to multiple devices at the same time
Unconsciousness synchronization
Small, low energy consumption
Current implementation
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Make Stylus into cell phone and keep PDA as base
Able to walk around the room while on the
phone(stylus)
Application usage: Bluetooth
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Cell phone and PDA: Bluetooth Cont.
Application can be platform and hardware
independent
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Bluetooth HCI (Host Control Interface) layer
allows abstraction from hardware ie PCI card or
USB adaptor
Java/JINI allows abstraction from OS
Bluetooth perfect for use in multiple devices
connection on low bandwidth
Application usage: IrDA
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E-Business cards: IrDA
Needs filled by IrDA
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More secure than RF
Cheap
Easy to use
Interference free
Current implementation
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Pint point who you want to share the business
card with
Able to exchange information fast and very ad
hoc, point and click
Application usage: IrDA
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IrDA perfect for use in close proximity simple
connection.
Calender, Address Book, Messages
synchronizations
Application usage: HomeRF
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Video conference: HomeRF
Needs filled by HomeRF
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Support multiple digital voice lines
Transport voice and data simultaneously
Secure, encrypted messages
Higher interference resistance than Bluetooth
Multimedia and Internet support
Current implementation
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Perform video conference across the Internet with
dedicated support for both voice and data
Encrypt meeting with HomeRF security
Application usage: HomeRF
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HomeRF perfect for use with
multimedia devices.
Summary
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Bluetooth
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HomeRF
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RF
Portable one-to-many network
Cell phone and PDA
RF
Home and multimedia devices
Video conference
IrDA
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Infrared
Portable one-to-one network
Calendar, address book, E business cards