Section: Annex I (informative): Indirect Network Sharing of NG-RAN Sharing
Content: This annex clarifies scenarios applicable for Indirect Network Sharing between a Shared NG-RAN and the corresponding participating operator's core network as alternatives for operators who intend to deploy a NG Radio Access Network. Examples of such scenarios include wide-range coverage of rural areas, long-distance road coverage, compatibility with existing networks, service consistency, cooperation with diverse networks, considering different operators' strategies, commercial agreements, and specific rules/legislation in different countries. Two or more operators have deployed or plan to deploy 5G access networks and core networks with MOCN. The challenge for the network operators is the maintenance generated by the interconnection (e.g., number of network interfaces) between the shared RAN and two or more core networks, especially for a large number of shared base stations. For these reasons, it is valuable to introduce a newly supported network sharing scenario as the operators' agreement. In case of Indirect Network Sharing, the communication between the Shared NG-RAN and the Participating Operator’s core network happens via a number of inter-operator interfaces that are independent of the actual number of base stations at the Hosting NG-RAN Operator. There is an agreement between all the operators to work together and build a shared network together cover the entire country, utilizing the different operator’s allocated spectrum appropriately in different parts of the coverage area (for example, Low Traffic Areas and High Traffic Areas). Multiple operators share one NG-RAN, but their 5GCs are independent. UEs access their subscribed PLMN services and/or subscribed services, including Hosted Services, provided by their participating operators respectively, when entering the Shared NG-RAN. The following figures illustrate the example in which Indirect Network Sharing is realized via routing through the Hosting Operator’s core network. - The Hosting NG-RAN Operator 1, as illustrated below, can share its NG-RAN with the participating operators with or without direct connections between the shared access and the core networks of the participating operators. - The Participating NG-RAN Operators 2 and 3, using shared NG-RAN resources provided by the Hosting NG-RAN Operator, e.g., within a specific 5G frequency band or within a specific area, when the Shared NG-RAN does not have direct connections between the shared access and the core networks of the Participating NG-RAN Operators 2 and 3. - The Participating NG-RAN Operator 4, using shared NG-RAN resources provided by the Hosting NG-RAN Operator, with direct connections between the shared NG-RAN and the core networks of the participating operator, is in a MOCN arrangement. Figure I-1: Different options both direct and indirect connections between the Shared NG-RAN and the core networks of the participating operators. Figure I-2: Indirect Network Sharing scenario involving core network of Hosting NG-RAN Operator between the Shared NG-RAN and the core networks of the participating operators. The network sharing partners can set a specific sharing allocation model for the network sharing method they are using. The collection of charging information associated with the sharing method that the UE accesses with can be possible. It is also necessary to understand the charging information between the networks of both parties, e.g., the number of the users, and how long users using a certain shared network method will take. This information is also needed when users use the participating operator's hosted services they have subscribed to and their flexible charging via Shared NG-RAN.