Generating a correlated Rayleigh fading process

In this example we will generate a correlated Rayleigh fading process with a normaized Doppler frequency equal to 0.1. The normalized Doppler is defined as the multiplication of the maximum Doppler frequency by the sampling time (i.e. \(f_d = F_d T_s\)).

#include <itpp/itcomm.h>
 
using namespace itpp;
 
int main()
{
  // Declare my_channel variable as an instance of the Rayleigh_Channel
  // class
  TDL_Channel my_channel;
 
  // The normalized Doppler frequency is set to 0.1
  double norm_dopp = 0.1;
  my_channel.set_norm_doppler(norm_dopp);
 
  // Generate nrof_samples of the fading process and store them in ch_coeffs
  // matrix
  int nrof_samples = 10000;
  cmat ch_coeffs;
  my_channel.generate(nrof_samples, ch_coeffs);
 
  // Open an output file "rayleigh_test.it"
  it_file ff("rayleigh_test.it");
 
  // Save channel coefficients to the output file
  ff << Name("ch_coeffs") << ch_coeffs;
 
  // Close the output file
  ff.close();
 
  // Exit program
  return 0;
}

You can use Matlab or Octave to examine the channel fading process that is stored int the output file rayleigh_test.it. Try the followigh code to view a part of the fading process:

itload("rayleigh_test.it")
figure(1); clf;
semilogy(abs(ch_coeffs(1:200)))

Note: Make sure that the folder $PREFIX/share/itpp is included your Matlab/Octave path variable ($PREFIX is the IT++ installation prefix: /usr/local by default).