capon_sign.m

DOA估计中的Capon方法

clear
clc
Path=3;  %路径总径
sita0=0;
sita1=20;
sita2=40;
sita3=60;
hudu0=sita0*pi/180;
hudu1=sita1*pi/180;
hudu2=sita2*pi/180;
hudu3=sita3*pi/180;

a0=[1;
    exp(-j*pi*sin(hudu0));
    exp(-j*2*pi*sin(hudu0));
    exp(-j*3*pi*sin(hudu0));
    exp(-j*4*pi*sin(hudu0));
    exp(-j*5*pi*sin(hudu0));
    exp(-j*6*pi*sin(hudu0));
    exp(-j*7*pi*sin(hudu0))]
a1=[1;
    exp(-j*pi*sin(hudu1));
    exp(-j*2*pi*sin(hudu1));
    exp(-j*3*pi*sin(hudu1));
    exp(-j*4*pi*sin(hudu1));
    exp(-j*5*pi*sin(hudu1));
    exp(-j*6*pi*sin(hudu1));
    exp(-j*7*pi*sin(hudu1))]
a2=[1;
    exp(-j*pi*sin(hudu2));
    exp(-j*2*pi*sin(hudu2));
    exp(-j*3*pi*sin(hudu2));
    exp(-j*4*pi*sin(hudu2));
    exp(-j*5*pi*sin(hudu2));
    exp(-j*6*pi*sin(hudu2));
    exp(-j*7*pi*sin(hudu2))]

a3=[1;
    exp(-j*pi*sin(hudu3));
    exp(-j*2*pi*sin(hudu3));
    exp(-j*3*pi*sin(hudu3));
    exp(-j*4*pi*sin(hudu3));
    exp(-j*5*pi*sin(hudu3));
    exp(-j*6*pi*sin(hudu3));
    exp(-j*7*pi*sin(hudu3))]


SNRdB=-5;

N=1000
  bit0=2*rem(unidrnd(2,1,N),2)-1;
  sig0=[bit0];
  bit1=2*rem(unidrnd(2,1,N),2)-1;
  sig1=[bit1];
  bit2=2*rem(unidrnd(2,1,N),2)-1;
  sig2=[bit2];
  bit3=2*rem(unidrnd(2,1,N),2)-1;
  sig3=[bit3];
  
 
isi0=[1,0];  
isi1=[0,1];
isi2=[0,1];
isi3=[0,1];

len=1000; %卷积长度
  noise=randn(8,len)/(10^(SNRdB/10));
  
   Rx=zeros(8,8);
    p=zeros(1,90);%绘图用
  

  x0=a0*sig0+noise;
  x1=a1*sig1+noise;
  x2=a2*sig2+noise;
  x3=a3*sig3+noise;
  x=[x0 x1 x2 x3];
   xx=x*x';
    Rx=Rx+xx;

    
    
    %Delay-Combining spatial spectrum
   
    angle=0:0.1:90;
    for i=1:length(angle);
        theta=((i-1)/10)*pi/180;
        
Atheta=[1,exp(-j*pi*sin(theta)),exp(-j*2*pi*sin(theta)),exp(-j*3*pi*sin(theta)),exp(-j*4*pi*sin(theta)),exp(-j*5*pi*sin(theta)),exp(-j*6*pi*sin(theta)),exp(-j*6*pi*sin(theta))].';
        
        Pdelay=Atheta'*Rx*Atheta;

        p(i)=sqrt(Pdelay*Pdelay');
    end
    
    plot(angle,p);