AWGN.rar_AWGN_QPSK_QPSK 误码率

function[p]=cm_bpske(snr_in_db) % [p]=cm_bpske(snr_in_db) % cm_bpske finds the probability of error for the given value of snr_in_db N=5000; E=1; %energy per symbol snr=10^(snr_in_db/10); %signal to noise ratio sgma=E/sqrt(snr*2); %noise variance %generation of data source for i=1:N temp=rand; if(temp<0.5) dsource(i)=0; else dsource(i)=1; end end %detection and the probability of errror calculation numofbiterror=0; for i=1:N %received signal at the detector ,for the ith symbol is: if (dsource(i)==0) r0=E+gngauss(sgma); r1=gngauss(sgma); else r1=E+gngauss(sgma); r0=gngauss(sgma); end % the detector is: if(r0>r1) decis=0; else decis=1; end %increment the error counter,if the decision is not correct if (decis~=dsource(i)) numofbiterror=numofbiterror+1; end end p=numofbiterror/N;