lab2.m

32QAM modulation 3 different kinds of conditions

close all;
SNR_db=[15,20,25];
N_symbols = 10000; % Number of symbols in the calculation
M=32;
N_samples_per_symbol=8;
%genere date dans l,alphabet M-aire
x=randsrc(N_symbols,1,0:M-1);
y=qammod(x,M,0,'gray');

%Partie A
for i=1:3
    ybruit=awgn(y,SNR_db(i),'measured');
    scatterplot(ybruit); title(['Signal modul? plus bruit SNR= ',int2str(SNR_db(i))]);
end
%partie B
for i=1:3
    ytx=rectpulse(y,N_samples_per_symbol);
    yrx=awgn(ytx,SNR_db(i),'measured');
    ymf=intdump(yrx,N_samples_per_symbol);
    scatterplot(ymf);title(['Signal pulse rectangulaire Recu SNR= ',int2str(SNR_db(i))]);
    x_estimate=qamdemod(ymf,M,0,'gray');
end

%calcul du filtre
[ys, ts] = rcosine(1,N_samples_per_symbol, 'fir/sqrt', 0.3, 3);

for i=1:3
    [yc, tc] = rcosflt(y, 1, N_samples_per_symbol, 'filter', ys);
    yc_bruit=awgn(yc,SNR_db(i),'Measured');
    [yr, tr] = rcosflt(yc_bruit, 1, N_samples_per_symbol, 'filter/Fs', ys);
    yrf=downsample(yr(49:(length(yr)-48)),N_samples_per_symbol);
    scatterplot(yrf);title(['Signal avec rcosine Recu SNR= ',int2str(SNR_db(i))]);
    x_estimate=qamdemod(yrf,M,0,'gray');
end