User plane network element determination method and apparatus, and device

Abstract

The present application provides a user plane network element determination method and apparatus, and a device. In the method: when a first session management network element receives a session establishment request message sent by a first access management network element, the first session management network element can perform a process of establishing a session for a first terminal, and, in the process of establishing the session for the first terminal, can determine a target user plane function of the first terminal. When determining the user plane function of the first terminal, the first session management network element can learn about a user plane function previously determined for a second terminal by a network side. A pairing identifier of the first terminal is the same as a pairing identifier of the second terminal, that is, the first terminal and the second terminal are two terminals in a pair of paired terminals, and the first session management network element can directly determine the user plane function of the second terminal as the target user plane function of the first terminal, so that the purpose of causing the two terminals among the paired terminals to select a same user plane function is achieved.

Description

Method, device and equipment for determining user plane network element

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on February 9, 2024, with application number 202410179162.X and application name "A method, device and equipment for determining user-plane network elements", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of data processing technology, and in particular to a method, apparatus and device for determining a user plane network element. Background Art

[0004] In wireless networks, dual-transmit selective reception can be achieved by connecting both terminals in a pair to the wireless side, establishing two concurrent data links. The data transmitter duplicates the data and sends it over two links (this is "dual transmission"). The two terminals in the pair ultimately converge at the same processing point responsible for dual-transmit selective reception. The data receiver prioritizes the first-arrived data and discards the redundant data that arrives later (this is "selective reception"). Compared to single-link transmission, dual-transmit selective reception has the following advantages:

[0005] High reliability: Dual transmission means that even if a single link loses packets or fails, data is still backed up, ensuring uninterrupted services.

[0006] Low latency: Selective collection means first-come, first-served, preferentially utilizing resources from two links to ensure low latency for services.

[0007] From the above description of dual-transmission selective reception, it can be seen that the two terminals in the paired terminals need to eventually converge to the same processing point responsible for dual-transmission selective reception in order to realize the dual-transmission selective reception function. Taking the user plane function (UPF) as an example of the processing point responsible for dual-transmission selective reception, in the relevant technology, in order to ensure that the two terminals in the paired terminals are selected to the same UPF, only one UPF supporting dual-transmission selective reception can be deployed in the 2B industrial park, etc., because there is only one UPF supporting dual-transmission selective reception, so the two terminals in the paired terminals will inevitably select the same UPF. However, if only one UPF supporting dual-transmission selective reception is deployed, if the UPF fails, there is no disaster recovery UPF that can take over the dual-transmission selective reception. Therefore, it is very necessary to deploy multiple UPFs supporting dual-transmission selective reception to improve the reliability of wireless network services.

[0008] However, when multiple UPFs supporting dual-transmit selective reception services are deployed, there is currently no solution to ensure that two terminals in a paired terminal can select the same UPF. Summary of the Invention

[0009] The embodiments of the present application provide a method, apparatus and device for determining a user plane network element, which is used to select two terminals in a paired terminal to the same UPF when multiple UPFs supporting dual-transmission and selective reception services are deployed.

[0010] In a first aspect, an embodiment of the present application provides a method for determining a user plane function network element, which can be performed by a first session management network element. In this method:

[0011] Upon receiving the session establishment request message sent by the first access management network element, the first session management network element may establish a session for the first terminal, and during the process of establishing the session for the first terminal, may determine the user plane function network element of the first terminal. Specifically, when determining the user plane function network element of the first terminal, the first session management network element may first determine the user plane function network element previously determined by the network side for the second terminal. Wherein, the pairing identifier of the first terminal is the same as the pairing identifier of the second terminal, that is, the first terminal and the second terminal are two terminals in a pair of paired terminals. The first session management network element may directly determine the user plane function network element of the second terminal as the target user plane function network element for the first terminal.

[0012] Through the above method, the first session management network element can determine the user plane function network element previously determined by the network side for the second terminal as the user plane function network element of the first terminal, thereby achieving the purpose of selecting the two terminals in the paired terminals to the same user plane function network element.

[0013] In one possible implementation, when determining the user plane function network element of the second terminal, the first session management network element may first obtain the correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal (a first correspondence), and determine the user plane function network element of the second terminal through this correspondence.

[0014] Through the above method, the first session management network element can accurately obtain the user plane function network element previously determined by the network side for the second terminal by obtaining the correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element, thereby achieving the purpose of selecting the two terminals in the paired terminals to the same user plane function network element.

[0015] In one possible implementation, when the first session management network element obtains the correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal (target user plane function network element), the first session management network element may obtain the correspondence through two approaches. The first approach is to obtain the correspondence locally from the first session management network element; the second approach is to obtain the correspondence from the data management network element by interacting with the data management network element. For example, the first session management network element may send a contract information acquisition message to the data management network element to obtain the first contract information of the first terminal, and the data management network element may return the first contract information of the first terminal to the first session management network element. The first contract information may include the correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal.

[0016] Through the above method, the first session management network element can quickly and accurately obtain the correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal, so that based on the correspondence, it can accurately obtain the user plane function network element previously determined by the network side for the second terminal, thereby achieving the purpose of selecting the two terminals in the paired terminals to the same user plane function network element.

[0017] In one possible implementation, when the first session management network element locally stores the correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal, it may be that in the process of establishing a session for the second terminal, the first session management network element randomly selects a user plane function network element, determines the user plane function network element as the user plane function network element of the second terminal, and stores the correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element.

[0018] In the above manner, the first session management network element can quickly, flexibly and accurately obtain the correspondence between the pairing identifier of the second terminal and the identifier of the target user plane function network element, and save the correspondence locally.

[0019] In one possible implementation, after determining the user plane function network element of the second terminal, the first session management network element may also send a first registration message to the data management network element. The first registration message includes the correspondence between the pairing identifier of the second terminal and the identifier of the first session management network element. After receiving the first registration message, the data management network element may save the correspondence between the pairing identifier of the second terminal and the identifier of the first session management network element.

[0020] Through the above method, the data management network element can save the correspondence between the pairing identifier of the second terminal and the identifier of the first session management network element. Later, when the first terminal goes online, the access management network element of the first terminal can obtain the correspondence from the data management network element, so that the first terminal can also be selected to the first session management network element, so that the first terminal and the second terminal are both selected to the same session management network element. The session management network element (first session management network element) can also determine the target user plane function network element previously determined for the second terminal as the target user plane function network element of the first terminal, thereby achieving the purpose of selecting the two terminals in the paired terminals to the same target user plane function network element.

[0021] In one possible implementation, after the first session management network element determines the target user plane function network element for the first terminal, it may further send the pairing identifier of the first terminal to the target user plane function network element. Furthermore, the pairing identifier of the second terminal may also be sent to the target user plane function network element via the first session management network element or the second session management network element.

[0022] In the above manner, the target user plane functional network element can perform dual transmission, selective reception and forwarding processes on the message of the first terminal and the message of the second terminal according to the pairing identifier of the first terminal and the pairing identifier of the second terminal.

[0023] In a second aspect, an embodiment of the present application provides a method for determining a user plane function network element, which can be performed by a first access management network element. In this method:

[0024] Upon receiving a first registration request message from a first terminal, the first access management network element may register the first terminal. When registering the first terminal, the first access management network element may first determine a session management network element for the first terminal. Specifically, when determining the session management network element for the first terminal, the first access management network element may first determine a session management network element previously determined by the network side for the second terminal. Wherein, the pairing identifier of the first terminal is the same as the pairing identifier of the second terminal, i.e., the first terminal and the second terminal are two terminals in a pair of paired terminals. The first access management network element may directly determine the session management network element of the second terminal as the session management network element of the first terminal, so that both the first terminal and the second terminal are selected to the same session management network element.

[0025] In one possible implementation, when the first access management network element determines the session management network element of the second terminal, the first access management network element can obtain the correspondence between the pairing identifier of the second terminal and the identifier of the session management network element of the second terminal from the data management network element, and can determine the session management network element of the second terminal based on the correspondence.

[0026] The beneficial effects of the second aspect and its various possible implementations can refer to the beneficial effects of the first aspect and its various possible implementations, and will not be repeated here.

[0027] In a third aspect, embodiments of the present application provide a method for determining a user plane function network element, which can be performed by a data management network element. In this method, upon receiving a second registration message sent by a second session management network element, the data management network element can obtain a correspondence between a pairing identifier of a second terminal and an identifier of a target user plane function network element included in the second registration message, and save the correspondence.

[0028] The beneficial effects of the third aspect can refer to the beneficial effects of the first aspect and its various possible implementation methods, and will not be repeated here.

[0029] In a fourth aspect, the present application provides a method for determining a user plane function network element, which can be performed by a data management network element, wherein:

[0030] If the data management network element identifies that the pairing identifier of the first terminal is the same as the pairing identifier of the second terminal, but the first session management network element of the first terminal is different from the second session management network element of the second terminal, or the user plane function network element of the first terminal is different from the user plane function network element of the second terminal, the data management network element can send a terminal re-online indication to the first access management network element or to the first session management network element, and the terminal re-online indication can be used to instruct the first terminal to be put back online.

[0031] By using the above method, the purpose of selecting the first terminal and the second terminal to the same user plane function network element can be achieved when the first terminal comes back online.

[0032] In a possible implementation, the terminal back online indication may carry the terminal identifier and the pairing identifier of the first terminal.

[0033] Through the above method, based on the terminal identifier and pairing identifier of the first terminal carried in the terminal re-online indication, the first terminal can be quickly and accurately taken offline and put back online, so that during the process of the first terminal coming back online, the two terminals in the paired terminals can be quickly and accurately selected to the same target user plane functional network element.

[0034] In a fifth aspect, the present application provides a method for determining a user plane function network element, which can be performed by a first session management network element, wherein:

[0035] When the first session management network element identifies that the first user plane function network element of the first terminal is different from the second user plane function network element of the second terminal, and the pairing identifier of the first terminal is the same as the pairing identifier of the second terminal, in order to adjust the user plane function network elements of the two terminals in the paired terminals to the same target user plane function network element, the first session management network element may change the user plane function network element of the first terminal to the user plane function network element of the second terminal.

[0036] In the above manner, the first session management network element can achieve the purpose of selecting the same target user plane function network element for the two paired terminals by changing the user plane function network element of the first terminal to the user plane function network element of the second terminal.

[0037] In a sixth aspect, the present application provides a communication device comprising a unit or module for executing the method as described in any one of the first to fifth aspects above.

[0038] In a seventh aspect, the present application provides a communication device comprising one or more processors configured to execute the method as described in any one of the first to fifth aspects.

[0039] In an eighth aspect, the present application provides a communication system, comprising: the first session management network element described in any one of the first aspects and the first access management network element described in any one of the second aspects.

[0040] In the ninth aspect, the present application also provides a communication system, comprising: the first session management network element described in any one of the first aspects, the first access management network element described in any one of the second aspects, and the data management network element described in the third aspect.

[0041] In the tenth aspect, the present application provides a computer-readable storage medium, which stores a computer program or instruction. When the computer program or instruction is executed by a communication device, it implements the method described in any one of the first to fifth aspects.

[0042] In the eleventh aspect, the present application provides a chip system, comprising: a memory for storing a computer program; a processor; when the processor calls and runs the computer program from the memory, the communication device equipped with the chip system executes any method described in any one of the first to fifth aspects.

[0043] In a twelfth aspect, a computer program product is provided, which, when called by a computer, enables the computer to execute any of the methods described in any of the first to fifth aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG1 is a schematic diagram of a 5G communication system architecture;

[0045] FIG2 is a schematic diagram of a communication system architecture applicable to an embodiment of the present application;

[0046] FIG3 is a flow chart of a method for determining a user plane function network element provided by the present application;

[0047] FIG4 is a flow chart of a method for resolving a conflict between a session management network element of a first terminal and a session management network element of a second terminal provided by the present application;

[0048] FIG5 is a flow chart of a method for resolving a conflict between a user plane function network element of a first terminal and a user plane function network element of a second terminal provided by the present application;

[0049] FIG6 is a flow chart of another method for resolving a conflict between a user plane function network element of a first terminal and a user plane function network element of a second terminal provided by the present application;

[0050] FIG7 is a flow chart of a method for determining a user plane function network element of a second terminal provided by the present application;

[0051] FIG8 is a schematic flow chart of a method for determining a user plane function network element of a first terminal provided by the present application;

[0052] FIG9 is a flow chart of a method for resolving a conflict between an SMF of a first terminal and an SMF of a second terminal provided by the present application;

[0053] FIG10 is a schematic flow chart of another method for determining the UPF of a second terminal provided by the present application;

[0054] FIG11 is a flow chart of another method for determining the UPF of a first terminal provided by the present application;

[0055] FIG12 is a flow chart of a method for resolving a conflict between a UPF of a first terminal and a UPF of a second terminal provided by the present application;

[0056] FIG13 is a flow chart of a method for making a first terminal offline and back online provided by the present application;

[0057] FIG14 is a flow chart of a second method for making a first terminal offline and back online provided by the present application;

[0058] FIG15 is a flowchart of a third method for making a first terminal offline and back online provided by the present application;

[0059] FIG16 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0060] FIG17 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0061] The embodiments of the present application can be applied to various communication systems, such as long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), world-wide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) system or new radio (NR) or future communication system, etc., and the embodiments of the present application are not limited to this.

[0062] Figure 1 shows a schematic diagram of a 5G network architecture based on a service-oriented architecture (SA), developed by the 3rd Generation Partnership Project (3GPP). This 5G network architecture includes access network equipment and core network equipment. Terminals access the data network (DN) through these devices.

[0063] In Figure 1, the terminal may include various handheld devices with wireless communication capabilities, vehicle-mounted devices, wearable devices, computing devices, or other processing devices connected to a wireless modem. The terminal may also be referred to as a terminal device. Terminal may also refer to user equipment (UE), access terminal, subscriber unit, user agent, cellular phone, smart phone, wireless data card, personal digital assistant (PDA), tablet computer, wireless modem, handheld device (handset), laptop computer, smart point of sale (POS), customer-premises equipment (CPE), machine type communication (MTC) terminal, communication equipment carried by high-altitude aircraft, wearable device, drone, robot, terminal in D2D, terminal in vehicle to everything (V2X), virtual reality (VR) terminal device, augmented reality (AR) terminal device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical, wireless terminal in smart grid, wireless terminal in transportation security, etc. Safety), wireless terminals in smart cities, wireless terminals in smart homes, or terminal devices in future communication networks, etc.

[0064] In Figure 1, the access network equipment can be either a radio access network (RAN) or a wired access network. The RAN manages radio resources, provides access services to terminals, and forwards user data between terminals and the core network. The RAN can also be understood as a base station in the network.

[0065] Exemplarily, the access network device in the embodiment of the present application may be any communication device with wireless transceiver functions for communicating with a terminal. The access network equipment includes but is not limited to: evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home evolved NodeB (HeNB, or home Node B, HNB), baseband unit (BBU), access point (AP) in wireless fidelity (Wi-Fi) system, wireless relay node, wireless backhaul node, transmission point (TP) or transmission and reception point (TRP), etc., and can also be a 5G mobile communication system, such as a gNB in ​​the next generation wireless (NR) system, or a transmission point (TRP or TP), one or a group of (including multiple antenna panels) antenna panels of a base station in the 5G mobile communication system, or it can also be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU) or a distributed unit (DU), etc.

[0066] In some deployments, a gNB may include a centralized unit (CU) and a DU. The gNB may also include an active antenna unit (AAU). The CU implements some gNB functions, while the DU implements some gNB functions. For example, the CU is responsible for processing non-real-time protocols and services, implementing the functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers. The DU is responsible for processing physical layer protocols and real-time services, implementing the functions of the radio link control (RLC), media access control (MAC), and physical (PHY) layers. The AAU implements some physical layer processing functions, RF processing, and active antenna-related functions. RRC layer information is generated by the CU and ultimately encapsulated by the DU's PHY layer into PHY layer information, or is converted from PHY layer information. Therefore, in this architecture, higher-layer signaling, such as RRC layer signaling, can also be considered to be sent by the DU, or by a combination of the DU and the AAU. It is understood that the access network device may be a device including one or more of a CU node, a DU node, and an AAU node. In addition, the CU may be classified as an access network device in the access network, or as an access network device in the core network (CN), which is not limited in this application.

[0067] Access network equipment and terminals can be fixed or mobile. They can be deployed on land, indoors or outdoors, handheld or vehicle-mounted; on water; or in the air on aircraft, balloons, and satellites.

[0068] In Figure 1, the core network equipment may include: unified data management (UDM) network element, access and mobility management function (AMF) network element, session management function (SMF) network element, policy control function (PCF) network element, application function (AF) network element, user plane function (UPF) network element, network exposure function (NEF) network element, network repository function (NRF) network element, network slice selection function (NSSF) network element, authentication server function (AUSF) network element, etc. These functional units can work independently or be combined to implement certain control functions. For example, AMF, SMF and PCF can be combined together as a management device to complete access control and mobility management functions such as access authentication, security encryption, and location registration of terminal devices, as well as session management functions such as establishment, release and change of user plane transmission paths, as well as the function of analyzing some slice-related data (such as congestion) and terminal device-related data.

[0069] UPF: As the interface with the data network, it performs functions such as user plane data forwarding, session / flow-level billing statistics, bandwidth limiting, etc., namely packet routing and forwarding, and quality of service (QoS) processing of user plane data.

[0070] AMF: Mainly performs functions such as mobility management and access authentication / authorization. In addition, it is responsible for transmitting user policies between terminals and policy control function (PCF) network elements.

[0071] SMF: Mainly used for session management after user access, including protocol data unit (PDU) session establishment, modification, activation, deactivation, and release, as well as UE IP address allocation, dynamic host configuration protocol (PDCH) v4 / v6 functions, Address Resolution Protocol (ARP) proxy, IPv6 Neighbor Solicitation Proxying for Ethernet PDU, selection and control of user plane, determination of session SSC mode and roaming functions.

[0072] PCF: Mainly used to manage network behavior with a unified policy framework, provide policy rules to control plane network elements (such as AMF, SMF) and access contract information related to policy decisions in the unified data repository (UDR).

[0073] UDM: Mainly used for generating 3GPP AKA authentication certificates, User ID processing, access authorization based on contract information, service NF registration management, contract information management and other function-related data unified management.

[0074] Data network (DN): Provides services such as carrier services, internet access, or third-party services. It includes servers that perform tasks like video source encoding and rendering. A DN is a combination of data terminal equipment, data processing equipment, and data communication equipment (including communication channels). It provides data transmission and resource sharing, including data and data processing capabilities, for distributed communication stations and users.

[0075] The 5G core network may also include a controller, which may also be called a management server or network management server. The controller is used to manage and control satellite-borne devices or ground network elements, including but not limited to the distribution of configurations and table entries.

[0076] In Figure 1, Npcf, Nudr, Nudm, Naf, Namf, and Nsmf are service-oriented interfaces provided by the PCF, UDR, UDM, AF, AMF, and SMF, respectively, for invoking corresponding service-oriented operations. N1, N2, N3, N4, and N6 are interface serial numbers, and their meanings are as follows:

[0077] 1) N1 interface: The interface between the AMF and the UE, which can be used to deliver non-access stratum (NAS) signaling (such as QoS rules from the AMF) to the UE.

[0078] 2) N2 interface: The interface between AMF and RAN, which can be used to transmit radio bearer control information from the core network side to the RAN.

[0079] 3) N3 interface: The interface between RAN and UPF, mainly used to transmit uplink and downlink user plane data between RAN and UPF.

[0080] 4) N4 interface: The interface between SMF and UPF, which can be used to transmit information between the control plane and the user plane, including controlling the issuance of forwarding rules, QoS rules, traffic statistics rules, etc. for the user plane and reporting information on the user plane.

[0081] 5) N6 interface: The interface between UPF and DN, used to transmit uplink and downlink user data flows between UPF and DN.

[0082] It should be noted that the part shown in Figure 1 is only an exemplary architecture diagram. In addition to the network elements or functional entities shown in Figure 1, the network architecture can also include other network elements or functional entities, which is not limited in the embodiments of the present application.

[0083] It should be understood that the interface names between network elements in this application are merely exemplary, and the interfaces between network elements may also have other names. The embodiments of this application do not limit the names of the interfaces.

[0084] It should be understood that the embodiments of the present application can be applied to future communication systems, such as 6G systems. When the embodiments of the present application are applied to future communication systems, the names of terminal devices, access network devices, core network devices with sensing functions, and devices with other functions may change, and the embodiments of the present application do not limit this. For ease of understanding, the following text uses the application of the embodiments of the present application in a 5G system as an example to introduce specific solutions.

[0085] In current technology, to ensure that both paired terminals select the same UPF, only one UPF supporting dual-transmission and selective reception can be deployed in a 2B industrial park, for example. However, if only one UPF supporting dual-transmission and selective reception is deployed, if that UPF fails, there is no disaster recovery UPF to take over. Therefore, it is necessary to deploy multiple UPFs supporting dual-transmission and selective reception to improve the reliability of wireless network services. However, when multiple UPFs supporting dual-transmission and selective reception are deployed, there is currently no solution to ensure that both paired terminals can select the same UPF.

[0086] Based on this, the present application proposes a method, apparatus and device for determining a user plane network element, which can select two terminals in a paired terminal to the same UPF when multiple UPFs supporting dual-transmission and selective reception services are deployed.

[0087] In order to better describe the embodiments of the present application, the following describes the methods provided by the embodiments of the present application in conjunction with the accompanying drawings. Unless otherwise specified, the steps indicated by dotted lines in the accompanying drawings corresponding to the various embodiments of the present application are all optional steps.

[0088] The following is an introduction to the various terms involved in this application:

[0089] The first terminal and the second terminal are two terminals in a paired terminal pair. The pairing identifier of the first terminal is the same as the pairing identifier of the second terminal. The pairing identifier can be used to identify which two terminals belong to a paired terminal pair. Two terminals with the same pairing identifier are both terminals in the paired terminal pair. The terminal pairing identifier can be assigned to the terminal by the network side. Information such as the terminal pairing identifier can be stored in a data management network element, etc.

[0090] For the convenience of description, the access management network element of the first terminal is referred to as the first access management network element. In other words, it can also be referred to as: the access management network element registered for the first terminal is the first access management network element, the first access management network element serves the first terminal, the access management network element serving the first terminal is the first access management network element, or the access management network element connected to the first terminal is the first access management network element.

[0091] The access management network element of the second terminal is called the second access management network element. Similarly, it can also be called: the access management network element registered for the second terminal is the second access management network element, the second access management network element serves the second terminal, the access management network element serving the second terminal is the second access management network element, or the access management network element connected to the second terminal is the second access management network element.

[0092] Among them, the first access management network element and the second access management network element can be the same or different, and this application does not make any specific limitations on this.

[0093] The session management network element of the first terminal is called the first session management network element. In other words, it can also be called: the session management network element registered for the first terminal is the first session management network element, the first session management network element serves the first terminal, the session management network element serving the first terminal is the first session management network element, or the session management network element connected to the first terminal is the first session management network element.

[0094] In the present application, the session management network element of the second terminal can be the first session management network element or the second session management network element. When the session management network element of the second terminal is the first session management network element, the session management network element of the first terminal and the session management network element of the second terminal are the same session management network element. When the session management network element of the second terminal is the second session management network element, the session management network element of the first terminal and the session management network element of the second terminal are two different session management network elements.

[0095] In addition, the user plane function network element of the terminal can also be called: a user plane function network element registered for the terminal, a user plane function network element serving the terminal, a user plane function network element serving the terminal, or a user plane function network element connected to the terminal.

[0096] The methods provided in the various embodiments of the present application can be applied to the network architecture shown in Figure 1 or other network architectures. The methods provided in the various embodiments of the present application can also be applied to the network architecture shown in Figure 2 or other network architectures. Please refer to Figure 2. The paired terminals (the first terminal and the second terminal) can be customer premises equipment (CPE). For example, the first terminal and the second terminal can be CPE1 and CPE2 respectively. The end-side networking can be connected to CPE1 and CPE2 respectively through a dual-transmitter and selective receiver switch. In addition, the redundant central processing unit (CPU) can be connected to each module in the dual module group through the built-in dual module group of the industrial gateway. The dual module group can be considered as a paired terminal. For example, the 5G LAN module 1 in the dual module group can be considered as the first terminal, and the 5G LAN module 2 in the dual module group can be considered as the second terminal.

[0097] The two terminals in a paired terminal pair can access the wireless side through different frequencies through static configuration or network-assisted frequency selection, establishing two links that can transmit data concurrently. Multiple user plane function network elements that support dual transmission and selective reception can be deployed in 2B industrial parks, such as the first user plane function network element (UPF1) and the second user plane function network element (UPF2). The two terminals in the same pair of paired terminals need to be registered (selected) with the same user plane function network element. Different pairs of paired terminals can be registered with the same user plane function network element or with different user plane function network elements.

[0098] In the embodiments of the present application, the control plane network element may be an SMF, AMF, etc. The user plane network element may be a UPF, etc. The data service network element may be a UDR, UDM, NRF, USDF, etc. For ease of understanding, the embodiments of the present application take the SMF as the session management network element, the AMF as the access management network element, the UPF as the user plane function network element, and the UDM as the data management network element as an example to explain the method for determining the user plane function network element provided in the present application.

[0099] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0100] FIG3 shows a flow chart of a method for determining a user plane function network element according to an embodiment of the present application. As shown in FIG3 , the flow may include the following steps:

[0101] Step 301: A first access management network element sends a session establishment request message to a first session management network element. The session establishment request message may include a terminal identifier of a first terminal. The session establishment request message is used to request establishment of a session for the first terminal.

[0102] When one of the paired terminals goes online, such as the first terminal goes online, the first terminal may initiate a registration request message, which may carry the terminal identifier of the first terminal (also referred to as the user identifier of the first terminal).

[0103] Upon receiving a registration request message (hereinafter referred to as a first registration request message for ease of description) initiated by a first terminal, a wireless (base station) may randomly select an access management network element (NE) that is registered (serving) the first terminal and send the first registration request message to the access management network element. For ease of description, the access management network element that is registered with the first terminal is referred to as the first access management network element.

[0104] After receiving the first registration request message from the first terminal, the first access management network element registers the first terminal. When registering the first terminal, the first access management network element may first determine a session management network element for the first terminal. When determining the session management network element for the first terminal, the first access management network element may use the session management network element of the second terminal as the session management network element for the first terminal (applicable to the case where the second terminal registers before the first terminal), or may randomly determine a session management network element for the first terminal.

[0105] The following describes two cases of determining the session management network element of the first terminal for the first access management network element:

[0106] The first method is to use the session management network element of the second terminal as the session management network element of the first terminal.

[0107] To ensure that the session management network element of the first terminal and the session management network element of the second terminal are the same session management network element (referred to as the first session management network element for ease of description), the first access management network element needs to know which access management network element is the session management network element of the second terminal. To know (obtain) the session management network element of the second terminal, the first access management network element can interact with the data management network element to obtain the session management network element previously determined by the network side for the second terminal from the data management network element.

[0108] In an embodiment of the present application, when any terminal initiates a registration request message, during the process of registering the terminal, the data management network element will save the correspondence between the pairing identifier of the terminal and the session management network element of the terminal. Therefore, the first access management network element can obtain the correspondence between the pairing identifier of the second terminal and the identifier of the first session management network element saved in the data management network element by interacting with the data management network element (for convenience of description, this correspondence is referred to as a second correspondence), and based on the second correspondence, obtain (learn) the session management network element previously determined by the network side for the second terminal.

[0109] The following describes a process in which the data management network element stores the correspondence between the pairing identifier of the terminal and the session management network element of the terminal, taking the second terminal as an example:

[0110] Step 0: The second terminal initiates a registration request message to the second access management network element.

[0111] Step 1: After receiving the registration request message, the second access management network element randomly determines a session management network element for the second terminal.

[0112] Step 2: The session management network element of the second terminal establishes a session for the second terminal and determines the user plane function network element of the second terminal.

[0113] The session management network element of the second terminal saves the correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal (for convenience of description, this correspondence is referred to as a first correspondence).

[0114] Step 3. The session management network element of the second terminal initiates a first registration message to the data management network element. The first registration message may include a second correspondence between the pairing identifier of the second terminal and the identifier of the first session management network element of the second terminal. The first registration message can be used to notify the data management network element of the information of the first session management network element of the second terminal, so that the data management network element can save the second correspondence.

[0115] Step 4: After receiving the first registration message, the data management network element saves the second corresponding relationship.

[0116] For example, the data management network element can save the second correspondence in the session of the second terminal. The data management network element can also synchronously save the second correspondence in the session information of the first terminal, so that when the first terminal subsequently comes online, the second correspondence can be directly sent to the access management network element of the first terminal (the first access management network element). At this point, the data management network element saves the second correspondence between the pairing identifier of the second terminal and the identifier of the first session management network element of the second terminal.

[0117] In order to obtain the session management network element of the second terminal from the data management network element, the first access management network element can initiate (send) a registration request message (hereinafter referred to as the second registration request message for the convenience of description) to the data management network element. The second registration request message can carry the terminal identifier of the first terminal. The second registration request message can be used to obtain the contract information of the first terminal (hereinafter referred to as the second contract information for the convenience of description), such as obtaining the contract information of the session of the first terminal.

[0118] After the data management network element receives the second registration request message, it can first perform security authentication on the first terminal, such as determining whether the terminal identification of the first terminal is included in the pre-saved security terminal list. If it is included, the first terminal can be considered to be a safe device, and the security authentication result of the first terminal is passed. Otherwise, the first terminal can be considered not to be a safe device, and the security authentication result of the first terminal is failed.

[0119] When the data management network element completes the security authentication of the first terminal and the security authentication result of the first terminal is passed, the data management network element can then determine whether it has a second correspondence between the pairing identifier of the first terminal (which can also be understood as the pairing identifier of the second terminal) and the identifier of the first session management network element stored locally, such as determining whether there is a second correspondence in the locally stored session information of the first terminal. If so, it can be considered that the second terminal has been online, and the network side (such as the second access management network element) has previously determined a session management network element for the second terminal. The data management network element can then return the second subscription information containing the second correspondence to the first access management network element. Based on the second correspondence contained in the second subscription information, the first access management network element can obtain (learn) that the session management network element previously determined by the network side for the second terminal is the first session management network element.

[0120] After learning the first session management network element previously determined by the network side for the second terminal, the first access management network element may directly determine the first session management network element as the session management network element of the first terminal.

[0121] The above-mentioned method for the first access management network element to obtain the session management network element of the second terminal is only an example. For example, the first access management network element may also send an inquiry message to any other access management network element to inquire whether the session management network element has been determined for the terminal with the pairing identifier (the second terminal). If any other access management network element has previously determined the session management network element for the terminal with the pairing identifier, then the other access management network element may send the identifier of the session management network element determined for the terminal with the pairing identifier (the second terminal) to the first access management network element, and the first access management network element may obtain the session management network element of the second terminal based on this. The embodiment of the present application does not limit the method for the first access management network element to obtain the session management network element of the second terminal.

[0122] The second method is to randomly determine a session management network element for the first terminal.

[0123] The first access management network element may randomly select a session management network element as the session management network element of the first terminal.

[0124] After the session management network element (first session management network element) of the first terminal is determined, the first access management network element may send (initiate) a session establishment request message to the first session management network element. The session establishment request message may carry the terminal identifier of the first terminal. Optionally, the session establishment request message may also carry information such as the data network name (DNN) related to the first terminal, single network slice selection assistance information (S-NSSAI), and PDU type. The session establishment request message may be used to request the establishment of a session for the first terminal.

[0125] Step 302: After receiving the session establishment request message, the first session management network element can determine, based on the session establishment request, the user plane function network element (target user plane function network element) that serves the first terminal after the session is established. When determining the target user plane function network element of the first terminal, the first session management network element can, when the pairing identifier of the first terminal is the same as the pairing identifier of the second terminal, determine the user plane function network element of the second terminal as the target user plane function network element of the first terminal, that is, the target user plane function network element of the first terminal is the same as the user plane function network element of the second terminal.

[0126] After receiving the session establishment request message sent by the first access management network element, the first session management network element may determine a target user plane function network element for the first terminal. When determining the target user plane function network element for the first terminal, in order to ensure that the user plane function network element of the first terminal and the user plane function network element of the second terminal are the same user plane function network element, that is, in order to select the first terminal and the second terminal to the same user plane function network element, the first session management network element may first determine (obtain) the user plane function network element of the second terminal.

[0127] When determining the user plane function network element of the second terminal, the first session management network element may first obtain a first correspondence relationship that can represent the correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal, thereby quickly and accurately determining the user plane function network element of the second terminal based on the pairing identifier of the second terminal and the first correspondence relationship. The first session management network element may obtain the first correspondence relationship in two ways, which are described below:

[0128] Method 1: The first session management network element obtains the first corresponding relationship stored (saved) locally.

[0129] The first session management network element has the function of storing the first correspondence. During the process of establishing a session for a second terminal that came online earlier, the first session management network element can determine the user plane function network element of the second terminal and locally store the first correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal. Therefore, when the first session management network element determines the target user plane function network element for the first terminal that came online later, it can obtain the first correspondence from its own local machine.

[0130] If the first session management network element obtains the first corresponding relationship locally, it can be considered that the session management network element of the second terminal is the same as the session management network element of the first terminal (the first session management network element), that is, the session management network element of the first terminal and the session management network element of the second terminal are both the first session management network element. The first session management network element can further select the first terminal and the second terminal to the same user plane function network element.

[0131] However, if the first session management network element does not obtain the first corresponding relationship locally, it can be considered that either the second terminal has not yet come online, and the first terminal is the first terminal to go online among the paired terminals, so the first corresponding relationship has not yet been stored, or the session management network element of the second terminal is not the first session management network element, and the session management network element of the first terminal and the session management network element of the second terminal are not the same session management network element.

[0132] When the first session management network element has the function of storing a first correspondence between a pairing identifier of a second terminal and a user plane function network element of the second terminal, and the session management network element of the first terminal and the session management network element of the second terminal need to be determined as the same session management network element (first session management network element), but the session management network element of the first terminal and the session management network element of the second terminal are not actually determined as the same session management network element, this may be because the first terminal and the second terminal have come online at the same time, resulting in the first terminal and the second terminal being regarded as the first terminal to come online, and the session management network element determined for the first terminal and the second terminal being different. (For convenience of description, this situation is referred to as a conflict between the session management network element of the first terminal and the session management network element of the second terminal.) For convenience of description, the session management network element determined for the first terminal is referred to as the first session management network element, and the session management network element determined for the second terminal is referred to as the second session management network element.

[0133] The situation where the session management network element of the first terminal and the session management network element of the second terminal are found to conflict may be discovered by the data management network element. The present application provides a method for resolving the conflict. Please refer to Figure 4, which is a flow chart of a method provided by the present application for resolving the conflict between the session management network element of the first terminal and the session management network element of the second terminal. The process mainly includes the following steps:

[0134] Step 401: The first session management network element sends a registration message (first registration message) including a correspondence between a pairing identifier of a first terminal and an identifier of the first session management network element to a data management network element.

[0135] Step 402: The second session management network element also sends a registration message (third registration message) including the correspondence between the pairing identifier of the second terminal and the identifier of the second session management network element to the data management network element.

[0136] Step 403: The data management network element identifies, based on the contents of the first registration message and the third registration message, that the pairing identifier of the first terminal is the same as the pairing identifier of the second terminal, but the first session management network element of the first terminal is different from the second session management network element of the second terminal. The data management network element may send a terminal re-online indication to the first access management network element or send a terminal re-online indication to the first session management network element. The terminal re-online indication may be used to instruct the first terminal to be put back online.

[0137] Specifically, if the data management network element recognizes that the pairing identifier of the first terminal in the first registration message is the same as the pairing identifier of the second terminal in the third registration message, but the first session management network element and the second session management network element are different, it can be considered that the network side has connected (determined) the two terminals with the same pairing identifier to different session management network elements, and a conflict occurs between the session management network elements of the first terminal and the second terminal. To resolve this conflict, the first terminal and the second terminal are connected to the same session management network element. The data management network element can send a terminal re-online indication to the access management network element of either the first terminal or the second terminal, or the data management network element can send a terminal re-online indication to the session management network element of either the first terminal or the second terminal. The terminal re-online indication can be used to instruct the corresponding terminal to go back online. Therefore, during the terminal re-online process, the terminal can be treated as the terminal that comes online later. The session management network element of the terminal that comes online earlier can be re-determined based on the session management network element of the terminal that comes online earlier, thereby connecting both terminals in the paired terminals to the same session management network element.

[0138] Among them, considering that the online time of the second terminal in the above embodiments is usually earlier than that of the first terminal, for the sake of ease of understanding, it can be considered that the data management network element sends a terminal re-online indication to the first access management network element or the first session management network element of the first terminal. The terminal re-online indication can carry the terminal identifier and pairing identifier of the first terminal. After the first access management network element or the first session management network element receives the terminal re-online indication, it can initiate an offline operation of the session of the first terminal and instruct the first terminal to go back online.

[0139] In addition, considering that when the first terminal and the second terminal are online at the same time, if a session management network element is randomly determined for the first terminal and the second terminal respectively, and the session management network element determined for the first terminal and the session management network element determined for the second terminal are exactly the same session management network element (for convenience of description, referred to as the first session management network element), the first session management network element randomly determines a user plane function network element for the first terminal and also randomly determines a user plane function network element for the second terminal. However, if the user plane function network element determined for the first terminal is different from the user plane function network element determined for the second terminal, then the first terminal and the second terminal are selected to different user plane function network elements. For convenience of description, this situation is referred to as a conflict between the user plane function network element of the first terminal and the user plane function network element of the second terminal. In order to resolve this conflict, the first terminal and the second terminal are selected to the same user plane function network element. The embodiment of the present application provides the following solution. Please refer to Figure 5, which is a flow chart of a method provided by the present application for resolving a conflict between the user plane function network element of the first terminal and the user plane function network element of the second terminal. The process mainly includes the following steps:

[0140] Step 501: The first session management network element randomly determines a first user plane function network element as the user plane function network element of a first terminal. The first session management network element randomly determines a second user plane function network element as the user plane function network element of a second terminal.

[0141] Step 502: The first session management network element recognizes that the user plane function network element determined for the first terminal (first user plane function network element) is different from the user plane function network element determined for the second terminal (second user plane function network element), and changes the user plane function network element of the first terminal to the user plane function network element of the second terminal.

[0142] Specifically, when the first session management network element identifies that the user plane function network element determined for the first terminal is different from the user plane function network element determined for the second terminal, it can be considered that the first terminal and the second terminal have been selected for different user plane function network elements, and the user plane function network element determined for the first terminal and the user plane function network element determined for the second terminal can be adjusted to the same user plane function network element. For example, the user plane function network element of the first terminal can be changed to the user plane function network element of the second terminal, that is, the user plane function network element of the first terminal and the user plane function network element of the second terminal both determine the second user plane function network element. Of course, the second user plane function network element of the second terminal can also be changed to the user plane function network element of the first terminal, that is, the user plane function network element of the first terminal and the user plane function network element of the second terminal both determine the first user plane function network element. This application does not specifically limit this.

[0143] In addition, if the first terminal and the second terminal are both selected to the same session management network element (such as the first session management network element), in order to ensure to the greatest extent possible that the two terminals with the same pairing identifier can be selected to the same user plane function network element, when the first session management network element needs to determine the user plane function network element for any terminal (such as the first terminal), it can first determine whether the terminals for which the user plane function network element currently needs to be determined include a terminal with the same pairing identifier as the terminal (such as the second terminal). If so, the two terminals with the same pairing identifier can be selected to the same user plane function network element, thereby ensuring to the greatest extent possible that the two terminals with the same pairing identifier are selected to the same user plane function network element.

[0144] Method 2: The first session management network element obtains the first corresponding relationship from the data management network element by interacting with the data management network element.

[0145] In this manner, the first session management network element may not have the function of storing (saving) the first corresponding relationship, while the data management network element has the function of storing the first corresponding relationship.

[0146] Among them, when the data management network element saves the first correspondence, it may be that the second session management network element determines the user plane function network element of the second terminal, and the second session management network element sends a second registration message to the data management network element. The second registration information contains the first correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal. When the data management network element receives the second registration message, it can store (save) the first correspondence. For example, the data management network element can store the first correspondence in the session of the second terminal. In addition, the data management network element can also synchronously save the first correspondence in the session information of the first terminal, so that when the first terminal goes online later, the first correspondence is sent to the access management network element (first access management network element) of the first terminal, so that the first access management network element can obtain the first correspondence.

[0147] Specifically, the first session management network element interacts with the data management network element to obtain the first corresponding relationship in the following manner:

[0148] The first session management network element sends a contract information acquisition message to the data management network element. The contract information acquisition message may include the terminal identifier of the first terminal. The contract information acquisition message can be used to obtain the contract information of the first terminal. After receiving the contract information acquisition message, the data management network element can query the pairing identifier that matches the first terminal based on the terminal identifier of the first terminal, then obtain (search) the first corresponding relationship locally, and include the first corresponding relationship in the first contract information and return it to the first session management network element.

[0149] In addition, when the first session management network element obtains the first corresponding relationship from the data management network element based on the second method, it can be considered that the first session management network element does not locally store the first corresponding relationship. The first session management network element needs to obtain the first corresponding relationship from the data management network element, and then determine (obtain) the user plane function network element of the second terminal based on the first corresponding relationship and the pairing identifier of the second terminal, thereby determining the user plane function network element of the second terminal as the target user plane function network element of the first terminal, thereby selecting the first terminal and the second terminal to the same user plane function network element.

[0150] Considering that if the first terminal and the second terminal go online at the same time, the first terminal and the second terminal are respectively regarded as the terminals that go online first (first terminals), and their respective user plane function network elements are randomly determined for the first terminal and the second terminal, and the user plane function network element determined by the network side (such as the first session management network element) for the first terminal is the first user plane function network element, and the user plane function network element determined by the network side (such as the second session management network element) for the second terminal is the second user plane function network element, and the first user plane function network element and the second user plane function network element are different, it can be considered that a conflict has occurred between the user plane function network element of the first terminal and the user plane function network element of the second terminal. This conflict between the user plane function network element of the first terminal and the user plane function network element of the second terminal can be discovered by the data management network element. Please refer to Figure 6, which is another method flow diagram provided by the present application for resolving the conflict between the user plane function network element of the first terminal and the user plane function network element of the second terminal. The process mainly includes the following steps:

[0151] Step 601: The first session management network element sends a registration message (referred to as a fourth registration message for ease of description) including a correspondence between a pairing identifier of a first terminal and an identifier of a first user plane function network element to a data management network element.

[0152] Step 602: The second session management network element sends a registration message (referred to as a fifth registration message for ease of description) including a correspondence between the pairing identifier of the second terminal and the identifier of the second user plane function network element to the data management network element.

[0153] Step 603: Based on the contents of the fourth registration message and the fifth registration message, the data management network element identifies that the pairing identifier of the first terminal is the same as the pairing identifier of the second terminal, but the user plane function network element of the first terminal (the first user plane function network element) is different from the user plane function network element of the second terminal (the second user plane function network element). The data management network element sends a terminal re-online indication to the first access management network element or to the first session management network element. The terminal re-online indication can be used to instruct the first terminal to be put back online.

[0154] Specifically, when the data management network element identifies that the pairing identifier of the first terminal in the fourth registration message is the same as the pairing identifier of the second terminal in the fifth registration message, but the first user plane function network element in the fourth registration message is different from the second user plane function network element in the fifth registration message, it can be considered that the network side has selected the two terminals with the same pairing identifier to different user plane function network elements. The data management network element can send a terminal re-online indication to the access management network element of any one of the first terminal and the second terminal, or the data management network element can also send a terminal re-online indication to the session management network element of any one of the first terminal and the second terminal. The terminal re-online indication can be used to instruct the corresponding terminal to be put back online, so that in the process of the terminal coming back online, the terminal can be used as the terminal that comes online later, and the user plane function network element of the terminal that comes online later can be re-determined according to the user plane function network element of the terminal that comes online first, so that the two terminals in the paired terminals are selected to the same user plane function network element.

[0155] Taking into account that the online time of the second terminal in the above embodiments is usually earlier than that of the first terminal, for the sake of ease of understanding, it can be considered that the data management network element sends a terminal re-online indication to the first access management network element or the first session management network element of the first terminal. The terminal re-online indication may carry the terminal identifier and pairing identifier of the first terminal. After the first access management network element or the first session management network element receives the terminal re-online indication, it may initiate an offline operation for the session of the first terminal and instruct the first terminal to go back online.

[0156] Because in an embodiment of the present application, the first session management network element can determine the user plane function network element previously determined by the network side for the second terminal as the target user plane function network element for the first terminal when the pairing identifier of the first terminal is the same as the pairing identifier of the second terminal, thereby achieving the purpose of selecting both terminals in the paired terminals to the same user plane function network element.

[0157] For ease of understanding, the UPF determination method provided in this application is explained below using a specific embodiment. This embodiment can be understood as determining the SMF of the first terminal based on the SMF previously determined for the second terminal. By selecting the first and second terminals to the same SMF, the SMF can select the first and second terminals to the same UPF.

[0158] Please refer to Figures 7 and 8. Figure 7 is a flow chart of a method for determining a user plane function network element of a second terminal according to an embodiment of the present application, and Figure 8 is a flow chart of a method for determining a user plane function network element of a first terminal according to an embodiment of the present application. The process of determining the user plane function network element of the second terminal in Figure 7 mainly includes the following steps:

[0159] Step 701: When a second terminal comes online, it initiates a Registration Request message. This Registration Request message can be used to request that the second terminal itself be registered with the network. The Registration Request message carries the terminal identifier of the second terminal (also referred to as the user identifier of the second terminal). Upon receiving the Registration Request message initiated by the second terminal, the wireless (base station) can randomly select an AMF (second AMF) for the second terminal and send the Registration Request message to the second AMF.

[0160] Step 702: After receiving the registration request message, the second AMF can initiate a registration request message to the UDM. This registration request message can be used to register the second AMF of the second terminal with the UDM, so that the UDM can store the correspondence between the identifiers of the second terminal and the second AMF. In addition, the registration request message can also be used to obtain the contract information of the second terminal. The registration request message carries the terminal identifier of the second terminal. The UDM performs security authentication on the second terminal. The process of performing security authentication on the second terminal is similar to the security authentication process for the first terminal in the above embodiment and is not repeated here.

[0161] Step 703: When the UDM completes the security authentication of the second terminal and the security authentication result of the second terminal is passed, the UDM can determine whether the correspondence between the pairing identifier of the second terminal and the identifier of the SMF is stored locally. At this time, the second terminal is the first terminal to go online in the paired terminals, and the UDM has not yet saved the correspondence between the pairing identifier of the second terminal and the identifier of the SMF (first SMF). The UDM can return the contract information of the second terminal to the second AMF. The contract information may include the pairing identifier of the second terminal. The contract information does not include the correspondence between the pairing identifier of the second terminal and the identifier of the SMF (first SMF).

[0162] Step 704: After the second AMF receives the subscription information of the second terminal returned by the UDM, it can be considered that the registration of the second terminal is completed, and a Registration Accept message can be returned to the second terminal. The Registration Accept message is used to respond to the registration request message initiated by the terminal.

[0163] Step 705: After receiving the registration acceptance message returned by the second AMF, the second terminal may return a registration complete message to the second AMF. The registration complete message may be used to indicate that the terminal has completed registration.

[0164] Step 706: The second terminal may initiate a session establishment request message (such as a PDU Session Establishment Request). The session establishment request message may be used to request establishment of a session (PDU session) for the second terminal. The session establishment request message may carry the terminal identifier of the second terminal. In addition, the session establishment request message may also carry information related to the second terminal, such as DNN, S-NSSAI, and PDU type.

[0165] Step 707: After receiving the session establishment request message from the second terminal, the second AMF can query whether the SMF selection subscription data (SMF Selection Subscription data) of the second terminal's pairing identifier is included in the contract information of the second terminal received from the UDM, that is, query whether the contract information of the second terminal contains the correspondence between the second terminal's pairing identifier and the identifier of the SMF (first SMF). Since the contract information of the second terminal does not contain this correspondence, it can be considered that the second terminal is the first terminal to go online among the paired terminals. The second AMF can randomly select (register) an SMF for the second terminal. For the convenience of description, the SMF selected for the second terminal is called the first SMF.

[0166] Step 708: The second AMF sends (initiates) a session establishment request (Nsmf_PDUSession_CreateSMContext Request) message to the first SMF. The session establishment request message can be used to instruct the first SMF to establish a session for the second terminal. The session establishment request message may include the terminal identifier of the second terminal. In addition, the session establishment request message may also carry information such as the DNN, S-NSSAI, and PDU type of the second terminal.

[0167] Step 709: After the first SMF receives the session establishment request message sent by the second AMF, it can interact with the UDM. For example, the first SMF sends a contract information acquisition (Nudm_SDM_Get) message to the UDM. The contract information acquisition message includes the terminal identifier of the second terminal. The contract information acquisition message can be used to obtain the contract information of the session of the second terminal.

[0168] Step 710: After receiving the contract information acquisition message, the UDM may return the contract information of the second terminal's session to the first SMF. The contract information may include the pairing identifier of the second terminal.

[0169] Step 711: After the first SMF receives the subscription information of the second terminal returned by the UDM, it may return a session establishment response (Nsmf_PDUSession_CreateSMContext Response) message to the second AMF. The session establishment response message is used to indicate that the session of the second terminal has been established.

[0170] Step 712: After the first SMF receives the contract information including the pairing identifier of the second terminal returned by the UDM, since the second terminal is the first terminal to go online in the paired terminals, the first SMF has not yet locally saved the first correspondence between the pairing identifier of the second terminal and the identifier of the UPF of the second terminal. The first SMF can randomly select a UPF as the UPF of the second terminal. At the same time, in order to register the two terminals in the paired terminals to the same UPF when the other terminal (the first terminal) in the paired terminals goes online later, the first SMF can save the first correspondence between the pairing identifier of the second terminal and the identifier of the UPF of the second terminal. That is, the first SMF can determine the UPF of the second terminal and save the first correspondence in the process of establishing a session for the second terminal. At this point, the first correspondence is saved in the first SMF.

[0171] The present application does not specifically limit the order of step 711 and step 712.

[0172] Step 713: The first SMF may send a Packet Forwarding Control Protocol (PFCP) session establishment request message to the target UPF via the N4 interface. The PFCP session establishment request message may be used to instruct the UPF to establish session resources for the second terminal. The PFCP session establishment request message may carry the terminal identifier, pairing identifier, and session group identifier of the second terminal. Similar to the pairing identifier, the session group identifier of the terminal may also be pre-assigned to the terminal by the network side, which will not be described in detail here.

[0173] Step 714: After the UPF of the second terminal receives the PFCP session establishment request message sent by the first SMF, it can establish the session resources of the second terminal. After the session resources of the second terminal are established, the UPF of the second terminal can return a PFCP session establishment response message (Session Establishment Response) to the first SMF. The PFCP session establishment response message can indicate that the session resources of the second terminal have been established. In addition, the UPF of the second terminal can record the pairing identifier of the second terminal and session information such as the session and session group identifier of the second terminal. Subsequently, the UPF can perform dual-transmission selective forwarding on the session of the two terminals (the first terminal and the second terminal) in the pairing identifier based on the recorded pairing identifier and session information.

[0174] Step 715: The first SMF may return a transfer message (eg, Namf_Communication_N1N2_message_transfer) to the second AMF. The transfer message may be used to indicate that the session of the second terminal has been established.

[0175] Step 716: After the second AMF receives the transmission message sent by the first SMF, it can return a session establishment acceptance message (such as a PDU session establishment accept message) to the second terminal. The session establishment acceptance message is used to inform the terminal that the session has been established.

[0176] Step 717: The second AMF sends a session modification request message (such as Nsmf_PDUSession_UpdateSMContext Request message) to the first SMF. The session modification request message can instruct the first SMF to update the base station side resources to the UPF.

[0177] Step 718: The first SMF sends a session modification request message to the UPF of the second terminal. The session modification request message can be used to indicate the update of the tunnel information allocated by the UPF on the base station side.

[0178] Step 719: After the UPF of the second terminal updates the tunnel information allocated by the UPF on the base station side, it can return a session modification response message to the first SMF. The session modification response message is used to indicate that the tunnel information allocated by the UPF on the base station side has been updated.

[0179] Step 720: After receiving the session modification response message returned by the UPF of the second terminal, the first SMF initiates a registration message (such as Nudm_UECM_Registration message, referred to as the first registration message for the convenience of description) to the UDM. The first registration message may include the correspondence between the pairing identifier of the second terminal and the identifier of the first SMF (the second correspondence). The first registration message can be used to notify the UDM of the information of the first SMF of the second terminal so that the UDM can save the second correspondence. In addition, the first registration message may also include the user permanent identifier (SUPI), DNN, S-NSSAI, PDU session identifier (PDU session id), etc. of the second terminal.

[0180] Step 721: After receiving the first registration message, the UDM may save the second corresponding relationship.

[0181] For example, the UDM can save the second correspondence to the session of the second terminal. In addition, the UDM can also save the second correspondence to the session information of the first terminal, so that when the first terminal goes online later, the second correspondence can be sent to the AMF of the first terminal (the first AMF), so that the first AMF can determine the first SMF as the SMF of the first terminal, so that the SMF of the first terminal and the SMF of the second terminal can be selected as the same SMF, thereby ensuring that the first SMF can select the UPF of the first terminal and the UPF of the second terminal as the same UPF. At this point, the second correspondence is saved in the UDM.

[0182] Step 722: The first SMF may return a session update response message (such as an Nsmf_PDUSession_UpdateSMContext Response message) to the second AMF. The session update response message may be used to indicate that the reference side resources have been updated.

[0183] This application does not specifically limit the order between step 722 and step 720. For example, step 720-step 721 can be executed first, and then step 722 can be executed, or step 722 can be executed first, and then step 720-step 721 can be executed, or step 720 and step 722 can be executed simultaneously in parallel.

[0184] The process of determining the user plane function network element of the first terminal in FIG8 mainly includes the following steps:

[0185] Step 801: Similar to step 701, when a first terminal comes online, the first terminal initiates a registration request message (first registration request message). This registration request message can be used to request that the first terminal itself be registered with the network. The registration request message carries the terminal identifier of the first terminal. When the wireless (base station) receives the registration request message initiated by the first terminal, it can randomly select an AMF (first AMF) for the first terminal and send the registration request message to the first AMF.

[0186] Step 802: Similar to step 702, after receiving the registration request message, the first AMF can initiate a registration request message (a second registration request message) to the UDM. This registration request message can be used to register the first AMF of the first terminal with the UDM, so that the UDM can store the correspondence between the identifiers of the first terminal and the first AMF. In addition, the registration request message can also be used to obtain the contract information of the first terminal. The registration request message carries the terminal identifier of the first terminal and can be used to obtain the contract information of the first terminal. The UDM performs security authentication on the first terminal.

[0187] Step 803: When the UDM completes the security authentication of the first terminal and the security authentication result of the first terminal is passed, the UDM can determine whether it has locally saved the correspondence between the pairing identifier of the first terminal and the identifier of the SMF. Since the second terminal is already online, the second correspondence between the pairing identifier of the second terminal (that is, the pairing identifier of the first terminal) and the identifier of the first SMF saved by the UDM, the UDM can include the second correspondence in the contract information of the first terminal (the second contract information) and return it to the first AMF. Based on this, the first AMF can obtain the SMF of the second terminal based on the second correspondence and the pairing identifier of the second terminal.

[0188] Step 804: Similar to step 704, after the first AMF receives the subscription information of the first terminal returned by the UDM, it can be considered that the registration of the first terminal is completed, and a registration acceptance message can be returned to the first terminal. The registration acceptance message is used to respond to the registration request message initiated by the terminal.

[0189] Step 805: Similar to step 705, after the first terminal receives the registration acceptance message returned by the first AMF, it can return a registration completion message to the first AMF. The registration completion message can be used to indicate that the terminal has completed registration.

[0190] Step 806: Similar to step 706, the first terminal can initiate a session establishment request message, which can be used to request to establish a session (PDU session) for the first terminal. The session establishment request message can carry the terminal identifier of the first terminal. In addition, the session establishment request message can also carry DNN, S-NSSAI, PDU type and other information related to the first terminal.

[0191] Step 807: After the first AMF receives the session establishment request message from the first terminal, it can query whether the contract information (second contract information) of the first terminal received from the UDM contains the selected subscription data of the SMF of the pairing identifier of the first terminal, that is, query whether the contract information (second contract information) of the first terminal contains the second correspondence between the pairing identifier of the second terminal and the identifier of the SMF (first SMF). When the first AMF finds that the contract information of the first terminal contains the second correspondence, the first AMF can know that the SMF of the second terminal is the first SMF based on the second correspondence and the pairing identifier of the second terminal, and therefore can select the first SMF as the SMF of the first terminal.

[0192] Step 808: Similar to step 708, the first AMF sends (initiates) a session establishment request message to the first SMF. The session establishment request message may include the terminal identifier of the first terminal. In addition, the session establishment request message may also carry the DNN, S-NSSAI, PDU type and other information of the first terminal. The session establishment request message is used to instruct the first SMF to establish a session for the first terminal.

[0193] Step 809: Similar to step 709, after the first SMF receives the session establishment request message sent by the first AMF, it can interact with the UDM. For example, the first SMF sends a contract information acquisition message to the UDM. The contract information acquisition message includes the terminal identifier of the first terminal. The contract information acquisition message can be used to obtain the contract information of the session of the first terminal.

[0194] Step 810: Similar to step 710, after receiving the contract information acquisition message, the UDM may return the contract information (first contract information) of the session of the first terminal to the first SMF. The contract information may include the pairing identifier of the first terminal.

[0195] Step 811: Similar to step 711, after the first SMF receives the contract information of the first terminal returned by the UDM, it can return a session establishment response message to the first AMF. The session establishment response message is used to indicate that the session of the first terminal has been established.

[0196] Step 812: After the first SMF receives the signing information including the pairing identifier of the first terminal returned by the UDM, it can check whether the correspondence between the pairing identifier of the second terminal and the identifier of the UPF of the second terminal is stored locally. Since the first SMF has previously determined the UPF for the second terminal, the first SMF locally stores the correspondence between the pairing identifier of the second terminal and the identifier of the UPF of the second terminal (first correspondence). The first SMF can obtain (learn) the UPF of the second terminal based on the locally stored first correspondence and the pairing identifier of the second terminal, and can directly determine the UPF of the second terminal as the target UPF of the first terminal.

[0197] The present application does not specifically limit the order of step 811 and step 812.

[0198] Step 813: Similar to step 713, the first SMF may send a PFCP session establishment request message to the UPF. The PFCP session establishment request message may carry the terminal identifier, pairing identifier, and session group identifier of the first terminal.

[0199] Step 814: Similar to step 714, after the target UPF receives the PFCP session establishment request message sent by the first SMF, it can establish the session resources of the first terminal. After the session resources of the first terminal are established, the target UPF can return a PFCP session establishment response message to the first SMF. The PFCP session establishment response message can indicate that the session resources of the first terminal have been established. In addition, the target UPF can record the pairing identifier of the first terminal and the session information of the first terminal, such as the session and session group identifier. Subsequently, the target UPF can perform dual-send selective forwarding on the session of the two terminals (the first terminal and the second terminal) in the pairing identifier based on the recorded pairing identifier and session information, which will not be repeated here.

[0200] Step 815: Similar to step 715, the first SMF may return a transfer message (eg, Namf_Communication_N1N2_message_transfer) to the first AMF. The transfer message may be used to indicate that the session of the first terminal has been established.

[0201] Step 816: Similar to step 716, after receiving the transmission message, the first AMF may return a session establishment acceptance message to the first terminal. The session establishment acceptance message is used to inform the terminal that the session has been established.

[0202] Step 817: Similar to step 717, the first AMF may send a session modification request message to the first SMF, which may instruct the first SMF to update the base station side resources to the target UPF.

[0203] Step 818: Similar to step 718, the first SMF sends a session modification request message to the target UPF. The session modification request message can be used to indicate the update of the tunnel information allocated by the UPF on the base station side.

[0204] Step 819: Similar to step 719, after the target UPF updates the tunnel information allocated by the UPF on the base station side, it can return a session modification response message to the first SMF. The session modification response message is used to indicate that the tunnel information allocated by the UPF on the base station side has been updated.

[0205] Step 820: Similar to step 720, after the first SMF receives the session modification response message returned by the target UPF, it initiates a registration message to the UDM. The registration message may include the correspondence between the pairing identifier of the first terminal and the identifier of the first SMF. The registration message can be used to notify the UDM of the information of the first SMF of the first terminal, so that the UDM can save the correspondence between the pairing identifier of the first terminal and the identifier of the first SMF. In addition, the registration message may also include the SUPI, DNN, S-NSSAI, PDU session id, etc. of the first terminal. Since the second terminal goes online earlier than the first terminal, the UDM has already saved the second correspondence when the second terminal goes online (in step 720). Therefore, step 820 is an optional step.

[0206] Step 821: Similar to step 722, the first SMF may return a session update response message to the first AMF.

[0207] At this point, the two paired terminals, the first terminal and the second terminal, can subsequently implement processes such as dual-transmission selective reception and forwarding based on the same UPF.

[0208] If the first SMF has the function of saving the first correspondence between the pairing identifier of the second terminal and the identifier of the UPF of the second terminal, and in step 812, if the first SMF does not obtain the first correspondence locally, it can be considered that either the second terminal has not yet come online, and the first terminal is the first terminal to come online in the paired terminals, so the first correspondence has not yet been saved, or it is because the first terminal and the second terminal may have come online at the same time, resulting in the first terminal and the second terminal being regarded as the first terminal to come online (the first terminal), and their respective SMFs are randomly determined for the first terminal and the second terminal, respectively. The SMF of the second terminal is not the first SMF, and the SMF of the first terminal and the SMF of the second terminal are not the same SMF, and a conflict occurs between the SMF of the first terminal and the SMF of the second terminal. Please refer to Figure 9, which is a flow chart of a method provided by the present application for resolving the conflict between the SMF of the first terminal and the SMF of the second terminal. The process mainly includes the following steps:

[0209] Step 900: Step 900 includes the online process of the second terminal described in steps 701 to 720 in Figure 7. Unlike Figure 7, the online process of the second terminal in Figure 9 can replace the first SMF in steps 701 to 720 in Figure 7 with the second SMF, and the first registration message with the third registration message. In addition, step 900 also includes the online process of the first terminal. The online process of the first terminal can refer to steps 701 to 720 in Figure 7. Unlike Figure 7, the online process of the first terminal in step 900 replaces the second terminal in steps 701 to 720 in Figure 7 with the first terminal, and the second AMF with the first AMF.

[0210] Step 901: When the UDM recognizes that the pairing identifier of the first terminal in the first registration message is the same as the pairing identifier of the second terminal in the third registration message, but the first SMF is different from the second SMF, the UDM sends a terminal re-online indication to the first AMF or to the first SMF, and the terminal re-online indication carries the terminal identifier and pairing identifier of the first terminal.

[0211] Step 902: After receiving the terminal back-online indication, the first AMF or the first SMF may initiate a session offline operation for the first terminal and instruct the first terminal to come back online. When the first terminal comes back online, the process of determining the UPF for the first terminal may be repeated according to the process in Figure 8. That is, the process of determining the UPF for the second terminal may be repeated according to the process in Figure 7, and the process of determining the UPF for the first terminal may be repeated according to the process in Figure 8, thereby ensuring that the same UPF is selected for the first and second terminals. This will not be repeated here.

[0212] For ease of understanding, the UPF determination method provided in this application is explained below using a specific embodiment. This embodiment can be understood as follows: even if the first terminal and the second terminal are not selected to the same SMF, the network side can also determine the UPF of the first terminal based on the UPF previously determined for the second terminal, thereby achieving the selection of the first terminal and the second terminal to the same UPF.

[0213] Please refer to Figures 10 and 11. Figure 10 is a flowchart of another method for determining the UPF of a second terminal provided by this application, and Figure 11 is a flowchart of another method for determining the UPF of a first terminal provided by this application. The process of determining the UPF of the second terminal in Figure 10 mainly includes the following steps:

[0214] Step 1001 - Step 1002: Please refer to Step 701 - Step 702 in Figure 7 above, and no further details will be given here.

[0215] Step 1003: When the UDM completes the security authentication of the second terminal and the security authentication result of the second terminal is passed, the UDM may return the contract information of the second terminal to the second AMF. The contract information may not include the pairing identifier of the second terminal.

[0216] Step 1004 - Step 1006: Please refer to Step 704 - Step 706 in FIG. 7 , which will not be described in detail here.

[0217] Step 1007-Step 1011: Similar to Step 707-711 in Figure 7, except that the first SMF in Step 707-711 needs to be replaced by the second SMF, which will not be repeated here.

[0218] Step 1012: is similar to step 712 in FIG. 7 , except that the first SMF in step 712 needs to be replaced by the second SMF, and the second SMF in step 1012 does not save the first correspondence, while the first SMF in step 712 saves the first correspondence.

[0219] Step 1013 to step 1019 are similar to step 713 to step 719 in FIG. 7 , except that the first SMF in step 713 to step 719 needs to be replaced by the second SMF.

[0220] Step 1020: The second SMF initiates a registration message to the UDM. The registration message may include the first correspondence between the pairing identifier of the second terminal and the identifier of the UPF of the second terminal. The registration message may be used to notify the UDM of the information of the UPF of the second terminal so that the UDM can save the first correspondence. In addition, the registration message may also include the SUPI, DNN, S-NSSAI, PDU session ID, etc. of the second terminal.

[0221] Step 1021: After receiving the registration message, the UDM saves the first correspondence.

[0222] For example, the UDM can save the first correspondence in the session of the second terminal. In addition, the UDM can also save the first correspondence in the session information of the first terminal, so that when the first terminal subsequently comes online, the first correspondence can be sent to the SMF of the first terminal (the first SMF), so that the first SMF can know the UPF of the second terminal and then select the UPF of the first terminal and the UPF of the second terminal as the same UPF.

[0223] Step 1022: is similar to step 722 in FIG. 7 , except that the first SMF in step 722 needs to be replaced by the second SMF.

[0224] The process of determining the user plane function network element of the first terminal in FIG11 mainly includes the following steps:

[0225] Step 1101 - Step 1102: Please refer to Step 801 - Step 802 in Figure 8 above, and no further details will be given here.

[0226] Step 1103: is similar to step 1003 in FIG10 , except that the second terminal in step 1003 needs to be replaced by the first terminal, which will not be described again here.

[0227] Step 1104 - Step 1106: Please refer to Step 804 - Step 806 in FIG. 8 , which will not be described in detail here.

[0228] Step 1107: The first AMF randomly selects an SMF for the first terminal. For the convenience of description, the SMF selected for the first terminal is referred to as the first SMF.

[0229] Step 1108 - Step 1111: Please refer to Step 808 - Step 811 in the aforementioned FIG8 , which will not be repeated here.

[0230] Step 1112: The first SMF interacts with the UDM, and the first SMF obtains a first corresponding relationship from the UDM.

[0231] Step 1113 - Step 1119: Please refer to Step 813 - Step 819 in FIG. 8 , which will not be repeated here.

[0232] Step 1120: is similar to step 1020 in FIG10 , except that the second terminal in step 1020 needs to be replaced by the first terminal, and the second SMF needs to be replaced by the first SMF, which will not be repeated here.

[0233] In addition, since the second terminal goes online earlier than the first terminal, the UDM has already saved the first corresponding relationship when the second terminal goes online (in step 1020), so step 1120 is an optional step.

[0234] Step 1121: Please refer to step 821 in Figure 8 above, which will not be repeated here.

[0235] Considering that if the first terminal and the second terminal go online at the same time, the first terminal and the second terminal are respectively regarded as the terminals that go online first (first terminal), and their respective UPFs are randomly determined for the first terminal and the second terminal, and the UPF determined by the network side (such as the first SMF) for the first terminal is the first UPF, and the UPF determined by the network side (such as the second SMF) for the second terminal is the second UPF, when the first UPF and the second UPF are different, it can be considered that a conflict has occurred between the UPF of the first terminal and the UPF of the second terminal. Please refer to Figure 12, which is a flow chart of a method provided by the present application for resolving the conflict between the UPF of the first terminal and the UPF of the second terminal. The process mainly includes the following steps:

[0236] Step 1200: Step 1200 includes the online process of the second terminal described in steps 1001 to 1020 in Figure 10. Unlike Figure 10, in the online process of the second terminal in Figure 12, the UPF in steps 1001 to 1020 in Figure 10 may be replaced with the second UPF, and the registration message in step 1020 may be replaced with the fifth registration message. Furthermore, step 900 also includes the online process of the first terminal. The online process of the first terminal may refer to steps 1001 to 1020 in Figure 10. However, in the online process of the first terminal in step 1200, the second terminal in steps 1001 to 1020 in Figure 10 may be replaced with the first terminal, the second AMF may be replaced with the first AMF, the target UPF may be replaced with the first UPF, and the registration message in step 1020 may be replaced with the fourth registration message.

[0237] Step 1201: When the UDM recognizes that the pairing identifier of the first terminal in the fourth registration message is the same as the pairing identifier of the second terminal in the fifth registration message, but the first UPF in the fourth registration message is different from the second UPF in the fifth registration message, the UDM sends a terminal re-online indication to the first AMF or to the first SMF, and the terminal re-online indication carries the terminal identifier and pairing identifier of the first terminal.

[0238] Step 1202: After receiving the terminal back-online indication, the first AMF or the first SMF may initiate a session offline operation for the first terminal and instruct the first terminal to come back online. When the first terminal comes back online, the process of determining the UPF for the first terminal may be repeated according to the process in Figure 11. That is, the process of determining the UPF for the second terminal may be repeated according to the process in Figure 10, and the process of determining the UPF for the first terminal may be repeated according to the process in Figure 11, thereby ensuring that the same UPF is selected for the first and second terminals. This will not be repeated here.

[0239] The following describes how the first terminal can be put back online after the first AMF and the first SMF receive the terminal back online instruction. The embodiment of the present application provides three ways to make the first terminal offline and back online.

[0240] The first method of making the first terminal offline and back online: UDM sends a terminal back online instruction to the first SMF.

[0241] Referring to Figure 13, the process includes the following steps:

[0242] Step 1301, UDM sends a terminal re-online indication to the first SMF, and the terminal re-online indication includes a session release request, which is used to instruct the first SMF to release the session of the first terminal. The terminal re-online indication may carry the terminal identifier, pairing identifier, etc. of the first terminal.

[0243] Step 1302: The first SMF selects the session of the first terminal based on the correspondence between the session and the terminal identifier and the pairing identifier, and sends (initiates) a session release request (Session Release Request) message to the first UPF corresponding to the first terminal determined previously. The session release request message is used to indicate that the session of the first terminal is to be released.

[0244] Step 1303: After the first UPF receives the session release request message, it can perform the session release process for the first terminal. After releasing the session, the first UPF returns a session release response (Session Release Response) message to the first SMF. The session release response message is used to indicate that the session of the first terminal has been released.

[0245] Step 1304: The first SMF sends a transfer message (e.g., Namf_Communication_N1N2_message_transfer) to the first AMF. The transfer message is used to indicate the deletion (release) of the session of the first terminal. In addition, the transfer message may also carry a reconnection instruction (Reattach indication), which can be used to instruct the first terminal to re-initiate a session establishment request message after releasing the corresponding session.

[0246] Step 1305: After receiving the transmission message, the first AMF initiates a session release request message (such as PDU session Release Request) to the first terminal. The session release request message may carry the above-mentioned reconnection instruction. The session release request is used to instruct the terminal to release the session. The reconnection instruction is used to instruct the first terminal to re-initiate a session establishment request message after releasing the corresponding session.

[0247] Step 1306: After receiving the session release request message, the first terminal can delete the corresponding session and return a session release confirmation message (such as a PDU session Release Ack message) to the first AMF through the base station. The session release confirmation message can be used to indicate (characterize) that the corresponding session has been deleted.

[0248] Step 1307: The first terminal re-initiates a session establishment request message according to the reconnection instruction carried in the session release request message. At this point, the first terminal can serve as the terminal that came online later in the paired terminal and go back online through the relevant steps in Figure 8 (e.g., steps 806-821), ensuring that the same UPF is selected as the second terminal. For example, the process of determining the UPF for the second terminal is performed according to the process in Figure 7, and the process of determining the UPF for the first terminal is performed according to the process in Figure 8, thereby ensuring that the first terminal and the second terminal are selected to the same UPF. This will not be repeated here.

[0249] The second way to make the first terminal offline and back online: UDM sends a terminal back online indication to the first AMF.

[0250] Referring to Figure 14, the process includes the following steps:

[0251] Step 1401: UDM sends a terminal re-online indication to the first AMF. The terminal re-online indication may be a deregistration notification (such as DeregistrationNotification). The deregistration reason (deregReason) in the deregistration notification may be, for example, re-registration (such as REREGISTRATION_REQUIRED). The deregistration notification may be used to instruct the first AMF to re-initiate the registration (registration) process of the terminal.

[0252] Step 1402: The first AMF initiates a deregistration request message to the first terminal based on the deregistration notification received from the UDM. The deregistration request message may carry a deregistration reason, such as reregistration (e.g., REREGISTRATION_REQUIRED).

[0253] Step 1403: The first AMF sends a resource deletion indication to the first SMF, which can be used to instruct the first SMF to delete resources such as the session corresponding to the first terminal.

[0254] Step 1404: The first terminal sends a Deregister Accept message to the first AMF. The Deregister Accept message is used to indicate that the first terminal has completed the deregistration process.

[0255] Step 1405: The first terminal re-initiates a registration request message. At this point, the first terminal can be the terminal that goes online later in the paired terminal, and can go online again through the relevant steps in Figure 8 (such as steps 801 to 821) or through the relevant steps in Figure 11 (such as steps 1101 to 1121) to achieve selection of the same UPF as the second terminal. For example, the process of determining the UPF for the second terminal is performed according to the process in Figure 7, and the process of determining the UPF for the first terminal is performed according to the process in Figure 8, thereby ensuring that the first terminal and the second terminal are selected to the same UPF. Alternatively, the process of determining the UPF for the second terminal can be performed according to the process in Figure 10, and the process of determining the UPF for the first terminal can be performed according to the process in Figure 11, thereby ensuring that the first terminal and the second terminal are selected to the same UPF. This will not be repeated here.

[0256] The third method for taking the first terminal offline and back online is similar to the second method in that the UDM sends a terminal back online instruction to the first AMF. The difference is that:

[0257] Referring to Figure 15, the process includes the following steps:

[0258] Step 1501: The UDM sends a terminal re-online indication to the first AMF. The terminal re-online indication may be a dual-send selective reception repair (Restoration) request message. The dual-send selective reception repair request message carries the pairing identifier of the first terminal and the terminal identifier of the first terminal.

[0259] Step 1502: After the first AMF receives the dual-transmission selective reception repair request message initiated by the UDM, the first AMF sends a session release request (Namf_PDUSession_ReleaseSMContext Request) message to the first SMF. The session release request message is used to instruct the SMF to release the terminal session. The session release request message carries the pairing identifier of the first terminal and the terminal identifier of the first terminal.

[0260] Step 1503: After the first SMF receives the session release request message (also called the session deletion request message), it can select the session of the first terminal based on the pairing identifier and terminal identifier of the first terminal, and initiate a session release request (Session Release Request) message to the first UPF. The session release request message is used to instruct the UPF to release the session of the first terminal.

[0261] Step 1504: After receiving the session release request message, the first UPF releases the session of the first terminal and returns a session release response (Session Release Response) message to the first SMF. The session release response message is used to indicate that the session of the first terminal has been released.

[0262] Step 1505: The first SMF returns a session release response message (such as Namf_PDUSession_ReleaseSMContext Response message) to the first AMF. The session release response message is used to indicate that the session of the first terminal has been released.

[0263] Step 1506: The first SMF sends a transfer message (e.g., Namf_Communication_N1N2_message_transfer) to the first AMF. The transfer message can be used to instruct the first terminal to delete (release) the session. The transfer message can carry a reconnection instruction (Reattach indication), which can be used to instruct the first terminal to release the corresponding session and then re-initiate session establishment.

[0264] Step 1507: The first AMF sends a session release request message (such as a PDU session Release Request message) to the first terminal. The session release request message may carry the above-mentioned reconnection instruction. The session release request is used to instruct the terminal to release the session. The reconnection instruction is used to instruct the first terminal to re-initiate a session establishment request message after releasing the corresponding session.

[0265] Step 1508: After receiving the session release request message, the first terminal can delete the corresponding session and return a session release confirmation message (such as a PDU session Release Ack message) to the first AMF through the base station. The session release confirmation message can be used to indicate (characterize) that the corresponding session has been deleted.

[0266] Step 1509: The first terminal re-initiates a registration request message according to the reconnection instruction carried in the session release request message. At this point, the first terminal can be the terminal that goes online later in the paired terminal, and can go online again through the relevant steps in Figure 8 (such as steps 801 to 821) or through the relevant steps in Figure 11 (such as steps 1101 to 1121), so as to be selected to the same UPF as the second terminal. For example, the process of determining the UPF for the second terminal is performed according to the process in Figure 7, and the process of determining the UPF for the first terminal is performed according to the process in Figure 8, so as to ensure that the first terminal and the second terminal are selected to the same UPF. Alternatively, the process of determining the UPF for the second terminal can be performed according to the process in Figure 10, and the process of determining the UPF for the first terminal can be performed according to the process in Figure 11, so as to ensure that the first terminal and the second terminal are selected to the same UPF. No further details will be given here.

[0267] It is understandable that, in order to implement the functions in the above embodiments, the terminal equipment, the control plane network element, and the data service network element include hardware structures and / or software modules corresponding to the execution of each function. It should be readily apparent to those skilled in the art that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or in a manner driven by computer software depends on the specific application scenario and design constraints of the technical solution.

[0268] Figures 16 and 17 are schematic diagrams of possible communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the session management network element, access management network element, and data management network element in the method embodiments shown in any of Figures 3 to 15 above, thereby also achieving the beneficial effects of the above method embodiments.

[0269] As shown in Figure 16, the communication device 1600 includes a processing unit 1610 and a transceiver unit 1620. For example, the communication device 1600 is used to implement the functions of the first session management network element or the first access management network element in the method embodiment shown in Figure 3 above. For another example, the communication device 600 is used to implement the functions of the second terminal, the second AMF, the UDM, the first SMF, and the UPF in the method embodiment shown in Figure 7 above. The transceiver unit 1620 can execute the receiving and sending actions performed by each network element / device in the above method embodiment. The processing module 1610 can execute other actions, except for the sending and receiving actions, among the actions performed by each network element / device in the above method embodiment.

[0270] Exemplarily, when the communication device 1600 is used to implement the function of the first session management network element in the method embodiment shown in Figure 3: the transceiver unit 1620 is used to receive a session establishment request message; the processing unit 1610 is used to determine the target user plane function network element for the first terminal based on the session establishment request message.

[0271] A more detailed description of the processing unit 1610 and the transceiver unit 1620 can be directly obtained by referring to the relevant description in the method embodiment shown in any of Figures 3 to 15, and will not be repeated here.

[0272] As shown in Figure 17, communication device 1700 includes a processor 1710 and an interface circuit 1720. Processor 1710 and interface circuit 1720 are coupled to each other. It is understood that interface circuit 1720 can be a transceiver or an input / output interface. Optionally, communication device 1700 may also include a memory 1730 for storing instructions executed by processor 1710, input data required by processor 1710 to execute instructions, or data generated by processor 1710 after executing instructions.

[0273] When the communication device 1700 is used to implement the method shown in any of Figures 3 to 15, the processor 1710 is used to implement the functions of the above-mentioned processing unit 1610, and the interface circuit 1720 is used to implement the functions of the above-mentioned transceiver unit 1620.

[0274] When the communication device is a chip used in the first session management network element, the chip implements the functions of the first session management network element in the above method embodiment. The chip receives information from other modules in the first session management network element; or the chip sends information to other modules in the first session management network element.

[0275] When the communication device is a module applied to the first terminal, the module implements the functions of the first terminal in the above method embodiment. The module receives information from other modules in the first terminal; alternatively, the module sends information to other modules. The module can be the baseband chip of the first terminal, or it can be a DU or other module. The DU can be a DU in an open radio access network (O-RAN) architecture.

[0276] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0277] This application provides another example of a communication device, which includes at least one processor and at least one memory, the at least one processor and the at least one memory being coupled together, the at least one memory being used to store instructions. When the instructions are executed by the at least one processor, the communication device performs the method in the above-described embodiment. Taking a communication device including a processor and a memory as an example, as shown in FIG17 , a communication device 1700 includes a processor 1710 and a memory 1730. The processor 1710 and the memory 1730 are coupled together, and the memory 1730 stores instructions. When the instructions stored in the memory 1730 are executed by the processor 1710, the communication device 1700 performs the method performed by the terminal device or network device in the above-described embodiment.

[0278] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in a network device or a terminal. The processor and storage medium can also exist in a network device or a terminal as discrete components.

[0279] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0280] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0281] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship; in the formula of this application, the character " / " indicates that the previous and next associated objects are in a "division" relationship. "Including at least one of A, B and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0282] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

Claims

1. A method for determining a user plane functional network element, characterized in that: Applied to a first session management network element, including: receiving a session establishment request message sent by a first access management network element, where the session establishment request message is used to request establishment of a session for the first terminal; Determine a target user plane function network element for the first terminal according to the session establishment request message, where the target user plane function network element is used to serve the first terminal after the session is established; the target user plane function network element is the same as the user plane function network element of the second terminal, and the pairing identifiers of the first terminal and the second terminal are the same.

2. The method according to claim 1, wherein The target user plane function network element is determined based on the pairing identifier of the second terminal and a pre-acquired first correspondence relationship, where the first correspondence relationship is used to represent the correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal.

3. The method according to claim 2, wherein The first corresponding relationship is stored in the first session management network element.

4. The method according to claim 2, wherein Also includes: Sending a contract information acquisition message to a data management network element, where the contract information acquisition message is used to acquire first contract information of the first terminal; Receive the first contract information of the first terminal returned by the data management network element, where the first contract information includes the first corresponding relationship.

5. The method according to claim 3, wherein Also includes: In the process of establishing a session for the second terminal, a user plane function network element of the second terminal is determined, and a first correspondence between the pairing identifier of the second terminal and the identifier of the user plane function network element of the second terminal is saved.

6. The method according to claim 5, wherein After determining the user plane function network element of the second terminal, the method further includes: A first registration message is sent to the data management network element, where the first registration message includes a second correspondence between the pairing identifier of the second terminal and the identifier of the first session management network element.

7. A method for determining a user plane functional network element, characterized in that: Applicable to the first access management network element, including: receiving a first registration request message from a first terminal; A session establishment request message is sent to a first session management network element, where the session establishment request message is used to request establishment of a session for the first terminal. The first session management network element is the same as the session management network element of the second terminal, and the pairing identifiers of the first terminal and the second terminal are the same.

8. The method according to claim 7, wherein Also includes: Sending a second registration request message to the data management network element, where the second registration request message is used to obtain second subscription information of the first terminal; receiving second subscription information of the first terminal returned by the data management network element, where the second subscription information includes a second correspondence between the pairing identifier of the second terminal and the identifier of the first session management network element; The first session management network element is determined based on the pairing identifier of the second terminal and the second corresponding relationship.

9. A method for determining a user plane functional network element, characterized in that: Applied to data management network elements, including: A terminal re-online indication is sent to the first access management network element or to the first session management network element, where the terminal re-online indication is used to instruct the first terminal to be put back online; wherein, the first access management network element is the access management network element of the first terminal, and the first session management network element is the session management network element of the first terminal; the pairing identifier of the first terminal is the same as the pairing identifier of the second terminal, the first session management network element of the first terminal is different from the second session management network element of the second terminal, or the user plane function network element of the first terminal is different from the user plane function network element of the second terminal.

10. The method according to claim 9, wherein The terminal back online indication carries the terminal identifier of the first terminal and the pairing identifier of the first terminal.

11. A method for determining a user plane function network element, characterized in that: Applied to a first session management network element, including: When the user plane function network element of the first terminal is different from the user plane function network element of the second terminal and the pairing identifier of the first terminal is the same as the pairing identifier of the second terminal, the user plane function network element of the first terminal is changed to the user plane function network element of the second terminal.

12. A communication device, characterized in that: The method comprises a unit or module for executing the method according to any one of claims 1 to 6, or a unit or module for executing the method according to any one of claims 7 to 8, or a unit or module for executing the method according to any one of claims 9 to 10, or a unit or module for executing the method according to claim 11.

13. A communication device, characterized in that: include: One or more processors, configured to execute the method according to any one of claims 1 to 6, or the method according to any one of claims 7 to 8, or the method according to any one of claims 9 to 10, or the method according to claim 11.

14. A communication system, characterized in that: The communication system includes: a first session management network element for executing the method according to any one of claims 1 to 6, and a first access management network element for executing the method according to claim 7 or 8.

15. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program or instructions. When the computer program or instructions are executed by the communication device, the method according to any one of claims 1 to 6 is implemented, or the method according to any one of claims 7 to 8 is implemented, or the method according to any one of claims 9 to 10 is implemented, or the method according to claim 11 is implemented.

16. A chip system, characterized in that: include: a memory for storing computer programs; a processor; When the processor calls and runs the computer program from the memory, the communication device equipped with the chip system executes the method as described in any one of claims 1 to 6, or executes the method as described in any one of claims 7 to 8, or executes the method as described in any one of claims 9 to 10, or executes the method as described in claim 11.

17. A computer program product, characterized in that When the computer program product is called by a computer, the computer executes the method according to any one of claims 1 to 6, or the method according to any one of claims 7 to 8, or the method according to any one of claims 9 to 10, or the method according to claim 11.

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