71037393-wcdmanangcapgsmlen3g

7/30/2019 71037393-WCDMAnangcapGSMlen3G

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X

L

THNG

TIN

V

TRUYN

THNG

2006-

O

QUANG

ANH

b gio dc vo to trng i hc bchkhoa hni

---------------------------------------

lun vn thc s khoa hc

ngnh : XL THNG TIN V TRUYN THNG

NGHIN CU CNG NGH WCDMA NGDNGCHO NNG CPMNG GSM CA

VIETTEL LN 3G

O QUANG ANH

H Ni2008 H Ni 2008


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BN CAM OAN

Ti l o Quang Anh, hc vin cao hc lp XLTT&TT kha 2006 - 2008.

Thy gio hng dn l TS. Bch Thnh L.

Ti xin cam oan ton bni dung c trnh by trong bn lun vn nay l

kt qu tm hiu v nghin cu ca ring ti, trong qu trnh nghin cu ti

Nghin cu cng ngh CDMA ng dng cho nng cp mng GSM ca Viettel

ln 3G. Cc kt qu v d liu c nu trong lun vn l hon ton trung

thc v r rng. Mi thng tin trch dn u c tun theo lut shu tr tu,

lit k r rng cc ti liu tham kho. Ti xin chu hon ton trch nhim vi

nhng ni dung c vit trong lun vn ny.

H ni, ngy 06 thng 11 nm 2008.

HC VIN

O QUANG ANH


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MCLC

TRANG 1 .. 1LI CAM OAN ......2MC LC ..3DANH MC CC TVIT TT ...............................................................................4MU .........................................................................................................................6CHNG 1 GII THIU CHUNG ............................................................................8

1.1 Mc tiu v nhim vca ti.............................................................................81.2 Tnh hnh pht trin cng ngh 3G trn thgii v ti Vit Nam..........................81.3 So snh h thng WCDMA vi cc h thng 2G ...............................................191.4. So snh, nh gi 2 cng ngh W-CDMA v CDMA - 2000 .............................22

CHNG 2 H THNG WCDMA ..........................................................................252.1. H thng thng tin tri ph..................................................................................252.2. Giithiu chung hthngUMTS .......................................................................272.3. Mng truy nhp UTRAN.....................................................................................292.4. Mng li CN ........................................................................................................332.5. Thit b ngis dng UE (user Equipment) .....................................................342.6. Mng truyndn..................................................................................................35

CHNG 3 CC IU KIN V K THUT, CNG NGH CHO QUTRNH CHUYNI LN 3G ................................................................................37

3.1. Kh nng chuyn i 2G ln 3G .........................................................................37

3.2. Cu trc h thng GSM ang tnti ...................................................................403.3. Giai on HSCSD................................................................................................443.4. Giai on GPRS ..................................................................................................463.5. Giai onEDGE..................................................................................................493.6. Giai on UMTS .................................................................................................52

CHNG 4 CC PHNG N CNG NGH V GII PHP PHT TRINMNG 3G CHO VIETTEL ........................................................................................54

4.1 Gii thiuv cng ty Viettel Telecom .................................................................544.2. nh gi v cs htng mng hinc .............................................................544.3 Phn tch cc phng n v la chngiiphp ...................................................634.4. Tnh ton cc thng s v xy dng cu trc mng............................................734.5. Mt sthitb mng 3G ca Siemens.................................................................90

KT LUN V KIN NGH TRIN KHAI ..........................................................100TI LIU THAM KHO .........................................................................................102


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4

DANH MC CC TVIT TT

3G Third GenerationTh h th ba

3GPP Third Generation Partnership ProjectD n i tc 3G

ATM Asynchronous Transfer ModeCh truyn khng ng b

BSC Base Station ControllerBiu khin trm gc

BSS Base Station SubsystemPhn h trmgc

BTS Base Transceiver StationTrm thu pht gc

CDMA Code Division Multiple Accessa truy nhp theo phn mEDGE Enhanced Data Rates for GSM EvolutionTc d liu cao

FDD Frequency Division DuplexSong cng phn tn

GGSN Gateway GPRS Support NodeNt h trcng GPRS

GPRS General Packet Radio ServiceDch v v tuyn gi chung

GSM Global System for Mobile CommunicationsH thng GSM

HLR Home Location RegisterBng k v tr thng tr

HSCSD High Speed Circuit Switched DataD liu chuyn mch knh

tc cao

IP Internet ProtocolGiao thc Internet

ITU International Telecommunications UnionLin minh vin thngquc t

IPv6 IP version 6IP phin bn 6

IWF Internetworking FunctionsKhi chc nng lin mngMAP Mobile Application ProtocolGiao thc ng dng di ng

MS Mobile StaionMy di ng

MSC Mobile Switching CenterTrung tm chuyn mch di ng


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PLMN Public Land Mobile NetworkMng di ng mtt cng cng

PSTN Public Switched Telephone NetworkMng in thoi chuyn

mch gi cng cngRAN Radio Access NetworkMng truy nhp v tuyn

SGSN Serving GPRS Support NodeNt h trphc v GPRS

SMS Short Message ServiceDch v nhn tin ngn

TCP Trasmission Control ProtocolGiao thc iu khin truyn

TDD Time Division DuplexSong cng phn thi

TDMA Time Division Multiple Access a truy nhp phn chia theothi gian

UMTS Universal Mobile Telecommunications SystemH thng thngtin di ng UMTS

UTRA Universal Terrestrial Radio AccessTruy nhp v tuyn mttca UMTS

VLR Visitor Location RegisterBng k v tr tm tr

VPN Virtual Private NetworkMng ring o

WAP Wireless Application Protocol Giao thc ng dng v tuyn

WCDMA Wideband Code Division Multiple Accessa truy nhp phnm bng rng


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6

MU

Nhu cu trao i thng tin l nhu cu thit yu trong x hi hin i. S ra

i ca thng tin di ng l mt bc ngot lch s trong ngnh vin thng cng

nh bc pht trin quan trng ca loi ngi. Qua qu trnh pht trin v cho

n ngy nay l mng di ng 3G. Cng vi vic cho php kt ni mi ni,

mi lc, l mt trong nhng kh nng ca mng 3G. 3G mang ti nhiu tin ch,

ng dng hn l kh nng di ng cho Internet. Cc dch v mi s xut hin

nh nhn tin a phng tin, cc dch vnh v, cc dch v thng tin c nhn,vui chi gii tr, cc dch v ngn hng, thanh ton in t... s pht trin mnh.

Vit Nam, cc h thng thng tin di ng th h th ba cng v sc

nhanh chng trin khai.

theo kp xu th chung ca th gii l tin ti mng th h sau 3G v

cung cp cc dch v mi, vic nghin cu trin khai, chuyni sang mng

3G ti Vit Nam l cn thit. i vi cc nh khai thc mng di ng GSM thci ch 3G l cc h thng thng tin di ng CDMA bng rng (W-CDMA)

theo chun IMT-2000. Xut pht tnh hng ny, lun vn cpn (Nghin

cu cng ngh CDMA ng dng cho nng cp mng GSM ca Viettel ln 3G) nghin

cu tng quan v cng ngh W-CDMA v h thng thng tin di ng W-CDMA

ni chung, phn tch cc qu trnh pht trin ln 3G t ng dng la chn,

tnh ton dng lng mng trn cs xy dng cu trc 3G, ph hp vi xu

hng pht trin mng thng tin di ng Viettel.

Lun vn c chia lm 4 chng:

Chng 1: Gii thiu chung v tnh hnh pht trin di ng 3G tn th gii

v ti Vit nam.


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Chng 2: H thng WCDMA: Gii thiu tng quan v cng ngh v h

thng WCDMA

Chng 3: Phn tch qu trnh pht trin ln mng 3G.Chng 4: ng dng mng 3G cho pht trin mng Viettel.

Mc d ht sc c gng v nhnc nhiu kin ng gp qu bu

t cc thy c gio, nhng do thi gian c hn, lun vn cha th i su vo

nhiu kha cnh k thut khc. Song nhng vn m lun vn cp ti l

nhng yu t quan trng v ang a vo sdng cng nh nhng ng dng

ca n trong pht trin mng thng tin di ng 3G. Rt mong c sng gpv gip hn na ca cc thy c gio v ng nghip lun vn c kt

qu tt hn.

Sau cng em xin chn thnh cm n thy gio TS Bch Thnh L, ngi

trc tip hng dn v gip em hon thnh lun vn ny. Em xin cm n cc

thy c gio trong khoa Cng ngh Thng tin gip em trong sut qu trnh

hc tp cng nh trong qu trnh hon thnh lun vn ny.

Tc gi

o Quang Anh


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CHNG 1

GII THIU CHUNG

1.1 Mc tiu v nhim vcati

1.1.1 Mc tiu cati

Nghin cu cng ngh WCDMA v qu trnh nng cp mng GSM(2G)

ln WCDMA(3G) ng dng cho pht trin mng thng tin di ng Viettel.

1.1.2 Nhim vcati

nh gi tnh hnh pht trin cng ngh mng 3G trn th gii cng nh

ti Vit Nam v nu ln s cn thit pht trin 3G ti Vit Nam.

Tng quan cng ngh WCDMA v mng UMTS phn tch cc qu trnh

pht trin nng cp mng GSM (2G) ln mng WCDMA (3G).

a ra cc phng n c th thc hin pht trin mng GSM ln 3G cho

Viettel, la chn v xut phng n ti u, m bo khi pht trin mng l

tt nht c v mt k thut v v mt kinh t cho vicu t l c hiu qu nht.

Tnh ton s b cc thng s k thut mng v tuyn da trn kh nng tng

trng thu bao 3G. Trn cs la chn gii php cng ngh v xy dng

cu trc mng cho c phn truy nhp v tuyn v phn mng li.1.2 Tnh hnh pht trincng ngh 3G trn th gii v ti VitNam

1.2.1 Lch s v xu hng pht trin


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Hnh 1.1. Cc bc pht trinn mng th h th 3

Lch s ra i v s pht trin ca dch v di ng t th hu tin 1G ti th

h 3G tri qua nhiu giai on khc nhau. Bng 1.1 cho thy tm lc qu trnhtin trin ca cng ngh thng tin di ng.

Bng 1.1 tm lc qu trnh tin trin ca cng ngh thng tin di ng

Qu trnh bt u vi cc thit ku tin c bitn nh l 1G trong

nhng nm 70 ca th k trc. Cc h thng ra i sm nhtc thc hin

da trn cng ngh tng t v cu trc t bo cbn ca thng tin di ng.

Nhiu vn c tnh nguyn tccbn c gii quyt trong nhng h thng

ny. V c nhiu cc h thng khng tng thch c a ra cung cp dch

v trong nhng nm 80, nh: AMPS, TACS, NMT,

Cc h thng th h th 2 (2G) c xy dng trong nhng nm 80 vn

c sdng ch yu cho thoi nhng c thc hin trn cscng ngh

s, bao gm cc k thut x l tn hiu s. Cc h thng 2G ny cung cp cc


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dch v thng tin d liu chuyn mch knh tc thp. Tnh cnh tranh li

mt ln na dn ti vic thit k v thc hin cc h thng b phn ho thnh cc

chun khc nhau khng tng thch nh: GSM (h thng di ng ton cu) chyuchu u, TDMA (a truy nhp phn chia theo thi gian) IS-54/IS-136

M, PDC (h thng di ng t bo s c nhn) Nht v CDMA (a truy nhp

phn chia theo m) IS-95, mt h thng khc ti M. Cc h thng ny hot

ng rng khp trn lnh th quc ra hoc quc t v hin nay chng vn chim

vai tr l cc h thng cho, mc d tc d liu ca cc thu bao trong h

thng b gii hn nhiu.Bc chuyn tip gia 2G v 3G l 2.5G. Th h 2,5G c pht trin t

2G vi dch v d liu v cc phng thc chuyn mch gi, v n cng ch

trng ti cc dch v 3G cho cc mng 2G. Vcbn n l s pht trin ca

cng ngh 2G tng dung lng trn cc knh tn s v tuyn ca 2G v bc

u a cc dch v d liu dung lng cao hn vo, c th nng ti 384 Kbps.

Mt kha cnh rt quan trng ca 2.5G l cc knh d liuc ti u ho cho

d liu gi truy nhp vo Internet t cc thit b di ng nh in thoi, PDA

hoc my tnh xch tay. Trn cng mt mng li vi 2G, th h 2.5G a

internet vo th gii thng tin di ng c nhn. y thc s l mt khi nim

mang tnh cch mng cho h thng vin thng lai ghp hybrid.

Trong thp k 90, cc nh nghin cu nh ngha ra h thng di ng

th h k tip, th h th 3, loi trc nhng s khng tng thch ca cc

h thng trc y v thc s trthnh h thng ton cu. H thng 3G c ccknh thoi cht lng cao cng nh cc kh nng v d liu bng rng, c th

t ti 2Mbps.


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Cc h thng 3G ha hn cung cp nhng dch v vin thng tc cao

hn, bao gm thoi, fax v internet bt c thi gian no, bt cni u vi s

chuyn vng roaming ton cu khng gin on. Chun 3G ton cu ca ITU m ng cho cc ng dng v dch v sng to (v d loi hnh gii tr a

phng tin, cc dch v da trn v tr,). Mng 3G u tin c thit lp ti

Nht bn nm 2001. Cc mng 2.5G, nh l GPRS (dch v v tuyn gi chung)

sn sng Chu u. Cng ngh 3G h trbng thng 144 Kbps vi tc di

chuyn ln (trn xe hi), 384 Kbps (trong mt khu vc), v 2 Mb ps (i vi

trng hp trong nh). Hnh 1.2 th hin cc dch vc tch hpmang thhth 3.Entertainme Financial Services

Telecommunication BroadcastingGame

Internet

Music

VOD

TVCable TV

Satellite TV

IP-TV Interactive TV

MMoobbiillee sseerrvviiccee

Hnh 1.2. Cc dch vc tch hp mng th h th 3

Cc dch vd liu (data) ca WCDMA

WCDMA cung cp cc dch v d liu tt cao hn v s dng hiu qu ph

bng tn hn cc cng ngh trc nh GSM, GPRS hoc EDGE. Phin bn

u tin ca WCDMA l R99 v phin bn mi nht gn y l HSDPA

(Release 5), HSUPA (Release 6) cung cp tt d liu tc cao cho ng


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ln UL v ng xung ring bit DL. Phin bn trong tng lai s l HSPA

(Release 7) v LTE (Release 8), nh trong hnh 1.3

Hnh 1.3 Cc dch v d liu (data) ca WCDMA

1.2.2 Tnh hnh pht trin 3G trn th giiCho n thng 1/2008, c 197 nh khai thc kinh doanh thng tin di ng

th h th ba (3G) hotng trn th gii c 87 nc v vng lnh th, phc

v cho 180 triu thu bao. Sau y l s cc nc s dng dch v 3G.


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Hnh 1.4. Cc nc trin khai dch v 3G

Dch v 3G NhtBn v Hn Quc pht trin rt cao. Nhc s thc

y ca chnh ph v thi tch cc ca cc nh khai thc, ng dng cng ngh

3G hai nc ny t nm 2001; vic kch thch th trng thi gian u kh tt,

ngi dng cng tha thit vi dch v mi. Cc nc ng Nam cng pht

trin mnh m trong nhng nm gny, c bit l Singapore v Thi Lan.

Mc pht trin chung th trng thng tin di ng cc nc Chu u

rt cao, mc phcpdch v di ng ln n khong 90%, nhng cc nh khai


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thc truyn thng trin khai dch v 3G tng i thn trng, nc u tin trin

khai Chu u l B l vo 2002.

S pht trindch v 3G Chu M tng i chm chp so vi cc vngkhc trn th gii. n nm 2005 M mi bt u trin khai 3G.

Mc pht trindch v 3G ca Nht Bn v Hn Quc, hai nc Chu

, l chim hng u ca th gii; biu hin th trng 3G Chu u ni chung

l bnh bnh, nhng cng c im sng, ch yu l Italia v Anh; Chu M

th s pht trin M l tng i ni bt; cn Chu Phi l th trng sc

khai ph trong tng lai.Cng vi ra i dch v 3G ca cc nh khai thc, cc nh cung cp thit

b u cui nhanh chng a ra a dng chng loi. Hin nay my u cui

WCDMA c 26 nhn hiu, 186 loi sn phm; sn phm u cui EV-DO

cng ln n 156 loi.

Trong cc loi dch v ca 3G, ng gp ln nht vo thu nhp vn l dch

vin thoi, chim hn 90% tng thu nhp, nhng ng gp vo thu nhp ca

cc dch v phi thoiang tng trng u. Dch v 3G c nh gi cao nht

trong tng lai bao gm a truyn thng, truyn hnh thu qua my cm tay.v.v

Doanh thu t cc dch v ni dung v video chim t trng ln trong mng

3G, v doanh thu trn mt u thu bao ARPU cao hn 2G 40%. Hnh 1.5 th

hin kt cu doanh thu cc dch v 3G.


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3G Worldwide Revenues Composition 2008

Businiess MMS,7%

Mobile InternetAccess, 3%

Location-BasedServices, 2%

Simple Voice, 28%

Customisedinfotainment, 36%

MobileIntranet/Extranet,

14%

Rich Voice, 4%

Consumer MMS,6%

Hnh 1.5 Kt cu doanh thu cc dch v 3G

Do hon cnh th trng cc nc c khc nhau, sch lc pht trin 3G

m cc nh khai thc la chn cng khng hon ton ging nhau. Nht Bn

cc nh khai thc, nh DoCoMo, ch yu l thng qua s tin b ca k thut v

sng to mi v dch v i n thnh cng. Hin nay mng 3G Nht ph

sng n 99,7%. 94% thu bao dng 2G ang qu sang 3G, t l ny l cao

nht trn ton th gii. Cc nh khai thc v cc nh sn xut my cm tay phi

hp vi nhau thit k ch to my u cui. Gi c ca my cm tay 3G

tng ng vi my cm tay 2G, cho nn cc thu bao dng mun i my

cm tay. Cc nh khai thc a ra cc dch v mi rt hp dn trn mng, v d

nh trch xut m nhc, mua hng qua my cm tay v.v

Cng ty 3G ca Hutchison c tr schnh ng ti Hongkong cng l mt

trong s cc nh khai thc i u v dch v 3G trn ton cu; nm 10 giy php

3G cc th trng c, o, an Mch, Hongkong, Italia, Ai Len, Israel, Na Uy,

Anh, Thy in v.v n 175 triu dn, ch chi cho giy php tng cng n 10,2


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t USD. u t xy dng mng li 3G ca cng ty vt 27 t USD. Sch

lc pht trin 3G ca Cng ty 3G Hutchison l cc ph linh hot. S thu bao

dng 3G ca cng ty ny cha n 6 triu, nm nay s t ph 10 triu.S pht trin dch v 3G ca i a s cc nh khai thc Chu u l

tng i chm chp. Nguyn nhn ch yu, mt l chi tr cho giy php qu

cao, lm cho cc nh khai thc thiu lc pht trin; hai l nhu cu th trng

i vi 3G cha nhiu, ch khong 6% thu bao dng di ng c nhu cu 3G;

thng thng t l ny phitn 33%, nh khai thc mi c th thc hin cn

bng thu - chi.1.2.3 Xu hng pht trin 3G ti Vit Nam

Cc ng dng truyn thng hu ch nhin thoi truyn hnh, nh v v

tm kim thng tin, truy cp Internet, truyn ti d liu dung lng ln, nghe

nhc v xem video cht lng cao... cng nhiu ng dng dch v vin thng

tin tin khc c th thc hin c trn mng di ng 3G. Nhng Vit Nam

3G mi chang bc chp chng.

Th gii ang c 2 h thng 3G c chun ha song song tn ti, mt

da trn cng ngh CDMA cn gi l CDMA-2000, chun cn li do d n 3rd

Generation Partnership Project (3GPP) thc hin. 3GPP ang xem xt tiu chun

UTRA - UMTS Terrestrial Radio Access TS. Tiu chun ny c 2 s truy

nhp v tuyn. Mt trong s c gi l CDMA bng thng rng (WCDMA).

Cn c vo nhng thng tin ni trn th Vit Nam gia nhp vo nhm cc

nc trin khai dch vin thoi th h th 3 (3G), chnh l dch vinthoi di ng CDMA ca nh khai thc mng S-Fone.

Tuy nhin, cng ngh CDMA-2000 1X m S-Fone trin khai cng ch

c coi l giai on khi u ca mt h thng 3G hon chnh, v CDMA-2000


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c n ba phin bn: CDMA-2000 1X, CDMA-2000 1xEV-DO v CDMA-2000

1xEV-DV. CDMA2000 1X dnh cho thoi v d liu, hot ng trn knh

CDMA 1,25MHz chun, cho php truyn d liu t 307Kbps. CDMA20001xEV-DO l phin bn cao hn, ti u cho nhng dch v d liu dung lng

ln v tc cao da trn cng ngh CDMA High Data Rate (tc ti a vt

2Mbps).

CDMA2000 1xEV-DO t tc truyn d liu vt 10Mbps. Ngha l

trin khai lot cc ng dng c dung lng ln, c coi l th mnh ca 3G

ngy nay th CDMA 2000 1X ca S-Fone cha tm. Trong khi , vn hin nhiu ngi quan tm l bao gingi s dng cng ngh GSM (chim

95% s ngi dng in thoi di ng ti Vit Nam) c th s dng 3G.

Nh sn xutchy trc, mt ln na cc nh sn xut li i trc cc

nh khai thc dch vin thoi di ng, khi ln lt Nokia, Sony Eircsson

bn ra th trng Vit Nam vi model in thoi di ng h trcng ngh 3G

nh Nokia 6680, 6630; Sony Ericsson Z800i, K608i... Trong khi lot sn

phm 3G Nseries d cha c Nokia bn chnh thc ti Vit Nam cng ang

thu ht c s ch ca ngi tiu dng, nht l nhng ngi a thch cng

ngh.

Vcbn, y ch l s chng minh ca cc hng cho th trng thy h

c nhng sn phm cao cp v tch hp cc cng nghn u, ch cc nh

sn xut cng tha hiu gi tr s dng cng ngh 3G ti Vit Nam cha c v

cc nh khai thc mng cha trin khai ng dng 3G. Tt nhin, trn th gii

khng ch c Sony Ericsson hay Nokia m cn c Samsung, Motorola, LG...

thm ch l c Huewei (Trung Quc) cng gp mt vo nhm cc nh sn xut

in thoi di ng 3G vi sn phm U626.


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Khng ch c cc hng sn xutin thoi di ng m ngay c Qualcomm,

nh pht trin v pht minh hng u ca cng ngh CDMA cng c nhiu k

hoch khuch trng 3G ti Vit Nam. Cui thng 7/2005, Qualcomm loan bos mTrung Tm Nghin Cu Cng Ngh 3G u tin ti Vit Nam. Thi gian

u, trung tm s t chc cc kha o to v pht trin 3G, gii thiu cng ngh

CDMA, WCDMA v cch lp trnh trn mi trng BREW (Binary Runtime

Environment of Wireless) ca Qualcomm.

Cc kha hc c thit k cho ngi c kinh nghim lp trnh bng

ngn ng C v C++ thc y vicng dng rng ri cng ngh 3G ti VitNam v cc nc trong khu vc. y cng l mt phn ca d n thc y s

dng 3G ti Chu m Qualcomm gii thiu vo nm ngoi. Cha ht, gia

thng 9 va qua, ti H Ni, Qualcomm t chc tho v o to v BREW,

gii thiu gii php tng th v d liu v ng dng trn thit b di ng ca

Qualcomm. BREW cng chnh l mt trong nhng ng lc thc y s pht

trin cc ng dng v ni dung ca hu ht cc hotng 3G trn ton th gii.

Khi u l vic Viettel phi hp cng Ericsson thc hin thnh cng vic

trnh din cc dch v thng tin di ng 3G vo u nm 2006. Nhiung dng

thng tin di ng 3G th v nh in thoi truyn hnh, nh v ton cu v tm

kim thng tin, truy cp Internet, video cht lng cao... c thc hin trong

mi trng mng di ng tc cao.

Theo cc chuyn gia trong ngnh vin thng, ng ti 3G ca GSM l

WCDMA. Nhng trn con ng , cc nh khai thc dch v in thoi ding phi tri qua giai on 2,5 (2,5G). Th h 2,5G bao gm nhng g? l:

d liu chuyn mch gi tc cao (HSCSD), dch v v tuyn gi chung


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(GPRS - Viettel trin khai hn 3 nm nay), v Enhanced Data Rates for Global

Evolution (EDGE).

Nghe th n gin nhng thc t, trin khai 3G, mt trong nhng khkhn ca cc nh khai thc mng GSM l vn ng dng. Ngoi ra, h cng

ang phi tm cu tr li cho cu hi: u t h tng c p ng c nhu cu

ca ngi dng hay khng? Bi trin khai 3G trn mng in thoi hin hnh s

theo hng nng cp t nn tng c s c. Song song vi th nghim cn

phi xy dng d n u t, phi c thi gian hon tt th tc d n... Mt

yu t na l khch hng phi c my u cui thch hp khi s dng cng ngh3G trong dch v thng tin di ng.

Bn pha CDMA, ngoi S-Fone nh ni trn, ns ln ca ngnh

in thoi di ng l Hanoi Telecom cng nhiu ln nhc ti vic h s s

dng ngay cng ngh CDMA2000 1xEV-DO khi bt u chnh thc thng mi

ho cc dch v di ng. Hn nhin ai cng bit CDMA2000 1xEV-DO ang gt

hi nhiu thnh cng trong vic trin khai cc dch v lin quan n d liu ti

cc nc ang s dng cng ngh ny m Hn Quc l mt v din hnh.

D ci ch 3G c th cn cch xa nhng hinc nh sn xut ln nh khai

thc dch vu c nhng bc i thch hp tin ti 3G, vn cn li l

bao gi? Mt trong nhng yu t quytnh iu ny l nhu cu v s lng

ngi dng.

1.3 So snh h thng WCDMA vi cc h thng 2G

1.3.1. So snh WCDMA v GSM

Bng 1.2. So snh hai h thng GSM v WCDMA

GSM WCDMA

Di tn 900 MHz v 1800 MHz. Di tn xp x 2 GHz.


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rng bng tn knh 200 KHz. rng bng tn knh 5 MHz.

GSM - 13,4 kbps + 8 kbps n 384 kbps i vi

trm di ng.+ Ln ti 2 Mbps vi trm c nh.

Phng php a truy cp TDMA. Phng php a truy cp CDMA.

Qui hoch v tuyn c tnh cht

tnh vi vic tng lulng.

Qui hoch v tuyn c tnhcht

Dung lng: dung lng tnh c cho

bi mt cu hnh phn cng no .

Dung lng ty thuc vo mc

nhiu, do vy rt nhy cm vi

cu hnh mng.

iu khin cng sut: cc thut ton

iu khin cng sut n gin.

iu khin cng sut l vn

thit yu trong mng.

Chuyn giao: Ch c chuyn giaocng.

Chuyn giao: c 3 loi chuyngiao:

1.3.2. So snh WCDMA v IS-95

C WCDMA v IS-95 u s dng cng ngh CDMA tri ph trc tip. Tc

chip 3,84 Mcps, h thng WCDMA cho php tc bit cao hn. Tc chip

cao hn cng gip kh nng phn tp a ng nhiu hn so vi tc chip

1,2288 Mcps, c bit nhng cell nh th.

Bng 1.3: So snh hai h thng WCDMA v IS - 95

Cc thng s WCDMA IS-95

rng bng tn 5 MHz 1,25 MHz

Tc chip 3,84 Mcps 1,2288 Mcps

Tn s iu khin

cng sut

1500 Hz, c ng lnln

ng xung

ng ln: 800 Hz,

ng xung: iu khin


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Chuyn giao gia cc

tn s

cng sut thp

C C th, nhng cha xc

nh r phng php oCc thut ton qun

l ngun ti nguyn v

tuyn

hiu qu

C, gip ci thin

c cht lng dch

v theo

yu cu

Khng cn thit ch

i vi cc mng thoi

S liu gi Lch trnh gi da theo ti S liu gi

c truyn nh i

vi cc cuc gi ngn

s dng

chuyn

mch knh

Phn tp truyn pht

ng xung

H tr ci thin

dung lng ng

xung

Tiu chun khng h tr

WCDMA c kh nng iu khin cng sut vng khp kn nhanh c

ng ln v ng xung, trong khi IS-95 sdng iu khin cng sut nhanh

chng ln. iu khin cng sut nhanh ng xung gip ci thin cht

lng ng truyn v tng cng dung lng ng xung. iu ny i hi

cc my u cui phi c cc tnh nng mi nh iu khin cng sut vng

ngoi... m cc my u cui ca IS-95 khng cn.

H thng IS-95 nhm mc ch chnh ng dng macro cell. Cc trm

gc macro cell c t trn mi nh, c th d dng nhn c tn hiu

GPS. Trm gc IS-95 cn phic ng b v qu trnh ng b thc hin nh

h thng GPS. S cn thit c tn hiu GPS lm kh nng trin khai cell trong

nh v micro cell kh khn hn, bi v vic nhn tn hiu GPS m khng c kt

ni trong tm nhn thng n cc v tinh GPS l kh khn. V vy, ngi ta thit

k h thng WCDMA vi cc trmgc khng ngb, ti khng cn tn hiu


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ng b tGPS. Cc trmgc khng ng b khin cho vic chuyn giao ca h

thng WCDMA hi khc so vi IS-95.

Chuyn giao gia cc tn s c xem l quan trng i vi h thngWCDMA ti a ha vic s dng mt s sng mang mi trm gc. h

thng IS-95, phng php o lng gia cc tn s cha c xc nh r, khin

cho vic chuyn giao gia cc tn s trnn kh khn hn.

1.4. So snh, nh gi 2 cng ngh W-CDMA v CDMA - 2000

1.4.1. im ging nhau

- u da trn cng ngh tri ph trc tip.- up ng y cc yu cu ca IMT-2000.

+ Duy tr h tr cc dch v truyn thng.

+ H tr cc dch va phng tin tc cao, d liu gi v truy nhp IP.

1.4.2. Nhng khc bitchnh

Cc khc bit chnh v k thut gia hai cng ngh WCDMA v 2000 c cho

trong bng sau:

Bng 1.4 So snh s khc nhau gia WCDMA v CDMA2000

Cc thng s WCDMA 2000

Phng thc truy

nhp v ghp knh

Khng c ch asng

mang

C ch a sng mang

Bng thng 5 MHz, 10MHz Nx1,25 MHz

(N=1,3,6,9,12) Tc chip 3,84 McpsNx1,2288 Mcps

(N=1,3,6,9,12)

iu ch QPSK (cho c hai hng) QPSK (BTS-MS),

BPSK (MS-BTS)

Cu trc khung tn 10 ms i vi lp vt l 5 msi vi bo hiu


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hiu 10, 20, 40, 80 ms i

vi lp truyn dn

M ha knh Dng m c h stri ph bin thin

trc giao

(OVSF), t 4 - 256 bit

20, 40, 80 i vi lp vt l

dng m Walsh, t 4 -128 bit

M nhn dng i

vi sector

Dng 512 m ngu

nhin ha, mi m

nhn dng mt sector

ring bit

dng chung mt m PN

ngn, nhng s dng 512

gi tr PN offset khc

nhau nhn dng cc

sector khc

nhau

M nhn dng MS Dng m ngu nhin

ha, gn bi sector

nhn dng MS

dng chung mt m PN

di, nhng to ra cc gi

tr PN offset khc nhau

theo s seri thit b

ca MS nhn

dng cc MS khcnhau

Vng b, W-CDMA dng d b ch FDD, cn ch TDD cc

trm gc c phn cpng b, nu khng cn roaming ton cu th khng cn

ng b t h thng nh v ton cu GPS (Global Positioning System). iu ny

phn no to cho h thng c tnh c lp hn. Trong khi cdma-2000 bt buc

cn GPS ngb.

V tnh tng thch ngc vi mng li 2G, W-CDMA c xy dng trn

cs bo hiu mng li GSM-MAP cn cdma-2000 trn csIS-41 (mng li

ca IS-95 CDMA). Nh vy, nhiu kh nng UTRA c chn bi cc nh khai


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thc GSM, trong khi nh khai thc CDMA IS-95 chn CDMA- 2000.


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1.4.3. c im bng tn

W-CDMA c ph trong phn bng tn ca IMT-2000. Tuy nhin Chu u

v Nht c h thng DECT v PHS chim mt phn nh ph tn. Phn phtn cn li c s dng cho W-CDMA vi bng thng chun l 5MHz.

cdma- 2000 M tn s cho 3G theo WRC-92 c phn chia ht cho

dch v PCS. Do cdma-2000 c thit k c th hot ng chung vi IS-

95 CDMA dng bng thng cs1,25MHz. cung cp dch v tc cao,

cdma2000 ghp 3 knh 1,25MHz (CDMA a sng mang) hoc cng c th tri

ph trc tip trn bng thng 3,75MHz (1,25MHz x 3).1.4.4. Nhng pht trintip

Tc chip ca UTRA ban u l 4,096Mcps c thng nht gim

xung 3,84Mcps gn vi tc chip ca cdma- 2000 l 3,6864Mcps cho php

d dng ch to my u cui c 2 ch hn.

Ngi ta cn tip tc chun ho W-CDMA v cdma-2000 pha tip theo

c th tng thch ngc vi c hai loi mng li GSM-MAP v IS-41. Nh vy

vic chn UTRA hay cdma-2000 ph thuc chnh vo mc tiu roaming ton cu

vi th trng ln hn v gii php lm cu trc u cui cng nh mng li n

gin hn.

Tm li, c th ni rng khng th khng nh cng ngh no u vit hn.

Bi th, tu thuc vo h tng sn c m vic dng cdma-2000 hay W-CDMA s

thun li hn cho vic pht trin. Mc d cc t chc chun ho vn tip tc c

gng t c kh nng u ni linh hot gia cc mng li khc nhau, W-

CDMA vn thun li hn i vi cc nh khai thc GSM hin c vi giao thc

mng li GSM-MAP. Ngc li, CDMA- 2000 thun tin cho vic nng cp t

h thng cdmaOne (CDMA IS-95) hin c vi giao thc mng li ANSI-41.


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CHNG 2

H THNGWCDMA

2.1. H thng thng tin tri ph

Nu c mt tn hiu vi rng bng tn l W, thi gian tn ti l T th

khng gian ph ca tn hiu ny xp x l 2WT. tri rng ph ca tn hiu ny

c 2 cch:

- Cch 1: Tng gi tr W bng tri ph trong min tn s (tri ph dy trc

tip v tri ph nhy tn ).

- Cch 2: Tng gi tr T bng tri ph trong min thi gian (tri ph nhythi gian).

Nh vy c ba kiu h thng tri phcbn: tri ph dy trc tip DSSS (Direct

Sequence Spreading Spectrum), tri ph nhy tn FHSS (Frequency Hopping

Spreading Spectrum) v tri ph nhy thi gian THSS (Time Hopping Spreading

Spectrum). Ngoi ra cng c th tng hp cc h thng trn thnh h thng lai

ghp.

H thng DSSS thc hin tri ph bng cch nhn tn hiu ngun vi mt tn

hiu gi ngu nhin c tc chip (RC = l/Tc, Tc l thi gian mt chip) cao hn

nhiu tc bit (Rb = l/Tb, Tb l thi gian mt bit) ca lung s cn pht.

Tb = TnBin Tb = Tn TC

t

Hnh 2.1 Tri ph dy trc tip


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K hiu:

Tn: Chu k ca m gi ngu nhin dng cho tri ph.

Tb: Thi gian mt bit ca lung s cn pht.Tc: Thi gian mt chip ca m tri ph.

H thng FHSS thc hin tri ph bng cch nhy tn s mang trn mt

tp ln cc tn s. Mu nhy tn c dng gi ngu nhin. Tn s mang trong

khong thi gian ca mt chip Tc gi nguyn khng i. Tc nhy tn c th

nhanh hoc chm. Trong h thng nhy tn nhanh, nhy tnc thc hintc

cao hn tc bit ca bn tin, cn h thng nhy tn chm th ngc li.

fn

f1

T 2T tHnh 2.2: Tri ph nhy tn(FHSS)

Trong h thng THSS, mt khi cc bit s liu c nn v c pht

ngt qung trong mt hay nhiu khe thi gian trong mt khung cha mt s

lng ln cc khe thi gian. Mt mu nhy thi gian s xc nh cc khe thi

gian no c sdng truyn dn trong mi khung. rng khe t = T1/M,


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trong M l s khe thi gian trong mt khung (trong t/h ny M =

Mt khung

t

8).

tT1 2T 3T

Hnh 2.3: Tri ph nhythi gian (THSS)

Hin nay, iu ng quan tm v cc h thng tri ph l cc ng dng a

truy nhp m nhiu ngi s dng cng chia s mt rng bng tn

truyn dn. Trong h thng DSSS, tt c cc ngi sdng cng dng chung

mt bng tn v pht tn hiu ca hng thi. My thu s dng tn hiu gi

ngu nhin chnh xc ly ra tn hiu mong mun bng cch nn ph. Cc tn

hiu khc xut hin dng cc nhiu ph rng cng sut thp ta tp m. Trong

cc h thng FHSS v THSS, mi ngi s dng c nnh mt m gi ngu

nhin sao cho khng c cp my pht no sdng cng tn s hay cng khe thi

gian cho nn cc my pht s trnh c xung t. Nh vy, FHSS v THSS l

kiu h thng trnh xung t, trong khi DSSS l kiu h thng ly trung bnh.

H thng thng tin di ng s dng DSSS nn ta ch xt n k thut tri ph

DSSS.

2.2. Gii thiu chung h thng UMTS

Nn tng ca mng GSM hin ti s c m rng thnh mng li rtrng ln c th phc v mt s lng thu bao d on trong tng lai. Cu

trc h thng UMTS hin ti ang c nghin cu, v c bn c th chia ra

nhng phn sau:


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- Mng truy cp UTRAN.

- Mng li CN.

- Thit b ca ngi s dng UE.

Hnh 2.4: Cu trc h thng UMTS

V cc phn trn c kt ni vi nhau qua cc giao din m.Cu trc h thng UMTS

K hiu:

- USIM (User Sim Card): Th Sim Card ca ngi sdng.

- MS (Mobile Station): My in thoi di ng.

- RNC (Radio Node Controller): Biu khin trmgc.

- MSC (Mobile Services Switching Center): Trung tm chuyn mch cc dchv di ng.

- VLR (Visitor Location Register): B ghi nh v tm tr.


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- SGSN (Servicing GPRS (General Packet Radio Service) Support Node):

imhi trGPRS (Dch v v tuyn gi chung) ang phc v.

- GMSC (Gateway Mobile Services Switching Center): Trung tm chuyn

mch cc dch v di ng cng.

- GGSN (Gateway GPRS Support Node): Nt h tr GPRS cng.

- HLR (Home Location Register): B ghi nh v thng tr.

- UTRAN (UMTS Terestrial Radio Access Network): Mng truy nhp v

tuyn mtt UMTS.

- CN (Core Network): Mng li.

- Hin ti tin trnh tiu chun ho UMTS ang c trin khai. Phn mng

truy nhp ca UMTS l UTRAN c chun ho. Thng 01/1998, ETSI

quytnh s dng UTRA FDD hay W-CDMA trn bng tn i v UTRA

TDD hay TD/CDMA trn bng tn n.

2.3. Mng truy nhp UTRAN

2.3.1. c tnh mng UTRAN2.3.1.1. Ph tn

Ph tn h thng thng tin di ng mtt UMTS gm:

- Bng tn kp (1929-1980 MHz ~ 2110-2170 MHz).

- Bng tn n (1910-1920 MHz ~ 2010-2025 MHz).

Di ph trn c la chn c Chu u v Nht Bn.

2.3.1.2. Hai ch kp

Trc ht ta phi phn bit c cc khi nim UTRA-FDD hay W-

CDMA v UTRA TDD hay TD/CDMA. T h thng IMT-2000, Chu u

ETSI xy dng nn h thng UMTS c giao din v tuyn l UTRAN c hai


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ch hot ng l UTRAN FDD v UTRAN TDD u sdng cng ngh nn

tng l W-CDMA. Trong khi Nht, ARIB cng xy dng nn mt h thng

3G tng tUMTS Chu u v giao din v tuyn cng c hai ch l W-CDMA v TD/CDMA cng s dng cng ngh W-CDMA lm nn tng. Nh

vy ta c th hiun gin l UTRA FDD Chu u v W-CDMA Nht l

mt, sdng bng tn kp c ng ln v xung hai di tn s khc nhau

phn chia theo tn s; cn UTRA TDD Chu u v TD/CDMA Nht l mt,

s dng bng tnn c ng ln v xung cng bng tn nhng c phn

chia theo khe thi gian.Nh vy, hai ch c nh ngha trong UTRA l FDD v TDD. C hai

chu l CDMA bng rng (W-CDMA) vi rng knh v tuyn l 5

MHz v c pht trin nhm sdng ti a hiu qu v li ch ca CDMA.

ETSI ang n lc nhm kt hp hi ho gia hai ch ny. Hin ti ETSI ch

ch trng n ch FDD v ngi ta cha r l liu TDD c c a vo h

thng UMTS pha 1 hay khng.

Tng t, t chc tiu chun Nht Bn (ARIB) cng cha coi TD/CDMA

l mt la chn d phng. TD/CDMA sc sdng trn bng tnn. Li

ch ca TD/CDMA (cng nh UTRA TDD) l kh nng qun l lu lng

khng song cng (lu lng gia ng ln v ng xung khc nhau). Bi

TD/CDMA c ng ln v ng xung trn cng mt bng tn ch phn

cch v mt thi gian, nn i vi vic truyn s liu khng cn bng gia

ng ln v ng xung, hiu qu ph ca ch TD/CDMA s cao hn sovi ch W-CDMA (n nh hai bng tn ring cho ng ln v ng

xung). Ly Internet l mt v din hnh, rt nhiu thng tin c ti xung t

cc trang WEB m rt t thng tin c gi i.


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Nh vy ta c th thy ch UTRA TDD Chu u (TD/CDMA

Nht) u im hn ch UTRA-FDD (W-CDMA Nht) tuy nhin c th

cha c trin khai ngay trong pha 1 v l do phc tp ca k thut.

2.3.1.3. Dung lng

UTRAN h trc tc bit thp v tc bit cao. Tc 384kb/s khi chuyn

ng v 2Mb/s khi cnh m bop ng nhu cu khc nhau ca ngi s

dng t thoi ti a dch v multimedia. Ngi s dng s nhn thy hiu qu

ng dng cao hn so vi cc ng dng ngy nay ang s dng trn mng di

ng. a dng tc truyn s liu cng thc hinc bng cch sdng ccphng php tri phng v tng thch nng lng truyn sng.

2.3.1.4. D liu chuyn mch gi v chuyn mch knh

Cc dch v gi a ra kh nng lun lun trc tuyn - onlinei vi

cc ng dng m khng cn chim mt knh ring bit. Cc dch v gi cng

cho php ngi dng tr tin cc trn cs tng s byte s liu trao i qua

mng m khng phi tr tin theo thi gian kt ni. UTRAN c mt ch tiu gi. N h trtruyn nhanh cc gi t xut, truyn trn knh ring khi lu

lng gi ln v lin tc. Cc dch v d liu gi rt quan trng i vi vic xy

dng cc ng dng kinh t cho truy nhp mng LAN v Internet.

Cc dch v chuyn mch knh tc cao l cn thit i vi cc ng

dng thi gian thc, v d nh hi ngh truyn hnh.

2.3.2. Cu trc hthng

H thng UTRAN bao gm mt tp cc phn h mng v tuyn RNS

(Radio Network Subsystem) kt ni ti mng li trn giao din Iu v kt ni vi

nhau trn giao din Iur. Mt phn h mng v tuyn RNS bao gm mt n v

iu khin mng v tuyn RNC (Radio Network Controller) v mt hoc nhiu


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thc thc gi l nt B (Node B). Node B c ni vi RNC trn giao din

Iub. Mi RNS chu trch nhim qun l cc v tuyn ca n.

Vi mi kt ni gia thit b ngi sdng UE vi mng UTRAN, s c mtRNS gi l RNS phc v (Serving RNS). Khi cn thit, cc RNS k cn (Drift

RNS) h trRNS phc v bng cch cung cp cc knh v tuyn. Vai tr ca

mt RNS (phc v hay kcn) l trn cstng kt ni gia thit b ngi s

dng v mng UTRAN.

RNS bao gm chc nng tch/ghp knh nhm h trs phn tp gia cc Node

B khc nhau.

Hnh 2.5: Cu trc mng UTRAN

2.3.2.1. Cu trc RNC

L phn t mng chu trch nhimiu khin cc ti nguyn v tuyn ca

UTRAN. N giao din vi CN v kt cui giao thc iu khin ti nguyn v


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tuyn RRC (Radio Resource Control), giao thc ny nh ngha cc bn tin v

cc th tc gia MS v UTRAN. N ng vai tr nh BSC.

RNC iu khin nt B thng qua giao din Iub c biu th nh l RNC iukhin CRNC (Control RNC) ca nt B. CRNC chu trch nhim iu khin ti

v trnh nghn cho cc ca mnh. Khi mt kt ni MS - UTRAN s dng

nhiu ti nguyn t nhiu RNC, cc RNC ny s c hai vai tr logic ring bit:

- RNC phc v SRNC (Service RNC) i vi mt MS l RNC kt cui c

ng Iu truyn s liu ngi s dng v c bo hiu RANAP (Radio

Access Network Application Part) tng ng t / ti mng li. SRNC cngkt cui bo hiu iu khin ti nguyn v tuyn: giao thc bo hiu gia UE

v UTRAN. N x l s liu lp 2 t / ti giao din v tuyn. SRNC cng l

CRNC ca mt nt B no c MS s dng kt ni vi UTRAN.

- RNC kcn DRNC (Drift RNC) l mt RNC bt k khc vi SRNC iu

khin cc c MS s dng. Khi cn n thc hin kt hp, phn chia

phn tp vm. DRNC khng thc hin x l lp 2 i vi s liu ti / t giao

din v tuyn m ch nh tuyn s liu trong sut gia cc giao din Iub v

Iur. Mt UE c th c nhiu DRNC.

2.3.2.2. Nt B (trm gc)

Thc hin x l lp 1 ca giao din v tuyn (m ho knh, an xen, thch

ng tc tri ph). N cng thc hin iu khin cng sut vng trong. V

chc nng n ging nh trmgc BTS GSM.

2.4. Mng li CN

- HLR l mt csd liu c t ti h thng ch nh ca ngi s dng

lu gi thng tin chnh v l lch dch v ca ngi s dng bao gm: thng


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tin v dch vc php, cc vng khng c chuyn mng v thng tin v

cc dch v b sung nh trng thi v s ln chuyn hng cuc gi.

- MSC/VLR l tng i MSC v c s d liu VLR cung cp dch v

chuyn mch knh cho UE ti v tr hin thi ca n. Chc nng ca MSC l

s dng cc giao dch chuyn mch knh CS (Channel Switch). Chc nng

ca VLR l lu gi bn sao v l lch ca ngi s dng khch cng nh v

tr chnh xc ca UE trong h thng ang phc v. Phn mng c truy nhp

qua MSC/VLR gi l vng CS.

- GMSC l chuyn mch ti im kt ni UMTS PLMN vi mng CS bnngoi.

- SGSN c chc nng ging MSC/VLR nhng s dng cho cc dch v chuyn

mch gi PS (Packet Switch). Phn mng truy nhp qua SGSN gi l vng

PS.

- GGSN c chc nng ging GMSC nhng lin quan n dch v PS.

2.5. Thit b ngi sdng UE (user Equipment)UE bao gm hai phn:

- Thit b di ng (ME Mobile Equipment) l u cui v tuyn c s

dng cho thng tin v tuyn trn giao din Uu.

- Module nhn dng thu bao UMTS (USIM UMTS Subscriber Identity

Module) l mt th thng minh cha thng tin nhn dng thu bao, thc hin

cc thut ton nhn thc v lu gi cc kho nhn thc v mt s thng tin

thu bao cn thit cho u cui.

- 2.6. Cc giao din m


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- Giao din Cu: l giao din gia th thng minh USIM v ME. Giao din ny

tun theo mt khun dng tiu chun cho th thng minh.

- Giao din Uu: l giao din v tuyn ca W-CDMA. Uu l giao din m qua

UE truy nhp cc phn tcnh ca h thng nn l giao din mquan

trng nht UMTS.

- Giao din Iu: ni UTRAN vi CN. Ging nh cc giao din tng ng

GSM: A (chuyn mch knh) v Gb (chuyn mch gi). Iu cung cp cho cc

nh khai thc kh nng trang b UTRAN v CN t cc nh sn xut khc

nhau.- Giao din Iur: cho php chuyn giao mm gia cc RNC t cc nh sn xut

khc nhau.

- Giao din Iub: kt ni mt nt B vi mt RNC. Giao din Iub cho php h tr

scnh tranh gia cc nh sn xut.

2.6. Mng truyndn

Truyn dn trn h thng UTRAN s chc chn da trn ATM. Ngi ta tho lun vic liu tiu chun UTRAN c nn bao gm clp truyn dn hay

l nn m. Ngha l, ti thi im ny mt s nh cung cp thit b mun n

phi mang tnh cht m cho php nh khai thc t do la chn. Thtc mng

li sc ng dng cho truyn dn gia cc trm thu pht v tuyn v trung

tm chuyn mch thng qua b iu khin trm gc (Iu, Iub). Vic s dng

ATM cho php mt s lng khng l cc gi d liu c truyn mt cch hiu

qu vi thi gian tr thp nht. Mt thtc ATM cho php khong 300 cuc gi

c truynng thi trn mt lung E1/T1. ATM cng thch hp vi cc mng

c s kt hp ca lu lng chuyn mch knh v chuyn mch gi.


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Lu lng gi s tng rt ln trong tng lai v mt mng chuyn mch gi l

rt cn thit. ATM c xu hng c chun ho v c s dng nh mt

phng tin chuyn chd liu v mt lp tng thch ATM mi - AAL2, c xut chun ho nhm h trcc gi nhy cm vi tr (gi mang thng tin

thoi).

Nh cp, s dng mng hin ti, mt s nh cung cp tin rng

ATM l khng cn thit v dnh a ra gii php thay th l dng trc tip IP

trn mng truyn dn SONET/SDH ch khng dng IP trn nn ATM. Vic ny

c tha n mt mng chi ph thp hn m tndng c cc k thut triph. Tuy nhin, cho n thi im ny IP vn cha chng tc s l mt tiu

chun sn sng p ng mt cch an ton cc thng tin i hi thi gian thc v

khng c tr. N cng cha chng trng s c kh nng qun l lu lng ca

chuyn mch knh.

Trong trng hp chng ta phi ph thuc hon ton vo IP, n sc

ci tin hoc lu lng chuyn mch knh s khng cn thit i vi UMTS.

Khi tt c cc thng tin thoi v cc ng dng thi gian thc s c chuyn

ch trn IP s dng th tc H.323 hin ang s dng cho Voice Over IP v

Multimedia.


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CHNG 3

CC IU KIN VK THUT, CNG NGH

CHO QU TRNH CHUYN I LN 3G

3.1. Kh nng chuyn i 2G ln 3G

3.1.1. Phn tch cc kh nng chuyn i

Bn cng ngh cellullar 2G chnh hin nay l:

- H thng GSM: theo tn gi c ngha l h thng ton cu cho in thoi di

ng, l h thng 2G xut hin u tin, c a ra vo nm 1992. GSM

da trn k thut chuyn mch knh. Dch v truyn d liu tc thp

(


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Hnh 3.1 Qu trnh chuyni t h thng 2G ln 3G

- GSM s vn l h thng ch yu ca dch v thng tin di ng Vit Nam.

- Di ph 1800 l cn thit tng dung lng.

- Thit k v quy hoch mng s ng vai tr ch cht nhm nng cao chtlng mng.

- Tnh cc cho GPRS l mt vn ni cm. Cho n thi im hin ti vn

cha a ra c tiu chun chung.

- Tnh cc cc dch v GPRS cn phi c xem xt k lng. C rt nhiu

vn lin quan ti vic tnh cc da trn lu lng.

- EDGE l con ng tin ho ti th h th ba v cng l mt b tr cho

UMTS.

- UMTS l xut ca Chu u cho thng tin di ng th h th ba. Giao din

v tuyn c la chn v s da trn cng ngh CDMA bng rng (W-

CDMA).


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- Ngi ta mong i rng cc nc Chu hinang khai thc cc h thng

GSM s i theo tiu chun 3G ca Chu u.

- i vi mng GSM hin ang hot ng 168 nc cung cp dch v cho500 triu thu bao th vic trin khai tiu chun UMTS trn nn h thng

GSM l hon ton ph hp vi quy lut t nhin.

3.1.2 Cc iu kin v nhng vn t ra cho cc bc chuyni

Vic chuyni t mng GSM ln 3G s phi kn ba kha cnh chnh c

thc hin theo s :

S chuyn iv k thut

2G S chuyn iv mng 3G

S chuyn iv dch v

Hnh 3.2. Cc kha cnh pht trin

3.1.2.1. S chuyni v kthut

S chuyni v k thut l con ng pht trin ch r phng thc trin

khai cc phn t mng v loi cng ngh thc thi k thut. y chnh l

bc pht trin trc tip theo cc xu hng chung v mt cho cng ngh.

Bi v cc phn t mng l yu t to lp nn mng, nn v mt l thuyt s

chuyni v mt k thut s tng ng vi s pht trin mng. Trong giai on

mt, do tnh cht mca cc giao din c nh ngha trong ch tiu k thut h


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thng, mng 3G c thc kt hp t nhiu chng loi thit b ca nhiu hng

khc nhau. S chuyni v k thut c th x l c iu ny tuy nhin vi

s khc nhau v tc v bc trin khai c th trong mi kt hp ca cc thitb gia cc hng khc nhau v yu cu thch ng vi cc thay i ca ch tiu k

thut 3G nn trong nhiu trng hp nu khng xem xt thuo th kt qu c

th khng nh mong mun.

3.1.2.2. S chuyni v dch v

Khc vi chuyni v mt k thut, s chuyni dch v da trn nhu cu

ca ngi sdng v nhu cu ny c th l thc t hoc ch l tng tng. ikhi cc nh khai thc mng v ch to thit b cung cp cc dch v vt qua s

k vng ca cc thu bao. R rng nu hai yu t ny khng tng ng th vic

kinh doanh cc dch v thng tin di ng s kh khn.

3.1.2.3. S chuyni v mng

Ch tiu k thut ca GSM m bo tnh mca cc giao din quytnh nn

thnh phn chun ca h thng GSM. Bi v c giao din mny, nh khai thcmng c th s dng cc thit b mng khc nhau t cc hng cung cp thit b

mng GSM khc nhau. Tnh mca giao din c th hin l n xc nh mt

cch nghim ngt cc chc nng h thng thc hin ti giao din ny, ng thi

xc nh r cc chc nng no cho php nh khai thc c th s dng trong ni

b mng ti hai pha ca giao din ny.

3.2. Cu trc h thng GSM ang tn ti

Mng li c chia ra v mta l thnh 3 mng nh hn, thao tc bi cc

trung tm khc nhau. Mng hin ti s l cskhi chuyni sang mng c tc

d liu cao hn. Vcu hnh, n gin c th chia mt mng tng th


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thnh bn phn h chnh NSS (Network Subsystem), BSS (Base Station

Subsystem), NMS (Network Management Subsystem), MS (Mobile Station):

Qun l mng (NMS)

Um A

BSS NSSMS

MSC/VLR ISDN

BTS BSC TRAU

HLR/AuC/EIR

GMSC

PSTN

PSPDN

X25

CSPDN

Hnh 3.3. Cu trc mng GSM hin ti

3.2.1. Phn hiu khin trm gc BSS

Ttc cc cuc gi c kt ni thng qua BSS. Biu khin trm gcBSC (Base Station Controller) l phn chnh ca BSS v n iu khin mng v

tuyn. BSC duy tr kt ni vi MS v kt ni vi NSS. Trm thu pht gc BTS

(Base Transceiver Station) l mt phn ca mng m bo duy tr giao din Um.

M ho v ng b tc TRAU (Transcoding and Rate Adaptation Unit) l

mt phn ca BSS, n duy tr tc m ho.

Giao din mnm gia MS v BSS l giao din Um thc hin chc nng

truy nhp v tuyn gia MS v mng di ng da trn tiu chun GSM 900 vi

ph 8MHz. Khong ph ny mang dung lng thoi trn mng vi cht

lng tt. Khi dung lng thoi v dung lng d liu tng ln, s tng ph v

tuyn l cn thitm bo tt cht lng thoi v nng cao tc truyn d


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liu. Tc d liu lun c nhn mnh trong l trnh tin n UMTS l tc

d liu trong iu kin khng c can nhiu. iu ny trong thc trt him xy

ra. Hu nh ttc cc lin ktu chu s nh hng ca mt s can nhiu trnmng v tuyn. Trong tiu chun GSM, thut ton m ho ting ni l rt hiu

qu v nhng can nhiu nh khng lm nh hng n cht lng ting ni. Khi

truyn d liu qua knh v tuyn, can nhiu xy ra nhiu hn, yu cu phi a

thm vo cc bt kim tra li. Nh vy, s bt thng tin s gim i, ni cch khc

tc d liu b gim i. Kt lun l cn c mt mng v tuyn cht lng tht

cao trc khi a ra bt k mt dch v d liu mi no.Mt gii php ng quan tm duy tr cht lng mng li khi gia tng

dung lng thoi v d liu l tng thm ph. Ph gia tng trong trng hp ny

l bng tn 1800 MHz. Bng vic sdng c bng tn 1800 MHz, chng ta c

th xy dng mng v tuyn c cu trc hai bng tn (900/1800 MHz). Bng tn

900 MHz sc dng tng kh nng ph sng v vn dng chuyn ti

thoi. Bng tn 1800 MHz s c s dng cung cp thm dung lng

chuyn ti hu ht lu lng d liu. V c nhiu knh d liu trn bng tn

1800 MHz nn c th gi thit can nhiu trn cc knh ny t i, nh vy tc

d liu s cao hn. Bng tn GSM 1800 l gii php tt tng dung lng trn

mng v c th lp t trn chnh cc BTS hay chnh cc cabinet hin c. iu

ny to cho GSM 1800 gi thnh r khi cung cp cc dch v thoi v d liu

trong tng lai.

3.2.2. Phn hiu khin chuyn mch NSS

Ttc cc cuc gi lun lun c kt ni vi nhau v thng qua NSS.

Trung tm chuyn mch MSC l mt phn ca NSS n iu khin tt c cc

cuc gi. MSC chia lm hai phn MSC/VRL c chc nng duy tr kt ni, qun


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l di ng, trao i thng tin vi BSS v GMSC c chc nng qun l thng tin

v kt ni vi nhng mng khc.

Mng li hin ti gm cc chuyn mch MSC. Nhng MSC ny chuynmch cuc gi trong ni b mng v lin kt ni vi cc mng khc. Khi chuyn

i mng ln mc tin ho hn, cc MSC s c nng cp v phn cng &

phn mm to kh nng chuyn mch lu lng d liu lu chuyn qua

mng. Thay v chuyn mch thoi v chuyn mch d liu thng thng nh

hin nay, cc MSC s chuyn mch nhiu gi d liu.

B ng k v tr tm tr VLR (Visitor Location Register) chc nngchnh l lu tr d liu thu bao, cung cp dch v v qun l di ng.

Bng k v tr thng tr HLR (Home Location Register) l ni m thng tin

v cc thu bao c lu tr cnh. Chc nng chnh ca HLR l d liu v

thu bao.

Trung tm nhn thc AuC v nhn dng thit b EIR l mt phn cu NSS

duy tr bo mt thng tin. AuC duy tr bo mt thng tin v nhn dng thu bao

cng vi VLR. EIR duy tr nhn dng thit b di ng (phn cng) lin kt vi

thng tin bo mt cng vi VLR.

Tn chung cho trung tm dch v gi node mng tng ng l phn dch

v gi tr gia tng VAS (Value Additional Service):

Phn cng dch v gi tr gia tng. VAS n gin nht cng gm hai loi

thit b: trung tm dch v tin ngn SMSC (Short Message Service Center) v h

thng th thoi VMS (Voice Mail System). V mt k thut, VAS m bo cung

cp mt s loi dch v nhtnh bng cch s dng cc giao din chun vi

mng GSM v n c th c hoc khng c cc giao din ra cc mng khc. Trn


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quan im pht trin dch v, VAS l bc u tin to doanh thu vi cc

dch v gi tr gia tng trn mng GSM.

Khi nim mng thng minh IN (Intelligent Network) c tch hp cngvi mng GSM. V mt k thut, n lm thay i cbn cc phn t ca mng

chuyn mch nhm thm vo chc nng IN, ngoi ra bn thn mng IN l mt

b phn tng i phc tp. IN c kh nng pht trin dch vhng ti tnh c

nhn v nh khai thc mng c th nhIN m bo an ton kinh doanh, v d,

cc thu bao tr trc hu ht c trin khai nhcng ngh IN.

3.2.3. Phn h khai thc v bo dng mng NMSNMS l phn khai thc v bo dng mng. N cng cn cho vic iu khin

mng. Vic theo di vn hnh v cht lng bo dng v cung cp dch v ca

mng thng qua NMS.

3.2.4. Phn h my con MS

MS l t hp ca thit bu cui ME v module nhn dng dch v ca thu

bao SIM.

MS = ME + SIM.

3.3. Giai on HSCSD

Trong giai onu, thu bao GSM sdng ng truyn d liu chuyn mch

gi, i xng vi tc 9,6 Kb/s. Do sc p ca Internet v th in t ln

ng truyn d liu di ng tng nhanh, hn na thc t cho thy s pht trin

ny bnh gi qu thp ti thi im thit k mng GSM.

Hin nay v mt k thut c hai gii php sau:

- Ti u tc m ho knh. Thc hinc vic ny ta lm tng tc bit

t 9,6 Kb/s ln 14,4 Kb/s.


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- Lm cho d liui qua giao din Um nhiu hn bng cch s dng mt vi

knh lu lng thay v mt knh. Gii php ny c gi l d liu chuyn

mch knh tc cao HSCSD (High Speed Curcuit Switched Data) nh hnhv.

Qun l mng (NMS)

Um A

BSS NSSMS

BTS BSC TRAU MSC/VLR GMS ISDN

PSTNPSPDN

X25

Thay i HW& SW cho SCSD

HLR/AuC/EIR V iA nS

CSPDN

Hnh 3.4. Mng d liu chuyn mch knh tc cao - HSCSD

Trong mi trng ti u, mt thu bao HSCSD c th t n tc

truyn d liu 40-50Kb/s. Gii php k thut ny c hn ch l lng ph ti

nguyn v gi cc s cao hn. Vic s dng gii php HSCSD ph thuc rt

nhiu vo chnh sch gi ca nh khai thc mng. Mt vn khc l phn ln

lu lng d liu v bn cht l khng i xng, in hnh l dng ng truyn

tc thp t thit bu cui n mng (ng ln) v dng tc cao cho

ng ngc li (ng xung). V mt k thut, giao din chuyn mch knh

khng i xng Um khng phi l mi trng truy nhp tt nht cho kt ni d


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liu. iu ny t ra yu cu phi nng cp mng GSM nhm thch hp hn cho

vic truyn d liu mt cch hiu qu.

3.4. Giai on GPRSGPRS l cu ni gia h thng thng tin GSM th h 2 v th h 3.

GPRS l mt dch v s liu chuyn mch gi trn csh tng GSM. Cng

ngh chuyn mch gi c a ra ti u vic truyn s liu cm v toiu

kin truyn ti cho mt lng d liu ln.

V mt l thuyt, GPRS c th cung cp tc s liu ln n 171 kbps

giao din v tuyn, mc d cc mng thc t khng bao gic tht c tc ny (do cn phi dnh mt phn dung lng cho vic hiu chnh li trn

ng truyn v tuyn). Trong thc t, gi tr cc i ca tc ch cao hn 100

kbps mt cht vi tc kh thi thng vo khong 40kbps hoc 50 kbps. Tuy

nhin, cc tc ni trn cng ln hn nhiu so vi tc cc i GSM.

GPRS m bo tc s liu cao hn nhng vn s dng giao din v

tuyn ging GSM (cng knh tn s 200 KHz c chia thnh 8 khe thi gian).

Tuy nhin bng GPRS, MS c th truy nhp n nhiu khe thi gian hn.

Ngoi ra, m ha knh ca GPRS cng hi khc vi m ha knh ca

GSM. GPRS nh ngha mt s s m ha knh khc nhau. S m ha

knh thng c dng nht cho truyn s liu gi l S m ha (Coding

Scheme) 2 (CS-2). S m ha ny cho php mt khe thi gian c th mang s

liu tc 13,4 kbps. Nu mt ngi s dng truy nhp n nhiu khe thi

gian th c thtn tc 40,2 hay 53,6 kbps. S ny m bo hiu chnh

li kh tt giao din v tuyn. Mc d CS-3 v CS-4 cung cp thng lng cao

hn, nhng chng nhy cm cao vi li giao din v tuyn. Thc ra CS-4 hon

ton khng m bo hiu chnh li giao din v tuyn. CS-3 v c bit l CS-


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4 i hi truyn li nhiu hn giao din v tuyn, v th thng lng thc s

hu nh khng tt hn CS-2.

Cc tc giao din v tuynbng trn m bo cc tc s liu khcnhau ca ngi s dng giao din ny. Tuy nhin, c nhiu lp cao hn giao

din v tuyn cng tham d vo vic truyn s liuGPRS. Mi lp b sung

thm thng tin vo s liu nhn c t lp trn. Lng thng tin b sung do

tng lp to ra ph thuc vo nhiu yu t, trong yu t d nhn thy nht l

kch cca gi ng dng cn truyn. i vi mt lng s liu cn truyn cho

trc, cc kch cca gi s liu ng dng nh hn s dnn thng tin b sungln hn cc kch c ca gi s liu ln hn. Kt qu l tc s liu c th s

dng c thp hn tc s liu giao din v tuyn 20-30%.

Tt nhin u imln nht ca GPRS khng chn gin l ch n cho

php tc s liu cao hn. u im ln nht ca GPRS l n s dng cng

ngh chuyn mch gi. iu ny c ngha l mt ngi sdng ch tiu ph ti

nguyn khi ngi ny cn truyn hoc nhn s liu. Nu mt ngi s dng

khng pht s liumt thi im th cc khe thi gian giao din v tuyn ti

thi im ny s c dnh cho cc ngi s dng khc.

Vic GPRS cho php nhiu ngi s dng cng chia s ti nguyn v

tuyn l mt u im ln. iu ny c ngha rng mi khi mt ngi s dng

mun truyn s liu th MS phi yu cuc truy nhp n cc ti nguyn ny

v mng phi cp pht cc ti nguyn ny trc khi xy ra truyn s liu. Mc d

iu ny c v nh nghch l vi vic dch v lun lun c kt ni nhngGPRS hot ng sao cho th tc yu cu-cp pht khng b pht hin, v th

ngi s dng v dch v dng nh lun lun c kt ni.


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GPRS ph hp vi mt phm vi rng cc ng dng t th in t (E-

mail), vn phng di ng (Mobile Office), cc ng dng o lng lu lng t

xa, ti tt c cc ng dng d liu cm, chng hn nh truy cp Internet. GPRScho php h tr cc ng dng d liu ca mng cnh hin ti trn cc u cui

di ng. Dch v GPRS c nh hng ch yu cho cc ng dng vi cc c

tnh lu lng ca truyn ti chu kvi khi lng nh v truyn khng theo

chu k ca cc d liu c kch nh hoc trung bnh. iu ny to kh nng cho

h thng c th phc v cc dch v v ng dng mi. S truyn ti mt lng

ln d liu vn sc duy tr qua cc knh chuyn mch knh trnh trngica ph v tuyn gi. Cc ng dng ca GPRS c th tin hnh t cc cng c

thng tin trong mt my tnh xch tay PC (thin t, truyn dn file v hin th

trang web (www)) n cc ng dng c bit lin quan ti cc truyn ti thp

(my o t xa, iu khin lu lng ng st v ng giao thng, thng tin

iu hnh taxi v xe ti, hng dn ng ng lc v giao dch tin t...).

V lc u GSM c thit k cho lu lng chuyn mch knh, nn vic

a dch v chuyn mch gi vo i hi phi b sung thm thit b cho mng

(hnh 7). Mng GPRS kt ni vi cc mng s liu cng cng nh IP v mng

X.25. Nt h trGPRS phc v (SGSN) v nt h trGPRS cng (GGSN) thc

hin nhn v truyn cc gi s liu gia cc MS v cc thit bu cui s liu

c nh ca mng s liu cng cng (PDN). Nt GGSN cn cho php truyn

nhn cc gi s liun cc MS cc mng thng tin di ng GSM khc.

Giao din v tuyn ca GPRS s dng cc tnh nng cbn ca giao din

v tuyn GSM. Nh vy, cdch v chuyn mch knh v chuyn mch gi u

c th sdng cng sng mang. Tuy nhin, mng ng trc ca GPRS c

thit k sao cho n khng ph thuc vo giao din v tuyn.


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Tnh cc vn l mt ch mi vi ETSI. Vic tnh cc s c th mra

i vi cc nh khai thc mt phng php lun mi, l tnh cc cho thu

bao da trn khi lng d liu truyni/ nhn v thay v cho vic tnh cctruyn thng l da trn n v thi gian.

Qun l mng (NMS)

Um A

BSS NSSMS

BTS BSC TRAU MSC/VLR GMSC ISDN

PSDN PSPDNX25

Thay i HW& SW cho GPRSHLR/AuC/EIR V I

A N

S

CSPDN

Gb

Mng li giGPRS

SGSN GGSN Mng d liu khc

Internet

3.5. Giai on EDGEHnh 3.5. Cu trc mng GPRS

Mt k thutiu ch mi c th p dng ti giao din v tuyn l 8-PSK

sao cho mt k t c th mang mt t hp 3 bit thng tin v do vy tc bit s

c ci thin ng k. Khi k thut ny c kt hp vi cc k thut m ha

knh phc tp, ngi ta c th tc tc d liu 48 kbps so vi 9,6 kbps

cho mt knh GSM truyn thng v trong trng hp ny mt bit thng tinchnh l mt k t ti giao din v tuyn. K thut lm tng tc d liu trn

c gi l EDGE (Enhanced Data Rates for Global/GSM Evolution) nh hnh

v.

S pht trin ca EDGE chia lm hai giai on:


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EDGE giai on 1 c bit nh l E-GPRS (Enhanced GPRS). Cng nh vy

BSS i thnh E-RAN (Mng truy nhp v tuyn EDGE). Giai on 1 EDGE

xc nh cc phng php iu ch v m ha knh nhmtc tc dliu ln n 384 Kb/s cho lu lng chuyn mch gi di cc iu kin xc

nh. Gi thit y l mt thit b u cui khi c 8 khe thi gian ca giao din

Um s cho mt ng kt ni tc 8 x 48 Kb/s = 384 Kb/s. Ngoi ra, thit b

u cui EDGE phign BTS s dng tc m ho knh cao hn.

Qun l mng (NMS)

Um

MS

BTS BSC

A

TRAU MSC/VLR

NSS

GMSCISDN

PSTNPSPDN

X25

HLR/AuC/EIR V IA NS

Gb

CSPDN

Li mng gi E-GPRS

SGSN GGSN Mng d liu khc

Internet

Hnh 3.6. Cu trc mng EDGE

EDGE giai on 2 c tn thng mi l E-HSCSD v nhmtc tc

truyn d liu trn cho cc dch v chuyn mch knh.ng trn quan im pht trin mng th ni chung cng ngh EDGE c

cu im v nhc im. u im chnh ca cng ngh ny l c th tc

tc truyn d liu gn nh tng ng vi yu cu ph sng vng th


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ca cng ngh UMTS. Nhc im l tc d liu ny kh tc cho ton

b cc thu bao trn ton cell ph sng. Nu yu cu cho ton b mt vng vi

cng ngh EDGE th chc chn s lng cell ph sng trong vng ny s phitng ln ng k. Ni cch khc, EDGE l gii php t gi v cng ngh s

dng cho mt s trng hp. Tng lai ca cng ngh EDGE theo kha cnh ny

cn phi c kim chng khi n phi thc s cnh tranh vi cc gii php cng

ngh thc s ca 3G.

Giao din EDGE tn dng tc bit cao hn tc trn hthng di ng

hin thi. tng tc bit trn giao din v tuyn, mt phng thc iu chmi c a ra. 8-PSK l phng thc c la chn v n cung cp tc d

liu cao, hiu qu ph cao v phc tp lpt va phi. Tc t m c

gimc 271 ksp/giy dnn tc bit tng t 22.8 kbit/s ln 69.2 kbit/s trn

mt khe thi gian.

Mc ch l ti s dng cc dng dch v d liu GSM thng thng.

Bng vic ti sdng cu trc ca GPRS, dch v chuyn mch gi c cung

cp vi giao din v tuyn trong tc bt bin i t 11.2 n 69.2 kbit/s

trn mt khe thi gian. Cc dch v chuyn mch thng thng c h trvi

tc trn giao din v tuynt n 28.8 kbit/s. i vi tt c cc dch v, s

dng a knh thi gian c h tr thu c 8 ln tc bit cung cp bi 1

khe thi gian n, to nn tc nh i vi chuyn mch gi l 554 kbit/s.

Nhn thy h tng GSM c s dng hiu qu, ch c giao din A-bis

cn c s thay i cht t. Mt im quan trng l s ph sng v k hoch tns khng cn thit c thay i khi c hin din ca EDGE. Thm na, v cc

knh vt l EDGE c thc sdng cho c cc dch v GSM chun, khng

cn c s phn chia cnh cc knh gia cc dch v.


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Trn y l gii thiu tng quan v EDGE. Cc m phng cng chng t rng

EDGE c th chia s ph vi GSM/GPRS vi cht lng tt cho c hai loi thu

bao. Cht lng da trn iu khin cng sut c th ci thin hn na chtlng ca thu bao.

Bt li ca EDGE ch t l m ho tng ln lm tng nhiu phc tp

khi s dng mch trung ho ti u. T l bit tng ln so vi GSM/GPRS chun

cng gim th i vi tnh ri rc thi gian v vn tc di chuyn ca thu bao

di ng. Gin iu ch mi 8-PSK i lp vi gin GMSK, khng c

ng bin bao khng i, yu cu phi c tuyn tnh ca khuch i cngsut. c biti vi cc thit b c cng sut ra ln, kh ch to cc my thu

pht gi r vi iu kin s dng trn vn ph GSM. Nh vy, thit k cc

my thu pht sdng cho trm macro cell, cn th thch a ra 8-PSK.

EDGE cng c th xem xt nh mt gii php k thut cho cc nh khai

thc khng shu bt k mt giy php no v UMTS.

3.6. Giai on UMTS

iu kin trin khai l nhu cu dch v d liu chim phn ln trong lu

lng. trin khai mng mt cch nhanh chng v hiu qu, h thng phi

tng thch ngc vi mng li GSM -MAP ca GSM. Chung h thng bo

hiu, u cui di ng c th chuyn vng vi h thng GSM hin c. iu ny

i hi phi c my cm tay hai ch GSM/GPRS hoc

GSM/GPRS/WCDMA.

C ba chun ha c thng qua ca vic chuyni 3GPP:

- 3GPP R99

Phng n chuyni ny nhm tndng ti a h tng GSM v GPRS hin c.

Mng li ca 3G c c phn chuyn mch gi v chuyn mch knh


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Mng truy nhp v tuyn ca 3G c th ni c vi phn chuyn mch knh ca

GSM sau khi c phn b sung cho 3G. Phn mng li vi hai nt mng

SGSN v GGSN ca GPRS trc y c s dng li hon ton.Nh vy phng n ny ph hp cho th trng c c dch v yu cu chuyn

mch knh v dch v d liu gi.

- 3GPP R4

Phn gi vi GGSN v SGSN vn gi nguyn. Trung tm chuyn mch di ng

MSC ca h thng c tch tnh hai phn: Phn iu khin chuyn mch v

cng a phng tin (thc hin chc nng chuyn mch). Mt b iu khin cth qun l c rt nhiu cng chuyn mch a phng tin.

- 3GPP R5

y l gii php s dng mng li ton IP, c thc truyn trn ATM. Nh

vy vi tr ca ca mng truy nhp v tuyn ch l thnh giao din v tuyn ca

3G. Mng li IP c th tng thch vi bt k cng ngh truy nhp v tuyn no.

Nh vy, cng ngh ny s ph thuc rt nhiu vo s pht trin ca VoIP.


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CHNG 4

CC PHNG N CNG NGH V

GII PHP PHT TRIN MNG 3G CHO VIETTEL

4.1 Gii thiu v cng ty Viettel Telecom

Cng ty Vin thng Viettel (Viettel Telecom) c thnh lp ngy

05/4/2007, trc thuc Tng Cng ty Vin thng Qun i (Viettel) trn csst

nhp cc Cng ty Internet Viettel, in thoi c nh Viettel v in thoi di

ng Viettel. Viettel Telecom cung cp a dch v vin thng, vi dch v ding Viettel l nh cung cp dch v s 1 Vit Nam, c vng ph ln nht vi

quan im ph sng n 90% din tch lnh th v 97% dn c, h tng mng

ln nht vi trn 11.000 trm BTS (tnh n 20/9/2008), hthng tng i dung

lng m bo phc v cho 50 triu thu bao n nm 2010. Cht lng mng

lui tt nht vi cc ch s KPI t v vt tiu chun ngnh ngang tm khu vc

v th gii. S lng thu bao ln nht tnh n 20/9/2008 Viettel c trn 25triu thu bao hot ng, ln hn doanh nghip ng th hai trn 50% v ng

th 56/648 nh cung cp dch v vin thng ca th gii theo t chc Wireless

Intelligence mt t chc uy tn v thng k vin thng a ra cc s liu

nh gi.

4.2. nh gi v csh tng mng hin c

4.2.1. Cu trc mng hin ti

Mng Viettel hin ti c xy dng trn tiu chun GSM v ang trong

qu trnh nng cp, mng li vi vic truyn ti all IP, trin khai mng MPBN

(mng IP core cho di ng) m bo cho cc tng i Soft Switch c truyn

ti trn nn IP, c 80% cc tng i ang hot ng l tng i Soft Switch,


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m bo vic IP ha mng li l bc m cho vic nng cp mng ln 3G v

l cstin n mng IMS.

Nng lc hin ti ca mng ViettelMSC

BSC Trm BTSTngs

CellSlngDung

lng

Khu vc 1 22 16 triu 55 4.910 14.630

Khu vc 2 8 5 triu 25 1.458 4.274

Khu vc 3 20 14 triu 80 4.720 14.360

Tng 50 35 triu 160 11.088 33.264

Cu trc mng hin ti

Hnh 4.1 Cu trc mng Viettel hin ti


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4.2.1.1. Mng chuyn mch

Bao gm: 10 tng i GMSC l tng i cng giao tip vi mng ngoi v

hon ton l tng i Softwitch. 50 tng i chuyn mch di ng VMSC trong

c 80% l tng i Softwich, mng li IP ha ton mng sn sng cho vic

nng cp ln 3G. Mng bo hiuc lp vi mng lu lng vi cc STP ti cc

khu vc 1, 2, 3 tng ng ti 3 trung tm H Ni, Nng, H Ch Minh.

4.2.1.2. Mng Truyn dn

c phn thnh 4 lp: ng trc quc gia v quc t, mng lin tnh,

mng ni tnh v mng truy nhp. Tng s Node truyn dn trn 9000 nodequang vi chiu di cp quang trn 40.000 km, sdng cng ngh DWDM v

SDH c dung lng ln v c to thnh cc vng Ring m bo an ton

mng. Cc trm BTS di ng c kt ni v BSC 70% bng cp quang v 30%

l bng Viba v Visat.

4.2.1.3. Mng V tuyn

Mng truy nhp v tuyn gia my u cui v mng di ng da trn tiuchun GSM 900 vi ph tn 8MHz. Khong ph tn ny mang dung lng

thoi trn mng vi cht lng tt. Khi dung lng thoi v dung lng d liu

tng ln, s tng ph v tuyn l cn thit m bo tt cht lng thoi v

nng cao tc truyn d liu. Tc d liu lun c nhn mnh trong l

trnh tin n UMTS l tc d liu trong iu kin khng c can nhiu. iu

ny trong thc trt him xy ra. Hu nh tt cc lin kt u chu s nh hng

ca mt s can nhiu trn mng v tuyn. Trong tiu chun GSM, thut ton m

ho ting ni l rt hiu qu v nhng can nhiu nh khng lm nh hng n

cht lng ting ni. Khi truyn d liu qua knh v tuyn, can nhiu xy ra

nhiu hn, yu cu phia thm vo cc bt kim tra li. Nh vy, s bt thng


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tin s gim i, ni cch khc tc d liu b gim i. Kt lun l cn c mt

mng v tuyn cht lng tht cao trc khi a ra bt k mt dch v d liu

mi no.Mt gii php ng quan tm duy tr cht lng mng li khi gia tng

dung lng thoi v d liu l tng thm ph. Ph gia tng trong trng hp ny

l bng tn 1800 MHz. Bng vic s dng c bng tn 1800 MHz, chng ta c th

xy dng mng v tuyn c cu trc hai bng tn (900/1800 MHz). Bng tn 900

MHz s c dng tng kh nng ph sng v vn dng chuyn ti thoi.

Bng tn 1800 MHz sc s dng cung cp thm dung lng chuyn tihu ht lu lng d liu. V c nhiu knh d liu trn bng tn 1800 MHz nn

c th gi thit can nhiu trn cc knh ny t i, nh vytc d liu s cao hn.

Bng tn GSM 1800 l gii php tt tng dung lng trn mng v c th lp

t trn chnh cc BTS hay chnh cc cabinet hin c. iu ny to cho GSM

1800 gi thnh r khi cung cp cc dch v thoi v d liu trong tng lai.

4.2.2. nh gi chung v trin khai nng cp mng Viettel ln 3G

1. S ra i ca h thng thng tin di ng GSM l mt bc nhy vt ca lnh

vc thng tin, mang li cho ngi sdng nhiu li ch kh c th ph nhn.

Cng vi s pht trin ca k thut hin i, si mi cng ngh, thng tin di

ng cng ngy cng i mi theo chiuhng tch cc. Trong tin trnh ca s

pht trin khng ngng , xu hng trin khai 3G l mt xu hng tt yuang

dn c trin khai ti nhiu nc trn th gii. Vi nhiu cng ngh thng tin

di ng th h 2 hin ang tn ti, vic trin khai v hi t ti mt cng nghduy nht 3G l cc k kh khn. Ngi ta a ra cc l trnh khc nhau cho

cc cng ngh 2,5G hin ang tn ti. i vi GSM, y l cng ngh 2,5G ph


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bin trn ton cu nn cc nh sn xut, cc t chc tiu chun th gii cng c

bit ch trng trong vic nng cp ln 3G.

ng trc tnh hnh th trng cng nh h tng csmng thng tin ding Vit Nam cha tht s ln mnh, vic pht trin h thng thng tin di

ng GSM Vit Nam to ra mt bc t ph ln trong ngnh cng nghip

vin thng ni chung v ngnh vin thng di ng ni ring. Trong giai on

ny, cht lng dch v thoi truyn thng vn l mi quan tm hng u ca

khch hng. Bn cnh , sa dng v dch v phn no p ng c nhu

cu ca khch hng.Tuy nhin, s pht trin nhanh chng ca cc dch v s liu m trc ht

l s bng n ca Internet trong nhng nm gny i hi cc nh khai thc

mng thng tin di ng Vit Nam, trong c nh khai thc mng Viettel phi

c nhng mc tiu chin lc, ph hp vi hon cnh ring ca nc mnh

pht trin ln h thng thng tin di ng th h ba.

Th nht, mng Viettel c xy dng trn cscng ngh GSM. Ngoi

di ph 900, di ph 1800 thc s cn thit tng dung lng. Bn cnh ,

vic thit k v quy hoch mng nhm nng cao cht lng mng; vic thng

xuyn nng cp v mrng mng nhm p ng nhu cu th trng v s pht

trin cng ngh trn th gii lun ng vai tr cc k quan trng.

Th hai, thit b trn mng Viettel ch yu do hai nh cung cp l Alcatel,

Ericsson, Nokia v Huawei. y l nhng nh cung cp hng u v thit b vin

thng, trong c bit phi kn thit b mng thng tin di ng. Trong tintrnh pht trin khng ngng v mt cng ngh thng tin di ng trn th gii,

Alcatel, Ericsson, Nokia v Huawei c s nghin cu, phn tch v cng


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chn cho mnh mt xu hng pht trin ng n: GSM - GPRS/EDGE -

WCDMA.

T nhng l lun trn y, l trnh pht trin ca mng Viettel t GSM tinln th h th ba WCDMA l mt hon ton hp l v c cs:

- Da trn nn tng sn c v th trng v csh tng tng i mnh ca

h thng GSM, mng GSM hon ton hi t iu kin tin ha ln cc

th h thng tin di ng 2,5G (GPRS/EDGE) v 3G (WCDMA) m vn khai

thc ti a ti nguyn sn c ca mng li, tn dng ti a hiu qu ca

thit b u t.- V my u cui, s dng cc my u cui hai ch WCDMA/GSM vi

GSM tn dng vng ph sng v vi WCDMA s dng cc tnh nng

dch v mi - Viettel s c th trin khai cc dch v bng rng trn mng

GSM mt cch trong sut. Ni chung s c rt nhiu my u cui ra i l

s kt hp ca cc tiu chun cng ngh khc nhau nhm mc ch nh mt

cu ni gia cng ngh.y chnh l mt trong nhng yu t tng trung

thnh ca khch hng i vi mng li v tnh cnh tranh.

2. Theo don ca cc chuyn gia, cho n nay v c th trong nhiu nm ti

dch v thoi truyn thng s vnng vai tr ch cht v bn cnh l s tng

trng ngy cng ln mnh v nhu cu dch v s liu, in hnh l dch v tin

nhn trn th trng Vit Nam. Do vy, s pht trin song song gia dch v

thoi v dch v phi thoi s tt yu tn ti trong mt thi gian di.

3. GPRS s l cu ni gia h thng thng tin di ng th h 2 v th h 3. Vic

u t h thng GPRS l thc s cn thit nhm tng bc trin khai h thng

thng tin di ng th h th 3 trn mng. y cng l xu hng tt yu m cc


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nh khai thc thng tin di ng phi thc hin nhm gi vng th trng v tng

cng kh nng cnh tranh.

GPRS c mt s li ch nh sau:i vi nh khai thc:

- Gim chi phu t: Mt trong nhng gii php tt ti u v mt cng ngh

ca mng GSM l c kh nng cung cp cc dch v s liu di ng cao cp

(truyn s liu tc cao) m khng phi xy dng mt mng hon ton

mi. Thng qua vic trin khai GPRS, nh khai thc dch v c th nng cp

h thng GSM ca mnh tin ti h thng thng tin di ng th 3,bi GPRScho php cng tn ti song song vi mng GSM, tn dng ti a kh nng v

ngun ti nguyn ri ca thit b hin c trn mng GSM.

- Sau khi trin khai GPRS, vic tnh cc s dng dch v ca khch hng c

thi gian truy cp h thng (nhng phng php tnh cc truyn thng)

hoc da trn nguyn tc theo thi gian da trn nguyn tc tnh theo dung

lng d liu c truyn qua h thng hoc kt hp c hai phng php.

iu ny lm cho dch v thng tin di ng cng tr nn hp dn khch

hng, khng nhng p ng nhu cu s dng dch v tc cao ca khch

hng m cn cung cp kh nng la chn v ph s dng dch v sao cho ph

hp. chnh l tnh mm do v linh hot trong phng n tnh cc s

dng dch v mi m GPRS h tr.

- Thng qua GPRS, nh cung cp dch v c chi tt khai thc th trng

ng dng mi. T c th nng cao doanh thu v li nhun.

- Vi nhiu tnh nng ng dng s hp dn khch hng mi v tng lng trung

thnh ca cc khch hng c.

- Nng cao hiu qu s dng v tuyn thng qua vic phn b knh linh hot.


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- Giao din tiu chun v m, c th d dng tch hp vi thit b ca cc nh

cung cp khc nhau.

- Bng rng ca GPRS c tht n 50 kbps ph thuc vo dung lng tica mng li v thit bu cui.

i vi ngi s dng:

- GPRS cho php ngi sdng lun trng thi truy nhp online.

- Tc truyn d liu tc cao c tht ti 115 kbps. Do c th

nhn v gi e-mail ngay tc thi.

- C th d dng thit lp kt ni.- C th sdng ngun thng tin di do thng qua h trcho a giao thc

bao gm c giao thc IP.

- Vn c th gi v nhn cuc gi, nhn v gi SMS m khng nh hng n

vic sdng GPRS truy cp thng tin.

- Ch phi tr cc cho d liu trao i, khng phi tr cc cho thi gian truy

cp.

- C th khng nh mng th h 2,5 GPRS s pht trin trong mt thi gian

di. GPRS s c mrng khp trn ton quc dn dn c c s chp

nhn ca khch hng i vi cc dch v phi thoi.

4. Tip theo vic trin khai GPRS s l EDGE nhm tng kh nng truyn s

liu ln 384kbps c kh nng cung cp cc dch v thin t, dch vnh

v trn bn , dch v truy cp thng tin d liu, gii tr... Thun li ca vic

trin khai EDGE l:

- Trc ht, EDGE khng cn phi s dng bng tn mi.

- Da trn csh tng sn c ca trin khai GPRS, vic pht trin ln giai

on EDGE tit kimc chi phu t. Do ch thay i k thutiu ch


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v tuyn 8-PSK nn EDGE vn gi nguyn cu trc ca mng c m ch cn

nng cp phn mm v thm cc TRX mi c kh nng EDGE.

EDGE l con ng tin ha ti th h th ba v cng l mt b tr choWCDMA. EDGE tng cng c cc kh nng truyn s liu ca mng

GSM/GPRS, h trtc s liu ln ti 384 kbps - mt tc s liu ca mng

th h ba. Do vy, c th ni EDGE s to mt bc m quan trng tin ti

mng WCDMA.

Tuy nhin, s phnng ca khch hng i vi cc dch v s liu trn nn

cng ngh chuyn mch gi ca GPRS (truy nhp Internet, Intranet, MMS,WAP, Games on line...) s l yu t quytnh con ng pht trin tip theo

ca h thng. Nu nhu cu v dch v s liu ca khch hng tng trng mnh

m, c th giai on pht trin ln EDGE c b qua.

5. Ty, vi ti nguyn tn s 3G sn c, vic trin khai WCDMA trn nn h

thng GSM l hon ton ph hp vi quy lut t nhin. Trn csca mng li

GPRS c pht trin, vic xy dng h thng WCDMA v cbn l xy

dng phn cng cho mng truy nhp v tuyn UTRAN gm RNC v Node B.

Mt iu chc chn l WCDMA cha th trin khai ti tn cc vng xa, m

trc mt s tp trung pht trin mt s thnh ph ln. Khi , my u cui

ca khch hng s c kh nng tng thch gia hai h thng GSM v WCDMA.

Nh vy, l trnh t GSM ln WCDMA theo cng ngh WCDMA tng i r

rng m bo s kt hp cng tn ti gia mng GSM hin ti v mng 3G ng

thi cng tn dng c rt nhiu li th ca mng GSM hin c nh li th v

s thu bao ang c, thi quen ca khch hng v s dng cc dch v truy nhp

Internet khi trin khai GPRS v li th trong vic trin khai roaming quc t.

Hin nay s lng thu bao GSM ngy cng pht trin nhanh v chim th phn


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rt ln trong tng s thu bao di ng, iu cho thy khi la chn l trnh i

ln WCDMA da trn WCDMA cng s to ra li th trong vic trin khai

roaming quc t. Ngoi ra, vic la chn WCDMA lm nh hng cng nghWCDMA cn c mt sli th nh sau:

- Hiu qu sdng ph tn rt cao.

- Cho php sdng cc my u cui cng sut thp.

- Cho php cung cp cc ng dng khc nhau vi cc tc truyn s liu

khc nhau.

- Ton b ph tn s dng cho WCDMA nh sau:WCDMA TDD: 1900 MHz - 1920 MHz v 2020 MHz - 2025 MHz.

WCDMA FDD:

+ ng ln (Uplink ) : 1920 MHz - 1980 MHz.

+ ng xung (Downlink ) : 2110 MHz - 2170 MHz.

4.3 Phn tch cc phng n v la chn gii php

C ba phng n la chn khi chuyn t mng GSM ln mng 3G cho

Viettel.

- Phng n trin khai 3G theo chun 3GPP R99



4.3.1 Phn tch cc phng n

4.3.1.1 Phng n 3G theo chun 3GPP R99


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Qun l mng (NMS)Um

A

MS E-RAN CN CS Domain ISDNBTS BSC 3G MSC/VLR 3G GMSC

PSTNPSPDN

X25

Iu

Uu Gb

HLR/AuC/EIR VAS

C W M UA A E SM P X AE E TL

CSPDN

UE UTRANCN PS Domain

BS RNC SGSN GGSN Mng dliu khc

Internet

Hnh 4.2 Mng 3G theo chun 3GPP R99

3G a ra phng php truy nhp v tuyn mi W-CDMA. W-CDMA v

nhng bin th ca n mang tnh ton cu, do tt c mng 3G c th chp

nhn vic truy nhp bi thu bao mng 3G bt k. Ngoi tnh ton cu, W-

CDMA c nghin cu rt k trong phng th nghim v chng tc

hiu qu s dng ph tt hn (trong cc iu kin xc nh) v ph hp hn cho

vic truyn d liu gi so vi cc truy nhp v tuyn trn csTDMA. Cng

ngh W-CDMA v cc thit b truy nhp v tuyn ca n khng tng thch vi

cc thit b mng GSM, iu gii thch ti sao khi thm W-CDMA vo mng

li cn thm mt s thnh phn mi nh RNC (Radio Network Controller) v BS

(Base Station).

Mt khc, mt trong cc yu cu cbn ca UMTS l kh nng hotng

ng thi GSM/UMTS, v d nh vic chuyn giao gia hai h thng khi truy


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nhp v tuyn thay i t GSM sang W-CDMA v ngc li trong mt cuc gi.

Kh nng ny i hi hai yu cu c th l:

- Th nht, giao din din v tuyn GSM phi thay i sao cho c th phtqung b cc thng tin h thng v mng v tuyn W-CDMA ti ng

xung. ng nhin mng truy nhp v tuyn W-CDMA cng c th pht

qung b thng tin h thng v mng GSM ting xung.

- Th hai, nhm gim thiu chi ph khai thc, cc ch tiu k thut qui nh

trong 3GPP cho kh nng m bo c cc chc nng lin mng ca h

thng cc MSC/VLR 2G nng cp c th x l c truy nhp v tuynbng rng, UTRAN.

- Cho ti hin nay, khi nim IN c pht trin trc tip t mng

PSTN/ISDN v do vy chc chn s c mt vi nhc im khi cha cp

trc tip cho mng di ng. Vn ch yu vi cng ngh IN chun l

khng th truyn cc thng tin v dch v gia cc mng. Ni cch khc, nu

mt thu bao s dng cc dch v trn csIN th cc dch v ny chc

cung cp tt trong mng thng tr ca thu bao. Tnh hung ny c th

c ci thin bng cch s dng cng ngh IN nng cp c gi l

CAMEL (Customised Application for Mobile Network Enhance Logic).

Cng ngh CAMEL c th truyn thng tin dch v gia cc mng v vai tr

ca cng ngh ny s tng ln khi trin khai 3G, lc hu nh mi hot

ng qua mng 3G u t nhiu c s tham gia ca CAMEL.

Cc kt ni truyn dn trong mng truy nhp v tuyn W-CDMA c thc

hin bng cch dng ATM (3GPP R99). D n tiu chun ha FRAMES tho

lun rt nhiu v vic c sdng ATM cho mng 3G hay khng v cui cng

quytnh s dng ATM c da trn hai l do sau:


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- Kch thc cell v ti lu lng khi s dng ATM l tng i nh do c

u im gim c b nhm lu tr thng tin. Trong trng hp ngc

li, khi phi nhm nhiu thng tin th ng nhin tr s tng, ng thiti lu lng tnh cc thit b nh m cng s tng ln. Hai yu t ny u

c nh hng xu ti yu cu cht lng dch vi vi lu lng thi gian

thc.

- Phng n khc l s dng IP song hin nay IPv4 c mt s cc nhc im

nghim trng v gii hn khng gian a ch v khng p ng QoS. Ngc

li th ATM v cc lp tc bit tng ng ca n li p ng rt tt ccyu cu v QoS. C mt gii php l ATM v IP c kt hp cho cc lu

lng gi, trong giao thc IP sc s dng trn nh ca ATM. Gii

php kt hp ny s kthp c u im ca c hai giao thc l IP sm

bo vic ktni cn ATM sm bo cht lng kt ni v nh tuyn. Do

nhc im ca IPv4 nn gii php tho hip l trong mng 3G mt s phn

t mng nht nh s dng cc a ch IPv4 cnh, cn cc lu lng thu

bao cn li s dng cc a ch IPv6 c phn bng. Trong trng hp

ny, thch ng mng 3G vi cc mng khc, mng li IP 3G phi c thit

b chuyn i gia cc a ch IPv4 v IPv6 bi v cc mng khc c th

khng h tr IPv6.

Cc nt mng li cng cn phic chuyni v mt k thut. Cc phn

t chuyn mch knh cn phi x l c cho c hai loi thu bao 2,5G v 3G.

Yu cu ny i hi phi thay i trong MSC/VLR v HLR/AC/EIR. V d, c

ch bo mt trong khi thit lp cuc gi l hon ton khc nhau trong mng 2,5G

v 3G v nh vy cc phn t chuyn mch knh phi c nng cp x l

cho c hai trng hp ny. Cc phn t chuyn mch gi thc cht sc nng


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cp t GPRS. Trong trng hp ny, v tn vn gi nguyn nh trong mng

2,5G song chc nng s c nhng khc bit. Thay i ln nht i vi cc SGSN

l chc nng ca n gn nh hon ton khc vi trong mng 2,5G. Trong mng2,5G, chc nng chnh ca cc SGSN l qun l di ng cho cc kt ni gi.

Sang mng 3G, chc nng qun l di ng c phn chia gia RNC v SGSN.

iu ny c ngha l khi thu bao trong mng 3G chuyn cell th cc phn t

chuyn mch gi khng nht thit can thip, song RNC th phi qun l qu trnh

ny.

Mng 3G trin khai theo 3GPP R99 cung cp cc loidch v ging vi mng2,5G. Trong giai on ny hu ht cc dch vc chuyni sang dng gi

khi ng dng c yu cu. WAP l mt trong cc ng c vin thuc loi ny, bi

v v bn cht thng tin truyni th WAP l loi chuyn mch gi. Cc dch v

chuyn mch gi chia lm cc nhnh dch v, trong mi nhnh sgm nhiu

loi dch v khc nhau v l cc dch v trn cscch nh v v tr thu bao

sn c trong mng 3G.

Bc pht trin tip sau 3GPP R99 hin nay cn cha t mc c th m

chc xc nh cc xu hng chung. Cc xu hng chnh l vic tch bit

phn kt ni cuc gi, phn iu khin v phn dch v, ng thi yu cu

chuyni mng theo hng hon ton trn csIP. Trn quan im pht trin

dch v, cc bc pht trin ny phi lm cho mng 3G c th cung cp tt cc

dch va phng tin, v d cc dch v kt hp ng thi thoi v hnh nh.


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4.3.1.2. Phng n 3G theo chun 3GPP R4

Qun l mng (NMS)

Um

MS

BTS

GERAN

BSC

Iu CN CS DomainMSC Server

MGW MGWISDN

PSTNCSPDN

UE UTRAN

BS RNCSGSN GGSN

IMS IP, Multimedia

Uu CN PS Domain

Ghi ch:IMS = IP Multimedia Subsystem HSS V

AS

C W M UA A E SM P X AE E TL

Hnh 4.3 Mng 3G theo chun 3GPP R4

Trong giai on 3GPP R4 mi ch trin khai vic tch bit phn kt ni

cuc gi, phniu khin v phn dch v cho phn mng li chuyn mch knh.

Trong mng li ny, lu lng d liu thu bao s i qua MGW (Media

Gateways) l phn m bo kt ni v cc chc nng chuyn mch khi c yu

cu. Ton b qu trnh ny c qun l bi mt MSC Server c nng cp t

MSC/VLR. Mt MSC server c thiu khin nhiu MGW v do vy mng li

chuyn mch knh c th mrng d dng. Khi nh khai thc mun tng thmphn dung lng cho iu khin th c th thit lp thm mt MSC server, ngc

li khi mun tng dung lng chuyn mch th thit lp thm cc MGW.

Khi thit lp mt mng nh trn th cc bc pht trin v cng ngh v yu


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cu ch tiu k thut s xc nh gii hn tip theo ca mng ny. Khi IPv6 cng

c trin khai nhiu trn mng 3G th s kt ni ca mng 3G c th chuyn

i sang IPv6 cng tng v do vy s lm gim yu cu chuyni gia IPv4 vIPv6. Trong giai on ny, t trng lu lng gia d liu chuyn mch knh v

chuyn mch gi s thay i ng k. Hu ht lu lng s l chuyn mch gi,

v mt sdch v chuyn mch knh truyn thng v d nh thoi t nht s mt

phn trthnh gi (VoIP, Voice over IP). V d mt cuc gi GSM truyn thng

c thay bng mt cuc gi VoIP qua MGW m BSS ktni ti. Trn thc t

c nhiu cch trin khai cc cuc gi VoIP song ngi ta s thm vo mtphn h mng li mi c tn l IMS (IP Multimedia Subsystem) bi v n s

cung cp cc phng php thng nht x l cuc gi VoIP. Ngoi ra, IMS

cn ng thi c s dng cho cc dch v a phng tin trn c s IP.

ng nhin phn h BSS cng phi c trin khai nng cp s dng IP

song thi im cn cha xc nh. Trong trng hp ny, vai tr ca CAMEL

cng s thay i. Bi v rt nhiu dch v s dng CAMEL c chuyn t phn

mng chuyn mch knh sang chuyn mch gi nn giai on ny, CAMEL

phi c thit lp kt ni vi phn mng chuyn mch gi, ng thi l phn t

kt ni gia phn dch v v mng.

4.3.1.3. Phng n 3G theo chun: 3GPP R5


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Qun l mng (NMS) ISDNUm

PSTN

CSPDN

MS

BTS

GERAN

BSC

Iu

SGSN GGSN IMSIP, Multimedia

IP/ATM

UE UTRAN

IP/ATMCN PS Domain

C W M U

BS

IP/ATM

Uu

RNC HSSV

AS

A A E SM P X AE E T

L

Ghi ch: IMS = IP Multimedia Subsystem

Hnh 4.4 Mng 3G theo chun 3GPP R5 (ton IP)

Trong 3GPP R5, cng ngh s tip tc chuyn i v ton b cc lu

lng trong mng 3G s l lu lng IP. Ly v d mt cuc gi t thit bu

cui ca mng ti mng PSTN th n phi chuyn qua mng 3G theo dng gi v

t GGSN cuc gi VoIP sc nh tuyn qua IMS c cc chc nng chuyn

i ti PSTN.

Trn quan im ca u cui di ng th mng lun lun ging nhau trong

cc giai on pht trin. Tuy nhin, trong ni b mng th hu nh mi th thay

i. Thay i chnh trc ht l cng ngh truyn ti m trong trin khai 3GPP

R99 l ATM v sau ny 3GPP R4 v R5 chuyn sang IP. Bi v h thng cn

phi tng thch ngc nn nh khai thc lun c mt la chn l sdng cng

ngh truyn ti ATM hoc IP, hoc l c gii php cho c hai cng ngh ny.Nh gii thch trc y, ATM c th mnh l h tr QoS ngay tu, sau

cng ngh IP s c cch bo m QoS trin khai cho khng ch cho ATM m

cn cho nhiu loi phn h mng khc nhau.


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Sang giai on ny, dch v v mng trnn quan trng hn l bn thn cng

ngh, v do vy loi cng ngh truy nhp v tuync sdng s gim ngha

quan trng ca mnh. Tiu chun la chn loi cng ngh truy nhp v tuyns dng l kh nng cung cp bng thng cho cc dch v yu cu. Trong

tng lai, cc mng li 3G s c cc giao din cho mt vi cng ngh truy nhp

v tuyn, v d nh GSM, EDGE, cdma-2000, W-CDMA v WLAN. ng

nhin n st ra nhiu yu cu cho cc nh ch to thit bu cui v yu cu

th trng s phi c cc u cui x l c nhiu loi cng ngh truy nhp v

tuyn. u cui 3G dn dn s trthnh vt bt ly thn vi nhiu chc nng nhmt in thoi, v, card ID v h chiu, .v.v.

4.3.2 La chn phng n cng ngh v gii php mng

Viettel s la chn cng ngh WCDMA (hay l UMTS) v mt s cc tiu

ch trong:

UMTS l s pht trin ln 3G ca h cng ngh GSM (GSM, GPRS &

EDGE), l cng ngh duy nht c cc nc chu u cng nhn cho mng 3G.

GSM v UMTS cng l dng cng ngh chim th phn ln nht trn th trng

thng tin di ng ngy nay (chimti 85,4% theo GSA 8-2007).

UMTS hon ton tng thch ngc vi GSM. Cc my handset UMTS

thng h trc hai ch GSM v UMTS do vy chng c th s dng vi cc

mng GSM hin c. Nu mt thu bao UMTS ra khi vng ph sng ca mng

UMTS v i vo vng ph sng GSM th cuc gi ca thu bao c t ng

chuyn giao cho mng GSM.

Nh vy: WCDMA l cng ngh duy nht hin nay c thit b sn

sng, c nhiu nh cung cp thit b sn xut v c th cung cp ngay khi c

n t hng. Mt khc, do quy m th trng ln v l cng ngh trng


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thnh nn WCDMA cng l mt trong nhng cng ngh c chi phu t thp

nht, em li hiu qu cao nht.

Mng di ng hin ti Viettel hin ti l GSM v c trin khaiGPRS. tn dng c mng li 2,5 G cng nhcsh tng vn c th cng

ngh la chn l WCDMA. Ngoi ra, WCDMA c mng bo hiu pht trin t

giao thc GSM MAP nn s thun tin cho vic tng thch ngc vi mng

GSM.

71037393-wcdmanangcapgsmlen3g

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