About the T-DMB/DAB Option
R&S
®
SMCVB-K156
16
User Manual 1179.1029.02 ─ 02
for audio services, equal error protection (EEP) for audio and data services. The sam-
pling frequency is respectively 48
kHz and 24
kHz.
The convolutional coder is a punctured convolution code, based on a mother convolu-
tional code with constraint length 7 and rate 1/4.
The generator polynomials are G
1
=(1,0,1,1,0,1,1), G
2
=(1,1,1,1,0,0,1),
G
3
=(1,1,0,0,1,0,1) and G
4
=(1,0,1,1,0,1,1).
To avoid the need for additional signaling overhead, the data in the FIC are encoded
with fixed, equal channel coding, with a constant 1/3 coding rate.
The puncturing procedures applied for the coding in the MSC is a combination of pro-
tection profile and protection level. There are number of permissible protection profiles
defined for each of the allowed bit rates. Each protection profile is associated with a
protection level. Protection level 1 is the highest level within the same profile.
Error protec-
tion
Protection Profile
Bit rate
Protection Level
Code Rate
UEP
four different pro-
tection profiles
14 different bit rates
1, 2, 3, 4, 5
0,34..0,75
(64 different data
rates - protection
level combinations)
EEP
A
Multiples of 8
kbit/s
1-A
1/4
2-A
3/8
3-A
1/2
4-A
3/4
B
Multiples of 32
kbit/s
1-B
4/9
2-B
4/7
3-B
2/3
4-B
4/5
3.2.6
Time Interleaving
Time interleaving is applied prior to block generation at the output of each convolu-
tional encode contributing to the sub-channels in the MSC. It is not applied to the FIC.
The time interleaving process covers 16
CIFs, 24
ms each. This results in an overall
processing delay of 384
ms.
About DAB/T-DMB
