Thuyet Minh Do an Tot Nghiep-2007

7/31/2019 Thuyet Minh Do an Tot Nghiep-2007

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MC LC

Cc t vit tt........................................................................................................ 4

M u .......................................................................................................................11

Chng 1 TNG QUAN V THNG TIN DI NG S.

1.1. Gii thiu .....................................................................................................13

1.2. H thng thng tin di dng th h 1...........................................................14

1.3. H thng thng tin di dng th h 2..................................................................15

1.3.1 a truy cp phn chia theo thi gian TDMA...........................................15

1.3.2 a truy cp phn chia theo m CDMA....................................................16

1.4 H thng thng tin di ng th h ba..........................................................17

1.5 Kt lun chng.................................................................................................18

Chng 2 GII THIU H THNG THNG TIN DI NG GSM.

2.1. Gii thiu lch s pht trin ..............................................................................19

2.2. Cu trc mng GSM..........................................................................................20

2.2.1. Trm di ng..................................................................................................21

2.2.2. H thng con trm gc....................................................................................222.2.3. H thng mng con.........................................................................................22

2.2.4 a truy cp trong GSM...................................................................................23

2.2.5 Cc th tc thng tin.................................................................................24

2.2.5.1 ng nhp thit b vo mng.......................................................................24

2.2.5.2 Chuyn vng................................................................................................25

2.2.5.3 Thc hin cuc gi ......................................................................................25

2.2.5.3.1 Cuc gi t thit b di ng vo in thoi c nh..................................25

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2.2.5.3.2 Cuc gi t in thoi c nh n thit b di ng..................................26

2.2.5.3.3 Cuc gi t thit b di ng n thit b di ng........................................27

2.2.5.3.4 Kt thc cuc gi.................................................................................27

2.3 S pht trin mng GSM ln 3G................................................................28

2.3.1 H thng GSM s c nng cp tng bc ln th h ba.....................28

2.3.2 Cc gii php nng cp............................................................................28

2.4 Kt lun chng..................................................................................................30

Chng 3 CNG NGH DI NG TH H BA W-CDMA.

3.1 . Gii thiu cng ngh W-CDMA...................................................................32

3.2 . Cu trc mng W-CDMA............................................................................34

3.2.1 Mng truy nhp v tuyn..........................................................................36

3.2.1.1 c trng ca UTRAN...........................................................................37

3.2.1.2 B iu khin mng v tuyn UTRAN..................................................37

3.2.1.3 Node B.....................................................................................................38

3.2.2 Giao din v tuyn.....................................................................................38

3.2.2.1. Giao din UTRAN CN, IU .......................................................................393.2.2.2. Giao din RNC RNC, IUr...........................................................................40

3.2.2.3. Giao din RNC Node B, IUb ......................................................................41

3.3 Kt lun chng ..........................................................................................41

Chng 4 CC GII PHP K THUT TRONG W-CDMA.

4.1 Gii thiu .......................................................................................................43

4.2 M ha ...........................................................................................................43

4.2.1 M vng...........................................................................................................43

4.2.2 M xon .......................................................................................................45

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4.2.3. M Turbo....................................................................................................45

4.3 iu ch BIT/SK v QPSK..........................................................................45

4.3.1 iu ch BIT/SK.........................................................................................45

4.3.2 iu ch QPSK...........................................................................................45

4.4 Tri ph trong W-CDMA.............................................................................48

4.4.1 Gii thiu.....................................................................................................48

4.4.2 Nguyn l tri ph DSSS............................................................................50

4.4.3 M tri ph.................................................................................................51

4.4.4 Cc hm trc giao......................................................................................53

4.5 Cu trc phn knh ca WCDMA...............................................................53

4.5.1 Knh vt l..................................................................................................54

4.5.1.1 Knh vt l ring ng ln....................................................................54

4.5.1.2 Knh vt l chung ng ln.........................................................................56

4.5.1.3 Knh vt l ring ng xung (DPCH).......................................................60

4.5.1.4 Knh vt l chung ng xung....................................................................60

4.5.2. Knh truyn ti..................................................................................................654.5.2.1 Knh truyn ti ring.....................................................................................65

4.5.2.2. Knh truyn ti chung....................................................................................65

4.5.2.3 Sp xp knh truyn ti ln knh vt l.........................................................67

4.6 Truy nhp gi trong W-CDMA....................................................................67

4.6.1 Tng quan v truy nhp gi trong W-CDMA.........................................68

4.6.2. Lu lng s liu gi.....................................................................................68

4.6.3 Cc phng php lp biu gi..................................................................69

4.6.3.1 Lp biu phn chia theo thi gian................................................................69

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4.6.3.2. Lp biu phn chia theo m.........................................................................70

4.7. Kt lun chng .................................................................................................70

Chng 5 QUY HOCH MNG W-CDMA.

5.1 Gii thiu........................................................................................................71

5.2 Tnh suy hao ng truyn cho php...........................................................72

5.3. Xc nh kch thc .........................................................................................73

5.3.1. M hnh Hata Okumura.........................................................................73

5.3.2. M hnh Walfsch Ikegami.......................................................................74

5.4. Tnh ton dung lng v vng ph......................................................................76

5.5 Chng trnh m phng v tnh ton...................................................................78

5.5.1 Lu tnh ton................................................................................................79

5.5.2 Kt qu chng trnh........................................................................................80

5.6. Kt lun chng..................................................................................................82

Kt lun.......................................................................................................................83

Ti liu tham kho......................................................................................................84

Ph lc .......................................................................................................................85

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Cc t vit tt

B ng tra c u t vi t t t B ngtra c u t vi t t t

ACCH Associated Control Channels

Knh iu khin lin kt.

AI Acquisition Indicator

Ch th bt.

AMPS Advanced Mobile Phone System

H thng in thoi di ng tin tin.

ARQ Automatic Repeat Request

Yu cu lp li t ng.AS Access Stratum

Tng truy nhp.

BCCH Broadcast Control Channel

Knh qung b iu khin.

BCH Broadcast Channel

Knh qung b.

BER Bit Error RatioT s bit li.

BSC Base Station Controler

B iu khin trm gc.

BSS Base Station Subsystem

Phn h trm gc.

BTS Base Tranceiver Station

Trm 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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Cc t vit tt

C/I Carrier to Interference ratio

T s sng mang trn nhiu.

CCCH Common Control Chanel

Knh iu khin chung.

CCPCH Common Control Physical Chanel

Knh vt l iu khin chung.

CPCC Common Power Control Chanel

Knh iu khin cng sut chung.

CPCH Common Packet Chanel.

Knh gi chung.

CPICH Common Pilot Chanel

Knh hoa tiu chung.

CR Chip Rate

Tc chip (tng ng vi tc tri ph ca knh).

CS Circuit Switch

Chuyn 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 Chanel

Knh s liu vt l ring.

DTCH Dedicated Traffic Chanel

Knh lu lng ring.

DTE Data Terminal Equipment

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Cc t vit tt

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 dn

ETSI 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 ChannelKnh hiu chnh tn s.

FDD Frequency Division Duplex

Ghp knh song cng phn chia theo tn s.

FDMA Frequence Division Multiple Access

a truy cp phn chia theo tn s

FDCCH Forward Dedicated Control Chanel

Knh 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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Cc t vit tt

GPS Global Position System

H thng nh v ton cu.

GPRS General Packet Radio Services

Dch 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 54Tiu chun thng tin di ng TDMA ca M (do AT&T xut).

IS-136 Interim Standard 136

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

IS-95A Interim Standard 95A

Tiu 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 mng

LAC Link Access Control

iu khin truy nhp lin kt.

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Cc t vit tt

LAI Location Area Indentify

Nhn dng vng v tr.

LLC Logical Link Control

iu khin lin kt logic.

LR Location Registration

ng k v tr.

ME Mobile Equipment

Thit b di ng.

MS Mobile Station

Trm di ng.

MTP Message Transfer Part

Phn truyn bn tin.

MSC Mobile Service Switching Center

Tng i di ng.

NAS Non-Access Stratum

Tng khng truy nhp.Node B L nt logic kt cui giao din IuB vi RNC.

NSS Network and Switching Subsystem

H thng chuyn mch

ODMA Opportunity Driven Multiplex Access

a truy cp theo c hi.

OM Operation and Management

Khai 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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Cc t vit tt

PCH Paging Channel

Knh nhn tin.

PCPCH Physical Common Packet Chanel

Knh gi chung vt l.

PCS Personal Communication Services

Dch 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 Channel

Knh truy cp ngu nhin.

RRC Radio Resource Control

iu 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 gian

TACH Traffic and Associated Channel

Lnh lu lng v lin kt.

TCH Traffic Channel

Knh lu lng.

TDMA Time Division Multiple Access

a truy cp phn chia theo thi gian

TDD Time Division Duplex

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Cc t vit tt

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 System

VA 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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12/92

Li ni uLi ni u----------@----------

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

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 hn, h 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 dng c tnhnng ca h thng 2G khi chuyn hng sang 3G cn thit c mt gii 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 chuyn mch gi), tip

theo l EDGE (tiu chun 3G trn bng tn GSM v h tr d liu ln ti 384kbit)

v UMTS (cng ngh bng thng hp GSM s dng truyn dn CDMA), 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 v nhiu 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, truy cp Internet,

truyn ti d liu dung lng ln, nghe nhc v xem video cht lng cao, 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 cucsng ring t v cng vic ca chng ta.

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).

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Ngy 10/3/2005, B BCVT tin hnh nghim thu ti xy dng tiu

chun thit b u cui thng tin di ng WCDMA (UTRA-FDD) m s 49-04-

KTKT-TC dnh cho cng ngh 3G. Theo nh gi ca cc thnh vin phn bin, vic

xy dng v hon thnh cng trnh l mt vic lm cn thit, c ngha v c

bit l kh thi trong giai on hin nay, khi nhu cu pht trin ln 3G l mt xu

hng tt yu Vit Nam, nht l cc nh di ng mng GSM (Theo bo in t

VietNamNet).

Xut pht t tng mun tm hiu cng ngh W-CDMA v mng W-

CDMA em thc hin n: Cng ngh W-CDMA v qui hoch mng W-CDMA.

n ny em trnh by 5 chng, vi ni dung chnh l chng3, chng 4,

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 em

hon 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

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 qua nhiu

th h.Th h khng dy th 1 l th h thng tin tng t s dng cng ngh a

truy cp phn chia phn chia theo tn s (FDMA).Th h th 2 s dng k thut s

vi cng ngh a truy cp phn chia theo thi gian (TDMA) v phn chia theo m

(CDMA).Th h th 3 ra i nh gi s nhy vt nhanh chng v c dung lng v

ng dng so vi cc th h trc , v c kh nng cung cp cc dch v a phng

tin gi l th h ang c trin khai mt s quc gia trn th gii.

Qu trnh pht trin ca cc h thng thng tin di ng trn th gii c th

hin s pht trin ca h thng in thoi t ong (CMTS : Cellular Mobile Telephone

System) v nhn tin (PS : Paging System) tin ti mt h thng chung ton cu trong

tng lai.

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

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Hnh 1.1: H thng in thoi di ng

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 tn

s . H thng di ng th h 1 s dng phng php a truy cp phn chia theo tn

s (FDMA) v ch h tr cc dch v thoi tng t v s dng k thut iu ch

tng t mang d liu thoi ca mi ngi s dng .Vi FDMA , khch hng

c cp pht mt knh trong tp hp c trt t cc knh trong lnh vc tn s. S

bo hiu ca h thng FDMA kh phc tp, khi MS bt ngun hot ng th n

d sng tm n knh iu khin dnh ring cho n. Nh knh ny, MS nhn c d

liu bo hiu gm cc lnh v knh tn s dnh ring cho lu lng ngi dng .

Trong trng hp nu s thu bao nhiu hn so vi cc knh tn s c th, 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 dng

c di tn gn cho h m khng b trng nh vic chia ph tn ra thnh nhiu

on .Ph tn s quy nh cho lin lc di dng c chia thnh 2N di tn s k tip,

v c cch nhau bng mt di tn phng v. Mi di tn s c gn cho mt knh

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lin lc. N di k tip dnh cho lin lc hng ln, sau mt di tn 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 tin

(Advanced Mobile phone System - AMPS).

H thng thng tin di ng th h 1 s dng phng php a truy cpn gin. Tuy nhin h thng khng tho mn nhu cu ngy cng tng ca

ngi dng v c dung lng v tc . V cc khuyt im trn m ngui ta

a ra h thng thng tin di dng th h 2 u im hn th h 1 v c dung

lng v cc dch v c cung cp.

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 chtlng, h thng thng tin di ng th h 2 c a ra p ng kp thi s

lng 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 chng

s 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 v

trc thi gian c chia thnh nhiu khong thi gian nh dnh cho nhiu ngi

s dng sao cho khng c s chng cho.Ph quy nh cho lin lc di ng

c chia thnh cc di tn lin lc, mi di tn lin lc ny dng chung cho N

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knh lin lc, mi knh lin lc l mt khe thi gian trong chu k mt khung.

Cc thu bao khc dng chung knh nh ci xen thi gian, mi thu bao c

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, trong

mt bng tn c s dng truyn tn hiu t trm gc n cc my

di ng v mt bng tn c s dng truyn tn hiu t my di ng n

trm gc. Vic phn chia tn nh vy cho php cc my thu v my pht c th

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 cu

(Global System for Mobile Communications - GSM).

My in thoi di ng k thut s TDMA phc tp hn k thut FDMA.

H thng x l s i vi tn hiu trong MS tng t c kh nng x l khng

qu 106 lnh trong 01 giy, cn trong MS s TDMA phi c kh nng 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 nn

nhiu ngi s dng c th chim cng knh v tuyn ng thi tin hnh cc

cuc gi m khng s gy nhiu ln nhau. Nhng ngi s dng ni trnc phn bit vi nhau nh dng mt m c trng khng trng vi bt k

ai. Knh v tuyn CDMA c dng li mi cell trong ton mng, v nhng

knh ny cng c phn bit nhau nh m tri ph gi ngu nhin (Pseudo

Noise - PN).

c im ca CDMA:

-Di tn tn hiu rng hng MHz.

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-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 b

truyn dn v tuyn n gin, vic thay i k hoch tn s khng cn vn

, 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 nhng

ci tin ang c thc hin trong lnh vc truyn thng khng dy cho in thoi vd liu thng qua bt k chun no trong nhng chun hin nay. u tin l tng tc

bit truyn t 9.5Kbps ln 2Mbps. Khi s lng thit b cm tay c thit k

truy cp Internet gia tng, yu cu t ra l phi c c cng ngh truyn thng

khng dy nhanh hn v cht lng hn. Cng ngh ny s nng cao cht lng

thoi, v dch v d liu s h tr vic gi ni dung video v multimedia 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 h

2.5G sang th h 3 (3 - Generation). p ng nhu cu ngy cng tng v cc dch

v thng tin di ng, ngay t u nhng nm u ca thp k 90 ngi ta tin

hnh nghin cu hoch nh h thng thng tin di ng th h ba. ITU-R ang tin

hnh 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 UMTS

(Universal Mobile Telecommunnication System). H thng mi ny s lm vic ditn 2GHz. N s cung cp nhiu loi hnh dch v bao gm cc dch v thoi v s

liu tc cao, video v truyn thanh. Tc cc i ca ngi s dng c th ln

n 2Mbps. Ngi ta cng ang tin hnh nghin cu cc h thng v tuyn th h

th t c tc ln n 32Mbps.

H thng thng tin di ng th h ba c xy dng trn c s IMT 2000 vi

cc tiu ch sau :

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- S dng di tn quy nh quc t 2GHz vi ng ln c di tn 1885-

2025MHz v ng xung c di tn 2110-2200MHz.

- L h thng thng tin di ng ton cu cho cc loi hnh thng tin v tuyn,

tch hp cc mng thng tin hu tuyn v v tuyn, ng thi tng tc vi mi loi

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 Vitual

Home Environment) trn c s mng thng minh, di ng c nhn v chuyn mch

ton cu; m bo chuyn mng quc t; m bo cc dch v a phng tin ng

thi 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 nay

l : GSM, cdmaOne (IS-95), TDMA (IS-136), PDC. Trong qu trnh thit k h thng

thng tin di ng th h ba, cc h thng th h hai c c quan chun ha ca tng

vng xem xt a ra cc xut tng ng thch hp vi mi vng.

1.5 Kt lun chng

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

tin di ng. Vi nhu cu khng ngng tng ln ca ngi s dng c v cht lng

v s lng, nhu cu trao i thng tin trnh cao v a dng s pht trin y l

tt yu.Hin nay cng ngh 3G ang c ng dng mt cch mnh m cc nc

trn th gii vi cc dch v tin ch nh in thoi truyn hnh, truy nhp internet,

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Trang 20


21/92

Gii thiu h thng thng tin di ng GSM

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 thng tin

di ng GSM, kin trc mng GSM , phng php a truy cp trong GSM , cc th

tc thng tin ca thu bao s dng trong mng v s cn thit phi nng cp mng

GSM ln th h 3G.

Lch s hnh thnh GSM bt u t mt xut vo nm 1982 ca NordicTelecom v Netherlands ti CEPT (Conference of European Post and

Telecommunication) pht trin mt chun t bo s mi p ng vi nhu cu

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 vin s

dng GSM cho php lin lc di ng trong bng tn 900MHz. Vin tiu chun vin

thng Chu u (ETSI) nh ngha GSM khi quc t chp nhn tiu chun h thng

in thoi t bo s.

Li xut c kt qu vo thng 9 nm 1987, khi 13 nh iu hnh v qun l

ca nhm c vn CEPT GSM tha thun k hip nh GSM MoU Club, vi ngy

khi u l 1 thng 7 nm 1991.

GSM l t vit tt ca Global System for Mobile Communications (h thng

thng 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 tch

hp v ton din, c pht trin u tin Chu u v nhanh chng pht trin

trn ton th gii. Mng c thit k ph hp vi h thng ISDN v cc dch v m

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 935-960

MHz, 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 thng thng

mi u tin c khi u vo gia nm 1992. T chc MoU (Memorandum of

Understanding) thnh lp bi nh iu hnh v qun l GSM c cp php u tin,

lc c 13 hip nh c k kt v n nay c 191 thnh vin khp th gii.

T chc MoU c quyn lc ti a, c quyn nh chun GSM.

2.2. Cu trc mng GSM

Mng GSM gm nhiu khi chc nng khc nhau. Hnh di cho thy cch b

tr ca mng GSM tng qut. Mng GSM c th chia thnh ba phn chnh. Trm di

ng (Mobile Station_MS) do thu bao gi. H thng con trm gc (BaseStation

Subsystem_BSS) iu khin lin kt vi trm di ng. H thng mng con (Network

Subsystem_NS) l phn chnh ca trung tm chuyn mch dch v di ng MSC

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(Mobile services Switching Center), thc hin chuyn mch cuc gi gia nhng

ngi s dng in thoi di ng, v gia di ng vi thu bao mng c nh. MSC

x l cc hot ng qun l di ng. Trong hnh khng c trnh by trung tm duy tr

v iu hnh (Operations and Maintenance Center_OMS), gim st iu hnh v c

cu ca mng. Trm di ng v h thng con trm gc thng tin dng giao tip Um,

cn c gi l giao tip khng trung hay lin kt v tuyn. H thng con trm gc

lin lc vi trung tm chuyn mch dch v di ng dng giao 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 mt

card thng minh gi l module nhn dng thu bao (Subscriber Identity

Module_SIM). SIM cung cp thng tin c nhn di ng, v th ngi s dng truy

cp vo cc dch v thu bao khng ph thuc vo loi thit b u cui. Bng cch

gn SIM vo u cui GSM, ngi s dng c th nhn, gi v nhn cc dch v thu

bao khc trn thit b u cui ny.

Thit b di ng c nhn dng duy nht bng s nhn dng thit b di ng

quc t (International Mobile Equipment Identity_IMEI). SIM card cha s nhn

dng thu bao di ng quc t (International Mobile Subscriber Identity_IMSI) s

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dng nhn dng thu bao trong h thng, dng xc nh ch quyn v thng tin

khc. S IMEI v IMSI c lp nhau. SIM card c th c bo v chng li vic

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 gc

iu khin (BSC). Hai h thng ny lin kt dng giao tip Abis chun ho, cho

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 cc

giao thc lin kt v tuyn vi trm di ng. Trong mt thnh ph ln, c nhiu kh

nng trin khai nhiu BTS, do yu cu BTS phi chnh xc, tin cy, di chuyn

c v gi thnh thp.

Trm gc iu khin ti nguyn v tuyn ca mt hoc nhiu BTS. Trm iu

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 nh

mt nt chuyn mch bnh thng ca PSTN hoc ISDN, v cung cp tt c cc chc

nng cn c iu khin mt thu bao di ng, nh ng k, xc nhn, cp nht ta

, trao tay, v nh tuyn cuc gi cho mt thu bao lin lc di ng. Nhng dch

v ny c cung cp chung vi nhiu b phn chc nng khc, to nn h thng

mng con. MSC cung cp kt ni n mng c nh (nh PSTN hoc ISDN). Bohiu gia cc b phn chc nng trong h thng mng con l h thng bo hiu s 7

(SS7) s dng cho bo hiu trung k trong mng ISDN v m rng s dng trong

mng cng cng hin ti.

B ghi nh v thng tr (HLR) v b ghi nh v tm tr (VLR) cng vi

MSC cung cp nh tuyn cuc gi v kh nng lin lc di ng ca GSM. HLR

cha tt c thng tin qun tr ca mi thu bao ng k trong mng GSM tng

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ng, cng vi v tr hin ti ca di ng. V tr ca di ng thng di dng a

ch bo hiu ca VLR cha trm di ng.

B ghi nh v tm tr (VLR) cha thng tin qun tr c chn t HLR, cn

thit cho iu khin cuc gi v cung cp cc dch v thu bao, cho mi thu bao

hin ti nm trong vng a l iu khin bi VLR. Mc d mi b phn chc nng

chung c th c thc hin c lp nhng tt c cc nh sn xut thit b chuyn

mch cho n nay u sn xut VLR vi MSC, v th vng a l iu khin bi

MSC s tng ng vi iu khin bi VLR , do n gin ha bo hiu cn

thit. Lu rng MSC khng cha thng tin cc trm di ng thng tin ny lu trtrong cc thanh ghi v tr.

C hai b ghi khc s dng cho mc ch xc nhn v bo mt. B ghi nhn

thc thit b (EIR) l mt c s d liu cha mt danh sch tt c cc thit b di ng

hp l trn mng, mi trm di ng c xc nhn bng s nhn dng thit b di

ng quc t (IMEI). S IMEI b nh du l khng hp l nu c thng bo mt

cp hoc khng c chp thun. Trung tm nhn thc AuC l c s d liu c

bo v cha bn sao kha m trong SIM card ca thu bao, s dng nhn thc 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 tn

935 960MHz c s dng cho ng ln v 890 915MHz cho ng xung

(GSM 900). Di bng thng tn mt knh l 200KHz, di tn bo v bin cng

rng 200KHz nn ta c tng s knh trong FDMA l 124. Mt di thng TDMA l

mt khung c tm khe thi gian, mt khung ko di trong 4.616ms. Khung ng ln

tr 3 khe thi gian so vi khung ng xung, nh tr ny m MS c c th s dng

mt khe thi gian c cng s th t c ng ln ln ng xung truyn tin

bn song cng.

Cc knh tn s c s dng GSM nm trong dy tn s quy nh 900Mhz

xc nh theo cng thc sau:

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

FU = 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 s

knh tn v tuyn. Ta thy tng s knh tn s c th t chc cho mng GSM l 124

knh. cho cc knh ln cn khng gy nhiu cho nhau mi BTS ph mt ca

mng phi s dng cc tn s cch xa nhau v cc ch c s dng li tn s

khong cch cho php.

Truyn dn v tuyn GSM c chia thnh cc cm (BURST) cha hng

trm bit c iu ch. Mi cm c pht i trong mt khe thi gian 577s

trong mt knh tn s c rng 200 Khz ni trn. Mi mt knh tn s cho php t

chc cc khung thm nhp theo thi gian, mi khung bao gm 8 khe thi gian t 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 tng

s 416 knh. Sau n chn mt knh mnh nht v kha knh ny. Sau 60s qa

trnh 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 sang ktni vi knh c tn hiu mnh nht.

2.2.5.2 Chuyn vng.

V GSM l mt chun chung nn thu bao c th dng in thoi h GSM ti

hu ht cc mng GSM trn th gii. Trong khi di chuyn thit b lin tc d knh

lun duy tr tn hiu vi trm l mnh nht. Khi tm thy trm c tn hiu mnh hn,

thit b s t ng chuyn sang trm mi, nu trm mi nm trong vng ph khc

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thit b s bo cho mng bit v tr mi ca mnh.

Ring trong ch chuyn vng quc t hoc chuyn vng gia mng ca hai

nh khai thc dch v khc nhau th qu trnh cp nht v tr i hi phi c s chp

thun v h tr t cp nh khai thc dch v.

2.2.5.3Thc 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 thi tch

cc cho thit b vo VLR, xc thc, m ha, nhn dng thit b, gi s c gi cho

mng, kim tra xem thu bao c ng k dch v cm gi ra u c thc hin trong

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.

Trang

GSM/PLMN PSTN

1

2

3

4 4

12

3

4

BSC/TRC MSC/VLR

Thit bu cui

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

5 6

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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 thit b

khng c bit chnh xc. Chnh v th trc khi kt ni, mng phi thc hin cng

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 PSTN. Mng

s phn tch v nu pht hin ra t kha gi mng di ng, mng PSTN s kt ni 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 trong HLR

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 cho thit

b. Nu c ng k dch v chuyn tip cuc gi n, cuc gi s c tr v GMSC

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 qun l

LAI ny.

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8. BSC pht thng ip ra ton b vng cc thuc LAI.9. Khi nhn c thng ip thit b s gi yu cu ngc li.

10. BSC cung cp mt khung thng ip cha thng tin.

11. Phn tch thng ip ca BSC gi n tin hnh th tc bt trng thi ca

thit b ln tch cc, xc nhn, m ha, nhn din thit b.

12. MSC/VLR iu khin BSC xc lp mt knh ri, chung. Nu thit b di

ng chp nhn tr li, kt ni c thit lp.

2.2.5.3.3 Cuc gi t thit b di ng n thit b di ng.

Qu trnh din ra tng t nh gi t in thoi c nh n thit b di ng, ch

khc im giao tip vi mng PSTN ca in thoi c nh s c thay th bng

MSC/VLR khc.

2.2.5.3.4 Kt thc cuc gi.

Khi MS tt my pht, mt tn hiu c bit (tn hiu n tone) c pht n

Trang

Hnh 2.4. Gi t in thoi c nh n thit b di ng

GSM/PLMN PSTN

HLR GMSC

BSC/TRC

MSC/VLR

Tng i ni

b

1 125

5 6

4

7 11

8

8

89

1011

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cc trm gc v hai bn cng gii phng cuc gi. MS tip tc kim tra tm gi 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 phm vi

ton cu ng thi m bo tnh kinh t, h thng GSM s c nng cp tng bc

ln th h ba. Thng tin di ng th h ba c kh nng cung cp dch v truyn thng

multimedia bng rng trn phm vi ton cu vi tc cao ng thi cho php ngi

dng s dng nhiu loi dch v a dng. Vic nng cp GSM ln 3G c thc hin

theo cc tiu ch sau :

- L mng bng rng v c kh nng truyn thng a phng tin trn phm vi

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

- C kh nng cung cp rng bng thng theo yu cu nhm h tr mt di

rng cc dch v t bn tin nhn tc thp thng qua thoi n tc d liu cao

khi truyn video hoc truyn file. m bo cc kt ni chuyn mch cho thoi, cc

dch v video v kh nng chuyn mch gi cho dch v s liu. Ngoi ra n cn h

tr ng truyn v tuyn khng i xng tng hiu sut s dng mng (chng

hn 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 dch

v mi nh nh s c nhn ton cu v in thoi v tinh. Cc tnh nng ny s cho

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 pht

trin lin tc ca thng tin di ng. Tng thch vi cc dch v trong ni b IMT-

2000 v vi cc mng vin thng c nh nh PSTN/ISDN. C cu trc m cho php

a vo d dng cc tin b cng ngh, cc ng dng khc nhau cng nh kh 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, thay

th bng h thng thng tin di ng th h ba; hai l nng cp GSM ln GPRS v tip

n l EDGE nhm tn dng c c s mng GSM v c thi gian chun b tin

ln h thng 3G W-CDMA. Gii php th hai l mt gii php c tnh kh thi v tnh

kinh t cao nn y l gii php c a chung nhng nc ang pht trin nh

nc ta.

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

hn, c th h tr hai ch dch v s liu l ch chuyn mch knh (CS :

Circuit Switched) v ch chuyn mch gi (PS : Packet Switched). thc hin

kt ni vo mng IP, giai on ny c th s dng giao thc ng dng v tuyn

(WAP : Wireless Application Protocol). WAP cha cc tiu chun h tr truy cp

internet t trm di ng. H thng WAP phi c cng WAP v chc nng kt ni

mng.

Trang

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 ngh s

liu chuyn mch knh tc cao (HSCSD : High Speed Circuit Switched Data) v

dch v v tuyn gi chung (GPRS : General Packet Radio Protocol Services). GPRS

s h tr WAP c tc thu v pht s liu ln n 171.2Kbps. Mt u im quan

trng ca GPRS na l thu bao khng b tnh cc nh trong h thng chuyn mch

knh m cc ph c tnh trn c s lu lng d liu s dng thay v thi giantruy cp.

Dch v GPRS to ra tc cao ch yu nh vo s kt hp cc khe thi gian,

tuy nhin k thut ny vn da vo phng thc iu ch nguyn thu GMSK nn

hn ch tc truyn. Bc nng cp tip theo l thay i k thut iu ch kt hp

vi ghp khe thi gian ta s c tc truyn d liu cao hn, chnh l cng ngh

EDGE.EDGE vn da vo cng ngh chuyn mch knh v chuyn mch gi vi tc

ti a t c l 384Kbps nn s kh khn trong vic h tr cc ng dng i

hi vic chuyn mch linh ng v tc truyn d liu ln hn. Lc ny s thc

hin 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 cn

Trang

GSM

HSCSD

WCDMAData Speed

171.2Kbps

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 a cc

dch v nh Internet, truyn hnh...

Vi cng ngh 3G, cc nh khai thc mng c th cung cp nhiu dch v s

liu cho cc khch hng ca mnh, cc dch v hp dn ny lm cho cuc sng ca h

d dng hn. Nh , cc nh khai thc mng c th tng doanh thu trung bnh trn

mt thu bao. Ngoi ra, 3G cn to kh nng cho cc nh khai thc cung cp cc dch

v c bit dnh ring cho cc thu bao ca mnh c c s trung thnh ca

khch hng .

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Cng ngh di ng th h ba W-CDMA

Chng3

CNG NGH DI NG TH H BA W-CDMA3.1 Gii thiu cng ngh W-CDMA

Chng ny s gii thiu v cng ngh W-CDMA, cu trc mng W-CDMA,

mng truy nhp v tuyn UTRAN, cc giao din v tuyn v c trng ring ca

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 ccdch v a phng tin tc cao nh video, truy cp Internet, hi tho hnh...

WCDMA 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 cch

dng k thut CDMA hot ng bng tn rng thay th cho TDMA. Trong cc

cng ngh thng tin di ng th h ba th W-CDMA nhn c s ng h ln nht

nh vo tnh linh hot ca lp vt l trong vic h tr cc kiu dch v khc nhau cbit 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 TDD

pht lin tc cng nh khng to iu kin cho cc k thut chng nhiu cc mi

trng lm vic khc nhau.

H thng thng tin di ng th h ba W-CDMA c th cung cp cc dch v vi

tc bit ln n 2MBit/s. Bao gm nhiu kiu truyn dn nh truyn dn i xng

v khng i xng, thng tin im n im v thng tin a im. Vi kh nng ,

cc h thng thng tin di ng th h ba c th cung cp d dng cc dch v mi nh

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: in thoi thy hnh, ti d liu nhanh, ngoi ra n cn cung cp cc dch v a

phng tin khc.

Cc nh khai thc c th cung cp rt nhiu dch v i vi khch hng, t cc

dch v in thoi khc nhau vi nhiu dch v b sung cng nh cc dch v khng

lin quan n cuc gi nh th in t, FPT

Cng trnh nghin cu ca cc nc chu u cho W-CDMA bt u t nCODIT (Code Division Multiplex Testbed : Phng th nghim a truy cp theo m)

v FRAMES (Future Radio Multiplex Access Scheme : K thut a truy cp v tuyn

trong tng lai) t u thp nin 90. Cc d n ny tin hnh th nghim cc h

thng W-CDMA nh gi cht lng ng truyn.

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 di ng

Trang

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

FTP

inthoi

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 vphn phithng tin

Tin tc

D bothi tit

Thng tinlu lng

Thng tinngh ngi

Truynhnh ding

Truyn

thanh ding

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 ba

35


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phi tri qua giai on 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 GPRS v Enhanced Data

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 nng

c th chia cu trc mng W-CDMA ra lm hai phn : mng li (CN) v mng truy

nhp v tuyn (UTRAN), trong mng li s dng ton b cu trc phn cng ca

mng GPRS cn mng truy nhp v tuyn l phn nng cp ca W-CDMA. Ngoi ra

hon thin h thng, trong W-CDMA cn c thit b ngi s dng (UE) thchin giao din ngi s dng vi h thng. T quan im chun ha, c UE v

UTRAN u bao gm nhng giao thc mi c thit k da trn cng ngh v

tuyn W-CDMA, tri li mng li c nh ngha hon ton da trn GSM. iu

ny cho php h thng W-CDMA pht trin mang tnh ton cu trn c s cng ngh

GSM.

UE (User Equipment)

Trang

PLMN,PSTNISDN

Internet

Ccmngngoi

MSC/VLR GMSC

GGSNSGSN

HLR

CN

RNC

Node B

Node B

RNC

Node B

Node B

IUb

IUr

UTRAN

IU

USIM

USIM

CU

UE

UU

Hnh 3.2. Cu trc ca UMTS

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Thit b ngi s dng thc hin chc nng giao tip ngi s dng vi h

thng. UE 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) : L mt th thng minh cha

thng tin nhn dng ca thu bao, n thc hin cc thut ton nhn thc, lu gi cc

kha 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 n

truy nhp v tuyn. UTRAN gm hai phn t :

- Nt B : Thc hin chuyn i dng s liu gia cc giao din I ub v Uu. N

cng tham gia qun l ti nguyn v tuyn.

- B iu khin mng v tuyn RNC: C chc nng s hu v iu khin cc ti

nguyn v tuyn trong vng (cc nt B c kt ni vi n). RNC cn l im truy

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 gi thng

tin chnh v l lch dch v ca ngi s dng. Cc thng tin ny bao gm : Thng tin

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

dch v b sung nh : trng thi chuyn hng cuc gi, s ln chuyn hng 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 mch knh

cho UE ti v tr ca n. MSC c chc nng s dng cc giao dch chuyn mch

knh. VLR c chc nng lu gi bn sao v l lch ngi s dng cng nh v tr

chnh xc ca UE trong h thng ang phc v.

- GMSC (Gateway MSC) : Chuyn mch kt ni vi mng ngoi.

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- SGSN (Serving GPRS) : C chc nng nh MSC/VLR nhng c s dng

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 ny

tun 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 ca h

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 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 : Giao din cho php kt ni mt nt B vi mt RNC. I Ub c

tiu 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 Network

Subsystem). Mt RNS gm mt b iu khin mng v tuyn RNC v cc node B.

Cc RNC c kt ni vi nhau bng giao din Iur v kt ni vi node B bng giao

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 cc

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 cc

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 chuyn

mch gi bng cch s dng giao thc v tuyn duy nht kt ni t UTRAN n

c 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 ca

UTRAN. RNC kt ni vi CN (thng thng l vi mt MSC v mt SGSN) qua

giao din v tuyn Iu. RNC iu khin node B chu trch nhim iu khin ti v

trnh tc ngn cho cc ca mnh. Khi mt MS UTRAN s dng nhiu ti nguyn v

Trang

Node BNode B

Node BNode B

RNCRNC

Node BNode B

Node BNode B

RNCRNC

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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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 c

ng ni Iu truyn s liu ngi s dng v bo hiu RANAP (phn ng dng

mng truy nhp v tuyn) tng ng t mng li. SRNC cng l kt cui bo hiu

iu khin ti nguyn v tuyn. N thc hin x l s liu truyn t lp kt ni s

liu ti cc ti nguyn v tuyn. SRNC cng l CRNC ca mt node B no c

s dng MS kt ni vi UTRAN.

- RNC tri (Drif RNC) : DRNC l mt RNC bt k khc vi SRNC iu

khin cc c MS s dng. Khi cn DRNC c th thc hin kt hp v phn tpv m. DRNC khng thc hin x l s liu trong lp kt ni s liu m ch nh

tuyn s liu gia cc giao din IUb v IUr. Mt UE c th khng c hoc c mt hay

nhiu DRNC.

3.2.1.3 Node B

Chc nng chnh ca node B l thc hin x l trn lp vt l ca giao din v

tuyn nh m ha knh, an xen, thch ng tc , tri phN cng thc hin phnkhai thc qun l ti nguyn v tuyn nh iu khin cng sut vng trong. V 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 t

mng m ch nh ngha giao din gia cc phn t logic. Cu trc giao din c

xy dng trn nguyn tc l cc lp v cc phn cao c lp logic vi nhau, iu nycho php thay i mt phn ca cu trc giao thc trong khi vn gi nguyn cc 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 c

hai kiu : Iu CS kt ni UTRAN vi CN chuyn mch knh v Iu PS kt ni

UTRAN 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 tuyn,

cp quang hay cp ng. C th la chn cc cng ngh truyn dn khc nhau nh

SONET, STM-1 hay E1 thc hin lp vt l.

- Ngn xp giao thc pha iu khin : Gm RANAP trn nh giao din SS7

bng rng v cc lp ng dng l phn iu khin kt ni bo hiu SCCP, phn

truyn bn tin MTP3-b, v lp thch ng bo hiu ATM cho cc giao din mng

SAAL-NNI.

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

Trang

Pha iukhin mngtruyn ti

Pha ngi sdng mngtruyn ti

Pha ngi sdng 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 giao

thc SS7 bng rng.

- Ngn xp giao thc pha ngi s dng : Gm mt kt ni AAL2 c dnh

trc cho tng dch v CS.

Cu trc IU PS

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

ngi s dng.

- Ngn xp giao thc pha iu khin IU PS : Cha RANAP v vt mang bo

hiu SS7. Ngoi ra cng c th nh ngha vt mang bo hiu IP ngn xp ny. Vt

mang bo hiu trn c s IP bao gm : M3UA (SS7 MTP3 User Adaption Layer),

SCTP (Simple Control Transmission Protocol), IP (Internet Protocol) v ALL5 chung

cho c hai tu chn.

- Ngn xp giao thc pha iu khin mng truyn ti IU PS : Pha iu khin

mng truyn ti khng p dng cho IU PS. Cc phn t thng tin s dng nh a

ch v nhn dng bo hiu AAL2 ging nh cc phn t thng tin c s dng trong

CS.

- Ngn xp giao thc pha ngi s dng Iu PS : Lung s liu gi c ghp

chung ln mt hay nhiu AAL5 PVC (Permanent Virtual Connection). Phn ngi s

dng GTP-U l lp ghp knh cung cp cc nhn dng cho tng lung s liu 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 giao

din ny c thit k h tr chuyn giao mm gia cc RNC, trong qu trnh

pht trin tiu chun nhiu tnh nng c b sung v n nay giao din IUr phi

m bo 4 chc nng sau :

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

Trang 42


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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 bng cho

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 tuyn

u 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 mng

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 tiu chun

thit b u cui thng tin di ng WCDMA (UTRA-FDD) m s 49-04-KTKT-TC

dnh cho cng ngh 3G.

Theo nh gi ca cc thnh vin phn bin, vic xy dng v hon thnh cng

trnh l mt vic lm cn thit, c ngha v c bit l kh thi trong giai on

hin nay, khi nhu cu pht trin ln 3G l mt xu hng tt yu Vit Nam, nht l

cc nh di ng mng GSM.

Trang 44


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Cc gii php k thut trong W-CDMA

Chng 4

CC GII PHP K THUT TRONG W-CDMA4.3 Gii thiu .

Trong chng ny chng ta s tm hiu cc k thut trong WCDMA, cc k

thut m ha, iu ch, nguyn l tri ph, cu trc phn knh v k thut truy nhp

gi 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 k

bit. Mi tin c biu din bng mt khi k thnh phn nh phn u = (u1,u2,..,un), u

c gi l vector thng tin. C tng cng 2k vector thng tin khc nhau. B m ha

s chuyn vector thng tin u thnh mt b n thnh phn v = (v 1,v2,...,vn) c gi l

t m. Nh vy ng vi 2k vector thng tin s c 2k t m khc nhau. Tp hp 2k t

m c chiu di n c gi l mt m khi (n,k). T s R = k/n c gi l t s m,

R chnh l s bit thng tin a vo b gii m trn s bit c truyn. Do n bit ra ch

ph thuc vo k bit thng tin vo, b gii m khng cn nh v c th c thc hin

bng mch logic t hp. M vng l mt tp con ca m khi tuyn tnh.

M vng l phng php m ha cho php kim tra d vng (CRC Cyclic

Redundance 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 (n-k) tng

c hm hi tip tng ng vi a thc sinh g(x).

S mch m ha vng :

Trang 45


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Nguyn l hot ng :

Bc 1 : Cng ng cho thng tin qua mch, k ch s thng tin u 0,

u1,...,un-k c dch vo mch t thit b u cui nhn trc u(x) vi x n-k.

Ngay sau khi thng tin c a vo mch th n-k ch s cn li trong thanh

ghi l nhng con s kim tra chn l.

Bc 2 : Ct t ng hi tip bng cch iu khin cho cc cng gi

h (khng cho thng tin qua).

Bc 3 : Dch cc con s kim tra chn l v a ra ng truyn. Cc

ch s kim tra ny kt hp vi k ch s thng tin to thnh vector m.

4.2.2 M xon

Trang

G1

G1

G1

G1

b1

b1

b1

b1

+

+

+

+

b0

b0

b0

b0

+

+

+

+

b2

b2

b2

b2

+

+

+

+

G2

G2

G2

G2

Gn-k-1

Gn-k-1

Gn-k-1

Gn-k-1

+

+

+

+

bn-k-1

bn-k-1

bn-k-1

bn-k-1

Thng tinxn+k.u(x)

Thng tinxn+k.u(x)

Thng tinxn+k.u(x)

Thng tinxn+k.u(x)

Cc s kimtra chn l

Cc s kimtra chn l

Cc s kimtra chn l

Cc s kimtra chn l

+

+

+

+

Mt khu ca thanh ghi dch




Cng XOR

Cng XOR

Cng XOR

Cng XORMi lin kt

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

g

g

g

gHnh 4.1. Mch m ha vng vi a thc sinhg(x) = 1 + g

1

x + g2

x2 + ...+ gn-k-1

xn-k-1 + xn-k

Cng

Cng

Cng

Cng

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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 thi gian

m cn ph thuc vo m khi bn tin trc . M xon (n,k,m) c xy dng bi

mch dy. Mch ny dng thanh ghi dch m bit lm b nh, cc u ra ca cc phn

t nh c cng vi nhau theo quy lut nht nh to nn chui m, 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 ba

khi hot ng tc bit cao vi yu cu t s li bit BER nm trong khong 10 -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 trng thi 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) cp

tn hiu s1(t) v s2(t) c s dng biu din cc gi tr nh phn. Ta c

( )[ ] ++= tfT

Ets c

b

bi .2cos.

2)( (4.1)

Trong :

Tb: rng bng thng.

Eb: Nng lng ca mt bit.

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

( ) ( ) 2,1,0,.1 == iTtit b

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

Trang 47


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Lung s tc bit Rb 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:

( )tfT

tu cb

2cos.2

)(1 = (4.2)

Ta c :

( ) ( )tutdEtS bi 1.)( = (4.3)

Khong cch gia hai tn hiu :

Trang

Hnh 4.2. S nguyn l iu ch BPSK

Lung s chai

Rb

= 1/Tb S

i(t)

bT

bE

2cos2

NRZ

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Xc sut li trong BPSK:

=

0

2

2

1

N

EerfcP be (4.4)

Vi :

Eb l nng lng ca bit .

N0 mt xc sut nhiu trng.

4.3.2 iu ch QPSK

Tn hiu iu ch QPSK c dng:

( )( )

> 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 ghi

dch :

=> 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 trong cc

thanh ghi v cc cng loi tr ng hi tip. hn ch thi gian tr, nng cao

tc ca mch to m ngu nhin ta c th s dng s mch sau :

4.4.4 Cc hm trc giao

Cc hm trc giao c s dng ci thin hiu sut s dng bng tn ca hthng DSSS. Trong h thng thng tin di ng W-CDMA mi ngi s dng mt

phn t trong cc hm trc giao. Hm Walsh v cc chui Hadamard to nn mt tp

cc hm trc giao. Trong W-CDMA cc hm Walsh c s dng theo hai cch l

m tri ph hoc cc k hiu trc giao.

Cc hm Walsh c to ra bng cc ma trn vung c bit gi c gi l cc

ma trn Hadamard. Cc ma trn ny cha mt hng ton bit 0, cc hng cn li c

Trang

Si(1) S

i(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, g

i= 1 : kha ng.

g1

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s bit 1 v s bit 0 bng nhau. Hm Walsh c cu trc cho di khi N = 2j,

trong j l mt s nguyn dng.

T hp m cc hng ca ma trn l cc hm trc giao c xc nh theo ma

trn Hadamard nh sau :

NN

NNN HH

HHHHHH ==== 2421 ,

0110

1100

1010

0000

,10

00,0

Trong NH l o c s hai ca HN.

4.5Cu trc phn knh ca WCDMA

Cng nh trong cc h thng thng tin di ng th h hai, cc knh thng tin

trong WCDMA c chia ra lm hai loi tu thuc vo quan im nhn nhn. Theo

quan im truyn dn ta s c cc knh vt l cn theo quan im thng tin ta s c

cc knh truyn ti.

Lp vt l nh hng ln n s phc tp ca thit b v mt m bo kh nng

x l bng tn c s cn thit trm gc v trm u cui. Trn quan im cc h

thng thng tin di ng th h ba l cc h thng bng rng, v vy khng th thit k

lp vt l ch cho mt dch v thoi duy nht m cn m bo tnh linh hot cho cc

dch v tng lai.

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 (DPDCH) v

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 khin

lp vt l. Thng tin ny gm : cc bit hoa tiu h tr nh gi knh cho tch sng

Trang 56


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nht qun, cc lnh iu khin cng sut (TCP : Transmit Control Power), thng tin

hi tip (FBI : Feedback Information) v mt ch th kt hp khun dng truyn ti

(TFCI).

Thng s k xc nh s bit trn khe ca DPDCH/DPCCH ng ln. Mi khung

c di 10ms c chia thnh 15 khe, mi khe di Tslot = 2560 chip ng vi 666s,

tng ng vi mt chu k iu khin cng sut. Nh vy rng khe gn bng vi

rng khe GSM (577s). Cc bit FBI c s dng khi s dng phn tp pht

vng kn ng xung. C tt c 6 cu trc khe cho DPCCH ng ln. C cc tu

chn sau : 0, 1 hay hai bit cho FBI v c hoc khng cc bit TFCI. Cc bit hoa tiu v

TPC lun lun c mt v s bit ca chng c thay i lun s dng ht khe

DPCCH.

Cu trc cc trng ca DPCCH :

Khun

dng

ti #i

Tc

bit knh

(kbit/s)

Tc

k hiu

knh

SF S

bit

/khung

S

bit

/khe

Npilot NTPC NTFCI NFBI S khe c pht

trn khung v

tuyn

0 15 15 256 150 10 6 2 2 0 15

0A 15 15 256 150 10 5 2 3 0 10 14

Trang

Hoa tiu TFCI FBI TCPN

pilotbit N

TFCIbit N

FBIbit N

TPCbit

S liu Ndata

bit

Tkhe

= 2560 chip, 10.2kbit (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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0B 15 15 256 150 10 4 2 4 0 8 91 15 15 256 150 10 8 2 0 0 8 162 15 15 256 150 10 5 2 2 1 15

2A 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 145B 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 thay

i theo khung. Thng thng i vi cc dch v s liu thay i, tc s liu ca

knh DPDCH c thng bo trn knh DPCCH. DPCCH c pht lin tc v

thng tin v tc trng c pht bng vi ch th kt hp khun dng truyn ti

(TFCI), l thng tin DPCCH v tc s liu khung DPDCH hin hnh. Nu gii

m TCFI khng ng th ton b khung s liu b mt. Tuy nhin tin cy ca

TCFI cao hn s liu nn t khi xy ra mt TCFI.

Cu trc cc trng ca DPDCH nh sau :

Khun dng

ti #i

Tc bit

knh (kbit/s)

Tc k

hiu knhSF

S bit

/khungS 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

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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 theo

phn khe vi ch th bt nhanh. C hai khung th c 15 khe truy nhp v khong cch

gia chng l l 5120 chip. Cc lp cao cung cp thng tin v khe truy nhp s dng

hin thi.

- Phn tin t ca RACH : Phn tin t ca cm truy nhp ngu nhin gm 256

ln lp mt ch k.

Trang

Knh truy nhp #0

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

#0

Khung v tuyn 10ms Khung v tuyn 10ms

5120 chip

Pht truy cp ngu nhin

Knh truy nhp #1

Knh truy nhp #7

Knh truy nhp #8

Knh truy nhp#14

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




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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 20 202 60 60 64 600 40 403 120 120 32 1200 80 80

Trng iu khin 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 Npilot NTFCI

0 15 15 256 150 10 8 2

Knh gi chung PCPCH

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

m rng ca RACH. S khc nhau c bn so vi RACH l knh ny c th dnh

trc 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 gm mt hay

nhiu tin t truy nhp (AP : Access Preamble) di 4096 chip, mt tin t pht hin

tranh chp (CDP : Collisiion Detection Preamble) di 4096 chip, mt tin t iu

khin cng sut (PCP : Power Control Preamble) di t 0 n 8 khe v mt bn tin c

di kh bin Nx10ms.

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- Phn tin t truy nhp CPCH : Phn tin t truy nhp ngu nhin CPCH tng

t nh ca RACH. S chui c s dng y c th nh hn s chui c 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 c

di 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 do

lp cao hn quy nh. Mi khung 10ms c chia ra 15 khe di 2560 chip, mi khe

gm hai phn : phn s liu mang thng tin cc lp cao v phn iu khin mang

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 knh

ring ng xung di 10ms c chia ra lm 15 khe, mi khe di 2560 chip tng

ng vi mt chu k iu khin cng sut. Cu trc khung ca knh ring ng

xung c th hin hnh sau :

Trang

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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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 mang

chui bit/k hiu c nh ngha trc.

Trang

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

S liu 1 TPC TFCI S liu 2 Hoa tiu

Ndata

bit NTPC

bit NTFCI

bit Ndata2

bit Npilot

bit

DPDCH DPCCH DPDCH DPCCH

Tslot

= 2560 chip, 10.2kbit (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 hoa tiu

chung th cp, phn bit v lnh vc s dng v cc hn ch i vi tnh nng vt l

ca chng.

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

pht qung b trn ton b .

- Knh hoa tiu chung th cp : M ngu nhin ha c th l s cp hoc th cp

v s dng m nh knh tu . Mt c th khng c hoc c nhiu knh. Chng

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.

Trang


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 v

PCH. C hai kiu knh S-CCPCH l kiu c mang TFCI v kiu khng mang TFCI.

Knh ng b (SCH)

Trang


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 chip


S liu Ndata

bit

Tslot

= 2560 chip, 20.2kbit (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 knh

con l SCH s cp v SCH th cp. Cc khung 10ms ca SCH s cp v th cp

c chia thnh 15 khe, mi khe di 2560 chip.

SCH s cp gm mt m ng b s cp PSC (Primary Synchronization) c

iu ch 256 chip, m ng b s cp nh nhau trong mi h thng. SCH th cp

gm 15 chui m c iu ch c di 256 chip. Cc m ng b th cp

(Secondary Synchrization Code) pht ng thi vi SCH s cp. Mi SSC c chn

t tp ca 16 m di 256. Chui ny SCH th cp ch th m ngu nhin ng

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 knh

dng chung ng xung. PDSCH lun c dng chung vi nhiu knh khc trn

c s ghp knh theo m.

Trang

acp

acs

1.0

acp

acs

1.1

acp

acs

1.14

SCH scp

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

acp

: M ng b s cp (Primary Synchrization Code)

acs

i,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 AI s

tng ng vi mt ch k s trn knh PRACH hoc PCPCH. AICH gm mt chui

lp ca 15 khe truy nhp lin tip (AS = Access Slot), mi khe di 40 bit. Mi khe

gm hai phn : phn ch th bt (AI) gm 32 gi tr thc a0,a1,..,a31 v mt phn khng

s dng gm 8 gi tr thc a32,a33,..a39.

Knh ch th tm gi (PICH)

Trang


S liu Ndata

bit

Tslot

= 2560 chip, 20.2kbit (k=0..6)

Hnh 4.17. Cu trc khung ca PDSCHMt khung v tuyn Tf= 10ms

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

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Knh ch th tm gi l knh vt l c tc c nh c s dng mang cc

ch th tm gi (PI). Mt khung PICH di 10ms cha 300 bit, trong 288 bit c s

dng mang thng tin, 12 bit cn li khng c nh ngha.

4.5.2 Knh truyn ti

4.5.2.1Knh truyn ti ring

Knh truyn ti ring duy nht l knh DCH c s dng mang thng tin t

cc lp trn lp vt l ring cho ngi s dng. Thng tin bao gm s liu cho dch

v hin thi v cc thng tin iu khin lp cao. Knh truyn ti ring c cc 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 hay

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 knh

truyn ti chung khng c chuyn giao mm, tuy vy mt s knh c iu khin cng

sut. So vi h thng thng tin di ng th h hai, cc knh ny c mt s im khc

nh truyn dn gi cc knh chung, dng chung mt knh ng xung pht s

liu gi

Trang

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 dng

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 knh

truyn ti ng xung mang thng tin iu khin n cc UE nm trong mt cho

trc. Knh FACH cng c th truyn cc gi s liu. Khi c nhiu knh FACH, cc

knh b sung c th c tc bit cao hn. FACH khng s dng iu khin cng

sut nhanh v cc thng tin c pht phi cha thng tin nhn dng trong bng.

Knh tm gi (PCH)

Knh tm gi PCH (Paging Channel) l mt knh truyn ti ng xung mang

s 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 ting ln c s dng mang thng tin iu khin t UE. Knh ny cng c th

s dng pht i cc cm nh s liu gi t UE. hot ng ng, h thng 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 ca knh

RACH mang s liu ca ngi s dng c pht theo gi trn ng ln. KnhCPCH cng vi knh FACH ng xung to nn cp knh truyn s liu.

Knh ng xung dng chung (DSCH)

Knh ng xung dng chung DSCH (Dedicated Shared Channel) l knh

truyn ti mang thng tin ca ngi s dng, ngoi ra DSCh cng c th mang

thng tin iu khin. DSCH h tr iu khin cng sut nhanh v c th c dng

chung cho nhiu ngi s dng.

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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 knh

vt l th hin s sau :

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

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

vt l cn thit.

4.6 Truy nhp gi trong W-CDMA

4.6.1 Tng quan v truy nhp gi trong W-CDMA

Truy nhp gi trong W-CDMA cho php cc vt mang khng phi thi gian

thc s dng ng cc knh chung, ring v dng chung. Vic s dng cc knh

Trang

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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khc nhau c iu khin bi b lp biu gi PS (Packet Scheduler). B lp biu

gi thng c t RNC v ti y vic lp biu gi c th thc hin hiu qu cho

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 tng ngi

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 quan

im 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 gi

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

- Cc gi c th c pht li bi lp iu khin kt ni v tuyn (RLC). iu

ny cho php s dng cht lng ng truyn v tuyn km hn v t s li khung

cao 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 dng

gia cc ngi s dng. B lp biu gi c th quyt nh tc bit phn b v thi

gian phn b. Thut ton lp biu gi trong W-CDMA c thc hin theo hai

phng php : phn chia theo m v phn chia theo tn s. Trong phng php phnchia theo m, khi c nhu cu tng dung lng th tc bit phn b cho ngi s

dng s gim i. Trong phng php phn chia theo thi gian biu dung lng c

dnh cho mt s t ngi theo tng thi im, nh vy ngi s dng c th c tc

bit cao nhng ch c th s dng trong thi gian ngn. Trong trng hp s ngi

s dng tng th phi i truyn dn lu hn. Thc t qu trnh lp biu 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 hiu

nng v tuyn. Thng thng cc dch v tc bit cao i hi t nng lng bit hn,

v th phn chia theo thi gian c u im l Eb/No thp hn. Ngoi ra thi gian tr

trung bnh trong phng php ny l ngn hn so vi phng php phn chia theo

m.

Trang

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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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 ni i hi

thi gian di thm ch n vi khung.

- Vic s dng phn b theo thi gian b hn ch bi di tc cao do hn ch

cng sut ca MS ng ln.

- Phng php ny s dng cc tc bit cao v to ra lu lng dng cm,

iu ny dn n s thay i cao cc mc nhiu so vi lp biu phn chia theo 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 knh

khi h cn chng. Nu nhiu ngi s dng gi yu cu lu lng th tc bit 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 tn

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 thi gian

hn lp biu gi phn chia theo thi gian. iu ny cho php d bo c mc

nhiu.

- Lp biu phn chia theo m c th l tnh hoc ng. Trong lp biu tnh, tc

bit c phn b duy tr c nh trong sut thi gian kt ni. Trong lp biu ng,

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 trong

WCDMA . Trn c s ngi ta tin hnh qui hoch mng WCDMA.

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Quy hoch mng W-CDMA

Chng 5

QUY HOCH MNG W-CDMA5.1 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,Qu trnh

quy hoch mng v tuyn cho h thng thng tin di ng th h ba bao gm cc bc

sau : nh kch c, quy hoch lu lng v vng ph sng, ti u ha mng.

Giai on nh kch c s a ra d tnh s i trm, s trm gc, cu hnh cc phn

t gc v cc phn t mng khc trn c s cc yu cu ca nh khai thc trong vng.

nh c phi thc hin c cc yu cu ca nh khai thc v vng ph, dung lng

v cht lng phc v. Vic quy hoch dung lng v vng ph phi c xem xt

Trang

Cc yu cu vngph Yu cu dung

lng Kiu vng, mhnh truyn sngv tuyn

u vo

Suy 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 s

RRM

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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Quy hoch mng W-CDMA

ng thi do dung lng v vng ph c quan h cht ch vi nhau trong mng di

ng. Khi mng i vo hot ng, c th tnh ton hiu nng mng bng cc php o

v cc kt qu o c s dng hin th v ti u ho hiu 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 ng

truyn cc i cho php m bo cng tn hiu ph hp bin gii cho cht

lng ting chp thun trn 90% vng ph. Tn hao ng truyn cho php l hiu

s gia cng sut pht x hiu dng ca my pht v cng tn hiu ti thiu cn

thit my thu cho cht lng ting chp thun. Cc thnh phn xc nh tn haong 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 + Gb Lc Lb Lh (5.1)

Vi :

Pmin = N0 + Fb + (Eb/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.

Gb : H s khuch i ca Anten pht BS.

Lc : Tn hao cp Anten thu BS.

Lb : Tn hao c th.

Lh : Tn hao truy nhp ta nh.

B : Tc bit (Bps)

N0 : Tp m nn ca BS.

Fb : H s tp m my thu.

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Quy hoch mng W-CDMA

Eb/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 (R) cc

i tho mn yu cu truyn nhn thng tin da vo cc m hnh truyn sng. Do c

im truyn sng khng n nh, nn cc m hnh truyn sng u mang tnh thc

nghim. Di y ta xt hai m hnh truyn sng c s dng rng ri l m 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 Hata.

M hnh Hata l quan h thc nghim c rt ra t bo co k thut ca Okumura

cho php s dng cc kt qu vo cc cng c tnh ton. Cc biu thc c s dng

trong m hnh Hata xc nh tn hao trung bnh :

Vng thnh ph

Lp= 69,55+26,16.lgfc 13,28.lghb a(hm) + (44,9-6,55.lghb).lgR (dB) [6] (5.3)

Trong :

fc : Tn s hot ng (MHz).

Lp : Tn hao cho php.

hb : 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 :

MHzfc 1500150

30 hb 200m

1 hm 10m

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Documents

Thuyet Minh Do an Tot Nghiep-2007