Network element discovery method and apparatus, electronic device, and storage medium

Abstract

The application provides a network element discovery method and device, electronic equipment and storage medium, relates to the technical field of communication, and solves the problem that the data transmission distance is too long in the home network and the roaming network when the terminal device roams in the 5G core network. The method comprises the following steps: a core network device receives a PDU session establishment request from a terminal device; wherein the PDU session establishment request comprises location information of the terminal device; the core network device is a core network device in a roaming network of the terminal device; the core network device determines a home SMF and a roaming SMF according to the location information; the roaming SMF is used for obtaining service data of the terminal device and forwarding the service data of the terminal device to the home SMF; and the home SMF is used for receiving the service data of the terminal device from the roaming SMF and processing the service data of the terminal device. The application is used in the 5G core network roaming process of the terminal device.

Description

Technical Field

[0001] This application relates to the field of information processing technology, and in particular to a method, apparatus, electronic device and storage medium for network element discovery. Background Technology

[0002] The current 3rd Generation Partnership Project (3GPP) and other international standards organizations define the architecture, protocols, and signaling procedures for standard international roaming. In standard international roaming scenarios, the home operator's gateway offices (including network elements such as Security Edge Protection Proxies (SEPP) connections, Home Service Management Function (hSMF), and Home User Plane Function (UPF)) are centrally located in one place. When a user roams to an overseas operator, the roaming user's data needs to be transmitted from the overseas operator to the home operator through the gateway office.

[0003] In 5G inter-network roaming scenarios, if the 5G core network is networked according to standard international home routing, and the home operator's gateway offices are all centrally located, the following problems will arise: First, the number of users and traffic volume in 5G inter-network roaming are far greater than in international roaming, making it difficult for a centralized gateway office to handle the large number of users and traffic. Second, centralized gateway offices lead to excessively long transmission distances between the hSMF and hUPF within the gateway office and the home operator's vSMF and vUPF, resulting in high transmission latency, impacting user experience, and increasing network construction investment in the transmission network. Summary of the Invention

[0004] This application provides a network element discovery method, apparatus, electronic device, and storage medium, which solves the problem in the prior art that the data transmission distance between the home network and the roaming network is too long when the terminal device is roaming in the 5G core network.

[0005] In a first aspect, a network element discovery method is provided, comprising: a core network device receiving a PDU session establishment request from a terminal device; wherein the PDU session establishment request includes location information of the terminal device; the core network device is a core network device in the roaming network of the terminal device; the core network device determines the home SMF and the roaming SMF based on the location information; wherein the roaming SMF is the SMF in the roaming network and the home SMF is the SMF in the home network; the roaming SMF is used to acquire service data of the terminal device and forward the service data of the terminal device to the home SMF; the home SMF is used to receive service data of the terminal device from the roaming SMF and process the service data of the terminal device.

[0006] In conjunction with the first aspect above, in one possible implementation, the core network device determines the roaming SMF and the roaming SMF based on location information, including: the core network device generating a network element discovery request message based on a PDU session establishment request; the network element discovery request message including the location information of the terminal device; the core network device sending the network element discovery request message to the roaming NRF; the roaming NRF being an NRF in the roaming network; the core network device receiving a network element discovery response message from the roaming NRF; the network element discovery response message indicating at least one of the home SMF and the roaming SMF.

[0007] In conjunction with the first aspect above, in one possible implementation, the network element discovery response message is used to indicate the roaming SMF; the roaming SMF is the SMF in the roaming network determined by the roaming NRF whose location with the terminal device meets the first preset condition; the network element discovery response message is the network element discovery response message generated by the roaming NRF based on the roaming SMF.

[0008] In conjunction with the first aspect above, in one possible implementation, the network element discovery response message is used to indicate the home SMF; the home SMF is the SMF in the home network determined by the home NRF after the roaming NRF forwards the network element discovery request message to the home NRF, which satisfies the second preset condition with respect to the location information of the terminal device; the network element discovery response message is the network element discovery response message generated by the home NRF based on the home SMF.

[0009] In conjunction with the first aspect above, in one possible implementation, before the core network device sends a network element discovery request message to the roaming NRF, the method further includes: the core network device determining the roaming NRF based on the NRF address information configured in the core network device.

[0010] In conjunction with the first aspect above, in one possible implementation, before the core network device sends a network element discovery request message to the roaming NRF, the method further includes: the core network device generating a first slice selection request message; the first slice request message including Single Network Slice Selection Auxiliary Information (S-NSSAI) mapped by the terminal device in the roaming network; the core network device sending the first slice selection request message to the roaming NSSF; the roaming NSSF being an NSSF in the roaming network; the core network device receiving a first slice selection response message from the roaming NSSF; the first slice selection response message indicating the NRF corresponding to the S-NSSAI in the roaming network; and the core network device determining that the NRF indicated by the first slice selection response message is the roaming NRF.

[0011] In conjunction with the first aspect above, in one possible implementation, before the core network device sends a network element discovery request message to the roaming NRF, the method further includes: the core network device determining the home network information of the terminal device; and the core network device determining the home NRF based on the home network information of the terminal device.

[0012] In conjunction with the first aspect mentioned above, in one possible implementation, the home NRF is the NRF in the home network determined by the roaming NRF based on the home network information of the terminal device; the roaming NRF is determined by the core network device based on the NRF address information configured in the core network device.

[0013] In conjunction with the first aspect above, in one possible implementation, before the core network device sends a network element discovery request message to the roaming NRF, the method further includes: the core network device generating a second slice selection request message; the second slice request message includes Single Network Slice Selection Auxiliary Information (S-NSSAI) mapped by the terminal device in the roaming network, and a first identifier; the first identifier is used to characterize that the second slice request message is used to establish a PDU session for the terminal device in the home network; the core network device sends the second slice selection request message to the roaming NSSF; the core network device receives a second slice selection response message from the roaming NSSF, the second slice selection response message is used to indicate the NRF in the home network corresponding to S-NSSAI; the core network device determines that the NRF indicated by the second slice selection response message is the home NRF.

[0014] In conjunction with the first aspect above, in one possible implementation, the home NRF is the NRF determined by the home NSSF in the home network based on S-NSSAI after the roaming NSSF forwards the second slice selection request message to the home NSSF; the home NSSF is the NSSF in the home network; and the second slice selection response message is the slice selection response message generated by the home NSSF based on the home NRF.

[0015] In conjunction with the first aspect mentioned above, in one possible implementation, the home NSSF is the roaming NSSF determined by the PLMN identifier of the terminal device's home network.

[0016] In conjunction with the first aspect above, in one possible implementation, when the NRF in the home network is a hierarchically configured NRF, the home SMF is the SMF in the home network that meets the first preset condition determined by the home NRF based on the location information after the home NRF forwards the network element discovery request message to the secondary NRF; the secondary NRF is the next level NRF after the home NRF; the network element discovery response message is the network element discovery request message generated by the secondary NRF based on the home SMF.

[0017] In conjunction with the first aspect above, in one possible implementation, the location information of the terminal device includes at least one of the following: the tracking area identifier (TAI) of the terminal device; the service area of ​​the roaming network element corresponding to the terminal device; the roaming network element includes at least one of roaming AMF and roaming SMF.

[0018] Secondly, a network element discovery device is provided, comprising: a communication unit and a processing unit; the communication unit is configured to receive a PDU session establishment request from a terminal device; wherein the PDU session establishment request includes location information of the terminal device; the network element discovery device is a core network device in the roaming network of the terminal device; the processing unit is configured to determine the home SMF and the roaming SMF based on the location information; wherein the roaming SMF is an SMF in the roaming network, and the home SMF is an SMF in the home network; the roaming SMF is configured to acquire service data of the terminal device and forward the service data of the terminal device to the home SMF; the home SMF is configured to receive service data of the terminal device from the roaming SMF and process the service data of the terminal device.

[0019] In conjunction with the second aspect above, in one possible implementation, the processing unit is specifically configured to: generate a network element discovery request message based on a PDU session establishment request; the network element discovery request message includes the location information of the terminal device; instruct the communication unit to send the network element discovery request message to the roaming NRF; the roaming NRF is an NRF in the roaming network; instruct the communication unit to receive a network element discovery response message from the roaming NRF; the network element discovery response message is used to indicate at least one of the home SMF and the roaming SMF.

[0020] In conjunction with the second aspect above, in one possible implementation, the network element discovery response message is used to indicate the roaming SMF; the roaming SMF is the SMF in the roaming network determined by the roaming NRF that satisfies the first preset condition with respect to the location of the terminal device; the network element discovery response message is the network element discovery response message generated by the roaming NRF based on the roaming SMF.

[0021] In conjunction with the second aspect above, in one possible implementation, the network element discovery response message is used to indicate the home SMF; the home SMF is the SMF in the home network determined by the home NRF after the roaming NRF forwards the network element discovery request message to the home NRF, which satisfies the second preset condition with respect to the location information of the terminal device; the network element discovery response message is the network element discovery response message generated by the home NRF based on the home SMF.

[0022] In conjunction with the second aspect above, in one possible implementation, the processing unit is further configured to: determine the roaming NRF based on the NRF address information configured in the network element discovery device.

[0023] In conjunction with the second aspect above, in one possible implementation, the processing unit is further configured to: generate a first slice selection request message; the first slice selection request message includes Single Network Slice Selection Assist Information (S-NSSAI) mapped by the terminal device in the roaming network; instruct the communication unit to send the first slice selection request message to the roaming NSSF; the roaming NSSF is an NSSF in the roaming network; instruct the communication unit to receive a first slice selection response message from the roaming NSSF; the first slice selection response message is used to indicate the NRF corresponding to S-NSSAI in the roaming network; and determine that the NRF indicated by the first slice selection response message is a roaming NRF.

[0024] In conjunction with the second aspect above, in one possible implementation, the processing unit is further configured to: determine the home network information of the terminal device; and determine the home NRF based on the home network information of the terminal device.

[0025] In conjunction with the second aspect above, in one possible implementation, the home NRF is the NRF in the home network determined by the roaming NRF based on the home network information of the terminal device; the roaming NRF is determined by the network element discovery device based on the NRF address information configured in the network element discovery device.

[0026] In conjunction with the second aspect above, in one possible implementation, the processing unit is further configured to: generate a second slice selection request message; the second slice request message includes Single Network Slice Selection Assist Information (S-NSSAI) mapped by the terminal device in the roaming network, and a first identifier; the first identifier is used to characterize that the second slice request message is used to establish a PDU session for the terminal device in the home network; instruct the communication unit to send the second slice selection request message to the roaming NSSF; instruct the communication unit to receive a second slice selection response message from the roaming NSSF, the second slice selection response message being used to indicate the NRF in the home network corresponding to the S-NSSAI; and determine that the NRF indicated by the second slice selection response message is the home NRF.

[0027] In conjunction with the second aspect above, in one possible implementation, the home NRF is the NRF determined by the home NSSF in the home network based on S-NSSAI after the roaming NSSF forwards the second slice selection request message to the home NSSF; the home NSSF is the NSSF in the home network; and the second slice selection response message is the slice selection response message generated by the home NSSF based on the home NRF.

[0028] In conjunction with the second aspect above, in one possible implementation, the home NSSF is the roaming NSSF determined by the PLMN identifier of the terminal device's home network.

[0029] In conjunction with the second aspect above, in one possible implementation, when the NRF in the home network is a hierarchically configured NRF, the home SMF is the SMF in the home network that meets the first preset condition determined by the second-level NRF based on the location information after the home NRF forwards the network element discovery request message to the second-level NRF; the second-level NRF is the next-level NRF of the home NRF; and the network element discovery response message is the network element discovery request message generated by the second-level NRF based on the home SMF.

[0030] In conjunction with the second aspect above, in one possible implementation, the location information of the terminal device includes at least one of the following: the tracking area identifier (TAI) of the terminal device; the service area of ​​the roaming network element corresponding to the terminal device; the roaming network element includes at least one of roaming AMF and roaming SMF.

[0031] Thirdly, this application provides an electronic device comprising: a processor and a communication interface; the communication interface and the processor are coupled, the processor being configured to run computer programs or instructions to implement the network element discovery method as described in the first aspect and any possible implementation thereof.

[0032] Fourthly, this application provides a computer-readable storage medium storing instructions that, when executed by a processor of a network element discovery device, enable the network element discovery device to perform the network element discovery method as described in the first aspect and any possible implementation thereof.

[0033] In this application, the names of the aforementioned network element discovery devices do not limit the devices or functional modules themselves. In actual implementation, these devices or functional modules may appear under other names. As long as the functions of each device or functional module are similar to those of this invention, they fall within the scope of the claims of this invention and their equivalents.

[0034] These or other aspects of the invention will become more apparent from the following description.

[0035] The technical solution provided in this application brings at least the following beneficial effects: In the embodiments of this application, when a terminal device requests to establish a PDU session in a roaming network, the location information of the terminal device is carried in the PDU session establishment request. In this way, the core network equipment of the roaming network can select the nearest roaming SMF and home SMF for the terminal device to transmit the service data generated by the terminal device in the roaming network based on the terminal device's location information, thereby reducing the transmission distance of the service data generated by the terminal device in the roaming network, reducing service latency, and improving user experience. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a network element discovery device provided in an embodiment of this application; Figure 2 A schematic diagram illustrating the mobility of a terminal device during roaming in a 5G core network, provided as an embodiment of this application; Figure 3 A schematic diagram illustrating the connection between a home network and a roaming network provided in an embodiment of this application; Figure 4 A point-to-point architecture diagram of a 5G core network roaming network is provided in this application embodiment; Figure 5 This is a schematic diagram of an SMF (Separate Area Configuration) setting provided in an embodiment of this application; Figure 6 A flowchart illustrating a network element discovery method provided in an embodiment of this application; Figure 7 A flowchart illustrating another network element discovery method provided in this application embodiment; Figure 8 A flowchart illustrating another network element discovery method provided in this application embodiment; Figure 9 A flowchart illustrating another network element discovery method provided in this application embodiment; Figure 10 This is a schematic diagram of a network element discovery device provided in an embodiment of this application. Detailed Implementation

[0037] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0038] The terms "first" and "second," etc., used in the specification and drawings of this application are used to distinguish different objects or to distinguish different treatments of the same object, rather than to describe a specific order of objects.

[0039] Furthermore, the terms "comprising" and "having," and any variations thereof, used in the description of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0040] It should be noted that in the embodiments of this application, the words "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the words "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0041] In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0042] To implement the network element discovery method provided in this application embodiment, this application embodiment provides a network element discovery apparatus for executing the network element discovery method. Figure 1 This is a schematic diagram of a network element discovery device provided in an embodiment of this application. Figure 1 As shown, the network element discovery device 100 includes at least one processor 101, a communication line 102, and at least one communication interface 104, and may also include a memory 103. The processor 101, memory 103, and communication interface 104 can be connected via the communication line 102.

[0043] The processor 101 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application, such as one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs).

[0044] Communication line 102 may include a path for transmitting information between the aforementioned components.

[0045] The communication interface 104 is used to communicate with other devices or communication networks. It can use any transceiver-like device, such as Ethernet, radio access network (RAN), wireless local area network (WLAN), etc.

[0046] The memory 103 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of including or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto.

[0047] In one possible design, the memory 103 can exist independently of the processor 101, meaning the memory 103 can be an external memory of the processor 101. In this case, the memory 103 can be connected to the processor 101 via the communication line 102 to store execution instructions or application code, and its execution is controlled by the processor 101 to implement the network element discovery method provided in the following embodiments of this application. In another possible design, the memory 103 can also be integrated with the processor 101, meaning the memory 103 can be an internal memory of the processor 101. For example, the memory 103 can be a cache, which can be used to temporarily store some data and instruction information.

[0048] As one possible implementation, processor 101 may include one or more CPUs, for example Figure 1 CPU0 and CPU1 in the example. Alternatively, the network element discovery device 100 may include multiple processors, such as CPU0 and CPU1. Figure 1 The processors 101 and 107 are included. Alternatively, the network element discovery device 100 may also include an output device 105 and an input device 106.

[0049] The following explanations of the terms used in the embodiments of this application are provided to facilitate the reader's understanding.

[0050] 1. 5G inter-network roaming 5G inter-network roaming refers to a roaming method in which a terminal device belonging to operator A accesses the 5G network of operator B, and operator B provides 5G network services for the terminal device.

[0051] 5G inter-network roaming is typically used in scenarios where an area is covered by the 5G network of operator B but not by the 5G network of operator A. Network deployment based on 5G inter-network roaming can accelerate 5G infrastructure construction, reduce redundant 5G network construction, and achieve 5G network coverage and business development in a compact and efficient manner.

[0052] Currently, 5G inter-network roaming includes two methods: 5G core network roaming and 5G access network roaming. This application mainly concerns 5G core network roaming, and the implementation methods of 5G core network roaming are described in detail below.

[0053] 2. 5G core network roaming 5G core network roaming refers to a situation where, within a certain network coverage area, if one operator (e.g., operator B) has constructed a 5G network (including the access network and core network) within that area, then terminal devices belonging to other operators (operator A) can also access the 5G network built by operator B through roaming. Operator B's 5G network then provides 5G network services to the terminal devices belonging to operator A. In this case, for the terminal device, operator B is designated as the roaming operator, operator A as the home operator, and the network coverage area is designated as the roaming area.

[0054] In 5G core network roaming scenarios, the home network includes the home operator's 5G core network, the home operator's 4G core network, the home operator's Internet Protocol (IP) Multimedia Subsystem (IMS) network, the home operator's 5G access network, and the home operator's 4G access network.

[0055] The roaming network includes the roaming operator's 5G core network and the roaming operator's 5G access network.

[0056] In 5G core network roaming scenarios, when a terminal device moves from its home network to the roaming network, the data generated by the terminal device in the roaming network is returned to the home network via home routing, where the home network processes the service data generated by the terminal device. The signaling planes of the home network's core network (including the home operator's 5G core network (5GC) and 4G core network's evolved packet core (EPC)) and the roaming network's core network (including the roaming operator's 5GC) are connected through security edge protection proxies (SEEP). The user plane is connected via edge routers through the user plane function (UPF) between the home network and the visited network.

[0057] In 5G core network roaming, based on whether the home operator has a wireless signal in the roaming area, 5G core network roaming is divided into the following two scenarios.

[0058] Scenario 1: The home operator has no wireless network signal in the roaming area, while the roaming operator has 4G or 5G signals in the roaming area, and the terminal device only uses the 5G network of the roaming network.

[0059] Specifically, Scene 1 includes both an outward-floating scene and a backward-floating scene. These will be explained separately below: Roaming Out Scenario: When a terminal device enters a roaming area, it will prioritize using the roaming operator's 5G network to provide 5G roaming services; the roaming operator will not provide 4G roaming services. In this scenario, the roaming operator does not support the terminal device's voice services falling back to the roaming operator's 4G network.

[0060] Roaming back scenario: The user's terminal device leaves the roaming area and finds its home operator's network signal (which can be a 4G or 5G network signal). The terminal device rejoins the home operator's network, and the home operator provides network services to the terminal device. In this scenario, the terminal device can perform voice service fallback normally.

[0061] In Scenario 1, the roaming scenario means that since the home operator's network has no signal in the roaming area, the home operator's terminal devices will, by default, only operate on the roaming network's 5G network after roaming to the shared area. In this scenario, the roaming operator will not need to support service continuity for the terminal devices.

[0062] However, in the roaming scenario of Scenario 1, when a terminal device moves from its home operator network (hereinafter referred to as the home network) to the roaming operator network (hereinafter referred to as the roaming network), after disconnecting from the home network, the terminal device needs a relatively long time to reconnect to the roaming network. This may result in a prolonged interruption of the user's ongoing services and a poor user experience.

[0063] Scenario 2: The home operator has 4G network signal but no 5G network signal in the roaming area, while the roaming operator has either 4G or 5G network in the roaming area. The terminal device prioritizes using the roaming operator's 5G network in the roaming area. When the roaming operator's 5G network coverage is insufficient, it uses the home operator's 4G network.

[0064] Scene 2 also includes out-of-scene and out-of-scene scenarios, which will be explained below.

[0065] Roaming Scenario: When a user's terminal device enters a roaming area, the terminal device will prioritize using the roaming operator's 5G network to provide 5G roaming services. When the roaming operator's 5G network coverage is insufficient, the terminal device will use its home operator's 4G network.

[0066] Roaming back scenario: The user's terminal device leaves the roaming area and searches for a signal on its home operator's network (which can be a 4G or 5G network). The terminal device returns to its home operator's network, and the home operator provides network services to the terminal device.

[0067] Currently, there is no discussion on methods for ensuring service continuity in Scenario 2, and there are no service standards or equipment to support service continuity in Scenario 2. Therefore, how to improve service continuity in 5G inter-network roaming scenarios has become an urgent technical problem to be solved.

[0068] In this embodiment, it is mainly used to solve the voice service continuity problem in scenario 2 of the above-mentioned 5G core network roaming.

[0069] like Figure 2 The diagram illustrates the mobility of a terminal device during 5G core network roaming, as provided in an embodiment of this application. Scenario 2 includes region 1 and region 2, where the home operator's 5G network covers region 1, and the roaming operator's 5G network covers region 2 (region 2 is also referred to as the roaming area). The home operator's 4G network covers both region 1 and region 2.

[0070] When the terminal device is in such Figure 2 When moving between the shown areas 1 and 2, the movement of the terminal device includes at least the following cases 1-4.

[0071] Scenario 1: The terminal device moves from the home operator's 4G network to the roaming operator's 5G network.

[0072] Scenario 2: The terminal device moves from the roaming operator's 5G network to the home operator's 4G network.

[0073] Scenario 3: The terminal device moves from the home operator's 5G network to the roaming operator's 5G network.

[0074] Scenario 4: The terminal device is moved from the roaming operator's 5G network to the home operator's 5G network.

[0075] Figure 3 This is a schematic diagram illustrating the connection between a home network and a roaming network, provided as an embodiment of this application.

[0076] like Figure 3 As shown, the data plane between the home network's 5G network and the roaming network's (also known as the visited network's 5G network) is connected via hSEPP and vSEPP; the user plane between the home network and the roaming network is connected via UPF. hSEPP and vSEPP are connected via the N32 interface, and UPFs are connected via the N9 interface.

[0077] When a terminal device moves from its home network to a roaming network, the data generated by the terminal device in the roaming network is returned to the home network using the home routing method, and the home network processes the service data generated by the terminal device.

[0078] The N32 interface between hSEPP and vSEPP aggregates and isolates the N8, N12, N16, N24, N27, and N31 interfaces between the home network and the roaming network. The interface types and access locations of these interfaces are shown in Table 1 below. Table 1

[0079] It should be noted that in this application, the prefix "v" before a network element indicates that the network element is a visited network element, that is, a network element in a roaming network. Adding the prefix "v" before a network element has the same meaning as adding the qualifier "roaming" before the network element.

[0080] The prefix "h" before a network element indicates that the element belongs to its home network. Adding the prefix "h" before a network element has the same meaning as adding the qualifier "home" before the element.

[0081] Currently, international and industry standards define the standard architecture protocols and signaling procedures for international roaming. In international roaming scenarios, when using home-roamed networking, the home operator's gateway offices (including SEPP, hSMF, hUPF, etc.) are centrally configured. When an operator's terminal equipment roams to another operator's network, the terminal equipment's data and voice services are transmitted through these centrally configured gateway offices to the home operator's network, where the home operator processes the terminal equipment's services.

[0082] In international roaming, the number of terminal devices roaming to other operators is relatively small, so the above-mentioned network topology does not generate much service load. However, in 5G core network roaming scenarios, a large number of users may roam to other operators for 5G services. In this case, both the number of terminal devices and the data volume of roaming services are very large. If the existing network topology is still used to centrally set up gateway offices, the data transmission path from the roaming network to the home network's gateway office will result in increased data transmission latency and significantly increased construction costs for the transmission network from the roaming network to the home network's gateway office.

[0083] One example, Figure 4 This application provides a point-to-point architecture for 5G core network roaming (home routing mode) architecture.

[0084] like Figure 4 As shown, in this application, the home network and the roaming network are connected via the N32 interface between the home SEPP and the roaming SEPP; the home NSSF and the roaming NSSF are connected via the N31 interface; the home NRF and the roaming NRF are connected via the N27 interface; the home HSS+UDM and the roaming Authentication Management Function (AMF) are connected via the N8 and / or N12 interfaces; the home PCF and / or the home PCRF and the roaming PCF are connected via the N24 interface; the home SMF and / or the home PGW-C and the roaming SMF and / or the roaming PGW-C are connected via the N16 interface; and the home UPF and / or the home PGW-U and the roaming UPF and / or the roaming PGW-U are connected via the N9 interface.

[0085] In the home network, the terminal device connects to the home AMF via the N1 interface; the NR connects to the AMF via the N2 interface; the NR connects to the home UPF and / or home PGW-U via the N3 interface; the AMF connects to the home SMF and / or home PGW-C via the N11 interface; the AMF connects to the home HSS+UDM via the N8 and / or N12 interfaces; the home HSS+UDM connects to the home SMF and / or home PGW-C via the N10 interface; the home SMF and / or home PGW-C connect to the home SGW via the S5 interface; the home SGW and eNB are connected via the S1-U interface; and the home SMF and / or home PGW-C connect to the home PCF and / or home PCRF via the N7 interface.

[0086] In a roaming network, the terminal device connects to the roaming AMF via the N1 interface; the NR connects to the AMF via the N2 interface; the NR connects to the roaming UPF and / or the roaming PGW-U via the N3 interface; the AMF connects to the roaming SMF and / or the roaming PGW-C via the N11 interface; and the roaming SMF and / or the roaming PGW-C connects to the roaming UPF and / or the roaming PGW-U via the N4 interface.

[0087] Figure 5 This is a schematic diagram illustrating an SMF (Separate Area Configuration) setting provided in an embodiment of this application. Figure 5 As shown, the home operator sets up home SMFs in multiple areas, and similarly, the roaming operator can also set up home SMFs in multiple areas. Within the same area, the home SMF and roaming SMF are centrally located; communication connections exist between the home SMF and roaming SMF. Thus, after a terminal device roams to the roaming operator's 5G network in a certain area, the terminal device can send its service data to the home SMF in that area through the roaming SMF, which then processes the terminal device's service data.

[0088] As an example, the same area described in this application can be an area divided by administrative regions. For example, the same province can be considered the same area. The home operator and the roaming operator set up SMFs (Search Engine Management Units) in the same province and established communication connections between the SMFs.

[0089] based on Figure 5The configuration scheme of Home SMF and Roaming SMF shown in the diagram allows a terminal device to receive home routing services in a roaming scenario when roaming to an area, provided by both the Home SMF and Roaming SMF within that area. Since the Home SMF and Roaming SMF are located within the same area, the transmission distance between them is short. Therefore, when the terminal device's service data is transmitted across operator networks, it only needs to travel a short distance from the roaming network to the home network, significantly reducing the cross-operator network transmission distance, thereby reducing data transmission latency and lowering the construction cost of the transmission bearer network at the gateway office between the roaming network and the home network.

[0090] Currently, international standards organizations such as 3GPP have defined the architecture, protocols, and signaling procedures for standard international roaming. In standard international roaming scenarios, the gateway offices (including network elements such as SEPP, hSMF, and hUPF) of the home operator are centrally located in the same location. When a user roams to an overseas operator, the roaming user's data needs to be transmitted from the overseas operator to the home operator through the gateway office.

[0091] In 5G inter-network roaming scenarios, if the 5G core network is networked according to standard international home routing, and the home operator's gateway offices are all centrally located, the following problems will arise: First, the number of users and traffic volume in 5G inter-network roaming are far greater than in international roaming, making it difficult for a centrally located gateway office to handle the large number of users and traffic. Second, a centrally located gateway office will result in excessively long transmission distances between the hSMF and hUPF within the gateway office and the home operator's vSMF and vUPF, leading to high transmission latency, impacting user experience, and increasing network construction investment in the transmission network.

[0092] To address the problems existing in the prior art, this application provides a network element discovery method for carrying large volumes of user data in 5G inter-network roaming scenarios and reducing transmission distance.

[0093] like Figure 6 As shown, this is a network element discovery method provided in an embodiment of the present application, which includes the following steps S601-S602.

[0094] S601. The terminal device sends a Protocol Data Unit (PDU) session establishment request to the core network device. Correspondingly, the core network device receives the PDU session establishment request from the terminal device.

[0095] The PDU session establishment request includes the location information of the terminal device; the core network device is the core network device in the roaming network of the terminal device. As an example, the core network device described in this application is the roaming AMF in the roaming network.

[0096] In one possible implementation, when the terminal device moves to an area covered by the 5G network of the roaming network, the terminal device sends a PDU session establishment request to the core network equipment. In this way, the terminal device can conduct 5G network services through the 5G network of the roaming network.

[0097] Optionally, the PDU session establishment request may also include at least one of the following: Single Network Slice Selection Assistance Information (S-NSSAI), the S-NSSAI mapped by the terminal device in the roaming network, the public land mobile network (PLMN) identifier of the terminal device's SUPI (i.e., the identifier of the PLMN of the terminal device's home network), and the slice instance.

[0098] S602. The core network equipment determines the home SMF and roaming SMF based on the location information.

[0099] Among them, the roaming SMF is the SMF in the roaming network, and the home SMF is the SMF in the home network; the roaming SMF is used to obtain the service data of the terminal device and forward the service data of the terminal device to the home SMF; the home SMF is used to receive the service data of the terminal device from the roaming SMF and process the service data of the terminal device.

[0100] In one possible implementation, after the core network device determines the location information of the terminal device, the SMF in the roaming network determined by the core network device that meets the first preset condition with respect to the location of the terminal device is the roaming SMF.

[0101] The location information of the terminal device in the home network determined by the core network equipment meets the second preset condition of SMF.

[0102] In one example, both the first and second preset conditions are the closest distance to the location of the terminal device.

[0103] The above solution offers at least the following advantages: In this embodiment, when a terminal device requests to establish a PDU session in a roaming network, the location information of the terminal device is carried in the PDU session establishment request. This allows the core network equipment of the roaming network to select the nearest roaming SMF and home SMF for transmitting service data generated by the terminal device in the roaming network based on the terminal device's location information. This reduces the transmission distance of service data generated by the terminal device in the roaming network, lowers service latency, and improves user experience.

[0104] The following section provides a detailed explanation of the specific implementation process of S602, combined with... Figure 6 ,like Figure 7 As shown, the above S602 can be specifically implemented through the following S701-S704.

[0105] S701. The core network equipment generates a network element discovery request message based on the PDU session establishment request.

[0106] The network element discovery request message includes the location information of the terminal device.

[0107] In one possible implementation, in addition to the location information of the terminal device, the network element discovery request message corresponding to the PDU session establishment request also includes at least one of the following information: allowed S-NSSAI, data network name (DNN), the S-NSSAI mapped by the terminal device in the roaming network, the PLMN identifier of the terminal device's SUPI (also known as the PLMN identifier of the terminal device's home network), and the slice instance.

[0108] In one specific implementation, the network element discovery request message is an Nnrf_NFDiscovery_Reques message sent by the roaming AMF to the roaming network storage function (NRF).

[0109] S702. The core network device sends a network element discovery request message to the roaming NRF. Correspondingly, the roaming NRF receives the network element discovery request message from the core network device.

[0110] In one possible implementation, the core network device sends an Nnrf_NFDiscovery_Reques request to the roaming NRF to query the home SMF and the roaming SMF. Correspondingly, after receiving the Nnrf_NFDiscovery_Reques request from the terminal device, the roaming NRF executes the home SMF discovery procedure and the roaming NRF discovery procedure to determine the home SMF and the roaming SMF.

[0111] It should be noted that before the core network device sends a network element discovery request message to the roaming NRF, the core network device can determine the roaming NRF in the following two ways.

[0112] Method 1: If the roaming AMF cannot directly detect the roaming NRF, the core network device sends a slice selection response message to the roaming NSSF. The roaming network slice selection function (NSSF) selects the NRF based on the slice selection response message and returns the selected NRF to the core network device.

[0113] Method 2: If the roaming AMF can directly detect the roaming NRF, then the roaming AMF determines the roaming NRF based on the PLMN identifier of the terminal device's home network or the terminal device's number segment.

[0114] S703, Roaming NRF determines network element discovery response message.

[0115] The network element discovery request response message is used to indicate at least one of the home SMF and the roaming SMF.

[0116] In one possible implementation, the roaming NRF determines at least one of the home SMF and the roaming SMF based on the network element discovery request message, and generates a network element discovery request message based on at least one of the SMF and the roaming SMF.

[0117] Optionally, the method for roaming NRF to discover roaming SMFs can be implemented as follows: when the roaming network supports standard slicing, the roaming NRF selects the roaming SMF that provides 5G core network roaming services to the terminal device based on the location information of the terminal device and the PLMN identifier of the terminal device's home network in the network element discovery request message.

[0118] When the roaming network supports non-standard slicing, the roaming NRF selects the roaming SMF that provides 5G core network roaming services to the terminal device based on the location information of the terminal device in the network element discovery request message, the PLMN identifier of the terminal device's home network, and the S-NSSAI mapped by the terminal device in the roaming network.

[0119] Optionally, the process of the roaming NRF discovering the home SMF can be implemented as follows: the roaming NRF forwards the network element discovery request message to the home NRF.

[0120] When the roaming network supports standard slicing, the roaming NRF selects the roaming SMF that provides 5G core network roaming services to the terminal device based on the location information of the terminal device in the network element discovery request message, the roaming AMF and the roaming SMF's service scope, and the DNN.

[0121] When the roaming network supports non-standard slicing, the roaming NRF selects the roaming SMF that provides 5G core network roaming services to the terminal device based on the terminal device's location information (servingScope), the service area of ​​the roaming AMF (i.e., the roaming SMF), the DNN, and the S-NSSAI mapped by the terminal device in the roaming network.

[0122] It should be noted that when a roaming SMF registers with a roaming NRF, it sends the information supported by the roaming SMF (including the slice information supported by the SMF, the location area information of the SMF, and the network information supported by the SMF) to the roaming NRF. When the roaming NRF selects a roaming SMF for a terminal device, it selects the appropriate roaming SMF based on the terminal device's requirements (e.g., the terminal device's location information, the service scope of the roaming AMF (i.e., the DNN), and the S-NSSAI mapped by the terminal device in the roaming network) and the SMF's registration information.

[0123] S704. The roaming NRF sends a network element discovery response message to the core network equipment. Correspondingly, the core network equipment receives the network element discovery response message from the roaming NRF.

[0124] After receiving the network element discovery response message from the roaming NRF, the core network equipment parses the network element discovery response message, determines the home SMF procedure and roaming NRF indicated by the network element discovery response message, and determines the home SMF procedure and roaming NRF for providing roaming services to the terminal equipment.

[0125] In one specific implementation, the network element discovery request message is an Nnrf_NFDiscovery_Request response message sent by vNRF to vAMF.

[0126] The above scheme brings at least the following beneficial effects: In this application, the roaming AMF sends the terminal device's location information, slice information, PLMN information, etc., to the roaming NRF, enabling the NRF to select a roaming SMF and a home SMF for the terminal device based on this information. Since the SMF registers its own capability information with the NRF during the registration process, the NRF can select a nearby SMF that can provide services to the terminal device based on the above information.

[0127] The above, combined with Figure 7 This paper introduces the process by which a roaming AMF discovers a roaming SMF and its home SMF using NRF. It should be noted that a roaming AMF can discover a roaming SMF and its home SMF using different discovery processes via NRF, which are explained in detail below by scenario: Scene 1: The process of discovering the roaming SMF while roaming AMF.

[0128] like Figure 8 As shown, the method for roaming AMF to discover roaming SMF can be specifically implemented through the following S801-S804.

[0129] S801. The core network device sends a first slice selection request message to the roaming NSSF. Correspondingly, the roaming NSSF receives the first slice selection request message from the core network device.

[0130] The first slice selection request message includes at least one of the following: the allowed S-NSSAI, the S-NSSAI mapped by the terminal device in the roaming network, the PLMN identifier of the terminal device's SUPI, and the location information of the terminal device.

[0131] In one possible implementation, after the roaming AMF receives a PDU session establishment request from the terminal device, the roaming AMF determines whether it can directly detect the roaming NRF. If the roaming AMF cannot directly detect the roaming NRF, it generates a first slice selection request message based on the PDU session establishment request. The roaming AMF then sends the first slice selection request message to the roaming NSSF.

[0132] In one specific implementation, the first slice selection request message is the Nnssf_NSSelection_Get message sent by the roaming AMF to the roaming NSSF.

[0133] S802, the roaming NSSF sends a first slice selection response message to the core network equipment. Correspondingly, the core network equipment receives the first slice selection response message from the roaming NSSF.

[0134] The first slice selection response message is used to indicate the NRF in the roaming network corresponding to S-NSSAI.

[0135] Optionally, the first slice selection response message includes at least one of the following: the network slice selected according to S-NSSAI, the network slice instance, and the NRF corresponding to the network slice. The NRF corresponding to the network slice is the aforementioned roaming NRF.

[0136] In one specific implementation, after receiving the first slice selection response message from the roaming AMF, the roaming NSSF selects a network slice, a slice instance, and the applicable NRF for that network slice based on the S-NSSAI in the first slice selection request message. The roaming NSSF then generates the first slice selection response message based on the network slice, slice instance, and applicable NRF. Finally, the roaming NSSF sends the first slice selection response message to the roaming AMF.

[0137] It should be noted that, in this application, depending on whether the roaming AMF can detect the roaming NRF, the roaming AMF can selectively execute steps S801 and S802.

[0138] For example, if the roaming AMF can directly detect the roaming NRF, the roaming AMF will not execute steps S801 and S802. Instead, the roaming AMF will determine the roaming NRF based on the PLMN identifier of the terminal device's home network or the terminal device's number range. After this, the roaming AMF will execute the following step S803.

[0139] If the roaming AMF cannot directly detect the roaming NRF, the roaming AMF determines the roaming NRF by executing steps S801 and S802.

[0140] S803. The core network device sends a network element discovery request message to the roaming NRF. Correspondingly, the roaming NRF receives the network element discovery request message from the core network device.

[0141] In one possible implementation, the core network device sends an Nnrf_NFDiscovery_Reques request to the roaming NRF to query the roaming SMF. Correspondingly, after receiving the Nnrf_NFDiscovery_Reques request from the terminal device, the roaming NRF executes the roaming NRF discovery process to find the roaming SMF.

[0142] The core network equipment can determine the roaming NRF in accordance with methods 1 and 2 in S702 above, and this application does not limit it.

[0143] S804. The roaming NRF sends a network element discovery response message to the core network equipment. Correspondingly, the core network equipment receives the network element discovery response message from the roaming NRF. Among them, the network element discovery response message is used to indicate the roaming SMF; the roaming SMF is the SMF in the roaming network whose location with the terminal device meets the first preset condition as determined by the roaming NRF; the network element discovery response message is the network element discovery response message generated by the roaming NRF based on the roaming SMF.

[0144] Specifically, the roaming NRF determines the roaming SMF based on the network element discovery response message and generates a network element discovery response message based on the determined roaming SMF. After this, the roaming NRF sends a network element discovery response message to the roaming AMF. The roaming AMF then determines the roaming SMF based on the network element discovery response message.

[0145] It should be noted that the process by which the roaming NRF determines the roaming SMF based on the network element discovery response message can refer to the process of the roaming NRF discovering the roaming SMF in S703 above, and will not be repeated here.

[0146] The above describes a process for a roaming AMF to discover a roaming SMF. Based on this process, a roaming AMF can discover a roaming SMF through a roaming NRF, thereby identifying the roaming SMF that provides services to the terminal device.

[0147] Scene 2: The process of roaming the AMF and discovering the SMF to which the user belongs.

[0148] like Figure 9 As shown, the method for roaming AMF to discover the belonging SMF can be specifically implemented through the following S901-S908.

[0149] S901, the roaming AMF sends a second slice selection request message to the roaming NSSF. Correspondingly, the roaming NSSF receives the second slice selection request message from the roaming AMF.

[0150] The second slice request message includes at least one of the following: Single Network Slice Selection Auxiliary Information (S-NSSAI) mapped by the terminal device in the roaming network, the PLMN identifier of the terminal device's home network, and a first identifier, which is used to characterize the second slice request message for establishing a PDU session for the terminal device in the home network.

[0151] In one possible implementation, after the roaming AMF receives a PDU session establishment request from the terminal device, the roaming AMF determines whether it can directly detect the roaming NRF. If the roaming AMF cannot directly detect the roaming NRF, it generates a first slice selection request message based on the PDU session establishment request. The roaming AMF then sends the first slice selection request message to the roaming NSSF.

[0152] In one specific implementation, the second slice selection request message is the Nnssf_NSSelection_Get message.

[0153] S902, the roaming NSSF sends a second slice selection request message to the home NSSF. Correspondingly, the home NSSF receives the second slice selection request message from the roaming NSSF.

[0154] In one possible implementation, after receiving the second slice selection request message, the roaming NSSF determines, based on the first representation, that the second slice selection request message is a slice selection request message that needs to be forwarded to the NSSF in the home network. At this time, the roaming NSSF determines the home NSSF based on the PLMN identifier of the terminal device's home network in the second slice selection request message. After this, the roaming NSSF sends the second slice selection request message to the home NSSF.

[0155] S903, the home NSSF sends a second slice selection response message to the roaming NSSF.

[0156] The second slice selection response message is used to indicate the NRF in the home network corresponding to S-NSSAI.

[0157] Optionally, the second slice selection response message may include at least one of the following: the identifier of the home NRF, and the identifier of the slice instance of the home network.

[0158] In one specific implementation, after the home NSSF receives the second slice selection response message from the roaming NSSF, it selects the home NRF based on the S-NSSAI in the second slice selection request message. The home NSSF then generates a first slice selection response message based on the home NRF. Finally, the home NSSF sends the second slice selection response message to the roaming NSSF.

[0159] In one specific implementation, the second slice selection response message is the Nnssf_NSSelection_Getresponse message.

[0160] S904, the roaming NSSF sends a second slice selection response message to the roaming AMF.

[0161] It is understandable that the above S901-S904 are used to determine the home NRF when roaming AMF.

[0162] If the roaming network cannot directly perceive the NRF in the home network, the roaming AMF can determine the home NRF through the above S901-S904.

[0163] If the roaming AMF can directly detect the NRF in the home network, the roaming AMF can determine the roaming NRF based on the PLMN identifier of the terminal device's home network or the terminal device's number range. The roaming NRF, in turn, determines the home NRF based on the PLMN identifier of the terminal device's home network or the terminal device's number range. In this case, there is no need to execute S901-S904 above.

[0164] S905, the roaming AMF sends a network element discovery request message to the roaming NRF.

[0165] The specific implementation process of S905 can be referred to S702 or S803 above, and will not be repeated here. Understandably, the process of roaming AMF discovering roaming NRF can be referenced. Figure 8 The process of discovering the NRF during roaming AMF is understood and will not be elaborated here.

[0166] S906. The roaming NRF sends a network element discovery request message to the home NRF.

[0167] In one possible implementation, during the discovery of the home SMF, since the home SMF usually only registers with the NRF of the home network and not with the NRF of the roaming network, the roaming NRF forwards the network element discovery request message to the home NRF, which then determines the home SMF based on the SMF's registration information.

[0168] Specifically, after receiving a network element discovery request message, the roaming NRF determines the home network based on the PLMN identifier of the terminal device's home network in the network element discovery request message, and then discovers the home NRF from the home network. The roaming NRF sends the network element discovery request message to the home NRF through the roaming SEPP and the home SEPP.

[0169] S907, The home NRF sends a network element discovery response message to the roaming NRF.

[0170] Among them, the network element discovery response message is used to indicate the home SMF; the home SMF is the SMF in the home network determined by the home NRF after the roaming NRF forwards the network element discovery request message to the home NRF, which satisfies the second preset condition with the location information of the terminal device; the network element discovery response message is the network element discovery response message generated by the home NRF based on the home SMF.

[0171] In one possible implementation, the Home NRF determines the Home SMF based on the Network Element Discovery Request message and generates a Network Element Discovery Response message based on the determined Home SMF. Afterward, the Home NRF sends a Network Element Discovery Response message to the Roaming NRF via the Home Roaming SEPP and the Roaming SEPP.

[0172] It should be noted that when the home SMF registers with the home NRF, it sends information supported by the home SMF (including the slice information supported by the SMF, the location area information of the SMF, and the network information supported by the SMF) to the home NRF. When the home NRF selects a home SMF for a terminal device, it selects the appropriate home SMF based on the terminal device's requirements (e.g., the terminal device's location information, the service scope of the home AMF, the DNN, and the S-NSSAI mapped by the terminal device in the home network) and the SMF's registration information.

[0173] S908, the roaming NRF sends a network element discovery response message to the roaming AMF.

[0174] In one possible implementation, after the roaming AMF receives the network element discovery response message from the roaming NRF, it determines the home SMF based on the network element discovery response message.

[0175] The above describes a process for a roaming AMF to discover its home SMF. Based on this process, the roaming AMF can discover its home SMF through the roaming NRF and the home NRF, thereby achieving the goal of discovering the home SMF that provides services to the terminal device.

[0176] It should be pointed out that, Figure 8 and Figure 9 The network element discovery request messages can be the same. In this case, the roaming NRF determines the roaming SMF based on the same network element discovery request message and forwards the network element discovery request message to the home NRF. Alternatively, Figure 8 and Figure 9 The network element discovery request message can also be a different network element discovery request message. In this case, the roaming NRF will execute the corresponding network element discovery request message. Figure 8 and Figure 9 The corresponding process. Similarly, Figure 8 and Figure 9 The network element discovery response message can also be the same network element response message. In this case, the network element response message indicates the roaming SMF and the home SMF respectively. Or, Figure 8 and Figure 9 The network element discovery response message can also be different network element response messages. In this case, one network element response message is used to indicate the roaming SMF, and the other is used to indicate the home SMF. This application does not limit this.

[0177] One possible implementation is, such as Figure 9 As shown, after S906, if the NRF in the home network is a hierarchically configured NRF, the NRF in the home network can determine the network element discovery request message through the following S909 and S910.

[0178] S909, The home NRF sends a network element discovery request message to the secondary NRF.

[0179] In one specific implementation, the home NRF queries the home network for the corresponding secondary NRF (e.g., a local secondary NRF) on behalf of the AMF. After finding the secondary NRF, the home NRF sends a network element discovery request message to the secondary NRF.

[0180] In one example, the home NRF is the overall NRF set by the operator, and the secondary NRF is the NRF set by the operator by province. The home NRF includes information about the NRF of each province.

[0181] S910 and the secondary NRF send a network element discovery response message to the home NRF.

[0182] In one possible implementation, the secondary NRF determines the home SMF based on the network element discovery request message and generates a network element discovery response message based on the home SMF. Afterward, the secondary NRF sends the network element discovery response message to the home NRF.

[0183] It should be noted that in a hierarchical NRF configuration scenario, the home SMF can initiate registration with the secondary NRF. When registering with the secondary NRF, the home SMF sends information supported by the home SMF (including the slice information supported by the SMF, the location area information of the SMF, and the network information supported by the SMF) to the secondary NRF. When the secondary NRF selects a home SMF for the terminal device, it selects the appropriate home SMF based on the terminal device's requirements (e.g., the terminal device's location information, the service scope of the home AMF, the DNN, and the S-NSSAI mapped by the terminal device in the home network) and the SMF's registration information.

[0184] It is understood that a third-level NRF can be set under the aforementioned second-level NRF, and a fourth-level NRF can be set under the third-level NRF, etc. This application does not limit this. When setting up NRFs at multiple levels, the upper-level NRF only needs to forward the network element discovery request message to the lower-level NRF. The NRF that can discover the SMF among the multiple-level NRFs determines the belonging SMF and generates the network element discovery request message. The specific process can be understood by referring to S909 and S910 above, and this application will not elaborate on it.

[0185] The above explains how an NRF determines its home SMF when the NRF in the home network is configured hierarchically.

[0186] It should be noted that in roaming networks, NRFs can also be configured hierarchically. In this scenario, the process of roaming NRFs discovering roaming SMFs can be referred to in S909 and S910 above, and will not be elaborated on here.

[0187] In one possible implementation, the location information of the terminal device in this application includes at least one of the following: the TAI of the terminal device (denoted as Case 1); the service area of ​​the roaming network element corresponding to the terminal device (denoted as Case 2); the roaming network element includes at least one of roaming AMF and roaming SMF.

[0188] The following section, combining the two different scenarios described above, details the process by which NRF selects an SMF for a terminal device based on its location information. Case 1: The location information of the terminal device includes the TAI of the terminal device.

[0189] In scenario 1, the roaming NRF determines the current location (e.g., latitude and longitude) of the terminal device based on its TAI. The roaming NRF then queries the roaming network for SMFs (Search Engine Providers) whose distance from the terminal device meets a first preset condition, identifying them as roaming SMFs. The roaming NRF sends the terminal device's location information to the home NRF via a network element discovery request message. The home NRF then queries its home network for SMFs whose distance from the terminal device meets a second preset condition, identifying them as home SMFs.

[0190] In one example, the roaming NRF queries the roaming network to find the nearest SMF to the terminal device and identifies it as the roaming SMF. The home NRF queries the home network to find the nearest SMF to the terminal device based on the terminal device's location information and identifies it as the home SMF.

[0191] It should be noted that in Case 1, cross-PLMN signaling messages (such as network element discovery request messages) need to carry the terminal device's TAI. Therefore, these cross-PLMN signaling messages need to be adjusted to carry the terminal device's TAI. Similarly, since these signaling messages need to be relayed between the home network and the roaming network via the roaming NRF, roaming SEPP, home SEPP, and home NRF, the roaming NRF, roaming SEPP, home SEPP, and home NRF also need to be enhanced to recognize the terminal device's TAI in the aforementioned cross-PLMN signaling messages and to correctly route the cross-PLMN signaling messages.

[0192] In addition, when the home SMF initiates registration with the home NRF, the home SMF also needs to register the SMF's TA information with the home NRF.

[0193] Scenario 2: Location information of the terminal device. The service area of ​​the roaming network element corresponding to the terminal device.

[0194] In scenario 2, the roaming NRF determines the service area of ​​the roaming AMF corresponding to the terminal device based on the service area of ​​the roaming network element corresponding to the terminal device; the roaming NRF selects the SMF in the roaming network that has the same (or similar) service area as the roaming AMF based on the service area of ​​the roaming AMF.

[0195] The roaming NRF sends the service area of ​​the roaming network element corresponding to the terminal device to the home NRF via a network element discovery request message. The home NRF determines the service area of ​​the roaming SMF corresponding to the terminal device based on the service area of ​​the roaming network element corresponding to the terminal device; the home NRF then selects an SMF in the home network with the same (or similar) service area as the home SMF based on the service area of ​​the roaming SMF.

[0196] In one example, when SMFs are set up on a province-by-province basis, the roaming NRF determines the province where the terminal device is currently located, or the province to which the roaming AMF corresponding to the terminal device belongs. The roaming NRF identifies the SMF in the roaming network that belongs to the same province as the roaming AMF as the roaming SMF. The home NRF identifies the SMF in the home network that is set to the same province as the roaming AMF or roaming SMF as the home SMF.

[0197] As an example, the format of a serving scope is: province label.vPLMN ID. 3GPP.NETWORK.

[0198] It should be noted that in Case 1, cross-PLMN signaling messages (such as network element discovery request messages) need to carry the service area of ​​the corresponding roaming network element of the terminal device. Therefore, these cross-PLMN signaling messages need to be adjusted to carry the service area of ​​the corresponding roaming network element of the terminal device. Similarly, since these signaling messages need to be relayed between the home network and the roaming network via the roaming NRF, roaming SEPP, home SEPP, and home NRF, the roaming NRF, roaming SEPP, home SEPP, and home NRF also need to be enhanced to identify the service area of ​​the corresponding roaming network element of the terminal device in the aforementioned cross-PLMN signaling messages and to correctly route the cross-PLMN signaling messages.

[0199] In addition, when the home SMF initiates registration with the home NRF, the home SMF also needs to register the SMF's service area information with the home NRF.

[0200] Compared to Situation 2, Situation 1 uses the terminal device's TAI (Target Area Identity) as the granularity to represent the terminal device's location information, making the location information more accurate. Situation 2 uses the service area of ​​the roaming network element corresponding to the terminal device as the granularity to represent the terminal device's location information, eliminating the need to adjust the TAI and TAI List. This avoids the situation where the terminal device fails to establish a PDU session in the home network due to untimely updates and the inability to discover the home SMF.

[0201] As can be seen, the above mainly describes the technical solutions provided by the embodiments of this application from a methodological perspective. To achieve the above functions, it includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, in conjunction with the modules and algorithm steps of the various examples described in the embodiments disclosed herein, the embodiments of this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention.

[0202] This application embodiment can divide the network element discovery device into functional modules according to the above method example. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. Optionally, the module division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0203] like Figure 10 The diagram shown is a structural schematic of a network element discovery device provided in an embodiment of this application. The network element discovery device includes a communication unit 1001 and a processing unit 1002.

[0204] The system includes a communication unit 1001 and a processing unit 1002. The communication unit 1001 receives a PDU session establishment request from a terminal device, wherein the PDU session establishment request includes the location information of the terminal device. The network element discovery device is a core network device in the roaming network of the terminal device. The processing unit 1002 determines the home SMF and the roaming SMF based on the location information. The roaming SMF is the SMF in the roaming network, and the home SMF is the SMF in the home network. The roaming SMF acquires the service data of the terminal device and forwards the service data to the home SMF. The home SMF receives the service data from the roaming SMF and processes the service data of the terminal device.

[0205] Optionally, the processing unit 1002 is specifically configured to: generate a network element discovery request message based on the PDU session establishment request; the network element discovery request message includes the location information of the terminal device; instruct the communication unit 1001 to send the network element discovery request message to the roaming NRF; the roaming NRF is an NRF in the roaming network; instruct the communication unit 1001 to receive a network element discovery response message from the roaming NRF; the network element discovery response message is used to indicate at least one of the home SMF and the roaming SMF.

[0206] Optionally, the network element discovery response message is used to indicate the roaming SMF; the roaming SMF is the SMF in the roaming network whose location with the terminal device meets the first preset condition as determined by the roaming NRF; the network element discovery response message is the network element discovery response message generated by the roaming NRF based on the roaming SMF.

[0207] Optionally, the network element discovery response message is used to indicate the home SMF; the home SMF is the SMF in the home network determined by the home NRF after the roaming NRF forwards the network element discovery request message to the home NRF, which satisfies the second preset condition with respect to the location information of the terminal device; the network element discovery response message is the network element discovery response message generated by the home NRF based on the home SMF.

[0208] Optionally, the processing unit 1002 is also configured to: determine the roaming NRF based on the NRF address information configured in the network element discovery device.

[0209] Optionally, the processing unit 1002 is further configured to: generate a first slice selection request message; the first slice selection request message includes Single Network Slice Selection Assist Information (S-NSSAI) mapped by the terminal device in the roaming network; instruct the communication unit 1001 to send the first slice selection request message to the roaming NSSF; the roaming NSSF is an NSSF in the roaming network; instruct the communication unit 1001 to receive a first slice selection response message from the roaming NSSF; the first slice selection response message is used to indicate the NRF corresponding to S-NSSAI in the roaming network; and determine that the NRF indicated by the first slice selection response message is a roaming NRF.

[0210] Optionally, the processing unit 1002 is further configured to: determine the home network information of the terminal device; and determine the home NRF based on the home network information of the terminal device.

[0211] Optionally, the home NRF is the NRF in the home network determined by the home network information of the terminal device; the roaming NRF is the roaming NRF determined by the network element discovery device based on the NRF address information configured in the network element discovery device.

[0212] Optionally, the processing unit 1002 is further configured to: generate a second slice selection request message; the second slice selection request message includes Single Network Slice Selection Assistance Information (S-NSSAI) mapped by the terminal device in the roaming network, and a first identifier; the first identifier is used to characterize that the second slice request message is used to establish a PDU session for the terminal device in the home network; instruct the communication unit 1001 to send the second slice selection request message to the roaming NSSF; instruct the communication unit 1001 to receive a second slice selection response message from the roaming NSSF, the second slice selection response message being used to indicate the NRF in the home network corresponding to S-NSSAI; and determine that the NRF indicated by the second slice selection response message is the home NRF.

[0213] Optionally, the home NRF is the NRF determined by the roaming NSSF in the home network based on S-NSSAI after the roaming NSSF forwards the second slice selection request message to the home NSSF; the home NSSF is the NSSF in the home network; and the second slice selection response message is the slice selection response message generated by the home NSSF based on the home NRF.

[0214] Optionally, the home NSSF is the roaming NSSF determined by the PLMN identifier of the terminal device's home network.

[0215] Optionally, when the NRF in the home network is a hierarchically configured NRF, the home SMF is the SMF in the home network that meets the first preset condition determined by the secondary NRF based on the location information after the home NRF forwards the network element discovery request message to the secondary NRF; the secondary NRF is the next level NRF of the home NRF; and the network element discovery response message is the network element discovery request message generated by the secondary NRF based on the home SMF.

[0216] Optionally, the location information of the terminal device includes at least one of the following: the tracking area identifier (TAI) of the terminal device; the service area of ​​the roaming network element corresponding to the terminal device; the roaming network element includes at least one of roaming AMF and roaming SMF.

[0217] The processing unit can be a processor or a controller. It can implement or execute various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor can also be a combination of functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc. The communication unit can be a transceiver circuit or a communication interface, etc. The storage module can be a memory. When the processing unit is a processor, the communication unit is a communication interface, and the storage module is a memory, the network element discovery device involved in the embodiments of this application can be... Figure 1 The network element discovery device shown.

[0218] Through the above description of the implementation methods, those skilled in the art will clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the network node can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, modules, and network nodes described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0219] This application also provides a computer-readable storage medium storing instructions. When a computer executes these instructions, the computer performs each step of the method flow shown in the above-described method embodiments.

[0220] This application also provides a chip, which includes a processor and a communication interface. The communication interface and the processor are coupled. The processor is used to run computer programs or instructions to implement the network element discovery method in the above method embodiments.

[0221] Embodiments of this application provide a computer program product containing instructions that, when executed on a computer, cause the computer to perform the network element discovery method in the above method embodiments.

[0222] The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), registers, hard disks, optical fibers, compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing, or any other form of computer-readable storage medium in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium may also be a component of the processor. The processor and the storage medium may reside in an application-specific integrated circuit (ASIC). In embodiments of the present invention, a computer-readable storage medium may be any tangible medium that contains or stores a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.

[0223] Since the apparatus, device, computer-readable storage medium, and computer program product in the embodiments of the present invention can be applied to the above methods, the technical effects that can be obtained can also be referred to the above method embodiments. The embodiments of this application will not be repeated here.

[0224] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for network element discovery, characterized in that, include: The core network device receives a PDU session establishment request from a terminal device; wherein, the PDU session establishment request includes the location information of the terminal device; and the core network device is the core network device in the roaming network of the terminal device. The core network equipment determines the home SMF and roaming SMF based on the location information, including: The core network device generates a network element discovery request message based on the PDU session establishment request; the network element discovery request message includes the location information of the terminal device; The core network device sends the network element discovery request message to the roaming NRF; the roaming NRF is the NRF in the roaming network; The core network device receives a network element discovery response message from the roaming NRF; the network element discovery response message is used to indicate the home SMF and the roaming SMF, or the network element discovery response message is used to indicate the home SMF; Wherein, the roaming SMF is the SMF in the roaming network, and the home SMF is the SMF in the home network; the roaming SMF is used to acquire the service data of the terminal device and forward the service data of the terminal device to the home SMF; the home SMF is used to receive the service data of the terminal device from the roaming SMF and process the service data of the terminal device. The roaming SMF is the SMF in the roaming network whose location relative to the terminal device satisfies a first preset condition, as determined by the roaming NRF; The network element discovery response message is the network element discovery response message generated by the roaming NRF based on the roaming SMF; The home SMF is the SMF in the home network whose location information with the terminal device satisfies the second preset condition, as determined by the home NRF after the roaming NRF forwards the network element discovery request message to the home NRF. The network element discovery response message is a network element discovery response message generated by the home NRF based on the home SMF; The location information of the terminal device includes at least one of the following: the tracking area identifier (TAI) of the terminal device; the service area of ​​the roaming network element corresponding to the terminal device; and the roaming network element includes at least one of roaming AMF and roaming SMF.

2. The method according to claim 1, characterized in that, Before the core network device sends the network element discovery request message to the roaming NRF, the method further includes: The core network device determines the roaming NRF based on the NRF address information configured in the core network device.

3. The method according to claim 1, characterized in that, Before the core network device sends the network element discovery request message to the roaming NRF, the method further includes: The core network device generates a first slice selection request message; the first slice selection request message includes Single Network Slice Selection Assist Information (S-NSSAI) mapped by the terminal device in the roaming network; The core network device sends the first slice selection request message to the roaming NSSF; the roaming NSSF is the NSSF in the roaming network; The core network device receives a first slice selection response message from the roaming NSSF; the first slice selection response message is used to indicate the NRF corresponding to the S-NSSAI in the roaming network; The core network device determines that the NRF indicated by the first slice selection response message is the roaming NRF.

4. The method according to claim 1, characterized in that, Before the core network device sends the network element discovery request message to the roaming NRF, the method further includes: The core network equipment determines the network information of the terminal device; The core network device determines the home NRF based on the home network information of the terminal device.

5. The method according to claim 4, characterized in that, The home NRF is the NRF in the home network determined by the roaming NRF based on the home network information of the terminal device; The roaming NRF is determined by the core network device based on the NRF address information configured in the core network device.

6. The method according to claim 1, characterized in that, Before the core network device sends the network element discovery request message to the roaming NRF, the method further includes: The core network device generates a second slice selection request message; the second slice selection request message includes Single Network Slice Selection Assist Information (S-NSSAI) mapped by the terminal device in the roaming network, and a first identifier; the first identifier is used to indicate that the second slice selection request message is used to establish a PDU session for the terminal device in the home network; The core network device sends the second slice selection request message to the roaming NSSF; The core network device receives a second slice selection response message from the roaming NSSF, the second slice selection response message being used to indicate the NRF in the home network corresponding to the S-NSSAI; The core network device determines that the NRF indicated by the second slice selection response message is the home NRF.

7. The method according to claim 6, characterized in that, The home NRF is the NRF determined by the home NSSF in the home network based on the S-NSSAI after the roaming NSSF forwards the second slice selection request message to the home NSSF; the home NSSF is the NSSF in the home network. The second slice selection response message is the slice selection response message generated by the home NSSF based on the home NRF.

8. The method according to claim 7, characterized in that, The home NSSF is the roaming NSSF that the roaming NSSF determines in the home network based on the PLMN identifier of the home network of the terminal device.

9. The method according to any one of claims 4-8, characterized in that, When the NRF in the home network is a hierarchical NRF, the home SMF is the SMF in the home network that meets the second preset condition determined by the second-level NRF based on the location information after the home NRF forwards the network element discovery request message to the second-level NRF; The secondary NRF is the next level NRF after the parent NRF; The network element discovery response message is generated by the secondary NRF based on the home SMF.

10. A network element discovery device, characterized in that, include: Communication unit and processing unit; The communication unit is used to receive a PDU session establishment request from a terminal device; wherein the PDU session establishment request includes the location information of the terminal device; and the network element discovery device is a core network device in the roaming network of the terminal device. The processing unit is used to determine the home SMF and the roaming SMF based on the location information; Specifically, the processing unit is used for: Based on the PDU session establishment request, a network element discovery request message is generated; the network element discovery request message includes the location information of the terminal device. The communication unit is instructed to send the network element discovery request message to the roaming NRF; the roaming NRF is the NRF in the roaming network; The communication unit is instructed to receive a network element discovery response message from the roaming NRF; the network element discovery response message is used to indicate the home SMF and the roaming SMF, or the network element discovery response message is used to indicate the home SMF; Wherein, the roaming SMF is the SMF in the roaming network, and the home SMF is the SMF in the home network; the roaming SMF is used to acquire the service data of the terminal device and forward the service data of the terminal device to the home SMF; the home SMF is used to receive the service data of the terminal device from the roaming SMF and process the service data of the terminal device. The roaming SMF is the SMF in the roaming network whose location relative to the terminal device satisfies a first preset condition, as determined by the roaming NRF; The network element discovery response message is the network element discovery response message generated by the roaming NRF based on the roaming SMF; The home SMF is the SMF in the home network whose location information with the terminal device satisfies the second preset condition, as determined by the home NRF after the roaming NRF forwards the network element discovery request message to the home NRF. The network element discovery response message is a network element discovery response message generated by the home NRF based on the home SMF; The location information of the terminal device includes at least one of the following: the tracking area identifier (TAI) of the terminal device; the service area of ​​the roaming network element corresponding to the terminal device; and the roaming network element includes at least one of roaming AMF and roaming SMF.

11. The apparatus according to claim 10, characterized in that, The processing unit is further configured to: The roaming NRF is determined based on the NRF address information configured in the network element discovery device.

12. The apparatus according to claim 10, characterized in that, The processing unit is further configured to: Generate a first slice selection request message; the first slice selection request message includes Single Network Slice Selection Assist Information (S-NSSAI) mapped by the terminal device in the roaming network; The communication unit is instructed to send the first slice selection request message to the roaming NSSF; The roaming NSSF is the NSSF in the roaming network; The communication unit is instructed to receive a first slice selection response message from the roaming NSSF; The first slice selection response message is used to indicate the NRF corresponding to the S-NSSAI in the roaming network; The NRF indicated by the first slice selection response message is determined to be the roaming NRF.

13. The apparatus according to claim 10, characterized in that, The processing unit is further configured to: Determine the network information of the terminal device; The home network information of the terminal device is used to determine the home NRF.

14. The apparatus according to claim 13, characterized in that, The home NRF is the NRF in the home network determined by the roaming NRF based on the home network information of the terminal device; The roaming NRF is determined by the network element discovery device based on the NRF address information configured in the network element discovery device.

15. The apparatus according to claim 10, characterized in that, The processing unit is further configured to: A second slice selection request message is generated; the second slice selection request message includes Single Network Slice Selection Assist Information (S-NSSAI) mapped by the terminal device in the roaming network, and a first identifier; the first identifier is used to characterize that the second slice selection request message is used to establish a PDU session for the terminal device in the home network; The communication unit is instructed to send the second slice selection request message to the roaming NSSF; The communication unit is instructed to receive a second slice selection response message from the roaming NSSF, the second slice selection response message being used to indicate the NRF in the home network corresponding to the S-NSSAI; The NRF indicated by the second slice selection response message is determined to be the home NRF.

16. The apparatus according to claim 15, characterized in that, The home NRF is the NRF determined by the home NSSF in the home network based on the S-NSSAI after the roaming NSSF forwards the second slice selection request message to the home NSSF; the home NSSF is the NSSF in the home network. The second slice selection response message is the slice selection response message generated by the home NSSF based on the home NRF.

17. The apparatus according to claim 16, characterized in that, The home NSSF is the roaming NSSF that the roaming NSSF determines in the home network based on the PLMN identifier of the home network of the terminal device.

18. The apparatus according to any one of claims 13-17, characterized in that, When the NRF in the home network is a hierarchical NRF, the home SMF is the SMF in the home network that meets the second preset condition determined by the second-level NRF based on the location information after the home NRF forwards the network element discovery request message to the second-level NRF; The secondary NRF is the next level NRF after the parent NRF; The network element discovery response message is generated by the secondary NRF based on the home SMF.

19. An electronic device, characterized in that, include: A processor and a memory; wherein the memory is used to store computer execution instructions, and when the electronic device is running, the processor executes the computer execution instructions stored in the memory to cause the electronic device to perform the network element discovery method according to any one of claims 1-9.

20. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes instructions that, when executed by an electronic device, cause the computer to perform the network element discovery method as described in any one of claims 1-9.

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