16QAM、64QAM、256QAM调制解调、星座图及误码率仿真

clc clear all close all m=4; M =2^m; %M进制 SNRin=-10:1:20; linSNRin=10.^(SNRin/10); x = randi(M,5000,1)-1;%信源 y=modulate(modem.qammod(M),x); %调制 modem.qammod(M)确定调制方式 rt=zeros(1,31); e1=mean(abs(y).^2); e2=e1/m; N0=e2./linSNRin; for i=1:length(SNRin) z=zeros(1,100); z1=0; for n=1:100 %蒙特卡罗仿真 noisy=sqrt(N0(i)/2)*(randn(1,5000)+j*randn(1,5000)); ynoisy=y+noisy'; z2=demodulate(modem.qamdemod(M),ynoisy); [num,z(n)]= biterr(x,z2); z1=z(n)+z1; end rt(i)=z1/100; end semilogy(SNRin,rt,'linewidth',2);%也可以用plot(semilogy画图时纵坐标取对数了) axis([-10 13 0.000001 1]); title('误比特率曲线'); %xlabel('信噪比'); ylabel('误比特率'); grid on; hold on; m=6; M =2^m; %M进制 SNRin=-10:1:20; linSNRin=10.^(SNRin/10); x = randi(M,5000,1)-1;%信源 y=modulate(modem.qammod(M),x); %调制 modem.qammod(M)确定调制方式 rt=zeros(1,31); e1=mean(abs(y).^2); e2=e1/m; N0=e2./linSNRin; for i=1:length(SNRin) z=zeros(1,100); z1=0; for n=1:100 %蒙特卡罗仿真 noisy=sqrt(N0(i)/2)*(randn(1,5000)+j*randn(1,5000)); ynoisy=y+noisy'; %ynoisy = awgn(y,SNRin(i)); z2=demodulate(modem.qamdemod(M),ynoisy); [num,z(n)]= biterr(x,z2); z1=z(n)+z1; end rt(i)=z1/100; end semilogy(SNRin,rt,'r *-','linewidth',2);%也可以用plot(semilogy画图时纵坐标取对数了) axis([-10 13 0.000001 1]); title('误比特率曲线'); %xlabel('信噪比'); ylabel('误比特率'); grid on; m=8; M =2^m; %M进制 SNRin=-10:1:20; linSNRin=10.^(SNRin/10); x = randi(M,5000,1)-1;%信源 y=modulate(modem.qammod(M),x); %调制 modem.qammod(M)确定调制方式 rt=zeros(1,31); e1=mean(abs(y).^2); e2=e1/m; N0=e2./linSNRin; for i=1:length(SNRin) z=zeros(1,100); z1=0; for n=1:100 %蒙特卡罗仿真 noisy=sqrt(N0(i)/2)*(randn(1,5000)+j*randn(1,5000)); ynoisy=y+noisy'; %ynoisy = awgn(y,SNRin(i)); z2=demodulate(modem.qamdemod(M),ynoisy); [num,z(n)]= biterr(x,z2); z1=z(n)+z1; end rt(i)=z1/100; end semilogy(SNRin,rt,'g +-','linewidth',2);%也可以用plot(semilogy画图时纵坐标取对数了) axis([-10 13 0.000001 1]); title('误比特率曲线'); xlabel('Eb/N0(dB)'); ylabel('误比特率'); grid on; legend('16QAM','64QAM','256QAM',3);