Method for selecting non-trusted non-3GPP network, user terminal and communication system

Abstract

The present disclosure provides a method for selecting an untrusted non-3GPP network, a user terminal and a communication system. The method for selecting an untrusted non-3GPP network includes: when the HPLMN selects to access the untrusted non-3GPP network, selecting a first non-3GPP interworking function N3IWF entity of the untrusted non-3GPP network supporting the HPLMN slice from ANDSP according to the HPLMN slice; and sending a registration request to the first N3IWF entity.

Description

[0001] This application is a divisional application of the Chinese patent application submitted to the China Patent Office on March 15, 2022, with application number 202210253745.3 and invention name "Method for selecting a non-trusted non-3GPP network, user terminal and communication system". Technical Field

[0002] The present disclosure relates to the field of communications, and in particular to a method for selecting a non-trusted non-3GPP (3rd Generation Partnership Project) network, a user terminal and a communication system. Background Art

[0003] Currently, 3GPP's 5G UE (User Equipment) accesses an untrusted non-3GPP network and can only connect to the N3IWF (Non-3GPP InterWorking Function) entity pre-configured on the network side. The network side can set the corresponding N3IWF based on the slices subscribed by the UE. Summary of the invention

[0004] The inventors noted that in the related art, when a N3IWF cannot support all slices of the UE, it is impossible to select the corresponding N3IWF based on the slice of the UE's current service. Different N3IWFs support different slices, which can give the network flexibility in service configuration and network resource deployment.

[0005] Accordingly, the present disclosure provides a solution for selecting a non-trusted non-3GPP network, which enables the UE to select the corresponding N3IWF according to the slice required for the current service, thereby improving the flexibility of network resource deployment.

[0006] According to a first aspect of an embodiment of the present disclosure, a method for selecting an untrusted non-3GPP network is provided, which is executed by a user terminal, including: when selecting to access an untrusted non-3GPP network, selecting a non-3GPP interworking function N3IWF entity of an untrusted non-3GPP network that supports the slice from a pre-configured access network discovery and selection policy ANDSP according to the slice required by the current service; and sending a registration request to a core network device through the N3IWF entity, so as to access the slice after successful registration.

[0007] In some embodiments, in the case of selecting to access an untrusted non-3GPP network, selecting a N3IWF entity that supports the slice from ANDSP according to the slice required for the current service includes: in the case of determining that access to an untrusted non-3GPP network is selected in the home public land mobile network HPLMN, selecting a first N3IWF entity of the untrusted non-3GPP network that supports the HPLMN slice from the ANDSP according to the HPLMN slice required for the current service.

[0008] In some embodiments, sending a registration request to a core network device through the N3IWF entity includes: sending a registration request to a core network device through the first N3IWF entity so as to access the HPLMN slice after successful registration.

[0009] In some embodiments, in the case of selecting to access an untrusted non-3GPP network, selecting a N3IWF entity that supports the slice from ANDSP according to the slice required for the current service includes: in the case of determining that an untrusted non-3GPP network is selected for access when accessing a public land mobile network VPLMN, querying a VPLMN slice that has a mapping relationship with the HPLMN slice required for the current service; and selecting a second N3IWF entity of the untrusted non-3GPP network that supports the VPLMN slice from ANDSP.

[0010] In some embodiments, sending a registration request to a core network device through the N3IWF entity includes: sending a registration request to a core network device through the second N3IWF entity so as to access the VPLMN slice after successful registration.

[0011] In some embodiments, during access to the HPLMN core network, a first ANDSP message sent by the HPLMN device is received, wherein the first ANDSP message includes a first N3IWF entity identifier of an untrusted non-3GPP network within the HPLMN and HPLMN slice information supported by the first N3IWF entity.

[0012] In some embodiments, during the process of accessing the HPLMN core network, a second ANDSP information sent by the HPLMN device is received, wherein the second ANDSP information includes a second N3IWF entity identifier of a non-trusted non-3GPP network within each VPLMN of a plurality of VPLMNs and VPLMN slice information supported by the second N3IWF entity, and according to the roaming agreement between each VPLMN and the HPLMN, the VPLMN slice can be mapped to the HPLMN slice subscribed to by the user terminal.

[0013] In some embodiments, the HPLMN device is a policy control function PCF entity in the HPLMN; and the core network device is an access and mobility management function AMF entity.

[0014] According to a second aspect of an embodiment of the present disclosure, a user terminal is provided, comprising: a first processing module, configured to, when selecting to access an untrusted non-3GPP network, select a non-3GPP interworking function N3IWF entity of an untrusted non-3GPP network that supports the slice from a pre-configured access network discovery and selection policy ANDSP according to the slice required by the current service; and a second processing module, configured to send a registration request to a core network device through the N3IWF entity, so as to access the slice after successful registration.

[0015] In some embodiments, the first processing module is configured to, when determining that the home public land mobile network HPLMN chooses to access an untrusted non-3GPP network, select a first N3IWF entity of the untrusted non-3GPP network that supports the HPLMN slice from the ANDSP according to the HPLMN slice required for the current service.

[0016] In some embodiments, the second processing module is configured to send a registration request to the core network device through the first N3IWF entity so as to access the HPLMN slice after successful registration.

[0017] In some embodiments, the first processing module is configured to, when it is determined that when accessing a public land mobile network VPLMN, selects a second N3IWF entity of the non-trusted non-3GPP network that supports the VPLMN slice, query a VPLMN slice that has a mapping relationship with the HPLMN slice required for the current service, and select from the ANDSP a second N3IWF entity of the non-trusted non-3GPP network that supports the VPLMN slice.

[0018] In some embodiments, the second processing module is configured to send a registration request to the core network device through the second N3IWF entity so as to access the VPLMN slice after successful registration.

[0019] In some embodiments, the first processing module is configured to receive a first ANDSP message sent by the HPLMN device during access to the HPLMN core network, wherein the first ANDSP message includes a first N3IWF entity identifier of a non-trusted non-3GPP network within the HPLMN and HPLMN slice information supported by the first N3IWF entity.

[0020] In some embodiments, the first processing module is configured to receive a second ANDSP information sent by the HPLMN device during access to the HPLMN core network, wherein the second ANDSP information includes a second N3IWF entity identifier of a non-trusted non-3GPP network within each VPLMN of multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity, and according to the roaming agreement between each VPLMN and the HPLMN, the VPLMN slice can be mapped to the HPLMN slice subscribed to by the user terminal.

[0021] In some embodiments, the HPLMN device is a PCF entity in the HPLMN; the core network device is an AMF entity.

[0022] According to a third aspect of an embodiment of the present disclosure, a user terminal is provided, comprising: a memory configured to store instructions; a processor coupled to the memory, the processor being configured to execute a method as described in any of the above embodiments based on the instructions stored in the memory.

[0023] According to the fourth aspect of an embodiment of the present disclosure, a communication system is provided, comprising: a user terminal as described in any of the above embodiments; an N3IWF entity, configured to send a registration request to a core network device after receiving the registration request sent by the user terminal; and a core network device, configured to perform registration processing according to the registration request, so that the user terminal can access the slice required for the current service after successful registration.

[0024] In some embodiments, the system also includes: a HPLMN device, configured to select, from among the HPLMN slices subscribed by the user terminal, an HPLMN slice supported by a first N3IWF entity of a non-trusted non-3GPP network in the HPLMN, during the process of the user terminal accessing the HPLMN core network, and send a first ANDSP message to the user terminal, wherein the first ANDSP message includes the first N3IWF entity identifier and the HPLMN slice information supported by the first N3IWF entity.

[0025] In some embodiments, the HPLMN device is also configured to send a second ANDSP message to the user terminal during the process of the user terminal accessing the HPLMN core network, wherein the second ANDSP message includes a second N3IWF entity identifier of a non-trusted non-3GPP network within each VPLMN of multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity, and according to the roaming agreement between each VPLMN and the HPLMN, the VPLMN slice can be mapped to the HPLMN slice subscribed by the user terminal.

[0026] In some embodiments, the HPLMN device is also configured to obtain a second N3IWF entity identifier of a non-trusted non-3GPP network within each VPLMN of the multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity based on a roaming agreement between itself and the multiple VPLMNs.

[0027] In some embodiments, the HPLMN device is a PCF entity in the HPLMN; the core network device is an AMF entity.

[0028] According to a fifth aspect of an embodiment of the present disclosure, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and when the instructions are executed by a processor, the method described in any of the above embodiments is implemented.

[0029] Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 A flowchart of a method for selecting a non-trusted non-3GPP network according to an embodiment of the present disclosure;

[0032] Figure 2 A schematic diagram of the structure of a user terminal according to an embodiment of the present disclosure;

[0033] Figure 3 A schematic diagram of the structure of a user terminal according to another embodiment of the present disclosure;

[0034] Figure 4 A schematic diagram of the structure of a communication system according to an embodiment of the present disclosure;

[0035] Figure 5 A schematic diagram of the structure of a communication system according to another embodiment of the present disclosure;

[0036] Figure 6 The present invention is a flowchart of a method for selecting an untrusted non-3GPP network according to another embodiment of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0038] Unless specifically stated otherwise, the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure.

[0039] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0040] Technologies, methods, and apparatus known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, such technologies, methods, and apparatus should be considered part of the authorization specification.

[0041] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0042] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0043] Figure 1 The flowchart of the method for selecting an untrusted non-3GPP network according to an embodiment of the present disclosure is as follows. In some embodiments, the following method for selecting an untrusted non-3GPP network is executed by a user terminal.

[0044] In step 101, when choosing to access an untrusted non-3GPP network, a N3IWF entity of an untrusted non-3GPP network that supports slices is selected from a pre-configured ANDSP (Access Network Discovery and Selection Policy) according to the slices required for the current service.

[0045] In step 102, a registration request is sent to the core network device through the N3IWF entity so as to access the slice after successful registration.

[0046] In some embodiments, the core network device is an AMF (Access and Mobility Management Function) entity.

[0047] In the method for selecting a non-trusted non-3GPP network provided in the above embodiment of the present disclosure, the user terminal selects the corresponding N3IWF according to the slice required for the current service, thereby improving the flexibility of network resource deployment.

[0048] For example, when it is determined that the HPLMN (Home Public Land Mobile Network) is selected to access an untrusted non-3GPP network, the first N3IWF entity of the untrusted non-3GPP network that supports the HPLMN slice is selected from the ANDSP according to the HPLMN slice (HPLMN S-NSSAIs) required for the current service.

[0049] Next, a registration request is sent to the core network device through the first N3IWF entity so as to access the HPLMN slice after successful registration.

[0050] For another example, when it is determined that a non-trusted non-3GPP network is selected for access in a VPLMN (Visited Public Land Mobile Network), a VPLMN slice (VPLMN S-NSSAIs) having a mapping relationship with a HPLMN slice (HPLMN S-NSSAIs) required for the current service is queried, and a second N3IWF entity of a non-trusted non-3GPP network supporting the VPLMN slice is selected from the ANDSP.

[0051] Next, a registration request is sent to the core network device through the second N3IWF entity so as to access the VPLMN slice after successful registration.

[0052] It should be noted here that the user terminal can access the HPLMN core network through a 3GPP access method or a non-3GPP access method at any time.

[0053] In some embodiments, during access to the HPLMN core network, the user terminal receives a first ANDSP message sent by the HPLMN device, wherein the first ANDSP message includes a first N3IWF entity identifier of an untrusted non-3GPP network within the HPLMN and HPLMN slice information supported by the first N3IWF entity.

[0054] In some embodiments, during the process of accessing the HPLMN core network, the user terminal receives a second ANDSP information sent by the HPLMN device, wherein the second ANDSP information includes a second N3IWF entity identifier of a non-trusted non-3GPP network within each VPLMN of multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity, and according to the roaming agreement between each VPLMN and the HPLMN, the VPLMN slice can be mapped to the HPLMN slice subscribed by the user terminal.

[0055] It should be noted here that, during the process of the user terminal accessing the HPLMN core network, the HPLMN device may send the first ANDSP information and the second ANDSP information to the user terminal separately, or may send the first ANDSP information and the second ANDSP information together to the user terminal.

[0056] In some embodiments, the HPLMN device is a PCF (Policy Control Function) entity in the HPLMN.

[0057] In some embodiments, an extension may be performed after the FQDN of the N3IWF in the N3AN (Non-3GPP Access Node) selection information of the ANDSP to increase the supported slice (S-NSSAIs) information.

[0058] Figure 2 FIG. 1 is a schematic diagram of the structure of a user terminal according to an embodiment of the present disclosure. Figure 2 As shown, the user terminal includes a first processing module 21 and a second processing module 22 .

[0059] The first processing module 21 is configured to select a N3IWF entity of a non-trusted non-3GPP network that supports slices from a pre-configured ANDSP according to the slices required for the current service when choosing to access a non-trusted non-3GPP network.

[0060] The second processing module 21 is configured to send a registration request to the core network device through the N3IWF entity so as to access the slice after successful registration.

[0061] In some embodiments, the core network device is an AMF entity.

[0062] In some embodiments, when the user terminal determines that the HPLMN selects to access the untrusted non-3GPP network, the first processing module 21 is configured to select the first N3IWF entity of the untrusted non-3GPP network supporting the HPLMN slice from ANDSP according to the HPLMN slice required by the current service. The second processing module 22 is configured to send a registration request to the core network device through the first N3IWF entity so as to access the HPLMN slice after the registration is successful.

[0063] In other embodiments, when the user terminal determines that it chooses to access an untrusted non-3GPP network when accessing a public land mobile network VPLMN, the first processing module 21 is configured to query a VPLMN slice that has a mapping relationship with the HPLMN slice required by the current service, and select a second N3IWF entity of an untrusted non-3GPP network that supports the VPLMN slice from the ANDSP. The second processing module 22 is configured to send a registration request to the core network device through the second N3IWF entity so as to access the VPLMN slice after the registration is successful.

[0064] In some embodiments, during the process of the user terminal accessing the HPLMN core network, the first processing module 21 is configured to receive a first ANDSP information sent by the HPLMN device, wherein the first ANDSP information includes a first N3IWF entity identifier of a non-trusted non-3GPP network within the HPLMN and HPLMN slice information supported by the first N3IWF entity.

[0065] In other embodiments, during the process of the user terminal accessing the HPLMN core network, the first processing module 21 is configured to receive a second ANDSP information sent by the HPLMN device, wherein the second ANDSP information includes a second N3IWF entity identifier of a non-trusted non-3GPP network within each VPLMN of multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity, and according to the roaming agreement between each VPLMN and the HPLMN, the VPLMN slice can be mapped to the HPLMN slice subscribed by the user terminal.

[0066] For example, the HPLMN device is a PCF entity in the HPLMN.

[0067] Figure 3 FIG. 1 is a schematic diagram of the structure of a user terminal according to another embodiment of the present disclosure. Figure 3 As shown, the user terminal includes a memory 31 and a processor 32 .

[0068] The memory 31 is used to store instructions. The processor 32 is coupled to the memory 31. The processor 32 is configured to execute the instructions stored in the memory to implement the following steps: Figure 1The method of any one of the embodiments.

[0069] like Figure 3 As shown, the user terminal also includes a communication interface 33 for information exchange with other devices. At the same time, the user terminal also includes a bus 34, through which the processor 32, the communication interface 33, and the memory 31 communicate with each other.

[0070] The memory 31 may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk memory. The memory 31 may also be a memory array. The memory 31 may also be divided into blocks, and the blocks may be combined into virtual volumes according to certain rules.

[0071] In addition, the processor 32 may be a central processing unit (CPU), or may be an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present disclosure.

[0072] The present disclosure also relates to a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, which are executed by a processor to implement the following Figure 1 The method of any one of the embodiments.

[0073] Figure 4 FIG. 1 is a schematic diagram of the structure of a communication system according to an embodiment of the present disclosure. Figure 4 As shown, the communication system includes a user terminal 41, an N3IWF entity 42 and a core network device 43. The user terminal 41 is Figure 2 or Figure 3 A user terminal according to any one of the embodiments.

[0074] The N3IWF entity 42 is configured to send a registration request to the core network device 43 after receiving the registration request sent by the user terminal 41 .

[0075] The core network device 43 is configured to perform registration processing according to the registration request so that the user terminal can access the slice required for the current service after successful registration.

[0076] In some embodiments, the core network device is an AMF entity.

[0077] Figure 5 A schematic diagram of the structure of a communication system according to another embodiment of the present disclosure. Figure 5 and Figure 4 The difference is that in Figure 5 In the illustrated embodiment, the communication system further includes a HPLMN device 44 .

[0078] The HPLMN device 44 is configured to select, from the HPLMN slices to which the user terminal 41 has subscribed, an HPLMN slice supported by the first N3IWF entity of the non-trusted non-3GPP network in the HPLMN during the process of the user terminal 41 accessing the HPLMN core network, and send a first ANDSP message to the user terminal 41, wherein the first ANDSP message includes a first N3IWF entity identifier and HPLMN slice information supported by the first N3IWF entity.

[0079] In some embodiments, the HPLMN device 44 is also configured to send a second ANDSP message to the user terminal 41 during the process of the user terminal 41 accessing the HPLMN core network, wherein the second ANDSP message includes a second N3IWF entity identifier of a non-trusted non-3GPP network within each VPLMN of multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity, and according to the roaming agreement between each VPLMN and the HPLMN, the VPLMN slice can be mapped to the HPLMN slice subscribed by the user terminal.

[0080] For example, the HPLMN device 44 is also configured to obtain the second N3IWF entity identifier of the non-trusted non-3GPP network within each of the multiple VPLMNs and the VPLMN slice information supported by the second N3IWF entity based on the roaming agreement between itself and the multiple VPLMNs.

[0081] In some embodiments, the HPLMN device is a PCF entity in the HPLMN.

[0082] Figure 6 The present invention is a flowchart of a method for selecting an untrusted non-3GPP network according to another embodiment of the present invention.

[0083] In step 601, the HPLMN device configures a first N3IWF entity of an untrusted non-3GPP network within the HPLMN and the HPLMN slice information it supports, and a second N3IWF entity of an untrusted non-3GPP network within the VPLMN and the VPLMN slice information it supports.

[0084] For example, the HPLMN device obtains the second N3IWF entity identifier of the non-trusted non-3GPP network in each of the multiple VPLMNs and the VPLMN slice information supported by the second N3IWF entity based on the roaming agreement between itself and the multiple VPLMNs.

[0085] For example, the HPLMN device is a PCF entity in the HPLMN.

[0086] In step 602, during the process of the user terminal accessing the HPLMN core network, the HPLMN device selects the HPLMN slice supported by the first N3IWF entity of the non-trusted non-3GPP network in the HPLMN from the HPLMN slices subscribed by the user terminal, and sends the first ANDSP information to the user terminal through the AMF, wherein the first ANDSP information includes the first N3IWF entity identifier and the HPLMN slice information supported by the first N3IWF entity.

[0087] In step 603, the HPLMN device also sends a second ANDSP message to the user terminal through the AMF, wherein the second ANDSP message includes a second N3IWF entity identifier of a non-trusted non-3GPP network in each VPLMN of the multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity. According to the roaming agreement between each VPLMN and the HPLMN, the VPLMN slice can be mapped to the HPLMN slice subscribed by the user terminal.

[0088] It should be noted that the HPLMN device may also send the first ANDSP information and the second ANDSP information together to the user terminal.

[0089] In step 604a, if the user terminal determines to select access to an untrusted non-3GPP network in the HPLMN, the user terminal selects the first N3IWF entity of the untrusted non-3GPP network that supports the HPLMN slice from the ANDSP according to the HPLMN slice required for the current service.

[0090] In step 605a, the user terminal sends a registration request to the core network device through the first N3IWF entity so as to access the HPLMN slice after successful registration.

[0091] In step 604a, if the user terminal determines to select access to an untrusted non-3GPP network in the VPLMN, the user terminal queries a VPLMN slice that has a mapping relationship with the HPLMN slice required for the current service, and selects a second N3IWF entity of the untrusted non-3GPP network that supports the VPLMN slice from the ANDSP.

[0092] In step 605b, the user terminal sends a registration request to the core network device through the second N3IWF entity so as to access the VPLMN slice after successful registration.

[0093] By implementing the above-mentioned embodiments of the present disclosure, the user terminal can accurately select the N3IWF associated with the currently required slice according to the N3IWF in ANDSP and the slices supported by the N3IWF, thereby accessing the correct non-trusted non-3GPP network.

[0094] In some embodiments, the functional unit described above can be implemented as a general-purpose processor, a programmable logic controller (PLC), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component or any appropriate combination thereof for performing the functions described in the present disclosure.

[0095] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0096] The description of the present disclosure is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present disclosure to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present disclosure, and to enable those of ordinary skill in the art to understand the present disclosure and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A method for selecting an untrusted non-3GPP network, performed by a user terminal, comprising: In the case where the home public land mobile network HPLMN selects to access an untrusted non-3GPP network, selecting a first non-3GPP interworking function N3IWF entity of the untrusted non-3GPP network supporting the HPLMN slice from the access network discovery and selection policy ANDSP according to the HPLMN slice; Send a registration request to the first N3IWF entity.

2. The method according to claim 1, further comprising: In case that the access public land mobile network VPLMN selects to access an untrusted non-3GPP network, querying a VPLMN slice having a mapping relationship with the HPLMN slice; A second N3IWF entity of an untrusted non-3GPP network supporting the VPLMN slice is selected from the ANDSP.

3. The method according to claim 2, further comprising: Send a registration request to the second N3IWF entity.

4. The method according to any one of claims 1 to 3, further comprising: During access to the HPLMN core network, a first ANDSP message sent by the HPLMN device is received, wherein the first ANDSP message includes a first N3IWF entity identifier of a non-trusted non-3GPP network within the HPLMN and HPLMN slice information supported by the first N3IWF entity.

5. The method according to claim 4, further comprising: During the process of accessing the HPLMN core network, a second ANDSP information sent by the HPLMN device is received, wherein the second ANDSP information includes a second N3IWF entity identifier of a non-trusted non-3GPP network within each VPLMN of multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity, and according to the roaming agreement between each VPLMN and the HPLMN, the VPLMN slice can be mapped to the HPLMN slice subscribed by the user terminal.

6. The method according to claim 4, wherein: The HPLMN device is a policy control function PCF entity in the HPLMN.

7. A user terminal, comprising: The first processing module is configured to select, when the home public land mobile network HPLMN selects to access an untrusted non-3GPP network, a first non-3GPP interworking function N3IWF entity of the untrusted non-3GPP network supporting the HPLMN slice from the access network discovery and selection policy ANDSP according to the HPLMN slice; The second processing module is configured to send a registration request to the first N3IWF entity.

8. The user terminal according to claim 7, wherein: The first processing module is configured to query a VPLMN slice that has a mapping relationship with the HPLMN slice when accessing a public land mobile network VPLMN and choosing to access an untrusted non-3GPP network, and select a second N3IWF entity of the untrusted non-3GPP network that supports the VPLMN slice from the ANDSP.

9. The user terminal according to claim 8, wherein: The second processing module is configured to send a registration request to the second N3IWF entity.

10. The user terminal according to any one of claims 7 to 9, wherein: The first processing module is configured to receive a first ANDSP message sent by the HPLMN device during access to the HPLMN core network, wherein the first ANDSP message includes a first N3IWF entity identifier of a non-trusted non-3GPP network within the HPLMN and HPLMN slice information supported by the first N3IWF entity.

11. The user terminal according to claim 10, wherein: The first processing module is configured to receive second ANDSP information sent by the HPLMN device during access to the HPLMN core network, wherein the second ANDSP information includes a second N3IWF entity identifier of a non-trusted non-3GPP network within each VPLMN of multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity, and according to the roaming agreement between each VPLMN and the HPLMN, the VPLMN slice can be mapped to the HPLMN slice subscribed by the user terminal.

12. The user terminal according to claim 11, wherein: The HPLMN device is a PCF entity in the HPLMN.

13. A user terminal, comprising: a memory configured to store instructions; A processor is coupled to the memory, and the processor is configured to execute the method according to any one of claims 1 to 6 based on instructions stored in the memory.

14. A communication system comprising: A user terminal as claimed in any one of claims 7 to 13; The N3IWF entity is configured to send the registration request to a core network device after receiving the registration request sent by the user terminal; The core network device is configured to perform registration processing according to the registration request so that the user terminal can access the slice after successful registration.

15. The system of claim 14, wherein: The system further comprises: The HPLMN device is configured to select, during the process of the user terminal accessing the HPLMN core network, an HPLMN slice supported by a first N3IWF entity of a non-trusted non-3GPP network in the HPLMN, from among the HPLMN slices subscribed by the user terminal, and send first ANDSP information to the user terminal, wherein the first ANDSP information includes the first N3IWF entity identifier and the HPLMN slice information supported by the first N3IWF entity.

16. The system of claim 15, wherein: The HPLMN device is also configured to send a second ANDSP message to the user terminal during the process of the user terminal accessing the HPLMN core network, wherein the second ANDSP information includes a second N3IWF entity identifier of a non-trusted non-3GPP network within each VPLMN of multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity, and according to the roaming agreement between each VPLMN and the HPLMN, the VPLMN slice can be mapped to the HPLMN slice subscribed by the user terminal.

17. The system of claim 16, wherein: The HPLMN device is also configured to obtain, based on a roaming agreement between itself and the multiple VPLMNs, a second N3IWF entity identifier of a non-trusted non-3GPP network within each of the multiple VPLMNs and VPLMN slice information supported by the second N3IWF entity.

18. The system of claim 17, wherein: The HPLMN device is a PCF entity in the HPLMN; The core network device is an AMF entity.

19. A non-transitory computer-readable storage medium, wherein: The computer-readable storage medium stores computer instructions, and when the instructions are executed by a processor, the method according to any one of claims 1 to 6 is implemented.

20. A computer program product, comprising computer instructions, wherein when the computer instructions are executed by a processor, the method according to any one of claims 1 to 6 is implemented.

Images