Code covered by the BSD License

# Contemporary Communications Systems Matlab Files

### Omar Ruiz (view profile)

Matlab Files in this book

[p]=smldP511(snr_in_dB)
```function [p]=smldP511(snr_in_dB)
% [p]=smldP511(snr_in_dB)
%		SMLDP511  simulates the probability of error for the given
%   		snr_in_dB, signal-to-noise ratio in dB, for the system
%   		described in Illustrated Problem 5.11.
M=4;				   	% quaternary biorthogonal signaling
E=1;
SNR=exp(snr_in_dB*log(10)/10);	   	% signal-to-noise ratio per bit
sgma=sqrt(E^2/(4*SNR));  	   	% sigma, standard deviation of noise
N=10000;	 		   	% number of symbols being simulated
% generation of the quaternary data source
for i=1:N,
temp=rand;   	      		% uniform random variable over (0,1)
if (temp<0.25),
dsource(i)=0;
elseif (temp<0.5),
dsource(i)=1;
elseif (temp<0.75),
dsource(i)=2;
else
dsource(i)=3;
end
end;
% detection, and error probability computation
numoferr=0;
for i=1:N,
% the matched filter outputs
if (dsource(i)==0)
r0=sqrt(E)+gngauss(sgma);
r1=gngauss(sgma);
elseif (dsource(i)==1)
r0=gngauss(sgma);
r1=sqrt(E)+gngauss(sgma);
elseif (dsource(i)==2)
r0=-sqrt(E)+gngauss(sgma);
r1=gngauss(sgma);
else
r0=gngauss(sgma);
r1=-sqrt(E)+gngauss(sgma);
end;
% detector follows
if (r0>abs(r1)),
decis=0;
elseif (r1>abs(r0)),
decis=1;
elseif (r0<-abs(r1)),
decis=2;
else
decis=3;
end;
if (decis~=dsource(i)),     		% If it is an error, increase the error counter.
numoferr=numoferr+1;
end;
end;
p=numoferr/N;	               		% bit error probability estimate```