%?OFDM_basic.m

%MIMO-OFDM?Wireless?Communications?with?MATLAB㈢???Yong?Soo?Cho?Jaekwon?Kim?Won?Young?Yang?and?Chung?G.?Kang
%?2010?John?Wiley?&?Sons?（Asia）?Pte?Ltd

clear?all
NgType=1;?%?NgType=1/2?for?cyclic?prefix/zero?padding
if?NgType==1
????nt=‘CP‘;
else
????if?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‘;???%CH=1?多徑衰落
????????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=3;?%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=[0:5:20];????%?EbN0
????N_iter=1e5;???????%?Number?of?iterations?for?each?EbN0
????Nframe=3;?????????%?Number?of?symbols?per?frame每一幀符號數
????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
????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（1Nused*NframeM）;?%?bit:?integer?vector
????????????Xmod=?qammod（XM0‘gray‘）/norms（Nbps）;
????????????if?NgType~=2
????????????????x_GI=zeros（1Nframe*Nsym）;
????????????elseif?NgType==2
????????????????x_GI=?zeros（1Nframe*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（1Nvc-1）?Xmod（kk1）];
????????????????else
????????????????????X_shift=?[Xmod（kk2）?Xmod（kk1）];
????????????????end
????????????????x=?ifft（X_shift）;
????????????????x_GI（kk4）=?guard_interval（NgNfftNgTypex）;
?????????