Code covered by the BSD License

MATLAB for Digital Communication

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Won Yang (view profile)

The MATLAB programs in "MATLAB/Simulink for Digital Communication" authored by Won Y. Yang et. al

p=prob_error(SNRbdB,signaling,b,opt1,opt2)
```function p=prob_error(SNRbdB,signaling,b,opt1,opt2)
% Finds the symbol/bit error probability for given SNRbdB (Table 7.1)
%Copyleft: Won Y. Yang, wyyang53@hanmail.net, CAU for academic use only
if nargin<5, opt2 = 'coherent'; end  % opt2='coherent' or 'noncoherent'
if nargin<4, opt1 = 'SER'; end % opt1='SER' or 'BER'
M=2^b; SNRb=10.^(SNRbdB/10);  NSNR=length(SNRb);
if lower(opt2(1))=='c' % ASK coherent --> Eq.(7.1.5)
for i=1:NSNR, p(i)=2*(M-1)/M*Q(sqrt(3*b*SNRb(i)/(M^2-1))); end
if lower(opt1(1))=='b', p = p/b; end
else  % ASK non-coherent -->  Eq.(7.1.22)
if b==1,  for i=1:NSNR, p(i)=exp(-SNRb(i)/4)/2; end;  end
end
elseif signaling(1:3)=='FSK'
tmp=M/2/(M-1);
f5251_=inline('Q(-sqrt(2)*x-sqrt(b*SNRb)).^(2^b-1)','x','SNRb','b');
if lower(opt2(1))=='c' % FSK coherent
if b==1
for i=1:NSNR, p(i)=Q(sqrt(SNRb(i)/2)); end   %Eq.(7.2.9)
else
for i=1:NSNR
p(i) = 1-Gauss_Hermite(f5251_,10,SNRb(i),b)/sqrt(pi);
end
end
else % FSK non-coherent
for i=1:NSNR
p(i)=(M-1)/2*exp(-b*SNRb(i)/4);  tmp1=M-1;
for m=2:M-1
tmp1=-tmp1*(M-m)/m;
p(i)=p(i)+tmp1/(m+1)*exp(-m*b*SNRb(i)/2/(m+1)); % Eq.(7.2.19)
end
end
end
if lower(opt1(1))=='b'&b>1, p = p*tmp; end
elseif signaling(1:3)=='PSK'  % Eq.(7.3.7)
for i=1:NSNR, p(i)=(1+(b>1))*Q(sqrt(b*SNRb(i))*sin(pi/M));  end
if lower(opt1(1))=='b'&b>1, p = p/b; end
elseif signaling(1:3)=='DPS' % DPSK
if b==1  % Eq.(7.4.8)
for i=1:NSNR, p(i)=2*Q(sqrt(b*SNRb(i)/2)*sin(pi/M)); end
else
for i=1:NSNR, p(i)=exp(-SNRb(i)/2)/2; end %Eq.(7.4.9)
if lower(opt1(1))=='b', p = p/b; end
end
elseif signaling(1:3)=='QAM'
L=2^(ceil(b/2)); N = M/L;
for i=1:NSNR
tmpL = 1-2*(L-1)/L*Q(sqrt(3*b/2/(L^2-1)*SNRb(i)));
tmpN = 1-2*(N-1)/N*Q(sqrt(3*b/2/(N^2-1)*SNRb(i)));
p(i) = 1-tmpL*tmpN; % Eq.(7.5.6)
end
if lower(opt1(1))=='b'&b>1, p = p/b; end
end
```