[srslte-users] srsLTE on Ettus E310

[Ismael Gomez]

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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