Session 3 - Learning Outcomes
By the end of this session you will be able to:
 Compare and contrast the following wireless
networking technologies:
– Microwave, satellite, radio and infrared.
 Discuss
relative advantages and disadvantages of
wireless LANs over wired LANs.
 Explain how the cellular technology works.
 Describe the potential applications of wireless
LAN and Bluetooth technology.
Nurul Sarkar, AUT
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Topics
 Microwave
 Satellite
 Radio
 Infrared
 Cellular
technology
 Wireless LAN
 Bluetooth technology
Nurul Sarkar, AUT
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References
 WebLan-Designer:
http://elena.aut.ac.nz/homepages/weblandesigner
 Textbook Ch. 6 – Telecommunication Technologies
for E-Business.
 Lough, D. L. et al. “A short tutorial on Wireless
LANs and IEEE802.11”
http://www.computer.org/students/looking/sum…/ieee802.htm
l
 Blankenbeckler,
D. “An In troduction to Bluetooth”
http://www.wirelessdevnet.com/channels/blue../bluetooth.htm
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Key terms
 Microwave
 Satellite
 Radio
 Infrared
 Line-of-sight
 Geosynchronous
 transponder
 Earth
station
 Wireless LAN
Nurul Sarkar, AUT
 Cellular
networks
 CDMA2000
 GSM
 GPRS
 Bluetooth
 Mobile JetStream
 Gigahertz
 Terahertz
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Wireless and mobile computing
technologies
 Communications
–
–
–
–
–
–
can be
Terrestrial Microwave
Satellite Microwave
Infrared
Cellular
Radio
Wireless LANs and WANs.
 Devices
include
– laptop, palmtop, pocket computer, PDA (personal
digital assistant), cell-phones, and other hand-held
devices.
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Terrestrial Microwave
 An
example of directional wireless transmission.
 A parabolic dish antenna is usually directed
toward a receiving antenna in a line-of-sight
configuration.
 Characteristics
» Frequency range: 2 - 40 GHz
» Bandwidth: 7-220 MHz, Data rate: 1Mbps 10Gbps
 Applications
» Long haul telecommunications (both voice and TV)
» short point to point links (TV or data)
» data link between LANs.
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Satellite Microwave
 Geo-synchronous
earth orbit (GEO)
» 36,000km above the earth surface. 3 satellites can be
used to cover the whole world.
 Medium
earth orbit (MEO)
» within 6000 miles from Earth. More than 10 satellites to
cover the planet.
 Low
earth orbit (LEO)
» within 1000 miles from Earth. Few hundred satellites to
cover the planet. Iridium, Teledisc, Globalstar.
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Infrared technology
Requires
transceivers
Transceivers must be line-of-sight
Frequency range: 300GHz – 200THz
Data rate: 1-16Mbps
Applications:
» LANs where no cabling required
» short distance communication (within a room)
» remote control (TV/Video)
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Broadcast radio
 Generally
omnidirectional
» does not require a disk-shaped antenna
 Frequency
range
» 3kHz to 300GHz
» Data rate: 1-10Mbps
» covers AM, FM, VHF and part of UHF band
 Applications
» Radio broadcasting (AM, FM, short waves)
» data networks
» Cellular networks
 Main
source of impairment
» multipath interference caused by reflection
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Wireless communication networks
 Wide
area networks
– Uses media from a telephone company
» Cellular systems, Satellite systems, Pagers
 Local
area networks
– Network within ones property
» Wireless LANs
 Personal
area networks
– Up to 10 meter coverage
» Bluetooth technology
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Wireless wide area networks
Target Applications


Metro/Geographical area
Ubiquitous public connectivity with virtual private
networks
TDMA
CDMA
GSM
CDPD
2G/3G Technology Characteristics




Licensed Wireless Spectrum
Multi-cell coverage for metropolitan/wide area
mobility
Modest to high power output (200-1000mw)
2G: 28-56Kbps  3G: 144Kbps-2Mbps
Nurul Sarkar, AUT
3G
UMTS
CDMA 1X
GPRS
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Cellular technology



1G: Analog technology – eg. AMP (Advanced mobile phone
system)
2G: Digital narrowband technology – GSM, CDMA
3G: Digital wideband technology – CDMA2000, W-CDMA
Cell
Optical fibre
Mobile telephone switching office
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Wireless WAN technologies
 Nextel
– One transmitter covering a large area. 2-way radio dispatch
service. Used by Taxis and public safety people.
 Paging
– One directional, point-to-point, character/ numerical based (display
caller telephone number).
– Cheaper and simpler than cellular phone service
 I-Mode
– Packet based wireless phone service. Offered by NTT DoCoMo in
Japan. Audio and video over hand held devices.
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Wireless LAN Technologies
Target Applications:


Building or Campus
Enterprise / premises advanced application voice &
data network extension.
CT2
UPCS
DECT
PHS
IEEE 802.11 wireless LAN:




Unlicensed wireless spectrum
Multi-cell coverage for workplace mobility &
roaming.
Low to modest power output (30-100mw)
2-11Mbps today 22-54Mbps in 12-24 months
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802.11
802.11b
802.11a
HiperLAN2
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Overview of wireless LAN
 Supports
mobility
 Medium
– Radio frequencies (including microwave).
 Applications
– Retail shops, Hospitals, Airports, Warehouses
 Standards
– IEEE 802.11b (up to 11 Mbps)
– IEEE 802.11a/g (up to 54 Mbps)
 Configurations
– Ad hoc network (Peer-to-peer)
– Infrastructure network.
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IEEE 802.11 Configurations
Wired Backbone Network
Access point
Infrastructure Network
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Ad hoc Network
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Wireless card and Access point
IEEE 802.11a card
IEEE 802.11a AP
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Example of
wireless LAN connectivity
Wireless laptops connecting to a backbone wired LAN through a
network access point that can support 50 clients over 500 feet.
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Wireless LAN growth
 Rapid
growth since IEEE 802.11b standard agreed
by the industry in 1998.
 Gartner Dataquest Study - Sept 2002
– Shipments of WLAN equipment will grow 73 percent in
2002 to 15.5 million units
– Mobile Computer shipments with WLAN
» 2000
9%
» 2003
50%
» 2007
90%
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Overview of Bluetooth technology
 Short-range
(up to 10 m) radio technology
 Connect home and office based systems in a
network. Connect PCs, printers, telephones,
stereos, TVs.
 Modest performance (721 Kbps)
 Low power - well suited to handheld
applications.
 Support for both voice and data.
 Packet switching technology.
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M-commerce (1)
 Transactions
and non-transaction functions
over wireless networks.
 Growth due to:
–
–
–
–
Newer and smaller technologies
More mobile populations
Deregulation of telecommunication markets
Less costly infrastructure than wired alternative
 Slower
Nurul Sarkar, AUT
to grow in US than Europe and Asia
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