srsue synchronization issues with SA Amarisoft Callbox

[kbaccar]

Issue Description

I have been trying to make a 5G SA connection between srsue and the amarisoft callbox following the tutorial on the wiki page. Im using an SDR B210 and without a GPSDO the connection seems completely random as sometimes it stops at the RA procedure or at most I manage to just get an RRC connection for it to get released afterward with a scheduling request error. After installing a GPSDO (tcxo from ettus) on the SDR, setting clock=external would give me completely nothing and the SDR fails to send any message to the callbox. I only managed to get a PDU session with clock=gpsdo but the connection is still nonetheless unstable as i lose synchronization immediately after trying an iperf test.

Setup Details

srsue machine: ubuntu 20.04., srsue 22.4, UHD 3.15. Amarisoft callbox: lteots-linux-2022-03-19, usrp B210 connected on sdr1 on rx1 and tx1 with -30 db attenuators.

enb.txt ue.txt

[andrepuschmann]

Hey, can you share log files and console output for the UE in info mode please?

[kbaccar]

Hello @andrepuschmann, this is after initating an iperf test

/build/srsran-j7rCyf/srsran-22.04/lib/src/phy/rf/rf_uhd_imp.cc:833: Could not lock reference clock source. Sensor: gps_locked=false
RF device 'UHD' successfully opened
Invalid length for IMEI: 0 should be 15
Waiting PHY to initialize ... done!
Attaching UE...
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0xf, tti=3371
Random Access Complete.     c-rnti=0x4605, ta=3
RRC Connected
RRC NR reconfiguration successful.
PDU Session Establishment successful. IP: 192.168.2.2
RRC NR reconfiguration successful.
RF status: O=0, U=5, L=54
Scheduling request failed: releasing RRC connection...
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0xf, tti=3531
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0xf, tti=3691
RF status: O=0, U=1, L=0
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0xf, tti=3851
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0xf, tti=4011
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0xf, tti=4171
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0xf, tti=4331
Random Access Transmission: prach_occasion=0, preamble_index=0, ra-rnti=0xf, tti=4491

ue.log

[andrepuschmann]

The lates your seeing (RF status: O=0, U=5, L=54) causes the UE to loose sync and it then can't resync again. It's a known limitation I am afraid.

[TallGuy74]

@kbaccar Are you running iperf3 on the client with zerocopy (-Z) enabled? It makes a huge difference on the CPU use of iperf, and may be enough to get rid of the late packets. Also, make sure you have the CPU governor to performance with echo performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor.

[IndrawanBudiP]

The lates your seeing (RF status: O=0, U=5, L=54) causes the UE to loose sync and it then can't resync again. It's a known limitation I am afraid.

Hi, if something happen like that. So what should I do to make it sync again