Ok, so you send 25 cycles, the first few of those cycles are always undetectable by the receiver - I don't see how the receiver can derive from this how many cycles have passed that it didn't detect. - you have a nice strong signal to do phase detection on, but you still don't know which of the 25 cycles is which by the time they reach the receiver.
i.e. (the following diagram does not include the time of flight, just to make things easier :))
Sender: ------_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_---------
Receiver: ----------_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-----
^^^^ ^^^^
Undetectable due to low amplitude Ringing after the sender has finished
Am I missing something?