addnoise.m

用MATLAB实现MIMO系统盲辨识

function [rx1,rx2]=addnoise(x1,x2,snr)

% ***********************************************
% function [rx1,ix1,rx2,ix2]=addnoise(x1,x2,snr);
%
% ***********************************************

rx1=real(x1);  rx2=real(x2); 
nr1=randn(size(rx1));
nr2=randn(size(rx2));
nr1=nr1-mean(nr1); nr2=nr2-mean(nr2); 

ss1=sum(abs(x1).^2);  ss2=sum(abs(x2).^2);
sw1=ss1/(10^(snr/10));sw2=ss2/(10^(snr/10));

sr1=sum(nr1.^2);      
sr2=sum(nr2.^2);    
nr1=nr1./(sr1^0.5);
nr2=nr2./(sr2^0.5); 

nr1=nr1*((sw1/2)^0.5); 
nr2=nr2*((sw2/2)^0.5);

rx1=rx1+nr1;    
rx2=rx2+nr2;