Nghiên cứu giải pháp công nghệ FPGA cho các ứng dụng truyền thông

DAI HOC QUOC
GIA
HA
NOI
Ten ae
tai
Nghien
CLFU
giai phap
cong
nghe
FPGA cho cac
inng
dung
truyen thong.
Ma so: QC 08-12
Chu nhiem
de
tai: Ts.
Nguyin
Quoc Tuan
DAI HOC QUOC GIA HA
Npl_
TRUNG
TAM THONG TIN
THU
VIEN
OOG ^00000^5
Hanoi
2009
1.MUCLUC

1.
Muc luc 1
• •
2.
Bang giai thich cac
chu-
viet tat 2
3.
Danh sach nhiing nguoi tham gia thyc hien de tai 7
4.
Danh muc cac bang so lieu ^
5.
Danh muc cac hinh 8
6. Tom tdt cac ket qua nghien cuu chinh cua de tai 9
7.
BAO CAO TONG KET 10
T.l.Datvande
10
1.2.
Tong quan cac van de nghien ciru
7.3.
Muc tieu va Noi dung Nghien ciiu ciia De tai
7.4. Dja diem, thcri gian va phuang phap nghien ciiu
r
7.5.
Ket qua nghien ciiu
7.6 Thao luan
r
f
1.1 Ket luan va kien nghj

7.8 Tai lieu tham khao
2.
Bang giai thich cac
chfr vi§t
tat:
Ky
hieu
TiingAnh
Tieng Viet
ADC Analog to Digital Converter
ADSL Asymmetric Digital Subscriber Line
AMI Alternate Mark Inversion
ANSI American National Standards
Institute
AOC A Overhead Control Channel
ATM Asynchronous Transfer Mode
ATU ADSL Transceiver Unit
ATU-C ADSL Transmission Unit at the
Central Office
ATU-R ADSL Transmission Unit at the
Remote Side
AWGN
BER
BRI
BRITE
BT
CAP
CBI
CDMA
CDSL

CCITT
CIR
CME
CMF
CO
Additive White Gaussian Noise
Bit Error Rate
Basic Rate ISDN
BRI Transmission Extension
B-Tightness
Carrierless Amplitude/Phase
Modulation
Cross Band Interference
Code Division Multiple Access
Consumer DSL
Consultative Committee on
International Telegraph & Telephone
Channel Impulse Response
Channel Mismatch Error
Conjugate Mirror Filter
Central
Office
Bo bien doi tuang tu - so
Duong day thue bao so bat d
Ma dao dau luan phien
Vien tieu chuan quoc gia cue
Kenh dieu khien dung tieu
di
Che do truyen dan khong
doi

Don vi thu phat (truyen dan)
Don vi truyen dan ADSL
j:
cap dich vu
Don vi truyen dan ADSL phi
Nhieu Gauss, trang cong
tinl-
Ty
le
bit loi
ISDN
toe
do
CO
ban
Mo rong truyen dan ISDN to
Thuat toan phan bo bit chat
c
Dieu che bien do-pha khong
Nhieu giua cac bang
Da truy cap phan chia theo
n-
Khach hang DSL
Uy ban tu van
v6
dien thoa
quoc te
Dap ling xung kenh
Loi
ghcp

kenh khong hop
Bo
Igcguong lien
hop
NhacungcSpdich
vu
CODEC
CP
CPU
CRC
CSA
CS
DAC
DAML
DBO
DC
DCT
DDS
DFE
DFT
DLC
DMB
DMT
DMS
DSL
DSP
DWMT
DWT
ECH
EF

EOC
ET
ETSI
FDM
FEC
Voice Coder / Decoder
Cyclic Prefix
Central Processing Unit
Cycle Redundancy Check
Carrier Serving Area
Cyclic Suffix
Digital to Analog Converter
Digital Added Main Line
Dynamic Bandwidth Optimization
Direct Current
Discrete Cosine Transform
Digital Data Service
Decision Feed-back Equalizer
Discrete Fourier Transform
Digital Loop Carrier
Discrete
MuUi-Band
Discrete MultiTone
Discrete
MuhiScale
Digital Suscriber Line
Digital Signal Processing
Discrete Wavelet Multitone
Transform
Discrete Wavelet Transform

Echo-Canceled Hybrid
Efficiency
Embedded Operations Channel
E-Tightness
European Telecommunications
Standards Institute
Frequency Division Multiplexing
Forward Error Control
Bo ma hoa va giai ma thoai
Tien to vong
Bg
(dan vi)
xii li
trung tam
Kiem tra do du
thira
vong
Vung dich vu song mang
Hau to vong
Bo bien doi so - tuang
tir
Duang day c6 them so
Toi uu bang thong dong
Dong dien mot chieu
Bien doi Cosin rai rac
Dich vu du lieu so
Bo can bang phan hoi quyet dinh
Phep bien doi Fourier rai rac
He thong mach vong so
Da bang rai rac

Da am rai rac
Da phan giai rai rac
Duong day thue bao so
Xii ly
tin hieu so
Bien doi da song con rai rac
Phep bien doi song con
roi
rac
Lai,
khir
tieng vong
Thuat toan hieu suat
ciia
Campello
Kenh boat dong theo kieu nhiing
Thuat toan nang
lugng
chat
ciia
Campello
Vien tieu chuan vien thong chau Au
Hop kenh phan chia theo tan so
Kiem
loi huong
thuan
CODEC
CP
CPU
CRC

CSA
CS
DAC
DAML
DBO
DC
DCT
DDS
DFE
DFT
DLC
DMB
DMT
DMS
DSL
DSP
DWMT
DWT
ECH
EF
EOC
ET
ETSI
FDM
FEC
Voice Coder / Decoder
Cyclic Prefix
Central Processing Unit
Cycle Redundancy Check
Carrier Serving Area

Cyclic Suffix
Digital to Analog Converter
Digital Added Main Line
Dynamic Bandwidth Optimization
Direct Current
Discrete Cosine Transform
Digital Data Service
Decision Feed-back Equalizer
Discrete Fourier Transform
Digital Loop Carrier
Discrete Multi-Band
Discrete MultiTone
Discrete MuhiScale
Digital Suscriber Line
Digital Signal Processing
Discrete Wavelet Multitone
Transform
Discrete Wavelet Transform
Echo-Canceled Hybrid
Efficiency
Embedded Operations Channel
E-Tightness
European Telecommunications
Standards Institute
Frequency Division Multiplexing
Forward Error Control
Bg ma hoa va giai ma thoai
Tien to vong
Bg (don vi)
xir

li trung tam
Kiem tra do du
thija
vong
Vung dich vu song mang
Hau to vong
Bg bien doi so - tuong tu
Duong day c6 them so
Toi uu bang thong dong
Dong dien mot chieu
Bien doi Cosin roi rac
Dich vu du lieu so
Bg can bang phan hoi quyet dinh
Phep bien doi Fourier roi rac
He thong mach vong so
Da bang rai rac
Da am roi rac
Da phan giai roi rac
Duong day thue bao so
Xu ly tin hieu so
Bien doi da song con roi rac
Phep bien doi song con roi rac
Lai,
khii
tieng vgng
Thuat toan hieu suat cua Campello
Kenh boat dong theo kieu nhiing
Thuat toan nang lugng chat
ciia
Campello

Vien tieu chuan vien thong chau Au
Hop kenh phan chia theo tan
s6
Kiem loi huong thuan
FEQ Frequency-Domain Equalizer
FEXT Far End CrossTalk
FFE Feed-Forward Equalizer
FFT Fast Fourier Transform
FIR Finite Impulse Response
FPGA Field Programable Gate Array
FSK Frequency Shift Keying
FSN Full-service Network
FTTH Fiber To the Home
FWT Fast Wavelet Transform
G.DMT The full-rate Recommendation
G992.1
HDSL High-bit-rate Digital Subscriber Line
HDSL2 Second-generation High-bit-rate
Digital Subscriber Line
HDTV High-definition Television
HSF High SuperFrame
HPF High-pass Filter
IBI
Inter-Band Interference
ICl
Inter-Carrier Interference
IDFT
Inverse Discrete Fourier Transform
IDWMT
Inverse Discrete Wavelet Multitone

Transform
IDWT
Inverse Discrete Wavelet Transform
IEEE Institute of Electrical and
Electronical Engineers
IFFT
Inverse Fast Fourier Transform
IIR
Infinite Impulse Responde
ISDN
Integrated Services Digital Network
ISl InterSymbol
Interference
ITU International Telecommunication
Union
Bg can bang
mien
tan so
Nhieu xuyen am dau xa
Bg can bang tuyen tinh huo
Phep
biSn
doi fourier
nhanh
Dap ling xung
huu
han
Mang cong kha lap trinh
Khoa dich tan
Mang dich vu cac

loai
Mang cap quang toi tan nha
Phep bien doi song con
nhai
Khuyen nghi toan
toe
G.99:
ADSL
Duong day thue bao so
toe (
Duong day thue bao so
toe
thu
2
Truyen hinh phan giai cao
Sieu khung
Mach
Igc
thong cao
Nhieu trong bang
Nhieu giua cac song mang
Phep bien doi Fourier roi
rai
Phep bien doi da song con n
Phep bien doi ngugc song
c(
Vien Ky thuat Dien va Dien
Phep bien doi Fourier nhanh
Dap ling xung v6 han
Mang so da dich vu

Nhieu giua cac ki hieu
Lien minh vien thong quoc t
LMSE Least Mean Squared Error
LPF Low-Pass Filter
LT Line
Terminafion
MA
Margin-Adaptive
MIB
Management Information Base
MIMO
Multiple Input Multiple Output
MIP
Million Instruction Process
MCM
Muki-Carrier
Modulation
MF Matched-Filter
MFB Matched-Filter Bound
MRA Multi-Resolution Approximated
MRSE Mean Redundancy Squared Error
MMSE Minimum Mean Squared Error
MSSNR Maximum Shortening
Signal-to-
Noise Ratio
NEXT Near End CrossTalk
NID
Network Interface Device
NT Network Termination
OFDM Orthogonal Frequency Division

Multiplexing
PAM Pulse Amplitude Modulation
PAPR
Peak-to-Average
Power Ratio
PCM Pulse Code Modulation
PDF Probability Density Function
POTS Plain Old Telephone Service
PR Perfect Reconstruction
PSD Power Spectrum Density
PSK Phase Shift Keying
PSTN Public Switched Telephone Network
QAM Quadrature Amplitude Modulation
QMF Quadrature Mirror Filter
Sai so binh phuang trung binh toi thieu
Mach
Igc
thong thap
Dau cuoi
duong
day
Thich nghi du phong
Co so thong tin quan ly
Da loi vao da loi ra
Xii
li hang trieu
lenh
Dieu che da song mang
Bg
Igc

hoa hop
Bien bg
Igc
hoa hop
Gan
diing
da phan giai
Loi binh phuong con du trung binh
Loi binh phuong trung binh toi thieu
Lam ngan
lai
toi da ty so tin hieu tren on
Nhieu xuyen am dau gan
Thiet bi giao dien mang
Dau cuoi mang
Hop kenh phan chia tan so
true
giao
Dieu che bien do xung
Ty so cong suat dinh va cong suat trung
binh
Dieu che ma xung
Ham mat do xac suat
Dich vu thoai truyen thong
Khoi phuc hoan hao
Mat do pho cong suat
Khoa
djch
pha
Mang thoai chuyen mach cong cong

Dieu che bien do cau phuong
Bg
Igc girong
cau phuong
RA Rate-Adaptive
RADSL Rate-Adaptive DSL
RF Radio Frequency
RFI
Radio Frequency Interference
RLSE Recursive least squared Error
RS Reed Solomon
SCM Single Carrier Modulation
SDSL Symmetric DSL (Single-pair DSL)
SDR Software Define Radio
SER Symbol Error Rate
SISO
Single Input Single Output
SF Super Frame
SNR Signal to Noise Ratio
STFT Space Time Frequency Transform
STM Synchronous Transfer Mode
TCM Trellis Coded Modulation
TDM Time Division Multiplex
TEQ Time - Domain Equalizer
TIR
Target Impulse Response
UADSL Universal ADSL
UAWG Universal ADSL Work Group
UEC Unit
-

energy constraint
UTC Unit - tap constraint
VDSL Very high bit rate Digital Subscriber
Line
VNPT Viet nam Post Telecom
xDSL x-type Digital Subscriber Line
WMAN Wireless Metropolitan Area Network
WLAN Wireless Local Arear Network
Thich nghi
toe
do
DSL
thich nghi
toe
do
Tan so Radio
Nhieu tan so Radio
L6i
binh phuong toi thieu di
Ten cua kieu ma sua loi Ree
Dieu che don song mang
Duong day thue bao so
d
DSL mot cap day)
Radio dugc dinh
nghla
phan
Ty le loi ki hieu
Mot loi vao, mot loi ra
Sieu khung

Ty so cong suat tin hieu tren
Bien doi khong thoi gian tan
Che do truyen dan dong bg
Dieu che ma
luoi
Hop kenh phan chia thoi gia
Bg can bang mien thoi gian
Dap ling xung mong muon
ADSL toan cau
Nhom lam viec ADSL toan
c
Rang bugc nang lugng don \
Rang bugc
"tap"
dan
vj
Duong day thue bao so
toe
d
Buu chinh Vien thong Viet n
Cac kieu duong day thue bac
Mang khong day thanh pho
Mang khong day
cue
bo
3.
Danh sach
nhirng ngu-oi
tham gia
thue

hien de tai (hoc ham, hoc vi,
co*
quan cong
tac)
• Chu tri de tai :
Ho va ten : Nguyen Quoc Tuan Nam
O
Namsinh:
12/1953
Chuyen mon dao tgo : Dien tu - Vien thong
Hoc ham, hoc vi: Thgc
sT
Chuc vu: Chu nhiem bo mon He thong Vien thong
nu
O
Cac can bo tham gia
TT
1
2
5
6
Hg va ten
Trang Cong Trung
Vu Xuan Thang
Tran Viet Khoa
Bui Trung Ninh
Hgc vj
Cu nhan.
Ths.
Cii

nhan.
Ths
Chuyen nghanh
Dien
tir
Vien
thong
Dien
tii
Vien
thong
Dien tu Vien
thong
Dien
tir
Vien
thong
Co quan cong tac
Dai hgc Cong nghe,
DHQG Ha ngi
Dai hgc Cong nghe DHQG
Ha noi
Dai hgc Cong nghe DHQG
Ha ngi
Dai hgc Cong nghe DHQG
Ha ngi
4.
Danh muc cac bang so lieu
Bangl:
Kich

thuoc IFFT cho
802.11 sii dung
OFDM
Bang 2 : Yeu
cAu
dung
c6ng
FPGA cho thiet ke thu phat OFDM
5. Danh muc cac
hinh
Hinh 1
Hinh 2.
Hinh 3 :
Hinh
4
Hinh
5
Hinh 6
Hinh 7
Hinh
8
Hinh
9
Hinh
10
Hinh
11
Hinh 12
Hinh 13
Hinh 14

Hinh 15
Hinh 16
Hinh 17
He thong thu phat dua tren MCM dien hinh
Kit FPGA Virtex-4 Xillinx
Software Radio Platform - FPGA Design
IPCore
FFTv3_2 ciia
Xillinx
SDR cho he truyen dan da song mang dua tren OFDM
SDR cho he truyen dan da song mang dua tren DMT
So do nguyen li bg tao du lieu
16-QAM
Diem chom sao thu /phat
So do nguyen li bg dieu che va chen Cp (OFDM)
Dang tin hieu sau khi dieu che va chen Cp
Pho va dang tin hieu sau khi dieu che
So do khoi bg giai dieu che dua tren FFT
So do khoi tien
xii
li tin hieu
I/Q
va tach
d6ng
bg cua OFDM
Thong tin dong bg OFDM
Kien
triic
Cordic
xii

li tuong quan
So
do nguyen li khoi dieu khien
Tin hieu
xii
li dieu khien dong bg
6. Tom tat cac ket qua nghien
ciiu
chinh
ciia
de tai
6.1
Ket qua khoa hoc
•
01
bao cao khoa hgc dang tai tap chi trong
nuoc
6.2 Ket qua
u'ng
dung
• San pham cong nghe:
Phan mam
dinh nghTa Radio (SDR) cho he thong truyen dan da song mang dua
tren
diSu
cha
IFFT/FFT
viat cho FPGA
ciia
Xillinx

- Cho truyen dan da tan roi rac DMT cho cac he thong c6 day
- Cho truyen dan Hgrp kenh phan chia tan so true giao (OFDM) cho cac he
thong khong day
• Kha nang
ling
dung
thue
ta cua cac ket qua:
- Thiat
ka
cac he truyen dan OFDM cho cac mang khong day di dong tha he 4.
- Cho phep ling dung thiat
ka
cho cac mang truy cap bang rgng c6 day khac
nhuADSL2^
6.3 Ket qua dao tao
•
San pham dao tao
- Dai hgc: 01 khoa luan tot nghiep sinh vian Dai hgc chat lugng cao
• Bo xung tai lieu cho giao trinh
- Bo xung mot phan kian
thiic
cho giao trinh giang day Dai hgc
lian
quan
dan
phan
mam
dinh
nghia

Radio - SDR
6.4 Ket qua ve tang
cw&ng
tiem
lye
cho
dcyn
vi
• Ket qua boi duang can bo:
Giiip
cac can bg tang cuong kha nang nghian
ciiu,
tiap can cac phuong phap nghian
ciiu
phan mem dinh
nghia
Radio (SDR) dua
tran
mo phong va VHDL
• Dong gop cho viec tang cuong trang thiat bi:
Khong nhiau
7.
BAG CAO TONG KET
.
;
^
7.1.
Oat
vin d§
Radio dugc dinh nghia

bkg phSn mam
(SDR) la he
th6ng
thu phat
cl
dugc kha nang lap trinh cao cho truyen thong. Trong mot he thong SDR, tat
trong thiat bi khi
xii
li dugc hoan thien
b^ng
phSn
mem. Do vay cac thanh
p
th6ng sii
dung SDR cho phep
linh
dong va la cac giao
thiic
mang thong minh
phan chia
tSn
s6
true
giao (OFDM) va da
t^n
rai rac (DMT) dung cho cac he
cha da song mang (MCM) da tra thanh cong nghe
diau
cha thong dung ch
(ADSL,

802.11/g,
802.16e ).
Giai phap
sii
dung SDR cho FPGA
da
tao ra c
phSn mam
thue
sir
dinh nghia DMT/OFDM, khai thac cac giao thiic mang
dai
kiam de
sii
dung va ma rgng truyan thong
7.2.
T6ng
quan cac
vin
de nghien
CLPU
• Nguyen tac chung
Cac thiet bi
v6 tuyan
kinh
dian
chi
ling
dung cac phan
tir

tuong tu
(Analoj
Ian
thiet
ka
cac
thilt bj
v6 tuyen nay,
chiic
nang
ciia
he trong thiat bi dugc
khong
CO
the thay doi mot
each
de dang. Nha su phat trian manh me
ciia ki
th
hieu
s6
(DSP), day
c6ng
kha lap trinh (FPGA) va cac bg xu li muc dich cl
cho phep ling dung
xii
li tin hieu bang phan
mam.
Cac
diau

nay da nang tha
vuc
''Radio
dugc dinh nghia boi phan
mam
- SDR". SDR c6 tha dugc din]
mot thiat bi, thue chat cac thiet bi nay dugc dinh nghia bang phan
mam
va ho
toan bg lap Vat ly giao thiic mang, c6 tha dugc thay doi thong qua
sir
thay d
mem
111.
Uu diam
ciia
SDR la
sir
thay doi doi vai Radio chi la
sir sira
doi
pi
nau CO
thi chi
siia
doi rat it ve phan
ciing.
Hon nua, SDR bao gom bg xu li
la
noi

true
tiap
voi
cac bg
bian
doi tuong tu - so (ADC) va
bian
doi so - tuan]
Cac bg nay c6 tha noi true tiep vai antenna. Nhu vay, trong cac he thong
SDI
cac tin hieu dugc
thue
hien bang phan
mam
va phan
mam
noi
true tiap
toi ant
Do
sir
han cha
ciia
gia thanh san pham, hieu nang va han cha
ciia
kha na
cac he thong SDR
thue sir
la rat hiem. Tren
thue

te, nhieu he
th6ng
SDR hien
hgp
ciia
cac he bao gom CPU, DSP, FPGA va cac
phSn ciing
chuyan dung. (
nay rat manh. nhung kho c6 tha chuong trinh hoa dugc. Nhieu
ngudi
cho
rS
tran
PC la dich huong tai va nhieu de tai da
thue
hien theo huong do
[2,
3,
hieu nang
ciia
PC lien tuc tang thoa man
yau
cm
ciia
cac
ling
dung
xii
li tin hieu hien dai.
Nhung PC chi voi CPU thi khong

dii da
dap
ling
nhiau
ling
dung do anh huong
ciia
cac
he dieu hanh (OS). CPU voi mot FPGA dua
tran
DSP la he
thdng
SDR
dii
manh
da xii
li
tin hieu va dieu
khian.
• Dieu che da song mang (MCM)
Tat ca cac he thong truyan du lieu
dau
su dung mot kieu cong nghe diau cha nao do
da
ma hoa
dir
lieu so roi
da
truyan. Tai may thu, viec giai diau cha dugc
thirc

hien
da
phuc hoi thong tin goc. Thong thuong du lieu dugc ma hoa bang each doi mot hoac vai
dac tinh cua tin hieu song mang chang han nhu tan so, bian do hoac pha. Mot trong cac
ky thuat nhu tha la tach day du lieu noi tiap thanh mot so cac
luong
dii lieu song song
(phan tu "song" mang con). Nhiing phan
tir
"song" mang con nay dugc
diau
cha riang
biet bang
each
dung mot ky thuat bian dieu (diau che) toe do thap va dugc truyan di song
song nho cac phan
tii
"song" mang voi cac tan so khac nhau. Mac du cac phan
tii
"song"
mang con chuyen
dir
lieu mot
each
doc lap voi toe do thap nhung thong lugng ggp
ciia
tat ca cac phan tu "song" mang con c6 tha cao. Vai gian each hgp ly, c6 tha dat cac phan
tii
"song" mang con rat gan nhau ma khong gay nhiau
Ian

nhau.
Da
tai dua ra so do khoi mot thiat bi thu phat MCM thong thuong trong hinh 1 (ma
diau
cha DMT hay OFDM la mot trong cac
ling
dung
ciia
MCM). Cac
chiic
nang
ciia
bg
thu phat MCM c6 tha dugc chia thanh 2 loai: ma hoa kanh va
diau
cha. Ma hoa coi nhu
la tian
xii
ly truoc khi cac song mang con doc lap nhu nhau dugc
diau
cha.
Diau
che
MCM la loai diau cha cac song mang con doc lap,
sii
dung bian doi Fourier ngugc va
chen dai bao ve. Trong khi do ma hoa kanh eo tha thay doi dang ka giiia cac chuan,
DO lieu
^ Xao tron
Ma hoa

QAM
IFFT
Tien
Xi> If
DO'
lieu
Giaixaotronc
Giai
ma
QAM
^
Bu
trCr
L/oc
luong
kenl*
FFT
T
CORDIC
Dong bg
khung
r
Tu*
tyong
quan
Kenh
Tien
Xix
If
^

Hinh 1
He thong thu phat dua tren MCM dien
hinh
11
Co 3
vSn da
phai lam
da
thiat ke SDR cho mot he
thdng
thu phat dua
tran N
tian la
vSn
de dieu che/giai dieu che dua
tran
MCM, van
da thii
hai la tian xu
bao
d6ng
bg nhip va
ddng
bg khung giiia hai he thong thu va phat dua
tran
MC
da
cuoi Cling la ma hoa
kanh
va

thii
nghiem danh gia kat qua,
• Dieu chi da tan rai rac(DMT)vd phan chia
thn
so
true
giao (OFDM)
Diau cha dua
tran
MCM
-
DMT/OFDM chinh la
diau
che cac phan
tii
song
Mot hoac mot so bit
tii buoc
ma hoa
kanh
dugc gan cho moi mot phan
tii si
mang con roi se dugc
diau
cha bang each
sii
dung mot ky thuat don gian chan]
khoa dich pha (phase shift keying - PSK) hoac diau cha
bian
do cau phuong ((

bit dung cho moi phan
tii
song mang con se phu thugc vao ky thuat dieu ch
(hoac xac xuat bit loi mong muon khi truyan). Vi du, QPSK se doi hoi 2
bil
phan
tii
mang con. So lugng cac phan tu song mang con (hay loai dieu cha) se
dinh bang giao thiic hoac chuan dugc
sii
dung.
Diau che DMT/OFDM dua
tran
thuat toan bian doi ngugc Fourrier roi rac
theo thong thuong thi
sir
dung thay bang giai thuat bien doi ngugc Fourier nhar
iDFT la mot chiic nang c6 loi vao la chuoi dii lieu bieu
dian
cac tan so dugc
day du lieu do va tra lai mot tap cac he so dugc tim thay trong du lieu do biau
thai gian. Bg dieu che DMT/OFDM cho
thSy
ca FFT va IFFT
dau
c6 cung
thuac dugc ki hieu
-
Njjf.
Day chinh la so lugng thong tin loi vao va thong tin

Ic
tao ra
tii
giai thuat bian doi Fourier thuan hay ngugc va la mot tham so
thiel
trgng doi vai cac he DMT/OFDM.
T6c
do mau
ciia
he va so lugng thong tin
cii
bien doi Fourier
Njj,
xac
djnh
khoang each giua cac
ph§n tii
song mang con.
U
tuong doi voi DMT/OFDM vi no c6 cac
ling
dung phan ciing va
phSn
mem hit
vi no tao ra cac phan
tii
song mang con dugc gian each mot
each
ly tuang.
Ca

mang con
tran
thue
ta
phai la
true
giao khi
chiing
dugc gian
each,
do vay
chii:
gay nhiau
ISn
nhau. IFFT tim
thSy
trong OFDM coi du lieu
phSn tii
mang cor
bien dieu la loi vao va tao ra du lieu
chu6i
thai gian tai
16i
ra. Tin hieu mien
nay se
chiia
tat ca tong
ciia
tung tin hieu phan
tii

mang con
Njf,.
Goi [xXll la
bieu tuong
dir
lieu
phiic
dugc truyan nho MCM thi
,V-1
.In
A„ =
2^x{m)e
•'•
=
DFT{x(m)} (n
voi
m.
n
=
0. 1
h'-l.
Ngugc lai ta c6
^^-
^Z^-"^'''''""
=
iDFT[X„}
(2)
•^*
m=0
Bieu thiic (1) cho phep MCM

sii
dung IFFT de dieu che , con
biau
thiic (2)
sii
dung FFT
dugc sii
dung
da
giai
diau
cha trong truyen
din
MCM.
Vi biau
tuong
OFDM
chiia
nhiau phan
tii
song mang eon biau dian nhiau bit
nan
khoang
ciia
bieu tuong OFDM nay c6 the tuong doi dai. Diau nay lam giam
nhilu
xuyan
biau
tuong
(ISI)

gay ra boi
sir
phan xa da duong tai may thu OFDM. Phan xa da duong
xay ra khi mot tin hieu phan xa cac giao dien khac nhau dge theo cac duong dan boi tu
may phat
dan
may thu. Vi bat ky duong dan nao trong so bi phan xa cung se dai hon
duong dan
true
tiap tu may thu den may phat
nan
cac tin hieu da duong dan se bi cham
tuong doi so vai tin hieu duong dan true tiep va se chong voi
biau
tugng OFDM tiap
theo.
Do khoang biau tugng DMT/OFDM dai
nan
lugng phan chong
Ian
c6 tha nho so
vai mot so do diau cha chuoi noi lugng chong
Ian
do c6 tha bao
phii dan
vai
biau
tugng
ngan. De loai bo hoan toan ISI, mot dai bao ve (Cp) can phai dugc chen vao khi bat dau
moi

biau
tugng DMT/OFDM. Trong khoang bao ve do, may thu c6 tha van nhan dugc
cac phian ban bi cham cua biau tugng truoc gay ra. May thu khi do se bo qua phan bao
ve truyan tin. Trong nhiau he DMT/OFDM, dai bao ve nay la
sir
keo dai tao ra tuan hoan
ciia
biau tugng DMT/OFDM.
Da
dai bao ve tao ra tinh tuan hoan thi dai bao ve la ban
sao
ciia
phan cuoi cung
ciia biau
tugng DMT/OFDM dugc dinh vao phan bat dau
ciia
chinh biau tugng do.
Nhu vay khoang thoi gian
eiia
mot ki hieu OFDM/DMT la
T^
=
(T^
+
T^,
(voi
To
la khoang thoi gian
A''
mau IFFT va

Ty
la khoang thai gian v mau CP) se
Ion
hon nhiau
thai gian mot ki hieu dugc
diau
cha trong he thong don song mang
Cac phan xa da duong dan
cflng
c6 tha lam suy hao hoac bang khong tai cac tan
s6 khac nhau trong mot
biau
tugng MCM. Diau nay c6 tha anh huong toi mot hoac nhiau
tan
s6
trong khi khong tac dong gi
dan
cac phan
tir
mang con khac. De do cac
miie
suy
giam nay va cac
diau
kien
kanh
khac, thong thuong
nguoi
ta chen cac phan
tii

song mang
con
thii
nghiem vao trong bieu tugng OFDM/DMT (ggi la
pilot-subcarrier).
Vi cac bieu tugng pilot song mang con la da biat doi voi may thu
nan
may thu c6
tha
sii
dung cac pilot
da
uac
lugtig
cac dieu kien kanh qua tat ca cac cac phan
tii
mang
con va
bii
dap mot each thich dang. Diau nay con dugc ggi la biau tugng pilot ho trg dieu
cha
(pilot symbol assisted modulation - PSAM)
13
Trong cac he MCM kiau khung, moi khung thuong bit
dhu bkng
nu
nao do cac biau tugng mao dau. Co nhiau ly do cho viec do, mot trong so cac
may thu bugc phai c6 kha nang bat dugc vi tri bat dau
ciia
mot

Idiung
truyan
•
chinh cac mach kiam soat do
Igi ciia
no. May thu cung c6 tha dong bg hoa v
ciia
no va tinh chinh tan so dong ho
ciia
minh
da phii hgp
vai may thu. Cuoi
tugng mao dau cho phep mot so du doan uac lugng kanh va thue hien can ban
Da
cai thien hieu suat
ciia
truyan thong dua
tran
MCM, he thong phai
si
so loai ma hoa. Phuang thiic hieu chinh
16i
(FEC) can chen mot do du
thm
dong
dir
lieu
da
cac loi gay ra do phading hay nhiau chi vao mot vai song
m,

CO
tha dugc
siia
chua bang
each sii
dung du lieu khong loi tu cac song
manj
Hieu suat
ciia
mot vai kiau ma hoa c6 the dugc nang
lan
trong MCM nho bu
Xen ke xao trgn cac bit
dir
lieu sao cho cac bit lian
tiap
trong luong du lieu
du
cac song mang con khac nhau trong cac biau tugng
ciia
MCM. Diau nay eo n
loi nhom trong cac song mang con lian tiep nhau se khong bi xay ra nhu trong
day du lieu khong dugc xen ke. FEC la mot trong cac phuong thiic ma hoa
trgng nhat doi voi truyen dan dua
tran
MCM. Nhung vin
dk
khac nhu: c6
the
xao trgn de lam trang cac luong du lieu, nen du lieu de giam kich thuoc cua do

va tao khung de djnh dang va them thong tin de
kiam
soat cac
Iu6ng
du lieu
dugc
thue
hien
• Thiet
ki
Muc dich
ciia da
tai la thiat
ka
mot he th6ng thu phat dua
tran
da song :
phuang thiic diau cha cua DMT/OFDM. Thiat
ka
nen
h6
trg cac giao thiic hie
CO
trong tuong lai do vay giai phap SDR la phu hgp.
He thong thu phat dua
tran diau
che da song mang thoa man:
(1)
Dieu cha / Giai diau che dua
tran

IFFT/FFT vai N
=
64
(2)
Ma
hoa
16-QAM
(3) Cung cap Cp dam bao
d6ng
bg giua tram thu va tram phat
(4) Cung dp khoang bao ve (mo rgng vong)
dilu
khian.
(5) Co
kha
nang linh boat
Thiet ke trinh bay a day se dat dugc muc tiau nay. Hon nua, da tai se cung
mem kiem soat
tran
cac thong
s6
nhu la kat qua cua
da
tai. He
thdng diau
cha h(
thong
IMHz
cho DSL, khong rgng hon so voi
1.14MHz

cung cap boi ADSL th
Giao dien CPU / FPGA dua
tran
Xillinx 8.2i va cac
diau
che DMT ho trg ca hai khung
hinh dua tren giao thiic va dong.
Dieu cha cac song mang con dugc kiam soat doc lap va c6 tha dugc thay doi lian tuc
giiia
cac ky hieu DMT. Khoang bao ve cung c6 the dugc thay doi
tran
mot
biau
tugng so
vai biau tugng eo ban. Cuoi cung, bang
each
v6 hieu hoa cac song mang
con,
phan
mam
CO
the thay doi mot
each
c6 hieu qua
kich
thuac cua IFFT va tao khong lian tuc cac dang
song
Hinh
2. Kit FPGA Virtex-4 Xillinx
a) Nen tang thiet ke

Phan
mam
Xillinx
ISE
8.2i xac dinh cho phan
nan
kit FPGA Virtex-4 Xillinx dugc
chi ra trong hinh 2. Kit nay bao gom c6 mot bg Xilinx XtremeDSP phat trian san xuat
bai Nallatech va mot thu phat radio 2.4GHz san xuat boi Fidelity COMTECH,
Inc
XtremeDSP. Cac bg phat trian tinh nang Nallatech Benadda Pro PCI/USB bao gom mot
Virtex-4 FPGA,
16
MByte cua RAM va hai bg A/D va D/A chuyan doi.
Nallatech da cung cap mot so vi du mau thiat
ka
FPGA c6 tha dugc
sir
dung voi cac
kit XtremeDSP. Mot trong nhiing thiat
ka
la mot giao dien don gian cho
FFT/IFFT
voi
PCI bus. Khi khao thiat
ka
nay,
da
tai da dua vao va phat trian mot
nan

tang ca ban
sii
dung SDR voi ngon ngu VHDL va Xillinx Simulator
|121,
Minh hga cac tinh nang
ciia
Virtex-4 de thiet
ka
SDR dugc tha hien trong hinh 3.
Truoc khi
truyln,
du lieu truoc hat dugc
luu
tru trong hai day
ciia
bg nho thuong c6
tran
kit FPGA. Bg nha nay c6 dung lugng
512K
byte 32 bit loi vao va c6 tha dugc
sii
dung trong hai
each:
no c6 tha boat dong theo
kiau
FIFO don gian giua giao dien FIFO
va phan con lai
ciia
duong truyan hoac la no c6 tha nho dem du lieu trong bg nho
r6i

sau
15
do kich boat noi dung trong buffer
da
truyan
din.
Du lieu dugc dugc
viat
v;
theo chu trinh va nhip
diau
khian
ciia
bg
dilu
cha (IFFT)
r6i
dugc dge ra
khoi 1
mot bg diau khian dge, bg
diau
khian
dge
don gian diau khian nhip
dge,
so c
giua cac lan
dge
tu bg nha.
Du lieu dugc sinh ra do dge bg nho (MEM) dugc

giii din khSi
logic tr
la nai ngi suy du lieu l6i
ra.Viec
ngi suy dii lieu la
rlt
quan trgng, tai do mg
vao se tao ra nhiau
mlu
l6i ra, hoac khi
nhilu mlu
dugc dong goi thanh vao
ti
bit (tuong ling mot
mlu
du lieu c6
1
chu ki may
16i
vao se dua ra
I
mau keo c
chu ki may).
Jtag
Mem
AD
D/A
Hinh
3 : Software Radio Platform - thiit ke tren FPGA
Cuoi cung, mau tin hieu dugc ghi vao bg bian doi so - tuong tu (DAC). Du

khong phai la muc
tiau
thiat ke
ciia
de tai do do
tran thue ta
no dugc miau t
duong noi giiia tram phat va tram thu. Tin hieu nhan dugc tai may thu dugc
1
dua toi bg bian doi tuong tu - so (ADC) . Khoi nay se gui du lieu loi ra toi
be
Chiic nang
ciia
bg tian
xii
li la phan tich va xac dinh tin hieu dong bg khung,
1
to vong Cp, tach ra tin hieu
phiic
(I/Q) va xap thang hang chiing. Tin hieu
ti'
tha bi v6 hieu trong
truong
hgp mot hoac ca hai
ciia
cac
kanh
dau vao
giii
toi

1
toe"
CO
van da. Khoi giam
toe
don gian loai bo di mot so phan cua cac mau
dai
nay sau do dugc nha dem trong mot FIFO lan ma tai do no cho dgi mot phan
boat DMA chuyan ra bus PCI.
b)
Khao
sat
thiet
ke
Da
thiat ke mot he truyen dan da song mang (MC) tren kit FPGA, da t
may tinh PC
dii
manh de tinh toan thiet
ka
va chay mo phong, cac kit
VPGA
dii
manh c6 kha nang
thue
hien cac duong
6ng xii
li tin hieu so (DSP) eo ban. Vi tha he
thong dugc thiet
ka

c6 tha chay hoan toan
tran
may tinh PC hoac hoan toan
tran
kit
FPGA hoac c6 the chay lai gep ca
tran
PC lan
tran
kit FPGA
Mac du chiic nang tu kiem tra khong dugc
sii
dung o trong bao cao nay
ciia
de tai,
nhung
da
tai ciing da tao mot giao dien de kiem soat cac boat dong he thong dugc thiet
ke trong cha do chay lai gep.
Mot trong nhung muc tieu
ciia da
tai la cung
c4p
mot ca so giai thuat SDR
da
c6
tha dong bg giua may thu va may phat da song mang voi bang tan rgng
da
c6 tha kiam
soat that nhieu tian trinh phat khi c6 tha.

R6
rang la
da
dat dugc nhu vay thi kha nang
tinh toan phai manh, bang thong (toe do) bus vao ra (I/O bus)
ciia
he phai
dii
lan va nhu
vay cac bg ADC hay DAC cung phai c6 toe do cao. Hon nua, khi can
cii
vao su can doi
giua viec lap trinh SDR voi viec thiat
ka
phan ciing thi
da
tai mong muon tang ty trgng
cang nhiau phan
mam
cang tot.
Doi voi MCM, hai van
da
quan trgng can dugc luu y: Thuat toan
bian
doi
FFT/IFFT, do la mot trong nhung thuat toan so quan trgng nhat va each dua du lieu I/O
cho he thong dua
tran
MCM.
Da

hiau dugc cac
yau
cau doi voi MCM, chiing toi chay
mot so chuong trinh chuan
sii
dung FFT/IFFT don gian c6 san
da
khai thac va so sanh
doi chiing Hinh 4 chi ra IPcore FFT/IFFT cua Xillinx cho cac kit Virtex
IlPro,
Virtex4
©FFTv3_2 (XilinxFast Fourier
Transfer
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00060000055
17
Chuan 802.1 la
sii
dung dieu cha OFDM c6 khoang
each
giua cac
so)
0,3125
MHz va thoi gian keo dai
1 biSu
tugng la
3,21
giay. Trong khi do ch
su dung
dilu
che DMT c6 khoang
each
giua cac song mang con bang
4.134K
Rian
keo dai
biau
tuang la 0,125 giay.
Da
dan gian khi tim
kiam
giai thuat,
d
nh4t

thiat
thue
hien mot
chuAn
MCM theo mot he nao c6 san,
dc tai gia dii
dieu cha
IFFT-64
(16 bit) vai cac song mang con c6 khoang each la
25,6KI
gian keo dai
biau
tugng bang 0,500 giay.
Bang
1
dual day cho thay anh huong
ciia
kich thuoc IFFT vao thoi gia
cau
ciia ling
dung MCM.
Da
duy tri mot khoang thai gian biau tugng MCM
t6c
do
l4y mlu
phai tang so vai kich thuac IFFT. Kich thuoc IFFT hoac bang
chinh
bkg s6
lugng dii lieu no tao ra. Tuy nhian CPU cac may tinh PC thu

tha theo kip vai
yau du biln
doi IFFT thai gian thue kich thuoc
Ion
hon 128
ciia
no thuong c6 thong lugng (theo tai lieu ly thuyat)
bang
133M b/s vi tha
theo kip voi cac kich thuac nho nhat (64)
ciia
IFFT
thii
nghiem
Kich thuac IFFT
64
128
256
512
1024
Toe
do bus Mb/s
133
266
522
1024
3128
802.11
Mb/s
80

160
320
640
Bang
J:
Kich thuac IFFT cho
802.11
su
dungOFDM
Do hieu nang
ciia
CPU lian tuc tang nho
xii
li duong ong, cac CPU da
core,
triple core ). Cac kit FPGA tich hgp DSP vao bg vi
xii
ly vai toe do
cang cao. Nhu vay mot so rang bugc
vh
kich thuac IFFT cung se dugc giai q
each phan
viing
thiet ke chinh xac giiia phan
mam
va
phSn
ciing, cac
yau
du \

va thong lugng 1/0 c6 tha dugc giam bot |9|.
nQC08_1
File Edit View Simulation Format Tods Help
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Generator
B

S
6 a
Resource
Estimator
100%
o
ode45
n
Scope
/^.
Hinh
5: SDR cho he truyen dan da song mang dua tren OFDM
Hinh 4 va hinh 5 cho so
d6
thiet ke SDR cho he truyan dan da song mang dua
tran
OFDM va DTM. Thue ra ve nguyan
tSe
hai he nay khong khac nhau nhieu do do trong
khuon kho bao cao
da
tai chi trinh bay cho he truyen dan MCM dua
tran
OFDM.
c) Thiet ke bo phat
May phat truyen MCM
thue
hien cac chiic nang thao tac bit nhu phan chia khung
(dinh khung), ma hoa, xen ke xao trgn dii lieu, phan chia cac song mang con
da

dieu cha
(IFFT) va cuoi cung la chen dai bao ve (tian to cong Cp). Day la cac chiic nang co ban
nhat trong mot may phat MCM dam bao viec truyan dii lieu. Cac chiic nang khac c6 tha
dugc phat trian dua
tran
cac chiic nang co ban nay
da
tang do tin cay va hieu nang truyen
tin giiia thu va phat.
Cac vi du
tran
day voi ADSL hay 802.1 la cho thay, cac giao thiic khac nhau co
tha
CO
each dinh khung hay kich thuoc khung dii lieu khac nhau, each ma hoa dii lieu
dieu khian loi khac nhau va
kiau
tian to hay hau to rat khac nhau, nhung cuoi cung chiing
dau
chia cac khung thanh cac song mang con va
bian
doi IFFT
tran
chiing.
Da
giam bat
bang thong duang truyen, cac bg ma hoa dugc
sii
dung nham anh xa mot nhom bit sang
y

-s
f
'
^
1 biau
tugng
mien tan so - Tuy thuoc vao chat
lugng
duang truyan (SNR) ma
each
ma
hoa dugc
lira
chgn QPSK,
16-QAM
hay 64-QAM
Da
tai su dung
16-QAM
de giam
thieu cac loi sinh ra cho he thong khi truyan tin va do vay bang thong I/O bus giam he so
4.
19
Fie Edt
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D cf
y
a

® I
v^
^ t
4500
Notmal
mm®^
i:-!
i
ft
Bns ®
K
System
Resource
O«neraor
Estimator
Ready
DMT
QC08-
12
Scope
100%
RxedS
Hinh
6: SDR cho he truyen dan
da
song mang dua tren DMT
Bo phat chia thanh 2 khoi eon i) khSi phat tin hieu
16-QAM nhim dh
eh
kiem tra he thong va

//;; Ichoi
dieu che
(IFFTva
chen Cp).
i) Khoi phat tin hieu
16-QAM:
Dung
da
gia lap du lieu
16-QAM
cho (
kiem tra dugc chi ra trong hinh 7. Khoi phat tin hieu
16-QAM g6m
2
pi
nhau, tao ra tin hieu chom sao I/Q nha phuang phap anh xa. Du lieu
nj
dugc tao nha may phat gia lap
nglu
nhian. Du
lieu
nay dugc coi la dia c
dinh du lieu chom sao
16-QAM
dugc chiia trong bo nha ROM.
Da
phi
yau
cAu
bian

d6i
IFFT/FFT, mot chu ki
mlu
du lieu chom sao
16-QAM
dai trong 4 chu ki may.
De dan gian he th6ng nhung
vIn
tang tinh tu nhian cua
chu6i
du
li
nang cao kha nang phat hien
ddng
bo giua may thu va may phat
d6ng
tho
so b,an do dinh trung binh (PAPR), thay vi viec xao tron
dCr liau da
tai su
may phat g.a ngau nhian co gia tri
'"gieo
c§y"
(seed) ban
d4u
khac nhau.
Tin hieu cac diam chom sao
16-QAM
thu duac qua Xillinx
Simulc

ch. ra trong hinh 8(a). Cac tin hieu nay co tinh tu nhian cao dam bao gia
mau Ian can bat ki c6 gia tri khac nhau trong
chuSi
du liau dai
-^
2500 m
he thong phat va thu de thue hien dong bo.
[!]
QC0B_2/Genl/Q/QAM_I
*
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til d
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1
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,/
FTinh
7:
Sa
do nguyen
li
bo
tgo
du
lieu
16-QAM
ii) Khoi dieu
che: So do
nguyan

ly bg
diau
cha
dua
tran
IFFT
va
chen
Cp
dugc
chi
ra trong hinh
9. Bg
dieu cha dua
tran
iFFT-64 dugc viat dua
tran
ngon ngii VHDL
CO
tha
nhiing
vao
Xillinx Simulator
da
thue hien thiat
ka
he
thong
va mo
phong.

iFFT-64
dua
tran
VHDL dugc
kiam
tra va so
sanh voi Ipcore
ciia
Xillinx Blockset
tran
MatLaB 2006. IFFT dugc thue hien theo giai thuat
Cooley-Tukey
(truong
dii
lieu 16 bit)
sao cho
moi phep
bian
doi
cap chuoi
dii
lieu
roi rac loi vao
xn_r
=
{xn_ro,
xn_ri
,
xnj-^^}
xn_i

=
(xnjo,
xn_ij

,
xnj^sj
sinh
ra
cap
day dii
lieu
loi ra
xk_r =
{xkj-Q,
xk_rj
.
xkj-^^}
xkj
=
{xkjo,
xkji
,
xkj^sj
Moi phep
bian
doi
chiam khoang
hon 200
lenh may.
Da

dam bao dii
lieu
vao ra
lian
tuc, dii
lieu
loi vao
dugc
nho
dam
loi vao cho
xii
li
va nho dem loi ra cho
truyen
din.
Moi dii
lieu chiam
4
nhip lenh
may do do
toe
do dii
lieu
loi vao
bSng
t6c
do dii
lieu IFFT
loi ra

(Pipelined Stream
I/O
mode).
So
mau
dii
lieu trong
mot
khung
16i
vao bang
so
mau
dii
lieu trong
1
khung
loi ra sau
khi bian
doi
iFFT.
21
-}
Disp
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••
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••
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-•
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:
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••
•
••
••
••
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••
FTinh
8a: Diem chom
sao
phat
Hinh
8b: Diem chom sao thu
Cac
kh6i
chiic nang khac
nhu
RAM FIFO,
bg
dam
"Counter"
,
cac

"Delay"
hay
khoi
so
sanh
"Relational",
bg
cong "Adder"

dau
dugc
vii
VHDL
va
nhiing vao Xillinx Simulator hoac
co tha lay
cac khoi chiic nang
ciia
Xillinx Blockset de thue hian.
f!lQC08_l/Mod
Fie
Edit View Simuladon
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D
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Id
.1
> ^

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iNmr^nr S
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xn_r« >4<_(t
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done
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FFT v3
2
din
dout
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full

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63
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FIF01
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100%

'od<
////i/;
9:
Sa dS nguyen
li
bo
di^u
ch^
va chen Cp (OFDM)
Moi luong du lieu loi ra IFFT hay ggi la cac biau tugng
{Xk_re,
Xkjm)
dugc
xii
li nhu nhau do vay se co 2 khoi nhu nhau, song song
da tiln
xu li tin hieu
truac khi dugc truyan dan. Hai bg nho RAM FIFO se dugc
diing
da nha dem dii
lieu nham cho phep chuyan doi
t6c
do (thay doi thai gian keo dai cac bieu tugng)
sao cho loi vao FIFO eo toe do thap (thoi gian keo dai biau tuong dai) va loi ra
FIFO CO
toe
do cao (thai gian keo dai biau tuang
ngSn)
de thua 1 khoang thoi
gian chen Cp. Do chiau dai Cp dugc chgn la 16

mlu d6i
voi biau tugng IFFT-64
do do
toe
do chuyan doi phai thoa man ty so:
(16+ 64)/64
=5/4
Chuyan doi toe do dugc thue hien nho
ki
thuat UpSampling lam ngan thoi
gian keo dai 1 mau va DowmSampling
da
keo dai thoi gian keo dai 1 mau. Nhu
vay
da
tao khoang trong chen Cp, moi mau dii lieu dugc co lai theo ty so 4/5.
Hinh 10 duoi day cho hinh anh mo phong qua trinh chen Cp cho cac biau tugng
truac khi dugc truyan dan.
Hinh
JO:
Dang tin hieu sau khi dieu che va chen Cp
23