Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
TURBO CODES IN UMTS/ WIMAX/
LTE SYSTEMS: SOLUTIONS FOR AN
EFFICIENT FPGA IMPLEMENTATION
Ph. D. Cristian ANGHEL
INTRODUCTION
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
Physical Layer - PHY
Radio Link Control - RLC
Media Access Control - MAC
Radio Resource Control - RRC
Non-Access Stratum - NAS
Telecom Protocol Stack
INTRODUCTION
� Forward Error Coding – FEC
� Source coding
� Channel coding
� Block codes (Hamming, Hadamard, cyclic)
� Convolutional codes
� Non-systematic convolutional codes NSC
� Recursive systematic covolutional codes RSC
� Turbo codes
� Systematic codes used in a pseudo-random manner
� All codes are good, except the ones we can think of
(Jacob Wolfowitz)
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
TURBO CODES
� Turbo coding principle
� Coding rate
� [1] C. Berrou, A. Glavieux, and P. Thitimajshima, Near Shannon limit error-correcting coding and decoding: Turbo Codes, IEEE Proceedings of the Int. Conf. on Communications, Geneva, Switzerland, May 1993, pp. 1064-1070.
� [2] C. Berrou and A. Glavieux, Near optimum error correcting coding and decoding: Turbo-Codes, IEEE Trans. Communications, vol. 44, no. 10, pp. 1261-1271, Oct. 1996.
� [3] C. Berrou and M. Jézéquel, Non binary convolutional codes for turbo coding, Electronics Letters, vol. 35, no. 1, pp. 9-40, Jan. 1999.
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
1
3c
R =
TURBO CODES
� UMTS/ WiMAX/ LTE RSC turbo encoder
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
TURBO CODES
� UMTS/ WiMAX/ LTE RSC trellis
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
0
1
2
3
4
5
6
7
k k+1 k+2
00/00
11/00
10/11
01/11
10/11
01/11
00/00
11/00
00/10
11/10
10/01
01/01
10/01
01/01
00/10
11/10
01/00
10/00
11/11
00/11
11/11
00/11
01/00
10/00
01/10
10/10
11/01
00/01
11/01
00/01
01/10
10/10
00/00
11/00
10/11
01/11
10/11
01/11
00/00
11/00
00/10
11/10
10/01
01/01
10/01
01/01
00/10
11/10
01/00
10/00
11/11
00/11
11/11
00/11
01/00
10/00
01/10
10/10
11/01
00/01
11/01
00/01
01/10
10/10
TURBO DECODER
� UMTS/ LTE RSC turbo decoder
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
( )'2
o
kXΛ ( )2
o
kXΛ
( )1
o
kXΛ
( )i
kXΛ
( )i
kZΛ
( )'i
kZΛ
TURBO DECODER
� WiMAX RSC turbo decoder
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
( )01,
i
k kA BΛ
( )10,
i
k kA BΛ
( )11,
i
k kA BΛ
( ),1kWΛ
( ),1kYΛ
( ),2kYΛ
( ),2kWΛ
( )01,
o
k kA BΛ
( )10,
o
k kA BΛ
( )11,
o
k kA BΛ
( )' '
11,
o
k kA BΛ
( )' '
10,
o
k kA BΛ
( )' '
01,
o
k kA BΛ ( )kAΛ
( )kBΛ
TURBO DECODER
� Decoding algorithm
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
max*( , ) ln(e e )
max( , ) ln(1 e ) max( , ).
x y
y x
x y
x y x y− −
= + =
+ + ≈
TURBO DECODER
� Max-Log MAP – WiMAX
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
( )( )( )
,, log
,0, 0
P A a B bk k
A Ba b k k
P A Bk k
= =
Λ =
= =
( ) ( ) ( ) ( )1 ,,
i j i
k k k a b k k k kS S A B w W y Yγ+
→ = Λ + Λ + Λ
( ) ( ) ( ){ }1
'
1 1 1 1max
jik k
j i i j
k k k k k k kS S
S S S Sα α γ+
+ + + +
→
= + →
( ) ( ) ( )' ' 0
1 1 1 1 1 1
j j
k k k k k kS S Sα α α+ + + + + +
= −
( ) ( ) ( ){ }1
'
1 1 1 1max
jik k
i j i j
k k k k k k kS S
S S S Sββ γ+
+ + + +
→
= + →
( ) ( ) ( ) ( )1 1 1 1 1
i j i i j j
k k k k k k k k k kZ S S S S S Sα γ β+ + + + +
→ = + → +
( )( )
{ }1: ,
, maxji
k k
k kS S a b
t a b Z+→
=
( ) ( ) ( ),
, , 0,0o
a b k k k kA B t a b tΛ = −
( ) ( ) ( ){ }
( ) ( ){ }
1,0 1,1
0,0 0,1
max , , ,
max , , ,
o o
k k k k k
o o
k k k k
A A B A B
A B A B
Λ = Λ Λ −
Λ Λ
( ) ( ) ( ){ }
( ) ( ){ }
0,1 1,1
0,0 1,0
max , , ,
max , , ,
o o
k k k k k
o o
k k k k
B A B A B
A B A B
Λ = Λ Λ −
Λ Λ
TURBO DECODER
� Max-Log MAP – WiMAX
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
( )
( ) ( )
( ) ( )
( ) ( )
0 0
1
0 3 0
1 11
0 4 0
1 10
0 7 0
1 01
0
,
, ( ) ( )
, ( ) ( )
k k k
k k k k k
k k k k k k k
k k k k k k k
S S
S S A B
S S A B Y W
S S A B Y W
γ
γ
γ
γ
+
+
+
+
→ =
→ = Λ
→ = Λ + Λ + Λ
→ = Λ + Λ + Λ
( ) ( )
( ) ( )
( )
( ) ( )
1 0 0
1 10
1 3 0
1 01
1 4
1
1 7 0
1 11
, ( ) ( )
, ( ) ( )
0
,
k k k k k k k
k k k k k k k
k k k
k k k k k
S S A B Y W
S S A B Y W
S S
S S A B
γ
γ
γ
γ
+
+
+
+
→ = Λ + Λ + Λ
→ = Λ + Λ + Λ
→ =
→ = Λ
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
' 0 0 0 0
1 1 1 1
' 0 3 0 3
1 1 1 1
' 0 4 0 4
1 1 1 1
' 0 7 0 7
1 1 1 1
a
k k k k k k k
b
k k k k k k k
c
k k k k k k k
d
k k k k k k k
S S S S
S S S S
S S S S
S S S S
β
β
β
β
β γ
β γ
β γ
β γ
+ + + +
+ + + +
+ + + +
+ + + +
= + →
= + →
= + →
= + →
( ) ( ) ( ) ( ) ( ){ }' 0 ' 0 ' 0 ' 0 ' 0max , , ,
a b c d
k k k k k k k k k kS S S S Sβ β β β β=
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
' 0 0 0 0
1 1 1
' 0 1 1 0
1 1 1
' 0 6 6 0
1 1 1
' 0 7 7 0
1 1 1
a
k k k k k k k
b
k k k k k k k
c
k k k k k k k
d
k k k k k k k
S S S S
S S S S
S S S S
S S S S
α α γ
α α γ
α α γ
α α γ
+ + +
+ + +
+ + +
+ + +
= + →
= + →
= + →
= + →
( ) ( ) ( ) ( ) ( ){ }' 0 ' 0 ' 0 ' 0 ' 0
1 1 1 1 1 1 1 1 1 1max , , ,
a b c d
k k k k k k k k k kS S S S Sα α α α α
+ + + + + + + + + +=
TURBO DECODER
� Max-Log MAP – WiMAX
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
( ) ( ) ( ) ( )
( ) ( ) ( ) ( )
( ) ( ) ( ) ( )
( ) ( ) ( ) ( )
( ) ( ) ( )
0 0 0 0 0 0
1 1 1 1 1
1 4 1 1 4 4
1 1 1 1 1
2 1 2 2 1 1
1 1 1 1 1
3 5 3 3 5 5
1 1 1 1 1
4 6 4 4 6
1 1 1
k
k
k
k
k
a
k k k k k k k k k
b
k k k k k k k k k
c
k k k k k k k k k
d
k k k k k k k k k
e
k k k k k k k
Z S S S S S S
Z S S S S S S
Z S S S S S S
Z S S S S S S
Z S S S S S
α γ β
α γ β
α γ β
α γ β
α γ
+ + + + +
+ + + + +
+ + + + +
+ + + + +
+ + +
→ = + → +
→ = + → +
→ = + → +
→ = + → +
→ = + → ( )
( ) ( ) ( ) ( )
( ) ( ) ( ) ( )
( ) ( ) ( ) ( )
6
1 1
5 2 5 5 2 2
1 1 1 1 1
6 7 6 6 7 7
1 1 1 1 1
7 3 7 7 3 3
1 1 1 1 1
k
k
k
k k
f
k k k k k k k k k
g
k k k k k k k k k
h
k k k k k k k k k
S
Z S S S S S S
Z S S S S S S
Z S S S S S S
β
α γ β
α γ β
α γ β
+ +
+ + + + +
+ + + + +
+ + + + +
+
→ = + → +
→ = + → +
→ = + → +
( )( ) ( ) ( ) ( )
( ) ( ) ( ) ( )
0 0 1 4 2 1 3 5
1 1 1 1
4 6 5 2 6 7 7 3
1 1 1 1
, , , ,0,0 max
, , ,
k k k k
k k k k
a b c d
k k k k k k k k
ke f g h
k k k k k k k k
Z S S Z S S Z S S Z S S
t
Z S S Z S S Z S S Z S S
+ + + +
+ + + +
→ → → → =
→ → → →
TURBO DECODER
� Max-Log MAP – LTE
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
( ) ( ) ( ) ( )V , , ,i
ij k kX X i j Z Z i jγ = +Λ
( )( ) ( ) ( )
( ) ( ) ( ){ }
( )( )
( )
1
'
2 1
'
V W ,forSISO1V
V IL W ,forSISO2
, forSISO1
, forSISO2
i
k k k
k o
k k k
i
ki
k i
k
X X X
XX X X
Z
ZZ
= Λ +=
= Λ −
ΛΛ =
Λ
( )
( )
( ) ( )
0
1
2
3
0
V
V
k
i
k
i
k k
X
Z
X Z
γ
γ
γ
γ
=
=
= Λ
= + Λ
00 0 04 3
10 3 14 0
21 1 25 2
31 2 35 1
42 2 46 1
52 1 56 2
63 3 67 0
73 0 77 3
;
;
;
;
;
;
;
;
γ γ γ γ
γ γ γ γ
γ γ γ γ
γ γ γ γ
γ γ γ γ
γ γ γ γ
γ γ γ γ
γ γ γ γ
= =
= =
= =
= =
= =
= =
= =
= =
( ) ( ) ( ){ }
( ) ( ) ( ){ }
( ) ( ) ( ){ }
( ) ( ) ( ){ }
( ) ( ) ( ){ }
( ) ( ) ( )
0 00 4 04
0 10 4 14
1 21 5 25
1 31 5 3
0 1 1
1 1 1
2 1 1
3 1 1
4 1
5
2 42 6 46
2
1
5 1 152 6
ˆ max ( ), ( )
ˆ max ( ), ( )
ˆ max ( ), ( )
ˆ max ( ), ( )
ˆ max ( ), ( )
ˆ max ( ), (
k k k
k k k
k k k
k k k
k k k
k k k
S S S
S S S
S S S
S S S
S S S
S S S
β β γ β γ
β β γ β γ
β β γ β γ
β β γ β γ
β β γ β γ
β β γ β
+ +
+ +
+ +
+ +
+ +
+ +
= + +
= + +
= + +
= + +
= + +
= + +{ }
( ) ( ) ( ){ }
( ) ( ) ( ){ }
56
3 63 7 676 1
3 73 7
1
7 1 771
)
ˆ max ( ), ( )
ˆ max ( ), ( )
k k k
k k k
S S S
S S S
γ
β β γ β γ
β β γ β γ
+ +
+ +
= + +
= + +
( ) ( ) ( ){ }
( ) ( ) ( ){ }
( ) ( ) ( ){ }
( ) ( ) ( ){ }
( ) ( ) ( ){ }
( ) ( ) ( )
0 00 1 10
2 21 3 31
4 42 5 52
6 63 7 7
0 1 1
1 1 1
2 1 1
3 1 1
4 1
3
0 04 1 14
2
1
5 1 125 3
ˆ max ( ),( )
ˆ max ( ), ( )
ˆ max ( ), ( )
ˆ max ( ),( )
ˆ max ( ), ( )
ˆ max ( ), (
k k k
k k k
k k k
k k k
k k k
k k k
S S S
S S S
S S S
S S S
S S S
S S S
α α γ α γ
α α γ α γ
α α γ α γ
α α γ α γ
α α γ α γ
α α γ α
− −
− −
− −
− −
− −
− −
= + +
= + +
= + +
= + +
= + +
= + +{ }
( ) ( ) ( ){ }
( ) ( ) ( ){ }
35
4 46 5 566 1
6 67 7
1
7 1 771
)
ˆ max ( ), ( )
ˆ max ( ), ( )
k k k
k k k
S S S
S S S
γ
α α γ α γ
α α γ α γ
− −
− −
= + +
= + +
TURBO DECODER
� Max-Log MAP – LTE
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
0 00 0
1 14 4
2 25 5
3 31 1
4 42 2
5 56 6
6 67
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
7
7 73 3
0,0
1,4
2,5
3,1
4,2
5,6
6,7
7,3
k
k
k
k
k
k
k
k
k k
k k
k k
k k
k k
k k
k k
k k
S S
S S
S S
S S
S S
S S
S S
S S
λ α γ β
λ α γ β
λ α γ β
λ α γ β
λ α γ β
λ α γ β
λ α γ β
λ α γ β
−
−
−
−
−
−
−
−
+
+
+
+
+
= +
= +
= +
= +
= +
=
= +
+ +
+
=
+
+
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
0 04 4
1 10 0
2 21 1
3 35 5
4 46 6
5 52 2
6 63
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
7 77 7
0,4
1,0
2,1
3,5
4,6
5,2
6,3
7,7
k
k
k
k
k
k
k
k
k k
k k
k k
k k
k k
k k
k k
k k
S S
S S
S S
S S
S S
S S
S S
S S
λ α γ β
λ α γ β
λ α γ β
λ α γ β
λ α γ β
λ α γ β
λ α γ β
λ α γ β
−
−
−
−
−
−
−
−
+
+
+
+
+
= +
= +
= +
= +
= +
=
= +
+ +
+
=
+
+
( ) ( ) ( )1 0
( ): 1 ( ): 0max { , } max { , },
i j i i j i
o
k k kS S X S S X
X i j i jλ λ→ = → =
Λ = −
TURBO DECODER
� LTE - Quadratic Permutation Polynomial (QPP)
interleaver
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
Kififi mod)()( 2
21⋅+⋅=π
( )0 1 1 2
0 0 2
1 1 2
2 2 1 0 2
2
sum (0) ,sum (0) 0,sum (0) 0
0 0
1: 1
sum ( ) sum ( 1)
sum ( ) sum ( 1)
sum ( ) sum ( 1) sum ( 1) sum ( 1)
( ) sum ( ) mod
f
for i K
i i f
i i f
i i i i f
i i K
end
π
π
= = =
=
= −
= − +
= − +
= − + − + − +
=
TURBO DECODER
� LTE - Quadratic Permutation Polynomial (QPP)
interleaver
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
SISO
MEM
39, 38, 37,�, 5,4,3,2,1,0
TURBO DECODER
� LTE - Quadratic Permutation Polynomial (QPP)
interleaver
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
SISO
MEM
7,34,1,28,...,12,19,6,13,0
TURBO DECODER
� LTE - Quadratic Permutation Polynomial (QPP)
interleaver
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
0
1
2
3
4
SISO0
MEM0
4,3,2,1,0
5
6
7
8
9
SISO1
MEM1
9,8,7,6,5
10
11
12
13
14
SISO2
MEM2
14,13,12,11,10
15
16
17
18
19
SISO3
MEM3
19,18,17,16,15
20
21
22
23
24
SISO4
MEM4
24,23,22,21,20
25
26
27
28
29
SISO5
MEM5
29,28,27,26,25
30
31
32
33
34
SISO6
MEM6
34,33,32,31,30
35
36
37
38
39
SISO7
MEM7
39,38,37,36,35
TURBO DECODER
� LTE - Quadratic Permutation Polynomial (QPP)
interleaver
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
0
1
2
3
4
SISO0
MEM0
12,19,6,13,0
5
6
7
8
9
SISO1
MEM1
37,24,31,18,25
10
11
12
13
14
SISO2
MEM2
2,9,36,3,30
15
16
17
18
19
SISO3
MEM3
7,14,21,8,15
20
21
22
23
24
SISO4
MEM4
32,39,26,33,20
25
26
27
28
29
SISO5
MEM5
17,4,11,38,5
30
31
32
33
34
SISO6
MEM6
22,29,16,23,10
35
36
37
38
39
SISO7
MEM7
7,34,1,28,35
0
1
2
3
4
SISO0
MEM0
12,19,6,13,0
5
6
7
8
9
SISO1
MEM1
37,24,31,18,25
10
11
12
13
14
SISO2
MEM2
2,9,36,3,30
15
16
17
18
19
SISO3
MEM3
7,14,21,8,15
20
21
22
23
24
SISO4
MEM4
32,39,26,33,20
25
26
27
28
29
SISO5
MEM5
17,4,11,38,5
30
31
32
33
34
SISO6
MEM6
22,29,16,23,10
35
36
37
38
39
SISO7
MEM7
7,34,1,28,35
0
1
2
3
4
SISO0
MEM0
12,19,6,13,0
5
6
7
8
9
SISO1
MEM1
37,24,31,18,25
10
11
12
13
14
SISO2
MEM2
2,9,36,3,30
15
16
17
18
19
SISO3
MEM3
7,14,21,8,15
20
21
22
23
24
SISO4
MEM4
32,39,26,33,20
25
26
27
28
29
SISO5
MEM5
17,4,11,38,5
30
31
32
33
34
SISO6
MEM6
22,29,16,23,10
35
36
37
38
39
SISO7
MEM7
7,34,1,28,35
TURBO DECODER
� LTE - Quadratic Permutation Polynomial (QPP)
interleaver
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
K/N
locations
N positions per
location
Index i = 0 : K-1
WA = mod(i, K/N)
WP = floor(i, K/N)
RA = WA + 1
PC=IL(i)
WA = write address
RA = read address
WP = write position
PC = position content
IL = interleaver
...
TURBO DECODER
� LTE – reordering unit: even-odd merge sorting
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
TURBO DECODER
� LTE – split with overlap
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
TURBO DECODER
� WiMAX – proposed architecture
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
AG
MEM
IN
MEM
AUX
MEM
IN2
MEM
W
MEM
PARIL
M
U
X
1
D
M
U
X
1
M
U
X
2D
M
U
X
2
+
+
+
DLY+
+
+
+ + +
+
+
+
- - -
--
-
+ + +
SISO
CONTROL
1Tclk 1Tclk
6Tclk
LLR
2
BYTE
Read addressWrite addressWrite enable
Start trellisData ValidDelay value
SISO1/2Switch in.buff
Mux1 SelMux2 Sel
( )10 ,
i
k kA BΛ
( )01 ,
i
k kA BΛ
( )11 ,
i
k kA BΛ
( ),k jYΛ
( ),k jWΛ
TURBO DECODER
� LTE – proposed architecture
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
( )i
kXΛ
( )i
kZΛ
( )'i
kZΛ
( )1
o
kXΛ
( )'2
o
kXΛ
( )2
o
kXΛ ˆ
kX
2
o
Λ
2
o
Λ
TURBO DECODER
� LTE – SISO proposed architecture
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
( )
( )1
'
2
V /
V
k
k
X
X
( )
( )'/
i
k
i
k
Z
Z
Λ
Λ
( )
( )1
'
2
/o
k
o
k
X
X
Λ
Λ
TURBO DECODER
� LTE – timing diagram: serial vs. parallel
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
Λi(Xk)
memory
Λi(Zk)
memory
Λi(Z’k)
memory
W(Xk)
memory
V2(Xk)
memory
GAMMA
ALPHA
BETA
MEM_BETA
L
SISO
MO
DU
LE
S f
rom
AR
CH
ITE
CT
UR
E
SISO1 SISO2
R(K-1:0) R(0:K-1)
R(K-1:0) R(0:K-1)
COMPUTE COMPUTE
COMPUTE
COMPUTE
COMPUTE
COMPUTE COMPUTE
COMPUTE
COMPUTE
COMPUTE
W(0:K-1)
RESET/W(K-1:0) RESET/R(0:K-1)
W(K-1:0) R(0:K-1)
R{IL(K-1:0)} R{IL(0:K-1)}
W(K-1:0) R(0:K-1)
Λ2
o(X’k)
memory
R(K-1:0) R(0:K-1)
W{IL(0:K-1)}
TIME
(clock periods)
0 2K+Delay 3K+Delay 4K+2*DelayK
R(K-1:0)
R(K-1:0)
IL
memoryR(K-1:0) R(0:K-1)
TURBO DECODER
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
Λi(Xk)
memory
Λi(Zk)
memory
Λi(Z’k)
memory
W(Xk)
memory
V2(Xk)
memory
GAMMA
ALPHA
BETA
MEM_BETA
L
SISO
a
MO
DU
LE
S fro
m A
RC
HIT
EC
TU
RE
SISO1SISO2
R(K/2-1:0) R(0:K/2-1)
R(K/2-1:0) R(0:K/2-1)
COMPUTE COMPUTE
COMPUTE
COMPUTE
COMPUTE
COMPUTE COMPUTE
COMPUTE
COMPUTE
COMPUTE
W(0:K/2-1)
RESET/W(K/2-1:0) RESET/R(0:K/2-1)
W(K/2-1:0) R(0:K/2-1)
R{IL(K/2-1:0)} R{IL(0:K/2-1)}
W(K/2-1:0) R(0:K/2-1)
Λ2
o(X’k)
memory
R(K/2-1:0) R(0:K/2-1)
W{IL(0:K/2-1)}
GAMMA
ALPHA
BETA
MEM_BETA
L
SISO
b
TIME
(clock periods)
0 K+Delay 3K/2+Delay 2K+2*DelayK/2
COMPUTE COMPUTE
COMPUTE
COMPUTE
COMPUTE
COMPUTE COMPUTE
COMPUTE
COMPUTE
COMPUTE
W(K/2-1:0) R(0:K/2-1) W(K/2-1:0) R(0:K/2-1)
R(K/2-1:0)
R(K/2-1:0)
IL
memoryR(K/2-1:0) R(0:K/2-1)
OBTAINED RESULTS
� WiMAX
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
Number of Iterations Block Size
L=48, QPSK 1/2 K=1, QPSK 1/2
1 1.5 2 2.5 3 3.5 4 4.5 510
-6
10-5
10-4
10-3
10-2
10-1
100
RSZ[dB]
REB
K= 1
K= 2
K= 3
K= 4
BER
SNR[dB]
1 1.5 2 2.5 3 3.5 4 4.5 510
-7
10-6
10-5
10-4
10-3
10-2
10-1
100
RSZ[dB]
REB
L= 24
L= 48
L= 240
BER
SNR[dB]
OBTAINED RESULTS
� WiMAX
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
Number of Retransmisions
L=24, QPSK ½, K=4
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 310
-5
10-4
10-3
10-2
10-1
100
RSZ[dB]
REP
transmisie
1 retransmisie
2 retransmisii
3 retransmisii
4 retransmisii
PER
SNR[dB]
transmission
1 retransmission
2 retransmission
3 retransmission
4 retransmission
OBTAINED RESULTS
� LTE
Number of Iterations Block Size
L=512, QPSK 1/2 K=3, QPSK 1/2
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
-6 -5 -4 -3 -2 -1 0 1 210
-6
10-5
10-4
10-3
10-2
10-1
100
SNR [dB]
BER
K=40
K=512
K=6144
-6 -5 -4 -3 -2 -1 0 1 2 310
-5
10-4
10-3
10-2
10-1
100
SNR [dB]
BER
iter=1
iter=2
iter=3
iter=4
iter=5
OBTAINED RESULTS
� LTE
Parallel N=2 Parallel N=4
L=512, QPSK 1/2, K=3 L=1024, QPSK 1/2, K=3
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
-3 -2 -1 0 1 2 310
-5
10-4
10-3
10-2
10-1
100
QPSK, 3 iter, 512 bits, N = 2
SNR[dB]
BER
serial
parallel with overlap
parallel without overlap
-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.510
-5
10-4
10-3
10-2
10-1
100
QPSK, 1024, 3 iter, N = 4
SNR[dB]
BER
parallel with overlap
parallel without overlap
serial
CONCLUSIONS
� Efficient Max-Log MAP implementation
� Only one SISO
� All latency-reduction procedures can be applied
over the proposed decoding scheme
� Turbo decoding serial architecture adapted for
parallel decoding
� Only one interleaver used in the proposed parallel
decoding architecture
� Efficient implementation for the interleaver
� Almost identical decoding performances for serial
vs. parallel decoding when small overlap accepted
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
IARIA - The Eleventh Advanced International Conference on Telecommunications AICT 2015
THANK YOU