thông tin di động

LI NI UNgy ny thng tin di ng l ngnh cng nghip vin thng pht trin nhanh nht vi con s thu bao t n 3,6 t tnh n cui nm 2008. Khi ngun t dch v thoi t tin cho mt s t ngi i xe, n nay vi s ng dng ngy cng rng ri cc thit b thng tin di ng th h ba, thng tin di ng c th cung cp nhiu hnh loi dch v i hi tc s liu cao cho ngi s dng k c cc chc nng camera, MP3 v PDA. Vi cc dch v i hi tc cao ngy cc tr nn ph bin ny, nhu cu 3G cng nh pht trin n ln 4G ngy cng tr nn cp thit. ITU a ra n tiu chun ho h thng thng tin di ng th h ba vi tn gi IMT-2000 t c cc mc tiu chnh sau y: Tc truy nhp cao m bo cc dch v bng rng nh truy nhp internet nhanh hoc cc ng dng a phng tin, do yu cu ngy cng tng v cc dch v ny. Linh hot 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 tm ph ca cc h thng thng tin di ng. Tng thch vi cc h thng thng tin di ng hin c m bo s pht trin lin tc ca thng tin di ng . Nhiu tiu chun cho h thng thng tin di ng th h ba IMT-2000 c xut, trong hai h thng WCDMA UMTS v cdma-2000 c ITU chp thun v c a vo hot ng. Cc h thng ny u s dng cng ngh CDMA iu ny cho php thc hin tiu chun ton th gii cho giao din v tuyn ca h thng thng tin ng th h ba. HSDPA (High Speech Downlink Packet Access: truy nhp gi ng xung tc cao) l mt m rng ca cc h thng 3G WCDMA UMTS c th cung cp tc ln n 10 Mbps trn ng xung. HSDPA l mt chun tng cng ca 3GPP-3G nhm tng dung lng ng xung bng cch thay th iu ch QPSK trong 3G UMTS bng 16QAM trong HSDPA. HSDPA hot ng trn c s kt hp ghp knh theo thi gian (TDM) vi ghp knh theo m v s dng thch ng ng truyn. N cng a ra mt knh iu khin ring m bo tc truyn dn s liu. Cc k thut tng t cng c p dng cho ng ln trong chun HSUPA (High Speech Uplink Packet Access). Hai cng ngh truy nhp HSDPA v HSUPA c gi chung l HSPA (High Speed Packet Data). lm cho cng ngh 3GPP UTRA/UTRAN mang tnh cnh tranh hn na (ch yu l cnh tranh vi cc cng ngh mi ca 3GPP2 v WiMAX), 3GPP quyt nh pht trin E-UTRA v EUTRAN (E: Elvolved k hiu cho pht trin) cn c gi l siu 3G (Super-3G) hay LTE (Long Term Evolution) m thc cht l giai on u 4G. Cng vic pht trin s tin hnh trong 10 nm v sau nh l s pht trin di hn (LTE: Long Term Evolution) ca cng ngh truy nhp v tuyn 3GPP. Trong giai on ny tc s liu t c 30-100Mbps vi bng thng 20MHz. Tip sau LTE, IMT-Adv (IMT tin tin) s c pht trin, y s l thi k pht trin ca 4G vi tc t 100 n 1000 Mbps v bng thng 100MHz. Hnh L.1 cho thy vin cnh ca thng tin di ng 4G v kh nng p ng tc chuyn ng v v tc truyn s liu.

TS. Nguyn Phm Anh Dng

1

B3G: Broad Band 3G: 3G bng rng WLAN: Wirless Local Area Network: Mng ni vng khng dy BWA: Broad Band Wirless Access: truy nhp khng dy bng rngHnh L.1. Vin cnh thng tin di ng 4G theo kh nng h tr tc chuyn ng v tc truyn s liu Hin nay tai Vit Nam bng tn I dnh cho WCDMA c chia l bn khe v c cp pht cho bn nh khai thc: Viettel, VMS, GPC, EVN+HT. Trong cc nm ti 3GWCDMA UMTS s c trin khai trn bng tn ny. Bi ging Gii thiu cng ngh 3G WCDMA UMTS nhm cung cp cc khi nim c bn v cng ngh 3G WCDMA UMTS cho cc cn b Tng Cng ty Vin Thng Qun i (Viettel). Bi ging bao gm bn chng. Chng u trnh by khi qut chung v s pht trin ca cc h thng thng tin di ng ln 4G, kin trc chung ca mt mng 3G; cc kin trc R3, R4, R5 v R6 ca mng thng tin di ng 3G WCDMA UMTS. Chng hai trnh by a truy nhp CDMA v cc k thut lin quan c p dng cho WCDMA. Chng ba gii thiu giao din v tuyn c WCDMA. Chng bn gii thiu cng ngh a truy nhp tc cao HSPA Cc chng ca ti liu ny u c kt cu theo modul hc vin d hc hc. Mi chng u c phn gii thiu chung, ni dung v tng kt.

H ng ngy 12 thng 6 nm 2009 Tc gi


2

MC LC

Chng 1...................................................................................5 TNG QUAN MNG 3G WCDMA UMTS........................................5 1.1. GII THIU CHUNG..........................................................5 1.2. L TRNH PHT TRIN THNG TIN DI NG LN 4G........5 1.3. KIN TRC CHUNG CA MT H THNG THNG TIN DI NG 3G................................................................................7 1.4. CHUYN MCH KNH (CS), CHUYN MCH GI (PS), DCH V CHUYN MCH KNH V DCH V CHUYN MCH GI......8 1.5. CC LOI LU LNG V DCH V C 3GWCDMA UMTS H TR ......................................................................11 1.6. KIN TRC 3G WCDMA UMTS R3 ...................................12 1.7. KIN TRC 3G WCDMA UMTS R4....................................19 1.8. KIN TRC 3G WCDMA UMTS R5 v R6..........................21 1.9. CHIN LC DCH CHUYN T GSM SANG UMTS..........23 1.10. CU HNH A L CA H THNG THNG TIN DI NG 3G......................................................................................... 26 1.11. TNG KT....................................................................29 Chng 2.................................................................................29 CNG NGH A TRUY NHP CA WCDMA...............................29 2.1. GII THIU CHUNG........................................................30 2.2. TRI PH V A TRUY NHP PHN CHIA THEO M........30 2.3. IU KHIN CNG SUT.................................................34 2.4. CHUYN GIAO TRONG H THNG CDMA........................34 2.5. MY THU PHN TP A NG HAY MY THU RAKE. . . .36 2.6. CC M TRI PH S DNG TRONG WCDMA.................37 2.7. TRI PH V IU CH NG LN..............................39 2.8. TRI PH V IU CH NG XUNG........................41 2.9. TNG KT......................................................................44 Chng 3.................................................................................45 GIAO DIN V TUYN CA WCDMA UMTS................................45 3.1. GII THIU CHUNG........................................................45 3.2. M U.........................................................................45 3.3. KIN TRC NGN XP GIAO THC CA GIAO DIN V TUYN WCDMA/FDD..............................................................46 3.4. CC THNG S LP VT L V QUY HOCH TN S.....48 3.5. CC KNH CA WCDMA.................................................51 3.6. CU TRC KNH VT L RING......................................59 3.7. S TNG QUT MY PHT V MY THU WCDMA.....60 3.8. PHN TP PHT............................................................61 3.9. IU KHIN CNG SUT TRONG WCDMA.......................63 3.10. CC KIU CHUYN GIAO V CC S KIN BO CO TRONG WCDMA..................................................................... 66TS. Nguyn Phm Anh Dng

3

3.11. CC THNG S MY THU V MY PHT V TUYN CA UE.........................................................................................68 3.12. AMR CODEC CHO W-CDMA ..........................................68 3.13. TNG KT....................................................................69 Chng 4.................................................................................71 TRUY NHP GI TC CAO (HSPA).......................................71 4.1. GII THIU CHUNG........................................................71 4.2. TNG QUAN TRUY NHP GI TC CAO (HSPA).........71 4.3. KIN TRC NGN XP GIAO THC GIAO DIN V TUYN HSPA CHO S LIU NGI S DNG...................................72 4.4. TRUY NHP GI TC CAO NG XUNG (HSDPA) 74 4.5. TRUY NHP GI TC CAO NG LN (HSUPA)......85 4.6. CHUYN GIAO TRONG HSDPA .......................................91 4.7. TNG KT......................................................................94 Thut ng v vit tt................................................................ 96Ti liu tham kho..100


4

Chng 1 TNG QUAN MNG 3G WCDMA UMTS1.1. GII THIU CHUNG 1.1.1. Mc ch chng Hiu l trnh pht trin thng tin di ng ln 4G Hiu c kin trc tng qut ca mt mng thng tin di ng 3G. Hiu cc kin trc mng 3G WCDMA UMTS: R3, R4 v R5 v chin lc chuyn dch GSM ln 3G UMTS

1.1.2. Cc ch c trnh by trong chng L trnh pht trin cc cng ngh thng tin di ng ln 4G Kin trc chung ca mt mng thng tin di ng 3G Cc khi nim v cc dch v chuyn mch knh v cc dch v chuyn mch gi Cc loi lu lng v cc loi dch v m 3G WCDMA UMTS c th h tr Kin trc 3G WCDMA UMTS qua cc pht hnh khc nhau: R3, R4, R5 v R6 Chin lc chuyn dch GSM ln 3G UMTS

1.1.3. Hng dn Hc k cc t liu c trnh by trong chng Tham kho thm cc ti liu tham kho cui ti liu

1.2. L TRNH PHT TRIN THNG TIN DI NG LN 4G

L trnh pht trin cc cng ngh thng tin di ng ln 4G c cho trn hnh 1.1 v l trnh nghin cu pht trin trong 3GPP c cho trn hnh 1.2..


5

AMPS: Advanced Mobile Phone System TACS: Total Access Communication System GSM: Global System for Mobile Telecommucations WCDMA: Wideband Code Division Multiple Access EVDO: Evolution Data Only IMT: International Mobile Telecommnications IEEE: Institute of Electrical and Electtronics Engineers WiFi: Wireless Fidelitity WiMAX: Worldwide Interoperability for Microwave Access LTE: Long Term Evolution UMB: Untra Mobile Broadband

Hnh 1.1. L trnh pht trin cc cng ngh thng tin di ng ln 4G

Hnh 1.2. Lch trnh nghin cu pht trin trong 3GPP Hnh 1.3. cho thy l trnh tng tc truyn s liu trong cc pht hnh ca 3GPP


6

Hnh 1.3. L trnh tng tc truyn s liu trong cc pht hnh ca 3GPP

1.3. KIN TRC CHUNG CA MT H THNG THNG TIN DI NG 3GMng thng tin di ng (TTD) 3G lc u s l mng kt hp gia cc vng chuyn mch gi (PS) v chuyn mch knh (CS) truyn s liu gi v ting. Cc trung tm chuyn mch gi s l cc chuyn mch s dng cng ngh ATM. Trn ng pht trin n mng ton IP, chuyn mch knh s dn c thay th bng chuyn mch gi. Cc dch v k c s liu ln thi gian thc (nh ting v video) cui cng s c truyn trn cng mt mi trng IP bng cc chuyn mch gi. Hnh 1.4 di y cho thy th d v mt kin trc tng qut ca TTD 3G kt hp c CS v PS trong mng li.

RAN: Radio Access Network: mng truy nhp v tuyn BTS: Base Transceiver Station: trm thu pht gc BSC: Base Station Controller: b iu khin trm gc RNC: Rado Network Controller: b iu khin trm gc CS: Circuit Switch: chuyn mch knh PS: Packet Switch: chuyn mch gi SMS: Short Message Servive: dch v nhn tin Server: my ch PSTN: Public Switched Telephone Network: mng in thoi chuyn mch cng cng PLMN: Public Land Mobile Network: mang di ng cng cng mt t

Hnh 1.4. Kin trc tng qut ca mt mng di ng kt hp c CS v PSTS. Nguyn Phm Anh Dng

7

Cc min chuyn mch knh (CS) v chuyn mch gi (PS) c th hin bng mt nhm cc n v chc nng lgic: trong thc hin thc t cc min chc nng ny c t vo cc thit b v cc nt vt l. Chng hn c th thc hin chc nng chuyn mch knh CS (MSC/GMSC) v chc nng chuyn mch gi (SGSN/GGSN) trong mt nt duy nht c mt h thng tch hp cho php chuyn mch v truyn dn cc kiu phng tin khc nhau: t lu lng ting n lu lng s liu dung lng ln. 3G UMTS (Universal Mobile Telecommunications System: H thng thng tin di ng ton cu) c th s dng hai kiu RAN. Kiu th nht s dng cng ngh a truy nhp WCDMA (Wide Band Code Devision Multiple Acces: a truy nhp phn chia theo m bng rng) c gi l UTRAN (UMTS Terrestrial Radio Network: mng truy nhp v tuyn mt t ca UMTS). Kiu th hai s dng cng ngh a truy nhp TDMA c gi l GERAN (GSM EDGE Radio Access Network: mng truy nhp v tuyn da trn cng ngh EDGE ca GSM). Ti liu ch xt cp n cng ngh duy nht trong UMTS c gi l 3G WCDMA UMTS

1.4. CHUYN MCH KNH (CS), CHUYN MCH GI (PS), DCH V CHUYN MCH KNH V DCH V CHUYN MCH GI.3G cung cp cc dch v chuyn mch knh nh ting, video v cc dch v chuyn mch gi ch yu truy nhp internet. Chuyn mch knh (CS: Circuit Switch) l s chuyn mch trong 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. Tm thi v n ch c duy tr trong thi gian cuc gi. Lin tc v n c cung cp lin tc mt ti nguyn nht nh (bng thng hay dung lng v cng sut) trong sut thi gian cuc gi. Dnh ring v kt ni ny v ti nguyn ch dnh ring cho cuc gi ny. Thit b chuyn mch s dng cho CS trong cc tng i ca TTD 2G thc hin chuyn mch knh trn trn c s ghp knh theo thi gian trong mi knh c tc 64 kbps v v th ph hp cho vic truyn cc ng dng lm vic ti tc c nh 64 kbps (chng hn ting c m ho PCM). Chuyn mch gi (PS: Packet Switch) l s chuyn mch 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. Chuyn mch gi cho php nhm tt c cc s liu ca nhiu kt ni khc nhau ph thuc vo ni dung, kiu hay cu trc s liu thnh cc gi c kch thc ph hp v truyn chng trn mt knh chia s. Vic nhm cc s liu cn truyn c thc hin bng ghp knh thng k vi n nh ti nguyn ng. Cc cng ngh s dng cho chuyn mch gi c th l Frame Relay, ATM hoc IP. Hnh 1.5. cho thy cu trc ca CS v PS.


8

Hnh 1.5. Chuyn mch knh (CS) v chuyn mch gi (PS). Dch v chuyn mch knh (CS Service) l dch v trong 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 tuy nhin phi tr tin cho ton b thi gian ny d c truyn tin hay khng. Dch v chuyn mch knh c th c thc hin trn chuyn mch knh (CS) hoc chuyn mch gi (PS). Thng thng dch v ny c p dng cho cc dch v thi gian thc (thoi). Dch v chuyn mch gi (PS Service) l dch v trong 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. Dch v chuyn mch gi ch c th c thc hin trn chuyn mch gi (PS). Dch v ny rt rt ph hp cho cc dch v phi thi gian thc (truyn s liu), tuy nhin nh s pht trin ca cng ngh dch v ny cng c p dng cho cc dch v thi gian thc (VoIP). Chuyn mch gi c th thc hin trn c s ATM hoc IP. ATM (Asynchronous Transfer Mode: ch truyn d b) l cng ngh thc hin phn chia thng tin cn pht thnh cc t bo 53 byte truyn dn v chuyn mch. Mt t bo ATM gm 5 byte tiu (c cha thng tin nh tuyn) v 48 byte ti tin (cha s liu ca ngi s dng). Thit b chuyn mch ATM cho php chuyn mch nhanh trn c s chuyn mch phn cng tham chun theo thng tin nh tuyn tiu m khng thc hin pht hin li trong tng t bo. Thng tin nh tuyn trong tiu gm: ng dn o (VP) v knh o (VC). iu khin kt ni bng VC (tng ng vi knh ca ngi s dng) v VP (l mt b cc VC) cho php khai thc v qun l c kh nng m rng v c linh hot cao. Thng thng VP c thit lp trn c s s liu ca h thng ti thi im xy dng mng. Vic s dng ATM trong mng li cho ta nhiu ci li: c th qun l lu lng kt hp vi RAN, cho php thc hin cc chc nng CS v PS trong cng mt kin trc v thc hin khai thc cng nh iu khin cht lng lin kt.


9

Chuyn mch hay Router IP (Internet Protocol) cng l mt cng ngh thc hin phn chia thng tin pht thnh cc gi c gi l ti tin (Payload). Sau mi gi c gn mt tiu cha cc thng tin a ch cn thit cho chuyn mch. Trong thng tin di ng do v tr ca u cui di ng thay i nn cn phi c thm tiu b sung nh tuyn theo v tr hin thi ca my di ng. Qu trnh nh tuyn ny c gi l truyn ng hm (Tunnel). C hai c ch thc hin iu ny: MIP (Mobile IP: IP di ng) v GTP (GPRS Tunnel Protocol: giao thc ng hm GPRS). Tunnel l mt ng truyn m ti u vo ca n gi IP c ng bao vo mt tiu mang a ch ni nhn (trong trng hp ny l a ch hin thi ca my di ng) v ti u ra gi IP c tho bao bng cch loi b tiu bc ngoi (hnh 1.6).

Hnh 1.6. ng bao v tho bao cho gi IP trong qu trnh truyn tunnel Hnh 1.7 cho thy qu trnh nh tuyn tunnel (chuyn mch tunnel) trong h thng 3G UMTS t tng i gi cng (GGSN) cho mt my di ng (UE) khi n chuyn t vng phc v ca mt tng i gi ni ht (SGSN1) ny sang mt vng phc v ca mt tng i gi ni ht khc (SGSN2) thng qua giao thc GTP.

Hnh 1.7. Thit lp kt ni tunnel trong chuyn mch tunnel V 3G WCDMA UMTS c pht trin t nhng nm 1999 khi m ATM l cng ngh chuyn mch gi cn ng tr nn cc tiu chun cng c xy dng trn cng ngh ny. Tuy nhin hin nay v tng lai mng vin thng s c xy dng trn c s internet v th cc chuyn mch gi s l chuyn mch hoc router IP.


10

1.5. CC LOI LU LNG V DCH V C 3GWCDMA UMTS H TRV TTD 3G cho php truyn dn nhanh hn, nn truy nhp Internet v lu lng thng tin s liu khc s pht trin nhanh. Ngoi ra TTD 3G cng c s dng cho cc dch v ting. Ni chung TTD 3G h tr cc dch v tryn thng a phng tin. V th mi kiu lu lng cn m bo mt mc QoS nht nh tu theo ng dng ca dch v. QoS W-CDMA c phn loi nh sau: Loi hi thoi (Conversational, rt): Thng tin tng tc yu cu tr nh (thoi chng hn). Loi lung (Streaming, rt): Thng tin mt chiu i hi dch v lung vi tr nh (phn phi truyn hnh thi gian thc chng hn: Video Streaming) Loi tng tc (Interactive, nrt): i hi tr li trong mt thi gian nht nh v t l li thp (trnh duyt Web, truy nhp server chng hn). Loi nn (Background, nrt): i hi cc dch v n lc nht c thc hin trn nn c s (e-mail, ti xung file: Video Download) Mi trng hot ng ca 3WCDMA UMTS c chia thnh bn vng vi cc tc bit Rb phc v nh sau: Vng 1: trong nh, pico, Rb 2Mbps Vng 2: thnh ph, micro, Rb 384 kbps Vng 2: ngoi , macro, Rb 144 kbps Vng 4: Ton cu, Rb = 12,2 kbps C th tng kt cc dch v do 3GWCDMA UMTS cung cp bng 1.1. Bng 1.1. Phn loi cc dch v 3GWDCMA UMTS Kiu Phn loi Dch v chi tit

Dch v di Dch v di ng ng Dch v thng tin nh v Dch v m thanh

Di ng u cui/di ng c nhn/di ng dch v - Theo di di ng/ theo di di ng thng minh - Dch v m thanh cht lng cao (16-64 kbps) - Dch v truyn thanh AM (32-64 kbps) - Dch v truyn thanh FM (64-384 kbps) Dch v Dch v s liu - Dch v s liu tc trung bnh (64-144 vin thng kbps) - Dch v s liu tc tng i cao (144 kbps- 2Mbps) - Dch v s liu tc cao ( 2Mbps) Dch v a - Dch v Video (384 kbps)TS. Nguyn Phm Anh Dng

11

Kiu

Dch v chi tit - Dch v hnh chuyn ng (384kbps- 2 Mbps) - Dch v hnh chuyn ng thi gian thc ( 2 Mbps) Dch v Internet Dch v truy nhp Web (384 kbps-2Mbps) n gin Dch v Dch v Internet Dch v Internet (384 kbps-2Mbps) Internet thi gian thc Dch v internet Dch v Website a phng tin thi gian thc a phng tin ( 2Mbps) 3G WCDMA UMTS c xy dng theo ba pht hnh chnh c gi l R3, R4, R5. Trong mng li R3 v R4 bao gm hai min: min CS (Circuit Switch: chuyn mch knh) v min PS (Packet Switch: chuyn mch gi). Vic kt hp ny ph hp cho giai on u khi PS cha p ng tt cc dch v thi gian thc nh thoi v hnh nh. Khi ny min CS s m nhim cc dch v thoi cn s liu c truyn trn min PS. R4 pht trin hn R3 ch min CS chuyn sang chuyn mch mm v th ton b mng truyn ti gia cc nt chuyn mch u trn IP. Di y ta xt ba kin trc 3G WCDMA UMTS ni trn.

Phn loi phng tin

1.6. KIN TRC 3G WCDMA UMTS R3WCDMA UMTS R3 h tr c kt ni chuyn mch knh ln chuyn mch gi: n 384 Mbps trong min CS v 2Mbps trong min PS. Cc kt ni tc cao ny m bo cung cp mt tp cc dich v mi cho ngi s dng di ng ging nh trong cc mng in thoi c nh v Internet. Cc dch v ny gm: in thoi c hnh (Hi ngh video), m thanh cht lng cao (CD) v tc truyn cao ti u cui. Mt tnh nng khc cng c a ra cng vi GPRS l "lun lun kt ni" n Internet. UMTS cng cung cp thng tin v tr tt hn v v th h tr tt hn cc dch v da trn v tr. Mt mng UMTS bao gm ba phn: thit b di ng (UE: User Equipment), mng truy nhp v tuyn mt t UMTS (UTRAN: UMTS Terrestrial Radio Network), mng li (CN: Core Network) (xem hnh 1.8). UE bao gm ba thit b: thit b u cui (TE), thit b di ng (ME) v module nhn dng thu bao UMTS (USIM: UMTS Subscriber Identity Module). UTRAN gm cc h thng mng v tuyn (RNS: Radio Network System) v mi RNS bao gm RNC (Radio Network Controller: b iu khin mng v tuyn) v cc nt B ni vi n. Mng li CN bao gm min chuyn mch knh, chuyn mch gi v HE (Home Environment: Mi trng nh). HE bao gm cc c s d liu: AuC (Authentication Center: Trung tm nhn thc), HLR (Home Location Register: B ghi nh v thng tr) v EIR (Equipment Identity Register: B ghi nhn dng thit b).


12

Hnh 1.8. Kin trc 3G WCDMA UMTS R3

1.6.1. Thit b ngi s dng (UE)UE (User Equipment: thit b ngi s dng) l u cui mng UMTS ca ngi s dng. C th ni y l phn h thng c nhiu thit b nht v s pht trin ca n s nh hng ln ln cc ng dng v cc dch v kh dng. Gi thnh gim nhanh chng s to iu kin cho ngi s dng mua thit b ca UMTS. iu ny t c nh tiu chun ha giao din v tuyn v ci t mi tr tu ti cc card thng minh.

1.6.1.1. Cc u cui (TE)V my u cui by gi khng ch n thun dnh cho in thoi m cn cung cp cc dch v s liu mi, nn tn ca n c chuyn thnh u cui. Cc nh sn xut chnh a ra rt nhiu u cui da trn cc khi nim mi, nhng trong thc t ch mt s t l c a vo sn xut. Mc d cc u cui d kin khc nhau v kch thc v thit k, tt c chng u c mn hnh ln v t phm hn so vi 2G. L do chnh l tng cng s dng u cui cho nhiu dch v s liu hn v v th u cui tr thnh t hp ca my thoi di ng, modem v my tnh bn tay. u cui h tr hai giao din. Giao din Uu nh ngha lin kt v tuyn (giao din WCDMA). N m nhim ton b kt ni vt l vi mng UMTS. Giao din th hai l giao din Cu gia UMTS IC card (UICC) v u cui. Giao din ny tun theo tiu chun cho cc card thng minh. Mc d cc nh sn xut u cui c rt nhiu tng v thit b, h phi tun theo mt tp ti thiu cc nh ngha tiu chun cc ngi s dng bng cc u cui khc nhau c th truy nhp n mt s cc chc nng c s theo cng mt cch. Cc tiu chun ny gm: Bn phm (cc phm vt l hay cc phm o trn mn hnh) ng k mt khu mi Thay i m PIN Gii chn PIN/PIN2 (PUK)TS. Nguyn Phm Anh Dng

13

Trnh by IMEI iu khin cuc gi

Cc phn cn li ca giao din s dnh ring cho nh thit k v ngi s dng s chn cho mnh u cui da trn hai tiu chun (nu xu th 2G cn ko di) l thit k v giao din. Giao din l kt hp ca kch c v thng tin do mn hnh cung cp (mn hnh nt chm), cc phm v menu.

1.6.1.2. UICCUMTS IC card l mt card thng minh. iu m ta quan tm n n l dung lng nh v tc b x l do n cung cp. ng dng USIM chy trn UICC.

1.6.1.3. USIMTrong h thng GSM, SIM card lu gi thng tin c nhn (ng k thu bao) ci cng trn card. iu ny thay i trong UMTS, Modul nhn dng thu bao UMTS c ci nh mt ng dng trn UICC. iu ny cho php lu nhiu ng dng hn v nhiu ch k (kha) in t hn cng vi USIM cho cc mc ch khc (cc m truy nhp giao dch ngn hng an ninh). Ngoi ra c th c nhiu USIM trn cng mt UICC h tr truy nhp n nhiu mng. USIM cha cc hm v s liu cn nhn dng v nhn thc thu bao trong mng UMTS. N c th lu c bn sao h s ca thu bao. Ngi s dng phi t mnh nhn thc i vi USIM bng cch nhp m PIN. iu ny m bo rng ch ngi s dng ch thc mi c truy nhp mng UMTS. Mng s ch cung cp cc dch v cho ngi no s dng u cui da trn nhn dng USIM c ng k.

1.6.2. Mng truy nhp v tuyn UMTSUTRAN (UMTS Terrestrial Radio Access Network: Mng truy nhp v tuyn mt t UMTS) l lin kt gia ngi s dng v CN. N gm cc phn t m bo cc cuc truyn thng UMTS trn v tuyn v iu khin chng. UTRAN c nh ngha gia hai giao din. Giao din Iu gia UTRAN v CN, gm hai phn: IuPS cho min chuyn mch gi v IuCS cho min chuyn mch knh; giao din Uu gia UTRAN v thit b ngi s dng. Gia hai giao din ny l hai nt, RNC v nt B.

1.6.2.1. RNCRNC (Radio Network Controller) chu trch nhim cho mt hay nhiu trm gc v iu khin cc ti nguyn ca chng. y cng chnh l im truy nhp dch v m UTRAN cung cp cho CN. N c ni n CN bng hai kt ni, mt cho min chuyn mch gi (n GPRS) v mt n min chuyn mch knh (MSC).TS. Nguyn Phm Anh Dng

14

Mt nhim v quan trng na ca RNC l bo v s b mt v ton vn. Sau th tc nhn thc v tha thun kha, cc kho bo mt v ton vn c t vo RNC. Sau cc kha ny c s dng bi cc hm an ninh f8 v f9. RNC c nhiu chc nng logic ty thuc vo vic n phc v nt no. Ngi s dng c kt ni vo mt RNC phc v (SRNC: Serving RNC). Khi ngi s dng chuyn vng n mt RNC khc nhng vn kt ni vi RNC c, mt RNC tri (DRNC: Drift RNC) s cung cp ti nguyn v tuyn cho ngi s dng, nhng RNC phc v vn qun l kt ni ca ngi s dng n CN. Vai tr logic ca SRNC v DRNC c m t trn hnh 1.9. Khi UE trong chuyn giao mm gia cc RNC, tn ti nhiu kt ni qua Iub v c t nht mt kt ni qua Iur. Ch mt trong s cc RNC ny (SRNC) l m bo giao din Iu kt ni vi mng li cn cc RNC khc (DRNC) ch lm nhim v nh tuyn thng tin gia cc Iub v Iur. Chc nng cui cng ca RNC l RNC iu khin (CRNC: Control RNC). Mi nt B c mt RNC iu khin chu trch nhim cho cc ti nguyn v tuyn ca n.

Hnh 1.9. Vai tr logic ca SRNC v DRNC

1.6.2.2. Nt BTrong UMTS trm gc c gi l nt B v nhim v ca n l thc hin kt ni v tuyn vt l gia u cui vi n. N nhn tn hiu trn giao din Iub t RNC v chuyn n vo tn hiu v tuyn trn giao din Uu. N cng thc hin mt s thao tc qun l ti nguyn v tuyn c s nh "iu khin cng sut vng trong". Tnh nng ny phng nga vn gn xa; ngha l nu tt c cc u cui u pht cng mt cng sut, th cc u cui gn nt B nht s che lp tn hiu t cc u cui xa. Nt B kim tra cng sut thu t cc u cui khc nhau v thng bo cho chng gim cng sut hoc tng cng sut sao cho nt B lun thu c cng sut nh nhau t tt c cc u cui.

1.6.3. Mng liMng li (CN) c chia thnh ba phn, min PS, min CS v HE. Min PS m bo cc dch v s liu cho ngi s dng bng cc kt ni n Internet v cc mng s liu khc v min CS m bo cc dch v in thoi n cc mng khc bng cc kt ni TDM. Cc nt B trong CN c kt ni vi nhau bng ng trc ca nh khai thc, thng s dng cc cng ngh mng tc cao nh ATM v IP. Mng ng trc trong min CS s dng TDM cn trong min PS s dng IP.TS. Nguyn Phm Anh Dng

15

1.6.3.1. SGSNSGSN (SGSN: Serving GPRS Support Node: nt h tr GPRS phc v) l nt chnh ca min chuyn mch gi. N ni n UTRAN thng qua giao din IuPS v n GGSN thng quan giao din Gn. SGSN chu trch nhim cho tt c kt ni PS ca tt c cc thu bao. N lu hai kiu d liu thu bao: thng tin ng k thu bao v thng tin v tr thu bao. S liu thu bao lu trong SGSN gm: IMSI (International Mobile Subsscriber Identity: s nhn dng thu bao di ng quc t) Cc nhn dng tm thi gi (P-TMSI: Packet- Temporary Mobile Subscriber Identity: s nhn dng thu bao di ng tm thi gi) Cc a ch PDP (Packet Data Protocol: Giao thc s liu gi) S liu v tr lu trn SGSN: Vng nh tuyn thu bao (RA: Routing Area) S VLR Cc a ch GGSN ca tng GGSN c kt ni tch cc

1.6.3.2. GGSNGGSN (Gateway GPRS Support Node: Nt h tr GPRS cng) l mt SGSN kt ni vi cc mng s liu khc. Tt c cc cuc truyn thng s liu t thu bao n cc mng ngoi u qua GGSN. Cng nh SGSN, n lu c hai kiu s liu: thng tin thu bao v thng tin v tr. S liu thu bao lu trong GGSN: IMSI Cc a ch PDP S liu v tr lu trong GGSN: a ch SGSN hin thu bao ang ni n GGSN ni n Internet thng qua giao din Gi v n BG thng qua Gp.

1.6.3.3. BGBG (Border Gatway: Cng bin gii) l mt cng gia min PS ca PLMN vi cc mng khc. Chc nng ca nt ny ging nh tng la ca Internet: m bo mng an ninh chng li cc tn cng bn ngoi.


16

1.6.3.4. VLRVLR (Visitor Location Register: b ghi nh v tm tr) l bn sao ca HLR cho mng phc v (SN: Serving Network). D liu thu bao cn thit cung cp cc dch v thu bao c copy t HLR v lu y. C MSC v SGSN u c VLR ni vi chng. S liu sau y c lu trong VLR: IMSI MSISDN TMSI (nu c) LA hin thi ca thu bao MSC/SGSN hin thi m thu bao ni n Ngoi ra VLR c th lu gi thng tin v cc dch v m thu bao c cung cp. C SGSN v MSC u c thc hin trn cng mt nt vt l vi VLR v th c gi l VLR/SGSN v VLR/MSC.

1.6.3.5. MSCMSC thc hin cc kt ni CS gia u cui v mng. N thc hin cc chc nng bo hiu v chuyn mch cho cc thu bao trong vng qun l ca mnh. Chc nng ca MSC trong UMTS ging chc nng MSC trong GSM, nhng n c nhiu kh nng hn. Cc kt ni CS c thc hin trn giao din CS gia UTRAN v MSC. Cc MSC c ni n cc mng ngoi qua GMSC.

1.6.3.6. GMSCGMSC c th l mt trong s cc MSC. GMSC chu trch nhim thc hin cc chc nng nh tuyn n vng c MS. Khi mng ngoi tm cch kt ni n PLMN ca mt nh khai thc, GMSC nhn yu cu thit lp kt ni v hi HLR v MSC hin thi qun l MS.

1.6.3.7. Mi trng nhMi trng nh (HE: Home Environment) lu cc h s thu bao ca hng khai thc. N cng cung cp cho cc mng phc v (SN: Serving Network) cc thng tin v thu bao v v cc cn thit nhn thc ngi s dng v tnh cc cho cc dch v cung cp. Tt c cc dch v c cung cp v cc dch v b cm u c lit k y.


17

B ghi nh v thng tr (HLR) HLR l mt c s d liu c nhim v qun l cc thu bao di ng. Mt mng di ng c th cha nhiu HLR ty thuc vo s lng thu bao, dung lng ca tng HLR v t chc bn trong mng. C s d liu ny cha IMSI (International Mobile Subsscriber Identity: s nhn dng thu bao di ng quc t), t nht mt MSISDN (Mobile Station ISDN: s thu bao c trong danh b in thoi) v t nht mt a ch PDP (Packet Data Protocol: Giao thc s liu gi). C IMSI v MSISDN c th s dng lm kho truy nhp n cc thng tin c lu khc. nh tuyn v tnh cc cc cuc gi, HLR cn lu gi thng tin v SGSN v VLR no hin ang chu trch nhim thu bao. Cc dch v khc nh chuyn hng cuc gi, tc s liu v th thoi cng c trong danh sch cng vi cc hn ch dch v nh cc hn ch chuyn mng. HLR v AuC l hai nt mng logic, nhng thng c thc hin trong cng mt nt vt l. HLR lu gi mi thng tin v ngi s dng v ng k thu bao. Nh: thng tin tnh cc, cc dch v no c cung cp v cc dch v no b t chi v thng tin chuyn hng cuc gi. Nhng thng tin quan trng nht l hin VLR v SGSN no ang ph trch ngi s dng. Trung tm nhn thc (AuC) AUC (Authentication Center) lu gi ton b s liu cn thit nhn thc, mt m ha v bo v s ton vn thng tin cho ngi s dng. N lin kt vi HLR v c thc hin cng vi HLR trong cng mt nt vt l. Tuy nhin cn m bo rng AuC ch cung cp thng tin v cc vect nhn thc (AV: Authetication Vector) cho HLR. AuC lu gi kha b mt chia s K cho tng thu bao cng vi tt c cc hm to kha t f0 n f5. N to ra cc AV, c trong thi gian thc khi SGSN/VLR yu cu hay khi ti x l thp, ln cc AV d tr. B ghi nhn dng thit b (EIR) EIR (Equipment Identity Register) chu trch nhim lu cc s nhn dng thit b di ng quc t (IMEI: International Mobile Equipment Identity). y l s nhn dng duy nht cho thit b u cui. C s d liu ny c chia thnh ba danh mc: danh mc trng, xm v en. Danh mc trng cha cc s IMEI c php truy nhp mng. Danh mc xm cha IMEI ca cc u cui ang b theo di cn danh mc en cha cc s IMEI ca cc u cui b cm truy nhp mng. Khi mt u cui c thng bo l b mt cp, IMEI ca n s b t vo danh mc en v th n b cm truy nhp mng. Danh mc ny cng c th c s dng cm cc seri my c bit khng c truy nhp mng khi chng khng hot ng theo tiu chun.

1.6.4. Cc mng ngoiCc mng ngoi khng phi l b phn ca h thng UMTS, nhng chng cn thit m bo truyn thng gia cc nh khai thc. Cc mng ngoi c th l ccTS. Nguyn Phm Anh Dng

18

mng in thoi nh: PLMN (Public Land Mobile Network: mng di ng mt t cng cng), PSTN (Public Switched Telephone Network: Mng in thoi chuyn mch cng cng), ISDN hay cc mng s liu nh Internet. Min PS kt ni n cc mng s liu cn min CS ni n cc mng in thoi.

1.6.5. Cc giao dinVai tr cc cc nt khc nhau ca mng ch c nh ngha thng qua cc giao din khc nhau. Cc giao din ny c nh ngha cht ch cc nh sn xut c th kt ni cc phn cng khc nhau ca h. Giao din Cu. Giao din Cu l giao din chun cho cc card thng minh. Trong UE y l ni kt ni gia USIM v UE Giao din Uu. Giao din Uu l giao din v tuyn ca WCDMA trong UMTS. y l giao din m qua UE truy nhp vo phn c nh ca mng. Giao din ny nm gia nt B v u cui. Giao din Iu. Giao din Iu kt ni UTRAN v CN. N gm hai phn, IuPS cho min chuyn mch gi, IuCS cho min chuyn mch knh. CN c th kt ni n nhiu UTRAN cho c giao din IuCS v IuPS. Nhng mt UTRAN ch c th kt ni n mt im truy nhp CN. Giao din Iur. y l giao din RNC-RNC. Ban u c thit k m bo chuyn giao mm gia cc RNC, nhng trong qu trnh pht trin nhiu tnh nng mi c b sung. Giao din ny m bo bn tnh nng ni bt sau: 1. Di ng gia cc RNC 2. Lu thng knh ring 3. Lu thng knh chung 4. Qun l ti nguyn ton cc

Giao din Iub. Giao din Iub ni nt B v RNC. Khc vi GSM y l giaodin m.

1.7. KIN TRC 3G WCDMA UMTS R4Hnh 1.10 cho thy kin trc c s ca 3G UMTS R4. S khc nhau c bn gia R3 v R4 l ch khi ny mng li l mng phn b v chuyn mch mm. Thay cho vic c cc MSC chuyn mch knh truyn thng nh kin trc trc, kin trc chuyn mch phn b v chuyn mch mm c a vo. V cn bn, MSC c chia thnh MSC server v cng cc phng tin (MGW: Media Gateway). MSC cha tt c cc phn mm iu khin cuc gi, qun l di ng c mt MSC tiu chun. Tuy nhin n khng cha ma trn chuyn mch. Ma trn chuyn mch nm trong MGW c MSC Server iu khin v c th t xa MSC Server.


19

Hnh 1.10. Kin trc mng phn b ca pht hnh 3GPP R4 Bo hiu iu khin cc cuc gi chuyn mch knh c thc hin gia RNC v MSC Server. ng truyn cho cc cuc gi chuyn mch knh c thc hin gia RNC v MGW. Thng thng MGW nhn cc cuc gi t RNC v nh tuyn cc cuc gi ny n ni nhn trn cc ng trc gi. Trong nhiu trng hp ng trc gi s dng Giao thc truyn ti thi gian thc (RTP: Real Time Transport Protocol) trn Giao thc Internet (IP). T hnh 1.10 ta thy lu lng s liu gi t RNC i qua SGSN v t SGSN n GGSN trn mng ng trc IP. C s liu v ting u c th s dng truyn ti IP bn trong mng li. y l mng truyn ti hon ton IP. Ti ni m mt cuc gi cn chuyn n mt mng khc, PSTN chng hn, s c mt cng cc phng tin khc (MGW) c iu khin bi MSC Server cng (GMSC server). MGW ny s chuyn ting thoi c ng gi thnh PCM tiu chun a n PSTN. Nh vy chuyn i m ch cn thc hin ti im ny. th d, ta gi thit rng nu ting giao din v tuyn c truyn ti tc 12,2 kbps, th tc ny ch phi chuyn vo 64 kbps MGW giao tip vi PSTN. Truyn ti kiu ny cho php tit kim ng k rng bng tn nht l khi cc MGW cch xa nhau. Giao thc iu khin gia MSC Server hoc GMSC Server vi MGW l giao thc ITU H.248. Giao thc ny c ITU v IETF cng tc pht trin. N c tn l iu khin cng cc phng tin (MEGACO: Media Gateway Control). Giao thc iu khin cuc gi gia MSC Server v GMSC Server c th l mt giao thc iu khin cuc gi bt k. 3GPP ngh s dng (khng bt buc) giao thc iu khin cuc gi c lp vt mang (BICC: Bearer Independent Call Control) c xy dng trn c s khuyn ngh Q.1902 ca ITU.


20

Trong nhiu trng hp MSC Server h tr c cc chc nng ca GMSC Server. Ngoi ra MGW c kh nng giao din vi c RAN v PSTN. Khi ny cuc gi n hoc t PSTN c th chuyn ni ht, nh vy c th tit kim ng k u t. lm th d ta xt trng hp khi mt RNC c t ti thnh ph A v c iu khin bi mt MSC t ti thnh ph B. Gi s thu bao thnh ph A thc hin cuc gi ni ht. Nu khng c cu trc phn b, cuc gi cn chuyn t thnh ph A n thnh ph B (ni c MSC) u ni vi thu bao PSTN ti chnh thnh ph A. Vi cu trc phn b, cuc gi c th c iu khin ti MSC Server thnh ph B nhng ng truyn cc phng tin thc t c th vn thnh ph A, nh vy gim ng k yu cu truyn dn v gi thnh khai thc mng. T hnh 1.10 ta cng thy rng HLR cng c th c gi l Server thu bao ti nh (HSS: Home Subscriber Server). HSS v HLR c chc nng tng ng, ngoi tr giao din vi HSS l giao din trn c s truyn ti gi (IP chng hn) trong khi HLR s dng giao din trn c s bo hiu s 7. Ngoi ra cn c cc giao din (khng c trn hnh v) gia SGSN vi HLR/HSS v gia GGSN vi HLR/HSS. Rt nhiu giao thc c s dng bn trong mng li l cc giao thc trn c s gi s dng hoc IP hoc ATM. Tuy nhin mng phi giao din vi cc mng truyn thng qua vic s dng cc cng cc phng tin. Ngoi ra mng cng phi giao din vi cc mng SS7 tiu chun. Giao din ny c thc hin thng qua cng SS7 (SS7 GW). y l cng m mt pha n h tr truyn ti bn tin SS7 trn ng truyn ti SS7 tiu chun, pha kia n truyn ti cc bn tin ng dng SS7 trn mng gi (IP chng hn). Cc thc th nh MSC Server, GMSC Server v HSS lin lc vi cng SS7 bng cch s dng cc giao thc truyn ti c thit k c bit mang cc bn tin SS7 mng IP. B giao thc ny c gi l Sigtran.

1.8. KIN TRC 3G WCDMA UMTS R5 v R6Bc pht trin tip theo ca UMTS l a ra kin trc mng a phng tin IP (hnh 1.11). Bc pht trin ny th hin s thay i ton b m hnh cuc gi. y c ting v s liu c x l ging nhau trn ton b ng truyn t u cui ca ngi s dng n ni nhn cui cng. C th coi kin trc ny l s hi t ton din ca ting v s liu.


21

Hnh 1.11. Kin trc mng 3GPP R5 v R6 im mi ca R5 v R6 l n a ra mt min mi c gi l phn h a phng tin IP (IMS: IP Multimedia Subsystem). y l mt min mng IP c thit k h tr cc dch v a phng tin thi gian thc IP. T hnh 1.11 ta thy ting v s liu khng cn cc giao din cch bit; ch c mt giao din Iu duy nht mang tt c phng tin. Trong mng li giao din ny kt cui ti SGSN v khng c MGW ring. Phn h a phng tin IP (IMS) cha cc phn t sau: Chc nng iu khin trng thi kt ni (CSCF: Connection State Control Function), Chc nng ti nguyn a phng tin (MRF: Multimedia Resource Function), chc nng iu khin cng cc phng tin (MGCF: Media Gateway Control Function), Cng bo hiu truyn ti (T-SGW: Transport Signalling Gateway) v Cng bo hiu chuyn mng (R-SGW: Roaming Signalling Gateway). Mt nt quan trng ca kin trc ton IP l thit b ca ngi s dng c tng cng rt nhiu. Nhiu phn mm c ci t UE. Trong thc t, UE h tr giao thc khi u phin (SIP: Session Initiation Protocol). UE tr thnh mt tc nhn ca ngi s dng SIP. Nh vy, UE c kh nng iu khin cc dch v ln hn trc rt nhiu. CSCF qun l vic thit lp , duy tr v gii phng cc phin a phng tin n v t ngi s dng. N bao gm cc chc nng nh: phin dch v nh tuyn. CSCF hot ng nh mt i din Server /h tch vin. SGSN v GGSN l cc phin bn tng cng ca cc nt c s dng GPRS v UMTS R3 v R4. im khc nhau duy nht l ch cc nt ny khng ch h tr dch v s liu gi m c dch v chuyn mch knh (ting chng hn). V th cn h tr cc kh nng cht lng dch v (QoS) hoc bn trong SGSN v GGSN hoc t nht cc Router kt ni trc tip vi chng.TS. Nguyn Phm Anh Dng

22

Chc nng ti nguyn a phng tin (MRF) l chc nng lp cu hi nghi c s dng h tr cc tnh nng nh t chc cuc gi nhiu pha v dch v hi ngh . Cng bo hiu truyn ti (T-SGW) l mt cng bo hiu SS7 m bo tng tc SS7 vi cc mng tiu chun ngoi nh PSTN. T-SGW h tr cc giao thc Sigtran. Cng bo hiu chuyn mng (R-SGW) l mt nt m bo tng tc bo hiu vi cc mng di ng hin c s dng SS7 tiu chun. Trong nhiu trng hp TSGW v R-SGW cng tn ti trn cng mt nn tng. MGW thc hin tng tc vi cc mng ngoi mc ng truyn a phng tin. MGW kin trc mng ca UMTS R5 c chc nng ging nh R4. MGW c iu khin bi Chc nng cng iu khin cc phng tin (MGCF). Giao thc iu khin gia cc thc th ny l ITU-T H.248. MGCF cng lin lc vi CSCF. Giao thc c chn cho giao din ny l SIP. Tuy nhin c th nhiu nh khai thc vn s dng n kt hp vi cc min chuyn mch knh trong R3 v R4. iu ny cho php chuyn i dn dn t cc phin bn R3 v R4 sang R5. Mt s cc cuc gi thoi c th vn s dng min CS mt s cc dch v khc chng hn video c th c thc hin qua R5 IMS. Cu hnh lai ghp c th hin trn hnh 1.12.

Hnh 1.12. Chuyn i dn t R4 sang R5

1.9. CHIN LC DCH CHUYN T GSM SANG UMTSTrong phn ny ta s xt chin lc dch chuyn t GSM sang UMTS ca hng Alcatel. Alcatel d kin pht trin RAN t GSM ln 3G UMTS theo ba pht hnh: 3GR1, 3GR2 v 3GR3. Vi mi pht hnh, cc sn phm mi v cc tnh nng mi c a ra.

1.9.1. 3GR1 : Kin trc mng UMTS chng lnPht hnh 3GP1 da trn pht hnh ca 3GPP vo thng 3 v cc c t k thut vo thng 6 nm 2000. Pht hnh u ca 3GR1 ch h tr UTRA-FDD v sTS. Nguyn Phm Anh Dng

23

c trin khai chng ln ln GSM. Chin lc dch chuyn t GSM sang UMTS pht hnh 3GR1 c chia thnh ba giai on c k hiu l R1.1, R1.2 v R1.3 (R: Release: pht hnh). Trong cc pht hnh ny cc phn cng v cc tnh nng mi c a ra. Cc nt B c gi l MBS (Multistandard Base Station: trm gc a tiu chun). Tuy nhin MBS V1 ch n thun l nt B, ch MBS V2 mi thc s a tiu chun v cha cc chc nng ca c nt B v BTS trong cng mt hp my. Tng t RNC V2 v OMC-R V2 c a ra phc v cho c UMTS v GSM. Hnh 1.13 cho thy kin trc ng tn ti GSM v UMTS c pht trin trong giai on trin khai UMTS ban u (3GR1.1).

Hnh 1.13. Kin trc ng tn ti GSM v UMTS (pht hnh 3GR1.1)

1.9.2. 3GR2 : Tch hp cc mng UMTS v GSMTrong giai on trin khai UMTS th hai s tch hp u tin gia hai mng s c thc hin bng cch a ra cc thit b a tiu chun nh: Nt B kt hp BTS (MBS V2) v RNC kt hp BSC (RNC V2). Cc chc nng khai thc v bo dng mng v tuyn cng c th c thc hin chung bi cng mt OMC-R (V2). Hnh 1.14 m t kin trc mng RAN tch hp ca giai on hai.


24

Hnh 1.14. Kin trc mng RAN tch hp pht hnh 3GR2 (R2.1).

1.9.3. 3GR3 : Kin trc RAN thng nhtTrong kin trc RAN ca pht hnh ny c xy dng trn c s pht hnh R5 vo thng 9 nm 2000 ca 3GPP. Trong pht hnh ny RAN chung cho c h thng UMTS v GSM. C UTRA-FDD v UTRA-TDD u c h tr. Giao thc truyn ti c thng nht cho GSM, E-GPRS v UMTS, ngoi ra c th ATM kt hp IP. GERAN (GSM/EDGE RAN) cng s c h tr bi pht hnh ny ca mng. Kin trc RAN ca 3GR1.3 c th hin trn hnh 1.15.

Hnh 1.15. Kin trc RAN thng nht ca 3GR3.1TS. Nguyn Phm Anh Dng

25

1.10. CU HNH A L CA H THNG THNG TIN DI NG 3GDo tnh cht di ng ca thu bao di ng nn mng di ng phi c t chc theo mt cu trc a l nht nh mng c th theo di c v tr ca thu bao.

1.10.1. Phn chia theo vng mngTrong mt quc gia c th c nhiu vng mng vin thng, vic gi vo mt vng mng no phi c thc hin thng qua tng i cng. Cc vng mng di ng 3G c i din bng tng i cng GMSC hoc GGSN. Tt c cc cuc gi n mt mng di ng t mt mng khc u c nh tuyn n GMSC hoc GGSN. Tng i ny lm vic nh mt tng i trung k vo cho mng 3G. y l ni thc hin chc nng hi nh tuyn cuc gi kt cui trm di ng. GMSC/GGSN cho php h thng nh tuyn cc cuc gi vo t mng ngoi n ni nhn cui cng: cc trm di ng b gi.

1.10.2. Phn chia theo vng phc v MSC/VLR v SGSNMt mng thng tin di ng c phn chia thnh nhiu vng nh hn, mi vng nh ny c phc v bi mt MSC/VLR (hnh 1.16a). hay SGSN (1.16b) Ta gi y l vng phc v ca MSC/VLR hay SGSN.

Hnh 1.16. Phn chia mng thnh cc vng phc v ca MSC/VLR v SGSN nh tuyn mt cuc gi n mt thu bao di ng, ng truyn qua mng s c ni n MSC ang phc v thu bao di ng cn gi. mi vng phc v MSC/VLR thng tin v thu bao c ghi li tm thi VLR. Thng tin ny bao gm hai loi: Thng tin v ng k v cc dch v ca thu bao. Thng tin v v tr ca thu bao (thu bao ang vng nh v hoc vng nh tuyn no).

1.10.3. Phn chia theo vng nh v v vng nh tuynMi vng phc v MSC/VLR c chia thnh mt s vng nh v: LA (Location Area) (hnh 1.17a). Mi vng phc v ca SGSN c chia thnh cc vng nh tuyn (RA: Routing Area) (1.17b).TS. Nguyn Phm Anh Dng

26

Hnh 1.17. Phn chia vng phc v ca MSC/VLR v SGSN thnh cc vng nh v (LA: Location Area) v nh tuyn (RA: Routing Area) Vng nh v (hay vng nh tuyn l mt phn ca vng phc v MSC/VLR (hay SGSN) m mt trm di ng c th chuyn ng t do v khng cn cp nht thng tin v v tr cho MSC/VLR (hay SGSN) qun l v tr ny. C th ni vng nh v (hay vng nh tuyn) l v tr c th nht ca trm di ng m mng cn bit nh tuyn cho mt cuc gi n n. vng nh v ny thng bo tm s c pht qung b tm thu bao di ng b gi. H thng c th nhn dng vng nh v bng cch s dng nhn dng vng nh v (LAI: Location Area Identity) hay nhn dng vng nh tuyn (RAI Routing Area Identity). Vng nh v (hay vng nh tuyn) c th bao gm mt s v thuc mt hay nhiu RNC, nhng ch thuc mt MSC (hay mt SGSN).

1.10.4. Phn chia theo Vng nh v hay vng nh tuyn c chia thnh mt s (hnh 1.18).

Hnh 1.18. Phn chia LA v RA l mt vng ph v tuyn c mng nhn dng bng nhn dng ton cu (CGI: Cell Global Identity). Trm di ng nhn dng bng m nhn dng trm gc (BSIC: Base Station Identity Code). Vng ph ca cc thng c m phng bng hnh lc gic tin cho vic tnh ton thit k.TS. Nguyn Phm Anh Dng

27

1.10.5. Mu Mu c hai kiu: v hng ngang (omnidirectional) v phn on (sectorized). Cc mu ny c cho trn hnh 1.19.

Hnh 1.19. Cc kiu mu v hng ngang (hnh 1.19a) nhn c t pht x ca mt anten c bp sng trn trong mt ngang (mt phng song song vi mt t) v bp sng c hng chc xung mt t trong mt ng (mt phng vung gc vi mt t). phn on (hnh 1.19b) l nhn c t pht x ca ba anten vi hng pht x cc i lch nhau 1200. Cc anten ny c bp sng dng na s 8 trong mt ngang v trong mt ng bp sng ca chng chc xung mt t. Trong mt s trng hp phn on c th c to ra t pht x ca nhiu hn ba anten. Trong thc t mu c th rt a dng ty vo a hnh cn ph sng. Tuy nhin cc mu nh trn hnh 1.19 thng c s dng thit k cho s ph sng chun.

1.10.6. Tng kt phn chia vng a l trong cc h thng thng tin di ng 3GTrong cc kin trc mng bao gm c min chuyn mch knh v min chuyn mch gi, vng phc mng khng ch c phn chia thnh cc vng nh v (LA) m cn c phn chia thnh cc vng nh tuyn (RA: Routing Area). Cc vng nh v (LA: Location Area) l khi nim qun l di ng ca min CS k tha t mng GSM. Cc vng nh tuyn (RA: Routing Area) l cc thc th ca min PS. Mng li PS s dng RA tm gi. Nhn dng thu bao P-TMSI (Packet- Temporary Mobile Subsscriber Identity: nhn dng thu bao di ng gi tm thi) l duy nht trong mt RA. Trong mng truy nhp v tuyn, RA li c chia tip thnh cc vng ng k UTRAN (URA: UTRAN Registration Area). Tm gi khi xng UTRAN s dng URA khi knh bo hiu u cui c thit lp. URA khng th nhn thy c bn ngoi UTRAN. Quan h gia cc vng c phn cp nh cho hnh 1.20 ( khng c th hin). LA thuc 3G MSC v RA thuc 3G SGSN. URA thuc RNC. Theo di v tr theo URA v trong UTRAN c thc hin khi c kt ni RRC (Radio ResourceTS. Nguyn Phm Anh Dng

28

Control: iu khin ti nguyn v tuyn) cho knh bo hiu u cui. Nu khng c kt ni RRC, 3G SGSN thc hin tm gi v cp nht thng tin v tr c thc hin theo RA.

Hnh 1.20. Cc khi nim phn chia vng a l trong 3G WCDMA UMTS.

1.11. TNG KTChng ny trc ht xt tng quan qu trnh pht trin thng tin di ng ln 4G. Nu cng ngh a truy nhp cho 3G l CDMA th cng ngh a truy nhp cho 4G l OFDMA. Sau kin trc mng 3G c xt. Mng li 3G bao gm hai vng chuyn mch: (1) vng chuyn mch cc dch v CS v (2) vng chuyn mch cc dch v PS. Cc pht hnh nh du cc mc quan trng pht trin mng 3G WCDMA UMTS c xt: R3, R4, R5 v R6. R3 bao gm hai min chuyn mch knh v chuyn mch gi trong kt ni gia cc nt chuyn mch gi l TDM (ghp knh theo thi gian). R4 l s pht trin ca R3 trong min chuyn mch knh chuyn thnh chuyn mch mm v kt ni gia cc nt mng bng IP. R5 v R6 h tr cc dch v a phng tin IP hon ton da trn chuyn mch gi. p ng c nhim v ny ngoi min chuyn mch gi, mng c b sung thm phn h a phng tin IP (IMS). Ct li ca IMS l CSCF thc hin khi u kt ni a phng tin IP da trn giao thc khi u phin (SIP Session Initiation Protocol). Ngoi ra IMS vn cn cha chuyn mch mm h tr dch v chuyn mch knh (MGCF). Hin nay mng 3GWCDMA UMTS ang giai don chuyn dn t R4 sang R5 (hnh 1.12). Cui chng trnh by cu trc a l ca mt mng thng tin di ng 3G c cha c vng chuyn mch knh v vng chuyn mch gi.

Chng 2 CNG NGH A TRUY NHP CA WCDMATS. Nguyn Phm Anh Dng

29

2.1. GII THIU CHUNG 2.1.1. Mc ch chng Hiu tng quan tri ph v phng php a truy nhp ca WCDMA Hiu iu khin cng sut, chuyn giao mm v my thu phn tp a ng (RAKE) Hiu cc dng m tri ph v cc s iu ch ca WCDMA

2.1.2. Cc ch c trnh by trong chng Nguyn l tri ph v a truy nhp phn chia theo m iu khin cng sut Chuyn giao My thu phn tp a ng (my thu RAKE) Cc dng m tri ph v cc s iu cht c s dng cho WCDMA

2.1.3. Hng dn Hc k cc t liu c trnh by trong chng Tham kho thm cc ti liu tham kho cui ti liu ging dy ca kha hc

2.2. TRI PH V A TRUY NHP PHN CHIA THEO M 2.2.1. Cc h thng thng tin tri phTrong cc h thng thng tin thng thng rng bng tn l vn quan tm chnh v cc h thng ny c thit k s dng cng t rng bng tn cng tt. Trong cc h thng iu ch bin song bin, rng bng tn cn thit pht mt ngun tn hiu tng t gp hai ln rng bng tn ca ngun ny. Trong cc h thng iu tn rng bng tn ny c th bng vi ln rng bng tn ngun ph thuc vo ch s iu ch. i vi mt tn hiu s, rng bng tn cn thit c cng gi tr vi tc bit ca ngun. rng bng tn chnh xc cn thit trong trng hp ny ph thuc v kiu iu ch (BPSK, QPSK v.v...). Trong cc h thng thng tin tri ph (vit tt l SS: Spread Spectrum) rng bng tn ca tn hiu c m rng, thng thng hng trm ln trc khi c pht. Khi ch c mt ngi s dng trong bng tn SS, s dng bng tn nh vy khng c hiu qu. Tuy nhin mi trng nhiu ngi s dng, cc ngi s dng ny c th dng chung mt bng tn SS (tri ph) v h thng tr nn s dng bng tn c hiu sut m vn duy tr c cc u im ca tri ph. Mt h thng thng tin s c coi l SS nu: * Tn hiu c pht chim rng bng tn ln hn rng bng tn ti thiu cn thit pht thng tin.TS. Nguyn Phm Anh Dng

30

* Tri ph c thc hin bng mt m c lp vi s liu. C ba kiu h thng SS c bn: chui trc tip (DSSS: Direct-Sequence Spreading Spectrum), nhy tn (FHSS: Frequency-Hopping Spreading Spectrum) v nhy thi gian (THSS: Time-Hopping Spreading Spectrum). Cng c th nhn c cc h thng lai ghp t cc h thng ni trn. WCDMA s dng DSSS. DSSS t c tri ph bng cch nhn lung s cn truyn vi mt m tri ph c tc chip (Rc=1/Tc, Tc l thi gian mt chip) cao hn nhiu tc bit (Rb=1/Tb, Tb l thi gian mt bit) ca lung s cn pht. Hnh 2.1 minh ha qu trnh tri ph trong Tb=15Tc hay Rc=15Rb. Hnh 2.1a cho thy s n gin ca b tri ph DSSS trong lung s cn truyn x c tc Rb c nhn vi mt m tri ph c tc Rc c lung u ra y c tc Rc ln hn nhiu so vi tc Rb ca lung vo. Cc hnh 2.1b v 2.1b biu th qu trnh tri ph trong min thi gian v min tn s. Ti pha thu lung y c thc hin gii tri ph khi phc li lung x bng cch nhn lung ny vi m tri ph c ging nh pha pht: x=y c

x, y v c k hiu tng qut cho tn hiu vo, ra v m tri ph; x(t), y(t) v c(t) k hiu cho cc tn hiu vo, ra v m tri ph trong min thi gian; X(f), Y(f) v C(f) k hiu cho cc tn hiu vo, ra v m tri ph trong min tn s; Tb l thi gian mt bit ca lung s cn pht, Rb=1/Tb l tc bit ca lung s cn truyn; Tc l thi gian mt chip ca m tri ph, Rc=1/Tc l tc chip ca m tri ph. Rc=15Rb v Tb=15Tc.

Hnh 2.1. Tri ph chui trc tip (DSSS)

2.2.2. p dng DSSS cho CDMA


31

Trong cng ngh a truy nhp phn chia theo m da trn CDMA, mt tp m trc giao c s dng v mi ngi s dng c gn mt m tri ph ring. Cc m tri ph ny phi m bo iu kin trc giao sau y: 1. Tch hai m ging nhau bng 1: ci ci=1 2. Tch hai m khc nhau s l mt m mi trong tp m: ci cj=ck1 N 3. C s bit 1 bng s bit -1 trong mt m Ck = 0 , trong N l s chip v N k=1

Ck l gi tr chip k trong mt m Bng 2.1. cho thy th d s dng b m gm tm m trc giao: c0, c1, , c7. Bng 2.2 v 2.3 cho thy th d khi nhn hai m ging nhau trong bng 1 c 1 v nhn hai m khc nhau trong bng 2.1 ta c mt m mi.. Bng 2.1. Th d b tm m trc giao c0 c1 c2 c3 c4 c5 c6 c7 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 -1 -1 -1 -1 +1 +1 -1 -1 +1 +1 -1 -1 +1 +1 -1 -1 -1 -1 +1 +1 +1 -1 +1 -1 +1 -1 +1 -1 +1 -1 +1 -1 -1 +1 -1 +1 +1 -1 -1 +1 +1 -1 -1 +1 +1 -1 -1 +1 -1 +1 +1 -1

Bng 2.2. Th d nhn hai m ging nhau trong bng 1 c mt c1 c1 c1 c1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 -1 -1 +1 -1 -1 +1 -1 -1 +1 -1 -1 +1

Bng 2.3. Th d nhn hai m khc nhau trong bng 1 c mt m mi trong tp 8 m c1 c3 = c2 +1 +1 +1 +1 +1 +1 +1 -1 -1 +1 -1 -1 -1 -1 +1 -1 -1 +1 -1 +1 -1 -1 +1 -1

Nu ta xt mt h thng gm K ngi s dng c xy dng trn c s CDMA, th sau tri ph cc ngi s dng ny s pht vo khng gian tp cc tn hiu y nh sau:TS. Nguyn Phm Anh Dng

32

y = yi = ci xii =1 i =1

K

K

(2.1)

Ta xt qu trnh x l tn hiu ny ti mt my thu k. Nhim v ca my thu ny l phi ly ra xk v loi b cc tn hiu khc (cc tn hiu ny c gi l nhiu ng knh v trong h thng CDMA chng c pht trn cng mt tn s vi xk). Nhn (2.1) vi xk v p dng quy tc trc giao ni trn ta c:% xk = xk + ci xii =1 i k K

(2.2)

Thnh phn th nht trong (2.2) chnh l tn hiu hu ch cn thnh phn th hai l nhiu ca cc ngi s dng cn l nhiu ca cc ngi s dng khc c gi l MAI (Multiple Access Interferrence: nhiu a ngi s dng). loi b thnh phn th hai my thu s dng b lc tng quan trng min thi gian kt hp vi b lc tn s trong min tn s. Hnh 2.2 xt qu trnh gii tri ph v lc ra tn hiu hu ch ti my thu k trong mt h thng CDMA c K ngi s dng vi gi thit cng sut pht t K my pht nh nhau ti u vo my thu k. Hnh 2.2a cho thy s gii tri ph DSSS. Hnh 2.2b cho thy ph ca tn hiu tng c pht i t K my pht sau tri ph, hnh 2.2c cho thy ph ca tn hiu ny sau gii tri ph ti my thu k v hnh 2.2d cho thy ph ca tn hiu sau b lc thng thp vi bng thng bng Rb.

Hnh 2.2. Qu trnh gii tri ph v lc tn hiu ca ngi s dng k t K tn hiu. T hnh 2.2 ta thy t s tn hiu trn nhiu (SIR: Signal to Interference Ratio) l t s gia din tch hnh ch nht c t m trn hnh 2.2.b v tng din tch cc hnh ch nht trng trn hnh 2.2.c: SIR=S1/S2. T s ny t l vi t s Rc/Rb. v th t s Rc/Rb c gi l li x l (TA: Processing Gain).TS. Nguyn Phm Anh Dng

33

2.3. IU KHIN CNG SUTTrong trng hp mt my pht gy nhiu n gn my thu k (n gn nt B chng hn), cng sut ca my pht ny tng cao dn n MAI tng cao, t s tn hiu trn nhiu gim mnh v my thu k khng th tch ra c tn hiu ca mnh. Hin tng ny c gi l hin tng gn v xa. trnh hin tng ny h thng phi iu khin cng sut sao cho cng sut thu ti nt B ca tt c cc UE u bng nhau (l tng). iu khin cng sut trong WCDMA c chia thnh: iu khin cng sut vng h iu khin cng sut vng kn iu khin cng sut vng h c thc hin t ng ti UE khi n thc hin th tc xin truy nhp Nt B (da trn cng sut m n thu c t knh hoa tiu pht i t B), khi ny UE cha c kt ni vi nt ny. Cn iu khin cng sut vng kn c thc hin khi UE kt ni vi nt B. iu khin cng sut vng h li c chia thnh: iu khin cng sut vng trong c thc hin ti nt B. iu khin cng sut vng trong c thc hin nhanh vi 1500 ln trong mt giy da trn so snh SIR thu vi SIR ch iu khin cng sut vng ngoi c thc hin ti RNC thit lp SIR ch cho nt B. iu khin cng sut ny da trn so snh t l li khi (BLER) thu c vi t l ch.

2.4. CHUYN GIAO TRONG H THNG CDMAThng thng chuyn giao (HO: Handover) c hiu l qu trnh trong knh lu lng ca mt UE c chuyn sang mt knh khc m bo cht lng truyn dn. Tuy nhin trong CDMA khi nim ny ch thch hp cho chuyn giao cng cn i vi chuyn giao mm khi nim ny phc tp hn, ta s xt c th trong phn di y. C th chia HO thnh cc kiu HO sau:

HO ni h thng xy ra bn trong mt h thng WCDMA. C th chia nh HO

ny thnh o HO ni h thng gia cc thuc cng mt tn s sng mang WCDMA o HO gia cc tn s (IF-HO) gia cc hot ng trn cc tn s WCDMA khc nhau HO gia cc h thng (IS-HO) gia cc thuc hai cng ngh truy nhp v tuyn (RAT) khc nhau hay cc ch truy nhp v tuyn (RAM) khc nhau. Trng hp thng xuyn xy ra nht i vi kiu th nht l HO gia cc h thng WCDMA v GSM/EDGE. Tuy nhin cng c th l IS-HO gia WCDMA v h thng cc h thng CDMA khc (cdma2000 1x chng hn). Th d v HO gia cc RAM l HO gia cc ch UTRA FDD v UTRA TDD. 34


C th c cc th tc HO sau:

Chuyn giao cng (HHO) l cc th tc HO trong tt c cc ng truyn v

tuyn c ca mt UE c gii phng trc khi thit lp cc ng truyn v tuyn mi Chuyn giao mm (SHO) v chuyn giao mm hn (xem hnh 2.3) l cc th tc trong UE lun duy tr t nht mt ng v tuyn ni n UTRAN. Trong chuyn giao mm UE ng thi c ni n mt hay nhiu thuc cc nt B khc nhau ca cng mt RNC (SHO ni RNC) hay thuc cc RNC khc nhau (SHO gia cc RNC). Trong chuyn giao mm hn UE c ni n t nht l hai on ca cng mt nt B. SHO v HO mm hn ch c th xy ra trn cng mt tn s sng mang v trong cng mt h thng.

Hnh 2.3. Chuyn giao mm (a) v mm hn (b) Ph thuc s tham gia trong SHO, cc trong mt h thng WCDMA c chia thnh cc tp sau y: Tp tch cc bao gm cc (on ) hin ang tham gia vo mt kt ni SHO ca UE Tp ln cn/ tp c gim st (c hai t c s dng nh nhau). Tp ny bao gm tt c cc c gim st/o lin tc bi UE v hin thi khng c trong tp tch cc Tp c pht hin. Tp ny bao gm cc c UE pht hin nhng khng thuc tp tch cc ln tp ln cn. SHO l mt tnh nng chung ca h thng WCDMA trong cc ln cn hat ng trn cng mt tn s. Trong ch kt ni, UE lin tc o cc phc v v cc ln cn (do RNC ch dn) trn tn s sng mang hin thi. UE so snh cc kt qu o vi cc ngng HO do RNC cung cp v gi bo co kt qu o n RNC khi thc hin cc tiu chun bo co. V th SHO l kiu chuyn giao c nh gi bi u cui di ng (MEHO: Mobile Estimated HO). Tuy nhin gii thut quyt nh SHO c t trong RNC. Da trn cc bo co kt qu o nhn c t UE (hoc nh kTS. Nguyn Phm Anh Dng

35

hoc c khi ng bi mt s cc s kin nht nh), RNC lnh cho UE b sung hay loi b mt s khi tp tch cc ca mnh (ASU: Active Set Apdate: cp nht tp tch cc).

2.5. MY THU PHN TP A NG HAY MY THU RAKEPhainh a ng trn knh v tuyn dn n tn thi v chn lc tn s lm hng tn hiu thu. nh gi hin tng tn thi trn ng truyn v tuyn, ngi ta pht i mt xung hp (xung kim) v o p ng xung ny ti pha thu. p ng ny l bc tranh th hin s ph thuc cng sut ca cc ng truyn khc nhau n my thu vo thi gian tr ca cc ng truyn ny. p ng ny c gi l l lch tr cng sut. Hnh 2.4a cho thy truyn sng a ng v hnh 2.4b cho thy th d v l lch tr cng sut.

Hnh 2.4. Truyn sng a ng v l lch tr cng sut Chui tn hiu gi ngu nhin c pht i CDMA c thuc tnh l cc phin bn dch thi ca n ti pha thu hu nh khng tng quan. Nh vy mt tn hiu c truyn t my pht n my thu theo nhiu ng khc nhau (thi gian tr khc nhau) c th c phn gii vo cc tn hiu phainh khc nhau bng cch ly tng quan tn hiu thu cha nhiu phin bn dch thi ca chui gi ngu nhin. My thu s dng nguyn l ny c gi l my thu phn tp a ng hay my thu RAKE (hnh 2.5).


36

Hnh 2.5. My thu RAKE Trong my thu RAKE nhn c cc phin bn dch thi ca chui ngu nhin, tn hiu thu phi i qua ng tr trc khi c ly tng quan v c kt hp. ng tr bao gm nhiu mt tr c thi gian tr bng thi gian mt chip T c. My thu dch nh thi bn sao m tri ph tng chip cho tng k hiu thng tin gii tri ph k hiu trong vng mt k hiu v to nn l lch tr cng sut (xem hnh 2.5a). Vi tham kho l lch tr cng sut (bc tranh th hin cng sut v tr ca cc ng truyn) c to ra, my thu chn cc ng truyn c cng sut vt ngng kt hp RAKE trn c s s lng b tng quan, b c tnh knh v b b tr thay i pha (c gi l cc ngn my thu RAKE). Trong trng hp p dng thu phn tp khng gian hay phn tp gia cc on , l lch tr cng sut c to ra cho mi nhnh v cc ng truyn c chn t l lch tr cng sut sut tng hp ca tt c cc nhnh. Trong thc t, v cc tn hiu tri ph gm nhiu ca cc ngi s dng khc v cc tn hiu a ng ca knh ngi s dng, nn gi tr ngng c lp d trn mc cng sut tp m nn v cc ng truyn c SIR hiu dng (c cng sut thu vt ngng) c chn. V MS chuyn ng (hoc mi trng truyn sng thay i khi MS c nh), nn v tr ng truyn (thi gian tr) c kt hp RAKE cng s thng xuyn thay i, my phi nh k cp nht l lch tr ng truyn v cp nht cc ng truyn c kt hp RAKE trn c s l lch mi (qu trnh ny c gi l tm kim ng truyn v n lin quan n tm kim ng truyn kt hp RAKE).

2.6. CC M TRI PH S DNG TRONG WCDMAKhi nim tri ph c p dng cho cc knh vt l, khi nim ny bao gm hai thao tc. u tin l thao tc nh knh, trong mi k hiu s liu dc chuyn thnh mt s chip nh vy tng rng ph tn hiu. S chip trn mt k hiu (hay tTS. Nguyn Phm Anh Dng

37

s gia tc chip v tc k hiu) c gi l h s tri ph (SF: Spectrum Factor), hay ni mt cch khc SF=Rs/Rc trong Rs l tc k hiu cn Rc l tc chip. H s tri ph l mt gi tr kh bin, ngoi tr i vi knh chia s ng xung vt l tc cao (HS-PDSCH ) trong HSDPA c SF=16. Thao tc th hai l thao tc ngu nhin ha tng tnh trc giao trong mt m ngu nhin ha c trn vi tn hiu tri ph. M ngu nhin ho c xy dng trn c s m Gold. Trong qu trnh nh knh, cc k hiu s liu c nhn vi mt m OVSF (Orthogonal Variable Spread Factor: m trc giao h s kh bin) ng b v thi gian vi bin ca k hiu. Trong 3GPP, OVSF (hnh 2.6) c s dng cho cc tc k hiu khc nhau v c k hiu l Cch,SF,k trong SF l h s tri ph ca m v k l s th t m (0 k SF-1). Cc m nh knh c cc tnh cht trc giao v c s dng phn bit cc thng tin c pht i cng t mt ngun: (1) cc kt ni khc nhau trn ng xung trong cng mt trn ng xung v gim nhiu ni , (2) cc knh s liu vt l ng ln t mt UE. Trn ng xung cc m OVSF trong m b hn ch v th cn c qun l bi RNC, tuy nhin iu ny khng xy ra i vi ng ln. Cn lu khi chn m nh knh chng khng tng quan vi nhau. Chng hn khi chn m Cch,8,4=+1-1+1-1+1-1+1-1, khng c s dng m Cch,16,8=+1-1+1-1+11+1-1+1-1+1-1+1-1+1-1; v hai m ny hon ton ging nhau (tch ca chng bng 1) v chng s gy nhiu cho nhau. Cc m OVSF ch hiu qu khi cc knh c ng b hon ho ti mc k hiu. Mt tng quan cho do truyn sng a ng c b tr bi thao tc ngu nhin ha b sung. Vi thao tc ngu nhin ha, phn thc (I) v phn o (Q) ca tn hiu tri ph c nhn b sung vi m ngu nhin ha phc. M ngu nhin ha phc c s dng phn bit cc ngun pht: (1) cc khc nhau i vi ng xung v (2) cc UE khc nhau i vi ng ln. Cc m ny c cc tnh cht tng quan tt (trung bnh ha nhiu) v lun c s dng trn vi cc m tri ph nhng khng lm nh hng rng ph tn hiu v bng thng truyn dn.

Hnh 2.6. Cy m nh knh ng truyn gia nt B v UE trong WCDMA cha nhiu knh. C th chia cc knh ny thnh hai loi: (1) knh ring truyn lu lng v (2) knh chung mang cc thng tin iu khin v bo hiu. ng truyn t UE n nt B c gi lTS. Nguyn Phm Anh Dng

38

ng ln, cn ng ngc li t nt B n UE c gi l ng xung. Trc ht ta xt tri ph cho cc knh ng ln.

2.7. TRI PH V IU CH NG LN 2.7.1. Tri ph v iu ch cc knh ring ng lnNguyn l tri ph cho DPDCH (Dedicated Physical Data Channel: knh s liu vt l ring, knh truyn lu lng ca ngi s dng) v DPCCH (Dedicated Physical Control Channel: knh iu khin vt l ring; knh i cng vi DPDCH mang thng tin iu khin lp vt l) c minh ha trn hnh 2.7. Mt DPCCH v cc i su DPDCH song song gi tr thc c th c tri ph v pht ng thi. DPCCH lun c tri ph bng m Cc=Cch,256,0, trong k=0. Nu ch mt knh DPDCH c pht trn ng ln, th DPDCH1 c tri ph vi m Cd,1=Cch,SF,k, trong k=SF/4 l s m OVSF v k=SF/4. Ngha l nu h s tri ph SF=128 th k=32. Nu nhiu DPDCH c pht, th tt c DPDCH u c h s tri ph l 4 (tc bit knh l 960kbps) v DPDCHn c tri ph bi m Cd,n=Cch,4,k, trong k=1 nu n{1,2}, k=3 nu n{3,4} v k=2 nu n{5,6}. b tr s khc nhau gia cc h s tri ph ca s liu, tn hiu tri ph c nh trng s bng cc h s khuych i k hiu l c cho DPCCH v d cho DPDCH. Cc h s khuych i ny c tnh ton bi SRNC v c gi n UE trong giai on thit lp ng truyn v tuyn hay t li cu hnh. Cc h s khuych i nm trong di t 0 n 1 v t nht mt trong s cc gi tr ca c v d lun lun bng 1. Lung chip ca cc nhnh I v Q sau c cng phc vi nhau v c ngu nhin ha bi mt m ngu nhin ha phc c k hiu l Sdpch,n trn hnh 2.7. M ngu nhin ha ny c ng b vi khung v tuyn, ngha l chip th nht tng ng vi u khung v tuyn.

Hnh 2.7. Tri ph v iu ch DPDCH v DPCCH ng lnTS. Nguyn Phm Anh Dng

39

Cc nghin cu cho thy mi s pht khng lin tc trn ng ln c th gy nhiu m thanh cho thit b m thanh t gn my u cui di ng. Th d in hnh l trng hp nhiu tn s khung (217 Hz=1/4,615ms) gy ra do cc u cui GSM. trnh hiu ng ny, knh DPCCH v cc knh DPDCH khng c ghp theo thi gian m c ghp theo m I/Q (iu ch QPSK hai knh) vi ngu nhin ho phc. Minh ha trn hnh 2.8 cho thy s iu ch ny cho php truyn dn lin tc ngay c trong cc chu k im lng khi ch c thng tin iu khin lp 1 duy tr hot ng ng truyn (DPCCH) l c pht.

Hnh 2.8. Truyn dn knh iu khin vt l ring ng ln v knh s liu vt l ring ng ln khi c/ khng c (DTX) s liu ca ngi s dng Nh minh ha trn hnh 2.9, cc m ngu nhin ha phc c to ra bng cch quay pha gia cc chip trong mt chu k k hiu trong gii hn 900. Bng cch ny hiu sut ca b khuch i (lin quan n t s cng sut nh trn cng sut trung bnh) trong UE hu nh khng i khng ph th thuc vo t s gia DPDCH v DPCCH.

Hnh 2.9. Chm tn hiu i vi ghp m I/Q s dung ngu nhin ha phc, biu din cho t s cng sut gia DPDCH v DPCCH. DPCCH v cc DPDCH c th c ngu nhin ha bng cc m ngu nhin di hoc ngn. C 224 m ngu nhin ha di ng ln v 224 m ngu nhin ngn ng ln. V c th s dng c hng triu m nn khng cn quy hoch m ng ln. S m ngu nhin cho DPCH (0,., 16777215), cng vi SF thp nht c php ca m nh knh (4, 8, 16, 32, 128 v 256) cho phn s liu c n nh bi cc lp cao hn, chng hn khi thit lp kt ni RRC hoc khi iu khin chuyn giao.TS. Nguyn Phm Anh Dng

40

2.7.2. Tri ph v iu ch knh chung ng ln PRACHPhn ny s trnh by n nh m cho tin t v phn bn tin ca PRACH l mt dng knh chung ng ln. Tri ph v ngu nhin ha phn bn tin PRACH c minh ha trn hnh 2.10.

Hnh 2.10. Tri ph v iu ch phn bn tin PRACH Phn iu khin ca bn tin PRACH c tri ph bng m nh knh Cc=Cch,256,m, trong m=16.s+15 v s (0 s 15) l ch k tin t v phn s liu c tri ph bng m nh knh Cd=Cch,SF,m, trong SF (c gi tr t 32 n 256) l h s tri ph s dng cho phn s liu v m=SF.s/16. Phn bn tin PRACH lun lun c tri ph bng m ngu nhin ha di. di ca m ngu nhin ha c s dng cho phn bn tin l 10ms. C tt c l 8192 m ngu nhin ha.

2.8. TRI PH V IU CH NG XUNG 2.8.1. S tri ph v iu ch ng xungKhi nim tri ph v ngu nhin ha ng xung c minh ha trn hnh 2.11. Ngoi tr cc SCH (knh ng b s xt trong chng 3), mi cp hai bit knh trc ht c bin i t ni tip vo song song tng ng mt k hiu iu ch, sau c t ln cc nhnh I v Q. Sau cc nhnh I v Q c tri ph n tc 3,84Mcps bng cng mi m dnh knh Cch,SF,m. Cc chui chip gi tr thc trn cc nhnh I v Q sau c ngu nhin ha bng m ngu nhin ha phc nhn dng ngun pht nt B, m ny c k hiu l Sdl,n trn hnh 2.11. M ngu nhin ha ny c ng b vi m ngu nhin ha s dng cho P-CCPCH (knh vt l iu khin chung s cp s xt trong cng 3), trong chp phc u tin ca khung P-CCPCH c nhn vi chip s 0 ca m ngu nhin ha ny. Sau tri ph, mi knh vt l ng xung (tr cc SCH) c nh trng s bng cc h s trng s ring k hiu l Gi nh trn hnh 2.11. P-SCH v S-SCH gi tr phc c nh trng s ring bng cc h s trng s Gp v Gs. Tt c cc knh ng xung c kt hp vi nhau bng cng phc. Chui nhn c sau tri ph v ngu nhin ha c iu ch QPSK.TS. Nguyn Phm Anh Dng

41

Hnh 2.11. S tri ph v iu ch cho tt c cc knh vt l ng xung

2.8.2. Cc m tri ph ng xungTrn ng xung, cng cc m nh knh nh trn ng ln (m OVSF) c s dng. Thng thng mi ch c mt cy m v mi cy m c t di mt m ngu nhin ha dng chung cho nhiu ngi s dng. Theo quy inh, cc m nh knh dng cho P-CPICH (knh hoa tiu chung s cp s xt trong chng 3) v P-CCPCH l Cch,256,0 v Cch,256,1. B qun l ti nguyn trong RNC n nh cc m nh knh cho tt c cc knh khc vi gii hn SF=512 trong trng hp s dng chuyn giao phn tp. M OVSF c th thay i theo tng khung trn knh PDSCH (knh chia s ng xung vt l s xt trong chng 3). Quy tc thay i nh sau, m (cc m) OVSF c s dng cho kt ni pha di h s tri ph nh nht l m t nhnh cy, m nhnh cy m c ch ra bi h s tri ph thp nht ny. Nu DSCH c sp xp ln nhiu PDSCH song song, th quy tc tng t c p dng, nhng tt cc nhnh m c s dng bi cc m ny tng ng vi h s tri ph nh nht u c th s dng cho n nh h s tri ph cao hn.

2.8.3. Cc m ngu nhin ha ng xungTrn ng xung ch c cc m ngu nhin ha di l c s dng. C c thy 2 -1=262143 m ngu nhin c nh s t 0 n 262142. Cc chui m ngu nhin c k hiu l Sdl,n c cu trc bng cc on ca chui Gold. tng tc qu trnh tm , ch 8192 m trong s 262143 c s dng trong thc t v c ct ngn ly on u 38400 chip ph hp vi chu k khung 10 ms. Nh minh ha trn hnh 2.12, ch c cc m vi n=0,1,, 8191 c s dng. Cc m ny c chia thnh 512 tp. Mi tp gm 16 m (i=015) vi mt m s cp v 15 m th cp. 8 tp (i=07) vi 8x16 m hp thnh mt nhm to nn 64 nhm (j=063).18


42

Hnh 2.12. Cc m ngu nhin ha s cp v th cp V thng thng mi c nhn dng bng mt m ngu nhin ho s cp, nn qu trnh tm kim cng l qu trnh tm kim m ny. Qu trnh tm kim c th c thc hin theo ba bc sau: Tm P-SCH (knh ng b s cp) thit lp ng b khe v ng b k hiu Tm S-SCH (knh ng b th cp) thit lp ng b khung v nhm m Tm m ngu nhin ha nhn dng

2.8.4. Ghp knh a m ng xung tng dung lng knh ng xung ta c th s dng s ghp knh a m nh cho hnh 2.13.

S/P: bin i ni tip thnh song song

Hnh 2.13. Truyn dn a m cho ng xungTS. Nguyn Phm Anh Dng

43

2.9. TNG KTCc h thng CDMA c xy dng trn c s tri ph chui trc tip (DSSS). Vic s dng tri ph cng vi cc m trc giao cho php nhiu u cui di ng c th dng chung mt tn s. Khi ny tnh trc giao ca cc m v tri ph cho php mt my thu u cui c th d dng tch ra c tn hiu ca mnh. Do s dng chung mt tn s nn c th p dng chuyn giao mm cho CDMA. Trong chuyn giao mm mt my di ng c th kt ni n nhiu trm gc trn cng mt tn s nhng vi m tri ph khc nhau. u im ca chuyn giao mm l khng lm mt cuc gi trong qu trnh chuyn giao mc d n lm gim phn no dng lng v tng thm tnh phc tp h thng. Nhng cng v s dng chung mt tn s nn c th xy ra hin tng gn xa, trong my di ng gn trm gc s gy nhiu cho cc ngi s dng khc. khc phc nhc im ny phi p dng iu khin cng sut nhanh cho CDMA trong my di ng gn trm gc s c iu chnh pht cng sut thp hn my di ng xa trm gc. iu khin cng sut nhanh trong WCDMA c thc hin 1500 ln trong mt giy. Mt c im na ca CDMA l cc m ngu nhin ha mang tnh trc giao kh cao nn cc ng truyn n my thu c tr khc nhau thi gian chip hoc ln hn thi gian ny u c lp vi nhau v v th c th s dng phn tp a ng (hay my thu RAKE) trong CDMA. Nguyn tc ca my thu RAKE l chn mt s ng (mt s ngn) c cng sut thu ln hn ngng, ng chnh pha cc ng ny ri cng cng sut thu ca chng vi nhau. WCDMA s dng hai tng tri ph: (1) tri ph bng m nh knh, (2) tri ph bng m nhn dng ngun pht. M nh knh c xy dng trn c s m h s tri ph trc giao kh bin (OVSF), trong h s tri ph SF=R s/Rc vi Rs l tc k hiu v Rc l tc chip. M ngu nhin ha c cu trc t m Gold. WCDMA s dng iu ch QPSK cho ng xung v BPSK cho ng ln. gim t s cng sut nh trn cng sut trung bnh ca tn hiu iu ch, ngu nhin ha phc c s dng.


44

Chng 3 GIAO DIN V TUYN CA WCDMA UMTS3.1. GII THIU CHUNG 3.1.1. Mc ch chng Hiu tng quan v WCDMA/FDD Hiu kin trc WCDMA v cc knh ca n Hiu c cc k thut phn tp pht trong WCDMA

3.1.2. Cc ch c trnh by trong chng Kin trc giao din v tuyn ca 3G WCDMA/FDD Cc thng s lp vt l v quy hoch tn s ca WCDMA/FDD Cc kiu knh ca WCDMA/FDD S tng qut ca mt thit b thu pht WCDMA Cc s phn tp pht c s dng cho WCDMA Cc s iu ch v chuyn giao trong WCDMA Cc thng s quan trng my thu v my pht v tuyn ca UE M ha ting AMR

3.1.3. Hng dn Hc k cc t liu c trnh by trong chng Tham kho thm cc ti liu tham kho cui ti liu ging dy ca kha hc

3.2. M UWCDMA UMTS l mt trong cc tiu chun ca IMT-2000 nhm pht trin ca GSM cung cp cc kh nng cho th h ba. WCDMA UMTS s dng mng a truy nhp v tuyn trn c s W-CDMA v mng li c pht trin t GSM/GPRS. W-CDMA c th c hai gii php cho giao din v tuyn: ghp song cng phn chia theo tn s (FDD: Frequency Division Duplex) v ghp song cng phn chia theo thi gian (TDD: Time Division Duplex). C hai giao din ny u s dng tri ph chui trc tip (DS-CDMA). Gii php th nht s c trin khai rng ri cn gii php th hai ch yu s c trin khai cho cc nh (Micro v Pico). Hin nay mi ch c WCDMA/FDD c trin khai v th trong kha hc ny ta s ch xt WCDMA/FDD Gii php FDD s dng hai bng tn 5 MHz vi hai sng mang phn cch nhau 190 MHz: ng ln c bng tn nm trong di ph t 1920 MHz n 1980 MHz, ng xung c bng tn nm trong di ph t 2110 MHz n 2170 Mhz. Mc d 5 MHz l rng bng danh nh, ta cng c th chn rng bng t 4,4 MHz n 5TS. Nguyn Phm Anh Dng

45

MHz vi nc tng l 200 KHz. Vic chn rng bng ng n cho php ta trnh c nhiu giao thoa nht l khi khi 5 MHz tip theo thuc nh khai thc khc. Gii php TDD s dng cc tn s nm trong di 1900 n 1920 MHz v t 2010 MHz n 2025 MHz; y ng ln v ng xung s dng chung mt bng tn. Giao din v tuyn ca W-CDMA/FDD ( n gin ta s b qua k hiu FDD nu khng xt n TDD) hon ton khc vi GSM v GPRS, W-CDMA s dung phng thc tri ph chui trc tip vi tc chip l 3,84 Mcps. Trong WCDMA mng truy nhp v tuyn c gi l UTRAN (UMTS Terrestrial Radio Access Network). Cc phn t ca UTRAN rt khc vi cc phn t mng truy nhp v tuyn ca GSM. V th kh nng s dng li cc BTS v BSC ca GSM l rt hn ch. Mt s nh sn xut cng c k hoch nng cp cc GSM BTS cho WCDMA. i vi cc nh sn sut ny c th ch tho ra mt s b thu pht GSM t BTS v thay vo cc b thu pht mi cho WCDMA. Mt s rt t nh sn sut cn lp k hoch xa hn. H ch to cc BSC ng thi cho c GSM v WCDMA. Tuy nhin a phn cc nh sn sut phi thay th GSM BSC bng RNC mi cho WCDMA. W-CDMA s dng rt nhiu kin trc ca mng GSM, GPRS hin c cho mng ca mnh. Cc phn t nh MSC, HLR, SGSN, GGSN c th c nng cp t mng hin c h tr ng thi WCDMA v GSM. Giao din v tuyn ca WCDMA/FDD c xy dng trn ba kiu knh: knh logic, knh truyn ti v knh vt l. Knh logic c hnh thnh trn c s ng gi cc thng tin t lp cao trc khi sp xp vo knh truyn ti. Nhiu knh truyn ti c ghp chng vo knh vt l. Knh vt l c xy dng trn cng ngh a truy nhp CDMA kt hp vi FDMA/FDD. Mi knh vt l c c trng bi mt cp tn s v mt m tri ph. Ngoi ra knh vt l ng ln cn c c trng bi gc pha. Trong phn di y ta trc ht ta xt kin trc giao thc ca giao din v tuyn sau ta s xt giao din v tuyn ca WCDMA/FDD, sau s xt cc knh ny.

3.3. KIN TRC NGN XP GIAO THC CA GIAO DIN V TUYN WCDMA/FDDKin trc giao din v tuyn ca WCDMA c cho trn hnh 3.1.


46

UP: Mt phng ngi s dng CP: Mt phng iu khin

Hnh 3.1. Kin trc giao thc v tuyn cho UTRA FDD. Ngn xp giao thc ca giao din v tuyn bao gm 3 lp giao thc: Lp vt l (L1). c t cc vn lin quan n giao din v tuyn nh iu ch v m ha, tri ph v.v.. Lp lin kt ni s liu (L2). Lp khun s liu vo cc khi s liu v m bo truyn dn tin cy gia cc nt ln cn hay cc thc th ng cp Lp mng (L3). c t nh a ch v nh tuyn Mi khi th hin mt trng hp ca giao thc tng ng. ng khng lin nt th hin cc giao din iu khin, qua giao thc RRC iu khin v lp cu hnh cc lp di. Lp 2 c chia thnh cc lp con: MAC (Medium Access Control: iu khin truy nhp mi trng) v RLC (Radio link Control: iu khin lin kt), PDCP (Packet Data Convergence Protocol: Giao thc hi t s liu gi) v BMC (Broadcast/Multicast Control: iu khin qung b/a phng ). Lp 3 v RLC c chia thnh hai mt phng: mt phng iu khin (C-Plane) v mt phng ngi s dng (U-Plane). PDCP v BMC ch c mt phng U. Trong mt phng C lp 3 bao gm RRC (Radio Resource Control: iu khin ti nguyn v tuyn) kt cui ti RAN v cc lp con cao hn: MM (Mobility Management) v CC (Connection Management), GMM (GPRS Mobility Management), SM (Session Management) kt cui ti mng li (CN). Lp vt l l lp thp nht giao din v tuyn. Lp vt l c s dng truyn dn giao din v tuyn. Mi knh vt l lp ny c xc nh bng mt t hp tn s, m ngu nhin ho (m nh knh) v pha (ch cho ng ln). Cc knh c s dng vt l truyn thng tin ca cc lp cao trn giao din v tuyn, tuy nhin cng c mt s knh vt l ch c dnh cho hot ng ca lp vt l.TS. Nguyn Phm Anh Dng

47

truyn thng tin giao din v tuyn, cc lp cao phi chuyn cc thng tin ny qua lp MAC n lp vt l bng cch s dng cc knh logic. MAC sp xp cc knh ny ln cc knh truyn ti trc khi a n lp vt l lp ny sp xp chng ln cc knh vt l.

3.4. CC THNG S LP VT L V QUY HOCH TN S 3.4.1. Cc thng s lp vt lCc thng s lp vt l ca WCDMA c cho trong bng 3.1. Bng 3.1. Cc thng s lp vt l W-CDMA W-CDMA S a truy nhp rng bng tn (MHz) Mnh ph Tc chip (Mcps) di khung ng b gia cc nt B M ha sa li iu ch DL/UL Tri ph DL/UL B m ha thoi T chc tiu chun DS-CDMA bng rng 5/10/15/20 200 kHz (1,28)/3,84/7,68/11,52/15,36 10 ms D b/ng b M turbo, m xon QPSK/BPSK QPSK/OCQPSK (HPSK) CS-ACELP/(AMR) 3GPP/ETSI/ARIB

DL: Downlink: ng xung; UL: Uplink: ng ln OCQPSK (HPSK): Orthogonal Complex Quadrature Phase Shift Keying (Hybrid PSK) = kha chuyn pha vung gc trc giao CS-ACELP: Conjugate Structure-Algebraic Code Excited Linear Prediction = D bo tuyn tnh kch thch theo m li s cu trc phc hp 3GPP: Third Generation Parnership Project: n ca cc i tc th h ba ETSI: European Telecommunications Standards Institute: Vin tiu chun vin thng Chu u ARIB: Association of Radio Industries and Business: Lin hip cng nghip v kinh doanh v tuyn

3.4.2. Quy hoch tn sCc bng tn s dng cho WCDMA FDD trn ton cu c cho trn hnh 3.2a. WCDMA s dng phn b tn s quy nh cho IMT-2000 (International Mobile Telecommunications-2000) (hnh 3.2b) nh sau. chu u v hu ht cc nc chu bng tn IMT-2000 l 2 60 MHz (1920-1980 MHz cng vi 2110-2170 MHz) c th s dng cho WCDMA/ FDD. Bng tn s dng cho TDD chu u thay i, bng tn c cp theo giy php c th l 25 MHz cho s dng TDD 19001920 (TDD1) v 2020-2025 MHz (TDD2). Bng tn cho cc ng dng TDD khng cn xin php (SPA= Self Provided Application: ng dng t cp) c th l 2010-2020TS. Nguyn Phm Anh Dng

48

MHz. Cc h thng FDD s dng cc bng tn khc nhau cho ng ln v ng xung vi phn cch l khong cch song cng, cn cc h thng TDD s dng cng tn s cho c ng ln v ng xung. UMTS quy nh khai thc song cng phn chia theo tn s l ch tiu chun cho thng tin thoi v s liu. Hot ng ng thi v lin tc ca cc mch in pht v thu l cc thay i ng k nht so vi hat ng ca GSM.

Hnh 3.2. Phn b tn s cho WCDMA/FDD. a) Cc bng c th dng cho WCDMA FDD ton cu; b) Bng tn IMT-2000. Bng tn cho hat ng FDD cho cc bng I, II v III c cho trn hnh 3.3. Bng I (B1) l n nh bng chnh Chu u. Quy nh dnh hai cp pht 60MHz vi khong cch song cng chun 190MHz, tuy nhin quy nh cng cho php song cng kh bin, trong khong cch pht thu nm trong khong 130 n 250MHz. H thng song cng kh bin t ra cc yu cu b sung i vi thit k my pht thu v cc b t tn s my pht v my thu phi hot ng c lp vi nhau. Bng II (B2) ti s dng bng hin c ca h thng thng tin di ng c nhn v d nh s dng M m bo ng tn ti UMTS v GSM. Khong cch song cng ch bng 80MHz i vi bng II v th t ra cc yu cu kh khn hn i vi phn cng ca my thu pht.


49

Hnh 3.3 Cp pht bng tn WCDMA/FDD Hnh 3.4 cho thy cp pht bng thng theo u thu ti Vng Quc Anh. Ph tn c chia cho nm nh khai thc nh sau: Cp php A (Hutchison) nhn cp pht bng kp 14,6 MHz (tng ng 3 5MHz vi bng bo v nh hn) Cp php B Vodafon) nhn cp pht bng kp 14,8MHz (tng ng 3 5MHz vi bng bo v nh hn) Cp php C (BT3G) nhn cp pht bng kp 10MHz (2 5MHz) v bng n 5MHz ti 1910 MHz Cp php D (One2One) nhn cp pht bng kp 10MHz (2 5MHz) v bng dn 5MHz ti 1900MHz Cp php E (Orange) nhn cp pht bng kp (2 5MHz) v bng n 5MHz ti 1905MHz.

Hnh 3.4. Th d cp pht bng tn cho nm nh khai thc ti Vng Quc Anh Cp pht tn s ca c khc vi cp pht tn s Anh ch, cc 10MHz bng kp c cp pht cho su nh khai thc (6 10MHz), tt c bn knh TDD1 c cp pht (1900 n 1920 MHz) cng vi mt trong s cc knh TDD2 (hnh 3.5).TS. Nguyn Phm Anh Dng

50

Hnh 3.5. Cp pht tn s cho su nh khai thc ti c Ti Vit Nam bng tn 3G c cp pht tn s theo tm khe tn s nh cho trong bng 3.2, trong hai hoc nhiu nh khai thc c th cng tham gia xin cp pht chung mt khe. Bng 3.2. Cp pht tn s 3G ti Vit Nam Khe tn s FDD BSTx* BSRx** A 2110-2125 MHz 1920-1935 MHz B 2125-2140 MHz 1935-1950 MHz C 2140-2155 MHz 1950-1965 MHz D 2155-2170 MHz 1965-1980 MHz * BSTx: my pht trm gc ** BSRx: my thu trm gc TDD BSTx/BSRx 1915-1920 MHz 1910-1915 MHz 1905-1910 MHz 1900-1905 MHz

L do cp pht cc knh 5MHz khc nhau ti cc nc khc nhau l ch cc nh khai thc phi quy hoch m v phi trnh vic s dng cc m gy ra nhiu knh ln cn trong cng mt nc hoc cc nh khai thc khc trong nc lin k. V th cn phi nghin cu quan h gia cc t hp m tri ph v hot ng ca cc knh ln cn.

3.5. CC KNH CA WCDMACc knh ca WCDMA c chia thnh cc loi knh sau y:TS. Nguyn Phm Anh Dng

51

Knh vt l (PhCH). Knh mang s liu trn giao din v tuyn. Mi PhCH c

mt tri ph m nh knh duy nht phn bit vi knh khc. Mt ngi s dng tch cc c th s dng cc PhCH ring, chung hoc c hai. Knh ring l knh PhCH dnh ring cho mt UE cn knh chung c chia s gia cc UE trong mt . Knh truyn ti (TrCH). Knh do lp vt l cung cp cho lp 2 truyn s liu. Cc knh TrCH c sp xp ln cc PhCH Knh Logic (LoCH). Knh c lp con MAC ca lp 2 cung cp cho lp cao hn. Knh LoCH c xc nh bi kiu thng tin m n truyn.

3.5.1. Cc knh logic, LoCHNi chung cc knh logic (LoCH: Logical Channel) c chia thnh hai nhm: cc knh iu khin (CCH: Control Channel) truyn thng tin iu khin v cc knh lu lng (TCH: Traffic Channel) truyn thng tin ca ngi s dng. Cc knh logic v ng dng ca chng c tng kt trong bng 3.2. Bng 3.2. Danh sch cc knh logic Knh logic BCCH (Broadcast Control CCH (Control Channel: Knh iu khin Channel: Knh qung b) iu khin) PCCH (Paging Control Channel: Knh iu khin tm gi) CCCH (Common Control Channel: Knh iu khin chung) DCCH (Dedicated Control Channel: Knh iu khin ring). DTCH (Dedicated Traffic TCH (Traffic Channel: Knh lu lng Channel: Knh ring) lu lng) CTCH (Common Traffic Channel: Knh lu lng chung) Nhm knh ng dng Knh ng xung pht qung b thng tin h thng Knh ng xung pht qung b thng tin tm gi Knh hai chiu pht thng tin iu khin gia mng v cc UE. c s dng khi khng c kt ni RRC hoc khi truy nhp mt mi Knh hai chiu im n im pht thng tin iu khin ring gia UE v mng. c thit lp bi thit lp kt ni ca RRC Knh hai chiu im n im ring cho mt UE truyn thng tin ca ngi s dng. DTCH c th tn ti c ng ln ln ng xung Knh mt chiu im a im truyn thng tin ca mt ngi s dng cho tt c hay mt nhm ngi s dng quy nh hoc ch cho mt ngi s dng. Knh ny ch c ng xung. 52


3.5.2. Cc knh truyn ti, TrCHCc knh lgic c lp MAC chuyn i thnh cc knh truyn ti. Tn ti hai kiu knh truyn ti: cc knh ring v cc knh chung. im khc nhau gia chng l: knh chung l ti nguyn c chia s cho tt c hoc mt nhm cc ngi s dng trong , cn knh knh ring c n nh ring cho mt ngi s dng duy nht. Cc knh truyn ti chung bao gm: BCH (Broadcast channel: Knh qung b), FACH (Fast Access Channel: Knh truy nhp nhanh), PCH (Paging Channel: Knh tm gi), DSCH (Down Link Shared Channel: Knh chia s ng xung), CPCH (Common Packet Channel: Knh gi chung). Knh ring ch c mt knh duy nht l DCH (Dedicated Channel: Knh ring). Knh truyn ti chung c th c p dng cho tt c cc ngi s dng trong hoc cho mt ngi hoc nhiu ngi c th. Khi knh truyn ti chung c s dng pht thng tin cho tt c cc ngi s dng th knh ny khng cn c a ch. Chng hn knh BCH pht thng tin qung b cho tt c cc ngi s dng trong . Khi knh truyn ti chung p dng cho mt ngi s dng c th, th cn pht nhn dng ngi s dng trong bng (trong bn tin s c pht). Knh PCH l knh truyn ti chung c s dng tm gi mt UE c th s cha thng tin nhn dng ngi s dng bn trong bn tin pht. Danh sch cc knh truyn ti v ng dng ca chng dc cho bng 3.3. Bng 3.3. Danh sch cc knh truyn ti Knh truyn ti DCH (Dedicated Channel: Knh ring) BCH (Broadcast Channel: Knh qung b) FACH (Forward Access Channel: Knh truy nhp ng xung) PCH (Paging Channel: Knh tm gi) RACH (Random Access Channel) CPCH (Common Packet Channel: Knh gi chung) DSCH (Dowlink Shared Channel: Knh chia s ng xung) ng dng Knh hai chiu c s dng pht s liu ca ngi s dng. c n nh ring cho ngi s dng. C kh nng thay i tc v iu khin cng sut nhanh Knh chung ng xung pht thng tin qung b (chng hn thng tin h thng, thng tin ) Knh chung ng xung pht thng tin iu khin v s liu ca ngi s dng. Knh chia s chung cho nhiu UE. c s dng truyn s liu tc thp cho lp cao hn Knh chung dng xung pht cc tn hiu tm gi Knh chung ng ln pht thng tin iu khin v s liu ngi s dng. p dng trong truy nhp ngu nhin v c s dng truyn s liu thp ca ngi s dng Knh chung ng ln pht s liu ngi s dng. p dng trong truy nhp ngu nhin v c s dng trc ht truyn s liu cm. Knh chung ng xung pht s liu gi. Chia s cho nhiu UE. S dng trc ht cho truyn dn s liu tc cao.


53

Cc knh logic c chuyn thnh cc knh truyn ti nh cho trn hnh 3.6.

Hnh 3.6. Chuyn i gia cc LoCH v TrCH trn ng ln v ng xung

3.5.3. Cc knh vt lMt knh vt l c coi l t hp ca tn s, m ngu nhin, m nh knh v c pha tng i (i vi ng ln). Knh vt l (Physical Channel) bao gm cc knh vt l ring (DPCH: Dedicated Physical channel) v knh vt l chung (CPCH: Common Physical Channel). Cc knh vt l c tng kt hnh 3.7 v bng 3.4.

Hnh 3.7. Tng kt cc kiu knh vt lTS. Nguyn Phm Anh Dng

54

Bng 3.4. Danh sch cc knh vt l Tn knh DPCH (Dedicated Physical Channel: Knh vt l ring) ng dng Knh hai chiu ng xung/ng ln c n nh ring cho UE. Gm DPDCH (Dedicated Physical Control Channel: Knh vt l iu khin ring) v DPCCH (Dedicated Physical Control Channel: Knh vt l iu khin ring). Trn ng xung DPDCH v DPCCH c ghp theo thi gian vi ngu nhin ha phc cn trn ng ln c ghp m I/Q vi ngu nhin ha phc Khi s dng DPCH, mi UE c n nh t nht mt DPDCH. Knh c s dng pht s liu ngi s dng t lp cao hn Khi s dng DPCH, mi UE ch c n nh mt DPCCH. Knh c s dng iu khin lp vt l ca DPCH. DPCCH l knh i km vi DPDCH cha: cc k hiu hoa tiu, cc k hiu iu khin cng sut (TPC: Transmission Power Control), ch th kt hp khun dng truyn ti. Cc k hiu hoa tiu cho php my thu nh gi hng ng xung kim ca knh v tuyn v thc hin tch sng nht qun. Cc k hiu ny cng cn cho hot ng ca anten thch ng (hay anten thng minh) c bp sng hp. TPC iu khin cng sut vng kn nhanh cho c ng ln v ng xung. TFCI thng tin cho my thu v cc thng s tc thi ca cc knh truyn ti: cc tc s liu hin thi trn cc knh s liu khi nhiu dch v c s dng ng thi. Ngoi ra TFCI c th b b qua nu tc s liu c nh. Knh cng cha thng tin hi tip hi tip (FBI: Feeback Information) ng ln m bo vng hi tip cho phn tp pht v phn tp chn la. Knh chung ng ln. c s dng mang knh truyn ti RACH Knh chung ng ln. c s dng mang knh truyn ti CPCH Knh chung ng xung. C hai kiu knh CPICH: PCPICH (Primary CPICH: CPICH s cp) v S-CPICH (Secondary CPICH: CPICH th cp). P-CPICH m bo tham chun nht qun cho ton b UE thu c SCH, P-CCPCH, AICH v PICH v cc knh nay khng c hoa tiu ring nh cc trng hp knh DPCH. Knh S-CPICH m bo tham kho nht qun chung 55

DPDCH (Dedicated Physical Data Channel: Knh vt l s liu ring DPCCH (Dedicated Physical Control Channel: Knh vt l iu khin ring)

PRACH (Physical Random Access Channel: Knh vt l truy nhp ngu nhin) PCPCH (Physical Common Packet Channel: Knh vt l gi chung) CPICH (Common Pilot Channel: Knh hoa tiu chung)


trong mt phn hoc on cho trng hp s dng anten thng minh c bp sng hp. Chng hn c th s dng S-CPICH lm tham chun cho S-CCPCH (knh mang cc bn tin tm gi) v cc knh DPCH ng xung. P-CCPCH (Primary Common Control Physical Channel: Knh vt l iu khin chung s cp) S-CCPCH (Secondary Common Control Physical Channel: Knh vt l iu khin chung th cp) SCH (Synchrronization Channel: Knh ng b) PDSCH (Physical Downlink Shared Channel: Knh vt l chia s ng xung) AICH (Acquisition Indication Channel: Knh ch th bt) PICH (Page Indication Channel: Knh ch th tm gi) Knh chung ng xung. Mi c mt knh truyn BCH

Knh chung ng xung. Mt c th c mt hay nhiu S-CCPCH. c s dng truyn PCH v FACH Knh chung ng xung. C hai kiu knh SCH: SCH s cp v SCH th cp. Mi ch c mt SCH s cp v th cp. c s dng tm Knh chung ng xung. Mi c nhiu PDSCH (hoc khng c). c s dng mang knh truyn ti DSCH Knh chung ng xung i cp vi PRACH. c s dng iu khin truy nhp ngu nhin ca PRACH. Knh chung ng xung i cp vi S-CCPCH (khi knh ny mang PCH) pht thng tin kt cui cuc gi cho tng nhm cuc gi kt cui. Khi nhn c thng bo ny, UE thuc nhm kt cui cuc gi th n s thu khung v tuyn trn S-CCPCH Knh chung ng xung i cp vi PCPCH iu khin truy nhp ngu nhin cho PCPCH

AP-AICH (Access Preamble Acquisition Indicator Channel: Knh ch th bt tin t truy nhp) CD/CA-ICH (CPCH Collision Detection/ Channel Assignment Indicator Channel: Knh ch th pht hin va chm CPCH/n nh knh) CSICH (CPCH Status Indicator Channel: Knh ch th trng thi CPCH)

Knh chung ng xung i cp vi PCPCH. c s dng iu khin va chm PCPCH

Knh chung ng xung lin kt vi AP-AICH pht thng tin v trng thi kt ni ca PCPCH


56

Cc cc knh truyn ti c chuyn thnh cc knh vt l nh trn hnh 3.8.

Hnh 3.8. Chuyn i gia cc knh truyn ti v cc knh vt lHnh 3.9 cho thy vic ghp hai knh truyn ti ln mt knh vt l v cung cp ch th li cho tng khi truyn ti ti pha thu.

TFI= Transport Format Indicator: Ch th khun dng truyn ti TFCI= Transport Format Combination Indicator: Ch th kt hp khun dng truyn ti

Hnh 3.9. Ghp cc knh truyn ti ln knh vt l


57

3.5.4. Qu trnh truy nhp ngu nhin RACH v truy nhp gi CPCHQu trnh truy nhp ngu nhin RACH v truy nhp gi CPCH c cho trn hnh 3.10a v 3.10b.

Hnh 3.10. Cc th tc truy nhp ngu nhin RACH v truy nhp gi Cc tr tc truy nhp ngu nhin trn hnh 3.10a nh sau. UE khi xng th tc truy nhp ngu nhin RACH bng cch pht i mt AP (tin t truy nhp). Nu chp nhn (OK), nt B pht AICH (ch th pht hin bt) n UE. Sau UE c th pht bn tin trn knh RACH (knh truy nhp ngu nhin). Cc th tc truy nhp ngu nhin CPCH nh sau. Da trn thng tin kh dng ca tng knh PCPCH do CSICH thng bo, UE khi xng th tc truy nhp CPCH trn knh cha s dng bng cch pht i mt AP (tin t truy nhp). Nu c nt B chp nhn (OK) UE pht i mt CP (tin t pht hin va chm) thng bo rng n chim knh ny. Cui cng nt B pht i CD/CA-ICH (ch th pht hin va chm v n nh knh) n UE. Sau UE c th pht gi trn knh CPCH (knh gi chung)

3.5.5. Th d v bo hiu thit lp cuc gi s dng cc knh logic v truyn tiHnh 3.11 cho thy bo hiu thit lp lp cuc gi s dng knh logic v knh truyn ti. u tin UE s dng knh logic CCCH truyn trn knh truyn ti RACH yu cu ng truyn bo hiu (RRC). RNC tr li bng knh logic CCCH trn knh truyn ti FACH. Sau khi c kt ni RRC, UE s trao i bo hiu vi RNC qua knh logic DCCH trn knh truyn ti DCH. Sau khi nhn c lnh "truyn trc tip" t UE, RNC pht lnh yu cu dch v CM (Connection Management: qun l kt ni) trn giao thc RANAP (Radio Access Application Part: phn ng dng truy nhp mng v tuyn) khi u bo hiu thit lp knh mang lu lng Ty thuc vo yu cu ca UE lnh bo hiu ny c th c chuyn n MSC hoc SGSN (trong trng hp xt l MSC). Sau khi thc hin cc th tc an ninh, cc th tc thit lp knh mang c thc hin.


58

Hnh 3.11. Bo hiu thit lp cuc gi.

3.6. CU TRC KNH VT L RINGCu trc knh vt l ring c trnh by trn hnh 3.12. Trong m hnh ny mi cp hai bit th hin mt cp I/Q (mt k hiu) ca iu ch QPSK. T hnh v ta thy, cu trc khung bao gm mt chui cc khung v tuyn, mi khung bao gm 15 khe (di 10 ms, cha 38400 chip) v mi khe cha 2560 chip (di 0,667 ms) bng mt chu k iu khin cng sut (tn s iu khin cng sut l 1500 ln trong mt giy).


59

Hnh 3.12. Cu trc knh vt l ring cho ng ln v ng xung Cu trc knh vt l ring ng ln cho mt khe (mt chu k iu khin cng sut) c cho trn hnh 3.12. Thng tin ring lp cao hn bao gm s liu ngi s dng v bo hiu c mang bi DPDCH ng ln v thng tin iu khin to ra bi lp 1 c mang bi DPCCH. DPCCH bao gm cc k hiu hoa tiu quy nh trc (c s dng c tnh knh v tch sng nht qun), cc lnh iu khin cng sut (TPC: Transmit Power Control), thng tin phn hi (FBI: Feedback Information) cho phn tp pht vng kn v k thut phn tp chn trm (SSDT: Site Selection Diversity Technique), TFCI (ty chn). C th khng c, mt hay mt s (nhiu nht l 6) knh DPDCH trn mt lin kt v tuyn, nhng ch c mt DPCCH cho lin kt ny. DPDCH (hoc cc DPDCH) v DPCCH c ghp chung theo m I/Q vi ngu nhin ha phc. Cu trc knh vt l ring ng xung c m t trn hnh 3.12.Trn ng xung knh ring (DPCH) ng xung bao gm DPDCH ng xung v DPCCH ng xung ghp theo thi gian vi ngu nhin ha phc. S liu ring c to ra ti cc mc cao hn trn DPDCH c ghp theo thi gian vi cc bit hoa tiu, cc lnh TPC v cc bit TFCI (ty chn) c to ra ti lp vt l. TFCI c th c hoc khng c, nu khng c cc bit TFCI, DTX (pht khng lin tc) c s dng trong trng tng ng.

3.7. S TNG QUT MY PHT V MY THU WCDMAHnh 3.13 cho thy s khi ca my pht v tuyn (hnh 3.13a) v my thu v tuyn (3.13b) trong W-CDMA. Lp 1 (lp vt l) b sung CRC cho tng khi truyn ti (TB: Transport Block) l n v s liu gc cn x l nhn c t lp MAC pht hin li pha thu. Sau s liu c m ho knh v an xen. S liu sau an xen c b sung thm cc bit hoa tiu v cc bit iu khin cng sut pht (TPC: Transmit Power Control)), c sp xp ln cc nhnh I v Q ca QPSK v c tri ph hai lp (tri ph v ngu nhin ho). Chui chip sau ngu nhin ho c gii hn trong bng tn 5 MHz bng b lc Niquist cosin tng cn hai (h s dc bng 0,22) v c bin i vo tng t bng b bin i s vo tng t (D/A) a ln iu ch vung gc cho sng mang. Tn hiu trung tn (IF) sau iu ch cTS. Nguyn Phm Anh Dng

60

bin i nng tn vo sng v tuyn (RF) trong bng tn 2 GHz, sau c a ln khuych i trc khi chuyn n anten pht vo khng gian. Ti pha thu, tn hiu thu c b khuych i i tp m thp (LNA) khuych i, c bin i vo trung tn (IF) thu ri c khuych i tuyn tnh bi b khuych i AGC (t iu khuych). Sau khuych di AGC tn hiu c gii iu ch c cc thnh phn I v Q. Cc tn hiu tng t ca cc thnh phn ny c bin i vo s ti b bin i A/D, c lc bi b lc Nyquist cosine tng cn hai v c phn chia theo thi gian vo mt s thnh phn ng truyn c cc thi gian tr truyn sng khc nhau. My thu RAKE chn cc thnh phn ln hn mt ngng cho trc). Sau gii tri ph cho cc thnh phn ny, chng c kt hp bi b kt hp my thu RAKE, tn hiu tng c gii an xen, gii m knh (gii m sa li), c phn knh thnh cc khi truyn ti TB v c pht hin li. Cui cng chng c a n lp cao hn.

Hnh 3.13. S khi my pht tuyn (a) v my thu v tuyn (b)

3.8. PHN TP PHTKhi nhiu anten thu c s dng, ta ni my thu s dng phn tp anten thu (Rx). Phn tp Rx c th c s dng ti nt B tng dung lng ng ln v vng ph sng. Do gi thnh v khng gian chim ln, phn tp anten thu khng ph bin ti my u cui. khc phc nhc im ny WCDMA s dng phn tp pht


61

cho my u cui. Tn ti hai k thut phn tp pht WCDMA: Phn tp vng h v phn tp vng kn.

3.8.1. Phn tp vng hPhn tp pht vng h s dng b m ha c gi l STTD (Space time Transmit Diversity: phn tp pht khng gian thi gian). S my pht v my thu s dng STTD c cho trn hnh 3.14a v 3.14b.

MF: Matched Filter: B lc phi hp Hnh 3.14. Phn tp pht vng h ca WCDMA STTD c xy dng trn c s m Alamouti nh sau : x x 2 X(x1 , x 2 ) = 1 x x 2 1

(3.1)

trong ct 1 cha cc k hiu c pht i t anten 1 cn ct 2 cha cc k hiu c pht i t anten 2. Cc k hiu ny l cc k hiu iu ch QPSK (xem hnh 3.15).


62

Hnh 3.15. B iu ch STTD s dng m khi khng gian thi gian trc giao (OSTBC) 2x2.

3.8.2. Ch vng knR3 v R4 s dng hai khi nim phn tp pht vng kn. Trong c hai ch ny, thng tin ng chnh pha c pht trn mt knh hi tip nhanh (tc 1500 bps) cho php chn 4 hoc 16 kh nng trng s bp sng. C hai khi nim ny u c th coi l truyn dn nht qun (to bp thch ng knh) vi s dng cn bng knh v cc chin lc bo hiu hi tip khc nhau. Kin trc my pht v my thu nt B c cho trn hnh 3.16a v 3.16b.

Hnh 3.16. Phn tp pht vng kn ca WCDMA Trong c hai ch trng s pht c la chn theo th tc d

thông tin di động

Documents