ss_pe.m

带汉明码的直接序列变换DSSS

function [p]=ss_Pe(snr_in_dB,Lc,A,w0)
snr=10^(snr_in_dB/10);
sgma=1;
Eb=2*sgma^2*snr;
E_chip=Eb/Lc;
N=1000;
num_of_err=0;
for i=1:N
    temp=rand;
    if(temp<0.5)
        data=-1;
    else
        data=1;
    end;
    for j=1:Lc
        repeated_data(j)=data;
    end;
    for j=1:Lc
         temp=rand;
         if(temp<0.5)
             pn_seq(j)=-1;
         else
             pn_seq(j)=1;
         end
	end;
	tran_sig=sqrt(E_chip)*repeated_data.*pn_seq;
	noise=sgma*randn(1,Lc);
	n=(i-1)*Lc+1:i*Lc;
	interference=A*sin(w0*n);
	rec_sig=tran_sig+noise+interference;
	temp=rec_sig.*pn_seq;
	decision_variable=sum(temp);
	if(decision_variable<0)
        decision=-1;
	else
        decision=1;
	end;
	if(decision~=data)
        num_of_err=num_of_err+1;
	end;
end;
p=num_of_err/N;