OFDM benchmark USRP padding

Hello everyone,

I noticed that in the OFDM benchmark implementation, the padding for
the USRP is set to false in transmit_path.py when creating the ofdm
modulator, whereas in the digital/benchmark it is set to true.

I do not see where else in the OFDM implementation the packets to be
sent through the USB are set to be 512 bytes. Is this not strictly
necessary? Could anyone help me with that?

Thanks!

Natalia Olano