ip_07_06.m

根据蒙特卡罗仿真原理

% MATLAB script for Illustrative Problem 7.6.
clear;
clc;
echo on
SNRindB1=0:2:15;
SNRindB2=0:0.1:15;
M=16;
k=log2(M);
for i=1:length(SNRindB1),
  smld_symbol_err_prb(i)=cm_sm41(SNRindB1(i));	% simulated symbol error rate
  echo off;
end;
echo on ;
for i=1:length(SNRindB2),
  SNR=exp(SNRindB2(i)*log(10)/10);    	% signal-to-noise ratio
  % theoretical error rate
  theo_symbol_err_prb(i)=4*Qfunct(sqrt(3*k*SNR/(M-1)));
  theo_symbol_err_prb2(i)=(3/2)*Qfunct(sqrt((4/5)*SNR)); 
  theo_bit_err_prb2(i)=(3/4)*Qfunct(sqrt((4/5)*SNR)); 
  echo off ;
end;
echo on ;
% Plotting commands follow.
semilogy(SNRindB1,smld_symbol_err_prb,'*');
hold
semilogy(SNRindB2,theo_symbol_err_prb,'r');
semilogy(SNRindB2,theo_symbol_err_prb2);
semilogy(SNRindB2,theo_bit_err_prb2,'g');
grid
xlabel('Eb/No in dB')
ylabel('error probability')
title('16QAM通信系统的蒙特卡洛仿真')
legend('仿真符号误码率','理论符号误码率的上界','理论符号误码率','理论比特误码率')
% gtext('（注：“*”仿真符号误码率；“r—”理论符号误码率的上界；“-”理论符号误码率；“g”理论比特误码率）')