Thanks for trying, Martin. My OFDM Specs are:
FFT size = 64 CP length = 16 bandwidth = 2KHz carrier freq: centered around 2.437GHz It is easier to reproduce if I replace the noise block with one that adds CFO errors. a) Increase this CFO error until header CRCs fail. Let this stand for a few seconds. b) Reduce CFO offset errors to 0. c) Go to step a and repeat a few times. I observe that after doing this a few times, the RX path freezes up. In any case, thank you very much for trying to reproduce this error. I really appreciate your help. :) best regards, aditya On Thu, Jan 16, 2014 at 10:11 AM, Martin Braun <martin.br...@ettus.com>wrote: > On Wed, Jan 15, 2014 at 07:55:45PM -0500, Aditya Dhananjay wrote: > > There is a variant of this issue that I discovered and would like to > point > > it out to the community. > > > > Synopsis: After the first time the header CRC fails, *all* subsequent > > packets fail. > > > > Setup: > > > > - GRC examples of Tx/Rx OFDM > > - Noise source with a variable slider to control the amount of noise. The > > output of the Tx block is added with the output of the noise source. > > - The output of this adder is connected to the Rx block. > > > > Procedure: > > > > - Start the experiment with 0 noise. We see that the packets are > > successfully decoded. > > - Increase the noise, and we observe that the packet success rate begins > to > > drop (payload CRC failures) > > - Further increase the noise to force a header CRC failure. > > - Decrease the noise back to 0. Notice that the packet success rate > remains > > 0, even though the noise is 0. > > > > This is highly repeatable. Any help would be greatly appreciated. > > Hm, can't repeat it. I used the loopback example. Increasing noise does > make packets drop (as expected), but setting it back makes them come > again. A noise amplitude of ~2 causes most packets to fail, but some > come through. What are your OFDM specs? > > MB > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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