QPSK modulation with Relay


We just received 2 USRP mother boards, and 4 RFX2400 boards with 4 vert
antennas, I have installed them and connected with two separate PCs (os
ubuntu 8.04). I installed all the required packages

I did benchmark_tx and rx and siggen.py and got same results as
explained in given documents on gnuradi.org.

I tried to look for qpsk implementation but I couldn’t understand well
how to start with.

Can somebody explain me step by step which files I have to use. I got
little idea but I am not very much sure.

I want to perform qpsk first 1X1, 1X2 and 1 tx, 2 relays, 1 rx.

I want to describe some problems also:

1- I have connected both of Tx/Rx (of two flex 2400) port with vert
antennas, which side is A and which side is B.
2- If I fire one Tx/Rx from 1 pc (usrp_siggen.py or usrp_benchmark_tx -f
2440M -T A or B) and try to receive on the 2nd pc (usrp_oscope.py or
usrp_fft.py) at the same time same computer using two linux terminals.
It shows reception only on one terminal on others it show couldn’t find

Appreciate your answers.

Thanks in advance!