[Discuss-gnuradio] Full Duplex operation, time synchronization and self interference cancellation

[Pranav Padalkar]

Hello all,

I am trying to design a full duplex operation on my USRP3. I have to use OFDM and a defined TDMA scheme for different OFDM symbols. I also have to use a preamble, but it has to be sent once every TDMA frame. I have designed a block which takes care of my TDMA and preamble implementation. Basically, I cannot use packet structure (as given in the OFDM examples). On the transmitter side I am using OFDM carrier allocator, IFFT and OFDM cyclic prefixer(CP). 

Since, it has to be full duplex system, on the receiver side I want to perform the synchronization of my received signal with the transmitted signal, and then after removing CP and performing FFT, I have to subtract my received signal from the transmitted signal. I tried to understand the corr_est and corr_sync blocks by going through their examples. But I am not able to understand how can I get the value of offset (after synchronization), so that using that offset value I can shift my TX signal and subtract the RX signal.

I request if some one can point me in the right direction.

Thanks and Regards,

Pranav Padalkar

Fraunhofer-Institut für Eingebettete Systeme und Kommunikationstechnik ESK