 MOCN approach, but it is relatively less flexible, potentially reducing the level of differentiation among the participating operators. 3GPP Rel-15 supports MOCN network sharing architecture, in which only the RAN is shared in the 5G system. However, RAN and AMF support for operators that use more than one PLMN ID is required [3]. 110 Chapter 1 Operator A Operator B Operator A Operator B core network core network core network core network Shared network S1 (eNB-MME) or N2/N3 (gNB-AMF) S1 (eNB-MME) or N2/N3 (gNB-AMF) eNB/gNB eNB/gNB eNB/gNB eNB/gNB eNB/gNB eNB/gNB eNB/gNB eNB/gNB Shared radio Shared radio access network access network Multioperator core network (MOCN) RAN sharing Gateway core network (GWCN) RAN sharing Figure 1.50 3GPP-defined network sharing architecture options [34]. In each case, the network broadcasts system information and supports signaling exchanges that allow the UE to distinguish between up to six different sharing network operators, to obtain service or to perform handover, with no consideration of the underlying network sharing arrangement. As network sharing becomes a central feature of mobile network oper- ation, there is a need to address a wide variety of technical, commercial, and regulatory requirements. Among other things, there is an interest in pooling spectrum, sharing resources asymmetrically and dynamically based on financial considerations and load, and the ability for participating operators to manage and control the use of resources indepen- dently. If a shared NG-RAN is configured to indicate the available core network operators to the UEs for selection, each cell in the shared RAN would then include the PLMNs related to the available core network operators in the shared network in the broadcast sys- tem information. The broadcast system information provides a set of PLMN IDs and option- ally one or more additional set of parameters per PLMN such as cell-ID, tracking areas (TAs), etc. All UEs compliant with the 5G system attempting to connect to NG-RAN must support rece