Tong Quan Ve He Thong Mang Gsm 9246

7/29/2019 Tong Quan Ve He Thong Mang Gsm 9246

1/122

ti " TNG QUAN MNG GSM"

___________________________________________________________________________________________________________________________ 1


2/122

MC LC

M U 4

Chng 1 6TNG QUAN MNG GSM 61.1 M HNH KIN TRC CA GSM 61.1.1 Trm di ng MS (Mobile Station) 61.1.2 Modul nhn dng thu bao SIM (Subscriber Identuty Module) 71.1.3 Trm thu pht c s BTS (Base Transceiver Station) 71.1.4 B iu khin trm gc BSC (Base Station controller) 81.1.5 Trung tm chuyn mch cc dch v di ng MSC 81.1.6 B ghi nh v thng tr HLR 81.1.7 B ghi nh v tm tr VLR 81.1.8 B ng k nhn dng thit b EIR 91.1.9 Qun l thu bao v trung tm nhn thc AUC 91.1.10 iu khin qun l v bo dng OMC 91.1.11 Cc giao din trong mng GSM 91.2 M HNH MNG GSM 111.3 MNG TRUY CP GSM 121.3.1 Cc knhvt lLun Vn - n - Tiu Lun Vt L 121.3.2 Cc knh logic 191.4 X L TN HIU S TRONG GSM 221.4.1 M ho ting ni 231.4.2 M ho knh 23

1.4.3 an xen 241.4.4 Mt m ho 261.4.5 iu ch 27Chng 2 30GIAO THC BO HIU MNG GSM 302.1 GIAO THC BO HIU 302.1.1 Giao din A 312.1.2 Giao din Abis 352.1.3 Giao din Air/Um 442.2 TH TC TRONG MNG GSM 572.2.1 Bt tt my trm di ng 57

2.2.2 Gn v tch IMSI 582.2.3 Cp nht v tr 58a. Cp nht v tr trong BSS 58

b. Cp nht v tr trong NSS 622.2.4 Bt u cuc gi 64a. Bt u cuc gi trong BSS 64

b. Bt u cuc gi trong NSS 702.2.5 Cuc gi t u cui di ng 72a. u cui di ng gi trong BSS 72

b. u cui di ng gi trong NSS 78Chng 3 80

CHUYN GIAO MNG GSM 803.1 CC LOI CHUYN GIAO 813.1.1 Trong BTS 81

___________________________________________________________________________________________________________________________ 2
http://www.kilobooks.com/forumdisplay.php?f=173http://www.kilobooks.com/forumdisplay.php?f=173http://www.kilobooks.com/forumdisplay.php?f=173


3/122

3.1.2 Chuyn giao trong cng BSC 813.1.3 Chuyn giao trong cng MSC 823.1.4 Chuyn giao gia cc MSC 823.1.5 Nhn xt 833.2 CC B NH THI 833.3 CHI TIT CHUYN GIAO 87

3.3.1 Trng hp thnh cng 873.3.2 Trng hp tht bi 913.3.3 Quay tr li BSS c 923.3.4 Gii phng cuc gi 933.4 NG DNG SDL PHN TCH CHUYN GIAO 943.4.1 Gii thiu v SDL 943.4.2 Phn tch cc trng hp chuyn giao 953.5 THIT K M HNH 993.5.1 Thit k m hnh tng qut 993.5.2 Cc bn tin 1003.6 M T V M HNH CPN 1033.6.1 Kha cnh ca m hnh 1043.6.2 Cc trang CPN 106KT LUN 118CC THUT NG 119TI LIU THAM KHO 121

LI NI U

S pht trin h tng c s l yu t quan trng thc y nn kinh t phttrin v gp phn nng cao i sng x hi ca con ngi, tha k nhngthnh tu ca cc nghnh cng nghip in t , bn dn , quang hc, tin hcv cng ngh thng tin .... nn cng nghip vin thng trong c thng tindi ng c nhng bc tin nhy vt k diu a x hi loi ngi bcsang mt k nguyn mi : K nguyn thng tin .Tt c chng ta u bit rng, chng ta ang sng trong mt x hi thng tinm trong chng ta phi tip nhn s dng thng tin vi gi tr cao v mtthi gian v cht lng. Sc cnh tranh ca tt c cc ngnh cng nghip bt

ngun t vic to ra cc gi tr ln hn bng cch tn dng cc u th iukin v thi hn. V vy thng tin lin lc s ng vai tr ct li cho vic phttrin tng lai ca x hi thng tin ny, n cng nh lc lng lao ngtrong nng nghip v ngun vn trong cng nghip .

Ngnh cng nghip thng tin lin lc c coi l ngnh cng nghip tr tuhoc l ngnh cng nghip ca tng lai, l nn tng tng cng sc mnhca mt quc gia cng nh cnh tranh trong cng nghip. Ngnh cng nghipny phi c pht trin trc mt bc so vi nhng ngnh cng nghip

khc, bi v s pht trin ca cc ngnh khc da trn c s thng tin lin lc,ngnh m s ch khng n gin phc v nh mt phng tin lin lc m sng vai tr nh mt ngun vn cho x hi tin b.

___________________________________________________________________________________________________________________________ 3


4/122

Di s hng dn, quan tm nhit tnh ca thy gio Phm Minh Vit, em hiu thm c nhiu iu v lnh vc thng tin lin lc cng nh hng

pht trin ca h thng vin thng ti Vit Nam. Do khun kh ca bi vitcng nh cn hn ch v kin thc cho nn khng trnh khi thiu st cngnh lm ln, em mong mun nhn c nhng kin ng gp thm honthin hn na v kin thc ca mnh. Mt ln na, em xin chn thnh cm nthy gip em hon thnh t tt nghip ny.

NI DUNG

PHN I: GII THIU TNG QUAN MNG GSM.

CHNG I: LCH S DCH V THNG TIN DI NG V GII

THIU C TNH, TNH NNG CA MNG THNG TIN DI NG

S GSM.

CHNG II: CU TRC V THNH PHN MNG GSM.

CHG III: CC GII PHP K THUT CHO GIAO TIP V

TUYN.

PHN II: CC CH TIU K THUT CA MNG GSM.

CHNG I: CU HNH TRM GC BTS.

CHNG II: PHNG THC HOT NG V CH TIU K

THUT CA MNG CELLULAR

PHN III: THIT K M PHNG BO HIU S 7

TRONG MNG GSM

___________________________________________________________________________________________________________________________ 4


5/122

___________________________________________________________________________________________________________________________ 5


6/122

PHN I. GII THIU TNG QUAN GSM

CHNG I. LCH S DCH V THNG TIN DI NG V GII

THIU C TNH, TNH NNG CA MNG THNG TIN DI NGS GSM

1.1.LCH S DCH V THNG TIN DI NG:

H thng thng tin di ng t lu l mt khao kht ln lao ca con ngi.

Khao kht ny ch c th tr thnh hin thc ngay sau khi k thut thng tin

bng sng v tuyn in ra i vo th k th 19. Tuy nhin vic a h

thng thng tin di ng vo phc v cng cng ch c thc hin sau chintranh th gii ln th hai.

Do s pht trin ca cng ngh in t v thng tin cng nhu cu i hi ca

con ngi ngy cng tng cao nn mng thng tin di ng ngy cng c

ph bin, tin cy ngy cng tng. Qu trnh pht trin ca mng thng tin

di ng nh sau:

* Th h th nht: Sau nm 1946. Kh nng phc v nh, cht lung khngcao, gi c t.

* Th h th hai: T nm 1970 n 1979. Cng vi s pht trin ca

processor m ca cho vic thc hin mt h thng phc tp hn. Nhng v

vng ph sng ca Anten pht ca trm di ng cn b hn ch do h

thng chia thnh cc trm pht v c th dng nhiu trm thu cho 1 trm

pht.

* Th h th ba: L mng t ong tng t (1979-1990). Cc trm thu

pht c t theo hnh t ong, mi l 2 cell. Mng ny cho php s dng

li tn s, cho php chuyn giao cc vng trong cuc gi.

Cc mng in hnh l:

+ AMPS (Advanced Mobile phone service) : a vo hot ng ti M nm1979.


7/122

+ NMT (Nordic Mobile Telephone System) : L h thng in thoi di ng

tng t ca cc nc Bc u (1981).

+ TACS (Total Access Communication System) : nhn c t AMPS

c lp t Anh nm 1985.

Ngy nay hu ht tt c cc nc Chu u u c 1 hoc nhiu mng t ong.

Tt c nhng h thng t bo ny u thc hin vic truyn m tng t bng

iu tn. H thng dng bng tn xung quanh tn s 450MHz hoc

900MHz, vng ph sng thng l vng rng vi s lng thu bao ln n

hng trm ngn.

- Th h th t: L th h da trn k thut truyn dn s.

+ GSM (Global System for Mobile Communications) : a vo hot ng ti

Chu u t nm 1992.

+ DCS (Digital Cellular System) : Da trn mng GSM s dng tn s

1800MHz.

+ CDMA(Code Division Multi Access) : Trong tng lai.

Bng 1. Gii thiu mt s mng t ong tng t c vn hnh chu

u

___________________________________________________________________________________________________________________________ 7


8/122

Nc H thng Bng tnThi im

vn hnh

S thu bao

(ngn thu

bao)

AnhBc u

TACSNMT

450900

19811985

12001300

Php

NMT

Radio

Com200

450

450-900

1989

1985

90

300

ItaliaRTMS

TACS

450

900

1985

1990

60

560

c C450 450 1985 600Thu in NMT 900 1987 180

H Lan NMT450

900

1985

1989130

oNMT

TACS

450

900

1984

1990

60

60Ty Ban

Nha

NMT

TACS

450

900

1982

1990

60

60

1.2 MNG THNG TIN DI NG GSM:

T u nm 1980 sau khi h thng WMT c a vo hot ng mt

cch thnh cng th n cng biu hin mt s hn ch:

Th nht: Do yu cu dch v di ng qu ln so vi con s mong i ca

cc nh thit k h thng, do h thng ny khng p ng c.

Th hai: Cc h thng khc nhau ang hot ng khng ph hp vi

ngi dng trong mng.

V d: Mt u cui trong TACS khng th truy nhp vo mng NMT cng

nh mt u cui di ng NMT cng khng th truy nhp vo mng TACS.

Th ba: Nu thit k mt mng ln cho ton Chu u th khng mt nc

no p ng c v vn u t ln.

___________________________________________________________________________________________________________________________ 8


9/122

Tt c nhng iu dn n mt yu cu l phi thit k mt h thng mi

c lm theo kiu chung c th p ng c cho nhiu noc trn th

gii. Trc tnh hnh vo thng 9/1987 trong Hi ngh ca Chu u v

bu chnh vin thng, 17 quc gia ang s dng mng in thoi di ng hp hi ngh v k vo bin bn ghi nh lm nn tng cho mng thng tin di

ng s ton Chu u.

n nm 1988 Vin tiu chun vin thng Chu u (European-

Telecommunication-Standard Institute) thnh lp nhmc trch v mng

thng tin di ng s GSM. Nhm ny c nhim v a ra tiu chun thng

nht cho h thng thng tin di ng s GSM di hnh thc cc khuyn ngh,ly cc tiu chun ny lm c s cho vic xy dng mng thng tin di ng

v lm sao cho chng thng nht, tng thch vi nhau.

*V mt k thut:

Mt s mc ch ca H thng sng t mt trong nhngmc ch y l h

thng cn cho php chuyn vng t do vi cc thu bao trong Chu u, c

ngha l thu bao ca nc ny c th thm nhp vo mng ca noc khc

khi di chuyn qua bin gii trm GSM-MS (Mobile -Station) phi to cho

ngi dng gi hoc b gi c trong vng ph sng quc t.

* Cc ch tiu phc v:

- H thng c thit k sao cho MS c th c dng trong tt c cc nc

c mng.

- Cng vi phc v thoi, h thng phi cho php s linh hot ln nht cho

cc loi dch v khc lin quan n mng lin kt s liu a dch v ISDN

(Intergrated Service Digital Network).

- To mt thng c th phc v cho cc MS trn cc tu vin dng cng nh

mt mng m rng ca cc dch v di ng mt t.

* V cht lng phc v v an ton bo mt:

___________________________________________________________________________________________________________________________ 9


10/122

- Cht lng ca ting thoi trong GSM phi t nht c cht lng nh

cc h thng di ng tng t trc trong iu kin thc t.

- H thng c kh nng mt m ho thng tin ngi dng m khng

nh hng g n h thng, cng nh khng nh hng n thu bao khckhng dng n kh nng ny.

* V s dng tn s:

- H thng cho php kh nng s dng di tn t hiu qu cao c

th phc v vng thnh th ln vng nng thn cng nh cc dch v mi

pht trin.

- Di tn s hot ng: 890-960MHz.

- H thng GSM900 phi c th cng tn ti vi cc h thng dng 900MHz

trc y.

* V mng:

- K hoch nhn dng da trn khuyn ngh ca CCITT. K hoch nh scng da trn khuyn ngh ca CCITT. H thng phi cho php cu trc v t

l tnh cc khc nhau khi dng trong cc mng khc nhau.

- Trung tm chuyn mch v cc thanh ghi dch v phi dng h thng bo

hiu c tiu chun ho quc t.

1.3 CC C TNH V PHC V CA GSM:

1.3.1 Cc c tnh ca mng thng tin di ng s GSM:

T cc khuyn ngh ca GSM ta c th tng hp nn cc cc c tnh ch yu

sau:

- S lng ln cc dch v v tin ch cho cc thu bao c trong thng

tin thoi v s liu.

- S tng thch ca cc dch v trong GSM vi cc dch v ca mng c sn

(PSTN-ISDN) bi cc giao din theo tiu chun chung.

___________________________________________________________________________________________________________________________ 10


11/122

- T ng cp nht v tr cho mi thu bao di ng.

- linh hot cao nh s dng cc u cui thng tin di ng khc nhau nh

my xch tay, my cm tay, t trn t.

- S dng bng tn s 900MHz vi hiu qu cao nh s kt hp gia TDMA

(Time Division Multiple Access) vi FDMA (Frequency Division Multiple

Access).

- Gii quyt s hn ch dung lng nh vic s dng tn s tt hn.

* Cc dch v c tiu chun GSM:

Cc dch v thoi:

- Chuyn hng cc cuc gi v iu kin.

- Chuyn hng cuc gi khi thu bao di ng khng bn.

- Chuyn hng cuc gi khi thu bao di ng bn.

- Chuyn hng cuc gi khi khng n c MS.

- Chuyn hng cuc gi khi nghn v tuyn.

- Cm tt c cc cuc gi ra.

- Cm tt c cc cuc gi ra quc t.

- Cm tt c cc cuc gi ra quc t tr cc nc PLMN thng tr.

- Cm tt c cc cuc gi n.

- Cm tt c cc cuc gi n khi lu ng ngoi nc c PLMN thng

tr.

- Gi cuc gi.

- i gi.

- Chuyn tip cuc gi.

- Hon thnh cc cuc gi n cc thu bao bn.

___________________________________________________________________________________________________________________________ 11


12/122

- Nhm v s dng khp kn.

-Dch v ba pha.

- Thng bo cc ph.

-Dch v in thoi khng tr cc.

- Nhn dng s ch gi.

- Nhn dng s thoi c ni.

- Nhn dng cuc gi him th.

- Cc dch v s liu:

- Truyn dn s liu

- Dch v bn tin ngn

- Dch v hp th thoi

- Pht qung b trong cell.

1.4 H THNG T ONG (GSM CELLULAR SYSTEM):

Mng thng tin di ng l mng khng dy, cc thu bao l di ng do c

hai vn c t ra l:

- Qun l di ng (MM: Mobile Management).

- Qun l tim nng v tuyn (RM: Radio Management).

Vic qun l di ng c t chc theo mng PLMN (Public Land Mobile

Network), mng di ng cng cng mt t. PLMN c coi l mt phn

mng c nh c nh tuyn cuc gi. PLMN c chia thnh nhiu

v tuyn nh c bn knh t 350m cho n 35km. Kch thc trn da vo

a hnh v lu lng thng tin. Mi v tuyn tng ng vi mt trm thu

pht c s (BTS: Base Tranceiver Station) tu theo cu to ca anten. C hai

loi BTS:

___________________________________________________________________________________________________________________________ 12


13/122

* BTS Onnidirectional vi anten v hng, c bc x ngoi khng gian c

gc nh hng l 3600.

* BTS Sector vi 2 hoc 3 anten nh hng 1800 hay 1200, cc v tuyn

ny c sp xp dng t ong (Hnh v 1) v n da vo cc yu t sau:

Trong thc t, do s tng trng lu lng khng ngng trong mt cell no

n mc cht lng phc v gim st qu mc ngi ta phi thc hin

vic chia tch cell thnh cc cell nh hn. Vi chng, ngi ta dng cng

sut pht nh hn v mu s dng li tn s c s dng t l xch nhhn( hnh sau minh ho iu ny

___________________________________________________________________________________________________________________________

2

1

1TCSM23

2

3

1

1

2

3

Hnh v 1

East to wost (50) ofmotropolitanarea

13


14/122

Thng thng cc cuc gi, c th khng xong trong mt cell. Vy h thng

thng tin di ng cellular phi c kh nng iu khin v chuyn mch

chuyn giao cuc gi t cell ny sang cell khc m cuc gi c chuyngiao khng b nh hng g. Yu cu ni trn lm cho mng di ng c cu

trc khc bit vi cc mng c nh .

___________________________________________________________________________________________________________________________ 14


15/122

CHNG II: CU TRC V THNH PHN MNG GSM

2.1 CU TRC MNG GSM:

Cc k hiu :

SS: H thng chuyn mch

AUC: Trung tm nhn thc

VLR: B ghi nh v tm tr

HLR: B ghi nh v thng tr

EIR: Thanh ghi nhn dng thit b

MSC:Trung tm chuyn mch cc dch v di ng( gi tt l tng i

v tuyn)

BSS: H thng trm gc

BTS: Trm thu pht gc

BSC: H thng iu khin trm gc

MS: Trm di ng

OMC: Trung tm khai thc v bo dngISDN: Mng lin kt a dch v

___________________________________________________________________________________________________________________________

AUC

MSC

HLRVLR EIR

IDN

PSPDN

PSTN

PLMN

CSPDN

BSC

BTS

MS

OSS

BSS

SS

15


16/122

PSPDN: Mng chuyn mch cng cng theo gi

PSTN: Mng chuyn mch in thoi cng cng

PLMN: Mng di ng cng cng mt t .

Cu trc mng di ng s GMS theo khuyn ngh ca GMS. Mng GMS

c chia thnh h thng chuyn mch (SS) v h thng trm gc (BSS). Mi

mt h thng cha mt s khi chc nng v cc khi ny c thc hin

cc phn cng khc nhau.

2.2 CU TRC MNG A L :

y l mt yu t quan trng i vi mt mng di ng bi tnh lu ng ca

thu bao trong mng.

2.2.1. Tng i v tuyn cng (GATEWAY-MSC)

GMSC lm vic nh mt tng i trung kvo cho mng GSM/ PLMN. N

thc hin chc nng hi nh tuyn cuc gi cho cc cuc gi kt cui di

ng, cho php h thng nh tuyn cc cuc gi n ni nhn cui cng cachng l cc trm di ng b gi.

Tt c cc cuc gi vo GSM/PLMN s c nh tuyn n mt hay nhiu

GMSC.

2.2.2. Vng phc v MSCNNF:

Vng MSC c mt MSC qun l. V nh tuyn cuc gi n mt thu

bao di ng, ng truyn qua mng s ni n MSC vng phc v m

thu bao ang . Vng phc v l b phn ca mng c nh ngha nh

___________________________________________________________________________________________________________________________

X

X

X

PTSN PTSN

ISND

GMSC

16


17/122

mt vng m c th t n mt trm di ng nh vic trm ny c

ngh li mt b nh v tm tr VLR. CME 20 vng MSC v vng phc

v bao ph cng mt b phn ca mng.

* Vng nh v (Location Area):

Mi vng phc v MSC/VLR chia thnh nhiu vng nh v . Ti y MS c

th t do di chuyn khng cn cp nht thng tin v v tr cho tng i

MSV/VLR iu khin vng ny, khi mt thng bo tm gi s c pht

qung b tm thu bao di ng b gi. Vng nh v c th c mt s v

ph thuc vo mt hay nhiu BSC nhng ch mt MSC/VLR. Vng c

nhn dng bi h thng LAI (nhn dng LAI v oc h thng s dng tm

mt thu bao ang trng thi hot ng).

* 8 (cell):

8 thuc vng nh v v l mt vng bao ph v tuyn c nhn dng ton

cu (CGI).

Trm di ng t ng nhn dng mt 8 bng cch s dng nhn dng trmgc (BSIC).

2.3. CC THNH PHN MNG GMS:

Ngoi hai h thng chnh SS(Switching System) v BSS (Base Station

System) c mng in thoi chuyn mch cng cng PSTN c ni mng

thng tin di ng mt t cng cng PLMN qua SS v trm di ng MS

thuc thu bao.

2.3.1. H thng chuyn mch (SS) :

H thng chuyn mch SS ca CME 20 da trn c s cng ngh AXE cho

php t mc linh hot cao, gi thnh h nh cu trc Mobile AXE. SS

cua CME20 h tr cc giao tip ng dng ca tiu chun GSM.

*Khi chc nng ca SS:

___________________________________________________________________________________________________________________________ 17


18/122

- Trung tm chuyn mch cc nghip v di ng cng (GMSC).

- Trung tm chuyn mch cc dch v di ng (MSC).

- B ghi nh v tm tr (VLR)

- B ghi nh v thng tr (HLR)

- Trung tm nhn thc (AMC)

- B ghi nhn dng thit b (EIR)

*c tnh v nhim v ca tng khi:

- MSC: l ht nhn ca mng PLMN, n c nhim v nh tuyn v kt nicc phn t ca mng thu bao di ng vi nhau hoc vi thu bao ca mng

PSTN v ISDN. Cc s liu lin quan n thu bao di ng c cung cp t

HLR, VNR, AUC v EIR, t cc bo hiu cn thit s c pht ra cc

giao din ngoi vi vi tt c cc thnh phn mng (BSS/HLR/AVC/EIR/OMC)

v ni vi mng c nh PSTN hay ISDN. MSC cncung cp cc dch v ca

mng cho thu bao. N cha cc d liu v thc hin qu trnh Hardover.Trong ch thoi mt b phn Echo-Canceller c t gia MSC v

PSTN trit ting vng gy ra cc b bin i t 2 dy sang 4 dy trong

PSTN.

- HLR: C s d liu quan trng nht ca mng di ng s. HLR c s

dng theo di MS, l ni thu bao mua mt ng k t mt hng khai thc

GMS m HLR thuc hng ny. HLR cha thng tin v thu bao nh cc dchv b xung v cc thng s nhn thc. N cha thng tin v v tr thng tin

ca MS trong mt vng MSC no v thng tin ny thay i th MS di

ng. MS s gi i thng tin v v tr (qua MSC/VLR) n HLR ca mnh

nhm m bo phng tin thu mt cuc gi. Trong HLR cn thc hin to

mt bo hiu s 7 trn giao din vi MSC.

- VLR: L c s d liu cha thng tin v tt c cc MS hin vng phc vca MSC. Mi MSC c mt VLR v VLR c kt hp trong phn cng ca

___________________________________________________________________________________________________________________________ 18


19/122

MSC. VLR c th coi nh mt HLR phn b. VLR cha thng tin chnh xc

hn v v tr ca MS vng MSC. Trong trng hp MS lu ng v cng

MSC mi. VLR lin kt vi MSC ly s liu v MS ny t HLR v thng

bo cho HLR v tr ca MS sau VLR c th thit lp cuc gi cho MS mkhng cn n HLR.

- AUC: L mt b phn trong phn cng ca HLR trong GSM c nhiu

bin php an ton khc nhau trnh vic s dng tri php, cho php bm

v ghi li cuc gi ng v tuyn. Vi mi mt m thu bao c mt m bo

mt ring bit nhm chng li s nghe trm, m ny c bo v chng mi

xm nhp tri php.

- EIR: Cha s liu phn cng ca thit b (MS). EIR c ni vi MSC qua

ng bo hiu, cho php MSC kim tra s hp l ca thit b. N bo v

mng PLMN khi s thm nhp ca thu bao tri php.

- OSS: H thng khai thc h tr c ni n tt c cc thit b h thng

chuyn mch v ni n BSS. OSS c cc chc nng sau:

+ Qun l h thng chuyn mch, quy nh cc thay i s thoi, phn tch

tuyn, cc bng phn tch IMSI,...

+ Qun l thu bao : Cc loi u ni, gii phng ni, cc nhn dng nh v

vng (LAI).

+ Qun l TRX: Cc qui nh TRX, TRI, cc knh lgc,...

+ Cc chc nng o : Lu lng cc chuyn giao thng k,...

*H thng trm gc:

___________________________________________________________________________________________________________________________ 19


20/122

- Cu hnh h thng:

BSS chu trch nhim ch yu cc chc nng v tuyn h thng qun l

thng tin v tuyn vi cc my di ng. N cng iu khin vic chuyn giao

cc cuc gi an tin hnh gia cc c iu khin bi BSC ny. BSS

chu trch nhim qun l tt c cc tim nng v tuyn ca mng v s liu

v cu hnh ca . CME 20 BSS c th thc hin cc hnh ng ph hp

khi xy ra cc tnh hung khng bnh thng mc d khng t ti OSS. BSScng iu khin cc mc cng sut v tuyn cc trm gc cng nh trm di

ng.

BSS cha mt b iu khin trm gc BSC (Base Station Controller) v mt

hay nhiu trm thu pht gc BTS (Base Tranceiver Station).

Nu khong cch gia BTS v BSC nh hn 10m cc knh thng tin c th

ni trc tip (Combine), nu ln hn th c th phi qua mt giao din ABIS(Remote). Mt BSC c th qun l nhiu BTS theo cu hnh hn hp theo

kiu trn.

2.4 CHC NNG CA BSC V BTS:

2.4.1 Chc nng ca BTS :

Mi trm BTS phc v cho mt cung cp ng truyn v tuyn. BTSc gii hn bi hai giao din:

___________________________________________________________________________________________________________________________

RBS200

RBS200

RBS200

BSC AXE10

Giao tipA

Giao tipA

RBS Trm gc vtuyn

SS

20


21/122

- Giao din v tuyn (gia BTS v MS).

- Giao din BTS - MSC, giao din ny c thc hin cc dng:

+ Giao din Abis khi BTS t cch xa GSC trn 10 m (cu hnh t xa).

+ Giao din ni b c gi l giao din trm gc ( BSI) khi BTS v BSC t

cch xa nhau di 10m ( cu hnh kt hp v khi khng cn giao din Abis v

l do khc nhau).

BTS m bo:

+ ng ni v tuyn vi MS.

+ Phn bng c s ca lp thu pht 1 v 2. Phn ny s l giao thc thm

nhp ng truyn knh D (LAPD: Link Access Procotol on D channel )

gia BTS v BSC v giao thc thm nhp ng truyn knh D di ng

(LAPDm Link Acces Procotol on D mobile) gia BTS v MS. LAPDm c

th c s dng ng thi cho bn tin ngn.

+ Cc chc nng khai thc v bo dng ring cng vi chc nng qun lcc tim nng v tuyn.

* Cc tnh nng ca mt trm BTS:

- nhy my thu: ln hn hoc bng -140 dBm.

- B tr tr a tia: S cn bng cho php b tr tr a tia n 20 s.

- Nhy tn:cho php s dng thm b thu pht phc v cho nhy tn.

- Anten: BTS c th u ni n mt anten pht v mt hoc hai anten thu

( trng hp phn tp khng gian). Anten c th v hng mt phng

ngang (Omnidirectiontal) hay nh hng hnh qut 1200 (Sectorial Anten ).

- Cng sut pht: Cng sut pht trc khi ghp chung vo anten l 26W hay

69W (hay 30W). C th iu chnh cng sut pht tng nc 2dB.

* Chc nng chung ca BSC:

___________________________________________________________________________________________________________________________ 21


22/122

BSC thc hin cc chc nng qun l tim nng v tuyn. Cc chc ng

chnh ca BSC l:

- Thit lp v gii phng cc tim nng v tuyn theo nhu cu ca MS v

MSC.

- Chuyn giao MS.

- iu khin cng sut BTS v MS c th thc hin bi BTS hoch bi BSC.

Nh khai thc c th t trung tm khai thc v bo dng (OMC) np phn

mm mi v d liu xung BSC , thc mt s chc nng khai thc v bo

dng: hin thi cu hnh BSC.

BSC cng c th thu nhp cc s liu o t BTS, BIE, lu gi chng trong b

nh v cung cp OMC theo yu cu. Gioa din gia BSC v OMC c thc

hin bng cc ng truyn X.25. BSC cng c giao din ngi my u ni

ti ch thit b my tnh u cui.

Giao din A gia BSC v MSC s dng bo hiu knh chung s 7, cn giao

din Abis gia BSC v BTS s dng LAPD.

ng truyn vt l ni gia BSC vi BTS v MSC l cc ng 2M G

703, mt s h thng khi TRAU t MSC. Gia MSC v BTS cc my

ghp knh ph c s dng tit kim ng truyn. cc h thng c

TRAU t ti BSC th cc knh lu lng n MSC l 64 Kbis/s.

___________________________________________________________________________________________________________________________ 22


23/122

___________________________________________________________________________________________________________________________ 23


24/122

CHNG III. CC GII PHP K THUT CHO GIAO TIP V

TUYN

3.1 V TUYN S TNG QUT:

chng ny cp n vic s dng thit b v tuyn truyn thng tin

gia trm di ng v mng PLMN GMS m khng dng n y trong mng

t ong m n nh hng n cc tn hiu thu. Mt s vn quan trng khi

quy hoch tn s l s hn ch bi i lng nhiu ca h thng t ong.

3.1.1. Suy hao ng truyn v pha inh:

Suy hao ng truyn l qu trnh m tn hiu thu yu dn o khongcch gia trm di ng v trm gc tng m khng c mt cn gia.

Ls d2.f2

Ls (dB) = 33,4 (dB) + 20logF(MHz) + 20log(km)

Tx v Rx: Vi khng gian t do , suy hao ng truyn c tnh:

d: l khong cch gia anten pht Tx v thu Rx.

f: tn s pht

(Cng thc trn ch ng vi cc h thng v tuyn di ng gn BS.)

Mi trng s dng ca MS ca thng c chong ngi vt gy hiu ng che

ti lm gim cng che tn hiu. Khi di ng cng vi i di ng cng

tn hiu gim , tng d gia TX v RX c hay khng c chng ngi.

Hiu ng ny gi l pha inh chun lgc. Thi gian gia 2 ch trng pha

inh khong v khong v gy ra vi MS lp trn xe v chuyn ng.

___________________________________________________________________________________________________________________________

MS

24


25/122

Trong trng hp mi trng thng tin c mt thu bao dy v nhiuchng ngi ta c pha inh nhiu tia hay raile, xy ra khi tn hiu nhiu

ng t anten Tx n Rx.

hin tng pha inh raile, tn hiu thu c l tng cc tn hiu phn x

khc fa, khc bin . Nhng tn hiu ny khi cng li nh cc vct to nn

mt vct tng gn bng khng c nghi l cng tn hiu bng 0. y l

ch trng pha nghim trng.

mt khong cch nht nh Xm so vi Tx, tn hiu thu c minh ho nh

sau:

nhy my thu l mc tn hiu vo yu nht cn thit cho mt tn hiu ra

qui nh. Khi quy hoch h thng, chng li pha inh th gi trih trung

bnh chung c ly ln hn nhy my thu lng Y(dB) bng ch trng

pha phainh mnh nht, Y(dB) c gi l d tr phainh.

3.1.2. Phn tn thi gian:

Hin tng ny c ngun gc t phn x t mt vt xa anten th Rx v km.

N dn n giao thoa gia cc k hiu ISI tc l giao thoa gia cc k hiu

ln cn vi nhau.

___________________________________________________________________________________________________________________________

Dtrpadinh

Gi tr trung bnhcc b

Ch trngpadinh

Cng tn hiu thu (Rx) Fc =900MHz

nhy mythu

mX +15

X +10X

Gi tr trung bnhchung

25


26/122

GMS tc bit l 270kB/s, mi bit tng ng vi 3,7s v tng ng vi

khong cch l 1,1km. Khi c phn x t 1km pha sau trm di ng th tn

hiu phn x phi qua gng ng di tr tn hiu i thng 2km. Tn hiu

mong mun s c trn vi tn hiu 2bit.

3.1.3. Cc phng php phng nga suy hao truyn dn do phainh:

ci thin my thu v cht lng ca tn hiu thu, c 4 phng n thc

hin nh sau:

*Phn tp anten:

trnh nguy c c 2 anten thu b ch trng phainh su cng mt lc, ta s

dng 2 anten Rx c lp thu cng tn hiu ri kt hp cc tn hiu ny li ta

s c mt tn hiu ra khi b kt hp t b phainh hn. Khong cch gia 2Tx v 2Rx phi ln khng gian tn hiu 2 anten nh.

___________________________________________________________________________________________________________________________

21

Tn hiu1

Tn hiu2CTH

SSAnten

BTS

0

0

1

1

Giao thoa k hiu (1) v (0)

26


27/122

*Nhy tn:

Vi pha inh raile, mu phainh ph thuc vo tn s ngha l ch trng

phainh xy ra cc v tr khc nhau i vi cc tn s khc nhau. Nh vy

ta c th thay i tn s sng mang trong mt s tn s khi cuc gi ang tinhnh, khi gp ch trng phainh ch mt phn thng tin b mt. khi phc

li thng tin hon thin ta dng phng php sau:

*M ho knh:

truyn dn s ngi ta o cht lng ca tn hiu c ch yu bng s

lng cc bit thu c chnh xc, u n biu din t s bit li BER. BER

khng th bng khng do thay i ng truyn nu c c cho php mt

lng nht nh v c kh nng khi phc thng tin ny hoc c th pht hin

trnh s dng thng tin li. BER quan trng vi pht s liu hn Voice.

phng php m ho knh ta phi pht i mt lng thng tin c s bit ln

hn nhng s t an ton chng li cao hn. M ho knh c th pht hin

v sa li tng bit thu.V d: Khi mun gi mt bit 0 hay 1 c bo v ta b xung thm bao

bit nh sau:

Thng tin

0

1

B xung

000

111

Gi i

0000

1111

Khi m 0000 s ng vi 0 v 1111 s ng vi 1. T l l 1:4V, bo v sxy ra nh sau:

Thu c : 0000 0010 0110 0111 1110

Quyt nh: 0 0 x 1 1

Ring cm 0110 khng xc nh c c th, trm 0111 v 1110 c pht

hin l li.

___________________________________________________________________________________________________________________________ 27


28/122

Mi knh kim tra li cchia thnh mi khi v m xon. m khi, mt

s bit kim tra c b xung vo mt s bit thng tin nht nh. Cc bit kim

tra ch ph thuc vo cc bit thng tin khi bn tin.

m ho xon, b m ho to ra khi cc bit m khng ch ph thuc vocc bit ca khi bn tin hin thi c dch vo b m ho m cn ph thuc

vo cc bit ca khi trc.

M ho khi thng c s dng khi c bo hiu nh hng theo khi v

s dng pht hin li khi thc hin Yu cu t ng pht ARQ.

M ho xon lin quan nhiu hn n s sai li. C hai m ny c s dng

GSM. Hai bc m ho c dng cho c ting v s liu.

* Ghp xen:

Cc li bit thng xy ra theo tng cm o cc ch trng phainh ln lm

nh hng nhiu bit lin tip. gii quyt hin tng li bit qu di ta dng

phng php ghp knh xen tch cc bit lin tip ca mt bn tin sao cho

cc bit ny gi i khng lin tip.

Khi truyn dn khung 2 c th mt nu khng ghp xen ton v khi bn tin

s mt nhng ghp xen s m bo ch th th hai tng khi l b mc li:

1 x 3 4 1 x 3 4 1 x 3 4 1 x 3 4

M ho knh c th khi phc li thng tin ca tt c cc khi. GMS b m

ho knh cung cp 456bit cho tng 20Ms ting v oc ghp xen to ra

cc khi 57bit.

___________________________________________________________________________________________________________________________

1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4

Cc khi bntin ghp xen

Cc khi bntin cghp xen

Mt khung

28


29/122


30/122

Xt nguyn l lm vic ca mt b cn bng: Sau khi lp m hnh knh ta s

phi to ra tt c cc chui bit c th c ri a chng qua m hnh knh

chui u vo m t nhn c chui u ra ging n nht gi l chuinguyn thu hay chui pht. Theo quy nh ca GMS, mt b cn bng cn

c kh nng x l mt tn hiu phn x tr n 14,8s tng ngvi thi gian

ca 4bit. Lc ny ngay c tn hiu phn x cng b nh hng bi phainh

raile, nhng do tn hiu ny c mu phainh c lp so vi tn hiu i thng

nn n c li dng t hiu qu cao hn. Vy vi cc tn hiu phn x

tr di 15Z n cho ta thm nng lng ci to tn hiu thu.

Trn thc t di chui N thng ln ln phi c thc hin nhiu so snh

v mt nhiu thi gian tnh ton gy mt s chm tr khng cho php.

khc phc kh khn ny ngi ta phi s dng n thut ton Vinri m

khng cn phi th tt c cc chui.

3.1.5. Truyn dn s v tn hiu tng t:

Trong trng hp truyn ting ni l dng sng lin tc khc vi truyn s

liu ta phi thc hin ly mu tn hiu tng t, lng t m ho tn hiu

dng s 1 v 0. Cc mu tng t c trnh by bng mt tp hp hu

hn cc mc c xc nh bi s cc bit ta cn s dng trnh by mt

mu.

h thng vin thng s chn s mc ri rc ho =256 mc (8bit) vi mi

mu ta trnh by gi tr tng t bng mt gi tr c lng t ho 8bit.

Vi tc ly mu 8kHz ta c tc bit:

8000mu/s x 8bit = 64kb/s

Qu trnh ny c gi l iu ch xung m PCM gm 3 bc:

___________________________________________________________________________________________________________________________

Lngt

Ly mu M hong truynPCM 64 kb/s

30


31/122

Ta t nhiu knh trn cng mt ng truyn PCM (ghp knh) trnh

lng ph. Nu ghp 32 knh trn mt ng truyn PCM theo tc bit ca

n l : 32x64kb/s=2,048Mb/s. Thit b ghp knh iu khin vic gn cc khethi gian 0,1 gi i khe 1,...Trong 32 knh truyn th knh 0 dng cho ng

b, knh 16 dng cho bo hiu cn 30 knh cn li dng cho ting thoi.

Phn trnh by trn l v d v a thm nhp phn chia theo thi gian TDMA.

Mt phng php khc vi TDMA v FDMA (a thm nhp phn chia tn

s) c dng qung b v tuyn, mi knh c dnh cho mt bng tn

ring. Tng ng h thng di ng t ong tng t, mi cuc gi mt s dng mt bng tn (hai bng khi truyn song cng). Sau y l so snh

gia TDMA v FDMA

*ng b thi gian: Khi s dng TDMA v tuyn, mi trm di ng s

dng khe thi gian Ts ca mnh nhng khi khong cch gia MS v BS tng

ln gy tr thi gian truyn tn hiu v tr ny ln qu th thng tin pht i t

MS khe TS n s trng vi tn hiu thu c ca BS ti khe TS n+1 ca MS

khc. kim tra thi gian n v cc lnh oc gi n MS ta c qu trnh

nh trc thi gian mi khi MS di chuyn ra xa.

*M ho ting: mt s h thng di ng t ong FDMA khong cch gia

cc knh l 25kHz (NMT, TACS) v GMS khong cch ny bng 200kHz.

So snh TDMA 200kHz v FDMA 25kHz ta c hiu qu s dng tn s nh

nhau v knh 25kHz c tc 412kB/s. Khi s dng phng php iu chpha ti thiu Gauss (GMSK) rng bng khng b chiu s rt ln. m

___________________________________________________________________________________________________________________________

0 1 2 3 4 5 6 7MS

1

MS2

MS2

MS5

TDMA

31


32/122

bo bng tn cho php ta gim ti thiu tc bit cho tng knh ting bng

cch m ho ting (Vocodes) v m ho theo dng sng.

M ho theo kiu pht m Vocodes gip ta nhn bit c ting ni nhng

rt tng hp v ta kh nhn ra ai pht m.S dng m ho sng (m ho PCM ng u) thng tin trc tip chnh thc

dng sng c pht i vi tc i hi cao v cho ta mt cht lng cng

rt cao. Tc bit b m ho dng sng thay i gn t 16kb/s n 64kb/s

i vi b m ho PCM ng u.

Ngoi ra ta cn c cc b m ho cho php c m t nh mt s pha trn

gia Vocodes v m ho dng sng. Cc b m ho lai ghp lp kn ch trng

gia cc b m ho Vecodes v dng sng vi tc bit t 5kb/s, cht lng

theo tc bit. GMS s dng b m ho ghp lai gi l m ho tin nh

tuyn tnh-Tin nh thi gian di-kch thch xung u. B LPC-LPT-RPE.

- LPC v cc thng s LPD: 3,6kb/s.

- Cc thng s RPE: 9,4kb/s- Tc bit u ra b m ho ny l 13kb/s, 20ms ting cho 260bit.

3.1.6: B chuyn i m v ghp knh TCSM(Trans Code and Subrate

Channel Multiplexer).

Tng quan v TCSM.

Chc nng chuyn i m v ghp knhTCSM l mt phn modul ca phn

h trm gc BSS.

Mc ch ca TCSM l:

- Cung cp s chuyn i gia cc dng tn hiu trn ng truyn 16Kbit/s

64Kbit/s trong mng di ng GSM.

___________________________________________________________________________________________________________________________ 32


33/122

- Gim s knh truyn dn trn mt t phc v cho u i gia trm gc v

trung tm chuyn mch di ngMSC.

Vic gim s knh t c bng cch t thm chc nng chuyn i m

ti MSC v BSC, s dng cc knh 16Kbit/s cho truyn thoi v truyn s

liu. Ghp 90knh 16Kbit/s trn mt ng truyn 2048Kbit/s thnh 90 knh

cao tc.

V tr thun li cho b chuyn i m TC l t ti v tr MSC. V rng trong

trng hp cc knh 16Kbit/sc s dng trn tt c ng truyn, gia

BSC v MSC v s ghp knh cng c th c s dng tip kim ng

truyn. Hn na, chuy mch iu khin gc BSCcho php s dng tt nht

b chuyn i m.

Trong thc t:

- B chuyn i m c th c trang b theo s cc knh c s dng gia

BC v MSC. Ni chung, s b chuyn i th t hn s knh Traffic trn giao

din BSS.

- Li ca b chuyn i m khng nh hng lm n .

- S linh hot ca b chuyn i m cho php thay bng cc loi mi trong

tng lai. (Hnh sau ch ra nguyn l truyn dn chug gia BSC v MSC ).

___________________________________________________________________________________________________________________________

TCSM TCSM MSCBSC

33


34/122

Hnh sau ch ra thit b c s dng trong ghp knh ng truyn

2048Mbit/s:

B chuyn i m TC c th c s dng mt cch c lp m khng cn

thit b ghp knh. V d trong trng hp TC c th c t gia MSC v

BSC hoc ti v tr MSC hoc ti v tr BSC.

iu ny cho php d dng s dng TC c th c hoc khng cSM. Trong

trng hp c bit tai MSC hoc BSC. B SM c th c s dng gia

BSC v TC nhng khng c gia MSC v TC.

B TCSM gm 2 phn chnh m c th c s dng mt cch c lp l:

- B chuy i m TC(TransCoder).

- B ghp knh SM( SubMultiplexer).

*B chuyn i m TRCU(transCoder Unit).

cho php s dng mt cch linh hot TC bao gm mt nhm cc

modulc lp m c th c t giao din BSC/MSC, hoc MSC, hoc BSC.

___________________________________________________________________________________________________________________________

BSC TR MSC

BSC TR MSC

TC

TC

BSC MSCTR SMSM TC

34


35/122

B TRCU thc hin s chuyn i m cho knh thoi, c th ln ti 30 knh.

N c giao din 2Mbit/s( A_interface) vi MSC, mt giao din 2Mbit/svi

BSC( hoc SM) ni m cc knh 16Kbit/s c ghp thnh knh 64Kbit/s.

Trn giao din A_interfacecuae TRCU cc knh c m ho v c tchc theo chun ng truyn, theo khuyn ngh G732. Trn giao din vi

BSC ca TRCU, cc knh thoi s liu c chuyn dn tng 2 bit mt bi

cc bit 1 v 2 ca khe thi gian 8 bit.

Mt modul TRCU y d gm 30TRAU ( An individual TransCoder Unit).

M 29 hoc 30 b ny c th c s dng cho chuy i m cho cc knh

traffic. Mt b TRAU tng ng vi 32 khe thi gian ca ng truyn s2048Kbit/s. TS0 lun lun khng c truy nhp, TS1.... TS15 v TS17....

TS31 thng mang Traffic, v TRCU c th qun l chng. TS31 cng c

th c s dng truyn LAPD hoc knh Q1.

Nu SM khng c s dng, mt TS phi c dnh cho tn hiu gim

st,Q1 v TRAU tng ng vi TS ny khng c s dng.

Nu b iu khin TC, TSC ti v tr TS, mt TS trn trung k A phi c

dnh cho LAPD t BSC ti TSC, v TRAU tng ng vi TS ny cng

khng c s dng.

Chc nng ca TRAU l:

- Chuyn i khi 260 bit m ho ting thnh 160 mu 8 bit theo lutA_PCM, v ngc li.

- To khung v ng b cc khi m ho ting.

- Tch knh thoi ang lm vic.

- iu chnh pha ca cc khi trn ng xung trc tip gim tr.

- Gi cnh bo ti BSC thng qua TSC.

___________________________________________________________________________________________________________________________ 35


36/122

- t ch kim tra lp theo yu cu ca BSC hoc MSC.

Chc nng ca TRCU l:

- Qun l khe thi gian TS0 trn ng truyn 2048Kbit/s.

- Gi v nhn cc bit trn giao din 2048Kbit/s.

- u ni knh bo hiu s 7 t TS16 trn ng truyn 2048Kbit/s t MSC

ti TS16 ca ng tryun 2048Kbit/s m BSC.

- Gi cnh bo ti BSC thnh qua TSC.

- Truyn cc bn tin OM ti TSC v BSC.

* Thit b ghp knh SM2M(2Mbit/s Sub Multiplexer).

B ghp knh cho mt mng truyn dn 2Mbit/s l thit b c lp m c

th c s dng khi TC c t ti MSC ghp 90 knh cho 16Kbit/s caba TRCU vo mt ng truyn 2Mbit/s.

Cc knh thoi v s liu chim cc khe thi gian m khng phi l bi s

ca 4. Bo hiu s 7 chim cc khe thi gian 20, 24 v 28. Khe thi gian 4, 8,

v 12 c dnh cho dch v ch s chuyn i kt cui MSC ln BSC.

Khe 16 trng.

B ghp knh c th c s dng hay khng ph thuc vo cu hnh ca

mng. Nu c s dng, n phi c t c u v ui ca ng truyn

dn.

Cc chc nng chnh ca SM2M l:

Ghp 3 30 knh 16Kbit/s cc khe thi gian ca ng truyn 2Mbit/s

thnh mt knh 90 cao tc trn ng truyn 2Mbit/s.

___________________________________________________________________________________________________________________________

BSC

BSC

Channeluer

LPADfor

TC

mainternace

MAINTERNA

CE

BSC/TCSMinterface A_ interface

CHOinfo15

16Kb

# 7Signalling1516Kb0 1 2 3 4 56 7

0

1

151617

TC

MSC

CHO info

15 PCMChannel

# 7Signalling

15 PCMChannel

31

151617

0

1

8

36


37/122

Gim TS0 ca giao din 2Mbit/s.

Gi cnh bo ti C thng qua TSC ti thit b d phng ng cao tc

HWRED ( High Way REDun dancy).

t ch lim tra vng.

Truyn cc bn tin O & M gia BSC v BSC.

3.2.GIAO TIP V TUYN :

Giao tip v tuyn l tn gi chung ca u ni gia MS v BTS giao tip s

dng khi nim TDMA vi 1 khung TDMA cho mt tn s mang, mi khung

gm 8TS hng t BTS n BS (ng xung).

3.2.1. Khi nim cc knh giao tip v tuyn:

Mng GMS/PLMN c dnh 124 knh sng mang , sng ny di tn:

- ng ln (MS-BTS) : 890-915MHz.

- ng xung (BTS-MS): 935-960 MHz

- Vit Nam, GMS s dng bng tn ng ln 890,2-898,4 MHz v ng

xung 935,2-934,4MHz. Mi tn s sng mang 200kHz trn mi sng mang

thc hin ghp knh theo thi gian ng vi mi khung TDMA ta c so knhbng 124x8(khe)=922 knh.

*Knh vt l:

Mt s TS ca mt khung TDMA mt sng mang l mt knh vt l th

mt sng mang GMS c 8 knh vt l, thng tin pht i t mt TS gi l

Burst.

*Knh lgc:

___________________________________________________________________________________________________________________________ 37


38/122

Knh lgc c ni khc nhau tu theo loi thng tin cn truyn cc knh

lgc c chia thnh knh lu thng (TCH) v knh iu khin.

*Knh lu thng:

L knh mang ting hoc m ho hoc s liu ca ngi s dng , l knh

ng ln v xung, im n im.

- Knh Bm hay ton tc TCH mang thng tin (ting m ho hay s liu) tc

tng 22,8kbit/s.

- Lm hay TCH bn tc mang thng tin (ting m ho hay s liu) tc

tng 11,4kbit/s.

*Knh iu khin: mang tn hiu hay s liu ng b

- Knh qung b BCH gm:

+ FCCH: Knh mang thng tin tn hiu chnh tn s ca MS knh ng

xung im ti a im.

+ SCH: Knh ng b mang thng tin ng b khung ca MS v nhn dngBTS, knh ng xung im ti a im.

+ BCCH: Knh iu khin qung b thng tin chung trn c s mt knh cho

BTS , knh ng xung im ti a im.

- Cc knh iu khin chung CCCH:

+ Knh tm gi (PCH): Dng gi MS, knh ng xung im ti aim.

+ Knh thm nhp ngu nhin (RACH): c dng yu cu mt knh iu

khin ng ring ng mt mnh (SDCCH) hay tr li tm gi hoc thm

nhp khi khi u hoc ng k cuc gi MS, knh ng ln im n

im.

+ Knh cho php thm nhp (AGCH): Dng dnh mt SOCCH hay trc

tip mt TCH cho MS, knh ng xung im - im.

___________________________________________________________________________________________________________________________ 38


39/122

- Cc knh iu khin ring:

+ SDCCH: Dng bo hiu h thng khi thit lp mt cuc gi trc khi

n nh mt TCH. Knh ln xung im-im.

+ Knh iu khin lin kt chm (SACCH) lin kt vi mt SOCCH hoc

mt TCH, l knh s liu lin tc mang thng tin lin tc nh cc thng bo

o c t trm MS v cng tn hiu thu t hin thi v cc trm ln

cn, thng tin ny cn cho chuyn giao v iu chnh cng sut MS v

ng b thi gian. Knh ln xung im-im.

+ Knh iu khin lin kt rt nhanh FACCH lin kt vi TCH v lm vic

ch ly cp nh trong trng hp chuyn giao (handover) ngi nghe s

khng thy c s gin on thng tin.

3.2.2. Cm:

Cm l mu thng tin mt khe thi gian km knh TDMA, c 8 khe thi

gian mt ln TDMA c pht i th c 1 cm ca mt loi thng tin.

*Cm bnh thng :NB

- Cc bit c mt m gm 57bit s liu hay ting v mt c ly cp.

- Chui hng dn l mu bit bit trc b cn bng c th thnh lp mt

m hnh knh.

- Cc bit ui TS lun l 0,0,0 gip b cn bng xc nh u v cui mu

bit.

- Khong bo v GP l mt khong trng cho php my pht dch ln haydch xung trong gii hn do khuyn ngh GMS qui nh.

___________________________________________________________________________________________________________________________

TB3

Cc bit c mtm58

Chui hngdn26

Cc bit c mtm58

TB3

GP8,25

0,577 ms156,25 bit

39


40/122

* Cm hiu chnh tn s: iu chnh tn s ca MS, n tng ng sng

mang cha b iu ch. Lp li ca mt cm gi l FCCH.

* Cm ng b (SM): Dng ng b thi gian ca MS

Khi ng b di d dng nhn bit v mang thng tin s khung TDMA cng

m nhn dng trm c s BS. Lp li ca cm l SHC.

S khung gip MS bit loi knh lgc ang c truyn bng iu khin.

Mt chu trnh nh s khung l 3,5 gi vi mi khung TDMA thi gian l

6,615ms.

* Cm thm nhp (AB): S dng thm nhp ngu nhin v c GP

dnh cho pht cm t trm di ng.

* Cm gi: c pht i t BTS v khng cha thng tin khun mu ging

nh cm bnh thng vi cc bit mt m c thay bi cc bit hn hp c

mu bit xc nh.

3.2.3. Sp xp cc knh lgc cc knh vt l:

Xt mt BTS vi n sng mang (truyn song cng, mi sng mang Co,....Cn

c 8 khe thi gian Ts. Vi Co ng xung, Tso c dng ch sp xp

cc knh iu khin.

___________________________________________________________________________________________________________________________

TB

3

TB

3

GP

8,250,577 ms

156,25 bit

Cc bit cnh 0

142

TB3

Cc bit c mtm39

Chui ng b64

Cc bit c mtm39

TB3

GP8,25

TB3

Chui ng b41

Cc bit c mtm36

TB3

GP8,25

012 0127 017

FS B C FS C C FS C C FS C C FS C C

Cc khungTDMA

BCCH CCCH ngxung

40


41/122

* Ghp cc BCH v CCCH TSo:

- TSo sng mang Co, ng ln khng xung cha cc knh FCCH, SCH,

v BCCH, n c dng thm nhp BCCH, FCCH, SCH, FCH, AGCH

ng xung ring RACH ng ln.

- i vi TS1 c s dng sp xp cc knh iu khin ring ln cc

knh vt l, o tc bit trong qu trnh thit lp cuc gi v ng k kh

thp nn c th c 8 SDCCH mt TS1. S dng TS hiu qu hn.

* Cc cch ghp knh TS1 :

- SDCCH + SACCH ng xung.

- SDCCH + SACCH ng ln

TS1 thng tin ca khe s c s dng cho cc knh lu khng TCH. TS

2-7 gi l cc knh lu khng lgc vi chu k lp li l 26Ts.

TSo: l cc knh iu khin lgc, chu k lp li 51Ts.

TS1: Cc knh iu khin lgc chu k lp li 102Ts.___________________________________________________________________________________________________________________________

012 0127 017

RRRRRRRRR 51 khung TDMA lintip

41


42/122

- Vi cc sng mang C1-CN dnh cho Ts0-7 u l TCH.

- Mi ch c 1Co v ch c sau TCH (Tc2-7).

- Vi sng mang b xung, c STS c th s dng cho TCH.

3.4. O CNG TRM DI NG:

* ch ri: Chn khi bt ngun di ng:

- MS gia 124 knh RF h thng GSM v tnh ton mc trung bnh cho

tng knh, MS iu chnh n sng mang mnh nht v tm xem n c pht

l BCCH hay khng, nu ng th MS c s liu BCCH xem c th kho

n ny khng, nu khng MS s tm n sng mang mnh th hai.

- MS c th c b nh BCCH v n s ch tm cc sng mang ny. Nu qu

trnh khng thnh cng MS thc hin qu trnh 1 BCCH, MS c thng

bo cn gim st cc sng mang BCCH no chn li kho n BTS

khc. Nh vy MS trn cp nht danh sch 6 sng mang mnh nht.

*Ch ni thng cuc gi: MS lin tc qua SACCH thng bo cho hthng cng tn hiu thu t BTS ln cn. BSC s dng cc php o ny

nhanh chng quyt nh cc ch khc khi chuyn giao cn thit. Vic o

c ln cn thc hin gia cc khong thi gian pht v thu khe Ts dnh

cho trm. Cng tn hiu ca mi phc v c gim stkhi thu Ts dnh

cho MS SACCH, cng tn hiu ca cc sng mang BCCH ln lt

c o theo qui trnh: Pht, o, pht, o,... gi tr trung bnh tng php o

cho tng sng mang c tnh ton v thng bo cho SBC. cc gi tr o

tng ng vi BTS cn o, phi xc nh nhn dng BTS BSIC pht

SCH trn Ts0, Co. Trong thi gian khung trng (ICLE) TCHC, TDMA-

267, BSIC cho BTS ln cn c.

___________________________________________________________________________________________________________________________ 42


43/122

*Nguyn l o MS:

(1): MS thu v o cng tn hiu

(2): MS Pht

(3): MS o cng tn hiu cho t nht mt ln cn.

(4): MS c BSIC SCH (TS0) cho mt ln cn

MS khng bit khi no xy ra TS0 sng mang BCCH ln cn nu phi o

trong khong thi gian 8Ts chc chn l Tso s xy ra trong qu trnh o.

Vic ny thc hin bng IDLE.

3.5. CC TRNG HP V TH TC THNG TIN:

3.5.1. Tng quan:

Trc khi kho st cc th tc thng tin khc nhau, hy kho st cc tnh

hung c bit ca 1 PLMN c tt c cc thu bao di ng, v th ta quan st

MS mt s tnh hung sau:

* Tt my:

Mng s khng th tip cn m my v MS khng tr li thng bo tm gi.

N s khng bo cho h thng v vng nh v (nu c) v MS s c coi l

ri mng.

*MS bt my ( trng thi ri):

___________________________________________________________________________________________________________________________

IDLE

10 2 7 10 2 7 10 2

10 2 7 10 2 7 10 2

1 2 3 1 2 4

Downlink

Uplink

25

25

24

24

45 MHz

43


44/122

H thng c th tm gi MS thnh cng, MS c coi l nhp mng. Trong

khi chuyn ng, MS lun kim tra rng n c ni n mt knh qung b

c thu pht tt nht. Qu trnh ny c gi l lu ng(Roaming). MS

cn thng bo cho h thng v cc thay i vng nh v, qu trnh ny cgi l cp nht v tr.

*MS bn:

Mng v tuyn c mt knh thng tin (knh ting) dnh cho lung s liu ti

v t MS trong qu trnh chuyn ng MS phi c kh nng chuyn n mt

knh thng tin khc. Qu trnh ny c gi l chuyn giao (Handover).

quyt nh chuyn giao h thng phi din gii thng tin nhn uc t MS v

BTS. Qu trnh ny c gi l nh v.

3.5.2. Lu ng v cp nht v tr :

Coi rng MS trng thi tch cc, ri v ang chuyn ng theo mt phng

lin tc MS c kho n mt tn s v tuyn nht nh c CCCH v BCH

TSo. Khi MS ri xa BTS ni vi n cng tn hiu s gim. mt thiim no khng xa bin gii l thuyt gia hai ln cn nhau cng

ti mc m MS quyt nh chuyn n mt tn s mi thuc mt trong cc

ln cn n. chn tn s tt nht n lin tc o cng tn hiu ca tng

tn s trong s tn s nht nh ca ln cn. Thng MS phi tm c tn

s BCH/CCCH t BTS c cng tn hiu tt hn tn s c. Sau khi t

kho n tn ss mi ny, MS tip tc nhn thng bao tm gi / cc thng bo

qung b chng no tn hiu ca tn s mi vn tt. Quyt nh vic thay

i tn s BCH/CCCH s c thc hin m khng cn thng bo cho mng.

Ngha l mng mt t khng tham gia v qu trnh ny.

Kh nng chuyn ng v nh ng thi vi vic thay i ni thng MS

giao tip v tuyn ti thoi im cn thit m bo cht lng thu c

gi l lu ng Roaming.-Khi MS chuyn ng n gia hai cll thuc 2 BTS khc nhau:

___________________________________________________________________________________________________________________________ 44


45/122

Ta bit rng MS khng h bit cu hnh ca mng cha n. gi cho MS

thng tin v v tr chnh xc ca n h thng gi i nhn dng vng nh v

(LAI) lin tc giao tip v tuyn bng BCCH.

Khi i vo cell Thuc BSC khc MS s nhn thy vng mi bng cch thuBCCH. V thng tin v v tr c tm quan trng ln nn mng phi thng bo

v s thy i ny, in thoi di ng qu trnh ny c gi l ng k

cng bc. MS khng cn cch no khc l phi c gng thm nhp vo

mng cp nt v t ca mnh MSC/VLR. Qu trnh ny c gi l cp

nht v tr.

Sau khi pht v tr mi ca mnh ln mng, MS tip tc chuyn ng

trong vng mi nh m t trn.

-Khi MS chuyn ng gia hai vng phc v khc nhau:

Trong trng hp c mt cuc gi vo cho MS, vic chuyn t mt vng

phc v MSC/VLR ny sang mt vng phc v MSC/VLR khc c nghi l

tuyn thng tin i qua mng cng s khc. tm c nh tuyn ng, hthng phi tham kho b ghi nh v thng tr HLR v th MSC/VLR s

phi cp nht HLR v v tr ca MSC/VLR cho MS ca chng ta.

Qu trnh cp nht v tr nh sau:

___________________________________________________________________________________________________________________________

MSCHLR VLR

MSC

VLR

(5) xo v tr

(6) tip nhnxo

(2)Yu cu cpnht v tr

(3) tip nhn vtr

(1) Yu cu nhtv tr

(4) Cng nhncp nht v tr

45


46/122

Sau khi cp nht v tr thnh cng HLR h thng s hu b v tr c, HLR

thng bo hu b v tr cho tng i MSC/VLR c xo v tr c ca MS c

lin quan.3.5.3.Th tc nhp mng ng k ln u:

Khi MS bt my n s qut giao tip v tuyn tm ra tn s ng, tn s

m MS tm kim s cha thng tin qung b cng nh thng tin tm gi

BCH/CCCH c th c. MS t kho n tn s ng nh vic hiu chnh tn

s thu v thng tin ng b

V y l ln u MS s dng nn phn mng chu trch nhim s l thng

tin ti / t MS hon ton khng c thng tin v MS ny, MS khng c ch th

no v nhn dng vng nh v mi . Khi MS c gng thm nhp ti mng v

thng bo vi h thng rng n l MS mi vng nh v ny bng cch gi

i mt thng bo Cp nht v tr mng n MSC/VLR.

T gi tr i MSC/VLR s coi rng MS hot ng v nh du trng dliu ca MS ny bng 1 c nhp mng co ny lin quang n IMSI.

3.5.4. Th tc ri mng:

Th tc ri mng lin quan n IMSI. Th tc ri mng ca IMSI cho php

thng bo vi mng rng thu bao di ng s tt ngun , lc ny tm gi MS

bng thng bo tm gi s khng xy ra.

Mt MS trng thi hot ng c nh du l nhp mng. Khi tt

ngun MS gi thng bo cui cng n mng ,thng bo ny cha yu cu

th tc ri mng. Khi thu c thng bo ri mng MSC/VLR nh du c

IMSI ri mng tng ng.

* Tm gi:

Cuc gi n MS oc nh tuyn n MSC/VLR ni MS ng k. Khi MSC/VLR s gi i mt thng bo tm gi n MS, thng bo ny c pht

___________________________________________________________________________________________________________________________ 46


47/122

qung b trn ton b vng nh v LA ngha l tt c cc BTS trong LA s

gi thng bo tm gi MS. Khi chuyn ng LA v nghe thng tin CCCH

MS s nghe thy thng bo tm gi v tr li ngay lp tc.

* Gi t MS:

Gi s MS ri v mun thitlp mt cuc gi thu bao ny s quay tt c cc

ch s ca thu bao b gi v bt u th tc ny bng cch n phm pht .

Khi ny MS gi i mt thng bo u tin n mng bng CCCH yu cu

thm nhp . Trc ht MSC/VLR s ginh ring cho MS mt knh ring ,

kim tra th loi ca thu bao b gi v nh du thu bao ny trng thi

bn . Nu thuee bao gi c php s dng mng MSC/VLR s cng nhn

yu cu thm nhp . By gi MS s gi i mt thng bo thit lp cuc

gi , tu theo thu bao b gi l c nh hay di ng s ca n s c phn

tch trc tip MSC?VLR hoc gi n mt tng i chuyn tip ca mng

PSTN c nh . Ngay khi ng ni n thu bao b gi sn sng thng

bo thit lp cuc gi s c cng nhn, MS cng s c chuyn n mt

knh thng tin ring. By gi tn hiu cui cng s l s khng nh thu bao.

* Gi n thu bao MS:

Gi s c mt thu bao A thuc mng c nh PSTN yu cu thit lp cuc

gi vi thu bao B thuc mng di ng.

- Thu bao A quay m ni nhn trong nc t ti vng GSM/PLMN. Ni

thng c thit lp t tng i ni ht ca thu bao A n GMSC ca mngGSM/PLMN.

- Thu bao A quay s ca thu bao B, so thu bao c phn tch GMSC.

Bng chc nng hi p GMSC gi MSISDN cng vi yu cu v s lu

ng (MSRN) n b ghi nh v thng tr (HLR)

- HLR nh s thu bao ca MS c quay v nhn dng GSM/PLMN

MSISDNIMSI

___________________________________________________________________________________________________________________________ 47


48/122


49/122

c kh nng trao i thng tin v bo hiu trong qu trnh cuc gi c th

ng b chuyn vng. Trong qu trnh hi thoi knh TCH dnh ring, MS

phi tp trung ln TCH ny v th khng th mt knh khc dnh ring cho

bo hiu. Mt l do khc na l s lng knh c hn nn h thng khng sdng 2 knh cho cng mt hng, vic t chc truyn dn s liu trn knh

TCH sao cho cuc ni chuyn cng nh thng tin v bo hiu c gi i

trn 1 knh. Lung s liu s c pht i theo mt trnh t chnh xc c

MS ln BTS c th phn bit gia cuc ni chuyn v cc thng tin bo hiu.

By gi ta quay li vic nh v, trc ht BTS s thng bo cho MS v cc

BTS ln cn v cc tn s BCH/CCCH. nh thng tin ny MS c th ocng tn hiu cc tn s BCH/CCCH ca trm gc ln cn, MS o c

cng tn hiu ln cht lng truyn dn TCH bn ca mnh. Tt c

cc kt qu o ny c kt qu o ny c gi n mng phn tich su

hn. cui cng BTS s quyt nh chuyn vng. BSC s phn tch cc kt qu

o do BTS thc hin TCH bn . Tm li BSC s gii quyt 2 vn :

- Khi no cn thc hin chuyn vng

- Phi thc hin chuyn vng ti BTS no

Sau khi nh gi chnh xc tnh hung v bt u qu trnh chuyn vng,

BSC s chu trch nhim thit lp mt ng ni thng n BTS mi. C cc

trng hp chuyn vng sau:

* Chuyn giao trong vng 1 BSC:

trng hp ny BSC phi thit lp mt ng ni n BTS mi, dnh

ring mt TCH ca mnh v ra lnh cho MS phi chuyn n 1 tn s mi

ng thi cng ch ra mt TCH mi. Tnh hung ny khng oif hi thng

tin gi n phn cn li ca mng. Sau khi chuyn giao MS phi nhn

cc thng tin mi v cc ln cn. Nu nh vic thay i n BTS mi cng

l thay i vng nh v th MS s thng bo cho mng v LAI mi ca mnhv yu cu cp nht v tr.

___________________________________________________________________________________________________________________________ 49


50/122

- Chuyn giao gia hai BSC khc nhau nhng cng mt MSC/VLR

Trng hp ny cho thy s chuyn giao trong cng mt vng phc v

nhng gia hai BSC khc nhau. Mng can thip nhiu hn khi quyt nh

chuyn giao. BSC phi yu cu chuyn giao t MSC/VLR. Sau c mt

ng ni thng mi (MSC/VLR BSC mi BSc mi) phi c thit

lp v nu c TCH ri. TCH ny phi c dnh cho chuyn giao. Sau khi

MS nhn c lnh chuyn n tn s mi v TCH mi. Ngoi ra sau khi

chuyn giao MS c thng bo v cc ln cn mi. Nu vic ny thay i

BTS i cng vi vic thay i vng nh v MS s gi i yu cu cp nht v

tr trong qu trnh cuc gi hay sau cuc gi.

- Chuyn giao gia hai vng phc v MSC/VLR

y l trng hp chuyn giao phc tp nht nhiu tn hiu c trao i

nht trc khi thc hin chuyn giao.

Ta s xt 2 MSC/VLR. Gi MSC/VLR c (tham gia cuc gi trc khi

chuyn giao) l tng i phc v v MSC/VLR mi l tng i ch. Tngi c s gi yu cu chuyn giao n tng i ch sau tng i ch s

m nhn vic chun b ni ghp ti BTS mi. Sau khi thit lp ng ni

gia hai tng i tng i c s gi i lnh chuyn giao n MS.

***

___________________________________________________________________________________________________________________________ 50


51/122

PHN II. CC CH TIU K THUT CA MNG GSM.

CHNG I. CU HNH TRM GC BTS.1.1. S KHI:

- BIE: Thit b giao din trm gc.

- TC: Cc b chuyn i m.

- SM: khi ghp knh con.

- DTC: B iu khin trung k s.

- CPR: B x l iu khin.

- TCU: Khi iud khin u cui.

- FU: Khi to khung.

- FHU: Khi nhy tn.

- CU: Khi sng mang.

- MCU: Khi ng h ch.

- OMU: Khi khai thc v bo dng.

1.2. CHC NNG CHUNG CA BTS:

Mi trm BTS phc v cho mt cung cp ng truyn v tuyn.

Cc chc nng c bn ca BTS c nu phn trn. BTS c gii

hn bi hai giao din:

- Giao din v tuyn ( gia BTS v MS ).

- Giao din BTS - BSC, giao din y c thc hin cc dng.

BGH

P

CU

FH

U

MCU

FU

B

IE

TCU

OMU

CPR

DTC

DTC

SM SM

B

IE

TC

TC

Tuchn

Tuchn

A bis

A

V tuyn /K bnggc

Truyndn

/k BSCTruyn

dn

BTS BSC


52/122

+ Giao din Abit khi BTS t cch xa BSC trn 10m ( cu hnh t xa).

+ Giao din ni b c gi l giao din trm gc (BSI) khi BTS v BSC

c t cch xa nhau di 10m ( cu hnh kt hp v khi khng cn

giao din Abit v l do khc ).

BTS m bo:

- ng ni v tuyn MS.

- Phn bng c s ca lp thu ph 1v 2. Phn y l giao thc thm

nhp ng truyn knh D(LAPD: Link Access Protocol on D

Channel) gia BSC v BTS v giao thc thm nhp ng truyn knh

D di ng (LAPDm: Link Access Protocol on D Mobile ) gia BTS v

MS. LAPDmc th s dng ng thi cho dch v bn tin ngn.

- Cc chc ng khai thc v bo dng ring cng vi chc nng qun

lcc timnng v tuyn.

* Cc tnh ng ca mt trm BTS.

- nhy my thu: Ln hn hoc bng -104dBm.

-B tr tr a tia: S cn bng cho php b tr tr a tia n 20s

-Nhy tn: Cho php s dng thm cc b thu pht phc v thm cho

nhy tn.

-Anten: BTS c th u ni n t anten pht v mt oc hai anten thu

( trng hp phn tp khng gian ). Anten c th v hng mt phng

ngang ( Omnirectional ) hay nh hng hnh qut1200 ( Sectorial

Anten ).


53/122

- Cng sut pht: Cng sut pht trc khi ghp chung vo anten l 26W

hay 69W ( hay 30W ). C th iu chnh cng sut tng nc 2dB.

1.3. CHC NNG CC KHI:

Mt BTS bao gm cc khi sau:

- Khi giao din trm gc

- Khi to khung.

- Khi nhy tn.

- Khi dng h ch.

- Khi sng mang.

- Khi ghp chung anten.

- Khi khai thc v bo dng.

S khi m t qu trnh x l v bin i tn hiu BTS c cho cc hnh sau:

* Nhim v ca khi ng h ch MCU l to ea cc loi ng h

sau:

- ng h tham kho cho b tng hp tn s.

- ng h bit 3,7s.

- ng h khung TDMA: 4,615ms.

- S khung ( FN ).

* Nhim v ca khi to khung gm:


54/122

- Thch ng tc s liu v ting ( chuyn i vo 16Kbit/s v ngc li

).

- M ho v gii m knh.

- ng b vi b chuyn i m t xa gim ti thiu thi gian tr.

- Ghp xen v kh ghp xen.

- Mt m ho v gii mt m.

- Gii iu ch v cn bng.

- To lp khung.

- iu khin cng sut my pht bao gm c DTX.

- Pht hin TACCH.

- Pht hin c ch th im lng (SID ).

- Gii m cm thm nhp chuyn giao.

- Nhim v ca phn pht ca khi sng mang ( CU ) gm:

- iu ch.

- Bin i nng tn.

- Khuych i v iu chnh n nh cng sut.

- iu khin to khung.

* Thc hin x l:

- Giao thc lp 2 ( LAPDm ) bao gm kim tra khung, qun l ng

truyn v tuyn.

- Giao thc lp 2 ( LAPD ) vi BSC.


55/122

- Giao thc lp 2 vi OMU.

- Giao thc lp 3 c th chia thnh:

+ nh tuyn cc bn tin trong sut lp 3.

+ X l v nh tuyn cc bn tin trong sut lp 3.

* Thc hin cc tnh nng:

- Qun l knh v tuyn.

- iu khin cng sut.

- o cht lng.

- Tm gi.

- Bo dng.

* Tham gia thc hin:

- nh trc thi gian.

- Gim st ( cc phn t ca BTS ).

- Qun l chuyn i m t xa.

* Nhim v ca phn thu khi CU gm:

MCU: Khi ng h ch

FU

Thchng giaodintrm gc

Mhoknh

Giaodinnhy tn

Giimknh

Giiiuch

iu khinkhi tokhung

ng hkhikhung

T MCUPhnphi

T/nBIE

Khi

thytn

CU

Giaodinviukhin

Giaotip

K/cng

sut

Bin inngtn

/CGMSK

Tnghp tns

Tnghp tns

Ly mu

Cnhbo

Bin ih tn

iu

khin

ngh

iukhinCn

hbo

Tuvo mythu

TX

RX

n khighpchung


56/122

- Bin i h tn.

- Ly mu tn hiu.

- Tnh ton cng in trng tn hiu thu.

* Nhim v ca b kt hp:

- m bo ni chung cc my pht ca CU vo mt anten pht bng cch

s dngcc b Circulator v cacs hc cng hng.

- Chuyn mch bo v cho knh BCCH.

- o kim h s sng ng cho tng knh v cho anten.

- u vng my pht vi my thu kim tra.

* Nhim v ca khi u vo my thu:

- Lc.

- Khuych i tp m nh.

- Phn chia tn hiu n cc my thu tng ng.

- T chc thu phn tp khng gian.

* Nhim v ca khi khai thc v bo dng OMUgm:

- Khai thc v bo dng cho cc khi khc nhau trongBTS.

- Giao din vi u cui khai thc ngi my.

a/

MF1

MF2

MFn

CH: Cnh hngb/

iu khin v trng

thi

K TNdphng

LcBT

Ghp

CU

1

CU

2

Chuynmch

BCCH

CU

n

Gimstphn x

Gimstphn x

Gimstphn x

Hc CH

F2

Hc CH

Fn

Hc CH

F1

Lc

u vngn mythu kim tra

Cnh boh s sngng

Ghp bngrng

Ante

n

K TN Ghp

chungCU1

LcBT

Ghp

KTN

K TN

dphng

Ghpchung CUn

uvngkimtra

uvngkimtra

Thu phn tp khnggian

Cc Anten

thuThu

chnh

Rle Rle

n khikhai thcv bodngOMU

MT1

MTn


57/122

CHNG II: PHNG THC HOT NG V CH TIU

K THUT CA MNG CELLULAR

2.1: KHI NIM V LU LNG:

Lu lng ca mt thu bao bt k c tnh bng cng thc:

A = nT/3600 [Erlang ].

Trong : n - S trung bnh cc cuc gi trong mt gi.

T - Thi gian trung bnh mt cuc gi (s).

A - Lu lng thng tntn nhi s dng.

V d: S liu thng k cho bit rng i vi mng di ng, th n

v T thng c cc gi tr nh sau:


58/122

N = 1: Trung bnh trong mt gi c mt cuc gi.

T = 120s: Thi gian trung bnh ca mt cuc gi l 120giy.

Vy lu lng ca mt ngi s dng l;

A = (1x120)/3600 = 0,033 = 33m Erlang.

Nh vy vi 1000thu bao s lu lng l 33 Erlang. T con s c

s ny gip ta tnh ton c s kng yu cu trong mt mng t ong.

2.1.1. Mc phc v GOS (Grade of Service):

c th quyt nh v b tr trm gc, cn bit c bao nhiu thu

bao v % cc cuc gi nghn c cho php %, cc cuc gi nghn

c xc nh bng cht lng cuc gi l mc phc v GOS.

Theo tnh ton trn mt thu bao cn lu lng l 0.033 Erlang

s chim knh TCH trong khong 3,3% thi gian. Vi 30 thu bao th n

chim khong 100% thi gian knh v tuyn, iu ny dn n nghn mc cao khng th chp nhn c. gim nghn ny cc knh ti

phi c lu lng t i hoc tng trn c s lulng cn thit. Nghn

chp nhn c hay GOS thng l t 2 - 5% y ta chn 2% vi mt

mc GOS ta c th tnh c s knh cn thit theo bng GOS.

2.1.2. Dung lng Traffic trung k v dung lng thu bao:

Khi nim trung k trong GSM c th hiu l cc TS (Time Slot)

dnh cho cc knh mang ting v sliu TCH. Cc thu bao khi thc hin

cuc gi s n nh mt TS tc mt knh nht nh. Nu nh trung k

c 13 knh cng hot ng th thu bao di ng c th s dng bt c

knh no m hin ti ang ri. Gi s c 1000 thu bao di ng na thu


59/122

bao cn mt dung lng l 33 m Erlang do vy c th ti 100% thi gian

ca 33 knh ny.

iu quan trng l phi bit c vi lu lng Traffic l bao

nhiu c th mang nhng knh ny nu ta s dng cp phc v GOS l

2%. Bng GOS s cho tnh c lu lng (Erlang) theo s knh (n)

khc nhau v tc dch v ( kh nng nghn cuc gi E) GOS l khc

nhau.

V d: S knh n = 30.

Nghn GOS= 2%.

Tra bng ta c lu lng N= 21,93 erlang.

T y ta c th tnh c dung lng ( s lng) thu bao cn

phc v. V mi thu bao di ng cn mt lu lng l A=0,033 Erlang.

Do vy vi N= 21,93 th c th phc v c s thu bao l :

S=N/A=N/0,033[thu bao](*).

Theo th d trn th:

S=21,93/0,033=644 [thu bao].

Cng thc (*) rt quan trng, n gip ta tnh c s thu bao cn

phc v theo s knh TCH cn thit t c phng hng nh dung

lng cn m rng mng.

2.1.3 Hiu qu s dng trung k:

Hiu qu s dng trung k l hiu sut s dng ti a knh m

khng gy ra tc nghn ti a c cho knh . Hiu qu s dng trung

k c tnh theo cng thc:


60/122

H=N-N x E/n=N(1-E)/n.

Trong : N l lu lng Traffic trung k.

E nghn GOS thng chn l 2%

n: s knh TCH.

Hiu qu s dng trung k th hin kh nng ti a ca mt knh.

V d trn vi lu lng trung k l 21,93 erlang do vi 33 knh th

mi knh s s dng 21,941/33= 56% thi gian.

Di y l bng hiu qu cc trung k 6, 14, 22, 30, 38, v 45

knh.

S knh (n) Traffic(N) ng vi

erlang=2%

Hiu qu s dng knh (H).

6

14

22

30

38

45

2,28

2,20

14,90

21,93

29,17

35,61

0,37

0,57

0,66

0,71

0,75

0,78

Vi bng trn ta nhn thy trung k 45 knh c hiu qu s dng

knh gp 2,1 ln trung k 6 knh. Nh vy s knh trung k TCH cng

ln th hiu qu s dng trung k cng cao.

2.2. MNG T ONG:


61/122

2.2.1. Cc thng s:

Cn phi d on dung lng cn thit (lu lng phc v )

a ra s knh cn thit thc hin theo yu cu cht lng phc v. Gi

s cn phi phc v 1000 thu bao di ng vi tng s 33 Erlang trong

mt vng nh v gm 5 cell vi mc phc v GOS = 2% V tng s

knh cn thit l 60 knh. Bng di y cho thy lu lng phc v

phn b theo tng vng ( cell ) nh sau:

Cell Lu lng (%) Erlang S knh

A

B

C

D

E

40

25

15

10

10

13,20

8,25

4,95

3,30

3,30

20

14

10

8

8Tng 5 cell 100 33.00 60

Ta nhn thy rng lu lng phc v phn chia khng ng u

cho mi vng, ti vng mt thp th s knh TCH i hi t hn,

ngc li vi vng mt cao th s knh TCH cn nhiu hn. y cng

l mt c s quan trng cho thit k mng nhm p ng lu lng cnthit cho tng vng kho st. Ngha l dung lng mng t ong c nh

c bi phn b lu lng v s knh cn thit cho tng vng.

2.2.2. Lu lng knh logic:

Trong GSM mi tn s c 8 knh c ghp, tc l c 8 knh

trong mi trng hp n gin nht ( bi v thc t mi c th c


62/122

nhiu tn s ). Trong mi ny mt knh s dng cho thng tin qung b

cc knh cn li s dng cho knh ting v s liu TCH ( knh lu thng

0 v knh cui cng dng cho thit lp cuc gi SDCCH.)

- knh TCH: Thi gian trung bnh ca cuc gi l 120 giy, mi

thu bao cn 1 Traffic l 0,033 Erlang do cuc gi trung bnh trong

gi cao im l:

A 3600/T = 0.033 3600/120 = 1

- knh SDCCH: Thi gian cho SDCCH l 3s. Cho rng y c3 ln cp nht v tr khi thit lp cuc gi v 4 knh SDCCH s dng cho

mt thu bao di ng vo gi cao im, do vy lu lng SDCCH cho

thu bao di ng s l: 4 3/3600 = 0,033 Erlang, c ngha l bng 1/10

ca Traffic cho thu bao di ng .

Mt knh vt l vi 48 knh SDCCH c lp t bng Erlang vi t

l nghn GOS = 2% ta tra bng c dung lng l 3,6271 Erlang. iu

ny c ngha l 8 knh SDCCH/8 c th phc v c 3,6271/0,033

=1099 thu bao m phc v 1099 thu bao th dung lng ca knh

TCH cn thit l 36,271 Erlang, tra bng tm c 45 knh TCH . Nh

vy sau 5 sng mang truyn i s c thm mt knh SDCCH cn thit

thit lp cuc gi.

Ta bit cu trc ghp knh Radio Interface: Vi mi tn s

tng ng vi mt FU ( hay mt TRX ) th s dnh TS0 v TS1 cho cc

knh iu khin, cc TS cn li dnh cho TCH. Di y l bng thng

k TCH, lu lng Erlang, s thu bao phn b FU ( TRX ).

FU in Cell 1 2 3 4 5 6 7

TCHs Channel 6 14 22 30 37 45 53


63/122

Erlang 2,94 8,20 14,9 21,93 28,3 35,6 43,1

Subcriber 89 248 451 664 857 1078 1306

2.2.3.Cht lng phc v:

Cht lng phc v nh ngha kh nng thit lp v kt cui cuc

gi cho cc thu bao di ng. Bao gm t l ri cuc gi, t l ri trn

knh TCH, nghn trn Air Interface, Handover v cc vn truyn dn.

* T l ri TCH ( TCH Failure Rate):

T l ri trn knh TCH ph thuc vo 3 yu t sau:

- Tng s knh TCH khng th t n trm di ng trong th tc

thit lp thng thng khi trm di ng chuyn t knh SDCCH sang

TCH.

- Tng s cc ln chuyn giao trong khng thnh cng dn n

trm di ng quay li knh c hoc cuc gi b ri.

- Tng s cc cuc gi b ngt khi cc trm di ng t c

n knh TCH v khng lin quan n th tc chuyn giao nhng cuc

gi b ngt do cc nguyn nhn nm ngoi vng bao ph sng, pin ht

nng lng, tt ngun.

* T l ri cuc gi ( Droppled Call ):

- Ri cuc gi xy ra khi chuyn giao khng thnh cng.

- Ri cuc gi cng xy ra khi gp li trn knh TCH

- T l ri cuc gi c o t trn airterface vi thit b o K1-

103 v phn mm x l AGLAE.


64/122

* Nghn trn Airinterface:

- Nghn trn Airinterface xy ra trn SDCCH trong qu trnh thit

lp cuc gi.

- Nghn trn Airinterface xy ra trn TCH trong qu trnh tin hnh

cuc gi.

* Handover:

- T l Handover thnh cng.

- T l Handover tht bi.

2.2.4. Cu trc cc phn t mng:

i vi mng di ng t bo mt t th cc BTS c th coi l cc

thnh phn ch yu ca mng. Do ta c th gi cc BTS l cc phn

t ca mng GSM cng vic thit k mng sau khi tnh ton c

lu lng v cht lng phc v s l lp cu hnh cho cc i trm,tc l BTS hay cc phn t mng.

* La chn v tr t trm:

- Kt qu vic phn tch mi trng a l v vic cc i BTS

c xut phi nh gi c mi nguy him do phn tn thi gian.

Cc mi trng in hnh m c th xy ra phn tn thigian:

+ Cc vng ni.

+ H ao vi b dc ng hoc xy dng nhiu nh ca.

+ Cc thnh ph nhiu i.


65/122

+ Cc to nh cao tng.

Trong tt c cc trng hp trn khi hiu s qung ng i gia

tn hiu i thng v phn x t cc vt cn ni trn ln hn ca s cn

bng (4,5 Km) s ny sinh vn .

C hai cch trnh t phn tn thi gian c hi nh sau:

- t BTS gn ti vt phn x nht, s bo m hiu s qung

ng nm trong gii hn b cn bng.

- Hng anten trnh vt phn x nu BTS t xa vt phn x.

Anten phi c t s hng trc trn hng cao.

* Cc khi nim v i trm:

- Site: Trm c th l mt BTS nu s dng anten Omi hoc 3 BTS

nu s dng anten secter.

- Cell: mi tng ng 1 BTS, trong mi c th c nhiu tns.

- TRX: Trm thu pht bao gm anten pht kt hp.

- FU: Frame Unit tng ng vi mt tn s v bng TRX. Cc Site

c th gm ti a 3 BTS. Mi BTS c th c gm t 1 n nhiu FU

(TRX).

2.2.5. L THUYT MCH CELL - TN S:

Trn c s tnh ton lu lng cn phi vch ra mu v quy

hoch tn s khng ch cho mng ban u m cho c cc giai on pht

trin tip theo.

* Quy hoch Cell:


66/122

Omni Cell split phrase 0 Cell split phrase 1

- Omni cell: Cell c to bi hnh trn v ngi ta s dng anten

ng hng do trng bc x ra mi hng ca Cell l nh nhau .

kiu ny c quy hoch cho vng c mt lu lng thp.

- Cell split phase 0: Cc cell c tng trng bi cc hnh lc

gic, s dng cell cho mt site. Site ny dng anten sector ra 3 hng

mi hng tng ng vi vi mt cell. Gc phng v ca cc antenphn cch nhau 1200. Mi cell s dng cc anten pht 600 v 2 anten thu

phn tp 600 cho mt gc phng v. Quy hoch cell kiu ny cho vng

c mt cao.

- Cell split phase 1: c pht trin t phase 0 bng cch t

mi cell ban u mt Site sector. Site chia nh cell thnh 3 cell mi

nh vy s cell s tng ln gp 3 ln mi cell ban u . Phase1 c

dng nhng vng c mt rt cao.

- Cellular Network: Mng s s dng rt nhiu cell, tu thuc

vng c mt cao hay thp m ngi ta la chn cc kiu Omni hay phase

0, phase 1, phase 2.

* S dng li tn s:


67/122

Nguyn l c s khi thit k h thng t ong l cc mu c gi

l mu s dng li tn s . S dng li tn s l s dng cc knh v

tuyn cc vng tn s mng ph cho cc vng a l khc nhau, ccvng ny phi cch nhau mt c ly ln mi nhiu giao thoa ng

knh C/I c th chp nhn c. Mu s dng li tn s c k hiu l

N/M trong N l v tr t Site, M l nhm tn s . Vi R l bn knh

cell s dng li tn s v D l khong cch gia hai cell s dng chung

tn s, hn ch t s C/I th phi tho mn:

D/R=(3m)1/2.

Trong mng thng tin di ng c 3 mu s dng li tn s sau:

* Mu 3/9 D = 5,2 R

* Mu 4/12 D = 6 R

* Mu 7/21 D = 7,9R

Mng GSM ca VSM s dng mu 4/12.

- M hnh 3/9: s dng nhm 9 tn s trong mt mu s dng li

tn s 3 i.

G0

D0

E0

F0

A B C


68/122

- M hnh 4/12: s dng nhm 12 tn s trong mt mu dng li

tn s 4 i.

- M hnh 7/21: s dng nhm 21 tn s trong mt mu dng li

tn s 7 i.

- Ch nh knh cho mu s dng li tn s:Nguyn tc ch nh knh cho cc mu s dng li tn s v cc tn

s sng mang trong vng 1 BTS phi khc nhau sng mang v cc tn

s trong cng mt trm ( Site ) hay cng mt v tr phi cch nhau Nsng

mang. Do bng tn ca GSM l hn tr do cc nguyn tc trn dn n

s sng mang trong 1 Cell l rt hn ch . Cch phn b sng mang nh

bng di y:

Bng ch nh knh cho m hnh 4/12:

Nhm knh

tn

A

1

B1 C1 D

1

A

2

B2 C2 D

2

A

3

B3 C3 D3

Cc knh 1

13

2

14

3

15

4

16

5

17

6

18

7

....

8

...

9

....

10

....

11

...

12

...

B

1E1

F1

E2C1

B3

B2

C1

C1

C3

C2

A1

C2

C3

C

3

C

2

F

1

A

3

A

2

D

1D1

F3

F2

D3

D2

D3

D2

E2E3

E3

M HNH MU S DNG LI TN S7/21

A1

B1

B3 B2 A1

A2A3C1A2A3

B1 B1C3 C2

A1

A3 A2

B2B2B3 B3

MU S DNG LI TN S3/9

C1

C3 C2D1

D3

D2

B1

B3 B2A1

A3 A2C1

C3 C2

D1

D3

D2

B1

B3B2

A1

A3 A2C1

C3 C2A1

A3 A2

D1

D3

D2

B1

B3 B2

B2

B1

B3

C1

C1

C3

C2

C2

C3

B2

B1

B3

A1

A3 A2

D1

D3

D2

M HNH MU S DNG LI TN S4/12


69/122

Nhn xt: Mu 4/12 s dng nhm 12 tn s: A1, a2, A3, B1, B2,

B3, C1, C2, C3, D1, D2, D3. Trong c php s dng 4 i ( Site ):

A, B, C, D. Vy theo mu s dng trn cc sng mang cng Cell cchnhau 12 sng, cn cc sng cng v tr cch nhau 4 sng.

V d: Tn s 13 cel A1 cch nhau 12 sng mang.

Tn s 1 v 5 SiteA cch nhau 4 sng mang.

- Kh nng p dng:

+ M hnh 3/9: M hnh ny c sng mang dng trong 1 cell l

tng i ln, tuy nhin khong cch di tn gia cc sng mang l nh,

do kh nng nhiu ng knh C/I, nhiu knh ln cn C/A l cao. Kh

nng p dng cho nhng vng c mt my di ng cao, kch thc

Cell l nh nhng vng ph sng d dng trnh c nhiu cho phainh.

M hnh ny ph hp phc v INDOOR cho cc khu cao tng.

+ M hnh 4/12: M hnh ny s dng cho nhng vng c mt

trung bnh do c s knh trong 1 cell t hn. Nhiu ng knh t khi l 1

vn ln. Vi m hnh ny kch thc Cell c th m rng ph hp vi

cc vng c mt trung bnh v t nh cao tng. C th phc v

INDOOR v INCAR.

+ M hnh 7/21: C th phc v cho nhng khu vc c mt

thp, do s lng knh trong mt cell l nh. Ta thy loi ny c khong

cch di tn gia cc knh ln cn v cc knh cng cell tng i ln.

Cc cell ng knh v nhiu cch nhau xa do khng c hin tng

nhiu ng knh v nhiu ln cn, m bo cht lng cc vng ph

sng. Do n c s dng khithunh cc cell thch hp vi mt


70/122

mydi ng ngy cng tng v nhng vng ph sng kh c kch thc

cell tng i nh.

- D on ng truyn C/I, C/A, C/R:

T mt v tr t BTS tin hnh kho st v truyn dn v tuyn,

trong cn d on cc thng tin v bn . Khi kho st cn s dng

cc phng tin pht sng trne ca gip cho vic o c cc v trkhc

nhau trn cng mt BTS. D on truyn lan l mt cng vic rt kh

khn v n b nh hng bi nhiu yu t nh a hnh, tn s, cao

anten thu pht.... Do khi thit k, d on cc mc nhiu, phn x,

phainh phi s dng cc thit b chuyn dng, cc cng thc l thuyt

cng nh s liu v bn . Tn hiu c o c cc vng a hnh

khc nhau, c mc khc nhau nh trong nh, trong xe t. Tt c u d

on cho vic truyn lan mt cch chnh xc.

D on cha chnh xc v mc lu lng c phn b, dnn kh nng c qu ti, mc nghn khng chp nhn c, c lu

lng thp khng hiu qu, nhng iu n n yu cu m rng

mng.

S m rng mng s c nh hng n phn mng ang hot ng

bnh thng. N c th l nhiu ng knh,chuyn giao khng tt... Do

qu trnh thit k l mt cng vic phc tp. Sau khi lp t h thngphi kim tra cc yu cu t ra, ri mi a mng vo khai thc.

PHN III. THIT K M PHNG BO HIU

S 7 TRONG MNG GSM


71/122

CHNG I: H THNG BO HIU S 7

TRONG MNG DI NG

1.1.Tng quan:

Bo hiu trong mng di ng phc tp hn trong mng in thoi

thng, v cc thu bao di ng MS c th di chuyn quanh mng nn

phi c yu cu cp nht v tr a l ca cc MS (vo ti) v s l

s thay i sang knh lu lng mi (chuyn ) khi MS ang di

chuyn t ny n khc. iu ny yu cu phi c mt h thng

bo hiu nhanh v mnh.

Trong tt c cc h thng GSM ang hoc s s dng h thng bo

hiu s 7 th u s dng chung phn MTP nhng cc phn ca ngi

s dng khc nhau c s dng cho cc h thng khc.

1.2. Cc thnh phn ca ngi s dng trong mng GSM:

1.3. Phn ng dng di ng MAP (Mobile Aplication Part).Phn ng dng di ng (MAP) cung cp cc th tc bo hiu cn

thit c yu cu trao i thng tin gia cc phn t ca mng

GSM, m hnh OSI, MAP trn TCAP, c MAP v TCAP u thuc

lp 7.

i vi cc dch v khng u ni c MAP s dng th ISP (phn

dch v trung gian) c xem l trong sut c ngha l khng c sdng v vy TCAP phi hp ghp u ni vi phn iu khin bo hiu

SCCP cng vi phn chuyn giao tin bo MTP ph thuc nh mt nh

cung cp dch v ca mng. MAP c chia lm 5 thc th ng dng

MAP - MSC, MAP-VLR, MAP - HIR, MAP - EIR v MAP - AUC. Tt

c nhng thc th ny mi ci c phn nh ti mt s phn h SSN.

BSSMAP MAP

TCAPBSSAP

TSDNISUP TUPSCCP

Phn chuyn i bn tin MTP

Bo hiu s 7 c lin quan n cc sn phm s dng trongmng di ng

Mc 1-3

Mc 4-7

Thc thng dng MAP - MSC

Phn ng dng di ng MSCASE

1

ASE

2

ASE

n

TCAP (ASE ) Phn lp phn t

PHN LPGIAO DCH

SCCP

MTP

MAP- HLR

MAP - VLR MAP- EIR

MAP = AUC

SSN SSN SSN

CC THC TH NG DNG AE V C P.T NG DNG ASE


72/122

Cc SSN c SCCP s dng nh a ch mt thc th no ca

mng GSM.

Mi AE bao gm mt s cc phn t ng dng ASE. Cc ASE c

nhm li nh l cc ASE chung v cc ASE c bit. TCAP l mt

ASE chung v lun lun cha cc MAP - ASE.

Cc ASE h tr vic ho mng ca cc AE v bao gm mt hoc

vi s hot ng c s dng kt hp thc hin mt nhim v no

.

V d v hot ng s dng MAP:

- Cp nht v tr.

- Bi b v tr.

- Cung cp s chuyn vng.

- Vo s liu thu bao.

- Pht cc tham s.- Tc ng cc dch v b xung.

- Thc hin chuyn v.v....

V d v t hp cc hot ng thc hin mt nhim v no .

Khi mt thu bao di ng mi MS xut hin thuc v mt VLR no

, th b ng k v tr trong MLR c cc MS thuc n, phi c cp

nht.


73/122

B ng k trong HLR, lc ny MS c ng k cng phi

c cp nht vi mt vi s liu thu bao cn thit. Nu MS mun

thc hin hoc thu cuc gi. Bo hiu ny cn thit thc hin nhimv ny nh sau:

1.4. Bo hiu gia MSC v BSS (BSSAP).

MSC v h thng trm c s BSS c ni vi nhau bi mt knh

PCM. Ngoi mt s cc knh thoi hoc s liu, cn c cc khe thi

gian cho bo hiu. S bo hiu khi u ni thit lp cuc gi, chuyn ,

gii phng cuc gi v.v... knh ny thng c s dng phc vmt hoc nhiu trm thu pht c s BTS. Cc giao thc c s

dng cho bo hiu gia MSC v BSS (giao tip A) l BSSAP (phn

ng dng ca BSS), SCCP v MTP, hnh sau:

Phn iu khin u ni bo hiu SCCP cung cp kh nng mang

thng tin NSC v BSS. SCCP cung cp hai nguyn tc bo hiu khc

nhau, bo hiu khng u ni CL v bo hiu u ni nh hng CO.

MS = X ang vng ca ti

OK! Ti cp nht vi TCAPHLR

TC - yu cu h tr (Upl, MS = X )

TC BT UTC - kt qu ( log Upd )

TC tip tc

TC yu cu h tr ( Upd cat)TC tip tc

TC kt qu ( cat Upl ) Hot ng

Hot ng

Giao dch

TC kt thc

MLRVLR

VLR

BSSAP

SCCP

MTP

DTAP DTAP

Phn lp phn b

BSSAP

SCCP

MTP

DTAP DTAP

Phn lp phn b

Giao tip

MSC BSS

Bo hiu gia MSC v BSS


74/122

Khi mt s cc tin bo hiu lin quan c pht i, s u ni bo

hiu logic c th c thit lp v cc tin bo u ni nh hng c

th c pht u ni bo hiu.

BSSAP pht cc tin bo c lin quan n mt MS c th phng

thc u ni nh hng SCCP.

- Bo hiu ca BSSAP.

BSSAP x l hai nhm tn hiu.

+ Tin bo chuyn giao trc tip gia MSC v MS, chuyn giao qua

BSS. S chuyn giao ny l iu khin cuc gi nh lnh rung chung

ti mt MS c th v cc tin bo qun l di ng.

+ Cc tin bo qun l gia MSC v BSS qun l ngun iu

khin chuyn , lnh nhn tin v.v...

BSSAP c hai chc nng ca ngi s dng khc nhau cho cc

nhm trn. Phn ng dng chuyn giao trc tip DTAP v phn ng

dng qun l BSS ( BSSAP ).

S phn b tin bo BSSAP gia BSS MAP v DTAP c thc hin

lp giao thc trung gian gia SCCP v BSS MAP/DTAP c gi l

lp phn b ( xem hnh trc ). Giao thc i vi phn lp ny bao

gm s qun l mt hoc hai octec khi s liu phn b. Mi tin bo

BSSAP cha trong trng s liu ca ngi s dng SCCP phi c

mt khi s liu phn b nh l tip u theo tin bo DTAP hoc

BSSAP c th ( xem hnh sau )

Tin bo DTAP cng l mt octec, mt trng khi s liu phn b

gi l nhn dng u ni knh s liu DLCI. N c s dng nhn

KHI

S LIU

PHN B

di

Tin bo

Phn bit

diLoi tin bo

P.t thng tin

P.t thng tin

Phn bit di

Loi tin bo

TI PD

P.t thng tin

P.t thng tin

BSSAP BSSMAP DTAP

Khun dng ca tin bo BSSAP


75/122

dng knh v tuyn v cng xc nh gi tr khi nhn dng im

truy cp dch v SAPI s dng knh v tuyn ( v v SAPI = 0 ngha

l bo hiu).

TI hnh trn l khi nhn dng giao dch v PD l khi phn bit

giao thc.

Cc tin bo BSSAP.

- C ba loi tin bo xc nh BSSAP (hnh sau ).

- Tin bo BSSMAP.

- Tin bo DTAP.

- Tin bo khi u MS.

Cc tin bo BSSMAP:

Cc tin bo BSSMAP c s dng qun l ngun, iu khin

chuyn v.v... Tin bo BSSMAP c chia thnh hai loi tin bokhng u ni v tin bo u ni nh hng ( xem hnh sau).

MngDTAP

MSC

MS

BSSMAP

Tin bo khi u MS

S khc bit logic gia cc tin bo


76/122

Cc tin bo BSSMAP

Khng u cuiCHN

Tha nhn chn

Paging (nhn tin)

Thit lp li

Tha nhn thit lp li

Gii toTha nhn gii to

u ni nh hng

YU CU PHN NH

Phn nh xung

S c phn nh

Ra lnh phng thc mtm

Cp nht li

Lnh xo

Xo xong

Yu cu xo

Thng tin y ca lp 3Lnh chuyn

S c chuyn

Chuyn c thc hin

Yu cu chuyn

Chp nhn yu cu chuyn

Documents

Tong Quan Ve He Thong Mang Gsm 9246