[srslte-users] srsenb disconnection problem

[Nicola Bui]

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@
>> 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@
>>>> 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@
>>>>>> 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@
>>>>>>>>> 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
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>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>
>>>>
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