bpsk_test1.m

matlab bpsk调制程序

%%%%% 该仿真程序是BPSK在AWGN信道下的调制解调性能验证实例 %%%%%%%%%%%%
%%%%% 该BPSK调制解调是忽略了载波调制与发送、接收基带成形的 %%%%%%%%%
%%%%%% 根据程序框架补充完程序并仿真 %%%%%%%%%%%%%%%%%%%%%%%
clc
clear all;
EbN0dB=1:10;%设定信噪比
errLimit=50;%设定每个信噪比下循环终止统计错误数
N=256;      %祯长
frame=3;  %祯数
cp=32;    %保护间隔
alpha1=0.6;
alpha2=0.2;
alpha3=0.2;
for ii=1:length(EbN0dB)
    errCount=0;
    totalN=0;
    sigma2(ii)=1/(2*(10^(EbN0dB(ii)/10)));%AWGN信道噪声方差与信噪比的关系
    while errCount<errLimit
        for count=1:frame
        source=rand(1,N)>0.5;
        for i=1:N/2;%产生比特信源
        if [source(2*i-1),source(2*i)]==[1,1]
            trans(i)=1+j;
        elseif [source(2*i-1),source(2*i)]==[0,1];
            trans(i)=-1+j;
        elseif [source(2*i-1),source(2*i)]==[0,0];
            trans(i)=-1-j;
        elseif  [source(2*i-1),source(2*i)]==[1,0];
            trans(i)=1-j;
        end
        end           
        inicount(count,:)=[source(1,1:N)];        
        transi(count,:)=[trans((N/2-cp+1):N/2),trans];
        end
        %拼成一序列
        inicounti=[inicount(1,:),inicount(2,:),inicount(3,:)];
        inicounti=reshape(inicounti,1,frame*N);        
        transdata=[transi(1,:),transi(2,:),transi(3,:)];
        transdata=reshape(transdata,1,frame*(N/2+cp));  
        %傅立叶反变换
        transdata=sqrt(frame*(N+cp))*ifft(transdata);        
        %构建信道特性模型
        r1=sqrt(0.5)*(randn(1,frame*(N/2+cp))+j*randn(1,frame*(N/2+cp)));        
        r2=sqrt(0.5)*(randn(1,frame*(N/2+cp))+j*randn(1,frame*(N/2+cp)));
        r3=sqrt(0.5)*(randn(1,frame*(N/2+cp))+j*randn(1,frame*(N/2+cp)));      
        %channel=[alpha1*r1 alpha2*r2 alpha3*r3];
         channel=[0.8,0.1,0.1];
        %构建延时模型
        receiver=conv(transdata,channel);        
        receiver= receiver(1:frame*(N/2+cp))+sqrt(sigma2(ii))*randn(1,frame*(N/2+cp))*(1+j);
        receiver=(1/sqrt(frame*(N/2+cp)))*fft(receiver);
        %加信道噪声,如果是衰落信道，信号模型为y=k*x+n
        %解调     
         receiveri(1,:)=[receiver(1,33:160)];        
         receiveri(2,:)=[receiver(1,193:320)];
         receiveri(3,:)=[receiver(1,353:480)];      
         receiver=[receiveri(1,:),receiveri(2,:),receiveri(3,:)];
         receiver=reshape(receiver,1,frame*N/2);
        for i=1:frame*N/2
        if  real(receiver(i))>0 && imag(receiver(i))>0;
                demodata(2*i-1)=1;
                demodata(2*i)=1;
        elseif real(receiver(i))<0 && imag(receiver(i))>0;
                demodata(2*i-1)=0;
                demodata(2*i)=1;
        elseif real(receiver(i))<0 && imag(receiver(i))<0;
                demodata(2*i-1)=0;
                demodata(2*i)=0;
        elseif real(receiver(i))>0 && imag(receiver(i))<0;
                demodata(2*i-1)=1;
                demodata(2*i)=0;
        end
        end
        demodata;
        %错误统计      
        for i=1:N*frame
        temp=sum(abs(inicounti(i)-demodata(i)));       
        errCount=errCount+temp;
        end
        totalN=totalN+N*frame;
    end
    errCount
    ber(ii)=errCount/totalN;
end
ber
%仿真性能曲线
semilogy(EbN0dB,ber,'-o');
hold on;
grid on;
%理论性能曲线
berthe=berawgn(EbN0dB,'psk',2,'nodiff');
semilogy(EbN0dB,berthe,'-*');