Scheduling request failed: releasing RRC connection

[Zplusless]

I set up a testbed with two USRP-B210s (with external GPSDO 10MHz clock) following the toturial srsRAN gNB with srsUE — srsRAN Project documentation. The two USRP-B210s are connected with SMA cable. The srsran_performance script is executed on both server.

However, the connection is not stable. The srsUE often fails to work after several seconds' continues working with iperf. The error is as follows:

edge@EDGE:~/srs-config$ ./run_ue.external.sh
[sudo] password for edge:
Active RF plugins: libsrsran_rf_uhd.so
Inactive RF plugins:
Reading configuration file ue_lab.cn.external.conf...

Built in Release mode using commit fa56836b1 on branch master.

Opening 1 channels in RF device=uhd with args=clock= external
Supported RF device list: UHD file
[INFO] [UHD] linux; GNU C++ version 11.4.0; Boost_107400; UHD_4.5.0.HEAD-0-g471af98f
[INFO] [LOGGING] Fastpath logging disabled at runtime.
Opening USRP channels=1, args: type=b200,master_clock_rate=23.04e6
[INFO] [UHD RF] RF UHD Generic instance constructed
[INFO] [B200] Detected Device: B210
[INFO] [B200] Operating over USB 3.
[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 23.040000 MHz...
[INFO] [B200] Actually got clock rate 23.040000 MHz.
Setting manual TX/RX offset to 300 samples
Waiting PHY to initialize ... done!
Attaching UE...
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=6734
Random Access Complete.     c-rnti=0x4601, ta=0
RRC Connected
PDU Session Establishment successful. IP: 10.45.0.14
RRC NR reconfiguration successful.

RF status: O=0, U=1, L=0
Scheduling request failed: releasing RRC connection...
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=4014
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=4174
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=4334
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=4494
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=4654
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=4814
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=4974
Scheduling request failed: releasing RRC connection...
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=6574
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=6734
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=6894
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=7054
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=7214
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=7374
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0x39, tti=7534

My configs:

gnb_local_cn_external.yml.txt
ue_lab.cn.external.conf.txt
gnb server: Intel(R) Xeon(R) D-1747NTE CPU @ 2.50GHz, 10 cores 20 threads
ue server: Intel(R) Core(TM) i5-10500 CPU @ 3.10GHz, 6 cores 12 threads

logs:

https://drive.google.com/drive/folders/1BM-ufJg5DzqDE5Bl6Y1v0iN3Q8k_akf8?usp=sharing

[brendan-mcauliffe]

Hi @Zplusless based on your other open discussion point, I am assuming you have solved this issue? If so can you let me know so I can close this point.

[herlesupreeth]

Can you elaborate whether the issue was resolved or not? And another thing, please use the latest code from main branch so that if this is a bug it may have been resolved

I would suggest to test the gain as follows in gNB config file

  tx_gain: 80                                                   # Transmit gain of the RF might need to adjusted to the given situation.
  rx_gain: 40                                                   # Receive gain of the RF might need to adjusted to the given situation. 

also in UE config file (comment out rx_gain and increase tx_gain)

tx_gain = 80
#rx_gain = 40

Also, in your UE console output I see the following, which could be due to incorrect time_adv_nsamples value.

[Zplusless]

Didn't notice that the master branch has been updated. I'll try the latest code. Thanks.

[pgawlowicz]

@Zplusless did the new release solve the issue?

[Zplusless]

We are now working on zmq mode. I will test the latest version on UDH mode next week.

[Zplusless]

Sorry, there are some problems with our usrp-b210. The UHD mode could not be tested temporarily.

[Zplusless]

Should I add parameters like:

max_nof_prb = 106
nof_prb = 106

in config file of UE? These are used in UE 20MHz config, but result in UE attachment failure with 10MHz.

[herlesupreeth]

No, those are only for 20Mhz. I will take a look at the logs and get back to you

[Zplusless]

Thanks!

[pgawlowicz]

@Zplusless can we close here?

[Zplusless]

Sorry, I'm not sure wheter the problem is solved. Our USRP has malfunctioned and cannot be used for testing

[pgawlowicz]

no problem, let us know once you can test it again.