%%------------------------------------------------------------%軟件無(wú)線電課程設(shè)計(jì)%%方形、星形16QAM調(diào)制解調(diào)仿真%%%------------------------------------------------------------%%主程序clcclear%%定義參數(shù)fd=250*10^6;%碼元速率250Mfs=2500*10^6;%濾波器采樣率fc=2500*10^6;%載波頻率2.5Gf=10000*10^6;%對(duì)載波采樣data_len=200000;%數(shù)據(jù)長(zhǎng)度sym_len=data_len/4;%碼元序列長(zhǎng)度M_QAM=16;%QAM數(shù)k=log2(M_QAM);SNR=1:12;%白噪聲信噪比,%%------------------------------------------------------------bit_tx=randint(1,data_len);%產(chǎn)生隨機(jī)序列echooff;rec_qam16=QamMod(bit_tx,16);%方形16QAM調(diào)制star_qam16=SrarQamMod(bit_tx);%星形16QAM調(diào)制base_rec=base_shape(fd,fs,f,rec_qam16);%基帶成型濾波base_star=base_shape(fd,fs,f,star_qam16);%基帶成型濾波fori=1:length(SNR)%信噪比從1dB到12dB計(jì)算誤碼率SNR_=i%方形映射16QAMrf_rec_qam16=CarrierMod(fc,f,base_rec);%載波調(diào)制rf_rec_qam16_n=awgn(rf_rec_qam16,SNR(i),'measured');%加噪聲[rec_qam16_rxbase_rec_rx]=CarrierDemod(fd,fs,fc,f,rf_rec_qam16_n);%載波解調(diào)bit_rec_rx=QamDemod(rec_qam16_rx,16);%MQAM解調(diào)[num_qam16,perr_qam16_rec(i)]=biterr(bit_tx,bit_rec_rx);%誤碼率qam16_data_rec(i,:)=rec_qam16_rx;%scatterplot(rec_qam16_rx);%星形映射16QAMrf_star_qam16=CarrierMod(fc,f,base_star);%載波調(diào)制rf_star_qam16_n=awgn(rf_star_qam16,SNR(i),'measured');%加噪聲[star_qam16_rxbase_star_rx]=CarrierDemod(fd,fs,fc,f,rf_star_qam16_n);%載波解調(diào)bit_star_rx=StarQamDemod(star_qam16_rx);%MQAM解調(diào)[num_qam16,perr_qam16_star(i)]=biterr(bit_tx,bit_star_rx);%誤碼率qam16_data_star(i,:)=star_qam16_rx;%scatterplot(star_qam16_rx);end%%理論誤碼率計(jì)算SNRtheo=0:0.1:length(SNR);fori=1:length(SNRtheo)SNRdec=10.^(SNRtheo(i)/10);theo_perr_qam16(i)=(3/8)*erfc(sqrt(SNRdec*2/5));end%%基帶波形N=200;n=1:N;t=1:N*10;%發(fā)送端波形figure;stem(n,bit_tx(n));title('發(fā)送序列');%發(fā)送序列figure('Name','發(fā)送端基帶信號(hào)');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');subplot(413);plot(t,real(base_star(t)));title('星形映射-Q路');subplot(414);plot(t,imag(base_star(t)));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','接收端基帶信號(hào)');subplot(411);plot(t,real(base_rec_rx(t)));title('方形映射-Q路');subplot(412);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;%兩次根升余弦濾波延遲，定位初始信號(hào)位置%delay+1:end-delay-1R=fs/fd;delay=3*R*2;rc_Q_seq=(downsample(low_Q_rcos(delay+1:end-delay-1),R));rc_I_seq=(downsample(low_I_rcos(delay+1:end-delay-1),R));%類型轉(zhuǎn)換data_rx=rc_Q_seq+j*rc_I_seq;%--------------------------------------------------------------------------%%載波調(diào)制functiontransmit=CarrierMod(fc,f,base)%載波調(diào)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_freq_Q+high_freq_I;%------------------------------------------------------------------------------%%QAM解調(diào)程序，將MQAM碼元還原為二進(jìn)制數(shù)據(jù)%入口參數(shù)：data_QAM：QAM碼元數(shù)據(jù)%M_QAM:MQAM中M的大小%出口參數(shù)：二進(jìn)制數(shù)據(jù)比特流%------------------------------------------------------------------------functiondata_out=QamDemod(data_QAM,M_QAM)k=log2(M_QAM);%每個(gè)M進(jìn)制碼元的bit數(shù)data_len=length(data_QAM);%碼元長(zhǎng)度%-------------------------------------------------------------------%QAM信號(hào)放縮至與發(fā)送端相同比例data_temp=data_QAM(find(real(data_QAM>0)));aver=mean(real(data_temp));data_Qam_temp=data_QAM/aver*(2^(k/2-1));%------------------------------------------------------------------------%平移到第一象限data_Qam_temp2=(data_Qam_temp+(2^(k/2)-1)*(1+j))/2;%----------------------------------------------------------------------%將實(shí)部虛部分別映射為二進(jìn)制數(shù)據(jù)%實(shí)部data_real=round(real(data_Qam_temp2));%實(shí)部判決data_real(find(data_real>(2^(k/2)-1)))=2^(k/2)-1;%大于2^(k/2)-1的數(shù)據(jù)判定為2^(k/2)-1data_real(find(data_real<0))=0;%小于0的數(shù)據(jù)判為0bit_real=abs(dec2bin(data_real))-'0';%虛部data_imag=round(imag(data_Qam_temp2));%虛部判決data_imag(find(data_imag>(2^(k/2)-1)))=2^(k/2)-1;%大于2^(k/2)-1的數(shù)據(jù)判定為2^(k/2)-1data_imag(find(data_imag<0))=0;%小于0的數(shù)據(jù)判為0bit_imag=abs(dec2bin(data_imag))-'0';%------------------------------------------------------------------------%還原為二進(jìn)制比特流bit_rec=[bit_real,bit_imag]';data_out=reshape(bit_rec,1,data_len*k);%-------------------------------------------------------------------------------------------------------------%%QAM調(diào)制程序，實(shí)現(xiàn)二進(jìn)制到MQam調(diào)制%入口參數(shù)：binary：二進(jìn)制數(shù)據(jù)%M_QAM:MQAM中M的大小%返回參數(shù)：MQAM碼元%------------------------------------------------------------------------functiondata_M=QamMod(binary,M_QAM)k=log2(M_QAM);%每個(gè)M進(jìn)制碼元的bit數(shù)data_len=length(binary);%比特長(zhǎng)度binary_rec=reshape(binary,k,data_len/k)';%轉(zhuǎn)化為data_len/k行，k列，的矩陣，以便轉(zhuǎn)化為16進(jìn)制M進(jìn)制%計(jì)算實(shí)部data_str1=num2str(binary_rec(:,1:k/2));data_m_real=bin2dec(data_str1);%計(jì)算虛部data_str2=num2str(binary_rec(:,k/2+1:k));data_m_imag=bin2dec(data_str2);%實(shí)部虛部映射到MQamdata_M=((data_m_real*2-2^(k/2)+1)+j*(data_m_imag*2-2^(k/2)+1)).';%---------------------------------------------------------------------------------%%星形16QAM映射functiondata_m16=SrarQamMod(binary)%binary=randint(1,100);%產(chǎn)生隨機(jī)序列data_len=length(binary);%比特長(zhǎng)度binary_rec=reshape(binary,4,data_len/4)';%轉(zhuǎn)化為data_len/4行，4列，的矩陣，以便轉(zhuǎn)化為16進(jìn)制data_str=num2str(binary_rec);data_dec=bin2dec(data_str);data_mm16=(floor(data_dec/8)+1).*exp(j*45/180*pi*mod(data_dec,8));data_m16=