Kev Txhim Kho thiab Kev Sib Txawv ntawm 802.11a/b/g/n/ac
Txij li thaum thawj zaug tso tawm Wi-Fi rau cov neeg siv khoom hauv xyoo 1997, tus qauv Wi-Fi tau hloov pauv tas li, feem ntau nce qhov ceev thiab nthuav dav kev pabcuam. Raws li cov haujlwm tau ntxiv rau tus qauv IEEE 802.11 thawj, lawv tau hloov kho los ntawm nws cov kev hloov kho (802.11b, 802.11g, thiab lwm yam)
802.11b 2.4GHz
802.11b siv tib lub zaus 2.4 GHz li tus qauv 802.11 thawj. Nws txhawb nqa qhov ceev tshaj plaws ntawm 11 Mbps thiab ntau yam txog li 150 feet. Cov khoom siv 802.11b pheej yig, tab sis tus qauv no muaj qhov ceev tshaj plaws thiab qeeb tshaj plaws ntawm txhua tus qauv 802.11. Thiab vim 802.11b ua haujlwm ntawm 2.4 GHz, cov khoom siv hauv tsev lossis lwm yam 2.4 GHz Wi Fi network yuav ua rau muaj kev cuam tshuam.
802.11a 5GHz OFDM
Cov qauv kho dua tshiab "a" ntawm tus qauv no tau tso tawm tib lub sijhawm nrog 802.11b. Nws qhia txog cov thev naus laus zis nyuaj dua hu ua OFDM (Orthogonal Frequency Division Multiplexing) rau kev tsim cov teeb liab wireless. 802.11a muab qee qhov zoo dua li 802.11b: nws ua haujlwm hauv 5 GHz zaus band tsawg dua thiab yog li ntawd tsis tshua muaj kev cuam tshuam. Thiab nws cov bandwidth siab dua 802.11b, nrog rau qhov siab tshaj plaws theoretical ntawm 54 Mbps.
Tej zaum koj yuav tsis tau ntsib ntau yam khoom siv lossis routers 802.11a. Qhov no yog vim tias cov khoom siv 802.11b pheej yig dua thiab nrov zuj zus hauv kev lag luam. 802.11a feem ntau yog siv rau kev siv ua lag luam.
802.11g 2.4GHz OFDM
Tus qauv 802.11g siv tib lub thev naus laus zis OFDM li 802.11a. Ib yam li 802.11a, nws txhawb nqa qhov siab tshaj plaws theoretical ntawm 54 Mbps. Txawm li cas los xij, zoo li 802.11b, nws ua haujlwm hauv 2.4 GHz zaus congested (thiab yog li ntawd raug kev txom nyem los ntawm tib qho teeb meem cuam tshuam li 802.11b). 802.11g yog rov qab sib xws nrog 802.11b cov khoom siv: 802.11b cov khoom siv tuaj yeem txuas rau 802.11g access points (tab sis ntawm 802.11b ceev).
Nrog 802.11g, cov neeg siv khoom tau ua tiav qhov kev vam meej tseem ceeb hauv Wi-Fi qhov ceev thiab kev pabcuam. Lub caij no, piv rau cov tiam dhau los ntawm cov khoom, cov neeg siv khoom wireless routers tau zoo dua thiab zoo dua, nrog lub zog siab dua thiab kev pabcuam zoo dua.
802.11n (Wi-Fi 4) 2.4/5GHz MIMO
Nrog tus qauv 802.11n, Wi Fi tau ua haujlwm sai dua thiab txhim khu kev qha dua. Nws txhawb nqa qhov siab tshaj plaws theoretical kis tau tus nqi ntawm 300 Mbps (txog li 450 Mbps thaum siv peb lub antennas). 802.11n siv MIMO (Multiple Input Multiple Output), qhov twg ntau lub transmitters / receivers ua haujlwm tib lub sijhawm ntawm ib lossis ob qho kawg ntawm qhov txuas. Qhov no tuaj yeem ua rau cov ntaub ntawv ntau ntxiv yam tsis tas yuav muaj bandwidth lossis lub zog kis tau ntau dua. 802.11n tuaj yeem ua haujlwm hauv 2.4 GHz thiab 5 GHz zaus bands.
802.11ac (Wi-Fi 5) 5GHz MU-MIMO
802.11ac ua kom Wi Fi ceev dua, nrog rau qhov ceev ntawm 433 Mbps mus rau ntau gigabits ib ob. Yuav kom ua tiav qhov kev ua tau zoo no, 802.11ac tsuas yog ua haujlwm hauv 5 GHz zaus band, txhawb nqa txog yim qhov chaw ntws (piv rau plaub qhov dej ntws ntawm 802.11n), ob npaug ntawm qhov dav ntawm channel mus rau 80 MHz, thiab siv cov thev naus laus zis hu ua beamforming. Nrog beamforming, antennas tuaj yeem xa cov teeb liab xov tooj cua, yog li lawv ncaj qha taw tes rau cov khoom siv tshwj xeeb.
Lwm qhov kev nce qib tseem ceeb ntawm 802.11ac yog Multi User (MU-MIMO). Txawm hais tias MIMO coj ntau cov kwj mus rau ib tus neeg siv khoom, MU-MIMO tuaj yeem coj cov kwj mus rau ntau tus neeg siv khoom tib lub sijhawm. Txawm hais tias MU-MIMO tsis ua kom qhov ceev ntawm ib tus neeg siv khoom nce ntxiv, nws tuaj yeem txhim kho tag nrho cov ntaub ntawv xa mus ntawm tag nrho lub network.
Raws li koj tuaj yeem pom, Wi-Fi kev ua tau zoo txuas ntxiv mus, nrog rau qhov ceev thiab kev ua tau zoo ze rau qhov ceev ntawm cov xov hlau
802.11ax Wi-Fi 6
Xyoo 2018, WiFi Alliance tau siv cov kev ntsuas los ua kom cov npe txheem WiFi yooj yim dua rau kev lees paub thiab nkag siab. Lawv yuav hloov tus qauv 802.11ax uas yuav los txog rau WiFi6
Wi-Fi 6, 6 nyob qhov twg?
Cov ntsuas kev ua tau zoo ntawm Wi-Fi suav nrog qhov deb ntawm kev sib kis, tus nqi sib kis, lub peev xwm ntawm lub network, thiab lub roj teeb. Nrog rau kev txhim kho ntawm thev naus laus zis thiab lub sijhawm, tib neeg cov kev xav tau rau qhov ceev thiab bandwidth tau nce siab.
Muaj ntau yam teeb meem hauv kev sib txuas Wi-Fi ib txwm muaj, xws li kev sib tsoo ntawm lub network, kev pab me me, thiab qhov xav tau hloov SSID tas li.
Tab sis Wi Fi 6 yuav coj cov kev hloov pauv tshiab: nws ua kom zoo dua qhov kev siv hluav taws xob thiab kev pabcuam ntawm cov khoom siv, txhawb nqa ntau tus neeg siv ceev ceev, thiab tuaj yeem ua pov thawj kev ua tau zoo dua hauv cov xwm txheej siv ntau, thaum tseem coj kev sib kis ntev dua thiab cov nqi sib kis siab dua.
Zuag qhia tag nrho, piv rau nws cov neeg ua ntej, qhov zoo ntawm Wi Fi 6 yog "ob chav siab thiab ob chav qis":
Kev kub ceev: Ua tsaug rau kev qhia txog cov thev naus laus zis xws li uplink MU-MIMO, 1024QAM modulation, thiab 8 * 8MIMO, qhov ceev tshaj plaws ntawm Wi Fi 6 tuaj yeem ncav cuag 9.6Gbps, uas tau hais tias zoo ib yam li qhov ceev stroke.
Kev nkag mus tau zoo: Qhov kev txhim kho tseem ceeb tshaj plaws ntawm Wi Fi 6 yog kom txo qhov kev sib tsoo thiab tso cai rau ntau lub cuab yeej txuas rau lub network. Tam sim no, Wi Fi 5 tuaj yeem sib txuas lus nrog plaub lub cuab yeej tib lub sijhawm, thaum Wi Fi 6 yuav tso cai rau kev sib txuas lus nrog txog li ntau lub cuab yeej tib lub sijhawm. Wi Fi 6 kuj siv OFDMA (Orthogonal frequency-division multiple access) thiab ntau-channel signal beamforming technologies los ntawm 5G los txhim kho Spectral efficiency thiab network peev xwm feem.
Qis latency: Los ntawm kev siv cov thev naus laus zis xws li OFDMA thiab SpatialReuse, Wi Fi 6 ua rau ntau tus neeg siv xa xov xwm sib txuas lus hauv txhua lub sijhawm, tshem tawm qhov xav tau kev tos thiab tos, txo kev sib tw, txhim kho kev ua haujlwm zoo, thiab txo qis latency. Txij li 30ms rau Wi Fi 5 txog 20ms, nrog rau qhov nruab nrab latency txo qis ntawm 33%.
Kev siv hluav taws xob tsawg: TWT, lwm yam thev naus laus zis tshiab hauv Wi Fi 6, tso cai rau AP sib tham sib txuas lus nrog cov davhlau ya nyob twg, txo lub sijhawm xav tau los tswj kev xa xov thiab tshawb nrhiav cov teeb liab. Qhov no txhais tau tias txo kev siv roj teeb thiab txhim kho lub neej roj teeb, ua rau kev siv hluav taws xob ntawm cov davhlau ya nyob twg txo qis 30%.
Lub sijhawm tshaj tawm: Lub Xya Hli-12-2023
