[srslte-users] srsLTE on Ettus E310

Tue Apr 7 18:56:56 UTC 2015

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 at 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 at 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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>>>>>>>
>>>>>>
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