Ethem
Posts:
9
Registered:
1/26/09
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Re: commBCHEncoder/commBCHDecoder
Posted:
Dec 20, 2010 11:07 AM
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Hi Spiros,
You also need to set the appropriate primitive polynomial. Please have a look at the function called "getParamsDVBS2Demo" that comes with the DVBS2 demo. The demo uses the G^16 minimum weight primitive polynomial (e.g. primpoly(16,'min')).
Hth,
Ethem
"Spiros " <spzettas@gmail.com> wrote in message <ieikf0$s16$1@fred.mathworks.com>...
> Hi to all,
> This question is considered with the use of Communications
> Toolbox/Blockset.
>
> I am trying to write a m-file that uses the comm.BCHEncoder/comm.Decoder in MATLAB R2010b for the DVB-T2 (DVB-S2 are the same) standard?.
>
> In the DVB-S.2 model in Simulink the compiler doesn't complaint for any LDPC rate and everything seems OK.
> In my code,if I try to use comm.BCHEncoder with any code rate other than 1/2 again everything is OK.
> When I try Kbch=32208 and Nbch=32400,
> I get an error:The values for N and K do not produce a valid narrow-sense BCH code.
>
> %-----------------BCH encoding.... --------------------------------------
> %
> % Constrution of BCH_Encoder and BCH_Decoder
> N_BCH=32400;
> K_BCH=32208;
> BBFrame=round(rand(32208,1));
> BCH_Encoder=comm.BCHEncoder('CodewordLength',N_BCH,'MessageLength',K_BCH,'GeneratorPolynomial',g);
> BCH_Decoder=comm.BCHDecoder('CodewordLength',N_BCH,'MessageLength',K_BCH,'GeneratorPolynomial',g);
>
> BCHFrame=step(BCH_Encoder
> Where BBframe is a random 32400 binary vector, and g the generator polynomial exactly the same as in the Simulink model DVB.S2 (can be found under "dvb stuct".
> P.S. I also tried to use the PrimitivePolynomial with no success.
>
> Hope for help
> kindly regards Spiros
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