Tong Hop 3G

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    24-Dec-2015

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3g

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Bang TanPhn b bng tn 3G ti Vit nam.Cc mng 3G Vit nam mnh hin dng cng ngh truy nhp v tuyn l W-CDMA. W-CDMA th c hai loi l Frequency Division Duplex (FDD) Time Division Duplex. FDD v TDD khc nhau nh th no?FDD: dng ring 5MHz bng thp cho ng Uplink v 5MHz bng cao cho ng Downlink. TDD: ch tn mt bng tn 5MHz phn chia theo thi gian cho c Uplink v DownlinkHin cc nh mng 3G Vit nam chia nhau bng tn IMT-2000, vy bng IMT-2000 l bng tn no?Bng tn IMT-2000Bng tn IMT-2000 cc nh mng Vit nam mnh ang chia nhau nm t 1920 MHz n 1980 MHz cho hng Uplink v 2110 MHz n 2170 MHz cho hng Downlink. Nh vy c tng cng 60MHz, chia cho 4 giy php 3G ca Viettel, Mobifone, Vinaphone, EVN Telecom + Vietnammobile mi giy php s c 15MHz cho mi hng, tc mi mng c 3 sng mang 5MHz trin khai 3G. C th nh sau:- Mobifone: s dng bng tn 1920 MHz 1935 MHz cho UL v 2110 MHz 2125 MHz cho DL- Viettel: s dng bng tn 1935 MHz 1950 MHz cho UL v 2125 MHz 2140 MHz cho DL- Vinaphone: s dng bng tn 1950 MHz 1965 MHz cho UL v 2140 MHz 2155 MHz cho DL- EVN Telecom v Vietnammobile chia s bng tn 1965 MHz 1980 MHz cho UL v 2155 MHz 2170 MHz cho DLCc nh mng c th s dng mt sng mang cho cc dch v R99 nh thoi, R99 PS, mt sng mang dng cho HSDPA, mt sng mang dnh. Hoc thu bao t qu th ch cn dng mt sng mang cho c R99 ln HSPA v dnh 2 sng mang cng khng saoGn y c chuyn Vietnammobile ku ca rng nu EVN Telecom v vi Viettel th Vietnammobile mt bng tn 3G, rng vi na bng tn th Vietnammobile khng th s dng Thc ra, c chia cho h mt sng mang 5 MHz cng lm nn chuyn ri, nu h thc s mun lm

Cau Truc Mang 3GUMTS Network Architecture (Rel'99)UE (User Equipment).Thit b ngi s dng thc hin chc nng giao tip ngi s dng vi hthng, UE gm hai phn:ME (Mobile Equipment): L u cui v tuyn c s dng cho thngtin v tuyn trn giao din Uu.USIM (UMTS Subscriber Identity): L mt th thng minh cha thng tinnhn dng ca thu bao, n thc hin cc thut ton nhn thc, lu gi cc kha nhn thc v mt s thng tin thu bao cn thit cho u cuiUTRAN (Universal Terrestrial Radio Access Network).Mng truy nhp v tuyn c nhim v thc hin cc chc nng lin quan ntruy nhp v tuyn, UTRAN gm:Node B: Thc hin chuyn i dng s liu gia cc giao din Iub v Uu.N cng tham gia qun l ti nguyn v tuyn.RNC: C chc nng s hu v iu khin cc ti nguyn v tuyn trongvng. RNC cn l im truy cp tt c cc dch v do UTRAN cung cp cho mngli CN, chng hn qun l tt c cc kt ni n UE.CN (Core Network).HLR: L thanh ghi nh v thng tr lu gi thng tin chnh v l lchdch v ca ngi s dng. Cc thng tin ny bao gm: Thng tin v cc dch vc php, cc vng khng c chuyn mng v cc thng tin v dch v b sungnh: trng thi chuyn hng cuc gi, s ln chuyn hng cuc gi.MSC/VLR: L tng i (MSC) v c s d liu (VLR) cung cp ccdch v chuyn mch knh cho UE ti v tr ca n. MSC c chc nng s dng ccgiao dch chuyn mch knh (CS). VLR c chc nng lu gi bn sao v l lchngi s dng cng nh v tr chnh xc ca UE trong h thng ang phc v.GMSC: Chuyn mch kt ni vi mng ngoi.SGSN: C chc nng nh MSC/VLR nhng c s dng cho cc dchv chuyn mch gi (PS).GGSN: C chc nng nh GMSC nhng ch phc v cho cc dch vchuyn mch g

Xu ly tin hieu 3GTH TC X L CA H THNG 3GChng ta xt qu trnh x l tn hiu lp vt l nh sau:Pha pht:(1) D liu ca ngi dng (b/s) c m ha (channel coding) bng cc phng tin nh turbo code, convolution code, interleaving. Mc ch l FEC (Forward Error Correction), gip pha thu tng kh nng sa li. (1/2 hoc 1/3)(2) D liu sau m ha s c iu ch bng gc (Base Band Modulation) bng cc phng php nh BPSK, QPSK, 16QAM > Mt symbol sau iu ch cng c s lng bit nhiu hn. Mc ch ca iu ch l g?iu ch l dng tn hiu cn truyn lm thay i mt thng s no ca mt tn hiu khc, tn hiu ny thc hin nhim v mang tn hiu cn truyn n ni thu nn c gi l sng mang (carrier wave). Mc ch ca s iu ch l di ph tn ca tn hiu cn truyn n mt vng ph tn khc thch hp vi tnh cht ca ng truyn v nht l c th truyn ng thi nhiu knh cng mt lc (a hp phn tn s).(3) Tn hiu sau iu ch (vn bng gc s/s symbol per second) s c tri ph (Spectrum spreading) (c/s chip per second). Mc ch ca tri ph l g?(4) Tn hiu sau tri ph c gi ngu nhin (scrambling) vi cng tc chip (3840000 chips/s)(5) Sau scrambling, tn hiu mi c iu ch ln cao tn (RF modulation) (v d di 1920-1980 MHZ / 2110-2170 MHZ).(6) Sau iu ch cao tn, tn hiu cao tn c a ra anten, pht iPha thu:(1) Thu tn hiu cao tn, gii iu ch cao tn ly tn hiu bng gc(2) Gii ngu nhin (descrabling)(3) Despreading(4) Baseband demodulation(5) Decoding/Deinterleaving thu li tn hiu ban u m pha pht mun gi cho pha thu.Vy, khng c tri ph pha cao tn no c.* Gii thchBit, Symbol, ChipBit : l d liu sau qu trnh m ha ti nguynSymbol : D liu sau qu trnh m ha knh v an xen( channel coding and interleaving)Chip : D liu sau qu trnh tri phSource coding: C th tng hiu qu truyn tiChannel coding : C th lm cho vic truyn ti ng tin cy hnSpeading lm tng kh nng "gim nhiu"Thng qua iu ch, cc tn hiu s chuyn tn hiu v tuyn t cc tn hiu s.V. Spreading TechnologyTri ph c ngha l tng bng thng ca tn hiu ngoi bng thng thng cn thit thch ng vi thng tin. Qu trnh tri ph trong UTRAN bao gm hai hot ng ring bit: channelization v scrambling.Cc hot ng u tin l hot ng channelization,bin i tt c cc d liu vo mt s chip, do tng bng thng ca tn hiu. S lng chip mi d liu c gi l Spreading Factor (SF). M channelization m s trc giao, c ngha rng trong mi trng l tng, chng khng nh hng ln nhau.Cc hot ng th hai l hot ng Scrambling. Scrambling khng thay i bng thng tn hiu nhng ch lm cho cc tn hiu t cc ngun khc nhau tch ri nhau. Khi tc chip l t c trong channelization, tc chip l khng b nh hng bi cc ScramblingSF = chip rate / symbol rate1. Mc ch ca Channelization CodeM Channelization c s dng phn bit cc knh vt l khc nhau ca mt my phti vi ng xung, M channelization (OVSF code) c s dng tch cc knh vt l khc nhau ca mt Celli vi ng ln, M channelization (OVSF code) c s dng tch cc knh vt l khc nhau ca mt trong UEOrthogonal Variable Spreading Factor (OVSF)i vi dch v thoi (AMR), ng xung SF l 128, c ngha l c 128 dch v thoi ti a c th c h tr trong mt nh cung cp dch v WCDMA;in thoi Video (64k d liu gi) dch v, ng xung SF l 32, c ngha l c 32 dch v thoi ti a c th c h tr trong mt nh cung cp dch v WCDMA2. Purpose of Scrambling CodeM Scrambling c s dng phn bit cc my pht khc nhaui vi ng xung, m Scrambling c s dng Cell ring bit khc nhau trong mt sng mangi vi ng ln, m Scrambling c s dng tch UE khc nhau trong mt sng mang

Cac KenhLogical channels, Transport channels, Physical channels in WCDMA~~~~~~~~~~~~~~~Logical~~~~~~~~~~~~~~~~~Logical channels c nh ngha trn giao tip gia 2 sublayer ca lp 2 l RLC v MAC. Do vy, Logical channels ch yu da trn BN CHT/LOI THNG TIN: traffic hay control? (WHAT TO); Dedicated hay common? (HOW TO)Phn loi logical channels:1. control logical channels_____a. BCCH (Broadcast Control Channel): qung b system information (vd cell ID, code sequence, timers..)_____b. PCCH (Paging Control Channel): thng bo tm gi n UE_____c. DCCH (Dedicated Control Channel): chuyn thng tin bo hiu (signal information) n mt UE c th, trong trng hp UE ny thit lp c RRC connection. y chnh l SRB_____d. CCCH (Common Control Channel): chuyn thng tin bo hiu (signal information) n mt UE c th, trong trng hp UE ny cha c RRC connection.2. traffic logical channels:_____a. DTCH (Dedicated Traffic Channel): mang UE traffic, cho mt UE c th no ._____b. CTCH (Common Traffic Channel): mang UE traffic, n mt nhm nhiu UE (vd, SMS qung b)~~~~~~~~~~~~~~~Transport~~~~~~~~~~~~~~~~Transport channels c nh ngha trn giao tip gia lp 2 v lp 1, MAC v PHY. Transport channels khng quan tm n ni dung ca ca thng tin (traffic hay control) m quan tm n cc c tnh k thut cn c trn ti nguyn v tuyn ( lp 1) nh channel coding (turbo hay convolutional), interleaving hay khng interleaving, tri ph vi SF bao nhiu nhm m bo cc ch tiu cht lng ca cc loi knh logical bn trn (tng ng vi cc dch v c QoS khc nhau)Cc knh transport c phn thnh 2 loi: dedicated v common. (HOW TO).1. Dedicated, ch c mt transport dedicated channel m thiDCH (Dedicated Channel): DCH mang hoc traffic hoc control t logical channels. Trong trng hp mt dch v n l th s c 02 knh DCH c thit lp, mt DCH mang DTCH v DCH cn li mang DCCH (SRB). Mi knh DCH c th dng truyn ti 4 knh DCCH (SRB) V mi UE s dng 01 DCH cho hng xung v 01 DCH cho hng ln.2. Common_____a. BCH (Broadcast Channel): ch c downlink, truyn ti cho BCCH (mang SIB). BCH l knh c tc c nh, thp (bao nhiu?) nhng cn pht mc cng sut cao cho mi UE trong cell c th decode c SIB/MIB._____b. PCH (Paging Channel): ch c downlink, truyn ti cho PCCH (mang thng tin tm gi v cc thng bo notification ca network n tng UE ring r.)____c. RACH (Random Access Channel): ch c uplink. L knh c yu cu thp v mt cht lng (cng sut pht thp nht c th gim nhiu), truyn cc packets ngn khng rng buc v delay hoc cc thng tin bo hiu trong qu trnh UE khi to truy nhp h thng.Knh RACH c nhiu tc truyn dn khc nhau._____d. FACH (Forward Access Channel): ch c downlink. C nhiu bit rate khc nhau (bao nhiu?)_____e. HS-DSCH (High Speed Downlink Shared Channel): dng cho HSDPANhiu transport channels khc nhau c th ghp chung, to thnh CCTrCH (Coded Composite Transport Channel), v s dng cng ti nguyn vt l (physical resources), c lp vt l coi nh mt knh transport n l.Cc knh transport nh CPCH (Common Packet Channel) v DSCH (Downlink Shared Channel) hin khng cn dng na.Khc vi GSM khng c khi nim transport channel, trong UMTS transport channel c a ra p ng nhiu dch v khc nhau vi nhng yu cu rt khc nhau. V d vi DTCH (Dedicated Traffic Channel) logical channel mang voice traffic s dng cng DCH. Trong khi vi DTCH khc ch cha mt lng nh web traffic th ch cn dng FACH l .~~~~~~~~~~physical~~~~~~~~~~~~~~~~Physical channel xc nh cch thc truyn tn hiu trn giao din v tuyn: uplink hay downlink, OVSF no, u tin v delay ra sao, tn s noS kt hp gia tn s, code v thi gian to nn cc knh vt l khc nhau.v c chia thnh hai loi: dedicated v control1. Dedicated physical channels_____a. DPDCH (Dedicated Physical Data Channel): mang DCH. Tn ti trn c uplink v downlink. iu khin cng sut closed loop (1500Hz). (c iu khin hay thc hin iu khin?)_____b. DPCCH (Dedicated Physical Control Channel): l knh mang nhng thng tin iu khin ca ring lp vt l nh cc c iu khin cng sut, cc chui ng