Ed MrTz
Posts:
3
Registered:
8/22/12
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Re: commBCHEncoder/commBCHDecoder
Posted:
Aug 25, 2012 5:18 AM
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Thanks so much, Ethem Sozer!!!!
It has been really useful!!!! Now, I can continue with the other blocks!
Thanks also to Bahman for the interest. I told that I was trying without channel block (awgn) and modulation.
Regards
Ethem Sozer" <esozer@mathworks.com> wrote in message <k12mok$784$1@newscl01ah.mathworks.com>...
> The input of decode method should be a bipolar soft signal where a 0 is
> represented by a real number greater than zero, and a 1 is represented by a
> real number less than 0. If you try:
>
> >> decodedmsg = decode(dec, 1-2*codeword);
>
> You should see zero errors. A more realistic simulation would be
>
> rcvd = awgn(1-2*codeword, SNR); % chose an SNR value
> decodedmsg = decode(dec, rcvd);
>
> Hth,
> Ethem
>
>
> "Bahman " <bahmanazarbad@yahoo.com> wrote in message
> news:k12hvh$ihk$1@newscl01ah.mathworks.com...
> > "Ed MrTz" wrote in message <k12c08$sbt$1@newscl01ah.mathworks.com>...
> >> "Bahman " <bahmanazarbad@yahoo.com> wrote in message
> >> <k0hsbu$1kd$1@newscl01ah.mathworks.com>...
> >> > "Fulus " <case28@gmail.com> wrote in message
> >> > <k0g2j4$ar5$1@newscl01ah.mathworks.com>...
> >> > > > Hi dear
> >> > > >
> >> > > > is your bbframe a row vector?
> >> > > > because error indicates that it is a column vector,try it inverted
> >> > > > (BBframe')
> >> > >
> >> > > Hello, yeah you right, I nverted it and it runs without errors now
> >> > > however, it still isnt function as it suppose to because as I go
> >> > > higher in Eb/No my BER isnt going lower but is actually increasing by
> >> > > a tiny amount. That is the Decoder is still introducing errors.
> >> >
> >> > Hi dear
> >> > you need to be careful about the noise you are introducing to awgn as
> >> > well as noise variance you need to set in demodulator
> >>
> >> Hi Everyone!
> >>
> >> I hope that someone could help me, even.
> >>
> >> I had the sames problems with BCH and LDPC Enc/Dec to make it
> >> run......but at the end I can solved.
> >>
> >> Now, my problem is that when I use (without add a AWGN channel and
> >> modulation) encoder and decoder of BCH (in raw)......its returns 0 errors
> >> between the original msg and received/decoded msg. But its not so when I
> >> use LDPC (in raw) because I get to many errors (original msg - decoded
> >> msg).
> >>
> >> Do you know why? I attach the code that I use:
> >> H=dvbs2ldpc(1/4);
> >> enc = fec.ldpcenc(H); dec = fec.ldpcdec(H);
> >> dec.DecisionType = 'Hard decision';
> >> dec.OutputFormat = 'Information part';
> >> dec.NumIterations = 50;
> >>
> >> msg = randi([0 1],1,enc.NumInfoBits);
> >> codeword = encode(enc,msg);
> >>
> >> decodedmsg = decode(dec, codeword);
> >
> >
> >>
> >> % Compare with original message
> >> disp(['Number of bits incorrectly decoded = ' ...
> >> num2str(nnz(decodedmsg-msg))]);
> >>
> >> THANXXXX
> > DEAR WHERE IS YOUR TRANSMISSION CHANNEL??????
> > BAHMAN
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