H thng ha lch s pht trin ca mng thng tin di ng t 2G ln 4GMc lc 1. M u.....................................................................................................2 2. Mng thng tin di ng 2G......................................................................22.1.Lch s pht trin.................................................................................................2 Cc cng ngh c s dng trong cc h thng in hnh.....................................3 Chuyn giao t mng 2G ln mng 3G.....................................................................3

3. Mng thng tin di ng 3G......................................................................4Lch s pht trin.......................................................................................................5 Cc tiu chun cng ngh in hnh.........................................................................5 Chuyn giao t mng 3G ln mng 4G.....................................................................6

4. Mng thng tin di ng 4G......................................................................7 5. Tng kt....................................................................................................8

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1. M u. Lch s pht trin ca mng thng tin di ng gn lin vi lch s pht trin ca cng ngh. Vic chuyn giao t 2G sang 3G, 3G sang 4G thc cht l vic thay i cng ngh sao cho t c nhng tnh nng hn hn h thng c. Nhng tnh nng l tc truyn ti d liu, kh nng bo mt, kh nng lin kt, dung lng, cht lng ca mng,... V vic c cc h thng 2G, 3G, 4G khc nhau cng ch l do s khc bit v cng ngh m cc h thng s dng. Mng di ng u tin l 1G, l mng s dng cng ngh t bo tng t, mang trong mnh rt nhiu hn ch nh khng c kh nng bo mt, b nh hng bi nhiu, ... V l do ny nn khi cc mng di ng t bo s ra i (t mng 2G tr i) th n nhanh chng b thay th v loi b. Tuy nhin khng phi trong mi th h ca mng thng tin di ng c mt hng pht trin duy nht, m n c hng khc nhau gn lin vi 3 khu vc a l, nhng ni m c trnh khoa hc k thut pht trin l Bc M, Chu u v Nht Bn. Chng ta s h thng ha lch s pht trin ca mng thng tin di ng t 2G n 4G da theo cng ngh m chng s dng trong h thng ca mnh. 2. Mng thng tin di ng 2G. Khc vi mng thng tin di ng 1G s dng cng ngh t bo tng t, th mng thng tin di ng 2G s dng cng ngh t bo s. iu ny lm ci thin cc tnh nng ca h thng. 2.1. Lch s pht trin. H thng thng tin di ng 2G u tin ra i Bc M l D-AMPS (DigitalAdvanced Mobile Phone Service) vi tiu chun l IS-54 (Interim Standard54) v sau ny c ci tin ln l IS-136. H thng s dng tiu chun IS-54 c a vo s dng bt u t nm 1990. n nm 1993, do nhu cu s dng vt qu dung lng ca mng nn tiu chun IS-136 c a ra vi nhng ci tin ph hp nng cao dung lng ca mng. Nm 1991, h thng thng tin di ng 2G th hai c a vo s dng ti Chu u l h thng GSM. Cc tiu chun k thut ca GSM c pht trin t nhng nm 1980 da trn c s ca mt mng di ng c s dng trong mt vi khu vc. Sau n 1982 n c chun ha bi CEPT (European Conference of Postal and Telecommunications Administrations) v to ra Groupe Spcial Mobile (GSM) vi mc ch s dng cho ton Chu u. Vo nm 1989 cng vic qun l tiu chun v pht trin mng GSM c chuyn cho ETSI (European Telecommunications Standards Institute), v cc tiu chun, c tnh phase 1 ca cng ngh GSM c cng b vo nm 1990. Mng in thoi di ng s dng cng ngh GSM c xy dng v a vo s dng u tin bi Radiolinja Phn Lan. Sau ny GSM c i li l Global System for Mobile Communication. Hin nay GSM l h thng thng tin di ng 2G c s dng nhiu nht, chim khong 80% s thu bao. Cng thi gian vi s ra i ca h thng GSM, ti M cc nh nghin cu tm ra mt phng n thng tin di ng s mi da trn cng ngh CDMA2

(c ng dng trc trong qun s) l h thng cdmaOne. Thnh lp nm 1985, Qualcom l nh pht trin cng ngh CDMA cho thng tin di ng, tiu chun u tin ra i l IS-95A. Cc nh cung cp dch v di ng M cung cp dch v mode song song cho php thu bao truy cp vo c hai mng theo tiu chun IS-136 v IS-95. Hin nay h thng cdmaOne s dng tiu chun IS-95A thng tr Bc M v Hn Quc. Nht Bn a ra mt h thng mng 2G s dng tiu chun ring ca mnh l PDC (Personal Digital Cellular) vo 4/1991. PDC c thng mi ha vo 3/1993 v ch c s dng ti nc ny. Ngoi ra cng c rt nhiu h thng s dng cc tiu chun khc cho mng thng tin di ng 2G c s dng nh iDEN, CSD, CDPD ti M,DECT ti Chu u v PHS ti Trung Quc. Tuy nhin cc h thng ny khng ph bin, ng dng trong phm vi hp hoc dng cho cc mng nh (ni ht). 2.2. Cc cng ngh c s dng trong cc h thng in hnh. H thng D-AMPS (vi cc tiu chun IS-54 v IS-136): s dng phng thc truy nhp l TDMA, phng thc iu ch s dng l pi/4-DQPSK. H thng GSM: s dng phng thc truy nhp l TDMA, phng thc iu ch l GMSK. H thng cdmaOne (vi tiu chun IS-95A): s dng phng thc truy nhp l CDMA, phng thc iu ch l QPSK. H thng PDC: s dng phng thc truy nhp l TDMA, phng thc iu ch l pi/4-DQPSK. Bng 1: Cc h thng in hnh ca mng 2G.H thng K thut Phng thc Phm vi v tuyn iu ch Miu t Khc vi IS-54 th IS-136 ghp knh theo thi gian c knh thoi v iu khin

D-AMPS (IS-54 v TDMA pi/4-DQPSK Bc M IS-136) GSM GSM TDMA GMSK CDMA QPSK

Ton cu Trong trng hp FR, tc thoi l 13 kbps, d liu l 9.6 kbps Bc M, Chu , ... IS-95A cung cp tc d liu l 14.4 kbps

cdmaONE IS-95A

PDC

TDMA pi/4-DQPSK Nht Bn Tc d liu l 9.6 kbps

2.3. Chuyn giao t mng 2G ln mng 3G. Qu trnh chuyn giao t h thng thng tin di ng 2G ln 3G khng phi l mt qu trnh chuyn giao ngay lp tc, m n l mt qu trnh din ra t t. Gia 2G v 3G s tri qua mt s h thng trung gian (h thng 2.5G hay 2G tin tin). Cc h thng ny c pht trin trn nn cc h thng 2G thng thng v p dng mt s cng ngh tng tc truyn dn d liu cao hn nhiu so vi h thng 2G. Cc h thng ny gm:3

GSM/GPRS: l mt dch v d liu di ng hng gi trn nn h thng GSM. N c a vo th nghim thng mi nm 2000 v chnh thc thng mi nm 2001. Cc h thng s dng phng thc truy nhp TDMA khc cng hng n vic s dng GPRS nh l k thut tng tc truyn d liu ca mnh. cdmaOne IS-95B: l phin bn dng ng gi ca IS-95A, c th cung cp tc d liu cao gp nhiu ln IS-95A nh vic kt hp cc knh TCH. CDMA2000 1xRTT: song song vi GPRS th 1xRTT cng c pht trin cho cc h thng theo tiu chun IS-95. 1xRTT s dng thm mt knh radio 1.25 MHz nhm nng cao tc cho mng IS-95. 1XRTT c thng mi ha vo nm 2003. y l tiu chun u tin ca CDMA2000 (h thng 3G), tuy nhin n vn ch c xp vo dng h thng 2.5G. EDGE (Enhanced Data Rates for GSM Evolution) : GPRS lm tng tc truyn d liu, tuy nhin vn cha p ng c yu cu ca cc dch v truyn thng a phng tin. GPRS vn s dng phng php iu ch GMSK nn tc cn hn ch. T ngi ta a ra h thng EDGE, s dng k thut iu ch 8PSK. iu ny lm tng tc truyn d liu trong mng GPRS ln 2 n 3 ln. EDGE bt u c thng mi ha vo nm 2003 ti M. Bng 2: Cc h thng trung gian gia 2G v 3G.H thng K thut Phng v tuyn thc iu ch TDMA GMSK Miu t

GSM/GPRS (cc h thng TDMA khc cng hng ti vic dng GPRS) cdmaONE IS-95B

S dng k thut chuyn mch gi thay v chuyn mch knh nh GSM thng thng nng cao tc d liu ln ti 56-114 kbps Khc vi IS-95A th bng vic kt hp cc knh lu lng IS-95B c th nng cao tc d liu ln n 115.2 kbps L tiu chun u tin ca CDMA2000, s dng mt cp knh tn s 1.25 Mhz, tc d liu t c l 144 kbps Tc d liu ln ti 384 kbps nh thay i phng php iu ch sang 8PSK

CDMA

QPSK

CDMA2000 1xRTT

CDMA

QPSK

GSM/EDGE

TDMA

8PSK

3. Mng thng tin di ng 3G. Nhn thc r v tm quan trng ca thng tin di ng nn khi h thng thng tin di ng 2G vn cn ang c chun ha th c mt s ni nghin cu v h thng thng tin di ng 3G. Nhng cng ngh mi c p dng nhm ci thin tnh nng ca h thng thng tin di ng. Tuy c nhiu xut h thng c a ra, nhng ITU ch cng nhn nhng h thng tha mn cc yu cu v k thut ca mnh mi c gi l 3G.4

3.1. Lch s pht trin. H thng 3G u tin c a ra l UMTS vo nm 2001 c tiu chun bi 3GPP. UMTS c s dng u tin Chu u sau lan ra ton th gii nh ti Nht Bn, Trung Quc, ... H thng UMTS c xy dng nhm mc ch k tha h thng GSM (pht trin t h thng GSM/GPRS/EDGE hin ti) nn n c kh nng phc v c h thng GSM. Bn cnh h thng UMTS pht trin t h thng GSM, h thng CDMA2000 c a ra bi 3GPP2, chia s nn tng vi h thng IS-95 ca 2G. CDMA2000 c a vo s dng bt u t 2002, v c bit pht trin ti Bc M v Hn Quc (phin bn s dng l CDMA2000 1xEV-DO Release 0). Nm 2005, IEEE cng b tiu chun 802.16e cho WiMAX v gi l Mobile WiMAX. Mobile WiMAX c ci tin so vi cc chun WiMAX trc l h tr vic truyn d liu trong khi di chuyn. 3.2. Cc tiu chun cng ngh in hnh. ITU a ra 6 tiu chun cng ngh cho giao din truy nhp v tuyn ca thnh phn mt t ca cc h thng IMT-2000 (3G). Cc tiu chun y bao gm: IMT-2000 CDMA Direct Spread (thng c bit n l W-CDMA hay UMTS/FDD): l cng ngh c ng dng trong h thng UMTS, chim th phn ln nht trong h thng thng tin di ng ton cu. IMT-2000 CDMA Multi-Carrier (hay c bit n l CDMA2000): l cng ngh pht trin ln 3G ca cdmaOne, cnh tranh trc tip vi cng ngh WCDMA. CDMA2000 c rt nhiu phin bn khc nhau nh CDMA2000 EVDV, CDMA2000 EV-DO, ... Phin bn c s dng nhiu nht l CDMA2000 EV-DO. IMT-2000 CDMA TDD: h cng ngh CDMA TDD bao gm TD-CDMA (UMTS-TDD) v TD-SCDMA. TD-CDMA ch yu dng truy nhp internet bng thng rng ch khng dnh cho thoi, cng ngh ny hin nay c trin khai hn ch ti mt s nc. Cn cng ngh TD-SCDMA c Trung Quc ang nghin cu v ch trin khai ti Trung Quc. IMT-2000 TDMA Single-Carrier: c pht trin t tiu chun IS-136 (h thng D-AMPS). Vn ang trong giai on pht trin nn t c kh nng chim lnh c th trng thng mi. IMT-2000 FDMA/TDMA: c tn gi l DECT do ETSI pht trin v c trin khai mt s nc Chu u v Chu . Tuy nhin do vng ph sng nh nn ch ng dng cho cc h thng nh c quan, ni ht, khng thch hp cho mng ph sng ton quc. IMT-2000 OFDMA TDD WMAN: da trn tiu chun 802.16e-2005 ca IEEE, hay cn c gi l mobile WiMAX (hay l WinMAX di ng). Cng ngh WiMAX (Worldwide Interoperability for Microwave Access) c pht trin mi hon ton nn khng tng thch vi bt k cng ngh no trc , hn na WiMAX c pht trin ch yu cho cc dch v d liu bng rng nn vic s dng dch v thoi trn WiMAX kh tn km. Ngoi ra tn s s5

dng cng l mt vn cho WinMAX, nhng iu trn khin cho WinMAX di ng khng c s dng ph bin nh W-CDMA. Bng 3: Cc h thng 3G in hnh.H thng UMTS Tiu chun k thut IMT-2000 CDMA DS K thut v tuyn W-CDMA Phm vi Ton cu Miu t rng bng tn l 5 MHZ (so vi CDMA bng hp ca M l 1.25 Mhz), tc truyn d liu t 384 kbps, cn nu h tr HSDPA th tc ng xung l thuyt c th ln ti 21 Mbps Ch yu dng cho internet bng thng rng ch khng dnh cho thoi

IMT-2000 CDMA TDD

TD-CDMA

Chu u

TD-SCDMA Trung Quc c pht trin v ng dng ch ti Trung Quc CDMA2000 IMT-2000 1xEV-DO CDMA MC Release 0 Mobile WiMAX (802.16e) CDMA Ton cu Tc d liu ng xung l 2.45 Mbps, ng ln l 0.15 Mbps Tc ln ti 128 Mbps cho ng xung v 56 Mbps cho ng ln

IMT-2000 OFDMA OFDMA TDD WMAN

Ton cu

3.3. Chuyn giao t mng 3G ln mng 4G. Ging nh vic chuyn giao t 2G ln 3G th vic chuyn giao t 3G ln 4G cng din ra t t, nh mt s cng ngh th tc truyn d liu c nng dn ln v dn dn t c tiu chun cho 4G. Vic xy dng 4G cng phi c pht trin trn nn 3G ch khng phi thay th hon ton 3G. Cc cng ngh trn s c gi l cng ngh pre 4G, gm c: HSPA, HSPA+, LTE, CDMA2000 1xEV-DO Revision A, Revision B. HSPA v HSPA+: HSPA l s hp nht ca 2 cng ngh HSDPA v HSUPA nhm ci thin hiu sut truyn d liu cho W-CDMA, HSDPA c gii thiu vo nm 2002, HSUPA c gii thiu vo nm 2004. HSPA+ c a ra vo nm 2008 l phin bn nng cp ca HSPA, gip nng tc truyn d liu ln gp nhiu ln so vi HSPA, tuy nhin vn cha t ti tc ca 4G. LTE: l h thng c xy dng trn nn tng GSM/EDGE v UMTS/HSPA, c a vo thng mi u tin 12/2009. CDMA2000 1xEV-DO Revision A,B: l cc tiu chun k tha ca CDMA2000 1xEV-DO Release 0 c pht trin t h thng CDMA2000 1xRTT (trc l IS-95). Nm 2009 th Rev. C ra i (gi l UMB), l cng ngh snh ngang vi LTE ca HSPA/WCDMA.

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Bng 4: Cc h thng trung gian gia 3G v 4G.H thng HSPA v HSPA+ LTE H thng nn tng W-CDMA Miu t S dng truyn dn thch ng, iu ch bc cao 16QAM/64QAM v anten MIMO nng cao tc d liu ca mng

GSM/EDGE v S dng k thut OFDMA/xung v SC-FDMA/ln kt hp vi UMTS/HSPA anten MIMO, gip h thng t c tc 100 Mbps cho ng xung v 50 Mbps cho ng ln Rev.A thm mt s giao thc trn nn Release 0 tng tc d liu. Rev.A gii thiu mt s tc chuyn tip lin kt d liu mi, cng nh giao thc lm gim thi gian thit lp kt ni. Rev.B li l s tin ha a sng mang ca Rev.A

CDMA200 CDMA2000 0 1xEV1xEV-DO DO Release 0 Revision A,B

4. Mng thng tin di ng 4G. Cc ng dng a phng tin ngy nay cng ngy cng i hi tc truyn d liu cao hn, v vy vic nng cao tc truyn d liu trong cc h thng thng tin di ng l mt nhu cu tt yu. Cc hng hot ng trong lnh vc thng tin di ng nghin cu nhiu cng ngh v tuyn b rng cng ngh ca mnh l 4G. Tuy nhin ITU a ra nh ngha th no l 4G nn ch c mt s h thng tha mn cc yu cu v c gi l h thng 4G. LTE-Advanced (IMT-Advanced): l mt tiu chun c pht trin bi 3GPP v c a ra nm 2011. Nn tng ca h thng ny l LTE , h thng LTE mc d nng tc truyn d liu ln rt cao nhng vn cha t ti 1Gbps nh yu cu ca ITU, ch khi LTE-Advanced ra i mi tha mn iu kin ny. WiMAX 2(802.16m): c giao din v tuyn nng cao vi tc 100Mbps khi di ng v 1Gbps khi ng yn. WiMAX 2 s c a ra thng mi vo nm 2012. Bng 5: Cc h thng 4G.H thng H thng nn tng Miu t LTE-Advanced c rng di tn ln hn so vi LTE (c th ln n 100 Mhz so vi 20 Mhz), LTE-Advanced cng s dng s anten MIMO nhiu hn v mt s cng ngh nh truyn dn a im phi hp, dng cc b lp v b chuyn tip, ...Tt c nhng cng ngh trn gip cho tr gim so vi LTE v tc truyn cao hn LTE (tha mn yu cu tc ti a l 1Gbps khi ng yn) WiMAX 2 t c tc cao hn bng cch s dng anten thng minh v phng php tip cn a knh

LTELTE Advanced

WiMAX 2 WiMAX (802.16m)

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5. Tng kt. Ta c th tng kt qu trnh pht trin cc h thng ch yu ca mng thng tin di ng t 2G ln 4G qua bng sau: Bng 6: Cc h thng trong cc mng thng tin di ng t 2G ln 4G.2G PDC AMPS 3GPP 3GPP2 PDC D-AMPS GSM cdmaONE cdmaONE (IS-95A) (IS-95B) GPRS CDMA200 1xRTT EDGE Trung gian gia 2G v 3G 3G UMTS/WCDMA HSPA HSPA+ LTE LTEAdvanced Trung gian gia 3G v 4G 4G

CDMA2000 CDMA2000 CDMA2000 1xRTT 1xEV-DO 1xEV-DO Release 0 Revision A,B,C (Rev.C hay l UMB) Mobile WiMAX (802.16e) WiMAX 2 (802.16m)

IEEE

Cc dng cng ngh khc

IDEN, CSD, DECT, PHS, CDPD

WiDEN, HSCSD

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