function wiener_eval(N, SNR, sigm)

close all;

USE_TD = 0;

s = exp(j*4*pi.*(0:N-1)'/N);
h = -exp(j*4*pi.*(0:N-1)'/N) .* (1+(0.5 - 0.5*cos(2*pi.*(0:N-1)'/N)));
r = awgn(h.*s, SNR);

hr = r./s;

if USE_TD
[ss, gs, rxy, ryy] = wiener_td(s, r, sigm);
ss = ss./abs(ss);

[hs, gh, rxyh, ryyh] = wiener_td(h, hr, sigm);

figure
plot(rxy); grid; legend('rxy');
figure
plot(ryy); grid; legend('ryy');

else
[ss, gs] = wiener_fd(s, r, sigm);
ss = ss./abs(ss);

[hs, gh] = wiener_fd(h, hr, sigm);
end

figure;
subplot(2, 1, 1)
plot(0:N-1, abs(h), 'b-', 0:N-1, abs(hr), 'g-', 0:N-1, abs(hs), 'r-'); grid; legend('|h|', '|h_{r}|', '|h_{s}|');
subplot(2, 1, 2)
plot(0:N-1, angle(h), 'b-', 0:N-1, angle(hr), 'g-', 0:N-1, angle(hs), 'r-'); grid; legend('phi(h)', 'phi(h_{r})', 'phi(h_{s})');

figure;
plot(real(s), imag(s), 'bO', real(r), imag(r), 'rx', real(ss), imag(ss), 'm+'); grid; legend('s', 'r', 'W*r');

figure;
plot(real(gs), imag(gs), 'b+'); grid; legend('gh');

figure;
plot(abs(gh)); grid; legend('|gs|');

function h = channel(N, L, phi_max, omega_d_max, delay_max)
k = 1;      % time
for l=1:L   % frequency
    hsum = 0;
    for n=1:N
        delay_n = delay_max*(1+fix(rand));
        omega_n = omega_d_max*(1 - 2*rand());
        phi_n = phi_max*pi*(1 - 2*rand());
        hsum = hsum + exp(j*0*(phi_n+2*pi*omega_n*k + 2*pi*delay_n/L*l))
    end
    h(l,:) = 1/sqrt(N) * hsum;
end