Download - Thuyet Minh Do an Tot Nghiep-2009
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
1/92
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
Trang 1
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
2/92
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
Trang 2
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
3/92
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
Trang 3
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
4/92
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
Trang 4
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
5/92
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.
Trang 5
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
6/92
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
Trang 6
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
7/92
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
Trang 7
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
8/92
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.
Trang 8
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
9/92
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.
Trang 9
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
10/92
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
Trang 10
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
11/92
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.
Trang 11
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
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).
Trang 12
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
13/92
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 Trng Hong Hoa Thm v cc thy c
gio gip em hon thnh n ny !.
Tp hcm, ngy 11 thng 7 nm 2009.
Ngi thc hin
Trang 13
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
14/92
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).
Trang 14
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
15/92
Tng quan v thng tin di ng s
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
Trang 15
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
16/92
Tng quan v thng tin di ng s
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
Trang 16
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
17/92
Tng quan v thng tin di ng s
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.
Trang 17
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
18/92
Tng quan v thng tin di ng s
-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 :
Trang 18
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
19/92
Tng quan v thng tin di ng s
- 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,
Trang 19
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
20/92
Tng quan v thng tin di ng s
Trang 20
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
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.
Trang 21
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
22/92
Gii thiu h thng thng tin di ng GSM
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
Trang 22
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
23/92
Gii thiu h thng thng tin di ng GSM
(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
Trang 23
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
24/92
Gii thiu h thng thng tin di ng GSM
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
Trang 24
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
25/92
Gii thiu h thng thng tin di ng GSM
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
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 chung 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 tr trong ccthanh 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:
Trang 25
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
26/92
Gii thiu h thng thng tin di ng GSM
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
Trang 26
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
27/92
Gii thiu h thng thng tin di ng GSM
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
27
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
28/92
Gii thiu h thng thng tin di ng GSM
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.
Trang 28
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
29/92
Gii thiu h thng thng tin di ng GSM
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
29
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
30/92
Gii thiu h thng thng tin di ng GSM
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
Trang 30
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
31/92
Gii thiu h thng thng tin di ng GSM
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
31
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
32/92
Gii thiu h thng thng tin di ng GSM
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
32
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
33/92
Gii thiu h thng thng tin di ng GSM
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 .
Trang 33
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
34/92
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
Trang 34
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
35/92
Cng ngh di ng th h ba W-CDMA
: 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
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
36/92
Cng ngh di ng th h ba W-CDMA
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
36
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
37/92
Cng ngh di ng th h ba W-CDMA
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.
Trang 37
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
38/92
Cng ngh di ng th h ba W-CDMA
- 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.
Trang 38
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
39/92
Cng ngh di ng th h ba W-CDMA
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
39
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
40/92
Cng ngh di ng th h ba W-CDMA
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.
Trang 40
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
41/92
Cng ngh di ng th h ba W-CDMA
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
41
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
42/92
Cng ngh di ng th h ba W-CDMA
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
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
43/92
Cng ngh di ng th h ba W-CDMA
- 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.
Trang 43
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
44/92
Cng ngh di ng th h ba W-CDMA
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
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
45/92
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
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
46/92
Cc gii php k thut trong W-CDMA
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
Mt khu ca thanh ghi dch
Mt khu ca thanh ghi dch
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
46
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
47/92
Cc gii php k thut trong W-CDMA
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
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
48/92
Cc gii php k thut trong W-CDMA
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
48
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
49/92
Cc gii php k thut trong W-CDMA
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:
( )( )
> 0) :
( ) 011
1 ... gxgxgxgxgm
mm
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)}
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)
Trang
ci
Si(1) S
i(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.
54
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
55/92
Cc gii php k thut trong W-CDMA
=> 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
55
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
56/92
Cc gii php k thut trong W-CDMA
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
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
57/92
Cc gii php k thut trong W-CDMA
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
57
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
58/92
Cc gii php k thut trong W-CDMA
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
Trang 58
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
59/92
Cc gii php k thut trong W-CDMA
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
Pht truy cp ngu nhin
Pht truy cp ngu nhin
Pht truy cp ngu nhin
59
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
60/92
Cc gii php k thut trong W-CDMA
- Phn bn tin ca RACH : Khung v tuyn phn bn tin 10ms c chia thnh
15 khe, mi khe di Tslot = 2560 chip. Mi khe gm hai phn : phn s liu mang
thng tin lp 2 v phn iu khin mang thng tin lp 1. C hai phn c pht ng
thi. Phn s liu gm 10.2k bit vi k = 0, 1, 2, 3. Phn iu khin gm 8 bit hoa tiu
h tr s nh gi cho tch sng nht qun v hai bit TFCI . Tng s bit TFCI
trong bn tin truy nhp ngu nhin l 30. Gi tr ca TFCI tng ng vi mt khun
dng truyn ti nht nh ca bn tin truy nhp hin thi.
Cc trng s liu ca phn bn tin RACH :
Trang
Tin t Tin t Tin t
Tin t Tin t
Phn bn tin
Phn bn tin
4096 chip
4096 chip
10ms (Mt khung v tuyn)
20ms (Hai khung v tuyn)
Hnh 4.9. Cu trc pht truy nhp ngu nhin
Tin t
S liu Ndata bit
Khe #0 Khe #1 Khe #14Khe #i
Khung v tuyn phn bn tin TRACH
= 10
Hoa tiu Npilot
bit
Tslot
= 2560 chip, 10.2kbit (k=0..3)
S liu
iu khin
Hnh 4.10. Cu trc khung v tuyn phn bn tin RACH
60
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
61/92
Cc gii php k thut trong W-CDMA
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.
Trang 61
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
62/92
Cc gii php k thut trong W-CDMA
- 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
62
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
63/92
Cc gii php k thut trong W-CDMA
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
63
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
64/92
Cc gii php k thut trong W-CDMA
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
Khe #0 Khe #1 Khe #i 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
Mt khung v tuyn Tf= 10ms
64
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
65/92
Cc gii php k thut trong W-CDMA
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
Khe #0 Khe #1 Khe #i Khe #14
S liu 18 bit
Tslot
= 2560 chip, 20 bit
Hnh 4.14. Cu trc khung ca knh vt l iu khin chung s cp
Mt khung v tuyn Tf= 10ms
Tx tt
256 chip
Khe #0 Khe #1 Khe #i Khe #14
S liu Ndata
bit
Tslot
= 2560 chip, 20.2kbit (k = 0..6)
Hnh 4.15. Cu trc khung ca S-CCPCH
Mt khung v tuyn Tf= 10ms
TFCI NTFCI
bit Hoa tiu Npilot
bit
65
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
66/92
Cc gii php k thut trong W-CDMA
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)
66
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
67/92
Cc gii php k thut trong W-CDMA
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
Khe #0 Khe #1 Khe #i Khe #14
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
67
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
68/92
Cc gii php k thut trong W-CDMA
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
68
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
69/92
Cc gii php k thut trong W-CDMA
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.
Trang 69
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
70/92
Cc gii php k thut trong W-CDMA
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
70
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
71/92
Cc gii php k thut trong W-CDMA
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.
Trang 71
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
72/92
Cc gii php k thut trong W-CDMA
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
72
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
73/92
Cc gii php k thut trong W-CDMA
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.
Trang 73
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
74/92
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.
-
74
-
7/31/2019 Thuyet Minh Do an Tot Nghiep-2009
75/92
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 p