File transfer through USRP

Hi,

I’m a newbie to this area and trying to transfer file through USRP.
I’ve read some documentation and tutorial about how FM receiver works
on USRP. However, file transfer seems not that easy since the receiver
must to notify when the file start and end. Also, I’m not sure how to
turn binary 0 and 1 (or even ASCII) to FSK/PSK mode and then could be
sent by the device. Could anyone give some information or links to
step out the first pace? Thanks very much.

Yours,
Yuankai