I was able to send four bursts between two USRP2s. The two USRP2s were
equipped with xcvr2450 boards. The bursts were 0.336ms long. The spacing
between the bursts were 3ms. The sample rate was 25MHz. The four bursts
were sent as A->B, B->A, A->B, B->A. The nodes were locked to (the same)
10MHz reference and a pps trigger. The boards were connected by cable.
The very nice thing was that the channel seen in the two A->B bursts
were the same (including absolute phase, timings etc.). The same applies
to the two B->A bursts. This opens up many possibilities.