> On Aug 3, 4:27 am, "JALEX" <joginale...@yahoo.co.in> wrote:
> > Hi
> >
> > I am trying to generate aOFDMsignal withCFO, of which i am trying to
> > plot a BER Vs theCFOfor various SNR....
> >
> > I started by transmitting a signal and receiving it over a flat fading
> > channel, using cyclic prefix, and zero padding the data....
> > which I was successful
> >
> > But when i tried it over theCFO.....i am not getting it...
> > The following is the section of theCFOwhich I use in the channel.
> >
> > f = 11.424*(10^6); %Sampling frequency
> > F = f/Sub; %Sub Carrier Spacing
> > t = 1:0.1:11.79;
> > Constant=rand();
> > CFO= Constant*exp(2*pi*j*F.*t); %carrier frequency offset
> > [a,b]=size(CFO);
> > while(s~=b)
> > TX_SIG = TX_SIG1.*CFO(1,s);
> > Could someone help me on this and let me know where i am wrong.
> >
> > regards
>
>
> I'm assuming CFO means carrier frequency offset, and you're simulating
> at complex baseband. Also, that the CFO remains constant over a given
> time period i.e. for the entire BER trial since that is what you are
> attempting to compare. If you have alternative definitions/
> assumptions then make them clear.
>
> tx_sig represents your transmitted signal with samples spaced by Ts
> seconds
>
> N is the number of samples in a given time period
>
> n = ([0:N-1]*Ts);
> F = 1; % freq offset in Hz
> CFO = exp(j*2*pi*F*n); % unit amplitude complex exponential
>
> rx_sig = tx_sig .* CFO;
>
> what's your problem?
>
> col
One problem that I wanted him to figure out was that the way he
created his code, he was applying a constant CFO equal to one
subcarrier spacing using a randomly scaled complex exponential series.
Based on these obvious errors, he seemed as though he needed practice
in problem solving as well as in systematic debugging process. He may
also need to learn his theory a little better.
Phil
P.S. I assume that the originator was a 'he'.
Reply by ●August 7, 20072007-08-07
On Aug 3, 4:27 am, "JALEX" <joginale...@yahoo.co.in> wrote:
> Hi
>
> I am trying to generate aOFDMsignal withCFO, of which i am trying to
> plot a BER Vs theCFOfor various SNR....
>
> I started by transmitting a signal and receiving it over a flat fading
> channel, using cyclic prefix, and zero padding the data....
> which I was successful
>
> But when i tried it over theCFO.....i am not getting it...
> The following is the section of theCFOwhich I use in the channel.
>
> f = 11.424*(10^6); %Sampling frequency
> F = f/Sub; %Sub Carrier Spacing
> t = 1:0.1:11.79;
> Constant=rand();
> CFO= Constant*exp(2*pi*j*F.*t); %carrier frequency offset
> [a,b]=size(CFO);
> while(s~=b)
> TX_SIG = TX_SIG1.*CFO(1,s);
> Could someone help me on this and let me know where i am wrong.
>
> regards
I'm assuming CFO means carrier frequency offset, and you're simulating
at complex baseband. Also, that the CFO remains constant over a given
time period i.e. for the entire BER trial since that is what you are
attempting to compare. If you have alternative definitions/
assumptions then make them clear.
tx_sig represents your transmitted signal with samples spaced by Ts
seconds
N is the number of samples in a given time period
n = ([0:N-1]*Ts);
F = 1; % freq offset in Hz
CFO = exp(j*2*pi*F*n); % unit amplitude complex exponential
rx_sig = tx_sig .* CFO;
what's your problem?
col
Reply by JALEX●August 5, 20072007-08-05
>On Aug 3, 6:27 am, "JALEX" <joginale...@yahoo.co.in> wrote:
>> Hi
>>
>> I am trying to generate a OFDM signal with CFO, of which i am trying
to
>> plot a BER Vs the CFO for various SNR....
>>
>> I started by transmitting a signal and receiving it over a flat fading
>> channel, using cyclic prefix, and zero padding the data....
>> which I was successful
>>
>> But when i tried it over the CFO .....i am not getting it...
>> The following is the section of the CFO which I use in the channel.
>>
>> f = 11.424*(10^6); %Sampling frequency
>> F = f/Sub; %Sub Carrier Spacing
>> t = 1:0.1:11.79;
>> Constant=rand();
>> CFO = Constant*exp(2*pi*j*F.*t); %carrier frequency
offset
>> [a,b]=size(CFO);
>> while(s~=b)
>> TX_SIG = TX_SIG1.*CFO(1,s);
>> Could someone help me on this and let me know where i am wrong.
>>
>> regards
>
>I'm not going to debug your Matlab code for you, but
>I suspect it's a programming error in the way you try
>to apply this mysterious "CFO" (what is CFO anyway?)
>to both frequency bins and different time indices at
>the same time.
>
>Julius
>
Hi Julius
Well i have changed the format of the Carrier frequency Offset....
Basically i am trying to plot BER/CFO ans I ran the program for
theta=0:30;
CFO(n) = exp(j*theta(n)); %carrier frequency offset
TX_SIG = TX_SIG1.*CFO(n);
>Where the TX_SIG is the transmitted data after IFFT and adding of cyclic
prefix.
But when i run the program for varoius iterration for a particular
SNR=30..i am not getting any graph...rather the BER is showing to be
zero..
i would like to know whether my CFO is right or else how should I multiply
the Frequency offset to the signal
Reply by julius●August 5, 20072007-08-05
On Aug 3, 6:27 am, "JALEX" <joginale...@yahoo.co.in> wrote:
> Hi
>
> I am trying to generate a OFDM signal with CFO, of which i am trying to
> plot a BER Vs the CFO for various SNR....
>
> I started by transmitting a signal and receiving it over a flat fading
> channel, using cyclic prefix, and zero padding the data....
> which I was successful
>
> But when i tried it over the CFO .....i am not getting it...
> The following is the section of the CFO which I use in the channel.
>
> f = 11.424*(10^6); %Sampling frequency
> F = f/Sub; %Sub Carrier Spacing
> t = 1:0.1:11.79;
> Constant=rand();
> CFO = Constant*exp(2*pi*j*F.*t); %carrier frequency offset
> [a,b]=size(CFO);
> while(s~=b)
> TX_SIG = TX_SIG1.*CFO(1,s);
> Could someone help me on this and let me know where i am wrong.
>
> regards
I'm not going to debug your Matlab code for you, but
I suspect it's a programming error in the way you try
to apply this mysterious "CFO" (what is CFO anyway?)
to both frequency bins and different time indices at
the same time.
Julius
Reply by John●August 4, 20072007-08-04
On Aug 4, 9:18 am, "JALEX" <joginale...@yahoo.co.in> wrote:
> >JALEX wrote:
> >> Hi
>
> >> I am trying to generate a OFDM signal with CFO, of which i am trying
> to
> >> plot a BER Vs the CFO for various SNR....
>
> >> I started by transmitting a signal and receiving it over a flat fading
> >> channel, using cyclic prefix, and zero padding the data....
> >> which I was successful
>
> >> But when i tried it over the CFO .....i am not getting it...
> >> The following is the section of the CFO which I use in the channel.
>
> >> f = 11.424*(10^6); %Sampling frequency
> >> F = f/Sub; %Sub Carrier Spacing
> >> t = 1:0.1:11.79;
> >> Constant=rand();
> >> CFO = Constant*exp(2*pi*j*F.*t); %carrier frequency
> offset
> >> [a,b]=size(CFO);
> >> while(s~=b)
> >> TX_SIG = TX_SIG1.*CFO(1,s);
> >> Could someone help me on this and let me know where i am wrong.
>
> >> regards
>
> >CFO should be a unit-amplitude complex exponential rotating at the
> >desired offset frequency (zero Hz == no offset).
>
> >John
>
> Hi John .....Thanks for replying
>
> So by putting the value of 'Constant' as unity.....is it the way to
> achieve the CFO on the tranmitted signal.
Help me out here Vladimir.
John
Reply by JALEX●August 4, 20072007-08-04
>JALEX wrote:
>> Hi
>>
>> I am trying to generate a OFDM signal with CFO, of which i am trying
to
>> plot a BER Vs the CFO for various SNR....
>>
>> I started by transmitting a signal and receiving it over a flat fading
>> channel, using cyclic prefix, and zero padding the data....
>> which I was successful
>>
>> But when i tried it over the CFO .....i am not getting it...
>> The following is the section of the CFO which I use in the channel.
>>
>> f = 11.424*(10^6); %Sampling frequency
>> F = f/Sub; %Sub Carrier Spacing
>> t = 1:0.1:11.79;
>> Constant=rand();
>> CFO = Constant*exp(2*pi*j*F.*t); %carrier frequency
offset
>> [a,b]=size(CFO);
>> while(s~=b)
>> TX_SIG = TX_SIG1.*CFO(1,s);
>> Could someone help me on this and let me know where i am wrong.
>>
>> regards
>>
>>
>
>CFO should be a unit-amplitude complex exponential rotating at the
>desired offset frequency (zero Hz == no offset).
>
>John
>
Hi John .....Thanks for replying
So by putting the value of 'Constant' as unity.....is it the way to
achieve the CFO on the tranmitted signal.
Reply by JALEX●August 4, 20072007-08-04
>> CFO = Constant*exp(2*pi*j*F.*t); %carrier frequency
offset
>
>Why are you multiplying your vector of complex exponentials by the
>random number?
>
>Phil
>
>
Hi Phil thanks for replying....
I put up constant value to normalise the CFO that has to be multiplied to
the signal.
Reply by John Sampson●August 3, 20072007-08-03
JALEX wrote:
> Hi
>
> I am trying to generate a OFDM signal with CFO, of which i am trying to
> plot a BER Vs the CFO for various SNR....
>
> I started by transmitting a signal and receiving it over a flat fading
> channel, using cyclic prefix, and zero padding the data....
> which I was successful
>
> But when i tried it over the CFO .....i am not getting it...
> The following is the section of the CFO which I use in the channel.
>
> f = 11.424*(10^6); %Sampling frequency
> F = f/Sub; %Sub Carrier Spacing
> t = 1:0.1:11.79;
> Constant=rand();
> CFO = Constant*exp(2*pi*j*F.*t); %carrier frequency offset
> [a,b]=size(CFO);
> while(s~=b)
> TX_SIG = TX_SIG1.*CFO(1,s);
> Could someone help me on this and let me know where i am wrong.
>
> regards
>
>
CFO should be a unit-amplitude complex exponential rotating at the
desired offset frequency (zero Hz == no offset).
John
Reply by Phil●August 3, 20072007-08-03
> CFO = Constant*exp(2*pi*j*F.*t); %carrier frequency offset
Why are you multiplying your vector of complex exponentials by the
random number?
Phil
Reply by JALEX●August 3, 20072007-08-03
Hi
I am trying to generate a OFDM signal with CFO, of which i am trying to
plot a BER Vs the CFO for various SNR....
I started by transmitting a signal and receiving it over a flat fading
channel, using cyclic prefix, and zero padding the data....
which I was successful
But when i tried it over the CFO .....i am not getting it...
The following is the section of the CFO which I use in the channel.
f = 11.424*(10^6); %Sampling frequency
F = f/Sub; %Sub Carrier Spacing
t = 1:0.1:11.79;
Constant=rand();
CFO = Constant*exp(2*pi*j*F.*t); %carrier frequency offset
[a,b]=size(CFO);
while(s~=b)
TX_SIG = TX_SIG1.*CFO(1,s);
Could someone help me on this and let me know where i am wrong.
regards