cm_sm32.m

数字信号的传输：1、实现滚降系数分别为0

function[pb,ps]=cm_sm32(snr_in_dB)


N=10000;
E=1;
snr=10^(snr_in_dB/10);
sgma=sqrt(E/snr)/2;

s00=[1  0];
s01=[0  1];
s11=[-1 0];
s10=[0 -1];

for i=1:N,
	temp=rand;
	if(temp<0.25),
	    dsource1(i)=0;
	    dsource2(i)=0;
	elseif(temp<0.5),
	    dsource1(i)=0;
	    dsource2(i)=1;
	elseif(temp<0.75),
	    dsource1(i)=1;
	    dsource2(i)=0;
	else
    	    dsource1(i)=1;
	    dsource2(i)=1;
	end;
end;


numofsymbolerror=0;
numofbiterror=0;

for i=1:N,

	n(1)=gngauss(sgma);
	n(2)=gngauss(sgma);
	if((dsource1(i)==0) & (dsource2(i)==0)),
		r=s00+n;

	elseif((dsource1(i)==0) & (dsource2(i)==1)),
		r=s01+n;

	elseif((dsource1(i)==1) & (dsource2(i)==0)),
		r=s10+n;
	else 
		r=s11+n;
	end;

	c00=dot(r , s00);
	c01=dot(r , s01);	
	c10=dot(r , s10);
	c11=dot(r , s11);

	c_max=max([c00 c01 c10 c11]);
	if(c00==c_max)
		decis1=0;decis2=0;
	elseif(c01==c_max)
		decis1=0;decis2=1;
	elseif(c10==c_max)
		decis1=1;decis2=0;
	else
		decis1=1;decis2=1;
	end;
	
	symbolerror=0;
	if(decis1~=dsource1(i)),
		numofbiterror=numofbiterror+1;
		symbolerror=1;
	end;
	
	if(decis2~=dsource2(i)),
		numofbiterror=numofbiterror+1;
		symbolerror=1;
	end;
	
	if(symbolerror==1),
		numofsymbolerror=numofsymbolerror+1;
	end;
end;

ps=numofsymbolerror/N;
pb=numofbiterror/(2*N);