rec_fromphase2.m

用MATLAB实现MIMO系统盲辨识

%function [look2,ls_error]=rec_fromphase2(theta2,NF,N,Index)
function [look2,ls_error]=rec_fromphase_part(theta2,NF,N,Index,look_true)

% recovers the sequence based on its length (N) and its phase theta2, which
%might be known within a linear phase component

%
%  This program is verified by phase_test.m
%  phase_test.m was designed by Binning Chen on August 4, 1999
%

NO_DELAY=1;

theta2=theta2(:)';

ls_error=[];

nloop=1;
check=100;

for nn=-N:N
   
   PHI1=zeros(1,length(Index));
   phi1=zeros(1,length(Index));
   
   psi1=theta2+2*pi/NF*[0:NF-1]*nn;  % theta2 plus linear phase
   psi1=reshape(psi1,NF,1);
   
   if (abs(check) > 0. )
      Lpos=N-1;
		vec1=[1:Lpos];
		pies1=(2*pi/NF)*[0:NF-1]'*vec1;
		for jj=1:length(vec1)
         ang1(Index,jj)=psi1(Index);
		end
      PHI1=sin(pies1(Index,:)+ang1(Index,:));
      phi1=-sin(psi1(Index));
		look2=inv((PHI1)'*PHI1)*(PHI1)'*phi1;
		look2=[1 look2(1:Lpos)'];
		[lk,ll]=max(abs(look2));
		look2=look2/look2(ll);
		rec=look2;
		LOOK=fft(look2,NF);
      RE=fft(rec,NF);
%      check=mean((detrend(phase(RE))-detrend(theta2)).^2); %% Wrong !!!!!!!!!
      check=mean((detrend(phase(RE)-unwrap(theta2))).^2);
      ls_error=[ls_error log10(check)];	
      REC(nloop,:)=rec;
      NN(nloop)=nn;
      nloop=nloop+1;
   end

   look2=rec;
end     % End of "for nn=-N:N"

[lsm, ls_index]=min(ls_error);
delay=ls_index-N-1;

if NO_DELAY
   ls_index=N+1;
end


look2=REC(ls_index,:);
shift=NN(ls_index);