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THE LEADING WIRELESSTECHNOLOGY

WI-FI

A

PRESENTATION

ON

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History and Definition

Wi-Fi is a popular technology that allows an electronicdevice texchange data wirelessly (using radio waves) overa computer network, including high speed internetconnections.

The Wi-Fi Alliance defines Wi-Fi as any "wireless localarea network (WLAN) products that are based onthe Institute of Electrical and Electronics Engineers'(IEEE) 802.11 standards".

Vic Hayes has been called the "father of Wi-Fi". He wasinvolved in designing the initial standards withinthe IEEE.

Alternative wireless technologies include mobile phonestandards such as 2G,3G or 4G.

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Wireless network interface

controllerThe combination of computer and

interface controller is called a station.

All stations share a single radiofrequency communication channel.

Transmissions on this channel arereceived by all stations within range.

The hardware does not signal the userthat the transmission was delivered andis therefore called a delivery

mechanism.

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Internet access

A Wi-Fi-enabled device can connect to theInternet when within range of a networkconnected to the Internet.

The coverage of one or more(interconnected) access points-calledhotspots - can extend from an area as

small as a few rooms to as large as manysquare miles.

Wi-Fi provides service in private homes,high street chains and independent

businesses, as well as in public spaces at- - -

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Direct computer to computercommunications

Wi-Fi also allows communications directlyfrom one computer to another without anaccess point intermediary. This is called ad

hoc Wi-Fi transmission.

This wireless ad hoc network mode hasproven popular with multiplayer handheldgame consoles, such as the Nintendo

DS, Play station Portable, digital cameras,and other consumer electronics devices.

Similarly, the Wi-Fi Alliance promotes aspecification called Wi-Fi Direct for file

transfers and media sharing through a new

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Advantages

Wi-Fi allows cheaper deployment of localarea networks (LANs).

Manufacturers are building wirelessnetwork adapters into most laptops.

Wi-Fi Protected Access encryption isconsidered secure, provided a strong passphrase is used.

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Limitations

Spectrum assignments and operationallimitations are not consistent worldwide.

The current 'fastest' norm, 802.11n, usesdouble the radio spectrum/bandwidth(40 MHz) compared to 802.11a or 802.11g(20 MHz).

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Standard devices

v Wireless adapters allow devices toconnect to a wireless network.

v adapters connect to devices using variousexternal or internal interconnects such asPCI, mini PCI, USB, Express Card, Card busand PC Card.

v Wireless range-extenders or wirelessrepeaters can extend the range of an

existing wireless network.

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Embedded systems

embedded Wi-Fi modules have becomeavailable that incorporate a real-timeoperating system and provide a simplemeans of wirelessly enabling any devicewhich has and communicates via a serialport.

These Wi-Fi modules are designedby OEMs so that implementers need only

minimal Wi-Fi knowledge to provide Wi-Fi

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Multiple access points

Increasing the number of Wi-Fi access pointsprovides network redundancy, support for fastroaming and increased overall network-

capacity.

Wi-Fi implementations have moved toward"thin" access points, with more ofthe network intelligence.

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Network security

wireless network security is its simplifiedaccess to the network compared to traditionalwired networks .

business networks protect sensitive data andsystems by attempting to disallow external

access.

wireless connectivity reduces security if the

network uses inadequate or no encryption.

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Safety

The World Health Organization (WHO) says"there is no risk from low level, long-termexposure to Wi-Fi networks.

the United Kingdom's Health ProtectionAgency reports that exposure to Wi-Fi for ayear results in "same amount of radiationfrom a 20-minute mobile phone call."

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THE ENDTHE END