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Re: [Discuss-gnuradio] transmitter receiving its own packet


From: Marcus D. Leech
Subject: Re: [Discuss-gnuradio] transmitter receiving its own packet
Date: Tue, 09 Apr 2013 15:36:28 -0400
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This seems like a common scenario and it seems like it would make sense to push the behaviour as low as possible in the stack. Is there a configuration parameter for the USRP "device driver" that instructs the driver to drop self routed signals?


It could do that, and I'll let Josh comment on how awkward it would be for UHD to arrange to do that.

But the RX and TX chains on the hardware are essentially entirely-independant units, with no cross-unit semantic implied anywhere in the hardware
  (except for antenna switching).

The problem of "downloading" operational semantics into hardware that should be as "semantic free" as possible is that it adds to:

    o FPGA bloat
    o loss of generality

And while I agree *this particular semantic* may be justified, in some circumstances, it's a slippery slope. One might argue that 'nFSK' is such a common requirement, it should be done at very low layers, or, 'OFDM' or whatever else is popular this week. That turns the hardware, and the software stack above it, into not so much an SDR, as an SCR, with pre-defined purposes.

Furthermore, if you want to make the hardware implement part of your operational semantic, you're free to do that in the FPGA code yourself. The codebase is freely available, and there's room in the FPGAs of the various USRP devices to do tweaks like that.



--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org





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