误码率程序及仿真图(共5页)

1、精选优质文档-倾情为你奉上clear all;close all;clcframe=10000;t=0:pi/180:2*pi;source_code=randint(1,500);SNR=0:0.25:10;carrier1=sin(2*pi*t);carrier2=sin(2*pi*t+pi);Carrier=carrier1 carrier2;snr=10.(SNR./10);for loop=1:length(source_code) if source_code(loop)=1 modulated_signal(loop,:)=carrier1; else modulated_sig

2、nal(loop,:)=carrier2; endendModulated=reshape(modulated_signal',1,loop*length(carrier1);Modulated_Information=2*source_code-1;for iteration=1:length(SNR) error=0; for i=1:frame add_noise=awgn(Modulated_Information,SNR(iteration); for address=1:length(add_noise) if add_noise(address)>0 demodul

3、ated(address)=1; else demodulated(address)=0; end if demodulated(address)=source_code(address) error=error+1; end end end Pe(iteration)=error/frame/length(source_code); Pe_theor=(erfc(sqrt(snr).*(1-0.5*erfc(sqrt(snr);endfigure(1)semilogy(SNR,Pe_theor,'Marker','o','Color','

4、;r');grid on;hold on;semilogy(SNR,Pe,'Marker','*','Color','b')% axis(snrdB_min snrdB_max 0.0001 1);xlabel('信噪比');ylabel('误码率');title('BPSK信号最佳接收误码率曲线');legend('理论值','实际值');图4-2 BPSK信号误码率的仿真图function enc_comp=cm_dpske(E,M,map

5、ping,sequence);k=log2(M);N=length(sequence);reminder=rem(N,k);if(reminder=0), for i=N+1:N+k-reminder, sequence(i)=0; end; N=N+k-reminde;end theta=0; for i=1:k:N, index=0; for j=i:i+k-1, index=2*index+sequence(j); end index=index+1; theta=mod(2*pi*mapping(index)/M+theta,2*pi); enc_comp(i+k-1)/k,1)=sq

6、rt(E)*cos(theta); enc_comp(i+k-1)/k,2)=sqrt(E)*sin(theta); end=function p=cm_sm35(SNRindB)N=2000;E=1;snr=10(SNRindB/10);sgma=sqrt(E/(4*snr);for i=1:2*N; temp=rand; if(temp<0.5), dsource(i)=0; else dsource(i)=1; endendmapping=0 1 3 2;M=4;diff_enc_output=cm_dpske(E,M,mapping,dsource);for i=1:N, gsr

7、v1,gsrv2=gngauss(sgma); r(i,:)=diff_enc_output(i,:)+gsrv1,gsrv2;end prev_theta=0; numoferr=0; for i=1:N, theta=angle(r(i,1)+j*r(i,2); delta_theta=mod(theta-prev_theta,2*pi); if(delta_theta<pi/4)|(delta_theta>7*pi/4), decis=0 0; elseif(delta_theta<3*pi/4), decis=0 1; elseif(delta_theta<5*

8、pi/4), decis=1 1; else decis=1 0; end prev_theta=theta; if(decis(1)=dsource(2*i-1)|(decis(2)=dsource(2*i), numoferr=numoferr+1; end; end; p= numoferr/N;=echo onSNRindB1=0:2:12;SNRindB2=0:0.1:12;for i=1:length(SNRindB1), pe=cm_sm35(SNRindB1(i); smld_bit_err_prb(i)=pe; echo off;end;echo on;for i=1:length(SNRindB2), SNR=exp(SNRindB2(i)*log(10)/10); theo_err_prb(i)