i try also to code and decoed a random signal and to calculate the BER, but the problem that the code is too slow ,and the code execution can take more than 30 minutes for just few number of bits !!!
this is the code :
clear all
close all
M = 64; % Modulation order
bps = log2(M); % Bits per symbol
EbNo = (2:0.5:10);
pktLen = 100;
%Initialize the bit error rate vector.
ber = zeros(size(EbNo));
%Create System objects for a turbo encoder and decoder pair, where the interleaver indices are supplied as input arguments<
turboEnc = comm.TurboEncoder('InterleaverIndicesSource','Input port');
turboDec = comm.TurboDecoder('InterleaverIndicesSource','Input port', ...
'NumIterations',1);
%Create an AWGN channel System object and an error rate counter System object
awgnChannel = comm.AWGNChannel('NoiseMethod','Variance','Variance',1);
errorRate = comm.ErrorRate;
rate = pktLen/(3*pktLen+4*3);%rate de codeur
for k = 1:length(EbNo)
errorStats = zeros(1,3);
EsNo = EbNo(k) + 10*log10(bps);
snrdB = EsNo + 10*log10(rate); % in dB
noiseVar = 1./(10.^(snrdB/10));
awgnChannel.Variance = noiseVar;
while errorStats(2) < 100 && errorStats(3) < 1e7
% Generate random binary data
data = randi([0 1],pktLen,1);
% Interleaver indices
intrlvrInd = randperm(pktLen);
% Turbo encode the data
encodedData = turboEnc(data,intrlvrInd);
% Modulate the encoded data
modSignal = qammod(encodedData,M,'InputType','bit','UnitAveragePower',true);
% Pass the signal through the AWGN channel
rxSignal = awgnChannel(modSignal);
% Demodulate the received signal
demodSignal = qamdemod(rxSignal,M,'UnitAveragePower',true,'OutputType','llr','NoiseVariance',noiseVar);
% Turbo decode the demodulated signal. Because the bit mapping from the
% demodulator is opposite that expected by the turbo decoder, the
% decoder input must use the inverse of demodulated signal.
rxBits = turboDec(-demodSignal,intrlvrInd);
% Calculate the error statistics
errorStats = errorRate(data,rxBits);
% Save the BER data and reset the bit error rate object
ber(k) = errorStats(1);
reset(errorRate);
end
end
%Plot the bit error rate
fprintf('Bit error rate = %5.2e\nNumber of errors = %d\nTotal bits = %d\n', ...
errorStats)
semilogy(EbNo,ber,'-*')
grid
xlabel('Eb/No (dB)')
ylabel('Bit Error Rate')
I need t know where is the problem , by the way the most function that takes the most of time is in turbodecoder
