ss_pe94.m

直接序列扩频通信系统仿真程序

function [p]=ss_Pe94(snr_in_dB,Lc,A,w0);
snr=10^(snr_in_dB/10);
sgma=1;
Eb=2*sgma^2*snr;
E_chip=Eb/Lc;
N=10000;
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
    trans_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=trans_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;