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CNG NGH LTE :S thnh cng ca cng ngh LTE ph thuc vo 3 yu t:

Sub-carrier: sng mang th cp- Trong h thng OFDM, ph tn s c sn c chia thnh nhiu sng mang, c gi l

cc sng mang th cp (Sub-carriers)

GI (Guard Intervals): l k thut c thm vo mi k hiu ( Symbol ) kh nhiu link hiu OFDM do hin tng tr hon trong qu trnh tri ph

Trong E-UTRA, GI c chn trc mi k hiu OFDM theo mt chu k (cyclicprefix) nht nh. y l k thut c khnng trnh c hin tng nhiu a ngv gip vic xy dng thit bthu t hiu qu cao.

PAPR: ( PeaktoAverage Power Ratio ) : T l cng sut trung bnh SCFDMA : ( single carrier frequency division multiple access ): k thut phn chia tn s

sng mang n FDD ( Frequency Division Duplex ): Phn chia theo tn s song cng TDD ( Time Division Duplex ) : Phn chia theo thi gian song cng

Ti ln SC-FDMA

OFDMA c xem l phng n ti u cho hng DL nhng hng UL th cha cthun li. iu ny l do thuc tnh ca OFDM c t l cng sut nh trung bnh (PAPR- Peak-to-Average Power Ratio) thp, lm nh hng n vic truyn tn hiu ca hngUL. Do , hng UL ca ch FDD v TDD s s dng k thut a phn chia tn s

LTE

OFDMA

SC-FDMA

AntenMIMO

p dng cho ng DL ch FDD v TDD, s dng k thut i

ch QPSK, 16QAM, 64QAM. Cc k hiu (Symbol) c iu chlp v c pht qua cc Sub-carrier trc giao cch nhau lin tip vslng ln

p dng cho ng UP ch FDD v TDD. Cc tn hiu SC-FDMc tn hiu PAPR tt hn OFDMA. y l mt trong nhng l do ch chn SC-FDMA cho LTE. PAPR gip mang li hiu qu cao trongvic thit cc b khuch i cng sut UE, v vic x l tn hiu ca FDMA vn c mt sim tng ng vi OFDMA, do , tham shng DL v UL c thcn i vi nhau. Tn hiu SC-FDMA c t

ra bng k thut tri ph DFT-OFDM (DFT-s-OFDM)

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sng mang n SC-FDMA (Single Carrier Frequency Division Multiple Access) theo chuk

H thng SC-FDMA truyn cc sng mang con tun t ch khng truyn song song,chnh v iu ny cho php PAPR thp m quan trng l tang phsng di ng, t tn

hao pin cho thit bu cui.

SC-FDMA FOR MOBILE COMMUNICATION

Source

encoder modulation N-pointDFT

Subcarriermapping

M-pointIDFT

Add CP