proiect 3.docx

7/25/2019 proiect 3.docx

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Proiect 3

Wi-Fi wireless interfaces

Student: Marcu Andrei-Marius

Grupa: 441F

Profesor: Radescu Radu


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Wi-Fi wireless interfaces

Wi-Fi(or WiFi) is a local area wireless computer networkingtechnology that allows

electronic devices to connect to the network, mainly using the 2.4 gigahertz (12 cm)UHand !

gigahertz (" cm) #H$#% radio &ands.'he ii *lliancede+ines ii as any wireless local area network (-*) product &ased on

the$nstitute o+ /lectrical and /lectronics /ngineers0($///) 2.11 standards.31However, the term

ii is used in general /nglish as a synonym +or -* since most modern -*s are &ased

on these standards. ii is a trademark o+ the ii *lliance. 'he ii 5erti+ied trademark can

only &e used &y ii products that success+ully complete ii *lliance interopera&ilitycerti+ication

testing.

%any devices can use ii, e.g. personal computers, videogame consoles, smartphones, digital

cameras, ta&let computersand digital audio players. 'hese can connect to a network resource such

as the $nternet via a wireless network access point. #uch an access point (orhotspot) has a range o+

a&out 2 meters ("" +eet) indoors and a greater range outdoors. Hotspot coverage can &e as small

as a single room with walls that &lock radio waves, or as large as many s6uare kilometres achieved

&y using multiple overlapping access points.

7epiction o+ a device sending in+ormation wirelessly to another device, &oth connected to the local network, in

order to print a document.

ii can &e less secure than wired connections, such as /thernet, precisely &ecause an intruder

does not need a physical connection. e& pages that use '-#are secure, &ut unencrypted internet
https://en.wikipedia.org/wiki/Wireless_LANhttps://en.wikipedia.org/wiki/UHFhttps://en.wikipedia.org/wiki/UHFhttps://en.wikipedia.org/wiki/UHFhttps://en.wikipedia.org/wiki/Super_high_frequencyhttps://en.wikipedia.org/wiki/ISM_bandhttps://en.wikipedia.org/wiki/Wi-Fi_Alliancehttps://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineershttps://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineershttps://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineershttps://en.wikipedia.org/wiki/IEEE_802.11https://en.wikipedia.org/wiki/Wi-Fi#cite_note-1https://en.wikipedia.org/wiki/Wi-Fi#cite_note-1https://en.wikipedia.org/wiki/Wireless_LANhttps://en.wikipedia.org/wiki/Interoperabilityhttps://en.wikipedia.org/wiki/Interoperabilityhttps://en.wikipedia.org/wiki/Smartphonehttps://en.wikipedia.org/wiki/Tablet_computerhttps://en.wikipedia.org/wiki/Wireless_access_pointhttps://en.wikipedia.org/wiki/Hotspot_(Wi-Fi)https://en.wikipedia.org/wiki/Hotspot_(Wi-Fi)https://en.wikipedia.org/wiki/Ethernethttps://en.wikipedia.org/wiki/Transport_Layer_Securityhttps://en.wikipedia.org/wiki/UHFhttps://en.wikipedia.org/wiki/Super_high_frequencyhttps://en.wikipedia.org/wiki/ISM_bandhttps://en.wikipedia.org/wiki/Wi-Fi_Alliancehttps://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineershttps://en.wikipedia.org/wiki/IEEE_802.11https://en.wikipedia.org/wiki/Wi-Fi#cite_note-1https://en.wikipedia.org/wiki/Wireless_LANhttps://en.wikipedia.org/wiki/Interoperabilityhttps://en.wikipedia.org/wiki/Smartphonehttps://en.wikipedia.org/wiki/Tablet_computerhttps://en.wikipedia.org/wiki/Wireless_access_pointhttps://en.wikipedia.org/wiki/Hotspot_(Wi-Fi)https://en.wikipedia.org/wiki/Ethernethttps://en.wikipedia.org/wiki/Transport_Layer_Securityhttps://en.wikipedia.org/wiki/Wireless_LAN


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access can easily &e detected &y intruders. 8ecause o+ this, ii has adopted

various encryptiontechnologies. 'he early encryption /9proved easy to &reak. Higher 6uality

protocols (9*, 9*2) were added later. *n optional +eature added in 2:, called ii 9rotected

#etup(9#), had a serious +law that allowed an attacker to recover the router0s password. 'he i

i *lliance has since updated its test plan and certi+ication program to ensure all newly certi+ieddevices resist attacks.

History

$n 1;:1,*-


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controversy. 5#$>< won a +urther D22 million settlement +or ii patentin+ringements in 212 with

glo&al +irms in the United #tates re6uired to pay the 5#$>< licensing rights estimated to &e worth an

additional D1 &illion in royalties.

The name 'Wi-Fi'

'he term Wi-Fi, commercially used at least as early as *ugust 1;;;, was coined &y &randconsulting

+irm$nter&rand5orporation. 'he ii *lliance had hired $nter&rand to determine a name that was a

little catchier than 0$/// 2.11& 7irect #e6uence0. 9hil 8elanger, a +ounding mem&er o+ the ii

*lliance who presided over the selection o+ the name ii, also stated that $nter&rand

invented Wi-Fias a play on wordswith hi-fi, and also created the ii logo.

'he ii *lliance used the nonsense advertising slogan'he #tandard +or ireless idelity +or ashort time a+ter the &rand name was invented, leading to the misconception that ii was an

a&&reviation o+ ireless idelity. 'heyinyangii logo indicates the certi+ication o+ a product

+or interopera&ility.

onii technologies intended +or +iBed points, such as%otorola 5anopy, are usually descri&ed

as +iBed wireless. *lternative wireless technologies include mo&ile phone standards, such

as 2A, EA,4Aor -'/.

'he name is o+ten written as WiFior Wifi, &ut these are not approved &y the ii *lliance.

Wi-Fi certification

'he $///does not test e6uipment +or compliance with their standards. 'he nonpro+itii *lliance

was +ormed in 1;;; to +ill this void F to esta&lish and en+orce standards +or interopera&ility

and&ackward compati&ility, and to promotewirelesslocalareanetwork technology. *s o+ 21, the

ii *lliance consisted o+ more than E:! companies +rom around the world. 'he ii *lliance

en+orces the use o+ the ii &rand to technologies &ased on the $/// 2.11standards +rom the

$///. 'his includes wireless local area network(-*) connections, device to device connectivity

(such as ii 9eer to 9eer aka ii 7irect), 9ersonal area network(9*),local area

network(-*) and even some limited wide area network(*) connections. %anu+acturers with
https://en.wikipedia.org/wiki/Interbrandhttps://en.wikipedia.org/wiki/Interbrandhttps://en.wikipedia.org/wiki/Interbrandhttps://en.wikipedia.org/wiki/Punhttps://en.wikipedia.org/wiki/High_fidelityhttps://en.wikipedia.org/wiki/Advertising_sloganhttps://en.wikipedia.org/wiki/Advertising_sloganhttps://en.wikipedia.org/wiki/Yin_and_yanghttps://en.wikipedia.org/wiki/Yin_and_yanghttps://en.wikipedia.org/wiki/Yin_and_yanghttps://en.wikipedia.org/wiki/Interoperabilityhttps://en.wikipedia.org/wiki/Motorola_Canopyhttps://en.wikipedia.org/wiki/Motorola_Canopyhttps://en.wikipedia.org/wiki/Fixed_wirelesshttps://en.wikipedia.org/wiki/2Ghttps://en.wikipedia.org/wiki/3Ghttps://en.wikipedia.org/wiki/4Ghttps://en.wikipedia.org/wiki/4Ghttps://en.wikipedia.org/wiki/LTE_(telecommunication)https://en.wikipedia.org/wiki/LTE_(telecommunication)https://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineershttps://en.wikipedia.org/wiki/Non-profithttps://en.wikipedia.org/wiki/Non-profithttps://en.wikipedia.org/wiki/Backward_compatibilityhttps://en.wikipedia.org/wiki/Backward_compatibilityhttps://en.wikipedia.org/wiki/Wirelesshttps://en.wikipedia.org/wiki/Wirelesshttps://en.wikipedia.org/wiki/IEEE_802.11https://en.wikipedia.org/wiki/IEEE_802.11https://en.wikipedia.org/wiki/Wireless_LANhttps://en.wikipedia.org/wiki/Wi-Fi_Directhttps://en.wikipedia.org/wiki/Personal_area_networkhttps://en.wikipedia.org/wiki/Local_area_networkhttps://en.wikipedia.org/wiki/Local_area_networkhttps://en.wikipedia.org/wiki/Local_area_networkhttps://en.wikipedia.org/wiki/Wide_area_networkhttps://en.wikipedia.org/wiki/Wide_area_networkhttps://en.wikipedia.org/wiki/Interbrandhttps://en.wikipedia.org/wiki/Punhttps://en.wikipedia.org/wiki/High_fidelityhttps://en.wikipedia.org/wiki/Advertising_sloganhttps://en.wikipedia.org/wiki/Yin_and_yanghttps://en.wikipedia.org/wiki/Interoperabilityhttps://en.wikipedia.org/wiki/Motorola_Canopyhttps://en.wikipedia.org/wiki/Fixed_wirelesshttps://en.wikipedia.org/wiki/2Ghttps://en.wikipedia.org/wiki/3Ghttps://en.wikipedia.org/wiki/4Ghttps://en.wikipedia.org/wiki/LTE_(telecommunication)https://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineershttps://en.wikipedia.org/wiki/Non-profithttps://en.wikipedia.org/wiki/Backward_compatibilityhttps://en.wikipedia.org/wiki/Wirelesshttps://en.wikipedia.org/wiki/IEEE_802.11https://en.wikipedia.org/wiki/Wireless_LANhttps://en.wikipedia.org/wiki/Wi-Fi_Directhttps://en.wikipedia.org/wiki/Personal_area_networkhttps://en.wikipedia.org/wiki/Local_area_networkhttps://en.wikipedia.org/wiki/Local_area_networkhttps://en.wikipedia.org/wiki/Wide_area_network


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mem&ership in the ii *lliance, whose products pass the certi+ication process, gain the right to

mark those products with the ii logo.

#peci+ically, the certi+ication process re6uires con+ormance to the $/// 2.11 radio standards,

the9* and 9*2security standards, and the /*9authentication standard. 5erti+ication mayoptionally include tests o+ $/// 2.11 dra+t standards, interaction with cellularphone technology in

converged devices, and +eatures relating to security setup, multimedia, and powersaving.

ot every ii device is su&mitted +or certi+ication. 'he lack o+ ii certi+ication does not

necessarily imply that a device is incompati&le with other ii devices. $+ it is compliant or partly

compati&le, the ii *lliance may not o&=ect to its description as a ii device though technically

only certi+ied devices are approved. 'he ii *lliance may or may not sanction derivative terms,

such as #uper ii, coined &y the U# ederal 5ommunications 5ommission(55) to descri&e

proposed networking in the UH 'G &and in the U#.

IEEE 802.11 standard

'he $/// 2.11 standard is a set o+ media access control(%*5) and physical layer(9H)

speci+ications +or implementingwireless local area network(-*) computer communication in the

2.4,E.", !, and " AHz+re6uency &ands. 'hey are created and maintained &y

the$///-*C%*#tandards 5ommittee ($/// 2). 'he &ase version o+ the standard was

released in 1;;:, and has had su&se6uent amendments. 'he standard and amendments provide

the &asis +or wireless network products using the ii &rand. hile each amendment is o++icially

revoked when it is incorporated in the latest version o+ the standard, the corporate world tends to

market to the revisions &ecause they concisely denote capa&ilities o+ their products. *s a result, in

the market place, each revision tends to &ecome its own standard.

'he -inksys>'!4Acontains a router with an 2.11&Cg radio (common in the early 2s) and two antennas
https://en.wikipedia.org/wiki/Wi-Fi_Protected_Accesshttps://en.wikipedia.org/wiki/Wi-Fi_Protected_Accesshttps://en.wikipedia.org/wiki/Wi-Fi_Protected_Accesshttps://en.wikipedia.org/wiki/Extensible_Authentication_Protocolhttps://en.wikipedia.org/wiki/Extensible_Authentication_Protocolhttps://en.wikipedia.org/wiki/Super_Wi-Fihttps://en.wikipedia.org/wiki/Federal_Communications_Commissionhttps://en.wikipedia.org/wiki/Media_access_controlhttps://en.wikipedia.org/wiki/Media_access_controlhttps://en.wikipedia.org/wiki/Physical_layerhttps://en.wikipedia.org/wiki/Wireless_LANhttps://en.wikipedia.org/wiki/Wireless_LANhttps://en.wikipedia.org/wiki/IEEE_802.11y-2008https://en.wikipedia.org/wiki/IEEE_802.11y-2008https://en.wikipedia.org/wiki/IEEE_802.11adhttps://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineershttps://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineershttps://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineershttps://en.wikipedia.org/wiki/Local_area_networkhttps://en.wikipedia.org/wiki/Metropolitan_area_networkhttps://en.wikipedia.org/wiki/IEEE_802https://en.wikipedia.org/wiki/Linksyshttps://en.wikipedia.org/wiki/WRT54Ghttps://en.wikipedia.org/wiki/WRT54Ghttps://en.wikipedia.org/wiki/Wi-Fi_Protected_Accesshttps://en.wikipedia.org/wiki/Extensible_Authentication_Protocolhttps://en.wikipedia.org/wiki/Super_Wi-Fihttps://en.wikipedia.org/wiki/Federal_Communications_Commissionhttps://en.wikipedia.org/wiki/Media_access_controlhttps://en.wikipedia.org/wiki/Physical_layerhttps://en.wikipedia.org/wiki/Wireless_LANhttps://en.wikipedia.org/wiki/IEEE_802.11y-2008https://en.wikipedia.org/wiki/IEEE_802.11adhttps://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineershttps://en.wikipedia.org/wiki/Local_area_networkhttps://en.wikipedia.org/wiki/Metropolitan_area_networkhttps://en.wikipedia.org/wiki/IEEE_802https://en.wikipedia.org/wiki/Linksyshttps://en.wikipedia.org/wiki/WRT54G


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Uses

'o connect to a ii -*, a computer has to &e e6uipped with a wireless network inter+ace

controller.'he com&ination o+ computer and inter+ace controller is called a station. or all stations

that share a single radio +re6uency communication channel, transmissions on this channel are

received &y all stations within range. 'he transmission is not guaranteed to &e delivered and is

there+ore a &este++ort deliverymechanism. * carrier wave is used to transmit the data. 'he data is

organised in packets, re+erred to as /thernet +rames.

Internet access

ii technology may &e used to provide $nternet accessto devices that are within the range o+

a wireless networkthat is connected to the $nternet. 'he coverage o+ one or moreinterconnected access points(hotspots) can eBtend +rom an area as small as a +ew rooms to as

large as many s6uare kilometres. 5overage in the larger area may re6uire a group o+ access points

with overlapping coverage. or eBample, pu&lic outdoor ii technology has &een used

success+ully inwireless mesh networksin -ondon, UI. *n international eBample is


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ii also connects places that normally don0t have network access, such as kitchens and garden

sheds.

Wi-Fi radio spectrum

2.11& and 2.11g use the 2.4AHz$#% &and,operating in the United #tates under 9art 1!>ules

and >egulations. 8ecause o+ this choice o+ +re6uency &and, 2.11& and g e6uipment may

occasionally su++er inter+erence+rommicrowave ovens, cordless telephones, and 8luetoothdevices.

#pectrum assignments and operational limitations are not consistent worldwideK *ustralia and

/urope allow +or an additional two channels &eyond the 11 permitted in the United #tates +or the

2.4 AHz &and (1L1E), while @apan has three more (1L14). $n the U# and other countries, 2.11a

and 2.11g devices may &e operated without a license, as allowed in 9art 1! o+ the 55 >ules and>egulations.

* ii signal occupies +ive channels in the 2.4 AHz &and. *ny two channel num&ers that di++er &y

+ive or more, such as 2 and :, do not overlap. 'he o+trepeated adage that channels 1, ", and 11 are

the onlynonoverlapping channels is, there+ore, not accurate. 5hannels 1, ", and 11 are the

only group of threenonoverlapping channels in orth *merica and the United Iingdom. $n /urope

and @apan using 5hannels 1, !, ;, and 1E +or2.11gand 2.11nis recommended.

2.11a uses the ! AHz U$$ &and, which, +or much o+ the world, o++ers at least 2E nonoverlapping

channels rather than the 2.4 AHz $#% +re6uency &and, where ad=acent channels overlap.

Interference

ii connections can &e disrupted or the internet speed lowered &y having other devices in the

same area. %any 2.4 AHz 2.11& and 2.11gaccesspoints de+ault to the same channel on initial

startup, contri&uting to congestion on certain channels. ii pollution, or an eBcessive num&er o+access points in the area, especially on the neigh&oring channel, can prevent access and inter+ere

with other devices0 use o+ other access points, caused &y overlapping channels in the 2.11gC&

spectrum, as well as with decreasedsignaltonoise ratio(#>) &etween access points. 'his can

&ecome a pro&lem in highdensity areas, such as large apartment compleBes or o++ice &uildings with

many ii access points. $t is advised to only use channel 1"11.
https://en.wikipedia.org/wiki/Hertzhttps://en.wikipedia.org/wiki/Hertzhttps://en.wikipedia.org/wiki/ISM_bandhttps://en.wikipedia.org/wiki/ISM_bandhttps://en.wikipedia.org/wiki/ISM_bandhttps://en.wikipedia.org/wiki/Part_15_(FCC_rules)https://en.wikipedia.org/wiki/Interference_(communication)https://en.wikipedia.org/wiki/Microwave_ovenhttps://en.wikipedia.org/wiki/Microwave_ovenhttps://en.wikipedia.org/wiki/Cordless_telephonehttps://en.wikipedia.org/wiki/Bluetoothhttps://en.wikipedia.org/wiki/Bluetoothhttps://en.wikipedia.org/wiki/IEEE_802.11#802.11ghttps://en.wikipedia.org/wiki/IEEE_802.11#802.11ghttps://en.wikipedia.org/wiki/IEEE_802.11#802.11nhttps://en.wikipedia.org/wiki/IEEE_802.11#802.11nhttps://en.wikipedia.org/wiki/IEEE_802.11#Channels_and_international_compatibilityhttps://en.wikipedia.org/wiki/U-NIIhttps://en.wikipedia.org/wiki/IEEE_802.11#802.11ghttps://en.wikipedia.org/wiki/IEEE_802.11#802.11ghttps://en.wikipedia.org/wiki/Signal-to-noise_ratiohttps://en.wikipedia.org/wiki/Signal-to-noise_ratiohttps://en.wikipedia.org/wiki/Hertzhttps://en.wikipedia.org/wiki/ISM_bandhttps://en.wikipedia.org/wiki/Part_15_(FCC_rules)https://en.wikipedia.org/wiki/Interference_(communication)https://en.wikipedia.org/wiki/Microwave_ovenhttps://en.wikipedia.org/wiki/Cordless_telephonehttps://en.wikipedia.org/wiki/Bluetoothhttps://en.wikipedia.org/wiki/IEEE_802.11#802.11ghttps://en.wikipedia.org/wiki/IEEE_802.11#802.11nhttps://en.wikipedia.org/wiki/IEEE_802.11#Channels_and_international_compatibilityhttps://en.wikipedia.org/wiki/U-NIIhttps://en.wikipedia.org/wiki/IEEE_802.11#802.11ghttps://en.wikipedia.org/wiki/Signal-to-noise_ratio


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*dditionally, other devices use the 2.4 AHz &andK microwave ovens, $#% &anddevices, security

cameras, Mig8eedevices, 8luetoothdevices,video senders, cordless phones,&a&y monitors,and (in

some countries)*mateur radioall o+ which can cause signi+icant additional inter+erence. $t is also an

issue when municipalities or other large entities (such as universities) seek to provide large area

coverage.

Service set identifier (SSI!

$n addition to running on di++erent channels, multiple ii networks can share channels.

* service setis the set o+ all the devices associated with a particular ii network. 'he service set

can &e local, independent, eBtended or mesh.

/ach service set has an associated identi+ier, the #ervice #et $denti+ier (##$7), which consists o+ E2

&ytes that identi+ies the particular network. 'he ##$7 is con+igured within the devices that areconsidered part o+ the network, and it is transmitted in the packets. >eceivers ignore wireless

packets +rom other networks with a di++erent ##$7.

"#rou$#put

*s the 2.11 speci+ications evolved to support higher throughput, the &andwidth re6uirements also

increased to support them. 2.11n uses dou&le the radio spectrumC&andwidth (4 %Hz) compared

to 2.11aor 2.11g (2 %Hz).'his means there can &e only one 2.11n network on the 2.4 AHz

&and at a given location, without inter+erence toC+rom other -* tra++ic. 2.11n can also &e set to

limit itsel+ to 2 %Hz &andwidth to prevent inter+erence in dense community.

%any newer consumer devices support the latest 2.11ac standard, which uses the ! AHz &and

eBclusively and is capa&le o+ multistation -* throughput o+ at least 1 giga&it per second.

*ccording to a study, devices with the 2.11ac speci+ication are eBpected to &e common &y 21!

with an estimated one &illion spread around the world.

Hard%are

ii allows cheaper deployment o+ local area networks(-*s). *lso spaces where ca&les cannot

&e run, such as outdoor areas and historical &uildings, can host wireless -*s.
https://en.wikipedia.org/wiki/ISM_bandhttps://en.wikipedia.org/wiki/ZigBeehttps://en.wikipedia.org/wiki/ZigBeehttps://en.wikipedia.org/wiki/Bluetoothhttps://en.wikipedia.org/wiki/Bluetoothhttps://en.wikipedia.org/wiki/Video_senderhttps://en.wikipedia.org/wiki/Video_senderhttps://en.wikipedia.org/wiki/Baby_monitorhttps://en.wikipedia.org/wiki/Baby_monitorhttps://en.wikipedia.org/wiki/Amateur_radiohttps://en.wikipedia.org/wiki/Service_set_(802.11_network)https://en.wikipedia.org/wiki/IEEE_802.11#802.11ahttps://en.wikipedia.org/wiki/Local_area_networkhttps://en.wikipedia.org/wiki/ISM_bandhttps://en.wikipedia.org/wiki/ZigBeehttps://en.wikipedia.org/wiki/Bluetoothhttps://en.wikipedia.org/wiki/Video_senderhttps://en.wikipedia.org/wiki/Baby_monitorhttps://en.wikipedia.org/wiki/Amateur_radiohttps://en.wikipedia.org/wiki/Service_set_(802.11_network)https://en.wikipedia.org/wiki/IEEE_802.11#802.11ahttps://en.wikipedia.org/wiki/Local_area_network


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%anu+acturers are &uilding wireless network adapters into most laptops. 'he price o+ chipsets+or i

i continues to drop, making it an economical networking option included in even more devices.

7i++erent competitive &rands o+ access points and client networkinter+aces can interoperate at a

&asic level o+ service. 9roducts designated as ii 5erti+ied &y the ii *lliance are&ackwardscompati&le. Unlike mo&ile phones, any standard ii device will work anywhere in the world.

Standard devices

*nem&edded>outer8oard112 withU.->#%*pigtail and >!2 mini 95$ii card widely used

&y wireless$nternet service providers ($#9s) in the 5zech >epu&lic

i7A/ EA L2.11n*ccess 9oint and U%'#CA#%Aateway in one device

*n*therosii dra+t adaptor with &uilt in 8luetoothon a #ony Gaio / series laptop
https://en.wikipedia.org/wiki/Chipsethttps://en.wikipedia.org/wiki/Backwards_compatiblehttps://en.wikipedia.org/wiki/Backwards_compatiblehttps://en.wikipedia.org/wiki/Backwards_compatiblehttps://en.wikipedia.org/wiki/Mobile_phonehttps://en.wikipedia.org/wiki/Embedded_systemhttps://en.wikipedia.org/wiki/Embedded_systemhttps://en.wikipedia.org/wiki/Embedded_systemhttps://en.wikipedia.org/wiki/MikroTik#RouterBOARDhttps://en.wikipedia.org/wiki/Hirose_U.FLhttps://en.wikipedia.org/wiki/SMA_connectorhttps://en.wikipedia.org/wiki/Conventional_PCIhttps://en.wikipedia.org/wiki/Wirelesshttps://en.wikipedia.org/wiki/Wireless_Internet_service_providerhttps://en.wikipedia.org/wiki/Czech_Republichttps://en.wikipedia.org/wiki/IEEE_802.11n-2009https://en.wikipedia.org/wiki/IEEE_802.11n-2009https://en.wikipedia.org/wiki/High-Speed_Downlink_Packet_Accesshttps://en.wikipedia.org/wiki/Atheroshttps://en.wikipedia.org/wiki/Atheroshttps://en.wikipedia.org/wiki/Bluetoothhttps://en.wikipedia.org/wiki/Bluetoothhttps://en.wikipedia.org/wiki/Chipsethttps://en.wikipedia.org/wiki/Backwards_compatiblehttps://en.wikipedia.org/wiki/Backwards_compatiblehttps://en.wikipedia.org/wiki/Mobile_phonehttps://en.wikipedia.org/wiki/Embedded_systemhttps://en.wikipedia.org/wiki/MikroTik#RouterBOARDhttps://en.wikipedia.org/wiki/Hirose_U.FLhttps://en.wikipedia.org/wiki/SMA_connectorhttps://en.wikipedia.org/wiki/Conventional_PCIhttps://en.wikipedia.org/wiki/Wirelesshttps://en.wikipedia.org/wiki/Wireless_Internet_service_providerhttps://en.wikipedia.org/wiki/Czech_Republichttps://en.wikipedia.org/wiki/IEEE_802.11n-2009https://en.wikipedia.org/wiki/High-Speed_Downlink_Packet_Accesshttps://en.wikipedia.org/wiki/Atheroshttps://en.wikipedia.org/wiki/Bluetooth


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U#8wireless adapter

* wireless access point(*9) connects a group o+ wireless devices to an ad=acent wired -*.*n

access point resem&les anetwork hu&, relaying data&etween connected wireless devices in

addition to a (usually) single connected wired device, most o+ten an /thernet hu& or switch, allowing

wireless devices to communicate with other wired devices.

ireless adaptersallow devices to connect to a wireless network. 'hese adapters connect to

devices using various eBternal or internal interconnects such as 95$, mini95$, U#8,/Bpress5ard,

5ard&us and 95 5ard.*s o+ 21, most newer laptop computers come e6uipped with &uilt in

internal adapters.

ireless routersintegrate a ireless *ccess 9oint, /thernet switch,and internal router +irmware

application that provides $9routing,*',and7#+orwarding through an integrated *inter+ace.

* wireless router allows wired and wireless /thernet -* devices to connect to a (usually) single

* device such as a ca&le modemor a 7#- modem. * wireless router allows all three devices,

mainly the access point and router, to &e con+igured through one central utility. 'his utility is usually

an integrated we& serverthat is accessi&le to wired and wireless -* clients and o+ten optionally to

* clients. 'his utility may also &e an application that is run on a computer, as is the case with as*pple0s*ir9ort, which is managed with the*ir9ort Utilityon %ac


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re6uirements, such as +or cases where &ut a single user with a ii e6uipped ta&let migrates

around the com&ined eBtended and noneBtended portions o+ the total connected network.

*dditionally, a wireless device connected to any o+ the repeaters in the chain will have a data

throughput that is also limited &y the weakest link eBisting in the chain &etween where the

connection originates and where the connection ends. etworks employing wireless eBtenders arealso more prone to degradation +rom inter+erence +rom neigh&oring access points that &order

portions o+ the eBtended network and that happen to occupy the same channel as the eBtended

network.

'he security standard, ii 9rotected #etup, allows em&edded devices with limited graphical user

inter+ace to connect to the $nternet with ease. ii 9rotected #etup has 2 con+igurationsK 'he 9ush

8utton con+iguration and the 9$ con+iguration. 'hese em&edded devices are also called 'he

$nternet o+ 'hings and are lowpower, &atteryoperated em&edded systems. * num&er o+ ii

manu+acturers design chips and modules +or em&edded ii, such as Aain#pan.

Embedded systems

/m&edded serialtoii module

$ncreasingly in the last +ew years (particularly as o+ 2:), em&edded ii modules have &ecome

availa&le that incorporate a realtime operating system and provide a simple means o+ wirelessly

ena&ling any device which has and communicates via a serial port. 'his allows the design o+ simple

monitoring devices. *n eBample is a porta&le /5A device monitoring a patient at home. 'his ii

ena&led device can communicate via the $nternet.

'hese ii modules are designed &y


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$n @une 214 'eBas $nstruments introduced the +irst *>% 5orteB%4 with an on&oard dedicated ii

%5U, the #imple-ink 55E2. 7evelopers are now a&le to design /m&edded systems to connect to

the $nternet o+ 'hings ($o') using a single chip.

&an$e

'he ii signal range depends on the +re6uency &and, radio power output, antenna gain and

antenna type as well as the modulation techni6ue. -ineo+sight is the thum&nail guide &ut re+lection

and re+raction can have a signi+icant impact.

*n access point compliant with either 2.11&or 2.11g,using the stock antenna might have a

range o+ 1 m (EE +t). 'he same radio with an eBternal semi para&olic antenna (1! d8 gain) might

have a range over 2 miles.

Higher gain rating (d8i) indicates +urther deviation (generally toward the horizontal) +rom a

theoretical, per+ect isotropic radiator, and there+ore the +urther the antenna can pro=ect a usa&le

signal, as compared to a similar output power on a more isotropic antenna. or eBample, an d8i

antenna used with a 1 m driver will have a similar horizontal range to a " d8i antenna &eing

driven at ! m. ote that this assumes that radiation in the vertical is lostJ this may not &e the

case in some situations, especially in large &uildings or within awaveguide. $n the a&ove eBample, a

directional waveguide could cause the low power " d8i antenna to pro=ect much +urther in a single

direction than the d8i antenna which is not in a waveguide, even i+ they are &oth &eing driven at

1 m.

$/// 2.11n, however, can more than dou&le the range.>ange also varies with +re6uency &and.

ii in the 2.4 AHz +re6uency &lock has slightly &etter range than ii in the ! AHz +re6uency

&lock used &y 2.11a (and optionally &y 2.11n).


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'o reach re6uirements +or wireless -* applications, ii has +airly high power consumption

compared to some other standards. 'echnologies such as 8luetooth(designed to support

wireless personal area network(9*) applications) provide a much shorter propagationrange

&etween 1 and 1 m and so in general have a lower power consumption.


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implementations have moved toward thin access points, with more o+ thenetwork

intelligencehoused in a centralized network appliance, relegating individual access points to the role

o+ dum& transceivers.


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ii 9rotected *ccessencryption (9*2) is considered secure, provided a strong passphraseis

used. * proposed modi+ication to 9*2 is 9*


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proiect 3.docx

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