ĐA
̣
I HO
̣
C QUÔ
́
C GIA HA
̀
NÔ
̣
I
TRƯƠ
̀
NG ĐA
̣
I HO
̣
C CÔNG NGHÊ
̣
LƯU VĂN HOAN
H Ni - 2011
-OFDM
2011
n:
-OFDM
:
:
: 60 52 70
i
ii
T iii
iv
vi
viii
ix
x
1:
-OFDM
2.1.
-OFDM - 7 -
2.1.1.
- 7 -
2.1.2.
- 8 -
2.1.2.1.
- 9 -
2.1.2.2. 10 -
2.2. 12 -
2.3.
14 -
35 -
3.2.
39 -
3.3. 47 -
3.4. 52 -
4:
1.1.
. - 2 -
1.2.
2.3.
-OFDM. - 9 -
2.4.
-OFDM. - 9 -
2.5.
-OFDM. 11 -
2.6.
-OFDM. 11 -
2.7.
. 16 -
2.10. G. 19 -
2.11. . 21 -
2.12. 1. 22 -
2.13. 2. 22 -
H2.14. 3. 23 -
2.15. 4. 23 -
2.17.
. 26 -
2.18. = 0.04 % . 27 -
2.19. = 0.5 % . 27 -
2.20. = 1 % . 28 -
2.21. = 0.1%. 28 -
2.22. AWGN khi CFO = 2%. 29 -
2.23. 1 khi CFO = 0.1%. 29 -
2.24.
. 38 -
3.5. 3
. 38 -
3.6. 4
nhau. 39 -
3.7.
3 4. 42 -
3.13.
. 46 -
3.14. = 0.04% 0.5%. 47 -
3.15. = 0.1% 2%. 48 -
3.16. = 0.1%,
(),
(). 48 -
3.17. m sao trên kênh AWGN khi CFO = 2%,
(),
= 2 %. 51 -
3.23. , CM3, CM4
= 2 %. 52 -
3.24.
1. 21 -
2.6. . 25 -
ng 3.1. . 39 -
3.2. 1. 40 -
g 3.3.
. 41 - ix
- Rao
5
DSS
Direct-Sequence Spreading
6
ECMA
European Computer Manufactures
Association
Mean Square Error
12
OFDM
Orthogonal Frequency-Division
Multiplexing
13
PAM
Pulse Amplitude Modulation
14
PHY
Physical layer
PHY Service Data Unit
18
TFC
Time-Frequency Code
-
19
UWB
Ultra-Wideband
B
20
WPAN
b
b
b
arg .
.E
(.)Var
(.,.)f
Re .
Im .
g
(UWB)
1960
,
.
1990,
(FCC) cho UWB.
,
-10 dB
[1].
: 3.1 GHz
10.6
.
1.1.2.
,
.
:
( ),
( )
(
).
(
2
- 2 -
:
,
.
1.1.
( 5
10
) 100
- 3 -
20 m.
(WUSB)
(PC) i,
(1.3). (a).
.
(b).
(
) (
).
1.4. : (a)
(b)
[1].
(pico second).
.
(time-hopping)
(DSS). ,
.
,
thu
.
,
UWB
3.1
10.6 GHz th
(subband).
500 MHz theo
.
(OFDM),
.
.
,
,
. a
802.15.3
WPAN
(ECMA) -368.
1.2.
:
,
(Carrier Frequency Offset - CFO),
(Carier
Frequency Offset CFO)
kênh UWB. ,
(CFO)
. Tuy nhiên, c
,
-
(Maximum
Likelihood ML) [2].
.
2
,
. N,
,
2
(PS) trong
,
.
MB-
C
3. Li [6]
(Best Linear Unbiased Estimator BLUE)
C
-OFDM. Li
con,
1 -OFDM.
. Debarati Sen [7]
C
c so
[17].
.
1.4.
-368,
802.15.3a.
.
.
,
.
3 -OFDM.
lu (
)
.
theo,
MATLAB .
4
-368 [10]
(PHY)
(MAC) cho
(WPAN),
14 (subband),
528 MHz
2.1.
, 12
(1
12)
4 (band group),
3 .
2 (13 14) .
9, 10 11 ,
2.1.
[10].
f
c
n
b
2.1
. 2.1 .
f
c
(n
b
) = 2904 + 528 x n
b
(MHz),
MHz
3960
MHz
4488
MHz
5016
MHz
5544
MHz
6072
MHz
6600
MHz
7128
MHz
7656
MHz
8184
MHz
8712
MHz
9240
MHz
9768
MHz
10296
MHz
- 8 -
2.1.
(MHz)
(MHz)
(MHz)
1
1
3168
3432
3696
2
3696
3960
4224
3
4224
4488
4752
2
4
4752
5016
8976
12
8976
9240
9504
5
13
9504
9768
10032
14
10032
10296
10560
6
9
7392
7656
7920
10
7920
8184
8448
11
8448
8712
8976
2.1.2.
.
-
(TFC) . 2.2
[10].
2.3 2.4
-OFDM.
chung, :
.
(bit interleaver),
(constellation mapper),
T
ZP
T
SYM
(ns)
3168
3696
4224
4752
#1
#2
D#3
T
FFT
(MHz)
Symbol 1
Symbol 2
Symbol 3
Symbol 4
Symbol 5
.
2.3.
MB-OFDM.
2.4.
MB-OFDM.
2.1.2.1.
n
(data scrambler).
bit .
,
.
PLCP
header
QPSK/DCM
mang pilot,
,
mang null
& IFFT
(t)
X
l
(0)
X
l
(N
FFT
-1)
x
l
(0)
x
l
(N
FFT
-1)
Im{x
l
(n)}
X
l
(k)
RF
OLA
CP
Viterbi
,
x
l
(n)
- 10 -
(convolution encoder)
(puncturer).
(SNR) . Khi
,
,
. ,
Viterbi (Viterbi decoder)
.
.
(bit interleaver).
,
.
,
.
200
Mbps,
.
320 Mbps,
.
.
,
(frequency-domain spreading) trong 1 (time-domain
spreading) qua 2
.
122 con
128 ,
100 , 12 hoa tiêu, 10
3
(TFC)
.
x
l
(t)
l
x
l
(n)
,
x
l
(t)
(up-convert)
- 11 -
(mixer)
ic,
,
ic,
T
SYM
= 312.5 ns,
T
ZP
.
(frequency synthesizer) 3
ic,
,
. 2.5 2.6
BPF
PA
1,c
2,c
3,c
TFC
Re{ ( )}
l
xt
1,c
2,c
3,c
Cos
Sin
- 12 -
2.2.
K UWB ,
. ,
,
,
,
7.5 GHz, nên
133
802.15.3a v
UWB.
:
,
(LOS).
4
(channel model CM),
CM1, CM2, CM3
CM4,
(LOS) hay
(NLOS) .
.
2.2. .
Kênh
CM1
CM2
CM3
CM4
(m)
0 4
0 4
4 10
10
LOS
NLOS
NLOS
NLOS
i.
- {
i
l
T
} l i.
- {
i
lk,
}
k
trong l.
- {X
i
}
i.
0
= 0,
l
l,0
= 0.
,
Poisson,
11
exp|
llll
TTTTP
,
l > 0 (2.4)
lkklklk
p
),1(1),1(,
exp|
,
k > 0 (2.5)
2.7.
-V
lklkl
hay
20
,
21,
10
nn
lkl
lk
(2.7)
n
1
),0(
2
1
n
2
),0(
2
2
,
(2.8)
, T
l
l
0
(),
1
,
lk
p
/
l
T
2
T
3
0
1
2
3
- 14 -
( -1).
.
,
lk,
lk
l
lk
T
(2.9)
,
l
l,
lk,
k
lk,
}
1
.
L
l
K
k
lk
0 0
2
,
1
CM1
CM2
CM3
CM4
- t
(ns
-1
)
0.0233
0.4
0.0667
0.0667
- t(ns
-1
)
2.5
0.5
2.1
2.1
- h
7.1
(dB)
3.4
3.4
3.4
3.4
x
-
X
i
(dB)
3
3
3
3
0
-
/
IFFT.
N
FFT
= 128
. n
l
lN
FFT
n < (l + 1)N
FFT
l N
packet
1,
N
packet
.
,
(Cyclic Prefix CP)
.
.
N
ZP
= 37
0, S (zero padding surfix)
(2.8b). Tuy nhiên, khi
S
+ N
ZP
. i S :
()
()
0
l ZP
l
x n N
xn
(2.11), :
1
2 ( )
0
1
()
()
sau khi
S.
(a) T
S.
N
FFT
ZPS
N
ZP
lN
SYM
lN
SYM
+ N
FFT
(l - 1)N
SYM
lN
SYM
+N
FFT
+N
ZP
=(l+1)N
SYM
lN
FFT
n < lN
SYM
+ N
FFT
,
lN
SYM
+ N
FFT
n < (l + 1)N
SYM,
lN
SYM
n < lN
SYM
+ N
FFT
,
lN
FFT
SYM ZP
FFT
k
N
j n lN N
N
ll
k
FFT
x n X k e
N
,
lN
SYM
n < lN
SYM
+ N
FFT
(2.13) 2.9.
[10]. 1
2 ( )
0
1
()
()
= k/T
FFT
k
.
T
FFT
= 1/D
f
= N
FFT
/f
s
.
f
s
D
f
.
T
ZP
= N
ZP
/f
s
,
2 ( )
c b c
fb
con
b.
(m)
m, q(l)
l
, x
l
(t)
l
3.1).
DAC
DAC
Re{x
l
(n)}
Re{x
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