Cong Nghe Va Qui Hoach Mang W-CDMA

8/2/2019 Cong Nghe Va Qui Hoach Mang W-CDMA

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MC LCCc t vit tt .................... ......................... ......................... .................................. 4M u .................................................................................................................11Chng 1 TNG QUAN V THNG TINDI NG S.1.1. Gii thiu ..................... ......................... ......................... ............................131.2. H thng thng tin di dng th h 1 ..................... ........................................141.3. H thng thng tin di dng th h 2 ..................... ........................................151.3.1 a truy cp phn chia theo thi gian TDMA........................................151.3.2 a truy cp phn chia theo m CDMA....................................... .........11.4 H thng thng tin di ng th h ba.............................................................17

1.5 Kt lun chng ....................................... ....................................................18Chng 2 GII THIU H THNG THNG TIN DI NGGSM.2.1. Gii thiu lch s pht trin ..................... .....................................................192.2. Cu trc mng GSM.................... ......................... ........................................202.2.1. Trm di ng ......................................... ....................................................212.2.2. H thng con trm gc................................................... ............................222.2.3. H thng mng con....... ......................... ....................................................22

2.2.4 a truy cp trong GSM............. ......................... ........................................232.2.5 Cc th tc thng tin..................................................................................242.2.5.1 ng nhp thit b vo mng........................... ........................................242.2.5.2 Chuyn vng....................................... ....................................................252.2.5.3 Thc hin cuc gi ......................................... ........................................252.2.5.3.1 Cuc gi t thit b di ng vo in thoi c nh.............................2.2.5.3.2 Cuc gi t in thoi c nh n thit b di ng............................ .

2.2.5.3.3 Cuc gi t thit b di ng n thit b di ng.................................. .2.2.5.3.4 Kt thc cuc gi. ..................... ......................... ..................................272.3 S pht trin mng GSM ln 3G..................................................................282.3.1 H thng GSM s c nng cp tng bc ln th h ba..........................282.3.2 Cc gii php nng cp ......................... ....................................................28


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2.4 Kt lun chng. ....................................... ....................................................30Chng 3 CNG NGH DI NG TH HBA W-CDMA.3.1 . Gii thiu cng ngh W-CDMA....................................................................323.2 . Cu trc mng W-CDMA ......................... ........................ ............................343.2.1 Mng truy nhp v tuyn ....................... ......................... ...........................363.2.1.1 c trng ca UTRAN ....................... ......................... ...........................373.2.1.2 B iu khin mng v tuyn UTRAN ....................... ......................... ...3.2.1.3 Node B ........................................ ......................... ......................... .........33.2.2 Giao din v tuyn.....................................................................................33.2.2.1. Giao din UTRAN CN, IU ..................................................................39

3.2.2.2. Giao din RNC RNC, IUr ......................................................................40 3.2.2.3. Giao din RNC Node B, IUb .................................................................413.3 Kt lun chng ......................... ......................... ........................................41Chng 4 CC GII PHP K THUT TRONG W-CDMA.4.1 Gii thiu ......................................................................................................434.2 M ha ..........................................................................................................434.2.1 M vng ....................... ......................... ......................... ............................43

4.2.2 M xon ..................... ......................... ....................................................454.2.3. M Turbo....................................................................................................454.3 iu ch BIT/SK v QPSK................................... ........................................454.3.1 iu ch BIT/SK........................................................................................454.3.2 iu ch QPSK...........................................................................................454.4 Tri ph trong W-CDMA ............................................ ......................... .........44.4.1 Gii thiu....................................................................................................4

4.4.2 Nguyn l tri ph DSSS............................................................................5

4.4.3 M tri ph ................... ......................... ............................................ .........54.4.4 Cc hm trc giao.......................................................................................534.5 Cu trc phn knh ca WCDMA ......................... ........................................534.5.1 Knh vt l ................... ......................... ......................... ............................54


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4.5.1.1 Knh vt l ring ng ln................. ......................... ............................544.5.1.2 Knh vt l chung ng ln ......................................... ...........................564.5.1.3 Knh vt l ring ng xung (DPCH)....................... ............................604.5.1.4 Knh vt l chung ng xung ....................... ........................................604.5.2. Knh truyn ti ....................................... .....................................................654.5.2.1 Knh truyn ti ring ..................... ......................... ..................................654.5.2.2. Knh truyn ti chung...............................................................................4.5.2.3 Sp xp knh truyn ti ln knh vt l ......................... ......................... ..4.6 Truy nhp gi trong W-CDMA......................................................................64.6.1 Tng quan v truy nhp gi trong W-CDMA.............................................68

4.6.2. Lu lng s liu gi..................................................... ...........................684.6.3 Cc phng php lp biu gi....................................................................694.6.3.1 Lp biu phn chia theo thi gian................................ ............................694.6.3.2. Lp biu phn chia theo m.....................................................................704.7. Kt lun chng ...........................................................................................70Chng 5 QUY HOCH MNG W-CDMA.5.1 Gii thiu.......................................................................................................71

5.2 Tnh suy hao ng truyn cho php.................................. ............................725.3. Xc nh kch thc ......................... ......................... ..................................735.3.1. M hnh Hata Okumura ......................................... ..................................735.3.2. M hnh Walfsch Ikegami........................................................................745.4. Tnh ton dung lng v vng ph ......................... ........................................765.5 Chng trnh m phng v tnh ton............................. ......................... .........75.5.1 Lu tnh ton. ........................ ......................... ......................... ...............7

5.5.2 Kt qu chng trnh. ....................... ......................... ......................... .........5.6. Kt lun chng. .................... .......................................................................82Kt lun.................................................................................................................83Ti liu tham kho.................................................................................................84Ph lc .................................................................................................................85


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Cc t vit tt

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B B n n g g t t r r a a c c u u t t v v i i t t t t t t ACCH Associated Control Channels

Knh iu khin lin kt.AI Acquisition Indicator Ch th bt.

AMPS Advanced Mobile Phone SystemH thng in thoi di ng tin tin.

ARQ Automatic Repeat RequestYu cu lp li t ng.

AS Access StratumTng truy nhp.

BCCH Broadcast Control ChannelKnh qung b iu khin.

BCH Broadcast ChannelKnh qung b.

BER Bit Error RatioT s bit li.

BSC Base Station Controler B iu khin trm gc.

BSS Base Station SubsystemPhn h trm gc.

BTS Base Tranceiver StationTrm v tuyn thu pht gc.

BPSK Binary Phase Shift Keying

Kha dch pha nh phn.CCCH Common Control Channel

Knh iu khin chung.CDMA Code Division Multiple Access

a truy cp chia theo m.


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C/I Carrier to Interference ratioT s sng mang trn nhiu.

CCCH Common Control ChanelKnh iu khin chung.

CCPCH Common Control Physical ChanelKnh vt l iu khin chung.

CPCC Common Power Control ChanelKnh iu khin cng sut chung.

CPCH Common Packet Chanel.Knh gi chung.

CPICH Common Pilot ChanelKnh hoa tiu chung.

CR Chip RateTc chip (tng ng vi tc tri ph ca knh).

CS Circuit SwitchChuyn mch knh.

DCA Dynamic Chanel Allocation

Phn b knh ng.DCCH Dedicated Control Channel

Knh iu khin dnh ring.DPCCH Dedicated Physical Control Chanel

Knh iu khin vt l ring.DPCH Dedicated Physical Chanel

Knh vt l ring.

DPDCH Dedicated Physical Data ChanelKnh s liu vt l ring.

DTCH Dedicated Traffic ChanelKnh lu lng ring.

DTE Data Terminal Equipment


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Thit b u cui s liu.DSCH Downlink Shared Chanel

Knh dng chung ng xung.EDGE Enhanced Data rate for GSM Evolution.

Tng tc truyn dnETSI European Telecommunications Standards Institute

Vin Tiu chun vin thng chu u.FACCH Fast Associated Control Channel

Knh iu khin lin kt nhanh.FACH Forward Access Chanel

Knh truy nhp ng xung.FAUSCH Fast Uplink Signalling Chanel

Knh bo hiu ng ln nhanh.FCCCH Forward Common Control Chanel

Knh iu khin chung ng xung.FCCH Frequency Correction Channel

Knh hiu chnh tn s.

FDD Frequency Division DuplexGhp knh song cng phn chia theo tn s.

FDMA Frequence Division Multiple Accessa truy cp phn chia theo tn s

FDCCH Forward Dedicated Control ChanelKnh iu khin ring ng xung.

FSK Frequency Shift Keying

Kho iu ch dch tn.GOS Grade Of Service

Cp phc v.GSM Global System for Mobile Communication

Thng tin di ng ton cu


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GPS Global Position SystemH thng nh v ton cu.

GPRS General Packet Radio ServicesDch v v tuyn gi chung.

Handover Chuyn giao.HH Hard Handoff

Chuyn giao cng.HSCSD Hight Speed Circuit Switched Data

H thng chuyn mch knh tc cao.IMT-2000 International Mobile Telecommunication

Tiu chun thng tin di ng ton cu.IMSI International Mobile Subscriber Identity

S nhn dng thu bao di ng quc t.IP Internet Protocol

Giao thc Internet.IS-54 Interim Standard 54

Tiu chun thng tin di ng TDMA ca M (do AT&T xut).

IS-136 Interim Standard 136Tiu chun thng tin di ng TDMA ci tin ca M (AT&T).

IS-95A Interim Standard 95ATiu chun thng tin di ng TDMA ci tin ca M (Qualcomm)

ISDN Integrated Servive Digital Network Mng s a dch v.

ITU-R International Mobile Telecommunication Union Radio Sector

Lin minh vin thng quc t - b phn v tuyn.IWF InterWorking Function

Chc nng tng tc mngLAC Link Access Control

iu khin truy nhp lin kt.


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LAI Location Area Indentify Nhn dng vng v tr.

LLC Logical Link Controliu khin lin kt logic.

LR Location Registrationng k v tr.

ME Mobile EquipmentThit b di ng.

MS Mobile StationTrm di ng.

MTP Message Transfer PartPhn truyn bn tin.

MSC Mobile Service Switching Center Tng i di ng.

NAS Non-Access StratumTng khng truy nhp.

Node B L nt logic kt cui giao din IuB vi RNC.

NSS Network and Switching SubsystemH thng chuyn mch

ODMA Opportunity Driven Multiplex Accessa truy cp theo c hi.

OM Operation and ManagementKhai thc v bo dng.

PAGCH Paging and Access

Knh chp nhn truy cp v nhn tin.PCCC Parallel Concatenated Convolutional Code

M xon mc ni song song.PCCH Paging Contrlo Chanel

Knh iu khin tm gi.


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PCH Paging ChannelKnh nhn tin.

PCPCH Physical Common Packet ChanelKnh gi chung vt l.

PCS Personal Communication ServicesDch v thng tin c nhn.

PLMN Public Land Mobile Network Mng di ng mt t cng cng.

PSTN Public Switched Telephone Network Mng chuyn mch thoi cng cng.

BPSK Binary Phase Shift Keying

RACH Random Access ChannelKnh truy cp ngu nhin.

RRC Radio Resource Controliu khin ti nguyn v tuyn.

SCH Synchronization Channel

Knh ng b.SDCCH Stand alone Dedicated Control Channel

Knh iu khin dnh ring.SDMA Space Division Multiple Access

a truy cp phn chia theo khng gianTACH Traffic and Associated Channel

Lnh lu lng v lin kt.

TCH Traffic ChannelKnh lu lng.

TDMA Time Division Multiple Accessa truy cp phn chia theo thi gian

TDD Time Division Duplex


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Ghp song cng phn chia thi gian.UTRAN Universal Terrestrial Radio Access Network

Mng truy nhp v tuyn mt t ton cu.UMTS Universal Mobile Telecommunnication SystemVA Voice Activity factor

H s tch cc thoi.VBR Variable Bit Rate

Tc kh bin.WCDMA Wideband Code Division Multiplex Access

a truy cp phn chia theo m bng rng.


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L L ii nnii uu ----------@----------

Thng tin di ng s ang ngy cng pht trin mnh m trn th gii

vi nhng ng dng rng ri trong cc lnh vc thng tin, trong dch v v trong cuc sng hng ngy. Cc k thut khng ngng c hon thin p ng nhu cca ngi tiu dng. Cng ngh in thoi di ng ph bin nht th gii GSM ang gp nhiu cn tr v s sm b thay th bng nhng cng ngh tin tin hh tr ti a cc dch v nh Internet, truyn hnh...

H thng vin thng di ng th h hai l GSM v IS 95. Nhng cng ngh ny ban u c thit k truyn ti ging ni v nhn tin. tn dn

c tnh nng ca h thng 2G khi chuyn hng sang 3G cn thit c mt gi php trung chuyn. Cc nh khai thc mng GSM c th bt u chuyn t GSM sang 3G bng cch nng cp h thng mng ln GPRS (Dch v v tuyn chuynmch gi), tip theo l EDGE (tiu chun 3G trn bng tn GSM v h tr d liln ti 384kbit) v UMTS (cng ngh bng thng hp GSM s dng truyn dnCDMA), v WCDMA.

3G l mt bc t ph ca ngnh di ng, bi v n cung cp bng thng rng hn cho ngi s dng. iu c ngha s c cc dch v mi vnhiu thun tin hn trong dch v thoi v s dng cc ng dng d liu nh truyn thng hu ch nh in thoi truyn hnh, nh v v tm kim thng tin, trucp Internet, truyn ti d liu dung lng ln, nghe nhc v xem video cht lcao, Truyn thng di ng ngy nay v ang ng mt vai tr quan trng trong cuc sng. Vic vn c th gi lin lc vi mi ngi trong khi di chuyn lm thay i cuc sng ring t v cng vic ca chng ta.

Th gii ang c 2 h thng 3G c chun ha song song tn ti, mda trn cng ngh CDMA cn gi l CDMA 2000, chun cn li do d n 3rGeneration Partnership Project (3GPP) thc hin. 3GPP ang xem xt tiu chunUTRA - UMTS Terrestrial Radio Access TS. Tiu chun ny c 2 s truy nhp tuyn. Mt trong s c gi l CDMA bng thng rng (WCDMA).


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Ngy 10/3/2005, B BCVT tin hnh nghim thu ti xy dng tichun thit b u cui thng tin di ng WCDMA (UTRA-FDD) m s 49- KTKT-TC dnh cho cng ngh 3G. Theo nh gi ca cc thnh vin phn bivic xy dng v hon thnh cng trnh l mt vic lm cn thit, c ngha v bit l kh thi trong giai on hin nay, khi nhu cu pht trin ln 3G l mt hng tt yu Vit Nam, nht l cc nh di ng mng GSM (Theo bo inVietNamNet).

Xut pht t tng mun tm hiu cng ngh W-CDMA v mng CDMA em thc hin n: Cng ngh W-CDMA v qui hoch mng WCDMA.

n ny em trnh by 5 chng, vi ni dung chnh l chng3, chng chng 5, gm c :

Chng 1 : Tng quan v thng tin di ng,Chng 2 : Gii thiu h thng thng tin di ng GSM,Chng 3 : Cng ngh di ng th h ba W-CDMA,Chng 4 : Cc gii php k thut trong W-CDMA,

Chng 5 : Quy hoch mng W-CDMA.Trong qu trnh lm n kh trnh khi sai st, em rt mong s ch dn

ca cc thy c gio v s gp ca cc bn n c hon thin hn.

Em xin chn thnh cm n thy H Vit Vit v cc thy c gio gip emhon thnh n ny !.

Nng, ngy 6 thng 6 nm 2007. Ngi thc hin


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Tng quan v thng tin di ng s

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Chng 1

TNG QUAN V THNG TIN DI NG S

1.1 Gii thiu.Ra i u tin vo cui nm 1940, n nay thng tin di ng tri qu

nhiu th h.Th h khng dy th 1 l th h thng tin tng t s dng ngh a truy cp phn chia phn chia theo tn s (FDMA).Th h th 2 s dngthut s vi cng ngh a truy cp phn chia theo thi gian (TDMA) v phn chtheo m (CDMA).Th h th 3 ra i nh gi s nhy vt nhanh chng v c dlng v ng dng so vi cc th h trc , v c kh nng cung cp cc dch

a phng tin gi l th h ang c trin khai mt s quc gia trn th giQu trnh pht trin ca cc h thng thng tin di ng trn th gii c

hin s pht trin ca h thng in thoi t ong (CMTS : Cellular MobTelephone System) v nhn tin (PS : Paging System) tin ti mt h thng chuton cu trong tng lai.

Hnh 1.1 th hin mt mng in thoi di ng t ong bao gm cc trm gc(B

Hnh 1.1: H thng in thoi di ng


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1.2. H thng thng tin di dng th h 1

Phng php n gin nht v truy nhp knh l a truy nhp phn chia

s . H thng di ng th h 1 s dng phng php a truy cp phn chia theos (FDMA) v ch h tr cc dch v thoi tng t v s dng k thut iutng t mang d liu thoi ca mi ngi s dng .Vi FDMA , khch hc cp pht mt knh trong tp hp c trt t cc knh trong lnh vc tn s bo hiu ca h thng FDMA kh phc tp, khi MS bt ngun hot nn d sng tm n knh iu khin dnh ring cho n. Nh knh ny, MS nhc d liu bo hiu gm cc lnh v knh tn s dnh ring cho lu lng ndng . Trong trng hp nu s thu bao nhiu hn so vi cc knh tn s c th mt s ngi b chn li khng c truy cp.

a truy nhp phn chia theo tn s ngha l nhiu khch hng c th s dc di tn gn cho h m khng b trng nh vic chia ph tn ra thnh nhon .Ph tn s quy nh cho lin lc di dng c chia thnh 2N di tn stip, v c cch nhau bng mt di tn phng v. Mi di tn s c gnmt knh lin lc. N di k tip dnh cho lin lc hng ln, sau mt di phn cch l N di k tip dnh ring cho lin lc hng xung .

c im :-Mi MS c cp pht i knh lin lc sut thi gian thng tuyn .-Nhiu giao thoa do tn s cc knh ln cn nhau l ng k .-BTS phi c b thu pht ring lm vic vi mi MS .

H thng FDMA in hnh l h thng in thoi di dng tin ti(Advanced Mobile phone System - AMPS).

H thng thng tin di ng th h 1 s dng phng php a truy cn gin. Tuy nhin h thng khng tho mn nhu cu ngy cng tng cngi dng v c dung lng v tc . V cc khuyt im trn m ngua ra h thng thng tin di dng th h 2 u im hn th h 1 v c lng v cc dch v c cung cp.


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1.3 . H thng thng tin di dng th h 2

Cng vi s pht trin nhanh chng ca thu bao c v s lng v ch

lng, h thng thng tin di ng th h 2 c a ra p ng kp thlng ln cc thu bao di ng da trn cng ngh s .

Tt c h thng thng tin di ng th h 2 s dng iu ch s .V chs dng 2 phng php a truy cp :

a truy cp phn chia theo thi gian (Time Division Multiple Access -TDMA).

a truy cp phn chia theo m (Code Division Multiple Access -CDMA).

1.3.1 a truy cp phn chia theo thi gian TDMA.Vi phng php truy cp TDMA th nhiu ngi s dng mt sng mang

trc thi gian c chia thnh nhiu khong thi gian nh dnh cho nhiu ngs dng sao cho khng c s chng cho. Ph quy nh cho lin lc di ngc chia thnh cc di tn lin lc, mi di tn lin lc ny dng chung N knh lin lc, mi knh lin lc l mt khe thi gian trong chu k mkhung. Cc thu bao khc dng chung knh nh ci xen thi gian, mi thu bac cp pht cho mt khe thi gian trong cu trc khung .

c im :-Tn hiu ca thu bao c truyn dn s.-Lin lc song cng mi hng thuc cc di tn lin lc khc nhau, tro

mt bng tn c s dng truyn tn hiu t trm gc n cc di ng v mt bng tn c s dng truyn tn hiu t my di ng trm gc. Vic phn chia tn nh vy cho php cc my thu v my pht c t

hot ng cng mt lc m khng s can nhiu nhau.-Gim s my thu pht BTS.-Gim nhiu giao thoa.

H thng TDMA in hnh l h thng thng tin di ng ton c(Global System for Mobile Communications - GSM).


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My in thoi di ng k thut s TDMA phc tp hn k thuFDMA. H thng x l s i vi tn hiu trong MS tng t c kh nng l khng qu 106 lnh trong 01 giy, cn trong MS s TDMA phi c khnng x l hn 50x106 lnh trn giy.

1.3.2 a truy cp phn chia theo m CDMA.Vi phng php a truy cp CDMA s dng k thut tri ph cho n

nhiu ngi s dng c th chim cng knh v tuyn ng thi tin hcc cuc gi m khng s gy nhiu ln nhau. Nhng ngi s dng ntrn c phn bit vi nhau nh dng mt m c trng khng trng v bt k ai. Knh v tuyn CDMA c dng li mi cell trong ton mng, nhng knh ny cng c phn bit nhau nh m tri ph gi ngu nhi(Pseudo Noise - PN).

c im ca CDMA:-Di tn tn hiu rng hng MHz.-S dng k thut tri ph phc tp.-K thut tri ph cho php tn hiu v tuyn s dng c cng

trng rt nh v chng fading hiu qu hn FDMA, TDMA..

-Vic cc thu bao MS trong cell dng chung tn s khin cho thit btruyn dn v tuyn n gin, vic thay i k hoch tn s khng cn , chuyn giao tr thnh mm, iu khin dung lng cell rt linh hot.

1.4 H thng thng tin di ng th h ba.

Cng ngh thng tin di ng s th h ba. Cng ngh ny lin quan n nhci tin ang c thc hin trong lnh vc truyn thng khng dy cho in thv d liu thng qua bt k chun no trong nhng chun hin nay. u tintng tc bit truyn t 9.5Kbps ln 2Mbps. Khi s lng thit b cm tay thit k truy cp Internet gia tng, yu cu t ra l phi c c cng ntruyn thng khng dy nhanh hn v cht lng hn. Cng ngh ny s nng ccht lng thoi, v dch v d liu s h tr vic gi ni dung video v multim


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n cc thit b cm tay v in thoi di ng.

Cc h thng thng tin di ng s hin nay ang giai on chuyn t th

2.5G sang th h 3 (3 - Generation). p ng nhu cu ngy cng tng v cc dv thng tin di ng, ngay t u nhng nm u ca thp k 90 ngi ta hnh nghin cu hoch nh h thng thng tin di ng th h ba. ITU-R ang thnh cng tc tiu chun ha cho h thng thng tin di ng ton cu IMT-2000. chu u ETSI ang tin hnh tiu chun ha phin bn ny vi tn gi l UMT(Universal Mobile Telecommunnication System). H thng mi ny s lm vicdi tn 2GHz. N s cung cp nhiu loi hnh dch v bao gm cc dch v thos liu tc cao, video v truyn thanh. Tc cc i ca ngi s dng cln n 2Mbps. Ngi ta cng ang tin hnh nghin cu cc h thng v tuynh th t c tc ln n 32Mbps.

H thng thng tin di ng th h ba c xy dng trn c s IMT 20vi cc tiu ch sau :

- S dng di tn quy nh quc t 2GHz vi ng ln c di tn 182025MHz v ng xung c di tn 2110-2200MHz.

- L h thng thng tin di ng ton cu cho cc loi hnh thng tin v tuytch hp cc mng thng tin hu tuyn v v tuyn, ng thi tng tc vi mloi dch v vin thng.

- H thng thng tin di ng 3G s dng cc mi trng khai thc khc nhau- C th h tr cc dch v nh : Mi trng thng tin nh o (VHE Vitu

Home Environment) trn c s mng thng minh, di ng c nhn v chuyn mton cu; m bo chuyn mng quc t; m bo cc dch v a phng tinthi cho thoi, s liu chuyn mch theo knh v s liu chuyn mch theo gi.

- D dng h tr cc dich v mi xut hin.Cc h thng thng tin di ng th h hai pht trin thng dng nht hin

l : GSM, cdmaOne (IS-95), TDMA (IS-136), PDC. Trong qu trnh thit k hthng thng tin di ng th h ba, cc h thng th h hai c c quan chunca tng vng xem xt a ra cc xut tng ng thch hp vi mi vng.


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1.5 Kt lun chng

Chng ny gii thiu tng quan v qu trnh pht trin ca h thng th

tin di ng. Vi nhu cu khng ngng tng ln ca ngi s dng c v cht lv s lng, nhu cu trao i thng tin trnh cao v a dng s pht trin tt yu.Hin nay cng ngh 3G ang c ng dng mt cch mnh m cc ntrn th gii vi cc dch v tin ch nh in thoi truyn hnh, truy nhp inte


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Chng 2

GII THIU H THNG THNG TIN DI NG GSM

2.1 Gii thiu chng.

Chng ny s gii thiu v s hnh thnh v pht trin ca h thng thngdi ng GSM, kin trc mng GSM , phng php a truy cp trong GSM , cc ttc thng tin ca thu bao s dng trong mng v s cn thit phi nng cp mGSM ln th h 3G.

Lch s hnh thnh GSM bt u t mt xut vo nm 1982 ca NordTelecom v Netherlands ti CEPT (Conference of European Post andTelecommunication) pht trin mt chun t bo s mi p ng vi nhu ngy cng tng ca mng di ng Chu u.

y ban Chu u (EC) a ra li hng dn yu cu cc quc gia thnh vis dng GSM cho php lin lc di ng trong bng tn 900MHz. Vin tiu chuvin thng Chu u (ETSI) nh ngha GSM khi quc t chp nhn tiu chun thng in thoi t bo s.

Li xut c kt qu vo thng 9 nm 1987, khi 13 nh iu hnh v qunca nhm c vn CEPT GSM tha thun k hip nh GSM MoU Club, vi ngkhi u l 1 thng 7 nm 1991.

GSM l t vit tt ca Global System for Mobile Communications (h thnthng tin di ng ton cu), trc y c tn l Groupe Spcial Mobile.

H thng thng tin di ng ton cu GSM l h thng thng tin t bo s thp v ton din, c pht trin u tin Chu u v nhanh chng pht tr

trn ton th gii. Mng c thit k ph hp vi h thng ISDN v cc dchm GSM cung cp l mt h thng con ca dch v ISDN chun.


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Hnh 2.1

GSM u tin c thit k hot ng di tn 890-915 MHz v 935-9MHz, hin nay l 1.8GHz. Mt vi tiu chun chnh c ngh cho h thng

Cht lng m thoi chnh thc s tt. Gi dch v v thu bao gim. H tr lin lc di ng quc t. Kh nng h tr thit b u cui trao tay. H tr cc phng tin thun li v dch v mi. Nng sut quang ph. Kh nng tng thch ISDN.

Tiu chun c ban hnh vo thng ging nm 1990 v nhng h thnthng mi u tin c khi u vo gia nm 1992. T chc Mo(Memorandum of Understanding) thnh lp bi nh iu hnh v qun l GSc cp php u tin, lc c 13 hip nh c k kt v n nay c thnh vin khp th gii. T chc MoU c quyn lc ti a, c quyn chun GSM.

2.2. Cu trc mng GSM

Mng GSM gm nhiu khi chc nng khc nhau. Hnh di cho thy c b tr ca mng GSM tng qut. Mng GSM c th chia thnh ba phn chTrm di ng (Mobile Station_MS) do thu bao gi. H thng con trm gc (B Station Subsystem_BSS) iu khin lin kt vi trm di ng. H thng mng(Network Subsystem_NS) l phn chnh ca trung tm chuyn mch dch v


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ng MSC (Mobile services Switching Center), thc hin chuyn mch cuc ggia nhng ngi s dng in thoi di ng, v gia di ng vi thu bao mnnh. MSC x l cc hot ng qun l di ng. Trong hnh khng c trnh btrung tm duy tr v iu hnh (Operations and Maintenance Center_OMS), gimst iu hnh v c cu ca mng. Trm di ng v h thng con trm gc thtin dng giao tip Um, cn c gi l giao tip khng trung hay lin kt v tuyH thng con trm gc lin lc vi trung tm chuyn mch dch v di ng dgiao tip A.

Hnh 2.2 :M hnh h thng thng tin di ng t bo

2.2.1 Trm di ng

Trm di ng (Mobile Station_MS) gm c thit b di ng (u cui) v mcard thng minh gi l module nhn dng thu bao (Subscriber IdentityModule_SIM). SIM cung cp thng tin c nhn di ng, v th ngi s dng tr

cp vo cc dch v thu bao khng ph thuc vo loi thit b u cui. Bng gn SIM vo u cui GSM, ngi s dng c th nhn, gi v nhn cc dchthu bao khc trn thit b u cui ny.


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Thit b di ng c nhn dng duy nht bng s nhn dng thit b di quc t (International Mobile Equipment Identity_IMEI). SIM card cha s nhdng thu bao di ng quc t (International Mobile Subscriber Identity_IMSI) sdng nhn dng thu bao trong h thng, dng xc nh ch quyn v thtin khc. S IMEI v IMSI c lp nhau. SIM card c th c bo v chngvic s dng tri php bng password hoc s nhn dng c nhn.

2.2.2. H thng con trm gc.

H thng con trm gc gm hai phn:trm gc thu pht (BTS)v trm gciu khin (BSC). Hai h thng ny lin kt dng giao tip Abis chun ho, ch

php iu hnh cc b phn cung cp bi cc nh sn xut khc nhau.Trm thu pht gc l ni my thu pht v tuyn ph mt cell v iu khin

giao thc lin kt v tuyn vi trm di ng. Trong mt thnh ph ln, c nhkh nng trin khai nhiu BTS, do yu cu BTS phi chnh xc, tin cy, chuyn c v gi thnh thp.

Trm gc iu khin ti nguyn v tuyn ca mt hoc nhiu BTS. Trm khin cch thit lp knh truyn v tuyn, nhy tn v trao tay.BSC l kt ni

gia trm di ng v tng i di ng (MSC).

2.2.3. H thng mng con.

Thnh phn chnh ca h thng mng con l tng i di ng, hot ng nmt nt chuyn mch bnh thng ca PSTN hoc ISDN, v cung cp tt cchc nng cn c iu khin mt thu bao di ng, nh ng k, xc nhn, nht ta , trao tay, v nh tuyn cuc gi cho mt thu bao lin lc di Nhng dch v ny c cung cp chung vi nhiu b phn chc nng khc,nn h thng mng con. MSC cung cp kt ni n mng c nh (nh PSTN ISDN). Bo hiu gia cc b phn chc nng trong h thng mng con l h th bo hiu s 7 (SS7) s dng cho bo hiu trung k trong mng ISDN v m rndng trong mng cng cng hin ti.


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B ghi nh v thng tr (HLR) v b ghi nh v tm tr (VLR) cng vMSC cung cp nh tuyn cuc gi v kh nng lin lc di ng ca GSM. Hcha tt c thng tin qun tr ca mi thu bao ng k trong mng GSM tng, cng vi v tr hin ti ca di ng. V tr ca di ng thng di dnch bo hiu ca VLR cha trm di ng.

B ghi nh v tm tr (VLR) cha thng tin qun tr c chn t HLR, cthit cho iu khin cuc gi v cung cp cc dch v thu bao, cho mi thu hin ti nm trong vng a l iu khin bi VLR. Mc d mi b phn chc chung c th c thc hin c lp nhng tt c cc nh sn xut thit b chmch cho n nay u sn xut VLR vi MSC, v th vng a l iu khinMSC s tng ng vi iu khin bi VLR , do n gin ha bo hiu thit. Lu rng MSC khng cha thng tin cc trm di ng thng tin ny ltr trong cc thanh ghi v tr.

C hai b ghi khc s dng cho mc ch xc nhn v bo mt. B ghi nhthc thit b (EIR) l mt c s d liu cha mt danh sch tt c cc thit bng hp l trn mng, mi trm di ng c xc nhn bng s nhn dng thdi ng quc t (IMEI). S IMEI b nh du l khng hp l nu c thng mt cp hoc khng c chp thun. Trung tm nhn thc AuC l c s dc bo v cha bn sao kha m trong SIM card ca thu bao, s dng nthc v m ha trn knh v tuyn.

2.2.4 a truy cp trong GSM.

Mng GSM kt hp hai phng php a truy cp l FDMA v TDMA. Di t935 960MHz c s dng cho ng ln v 890 915MHz cho ng xu

(GSM 900). Di bng thng tn mt knh l 200KHz, di tn bo v bin crng 200KHz nn ta c tng s knh trong FDMA l 124. Mt di thng TDMA mt khung c tm khe thi gian, mt khung ko di trong 4.616ms. Khung nln tr 3 khe thi gian so vi khung ng xung, nh tr ny m MS c c th


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dng mt khe thi gian c cng s th t c ng ln ln ng xung trtin bn song cng.

Cc knh tn s c s dng GSM nm trong dy tn s quy nh 900Mxc nh theo cng thc sau:

FL = 890,2 + 0,2.(n-1) MHzFU = FL(n) + 45 MHz

1 n 124

T cng thc trn FL l tn s na bng thp, FU l tn s na bng cao,0,2MHz l khong cch gia cc knh ln cn, 45Mhz l khong cch thu pht, n

knh tn v tuyn. Ta thy tng s knh tn s c th t chc cho mng GSM124 knh. cho cc knh ln cn khng gy nhiu cho nhau mi BTS ph mca mng phi s dng cc tn s cch xa nhau v cc ch c s dng li t khong cch cho php.

Truyn dn v tuyn GSM c chia thnh cc cm(BURST)cha hngtrm bit c iu ch. Mi cm c pht i trong mt khe thi gian 577trong mt knh tn s c rng 200 Khz ni trn. Mi mt knh tn s cho p

t chc cc khung thm nhp theo thi gian, mi khung bao gm 8 khe thi gian 0 7 (TS0, TS1,...TS7).

2.2.5 Cc th tc thng tin.

2.2.5.1 ng nhp thit b vo mng.

Khi mt thu bao khng trng thi gi, n s qut 21 knh thit lp trn ts 416 knh. Sau n chn mt knh mnh nht v kha knh ny. Sau 60s qtrnh t nh v c lp li.

Khi thu bao bt ln, thit b d tn s GSM tm knh iu khin. Sau thit b o cng ca tn hiu t cc knh v ghi li. Cui cng chuyn sangni vi knh c tn hiu mnh nht.

2.2.5.2 Chuyn vng.


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V GSM l mt chun chung nn thu bao c th dng in thoi h GSM hu ht cc mng GSM trn th gii. Trong khi di chuyn thit b lin tc d k lun duy tr tn hiu vi trm l mnh nht. Khi tm thy trm c tn hiu mhn, thit b s t ng chuyn sang trm mi, nu trm mi nm trong vngkhc thit b s bo cho mng bit v tr mi ca mnh.

Ring trong ch chuyn vng quc t hoc chuyn vng gia mng canh khai thc dch v khc nhau th qu trnh cp nht v tr i hi phi c s chthun v h tr t cp nh khai thc dch v.

2.2.5.3 Thc hin cuc gi.

2.2.5.3.1 Cuc gi t thit b di ng vo in thoi c nh.Trnh t thit lp cuc gi t thit b di ng vo in thoi c nh nh sau

1. Thit b gi yu cu mt knh bo hiu.

2. BSC/TRC s ch nh knh bo hiu.

3. Thit b gi yu cu cuc gi cho MSC/VLR. Thao tc ng k trng thtch cc cho thit b vo VLR, xc thc, m ha, nhn dng thit b, gi s c

cho mng, kim tra xem thu bao c ng k dch v cm gi ra u c thc htrong bc ny.

4. Nu hp l MSC/VLR bo cho BSC/TRC mt knh ang ri.

5. MSC/VLR chuyn tip s c gi cho mng PSTN.

6. Nu my c gi tr li, kt ni s thit lp.


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2.2.5.3.2 Cuc gi t in thoi c nh n thit b di ng.

im khc bit quan trng so vi gi t thit b di ng l v tr ca thikhng c bit chnh xc. Chnh v th trc khi kt ni, mng phi thc hcng vic xc nh v tr ca thit b di ng.

1. T in thoi c nh, s in thoi di ng c gi n mng PSMng s phn tch v nu pht hin ra t kha gi mng di ng, mng PSTN sni vi trung tm GMSC ca nh khai thc thch hp

2. GMSC phn tch s in thoi di ng tm ra v tr ng k gc tronHLR ca thit b v cch thc ni n MSC/VLR phc v.

3. HLR phn tch s di ng gi n tm ra MSC/VLR ang phc v cthit b. Nu c ng k dch v chuyn tip cuc gi n, cuc gi s c tGMSC vi s in thoi c yu cu chuyn n.

4. HLR lin lc vi MSC/VLR ang phc v.

5. MSC/VLR gi thng ip tr li qua HLR n GMSC.

6. GMSC phn tch thng ip ri thit lp cuc gi n MSC/VLR.

7. MSC/VLR bit a ch LAI ca thit b nn gi thng ip n BSC qunLAI ny.

GSM/PLMN PSTN

1

2

3

4 4

1

2

3

4

BSC/TRC MSC/VLR Thi t bu cui

Hnh 2.3. Gi t thit b di ng vo in thoi c nh

5 6


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cc trm gc v hai bn cng gii phng cuc gi. MS tip tc kim tra tm thng qua knh thit lp mnh nht.

2.3 S pht trin ca mng GSM ln 3G

2.3.1 H thng GSM s c nng cp tng bc ln th h ba.

p ng c cc dch v mi v truyn thng a phng tin trn phmton cu ng thi m bo tnh kinh t, h thng GSM s c nng cp bc ln th h ba. Thng tin di ng th h ba c kh nng cung cp dchtruyn thng multimedia bng rng trn phm vi ton cu vi tc cao ng tcho php ngi dng s dng nhiu loi dch v a dng. Vic nng cp GSM

3G c thc hin theo cc tiu ch sau :- L mng bng rng v c kh nng truyn thng a phng tin trn phm

ton cu. Cho php hp nht nhiu chng loi h thng tng thch trn ton c

- C kh nng cung cp rng bng thng theo yu cu nhm h tr mt rng cc dch v t bn tin nhn tc thp thng qua thoi n tc d likhi truyn video hoc truyn file. m bo cc kt ni chuyn mch cho thoidch v video v kh nng chuyn mch gi cho dch v s liu. Ngoi ra n cntr ng truyn v tuyn khng i xng tng hiu sut s dng mng (chn nh tc bit cao ng xung v tc bit thp ng ln).

- Kh nng thch nghi ti a vi cc loi mng khc nhau m bo cc dv mi nh nh s c nhn ton cu v in thoi v tinh. Cc tnh nng nycho php m rng ng k vng ph sng ca cc h thng di ng.

- Tng thch vi cc h thng thng tin di ng hin c bo m s ptrin lin tc ca thng tin di ng. Tng thch vi cc dch v trong ni b IM2000 v vi cc mng vin thng c nh nh PSTN/ISDN. C cu trc m c php a vo d dng cc tin b cng ngh, cc ng dng khc nhau cng nh nng cng tn ti v lm vic vi cc h thng c.

2.3.2 Cc gii php nng cp


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C hai gii php nng cp GSM ln th h ba : mt l b hn h thng c, tth bng h thng thng tin di ng th h ba; hai l nng cp GSM ln GPRStip n l EDGE nhm tn dng c c s mng GSM v c thi gian chu tin ln h thng 3G W-CDMA. Gii php th hai l mt gii php c tnh thi v tnh kinh t cao nn y l gii php c a chung nhng nc ang ptrin nh nc ta.

Giai on u ca qu trnh nng cp mng GSM l phi m bo dch v s

tt hn, c th h tr hai ch dch v s liu l ch chuyn mch knh Circuit Switched) v ch chuyn mch gi (PS : Packet Switched). thc hkt ni vo mng IP, giai on ny c th s dng giao thc ng dng v tu(WAP : Wireless Application Protocol). WAP cha cc tiu chun h tr truy cinternet t trm di ng. H thng WAP phi c cng WAP v chc nng kt nmng.

Hnh 2.5 Cc gii php nng cp h thng 2G ln 3G


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Trong giai on tip theo, tng tc s liu c th s dng cng nghliu chuyn mch knh tc cao (HSCSD : High Speed Circuit Switched Data) dch v v tuyn gi chung (GPRS : General Packet Radio Protocol ServicesGPRS s h tr WAP c tc thu v pht s liu ln n 171.2Kbps. Mt u quan trng ca GPRS na l thu bao khng b tnh cc nh trong h thchuyn mch knh m cc ph c tnh trn c s lu lng d liu s dng v thi gian truy cp.

Dch v GPRS to ra tc cao ch yu nh vo s kt hp cc khe thi gtuy nhin k thut ny vn da vo phng thc iu ch nguyn thu GMSK hn ch tc truyn. Bc nng cp tip theo l thay i k thut iu ch kvi ghp khe thi gian ta s c tc truyn d liu cao hn, chnh l cng nEDGE.

EDGE vn da vo cng ngh chuyn mch knh v chuyn mch gi vi ti a t c l 384Kbps nn s kh khn trong vic h tr cc ng dnghi vic chuyn mch linh ng v tc truyn d liu ln hn. Lc ny shin nng cp EDGE ln W-CDMA v hon tt vic nng cp mng GSM ln 3G

2.4 Kt lun chng.

Cng ngh in thoi di ng ph bin nht th gii GSM ang gp nhiu

GSM

HSCSD

WCDMAData Speed

171.2Kbp

9.6Kbps

2Mbps

GPRS

Hnh 2.6. Qu trnh nng cp GSM ln W-CDMA


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tr v s sm c pht trin bng nhng cng ngh tin tin hn, h tr ti dch v nh Internet, truyn hnh...

Vi cng ngh 3G, cc nh khai thc mng c th cung cp nhiu dch v liu cho cc khch hng ca mnh, cc dch v hp dn ny lm cho cuc sng ch d dng hn. Nh , cc nh khai thc mng c th tng doanh thu trung btrn mt thu bao. Ngoi ra, 3G cn to kh nng cho cc nh khai thc cung ccc dch v c bit dnh ring cho cc thu bao ca mnh c c s truthnh ca khch hng .


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Cng ngh di ng th h ba W-CDMA

Trang 32

Chng3

CNG NGH DI NG TH H BA W-CDMA

3.1 Gii thiu cng ngh W-CDMA

Chng ny s gii thiu v cng ngh W-CDMA, cu trc mng W-CDMmng truy nhp v tuyn UTRAN, cc giao din v tuyn v c trng ring chng, ta s c ci nhn tng quan v mng W-CDMA 3G .

WCDMA (Wideband Code Division Multiple Access - truy cp a phn m bng rng) l cng ngh 3G hot ng da trn CDMA v c kh nng h tr

dch v a phng tin tc cao nh video, truy cp Internet, hi tho hnWCDMA nm trong di tn 1920 MHz -1980 MHz, 2110 MHz - 2170 MHz.

W-CDMA gip tng tc truyn nhn d liu cho h thng GSM bng cdng k thut CDMA hot ng bng tn rng thay th cho TDMA. Trong cng ngh thng tin di ng th h ba th W-CDMA nhn c s ng h ln nh vo tnh linh hot ca lp vt l trong vic h tr cc kiu dch v khc nc bit l dch v tc bit thp v trung bnh.

W-CDMA c cc tnh nng c s sau :- Hot ng CDMA bng rng vi bng tn 5MHz.- Lp vt l mm do tch hp c tt c thng tin trn mt sng mang.- H s ti s dng tn s bng 1.- H tr phn tp pht v cc cu trc thu tin tin.

Nhc im chnh ca W-CDMA l h thng khng cp php trong bng TD pht lin tc cng nh khng to iu kin cho cc k thut chng nhiu cc

trng lm vic khc nhau.

H thng thng tin di ng th h ba W-CDMA c th cung cp cc dch vi tc bit ln n 2MBit/s. Bao gm nhiu kiu truyn dn nh truyn dxng v khng i xng, thng tin im n im v thng tin a im. Vi knng , cc h thng thng tin di ng th h ba c th cung cp d dng cc d


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v mi nh : in thoi thy hnh, ti d liu nhanh, ngoi ra n cn cung cpdch v a phng tin khc.

Cc nh khai thc c th cung cp rt nhiu dch v i vi khch hng, t cdch v in thoi khc nhau vi nhiu dch v b sung cng nh cc dch v khlin quan n cuc gi nh th in t, FPT

Cng trnh nghin cu ca cc nc chu u cho W-CDMA bt u t CODIT (Code Division Multiplex Testbed : Phng th nghim a truy cp theo mv FRAMES (Future Radio Multiplex Access Scheme : K thut a truy cp vtuyn trong tng lai) t u thp nin 90. Cc d n ny tin hnh th nghcc h thng W-CDMA nh gi cht lng ng truyn.

Theo cc chuyn gia trong ngnh vin thng, ng ti 3G ca GSM lWCDMA. Nhng trn con ng , cc nh khai thc dch v in thoi di

KBit/s

i xng Khng i xng a phng

im n im a im

a phng tin di ng Qung b

Truyn hnh hingh

(Cht lng cao)

Truyn hnh hingh

(Cht lng thp)

m thoi hingh

in thoi

Truynhp

Internet

WWW

Thin t

FTPin

thoi IP

vv

Y t t xa

Th ting

Truy nhp c s d liu

Muahngtheo

CatalogVideo

Videotheoyucu

Boint

KaraokeISDN

Xut bnin t

Th in t FAX

Cc dch v phn phithng tin

Tin tc

D bothi tit

Thng tinlu lng

Thng tinngh ngi

Truynhnh ding

Truynthanh di

ng

Ting

S liu

H.nh

1.2

2.4

9.6

16

32

64

384

2M

Hnh 3.1 Cc dch v a phng tin trong h thng thng tin di ng th h


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phi tri qua giai on 2,5G. Th h 2,5G bao gm nhng g? l: d liu chumch gi tc cao (HSCSD), dch v v tuyn gi chung GPRS v EnhancData Rates for Global Evolution (EDGE).

3.2 Cu trc mng W-CDMA

H thng W-CDMA c xy dng trn c s mng GPRS. V mt chc nc th chia cu trc mng W-CDMA ra lm hai phn : mng li (CN) v mng tnhp v tuyn (UTRAN), trong mng li s dng ton b cu trc phn cca mng GPRS cn mng truy nhp v tuyn l phn nng cp ca W-CDM Ngoi ra hon thin h thng, trong W-CDMA cn c thit b ngi s d

(UE) thc hin giao din ngi s dng vi h thng. T quan im chun hUE v UTRAN u bao gm nhng giao thc mi c thit k da trn cng nv tuyn W-CDMA, tri li mng li c nh ngha hon ton da trn GSMiu ny cho php h thng W-CDMA pht trin mang tnh ton cu trn c cng ngh GSM.

UE (User Equipment)

Thit b ngi s dng thc hin chc nng giao tip ngi s dng v

PLMN,PSTNISDN

Internet

Cc

mng

MSC/VLR GMSC

GGSNSGSN

HLR

CN

RNC Node B

Node B

RNC Node B

Node B

IUbIUr

UTRAN

IU

USIM

USIM

CU

UE

UU

Hnh 3.2. Cu trc ca UMTS


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thng. UE gm hai phn :

- Thit b di ng (ME : Mobile Equipment) : L u cui v tuyn c

dng cho thng tin v tuyn trn giao din Uu.- Module nhn dng thu bao UMTS (USIM) : L mt th thng minh ch

thng tin nhn dng ca thu bao, n thc hin cc thut ton nhn thc, lu gikha nhn thc v mt s thng tin thu bao cn thit cho u cui.

UTRAN (UMTS Terestrial Radio Access Network)Mng truy nhp v tuyn c nhim v thc hin cc chc nng lin quan

truy nhp v tuyn. UTRAN gm hai phn t :

- Nt B : Thc hin chuyn i dng s liu gia cc giao din Iub v Uu. Ncng tham gia qun l ti nguyn v tuyn.

- B iu khin mng v tuyn RNC: C chc nng s hu v iu khin ti nguyn v tuyn trong vng (cc nt B c kt ni vi n). RNC cn l itruy cp tt c cc dch v do UTRAN cung cp cho mng li CN.

CN (Core Network)

- HLR (Home Location Register): L thanh ghi nh v thng tr lu githng tin chnh v l lch dch v ca ngi s dng. Cc thng tin ny bao gmThng tin v cc dch v c php, cc vng khng c chuyn mng v cthng tin v dch v b sung nh : trng thi chuyn hng cuc gi, s ln chuhng cuc gi.

- MSC/VLR (Mobile Services Switching Center/Visitor Location Register) :L tng i (MSC) v c s d liu (VLR) cung cp cc dch v chuyn mknh cho UE ti v tr ca n. MSC c chc nng s dng cc giao dch chuymch knh. VLR c chc nng lu gi bn sao v l lch ngi s dng cng nv tr chnh xc ca UE trong h thng ang phc v.

- GMSC (Gateway MSC) : Chuyn mch kt ni vi mng ngoi.- SGSN (Serving GPRS) : C chc nng nh MSC/VLR nhng c s dn


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cho cc dch v chuyn mch gi (PS).

- GGSN (Gateway GPRS Support Node) : C chc nng nh GMSC nhng ch

phc v cho cc dch v chuyn mch gi.Cc mng ngoi

- Mng CS : Mng kt ni cho cc dch v chuyn mch knh.- Mng PS : Mng kt ni cho cc dch v chuyn mch gi.

Cc giao din v tuyn

- Giao din CU : L giao din gia th thng minh USIM v ME. Giao din nytun theo mt khun dng chun cho cc th thng minh.

- Giao din UU : L giao din m qua UE truy cp cc phn t c nh ch thng v v th m n l giao din m quan trng nht ca UMTS.

- Giao din IU : Giao din ny ni UTRAN vi CN, n cung cp cho cc nhkhai 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 xukhc nhau.

- Giao din IUb : Giao din cho php kt ni mt nt B vi mt RNC. IUb ctiu chun ha nh l mt giao din m hon ton.

3.2.1 Mng truy nhp v tuyn UTRAN

UTRAN bao gm nhiu h thng mng con v tuyn RNS (Radio NetwoSubsystem). Mt RNS gm mt b iu khin mng v tuyn RNC v cc nodeCc RNC c kt ni vi nhau bng giao din Iur v kt ni vi node B bng

din Iub.


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3.2.1.1 c trng ca UTRAN

Cc c tnh ca UTRAN l c s thit k cu trc UTRAN cng nh giao thc. UTRAN c cc c tnh chnh sau :

- H tr cc chc nng truy nhp v tuyn, c bit l chuyn giao mm v

thut ton qun l ti nguyn c th ca W-CDMA.- m bo tnh chung nht cho vic x l s liu chuyn mch knh v chu

mch gi bng cch s dng giao thc v tuyn duy nht kt ni t UTRANc hai vng ca mng li.

- m bo tnh chung nht vi GSM.

- S dng c ch truyn ti ATM l c ch truyn ti chnh UTRAN.

3.2.1.2 B iu khin mng v tuyn UTRAN

RNC l phn t mng chu trch nhim iu khin ti nguyn v tuyn cUTRAN. RNC kt ni vi CN (thng thng l vi mt MSC v mt SGSN) qgiao din v tuyn Iu. RNC iu khin node B chu trch nhim iu khin ttrnh tc ngn cho cc ca mnh. Khi mt MS UTRAN s dng nhiu ti nguy

Node B

Node BRNC

Node B

Node BRNC

RNS

RNS

Iub Iur

UTRAN

MSC/VLR

GGSN

CN

IU CS

IU PS

UU

USIM

USIM

CU

UE

Hnh 3.3. Cu trc UTRAN


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v tuyn t nhiu RNC th cc RNC ny s c hai vai tr logic ring bt

- RNC phc v (Serving RNC) : SRNC i vi mt MS l RNC kt cui

ng ni Iu truyn s liu ngi s dng v bo hiu RANAP (phn ng mng truy nhp v tuyn) tng ng t mng li. SRNC cng l kt cui bo hiu khin ti nguyn v tuyn. N thc hin x l s liu truyn t lp kt nliu ti cc ti nguyn v tuyn. SRNC cng l CRNC ca mt node B no s dng MS kt ni vi UTRAN.

- RNC tri (Drif RNC) : DRNC l mt RNC bt k khc vi SRNC ikhin cc c MS s dng. Khi cn DRNC c th thc hin kt hp v phn

v m. DRNC khng thc hin x l s liu trong lp kt ni s liu m ch tuyn s liu gia cc giao din IUb v IUr . Mt UE c th khng c hoc c mt haynhiu DRNC.

3.2.1.3 Node B

Chc nng chnh ca node B l thc hin x l trn lp vt l ca giao dintuyn nh m ha knh, an xen, thch ng tc , tri phN cng thc h phn khai thc qun l ti nguyn v tuyn nh iu khin cng sut vng trong.

phn chc nng n ging nh trm gc ca GSM.

3.2.2 Giao din v tuyn

Cu trc UMTS khng nh ngha chi tit chc nng bn trong ca phn tmng m ch nh ngha giao din gia cc phn t logic. Cu trc giao din xy dng trn nguyn tc l cc lp v cc phn cao c lp logic vi nhau, iny cho php thay i mt phn ca cu trc giao thc trong khi vn gi nguycc phn cn li.


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3.2.2.1 Giao din UTRAN CN, IU

Giao din IU l mt giao din m c chc nng kt ni UTRAN vi CN. Iu chai kiu : Iu CS kt ni UTRAN vi CN chuyn mch knh v Iu PS ktUTRAN vi chuyn mch gi.

Cu trc IU CS

IU CS s dng phng thc truyn ti ATM trn lp vt l l kt ni v tuycp quang hay cp ng. C th la chn cc cng ngh truyn dn khc nhau nSONET, STM-1 hay E1 thc hin lp vt l.

- Ngn xp giao thc pha iu khin : Gm RANAP trn nh giao din S bng rng v cc lp ng dng l phn iu khin kt ni bo hiu SCCP, ptruyn bn tin MTP3-b, v lp thch ng bo hiu ATM cho cc giao din mSAAL-NNI.

- Ngn xp giao thc pha iu khin mng truyn ti : Gm cc giao thc

Giao thcng dng

Mngbo hiu

Mngs liu

Mngbo hiu

ALCAP

Lungs liu

Pha iukhin mngtruyn ti

Pha ngi sdng mngtruyn ti

Pha ngi sdng mngtruyn ti

Lp vt l

Lp mngv tuyn

Lp mngtruyn ti

Hnh 3.4. M hnh tng qut cc giao din v tuyn ca UTRAN


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hiu thit lp kt ni AAL2 (Q.2630) v lp thch ng Q.2150 nh cc gthc SS7 bng rng.

- Ngn xp giao thc pha ngi s dng : Gm mt kt ni AAL2 c dtrc cho tng dch v CS.

Cu trc IU PS

Phng thc truyn ti ATM c p dng cho c pha iu khin v pngi s dng.

- Ngn xp giao thc pha iu khin IU PS : Cha RANAP v vt mang bohiu SS7. Ngoi ra cng c th nh ngha vt mang bo hiu IP ngn xp nVt mang bo hiu trn c s IP bao gm : M3UA (SS7 MTP3 User AdaptioLayer), SCTP (Simple Control Transmission Protocol), IP (Internet Protocol) vALL5 chung cho c hai tu chn.

- Ngn xp giao thc pha iu khin mng truyn ti IU PS : Pha iu khinmng truyn ti khng p dng cho IU PS. Cc phn t thng tin s dng nha ch v nhn dng bo hiu AAL2 ging nh cc phn t thng tin c s dtrong CS.

- Ngn xp giao thc pha ngi s dng Iu PS : Lung s liu gi c ghchung ln mt hay nhiu AAL5 PVC (Permanent Virtual Connection). Phn ngs dng GTP-U l lp ghp knh cung cp cc nhn dng cho tng lung s gi. Cc lung s liu s dng truyn ti khng theo ni thng v nh a ch IP

3.2.2.2 Giao din RNC RNC, IUr

IUr l giao din v tuyn gia cc b iu khin mng v tuyn. Lc u g

din ny c thit k h tr chuyn giao mm gia cc RNC, trong qu t pht trin tiu chun nhiu tnh nng c b sung v n nay giao din IUr phim bo 4 chc nng sau :

- H tr tnh di ng c s gia cc RNC.


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- H tr knh lu lng ring.

- H tr knh lu lng chung.

- H tr qun l ti nguyn v tuyn ton cu.3.2.2.3 Giao din RNC Node B, IUb

Giao thc IUb nh ngha cu trc khung v cc th tc iu khin trong bngcho cc tng kiu knh truyn ti. Cc chc nng chnh ca IUb :

- Chc nng thit lp, b sung, gii phng v ti thit lp mt kt ni v tuu tin ca mt UE v chn im kt cui lu lng.

- Khi to v bo co cc c th , node B, kt ni v tuyn.- X l cc knh ring v knh chung.

- X l kt hp chuyn giao.

- Qun l s c kt ni v tuyn.


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3.3 Kt lun chng .

Chng ny gii thiu c cng ngh W-CDMA , cu trc mn

W-CDMA , mng truy nhp v tuyn UTRAN v giao din v tuyn .Theo bo in t Vietnamnet (bi vit ngy 11/3/2005) th ngy 10/3/2005

va qua, B Bu Chnh Vin Thng tin hnh nghim thu ti xy dng tchun thit b u cui thng tin di ng WCDMA (UTRA-FDD) m s 49-0KTKT-TC dnh cho cng ngh 3G.

Theo nh gi ca cc thnh vin phn bin, vic xy dng v hon thncng trnh l mt vic lm cn thit, c ngha v c bit l kh thi trong

on hin nay, khi nhu cu pht trin ln 3G l mt xu hng tt yu Vit Nnht l cc nh di ng mng GSM.


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Cc gii php k thut trong W-CDMA

Trang 43

Chng 4

CC GII PHP K THUT TRONG W-CDMA

4.3 Gii thiu .

Trong chng ny chng ta s tm hiu cc k thut trong WCDMA, cc kthut m ha, iu ch, nguyn l tri ph, cu trc phn knh v k thut truy ngi trong WCDMA.

4.4 M ha

4.2.1 M vng

M khi l b m ha chia dng thng tin thnh nhng khi tin (message) c bit. Mi tin c biu din bng mt khi k thnh phn nh phn u = (u1,u2,..,un), uc gi l vector thng tin. C tng cng 2k vector thng tin khc nhau. B mha s chuyn vector thng tin u thnh mt b n thnh phn v = (v1,v2,...,vn) cgi l t m. Nh vy ng vi 2k vector thng tin s c 2k t m khc nhau. Tphp 2k t m c chiu di n c gi l mt m khi (n,k). T s R = k/n c gt s m, R chnh l s bit thng tin a vo b gii m trn s bit c truyn. D

bit ra ch ph thuc vo k bit thng tin vo, b gii m khng cn nh v c c thc hin bng mch logic t hp. M vng l mt tp con ca m khi tutnh.

M vng l phng php m ha cho php kim tra d vng (CRC CyclRedundance Check) v ch th cht lng khung cc khung bn tin.

M ha m vng (n,k) dng h thng gm ba bc :(1). Nhn a thc thng tin u(x) vi xn-k .(2). Chia xn-k .u(x) cho a thc sinh g(x), ta c phn d b(x).(3). Hnh thnh t m b(x) + xn-k

Tt c ba bc ny c thc hin bng mch chia vi thanh ghi dch (ntng c hm hi tip tng ng vi a thc sinh g(x).


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S mch m ha vng :

Nguyn l hot ng :

Bc 1 : Cng ng cho thng tin qua mch, k ch s thng tin u0,u1,...,un-k c dch vo mch t thit b u cui nhn trc u(x) vi xn-k . Ngay sau khi thng tin c a vo mch th n-k ch s cn li trong thaghi l nhng con s kim tra chn l.

Bc 2 : Ct t ng hi tip bng cch iu khin cho cc cngi h (khng cho thng tin qua).

Bc 3 : Dch cc con s kim tra chn l v a ra ng truyCc ch s kim tra ny kt hp vi k ch s thng tin to thnh vector m

G1

b1 + b0 + b2 +

G2 Gn-k-1

+ bn-k-1

Thng tinxn+k .u(x) Cc s kim

tra chn l

+

Mt khu ca thanh ghi dch

Cng XOR

Mi lin ktg = 1 : C lin ktg = 0 : Khng lin kt

g

Hnh 4.1. Mch m ha vng vi a thc sinh

g(x) = 1 + g1x + g2x2

+ ...+ gn-k-1xn-k-1

+ xn-k

Cng


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4.2.2 M xon

M xon (Convolutional Code) (n,k,m) cng c n u ra, k u vo nh m

khi (n,k) nhng n u ra ca m xon ph thuc khng ch vo k u vo ti gian m cn ph thuc vo m khi bn tin trc . M xon (n,k,m) c xdng bi mch dy. Mch ny dng thanh ghi dch m bit lm b nh, cc u ra ccc phn t nh c cng vi nhau theo quy lut nht nh to nn chui sau cc chui ny c ghp xen vi nhau to nn chui m u ra.

4.2.3 M Turbo

M ha Turbo ch c s dng trong cc h thng thng tin di ng th h

khi hot ng tc bit cao vi yu cu t s li bit BER nm trong khong -3 n 10-6. B m ha turbo thc cht l b m xon mc ni song song PCCC(Parallel Concatenated Convolutional Code) vi cc b m ha thnh phn 8 trnthi c s dng.

4.3 iu ch BIT/SK v QPSK

4.3.1 iu ch BIT/SK

Trong mt h thng iu ch BIT/SK (BPSK Binary Phase Shift Keying) ctn hiu s1(t) v s2(t) c s dng biu din cc gi tr nh phn. Ta c

t f T E t s c

b

bi .2cos.

2)( (4.1)

Trong :

T b : rng bng thng.

E b : Nng lng ca mt bit.

t : Gc pha thay i theo tn hiu iu ch, l gc pha ban u.

2,1,0,.1 iT t it b

Mt cp sng sin i pha 1800 nh trn gi l mt cp tn hiu i cc.


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Lung s tc bit R b c a qua b chuyn i v tn hiu NRZ (01,

1 -1), sau nhn vi sng mang c tn hiu iu ch BIT/SK.

Chn mt tn hiu l c s l trc chun:

t f T

t u cb

2cos.2)(1 (4.2)

Ta c :

t ut d E t S bi 1.)( (4.3)

Khong cch gia hai tn hiu :

Xc sut li trong BPSK:

0

221

N E erfc P be (4.4)

Vi :Eb l nng lng ca bit .

N0 mt xc sut nhiu trng.

4.3.2 iu ch QPSK

Hnh 4.2. S nguyn l iu ch BPSK

Lung s c hai

Si(t)

cb

f T

b E .2cos2

NRZ

0b E b E

Hnh 4.3 Khong cch gia hai tn hiu BPSK


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Tn hiu iu ch QPSK c dng:

T t t

T t it f T E

t S cQPSK ;0,0

0,412.2cos2

)( (4.5)

Trong

E b : Nng lng mt bit.T b : Thi gian mt bit. E = 2E b : Nng lng tn hiu pht i trn mt k hiu.T = 2T b : Thi gian ca mt k hiu.

f c : Tn s sng mang, : gc pha ban u.i = 1, 2, 3, 4.

Bin i lng gic ta c phng trnh dng tng ng nh sau :

T t t

T t t f iT E

t S cQPSK ;0,0

0,.2cos4

.12cos2 (4.6)

Nu ta chnQ1v Q2 l cc hm nng lng c s trc giao chun :

T t t f T

t Q

T t t f T

t Q

c

c

0,.2cos2

0,.2sin2

2

1

(4.7)

Ta c th biu din tn hiu iu ch QPSK bng bn im trong khng gtn hiu vi cc to xc nh nh sau :

.4,3,2,1,

4.12cos4

.12sin

2

1 ii E Q

i E QS QPSK

(4.8)

Quan h ca cp bit iu ch v ta ca cc im tn hiu iu ch Qtrong khng gian tn hiu th hin bng sau :


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To cc im tn hiuCp bit vo

0 t TPha ca tnhiu QPSK

im tn hiuSi Q1 Q2

00 /4 S1+ 2/ E + 2/ E

01 3 /4 S2 + 2/ E - 2/ E

11 5 /4 S3 - 2/ E - 2/ E

10 7 /4 S4 - 2/ E + 2/ E

Xc sut li trong QPSK:

0,

2

N

E Q P bQPSK e

Ta thy xc sut li ca BPSK v QPSK l nh nhau. Tuy nhin, vi QPSK thiu sut bng thng gp 2 ln BPSK. Bng thng ca QPSK xp x bng Rb.

4.4 Tri ph trong W-CDMA

4.4.1 Gii thiu

Tn hiu sau tri ph chim mt rng bng truyn dn ln hn gp n

ln rng bng ti thiu cn thit truyn thng tin i. S tri ph chin bi tn hiu tri ph c gi l m tri ph, m tri ph ny c lp vliu.Ti pha thu, vic nn ph (khi phc li thng tin ban u) c thc hins tng quan gia tn hiu thu c vi bn sao ng b ca m tri ph s pha pht.

Trong cc h thng thng tin vic s dng hiu qu bng tn l vn quan tm hng u. Cc h thng c thit k sao cho rng bng tn cng

cng tt. Trong W-CDMA tng tc truyn d liu, phng php a truy kt hp TDMA v FDMA trong GSM c thay th bng phng php a truy c phn chia theo m CDMA hot ng bng tn rng (5MHz) gi l h thng thtin tri ph. i vi cc h thng thng tin tri ph (SS :Spread Spectrum) rng bng tn ca tn hiu c m rng trc khi c pht. Tuy rng bng tn


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ln rt nhiu nhng lc ny nhiu ngi s dng c th dng chung mt bngtri ph, do m h thng vn s dng bng tn c hiu qu ng thi tn c cc u im ca tri ph. pha thu, my thu s khi phc tn hiu gc cch nn ph ngc vi qu trnh tri ph bn my pht.

C ba phng php tri ph c bn sau :

- Tri ph dy trc tip (DSSS : Direct Sequence Spreading Spectrum) : Thhin tri ph bng cch nhn tn hiu ngun vi mt tn hiu gi ngu nhin c chip cao hn rt nhiu so vi tc bit.

- Tri ph nhy tn (FHSS : Frequency Hopping Spreading Spectrum) : H

thng FHSS thc hin tri ph bng cch nhy tn s mang trn mt tp cc tMu nhy tn c dng m ngu nhin. Tn s trong khong thi gian mt chiC c c nh khng i . Tc nhy tn c th thc hin nhanh hoc chm, th thng nhy tn nhanh nhy tn thc hin tc cao hn tc bit ca bcn trong h thng nhy tn thp th ngc li.

- Tri ph nhy thi gian (THSS :Time Hopping Spreading Spectrum) : Thchin tri ph bng cch nn mt khi cc bit s liu v pht ngt qung trong

hay nhiu khe thi gian. Mu nhy tn thi gian s xc nh cc khe thi gian s dng truyn dn trong mi khung.

Trong h thng DSSS, tt c cc ngi s dng cng dng chung mt bng v pht tn hiu ca h ng thi. My thu s dng tn hiu gi ngu nhin chxc ly ra tn hiu bng cch nn ph. Cc tn hiu khc xut hin dng n ph rng, cng sut thp ging tp m. Trong cc h thng FHSS v THSS ngi s dng c n nh mt m ngu nhin sao cho khng c cp my pht

dng chung tn s hoc khe thi gian, nh vy cc my pht s trnh b xung Ni cch khc DSSS l kiu h thng ly trung bnh, FHSS v THSS l kiu thng trnh xung t. H thng thng tin di ng cng ngh CDMA ch s dDSSS nn ta ch xt k thut tri ph DSSS.


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4.4.2 Nguyn l tri ph DSSS

Tri ph dy trc tip (DSSS : Direct Sequence Spreading Spectrum) : Th

hin tri ph bng cch nhn tn hiu ngun vi mt tn hiu gi ngu nhin c chip cao hn rt nhiu so vi tc bit

Tc chip tn hiu gi ngu nhin v tc bit c tnh theo cng thc saR C = 1/TC (4.9)R b = 1/T b (4.10)

Trong :R C : tc chip tn hiu gi ngu nhin.

R b: tc bit.TC : thi gian mt chip.T b : thi gian mt bit.

T b= Tn

T b= Tn

Tc

T b: Thi gian mt bit ca lung s cn phtTn : Chu k ca m gi ngu nhin dng cho tri phTC : Thi gian mt chip ca m tri ph

Hnh 4.4. Tri ph chui trc tip (DSSS)


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4.4.3 M tri ph

Cc tn hiu tri ph bng rng c to ra bng cch s dng cc chui

gi tp m PN ( Pseudo Noise). M gi tp m cn c gi l m gi ngu nhin doc cc tnh cht thng k ca tp m trng AWGN ( Additive White Gaussian Noise)v c biu hin ngu nhin, bt xc nh. Tuy nhin my thu cn bit m ny bn sao mt cch chnh xc v ng b vi m c pht gii m bn tin. Vm gi ngu nhin phi hon ton xc nh.

M gi ngu nhin c to ra bng cc b thanh ghi dch c mch hi ttuyn tnh (LFSR : Linear Feedback Shift Register ) v cc cng XOR.

Mt chui thanh ghi dch hi tip tuyn tnh c xc nh bi mt a thto m tuyn tnh bc m (m > 0) :

011

1 ... g x g x g x g x g m

m

m

m (vi gm = g0 = 1) (4.11)xm : n v tr.

Gi s ta np chui gi tr khi u cho thanh ghi dch :

S0 = {S0(1), S0(1), S0(m)}

ciSi(1) Si(2)

g1 g2 gm-1

ci-m

n biu ch

Si(m)

Hnh 4.5. Mch thanh ghi dch to chui PN

Si(j) : L gi tr phn t nh j trong thanh ghi dch xung ng h i.gi = 0 : kha m, gi = 1 : kha ng.


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Gi tr u ra trong (m -1) xung ng h u tin l :

C0 = S0(m)

C1 = S0(m-1).Cm-1 = S0(1)

Ti xung ng h th i (i > m-1) ta c trng thi ca thanh ghi dch :

Si(m) = Si-1(m-1) = Si-2(m-2) = = Si-m+1(1) (4.12)

Si-m+1(1) = g1.Si-m(1) + g2.Si-m(2) + + Si-m(m) (gm = 1)

=> Si(m) = g1.Si-m(1) + g2.Si-m(2) + + Si-m(m) (4.13)

p dng cng thc (4.12), ta c :

Si(m) = g1.Si-1(m) + g2.Si-2(m) + + Si-m(m) (4.14)

Gi tr u ra ti xung th i chnh l gi tr phn t nh Si(m) ca thanh ghidch :

=> Ci = g1.Ci-1 + g2.Ci-2 + + Ci-m (4.15)Hay :

Ci+m = g1.Ci+m-1+ g2.Ci+m-2+ + Ci (4.16)

Tc ca mch nh trn b hn ch v tc do tng thi gian tr trongthanh ghi v cc cng loi tr ng hi tip. hn ch thi gian tr, nngtc ca mch to m ngu nhin ta c th s dng s mch sau :

Si(1) Si(2)

g2 gm-1

ci

n biu ch

Si(m)

Hnh 4.6. Mch thanh ghi dch to chui PN tc cao

Si(j) : L gi tr phn t nh j trong thanh ghi dch xung ng h i.gi = 0 : kha m, gi = 1 : kha ng.

g1


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4.4.4 Cc hm trc giao

Cc hm trc giao c s dng ci thin hiu sut s dng bng tn c

thng DSSS. Trong h thng thng tin di ng W-CDMA mi ngi s dng m phn t trong cc hm trc giao. Hm Walsh v cc chui Hadamard to nn mtp cc hm trc giao. Trong W-CDMA cc hm Walsh c s dng theo hai ccl m tri ph hoc cc k hiu trc giao.

Cc hm Walsh c to ra bng cc ma trn vung c bit gi c gcc ma trn Hadamard. Cc ma trn ny cha mt hng ton bit 0, cc hng cli c s bit 1 v s bit 0 bng nhau. Hm Walsh c cu trc cho di kh

N = 2 j

, trong j l mt s nguyn dng.T hp m cc hng ca ma trn l cc hm trc giao c xc nh theo m

trn Hadamard nh sau :

N N

N N N H H

H H H H H H 2421 ,

0110110010100000

,1000

,0

Trong N H l o c s hai ca H N.4.5 Cu trc phn knh ca WCDMA

Cng nh trong cc h thng thng tin di ng th h hai, cc knh thng trong WCDMA c chia ra lm hai loi tu thuc vo quan im nhn nhn. Thquan im truyn dn ta s c cc knh vt l cn theo quan im thng tin ta scc knh truyn ti.

Lp vt l nh hng ln n s phc tp ca thit b v mt m bonng x l bng tn c s cn thit trm gc v trm u cui. Trn quan cc h thng thng tin di ng th h ba l cc h thng bng rng, v vy khngthit k lp vt l ch cho mt dch v thoi duy nht m cn m bo tnh linhcho cc dch v tng lai.


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4.5.1 Knh vt l

4.5.1.1 Knh vt l ring ng ln

Knh vt l ng ln gm mt hay nhiu knh s liu vt l ring (DPDCv mt knh iu khin vt l (DPCCH).

Knh iu khin vt l (DPCCH)

Knh iu khin vt l ng ln c s dng mang thng tin iu khlp vt l. Thng tin ny gm : cc bit hoa tiu h tr nh gi knh cho tsng nht qun, cc lnh iu khin cng sut (TCP : Transmit Control Powethng tin hi tip (FBI : Feedback Information) v mt ch th kt hp khun dtruyn ti (TFCI).

Thng s k xc nh s bit trn khe ca DPDCH/DPCCH ng ln. Mkhung c di 10ms c chia thnh 15 khe, mi khe di Tslot = 2560 chip ngvi 666s, tng ng vi mt chu k iu khin cng sut. Nh vy rnggn bng vi rng khe GSM (577s). Cc bit FBI c s dng khi s d phn tp pht vng kn ng xung. C tt c 6 cu trc khe cho DPCCH

Hoa tiu TFCI FBI TCP N pilot bit NTFCI bit NFBI bit NTPC

S liu Ndata bit

Tkhe = 2560 chip, 10.2k bit (k = 06)

Khe #0 Khe #1 Khe #14Khe #i

Mt khung v tuyn : Tf = 10ms

DPDCH

DPCCH

Hnh 4.7. Cu trc khung v tuyn ca DPDCH/DPCCH ng ln


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ln. C cc tu chn sau : 0, 1 hay hai bit cho FBI v c hoc khng cc bit TFCICc bit hoa tiu v TPC lun lun c mt v s bit ca chng c thay i lus dng ht khe DPCCH.

Cu trc cc trng ca DPCCH :

Khundngti #i

Tc bit knh(kbit/s)

Tc k hiuknh

SF S bit/khung

S bit/khe

N pilot NTPC NTFCI NFBI S khe c phttrn khung vtuyn

0 15 15 256 150 10 6 2 2 0 150A 15 15 256 150 10 5 2 3 0 10 140B 15 15 256 150 10 4 2 4 0 8 9

1 15 15256

150 10 8 2 0 0 8 162 15 15 256 150 10 5 2 2 1 152A 15 15 256 150 10 4 2 3 1 10 142B 15 15 256 150 10 3 2 4 1 8 93 15 15 256 150 10 7 2 0 1 8 154 15 15 256 150 10 6 2 0 2 8 155 15 15 256 150 10 5 1 2 2 155A 15 15 256 150 10 4 1 3 2 10 14

5B 15 15 256 150 10 3 1 4 2 8 9

Knh s liu vt l ring DPDCH

Knh truyn s liu cho ngi s dng, tc s liu ca DPDCH c th i theo khung. Thng thng i vi cc dch v s liu thay i, tc s ca knh DPDCH c thng bo trn knh DPCCH. DPCCH c pht lin tv thng tin v tc trng c pht bng vi ch th kt hp khun dng truti (TFCI), l thng tin DPCCH v tc s liu khung DPDCH hin hnh. Ngii m TCFI khng ng th ton b khung s liu b mt. Tuy nhin tin cy TCFI cao hn s liu nn t khi xy ra mt TCFI.

Cu trc cc trng ca DPDCH nh sau :


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Khundng ti #i

Tc bitknh (kbit/s)

Tc khiu knh

SFS bit/khung

S bit/khe

Ndata

0 15 15 256 150 10 10

1 30 30 128 300 20 20

2 60 60 64 600 40 40

3 120 120 32 1200 80 80

4 240 240 16 2400 160 160

5 480 480 8 4800 320 320

6 960 960 4 9600 640 640

4.5.1.2 Knh vt l chung ng ln

Knh truy cp ngu nhin PRACH

Knh truy cp ngu nhin vt l (PRACH) c s dng mang RACH

- Pht RACH : Pht truy nhp ngu nhin da vo phng php ALOHA the phn khe vi ch th bt nhanh. C hai khung th c 15 khe truy nhp v khocch gia chng l l 5120 chip. Cc lp cao cung cp thng tin v khe truy nhp dng hin thi.


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- Phn tin t ca RACH : Phn tin t ca cm truy nhp ngu nhin gmln lp mt ch k.

- Phn bn tin ca RACH : Khung v tuyn phn bn tin 10ms c chia th15 khe, mi khe di Tslot = 2560 chip. Mi khe gm hai phn : phn s liu mangthng tin lp 2 v phn iu khin mang thng tin lp 1. C hai phn c png thi. Phn s liu gm 10.2k bit vi k = 0, 1, 2, 3. Phn iu khin gm 8 bithoa tiu h tr s nh gi cho tch sng nht qun v hai bit TFCI . Tng sTFCI trong bn tin truy nhp ngu nhin l 30. Gi tr ca TFCI tng ng vi m

Knh tru nh #0

#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14

Khung v tuyn 10ms Khung v tuyn 10ms

5120 chip

Pht truy cp ngu nhin

Knh tru nh #1

Knh tru nh #7

Knh tru nh #8

Knh tru nh

Hnh 4.8. S th t cc khe truy nhp RACH v khong cch gia chng




Tin t Tin t Tin t

Tin t Tin t

Phn bn tin

Phn bn tin

4096 chi

4096 chi

10ms (Mt khung v tuyn)

20ms (Hai khung v tuyn)

Hnh 4.9. Cu trc pht truy nhp ngu nhin

Tin t


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khun dng truyn ti nht nh ca bn tin truy nhp hin thi.

Cc trng s liu ca phn bn tin RACH :

Khun

dng khe #i

Tc bit

knh (kbit/s)

Tc k hiu

knh (kbit/s)

SF S bit/ khung S bit/ khe Ndata

0 15 15 256 150 10 10

1 30 30 128 300 20 20

2 60 60 64 600 40 40

3 120 120 32 1200 80 80

Trng iu khin phn bn tin RACH :

Khundng khe #i

Tc bitknh (kbit/s)

Tc khiu knh(kbit/s)

SF S bit/khung

S bit/khe

N pilot NTFCI

0 15 15 256 150 10 8 2

S liu Ndatabit

Khe #0 Khe #1 Khe #14Khe #i

Khung v tuyn phn bn tin TRACH= 10

Hoa tiu N pilotbit

Tslot = 2560 chip, 10.2k bit (k=0..3)

S liu

iu khin

Hnh 4.10. Cu trc khung v tuyn phn bn tin RACH


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Knh gi chung PCPCH

Knh gi chung vt l c s dng mang CPCH. PCPCH thc cht l

m rng ca RACH. S khc nhau c bn so vi RACH l knh ny c th dtrc nhiu khung v c s dng iu khin cng sut.

- Pht CPCH : Pht CPCH da trn nguyn tc DSMA CD (DSMA Collision Detection) vi ch th bt nhanh. Pht truy nhp ngu nhin CPCH gmt hay nhiu tin t truy nhp (AP : Access Preamble) di 4096 chip, mt tin pht hin tranh chp (CDP : Collisiion Detection Preamble) di 4096 chip, mt tit iu khin cng sut (PCP : Power Control Preamble) di t 0 n 8 khe v m

bn tin c di kh bin Nx10ms.

- Phn tin t truy nhp CPCH : Phn tin t truy nhp ngu nhin CPtng t nh ca RACH. S chui c s dng y c th nh hn s cc s dng tin t RACH.

- Phn tin t pht hin tranh chp : Phn ny ging nh phn tin t RACH

- Phn tin t iu khin cng sut : L cc tin t iu khin cng sut cdi ly gi tr t 0 n 8 khe c thit lp bi cc bit cao.

- Phn bn tin CPCH : Gm cc khung bn tin 10ms, s khung bn tin ny lp cao hn quy nh. Mi khung 10ms c chia ra 15 khe di 2560 chip, mi kgm hai phn : phn s liu mang thng tin cc lp cao v phn iu khin m

Phn bn tin

0 hay 8 khe N.10ms

Tin t truy nhp

Tin t phn gii va chm

DPCCH

DPDCH

Hnh 4.11 Cu trc pht a truy nhp ngu nhin CPCH


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thng tin cc lp thp. Phn s liu v phn iu khin c pht ng thi.

4.5.1.3 Knh vt l ring ng xung (DPCH)

Knh ring ng xung c to bi lp hai v cc lp trn. Mt khung kring ng xung di 10ms c chia ra lm 15 khe, mi khe di 2560 chip tng vi mt chu k iu khin cng sut. Cu trc khung ca knh ring xung c th hin hnh sau :

4.5.1.4 Knh vt l chung ng xung

Knh hoa tiu chung (CPICH)

Knh hoa tiu chung l knh vt l ng xung c tc c nh ma

chui bit/k hiu c nh ngha trc.

Khe #0 Khe #1 Khe #i Khe #14

S liu 1 TPC TFCI S liu 2 Hoa tiu Ndata bit NTPCbit NTFCIbit Ndata2bit N pilotbit

DPDCH DPCCH DPDCH DPCCH

Tslot = 2560 chip, 10.2k bit (k = 0..7)

Hnh 4.12. Cu trc khung ca DPCH ng xung.

Mt khung v tuyn Tf = 10ms


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C hai kiu knh hoa tiu chung l knh hoa tiu chung s cp v knh hotiu chung th cp, phn bit v lnh vc s dng v cc hn ch i vi tnh nvt l ca chng.

- Knh hoa tiu chung s cp : c ngu nhin ha bi m ngu nhin s cv lun c s dng cng mt m nh knh. Mi c mt knh v chng

pht qung b trn ton b .- Knh hoa tiu chung th cp : M ngu nhin ha c th l s cp hoc t

cp v s dng m nh knh tu . Mt c th khng c hoc c nhiu knChng ch c pht trong mt phn .

Knh vt l iu khin chung s cp (P-CCPCH)

L knh vt l ng xung c tc c nh (30 kbit/s) c s dng mang BCH.

# # Khe #14

Chui k hiu c nh ngha trc

Tslot = 2560 chip, 20 bit = 10 k hiu

Hnh 4.13. Cu trc khung ca DPCH ng xung



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Knh vt l iu khin chung th cp (S-CCPCH)

Knh vt l iu khin chung th cp s dng mang thng tin FACH PCH. C hai kiu knh S-CCPCH l kiu c mang TFCI v kiu khng mang TFC

Knh ng b (SCH)


S liu 18 bit

Tslot = 2560 chip, 20 bit

Hnh 4.14. Cu trc khung ca knh vt l iu khin chung s cp


Tx tt

256 chi


S liu Ndata bit

Tslot = 2560 chip, 20.2k bit (k = 0..6)

Hnh 4.15. Cu trc khung ca S-CCPCH


TFCI NTFCI bit Hoa tiu Npilot bit


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Knh ng b l knh mang tn hiu tm ng xung. SCH gm hai kcon l SCH s cp v SCH th cp. Cc khung 10ms ca SCH s cp v th cc chia thnh 15 khe, mi khe di 2560 chip.

SCH s cp gm mt m ng b s cp PSC (Primary Synchronization) iu ch 256 chip, m ng b s cp nh nhau trong mi h thng. SCH thgm 15 chui m c iu ch c di 256 chip. Cc m ng b th (Secondary Synchrization Code) pht ng thi vi SCH s cp. Mi SSC chn t tp ca 16 m di 256. Chui ny SCH th cp ch th m ngu nhng xung ca thuc nhm m no.

Knh vt l dng chung ng xung (PDSCH)

Knh vt l dng chung ng xung (PDSCH) c s dng mang kdng chung ng xung. PDSCH lun c dng chung vi nhiu knh khc trc s ghp knh theo m.

acp

acs1.0

acp

acs1.1

acp

acs1.14

SCH s

SCH th cp

256 chip

2560 chip

Mt khung v tuyn SCH 10ms

Khe #0 Khe #1 Khe #14

. . . .

Hnh 4.16. Cu trc khung knh ng b

ac p : M ng b s cp ( Primary Synchrization Code)acsi,k : M ng b th cp (Secondary Synchrization Code)


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Knh ch th bt (AICH)

Knh ch th bt c s dng mang thng tin ch th bt. Ch th bt As tng ng vi mt ch k s trn knh PRACH hoc PCPCH. AICH gm mt chlp ca 15 khe truy nhp lin tip (AS = Access Slot), mi khe di 40 bit. Mi kgm hai phn : phn ch th bt (AI) gm 32 gi tr thc a0,a1,..,a31 v mt phnkhng s dng gm 8 gi tr thc a32,a33,..a39.

Knh ch th tm gi (PICH)

AS #0 AS #1 AS #0 AS #14AS #i

a1 a2 a30 a31 a32 a33 a38 a39

Phn AI Phn khng s dng

5120 chip, 40 bit

20ms

AS #0AS #14

Hnh 4.18. Cu trc knh ch th bt AICH


S liu Ndata bit

Tslot = 2560 chip, 20.2k bit (k=0..6)

Hnh 4.17. Cu trc khung ca PDSCH



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Knh ch th tm gi l knh vt l c tc c nh c s dng macc ch th tm gi (PI). Mt khung PICH di 10ms cha 300 bit, trong 288 bc s dng mang thng tin, 12 bit cn li khng c nh ngha.

4.5.2 Knh truyn ti

4.5.2.1 Knh truyn ti ring

Knh truyn ti ring duy nht l knh DCH c s dng mang thng t cc lp trn lp vt l ring cho ngi s dng. Thng tin bao gm s liu dch v hin thi v cc thng tin iu khin lp cao. Knh truyn ti ring c tnh nng c trng sau :

- iu khin cng sut nhanh theo tng khung.- Thay i tc s liu theo tng khung v kh nng pht n mt phn

mt on bng cch thay i hng anten ca h thng anten thch ng.- H tr chuyn giao mm.

4.5.2.2 Knh truyn ti chung

C su kiu knh truyn ti chung c nh ngha trong UTRA. Cc kn

truyn ti chung khng c chuyn giao mm, tuy vy mt s knh c iu khcng sut. So vi h thng thng tin di ng th h hai, cc knh ny c mtim khc nh truyn dn gi cc knh chung, dng chung mt knh xung pht s liu gi

Mt khung v tuyn 10ms

288 bit ch th 12 bit(khng nh ngha)

b0 b1 b287 b288 b299

Hnh 4.19. Cu trc knh ch th tm gi


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Knh qung b (BCH)

Knh qung b BCH (Broadcast Channel) l mt knh truyn ti c s d

pht cc thng tin c th UTRA trong mt .Knh truy nhp ng xung (FACH)

Knh truy nhp ng xung FACH (Forward Access Channel) l mt kntruyn ti ng xung mang thng tin iu khin n cc UE nm trong mt trc. Knh FACH cng c th truyn cc gi s liu. Khi c nhiu knh FACcc knh b sung c th c tc bit cao hn. FACH khng s dng iu khcng sut nhanh v cc thng tin c pht phi cha thng tin nhn dng tro

bng.Knh tm gi (PCH)

Knh tm gi PCH (Paging Channel) l mt knh truyn ti ng xung mas liu lin quan n th tc tm gi.

Knh truy nhp ngu nhin (RACH)

Knh truy cp ngu nhin RACH (Random Access Channel) l knh truyn t

ng ln c s dng mang thng tin iu khin t UE. Knh ny cng cs dng pht i cc cm nh s liu gi t UE. hot ng ng, h th phi thu c knh truy cp ngu nhin t ton b vng ph ca .

Knh gi chung ng ln (CPCH)

Knh gi ng ln CPCH (Common Packet Channel) l mt m rng cknh RACH mang s liu ca ngi s dng c pht theo gi trn ng Knh CPCH cng vi knh FACH ng xung to nn cp knh truyn

liu.

Knh ng xung dng chung (DSCH)

Knh ng xung dng chung DSCH (Dedicated Shared Channel) l knhtruyn ti mang thng tin ca ngi s dng, ngoi ra DSCh cng c th m


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thng tin iu khin. DSCH h tr iu khin cng sut nhanh v c th c dchung cho nhiu ngi s dng.

4.5.2.3 Sp xp knh truyn ti ln knh vt l

Trong qu trnh truyn dn thng tin, cc knh truyn ti c t ln cc kvt l th hin s sau :

Knh ring (DCH) c sp xp ln hai knh vt l. Knh s liu vt l ri

mang thng tin cc lp cao, cn knh iu khin vt l ring mang thng tin ca lvt l cn thit.

4.6 Truy nhp gi trong W-CDMA

4.6.1 Tng quan v truy nhp gi trong W-CDMA

CC KNH VT LCC KNH TRUYN TI

Knh vt l iu khin chung s cp(P-CPCH)

Knh vt l iu khin chung th cp(S-CPCH)

Knh vt l truy cp ngu nhin(PRACH)

Knh s liu vt l ring (DPDCH)

Knh iu khin vt l ring (DPCCH)

Knh vt l ng xung dng chung(PDSCH)

Knh gi chung vt l (PCPCH)Knh ng b (SCH)Knh hoa tiu chung (CPICH)Knh ch th bt (AICH)Knh ch th tm gi (PICH)Knh pht hin tranh chp/ch th nnh knh (CD/CA-ICH)

BCH

FACH

PCHRACH

DCH

DSCH

CPCH

Hnh 4.25. Sp xp cc knh truyn ti ln cc knh vt l


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Truy nhp gi trong W-CDMA cho php cc vt mang khng phi thi giathc s dng ng cc knh chung, ring v dng chung. Vic s dng cc kkhc nhau c iu khin bi b lp biu gi PS (Packet Scheduler). B lp bgi thng c t RNC v ti y vic lp biu gi c th thc hin hiucho nhiu , ngoi ra y cng xem xt cc kt ni chuyn giao mm.

B lp biu gi c cc chc nng chnh sau :

- Phn chia dung lng ca giao din v tuyn gia cc ngi s dng.

- Phn chia cc knh truyn ti s dng cho truyn dn s liu ca tngi s dng.

- Gim st cc phn b gi v ti h thng.

4.6.2 Lu lng s liu gi

Truy nhp gi s dng cho cc dch v khng theo thi gian thc, nhn t quim giao din v tuyn n c cc thuc tnh in hnh sau :

- S liu gi c dng cm, tc bit yu cu c th bin i rt nhanh.

- S liu gi cho php tr ln hn cc dch v thi gian thc. V th s liu

l lu lng c th iu khin c xt theo quan im mng truy nhp v tuy

- Cc gi c th c pht li bi lp iu khin kt ni v tuyn (RLC). ny cho php s dng cht lng ng truyn v tuyn km hn v t s li khcao hn so vi cc dch v thi gian thc.

Lu lng gi c c trng bi cc thng s sau :

- Qu trnh n ca phin.

- S cuc gi n phin.- Thi gian c gia cc cuc gi.- S gi trong mt cuc gi gi.- Khong thi gian gia hai gi trong mt cuc gi gi.- Kch thc gi.


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4.6.3 Cc phng php lp biu gi

Chc nng lp biu gi l phn chia dung lng giao din v tuyn kh dgia cc ngi s dng. B lp biu gi c th quyt nh tc bit phn b vgian phn b. Thut ton lp biu gi trong W-CDMA c thc hin theo phng php : phn chia theo m v phn chia theo tn s. Trong phng ph phn chia theo m, khi c nhu cu tng dung lng th tc bit phn b cho ngs dng s gim i. Trong phng php phn chia theo thi gian biu dung lc dnh cho mt s t ngi theo tng thi im, nh vy ngi s dng cc tc bit cao nhng ch c th s dng trong thi gian ngn. Trong trng hs ngi s dng tng th phi i truyn dn lu hn. Thc t qu trnh lp gi l s kt hp ca hai phng php trn.

4.6.3.1 Lp biu phn chia theo thi gian

Khi b lp biu phn chia thi gian phn b cc tc gi, cn xt n hnng v tuyn. Thng thng cc dch v tc bit cao i hi t nng lng hn, v th phn chia theo thi gian c u im l E b/No thp hn. Ngoi ra thigian tr trung bnh trong phng php ny l ngn hn so vi phng php ph

Phin dch v gi

Cuc gi gi

Thi gianc Thi gian

Kch thc gi

Hnh 4.20. c trng ca mt phin dch v gi


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chia theo m.

Nhc im chnh ca phng php phn chia thi gian l :

- Thi gian truyn dn ngn trong khi vic thit lp v gii phng kt nihi thi gian di thm ch n vi khung.

- Vic s dng phn b theo thi gian b hn ch bi di tc cao do hncng sut ca MS ng ln.

- Phng php ny s dng cc tc bit cao v to ra lu lng dng ciu ny dn n s thay i cao cc mc nhiu so vi lp biu phn chia m.

4.6.3.2 Lp biu phn chia theo m

Trong lp biu phn chia theo m tt c ngi s dng c n nh mt kkhi h cn chng. Nu nhiu ngi s dng gi yu cu lu lng th tc phi thp hn lp biu theo thi gian.

Cc u im chnh ca phng php ny l :

- Trong lp biu phn chia theo m, vic thit lp v gii phng s gy ra t

tht dung lng hn do tc bit thp v thi gian truyn dn lu hn. Do tc bit thp vic phn b ti nguyn lp biu gi phn chia theo m i hi nhiu gian hn lp biu gi phn chia theo thi gian. iu ny cho php d bo mc nhiu.

- Lp biu phn chia theo m c th l tnh hoc ng. Trong lp biu tnh, bit c phn b duy tr c nh trong sut thi gian kt ni. Trong lp bng, tc bit c th thay i ph hp vi lu lng gi.

- Phng php lp biu ny i hi cc kh nng ca MS thp hn.

4.7 Kt lun chng

Trong chng ny gii thiu c cc k thut c s dng troWCDMA. Trn c s ngi ta tin hnh qui hoch mng WCDMA.


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Chng 5

QUY HOCH MNG W-CDMA

5.1 Gii thiu

Chng ny s trnh by qu trnh qui hoch mng W-CDMA v kt qu m phng tnh ton suy hao ng truyn, kch thc v dung lng knh,Qtrnh quy hoch mng v tuyn cho h thng thng tin di ng th h ba bao gcc bc sau : nh kch c, quy hoch lu lng v vng ph sng, ti u hmng.

Giai on nh kch c s a ra d tnh s i trm, s trm gc, cu hnh phn t gc v cc phn t mng khc trn c s cc yu cu ca nh khai trong vng. nh c phi thc hin c cc yu cu ca nh khai thc v v ph, dung lng v cht lng phc v. Vic quy hoch dung lng v vng

Cc yu cuvng ph

Yu cu dunglng

Kiu vng, mhnh truyn sngv tuyn

u voSuy hao ngtruyn cho php

Quy hoch dunglng v vng ph

Hin th hiu nngmng

Ti u ho

nh c - S b s trm gc- Cu hnh i trm.

- Chn i trm.- Chn cu hnh BS.- Cc thng s RRM.- Phn tch chtlng phc v

iu chnh thng sRRM

Kt qu o hiunng mng

u ra

Hnh 5.1. Qu trnh quy hoch mng v tuyn cho h thngthng tin di ng th h ba.


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phi c xem xt ng thi do dung lng v vng ph c quan h cht chnhau trong mng di ng. Khi mng i vo hot ng, c th tnh ton hiu nmng bng cc php o v cc kt qu o c s dng hin th v ti uhiu nng ca mng.

5.2 Tnh suy hao ng truyn cho php

xc nh vng ph cc i ca nh thit k phi tnh ton tn hao truyn cc i cho php m bo cng tn hiu ph hp bin gii cho lng ting chp thun trn 90% vng ph. Tn hao ng truyn cho php l hs gia cng sut pht x hiu dng ca my pht v cng tn hiu ti thiu

thit my thu cho cht lng ting chp thun. Cc thnh phn xc nh tn ng truyn c gi l qu nng lng ng truyn.

tnh tn hao cc i cho php ta s dng cng thc sau :

La = Pm Pmin + G b Lc L b Lh (5.1)

Vi :

Pmin = N0 + F b + (E b/N0)req + 10lgB (5.2)

Trong :La : Tn hao ng truyn cho php.

Pm : Cng sut pht x hiu dng ca MS.

Pmin : Cng tn hiu ti thiu yu cu.

G b : H s khuch i ca Anten pht BS.

Lc : Tn hao cp Anten thu BS.

L b : Tn hao c th.

Lh : Tn hao truy nhp ta nh.

B : Tc bit (Bps)

N0 : Tp m nn ca BS.


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F b : H s tp m my thu.

E b/N0 : d tr cn thit ca anten pht BS.

5.3 Xc nh kch thc Sau khi tnh c suy hao ng truyn cc i ta tnh c bn knh (

cc i tho mn yu cu truyn nhn thng tin da vo cc m hnh truyn sDo c im truyn sng khng n nh, nn cc m hnh truyn sng u matnh thc nghim. Di y ta xt hai m hnh truyn sng c s dng rng rm hnh Hata Okumura v Walfsch Ikegami.

5.3.1 M hnh Hata Okumura

Hu ht cc cng c truyn sng s dng mt dng bin i ca m hnh HM hnh Hata l quan h thc nghim c rt ra t bo co k thut ca Okumcho php s dng cc kt qu vo cc cng c tnh ton. Cc biu thc cdng trong m hnh Hata xc nh tn hao trung bnh :

Vng thnh ph

L p= 69,55+26,16.lgf c 13,28.lgh b a(hm) + (44,9-6,55.lgh b).lgR (dB) [6] (5.3)

Trong :

fc : Tn s hot ng (MHz).

L p : Tn hao cho php.

h b : cao anten trm gc (m).

a(hm) : H s hiu chnh cho cao anten di ng (dB)

R : Bn knh (km).

Di thng s s dng cho m hnh Hata l :

MHz f c 1500150

30 h b 200m


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H s hiu chnh (hm) c tnh nh sau:

i vi thnh ph ln:

a(hm) =8,29.(lg1,54hm)2 - 1,1 (dB) vi f c 200MHz (5.4)

a(hm) =3,2.(lg11,75hm)2 - 4,97 (dB) vi f c 400MHz (5.5)

i vi thnh ph nh v trung bnh :

a(hm) = (1,1.lgf c 0,7).hm (1,56.lgf c 0,8) (dB) (5.6)

Nh vy bn knh c tnh :

b

mbc p

hhah f L

Rlg.55,69,44

lg.28,13lg.26,2655,69lg (5.7)

Vng ngoi

Vi vng ngoi h s hiu chnh suy hao so vi vng thnh ph l :

Lno= L p - 2

4,528

lg2

c f (dB) (5.8)

Vng nng thn

Vi vng nng thn h s hiu chnh suy hao so vi vng thnh ph l :

Lnt= L p 4,78.(lgf c)2 +18,33(lgf c) - 40,49 (dB) (5.9)

5.3.2 M hnh Walfsch Ikegami

M hnh ny c s dng nh gi tn hao ng truyn mi tr

thnh ph cho h thng thng tin di ng t ong. M hnh ny cha cc phn ttn hao khng gian t do, nhiu x mi nh, tn hao tn x

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