ofdm simulation

8/13/2019 OFDM Simulation

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para=128; % Number of parallel channel

fftlen=128; % FFT length

noc=128; % Number of carrier

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

ml=2; % Modulation level: QPSK

sr=250000; % Symbol rate

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

gilen=32; % Length of guard interval

ebn0=100 % ebn0 : Eb/No

=

nloop=100; % 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


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seridata

seridata=rand(1,para*nd*ml)>0.5;

seridata paradata

paradata=reshape(seridata,para,nd*ml);Next, the vector

paradata was fed into the mapping circuit. In the

circuit, the parallel data were converted into modulated

parallel data of two channels, Ich and Qch by a predefined

mapping method.

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

kmod


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kmod=1/sqrt(2);

ich1=ich.*kmod;

qch1=qch.*kmod;

x=ich1+qch1.*i;

y=ifft(x); % ifft : built-in function

ich2=real(y); % real : built-in function

qch2=imag(y); % imag : built-in function

ich2 qch2

[ich3,qch3]= giins(ich2,qch2,fftlen,gilen,nd);

fftlen2=fftlen+gilen;

fftlen2


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comb.m

attn attn spow spow para

spow=sum(ich3.^qch3)./nd./para;

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

attn=sqrt(attn);

attn

comb.m

[ich4,qch4]= comb(ich3,qch3,length(ich3),attn);

[ich5,qch5]= girem(ich4,qch4,fftlen2,gilen,nd);

ich5 qch5

rx=ich5+qch5.*i;

ry=fft(rx);

ich6=real(ry);

qch6=imag(ry);

kmod

ich7=ich6./kmod;

qch7=qch6./kmod;

[demodata]=qpskdemod(ich7,qch7,para,nd,ml);

demodata1

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

seridata demodata1


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% instantaneous number of errors and data bits

noe2=sum(abs(seridata-demodata1); nod2=length(seridata);

% cumulative number of errors and data bits in noe and nod

noe=noe+noe2;nod=nod+nod2;

% calculating PER

if noe2~=0

eop=eop+1;

else

eop=eop;

end

eop;

nop=nop+1;

ber=noe/nod;

per=eop/nop;

ofdm

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=


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=

gilen

fftlen2

gilen fftlen2

% Generated data are fed into a fading simulator

[ifade,qfade]=sefade(ich3,qch3,itau,dlv1,th1,n0,itnd1,...

now1,length(ich3),tstp,fd,flat);

% Updata fading counter

itnd1=itnd1+itnd0

flat


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= = =

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paradata=reshape(seridata,para,nd*ml);

paradata


kmod

kmod=1/sqrt(2);

ich1=ich.*kmod;

qch1=qch.*kmod;

Ich Qch

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

ich1 qch1

X=ich1+qch1.*i; % i : complex number

y=ifft(x); % ifft : built-in function

ich2=real(y); % real : built-in function

qch2=imag(y); % imag : built-in function



fftlen2

% %


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comb.m


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attn attn spow


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spow para

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


attn=sqrt(attn);

attn comb.m

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

ich5 qch5


ich6 qch6

rx=ich6+qch6.*i;

ry=fft(rx); % fft : built in function

ich7=real(ry);

qch7=imag(ry);

[ich8,qch8]=crdemapping(ich7,qch7,fftlen,nd);

kmod

[ich8,qch8]=crdemapping(ich7,qch7,fftlen,nd);

ich9=ich8./kmod;

qch9=qch8./kmod;


demodata1


seridata demodata1


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% instantaneous number of errors and data

noe2=sum(abs(demodata1-seldata)); nod2=length(seldata);

% length : built in function

% calculating BERnoe=noe+noe2;

nod=nod+nod2;

% calculating PER

if noe2~=0

eop=eop+1;

else

eop=eop;

end

eop;

nop=nop+1;

per=eop/nop;

ber=noe/nod;

ofdmda.m

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=

gilen

fftlen2

gilen fftlen2

% flat

+


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%CE data generation

Ich

% 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 transmitted data

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

ich2 qch2

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

x=ich2+qch2.*i;

y=ifft(x);

ich3=real(y);

qch3=imag(y);

rx=ich6+qch6.*i;

ry=fft(rx);

ich7=real(ry);

qch7=imag(ry);

%-------- fading compensation by CEsymbol --------

ich7 qch7

% taking pilot data out of received data

ce=1;

ice1=ich7(:,ce);

qce1=qch7(:,ce);


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% preparation known CE data

ce=1;ice0=ich2(:,ce);

qce0=qch2(:,ce);

ice1

qcel

ice0

qce0

ice1

qce1

ice0

qce0

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( )=+

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icel qcelice0 ice1 qce0 qce1

( )=+

icel qcelqce0 ice1 ice0 qce1

% 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));


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% matrices for reverse rotation

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

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

7

ich7 qch7 icompen qcompen ich7 qch7icompen qcompen ieq1 qeq1

icompen ich7 ieqv1 qch7 qeqv1=

qcompen qch7 ieqv1 ich7 qeqv1= +

% 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);

% %----Fading compensationby CE symbol


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%-------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;

% Number of fading counter to skip

itnd02=nd*(fftlen+gilen)*300;

fadingpara

% store all parameters in one matrix fadingpara

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

fadingpara(1,:)=itau2;

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fadingpara(2,:)=dlvl2;

fadingpara(3,:)=n02;

fadingpara(4,:)=th2;

fadingpara(5,:)=itnd2;fadingpara(6,:)=now2;

fadingpara(7,:)=fd2;

fadingpara(8,:)=flat2;

fadingpara

%%% 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;

==


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=

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% Program 4-1

% ofdm.m

%

% Simulation program to realize OFDM transmission system

%

% programmed by T. Yamamura and H. Harada

%

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

para=128; % Number of parallel channel to transmit



nd=6; % Number of information OFDM symbol for

% one loop

ml=2; % Modulation level : QPSK

sr=250000; % Symbol rate


gilen=32; % Length of guard interval (points)

ebn0=3; % Eb/N0

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


noe = 0; % Number of error data

nod = 0; % Number of transmitted data



for iii=1:nloop

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

%****************** Data generation *******************

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

% rand : built in function

%*********** Serial to parallel conversion ************

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

% reshape : built in function

%******************* QPSK modulation ******************


kmod=1/sqrt(2); % sqrt : built in function


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ich1=ich.*kmod;

qch1=qch.*kmod;

%************************ IFFT ************************

x=ich1+qch1.*i;

y=ifft(x); % ifft : built in function

ich2=real(y); % real : built in function

qch2=imag(y); % imag : built in function

%************** Guard interval insertion **************



%**************** Attenuation Calculation *************

spow=sum(ich3.^2+qch3.^2)/nd./para;

% sum : built in function


attn=sqrt(attn);

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

%******************** AWGN addition *******************

[ich4,qch4]=comb(ich3,qch3,attn);

%***************** Guard interval removal *************


%*********************** FFT ************************

rx=ich5+qch5.*i;

ry=fft(rx); % fft : built in functionich6=real(ry); % real : built in function

qch6=imag(ry); % imag : built in function

%********************* demodulation *******************

ich7=ich6./kmod;

qch7=qch6./kmod;


%*********** Parallel to serial conversion ************


%**************** Bit Error Rate (BER) ****************

% instantaneous number of error and data


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


nod2=length(seldata);


% cumulative the number of error and data in noe and nod

noe=noe+noe2;

nod=nod+nod2;

% calculating PER

if noe2~=0

eop=eop+1;

else

eop=eop;

end

eop;

nop=nop+1;

fprintf(%d\t%e\t%d\n,iii,noe2/nod2,eop);

% fprintf : built in function

end

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

per=eop/nop;

ber=noe/nod;

fprintf(%f\t%e\t%e\t%d\t\n,ebn0,ber,per,nloop);

fid = fopen(BERofdm.dat,a);

fprintf(fid,%f\t%e\t%e\t%d\t\n,ebn0,ber,per,nloop);

fclose(fid);

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

% Program 4-2

% ofdm_fading.m

%

% Simulation program to realize OFDM transmission system

% (under one path fading)

%

% programmed by T. Yamamura and H. Harada

%

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

para=128; % Number of parallel channel to transmit



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nd=6; % Number of information OFDM symbol for

% one loop

ml=2; % Modulation level : QPSKsr=250000; % Symbol rate


gilen=32; % Length of guard interval (points)

ebn0=10; % Eb/N0

%*************** Fading initialization ****************

% If you use fading function sefade, you can

% initialize all of the parameters.

% Otherwise you can comment out the following

% initialization.

% The detailed explanations of all of variables 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 one-path Rayleigh fading is

% considered.

th1=[0.0];

% Number of fading counter to skipitnd0=nd*(fftlen+gilen)*10;

% Initial value of fading counter

% In this simulation one-path Rayleigh fading is

% considered.

% Therefore one fading counter is needed.


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itnd1=[1000];

% Number of direct wave + Number of delayed wave

% In this simulation one-path Rayleigh fading is% considered

now1=1;

% Maximum Doppler frequency [Hz]

% You can insert your favorite value

fd=320;

% You can decide two modes to simulate fading by changing

% the variable flat

% flat : flat fading or not% (1-flat (only amplitude is fluctuated),0-normal(phase

% and amplitude are fluctuated))

flat =1;

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


noe = 0; % Number of error datanod = 0; % Number of transmitted data



for iii=1:nloop

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

%****************** Data generation *******************

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

% rand : built in function

%*********** Serial to parallel conversion ************

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

% reshape : built in function

%****************** QPSK modulation *******************


kmod=1/sqrt(2); % sqrt : built in function

ich1=ich.*kmod;

qch1=qch.*kmod;


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%************************ IFFT ************************

x=ich1+qch1.*i;

y=ifft(x); % ifft : built in functionich2=real(y); % real : built in function

qch2=imag(y); % imag : built in function

%************** Guard interval insertion **************



%*************** Attenuation Calculation **************

spow=sum(ich3.^2+qch3.^2)/nd./para;% sum : built in function


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 ***************


%*********************** FFT ************************

rx=ich5+qch5.*i;

ry=fft(rx); % fft : built in function

ich6=real(ry); % real : built in function

qch6=imag(ry); % imag : built in function

%******************** demodulation ********************

ich7=ich6./kmod;

qch7=qch6./kmod;


%*********** Parallel to serial conversion ************


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%**************** Bit Error Rate (BER) ****************

% instantaneous number of error and data

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


nod2=length(seldata);


% cumulative the number of error and data in noe and nod

noe=noe+noe2;

nod=nod+nod2;

% calculating PER

if noe2~=0

eop=eop+1;

else

eop=eop;

end

eop;

nop=nop+1;

fprintf(%d\t%e\t%d\n,iii,noe2/nod2,eop);% fprintf : built in function

end

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

per=eop/nop;

ber=noe/nod;

fprintf(%f\t%e\t%e\t%d\t\n,ebn0,ber,per,nloop);

fid = fopen(BERofdmfad.dat,a);fprintf(fid,%f\t%e\t%e\t%d\t\n,ebn0,ber,per,nloop);

fclose(fid);

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

% Program 4-3

% giins.m

%

% Function to insert guard interval into transmission

% signal

%

% Programmed by T. Yamamura and H. Harada

%


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function [iout,qout]= giins(idata,qdata,fftlen,gilen,nd);

%********************** variables *********************

% idata : Input Ich data

% qdata : Input Qch data

% iout : Output Ich data

% qout : Output Qch data

% fftlen : Length of FFT (points)

% gilen : Length of guard interval (points)

% *****************************************************

idata1=reshape(idata,fftlen,nd);

qdata1=reshape(qdata,fftlen,nd);idata2=[idata1(fftlen-gilen+1:fftlen,:); idata1];

qdata2=[qdata1(fftlen-gilen+1:fftlen,:); qdata1];

iout=reshape(idata2,1,(fftlen+gilen)*nd);

qout=reshape(qdata2,1,(fftlen+gilen)*nd);

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

% Program 4-4

% girem.m

%

% Function to remove guard interval from received signal

%

% Programmed by T. Yamamura and H. Harada

%

function [iout,qout]= girem(idata,qdata,fftlen2,gilen,nd);

%********************** variables *********************

% idata : Input Ich data

% qdata : Input Qch data

% iout : Output Ich data

% qout : Output Qch data

% fftlen2 : Length of FFT (points)

% gilen : Length of guard interval (points)

% nd : Number of OFDM symbols

% *****************************************************

idata2=reshape(idata,fftlen2,nd);

qdata2 reshape(qdata fftlen2 nd);

ofdm simulation

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