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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.

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Topics

Microwave Satellite Radio Infrared Cellular technology Wireless LAN Bluetooth technology

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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.html

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

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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Target Applications Metro/Geographical area Ubiquitous public connectivity with virtual private

networks

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

3G3G

UMTSUMTS

CDMA 1XCDMA 1X

GPRSGPRS

3G3G

UMTSUMTS

CDMA 1XCDMA 1X

GPRSGPRS

TDMATDMA

CDMACDMA

GSMGSM

CDPDCDPD

Wireless wide area networks

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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

Mobile telephone switching office

Optical fibre

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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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Target Applications: Building or Campus Enterprise / premises advanced application voice &

data network extension.

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

CT2CT2

UPCSUPCS

DECTDECT

PHSPHS

802.11802.11

802.11b802.11b

802.11a802.11a

HiperLAN2HiperLAN2

802.11802.11

802.11b802.11b

802.11a802.11a

HiperLAN2HiperLAN2

Wireless LAN Technologies

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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

Ad hoc Network

Wired Backbone Network

Access point

Infrastructure Network

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Wireless card and Access point

IEEE 802.11a cardIEEE 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 to grow in US than Europe and Asia