format long
clear all;

r=2/3
H = dvbs2ldpc®;
%e=0
% spy(H); % Visualize the location of nonzero elements in H.

% Construct a default LDPC encoder object
henc = fec.ldpcenc(H);

for SNRdB = 0

for n=1:100;
% Generate a random binary message
msg = randint(1,henc.NumInfoBits,2);

% Encode the message
codeword = encode(henc, msg);

% Verify the parity checks (which should be a zero vector)
paritychecks = mod(henc.ParityCheckMatrix * codeword', 2);

hdec = fec.ldpcdec(H);

% Construct a BPSK modulator object
modObj = modem.pskmod('M',2,'InputType','Bit');

% Modulate the signal (map bit 0 to 1 + 0i, bit 1 to -1 + 0i)
modulatedsig = modulate(modObj, codeword);

% Noise parameters

sigma = sqrt(10^(-SNRdB/10));

% Transmit signal through AWGN channel
receivedsig = awgn(modulatedsig, SNRdB, 0); % Signal power = 0 dBW

% % Visualize received signal
% scatterplot(receivedsig)

% Construct a BPSK demodulator object to compute
% log-likelihood ratios
demodObj = modem.pskdemod(modObj,'DecisionType','LLR', ...
'NoiseVariance',sigma^2);

% Compute log-likelihood ratios (AWGN channel)
llr = demodulate(demodObj, receivedsig);

% Decode received signal
decodedmsg = decode(hdec, llr);

N_err=nnz(decodedmsg-msg);

% % Actual number of iterations executed
% disp(['Number of iterations executed = ' ...
% num2str(hdec.ActualNumIterations)]);
% % Number of parity-checks violated
% disp(['Number of parity-checks violated = ' ...
% num2str(sum(hdec.FinalParityChecks))]);
% % Compare with original message
% disp(['Number of bits incorrectly decoded = ' ...
% num2str(N_err)])


a(n)=N_err; % Общее количество ошибок

end

BER=sum(a)/(n*henc.NumInfoBits)


end
BER
FER=(nnz(a))/n