% function ofdm_tx(N_frames)
function [yv xv] = ofdm_tx(mode, bandwidth, N_frames, withData, plot_speed)

close all;

DO_PLOT = (plot_speed > 0);
WITH_RCWIN = 1;
WITH_FREQ_REF = 1;
WITH_TIME_REF = 1;
WITH_GAIN_REF = 1;
WITH_DATA = withData;
DELAY = 100;

M_QAM = 64;
RCWIN_ROLLOFF = 0.125;

% Params
fa = 12000;
T = 1/fa;

[ofdm_params, ofdm_spec_occ] = drm_params(mode, bandwidth);

ofdm_params_mode = ofdm_params.mode
ofdm_spec_occ_kmin = ofdm_spec_occ.kmin
ofdm_spec_occ_kmax = ofdm_spec_occ.kmax

Tu = ofdm_params.nu * T
Tg = ofdm_params.ng * T
Ts = Tu+Tg
Ng = round(Tg*fa)
N = round(Tu*fa)
Ns = round(Ts*fa)
SubCarrierspacing_HZ = fa/N

% TX window
[rcwin Nt wng] = txwin_eval(N, Ng, RCWIN_ROLLOFF);
Nt = Nt

% Source
qlut = qamtable(M_QAM);

k_fft = sqrt(N);
xv = zeros(1, DELAY);
xt = zeros(1, Nt);
x_prefix = zeros(2, Ng);
x_suffix = zeros(2, Ng);

ofdm_spec_occ.kmin
ofdm_spec_occ.kmax
sym_count = 0;
for k=1:N_frames
    X = zeros(N,1);

    % Data
    if WITH_DATA == 1
        data_i = c2i(N, ofdm_spec_occ.kmin:1:ofdm_spec_occ.kmax);
        sym = round(M_QAM*rand(1, length(data_i))+0.5);
        X(data_i) = qlut(sym);
    end;

    if WITH_GAIN_REF == 1
        [ref_c ref_p ref_a] = getRefGain(ofdm_params, ofdm_spec_occ, sym_count);
        bins = c2i(N, ref_c);
        X(bins) = ref_a.*(exp(j*2*pi*ref_p/1024));
    end;

    if (sym_count==0) & (WITH_TIME_REF == 1)
        [ref_c ref_p ref_a] = getRefTime(ofdm_params.mode);
        bins = c2i(N, ref_c);
        X(bins) = ref_a.*(exp(j*2*pi*ref_p/1024));
    end;

    if WITH_FREQ_REF == 1
        [ref_c ref_p ref_a] = getRefFreq(ofdm_params.mode);
        bins = c2i(N, ref_c);
        X(bins) = ref_a.*(exp(j*2*pi*ref_p/1024));
    end;

    X(c2i(N, 0)) = 0;

    % Modulate
    xu = k_fft*ifft(X, N).';
    if WITH_RCWIN == 1
        x_prefix(1,:) = xu(N-Ng+1:N);
        x_suffix(1,:) = xu(1:Ng);

        x_pw = x_suffix(2,:) .* (1-wng) + x_prefix(1,:) .* wng;

        xs = [x_pw xu];

        x_prefix(2,:) = x_prefix(1,:);
        x_suffix(2,:) = x_suffix(1,:);
    else
        xs = [xu(N-Ng+1:N) xu];
    end;
    xv = [xv xs(1:Ng+N)];

    if (DO_PLOT == 1)
%            Xs = fftshift(fft(xs(Ng+1:Ng+N), N)/k_fft);
        Xs = fftshift(X);
        subplot(2, 1, 1)
        plot(0:N-1, abs(Xs(1:N)), '-*'); grid; axis([0 N-1 0 3.0]);
        subplot(2, 1, 2)
        plot(0:N-1, angle(Xs(1:N)), '-*'); grid; axis([0 N-1 -2*pi 2*pi]);
        pause(plot_speed);
    end
    sym_count = mod(sym_count+1, ofdm_params.nspf);
end;
hold off;
grid;

plot(wng); grid;

% Modulate on carrier
xup = upsample(xv, 4);
hlp = FIRCalcLowpass(0.25, 129);
xup = filter(hlp, 1, xup);

yc = exp(j*2*pi.*(0:length(xup)-1)*0.25) .* xup;
yv = real(yc) + imag(yc);

xv = xv.' ./abs(max(xv));
yv = yv'./max(yv);

wavwrite(0.8*yv,4*fa,16,'yv.wav')
wavwrite(0.8*[real(xv) imag(xv)],fa,16,'xv.wav')