On 12 Dec 2013, at 15:26, Nasi [email protected] wrote:
Yes, I receive hopefully. But the packer error rate is too high. I went through
different configurations and gains. And finally I see that the problem is the
transmission side. The gain does not have any influence on the error rate.
Just to be sure: do you have the current version? (some weeks ago I
normalized the signal power to 1 without pushing updates of the flow
graphs. That lead to distorted signals. In that case, changing the gain
does not help.)
Can you please be a litte bit more verbose? Where do you plug in the FFT sink?
What do you see? What did you expect to see.
Yes, sure. So I attach FFT sink to the USRP source in the ofdm_rx.grc. You
should see an FFT plot like a normal FFT block. I set FFT size to 64 and frequency
to the frequency which I transmit or receive. Ok. lets say we do not care what we
see, but when I change the gain in the transmitter nothing changes in the plot.
You know that the curve dB should go higher, isn’t it? However in this case the
receiver signal dB is below -80 dB which showa that there is very low signal.
Even I detach the antenna it works, funnily. I testet this with benchmarks to
see if it is a hardware problem or not. It seems like smt. is wrong in the
transmission side. Do you have any idea what can cause it?
Thanks, I guess the problem is that just very few samples of your
incoming stream belong to WiFi frames. So chances are that the frame is
not visualised at all (I think that the FTT sink uses a subset of the
samples based on the sample rate and the update rate of the GUI). If you
really want to stick to this approach I would recommend to checkout
gr-fosphor. I found it really helpful.