Communication method and apparatus

Abstract

Embodiments of the present application relate to the technical field of communications, and provide a communication method and apparatus. The method comprises: a network exposure function network element acquires the correspondence between a first identifier of a terminal device and the identifier of subscription data of the terminal device, and then sends a first request message to a first network element, wherein the first request message is used for subscribing to a session-related event of first subscription data; and upon reception of first information from the first network element, the network exposure function network element sends a second request message to a second network element, wherein the first information is used for indicating that a switching event has occurred on the terminal device, and the second request message is used for subscribing to a session-related event of second subscription data. In this way, after the network exposure function network element interacts with an application function network element, the application function network element can synchronously switch a subscription event when session switching occurs on the terminal device, so as to obtain a correct event.

Description

A communication method and apparatus

[0001] This application claims priority to Chinese Patent Application No. 202411219444.4, filed with the State Intellectual Property Office of China on August 30, 2024, entitled "A Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0003] In the field of telecommunications, a dual-connectivity device comprises two independent user equipment (UEs). The subscription data of each UE belongs to the same operator and is associated with it. The dual-connectivity device can be a single terminal or two independent terminals. For example, in the case of a single-terminal dual-connectivity device, only one subscription data can be transmitted at a time; in the case of two independent terminals, both terminals can transmit subscription data simultaneously. Because a dual-connectivity device includes two UEs, traffic switching is possible. For a single-terminal dual-connectivity device, since only one subscription data can be transmitted at a time, traffic switching occurs at the UE level; for a dual-connectivity device with two independent terminals, traffic switching occurs at the service level.

[0004] Currently, application functions (AFs) typically map terminal-related events based on the terminal's address information, obtain the terminal's identifier, and then subscribe to the corresponding events. However, for dual-connected devices, if a session switch occurs—that is, the session changes from one subscription data to another—the AF will still store the mapping relationship where the dual-connected device's address information maps to the previous subscription data, since the dual-connected device's address information remains unchanged. But the actual subscription data of the dual-connected device's session has changed. In this scenario, the AF may be unable to obtain the corresponding information of the actual service's subscription data. Summary of the Invention

[0005] This application provides a communication method and apparatus. When a session switching event occurs in a dual-connection device, the application function network element can synchronously switch the events subscribed to by the application function network element, so that the application function network element can obtain the correct event information.

[0006] The technical solution is as follows:

[0007] In a first aspect, embodiments of this application provide a communication method, the method comprising: a network exposure function (NET) obtaining a mapping relationship between a first identifier of a terminal device and an identifier of first subscribed data of the terminal device; the NET sends a first request message to a first network element, the first request message requesting subscription to session-related events of the first subscribed data of the terminal device; the NET receives a handover event from the first network element, the handover event indicating that the session of the terminal device is switching from the first subscribed data to the second subscribed data; and the NET sends a second request message to a second network element, the second request message requesting subscription to session-related events of the second subscribed data, the second network element being a network element serving the second subscribed data.

[0008] In this application, the network exposure function (NET) element has a mapping relationship between a first identifier of the terminal device and an identifier of the first subscription data of the terminal device. When the terminal device's session corresponds to the first subscription data, the NET can subscribe to session-related events of the first subscription data from the first network element by sending a first request message. Subsequently, when the terminal device's session switches from the first subscription data to the second subscription data, the NET can, based on the switching event from the first network element, change its subscription from the first network element to the second network element when the terminal device's session switches. Therefore, the NET can synchronously switch the subscription events when the terminal device's session switches, ensuring that the NET obtains the correct events.

[0009] In one possible implementation, the events associated with the session on the second contract data are the same as those associated with the session on the first contract data. In other words, the session on the first contract data and the session on the second contract data are the same session, meaning the session switches from the first contract data to the second contract data.

[0010] In one possible implementation, before the network exposure function network element receives the handover event from the first network element, the method provided in this application may further include: the network exposure function network element sending a subscription request message to the first network element. The subscription request message is used to subscribe to the handover event of the terminal device. This enables the first network element to notify the network exposure function network element of the handover event based on the subscription request message after a handover event occurs in the terminal device.

[0011] In one possible implementation, the network exposure function network element obtains the correspondence between the first identifier of the terminal device and the identifier of the subscribed data, including: the network exposure function network element sending a third request message to a third network element, the third request message including the identifier of the first subscribed data. The third request message requests the third network element to provide the identifier of the terminal device. The network exposure function network element receives the first identifier of the terminal device from the third network element, as well as the identifier of the first subscribed data associated with the first identifier and the identifier of the second subscribed data.

[0012] In one possible implementation, the first identifier is associated with the identifier of the first subscribed data. After the network exposure function element receives a handover event from the first network element, the method provided in this application embodiment further includes: the network exposure function element sending a fourth request message to a third network element, the fourth request message being used to request an update of the mapping relationship. The network exposure function element receives the updated mapping relationship from the third network element, the updated mapping relationship including the association between the first identifier and the identifier of the second subscribed data.

[0013] In one possible implementation, the first identifier is associated with the identifier of the first subscribed data. After the network exposure function element obtains the mapping relationship between the first identifier of the terminal device and the identifier of the subscribed data, the method provided in this application embodiment further includes: the network exposure function element receiving a fourth request message from a fourth network element, the fourth request message including the first identifier. The fourth request message is used to subscribe to session-related events of the first subscribed data and to subscribe to handover events. The network exposure function element sends the fourth request message to the first network element.

[0014] In one possible implementation, after the network exposure function (NET) receives the first information from the first network element, the method provided in this application embodiment further includes: the NET sending a handover event to the fourth network element. The NET receives a fifth request message from the fourth network element, the fifth request message including the address information of the terminal device. The fifth request message is used to indicate obtaining a second identifier. The second identifier is associated with the identifier of the second subscription data. The NET obtains the second identifier of the terminal device from the third network element. The NET sends the second identifier to the fourth network element. The NET receives a sixth request message from the fourth network element, the sixth request message being used to request subscription to session-related events of the second subscription data, and to subscribe to the handover event.

[0015] In one possible implementation, the first and second subscription data belong to the same user within the same operator. This allows for session switching within the same device.

[0016] In one possible implementation, the first request message is also used to subscribe to session-related events for the second contract data.

[0017] Secondly, embodiments of this application provide a communication method, comprising: a unified data management network element receiving a third request message from a network exposure function network element. The third request message includes an identifier of first subscribed data. The third request message requests the third network element to provide an identifier of a terminal device. The unified data management network element sends information about the first identifier to the network exposure function network element. The information about the first identifier includes the first identifier and an identifier of the subscribed data associated with the first identifier.

[0018] In one possible implementation, the information of the first identifier includes: a first identifier of the terminal device, and an identifier of the first subscription data and an identifier of the second subscription data associated with the first identifier.

[0019] In one possible implementation, the method provided in this application further includes: a unified data management network element sending indication information to a network exposure function network element, the indication information being used to indicate that the terminal device is a dual-connectivity device. Indicating that the terminal device is a dual-connectivity device means that a handover event may occur on the terminal device.

[0020] In one possible implementation, the first and second contracted data belong to the same user of the same operator.

[0021] Thirdly, embodiments of this application provide a communication method, comprising: a first access and mobility management function (AMU) network element receiving a first request message from a network exposure function (NET) network element, the first request message being used to subscribe to session-related events of first subscribed data. When a terminal device's session switches from the first subscribed data to the second subscribed data, the first AMU network element sends a handover event to the NET network exposure function network element. The handover event indicates that the terminal device's session has switched from the first subscribed data to the second subscribed data.

[0022] In one possible implementation, the first access and mobility management function network element receives a second request message from the network exposure function network element. The second request message is used to subscribe to a handover event.

[0023] The first access and mobility management function network element is the access and mobility management function network element that serves the terminal device when the terminal device's session is the first subscribed data.

[0024] In one possible implementation, the first request message is also used to subscribe to the terminal device's switching event.

[0025] Fourthly, embodiments of this application provide a communication method, which includes: an application function network element sending a fifth request message to a network exposure function network element. The fifth request message is used to request the acquisition of an identifier of a terminal device. The identifier of the terminal device is used by the network exposure function network element to obtain a mapping relationship between a first identifier of the terminal device and an identifier of subscribed data. The application function network element receives information about the first identifier of the terminal device from the network exposure function network element. The information about the first identifier includes the first identifier and the identifier of the subscribed data associated with the first identifier. The application function network element sends a sixth request message to the network exposure function network element. The sixth request message includes the first identifier and is used to request subscription to session-related events of the first subscribed data.

[0026] In one possible implementation, the information of the first identifier includes: the first identifier, the identifier of the first contract data, and the identifier of the second contract data.

[0027] In one possible implementation, the information of the first identifier includes: the first identifier and the identifier of the first contract data.

[0028] In one possible implementation, the sixth request message is further used to subscribe to a handover event. The method provided in this application embodiment further includes: an application function network element receiving a handover event from a network exposure function network element, the handover event indicating that the terminal device's session is switching from first subscribed data to second subscribed data. The application function network element sends a seventh request message to the network exposure function network element, the seventh request message indicating the acquisition of a second identifier and an identifier of the second subscribed data associated with the second identifier. The application function network element receives the second identifier from the network exposure function network element and the identifier of the second subscribed data associated with the second identifier. The application function network element sends an eighth request message to the network exposure function network element, the eighth request message requesting subscription to session-related events of the second subscribed data and subscribing to the handover event.

[0029] Fifthly, embodiments of this application provide a communication device that can implement the methods in the first aspect or any possible implementation of the first aspect, and therefore can also achieve the beneficial effects of the first aspect or any possible implementation of the first aspect. This communication device can be a network exposure function (NET) element, or an apparatus that supports the implementation of the methods in the first aspect or any possible implementation of the first aspect by the NET element, such as a chip applied in the NET element. This device can implement the above methods through software, hardware, or by hardware executing corresponding software.

[0030] Sixthly, embodiments of this application provide a communication device that can implement the methods in the second aspect or any possible implementation of the second aspect, and therefore can also achieve the beneficial effects of the second aspect or any possible implementation of the second aspect. This communication device can be a unified data management network element, or it can be a device that supports the unified data management network element in implementing the methods in the second aspect or any possible implementation of the second aspect, such as a chip applied in the unified data management network element. This device can implement the above methods through software, hardware, or by hardware executing corresponding software.

[0031] In a seventh aspect, embodiments of this application provide a communication device that can implement the methods in the third aspect or any possible implementation of the third aspect, and therefore can also achieve the beneficial effects of the third aspect or any possible implementation of the third aspect. This communication device can be an access and mobility management function (AMU) network element, or an apparatus that supports the implementation of the methods in the third aspect or any possible implementation of the third aspect in an AMU network element, such as a chip applied in an AMU network element. This device can implement the above methods through software, hardware, or by hardware executing corresponding software.

[0032] Eighthly, embodiments of this application provide a communication device that can implement the methods in the fourth aspect or any possible implementation of the fourth aspect, and thus also achieve the beneficial effects of the fourth aspect or any possible implementation of the fourth aspect. This communication device can be an access and mobility management function (AMU) network element, or an apparatus that supports the implementation of the methods in the fourth aspect or any possible implementation of the fourth aspect in an AMU network element, such as a chip applied in an AMU network element. This device can implement the above methods through software, hardware, or by hardware executing corresponding software.

[0033] Ninthly, embodiments of this application provide a computer-readable storage medium storing a computer program or instructions that, when executed on a computer, cause the computer to perform a communication method as described in any of the possible implementations of the first aspect.

[0034] In a tenth aspect, embodiments of this application provide a computer-readable storage medium storing a computer program or instructions that, when executed on a computer, cause the computer to perform a communication method as described in any of the possible implementations of the second aspect.

[0035] Eleventhly, embodiments of this application provide a computer-readable storage medium storing a computer program or instructions that, when executed on a computer, cause the computer to perform a communication method as described in any of the possible implementations of the third aspect to the third aspect.

[0036] In a twelfth aspect, embodiments of this application provide a computer-readable storage medium storing a computer program or instructions that, when executed on a computer, cause the computer to perform a communication method as described in any of the possible implementations of the fourth aspect to the fourth aspect.

[0037] In a thirteenth aspect, embodiments of this application provide a computer program product including instructions that, when executed on a computer, cause the computer to perform a communication method described in the first aspect or various possible implementations of the first aspect.

[0038] In a fourteenth aspect, embodiments of this application provide a computer program product including instructions that, when executed on a computer, cause the computer to perform a communication method described in the second aspect or various possible implementations of the second aspect.

[0039] In a fifteenth aspect, embodiments of this application provide a computer program product including instructions that, when executed on a computer, cause the computer to perform a communication method described in the third aspect or various possible implementations of the third aspect.

[0040] In a sixteenth aspect, embodiments of this application provide a computer program product including instructions that, when executed on a computer, cause the computer to perform a communication method described in the fourth aspect or various possible implementations of the fourth aspect.

[0041] In a seventeenth aspect, embodiments of this application provide a communication device for implementing various methods in various possible designs of any of the first, second, third, or fourth aspects described above. The communication device can be a network exposure function (NET) element, an apparatus containing a NET, or a component (e.g., a chip) applied to a NET. Alternatively, the communication device can be a unified data management (UDM) element, an apparatus containing a UDM element, or a component (e.g., a chip) applied to a UDM element. Alternatively, the communication device can be an access and mobility management (AMA) element, an apparatus containing an AMA element, or a component (e.g., a chip) applied to an AMA element. Alternatively, the communication device can be an application function (AMA) element, an apparatus containing an AMA element, or a component (e.g., a chip) applied to an application function (AMA) element. The communication device includes modules and units corresponding to the methods described above. These modules and units can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the functions described above.

[0042] It should be understood that the communication device described in aspect seventeen above may further include: a bus and a memory, the memory being used to store code and data. Optionally, at least one processor communication interface and the memory are coupled to each other.

[0043] In an eighteenth aspect, embodiments of this application provide a communication device comprising at least one processor. The at least one processor is coupled to a memory, and when the communication device is in operation, the processor executes computer execution instructions or programs stored in the memory to cause the communication device to perform any of the methods described in the first aspect or any of the various possible designs of the first aspect. For example, the communication device may be a network exposure function (NET) element, or a chip applied to a NET element.

[0044] In a nineteenth aspect, embodiments of this application provide a communication device comprising at least one processor. The at least one processor is coupled to a memory, and when the communication device is in operation, the processor executes computer execution instructions or programs stored in the memory to cause the communication device to perform any of the methods described in the second aspect or any of the various possible designs of the second aspect. For example, the communication device may be a unified data management network element, or a chip applied in a unified data management network element.

[0045] In a twentieth aspect, embodiments of this application provide a communication device comprising: at least one processor. The at least one processor is coupled to a memory, and when the communication device is in operation, the processor executes computer execution instructions or programs stored in the memory to cause the communication device to perform any of the methods described in the third aspect or any of the various possible designs of the third aspect. For example, the communication device may be an access and mobility management function network element, or a chip applied in an access and mobility management function network element.

[0046] In a twentieth aspect, embodiments of this application provide a communication device comprising at least one processor. The at least one processor is coupled to a memory, and when the communication device is in operation, the processor executes computer execution instructions or programs stored in the memory to cause the communication device to perform a method as described in the fourth aspect above, or any of the various possible designs of the fourth aspect. For example, the communication device may be an application function network element, or a chip applied to an application function network element.

[0047] It should be understood that the memory described in any of aspects eighteen to twenty-one may also be replaced by a storage medium, and the embodiments of this application do not limit this.

[0048] In one possible implementation, the memory described in any of aspects eighteen to twenty-one can be internal to the communication device. Of course, the memory can also be located external to the communication device, but at least one processor can still execute computer execution instructions or programs stored in the memory.

[0049] In a twentieth aspect, embodiments of this application provide a communication device comprising one or more modules for implementing the methods of any one of the first, second, third, and fourth aspects described above. The one or more modules may correspond to the various steps in the methods of any one of the first, second, third, and fourth aspects described above.

[0050] In a twenty-third aspect, embodiments of this application provide a chip system including a processor. The processor reads and executes a computer program stored in a memory to perform the methods in the first aspect and any possible implementation thereof. Optionally, the chip system may be a single chip or a chip module composed of multiple chips. Optionally, the chip system further includes a memory, which is connected to the processor via circuitry or wiring. Further optionally, the chip system includes a communication interface. The communication interface is used to communicate with other modules outside the chip.

[0051] In a twentieth aspect, embodiments of this application provide a chip system including a processor. The processor reads and executes a computer program stored in a memory to perform the methods of the second aspect and any possible implementation thereof. Optionally, the chip system may be a single chip or a chip module composed of multiple chips. Optionally, the chip system further includes a memory, which is connected to the processor via circuitry or wiring. Further optionally, the chip system includes a communication interface. The communication interface is used to communicate with other modules outside the chip.

[0052] In a twentieth aspect, embodiments of this application provide a chip system including a processor. The processor reads and executes a computer program stored in a memory to perform the methods of the third aspect and any possible implementation thereof. Optionally, the chip system may be a single chip or a chip module composed of multiple chips. Optionally, the chip system further includes a memory, which is connected to the processor via circuitry or wiring. Further optionally, the chip system includes a communication interface. The communication interface is used to communicate with other modules outside the chip.

[0053] In a twentieth aspect, embodiments of this application provide a chip system including a processor. The processor reads and executes a computer program stored in a memory to perform the methods in the fourth aspect and any possible implementation thereof. Optionally, the chip system may be a single chip or a chip module composed of multiple chips. Optionally, the chip system further includes a memory, which is connected to the processor via circuitry or wiring. Further optionally, the chip system includes a communication interface. The communication interface is used to communicate with other modules outside the chip.

[0054] In a twentieth aspect, embodiments of this application provide a communication system comprising: a network exposure function network element, a first access and mobility management function network element, and a second access and mobility management function network element.

[0055] The network exposure function network element is used to execute the methods in the first aspect and any possible implementation thereof. The first access and mobility management function network element is used to execute the methods in the third aspect and any possible implementation thereof. The second access and mobility management function network element is used to provide the network exposure function network element with session-related events related to the second subscription data.

[0056] Optionally, the communication system may further include: a unified data management network element, wherein the unified data management network element is used to execute the methods in the second aspect and any possible implementation thereof. Optionally, the communication system may further include: an application function network element, wherein the application function network element is used to execute the methods in the fourth aspect and any possible implementation thereof.

[0057] Optionally, the communication system may also include user plane function network elements, which are used to provide identification information for terminal devices.

[0058] Any of the devices, computer storage media, computer program products, chips, or communication systems provided above are used to execute the corresponding methods provided above. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects of the corresponding solutions in the corresponding methods provided above, and will not be repeated here. Attached Figure Description

[0059] Figure 1 is a schematic diagram of the architecture of a communication system provided in an embodiment of this application;

[0060] Figure 2 is a schematic diagram of a 5G network architecture provided in an embodiment of this application;

[0061] Figure 3 is a structural schematic diagram of a dual-connection device provided in an embodiment of this application;

[0062] Figure 4 is a schematic diagram of session splitting and session switching of a dual-connection device provided in an embodiment of this application;

[0063] Figure 5 is a schematic diagram of session splitting and session switching of another dual-connection device provided in an embodiment of this application;

[0064] Figure 6 is a schematic diagram of the process of an AF network element obtaining the identifier of a terminal device according to an embodiment of this application;

[0065] Figure 7 is a schematic diagram of a session establishment process for a terminal device provided in an embodiment of this application;

[0066] Figure 8 is a flowchart illustrating a communication method provided in an embodiment of this application;

[0067] Figure 9 is a schematic diagram illustrating a specific implementation of a communication method provided in an embodiment of this application;

[0068] Figure 10 is a schematic diagram illustrating a specific implementation of another communication method provided in an embodiment of this application;

[0069] Figure 11 is a schematic diagram of a specific implementation of another communication method provided in the embodiments of this application;

[0070] Figure 12 is a schematic diagram of a communication device provided in an embodiment of this application;

[0071] Figure 13 is a schematic diagram of the hardware structure of a communication device provided in an embodiment of this application;

[0072] Figure 14 is a schematic diagram of a chip structure provided in an embodiment of this application. Detailed Implementation

[0073] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B; "and / or" in this text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0074] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this embodiment, unless otherwise stated, "a plurality of" means two or more.

[0075] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0076] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0077] It should be understood that in this application, "at least one (item)" means one or more. "More than one" means two or more. "At least two (items)" means two or three or more. "And / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural.

[0078] The character " / " generally indicates that the preceding and following objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any single or multiple items. For example, "at least one of a, b, or c" can be expressed as: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0079] Both "...when" and "if" indicate that a corresponding action will be taken under certain objective circumstances. They are not time limits, nor do they require a judgment action to be taken when the action is taken, nor do they imply any other limitations.

[0080] The steps involved in the communication method provided in this application embodiment are merely examples. Not all steps are mandatory, nor are all contents of each piece of information or message mandatory. They can be added or removed as needed during use.

[0081] In this application, the same step or a step or message with the same function can be referenced and learned from each other in different embodiments.

[0082] The system architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0083] As shown in Figure 1, Figure 1 is a schematic diagram of the architecture of a communication system provided in the application embodiment. The system includes: a network exposure function network element 120, a first network element 130, a second network element 140, and a third network element 150.

[0084] Among them, network exposure function network element 120, first network element 130, second network element 140, and third network element 150 can be network elements in the core network.

[0085] Optionally, the system may further include a terminal device 110, which may have multiple subscription data sets. The terminal device may use one of these subscription data sets to communicate with the network. For example, the session between the terminal device and the network may be carried on the subscription data set for data transmission.

[0086] For example, terminal device 110 can be a dual-connectivity device, which can have two SIM cards and enable both SIM cards to send and receive data simultaneously; it can also be two completely independent user devices encapsulated in the same device or connected together through other means. Each SIM card or terminal in terminal device 110 corresponds to a subscription data (SUPI). For example, user device 1 corresponds to the first subscription data, and user device 2 corresponds to the second subscription data. Or, SIM card 1 corresponds to the first subscription data SUPI#1, and SIM card 2 corresponds to the second subscription data. The first subscription data corresponds to the first network element 130, and the second subscription data corresponds to the second network element 140. When a session is transmitting data on the first subscription data, because the network signal quality of the first subscription data is poor, terminal device 110 can choose to switch the session to the second subscription data for transmission.

[0087] Among them, the network exposure function element 120 is used to obtain the mapping relationship between the external identifier of the terminal device 110 and the subscription data. For example, the external identifier of the terminal device 110 is associated with the first subscription data, or with the second subscription data, or with both the first and second subscription data.

[0088] Specifically, the first network element 130 corresponds to the first contracted data and is used to provide services for the first contracted data. The second network element 140 corresponds to the second contracted data and is used to provide services for the second contracted data.

[0089] Among them, the third network element 150 is used to determine the mapping relationship between the external identifier of the terminal device 110 and the contracted data.

[0090] The communication system shown in Figure 1 in this application embodiment can be applied to the current fifth-generation (5G) network architecture and future communication network architecture, and this application embodiment does not limit it.

[0091] Figure 2 shows a schematic diagram of the 5G network architecture, which includes: terminal equipment, access network (AN), application function (AF) network elements, network exposure function (NEF) network elements, user plane function (UPF) network elements, unified data management (UDM) network elements, and access and mobility management function (AMF) network elements.

[0092] For example, the network element or entity corresponding to the terminal device 110 in Figure 1 can be a terminal device in the 5G network architecture shown in Figure 2. The network element or entity corresponding to the network exposure function network element 120 in Figure 1 can be a NEF network element in the 5G network architecture shown in Figure 2. The network element or entity corresponding to the first network element 130 or the second network element 140 in Figure 1 can be an AMF network element in the 5G network architecture shown in Figure 2. The network element or entity corresponding to the third network element 150 in Figure 1 can be a UDM network element in the 5G network architecture shown in Figure 2.

[0093] Among them, the terminal device is used to trigger the AF network element to provide services through the application or service request on the terminal device.

[0094] Among them, AN is used to connect terminal equipment to the core network. It is mainly responsible for connecting users' voice, data and other communication services to a wider network to realize the transmission of communication services.

[0095] The AF (Application Server) network element is used to interact with the core network, manage and create various services to provide services to terminal devices. For example, it influences service routing, exposes network access capabilities, interacts with policy decision-making network elements for policy control, and provides information to the core network. The AF network element can be a third-party functional entity or an application service deployed by the operator, such as the IP Multimedia Subsystem (IMS) voice call service. The AF network element can also be referred to as an application server.

[0096] Among them, the NEF network element is used to support the security of interaction between the network side and third-party applications.

[0097] Among them, the UPF network element is used for forwarding and receiving user data in terminal equipment.

[0098] Among them, the UDM network element is used for the management of subscription data of terminal devices, including the storage and management of terminal device identifiers and access authorization of terminal devices.

[0099] The AMF (Access Flow Function) element is responsible for signaling processing, such as access control, mobility management, attach and detach, and gateway selection.

[0100] Optionally, as shown in Figure 2, the communication system shown in Figure 2 may also include: a session management function (SMF) network element, a policy control function (PCF) network element, an authentication server function (AUSF) network element, a network repository function (NRF) network element, a unified data repository (UDR) network element, a network slice selection function (NSSF) network element, and a data network (DN), etc. The embodiments of this application do not specifically limit this.

[0101] The functions of each network element are described below.

[0102] NSSF network elements are primarily used to select the set of network slice instances to serve user equipment (UE).

[0103] NRF network elements can be used to provide network element discovery functionality, providing network element information corresponding to the network element type based on requests from other network elements. NRF network elements also provide network element management services, such as network element registration, updates, deregistration, and network element status subscription and push.

[0104] The PCF network element is primarily responsible for supporting unified policy management of network behavior and providing policy rules to control plane functions for execution. It mainly obtains subscription-related information from the unified data repository (UDR) network element to make policy decisions. The UDR provides storage capabilities for post-subscription data, policy data, and capability-related data.

[0105] The AUSF network element is primarily responsible for processing user authentication data, supporting 3GPP and non-3GPP access authentication, and protecting the requester's "guidance information list" for network functions.

[0106] The SMF network element mainly performs functions such as session management, execution of control policies issued by the PCF network element, selection of the UPF network element, and allocation of Internet Protocol (IP) addresses for terminals.

[0107] A Domain Provider (DN) is a network located outside of the carrier's network. A carrier's network can connect to multiple DNs, and various services can be deployed on a DN, providing data and / or voice services to terminal devices. For example, a DN might be the private network of a smart factory. Sensors installed in the workshop can act as terminal devices, and a control server for these sensors is deployed within the DN. The control server provides services to the sensors. Sensors can communicate with the control server, receive instructions from it, and transmit the collected sensor data back to the control server accordingly. Another example is a DN serving as an internal office network for a company. Employees' mobile phones or computers can act as terminal devices, accessing information and data resources on the company's internal office network.

[0108] In the embodiments of this application, the terminal device may include various handheld devices, vehicle-mounted devices, wearable devices, computing devices, or other processing devices connected to a wireless modem with wireless communication capabilities; it may also include a subscriber unit, cellular phone, smartphone, wireless data card, personal digital assistant (PDA) computer, tablet computer, wireless modem, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, machine type communication (MTC) terminal, user equipment (UE), mobile station (MS), terminal device, or relay user equipment, etc. The relay user equipment may, for example, be a 5G residential gateway (RG). For ease of description, the user equipment mentioned above is collectively referred to as a terminal in this application.

[0109] It should be understood that the terminal in the embodiments of this application can also be a terminal in various vertical industry application fields such as Internet of Things terminal devices, ports, smart factories, railway transportation, logistics, drones, and autonomous vehicles. For example, mobile robots, automated guided vehicles (AGVs), autonomous vehicles, control equipment and sensors on trains, and control equipment and sensors deployed in factories.

[0110] In the embodiments of this application, the AN can be a cellular system related to the 3rd generation partnership project (3GPP), such as a 4G or 5G mobile communication system, an NTN (non-terrestrial network) system, or a future-oriented evolution system (such as a 6G mobile communication system). The access network can also be an open RAN (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) system, or a communication system that integrates two or more of the above systems.

[0111] Access networks, sometimes also called access network equipment, RAN entities, or access nodes, are part of a communication system and are used to help terminals achieve wireless access.

[0112] Access network equipment: A device deployed in a radio access network that meets 4G standards and provides wireless communication functions for terminals, such as an evolved node B (eNB) in a long term evolution (LTE) system. eNBs can include various forms of macro base stations, micro base stations (also called small cells), relay stations, access points, wearable devices, and vehicle-mounted equipment. An eNB can also be a transmission and reception point (TRP).

[0113] Access network equipment: A device deployed in a radio access network that meets 5G standards to provide wireless communication functions for terminals, such as a next-generation base station (g nodeB, gNB). gNBs can include various forms of macro base stations, micro base stations (also known as small stations), relay stations, access points, wearable devices, and vehicle-mounted equipment. gNBs can also be transmission and reception points (TRPs) or transmission measurement functions (TMFs). gNBs can include central units (CUs) and distributed units (DUs) integrated on them.

[0114] In addition, access network equipment can also be a radio network controller (RNC), a radio controller in a cloud radio access network (CRAN) system, a base station controller (BSC), a home base station (e.g., home evolved nodeB, or home node B, HNB), a baseband unit (BBU), a transmitting and receiving point (TRP), a transmitting point (TP), a mobile switching center, a base transceiver station (BTS) in a global system for mobile communication (GSM) or code division multiple access (CDMA) network, a node base station (NB) in a wideband code division multiple access (WCDMA) network, an evolved NB (eNB or eNodeB) in LTE, a base station device in a future network, or an access network device in a future evolved PLMN network, or a wearable device or vehicle-mounted device.

[0115] In Figure 2, the terminal device accesses the network through the AN device, and communicates with the AMF network element through the N1 interface (N1 for short). The SMF network element communicates with the UPF network element through the N4 interface (N4 for short). The UPF network element communicates with the DN through the N6 interface (N6 for short). The AN device communicates with the AMF network element through the N2 interface (N2 for short). The AN device communicates with the UPF network element through the N3 interface (N3 for short).

[0116] Control plane network elements can also interact using service-oriented interfaces. For example, as shown in Figure 1, AMF, SMF, UDM, or PCF network elements interact using service-oriented interfaces. For instance, the service-oriented interface provided by an AMF network element can be Namf. The service-oriented interface provided by an SMF network element can be Nsmf. The service-oriented interface provided by a UDM network element can be Nudm. The service-oriented interface provided by a PCF network element can be Npcf. The service-oriented interface provided by a NEF network element can be Nnef. The service-oriented interface provided by an AF network element can be Naf. The service-oriented interface provided by an NRF network element can be Nnrf. The service-oriented interface provided by an NSSF network element can be Nnssf. The service-oriented interface provided by an AUSF network element can be Nausf. It should be understood that the relevant descriptions of the names of various service-oriented interfaces can be found in the existing 5G system architecture diagram, and will not be elaborated upon here.

[0117] It should be noted that the AN device, AMF network element, SMF network element, UDM network element, UPF network element, and PCF network element in Figure 2 are merely names, and these names do not limit the devices themselves. In 5G networks and other future networks, the network elements or entities corresponding to the AN device, AMF network element, SMF network element, UDM network element, UPF network element, and PCF network element may also have other names, and this application embodiment does not specifically limit them. For example, the UDM network element may also be replaced by a home subscriber server (HSS), a user subscription database (USD), or a database entity, etc. This will be uniformly explained here and will not be elaborated further later.

[0118] In Figure 2, Nnssf, Nnef, Nnrf, Npcf, Nudm, Naf, Neasdf, Nnssaaf, Nausf, Namf, Nsmf, Nnsacf, N1, N2, N3, N4, and N6 are interface sequence numbers. The meanings of these interface sequence numbers can be found in the definitions in the 3GPP standard protocols, and are not limited here.

[0119] It is understood that the aforementioned network elements or functions can be network components in hardware devices, software functions running on dedicated hardware, or virtualization functions instantiated on a platform (e.g., a cloud platform).

[0120] Optionally, the aforementioned network element or function can be implemented by one device, or by multiple devices working together, or it can be a functional module within a device. This application embodiment does not specifically limit this.

[0121] In this embodiment, the terminal device can be a dual-steer device, as shown in Figure 3. Each dual-steer device includes two independent terminal devices. Furthermore, the subscription data of the two terminal devices belongs to the same operator, and their corresponding association is stored in the network.

[0122] As an example, a dual-connectivity device can be a terminal device with two SIM cards that can achieve dual-SIM dual-pass functionality. For instance, both SIM cards can send and receive data simultaneously; one SIM card can be used to play games while the other can be used to make WeChat calls.

[0123] As another example, a dual-connectivity device can also be two completely independent terminal devices that are encapsulated in the same device or connected together in some other way, meaning that the two terminal devices can interact with each other to a certain extent.

[0124] In one possible embodiment of this application, dual-connectivity devices are divided into two types: single UE case and separate UE case. In a single UE case, only one subscription data can be transmitted at a time, lacking dual-transmit and dual-receive capability. A separate UE case, on the other hand, integrates two sets of terminal devices, each with independent transceiver equipment, allowing both terminal devices to transmit and receive data simultaneously.

[0125] In dual-connectivity devices, two concepts are involved: traffic switching and traffic steering.

[0126] Case 1) For single UE case.

[0127] Session splitting refers to the ability of a dual-connection device to select one of two contracted data sets for transmission when data needs to be transmitted. For example, a network can define two contracted data sets: one as the primary contracted data and the other as the backup contracted data. When a service request is received, the primary contracted data is used for data transmission first.

[0128] Session switching refers to the ability of a dual-connectivity device to switch all sessions on one subscription data set to another. For example, if a terminal device is currently transmitting data through two sessions on the primary subscription data set, but the service cannot be guaranteed due to poor network signal quality, the dual-connectivity device can choose to switch the sessions to the backup subscription data set for transmission.

[0129] For example, as shown in Figure 4, which is a schematic diagram of session splitting and session switching in a dual-connectivity device provided in this application, the dual-connectivity device includes two universal subscriber identity modules (USIMs), USIM#1 and USIM#2. USIM#1 accesses the user plane function network element through the access network device RAN#1. Session splitting involves defining the data on USIM#1 as primary subscription data and the data on USIM#2 as backup subscription data, allowing either to be used for data transmission. Session switching involves switching the sessions SDF#1 and SDF#2 on the primary subscription data of USIM#1 to the backup subscription data of USIM#2. USIM#1 accesses the user plane function network element (A-UPF#1 and A-UPF#2) through RAN#1, while USIM#2 accesses the user plane function network element (A-UPF#1 and A-UPF#2) through RAN#2.

[0130] It is worth noting that, since a single UE case cannot transmit data simultaneously, session switching and session offloading can only be performed at the terminal device level.

[0131] Case 2) For separate UE case.

[0132] Session splitting refers to the process by which dual-connected devices select different contracted data transmission methods based on different sessions.

[0133] Session switching refers to the ability of a dual-connectivity device to switch a session from one subscription data set to another. Session switching is performed at the session level.

[0134] For example, as shown in Figure 5, which illustrates another scenario of session splitting and session switching in a dual-connectivity device provided in this application, the dual-connectivity device includes two terminal devices, UE#1 and UE#2. Session splitting means that when the dual-connectivity device obtains services corresponding to SDF#1 and SDF#3, it can transmit data through the subscribed data on UE#1; similarly, when the dual-connectivity device obtains services corresponding to SDF#2, it can also transmit data through the subscribed data on UE#2. UE#1 and UE#2 can transmit data simultaneously. Session switching means that when UE#1 has sessions for both SDF#1 and SDF#3, the dual-connectivity device can choose to switch the SDF#3 session to UE#2 for transmission. In this case, the session switching of SDF#3 does not affect the session of SDF#1.

[0135] It is worth noting that the address of the dual-connection device remains unchanged during session handover; that is, UE#1 and UE#2 will use the same IP address to transmit session data.

[0136] Currently, in some related technologies, for ordinary terminal devices, when running applications, the AF network element needs to obtain the mapping relationship of the external identifier corresponding to the terminal device to enable the transmission of the application's session over the subscription data. Figure 6 shows a schematic diagram of the process by which the AF network element obtains the terminal device's identifier. Specific methods include:

[0137] Step 1: The AF network element sends a UE ID get request message to the NEF network element. Correspondingly, the NEF network element receives the UE ID get request message from the AF network element.

[0138] The request message includes the address information of the terminal device and the identification information of the AF network element.

[0139] Optionally, AF elements can also provide session-related information, such as slice information and data network name (DNN).

[0140] Step 2: The NEF network element authenticates the acquisition request message of the AF network element.

[0141] Step 3: The NEF network element sends an NF discovery request message to the NRF network element. Correspondingly, the NRF network element receives the NF discovery request message from the NEF network element.

[0142] Among them, the network element query request message is used to query UPF network elements.

[0143] As an example, the NEF network element queries the corresponding UPF network element based on S-NSSAI and DNN. S-NSSAI and DNN can be provided by the AF network element in step 1, or they can be obtained by the NRF network element based on the identifier of the AF network element.

[0144] Step 4: The NRF network element sends an NF discovery response message to the NEF network element. Correspondingly, the NEF network element receives the NF discovery response message from the NRF network element.

[0145] The network element query response message includes information about the UPF network element.

[0146] Step 5: The NEF network element sends a request message (get request) to the UPF network element. Correspondingly, the UPF network element receives the request message from the NEF network element.

[0147] The request message is used to request the private address information (UE Private IP address And ID) of the terminal device.

[0148] As an example, the UPF network element requests the private address information of the terminal device based on the terminal device's address information, slice information, and DNN.

[0149] Step 6: The UPF network element sends a response message (get response) to the NEF network element. Correspondingly, the NEF network element receives the response message from the UPF network element.

[0150] The response message includes the terminal device's private address information.

[0151] Step 7: The NEF network element sends a management discovery request message to the BSF network element. Correspondingly, the BSF network element receives the request message from the NEF network element.

[0152] The request message is used to request the identification information of the terminal device.

[0153] As an example, the NEF network element requests the terminal device's identification information from the BSF network element based on the terminal device's private address information, slice information, and DNN.

[0154] Step 8: The BSF network element sends a response message (management discovery response) to the NEF network element. Correspondingly, the NEF network element receives the response message from the BSF network element.

[0155] The response message includes the terminal device's subscription permanent identifier (SUPI).

[0156] As an example, BSF network elements determine the SUPI of a terminal device based on the terminal device's private address information, slice information, and DNN.

[0157] Step 9: The NEF network element sends a request message (get request) to the UDM network element. Correspondingly, the UDM network element receives the request message from the NEF network element.

[0158] The request message is used to request the identification information of a terminal device specific to the AF network element. This identification information also carries the identification information of the SUPI and the AF network element.

[0159] Step 10: The UDM network element sends a response message (get response) to the NEF network element. Correspondingly, the NEF network element receives the response message from the UDM network element.

[0160] The response message includes the identification information of the terminal device specific to the AF network element, and this identification information is unique to the AF network element.

[0161] Step 11: The NEF network element sends the identification information of the AF-specific terminal device to the AF network element. Correspondingly, the AF network element receives the identification information of the AF-specific terminal device from the NEF network element.

[0162] In other related technologies, the session establishment process for terminal devices is shown in Figure 7, and the specific methods are as follows:

[0163] Step 1: The AF network element sends an event subscription request message to the NEF network element. Correspondingly, the NEF network element receives the event subscription request message from the AF network element.

[0164] The event subscription request message includes identifiers for one or more corresponding events. If it is an event report related to a specific terminal device, the identifier of the corresponding terminal device must also be included.

[0165] Step 2: The NEF network element sends a subscription message to the UDM network element. Correspondingly, the UDM network element receives the subscription message from the NEF network element.

[0166] Among them, subscribing to messages is used to subscribe to the corresponding events.

[0167] Step 3: UDM sends a subscription request message to AMF / SMF based on the event information corresponding to the terminal device.

[0168] Specifically, it includes:

[0169] Step 3a: The UDM network element sends a subscription request message to the AMF network element. Correspondingly, the AMF network element receives the subscription request message from the UDM network element.

[0170] Step 3b: The AMF network element sends a subscription response message to the UDM network element. Correspondingly, the UDM network element receives the subscription response message from the AMF network element.

[0171] Step 3c: The UDM network element sends a subscription request message to the SMF network element. Correspondingly, the SMF network element receives the subscription request message from the UDM network element.

[0172] Step 3d: The SMF network element receives the notification message from the UPF network element. The corresponding UPF network element sends a notification message to the SMF network element. The notification message is used to indicate a session update.

[0173] Step 3e: The SMF network element subscribes to events through the UPF network element.

[0174] Step 3f: The SMF network element sends a subscription response message to the UDM network element. Correspondingly, the UDM network element receives the subscription response message from the SMF network element.

[0175] Step 4: The UDM network element sends a response message to the NEF network element. Correspondingly, the NEF network element receives the response message from the UDM network element.

[0176] The response message is used to notify NEF network elements that the subscription is complete.

[0177] Step 5: The NEF network element sends a response message to the AF network element. Correspondingly, the AF network element receives the response message from the NEF network element.

[0178] The response message indicates that the current subscription has been completed.

[0179] Step 6: The NEF network element receives the subscribed event.

[0180] Among them, depending on the events subscribed to, different network elements can trigger the sending of subscribed events to the NEF network element when different triggering conditions are met.

[0181] For example, a UDM network element triggers a subscription event to send to a NEF network element, including:

[0182] Step 6a: The UDM network element sends a notification message to the NEF network element. Correspondingly, the NEF network element receives the notification message from the UDM network element.

[0183] Step 6b: The NEF network element sends a create / update data message to the UDR network element. Correspondingly, the UDR network element receives the create / update data message from the NEF network element.

[0184] For example, an AMF network element triggers a subscription event to send to a NEF network element, including:

[0185] Step 6c: The AMF network element sends a notification message to the NEF network element. Correspondingly, the NEF network element receives the notification message from the AMF network element.

[0186] Step 6d: The NEF network element sends a create / update data message to the UDR network element. Correspondingly, the UDR network element receives the create / update data message from the NEF network element.

[0187] For example, an SMF network element triggers a subscription event to send to a NEF network element, including:

[0188] Step 6e: The SMF network element sends a notification message to the NEF network element. Correspondingly, the NEF network element receives the notification message from the SMF network element.

[0189] Step 6f: The NEF network element sends a create / update data message to the UDR network element. Correspondingly, the UDR network element receives the create / update data message from the NEF network element.

[0190] For example, a UPF network element triggers a subscription event to send to a NEF network element, including:

[0191] Step 6g: The UPF network element sends a notification message to the NEF network element. Correspondingly, the NEF network element receives the notification message from the UPF network element.

[0192] Step 6h: The NEF network element sends a create / update data message to the UDR network element. Correspondingly, the UDR network element receives the create / update data message from the NEF network element.

[0193] Step 7: The NEF network element sends event information to the AF network element. Correspondingly, the AF network element receives the event information from the NEF network element.

[0194] Step 8: The AMF network element sends event information to the UDM network element. Correspondingly, the UDM network element receives the event information from the AMF network element.

[0195] Based on the above description of existing technologies, for ordinary terminal devices, when an AF network element subscribes to events related to the terminal device, it can first map the terminal device's address, obtain the terminal device's identifier, and then subscribe to the corresponding event. However, for dual-connectivity devices, due to session switching (the session may switch from one subscription data to another), the mapping relationship stored by the AF network element remains unchanged because the terminal device's address information does not change. This leads to the AF network element being unable to obtain the corresponding information of the actual service subscription data. Therefore, how to synchronously switch the AF network element's event subscriptions during session switching in dual-connectivity devices, enabling the AF network element to obtain the correct event information, is a problem that urgently needs to be solved.

[0196] Based on this, embodiments of this application provide a communication method. In this method, if the terminal device is a dual-connection device, the NEF network element can map both subscription data when mapping the address information of the terminal device to an external identifier. When a session switch occurs on the terminal device, the NEF network element re-triggers event subscription, enabling the AF network element to correctly obtain the event information corresponding to the subscription data. Alternatively, the AMF network element reports a switch event to the NEF network element. After the session switch occurs, the NEF network element re-executes the terminal device identifier information acquisition process, re-maps the address information to a corresponding terminal device identifier, and subscribes to the corresponding event, enabling the AF network element to obtain the correct event information. Alternatively, the NEF network element reports the corresponding session switch event to the AF network element, letting the AF network element know that a session switch event has occurred on the terminal device, thereby determining whether to re-subscribe to the event.

[0197] In this application embodiment, the specific structure of the execution subject of a communication method is not particularly limited, as long as communication can be performed according to the communication method of this application embodiment by running a program that records the code of the communication method of this application embodiment. For example, the execution subject of a communication method provided in this application embodiment can be a functional module in a network exposure function network element that can call and execute a program, or a communication device applied in a network exposure function network element, such as a chip, chip system, integrated circuit, etc. These chips, chip systems, and integrated circuits can be located inside the network exposure function network element, or they can be independent of the network exposure function network element, and this application embodiment does not impose any restrictions. For example, the execution subject of a communication method provided in this application embodiment can be a functional module in a unified data management network element that can call and execute a program, or a communication device applied in a unified data management network element, such as a chip, chip system, integrated circuit, etc. These chips, chip systems, and integrated circuits can be located inside the unified data management network element, or they can be independent of the unified data management network element, and this application embodiment does not impose any restrictions. For example, the execution entity of a communication method provided in this application embodiment can be a functional module in an access and mobility management function (AMU) network element capable of calling and executing a program, or a communication device applied in an AMU network element, such as a chip, chip system, integrated circuit, etc. These chips, chip systems, and integrated circuits can be located within the AMU network element or can be independent of the AMU network element; this application embodiment does not impose any limitations. Similarly, the execution entity of a communication method provided in this application embodiment can be a functional module in an application function network element capable of calling and executing a program, or a communication device applied in an application function network element, such as a chip, chip system, integrated circuit, etc. These chips, chip systems, and integrated circuits can be located within the application function network element or can be independent of the application function network element; this application embodiment does not impose any limitations.

[0198] The following describes an embodiment of a communication method using a network exposure function (NEF) network element as the executing entity. Unless otherwise specified, the following embodiments can be combined. For ease of description, the network exposure function network element is abbreviated as NEF network element, the unified data management network element as UDM network element, the access and mobility management function network element as AMF network element, and the application function network element as AF network element.

[0199] As shown in Figure 8, Figure 8 illustrates a flowchart of a communication method provided in an embodiment of this application. The method includes:

[0200] Step 801: The NEF network element obtains the mapping relationship between the first identifier of the terminal device and the identifier of the first subscription data of the terminal device.

[0201] Among them, the first identifier of the terminal device is the external identifier corresponding to the terminal device, which is an identifier used to identify user subscription information in non-access networks.

[0202] The first contract data refers to the contract data currently corresponding to the session of the terminal device. The mapping relationship between the first identifier of the terminal device and the identifier of the first contract data of the terminal device can be used to reflect that the contract data currently corresponding to the session of the terminal device is the first contract data. In other words, the mapping relationship between the first identifier of the terminal device and the identifier of the first contract data of the terminal device can also be described as the first identifier of the terminal device being associated or corresponding to the identifier of the first contract data of the terminal device, etc., and this application embodiment does not limit this.

[0203] The subscription data is used for data transmission between the terminal device and the network. The subscription data can be identified by a subscription permanent identifier (SUPI). For example, the subscription permanent identifier (SUPI) is simply a SUPI. Of course, the subscription data can also be identified by other identifiers or information specifically assigned to the subscription data for identification. In the case of a dual-connectivity terminal device, the terminal device can include at least two subscription data sets.

[0204] As an example, the terminal device is a dual-connectivity device including user equipment 1 and user equipment 2. User equipment 1 has SIM card 1, which corresponds to subscription data 1. User equipment 2 has SIM card 2, which corresponds to subscription data 2. Subscription data 1 is identified by SUPI#1 of user equipment 1. Subscription data 2 is identified by SUPI#2 of user equipment 2. Alternatively, the terminal device has two SIM cards, namely SIM card 1 and SIM card 2. SIM card 1 corresponds to subscription data 1, and SIM card 2 corresponds to subscription data 2. Subscription data 1 is identified by SUPI#1 of SIM card 1. Subscription data 2 is identified by SUPI#2 of SIM card 1.

[0205] The correspondence between the first identifier of the terminal device and the identifier of the contracted data can be either the first identifier corresponding to the identifier of one contracted data or the first identifier corresponding to the identifier of two contracted data.

[0206] For example, when user equipment 1 communicates with the network, it uses subscription data 1 for data transmission, and the external identifier of the terminal device corresponds to the identifier SUPI#1 of subscription data 1; when user equipment 2 communicates with the network, it uses subscription data 2 for data transmission, and the external identifier of the terminal device corresponds to the identifier SUPI#2 of subscription data 2. Alternatively, the external identifier of the terminal device may correspond to both the identifier SUPI#1 of subscription data 1 and the identifier SUPI#2 of subscription data 2.

[0207] In one possible implementation, the NEF network element obtains the address information of the terminal device, and then uses this address information to retrieve the mapping between the terminal device's first identifier and the identifier of the subscription data from the UDM network element. The UDM network element is used to determine the mapping between the external identifier corresponding to the terminal device and the identifier of the subscription data based on the terminal device's address information.

[0208] As an example, a NEF network element can obtain the mapping relationship between the first identifier of a terminal device and the identifier of the first subscription data of the terminal device from a UDM network element. For instance, the NEF network element can obtain this mapping relationship from the UDM network element in the following way: In one possible implementation, the NEF network element sends a request message to the UDM network element, which includes the address information of the terminal device. The UDM network element then uses this address information to determine the correspondence between the external identifier of the terminal device and the identifier of the subscription data.

[0209] Step 802: The NEF network element sends a first request message to the first network element. Correspondingly, the first network element receives the first request message from the NEF network element.

[0210] The first request message is used to subscribe to session-related events of the first subscribed data on the terminal device. For example, the first request message includes the session identifier and the identifier of the first subscribed data.

[0211] For example, if a terminal device needs a certain service from the network, the terminal device establishes a session with the network and transmits data through the first subscription data. The event corresponding to this service is an event related to this session.

[0212] As an example, the first network element is the first AMF network element. The NEF network element sends a first request message to the first AMF network element to request subscription to session-related events of the first subscribed data. Here, the first AMF network element corresponds to the first subscribed data, and the first AMF network element is used to serve the first subscribed data. It can be understood that the first AMF network element corresponds to the session-related events of the first subscribed data. Alternatively, it can be understood that the first AMF network element is the AMF network element that provides services to the terminal device when the terminal device uses the first subscribed data for service transmission.

[0213] It is understandable that after the first network element receives the first request message, the first network element can provide the NEF network element with session-related events related to the first subscription data of the terminal device.

[0214] Step 803: The first network element sends the first information to the NEF network element. Correspondingly, the NEF network element receives the first information from the first network element.

[0215] As an example, the first network element is the first AMF network element, which sends the first information to the NEF network element.

[0216] The first piece of information indicates that a handover event has occurred on the terminal device. A handover event, also known as a session handover event, refers to a switch in the terminal device's session from first subscription data to second subscription data, or vice versa. The second subscription data is associated with the first subscription data.

[0217] For example, consider a dual-connectivity terminal device, comprising User Equipment 1 and User Equipment 2. User Equipment 1 corresponds to the first subscription data, and User Equipment 2 corresponds to the second subscription data. The first subscription data corresponding to User Equipment 1 carries one or more sessions and is connected to the UPF network element through the RAN device. After a session handover event occurs on the terminal device, the associated subscription data changes from the first subscription data to the second subscription data.

[0218] In one possible implementation of this application, when the first network element detects that the subscription data of the terminal device's session has switched from the first subscription data to the second subscription data, the first network element may send a switching event to the NEF network element based on the first request message or by actively sending a switching event.

[0219] In another possible implementation of this application, before step 803, the NEF network element sends a subscription request message to the first network element, and correspondingly, the first network element receives the subscription request message from the NEF network element. The subscription request message is used to subscribe to a handover event. When a session handover event occurs at the terminal device, the first network element sends first information to the NEF network element.

[0220] In another possible implementation, in step 802, the first request message can also be used to subscribe to a handover event. When a session handover event occurs at the terminal device, the first network element sends the first information to the NEF network element.

[0221] Step 804: The NEF network element sends a second request message to the second network element. Correspondingly, the second network element receives the second request message from the NEF network element.

[0222] The second request message is used to request subscription to events related to the session of the second contracted data.

[0223] For example, if a terminal device needs a certain service from the network, the terminal device establishes a session with the network and transmits data through a second subscription data. The event corresponding to this service is an event related to this session.

[0224] As an example, the second network element is the second AMF network element. The NEF network element sends a second request message to the second AMF network element to request subscription to session-related events of the second subscribed data. The second AMF network element is associated with the identifier of the second subscribed data and is used to serve the second subscribed data. It can be understood that the second AMF network element corresponds to the session-related events of the second subscribed data.

[0225] In one possible embodiment of this application, the session-related events of the second contracted data are the same as those of the first contracted data; that is, the sessions on the second contracted data and the first contracted data are the same. In other words, the events subscribed to by the first contracted data are switched to the second contracted data, and the subscribed events are the same, only the contracted data is different.

[0226] It is understandable that the first and second contract data belong to the same user from the same operator.

[0227] In one possible embodiment of this application, the first request message is also used to subscribe to session-related events of the second contract data.

[0228] For example, before step 803, the terminal device needs the network to provide a certain service. The terminal device establishes a session with the network and transmits data using second subscription data. In other words, the second subscription data is the subscription data before the terminal device performs a session switch. After the terminal device performs a session switch, the terminal device's session switches from the second subscription data to the first subscription data.

[0229] In this application, the network exposure function (NET) element has a mapping relationship between a first identifier of the terminal device and an identifier of the first subscription data of the terminal device. When the terminal device's session corresponds to the first subscription data, the NET can subscribe to session-related events of the first subscription data from the first network element by sending a first request message. Subsequently, when the terminal device's session switches from the first subscription data to the second subscription data, the NET can, based on the switching event from the first network element, change its subscription from the first network element to the second network element when the terminal device's session switches. Therefore, the NET can synchronously switch the subscription events when the terminal device's session switches, ensuring that the NET obtains the correct events.

[0230] In one possible embodiment of this application, the correspondence between the first identifier of the terminal device and the identifier of the contracted data in step 701 above can be divided into two cases.

[0231] Case 1) The correspondence between the first identifier of the terminal device and the identifier of the contract data is that the first identifier corresponds to the identifier of the first contract data and the identifier of the second contract data.

[0232] Based on the correspondence between the first identifier of the terminal device and the identifier of the first contract data and the identifier of the second contract data, the method provided in this application includes:

[0233] Step a1: The NEF network element sends a third request message to the third network element. Correspondingly, the third network element receives the third request message from the NEF network element.

[0234] The third request message is used to request information about the first identifier of the terminal device.

[0235] As an example, the third request message includes the identifier of the terminal device (UE ID).

[0236] Step a2: The third network element establishes the association between the first contract data and the second contract data based on the third request message.

[0237] In one possible implementation, the third network element determines that the terminal device is a dual-connection device based on the identifier of the terminal device in the third request message, that is, it determines that there is an associated contract data for one contract data, and associates the first identifier with the two contract data.

[0238] For example, the third network element is a UDM network element. Based on the UE ID, the UDM network element determines the first subscription data and confirms that the terminal device supports dual connectivity. At this point, the UDM network element associates the first subscription data with the second subscription data. Simultaneously, the UDM network element maps the terminal device's first identifier to both the first and second subscription data.

[0239] Step a3: The third network element sends the first identifier information to the NEF network element. Correspondingly, the NEF network element receives the first identifier information from the third network element.

[0240] The information of the first identifier includes the first identifier, the identifier of the first contract data, and the identifier of the second contract data.

[0241] Step a4: The NEF network element stores the information of the first identifier.

[0242] Since the information of the first identifier stored in the NEF network element indicates that the first identifier of the terminal device corresponds to both the first subscription data and the second subscription data, when the NEF network element requests a subscription event, if the event corresponds to the first subscription data, then step 802 in the above embodiment is executed. If the event corresponds to the second subscription data, then step 804 in the above embodiment is executed, for example, when the NEF network element receives the first information.

[0243] Case 2) The correspondence between the first identifier of the terminal device and the identifier of the contracted data is that the first identifier corresponds to the identifier of the first contracted data.

[0244] In one possible embodiment of this application, the UDM network element does not associate the first identifier of the terminal device with the two subscription data.

[0245] In one possible implementation of this application, based on the correspondence between the first identifier of the terminal device and the identifier of the first contract data, the method provided in this embodiment of the application further includes, after step 803:

[0246] Step b1: The NEF network element sends a fourth request message to the third network element. Correspondingly, the third network element receives the fourth request message from the NEF network element.

[0247] The fourth request message is used to request an update to the mapping relationship between the first identifier and the contract data.

[0248] As an example, the third network element is a UDM network element. After receiving the fourth request message, the UDM network element matches the first identifier with the second contract data. At this time, the first identifier of the terminal device corresponds to the identifier of the second contract data.

[0249] In one possible implementation, the NEF network element requests the identifier of the terminal device from the UPF network element. After receiving the identifier of the terminal device from the UPF network element, the NEF network element sends a fourth request message to the UDM network element.

[0250] Step b2: The NEF network element receives the updated mapping relationship from the third network element. The updated mapping relationship associates the first identifier with the identifier of the second contract data.

[0251] As an example, the third network element sends an acknowledgment message to the NEF network element. The acknowledgment message is used to confirm the update of the first identifier. The acknowledgment message includes information about the first identifier.

[0252] After step b2, since the first identifier of the terminal device is associated with the identifier of the second subscription data, and the second subscription data corresponds to the second network element, the NEF network element sends a second request message to the second network element to request the subscription of session-related events of the second subscription data.

[0253] In another possible implementation of this application, based on the correspondence between the first identifier of the terminal device and the identifier of the first contract data, the method provided in this application embodiment further includes, after step 801:

[0254] Step c1: The NEF network element receives a fourth request message from the fourth network element. The fourth request message includes a first identifier. The fourth request message is used to request session-related events for subscribing to the first subscribed data, as well as for subscribing to handover events.

[0255] As an example, the fourth network element is the AF network element, which sends a fourth request message to the NEF network element.

[0256] In one possible implementation, the AF network element does not consider whether the terminal device is a dual-connection device and sends a fourth request message to any terminal device to subscribe to the handover event.

[0257] In another possible implementation, in step 701 above, when the NEF network element obtains the mapping relationship between the first identifier and the identifier of the subscription data from the UDM network element, it simultaneously obtains information from the UDM network element regarding whether the terminal device is a dual-connectivity device. If the terminal device is a dual-connectivity device, the NEF network element receives this information and sends it to the AF network element. Based on the information that the terminal device is a dual-connectivity device, the AF network element sends a fourth request message to the NEF network element.

[0258] For example, the UDM network element sends an indication message to the NEF network element, which is used to indicate that the terminal device is a dual-connection device.

[0259] Step c2: The NEF network element sends a fourth request message to the first network element. Correspondingly, the first network element receives the fourth request message from the NEF network element.

[0260] Among them, the first network element is the first AMF network element, and the first AMF network element corresponds to the first contracted data.

[0261] In one possible embodiment of this application, after the NEF network element receives the first information from the first network element, the method provided in this application embodiment further includes:

[0262] Step c3: The NEF network element sends the first information to the fourth network element. Correspondingly, the fourth network element receives the first information from the NEF network element.

[0263] As an example, the fourth network element is the AF network element. The NEF network element sends a notification message to the AF network element. The notification message includes first information to indicate that the terminal device has undergone a session handover.

[0264] Step c4: The NEF network element receives a fifth request message from the fourth network element. The fifth request message is used to instruct the acquisition of the second identifier, which corresponds to the identifier of the second contract data.

[0265] As an example, the fourth network element is the AF network element, which sends a fifth request message to the NEF network element.

[0266] Step c5: The NEF network element obtains the information of the second identifier.

[0267] As an example, the UDM network element sends information about the second identifier to the NEF network element. The information about the second identifier includes the correspondence between the second identifier and the identifier of the second contract data.

[0268] Step c6: The NEF network element sends the second identifier information to the fourth network element. Correspondingly, the fourth network element receives the second identifier information from the NEF network element.

[0269] Step c7: The NEF network element receives the sixth request message from the fourth network element. The sixth request message is used to request session-related events for subscribing to the second subscription data, as well as for subscription handover events.

[0270] As an example, the fourth network element is the AF network element, which sends a sixth request message to the NEF network element.

[0271] In step c7, which is similar to step c1, after a session switching event occurs at the terminal, the NEF network element switches from requesting event subscription from the first AMF network element to requesting event subscription from the second AMF network element.

[0272] Step c8: The NEF network element sends a sixth request message to the second network element. Correspondingly, the second network element receives the sixth request message from the NEF network element.

[0273] Among them, the second network element is the second AMF network element, and the second AMF network element corresponds to the second contracted data.

[0274] The following embodiment uses a terminal device as a dual-connectivity device, a first network element as a first AMF network element, a second network element as a second AMF network element, a third network element as a UDM network element, and a fourth network element as an AF network element. The AF network element subscribes to session-related events related to the subscription data corresponding to the terminal device, and the terminal device may experience a session switching event. The following describes the specific implementation method of switching the AF network element subscription event after a session switching occurs on the terminal device.

[0275] As shown in Figure 9, Figure 9 is a schematic diagram illustrating a specific implementation of a communication method provided in an embodiment of this application. In the embodiment shown in Figure 9, the NEF network element stores the mapping relationship between the terminal device and two subscription data. The specific method includes:

[0276] Step 901: The AF network element sends an eighth request message to the NEF network element. Correspondingly, the NEF network element receives the eighth request message from the AF network element.

[0277] The eighth request message is used to request the identification information of the terminal device.

[0278] As an example, the eighth request message sent by the AF network element to the NEF network element includes the address information of the terminal device (UE IP). Optionally, the eighth request message may also include the identifier of the AF network element (AF ID) and session-related information (such as slice information and data network name).

[0279] Step 902: The NEF network element sends a request message to the UPF network element. Correspondingly, the UPF network element receives the request message from the NEF network element.

[0280] This request message is used to request the identification information of the terminal device.

[0281] As an example, the request message sent by the NEF network element to the UPF network element includes the address information of the terminal device (UE IP).

[0282] It is understandable that steps 901 to 902 are the process by which the AF network element requests the identification information of the terminal device from the UPF network element based on the address information of the terminal device through the NEF network element.

[0283] Step 903: The UPF network element sends a first feedback message to the NEF network element. Correspondingly, the NEF network element receives the first feedback message from the UPF network element.

[0284] The first feedback message includes the identification information of the terminal device.

[0285] As an example, after receiving the request message, the UPF network element determines the identification information of the terminal device based on the address information of the terminal device, and sends the identification information of the terminal device to the NEF network element.

[0286] Step 904: The NEF network element sends a third request message to the UDM network element. Correspondingly, the UDM network element receives the third request message from the NEF network element.

[0287] The third request message is used to request the external identifier corresponding to the terminal device. The external identifier corresponding to the terminal device corresponds to the subscription data.

[0288] For example, the external identifier corresponding to the terminal device is mapped to the identifier of the first contract data (e.g., SUPI1), or the external identifier corresponding to the terminal device is mapped to the identifier of the second contract data (SUPI2); or the external identifier corresponding to the terminal device is mapped to the identifier of the first contract data and the identifier of the second contract data (SUPI1 and SUPI2).

[0289] As an example, the third request message includes an identifier of the terminal device's subscription data, such as the identifier of the first subscription data (SUPI1).

[0290] Step 905: The UDM network element determines the association between the first contract data and the second contract data based on the identifier of the first contract data of the terminal device, and associates the first contract data and the second contract data with the corresponding external identifier of the terminal device.

[0291] As an example, the UDM network element determines, based on the first subscription data, that the first subscription data supports dual-connectivity devices. Supporting dual-connectivity devices means that the first subscription data has an associated subscription data, namely, the second subscription data.

[0292] In one possible implementation, when mapping the external identifier corresponding to the terminal device, the UDM network element associates the external identifier corresponding to the terminal device with the identifier of the first subscription data (SUPI1) and the identifier of the second subscription data (SUPI2). The external identifier corresponding to the terminal device simultaneously corresponds to the first subscription data and the second subscription data.

[0293] Step 906: The UDM network element sends the external identifier corresponding to the terminal device to the NEF network element. Correspondingly, the NEF network element receives the external identifier corresponding to the terminal device from the UDM network element.

[0294] The external identifier corresponding to the terminal device also includes the mapping relationship of the external identifier, that is, the external identifier corresponding to the terminal device corresponds to the first contract data and the second contract data.

[0295] Step 907: The NEF network element stores the external identifier corresponding to the terminal device.

[0296] As an example, the NEF network element also includes the mapping relationship of the external identifier corresponding to the terminal device, that is, the correspondence between the external identifier of the terminal device and the first contract data and the second contract data.

[0297] Step 909: The NEF network element sends the external identifier corresponding to the terminal device to the AF network element. Correspondingly, the AF network element receives the external identifier corresponding to the terminal device from the NEF network element.

[0298] Step 909: The AF network element sends a ninth request message to the NEF network element. Correspondingly, the NEF network element receives the ninth request message from the AF network element.

[0299] The ninth request message is used to request the subscription of session-related events for the first subscribed data. The session-related events for the first subscribed data are the events corresponding to the services in the AF network element.

[0300] As an example, the ninth request message includes an external identifier corresponding to the terminal device.

[0301] Step 910: The NEF network element sends a first request message to the first AMF network element. The first AMF network element receives the first request message from the NEF network element.

[0302] The first request message is used to subscribe to session-related events for the first contracted data.

[0303] As an example, the first request message includes an external identifier corresponding to the terminal device.

[0304] In one possible implementation, the NEF network element determines the first subscription data corresponding to the external identifier of the terminal device based on the external identifier of the terminal device in the ninth request message, and requests to subscribe to the session-related events of the first subscription data based on the first subscription data.

[0305] Step 911: The NEF network element sends a subscription request message to the first AMF network element. Correspondingly, the first AMF network element receives the subscription request message from the NEF network element.

[0306] The subscription request message is used to request a session switching event from the terminal device.

[0307] Among them, the first AMF network element is the AMF network element corresponding to the session-related event of the first signed data.

[0308] In one possible implementation, the NEF network element determines that the terminal device is a dual-connectivity device based on the mapping relationship between the external identifier corresponding to the terminal device in the first request message, that is, the mapping between the external identifier corresponding to the terminal device and the identifier of the first subscription data and the identifier of the second subscription data. Since dual-connectivity devices may experience session switching, the NEF network element subscribes to the session switching events of the terminal device.

[0309] It is worth noting that step 911 can be triggered simultaneously with step 910, meaning the NEF network element can simultaneously send a first request message and a subscription request message to the first AMF network element; the order is not limited in this embodiment. Alternatively, the first request message may include a subscription request message, meaning the first request message can also be used to subscribe to a session switching event of the terminal device. Alternatively, step 911 can be triggered after step 907, meaning that when the NEF network element saves the external identifier corresponding to the terminal device, and the external identifier corresponding to the terminal device corresponds to the first subscription data, it determines that the terminal device may experience a session switching event, and therefore sends a third subscription request message to the first AMF network element.

[0310] Optionally, in step 912, the terminal device performs a session switching event.

[0311] As an example, the terminal device switches the session from the first subscription data to the second subscription data.

[0312] Step 913: The first AMF network element confirms that a session handover event has occurred and sends a notification message to the NEF network element. Correspondingly, the NEF network element receives the notification message from the first AMF network element.

[0313] The notification message is used to indicate that a session switching event has occurred.

[0314] It is understandable that, based on the subscription request message sent by the NEF network element to the first AMF network element in step 911, when a session switching event occurs in the terminal device, the first AMF network element responds to the subscription request message and notifies the NEF network element that a session switching event has occurred.

[0315] Step 914: The NEF network element sends a second request message to the second AMF network element. Correspondingly, the second AMF network element receives the second request message from the NEF network element.

[0316] The second request message is used to request session-related events for the second contract data. The session-related events for the second contract data are the events corresponding to the services in the AF network element after the session switch.

[0317] Among them, the second AMF network element is the AMF network element corresponding to the session-related events of the second contract data.

[0318] In one possible implementation, in step 907, the NEF network element stores the mapping relationship of the external identifier corresponding to the terminal device. Therefore, the NEF network element can determine that after the session handover event occurs, the subscription data corresponding to the external identifier of the terminal device changes from the first subscription data to the second subscription data, that is, the first AMF network element becomes the second AMF network element.

[0319] In another possible implementation, in step 913, the first AMF network element sends a notification message to the NEF network element while simultaneously sending the second subscription data to the NEF network element. The NEF network element can then send a second request message to the second AMF network element based on the second subscription data.

[0320] In the embodiment shown in Figure 9, the NEF network element only needs to acquire and save the mapping relationship between the external identifier of the current terminal device and the identifier of the subscription data, that is, the external identifier of the terminal device, the identifier of the first subscription data, and the identifier of the second subscription data. When a session switching event occurs on the terminal device, the NEF network element can re-initiate event subscription based on the saved mapping relationship, thereby enabling the NEF network element to subscribe to the relevant events of the subscription data actually served by the current AF network element.

[0321] As shown in Figure 10, Figure 10 is a schematic diagram illustrating another specific implementation of the communication method provided in this application embodiment. In this embodiment, the difference from the embodiment shown in Figure 9 is that the mapping relationship of the external identifier corresponding to the terminal device remains unchanged, that is, the external identifier corresponding to the terminal device corresponds to the first subscription data. Only after the session switching event of the terminal device is completed will the NEF network element trigger the update of the mapping relationship of the external identifier corresponding to the terminal device and re-trigger the event subscription. The specific method includes:

[0322] Steps 1001 to 1004 are the same as steps 901 to 904 in the above embodiments, and will not be repeated here.

[0323] Step 1005: The UDM network element sends the external identifier corresponding to the terminal device to the NEF network element. Correspondingly, the NEF network element receives the external identifier corresponding to the terminal device from the UDM network element.

[0324] The external identifier of the terminal device corresponds to the first signed data.

[0325] Step 1006: The NEF network element sends the external identifier corresponding to the terminal device to the AF network element. Correspondingly, the AF network element receives the external identifier corresponding to the terminal device from the NEF network element.

[0326] Step 1007: The AF network element sends a ninth request message to the NEF network element. Correspondingly, the NEF network element receives the ninth request message from the AF network element.

[0327] Among them, the ninth subscription request message is used to request the subscription of session-related events of the first contract data, and the session-related events of the first contract data are the events corresponding to the services in the AF network element.

[0328] Step 1008: The NEF network element sends a first request message to the first AMF network element. Correspondingly, the first AMF network element receives the first request message from the first AMF network element.

[0329] The first request message is used to request the subscription of session-related events of the first subscription data, and the session-related events of the first subscription data are the events corresponding to the services in the AF network element.

[0330] It is understandable that steps 1007 and 1008 are similar. Step 1007 is when the AF network element initiates a request to the NEF network element, and step 1008 is when the NEF network element initiates a request to the first AMF network element.

[0331] Optionally, in step 1009, the NEF network element sends a subscription request message to the first AMF network element. Correspondingly, the first AMF network element receives the subscription request message from the NEF network element.

[0332] The subscription request message is used to request a session switching event from the terminal device.

[0333] In one possible implementation, in step 1005, while the UDM network element sends the external identifier corresponding to the terminal device to the NEF network element, the UDM network element also sends first indication information to the NEF network element. The first indication information indicates that the terminal device has dual-connectivity capabilities, meaning that a session handover event may occur. Based on the first indication information, the NEF network element sends a subscription request message to the first AMF network element.

[0334] Step 1010: A session switching event occurs on the terminal device.

[0335] As an example, the terminal device switches the session from the first subscription data to the second subscription data.

[0336] In this case, the address information of the terminal device remains unchanged, and the AF network element is unaware of the session handover event.

[0337] Step 1011: The first AMF network element sends a notification message to the NEF network element. Correspondingly, the NEF network element receives the notification message from the first AMF network element.

[0338] The notification message is used to indicate that a session switching event has occurred.

[0339] It is worth noting that in this embodiment, the NEF network element may not send a subscription request message to the first AMF network element, that is, step 1009 may not be executed. Optionally, when the session corresponding to the first subscription data needs to perform a session switch, the first AMF network element actively sends a notification message to the NEF network element to indicate that a session switch event has occurred.

[0340] Optionally, in step 1012, the NEF network element sends a request message to the UPF network element. Correspondingly, the UPF network element receives the request message from the NEF network element.

[0341] The request message is used to request the identification information of the terminal device. The request message includes the terminal device's address information (UE IP). It is understandable that after a session handover event occurs, the NEF network element requests the terminal device's identification information again.

[0342] Optionally, in step 1013, the UPF network element sends a second feedback message to the NEF network element. Correspondingly, the NEF network element receives the second feedback message from the UPF network element.

[0343] The second feedback message includes the identification information of the terminal device.

[0344] It is worth noting that in step 1011, the first AMF network element can send the identifier corresponding to the second subscription data to the NEF network element at the same time as sending the notification message. In this case, steps 1012 to 1013 do not need to be executed.

[0345] Step 1014: The NEF network element sends a fourth request message to the UDM network element. Correspondingly, the UDM network element receives the fourth request message from the NEF network element.

[0346] The fourth request message is used to request an update to the mapping relationship of the external identifier corresponding to the terminal device.

[0347] As an example, the mapping between the external identifier corresponding to the terminal device and the identifier of the first contract data is updated to the mapping between the external identifier corresponding to the terminal device and the identifier of the second contract data, that is, the external identifier corresponding to the terminal device corresponds to the second contract data.

[0348] Step 1015: The UDM network element sends an acknowledgment message to the NEF network element. Correspondingly, the NEF network element receives the acknowledgment message from the UDM network element.

[0349] The confirmation message is used to provide feedback on the mapping relationship between the external identifier of the updated terminal device and the signed data.

[0350] As an example, the UDM network element indicates that the external identifier corresponding to the NEF network element terminal device corresponds to the second contract data.

[0351] Step 1016: The NEF network element sends a second request message to the second AMF network element. Correspondingly, the second AMF network element receives the second request message from the NEF network element.

[0352] The second request message is used to request session-related events for the second contract data. The session-related events for the second contract data are the events corresponding to the services in the AF network element after the session switch.

[0353] In the embodiment shown in Figure 10, the UDM network element does not change the mapping relationship of the external identifier corresponding to the terminal device. Instead, after the session switching event of the terminal device is completed, the NEF network element triggers the UDM network element to update the mapping relationship of the external identifier corresponding to the terminal device and re-triggers the event subscription.

[0354] As shown in Figure 11, Figure 11 is a schematic diagram illustrating a specific implementation of another communication method provided in this application embodiment. The difference between this embodiment and the embodiment shown in Figure 10 is that, after a session switching event occurs on the terminal device, the AF network element re-triggers the mapping of the terminal device's external identifier and re-triggers the event subscription. The specific method includes:

[0355] Steps 1101 to 1106 are the same as steps 1001 to 1006 in the above embodiments, and will not be repeated here.

[0356] Step 1107: The AF network element sends a fifth request message to the NEF network element. Correspondingly, the NEF network element receives the fifth request message from the AF network element.

[0357] The fifth request message is used to request the event corresponding to the service, and to request the subscription session switching event.

[0358] As an example, the fifth request message includes an external identifier corresponding to the terminal device.

[0359] In one possible implementation, in step 1105, when the UDM network element sends the mapping relationship of the external identifier corresponding to the terminal device to the NEF network element, the UDM network element also sends indication information to the NEF network element. This indication information indicates whether the terminal device has dual-connectivity capabilities, i.e., whether the terminal device can perform session switching. In step 1106, based on the terminal device's dual-connectivity capabilities, the NEF network element indicates to the AF network element that the terminal device can perform session switching, and then the AF sends a fifth request message to the NEF network element.

[0360] Step 1108: The NEF network element sends a first request message to the first AMF network element. Correspondingly, the first AMF network element receives the first request message from the NEF network element.

[0361] The first request message is used to request the time corresponding to the service and to request the subscription session switching event.

[0362] As an example, the first request message includes an external identifier corresponding to the terminal device.

[0363] It is understandable that step 1108 is similar to step 1107. Step 1107 is when the AF network element initiates a request to the NEF network element, and step 1108 is when the NEF network element initiates a request to the first AMF network element.

[0364] Optionally, step 1109 involves the terminal device executing a session switching event.

[0365] As an example, the terminal device switches the session from the first subscription data to the second subscription data.

[0366] Step 1110: The first AMF network element determines that a session handover event has occurred and sends a notification message to the NEF network element. Correspondingly, the NEF network element receives the notification message from the first AMF network element.

[0367] The notification message is used to indicate that a session switching event has occurred.

[0368] Step 1111: The NEF network element sends a notification message to the AF network element. Correspondingly, the AF network element receives the notification message from the NEF network element.

[0369] The notification message is used to indicate that a session switching event has occurred.

[0370] Because of the session switching event, the mapping relationship between the external identifier of the terminal device and the identifier of the subscription data changes, that is, the session switches from the first subscription data to the second subscription data. Therefore, the AF network element needs to reacquire the external identifier corresponding to the terminal device.

[0371] Steps 1112 to 1117 are the same as steps 1101 to 1106 above, except that in step 1112, the AF network element sends a sixth request message to the NEF network element. Correspondingly, the NEF network element receives the sixth request message from the AF network element. The external identifier corresponding to the terminal device corresponds to the identifier of the second subscription data.

[0372] Steps 1118 and 1119 are the same as steps 1107 and 1108 above, except that in step 1118, the AF network element sends a seventh request message to the NEF network element. Correspondingly, the NEF network element receives the seventh request message from the AF network element. The session on the first subscription data is switched to the second subscription data; therefore, in step 1119, the NEF network element sends a second request message to the second AMF network element.

[0373] In the embodiment shown in Figure 11, when the AF network element subscribes to session-related events for the first subscribed data, it adds subscription to session switching events, enabling the AF network element to detect the occurrence of session switching events in the terminal device. When a session switching event occurs, the AF network element re-triggers the subscription process, that is, the AF network element subscribes to session-related events for the second subscribed data.

[0374] The above mainly describes the solutions of the embodiments of this application from the perspective of interaction between various network elements. It is understood that each network element, such as a terminal or network device, includes corresponding structures and / or software modules to perform the above functions in order to achieve them. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0375] This application embodiment can divide functional units according to the terminal device and network device described above. For example, each function can be divided into separate functional units, or two or more functions can be integrated into one processing unit. The integrated unit can be implemented in hardware or as a software functional unit. It should be noted that the unit division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0376] The method of the embodiments of this application has been described above with reference to Figure 8. The communication apparatus for executing the above method provided in the embodiments of this application is described below. Those skilled in the art will understand that the methods and apparatus can be combined with and referenced in each other, and the communication apparatus provided in the embodiments of this application can execute the steps performed by the NEF network element in the above analysis method.

[0377] When using an integrated unit, FIG12 shows the communication device involved in the above embodiment, which may include: a communication module 1201 and a processing module 1202.

[0378] In an alternative implementation, the communication device 120 may further include a storage module 1203 for storing the program code and data of the communication device.

[0379] On one hand, the communication device 120 is a NEF network element, or a chip applied in a NEF network element. In this case, the communication module 1201 is used to support communication between the communication device and an external network element (e.g., a first network element). For example, the communication module 1201 is used to perform signal transmission and reception operations of the NEF network element in the above method embodiment. The processing module 1202 is used to perform signal processing operations of the NEF network element in the above method embodiment.

[0380] In one example, communication module 1201 is used to perform the receiving action performed by the NEF network element in step 803 of FIG8 of the above embodiment. Communication module 1201 is also used to perform the transmitting actions performed by the NEF network element in steps 802 and 804 of FIG8 of the above embodiment.

[0381] In one possible embodiment, the processing module 1202 is used to perform the processing action performed by the NEF network element in step 801 of FIG8 of the above embodiment.

[0382] On the other hand, the communication device 120 is a first network element, or a chip applied in a first network element. In this case, the communication module 1201 is used to support communication between the communication device and external network elements (e.g., NEF network elements). For example, the communication module 1201 is used to perform signal transmission and reception operations of the first network element in the above method embodiment. The processing module 1202 is used to perform signal processing operations of the first network element in the above method embodiment.

[0383] In one example, the communication module 1201 is used to perform the transmitting action performed by the first network element in step 803 of FIG8 of the above embodiment. The communication module 1201 is also used to perform the receiving actions performed by the first network element in steps 802 and 804 of FIG8 of the above embodiment.

[0384] The processing module 1202 can be a processor or controller, such as a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor can also be a combination that implements computational functions, such as a combination of one or more microprocessors, a combination of a digital signal processor and a microprocessor, etc. The communication module can be a transceiver, transceiver circuitry, or communication interface, etc. The storage module can be a memory.

[0385] When the processing module 1202 is a processor 1301 or a processor 1305, the communication module 1201 is a transceiver 1303, and the storage module 1203 is a memory 1302, the communication device involved in this application can be the communication device shown in FIG13.

[0386] Figure 13 shows a schematic diagram of the hardware structure of a communication device provided in an embodiment of this application. The hardware structure of the terminal device and network device in this embodiment can be referred to the structure shown in Figure 13. The communication device includes a processor 1301, a communication line 1304, and at least one transceiver (Figure 13 is only an example illustrating the inclusion of transceiver 1303).

[0387] The processor 1301 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits used to control the execution of the program of the present application.

[0388] Communication line 1304 may include a path for transmitting information between the aforementioned components.

[0389] Transceiver 1303 is a device that uses any transceiver-like device to communicate with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area network (WLAN), etc.

[0390] Optionally, the communication device may also include a memory 1302.

[0391] The memory 1302 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto. The memory 1302 may exist independently and be connected to the processor 1301 via communication line 1304. The memory 1302 may also be integrated with the processor 1301.

[0392] The memory 1302 stores computer execution instructions for implementing the scheme of this application, and the processor 1301 controls the execution. The processor 1301 executes the computer execution instructions stored in the memory 1302, thereby implementing the communication method provided in the following embodiments of this application.

[0393] Optionally, the computer execution instructions in the embodiments of this application may also be referred to as application code, and the embodiments of this application do not specifically limit this.

[0394] In a specific implementation, as one embodiment, processor 1301 may include one or more CPUs, such as CPU0 and CPU1 in FIG13.

[0395] In a specific implementation, as one example, the communication device may include multiple processors, such as processor 1301 and processor 1302 in FIG. 13. Each of these processors may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. Here, a processor may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0396] Figure 14 is a schematic diagram of the structure of chip 140 provided in an embodiment of this application. Chip 140 includes one or more (including two) processors 1410 and communication interfaces 1430.

[0397] Optionally, the chip 140 also includes a memory 1440, which may include read-only memory and random access memory, and provides operation instructions and data to the processor 1410. A portion of the memory 1440 may also include non-volatile random access memory (NVRAM).

[0398] In some implementations, memory 1440 stores elements such as execution modules or data structures, or subsets thereof, or extended sets thereof.

[0399] In this embodiment of the application, the corresponding operation is executed by calling the operation instructions stored in the memory 1440 (the operation instructions can be stored in the operating system).

[0400] One possible implementation is that the terminal and network devices have similar structures, and different devices can use different chips to achieve their respective functions.

[0401] The processor 1410 controls the processing operations of any terminal or network device. The processor 1410 can also be referred to as a central processing unit (CPU).

[0402] Memory 1440 may include read-only memory and random access memory, and provides instructions and data to processor 1410. A portion of memory 1440 may also include NVRAM. For example, in an application, memory 1440, communication interface 1430, and memory 1440 are coupled together via bus system 1420, which may include, in addition to data bus, power bus, control bus, and status signal bus, etc. However, for clarity, all buses are labeled as bus system 1420 in Figure 14.

[0403] The methods disclosed in the embodiments of this application can be applied to or implemented by the processor 1410. The processor 1410 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the integrated logic circuit of the hardware in the processor 1410 or by instructions in the form of software. The processor 1410 may be a general-purpose processor, a digital signal processor (DSP), an ASIC, a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software modules may be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory 1440. Processor 1410 reads the information in memory 1440 and, in conjunction with its hardware, completes the steps of the above method.

[0404] In one possible implementation, the communication interface 1430 is used to perform the receiving and transmitting steps of the NEF network element in the embodiment shown in FIG8. The processor 1410 is used to perform the processing steps of the NEF network element in the embodiment shown in FIG8.

[0405] The communication module described above can be a communication interface of the device, used to receive signals from other devices. For example, when the device is implemented as a chip, the communication module is the communication interface used by the chip to receive or send signals from other chips or devices.

[0406] On the one hand, a computer-readable storage medium is provided, which stores instructions that, when executed, implement the functions performed by the NEF network element as shown in Figure 8.

[0407] On the one hand, a computer-readable storage medium is provided, which stores instructions that, when executed, implement the function performed by the first network element as shown in Figure 8.

[0408] On the one hand, a computer-readable storage medium is provided, which stores instructions that, when executed, implement the function performed by the second network element as shown in Figure 8.

[0409] On the one hand, a computer program product including instructions is provided. When the instructions are executed, the functions performed by the NEF network element as shown in Figure 8 are realized.

[0410] On the one hand, a computer program product including instructions is provided. When the instructions are executed, the functions performed by the first network element as shown in Figure 8 are realized.

[0411] On the one hand, a computer program product including instructions is provided. When the instructions are executed, the functions performed by the second network element as shown in Figure 8 are realized.

[0412] On the one hand, a chip is provided that is used in a computing network controller. The chip includes at least one processor and a communication interface. The communication interface and at least one processor are coupled together. The processor is used to run instructions to implement the functions performed by the NEF network element as shown in Figure 8.

[0413] On the one hand, a chip is provided that is used in a network manager. The chip includes at least one processor and a communication interface. The communication interface and at least one processor are coupled together. The processor is used to run instructions to implement the functions executed by the first network element as shown in Figure 8.

[0414] On the one hand, a chip is provided that is used in a network manager. The chip includes at least one processor and a communication interface. The communication interface and at least one processor are coupled together. The processor is used to run instructions to implement the functions executed by the second network element as shown in Figure 8.

[0415] The explanations and beneficial effects of the relevant content in any of the communication devices provided above can be found in the corresponding method embodiments provided above, and will not be repeated here.

[0416] In this embodiment, the terminal device or network device includes a hardware layer, an operating system layer running on top of the hardware layer, and an application layer running on top of the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and memory (also called main memory). The operating system can be any one or more computer operating systems that implement business processing through processes, such as Linux, Unix, Android, iOS, or Windows. The application layer includes applications such as browsers, address books, word processing software, and instant messaging software. Furthermore, this embodiment does not specifically limit the specific structure of the execution entity of the method provided in this embodiment, as long as it can communicate according to the method provided in this embodiment by running a program that records the code of the method provided in this embodiment. For example, the execution entity of the method provided in this embodiment can be a terminal device or a network device, or a functional module in the terminal device or network device that can call and execute a program.

[0417] Furthermore, various aspects or features of this application can be implemented as methods, apparatus, or articles of manufacture using standard programming and / or engineering techniques. The term "article of manufacture" as used herein encompasses a computer program accessible from any computer-readable device, carrier, or medium. For example, computer-readable media may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks, or magnetic tapes), optical discs (e.g., compact discs (CDs), digital versatile discs (DVDs), etc.), smart cards, and flash memory devices (e.g., erasable programmable read-only memory (EPROMs), cards, sticks, or key drives, etc.). Additionally, the various storage media described herein may represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing, and / or carrying instructions and / or data.

[0418] It should be understood that the processor mentioned in the embodiments of this application can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0419] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDR SDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchlink DRAM (SLDRAM), and Direct Rambus RAM (DR RAM).

[0420] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) is integrated into the processor.

[0421] It should be noted that the memories described herein are intended to include, but are not limited to, these and any other suitable types of memories.

[0422] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0423] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0424] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0425] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0426] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0427] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0428] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, characterized in that, The method includes: Obtain the mapping relationship between the first identifier of the terminal device and the identifier of the signed data; Send a first request message to the first network element. The first request message is used to subscribe to events related to the session of the first contract data. The first identifier is associated with the identifier of the first contract data. The first contract data belongs to the contract data. Receive first information from the first network element, the first information being used to indicate that a handover event has occurred in the terminal device, the handover event indicating that the terminal device’s session has switched from the first subscription data to the second subscription data; Send a second request message to the second network element. The second request message is used to subscribe to events related to the session of the second subscribed data.

2. The method according to claim 1, characterized in that, The events related to the session of the second contract data are the same as those related to the session of the first contract data.

3. The method according to claim 1 or 2, characterized in that, The method further includes: A subscription request message is sent to the first network element, the subscription request message being used to subscribe to the handover event of the terminal device.

4. The method according to claim 1, characterized in that, The process of obtaining the correspondence between the first identifier of the terminal device and the identifier of the signed data includes: Send a third request message to a third network element, the third request message being used to request information from the first identifier; The system receives information about the first identifier from the third network element. The information about the first identifier includes the first identifier, the identifier of the first contract data associated with the first identifier, and the identifier of the second contract data.

5. The method according to any one of claims 1 to 3, characterized in that, The first identifier is associated with the identifier of the first contract data. After receiving the first information from the first network element, the method further includes: Send a fourth request message to the third network element, the fourth request message being used to request an update to the mapping relationship; The updated mapping relationship is received from the third network element, and the updated mapping relationship includes the association between the first identifier and the identifier of the second contract data.

6. The method according to any one of claims 1 to 3, characterized in that, The first identifier is associated with the identifier of the first contract data. After obtaining the mapping relationship between the first identifier of the terminal device and the identifier of the contract data, the method further includes: A fifth request message is received from the fourth network element. The fifth request message is used to subscribe to events related to the session of the first contracted data and to subscribe to the switching event.

7. The method according to claim 6, characterized in that, After receiving the first information from the first network element, the method further includes: Send the first information to the fourth network element; Receive a sixth request message from the fourth network element, the sixth request message being used to instruct the acquisition of a second identifier, the second identifier being associated with the identifier of the second contract data; Obtain the second identifier; Send the second identifier to the fourth network element; The system receives a seventh request message from the fourth network element. The seventh request message is used to subscribe to session-related events of the second subscription data and to subscribe to the handover event.

8. The method according to any one of claims 1 to 7, characterized in that, The first contract data and the second contract data belong to the same user of the same operator.

9. The method according to any one of claims 1 to 8, characterized in that, The first request message is also used to subscribe to session-related events of the second contracted data.

10. A communication method, characterized in that, The method includes: Receive a third request message from a network exposure function network element, the third request message including the identifier of the first subscription data, the third request message being used to request the third network element to provide the identifier of the terminal device; Send information of a first identifier to the network exposure function element. The information of the first identifier includes the first identifier and the identifier of the subscription data associated with the first identifier.

11. The method according to claim 10, characterized in that, The information of the first identifier includes: the first identifier of the terminal device, and the identifier of the first contract data and the identifier of the second contract data associated with the first identifier.

12. The method according to claim 10 or 11, characterized in that, The method further includes: Send indication information to the network exposure function network element, the indication information being used to indicate that the terminal device is a dual-connection device.

13. The method according to any one of claims 10 to 12, characterized in that, The first contract data and the second contract data belong to the same user of the same operator.

14. A communication method, characterized in that, The method includes: Receive a first request message from a network exposure function element, wherein the first request message is used to subscribe to session-related events of the first subscription data; When the session of the terminal device switches from the first subscription data to the second subscription data, a first message is sent to the network exposure function element. The first message indicates a switching event of the terminal device, and the switching event indicates that the session of the terminal device switches from the first subscription data to the second subscription data.

15. The method according to claim 14, characterized in that, The method further includes: Receive a subscription request message from the network exposure function element, the subscription request message being used to subscribe to the handover event.

16. The method according to claim 14, characterized in that, The first request message is also used to subscribe to the handover event that occurs on the terminal device.

17. A communication method, characterized in that, The method includes: Send an eighth request message to the network exposure function network element. The eighth request message is used to request the acquisition of the terminal device identifier. The terminal device identifier is used by the network exposure function network element to obtain the mapping relationship between the first identifier of the terminal device and the identifier of the subscription data. Receive information from the network exposure function element regarding the first identifier, wherein the information of the first identifier includes the first identifier and an identifier of the subscription data associated with the first identifier; A ninth request message is sent to the network exposure function element, the ninth request message being used to request subscription to events related to the session of the first subscribed data.

18. The method according to claim 17, characterized in that, The information of the first identifier includes: the first identifier, the identifier of the first contract data, and the identifier of the second contract data.

19. The method according to claim 17, characterized in that, The information of the first identifier includes: the first identifier and the identifier of the first contract data.

20. The method according to claim 19, characterized in that, The ninth request message is also used to subscribe to a switching event, and the method further includes: Receive first information from the network exposure function element, the first information being used to instruct the terminal device to perform the handover event, the handover event instructing the terminal device's session to switch from the first subscription data to the second subscription data; A sixth request message is sent to the network exposure function element, the sixth request message being used to instruct the acquisition of the correspondence between the second identifier and the identifier of the second contract data; Receive information from the network exposure function element regarding the second identifier, wherein the information of the second identifier includes the second identifier and the identifier of the second subscription data; A seventh request message is sent to the network exposure function element. The seventh request message is used to subscribe to session-related events of the second subscription data and to subscribe to the handover event.

21. A communication device, characterized in that, The apparatus includes a module for performing the method as described in any one of claims 1 to 20.

22. A communication device, characterized in that, The communication device includes a memory and a processor. The memory is used to store instructions, and the processor is used to execute the instructions stored in the memory. Execution of the instructions stored in the memory causes the processor to perform the method of any one of claims 1 to 9; or, perform the method of any one of claims 10 to 13; or, perform the method of any one of claims 14 to 16; or, perform the method of any one of claims 17 to 20.

23. A chip, characterized in that, The chip includes at least one processor and a communication interface, the communication interface being coupled to the at least one processor, the at least one processor being configured to run a computer program or instructions to implement the method as described in any one of claims 1 to 9; or, to implement the method as described in any one of claims 10 to 13; or, to implement the method as described in any one of claims 14 to 16; or, to implement the method as described in any one of claims 17 to 20, wherein the communication interface is configured to communicate with other modules outside the chip.

24. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when executed, implement the method described in any one of claims 1 to 9; or, implement the method described in any one of claims 10 to 13; or, implement the method described in any one of claims 14 to 16; or, implement the method described in any one of claims 17 to 20.

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