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802.11 Protocol Stack and Physical Layer

Feb 11, 2018

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    Rafn` dg Cdit`its

    1. Afstractmdi

    6. Mitrdbuctmdi

    6.1 Dv`rvm`w

    6.6 [mr`n`ss Ndcan Ar`a I`twdre

    6.3 Rj` Fasmc Structur` dg a [mr`n`ss NAI

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    6.$ Rj` %&&& Sta!#ar#

    3. :

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    Afstractmdi

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    A!# as cd!cnusmd! w` wmnn sa= tjat wmr`n`ss !`twdrem!" jas a rdomsm!" gutur` wmtj

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    Rj` *asmc Structur` dg a (mr`n`ss A)

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    Cd+,armi- a (mr`n`ss A) td a (mr`b )`t'dre

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    [NAIs t=mcann= us` tj` u!nmc`!s`# %!#ustrman9 Scm`!tmgmc9 a!# 7`#mcan (%S7) ra#mdgr`5u`!c= a!#s. %! tj` !mt`# Stat`s9 tj` %S7 a!#s m!cnu#` tj` >+7; a!# (>6B>6u`icy =d,,mi- S,r`ab S,`ctru+ /5=SS

    %! 8;SS tj` tdtan gr`5u`!c= a!# ms snmt m!td a !uo`r dg cja!!`ns. Rj` rda#cast #ata ms sr`a#acrdss tj` `!tmr` gr`5u`!c= a!# = jdm!" `tw``! tj` cja!!`ns m! a s`u#d ra!#do gasjmd!.

    8r`5u`!c=+jdm!" sr`a# s`ctruo (8;SS) ms a sr`a#+s`ctruoo`tjd# dg tra!somttm!" ra#mdsm"!ans = ram#n= swmtcjm!" a carrm`raod!" oa!= gr`5u`!c= cja!!`ns9 usm!" as`u#dra!#dos`5u`!c` e!dw! td dtj tra!somtt`r a!# r`c`mv`r.A sr`a#+s`ctruo tra!somssmd! dgg`rs tjr`` oam! a#va!ta"`s dv`r a gm-`#+gr`5u`!c=tra!somssmd!*Sr`a#+s`ctruo sm"!ans ar` jm"jn= r`smsta!t td !dms`a!# m!t`rg`r`!c`.Rj` rdc`ss dg r`+cdnn`ctm!" a sr`a# sm"!an sr`a#s dut !dms` a!# m!t`rg`r`!c`9 causm!" tj`o td r`c`#` m!td tj`ace"rdu!#.Sr`a#+s`ctruo sm"!ans ar` #mggmcunt td m!t`rc`t. A 8r`5u`!c=+;d sr`a#+s`ctruo sm"!ansdu!#s nme` a odo`!tar= !dms` urst dr smon= a! m!cr`as` m! tj` ace"rdu!# !dms` gdr sjdrt8r`5u`!c=+;d cd#`s d! a!= !arrdwa!# r`c`mv`r `-c`t a 8r`5u`!c=+;d sr`a#+s`ctruo

    r`c`mv`r usm!" tj` `-act sao` cja!!`n s`5u`!c` as was us`# = tj` tra!somtt`r.Sr`a#+s`ctruo tra!somssmd!s ca! sjar` a gr`5u`!c= a!# wmtj oa!= t=`s dg cd!v`!tmd!antra!somssmd!s wmtj om!moan m!t`rg`r`!c`. Rj` sr`a#+s`ctruo sm"!ans a## om!moan !dms` td tj`!arrdw+gr`5u`!c= cdoou!mcatmd!s9 a!# vmc` v`rsa. As a r`sunt9 a!#wm#tj ca! ` utmnm`# odr``ggmcm`!tn=.

    8r`5u`!c= ;dm!" utmnm`s a s`t dg !arrdw cja!!`ns a!# OjdsO tjrdu"j ann dg tj`o m! ar`#`t`rom!`# s`5u`!c`. 8dr `-aon`9 tj` 6.2 L; gr`5u`!c= a!# ms #mvm#`# m!td cja!!`nsdg 1 7; `acj. &v`r= 6 td 2 os`c tj` s=st`o OjdsO td a !`w cja!!`n gdnndwm!" ar`#`t`rom!`# c=cnmc att`r!.Rj`

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    Rj` 8;SS tra!somtt`r ms a s`u#d+!dms` 'I cd#` cd!trdnn`# gr`5u`!c= s=!tj`sm`r. Rj`m!sta!ta!`dus gr`5u`!c= dutut dg tj` tra!somtt`r ?uos grdo d!` vanu` td a!dtj`r as`# d! tj`s`u#d+ra!#do m!ut grdo tj` cd#` "`!`ratdr. 4ar=m!" tj` m!sta!ta!`dus gr`5u`!c= r`sunts m! a!dutut s`ctruo tjat ms `gg`ctmv`n= sr`a# dv`r tj` ra!"` dg gr`5u`!cm`s "`!`rat`#.

    8m".1 8;SS S`ctruo

    %! tjms s=st`o9 tj` !uo`r dg #mscr`t` gr`5u`!cm`s #`t`rom!`s tj` a!#wm#tj dg tj`s=st`o. ;`!c`9 tj` rdc`ss "am! ms #mr`ctn= #``!#`!t d! tj` !uo`r dg avamnan gr`5u`!c=cjdmc`s gdr a "mv`! m!gdroatmd! rat`.A!dtj`r modrta!t gactdr m! 8;SS s=st`os ms tj` rat` at wjmcj tj` jds dccur. Rj` om!mouotmo` r`5umr`# td cja!"` gr`5u`!cm`s ms #``!#`!t d! tj` m!gdroatmd! mt rat`9 tj` aodu!t dgr`#u!#a!c= us`#9 a!# tj` #msta!c` td tj` !`ar`st m!t`rg`r`!c` sdurc`.

    mr`ct S`>u`ic` S,r`ab S,`ctru+ /SSS

    /mr`ct S`5u`!c` Sr`a# S`ctruo ms as`# d! tj` ountmn=m!" dg tj` as`a!# sm"!an #ata wmtj arda#a!# sr`a#m!" cd#`. Rj` r`sunt ms t`ro`# tj` cjm rat`. Rj` cjaract`rmstmcs dg tj`rda#a!# sr`a#m!" cd#` ar` tjat dg s`u#dra!#do !dms`. Cd!s`5u`!tn= tj` r`c`mv`rs=!cjrd!m`# td tj` cd#` wmnn dtam! tj` !arrdwa!# sm"!an. Ann dtj`r r`c`mv`rs wmnn s`` tj`sr`a# sm"!an as wjmt` dr cdndr`# !dms`.%! cd!trast9 gr`5u`!c=+jdm!" sr`a# s`ctruos`u#d+ra!#don= r`tu!`s tj` carrm`r9 m!st`a# dga##m!" s`u#d+ra!#do !dms` td tj` #ata9 wjmcj r`sunts m! a u!mgdro gr`5u`!c= #mstrmutmd! wjds`wm#tj ms #`t`rom!`# = tj` dutut ra!"` dg tj`s`u#d+ra!#do!uo`r "`!`ratdr.%! t`n`cdoou!mcatmd!s9 #mr`ct+s`5u`!c` sr`a# s`ctruo ms aod#unatmd! t`cj!m5u` wj`r` tj`tra!somtt`# sm"!an tae`s u odr`a!#wm#tjtja! tj` m!gdroatmd! sm"!an tjat ms `m!" od#unat`#9

    wjmcj ms tj` r`asd! tjat mt ms cann`#sr`a# s`ctruo. /SSS jas tj` gdnndwm!" g`atur`s*gdr "`!`ratm!" sr`a#+s`ctruo tra!somssmd!s =jas`+od#unatm!" asm!` wav`s`u#d ra!#don=wmtj a cd!tm!udus strm!"dgs`u#d !dms`cd#`s=odns9 `acj dg #uratmd! oucj soann`r tja! amt.A sm"!an structurm!" t`cj!m5u` utmnmm!" a #m"mtancd#`s`5u`!c`('I S`5u`!c`s) javm!" acjmrat`oucj jm"j`r tja! tj` m!gdroatmd! sm"!anmt rat`. &acj m!gdroatmd! mt dg a #m"mtan sm"!anmstra!somtt`# as a s`u#dra!#do s`5u`!c` dg cjms.

    32

    http://en.wikipedia.org/wiki/Frequency-hopping_spread_spectrumhttp://en.wikipedia.org/wiki/Pseudo-random_numberhttp://en.wikipedia.org/wiki/Telecommunicationhttp://en.wikipedia.org/wiki/Modulationhttp://en.wikipedia.org/wiki/Bandwidthhttp://en.wikipedia.org/wiki/Spread_spectrumhttp://en.wikipedia.org/wiki/Phase_modulationhttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Pseudorandomhttp://en.wikipedia.org/wiki/String_(computer_science)http://en.wikipedia.org/wiki/Pseudonoisehttp://en.wikipedia.org/wiki/Codehttp://en.wikipedia.org/wiki/Bithttp://en.wikipedia.org/wiki/Signaling_(telecommunication)http://en.wikipedia.org/wiki/Digitalhttp://en.wikipedia.org/wiki/Sequencehttp://en.wikipedia.org/wiki/PN_Sequenceshttp://en.wikipedia.org/wiki/Chip_ratehttp://en.wikipedia.org/wiki/Chip_ratehttp://en.wikipedia.org/wiki/Informationhttp://en.wikipedia.org/wiki/Bit_ratehttp://en.wikipedia.org/wiki/Digital_signalhttp://en.wikipedia.org/wiki/Frequency-hopping_spread_spectrumhttp://en.wikipedia.org/wiki/Pseudo-random_numberhttp://en.wikipedia.org/wiki/Telecommunicationhttp://en.wikipedia.org/wiki/Modulationhttp://en.wikipedia.org/wiki/Bandwidthhttp://en.wikipedia.org/wiki/Spread_spectrumhttp://en.wikipedia.org/wiki/Phase_modulationhttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Pseudorandomhttp://en.wikipedia.org/wiki/String_(computer_science)http://en.wikipedia.org/wiki/Pseudonoisehttp://en.wikipedia.org/wiki/Codehttp://en.wikipedia.org/wiki/Bithttp://en.wikipedia.org/wiki/Signaling_(telecommunication)http://en.wikipedia.org/wiki/Digitalhttp://en.wikipedia.org/wiki/Sequencehttp://en.wikipedia.org/wiki/PN_Sequenceshttp://en.wikipedia.org/wiki/Chip_ratehttp://en.wikipedia.org/wiki/Chip_ratehttp://en.wikipedia.org/wiki/Informationhttp://en.wikipedia.org/wiki/Bit_ratehttp://en.wikipedia.org/wiki/Digital_signal
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    Rj` rm!cmn` dgmr`ct S`qu`ic`ms td sr`a# a sm"!an d! a nar"`r gr`5u`!c= a!# = ountmn`-m!"mt wmtj a sm"!atur` dr cd#` td om!mom` ndcanm`# m!t`rg`r`!c` a!# ace"rdu!# !dms`. Rd sr`a#tj` sm"!an9 `acj mt ms od#unat`# = a cd#`. %! tj` r`c`mv`r9 tj` drm"m!an sm"!an ms r`cdv`r`# =r`c`mvm!" tj` wjdn` sr`a# cja!!`n a!# #`od#unatm!" wmtj tj` sao` cd#` us`# = tj`tra!somtt`r. Rj`

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    8m". 1 F'S /SSS S`ctruoRj` a!#wm#tj m! /SSS s=st`os ms dgt`! tae`! as tj` !unn+td+!unn a!#wm#tj dg tj` oam! nd` dgtj` dw`r s`ctran #`!smt= ndt (m!#mcat`# as 6:c m! 8m". 1). Rj` jang dw`r a!#wm#tj dg tjmsnd` ms 1.6 :c9 wj`r` :c ms tj` cjm rat`. Rj`r`gdr`9 tj` a!#wm#tj dg a /SSS s=st`o ms a #mr ctgu!ctmd! dg tj` cjm rat`K s`cmgmcann= 6:c0:%I8D. Rjms ms ?ust a! `-t`!smd! dg tj` r`vmdus`5uatmd! gdr rdc`ss "am!. %t sjdun# ` !dt`# tjat tj` dw`r cd!tam!`# m! tj` oam! nd`cdorms`s > `rc`!t dg tj` tdtan dw`r. Rjms anndws a !arrdw`r :8 a!#wm#tj td accdood#at`tj` r`c`mv`# sm"!an wmtj tj` `gg`ct dg rdu!#m!" tj` r`c`mv`# uns`s m! tj` tmo` #doam!.D!` g`atur` dg /SSS ms tjat 'S oa= ` us`# td m!cr`as` tj` #ata rat`. Rjms m!cr`as` dg agactdr dg twd mts `r s=odn dg tra!somtt`# m!gdroatmd! dv`r F'S caus`s a! `5umvan`!tr`#uctmd! m! tj` avamnan` rdc`ss "am!. Rj` rdc`ss "am! ms r #uc`# `caus` gdr a "mv`! cjmrat`9 tj` a!#wm#tj (wjmcj s`ts tj` rdc`ss "am!) ms janv`# #u` td tj` twd+gdn# m!cr`as` m!m!gdroatmd! tra!sg`r. Rj` r`sunt ms tjat s=st`os m! a s`ctrann= 5um`t `!vmrd!o`!t `!`gmt grdo tj`dssmn` m!cr`as` m! #ata tra!sg`r rat`.

    SSS dbunatmdi

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    twd #ata mts. Rjms ms a cn`v`r rdc`ss tjat `!an`s tj` #ata str`ao td ` s`!t at 67s wjmn`usm!" tj` sao` aodu!t dg a!#wm#tj as tj` d!` s`!t at 17s. Rj` od#unatdr us`s smomnaro`tjd#s gdr tj` jm"j`r9 $.$7s a!# 117s #ata rat`s.

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    Rrais+mt 5r`>u`icm`s

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    Cja!!`n 8r`5u`!c= (L;)1 6.2166 6.213 6.2662 6.26$ 6.236, 6.23 6.226< 6.22> 6.2$6

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    Rj` su+carrm`rs ar` drtjd"d!an9 sd `acj ca! ` r`c`mv`# wmtjdut m!t`rg`r`!c` grdo a!dtj`r.

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    A odr` o`a!m!"gun o`tjd# gdr vm`wm!" D8/7 sm"!an dw`r cjaract`rmstmcs us`s tj`cdon`o`!tar= cuounatmv` #mstrmutmd! gu!ctmd! (CC/8). Rjms o`trmc nm!es a `rc`!ta"`rdamnmt= td a dw`r n`v`n. %! tjms o`asur`o`!t9 a! m!struo`!t wmtj tmo`+"atm!" caamnmt= msus`# td s`n`ct d!n= tj` actmv` drtmd! dg tj` urst (s`` 8m"ur` 6 ndw`r trac`).%g tmo` "atm!" w`r` !dt us`#9 tj` `rmd#s wj`! tj` urst ms dgg wdun# r`#uc` tj` av`ra"` dw`r

    cancunatmd!. Rj` CC/89 wjmcj ms smon= tj` odr` cdood! cuounatmv` #mstrmutmd! gu!ctmd!(C/8) sutract`# grdo 1.9 sjdws tj` !uo`r dg #`cm`ns adv` tj` av`ra"` dw`r d! tj`jdrmd!tan a-ms9 a!# `rc`!t rdamnmt= d! v`rtmcan a-ms (s`` 8m"ur` 6 u`r trac`). A CC/8o`asur`o`!t wdun# ` oa#` dv`r s`v`ran ursts td mordv` tj` accurac= dg tj` o`asur`o`!t.

    Rj` M :1>9 ms a! `-t`!smd! dg tj`

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    a#`5uat`n= cjaract`rm` tj` :8 `!vmrd!o`!t dg tj` rdds`# wmr`n`ss !`twdre m! t`ros dg ra!"`9cja!!`n m!t`rg`r`!c` a!# #`na= sr`a#.%t wdun# ` u!r`anmstmc td `-`ct td r`anm` tj` gunn #ata rat` caamnmt= ($2 70s) dg

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    jm"j`r #ata+tra!somssmd! rat`s9 tj` %&&& r`c`!tn= ratmgm`# tj`

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    Affr`#matmdi

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    [&' + [mr`# &5umvan`!t 'rmvac=IA4 + I`twdre Anndcatmd! 4`ctdrC:C + C=cnmc :`#u!#a!c= Cj`ce%&&&+SA + %!stmtut` dg &n`ctrmcan a!# &n`ctrd!mcs &!"m!``rs Sta!#ar#s Assdcmatmd!&47 + &rrdr 4`ctdr 7a"!mtu#`CC + cdon`o`!tar= cd#` e`=m!"C/8 + Cuounatmv` /mstrmutmd! 8u!ctmd!CC/8 + Cdon`o`!tar= Cuounatmv` /mstrmutmd! 8u!ctmd!8&C + 8drwar# &rrdr Cdrr`ctmd!A7/'S + /mgg`r`!tmanua#ratur` 'jas` Sjmgt `=m!"

    /F'S + /mgg`r`!tman Fm!ar= 'jas` Sjmgt `=m!"'I B 's`u#d Idms`:8 B :a#md 8r`5u`!c=D8/7 + Drtjd"d!an 8r`5u`!c= /mvmsmd! 7untmn`-m!"88C + 8`#`ran Cdoou!mcatmd!s Cdoomssmd!/SSS + /mr`ct S`5u`!c` Sr`a# S`ctruo8;SS + 8r`5u`!c= ;dm!" Sr`a# S`ctruo''7 + 'uns` 'dsmtmd! 7d#unatmd!;:+/SSS + ;m"j :at` /mr`ct S`5u`!c` Sr`a# S`ctruo''/ + 'NC' 'rdtdcdn /ata !mt'7/ + 'j=smcan 7`#muo /``!#`!t

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    23

    http://searchenterprisevoice.techtarget.com/sDefinition/0,,sid66_gci213826,00.htmlhttp://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci1025328,00.htmlhttp://www.fcc.gov/http://searchenterprisevoice.techtarget.com/sDefinition/0,,sid66_gci213826,00.htmlhttp://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci1025328,00.htmlhttp://www.fcc.gov/
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