[srsran-users] UE disconnecting SA when another PRACH is created

Cristina Posada posadacristinacg at gmail.com
Thu Sep 1 11:34:36 UTC 2022 

 Thank you very much for your answer Robert!

I already have the activity timer set to : rrc_inactivity_timer = 1073741823
And I always keep the connection busy by pinging the UE...

Could this behavior be solved by using an USRP X310? Or is it just an UE
problem...?

Thank you again!

Best Regards,
Cris

El jue, 1 sept 2022 a las 13:13, Robert Falkenberg (<
robert.falkenberg at srs.io>) escribió:

> Hi Cristina,
>
> this is expected behavior at the moment:
>
> Re: [srsran-users] srsran 22.04 - 5G SA on UHD B210 hardware
>
> Hi Bas,
>
> glad you got that working now.
>
> On 24/5/22 16:07, Vermeulen, Bas (Consultant) wrote:
>
> I do occasionally see the following:
>
> ​PDU Session Establishment successful. IP: 10.45.0.2
>                                    │Disconnecting rnti=0x460a.
> RRC NR reconfiguration successful.
>                                   │RACH:  slot=3851, cc=0, preamble=0,
> offset=1, temp_crnti=0x460b
> qScheduling request failed: releasing RRC connection...
>                                 │Disconnecting rnti=0x460b.
>
>
>
> I am afraid that is expected. The UE is very basic and some of the
> procedures in RRC connected and idle aren't implemented.
>
> What you can try is to increase the inactivity timer in the eNB so the UE
> isn't released too soon.
>
> Thanks
> Andre
>
>
> Another option is to keep the connection busy, e.g. via "ping".
>
> Best regards,
> Robert
>
> On 31.08.22 11:43, Cristina Posada wrote:
>
> Hello all!!
>
> Following the 5G SA COTS UE Application Note
> <https://docs.srsran.com/en/latest/app_notes/source/5g_sa_COTS/source/index.html>,
> after running srsENB the UE successfully connects to the network and gets
> an assigned IP and access to the internet.
> But after a few seconds or minutes the UE disconnects from the network.
>
> Setup Details
>
>    - Operation System: Ubuntu 20.04
>    - srsRAN (last version)
>    - RF: USRP B210 (UHD driver)
>    - Asus ZenBook intel Core i7
>    - UE: Galaxy S21 FE 5G Sysmocom USIM
>    - Third Party 5G Core: Open5GS
>
> The B210 is connected to a GPS antenna (clock= GPSDO in enb.config file)
> The B210 is connected to external power and usb3.0. The laptop is also
> connected to power-source.
> The CPU governor of the PC is set to performance mode.
>
> enb output:
>
> [2022-08-31 11:18:08.018597711] Active RF plugins: libsrsran_rf_uhd.so libsrsran_rf_blade.so libsrsran_rf_zmq.so
> [2022-08-31 11:18:08.019614233] Inactive RF plugins:
> [2022-08-31 11:18:08.020493476] ---  Software Radio Systems LTE eNodeB  ---
> [2022-08-31 11:18:08.021239493]
> [2022-08-31 11:18:08.022201553] Reading configuration file enb.conf...
> [2022-08-31 11:18:08.047178857]
> [2022-08-31 11:18:08.048211004] Built in Release mode using commit ce8a3cae1 on branch master.
> [2022-08-31 11:18:08.049021063]
> [2022-08-31 11:18:08.112477909] Opening 1 channels in RF device=default with args=clock=gpsdo, master_clock_rate=11.52e6, sampling_rate=11.52e6, recv_frame_size=1024
> [INFO] [UHD] linux; GNU C++ version 9.4.0; Boost_107100; UHD_4.2.0.0-0ubuntu1~focal1
> [INFO] [LOGGING] Fastpath logging disabled at runtime.
> [2022-08-31 11:18:08.115658911] Supported RF device list: UHD bladeRF zmq file
> [2022-08-31 11:18:08.116465257] Trying to open RF device 'UHD'
> [2022-08-31 11:18:08.117174866] NG connection successful
> [INFO] [UHD RF] RF UHD Generic instance constructed
> [INFO] [B200] Detected Device: B210
> [INFO] [B200] Operating over USB 3.
> [INFO] [B200] Detecting internal GPSDO....
> [INFO] [GPS] Found an internal GPSDO: GPSTCXO , Firmware Rev 0.929a
> [WARNING] [B200] The recv_frame_size must be a multiple of 8 bytes and not a multiple of 1024 bytes.  Requested recv_frame_size of 1024 coerced to 1032.
> [INFO] [B200] Initialize CODEC control...
> [INFO] [B200] Initialize Radio control...
> [INFO] [B200] Performing register loopback test...
> [INFO] [B200] Register loopback test passed
> [INFO] [B200] Performing register loopback test...
> [INFO] [B200] Register loopback test passed
> [INFO] [B200] Asking for clock rate 11.520000 MHz...
> [INFO] [B200] Actually got clock rate 11.520000 MHz.
> [INFO] [MULTI_USRP]     1) catch time transition at pps edge
> [INFO] [MULTI_USRP]     2) set times next pps (synchronously)
> [2022-08-31 11:18:12.400379533] Opening USRP channels=1, args: master_clock_rate=11.52e6,recv_frame_size=1024,type=b200
> [2022-08-31 11:18:12.401261562] Setting USRP time to 1661937491.000000s
> [2022-08-31 11:18:12.401982356] RF device 'UHD' successfully opened
> [2022-08-31 11:18:12.402970691]
> [2022-08-31 11:18:12.403735479] ==== eNodeB started ===
> [2022-08-31 11:18:12.404528414] Type <t> to view trace
> [2022-08-31 11:18:12.405181947] Setting frequency: DL=2655.0 Mhz, DL_SSB=2654.55 Mhz (SSB-ARFCN=530910), UL=2535.0 MHz for cc_idx=0 nof_prb=52[2022-08-31 11:18:18.733662587] RACH:  slot=5931, cc=0, preamble=4, offset=9, temp_crnti=0x4601[2022-08-31 11:*18:36.973965842*] RACH:  slot=3691, cc=0, preamble=2, offset=1396, temp_crnti=0x4602[2022-08-31 11:18:37.072352755] Disconnecting rnti=0x4602.
> [2022-08-31 11:18:37.133436504] RACH:  slot=3851, cc=0, preamble=6, offset=1396, temp_crnti=0x4603
> [2022-08-31 11:18:37.232712131] Disconnecting rnti=0x4603.
> [2022-08-31 11:18:37.294178507] RACH:  slot=4011, cc=0, preamble=0, offset=1396, temp_crnti=0x4604
> [2022-08-31 11:18:37.393293625] Disconnecting rnti=0x4604.
> [2022-08-31 11:18:37.453494272] RACH:  slot=4171, cc=0, preamble=3, offset=1396, temp_crnti=0x4605
> [2022-08-31 11:18:37.552344813] Disconnecting rnti=0x4605.
> [2022-08-31 11:18:37.613804855] RACH:  slot=4331, cc=0, preamble=2, offset=1396, temp_crnti=0x4606
> [2022-08-31 11:18:37.712304317] Disconnecting rnti=0x4606.
> [2022-08-31 11:18:37.773490691] RACH:  slot=4491, cc=0, preamble=3, offset=1396, temp_crnti=0x4607
> [2022-08-31 11:18:37.872352053] Disconnecting rnti=0x4607.
> [2022-08-31 11:18:38.093870308] RACH:  slot=4811, cc=0, preamble=1, offset=9, temp_crnti=0x4608
> [2022-08-31 11:18:38.113321926] User 0x4608 requesting RRC Reestablishment as 0x4601. Cause: otherFailure
> [2022-08-31 11:18:38.114768882] Disconnecting rnti=0x4601.
> [2022-08-31 11:18:38.253817518] RACH:  slot=4971, cc=0, preamble=7, offset=9, temp_crnti=0x4609
> [2022-08-31 11:18:38.264462015] Disconnecting rnti=0x4609.
> [2022-08-31 11:18:38.573896896] RACH:  slot=5291, cc=0, preamble=3, offset=9, temp_crnti=0x460a
> [2022-08-31 11:18:38.672338152] Disconnecting rnti=0x460a.
> [2022-08-31 11:18:38.733493021] RACH:  slot=5451, cc=0, preamble=4, offset=9, temp_crnti=0x460b
> [2022-08-31 11:18:38.744443571] User 0x460b requesting RRC Reestablishment as 0x4608. Cause: reconfigurationFailure
> [2022-08-31 11:18:38.745617181] Disconnecting rnti=0x4608.
> [2022-08-31 11:18:38.893586462] RACH:  slot=5611, cc=0, preamble=0, offset=9, temp_crnti=0x460c
> [2022-08-31 11:18:38.992729952] Disconnecting rnti=0x460c.
>
> The UE disconnects when the second RACH arrives, or vice versa,  Another
> PRACH is created because the UE disconnects, but why does the UE disconnect?
>
> At enb.log we can see the PRACH:
>
> 2022-08-31T09:18:36.969264 [PHY1-NR] [I] [ 3688] PUCCH: f=1 prb=51:1
> symb=0:14 cs=8 occ=0 rnti=0x4601 sr=1 epre=-19.5 snr=-11.0 cfo=+694.8
> delay=+10.5 val>
> 2022-08-31T09:*18:36.972352* [PHY-NR ] [I] [    0] PRACH: cc=0, 0/1,
> preamble=2, offset=727.5 us, peak2avg=147.3, max_offset=1000.0 us
> 2022-08-31T09:18:36.972490 [MAC-NR ] [I] [ 3691] SCHED: rnti=0x4602, new
> lcid configuration: [{lcid=0, mode=bi-dir, prio=1, lcg=0}]
> 2022-08-31T09:18:36.972553 [RLC-NR ] [I] Added LTE radio bearer with LCID
> 0 in Transparent Mode
> 2022-08-31T09:18:36.972557 [RRC-NR ] [I] Added new user rnti=0x4602
> 2022-08-31T09:18:36.972557 [MAC-NR ] [I] [ 3691] RACH:  slot=3691, cc=0,
> preamble=2, offset=1396, temp_crnti=0x4602
> 2022-08-31T09:18:36.972565 [MAC-NR ] [I] [ 3691] rach_tprof: {mean, max,
> min}={247.1, 281, 212} usec, nof_samples=2
> 2022-08-31T09:18:36.973223 [MAC-NR ] [I] [ 3692] SCHED: New user
> rnti=0x4602, cc=0
> 2022-08-31T09:18:36.973224 [MAC-NR ] [I] [ 3692] SCHED: New PRACH
> slot=3691, preamble=2, ra-rnti=0xf, temp_crnti=0x4602, ta_cmd=1396,
> msg3_size=7
> 2022-08-31T09:18:36.973256 [MAC-NR ] [I] [ 3692] SCHED: RAR, cc=0,
> ra-rnti=0xf, prbs=[1, 5), pdsch_slot=3696, msg3_slot=3702, nof_grants=1
> 2022-08-31T09:18:36.973263 [MAC-NR ] [I] [ 3692] Setting RAR Grant
> tc-rnti=0x4602 dci=RAR ss=rar hop=0 f_alloc=0x68 t_alloc=0x0 mcs=0 tpc=1
> csi=0
> 2022-08-31T09:18:36.973267 [MAC-NR ] [I] [ 3692] DL RAPID: 2, Temp C-RNTI:
> 0x4602, TA: 1396, UL Grant: [00 d0 00 40 ]
> 2022-08-31T09:18:36.973292 [PHY1-NR] [I] [ 3692] PDCCH: cc=0
> ra-rnti=0x000f dci=1_0 ss=common1 L=2 cce=0 f_alloc=0x90 t_alloc=0x0
> vrb_to_prb_map=0 mcs=5 t>
> 2022-08-31T09:18:36.973322 [PHY1-NR] [I] [ 3692] PDSCH: cc=0 ra-rnti=0xf
> prb=(1,4) symb=(1,13) CW0: mod=QPSK tbs=44 R=0.383 rv=0  tti_tx=3696
> 2022-08-31T09:18:36.977211 [PHY1-NR] [I] [ 3696] PDCCH: cc=0
> si-rnti=0xffff dci=1_0 ss=common0 L=2 cce=0 f_alloc=0x150 t_alloc=0x0
> vrb_to_prb_map=0 mcs=5 >
> 2022-08-31T09:18:36.977249 [PHY1-NR] [I] [ 3696] PDSCH: cc=0
> si-rnti=0xffff prb=(1,8) symb=(2,13) CW0: mod=QPSK tbs=80 R=0.380 rv=0
>  tti_tx=3700
> 2022-08-31T09:18:36.983317 [PHY1-NR] [I] [ 3702] PUSCH: tc-rnti=0x4602
> prb=(0,2) symb=(0,13) CW0: mod=QPSK tbs=11 R=0.131 rv=0 CRC=KO iter=10.0
> evm=0.74 t>
> 2022-08-31T09:18:36.983335 [MAC-NR ] [I] [ 3702] SCHED: UL retx, cc=0,
> rnti=0x4602, pid=0, cs=0, f=0_0, nrtx=1, tbs=11, bs=0, pusch_slot=3710
>
> Before, it shows the message:
>
> 2022-08-31T09:*18:30.916264* [MAC-NR ] [I] [ 7875] SCHED: discarding
> rnti=0x4601, DL TB pid=0. Cause: Maximum number of retx exceeded (4)
>
>
> *Sometimes it is connected for 20 minutes and others for just a few
> seconds... *
>
>
> I have also tried srsRAN in *LTE* mode and I didn't have this problem,
> the *connection lasts forever.*
>
> I attach the config files and enb.log
>
> Also.. How can I check my antenna and make sure the UL is stable?
>
> Thank you very much!!
>
> BR,
> Cris
>
>
>
>
>
> _______________________________________________
> srsran-users mailing listsrsran-users at lists.srsran.comhttps://lists.srsran.com/mailman/listinfo/srsran-users
>
>
> --
> Robert Falkenberg
>
> Senior Engineer
>
> Software Radio Systems
>
>
>
> robert at srs.io
> www.srs.io <//www.srs.io>
> Dortmund, Germany
>
>
>
> [image: twitter] <https://twitter.com/srssystems>
>
> _______________________________________________
> srsran-users mailing list
> srsran-users at lists.srsran.com
> https://lists.srsran.com/mailman/listinfo/srsran-users
>
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