lms.m

水声通信中的psk方法

% simulation of Adaptive Equalization LMS
clear all
N=2000;
K=5;%%%抽头个数为2*K＋1
% W=3.1
% n=[1,2,3];
% actual_isi=0.5*(1+cos(2*pi*(n-2)/W));
h=[1,zeros(1,6),0.60346,zeros(1,5),0.62736];%%%10Km信道（码元宽度为1Ms的情况）
snr=20;
delta=0.005;%%% 迭代步长，比较0.01，0.002的情况
Num_of_realizations=100;
mse_av=zeros(1,N-2*K);
for j=1:Num_of_realizations,
    info=1-2*randint(1,N);
%      y=conv(actual_isi,info);
      y=filter(h,1,info);
    noise=randn(1,length(y))/10.^(snr/10);
    y=y+noise;
    estimated_c=zeros(1,2*K+1);
    for k=1:N-2*K,
        y_k=y(k:k+2*K);
        z_k=estimated_c*y_k.';
        e_k=info(k)-z_k;
        estimated_c=estimated_c+delta*e_k*y_k;
        mse(k)=e_k^2;
    end;
    mse_av=mse_av+mse;
end
mse_av=mse_av/Num_of_realizations;
t=1:N-2*K;
% semilogy(t,mse_av)
plot(mse_av);
xlabel('迭代次数');
ylabel('MSE');
grid on ;
hold on