Desktop3.zip_direct sequence ber_干扰 误码率_干扰 误码率_扩频通信_误码率

clc; clear; r=round(rand(1,5000)); %产生5000个随机码元 r=2*r-1; %码序列变为双极性 SNR=-10:1:0; % 信噪比 L=length(r); for m=10:20:50 %扩频增益的类型 a=repmat(r,1,m); b=(reshape(a,L,m))'; x=reshape(b,1,L*m); len=length(x); x_code=sign(mgen(19,11,len)-0.5); msout=x.* x_code; % 已扩频信号 %信道噪声 for SNR1=1:11 Eb = 1; N0= Eb/(10^((SNR1-11)/10)); sig=msout+sqrt(N0)*randn(size(msout)); for i=1:L A=randi([1,3],1,1); for g=1:m t=(i-1)*m+g; sig(t)=sig(t)+A*sin(t); end end msint=sig.*x_code; %开始解扩 Err=0; for j=1:L y=0; for pp=1:m y=y+msint(m*j+pp-m); end z=y/m; %解扩得到用户信码 if z>0 z=1; else z=-1; end if z~=r(j) %用户错误计数 Err=Err+1; end end BER(m,SNR1)=Err/L; % 误码率实际值 end end figure semilogy([-10:0],BER(10,:),'b-*'); % text(0,5.000000e-004,' \leftarrow Gain=10','FontSize',10); hold on semilogy([-10:0],BER(30,:),'y-*'); % text(-6,3.000000e-003,' \leftarrow Gain=30','FontSize',10); hold on semilogy([-10:0],BER(50,:),'r-*'); % text(-9,5.750000e-003,' \leftarrow Gain=50','FontSize',10); legend('Gain=10','Gain=30','Gain=50') title('扩频增益与误码率关系曲线') xlabel('信噪比/dB') ylabel('误码率') grid on