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

Robert Falkenberg robert.falkenberg at srs.io
Thu Sep 1 11:37:54 UTC 2022


Hi Cristina,

this is independent from the RF frontend.

Best regards,
Robert

On 01.09.22 13:34, Cristina Posada wrote:
>  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 list
>>     srsran-users at lists.srsran.com
>>     https://lists.srsran.com/mailman/listinfo/srsran-users
>
>     -- 
>
>
>           RobertFalkenberg
>
>     Senior Engineer
>
>     Software Radio Systems
>
>     	
>     	
>     	
>     	
>
>     	robert at srs.io <mailto:robert at srs.io>
>
>     	www.srs.io <//www.srs.io>
>
>     	Dortmund, Germany
>
>
>
>
>     	
>     twitter <https://twitter.com/srssystems> 	
>
>     _______________________________________________
>     srsran-users mailing list
>     srsran-users at lists.srsran.com
>     https://lists.srsran.com/mailman/listinfo/srsran-users
>

-- 


      RobertFalkenberg

Senior Engineer

Software Radio Systems

	

	
	

	

	robert at srs.io <mailto:robert at srs.io>

	www.srs.io <//www.srs.io>

	Dortmund, Germany




	
twitter <https://twitter.com/srssystems> 	
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