This clause describes necessary additions as compared to the case where network sharing with multiple cell-ID broadcast is not applied.
The signalling flows in the subsequent clauses assuming 2 sharing operators, A and B. The F1-C signalling transport deployment used is indicated within the subsequent clauses.
The gNB-DUB sends the F1AP INITIAL UL RRC MESSAGE to the gNB-CUB. including the NR CGI associated with PLMNB, the C-RNTI indicated by the gNB-DUA at step 2, and the RRC-Container IE and the RRC-Container-RRCSetupComplete IE with the RRC message received in step1 and step 5 respectively. The RRC-Container-RRCSetupComplete IE are included in the INITIAL UL RRC MESSAGE TRANSFER for the case of network sharing and shall contain the RRC messages received via the RRC UL-DCCH-Message IE from the UE, but never previously sent to the gNB-CUB.
Depicts the case where the UE context could not be retrieved by the new gNB-CUA. In step 2A, the NR CGI associated to PLMNA is indicated. In step 5A, the gNB-CUA would prepare the possibility to revert back to normal RRC Connection Establishment, indicating that the UE Context was not retrieveable and may include the re-directed RRC message as received in step 1. After step 5A, the gNB-DUA may redirect the UE towards the PLMN indicated in DL RRC MESSAGE TRANSFER message, if the PLMN assistance information is provided by the gNB-CUA. If the New gNB-DUA/B was not able to deduce the RRC message from step 1, this indicator triggers step 2B. The New gNB-DUA is supposed to trigger the release the UE-associated signalling connection (not shown).
This clause specifies for F1-C, Xn-C and, in case of EN-DC, for X2-C, how an interface instance is identified in case of network sharing with multiple cell ID broadcast with shared signalling transport.
For UE associated signalling, the interface instance is identified by assigning on F1-C appropriate UE F1AP IDs, on Xn-C appropriate UE XnAP IDs and on X2-C appropriate UE X2AP IDs.
For non-UE associated signalling, the interface instance is identified on F1-C by the assigning an appropriate value to the Transaction ID, on Xn-C and X2-C by including the Interface Instance Indication in the respective message and assigning an appropriate value to it.