完整版16QAM星形和矩形星座图调制解调MATLAB代码

1、%软件无线电课程设计%方形、星形16QAM调制解调仿真%主程序clcclear%定义参数fd=250*10A6;fs=2500*10A6;恒=2500*10人6;f=10000*10A6;data_len=200000;sym_len=data_len/4;%码元序列长度%方形映射16QAMrf_rec_qam16=CarrierMod(fc,f,base_rec);%载波调制rf_rec_qam16_n=awgn(rf_rec_qam16,SNR(i),measured);%加噪声rec_qam16_rxbase_rec_rx=CarrierDemod(fd,fs,fc,f,rf_rec_q

2、am16_n);%载波解调bit_rec_rx=QamDemod(rec_qam16_rx,16);%MQAM解调num_qam16,perr_qam16_rec(i)=biterr(bit_tx,bit_rec_rx);%误码率qam16_data_rec(i,:)=rec_qam16_rx;%scatterplot(rec_qam16_rx);%星形映射16QAMrf_star_qam16=CarrierMod(fc,f,base_star);%载波调制rf_star_qam16_n=awgn(rf_star_qam16,SNR(i),measured);%加噪声%码元速率250M%滤波器

3、采样率%载波频率2.5G%对载波采样%数据长度M_QAM=16;%QAM数k=log2(M_QAM);SNR=1:12;%白噪声信噪比，%bit_tx=randint(1,data_len);%产生随机序列echooff;rec_qam16=QamMod(bit_tx,16);star_qam16=SrarQamMod(bit_tx);base_rec=base_shape(fd,fs,f,rec_qam16);base_star=base_shape(fd,fs,f,star_qam16);fori=1:length(SNR)SNR=i%方形16QAM调制%星形16QAM调制%基带成型滤波%

4、基带成型滤波%信噪比从1dB到12dB计算误码率star_qam16_rxbase_star_rx=CarrierDemod(fd,fs,fc,f,rf_star_qam16_n);%载波解调bit_star_rx=StarQamDemod(star_qam16_rx);%MQAM解调num_qam16,perr_qam16_star(i)=biterr(bit_tx,bit_star_rx);%误码率qam16_data_star(i,:)=star_qam16_rx;%scatterplot(star_qam16_rx);end%理论误码率计算SNRtheo=0:0.1:length(SN

5、R);fori=1:length(SNRtheo)SNRdec=10.A(SNRtheo(i)/10);theo_perr_qam16(i)=(3/8)*erfc(sqrt(SNRdec*2/5);end%基带波形N=200;n=1:N;t=1:N*10;%发送端波形figure;stem(n,bit_tx(n);title(发送序列)；发送序列figure(Name,发送端基带信号)；subplot(411);plot(t,real(base_rec(t);title(方形映射-Q路);subplot(412);plot(t,imag(base_rec(t);title(方形映射-I路);s

6、ubplot(413);plot(t,real(base_star(t);title(星形映射-Q路,);subplot(414);plot(t,imag(base_star)；title(星形映射-I路,);%接收端波形figure;subplot(211);stem(n,bit_rec_rx(n);title(方形接收序列,);subplot(212);stem(n,bit_star_rx(n);title(星形接收序列,);figure(Name,接收端基带信号)；subplot(411);plot(t,real(base_rec_rx(t);title(方形映射-Q路,);subplo

7、t(412);plot(t,imag(base_rec_rx(t);subplot(413);plot(t,real(base_star_rx(t);subplot(414);plot(t,imag(base_star_rx(t);%基带眼图N1=20000;Tn=f/fd;eye_rex=base_rec(1:N1);eyediagram(eye_rex,Tn*4,Tn);eye_star=base_star(1:N1);eyediagram(eye_star,Tn*4,Tn);title（方形映射-I路）;title（星形映射-Q路）;title（星形映射-I路）;title（方形基带眼图

8、）;title（星形基带眼图）;%接收端星座图%scatterplot(qam16_data_rec(12,:);figure(Name,方形16QAM接收端星座图);fo门=3:3:12subplot(2,2,i/3);plot(real(qam16_data_rec(i,:),imag(qam16_data_rec(i,:),.);xmax=5;axis(-xmaxxmax-xmaxxmax)title(Snr=,num2str(SNR(i),dB);endfigure(Name,星形16QAM接收端星座图);fori=3:3:12subplot(2,2,i/3);plot(real(qa

9、m16_data_star(i,:),imag(qam16_data_star(i,:),.);xmax=3;axis(-xmaxxmax-xmaxxmax)gridon;title(Snr=,num2str(SNR(i),dB);end%功率谱密度f_plot;%误码率分析%16QAM误码率曲线figure(Name,16QAM误码性能对比);%semilogy(SNRtheo,theo_perr_qam16);%holdon;semilogy(SNR,perr_qam16_rec,*);holdon;semilogy(SNR,perr_qam16_star,o);xlabel(SNRind

10、B);ylabel(PrbofErr);legend(方形16QAM,星形16QAM);title(16QAM误码性能对比,);%基带成型functionbase_info=base_shape(fd,fs,f,seq_16QAM)%平方根升余弦滤波器，滚降系数0.5,延迟3个采样点flt=rcosine(fd,fs,sqrt,0.5);%I路和Q路seq_Q=real(seq_16QAM);seq_I=imag(seq_16QAM);%增采样R=fs/fd;up_seq_Q=upsample(seq_Q,R);up_seq_I=upsample(seq_I,R);%升余弦调制rcos_Q=c

11、onv(up_seq_Q,flt);rcos_I=conv(up_seq_I,flt);%提升rcos_Q_up=interp(rcos_Q,f/fs);rcos_I_up=interp(rcos_I,f/fs);base_info=rcos_Q_up+j*rcos_I_up;%载波解调functiondata_rxbase_rx=CarrierDemod(fd,fs,fc,f,receive)%分两路乘正交高频载波rc_length=length(receive);flt=rcosine(fd,fs,sqrt,0.5);t=0:rc_length-1;rc_Q=receive.*sin(2*

12、pi*fc*t/f);rc_I=receive.*cos(2*pi*fc*t/f);%减采样后根升余弦匹配滤波，注意对齐采样点down_Q=downsample(0rc_Q,f/fs);down_I=downsample(rc_I,f/fs);low_Q_rcos=conv(down_Q,flt);low_I_rcos=conv(down_I,flt);base_rx=low_Q_rcos(1:length(low_I_rcos)+j*low_I_rcos;%两次根升余弦滤波延迟，定位初始信号位置%delay+1:end-delay-1R=fs/fd;delay=3*R*2;rc_Q_seq=

13、(downsample(low_Q_rcos(delay+1:end-delay-1),R);rc_I_seq=(downsample(low_I_rcos(delay+1:end-delay-1),R);%类型转换data_rx=rc_Q_seq+j*rc_I_seq;%载波调制functiontransmit=CarrierMod(fc,f,base)%载波调制t=0:length(base)-1;high_freq_Q=real(base).*sin(2*pi*fc*t/f);high_freq_I=imag(base).*cos(2*pi*fc*t/f);transmit=high_f

14、req_Q+high_freq_I;%QAM解调程序，将MQAM码元还原为二进制数据%人口参数：data_QAM:QAM码元数据%M_QAM:MQAM中M的大小%出口参数：二进制数据比特流%functiondata_out=QamDemod(data_QAM,M_QAM)k=log2(M_QAM);%每个M进制码元的bit数data_len=length(data_QAM);%码元长度%QAM信号放缩至与发送端相同比例data_temp=data_QAM(find(real(data_QAM0);aver=mean(real(data_temp);data_Qam_temp=data_QAM/

15、aver*(2A(k/2-1);%平移到第一象限data_Qam_temp2=(data_Qam_temp+(2A(k/2)-1)*(1+j)/2;%将实部虚部分别映射为二进制数据%实部data_real=round(real(data_Qam_temp2);%实部判决data_real(find(data_real(2A(k/2)-1)=2A(k/2)-1;%大于2A(k/2)-1的数据判定为2A(k/2)-1data_real(find(data_real(2A(k/2)-1)=2A(k/2)-1;%大于2A(k/2)-1的数据判定为2A(k/2)-1data_imag(find(data_imag2)=2;%幅度大于2的判定为2am(find(am1.5)=1;%幅度大于2的判定为2%相位判定ang=angle(qam_rev)/pi*180;%将-18