Annex E NG-RAN Architecture for Radio Access Network Sharing with multiple cell ID broadcast

Each NG-RAN node serving a cell identified by a Cell Identity associated with either a subset of PLMNs, or a subset of SNPNs, or a subset of PNI-NPNs is connected to another NG-RAN node via a single Xn-C interface instance.

Each Xn-C interface instance is setup and removed individually.

Xn-C interface instances terminating at NG-RAN nodes which share the same physical radio resources may share the same signalling transport resources. If this option is applied:

• Non-UE associated signalling is associated to an Xn-C interface instance by including an Interface Instance Indication in the XnAP message;
• Node related, non-UE associated Xn-C interface signalling may provide information destined for multiple logical nodes in a single XnAP procedure instance once the Xn-C interface instance is setup;

NOTE 1: If the Interface Instance Indication corresponds to more than one interface instance, the respective XnAP message carries information destined for multiple logical nodes.

• A UE associated signalling connection is associated to an Xn-C interface instance by allocating values for the corresponding NG-RAN node UE XnAP IDs so that they can be mapped to that Xn-C interface instance.

NOTE 2: One possible implementation is to partition the value ranges of the NG-RAN node UE XnAP IDs and associate each value range with an Xn-C interface instance.