Hello,
I am working on the implementation of OFDM TX and RX using USRP
N210 and GNURadio.
I used the the grc flow graphs done by GNURadio workshops and I
was able to receive the OFDM signal and demodulate it.
Also, I connected a constellation sink to the Palyoad Stream
Virtual Source at the RX side (after demodulation), and I got 4
constellation points which is corresponding
to the QPSK similar to the Tx cosntellation.
However, when I removed the Smidl and Cox synchronization to
check the phase rotation from the CFO (please see attached) , I
still have the same 4 constellation points without phase
rotation. Do you know why this happens?
You haven't described your physical setup, but if you have TX
looped-back to RX, there won't be any phase rotation since