基于Matlab实现AWGN 中的 QPSK 调制.zip

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % This program is used to calculate the Bit Error Rate (BER) of QPSK in an % Additive White Gaussian Noise (AWGN) channel. The modulation and % demodulation is done at baseband. Complex numbers are used to model the % in-phase and quadrature components of a QPSK signal. The length of the % symbol sequence and range of EbNo can be varied. % clear all; %Clear all variables close all; %Close all figures l=1e6; EbNodB=0:2:10; EbNo=10.^(EbNodB/10); for n=1:length(EbNodB) si=2*(round(rand(1,l))-0.5); %In-phase symbol generation sq=2*(round(rand(1,l))-0.5); %Quadrature symbol generation s=si+j*sq; %Adding the two parallel symbol streams w=(1/sqrt(2*EbNo(n)))*(randn(1,l)+j*randn(1,l)); %Random noise generation r=s+w; %Received signal si_=sign(real(r)); %In-phase demodulation sq_=sign(imag(r)); %Quadrature demodulation ber1=(l-sum(si==si_))/l; %In-phase BER calculation ber2=(l-sum(sq==sq_))/l; %Quadrature BER calculation ber(n)=mean([ber1 ber2]); %Overall BER end semilogy(EbNodB, ber,'o-') %Plot the BER xlabel('EbNo(dB)') %Label for x-axis ylabel('BER') %Label for y-axis grid on %Turning the grid on