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OAI UE stalls at Msg3

OAI UE stall at Msg3 if it sends a Msg3 with MAC CE for C-RNTI and the RNTI is not identified in gNB:

[NR_PHY]   [RAPROC] 504.7 Initiating RA procedure with preamble 23, energy 37.4 dB (I0 233, thres 140), delay 5 start symbol 0 freq index 0
[NR_MAC]   504.7 UE RA-RNTI 0063 TC-RNTI f1ae: Activating RA process index 0
[NR_MAC]   UE f1ae: Msg3 scheduled at 505.7 (505.1 TDA 0)
[NR_MAC]   UE f1ae: 505.1 Generating RA-Msg2 DCI, RA RNTI 0x63, state 1, preamble_index(RAPID) 23, timing_offset = 5 (estimated distance 390.6 [m])
[NR_MAC]   505.1 Send RAR to RA-RNTI 0063
[NR_MAC]   Adding new UE context with RNTI 0xf1ae
[NR_MAC]    505. 7 PUSCH with TC_RNTI 0xf1ae received correctly
[NR_MAC]   Received a MAC CE for C-RNTI with a38a
[NR_MAC]   No UE found with C-RNTI a38a, ignoring Msg3 to have UE come back with new RA attempt

UE stalls here:

[PHY]   PRACH [UE 0] in frame.slot 504.7, placing PRACH in position 728, Msg1/MsgA-Preamble frequency start 0 (k1 0), preamble_offset 4, first_nonzero_root_idx 0, preambleIndex = 23
[NR_MAC]   [UE 0][RAPROC][RA-RNTI 0005] Got BI RAR subPDU 99 ms
[NR_MAC]   [UE 0][RAPROC][RA-RNTI 0063] Got RAPID RAR subPDU
[NR_MAC]   [UE 0][RAPROC][505.1] Found RAR with the intended RAPID 23
[MAC]   received TA command 36
[PHY]   RAR-Msg2 decoded
[NR_MAC]   [RAPROC][505.7] RA-Msg3 transmitted

Steps to reproduce:

  • Start gNB with USRP
  • Start OAI UE with USRP
  • wait until PDUSession establishes
  • Stop gNB
  • Start gNB
  • OAI UE will sync again and trigger new RA
  • OAI UE will stall at Msg3