Method and apparatus for selecting network slice admission control function

Abstract

The present disclosure provides a network slice admission control function selection method and device, and relates to the field of communication. The technical scheme of the present application is mainly that a network device selects a network slice admission control function (NSACF) based on service area information of the NSACF. The NSACF is selected by considering the service area information of the NSACF, so that a suitable NSACF can be selected more accurately with less signaling and function interaction.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of mobile communication technology, and in particular, to a method and apparatus for selecting a network slice admission control function (NSACF). BACKGROUND

[0002] Network slicing technology allows operators to provide various customized networks, for example, to provide networks with different functional requirements, or networks with different performance requirements, such as different latency, mobility, availability, reliability, and data rate bandwidth requirements; or to provide network functions only for specific users, such as multimedia system users, public safety users, corporate customers, roamers, or mobile virtual network operator hosting.

[0003] Currently, network functions (NFs) usually use a network repository function (NRF) to perform discovery and selection. However, how to select a suitable NSACF so that the monitoring and statistical execution function of the number of network slice UEs and the monitoring and statistical execution function of the number of slice sessions are more easily implemented, such as less signaling interaction, fewer function switches caused by UE mobility, and optimized function execution, is still a key problem to be solved. SUMMARY

[0004] The present disclosure provides a method and apparatus for selecting a NSACF, which can more accurately and with less signaling and function interaction select a suitable NSACF.

[0005] The first aspect of the present disclosure provides a method for selecting a NSACF, the method being performed by a network device, and the method comprising: selecting a NSACF for a network slice based on service area information of the NSACF.

[0006] Optionally, the network device is an access and mobility management function (AMF).

[0007] Optionally, the service area information comprises any one or more of the following: a list of tracking area identities; AMF service area information.

[0008] Optionally, the selecting a NSACF for a network slice comprises: if there is a NSACF that has been selected for the network slice and the service area information of the NSACF indicates that the selected NSACF can be used for the network slice, maintaining the selected NSACF selected for the network slice.

[0009] Optionally, the selecting the NSACF for the network slice comprises: if there are multiple NSACFs have been selected for the network slice and service area information of the multiple NSACFs indicates that the selected multiple NSACFs can be used for the network slice, selecting the NSACF for the network slice from the selected multiple NSACFs.

[0010] Optionally, the selecting the NSACF for the network slice from the selected multiple NSACFs comprises: selecting the NSACF for the network slice from the selected multiple NSACFs based on service capabilities of the NSACF; wherein the service capabilities comprise at least one of: a first service capability of supporting monitoring a number of registered user equipment (UE) of the network slice, and a second service capability of supporting monitoring a number of created protocol data unit (PDU) sessions of the network slice.

[0011] Optionally, the selecting the NSACF for the network slice comprises: if there are one or more NSACFs have been selected for the network slice and service area information of the one or more NSACFs indicates that none of the selected one or more NSACFs should be used for the network slice, selecting a NSACF not belonging to the selected one or more NSACFs for the network slice.

[0012] Optionally, if there is an operator service area policy, the selecting the NSACF for the network slice comprises: selecting the NSACF for the network slice according to service area information of the NSACF and the operator service area policy; wherein the operator service area policy comprises specific rules formulated by an operator for performing NSACF selection based on the service area information.

[0013] Optionally, the operator service area policy is pre-configured in at least one of the network device and a network repository function (NRF).

[0014] Optionally, the selecting the NSACF for the network slice comprises: selecting the NSACF for the network slice from registered NSACFs of the NRF, wherein the NRF stores configuration information of the registered NSACFs, the configuration information comprising network slice selection assistance information (S-NSSAI) and service area information of the registered NSACFs.

[0015] Optionally, the selecting the NSACF for the network slice comprises: selecting the NSACF for the network slice from pre-configured NSACFs of the network device, wherein the network device stores configuration information of the pre-configured NSACFs, the configuration information comprising network slice selection assistance information (S-NSSAI) and service area information of the registered NSACFs.

[0016] Optionally, the method further comprises: receiving, from the UE, a registration request message, wherein the registration request message is triggered in a UE registration procedure or an AMF relocation procedure, and the registration request message carries S-NSSAIs and a UE identifier.

[0017] Optionally, the method further comprises: sending, to the selected NSACF, a UE number validity check and update request message, wherein the UE number validity check and update request message comprises the S-NSSAIs, the UE identifier, and an update flag, and the update flag indicates an increase in the number of registered UEs; and receiving, from the selected NSACF, a UE number validity check and update response message, and performing UE registration according to the UE number validity check and update response message.

[0018] Optionally, the performing UE registration according to the UE number validity check and update response message comprises: if the UE number validity check and update response message indicates that the validity check is successful, performing a UE registration procedure or an AMF relocation procedure and returning a registration accept message to the UE after the UE registration procedure or the AMF relocation procedure is completed; and if the UE number validity check and update response message indicates that the validity check fails, returning a registration reject message to the UE.

[0019] Optionally, when the network device is an AMF, the method further comprises: receiving a deregistration request from the UE, wherein the deregistration request carries S-NSSAIs and a UE identifier; after a UE deregistration procedure is completed according to the deregistration request, sending, to a NSACF that has selected a network slice for the S-NSSAIs, a UE number validity check and update request, wherein the UE number validity check and update request comprises the S-NSSAIs, the UE identifier, and an update flag, and the update flag indicates a decrease in the number of registered UEs; and receiving, from the selected NSACF, a UE number validity check and update response message.

[0020] A second aspect embodiment of the present disclosure provides a selection apparatus of a NSACF, the apparatus being applied to a network device, and the apparatus comprising: a processing module configured to select a NSACF for a network slice based on service area information of the NSACF.

[0021] Optionally, the network device is an access and mobility management function (AMF).

[0022] Optionally, the service area information comprises any one or more of the following: a tracking area identifier list; AMF service area information.

[0023] Optionally, the processing module is configured to maintain the selected NSACF selected for the network slice if there is one NSACF selected for the network slice and the service area information of the NSACF indicates that the selected NSACF can be used for the network slice.

[0024] Optionally, the processing module is configured to select a NSACF for the network slice from the selected multiple NSACFs if there are multiple NSACFs selected for the network slice and the service area information of the multiple NSACFs indicates that the selected multiple NSACFs can be used for the network slice.

[0025] Optionally, the processing module is configured to select a NSACF for the network slice from the selected multiple NSACFs based on service capabilities of the NSACFs; wherein the service capabilities comprise at least one of a first service capability of supporting monitoring of a number of registered user equipment (UE) of the network slice and a second service capability of supporting monitoring of a number of created protocol data unit (PDU) sessions of the network slice.

[0026] Optionally, the processing module is configured to select a NSACF for the network slice that does not belong to the selected one or more NSACFs if there is one or more NSACF selected for the network slice and the service area information of the one or more NSACFs indicates that none of the selected one or more NSACFs should be used for the network slice.

[0027] Optionally, if there is an operator service area policy, the processing module is configured to select a NSACF for the network slice according to the service area information of the NSACF and the operator service area policy; wherein the operator service area policy comprises specific rules formulated by an operator for performing NSACF selection based on the service area information.

[0028] Optionally, the operator service area policy is pre-configured in at least one of the network device and a network repository function (NRF).

[0029] Optionally, the processing module is configured to select a NSACF for the network slice from registered NSACFs of a NRF, wherein the NRF stores configuration information of the registered NSACFs, and the configuration information comprises network slice selection assistance information (S-NSSAI) and service area information of the registered NSACFs.

[0030] Optionally, the processing module is configured to select the NSACF for the network slice from pre-configured NSACFs of the network device, wherein the network device stores configuration information of the pre-configured NSACFs, and the configuration information comprises network slice selection assistance information (S-NSSAIs) and service area information of the registered NSACFs.

[0031] Optionally, the apparatus further comprises a transceiver module configured to receive a registration request message from a UE, wherein the registration request message is triggered in a UE registration procedure or an AMF relocation procedure, and the registration request message carries S-NSSAIs and a UE identifier; and the processing module is configured to select a NSACF for a network slice after the transceiver module receives the registration request message.

[0032] Optionally, the transceiver module is further configured to send a UE number validity check and update request message to the selected NSACF, wherein the UE number validity check and update request message comprises the S-NSSAIs, the UE identifier, and an update flag, and the update flag indicates an increase in the number of registered UEs; and receive a UE number validity check and update response message from the selected NSACF; and the processing module is further configured to perform UE registration according to the UE number validity check and update response message.

[0033] Optionally, the processing module is further configured to, if the UE number validity check and update response message indicates that the validity check is successful, perform a UE registration procedure or an AMF relocation procedure and instruct the transceiver module to return a registration accept message to the UE after the UE registration procedure or the AMF relocation procedure is completed; and if the UE number validity check and update response message indicates that the validity check fails, instruct the transceiver module to return a registration reject message to the UE.

[0034] Optionally, the apparatus further comprises a transceiver module configured to receive a deregistration request from a UE, wherein the deregistration request carries S-NSSAIs and a UE identifier; and after a UE deregistration procedure is completed according to the deregistration request, send a UE number validity check and update request to a NSACF selected for the network slice identified by the S-NSSAIs, wherein the UE number validity check and update request comprises the S-NSSAIs, the UE identifier, and an update flag, and the update flag indicates a decrease in the number of registered UEs; and receive a UE number validity check and update response message from the selected NSACF.

[0035] A third aspect embodiment of the present disclosure provides a communication device, comprising: a transceiver; a memory; a processor connected with the transceiver and the memory respectively, configured to control the transceiver to transceive wireless signals by executing computer executable instructions on the memory, and capable of implementing the NSACF selection method of the first aspect embodiment.

[0036] A fourth aspect embodiment of the present disclosure provides a computer storage medium, wherein the computer storage medium stores computer executable instructions; the computer executable instructions are executed by a processor, and capable of implementing the NSACF selection method of the first aspect embodiment.

[0037] The embodiments of the present disclosure provide a NSACF selection method and device, a network device selects a NSACF for a network slice based on service area information of the NSACF, selects the NSACF by considering the service area information of the NSACF, and can more accurately and with less signaling and function interaction select a suitable NSACF.

[0038] Additional aspects and advantages of the present disclosure will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0039] The above and / or additional aspects and advantages of the present disclosure will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0040] Figure 1 A flowchart of a NSACF selection method according to an embodiment of the present disclosure;

[0041] Figure 2 A flowchart of a NSACF selection method according to an embodiment of the present disclosure;

[0042] Figure 3 A flowchart of a NSACF selection method according to an embodiment of the present disclosure;

[0043] Figure 4 A flowchart of a NSACF selection method according to an embodiment of the present disclosure;

[0044] Figure 5 A flowchart of a NSACF selection method according to an embodiment of the present disclosure;

[0045] Figure 6 A flowchart of a NSACF selection method according to an embodiment of the present disclosure;

[0046] Figure 7A flowchart of a selection method of an NSACF according to an embodiment of the present disclosure;

[0047] Figure 8 An interaction process for selection of an NSACF, validity check and update of a registered UE number according to an embodiment of the present disclosure;

[0048] Figure 9 An interaction process for selection of an NSACF, validity check and update of a registered UE number according to an embodiment of the present disclosure;

[0049] Figure 10 An interaction process for validity check and update of a registered UE number according to an embodiment of the present disclosure in a UE deregistration scenario;

[0050] Figure 11 A structure diagram of a selection device of an NSACF according to an embodiment of the present disclosure;

[0051] Figure 12 A structure diagram of a selection device of an NSACF according to an embodiment of the present disclosure;

[0052] Figure 13 A structure diagram of a communication device according to an embodiment of the present disclosure;

[0053] Figure 14 A structure diagram of a chip according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0054] Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. Examples of the embodiments are shown in the drawings, in which the same or similar components have the same or similar reference numerals throughout. The embodiments described below are exemplary and are intended to explain the present disclosure, and should not be understood as limiting the present disclosure.

[0055] Network slicing technology allows operators to provide various customized networks, for example, if there are differences between functional requirements (e.g., priority, charging, policy control, security, and mobility), if there are differences between performance requirements (e.g., delay time, mobility, availability, reliability, and data speed), or only for specific users (e.g., multimedia system users, public safety users, corporate customers, roamers, or mobile virtual network operator hosting), services can be provided.

[0056] A network slice can provide complete network functionality, including radio access network functionality, core network functionality, and IP Multimedia System (IMS) functionality, among others. A network can support one or more network slices. There are differences between network slices due to the supported network functionality and performance differences. A network slice instance refers to an instantiation of a network slice, i.e., a deployed set of network functions that deliver the intended network slice service according to a network slice template.

[0057] The features and network functionality supported by each network slice can differ, and each network slice can have different Single-Network Slice Selection Assistance Information (S-NSSAI) to identify different slice or service types, which have different slice / service types.

[0058] An operator can deploy multiple network slices for different groups or categories of UEs that provide the same functionality, e.g., to deliver different traffic characteristics or to provide user-specific networks. The slices in such scenarios can be of the same type but are identified with different S-NSSAIs.

[0059] The selection of a set of network slice instances for a UE is typically triggered by the first Access and Mobility Management Function (AMF) in the registration procedure, which interacts with the Network Slice Selection Function (NSSF). The slice selection can result in a reselection of the AMF. A Protocol Data Unit (PDU) session is attributed to and only to one specific network slice instance within a Public Land Mobile Network (PLMN). Although different network slice instances can have PDU sessions of a specific slice that use the same DNN, different network slice instances do not share the same PDU session. During handover, the source AMF selects the target AMF by interacting with the NF Repository Function (NRF).

[0060] Network Slice Type (NEST) is applied to a network slice, and one network slice can deploy multiple network slice instances. A Generic Network Slice Template (GST) defines the attributes supported by a network slice. For example, 1) the number of terminals, which describes the maximum number of terminals that can use the network slice at the same time; 2) the number of connections, which describes the maximum number of concurrent sessions supported by the network slice. This is an important input for determining the size of the network slice and providing sufficient resources for the network slice.

[0061] A network slice can support a limited number of user equipment (UE) using the network slice at the same time and a limited number of concurrent session numbers. In order to support the control of the number of terminals and the number of protocol data unit (PDU) sessions for a network slice, a network slice admission control function (NSACF) is introduced in the 5G communication system. For a network slice subject to network slice admission and control (NSAC), the NSACF monitors the number of registered UEs for each network slice and the number of PDU sessions for each network slice.

[0062] Multiple NSACFs or multiple NSACF instances can be deployed in a network. In an operator network, different NSACF deployment schemes can be included as follows. One network slice deploys multiple NSACFs. Or multiple NSACFs serve multiple network slices of one large network for flexibility. A single or multiple NSACFs are dedicated to a certain specific network slice to provide customized services, such as isolated slices. In addition, when multiple network slice instances are deployed in one network slice, the above schemes can also be implemented.

[0063] For NSACF discovery and selection, a network function (NF) usually uses a network repository function (NRF) to perform. For the discovery and selection of NSACF, the discovery end network function can be performed through the NRF, or can be performed through local configuration and other operator policies. This scheme is suitable for the discovery and selection of NSACF functions or NSACF instances. However, how to more accurately and with less signaling select a suitable NSACF makes it more beneficial to the implementation of the network slice UE number monitoring and statistical execution function and the slice session number monitoring and statistical execution function, such as less signaling interaction or function interaction, support and optimization of function execution, which is still a key problem to be solved.

[0064] Multiple NSACFs can be deployed in a PLMN, but how to select a suitable NSACF more accurately and with fewer signaling interactions or functional interactions is still a key problem to be solved.

[0065] Therefore, the purpose of the present disclosure is to select a suitable NSACF in consideration of factors such as the need for NSACF per area, to select a suitable NSACF with less signaling, such as less transmission of network slice status notification and reporting or NF device relocation, and to select a suitable NSACF with higher accuracy.

[0066] The present disclosure provides a method and apparatus for selecting a NSACF, in which a network device selects a NSACF for a network slice based on service area information of the NSACF. By considering the service area information of the NSACF, a suitable NSACF can be selected more accurately and with fewer signaling and functional interactions.

[0067] The method and apparatus for selecting a NSACF provided by the present disclosure will be described in detail below with reference to the accompanying drawings.

[0068] Figure 1 A flowchart of a method for selecting a NSACF according to an embodiment of the present disclosure is shown. As shown in the figure, the method can be performed by a network device. The method can include the following steps. Figure 1

[0069] S101, selecting a NSACF for a network slice based on service area information of the NSACF.

[0070] Since multiple NSACFs can be deployed in a network such as a PLMN, there is currently a lack of effective technical means for how to select a suitable NSACF from a large number of NSACFs.

[0071] Therefore, the present disclosure provides a method for selecting a NSACF, in which a network device selects a NSACF for a network slice based on service area information of the NSACF.

[0072] It should be noted that when the deployed NSACF has multiple NSACF instances, the method for selecting a NSACF of the present embodiment is also applicable, i.e., a NSACF instance can be selected based on the service area information of the NSACF instance, and the specific details are not repeated here.

[0073] In some embodiments, the network device can be an access and mobility management function (AMF, Access and Mobility Management Function).

[0074] ​The AMF can select a NSACF for a network slice for monitoring the number of registered UEs for the network slice.

[0075] In some embodiments, in case the network device is an AMF, the service area information can comprise any one or more of: a list of tracking area identities; AMF service area information.

[0076] The service area information of the NSACF can comprise a list of tracking area identities (TAIs), and the AMF can select a NSACF for a network slice based on the list of TAIs of the NSACF. A tracking area (TA) is defined as a free mobility area for which a user equipment (UE) does not need to update the service. A TA is a cell level configuration, multiple cells can be configured with the same TA, and a cell can only belong to one TA. A TAI is an identity of a TA, which consists of a PLMN and a tracking area code (TAC). Multiple TA can form a list of TA, which is assigned to a UE at the same time, and the UE does not need to perform a TA update when moving within the list of TA to reduce frequent interaction with the network. When the UE enters a new TA which is not in the list of TA it is registered to, a TA update needs to be performed, and thus the UE is assigned a new list of TA. For example, in case of UE registration, the AMF needs to select a NSACF for a corresponding network slice (e.g. identified by S-NSSAIs included in a registration request from the UE), and if the service area information of the NSACF comprises a list of TAIs, the AMF can select a NSACF based on the list of TAIs of the NSACF for monitoring the number of registered UEs for the network slice, and the list of TAIs of the selected NSACF comprises, for example, the identities of the TA in the list of TA assigned to the UE.

[0077] Further, in case the service area information of the NSACF comprises a list of TAIs, different NSACFs have different list of TAIs. For example, for a plurality of NSACF functions or NSACF instances deployed in a network which can be used for a certain area, there can be a list of TAIs of a number of NSACF functions or instances which comprises TA that can cover the whole area, while other list of TAIs of other NSACF functions or instances only comprises TA that can cover part of the area respectively, i.e. there can be a list of TAIs of a number of NSACF functions or instances which is a TAI list 1 corresponding to the whole area, while other list of TAIs of other NSACF functions or instances are subsets of the TAI list 1 respectively.

[0078] The service area information of the NSACF can comprise AMF service area information, and the AMF selects the NSACF for a network slice based on the AMF service area information possessed by the NSACF. For example, in the case of UE registration, the AMF needs to select the NSACF for the corresponding network slice (for example, identified by S-NSSAIs included in the registration request from the UE), and if the service area information of the NSACF comprises the AMF service area information, the AMF can select the NSACF based on the AMF service area information possessed by the NSACF to monitor the number of registered UEs of the network slice, and the selected NSACF possesses the AMF service area information of the AMF, for example.

[0079] According to the NSACF selection method of the present embodiment, the network device can select the NSACF for the network slice based on the service area information of the NSACF, and by considering the service area information of the NSACF, a suitable NSACF can be selected more accurately with less signaling and functional interaction.

[0080] Figure 2 A flowchart of a method for selecting a NSACF according to an embodiment of the present disclosure is shown, which can be performed by a network device, as shown in Figure 2 The method can comprise the following steps.

[0081] S201, selecting a NSACF for a network slice based on service area information of the NSACF.

[0082] In some embodiments, the network device can be an AMF.

[0083] In some embodiments, the service area information can comprise any one or more of the following: a list of tracking area identities; AMF service area information.

[0084] For specific details of S201, reference can be made to step S101 and related descriptions in Figure 1 , which will not be repeated here.

[0085] In the present embodiment, the above step S201 can comprise any one of the following steps.

[0086] S2011, if there is a NSACF that has been selected for the network slice and the service area information of the NSACF indicates that the selected NSACF can be used for the network slice, maintaining the selected NSACF selected for the network slice.

[0087] In the case that the network device selects the NSACF for the network slice, there is a case that there is already one NSACF selected for the network slice, for example, due to that the NSACF has been selected for the corresponding network slice in the registration procedure of a certain UE, then in the case of registration of another UE, if the S-NSSAIs carried in the registration request of the another UE still identify the network slice, the above-mentioned case can occur.

[0088] In this case, if the service area information of the selected NSACF indicates that it can be used for the network slice, the network device still selects the NSACF for monitoring the number of registered UEs of the network slice, that is, maintains the selected NSACF for the network slice.

[0089] For example, as shown in the embodiments with reference to Figure 1 For example, as shown in the embodiments with reference to

[0090] S2012, if there are multiple NSACFs already selected for the network slice and the service area information of the multiple NSACFs indicates that the selected multiple NSACFs can be used for the network slice, select the NSACF for the network slice from the selected multiple NSACFs.

[0091] In the case that the network device selects the NSACF for the network slice, there is a case that there are multiple NSACFs already selected for the network slice.

[0092] In this case, if the service area information of the selected multiple NSACFs indicates that the selected multiple NSACFs can be used for the network slice, the network device can select the NSACF for monitoring the number of registered UEs of the network slice from the selected multiple NSACFs.

[0093] In some embodiments, the above-mentioned step S2012 can include the following steps:

[0094] S20121, select the NSACF for the network slice from the selected multiple NSACFs based on the service capability of the NSACF.

[0095] The service capabilities include at least one of a first service capability of supporting monitoring of a number of registered user equipment (UE) of the network slice and a second service capability of supporting monitoring of a number of created PDU session of the network slice.

[0096] The NSACF can have a plurality of different service capabilities, for example, the NSACF can have a service capability of only supporting monitoring of a number of registered UE of the network slice, or the NSACF can have a service capability of only supporting monitoring of a number of created PDU session of the network slice, or the NSACF can have a service capability of both supporting monitoring of a number of registered UE of the network slice and supporting monitoring of a number of created PDU session of the network slice. If the selection of the NSACF is directly performed without considering the service capability of the NSACF, it is possible to select the NSACF that does not meet the requirement, for example, in the case of UE registration, if the AMF directly selects the NSACF for the network slice without considering the service capability of the NSACF, it is possible to select the NSACF that does not have the service capability of supporting monitoring of a number of registered UE of the network slice, that is, the NSACF that does not meet the requirement.

[0097] Therefore, when the network device selects the NSACF for the network slice from the selected plurality of NSACFs, the selection of the NSACF can also be performed by considering the service capability of the NSACF.

[0098] Specifically, in the case of the network device being the AMF, the AMF can select the NSACF with the service capability of only supporting monitoring of a number of registered UE of the network slice or the NSACF with the service capability of both supporting monitoring of a number of registered UE of the network slice and supporting monitoring of a number of created PDU session of the network slice from the selected plurality of NSACFs for the network slice, for monitoring the number of registered UE of the network slice.

[0099] S2013, if one or more NSACFs have been selected for the network slice and the service area information of the one or more NSACFs indicates that the selected one or more NSACFs should not be used for the network slice, selecting the NSACF that does not belong to the selected one or more NSACFs for the network slice.

[0100] As described above, when the network device selects the NSACF for the network slice, there is a case that one or more NSACFs have been selected for the network slice.

[0101] In this case, if the service area information of the selected one or more NSACFs indicates that none of the selected one or more NSACFs should be used for the network slice, the network device selects a new NSACF for the network slice to monitor the number of registered UEs in the network slice. This new NSACF does not belong to the selected one or more NSACFs.

[0102] For example, as referenced Figure 1 As shown in the embodiments, when the network device is an AMF, if the service area information of one or more NSACFs is a TAI list, and the TAI list of each of the selected one or more NSACFs does not include the identifier of the TA in the TA list assigned to the UE requesting to monitor the network slice, it indicates that the selected one or more NSACFs are not suitable for the network slice, and the AMF selects a new, more suitable NSACF for monitoring the number of registered UEs in the network slice. Similarly, if the service area information of one or more NSACFs is AMF service area information, and the AMF service area information of each of the selected one or more NSACFs is not the service area information of that AMF, it indicates that the selected one or more NSACFs are not suitable for the network slice, and the AMF selects a new, more suitable NSACF for monitoring the number of registered UEs in the network slice.

[0103] According to the NSACF selection method of this implementation, network devices can select NSACFs for network slicing by considering the service area information of the selected NSACFs when an existing NSACF has been selected for network slicing. This allows for more accurate selection of a suitable NSACF with less signaling and function interaction.

[0104] Figure 3 A flowchart illustrating an NSACF selection method according to an embodiment of this disclosure is shown. This method can be executed by a network device, such as... Figure 3 As shown, the method may include the following steps.

[0105] S301 selects NSACF for network slices based on NSACF service area information.

[0106] In some embodiments, the network device may be an AMF.

[0107] In some embodiments, when the network device is an AMF, the service area information may include one or more of the following: a list of tracking area identifiers; AMF service area information.

[0108] For specific details about the S301, please refer to [link / reference]. Figure 1The related description of step S101 in the method is not repeated here.

[0109] In this embodiment, when the operator service area policy is available, the NSACF for the network slice can be further selected by the following steps.

[0110] S3011, selecting the NSACF for the network slice according to the service area information of the NSACF and the operator service area policy.

[0111] The operator service area policy includes specific rules formulated by the operator for performing the NSACF selection based on the service area information.

[0112] In this embodiment, when the operator service area policy is available, the network device selects the NSACF for the network slice based on the operator service area policy and the service area information of the NSACF, so that the selected NSACF can meet the operator service area policy.

[0113] In the case of the network device being an AMF, the operator service area policy can include one or more of a TAI list, a policy priority of the service area information of the AMF, one or more tracking area information in the service area information of the AMF, a priority of each NSACF with a service capability of supporting monitoring the number of registered UEs of the network slice, location information of a UE requesting a service of monitoring the registered UEs of the network slice, registration tracking area information of the UE requesting the service of monitoring the number of registered UEs of the network slice, and the like.

[0114] It should be noted that the operator service area policy listed here is only an example, and in actual applications, each operator can formulate various different operator service area policies according to its own needs, which are not limited in the present application.

[0115] As mentioned in the foregoing embodiments, the network device can be an AMF, an SMF, a UDM, a PCF, a UPF, or the like. Figure 1In some embodiments, the operator service area policy is preconfigured in at least one of the network device and the NRF.

[0116] In some embodiments, the operator service area policy is preconfigured in at least one of the network device and the NRF.

[0117] The operator service area policy can be preconfigured in the network device or in the NRF. When the operator service area policy is preconfigured in the NRF, the network device can access the NRF to obtain the operator service area policy.

[0118] In some embodiments, if there is one NSACF has been selected for the network slice and both the service area information of the NSACF and the operator service area policy indicate that the selected NSACF can be used for the network slice, the network device maintains the selected NSACF selected for the network slice.

[0119] For example, when the service area information of the selected NSACF is a TAI list and the operator service area policy is to select the NSACF having the TAI list completely matching the TA list of the UE requesting the service of monitoring the number of registered UEs of the network slice, if the TAI list of the selected NSACF completely matches the TA list allocated to the UE, it indicates that the selected NSACF can be used for the network slice, and the network device maintains the selected NSACF for monitoring the number of registered UEs of the network slice.

[0120] In some embodiments, if there are multiple NSACFs selected for the network slice and the service area information and the operator service area policy of the NSACF both indicate that the selected multiple NSACFs can be used for the network slice, the network device selects a NSACF for the network slice from the selected multiple NSACFs. Specifically, the network device can select a NSACF for the network slice from the selected multiple NSACFs based on the service capability of the NSACF, and the related details can be referred to the related description of step S2012 in Figure 2 .

[0121] In some embodiments, if there is one or more NSACF selected for the network slice but the service area information or the operator service area policy of the NSACF indicates that each of the selected NSACF should not be used for the network slice, the network device selects a NSACF not belonging to the selected one or more NSACF for the network slice based on the operator service area policy and the service area information of the NSACF.

[0122] For example, in the case of the network device being an AMF, when the service area information of the selected one or more NSACFs is a TAI list and the operator service area policy is to select the NSACF having the TAI list completely matching the TA list of the UE requesting the service of monitoring the number of registered UEs of the network slice, if the TAI list of each of the selected one or more NSACFs does not include the identity of the TA in the TA list allocated to the UE requesting the service of monitoring the number of registered UEs of the network slice, or if the TAI list of part of the selected one or more NSACFs includes the identity of the TA in the TA list allocated to the UE but does not completely match the TA list allocated to the UE, it indicates that the selected one or more NSACFs are not suitable NSACFs for the network slice, and the AMF selects a new more suitable NSACF for the network slice for monitoring the number of registered UEs of the network slice.

[0123] According to the selection method of the NSACF of the present embodiment, if there is an operator service area policy, the network device will select a NSACF based on the service area information of the NSACF according to the operator service area policy, so that the selected NSACF can meet the operator service area policy.

[0124] Figure 4 A flowchart of a method of selecting an NSACF is shown according to an embodiment of the disclosure. The method can be performed by a network device, such as an AMF. Figure 4 As shown, the method can include the following steps.

[0125] S401, selecting an NSACF for a network slice based on service area information of the NSACF.

[0126] In some embodiments, the network device can be an AMF.

[0127] In some embodiments, when the network device is an AMF, the service area information can include any one or more of the following: a list of tracking area identities; AMF service area information.

[0128] For specific details of S401, refer to the related description of step S101 in Figure 1 , which will not be repeated here.

[0129] In the present embodiment, the above step S401 can include any of the following steps.

[0130] S4011, selecting an NSACF for a network slice from registered NSACFs in the NRF. The NRF stores configuration information of the registered NSACFs, and the configuration information includes S-NSSAIs and service area information of the registered NSACFs.

[0131] The NSACF can be registered in the NRF, and the NSACF provides its configuration information to the NRF, and the NRF marks that the NSACF is available. In the registration process of the NSACF, the NSACF provides S-NSSAIs and service area information of the NSACF, that is, the configuration information of the NSACF registered in the NRF can include S-NSSAIs and service area information thereof. The network device can use the NRF to discover and select the NSACF.

[0132] The S-NSSAIs can include a plurality of S-NSSAIs, and an S-NSSAI identifies a network slice, which is auxiliary information used by the network to select a specific network slice instance. The S-NSSAI can include the following information: slice / service type (SST), indicating different functional and service network slices; slice differentiator, optional information used to further distinguish the supplementary SST of the network slice instance from all network slice instances that meet the SST type.

[0133] In some embodiments, the network device selects an NSACF for a network slice from the registered NSACFs in the NRF based on service area information of the NSACF.

[0134] The specific details about how the network device selects the NSACF based on the service area information of the NSACF can refer to the related description of step S101 in Figure 1 , and will not be described here again.

[0135] In some embodiments, if there is one or more NSACFs that have been selected for the network slice and the service area information of the one or more NSACFs indicates that none of the selected one or more NSACFs should be used for the network slice, the network device selects, based on the service area information of the NSACF, a NSACF that does not belong to the selected one or more NSACFs for the network slice from the registered NSACFs in the NRF.

[0136] The specific details about how the network device selects the NSACF that does not belong to the selected one or more NSACFs in this case can refer to the related description of step S2013 in Figure 2 , and will not be described here again.

[0137] In some embodiments, when there is an operator service area policy, the network device selects the NSACF from the registered NSACFs in the NRF according to the service area information of the NSACF and the operator service area policy. If there is one or more NSACFs that have been selected for the network slice and the service area information of the one or more NSACFs or the operator service area policy indicates that none of the selected one or more NSACFs should be used for the network slice, the network device selects, based on the service area information of the NSACF and the operator service area policy, a NSACF that does not belong to the selected one or more NSACFs for the network slice from the registered NSACFs in the NRF.

[0138] The specific details about how the network device selects the NSACF based on the service area information of the NSACF and the operator service area policy can refer to the related description of step S3011 in Figure 3 , and will not be described here again.

[0139] S4012, selecting the NSACF from the pre-configured NSACFs of the network device, wherein the network device stores the configuration information of the pre-configured NSACF, and the configuration information includes S-NSSAIs and the service area information of the registered NSACF.

[0140] The NSACF can be locally configured in the network device, and the configuration information of the NSACF can indicate the service area information of the NSACF and the S-NSSAIs. The network device can use the configuration information to discover and select the NSACF.

[0141] In some embodiments, the network device selects the NSACF from the preconfigured NSACFs of the network device based on the service area information of the NSACF.

[0142] For details about how the network device selects the NSACF based on the service area information of the NSACF, refer to the related description of step S101 in Figure 1 , which will not be repeated here.

[0143] In some embodiments, if there is one or more NSACF has been selected for the network slice and the service area information of the one or more NSACF indicates that none of the selected one or more NSACF should be used for the network slice, the network device selects, for the network slice, a NSACF not belonging to the selected one or more NSACF from the preconfigured NSACFs of the network device based on the service area information of the NSACF.

[0144] For details about how the network device selects the NSACF not belonging to the selected one or more NSACF in this case, refer to the related description of step S2013 in Figure 2 , which will not be repeated here.

[0145] In some embodiments, when there is an operator service area policy, the network device selects the NSACF from the preconfigured NSACFs of the network device according to the service area information of the NSACF and the operator service area policy. If there is one or more NSACF has been selected for the network slice and the service area information of the one or more NSACF or the operator service area policy indicates that none of the selected one or more NSACF should be used for the network slice, the network device selects, for the network slice, a NSACF not belonging to the selected one or more NSACF from the preconfigured NSACFs of the network device based on the service area information of the NSACF and the operator service area policy.

[0146] For details about how the network device selects the NSACF based on the service area information of the NSACF and the operator service area policy, refer to the related description of step S3011 in Figure 3 , which will not be repeated here.

[0147] According to the NSACF selection method of the present embodiment, the network device can select the corresponding NSACF from the NRF or from the local preference, thereby avoiding a complex NSACF selection process and reducing signaling transmission.

[0148] Figure 5 Fig. 1 shows a flowchart of a method for selecting a NSACF according to an embodiment of the present disclosure, which can be performed by a network device. As shown in Fig. 1, the method can include the following steps. Figure 5

[0149] ​S501, selecting a NSACF for a network slice based on service area information of the NSACF.

[0150] In some embodiments, the network device can be an AMF.

[0151] In some embodiments, when the network device is an AMF, the service area information can include any one or more of the following: a list of tracking area identities; AMF service area information.

[0152] For specific details of S501, please refer to the relevant description of step S101 in Figure 1 , which will not be repeated here.

[0153] In this embodiment, the NSACF for the network slice can be selected by the following steps.

[0154] S5011, selecting a NSACF for a network slice after receiving a registration request message from a UE, wherein the registration request message is triggered in a UE registration procedure or an AMF relocation procedure, and the registration request message carries S-NSSAIs and a UE identity.

[0155] In this embodiment, after receiving a registration request message from a UE, the AMF can determine whether to perform monitoring of the number of registered UEs for a corresponding network slice, and select a NSACF for the network slice to monitor the number of registered UEs for the network slice when it is determined that the number of registered UEs for the network slice needs to be monitored.

[0156] When a UE registers to a network, the AMF can receive a registration request message from the UE, which carries S-NSSAIs and a UE identity. If the S-NSSAI carried in the registration request is included in the Allowed NSSAI of the AMF, the AMF will select a NSACF based on the service area information of the NSACF.

[0157] When AMF relocation is performed, the AMF can receive a registration request message from a UE requesting AMF service from another AMF (which can be an AMF that previously served the UE), which carries S-NSSAIs and a UE identity. If the S-NSSAI carried in the registration request is included in the Allowed NSSAI of the AMF, the AMF will select a NSACF based on the service area information of the NSACF.

[0158] For specific details of selecting a NSACF for a network slice, please refer to steps S101, Figure 1 in Figure 2 steps S201 and S2011-S2013,Figure 3 the related description of steps S301 and S3011 in Figure 4 the related description of steps S401 and S4011-S4012 in

[0159] According to the selection method of the NSACF of the embodiment, the network device can perform selection of the NSACF in response to a registration request message from the UE.

[0160] Figure 6 A flowchart of a method for selecting a NSACF is shown according to an embodiment of the disclosure, which can be performed by an AMF, as shown in Figure 6 The method can include the following steps.

[0161] S601, selecting a NSACF for a network slice after receiving a registration request message from a UE, wherein the registration request message is triggered in a UE registration procedure or an AMF relocation procedure, and the registration request message carries S-NSSAIs and a UE identifier.

[0162] For specific details of S601, refer to the related description of step S5011 in Figure 5

[0163] S602, sending a UE number validity check and update request message to the selected NSACF, wherein the UE number validity check and update request message includes S-NSSAIs, a UE identifier, and an update flag, and the update flag indicates an increase in the number of registered UEs.

[0164] After the AMF selects the NSACF, the AMF can send a UE number validity check and update request message to the selected NSACF, so that the NSACF can perform a check of the number of registered UEs according to the UE number validity check and update request message.

[0165] S603, receiving a UE number validity check and update response message from the selected NSACF, and performing UE registration according to the UE number validity check and update response message.

[0166] After the NSACF receives the UE number validity check and update request message, the NSACF performs a check of the number of registered UEs in response to the UE number validity check and update request message, and updates the number of registered UEs and / or feeds back a UE number validity check and update response message according to the check result. After the AMF receives the UE number validity check and update response message, the AMF can perform UE registration according to the response message.

[0167] In some embodiments, the above step S603 can include the following steps.

[0168] ​S6031, if the UE number validity check and update response message indicates that the validity check is successful, performing a UE registration procedure or an AMF relocation procedure and returning a registration accept message to the UE after the UE registration procedure or the AMF relocation procedure is completed.

[0169] In the case of UE registration, if the UE number validity check and update response message indicates that the validity check is successful, it indicates that the UE can be registered to the corresponding network slice, and then the AMF performs a UE registration procedure based on the UE number validity check and update response message and returns a registration accept message to the UE after the UE registration procedure is completed.

[0170] In the case of AMF relocation, if the UE number validity check and update response message indicates that the validity check is successful, it indicates that the UE can be registered to the corresponding network slice, and then the AMF performs an AMF relocation procedure based on the UE number validity check and update response message and returns a registration accept message to the UE after the AMF relocation procedure is completed.

[0171] S6032, if the UE number validity check and update response message indicates that the validity check fails, returning a registration reject message to the UE.

[0172] In the case of UE registration, if the UE number validity check and update response message indicates that the validity check fails, it indicates that the UE cannot be registered to the corresponding network slice, for example, because the number of UE registrations of the network slice has reached the maximum number, and then the AMF returns a registration reject message to the UE based on the UE number validity check and update response message.

[0173] In the case of AMF relocation, if the UE number validity check and update response message indicates that the validity check fails, it indicates that the UE cannot be registered to the corresponding network slice, for example, because the number of UE registrations of the network slice has reached the maximum number, and then the AMF returns a registration reject message to the UE based on the UE number validity check and update response message.

[0174] According to the method for selecting the NSACF, the AMF can perform monitoring of the number of registered UEs of the corresponding network slice through the NSACF after selecting the NSACF.

[0175] Figure 7 A flowchart of a method for selecting a NSACF according to an embodiment of the disclosure is shown, which can be performed by an AMF, as shown in Figure 7 The method can include the following steps.

[0176] S701, selecting a NSACF for a network slice based on service area information of the NSACF.

[0177] In some embodiments, the service area information can comprise any one or more of: a list of tracking area identities; AMF service area information.

[0178] For specific details of S701, please refer to the related description of steps S101, Figure 1 S201 and S2011-S2013 in Figure 2 S301 and S3011 in Figure 3 S401 and S4011-S4012 in Figure 4 S501 and S5011 in Figure 5 S601, which will not be repeated here. Figure 6

[0179] S702, receiving a deregistration request from the UE, wherein the deregistration request carries S-NSSAIs and UE identity.

[0180] When the UE deregisters, the UE can send a deregistration request to the AMF, which can carry the UE identity and S-NSSAIs.

[0181] S703, after completing the UE deregistration process according to the deregistration request, sending an effectiveness check and update request to the NSACF identified for the S-NSSAIs, the effectiveness check and update request including S-NSSAIs, UE identity and update flag, wherein the update flag indicates to reduce the number of registered UEs.

[0182] After receiving the deregistration request from the UE, the AMF can perform the UE deregistration process, and after the UE deregistration process is completed, find the NSACF identified for the network slice selection of the S-NSSAI included in the deregistration request, and send an effectiveness check and update request message to the found NSACF, so that the NSACF can perform the check of the number of registered UEs according to the effectiveness check and update request message.

[0183] S704, receiving an effectiveness check and update response message from the selected NSACF.

[0184] ​After receiving the validity check and update request message, the NSACF performs a check on the number of registered UEs in response to the validity check and update request message, and performs updating and / or feeding back of the number of registered UEs and a validity check and update response message according to the check result. In this embodiment, since the update flag in the validity check and update request indicates a reduction in the number of registered UEs, the NSACF reduces the number of registered UEs according to the update flag, and feeds back the validity check and update response message to the AMF after completing the reduction of the number of registered UEs. After receiving the validity check and update response message, the AMF can confirm that the NSACF has performed updating of the number of registered UEs of the corresponding network slice according to the validity check and update response message.

[0185] According to the selection method of the NSACF, the AMF can select the NSACF, and perform monitoring of the number of registered UEs of the corresponding network slice through the NSACF after selecting the NSACF.

[0186] Figure 8 An interaction process for selection of the NSACF, validity check and updating of the number of registered UEs according to an embodiment of the present disclosure is shown. As shown in Figure 8 the AMF selects the NSACF, and interacts with the NSACF to implement validity check and updating of the number of registered UEs. Specifically, the following processes are included.

[0187] S801, triggering validity check and updating of the number of registered UEs.

[0188] The validity check and updating of the number of registered UEs can be triggered in response to a message received by the AMF from other devices, or can be triggered by the AMF based on a certain preset triggering mechanism.

[0189] For example, the validity check and update on the number of registered UEs can be triggered in response to a registration request information from a UE. In the case of UE registration, the AMF can perform the selection of NSACF based on the service area information of NSACF carried in the PDU session creation request. The service area information of NSACF can include a list of tracking area identities; one or more of the AMF service area information. In performing the selection of NSACF, if there is one NSACF selected for the network slice and the service area information of NSACF indicates that the selected NSACF can be used for the network slice, the AMF still selects the selected NSACF for the network slice for monitoring the number of registered UEs for the network slice. If there are multiple NSACFs selected for the network slice and the service area information of the multiple NSACFs indicates that the selected multiple NSACFs can be used for the network slice, the AMF selects a NSACF from the selected multiple NSACFs for the network slice for monitoring the number of registered UEs for the network slice, e.g., the AMF selects a NSACF from the selected multiple NSACFs for the network slice for monitoring the number of registered UEs for the network slice based on the service capability of NSACF. In addition, if there is an operator service area policy, the AMF selects a NSACF for the network slice for monitoring the number of registered UEs for the network slice according to the service area information of NSACF and the operator service area policy. The selection of NSACF can be performed at UE registration or AMF relocation. In addition, the selection method of NSACF described in this document is also applicable to the selection of NSACF instance.

[0190] The NSACF can be registered in the NRF, and the NSACF provides its configuration information to the NRF, and the NRF marks that the NSACF is available. For the PDU session creation procedure, the NSACF can provide S-NSSAIs and the service area information of NSACF as input information. If the NSACF is registered in the NRF, the AMF can utilize the NRF to select the NSACF.

[0191] The NSACF can be configured in the AMF, and the configuration information of NSACF can indicate the service area information of NSACF and S-NSSAIs. If the NSACF is configured in the AMF, the AMF can utilize the configuration information of NSACF in the AMF to select the NSACF.

[0192] The operator service capability policy can be pre-configured in the AMF and / or the NRF.

[0193] In another example, the validity check and update on the number of registered UEs can be triggered in response to the AMF completing a UE deregistration procedure.

[0194] In another example, in case of AMF relocation (i.e. handover from old AMF to new AMF), the new AMF can receive the Allowed NSSAI of the old AMF from the old AMF. If one or more S-NSSAI in the Allowed NSSAI of the old AMF is not supported by the new AMF, i.e. not included in the Allowed NSSAI of the new AMF, the new AMF will send a status update request message to the old AMF for the old AMF to perform status update. The status update message includes the one or more S-NSSAI not supported by the new AMF. Upon receiving the status update message, the old AMF sends a validity check and update request message to the NSACF selected for the corresponding network slice carrying an update flag indicating to reduce the number of registered UEs, so that the NSACF reduces the number of registered UEs for the network slice.

[0195] S802, if the S-NSSAI is confirmed to be included in the Allowed NSSAI of the AMF, the AMF sends a validity check and update request message to the selected NSACF.

[0196] The validity check and update request (Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request) message includes the UE identity, S-NSSAI and update flag. The update flag can indicate to increase the number of registered UEs when the UE is to be registered to the corresponding network slice or to reduce the number of registered UEs when the UE is to be deregistered from the corresponding network slice or the UE restarts to register to another network slice.

[0197] S803, the NSACF performs the check and update of the number of registered UEs based on the validity check and update request message provided by the AMF.

[0198] If the update flag in the validity check and update request message indicates to increase the number of registered UEs and the NSACF finds that the UE identity in the validity check and update request message already exists in the registered UE list of the corresponding network slice, the NSACF will not increase the number of registered UEs, because the UE has already been counted as registered to the corresponding network slice.

[0199] If the update flag in the validity check and update request message indicates to increase the number of registered UEs and the NSACF finds that the UE identity in the validity check and update request message does not exist in the registered UE list of the corresponding network slice and the number of registered UEs for the corresponding network slice has not reached the maximum number, the NSACF will add the UE identity to the registered UE list and increase the number of registered UEs.

[0200] If the update flag in the validity check and update request message indicates to increase the registered UE number and the NSACF finds that the UE identity in the validity check and update request message does not exist in the registered UE list of the corresponding network slice and the registered UE number of the corresponding network slice has reached the maximum number, the NSACF will not increase the registered UE number and will return a result parameter indicating that the registered UE number of the corresponding network slice has reached the maximum number.

[0201] If the update flag in the validity check and update request message indicates to decrease the registered UE number, the NSACF will remove the UE identity in the validity check and update request message from the registered UE list of the corresponding network slice and decrease the registered UE number.

[0202] S804, the NSACF feeds back the validity check and update response message to the AMF.

[0203] When the NSACF finds that the registered UE number of the corresponding network slice has reached the maximum number, the validity check and update response (Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response) message fed back by the NSACF to the AMF can include the result parameter as described above.

[0204] In the case of UE registration, if the NSACF feeds back a result parameter indicating that the registered UE number of the network slice has reached the maximum number for all S-NSSAIs in the registration request information, the AMF will reject the registration request information of the UE and return a registration rejection message to the UE, and if the NSACF does not feed back a result parameter indicating that the registered UE number of the network slice has reached the maximum number for a certain S-NSSAI in the registration request information, the AMF will perform the UE registration process and return a registration acceptance message to the UE after completing the UE registration process. In the registration rejection message or the registration acceptance message, for example, the rejected S-NSSAIs, the rejection reason (such as "the registered UE number of the corresponding network slice has reached the maximum number") and the optional backoff time are included.

[0205] For example, Figure 9 An interaction process for the selection of the NSACF, the validity check and update of the registered UE number in the case of UE registration according to an embodiment of the present disclosure is shown. As shown in Figure 9 The AMF selects the NSACF and interacts with the NSACF to implement the validity check and update of the registered UE number. Specifically, the following processes are included.

[0206] S901, the UE sends a registration request (Registration Request) to the AMF, the registration request including S-NSSAIs and UE identity.

[0207] S902, the AMF considers S-NSSAIs carried in the registration request, and selects NSACF based on service area information of the NSACF.

[0208] In the case of UE registration, the AMF can consider S-NSSAIs carried in the PDU session creation request and perform selection of NSACF based on service area information of the NSACF. The service area information of the NSACF can include one or more of a list of tracking area identities; a subset of the list of tracking area identities; and service area information of the AMF. In performing the selection of the NSACF, if there is one NSACF that has been selected for a network slice and the service area information of the NSACF indicates that the selected NSACF can be used for the network slice, the AMF still selects the selected NSACF for the network slice for monitoring the number of registered UEs of the network slice. If there are multiple NSACFs that have been selected for a network slice and the service area information of the multiple NSACFs indicates that the selected multiple NSACFs can be used for the network slice, the AMF selects a NSACF from the selected multiple NSACFs for the network slice for monitoring the number of registered UEs of the network slice, for example, the AMF selects a NSACF from the selected multiple NSACFs for the network slice for monitoring the number of registered UEs of the network slice based on service capabilities of the NSACFs. In addition, if there is an operator service area policy, the AMF selects a NSACF for the network slice for monitoring the number of registered UEs of the network slice according to the service area information of the NSACF and the operator service area policy. The selection of the NSACF can be performed at UE registration or AMF relocation. In addition, the selection method of the NSACF described herein is also applicable to the selection of NSACF instances.

[0209] The NSACF can be registered in the NRF, and the NSACF provides its configuration information to the NRF, and the NRF marks that the NSACF is available. For the PDU session creation procedure, the NSACF can provide S-NSSAIs and service area information of the NSACF as input information. If the NSACF is registered in the NRF, the AMF can use the NRF to select the NSACF.

[0210] The NSACF can be configured in the AMF, and the configuration information of the NSACF can indicate the service area information of the NSACF and S-NSSAIs. If the NSACF is configured in the AMF, the AMF can use the configuration information of the NSACF in the AMF to select the NSACF.

[0211] The operator service capability policy can be preconfigured in the AMF and / or the NRF.

[0212] S903, if the S-NSSAI is confirmed to be included in the Allowed NSSAI of the AMF, the AMF sends a validity check and update request (Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request) message to the selected NSACF.

[0213] S904, the NSACF performs checking and updating of the number of registered UEs based on the validity check and update request message provided by the AMF.

[0214] S905, the NSACF feeds back a validity check and update response (Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response) message to the AMF.

[0215] S906, the AMF performs UE registration according to the validity check and update response message, specifically, S906 can include step S906a or steps S906b-S906c.

[0216] S906a, the AMF rejects the registration request of the UE and returns a registration rejection (Registration Reject) message to the UE.

[0217] S906b, the AMF performs the UE registration procedure.

[0218] S906c, the AMF returns a registration acceptance (Registration Accept) message to the UE after completing the UE registration procedure.

[0219] Further, as shown in FIG. 10, Figure 10 FIG. 10 shows an interaction process for validity checking and updating of the number of registered UEs in the case of UE deregistration according to an embodiment of the present disclosure, which is based on that the UE has registered to a network slice, and the UE or the network triggers the deregistration procedure. As shown in FIG. 10, Figure 10 The AMF and the NSACF interact to implement the validity checking and updating of the number of registered UEs. Specifically, the following processes are included.

[0220] S1001a, the UE sends a deregistration request (Deregistration Request) to the AMF, which includes S-NSSAIs and a UE identifier.

[0221] S1001b, the AMF performs the UE deregistration procedure.

[0222] S1001c, after completing the UE deregistration process, the AMF returns a DeregistrationAccept message to the UE.

[0223] S1002, if the S-NSSAI carried in the deregistration request is confirmed to be included in the AMF's Allowed NSSAI, the AMF sends a validity check and update request (Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Request) message to the selected NSACF.

[0224] S1003, NSACF performs a check and update of the number of registered UEs based on the validity check and update request message provided by AMF.

[0225] S1004, NSACF sends a validity check and update response (Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate_Response) message to AMF.

[0226] The methods provided in the embodiments of this application above are described from the perspective of a network device. To implement the functions of the methods provided in the embodiments of this application above, the network device may include hardware structures and software modules, implementing the above functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. One of the above functions can be executed in the form of hardware structures, software modules, or a combination of hardware structures and software modules.

[0227] Corresponding to the NSACF selection methods provided in the above embodiments, this disclosure also provides an NSACF selection device. Since the NSACF selection device provided in this disclosure corresponds to the NSACF selection methods provided in the above embodiments, the implementation of the NSACF selection methods is also applicable to the NSACF selection device provided in this embodiment, and will not be described in detail in this embodiment.

[0228] Figure 11 This is a schematic diagram of the structure of an NSACF selection device 1100 provided in an embodiment of this disclosure.

[0229] like Figure 11 As shown, the device 1100 can be applied to network equipment, and the device 1100 may include a processing module 1601. The processing module 1601 can be configured to select an NSACF for network slices based on NSACF service area information.

[0230] According to the selection apparatus of the NSACF, the network device selects the NSACF for the network slice based on the service area information of the NSACF, and the NSACF is selected by considering the service area information of the NSACF, so that a suitable NSACF can be selected more accurately and with less signaling and function interaction.

[0231] In some embodiments, the network device can be an AMF.

[0232] In some embodiments, when the network device is an AMF, the service area information includes any one or more of the following: a tracking area identity list; AMF service area information.

[0233] In some embodiments, the processing module 1101 is configured to maintain the selected NSACF selected for the network slice if there is one NSACF that has been selected for the network slice and the service area information of the NSACF indicates that the selected NSACF can be used for the network slice.

[0234] In some embodiments, the processing module 1101 is configured to select an NSACF for the network slice from the selected multiple NSACFs if there are multiple NSACFs that have been selected for the network slice and the service area information of the multiple NSACFs indicates that the selected multiple NSACFs can be used for the network slice.

[0235] In some embodiments, the processing module 1101 is configured to select an NSACF for the network slice from the selected multiple NSACFs based on service capabilities of the NSACFs; and the service capabilities include at least one of the following: a first service capability of supporting monitoring of a number of registered user equipment (UE) of the network slice, and a second service capability of supporting monitoring of a number of created protocol data unit (PDU) sessions of the network slice.

[0236] In some embodiments, the processing module 1101 is configured to select an NSACF for the network slice that does not belong to the selected one or more NSACFs if there is one or more NSACFs that have been selected for the network slice and the service area information of the one or more NSACFs indicates that none of the selected one or more NSACFs should be used for the network slice.

[0237] In some embodiments, if there is an operator service area policy, the processing module 1101 is configured to select an NSACF for the network slice according to the service area information of the NSACF and the operator service area policy; and the operator service area policy includes specific rules formulated by an operator for performing NSACF selection based on the service area information.

[0238] Optionally, the operator service area policy is pre-configured in at least one of the network device and a network repository function (NRF).

[0239] In some embodiments, the processing module 1101 is configured to select a NSACF for the network slice from the registered NSACFs in the NRF, wherein the configuration information of the registered NSACFs is stored in the NRF, and the configuration information comprises network slice selection assistance information (S-NSSAIs) and service area information of the registered NSACFs.

[0240] In some embodiments, the processing module 1101 is configured to select a NSACF for the network slice from the pre-configured NSACFs of the network device, wherein the configuration information of the pre-configured NSACFs is stored in the network device, and the configuration information comprises network slice selection assistance information (S-NSSAIs) and service area information of the registered NSACFs.

[0241] In some embodiments, as shown in Figure 12 The apparatus 1100 further includes a transceiver module 1102. The transceiver module 1102 can be configured to receive a registration request message from a UE, wherein the registration request message is triggered in a UE registration procedure or an AMF relocation procedure, and the registration request message carries S-NSSAIs and a UE identifier; and the processing module 1101 is configured to select a NSACF for a network slice after the transceiver module 1102 receives the registration request message.

[0242] In some embodiments, the transceiver module 1102 is further configured to send a UE number validity check and update request message to the selected NSACF, wherein the UE number validity check and update request message comprises the S-NSSAIs, the UE identifier, and an update flag, and the update flag indicates an increase in the number of registered UEs; and receive a UE number validity check and update response message from the selected NSACF; and the processing module 1101 is further configured to perform UE registration according to the UE number validity check and update response message.

[0243] In some embodiments, the processing module 1101 is further configured to, if the UE number validity check and update response message indicates that the validity check is successful, perform a UE registration procedure or an AMF relocation procedure and instruct the transceiver module 1102 to return a registration accept message to the UE after the UE registration procedure or the AMF relocation procedure is completed; and if the UE number validity check and update response message indicates that the validity check fails, instruct the transceiver module 1102 to return a registration reject message to the UE.

[0244] In some embodiments, the transceiver module 1102 is configured to receive a deregistration request from a UE, wherein the deregistration request carries S-NSSAIs and a UE identifier; after completing the UE deregistration procedure according to the deregistration request, send a UE number validity check and update request to a selected NSACF for the S-NSSAIs, the UE number validity check and update request including the S-NSSAIs, the UE identifier, and an update flag, wherein the update flag indicates a decrease in the number of registered UEs; and receive a UE number validity check and update response message from the selected NSACF.

[0245] See Figure 13 , Figure 13 is a structural schematic diagram of a communication apparatus 1300 provided by an embodiment of the present application. The communication apparatus 1300 can be a network device, can be a user equipment, can be a chip, a chip system, or a processor supporting the network device to implement the method described above, and can also be a chip, a chip system, or a processor supporting the terminal device to implement the method described above. The apparatus can be used to implement the method described in the method embodiment described above, and specific reference can be made to the description in the method embodiment described above.

[0246] The communication apparatus 1300 can include one or more processors 1301. The processor 1301 can be a general-purpose processor or a special-purpose processor, etc. For example, it can be a baseband processor or a central processor. The baseband processor can be used to process communication protocols and communication data, and the central processor can be used to control the communication apparatus (such as a base station, a baseband chip, a terminal device, a terminal device chip, a DU or a CU, etc.), execute a computer program, and process data of the computer program.

[0247] Optionally, the communication apparatus 1300 can further include one or more memories 1302, which can have a computer program 1304 stored thereon. The processor 1301 executes the computer program 1304 to enable the communication apparatus 1300 to perform the method described in the method embodiment described above. Optionally, the memory 1302 can also store data. The communication apparatus 1300 and the memory 1302 can be separately arranged or integrated together.

[0248] Optionally, the communication apparatus 1300 can further include a transceiver 1305, an antenna 1306. The transceiver 1305 can be referred to as a transceiving unit, a transceiver, or a transceiving circuit, etc., and is used to implement the transceiving function. The transceiver 1305 can include a receiver and a transmitter. The receiver can be referred to as a receiver or a receiving circuit, etc., and is used to implement the receiving function. The transmitter can be referred to as a transmitter or a transmitting circuit, etc., and is used to implement the transmitting function.

[0249] Optionally, the communication device 1300 may further include one or more interface circuits 1307. The interface circuits 1307 are used to receive code instructions and transmit them to the processor 1301. The processor 1301 executes the code instructions to cause the communication device 1300 to perform the methods described in the above method embodiments.

[0250] Communication device 1300 is a network device: processor 1301 is used to execute Figure 1 Step S101 in Figure 2 Steps S201 and S2011-S2013 in the process Figure 3 Steps S301 and S3011 in the process Figure 4 Steps S401 and S4011-S4012 in the process Figure 5 Steps S501 and S5011 in the process Figure 6 Steps S601, S603, and S6031 in the process Figure 7 Step S701; transceiver 1305 is used to perform Figure 6 Steps S602-S603 and S6031-S6032 in the process Figure 7 Steps S702-S704 in the process.

[0251] In one implementation, the processor 1301 may include a transceiver for implementing receive and transmit functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing receive and transmit functions may be separate or integrated. The aforementioned transceiver circuit, interface, or interface circuit can be used for reading and writing code / data, or it can be used for transmitting or relaying signals.

[0252] In one implementation, processor 1301 may store computer program 1303, which runs on processor 1301 and causes communication device 1300 to perform the methods described in the above method embodiments. Computer program 1303 may be embedded in processor 1301, in which case processor 1301 may be implemented in hardware.

[0253] In an implementation, the communication apparatus 1300 can include circuitry that can implement the functions of transmitting or receiving or communicating in the foregoing method embodiments. The processor and transceiver described in the present application can be implemented on an integrated circuit (IC), an analog IC, a radio frequency integrated circuit (RFIC), a mixed-signal IC, an application specific integrated circuit (ASIC), a printed circuit board (PCB), an electronic device, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductor (CMOS), N-type metal oxide semiconductor (NMOS), positive channel metal oxide semiconductor (PMOS), bipolar junction transistor (BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0254] The communication apparatus in the above embodiments can be a network device or a terminal device (such as the first terminal device in the foregoing method embodiments), but the scope of the communication apparatus described in the present application is not limited thereto, and the structure of the communication apparatus can not be limited by Figure 13 The communication apparatus can be a standalone device or can be part of a larger device. For example, the communication apparatus can be:

[0255] (1) a standalone integrated circuit (IC), or a chip, or a chip system or subsystem;

[0256] (2) a set of one or more ICs, optionally including storage components for storing data, computer programs, etc.

[0257] (3) an ASIC, such as a modem;

[0258] (4) a module that can be embedded in other devices;

[0259] (5) a receiver, a terminal device, a smart terminal device, a cellular phone, a wireless device, a handset, a mobile unit, a car-mounted device, a network device, a cloud device, an artificial intelligence device, etc.

[0260] (6) other, etc.

[0261] For the case that the communication device can be a chip or a chip system, refer to Figure 14 a structural diagram of the chip. Figure 14 The chip shown includes a processor 1401 and an interface 1402. Among them, the number of processors 1401 can be one or more, and the number of interfaces 1402 can be multiple.

[0262] For the case that the chip is used to implement the functions of the network device in the embodiments of the present application: the processor 1401 is configured to perform Figure 1 step S101, Figure 2 steps S201 and S2011-S2013 in Figure 3 steps S301 and S3011 in Figure 4 steps S401 and S4011-S4012 in Figure 5 steps S501 and S5011 in Figure 6 steps S601, S603 and S6031 in Figure 7 step S701 in ; the interface 1402 is configured to perform Figure 6 steps S602-S603 and S6031-6032 in Figure 7 steps S702-S704 in .

[0263] Optionally, the chip further includes a memory 1403, and the memory 1403 is configured to store necessary computer programs and data.

[0264] Those skilled in the art can also understand that the various illustrative logical blocks and steps listed in the embodiments of the present application can be implemented by electronic hardware, computer software, or a combination of the two. Whether the function is implemented by hardware or software depends on the specific application and design requirements of the overall system. Those skilled in the art can use various methods to implement the described functions for each specific application, but such implementation should not be understood as beyond the scope of the embodiments of the present application.

[0265] The present application also provides a readable storage medium having instructions stored thereon, which, when executed by a computer, implement the functions of any of the above method embodiments.

[0266] The present application also provides a computer program product which, when executed by a computer, implements the functions of any of the above method embodiments.

[0267] In the embodiments described above, all or some of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or some of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer programs. When loaded and executed by a computer, all or some of the embodiments generate the processes or functions described in the embodiments of the present application. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer program can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer program can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode. The computer readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. containing one or more available media. The available media can be magnetic media (such as floppy disk, hard disk, magnetic tape), optical media (such as high-density digital video disc (digital video disc, DVD)), or semiconductor media (such as solid state disk (solid state disk, SSD)) and the like.

[0268] Those of ordinary skill in the art can understand that various numbers such as first, second, etc. involved in the present application are only distinguished for the convenience of description, and do not limit the scope of the embodiments of the present application, nor represent the order of precedence.

[0269] At least one of the present application can also be described as one or more, and the plurality can be two, three, four or more, which is not limited in the present application. In the embodiments of the present application, for a technical feature, the technical features in the technical feature are distinguished by "first", "second", "third", "A", "B", "C" and "D", and there is no order or size order between the technical features described by "first", "second", "third", "A", "B", "C" and "D".

[0270] As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, apparatus and / or device (e.g., magnetic discs, optical discs, memory, programmable logic devices (PLDs)) used to provide machine instructions and / or data to a programmable processor, including a machine-readable medium that receives the machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0271] The systems and techniques described here can be implemented in a computing system that includes a back end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front end component, e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here, or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN), a wide area network (WAN), and the Internet.

[0272] The computer system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

[0273] It should be understood that the various forms of flow shown in the above figures can be re-ordered, added to, or deleted from, without departing from the scope of the present disclosure. For example, the steps recited in the present disclosure can be performed in parallel, in series, or in different orders, as long as the desired results of the present disclosure are achieved, and are not limited herein.

[0274] In addition, it should be understood that various embodiments described herein can be implemented either alone or in combination with other embodiments where the solutions permit.

[0275] Those skilled in the art can realize that the units and algorithm steps of the examples described in connection with the embodiments disclosed herein can be realized in electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solutions. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0276] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be described here.

[0277] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for selecting a Network Slice Admission Control Function (NSACF), characterized in that, The method is performed by a network device, and the method comprises: after receiving a registration request message from a UE, selecting a NSACF for a network slice based on service area information of the NSACF, wherein the registration request message is triggered in a UE registration procedure or an AMF relocation procedure, and the registration request message carries S-NSSAIs and a UE identifier; the service area information comprises any one or more of the following: a tracking area identifier list; AMF service area information; sending a UE number validity check and update request message to the selected NSACF, wherein the UE number validity check and update request message comprises the S-NSSAIs, the UE identifier, and an update flag, and the update flag indicates an increase in the number of registered UEs; and receiving a UE number validity check and update response message from the selected NSACF; if the UE number validity check and update response message indicates that the validity check is successful, performing a UE registration procedure or an AMF relocation procedure and returning a registration accept message to the UE after completing the UE registration procedure or the AMF relocation procedure; and if the UE number validity check and update response message indicates that the validity check fails, returning a registration reject message to the UE; wherein the selecting of the NSACF for the network slice comprises: if there is one or more NSACFs that have been selected for the network slice and the service area information of the one or more NSACFs indicates that none of the selected one or more NSACFs should be used for the network slice, selecting a NSACF that does not belong to the selected one or more NSACFs for the network slice; if there are multiple NSACFs that have been selected for the network slice and the service area information of the multiple NSACFs indicates that the selected multiple NSACFs can be used for the network slice, selecting a NSACF for the network slice from the selected multiple NSACFs based on service capabilities of the NSACF, wherein the service capabilities comprise at least one of the following: a first service capability of monitoring the number of registered user equipment (UE) of the network slice, and a second service capability of monitoring the number of created protocol data unit (PDU) sessions of the network slice.

2. The method of claim 1, wherein, The network device is an access and mobility management function (AMF).

3. The method of any one of claims 1-2, wherein, The selecting of the NSACF for the network slice further comprises: if there is one NSACF that has been selected for the network slice and the service area information of the NSACF indicates that the selected NSACF can be used for the network slice, maintaining that the selected NSACF is selected for the network slice.

4. The method of any one of claims 1-2, wherein, If there is an operator service area policy, the selecting of the NSACF for the network slice further comprises: selecting a NSACF for the network slice according to the service area information of the NSACF and the operator service area policy; wherein the operator service area policy comprises specific rules formulated by an operator for performing NSACF selection based on the service area information.

5. The method of claim 4, wherein, The operator service area policy is preconfigured in at least one of the network device and a network repository function (NRF).

6. The method of any one of claims 1-2, wherein, The selecting of the NSACF for the network slice further comprises: selecting a NSACF for the network slice from registered NSACFs of the NRF, wherein the NRF stores configuration information of the registered NSACFs, the configuration information comprising network slice selection assistance information S-NSSAIs and service area information of the registered NSACFs.

7. The method of any one of claims 1-2, wherein, The selecting a NSACF for the network slice further comprises: selecting a NSACF for the network slice from pre-configured NSACFs of the network device, wherein the network device stores configuration information of the pre-configured NSACFs, the configuration information comprising network slice selection assistance information S-NSSAIs and service area information of the registered NSACFs.

8. The method of any one of claims 1-2, wherein, The method further comprises: receiving a deregistration request from a UE, wherein the deregistration request carries S-NSSAIs and a UE identity; after completing a UE deregistration procedure according to the deregistration request, sending a UE number validity check and update request to a NSACF selected for the S-NSSAIs, the UE number validity check and update request comprising the S-NSSAIs, the UE identity and an update flag, wherein the update flag indicates a decrease in the number of registered UEs; and receiving a UE number validity check and update response message from the selected NSACF. 9.A network slice admission control function (NSACF) selection apparatus, characterized in that, The apparatus is applied to a network device, and the apparatus comprises: a transceiver module configured to receive a registration request message from a UE, wherein the registration request message is triggered in a UE registration procedure or an AMF relocation procedure, and the registration request message carries S-NSSAIs and a UE identity; a processing module configured to, after the transceiver module receives the registration request message, select a NSACF for a network slice based on service area information of the NSACF; the service area information comprises any one or more of the following: a tracking area identity list; AMF service area information; the transceiver module is further configured to send a UE number validity check and update request message to the selected NSACF, the UE number validity check and update request message comprising the S-NSSAIs, the UE identity and an update flag, the update flag indicating an increase in the number of registered UEs; and receive a UE number validity check and update response message from the selected NSACF; and the processing module is further configured to, if the UE number validity check and update response message indicates that the validity check is successful, perform a UE registration procedure or an AMF relocation procedure and instruct the transceiver module to return a registration accept message to the UE after completing the UE registration procedure or the AMF relocation procedure; and if the UE number validity check and update response message indicates that the validity check fails, instruct the transceiver module to return a registration reject message to the UE; the processing module is further configured to: if there are multiple NSACFs selected for the network slice and the service area information of the multiple NSACFs indicates that the selected multiple NSACFs can be used for the network slice, selecting, for the network slice, a NSACF from the selected multiple NSACFs based on service capabilities of the NSACF; wherein the service capabilities comprise at least one of: a first service capability of supporting monitoring of a number of registered user equipment (UE) of the network slice, and a second service capability of supporting monitoring of a number of created protocol data unit (PDU) sessions of the network slice.

10. The apparatus of claim 9, wherein, The network device is an access and mobility management function (AMF).

11. The apparatus of any one of claims 9-10, wherein, The processing module is configured to: if there is one NSACF selected for the network slice and the service area information of the NSACF indicates that the selected NSACF can be used for the network slice, maintain the selected NSACF selected for the network slice.

12. The apparatus of any one of claims 9-10, wherein, if there is an operator service area policy, the processing module is configured to: select, for the network slice, a NSACF according to the service area information of the NSACF and the operator service area policy; wherein the operator service area policy comprises specific rules formulated by an operator for performing NSACF selection based on the service area information.

13. The apparatus of claim 12, wherein, The operator service area policy is preconfigured in at least one of the network device and a network repository function (NRF).

14. The apparatus of any one of claims 9-10, wherein, The processing module is configured to: select, for the network slice, a NSACF from registered NSACFs of the NRF, wherein the NRF stores configuration information of the registered NSACFs, and the configuration information comprises network slice selection assistance information (S-NSSAI) and service area information of the registered NSACF.

15. The apparatus of any one of claims 9-10, wherein, The processing module is configured to: select, for the network slice, a NSACF from preconfigured NSACFs of the network device, wherein the network device stores configuration information of the preconfigured NSACFs, and the configuration information comprises S-NSSAI and service area information of the registered NSACF.

16. The apparatus of any one of claims 9-10, wherein, The apparatus further comprises a transceiver module configured to: receive a deregistration request from a UE, wherein the deregistration request carries S-NSSAIs and a UE identifier; after completing a UE deregistration process according to the deregistration request, send a UE number validity check and update request to a NSACF selected for the network slice identified by the S-NSSAIs, the UE number validity check and update request comprising the S-NSSAIs, the UE identifier, and an update flag, wherein the update flag indicates a decrease in the number of registered UEs; and receive a UE number validity check and update response message from the selected NSACF.

17. A communication device, wherein, comprise: a transceiver; a memory; a processor connected to the transceiver and the memory, respectively, and configured to control wireless signal transmission and reception of the transceiver by executing computer executable instructions on the memory, and capable of implementing the method of any one of claims 1-8.

18. A computer storage medium, wherein, The computer storage medium stores computer executable instructions; the computer executable instructions are executed by the processor, and can implement the method in any one of claims 1-8.

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