Hi, I have a problem with interleaving and soft-decision. First, i explain what i have realized. I have done a 16FSK receiver with FEC decoded Viterbi 1/2 and k=7. Then, a symbol are 4 bits and i have 16 tones for 16 symbols: For example: 1001 is the symbol 9 and the tone number 9. 0010 is the symbol 2 and the tone number 2. (Actually, i also use Gray Code, but that's is not important now.) Using the FFT algoritm I can get the energy of each tone, then i have the METRIC for soft-decision decoder. But my big problem is: If i use an interleaver for separate the bits, then i can not recover the metric of original symbol, because thats metric depend of four differents symbols. I explain better: Bits original: A C E G I J ....etc... Bits coded: "ABCD EFGH IJKL MOPQ RSTU VWXY Z012 3456....." Symbols coded(or tones): 4 5 0 12 9 15 13 4 ... Diagonal interleaver: AEIMQUY... BFJNRVZ... CGKOSW0... DHLPTX1... Bits interleaving: AFKP EJOT INSX MRW1 ... Symbols(or tones) to send: 5 11 13 7 .... for example --------TO THE ANTENNA--------- In the receiver i can get metric of symbols: "5", "11", "13", etc...., but what i need is the metric for symbols "4", "5", "0" etc.... because thats symbols are just the coded symbols. ¿Any idea?

# Interleaving with soft-decision

Started by ●August 30, 2009

Posted by ●August 30, 2009

JAlbertoDJ <nietorosdj@yahoo.es> wrote:>Hi, > >Using the FFT algoritm I can get the energy of each tone, then i have the >METRIC for soft-decision decoder.Why would one use an FFT here?>But my big problem is: If i use an interleaver for separate the bits, then >i can not recover the metric of original symbol, because thats metric >depend of four differents symbols.It is unfortunate that searching groups.google.com is not fuctional, because I answered a very similar question here several months ago in some detail. You need to compute the a-priori probability for each received bit. Steve

Posted by ●August 30, 2009

JAlbertoDJ wrote:> Hi, > > I have a problem with interleaving and soft-decision. First, i explain > what i have realized. > I have done a 16FSK receiver with FEC decoded Viterbi 1/2 and k=7. > Then, a symbol are 4 bits and i have 16 tones for 16 symbols:This has "homework" written over it. Just to add to what Steve Pope noted, your channel coding is very unoptimal. Consider convolutional base 4 code. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com

Posted by ●August 31, 2009

>Why would one use an FFT here?Because it is more quickly of correlation for 16 tones. Also, tones are continuous phase, then with one sample for each tone i have information of all his energy.> >It is unfortunate that searching groups.google.com is not fuctional, >because I answered a very similar question here several months >ago in some detail. You need to compute the a-priori probability for >each received bit. > > >Steve >Could you tell me the link to thats information? thenk you

Posted by ●August 31, 2009

> > >Just to add to what Steve Pope noted, your channel coding is very >unoptimal. Consider convolutional base 4 code. > >base 4??? i dont understand. Could you explain better?

Posted by ●August 31, 2009

JAlbertoDJ wrote:>> >>Just to add to what Steve Pope noted, your channel coding is very >>unoptimal. Consider convolutional base 4 code. > > base 4??? i dont understand. Could you explain better?Dual-K codes. Proakis 8.2.6. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com

Posted by ●August 31, 2009

> > >JAlbertoDJ wrote: > >>> >>>Just to add to what Steve Pope noted, your channel coding is very >>>unoptimal. Consider convolutional base 4 code. >> >> base 4??? i dont understand. Could you explain better? > >Dual-K codes. >Proakis 8.2.6. > > >Vladimir Vassilevsky >DSP and Mixed Signal Design Consultant >http://www.abvolt.com > >Unfortunally, i have not that book and i dont find information about Dual-K codes. But i am reading something about TURBO-CODES and Tutbo-Codes have an interleaver inside. Then, could be it the solution? Are turbo-codes efficients for 16CPFSK?

Posted by ●August 31, 2009

JAlbertoDJ wrote:>> >>JAlbertoDJ wrote: >> >> >>>>Just to add to what Steve Pope noted, your channel coding is very >>>>unoptimal. Consider convolutional base 4 code. >>> >>>base 4??? i dont understand. Could you explain better? >> >>Dual-K codes. >>Proakis 8.2.6. >> > > Unfortunally, i have not that book and i dont find information about > Dual-K codes. > > But i am reading something about TURBO-CODES and Tutbo-Codes have an > interleaver inside. > > Then, could be it the solution? Are turbo-codes efficients for 16CPFSK?The chasm of your ignorance is really bottomless. If you don't have The Book Of Proakis, then you should go and get it. And don't ask any questions before you read The Book from the first to the last page. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com

Posted by ●September 1, 2009

> > >JAlbertoDJ wrote: > >>> >>>JAlbertoDJ wrote: >>> >>> >>>>>Just to add to what Steve Pope noted, your channel coding is very >>>>>unoptimal. Consider convolutional base 4 code. >>>> >>>>base 4??? i dont understand. Could you explain better? >>> >>>Dual-K codes. >>>Proakis 8.2.6. >>> >> >> Unfortunally, i have not that book and i dont find information about >> Dual-K codes. >> >> But i am reading something about TURBO-CODES and Tutbo-Codes have an >> interleaver inside. >> >> Then, could be it the solution? Are turbo-codes efficients for16CPFSK?> >The chasm of your ignorance is really bottomless. > >If you don't have The Book Of Proakis, then you should go and get it. >And don't ask any questions before you read The Book from the first to >the last page. > > >Vladimir Vassilevsky >DSP and Mixed Signal Design Consultant >http://www.abvolt.com > > >Thank you very much

Posted by ●September 1, 2009

Vladimir Vassilevsky <nospam@nowhere.com> wrote in news:MfqdnYYF2sD- ygHXnZ2dnUVZ_g-dnZ2d@giganews.com:> > The chasm of your ignorance is really bottomless. > > If you don't have The Book Of Proakis, then you should go and get it. > And don't ask any questions before you read The Book from the first to > the last page.As a previous victim of your verbal abuse, I don't feel so bad because I now know that you didn't specifically single me out. Given your above comment, there is no longer any doubt whatsoever my mind that arrogance and verbal abuse are the primary, if not the only ingredients that comprise your sad and pathetic MO. The bottomless ignorance, which you assign to the persone who naively came here for help, is only overshadowed by your unbounded arrogance and your uncontrolled abusive tongue. It is beyond me to comprehend why you are here and why you respond in the offensive manner that you do, but then I'm not a psychiatrist.