[srslte-users] srsenb disconnection problem

Tue Oct 31 19:15:49 UTC 2017

Right now, I changed band: I was using band 8 (950MHz) because it is ISM in
the US, but now I am using band 7 and, apparently, I don't see the issue
any longer.
Before eob today I will get the srsue/srsenb case tested in band 8 and band
7 and I will tell you about the outcome.
However, if band 7 is working, I think I have a starting point.

Best,

Nicola Bui
Senior Research Scientist
College of Computer and Information Science
655E Interdisciplinary Science and Engineering Complex
Boston, MA 02115

On Tue, Oct 31, 2017 at 3:11 PM, Ismael Gomez <
ismael.gomez at softwareradiosystems.com> wrote:

> Can you run the same with srsUE and srsENB and send us both ue.log and
> enb.log please? That would be more helpful I think.
>
> I have uhd 3.9.2 and use B210. That would be the best platform.
>
> What other phones have you tried and you couldn't connect? We have used
> huawei dongles and phones, nexus 4 and 5, etc and never find any issue..
>
> On Tue, 31 Oct 2017 at 10:12 Nicola Bui <n.bui at northeastern.edu> wrote:
>
>> Hi,
>>
>> I tried with two different USRP B210 and different antennas. I never
>> tried with a reference signal, not sure I can. I am trying with a different
>> phone, but so far only the moto g5+ could see the network.
>> The thing is the problem happened also if I tried connecting srsue to
>> srsenb. Now I am also trying with a different version of the uhd driver
>> (which version do you suggest?)
>> I can also try with bladeRF if you believe it might be better.
>> Just let me know which configuration has the highest chance of working.
>>
>> Thanks,
>>
>> Nicola Bui
>> Senior Research Scientist
>> College of Computer and Information Science
>> 655E Interdisciplinary Science and Engineering Complex
>> Boston, MA 02115
>>
>> On Tue, Oct 31, 2017 at 10:58 AM, Ismael Gomez <ismael.gomez@
>> softwareradiosystems.com> wrote:
>>
>>> Now that's the same issue you saw with 25 PRB. For some reason it looks
>>> like the USRP stops transmitting for a short period of time or the UE
>>> disconnects. From the logs it looks like all is normal and good so I'm not
>>> sure what could be happening.
>>>
>>> If you have access to another USRP, could you try swapping it? Are you
>>> using B210? Do you have a GPSDO or 10 MHz reference signal? Can you try
>>> with another phone?
>>>
>>> On Tue, 31 Oct 2017 at 06:35 Nicola Bui <n.bui at northeastern.edu> wrote:
>>>
>>>> Hi Ismael, all,
>>>>
>>>> the disconnection issue happened without an hardware fault as well (no
>>>> warning late, underflow, overflow).
>>>> Please find attached a log showing it.
>>>>
>>>> Best,
>>>>
>>>> Nicola Bui
>>>> Senior Research Scientist
>>>> College of Computer and Information Science
>>>> 655E Interdisciplinary Science and Engineering Complex
>>>> Boston, MA 02115
>>>>
>>>> On Mon, Oct 30, 2017 at 2:02 PM, Ismael Gomez <ismael.gomez@
>>>> softwareradiosystems.com> wrote:
>>>>
>>>>> 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@
>>>>>> 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@
>>>>>>>> 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 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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