RRM in LTE_full

7/27/2019 RRM in LTE_full

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n tt nghi p i hoc Li noi u

LI NI U

Ngy nay, cc mng thng tin di ng ang ngy cng pht trin p ng kpthi nhu cu ngy cng cao v tc truyn dn cng nh cht lng dch v ca

khch hng, c bit l nhu cu s dng cc dch v video trc tuyn thi gian thcca cc khch hng di ng khin cho cc mng di ng th h th 3 cha th p ng. Trc tnh hnh . ITU chun ha chun 4G vi cc yu kht khe trong tiuchun IMT Advanced. T chc 3GPP a ra chun LTE, mt mng thng tin ding 3.9G trong release 8 ca t chc ny. Vi nhiu cng ngh ni bt c ngdng cho LTE, mng thng tin di ng ny nhanh chng c cc nh mng chpnhn v a vo hot ng nhiu ni trn th gii, tr thnh mt trong nhng hngquan trng nht i ln chun 4G.

i vi bt c mng thng tin di ng hay mng khng dy no, vn qun l ti

nguyn v tuyn nh tn s, khe thi gian, m, cng sut,. u rt c quan tm,bi phn b ti nguyn ny nh th no cho thch hp l mt vn khng h d giiquyt. c bit l trong mng LTE, vi nhng c im ring bit so vi cc mngthng tin di ng th h trc, t ra nhng yu cu khc bit trong vic qun l tinguyn v tuyn. Cng v l do ny, em la chn ti Qun l ti nguyn vtuyn trong mng 3GPP LTE cho n tt nghip ca mnh

Trong n ny, em i vo nghin cu cc c ch qun l ti nguyn v tuyntrong mng thng tin di ng LTE vi b cc ti bao gm 3 chng:

Chng 1: Tng quan v mng thng tin di ng LTE Chng 2: Tng quan v qun l ti nguyn v tuyn v cc c ch qun l ti

nguyn v tuyn thng gp trong cc mng thng tin di ng.

Chng 3: Cc c ch v gii thut qun l ti nguyn v tuyn trong mngLTE trong tp trung vo cc gii php gii quyt vn nhiu lin celltrong LTE.

Mc d rt c gng nhng do hn ch v mt kin thc thc t cng nh chuynmn nn chc chn bi n ca em vn khng trnh khi nhng thiu st. Em rt

mong nhn c nhng kin ng gp qu bu ca cc thy c bi n chon thin hn.

Em xin chn thnh cm n!

H Ni, thng 12 nm 2012

Sinh vin thc hin

Trn Quang Huy

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2/72

n tt nghi p i hoc Li cmn

LI CM N

C th ni tt nghip i hc l mt ct mc quan trng trong s nghip hc tpca mt sinh vin. n c ct mc quan trng , mi chng ta phi tri qua rt

nhiu th thch i hi s c gng, kin tr ca bn thn v khng th khng ni nnhng s gip tn tnh ca nhng ngi xung quanh mi chng ta.

hon thnh c n ny, ngoi s c gng ca c nhn, em cng nhnc rt nhiu s gip , ng vin t gia nh, thy c v bn b.

Li cm n chn thnh u tin em xin dnh gi ti c gio hng dn em thchin n, ThS. Dng Th Thanh T, ging vin khoa Vin thng I, Hc VinCng ngh Bu chnh Vin thng, lun tn tnh gip em trong sut qu trnhthc hin n. Mc d rt bn rn nhng c lun dnh thi gian nh hng, gp ,

sa cha gip em c c phng php nghin cu tt hn, sp xp trnh by nmt khch khoa hc v ng chun nht. n tt nghip ca em hon thnh cngnh s gip tn tnh ca c.

Em cng xin chn thnh cm n tt c cc thy c gio dy d, du dt em khnln, trng thnh ti ngy hm nay.

Xin cm n cc bn ca mnh, c bit l cc bn trong tp th lp D08VT1, cng mnh hc tp, vui chi, nu khng c cc bn th qung thi gian ngi trn ghtrng i hc s khng c c nhiu mu sc, ngha nh th. Cm n cc bn lun bn cnh gip mnh trong hc tp, ng vin v chia s nim vui ni buntrong cuc sng.

Cui cng con xin gi ti b m, gia nh, nhng ngi lun yu thng con nhtli cm n t tn y lng. cm n b m v trong sut khong thi gian va qua ht sc to iu kin, quan tm chm sc con con c th hon thnh n ny mtcch tt nht!

H Ni, thng 12 nm 2012

Sinh vin thc hin

Trn Quang Huy

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3/72

n tt nghi p i hoc Muc luc

MC LC

LI NI U...............................................................................i

LI CM N..............................................................................ii

MC LC..................................................................................iii

DANH MC HNH V...................................................................v

DANH MC BNG BIU..............................................................vi

THUT NG VIT TT...............................................................vii

CHNG 1: TNG QUAN V MNG THNG TIN DI NG LTE.........11.3.1 Kin trc mng li ca LTE................................................................................51.3.2 Kin trc mng truy nhp ca LTE.....................................................................8

Hnh 1.3 Kin trc tng qut mng truy nhp LTE........................81.3.3 Kin trc Roaming.............................................................................................9

Hnh 1.4 Kin trc roaming trong LTE.......................................101.3.4 Kin trc giao thc...........................................................................................10

Hnh 1.5 Cc giao thc trong mt bng ngi dng trong LTE.....11

Hnh 1.6 Cc giao thc trong mt bng iu khin trong LTE......12

Hnh 1.9 Cu trc tng qut chui thu v pht trong LTE...........171.5.4 Phn loi thit b ca ngi s dng................................................................20

CHNG 2: TNG QUAN V QUN L TI NGUYN V TUYN.......222.1 KHI NIM TI NGUYN V TUYN.............................................22

2.2 QUY HOCH MNG....................................................................23

2.3 KHI NIM QUN L TI NGUYN V TUYN................................23

2.4 PHN LOI CC C CH QUN L TI NGUYN V TUYN............24

Hnh 3.1 Cu trc mt khung trong truyn dn trong LTE...........33

Hnh 3.2 Vn nhiu lin cell trong mng LTE.........................34

3.2 CC CH S O CN THIT QUN L TI NGUYN V TUYN....343.2.1 Cc ch s o thc hin bi trm di ng.........................................................343.2.2 Cc ch s o c thc hin bi eNodeB........................................................35

3.3 CC GII THUT C S DNG TRONG QUN L TI NGUYN VTUYN TRONG LTE..........................................................................38

3.3.1 Cc gii thut qun l chp nhn kt ni (Admission Control)..........................383.3.2 Cc gii thut iu khin cng sut (Power control)........................................39

Hnh 3.3 Cc bn tin bo hiu gia UE v eNodeB trong c chiu khin cng sut (Power Control).......................................40

3.3.3 Gii thut thch ng kt ni (Link Adaption).....................................................41

Hnh 3.4 Hot ng ca gii thut thch nghi lin kt vng ngoi(Outer Loop Link Adaption)......................................................41

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n tt nghi p i hoc Muc luc

3.3.4 Gii thut qun l chuyn giao (Handover Control)..........................................42

Hnh 3.5 Th tc chuyn giao trong LTE....................................44

3.4 CC GII THUT QUN L NHIU LIN CELL (INTERCELLINTEFERENCE COORDINATION)........................................................45

Hnh 3.6 C ch gii quyt nhiu lin cell theo hai kiu: ngunhin ha v hp tc iu phi...............................................46

3.4.1 ICIC tnh...........................................................................................................46

Hnh 3.7 Phng n ICIC ca Ericsson.......................................46

Hnh 3.8 Phng n ICIC ca Alcatel..........................................473.4.2 ICIC bn tnh....................................................................................................47

Hnh 3.9 Phng n ICIC ca Siemens.......................................48

Hnh 3.10 Phng n ICIC da trn lu lng ca ngi dng.....493.4.3 Cc gii thut lp lch cho ti nguyn..............................................................49

3.4.4 Kt qu th nghim v nh gi hiu nng ca cc phng n ICIC...............52

Hnh 3.11 So snh thng lng cell gia 4 phng n ICIC..........53

Hnh 3.12 So snh thng lng cell bin ca cell gia 3 phngn ICIC....................................................................................53

Hnh 3.13 Trin khai mng theo phng n ICIC ng................54

Hnh 3.14 So snh thng lng ca cell mc tiu v cell hng xmtrong hai phng n ICIC tnh v ng......................................55

Hnh 3.15 So snh t l nghn gia cc phng n phn b tn skhc nhau...............................................................................563.4.5 nh gi hiu nng ca cc thut ton lp lch...............................................57

3.5 KT LUN CHNG...................................................................57

DANH MC TI LIU THAM KHO..............................................60

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5/72

n tt nghi p i hoc Danh muc hnhv

DANH MC HNH V

LI NI U...............................................................................i

LI CM N..............................................................................ii

MC LC..................................................................................iii

DANH MC HNH V...................................................................v

DANH MC BNG BIU..............................................................vi

THUT NG VIT TT...............................................................vii


Hnh 1.3 Kin trc tng qut mng truy nhp LTE........................8

1.3.3 Kin trc Roaming.............................................................................................9Hnh 1.4 Kin trc roaming trong LTE.......................................10

1.3.4 Kin trc giao thc...........................................................................................10




CHNG 2: TNG QUAN V QUN L TI NGUYN V TUYN.......22

2.1 KHI NIM TI NGUYN V TUYN.............................................222.2 QUY HOCH MNG....................................................................23





3.2 CC CH S O CN THIT QUN L TI NGUYN V TUYN....34

3.2.1 Cc ch s o thc hin bi trm di ng.........................................................343.2.2 Cc ch s o c thc hin bi eNodeB........................................................35





Hnh 3.4 Hot ng ca gii thut thch nghi lin kt vng ngoi(Outer Loop Link Adaption)......................................................413.3.4 Gii thut qun l chuyn giao (Handover Control)..........................................42

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n tt nghi p i hoc Danh muc hnhv



Hnh 3.6 C ch gii quyt nhiu lin cell theo hai kiu: ngu

nhin ha v hp tc iu phi...............................................463.4.1 ICIC tnh...........................................................................................................46




Hnh 3.10 Phng n ICIC da trn lu lng ca ngi dng.....493.4.3 Cc gii thut lp lch cho ti nguyn..............................................................493.4.4 Kt qu th nghim v nh gi hiu nng ca cc phng n ICIC...............52





Hnh 3.15 So snh t l nghn gia cc phng n phn b tn s

khc nhau...............................................................................563.4.5 nh gi hiu nng ca cc thut ton lp lch...............................................57

3.5 KT LUN CHNG...................................................................57


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n tt nghi p i hoc Danh muc bng biu

DANH MUC BNG BIU

LI NI U...............................................................................i

LI CM N..............................................................................ii

MC LC..................................................................................iiiDANH MC HNH V...................................................................v

DANH MC BNG BIU..............................................................vi

THUT NG VIT TT...............................................................vii


Hnh 1.3 Kin trc tng qut mng truy nhp LTE........................81.3.3 Kin trc Roaming.............................................................................................9

Hnh 1.4 Kin trc roaming trong LTE.......................................101.3.4 Kin trc giao thc...........................................................................................10




CHNG 2: TNG QUAN V QUN L TI NGUYN V TUYN.......222.1 KHI NIM TI NGUYN V TUYN.............................................22

2.2 QUY HOCH MNG....................................................................23





3.2 CC CH S O CN THIT QUN L TI NGUYN V TUYN....343.2.1 Cc ch s o thc hin bi trm di ng.........................................................343.2.2 Cc ch s o c thc hin bi eNodeB........................................................35





Hnh 3.4 Hot ng ca gii thut thch nghi lin kt vng ngoi(Outer Loop Link Adaption)......................................................41

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n tt nghi p i hoc Danh muc bng biu

3.3.4 Gii thut qun l chuyn giao (Handover Control)..........................................42



Hnh 3.6 C ch gii quyt nhiu lin cell theo hai kiu: ngunhin ha v hp tc iu phi...............................................46

3.4.1 ICIC tnh...........................................................................................................46




Hnh 3.10 Phng n ICIC da trn lu lng ca ngi dng.....493.4.3 Cc gii thut lp lch cho ti nguyn..............................................................49

3.4.4 Kt qu th nghim v nh gi hiu nng ca cc phng n ICIC...............52





Hnh 3.15 So snh t l nghn gia cc phng n phn b tn skhc nhau...............................................................................563.4.5 nh gi hiu nng ca cc thut ton lp lch...............................................57

3.5 KT LUN CHNG...................................................................57


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9/72

n tt nghi p i hoc Thut ng vit tt

THUT NG VIT TT

Vit tt Ting Anh Ting Vit

3GPP 3rd Generation Partnership Project D n i tc th h th ba

3GPP2 3rd Generation Partnership Project 2 D n i tc th h th ba s 2

AC Admission Control C ch chp nhn kt ni

AuC Authentication Centre Trung tm nhn thc

AMPS Advanced Mobile Phone System H thng mng di ng ci tin

BCCH Broadcast Control Channel Knh iu khin qung b

BCH Broadcast Channel Knh qung b

BLER Block Error Rate T l li nghnCCCH Common Control Channel Knh iu khin chung

CDMA Code Division Multiple Access a truy nhp phn chia theo m

CQI Channel Quality Indicator Ch th cht lng knh

DCCH Dedicated Control Channel Knh iu khin dng ring

DL-SCH Downlink Shared Channel Knh chia s ng xung

DTCH Dedicated Traffic Channel Knh lu lng dng ring

EDGE Enhanced Data rates for GSM Evolution H thng nng cao tc chomng GSM

eNodeB Evolved NodeB NodeB ci tin

EPC Evolved Packet Core Mng li gi tin ha

EPS Evolved Packet Switching Chuyn mh gi tin ha

E-SMLC Evolved Serving Location Centre Trung tm nh v di ng ci tin

ETSI European Telecommunications Standards

Institute

Vin tiu chun vin thng chu

uE-UTRAN Evolved Universal Terrestrial Radio

Access NetworkMng truy nhp v tuyn ci tin

FDD Frequency Division Duplexing Truyn song cng theo tn s

FDMA Frequency Division Multiple Access a truy nhp phn chia theo tn s

FTP File Transfer Protocol Giao thc truyn dn tp tin

FPC Fractional Power Control iu khin cng sut phn on

GBR Guaranteed Bit Rate Tc bit c m boGERAN GSM EDGE Radio Access Network Mng truy nhp ca GSM, EDGE

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GMLC Gateway Mobile Location Centre Cng trung tm nh v di ng

GPRS General Packet Radio Service Dch v v tuyn gi tng hp

GSM Global System Mobile Communications Dch v kt ni di ng ton cu

GTP-U GPRS-Tunnelling Protocol User Plane Giao thc ng hm GPRS cho

mt bng ngi dngHARQ Hybrid automatic repeat request C ch t ng gi li yu cu lai

HSDPA High Speed Downlink Packet Access Truy nhp gi tc cao ngxung

HSPA+ High Speed Packet Access Plus Truy nhp gi tc cao ci tin

HSS Home Subscriber Server My ch thu bao nh

HSUPA High Speed Uplink Packet Access Truy nhp gi tc cao ng

lnICIC Intercell Interference Coordination iu phi nhiu lin cell

IEEE Institute of Electrical and ElectronicsEngineers

Vin k thut in v in t HoaK

IMS IP Multimedia Subsystem H thng con a phng tin IP

IMT International Mobile Telecommunications Vin thng di ng quc t

IP Internet Protocol Giao thc Internet

ITU International Telecommunication Union Lin minh vin thng quc tJ-TACS Japanese Total Access Communication

SystemH thng truy nhp lin lc ca

Nht Bn

LA Link Adaption Thch ng kt ni

LTE Long Term Evolution Mng di ng pht trin di hn

LTEAvanced

Long Term Evolution Advanced Th h sau ca LTE

MAC Media Access Control Lp iu khin truy nhp mitrng

MCH Multicast Channel Knh a im

MIMO Multiple-Input Multiple-Output K thut a anten

MME Mobility Management Entity Thc th qun l di ng

MTCH Multicast Traffic Channel Knh lu lng a im

NMT Nordic Mobile Telephone H thng di ng Bc u

NRT Non Real-Time Khng theo thi gian thcNAS Non Access Stratum Lp ng dng trong LTE

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OFDM Orthogonal Frequency DivisionMultiplexing

Ghp knh phn chia theo tn strc giao

OFDMA Orthogonal Frequency Division MultipleAccess

a truy nhp phan chia theo tn strc giao

OLLA Outer Loop Link Adaption Thch ng lin kt vng ngoiOVSF Orthogonal Variable Spreading Factor M trc giao c di kh bin

PAPR Peak-to-Average Power Ratio T s cng sut nh trn cng suttrung bnh

PBCH Physical Broadcast Channel Knh qung b vt l

PC Power Control iu khin cng sut

PCCH Paging Control Channel Knh iu khin tm gi

PCFICH Physical Control Format IndicatorChannel Knh vt l ch th nh dng iukhin

PCH Paging Channel Knh tm gi

PCRF Policy Control and charging RulesFunction

B phn chc nng qun l chnhsch v tnh cc

PDCCH Physical Downlink Control Channel Knh iu khin vt l ngxung

PDCP Packet Data Convergence Giao thc iu khin hi t d liu

giPDN Packet Data Network Mng d liu gi

PDSCH Physical Downlink Shared Channel Knh chia s vt l ng xung

P-GW PDN - Gateway Node truy nhp n PDN trongmng li LTE

PHICH Physical Hybrid ARQ Indicator Channel Knh vt l ch th HARQ

PLMN Public Land Mobile Network Mng di ng mt t

PMCH Physical Multicast Channel Knh vt l a imPRACH Physical Random Access Channel Knh vt l truy nhp ngu nhin

PS Packet Scheduling Lp lch gi

PUCCH Physical Uplink Control Channel Knh iu khin vt l ng ln

PUSCH Physical Uplink Shared Channel Knh chia s vt l ng ln

RACH Random Access Channel Knh truy nhp ngu nhin

RLC Radio Link Control iu khin lin kt v tuyn

RRU Radio Resource Unit n v ti nguyn v tuyn

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RRC Radio Resource Control Lp iu khin ti nguyn vtuyn

RRM Radio Resource Management Qun l ti nguyn v tuyn

RSRP Reference Symbol Received Power Cng sut thu ca k hiu tham

chiuRSRQ Reference Symbol Received Quality Cht lng thu ca k hiu tham

chiu

RSSI Received Signal Strength Indicator Ch th cng tn hiu thu

RT Real-Time Theo thi gian thc

SAE System Architecture Evolution Kin trc h thng ci tin

SC-FDMA Single Carrier Frequency DivisionMultiple Access

a truy nhp phn chia theo tn sn sng mang

SCTP Stream Control Transmission Protocol Giao thc iu khin truyn dnlung

SIR Signal to Noise Ratio T s tn hiu trn nhiu

S-GW Serving Gateway Node phc v trong mng li LTE

TDMA Time Division Multiple Access a truy nhp phn chia theo thigian

TDD Time Division Duplexing Truyn dn song cng phn chia

theo thi gianUDP User Datagram Protocol Giao thc UDP

UL-SCH UpLink Shared Channel Knh chia s ng ln

UMTS Universal Mobile TelecommunicationsSystem

H thng thng tin di ng toncu (mng 3G)

VoIP Voice over Internet Protocol Thoi trn nn giao thc Internet

WCDMA Wideband Code Division Multiple Access a truy nhp phn chia theo m

bng rngWiMAX Worldwide interoperability for Microwave

AccessChun WiMAX

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n tt nghi p i hoc Chng 1: Tng quan v mng thng tin di ngLTE

CHNG 1: TNG QUAN V MNG THNG TIN DI NG LTE

1.1 QU TRNH PHT TRIN CA LTE

1.1.1 Bi cnh lch s

LTE l mt trong nhng bc tin mi nht trong cc h thng vin thng di ng.Cc h thng vin thng di ng mt t bt u c nghin cu v pht trin bt ut nm 1947 vi khi nim cell t phng th nghim Bell, Hoa K. Vic s dng cccell (t bo) cho php dung lng ca mng di ng tng mt cch ng k, bng cchchi nh vng ph thnh cc cell nh vi trm gc hot ng mi cell vi mt tn sring bit.

Cc h thng u tin ch gii hn trong phm vi bin gii quc gia. Chng ch cc mt s lng nh ngi dng, v gi thnh cho cc thit b l rt cao, mt khcchng li rt cng knh v ngn ngun in, v th ch thc s hot ng tt khi ikm vi t.

H thng thng tin di ng u tin vi qua m ln xut hin trn th trng vonhng nm 1980 v cn c gi l h thng Th h th nht (1G). H thng 1G sdng cng ngh analog v bao gm nhiu mng c pht trin trn ton th gii (vd nh AMPS M, TACS chu u, NMT mt phn ca chu u, J-TACS

Nht Bn v Hng Kng).

Qu trnh chuyn vng quc t tr thnh hin thc ln u tin vi s pht trinca mng di ng Th h th hai (2G) vi h thng GSM, da hon ton trn cng

ngh s. S thnh cng ca GSM da trn tinh thn hp tc pht trin bng cchtp hp mt s cc cng ty hng u ca chu u lm vic cng nhau trong t chcETSI, GSM thc s tr thnh mt chun mnh m v c chp nhn rng ri.

c tip sc bi s pht trin ca cng ngh sn xut cc thit b cm tay vihnh dng nh hn, hp thi trang v thi lng pin di hn, s chp nhn i vichun GSM vt qu k vng ban u v gip to nn mt th trng mi rt rng ln.Kt qu ca vic s thm nhp ngy cng ph bin ca cc in thoi GSM trn toncu dn n vic thng tin lin lc d dng hn trc rt nhiu, bt u l thoi v

tin nhn vn bn, sau l cc dch v d liu ngy cng pht trin hn. Vi s phttrin ca th gii, GSM bt u kt ni cc cng ng v c nhn cc vng cch xanhau m ng dy c nh khng kt ni vi nhau c hoc qu t c thtrin khai.

S tin dng ca cc mng di ng thn thin vi ngi s dng cng vi s hiubit ngy cng tng ca ngi dng vi cc cng ngh cng nh tin cy thc t cachng, to nn bi cnh pht trin thun li cho cc h thng mi vi cng ngh tintin hn v cung cp dch v tt hn. Phn tip theo s ch ra mt lot cc bc tintip ni thnh cng ca h thng GSM, m nh cao l s pht trin ca h thng LTE

(Long Term Evolution of UMTS H thng pht trin di hn ca mng thng tin ding ton cu 3G).

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1.1.2 LTE trong tng quan vi cc cng ngh v tuyn di ng

Khc vi cc cng ngh truyn dn s dng dy dn nh ng cp ng hay cpquang, ph tn v tuyn l mt mi trng c chia s bi nhiu cng ngh khcnhau v chng c th gy nhiu ln nhau.

V th, c qun qun l tn s, m c th y l ITU-R (b phn ph trch vtuyn ca lin minh vin thng quc t) v c c quan qun l cp khu vc v cp qucgia gi vai tr quan trng trong cuc cch mng ca cc cng ngh v tuyn v hquyt nh xem phn no ca ph tn v bao nhiu bng thng c s dng dnh chocc dch v v cng ngh ring bit.

Cc chc nng ca c quan qun l v cc t chc chun ha c th c tng ktli bi mi quan h nh sau:

Tc d liu = Bng thng Hiu qu s dng ph tn

(Cc quy nh v giy php) (Cng ngh v tiu chun)

(ITU-R, cc c quan qun l)

Trn cp ton th gii, ITU-R xc nh mt h cc cng ngh v phn b ccphn ca ph tn tng ng vi cc h ny. c h tr bi ITU-R, ph tn ca cccng ngh di ng c xc nh vi cc chun cng ngh v tuyn p ng c yucu ca ITU-R c th l thnh vin ca gia nh Vin thng di ng quc t(IMT). IMT bao gm cc h thng 3G v cc h thng ang c pht trin.

T gc tiu chun cng ngh, c ba t chc chnh pht trin cc tiu chun phhp vi yu cu ca IMT, v ba t chc ny tip tc chi phi bc tranh chung v cch thng v tuyn di ng (hnh 1.1).

Mi tn trn cng trong hnh 1.1 ch ra qu trnh pht trin cc chun ca t chc3GPP (D n i tc mng di ng th h th ba). 3GPP pht trin mt s chunnh sau: u tin l th h th hai, h chun GSM/GPRS/EDGE da trn nn tng atruy nhp phn chia theo thi gian v phn chia theo tn s (TDMA/FDMA); th hth ba h chun UMTS nh du bi vic s dng a truy nhp phn chia theo m(CDMA), c bit n vi cc tn CDMA bng rng (bng tn dnh cho sng mang

ln n 5 MHz) hay cn gi l WCDMA; cui cng l LTE (mng di ng pht trindi hn) da trn nn cng ngh a truy nhp phn chia theo tn s trc giao(OFDMA).

Mc tiu ca h thng LTE l m rng xu hng v cc dch v c cung cpvt xa so vi vic ch cung cp cuc gi thoi thng thng. LTE c thit k vimc ch cho php tt cc dich v hot ng trn nn chuyn mch gi thay v chuynmch knh nh trc y. Thm vo , LTE cng i km vi mt h thng mng lic ci tin SAE (Kin trc h thng tin ha). SAE cha ng mng li gi c ci tin (EPC). Kt hp vi nhau, LTE v SAE to thnh h thng chuyn gitin ha (EPS), vi vic c mng li ln mng truy nhp v tuyn u hon ton sdng chuyn mch gi.



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Hnh 1.1 Cc phng hng tin ln chun 4G

S pht trin cc cng ngh truy nhp v tuyn k tha LTE s vn c tip tcbi 3GPP. K t Release 99 chun ha i vi UMTS, hng lot cc ci tin mi cthm vo qua mi release trong khi vn m bo tnh tng thch vi cc phin bntrc : cng ngh truy nhp gi ng xung tc cao (HSDPA) trong release 5,truy nhp gi ng ln tc cao (HSUPA) trong release 6, kt hp li cn c gil truy nhp gi tc cao (HSPA), HSPA c ci tin trong release 7 thnhHSPA+ bng cch s dng iu ch bc cao kt hp vi truyn dn a lung qua cngngh a nten MIMO. Cc release 8, 9, 10 h tr vic hot ng nhiu sng mang5MHz cng lc ng ln v ng xung. Phin bn u tin ca LTE ra i thng

qua release 8 ca 3GPP vi vic s dng nhng tin b t HSPA v HSPA+. LTE cth hot ng c ch song cng theo tn s (FDD) ln song cng theo thi gian(TDD). Phin bn th hai ca LTE c pht trin tip trong cc release 9 v release10, vi tn gi LTE-Advanced.

Mi tn pht trin th hai trong hnh 1.1 cng c thc hin bi mt t chc itc tng t nh 3GPP l 3GPP2. CDMA2000 c pht trin trn nn tng cachun IS-95 Hoa K, l mng di ng t bo u tin s dng cng ngh CDMA;c pht trin ch yu M, Hn Quc v Nht Bn. Cc tiu chun ca 3GPP2 tip

tc vi vic hng n mt h thng hng n dch v d liu (EV-DO), tng tnh hng i ca 3GPP. Cn lu rng LTE c th hot ng tng thch hon ton



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vi cc h thng mng c pht trin bi 3GPP2, iu ny cho php s chuyn i ddng sang LTE vi cc nh mng i theo hng pht trin ca 3GPP2.

Mi tn pht trin cui cng c pht trin bi IEEE, to nn h 802.16 mttiu chun truy nhp bng rng khng dy. Chun ny cng hon ton da trn chuynmch gi. Chun ny cn c gi l WiMAX v c thc y bi WiMAX Forum.Phin bn u tin 802.16-2004 ch dnh cho truy nhp c nh, trong kh phin

bn th hai 802.16e h tr c di ng v v th cn c gi l WiMAX di ng.Tuy nhin, cn ch rng h thng WiMAX khng c thit k vi cng im nhnvo tnh di ng v tnh tng thch vi mng li ca cc nh iu hnh mng nh cctiu chun ca 3GPP. Tuy vy, th h mi nht c pht trin bi IEEE l 802.16mc cng mc tiu nh LTE-Advanced l p ng chun 4G t ra bi ITU.

1.2 CC C IM YU CU V MC TIU I VI LTE

Bng 1.1 So snh cc yu cu v mc tiu c bn ca LTE Release 8 vi Release 6

Yu cu cnt

Release 6 (nhmso snh)

Ch gii

ngxung Tc truyn dn

nh> 100 Mbps 14,4 Mbps

LTE: 20 MHz FDD, ghpknh khng gian 2 2.

HSDPA, 5 MHz FDD,n anten

Hiu sut s dngph tn nh

>5bps/ Hz 3bps/ Hz

Hiu sut ph tntrung bnh ca cell >1,6 2,1bps/Hz/cell 0,53 bps/Hz/cell

LTE: ghp knh khng

gian 2 2, my thu IRC.HSDPA: my thu Rake, 2anten thu.

Hiu sut ph tn bin cell

>0,04 0,06bps/Hz/user

0,02bps/Hz/user

Nh trn, gi s c 10ngi s dng mi cell

Hiu sut ph tnbroadcast

>1 bps/HzN/A Vt mang ring cho ch

broadcast

ngln Tc truyn dn

nh>50 Mbps 11 Mbps LTE: 20 Mhz FDD,

truyn dn n anten.

HSUPA: 5MHz FDD,truyn dn n anten

Hiu sut s dngph tn nh

>2,5 bps/Hz 2 bps/Hz

Hiu sut ph tntrung bnh ca cell

>0,66 1,0bps/Hz/cell

0,33 bps/Hz/cell

LTE: truyn dn nanten, my thu IRC.

HSUPA: my thu Rake, 2anten thu

Hiu sut ph tn bin cell

> 0,02 0,03bps/Hz/user

0,01bps/Hz/user

Nh trn, gi s c 10ngi dng mi cell



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Hthng

Tr mt phngngi dng (tr vtuyn hai chiu)

< 10 ms

Mc tiu ca LTE bngkhong 1/5 so vi cngngh tham chiu (release

6)Tr thit lp ktni

< 100 msT trng thi tnh sangtrng thi hot ng

Bng thng hotng

1,4 20 MHz 5 MHz(yu cu khi to bt ut mc 1,25 MHz)

Dung lng VoIP NGMN t mc tiu l > 60 phin/MHz/cell

Bng 1.1 ch ra so snh gia cc thng s ca LTE (3GPP release 8) v 3GPP

release 6. T vic so snh vi mt tiu chun c 3GPP pht trin sau 3G c th y l release 6, ta c th tng kt cc c im yu cu v mc tiu cn phi t nca LTE c nh sau:

- Gim tr, c trong qu trnh thit lp kt ni cng nh trong qu trnh truyndn.

- Tng tc d liu cho ngi dng.

- Tng tc bit bin ca cell, cho php ng b cht lng dch v;

- Ci thin hiu sut s dng ph tn;

- Tng tnh linh hot trong vic s dng ph tn, c cc bng tn mi cng nhcc bng tn s dng;

- n gin ha cu trc mng;

- Cung cp kh nng di ng mt cch thng sut v lin mch, bao gm c giacc cng ngh truy nhp v tuyn khc nhau;

- Tiu th in nng mt cch hp l i vi cc thit b u cui di ng

1.3 KIN TRC TNG QUT V MNG LTE

Trong phn ny chng ta s tm hiu cc kiu kin trc ca LTE bao gm c kintrc mng li, mng truy nhp, kin trc roaming v kin trc giao thc.

1.3.1 Kin trc mng li ca LTE

EPS cung cp cho ngi dng kt ni IP n mt PDN truy nhp Internet, cngnh chy cc dch v nh VoIP. Mt vt mang EPS s c thit lp vi mt QoSnht nh. Nhiu vt mang c th c thit lp cng lc n mt ngi s dng cung cp cc lung QoS khc nhau hoc cc kt ni n cc PDN khc nhau. V d,mt ngi dng c th nhn mt cuc gi VoIP trong khi vn ang duyt web haydownload file thng qua giao thc FTP. Mt vt mang dnh cho cuc gi VoIP cso thcung cp QoS cn thit cho cuc gi thoi, trong khi vt mang theo kiu n lc ti a



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(best-effort) thch hp cho vic duyt web hoc cc phin FTP. H thng mng cngphi cung cp qu trnh bo mt v chnh sch cho ngi dng.

Hnh 1.2 Kin trc tng qut mng li LTE

Chc nng ca cc thit b trong mng li

Mng li (c gi l EPC trong SAE) c trch nhim iu khin UE v thit lpcc vt mang. Cc node mng trong EPC gm c:

- Gateway PDN (P-GW);

- Gateway phc v (S-GW);

- Thc th qun l di ng (MME);

- Trung tm dch v nh v di ng (E-SMLC) .

Bn cnh cc node ny, EPC cng c thm cc node logic khc v cc chc nng

nh Gateway trung tm nh v di ng (GMLC), server thu bao nh (HSS) v chcnng iu khin chnh sch v tnh cc (PCRF). V EPS ch cung cp vt mang viQoS xc nh, qu trnh iu khin cc ng dng a phng tin nh VoIP c cungcp bi h thng IMS, h thng ny hot ng ring bit vi EPS. Khi mt ngi sdng chuyn vng bn ngoi mng nh ca thu bao , P-GW, GMLC v min IMSca ngi dng c th t mng nh hoc mng khch. Cc node logic trong mngli c ch ra trong hnh 1 v c cc chc nng nh c m t di y.

PCRF. PCRF chu trch nhim quyt nh chnh sch iu khin, cng nhkim sot chc nng tnh cc theo lung trong khi chc nng iu khinchnh sch bt buc i lin vi gateway P-GW. Khi chc nng PCRF cungcp qu trnh nhn thc QoS (xc nh lp QoS v tc bit) qua quyt



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nh xem mt dng d liu xc nh trn PCEF s c x l nh th no vbo m iu ny ph hp vi profile m t ca ngi s dng.

GMLC. GMLC cha cc chc nng cn thit h tr cc dnh nh v(LCS). Sau khi thc hin qu trnh nhn thc, n gi cc yu cu xc nh v

tr n MME v nhn c cc thng tin c chng chnh thc v v tr thubao.

HSS. Server thu bao nh (HSS) cha d liu m t SAE ca ngi dngnh l profile v QoS ca cc thu bao EPS v bt c hn ch no khichuyn vng. HSS cng lu tr thng tin v cc mng PDN m ngi sdng c th kt ni. iu ny c th c lu di dng tn im truy nhp(APN) (l mt nhn t tn theo quy c DNS miu t im truy nhpn PDN), hoc mt a ch PDN (ch mt hoc nhiu a ch IP cng k). Thm vo , HSS lu gi cc thng tin ng nh nhn dng ca

MME v ngi s dng ang c gn hoc c ng k. Bn cnh ,HSS c th tch hp lun c trung tm nhn thc (AuC) to ra cc vectdnh cho cc kha nhn thc v bo mt.

P-GW. P-GW chu trch nhim phn b a ch IP cho UE, cng nh bom QoS v qu trnh tnh cc da trn lung theo ng nhng quy nhca PCRF. P-GW c trch nhim lc cc gi tin IP ng xung n ngidng theo cc vt mang da trn QoS. P-GW thc hin qu trnh thit lp

bt buc QoS vi cc vt mang GBR tc cn m bo tc bit. P-GW

cng hot ng nh l mt trm trung chuyn chuyn mng gia LTEvi cc mng khng c pht trin bi 3GPP nh l CDMA2000 vWiMAX.

S-GW. Tt c cc gi tin IP u c chuyn qua S-GW, gateway ny hotng nh l cng chuyn di ng ni vng dnh cho cc vt mang d liukhi UE di chuyn gia cc eNodeB. N cng gi li cc thng tin v vtmang khi UE trang thi tnh v tm thi lu tr m d liu ng xungtrong khi MME ang bt u tm gi UE ti thit lp vt mang. Thmvo , S-GW cn thc hin mt s chc nng qun l trong mng khch,nh l thu thp thng tin tnh cc (v d nh s lng d liu gi v nhnca thu bao) v qu trnh gim st hp php. N cng hot ng nh trmtrung chuyn di ng hot ng lin mng vi cc tiu chun k thut c pht trin bi 3GPP nh l GPRS hay UMTS.

MME. MME l node iu khin x l thng tin bo hiu gia UE vmng li. Cc giao thc hot ng gia UE v mng li c gi l cc giaothcNon-Access Stratum.

Chc nng chnh c h tr bi MME c phn loi nh sau:

Cc chc nng lin quan n vic qun l vt mang. Bao gm c thitlp, duy tr v gii phng cc vt mang.



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Cc chc nng lin quan n vic qun l kt ni. Bao gm c vic thitlp kt ni v bo mt gia mng v UE.

E-SMLC. E-SMLC qun l s phi hp tng th v lp lch phn b cc tinguyn cn thit xc nh v tr ca UE ang c gn vi E-UTRAN.

N cng tnh ton v tr cui cng da trn cc c lng m n nhn c,qua c tnh tc v chnh xc t c ca UE.

1.3.2 Kin trc mng truy nhp ca LTE

Hnh 1.3 Kin trc tng qut mng truy nhp LTE

Mng truy nhp ca LTE, E-UTRAN ch n gin bao gm mt mng cc

eNodeB, nh c m t trong hnh 3. i vi lu lng thng thng dnh chongi dng, khng c mt trung tm iu khin tp trung no trong E-UTRAN, vth c th ni kin trc E-UTRAN l kin trc phng.

Cc eNodeB kt ni vi nhau thng qua giao din X2, v kt ni vi EPC thngqua giao din S1, c th hn l kt ni MME thng qua giao din S1-MME v ktni vi S-GW thng qua giao din S1-U.

E-UTRAN chu trch nhim cho tt c cc chc nng lin quan n v tuyn,c tng kt li nh sau:

Qun l ti nguyn v tuyn. Chc nng ny bao gm tt c cc chc nnglin quan n cc vt mang v tuyn nh iu khin vt mang v tuyn,



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iu khin quyn truy nhp, iu khin di ng, lp lch v cp pht ng tinguyn cho UE c ng ln v ng xung.

Nn mo u. Chc nng ny bo m vic s dng c hiu qu cc giaodin v tuyn bng cch nn cc mo u IP c mo u kh ln, c bit l

i vi cc gi kch thc nh nh trong VoIP. Bo mt. Tt c cc d liu c gi qua giao din v tuyn u c m

ha.

nh v. E-UTRAN cung cp cc thng s cn thit v cc d liu khc choE-SMLC v h tr E-SMLC trong vic xc nh v tr ca UE.

Kt ni vi EPC. Chc nng ny bao gm bo hiu vi MME v ng dn

ca vt mang ni vi S-GW.

V pha mng, tt c cc chc nng trn u thuc v eNodeB, mi eNodeB c

trch nhim qun l mt s cell. Khng nh i vi mng 2G v 3G, LTE tch hpchc nng iu khin v tuyn vo eNodeB. iu ny cho php thi gian p ngnhanh hn gia cc tng giao thc ca mng truy nhp v tuyn, qua gim tr, vci thin hiu nng. Phng thc iu khin phn tn ny khng cn n mt trungtm iu khin c kh nng sn sng cng nh nng lc x l cao, dn n vic gimgi thnh v trnh tnh trng hng mt trung tm iu khin lm ngng tr c h thng.Thm vo , LTE khng h tr chuyn giao mm nn khng cn c chc nng tptrung cc d liu kt hp trong mng.

Tuy nhin, mt h qu ca vic khng c trung tm iu khin tp trung l khiUE di chuyn, mng s phi chuyn tt c cc thng tin lin quan n UE v d nhcontext ca UE, cng vi cc d liu m, t mt eNodeB ny sang mt eNodeBkhc. Cn c cc c ch hot ng giao din X2 nhm trnh mt d liu trong qutrnh chuyn giao.

Mt tnh nng quan trng ca giao din S1 kt ni mng truy nhp vi mng li l S1-flex. y l khi nim v nhiu node mng li (MME/S-GW) c th hot ngchung trong mt vng a l, c kt ni bi mt mng mesh cc eNodeB trong khuvc . Mt eNodeB c th hot ng vi nhiu MME/S-GW. Tp hp cc MME/S-

GW gi l mtpool area. nh ngha ny cho php cc UE trong cc cell c iukhin bi mt eNodeB c th c chia s vi nhiu node CN khc nhau, qua cungcp kh nng chia s ti v trnh vic hng mt node mng li dn n mng khngth lm vic. Context ca UE thng c gi cng mt MME min l UE vn trong mtpool area.

1.3.3 Kin trc Roaming

Mt mng hot ng bi mt nh iu hnh mt nc c gi l mng di ngcng cng mt t (PLMN). Chuyn vng (roaming) l khi ngi s dng c php

kt ni vi nhiu PLMN m h khng phi l thu bao, to nn mt c tnh mnh mcho cc mng di ng v LTE/SAE khng phi l ngoi l. Ngi dng chuyn vngc kt ni vi E-UTRAN, MME v S-GW mng LTE khch. Tuy nhin,



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LTE/SAE cho php s dng P-GW ca mng nh hoc mng khch, nh hnh 4. Sdng P-GW ca mng nh cho php ngi dng c th truy nhp n cc dch v canh iu hnh mng nh ngay c khi ang mng khch. Mt P-GW ca mng khchcho php mt local breakout (truy nhp a phng) n Internet trong mng khch.

Hnh 1.4 Kin trc roaming trong LTE

1.3.4 Kin trc giao thc

phn ny chng ta s c ci nhn tng qut v kin trc giao thc trong E-UTRAN.

1.3.4.1 Mt phng ngi dng



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Hnh 1.5 Cc giao thc trong mt bng ngi dng trong LTE

Mt gi tin IP n mt UE c ng gi trong mt giao thc EPC ring bit vsau theo ng hm to gia P-GW v eNodeB truyn n UE. Cc giao thc

ng hm khc nhau c s dng thng qua cc giao din khc nhau. Giao thcng hm c xy dng bi 3GPP l Giao thc ng hm GPRS (GTP) cdng gia cc giao din li mng, S1 v S5/S8.

Chng giao thc mt phng ngi dng E-UTRAN (t m trong hnh 1.5) baogm giao thc hi t d liu gi (Packet Data Convergence - PDCP), lp iu khinlin kt v tuyn (Radio Link Control - RLC) v lp iu khin phng tin truy nhp(MAC) kt cui eNodeB v pha mng.

V khng c mt trung tm iu khin tp trung no, d liu c lu m trong

qu trnh chuyn giao do s di ng ca ngi dng trong E-UTRAN phi c x lbi chnh eNodeB. Giao thc PDCP chu trch nhim bo v d liu trong khi chuyngiao. Giao thc lp RLC v MAC u c ti khi ng trong cell mi sau khi qutrnh chuyn giao hon thnh.

1.3.4.2 Mt phng iu khin

Chng giao thc mt phng iu khin gia UE v MME c ch ra trong hnh1.6 di y.

Phn t m ch th cc giao thc AS. Cc lp thp hn thc hin cng chc nng

nh trong mt phng ngi dng ngoi tr vic khng c chc nng nn mo utrong mt phng iu khin.

Giao thc iu khin ti nguyn v tuyn (RRC protocol) c bit n nh Lp3 trong chng giao thc AS. y l chc nng chnh trong AS, chu trch nhim thitlp vt mang v tuyn v cu hnh tt c cc lp thp hn s dng bo hiu RRC giaeNodeB v UE.



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Hnh 1.6 Cc giao thc trong mt bng iu khin trong LTE

1.4 MT S C TNH C BN CA LTE

1.4.1 Khong bng tn s dng cho LTE

C rt nhiu khong bng tn c th c s dng trong h thng LTE, ty thucvo tng quc gia hoc lc a. Cc mng LTE c th trin khai trn cc bng tn

tn ti hoc bng tn mi nh:

Bng tn 900 MHz v 1800 MHz hin ang dnh cho h thng GSM;

Bng tn 850 MHz v 1900 MHz dnh cho h thng GSM Bc M;

Bng tn 700 MHz dnh cho mng truyn hnh qung b analog v ang

c thay th dn bi cc h thng truyn hnh s;

Bng tn 2100 MHz ngoi nc M, v bng tn kt hp 1700 MHz v

2100 MHz M ang c dng rng ri cho cc h thng 3G nh l

UMTS/WCDMA v HSPA; Bng tn mi 2600 MHz hin cha c s dng hu khp th gii.

1.4.2 Cc loi knh truyn dn trong LTE

Cc loi knh trong LTE c phn chia lm 3 loi:

Knh vt l: l cc knh truyn dn dng mang d liu ca ngi dng v

cc bn tin iu khin.

Knh giao vn: Cc knh giao vn thuc phn lp vt l cho php trao i

thng tin gia lp MAC v cc lp cao hn.

Knh logic: Cung cp dch v cho lp MAC trong cu trc giao thc ca LTE.

1.4.2.1 Knh vt l



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ng xung:

Knh chia s vt l ng xung (PDSCH Physical Downlink SharedChannel): S dng truyn dn d liu ca ngi dng, knh PDSCH cthit k dnh cho tc d liu cao. Cc s iu ch ty chn bao gm c

QPSK, 16-QAM, v 64-QAM. Knh qung b vt l (PBCH Physical Broadcast Channel): Knh vt l ny

mang cc thng tin h thng cho cc UE cn thit truy cp mng. N chmang cc thng tin nh dng ca cell v cc thng s cn thit kim sot truynhp cn thit. Knh ny gui bn tin mi 40 ms v ch s dng iu chQPSK.

Knh iu khin vt l ng xung (PDCCH Physical Downlink ControlChannel): knh vt l ny s dng iu ch QPSK. Mc ch chnh ca knh

vt l ny l mang cc thng tin cc thng tin phn b v lp lch ti nguynchia lm 4 loi nh sau:

Lp lch ti nguyn ng xung

Hng dn iu khin cng sut ng ln

Cp php s dng ti nguyn ng xung

Ch th cc thng tin hoa tiu hoc thng tin h thng.

Knh ch th nh dng iu khin vt l (PCFICH Physical Control FormatIndicator Channel): knh ny thng bo cho UE bit nh dng tn hiu m n

s nhn. N ch ra s cc k hiu OFDM s dng cho PDCCH l 1, 2 hay l 3.Thng tin t knh PCFICH l cn thit v UE khng c thng tin trc vkch thc ca vng iu khin. Knh ny cng s dng iu ch QPSK.

Knh vt l a im (PMCH Physical Multicast Channel): Knh PMCHmang thng tin muticast (a im), v cng nh PDSCH, PMCH c nhiu lachn iu ch bao gm QPSK, 16-QAM, 64-QAM. Thng tin multicast cgi n nhiu UE cng lc.

Knh vt l ch th HARQ (PHICH Physical Hybrid ARQ Indicator

Channel): Knh vt l ny mang thng tin phn hi i vi truyn dn ngln (ACK/NACK). Cc bn tin ACK v NACK xc nhn d liu ctruyn i hoc yu cu truyn dn li cc khi d liu thu khng chnh xc.

ng ln:

Knh chia s vt l ng ln (PUSCH Physical Uplink Shared Channel):Chc nng tng t nh PDSCH. C th dng iu ch QPSK, 16-QAM, 64-QAM. Ti nguyn trn knh PUSCH c phn b da trn b lp lch ngln.

Knh iu khin vt l ng ln (PUCCH Physical Uplink ControlChannel): Knh PUCCH cung cp thng tin iu khin ng ln v khng



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bao gi truyn cng lc vi d liu trn knh PUSCH. PUCCH cha ccthng tin iu khin bao gm cht lng knh (CQI Channel QualityIndication), p ng ACK/NACK cca UE trong c ch HARQ, v cc yucu lp lch ng ln.

Knh vt l truy nhp ngu nhin (PRACH Physical Random AccessChannel): Knh PRACH mang cc yu cu dnh cc dch v t cc thit b ding. Knh ny truyn cc yu cu truy nhp khi mt thit b di ng muntruy nhp vo h thng (thit lp cuc gi hoc p ng thng tin tm gi).

1.4.2.2 Knh giao vn

Knh giao vn trong LTE khc nhau gia ng ln v ng xung khi mi phac mt yu cu khc bit v hot ng theo nhng cch khc nhau. Cc knh giao vndng chuyn thng tin gia lp MAC v cc lp cao hn.

ng xung:

Knh qung b (BCH Broadcast Channel): Knh giao vn LTE tng ngvi knh iu khin qung b (BCCH Broadcast Control Channel).

Knh chia s ng xung (DL-SCH Downlink Shared Channel): Knhgiao vn ny l knh chnh truyn d liu ng xung. N c s dng

bi nhiu knh logic.

Knh tm gi (PCH Paging Channel): dng truyn ti knh PCCH.

Knh multicast (MCH- Multicast Channel): Knh giao vn ny dng

truyn thng tin MCCH dnh cho vic thit lp truyn dn a im.

ng ln:

Knh chia s ng ln (UL-SCH Uplink Shared Channel): Knh giao vnny l knh chnh cho vic truyn dn d liu ng ln, c s dng binhiu knh logic.

Knh truy nhp ngu nhin (RACH Random Access Channel): dnh chovic truy nhp ngu nhin.

1.4.2.3 Knh logic

Cc knh logic bao gm d liu c mang trn cc giao din v tuyn. C thphn knh logic ra lm hai loi chnh theo chc nng l: knh iu khin v knh lulng.

Knh iu khin: Cc knh iu khin trong LTE mang cc thng tin ca mt bng

iu khi, bao gm c:

Knh iu khin qung b (BCCH Broadcast Control Channel): Knh iukhin ny cung cp thng tin h thng n tt c cc u cui di ng kt nivi eNodeB.



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Knh iu khin tm gi (PCCH Paging Control Channel): Knh ny sdng cho c thng tin tm gi mt UE trong mng.

Knh iu khin chung (CCCH Common Control Channel): Knh ny dngcho cc thng tin truy nhp ngu nhi, v d nh cc hot ng thit lp kt

ni. Knh iu khin ring (DCCH Dedicated Control Channel): Knh iu

khin ny c s dng trong vic mang cc thng tin iu khin ring chomi ngi dng, v d nh cc hot ng iu khin bao gm c iu khincng sut, chuyn giao, v.v

Knh lu lng: cc knh lu lng trong LTE dng truyn d liu trong mtbng ngi s dng, gm c:

Knh lu lng dnh ring (DTCH Dedicated Traffic Channel): Knh lu

lng ny dng cho vic truyn dn d liu ca ngi s dng. Knh lu lng a im (MTCH Multicast Traffic Channel): Knh ny

c s dng cho vic truyn d liu a im.

1.5 CC K THUT MI C S DNG TRONG LTE

1.5.1 K thut a truy nhp

S dng k thut a sng mang cho a truy nhp trong LTE l la chn u tin khibt u thit k. Sau khi cn nhc la chn, cc h thng c xem xt n cho ngxung l a truy nhp phn chia theo tn s trc giao (OFDMA) v a - a truy nhp

phn chia theo m (Multiple WCDMA), trong khi i vi ng xung l a truynhp phn chia theo tn s n sng mang (SC-FDMA), OFDMA v MultipleWCDMA. Cui cng, OFDMA c chn cho ng xung v SC-FDMA c chncho ng ln. C hai phng n ny cho php s dng di tn s mt cch linh hotv hiu qu



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Hnh 1.7 Cng ngh OFDMA cho ng xung v SC-FDMA dnh cho ngln trong LTE

Hnh 1.8 Minh ha phn b sng mang cho cc ngi dng trong mng LTE

OFDMA m rng k thut a sng mang OFDM c th mang n mt h thnga truy nhp rt linh hot. OFDM chia nh bng thng c cp cho vic truyn dntn hiu thnh mt tp hp nhiu sng mang con bng hp, sp xp sao cho chng trcgiao vi nhau, cc sng mang con ny c th t mang lung thng tin hoc kt hp vinhau mang thng tin; trong OFDMA, cc phn chia bng thng ny c khai thctrong vic chia s cc sng mang con gia nhiu ngi s dng. S linh hot ny cth c s dng theo nhiu cch:

Cc khong bng tn khc nhau c th c s dng ti u m khng cn

phi thay i cc tham s c bn ca h thng hay thit k ca thit b;



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Ti nguyn truyn dn m y l bng thng c th c phn b cho cc

ngi dng v lp lch mt cch thoi mi trong min tn s;

To iu kin cho vic ti s dng tn s v iu phi nhiu gia cc cell

vi nhau.

H thng truyn dn thit k cho OFDM thng c gi thnh cao, v t s cng sutnh trn cng sut trung bnh (PAPR) ca tn hiu OFDM thng kh cao, dn nvic cn phi c mt b lc tuyn tnh RF cng sut cao. Tuy vy, nhng hn ch nykhng nh hng n vic s dng OFDM dnh cho truyn dn ng xung, nnnhng phng n trin khai vi chi ph thp s khng c u tin khi thc hin trm gc.

Hnh 1.9 Cu trc tng qut chui thu v pht trong LTE

pha ng ln, t s PAPR cao ca OFDM l cn tr ln trong qu trnh truyndn ca cc thit b u cui di ng, khi thit b di ng phi p ng yu cu vcng sut cn thit c c vng ph rng, v gi thnh ca cc b lc cng sut.SC-FDMA mang n cng ngh a truy nhp c nhiu im tng ng vi OFDMA,c bit l s linh hot trong min tn s, v vic thm vo khong bo v u cami symbol c truyn dn tng thch vi b cn bng trong min tn s c

phc tp khng cao pha thu. ng thi, SC-FDMA c t s PAPR thp hn ngk. Qua , SC-FDMA c th gii quyt nhng kh khn khi trin khai trn ng ln

qua nhng li ch ca vic truyn dn a sng mang c th c s dng trong khitrnh c gi cao ca cc thit b u cui.

1.5.2 K thut a anten



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Vic s dng k thut a anten cho php khai thc min khng gian theo mthng hon ton mi. iu ny l cn thit p ng yu cu tng hiu nng sdng ph. Vi vic s dng k thut a anten, v mt l thuyt th hiu qu s dng

ph tn thu c tng mt cch tuyn tnh vi s anten ti thiu pht v thu c trinkhai, t nht ph hp vi mi trng truyn dn v tuyn.

K thut a anten m ra rt nhiu tnh nng mi, nhng khng phi tt c cc tnhnng ny u c th d dng t c nh trong ha hn trong l thuyt khi trin khaitrong thc t. K thut a anten c th c s dng theo rt nhiu cch, da trn banguyn tc chnh, c m t trong hnh 1.10:

Tng ch phn tp. S dng phn tp khng gian c cung cp bi k thut

a anten c th tng tnh kh nng chng li nhiu a ng ca qu trnhtruyn dn.

Tng ch mng. Tp trung nng lng v mt hoc nhiu hng cho trcthng qua k thut precoding (tin m ha) hoc k thut beamforming (to

bp sng).Qu trnh ny cng cho php nhiu ngi dng cc hng khcnhau c th c phc v cng lc (nn cn c MIMO a ngi dng).

Tng ch ghp knh theo khng gian. Qu trnh truyn dn nhiu lung tnhhiu ca mt ngi dng duy nht trn nhiu phn lp khng gian to ra bis kt hp ca cc anten.

Hnh 1.10 K thut a anten trong LTE

(a) Tng ch phn tp

(b) Tng ch mng

(c) Tng ch ghp knh theo khng gian

Mt phn quan trng trong cc nghin cu v LTE chnh l vic dnh cho vic lachn v thit k cc tnh nng a dng ca k thut a anten c th trin khai trongLTE. H thng cui cng bao gm nhiu la chn b sung cho php s thch nghi ddng ty theo qu trnh trin khai mng v cc iu kin truyn dn n nhng ngidng khc nhau.

1.5.3 Giao din v tuyn chuyn mch gi



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LTE l h thng c thit k hon ton trn nn chuyn mch gi v a dch v,khng cn s ph thuc vo cc giao thc chuyn mch knh theo hng kt ni.Trong LTE, tiu ch ny c th hin qua tt c cc lp ca chng giao thc.

Cc tuyn truyn c lp lch gi nhanh trn cc giao din v tuyn c cthc hin bi HSDPA, iu ny cho php qu trnh truyn dn cc gi nh c cng .chu k bin i nh khong thi gian nht qun ca knh phainh nhanh (hnh 9). iuny t c bng ch kt hp vic ti u ha cu hnh ca lp vt l v qun l tinguyn thc hin bi cc giao thc lp lin kt ty thuc vo iu kin mi trngtruyn dn. Tnh cht ny ca HSDPA lin quan n vic kt hp cht ch gia hai lpthp hn trong chng giao thc l lp MAC v lp vt l.

Hnh 1.11 Lp lch nhanh v thch ng lin kt

Trong HSDPA, s kt hp ny bao gm c cc tnh nng nh phn hi trng thiknh nhanh, tng thch lin kt ng, phn tp lp lch trin khai vi nhiu ngi sdng, v cc giao thc truyn li. Trong LTE, vi yu cu gim tr h thng, chu kca gi c gim hn na t 2 ms i vi HSDPA xung ch cn khong 1 ms. Chuk truyn dn ngn ny cng vi cc kha cnh mi v tn s v khng gian, tip tc

m rngh hn na k thut hot ng lin lp gia lp MAC v lp vt l, bao gm cck thut sau:

Lp lch thch ng vi c chiu tn s v thi gian;

Thch ng vi cu hnh MIMO bao gm c chn la mt s lp khng gian truyn dn cng lc;

S thch ng lin kt ca qu trnh iu ch v tc bit, bao gm cc s tm c truyn i;

Nhiu ch bo co trng thi knh nhanh.



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1.5.4 Phn loi thit b ca ngi s dng

Trong thc t, cn phi thy rng th trng cc thit b cm tay rt rng ln v adng, v th LTE cn phi c kh nng h tr cc loi UE khc nhau vi kh nngkhc nhau p ng cc phn khc khc nhau ca th trng. Nhn chung, mi phnkhc th trng c nhng im u tin nht nh nh tc bit nh, kch c ca thit

b, gi thnh v thi lng pin. Mt s im i lp c th k ra y:

H tr tc d liu cao nht l cha kha quan trng UE c th thc thimt s chc nng, tuy nhin li yu cu UE phi c nhiu b nh x l dliu, khin gi ca UE b tng ln.

UE c kch thc ln nh laptop khng b hn ch nhiu v vic tiu th

in nng vi s lng anten c s dng; trong khi , cc phn khc thtrng khc yu cu nhng thit b cm tay siu mng c rt t khng giandnh cho nhiu anten hoc pin c ln.

V nhng l do nn LTE cn phi h tr cho nhiu loi UE khc nhau png nhng yu cu khc nhau ca cc phn khc th trng. Tuy nhin, h tr mtlng ln cc loi UE cng c im bt li l mo u bo hiu cho mi UE bocho mng bit cc chc nng ca n, cng nh l vic gi c b tng ln do phi mrng v tng tnh phuc tp khi th nghim tch tng thch vi nhiu cu hnh khcnhau.

Phin bn LTE u tin v th c thit kt h tr nm chng loi UE, t cc thitb cm tay gi thp dnh cho UMTS HSPA cho n cc loi in thoi cht lng cao

c th trin khai cc cng ngh m rng mi nht ca LTE.Bng 1.2 di y lit k cc chng loi UE m LTE release 8 h tr. C th thy

rng loi UE cao cp nht m LTE Release 8 h tr c th hot ng v kim sot tc d liu nh vt xa so vi yu ca Release 8.

Bng 1.2 Phn loi thit b cm tay h tr bi 3GPP release 8 v release 9



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1.6 KT LUN

Chng 1 ny trnh by mt cch tng quan v mng thng tin di ng LTE, mth thng 3.9G c pht trin bi 3GPP trn nn ca chun cng ngh 3G UMTS.Mng LTE c ng dng nhiu cng ngh mi nh k thut a truy nhp phn chiatheo tn s trc giao OFDMA ng xung, a truy nhp phn chia theo tn s nsng mang SC FDMA ng ln, k thut a anten MIMO, phn loi thit b ngis dng, bn cnh l vic chuyn ton b h thng mng truy nhp cng nhmng li sang chuyn mch gi. Cc k thut c ng dng ny gip LTE tc cc yu cu c ra nh tng tc d liu cho ngi dng (trn 100 Mbpsvi ng ln, trn 50 Mbps vi ng xung trong iu kin th nghim), ci thinhiu sut s dng ph tn (trn 5 bps/Hz vi ng xung v trn 2,5 bps i ving xung), gim tr trong qu trnh thit lp kt ni (di 10 ms trong mt bngngi dng), tng tc bit bin cell, tng tnh linh hot khi s dng ph tn, n

gin ha cu trc mng, cung cp kh nng di ng thng sut v lin mch vi c cccng ngh truy nhp v tuyn khc v bo m tiu th in nng mt cch hp l vicc thit b di ng. Cc c im tin tin ni trn gip cho LTE c bc phttrin vt bc so vi cng ngh 3G UMTS v tr thnh mt hng chnh i ln chun4G.



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n tt nghi p i hoc Chng 2: Tng quan v qun ly ti nguyn vtuyn

CHNG 2: TNG QUAN V QUN L TI NGUYN V TUYN

2.1 KHI NIM TI NGUYN V TUYN

Trc ht mun hiu v ti nguyn v tuyn, ta i vo mt khi nim c th l

n v ti nguyn v tuyn. Mt n v ti nguyn v tuyn (RRU Radio ResourceUnit) y c xc nh l mt tp hp cc thng s truyn dn c bn cn thit h tr cho sng tn hiu c th truyn i thng tin ca ngi dng tng ng vi dchv m ngi s dng. C th hn, ta c:

Trong FDMA, n v ti nguyn v tuyn tng ng vi mt khong bngthng nht nh trong tn s sng mang cho trc. V d, trong h thngTACS, mt n v ti nguyn v tuyn l mt khong 25 kHz trong bngtn 900 MHz.

Trong TDMA, mt n v ti nguyn v tuyn tng ng vi mt cp tn ssng mang v mt khe thi gian. V d, trong GSM, mt n v ti nguynv tuyn l mt khe thi gian 0,577 ms trong mi 4,615 ms mt v trnkhong bng thng 200 kHz ca bng tn 900 MHz, 1800 MHz v 1900MHz.

Trong CDMA, mt n v ti nguyn v tuyn c xc nh bi mt tn s

sng mang, mt chui m v mt mc cng sut nht nh. S khc bitchnh y so vi cc cng ngh khc l mc cng sut yu cn thit htr kt ni vi ngi dng khng c nh m ph thuc vo mc nhiu.V d, i vi h thng UTRAN FDD l khong bng thng 5 MHztrong bng tn 2 GHz cng nh mt cp m trc giao c di kh bin(OVSF - Orthogonal Variable Spreading Factor) v m trn c xc nh h tr cho mt dch v cho trc. Tuy nhin, s lng cc ti nguyndnh cho cng sut pht cng thay i theo thi gian ty thuc v cc yu t

bi cnh, v d nh iu kin truyn dn, nhiu, mc ti ca cell, .

Bn cnh cc yu t chnh v mt vt l (tn s, khe thi gian, chui m v mccng sut), cn c cc yu t vt l khc nh hng n qu trnh truyn dn nh cc

s iu ch, s m ha knh, . C th thy r rng ty thuc vo cc phngn trin khai, cc nhn t nh hng c th dn n hiu nng khc nhau. Tuy vy, vinh ngha khi nim v mt n v ti nguyn v tuyn, ch c nhng thng s truyndn chnh c cn nhc n.

Cn phi ch rng, vi cc h thng a dch v, mi dch v c th yu cu mts lng n v ti nguyn v tuyn nht nh. Cc dch v cn tc bit cao r rngcn nhiu ti nguyn v tuyn. S cn thm cc khong bng tn nu c ch truy nhpl FDMA, thm cc khe thi thi gian trong trng hp TDMA hoc thm cc chuim cng vi mc cng sut pht cao hn nu s dng CDMA.



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2.2 QUY HOCH MNG

Mc tiu ca nh iu hnh mng khi trin khai mt h thng l c kh nng phcv cc khch hng vi QoS ng yu cu trong vng ph. t c iu ny, mtmng tng qut phi lin quan n nhiu vn ph nh vng ph ca mng, thit kmng truyn dn v mng li.

Tp trung vo phn v tuyn, vn y l phi cung cp s lng n v tinguyn v tuyn trong vng phc v v m bo cht lng.

Cn lu rng vic u t ca nh iu hnh vo cu trc mng v tuyn ch yul vo s cc trm gc hay cc nodeB c trin khai, qua :

Tng s ngi dng c phc v. S lng ngi dng cng cao, dung

lng ca mng cng phi cao, v th cn thm cc trm gc.

M rng vng phc v. Vng phc v cng rng, s trm gc cng tng.

Tng tc truyn dn trung bnh vi ngi dng. Tc bit cng cao, slng cc ti nguyn v tuyn cn thit cng cao.

Tng mc QoS mong mun. QoS cng cao, ti nguyn v tuyn cn thitcng phi nhiu.

Vn quyt nh y chnh l gi gn vi vic m bo QoS. Cch c bn nht m bo QoS l s dng nhiu ti nguyn hn mc cn thit. Tt nhin, vn ng quan tm y l cung cp mc QoS mong mun vi ti nguyn ti thiunht c th, qua lm gim tin vn u t trong khi vn c th p ng nhng yu

cu thit k mng.C th ni kt qu ca vic quy hoch mng v tuyn s l cung cp s lng RRU

theo vng phc v bng cc phng tin l mt cu trc mng v cu hnh cho trcca cell. Cn ch rng, khi m s lng dch v v mc s dng dch v thay itheo thi gian v khng gian th s lng RRU c cung cp cng phi theo i tytheo thi gian v khng gian. V th nn, quy hoch mng v tuyn l mt qu trnhng, lin tc bin i.

2.3 KHI NIM QUN L TI NGUYN V TUYN

Nh nu phn trn, mng v tuyn trin khai p ng mt tp hp cc yucu v n v ti nguyn v tuyn, do , mt s lng nht nh ca RRU c cungcp trong vng phc v vo khong thi gian nht nh. V th, qu trnh phn b thchhp vi ngun ti nguyn v tuyn c cung cp n ngi dng trong mng l rtcn thit, khi m ngi dng yu cu dch v v di chuyn. Cc chc nng qun l tinguyn v tuyn c vai tr chnh l phn b v qun l cc n v ti nguyn v tuync cung cp.

V c bn, bn cht ca h thng di ng l ng. Tnh ng c hp thnh tnhiu yu t: iu kin truyn dn, iu kin v lu lng ti, iu kin nhiu, . Do

, cn phi c mt phng php qun l ng i vi ti nguyn v tuyn, cc c ch



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RRM lin quan n mt s lng ln cc thng s cn chn la, tnh ton, phn tchv ti u.

Theo mt kha cnh khc th qun l ti nguyn v tuyn l qu trnh iu khin mc h thng i vi nhiu ng knh v cc c tnh truyn dn v tuyn. Cc c chqun l ti nguyn v tuyn (RRM) rt a dng, c th k ra y nh iu khin cngsut, phn b knh, iu khin chuyn giao, lp lch gi. k c cc s iu ch v s m ha sa li,v.v Mc tiu y l phn b hiu qu RRU, s dng ti thiu tinguyn trong khi vn t c hiu sut mong mun.

2.4 PHN LOI CC C CH QUN L TI NGUYN V TUYN

Cc c ch qun l ti nguyn v tuyn c th c phn loi theo mt s tiu ch sau:

a) Tiu ch u tin l theo c s da trn ca c ch qun l:

Cc c ch qun l ti nguyn v tuyn theo gc nhn t mng, v d nh: iu

khin tip nhn kt ni (Admission control), iu khin ti (Load Control), lplch gi (Packet scheduler), qun l ti nguyn (Resource Manager),

Cc c ch qun l ti nguyn v tuyn theo gc nhn t kt ni, v d nh: iukhin chuyn giao (Handover Control), iu khin cng sut (Power Control)

b) Tiu ch th hai l tnh ng ca c ch qun l:

C ch qun l ti nguyn v tuyn c th l tnh, thng c thit lp ngay t

khi thit k, quy hoch mng v cc cell. V d nh: k hoch phn b tn s,chn la cc thng s iu ch v m ha knh, phn tp khng gian vi trm

gc, C th thy y l cc c ch truyn thng thng c s dng trongnhiu mng thng tin v tuyn nh l cc h thng mng 1G v 2G. Chng taquan tm hn n cc c ch qun l ng.

C ch qun l ti nguyn v tuyn ng: cc c ch ny thay i thch ng

theo cc thng s nh ti lu lng, v tr ngi dng, QoS yu cu.v.v Ccc ch RRM ng c cn nhc ti trong khi thit k h thng, nhm gimvic ph thuc vo vic hoch nh cell th cng t v hng ti vic ti sdng ti nguyn (tn s chng hn) nhiu hn, qua ci thin hiu nng hthng. Mt s cc c ch RRM ng c th k ra gm:

C ch iu khin cng sut (Power control);

C ch thch ng kt ni (hay m ha v iu ch thch ng) (Link

Adaption);

C ch qun l tip nhn kt ni (Admission control);

Phn b bng thng ng (Dynamic bandwidth allocation);

C ch lp lch gi (Packet scheduler);

C ch iu khin chuyn giao (Handover control);

C ch lc thch ng (Adaptive filtering);



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....

Tuy nhin cn lu l cc c ch ny khng c mt thc th vt l nht nh ch thc hin chng trong mng li, bn cnh cc c ch ny thng c lin quan chtch vi nhau, kt hp vi nhau c th t c hiu qu khi phn b v qun l tinguyn.

2.5 CHC NNG V NGUYN TC CA MT S C CH QUN L TINGUYN V TUYN C BN

Phn ny s trnh by chc nng, mc ch v nguyn tc hot ng ca mt s cch qun l ti nguyn v tuyn c bn, trong ch trng ch yu vo cc c ch clin quan n cc h thng mng di ng.

2.5.1 C ch qun l tip nhn kt ni (Admission Control)

Chc nng ca c ch qun l kt ni l x l tt c cc lu lng n, kim tra

xem kt ni mi c c chp nhn thit lp trong h thng hay khng, v nu c thto cc thng s cho kt ni mi. C ch qun l tip nhn kt ni xy ra khi c kt nimi c thit lp, trong qu trnh chuyn giao v trong khi thay i cc vt mang vtuyn.

C th hn, c ch qun l tip nhn kt ni quyt nh xem mt vt mang truynhp v tuyn c c chp nhn hay khng. Cc yu cu thit lp vt mang cchp nhn khi h thng c th p ng c mc QoS cn thit v mc QoS ca cckt ni ang tn ti khng b nh hng bi kt ni mi.

V thng lng ti a ca mt cell lin quan mt thit n nhiu hay mc ti ca

cell, vic s dng cc thut ton qun l kt ni da trn vic tnh ton c tnh v tnhtrng ti hin ti ca cell cng nh s gia tng ti to ra bi yu cu mi. C ch nythng c thc hin mt cch ring r ng ln v ng xung ca h thng vtuyn, l do l do nhng khc bit trong hai hng kt ni. Tuy vy, mt yu cu thitlp kt ni ch c chp nhn sau khi c cp php t c hai c ch tng ng ng ln v ng xung.

i vi cc th h mng di ng mi t 3G tr i, khch hng s dng nhiu dchv hn l ch dng dch v thoi, v d nh cc dch v a phng tin (v d: gi

thoi video, xem video trc tuyn, duyt web,v.v) vi cc yu cu v QoS rt khcnhau. V c bn cc dch v c th chia ra theo hai loi l: lu lng theo thi gianthc v lu lng khng theo thi gian thc. R rng l, iu kin chp nhn ktni khng theo thi gian thc d dng hn so vi kt ni theo thi gian thc, v cc cch qun l ti nguyn v tuyn khc c th gii hn truyn dn khng theo thi gianthc trong trng hp ti trn giao din v tuyn b vt qu. Thng thng cc lulng khng theo thi gian thc c chp nhn khi c ch ny lm vic vi c chlp lch gi (Packet scheduler) t c qu trnh lp lch ti u.

Mt v d v vai tr ca c ch ny trong mt h thng v tuyn, y l h thng

3G UMTS nh trong hnh 2.1 di y.



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C th thy r trn hnh v c ch Admission control. Nu kt ni c chp nhn,SRNC s s dng cc ti nguyn vi tuyn v cc giao din Iub bt u thit lp vtmang v tuyn. Cng lc, cc kt ni cn thit cng c thit lp giao din Iu. Nuqu trnh thit lp hon tt, mt bn tin thng bo v cng nh vt mang truy nhp vtuyn s c thit lp.

Hnh 2.1 Minh ha cho chc nng ca c ch AdmissionControl trong mng 3G UMTS

2.5.2 C ch iu khin ti (Load control)

C ch iu khin ti (hay cn gi l iu khin nghn Congestion Control) l cch c s dng trong nhng tnh hung m vic m bo QoS c nguy c b ph vdo nhng vn ca h thng (v d nh s di chuyn ca ngi s dng, s tng ca

nhiu, s thay i ca lu lng dch v,v.v). Cn lu rng, mc d c nhng cch qun l kt ni cht ch, cng nh vic mng v tuyn c kh nng thch ng mnhm vi cc bin i bt ng, vn s lun c kh nng xy ra cc tnh hung qu ti, vdo c ch iu khin nghn lun cn phi c.

Cc tnh hung nghn trong mi trng v tuyn thng gy ra bi nhiu vt qumc ngng c ng ln v ng xung. V th cc c ch x l nghn cn phitp trung vo tnh trng ca mng gii quyt tnh hung qu ti ang gp phi. Qutrnh x l ny s da trn cc thng s ca mng, nh cng sut pht ng xung,ch s ti ca cell ng ln, v.v nhng thng s cn phi c cn bng thchhp trnh trng hp pht hin sai nghn (v d nh kch hot cc c ch gii quytnghn d thc t giao din v tuyn khng b qu ti) hoc khng pht hin c



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nghn (v d nh khng kch hot c ch iu khin nghn khi giao din v tuyn thcs b nghn). Thm vo , c ch qun l nghn cn phi phn ng nhanh trong tnhhung qu ti ngn vic gim cht lng ca kt ni.

Thc t th iu khin nghn lin quan mt thit n cc c ch RRM khc, c thhn qun l nghn thng c h tr bi c ch qun l kt ni (t chi kt ni mikhi mng ang b nghn) hoc c ch chuyn giao (chuyn cc kt ni cell b nghnsang cc cell lin k khng b nghn). Chnh xc hn, cc hot ng ny ph thuc votnh hnh, nguyn nhn nghn cng nh vic cc dch v no ang c s dng thiim nghn. Mt v d c th c ch ra trong hnh 2.2

Hnh 2.2Nguyn tc hot ng ca c ch iu khin ti (Load Control)

Trong v d ny, s c mt mc ti nh (ngng) c quy nh trc trongmng. Thng thng, ti s bao gm ca cc dch v thi gian thc (Real Time - RT)v dch v khng theo thi gian thc (Non Real Time - NRT). Nu ti lu lng theothi gian thc di gi tr ngng c nh trc, c th gii quyt nghn bngcch gim tc truyn ti i vi nhng ngi ang s dng dch v khng theo thi

gian thc nh trong hnh 2.2(a). Trong tnh hung kh khn hn, c th tt c cc qutrnh truyn dn khng theo thi gian thc trong cell phi b chn li. Nu ngay c vic



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ny cng khng gim nghn, cn phi c s gip t cc cell lin k, bngcch gim nhiu lin cell ca cc dch v khng theo thi gian thc. Nu vn khng (nh trong hnh 2.2(b)), cn phi gim lun c ti i vi dch v thi gian thc, trongtrng hp ny c th s c mt s cuc gi b rt mng tr li bnh thng.

2.5.3 C ch lp lch gi (Packet Scheduling)

C ch ny nhm x l cc lu lng n ca cc dch v khng theo thi gianthc (ngi dng d liu gi) ng thi chia s cc ti nguyn v tuyn mt cch hpl gia cc vt mang v tuyn. N s quyt nh khi no qu trnh truyn gi c btu v tc bit s c s dng trong khi truyn. C ch ny thng hot ng theocc chu k ngn, c th thch nghi kp thi vi s thay i trong khong ngn camc nhiu. C th thy lp lch gi lin quan n c ch iu khin ti (hay iu khinnhiu) khi n qun l nhng vt mang v tuyn khng theo thi gian thc v thc hincc hot ng iu khin (gim tc bit hoc ngt kt ni nu cn) bo m ti

ca cell nu cn thit.Hot ng ca c ch lp lch gi c th c m t nh sau (Hnh 2.3)

Hnh 2.3Nguyn tc hot ng ca c ch lp lch gi (Packet Scheduling)

Hnh 2.3(a) m t mc ti ca mt cell bao gm c lu lng thi gian thc vkhng theo thi gian thc, mc ti di mc ngng cho php ca cell, v th c

dung lng trng nht nh tn ti trong cell. V th, mc tiu ca c ch lp lch gic ch ra trong hnh 2.3(b) trong khong dung lng trng s c s dng htbi mt lng ti khng theo thi gian thc nht nh. iu ny c th t c bng



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cch cho php cc phin truyn dn ca nhng ngi s dng khc khng bao gmnhng ngi dng ang s dng dch v hoc tng tc bit ca nhng ngi dngny, hoc c th kt hp c hai phng php ny nhng khng ti vt qu mcngng.

2.5.4 C ch iu khin cng sut

Mc tiu chnh ca c ch iu khin cng sut l duy tr cht lng ca kt ni vtuyn, ng thi lm ti thiu v kim sot cng sut s dng cho giao din v tuyn. t c iu ny, cng sut pht phi c la chn mt cch hp l nht c th.V sao phi nh vy? C mt s l do cn phi c cn nhc n nh trnh by diy.

Nu cng sut pht tng trn kt ni v tuyn th c th t c mt s li ch nhsau:

Nhn chung, trong bt c iu kin no ca knh truyn, cng tng cng sut

pht th s dn n cng sut tn hiu thu tng theo. iu ny s gip tng tl tn hiu trn nhiu (SNR) my thu, qua lm gim t l li bit trn ktni v tuyn.

T l tn hiu trn nhiu cao hn cng cho php h thng s dng c chthch ng kt ni (link adaption) truyn d liu tc bit cao hn, dnn hiu qu s dng bng tn cao hn.

Trong mt knh v tuyn c phainh, s dng cng sut truyn cao hn

gip chng li vic tn hiu b nh hng.

Tuy vy, cng sut truyn dn cao cng dn n nhng h qu khng tt:

Cng sut truyn tng ca cc thit b pht tng cao dn n thi lng pingim nhanh. y l mt vn cn quan tm khi m cc thit b di ngthng khng c c ngun cp n nh nh trm gc.

Cng sut pht cao cng lm tng nhiu i vi nhng ngi s dng khc

cng tn s.

Do vy c th thy khng d c th iu chnh t c cng sut pht thch

hp, phng php tt nht l cn bng gia hai mt li ch v h qu ca c chny. C ch ny thng c s dng trong cc mng di ng, nht l nhng mng ding s dng cng ngh CDMA do cc thit b di ng trong mng CDMA u dngchung mt tn s nn khi hot ng chng thng gy nhiu cho nhau nu cng sut

pht ln.

C ch ny thng c phn chia ra lm hai phng php chnh l iu chnhcng sut vng h (Open-loop Power Control) v iu khin cng sut vng kn(Closed-loop Power Control).

Vi iu khin cng sut vng h, trm di ng gim st tng cng sut thu ct trm gc, cng sut o c cho thy tn hao ng truyn vi ngi s dng.Thit b u cui iu chnh cng sut pht t l vi tng cng sut m n thu c.



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Trong phng php ny, trm gc khng tham gia vo cc th tc iu khin cngsut. Trong khi , phng php iu khin cng sut vng kn i hi trm gc phithng xuyn lin h vi trm di ng n thay i cng sut mt cch thch ng.Trm gc nh gi cng sut tn hiu ca ngi dng ng ln v so snh n vicng sut ngng danh nh. Trn c s mc thu cao hay thp hn ngng, trm gc

pht lnh iu khin n my di ng iu chnh cng sut pht.

2.5.5 C ch qun l chuyn giao (Handover Control)

Mc ch ca c ch qun l chuyn giao l x l v thc hin tt c cc quyt nhchuyn giao, c ch ny cn phi kim sot c tp hp cc trm gc kt ni vi trmdi ng trong cng mt thi im.

Vi bt c loi chuyn giao no (chuyn giao cng hay mm) c ch ny chuyngiao cng hot ng theo ba bc ring bit: o lng, quyt nh v thc hin.

Cc php o c thc hin bi thit b u cui c th chuyn v mng theo chuk hoc khi c nhng s kin bt ng xy ra. Cc php o ny c quy nh rt chnhxc v c chia ra lm nhiu loi khc nhau: cng tn s, gia cc tn s khc nhau,gia cc cng ngh truy nhp v tuyn khc nhau.

Cc php o trong cng tn s thng c dng xc nh cc cell hng xm cng mt phn lp (v d: microcell, macrocell,v.v). Cc php o lin tn s cthc hin cng phn lp khi m nhiu sng mang c phn b cho mt cell chotrc tng thng lng hoc do cu trc cell c hoch nh t trc bi nh iuhnh mng. Cc php o lin mng c thc hin khi c nhiu hn mt mng truy

nhp v tuyn hot ng trong khu vc phc v.Quyt nh chuyn giao c thc hin bi cc thut ton chuyn giao, trong

knh hoa tiu ng mt vai tr quan trng, khi m cc quyt nh hu nh u da trnso snh gia cc php o trn knh hoa tiu. Ch cn tng hoc gim mc cng sut

pht ca knh hoa tiu, s c nhiu ngi s dng c kt ni hoc b t chi kt nivi cell.

Tuy rng khi nim v qun l chuyn giao kh n gin, nhng trong thc t phctp hn nhiu v c rt nhiu thng s nh hng n quyt nh chuyn giao.

C ch chuyn giao cng kt hp cht ch vi cc c ch qun l ti nguyn vtuyn khc, v d nh hp tc vi c ch iu khin nghn chuyn nhng lu lngvt qu ngng ca mt cell sang cc cell hng xm hay lm vic vi c ch qun ltip nhn kt ni trong qu trnh chuyn giao.

2.6 KT LUN CHNG

Chng 2 trnh by v khi nim ti nguyn v tuyn v cc c ch c bn qunl ti nguyn v tuyn trong mng di ng khng dy. V c bn, n v ti nguyn vtuyn l mt tp hp cc thng s truyn dn c bn cn thit h tr cho sng tnhiu c th truyn i thng tin ca ngi dng tng ng vi dch v m h s dng.n v ti nguyn v tuyn c th l mt khong tn s, mt khe thi gian hay mt mtri ph, mt tp hp sng mang con hoc kt hp gia cc yu t li.



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Phn tip theo trong chng lit k cc c ch qun l ti nguyn v tuyn vphng php phn loi cc c ch ny. Mt s c ch qun l ti nguyn v tuyn cbn c trnh by trong chng gm c:

C ch qun l tip nhn kt ni (Admission Control);

C ch iu khin ti (Load Control/ Congestion Control); C ch lp lch gi (Packet Scheduling);

C ch iu khin cng sut (Power Control);

C ch qun l chuyn giao (Handover Control).

Bn cnh cn mt s c ch khc nh: thch ng kt ni (Link Adaption), phnb bng thng ng (Dynamic Bandwidth Allocation), Cn lu l trong thc t,khng c thc th vt l c th trong mng thc hin ring r tng chc nng qun lny m cc c ch u lin kt vi nhau cht ch p ng kp thi vi nhng thayi ca mng.



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n tt nghi p i hoc Chng 3: Qun ly ti nguyn v tuyn trong mng LTE

CHNG 3: QUN L TI NGUYN V TUYNTRONG MNG LTE

3.1 C IM CA QUN L TI NGUYN V TUYN TRONG MNGLTE

So vi cc mng di ng th h trc nh GSM/GPRS, 3G WCDMA, mng LTEc nhng c im khc, dn n c nhng khc bit trong cc vn v qun l tinguyn v tuyn so vi cc mng th h trc.

u tin hy i vo khi nim v n v ti nguyn v tuyn (hay khi ti nguynv tuyn) ca mng LTE. Thnh phn ti nguyn nh nht tng ng vi mt k hiuOFDM trn mt sng mang OFDM. Cc thnh phn ti nguyn ny c t chc lithnh cc khi ln hn trong c trng thi gian v tn s, vi by k hiu OFDM tothnh mt khe c di 0,5 ms v c 12 sng mang con, gi l mt khi ti nguyn.Hai khe thi gian lin tip to thnh mt sub-frame v mi sub-frame to thnh mt

frame c di 10 ms. B lp lch c th phn b cc khi ti nguyn ny theo lnlt mt cp hai khi ti nguyn lin tip, v th n v ti nguyn nh nht c phn

b l hai khi ti nguyn.

Hnh 3.1 Cu trc mt khung trong truyn dn trong LTE

Tuy vy c mt im khc bit khi cp pht ti nguyn trn ng xung v ng

ln. V ng ln s dng k thut a truy nhp SC-FDMA, nn vic phn b cc khiti nguyn cho mi UE phi l cc khi ti nguyn lin tip.

im khc bit ln nht trong qu trnh qun l ti nguyn v tuyn bt ngun tcu trc ca mng truy nhp LTE. Nh cp chng 1, mng truy nhp LTE ch

bao gm mt mng li cc eNodeB m khng c mt trung tm qun l tp trung nonh RNC trong mng 3G UMTS hay BSC trong mng 2G, bn cnh , mng LTE cch s ti s dng tn s bng 1, hay ni cch khc tt c cc cell u c php sdng chung ton b di bng tn cp pht. im ny dn n vic s dng tn s hiuqu hn nhng ng thi cng dn n yu cu phi gii quyt vn nhiu lin cell



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Hnh 3.2 Vn nhiu lin cell trong mng LTE

UL: UE c th gy nhiu i vi cc eNodeB hng xm

DL: eNodeB c th gy nhiu ln cc UE cell hng xm

Hnh 3.2 minh ha cho tnh hung nhiu lin cell. Trong h thng LTE, h thngti s dng tn s bng 1, tt c cc khi ti nguyn hay ni cch khc tt c bng tnu c cc cell s dng. Trong cc h thng nh th, cc UE ang hot ng c th

gy ra nhiu ng ln i vi cc eNodeB cc cell hng xm, ng thi eNodeBcng c th gy ra nhiu ng xung i vi cc UE ang hot ng cell hngxm. Tt nhin eNodeB c th thc hin cc gii thut lp lch phn b ti nguyn cho

php chng gim cc nhiu lin cell nh hng n cc cell ln cn bng cch cn thnla chn cc khi ti nguyn s dng.

3.2 CC CH S O CN THIT QUN L TI NGUYN V TUYN

Phn ny s gii thiu v nhng thng s cn o c phc v cho vic qun l tinguyn v tuyn c thc hin bi c eNodeB v trm di ng.

3.2.1 Cc ch s o thc hin bi trm di ngCc thng s o c thc hin bi trm di ng c lit k di y:

Cng sut thu ca k hiu tham chiu (RSRP Reference Symbol Received

Power): c xc nh cho cell ang c xt n, tnh trung bnh tuyn tnhtrn tng cng sut (theo n v W) ca cc n v ti nguyn mang tn hiutham chiu ca cell trong khong bng tn ang c xem xt.

Ch th cng tn hiu thu (RSSI Received Signal Strength Indicator): chs ny bao gm tng cng sut thu bng rng i vi UE t tt c cc ngun,

bao gm c c dch v ng knh v cc cell khng phc v cho UE, nhiuknh ln cn, nhiu nhit, v.v



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Cht lng thu ca k hiu tham chiu (RSRQ Reference Symbol ReceivedQuality): ch s ny c xc nh bi t s NRSRP/(RSSI ca sng mang E-UTRAN), vi N l s cc vt mang v tuyn trong khong bng thng c o

bi RSSI ca sng mang trong E-UTRAN. Cc php o t s v mu s phic thc hin trn cng mt tp cc khi ti nguyn.

Ch th cht lng knh (CQI Channel quality indicator) trn mi bng con,

trn mt tp bng con v trn ton b bng tn.

Bng 3.1 Cc ch s o trong LTE thc hin bi MS

Ch s o Mc ch Chu k o L1

Giao thc Lc cc lpcao hn

RSRP Handover, la chn cell 200 ms RRC C

RSRQ Handover, la chn cell 200 ms RRC C

RSSI Handover lin tn s vHandover gia cc mngtruy nhp v tuyn vi

nhau

200 ms RRC C

CQI Lp lch, iu khin cng

sut ng xung, thchng kt ni

1 chu k

truyndn(1ms)

MAC Khng

3.2.2 Cc ch s o c thc hin bi eNodeB

Trong mng truy nhp v tuyn E-UTRAN ca LTE, mt s thng s o nht nhc thc hin trong eNodeB v khng c trao i gia cc eNodeB. Cc thng sny khng cn phi c mt tiu chun, m ch yu hot ng c lp. Mc khc, ccthng s trao i gia eNodeB thng qua giao din X2 cn phi c chun ha.

Cc thng s cn o phc v cho cc mc ch sau: Chuyn giao ni mng LTE v gia cc loi mng truy nhp v tuyn vi LTE

Qun l chp nhn kt ni v qun l nghn

Hp tc gim nhiu lin cell

Hot ng v bo tr

Cc thng s cn o ca eNodeB (trong hu ht c thc hin c th m khngcn chun ha) nh sau:

Cng sut pht tng ng xung (DL Total Tx Power): Cng sut pht casng mang trn ton b bng tn truyn dn ca cell.



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Cng sut pht khi ti nguyn ng xung (DL RB Tx Power): Cng sutpht sng mang o trn mt khi ti nguyn.

Cng sut pht ng xung trn mi nhnh anten (DL Tx Carrier power per

antenna branch): Cng sut pht sng mang o trn ton b bng thng trnmt nhnh anten.

Cng sut pht khi ti nguyn ng xung trn mi nhnh anten (DL RB Tx

Power per antenna branch): Cng sut pht ca sng mang trn mt khi tinguyn.

T l s dng tng ti nguyn ng xung (DL Total RB usage): tnh bng ts ca cc khi ti nguyn ng xung c s dng trn tng cc khi tinguyn ng xung kh dng (hoc n gin l s cc khi ti nguyn ngxung c s dng).

T l s dng tng ti nguyn ng ln (UL Total RB usage): tnh bng t scc khi ti nguyn ng ln c s dng trn tng cc khi ti nguyn khdng (hoc n gin l cc s cc khi ti nguyn ng ln c s dng).

Hot ng ca khi ti nguyn ng xung (DL RB activity): tnh bng t s

ca thi gian c ln lch ca khi ti nguyn ng xung trn khong thigian o.

Hot ng ca khi ti nguyn ng ln (UL RB activity): tnh bng t s cathi gian c ln lch ca khi ti nguyn ng ln trn khong thi gian o.

T l mt gi trn ng xung: t l mt gi ca gi GTP-U (hay frame) gi ibi cng truy nhp trn nn mt phng ngi s dng S1. Thng s ny cnphi c o trn mi lung lu lng. eNodeB s s dng s cc gi GTP-U(hoc frame) o t l mt gi ng xung.

T l mt gi trn ng ln: t l mt gi ca gi GTP-U (hay frame) gi i bicng truy nhp trn nn mt phng ngi s dng S1. Thng s ny cn phic o trn mi lung lu lng. eNodeB s s dng s cc gi GTP-U (hocframe) o t l mt gi ng ln.

RTWP ng ln (UL RTWP): Tng cng sut thu bng rng (Received totalwideband power) bao gm c nhiu c o trn ton b bng tn truyn dnca cell eNodeB.

Cng sut thu khi ti nguyn ng ln: tng cng sut thu bao gm c nhiu

c o trn mt khi ti nguyn ti eNodeB.

SIR ng xung (trn mi UE) (UL SIR): t s ca cng sut thu ca tn hiu

pht tham chiu bi UE trn tng nhiu thu c bi eNodeB trn bng tn mUE chim gi.

BLER HARQ ng ln (BLER HARQ UL): t s li khi (Block Error Rate)da trn qu trnh kim tra CRC ca mi cp truyn khi HARQ.



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Tr truyn dn (Propagation Delay): Thi gian tr truyn dn trn mt hngtnh trn mt qu trnh truyn dn truy nhp bt k.

lch thi pht ca UE (UE Tx time difference): lch v thi gian gia

qu trnh nhn tn hiu pht ca UE v thi gian truyn dn ca k hiu thamchiu.

Cng sut pht tn hiu tham chiu ng xung (DL RS Tx Power): c xc

nh trong cell ang c xt n, tnh bng trung bnh tuyn tnh trn tngcng sut (tnh theo n v W) ca cc n v ti nguyn mang tn hiu thamchiu c trng cho cell c pht i bi eNodeB trong khong bng tn hotng ca n.

i vi mc ch hp tc gia cc cell chng nhiu lin cell, cc ch s o titrong mt phng ngi s dng s rt hu dng (v d nh s lng cc gi hoc cc

bit gi i trong mi giy trn nn tng ngi s dng)

Bng 3.2 Cc ch s o trong LTE c thc hin bi eNodeB

Ch s o Mc ch Chu k o Giaodin

Lc cc lpcao hn

DL Total Tx Power HO, Load control (AC, CC),

ICIC

~100ms X2 C

DL RB Tx Power HO, Load control (AC, CC),

ICIC

~100ms X2 C

DL Tx Carre Powerper antenna branch

HO, Load control (AC, CC),

ICIC trigger HO

~100ms X2 C

DL Total RB Usage HO, Load control (AC, CC),

ICIC

~100ms X2 C

UL Total RB usage HO, Load control (AC, CC),

ICIC

~100ms X2 C

DL RB activity ICIC ~100ms X2 C

UL RB activity ICIC ~100ms X2 C

DL Transport networkloss

HO, Load control (AC, CC) ~100ms NieNodeB

C

UL Transport networkloss

HO, Load control (AC, CC) ~100ms S1 C

UL Received TotalWideband Power

HO, Load control (AC, CC) ~100ms X2 C



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UL Received ResourceBlock Power

HO, Load control (AC, CC),

ICIC

~100ms X2 C

UL SIR HO, AC, ICIC ~100ms X2 C

UL HARQ BLER O&M ~100ms Ni

eNodeB

C

Propagation Delay Thit lp cuc gi, O&M N/A NieNodeB

N/A

UE Tx time difference nh thi trong khi chuyngiao

~50-100ms

NieNodeB

N/A

Ch gii:

1. HO: Handover chuyn giao

2. AC: Admission Control qun l tip nhn kt ni

3. CC: Congestion Control iu khin nghn

4. O&M: Operation and maintenance Hot ng v bo tr

5. ICIC: Inter-cell Interference Coordination - chng nhiu lin cell.

3.3 CC GII THUT C S DNG TRONG QUN L TI NGUYN VTUYN TRONG LTE

3.3.1 Cc gii thut qun l chp nhn kt ni (Admission Control)C ch qun l chp nhn kt ni c vai tr c bn l quyt nh khi mt UE c yu

cu thit lp vt mang kt ni n eNodeB th c chp nhn kt ni hay khng. Hainguyn tc chnh ca c ch ny l:

Bo m rng eNodeB c ti nguyn p ng c yu cu v QoS nu

thit lp vt mang hay kt ni cho UE;

Bo m rng eNodeB c th duy tr mc QoS mong mun ca cc kt ni cn

li trong cell k c khi kt ni mi c thit lp.

V th eNodeB cn phi tnh n cc thng s QoS ca tt c cc UE trong cell vthm c kt ni mi c thit

RRM in LTE_full

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