%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%RLS自适应滤波器性能分析
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
clear
clc
close all
%%%%%%%%%%%%%%参数设置%%%%%%%%%%%%%%%%%%%%%%%
w=2.9;
forget_factor=0.995;
variance_v=0.001;
repeat_times=200;
iteration_times=500;
filt_len=13;
delay=fix(filt_len/2)-1;
%%%%%%%%%%%%%%%%%%%%变量及数组初始化%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Chan_factor=(1+cos(2*pi*([1:1:3]-2)/w))/2;
Square_err=zeros(repeat_times,iteration_times);
%%%%%%%%%%%%%外循环，重复做repeat_times次实验，平均值%%%%%%%%%%%%%%%%
for loop1=1:repeat_times
%%%%%%%%%%%%%%内循环变量及数组初始化%%%%%%%%%%%%%%%%%%%%%%%%
Source=zeros(iteration_times,1);
W=zeros(filt_len,1);
P=eye(filt_len);
Pi=zeros(filt_len,1);
K=zeros(filt_len,1);
%%%%%%%%%%%%%内循环，做iteration_times次迭代%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for i=1:iteration_times
%%%%%%%%%%%%%%信源，产生等概率分布的正负1%%%%%%%%%%%%%%%%%%%%%%%%%%%%
if rand<0.5
Source(i)=-1;
else
Source(i)=1;
end
end
%%%%%%%%%%%%%%信道，滤波和加噪声%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Revdata=filter(Chan_factor,1,Source)+randn(iteration_times,1)*sqrt(variance_v);
%%%%%%%%%%%%%%均衡器，基于LMS算法%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for loop2=1:iteration_times-filt_len+1
U=Revdata(loop2:loop2+filt_len-1);
d=Source(loop2+delay);
Pi=P*U;
K=Pi/(forget_factor+U'*Pi);
e=d-W'*U;
W=W+K*e;
P=P/forget_factor-K*U'*P/forget_factor;
Square_err(loop1,loop2)=e.^2;
end
end
%%%%%%%%%%%%%%作图，显示结果%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Square_err_mean=sum(Square_err(:,:))/repeat_times;
semilogy(Square_err_mean);
figure(2);
stem(W);
