Nguyen Thai Binh

B GIO DC V O TO TP ON BU CHNH VIN THNG VIT NAM

HC VIN CNG NGH BU CHNH VIN THNG VIT NAM

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

NGUYN THI BNH

NGHIN CU CC VN THIT K V TRIN KHAI TRM GC BTS CHO 3G WCDMA UMTS

CHUYN NGNH: K THUT IN T

M S: 60.52.70

TM TT LUN VN THC S K THUT

H NI NM 2011

Lun vn c hon thnh ti: Hc vin Cng ngh Bu chnh Vin thng Tp on Bu chnh Vin thng Vit Nam

Ngi hng dn khoa hc: TS NGUYN PHM ANH DNG

Phn bin 1: ....................................................................................................... ............................................................................................................................ Phn bin 2: ...................................................................................................... .......................................................................................................................... Lun vn s c bo v trc hi ng chm lun vn ti Hc vin Cng ngh Bu chnh Vin thng Vo lc: ........gi.......ngy........thng........nm.......... C th tm hiu lun vn ti: - Th vin Hc vin Cng ngh Bu chnh Vin thng

M U

WCDMA l mt cng ngh s dng giao din v tuyn theo tiu chun 3GPP

trong cc h thng thng tin di ng th h 3. Giao din ny h tr tc s liu ln

n 2Mbps trn sng mang c bng tn 5MHz. Hin nay HSPA c a ra vi

tc s liu nh 14,4Mbps cho R5 HSDPA v 5,7Mbps cho R6 HSUPA. BTS l

phn t quan trng nht ca mng truy nhp v tuyn trong h thng thng tin di

ng. Mi BTS bao gm phn x l tn hiu v tuyn v phn x l tn hiu bng

gc. pht trin mt mng v tuyn vi vng ph v hiu nng tt, cn trin khai

hng nghn BTS. V th gi thnh cc BTS chim t l ln nht trong tng gi thnh

xy dng mng. Do vic nghin cu kin trc trm gc 3G WCDMA UMTS ht

sc quan trng c bit l phn x l tn hiu bng gc.

Mc ch ca ti th hin r qua tn ca ti: Nghin cu cc vn

thit k v trin khai trm gc BTS cho 3G WCDMA UMTS.

Cu trc lun vn gm cc phn: Phn m u; Chng 1, 2 v 3; Phn kt

lun v cc hng nghin cu tip theo; Ti liu tham kho v Ph lc. c trnh

by trong 3 chng nh sau:

Chng 1: Tng quan h thng WCDMA.

Chng 2: Cc vn thit k trm gc BTS cho 3G WCDMA UMTS.

Chng 3: Trin khai trm gc BTS cho 3G WCDMA UMTS.

Chng 1

TNG QUAN H THNG WCDMA

1.1. Qu trnh pht trin thng tin di ng

Cc cng ngh TTD c chia thnh ba th h: th nht, th hai, th ba v

th t c vit tt l 1G, 2G, 3G v 4G. Cc h thng 1G m bo truyn dn

tng t da trn FDM vi kt ni mng li da trn TDM. Khc vi 1G, cc cng

ngh 2G c thit k trin khai quc t. Thit k 2G nhn mnh hn ln tnh

tng thch, kh nng chuyn mng phc tp v s dng truyn dn ting s ha

trn v tuyn.

C th coi mt h thng TTD l 3G nu n p ng mt s cc yu cu c

ITU ra:

Hot ng trong mt trong s cc tn s c n nh cho cc dch v 3G

Phi cung cp dy cc dch v s liu mi cho ngi s dng bao gm c a

phng tin, c lp vi cng ngh giao din v tuyn

Phi h tr truyn dn s liu di ng ti 144 kbps cho cc ngi s dng di

ng tc cao v truyn dn s liu ln n 2Mbps cho cc ngi s dng c nh

hoc di ng tc thp

Phi cung cp cc dch v s liu gi

Phi m bo tnh c lp ca mng li vi giao din v tuyn

Qu trnh nghin cu pht trin UMTS ln 3G pht trin v tin dn n 4G l

vic a ra cng ngh HSPA v LTE.

hnh 1.1: L trnh pht trin ln th h 4

1.2. Kin trc chung ca mt h thng thng tin di ng 3G.

Kin trc tng qut ca h thng 3G WCDMA UMTS c cho trn hnh 1.2

bao gm : thit b ngi s dng UE, mng truy nhp UTRAN, mng li CN.

Hnh 1.3: H thng 3G

UMTS kt hp PS v CS

3G c th s dng hai kiu RAN. Kiu th nht s dng cng ngh a truy

nhp WCDMA c gi l UTRAN. Kiu th hai s dng cng ngh a truy nhp

TDMA c gi l GERAN.

1.3. Chuyn mch knh (CS), chuyn mch gi (PS), dch v chuyn mch

knh v dch v chuyn mch gi.

Chuyn mch knh (CS: Circuit Switch) thit b chuyn mch thc hin cc

cuc truyn tin bng cch thit lp kt ni chim mt ti nguyn mng nht nh

trong ton b cuc truyn tin. Kt ni ny l tm thi, lin tc v dnh ring.

Chuyn mch gi (PS: Packet Switch) thc hin phn chia s liu ca mt

kt ni thnh cc gi c di nht nh v chuyn mch cc gi ny theo thng tin

v ni nhn c gn vi tng gi v PS ti nguyn mng ch b chim dng khi

c gi cn truyn.

Dch v chuyn mch knh (CS Service) mi u cui c cp pht mt

knh ring v n ton quyn s dng ti nguyn ca knh ny trong thi gian cuc

gi

Dch v chuyn mch gi (PS Service) nhiu u cui cng chia s mt knh

v mi u cui ch chim dng ti nguyn ca knh ny khi c thng tin cn truyn

v n ch phi tr tin theo lng tin c truyn trn knh.

1.4. Cc loi lu lng 3G WCDMA UMTS h tr

Loi hi thoi (Conversational, rt)

Loi lung (Streaming, rt)

Loi tng tc (Interactive, nrt)

Loi nn (Background, nrt)

1.5. Cc giao thc trn giao din v tuyn.

Ging nh GSM, ngn xp giao thc giao din v tuyn ca UMTS cng

gm ba lp, tuy nhin trong UMTS c hai loi ngn xp giao thc: mt ngn xp

cho mt phng iu khin v mt ngn xp giao thc cho mt phng ngi s dng.

Hnh1.4.Ngn xp giao thc giao din v tuyn ca 3GWCDMA UMTS: a)mt

phng ngi s dng , b) mt phng iu khin .

Ngn xp giao thc 3G HSPA UMTS trong mt phng ngi s dng (UP).

MAC-hs v MAC-e c b sung cho HSDPA v HSUPA iu khin lp biu

nhanh v HARQ. Ngoi ra lp con MAC-es c b sung cho HSUPA sp xp

li cc gi sau qu trnh HARQ.

1.6. Cc knh trn giao din v tuyn ca 3G UMTS.

1.6.1 Cc knh trn giao din v tuyn ca 3G WCDMA UMTS.

Cc knh ca WCDMA c chia thnh cc loi knh sau:

- Knh Logic (LoCH)

- Knh truyn ti (TrCH)

- Knh vt l (PhCH). Knh mang cc knh truyn ti.

1.6.2 Cc knh trn giao din v tuyn ca 3G HSPA UMTS

Tng t nh 3G WCDMA UMTS, 3G HSPA UMTS cng c cc knh LoCH,

TrCH v PhCH. Ngoi cc knh c ca WCDMA, HSPA cn c th mt s knh

mi: HS-DPCCH, HS-DSCH, HS-PDSCH, HS-SCCH

1.7. Lp vt l

1.7.1 Cc thng s lp vt l.

Cc thng s lp vt l ca WCDMA UMTS c cho trong bng 1.1.

W-CDMA S a truy nhp DS-CDMA bng rng rng bng tn (MHz) 5/10/15/20 Mnh ph 200 kHz Tc chip (Mcps) (1,28)/3,84/7,68/11,52/15,3 di khung 10 ms ng b gia cc nt B D b/ng b M ha sa li M turbo, m xon iu ch DL/UL QPSK/BPSK Tri ph DL/UL QPSK/OCQPSK (HPSK) B m ha thoi CS-ACELP/(AMR) T chc tiu chun 3GPP/ETSI/ARIB

Bng 1.1 : Lp vt l ca 3G WCDMA UMTS

1.7.2 Quy hoch tn s.

Hnh 1.11. Phn b tn s cho 3G UMTS. a) Cc bng c th dng cho 3G UMTS

FDD ton cu; b) Bng tn IMT-2000

Ti Vit Nam bng tn 3G UMTS FDD c cp pht tn s theo tm khe tn

s nh cho trong bng 1.1, trong hai hoc nhiu nh khai thc c th cng tham

gia xin cp pht chung mt khe.

Bng 1.2. Cp pht tn s 3G UMTS ti Vit Nam

Khe

tn s

FDD TDD

BSTx BSRx BSTx/BSRx

A 2110-2125

MHz

1920-1935

MHz

1915-1920

MHz

B 2125-2140

MHz

1935-1950

MHz

1910-1915

MHz

C 2140-2155

MHz

1950-1965

MHz

1905-1910

MHz

D 2155-2170

MHz

1965-1980

MHz

1900-1905

MHz

Chng 2

NGHIN CU CC VN THIT K TRM GC BTS CHO 3G

WCDMA UMTS

2.1. Kin trc c s ca 3G WCDMA UMTS BTS

Kin trc in hnh ca mt trm thu pht gc 3G WCDMA UMTS (hnh 2.1)

bao gm bn phn chnh: phn v tuyn (RF: Radio Frequency), phn bng gc

(BB: Baseband), phn iu khin v truyn dn. Module RF pht/thu cc tn hiu v

bin i tn hiu s vo sng v tuyn v ngc li. Module bng gc (BB: Base

Band)) x l tn hiu c m ha trc khi pht/thu n n t mng li thng qua

module truyn dn. Khi iu khin ng vai tr iu phi ba module ni trn.

Chc nng ca trm gc c chia thnh hai phn chnh:

- Cc chc nng mt phng iu khin lin quan n truyn dn s liu iu

khin, s liu khai thc v bo dng (O&M: Operation and Maintenance).

- Cc chc nng mt phng ngi s dng lin quan n truyn ti, bng gc

v anten.

Hnh 2.1. Kin trc chung ca mt BTS

2.2. Cc chc nng bng gc v cc vn thit k bng gc

2.2.1. Chc nng bng gc

Cc phin bng gc c th thc hin cc chc nng lp vt l sau:

Sp xp v gii sp xp cc knh vt l v cc knh truyn ti

Ghp v phn knh

M ha v gii m

Tri ph v gii tri ph

iu ch v gii iu ch

Cc th tc lp vt l v

Cc o c lp vt l

Lp cu hnh trm gc v tuyn

iu khin

Phn phi thng tin h thng

Lp cu hnh lin kt v tuyn cho cc knh ring v chung

X l lung s liu Iub v

ng b v phn phi nt

Cc chc nng bng gc trong BTS cung cp nn tng cho cc chc nng mng

v tuyn, cc chc nng lp cu hnh v cc chc nng O&M. Do , bng gc to

nn nn tng x l cc knh chung v cc knh ring cho cc lp cao hn.

Hnh 2.3. M hnh

chuyn i knh (sp xp knh)

2.2.2. Cc vn thit k bng gc.

Bng gc c thit k ph hp vi tiu chun 3GPP cho WCDMA. Ngoi ra

kin trc bng gc c thit k p ng vi cc yu cu m bo hot ng cc

trm gc. Cc yu cu ny gm: tnh linh hot cu hnh, s dng hiu qu cc ti

nguyn, d trin khai, tng thch v phn cng sn sng cho tng lai.

2.2.3. Thit k phin x l bng gc pht (TXBBB).

2.2.3.1. Cc chc nng x l ng xung.

Hnh 2.4 cho thy cc khi chc nng chnh x l ng xung. X l u

tin l x l giao thc khung (FP). Sau khi bit khi no th cc khung s liu trn

cc knh chung ( PCH v FACH) v cc knh ring (DCH) s n t giao din Iub,

b x l giao thc khung ng b cc khung v ly ra phn ti tin ca khung s

liu. Phn ti tin cha cc knh truyn ti khng c m ha.

Hnh 2.4. Cc khi chc nng x l ng xung

2.2.3.2. Thc hin phin TX bng gc (TXBBB)

Thc hin TXBBB c chia thnh 2 phn: b x l phin v phn cng c th

phin. B x l phin iu khin phin v cc phn lu lng. Phn cng c th

phin x l s liu ca ngi s dng gi n giao din v tuyn. Phn cng ny

M ha BCH

M ha PCH

M ha FACH

M haDCH

PCH FP

FACH FP

DCH FP Chia MUX

Tri ph v iu ch

G/D Iub

GD DL/UL

G/D n TRX

G/D: giao din

cha b s l giao din mt phng ngi x dng Iub, b x l tc k hiu, b

x l tc chip v b iu khin x l lp vt l.

Hnh 2.5 Thc hin phin TXBBB cho mt phng ngi s dng

2.2.4. Thit k phin x l bng gc thu (RAXBBB)

Trn ng ln, tn hiu nhn c t giao din v tuyn c a vo bng gc

di dng tn hiu s t phn v tuyn TXB. i vi knh vt l ring (DPCH), tn

hiu n t TRX c x l trong khi chc nng ca b gii iu ch. Khi ny

cng cha b tm ng v my thu RAKE.

Hnh 2.6. Cc khi chc nng x l ng ln ca TXB

2.2.5 Thc hin RAXB bng gc (RAXBBB)

Phin x l ng ln bng gc (RAXBBB) c chia thnh hai phn chnh: B

x l phin (BP: Board Processor) v phn cng x l s liu c th phin (DP:

Data processing). B x l phin iu khin phin v cc phn lu lng. Phn

cng DP x l s liu ca ngi s dng nhn c t giao din v tuyn n giao

din Iub.

Hnh 2.7.Cc khi trn phin RAXBBB

2.3. Kin trc u pht v tuyn a bng (MBFE

Hin nay cc u thu pht v tuyn ca 3G WCDMA BTS u c thit k

c th phc v 4 sng mang trn cng 1 bng tn WCDMA, ngoi ra cc nh sn

xut cng ang hng ti thit k cc BTS lm vic trong nhiu bng tn WCDMA

v c cc bng tn ca cng ngh truy nhp v tuyn khc. Cc u thu pht v

tuyn a bng p ng c yu cu ny.

Hnh 2.8. Kin trc tng qut ca MBFE

2.4. B khuch i cng sut a sng mang (MCPA)

MCPA cho cc h thng WCDMA phi tha mn cc yu cu :

- Tuyn tnh cao: tha mn cc yu cu ca 3GPP.

- Hiu sut ti u: gim tiu th cng sut trm gc.

- C th sn xut t ng vi s lng ln.

2.4.1. MCPA sa mo thun.

Hnh 2.9 S khi ca MCPA sa mo thun cho WCDMA

Tn hiu u vo MCPA sa mo thun c chia thnh 2 ng. Tn hiu trong

ng trn c khuch i bi b khuch i chnh MPA, b khuch i ny lm

vic trong ch AB. Cc mo phi tuyn trong MPA dn n mo iu ch giao

thoa v mo ny cng vo tn hiu. Mu tn hiu u ra mPA c a vo b tr (

b ghp nh hng), ti y tn hiu b tr bi mt phn tn hiu gc c lm tr (

l tng ton b tn hiu gc b loi b). Tn hiu li c khuch i tuyn tnh

trong b khuch i li EPA n mc cn thit loi b mo trong ng chnh,

sau c a ln b ghp ti u ra. Tn hiu u ra MPA c tr ph hp

vi ng khuch i li. Mo ca hai ng c cng ngc pha nhau v l

tng s ch cn li tn hiu gc ti u ra ca b khuch i cng sut a sng

mang MCPA.

2.4.2. MCPA vi lm mo ngc trong min s

Cng ngh bn dn hin i cung cp cc k thut DSP, ADC v DAC ci tin

cho php thit k MCPA hon ton da trn lm mo trc trong min s DPD.

Nh vy lm gim gi thnh v t hiu sut cao hn. Mu tn hiu v tuyn ti u

ra b bin i h tn RF c so snh vi tn hiu u vo s. S khc bit c

gim thiu bng cch lm mo trc tn hiu u vo trong vi mch ASIC s c

iu khin bi DSP c nhim v cp nht thch ng.

2.5. Trm gc phn b

Trong kin trc trm gc phn b DBS, cc n v v tuyn t xa RRU c coi

l cc phn t pht v thu cc tn hiu v tuyn, cc n v bng gc BBU c coi

l cc phn t x l v pht cc tn hiu bng gc t/n RNC. Thit k phn b

DBS cho php cc nh khai thc di ng trin khai cc RRU v h thng ngun tch

ring so vi BBU. Cc RRU v BBU c th c kt ni vi nhau bng cp quang

n mode.

Hnh 2.14. (a) BTS thng thng (b) BTS phn b

2.6. Trm gc a chun a bng v cng ngh v tuyn c nh ngha bng

phn mm.

Cng ngh SDR cung cp gii php hiu qu, t tn km xy dng cc trm

gc v tuyn a mode, a bng, a chc nng. Khng tn ti mt nh ngha duy

nht cho SDR. C th coi cng ngh SDR l kt hp ca cc cng ngh phn mm

v phn cng m c th lp li cu hnh ca cc b phn hot ng quan trng bng

cch nng cp phn mm. SDR cho cc gii php a chun, a bng theo cc tiu

ch sau:

1. a bng, n chun:

- 1,8/2,1/2,6 GHz: WCDMA UMTS

- 2,5/3,5 GHz: WIMAX/IEEE 802.16e

2. a chun trong mt tn s

- 2,1 GHz: WCDMA UMTS, HSPA, LTE

3. a chun, a bng

- 1,8/2,1/2,6 GHz: WCDMA UMTS, HSPA, LTE

- 1,8/2,1/2,6/3,6GHz:WCDMA UMTS, HSPA, LTE, WIMAX

Chng 3

TRIN KHAI TRM GC BTS CHO 3G WCDMA UMTS

3.1 Trin khai BTS 3G hin nay

Mc tiu ca lp k hoch mng v tuyn l thit k h thng mng cho php s

dng hiu qu thit b v ph tn hin c vi chi ph hp l. i vi a phn cc

trng hp mng hin nay, vic thit k vi cc rng buc l c trng. Cc rng

buc theo t hin trng thc t l cc mng UMTS phi ph kn mng hin c.

Mng ph kn s dng cng ngh khc nhau cng vi cc tn s tng t hoc khc

nhau. Kch bn ny thng mang n nhiu thch thc trong vic thit k, c bit

l:

- Cc thch thc v hiu nng ph sng;

- Cc gii php v site v co-siting;

- Quy hoch v phng php truyn dn;

- So snh cng ngh v nhn thc ca ngi dng cui cng;

3.1.1. Quy trnh lp k hoch ng thi.

Trng hp in hnh s l mt nh mng m c sn mt mng li GSM

v nhn c giy php cho mng WCDMA. Vic s dng cc trm GSM hin

c v cc trm WCDMA cng v tr vi cc trm GSM l gii php u tin t quan

im nh mng.

+ Ti s dng cc trm

+ Cc gii php v trm: Co-located Sites; Co-siting

+ Cu hnh anten

+ Phn phi dch v v lu lng gia cc h thng

+ Dung lng v vng ph

3.1.2. K hoch truyn dn

+ Cu trc truyn dn

+ Cc phng php truyn dn

+ Chia s truyn dn gia cc h thng

3.2. Gii php trin khai BTS 3G

3.2.1. Cu hnh mng DBS

3.2.1.1. Cc gii php truyn dn cho mng truy nhp v tuyn di ng

- Mng quang ring im n im thu thp s liu di ng.

- Gii php s dng mng quan th ng gi

3.2.1.2. Cu hnh mng DBS chia s chung cc khung modem hay khi nim

khch sn nt B

Mng truyn dn c xy dng trn cc ng quang ring im n n im,

c th s dng mt hoc hai si quang cho mt RRU, trong mt s cu hnh mt

RRU c th h tr ba on .

- Cu hnh khch sn nt B vi BBU phn tn.

- Cu hnh khch sn nt B vi BBU t tp trung.

3.2.1.3. S dng hai si quang trn mng PON gi

Nu lc u cc RRU c kt ni qua mng ring th bc tip theo c th tin

ti s dng hai si quang trn mng mng PON gi nh hnh 3.8.

Hnh 3.8. Tin ti s dng h tng PON gi

3.2.1.4. PON gi hon ton

Mng truyn dn s liu di ng c th tin ti xy dng trn c s hon tan

PON gi nh hnh 3.9.

Hnh 3.9: Gii php PON gi hon ton

3.2.2. Gii php mm do nng cp trm gc BTS SDR

Vi k thut SDR, cc nh khai thc di ng c th nng cp h thng mng n

phin bn mi nht m khng phi thay i phn cng, do lm gim tng chi ph

TCO. Thm na, thit b SDR gip ci thin thi gian a sn phm ra thng mi,

lm gim ng k ri ro u t ca nh khai thc.

Gii php h thng SDR ca ZTE

Cc sn phm SDR ca ZTE da trn nn tng vi TCA tin tin vi thit k theo

module kin trc phn tn v tnh tch hp cao. Khi bng tn gc BB h tr cc

tiu chun GSM/WCDMA/CDMA v khi v tuyn RU h tr cc gii php a

C v

trung tm

Gi phi si quang

Lu lng ng ln (cm) 1,31 m Lu lng ng xung (lin tc) 1,49 m

u cui ng quang (OLT: Optical Line

Terminal)

Modem: u cui mng quang (ONT:

Optical Network Terminal)

RNC

Chuyn mch

ATM/IPRRU

RRU kt hp phn v tuyn v ONT

bng tn. S kt hp gia cc BB v RRU khc nhau to ra cc Node B SDR khc

nhau. Cc sn phm ca ZTE c cc tnh nng sau:

- Dung lng ln v kh nng a bng tn.

- Khuch i cng sut hiu qu cao.

- Nn tng vi TCA thng nht.

- Nng cp mm do.

- HSPA hiu sut cao.

KT LUN V HNG NGHIN CU TIP THEO

Lun vn t c mc ch nghin cu ban u l nghin cu cc vn

thit k trm gc BTS cho 3G WCDMA UMTS, cc cu trc c bn ca mt nt B

v phn tch thng k mng WCDMA & GSM hin ti xut phng n xy dng

mng t hiu qu cao cng nh m bo cht lng. C th:

- Tm tt qu trnh pht trin ca h thng thng tin di ng th h 3. Trnh

by cc khi nim, cu trc v chc nng ca cc phn t trong h thng 3G.

- Trnh by kin trc c s ca 3G WCDMA UMTS.

- Cc chc nng bng gc v cc vn thit k bng gc, kin trc u pht

v tuyn a bng, b khuch i cng sut a sng mang.

- Trm gc phn b, trm gc a chun a bng v cng ngh v tuyn c

nh ngha bng phn mm.

- Cc ch tiu k thut i vi 3G WCDMA UMTS.

- Qui trnh trin khai 3G hin nay v gii php

Kin ngh cc hng nghin cu tip theo:

Cng ngh SDR ha hn s mang li mt tim nng to ln cch mng ha cc

thit b v tuyn c thit k, sn xut, pht trin v s dng theo cch thng thng.

V thit b v tuyn SDR l dng mi ca kin trc thit b v tuyn nn chng bao gm

rt nhiu cc k thut thit k to ra mt thit b thu pht vi tnh nng mm do ch

thc. Lnh vc ny rt rng bao gm: thit k cc h thng RF, IF v thit k phn cng

bng gc analog, thit k phn cng s v k thut phn mm. thc hin c nhim

v ny cn phi tip tc nghin cu rt nhiu vn nh:

- Thc hin la chn kin trc my thu mm do c th hot ng a bng tn,

a ch .

- Thc hin la chn kin trc my pht mm do.

- Thc hin phn cng x l tn hiu s.

- Xy dng kin trc phn mm v thc hin cc h thng anten thng minh

s dng cho SDR.

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Nguyen Thai Binh