QPSK调制解调代码.rar

clear all; close all; clc; SNR_dB=0:10; err_ber=zeros(1,length(SNR_dB)); BER_R = [0.07865,0.05628,0.03751,0.02288,0.0125,0.005954,0.002388,0.0007727,0.0001909,3.363e-05,3.872e-06]; for j=1:length(SNR_dB) error_bit=0; baseband_out=round(rand(500000,2)); [m,n]=size(baseband_out); total_bit_num=m*n; %qpsk调制 loc = find(baseband_out==0); baseband_out(loc)=-1; map_out = baseband_out(:,1)+1i*baseband_out(:,2); %加噪声 receive_symbol=awgn(map_out,SNR_dB(j)); %qpsk解调 [m,n]=size(receive_symbol); receive_bit_sig=zeros(m,2*n); receive_bit_sig(:,1)=real(receive_symbol); receive_bit_sig(:,2)=imag(receive_symbol); d1=(receive_bit_sig(:,1)-1).^2+(receive_bit_sig(:,2)-1).^2; d2=(receive_bit_sig(:,1)-(-1)).^2+(receive_bit_sig(:,2)-1).^2; d3=(receive_bit_sig(:,1)-(-1)).^2+(receive_bit_sig(:,2)-(-1)).^2; d4=(receive_bit_sig(:,1)-1).^2+(receive_bit_sig(:,2)-(-1)).^2; for k=1:length(d1) shuzu=[d1(k) d2(k) d3(k) d4(k)]; [x, y]=find(shuzu==min(min(shuzu))); if y==1 receive_bit_sig(k,:)=[1 1]; elseif y==2 receive_bit_sig(k,:)=[-1 1]; elseif y==3 receive_bit_sig(k,:)=[-1 -1]; elseif y==4 receive_bit_sig(k,:)=[1 -1]; end end err_num=error_count(baseband_out,receive_bit_sig); error_bit=error_bit+err_num err_ber(j)=error_bit/total_bit_num; end semilogy(SNR_dB,err_ber,'r-o') title('仅加入高斯白噪声情况下的BER') legend('仅加噪声','标准bertool') xlabel('SNR')%x轴 ylabel('BER')%y轴 grid on%打开网格 hold on%保留原来的画线 semilogy(SNR_dB,BER_R,'g-+') legend('仅加噪声','标准bertool') xlabel('SNR') ylabel('BER') grid on hold on