Added technical milestone report and changes to 1st presentation

[4yp.git] / baseband.m

function baseband(rolloff, M, numSymbs)
  %% Set defaults for inputs
  if nargin < 3
    numSymbs = 1000;
  end
  if nargin < 2
    M = 2;
  end
  if nargin < 1
    rolloff = 0.5;
  end

  %% https://www.mathworks.com/help/comm/examples/passband-modulation-with-adjacent-channel-interference.html
  Rsym = 1e6; % symbol rate (sym/sec)

  span = 6; % filter span
  sps = 2; % samples per symbol

  fs = Rsym * sps; % sampling freq (Hz)

  t = (0 : 1 / fs : numSymbs / Rsym + (1.5 * span * sps - 1) / fs)';

  EbN0_db = 0:0.2:10;
  EbN0 = 10 .^ (EbN0_db ./ 10);
  Es = 1;
  Eb = Es / log2(M);
  N0 = Eb ./ EbN0;

  EsN0 = EbN0 .* log2(M);
  EsN0_db = 10 .* log10(EsN0);

  plotlen = length(EbN0);
  ber = zeros(1, plotlen);

  data = randi([0 M - 1], numSymbs, 1);
  modData = pskmod(data, M, 0, 'gray');

  xBaseband = txFilter(modData, rolloff, span, sps);

  for i = 1:plotlen
    snr = EbN0_db(i) + 10 * log10(log2(M)) - 10 * log10(sps);
    noiseEnergy = 10 ^ (-snr / 10);

    yBaseband = awgn(xBaseband, snr, 'measured');

    rBaseband = rxFilter(yBaseband, rolloff, span, sps);

    rSampled = rBaseband(sps*span/2+1:sps:(numSymbs+span/2)*sps);
    demodData = pskdemod(rSampled, M, 0, 'gray');
    [bitErrors, ber(i)] = biterr(data, demodData);
  end

  figure(1);
  clf;

  %% Plot simulated results
  semilogy(EbN0_db, ber, 'r', 'LineWidth', 2);
  hold on;

  theoreticalPSK(EbN0_db, M, 'b', 'LineWidth', 1);
  legend('Simulated', 'Discrete');

  title(strcat(num2str(M), '-PSK with Gray code'));
  grid on;
  xlabel('$E_b/N_0$ (dB)');
  ylabel('BER');

  formatFigure;
end