OFDM.rar_OFSMI_激光仿真_激光自混合_自混合_自混合干涉

%%%%%%%%%%% Developed for 16 QAM %%%%%%%%%%%%%% clear all close all t0=clock; %%%%%%% INPUT PARAMETERS %%%%%%%%%%% %%%%% N=, Number of FFT Points N=1024; %%%%% M=, Number of OFDM Sub Carriers M=512; %%%%% L=, Number of Symbols L=10; MMMa=64;%%%% Modulation Method %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% QPSK 16QAM MMM1a=log2(MMMa); %%%%% Tg=, Gurd Interval Ratio %%%%%%%% Tg=0.1; W=10;%%% Bandwidth(MHz) DFF=W/M; %%%%%% ts=, Effective Sumbol Duration (Micro Sec) %%%%%%% ts=M/W; %%%%%% D=, Gurd Interval Duration (Micro Sec) %%%%%%% D=ts*Tg; %%%%%% Ts=, Symbol Duration (Micro Sec) %%%%%%%%%% Ts=ts+D; st1=ts/N; %%%%%%% Ng=, Number of Samples for Gurd Interval %%%%%%% Ng=round(D/(ts/N)); %%%%%%% Nt=, Number of Samples for a Symbol %%%%%%% Nt=(N+Ng); %%%%%%% NNt=, Number of Samples for a Flame %%%%%% NNt=Nt*L; %%%%%%%%% Sampling frequency (usec) %%%%%%%%%% tbw=1/st1; %%%%%%% tsw=, Total Allocated Signal Bandwidth (MHz) %%%%%%% tsw=(1/ts*M);%%%% W bandwidth ddf=tbw/NNt; %%%% Frequency resolution %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% dt=0.1;%%%%%% delay spread ds=st1;%%%%%% delay spacing NP=10; %%%%%% number of delay path %%% Power Delay profile with Exponential decay constant amp(1)=0.7854; amp(2)=0.4861; amp(3)=0.3009; amp(4)=0.1863; amp(5)=0.1153; amp(6)=0.0714; amp(7)=0.0442; amp(8)=0.0273; amp(9)=0.0169; amp(10)=0.0105; dts1(1:NP)=0:9; %[amp,dst,dts1]=f_MUL(NP,dt,ds,st1); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% snr=[5,10,15,20,25,30]; for jj=1:length(snr) cn=snr(jj); %%40;%%% dB cn1=10^(-cn/10); LLL=1;%%% Number of trial for KLL=1:LLL; if mod(KLL,1)==0,KLL end %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% zxn1=zeros(1,NP); zyn1=zeros(1,NP); zn1=zeros(1,NP); zn2=zeros(1,NP); phn=zeros(1,NP); amp1=zeros(1,NP); qd3=zeros(1,NNt); %%% Generation of Rayleigh fading %%% Amplitude zxn1(1:NP)=randn(1,NP); zyn1(1:NP)=randn(1,NP); zn1(1:NP)=zxn1(1:NP)+j*zyn1(1:NP); zn2(1:NP)=abs(zn1(1:NP))/sqrt(2); %%% Phase phn(1:NP)=atan2(zyn1(1:NP),zxn1(1:NP)); amp1(1:NP)=zn2(1:NP).*amp(1:NP).*exp(j*phn(1:NP)); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ya=zeros(L,M); x3=zeros(L,N); L1=N/2+1-M/2; L2=N/2+M/2; %%%%%%%%%%%%%Data generation %%%%%%%%%%%%%% ya(1:L,1:M)=randint(L,M,MMMa); %%%%%%%%%%%%% Modulation %%%%%%%%% x3(1:L,L1:L2)=f_EnMQAM(ya(1:L,1:M),MMMa); %%%%%%%%%%%Converting from Frequency to Time domain signal %%%%%%%%% for k=1:L; zz1(k,1:N)=ifft(fftshift(x3(k,1:N)))*sqrt(N); %%%% Adding Guard Interval z3(k,1:Nt)=[zz1(k,N-Ng+1:N) zz1(k,1:N)]; end q13=z3'; q73=q13(:)'; %%%%%%%%%% Evaluation of Power Spectrum under AWGN condition q73a=fftshift(fft(q73)); pow1=q73a.*conj(q73a); pow2=10*log10(pow1/max(pow1)); %%%%%%%%%%% po3=mean(q73.*conj(q73)); c3=po3/2*cn1; %%%%%% Noise Generation %%%%% zxc(1:L,1:Nt)=sqrt(c3).*randn(L,Nt); zyc(1:L,1:Nt)=sqrt(c3).*randn(L,Nt); znc(1:L,1:Nt)=zxc(1:L,1:Nt)+j*zyc(1:L,1:Nt); znn1c=znc'; znnc=znn1c(:)'; qd3(1:NNt)=amp1(1).*q73(1:NNt); %%%% Generation of Multi-path fading signal for k=2:NP; qu23(k,1:NNt)=[q73(NNt+1-dts1(k):NNt) q73(1:NNt-dts1(k))]; qu23(k,1:NNt)=amp1(k).*qu23(k,1:NNt); qd3(1:NNt)=qd3(1:NNt)+qu23(k,1:NNt); end %%%%%%%%%% Evaluation of Power Spectrum under multi-path fading condition qd3a=fftshift(fft(qd3)); pow3=qd3a.*conj(qd3a); pow4=10*log10(pow3/max(pow3)); %%%% Adding AWGN q73x=qd3+znnc; q73y=q73+znnc; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% imax=1; %%% Removing Guard interval for k=1:L; p93(k,1:Nt)=q73x(imax-1+(k-1)*Nt+(1:Nt)); p993(k,1:N)=[p93(k,Ng+1:N+Ng)]; %%%%%%%%%% FFT %%%%% p813(k,1:N)=fftshift(fft(p993(k,1:N))/sqrt(N)); HH3(1:M)=p813(1,L1:L2)./x3(1,L1:L2); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% p8x3(k,1:M)=p813(k,L1:L2)./HH3(1:M); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% p93y(k,1:Nt)=q73y(imax-1+(k-1)*Nt+(1:Nt)); p993y(k,1:N)=[p93y(k,Ng+1:N+Ng)]; %%%%%%%%%%%%%%%%%%%%%%%%%%%% p813y(k,1:N)=fftshift(fft(p993y(k,1:N))/sqrt(N)); p8y3(k,1:M)=p813y(k,L1:L2); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% end %%% Demodulation of signal under AWGN pb1(1:L,1:M)=f_DeMQAM(p8x3(1:L,1:M),MMMa);%%% %%% evaluation of bit error rate performance per1(jj,KLL)=biterr(pb1(2:L,1:M),ya(2:L,1:M))/(M*(L-1)*MMM1a); %%% Demodulation of signal under multi-path fading pb2(1:L,1:M)=f_DeMQAM(p8y3(1:L,1:M),MMMa);%%% per2(jj,KLL)=biterr(pb2(2:L,1:M),ya(2:L,1:M))/(M*(L-1)*MMM1a); end end %%%% Final BER ERR1=mean(per1(1:LLL)); ERR2=mean(per2(1:LLL)); %%%%%%%%%%%%%%%%%%%%%%%% figure(1)%%%%%% Information Real Data in Freq semilogy(snr,per1); etime(clock,t0)/60