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curve of BER in ldpc codes in matlab

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electronical

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hello every body.
I wrote a plan for ldpc code an get these result but it is different the result that recieved from papaers.can any boby tell me why the result is different?


I wrote these code for n=1210 and frame_num=2000, code rate=0.5;
I used these code for channel
[m,n]=size(H);
sigma=sqrt(10^(-SNRindB1/10));
msg = randint(1,n-m);
c=rem(msg*G,2);
modObj = modem.pskmod('M',2,'InputType','Bit');
modulatedsig = modulate(modObj, c);
receivedsig = awgn(modulatedsig, SNRindB1(I), 0); ...
% Compute log-likelihood ratios (AWGN channel)
demodObj = modem.pskdemod(modObj,'DecisionType','LLR', ...
'NoiseVariance',sigma);
LLR = demodulate(demodObj, receivedsig);

and I expect nearly these result(fast QC codes figure) :at low value SNR ,bit error rate value be about 10^(-1)
 

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iamjin

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can u write BER performance of non binary LDPC min sum decoding???pls help me....i tried a lot..
 

electronical

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hi. I just worked on binary decoding
 
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iamjin

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it differs from binary....
 

cwjcwjcwj

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Don't get what you mean. We normally compare BER at 10^-5. If you have a simulation results similar to the paper one at 10^-3 to 10^-5. Then, likely you're doing something right. Bear in mind, BER of coded system is often worse than uncoded system at low SNR.
 

Mohamedabuhelala

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Hello every body,
any one can help me how to write a code can plot y axis in log scale and x axis in normal scale.

thanks,

- - - Updated - - -

What i am trying to say is i've got results displayed for BER using matlab simulink but i don't know how to plot curve of BER.

i would be so appreciated if someone could help out,

thanks
 

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