Tieu Luan 3G Final

8/6/2019 Tieu Luan 3G Final

1/27


2/27

Vin i hc mH Ni

Tiu lun : Nng cp cng ngh h GMS ln 3G v cu trc mng liGio vin hng dn : Tin sPhm Cng HngSinh vin : ng Hong Tng Lp cao hc kha I http://www.ebook.edu.vn Trang2

PH LC

I. Slc vmngin thoi di ng 2

II. Cc yu tkthut trong mng di ng 4

2.1 Lp cc thit bu cui ( terminal ) 5

2.2 Lp truy nhp ( Access ) 5

2.3 Lp li (core) 6

2.4 Lp dch v 6

III. SPHT TRIN CA MNG DING 7

3.1 Spht trin gia cc thh thng tin 7

3.2 Xu hng cng ngh thng tin khng dy 8

III. NNG CP CNG TRONG NGHH GSM LN 3G 10

3.1 Hin trng h thng thng tin di ngnc ta 10

3.2 Nghin cu chuyn t2G ln 3G 10

3.2.1 Trin khai nng cp csh tng 113.2.2 Spht trin lin mch 13

3.2.3 Vic vn hnh ca mt mng 3G 14

3.3 M hnh trin khai 3G 16

3.3.1 Trin khai nhanh chng WCDMA trn ton mng 16

3.3.2 Trin khai WCDMA dn dn: 17

3.3.3 Trin khai 3G sau: 17


3/27

Vin i hc mH Ni



4/27

Vin i hc mH Ni


I. SLC VMNG IN THOI DI NGNh chng ta bit mng 2G (Second-Generation wireless telephone

technology) l mng in thoi di ng th h th 2. c im khc bit ni bt

gia mng in thoi th hu tin (1G) v mng 2G l s chuyn i tinthoi dng tn hiu tng t sang tn hiu s. Ty theo k thut a truy cp,

mng 2G c th phn ra 2 loi: mng 2G da trn nn TDMA (Time Division

Multiple Access) v mng 2G da trn nn CDMA (Code Division Multiple

Access).

Trong , TDMA l phng thc a truy c p phn chia theo thi gian cn

CDMA l phng thc a truy cp phn chia theo m. Trong k thut CDMA,tn hiu ca mi ngi dng (user) sc dn tri (spreading) bng mt m

xc nh trc giao (hoc gi trc giao) vi nhau. Tn hiu truyn s l tn hiu

chng chp ca nhiu ngi dng khc nhau theo thi gian v trn cng mt

bng tn s.

Cn mng 3G (third-generation technology) l cng ngh truyn thng th h

th ba, cho php truyn c d liu thoi v d liu ngoi thoi (ti d liu, gi

email, tin nhn nhanh, hnh nh...). V im ni bt nht ca mng 3G so vi

mng 2G nm kh nng cung ng truyn thng gi tc cao nhm trin khai

cc dch v truyn thng a phng tin trn mng di ng. Tc truyn d

liu mng 3G s cao hn rt nhiu so vi mng 2G.

Hin nay, ti Vit Nam pht trin cng ngh 3G l mt trong vn c nhiu

chuyn gia cng nh cc nh u t quan tm.Theo nh gi ca cc chuyn gia

vin thng, vic chuyn t 2G sang 3G l iu khng th trnh c trong xu

th hin nay v ngi s dng mun hng cc dch va phng tin phong

ph v dch v d liu tc cao. Nhng chic in thoi di ng th h 2G s

hot ng c trn mng 3G nu ngi s dng ng k dch v. Theo nhiu

chuyn gia, c th s c nhng chic in thoi chuyn dng trn mng 3G v

chng khng khc my so vi cc loi in thoi hin thi.


5/27

Vin i hc mH Ni


Tng t nh s hi t ca mng cnh theo hng NGN, cc cng ngh di

ng cng ang trong qu trnh hi t nhm p ng cc yu cu ca khch

hng di ng v bng thng v cht lng dch v vi vic ra i mng di ng

th h 2.5G, 3G...

Lu lng cc giao dch (voice/data) trn mng di ng cng tng rt nhanh

trong thi gian gn y v t nm 1999 vt nhu cu trn ng hu tuyn.

Cc nghin cu ti Vit Nam v mng di ng cn rt hn ch v thng ch l

nghin cu l thuyt m t c nhng sn phm thc t. Nguyn nhn su xa ca

vn l ch mng di ng cha ng nhiu k thut phc tp kh chng

trong iu kin hin nay ca Vit Nam.

II. / CC YU T K THUT TRONG MNG DI NG

Tng t nh trong mng cnh, mng di ng bao gm cc lp: lp cc u

cui ngui s dng (terminal), lp truy nhp (access), lp mng li (core), lp

cung cp dch v (services) vi s tham gia ca cc tc nhn: Khch hng

(customer-subscriber), nh cung cp dch v (service provider) v nh cung cp

ni dung (content provider).

2.1Lp cc thit bu cui ( terminal )

L p cc u cui di ng c chc nng giao din vi ngi s dng v truy

nhp dch v t mng li, mt s chc nng bao gm trong u cui di ng:

cc giao thc truy nh p v tuyn, cc giao thc truy nhp dch v (call/data),


6/27

Vin i hc mH Ni


bo hiu u cui n u cui, nhn thc (SIM), framework cho cc dch v

ca ngi s dng,...

2.2 Lp truy nhp ( Access )

Lp truy nhp trong mng di ng s dng truy nhp v tuyn thay th cho cc

phng thc s dng dy nh trong mng cnh.

Cc giao thc truy nhp knh v tuyn tch hp trong u cui v cc trm thu

pht v thc hin mt s chc nng cbn: Truyn/nhn d liu qua sng v

tuyn vi mc tin cy chp nhn c, m ho v gii m, iu khin nng

lng pht ca u cui, qun l ti nguyn v tuyn, iu khin chuyn giao,...

Lp truy nhp chnh l ca ng gy ra nhiu gii hn trong vic nng cao cht

lng v bng thng cho cc dch v. V vy, cc nghin cu gii quyt vn

lin quan n lp ny lun l im c quan tm nht trong cc nghin cu v

mng di ng. Cc nghin cu theo cc hng khc nhau to ra cc k thut

truy nhp khc nhau: phn knh theo thi gian, phn knh theo tn s hay phn

knh theo m. Cc phng thc ny l c scho cc kiu mng di ng khc

nhau TDM, GSM, CDMA.. V im khc bit nht gia cc mng di ng cngnm lp ny.

2.3 Lp li (core)

L p li (core) ca mng di ng thc hin cc chc nng: chuyn mch cc

phin giao dch, qun l di ng, bo hiu thit lp cuc gi gia mng core v

u cui, bo hiu lin mng gia cc mng core mobile, bo hiu lin mng vi

cc mng c...

Lp li bao gm cc thnh phn: Chuyn mch (MSC), qun l thu bao (HLR,

VLR, EIR, UAC), cng giao ti p lin mng (GMSC). Cc thnh phn l p li

thc hin qun l thu bao nh EIR, HLR, VLR thng tng t nhau trong cc

mng di ng v cc th h di ng v chng thng l phn qun tr CSDL

khng lin quan n k thut mng. Cc thnh phn chuyn mch v cng giao


7/27

Vin i hc mH Ni


tip lin mng ca cc mng GSM v CDMA ging nhau v nguyn tc v khc

nhau trong nhng giao thc ti cc giao din c th.

2.4 Lp dch v

Lp dch v c chc nng cung cp cc dch v ngoi cc dch v cbn cho

thu bao, lp ny nh ngha v dch v v cc yu cu c thi vi tng dch

v. Cc thc th ca lp ny cng vi thnh phn khc ca mng di ng to

thnh mt tng th cung cp dch v: SMSC, WAPGW, MMSC, Streaming

server..

III. SPHT TRIN CA MNG DI NG

3.1 Spht trin gia cc th h thng tin

Trn mng cnh (fixed) ang din ra mt qu trnh hi t v cng ngh v

dch v gia mng vin thng v Internet da trn k thut chuyn mch gi IP,

thut ng NGN- mng th h sau c nhc n rt nhiu trong nhng nm gny. Internet cng ang pht trin tng ngy, t cc modem tc thp, n nay

pht trin nhiu phng thc truy nhp tc cao v linh hot hn trong

Wireless-LAN thc s l mt thch thc vi mng di ng tuy kh nng di ng

cn hn ch.

ng trc s pht trin ca Internet cng vi cc dch v phong ph mi ca

mng cnh, cc nh cung cp dch v di ng khng th tho mn vi mngdi ng 2G hin ch c ng dng thoi v nhn tin ngn SMS. Nhiu t chc

vin thng ln v cc t chc chun ho quc t c gng a ra mt kin trc

mng di ng mi nhm thch ng linh hot vi s pht trin ca cng ngh IP,

c thp ng tt nhu cu ca khch hng v cc dch v mi. 3GPP l t chc

mv chun ho mng di ng trong th h mi vi vic nghin cu v a ra

cc khuyn ngh cho mng di ng trn con ng tin ti s hi t.


8/27


9/27

Vin i hc mH Ni


xut phng n trin khai th nghim 3G Vit Nam v cng trin khai

th nghim 3G trong phm vi hp trn mng ca Mobifone, Vinaphone.

Cc nh khai thc mng di ng hin ti v mt s nh cung cp dch v di ng

mi (Viettel, SPT, ETC..) thc hin vic nng cp mng hay trang b mi vnda trn l trnh t 2G ln 2.5G ri n 3G m cha mt nh khai thc no c s

u t trc tip vo 3G.

Vi th trng Vit Nam, cng ngh di ng u tin GSM, th h 2G n gin,

ch cho php thoi l chnh. Vic nng cp ln cng ngh GPRS vo cui nm

2003 gip ngi dng bt u lm quen vi nhng ng dng d liu. Cui

nm 2007 va qua, sau khi ng dng EGDE, tc c nng cao hn vinh tc t khong 384 kb/s. Nhng tc thc t vn cn thp khin cc

dch v da trn nn d liu khng th pht trin v bng n mnh nh dch v

thoi hin nay.

Trn th gii by gicn 2 th h cao cp ca h GSM vn cha c ng dng

ti th trng Vit Nam, l WCDMA - th h 3G vi tc 2Mbps v HSPA

(HSDPA & HSUPA) th h 3,5G vi kh nng truyn ln n 14,4 Mbps. y

l nhng cng ngh tin tin ang c ng dng rng ri trn th gii vi hn

200 triu thu bao, trn 220 mng thuc 94 quc gia, chim 2/3 thu bao 3G trn

ton cu (GSA, 6/2008).


10/27

Vin i hc mH Ni


III. NNG CP CNG TRONG NGH H GSM LN 3G

3.1 Hin trng h thng thng tin di ng nc ta

Qua mt s sch bo, tp ch v thng tin t mt s nh cung cp dch v thng

tin di ng th mng di ng trong thi gian trc y ch tp trung vo cc vn

l thuyt v vic trin khai cng ngh hn l vic nghin cu pht trin sn

phm. S hn ch ny bn cnh vic l hn ch chung nc ta trong nghin

cu v vin thng ni chung cn do s tp trung cc cng ngh phc tp nht v

k thut mng di ng v cc k thut chuyn dng thc hin nm ngoi kh

nng tip cn ca chng ta.

Trong mt vi nm tr li y c mt s nghin cu theo hng sn phm

trn mng di ng v ln u tin cc sn phm nghin cu ny tham gia

hoc c kh nng tham gia vo cu trc mng v cung cp dch v cho cc mng

di ng VN 2G v 2,5G. C th kn CDIT vi cc sn phm: H thng

nhn tin ngn-SMSC, H thng cung cp dch v bo cuc gi b l, h thng

thng bo thu bao chuyn vng (2G), H thng nhn tin a phng tin

MMSC, H thng cung cp dch v WAP2.0, H thng cung cp dch v Video-

streaming (2.5G).

Nhn chung, cc sn phm nghin cu ny tp trung lp cung cp dch v. Cc

nghin cu v cc mng li, mng truy nhp v u cui vn hu nh rt t c

cp n.

3.2 Nghin cu chuyn t2G ln 3G

M hnh t chc ca cc mng vin thng t trc ti nay c t chc theo

hng dc, ngha l mi mng phc v cho mt loi hnh dch v ring. Trong xu

hng pht trin ca mng vin thng p ng vi tnh hnh mi, m hnh t

chc mng th mi NGN c xut s dng ( chuyn m hnh t chc mng

t hng dc sang cu hnh phn l p c s tch bit gia cc l p : truy nhp,


11/27

Vin i hc mH Ni


truyn dn - chuyn mch, iu kin, dch v. Mng NGN s dng gi IP l ch

o vi m hnh phn lp, vic pht trin dch v trnn d dng hn.

Trong u kin hin nay, nu thay th ton b mng 2G bng cc cng ngh,

thit b 3G th s rt tn km, nht l cc cng nghang s dng lp u cuiv lp truy nhp v tuyn. Mc d Wireless LAN l mt xu th nhng vn cn

nhiu hn chang tip tc c khc phc trong tng lai.

3.2.1 Nng cp csh tng

Cc cng ngh GSM/GPRS/EDGE c cng mt c snn tng l k thut

truy cp TDMA v FDMA v vy hot ng trn cng mt bng thng (vi mi

knh bng tn s 200kHz). S nng cp do cng khng qu phc tp.

Khi nng cp ln 3G, cng ngh WCDMA hot ng trn mt k thut truy cp

khc hon ton, l CDMA, do bng tn hot ng s phi tch bit vi

GSM (WCDMA mi knh bng tn s l 5MHz). S cn mt di tn 3G mi

khc vi tn sang hot ng hin nay.

Vic u t mrng bng cch t thm trm pht sng BTS hin nay gp nhiukh khn do vic qun l hnh chnh v s tn km v ti chnh. Mt trm ti

cc khu dn c tng i dy ( v d ti Nng khong cch gn nht gia 2

trm t 200-300m) nu b xung thm trm s dn n nhiu knh v kh ti s

dng tn s.

i mi ta s cn mt thit b thu pht sng BTS hon ton mi, c t tn

l Node B, cng vi n l mt thit b qun l trm gc (BSC) mi, tn l iu

khin mng v tuyn RNC (Radio Network Controller).

i vi mng GSM, chuyn sang m hnh mng phn lp NGN trong giai

on u chuyn sang mng 3G, gii php chuyn mch mm cho di ng (

Mobile SoftSwitch ) s thay th cc MSC truyn thng bng cc chuyn mch

mm, trong c s tch bit gia phn iu khin v phn chuyn mch. Cng

ngh chuyn mch gi c a v s dng song song vi cng ngh chuyn


12/27

Vin i hc mH Ni


mch knh truyn thng, iu ny s gip cho vic chuyn i cng nghtn

km hn trong qu trnh nng cp mng.

Do tnh k tha khi nng cp, h thng mng li (tng i chuyn mch) hin

hu vn c thc s dng kt ni vi mng v tuyn (Node B v RNC)ca cng ngh WCDMA mi (Hnh 1).

Hnh 1: Phng n chung mng li

Mt khc, trnh tc ng n mng ang hot ng cng nh m rng

dung lng, mt gii php khc cng c cc nh cung cp s dng l u t

mt h thng mng mi hon ton. (Hnh 2).

Hnh 2: Phng n thm mng li


13/27

Vin i hc mH Ni


Theo thi gian, tt c cc thit b mng li v v tuyn s tch hp chung nh

Hnh 3. Cc thit b BTS, BSC c s ht khu hao hoc di chuyn ra cc vng

su, vng xa khc h trsng GSM/EDGE.

Hnh 3: Phng n tch hp chung

3.2.2 Spht trin lin mch

C mt s nhn xt v s nng cp ln 3G ch l s ghp thm 1 h thng mi

vi cng ngh mi vo h thng c sn. Nhng thc t vic nng cp mng

mang tnh k tha v lin mch nh hnh di

V tuyn GSM- Bng tn 800, 900,

1800, 1900 MHz- Ph sng ton quc

Phn chung :- Mng li- Truyn dn- Trm- in thoi- H thng d liu- H thng vn hng v

un l mn

V tuyn WCDMA- Bng tn 1900, 2100 Mhz.- Ph sng bt u t ccvng th


14/27

Vin i hc mH Ni


y, ngoi h thng v tuyn WCDMA (bao gm RNC v Node B) l

cn u t mi, tt c h thng khc sc tn dng li. Hu ht cc nh sn

xut tng i hin nay u c gii php nng cp h thng mng li, truyn

dn, c s d liu, h thng vn hnh hin hu h tr c GSM v

WCDMA.

Nh vy, mun ph sng 3G u, cc nh cung cp dch v st thit b thu

pht sng 3G khu vc (s dng nh trm c sn) v ni v tng i. Tt

nhin, vi s lng hn 3000 - 4000 nh trm/1 mng nh hin nay ti Vit

Nam, vic u t 3G ph sng ton quc khng phi d dng v kh tn km.

Tuy nhin t su t WCDMA ny, vic nng cp ln mng 3,5G HSPA s rtn gin khi ch cn nng cp phn mm, tng t nh khi ngi ta nng cp t

GPRS ln EDGE, l ngi dng c th s dng c dch v di ng khng

thua km g mng ADSL hu tuyn hin nay.

- Tuy nm trn 2 thit b khc nhau, s vn hnh ca 2 h thng v tuyn bao

gm GSM v WCDMA cng sc qun l thng nht, m bo chuyn giao

lin mch gia 2 h thng. Cuc gi s vn m bo duy tr khi chuyn bng tn

v chuyn cng ngh, iu ny s xy ra khi ngi dng di chuyn ngoi vng

ph sng ca mt cng ngh hoc b qu ti.

Nhtnh lin mch ny, vic s dng bng thng s rt hiu qu (c siu tit,

phn b qua li gia cc cuc gi trn cc bng tn), tc s gim nghn mng;

cc thit b sc tn dng ti a (dng chung ti nguyn cho c hai h thng);

v vic u t WCDMA khng cn phi ng lot ton mng.

3.2.3 Vic vn hnh ca mt mng 3G

Ty vo mc pht trin ca tng th trng v tng mng, m hnh

trin khai 3G ca mi nh khai thc s khc nhau. Hoc ph sng ng lot 3G

trn ton th trng, hoc ph sng dn dn t khu vc th ri mrng dn.

Khi ti vng 3G, s tn ti mt lot cc cng ngh GSM, GPRS, EDGE,


15/27

Vin i hc mH Ni


WCDMA (v c HSPA nu nng c p), ty thuc vo cng ngh ca chic

in thoi m bn ang s dng, bn c th tn hng tc tng ng.

Ly v din thoi ca bn l chic GSM (hoc GPRS, EDGE), cuc gi ca

bn s vn chy trn bng tn c, n trm thu pht sng GSM v theo h thngtng i chuyn mch c. Tng ng vi cng ngh ca chic in thoi

(GSM/GPRS/EDGE) m bn c th thng thc tc truy cp khc nhau.

Nu trong tay c chic in thoi 3G (WCDMA hoc HSPA, nh chic iPhone

3G chng hn), th cuc gi s theo bng tn mi, trm Node B mi v chy v

tng i. Cu hnh chic in thoi 3G ny chc chn s phi hot ng c

vi 2G, tc l in thoi phi a ch GSM/GPRS/EDGE/WCDMA iuny l bt buc v vng ph sng 2G v 3G khng ng nht, nu ra ngoi vng

ph 3G, bn s vn lin lc c nhvo sng 2G c sn.

Vi mt mng a ch nh vy, cc tng i s c 3 cchiu khin, cung

cp loi cng ngh thch hp cho cc cuc gi:

- Nh cung cp quy nh v chnh sch dch v: mi loi cuc gi sc

gn 1 loi cng ngh, v d cc cuc gi thoi si theo mng GSM, cuc gid liu s theo mng 3G.

- iu khin cn bng ti gia cc ch: v d khi cuc gi trn bng tn

GSM qu ti, mt s thu bao sc chuyn qua WCDMA tip tc cuc

gi, hoc ngc li.

- Gi cc, loi hnh thu bao ca ngi dng: mi thu bao s thuc mt

nhm khch hng vi u tin khc nhau. Thu bao vng sc u tin gn

vo ch c ti thp nht hoc tc cao nht. Trong khi thu bao thng ch

c s dng dch v tc thp, hoc vn s dng GSM ngay c trong vng

ph WCDMA.

hiu hn s vn hnh ny, chng ta hy cng xem mt minh ha sau. Mt

ngi dng vi in thoi a ch GSM/WCDMA i t trung tm thnh ph


16/27

Vin i hc mH Ni


i ra vng min no . Mng thu bao l GSM vi vng ph sng EDGE ton

quc, ti mt s thnh ph c sng WCDMA.

Khi i, thu bao gi cho mt tu bao khc, sau thu bao gi mt on phim

video trong khi vn tip tc cuc ni chuyn (WCDMA cho php thc hin 2cuc gi d liu v thoi cng lc ). Khi ra khi thnh ph, ht sng WCDMA,

tng i s chuyn cuc gi thoi sang mng GSM v chuyn cuc gi video

sang mng EDGE. Thu bao ny s thy cht lng cuc gi video gim i

trong khi cht lng cuc gi s khng i.

3.3 M hnh trin khai 3G

Ni v vic nng cp 3G khng th khng bn n m hnh, hay chin lc

trin khai 3G. C 3 kh nng c th xy ra :

- Trin khai nhanh chng WCDMA trn mng ton quc

- Trin khai WCDMA t t

- Trin khai 3G sau.

3.3.1 Trin khai nhanh chng WCDMA trn ton mng:C nhiu nguyn nhn cc nh cung cp chn phng n ny: mc cnh

tranh th trng cao; theo yu cu ca nh nc; th trng c nhu cu dch v

d liu cao; tnh hnh ti chnh mnh; dung lng mng GSM hin ti ang b

hn ch; t l ri mng cao; tham vng chim thm th phn v nng cao ch s

doanh thu trn mt thu bao (ARPU).

Nu vng ph sng 3G th rng khp m khch hng li khng c thit b

s dng th cng v ngha. V vy, mun chin lc ny thnh cng, cc nh

khai thc phi c mt chnh sch pht trin thu bao tng ng: khuyn khch

khch hng thay my mi, tip th cc thit b mi gn vi dch v d liu v.v

3.3.2 Trin khai WCDMA dn dn:


17/27

Vin i hc mH Ni


ph sng WCDMA bt u t vng th ri lan ta dn ra, trong khi vn

tip tc u t GSM nng cao dung lng dch v thoi v dch v d liu

tc thp GPRS. Cc l do chn chin lc ny: kh nng pht trin ca

GSM v GPRS vn cn cao; cht lng v dung lng ca GSM v GPRS c

vn (cn phi u t ci thin phc v khch hng 2G); mng GSM v s

thu bao qu ln; in thoi 2G vn cn nhiu; th trng d liu di ng ch

mi pht trin; tnh hnh ti chnh n nh.

Cc thit bu cui a ch GSM/GPRS/WCDMA v vy cng sc gii

thiu, tip th dn dn, ph thuc vo nhu cu v kh nng ca khch hng.

3.2.3 Trin khai 3G sau:Khi nhu cu th trng v dch v d liu cao cn thp, nhu cu v thoi vn l

ch yu v tip tc pht trin, th nh cung cp ti th trng ny ch cn pht

trin ln EDGE l va . Vic nng cp ln WCDMA sc cn nhc trong

tng lai. Tuy nhin khi u t h tng mng GSM hoc GPRS, nh khai thc

ny phi ch chn h thng h trtt vic nng cp WCDMA trong tng lai.


18/27

Vin i hc mH Ni


III. Mng li NGN ( Next Generation Network)

NGN l mng hi t c thoi, video v d liu trn cng mt csh tng datrn nn tng IP, lm vic trn c hai phng tin truyn thng v tuyn v hutuyn. NGN l s tch hp cu trc mng hin ti vi cu trc mng a dch vda trn c s h tng c sn, vi s h p nht cc h thng qun l v iukhin. Cc ng dng cbn bao gm thoi, hi ngh truyn hnh v nhn tin hpnht (unified messaging) nh voice mail, email v fax mail, cng nhiu dch vtim nng khc.

Cc c im ca NGN:

1. S dng cng ngh chuyn mch mm (SW-SoftSwitch) thay thcc thit b tng i chuyn mch phn cng (hardware) cng knh.Cc mng ca tng dch v ring rc kt ni vi nhau thngqua siu khin ca mt thit b tng i duy nht, thit b tngi ny da trn cng ngh SW c v nh l 'tri tim' ca NGN.

2. Mng hi t thoi v d liu, cnh v di ng. Cc loi tn hiuc truyn ti theo k thut chuyn mch gi, xu hng sp tiang tin dn ln s dng mng IP vi k thut QoS nh MPLS.

3. Mng bng thng rng cung cp a dch v: Mng truyn dnquang vi cng ngh WDM (Wavelength Division Multiplexing)hay DWDM (dense WDM).

3.1 CU TRC MNG NGN


19/27

Vin i hc mH Ni


Cu trc mng NGN bao gm 5 lp chc nng: lp truy nhp dch v (serviceaccess layer), l p chuyn ti dch v (service transport/core layer), lp iukhin (control layer), lp ng dng/dch v (application/service layer) v lpqun l (management layer). Hnh 1 th hin cu trc ca NGN.

3.1.1 Lp ng dng/dch v

Lp ng dng v dch v cung cp cc ng dng v dch v nh dch v mngthng minh IN (Intelligent network), tr tin trc, dch v gi tr gia tngInternet cho khch hng thng qua lp iu khin... H thng ng dng v dchv mng ny lin kt vi lp iu khin thng qua cc giao din mAPI. Nhgiao din mny m nh cung cp dch v c th pht trin cc ng dng vtrin khai nhanh chng cc dch v trn mng. Trong mi trng pht trin cnhtranh s c rt nhiu thnh phn tham gia kinh doanh trong lp ny.

3.1.2 Lp iu khin

Lp iu khin bao gm cc h thng iu khin kt ni cuc gi gia ccthu bao thng qua vic iu khin cc thit b chuyn mch (ATM+IP) ca lpchuyn ti v cc thit b truy nhp ca lp truy nhp. Lp iu khin c chcnng kt ni cuc gi thu bao vi lp ng dng/dch v. Cc chc nng nhqun l, chm sc khch hng, tnh cc cng c tch h p trong lp iukhin.

L p chuyn ti dch v

Bao gm cc nt chuyn mch(ATM+IP) v cc h thngtruyn dn (SDH, WDM), thchin chc nng chuyn mch,nh tuyn cc cuc gi giacc thu bao ca l p truy nhp

di s iu khin ca thit biu khin cuc gi thuc lpiu khin. Hin nay ang cnnhiu tranh ci khi s dngATM hay MPLS cho lp

chuyn ti ny.

3.1.3 Lp truy nhp dch v

Bao gm cc thit b truy nhp cung cp cc cng kt ni vi thit bu cui


20/27

Vin i hc mH Ni


thu bao qua h thng mng ngoi vi cp ng, hoc cp quang, hoc thng quami trng v tuyn (thng tin di ng, v tinh, truy nhp v tuyn cnh...)

3.1.4 Lp qun l

y l lp c bit xuyn sut cc lp trn. Cc chc nng qun l c chtrng l: qun l mng, qun l dch v, qun l kinh doanh.

3.2 CC THNH PHN CA MNG NGN

Mi tng quan gia cu trc phn lpchc nng v cc thnh phn chnh ca mngNGN c m t trong hnh 2.

Theo hnh 2 ta nhn thy, cc loi thitb u cui kt ni n mng truy nhp(Access Network), sau kt ni n cc cngtruyn thng (Media Gateway) nm bin camng trc. Thit b quan trng nht ca NGNl SW nm tm ca mng trc (cn hay gil mng li). SW iu khin cc chc nngchuyn mch v nh tuyn qua cc giao thc.Cc giao thc ny sc xem xt kphnsau. Hnh 3 lit k chi tit cc thnh phntrong mng NGN cng vi cc c im ktni ca n n cc mng cng cng (PSTN).

3.2.1 Thit b SW ( SoftSwicth )

Thit b SW l thit bu no trong mng NGN. N lm nhim viu khin

cuc gi, bo hiu v cc tnh nng to mt cuc gi trong mng NGN hoc


21/27

Vin i hc mH Ni


xuyn qua nhiu mng khc (v d PSTN, ISDN). SW cn c gi l CallAgent (v chc nng iu khin cuc gi ca n) hoc Media GatewayController - MGC (v chc nng iu khin cng truyn thng - MediaGateway).

Thit b SW c kh nng tng tc vi mng PSTN thng qua cc cngbo hiu (Signalling Gateway) v cng truyn thng (Media Gateway). SW iukhin cuc gi thng qua cc bo hiu, c hai loi chnh:

- Ngang hng (peer-to-peer): giao ti p gia SW v SW, giao thc sdng l BICC hay SIP.

- iu khin truyn thng: giao tip gia SW v Gateway, giao thc sdng l MGCP hay Megaco/H.248.

3.2.2 Cng truyn thng

Nhim v ch yu ca cng truyn thng (MG - Media Gateway) lchuyn i vic truyn thng t mt nh dng truyn dn ny sang mt nhdng khc, thng thng l t dng mch (circuit) sang dng gi (packet), hoct dng mch analog/ISDN sang dng gi. Vic chuyn i ny c iu khinbng SW. MG thc hin vic m ha, gii m v nn d liu thoi.

Ngoi ra, MG cn h trcc giao tip vi mng in thoi truyn thng(PSTN) v cc giao thc khc nh CAS (Channel Associated Signalling) vISDN. Tm li, MG cung cp mt phng tin truyn thng truyn ti thoi,d liu, fax v hnh nh gia mng truyn thng PSTN v mng gi IP.

3.2.3 Cng truy nhp

Cng truy nhp (AG - Access Gateway) l mt dng ca MG. N c khnng giao tip vi my PC, thu bao ca mng PSTN, xDSL v giao tip vimng gi IP qua giao tip STM. mng hin nay, lu lng thoi t thu bao

c kt ni n tng i chuyn mch PSTN khc bng giao tip V5.2 thngqua cng truy nh p. Tuy nhin, trong mng NGN, cng truy nhp c iukhin t SW qua giao thc MGCP hay Megaco/H.248. Lc ny, lu lng thoit cc thu bao sc ng gi v kt ni vo mng trc IP.


22/27

Vin i hc mH Ni


Hnh 3: Cc thnh phn chnh trong NGN

3.2.4 Cng bo hiu

Cng bo hiu (SG - Signalling Gateway) ng vai tr nh mt cng giaotip gia mng bo hiu s 7 (SS7 - Signalling System 7, giao thc c dngtrong PSTN) v cc im c qun l bi thit b SW trong mng IP. Cng SGi hi mt ng kt ni vt l n mng SS7 v phi s dng cc giao thcph hp. SG to ra mt cu ni gia mng SS7 v mng IP, di siu khin

ca SW. SG lm cho SW ging nh mt im nt bnh thng trong mng SS7.Lu rng SG chiu khin SS7; cn MG iu khin cc mch thoi thit lpbi cch SS7.

3.2.5 Mng trc IP

Mng trc c th hin l mng IP kt hp cng ngh ATM hoc MPLS. Vn s dng ATM hay MPLS cn ang tch thnh 2 xu hng. Cc dch v vng dng trn mng NGN c qun l v cung cp bi cc my ch dch v(server). Cc my ch ny hot ng trn mng thng minh (IN - IntelligentNetwork) v giao tip vi mng PSTN thng qua SS7.

3.3 CC GIAO THC BO HIU TRONG MNG NGN

Cc giao thc v bo hiu trong mng NGN c th hin trong s hnh 4.

3.3.1 Giao thc Megaco/H.248


23/27

Vin i hc mH Ni


Megaco v H.248 ging nhau, u l giao thc iu khin MG. Megaco c pht trin bi IETF (a ra vo cui nm 1998), cn H.248 c a ra vothng 5/1999 bi ITU-T. Sau c IETF v ITU-T cng hp tc thng nht giaothc iu khin MG, kt qu l vo thng 6/2000 chun Megaco/H.248 ra i.

Megaco/H.248 l bo hiu gia SW/MGC vi MG (Trunking MediaGateway, Lines Media Gateway hoc IP Phone Media Gateway). Megaco/H.248iu khin MG kt ni cc lung t ngoi. S iu khin MG caMegaco/H.248 c th hin hnh 5.

Megaco/H.248 tng t vi MGCP v mt cu trc v mi lin h giabiu khin v cng gateway, tuy nhin Megaco/H248 h tra dng hn ccloi mng (v d ATM).

Hnh 4: S cc giao thc

3.3.2 Giao thc BICC

BICC (Bearer Independent Call Control) l giao thc bo hiu gia 2MGC/Call Server, c th l t cc nh cung cp khc nhau, nhm mc ch mbo lu lng thoi dng k thut gi (VoP - Voice over Packet). Theo ITU-T,BICC c thit k c th tch hp hon ton vi cc mng hin hu v btk h thng no c h trvic chuyn ti bn tin nhn thoi.

BICC h trcc dch v bng hp (PSTN, ISDN) mt cch c lp ving truyn v k thut chuyn ti bn tin bo hiu. Bn tin BICC chuyn chc thng tin iu khin cuc gi v iu khin ng truyn. BICC gp phn


24/27

Vin i hc mH Ni


n gin ha cc bo hiu s dng cho vic giao ti p hot ng gia mngtruyn thng vo mng NGN. Ni cch khc, mng NGN vi nn tng mngchuyn mch gi c th cung cp y cc dch v bng hp thng qua bohiu BICC.

Trong BICC, giao thc bo hiu iu khin ng truyn ph thuc vocng nghng truyn lp di nh ATM, IP/MPLS.

Hnh 6 m tng dng ca BICC trong vic lin kt hot ng gia mngtruyn thng (PSTN/ISDN) v mng NGN. Hai thu bao in thoi truyn thnglin lc vi nhau thng qua siu khin ca softswitch theo bo hiu BICC.Bo hiu SIP s dng trong trng hp 2 thu bao IP phone hoc mt thu baoIP phone lin lc vi mt thu bao in thoi truyn thng.

3.3.3 Giao thc SIP

SIP (Session Initiation Protocol) l giao thc iu khin lp ng dngc thit k v pht trin bi IETF. Giao thc SIP c s dng khi to,iu chnh v chm dt cc phin lm vic vi mt hay nhiu yu t tham d.Mt phin c hiu l mt tp hp ni gi, ni nhn lin lc vi nhau v trngthi bn trong mi lin lc . V d trng thi c th bao gm cuc gi in

thoi Internet, tn hiu a phng tin phn tn, hi ngh truyn thng aphng tin, hay c th l tr chi my tnh phn tn...

L giao thc bo hiu m, mm do v c kh nng m rng, SIP khaithc ti a cng c Internet to ra nhiu dch v mi trong mng NGN. Sgiao thc bo hiu SIP trong NGN c th hin trong hnh 7. SIP cn cdng lm bo hiu gia 2 SW nh th hin hnh 6.

Giao thc khi to phin SIP thm nhp vo thit k SW khng ch nhmt giao thc bo hiu cuc gi m cn ng vai tr ca mt ccu vn chuyn

cho cc giao thc khc v cho bo hiu ca thit b SW n cc serverng dngv cho cc h thng p ng thoi tng tc hai chiu. Hin nay SIP c dngph bin cho Voice Over IP. Hin nay, SIP ang tr thnh la chn thay thH.323 tr thnh giao thc im ni im (end-to-end protocol) trong cngngh SW.


25/27

Vin i hc mH Ni


Hnh 5: Siu khin MG ca Megaco/H.248

3.3.4 Giao thc H.323

H.323 l giao thc chun cho vic lin lc bng thoi, hnh v d liutrong h thng mng IP (bao gm mng Internet). H.323 l tp hp cc chunca ITU cho vic truyn thng a phng tin v l mt trong nhng chunchnh cho VoIP nh Megaco hay SIP.

H.323 c cng b ln u tin vo nm 1996 v phin bn mi nht(version 5) c hon thnh vo nm 2003. Cc thnh phn trong cu trcH.323 gm c terminal, gateway, gatekeeper... ('Kin trc H.323...' trn TGVTA 1/2004, tr.75).

3.3.5 MGCP: Media Gateway Control Protocol

MGCP l giao thc VoIP v l mt chun c xc nh bi IETF, cdng iu khin MG t MGC/SW. MGCP l mt giao thc ch t(master/slave) m qua MG s thc thi cc lnh c gi t MGC/SW. MGtruyn ti cc loi tn hiu nh thoi, d liu, hnh nh gia mng IP v mngtruyn thng (PSTN). C th hiu, trong m hnh MGCP, cc MG ch trng vochc nng phin dch tn hiu m thanh, trong khi SW m nhn chc nng xl bo hiu v cuc gi.


26/27

Vin i hc mH Ni


Ch , MGCP v Megaco/H.248 u l giao thc iu khin MG tMGC/SW. Tuy nhin, Megaco/H.248 l giao thc mi hn v ang c xu hngthay th MGCP. Mt s thit bc sn xut h trc hai giao thc cng mtlc.

Hnh 7: SIP trong mng NGN

Kt lun

T nhng c im ca mt h thng mng 3G v mng li ca n, ta c

th nhn thy m hnh ph hp vi mng GSM ca Vit Nam hin l m hnh

pht trin dn dn, pht trin 3G t cc thnh ph ri mrng dn ra vng su

vng xa kt hp vi vic nng cp mng li ( NGN ). Tc nhanh hay chm l

ty thuc vo tham vng cng nh nng lc ca tng nh cung cp.

Vic nng cp mng li l rt cn thit cho s hnh thnh v pht trin

ca cc dch v di ng cao cp ngoi dch v thoi truyn thng, gip nng cao

kh nng v dung lng ca h thng. Thm vo , tnh lin mch v k tha

khi nng cp l rt quan trng v tn dng c h thng c sn, khng lng ph


27/27

Vin i hc mH Ni

Tiu lun : Nng cp cng ngh h GMS ln 3G v cu trc mng liGi i h d Ti Ph C H

u t, v nht l bo m s hot ng ca nhiu loi cng ngh trong mt h

thng duy nht. S nng cp lin mch ln 3G ny s gip cc nh khai thc duy

tr c s trung thnh v tha mn nhu cu ngy cng cao ca khch hng,

ng thi gia tng chi v doanh thu cho ngnh vin thng.

Vit Nam, vi xu th pht trin v hi nhp, lnh vc in t - tin hc -

vin thng ang c nhng bc tin nhanh v mnh trong vic ng dng cc

cng ngh mi trn th gii nhm c gng rt ngn khong cch vi cc nc

tin tin.

Documents

Tieu Luan 3G Final