Chromatic dispersion and line width phase noise

[4yp.git] / discretePSK_BER_SNR.m

diff --git a/discretePSK_BER_SNR.m b/discretePSK_BER_SNR.m
index fd8849c..cdff01f 100644 (file)
--- a/discretePSK_BER_SNR.m
+++ b/discretePSK_BER_SNR.m
@@ -1,16 +1,12 @@
-function discretePSK_BER_SNR(M, numBits)
+function discretePSK_BER_SNR(M, numSymbs)
   %% Set defaults for inputs
   if nargin < 2
-    numBits = 1000;
+    numSymbs = 1000;
   end
   if nargin < 1
     M = 2;
   end
 
-  if isOctave()
-    pkg load communications
-  end
-
   EbN0_db = 0:0.2:10;
   EbN0 = 10 .^ (EbN0_db ./ 10);
 
@@ -25,7 +21,7 @@ function discretePSK_BER_SNR(M, numBits)
 
   ber = zeros(1, plotlen);
 
-  data = randi([0, M - 1], 1, numBits);
+  data = randi([0, M - 1], 1, numSymbs);
   txsig = pskmod(data, M, 0, 'gray');
 
   for i = 1:plotlen
@@ -35,35 +31,19 @@ function discretePSK_BER_SNR(M, numBits)
     [bitErrors, ber(i)] = biterr(data, demodData);
   end
 
-  fig1 = figure(1);
+  figure(1);
   clf;
 
   %% Plot simulated results
   semilogy(EbN0_db, ber, 'r', 'LineWidth', 2);
   hold on;
 
-  %% Plot theoretical curve
-  %% BPSK: bit error when noise Nr > sqrt(Eb)
-  %%   Pr(Nr > sqrt(Eb))
-  %% = Pr(Z > sqrt(Eb) / sqrt(N0/2))
-  %%
-  %% QPSK = 2 BPSKs, one real and one imaginary, each with one bit
-  %% so BER is the same as BPSK (assuming Gray code)
+  theoreticalPSK(EbN0_db, M, 'b', 'LineWidth', 1);
+
   if M == 2 || M == 4
-    ber_th = qfunc(sqrt(2 * EbN0));
-    semilogy(EbN0_db, ber_th, 'b', 'LineWidth', 1);
     legend('Simulated', 'Theoretical');
   else
-    %% Upper bound: R. Venkataramanan, Lent 2018, 3F4 Examples Paper 2
-    %%              (Question 5), CUED.
-    %% Approximation: J.G. Proakis and M. Salehi, 2000, Contemporary
-    %%                Communication Systems using MATLAB (Equations
-    %%                7.3.18 and 7.3.19), Brooks/Cole.
-    ber_ub = 2 * qfunc(sqrt(EbN0 * log2(M)) * sin(pi / M));
-    ber_ap = 2 * qfunc(sqrt(EbN0 * log2(M) * 2) * sin(pi / M)) / log2(M);
-    semilogy(EbN0_db, ber_ub, 'b', 'LineWidth', 1);
-    semilogy(EbN0_db, ber_ap, 'g', 'LineWidth', 1);
-    legend('Simulated', 'Upper bound', 'Approximation');
+    legend('Simulated', 'Approximation');
   end
 
   title(strcat(num2str(M), '-PSK with Gray code'));
@@ -72,6 +52,6 @@ function discretePSK_BER_SNR(M, numBits)
   ylabel('BER');
 
   formatFigure;
-  saveas(gcf, strcat('BER_SNR_', num2str(M), 'PSK_', num2str(numBits), ...
-                     '.svg'));
+  %saveas(gcf, strcat('BER_SNR_', num2str(M), 'PSK_', num2str(numSymbs), ...
+  %                   '.svg'));
 end