Re: [Discuss-gnuradio] Benchmark_ofdm_tx Benchmark_ofdm_rx

[Eric Blossom]

On Tue, Jul 01, 2008 at 04:54:22PM +0200, matteo zunino wrote:
> > On Tue, Jul 01, 2008 at 11:37:22AM +0200, matteo zunino wrote:
> > > 
> > > Hi,
> > > 
> > > i've a question about these two functions. My aim is to modify these
> > > benchmarks in order to create a trasmission system that can choose
> > > to put on a single carrier a BPSK or a QPSK modulation. My problem
> > > is this one, how can i comunicate to the receiver what carriers are
> > > BPSk adn what QPSK?
> > > 
> > > Thanks a lot
> > 
> > This is typically done by sending some kind of 'map' at the low rate
> > at the beginning of packet.  Take a look at WiMAX to see how
> > complicated this can get ;)
> > 
> > Eric

> I've seen it ;) but i've problem too even if i konw what carriers
> are BPSK and what are QPSK. I've studied how to modify ofdm.py in
> order to transmitt for example the first 10 signals with BPSK
> modulation and tre other with QPSK, but when i want to demodulate, i
> don't know which point of gr_ofdm_frame_sink.cc i must modify to
> demodulate correctly. Do you think my project is possible actually
> in gnuradio OFDM?

Sure it's possible.  You'll have to do some work.

Eric