I have implemented a packet reception and transmission scheme using QPSK. Next I decided to add Polar/LDPC encoding. As a result, nothing is written to the received file. I think the thing is that I'm unpacking the bits incorrectly after demodulation. For convenience, in the diagram, I highlighted packet formation and encoding in blue, and decoding and unpacking in red. enter image description here I've tried many different versions of Repack Bits, not one has helped.

A similar problem exists for LDPC.

Please tell me how to properly unpack the bits after demodulation?

P.S. If I remove the signal modulation, then the flowchart will work (i.e. if I leave only the blue and red rectangle).

P.S.S. As I understood Polar and LDPC encoding works with MSB bits. Unfortunately, this is not explicitly stated on the Gnu Radio website.

  • $\begingroup$ hi! Asking three questions in 30 minutes might be a bit … much. $\endgroup$ Apr 17, 2023 at 15:47
  • $\begingroup$ @MarcusMüller Hi. I just tried to solve these problems on my own about two weeks, but I reached the limit at which I don't understand where to go next. Therefore, the questions accumulated and I posted them. $\endgroup$
    – Ice Cool
    Apr 17, 2023 at 15:49
  • $\begingroup$ Welcome, in any case :) It's absolutely welcome that you ask questions. It's just that I wanted to warn you that the number of people that have time to go through them is quite limited, and it might take some time till we read all three. $\endgroup$ Apr 17, 2023 at 15:51
  • $\begingroup$ @MarcusMüller, Yes, I understand that. Moreover, my questions are quite highly specialized and even a small hint is already good. $\endgroup$
    – Ice Cool
    Apr 17, 2023 at 15:58
  • $\begingroup$ can i ask what is the output file when stream crc32 is set to check crc $\endgroup$
    – qqqqqz
    May 26, 2023 at 2:38


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