RU2772780C2 - Communication method, device and system - Google Patents

Abstract

FIELD: communication technologies.

SUBSTANCE: invention relates to the field of communication technologies, and more specifically to a method, device and communication system. The effect is achieved in that the communication method includes: receiving by the network element of the access and mobility control function in the first public land mobile network a registration request message from the terminal device; and upon determining that the first condition is met, sending the configured network segment selection assistance information of the first public land mobile network to the terminal device. The first condition includes one of the following: the registration request message is an initial registration request message, or the registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network.

EFFECT: ensuring that the network device sends the updated configured network segment selection assistance information to the terminal device while conserving network resources.

65 cl, 20 dwg, 1 tbl

Description

[0001] The present application claims priority based on Chinese Patent Application No. CN 201810483383.0, filed with the National Intellectual Property Office of China on May 18, 2018, entitled "COMMUNICATION METHOD, APPARATUS, AND SYSTEM", which claims the priority of Chinese Patent Application No. CN 201810313059.4, filed with the National Intellectual Property Administration of China on April 9, 2018, entitled "COMMUNICATION METHOD, APPARATUS, AND SYSTEM", which are hereby incorporated by reference in their entirety.

Technical field

[0002] This application relates to the field of communication technologies, and more specifically to a method, device and communication system.

State of the art

[0003] With the development of technology, more and more devices access the mobile network. Application scenarios for different devices may vary. Different types of application scenarios have different network function and network performance requirements. The convergence and optimization of traditional human-centric single networks can no longer meet the requirements. In addition, optimization and requirements can vary greatly in different network scenarios. For example, in some scenarios, it is necessary to provide a service with ultra-low latency and high reliability; some other scenarios require a service with many connections but relatively little data; while other scenarios require a service with high bandwidth and large data volume. If a dedicated network is built for each scenario, the cost to build and operate the network increases for the operator, resulting in an inefficient waste of resources. Hence, the concept of network segmentation arises.

[0004] Network segmentation may allow an operator to provide, in the same network infrastructure, in an independent virtual logical network manner, different types of application scenarios with mutually isolated network environments, so that network functions and features can be configured for various types of application scenarios depending on their respective requirements, and the requirements of various services can be effectively met.

[0005] When a network segment is deployed in the core network, the terminal device stores a configured Network Slice Selection Assistance Information (Configured NSSAI) portion of each Public Land Mobile Network (PLMN). When a terminal device registers on the network, the network segment selection process starts. For example, the terminal device generates the requested network segment selection assistance information (requested by NSSAI) based on the configured network segment selection assistance information of a certain PLMN with which the terminal device requests registration or has registered, and sends the requested network segment selection assistance information to the network device. The network device returns the allowed network segment selection assistance information (Requested NSSAI) to the terminal device. The Radio Access Network (RAN) device accessed by the terminal device can perform the network segment selection procedure using the allowed network segment selection assistance information.

[0006] The configured network segment selection assistance information for the PLMN may be updated, or this configured network segment selection assistance information stored by the terminal device is different from the configured network segment selection assistance information of the public land mobile network in which the terminal device resides. However, in some scenarios, the network device may not send the updated configured network segment selection assistance information to the terminal device. In this case, the network segment corresponding to the requested network segment selection assistance information determined by the terminal device may not be compatible with the network slice that can be provided by the network device. Therefore, the terminal device may not request a network segment that is initially available, which reduces the user experience; or the terminal device may request use of an unavailable network segment, wasting signaling communication. Therefore, how to ensure that the network device can send the updated configured network segment selection assistance information to the terminal device is an urgent task.

The essence of the invention

[0007] This application provides a communication method, device, and system.

[0008] According to a first aspect, this application provides a communication method including: receiving, by a network element of an access and mobility control function in a first public land mobile network, a registration request message from a terminal device; and upon determining that the first condition is met, sending the configured network segment selection assistance information of the first public land mobile network to the terminal device. The first condition includes one of the following: the registration request message is an initial registration request message or the registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network.

[0009] According to this method, for a scenario in which the signed S-NSSAI of a terminal device is changed when the terminal device is in a deregistered state (RM-DEREGISTERED), or for a scenario in which a signed S-NSSAI included in the subscription information of the terminal device , changes when the terminal device moves from the second PLMN to the first PLMN and is based on the second PLMN, the method can be used to ensure that the configured NSSAI of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience (efficiency) with the terminal device and save network resources.

[0010] In an exemplary embodiment, the first condition further includes: the access and mobility control function network element obtains terminal device subscription information from the unified data management network element. Therefore, it is possible to prevent the AMF from resending the configured network segment selection assistance information of the first PLMN to the terminal device when the terminal device re-registers with the AMF within a short time, thereby further avoiding unnecessary network signaling overhead and saving network resources.

[0011] According to a second aspect, this application provides a communication method, including: receiving, by means of a unified management network element, data from a first network element of an access and mobility control function in a first public terrestrial mobile communication network, a request for obtaining subscription information of a terminal device, where the first access and mobility control network element is an access and mobility control network element that serves the terminal device; sending by the unified administration network element the subscription information of the terminal device to the first network element of the access and mobility control function, where the subscription information of the terminal device includes at least sub-subscription information of the network segment selection of the terminal device; and causing, by the unified data administration network element, the first network element of the access and mobility control function to update the first configured network segment selection assistance information, wherein the first configured network segment selection assistance information is the configured network segment selection assistance information with which the terminal device requests registration. .

[0012] According to the method, for a scenario in which a signed S-NSSAI of a terminal device is changed when the terminal device is in a deregistration state (RM-DEREGISTERED), or for a scenario in which a signed S-NSSAI included in the subscription information of the terminal device , changes when the terminal device moves from the second PLMN to the first PLMN and bases on the second PLMN, this method can be used to ensure that the configured NSSAI of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience with the terminal device and saving network resources.

[0013] In an exemplary embodiment, instructing, by the unified data management network element, the first access and mobility management function network element to update the first configured network segment selection assistance information includes: sending, by the unified data management network element, the first indication information to the first function network element access and mobility control, where the first indication information is used to instruct the first network element of the access and mobility control function to update the first configured network segment selection assistance information; or sending, by the unified data management network element, a terminal device subscription modification notification message to the first network element of the access and mobility control function, where the terminal device subscription modification notification message includes the terminal device network segment selection signed auxiliary information.

[0014] In an exemplary embodiment, the method further includes: sending, by the unified administration network element, subscription request data to a first access and mobility management function network element, where the subscription request is used to request the first access and mobility control network element to send a notification message to the unified data management network element after the update of the first configured network segment selection auxiliary information is completed; and receiving, by means of the unified data administration network element, the notification message from the first network element of the access and mobility control function. Therefore, it can be ensured that the PLMN ID maintained by the UDM is the same as the actual result of updating the configured network segment selection assistance information for the PLMN of the terminal device.

[0015] In an exemplary embodiment, after the Unified Data Management Network Element instructs the first Access and Mobility Management Function Network Element to update the first configured Network Segment Selection Assistance Information, the Unified Data Management Element determines that updating the first configured Network Segment Selection Assistance Information does not need to initiate; or after the unified data manager receives the notification message from the first network element of the access and mobility control function, the unified data manager determines that the update of the first configured network segment selection assistance information does not need to be triggered.

[0016] In an exemplary embodiment, before instructing, by the unified data management network element, the first access and mobility management function network element to update the first configured network segment selection assistance information, the method further includes: determining, by the unified data management network element, that the configured network segment selection assistance information of one or more public land mobile networks of the terminal is to be updated, the one or more public land mobile networks including the first public land mobile network. For example, when determining that the subscription information of the terminal device changes, the unified data management network element determines that the configured network segment selection assistance information of one or more terminal's terrestrial mobile public networks needs to be updated.

[0017] According to a third aspect, this application provides a communication method including: sending, by a first network element, an access and mobility control function in a first public land mobile network, to a unified administration network element, request data to obtain subscription information of a terminal device, where the first network element the access and mobility control function element is a network element of the access and mobility control function that serves the terminal device; receiving, by the first network element of the access and mobility management function, the subscription information of the terminal device from the unified data administration network element, where the subscription information of the terminal device includes at least signed auxiliary network segment selection information of the terminal device; and initiating, by the first network element of the access and mobility control function, updating the first configured network segment selection assistance information according to the indication of the unified data management network element, where the first configured network segment selection assistance information is the configured network segment selection assistance information, with which the terminal device requests registration.

[0018] According to the method, for a scenario in which the signed S-NSSAI of the terminal device is changed when the terminal device is in the deregistration state (RM-DEREGISTERED), or for a scenario in which the signed S-NSSAI included in the subscription information of the terminal device is changed when the terminal device moves from the second PLMN to the first PLMN and bases on the second PLMN, the method can be used to ensure that the configured NSSAI of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0019] In an exemplary embodiment, initiating by the first network element of the access and mobility control function to update the first configured network segment selection assistance information in accordance with the indication of the unified data management network element includes: upon receiving the first indication information from the unified data management network element, initiating, by the first network element of the access and mobility control function, updating the first configured network segment selection assistance information based on the signed network segment selection assistance information; or upon receiving the terminal device subscription modification notification message from the unified data management network element, initiating, by the first network element of the access and mobility control function, updating the first configured network segment selection assistance information based on the signed network segment selection assistance information of the terminal device included in the message terminal device subscription modification notifications.

[0020] In an exemplary embodiment, the method includes: receiving by the first access and mobility management function network element a subscription request from the unified data administration network element, where the subscription request is used to request the first access and mobility management function network element to send a notification message to the unified network element administering the data upon completion of updating the first configured sub-information of network segment selection; and upon receiving the configuration update complete message from the terminal device, sending the first network element of the access and mobility management function a notification message to the unified data network element, where the configuration update complete message is used to indicate that the terminal device has completed updating the first configured network segment selection assistance information. . Therefore, it can be ensured that the PLMN ID maintained by the UDM matches the actual result of updating the configured network segment selection assistance information for the PLMN of the terminal device.

[0021] According to a fourth aspect, this application provides a communication method, including: obtaining, by a network element of the access and mobility control function, a signed network segment selection assistance information of a terminal device; obtaining the first configured network segment selection assistance information of the terminal device, where the first configured network segment selection assistance information is the configured network segment selection assistance information of the first public land mobile network in which the terminal device requests registration; determining, based on the signed sub-information of the network segment selection, whether to update the first configured sub-information of the selection of the network segment; and if the network element of the access and mobility control function determines that it is necessary to update the first configured network segment selection assistance information, determining the second configured network segment selection assistance information based on the signed network segment selection assistance information, and sending the second configured network segment selection assistance information to the terminal device. .

[0022] In an exemplary embodiment, receiving by the access and mobility management network element the first configured network segment selection assistance information of the terminal device includes: receiving by the access and mobility management network element a registration request message from the terminal device, where the registration request message includes the first the configured network segment selection auxiliary information. For example, the registration request message is an initial registration request message, or the registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network. Alternatively, the network element of the access and mobility control function obtains a terminal device context, where the terminal device context includes the first configured network segment selection assistance information.

[0023] In a possible implementation, determining by the network element of the access and mobility control function, based on the signed network segment selection auxiliary information, whether the first configured auxiliary information of the network segment selection needs to be updated, includes: determining by the network element of the access and mobility control function whether the first configured network segment selection assistance information is the same as the signed network segment selection assistance information, and if the first configured network segment selection assistance information is different from the signed network segment selection assistance information, determining that the first configured network segment selection assistance information must be updated to the second configured network segment selection auxiliary information, where the one network segment selection auxiliary information included in o a second configured network segment selection assistance information, the same as the signed network segment selection assistance information.

[0024] In an exemplary embodiment, the first configured network segment selection assistance information is the configured network segment selection assistance information of the visited public terrestrial public network of the terminal device, and determination, by the network element, of the access and mobility control function based on the signed network segment selection assistance information, is necessary whether to update the first configured network segment selection assistance information, includes: determining, by the network element, an access and mobility control function based on the first configured network segment selection assistance information, a signed network segment selection assistance information, and a mapping relationship between the first configured network segment selection assistance information segment and the configured assistance information for selecting the network segment of the home terrestrial network about of the general use of the terminal device whether it is necessary to update the first configured network segment selection auxiliary information.

[0025] In an exemplary embodiment, the method further includes: storing, by the network element of the access and mobility control function, the second configured network segment selection assistance information in the context of the terminal device. Thus, when a terminal device registers with another AMF, the other AMF can directly obtain the second configured network segment selection assistance information from the context of the terminal device.

[0026] According to a fifth aspect, this application provides a communication method including: sending a registration request message by a terminal device to a network element of an access and mobility control function, where the registration request message includes a first configured network segment selection auxiliary information of the terminal device, and the first the configured network segment selection assistance information is the configured network segment selection assistance information of the public land mobile network with which the terminal device requests registration; and obtaining second configured network segment selection assistance information for the first public land mobile network.

[0027] According to the method, for a scenario in which the signed S-NSSAI of a terminal device is changed when the terminal device is in a deregistered state (RM-DEREGISTERED), or for a scenario in which a signed S-NSSAI included in the subscription information of the terminal device , changes when the terminal device moves from the second PLMN to the first PLMN and bases on the second PLMN, this method can be used to ensure that the configured NSSAI of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience with the terminal device and saving network resources.

[0028] In an exemplary embodiment, the registration request message is an initial registration request message, or a registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network.

[0029] According to a sixth aspect, this application provides a communication method, including: receiving, by a terminal device, an updated user equipment route selection policy; determining that the transmission of update indication information to the network element of the access and mobility control function is not recorded; sending update indication information to the network element of the access and mobility control function, where the update indication information is used to direct the network element of the access and mobility control function to send the updated configured network segment selection assistance information to the terminal device, and the network element of the access and mobility control function is located in the visited public land mobile network; and a record that update indication information has been sent to the visited PLMN.

[0030] According to the method, for a scenario in which a signed S-NSSAI of a terminal device is changed when the terminal device is in a deregistration state (RM-DEREGISTERED), or for a scenario in which a signed S-NSSAI included in the subscription information of the terminal device , changes when the terminal device moves from the second PLMN to the first PLMN and bases on the second PLMN, this method can be used to ensure that the configured NSSAI of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience with the terminal device and saving network resources.

[0031] According to a seventh aspect, an embodiment of this application further provides a communication method, including: obtaining, by a network element of an access and mobility control function in a first network, a first configured network segment selection auxiliary information associated with the first network of a terminal device; and sending the first configured network segment selection assistance information and indication information to the terminal device, where the indication information is used to direct the terminal device to delete the second configured network segment selection assistance information associated with a different network than the first network.

[0032] Therefore, when the terminal device next registers with another network, since the terminal device does not store the configured network segment selection assistance information corresponding to the network, the terminal device does not add the requested network segment selection assistance information to the registration request. Therefore, the network side provides the terminal device with a portion of the configured network segment selection assistance information based on the current subscription information of the terminal device. Therefore, the configured network segment selection assistance information can be updated in time, thereby improving the user experience of the terminal device and saving network resources.

[0033] In an exemplary embodiment, the indication information is further used to instruct the terminal device to remove the allowed network segment selection auxiliary information associated with another network. Therefore, when the terminal device registers with another network next time, since the terminal device does not store the allowed network segment selection assistance information corresponding to the network, and the terminal device cannot determine the requested network segment selection assistance information based on the allowed network segment selection assistance information, the terminal device the device does not add the requested network segment selection assistance information to the registration request. Therefore, the network side provides the terminal device with a portion of the configured network segment selection assistance information based on the current subscription information of the terminal device. Therefore, it is further ensured that the configured network segment selection assistance information can be updated in a timely manner.

[0034] In an exemplary embodiment, obtaining by the network element of the access and mobility control function in the first network of the first configured network segment selection assistance information associated with the first network of the terminal device includes: receiving by the network element of the access and mobility control function from the administration network element data, updated signed auxiliary information of the network segment selection associated with the first network, the terminal device; and obtaining the first configured network segment selection assistance information based on the updated signed network segment selection assistance information. If the access and mobility control network element determines that the first configured network segment selection assistance information is obtained based on the updated signed network segment selection assistance information, the access and mobility control function network element sends indication information to the terminal device. In other words, the method is applicable to a scenario in which modification of the subscription data of a terminal device results in a change in the configured NSSAI of the terminal device in the current PLMN.

[0035] In an exemplary implementation, the network element sending the access and mobility management function the first configured network segment selection ancillary information and pointing information to the terminal device includes: sending, by the network element the access and mobility control function, commands to update the configuration of the user equipment to the terminal device, where the user equipment configuration update command includes the first configured network segment selection auxiliary information and indication information; or sending, by the network element of the access and mobility control function, a registration acceptance message to the terminal device, where the registration acceptance message includes the first configured network segment selection auxiliary information and indication information.

[0036] According to an eighth aspect, an embodiment of this application further provides a communication method, including: receiving, by a terminal device from a network element of an access and mobility control function in a first network, a first configured network segment selection auxiliary information corresponding to a first network, a terminal devices; deleting a second configured network segment selection assistance information associated with a different network than the first network; and replacing the stored third configured network segment selection assistance information associated with the first network with the first configured network segment selection assistance information.

[0037] Therefore, since the terminal device deletes the second configured network segment selection assistance information associated with a different network than the first network when the terminal device registers in a different network next time, because the terminal device does not store the configured network segment selection assistance information corresponding to the network, the terminal device does not add the requested network segment selection assistance information to the registration request. Therefore, the network side provides the terminal device with a portion of the configured network segment selection assistance information based on the current subscription information of the terminal device. Therefore, the configured network segment selection assistance information can be updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0038] In an exemplary embodiment, the method further includes: receiving, by the terminal device, indication information from the network element of the access and mobility control function, wherein the indication information is used to direct the terminal device to remove the second configured network segment selection assistance information.

[0039] In an exemplary embodiment, the method further includes: deleting, by the terminal device, the allowed network segment selection assistance information associated with another network. For example, the terminal device receives indication information from the network element of the access and mobility control function, where the indication information is used to direct the terminal device to remove the second configured network segment selection auxiliary information and the allowed network segment selection auxiliary information. Therefore, when the terminal device registers with another network next time, since the terminal device also does not store the allowed network segment selection sub-information corresponding to the network, and the terminal device cannot determine the requested network segment selection sub-information based on the allowed network segment selection sub-information, the terminal device does not add the requested network segment selection assistance information to the registration request. Therefore, the network side provides the terminal device with a portion of the configured network segment selection assistance information based on the current subscription information of the terminal device. Therefore, it is further ensured that the configured network segment selection assistance information can be updated in a timely manner.

[0040] According to a ninth aspect, an embodiment of this application further provides a communication device, where the communication device includes blocks configured to implement any of the first aspect or possible implementations of the first aspect, or includes blocks configured to implement any of the second aspect or possible implementations of the second aspect, or includes blocks configured to implement any of the third aspect or possible implementations of the third aspect, or includes blocks configured to implement any one of the fourth aspect or possible implementations of the fourth aspect, or includes blocks, configured to implement any of the fifth aspect or possible implementations of the fifth aspect, or includes units configured to implement any one of the sixth aspect or possible implementations of the sixth aspect, or includes units configured to implement any of the seven aspect or possible implementations of the seventh aspect, or includes blocks configured to implement any of the eighth aspect or possible implementations of the eighth aspect.

[0041] According to a tenth aspect, an embodiment of this application provides a communication device, the communication device including: a memory configured to store a program; and a processor configured to execute the program stored in the memory. When the program is executed, the processor is configured to perform a method according to any one of the first aspect or possible implementations of the first aspect, or configured to perform a method according to any one of the second aspect or possible implementations of the second aspect, or configured to perform a method according to any of the third aspect or possible implementations. of the third aspect, or configured to perform the method according to any one of the fourth aspect or possible implementations of the fourth aspect, or configured to perform the method according to any one of the fifth aspect or possible implementations of the fifth aspect, or configured to perform the method according to any one of the sixth aspect or possible implementations of the sixth aspect, or configured to perform the method according to any one of the seventh aspect or possible implementations of the seventh aspect, or configured to perform the method according to any one of the eighth aspect or possible implementations izations of the eighth aspect. Optionally, the communication device is a microchip or an integrated circuit.

[0042] According to an eleventh aspect, an embodiment of this application provides a computer-readable storage medium. The computer-readable storage medium stores the instruction. When an instruction is executed on a computer, the computer is enabled to perform the methods in accordance with the above aspects.

[0043] According to a twelfth aspect, an embodiment of this application provides a computer program product including an instruction. When the computer program product is run on the computer, the computer is enabled to perform the methods in accordance with the above aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1 - structural block diagram of the system;

[0045] FIG. 2 is a schematic flowchart of a communication method according to an embodiment of the present application;

[0046] FIG. 3 is a flowchart of another communication method according to an embodiment of the present application;

[0047] FIG. 4 is a flowchart of another communication method according to an embodiment of the present application;

[0048] FIG. 5 is a flowchart of another communication method according to an embodiment of the present application;

[0049] FIG. 6 is a flowchart of another communication method according to an embodiment of the present application;

[0050] FIG. 7 is a flowchart of another communication method according to an embodiment of the present application;

[0051] FIG. 8A to FIG. 8H is a schematic block diagram of a communication device according to an embodiment of this application;

[0052] FIG. 9 is a schematic structural diagram of a communication device according to an embodiment of this application;

[0053] FIG. 10 is a schematic block diagram of yet another communication method according to an embodiment of this application;

[0054] FIG. 11 is a schematic block diagram of yet another communication method according to an embodiment of this application;

[0055] FIG. 12 is a schematic block diagram of yet another communication method according to an embodiment of this application; as well as

[0056] FIG. 13 is a schematic block diagram of yet another communication method according to an embodiment of this application.

Description of Embodiments[0057] The technical solutions of the present application will now be described with reference to the accompanying drawings.

[0058] The technical solutions of the embodiments of this application can be applied to various communication systems, such as: Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA), General Packet Radio Service (GPRS), Long Term Evolution (LTE), Duplex LTE ( Frequency Division Duplex, FDD), LTE (Time Division Duplex, TDD), Universal Mobile Telecommunications System (UMTS), Worldwide Interoperability for Microwave Access, WiMAX ), communication system of the future 5th generation (5th ^Generation , 5G) or New Radio (NR) system.

[0059] A terminal device in embodiments of this application may also be referred to as a user equipment, an access terminal, a user equipment, a subscriber station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communications device, a user agent, a user device, etc. The terminal device may alternatively be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld a device having a wireless communication function, a computing device, another processing device connected to a wireless modem, an automobile device, a wearable device, a terminal device in the future 5G network, a terminal device in the future Public Land Mobile Network (PLMN), and etc. In embodiments of the present application, this is not limited.

[0060] When a network segment is deployed in the core network, if the user initially connects to the network, the network segment selection process is started. The network segment selection process depends on the user's subscription data, local configuration information, roaming protocol, carrier policy, and so on. In the process of selecting a network segment, the optimal type of network segment can be selected for a terminal device only taking into account all of the above parameters. To select the optimal network segment type for a terminal device, the 3rd Generation Partnership Project (3GPP) has defined several different types of Network Slice Selection Assistance information ( ^NSSAI ).

[0061] When a terminal device needs to access a particular network slice, the terminal device may provide the requested NSSAI to the core network, which is used by the core network to select a network segment instance for the terminal device. For example, the terminal device may provide the network with an NSSAI including a set of parameters for selecting a network segment instance for the terminal device. The NSSAI may be a standardized value or a specific value in the PLMN. The NSSAI may be a set of Single Network Slice Selection Assistance Information (S-NSSAI), and each part of the S-NSSAI is used to identify the type of network segment. The terminal device may store the configured NSSAI and/or the allowed NSSAI of each PLMN. The configured NSSAI is configured in the terminal device prior to interaction between the terminal device and the PLMN. The configured NSSAI is used to generate the requested NSSAI to be used by the terminal device when the terminal device initially accesses the PLMN. The network side determines the appropriate network segment type and the appropriate Access and Mobility Management Function (AMF) for the terminal device based on the requested NSSAI. In the embodiments of this application, the signed auxiliary information of the network segment selection of the terminal device is referred to as the signed S-NSSAI of the terminal device and includes one or more parts of the signed auxiliary information of the choice of one network segment (signed S-NSSAI). When the subscribed S-NSSAI of the terminal device changes, an update of the configured NSSAI of each PLMN of the terminal device may be triggered.

[0062] In order to better understand the technical solutions of this application, the system to which this application applies is first described.

[0063] FIG. 1 is a structural block diagram of the system. System 100 shown in FIG. 1 includes a terminal device 110, an Access and Mobility Management Function (AMF) network element 120, and a Unified Data Management (UDM) network element 130.

[0064] The access and mobility management function network element 120 is responsible for managing the mobility of the terminal device. For example, the mobility management function network element 120 may manage the user's roaming status and assign a temporary user ID. Moreover, the mobility management function network element 120 can authenticate and authorize the user.

[0065] The unified data administration network element 130 is responsible for managing the subscription data of the terminal device. When the subscription data is modified, the unified data administration network element 130 is responsible for notifying the corresponding network element.

[0066] The access and mobility control function and unified data administration may be implemented using said hardware, or may be implemented by a software instance on said hardware, or may be implemented using a virtual function built on a suitable platform. In this application, it is expressly not limited.

[0067] For convenience of description, in the following embodiments, AMF is an abbreviation for Access and Mobility Management Function Network Element, and UDM is an abbreviation for Unified Data Management Network Element.

[0068] In the structural block diagram of the system shown in FIG. 1 shows only the network elements in the system related to the technical solutions of this application. One of skill in the art can appreciate that the system 100 shown in FIG. 1 should further include other network elements for implementing wireless communication, such as a Radio Access Network (RAN) device and a Session Management Function (SMF) network element.

[0069] FIG. 2 is a schematic flowchart of a communication method according to an embodiment of the present application.

[0070] Step 201: The AMF in the first Public Land Mobile Network (PLMN) receives a registration request message from the terminal device.

[0071] AMF is a serving AMF of a terminal device. For example, the AMF receives a terminal device registration request message sent by the RAN device.

[0072] Step 202: Upon determining that the first condition is met, the AMF sends the configured Network Segment Selection Assistance Information (configured by NSSAI) of the first PLMN to the terminal device, where the first condition includes one of the following: The registration request message is an initial request message. registration (initial registration), or a registration request message is sent after the terminal device transitions from the second PLMN to the first PLMN.

[0073] For example, when a terminal device powers up or unregisters and then re-registers with the network, the terminal device sends an initial registration request message to the AMF to request registration with the network. For example, the initial registration request message may be a registration request message whose registration type is initial registration.

[0074] The AMF may determine, based on the 5G Globally Unique Temporary Identifier (5G GUTI) carried in the registration request message sent by the terminal device, that the terminal device is moving from the second PLMN to the first PLMN. Specifically, 5G GUTI includes Mobile Country Code (MCC) and Mobile Network Code (MNC). The MCC and MNC form the PLMN identifier. AMF can get PLMN ID from 5G GUTI. The PLMN ID is the PLMN ID for the PLMN in which the last AMF serving the terminal resides. In addition, when the terminal device moves from the second PLMN to the first PLMN, the registration type carried in the registration request message sent by the terminal device to the AMF is a mobility registration update. Therefore, the condition for sending the configured network segment selection assistance information of the first PLMN to the terminal apparatus can also be understood as follows: the registration type carried in the registration request message is a mobility registration update.

[0075] In some cases, the subscribed S-NSSAI of a terminal device may change when the terminal device is in a de-registered (RM-DEREGISTERED) state, and changing the subscribed S-NSSAI of the terminal device may change the configured NSSAI of each PLMN of the terminal device. Since the terminal device is in the de-registration state, the 5G core network cannot send the updated configured NSSAI of each PLMN to the terminal. Therefore, the configured NSSAI of each PLMN currently stored in the terminal cannot be updated in a timely manner (briefly referred to as scenario 1 below). If the method shown in Fig. 2, assuming that the registration type carried in the registration request message sent by the terminal device to the AMF in the first PLMN is the initial registration, the AMF in the first PLMN sends the configured network segment selection assistance information of the first PLMN to the terminal device. Thus, it can be ensured that when scenario 1 occurs after the terminal device registers with the first PLMN, the AMF can send the configured NSSAI of the first PLMN to the terminal device in time. Therefore, the terminal device can obtain the updated configured NSSAI of the first PLMN in time. Upon subsequent access to the first PLMN, the terminal device may determine the requested NSSAI based on the updated configured NSSAI and provide the requested NSSAI to the core network for network segment selection.

[0076] For example, a terminal device's initially subscribed S-NSSAIs include S-NSSAI 1, S-NSSAI 2, and S-NSSAI 4. Since the network segments corresponding to S-NSSAI 1, S-NSSAI 2, and S-NSSAI 3 deployed in the first PLMN, the configured NSSAIs of the terminal device in the first PLMN include S-NSSAI 1 and S-NSSAI. 2. When the subscribed S-NSSAI of the terminal device is changed, for example, the changed subscribed S-NSSAI include S-NSSAI 1, S-NSSAI 2 and S-NSSAI 3, in accordance with the solution of the prior art, the configured NSSAI of the terminal device in the first PLMNs cannot be updated in time. Therefore, the network segment corresponding to S-NSSAI 3 cannot be used. However, according to the solutions of this embodiment of this application, the configured NSSAIs of the first PLMN used by the terminal device can be updated in a timely manner. For example, the updated configured NSSAIs of the first PLMN include S-NSSAI 1, S-NSSAI 2, and S-NSSAI 3. Therefore, the terminal device can use the network segment corresponding to S-NSSAI 3, thereby improving the user experience.

[0077] As another example, the modified signed S-NSSAIs include S-NSSAI 1 and S-NSSAI 4. According to the prior art solution, configured NSSAIs of a terminal device cannot be updated in time. Therefore, the terminal device may request to use the network segment corresponding to S-NSSAI 2 in the first PLMN, and this causes network signaling to be wasted. However, according to the solutions of this embodiment of this application, the configured NSSAIs of the first PLMN used by the terminal device can be updated in a timely manner. For example, the updated configured NSSAIs of the first PLMN include S-NSSAI 1. Therefore, the terminal device does not request the use of a network segment corresponding to S-NSSAI 2, thereby avoiding unnecessary waste of network signaling and saving network resources. In some cases, the terminal device moves from the second PLMN to the first PLMN. If the subscribed S-NSSAIs included in the subscription information of the terminal device are changed while the terminal device remains in the second PLMN, changing the subscribed S-NSSAI of the terminal device may cause the configured NSSAI of each PLMN of the terminal device to change. However, since the terminal device resides in the second PLMN, the AMF only sends the configured NSSAI of the second PLMN to the terminal device, but does not send the configured NSSAI of the first PLMN of the terminal device (briefly referred to as scenario 2). If the method shown in Fig. 2, provided that the registration type of the terminal device is mobility registration update and the terminal device moves from the second PLMN to the first PLMN, the AMF may send the updated configured NSSAI of the first PLMN to the terminal device. Similarly, the method shown in FIG. 2 can be used to ensure that the configured NSSAI of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0078] Optionally, in some embodiments, the first condition further includes: The AMF obtains the terminal device's subscription information from the UDM. The UDM may be the UDM in the Home PLMN (Home PLMN, HPLMN) of the terminal device. The terminal device subscription information may include signed S-NSSAIs of the terminal device. In other words, when the above condition is met, the AMF sends the configured NSSAI of the first PLMN to the terminal device only after the AMF receives the subscription information of the terminal device from the UDM. According to the above solutions, it is possible to prevent the AMF from resending the configured network segment selection assistance information of the first PLMN to the terminal device when the terminal device repeatedly registers with the AMF in a short time, thereby further avoiding waste of network signaling and saving network resources.

[0079] That the AMF sends the configured NSSAI of the first PLMN to the terminal device, namely step 202, may include: adding the configured NSSAI of the first PLMN to the registration confirmation message by the AMF and sending the registration confirmation message to the terminal device; or sending the configured NSSAI AMF to the terminal device using a User Equipment (UE) Configuration Update Command (UE Configuration Update Command).

[0080] FIG. 3 is a flowchart of another communication method according to an embodiment of the present application.

[0081] Step 301. The UDM receives from the first AMF in the first PLMN a request to obtain terminal device subscription information, where the first AMF is an AMF that serves the terminal device.

[0082] The UDM is the UDM in the terminal device's home PLMN.

[0083] Step 302: The UDM sends the terminal device's subscription information to the first AMF, where the subscription information includes at least the terminal device's signed S-NSSAIs.

[0084] Step 303: The UDM instructs the first AMF to update the first configured network segment selection assistance information, where the first configured network segment selection assistance information is the configured network segment selection assistance information of the first PLMN of the terminal device.

[0085] Step 304: The first AMF causes the first configured network segment selection assistance information to be updated according to the UDM indication.

[0086] According to the method shown in FIG. 3, when sending the signed S-NSSAI of the terminal device to the AMF that serves the terminal device, the UDM may instruct the AMF to update the first configured network segment selection assistance information. Thus, the AMF can update the configured network segment selection assistance information according to the UDM indication.

[0087] Optionally, in some embodiments, that the UDM instructs the first AMF to update the first configured network segment selection auxiliary information includes: sending by the UDM the first indication information to the first AMF, where the first indication information is used to indicate the first AMF for updating the first configured network segment selection assistance information. In this case, when receiving the first indication information from the UDM, the first AMF initiates updating the first configured network segment selection assistance information based on the signed S-NSSAIs of the terminal device included in the subscription information of the terminal device. In the above technical solutions, the UDM instructs the first AMF to update the first configured network segment selection assistance information by explicitly instructing it. This will be further described with reference to FIG. 4. Optionally, the first indication information may be used implicitly to direct the first AMF to update the first configured network segment selection auxiliary information. For example, the first indication information is used to indicate that the subscribed S-NSSAI of the terminal device has been updated. In this case, when receiving the first indication information from the UDM, the first AMF determines, based on the subscribed S-NSSAI of the terminal device included in the subscription information of the terminal device, to update the first configured network segment selection auxiliary information. This will be further described with reference to FIG. ten.

[0088] Optionally, in some other embodiments, that the UDM instructs the first AMF to update the first configured network segment selection ancillary information includes: sending, by the UDM, a terminal device subscription modification notification message to the first AMF, where the terminal device subscription modification notification message device includes a signed S-NSSAI terminal device. In this case, upon receiving the terminal device subscription modification notification message from the UDM, the first AMF initiates an update of the first configured network segment selection assistance information based on the subscribed S-NSSAIs of the terminal device included in the terminal device subscription modification notification message. This will be further described with reference to FIG. 5.

[0089] Optionally, in some embodiments, the UDM may further send a subscription request to the first AMF, where the subscription request is used to request the first AMF to send a notification message to the UDM after the update of the first configured network segment selection assistance information is completed. After receiving the subscription request and after receiving the configuration update complete message from the terminal device, the first AMF sends a notification message to the UDM, where the configuration update complete message is used to indicate that the terminal device has completed updating the first configured network segment selection assistance information. Accordingly, the UDM may receive a notification message from the first AMF. According to the aforementioned technical solutions, the UDM can determine whether the update of the first configured network segment selection auxiliary information has been completed.

[0090] Optionally, in some embodiments, before the UDM instructs the first AMF to update the first configured network segment selection assistance information, the UDM may further determine that it is necessary to update the configured network segment selection assistance information for one or more terminal device PLMNs, where one or more PLMNs include the first PLMN. One or more PLMNs are PLMNs with which a terminal device can register. For example, when determining that the subscription information of the terminal device changes, the UDM may determine that the configured network segment selection assistance information of one or more PLMNs of the terminal device needs to be updated.

[0091] Optionally, in some embodiments, one or more PLMNs include a second PLMN. In this case, the UDM may record that it is necessary to trigger an update of the first configured network segment selection assistance information. The UDM may further record that it is necessary to trigger an update of the second configured network segment selection assistance information, where the second configured network segment selection assistance information is the configured network segment selection assistance information of the second public land mobile network of the terminal device.

[0092] Optionally, in some embodiments, after receiving from the first AMF a notification message that is used to indicate that the update of the first configured network segment selection assistance information is completed, the UDM may record that the update of the first configured network segment selection assistance information does not initiate need. Alternatively, after the UDM instructs the first AMF to update the first configured network segment selection assistance information, the UDM may record that the update of the first configured network segment selection assistance information does not need to be triggered. Therefore, the update state of the configured network segment selection assistance information of each PLMN can be accurately maintained, and network management can be optimized.

[0093] After Step 304, if the UDM again receives a request for obtaining subscription information of the terminal device from the first AMF, and the UDM determines that the configured network segment selection assistance information of the first PLMN of the terminal device does not need to be updated, the UDM does not change the record of whether whether to update the first configured sub-information of network segment selection. In this case, the UDM may instruct the first AMF not to update the first configured network segment selection ancillary information. The UDM may instruct the first AMF explicitly not to update the first configured hop selection ancillary information. For example, the UDM may send the second indication information to the first AMF, where the second indication information is used to direct the first AMF not to update the first configured network segment selection auxiliary information. Alternatively, the UDM may instruct, in an implicit manner, the first AMF not to update the first configured network segment selection assistance information. For example, the UDM does not send to the first AMF information (eg, first indication information or a terminal device subscription modification notification message) that is used to direct the first AMF to update the first configured network segment selection auxiliary information.

[0094] FIG. 4 is a flowchart of another communication method according to an embodiment of the present application.

[0095] Step 401: The UDM determines that it is necessary to update the configured network segment selection assistance information for one or more PLMNs of the terminal device.

[0096] One or more PLMNs include a first PLMN. The UDM is the UDM in the terminal device's home PLMN.

[0097] Optionally, the UDM may determine that the subscribed S-NSSAI of the terminal device has changed and then further determine that the configured network segment selection assistance information of one or more PLMNs of the terminal device needs to be updated.

[0098] Step 402: The UDM generates a first type identifier for each of the one or more PLMNs.

[0099] For example, the first type identifier is used to indicate that the AMF in each of one or more PLMNs needs to update the configured PLMN network segment selection assistance information. For convenience of description, the first type identifier of each PLMN may be referred to as the first indication information. The first indication information is used to direct the first AMF in the first PLMN to update the first configured network segment selection auxiliary information. The first configured network segment selection auxiliary information is the configured network segment selection auxiliary information of the first PLMN of the terminal device. In other words, step 402 may be: UDM generates first indication information, wherein the first indication information is used to direct the first AMF to update the first configured network segment selection assistance information.

[0100] It is contemplated that one or more PLMNs further include a second PLMN, and the AMF in the second PLMN is the second AMF. The first type identifier of the second PLMN may be referred to as the third indication information. The third indication information is used to direct the second AMF to update the second configured network segment selection auxiliary information. The second configured network segment selection auxiliary information is the configured network segment selection auxiliary information of the second PLMN of the terminal device. The configured network segment selection assistance information of the first PLMN of the terminal device in this document is the configured network segment selection assistance information stored by the first PLMN terminal device. Similarly, the configured network segment selection assistance information of the second PLMN of the terminal device is the configured network segment selection assistance information stored by the terminal device, the second PLMN.

[0101] Step 403: The UDM records that the first type identifier is to be sent to one or more PLMNs.

[0102] The UDM may record in a variety of ways whether the first type identifier needs to be sent to one or more PLMNs.

[0103] For example, in some embodiments, the UDM supports two types of identifiers: a first type identifier and a second type identifier. For example, the UDM may store the identifier of each PLMN directly. The identifier of each PLMN is a first type identifier or a second type identifier. If the PLMN identifier is a first type identifier, the first type identifier must be sent to the AMF in said PLMN. If the PLMN identifier is a second type identifier, the second type identifier must be sent to the AMF in the PLMN. The second type identifier is used to indicate that the AMF in the PLMN does not need to update the configured PLMN network segment selection ancillary information. For example, the UDM may set different values or different flag bits for the first type identifier and the second type identifier.

[0104] For another example, in some embodiments, the UDM may support one type of identifier: a first type identifier. For example, the UDM may store the identifier of each PLMN, and the identifier of each PLMN is a first type identifier or has no identifier. If the PLMN identifier is a first type identifier, the first type identifier must be sent to the AMF in said PLMN. If the PLMN does not have an identifier, no identifier needs to be sent to the AMF in said PLMN, or a second type identifier needs to be sent to the AMF in said PLMN. The second type identifier is used to indicate that the AMF in the PLMN does not need to update the configured PLMN network segment selection ancillary information.

[0105] In another example, in some embodiments, the UDM may maintain two lists: list 1 and list 2. When determining that the first type identifier should be sent to one or more PLMNs, the UDM may store the identity information of one or more PLMNs in the list 1, where the identity information may be a PLMN identifier. When determining that the first type identifier does not need to be sent to a particular PLMN, the UDM may remove the PLMN identity information from list 1 and store the PLMN identity information in list 2.

[0106] As another example, in some embodiments, the implementation of the UDM may support one list. When determining that a first type identifier is to be sent to one or more PLMNs, the UDM may store the identity information of the one or more PLMNs in a list; or upon determining that the first type identifier does not need to be sent to a particular PLMN, the UDM may remove the PLMN identity information from the list.

[0107] In addition to the above methods of recording whether the first type identifier is to be sent to one or more PLMNs, it is possible to record in another way whether the first type identifier is to be sent to one or more PLMNs. In this embodiment of this application, a specific recording method of whether the first type identifier is to be sent to one or more PLMNs is not limited.

[0108] Step 404: The terminal device generates a Requested Network Segment Selection Assistance Information (Requested NSSAI) based on the configured Network Segment Selection Assistance Information, and when registering with a particular PLMN, sends a Registration Request message that carries the requested Network Segment Selection Assistance Information.

[0109] For example, the terminal device can store the configured network segment selection assistance information of at least one PLMN, and the configured network segment selection assistance information that is used to generate the requested network segment selection assistance information is configured with the network segment selection assistance information for the PLMN. , with which the terminal device should register.

[0110] Optionally, in some embodiments, the requested network segment selection assistance information may be a subset of the configured network segment selection assistance information. In some other embodiments, the requested network segment selection assistance information may be the same as the configured network segment selection assistance information.

[0111] For example, the terminal device sends a registration request message to the RAN device, and the RAN device selects an appropriate AMF.

[0112] Step 405: The first AMF obtains the requested network segment selection assistance information.

[0113] The first PLMN is the PLMN in which the terminal device applies for registration. The first AMF is the serving AMF of the terminal device. For example, the first AMF may be an AMF selected by the RAN device, or the RAN device selects a second AMF, and after receiving a registration request message, the second AMF forwards the registration request message to the first AMF, which may serve the terminal device.

[0114] Step 406. The first AMF sends a request to the UDM to obtain the subscription information of the terminal device.

[0115] For example, the first AMF may send a request to the UDM to call the terminal device's subscription information retrieval service.

[0116] Step 407. The UDM determines, based on the recorded information, that the first AMF needs to update the first configured network segment selection assistance information.

[0117] For example, in steps 401 to 403, the UDM determines that it is necessary to update the configured network segment selection assistance information of the first PLMN of the terminal device. In this case, the UDM records that the first type identifier (namely, the first indication information) is to be sent to the first PLMN.

[0118] Step 408: The UDM sends the first indication information and subscription information of the terminal device to the first AMF. The subscription information of the terminal device includes the subscribed S-NSSAI of the terminal device.

[0119] For example, after calling the service of obtaining subscription information of the terminal device, the UDM returns the subscription information of the terminal device to the first AMF. In addition, the UDM sends the first indication information to the first AMF.

[0120] Step 409: The UDM records that the AMF in the first PLMN does not need to update the first configured network segment selection assistance information.

[0121] As described above, in some embodiments, the UDM may support two types of identifiers: a first type identifier and a second type identifier. When determining that the AMF in the first PLMN does not need to update the configured network segment selection assistance information, the UDM may modify the identifier of the first PLMN to an identifier of the second type. Thus, the UDM records that the AMF in the first PLMN does not need to update the first configured network segment selection assistance information.

[0122] For another example, in some embodiments, the UDM may support one type of identifier: a first type identifier. When determining that the AMF in the first PLMN does not need to update the first configured network segment selection ancillary information, the UDM may erase the identifier of the first PLMN. Thus, the UDM records that the AMF in the first PLMN does not need to update the first configured network segment selection assistance information.

[0123] As another example, in some embodiments, the UDM may maintain two lists: list 1 and list 2. When determining that the AMF in the first PLMN does not need to update the first configured network segment selection auxiliary information, the UDM may remove the identity information of the first PLMN from list 1 and store the identity information of the first PLMN in the list. 2. Thus, the UDM records that the AMF in the first PLMN does not need to update the first configured network segment selection assistance information.

[0124] As another example, in some embodiments, the implementation of the UDM may support one list. When determining that the AMF in the first PLMN does not need to update the first configured network segment selection ancillary information, the UDM may remove the identity information of the first PLMN from list 1. Thus, the UDM records that the AMF in the first PLMN does not need to update the first configured selection ancillary information. network segment.

[0125] Optionally, in some embodiments, provided that the UDM sends the first indication information and the subscription information of the terminal device to the first AMF, the UDM may record that the AMF in the first PLMN does not need to update the first configured network segment selection assistance information.

[0126] Optionally, in some embodiments, prior to UDM step 409, it is additionally necessary to receive a notification message that is sent by the first AMF and is used to indicate that the update of the first configured network segment selection assistance information has been completed. In other words, the UDM records, only after determining that the update of the first configured network segment selection assistance information has been completed, that the AMF in the first PLMN does not need to update the first configured network segment selection assistance information. If the UDM has not received the notification message, step 409 is not performed. Thus, it can be ensured that the PLMN ID maintained by the UDM matches the actual result of updating the configured network segment selection assistance information for the PLMN of the terminal device.

[0127] In addition, optionally, in some embodiments, the UDM may send a subscription request to the first AMF, where the subscription request is used to request the first AMF to send a notification message to the UDM after updating the first configured network segment selection assistance information is completed. In other words, the UDM may instruct, by sending a subscription request, the first AMF, whether or not to send a notification message to the UDM. Optionally, in some other embodiments, the first AMF may send a notification message to the UDM by default upon completion of updating the first configured hop selection assistance information. In other words, the first AMF sends to the UDM, without having to receive a subscription request from the UDM, a notification message that is used to indicate that the update of the first configured network segment selection assistance information has been completed.

[0128] It is assumed that after step 409, the terminal device is turned on after turning off the power, or the terminal device moves and then registers with another AMF in the first PLMN, or the terminal device moves to another PLMN and then returns to the first PLMN. It is assumed that in the above process, the signed S-NSSAI of the terminal device is not updated. In other words, in the above process, the UDM entry for the first PLMN is not changed (that is, the AMF in the first PLMN does not need to update the first configured network segment selection assistance information). In this case, after receiving a request that is for obtaining subscription information and which is sent by the first AMF or another AMF in the first PLMN, the UDM determines that the first AMF or another AMF in the first PLMN is not required to update the first configured hop selection assistance information. Thus, the UDM may instruct the first AMF or the other AMF in the first PLMN not to update the first configured network segment selection auxiliary information, or the UDM does not send the indication information to the first AMF or the other AMF in the first PLMN, which is used to indicate whether to update the first configured auxiliary information of the selection of the network segment.

[0129] It is assumed that after step 409, the terminal device switches from the first PLMN to the second PLMN. In addition, it is assumed that the second AMF becomes an AMF that serves the terminal device. It is assumed that in the above process, the record of the second PLMN maintained by the UDM is not changed (ie, it remains necessary for the AMF of the second PLMN to update the second configured network segment selection assistance information). In this case, after receiving a request that is for obtaining subscription information and which is sent by the second AMF, the UDM determines that the second AMF needs to update the second configured hop selection assistance information. Thus, the UDM may instruct the second AMF to update the second configured network segment selection assistance information.

[0130] According to the above technical solutions, the UDM can determine based on the record whether the indication information that is used to instruct the AMF in the PLMN to update the first configured network segment selection auxiliary information should be sent to the AMF.

[0131] It can be understood that in the method shown in FIG. 4, steps 401 to step 403 may be performed only when the UDM determines that it is necessary to update the configured auxiliary information of the PLMN network segment selection of the terminal device.

[0132] That the first AMF initiates an update of the first configured network segment selection assistance information may include the following steps: updating the configured network segment selection assistance information for the first PLMN of the terminal device by the AMF based on the terminal device's signed S-NSSAIs, and sending the updated NSSAI configured first PLMN to the terminal device. For example, the first AMF updates the configured network segment selection assistance information of the first PLMN of the terminal device based on the subscribed S-NSSAI of the terminal device and the S-NSSAI corresponding to the network segment supported by the first PLMN. For example, the first AMF determines a set of intersections of signed S-NSSAI and S-NSSAI corresponding to a network segment supported by the first PLMN, or a subset of intersections set as the configured network segment selection assistance information of the first PLMN of the terminal device to perform the update.

[0133] The AMF adds the first PLMN's updated configured NSSAI to the registration accept message and sends the registration accept message to the terminal device, or the AMF sends the first PLMN's updated configured NSSAI to the terminal device using a UE Configuration Update Command.

[0134] In addition, before the AMF updates the configured network segment selection assistance information of the terminal device's first PLMN based on the terminal device's signed S-NSSAIs, the AMF may again determine whether to initiate an update. For this, refer to the description of FIG. 6. Details are not described here. The signed S-NSSAI of the terminal device here are the signed S-NSSAI of the terminal device included in the subscription information of the terminal device at step 408.

[0135] After the update is completed, the terminal device may send a notification to the first AMF. The notification message is used to indicate that the terminal device has completed updating the first configured network segment selection assistance information.

[0136] Optionally, in some embodiments, the notification message that is sent by the first AMF to the UDM and is used to indicate that the update of the first configured network segment selection assistance information has been completed may be the same as the notification message received by the first AMF from the terminal. devices. In other words, the first AMF may transparently send a notification message to the UDM.

[0137] Optionally, in some other embodiments, after receiving a notification message from a terminal device, the first AMF may determine a notification message that is used to indicate that the update of the first configured network segment selection assistance information has been completed. The content indicated by the notification message specified by the first AMF may be the same as indicated by the notification message received by the first AMF, but the specific message lengths or specific forms may differ. For example, the notification message sent by the terminal device to the first AMF may be an explicit notification message, and the notification message sent by the first AMF to the UDM may be an implicit notification message.

[0138] In the method shown in FIG. 4, when receiving from the first AMF a request for obtaining the subscription information of the terminal device, the UDM determines, based on the stored ID, whether the first AMF needs to update the first configured network segment selection assistance information. Optionally, in some other embodiments, when an AMF is registered as an AMF that serves a terminal device, the UDM may determine based on the entry whether the AMF needs to be instructed to update the corresponding configured network segment selection assistance information. For example, the first AMF registers with the UDM as the AMF that serves the terminal device. In this case, the UDM determines, based on the entry, that the first AMF needs to be instructed to update the first configured network segment selection assistance information, and performs subsequent steps.

[0139] FIG. 5 is a flowchart of another communication method according to an embodiment of the present application.

[0140] Step 501: When determining that the subscribed S-NSSAI of the terminal device is changed, the UDM determines that a terminal device subscription modification notification message should be sent to one or more PLMNs.

[0141] One or more PLMNs include a first PLMN. The UDM is the UDM in the terminal device's home PLMN.

[0142] Step 502: The UDM records that a terminal device subscription modification notification message is to be sent to one or more PLMNs. The terminal device subscription modification notification message includes the signed S-NSSAI of the terminal device.

[0143] The UDM may record in a variety of ways whether a terminal device subscription modification notification message should be sent to one or more PLMNs.

[0144] For example, in some embodiments, the UDM may support two types of identifiers: a first type identifier and a second type identifier. The identifier of each PLMN is a first or second type identifier. If the PLMN identifier is a first type identifier, a terminal device subscription modification notification message should be sent to the AMF in said PLMN. If the PLMN identifier is a second type identifier, the terminal device subscription change notification message does not need to be sent to the AMF in that PLMN. When determining that a terminal device subscription modification notification message needs to be sent to one or more PLMNs, the UDM may generate a first type identifier for each of the one or more PLMNs. For convenience of description, the first type identifier of the first PLMN may be referred to as the first indication information. It is contemplated that one or more PLMNs further include a second PLMN. The UDM stores a first type identifier for each of the one or more PLMNs.

[0145] For another example, in some embodiments, the UDM may support one type of identifier: a first type identifier. The ID of each PLMN is a first type ID. If the PLMN identifier is a first type identifier, a terminal device subscription modification notification message should be sent to the AMF in that PLMN. If the PLMN does not have an ID, the terminal device subscription change notification message does not need to be sent to the AMF in that PLMN. When determining that a terminal device subscription modification notification message needs to be sent to one or more PLMNs, the UDM may generate a first type identifier for each of the one or more PLMNs. For convenience of description, the first type identifier of the first PLMN may be referred to as the first indication information. It is contemplated that one or more PLMNs further include a second PLMN. The UDM stores a first type identifier for each of the one or more PLMNs.

[0146] In the above two embodiments, the first indication information is used to record that a terminal device subscription modification notification message is to be sent to the AMF in the first PLMN. In other words, step 502 may be: UDM generates first indication information. The first indication information is used to record that a terminal device subscription modification notification message is to be sent to the AMF in the first PLMN.

[0147] In another example, in some embodiments, the UDM may maintain two lists: list 1 and list 2. When determining that a terminal device subscription modification notification message is to be sent to one or more PLMNs, the UDM may store the identity information of one or multiple PLMNs in list 1, where the identity information may be a PLMN identifier. When determining that the terminal device subscription modification notification message does not need to be sent to a particular PLMN, the UDM may remove the PLMN identity from list 1 and keep the PLMN identity in list 2.

[0148] As another example, in some embodiments, the implementation of the UDM may support one list. When determining that a terminal device subscription modification notification message is to be sent to one or more PLMNs, the UDM may store the identity information of one or more PLMNs in a list. When determining that the terminal device subscription modification notification message does not need to be sent to a particular PLMN, the UDM may remove the PLMN identity information from the list.

[0149] In addition to the above recording methods, whether a terminal device subscription modification notification message needs to be sent to one or more PLMNs, whether a terminal device subscription modification notification message can be sent to one or more PLMNs is recorded in another way. In this embodiment, this application is not limited to a particular recording method of whether a terminal device subscription modification notification message is to be sent to one or more PLMNs.

[0150] Steps 503 to 505 are similar to steps 404 to 406, and details are not described here again.

[0151] Step 506: The UDM determines, based on the recorded information, that a terminal device subscription modification notification message needs to be sent to the first AMF.

[0152] For example, in step 501 and step 502, the UDM determines that a terminal device subscription modification notification message should be sent to the AMF in the first PLMN.

[0153] Step 507: The UDM sends a terminal device subscription modification notification message to the first AMF.

[0154] Step 508: The UDM records that the terminal device subscription modification notification message does not need to be sent to the first PLMN.

[0155] The UDM may record in a variety of ways that a terminal device subscription modification notification message does not need to be sent to the first PLMN.

[0156] As described above, in some embodiments, the UDM may support two types of identifiers: a first type identifier and a second type identifier. When determining that the terminal device subscription modification notification message does not need to be sent to the first PLMN, the UDM may change the identifier of the first PLMN to an identifier of the second type. Thus, the UDM records that the terminal device subscription modification notification message does not need to be sent to the first PLMN.

[0157] For another example, in some embodiments, the UDM may support one type of identifier: a first type identifier. When determining that the terminal device subscription modification notification message does not need to be sent to the first PLMN, the UDM may erase the identity of the first PLMN. Thus, the UDM records that the terminal device subscription modification notification message does not need to be sent to the first PLMN.

[0158] As another example, in some embodiments, the UDM may maintain two lists: list 1 and list 2. When determining that the terminal device subscription modification notification message does not need to be sent to the first PLMN, the UDM may remove the identity of the first PLMN from the list. 1 and store the identification information of the first PLMN in list 2. Thus, the UDM records that the terminal device subscription modification notification message does not need to be sent to the first PLMN.

[0159] As another example, in some embodiments, the implementation of the UDM may support one list. When determining that the terminal device subscription modification notification message does not need to be sent to the first PLMN, the UDM may remove the identity information of the first PLMN from list 1. Thus, the UDM records that the terminal device subscription modification notification message does not need to be sent to the first PLMN.

[0160] Optionally, in some embodiments, provided that the UDM sends a terminal device subscription modification notification message to the first AMF, the UDM may record that the terminal device subscription modification notification message does not need to be sent to the first PLMN.

[0161] Optionally, in some other embodiments, prior to UDM step 508, it is additionally necessary to receive a notification message that is sent by the first AMF and is used to indicate that the first AMF has completed updating the configured assistance information for selecting the network segment of the first PLMN of the terminal device. In other words, the UDM records, only after determining that the AMF has completed updating the configured network segment selection assistance information of the first PLMN of the terminal device, that the terminal device subscription modification notification message should not be sent to the first PLMN. If the UDM has not received the notification message, step 508 is not performed. Thus, it can be ensured that the PLMN ID maintained by the UDM matches the actual result of updating the configured network segment selection assistance information for the PLMN of the terminal device.

[0162] In addition, optionally, in some embodiments, the UDM may send a subscription request to the first AMF, where the subscription request is used to request the first AMF to send a notification message to the UDM after updating the configured network segment selection assistance information of the first PLMN of the terminal device. In other words, the UDM may instruct, by sending a subscription request, the first AMF to send or not send a notification message to the UDM. Optionally, in some other embodiments, the first AMF may send a notification message to the UDM by default upon completion of updating the configured network segment selection assistance information of the terminal device's first PLMN. In other words, the first AMF sends to the UDM, without having to receive a subscription request from the UDM, a notification message that is used to indicate that the update of the configured network segment selection assistance information of the first PLMN of the terminal device has been completed.

[0163] It is assumed that after step 508, the terminal device is turned on after power off, or the terminal device moves and then registers with another AMF in the first PLMN, or the terminal device moves to another PLMN and then returns to the first PLMN. It is assumed that in the above process, the signed S-NSSAI of the terminal device is not updated. In other words, in the above process, the UDM entry for the first PLMN is not changed (ie, it remains unnecessary to send a terminal device subscription modification notification message to the first PLMN). In this case, after receiving a request that is for obtaining subscription information and which is sent by the first AMF or another AMF in the first PLMN, the UDM determines that the terminal device subscription modification notification message does not need to be sent to the first AMF or another AMF in the first PLMN. It is assumed that after step 508 the terminal device switches from the first PLMN to the second PLMN. In addition, it is assumed that the second AMF becomes an AMF that serves the terminal device, where the second AMF is the AMF in the second PLMN. It is assumed that in the above process, the UDM entry for the second PLMN is not changed (ie, it remains necessary to send a terminal device subscription modification notification message to the second PLMN). In this case, after receiving a request that is for obtaining subscription information and which is sent by the second AMF, the UDM determines that the terminal device subscription modification notification message should be sent to the second AMF. Thus, the UDM may send a terminal device subscription modification notification message to the second AMF.

[0164] According to the above technical solutions, the UDM can determine based on the entry whether to send a terminal device subscription modification notification message to the AMF in this PLMN.

[0165] It can be understood that in the method shown in FIG. 5, step 501 and step 502 may be performed only when the UDM determines that the subscribed S-NSSAI of the terminal device is changed.

[0166] In the above solutions, after receiving the terminal device subscription modification notification message from the UDM, the first AMF initiates an update of the configured network segment selection assistance information of the first PLMN of the terminal device.

[0167] For how the first AMF initiates updating of the configured network segment selection assistance information of the first PLMN of the terminal device, see the description of FIG. 4. Details are not described here again. Difference from Fig. 5 is that the signed terminal device S-NSSAIs herein are the signed terminal device S-NSSAIs included in the terminal device subscription modification notification message in step 507.

[0168] After the update is completed, the terminal device may send a notification message to the first AMF. The notification message is used to indicate that the terminal device has completed updating the first configured network segment selection assistance information.

[0169] Optionally, in some embodiments, the notification message that is sent by the first AMF to the UDM and is used to indicate that the update of the first configured network segment selection assistance information has been completed may be the same as the notification message received by the first AMF from the terminal. devices. In other words, the first AMF may transparently send a notification message to the UDM.

[0170] Optionally, in some other embodiments, after receiving a notification message from a terminal device, the first AMF may determine a notification message that is used to indicate that the update of the first configured network segment selection assistance information has been completed. The content indicated by the notification message specified by the first AMF may be the same as indicated by the notification message received by the first AMF, but the specific message lengths or specific forms may differ. For example, the notification message sent by the terminal device to the first AMF may be an explicit notification message, and the notification message sent by the first AMF to the UDM may be an implicit notification message.

[0171] In the method shown in FIG. 5, upon receiving the terminal device subscription information acquisition request from the first AMF, the UDM determines based on the entry whether to send a terminal device subscription modification notification message to the first AMF. Optionally, in some other embodiments, when an AMF is registered as an AMF that serves a terminal device, the UDM may determine based on the entry whether to send a terminal device subscription modification notification message to the AMF. For example, the first AMF registers with the UDM as the AMF that serves the terminal device. In this case, the UDM determines, based on the entry, that a terminal device subscription modification notification message should be sent to the first AMF, and performs subsequent steps.

[0172] FIG. 6 is a flowchart of another communication method according to an embodiment of the present application.

[0173] Step 601: The AMF obtains the signed S-NSSAI of the terminal device.

[0174] An AMF is an AMF serving a terminal device, namely a serving AMF.

[0175] Optionally, in some embodiments, the AMF may receive signed terminal device S-NSSAIs from the UDM.

[0176] Optionally, in some other embodiments, an AMF may receive signed terminal device S-NSSAIs from another AMF.

[0177] Step 602: The AMF obtains the first configured auxiliary network segment selection information of the terminal device.

[0178] The first configured network segment selection assistance information is the configured network segment selection assistance information for the PLMN with which the terminal device requests registration, and the PLMN with which the terminal device requests registration is the PLMN in which the AMF resides.

[0179] Optionally, in some embodiments, the registration request message sent by the terminal device to the AMF carries the first configured network segment selection auxiliary information, and the AMF receives the first configured network segment selection auxiliary information from the terminal device.

[0180] Optionally, in some other embodiments, the terminal device may add, only during initial registration, the first configured network segment selection assistance information to the registration request message sent to the AMF. In this case, the registration type included in the registration request message is the initial registration. In other words, the registration request message includes the first configured network segment selection auxiliary information of the terminal apparatus only when the registration type in the registration request message is an initial registration. In this case, the AMF obtains the first configured network segment selection assistance information from the initial registration request message sent by the terminal device.

[0181] Optionally, in some other embodiments, the terminal device may add, only during initial registration or PLMN handover, the first configured network segment selection assistance information to the registration request message sent to the AMF. In this case, during the initial registration, the registration type included in the registration request message is the initial registration. The PLMN switch triggers a mobility registration update. In this case, the registration type included in the registration request message sent by the terminal device is a mobility registration update. In other words, the registration request message includes the first configured network segment selection assistance information of the terminal apparatus only when the registration type in the registration request message is a mobility registration update.

[0182] Optionally, in some other embodiments, the AMF may obtain the first configured network segment selection assistance information from the terminal device context. In this case, the AMF obtains the terminal device context and obtains the first configured network segment selection assistance information from the context. According to the technical solutions, the terminal device does not need to add the first configured network segment selection assistance information to the registration request message, thereby reducing some signaling overhead. The first PLMN is the PLMN in which the terminal device requests registration. AMF is the AMF in the first PLMN.

[0183] Optionally, in some other embodiments, the AMF may send a request message for the configured network segment selection assistance information to the terminal device, where the request message for the configured network segment selection assistance information is used to request the terminal device to send the first configured network segment selection assistance information for AMF. For example, after the terminal device sends a registration request, the AMF may send a request message for the configured network segment selection assistance information to the terminal device; or after the terminal device sends an initial registration request, the AMF may send a request message for the configured network segment selection assistance information to the terminal device; or when determining that the terminal device switches from the second PLMN to the first PLMN, the AMF sends a request message for the configured network segment selection assistance information to the terminal device.

[0184] Step 603: The AMF determines, based on the terminal device's signed S-NSSAIs, whether to update the first configured network segment selection assistance information.

[0185] Step 604: If the AMF determines that it is necessary to trigger the update of the first configured network segment selection assistance information, the AMF determines the second configured network segment selection assistance information based on the signed S-NSSAIs and sends the second configured network segment selection assistance information to the terminal device.

[0186] Optionally, in some embodiments, the AMF may determine if the first configured network segment selection assistance information matches the signed S-NSSAI of the terminal device; and if the first configured network segment selection assistance information is different from the signed S-NSSAI, the AMF determines that the first configured network segment selection assistance information needs to be updated. For example, the first PLMN is the HPLMN of the terminal device, and the AMF determines, based on the subscribed S-NSSAI of the terminal device, whether one or more S-NSSAIs included in the first configured network segment selection assistance information are the same as the subscribed S-NSSAIs of the terminal device. devices; and if one or more S-NSSAIs included in the first configured Network Segment Selection Assistance Information are the same as the subscribed S-NSSAIs of the terminal device, the update of the first configured Network Segment Selection Assistance Information does not need to be triggered, or if one or more S- The NSSAIs included in the first configured network segment selection auxiliary information are different from those signed by the S-NSSAI of the terminal apparatus, it is necessary to trigger the update of the first configured network segment selection auxiliary information. In this case, the AMF may update the first configured network segment selection auxiliary information to the second configured network segment selection auxiliary information, where one or more S-NSSAIs included in the second configured network segment selection auxiliary information are the same as the signed S-NSSAIs.

[0187] Optionally, in some other embodiments, the AMF may determine, based on the first configured network segment selection assistance information, signed S-NSSAIs, a mapping relationship between the first configured network segment selection assistance information and the configured network segment selection assistance information for the public terrestrial home network terminal device whether the configured network segment selection assistance information needs to be updated. For example, the first PLMN is the VPLMN of the terminal device, and the AMF determines, based on the first configured network segment selection assistance information, signed S-NSSAIs and a mapping relationship between the first configured network segment selection assistance information and the configured network segment selection assistance information of the terminal's home public terrestrial network. device, whether to activate the update of the first configured sub-information of network segment selection. For example, the first PLMN is a visited PLMN (Visited PLMN, VPLMN) of the terminal device, and the first configured network segment selection assistance information is the configured network segment selection assistance information VPLMN of the terminal device. There may be a correspondence between the configured VPLMN network segment selection assistance information and the configured HPLMN network segment selection assistance information. For example, Table 1 shows the correspondence between the configured VPLMN network segment selection auxiliary information and the configured HPLMN network segment selection auxiliary information.

Table 1

Configured Network Segment Selection Auxiliary Information for VPLMN Configured Network Segment Selection Auxiliary Information for HPLMN S-NSSAI 1, S-NSSAI 2 S-NSSAI 11 S-NSSAI 3 S-NSSAI 21 S-NSSAI 4 S-NSSAI 31

[0188] As shown in Table 1, S-NSSAI 1 and S-NSSAI 2 in the configured VPLMN Network Segment Selection Assistance Information correspond to S-NSSAI 11 in the configured HPLMN Network Segment Selection Assistance Information; S-NSSAI 3 in the configured VPLMN network segment selection auxiliary information corresponds to S-NSSAI 21 in the configured HPLMN network segment selection auxiliary information; and S-NSSAI 4 in the configured VPLMN network segment selection auxiliary information corresponds to S-NSSAI 31 in the configured HPLMN network segment selection auxiliary information. It is assumed that network segments corresponding to S-NSSAI 1, S-NSSAI 2, S-NSSAI 3 and S-NSSAI 4 are deployed in the VPLMN.

[0189] Based on the subscribed S-NSSAI of the terminal device and the mapping relationship between the first configured network segment selection assistance information and the configured network segment selection assistance information of the home public terrestrial network of the terminal device, the AMF determines the third configured network segment selection assistance information corresponding to the signed S -NSSAI of the terminal device, and determines whether the S-NSSAI corresponding to the first configured network segment selection auxiliary information is the same as the S-NSSAI corresponding to the third configured network segment selection auxiliary information; and if the S-NSSAI corresponding to the first configured network segment selection assistance information is the same as the S-NSSAI corresponding to the third configured network segment selection assistance information, determines that the update does not need to be triggered; or if the S-NSSAI corresponding to the first configured network segment selection auxiliary information is different from the S-NSSAI corresponding to the third configured network segment selection auxiliary information, determines that the update needs to be triggered.

[0190] Table 1 is used as an example. Assuming that the subscribed S-NSSAIs include S-NSSAI 11, S-NSSAI 21 and S-NSSAI 31, and that the first configured Network Segment Selection Assistance Information includes S-NSSAI 1, S-NSSAI 2, S-NSSAI 3 and S-NSSAI 4, the AMF determines that the first configured network segment selection assistance information does not need to be updated. Assuming that the subscribed S-NSSAI of the terminal device includes S-NSSAI 11, S-NSSAI 21, and S-NSSAI 31, and that the first configured network segment selection assistance information includes S-NSSAI 1, S-NSSAI 2, and S -NSSAI 3, AMF determines that the first configured network segment selection ancillary information needs to be updated. Based on the signed S-NSSAIs and the mapping relationship between the first configured network segment selection assistance information and the configured network segment selection assistance information of the terminal device's home public terrestrial network, the AMF may determine that the second configured network segment selection assistance information includes: S-NSSAI 1, S-NSSAI 2, S-NSSAI 3, and S-NSSAI 4. Optionally, in some embodiments, after determining the second configured network segment selection assistance information, the AMF may store the second configured network segment selection assistance information in the context of the terminal device, such that when the terminal device registers with another AMF, the other AMF can directly obtain the second configured network segment selection assistance information from the context of the terminal device.

[0191] FIG. 7 is a flowchart of another communication method according to an embodiment of the present application.

[0192] Step 701: The terminal device registers with the first PLMN and receives the updated User Equipment Route Selection Policy (URSP).

[0193] Step 702: The terminal device registers with the first AMF in the second PLMN, and the terminal device determines that the update indication information has not been sent to any AMF in the second PLMN.

[0194] Step 703: The terminal device sends update indication information to the first AMF, where the update indication information is used to direct the first AMF to send the updated configured network segment selection assistance information of the second PLMN to the terminal device.

[0195] Step 704: The terminal device records that update indication information has been sent to the second PLMN.

[0196] Step 705: The first AMF sends the updated configured network segment selection assistance information of the second PLMN to the terminal device.

[0197] In the above solutions, the terminal device can determine, based on the URSP update, that it is necessary to update the network segment selection assistance information for each PLMN, and when registering with the corresponding PLMN, the terminal device actively initiates, based on the determination result, updating the configured network segment selection assistance information. PLMN segment of the terminal device.

[0198] FIG. 10 is a flowchart of another communication method according to an embodiment of the present application.

[0199] The method is associated with at least the interaction between the terminal device, AMF and UDM. For example, the terminal device, AMF, and UDM may be, respectively, the terminal device 110, the access and mobility management function network element 120, and the unified data management network element 130 of FIG. 1, and details are not described here again. The terminal device and the AMF are located in the first PLMN. In other words, the first PLMN is the PLMN currently serving the terminal device. The first PLMN may be an HPLMN or a VPLMN. The UDM resides in the terminal device's HPLMN.

[0200] As shown in FIG. 10, the method includes the following steps.

[0201] Step 1001. The UDM sends the terminal device's updated Subscribed Segment Selection Assistance Information (updated Subscribed S-NSSAIs) to the AMF in the first PLMN. For example, the terminal device's updated signed S-NSSAIs are used to identify one or more network segments available to the terminal device in the first PLMN after the subscribed S-NSSAIs are updated.

[0202] For example, after updating the subscribed S-NSSAIs in the subscription data of the terminal device, the UDM may notify the AMF in the first PLMN of the updated subscribed S-NSSAI by calling the subscriber data management (SDM) notification) service (Nudm_SDM_Notification) of said UDM. In addition, the UDM may send the signed S-NSSAI and the first indication information to the AMF in the first PLMN by calling the Nudm_SDM_Get service. The first indication information is used to indicate that the subscribed S-NSSAIs have been updated. In particular, signed S-NSSAIs are updated signed S-NSSAIs.

[0203] Optionally, after receiving updated signed S-NSSAIs (or updated signed S-NSSAIs and first indication information), the AMF may return an acknowledgment message (ACK) to the UDM.

[0204] Step 1002. The AMF determines the first configured network segment selection assistance information (first configured NSSAI) associated with the first PLMN of the terminal device.

[0205] The first configured NSSAI associated with the first PLMN of the terminal device is used to identify the network segment that is configured in the first PLMN and is available to the terminal device. The functions of the second configured NSSAI and the third configured NSSAI mentioned below are the same as the functions of the first configured NSSAI, and details are not described again.

[0206] For example, after receiving the first indication information from the UDM, the AMF decides to update the configured NSSAI of the first PLMN. In other words, when the first PLMN's subscribed S-NSSAIs are updated, the AMF decides to update the first PLMN's configured NSSAI. In addition, when the first PLMN is a VPLMN, the AMF may decide to update the mapping between the NSSAI configured first PLMN and the NSSAI configured HPLMN. Alternatively, the AMF may only initiate a mapping update between the configured NSSAI of the first PLMN and the configured NSSAI HPLMN. It's not limited here.

[0207] For example, upon receiving updated signed S-NSSAIs from the UDM, the AMF may determine the first configured NSSAI of the first PLMN based on the updated signed S-NSSAIs. Alternatively, after receiving the updated signed S-NSSAI from the UDM, the AMF may obtain the first configured NSSAI from the Network Slice Selection Function (NSSF) network element. The NSSF feature includes selecting a network segment for a terminal device. Therefore, the AMF receives the first configured NSSAI associated with the first PLMN of the terminal device. Optionally, the AMF derives a match between the first configured NSSAI and the configured NSSAI HPLMN based on the received first configured NSSAI.

[0208] Step 1003: The AMF sends the first configured NSSAI (and/or the match between the first configured NSSAI and the configured NSSAI HPLMN) and the second indication information to the terminal device. The second indication information is used to direct the terminal device to remove the second configured NSSAI associated with a different network than the first PLMN.

[0209] As described above, when the subscribed S-NSSAIs of the first PLMN are updated, the AMF determines to update the configured NSSAI of the first PLMN, and further sends the second indication information to the UE in step 1003. In other words, the AMF sends the second indication information to the UE in step 1003 only then when the AMF is notified that the first PLMN's subscribed S-NSSAIs have been updated.

[0210] For example, the AMF may send a UE configuration update command to a terminal device, where the UE configuration update command includes a first configured NSSAI and second indication information; or the AMF may send a registration acceptance message (registration acceptance) to the terminal device, where the registration acceptance message includes the first configured NSSAI and the second indication information. This application is not limited. The above message can be sent by AMF to the (R)AN device, and then the (R)AN device forwards this message to the terminal device.

[0211] "Other network than the first PLMN" in this document may be a different PLMN than the first PLMN in the network range that the terminal can access.

[0212] Optionally, the second indication information is further used to direct the terminal device to remove the allowed network segment selection ancillary information (allowed NSSAI, allowed NSSAI) associated with a different network than the first PLMN. The allowed NSSAI associated with the network is used to identify the network segment that the terminal device is allowed to access in the first PLMN.

[0213] Optionally, the second indication information is further used to direct the terminal device to remove the correspondence between the second configured NSSAI associated with a different network than the first PLMN and the configured NSSAI HPLMN. Optionally, the second indication information is further used to direct the terminal device to remove the correspondence between the allowed NSSAI associated with a different network than the first PLMN and the configured NSSAI HPLMN.

[0214] Step 1004: After receiving the first configured NSSAI and the second indication information, the terminal device deletes the second configured NSSAI associated with a different network than the first PLMN; and replaces the stored third configured NSSAI associated with the first PLMN with the first configured NSSAI.

[0215] Optionally, when the second indication information is further used to direct the terminal device to delete the correspondence between the second configured NSSAI associated with a different network than the first PLMN and the configured NSSAI HPLMN, after receiving the indication information sent in step 1003, the terminal device further deletes correspondence between the second configured NSSAI and the configured NSSAI HPLMN.

[0216] Therefore, according to the above solution, when the modification of the subscription data of the terminal device causes the configured NSSAI of the terminal device in the current PLMN to change, the AMF sends the updated configured NSSAI of the current PLMN to the terminal device and instructs the terminal device to delete the previously stored configured NSSAI of the other PLMN. Thus, when the terminal device next registers with another PLMN, since the terminal device does not store the configured NSSAI corresponding to the PLMN, the terminal device does not add the Requested NSSAI to the registration request. Therefore, the network side provides the terminal device with a portion of the configured NSSAI PLMN based on the current subscription information of the terminal device. Therefore, the configured NSSAI PLMN can be updated in time, thereby improving the user experience of the terminal device and saving network resources.

[0217] Optionally, when the second indication information is further used to direct the terminal device to remove the allowed NSSAI associated with the other network, after receiving the indication information sent in step 1003, the terminal device further removes the allowed NSSAI associated with the other network. Optionally, the terminal device further removes the correspondence between the allowed NSSAI associated with a different network than the first PLMN and the configured NSSAI HPLMN.

[0218] Therefore, when the terminal device next registers with another PLMN, since the terminal device does not store the allowed NSSAI corresponding to the PLMN and the terminal device cannot determine the requested NSSAI based on the allowed NSSAI, the terminal device does not add the requested NSSAI to the registration request. Therefore, the network side provides the terminal device with a portion of the configured NSSAI PLMN based on the current subscription information of the terminal device. Therefore, it is further guaranteed that the configured NSSAI PLMN can be updated in time.

[0219] Optionally, in another implementation, the AMF may not send the second indication information in step 1003. After receiving the first configured NSSAI, the terminal device may delete, without indicating the AMF, the second configured NSSAI associated with a different network than the first PLMN; and replace the stored third configured NSSAI associated with the first PLMN with the first configured NSSAI. Optionally, the terminal device may further remove the allowed NSSAI associated with the other network. Optionally, the terminal device further removes the correspondence between the second configured NSSAI and the configured NSSAI HPLMN. Optionally, the terminal device further removes the correspondence between the allowed NSSAI associated with a different network than the first PLMN and the configured NSSAI HPLMN.

[0220] Optionally, after receiving the first configured NSSAI, the terminal device performs step 1005.

[0221] Step 1005: The terminal device sends an acknowledgment (ACK) message to the AMF.

[0222] Alternatively, the terminal device may send an ACK to the AMF after receiving the first configured NSSAI and completing the operation at step 1004.

[0223] For example, if the first configured NSSAI is sent in step 1003 using a UE configuration update command, the terminal device may send an ACK to the AMF using a UE configuration update complete message. If the first configured NSSAI is sent in step 1003 using a registration acknowledgment message, the UE may send an ACK to the AMF using a registration complete message.

[0224] Optionally, after receiving the ACK, the AMF performs step 1006.

[0225] Step 1006: After receiving the ACK, the AMF notifies the UDM of the result of updating the configured NSSAI.

[0226] For example, the AMF may notify the UDM of the configured NSSAI update result by calling the UE Configuration Update Notification (Namf_Communication_UEConfigurationUpdateNotify) service of the AMF. Optionally, step 1001 can be considered that the UDM subscribes to a service with the AMF. Upon receipt of the notification, the UDM determines that the configured NSSAI update does not need to be initiated. For example, the UDM does not update the configured NSSAI before the terminal device's signed S-NSSAIs are updated again.

[0227] For example, the AMF may notify the UDM of the result of updating the configured NSSAI by calling the event notification service (Namf_EventExposure_Notify) of the AMF. Optionally, the UDM subscribes to the service with the AMF before or after step 1001. After receiving the notification, the UDM determines that updating the configured NSSAI is not required. For example, the UDM does not update the configured NSSAI before the terminal device's signed S-NSSAIs are updated again.

[0228] As described above, the example in FIG. 10 is applicable to a configured NSSAI update triggered by a terminal device subscription modification (which is a modification of the signed S-NSSAIs in the subscription data).

[0229] In a possible implementation, the above method is further applicable to a configured NSSAI update triggered by a different condition. For example, another condition includes at least one of the following:

1. There is a configuration modification of the serving PLMN, including a local policy modification or a modification caused by a segment deployment change;

2. The terminal device does not add the requested NSSAI when sending the registration request;

3. The particular S-NSSAI in the NSSAI requested by the terminal device is not valid in the current PLMN of the terminal device; and

4. The NSSAI requested by the terminal device is not within the range of the subscribed S-NSSAI of the terminal device.

[0230] In another possible implementation, the AMF only instructs the terminal device to delete the second configured NSSAI associated with a different network than the first PLMN when the configured NSSAI update is triggered by the terminal device subscription modification, or instructs the terminal device to delete the second configured NSSAI and the allowed NSSAI, which are connected to a different network than the first PLMN.

[0231] The method of FIG. 10 is applicable to the scenario in which the terminal device is turned on after being turned off, and is also applicable to the roaming scenario. Alternatively, optionally, for a scenario in which the terminal device is turned on after being turned off, either of the methods in FIG. 2 - fig. 7 can be used; and for the roaming scenario, the method of FIG. 10 can be used.

[0232] Referring to the above description of FIG. 10, this application provides a communication method. As shown in FIG. 11, the method includes the following steps.

[0233] Step 1101: The network element of the access and mobility control function in the first network obtains the first configured network segment selection assistance information associated with the first network of the terminal device.

[0234] Step 1102. The network element of the access and mobility control function sends the first configured network segment selection auxiliary information and indication information to the terminal device, where the indication information is used to direct the terminal device to remove the second configured network segment selection auxiliary information associated with another network, than the first network.

[0235] The indication information is described in the description of the second indication information in FIG. 10. For step 1102, see the description of step 1003 in FIG. 10. Details are not described here again. For example, step 1102 includes: sending, by the network element of the access and mobility management function, a user equipment configuration update command to the terminal device, where the user equipment configuration update command includes the first configured network segment selection auxiliary information and indication information; or sending, by the network element of the access and mobility control function, a registration acceptance message to the terminal device, where the registration acceptance message includes the first configured network segment selection auxiliary information and indication information.

[0236] Therefore, when the terminal device next registers with another network, since the terminal device does not store the configured network segment selection assistance information corresponding to the network, the terminal device does not add the requested network segment selection assistance information to the registration request. Therefore, the network side provides the terminal device with a portion of the configured network segment selection assistance information based on the current subscription information of the terminal device. Therefore, the configured network segment selection assistance information can be updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0237] Optionally, the indication information is further used to direct the terminal device to delete the allowed network segment selection auxiliary information associated with the other network. Therefore, when the terminal device registers with another network next time, since the terminal device also does not store the allowed network segment selection sub-information corresponding to the network, and the terminal device cannot determine the requested network segment selection sub-information based on the allowed network segment selection sub-information, the terminal device does not add the requested network segment selection assistance information to the registration request. Therefore, the network side provides the terminal device with a portion of the configured network segment selection assistance information based on the current subscription information of the terminal device. Therefore, it is further ensured that the configured network segment selection assistance information can be updated in a timely manner.

[0238] Optionally, the network element of the access and mobility control function in the first network obtains the first configured network segment selection auxiliary information associated with the first network, the terminal device includes: receiving by the network element of the access and mobility control function from the network administration data element , updated signed S-NSSAI associated with the first network, the terminal device; and obtaining, by the network element of the access and mobility control function, the first configured network segment selection assistance information based on the updated subscribed S-NSSAIs. The access and mobility control network element determines that the first configured network segment selection assistance information is obtained based on the updated subscribed S-NSSAIs, and therefore, the access and mobility control function network element sends indication information to the terminal device. For example, refer to the description of steps 1001 and 1002 in FIG. ten.

[0239] Referring to the above description of FIG. 10, this application provides a communication method. As shown in FIG. 12, the method includes the following steps.

[0240] Step 1201. The terminal device receives from the network element of the access and mobility control functions in the first network the first configured network segment selection assistance information corresponding to the first network of the terminal device.

[0241] For step 1201, see the description of step 1003 in FIG. 10. Details are not described here again.

[0242] Step 1202. The terminal device deletes the second configured network segment selection assistance information associated with a different network than the first network, and replaces the stored third configured network segment selection assistance information associated with the first network with the first configured network segment selection assistance information. segment.

[0243] For step 1202, see the description of step 1004 in FIG. 10. Details are not described here again.

[0244] Therefore, since the terminal device deletes the second configured network segment selection assistance information associated with a different network than the first network when the terminal device registers in a different network next time, because the terminal device does not store the configured network segment selection assistance information corresponding to the network, the terminal device does not add the requested network segment selection assistance information to the registration request. Therefore, the network side provides the terminal device with a portion of the configured network segment selection assistance information based on the current subscription information of the terminal device. Therefore, the configured network segment selection assistance information can be updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0245] Optionally, the method further includes: receiving, by the terminal device, indication information from the network element of the access and mobility control function, wherein the indication information is used to direct the terminal device to remove the second configured network segment selection assistance information. For example, see the description of step 1003 in FIG. ten.

[0246] Optionally, the method further includes: deleting, by the terminal device, the allowed network segment selection assistance information associated with the other network. For example, see the description of step 1004 in FIG. 10. Therefore, when the terminal device registers with another network next time, since the terminal device also does not store the allowed network segment selection auxiliary information corresponding to the network, and the terminal device cannot determine the requested network segment selection auxiliary information based on the allowed network segment selection auxiliary information segment, the terminal device does not add the requested network segment selection auxiliary information to the registration request. Therefore, the network side provides the terminal device with a portion of the configured network segment selection assistance information based on the current subscription information of the terminal device. Therefore, it is further ensured that the configured network segment selection assistance information can be updated in a timely manner. In addition, optionally, the method includes: receiving, by the terminal device, indication information from the network element of the access and mobility control function, wherein the indication information is used to direct the terminal device to delete the second configured network segment selection auxiliary information and the allowed network segment selection auxiliary information.

[0247] FIG. 13 is a flowchart of another communication method according to an embodiment of the present application.

[0248] The method is associated with at least the interaction between the terminal device, AMF and UDM. For example, the terminal device, AMF, and UDM may be, respectively, the terminal device 110, the access and mobility management function network element 120, and the unified data management network element 130 in FIG. 1, and details are not described here again. The terminal device and the AMF are located in the first PLMN. In other words, the first PLMN is the PLMN currently serving the terminal device. The first PLMN may be an HPLMN or a VPLMN. The UDM resides in the terminal device's HPLMN.

[0249] As shown in FIG. 13, the method includes the following steps.

[0250] Step 1301. The UDM sends the terminal device's updated Subscribed Subscribed S-NSSAIs to the AMF in the first PLMN. For example, the terminal device's updated signed S-NSSAIs are used to identify one or more network segments available to the terminal device in the first PLMN after the subscribed S-NSSAIs are updated.

[0251] For example, after updating the subscribed S-NSSAIs in the subscription data of the terminal device, the UDM may notify the AMF in the first PLMN of the updated subscribed S-NSSAIs by calling the subscriber data management (SDM) notification service (Nudm_SDM_Notification) of the UDM. In addition, the UDM may send the signed S-NSSAI and the first indication information to the AMF in the first PLMN by calling the Nudm_SDM_Get service. The first indication information is used to indicate that the subscribed S-NSSAIs have been updated. In particular, signed S-NSSAIs are updated signed S-NSSAIs.

[0252] Optionally, after receiving updated signed S-NSSAIs (or updated signed S-NSSAIs and first indication information), the AMF may return an acknowledgment message to the UDM.

[0253] Step 1302: The AMF sends the second indication information to the terminal device. The second indication information is used to direct the terminal device to remove the second configured NSSAI associated with another PLMN other than the first.

[0254] In other words, the AMF sends the second indication information to the UE in step 1302 only when the AMF is notified that the subscribed S-NSSAIs of the first PLMN have been updated.

[0255] For example, the AMF may send a UE configuration update command to a terminal device, where the UE configuration update command includes second indication information; or the AMF may send a registration accept message to the terminal device, where the registration confirmation message includes the second indication information. This application is not limited. The above message can be sent by AMF to the (R)AN device, and then the (R)AN device forwards the message to the terminal device.

[0256] "Other network than the first PLMN" in this document may be another PLMN other than the first PLMN in the range of the network that the terminal can access.

[0257] Optionally, the second indication information is further used to direct the terminal device to remove the allowed network segment selection assistance information (NSSAI allowed, NSSAI allowed) associated with a different network than the first PLMN. The allowed NSSAI associated with the network is used to identify the network segment that the terminal device is allowed to access in the first PLMN.

[0258] Optionally, the second indication information is further used to direct the terminal device to remove the correspondence between the second configured NSSAI associated with a different network than the first PLMN and the configured NSSAI HPLMN. Optionally, the second indication information is further used to direct the terminal device to remove the correspondence between the allowed NSSAI associated with a different network than the first PLMN and the configured NSSAI HPLMN.

[0259] Optionally, before sending the second indication information to the terminal device, the AMF determines that the third configured NSSAI associated with the first PLMN of the terminal does not need to be updated.

[0260] Step 1303: After receiving the second indication information, the terminal device removes the second configured NSSAI associated with a different network than the first PLMN.

[0261] Optionally, when the second indication information is further used to direct the terminal device to delete the correspondence between the second configured NSSAI associated with a different network than the first PLMN and the configured NSSAI HPLMN, after receiving the indication information sent in step 1302, the terminal device further deletes correspondence between the second configured NSSAI and the configured NSSAI HPLMN.

[0262] Therefore, according to the above decision, at the time of modifying the subscription data of the terminal device, the AMF instructs the terminal device to delete the previously stored configured NSSAI of the other PLMN. Thus, when the terminal device next registers with another PLMN, since the terminal device does not store the configured NSSAI corresponding to the PLMN, the terminal device does not add the Requested NSSAI to the registration request. Therefore, the network side provides the terminal device with a portion of the configured NSSAI PLMN based on the current subscription information of the terminal device. Therefore, the configured NSSAI PLMN can be updated in time, thereby improving the user experience of the terminal device and saving network resources.

[0263] Optionally, when the second indication information is further used to direct the terminal device to remove the allowed NSSAI associated with the other network, after receiving the indication information sent in step 1302, the terminal device further removes the allowed NSSAI associated with the other network. Optionally, the terminal device further removes the correspondence between the allowed NSSAI associated with a different network than the first PLMN and the configured NSSAI HPLMN.

[0264] Therefore, when the terminal device next registers with a different PLMN, since the terminal device does not store the allowed NSSAI corresponding to the PLMN and the terminal device cannot determine the requested NSSAI based on the allowed NSSAI, the terminal device does not add the requested NSSAI to the registration request. Therefore, the network side provides the terminal device with a portion of the configured NSSAI PLMN based on the current subscription information of the terminal device. Therefore, it is further guaranteed that the configured NSSAI PLMN can be updated in time.

[0265] Optionally, after receiving the second indication information, the terminal device performs step 1304.

[0266] Step 1304: The terminal device sends an acknowledgment message to the AMF.

[0267] Alternatively, the terminal device may send an ACK to the AMF after receiving the first configured NSSAI and completing the operation at step 1303.

[0268] For example, if the second indication information is sent in step 1304 using a UE configuration update command, the terminal device may send an ACK to the AMF using a UE configuration update complete message. If the second indication information is sent in step 1302 using a registration accept message, the UE may send an ACK to the AMF using a registration complete message.

[0269] Optionally, after receiving the ACK, the AMF performs step 1305.

[0270] Step 1305: After receiving the ACK, the AMF notifies the UDM of the result of updating the configured NSSAI.

[0271] For example, the AMF may notify the UDM of the configured NSSAI update result by calling the UE Configuration Update Notification (Namf_Communication_UEConfigurationUpdateNotify) service of the AMF. Optionally, step 1301 can be considered that the UDM subscribes to the service with the AMF. Upon receipt of the notification, the UDM determines that an update of the configured NSSAI is not required. For example, the UDM does not update the configured NSSAI before the terminal device's signed S-NSSAIs are updated again.

[0272] For example, the AMF may notify the UDM of the result of updating the configured NSSAI by calling the event notification service (Namf_EventExposure_Notify) of the AMF. Optionally, the UDM subscribes to the service with the AMF before or after step 1301. After receiving the notification, the UDM determines that an update of the configured NSSAI is not required. For example, the UDM does not update the configured NSSAI before the terminal device's signed S-NSSAIs are updated again.

[0273] As described above, the example in FIG. 13 is applicable to a configured NSSAI update triggered by a terminal device subscription modification (which is a modification of the subscribed S-NSSAIs in the subscription data), and the example in FIG. 13 supports the scenario where the configured NSSAI managed by the first PLMN does not need to be updated.

[0274] In a possible implementation, the above method is further applicable to a configured NSSAI update triggered by a different condition. For example, another condition includes at least one of the following:

1. There is a configuration modification of the serving PLMN, including a local policy modification or a modification caused by a segment deployment change;

2. The terminal device does not add the requested NSSAI when sending the registration request;

3. The particular S-NSSAI in the NSSAI requested by the terminal device is not valid in the current PLMN of the terminal device; and

4. The NSSAI requested by the terminal device is not within the range of the subscribed S-NSSAI of the terminal device.

[0275] In another possible implementation, the AMF only instructs the terminal device to delete the second configured NSSAI associated with a different network than the first PLMN when the configured NSSAI update is triggered by the terminal device subscription modification, or instructs the terminal device to delete the second configured NSSAI and the allowed NSSAI, which are connected to a different network than the first PLMN.

[0276] The method of FIG. 13 is applicable to a scenario in which the terminal device de-registers and then re-registers (eg, turns on after being turned off), and is also applicable to a roaming scenario. Alternatively, and optionally, for a scenario in which the terminal device de-registers and then re-registers (eg, powered on after power off), either of the methods in FIG. 2 - fig. 7 can be used; and for the roaming scenario, the method of FIG. 13 can be used.

[0277] Therefore, with reference to the description of FIG. 13 in the manner shown in FIG. 11, in step 1102, the network element of the access and mobility control function may send only indication information to the terminal device, where the indication information is used to direct the terminal device to remove the second configured network segment selection assistance information associated with a different network than the first network. In the method shown in FIG. 12, in step 1202, the terminal device may remove the second configured network segment selection assistance information associated with a different network than the first network. Since the terminal device has not received the first configured network segment selection assistance information, the stored third configured network segment selection assistance information associated with the first network may not need to be replaced by the first configured network segment selection assistance information.

[0278] In the above embodiments presented in this application, the solutions for the communication methods provided in the embodiments of this application are separately described in terms of network elements and interaction between network elements. It can be understood that in order to implement the above functions, the network elements include an appropriate hardware structure and/or a software module to perform these functions. One skilled in the art will readily appreciate that, in combination with the examples described in the embodiments disclosed in this specification, the blocks and steps of an algorithm may be implemented in hardware or a combination of hardware and computer software in this application. The performance of a function by hardware or hardware controlled by computer software depends on particular applications and design constraints of the technical solutions. A person skilled in the art can use various methods to implement the described functions for each particular application, but such an implementation should not be considered to be outside the scope of this application.

[0279] For example, when the aforementioned network elements implement the respective functions using software modules, the communication device is located in the first public land mobile network, and as shown in FIG. 8A may include a receiving module 801, a processing module 802, and a sending module 803. The device may be a network element or an access and mobility control chip.

[0280] The device may be configured to perform the network element operations of the access and mobility control function of FIG. 2. For example, the receiving module 801 is configured to receive a registration request message from the terminal device; and the processing unit 802 is configured to: upon determining that the first condition is met, send the configured network segment selection assistance information of the first public land mobile network to the terminal device using the sending unit 803, where the first condition includes any of the following: request message registration is an initial registration request message, or a registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network.

[0281] Therefore, for a scenario in which the signed S-NSSAI of the terminal device is changed when the terminal device is in the de-registered (RM-) state, or for a scenario in which the signed S-NSSAI included in the subscription information of the terminal device is changed when the terminal device moves from the second PLMN to the first PLMN and bases in the second PLMN, the device can be used to ensure timely updating of the NSSAI configured of the first PLMN used by the terminal device, thereby improving the user experience of the terminal device and saving network resources.

[0282] Optionally, the first condition further includes: the network element of the access and mobility control function receives the subscription information of the terminal device from the unified data administration network element. Therefore, it is possible to prevent the AMF from resending the configured network segment selection assistance information of the first PLMN to the terminal device when the terminal device repeatedly registers with the AMF in a short time, thereby further avoiding unnecessary network signaling overhead and saving network resources.

[0283] As shown in FIG. 8B, another communication device may include a receiving module 811 and a sending module 812. Optionally, the communication device further includes a processing module 813. The device may be a unified data management network element or a chip.

[0284] The device may be configured to perform the UDM operations of FIG. 3, fig. 4 or FIG. 5. For example, the receiving unit 811 is configured to receive from the first access and mobility management function network element in the first public land mobile network a request to obtain terminal device subscription information, where the first access and mobility control function network element is the access control function network element and mobility, which serves the terminal device; and the sending unit 812 is configured to send the subscription information of the terminal device to the first network element of the access and mobility control function, where the subscription information of the terminal device includes at least sub-information of selecting a subscribed network segment of the terminal device; and further configured to direct the first network element of the access and mobility control function to update the first configured network segment selection assistance information, where the first configured network segment selection assistance information is configured with the network segment selection assistance information with which the terminal device requests registration.

[0285] Therefore, for the scenario in which the signed S-NSSAI of the terminal device is changed when the terminal device is in the deregistration state (RM-DEREGISTERED), or for the scenario in which the signed S-NSSAI included in the subscription information of the terminal device, changes when the terminal device moves from the second PLMN to the first PLMN and resides in the second PLMN, the device can be used to ensure that the NSSAI configured of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0286] For example, the sending module 812 is configured to send the first indication information to the first network element of the access and mobility control function, where the first indication information is used to direct the first network element of the access and mobility control function to update the first configured auxiliary network segment selection information. Alternatively, the sender 812 is configured to send a terminal device subscription modification notification message to the first network element of the access and mobility control function, where the terminal device subscription modification notification message includes signed network segment selection assistance information for the terminal device.

[0287] Optionally, the sending module 812 is further configured to send a subscription request to the first network element of the access and mobility control function, where the subscription request is used to request the first network element of the access and mobility control function to send a notification message to the unified data administration network element upon completion updating the first configured network segment selection assistance information; and the receiving module 811 is further configured to receive the notification message from the first network element of the access and mobility control function.

[0288] Optionally, the processing module 813 is configured to: after the sending module instructs the first network element of the access and mobility control function to update the first configured network segment selection assistance information, determine that the update of the first configured network segment selection assistance information does not need to be triggered. Alternatively, the processing module 813 is configured to: after the receiving module receives the notification message from the first network element of the access and mobility control function, to determine that the update of the first configured network segment selection assistance information does not need to be triggered.

[0289] Optionally, the processing module 813 is configured to: before the sending module instructs the first network element of the access and mobility control function to update the first configured network segment selection assistance information, determines that the configured network segment selection assistance information of one or more terrestrial the public mobile networks of the terminal need to be updated, wherein the one or more public land mobile networks includes the first public land mobile network. For example, the processing unit 813 is configured to: when determining that the subscription information of the terminal apparatus is changed, determining that the configured network segment selection assistance information of one or more terminal's terrestrial mobile public networks needs to be updated.

[0290] As shown in FIG. 8C, another communication device may include a sending unit 821, a receiving unit 822, and a processing unit 823. The device may be a network element or an access and mobility control chip.

[0291] The device may be configured to perform the AMF operations of FIG. 3, fig. 4 or FIG. 5. For example, the sending module 821 is configured to send a request data to the unified administration network element to obtain the subscription information of the terminal device, where the first access and mobility control network element is an access and mobility control network element serving the terminal device; the receiving unit 822 is configured to receive the terminal device subscription information from the unified data administration network element, where the terminal device subscription information includes at least signed auxiliary network segment selection information of the terminal device; and the processing unit 823 is configured to update the first configured network segment selection assistance information according to the indication of the unified data administration network element, where the first configured network segment selection assistance information is configured with the network segment selection assistance information with which the terminal device requests registration.

[0292] Therefore, for the scenario in which the signed S-NSSAI of the terminal device is changed when the terminal device is in the de-registration state (RM-DEREGISTERED), or for the scenario in which the signed S-NSSAI included in the subscription information of the terminal device, changes when the terminal device moves from the second PLMN to the first PLMN and resides in the second PLMN, the device can be used to ensure that the NSSAI configured of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0293] Optionally, the processing module 823 is configured to: when the receiving module receives the first indication information from the unified data management network element, update the first configured network segment selection information based on the signed auxiliary network segment selection information. Alternatively, the processing unit 823 is configured to: when the receiving unit receives the terminal device subscription modification notification message from the unified data management network element, update the first configured network segment selection auxiliary information based on the signed terminal device network segment selection auxiliary information included to the terminal device subscription modification notification message.

[0294] Optionally, the receiving module 822 is further configured to receive a subscription request from the unified data management network element, where the subscription request is used to request the first network element of the access and mobility control function to send a notification message to the unified data administration network element after the update of the first configured auxiliary network element is completed. network segment selection information; and after the receive module 822 receives the configuration update complete message from the terminal device, the send module 821 is further configured to send a notification message to the unified data administration network element, where the configuration update complete message is used to indicate that the terminal device has completed updating the first configured auxiliary network segment selection information.

[0295] As shown in FIG. 8D, another communication device may include an acquisition module 831 and a processing module 832. The device may be a network element or an access and mobility control chip.

[0296] The device may be configured to perform the AMF operations of FIG. 6. For example, the obtaining module 831 is configured to: obtain signed auxiliary network segment selection information of the terminal device; and obtaining the first configured network segment selection assistance information of the terminal device, where the first configured network segment selection assistance information is the configured network segment selection assistance information of the first public land mobile network in which the terminal device requests registration; and the processing unit 832 is configured to: determine, based on the signed network segment selection assistance information, whether to update the first configured network segment selection assistance information; and if it is determined that it is necessary to update the first configured network segment selection assistance information, determine the second configured network segment selection assistance information based on the signed network segment selection assistance information, and send to the terminal the second configured network segment selection assistance information to the terminal device using the sending unit.

[0297] Therefore, for the scenario in which the signed S-NSSAI of the terminal device is changed when the terminal device is in the deregistration state (RM-DEREGISTERED), or for the scenario in which the signed S-NSSAI included in the subscription information of the terminal device, changes when the terminal device moves from the second PLMN to the first PLMN and resides in the second PLMN, the device can be used to ensure that the NSSAI configured of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0298] Optionally, the acquisition module 831 is configured to receive a registration request message from the terminal device, where the registration request message includes the first configured network segment selection assistance information. The registration request message is an initial registration request message, or a registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network. Alternatively, the obtaining module 831 is configured to obtain a terminal device context, where the terminal device context includes the first configured network segment selection assistance information.

[0299] Optionally, the processing unit 832 is configured to: determine whether the first configured network segment selection auxiliary information matches the signed network segment selection auxiliary information, and if the first configured network segment selection auxiliary information is different from the signed network segment selection auxiliary information, determining that the first configured network segment selection auxiliary information is to be updated to the second configured network segment selection auxiliary information, where the unified network segment selection auxiliary information included in the second configured network segment selection auxiliary information is the same as the signed network segment selection auxiliary information segment.

[0300] Optionally, the first configured network segment selection assistance information is the configured network segment selection assistance information of the visited public terrestrial public network of the terminal device, and the processing unit 832 is configured to determine, based on the first configured network segment selection assistance information, the signed network segment selection assistance information segment, and a mapping relationship between the first configured network segment selection assistance information and the configured network segment selection assistance information of the home public terrestrial network of the terminal device, whether the first configured network segment selection assistance information should be updated.

[0301] Optionally, the processing module 832 is further configured to store the second configured network segment selection assistance information in the context of the terminal device.

[0302] As shown in FIG. 8E, another communication device may include a sending unit 841 and a receiving unit 842. The device may be a terminal device or a chip.

[0303] The device may be configured to perform the operations of the UE in FIG. 6. For example, the sending module 841 is configured to send a registration request message to the network element of the access and mobility management function, where the registration request message includes the first configured network segment selection auxiliary information of the terminal device, and the first configured network segment selection auxiliary information is the configured auxiliary information. network segment selection information for the first public land mobile network in which the terminal device requests registration; and the receiving module 842 is configured to obtain the second configured network segment selection assistance information of the first public land mobile network.

[0304] Therefore, for the scenario in which the signed S-NSSAI of the terminal device is changed when the terminal device is in the deregistration state (RM-DEREGISTERED), or for the scenario in which the signed S-NSSAI included in the subscription information of the terminal device, changes when the terminal device moves from the second PLMN to the first PLMN and resides in the second PLMN, the device can be used to ensure that the NSSAI configured of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0305] Optionally, the registration request message is an initial registration request message, or a registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network.

[0306] As shown in FIG. 8F, another communication device may include a receiving unit 851, a processing unit 852, and a sending unit 853. The device may be a terminal device or a chip.

[0307] The device may be configured to perform the UE operations of FIG. 7. For example, the receiving module 851 is configured to receive the updated route selection policy of the user equipment; the processing unit 852 is configured to determine that the transmission of update indication information to the network element of the access and mobility control function is not recorded; the sending module 853 is configured to send update indication information to the access and mobility control function network element, where the update indication information is used to instruct the access and mobility control function network element to send the updated configured network segment selection assistance information to the terminal device, and the access control function network element and mobility located in a visited public land mobile network; and the processing unit 852 is configured to record that update indication information has been sent to the visited PLMN.

[0308] Therefore, for the scenario in which the signed S-NSSAI of the terminal device is changed when the terminal device is in the deregistration state (RM-DEREGISTERED), or for the scenario in which the signed S-NSSAI included in the subscription information of the terminal device, changes when the terminal device moves from the second PLMN to the first PLMN and resides in the second PLMN, the device can be used to ensure that the NSSAI configured of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0309] As shown in FIG. 8G, another communication device may include a receive module 861 and a send module 862. The device may be a network element or an access and mobility control chip.

[0310] The device may be configured to perform the AMF operations of FIG. 10 or FIG. 11. For example, the receiving module 861 is configured to obtain the first configured network segment selection sub-information associated with the first network of the terminal device; and the sending unit 862 is configured to send the first configured network segment selection assistance information and indication information to the terminal device, where the indication information is used to direct the terminal device to delete the second configured network segment selection assistance information associated with a different network than the first network.

[0311] Therefore, the communication device can be used to ensure that the NSSAI configured first PLMN used by the terminal device is updated in time, thereby improving the user experience of the terminal device and saving network resources.

[0312] Optionally, the indication information is further used to instruct the terminal apparatus to remove the allowed network segment selection auxiliary information associated with the other network.

[0313] Optionally, in order to obtain the first configured network segment selection assistance information associated with the first network, the terminal device, the acquisition module 861 is specifically configured to: receive, from the network management element data, updated signed S-NSSAI associated with the first network, the terminal devices; and obtaining the first configured network segment selection assistance information based on the updated subscribed S-NSSAIs. The communication device determines that the first configured network segment selection assistance information is obtained based on the updated signed S-NSSAIs, so that the sending module 862 sends the indication information to the terminal device.

[0314] Optionally, in order to send the first configured network segment selection auxiliary information and indication information, the sending module 862 is specifically configured to: send a user equipment configuration update command to the terminal device, where the user equipment configuration update command includes the first configured network segment selection auxiliary information segment and indication information; or sending a registration acceptance message to the terminal device, where the registration acceptance message includes the first configured network segment selection auxiliary information and indication information.

[0315] As shown in FIG. 8H, another communication device may include a receiving module 871 and a processing module 872. The device may be a terminal device or a chip.

[0316] The device may be configured to perform the operations of the terminal device of FIG. 10 or FIG. 12. For example, the receiving module 871 is configured to receive, from the network element of the access and mobility control function in the first network, the first configured network segment selection assistance information corresponding to the first network of the terminal device; and the processing unit 872 is configured to: delete the second configured network segment selection assistance information associated with a different network than the first network; and replacing the third configured stored network segment selection assistance information associated with the first network with the first configured network segment selection assistance information.

[0317] Therefore, the communication device can be used to ensure that the NSSAI configured of the first PLMN used by the terminal device is updated in a timely manner, thereby improving the user experience of the terminal device and saving network resources.

[0318] Optionally, the receiving module 871 is further configured to receive indication information from the network element of the access and mobility control function, where the indication information is used to direct the terminal device to remove the second configured network segment selection assistance information.

[0319] Optionally, the processing module 872 is further configured to remove the allowed network segment selection assistance information associated with another network. In addition, optionally, the receiving unit 871 is configured to receive indication information from the network element of the access and mobility control function, where the indication information is used to direct the terminal device to delete the second configured network segment selection auxiliary information and the allowed network segment selection auxiliary information.

[0320] FIG. 9 is another possible schematic block diagram of the communication device in the above embodiments. As shown in FIG. 10, the device includes a transceiver 1001 and a processor 1002.

[0321] For example, processor 1002 may be a general purpose microprocessor, a data processing circuit, an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA) circuit. The device may further include a memory 1003. The memory is configured to communicate with the processor 1002 and store the necessary computer program 10031 of the device.

[0322] In addition, the communication method in the above embodiments provides a computer-readable storage medium 1004 (for example, a hard disk). The computer-readable storage medium stores the computer program 10041 of the device. The computer program 10041 may be loaded into the processor 1002.

[0323] When the computer program 10031 or 10041 is running on a computer (eg, processor 1002), the computer may be given the ability to perform the above methods.

[0324] For example, in an embodiment, the processor 1002 is configured to perform the operations or functions of the aforementioned Access and Mobility Function (AMF) network element. The transceiver 1001 is configured to communicate between the device and a UDM, a RAN device, or another AMF.

[0325] In another embodiment, the processor 1002 is configured to perform the operations or functions of the aforementioned Unified Data Management Network Element (UDM). The transceiver 1001 is configured to communicate between the device and the AMF.

[0326] In another embodiment, the processor 1002 is configured to perform operations or functions of the aforementioned terminal device (UE). The transceiver 1001 is configured to implement communication between the device and the AMF, and between the device and the RAN device.

[0327] The processor for performing the functions of the communication device in this application may be a central processing unit (CPU), general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other programmable logic device , a transistor logic device, a hardware component, or any combination thereof. The controller/processor may implement or execute various exemplary logical blocks, modules, and circuits described with reference to the content disclosed in this application. Alternatively, the processor may be a combination of processors that implement a computing function, such as a combination of one or more microprocessors, or a combination of a DSP and a microprocessor.

[0328] The steps of a method or algorithm described in conjunction with the content disclosed in this application may be implemented in hardware or may be implemented by a processor by executing a software instruction. The program instruction may include a corresponding program module. The software module may be located in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, register, hard disk, removable hard disk, CD-ROM, or any other storage medium known in the art. For example, a storage medium is coupled to the processor such that the processor can read information from, or write information to, the storage medium. Of course, the storage medium may be a component of the processor. The processor and storage medium may reside in an ASIC. In addition, the ASIC may be located in the communication device. Of course, the processor and the storage medium may exist as discrete components in the communication device. Memory 1003 may include volatile memory, such as random-access memory (RAM). The memory 1003 may include non-volatile memory (non-volatile memory), such as flash memory (flash memory), hard disk drive (hard disk drive, HDD) or solid-state drive (solid-state drive, SSD). The memory 1003 may further include a combination of the above types of storage devices.

[0329] Therefore, another aspect of this application provides a computer-readable storage medium. The computer-readable storage medium stores the instruction. When an instruction is executed on a computer, the computer is enabled to perform the above methods.

[0330] Another aspect of this application provides a computer program product that includes instructions. When the computer program product is run on the computer, the computer is enabled to perform the above methods.

[0331] Another aspect of this application provides a communication system including an access and mobility control network element configured to perform the method according to claim 1 or 2 of the claims.

[0332] Another aspect of this application provides a communication system, including: a unified data administration network element configured to perform a method according to any one of claims 3-10 of the formula; and a network element of the access and mobility control function, configured to perform the method according to any one of paragraphs. 11-14 formulas.

[0333] Yet another aspect of this application provides a communication system including an access and mobility control network element configured to perform a method according to any one of claims. 15-21 formulas. Optionally, the system further includes a terminal device configured to perform the method of claim 22 or 23.

[0334] Yet another aspect of this application provides a communication system including an access and mobility control network element configured to perform the method of any one of claims. 31-36 formulas. Optionally, the system further includes a terminal device configured to perform the method of any one of claims. 37-41 formulas.

[0335] One skilled in the art may be aware that, in combination with the examples described in the embodiments disclosed herein, the blocks and steps of an algorithm may be implemented using electronic hardware or a combination of computer software and electronic hardware. The performance of functions by hardware or software depends on the specific applications and the states of the design constraints of the technical solutions. A person skilled in the art can use various methods to implement the described functions for each particular application, but such an implementation should not be considered to be outside the scope of this application.

[0336] One skilled in the art can clearly understand that for the purposes of a convenient and concise description of the detailed working process of the aforementioned system, device, and unit, reference may be made to the corresponding process in the aforementioned method embodiments, and the details are not described again here.

[0337] In several embodiments provided herein, it should be understood that the disclosed system, apparatus, and method may be implemented in other ways. For example, the device embodiment described is only an example. For example, the division into blocks is just a division of logical functions, and may be another division in a real implementation. For example, many blocks or components may be combined or integrated into another system, or certain functions may be ignored or not performed. In addition, the displayed or discussed interconnections or direct links or communication connections may be implemented using some interfaces. Indirect connections or communication connections between devices or units may be implemented in electronic, mechanical or other forms.

[0338] Blocks described as separate parts may or may not be physically separate, and parts shown as blocks may or may not be physical blocks, may be located in the same location, or may be distributed over multiple network blocks. Some or all of the blocks may be selected based on actual requirements in order to achieve the objectives of the decisions in the mentioned embodiments.

[0339] In addition, the functional blocks in the embodiments of this application may be integrated into one processing unit, or each of the units may exist physically separately, or two or more units are integrated into one unit.

[0340] When the functions are implemented as a functional block of software and sold or used as a standalone product, the functions may be stored on a computer-readable storage medium. Based on this understanding, the essence of the technical solutions in this application, or the part that contributes to the prior art, or some of the technical solutions can be implemented in the form of a software product. The software product is stored on a storage medium and includes several instructions for instructing a computing device (which may be a personal computer, a server, or a network device) to perform all or some of the steps of the methods described in the embodiments of this application. The above storage media includes: any media that can store program code, such as a USB flash drive, removable hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk.

[0341] The above description is only a specific implementation of this application, but is not intended to limit the scope of protection of this application. Any change or replacement readily detectable by a person skilled in the art within the technical scope disclosed in this application should/should fall within the scope of this application. Therefore, the scope of this application is protected by the claims.

Claims (142)

1. A communication method, the method comprising: receiving, by the network element of the access and mobility control function in the first public land mobile network, a registration request message from the terminal device; and upon determining that the first condition is met, the network element sending the access and mobility control function the configured assistance information of selecting the network segment of the first public land mobile network to the terminal device, the first condition comprising any of the following: The registration request message is an initial registration request message , or a registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network. 2. The method of claim 1, wherein the first condition further comprises: the access and mobility control function network element obtains the terminal device subscription information from the unified data administration network element. 3. A communication method, the method comprising: receiving by means of a unified management network element data from the first network element of the access and mobility control function in the first public land mobile network of a request for obtaining information of the subscription of the terminal device, while the first network element of the access and mobility management function is a network element of the access and mobility control function, which serves the terminal device; sending, by the unified network administration data element, the subscription information of the terminal device to the first network element of the access and mobility control function, the subscription information of the terminal device comprising at least signed auxiliary network segment selection information of the terminal device; and instructing, by means of the unified data management network element, the first network element of the access and mobility control function to update the first configured network segment selection auxiliary information, wherein the first configured network segment selection auxiliary information is the configured network segment selection auxiliary information of the first public land mobile network, with which the terminal device requests registration. 4. The method of claim 3, wherein instructing, by means of the unified data administration network element, the first network element of the access and mobility control function to update the first configured network segment selection assistance information comprises: sending, by means of the unified data administration network element, the first indication information to the first access and mobility management function network element, wherein the first indication information is used to direct the first access and mobility control function network element to update the first configured network segment selection auxiliary information. 5. The method of claim 3, wherein instructing, by means of the unified data administration network element, the first network element of the access and mobility control function to update the first configured network segment selection assistance information comprises: sending, by the unified data administration network element, a terminal device subscription modification notification message to the first network element of the access and mobility control function, wherein the terminal device subscription modification notification message contains signed network segment selection assistance information for the terminal device. 6. The method according to any one of paragraphs. 3-5, wherein the method further comprises: sending, by the Unified Data Management Network Element, a request to subscribe to the first Access and Mobility Management Function Network Element, wherein the subscription request is used to request the first Access and Mobility Management Function Network Element to send a notification message to the Unified Data Management Network Element upon completion updating the first configured network segment selection assistance information; and receiving by the unified data administration network element the notification message from the first network element of the access and mobility control function. 7. The method according to any one of paragraphs. 3-6, wherein the method further comprises: after instructing, by the unified data management network element, the first network element of the access and mobility management function to update the first configured network segment selection auxiliary information, determining by the unified data administration network element that the update of the first configured network segment selection auxiliary information does not need to be initiated. 8. The method of claim 6, wherein the method further comprises: after the unified data manager receives the notification message from the first network element of the access and mobility control function, the determination by the unified data manager that the update of the first configured network segment selection assistance information does not need to be triggered. 9. The method according to any one of paragraphs. 3-8, wherein before instructing, by the unified data administration network element, the first access and mobility management function network element to update the first configured network segment selection assistance information, the method further comprises: determining by the unified data management network element that it is necessary to update the configured network segment selection assistance information of one or more public land mobile networks of the terminal device, wherein one or more public land mobile networks contains the first public land mobile network. 10. The method of claim 9, wherein determining, by means of the unified network administration data element, that it is necessary to update the configured network segment selection assistance information of one or more public land mobile networks of the terminal device comprises: when determining that the subscription information of the terminal device is changed, determining by the unified data management network element that the configured network segment selection assistance information of one or more public land mobile networks of the terminal device needs to be updated. 11. Communication method, and the method contains: the first network element of the access and mobility control function in the first public land mobile network sends to the unified network element of administration data a request to obtain subscription information of the terminal device, while the first network element of the access and mobility control function is the network element of the access and mobility control function that serves terminal device; receiving, by the first network element of the access and mobility management function, subscription information of the terminal device from the unified data administration network element, wherein the subscription information of the terminal device comprises at least signed auxiliary network segment selection information of the terminal device; and initiating, by the first network element of the access and mobility control function, updating the first configured network segment selection assistance information according to the indication of the unified data administration network element, wherein the first configured network segment selection assistance information is the configured network segment selection assistance information with which the terminal device requests registration. 12. The method of claim 11, wherein the first network element triggering the access and mobility management function to update the first configured network segment selection assistance information in accordance with the indication of the unified data administration network element comprises: upon receiving the first indication information from the unified data management network element, causing the first network element of the access and mobility control function to update the first configured network segment selection assistance information based on the signed network segment selection assistance information. 13. The method of claim 11, wherein the first network element triggering the access and mobility management function to update the first configured network segment selection assistance information in accordance with the indication of the unified data administration network element comprises: upon receiving the terminal device subscription modification notification message from the unified data administration network element, initiating by the first network element of the access and mobility control function to update the first configured network segment selection auxiliary information based on the signed network segment selection auxiliary information of the terminal device contained in the terminal device subscription modification notification message devices. 14. The method according to any one of paragraphs. 11-13, wherein the method comprises: receiving by the first network element of the access and mobility management function a subscription request from the unified data management network element, wherein the subscription request is used to request the first network element of the access and mobility management function to send a notification message to the unified data administration network element after the update of the first configured assistance information is completed network segment selection; and after receiving the configuration update complete message from the terminal device, the first network element of the access and mobility management function sends a notification message to the unified data management network element, wherein the configuration update complete message is used to indicate that the terminal device has completed updating the first configured network segment selection assistance information . 15. Communication method, and the method contains: obtaining, by the network element of the access and mobility control function, the signed auxiliary network segment selection information of the terminal device; receiving by the network element of the access and mobility control function the first configured network segment selection assistance information of the terminal device, wherein the first configured network segment selection assistance information is the configured network segment selection assistance information of the first public land mobile network with which the terminal device requests registration; determining, by the network element of the access and mobility control function, based on the signed network segment selection assistance information, whether to update the first configured network segment selection assistance information; and if the network element of the access and mobility control function determines that it is necessary to update the first configured network segment selection assistance information, determining the second configured network segment selection assistance information based on the signed network segment selection assistance information, and sending the second configured network segment selection assistance information to the terminal device . 16. The method of claim 15, wherein obtaining, by the network element, the access and mobility control function of the first configured network segment selection assistance information of the terminal device comprises: receiving, by the network element of the access and mobility control function, a registration request message from the terminal device, wherein the registration request message contains the first configured network segment selection assistance information. 17. The method of claim 16, wherein the registration request message is an initial registration request message, or the registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network. 18. The method of claim 15, wherein obtaining, by the network element of the access and mobility control function, the first configured auxiliary network segment selection information of the terminal device comprises: obtaining, by the network element of the access and mobility control function, a terminal device context, wherein the terminal device context contains the first configured network segment selection assistance information. 19. The method according to any one of paragraphs. 15-18, wherein determining by the network element of the access and mobility control function, based on the signed network segment selection assistance information, whether to update the first configured network segment selection assistance information comprises: determining by the network element of the access and mobility control function whether the first configured network segment selection auxiliary information is the same as the signed network segment selection auxiliary information, and if the first configured network segment selection auxiliary information is different from the signed network segment selection auxiliary information, determining, that the first configured network segment selection auxiliary information needs to be updated to the second configured network segment selection auxiliary information, wherein the one network segment selection auxiliary information contained in the second configured network segment selection auxiliary information is the same as the signed network segment selection auxiliary information. 20. The method according to any one of paragraphs. 15-18, wherein the first configured network segment selection assistance information is the configured network segment selection assistance information of the visited public terrestrial public network of the terminal device, and the network element determines the access and mobility control function based on the signed network segment selection assistance information whether to update the first configured network segment selection information, contains: determining, by the network element, an access and mobility control function based on the first configured network segment selection assistance information, the signed network segment selection assistance information, and a mapping relationship between the first configured network segment selection assistance information and the configured network segment selection assistance information of the public terrestrial home network terminal device whether to update the first configured sub-information of network segment selection. 21. The method according to any one of paragraphs. 15-20, wherein the method further comprises: storing, by the network element of the access and mobility control function, the second configured network segment selection assistance information in the context of the terminal device. 22. Communication method, and the method contains: sending, by the terminal device, a registration request message to the network element of the access and mobility control function, wherein the registration request message contains the first configured network segment selection auxiliary information of the terminal device, and the first configured network segment selection auxiliary information is the configured network segment selection auxiliary information of the first land mobile network public domain with which the terminal device requests registration; and receiving by the terminal device the second configured network segment selection assistance information for the first public land mobile network. 23. The method of claim 22, wherein the registration request message is an initial registration request message or the registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network. 24. Communication device, wherein the communication device is located in the first public land mobile network and contains: a receiving module, configured to receive a registration request message from the terminal device; and a processing module configured to: upon determining that the first condition is met, send the configured network segment selection assistance information of the first public land mobile network to the terminal device using the sending module, the first condition including any of the following: the registration request message is a message an initial registration request or a registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network. 25. The communications device of claim 24, wherein the first condition further comprises: the access and mobility control function network element obtains the terminal device subscription information from the unified data management network element. 26. A communication device, comprising: a receiving module configured to receive from the first network element of the access and mobility control function in the first public land mobile network, a request to obtain subscription information of the terminal device, wherein the first network element of the access and mobility control function is a network element of the access and mobility control function, which serves the terminal device; and a sending module configured to send subscription information of the terminal device to the first network element of the access and mobility control function, wherein the subscription information of the terminal device contains at least signed auxiliary network segment selection information of the terminal device; and further configured to cause the first network element of the access and mobility control function to update the first configured network segment selection assistance information, wherein the first configured network segment selection assistance information is the configured network segment selection assistance information with which the terminal device requests registration. 27. Communication device, wherein the communication device is located in the first public land mobile network and contains: a sending module configured to send a request data to the unified management network element to obtain subscription information of the terminal device, wherein the communication device is an access and mobility control network element that serves the terminal device; a receiving module configured to receive subscription information of the terminal device from the unified data administration network element, wherein the subscription information of the terminal device comprises at least signed auxiliary network segment selection information of the terminal device; and a processing unit configured to update the first configured network segment selection assistance information according to the indication of the unified data management network element, wherein the first configured network segment selection assistance information is the configured network segment selection assistance information with which the terminal device requests registration. 28. A communication device, comprising: an acquisition module configured to obtain the signed auxiliary network segment selection information of the terminal device; and obtaining the first configured network segment selection assistance information of the terminal device, wherein the first configured network segment selection assistance information is the configured network segment selection assistance information of the first public land mobile network in which the terminal device requests registration; and a processing unit configured to: determine, based on the signed subnet selection assistance information, whether to update the first configured subnetwork selection subinformation; and if it is necessary to update the first configured network segment selection assistance information, determining the second configured network segment selection assistance information based on the signed network segment selection assistance information, and sending the second configured network segment selection assistance information to the terminal device with the sending unit. 29. A communication device, comprising: a sending module configured to send a registration request message to the network element of the access and mobility management function, wherein the registration request message contains the first configured network segment selection auxiliary information of the terminal device, and the first configured network segment selection auxiliary information is the configured network segment selection auxiliary information of the first the public land mobile network with which the terminal device requests registration; and a receiving module configured to receive the second configured network segment selection assistance information for the first public land mobile network. 30. The communication apparatus of claim 29, wherein the registration request message is an initial registration request message or the registration request message is sent after the terminal device transitions from the second public land mobile network to the first public land mobile network. 31. Communication method, comprising: receiving, by the network element of the access and mobility control function in the first network, the updated signed auxiliary information of the network segment selection of the terminal device from the data management network element; obtaining, based on the updated signed network segment selection assistance information, the first configured network segment selection assistance information associated with the first network of the terminal device; and sending, by the network element of the access and mobility control function, the first configured network segment selection auxiliary information and indication information to the terminal device, wherein the indication information is used to instruct the terminal device to delete the second configured network segment selection auxiliary information associated with a different network than the first network. 32. The method of claim 31, wherein obtaining, based on the updated signed network segment selection assistance information, the first configured network segment selection assistance information associated with the first network, the terminal device comprises: determining, by the network element of the access and mobility control function, the first configured network segment selection assistance information based on the updated signed network segment selection assistance information; or after receiving the updated signed network segment selection assistance information, obtaining, by the network element of the access and mobility control function, the first configured network segment selection assistance information from the network element of the network segment selection function. 33. The method of claim 31 or 32, wherein the indication information is further used to instruct the terminal device to remove the allowed network segment selection assistance information associated with the other network. 34. The method according to any one of paragraphs. 31-33, in which sending, by means of the network element of the access and mobility control function, indication information to the terminal device comprises: if the access and mobility control network element determines that the first configured network segment selection auxiliary information is obtained based on the updated signed network segment selection auxiliary information, sending the access and mobility control network element indication information to the terminal device. 35. The method according to any one of paragraphs. 31-34, wherein sending, by the network element of the access and mobility control function, the first configured network segment selection auxiliary information and indication information to the terminal device comprises: sending, by the network element of the access and mobility control function, a user equipment configuration update command to the terminal device, wherein the user equipment configuration update command contains the first configured network segment selection auxiliary information and indication information. 36. The method according to any one of paragraphs. 31-34, wherein sending, by the network element of the access and mobility control function, the first configured network segment selection auxiliary information and indication information to the terminal device comprises: sending, via the access and mobility management function network element, a registration acceptance message to the terminal device, wherein the registration acceptance message contains the first configured network segment selection auxiliary information and indication information. 37. Communication method, comprising: receiving by the terminal device from the network element of the access and mobility control function in the first network of the first configured auxiliary information for selecting a network segment of the terminal device of the first network; deleting, by the terminal device, the second configured network segment selection assistance information associated with a different network than the first network; replacing, by the terminal device, the stored third configured network segment selection assistance information associated with the first network with the first configured network segment selection assistance information. 38. The method of claim 37, further comprising: reception by the terminal device of indication information from the network element of the access and mobility control function, while deletion by the terminal device of the second configured network segment selection assistance information associated with a different network than the first network comprises: deleting, by the terminal device in accordance with the indication information, the second configured network segment selection auxiliary information associated with a different network than the first network. 39. The method of claim 38, wherein the indication information is used to direct the terminal device to delete the second configured network segment selection auxiliary information. 40. The method according to any one of paragraphs. 37-39, additionally containing: deleting, by the terminal device, the allowed network segment selection assistance information associated with the other network. 41. The method of claim 40, further comprising: receiving, by the terminal device, indication information from the network element of the access and mobility control function, wherein the indication information is used to instruct the terminal device to remove the second configured network segment selection auxiliary information and the allowed network segment selection auxiliary information. 42. Communication device configured to perform the method according to any one of paragraphs. 31-36. 43. Communication device configured to perform the method according to any one of paragraphs. 37-41. 44. Communication device, containing: a receiving module, configured to: receive the updated signed assistance information of the network segment selection of the terminal device from the data management network element; and obtaining, based on the updated signed subnet selection assistance information, the first configured subnetwork selection subinformation associated with the first network of the terminal device; and a sending module configured to send the first configured network segment selection assistance information and indication information to the terminal device, wherein the indication information is used to direct the terminal device to delete the second configured network segment selection assistance information associated with a different network than the first network. 45. The communication device according to claim 44, in which the obtaining module is configured to determine the first configured network segment selection assistance information based on the updated signed network segment selection assistance information; or the obtaining module is configured to: after receiving the updated signed network segment selection assistance information, obtain the first configured network segment selection assistance information from the network element of the network segment selection function. 46. The communication device according to claim 44 or 45, wherein if the communication device determines that the first configured network segment selection assistance information has been received based on the updated signed network segment selection assistance information, the sending module sends the indication information to the terminal device. 47. Communication device according to any one of paragraphs. 44 to 46, wherein the sending module is configured to send a user equipment configuration update command to the terminal device, wherein the user equipment configuration update command contains the first configured network segment selection auxiliary information and indication information. 48. Communication device according to any one of paragraphs. 44-46, in which the sender is configured to send a registration acceptance message to the terminal device, the registration acceptance message including the first configured network segment selection auxiliary information and indication information. 49. Communication device according to any one of paragraphs. 44-48, wherein the communication device is an access and mobility control network element located in the first network. 50. A communication device, comprising: a receiving module configured to receive, from the network element of the access and mobility management function in the first network, the first configured network segment selection assistance information of the first network terminal apparatus; and a processing unit configured to delete a second configured network segment selection auxiliary information associated with a different network than the first network; and replacing the stored third configured network segment selection assistance information associated with the first network with the first configured network segment selection assistance information. 51. The communication device according to claim 50, wherein the receiving module is further configured to receive indication information from the network element of the access and mobility control function; and the processing unit is configured to delete, according to the indication information, the second configured network segment selection auxiliary information associated with a different network than the first network. 52. The communication apparatus of claim 51, wherein the indication information is used to direct the terminal device to remove the second configured network segment selection auxiliary information. 53. Communication device according to any one of paragraphs. 50-52, wherein the communication device comprises a terminal device. 54. Communication device, containing: a transceiver configured to receive the updated signed auxiliary network segment selection information of the terminal device from the data management network element; and a processor configured to obtain, based on the updated signed network segment selection assistance information, the first configured network segment selection assistance information associated with the first network, the terminal device, wherein the transceiver is further configured to send the first configured network segment selection assistance information and indication information to the terminal device, wherein the indication information is used to direct the terminal device to delete the second configured network segment selection assistance information associated with a different network than the first network. 55. The communication device according to claim 54, in which the processor is configured to determine the first configured network segment selection assistance information based on the updated signed network segment selection assistance information; or the processor is configured to: after the transceiver receives the updated signed network segment selection assistance information, obtain the first configured network segment selection assistance information from the network segment selection function network element by the transceiver. 56. The communication device according to claim 54 or 55, wherein the processor is configured such that: if the first configured network segment selection auxiliary information is obtained based on the updated signed network segment selection auxiliary information, control the transceiver to send indication information to the terminal device. 57. Communication device according to any one of paragraphs. 54-56, wherein the transceiver is configured to send a user equipment configuration update command to the terminal device, wherein the user equipment configuration update command contains the first configured network segment selection auxiliary information and indication information. 58. Communication device according to any one of paragraphs. 54-56, wherein the transceiver is configured to send a registration acceptance message to the terminal device, the registration acceptance message including the first configured network segment selection sub-information and indication information. 59. Communication device according to any one of paragraphs. 54-58, wherein the communication device is an access and mobility control network element located in the first network. 60. A communication device, comprising: a receiver configured to receive, from the network element of the access and mobility control function in the first network, the first configured network segment selection assistance information of the first network terminal device; and a processor configured to: delete a second configured network segment selection assistance information associated with a different network than the first network; and replacing the stored third configured network segment selection assistance information associated with the first network with the first configured network segment selection assistance information. 61. The communications device of claim 60, wherein the receiver is further configured to receive indication information from the network element of the access and mobility control function; and the processor is configured to delete, according to the indication information, the second configured network segment selection auxiliary information associated with a different network than the first network. 62. The communication apparatus of claim 61, wherein the indication information is used to direct the terminal device to remove the second configured network segment selection auxiliary information. 63. Communication device according to any one of paragraphs. 60-62, in which the communication device is a terminal device. 64. A computer-readable storage medium containing an instruction, and when the instruction is executed on a computer, the computer is allowed to perform the method according to any one of paragraphs. 1-23 or 31-41. 65. A communication system, comprising: a data management network element, configured to send the updated signed auxiliary network segment selection information of the terminal device; and an access and mobility control function network element in the first network, configured to: receive updated signed network segment selection assistance information from the data management network element; based on the updated signed network segment selection assistance information, obtaining a first configured network segment selection assistance information associated with the first network of the terminal device; and sending the first configured network segment selection assistance information and indication information to the terminal device, wherein the indication information is used to direct the terminal device to remove the second configured network segment selection assistance information associated with a different network than the first network.

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