mvdr.m

本文提出在数字移动通信中子带滤波器组处理可以提高不同阵元信号的相关性

%function StandardLMS()
close all
clear;
clc;


Num_snap_shot=200;          %有用信号长度
Num_element=7;                 %阵元数
rou=0.5;               %阵元间距
SNR=10;                 %信噪比 

Theta_im=[70 50 90 110 100 130];
% Theta_im=[70 50 90 110 150 130];
Theta_im=[70 50 90];
Theta_im=[70 55 85];
Theta_im=[70 60 80];
% Theta_im=[70 60 80 90 50];
Doa_signal_desired=Theta_im(1);               %有用信号到达角
Doa_signal_interfere=Theta_im(2:end);
Num_int=length(Doa_signal_interfere);
signal_desired_steervector=SteerVectGen(Doa_signal_desired,Num_element,rou,'linear','arrayaxis');%有用信号导向矢量

signal_desired = sqrt(2)*randsrc(1,Num_snap_shot,[1 -1],1e6); % 有用信号数据
refSig=signal_desired;%参考信号
JNR=0;
JNR=sqrt(10.^(JNR/10)*2);


arrayOutput1=kron(signal_desired,signal_desired_steervector);%期望用户信号天线阵输出
arrayOutput2=0;
for kk=1:Num_int
    signal_interfere = JNR*randsrc(1,Num_snap_shot,[1 -1],kk); %干扰信号数据
    signal_interfere_steervector=SteerVectGen(Doa_signal_interfere(kk),Num_element,rou,'linear','arrayaxis');%干扰信号导向矢量
    arrayOutput2=arrayOutput2+kron(signal_interfere,signal_interfere_steervector);
end
arrayOutput3=arrayOutput2+arrayOutput1;
arrayOutput=awgn((arrayOutput1).',SNR,'measured').';%加入白高斯噪声
X=arrayOutput+arrayOutput2;%在天线阵输出信号中加入干扰信号

%MVDR法求权值
Matrix_relative_X=X*X'/Num_snap_shot;
Gain_ctrl=10;
Matrix_relative_X=Matrix_relative_X+Gain_ctrl*eye(Num_element);%天线阵输出信号的协方差矩阵
% w=inv(Matrix_relative_X)*signal_desired_steervector/(signal_desired_steervector'...
%        *inv(Matrix_relative_X)*signal_desired_steervector);%求权值
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
[Ux,Sx] = svd(Matrix_relative_X);
S_x=diag(Sx);
Rxinv=zeros(Num_element);
for ii=1:Num_element
    Rxinv=Rxinv+1/S_x(ii)*Ux(:,ii)*Ux(:,ii)';
end
w=Rxinv*signal_desired_steervector/(signal_desired_steervector'...
       *Rxinv*signal_desired_steervector);
%显示SMI算法的方向图
figure;
theta=0:180;
pat=SteerVectGen(theta,Num_element,rou,'linear','arrayaxis');
pat1=w'*pat;
pat1=20*log10(abs(pat1));
pat1=pat1-max(pat1);
% Adptive_linear_array(0,rou,Num_element,7, w);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
vir=2*Num_element-1;
SOI_steerK=SteerVectGen(Doa_signal_desired,vir,rou,'linear','arrayaxis');
Scan_mat=SteerVectGen(theta,vir,rou,'linear','arrayaxis');;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
I_sig_sum=X;
I_sig_sum_con=flipud(conj(I_sig_sum(2:end,:)));
Z=[I_sig_sum_con;I_sig_sum];
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Rzz=Z*Z'/Num_snap_shot;
Gain_ctrlz=mean(diag(Rzz));
Gain_ctrlz=10;
Rzz=Rzz+Gain_ctrlz*eye(vir);
% wz=inv(Rzz)*SOI_steerK/(SOI_steerK'...
%        *inv(Rzz)*SOI_steerK);%求权值
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
[U,S] = svd(Rzz);
% S_f=diag(S+Gain_ctrl*eye(vir));
S_f=diag(S);
Rinv=zeros(vir);
for ii=1:vir
    Rinv=Rinv+1/S_f(ii)*U(:,ii)*U(:,ii)';
end
wz=Rinv*SOI_steerK/(SOI_steerK'...
       *Rinv*SOI_steerK);
wz=U(:,1:(Num_int+1))*U(:,1:(Num_int+1))'*wz;
pat3=wz'*Scan_mat;
pat3=20*log10(abs(pat3));
pat3=pat3-max(pat3);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
pat2=SOI_steerK'*Scan_mat;
pat2=20*log10(abs(pat2));
pat2=pat2-max(pat2);
%%%%%%%%%%%%
% figure
% plot(theta,pat2);
% title('MVDR算法');
% grid on;hold on
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5
Huang=12;
figure;
h_ap=axes('FontSize',Huang,'FontName','Times New Roman');
set(get(h_ap,'Xlabel'),'String','\it\theta\rm/deg','FontName','Times New Roman','FontSize',Huang);
set(get(h_ap,'Ylabel'),'String','波束图/dB','FontName','Times New Roman','FontSize',Huang);
kp(1)=line(theta,pat1,'color','r',...
    'linewidth',2,'marker','none','markersize',8,'lineStyle','-');hold on;grid on;
kp(2)=line(theta,pat3,'color','b',...
    'linewidth',2,'marker','none','markersize',8,'lineStyle','--');hold on;grid on;
legend(kp,'MVDR','非圆MVDR')
axis tight;box off;%grid off
hold off
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%