[srslte-users] srsLTE on Ettus E310

Wed Apr 8 10:03:03 UTC 2015

Hi Tom,

Thank you for doing all these tests.

So apparently in terms of functionality the processing is fine in the
E310.  The MIB is not shown when you read from the file because the MIB
decoding is skipped. I think that the problem could precisely be in the MIB
decoding. That would explain why usrp_capture_sync fails at "Waiting for
SFN=0".

I modified the pdsch_ue and usrp_capture_sync. Now usrp_capture_sync does
not perform MIB decoding and just gets synchronized frames (all 10
subframes).

The new pdsch_ue performs MIB decoding. So, can you please try again with
the same commands than before? If I'm not wrong, the pdsch_ue should now
fail at MIB decoding. If that happens, you won't see anything at all.

Please run the pdsch_ue with the "-vv" argument and send me the log.

Thank you.

Ismael

On Tue, 7 Apr 2015 at 19:57 Tom Chatt <tom.j.chatt at gmail.com> wrote:

> Hi Ismael,
>
> I rebuilt the srsLTE project on my PC and tried running the instructions
> you gave.  I am able to capture and then decode a signal using
> ./usrp_capture_sync and then ./pdsch_ue using my PC and USRP-B200.
> However, I am not able to run the usrp_capture_sync program on the E310.
>  ./usrp_capture_sync reaches the stage of "Waiting for SFN=0" and then
> hangs indefinitely.  I tried copying the data file I captured with my
> PC/B200 to the E310 and running pdsch_ue, and the E310 reported 0% PDCCH
> miss and PDSCH-BLER.  So, that implies to me that there might be a timing
> problem with data acquisition on the E310.  Any thoughts on what else I
> should try?
>
> Also - should I be seeing a printout of the MIB / cell information when I
> run pdsch_ue on file data? I see one when I run it on streaming data, but
> not from a file.  If not, is there an option to enable it?
>
> --Tom
>
> On Mon, Apr 6, 2015 at 4:07 AM, Ismael Gomez <ismael.gomez@
> softwareradiosystems.com> wrote:
>
>> Hi Tom,
>>
>> Yesterday I pushed to the repository the changes that allow capturing a
>> synchronized signal into a file and run the receiver on it.
>>
>> To capture a file, cd to srslte/examples and run:
>> ./usrp_capture_sync -f [freq] -l [N_id_2] -p [nof_prb] -g [rx_gain] -n
>> 10240 -o [output_file_name]
>>
>> Where nof_prb and N_id_2 are for the signal you want to capture.
>> (N_id_2=cell_id%3).
>>
>> Then run the following to pass this file through the receiver:
>>
>> ./pdsch_ue -i [input_file_name] -p [nof_prb] -P [nof_ports] -c [cell_id]
>>
>> where again nof_prb, nof_ports and cell_id from the cell you want to scan
>> must be known.
>>
>> Let me know what you see. Thanks!
>>
>>
>> On Thu, 2 Apr 2015 at 19:08 Ismael Gomez <ismael.gomez@
>> softwareradiosystems.com> wrote:
>>
>>> No it doesnt. It assumes the signal in the file starts at subframe #0
>>>
>>> On Thu, 2 Apr 2015 18:55 Tom Chatt <tom.j.chatt at gmail.com> wrote:
>>>
>>>> Thanks for looking into this for me.  With regards to step #1/2....I
>>>> recorded data to a file, and I do have the Matlab LTE toolbox, so I am able
>>>> to synchronize the file.  However, does this mean that the "file read mode"
>>>> doesn't do any synchronization of its own?
>>>>
>>>> On Thu, Apr 2, 2015 at 4:06 AM, Ismael Gomez <ismael.gomez@
>>>> softwareradiosystems.com> wrote:
>>>>
>>>>> Yes it is possible. You have to do the following:
>>>>>
>>>>> 1) Record a file, e.g. using uhd_rx_cfile (default complex format)
>>>>> 2) Synchronise the file, so that the first sample is the first sample
>>>>> of subframe 0. You can do this with the Matlab LTE toolbox if you have it,
>>>>> or with the sync/test/pss_mex.c file. If CMake finds Matlab/Octave, this
>>>>> file creates a MEX file srslte_pss() which has the same interface than the
>>>>> LTE toolbox and returns the offset to subframe 0.
>>>>> I'll try to create a program to do this more automatically today or
>>>>> tomorrow.
>>>>> 3) Use pdsch_ue example replacing argument "-f [freq]" by "-i
>>>>> [file_name] -p [nof_prb] " and editing lines 306 and 310 in
>>>>> srslte/examples/pdsch_ue.c with your cell. I'll also change it
>>>>> today/tomorrow to allow passing these as parameters.
>>>>>
>>>>> I'll post to the list when these changes are ready.
>>>>>
>>>>> On Wed, 1 Apr 2015 at 20:40 Tom Chatt <tom.j.chatt at gmail.com> wrote:
>>>>>
>>>>>> I should mention that all the "O" messages occur at the beginning of
>>>>>> the process, and none took place once the program had hung.  I just ran
>>>>>> make test and all tests passed.  Is it possible to run srsLTE with data
>>>>>> from a file, instead of "live" signal data from the USRP?  If so, I could
>>>>>> try recording data from the USRP B200 connected to my PC and play it back
>>>>>> on the E310, to try to see if it's a timing issue or some other kind of bug.
>>>>>>
>>>>>> When you say that the pos=1545 indicates that synchronization is
>>>>>> correct - are you referring to PSS / SSS sync?
>>>>>>
>>>>>> On Wed, Apr 1, 2015 at 4:07 AM, Ismael Gomez <ismael.gomez@
>>>>>> softwareradiosystems.com> wrote:
>>>>>>
>>>>>>> So you said that exactly the same software version and with the same
>>>>>>> program arguments runs fine in a desktop PC but not in the E310. That must
>>>>>>> be some timing issue or a bug that is only seen with the ARM compiler (e.g.
>>>>>>> uninitialized variable).
>>>>>>>
>>>>>>> The "O" messages indicate timing issues, but they don't seem to be a
>>>>>>> problem if there are only 4 in 10 minutes and the pos=1545 is always the
>>>>>>> same. That indicates that synchronization is correct.
>>>>>>>
>>>>>>> Can you run make test and let me know if all tests are completed
>>>>>>> successfully?
>>>>>>>
>>>>>>> Thanks
>>>>>>>
>>>>>>> On Tue, 31 Mar 2015 at 20:13 Tom Chatt <tom.j.chatt at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Apologies if this doesn't show up in the correct thread; I'm new to this listserv and didn't have digest mode disabled, so I didn't have an email to reply to.
>>>>>>>>
>>>>>>>>
>>>>>>>> >Can you check if the pos=1545 is repeated in all messages? If not that
>>>>>>>> >would mean that sync is lost, probably because the ARM9 can not process
>>>>>>>> >fast enough.
>>>>>>>>
>>>>>>>> pos= changes early on, but pos=1545 is repeated in all messages after a short time.
>>>>>>>>
>>>>>>>>
>>>>>>>> >Have you compiled srsLTE in the ARM9 with VOLK support?
>>>>>>>>
>>>>>>>> srsLTE is compiled with Volk support (neon_hardfp_orc)
>>>>>>>>
>>>>>>>> >Also, can you run it without -v and see if you see "O" messages on the
>>>>>>>> >console output? You should see them on the left of the screen.
>>>>>>>>
>>>>>>>> A total of 4 "O" messages showed up after letting it run for ~10 minutes.
>>>>>>>>
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