[srslte-users] srsenb disconnection problem

Mon Oct 30 18:02:15 UTC 2017

Hi Nicola,

I think this is a different issue than the one for 25 PRB, despite the
result is the same. I've opened an issue in gtihub at
https://github.com/srsLTE/srsLTE/issues/111. Could you please follow up
with your results there?

I've created a new branch that I think could fix the issue. I've pushed it
to:

https://github.com/srsLTE/srsLTE/tree/fix_issue_111

Can you please test it?

thanks

On Mon, 30 Oct 2017 at 09:47 Nicola Bui <n.bui at northeastern.edu> wrote:

> I tried a few more times and this time I noticed the following message
> 12:30:56.148357 [RRC ] Warning User rnti=0x46 expired Activity deadline:
> -1:-146192054>60:0 us
> it seems like I have a problem with the deadlines (why the ms deadline is
> 0?) and the use of tv variables (why negative?)
> Can it be the cause of the disconnection?
>
>
> Nicola Bui
> Senior Research Scientist
> College of Computer and Information Science
> 655E Interdisciplinary Science and Engineering Complex
> Boston, MA 02115
>
> On Sun, Oct 29, 2017 at 12:02 AM, Ismael Gomez <
> ismael.gomez at softwareradiosystems.com> wrote:
>
>> Also, make sure you have the TX and RX antennas in cross polarization,
>> e.g. one vertical and the other horizontal to avoid tx/rx cross-talk.
>>
>> On Sat, 28 Oct 2017 at 16:52 Nicola Bui <n.bui at northeastern.edu> wrote:
>>
>>> Sure, as soon I'm back in the lab on Monday
>>>
>>>
>>> Nicola
>>>
>>> On Oct 28, 2017 19:50, "Ismael Gomez" <
>>> ismael.gomez at softwareradiosystems.com> wrote:
>>>
>>>> Yes, could you send me the log for 50 PRB please?
>>>> thanks
>>>>
>>>> El sáb., 28 oct. 2017 15:30, Nicola Bui <n.bui at northeastern.edu>
>>>> escribió:
>>>>
>>>>> Thanks. Please let me know if I can help in any way.
>>>>>
>>>>>
>>>>> Nicola
>>>>>
>>>>> On Oct 28, 2017 18:28, "Ismael Gomez" <
>>>>> ismael.gomez at softwareradiosystems.com> wrote:
>>>>>
>>>>>> Let me look into it and get back to you. We havent seen that issue in
>>>>>> our lab. We've done very high loads for hours without any random access or
>>>>>> losing the connection.
>>>>>>
>>>>>> El sáb., 28 oct. 2017 15:21, Nicola Bui <n.bui at northeastern.edu>
>>>>>> escribió:
>>>>>>
>>>>>>> CFI is always set to 3 and I already tried with 50 rb, with the same
>>>>>>> result: during high load the mobile performs a random access which succeeds
>>>>>>> and cause the misalignment between epc and enb.
>>>>>>> How can I get the cause of the "DCI can't be scheduled"?
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Nicola
>>>>>>>
>>>>>>>
>>>>>>> On Oct 28, 2017 18:17, "Ismael Gomez" <
>>>>>>> ismael.gomez at softwareradiosystems.com> wrote:
>>>>>>>
>>>>>>> Hi Nicola,
>>>>>>>
>>>>>>> I see you are using 25 PRB, what value you have for nof_ctrl_symbols
>>>>>>> in enb.conf? Can you try setting it to 3 if you haven't already? If you
>>>>>>> have, can you try with 50 PRB?
>>>>>>>
>>>>>>> In the logs it looks like the DCIs can't be scheduled. You can see
>>>>>>> log messages like this:
>>>>>>>
>>>>>>> 13:54:15.964584 [MAC ] Warning [05901] SCHED: Could not schedule DL
>>>>>>> DCI for rnti=0x46, pid=0
>>>>>>>
>>>>>>> You can also see that the eNodeB receives no PUCCH in messages like
>>>>>>> this:
>>>>>>>
>>>>>>> 13:54:15.965262 [PHY0] Info    [05898] PUCCH: rnti=0x46, corr=0.02,
>>>>>>> n_pucch=20, n_prb=1, ack=0
>>>>>>>
>>>>>>> Look at corr value, it must be at least >0.8. This is because the UE
>>>>>>> didn't receive the PDCCH grant and therefore is not sending the PUCCH ACK
>>>>>>> signal.
>>>>>>>
>>>>>>> We use a quite conservative scheduler for PDCCH and it might try to
>>>>>>> use highest aggregation level and it can't fit. I'll look into it, in the
>>>>>>> meantime, can you try with 50 PRB and send me the log again if you see the
>>>>>>> same issue?
>>>>>>>
>>>>>>> thanks
>>>>>>>
>>>>>>> On Fri, 27 Oct 2017 at 12:32 Nicola Bui <n.bui at northeastern.edu>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Another thing I just noticed is that the sequence of operations in
>>>>>>>> the phone is as follows:
>>>>>>>> - the phone is connected
>>>>>>>> unknown trigger
>>>>>>>> - the phone attempts a new random access
>>>>>>>> - the random access succeeds and the phone gets a new c-RNTI from
>>>>>>>> the eNB together with a new IP address
>>>>>>>> - the eNB disconnects the old c-RNTI
>>>>>>>> It looks to me that at this point the mobile phone is connected to
>>>>>>>> the eNB on a TEID that mismatch the one it is using in the EPC.
>>>>>>>> Is there a way to understand if a new random access procedure is
>>>>>>>> perfomed by a terminal considered already connected to the eNB?
>>>>>>>> Maybe I am just wrong.
>>>>>>>>
>>>>>>>> Looking forward to your interpretation.
>>>>>>>> Best,
>>>>>>>>
>>>>>>>>
>>>>>>>> Nicola Bui
>>>>>>>> Senior Research Scientist
>>>>>>>> College of Computer and Information Science
>>>>>>>> 655E Interdisciplinary Science and Engineering Complex
>>>>>>>> Boston, MA 02115
>>>>>>>>
>>>>>>>> On Fri, Oct 27, 2017 at 2:08 PM, Nicola Bui <n.bui at northeastern.edu
>>>>>>>> > wrote:
>>>>>>>>
>>>>>>>>> Hi Ismael,
>>>>>>>>>
>>>>>>>>> attached you can find the log. To get the error I did the
>>>>>>>>> following:
>>>>>>>>> - start the epc (OAI - hss, mme, spgw)
>>>>>>>>> - start srsenb
>>>>>>>>> - turn on the off
>>>>>>>>> - some pings to 172.16.0.1 to check the connectivity
>>>>>>>>> - speedtest (in the middle of the download test) the C-RNTI got
>>>>>>>>> released
>>>>>>>>> 13:54:16.034525 <0345%2025> [RRC ] Info    Disconnecting
>>>>>>>>> rnti=0x46.
>>>>>>>>> Before this, in the log you can find that there is another RRC
>>>>>>>>> connection request, which should not be there to the best of my knowledge.
>>>>>>>>> After the disconnection the mobile phone continue using the new
>>>>>>>>> C-RNTI obtained with the strange connection request, but, apparently, only
>>>>>>>>> the uplink is working.
>>>>>>>>>
>>>>>>>>> Please, let me know should you need other tests and thank you for
>>>>>>>>> the support.
>>>>>>>>> Best regards,
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Nicola Bui
>>>>>>>>> Senior Research Scientist
>>>>>>>>> College of Computer and Information Science
>>>>>>>>> 655E Interdisciplinary Science and Engineering Complex
>>>>>>>>> Boston, MA 02115
>>>>>>>>>
>>>>>>>>> On Fri, Oct 27, 2017 at 11:28 AM, Ismael Gomez <
>>>>>>>>> ismael.gomez at softwareradiosystems.com> wrote:
>>>>>>>>>
>>>>>>>>>> Hi nicola, can you send the enb.log?
>>>>>>>>>>
>>>>>>>>>> El vie., 27 oct. 2017 3:52, Nicola Bui <n.bui at northeastern.edu>
>>>>>>>>>> escribió:
>>>>>>>>>>
>>>>>>>>>>> Thanks Ishmael, Kewin,
>>>>>>>>>>>
>>>>>>>>>>> that's not my issue: the problem happens while the phone is
>>>>>>>>>>> active, in particular when the last is high.
>>>>>>>>>>> I already tried increasing the inactivity timer and the error
>>>>>>>>>>> count in the configuration file.
>>>>>>>>>>> The stranger thing is, as soon as the phone is disconnected (I
>>>>>>>>>>> believe it is the enb starting the disconnection) it gets a new rnti and,
>>>>>>>>>>> from the phone perspectives, the network is visible and connected. However,
>>>>>>>>>>> nothing works anymore like the new rnti is not linked anymore to the proper
>>>>>>>>>>> device in the epc.
>>>>>>>>>>> Instead, if I toggle the network from the phone, everything is
>>>>>>>>>>> resumed properly.
>>>>>>>>>>> I cannot send a log right now but I'll try to generate one
>>>>>>>>>>> containing the issue and send it to you.
>>>>>>>>>>>
>>>>>>>>>>> Best,
>>>>>>>>>>>
>>>>>>>>>>> Nicola
>>>>>>>>>>>
>>>>>>>>>>> On Oct 27, 2017 04:00, "Kewin Rausch" <krausch at fbk.eu> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Hi everyone,
>>>>>>>>>>>>
>>>>>>>>>>>> I had a similar issue (dunno if it's really the same), and I
>>>>>>>>>>>> partially resolved it by following Ismael answer and increasing the
>>>>>>>>>>>> inactivity timeout period (now I set it at 60 seconds).
>>>>>>>>>>>> Basically If i leave the UE connected to 4G but I do not
>>>>>>>>>>>> generate traffic (for about the time the inactivity timeout value), it get
>>>>>>>>>>>> disconnected by the eNB.
>>>>>>>>>>>>
>>>>>>>>>>>> This is not happening while I'm connected to a commercial base
>>>>>>>>>>>> station, which means that something nasty is happening, and maybe paging is
>>>>>>>>>>>> not correctly handled.
>>>>>>>>>>>>
>>>>>>>>>>>> I've tried the configuration with a Nexus 5, and once it get
>>>>>>>>>>>> disconnected I need to reset everything by switching on and off the
>>>>>>>>>>>> Airplane mode.
>>>>>>>>>>>>
>>>>>>>>>>>> Cheers,
>>>>>>>>>>>> Kewin
>>>>>>>>>>>>
>>>>>>>>>>>> On Fri, Oct 27, 2017 at 8:35 AM, Ismael Gomez <
>>>>>>>>>>>> ismael.gomez at softwareradiosystems.com> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>> Hi nicola, can you send us the enb.log? It is normal behavior
>>>>>>>>>>>>> to release the connection after inactivity. You can extend the timeout in
>>>>>>>>>>>>> the enb.conf file, expert section.
>>>>>>>>>>>>>
>>>>>>>>>>>>> However the UE should reconnect when paging is received when
>>>>>>>>>>>>> you ping it for instance. If you send me the log I can check it.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Regards
>>>>>>>>>>>>>
>>>>>>>>>>>>> El jue., 26 oct. 2017 17:27, Nicola Bui <
>>>>>>>>>>>>> n.bui at northeastern.edu> escribió:
>>>>>>>>>>>>>
>>>>>>>>>>>>>> Dear all,
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I am running srsenb using oai as EPC. My mobile phone (moto
>>>>>>>>>>>>>> g5+) connects to the network and for a while behave normally (ping is ok,
>>>>>>>>>>>>>> surfing is ok, speedtest is fine). However, after some time everything
>>>>>>>>>>>>>> stops working even though the phone still has an IP address the enb says
>>>>>>>>>>>>>> the UE is attached (c-RNTI assigned properly).
>>>>>>>>>>>>>> Actually, in the enb log I can see the c-RNTI got released
>>>>>>>>>>>>>> and a new one got assigned to the UE, but the new connection is not working
>>>>>>>>>>>>>> anymore. The only way for recovering the connectivity is from the mobile
>>>>>>>>>>>>>> toggling on and off the airplane mode.
>>>>>>>>>>>>>> The only error message I can see is: Unhandled feature in RRC
>>>>>>>>>>>>>> function: liblte_rrc_unpck_rrc_connection_setup_complete
>>>>>>>>>>>>>> However this appears even when the connection has been
>>>>>>>>>>>>>> properly setup.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> It will be great if I can get a more stable connection or if
>>>>>>>>>>>>>> the connection can be automatically reestablished.
>>>>>>>>>>>>>> Any suggestion on how to debug this?
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>> Nicola Bui
>>>>>>>>>>>>>> Senior Research Scientist
>>>>>>>>>>>>>> College of Computer and Information Science
>>>>>>>>>>>>>> 655E Interdisciplinary Science and Engineering Complex
>>>>>>>>>>>>>> Boston, MA 02115
>>>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>>>> srslte-users mailing list
>>>>>>>>>>>>>> srslte-users at lists.softwareradiosystems.com
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> http://www.softwareradiosystems.com/mailman/listinfo/srslte-users
>>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>>> srslte-users mailing list
>>>>>>>>>>>>> srslte-users at lists.softwareradiosystems.com
>>>>>>>>>>>>>
>>>>>>>>>>>>> http://www.softwareradiosystems.com/mailman/listinfo/srslte-users
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>
>>>>>>>
>
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