Fwd: Ofdm parameters

GNU Radio
1

Thanks! But where can i check this parameter?

Is it possible that fft_length= occupated carrier (–occupied-tones in
blksimpl/ofdm.py) + un_used carrier ? Where can i set the position of
the
occupated_bins?

bye

2008/2/2, Matt E. [email protected]:

Is it possible to set an adaptive modulation for differents carriers?

The USRP hardware is not capable of bandwidths that high. You are best
off staying around 6 MHz.

Matt

–
www.fotofestefirenze.it

2

Jacopo wrote:

Thanks! But where can i check this parameter?

Is it possible that fft_length= occupated carrier (–occupied-tones in
blksimpl/ofdm.py) + un_used carrier ? Where can i set the position of
the occupated_bins?

bye

To modify the bandwidth, you have to set the interpolation and
decimation rates. Yes, fft_length is the size of the FFT or total number
of subcarriers. Of this, only occupied-tones are used to carry data. The
unused carriers are distributed evenly on the carriers and you cannot
modify this behavior in the parameters currently, i.e., we do not
support non-contiguous OFDM.

Tom

3

Thanks a lot!!!

Another question: It’s possible to have adaptive modulation, that is the
possibility to use different modulation for any subcarrier?

Bye

Jacopo

2008/2/3, Thomas R. [email protected]:

4

Jacopo wrote:

Thanks a lot!!!

Another question: It’s possible to have adaptive modulation, that is
the possibility to use different modulation for any subcarrier?

Bye

Jacopo

No, not in the current implementation. You’ll have to create a new
ofdm_modulator block to handle this behavior.

On that note, that’s really the entire point of what we’ve created (or
will have once the issues are all worked out). We wanted to show the
basics of a general OFDM modulator/demodulator so that others can build
from there with their own interesting stuff.

Tom

5

On Sun, Feb 03, 2008 at 05:59:06PM +0100, Jacopo wrote:

Thanks a lot!!!

Another question: It’s possible to have adaptive modulation, that is the
possibility to use different modulation for any subcarrier?

Bye

Jacopo

It’s definitely possible. The main question is how to design an
interface that isn’t hideous. If you want this, I think you should
work on it and let us know what you come up with.

Eric