Everyone who implements half duplex modems runs into this issue sooner or later. A simple fix is to catch this in software, e.g. On your Mac layer by filtering for your own transmit Mac address (or whatever equivalent you have in your protocol). You can also cache the timestamps of your tx packets and use that to ignore rx packets.
Cheers Martin On 26 Feb 2016 07:25, "Marcus D. Leech" <mle...@ripnet.com> wrote: > On 02/26/2016 07:00 AM, Alex Weihkopf wrote: > > Hello, > > I am using two USRP2 + WBX connected via cable on the TX/RX antenna > ports. I want to use them for my GNURadio OFDM-project in half-duplex mode. > > *Problem*: Whenever I send a data-packet (~10ms) on the TX-chain of one > USRP2, I receive the same packet on the RX-chain of the same USRP2. The > transmitter receives its own packets. > > Why is that? Insufficient Decoupling between Receive and Transmit Circuit? > > Does the USRP2 internally turn off the Receive Circuit when the Transmit > Circuit has data to send? Or does it just disconnect the Receive Circuit > from the antenna? > > Is there a comprehensible GNURadio example for USRP2 + WBX > in half-duplex-mode? > > Regards, > Alex > > > > > The RX chain is not disabled, only switched-away from the TX/RX antenna. > There's about 40+dB of isolation between the two sides, > but that still produces a fair amount of signal at the RX. The best way > forward is to simply ignore RX traffic while you're TXing. > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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