基于MATLAB的QPSK在瑞利、高斯和莱斯信道下仿真

function Pb = QPSK_Ricean_Simu(SNR_dB) % finds the BER/SER for the given snr numofbiterror = 0; E = 1; % energy per symbol i = 0; SNR = 10^(SNR_dB/10); % signal to noise ratio sgma = sqrt(E/SNR)/2; % noise variance % signal mapping s00 = [1 0]; s01 = [0 1]; s11 = [-1 0]; s10 = [0 -1]; % generation of the data source, QPSK modulation while(numofbiterror<100) i = i+1;temp = rand; if (temp<0.25) dsource1 = 0;dsource2 = 0; % with probability 1/4, output "00" elseif (temp<0.5) dsource1 = 0; dsource2 = 1; % with probability 1/4, output "01" elseif (temp<0.75) dsource1 = 1;dsource2 = 0; % with probability 1/4, output "10" else dsource1 = 1;dsource2 = 1; % with probability 1/4, output "11" end; % detection and the probability of error calculation n = sgma*randn(size(s00)); % 2 normal distributed r.v with 0, variance sgma Ric1=0.316223*randn(size(s00)); Ric2=0.8945+0.316223*randn(size(s00)); Ric=sqrt(Ric1.*Ric1+Ric2.*Ric2); if((dsource1==0)&(dsource2==0)),r = Ric.*s00+n; % go through Ricean elseif((dsource1==0)&(dsource2==1)),r = Ric.*s01+n; elseif((dsource1==1)&(dsource2==0)),r = Ric.*s10+n; else r = Ric.*s11+n; end; c00 = dot(r,s00);c01 = dot(r,s01); c10 = dot(r,s10);c11 = dot(r,s11); c_max = max([c00 c01 c10 c11]); if (c00==c_max) decis1 = 0;decis2 = 0; elseif(c01==c_max) decis1 = 0;decis2 = 1; elseif(c10==c_max) decis1 = 1;decis2 = 0; else decis1 = 1;decis2 = 1; end; if(decis1 ~= dsource1) numofbiterror = numofbiterror+1;end; if(decis2~=dsource2) numofbiterror = numofbiterror+1;end; end; Pb = numofbiterror/(2*i);