MIMO-OFDM无线通信技术及MATLAB实现 CFO估计技术.zip

clear, clf CFO = 0.15; %频偏 Nfft=128; %FFT的点数 Nbps=2; %调制阶数 M=2^Nbps; Es=1; A=sqrt(3/2/(M-1)*Es); %信号幅度 N=Nfft; Ng=Nfft/4; %循环前缀或保护间隔长度 Nofdm=Nfft+Ng; %一个OFDM符号长度 Nsym=3; h=complex(randn,randn)/sqrt(2);%信道冲击响应 %% Transmit signal x=[]; for m=1:Nsym msgint=randi([0,M-1],N); if i<=2 Xp = add_pilot(zeros(1,Nfft),Nfft,4); Xf=Xp; else mod_object = modem.qammod('M',M, 'SymbolOrder','gray'); Xf = A*modulate(mod_object,msgint); end xt = ifft(Xf,Nfft); x_sym = add_CP(xt,Ng); x= [x x_sym]; end y=x; sig_pow= y*y'/length(y); SNRdBs= 0:3:30; MaxIter = 100; for i=1:length(SNRdBs) SNRdB = SNRdBs(i); MSE_CFO_CP = 0; MSE_CFO_Moose = 0; MSE_CFO_Classen = 0; rand('seed',1); randn('seed',1); y_CFO= add_CFO(y,CFO,Nfft); for iter=1:MaxIter y_aw = awgn(y_CFO,SNRdB,'measured'); Est_CFO_CP = CFO_CP(y_aw,Nfft,Ng); MSE_CFO_CP = MSE_CFO_CP + (Est_CFO_CP-CFO)^2; Est_CFO_Moose = CFO_Moose(y_aw,Nfft); MSE_CFO_Moose = MSE_CFO_Moose + (Est_CFO_Moose-CFO)^2; Est_CFO_Classen = CFO_Classen(y_aw,Nfft,Ng,Xp); MSE_CFO_Classen = MSE_CFO_Classen + (Est_CFO_Classen-CFO)^2; end MSE_CP(i)=MSE_CFO_CP/MaxIter; MSE_Moose(i)=MSE_CFO_Moose/MaxIter; MSE_Classen(i)=MSE_CFO_Classen/MaxIter; end semilogy(SNRdBs, MSE_CP,'-+') grid on hold on semilogy(SNRdBs, MSE_Moose,'-x') semilogy(SNRdBs, MSE_Classen,'-*') xlabel('SNR[dB]'), ylabel('MSE'); title('CFO Estimation'); legend('CP-based technique','Moose (Preamble-based)','Classen (Pilot-based)');