OFDM.zip_ofdm误码

function ber=ofdm_fading(ebn0) % Program 4-2 % ofdm_fading.m % % Simulation program to realize OFDM transmission system % (under one path fading) % % programmed by T.Yamamura and H.Harada % revised by liqizhen %********************** preparation part *************************** para=128; % Number of parallel channel to transmit (points) fftlen=128; % FFT length noc=128; % Number of carrier nd=6; % Number of information OFDM symbol for one loop ml=1; % Modulation level : BPSK sr=250000; % Symbol rate br=sr.*ml; % Bit rate per carrier gilen=32; % Length of guard interval (points) %******************* Fading initialization ******************** % If you use fading function "sefade", you can initialize all of parameters. % Otherwise you can comment out the following initialization. % The detailed explanation of all of valiables are mentioned in Program 2-8. % Time resolution tstp=1/sr/(fftlen+gilen); % Arrival time for each multipath normalized by tstp % If you would like to simulate under one path fading model, you have only to set % direct wave. itau = [0]; % Mean power for each multipath normalized by direct wave. % If you would like to simulate under one path fading model, you have only to set % direct wave. dlvl = [0]; % Number of waves to generate fading for each multipath. % In normal case, more than six waves are needed to generate Rayleigh fading n0=[6]; % Initial Phase of delayed wave % In this simulation four-path Rayleigh fading are considered. th1=[0.0]; % Number of fading counter to skip itnd0=nd*(fftlen+gilen)*10; % Initial value of fading counter % In this simulation one-path Rayleigh fading are considered. % Therefore one fading counter are needed. itnd1=[1000]; % Number of directwave + Number of delayed wave % In this simulation one-path Rayleigh fading are considered now1=1; % Maximum Doppler frequency [Hz] % You can insert your favorite value fd=320; % You can decide two mode to simulate fading by changing the variable flat % flat : flat fading or not % (1->flat (only amplitude is fluctuated),0->nomal(phase and amplitude are fluctutated) flat =1; %************************** main loop part ************************** noe = 0; % Number of error data nod = 0; % Number of transmitted data while noe<500 %固定误比特个数为500 %************************** transmitter ********************************* %************************** Data generation **************************** seldata=rand(1,para*nd*ml)>0; % rand : built in function %****************** Serial to parallel conversion *********************** paradata=reshape(seldata,para,nd*ml); % reshape : built in function %************************** BPSK modulation ***************************** ich1=paradata.*2-1; %变换成双极性信号 %******************* IFFT ************************ x=ich1; %BPSK信号只有同相分量，正交分量为零 y=ifft(x); % ifft : built in function ich2=real(y); % real : built in function qch2=imag(y); % imag : built in function %********* Gurad interval insertion ********** [ich3,qch3]= giins(ich2,qch2,fftlen,gilen,nd); fftlen2=fftlen+gilen; %********* Attenuation Calculation ********* spow=sum(ich3.^2+qch3.^2)/nd./para; % sum : built in function attn=0.5*spow*sr/br*10.^(-ebn0/10); attn=sqrt(attn); %********************** Fading channel ********************** % Generated data are fed into a fading simulator [ifade,qfade]=sefade(ich3,qch3,itau,dlvl,th1,n0,itnd1,now1,length(ich3),tstp,fd,flat); % Updata fading counter itnd1 = itnd1+ itnd0; %*************************** Receiver ***************************** %***************** AWGN addition ********* [ich4,qch4]=comb(ifade,qfade,attn); %****************** Guard interval removal ********* [ich5,qch5]= girem(ich4,qch4,fftlen2,gilen,nd); %****************** FFT ****************** rx=ich5+qch5.*i; ry=fft(rx); % fft : built in function ich6=real(ry); % real : built in function %***************** BPSK demoduration ******************* demodata=ich6>0; %判决接收信号 %************** Parallel to serial conversion ***************** demodata1=reshape(demodata,1,para*nd*ml); %************************** Bit Error Rate (BER) **************************** % instantaneous number of error and data noe2=sum(abs(demodata1-seldata)); % sum : built in function nod2=length(seldata); % length : built in function % cumulative the number of error and data in noe and nod noe=noe+noe2; %计算误比特个数 nod=nod+nod2; %计算传输比特个数 end %********************** Output result *************************** ber=noe/nod; %计算误比特率 %******************** end of file ***************************