Getting Started

Setting Parameters in the Phase Noise Model

To set parameters in the model, do the following:

1. Select Simulation parameters in the Simulation menu and set Stop time to inf.
2. Double-click the AWGN Channel block and set Es/No to EbNodB+10*log10(8) in the block's mask. The variable EbNodB represents bit energy to noise ratio. The term 10*log10(8) converts EsNodB to Es/No, which is the symbol energy to noise ratio. The term 8 is present because there are eight bits per channel symbol in 256-QAM.
3. Double-click the Phase Noise block and set Phase noise level (dBc/Hz) to -66.
4. Double-click the Error Rate Calculation block and make the following changes to the default parameters in the block's mask:
• Check the box next to Stop simulation.
• Type 100 in the Target number of errors field.
• Set Maximum number of symbols to 10^5.
5. Double-click the Signal To Workspace block and make the following changes to the default parameters in the block's mask:
• Set Variable name to phase_BER.
• Set Limit data points to last to 1.
6. Type the following command at the MATLAB prompt.

• EbNoVec=20:.2:21;
  

This creates the vector

• EbNoVec =
  20.0000   20.2000   20.4000   20.6000   20.8000   21.0000
  

You can now run six simulations, with Es/No parameter values given by these vector entries plus 10 log(8). The following script runs the simulations in a loop and stores the results in a matrix called BER_Vec. The simulations might take several minutes to run.

• BER_Vec=[];
  for n=1:length(EbNoVec);
      EbNodB=EbNoVec(n);
      sim('phasenoise_sim');
      BER_Vec(n,:)=phase_BER;
  end;
  

When the simulations have ended and the prompt reappears, type the following at the MATLAB prompt.

• format short e
  BER_Vec
  

This displays the results in a matrix. Each row is the output of the Error Calculation Block for a single simulation. Notice that the first column, which gives the error rates for the six simulations, decreases. This is because the noise level decreases as EbNodB increases. The last column gives the number of symbols processed in each simulation.

Running Multiple Simulations

Plotting the Results of Multiple Simulations