Evgeny: I just updated the wiki. If you are willing to test them out, please try the new GR3.8 tutorials under the subsection "Using BPSK with Hardware Simulation (version 3.8)" https://wiki.gnuradio.org/index.php/Packet_Communications
On Wed, Nov 10, 2021 at 12:07 PM Evgeny Hahamovich <evgym...@gmail.com> wrote: > Hi Paul, > > I tried to perform a similar experiment and unfortunately after investing > a significant effort, still haven't figured out how the packets method > works :( > For now, I pack the data in python, send the packed data to GNURadio and > LimeSDR_Tx. and on the Rx side, I detect by LimeSDR_Rx, perform all the > clock recovery procedure in GNURadio and then send the extracted *bits* > to python via ZeroMQ where I do the unpacking with my code. It's definitely > not optimal, but it works. > > Evgeny > > > On Wed, Nov 10, 2021 at 5:16 PM Paul Martin <m4rti...@gmail.com> wrote: > >> Hi! >> >> I'm trying to send a file through a LimeSDR mini with a loopback cable >> using PSK modulation. >> >> >> The gr-limesdr plugin only works with gnuradio 3.8, so I'm on that >> version. >> >> OS is Linux Mint 20.2: >> $ cat /proc/version >> Linux version 5.11.0-37-generic (buildd@lcy01-amd64-021) (gcc (Ubuntu >> 9.3.0-17ubuntu1~20.04) 9.3.0, GNU ld (GNU Binutils for Ubuntu) 2.34) >> #41~20.04.2-Ubuntu SMP Fri Sep 24 09:06:38 UTC 2021 >> >> CPU: 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz >> >> >> The examples that I could find all used the deprecated packet >> encoder/decoder, so I set up to adapt the packet_loopback_hier example, >> which relies on packet_tx and packet_rx (documentation here >> https://www.gnuradio.org/doc/doxygen/page_packet_comms.html). >> >> My flowgraph is here: >> >> grc packet_loopback_hier.grc https://pastebin.com/w1cQxTLJ >> >> screen capture packet_loopback_hier.png https://imgur.com/wccyfwC >> >> (modified from >> https://github.com/gnuradio/gnuradio/blob/maint-3.8/gr-digital/examples/packet/packet_loopback_hier.grc >> ). >> >> The packet_tx and packet_rx are here: >> >> packet_tx.grc https://pastebin.com/fhqQ1Y4n >> >> packet_rx.grc https://pastebin.com/Zvr3x7vK >> >> (these are exactly the ones from the repo >> https://github.com/gnuradio/gnuradio/blob/maint-3.8/gr-digital/examples/packet/packet_tx.grc >> https://github.com/gnuradio/gnuradio/blob/maint-3.8/gr-digital/examples/packet/packet_rx.grc >> ). >> >> >> At first, I removed the channel model and got it working with a file >> source and sink, albeit with some limitations: >> The file needs to be "small" or I get a buffer overflow error (I'm using >> an ~8 KiB file, attached), and I had to pad the byte amount of the file to >> be an integer number of the packet_len, plus an additional full packet >> (I've attached the sample file that I'm using, input_file_padded.dat >> https://drive.google.com/file/d/1f3Os_okrn-d-DJrm0L1CyEKUxnOS_TDE/view?usp=sharing). >> These limitations don't bother me so I didn't look for the cause, I'm just >> mentioning them in case they are relevant. >> >> Then I added the LimeSDR source and sink, but I don't get any data at the >> output of Packet Rx. Looking at the constellations at output out of Packet >> Tx (left) and the LimeSDR source (right) I get this (constellations.png >> https://imgur.com/a/vGz4sHO). >> >> From what I could research, the left constellation isn't the four dots >> that I initially expected because of the RRC filter. >> On the right constellation, I have no clue if what I'm seeing makes sense. >> >> >> Before moving forward and investigating why the different blocks of >> Packet Rx aren't outputting anything, I'm trying to make sure that the >> received signal is correct. >> >> >> I've also made a video of the flowgraph running ( >> https://imgur.com/a/opY6dV9): on the first GUI sink from the left is the >> correlation estimator output, then the output of Packet Tx, LimeSDR source, >> and Packet Rx; and attached the console output (packet_loopback_hier.txt >> https://pastebin.com/r3ivn4eq). >> >> >> Summarizing: Is the output of the LimeSDR source right or am I doing >> something wrong? >> >> >> Thanks for taking the time to read my question! >> >> Regards, >> Paul >> > >
