Hi,
The
RS and convolutional coding is added to the MPEG TS as part of the
modulation process within the DVB-RCS compliant satellite modulator. The
additional overhead for convolutional encoding is added, along with the
interleaving and additional RS bits. This is separate from the MPEG-TS and is
purely done on a byte-by-byte (bit-by-bit?!) basis.
This
will be the same with ATM cells - the string of 0's and 1's is encoded with
convolutional and then RS coding. At the receiver, the incoming signal is
demodulated, the RS is removed and de-interleaved, then the convolutional
decoder ideally recovers the same string of bits that went into the
modulator.
It
does not matter to the satellite modems if the incoming string of bits are
part of an MPEG-TS or a series of ATM cells.
The
same is true for turbo codes, although the coding is a single
step.
Hope
this is of some help?
Adrian.
Manager: Satellite System
Engineering
BT Ignite,
B&SC - Satellite System Development
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Hi
everybody,
Something is not
clear for me, with the DVB-RCS standard.
It is possible,
for coding, to use either reed-solomon / convolutionnal coding, either
turbo-codes. But in specifications, it is possible not to use
MPEG-2 TS over DVB-RCS, whereas the (reed-solomon) redundancy is well
defined (trailer of the mpeg-2 TS packet). How can we do, for coding,
if we use for instance ATM cells ? Is some specific headers are defined for
this ? How can we use DVB-RCS without MPEG-2 TS about
that?
With regards,
_______________________________________
Fabrice Arnal - Laboratoire
TéSA
2, rue Charles Camichel
BP 7122 - 31071 Toulouse Cedex 7
France
Tel : 05 61 58 80 15