[communication] wide band source DOA estimation method based on incoherent signal subspace (ISM)

1 brief introduction

Smart antenna technology is one of the key technologies of the future mobile communication system , It is the research focus in the current communication field . The smart antenna system expands the space domain through the antenna array , Make full use of the resources provided by space expansion , It can effectively improve the system capacity 、 It can provide greater bandwidth and reduce the adverse effects of multipath effect . Direction of arrival (Direction of Arrival,DOA) Estimation is one of the key technologies of smart antenna technology , It can be used to realize space division multiple access 、 Accurate positioning of mobile station, etc .　​

2 Complete code

clc

clear all

close all

N=10;       % The number of elements

L=1000;     

J=10;       % Frequency points

M=10^4;     % Time domain sampling snapshots

f0=100; % Signal center frequency

fs=100;     % Sampling frequency 1000MHZ

SNR=100;    %20dB S / N ratio of 10lg(SNR)

q=zeros(N,(M/L)); 

T=100; % Transmission pulse width 100s

%t=T*[0:1/M:(M-1)/M];% The time point corresponding to the discrete point

B=40;  % FM bandwidth 30MHz

K=B/T;           % Frequency modulation slope

Ts=1/fs;          % Sampling period  

u=0.5;     % Angle of incidence

%2 Generate a signal model

 for n=1:1:N

tao=0.5*(n-1)*u/f0;                  %for  k=1:1:length(t)

 t=linspace(-T/2-tao,T/2-tao,M);

 X(n,:)=SNR*exp(j*2*pi*(f0*t+0.5*K*t.^2));         %X(n,k)=exp(j*2*pi*(f0*(t(k)-0.5*(n-1)*u/(2*f0))+0.5*K*(t(k)-0.5*(n-1)*u/(2*f0)).^2));+0.5*K*t.^2

 end                                 %end

        

     %Xn=sqrt(1/2)*randn(N,M)+j*sqrt(1/2)*rand(N,M);

Xn=wgn(N,M,0,'complex');   

% routine MUSIC Algorithm

Y=X+Xn;% N*M Order matrix                                                               

for m=1:L

  for i=1:N 

    for k=1:(M/L)

    q(i,k,m)=Y(i,(m-1)*J+k);

     end        % Divide into L Submatrix （L*J=M)     

  end 

  p(:,:,m)=abs(fft(q(:,:,m),10));

end 

for i=1:(M/L)    

    for m=1:L

    r(:,m,i)=p(:,i,m);

    end   

end 

for i=1:(M/L)

Rx(:,:,i)=r(:,:,i)*r(:,:,i)'/L;

[F(:,:,i),D(:,:,i)]=eigs(Rx(:,:,i),N-3,'SM');

xa=-1:0.01:1;

n=[0:1:N-1]';

fk=f0-B/2+i*B/10;

    for m=1:length(xa)

        Va=exp(j*pi*fk/f0*xa(m)*n);   

        p0(i,m)=1/(Va'*F(:,:,i)*F(:,:,i)'*Va);    

    end    

end 

 z=zeros(1,length(xa));

for i=1:(M/L)

 z=z+p0(i,:);  % Each row of the matrix is accumulated

end

p1=z/(M/L);

% Make a picture   

plot(xa,10*log10(p1));

title('Classic MUSIC Spectrum');

xlabel('Angle');

ylabel('Spectrum');

grid on;

3 Simulation results

4 reference

[1] Yang can , Hepeiyu , Li Feng , etc. . Based on narrowband signals DOA Estimated wideband coherent signal DOA Research on estimation methods [J]. Journal of Sichuan University ： Natural science edition , 2009, 46(1):7.

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