OFDM基本程序.zip_IFFT_modulation_OFDM信道估计_ofdm matlab_信道估计 bpsk_通信 加

% OFDM_基本程序.m %MIMO-OFDM Wireless Communications with MATLAB ㈢ Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang %2010 John Wiley & Sons (Asia) Pte Ltd clear all clc NgType=1; % NgType=1/2 for cyclic prefix/zero padding if NgType==1, nt='CP'; elseif NgType==2, nt='ZP'; end Ch=0; % Ch=0/1 for AWGN/multipath channel if Ch==0, chType='AWGN'; Target_neb=100; else chType='CH'; Target_neb=500; end figure(Ch+1), clf PowerdB=[0 -8 -17 -21 -25]; % Channel tap power profile 'dB' Delay=[0 3 5 6 8]; % Channel delay 'sample' Power=10.^(PowerdB/10); % Channel tap power profile 'linear scale' Ntap=length(PowerdB); % Chanel tap number Lch=Delay(end)+1; %Channel length Nbps=4; M=2^Nbps; % Modulation order=2/4/6 for QPSK/16QAM/64QAM Nfft=64; % FFT size Ng=16; %Nfft/4; % Ng=0: Guard interval length Ng=Nfft/4; Nsym=Nfft+Ng; % Symbol duration Nvc=Nfft/4; % Nvc=0: no virtual carrier Nused=Nfft-Nvc; EbN0=0:5:30; % EbN0 N_iter=1e3; % Number of iterations for each EbN0 Nframe=3; % Number of symbols per frame sigPow=0; % Signal power initialization file_name=['OFDM_BER_' chType '_' nt '_' 'GL' num2str(Ng) '.dat']; fid=fopen(file_name, 'w+'); norms=[1 sqrt(2) 0 sqrt(10) 0 sqrt(42)]; % BPSK 4-QAM 16-QAM i=0; while(i<=length(EbN0)) %for i=0:length(EbN0) % randn('state',0); rand('state',0); Ber2=ber(); % BER initialization Neb=0; Ntb=0; % Initialize the number of error/total bits for m=1:N_iter % Tx______________________________________________________________ % X= randint(1,Nused*Nframe,M); % bit: integer vector X= randi(1,Nused*Nframe,M); % bit: integer vector Xmod= qammod(X,M,0,'gray')/norms(Nbps); if NgType~=2, x_GI=zeros(1,Nframe*Nsym); elseif NgType==2, x_GI= zeros(1,Nframe*Nsym+Ng); % Extend an OFDM symbol by Ng zeros end kk1=[1:Nused/2]; kk2=[Nused/2+1:Nused]; kk3=1:Nfft; kk4=1:Nsym; for k=1:Nframe if Nvc~=0, X_shift= [0 Xmod(kk2) zeros(1,Nvc-1) Xmod(kk1)]; else X_shift= [Xmod(kk2) Xmod(kk1)]; end x= ifft(X_shift); x_GI(kk4)= guard_interval(Ng,Nfft,NgType,x); kk1=kk1+Nused; kk2= kk2+Nused; kk3=kk3+Nfft; kk4=kk4+Nsym; end if Ch==0, y= x_GI; % No channel else % Multipath fading channel %channel=(randn(1,Ntap)+j*randn(1,Ntap)).*sqrt(Power/2); channel=(randn(1,Ntap)+li*randn(1,Ntap)).*sqrt(Power/2); h=zeros(1,Lch); h(Delay+1)=channel; % cir: channel impulse response y = conv(x_GI,h); %卷积和多项式乘法 end if i==0 % Only to measure the signal power for adding AWGN noise y1=y(1:Nframe*Nsym); sigPow = sigPow + y1*y1'; continue; end % Add AWGN noise________________________________________________ snr = EbN0(i)+10*log10(Nbps*(Nused/Nfft)); % SNR vs. Eb/N0 noise_mag = sqrt((10.^(-snr/10))*sigPow/2); %y_GI = y + noise_mag*(randn(size(y))+j*randn(size(y))); y_GI = y + noise_mag*(randn(size(y))+1i*randn(size(y))); % Rx_____________________________________________________________ kk1=(NgType==2)*Ng+1:Nsym; kk2=1:Nfft; kk3=1:Nused; kk4=Nused/2+Nvc+1:Nfft; kk5=(Nvc~=0)+[1:Nused/2]; if Ch==1 H= fft([h zeros(1,Nfft-Lch)]); % Channel frequency response H_shift(kk3)= [H(kk4) H(kk5)]; end for k=1:Nframe Y(kk2)= fft(remove_GI(Ng,Nsym,NgType,y_GI(kk1))); Y_shift=[Y(kk4) Y(kk5)]; if Ch==0, Xmod_r(kk3) = Y_shift; else Xmod_r(kk3)= Y_shift./H_shift; % Equalizer - channel compensation end kk1=kk1+Nsym; kk2=kk2+Nfft; kk3=kk3+Nused; kk4=kk4+Nfft; kk5=kk5+Nfft; end X_r=qamdemod(Xmod_r*norms(Nbps),M,0,'gray'); size(Neb); size(de2bi(X_r,Nbps)); Neb=Neb+sum(sum(de2bi(X_r,Nbps))); %~=de2bi(X,Nbps))); %Matrix dimensions must agree. Ntb=Ntb+Nused*Nframe*Nbps; %[Ber,Neb,Ntb]=ber(bit_Rx,bit,Nbps); if Neb>Target_neb, break; end end if i==0 sigPow= sigPow/Nsym/Nframe/N_iter; fprintf('Signal power= %11.3e\n', sigPow); fprintf(fid,'%%Signal power= %11.3e\n%%EbN0[dB] BER\n', sigPow); else Ber = Neb/Ntb; %EbN0 显示部分 % [EbN0(i),Neb,Ntb,Ber] %fprintf('EbN0=%3d[dB], BER= %4d / %8d =%11.3e \n', EbN0(i), Neb,Ntb,Ber) fprintf('EbN0=%3d[dB], %4d %8d %11.3e \n', EbN0(i), Neb,Ntb,Ber) fprintf(fid, '%d\t%11.3e\n', EbN0(i), Ber); if Ber<1e-6, break; end end i=i+1; end if (fid~=0), fclose(fid); end disp('Simulation is finished'); plot_ber(file_name,Nbps); function plot_ber(file_name,Nbps) %MIMO-OFDM Wireless Communications with MATLAB ㈢ Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang %2010 John Wiley & Sons (Asia) Pte Ltd EbN0dB=[0:1:30]; M=2^Nbps; ber_AWGN = ber_QAM(EbN0dB,M,'AWGN'); ber_Rayleigh = ber_QAM(EbN0dB,M,'Rayleigh'); semilogy(EbN0dB,ber_AWGN,'r:'), hold on, semilogy(EbN0dB,ber_Rayleigh,'r-') a= load(file_name); semilogy(a(:,1),a(:,2),'b--s'); grid on legend('AWGN analytic','Rayleigh fading analytic', 'Simulation'); xlabel('EbN0[dB]'), ylabel('BER'); axis([a(1,1) a(end,1) 1e-5 1]) function y=Q(x) % co-error function: 1/sqrt(2*pi) * int_x^inf exp(-t^2/2) dt. y=erfc(x/sqrt(2))/2; function y=remove_GI(Ng,Lsym,NgType,ofdmSym) %MIMO-OFDM Wireless Communications with MATLAB ㈢ Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang %2010 John Wiley & Sons (Asia) Pte Ltd if Ng~=0 if NgType==1 % cyclic prefix y=ofdmSym(Ng+1:Lsym); elseif NgType==2 % cyclic suffix y=ofdmSym(1:Lsym-Ng)+[ofdmSym(Lsym-Ng+1:Lsym) zeros(1,Lsym-2*Ng)]; end else y=ofdmSym; end function ber=ber_QAM(EbN0dB,M,AWGN_or_Rayleigh) % Find ananlytical BER of Mary QAM in AWGN or Rayleigh channel % EbN0dB=EbN0dB: Energy per bit-to-noise power[dB] for AWGN channel % =rdB: Average SNR(2*sigma Eb/N0)[dB] for Rayleigh channel % M = Modulation order (Constellation size) %MIMO-OFDM Wireless Communications with MATLAB ㈢ Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang %2010 John Wiley & Sons (Asia) Pte Ltd N= length(EbN0dB); sqM= sqrt(M); a= 2*(1-power(sqM,-1))/log2(sqM); b= 6*log2(sqM)/(M-1); if nargin<3, AWGN_or_Rayleigh='AWGN'; end if lower(AWGN_or_Rayleigh(1))=='a', ber = a*Q(sqrt(b*10.^(EbN0dB/10))); else rn= b*10.^(EbN0dB/10)/2; ber = 0.5*a*(1-sqrt(rn./(rn+1))); End function y = guard_interval(Ng,Nfft,NgType,ofdmSym) %MIMO-OFDM Wireless Communications with MATLAB ㈢ Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang %2010 John Wiley & Sons (Asia) Pte Ltd if NgType==1 y=[ofdmSym(Nfft-Ng+1:Nfft) ofdmSym(1:Nfft)]; elseif NgType==2 y=[zeros(1,Ng) ofdmSym(1:Nfft)]; end