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Trc s pht trin v cng mnh m ca cc dch v s liu, trc xu hng tch
hp v IP ho t ra cc yu cu mi i vi cng nghip Vin Thng di ng. Mng
thng tin di ng th h ba ra i khc phc c cc nhc im ca cc mng thng
tin di ng th h trc . Tuy nhin, mng di ng ny cng c mt s nhc im nh:
Tc truyn d liu ln nht l 2Mbps, vn cha p ng c yu cu ngy cng cao
ca ngi dng, kh nng p ng cc dch v thi gian thc nh hi ngh truyn hnh l
cha cao, rt kh trong vic download cc file d liu ln,cha p ng c cc yu
cu nh: kh nng tch hp vi cc mng khc (V d: WLAN, WiMAX,) cha tt, tnh
m ca mng cha cao, khi a mt dch v mi vo mng s gp rt nhiu vn do tc
mng thp, ti nguyn bng tn t,
Trong bi cnh ngi ta chuyn hng sang nghin cu h thng thng tin di
ng mi c tn gi l 4G. S ra i ca h thng ny m ra kh nng tch hp tt c cc
dch v, cung cp bng thng rng, dung lng ln, truyn dn d liu tc cao, cung cp
cho ngi s dng nhng hnh nh video mu cht lng cao, cc tr chi ho 3D linh
hot, cc dich v m thanh s. Vic pht trin cng ngh giao thc u cui dung lng
ln, cc dich v gi d liu tc cao, cng ngh da trn nn tng phn mm cng cng
mang n cc chng trnh ng dng download, cng ngh truy nhp v tuyn a mode, v
cng ngh m ho media cht lng cao trn nn cc mng di ng.
Hin nay th trng di ng Vit Nam c nh gi l tng trng ng th 2 trn
th gii sau Trung Quc, s thu bao khng ngng tng, nhu cu v vic s dng cc dch
v v cc dch v a phng tin ngy cng cao v cng i hi cao hn trong tng lai.
Do vic nghin cu mt cng ngh mi p ng cc nhu cu th trng trong tng
lai l rt cn thit.
Hin nay Viettel a vo s dng GPRS p ng nhu cu s dng cc dch v
d liu ngy cng cao ca cc thu bao. Cc dch v ch yu ca GPRS nh: WAP, truy
nhp Internet c hai phng thc l truy nhp gin tip v truy nhp trc tip, dch v nhn
tin a phng tin, video, xem cc on phim ti v, xem video trc tuyn. Ngoi ra cn c
dch v thng mi in t di ng, dch v ngn hng, qung co trn in thoi di
ngdo gi cc cn cao nn cc loi bao c thu nhp trung bnh v cao. Da trn nhu
cu th trng Vit Nam, hin ti chng ta thy rng nhu cu chnh trong thng tin di ng
vn l dch v thoi truyn thng, dch v d liu cng bt u tng trng, theo d on
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tng s thu bao c nhu cu dch v d liu chim khong 50% vo nm 2010. Vi i
sng thu nhp ngy cng cao ca ngi dn, nhu cu cc dch v cht lng tt ngy cng
ln, th mng di ng Viettel ngy cng phi nng cp p ng c cc nhu cu ny.
Mt khc, xu hng chung trn th gii l hi t tt c cc mng vin thng li vi nhau.
Do , yu cu pht trin mng thng tin di ng ln th h 4G c tc cao, s dng all
IP c kh nng tch hp vi cc mng khc l yu cu tt yu ca mng di ng Viettel.
ti Nghin cu ng dng cng ngh 4G cho mng di ng di ng Viettel
Mobile c a ra khng ch nhm mc ch tm hiu, nghin cu cc dch v m n p
ng m cn c gng a vo p dng Vit Nam c th l trn mng di ng ca
Viettel.Vi mc ch ti nghin cu ca chng ti dc chia lm 4 chng:
Chng 1: Xu hng pht trin cng ngh v dch v ca cc mng di ng
Chng 2: M hnh cu trc mng 4G
Chng 3: Dch v v cht lng dch v trong mng 4G
Chng 4: L trnh tin ln mng thng tin di ng 4G cho Viettel Mobile
Vi vic trin khai ti Nghin cu ng dng cng ngh 4G cho mng di ng di
ng Viettel Mobile , Viettel m ra mt c hi mi, ng lc mi cho s pht trin
cng ngh mng cng nh thng mi in t trong thi i kinh t s hin nay, khng ch
cho cng ty m cn mong mun s ng gp mt phn vo s pht trin trong lnh vc
vin thng cng ngh thng tin ca nc nh. cng l mong mun ln nht ca nhng
ngi thc hin ti ny.
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CHNG 1
XU HNG PHT TRIN CNG NGH V DCH V CA CC MNG
DI NG
ngi
dng.
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Hnh 1.1 Cc th h di ng
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5.
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Trung
s
cng
ITU-T,3GPP,
Quc
ngh
quan
hip
(CCSA)
trng
hi
tiu
v
ca
4G
chun
cc
c
chun
m
vin
khc.
nh
sau:
OFDMA
Ghp knh phn chia tn s trc giao OFDM khng ch to nn li ch r rng cho thc thi
lp vt l, m cn hp nht vic ci thin hiu nng lp 2 nh vic a ra thm mt mc
t do. Nh vic s dng OFDM c th khai thc min thi gian, min khng gian, min tn
s v thm ch c min m ti u ho vic s dng knh v tuyn. Chc chn rng n c
u th ln vi truyn dn trong mi trng a ng vi vic lm gim thiu s phc tp
ca b thu.
Tn hiu c chia thnh cc sng mang nh trc giao, trn mi sng mang tn
hiu l bng hp (vi KHz) v v vy trnh c hiu ng a ng, to nn mt khong
bo v chn vo gia mi tn hiu OFDM. OFDM cng to nn mt li v phn tp tn
s, ci thin hiu nng ca lp vt l. N cng tng thch vi nhng cng ngh m rng
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ny
ch
dng
trong
cc
tnh
hung
ph
rt
khan
him.
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-Kt lun:
Cc dch v v cc trnh ng dng cho 4G vn ang c nh ngha, n pht trin v
dch chuyn theo nhu cu ngi s dng. Cc ng dng 4G hng ti phc v cho th
trng khch hng c nhu cu ln v cht lng dch v cng nh s a dng ca dch v.
Vi kh nng ca mnh, 4G thc s p ng c cc nhu cu v a dch v ca khch
hng hin ti v trong tng lai. Chng ny mi ch gii thiu v a ra mt s loi hnh
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CHNG 2
M HNH CU TRC MNG 4G
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dng nhiu dng dch v khc nhau nh PSTN, ISDN, internet, WLAN, WiMAX,vv, m
khng cn quan tm ti dng thit b ang s dng cng nh vic h ang u.
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Hnh 2.3: Ngi dng cc mng khc nhau c th truy nhp vo h thng
c. m bo cht lng dch v cho cc ng dng a phng tin trn nn IP:
m bo cht lng dch v, cn s kt hp cht ch gia cc lp truy nhp,
truyn ti v cc dch v Internet. c bit i vi cc vn v tr mng, bng thng
dch vvv. Mng 4G yu cu tc truyn d liu cao, tr nh, dch v thi gian
thc,
cht
lng
cao.
vi
tt
cc
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thng
vin
thng.