Network structure supporting multicast and broadcast services in mobile communication network and service provision method

Abstract

The present disclosure relates to a communication method and system for integrating a fifth generation (5G) communication system supporting a higher data rate than a fourth generation (4G) system with Internet of Things (IoT) technology. The present disclosure can be applied to smart services based on 5G communication technology and IoT-related technologies, such as smart homes, smart buildings, smart cities, smart cars, connected cars, healthcare, digital education, smart retail, security and safety services. According to the present disclosure, MBS services for flexible and dynamic MBS service scenarios become possible in the next generation wireless communication system.

Description

Technical Field

[0001] In order to send the same data to multiple terminals concentrated in a specific area in a mobile communication network, data can be sent to each terminal by unicast. However, for resource efficiency, data / services need to be provided by multicast / broadcast. For example, a method is needed to send data to multiple terminals concentrated in a specific area by multicast / broadcast of a TV / audio service, a vehicle-to-everything communication (V2X) service, or a large-scale cellular IoT (CIoT) service, and the present disclosure relates to a network configuration scheme for supporting multicast / broadcast services (MBS) by defining network functions (NFs) or NF services therefor, exposing corresponding NFs or NF services, discovering them, selecting them, etc. Background Art

[0002] In order to meet the increasing demand for wireless data services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or quasi-5G communication systems. Therefore, 5G or quasi-5G communication systems are also called "super 4G networks" or "post-LTE systems". In order to achieve higher data rates, it is considered to implement 5G communication systems in higher frequency (millimeter wave) bands (for example, 60GHz bands). In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple input multiple output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming and massive antenna technology are discussed in 5G communication systems. In addition, in 5G communication systems, system network improvements are being developed based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, collaborative communications, coordinated multi-point (CoMP), receiving-end interference elimination, etc. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coded modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0003] The Internet, a human-centered connected network in which humans generate and consume information, is now evolving into the Internet of Things (IoT), in which distributed entities such as things exchange and process information without human intervention. The Internet of Things (IoE), which combines IoT technology and big data processing technology through connection with cloud servers, has emerged. Since IoT implementation requires technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology" and "security technology", sensor networks, machine-to-machine (M2M) communication, machine type communication (MTC), etc. have been studied recently. This IoT environment can provide smart Internet technology services to create new value for human life by collecting and analyzing data generated between connected things. IoT can be applied to various fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances and advanced medical services through the integration and combination of existing information technology (IT) with various industrial applications.

[0004] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine type communications (MTC), and machine-to-machine (M2M) communications can be implemented through beamforming, MIMO, and array antennas. The application of cloud radio access networks (RANs), which are the above-mentioned big data processing technologies, can also be regarded as an example of the convergence between 5G technologies and IoT technologies.

[0005] Meanwhile, there is a demand for a service of transmitting the same data to a plurality of terminals in a next generation wireless communication system. Summary of the invention

[0006]

Technical issues

[0007] In order to send the same data to multiple terminals concentrated in a specific area in a mobile communication network, it is necessary to provide data / services through multicast / broadcast. For example, a method is needed to transmit data to multiple terminals concentrated in a specific area through multicast / broadcast of a TV / audio service, a V2X service, or a large-scale CIoT service. The present disclosure relates to a network configuration scheme for supporting a multicast / broadcast service (MBS) by defining a network function (NF) or NF service for it, exposing the corresponding NF or NF service, discovering them, selecting them, etc.

[0008] Typically, a broadcast multicast service center (BM-SC) and MBMS-GW are introduced into the core network in an LTE network, and a multi-cell / multicast coordination entity (MCE) is introduced into E-UTRAN to support multicast / broadcast services. At the same time, a 5GS MBS network configuration scheme is required to support 5GS multicast / broadcast services, improve deployment and operation flexibility, and dynamically adjust multicast / broadcast services. The present disclosure introduces a service disclosure scheme for NF or NF services supporting MBS services, as well as a discovery and selection scheme for NF or NF services.

[0009]

Technical solution

[0010] According to an embodiment of the present disclosure, a method for controlling a first entity in a wireless communication system may include: receiving information about a data service of a session of a multicast / broadcast service (MBS); receiving Internet Protocol (IP) address information of a second entity; generating context information for managing the MBS session; and establishing a control session for the second entity based on the IP address information and context information of the second entity.

[0011] Meanwhile, a first entity in a wireless communication system may include a transceiver and a controller, the controller being configured to control the transceiver to receive information about a data service of a session of a multicast and broadcast service (MBS), and to receive Internet Protocol (IP) address information of a second entity, generate context information for managing the MBS session, and perform control based on the IP address information and the context information of the second entity to establish a control session of the second entity.

[0012]

Beneficial Effects

[0013] The present disclosure implements MBS services regarding flexible and dynamic MBS service scenarios in 5GS. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1A and Figure 1B The 5GS structure of the MBS according to an embodiment of the present disclosure is illustrated;

[0015] Figure 2 The process of generating an MBS session according to an embodiment of the present disclosure is illustrated;

[0016] Figure 3 FIG. 1 illustrates a process of registering a profile in an NRF by an MBS-related entity according to an embodiment of the disclosure;

[0017] Figure 4 illustrates a process in which an AF (AS or content provider) selects an appropriate BM-CPF to provide an MBS service according to an embodiment of the present disclosure;

[0018] Figure 5illustrates a process in which a BM-CPF selects an appropriate BM-UPF to provide an MBS service according to an embodiment of the present disclosure;

[0019] Figure 6 illustrates a process in which a BM-CPF selects an appropriate SMF to provide an MBS service according to an embodiment of the present disclosure;

[0020] Figure 7 A process in which the SMF selects an appropriate UPF to provide an MBS service according to an embodiment of the present disclosure is illustrated;

[0021] Figure 8 A process in which an SMF selects an appropriate AMF to provide an MBS service according to an embodiment of the present disclosure is illustrated;

[0022] Fig. 9 illustrates a process in which an SMF selects an appropriate NG-MCE to provide an MBS service according to an embodiment of the present disclosure;

[0023] Fig.10 The structure of a first entity in a wireless communication system according to an embodiment of the present disclosure is illustrated; and

[0024] Fig.11 The diagram illustrates a structure of a second entity in a wireless communication system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] Hereinafter, the working principle of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description of the present disclosure, when it is determined that a detailed description of a known function or configuration contained herein may make the subject matter of the present invention unnecessarily unclear, the description will be omitted. The terms to be described below are terms defined in consideration of the functions in the present disclosure, and may differ depending on the user, user intent, or custom. Therefore, the definition of the terms should be based on the content of the entire specification.

[0026] For the same reason, in the accompanying drawings, some elements may be exaggerated, omitted or schematically illustrated. In addition, the size of each element does not fully reflect the actual size. In the accompanying drawings, the same or corresponding elements have the same reference numerals.

[0027] By referring to the embodiments described in detail below in conjunction with the accompanying drawings, the advantages and features of the present disclosure and the methods for achieving these advantages and features will become apparent. However, the present disclosure is not limited to the embodiments described below, but can be implemented in various different forms. The following embodiments are provided only to fully disclose the present disclosure and inform those skilled in the art of the scope of the present disclosure, and the present disclosure is limited only by the scope of the attached claims. Throughout the specification, the same or similar reference numerals represent the same or similar elements.

[0028] In this article, it should be understood that each block of the flowchart diagram and the combination of blocks in the flowchart diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device create a method for implementing the specified function in the flowchart block. These computer program instructions can also be stored in a computer-usable or computer-readable memory, which can instruct the computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-usable memory or the computer-readable memory produce an article of instruction components including the functions specified in one or more flowchart blocks. The computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are performed on the computer or other programmable device to produce a computer-implemented process so that the instructions executed on the computer or other programmable device provide steps for implementing the specified functions in one or more flowchart blocks.

[0029] In addition, each block of the flowchart diagram may represent a module, segment or portion of code, which includes one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions recorded in the blocks may appear out of order. For example, two blocks shown in succession may actually be executed substantially simultaneously, or may sometimes be executed in the reverse order, depending on the functions involved.

[0030] As used herein, "unit" refers to a software element or hardware element that performs a predetermined function, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). However, the meaning of "unit" is not always limited to software or hardware. "Unit" can be constructed to be stored in an addressable storage medium, or to execute one or more processors. Therefore, "unit" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, programs, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays and parameters. The elements and functions that "unit" provides can be combined into a smaller number of elements or "units", or divided into a larger number of elements or "units". In addition, these elements and "units" may be implemented as reproducing one or more CPUs in a device or a secure multimedia card. In addition, "unit" in an embodiment may include one or more processors.

[0031] Hereinafter, the working principle of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description of the present disclosure, when it is determined that a detailed description of a known function or configuration contained herein may make the subject matter of the present invention unnecessarily unclear, the description will be omitted. The terms to be described below are terms defined in consideration of the functions in the present disclosure and may differ according to the user, user intention or custom. Therefore, the definition of the terms should be based on the content of the entire specification. In the following description, a base station is an entity that allocates resources to a terminal and may be at least one of a gNode B, an eNode B, a node B, a base station (BS), a wireless access unit, a base station controller, and a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. Of course, examples of base stations and terminals are not limited thereto. The following description of the present disclosure is directed to a technology for a terminal in a wireless communication system to receive broadcast information from a base station. The present disclosure relates to a communication technology and a system thereof for integrating IoT technology with a fifth generation (5G) communication system designed to support higher data transmission rates than a fourth generation (4G) system. The present disclosure can be applied to smart services based on 5G communication technology and IoT-related technology (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail business, security and safety-related services, etc.).

[0032] As used in the following description, for convenience, illustratively, terms referring to broadcast information, terms referring to control information, terms referring to communication coverage, terms referring to state changes (e.g., events), terms referring to network entities, terms referring to messages, terms referring to device elements, etc. are used. Therefore, the present disclosure is not limited by the following terms, and other terms with equivalent technical meanings may be used.

[0033] As used in the following description, for convenience, terms for identifying access nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc. are illustratively used. Therefore, the present disclosure is not limited by the following terms, and other terms with equivalent technical meanings may be used.

[0034] In the following description of the present disclosure, for the convenience of description, the terms and names defined in the 5G system standard will be used. However, the present disclosure is not limited to these terms and names, and can be applied to systems conforming to other standards in the same manner.

[0035] first, Figure 1A and Figure 1B The diagram illustrates the structure of a cellular system for MBS services, for example, a 5GS structure according to an embodiment of the present disclosure.

[0036] To support MBS services in 5GS, the MBS cellular system is configured with the following network functions and services.

[0037] In the case where an application server such as a V2X application server or a CIoT application server or an MCPTT application or content provider such as a TV or audio service provider, a streaming video service provider, etc. requests an MBS service, the cellular system may include a broadcast / multicast control plane function (BM-CPF) and a broadcast / multicast user plane function (BM-UPF), the broadcast / multicast control plane function (BM-CPF) being a network function for managing the corresponding MBS service session and controlling the corresponding MBS service business, and the broadcast / multicast user plane function (BM-UPF) being an MBS service media anchor in 5GS, for receiving media from an AS or a content provider, and processing media business under the control of the BM-CPF. The interface between the BM-CPF and the BM-UPF is called an Nxxx interface. The BM-CPF and the BM-UPF may be integrated into one entity or one NF. For example, the BM-CPF may be a first entity and the BM-UPF may be a second entity.

[0038] Through the BM-CPF and BM-UPF, MBS sessions can be managed and service traffic can be generated. When the service traffic is transmitted to the terminal via multicast / broadcast, the corresponding traffic can be managed by performing the allocation of MBS PDU sessions. The control functions or services used to generate MBS contexts for MBSPDU sessions, manage MBS PDU sessions, and transmit the traffic of MBS PDU sessions to NG-RAN via IP multicast are collectively referred to as Multimedia Broadcast Multicast Service Gateway Control Plane (MBMS-GW-C) services. The MBMS-GW-C service can be integrated into an existing SMF for managing unicast PDU sessions and configured as an SMF with MBS PDU session control functions, or it can be configured as a separate NF. An NF that is configured solely with the MBMS-GW-C service is referred to as a multicast / broadcast session management function (MB-SMF) in this document.

[0039] In addition, services for delivering services received from the BM-UPF according to the MBS context of the MBS PDU session to the NG-RAN that performs multicast / broadcast according to the MBMS-GW-C service through IP multicast are collectively referred to as Multimedia Broadcast Multicast Service Gateway User Plane (MBMS-GW-U) services. The MBMS-GW-U service can be integrated into the existing UPF to perform processing of unicast PDU sessions and configured as a UPF with the function of delivering MBS services to the appropriate NG-RAN through IP multicast, or can be configured as a separate NF. An NF that is configured separately using only the MBMS-GW-U service is referred to as a multicast / broadcast user plane function (MB-UPF) in this document.

[0040] The MBMS-GW-C service uses the N4-MBS interface to control the MBMS-GW-U service.

[0041] When describing the embodiments of the present disclosure, for convenience, MBMS-GW-C and MBMS-GW-U are mainly described as SMF and UPF, respectively, but if necessary, in order to avoid confusion, it is also described whether their use is for unicast or multicast / broadcast, or whether both are supported.

[0042] The MBS session service is transmitted from the MBMS-GW-U (or UPF or MB-UPF) to the NG-RAN. For example, the MBS session service is transmitted to the NG-RAN using IP multicast. Here, the tunnel between the MBMS-GW-U (or UPF or MB-UPF) and the NG-RAN is called an M1 tunnel.

[0043] To establish an M1 tunnel, MBMS-GW-C (or SMF or MB-SMF) sends a control message to NG-RAN through the Next Generation Multi-Cell Coordination Entity (NG-MCE) or directly to NG-RAN.

[0044] Here, the communication with the MBMS-GW-C may be performed via the AMF, which has an M3 connection with the NG-MCE or NG-RAN, as Figure 1A Optionally, Figure 1B As shown, the MBMS-GW-C can directly transmit the control message to the appropriate NG-MCE via the M3 connection, and the NG-MCE can transmit the received control message of the MBMS-GW-C to the NG-RAN via the M2 connection. Optionally, the MBMS-GW-C can send the control message directly to the NG-RAN via the M3 connection.

[0045] According to an embodiment of the present disclosure, the MBS service is performed through the following procedures: First, when the terminal is notified that the MBS service is available, the terminal that wishes to receive the service may perform service registration for the MBS service when necessary, and may perform a procedure for acquiring relevant parameters required to receive the service.

[0046] Meanwhile, in 5GS, a signaling procedure may be performed to generate a session for transmitting MBS data, and to generate and manage a tunnel for sending MBS data from an MBS service provider or an application server (AS) to a base station in a corresponding area.

[0047] When MBS data arrives at the base station through the tunnel, the base station broadcasts information indicating the presence of MBS data to be sent and when / how to perform MBS data transmission, to allow terminals that have acquired MBS service parameters to know the information and broadcast MBS data according to the information.

[0048] When the MBS service is no longer performed, the generated session may be released and the tunnel allocated for the service may be removed.

[0049] Figure 2 The diagram illustrates a process for initiating an MBS session in a 5G network according to an embodiment of the present disclosure.

[0050] In operation S200, an application server (AS) or an MBS content provider may transmit information related to an MBS session data service to an MBS function of a 5GS network so as to transmit the MBS data service through the 5GS, and may obtain IP address information of a media anchor in the 5GS to which the MBS data is to be transmitted. For example, the MBS function may be a BM-CPF, or an SMF or a BMSC including an MBS service session management function, as a first entity. In addition, the media anchor may be a BM-UPF, or a UPF or a BMSC including a media source function of a BM-UPF or MBS service session, as a second entity.

[0051] For example, the role of the MBS function may be performed by a broadcast multicast control plane function (BM-CPF), a session management function (SMF) having an MBS service session management function added thereto, a broadcast multicast service center (BMSC), and the like.

[0052] In addition, for example, the role of the media anchor in 5GS can be performed by a broadcast multicast user plane function (BM-UPF), a user plane function (UPF) with a media source function of an MBS service session added to it, a broadcast multicast service center (BMSC), etc.

[0053] In operation S210, the MBS function generates an MBS context for managing the MBS service session in the 5GS and establishes a control session for the MBS media anchor in the 5GS. For example, the BM-CPF may generate an MBS context and establish a control session for the MBS media anchor in the 5GS.

[0054] In operation S220, the MBS function determines whether to perform MBS data service transmission via broadcast, multicast or unicast. The transmission method can be determined according to the density of terminals receiving MBS session services, for example, how many terminals will receive the service in the area to which the service will be broadcast / multicast, or can be determined according to whether the base station where the terminal receiving the MBS session service is located has the MBS function.

[0055] In operation S230, when it is determined that the transmission of the MBS data service occurs via broadcast / multicast, a tunnel may be generated between a base station and a media anchor located in an area where the MBS data service is to be broadcast. The tunnel between the media anchor and the base station includes a tunnel between the media anchor and the UPF for broadcast / multicast, and a tunnel between the UPF for broadcast / multicast and a base station located in an area where the data service is to be broadcast. The MBS function establishes a control session for managing the tunnel between the media anchor and the UPF for broadcast / multicast. In addition, the MBMS-GW-C (or SMF or MB-SMF) establishes a control session for managing the tunnel between the UPF for broadcast / multicast and a base station located in an area where the data service is to be broadcast.

[0056] For example, a tunnel may be generated between the BM-UPF and the NG-RAN. The tunnel may include a first tunnel between the BM-UPF and the MBMS-GW-U service, and a second tunnel between the MBMS-GW-U service and the NG-RAN. The BM-CPF may establish a control session for managing the first tunnel. In addition, the MBMS-GW-C may establish a control session for managing the second tunnel.

[0057] Meanwhile, when the BM-UPF used as a media anchor and the UPF for broadcast / multicast (e.g., MB-UPF) are implemented as one entity, the two tunnels can be configured as one and managed. Therefore, the MBS function and the MBMS-GW-C can be configured as one, and thus a control session for managing the tunnel between the media anchor and the base station is established.

[0058] On the other hand, when it is determined that the transmission of MBS data services occurs via unicast, the MBS function can allow the corresponding terminal to generate a PDU session for the data network (DN) serving the MBS, and can generate a tunnel between the media anchor and the base station to which the terminal is connected, between the base station and the UPF to which the media source function is added, or between the base station and the UPF of the MBS.

[0059] When describing the embodiments of the present disclosure, the MBS functions and services of 5GS may be referred to as BM-CPF. However, the MBS functions and services may exist in SMF, or may exist together with the user plane as BM-SC. In addition, the media anchor of 5GS is referred to as BM-UPF. However, the media anchor may exist in UPF, or may exist together with the control plane as BM-SC.

[0060] BM-CPF can make service announcements for MBS services in 5GS, manage MBS user service sessions, determine whether to send MBS data via broadcast / multicast or unicast, or manage BM-UPF as a media anchor, and therefore can receive MBS data from AS or MBS content providers and control the transmission of MBS data through 5GS.

[0061] In order to provide MBS services according to the embodiments of the present disclosure, a method is needed to expose the MBS functions and services of 5GS outside the 5GS network and for an application server (AS) or an MBS content provider to discover and select appropriate MBS functions and services.

[0062] To this end, it is necessary to register MBS functions and services in the Network Repository Function (NRF) and the Network Exposure Function (NEF), and support other Network Functions (NF) or Application Functions (AF) to discover and select MBS functions and services.

[0063] Figure 3 A process in which a network function (NF) 300 registers, updates, or deregisters a profile in an NRF 310 to provide an MBS service according to an embodiment of the present disclosure is illustrated.

[0064] NF 300 may request registration of information required for providing services and information related to NF type, NF instance ID, providing NF service name, and PLMN ID from NRF 310 through Nnrf_NFManagement_NFRegister_request message (operation S320). In addition, NRF 310 may store the profile of NF 300 (operation S330), and may notify NF 300 of the registration of the NF profile through Nnrf_NFManagement_NFRegister_response message (operation S340).

[0065] In addition, when updating the NF profile itself, NF 300 requests NRF to update the profile of NF 300 through Nnrf_NFManagement_NFUpdate_request message, including information of the service to be changed and NF instance ID or information of the service to be changed (operation S320). In addition, NRF 310 can update the profile (operation S330), and can provide notification of the update result to NF 300 through Nnrf_NFManagement_NFUpdate_response message (operation S340).

[0066] In addition, when NF 300 does not provide its own service, NF can request deregistration to NRF 310 through Nnrf_NFManagement_NFDeregister_request message, together with NF instance ID and its reason (step S320). After performing the deregistration process, NRF 310 can provide an update of the state of NR 300 as unavailable to NRF 310 (step S330), and can notify NF 300 of the update result through Nnrf_NFManagement_NFDeregister_response (operation S340).

[0067] Here, the NF 300 may be a BM-CPF, a BM-UPF, an SMF, an UPF, or an AMF as an NF for MBS service. Service related information registered / updated / deregistered in a profile of each NF will be explained.

[0068] First, when the NF 300 is a BM-CPF, the information required for service registration in the NRF 310, which enables an application function (AF), an application server (AF), or a content provider to select an appropriate BM-CPF to provide an MBS service, may include NF type = BM-CPF, NF instance ID, a provided NF service name (e.g., Nbmcpf_MBSservice, etc.), and a service ID indicating the type of MBS service that the BM-CPF can support, together with a PLMN ID, such as TV service, video service, broadcast service, IoT service, V2X service, and public safety service. Optionally, the information required for service registration may include information including more detailed service information, such as a service ID indicating a channel x TV service, a police network service in a public safety service, a firefighter network service in a public safety service, and providing IoT services for subscribers of a specific company. In addition, the information may include the coverage of MBS services that can be supported by the BM-CPF, such as an MBS service area, or part or all of a TAI list or a cell ID list. In addition, the information may include a broadcast group ID list, which is a list of terminal groups that can receive services, for example, a range of corresponding TMGIs or a TMGI list. In addition, the information may include information that the BM-CPF can support, such as DNN and network slice information (e.g., S-NSSAI, NW slice instance ID).

[0069] A method of discovering and selecting an appropriate BM-CPF by using information fragments stored in a profile of the BM-CPF of the NRF 310 is described in another embodiment.

[0070] Meanwhile, when the NF 300 is a BM-UPF, the information required for service registration in the NRF 310, which allows the BM-CPF to select a suitable BM-UPF so that the 5GS receives the MBS service provided by the application function (AF), the application server (AF) or the content provider to provide the role as a media anchor in the 5GS, may include NF type = BM-UPF, NF instance ID, the provided NF service name (e.g., Nbmupf_MBSservice, etc.), and a service ID indicating the MBS service type that the BM-UPF can support, and a PLMN ID, such as TV service, video service, radio service, IoT service, V2X service, and public safety service. Optionally, the information may include information containing more detailed service information, such as a service ID indicating a channel x TV service, a police network service in a public safety service, a firefighter network service in a public safety service, and providing IoT services for subscribers of a specific company. In addition, the information may include the MBS service coverage that can be supported by the BM-CPF, such as an MBS service area, or part or all of a TAI list, a cell ID list, or a DNAI. In addition, the information may include a broadcast group ID list, which is a list of terminal groups that can receive the service, for example, a range of corresponding TMGIs or a TMGI list. In addition, the information may include information that the BM-CPF can support, such as network slicing information (e.g., S-NSSAI, NW slice instance ID).

[0071] A method in which the BM-CPF discovers and selects an appropriate BM-UPF by using information fragments stored in the profile of the BM-UPF of the NRF 310 is described in another embodiment.

[0072] When the NF 300 is an SMF, the information required for registering the service in the NRF 310, which enables the BM-CPF to manage the MBS session and select the SMF suitable for performing control, such as generating / modifying / cancelling the tunnel through which the corresponding MBS service is sent, may include NF type = SMF, NF instance ID, provided NF service name (e.g., Nsmf_PDUSession, Nsmf_Multicast&BroadcastPDUSession, etc.), and service ID, which together with the PLMN ID indicates whether the SMF can support IP multicast, whether the SMF can support broadcast / multicast transmission method, whether the SMF can support unicast transmission method, the IP version that can be supported, the MBS service type that the SMF can support, such as TV service, video service, radio service, IoT service, V2X service, and public safety service. Optionally, the information may include information containing more detailed service information, such as service ID indicating channel x TV service, police network service in public safety service, firefighter network service in public safety service, and providing IoT service for subscribers of a specific company. In addition, the information may include the MBS service coverage that can be supported by the BM-CPF, for example, the MBS service area, or part or all of the TAI list, cell ID list or DNAI. In addition, the information may include a broadcast group ID list, which is a list of terminal groups that can receive the service, for example, a range of corresponding TMGIs or a TMGI list. In addition, the information may include information that the SMF can support, such as network slice information (e.g., S-NSSAI, NW slice instance ID). In addition, the information may include information that the SMF can support, such as network slice information (e.g., S-NSSAI, NW slice instance ID). In addition, the information may include information related to whether the SMF supports switching and steering functions between broadcast / multicast transmission methods and unicast transmission methods.

[0073] In another embodiment, a method of discovering and selecting an appropriate SMF by using information fragments stored in the profile of the SMF of the NRF 310 is described.

[0074] When NF 300 is a UPF, the information required for registering the service in NRF 310, which allows SMF to select an appropriate UPF corresponding to one end of the tunnel for sending MBS services according to the MBS session, may include NF type = UPF, NF instance ID, provided NF service name (e.g., Nupf_PDUSession, Nupf_Multicast&BroadcastPDUSession, etc.), and together with PLMN ID, whether UPF can support IP multicast, whether UPF can support broadcast / multicast transmission method, whether UPF can support unicast transmission method, supported IP version, MBS service coverage that UPF can support, for example, MBS service area, or part or all of TAI list, cell ID list or DNAI. In addition, the information may include information that UPF can support, such as network slice information (e.g., S-NSSAI, NW slice instance ID). In addition, the information may include information related to whether UPF supports switching and steering functions between broadcast / multicast transmission method and unicast transmission method.

[0075] In another embodiment, a method of discovering and selecting an appropriate UPF by using pieces of information stored in the profile of the UPF of the NRF is described.

[0076] When NF 300 is an AMF, the information required for service registration in NRF 310 enables SMF to control and manage the tunnel for sending the corresponding MBS service according to the MBS session, to select the appropriate AMF to relay control messages between SMF and NG-RAN (e.g., NG multi-cell coordination entity (MCE), eNB or gNB), so as to send QoS / policy information for tunnel establishment and MBS service to NG-RAN as one end of the tunnel, etc., which may include NF type = AMF, NF instance ID, provided NF service name (e.g., Namf_Communication_N1N2MessageTransfer, Namf_Communication_M3MessageTransfer, etc.), whether AMF establishes M3 interface - which is the interface between MBS and NG-MCE or NG-RAN - and PLMN ID, GUAMI information of AMF, MBS service coverage that AMF can support, for example, MBS service area, or part or all of TAI list or cell ID list. In addition, the information may include information that AMF can support, such as network slicing information (e.g., S-NSSAI, NW slice instance ID), etc.

[0077] In another embodiment, a method of discovering and selecting an appropriate AMF by using information fragments stored in the AMF profile of the NRF 310 is described.

[0078] When NF 300 is NG-MCE, the information required for service registration in NRF, which enables SMF to control and manage the tunnel for sending the corresponding MBS service according to the MBS session, so as to select the appropriate NG-MCE when SMF directly sends a control message to NG-MCE or NG-RAN, so as to send QoS / policy information for tunnel establishment and MBS service to NG-RAN as one end of the tunnel, etc., may include NF type = NG-MCE, NF instance ID, provided NF service name (e.g., Nmce_Communication_M3 MessageTransfer, etc.), a list of NG RANs to which NG-MCE is connected through M2, which is an interface for MBS, and PLMN ID, MBS service coverage that NG-MCE can support, for example, MBS service area, or part or all of TAI list or cell ID list. In addition, the information may include information that NG-MCE can support, such as network slice information (e.g., S-NSSAI, NW slice instance ID).

[0079] A method of discovering and selecting an appropriate NG-MCE by using information fragments stored in the profile of the NG-MCE of the NRF 310 is described in another embodiment.

[0080] at the same time, Figure 4 A process of selecting an appropriate BM-CPF 430 in order to provide an MBS service by an AF 400, such as an AS or a content provider, according to an embodiment of the present disclosure is illustrated.

[0081] AF 400 may include information of MBS service in Nnef_MBSservice_create request message, and send the message to NEF 410 that exposes MBS service capacity to provide MBS service (operation S440). The information of MBMS service may include information about service type. Specifically, the information of MBS service may include service ID indicating MBS service type, such as TV service, video service, radio service, IoT service, V2X service, public safety service, or more detailed service information. For example, detailed service information may include service ID indicating channel x TV service, police network service in public safety service, firefighter network service in public safety service, and IoT service for subscribers of a specific company. In addition, the information may include MBS service coverage in which MBS service is performed, for example, MBS service area, or area information of part or all of TAI list, cell ID list, or actual map. In addition, the information may include broadcast group ID list, which is a list of terminal groups that can receive services, for example, a range of corresponding TMGI or TMGI list. In addition, characteristics of the traffic generated due to the MBS service, such as all or part of the 5QI, resource type (e.g., GBR, delay critical GBR, or non-GBR), maximum bit rate, guaranteed bit rate, maximum delay tolerance, maximum packet loss rate, priority, and maximum data burst size, may be included as QoS information.

[0082] After receiving the message, the NEF 410 may send a Nnrf_NFDiscovery_Request request message to the NRF 420 in order to select an appropriate BM-CPF 430 (operation S445). Here, the Nnrf_NFDiscovery_Request request message may include target NF service = Nbmcpf_MBSservice, NF type of target NF = BM-CPF, NF type of NF service consumer = AF, and ID information of AF 400. In addition, the Nnrf_NFDiscovery_Request request message may include the MBS service ID received from AF400, the MBS service coverage, and part or all of the information about the terminal group list capable of performing service reception. In addition, the Nnrf_NFDiscovery_Request request message may include the corresponding network slice information (e.g., S-NSSAI) received from AF 400 or found through the information received from AF400.

[0083] If the AF 400 belongs to a trusted domain of the 5GS, the AF 400 may request discovery of an appropriate BM-CPF 430 by sending an Nnrf_NFDiscovery_Request request message directly to the NRF 420 without passing through the NEF 410.

[0084] Upon receiving the message, the NRF 420 may recognize that BM-CPF discovery is allowed for the NF or AF (operation S450). In addition, the NRF 420 may search / discover a suitable BM-CPF from the profiles of the BM-CPFs registered in the NRF 420, and may transmit the information of the discovered BM-CPF to the NEF 410 through the Nnrf_NFDiscovery_Request response message (operation S455). As a method of searching / discovering a suitable BM-CPF 430, the NRF 420 may look for a profile of the BM-CPF 430 that is determined to be most consistent with all or part of the information included in the Nnrf_NFDiscovery_Request request message. The information of the BM-CPF included in the Nnrf_NFDiscovery_Request response message may include NF Type = BM-CPF, NF Instance ID, FQDN or IP address of the NF instance, and a service instance list. In addition, the information of the BM-CPF may include NF load information of the BM-CPF or part or all of the MBS service ID, MBS service coverage, TAI list, PLMN ID, and S-NSSAI.

[0085] The NEF 420 may send the MBS service request requested by the AF 400 to the selected BM-CFP among the discovered BM-CPFs through the Nbmcpf_MBSservice_create request message (operation S460). In addition, as a response thereto, the NEF 420 may receive a Nbmcpf_MBSservice_create response message from the BM-CPF (operation S465). The Nbmcpf_MBSservice_create response message may include information about the NF that the BM-CPF 430 uses as a media anchor within the 5GS, for example, information about the FQDN or IP address of the BM-UPF. In addition, the Nbmcpf_MBSservice_create response message may include information about the transmission method of the MBS service selected by the BM-CPF 430.

[0086] If an existing MBS service is not being performed in the process of transmitting the information of the MBS service to the NEF 410, which exposes the MBS service capability of the MBS service, the AF 400 may include the information of the MBS service in the Nnef_MBSservice_create request message and transmit it as described above to allow the BM-CPF 430 to newly generate the MBS service. However, if the existing MBS service is being performed, the information of the existing MBS service is transmitted through the Nnef_MBSservice_update request message in operation S440, and the corresponding BM-CPF 430 may request the update of the existing MBS service. Alternatively, the corresponding BM-CPF 430 may request the deletion of the existing MBS service through the Nnef_MBSservice_delete request message, and may perform an update request or a deletion request according to the request through operations S460, S465, and S470.

[0087] like Figure 4 As shown, in the process of selecting an appropriate BM-CPF 430 by the AF (AS or content provider) 400 to provide MBS services, when the AF 400 belongs to the trusted domain of the 5GS, the AF 400 may directly send the message sent in operation S445 to the NRF 420 without passing through the NEF 410, instead of sending the message sent in operation S440. In addition, in response thereto, the NRF 420 may directly send the message sent in operation S455 to the AF 400, so as to enable the AF 400 to directly select an appropriate BM-CPF 430 based on the response of the NRF 420. Here, the AF 400 may omit operations S440 and S470, and discover / select the BM-CPF 430 through operations S445, S450, and S455. In addition, the AF 400 may directly request the MBS service through the BM-CPF 430 through operations S460 and S465.

[0088] Furthermore, in the case where a service communication proxy (SCP) is used in 5GS, if message transmission to the SCP occurs, instead of sending messages directly between the AF 400, NEF 410, or BM-CPF 430, messaging between NFs can occur in a method where the SCP searches / discovers the destination based on information that the NRF 420 or the SCP itself has, and transmits the message to the appropriate NF to allow it to be processed.

[0089] at the same time, Figure 5 A process in which the BM-CPF 500 selects an appropriate BM-UPF 520 to provide an MBS service according to an embodiment of the present disclosure is illustrated.

[0090] In order to select an appropriate BM-UPF 520, in operation S530, the BM-CPF 500 sends a Nnrf_NFDiscovery_Request request message to the NRF 510. Here, the Nnrf_NFDiscovery_Request request message may include target NF service = Nbmupf_MBSservice, NF type of the target NF = BM-UPF, PLMN ID, MBS service ID indicating the type of MBS service that the BM-CPF wishes to provide, MBS service coverage in which the service will be performed, for example, an MBS service area or TAI list, a cell ID list or part or all of a DNAI, and a broadcast group ID list, which is a list of receiving terminal groups targeted for the service, for example, a range of corresponding TMGIs or a TMGI list. Optionally, the message may include some or all of the information belonging to the BM-CPF 500, such as network slice information (e.g., S-NSSAI, NW slice instance ID).

[0091] After receiving the message, the NRF 510 may recognize that BM-UPF discovery is allowed for NF (operation S540). In addition, the NRF 510 may search / discover an appropriate BM-UPF 520 from the profile of the BM-UPF 520 registered in the NRF 510, and may transmit the information of the discovered BM-UPF to the BM-CPF 500 through the Nnrf_NFDiscovery_Request response message (operation S550). The method of searching / discovering an appropriate BM-UPF 520 may be a method of finding a profile of a BM-CPF that is determined to be most consistent with all or part of the information sent by including in the Nnrf_NFDiscovery_Request request message. The BM-UPF information included in the Nnrf_NFDiscovery_Request response message may include NF type = BM-UPF, NF instance ID, FQDN or IP address of the NF instance, and a service instance list. In addition, the information of BM-UPF may include NF load information of BM-UPF or part or all of MBS service ID, MBS service area, TAI list, PLMN ID, S-NSSAI and DNAI.

[0092] The BM-CPF 500 may transmit an Nbm_Session_Establishment request message to a selected BM-UFP among the discovered BM-UPFs (operation S560). The BM-UPF 520 may send an Nbm_Session_Establishment response message to the BM-CPF 500 in response to the request, while establishing a control session for controlling the MBS service session traffic between the BM-CPF 500 and the BM-UPF 520 (operation S570). The Nbm_Session_Establishment response message may include information about the NF used as a media anchor in the 5GS, for example, the FQDN or IP address of the BM-UPF.

[0093] As described above, when the control session between the BM-CPF 500 and the BM-UPF 520 is not established, a new session is established by exchanging Nbm_Session_Establishment request / response messages as described in operations S560 and S570. However, if the BM-CPF 500 already has a control session with the BM-UPF 520, in operation S560, an update of an existing MBS service is requested through an Nbm_Session_modification request message, or the corresponding BM-CPF may request the release of the existing control session through an Nbm_Session_release request message. In addition, an update request or a release request may be performed according to the request through operation S570.

[0094] In the case of using a Service Communication Agent (SCP) in 5GS, if the BM-CPF 500 sends the message to the SCP, rather than sending the message directly to the BM-UPF 520, messaging between NFs may occur in a method where the SCP searches / discovers the destination based on information possessed by the NRF or the SCP itself, and passes the message to the appropriate NF to allow it to be processed.

[0095] at the same time, Figure 6 A process in which the BM-CPF 600 selects an appropriate SMF to provide an MBS service according to an embodiment of the present disclosure is illustrated.

[0096] The BM-CPF 600 may send the MBS service that has reached the media anchor such as the BM-UPF to an appropriate GW or UPF, and may send it to the terminal via multicast or broadcast. Optionally, the BM-CPF 600 may send an Nnrf_NFDiscovery_Request request message to the NRF 610 to select an SMF that is used to control the NF and GW of the session so as to send the MBS service service to the terminal via unicast (operation S630). Here, the Nnrf_NFDiscovery_Request request message may include target NF service = Nsmf_PDUSession, Nsmf_Multicast&BroadcastPDUSession, NF type of target NF = SMF, PLMN ID, an indicator indicating whether only MBS session services via broadcast / multicast transmission are supported or not only MBS session services via broadcast / multicast transmission but also MBS session services via unicast transmission are supported, IP version, MBS service ID indicating the type of MBS service that BM-CPF wishes to provide, MBS service coverage in which the service will be performed, for example, MBS service area, TAI list, cell ID list or DNAI, and part or all of the broadcast group ID list, the broadcast group ID list is a list of receiving terminal groups targeted for the service, for example, a range or TMGI list of corresponding TMGIs. Optionally, the message may include some or all information belonging to the SMF, such as network slice information (e.g., S-NSSAI, NW slice instance ID).

[0097] After receiving the message, the NRF 610 may recognize that SMF discovery is allowed for NF, and search / discover an appropriate SMF 620 from the profiles of the SMFs registered in the NRF 610 (operation S640), and may transmit the information of the discovered SMF to the BM-CPF 600 through the Nnrf_NFDiscovery_Request response message (operation S650). As a method of searching / discovering an appropriate SMF 620, a method of finding a profile of an SMF determined to be most consistent with all or part of the information sent by including in the Nnrf_NFDiscovery_Request request message may be used. The information of the SMF included in the Nnrf_NFDiscovery_Request response message may include NF type=SMF, NF instance ID, FQDN or IP address of the NF instance, service instance list, whether only broadcast / multicast is supported, whether not only broadcast / multicast but also unicast transmission is supported, whether the SMF supports switching between unicast and broadcast / multicast, and whether the SMF supports steering between unicast and broadcast / multicast. In addition, the information of SMF may include NF load information of SMF or part or all of MBS service ID, MBS service area, TAI list, PLMN ID, S-NSSAI and DNAI.

[0098] The BM-CPF 600 may transmit an Nbm_Session_Establishment request message to a selected SMF among the discovered SMFs by (operation S660). The request message may include the FQDN or IP address of the BM-UPF and a tunnel ID value, which is used to transmit the corresponding MBS service session from the BM-UPF, and may also include an MBS session ID for managing the MBS session. In addition, the message may include an indicator indicating that the MBS session service is sent via broadcast / multicast. In addition, the message may include an indicator indicating whether the SMF 620 allows switching or redirection of the MBS session service between unicast and broadcast / multicast. After receiving the request message, the SMF 620 may generate an MBS PDU session and an SM context in order to control the MBS session. The MBS PDU session ID may be allocated by the BM-CPF and included in the request message, or the SMF that has received the request message may directly allocate the MBS PDU session ID. In addition, the SMF may select an appropriate UPF to generate a tunnel between the BM-UPF and the selected UPF, and may include the FQDN of the corresponding UPF or tunnel information such as an IP address and a tunnel ID in the Nsmf_MBSsession_CreateSM context response message and send it to the BM-CPF 600 (operation S670). In addition, when the BM-CPF 600 allows switching or steering between unicast and broadcast / multicast for MBS session services, information about whether the corresponding session service is sent via unicast or broadcast / multicast may be included in the response message, and whenever the transmission method is changed, information about the changed transmission method may be transmitted to the BM-CPF 600.

[0099] If SMF 620 already has an SM context for the corresponding MBS session in operations S660 and S670, instead of Nsmf_MBSsession_CreateSMcontext, as the Nsmf_MBSsession_modifySMcontext service, the MBS PDU session SMcontext can be modified through the Nsmf_MBSsession_modifySMcontext request message and the Nsmf_MBSsession_modifySMcontext response message, or instead of Nsmf_MBSsession_CreateSContext, as the Nsmf_MBSsession_releaseSMcontext service, the MBS PDU session SMcontext can be released through the Nsmf_MBSsession_releaseSMcontext request message and the Nsmf_MBSsession_releaseSMcontext response message.

[0100] In case of using Service Communication Agent (SCP) in 5GS, if the message is transferred to SCP, instead of sending the message directly between BM-CPF and SMF, the messaging between NFs can happen in a method where SCP searches / discovers the destination based on the information possessed by NRF or SCP itself, and passes the message to the appropriate NF to allow it to be processed.

[0101] Figure 7 The diagram illustrates a process in which the SMF 700 selects an appropriate UPF to send an MBS service according to an embodiment of the present disclosure.

[0102] SMF 700 may send an Nnrf_NFDiscovery_Request request message to NRF 710 in order to control the session so as to send the MBS service traffic that has reached the media anchor, such as BM-UPF, to the appropriate UPF 720 and send it to the terminal via multicast or broadcast or by unicast (operation S730). Here, the Nnrf_NFDiscovery_Request request message may include target NF service = Nupf_PDUSession or Nupf_Multicast&BroadcastPDUSession, NF type of the target NF = UPF, PLMN ID, an indicator indicating whether only MBS session services are supported via broadcast / multicast transmission, or whether MBS session services are supported not only via broadcast / multicast but also via unicast transmission, IP version, MBS service ID indicating the type of MBS service that the SMF wishes to provide, MBS service coverage in which the service will be performed, for example, MBS service area, or part or all of a TAI list, a cell ID list, or a DNAI, and a broadcast group ID list, which is a list of receiving terminal groups targeted for the service, for example, a range of corresponding TMGIs or a TMGI list. Optionally, the message may include some or all of the information belonging to UPF 720, such as network slice information (e.g., S-NSSAI, NW slice instance ID).

[0103] In the target NF service, when SMF 700 sends the corresponding MBS session service via unicast, the target NF service can be configured as target NF service = Nupf_PDUSession. On the other hand, when SMF 700 sends the corresponding MBS session service via broadcast / multicast, the target NF service can be configured as target NF service = Nupf_Multicast&BroadcastPDUSession. In addition, in the case of unicast transmission, an indicator indicating that the MBS session service is only sent via unicast can be used, or an indicator indicating that both sending via unicast and sending via broadcast / multicast are supported can be used. On the other hand, when the MBS session service is sent via multicast, an indicator indicating that the MBS session service is only sent via broadcast / multicast can be used, or an indicator indicating that both sending via unicast and sending via broadcast / multicast are supported can be used. Upon receiving the message, the NRF 710 may recognize that UPF discovery is allowed for NF, and search / discover an appropriate UPF from the profiles of the UPFs registered in the NRF 710 (operation S740), and may transmit information of the discovered UPF to the SMF 700 through the Nnrf_NFDiscovery_Request response message (operation S750). As a method of searching / discovering an appropriate UPF 720, a method of finding a profile of a UPF that is determined to be most consistent with all or part of the information sent by including in the Nnrf_NFDiscovery_Request request message may be used. The information of the UPF included in the Nnrf_NFDiscovery_Request response message may include NF type=UPF, NF instance ID, FQDN or IP address of the NF instance, a list of service instances, information indicating whether only broadcast / multicast is supported, whether not only broadcast / multicast but also unicast transmission is supported, whether only transmission via unicast is supported, whether the UPF 720 supports switching between unicast and broadcast / multicast, or whether the UPF 720 supports steering between unicast and broadcast / multicast. In addition, the information of the UPF may include NF load information of the UPF or part or all of the MBS service ID, MBS service area, TAI list, PLMN ID, S-NSSAI, or DNAI.

[0104] The SMF 700 may transmit an N4-MBS Session Establishment request message to the selected UFP among the discovered UPFs (operation S760). The request message may include the FQDN or IP address of the BM-UPF and a tunnel ID value, which is used to transmit the corresponding MBS service session from the BM-UPF, and may also include an MBS session ID for managing the MBS session. In addition, the request message may include an indicator indicating whether the MBS session service is sent via broadcast / multicast, via unicast, or via both broadcast / multicast and unicast. In addition, the request message may include information indicating whether the MBS session service is switched between unicast and broadcast / multicast or whether steering is supported, and if steering is determined to be supported, information indicating the method used for support. For example, when the terminal has left the broadcast / multicast service area and is identified, the MBS session service transmission is switched to unicast, or when there is a special requirement for high availability, information allowing both unicast and broadcast / multicast methods for simultaneous service transmission may be included in the request message.

[0105] After receiving the request message, UPF 720 generates a tunnel to send the MBS session service under the control of SMF 700. In order to generate a tunnel for BM-UPF and UPF 720, the FQDN or IP address of the BM-UPF received from SMF 700 may be used. In addition, in order to configure the tunnel endpoint in UPF 720, the FQDN or IP address of UPF 720 and the tunnel ID information may be included in the N4-MBS Session Establishment response message to be transmitted to SMF 700 (operation S760). In addition, in order to generate a tunnel for IP multicast between UPF 720 and NG RAN, an IP address and a tunnel ID for IP multicast are allocated and included in the N4-MBS Session Establishment response message and transmitted to SMF 700 (operation S770). The IP address and tunnel ID values ​​for IP multicast may be directly allocated by SMF 700 and transmitted to UPF 720 through the N4-MBS Session Establishment request message.

[0106] The UPF 720 may transmit the MBS session service through an IP multicast tunnel or through a unicast tunnel under the control of the SMF 700, or may use both methods simultaneously to transmit the MBS session service to the NG-RAN.

[0107] If SMF 700 already has a corresponding control session of UPF 720 in operations S760 and S770, instead of N4-MBS Session Establishment, as N4-MBS Session Modification service, the context of UPF's MBS session can be modified through N4-MBS Session Modification request message and N4-MBS Session Modification response message, or instead of N4-MBS Session Establishment, as N4-MBSSession Release service, the context of UPF 720's MBS session can be released through N4-MBS Session Release request message and N4-MBS Session Release response message.

[0108] In case of using Service Communication Agent (SCP) in 5GS, if SMF sends messages to SCP, instead of sending messages directly between SMFs, messaging between NFs can occur in a way that SCP searches / discovers the destination based on the information possessed by NRF or SCP itself, and transmits the message to the appropriate NF to allow it to be processed.

[0109] Figure 8 The diagram illustrates a process in which the SMF 800 selects an appropriate AMF 820 to send an MBS service according to an embodiment of the present disclosure.

[0110] The SMF 800 may select an appropriate AMF 820 to transmit a control information fragment such as IP multicast information for receiving MBS service traffic to the NG-RAN located at a location to which the MBS service traffic is to be sent from the UPF via multicast. To this end, the SMF 800 may send a Nnrf_NFDiscovery_Request request message to the NRF 810 (operation S830). Here, the Nnrf_NFDiscovery_Request request message may include a target NF service = Namf_Communication_N1N2MessageTransfer or Namf_Communication_M3MessageTransfer, a NF type of the target NF = AMF, a PLMN ID, and an indicator indicating that an M3 interface is established, which is an interface between the MBS and the NG-MCE / NG-RAN. In addition, the Nnrf_NFDiscovery_Request request message may include an MBS service coverage in which the service is to be performed, for example, an MBS service area, or part or all of a TAI list, a cell ID list, a target AMF set, an area ID, or a DNAI. In addition, the request message may include a broadcast group ID list, which is a list of receiving terminal groups targeted for the service, for example, a range or a list of TMGIs corresponding to the TMGI. Optionally, the Nnrf_NFDiscovery_Request request message may include some or all of the information that the AMF should support, such as network slicing information (e.g., S-NSSAI, NW slice instance ID).

[0111] After receiving the message, the NRF 810 may recognize that AMF discovery is allowed for NF, and search / discover an appropriate AMF from the profile of the AMF registered in the NRF (operation S840), and may transmit the information of the discovered AMF to the SMF 800 through the Nnrf_NFDiscovery_Request request response message (operation S850). As a method of searching / discovering an appropriate AMF, a method of finding a profile of an AMF that is determined to be most consistent with all or part of the information sent by including in the Nnrf_NFDiscovery_Request request message may be used. For example, the NRF 810 may find out the AMF so that the NG RAN connected to the AMF through the M3 interface can fully cover the target MBS service area, and may notify the SMF 800 of this situation.

[0112] The AMF information included in the Nnrf_NFDiscovery_Request response message may include NF type = AMF, NF instance ID, FQDN, IP address or GUAMI of the NF instance, service instance list, information indicating whether to establish an M3 interface, which is an MBS interface between the AMF and the NG-MCE / NG-RAN. In addition, the AMF information included in the Nnrf_NFDiscovery_Request response message may include NF load information of the AMF, MBS service areas covered by the NG-MCE that can be connected to through the AMF, TAI list, cell ID list, DNAI or part or all of the S-NSSAI information supported by the AMF.

[0113] The SMF 800 may select an AMF 820 corresponding to the area to be served from the found AMFs, and may send a Namf_Communication_N1N2MessageTransfer request message or a Namf_Communication_M3MessageTransfer request message (operation S860). In addition, at least one AMF that has received the message may send a control message included in the request message to the connected NG-MCE, for example, IP multicast tunnel information for a base station to receive IP multicast for MBS service business. In addition, information including a message requesting the base station that has received the control message to join the IP multicast is sent to the SMF 800 through the Namf_Communication_N1N2MessageTransfer response via the AMF 820 (operation S870).

[0114] on the other hand, Fig. 9 The diagram illustrates a process in which the SMF selects an appropriate NG-MCE in a network structure to send an MBS service according to an embodiment of the present disclosure. In the network structure, the SMF directly sends the MBS control message to the NG-MCE / NG-RAN without passing through the AMF, such as Figure 1B shown.

[0115] The SMF 900 may select an appropriate NG-MCE 920 to transmit a control information fragment such as IP multicast information for receiving a service service to the NG-RAN located at a location to which the MBS service service is to be sent from the UPF by multicast. To this end, the SMF 900 may send a Nnrf_NFDiscovery_Request message to the NRF 910 (operation S930). Here, the Nnrf_NFDiscovery_Request request message may include the target NF service Nmce_Communication_M3MessageTransfer, the NF type of the target NF = NG-MCE, and the PLMN ID. In addition, the Nnrf_NFDiscovery_Request request message may include the MBS service coverage to be served, for example, the MBS service area, or part or all of the TAI list, the cell ID list, or the DNAI, and the broadcast group ID list, which is a list of receiving terminal groups targeted for the service, for example, a range of corresponding TMGIs or a TMGI list. Optionally, the Nnrf_NFDiscovery_Request request message may include part or all of the information that the NG-MCE should support, such as network slice information (e.g., S-NSSAI, NW slice instance ID).

[0116] Upon receiving the message, the NRF 910 may recognize that NG-MCE discovery is allowed for NF, and search / discover an appropriate NG MCE from the profiles of the NG MCEs registered in the NRF (operation S940), and may transmit the information of the discovered NG-MCE to the SMF 900 through the Nnrf_NFDiscovery_Request response message (operation S950). As a method of searching / discovering an appropriate NG-MCE, a method of finding a profile of an NG-MCE that is determined to be most consistent with all or part of the information sent by including in the Nnrf_NFDiscovery_Request request message may be used. For example, the NRF may find out the NG MCE so that the NG RAN connected to the NG MCE through the M2 interface can fully cover the target MBS service area, and may notify the SMF 900 of this situation.

[0117] For example, the NG-MCE information included in the Nnrf_NFDiscovery_Request response message may include NF type = NG-MCE, NF instance ID, FQDN and IP address of the NF instance, service instance list, information indicating whether to establish an M2 interface, which is an MBS interface between the NG-MCE and the NG-RAN. In addition, the NG-MCE information included in the Nnrf_NFDiscovery_Request response message may include NF load information of the NG-MCE, MBS service areas that can be covered by the NG-MCE, TAI list, cell ID list, DNAI or part or all of the S-NSSAI information supported by the AMF.

[0118] The SMF 900 may select an NG-MCE corresponding to the area to be served from the discovered NG-MCEs, and may send an Nmce_Communication_M3MessageTransfer request message (operation S960). The at least one NG-MCE 920 that has received the message may send a control message included in the request message to the connected NG-RAN, for example, IP multicast tunnel information for a base station to receive IP multicast for an MBS service business. In addition, information including a message requesting the NG-RAN that has received the control message to join the IP multicast may be sent to the SMF through the NG-MCE through the Nmce_Communication_M3MessageTransfer response.

[0119] at the same time, Fig.10 The structure of the first entity in the wireless communication system according to an embodiment of the present disclosure is illustrated. The first entity may be a BM-CPF as an MBS function.

[0120] refer to Fig.10 , the first entity may include a transceiver 1010, a memory 1020, and a processor 1030. According to the control method of the first entity described above, the transceiver 1010 and the processor 1030 of the first entity may operate. However, the elements of the first entity are not limited to the above examples. For example, the first entity may include more or less elements than the above elements. In addition, the transceiver 1010, the memory 1020, and the processor 1030 may be implemented in the form of a single chip.

[0121] The transceiver 1010 may send signals to other entities or receive signals from other entities. Here, the signal may include control information and data. To this end, the transceiver 1010 may include an RF transmitter configured to up-convert and amplify the frequency of the transmitted signal, and an RF receiver configured to perform low noise amplification on the received signal and down-convert the frequency. However, this is only an embodiment of the transceiver 1010, and the elements of the transceiver 1010 are not limited to the RF transmitter and the RF receiver.

[0122] The memory 1020 may store programs and data required for the operation of the first entity. In addition, the memory 1020 may store control information or data included in a signal sent from or received by the first entity. The memory 1020 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, there may be a plurality of memories 1020.

[0123] In addition, the processor 1030 may be configured to control a series of processes to allow the first entity to operate according to the above-described embodiments. There may be a plurality of processors 1030 , and the processor 1030 may perform operations of controlling elements of the first entity by executing a program stored in the memory 1020 .

[0124] For example, the processor 1030 may be configured to control the transceiver 1010 to receive information about a data traffic of a multicast / broadcast service (MBS) session and receive Internet Protocol (IP) address information of the second entity.

[0125] Furthermore, the processor 1030 may generate context information for managing the MBS session, and may establish a control session for the second entity based on the IP address information of the second entity and the context information.

[0126] In addition, the processor 1030 may be configured to determine a transmission method of the MBS data service. Here, the transmission method may be one of broadcast, multicast or unicast transmission methods.

[0127] When the transmission method is determined to be the broadcast or multicast transmission method, the processor 1030 may be configured to perform control, on at least one base station corresponding to a region to which the MBS data service is transmitted, to generate a transmission tunnel with the second entity.

[0128] If the first entity is determined by the third entity as an entity corresponding to the MBS service requested by the Application Function (AF) entity, the processor 1030 may be configured to perform control to receive a request to generate the MBS service.

[0129] Furthermore, the processor 1030 may be configured to control the transceiver 1010 to transmit a response message based on the received MBS service generation request, the response message including information on the second entity and information on a transmission method of the MBS data service.

[0130] Furthermore, the processor 1030 may be configured to send information about the MBS service to the third entity in order to discover the second entity, and when the second entity is discovered by the third entity, the processor may be configured to control the transceiver 1010 to send an MBS session generation request to the second entity. Fig.11 The structure of the second entity in the wireless communication system according to an embodiment of the present disclosure is illustrated. The second entity may be a BM-UPF, which serves as a media anchor.

[0131] refer to Fig.11 , the second entity may include a transceiver 1110, a memory 1120, and a processor 1130. According to the above-mentioned control method of the second entity, the transceiver 1110 and the processor 1130 of the second entity may operate. However, the elements of the second entity are not limited to the above-mentioned examples. For example, the second entity may include more or less elements than the above-mentioned elements. In addition, the transceiver 1110, the memory 1120, and the processor 1130 may be implemented in the form of a single chip.

[0132] The transceiver 1110 may send signals to other entities or receive signals from other entities. Here, the signal may include control information and data. To this end, the transceiver 1110 may include an RF transmitter configured to up-convert and amplify the frequency of the converted signal, and an RF receiver configured to perform low noise amplification on the received signal and down-convert the frequency. However, this is only an embodiment of the transceiver 1110, and the elements of the transceiver 1110 are not limited to the RF transmitter and the RF receiver.

[0133] The memory 1120 may store programs and data required for the operation of the second entity. In addition, the memory 1120 may store control information or data included in a signal sent from or received by the second entity. The memory 1120 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, a plurality of memories 1120 may exist.

[0134] The processor 1130 may be configured to control a series of processes to allow the second entity to operate according to the above-described embodiments. There may be a plurality of processors 1130 , and the processor 1130 may perform operations of controlling elements of the second entity by executing a program stored in the memory 1120 .

[0135] The methods according to the embodiments described in the claims or the present specification may be implemented by hardware, software or a combination of hardware and software.

[0136] When these methods are implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors in an electronic device. At least one program may include instructions for causing an electronic device to perform the methods of the various embodiments of the present disclosure disclosed in the accompanying claims and / or this document.

[0137] Programs (software modules or software) can be stored in non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage devices, compact disk ROM (CD-ROM), digital versatile disk (DVD), or other types of optical storage devices, or magnetic tapes. Optionally, any combination of some or all of them can form a memory for storing programs. In addition, multiple such memories may be included in the electronic device.

[0138] In addition, the program can be stored in a connectable storage device that can access the electronic device through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), and a storage area network (SAN) or a combination thereof. Such a storage device can access the electronic device through an external port. In addition, a separate storage device on a communication network can access the portable electronic device.

[0139] In the above detailed embodiments of the present disclosure, the elements included in the present disclosure are expressed in the singular or plural, depending on the detailed embodiments proposed. However, for ease of description, the singular form or the plural form is appropriately selected, and the present invention is not limited to the elements expressed in the singular or plural. Therefore, an element expressed in the plural may also include a single element, or an element expressed in the singular may also include a plurality of elements.

[0140] Although specific embodiments are described in the detailed description of the present disclosure, various modifications and changes may be made thereto without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be defined as being limited to the embodiments, but should be defined by the appended claims and their equivalents.

Claims

1. A method performed by a session management function (SMF) entity, the method include: Based on a multicast / broadcast service (MBS) service area, sending a first request message to a network repository function (NRF) entity to discover at least one access and mobility management function (AMF) entity supporting MBS; receiving, from the NRF entity, a response message including information about at least one discovered AMF entity supporting MBS; as well as Based on the response message received from the NRF entity, at least one AMF is selected from at least one discovered AMF entity supporting MBS.

2. The method according to claim 1, in, The first request message includes a Tracking Area Identity (TAI) list.

3. The method according to claim 1, in, The at least one AMF is selected based on the MBS service area.

4. The method according to claim 1, further comprising: include: A second request message for transmitting control information to at least one Next Generation (NG) Radio Access Network (RAN) is sent to the selected at least one AMF.

5. The method according to claim 4, in, The at least one NG-RAN supports MBS in the MBS service area.

6. The method according to claim 4, further comprising: include: In case the NG-RAN joins the multicast group, a setup response message is received from the NG-RAN among the at least one NG-RAN via the selected at least one AMF.

7. The method according to claim 1, in, The SMF entity is a multicast / broadcast (MB)-SMF entity, and the MB-SMF is co-located with a normal SMF entity.

8. A session management function (SMF) entity, the SMF entity include: Transceiver; as well as At least one processor configured to: Based on a multicast / broadcast service (MBS) service area, sending a first request message to a network repository function (NRF) entity via a transceiver to discover at least one access and mobility management function (AMF) entity supporting the MBS, receiving, via the transceiver, from the NRF entity a response message including information about at least one discovered AMF entity supporting MBS, and Select at least one AMF from at least one discovered AMF entity supporting MBS based on the response message received from the NRF entity.

9. The SMF entity according to claim 8, in, The first request message includes a Tracking Area Identity (TAI) list.

10. The SMF entity according to claim 8, in, The at least one AMF is selected based on the MBS service area.

11. The SMF entity according to claim 8, in, The at least one processor is further configured to send, via the transceiver, to the selected at least one AMF a second request message for transmitting control information to at least one Next Generation (NG) Radio Access Network (RAN).

12. The SMF entity according to claim 11, in, The at least one NG-RAN supports MBS in the MBS service area.

13. The SMF entity according to claim 11, in, The at least one processor is further configured to receive, via the transceiver, a setup response message from an NG-RAN among the at least one NG-RAN via the selected at least one AMF, in a case where the NG-RAN joins the multicast group.

14. The SMF entity according to claim 8, in, The SMF entity is a multicast / broadcast (MB)-SMF entity, and the MB-SMF is co-located with a normal SMF entity.

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