Forums

Reed Solomon vs Convolutional coding

Started by JAlbertoDJ September 30, 2009
>> >If the target bit error rate is as high as 0.01, you are not going to >gain much by using any reasonable coding. You'd be better by using the >direct uncoded modulation, especially if you account for the modem
losses.
> > >Vladimir Vassilevsky >DSP and Mixed Signal Design Consultant >http://www.abvolt.com > >
0.01 would be the maximum error permissible. Modem should work from 0.01 to below. Apart from this, in the following graphics, at Pb=0.01 gain code for unconcatenated system (7,1/2) is still of 3.5 dBs. ?? http://books.google.es/books?id=yws55Rx1orEC&lpg=PA28&ots=V1tU4L7wbd&dq=voyager%20reed%20solomon&pg=PA27#v=onepage&q=&f=false

JAlbertoDJ wrote:
>>If the target bit error rate is as high as 0.01, you are not going to >>gain much by using any reasonable coding. You'd be better by using the >>direct uncoded modulation, especially if you account for the modem > > losses. > > 0.01 would be the maximum error permissible. Modem should work from 0.01 > to below. > > Apart from this, in the following graphics, at Pb=0.01 gain code for > unconcatenated system (7,1/2) is still of 3.5 dBs. ?? > > http://books.google.es/books?id=yws55Rx1orEC&lpg=PA28&ots=V1tU4L7wbd&dq=voyager%20reed%20solomon&pg=PA27#v=onepage&q=&f=false >
I am sorry but I have srong temptation to call you the idiot. I will probably do it next time. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
> > >JAlbertoDJ wrote: >>>If the target bit error rate is as high as 0.01, you are not going to >>>gain much by using any reasonable coding. You'd be better by using the
>>>direct uncoded modulation, especially if you account for the modem >> >> losses. >> >> 0.01 would be the maximum error permissible. Modem should work from
0.01
>> to below. >> >> Apart from this, in the following graphics, at Pb=0.01 gain code for >> unconcatenated system (7,1/2) is still of 3.5 dBs. ?? >> >>
http://books.google.es/books?id=yws55Rx1orEC&lpg=PA28&ots=V1tU4L7wbd&dq=voyager%20reed%20solomon&pg=PA27#v=onepage&q=&f=false
>> > >I am sorry but I have srong temptation to call you the idiot. I will >probably do it next time. > > >Vladimir Vassilevsky >DSP and Mixed Signal Design Consultant >http://www.abvolt.com > >
I think you should visit to your pshychologist
cpshah99 <cpshah99@rediffmail.com> wrote:

>Sorry to say this but can you please explain why with interleaving the >information is lost.?
Here's an example. Suppose all errors occur in three-bit bursts. Suppose you apply a pseudo-random interleaver. In the interleaved stream, the ability to predict bit errors based on the previous bit is lost. You could assert of course that if you know the interleaver pattern, no information is lost but this may not help you out practically. Steve
On Wed, 30 Sep 2009 23:14:34 +0000 (UTC), spope33@speedymail.org
(Steve Pope) wrote:

>cpshah99 <cpshah99@rediffmail.com> wrote: > >>Sorry to say this but can you please explain why with interleaving the >>information is lost.? > >Here's an example. Suppose all errors occur in three-bit bursts.
The question is how can one suppose such a situation. If you know the channel to that degree then you design a encoder/decoder which takes advantage of that information so you remove that certainty and in the end you're left with an iid source and channel with awgn which is where you have started and which is the main problem to solve. -- Muzaffer Kal DSPIA INC. ASIC/FPGA Design Services http://www.dspia.com
>cpshah99 <cpshah99@rediffmail.com> wrote: > >>Sorry to say this but can you please explain why with interleaving the >>information is lost.? > >Here's an example. Suppose all errors occur in three-bit bursts. >Suppose you apply a pseudo-random interleaver. In the interleaved >stream, the ability to predict bit errors based on the previous >bit is lost. > >You could assert of course that if you know the interleaver >pattern, no information is lost but this may not help you >out practically. > >Steve >
But, you cannot apply a pseudo-random interleaver, you should apply a interleaver type fodney, for example. So you separate the symbols in time transforming a channel with memory to a memoryless one, and thereby enables the random-error-correcting codes to be useful in a burns-noise channel.
JAlbertoDJ wrote:
>> cpshah99 <cpshah99@rediffmail.com> wrote: >> >>> Sorry to say this but can you please explain why with interleaving the >>> information is lost.? >> Here's an example. Suppose all errors occur in three-bit bursts. >> Suppose you apply a pseudo-random interleaver. In the interleaved >> stream, the ability to predict bit errors based on the previous >> bit is lost. >> >> You could assert of course that if you know the interleaver >> pattern, no information is lost but this may not help you >> out practically. >> >> Steve >> > > But, you cannot apply a pseudo-random interleaver, you should apply a > interleaver type fodney, for example. So you separate the symbols in time > transforming a channel with memory to a memoryless one, and thereby enables > the random-error-correcting codes to be useful in a burns-noise channel.
You keep writing burns noise. Do you mean burst noise? Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
>JAlbertoDJ wrote: >>> cpshah99 <cpshah99@rediffmail.com> wrote: >>> >>>> Sorry to say this but can you please explain why with interleaving
the
>>>> information is lost.? >>> Here's an example. Suppose all errors occur in three-bit bursts. >>> Suppose you apply a pseudo-random interleaver. In the interleaved >>> stream, the ability to predict bit errors based on the previous >>> bit is lost. >>> >>> You could assert of course that if you know the interleaver >>> pattern, no information is lost but this may not help you >>> out practically. >>> >>> Steve >>> >> >> But, you cannot apply a pseudo-random interleaver, you should apply a >> interleaver type fodney, for example. So you separate the symbols in
time
>> transforming a channel with memory to a memoryless one, and thereby
enables
>> the random-error-correcting codes to be useful in a burns-noise
channel.
> >You keep writing burns noise. Do you mean burst noise? > >Jerry >-- >Engineering is the art of making what you want from things you can get. >&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533;&#65533; >
Means High levels of noise during a time interval.
Muzaffer Kal  <kal@dspia.com> wrote:

>On Wed, 30 Sep 2009 23:14:34 +0000 (UTC), spope33@speedymail.org
>>Here's an example. Suppose all errors occur in three-bit bursts.
>The question is how can one suppose such a situation. If you know the >channel to that degree then you design a encoder/decoder which takes >advantage of that information so you remove that certainty and in the >end you're left with an iid source and channel with awgn which is >where you have started and which is the main problem to solve.
Except that the three-bit-burst channel has more capacity than a random-error channel with the same bit-error rate. You can do better than just randomizing it and treating it as if it were random. A similar thread came up here not long ago, in which it was discussed that an AWGN channel is the worst possible channel. This is a real effect. Steve
JAlbertoDJ wrote:
>> JAlbertoDJ wrote: >>>> cpshah99 <cpshah99@rediffmail.com> wrote: >>>> >>>>> Sorry to say this but can you please explain why with interleaving > the >>>>> information is lost.? >>>> Here's an example. Suppose all errors occur in three-bit bursts. >>>> Suppose you apply a pseudo-random interleaver. In the interleaved >>>> stream, the ability to predict bit errors based on the previous >>>> bit is lost. >>>> >>>> You could assert of course that if you know the interleaver >>>> pattern, no information is lost but this may not help you >>>> out practically. >>>> >>>> Steve >>>> >>> But, you cannot apply a pseudo-random interleaver, you should apply a >>> interleaver type fodney, for example. So you separate the symbols in > time >>> transforming a channel with memory to a memoryless one, and thereby > enables >>> the random-error-correcting codes to be useful in a burns-noise > channel. >> You keep writing burns noise. Do you mean burst noise? > > Means High levels of noise during a time interval.
Can you cite a reference that uses it that way? Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;