Managing interaction with home PLMN by a hosting operator in a telecommunication network

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The present invention discloses a method performed by an access and mobility management function (AMF) entity of a second public land mobile network (PLMN) of a hosting operator, the method comprising: receiving, from a user equipment (UE), a message for a registration request associated with a first PLMN of a participating operator selected by the UE; transmitting, to a unified data management (UDM) entity, a request message for a registration procedure, wherein the request message includes a PLMN identifier (ID) of the first PLMN selected by the UE; and receiving, from the UDM entity, subscription data for the UE determined based on the PLMN ID of the first PLMN

Description

MANAGING INTERACTION WITH HOME PLMN BY A HOSTING OPERATOR IN A TELECOMMUNICATION NETWORKThe present invention relates to the field of wireless communication networks. More particularly, the invention relates to a method and system for managing interactions with a Home Public Land Mobile Network (HPLMN) by a hosting operator within a telecommunication network.5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.The principal object of the invention herein is to provide managing interaction with HPLMN by a hosting operator in a telecommunication network.Another object of the invention herein is to provide an AMF indicating participating operator PLMN ID to UDM / AUSF and getting the response based on this information.Yet another object of the invention herein is to provide a new information element (indication) to be added for signaling between the AMF and the UDM / AUSF, i.e., the AMF indication hosting operator PLMN ID, which also indicates to the UDM / AUSF that the UE is registered in the indirect network sharing mode.In an aspect, the objects are achieved by providing a method for managing interaction with an HPLMN in a telecommunication network. The method includes receiving by a first network apparatus a request message from a second network apparatus of the hosting operator. The request message includes a selected PLMN ID of a participating operator in a shared RAN area and a PLMN ID of the hosting operator. Further, the method includes determining by the first network apparatus the subscription data of the UE based on the selected PLMN ID of the participating operator and sending by the first network apparatus the determined subscription data to the second network apparatus of the hosting operator, where the determined subscription data is sent based on the PLMN ID of the participating operator.In another aspect, the objects are achieved by providing a method for managing interaction with an HPLMN in a telecommunication network. The method includes generating by a second network apparatus of a hosting operator a request message. The request message includes a selected PLMN ID of a participating operator in a shared RAN area and a PLMN ID of the hosting operator. Further, the method includes sending by the second network apparatus the request message to a first network apparatus, where the first network apparatus determines the subscription data of the UE based on the selected PLMN ID of the hosting operator and receiving by the second network apparatus the subscription data from the first network apparatus, where the subscription data is received based on the PLMN ID of the hosting operator.In yet another aspect, the objects are achieved by providing a first network apparatus for managing interaction with an HPLMN in a telecommunication network. The first network apparatus includes a processor, a memory including one or more of an AUSF of an HPLMN, PCF of the HPLMN and a UDM of the HPLMN, and an HPLMN interaction controller connected to the processor and the memory. The HPLMN interaction controller receives a request message from a second network apparatus of a hosting operator. The request message includes a selected PLMN ID of a participating operator in a shared RAN area and a PLMN ID of the hosting operator. Further, the HPLMN interaction controller determines the subscription data of the UE based on the selected PLMN ID of the participating operator and sends the determined subscription data to the second network apparatus of the hosting operator, where the determined subscription data is sent based on the PLMN ID of the participating operator.In yet another aspect, the objects are achieved by providing a second network apparatus for managing interaction with an HPLMN in a telecommunication network. The second network apparatus includes a processor, a memory including an AMF, and an HPLMN interaction controller connected to the memory and the processor. The HPLMN interaction controller generates a request message. The request message includes a selected PLMN ID of a participating operator in a shared RAN area and a PLMN ID of the hosting operator. Further, the HPLMN interaction controller sends the request message to a first network apparatus, where the first network apparatus determines the subscription data of the UE based on the selected PLMN ID of the hosting operator and receives the subscription data from the first network apparatus, where the subscription data is received based on the PLMN ID of the hosting operator.These and other aspects of the embodiments will be better understood with the following description and accompanying drawings. The descriptions, while indicating preferred embodiments and specific details, are for illustration and not limitation. Many changes and modifications can be made within the scope of the embodiments, which include all such modifications.The present disclosure provides a method and system for effectively managing interactions with a Home Public Land Mobile Network (HPLMN) by a hosting operator in a telecommunication network.Furthermore, the present disclosure provides a mechanism for an Access and Mobility Management Function (AMF) to indicate a participating operator's Public Land Mobile Network (PLMN) ID to a Unified Data Management (UDM) / Authentication Server Function (AUSF), thereby allowing the UDM / AUSF to return a response with subscription data that is accurately determined based on the User Equipment's (UE's) selected service network.Furthermore, the present disclosure provides a new information element by which the AMF indicates the hosting operator's PLMN ID, which enables the UDM / AUSF to explicitly identify that the UE is registered in an indirect network sharing mode and to apply appropriate policies with full contextual awareness.The invention is illustrated in the accompanying drawings where like reference letters indicate corresponding parts. The embodiments will be better understood from the following description with reference to the drawings.FIG. 1 illustrates an indirect network sharing scenario in which multiple participating operators' CNs connect to the hosting operator's CN to share NR according to prior art.FIG. 2 is a table depicting the UE Subscription data types keys according to prior art.FIG. 3a is a sequence diagram that illustrates an example scenario where the AMF of the HPLMN contacts the UDM in several steps during the Registration procedure for context retrieval according to prior art.FIG. 3b is a sequence diagram that illustrates an example scenario where the AMF of the HPLMN contacts the UDM in several steps during the Registration procedure for context retrieval according to prior art.FIG. 4 is a block diagram that illustrates the hardware components associated with the first network apparatus according to the embodiments as disclosed herein.FIG. 5 is a block diagram that illustrates the hardware components associated with the second network apparatus according to the embodiments as disclosed herein.FIG. 6 is a flow diagram that illustrates a proposed method for managing interaction with an HPLMN in a telecommunication network by the first network apparatus according to the embodiments as disclosed herein.FIG. 7 is a flow diagram that illustrates a proposed method for managing interaction with an HPLMN in a telecommunication network by the second network apparatus according to the embodiments as disclosed herein.FIG. 8 is a sequence diagram that illustrates an example scenario where interactions with an HPLMN are enabled by a hosting operator for indirect network sharing in wireless communication networks according to embodiments as disclosed herein.FIGS. 9 and 10 are sequence diagrams that illustrate the scenarios of the UE being barred due to the deletion of its CAG information according to the prior art.FIG. 11 is a sequence diagram that illustrates the scenario of the UE having the CAG information list associated with the Participating Operator (PLMN) being registered with the UE through the Hosting Operator (HO) according to the embodiments as disclosed herein.FIG. 12 is a sequence diagram that illustrates the scenario of the UE storing or updating the CAG information list of the participating operator according to the embodiments as disclosed herein.The embodiments and their features are detailed with reference to the non-limiting examples shown in the drawings and described below. Well-known components and techniques are omitted to avoid unnecessary detail. The described embodiments are not mutually exclusive and can be combined to form new embodiments. The term "or" is used in a non-exclusive sense unless stated otherwise. The examples provided are for illustrative purposes to aid understanding and should not be seen as limiting the scope of the embodiments.As is existing in the field, embodiments can be described and illustrated in terms of blocks which carry out a described function or functions.　These blocks, which can be referred to herein as managers, units, modules, hardware components or the like, are physically implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and can optionally be driven by firmware and software. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like.　The circuits constituting a block can be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block.　Each block of the embodiments can be physically separated into two or more interacting and discrete blocks without departing from the scope of the disclosure.　Likewise, the blocks of the embodiments can be physically combined into more complex blocks without departing from the scope of the disclosure.In modern telecommunications, network sharing architectures have emerged as a pivotal solution to optimize resource utilization and enhance service delivery. These architectures enable multiple participating operators to share the resources of a single shared network based on agreed allocation methods. The shared network often includes a Radio Access Network (RAN), which is integral to providing seamless connectivity to User Equipment (UE). The shared resources encompass radio frequencies and other essential network components. The allocation of these shared resources is managed by the shared network operator, who distributes them to participating operators based on their planned and current needs, as well as service level agreements.However, several challenges arise from the existing network sharing mechanisms, particularly in scenarios involving indirect network sharing. In such setups, the shared RAN broadcasts multiple Public Land Mobile Network (PLMN) IDs, including those representing both the hosting operator and the participating operators. A UE from a participating operator selects the PLMN ID corresponding to its home network based on established procedures. The serving Access and Mobility Management Function (AMF) then selects core network functions in the PLMN of the participating operator for the UE, adhering to the home-routed roaming architecture principle.One significant issue pertains to the management of subscription data by the Unified Data Management (UDM) system. The UDM provides subscription data that is crucial for maintaining the overall status of the UE, which is contingent upon the PLMN to which the UE is registered. When a UE attempts to register on a PLMN-1 (Participating Operator) via a PLMN-2 (Hosting Operator), the hosting operator's Network Function (NF) communicates with the Home PLMN (HPLMN) operator to facilitate registration based on the subscription data provided by the UDM. The subscription data fetching process heavily relies on the Serving PLMN ID provided by the AMF to the UDM / Authentication Server Function (AUSF).Another critical challenge arises from the handling of Closed Access Group (CAG) information. The CAG information includes at least one PLMN ID and an allowed CAG list, which specifies the CAG cells the UE is permitted to access in the respective PLMN ID. The UE's capability to access 5G networks via CAG cells can be pre-configured or reconfigured based on the subscription data, which includes mobility restrictions and time validity information. Existing mechanisms dictate that the UE deletes the CAG information of the previous PLMN when it receives a new CAG Info list from the currently registering / registered PLMN. This leads to the UE being barred from accessing the PLMN whose CAG information has been deleted.Consider a scenario where the UE is registered to a Participating Operator (PLMN-1) via a Hosting Operator (PLMN-2), and both operators support CAG. The Hosting Operator's NF updates the UE with the CAG Info associated with it (PLMN-2 / CAG-3, CAG-4). Consequently, the UE deletes the previously stored CAG Info of PLMN-1 / CAG-1, CAG-2, and stores the newly received CAG Info. This results in the UE being barred from accessing the CAG cells of the Participating Operator, as the updated CAG information list does not contain entries for the registered PLMN (PLMN-1).Thus, it is desired to address the above-mentioned disadvantages or other shortcomings or at least provide a useful alternative.The drawings help illustrate the technical features but do not limit the embodiments. The disclosure includes any modifications, equivalents, and substitutes beyond those shown. Terms like first, second, etc., are used for distinction and do not limit the elements.Throughout the specification, the definitions of the various terms used in the embodiments are as follows:RAT: Radio access technology defined in 3GPP TS 36.304 and 3GPP TS 38.304, respectively.Indirect Network Sharing: A type of Next Generation Radio Access Network (NG-RAN) sharing in which the communication between the Shared NG-RAN and the Participating Operator's core network is routed through the Hosting NG-RAN Operator's core network.Hosting RAN Operator: The operator that has operational control of a Shared NG RAN, Shared UTRAN.Hosting RAN: The Shared RAN that is owned or controlled by the Hosting RAN Operator.Participating Operator: Authorized operator that is using Shared NG-RAN, Shared E-UTRAN, Shared GERAN or UTRAN resources provided by a Hosting RAN Operator.Shared RAN: GERAN, UTRAN, E-UTRAN or NG-RAN that is shared among a number of operators.CAG cell: A cell in which only members of the CAG can get normal service. Depending on local regulation, the CAG cell can provide emergency services and emergency services fallback also to subscribers who are not members of the CAG.CAG-ID: A CAG-ID is a unique identifier within the scope of one PLMN defined in 3GPP TS 23.003 which identifies a Closed Access Group (CAG) in the PLMN associated with a cell or group of cells to which access is restricted to members of the CAG.The subscription data in this embodiment is any parameters saved at the UDM as subscription information for e.g. consider this below and not limited to as subscription data:Access and Mobility Subscription dataSMF Selection Subscription dataUE context in SMF dataSMS Management Subscription dataSMS Subscription dataUE Context in SMSF dataSession Management Subscription dataIdentifier translationSlice Selection Subscription dataIntersystem continuity ContextLCS privacyLCS mobile originationUser consentUE reachabilityV2X Subscription dataProSe Subscription dataMBS Subscription dataA2X Subscription dataRanging / Sidelink Positioning Subscription dataFIG. 1 illustrates an indirect network sharing scenario in which multiple participating operators' CNs connect to the hosting operator's CN to share NR according to prior art. The hosting RAN operator is an operator that has operational control of a Shared NG RAN, Shared E-UTRAN, Shared GERAN, or UTRAN. The participating operator is an authorized operator that uses Shared NG-RAN, Shared E-UTRAN, Shared GERAN, or UTRAN resources provided by a Hosting RAN Operator. In the case of Indirect Network Sharing, the PLMN ID representing the participating operator, which is broadcasted in the system information, can be a PLMN ID different from the HPLMN ID of the participating operator.Consider that PLMN-1 is the participating operator, PLMN-2 is the Hosting operator, H is the HPLMN operator, and the UE attempts registration on the PLMN-1 via the PLMN-2. When the hosting operator NF communicates with the HPLMN for Registration, it is unclear whether the Hosting PLMN ID or the Participating operator PLMN ID should be used with the UDM. As depicted in FIG. 2, most of the subscription data fetching depends on the provided Serving PLMN ID.The Nudm_UECM_Registration requires the NF to provide a Serving PLMN ID. The Nudm_UECM_Registration service operation name is Nudm_UECM_Registration. The description of the same is as follows: Register UE's serving NF (if NF Type is AMF, SMSF, or NWDAF) or Session's serving NF (if NF Type is SMF) on the UDM.The following inputs are required: NF ID, SUPI, NF Type, Access Type (if NF Type is AMF, SMSF), RAT Type, and GUAMI (if NF Type is AMF), PDU Session ID (if NF Type is SMF), Analytics ID(s) (if NF Type is NWDAF). If NF Type is SMF, DNN or Indication of Emergency Services, S-NSSAI, SMF+PGW-C FQDN for S5 / S8 if the PDU Session supports EPS interworking, Serving Node PLMN ID. If NF type is AMF and Access Type is 3GPP access, Registration type. If NF type is SMSF, SMSF MAP address and / or Diameter address, Serving PLMN ID.FIG. 2 is a table depicting the UE Subscription data types keys as specified in 3GPP TS 23502. At least a mandatory key is required for each Subscription Data Type to identify the corresponding data. Depending on the use case, for some Subscription Data Types, it is possible to use one or multiple sub-keys to further identify the corresponding data. It is important that the HPLMN knows both the PLMN ID of the Hosting operator and that of the Participating operator while fetching context.FIGs. 3a and 3b are a sequence diagram that illustrates an example scenario where the AMF of the HPLMN contacts the UDM in several steps during the Registration procedure for context retrieval according to prior art. As depicted in FIGs. 3a and 3b, in the case of indirect network sharing where the hosting operator, participating operator, and the HPLMN are three different entities, the hosting operator contacts the UDM in the HPLMN in several steps during the Registration procedure for context retrieval. The hosting operator may contact the UDM by providing its own PLMN ID, whereas the UE has selected the participating operator's PLMN ID (PLMN-1). As depicted in FIGs. 3a and 3b, the AMF contacts the UDM in HPLMN for Authentication (Nausf_UEAuthentication) and subsequent Nudm_UECM* and Nudm_SDM procedures.At step 1, the UE (301) sends a Registration Request to a (R)AN (302). At step 2, the (R)AN (302) performs an AMF selection based on the request. At step 3, the (R)AN (302) forwards the registration request to a new AMF (303), which requests the Namf_Communication_UE_ContextTransfer from an old AMF (304) at step 4. At step 5, the old AMF (304) responds with the Namf_Communication_UEContextTransfer response. At step 6, the new AMF (303) sends an Identity Request message to the UE (301) and receives the identity response at step 7. At step 8, the new AMF (303) selects an AUSF based on the identity response. At step 9, the authentication or security between all the components is handled. At step 10, the new AMF (303) sends a Namf_Communication_RegistrationStatusUpdate to the old AMF (304). At step 11, the Identity Request / Response between the UE (301) and the new AMF (303) is performed. At step 12, the new AMF (303) requests a N5g-eir_EquipmentIdentityCheck_Get from the Equipment Identity Register (EIR) and receives it. At step 13, the new AMF (303) selects a UDM. At step 14a, the new AMF (303) requests and receives a Nudm_UECM_Registration and Nudm_SDM_Get from the UDM (308) at steps 14a and 14b respectively. At step 14c, the new AMF (303) requests a Nudm_SDM_Subscribe from the UDM (306). At step 14d, the UDM (308) sends a Nudm_UECM_DeregistrationNotification to the old AMF (304), and at step 14e, the new AMF (303) responds by sending a Nudm_SDM_Unsubscribe to the UDM (308). At step 15, the new AMF (303) performs a Policy Control Function (PCF) selection. At step 16, an AM Policy Association Establishment / Modification is performed between the new AMF (303) and the PCF (305). At step 17, the new AMF (303) requests a Nsmf_PDUSession_UpdateSMContext or Nsmf_PDUSession_ReleaseSMContext from the PCF (305). At step 18, the new AMF (303) requests a UE_Context Modification Request from a N3IWF / TNGF / W-AGF and is responded by the response at step 19. At step 19a, the new AMF (303) sends a Nudm_UECM_Registration to the UDM (308). Then at step 19b, the UDM (308) sends a Nudm_UECM_DeregistrationNotification to the old AMF (304) and is responded with a Nudm_SDM_Unsubscribe at step 19c. At step 21, the new AMF (303) sends a registration accept message to the UE (301).In the existing mechanisms, the Unified Data Management (UDM) provides subscription data based on which the whole UE status is maintained. It depends on what PLMN the UE is registered to. The UE attempts registration on a PLMN-1 (Participating operator) via a PLMN-2 (Hosting operator). When the hosting operator Network Function (NF) communicates with the HPLMN operator for Registration, it is based on what the subscription data from the UDM should be given. Most of the subscription data fetching depends on the Serving PLMN ID provided by AMF to UDM / AUSF.Embodiments disclosed herein provide a first network apparatus, a second network apparatus, and a method for managing interaction with an HPLMN in a telecommunication network. The solution proposes that the Hosting Operator's AMF shall indicate the selected PLMN ID / serving network name, i.e., of PLMN-1 of the Participating operator, to HPLMN (AUSF / UDM) while using the service of HPLMN, e.g., UDM / AUSF Services, such as in Nudm_UECM_Registration service operation or Nudm_SDM_Get operation, Nausf_UEAuthentication. The UDM will provide subscription data based on the indicated participating operator, i.e., PLMN ID of the participating operator. Further, the solution proposes that the Hosting Operator's AMF shall indicate the Hosting operator PLMN ID, i.e., of PLMN-2, while using the service of HPLMN, e.g., UDM / AUSF Services, such as in Nudm_UECM_Registration service operation or Nudm_SDM_Get operation, Nausf_UEAuthentication. The UDM will provide subscription data to the AMF based on the new information element indicating the hosting operator PLMN ID.Referring now to the drawings, and more particularly to FIGS. 4 through 12 where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.FIG. 4 is a block diagram illustrating the hardware components associated with the first network apparatus (400) according to the embodiments disclosed herein. Examples of the first network apparatus (400) can include, but are not limited to, Base Stations (such as macro cells, small cells, femtocells, picocells) for wireless communication, Antennas and RF Units (e.g., multiple input multiple output (MIMO), beamforming) to enhance signal coverage and data throughput, Core Network Equipment (e.g., MMEs, S-GWs, P-GWs in 4G, AMFs, UPFs in 5G) for data routing, mobility, and session control, Network Function Virtualization (NFV) and Software-Defined Networking (SDN) for dynamic resource allocation and scalability, Edge Computing Nodes (e.g., MEC servers) for low-latency processing, Backhaul and Transport Equipment (e.g., fiber-optic links, microwave relays, Ethernet switches) to connect base stations to the core network, Network Management Systems (NMS) and Operation Support Systems (OSS) for network configuration, fault management, and optimization, Radio Network Controllers (RNCs) in 3G, Distributed Units (DUs) and Centralized Units (CUs) in 5G, Network Slicing Components for virtualized resource allocation, and Security elements (e.g., Firewalls, IDS, AAA Servers) for secure communication.Examples of the User Equipment (UE) can include, but are not limited to, Consumer Electronics (such as Mobile Phones and Smartphones), Tablets, Wearable Devices, Computing Devices (such as Laptops, Notebooks, Desktops, Workstations, etc.), IoT Devices, Automotive Systems (such as connected cars, Autonomous Vehicles, Vehicle-to-Everything (V2X) communication devices, etc.), Enterprise Devices such as robotics, Specialized Equipment (such as Medical Devices, Public Safety Devices, etc.), and Media Devices (such as Gaming Consoles, Streaming Devices, etc.).In an embodiment illustrated in FIG. 4, the first network apparatus (400) includes a processor (401), a memory (402), a communicator (403), and an HPLMN interaction controller (404). The processor (401) manages interaction with an HPLMN in a telecommunication network. Communication between the processor (401), the memory (402), the communicator (403), and the HPLMN interaction controller (404) is facilitated by the processor (401). Instructions stored in the memory (402) are executed by the processor (401), which also manages interaction with the HPLMN in a telecommunication network. The processor (401) may include one or a plurality of processors such as a Central Processing Unit (CPU), an Application Processor (AP), a Graphics Processing Unit (GPU), a Visual Processing Unit (VPU), and / or a Neural Processing Unit (NPU).The memory (402) stores the operating system, application software, and temporary data used by the processor (401). Instructions to be executed by the processor (401) are stored in the memory (402). The memory (402) is not limited to volatile memory and / or non-volatile memory and may include a plurality of computer-readable storage media. Non-volatile storage elements such as magnetic hard disks, optical disks, floppy disks, flash memories, EPROM, or EEPROM memories may be included in the memory (402). In some examples, the memory (402) may be considered a non-transitory storage medium, indicating that it is not embodied in a carrier wave or a propagated signal but not necessarily non-movable. The memory (402) stores one or more of an AUSF of an HPLMN and a UDM of the HPLMN.The communicator (403) facilitates communication between the first network apparatus (400) and the second network apparatus (500), supporting various communication protocols such as Transmission Control Protocol / Internet Protocol (TCP / IP), User Datagram Protocol (UDP), and second-generation Digital Video Broadcasting by Satellite (DVB-S2). Internal communication between hardware components via one or more networks is also facilitated by the communicator (403). An electronic circuit specific to a standard that enables wired or wireless communication is included in the communicator (403). The communicator (403) receives a request message from the second network apparatus (500) of a hosting operator.In an embodiment, the HPLMN interaction controller (404) is a hardware component designed to manage interaction with an HPLMN in a telecommunication network. This hardware implementation ensures efficient and reliable execution of processes integral to managing interaction with the HPLMN in a telecommunication network. The HPLMN interaction controller (404) includes a multi-core architecture tailored to optimize managing interaction with an HPLMN in a telecommunication network. Each core within the architecture is specifically designed to execute distinct functions.In an embodiment, the HPLMN interaction controller (404) receives a request message from a second network apparatus (500) of a hosting operator. The request message includes a selected PLMN ID of a participating operator in a shared RAN area and a PLMN ID of the hosting operator.In an embodiment, the HPLMN interaction controller (404) determines the subscription data of the UE based on the selected PLMN ID of the participating operator and sends the determined subscription data to the second network apparatus (500) of the hosting operator, where the determined subscription data is sent based on the PLMN ID of the participating operator.FIG. 5 is a block diagram illustrating the hardware components associated with the second network apparatus (500) according to the embodiments disclosed herein. Examples of the second network apparatus (500) can include, but are not limited to, Base Stations (such as macro cells, small cells, femtocells, picocells) for wireless communication, Antennas and RF Units (e.g., multiple input multiple output (MIMO), beamforming) to enhance signal coverage and data throughput, Core Network Equipment (e.g., MMEs, S-GWs, P-GWs in 4G, AMFs, UPFs in 5G) for data routing, mobility, and session control, Network function Virtualization (NFV) and Software-Defined Networking (SDN) for dynamic resource allocation and scalability, Edge Computing Nodes (e.g., MEC servers) for low-latency processing, Backhaul and Transport Equipment (e.g., fiber-optic links, microwave relays, Ethernet switches) to connect base stations to the core network, Network Management Systems (NMS) and Operation Support Systems (OSS) for network configuration, fault management, and optimization, Radio Network Controllers (RNCs) in 3G, Distributed Units (DUs) and Centralized Units (CUs) in 5G, Network Slicing Components for virtualized resource allocation, Security elements (e.g., Firewalls, IDS, AAA Servers) for secure communication.In an embodiment illustrated in FIG. 5, the second network apparatus (500) includes a processor (501), a memory (502), a communicator (503), and an HPLMN interaction controller (504). The processor (501) manages interaction with an HPLMN in a telecommunication network. Communication between the processor (501), the memory (502), the communicator (503), and the HPLMN interaction controller (504) is facilitated by the processor (501). Instructions stored in the memory (502) are executed by the processor (501), which also manages interaction with the HPLMN in a telecommunication network. The processor (501) may include one or a plurality of processors such as a Central Processing Unit (CPU), an Application Processor (AP), a Graphics Processing Unit (GPU), a Visual Processing Unit (VPU), and / or a Neural Processing Unit (NPU).The memory (502) stores the operating system, application software, and temporary data used by the processor (501). Instructions to be executed by the processor (501) are stored in the memory (502). The memory (502) is not limited to volatile memory and / or non-volatile memory and may include a plurality of computer-readable storage media. Non-volatile storage elements such as magnetic hard disks, optical disks, floppy disks, flash memories, EPROM, or EEPROM memories may be included in the memory (502). In some examples, the memory (502) may be considered a non-transitory storage medium indicating that it is not embodied in a carrier wave or a propagated signal but not necessarily non-movable. The memory (502) stores an AMF.The communicator (503) facilitates communication between the second network apparatus (500) and the first network apparatus (400), supporting various communication protocols such as Transmission Control Protocol / Internet Protocol (TCP / IP), User Datagram Protocol (UDP), and second-generation Digital Video Broadcasting by Satellite (DVB-S2). Internal communication between hardware components via one or more networks is also facilitated by the communicator (503). An electronic circuit specific to a standard that enables wired or wireless communication is included in the communicator (503). The communicator (503) sends the request message to the first network apparatus (400).In an embodiment, the HPLMN interaction controller (504) is a hardware component designed to manage interaction with an HPLMN in a telecommunication network. This hardware implementation ensures efficient and reliable execution of processes integral to managing interaction with the HPLMN in a telecommunication network. The HPLMN interaction controller (504) includes a multi-core architecture tailored to optimize managing interaction with the HPLMN in a telecommunication network. Each core within the architecture is specifically designed to execute distinct functions.In an embodiment, the HPLMN interaction controller (504) generates a request message including a selected PLMN ID of a participating operator in a shared RAN area and a PLMN ID of the hosting operator.In an embodiment, the HPLMN interaction controller (504) sends the request message to a first network apparatus (400) where the first network apparatus (400) determines the subscription data of the UE based on the selected PLMN ID of the hosting operator and receives the subscription data from the first network apparatus (400) where the subscription data is received based on the PLMN ID of the hosting operator.FIG. 6 is a flow diagram illustrating a proposed method for managing interaction with an HPLMN in a telecommunication network by the first network apparatus (400) according to the embodiments disclosed herein. At step 601, the method includes receiving by a first network apparatus (400) a request message from a second network apparatus (500) of the hosting operator. The request message includes a selected PLMN ID of a participating operator in a shared RAN area and a PLMN ID of the hosting operator. The request message from the second network apparatus (500) of the hosting operator is received during one of a Nudm_UECM_Registration service operation, a Nudm_SDM_Get operation, and a Nausf_UEAuthentication operation. At step 602, the method includes determining by the first network apparatus (400) the subscription data of the UE based on the selected PLMN ID of the participating operator. The subscription data sent to the second network apparatus (500) of the hosting operator includes information elements indicating the selected PLMN ID of the participating operator and the PLMN ID of the hosting operator. At step 603, the method includes sending by the first network apparatus (400) the determined subscription data to the second network apparatus (500) of the hosting operator where the determined subscription data is sent based on the PLMN ID of the participating operator. The PLMN ID of the hosting operator indicates to the first network apparatus (400) that the UE is registered / registering in an indirect network sharing mode.In an embodiment, the first network apparatus (400) includes one or more of an AUSF, H-PCF of the HPLMN, H-SMF of the HPLMN and a UDM of the HPLMN and the second network apparatus (500) includes an AMF, (V-)PCF, (V-)SMF.FIG. 7 is a flow diagram illustrating a proposed method for managing interaction with an HPLMN in a telecommunication network by the second network apparatus (500) according to the embodiments disclosed herein. At step 701, the method includes generating by a second network apparatus (500) of a hosting operator a request message. The request message includes a selected PLMN ID of a participating operator in a shared RAN area and a PLMN ID of the hosting operator. The request message to the second network apparatus (500) of the hosting operator is at least one of a Nudm_UECM_Registration service operation, a Nudm_SDM_Get operation, and a Nausf_UEAuthentication operation. At step 702, the method includes sending by the second network apparatus (500) the request message to a first network apparatus (400) where the first network apparatus (400) determines the subscription data of the UE based on the selected PLMN ID of the hosting operator. The subscription data received from the second network apparatus (500) of the hosting operator includes information elements indicating the selected PLMN ID of the participating operator and the PLMN ID of the hosting operator. At step 703, the method includes receiving by the second network apparatus (500) the subscription data from the first network apparatus (400) where the subscription data is received based on the PLMN ID of the hosting operator. The PLMN ID of the hosting operator indicates to the first network apparatus (400) that the UE is registered in an indirect network sharing mode.In an embodiment, the first network apparatus (400) includes one or more of an AUSF, (H-)PCF, (H-)SMF of an HPLMN and a UDM of the HPLMN and the second network apparatus (500) includes an AMF, (V-)SMF, (V-)PCF.FIG. 8 is a sequence diagram that illustrates an example scenario wherein interactions with an HPLMN are enabled by a hosting operator for indirect network sharing in wireless communication networks according to embodiments as disclosed herein. In the depicted figure, the UE, the RAN, and the AMF belong to the hosting network and the UDM belongs to the HPLMN network whereas the SMF and the DN belong to the participating network. At step 1, the UE (801) sends a registration request to the RAN (802) and at step 2, the RAN (802) performs AMF selection. At step 3, the RAN (802) sends a registration request to the AMF (803), then at step 4, the AMF (803) requests an identity from the UE (801) and is responded at step 5. At step 6, the AMF (803) performs UDM selection and at step 7, the AMF (803) sends a signaling request including Hosting Operator PLMN ID PLMN-2 and Participating Operator PLMN ID PLMN-1 to the UDM (804). At step 8, the UDM (804) sends the signaling response to the AMF (803). At step 9, the AMF (803) sends a registration accept message to the UE (801).The figure depicts an example scenario wherein the Hosting Operator's AMF often communicates with the UDM in HPLMN by means of signaling procedures for fetch / update / subscribe operations. The Hosting Operator's AMF indicates one or more of the selected PLMN ID / serving network name (e.g., PLMN-1 of the Participating operator) and optionally also indicate PLMN-2 of Hosting Operator to HPLMN (AUSF / UDM) while using service of HPLMN example UDM / AUSF Services e.g., in Nudm_UECM_Registration service operation or Nudm_SDM_Get operation, Nausf_UEAuthentication.The UDM then provides subscription information to the AMF based on at least one of the PLMN ID of the participating operator or the PLMN ID of the hosting operator. The Subscription information provided by the UDM to AMF includes at least one of the following parameters and not limited to GPSI List, Internal Group ID-list, Subscribed UE-AMBR, Subscribed UE-Slice-MBR(s), Subscribed S-NSSAIs, Default S-NSSAIs, Slice Usage Policy information, S NSSAIs subject to Network Slice-Specific Authentication and Authorization, Network Slice Simultaneous Registration Group Information, Network Slice validity time information, UE Usage Type, RAT restriction, Forbidden area, Service Area Restriction, Core Network type restriction, CAG information, CAG information Subscription Change Indication, RFSP Index, Subscribed Periodic Registration Timer, Subscribed Active Time, MPS priority, MCX priority, AMF Associated Expected UE Behaviour parameters, Steering of Roaming SoR Update Indicator for Initial Registration, SoR Update Indicator for Emergency Registration, Network Slicing Subscription Change Indicator, Provide the UE with the full set of subscribed S-NSSAIs, Tracing Requirements, Inclusion of NSSAI in RRC Connection Establishment, Allowed Service Gap Time, Subscribed DNN list, LADN Service Area, UDM Update Data, NB-IoT UE priority, Enhanced Coverage Restriction, NB-IoT Enhanced Coverage Restriction, IAB-Operation allowed, MBSR Operation allowed, Charging Characteristics, Extended idle mode DRX cycle length, PCF Selection Assistance info, AerialUESubscriptionInfo, 5G Access Stratum-based Time Synchronization, Service Data Routing Indicator, ODB for Packet services, QMC Configuration information, NCR-Operation allowed.Similarly, the hosting operator's NF may include both (hosting and participating) PLMN IDs or at least one of the PLMN ID of the participating operator or the PLMN ID of the hosting operator for communication with any other NF in the HPLMN.Embodiments disclosed herein provide a method and a system for CAG information sharing between participating & hosting operator core networks. The proposed solution, the hosting Operator's NF (e.g., AMF) updates the UE with CAG Info related to the Participating Operator (i.e., PLMN-1 considering an example PLMN-1 which is a participating operator with CAG-1, CAG-2 associated with it, PLMN-2 Hosting operator with CAG-3, CAG-4 associated with it). HPLMN operator UDM gives all the relevant CAG information list to AMF i.e., for all PLMNs (PLMN-1 / CAG-1, CAG-2, PLMN-2 / CAG-3, CAG-4) involved. UE is registering or registered on PLMN-1 via the PLMN-2 Hosting operator (e.g., AMF of PLMN-2) updates CAG Information (CAG-3, CAG-4) to the UE in one of the NAS Messages (e.g., Registration Accept) as per the current state of the art) by sending a DL NAS Message (e.g., Registration Accept or DL NAS TRANSPORT etc. containing UPU container / UCU Container / SOR Container with CAG information list IE (e.g., PLMN-1 / CAG-1, CAG-2) which results in the UE having the CAG information associated with the participating operator that avoids the UE being barred to access PLMN-1 cells.In an embodiment, the Hosting Operator's NF (e.g., AMF) shall indicate the selected PLMN ID / serving network name (e.g., PLMN-2 as the Hosting Operator) and optionally also indicate PLMN-1 as Participating Operator to HPLMN (AUSF / UDM) using UDM Service. , In another embodiment, the serving PLMN ID / selected PLMN ID as participating operator(PO) PLMN ID and Optionally includes Hosting operator (HO)'s PLMNCAG information consists of one or more of the following:A) PLMN ID and the allowed CAG list (i.e. for e.g. CAG-1, CAG-2)B) Indication that the UE is only allowed to access 5GS via CAG cells (CAGonly)- "Indication that the UE is only allowed to access 5GS via CAG cells" is not set (i.e., the UE is allowed to access 5GS via non-CAG cells).- "Indication that the UE is only allowed to access 5GS via CAG cells" is set (i.e., the UE is not allowed to access 5GS via non-CAG cells.To use CAG, the UE that supports CAG as indicated as part of the UE 5GMM Core Network Capability, may be pre-configured or (re)configured with the following CAG information, included in the subscription as part of the Mobility Restrictions:- an Allowed CAG list i.e. a list of CAG Identifiers the UE is allowed to access; and- each entry of the Allowed CAG list may be associated with time validity information containing one or more time periods; and- optionally, a CAG-only indication whether the UE is only allowed to access 5GS via CAG cells (see TS 38.304

[0050] for how the UE identifies whether a cell is a CAG cell);The UE selects / reselect a cell based on CAG information as described in TS 23.122.UE configuration, subscription aspects and storage: To use CAG, the UE, that supports CAG as indicated as part of the UE 5GMM Core Network Capability, may be pre-configured or (re)configured with the following CAG information, included in the subscription as part of the Mobility Restrictions:- an Allowed CAG list i.e. a list of CAG Identifiers the UE is allowed to access; and- each entry of the Allowed CAG list may be associated with time validity information containing one or more time periods; and- optionally, a CAG-only indication whether the UE is only allowed to access 5GS via CAG cells (see TS 38.304

[0050] for how the UE identifies whether a cell is a CAG cell);The HPLMN may configure or re-configure a UE with the above CAG information using the UE Configuration Update procedure for access and mobility management related parameters described in clause 4.2.4.2 of TS 23.502 [3].The above CAG information is provided by the HPLMN on a per PLMN basis. In a PLMN the UE shall only consider the CAG information provided for this PLMN. The entries of the Allowed CAG list with time validity information are provided to the UE only if the UE indicates support of CAG with validity information.When the UE is roaming and the Serving PLMN provides CAG information, the UE shall update only the CAG information provided for the Serving PLMN while the stored CAG information for other PLMNs is not updated. When the UE is not roaming and the HPLMN provides CAG information, the UE shall update the CAG information stored in the UE with the received CAG information for all the PLMNs.If the UE is "CAG supported" and the AMF needs to update the CAG information of the UE, the AMF may include the CAG information as part of the Mobility Restrictions in the Registration Accept message.For example, if PLMN 1 is participating operator with CAG 1, CAG-2 associated with it and if PLMN-2 is hosting operator with CAG 3, CAG-4 associated with it. Further considering the UDM gives all the relevant CAG information list to AMF i.e. for all PLMNs (PLMN-1 / CAG 1, CAG-2, PLMN-2 / CAG-3, CAG-4) involved and the UE is registering or registered on PLMN-1 via the PLMN-2. Further hosting operator (e.g., AMF of PLMN-2) updates CAG Information (CAG-3, CAG-4) to the UE in one of the NAS Messages (e.g., Registration Accept / DL NAS TRANSPORT / UE CONFIGURATION COMMAND) as per the current state of the art. In such cases the UE deletes the CAG information stored (if any) for PLMN-1 (i.e., CAG-1 & CAG-2). This results in UE being barred to access PLMN-1 cells (as the newly updated "CAG information list" does not contain an entry for the registered PLMN i.e., PLMN-1).In contrast to the existing mechanisms, in the proposed solution, the Hosting Operator's AMF updates the UE with CAG Info related to the Participating operator by sending a DL NAS Message (for e.g., Registration Accept or DL NAS TRANSPORT etc. containing UPU container / UCU Container / SOR Container with CAG information list IE.FIGS. 9-10 are sequence diagrams that illustrate the scenario of the UE being barred due to the deletion of its CAG information, according to the prior art.Referring to the FIG. 9, considering the preconditions to be:(a) PLMN-1: Participating operator with CAG-1, CAG-2 associated with it. (b) PLMN-2: Hosting operator with CAG-3, CAG-4 associated with it.(c) H: HPLMN operator.(d) Participating Operator NF (e.g., UDM / AUSF) gives all the relevant CAG information list to Hosting Operator NF (e.g., AMF) i.e. for all PLMNs (PLMN-1 / CAG-1, CAG-2, PLMN-2 / CAG-3, CAG-4) involved.(e) UE is registering or registered on PLMN-1 via the PLMN-2. Hosting operator (e.g., AMF of PLMN-2) updates CAG Information (CAG 3, CAG-4) to the UE in one of the NAS Messages (e.g., Registration Accept) as per the current state of the art.In the above mentioned scenario, the UE will delete the CAG information stored (if any) for PLMN-1 (i.e., CAG-1 & CAG-2).

[0041] This results in UE being barred to access PLMN-1 cells (as the newly updated "CAG information list" does not contain an entry for the registered PLMN i.e., PLMN-1).At step 1 of the FIG. 9, the UE is registering / registered on PO via HO. Further the UDM sends configured / updated CAG Information of all the involved PLMNs (both HO & PO) as depicted in step 2. Further the Configured / Updated CAG information is received by Hosting Operator's AMF via Nudm_SubscriberDataManagement Service with Access and Mobility Subscription data set to CAG information (e.g., AMF-2 / PLMN2) from UDM or PCF or any other core network entity (e.g., Nudm_SDM_Notification (CAG information list: CAG-1, CAG-2 for PLMN1, CAG-3, CAG-4 for PLMN2)) as depicted at step 3. At step 4, the hosting operator's AMF updates the UE with CAG Info related to itself i.e., PLMN-2 by sending a DL NAS Message (for e.g., Registration Accept or DL NAS TRANSPORT etc. containing UPU container / UCU Container / SOR Container with CAG information list IE (e.g., PLMN-2:CAG-3, CAG-4)). Step 5 depicts the UE that acknowledges the CAG Info received by sending a NAS Message (UL NAS TRANSPORT containing UPU Ack / UCU Ack / SOR Ack). Further AMF informs the UDM that the UE received the CAG information using the Nudm_SDM_Info service operation at step 6. Step 7 depicts the UE that deletes the CAG Info associated with PLMN-1 if any (e.g., CAG-1, CAG-2) and stores the new CAG Info (e.g., CAG-3, CAG-4) received from / via PLMN-2.Referring to the FIG. 10, considering the following pre-conditions:(a) PLMN-1: Participating operator with CAG-1, CAG-2 associated with it. (b) PLMN-2: Hosting operator with CAG-3, CAG-4 associated with it.(c) H: HPLMN operator.(d) UDM gives CAG information list of only the serving PLMN (i.e., Hosting Operator PLMN-2 / CAG-3, CAG-4) to AMF.(e) UE is registering or registered on PLMN-1 via the PLMN-2.Hosting operator (e.g., AMF of PLMN-2) updates CAG Information (CAG 3, CAG-4) to the UE in one of the NAS Messages (e.g., Registration Accept) as per the current state of the art.In the above scenario, the UE deletes the CAG information stored (if any) for PLMN-1 (i.e., CAG-1 & CAG-2). This results in UE being barred to access PLMN-1 cells (as the newly updated "CAG information list" does not contain an entry for the registered PLMN i.e., PLMN-1).Step 1 of the FIG. 10 illustrates the UE is registering / registered on PO via HO. The UE selects PLMN-1. At step 2, the UDM sends configured / updated CAG Information of only the serving PLMN (i.e., the CAG Info associated with the Hosting Operator's PLMN, e.g., PLMN-2 / CAG-3, CAG-4). At step 3, the Configured / Updated CAG information is received by Hosting Operator's AMF via Nudm_SubscriberDataManagement Service with Access and Mobility Subscription data set to CAG information (e.g., AMF-2 / PLMN2) from UDM or PCF or any other core network entity (e.g., Nudm_SDM_Notification (CAG information list: CAG-3, CAG-4 for PLMN2)). At step 4, the Hosting Operator's AMF updates the UE with CAG Info related to itself i.e., PLMN-2 by sending a DL NAS Message (for e.g., Registration Accept or DL NAS TRANSPORT etc. containing UPU container / UCU Container / SOR Container with CAG information list IE (e.g., PLMN-2 / CAG-3, CAG-4)). At step 5, the UE acknowledges the CAG Info received by sending a NAS Message (UL NAS TRANSPORT containing UPU Ack / UCU Ack / SOR Ack). At step 6, the AMF informs the UDM that the UE received the CAG information using the Nudm_SDM_Info service operation. At step 7, the UE deletes the CAG Info associated with PLMN-1 if any (e.g., CAG-1, CAG-2) and stores the new CAG Info (e.g., CAG-3, CAG-4) of PLMN-2.FIG. 11 is a sequence diagram that illustrates the scenario of the UE having the CAG information list associated with PO (PLMN-1 / CAG-1, CAG-2) being registered with the UE through the HO, according to the embodiments as disclosed herein. The figure illustrates the proposed solution where the Hosting Operator's AMF updates the UE with CAG Info related to the Participating Operator i.e., PLMN-1 by sending a DL NAS Message (for e.g., Registration Accept or DL NAS TRANSPORT etc. containing UPU container / UCU Container / SOR Container with CAG information list IE (e.g., PLMN-1 / CAG-1, CAG-2)).In an embodiment, at step 1, the UE is registering / registered on PO via HO i.e. UE has selected the participating operator e.g. PLMN-1. At step 2, the UDM sends configured / updated CAG Information of all the involved PLMNs (both HO & PO). Step 3 depicts Configured / Updated CAG information is received by Hosting Operator's AMF, for e.g., via Nudm_SubscriberDataManagement Service with Access and Mobility Subscription data set to CAG information (e.g., AMF-2 / PLMN2) from UDM or PCF or any other core network entity (e.g., Nudm_SDM_Notification (CAG information list: CAG-1, CAG-2 for PLMN1, CAG-3, CAG-4 for PLMN2)). At Step 4, the Hosting Operator's AMF updates the UE with CAG Info related to the Participating Operator / selected PLMN ID i.e., PLMN-1 by sending a DL NAS Message (for e.g., Registration Accept or DL NAS TRANSPORT etc. containing UPU container / UCU Container / SOR Container with CAG information list IE (e.g., PLMN-1:CAG-1, CAG 2)). At step 5, the UE acknowledges the CAG Info received by sending a NAS Message (UL NAS TRANSPORT containing UPU Ack / UCU Ack / SOR Ack). At step 6, AMF informs the UDM that the UE received the CAG information using the Nudm_SDM_Info service operation. At step 7, the UE updates / stores the newly received CAG Info e.g., PLMN-1: CAG-1, CAG-2. UE has the CAG Info list associated with the PO itself.The participation operator PLMN ID in this embodiment, is also called as the selected PLMN ID or the serving PLMN ID.FIG. 12 is a sequence diagram that illustrates the scenario of the UE storing / updating the CAG information list of the participating operator according to the embodiments as disclosed herein. In an embodiment, the Hosting Operator's NF (e.g., AMF) shall indicate the selected PLMN ID / serving network name (e.g., PLMN-2 as the Hosting Operator) and optionally also indicate PLMN-1 as Participating Operator to HPLMN NF (AUSF / UDM) , in another embodiment the serving PLMN ID as participating operator(PO) PLMN ID and Optionally includes Hosting operator (HO)'s PLMN using any of the signals between the NFs, for example, UDM Service, e.g., in Nudm_UECM_Registration service operation. In an embodiment, Configured / Updated CAG information is received by Hosting Operator's AMF (e.g., AMF-2 / PLMN2), for example, via Nudm_SubscriberDataManagement Service with Access and Mobility Subscription data set to CAG information associated with Participating Operator (e.g., AMF-1 / PLMN1) from UDM or PCF or any other core network entity (e.g., Nudm_SDM_Notification (CAG information list CAG-1 CAG-2 for PLMN1)). UDM can optionally send the CAG Information for Hosting Operator as well (e.g., PLMN-2 / CAG-3 CAG-4). In an embodiment, the Hosting Operator's AMF updates the UE with CAG Info related to the Participating Operator, i.e., PLMN-1, by sending a DL NAS Message (for example, Registration Accept or DL NAS TRANSPORT, etc., containing UPU container / UCU Container / SOR Container with CAG information list IE (e.g., PLMN-1 / CAG-1 CAG-2)).In an embodiment, at step 1, the UE is registering / registered on PO via HO. At step 2, the hosting operator NF, e.g., AMF, sends a signal to HPLMN NF, e.g., UDM, and includes the Serving PLMN ID as Hosting operator (HO) PLMN ID and optionally also includes Participating operator (PO)'s PLMN, in another embodiment the serving PLMN ID as participating operator(PO) PLMN ID and Optionally includes Hosting operator (HO)'s PLMN Nudm_UECM_Registration ID in UDM Service, e.g., in service / NAusf_UEAuth_req / NUDM_SDM_GET operation, etc., i.e., in at least one of the signal messages from the NF of hosting operator to the NF of the HPLMN. The inputs required include Serving PLMN ID = PLMN-2, Serving PLMN Name = Hosting Operator, PLMN ID = PLMN-1, PLMN Name = Participating Operator. The signal will additionally identify the sent PLMN ID is at least one of the Hosting operator or the Participating operator, for example, with the explicit flag. At step 3, the HPLMN NF, e.g., UDM / AUSF, based on the inputs received from the hosting operator, e.g., AMF, sends configured / updated CAG Information associated with Participating Operator and / or optionally CAG Info of HO can also be included. At step 4, Configured / Updated CAG information is received by Hosting Operator's NF, e.g., AMF, via Nudm_SubscriberDataManagement Service with Access and Mobility Subscription data set to CAG information (e.g., AMF-2 / PLMN2) from UDM or PCF or any other core network entity (e.g., Nudm_SDM_Notification (CAG information list CAG-1 CAG-2 for PLMN1 and / or CAG-3 CAG-4 for PLMN-2)). At step 5, the Hosting Operator's NF (e.g., AMF) updates the UE with CAG Info related to the Participating Operator, i.e., PLMN-1, by sending a DL NAS Message (for example, Registration Accept or DL NAS TRANSPORT or UE configuration update, etc., containing UPU container / UCU Container / SOR Container with CAG information list IE (e.g., PLMN-1 / CAG-1 CAG-2 PLMN-2 / CAG-3 CAG-4)). At step 6, the UE updates / stores the newly received CAG Information list of PLMN-1 (e.g., PLMN-1 / CAG-1 CAG-2) that is of the participating operator and optionally also the values received for hosting operator, e.g., PLMN-2 / CAG-3 CAG-4.In an embodiment, after receiving CAG information from HPLMN, e.g., UDM, or based on the determination of the NF at HO, e.g., AMF, the HO will provide CAG information related to HO as CAG information of Participating operator, i.e., CAG-3 CAG-4 as CAG information of PLMN-1 (PLMN-1CAG-3 CAG-4) to the UE. The NG RAN shall broadcast PLMN-1 CAG-3 CAG-4 as the allowed CAG list in a given cell. The UE assumes that PLMN-1 CAG-3 CAG-4 is the allowed CAG list for PLMN-1 and the UE selects the allowable cell accordingly.In an embodiment, CAG Info List is being extensively used. However, in yet another embodiment, solutions talked about herein are applicable to Extended CAG Info List as well. In an embodiment, CAG information Subscription Change Indication shall also trigger the HO's NF (e.g., AMF) to update the UE with the relevant CAG Info List. In an embodiment, currently UDM / AUSF of HPLMN are not aware if UE is registered in the indirect network sharing mode and which are the Participating operator PLMN ID and Hosting operator PLMN ID. Thus, UDM cannot influence what UE services should be allowed and what UE should not access, i.e., there is no HPLMN control over its own UE, which is not desirable. For Indirect network sharing concept, the proposed solution is mandatory.The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. While the preferred embodiments have been described, those skilled in the art will recognize that modifications can be made within the scope of the described embodiments.

Claims

1.A method performed by an access and mobility management function (AMF) entity of a second public land mobile network (PLMN) of a hosting operator, the method comprising:receiving, from a user equipment (UE), a message for a registration request associated with a first PLMN of a participating operator;transmitting, to a unified data management (UDM) entity, a request message for a registration procedure, wherein the request message includes a PLMN identifier (ID) of the first PLMN; andreceiving, from the UDM entity, subscription data for the UE based on the PLMN ID of the first PLMN.2.The method of claim 1,wherein the request message further includes a PLMN ID of the second PLMN of the hosting operator.3.The method of claim 1, further comprising:transmitting, to the UE, a registration accept message.4.The method of claim 1,wherein the first PLMN of the participating operator is selected by the UE.5.A method performed by a unified data management (UDM) entity, the method comprising:receiving, from an access and mobility management function (AMF) entity of a second public land mobile network (PLMN) of a hosting operator, a request message for a registration procedure, wherein the request message includes a PLMN identifier (ID) of a first PLMN of a participating operator; andtransmitting, to the AMF entity, subscription data for a user equipment (UE) based on the PLMN ID of the first PLMN.6.The method of claim 5,wherein the request message further includes a PLMN ID of the second PLMN of the hosting operator.7.The method of claim 6, further comprising:identifying, based on the PLMN ID of the second PLMN, that the UE is registered in indirect network sharing.8.An access and mobility management function (AMF) entity of a second public land mobile network (PLMN) of a hosting operator, the AMF entity comprising:at least one transceiver;at least one processor communicatively coupled to the at least one transceiver; andmemory, communicatively coupled to the at least one processor, storing instructions executable by the at least one processor individually or in any combination to cause the AMF entity to:receive, from a user equipment (UE) via the at least one transceiver, a message for a registration request associated with a first PLMN of a participating operator;transmit, to a unified data management (UDM) entity via the at least one transceiver, a request message for a registration procedure, wherein the request message includes a PLMN identifier (ID) of the first PLMN; andreceive, from the UDM entity via the at least one transceiver, subscription data for the UE based on the PLMN ID of the first PLMN.9.The AMF entity of claim 8,wherein the request message further includes a PLMN ID of the second PLMN of the hosting operator.10.The AMF entity of claim 8, wherein the instructions further cause the AMF entity to:transmit, to the UE via the at least one transceiver, a registration accept message.11.The AMF entity of claim 8,wherein the first PLMN of the participating operator is selected by the UE.12.A unified data management (UDM) entity comprising:at least one transceiver;at least one processor communicatively coupled to the at least one transceiver; andmemory, communicatively coupled to the at least one processor, storing instructions executable by the at least one processor individually or in any combination to cause the UDM entity to:receive, from an access and mobility management function (AMF) entity of a second public land mobile network (PLMN) of a hosting operator via the at least one transceiver, a request message for a registration procedure, wherein the request message includes a PLMN identifier (ID) of a first PLMN of a participating operator; andtransmit, to the AMF entity via the at least one transceiver, subscription data for a user equipment (UE) based on the PLMN ID of the first PLMN.13.The UDM entity of claim 12,wherein the request message further includes a PLMN ID of the second PLMN of the hosting operator.14.The UDM entity of claim 13, wherein the instructions further cause the UDM entity to:identify, based on the PLMN ID of the second PLMN, that the UE is registered in indirect network sharing.15.The UDM entity of claim 12,wherein the first PLMN of the participating operator is selected by the UE.

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