FPGA Central

Hello all,

I have read a paper by the inventor of DVB-S2. He said the LDPC code
used in DVB-S2 is a irregular RA. But I found the encode method and
decode method adopted in LDPC and RA code is similar. What's their main
intuitive difference? Is it the code construction method? Any ideas
will be appreciated.

Best Regards,
Davy

"Davy" <[email protected]> writes:

> Hello all,
>
> I have read a paper by the inventor of DVB-S2. He said the LDPC code
> used in DVB-S2 is a irregular RA. But I found the encode method and
> decode method adopted in LDPC and RA code is similar. What's their main
> intuitive difference? Is it the code construction method? Any ideas
> will be appreciated.

Perhaps a citation of the paper would be useful? (duh!)
--
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
[email protected], 919-472-1124

The paper is "A Synthesizable IP Core for DVB-S2 LDPC Code Decoding".

It said "The LDPC codes as defined in the DVB-S2 standard are IRA
codes, thus the encoder realization is straight forward."

Regards,
Davy

"Davy" <[email protected]> wrote in message
news:[email protected] oups.com...
> The paper is "A Synthesizable IP Core for DVB-S2 LDPC Code Decoding".
>
> It said "The LDPC codes as defined in the DVB-S2 standard are IRA
> codes, thus the encoder realization is straight forward."
>
> Regards,
> Davy
>
If you can find this :
"DESIGN TECHNIQUES FOR GRAPH-BASED ERROR-CORRECTING CODES

AND THEIR APPLICATIONS"

A Dissertation by CHING FU LAN

I think that the author discusses why the encoder is simpler.

Best of Luck - Mike

On 26 Apr 2005 05:05:07 -0700, "Davy" <[email protected]> wrote:

>The paper is "A Synthesizable IP Core for DVB-S2 LDPC Code Decoding".
>
>It said "The LDPC codes as defined in the DVB-S2 standard are IRA
>codes, thus the encoder realization is straight forward."
>
>Regards,
>Davy

I don't recall the construction of the DVB-S2 code, but if the parity
check portion of the matrix is a dual-diagonal descending staircase
then it can be encoded with a differential encoder (the accumulate
idea). It's been too long since I looked at that code, so I don't
recall whether it has this property or not.

That's the simplest encoding scheme for LDPCs of which I'm aware.



Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org