Dear all; As we know that LDPC used for error correction. What is the correction capability of it, i.e. how many bits the LDPC can correct for certain H.
LDPC correction capability
Started by ●April 11, 2009
Reply by ●April 11, 20092009-04-11
fawzy wrote:> Dear all; > > As we know that LDPC used for error correction. What is the correction > capability of it, i.e. how many bits the LDPC can correct for certain H.For any linear code, the correction capacity is determined by minimum Hamming distance. So, a typical LDPC can correct somewhat 10 bits. Does this answer your stupid question? Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●April 13, 20092009-04-13
> > >fawzy wrote: >> Dear all; >> >> As we know that LDPC used for error correction. What is the correction >> capability of it, i.e. how many bits the LDPC can correct for certainH.> >For any linear code, the correction capacity is determined by minimum >Hamming distance. So, a typical LDPC can correct somewhat 10 bits. Does>this answer your stupid question? > > >Vladimir Vassilevsky >DSP and Mixed Signal Design Consultant >http://www.abvolt.com > >there is no stupid question, there is always stupid answer.
Reply by ●April 13, 20092009-04-13
fawzy wrote:>> >> fawzy wrote: >>> Dear all; >>> >>> As we know that LDPC used for error correction. What is the correction >>> capability of it, i.e. how many bits the LDPC can correct for certain > H. >> For any linear code, the correction capacity is determined by minimum >> Hamming distance. So, a typical LDPC can correct somewhat 10 bits. Does > >> this answer your stupid question? >> >> >> Vladimir Vassilevsky >> DSP and Mixed Signal Design Consultant >> http://www.abvolt.com >> >> > > there is no stupid question, there is always stupid answer.While I know what you mean and generally agree, there in fact are stupid questions. When driving at 60 mph on the freeway to Grandma's house in the woods, a question from the back seat, "Are we there yet?" is stupid. Anyone capable of framing the question can certainly provide the answer. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●April 14, 20092009-04-14
Reply by ●April 14, 20092009-04-14
It is true under the assumption that a maximum likelihood decoder is used. Unfortunately, this is not how LDPC code is decoded. (A ML decoder is a NP problem.) For a typical LDPC decoder that uses sum- product decoding algorithm, the answer to this question remains an open research problem. Xiaofei Song On Apr 11, 11:58�am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> wrote:> fawzy wrote: > > Dear all; > > > As we know that LDPC used for error correction. What is the correction > > capability of it, i.e. how many bits the LDPC can correct for certain H. > > For any linear code, the correction capacity is determined by minimum > Hamming distance. �So, a typical LDPC can correct somewhat 10 bits. Does > this answer your stupid question? > > Vladimir Vassilevsky > DSP and Mixed Signal Design Consultanthttp://www.abvolt.com
Reply by ●April 14, 20092009-04-14
For any linear code, the correction capacity is determined by minimum Hamming distance. This is by definition. However, this is irrelevant for LDPCs, since LDPCs are decoded according to the distance spectrum, and the number of corrected bits does have meaning only in the statistical sense. So, the question is stupid. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com xsong wrote:> It is true under the assumption that a maximum likelihood decoder is > used. Unfortunately, this is not how LDPC code is decoded. (A ML > decoder is a NP problem.) For a typical LDPC decoder that uses sum- > product decoding algorithm, the answer to this question remains an > open research problem. > > Xiaofei Song > > On Apr 11, 11:58 am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> > wrote: > >>fawzy wrote: >> >>>Dear all; >> >>>As we know that LDPC used for error correction. What is the correction >>>capability of it, i.e. how many bits the LDPC can correct for certain H. >> >>For any linear code, the correction capacity is determined by minimum >>Hamming distance. So, a typical LDPC can correct somewhat 10 bits. Does >>this answer your stupid question? >> >>Vladimir Vassilevsky >>DSP and Mixed Signal Design Consultanthttp://www.abvolt.com > >
Reply by ●April 14, 20092009-04-14
No practical code will be decoded based on the distance spectrum. Distance spectrum is only a way that people make use of to analyze the performance of an ensemble of LDPC code. On Apr 14, 11:09�am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> wrote:> For any linear code, the correction capacity is determined by minimum > Hamming distance. This is by definition. > > However, this is irrelevant for LDPCs, since LDPCs are decoded according > to the distance spectrum, and the number of corrected bits does have > meaning only in the statistical sense. > > So, the question is stupid. > > Vladimir Vassilevsky > DSP and Mixed Signal Design Consultanthttp://www.abvolt.com > > xsong wrote: > > It is true under the assumption that a maximum likelihood decoder is > > used. Unfortunately, this is not how LDPC code is decoded. (A ML > > decoder is a NP problem.) For a typical LDPC decoder that uses sum- > > product decoding algorithm, the answer to this question remains an > > open research problem. > > > Xiaofei Song > > > On Apr 11, 11:58 am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> > > wrote: > > >>fawzy wrote: > > >>>Dear all; > > >>>As we know that LDPC used for error correction. What is the correction > >>>capability of it, i.e. how many bits the LDPC can correct for certain H. > > >>For any linear code, the correction capacity is determined by minimum > >>Hamming distance. �So, a typical LDPC can correct somewhat 10 bits. Does > >>this answer your stupid question? > > >>Vladimir Vassilevsky > >>DSP and Mixed Signal Design Consultanthttp://www.abvolt.com
Reply by ●April 14, 20092009-04-14
So what? What are you arguing to? What point are you trying to make? VLV xsong wrote:> No practical code will be decoded based on the distance spectrum. > Distance spectrum is only a way that people make use > of to analyze the performance of an ensemble of LDPC code. > > On Apr 14, 11:09 am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> > wrote: > >>For any linear code, the correction capacity is determined by minimum >>Hamming distance. This is by definition. >> >>However, this is irrelevant for LDPCs, since LDPCs are decoded according >>to the distance spectrum, and the number of corrected bits does have >>meaning only in the statistical sense. >> >>So, the question is stupid. >> >>Vladimir Vassilevsky >>DSP and Mixed Signal Design Consultanthttp://www.abvolt.com >> >>xsong wrote: >> >>>It is true under the assumption that a maximum likelihood decoder is >>>used. Unfortunately, this is not how LDPC code is decoded. (A ML >>>decoder is a NP problem.) For a typical LDPC decoder that uses sum- >>>product decoding algorithm, the answer to this question remains an >>>open research problem. >> >>>Xiaofei Song >> >>>On Apr 11, 11:58 am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> >>>wrote: >> >>>>fawzy wrote: >> >>>>>Dear all; >> >>>>>As we know that LDPC used for error correction. What is the correction >>>>>capability of it, i.e. how many bits the LDPC can correct for certain H. >> >>>>For any linear code, the correction capacity is determined by minimum >>>>Hamming distance. So, a typical LDPC can correct somewhat 10 bits. Does >>>>this answer your stupid question? >> >>>>Vladimir Vassilevsky >>>>DSP and Mixed Signal Design Consultanthttp://www.abvolt.com > >
Reply by ●April 16, 20092009-04-16
Jerry Avins wrote:> fawzy wrote: >> there is no stupid question, there is always stupid answer. > > While I know what you mean and generally agree, there in fact are stupid > questions. When driving at 60 mph on the freeway to Grandma's house in > the woods, a question from the back seat, "Are we there yet?" is stupid. > Anyone capable of framing the question can certainly provide the answer.My answer to that question is always "Yes." It invariably has the intended effect. -- Jim Thomas Principal Applications Engineer Bittware, Inc jthomas@bittware.com http://www.bittware.com (603) 226-0404 x536 Sometimes experience is the only teacher that works - Mike Rosing
