Need Source Code for Decoding _Using algorithm
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Message-passing on the binary erasure channel
Code word =[1 0 0 1 0 1]
Y= [1 0 0 x x 1]Procedure DECODE(Y)
I= 0 //Initialization
For i= 1 :n do
Mi=yi
end for
repeatfor j= 1 :m do //Step 1: Check messages
for all i ∈Bj do
if all messages into check j other than M i are known thenend if
end for
end for
for i= 1 :n do //Step 2: Bit messages
if Mi= ‘unknown’thenMi=Ej,i
end if
end if
end forif all Mi known or I =Imax then //Test
Finishedelse
I=I+ 1
end ifuntil Finished
end procedure
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I am working LDPC encoding and decoding for mini project work. With my effort i have completed LDPC encoding but struggling with LDPC decoding.
Message-passing on the binary erasure channel
Code word =[1 0 0 1 0 1]
Y= [1 0 0 x x 1] // x = missing bit, need to find out the missing bit through Message-passing decoding algorithm.
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I am working LDPC encoding and decoding for mini project work. With my effort i have completed LDPC encoding but struggling with LDPC decoding.
Message-passing on the binary erasure channel
Code word =[1 0 0 1 0 1]
Y= [1 0 0 x x 1] // x = missing bit, need to find out the missing bit through Message-passing decoding algorithm.
Can anyone help me in writing C languageLDPC Decoding:Looking for logic using algorithm.-algo-png for decoding procedure. Please give me logic.
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Can anyone help me in writing C languageLDPC Decoding:Looking for logic using algorithm.-algo-png for decoding procedure. Please give me logic.
The logic is available on wikipedia Low-density parity-check code - Wikipedia[^] You haven't written anything yet so have a go at writing the code and I am sure things will dawn on you.
In vino veritas
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The logic is available on wikipedia Low-density parity-check code - Wikipedia[^] You haven't written anything yet so have a go at writing the code and I am sure things will dawn on you.
In vino veritas
I have already know that in Wikipedia, Low-density parity-check code is given but not the logic. I have gone through all the theory parts. Thanks for your logic.
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I have already know that in Wikipedia, Low-density parity-check code is given but not the logic. I have gone through all the theory parts. Thanks for your logic.
If you have gone thru the problem them you should have already realized, you can't decode anything until you first sort out the type of encoding. LDPC isn't one thing it is a verbose description of any number of schemes it is an NP-complete code problem. So you may have read the wikipedia article but you don't understand it. Effectively you just asked us to help us build a vehicle and we don't know if it's a car, boat, truck, train, hovercraft or plane. Look all I can do is point you at GitHub - jontio/LDPC-4Qt: Forward Error Correction using LDPC codes with Qt C++[^] As it says the code on there is too slow and totally useless for any sort of real world use it will just get you to understand LDPC codes.
In vino veritas
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If you have gone thru the problem them you should have already realized, you can't decode anything until you first sort out the type of encoding. LDPC isn't one thing it is a verbose description of any number of schemes it is an NP-complete code problem. So you may have read the wikipedia article but you don't understand it. Effectively you just asked us to help us build a vehicle and we don't know if it's a car, boat, truck, train, hovercraft or plane. Look all I can do is point you at GitHub - jontio/LDPC-4Qt: Forward Error Correction using LDPC codes with Qt C++[^] As it says the code on there is too slow and totally useless for any sort of real world use it will just get you to understand LDPC codes.
In vino veritas
Hi, I have completed my LDPC encoding part and got output. Now i switched over to LDPC decoding part. I know procedure of LDPC decoding very well, but in Coding part i am feel little bit difficult.
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Hi, I have completed my LDPC encoding part and got output. Now i switched over to LDPC decoding part. I know procedure of LDPC decoding very well, but in Coding part i am feel little bit difficult.
If you know it very well, you should be able to write down the steps. Once you have the steps written down, you should then be able to further break them down into logical programming structures. You solve this just like any other programming problem by breaking it down and down until you have a clear understanding of what code needs to be written.
This space for rent
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Hi, I have completed my LDPC encoding part and got output. Now i switched over to LDPC decoding part. I know procedure of LDPC decoding very well, but in Coding part i am feel little bit difficult.
So what form of the decoder are you trying to write? Some I am familiar with, others I am not. I don't claim to know every type of LDPC decoder on the planet. If you haven't chosen one then perhaps read an analysis .. this was done for the DVB-S2 specification [Investigation of LDPC code in DVB-S2]
In vino veritas
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So what form of the decoder are you trying to write? Some I am familiar with, others I am not. I don't claim to know every type of LDPC decoder on the planet. If you haven't chosen one then perhaps read an analysis .. this was done for the DVB-S2 specification [Investigation of LDPC code in DVB-S2]
In vino veritas
I know concepts of message_passing decoding or bit_flipping decoding techniques. So i am trying C codes for message_passing decoding or bit_flipping decoding.
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I know concepts of message_passing decoding or bit_flipping decoding techniques. So i am trying C codes for message_passing decoding or bit_flipping decoding.
Actually i am not getting about the type of decoder concerned with partially parallel or fully serial bcoz I have to implement the LDPC decoder with the help of belief propagation algorithm.In that process i have been provided with a H matrix,code word like [0 0 1 0 1 1] for a 4*6 matrix.The received word is r=[1 0 1 0 1 1] with a cross over probability of p=0.2. Now the steps which i have to follow for computation is as follows:- 1.in the first step using logp/1-p i have to find out the received word and it comes like r=[-1.3863,1.3863,-1.3863,1.3863,-1.3863,1.3863] 2.Since it is a 4*6 matrix M11=r1=-1.3863 and M31=r1=-1.3863 for i=2,M12=r2=1.3863 and M22=r2=1.3863 . . . . for i=6 M36=r6=-1.3863 and M46=r6=-1.3863 3.Extrensic information.It is calculated by using formula E11=log(1+tanh(M12/2)tanh(M14/2)/1-tanh(M12/2)tanh(M14/2)) Like that i have to calculate for eacha nd every node and finally a E matrix has been formed 4.calculation of LLR L1=r1+E11+E31=some value . . . . L6=some value finally on the basis of BPSK scheme Z=[0 0 1 0 1 1] 5.To check if Z is a valid codeword S=Z.H transpose if it comes like [0 0 0 0] then my code word is correct otherwise have to go for next iteration. Please tell me how should i proceed.Its a total mathematical calculation.I am stuck with the point of taking matrix as a input.If i take it as an array also then how should i calculate that tanh calculation.
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Actually i am not getting about the type of decoder concerned with partially parallel or fully serial bcoz I have to implement the LDPC decoder with the help of belief propagation algorithm.In that process i have been provided with a H matrix,code word like [0 0 1 0 1 1] for a 4*6 matrix.The received word is r=[1 0 1 0 1 1] with a cross over probability of p=0.2. Now the steps which i have to follow for computation is as follows:- 1.in the first step using logp/1-p i have to find out the received word and it comes like r=[-1.3863,1.3863,-1.3863,1.3863,-1.3863,1.3863] 2.Since it is a 4*6 matrix M11=r1=-1.3863 and M31=r1=-1.3863 for i=2,M12=r2=1.3863 and M22=r2=1.3863 . . . . for i=6 M36=r6=-1.3863 and M46=r6=-1.3863 3.Extrensic information.It is calculated by using formula E11=log(1+tanh(M12/2)tanh(M14/2)/1-tanh(M12/2)tanh(M14/2)) Like that i have to calculate for eacha nd every node and finally a E matrix has been formed 4.calculation of LLR L1=r1+E11+E31=some value . . . . L6=some value finally on the basis of BPSK scheme Z=[0 0 1 0 1 1] 5.To check if Z is a valid codeword S=Z.H transpose if it comes like [0 0 0 0] then my code word is correct otherwise have to go for next iteration. Please tell me how should i proceed.Its a total mathematical calculation.I am stuck with the point of taking matrix as a input.If i take it as an array also then how should i calculate that tanh calculation.
You have totally lost me ... you are giving me the formulas tanh is a standard C/C++ function (C library function - tanh) You have the matrix coefficents and like you said the E matrix first coefficent is E11=log(1+tanh(M12/2)tanh(M14/2)/1-tanh(M12/2)tanh(M14/2)) So plug the numbers in and calculate your E matrix coefficents You do all your other calculations and then transpose the matrix .. you know C Program to Find Transpose of a Matrix] You need to explain this statement => "how should i calculate that tanh calculation". I simply don't get it tanh is a trig function like sine/cosine/tan and it just needs "#include " and you have it on any C/C++ compiler that meets the oldest C89 standard. You gave me coefficent values above so I know you know what M12,M14 are and you know what a 2 is. So I query why you ask me how do you do the tanh calculation, why didn't you ask me how you do the log calculation? What is the difference between those that is causing your problems?
In vino veritas