srsENB connection not stable with 22.10

[bigbossolidsnake]

Issue Description

HI srsRAN development team,

I have already looked at the srsRAN users mailing list and noted that another user is also facing the similar issue as mine. I am using Build 22.10 of srsRAN 4G. I am having trouble maintaining a stable attach with the UE. Knowing that my RF front-end might have unstable internal clock and as noted here, i have supplied a very stable 10 MHz external frequency reference to it, and i have verified that the front end is able to lock on to this external frequency reference.

I have collected logs and packet capture which i am attaching with this post for your further expert assessment and evaluation. The attached logs show multiple times this attach attempt is made.

[Describe the issue in detail]

Setup Details

OS: Ubuntu 22.04 Hardware: Intel® Xeon(R) CPU E5-1607 v3 @ 3.10GHz × 4 with 36.0 GiB of Memory RF Front End: LimeSDR USB connected over USB 3.0 to the computer hardware above. srsRAN Version: 22.10 Driver: Soapy SDR driver. Version: I can find this out if need be.

Expected Behavior

Connection to remain stable after attach.

Actual Behaviour

srsenb and UE have an unstable connection, restart attach procedure.

==== eNodeB started === Type to view trace Setting frequency: DL=2680.0 Mhz, UL=2560.0 MHz for cc_idx=0 nof_prb=50 RACH: tti=8601, cc=0, pci=1, preamble=37, offset=12, temp_crnti=0x46 RACH: tti=9991, cc=0, pci=1, preamble=11, offset=12, temp_crnti=0x47 Disconnecting rnti=0x47. RACH: tti=10101, cc=0, pci=1, preamble=12, offset=12, temp_crnti=0x48 Disconnecting rnti=0x48. RACH: tti=10221, cc=0, pci=1, preamble=1, offset=12, temp_crnti=0x49 Disconnecting rnti=0x49. RACH: tti=101, cc=0, pci=1, preamble=43, offset=12, temp_crnti=0x4a Disconnecting rnti=0x4a. RACH: tti=221, cc=0, pci=1, preamble=22, offset=12, temp_crnti=0x4b Disconnecting rnti=0x4b. RACH: tti=341, cc=0, pci=1, preamble=6, offset=12, temp_crnti=0x4c Disconnecting rnti=0x4c. RACH: tti=461, cc=0, pci=1, preamble=19, offset=12, temp_crnti=0x4d Disconnecting rnti=0x4d. User 0x46 connected RACH: tti=2931, cc=0, pci=1, preamble=16, offset=12, temp_crnti=0x4e Disconnecting rnti=0x4e. RACH: tti=3021, cc=0, pci=1, preamble=43, offset=12, temp_crnti=0x4f Disconnecting rnti=0x4f. RACH: tti=3111, cc=0, pci=1, preamble=27, offset=12, temp_crnti=0x50 Disconnecting rnti=0x50. RACH: tti=3201, cc=0, pci=1, preamble=17, offset=12, temp_crnti=0x51 Disconnecting rnti=0x51. RACH: tti=3291, cc=0, pci=1, preamble=38, offset=12, temp_crnti=0x52 Disconnecting rnti=0x52. RACH: tti=3381, cc=0, pci=1, preamble=12, offset=12, temp_crnti=0x53 Disconnecting rnti=0x53. RACH: tti=3471, cc=0, pci=1, preamble=37, offset=12, temp_crnti=0x54 Disconnecting rnti=0x54. RACH: tti=4261, cc=0, pci=1, preamble=27, offset=12, temp_crnti=0x55 Disconnecting rnti=0x46. RACH: tti=5791, cc=0, pci=1, preamble=14, offset=12, temp_crnti=0x56 Disconnecting rnti=0x56. User 0x55 connected RACH: tti=5931, cc=0, pci=1, preamble=30, offset=12, temp_crnti=0x57 Disconnecting rnti=0x57. RACH: tti=7311, cc=0, pci=1, preamble=22, offset=12, temp_crnti=0x58 Disconnecting rnti=0x58. User 0x55 connected RACH: tti=7451, cc=0, pci=1, preamble=20, offset=12, temp_crnti=0x59 Disconnecting rnti=0x59. RACH: tti=7551, cc=0, pci=1, preamble=41, offset=12, temp_crnti=0x5a Disconnecting rnti=0x5a. RACH: tti=8211, cc=0, pci=1, preamble=21, offset=12, temp_crnti=0x5b Disconnecting rnti=0x5b. RACH: tti=8391, cc=0, pci=1, preamble=13, offset=12, temp_crnti=0x5c Disconnecting rnti=0x55. RACH: tti=10191, cc=0, pci=1, preamble=36, offset=12, temp_crnti=0x5d Disconnecting rnti=0x5d. User 0x5c connected

Steps to reproduce the problem

1. Build srsRAN 22.10 with Soapy Driver so that LimeSDR USB can work
2. Make sure LimeSDR USB driver is installed
3. Make necessary edits to your your ue.conf file for authentication details
4. Start srsepc
5. Start srsenb

Additional Information

Attaching the logs , config files and mac_pcap with this email. Let me know if you need any other info. Note that this issue doesn't manifest with earlier build of srsRAN such as 22.04.1 with the same RF front end(Lime SDR USB) with or without external clock reference.

Logs_Configs_PCAP.zip

[ismagom]

To diagnose these kind of issues, better to attach logs in info mode. Other than that, I can see there are many retx at RLC level, which indicates a bad signal quality. You need to try to improve that.