AT&T 3G Network vs AT&T 4G Network
AT&T 3G thiab AT&T 4G yog ob qho tib si mobile broadband technologies siv los ntawm AT&T hauv Asmeskas. AT&T yog ib lub tuam txhab kev sib txuas lus hauv ntiaj teb. AT&T muaj qhov zoo tshaj plaws mobile broadband network thoob plaws lub tebchaws los ntawm kev siv cov thev naus laus zis sib txawv hauv GSM txoj hauv kev. Lawv tab tom tsiv mus rau qhov ceev tshaj plaws 4th Generation mobile technology LTE (Long Term Evolution) thiab xav kom Launch nws los ntawm Q3 2011. Tam sim no AT&T muaj HSPA + uas yog qib nkag 4G technologies thiab deb ntawm cov ntaub ntawv tus nqi zoo dua li HSPA. (nyeem qhov txawv ntawm HSPA thiab HSPA +). Cov thev naus laus zis AT&T tau siv, muab cov ntaub ntawv thiab lub suab ib txhij thiab txawm tias hauv 4G LTE lawv siv VoLTE (Suab tshaj LTE).
AT&T 3G Network
AT&T Mobility yog ib lub tuam txhab ua lag luam tag nrho rau AT&T uas muab kev pabcuam wireless hauv Tebchaws Meskas thiab muaj kwv yees li 96 lab tus neeg siv khoom. Lawv siv UMTS/HSPA thev naus laus zis rau lawv cov 3G network uas cov ntaub ntawv ntau dua tuaj yeem ua tau raws li tau teev tseg los ntawm ITU rau 3G tes hauj lwm. Feem ntau cov bandwidth yog siv rau Circuit Court hloov lub suab thiab multimedia daim ntawv thov xws li video qhia uas yog ib tug tswv cuab muab los ntawm AT&T. Nws yog ib qho tseem ceeb uas AT&T siv 850 MHz thiab 1900 MHz bands rau lawv 3G network xov tooj cua interface. Txoj kev tshawb fawb tsis ntev los no ntawm lub network tau qhia tias AT&T 3G network muaj peev xwm xa cov ntaub ntawv nruab nrab ntawm 1410 kbps downlink thiab 773 kbps uplink uas yog ua ntej ntawm lwm cov neeg sib tw xws li Verizon thiab T mobile. Nws yog ib qho tseem ceeb uas qhov kev ntseeg siab ntawm lub network suav nrog 94% uas tseem siab dua li cov neeg sib tw tam sim no.
AT&T kuj tseem nrov ntawm Apple iPhone, iPad cov neeg siv nrog nws qhov nruab nrab downlink ceev ntawm 1259 kbps thiab 215 uplink ntawm kbps uas yog tus nqi siab dua ntawm cov neeg sib tw. Nws yog ib qho tseem ceeb uas AT&T tau hloov 90% ntawm lawv 3G network rau HSUPA thaum kawg ntawm 2009.
AT&T 4G Network
4G yog cov tiam tom ntej rau kev sib txuas lus ntawm tes thiab AT&T xa ob HSPA + thiab LTE ua lawv cov thev naus laus zis loj hauv lawv 4G network. Tam sim no lawv tab tom muab HSPA + nrog rau kev hloov kho software rau lub network system, uas xav kom xa cov ntaub ntawv tus nqi plaub zaug dua li cov ntaub ntawv broadband tam sim no siab dua (4X Ceev dua HSPA). Cov kauj ruam tom ntej ntawm 4G yog LTE uas tau ua tiav thiab xav tias yuav pib los ntawm Q3 2011 uas Alcatel-Lucent thiab Ericsson yuav yog cov khoom siv rau 4G network.
LTE thev naus laus zis yog txuam nrog MIMO thiab OFDMA thev naus laus zis ua ke kom ua tiav cov ntaub ntawv siab dua raws li tau teev tseg los ntawm ITU rau 4G tes hauj lwm. Cov bandwidth yuav siv tau los ntawm 1.25MHz mus rau 20MHz uas yog ntau ntawm 1.25MHz.
Tus kwv yees cov ntaub ntawv siab tshaj plaws rau 4G network yog nyob ib puag ncig 100Mbps downlink thiab 50Mbps uplink nrog latency tsawg dua 50ms. AT&T Networks yuav txo qis qhov nrawm kom ntseeg tau tias txhua tus neeg siv khoom tuaj yeem siv LTE kom zoo. Tab sis qhov tseeb ceev yuav tsum sib txawv ntawm 6Mbps rau 8Mbps nrog rau qhov tshwj xeeb ntawm ib ncig ntawm 20Mbps (Peak Rate) thiab cov nuj nqis no yuav raug hloov pauv nrog kev nce qib hauv network. AT&T yuav cia siab tias yuav siv 10MHz=70 Mbps tus neeg nqa khoom xa tawm hauv lawv cov LTE tes hauj lwm.
Qhov txawv ntawm AT&T 3G thiab 4G networks
1. 3G tes hauj lwm siv thev naus laus zis xws li HSPA thiab AT&T 4G tes hauj lwm yuav siv thev naus laus zis HSPA+ thiab LTE ua ke hauv xov tooj cua interface.
2. 4G tes hauj lwm muaj qis dua latency uas qis dua 50ms thaum nyob hauv 3G tes hauj lwm nws qis dua 70ms.
3. Tus nqi nruab nrab cov ntaub ntawv rau AT&T 3G tes hauj lwm yog 1410 kbps downlink thiab 773 kbps nyob rau hauv uplink whilst AT&T 4G cog lus qhov nruab nrab 6-8 Mbps downlink speeds.
4. AT&T 3G network channel bandwidth yog 5MHz thiab hauv 4G nws yuav tsum siv qhov sib txawv bandwidth pib ntawm 1.25MHz txog 20MHz.
