This is why cell phones use different uplink/downlink frequencies (or time slots). Are you using two different USRP ports for TX and RX and connecting them to the same antenna? Or are you using a TX/RX port with tx and rx streamers attached?
On Tue, Aug 18, 2020 at 11:48 AM Cameron Matson via USRP-users < [email protected]> wrote: > Hey everyone, > > I've copied both the gnuradio and usrp lists, since I'm not sure if the > question has a software or hardware answer, so I apologize for duplicate > emails. > > I am attempting to set up a wireless transceiver using N310s and the > packet tx/rx examples from gnuradio. I combined both the tx and rx chains > in one flowgraph with zeromq source/sink blocks like this: > > [zmq source] -> [packet tx] -> [usrp sink] > and > [usrp source] -> [packet rx] -> [zmq sink] > > I have a separate python file running in a separate process. That handles > messages from the zmq blocks and controls state changes between "backoff", > "listen" and "talk" > > I'm not sure the specific terminology for the variety of duplex I'm trying > to implement, but I want the TX and RX to happen on the same frequency > using one antenna. The problem is that if I use the same frequency, my RX > chain immediately "hears" the signal that was transmitted. By "hears" I > mean that the first part of the [packet rx] block, which is the > [correlation estimator] block detects the signal as a valid packet. The > problem is that because the amplitude of my desired rx signal is low, I've > had to set the threshold of the correlation estimator relatively low--and > so the recently transmitted signal, which has a much higher amplitude being > right next to the rx antenna, overwhelms the detector. This doesn't happen > if I have the TX and RX on different frequencies > > What I don't quite fully understand is what happens on the N310 when a > flow graph with both transmit and receive processes are active. I can see > from the LEDs that it is "receiving" most of the time and when it gets a > message to transmit it will blink to tx and then back. What happens in > this process? One thought is that since its the same antenna, the tx and > rx might share a buffer and the tx data is still present there. > > Is what I'm trying to do even possible? > > Thanks for your time, > > Cameron > _______________________________________________ > USRP-users mailing list > [email protected] > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >
