MATLAB仿真16QAM调制解调

clc clear ; close all; M=16;%mqam的进制数 mqam_count =400; snr=13; %信噪比 %-------------------------------------& bit_per_symbol=log2(M); % 每个符号占的比特等于4 bit_length = mqam_count*bit_per_symbol; %所有符号加起来占的比特数量= 4x400 bit_signal = round(rand(1,bit_length))'; %生成一个1600x1的包含 1，0 的矩阵 figure(1);plot(bit_signal); axis([0 100 -1 2]); %这里是限定横轴是从0-100， 纵轴是从-1到2 title('发射码元') xlabel('第几bit'); ylabel('二进制值'); bit_moded1 = qammod(bit_signal,M,'InputType','bit'); %输出使用正交幅度调制消息信号X的复包络。 %M是字母表大小，必须是2的整数幂，表示调制阶数。消息信号X必须由0到M-1之间的整数组成。X可以是标量、矢量、矩阵或三维数组。 figure(2) scatter(real(bit_moded1),imag(bit_moded1),'*g'); title('调制后的星座图'); %-------------------------------------% signal_time_C_W_R=awgn(real(bit_moded1),snr); %在信号中加入高斯白噪声 signal_time_C_W_i=awgn(imag(bit_moded1),snr); signal_time_C_W=complex(signal_time_C_W_R,signal_time_C_W_i); figure(3) scatter(1.5*real(signal_time_C_W),1.5*imag(signal_time_C_W),'.g'); title('接收的星座图'); %-------------------------------------% eyediagram(bit_moded1,2) title('眼图'); eyediagram(signal_time_C_W,2) title('眼图'); %-------------------------------------% snr_qq=0; qq=zeros(150,1); for i=0:149 bit_moded_qq = qammod(bit_signal,M,'InputType','bit'); snr_qq=snr_qq+0.1; signal_time_C_W_R=awgn(real(bit_moded_qq),snr_qq); signal_time_C_W_i=awgn(imag(bit_moded_qq),snr_qq); signal_time_C_W=complex(signal_time_C_W_R,signal_time_C_W_i); bit_demod_sig=qamdemod(signal_time_C_W,M,'OutputType','bit'); error_bit = sum(bit_demod_sig~=bit_signal); error_rate = error_bit/length(bit_signal); qq(i+1)=error_rate; end figure;plot(bit_demod_sig); axis([0 100 -1 2]); %这里是限定横轴是从0-100， 纵轴是从-1到2 title('接收') xlabel('第几bit'); ylabel('二进制值'); %功率谱 Ns=32; %每码元的采样点数 Ts=2; %ms T=M*Ts; dt=Ts/Ns; t=[-T/2:dt:T/2-dt]; [f1,tmp1]=t2f(t,bit_signal); [f2,tmp2]=t2f(t,bit_demod_sig); Tmp1=10*log10(tmp1); Tmp2=10*log10(tmp2); Tmp1=abs(Tmp1).^2; Tmp2=abs(Tmp2).^2; figure subplot(2,1,1) plot(f1,Tmp1) title('发射时功率谱'); % axis([-2,2,-50,20]) subplot(2,1,2) plot(f2,Tmp2) title('接收时功率谱'); figure plot(0:0.1:14.9,qq) title('误码率曲线16qam'); %-----------------------------------% fs = 1000; sps = 32; txfilter = comm.RaisedCosineTransmitFilter('OutputSamplesPerSymbol',sps); ed = comm.EyeDiagram('SampleRate',fs*sps,'SamplesPerSymbol',sps); txSig = txfilter(signal_time_C_W); ed(txSig)