KHOA CNG NGH THNG TIN i Hc Bch Khoa Nng ti:

Gio Vin Hng Dn

Mai Vn H

Sinh vin thc hin:

Nguyn Nh Ngha-09t3-8B Trnh Trung Kin-09t3-8B

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NI DUNG S TRNH BYKhi nim DSL(Digital Subscriber Line) ng dng v u im ca DSL Cc h thng xDSL pht trin theo nhiu hng Phn loi xDSL, u im & nhc im xDSL

M ng dyChuyn i giao thc s dng trong xDSL

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Khi nim DSL (Digital Subscriber Line):Khi nim DSL thng c vit xDSL l mt h hay mt nhm cng ngh v tiu chun DSL dng truyn d liu vi tc cao trn cp xon i x c th l vit tt ca: H, SH, I, V,A hay RA tu thuc vo loi dch v s dng DSL l cng ngh chuyn ti thng tin.

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u im

Nhc im

C bng thng rng. Tc truyn d.liu cao tn dng c mng in thoi c sn, v rng khp. Ph lp t v bo tr thp Cho php truyn tn hiu s v tng t trn cng 1 i cp xon vi tc cao truyn ti c nhiu ng dng khc nhau truy nhp internet, o to t xa, truyn d liu, chi game trc tuyn, hi ngh truyn hnh,..

DSl yu cu cht lng cp rt cao V bng tn rng => khi c 1 nhiu nh cng nh hng n thng tin B nhiu xuyn m, phn x tn hiu. Ph thuc vo khong cch4

Cc h thng pht trin theo nhiu hng

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Phn loi DSLHDSL:

Mi i cp truyn mt na d liu v truyn theo kiu song cng c trit ting di trn ng truyn.

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Khong cch truyn (0.5mm)Truyn tc cao S dng 2 hoc 3 i cp truyn dl

3 n 5 km ty loi modermKhng cn dng repeater Tc ln n 2Mbps

Hiu mt cch n gin nht, ADSL l s thay th vi tc cao cho thit b Modem hoc ISDN gip truy nhp Internet vi tc cao v nhanh hn. Cho php h thng tng tc truyn d liu t nh cung cp n khch hng ln n 6Mbps, 8Mbps. H thng ADSL c pht trin thnh RADSL v G.Lite l loi ADSL c tc thp hn.

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IDSL ( ISDN Digital Subscriber Line):Khi nim

IDSL c pht trin t Basic Rate ISDN v cn c gi l ISDN DSL v tc truyn d liu ca n cng gn ging vi tc truyn d liu ca ISDN. N cng s dng m ng truyn ISDN l 2B1Q. Tuy nhin, dng d liu v ng dng ca IDSL th khc vi ISDN.

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Khc nhau gia IDSL v ISDN Khng s dng quay s ( dial-up) trong IDSL (cn ISDN th dng quay s) - IDSL khng s dng chuyn mch nh ISDN - IDSL ch dng mt mch in cn ISDN dng hai mch in - IDSL khng qua h thng tng i thai CO m ch kt ni vo thit b Router tng ng ti CO, cn ISDN th phi qua h thng chuyn mch in thai.c im Tc h tr IDSL: 64, 128, 144 kbps (symmetric) S i dy cp ng s dng: 1 Khang cch truyn: 8 Km (0.5mm, 24AWG)

ASDL.Lite ( G.Lite) (Splitterless ADSL)G.Lite cng ging nh ADSL nhng khng dng splitter ti pha khch hnh. G.Lite dng k thut iu ch DMT v c tc downstream 1.5 Mbps, upstream 384 kbps G.Lite cng dng chung ng dy in thai ca POTS truy cp internet nhng khng dng splitter ti pha khch hng (CPE) m ch dng splitter ti CO.

c im Tc : Download 1.5 Mbps, Upload 384 kbps S i cp ng s dng: 01 Khang cch truyn (0.5mm): 03 . . 08 Km ty thuc tc

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VDSL ( Very high-Speed Digital Subscriber Line)VDSL h tr c hai modes i xng v khng i xng. VDSL cho tc downstream n 52Mbps vi khang cch 0.3Km v tc 13Mbps cho 1.0Km.Trong modes i xng VDSL t tc 26Mbps vi khang cch 0.3Km v tc 13Mbps cho1.0Km

VDSL rt thch hp cho cc ng dng bng rng trong tng lai. ng dng chnh ca VDSL l ng dng Video on Demand (VoD) hay cc ng dng Multimedia Tc : n 52Mbps trong modes khng i xng, n 26Mbps trong moderm i xng S i cp ng s dng: 01 i Khong cch truyn vi tc ti a (0.5mm): 300m12

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M ng dyM ng dy l mt dng thng tin truyn trn ng dy. M ng dy trong h thng xDSL l kiu iu ch ban u. Trong h thng xDSL s dng cc kiu iu ch sau:2B1Q: 2 Binary,1 Quaternary - QAM: Quadrature Amplitude Modulation - CAP: Carrierless Amplitude and Phase - DMT: Discrete Multitone Transmission14

Cc kiu iu ch

2B1Q: K thut 2B1Q l s m ha bin bn mc dng bi ISDN, IDSL v HDSL. K thut ny cho s dng bng thng hiu qu gp hai ln nhng hai mc bin ca n th ch bng vi mt m nh phn thng.

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Cc kiu iu ch

QAM: l kiu iu ch hiu qu, n kt hp hai kiu iu ch bin v pha phn phi s lng ln bits/Hz ca bng thng. Trong QAM mt knh tn hiu s dng pha v knh khc dng bin . QAM c dng trong modems VDSL bi v s dng cng sut thp v ch phc tp hn cc kiu u ch khc.

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Cc kiu iu ch

CAP: iu ch CAP th ging vi QAM. y c s khc nhau l pha ca tn hiu sng mang s c dch chuyn lin tc. CAP cho php gim nhiu xuyn knh (crosstalk) v qu trnh iu ch c n gin hn. CAP c dng trong modems ADSL.

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Cc kiu iu ch

DMT: S dng vic truyn phn chia thnh nhiu knh nh thay v s dng mt knh. DMT chia mt lung tn hiu truyn tc cao thnh nhiu lung tn hiu tc thp hn v cc lung ny c iu ch thnh nhiu knh nh. Khi nhn th cc knh nh c tc thp c kt hp li thnh lung d liu c tc cao. DMT c s dng ch yu trong modems ADSL18

o c tnh ca ng dy: u tin ta truyn mt tone o c tnh ca ng dy. Qu trnh ny c thc hin ti ATU-R, nhng thng tin phn phi bit s c chuyn n ATU-C thng qua ng cp ng tc thp. Sa Li v Phn Tch Li19

Vic thng tin truyn trn i cp ng lun lun b nhiu t nhiu ngun khc nhau. Nhiu c th l tn hiu gy nhiu tc thi nh tn hiu cao th tc ng ln i cp ng, nhiu cng c th l lin tc nh nhiu xuyn knh (crosstalk).

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c im

Khi nhiu xy ra, n gy ra mt tn hiu hay d liu nhn b li. gip hn ch nhiu th phi dng b phn tch li v nhng bits sa li c thm vo trong lung d liu khi truyn i. C hai kiu phn tch li v bo v truyn lung d liu dng trong DSL: - M kha (Block coding) - M xon hay m chp (Convolutional coding or continuous coding)

Giao thc l mt ngn ng, cch thc dng ci t, bo dng v ngt knh thng tin. Vi nhng h thng khc nhau th dng nhng kiu giao thc khc nhau. Khi nhng h thng khc nhau kt ni nhau th giao thc phi c chuyn i v cho php s dng c nhng dng ngn ng khc nhau, thi gian s dng, nhng tham s m ha khc

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