[srslte-users] srsenb disconnection problem

Sat Oct 28 23:50:03 UTC 2017

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
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>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>
>>>
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