Problem with simulating OFDM in Matlab

dear sir

i am smulating ofdm in matlab

but in this mentioned code i am not able to draw graph between ci and ber(ie snr n bit error rate only one point is displayed .

plz have a look

and help

where i went wrong plz correct

thanks

dhruva

% Simulate effect of interfarence noise

%

%

% GI CE GI data GI data...(data 6symbols)

%


%********************** preparation part ***************************


para=52; % Number of parallel channel to transmit (points)

fftlen=64; % FFT length

noc=53; % Number of carriers

nd=6; % Number of information OFDM symbol for one loop

knd=1; % Number of known channel estimation (CE) OFDM symbol

ml=2; % Modulation level : QPSK

sr=250000; % OFDM symbol rate (250 ksyombol/s)

br=sr.*ml; % Bit rate per carrier

gilen=16; % Length of guard interval (points)

ebn0=1000; % Eb/N0


%---------------------- fading initialization ----------------------


tstp=1/sr/(fftlen+gilen); % Time resolution

itau=[0]; % Arrival time for each multipath normalized by tstp

dlvl1=[0]; % Mean power for each multipath normalized by direct wave.

n0=[6]; % Number of waves to generate fading n0(1),n0(2)

th1=[0.0]; % Initial Phase of delayed wave

itnd1=[1000]; % set fading counter

now1=1; % Number of directwave + Number of delayed wave

fd=150; % Maximum Doppler frequency

flat=0; % Flat or not (see ofdm_fading.m)

itnd0=nd*(fftlen+gilen)*10; % Number of fading counter to skip


%----------------- interference wave initialization --------------------


ci=10; % C/I ratio

ml2=2; % modulation level


itau2=[0];

dlvl2=[0];

n02=[6];

th2=[0.0];

itnd2=[10000+floor(rand(1)*10)*1000];

now2=1;

fd2=fd;

flat2=0;

itnd02=nd*(fftlen+gilen)*300; % Number of fading counter to skip


%% store all parameters in one matrix "fadingpara"


fadingpara=zeros(8,length(itau2));

fadingpara(1,=itau2;

fadingpara(2,=dlvl2;

fadingpara(3,=n02;

fadingpara(4,=th2;

fadingpara(5,=itnd2;

fadingpara(6,=now2;

fadingpara(7,=fd2;

fadingpara(8,=flat2;


%************************** main loop part **************************


nloop=1000; % Number of simulation loops


noe = 0; % Number of error data

nod = 0; % Number of transmitted data

eop=0; % Number of error packet

nop=0; % Number of transmitted packet


%************************** transmitter *****************************

for iii=1:nloop


seldata=rand(1,para*nd*ml)>0.5; % DC=0


paradata=reshape(seldata,para,nd*ml); %size(51 * nd*ml)


%-------------- ml modulation ----------------


[ich,qch]=qpskmod(paradata,para,nd,ml);

kmod=1/sqrt(2);

ich=ich.*kmod;

qch=qch.*kmod;


% CE data generation

kndata=zeros(1,fftlen);

kndata0=2.*(rand(1,52)>0.5)-1;

kndata(2:27)=kndata0(1:26);

kndata(39:64)=kndata0(27:52);

ceich=kndata; % CE:BPSK

ceqch=zeros(1,64);


%------------- data mapping (DC=0) -----------


[ich1,qch1]=crmapping(ich,qch,fftlen,nd);


ich2=[ceich.' ich1]; % I-channel transmission data

qch2=[ceqch.' qch1]; % Q-channel transmission data


%------------------- IFFT -------------------


x=ich2+qch2.*i;

y=ifft(x);

ich3=real;

qch3=imag;


%---------- Gurad interval insertion ---------


fftlen2=fftlen+gilen;

[ich4,qch4]= giins(ich3,qch3,fftlen,gilen,nd+1);


%---------- Attenuation Calculation ----------

spow=sum(ich4.^2+qch4.^2)/nd./52;

attn=0.5*spow*sr/br*10.^(-ebn0/10);

attn=sqrt(attn);



%********************** fading channel ******************************

%If you would like to simulate performance under fading, please remove "*"

%from the following four sentenses

[ifade,qfade,ramp,rcos,rsin]=sefade(ich4,qch4,itau,dlvl1,th1,n0,itnd1,now1,length(ich4),tstp,fd,flat);

itnd1 = itnd1+itnd0; % Updata fading counter

ich4=ifade;

qch4=qfade;


%%% interference wave addition

% interference

[iintw,qintw]=interwave(ci,spow,ml2,length(ich4),tstp,fadingpara);

itnd2 = itnd2+itnd02;

fadingpara(5,=itnd2;

ich4=ich4+iintw;

qch4=qch4+qintw;


%*************************** Receiver *****************************

%--------------- AWGN addition ---------------

[ich5,qch5]=comb(ich4,qch4,attn);


%----Perfect fading compensation for one path fading ----

%If you would like to simulate performance under perfect compensation, please remove "*"

%from the following four sentenses

%ifade2=1./ramp.*(rcos(1,.*ich5+rsin(1,.*qch5);

%qfade2=1./ramp.*(-rsin(1,.*ich5+rcos(1,.*qch5);

%ich5=ifade2;

%qch5=qfade2;


%----------- Guard interval removal ----------


[ich6,qch6]= girem(ich5,qch5,fftlen2,gilen,nd+1);


%------------------ FFT --------------------


rx=ich6+qch6.*i;

ry=fft(rx);

ich7=real(ry);

qch7=imag(ry);


%-------------- Fading compensation by CE symbol --------------

%

%If you would like to simulate performance under CE-based compensation, please remove "*"

%in this area

%


% preparation known CE data

ce=1;

ice0=ich2,ce);

qce0=qch2,ce);


% taking CE data out of received data

ice1=ich7,ce);

qce1=qch7,ce);


% calculating reverse rotation

iv=real((1./(ice1.^2+qce1.^2)).*(ice0+i.*qce0).*(ice1-i.*qce1));

qv=imag((1./(ice1.^2+qce1.^2)).*(ice0+i.*qce0).*(ice1-i.*qce1));


% matrix for reverse rotation

ieqv1=[iv iv iv iv iv iv iv];

qeqv1=[qv qv qv qv qv qv qv];


% reverse rotation

icompen=real((ich7+i.*qch7).*(ieqv1+i.*qeqv1));

qcompen=imag((ich7+i.*qch7).*(ieqv1+i.*qeqv1));

ich7=icompen;

qch7=qcompen;


%---------- CE symbol removal ----------------


ich8=ich7,knd+1:nd+1);

qch8=qch7,knd+1:nd+1);


%---------- DC and pilot data removal --------


[ich9,qch9]=crdemapping(ich8,qch8,fftlen,nd);


%----------------- demoduration --------------


ich10=ich9./kmod;

qch10=qch9./kmod;

[demodata]=qpskdemod(ich10,qch10,para,nd,ml);


%-------------- error calculation ----------


demodata1=reshape(demodata,1,para*nd*ml);

noe2=sum(abs(demodata1-seldata));

nod2=length(seldata);


% calculating PER

if noe2~=0

eop=eop+1;

else

eop=eop;

end

eop;

nop=nop+1;


% calculating BER

noe=noe+noe2;

nod=nod+nod2;


fprintf('%d\t%e\t%d\n',iii,noe2/nod2,eop);

per=eop/nop;

ber=noe/nod;

semilogy(ci,ber,'-*');

legend('ber performance');

xlabel('snr');

ylabel('ber');

end



%********************** Output result ***************************


fprintf('%f\t%e\t%e\t%d\t%d\n',ci,ber,per,nloop,fd);


fid = fopen('BERofdmci.dat','a');

fprintf(fid,'%f\t%e\t%e\t%d\t%d\n',ci,ber,per,nloop,fd);

fclose(fid);


%******************** end of file ***************************

% Simulate effect of interfarence noise

%

%

% GI CE GI data GI data...(data 6symbols)

%


%********************** preparation part ***************************


para=52; % Number of parallel channel to transmit (points)

fftlen=64; % FFT length

noc=53; % Number of carriers

nd=6; % Number of information OFDM symbol for one loop

knd=1; % Number of known channel estimation (CE) OFDM symbol

ml=2; % Modulation level : QPSK

sr=250000; % OFDM symbol rate (250 ksyombol/s)

br=sr.*ml; % Bit rate per carrier

gilen=16; % Length of guard interval (points)

ebn0=1000; % Eb/N0


%---------------------- fading initialization ----------------------


tstp=1/sr/(fftlen+gilen); % Time resolution

itau=[0]; % Arrival time for each multipath normalized by tstp

dlvl1=[0]; % Mean power for each multipath normalized by direct wave.

n0=[6]; % Number of waves to generate fading n0(1),n0(2)

th1=[0.0]; % Initial Phase of delayed wave

itnd1=[1000]; % set fading counter

now1=1; % Number of directwave + Number of delayed wave

fd=150; % Maximum Doppler frequency

flat=0; % Flat or not (see ofdm_fading.m)

itnd0=nd*(fftlen+gilen)*10; % Number of fading counter to skip


%----------------- interference wave initialization --------------------


ci=10; % C/I ratio

ml2=2; % modulation level


itau2=[0];

dlvl2=[0];

n02=[6];

th2=[0.0];

itnd2=[10000+floor(rand(1)*10)*1000];

now2=1;

fd2=fd;

flat2=0;

itnd02=nd*(fftlen+gilen)*300; % Number of fading counter to skip


%% store all parameters in one matrix "fadingpara"


fadingpara=zeros(8,length(itau2));

fadingpara(1,=itau2;

fadingpara(2,=dlvl2;

fadingpara(3,=n02;

fadingpara(4,=th2;

fadingpara(5,=itnd2;

fadingpara(6,=now2;

fadingpara(7,=fd2;

fadingpara(8,=flat2;


%************************** main loop part **************************


nloop=1000; % Number of simulation loops


noe = 0; % Number of error data

nod = 0; % Number of transmitted data

eop=0; % Number of error packet

nop=0; % Number of transmitted packet


%************************** transmitter *****************************

for iii=1:nloop


seldata=rand(1,para*nd*ml)>0.5; % DC=0


paradata=reshape(seldata,para,nd*ml); %size(51 * nd*ml)


%-------------- ml modulation ----------------


[ich,qch]=qpskmod(paradata,para,nd,ml);

kmod=1/sqrt(2);

ich=ich.*kmod;

qch=qch.*kmod;


% CE data generation

kndata=zeros(1,fftlen);

kndata0=2.*(rand(1,52)>0.5)-1;

kndata(2:27)=kndata0(1:26);

kndata(39:64)=kndata0(27:52);

ceich=kndata; % CE:BPSK

ceqch=zeros(1,64);


%------------- data mapping (DC=0) -----------


[ich1,qch1]=crmapping(ich,qch,fftlen,nd);


ich2=[ceich.' ich1]; % I-channel transmission data

qch2=[ceqch.' qch1]; % Q-channel transmission data


%------------------- IFFT -------------------


x=ich2+qch2.*i;

y=ifft(x);

ich3=real;

qch3=imag;


%---------- Gurad interval insertion ---------


fftlen2=fftlen+gilen;

[ich4,qch4]= giins(ich3,qch3,fftlen,gilen,nd+1);


%---------- Attenuation Calculation ----------

spow=sum(ich4.^2+qch4.^2)/nd./52;

attn=0.5*spow*sr/br*10.^(-ebn0/10);

attn=sqrt(attn);



%********************** fading channel ******************************

%If you would like to simulate performance under fading, please remove "*"

%from the following four sentenses

[ifade,qfade,ramp,rcos,rsin]=sefade(ich4,qch4,itau,dlvl1,th1,n0,itnd1,now1,length(ich4),tstp,fd,flat);

itnd1 = itnd1+itnd0; % Updata fading counter

ich4=ifade;

qch4=qfade;


%%% interference wave addition

% interference

[iintw,qintw]=interwave(ci,spow,ml2,length(ich4),tstp,fadingpara);

itnd2 = itnd2+itnd02;

fadingpara(5,=itnd2;

ich4=ich4+iintw;

qch4=qch4+qintw;


%*************************** Receiver *****************************

%--------------- AWGN addition ---------------

[ich5,qch5]=comb(ich4,qch4,attn);


%----Perfect fading compensation for one path fading ----

%If you would like to simulate performance under perfect compensation, please remove "*"

%from the following four sentenses

%ifade2=1./ramp.*(rcos(1,.*ich5+rsin(1,.*qch5);

%qfade2=1./ramp.*(-rsin(1,.*ich5+rcos(1,.*qch5);

%ich5=ifade2;

%qch5=qfade2;


%----------- Guard interval removal ----------


[ich6,qch6]= girem(ich5,qch5,fftlen2,gilen,nd+1);


%------------------ FFT --------------------


rx=ich6+qch6.*i;

ry=fft(rx);

ich7=real(ry);

qch7=imag(ry);


%-------------- Fading compensation by CE symbol --------------

%

%If you would like to simulate performance under CE-based compensation, please remove "*"

%in this area

%


% preparation known CE data

ce=1;

ice0=ich2,ce);

qce0=qch2,ce);


% taking CE data out of received data

ice1=ich7,ce);

qce1=qch7,ce);


% calculating reverse rotation

iv=real((1./(ice1.^2+qce1.^2)).*(ice0+i.*qce0).*(ice1-i.*qce1));

qv=imag((1./(ice1.^2+qce1.^2)).*(ice0+i.*qce0).*(ice1-i.*qce1));


% matrix for reverse rotation

ieqv1=[iv iv iv iv iv iv iv];

qeqv1=[qv qv qv qv qv qv qv];


% reverse rotation

icompen=real((ich7+i.*qch7).*(ieqv1+i.*qeqv1));

qcompen=imag((ich7+i.*qch7).*(ieqv1+i.*qeqv1));

ich7=icompen;

qch7=qcompen;


%---------- CE symbol removal ----------------


ich8=ich7,knd+1:nd+1);

qch8=qch7,knd+1:nd+1);


%---------- DC and pilot data removal --------


[ich9,qch9]=crdemapping(ich8,qch8,fftlen,nd);


%----------------- demoduration --------------


ich10=ich9./kmod;

qch10=qch9./kmod;

[demodata]=qpskdemod(ich10,qch10,para,nd,ml);


%-------------- error calculation ----------


demodata1=reshape(demodata,1,para*nd*ml);

noe2=sum(abs(demodata1-seldata));

nod2=length(seldata);


% calculating PER

if noe2~=0

eop=eop+1;

else

eop=eop;

end

eop;

nop=nop+1;


% calculating BER

noe=noe+noe2;

nod=nod+nod2;


fprintf('%d\t%e\t%d\n',iii,noe2/nod2,eop);

per=eop/nop;

ber=noe/nod;

semilogy(ci,ber,'-*');

legend('ber performance');

xlabel('snr');

ylabel('ber');

end



%********************** Output result ***************************


fprintf('%f\t%e\t%e\t%d\t%d\n',ci,ber,per,nloop,fd);


fid = fopen('BERofdmci.dat','a');

fprintf(fid,'%f\t%e\t%e\t%d\t%d\n',ci,ber,per,nloop,fd);

fclose(fid);


%******************** end of file ***************************