Nested loop, How can i plot a BER performance for different dBs using a nested loop

How can i plot BER vs E_b/N for different signal to noise ratio? Here is mhy code and i have used nested loop but wouldnt be able to see the plot . I am a new user and help needed in it.

clear; clf

Ldata = 20000; %data length in simulation

Lc = 8; %SPreading factor vs data rate

%generate QPSK modulation symbol

data_sym = 2*round(rand(Ldata,1))-1+1i*(2*round(rand(Ldata,1))-1);

jam_data = 2*round(rand(Ldata,1))-1+1i*(2*round(rand(Ldata,1))-1);

%generating a walsh hadamard codes of length 8

Pcode = [1 -1 1 -1 -1 1 -1 1]' ;

%sPread the code

x_in = kron(data_sym, Pcode);

SIR = [5 8 10 20];

noise = randn(Ldata*Lc,1) + 1i*randn(Ldata*Lc,1);

jam_mod = kron(jam_data,ones(Lc,1));

clear jam_data;

[P,x] = pwelch(x_in,[],[],[4096], Lc,'twoside');

%clear jam_mod;

figure(1)

for j = 1:length(SIR)

for i = 1:10

BER = [];

BER_az = [];

Pj = 2*Lc / (10^(SIR(j)/10));

jammer = sqrt(Pj/2)*jam_mod.*exp(1i*2*pi*0.12*(1:Ldata*Lc)).';

[P,x] = pwelch(jammer+x_in,[],[],[4096], Lc,'twoside');

%clear jam_mod;

EB2N(i) = (i-1);

EB2N_num = 10^(EB2N(i)/10);

Var_n = Lc/(2*EB2N_num); %variance

signois = sqrt(Var_n); %standard deviation

awgnois = signois*noise;

y_out = x_in+awgnois+jammer;

Y_out = reshape(y_out,Lc,Ldata).';

clear y_out awgnois;

z_out = Y_out*Pcode;

%decision based on the sign of the samPles

dec1 = sign(real(z_out))+j*sign(imag(z_out));

%comPare against the original data to calcuate BER

BER = [BER;sum([real(data_sym)~=real(dec1);...

imag(data_sym)~=imag(dec1)])/(2*Ldata)];

BER_az = [BER_az;0.5*erfc(sqrt(EB2N_num))];

end

if j==1

figber = semilogy(EB2N,BER_az, 'k-');

hold on;

end

figber = semilogy(EB2N,BER);

clear BER;

clear BER_az;

legend('No jamming','SNR:-5 dB', 'SNR:-8 dB', 'SNR:-10 dB', 'SNR:-20 dB');

set(figber,'Linewidth',2);

xfont=xlabel('E_b/N in dB');

yfont = ylabel('bit error rate');

title('DSSS with sPreading gain 11');

end

Answer 1

[Shraddha Jain]

Hi Lutfeyara,

In order to display individual figure windows, use the figure command just before the semilogy command as,

figure
figber = semilogy(EB2N,BER);