【matlab编程代做】OFDM.doc

clc;clear;%参数初始化i=sqrt(-1);awgn=0; % 定义高斯信道se=0; % 估计技术nse=64; % OFDM载波个数ng=16; % 循环前缀长度SNR=0 5 10 15 20 25 30 35 40; % 信噪比mt=2; % 发送天线mr=2; % 接收天线pilot=1:nse/ng:nse; % 子带载波 ds=5; % 信道延迟number=200;%= N=50; fm=100; B=20e3; fd=(rand(1,N)-0.5)*2*fm; theta=randn(1,N)*2*pi; c=randn(1,N); c=c/sum(c.2); t=0:fm/B:10000*fm/B; T_c=zeros(size(t); T_s=zeros(size(t); for k=1:N T_c=c(k)*cos(2*pi*fd(k)*t+theta(k)+T_c; T_s=c(k)*sin(2*pi*fd(k)*t+theta(k)+T_s; end r=ones(mt*mr,1)*(T_c.2+T_s.2).0.5; index=floor(rand(mt*mr,ds)*5000+1);MEE1=zeros(1,length(SNR);MEE2=zeros(1,length(SNR);for snrl=1:length(SNR) snrl estimation_error1=zeros(mt*mr,nse); estimation_error2=zeros(mt*mr,nse); R1=besselj(0,2*pi*fm*(nse+ng)/B); sigma2=10(-SNR(snrl)/10); aa=(1-R12)/(1-R12+sigma2); bb=sigma2*R1/(1-R12+sigma2); for iteration=1:number if awgn=1 h=ones(mt*mr,1); else phi=rand*2*pi; h=r(index+iteration)*exp(j*phi); h=h.*(ones(mt*mr,1)*(exp(-0.5).1:ds); h=h./(sqrt(sum(abs(h).2,2)*ones(1,ds); end % 信道长度 CL=size(h,2); data_time=zeros(mt,nse+ng); data_qam=zeros(mt,nse); data_out=zeros(mr,nse); output=zeros(mr,nse); for tx=1:mt data_b=0*round(rand(4,nse); data_qam(tx,:)=j*(2*(mod(data_b(1,:)+data_b(2,:),2)+2*data_b(1,:)-3)+2*(mod(data_b(3,:)+data_b(4,:),2)+2*data_b(3,:)-3; for loop=1:mt data_qam(tx,pilot+loop-1)=(1+j)*(loop=tx); end data_time_temp=ifft(data_qam(tx,:); data_time(tx,:)=data_time_temp(end-ng+1:end) data_time_temp; end for rx=1:mr for tx=1:mt output_temp=conv(data_time(tx,:),h(rx-1)*mt+tx,:); output(rx,:)=output_temp(ng+1:ng+nse)+output(rx,:); end np=(sum(abs(output(rx,:).2)/length(output(rx,:)*sigma2; noise=(randn(size(output(rx,:)+i*randn(size(output(rx,:)*sqrt(np); output(rx,:)=output(rx,:)+noise; data_out(rx,:)=fft(output(rx,:); end %信道估计 H_act=zeros(mt*mr,nse); H_est1=zeros(mt*mr,nse); H_est2=zeros(mt*mr,nse); i=1; for tx=1:mt for rx=1:mr H_est_temp=data_out(rx,pilot+tx-1)./data_qam(tx,pilot+tx-1); h_time=ifft(H_est_temp); h_time=h_time zeros(1,nse-length(h_time); H_est1(rx-1)*mt+tx,:)=fft(h_time); H_est2(rx-1)*mt+tx,:)=(aa*abs(H_est1(rx-1)*mt+tx,:)+bb*abs(H_est2(rx-1)*mt+tx,:). .*H_est1(rx-1)*mt+tx,:)./abs(H_est1(rx-1)*mt+tx,:); if (tx1) H_est1(rx-1)*mt+tx,:)=H_est1(rx-1)*mt+tx,nse-tx+2:nse) H_est1(rx-1)*mt+tx,1:nse-tx+1); H_est2(rx-1)*mt+tx,:)=H_est2(rx-1)*mt+tx,nse-tx+2:nse) H_est2(rx-1)*mt+tx,1:nse-tx+1); end H_act(rx-1)*mt+tx,:)=fft(h(rx-1)*mt+tx,:) zeros(1,nse-CL); error1=(abs(H_act(rx-1)*mt+tx,:)-H_est1(rx-1)*mt+tx,:).2); error2=(abs(H_act(rx-1)*mt+tx,:)-H_est2(rx-1)*mt+tx,:).2); estimation_error1(rx-1)*mt+tx,:)=estimation_error1(rx-1)*mt+tx,:)+error1; estimation_error2(rx-1)*mt+tx,:)=estimation_error2(rx-1)*mt+tx,:)+error2; end end end estimation_error1=estimation_error1/number; estimation_error2=estimation_error2/number; MEE1(snrl)=sum(sum(estimation_error1)/(mt*mr*nse); MEE2(snrl)=sum(sum(estimation_error2)/(mt*mr*nse);endplot(SNR,10*log10(MEE1); hold on;plot(SNR,10*log10(MEE2),r);error1=(abs(H_act-H_est1).2)./(abs(H_act).2);error2=(abs(H_act-H_est2).2)./(abs(H_act).2);fig=4;i=1;figure(1);subplot(fig,1,i),plot(0:length(H_act)-1,abs(H_act); i=i+1;subplot(fig,1,i),plot(0:length(H_est1)-1,abs(H_est1); i=i+1;subplot(fig,1,i),plot(0:length(H_est2)-1,abs(H_est2); i=i+1;subplot(fig,1,i),plot(0:length(error1)-1,error1); i=i+1;IFFT_bin_length=128;carrier_count=100;biT_s_per_symbol=2;symbols_per_carrier=12;LI=7 ; Np=ceil(carrier_count/LI)+1;N_number=carrier_count*symbols_per_carrier*biT_s_per_symbol;carriers=1:carrier_count+Np;GI=8; N_snr=40; % 每比特信噪比snr=8; %信噪比间隔 X=zeros(1,N_number) ;XX=zeros(1,N_number) ;dif_bit=zeros(1,N_number) ;dif_bit1=zeros(1,N_number);dif_bit2=zeros(1,N_number);dif_bit3=zeros(1,N_number);X=randint(1,N_number) ;s=(X.*2-1)/sqrt(2) ;sreal=s(1:2:N_number) ;simage=s(2:2:N_number) ;%=X1=sreal+j.*simage;train_sym=randint(1,2*symbols_per_carrier);t=(train_sym.*2-1)/sqrt(2);treal=t(1:2:2*symbols_per_carrier);timage=t(2:2:2*symbols_per_carrier);training_symbols1=treal+j.*timage;training_symbols2=training_symbols1.;training_symbols=repmat(training_symbols2,1,Np);pilot=1:LI+1:carrier_count+Np;if length(pilot)=Np pilot=pilot,carrier_count+Np;end%串并转换X2=reshape(X1,carrier_count,symbols_per_carrier).;%插入导频signal=1:carrier_count+Np;signal(pilot)=;X3(:,pilot)=training_symbols;X3(:,signal)=X2;IFFT_modulation=zeros(symbols_per_carrier,IFFT_bin_length);IFFT_modulation(:,carriers)=X3;X4=ifft(IFFT_modulation,IFFT_bin_length,2);%加保护间隔（循环前缀）for k=1:symbols_per_carrier; for i=1:IFFT_bin_length; X6(k,i+GI)=X4(k,i); end for i=1:GI; X6(k,i)=X4(k,i+IFFT_bin_length-GI); endend%并串转换X7=reshape(X6.,1,symbols_per_carrier*(IFFT_bin_length+GI);%信道模型:带多普勒频移的瑞利衰落信道fd=100; %多普勒频移r=6; %多径数a=0.123 0.3 0.4 0.5 0.7 0.8; %多径的幅度d=2 3 4 5 9 13; %各径的延迟T=1; %系统采样周期th=90 0 72 144 216 288*pi./180;%相移h=zeros(1,carrier_count);hh=; for k=1:r h1=a(k)*exp(j*(2*pi*T*fd*d(k)/carrier_count); hh=hh,h1; end h(d+1)=hh;channel1=zeros(size(X7);channel1(1+d(1):length(X7)=hh(1)*X7(1:length(X7)-d(1);channel2=zeros(size(X7);channel2(1+d(2):length(X7)=hh(2)*X7(1:length(X7)-d(2);channel3=zeros(size(X7);channel3(1+d(3):length(X7)=hh(3)*X7(1:length(X7)-d(3);channel4=zeros(size(X7);channel4(1+d(4):length(X7)=hh(4)*X7(1:length(X7)-d(4);channel5=zeros(size(X7);channel5(1+d(5):length(X7)=hh(5)*X7(1:length(X7)-d(5);channel6=zeros(size(X7);channel6(1+d(6):length(X7)=hh(6)*X7(1:length(X7)-d(6);Tx_data=X7+channel1+channel2+channel3+channel4;%加高斯白噪声Error_ber=;%误比特率Error_ber1=;Error_ber2=;%误比特率Error_ber3=;for snr_db=0:snr:N_snr code_power=0; code_power=norm(Tx_data)2/(length(Tx_data); %信号的符号功率 bit_power=code_power/biT_s_per_symbol; %比特功率 noise_power=10*log10(bit_power/(10(snr_db/10);%噪声功率 noise=wgn(1,length(Tx_data),noise_power,complex);%产生GAUSS白噪声信号 Y7=Tx_data+noise; %串并变换 Y6=reshape(Y7,IFFT_bin_length+GI,symbols_per_carrier).; %去保护间隔 for k=1:symbols_per_carrier; for i=1:IFFT_bin_length; Y5(k,i)=Y6(k,i+GI); end end Y4=fft(Y5,IFFT_bin_length,2); Y3=Y4(:,carriers); %LS信道估计 H=; Y2=Y3(:,signal); Rx_training_symbols=Y3(:,pilot); Rx_training_symbols0=reshape(Rx_training_symbols,symbols_per_carrier*Np,1); training_symbol0=reshape(training_symbols,1,symbols_per_carrier*Np); training_symbol1=diag(training_symbol0); training_symbol2=inv(training_symbol1); Hls=training_symbol2*Rx_training_symbols0; Hls1=reshape(Hls,symbols_per_carrier,Np); HLs=; HLs1=; if ceil(carrier_count/LI)=carrier_count/LI for k=1:Np-1 HLs2=; for t=1:LI HLs1(:,1)=(Hls1(:,k+1)-Hls1(:,k)*(t-1)./LI+Hls1(:,k); HLs2=HLs2,HLs1; end HLs=HLs,HLs2; endelse for k=1:Np-2 HLs2=; for t=1:LI HLs1(:,1)=(Hls1(:,k+1)-Hls1(:,k)*(t-1)./LI+Hls1(:,k); HLs2=HLs2,HLs1; end HLs=HLs,HLs2; end HLs3=; for t=1:mod(carrier_count,LI) HLs1(:,1)=(Hls1(:,Np)-Hls1(:,Np-1)*(t-1)./LI+Hls1(:,Np-1); HLs3=HLs3,HLs1; end; HLs=HLs,HLs3; end Y1=Y2./HLs; %并串变换 YY=reshape(Y2.,1,N_number/biT_s_per_symbol); YY1=reshape(Y1.,1,N_number/biT_s_per_symbol);%QPSK解调 y_real=sign(real(YY); y_image=sign(imag(YY); y_re=y_real./sqrt(2); y_im=y_image./sqrt(2); y_real1=sign(real(YY1); y_image1=sign(imag(YY1); y_re1=y_real1./sqrt(2); y_im1=y_image