Having a hard time figuring out how to properly do soft decoding with vitdec for bpsk. I tried using 'unquant' but my results are the same as hard decision decoding. trellis = poly2trellis(4,[11 15]); for i = 1:7 for q = 1:n_block %create coded message code = convenc(msg(:,q),trellis); %convert to bpsk code_bpsk = 2*code-1; %add noise tx = code_bpsk' + sqrt(No(i)/2)*n; %hard decoding rx_hard = tx > 0; decode = vitdec(rx_hard,trellis,5*4,'trunc','hard'); decodesoft = vitdec(rx_hard,t2,5*4, 'trunc', 'soft',3); [num rt] = biterr(decode,msg(:,q)'); [numsoft rt2] = biterr(decodesoft,msg(:,q)'); %soft err_conv_soft(i) = err_conv_soft(i) + numsoft; %hard err_conv(i) = err_conv(i) + num; end err_conv(i) = err_conv(i)/(block_sz*n_block); err_conv_soft(i) = err_conv_soft(i)/(block_sz*n_block); end --------------------------------------- Posted through http://www.DSPRelated.com
Constitutional encoding/ decoding
Started by ●April 25, 2017
Reply by ●April 25, 20172017-04-25
I'm not sure; is decoding a right or a privilege? On Tue, 25 Apr 2017 12:11:42 -0500, "somedspguy" <120759@DSPRelated> wrote:>Having a hard time figuring out how to properly do soft decoding with >vitdec for bpsk. I tried using 'unquant' but my results are the same as >hard decision decoding. > >trellis = poly2trellis(4,[11 15]); >for i = 1:7 > for q = 1:n_block > >%create coded message > code = convenc(msg(:,q),trellis); > >%convert to bpsk > code_bpsk = 2*code-1; > >%add noise > tx = code_bpsk' + sqrt(No(i)/2)*n; > >%hard decoding > rx_hard = tx > 0; > > > decode = vitdec(rx_hard,trellis,5*4,'trunc','hard'); > decodesoft = vitdec(rx_hard,t2,5*4, 'trunc', 'soft',3); > > > > [num rt] = biterr(decode,msg(:,q)'); > [numsoft rt2] = biterr(decodesoft,msg(:,q)'); > > %soft > err_conv_soft(i) = err_conv_soft(i) + numsoft; > > %hard > err_conv(i) = err_conv(i) + num; > > end > err_conv(i) = err_conv(i)/(block_sz*n_block); > err_conv_soft(i) = err_conv_soft(i)/(block_sz*n_block); > >end > > > >--------------------------------------- >Posted through http://www.DSPRelated.com--- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Reply by ●April 26, 20172017-04-26
To Eric: for Octave users it's a right; for Matlab users it's a privilege. To the OP: precisely what is hard decoding and what is soft decoding? In which ways does soft decoding differ from hard? If you are unsure, I suggest you to open a textbook (e.g. by Proakis) and keep reading it until you are able to see what's wrong with your code. Fortunately, even the best tools cannot substitute knowledge. Gene On 26.04.2017 1:06, eric.jacobsen@ieee.org wrote:> I'm not sure; is decoding a right or a privilege? > > > On Tue, 25 Apr 2017 12:11:42 -0500, "somedspguy" <120759@DSPRelated> > wrote: > >> Having a hard time figuring out how to properly do soft decoding with >> vitdec for bpsk. I tried using 'unquant' but my results are the same as >> hard decision decoding. >> >> trellis = poly2trellis(4,[11 15]); >> for i = 1:7 >> for q = 1:n_block >> >> %create coded message >> code = convenc(msg(:,q),trellis); >> >> %convert to bpsk >> code_bpsk = 2*code-1; >> >> %add noise >> tx = code_bpsk' + sqrt(No(i)/2)*n; >> >> %hard decoding >> rx_hard = tx > 0; >> >> >> decode = vitdec(rx_hard,trellis,5*4,'trunc','hard'); >> decodesoft = vitdec(rx_hard,t2,5*4, 'trunc', 'soft',3); >> >> >> >> [num rt] = biterr(decode,msg(:,q)'); >> [numsoft rt2] = biterr(decodesoft,msg(:,q)'); >> >> %soft >> err_conv_soft(i) = err_conv_soft(i) + numsoft; >> >> %hard >> err_conv(i) = err_conv(i) + num; >> >> end >> err_conv(i) = err_conv(i)/(block_sz*n_block); >> err_conv_soft(i) = err_conv_soft(i)/(block_sz*n_block); >> >> end >> >> >> >> --------------------------------------- >> Posted through http://www.DSPRelated.com > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus >
Reply by ●April 26, 20172017-04-26
Evgeny Filatov <filatov.ev@mipt.ru> writes:> [...] > Fortunately, even the best tools cannot substitute knowledge.Yes! A computer is an amplifier for the mind: noise-in, noise-out. --Randy> > Gene > > > On 26.04.2017 1:06, eric.jacobsen@ieee.org wrote: >> I'm not sure; is decoding a right or a privilege? >> >> >> On Tue, 25 Apr 2017 12:11:42 -0500, "somedspguy" <120759@DSPRelated> >> wrote: >> >>> Having a hard time figuring out how to properly do soft decoding with >>> vitdec for bpsk. I tried using 'unquant' but my results are the same as >>> hard decision decoding. >>> >>> trellis = poly2trellis(4,[11 15]); >>> for i = 1:7 >>> for q = 1:n_block >>> >>> %create coded message >>> code = convenc(msg(:,q),trellis); >>> >>> %convert to bpsk >>> code_bpsk = 2*code-1; >>> >>> %add noise >>> tx = code_bpsk' + sqrt(No(i)/2)*n; >>> >>> %hard decoding >>> rx_hard = tx > 0; >>> >>> >>> decode = vitdec(rx_hard,trellis,5*4,'trunc','hard'); >>> decodesoft = vitdec(rx_hard,t2,5*4, 'trunc', 'soft',3); >>> >>> >>> >>> [num rt] = biterr(decode,msg(:,q)'); >>> [numsoft rt2] = biterr(decodesoft,msg(:,q)'); >>> >>> %soft >>> err_conv_soft(i) = err_conv_soft(i) + numsoft; >>> >>> %hard >>> err_conv(i) = err_conv(i) + num; >>> >>> end >>> err_conv(i) = err_conv(i)/(block_sz*n_block); >>> err_conv_soft(i) = err_conv_soft(i)/(block_sz*n_block); >>> >>> end >>> >>> >>> >>> --------------------------------------- >>> Posted through http://www.DSPRelated.com >> >> >> --- >> This email has been checked for viruses by Avast antivirus software. >> https://www.avast.com/antivirus >> >-- Randy Yates, Embedded Firmware Developer Garner Underground, Inc. 866-260-9040, x3901 http://www.garnerundergroundinc.com
