Re: Fwd: [Discuss-gnuradio] Ofdm parameters

[Jacopo]

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 Rondeau <address@hidden>:

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


> 2008/2/2, Matt Ettus <address@hidden <mailto:address@hidden>>:
>
>     Jacopo wrote:
>     > Hello I'm studing an OFDM implementation on gnuradio. I want to
>     modify
>     > benchmark_ofdm_tx.py.
>     >
>     > I have just read ofdm.py and trasmit_path.py but I can't find how
>     > change some parameters.
>     >
>     > I'd want a bandwith of 20Mhz, where I can set this option? Where
>     can I
>     > set the carriers number? And the pilot bins?
>     >
>     > 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
>

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