Ofcourse,intheactualdownloadprocess,thequalityoflines,equipment(includingcomputersandotherequipment),etc.willalsohaveamoreorlessimpactonthespeed.
Currently,theADSLweuseisanasymmetrictransmissionmethod,thatis,theupstreamrateisnotequaltothedownstreamrate;theupstreamrateofADSLis640Kbpsto1Mbps,thedownstreamrateis1Mbpsto8Mbps,andthegeneralis2Mbps.Notethatthedownlinkrateisnotequaltothedownloadrate.Usuallywhenwedownloadsoftwareormovies,wecanonlyreach220KBpsinsteadof2Mbps.Infact,thebroadbandof2Mis2Mbits(Bit)insteadof2Mbytes(Byte).Accordingtotheformulaof8bits(Bit)=1byte(Byte),letuscalculate:2MBit=2048KBit=256KByte,sotheoreticallythemaximumdownloadspeedof2Mbroadbandshouldbe256K,andbecauseofsomeotherfactors,theactualdownloadspeedAround200Kisnormal.
Forexample,ChinaalsosuccessfullydevelopedChina3Gin2008.Thetheoreticalpeakdownlinkspeedcanreach3.6Mbit/s,andthepeakuplinkspeedcanreach384kbit/s.TheLTEtechnologyunderdevelopmenthasatheoreticalpeakdownlinkspeedof150Mbit/sandapeakuplinkspeedof50Mbit/s;whileforLTE-Advancedtechnology,thetheoreticalpeakdownlinkspeedcanreach1Gbit/sandthepeakuplinkspeedcanalsoreach500Mbit./s.