標題: LDPC編碼學(xué)習(xí) Matlab程序 [打印本頁]
作者: zy2012010201    時間: 2017-5-25 11:39
標題: LDPC編碼學(xué)習(xí) Matlab程序
LDPC非常好用的工具。


Matlab程序源程序如下:
  1. %--------------------------------------------------------------------------
  2. %-----Chamitha-de-Alwis----------------------------------------------------
  3. %-----University-of-Surrey-------------------------------------------------
  4. %-----chamithadealwis@hotmail.com------------------------------------------
  5. %--------------------------------------------------------------------------

  7. clear
  8. clc
  9. clear

  11. %--------------------------------------------------------------------------
  12. %-----Set-Simulation-Parameters--------------------------------------------
  13. %--------------------------------------------------------------------------

  15. snrs = [10 13 15];      %SNR values
  16. codeRate = 9/10; %Possible values for codeRate are 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 8/9, and 9/10. The block length of the code is 64800
  17. mod_order = 4;  %PSK Modulation Order
  18. frames = 2500;  %Number of frames (fame size is 64800 bits) to be simulated

  20. %--------------------------------------------------------------------------

  22. rounds = size(snrs,2);

  24. messageLength = round(64800*codeRate);

  26. for run = 1:1:rounds

  28. framepattern = [];   
  29.    
  30. snrvalue = snrs(run);

  32. H = dvbs2ldpc(codeRate);

  34. %spy(H);   % Visualize the location of nonzero elements in H.

  36. errors = 0;

  38. hEnc = comm.LDPCEncoder(H);
  39. hMod = comm.PSKModulator(mod_order, 'BitInput',true);
  40. hChan = comm.MIMOChannel('MaximumDopplerShift', 0, 'NumTransmitAntennas',1,'NumReceiveAntennas',1, 'TransmitCorrelationMatrix', 1, 'ReceiveCorrelationMatrix', 1, 'PathGainsOutputPort', true);
  41. hAWGN = comm.AWGNChannel('NoiseMethod','Signal to noise ratio (SNR)','SNR',snrvalue);
  42. % hDemod = comm.PSKDemodulator(4, 'BitOutput',true,'DecisionMethod','Approximate log-likelihood ratio',...
  43. %                              'Variance', 1/10^(hChan.SNR/10));
  44. hDemod = comm.PSKDemodulator(4, 'BitOutput',true,'DecisionMethod','Approximate log-likelihood ratio');                        
  45. hDec = comm.LDPCDecoder(H,'DecisionMethod', 'Soft decision');
  46. %hError = comm.ErrorRate;
  47. for counter = 1:frames
  48.     receiveddataBits = [];
  49.     data           = logical(randi([0 1], messageLength, 1));
  50. %    data = randi([0 hMod.ModulationOrder-1], messageLength, 1);
  51.     encodedData    = step(hEnc, data);


  54.    
  55.    
  56.     modSignal      = step(hMod, encodedData);
  57.    
  58.    
  59.     % Transmit through Rayleigh and AWGN channels
  60.     [chanOut, pathGains] = step(hChan, modSignal);  
  61.     receivedSignal = step(hAWGN, chanOut);
  62.     demodSignal    = step(hDemod, receivedSignal);
  63.     receivedBits   = step(hDec, demodSignal);
  64.     %errorStats     = step(hError, data, receivedBits);
  65.    
  66.     for i=1:1:messageLength
  67.         if receivedBits(i,1) >= 0
  68.             receiveddataBit = 0;
  69.         else
  70.             receiveddataBit = 1;
  71.         end
  72.         receiveddataBits = [receiveddataBits; receiveddataBit];
  73.     end
  74.    
  75.     newErrors = nnz(receiveddataBits-data);
  76.     errors = errors + newErrors;
  77.     if newErrors == 0
  78.         addFramepattern = 1;
  79.     else
  80.         addFramepattern = 0;
  81.     end
  82.     framepattern = [framepattern addFramepattern];
  83.    
  84.     clc
  85.     run
  86.     counter
  87.     errors
  88.     code_errors = (size(framepattern,2) - nnz(framepattern));
  89.     code_errors
  90. end

  92. SumErrors(run) = errors;
  93. ……………………

  95. …………限于本文篇幅 余下代碼請從51黑下載附件…………
復(fù)制代碼

所有資料51hei提供下載:
LDPC_AWGN.zip (2.17 KB, 下載次數(shù): 32)




作者: 12345678999999    時間: 2018-6-5 01:06
誤碼率信噪比曲線出來結(jié)果不正確為什么？



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