Re: [Discuss-gnuradio] OFDM_TX_RX

[Marcus Müller]

Dear Farid,

please always respond on the mailing list.
Thank you,
Marcus Müller

On Sat, 2019-05-25 at 17:36 +0100, farid mihoub wrote:
> 1- For the noise : in the TX side the output is in the order of 2A,
> the noise 0.05A.
> 2-Second even without noise, the const does not affect the
> transmission, is there any sort of power normalization?
> 3-For the FEC and the modulation I want to try my custom mapping
> where information is linearly related to complex symbols, and my
> application doesn't require error correction.  
>  
> Thank you.
> 
> 
> 25.05.2019, 17:06, "Marcus Müller" <address@hidden>:
> > Hello Farid,
> > On Sat, 2019-05-25 at 15:59 +0100, farid mihoub wrote:
> > >  Hello,
> > > 
> > >  In the OFDM_tx, rx examples in gr-digital :
> > >  1- Why just a low level of noise affect the transmission and
> > > cause it
> > >  to stop.
> > 
> > "low" is relative. It seems it's high enough to cause packet
> > losses,
> > iff it's actually the noise.
> > 
> > >  2- in the the Tx output and the Rx input no matter the value of
> > > the
> > >  multiply constant we apply
> > >     that would not affect our transmission.
> > 
> > Then it's probably not only the noise!
> > 
> > >  3- Is there any way to separate channel estimation and tracking
> > > from
> > >     data transmission, sometime I get the error "invalid packet
> > >  detected!" form the packet parser, also I need my data to bypass
> > > FEC
> > >  and QAM.
> > 
> > Um, prior to QAM demodulation there is no data, and prior to FEC
> > decoding there is no information bits, so I'm not sure what you
> > want?
> > 
> > >     My purpose is to stream raw complex data to the I/Q
> > > components
> > >  directly.
> > 
> > Then it seems you don't want an OFDM transceiver but maybe just
> > simply
> > a single IFFT? Not quite sure what you have in mind.
> > 
> > Best regards,
> > Marcus
> >