S pht trin nhanh chng ca dch v s liu m IP t ra cc yu mi i vi cng ngh vin thng di ng. Thng tin di ng th h 2 mc d s dng cng ngh s nhng l h thng bng hp v c xy dng trn c ch chuyn mch knh nn khng th p ng c dch v mi ny. 3G (third-generation) cng ngh truyn thng th h th ba l giai on mi nht trong s tin ha ca ngnh vin thng di ng. Nu 1G (the first gerneration) ca in thoi di ng l nhng thit b analog, ch c kh nng truyn thoi. 2G (the second generation) ca TD gm c hai cng nng truyn thoi v d liu gii hn da trn k thut s. Trong bi cnh ITU a ra n tiu chun ha h thng thng tin di ng th h th 3 vi tn gi IMT 2000. IMT 2000 m rng ng k kh nng cung cp dch v v cho php s dng nhiu phng tin thng tin. Mc ch ca IMT 2000 l a ra nhiu kh nng mi nhng cng ng thi m bo s pht trin lin tc ca h thng thng tin di ng th h th hai (2G) vo nhng nm 2000. 3G mang li cho ngi dng cc dch v gi tr gia tng cao cp, gip chng ta thc hin truyn thng thoi v d liu (nh e-mail v tin nhn dng vn bn), download m thanh v hnh nh vi bng tn cao. Cc ng dng 3G thng dng gm hi ngh video di ng; chp v gi nh k thut s nh in thoi my nh; gi v nhn e-mail v file nh km dung lng ln; ti tp tin video v MP3; thay cho modem kt ni n my tnh xch tay hay PDA v nhn tin dng ch vi cht lng cao2. Th no l cng ngh 3G3G l thut ng dng ch cc h thng thng tin di ng th h th 3 (Third Generation). c rt nhiu ngi nhm ln mt cch v hoc hu gia hai khi nim 3G v UMTS (Universal Mobile Telecommunications Systems). hiu th no l cng ngh 3G, chng ta hy xt qua i nt v lch s pht trin ca cc h thng in thoi di ng. Mc d cc h thng thng tin di ng th nghim u tin c s dng vo nhng nm 1930-1940 trong trong cc s cnh st Hoa K nhng cc h thng in thoi di ng thng mi thc s ch ra i vo khong cui nhng nm 1970 u nhng nm 1980. Cc h thng in thoi th h u s dng cng ngh tng t v ngi ta gi cc h thng in thoi k trn l cc h thng 1G. Khi s lng cc thu bao trong mng tng ln, ngi ta thy cn phi c bin php nng cao dung lng ca mng, cht lng cc cuc m thoi cng nh cung cp thm mt s dch v b sung cho mng. gii quyt vn ny ngi ta ngh n vic s ho cc h thng in thoi di ng, v iu ny dn ti s ra i ca cc h thng in thoi di ng th h 2. chu u, vo nm 1982 t chc cc nh cung cp dch v vin thng chu u (CEPT Confrence Europene de Postes et Telcommunications) thng nht thnh lp mt nhm nghin cu c bit gi l Groupe Spciale Mobile (GSM) c nhim v xy dng b cc ch tiu k thut cho mng in thoi di ng ton chu u hot ng di tn 900 MHz. Nhm nghin cu xem xt nhiu gii php khc nhau v cui cng i n thng nht s dng k thut a truy nhp phn chia theo m bng hp (Narrow Band TDMA). Nm 1988 phin bn d tho u tin ca GSM c hon thnh v h thng GSM u tin c trin khai vo khong nm 1991. K t khi ra i, cc h thng thng tin di ng GSM pht trin vi mt tc ht sc nhanh chng, c mt 140 quc gia v c s thu bao ln ti gn 1 t. Lc ny thut ng GSM c mt ngha mi l h thng thng tin di ng ton cu (Global System Mobile). Cng trong thi gian k trn, M cc h thng in thoi tng t th h th nht AMPS c pht trin thnh cc h thng in thoi di ng s th h 2 tun th tiu chun ca hip hi vin thng M IS-136. Khi cng ngh CDMA (Code Division Multiple Access IS-95) ra i, cc nh cung cp dch v in thoi di ng M cung cp dch v mode song song, cho php thu bao c th truy cp vo c hai mng IS-136 v IS-95.Do nhn thc r v tm quan trng ca cc h thng thng tin di ng m Chu u, ngay khi qu trnh tiu chun ho GSM cha kt thc ngi ta tin hnh d n nghin cu RACE 1043 vi mc ch chnh l xc nh cc dch v v cng ngh cho h thng thng tin di ng th h th 3 cho nm 2000. H thng 3G - L h thng thng tin di ng ton cu cho cc loi hnh thng tin v tuyn:+ Tch hp cc mng thng tin hu tuyn v v tuyn + Tng tc cho mi loi dch v vin thng t c nh, di ng, thoi, d liu, Internet n cc dch v a phng tin- C th h tr cc dch v nh:+ Cc phng tin ti nh o trn c s mng thng minh, di ng cc nhn v chuyn mng ton cu+ m bo chuyn mng quc t cho php ngi dng c th di chuyn n bt k quc gia no cng c th s dng mt s in thoi duy nht. + m bo cc dch v a phng tin ng thi cho ting, s liu chuyn mch knh v s liu chuyn mch gi.- D dng h tr cc dch v mi xut hin.Mi trng hot ng ca IMT 2000 c chia thnh 4 vng vi tc bit R nh sau:+ Vng 1: Trong nh, pico, Rb 2 Mbit/s+ Vng 2: thnh ph, macr, R b 384 kbit/s+ Vng 2: ngoi , macr, Rb 144 kbit/s+ Vng 4: ton cu, Rb = 9,6 kbit/s. IMT-2000 c nhng c im chnh: 3.1 Tnh linh hot:Vi s lng ln cc v sp nhp v hp nht trong ngnh cng nghip in thoi di ng v kh nng a dch v ra th trng ngoi nc, nh khai thc khng mun phi h tr giao din v cng ngh khc. iu ny chc chn s cn tr s pht trin ca 3G trn ton th gii. IMT-2000 h tr vn ny, bng cch cung cp h thng c tnh linh hot cao, c kh nng h tr hng lot cc dch v v ng dng cao cp. IMT-2000 hp nht 5 k thut (IMT-DS, IMT-MC, TMT-TC, IMT-SC, IMT-FT) v giao tip sng da trn ba cng ngh truy cp khc nhau (FDMA - a truy cp phn chia theo tn s, TDMA - a truy cp phn chia theo thi gian v CDMA - a truy cp phn chia theo m). Dch v gia tng trn ton th gii v pht trin ng dng trn tiu chun duy nht vi 5 k thut v 3 cng ngh.3.2. Tnh kinh t:S hp nht gia cc ngnh cng nghip 3G l bc quan trng quyt nh gia tng s lng ngi dng v cc nh khai thc. .3.3. Tnh tng thch:Cc dch v trn IMT-2000 c kh nng tng thch vi cc h thng hin c. Chng hn, mng 2G chun GSM s tip tc tn ti mt thi gian na v kh nng tng thch vi cc h thng ny phi c m bo hiu qu v lin mch qua cc bc chuyn. 3.4. Thit k theo modul:Chin lc ca IMT-2000 l phi c kh nng m rng d dng pht trin s lng ngi dng, vng ph sng, dch v mi vi khon u t ban u thp nht.Phn loi cc dch v ca IMT-2000

KiuPhn loiDch v chi tit

Dch v di ngDch v di ng- Di ng u cui/di ng c nhn/di ng dch v

Dch v thng tin nh v- Theo di di ng/theo di di ng thng minh

Dch v vin thngDch v m thanh- Dch v m thanh cht lng cao(16 64 kbit/s)- Dch v m thanh AM (32 64 kbit/s)- Dch v truyn thanh FM (64 384kbit/s)

Dch v s liu- Dch v s liu tc trung bnh (64 144 kbit/s)- Dch v s liu tc tng i cao (144 2 Mbit/s)- Dch v s liu tc cao ( 2Mbit/s)

Dch v a phng tin- Dch v Video (384kbit/s)- Dch v hnh chuyn ng (384kbit/s - 2Mbit/s)- Dch v hnh chuyn ng thi gian thc ( 2Mbit/s)

Dch v InternetDch v Internet n gin- Dch v truy nhp Web (384kbit/s - 2Mbit/s)

Dch v Internet thi gian thc- Dch v Internet (384kbit/s - 2Mbit/s)

Dch v internet a phng tin- Dch v Website a phng tin thi gian thc ( 2Mbit/s)

4. L trnh pht trin t cc h thng th h hai n th h 3 4.1. Lch trnh nghin cu pht trin h thng thng tin di ng th h ba.Cng trnh nghin cu ca cc nc Chu u cho W-CDMA bt u t cc n CDMT (Code Division Multiple Testbed): Phng th nghim a truy nhp theo m) v FRAMES (Future Radio Multiple Access Scheme: S a truy nhp v tuyn tng lai) t u thp nin 90. Cc d n ny cng tin hnh thc nghim cc h thng W-CDMA nh gi cht lng ng truyn. Cng tc tiu chun ho chi tit c thc hin 3GPP. Lch trnh trin khai W-CDMA c cho hnh v.Mc d mng cdma One (IS-95) khng phi l cc mng u tin cung cp truy nhp s liu, nhng y l cc mng c thit k duy nht truyn s liu . Trc ht chng x l truyn dn s liu v ting theo cch rt ging nhau. kh nng truyn dn tc thay i c sn trong cdmaOne cho php quyt nh lng thng tin cn pht, v th cho php ch s dng tim nng mng theo nhu cu. V cc h thng cdmaOne s dng truyn ting ng gi trn ng trc (cc ng truyn dn t BTS n MSC), nn kh nng truyn s liu gi c sn trong thit b. Cng ngh truyn dn s liu gi ca cdmaOne s dng ngn xp giao thc s liu gi s t ong (CDPD: Cellular Digital Packet Data) ph hp vi TCP/IP. B sung truyn s liu vo mng cdma2000 s cho php nh khai thc mng tip tc s dng cc phng tin truyn dn, cc phng tin v tuyn, c s h tng v cc thit bi u cui hin c bng cch nng cp phn mm cho chc nng tng tc. Nng cp ln IS-95B cho php tng tc knh cung cp tc s liu 64 115 kbit/s v ng thi ci thin chuyn giao mm v chuyn giao cng gia cc tn s. Cc nh sn xut cng b cc kh nng s liu gi, s liu knh v fax s trn cc thit b cdmaOne ca h. Mt trong cc mc tiu quan trng ca ITU IMT 2000 l to ra cc tiu chun khuyn khch s dng mt bng tn trn ton cu nhm thc y mc cao vic nhiu ngi thit k v h tr cc dch v cao. IMT 2000 s s dng cc u cui b ti kch c nh, m rng nhiu phng tin khai thc v trin khai cu trc m cho php a ra cc cng ngh mi. Ngoi ra cc h thng 3G ha hn em li cc dch v ting v tuyn c cc mc cht lng hu tuyn ng thi vi tc v dung lng cn thit h tr a phng tin v cc ng dng tc cao. Cc dch v trn c s nh v, o hng, h tr cp bo v cc dch v tin tin khc cng s c h tr. S pht trin ca h thng 3G s m cnh ca cho mch vng thu bao v tuyn i vi PSTN v truy nhp mng s liu cng cng, ng thi m bo iu kin tin li hn cc ng dng v cc tim nng mng. N cng s m bo chuyn mng ton cu, di ng dch v, ID trn c s vng, tnh cc v truy nhp th mc ton cu. Thm ch c th hy vng cng ngh 3G cho php kt ni mng v tinh mt cch lin tc. Mt trong cc yu cu k thut ca cdma2000l tng thch vi h thng c cdmaOne v: Cc dch v ting, cc b m ho ting, cc cu trc bo hiu v kh nng bo mt.Bng cch chuyn t cng ngh giao din v tuyn IS-95CDMA hin nay sang IS-2000 1X ca tiu chun cdma2000, cc nh khai thc t c tng dung lng v tuyn gp i v c kh nng x l s liu gi n 144 kbit/s. Cng s ra i ca cdma2000 giai on mt, cc dch v s liu cng s c ci thin. Giai on 2 cng s uc hnh thnh c cu MAC (Medium Access Control: iu khin truy nhp mi trng) v nh ngha giao thc on ni v tuyn (RLP: Radio Link Prtcol) cho s liu gi h tr cc tc s liu gi t nht l 144kbit/s.Thc hin giai on 2 ca cdma2000s mang li rt nhiu cc kh nng mi v cc tng cng dch v. Giai on 2 s h tr tt c cc kch c knh (6X, 9X v 12X) c cu cho cc dch v ting, b m ho ting cho cdma2000, bao gm ting trn nn IP. Vi giai on 2 cc dch v a phng tin thc s s c cung cp v s mang li c hi thun li b sung cho cc nh khai thc. Cc dch v a phng tin s c th thc hin c thng qua MAC s liu gi, h tr y cho s liu gi, h tr y cho dch v s liu gi n 2Mb/s, RLP h tr tt c cc tc s liu n 2Mb/s v m hnh gi a phng tin tin tin.

L trnh pht trin t cdmaOne n cdma 2000

C cdma2000 giai on 1 v 2 u c th ho trn vi cdmaOne s dng hiu qu nht ph tn tu theo nhu cu ca khch hng. Chng hn mt nh khai thc c nhu cu ln v dch v s liu tc c th chn trin khai kt hp giao on 1 cdma2000 v cdmaOne vi s dng nhiu knh hn cho cdmaOne. mt th trmg khc, ngi s dng c th cha cn nhanh chng s dng cc dch v tc s liu cao th nhiu knh hn s c dnh cho cc dch v ca cdmaOne. V cc kh nng ca cdma2000 giai on hai sn sng nn nh khai thc khc c nhiu cch la chn hn trong vic s dng ph tn h tr cc dch v mi4.3. Tng kt qu trnh pht trin ca h thng thng tin di ng n th h baTrong qua trnh ny ta tng kt nn tng cng ngh chnh ca thng tin di ng t th h mt n th h ba v qu trnh pht trin ca cc nn tng ny n nn tng ca th h ba. tin ti th h ba c th th h hai phi tri qua mt giai on trung gian, giai on ny gi l th h 2,5.

Tng kt qu trnh pht trin ca cc nn tng thng tin di ng th h 1 n th h 35. Cc tiu chun cng ngh ca h thng thng tin di ng th h ba:Cc h thng thng tin di ng th hai gm: GSM, IS 136, IS 95 CDMA v PDC. Trong qa trnh thit k cc h thng thng tin di ng th h ba, cc h thng th h hai c cc c quan tiu chun ho ca tng vng xem xt a ra cc xut tng thch. Khuyn ngh ITU-R M.1457 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 (tn gi mng 3G ca ITU), bao gm:- IMT-2000 CDMA Direct Spread (tri ph trc tip), thng c bit di tn WCDMA. - IMT-2000 CDMA Multi-Carrier (nhiu sng mang), y l phin bn 3G ca h thng IS-95 (hin nay gi l cdmaOne) - IMT-2000 CDMA TDD- IMT-2000 TDMA Single-Carrier (mt sng mang), cc h thng thuc nhm ny c pht trin t cc h thng GSM hin c ln GSM 2+ (c gi l EDGE). - IMT-2000 FDMA/TDMA (thi gian tn s), y l h thng cc thit b ko di thu bao s chu u.