Unstable network with USRP B200

[alinstoica19]

Issue Description

I followed the instructions from the COTS UE practical application and UE cannot stay connected for a long time to srsenb, there are fluctuations, meaning it disconnects and reconnects often.

Setup Details

Operation System: Ubuntu 22.04 UHD version: 4.1 RF front-end: USRP B200

Expected Behavior

I expect the UE to be stable at srsenb without disconnecting and reconnecting.

Actual Behaviour

This is the srsenb output: RACH: tti=3631, cc=0, pci=1, preamble=50, offset=0, temp_crnti=0x126 RACH: tti=3651, cc=0, pci=1, preamble=29, offset=0, temp_crnti=0x127 Disconnecting rnti=0x127. Disconnecting rnti=0x126. RACH: tti=3731, cc=0, pci=1, preamble=32, offset=1, temp_crnti=0x128 Disconnecting rnti=0x128. RACH: tti=3811, cc=0, pci=1, preamble=40, offset=1, temp_crnti=0x129 Disconnecting rnti=0x129. RACH: tti=3891, cc=0, pci=1, preamble=20, offset=1, temp_crnti=0x12a Disconnecting rnti=0x12a. RACH: tti=3971, cc=0, pci=1, preamble=36, offset=0, temp_crnti=0x12b Disconnecting rnti=0x12b. RACH: tti=4081, cc=0, pci=1, preamble=23, offset=0, temp_crnti=0x12c Disconnecting rnti=0x12c. RACH: tti=4161, cc=0, pci=1, preamble=3, offset=0, temp_crnti=0x12d Disconnecting rnti=0x12d. RACH: tti=4241, cc=0, pci=1, preamble=3, offset=0, temp_crnti=0x12e Disconnecting rnti=0x12e. RACH: tti=4321, cc=0, pci=1, preamble=44, offset=0, temp_crnti=0x12f Disconnecting rnti=0x12f. RACH: tti=4401, cc=0, pci=1, preamble=16, offset=0, temp_crnti=0x130 Disconnecting rnti=0x130. RACH: tti=4501, cc=0, pci=1, preamble=51, offset=1, temp_crnti=0x131 User 0x131 requesting RRC Reestablishment as 0x125. Cause: otherFailure Disconnecting rnti=0x125. User 0x131 connected and so on..

And the srsepc output:

HSS Initialized.

MME S11 Initialized MME GTP-C Initialized MME Initialized. MCC: 0xf001, MNC: 0xff01 SPGW GTP-U Initialized. SPGW S11 Initialized. SP-GW Initialized. Received S1 Setup Request. S1 Setup Request - eNB Name: srsenb01, eNB id: 0x19b S1 Setup Request - MCC:001, MNC:01 S1 Setup Request - TAC 7, B-PLMN 0xf110 S1 Setup Request - Paging DRX v128 Sending S1 Setup Response Initial UE message: LIBLTE_MME_MSG_TYPE_ATTACH_REQUEST Received Initial UE message -- Attach Request Attach request -- M-TMSI: 0x9f559da Attach request -- eNB-UE S1AP Id: 1 Attach request -- Attach type: 2 Attach Request -- UE Network Capabilities EEA: 11110000 Attach Request -- UE Network Capabilities EIA: 11110000 Attach Request -- MS Network Capabilities Present: true PDN Connectivity Request -- EPS Bearer Identity requested: 0 PDN Connectivity Request -- Procedure Transaction Id: 23 PDN Connectivity Request -- ESM Information Transfer requested: false UL NAS: Received Identity Response ID Response -- IMSI: 001010123456780 Downlink NAS: Sent Authentication Request UL NAS: Received Authentication Response Authentication Response -- IMSI 001010123456780 UE Authentication Accepted. Generating KeNB with UL NAS COUNT: 0 Downlink NAS: Sending NAS Security Mode Command. UL NAS: Received Security Mode Complete Security Mode Command Complete -- IMSI: 001010123456780 Getting subscription information -- QCI 7 Sending Create Session Request. Creating Session Response -- IMSI: 1010123456780 Creating Session Response -- MME control TEID: 1 Received GTP-C PDU. Message type: GTPC_MSG_TYPE_CREATE_SESSION_REQUEST SPGW: Allocated Ctrl TEID 1 SPGW: Allocated User TEID 1 SPGW: Allocate UE IP 172.16.0.2 Received Create Session Response Create Session Response -- SPGW control TEID 1 Create Session Response -- SPGW S1-U Address: 127.0.1.100 SPGW Allocated IP 172.16.0.2 to IMSI 001010123456780 Adding attach accept to Initial Context Setup Request Sent Initial Context Setup Request. E-RAB id 5 Received Initial Context Setup Response E-RAB Context Setup. E-RAB id 5 E-RAB Context -- eNB TEID 0x1; eNB GTP-U Address 127.0.1.1 UL NAS: Received Attach Complete Unpacked Attached Complete Message. IMSI 1010123456780 Unpacked Activate Default EPS Bearer message. EPS Bearer id 5 Received GTP-C PDU. Message type: GTPC_MSG_TYPE_MODIFY_BEARER_REQUEST Sending EMM Information Initial UE message: NAS Message Type Unknown Received Initial UE message -- Service Request Service request -- S-TMSI 0xe5a71c5f Service request -- eNB UE S1AP Id 2 Service Request -- Short MAC valid There are active E-RABs, send release access bearers request Received GTP-C PDU. Message type: GTPC_MSG_TYPE_RELEASE_ACCESS_BEARERS_REQUEST Service Request -- User is ECM DISCONNECTED UE previously assigned IP: 172.16.0.2 Generating KeNB with UL NAS COUNT: 11 UE Ctr TEID 0 Sent Initial Context Setup Request. E-RAB id 5 Received UE Context Release Complete. MME-UE S1AP Id 1 No UE context to release found. MME-UE S1AP Id: 1 Found UE for Downlink Notification MME Ctr TEID 0x1, IMSI: 001010123456780 Received Initial Context Setup Response E-RAB Context Setup. E-RAB id 5 E-RAB Context -- eNB TEID 0x2; eNB GTP-U Address 127.0.1.1 Initial Context Setup Response triggered from Service Request. Sending Modify Bearer Request. Received GTP-C PDU. Message type: GTPC_MSG_TYPE_MODIFY_BEARER_REQUEST Modify Bearer Request received after Downling Data Notification was sent T3413 expired -- Could not page the ue. Received GTP-C PDU. Message type: GTPC_MSG_TYPE_DOWNLINK_DATA_NOTIFICATION_FAILURE_INDICATION Initial UE message: LIBLTE_MME_MSG_TYPE_TRACKING_AREA_UPDATE_REQUEST Received Initial UE message -- Tracking Area Update Request Tracking Area Update Request -- S-TMSI 0xe5a71c5f Tracking Area Update Request -- eNB UE S1AP Id 3 Warning: Tracking area update requests are not handled yet. Initial UE message: LIBLTE_MME_MSG_TYPE_ATTACH_REQUEST Received Initial UE message -- Attach Request Attach request -- M-TMSI: 0xe5a71c5f Attach request -- eNB-UE S1AP Id: 4 Attach request -- Attach type: 2 Attach Request -- UE Network Capabilities EEA: 11110000 Attach Request -- UE Network Capabilities EIA: 11110000 Attach Request -- MS Network Capabilities Present: true PDN Connectivity Request -- EPS Bearer Identity requested: 0 PDN Connectivity Request -- Procedure Transaction Id: 31 PDN Connectivity Request -- ESM Information Transfer requested: false Attach Request -- Found previously attach UE. Found UE context. IMSI: 001010123456780, old eNB UE S1ap Id 2, old MME UE S1AP Id 2 Received GUTI-Attach Request from attached user. There are active E-RABs, send release access bearers request Received GTP-C PDU. Message type: GTPC_MSG_TYPE_DELETE_SESSION_REQUEST GUTI Attach request NAS integrity failed. RE-starting authentication procedure. Downlink NAS: Sent Authentication Request Received UE Context Release Complete. MME-UE S1AP Id 2 No UE context to release found. MME-UE S1AP Id: 2 UL NAS: Received Authentication Response Authentication Response -- IMSI 001010123456780 UE Authentication Accepted. Generating KeNB with UL NAS COUNT: 0 Downlink NAS: Sending NAS Security Mode Command. UL NAS: Received Security Mode Complete Security Mode Command Complete -- IMSI: 001010123456780 Getting subscription information -- QCI 7 Sending Create Session Request. Creating Session Response -- IMSI: 1010123456780 Creating Session Response -- MME control TEID: 2 Received GTP-C PDU. Message type: GTPC_MSG_TYPE_CREATE_SESSION_REQUEST SPGW: Allocated Ctrl TEID 2 SPGW: Allocated User TEID 2 SPGW: Allocate UE IP 172.16.0.3 Received Create Session Response Create Session Response -- SPGW control TEID 2 Create Session Response -- SPGW S1-U Address: 127.0.1.100 SPGW Allocated IP 172.16.0.3 to IMSI 001010123456780 Adding attach accept to Initial Context Setup Request Sent Initial Context Setup Request. E-RAB id 5 Received Initial Context Setup Response E-RAB Context Setup. E-RAB id 5 E-RAB Context -- eNB TEID 0x3; eNB GTP-U Address 127.0.1.1 UL NAS: Detach Request Detach request -- IMSI 001010123456780

Steps to reproduce the problem

Run srsepc and then srsenb, use the right USIM and find the network which you have just instantiated using srsRAN 4G.

Additional Information

I only use an antenna that I have on TX/RX. The logs from /tmp do not show any unusual behavior.

[yagoda]

Hi,

Can you share the logs, please?

Regards, JUstin

[alinstoica19]

Sure, these are logs: enb.log epc.log

[yagoda]

Can you please enable all log levels to "info"

[alinstoica19]

All log levels for epc are already set to info( all_level = info). srsepc log Here is the output for enb with log levels to info:
srsenb log