A method, apparatus and system for selecting a tracking area

Abstract

Embodiments of the present application provide a method, device and system for selecting a tracking area, which are used to solve the problem of terminal access network slice failure. The method comprises: a mobility management network element initiating an authentication and authorization process for a network slice to be authenticated and authorized in a network slice requested by a terminal, and determining identification information of a network slice allowed to be accessed by the terminal according to a result of the authentication and authorization process; obtaining identification information of a target network slice and wireless resource information corresponding to the target network slice according to the identification information of the network slice allowed to be accessed by the terminal and first information (such as identification information of the network slice requested by the terminal or identification information of a network slice rejected to be accessed by the terminal), and sending the identification information of the target network slice and the wireless resource information corresponding to the target network slice to an access network device, so that the access network device triggers the terminal to successfully access a new network slice supported by a TA according to the identification information of the target network slice and the wireless resource information corresponding to the target network slice.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication technology, and in particular to a method, device and system for selecting a tracking area. BACKGROUND

[0002] A network slice (NS) is a network for supporting logical isolation of specific network capabilities and network characteristics, and is a key technology for network differentiation requirements proposed by the 5th generation (5G) mobile communication technology of the 3rd generation partnership project (3GPP). The network slice can provide mutually isolated network environments for different application scenarios by virtually separating independent logical networks on the same network infrastructure, so that different application scenarios can customize network functions and characteristics according to their own requirements, and the quality of service (QoS) requirements of different services can be effectively guaranteed.

[0003] When a terminal requests to access a network slice, since the terminal blindly selects an access network device, there may be a case that the wireless resources deployed in a tracking area (TA) where the access network device is located do not support the network slice requested by the terminal to access, and thus the network slice access fails. How to select a suitable TA to ensure that the terminal successfully accesses the network slice from the TA becomes a problem to be solved. SUMMARY

[0004] Embodiments of the present application provide a method, device and system for selecting a tracking area, which solve the problem of terminal access failure to a network slice.

[0005] To achieve the above object, embodiments of the present application adopt the following technical solutions:

[0006] In a first aspect, a method for selecting a tracking area is provided. The method includes: a mobility management network element initiating an authentication and authorization procedure for a network slice to be authenticated and authorized by a terminal, determining identity information of a network slice allowed to be accessed by the terminal according to a result of the authentication and authorization procedure of the network slice, obtaining identity information of a target network slice and wireless resource information corresponding to the target network slice according to the identity information of the network slice allowed to be accessed by the terminal and first information, and sending the identity information of the target network slice and the wireless resource information corresponding to the target network slice to an access network device, so that the access network device can successfully access a new TA supporting the target network slice according to the identity information of the target network slice and the wireless resource information corresponding to the target network slice. The first information includes identity information of a network slice rejected to be accessed by the terminal, or identity information of a network slice requested by the terminal. The network slice rejected to be accessed by the terminal is a network slice not supported by a TA where the access network device is located in the network slice requested by the terminal.

[0007] Based on the method of the first aspect, in a scenario where there is a network slice to be authenticated and authorized, after the network slice is authenticated and authorized, identity information of a target network slice is determined according to a result of the authentication and authorization, the accuracy of the network slice determined to be allowed to be accessed by the terminal is ensured, and at the same time, the access network device is notified to select a new TA supporting the target network slice for the terminal, thereby solving the problem of failure of the terminal to access the network slice.

[0008] In a possible design, the mobility management network element obtains the second information according to the identity information of the network slice allowed to be accessed by the terminal and the first information in the following any manner: the mobility management network element determines the second information according to the identity information of the network slice allowed to be accessed by the terminal and the first information. For example, the mobility management network element can determine identity information of a network slice rejected to be accessed by the terminal according to the first information, determine identity information of the target network slice and wireless resource information corresponding to the target network slice according to the identity information of the network slice rejected to be accessed by the terminal and the identity information of the network slice allowed to be accessed by the terminal, and receive the wireless resource information corresponding to the target network slice from a policy control network element. Alternatively, the mobility management network element sends the identity information of the network slice allowed to be accessed by the terminal and the first information to a network slice selection function network element, and receives the second information from the network slice selection function network element.

[0009] Based on the possible design, the second information can be determined by the mobility management network element or by another network element, thereby flexibly and effectively obtaining the second information.

[0010] In a possible design, the mobility management network element can send the second information to the access network device after a terminal registration procedure. In this way, the network side can be notified to select a new TA for the terminal after the terminal completes registration and establishes a connection with the network side, thereby ensuring that a subsequent procedure after network registration is successfully executed.

[0011] In one possible design, the mobility management network element sends the second information to the access network device in any of the following ways: Method 1: If the authentication and authorization process of the network slice to be authenticated and authorized is successful, the mobility management network element initiates a user equipment (UE) configuration update process and sends a first message including a UE configuration update command and the first information to the access network device. That is, in the scenario of successful authentication and authorization, the second information is sent to the access network device through the UE configuration update process, reducing signaling overhead. Method 2: If the authentication and authorization processes of the network slice to be authenticated and authorized all fail, and the identification information of the network slice that the terminal is allowed to access is not empty, the mobility management network element sends a UE context update request carrying the second information to the access network device. Method 3: If the authentication and authorization processes of the network slice to be authenticated and authorized all fail, and the identification information of the network slice that the terminal is allowed to access is empty, the mobility management network element sends a UE context release request carrying the second information to the access network device.

[0012] Based on this possible design, the second information can be sent in different ways depending on the application scenario, ensuring that the second information is sent to the access network device flexibly and effectively, and simplifying the system design.

[0013] In one possible design, the method further includes: the mobility management network element storing first information, that is, pre-storing the first information so that after the authentication and authorization process is completed, the second information can be obtained based on the stored first information and other information (such as the identification information of the network slice that the terminal is allowed to access). That is, by pre-storing the first information, the latency and complexity of obtaining the second information are reduced, and the system design is simplified.

[0014] In one possible design, the method further includes: the mobility management network element storing first indication information, the first indication information being used to indicate one or more of the following: selecting a new tracking area for the terminal, the new tracking area supporting the target network slice; or redirecting the terminal to a tracking area or frequency band supporting the target network slice; or, after the authentication and authorization process, obtaining second information so that the mobility management network element responds to the first indication information and obtains the second information after the authentication and authorization process is completed, thereby determining the identification information of the network slice that the terminal is allowed to access based on the authentication and authorization result, and thus ensuring the accuracy of the identification information of the target network slice determined based on the identification information of the network slice that the terminal is allowed to access and the first information.

[0015] In a possible design, the mobility management network element can determine that the first information or the first indication information needs to be stored in a case where it is determined that the network slice requested by the terminal does not exist in a TA where the access network device is located (or the TA needs to be reselected), and then store the first information or further optionally store the first indication information.

[0016] In a possible design, the method further includes: the mobility management network element can delete the stored first information or the first indication information after obtaining the second information, so as to reduce the cache pressure of the mobility management network element.

[0017] In a second aspect, a communication apparatus is provided for implementing the methods described above. The communication apparatus can be the mobility management network element in the first aspect, or a device including the mobility management network element. The communication apparatus includes modules, units, or means corresponding to the modules, units, or means for implementing the methods described above. The modules, units, or means can be implemented by hardware, software, or by a combination of hardware and software. The hardware or software includes one or more modules or units corresponding to the functions described above. For example, in a possible design, the communication apparatus can include a processing unit, a transceiver unit, and the like.

[0018] The processing unit is configured to: obtain, from the identity information of the network slice requested by the terminal, identity information of a network slice to be authenticated and authorized, initiate an authentication and authorization procedure for the network slice to be authenticated and authorized, determine identity information of a network slice that allows the terminal to access according to a result of the authentication and authorization procedure for the network slice, and obtain second information according to the identity information of the network slice that allows the terminal to access and first information. The first information includes identity information of a network slice that rejects the terminal to access, or identity information of the network slice requested by the terminal. The network slice that rejects the terminal to access is a network slice that is not supported by a TA where the access network device is located in the network slice requested by the terminal.

[0019] The transceiver unit is configured to: send the second information to the access network device. The second information includes identity information of a target network slice and radio resource information corresponding to the target network slice.

[0020] In a third aspect, a communication apparatus is provided, which includes a processor and a memory. The memory is configured to store computer instructions, and the processor is configured to execute the computer instructions to cause the communication apparatus to perform the methods in any of the aspects described above. The communication apparatus can be the mobility management network element in the first aspect, or a device including the mobility management network element.

[0021] In a fourth aspect, a communication apparatus is provided, which comprises a processor; the processor is configured to couple with a memory, and read instructions in the memory, and execute the method in any of the above aspects according to the instructions. The communication apparatus can be the mobility management network element in the first aspect, or an apparatus comprising the mobility management network element.

[0022] In a fifth aspect, a computer readable storage medium is provided, which stores instructions, when executed on a computer, cause the computer to perform the method in any of the above aspects.

[0023] In a sixth aspect, a computer program product is provided, which comprises instructions, when executed on a computer, cause the computer to perform the method in any of the above aspects.

[0024] In a seventh aspect, a communication apparatus (for example, the communication apparatus can be a chip or a chip system) is provided, which comprises a processor, configured to implement the functions in any of the above aspects. In a possible design, the communication apparatus further comprises a memory, configured to store necessary program instructions and data. When the communication apparatus is a chip system, the communication apparatus can be composed of a chip, or comprise a chip and other discrete devices.

[0025] The technical effects brought by any of the designs in the second aspect to the seventh aspect can be referred to the technical effects brought by the different designs in the first aspect, which will not be repeated here.

[0026] In an eighth aspect, a communication system is provided, which comprises a mobility management network element and an access network device; the mobility management network element is configured to acquire, from identification information of network slices requested by a terminal, identification information of network slices to be authenticated and authorized, initiate an authentication and authorization procedure for the network slices to be authenticated and authorized, determine identification information of network slices allowed to be accessed by the terminal according to a result of the authentication and authorization procedure of the network slices, acquire second information according to the identification information of the network slices allowed to be accessed by the terminal and first information, and send the second information to the access network device; the first information comprises identification information of network slices rejected to be accessed by the terminal, or identification information of the network slices requested by the terminal; the network slices rejected to be accessed by the terminal are network slices not supported by a TA where the access network device is located in the network slices requested by the terminal; the access network device is configured to select a new TA for the terminal according to the second information, so that the terminal successfully accesses network slices supported by the new TA on the new TA.

[0027] The technical effects brought by the eighth aspect can be referred to the technical effects brought by the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Schematic diagram of different types of network slicing;

[0029] Figure 2 This is a schematic diagram of the communication system provided in an embodiment of this application;

[0030] Figure 3a One possible embodiment of this application is provided with Figure 2 The diagram shows the network architecture corresponding to the communication system shown.

[0031] Figure 3b One possible embodiment of this application is provided with Figure 2 The diagram shows the network architecture corresponding to the communication system shown.

[0032] Figure 4 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0033] Figure 5 A flowchart illustrating a method for selecting a tracking region provided in an embodiment of this application;

[0034] Figure 6 Interactive illustration of the method for selecting a tracking region provided in the embodiments of this application Figure 1 ;

[0035] Figure 7 Interactive illustration of the method for selecting a tracking region provided in the embodiments of this application Figure 2 ;

[0036] Figure 8 The third interactive diagram illustrates the method for selecting a tracking region provided in this application embodiment.

[0037] Figure 9 Interactive illustration of the method for selecting a tracking region provided in the embodiments of this application Figure 4 ;

[0038] Figure 10 Interactive illustration of the method for selecting a tracking region provided in the embodiments of this application Figure 5 ;

[0039] Figure 11 Interactive illustration of the method for selecting a tracking region provided in the embodiments of this application Figure 6 ;

[0040] Figure 12 This is a schematic diagram of the structure of a communication device 120 provided in an embodiment of this application;

[0041] Figure 13 This is a schematic diagram of the structure of a communication system provided in an embodiment of this application. Detailed Implementation

[0042] In order to facilitate the understanding of the technical solutions of the embodiments of the present application, first, a brief introduction of the related technologies of the present application is given as follows.

[0043] Network slice (NS): a logical network with specific network characteristics, is a key technology to meet the network differentiation requirements of the 5th Generation (5G) mobile communication network proposed by the 3rd Generation Partnership Project (3GPP). The currently defined standard network slice types include mobile broadband (MBB), enhanced mobile broadband (eMBB), ultra-reliable and low-latency communication (URLLC), massive internet of things (MIoT), massive machine type communication (massive MTC), and critical machine type communication (critical MTC). The network characteristics of different network slices are not the same, and the network slices are required to be isolated from each other and not to affect each other. Considering that the performance requirements of various network slices are different, the wireless resources (such as frequency or frequency band) required to access by different network slices may be different. For example, as shown in FIG. 1, there are MBB type network slices, massive MTC type network slices, and critical MTC type network slices, which are isolated from each other and do not affect each other. For the MBB type network slice, the terminal needs to access this type of network slice from 2.6 GHz or 4.9 GHz; and for the MTC type network slice (massive MTC type or critical MTC type), the terminal needs to access this type of network from 2.6 GHz. Figure 1

[0044] Network slice instance (NSI): an instance of a network created by an operator on an infrastructure according to a network slice template, which is composed of different network function entities and physical resource sets. Different network slice instances are logically isolated. One network slice can be instantiated into one or more NSIs, and each NSI is identified by a network slice instance identifier (NSI ID). Network slice instances of different service types can be deployed on different network slices, and different NSIs of the same service type can be deployed on the same or different network slices.​

[0045] Network Slice Selection Assistance Information (NSSAI): NSSAI is used to indicate one or multiple network slices, and the NSSAI can include multiple single network slice selection assistance information (S-NSSAI). One network slice is identified by an S-NSSAI. The S-NSSAI consists of a slice / service type (SST) and a slice differentiator (SD). The SST and the SD can be defined by standards or customized by operators; the SD is optional information that supplements the SST to differentiate multiple network slices with the same SST, and the SD can be used to represent the ownership of the network slice. The types and roles of the NSSAI defined in the 23.501 standard are shown in Table 1.

[0046] It should be noted that in the embodiments of the present application, the S-NSSAI can be referred to as the identification information of one network slice, and the NSSAI can be referred to as the set of identification information of one or multiple network slices.

[0047] Table 1

[0048]

[0049]

[0050] Tracking Area (TA): TA can be location information of a terminal, multiple TAs can form a TA list, and the TA list is assigned to a terminal at the same time, so that the terminal does not need to perform TA update when moving in the TA list, thereby reducing frequent interaction with the network. The TA can be configured at the cell level, multiple cells can be configured with the same TA, and one cell can only belong to one TA. One or multiple network slices can be deployed in one TA. If a network slice is deployed in a TA, all cells in the TA support the network slice, and the terminal can access the network slice from any cell in the TA. The network slice that is not supported by the TA can be described as the TA not supporting the network slice, and the TA not supporting the network slice can be understood as not supporting the terminal to access the network slice through the TA. The correspondence between the TA and the network slice supported by the TA can be pre-stored in a mobility management network element.

[0051] It should be understood that the embodiments of the present application do not limit the naming of the tracking area, and the English abbreviation corresponding to the tracking area. The tracking area described in the present application can be replaced by TA, and can also be replaced by other names, such as the first area, without limitation. The method provided by the embodiments of the present application is described below with the tracking area as TA. In addition, the network slice not supported by the TA described in the present application can be understood as the S-NSSAI of the network slice not supported / available by the TA, or the S-NSSAI not supported / available by the TA, which corresponds to the network slice not supported / available by the TA.

[0052] For example, Table Two shows the correspondence between the TA and the S-NSSAI of the network slice supported by the TA. As shown in Table Two, it is assumed that three types of network slices are deployed in the network, and the S-NSSAI of the three types of network slices is S-NSSAI-1, S-NSSAI-2 and S-NSSAI-3 respectively. Among them, the TA supporting S-NSSAI-1 includes TA1, TA2 and TA4, the TA supporting S-NSSAI-1 includes TA2, TA3 and TA4, and the TA supporting S-NSSAI-3 includes TA1, TA3 and TA4.

[0053] Table Two

[0054] S-NSSAI of a network slice TA supporting the network slice S-NSSAI-1 TA1, TA2, TA4 S-NSSAI-2 TA2, TA3, TA4 S-NSSAI-3 TA1, TA3, TA4

[0055] However, in actual deployment scenarios, there can be a correspondence between the network slice and the frequency (frequency). The frequency corresponding to the network slice can be the frequency point of accessing the network slice. In the present application, the frequency point can be referred to as an access frequency point, that is, the terminal can access the network slice through a dedicated frequency band (or the frequency point corresponding to the network slice). However, the terminal does not perceive the deployment of the network slice, and the terminal blindly selects a cell for camping. This can cause the frequency corresponding to the cell selected by the terminal to not support the network slice that the terminal wants to access, and cannot meet the service requirements of the terminal.

[0056] Currently, in 3GPP standards, in order to ensure that the cell selected by the terminal supports the network slice that the terminal wants to access, the following method is proposed: the mobility management network element judges that the requested NSSAI contains the S-NSSAI of the network slice that the current TA does not support, or understands that the mobility management network element judges that the requested NSSAI contains the S-NSSAI of the network slice that the current TA is unavailable, then rejects the terminal to access the network slice, and puts the S-NSSAI of the network slice into the NSSAI of the network slice that rejects the terminal to access, generates the rejected NSSAI and the rejection reason value: the current TA does not support / the current TA is unavailable. The mobility management network element obtains the target NSSAI according to the rejected NSSAI (rejected NSSAI), at this time the target NSSAI obtained can contain part or all of the S-NSSAI in the NSSAI of the network slice that rejects the terminal to access, and part or all of the S-NSSAI in the NSSAI of the network slice that allows the terminal to access (allowed NSSAI). The mobility management network element obtains the radio access technology / frequency selection priority (RAT / frequency selection priority, RFSP) index corresponding to the target NSSAI according to the target NSSAI, and sends the target NSSAI and the RFSP index to the access network device, triggers the access network device to determine the target TA (which can support any network slice corresponding to the target NSSAI), and further triggers the terminal to access the network slice corresponding to the target NSSAI through the cell (which can be called the target cell) where the target TA is located through the radio resource control (radio resource control, RRC) redirection process.

[0057] For example, assuming that network slice 1 and network slice 2 correspond to frequencies F1 and F2 respectively, TA1 supports network slice 1, TA2 supports network slice 1 and network slice 2, the terminal accesses the cell of TA1 through F1 by the cell selection mechanism, at this time, the requested NSSAI sent by the terminal corresponds to network slice 1 and network slice 2, but TA1 does not support network slice 2, only supports network slice 1, then the mobility management network element rejects the terminal to access network slice 2, at this time, the allowed NSSAI includes the S-NSSAI of network slice 1, and the rejected NSSAI includes the S-NSSAI of network slice 2. In order to realize that the terminal selects the cell of TA2 to access network slice 1 and network slice 2, the mobility management network element obtains the target NSSAI (including the rejected NSSAI (that is, the S-NSSAI of network slice 2) and the allowed NSSAI (that is, the S-NSSAI of network slice 1)), further obtains the RFSP index corresponding to the target NSSAI, sends the target NSSAI and the RFSP index to the access network device, and the access network device judges whether the frequency of the surrounding cell meets the condition according to the RFSP index, if yes, the access network device releases the RRC process, and redirects the terminal to the cell of TA2 to access network slice 1 and network slice 2 through the cell of TA2, so as to meet the service demand of the terminal and improve the service experience of the terminal.

[0058] However, the existing 3GPP standard does not consider the scenario that the requested NSSAI contains S-NSSAI that is not supported by the current TA and needs to perform the NSSAA process, and does not give a solution to the following problems:

[0059] Problem 1: In the registration process, the allowed NSSAI determined by the mobility management network element contains S-NSSAI that does not need to perform the NSSAA process, which can be understood as that the S-NSSAI contained in the allowed NSSAI at this time is a temporary value, after the NSSAA process ends, the mobility management network element can update the allowed NSSAI, such as adding the S-NSSAI for which the NSSAA process is successfully performed to the allowed NSSAI, and the change of the updated allowed NSSAI further affects the determination of the target NSSAI, so it is not accurate to determine the target NSSAI according to the allowed NSSAI determined before the NSSAA process is performed.

[0060] Assuming that the requested NSSAI includes S-NSSAI-1, S-NSSAI-2 and S-NSSAI-3, and the three S-NSSAIs are included in the NSSAI to which the UE is subscribed, the TA in which the RAN currently accessed by the UE is TA3, if TA3 supports S-NSSAI-2 and S-NSSAI-3, the rejected NSSAI includes S-NSSAI-1, if the S-NSSAI-3 supported by TA3 does not need to perform NSSAA, and the S-NSSAI-2 supported by TA3 needs to perform NSSAA, the determined allowed NSSAI includes {S-NSSAI-3}, the pending NSSAI includes {S-NSSAI-2}, and the rejected NSSAI includes {S-NSSAI-1}. According to the existing method, before the NSSAA procedure, the target NSSAI is determined according to the allowed NSSAI including {S-NSSAI-3} and the rejected NSSAI including {S-NSSAI-1}. Since TA1 and TA4 simultaneously support S-NSSAI-1 and S-NSSAI-3, the target NSSAI is determined to include {S-NSSAI-1, S-NSSAI-3}, and according to Table 2, the terminal can access S-NSSAI-1 and S-NSSAI-3 through TA1 or TA4. If the network side determines that the radio resource information corresponding to the target NSSAI is supported by TA1, the terminal accesses S-NSSAI-1 and S-NSSAI-3 through TA1, and the terminal still cannot access S-NSSAI-2 because TA1 does not support S-NSSAI-2.

[0061] In contrast, if the NSSAA procedure ends successfully, and the UE is allowed to access the network slice corresponding to S-NSSAI-2, the current allowed NSSAI includes {S-NSSAI-2, S-NSSAI-3}, and the rejected NSSAI includes {S-NSSAI-1}. If the method of the embodiments of the present application described later is used, at this time, the target NSSAI is determined according to the allowed NSSAI {S-NSSAI-2, S-NSSAI-3} and the rejected NSSAI {S-NSSAI-1}, and since TA4 supports S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, the target NSSAI is determined to include {S-NSSAI-1, S-NSSAI-2, S-NSSAI-3}, and the terminal can access S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 through TA4 at the same time. At this time, the terminal can access three network slices through TA4 at the same time, and the requirements of the terminal can be met.

[0062] It can be seen that the target NSSAI determined by the network side before and after the NSSAA procedure is different, and if the network side does not consider the result of the NSSAA procedure, the target NSSAI determined before the NSSAA procedure is inaccurate and cannot meet the access requirements of the user well.

[0063] Problem 2: In the scenario of deregistration procedure due to NSSAA procedure failure, if the accurate target NSSAI and RFSP index are not determined, the terminal may still select the wrong TA when it registers again, and cannot successfully access the network slice.

[0064] Assuming that the requested NSSAI includes S-NSSAI-1, S-NSSAI-2 and S-NSSAI-3, and the three S-NSSAIs are included in the NSSAI to which the UE subscribes, the TA in which the RAN currently accessed by the UE is TA3, as shown in Table 2, TA3 supports S-NSSAI-2 and S-NSSAI-3, then the rejected NSSAI includes S-NSSAI-1, if both S-NSSAI-2 and S-NSSAI-3 supported by TA3 need to perform NSSAA, the determined allowed NSSAI is empty, and the allowed NSSAI being empty in the present application can be represented as allowed NSSAI {empty}, according to the prior art method, before the NSSAA procedure, the target NSSAI is determined according to the allowed NSSAI {empty} and the rejected NSSAI including {S-NSSAI-1}. Since there is no S-NSSAI in the allowed NSSAI, the target NSSAI includes {S-NSSAI-1}. If the network side determines that the radio resource information corresponding to the target NSSAI is supported by TA1, then the terminal accesses S-NSSAI-1 through TA1, but the terminal still cannot access S-NSSAI-2 and S-NSSAI-3 because TA1 does not support S-NSSAI-2 and S-NSSAI-3.

[0065] If the NSSAA procedures of S-NSSAI-2 and S-NSSAI-3 both fail after the NSSAA procedure, the network slices allowed to be accessed by the UE do not change and are still the empty allowed NSSAI, and the network needs to initiate a deregistration procedure for the terminal. Since the terminal can only obtain the radio resource information supported by TA1, the terminal still does not know which TA supports S-NSSAI-2 and S-NSSAI-3, and therefore when the terminal is registered again, it can still select a wrong TA, resulting in the inability to access S-NSSAI-2 and S-NSSAI-3.

[0066] It can be seen that the target NSSAI determined by the network side before the NSSAA procedure is inaccurate, because if the deregistration procedure is initiated for the terminal after the NSSAA procedure, the terminal can only access the network slices included in the target NSSAI, and cannot access the network slices for which the NSSAA procedure fails.

[0067] To solve the above technical problems, the embodiment of the present application provides a method: a mobility management network element initiates an authentication and authorization process for a network slice to be authenticated and authorized in a network slice requested by a terminal, and determines identification information of a network slice allowed to be accessed by the terminal according to a result of the authentication and authorization process, acquires identification information of a target network slice and wireless resource information corresponding to the target network slice according to the identification information of the network slice allowed to be accessed by the terminal and first information (such as identification information of the network slice requested by the terminal or identification information of the network slice rejected to be accessed by the terminal), and sends the identification information of the target network slice and the wireless resource information corresponding to the target network slice to an access network device, so that the access network device triggers the terminal to successfully access a new network slice supported by a new TA according to the identification information of the target network slice and the wireless resource information corresponding to the target network slice, that is, determines the allowed NSSAI according to the result of the reference NSSAA process, guarantees the accuracy of the determined target NSSAI, and further guarantees that the terminal successfully accesses the network slice corresponding to the target NSSAI through the new TA. Specifically, the implementation process of the method can be referred to the description of the following Figure 5 - Figure 11

[0068] It should be understood that in the embodiment of the present application, the identification information of the network slice rejected to be accessed by the terminal included in the first information can be the rejected NSSAI shown in Table 1, that is, the rejected NSSAI rejected because the current TA does not support.

[0069] Optionally, the first information can be stored on the mobility management network element, so that the mobility management network element acquires the identification information of the network slice rejected to be accessed by the terminal determined before the authentication and authorization process according to the first information stored locally, and further determines the identification information of the target network slice according to the identification information of the network slice rejected to be accessed by the terminal, to solve the problem that the rejected NSSAI has been sent to the terminal in the registration acceptance message, but the mobility management network element cannot acquire the rejected NSSAI after the NSSAA process, and further cannot acquire the target NSSAI according to the rejected NSSAI, because the mobility management network element does not save the rejected NSSAI.

[0070] The method for selecting a tracking area provided by the embodiment of the present application is described below in combination with the drawings of the specification:

[0071] It should be understood that the network architecture and business scenarios described in the embodiment of the present application are for more clearly explaining the technical solutions of the embodiment of the present application, and do not constitute a limitation on the technical solutions provided by the embodiment of the present application. It can be known by those skilled in the art that the technical solutions provided by the embodiment of the present application are also applicable to similar technical problems as the network architecture evolves and new business scenarios appear.

[0072] ​The following takes Figure 2 as an example to describe the method for selecting a tracking area provided by the embodiments of the present application.

[0073] As shown in Figure 2 , a communication system 20 is provided by the embodiments of the present application. The communication system 20 includes a mobility management network element, an access network device, a terminal, and one or more network slices. Optionally, the communication system 20 further includes a network slice selection function network element, a data management network element, a policy control network element, an authentication and authorization network element, and the like.

[0074] The access network device can cover one or more TAs, one TA can include one or more cells, one cell can correspond to one access frequency point, one or more network slices can be deployed in one TA, and the terminal can access the network slices supported by the TA through the access frequency point corresponding to a cell in the TA. For example, if the coverage area of the same access network device includes TA1 and TA2. TA1 includes cell 1, TA1 supports network slice 1, and the frequency point of cell 1 is F1. The terminal can access network slice 1 through F1. TA2 includes cell 2, the access frequency point of cell 2 is F2, TA2 supports network slice 1 and network slice 2, and the terminal can access network slice 1 and network slice 2 through F2. It can be understood that in this scenario, the terminal does not need to replace the access network device, and the terminal only needs to access the network slice from another TA supported by the access network device. For another example, the coverage area of access network device 1 includes TA1, and the coverage area of access network device 2 includes TA2. TA1 includes cell 1, TA1 supports network slice 1, and the frequency point of cell 1 is F1. The terminal can camp on cell 1 under TA1 through F1 and access network slice 1. TA2 includes cell 2, the access frequency point of cell 2 is F2, TA2 supports network slice 2, and the terminal can camp on cell 2 under TA2 through F2 and access network slice 2. It can be understood that in this scenario, the terminal needs to replace the access network device to access different network slices. It should be noted that the present application does not limit whether the terminal needs to replace the access network device to access the target network slice corresponding to the target NSSAI.

[0075] The following introduces the network elements in the system shown in Figure 2

[0076] ​The mobility management network element is mainly used for mobility management in a mobile network, such as user location update, user registration network, user handover, etc. In a 5G communication system, the mobility management network element can be an access and mobility management function (AMF) network element, Namf is a service-based interface provided by the AMF network element, and the AMF network element can communicate with other network functions through Namf. In future communications, such as 6th generation (6G) communications, the mobility management network element can still be an AMF network element, or have other names, which are not limited in the embodiments of the present application.

[0077] The terminal can be a device for realizing a wireless communication function, such as a terminal or a chip used in a terminal, etc., which can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on the water surface (such as ships, etc.); and can also be deployed in the air (such as airplanes, balloons, and satellites, etc.). The terminal can be a user equipment (UE) in a 5G network or a future evolved public land mobile network (PLMN), an access terminal, a terminal unit, a terminal station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a wireless communication device, a terminal agent, or a terminal device, etc. The access terminal can be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device, or other processing devices connected to a wireless modem, a vehicle-mounted device, or a wearable device, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical treatment, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The terminal can be mobile or fixed.

[0078] An access network device (or referred to as a radio access network (RAN) device) is a device that provides a terminal with a wireless communication function. The access network device includes, for example, but is not limited to, a gnodeB (gNB) in 5G, an evolved node B (eNB), a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (for example, a home evolved nodeB, or a home node B (HNB)), a baseBand unit (BBU), a transmitting and receiving point (TRP), a transmitting point (TP), a mobile switching center, and the like.

[0079] A network slice selection function network element is configured to select a network slice for a terminal, and the like. In a 5G communication system, the network slice selection function network element can be a network slice selection function (NSSF) network element. The Nnssf is a service-based interface provided by the NSSF network element, and the NSSF network element can communicate with other network functions through the Nnssf. In future communications, such as 6G communications, the network slice selection function network element can still be the NSSF network element, or have other names, which are not limited in the embodiments of the present application.

[0080] A data management network element can be configured to store user data, such as user subscription data, authentication or authorization data, and the like. Specifically, the network storage network element can be a unified data management network element (UDM) or a network repository function (NRF) or a unified data repository (UDR), and the like.

[0081] A policy control network element can be configured to provide a mobility management network element and a session management function network element with a policy, such as a quality of service (QoS) policy, a slice selection policy, an RFSP index, and the like.

[0082] The authentication and authorization network element can be used for authentication, authorization and charging of network slices and the like. Specifically, the authentication and authorization network element can be an authentication, authorization and charging (AAA) network element and the like.

[0083] It should be noted that, Figure 2 is only an exemplary architecture diagram, in addition to the functional units shown in Figure 2 , the system can also include other functional network elements, such as an operation and management (O&M) network element and the like, and the embodiments of the present application do not limit this. In addition, Figure 2 The names of the various devices in Figure 4 are not limited, in addition to the names shown in , each device can also be named as other names, such as replaced with the name of a network element having the same or similar function, which is not limited.

[0084] Figure 2 The system shown in may be a 3rd generation partnership project (3GPP) communication system, such as a 4th generation (4G) communication system, a long term evolution (LTE) system, and can also be a 5th generation (5G) communication system or a new radio (NR) system, a NR-vehicle-to-everything (V2X) system, any one of an Internet of Things system, and can also be applicable to other next-generation communication systems and the like, which is not limited.

[0085] Figure 2 Taking the communication system shown in Figure 3a or the 5G communication system shown in Figure 3b as an example, as shown in Figure 3a or Figure 3bAs shown, a 5G communication system can include a UE, a data network (DN), and an operator network part. The operator network can include one or more of the following network elements: an authentication server function (AUSF), a network slice-specific authentication and authorization function (NSSAAF), a network slice admission control function (NSACF), an NSSF, a service communication proxy (SCP), a network exposure function (NEF), a policy control function (PCF), a unified data management (UDM), a network repository function (NRF), an application function (AF), an access and mobility management function (AMF), a session management function (SMF), a radio access network (RAN), and a user plane function (UPF).

[0086] Among them, the operator can deploy different network functions inside the network slice according to the network slice template, such as Figure 3a Or Figure 3b SMF, UPF, PCF network elements in the middle to meet the network performance and functional requirements specified in the network slice template. When a terminal requests to access a certain network slice, the network functions supporting the network slice provide services for the terminal.

[0087] Among them, Figure 3a is a schematic diagram of a 5G communication system based on a service-oriented interface; Figure 3a As shown, the control plane network elements such as AMF, SMF, NSSF, etc. can interact with each other using a service-oriented interface. For example, the service-oriented interface provided by the AMF to the outside can be Namf; the service-oriented interface provided by the SMF to the outside can be Nsmf; the service-oriented interface provided by the PCF to the outside can be Npcf; and the service-oriented interface provided by the NSSF to the outside can be Nnssf.

[0088] in, Figure 3b This is a schematic diagram of a 5G communication system based on a point-to-point interface. Figure 3b and Figure 3a The main difference is: Figure 3b The interfaces between various network elements are point-to-point interfaces, not service-oriented interfaces. For example... Figure 3b As shown, Figure 3b The N1 interface serves as the reference point between the terminal and the AMF; the N2 interface serves as the reference point between the RAN device and the AMF, used for sending non-access stratum (NAS) messages and next generation application protocol (NGAP) messages; the N3 interface serves as the reference point between the RAN device and the UPF, used for transmitting user plane data; the N4 interface serves as the reference point between the SMF and the UPF, used for transmitting information such as tunnel identification information for N3 connections, data buffer indication information, and downlink data notification messages; the N9 interface serves as the reference point between UPFs, and so on, which will not be described in detail here.

[0089] Optionally, the mobility management network element, access network device, or network slicing selection function network element in the embodiments of this application may also be referred to as a communication device. It may be a general-purpose device or a dedicated device. The embodiments of this application do not specifically limit it in this way.

[0090] Optionally, the functions of the mobility management network element, access network device, or network slice selection function network element in the embodiments of this application can be implemented by one device, multiple devices, or one or more functional modules within a single device. This application does not specifically limit these functions. It is understood that the aforementioned functions can be network elements in hardware devices, software functions running on dedicated hardware, a combination of hardware and software, or virtualization functions instantiated on a platform (e.g., a cloud platform).

[0091] For example, the related functions of the mobility management network element and access network device in the embodiments of this application can be achieved through... Figure 4 This is achieved through the communication device 400. Figure 4 The diagram shown is a structural schematic of a communication device 400 provided in an embodiment of this application. The communication device 400 includes one or more processors 401, a communication line 402, and at least one communication interface. Figure 4 (This is merely an example illustration, using a communication interface 404 and a processor 401 as examples. Optionally, a memory 403 may also be included.)

[0092] The processor 401 can be a general purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of programs of the present application.

[0093] The communication line 402 can include a path for connecting different components.

[0094] The communication interface 404 can be used for communication with other devices or communication networks, such as Ethernet, RAN, wireless local area networks (WLAN), etc. For example, the communication interface 404 can be a transceiver, a transceiver circuit, or the like. Alternatively, the communication interface 404 can also be a transceiver circuit located in the processor 401 to realize the signal input and output of the processor.

[0095] The memory 403 can be a device with a storage function. For example, it can be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited to this. The memory can exist independently and be connected to the processor through the communication line 402. The memory can also be integrated with the processor.

[0096] The memory 403 stores computer execution instructions for implementing the scheme of this application, and its execution is controlled by the processor 401. The processor 401 executes the computer execution instructions stored in the memory 403 to implement the method for selecting a tracking region provided in the embodiments of this application. Alternatively, in the embodiments of this application, the processor 401 may execute the processing-related functions in the method for selecting a tracking region provided in the following embodiments of this application, and the communication interface 404 is responsible for communicating with other devices or communication networks. The embodiments of this application do not specifically limit this.

[0097] Optionally, the computer execution instructions in the embodiments of this application may also be referred to as application code, and the embodiments of this application do not specifically limit this.

[0098] In a specific implementation, as one example, processor 401 may include one or more CPUs, for example... Figure 4 CPU0 and CPU1 in the example. In a specific implementation, as one embodiment, the communication device 400 may include multiple processors, such as... Figure 4 The processors 401 and 408 are included. Each of these processors can be a single-core processor or a multi-core processor. The processors here can include, but are not limited to, at least one of the following: a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a microcontroller unit (MCU), or an artificial intelligence processor, etc., and various computing devices that run software. Each computing device may include one or more cores for executing software instructions to perform calculations or processing.

[0099] In a specific implementation, as one embodiment, the communication device 400 may further include an output device 405 and an input device 406. The output device 405 communicates with the processor 401 and can display information in various ways. For example, the output device 405 may be a liquid crystal display (LCD), a light-emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector, etc. The input device 406 communicates with the processor 401 and can receive user input in various ways. For example, the input device 406 may be a mouse, keyboard, touchscreen device, or sensing device, etc.

[0100] The communication apparatus 400 described above can also be referred to as a communication device, which can be a general-purpose device or a special-purpose device. For example, the communication apparatus 400 can be a desktop computer, a laptop computer, a network server, a personal digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal, an embedded device, a terminal described above, a network device described above, or a device having a similar structure to the devices described above. Embodiments of the present application are not limited to the type of the communication apparatus 400. In addition, the constituent structures shown in the drawings described above do not constitute a limitation on the communication apparatus 400. The communication apparatus 400 can include more or fewer components than those shown in the drawings, or some components can be combined, or different components can be arranged. Figure 4 The communication apparatus 400 described above can also be referred to as a communication device, which can be a general-purpose device or a special-purpose device. For example, the communication apparatus 400 can be a desktop computer, a laptop computer, a network server, a personal digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal, an embedded device, a terminal described above, a network device described above, or a device having a similar structure to the devices described above. Embodiments of the present application are not limited to the type of the communication apparatus 400. In addition, the constituent structures shown in the drawings described above do not constitute a limitation on the communication apparatus 400. The communication apparatus 400 can include more or fewer components than those shown in the drawings, or some components can be combined, or different components can be arranged. Figure 4 The communication apparatus 400 described above can also be referred to as a communication device, which can be a general-purpose device or a special-purpose device. For example, the communication apparatus 400 can be a desktop computer, a laptop computer, a network server, a personal digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal, an embedded device, a terminal described above, a network device described above, or a device having a similar structure to the devices described above. Embodiments of the present application are not limited to the type of the communication apparatus 400. In addition, the constituent structures shown in the drawings described above do not constitute a limitation on the communication apparatus 400. The communication apparatus 400 can include more or fewer components than those shown in the drawings, or some components can be combined, or different components can be arranged. Figure 4 The communication apparatus 400 described above can also be referred to as a communication device, which can be a general-purpose device or a special-purpose device. For example, the communication apparatus 400 can be a desktop computer, a laptop computer, a network server, a personal digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal, an embedded device, a terminal described above, a network device described above, or a device having a similar structure to the devices described above. Embodiments of the present application are not limited to the type of the communication apparatus 400. In addition, the constituent structures shown in the drawings described above do not constitute a limitation on the communication apparatus 400. The communication apparatus 400 can include more or fewer components than those shown in the drawings, or some components can be combined, or different components can be arranged.

[0101] In embodiments of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices.

[0102] The method for selecting a tracking area provided by embodiments of the present application will be described below in conjunction with the communication system shown in Figure 2 The method for selecting a tracking area provided by embodiments of the present application will be described below in conjunction with the communication system shown in Figure 4 The method for selecting a tracking area provided by embodiments of the present application will be described below in conjunction with the communication system shown in The method for selecting a tracking area provided by embodiments of the present application will be described below in conjunction with the communication system shown in

[0103] The method for selecting a tracking area provided by embodiments of the present application will be described below in conjunction with the communication system shown in Figure 5 The method for selecting a tracking area provided by embodiments of the present application will be described below in conjunction with the communication system shown in The method for selecting a tracking area provided by embodiments of the present application will be described below in conjunction with the communication system shown in

[0104] S500, a terminal sends a registration request message to a mobility management network element through an access network device accessed by the terminal. Correspondingly, the mobility management network element receives the registration request message.

[0105] The terminal can be any terminal that initiates a registration procedure in Figure 2 The terminal can be terminal 1 or terminal 2 in Figure 2 The access network device can be an access network device currently providing access service for the terminal, through which the terminal can send the registration request message to the mobility management network element. The mobility management network element can be a mobility management network element in Figure 2The mobility management network element manages the access network device and establishes a non-access stratum (NAS) connection with the terminal.

[0106] The registration request message can include identification information of a network slice requested by the terminal and other information such as identification information of the terminal. The network slice requested by the terminal can be a network slice requested to be accessed by the terminal, and can be a network slice requested to be accessed by the terminal through the TA in which the access network device is located. The network slice requested by the terminal can include one network slice or multiple network slices, and is not limited. It should be noted that in the embodiments of the present application, the TA in which the access network device currently accessed by the terminal is located can be referred to as the current TA, which is uniformly described here, and will not be described below.

[0107] In the embodiments of the present application, the identification information of the network slice can be used to identify the network slice. The identification information of one network slice can be the S-NSSAI of the network slice, the identification information of the network slice requested by the terminal can be the requested NSSSAI of the terminal, the identification information of the network slice to be authenticated and authorized can be the pending NSSAI, the identification information of the network slice subscribed by the terminal can be the subscribed NSSAI of the terminal, and the identification information of the network slice allowed to be accessed by the terminal can be the allowed NSSAI of the terminal. The description of these NSSAIs can refer to the description in Table 1 above, and will not be described here.

[0108] S501, the mobility management network element obtains the identification information of the network slice to be authenticated and authorized from the identification information of the network slice requested by the terminal.

[0109] Taking the identification information of the network slice as an example of S-NSSAI, S501 can be understood as the mobility management network element obtaining the pending NSSAI from the requested NSSAI.

[0110] For example, after receiving the registration request message, the mobility management network element can determine whether to allow the terminal to access the network slice requested by the terminal according to the network slice to which the terminal subscribes for each network slice requested by the terminal. If the mobility management network element determines that the network slice requested by the terminal is allowed by subscription, but the network slice requested by the terminal is not supported in the current TA or is not available in the current TA, the mobility management network element determines not to allow the terminal to access the network slice requested by the terminal, that is, the terminal is rejected to access the network slice requested by the terminal, and the rejection reason value can include that the current TA does not support (or the current TA is not available). This type of network slice belongs to the network slice that the terminal is rejected to access. Assuming that the identification information of the network slice is S-NSSAI, the identification information of this type of network slice whose rejection reason is that the current TA does not support belongs to rejected NSSAI and is contained in rejected NSSAI. It should be understood that the rejected NSSAI described in the embodiments of the present application refers to the S-NSSAI of the network slice that the terminal is rejected to access due to the rejection reason that the current TA does not support.

[0111] If the mobility management network element determines that the network slice requested by the terminal is allowed by subscription, and the network slice requested by the terminal is supported in the current TA or is available in the current TA, the mobility management network element further determines whether the network slice needs to perform an authentication and authorization (network slice specific authentication and authorization, NSSAA) process. The determination result can cause the following two cases:

[0112] 1) If the network slice does not need to perform authentication and authorization, this type of network slice belongs to the network slice that the terminal is allowed to access. Assuming that the identification information of the network slice is S-NSSAI, the identification information of this type of network slice can be directly contained in allowed NSSAI. It should be understood that the allowed NSSAI determined before the authentication and authorization process in the embodiments of the present application can be referred to as original allowed NSSAI, and the following will not be repeated.

[0113] 2) If the network slice needs to perform authentication and authorization, the network slice belongs to the candidate / pending network slice, which is the network slice to be authenticated and authorized. At this time, the mobility management network element can initiate the authentication and authorization process for the network slice to be authenticated and authorized after the registration process. If the authentication and authorization of a certain network slice is successful, the terminal is allowed to access the network slice, and the identification information of the network slice is added to the allowed NSSAI, that is, the allowed NSSAI is updated. If the authentication and authorization of a certain network slice fails, the terminal is not allowed (or refused) to access the network slice, wherein the refusal reason value is: authentication and authorization failure.

[0114] In the embodiments of the present application, the mobility management network element can pre-store a TA list, the TA list including one or more TAs, and the mobility management network element also stores the correspondence between the TAs and the identification information of the network slices supported by the TAs. If the identification information of the network slice requested by the terminal is not included in the identification information of the network slices supported by the TA, it is determined that the TA does not support the network slice. For example, assuming that the mobility management network element stores {TA1, S-NSSAI-1}, {TA2, S-NSSAI-1, S-NSSAI-2}, the terminal requests S-NSSAI-1 and S-NSSAI-2 through the RAN, and the TA of the RAN is TA1, according to the correspondence stored by the mobility management network element, it can be determined that TA1 does not support S-NSSAI-2, that is, the current TA does not support S-NSSAI-2. For another example, assuming that the mobility management network element stores {TA1, S-NSSAI-1}, {TA2, S-NSSAI-1, S-NSSAI-2}, {TA3, S-NSSAI-2, S-NSSAI-3}, the terminal requests S-NSSAI-1, S-NSSAI-2 and S-NSSAI-3 through the RAN, and the TA of the RAN is TA3, according to the correspondence stored by the mobility management network element, it can be determined that TA3 does not support S-NSSAI-1, that is, the current TA does not support S-NSSAI-1.

[0115] In the embodiments of the present application, the related information of the network slice to which the terminal subscribes can be pre-stored in the subscription data of the terminal. The subscription data of the terminal can include the identification information of the network slice to which the terminal subscribes, and the indication information of whether each network slice needs to perform the NSSAA of the network slice. The correspondence between the identification information of the network slice to which the terminal subscribes and the indication information of whether the network slice needs to perform the authentication and authorization of the network slice can be included in the subscription data of the terminal in the form of a list. The subscription data of the terminal can be pre-stored in a data storage network element, such as a UDM. The mobility management network element can obtain the subscription data of the terminal from the data storage network element.

[0116] In the embodiments of the present application, if the network slice requested by the terminal is included in the network slice subscribed by the terminal, the network slice requested by the terminal can be considered as allowed by subscription. If the identification information of the network slice requested by the terminal is included in the subscription data of the terminal, and the subscription data of the terminal indicates that the authentication and authorization of the network slice need to be performed, the identification information of the network slice is determined as the identification information of the network slice to be authenticated and authorized.

[0117] For example, taking the identification information of the network slice as S-NSSAI, Table 3 below shows the correspondence between S-NSSAI and the indication information of whether the network slice needs to perform the authentication and authorization of the network slice. It should be understood that Table 3 is only an exemplary table, and other S-NSSAI can be included in addition to those shown in Table 3, without limitation. As shown in Table 3, the NSSAI subscribed by the terminal includes S-NSSAI-1, S-NSSAI-2 and S-NSSAI-3, wherein S-NSSAI-1 and S-NSSAI-2 need to perform the authentication and authorization of the network slice, and S-NSSAI-3 does not need to perform the authentication and authorization of the network slice. Assuming that the identification information of the network slice requested by the terminal includes S-NSSAI-2 and S-NSSAI-3, the mobility management network element can find Table 3 by taking S-NSSAI-2 as an index to determine that S-NSSAI-2 needs to perform the authentication and authorization of the network slice, and find Table 3 by taking S-NSSAI-3 as an index to determine that S-NSSAI-3 does not need to perform the authentication and authorization of the network slice. At this time, the pending NSSAI in S-NSSAI-2 and S-NSSAI-3 requested by the terminal includes S-NSSAI-2, and the allowed NSSAI includes S-NSSAI-3.

[0118] Table 3

[0119]

[0120] Further optionally, after performing S501, the mobility management network element sends a registration accept message to the terminal, the registration accept message corresponds to the registration request message in S500, and the registration accept message can include the identification information of the network slice allowed to be accessed by the terminal (such as the original allowed NSSAI), the identification information of the network slice rejected to be accessed by the terminal (such as the rejected NSSASI), and the identification information of the network slice to be authenticated and authorized (such as the pending NSSAI), so that the terminal knows which network slices among the network slices requested by the terminal are allowed to be accessed, which network slices are rejected, and which network slices are to be authenticated and authorized, thereby completing the registration process initiated by the terminal in S500.

[0121] In the embodiments of the present application, the original allowed NSSAI can refer to the NSSAI in the requested NSSAI of the terminal that belongs to the subscribed NSSAI of the terminal and does not need to be authenticated and authorized, and is the allowed NSSAI stored in the mobility management network element after the registration process is determined to be completed. The name of the original allowed NSSAI is not limited, and it can also be named as the old allowed NSSAI or the first allowed NSSAI.

[0122] Further optionally, the mobility management network element stores the identification information of the network slices allowed to be accessed by the terminal (i.e., stores the original allowed NSSI) in the context of the terminal, so as to update the stored identification information of the network slices allowed to be accessed by the terminal according to the result of the authentication and authorization after the to-be-authenticated-and-authorized process is completed.

[0123] Further optionally, the mobility management network element can also store the first information, which can include the identification information of the network slices requested by the terminal or the identification information of the network slices refused to be accessed by the terminal, such as storing the first information in the context of the terminal, so as to determine the identification information of the target network slice according to the stored first information and the updated identification information of the network slices allowed to be accessed by the terminal.

[0124] In the embodiments of the present application, the mobility management network element can store the first information on the mobility management network element in the case that the mobility management network element determines that the identification information of the network slices requested by the terminal includes the identification information of the network slices refused to be accessed by the terminal.

[0125] Further, in the case that the mobility management network element determines that the identification information of the network slices requested by the terminal includes the identification information of the network slices refused to be accessed by the terminal, the mobility management network element can also generate the first indication information, which can be used to indicate one or more of the following: selecting a new TA for the terminal, wherein the new TA supports the target network slice; or redirecting the terminal to a tracking area or a frequency band (redirection to dedicated frequency band(s)) that supports the target network slice; or obtaining the second information for the terminal after the authentication and authorization process, so that the mobility management network element determines the identification information of the target network slice according to the first information and the updated identification information of the network slices allowed to be accessed by the terminal after the authentication and authorization process in response to the first indication information.

[0126] Further, after the mobility management network element generates the first indication information, the first indication information is stored in the context of the terminal.

[0127] In the present application, the first indication information is not limited to the name, and can also be referred to as a flag or other names.

[0128] S502, the mobility management network element initiates an authentication and authorization process for the network slice to be authenticated and authorized.

[0129] Taking the identification information of the network slice as an S-NSSAI, S502 can be understood as the mobility management network element initiating an authentication and authorization process for the S-NSSAI in the pending NSSAI.

[0130] For example, the mobility management network element initiating an authentication and authorization process for the network slice to be authenticated and authorized can include the mobility management network element indicating the identification information of the network slice to be authenticated and authorized to the authentication and authorization network element, triggering the authentication and authorization network element to authenticate and authorize the network slice to be authenticated and authorized, and after the authentication and authorization is completed, the authentication and authorization network element feeds back the authentication and authorization result to the mobility management network element. The authentication and authorization network element can be an AAA network element, and the process of the authentication and authorization network element authenticating and authorizing the network slice can refer to the prior art and will not be described here.

[0131] S503, the mobility management network element determines the identification information of the network slice allowed to be accessed by the terminal according to the result of the authentication and authorization process of the network slice.

[0132] Taking the identification information of the network slice as an S-NSSAI, S503 can be understood as the mobility management network element determining the allowed NSSAI according to the result of the authentication and authorization process of the pending S-NSSAI. It should be understood that the identification information of the network slice allowed to be accessed by the terminal determined in S503 can refer to a new (new) allowed NSSAI, which is the allowed NSSAI determined according to the result of the authentication and authorization process. The name of the new allowed NSSAI is not limited, and it can also be named as a second allowed NSSAI.

[0133] In the present application, the result of the authentication and authorization process of the network slice can include successful authentication and authorization of the network slice, or failed authentication and authorization of the network slice. The mobility management network element determining the identification information of the network slice allowed to be accessed by the terminal according to the result of the authentication and authorization process of the network slice can include the following two examples:

[0134] In an example, if the authentication and authorization of the network slice succeeds, the mobility management network element updates the identity information of the network slice allowed to be accessed by the terminal. Specifically, the mobility management network element adds the identity information of the network slice whose authentication and authorization succeeds to the identity information of the network slice allowed to be accessed by the terminal stored in the context of the terminal. Taking the identity information of the network slice as S-NSSAI for example, in the case that the authentication and authorization of the S-NSSAI included in the pending NSSAI succeeds, the original allowed NSSAI is updated, i.e., the S-NSSAI whose authentication and authorization succeeds and which is included in the pending NSSAI is added to the original allowed NSSAI. Specifically, the scenario is shown in the following Figure 6 or Figure 7 .

[0135] In another example, if the authentication and authorization of the network slice fails, only the identity information of the network slice which does not need to perform authentication and authorization among the identity information of the network slice requested by the terminal is determined as the identity information of the network slice allowed to be accessed by the terminal. Taking the identity information of the network slice as S-NSSAI for example, i.e., in the case that the authentication and authorization of all the S-NSSAIs included in the pending NSSAI fails, the original allowed NSSAI remains unchanged. Specifically, the scenario is shown in the following Figure 8 - Figure 11 .

[0136] For example, it is assumed that the pending NSSAI includes S-NSSAI-2 and the original allowed NSSAI includes S-NSSAI-3. If the authentication and authorization of S-NSSAI-2 succeeds, the original allowed NSSAI is updated to a new allowed NSSAI, and the new allowed NSSAI includes S-NSSAI-2 and S-NSSAI-3. If the authentication and authorization of S-NSSAI-2 fails, the original allowed NSSAI remains unchanged and still includes S-NSSAI-3.

[0137] S504, the mobility management network element acquires second information according to the identity information of the network slice allowed to be accessed by the terminal and the first information determined in S503; the first information includes the identity information of the network slice rejected to be accessed by the terminal or the identity information of the network slice requested by the terminal.

[0138] In the embodiment of the present application, the network slice rejected to be accessed by the terminal can be a network slice which is not supported by the TA where the access network device is located among the network slices requested by the terminal.

[0139] In an embodiment of the present application, the second information can include identification information of the target network slice and radio resource information corresponding to the target network slice. The radio resource information corresponding to the target network slice can be used to indicate an access frequency point of the target network slice. For example, the radio resource information corresponding to the target network slice can be a radio access technology (RAT) / frequency selection priority (RFSP) index corresponding to the target network slice, which can correspond to an access frequency point that can support the target network slice. The access frequency point corresponding to the RFSP index can be pre-stored on an access network device or a policy control network element, such as a RAN or a PCF.

[0140] For example, taking the identification information of the network slice as S-NSSAI and the radio resource information corresponding to the target network slice as the RFSP index, the identification information of the network slice that rejects the terminal access can be rejected NSSAI, and the identification information of the target network slice can be target NSSAI. S504 can be replaced with the mobility management network element obtaining the target NSSAI and the RFSP index according to the allowed NSSAI and the requested NSSAI determined in S503, or obtaining the target NSSAI and the RFSP index according to the allowed NSSAI and the rejected NSSAI.

[0141] In an embodiment of the present application, the first information can be stored on the mobility management network element, such as the context of the terminal stored on the mobility management network element in S501. After the execution of S503 is completed, the mobility management network element can obtain the first information from the local context, and obtain the second information according to the first information and the identification information of the network slice that allows the terminal to access. Optionally, after obtaining the second information, the mobility management network element can delete the stored first information.

[0142] Optionally, after the execution of S503 is completed, the mobility management network element can obtain the second information according to the identification information of the network slice that allows the terminal to access and the first information determined in S503 in response to the first indication information. That is, the first indication information can be used as a trigger condition / indication signal to trigger / instruct the mobility management network element to execute S504. As described in S501, the first indication information can be pre-stored in the context of the terminal stored locally, and the mobility management network element can obtain the first indication information from the local context and execute S504 in response to the first indication information. Optionally, after obtaining the second information, that is, after executing S504, the mobility management network element can delete the stored first indication information.

[0143] For example, the mobility management network element acquires the second information according to the identity information of the network slice allowed to be accessed by the terminal and the first information can include the following two possible designs:

[0144] In one possible design, the mobility management network element can determine the second information according to the identity information of the network slice allowed to be accessed by the terminal and the first information by itself. Specifically, the process can refer to the description in Figure 6 , Figure 8 or Figure 10 .

[0145] In another possible design, the second information can be determined by other network elements according to the identity information of the network slice allowed to be accessed by the terminal and the first information, and the determined second information is fed back to the mobility management network element. For example, the mobility management network element can send the identity information of the network slice allowed to be accessed by the terminal and the first information to the network slice selection function network element, and receive the second information from the network slice selection function network element. Specifically, the process can refer to the description in Figure 7 , Figure 9 or Figure 11 .

[0146] S505, the mobility management network element sends the second information to the access network device, and correspondingly, the access network device receives the second information.

[0147] In one possible design, if the authentication and authorization procedure of the network slice to be authenticated and authorized succeeds, the mobility management network element initiates a UE configuration update procedure, and sends a first message including a UE configuration update command and the first information to the access network device, that is, the second information is sent to the access network device through the UE configuration update procedure in the scenario where the authentication and authorization succeeds, so as to reduce the signaling overhead. Specifically, the process can refer to the description in Figure 6 or 7.

[0148] In another possible design, if the authentication and authorization procedures of the network slices to be authenticated and authorized all fail, and the identity information of the network slice allowed to be accessed by the terminal is not empty, for example, the new allowed NSSAI is not empty, and the new allowed NSSAI contains at least one S-NSSAI, the mobility management network element sends a UE context update request carrying the second information to the access network device. Specifically, the process can refer to the description in Figure 8 or Figure 9 .

[0149] In another possible design, if the authentication and authorization processes for the network slices to be authenticated and authorized all fail, and the identifier information of the network slices allowed for terminal access is empty (e.g., the new allowed NSSAI is empty, and the new original allowed NSSAI does not contain any S-NSSAI), the mobility management network element sends a UE context release request carrying the second information to the access network device. Specifically, this process can be referred to as follows: Figure 10 or Figure 11 As described in [the text].

[0150] Furthermore, the access network device can send a radio resource control (RRC) release message to the terminal. The RRC release message can carry the access frequency point indicated by the radio resource information corresponding to the target network slice, so that the terminal can select a new TA according to the access frequency point and initiate a registration request message carrying the identification information of the target network slice in the cell where the new TA is located (which can be referred to as the target cell in this application) to successfully access the target network slice.

[0151] based on Figure 5 The method, in a scenario where the mobility management element determines that the TA of the current access network device does not support the S-NSSAI in the requested NSSAI, and the mobility management element determines that the requested NSSAI includes an S-NSSAI that requires NSAA (e.g., a pending NSSAI), determines the allowed NSSAI based on the NSAA result of the S-NSSAI included in the pending NSSAI. Then, based on the allowed NSSAI and the first information (requested NSSAI or rejected NSSAI (i.e., the rejection reason is that the current TA does not support the S-NSSAI)), it determines the target NSSAI and the RFSP index corresponding to the target NSSAI. The target NSSAI and the RFSP index corresponding to the target NSSAI are sent to the access network device, triggering the access network device to instruct the terminal to select a new TA. This new TA supports all network slices corresponding to the target NSSAI, ensuring that the UE can successfully access the network slice through the new TA in scenarios where the requested NSSAI includes both S-NSSAIs that the current TA does not support and S-NSSAIs that require NSAA.

[0152] The following is combined Figure 3a or Figure 3bThe communication system shown assumes that the identifier information of the network slice requested by the terminal is "requested NSSAI", the identifier information of the network slice that the terminal is denied access to is "rejected NSSAI", the identifier information of the network slice pending authentication and authorization is "pending NSSAI", the identifier information of the network slice that the terminal is allowed to access before the authentication and authorization process for the pending NSSAI is "original allowed NSSAI", and the identifier information of the network slice that the terminal is allowed to access based on the authentication and authorization of the pending NSSAI is "new allowed NSSAI". The terminal is UE, the access network device is RAN, and the policy control network element is PCF. The method for selecting the tracking area provided in this application embodiment is specifically described. It should be understood that the message names between various network elements or the names of the parameters in the messages in the following embodiments are just examples, and other names may be used in specific implementations. This application embodiment does not specifically limit this.

[0153] like Figure 6 As shown in the figure, a method for selecting a tracking region provided in an embodiment of this application includes the following steps:

[0154] S601. The UE sends a registration request message to the AMF through the RAN it is currently connected to. Correspondingly, the AMF receives the registration request message through the RAN the UE is currently connected to.

[0155] This registration request message can be used to request network registration for the terminal. The message can carry the terminal's requested NSSAI, as well as other information, such as the terminal's identification information. This identification information can be used to identify the terminal; it can be the terminal's globally unique temporary UE identity (5G-GUTI) or its subscription permanent identifier (SUPI).

[0156] S602, AMF determines the S-NSSAIs that the TA where the RAN is located in the requested NSSAI does not support, and determines the S-NSSAIs in the requested NSSAIs that need to execute NSSAA.

[0157] Specifically, the AMF stores S-NSSAIs supported by each TA, and can determine, according to the locally stored S-NSSAIs supported by the TA where the RAN is located, S-NSSAIs in the requested NSSAI that are included in the subscription data of the terminal but not supported by the TA where the RAN is located, and take the S-NSSAIs not supported by the TA where the RAN is located as the rejected NSSAI. In the embodiments of the present application, the S-NSSAIs not supported by the TA where the RAN is located can also be understood as S-NSSAIs that the terminal is not allowed to access through the TA where the RAN is located or as S-NSSAIs that are not available in the TA where the RAN is located, and the rejection reason is that the current TA does not support.

[0158] In addition, the AMF can also obtain the subscription data of the UE, which can include S-NSSAIs subscribed by the UE and indication information of whether the S-NSSAIs need to perform NSSAA, and the AMF can determine, according to the subscription data of the UE, whether the S-NSSAIs included in the requested NSSAI need to perform NSSAA, place S-NSSAIs included in the subscription data and needing to perform NSSAA in the requested NSSAI in the pending NSSAI, determine S-NSSAIs included in the subscription data and not needing to perform NSSAA in the requested NSSAI as S-NSSAIs that the UE is allowed to access, and place these S-NSSAIs that the UE is allowed to access in the allowed NSSAI. In order to distinguish the description, in the embodiments of the present application, the allowed NSSAI determined by the AMF before the NSSAA procedure is referred to as the original allowed NSSAI.

[0159] For example, the subscription data of the UE can be pre-stored in the UDM, and the AMF can call the service interface Nudm_SDM_Get of the UDM to obtain the subscription data of the UE, the UDM sends the subscription data of the UE to the AMF through the service interface Nudm_SDM_Get response, and then determines the pending NSSAI and the original allowed NSSAI according to the obtained subscription data of the UE.

[0160] It should be understood that, in the embodiments of the present application, the S-NSSAIs included in the original allowed NSSAI are different (or have no intersection) from the S-NSSAIs included in the rejected NSSAI, and the S-NSSAIs included in the original allowed NSSAI are different (or have no intersection) from the S-NSSAIs included in the pending NSSAI.

[0161] S603, the AMF saves the first information in the context of the UE.

[0162] The first information can include rejected NSSAI or requested NSSAI.

[0163] Optionally, the AMF also saves first indication information in the context of the UE. The first indication information, as described in S501, can be used to indicate one or more of the following: indicating that a new TA is selected for the terminal, the new TA supports target NSSAI, or indicating that the UE needs to be redirected to access the network slice on another TA or other frequency band. Alternatively, it indicates that after the NSSAA procedure is completed, the AMF needs to obtain the target NSSAI and the corresponding RFSP index.

[0164] It should be understood that saving the first indication information is an optional step, which can be performed or not, without limitation.

[0165] S604, the AMF sends a registration accept message to the UE through the RAN. Correspondingly, the UE receives the registration accept message from the AMF through the RAN.

[0166] The registration accept message can carry rejected NSSAI, pending NSSAI, and original allowed NSSAI.

[0167] Specifically, the AMF can send an N2 message carrying the registration accept message to the RAN, the RAN receives the N2 message, obtains the registration accept message from the N2 message, and sends the registration accept message to the UE.

[0168] S605, the AMF initiates an NSSAA procedure for each S-NSSAI included in the pending NSSAI, and obtains the result of the NSSAA procedure for each S-NSSAI.

[0169] Specifically, the execution process of the NSSAA procedure can refer to the prior art, which will not be described here.

[0170] S606, if the result of the NSSAA procedure of the S-NSSAI included in the pending NSSAI is that the authentication and authorization is successful, the AMF puts the S-NSSAI of which the NSSAA procedure in the pending NSSAI is successful and the original allowed NSSAI determined by the AMF in S602 into the new allowed NSSAI, which means that the allowed NSSAI determined after the NSSAA procedure includes not only the allowed NSSAI determined in S603, but also the pending NSSAI of which the authentication and authorization is successful.

[0171] For example, assume that the requested NSSAI includes S-NSSAI-1, S-NSSAI-2 and S-NSSAI-3, and the three S-NSSAIs are included in the NSSAI to which the UE subscribes. If the TA in which the RAN currently accessed by the UE is TA1, if TA1 supports S-NSSAI-1, the rejected NSSAI includes S-NSSAI-2 and S-NSSAI-3, and it can be known according to Table 3 that TA1 supports S-NSSAI-1 which needs to perform the NSSAA, so the pending NSSAI includes S-NSSAI-1, and the original allowed NSSAI is empty. The AMF initiates the NSSAA procedure for S-NSSAI-1, and if the authentication and authorization of S-NSSAI-1 is successful, the original allowed NSSAI is updated, S-NSSAI-1 is put into the original allowed NSSAI to obtain the new allowed NSSAI, and the new allowed NSSAI determined at this time includes S-NSSAI-1.

[0172] For example, assume that the requested NSSAI includes S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and the three S-NSSAIs are included in the NSSAI to which the UE is subscribed. If the TA in which the RAN currently accessed by the UE is TA3, if TA3 supports S-NSSAI-2 and S-NSSAI-3, the rejected NSSAI includes S-NSSAI-1, and according to Table 3, it is known that: TA3 supports S-NSSAI-2, which needs to perform NSSAA, and the pending NSSAI includes S-NSSAI-2, and TA3 supports S-NSSAI-3, which does not need to perform NSSAA, and the original allowed NSSAI is {S-NSSAI-3}. The AMF initiates the NSSAA procedure for S-NSSAI-2, and if the authentication and authorization of S-NSSAI-2 are successful, the original allowed NSSAI is updated, S-NSSAI-2 is placed in the original allowed NSSAI to obtain a new allowed NSSAI, and at this time, the determined new allowed NSSAI is {S-NSSAI-2, S-NSSAI-3}, which is different from the allowed NSSAI determined in the above problem 1.

[0173] S607, the AMF determines the target NSSAI according to the first information and the new allowed NSSAI determined in S606.

[0174] Optionally, if the AMF stores the first information and the first indication information in S603, the AMF can obtain the first information from the context of the UE in response to the first indication information after the NSSAA procedure for all S-NSSAIs included in the pending NSSAI is completed, determine the target NSSAI according to the first information and the new allowed NSSAI, and then perform signaling interaction with the PCF to obtain the RFSP index corresponding to the target NSSAI from the PCF.

[0175] In an embodiment of the present application, the target NSSAI can include part or all of the S-NSSAI in the rejected NSSAI; or include part or all of the S-NSSAI in the rejected NSSAI and part or all of the S-NSSAI in the new allowed NSSAI. For the target NSSAI, there is a TA in the network, which can support all the S-NSSAI included in the target NSSAI, which can be referred to as a common TA. There is a cell (which can be referred to as a target cell in the present application) in the common TA, and the frequency point of the cell corresponds to the network slice (i.e., the target network slice) indicated by all the S-NSSAI included in the target NSSAI, and the frequency point of the cell in the present application can be referred to as a common access frequency point, and the terminal can access the target network slice through the frequency point of the cell in the common TA. That is, in the embodiment of the present application, the determined target NSSAI satisfies the following condition: all the network slices corresponding to the target NSSAI can be supported in a certain common TA, so that when the target NSSAI is determined, the network side device can determine the RFSP index corresponding to the target network slice according to the target NSSAI, the RFSP index corresponds to / indicates a certain access frequency point (i.e., a common access frequency point) in the common TA corresponding to the target network slice, and the access frequency point can be used for the terminal to access the target network slice.

[0176] In an embodiment of the present application, the process of determining the target NSSAI by the AMF according to the first information and the new allowed NSSAI is as follows. It should be understood that the following is an example of the AMF determining the target NSSAI, and the process of determining the target NSSAI by other network elements (such as the NSSF) according to the first information and the new allowed NSSAI can be referred to the following.

[0177] In an example, the first information includes the requested NSSAI, and the AMF can determine the target NSSAI according to the first information and the new allowed NSSAI in any of the following two implementation manners:

[0178] In the first manner, the AMF determines the NSSAI (i.e., the rejected NSSAI) not supported by the current TA from the requested NSSAI according to the supported NSSAI of the current TA, and determines which S-NSSAI in the rejected NSSAI and the new allowed NSSAI is included in the target NSSAI according to the supported S-NSSAI of each TA deployed by the network. Specifically, the following is performed:

[0179] (1) The target NSSAI includes part of the S-NSSAIs in the rejected NSSAI or all of the S-NSSAIs in the rejected NSSAI, and does not include the S-NSSAIs included in the new allowed NSSAI.

[0180] For example, if there is a TA in the TA list, the TA supports part of the S-NSSAIs in the rejected NSSAI, but the TA does not support any of the S-NSSAIs included in the allowed NSSAI, the target NSSAI includes part of the S-NSSAIs in the rejected NSSAI. Or, if the TA supports all of the S-NSSAIs in the rejected NSSAI, but the TA does not support any of the S-NSSAIs included in the allowed NSSAI, the target NSSAI includes all of the S-NSSAIs in the rejected NSSAI.

[0181] For another example, if the rejected NSSAI includes K S-NSSAIs, K is an integer greater than or equal to 1, the K S-NSSAIs are supported by different TAs respectively, that is, there is no common TA that supports the K S-NSSAIs included in the rejected NSSAI, and the network slices indicated by the S-NSSAIs included in the rejected NSSAI are deployed in different TAs, the AMF can select one S-NSSAI from the rejected NSSAI as the target NSSAI according to a local policy.

[0182] The local policy can include at least one of the following: selecting an S-NSSAI with high priority, or selecting an S-NSSAI with minimum load. As an implementation manner, the AMF can obtain the priority information of the S-NSSAI from the subscription data of the terminal or other network elements.

[0183] The above process can be understood as follows: the TA supporting the S-NSSAIs included in the rejected NSSAI is different from the TA supporting the S-NSSAIs included in the allowed NSSAI, and it cannot be guaranteed that the terminal accesses the rejected NSSAI and the allowed NSSAI through one TA at the same time. However, there is a TA, and the terminal can access part of the S-NSSAIs in the rejected NSSAI or all of the S-NSSAIs in the rejected NSSAI through a cell of the TA at the same time. The terminal resides in the cell of the TA, and the terminal can request to access part of the S-NSSAIs in the rejected NSSAI or all of the S-NSSAIs in the rejected NSSAI through a certain access frequency point at the same time.

[0184] It should be understood that the embodiments of the present application do not limit the deployment location of the TA (which can be referred to as a target TA or a new TA) that supports all S-NSSAIs included in the target NSSAI, and the deployment location of the TA can or can not overlap with the deployment location of the TA (i.e., the current TA) where the access network device currently accessed by the terminal is located. When the deployment location of the target TA overlaps with the deployment location of the current TA, and the common access frequency point corresponding to the target NSSAI corresponds to a certain target cell in the overlapping area, it means that the terminal can access the target network slice corresponding to the target NSSAI from the target cell in the current overlapping area.

[0185] (2) The target NSSAI includes part or all of the S-NSSAIs in the rejected NSSAI, and includes part or all of the S-NSSAIs in the new allowed NSSAI.

[0186] For example, the AMF determines, according to the TA list stored locally and the network slices supported by each TA, that there is a TA in the network, the TA can support part or all of the S-NSSAIs in the rejected NSSAI, and the TA can also support part or all of the S-NSSAIs in the allowed NSSAI. Therefore, the target NSSAI can include part or all of the S-NSSAIs in the rejected NSSAI and part or all of the S-NSSAIs in the allowed NSSAI.

[0187] The above process can be understood as that there is a TA in the network, and the terminal can access part or all of the S-NSSAIs in the rejected NSSAI and part or all of the S-NSSAIs in the allowed NSSAI through a cell of the TA. If the terminal camps on the cell of the TA, the terminal can request to access part or all of the S-NSSAIs in the rejected NSSAI and part or all of the S-NSSAIs in the allowed NSSAI through a certain frequency point.

[0188] It should be understood that the "includes" described in the embodiments of the present application can be understood as "contains" or "carries", and these words have the same meaning and can be used interchangeably without limitation.

[0189] (3) Determine which S-NSSAIs are included in the target NSSAI based on the session association of the terminal.

[0190] For example, if the terminal currently has a session (e.g., a protocol data unit (PDU) session of the terminal) established, and the S-NSSAI associated with the session is included in the allowed NSSAI, in order to ensure service continuity of the session of the terminal, the AMF can determine whether there is a TA that supports the S-NSSAI associated with the session of the terminal in the allowed NSSAI, if there is, determine whether the TA also supports part or all of the S-NSSAI of the rejected NSSAI, if the TA also supports part or all of the S-NSSAI of the rejected NSSAI, it means that the terminal can access part or all of the S-NSSAI of the rejected NSSAI and the S-NSSAI associated with the session of the terminal in the allowed NSSAI simultaneously through a cell in the TA. Then the target NSSAI can include part or all of the S-NSSAI of the rejected NSSAI and the S-NSSAI associated with the session of the terminal in the allowed NSSAI. Optionally, the terminal can also access other S-NSSAI supported by the TA in the allowed NSSAI through a cell in the TA. Correspondingly, the target NSSAI can also include other S-NSSAI supported by the TA in the allowed NSSAI.

[0191] In the second way, the first information includes the requested NSSAI, and the AMF determines the requested NSSAI as the target NSSAI.

[0192] For example, the AMF determines, according to the locally stored TA list and the network slices supported by each TA, that there is a TA that can support all S-NSSAIs included in the requested NSSAI, at this time, the AMF can directly determine the requested NSSAI as the target NSSAI.

[0193] In another example, the first information includes the rejected NSSAI, and the AMF determines the target NSSAI according to the first information and the new allowed NSSAI can include: the AMF determines the target NSSAI according to the rejected NSSAI and the new allowed NSSAI. Specifically, this process can refer to the description in the first way above, and will not be repeated here.

[0194] It should be understood that, in addition to the above manner, the mobility management network element can also determine which S-NSSAIs are included in the target NSSAI according to other manners, which are not limited in the present application.

[0195] For example, it is assumed that the new allowed NSSAI includes {S-NSSAI-1, S-NSSAI-2}, the rejected NSSAI includes S-NSSAI-3, as shown in Table 2, TA1, TA2 and TA3 support S-NSSAI-3, TA1 and TA2 support S-NSSAI-1, TA2 and TA3 support S-NSSAI-2, there is TA2 that supports S-NSSAI-3, S-NSSAI-1 and S-NSSAI-2, and the access frequency point 1 of the cell in TA2 can completely cover / support the UE to access the network slices corresponding to S-NSSAI-1, S-NSSAI-2 and S-NSSAI-3, then the target NSSAI is determined as {S-NSSAI-1, S-NSSAI-2, S-NSSAI-3}.

[0196] S608, the AMF sends the target NSSAI to the PCF. Correspondingly, the PCF receives the target NSSAI from the AMF.

[0197] For example, the AMF can call the service operation of the PCF: service interface Npcf_AMPolicyControl_Update request, and send the target NSSAI to the PCF in the Npcf_AMPolicyControl_Update request.

[0198] Optionally, the AMF also sends the identification information and other information of the UE to the PCF, which are not limited.

[0199] S609, the PCF determines the RFSP index corresponding to the target NSSAI according to the target NSSAI, and sends the RFSP index corresponding to the target NSSAI to the AMF. Correspondingly, the AMF receives the RFSP index corresponding to the target NSSAI from the PCF.

[0200] Specifically, the PCF locally configures the correspondence between the S-NSSAI and the RFSP index, and the PCF determines the RFSP index corresponding to the target NSSAI according to the target NSSAI and the correspondence between the S-NSSAI and the RFSP index.

[0201] Exemplarily, the PCF invokes its own service operation: service interface Npcf AMPolicyControl Update response, carries the RFSP index corresponding to the target NSSAI in the Npcf AMPolicyControl Update response, and sends it to the AMF.

[0202] Since there is an S-NSSAI in the pending NSSAI that has successfully executed the NSSAA, the allowed NSSAI is updated, and therefore the AMF needs to send the new allowed NSSAI to the UE through the UE configuration update procedure. In the UE configuration update procedure, the target NSSAI and the RFSP index corresponding to the target NSSAI can be sent to the RAN to reduce the signaling overhead. Specifically, the process is as described in S610 and S611.

[0203] Optionally, after the AMF determines the target NSSAI and the RFSP index corresponding to the target NSSAI, the AMF can delete the first information stored in the context of the UE. In addition, if the AMF also stores the first indication information in S603, after determining the target NSSAI and the RFSP index corresponding to the target NSSAI, the AMF can also delete the first indication information.

[0204] S610, the AMF sends a first message to the RAN, and the first message carries a UE configuration update command and second information {target NSSAI, RFSP index corresponding to the target NSSAI}. Correspondingly, the RAN receives the first message from the AMF.

[0205] The first message can be an N2 message. The UE configuration update command can carry the new allowed NSSAI, and the UE configuration update command can be used to indicate the update of the related configuration of the UE, such as the update of the allowed NSSAI of the UE.

[0206] S611, the RAN sends the UE configuration update command to the UE. Correspondingly, the UE receives the UE configuration update command.

[0207] S612, the RAN determines information of an access frequency point corresponding to the target NSSAI according to the target NSSAI and the RFSP index corresponding to the target NSSAI, and sends the information of the access frequency point corresponding to the target NSSAI to the UE. Correspondingly, the UE receives the information of the access frequency point corresponding to the target NSSAI.

[0208] In an implementation form, the information of the access frequency point corresponding to the target NSSAI can be used to indicate the access frequency point corresponding to the target NSSAI, and can be used for the UE to select a target cell that can support access to all network slices corresponding to the target NSSAI. Specifically, the information of the access frequency point corresponding to the target NSSAI can be an index of the access frequency point corresponding to the target NSSAI, and the UE can access all network slices corresponding to the target NSSAI through the access frequency point. For example, the access frequency point corresponding to the target NSSAI is F1, and the information of the access frequency point corresponding to the target NSSAI includes F1.

[0209] Specifically, the RAN locally configures a correspondence between a subscriber profile ID for RAT / frequency selection priority (SPID) and band priority list information, or a correspondence between an RFSP index and band priority list information. The correspondence can be as shown in Table Four. The RAN can determine band priority list information corresponding to the RFSP index corresponding to the target NSSAI according to the RFSP index carried in the first message and the correspondence, and select the access frequency point corresponding to the target NSSAI from the determined band priority list information.

[0210] Table Four

[0211] RFSP index Frequency band priority list information RFSP index-1 Access frequency point 1 RFSP index-2 Access frequency point 2 RFSP index-2 Access frequency point 3

[0212] It should be understood that the band priority list information in the present application can also be referred to as band information, or a band list, or band priority information, or a band priority list, frequency information, or a frequency list, or frequency priority information, or a frequency priority list, frequency point information, or a frequency point list, or frequency point priority information, or a frequency point priority list. It should be noted that the SPID on the wireless side and the RFSP index on the core network side are the same concept, and in order to unify, both the core network side and the wireless side are referred to as RFSP index in the present application.

[0213] It should be understood that the access frequency point described in the embodiments of the present application can also be understood as a frequency band or an access frequency band, which is not limited.

[0214] For example, the RAN can send the information of the access frequency point corresponding to the target NSSAI to the UE through an access network release (AN release) process. For example, the RAN can send a radio resource control (RRC) release message to the UE, the RRC release message can be used to instruct the UE to release the connection with the current cell, select a new cell, and the RRC release message can carry the information of the access frequency point corresponding to the target NSSAI.

[0215] S613, the UE selects a target cell according to the information of the access frequency point corresponding to the target NSSAI, and initiates a registration update process to the target cell. For example, according to S612, after the UE receives the information of the access frequency point corresponding to the target NSSAI from the RAN, the UE selects a cell supporting the access frequency point and camps on it, and sends a registration request message carrying a requested NSSAI to the AMF through the cell. At this time, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0216] It should be understood that in addition to including the requested NSSAI, the registration request message can also include other information, such as the identification information of the UE.

[0217] S614, the AMF triggers other processes of other network elements to complete other processes of the registration process according to the received registration request message, so as to realize that the UE accesses the network slice corresponding to the target NSSAI at the current location.

[0218] Specifically, the process can refer to the prior art, which will not be described here.

[0219] Based on Figure 6In the method, in a scenario where the AMF determines that the S-NSSAI in the requested NSSAI is not supported by the TA where the current RAN is located, and the AMF determines that the S-NSSAI that needs to perform the NSSAA (such as the pending NSSAI) is included in the requested NSSAI, after the NSSAA procedure is performed on all S-NSSAIs included in the pending NSSAI, and the NSSAA of the S-NSSAI is successfully performed, the AMF determines the target NSSAI according to the new allowed NSSAI and the first information (the requested NSSAI or the rejected NSSAI), and obtains the RFSP index corresponding to the target NSSAI from the PCF, and sends the target NSSAI and the RFSP index corresponding to the target NSSAI to the RAN, to trigger the RAN to instruct the UE to select a new TA, the new TA being capable of supporting all network slices corresponding to the target NSSAI, so as to ensure that the UE can successfully access the network slice in a scenario where the requested NSSAI includes the S-NSSAI not supported by the current TA and the S-NSSAI that needs to perform the NSSAA.

[0220] The above Figure 6 In the method, the target NSSAI and the RSFP index corresponding to the target NSSAI are determined by the AMF itself and obtained from the PCF. Alternatively, the target NSSAI and the RSFP index corresponding to the target NSSAI can also be determined by other network elements and sent to the AMF. Specifically, the method can refer to the description in the following Figure 7 . Figure 7 The execution processes of S701-S706 in the method are the same as those of S601-S606 in the method Figure 6 , the execution processes of S709-S715 are the same as those of S608-S614 in the method Figure 6 , and S707-S708 can be used as an alternative method of S607.

[0221] Figure 7 Another method for selecting a tracking area provided by an embodiment of the present application can include the following steps. Figure 7 As shown in the method, the method can include the following steps.

[0222] S701, the UE sends a registration request message to the AMF through the currently accessed RAN. Correspondingly, the AMF receives the registration request message through the RAN currently accessed by the UE.

[0223] Specifically, the related description of the registration request message, the execution process of S701 is the same as S601, and is not described herein.

[0224] S702, the AMF determines the S-NSSAI that the TA where the RAN is located in the requested NSSAI does not support, and determines the S-NSSAI that needs to perform the NSSAA in the requested NSSAI.

[0225] Specifically, S702 is the same as S602, and is not described herein.

[0226] S703, the AMF saves the first information in the context of the UE.

[0227] Optionally, the AMF also saves the first indication information in the context of the UE.

[0228] Specifically, the related description of the first indication information and the execution process of S703 are the same as S603, and are not described herein.

[0229] S704, the AMF sends a registration accept message to the UE through the RAN. Correspondingly, the UE receives the registration accept message from the AMF through the RAN.

[0230] Specifically, S704 is the same as S604, and is not described herein.

[0231] S705, the AMF initiates the NSSAA procedure for each S-NSSAI included in the pending NSSAI, and obtains the result of the NSSAA procedure of each S-NSSAI.

[0232] Specifically, the execution process of the NSSAA procedure can refer to the prior art, and is not described herein.

[0233] S706, if the result of the NSSAA procedure of the S-NSSAI included in the pending NSSAI is that the authentication and authorization is successful, the AMF puts the S-NSSAI in the pending NSSAI for which the NSSAA procedure is successful and the original allowed NSSAI determined in S702 into a new allowed NSSAI, which means that the allowed NSSAI determined after the NSSAA procedure includes not only the allowed NSSAI (i.e., the original allowed NSSAI) determined in S703, but also the S-NSSAI for which the authentication and authorization is successful in the pending NSSAI.

[0234] Specifically, S706 is the same as S606, and is not described herein.

[0235] S707. The AMF sends the first information and the new allowed NSSAI determined in S706 to the NSSF. Correspondingly, the NSSF receives the first information and the new allowed NSSAI determined in S706, and determines the target NSSAI according to the first information and the new allowed NSSAI determined in S706.

[0236] Specifically, the AMF can invoke a service operation of the NSSF: the service interface Nnssf_NSSelection_Get sends the first information and the new allowed NSSAI determined in S706 to the NSSF. Optionally, the AMF also sends indication information indicating the NSSF to determine the target NSSAI to the NSSF, so that the NSSF determines the target NSSAI according to the first information and the new allowed NSSAI determined in S706 in response to the indication information.

[0237] It should be understood that if the AMF stores the first information and the first indication information in S703, the AMF can acquire the first information from the context of the UE in response to the first indication information after the NSSAA procedure of all S-NSSAIs included in the pending NSSAI is completed, and send the first information and the new allowed NSSAI determined in S706 to the NSSF.

[0238] The process of the NSSF determining the target NSSAI is the same as that of the AMF determining the target NSSAI, and is not described herein.

[0239] S708. The NSSF sends the target NSSAI to the AMF. Correspondingly, the AMF receives the target NSSAI.

[0240] Specifically, the NSSF invokes a service operation of the NSSF: the service interface Nnssf_NSSelection_Get response returns the target NSSAI to the AMF.

[0241] S709. The AMF sends the target NSSAI to the PCF. Correspondingly, the PCF receives the target NSSAI from the AMF.

[0242] Specifically, S709 is the same as S608, and is not described herein.

[0243] S710, the PCF determines the RFSP index corresponding to the target NSSAI according to the target NSSAI, and sends the RFSP index corresponding to the target NSSAI to the AMF. Correspondingly, the AMF receives the RFSP index corresponding to the target NSSAI from the PCF.

[0244] Specifically, S710 is the same as S609, and will not be described here.

[0245] Optionally, after the AMF obtains the target NSSAI and the RFSP index corresponding to the target NSSAI, the AMF can delete the first information stored in the context of the UE. In addition, if the AMF also stores the first indication information in S703, after obtaining the target NSSAI and the RFSP index corresponding to the target NSSAI, the AMF can also delete the first indication information.

[0246] Since there is an S-NSSAI in the pending NSSAI that has successfully executed NSSAA, the allowed NSSAI is updated, so the AMF needs to send the new allowed NSSAI to the UE through the UE configuration update procedure. In the UE configuration update procedure, the target NSSAI and the RFSP index corresponding to the target NSSAI can be sent to the RAN to reduce signaling overhead. Specifically, the process is described as S711 and S712.

[0247] S711, the AMF sends a first message to the RAN, and the first message carries a UE configuration update command and second information {target NSSAI, RFSP index corresponding to the target NSSAI}. Correspondingly, the RAN receives the first message from the AMF.

[0248] Specifically, S711 is the same as S610, and will not be described here.

[0249] S712, the RAN sends a UE configuration update command to the UE. Correspondingly, the UE receives the UE configuration update command.

[0250] S713, the RAN determines the information of the access frequency point corresponding to the target NSSAI according to the target NSSAI and the RFSP index corresponding to the target NSSAI, and sends the information of the access frequency point corresponding to the target NSSAI to the UE. Correspondingly, the UE receives the information of the access frequency point corresponding to the target NSSAI.

[0251] Specifically, S713 is the same as S612, and details are not repeated.

[0252] S714, the UE selects a target cell according to the information of the access frequency point corresponding to the target NSSAI, and initiates a registration update process to the target cell. For example, after the UE receives the information of the access frequency point corresponding to the target NSSAI from the RAN according to S713, the UE selects a cell supporting the access frequency point and camps on it, and sends a registration request message carrying the requested NSSAI to the AMF through the cell. At this time, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0253] It should be understood that in addition to including the requested NSSAI, the registration request message can also include other information, such as UE identification information.

[0254] S715, the AMF triggers other processes of other network elements to complete other processes of the registration process according to the received registration request message, so as to realize that the UE accesses the network slice corresponding to the target NSSAI at the current location.

[0255] Specifically, the process can refer to the prior art, and details are not repeated.

[0256] Based on Figure 7 As shown in the method, in the scenario where the AMF determines that the TA where the current RAN is located does not support the S-NSSAI in the requested NSSAI, and the AMF determines that the requested NSSAI contains an S-NSSAI (such as pending NSSAI) that needs to perform NSSAA, after the NSSAA process of all S-NSSAIs included in the pending NSSAI is completed, and the NSSAA of the S-NSSAI is successfully performed, the AMF obtains the target NSSAI from the NSSF according to the new allowed NSSAI and the first information (requested NSSAI or rejected NSSAI), obtains the RFSP index corresponding to the target NSSAI from the PCF, and sends the target NSSAI and the RFSP index corresponding to the target NSSAI to the RAN, to trigger the RAN to instruct the UE to select a new TA, which can support all network slices corresponding to the target NSSAI, so as to ensure that the UE can successfully access the network slice in the scenario where the requested NSSAI contains S-NSSAI that the current TA does not support and S-NSSAI that needs to perform NSSAA.

[0257] The aboveFigure 6 Or Figure 7 In the method shown in the above formula, in the scenario that the TA where the current RAN is located does not support the S-NSSAI in the requested NSSAI, and the requested NSSAI contains the S-NSSAI (such as the pending NSSAI) that needs to perform the NSSAA, the method for selecting the tracking area is described by taking the successful execution of the NSSAA of the S-NSSAI included in the pending NSSAI as an example. The following describes the scenario that the NSSAA of all the S-NSSAIs included in the pending NSSAI all fail.

[0258] Figure 8 Another method for selecting a tracking area provided by an embodiment of the present application can include the following steps. Figure 8

[0259] S801, the UE sends a registration request message to the AMF through the currently accessed RAN. Correspondingly, the AMF receives the registration request message through the RAN currently accessed by the UE.

[0260] Specifically, the related description of the registration request message and the execution process of S801 are the same as those of S601, and are not described herein.

[0261] S802, the AMF determines the S-NSSAI in the requested NSSAI that is not supported by the TA where the RAN is located, and determines the S-NSSAI in the requested NSSAI that needs to perform the NSSAA.

[0262] Specifically, S802 is the same as S602, and is not described herein.

[0263] S803, the AMF saves the first information in the context of the UE.

[0264] Optionally, the AMF also saves the first indication information in the context of the UE.

[0265] Specifically, the related description of the first indication information and the execution process of S803 are the same as those of S603, and are not described herein.

[0266] S804, the AMF sends a registration accept message to the UE through the RAN. Correspondingly, the UE receives the registration accept message from the AMF through the RAN.

[0267] Specifically, S804 is the same as S604, and is not described herein.

[0268] ​S805. The AMF initiates the NSSAA procedure for each S-NSSAI included in the pending NSSAI, and obtains the result of the NSSAA procedure for each S-NSSAI.

[0269] Specifically, the execution process of the NSSAA procedure can refer to the prior art, and will not be described herein.

[0270] S806. If the result of the NSSAA procedure for all S-NSSAIs included in the pending NSSAI is authentication and authorization failure, the AMF does not update the original allowed NSSAI determined by the AMF in S802, which means that the allowed NSSAI determined after the NSSAA procedure only includes the allowed NSSAI determined in S803 (i.e., the original allowed NSSAI), and the new allowed NSSAI is the same as the original allowed NSSAI.

[0271] Specifically, S806 is the same as S606, and will not be described herein.

[0272] It should be noted that, Figure 8 In the embodiments shown, the original allowed NSSAI is not empty, that is, the original allowed NSSAI includes at least one S-NSSAI.

[0273] For example, it is assumed that the requested NSSAI includes S-NSSAI-1, S-NSSAI-2 and S-NSSAI-3, and the three S-NSSAIs are included in the NSSAI subscribed by the UE. If the TA where the RAN currently accessed by the UE is TA3, if TA3 supports S-NSSAI-2 and S-NSSAI-3, the rejected NSSAI includes S-NSSAI-1, and according to Table 3, it can be known that: TA3 supports S-NSSAI-2 which needs to perform NSSAA, and S-NSSAI-3 which does not need to perform NSSAA, and the original allowed NSSAI is {S-NSSAI-3}. The AMF initiates the NSSAA procedure for S-NSSAI-2, and if the NSSAA of S-NSSAI-2 fails, the original allowed NSSAI is not updated, and the new allowed NSSAI determined at this time is {S-NSSAI-3}, which is the same as the original allowed NSSAI.

[0274] S807. The AMF determines the target NSSAI according to the first information and the new allowed NSSAI determined in S806.

[0275] Specifically, the description of S807 can refer to S607. It should be understood that, since the NSSAA procedure of the pending NSSAI fails in S806, the new allowed NSSAI is the original allowed NSSAI, i.e., the allowed NSSAI determined before the NSSAA procedure is not updated, and S807 can be understood as determining the target NSSAI according to the first information and the original allowed NSSAI, which will not be repeated.

[0276] It should be understood that, if the AMF stores the first information and the first indication information in S803, the AMF can obtain the first information from the context of the UE in response to the first indication information after the NSSAA procedure of all S-NSSAIs included in the pending NSSAI is completed, and determine the target NSSAI according to the first information and the original allowed NSSAI.

[0277] S808, the AMF sends the target NSSAI to the PCF. Correspondingly, the PCF receives the target NSSAI from the AMF.

[0278] Specifically, S808 is the same as S608, which will not be repeated.

[0279] S809, the PCF determines the RFSP index corresponding to the target NSSAI according to the target NSSAI, and sends the RFSP index corresponding to the target NSSAI to the AMF. Correspondingly, the AMF receives the RFSP index corresponding to the target NSSAI from the PCF.

[0280] Specifically, S809 is the same as S609, which will not be repeated.

[0281] Optionally, after the AMF determines the target NSSAI and obtains the RFSP index corresponding to the target NSSAI, the AMF can delete the first information stored in the context of the UE. In addition, if the AMF also stores the first indication information in S703, after determining the target NSSAI and obtaining the RFSP index corresponding to the target NSSAI, the AMF can also delete the first indication information.

[0282] Since the NSSAA of all S-NSSAI in the pending NSSAI fails, the allowed NSSAI is not updated, and is the original allowed NSSAI. Since the original allowed NSSAI has been sent to the UE in the registration accept message, the AMF does not need to send the new allowed NSSAI to the UE through the UE configuration update process, but initiates the UE context update request to update the access frequency point of the UE. Specifically, the process is as described in S810.

[0283] S810, the AMF sends a UE context update request (UE context modification request) to the RAN, and the UE context update request carries the second information {target NSSAI, RFSP index corresponding to the target NSSAI}. Correspondingly, the RAN receives the UE context update request from the AMF.

[0284] The UE context update request can be used to request to update the context of the UE stored on the RAN, such as to update the access frequency point of the UE in the context of the UE. In addition to carrying the second information, the UE context update request can also carry other information, such as carrying the identification information of the UE, which is not limited.

[0285] S811, the RAN determines the information of the access frequency point corresponding to the target NSSAI according to the target NSSAI and the RFSP index corresponding to the target NSSAI, and sends the information of the access frequency point corresponding to the target NSSAI to the UE. Correspondingly, the UE receives the information of the access frequency point corresponding to the target NSSAI.

[0286] Specifically, S811 is the same as S612, which is not described here.

[0287] S812, the UE selects a target cell according to the information of the access frequency point corresponding to the target NSSAI, and initiates a registration update process to the target cell. For example, according to S811, after the UE receives the information of the access frequency point corresponding to the target NSSAI from the RAN, the UE selects a cell supporting the access frequency point and camps on it, and sends a registration request message carrying a requested NSSAI to the AMF through the cell. At this time, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0288] It should be understood that in addition to including the requested NSSAI, the registration request message can also include other information, such as the identification information of the UE.

[0289] S813 and AMF trigger other network elements to complete other processes of the registration process based on the received registration request message, so that the UE can access the network slice corresponding to the target NSSAI at the current location.

[0290] Specifically, the process can be referred to existing technologies, and will not be elaborated here.

[0291] based on Figure 8 The method described above, in a scenario where the AMF determines that the TA currently serving the RAN does not support the S-NSSAI in the requested NSSAI, and the AMF also determines that the requested NSSAI includes S-NSSAIs that require NSSAA execution (e.g., pending NSSAI), if all NSSAA executions for the pending NSSAI fail, the original allowed NSSAI is not updated. The resulting new allowed NSSAI is identical to the original allowed NSSAI. Then, based on the new allowed NSSAI (which can be understood as the original allowed NSSAI) and the first piece of information (requested NSSAI or rejected NSSAI), the target NSSAI is obtained from the NSSF, and the corresponding RFSP index is obtained from the PCF. The target NSSAI and its corresponding RFSP index are then sent to the RAN, triggering the RAN to instruct the UE to select a new TA / cell for access. This new TA / cell can support all network slices corresponding to the target NSSAI, ensuring that the requested NSSAI is supported. NSSAI includes both S-NSSAI, which is not currently supported by TA, and S-NSSAI that requires NSSAA, enabling UEs to successfully access network slices.

[0292] The above Figure 8 The method describes the process by which the AMF determines the target NSSAI and interacts with the PCF to obtain the RFSP index corresponding to the target NSSAI when all S-NSSAIs included in the pending NSSAI fail NSSAI. Alternatively, other network elements can determine the target NSSAI, interact with the PCF to obtain the RFSP index corresponding to the target NSSAI, and send the target NSSAI and its corresponding RFSP index to the AMF. Specifically, this method can be referred to as follows: Figure 9 As described in [the text].

[0293] Figure 9Another method for selecting a tracking area provided by the embodiments of the present application, as shown in Figure 9 may include the following steps.

[0294] S901, the UE sends a registration request message to the AMF through the currently accessed RAN. Correspondingly, the AMF receives the registration request message through the RAN currently accessed by the UE.

[0295] Specifically, the related description of the registration request message and the execution process of S901 are the same as S601, and are not described here.

[0296] S902, the AMF determines the S-NSSAI that is not supported by the TA where the RAN is located in the requested NSSAI, and determines the S-NSSAI that needs to perform NSSAA in the requested NSSAI.

[0297] Specifically, S902 is the same as S602, and is not described here.

[0298] S903, the AMF saves the first information in the context of the UE.

[0299] Optionally, the AMF also saves the first indication information in the context of the UE.

[0300] Specifically, the related description of the first indication information and the execution process of S903 are the same as S603, and are not described here.

[0301] S904, the AMF sends a registration accept message to the UE through the RAN. Correspondingly, the UE receives the registration accept message from the AMF through the RAN.

[0302] Specifically, S904 is the same as S604, and is not described here.

[0303] S905, the AMF initiates the NSSAA procedure for each S-NSSAI included in the pending NSSAI, and obtains the result of the NSSAA procedure of each S-NSSAI.

[0304] Specifically, the execution process of the NSSAA procedure can refer to the prior art, and is not described here.

[0305] S906, if the result of the NSSAA procedure for all S-NSSAIs included in the pending NSSAI is authentication and authorization failure, the AMF does not update the original allowed NSSAI determined by the AMF in S902, which means that the allowed NSSAI determined after the NSSAA procedure only includes the allowed NSSAI determined in S903 (i.e., the original allowed NSSAI), and the new allowed NSSAI is the same as the original allowed NSSAI.

[0306] Specifically, S906 is the same as S806, and is not described here.

[0307] It should be noted that, Figure 9 In the embodiments shown, the original allowed NSSAI is not empty, that is, the original allowed NSSAI includes at least one S-NSSAI.

[0308] S907, the AMF sends the first information and the new allowed NSSAI to the NSSF. Correspondingly, the NSSF receives the first information and the original allowed NSSAI, and the NSSF determines the target NSSAI according to the first information and the new allowed NSSAI.

[0309] It should be understood that, since the NSSAA procedure of the pending NSSAI in S906 fails, the new allowed NSSAI is the same as the original allowed NSSAI, that is, the allowed NSSAI determined before the NSSAA procedure is not updated, and the new allowed NSSAI in S907 can be understood as the original allowed NSSAI.

[0310] Specifically, the AMF can call the service operation of the NSSF: the service interface Nnssf_NSSelection_Get sends the first information and the original allowed NSSAI to the NSSF. Optionally, the AMF also sends indication information indicating that the NSSF determines the target NSSAI to the NSSF, so that the NSSF determines the target NSSAI according to the first information and the original allowed NSSAI in response to the indication information.

[0311] It should be understood that, if the AMF stores the first information and the first indication information in S903, the AMF can acquire the first information from the context of the UE after the NSSAA procedure of all S-NSSAIs included in the pending NSSAI is completed, and send the first information and the new allowed NSSAI determined in S906 to the NSSF in response to the first indication information.

[0312] The process of determining the target NSSAI by the NSSF is the same as that of the AMF, and is not described herein.

[0313] S908. The NSSF sends the target NSSAI to the AMF. Correspondingly, the AMF receives the target NSSAI.

[0314] Specifically, the NSSF invokes the service operation of the NSSF: the service interface Nnssf_NSSelection_Get response (Nnssf_NSSelection_Get response) returns the target NSSAI to the AMF.

[0315] S909. The AMF sends the target NSSAI to the PCF. Correspondingly, the PCF receives the target NSSAI from the AMF.

[0316] Specifically, S909 is the same as S608, and is not described herein.

[0317] S910. The PCF determines the RFSP index corresponding to the target NSSAI according to the target NSSAI, and sends the RFSP index corresponding to the target NSSAI to the AMF. Correspondingly, the AMF receives the RFSP index corresponding to the target NSSAI from the PCF.

[0318] Specifically, S910 is the same as S609, and is not described herein.

[0319] Optionally, after the AMF obtains the target NSSAI and the RFSP index corresponding to the target NSSAI, the AMF can delete the first information stored in the context of the UE. In addition, if the AMF also stores the first indication information in S903, after obtaining the target NSSAI and the RFSP index corresponding to the target NSSAI, the AMF can also delete the first indication information.

[0320] Since the NSSAA of all S-NSSAIs in the pending NSSAI fails, the allowed NSSAI is not updated, and is the original allowed NSSAI. Since the original allowed NSSAI has been sent to the UE in the registration acceptance message, the AMF does not need to send the new allowed NSSAI to the UE through the UE configuration update process, but initiates a UE context update request to update the access frequency point of the UE. Specifically, the process is described in S911.

[0321] S911, the AMF sends a UE context update request to the RAN, the UE context update request carrying the second information {target NSSAI, RFSP index corresponding to the target NSSAI}. Correspondingly, the RAN receives the UE context update request from the AMF.

[0322] Specifically, S911 is the same as S810, and will not be described herein.

[0323] S912, the RAN determines the information of the access frequency point corresponding to the target NSSAI according to the target NSSAI and the RFSP index corresponding to the target NSSAI, and sends the information of the access frequency point corresponding to the target NSSAI to the UE. Correspondingly, the UE receives the information of the access frequency point corresponding to the target NSSAI.

[0324] Specifically, S912 is the same as S612, and will not be described herein.

[0325] S913, the UE selects a target cell according to the information of the access frequency point corresponding to the target NSSAI, and initiates a registration update process to the target cell. For example, according to S912, after the UE receives the information of the access frequency point corresponding to the target NSSAI from the RAN, the UE selects a cell supporting the access frequency point and camps on the cell, and sends a registration request message carrying a requested NSSAI to the AMF through the cell, at this time, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0326] It should be understood that in addition to the requested NSSAI, the registration request message can also include other information, such as UE identification information.

[0327] S914, the AMF triggers other processes of other network elements to complete other processes of the registration process according to the received registration request message, so as to realize that the UE accesses to the network slice corresponding to the target NSSAI at the current location.

[0328] Specifically, the process can refer to the prior art, and will not be described herein.

[0329] Based on Figure 9In the method, in a scenario where the AMF determines that the TA in which the current RAN is located does not support the S-NSSAI in the requested NSSAI, and the AMF determines that the requested NSSAI contains the S-NSSAI that needs to perform the NSSAA (such as the pending NSSAI), after the NSSAA procedure of all S-NSSAIs included in the pending NSSAI is performed, and the NSSAA of the S-NSSAI fails, the original allowed NSSAI is not updated, the new allowed NSSAI obtained is the same as the original allowed NSSAI, the AMF obtains the target NSSAI from the NSSF according to the new allowed NSSAI (which can be understood as the original allowed NSSAI) and the first information (the requested NSSAI or the rejected NSSAI), obtains the RFSP index corresponding to the target NSSAI from the PCF, and sends the target NSSAI and the RFSP index corresponding to the target NSSAI to the RAN, to trigger the RAN to instruct the UE to select a new TA, the new TA can support all network slices corresponding to the target NSSAI, and ensure that the UE can successfully access the network slice in a scenario where the requested NSSAI contains the S-NSSAI that the current TA does not support and the S-NSSAI that needs to perform the NSSAA.

[0330] The above Figure 8 Or Figure 9 In the method, in a scenario where the current RAN is located in a TA that does not support the S-NSSAI in the requested NSSAI, and the requested NSSAI contains the S-NSSAI that needs to perform the NSSAA (such as the pending NSSAI), the selection of the TA is described by taking the example that the NSSAA of all S-NSSAIs included in the pending NSSAI fails, and the original allowed NSSAI is not empty. The following describes a method for selecting a tracking area when the NSSAA of all S-NSSAIs included in the pending NSSAI fails, and the original allowed NSSAI is empty:

[0331] Figure 10 Another method for selecting a tracking area provided by the embodiments of the present application is provided, in which the AMF itself determines the target NSSAI, for example, Figure 10 The method can include:

[0332] S1001, the UE sends a registration request message to the AMF through the currently accessed RAN. Correspondingly, the AMF receives the registration request message through the RAN where the UE is currently accessed.

[0333] Specifically, the related description of the registration request message and the execution process of S1001 are the same as those of S601, and are not described herein again.

[0334] S1002, the AMF determines the S-NSSAI that is not supported by the TA where the RAN is located in the requested NSSAI, and determines the S-NSSAI that needs to perform the NSSAA in the requested NSSAI. It should be noted that, Figure 10 In the illustrated embodiment, the original allowed NSSAI is empty, i.e., there is no S-NSSAI in the original allowed NSSAI.

[0335] Specifically, the execution process of S1002 is the same as that of S602, and is not described herein again.

[0336] For example, it is assumed that the requested NSSAI includes S-NSSAI-1, S-NSSAI-2 and S-NSSAI-3, and the three S-NSSAIs are included in the NSSAI to which the UE subscribes. If the TA where the RAN the UE is currently accessed is TA1, if TA1 supports S-NSSAI-1, the rejected NSSAI includes S-NSSAI-2 and S-NSSAI-3, and according to Table Three, it can be known that the S-NSSAI-1 supported by TA1 needs to perform the NSSAA, the pending NSSAI includes S-NSSAI-1, and the original allowed NSSAI is empty.

[0337] S1003, the AMF saves the first information in the context of the UE.

[0338] Optionally, the AMF also saves the first indication information in the context of the UE.

[0339] Specifically, the related description of the first indication information and the execution process of S1003 are the same as those of S603, and are not described herein again.

[0340] S1004, the AMF sends a registration accept message to the UE through the RAN. Correspondingly, the UE receives the registration accept message from the AMF through the RAN.

[0341] Specifically, S1004 is the same as S604, and is not described herein again. It should be understood that, Figure 10The original allowed NSSAI included in the registration accept message in the embodiment is empty (or referred to as empty allowed NSSAI), and the registration accept message can carry the original allowed NSSAI or not.

[0342] S1005, the AMF initiates the NSSAA procedure for each S-NSSAI included in the pending NSSAI, and obtains the result of the NSSAA procedure of each S-NSSAI.

[0343] Specifically, the execution process of the NSSAA procedure can refer to the prior art and will not be described herein.

[0344] S1006, if the results of the NSSAA procedures of all S-NSSAIs included in the pending NSSAI are all authentication authorization failures, the AMF does not update the original allowed NSSAI determined by the AMF in S1002, which means that the allowed NSSAI (which can be referred to as new allowed NSSAI) determined after the NSSAA procedure is empty, and there is no identification information of the network slice allowed to access the terminal.

[0345] Specifically, S1006 is the same as S606, and will not be described herein.

[0346] For example, following the example in S1002, the AMF initiates the NSSAA procedure for S-NSSAI-1, and if the NSSAA of S-NSSAI-1 fails, the original allowed NSSAI is not updated, and the new allowed NSSAI determined after the NSSAA procedure is still empty.

[0347] S1007, the AMF determines the target NSSAI according to the first information and the new allowed NSSAI determined in S1006.

[0348] It should be understood that if the AMF stores the first information and the first indication information in S1003, the AMF can obtain the first information from the context of the UE in response to the first indication information after the NSSAA procedures of all S-NSSAIs included in the pending NSSAI are completed, and determine the target NSSAI according to the first information.

[0349] Specifically, S1007 can refer to S607. Since the NSSAA procedure of the pending NSSAI in S1006 fails, the new allowed NSSAI is empty, and S1007 can be understood as determining the target NSSAI according to the first information.

[0350] S1008, the AMF sends the target NSSAI to the PCF. Correspondingly, the PCF receives the target NSSAI from the AMF.

[0351] Specifically, S1008 is the same as S608, and is not described here.

[0352] S1009, the PCF determines the RFSP index corresponding to the target NSSAI according to the target NSSAI, and sends the RFSP index corresponding to the target NSSAI to the AMF. Correspondingly, the AMF receives the RFSP index corresponding to the target NSSAI from the PCF.

[0353] Specifically, S1009 is the same as S609, and is not described here.

[0354] Optionally, after the AMF determines the target NSSAI and obtains the RFSP index corresponding to the target NSSAI, the AMF can delete the first information stored in the context of the UE. In addition, if the AMF also stores the first indication information in S1003, after determining the target NSSAI and obtaining the RFSP index corresponding to the target NSSAI, the AMF can also delete the first indication information.

[0355] Since the NSSAA of all S-NSSAIs in the pending NSSAI fails, the allowed NSSAI is not updated and is empty, this registration fails, and the AMF initiates a deregistration process, releases the context of the UE on the RAN, and indicates the information of the access frequency point corresponding to the target network slice for the UE in the process of releasing the context of the UE, so that the UE accesses the target network slice through a new TA / cell. Specifically, the process is described as S1010 and S1011.

[0356] S1010, the AMF initiates a deregistration process to the UE through the RAN. For example, the AMF sends a deregistration request to the UE through the RAN, triggering the UE to deregister / withdraw this network registration.

[0357] S1011, the AMF sends a UE context release request to the RAN, and the UE context release request carries the second information {target NSSAI, RFSP index corresponding to the target NSSAI}. Correspondingly, the RAN receives the UE context release request from the AMF.

[0358] The UE context release request can be used to request to release the context of the UE stored on the RAN. In addition to carrying the second information, the UE context release request can also carry the identification information of the UE and other information, which are not limited.

[0359] S1012, the RAN determines the information of the access frequency point corresponding to the target NSSAI according to the target NSSAI and the RFSP index corresponding to the target NSSAI, and sends the information of the access frequency point corresponding to the target NSSAI to the UE. Correspondingly, the UE receives the information of the access frequency point corresponding to the target NSSAI.

[0360] Specifically, S1011 is the same as S612, which is not described herein.

[0361] S1013, the UE selects a target cell according to the information of the access frequency point corresponding to the target NSSAI, and initiates a registration update process to the target cell. For example, according to S1012, after the UE receives the information of the access frequency point corresponding to the target NSSAI from the RAN, the UE selects a cell supporting the access frequency point and camps on it, and sends a registration request message carrying a requested NSSAI to the AMF through the cell. At this time, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0362] It should be understood that in addition to including the requested NSSAI, the registration request message can also include other information, such as the identification information of the UE.

[0363] S1014, the AMF triggers other processes of other network elements to complete other processes of the registration process according to the received registration request message, so as to realize the access of the UE to the network slice corresponding to the target NSSAI at the current location.

[0364] Specifically, the process can refer to the prior art, which is not described herein.

[0365] Based on Figure 10In the method, in a scenario where the AMF determines that the S-NSSAI in the requested NSSAI is not supported by the TA where the current RAN is located, and the AMF determines that the S-NSSAI that needs to perform the NSSAA (such as the pending NSSAI) is included in the requested NSSAI, if the NSSAA of all S-NSSAIs included in the pending NSSAI fails, and the allowed NSSAI is empty, the AMF initiates a deregistration process, determines the target NSSAI according to the first information (the requested NSSAI or the rejected NSSAI) and the empty allowed NSSAI, obtains the RFSP index corresponding to the target NSSAI from the PCF, and sends the target NSSAI and the RFSP index corresponding to the target NSSAI to the RAN, so as to trigger the RAN to instruct the UE to select a new TA / cell access, the new TA / cell can support all network slices corresponding to the target NSSAI, and the UE can successfully access the network slice in a scenario where the requested NSSAI includes the S-NSSAI not supported by the current TA and the S-NSSAI that needs to perform the NSSAA.

[0366] The above Figure 10 The method describes the process in which the AMF itself determines the target NSSAI and interacts with the PCF to obtain the RSFP index corresponding to the target NSSAI when the NSSAA of all S-NSSAIs included in the pending NSSAI fails and the allowed NSSAI is empty. Alternatively, other network elements can also determine the target NSSAI and interact with the PCF to obtain the RSFP index corresponding to the target NSSAI, and send the target NSSAI and the RSFP index corresponding to the target NSSAI to the AMF. Specifically, the method can refer to the description in the following Figure 11

[0367] Figure 11 Another method for selecting a tracking area provided by the embodiments of the present application, in which the NSSF determines the target NSSAI, as Figure 11 indicated, can include:

[0368] S1101, the UE sends a registration request message to the AMF through the currently accessed RAN. Correspondingly, the AMF receives the registration request message through the RAN currently accessed by the UE.

[0369] ​Specifically, the related description of the registration request message, the execution process of S1101 is the same as S601, and is not described herein.

[0370] S1102, the AMF determines that the S-NSSAI which the RAN locates in the TA in the requested NSSAI does not support, and determines the S-NSSAI which needs to perform the NSSAA in the requested NSSAI. It should be noted that, Figure 11 In the illustrated embodiment, the original allowed NSSAI is empty, that is, there is no S-NSSAI in the original allowed NSSAI.

[0371] Specifically, the execution process of S1102 is the same as that of S1002, and is not described herein.

[0372] S1103, the AMF saves the first information in the context of the UE.

[0373] Optionally, the AMF also saves the first indication information in the context of the UE.

[0374] Specifically, the related description of the first indication information and the execution process of S1103 are the same as S603, and are not described herein.

[0375] S1104, the AMF sends a registration accept message to the UE through the RAN. Correspondingly, the UE receives the registration accept message from the AMF through the RAN.

[0376] Specifically, S1104 is the same as S604, and is not described herein. It should be understood that, Figure 11 The original allowed NSSAI included in the registration accept message in the illustrated embodiment is empty (or referred to as empty allowed NSSAI), and the registration accept message can carry the original allowed NSSAI or can not carry the original allowed NSSAI.

[0377] S1105, the AMF initiates the NSSAA procedure for each S-NSSAI included in the pending NSSAI, and obtains the result of the NSSAA procedure of each S-NSSAI.

[0378] Specifically, the execution process of the NSSAA procedure can refer to the prior art, and is not described herein.

[0379] S1106, if the results of the NSSAA procedures of all S-NSSAIs included in the pending NSSAI are all authentication and authorization failures, the AMF does not update the original allowed NSSAI determined by the AMF in S1102, which means that the allowed NSSAI (which can be referred to as a new allowed NSSAI) determined after the NSSAA procedure is empty, and there is no identification information of the network slice allowed to access the terminal.

[0380] Specifically, S1106 is the same as S1006, and will not be described here.

[0381] S1107, the AMF sends the first information and the new allowed NSSAI determined in S1006 to the NSSF. Correspondingly, the NSSF receives the first information and the new allowed NSSAI determined in S1006, and the NSSF determines the target NSSAI according to the first information and the new allowed NSSAI determined in S1006.

[0382] It should be understood that since the NSSAA procedure of the pending NSSAI in S1106 fails, the new allowed NSSAI is empty, and S1107 can be understood as the AMF sending the first information to the NSSF. Correspondingly, the NSSF receives the first information, and the NSSF determines the target NSSAI according to the first information.

[0383] Specifically, the AMF can call the service operation of the NSSF: the service interface Nnssf_NSSelection_Get sends the first information and the new allowed NSSAI determined in S1006 to the NSSF. Optionally, the AMF also sends indication information indicating that the NSSF determines the target NSSAI to the NSSF, and the NSSF determines the target NSSAI according to the first information and the new allowed NSSAI determined in S1006 in response to the indication information.

[0384] It should be understood that if the AMF stores the first information and the first indication information in S1103, the AMF can obtain the first information from the context of the UE after the NSSAA procedure of all S-NSSAIs included in the pending NSSAI is completed, and send the first information and the new allowed NSSAI determined in S1006 to the NSSF in response to the first indication information, so that the NSSF determines the target NSSAI according to the first information and the new allowed NSSAI determined in S1006.

[0385] The process of determining the target NSSAI by the NSSF is the same as that of the AMF, and is not described herein.

[0386] S1108. The NSSF sends the target NSSAI to the AMF. Correspondingly, the AMF receives the target NSSAI.

[0387] Specifically, the NSSF invokes a service operation of the NSSF: the service interface Nnssf_NSSelection_Get response (Nnssf_NSSelection_Get response) returns the target NSSAI to the AMF.

[0388] S1109. The AMF sends the target NSSAI to the PCF. Correspondingly, the PCF receives the target NSSAI from the AMF.

[0389] Specifically, S1109 is the same as S608, and is not described herein.

[0390] S1110. The PCF determines the RFSP index corresponding to the target NSSAI according to the target NSSAI, and sends the RFSP index corresponding to the target NSSAI to the AMF. Correspondingly, the AMF receives the RFSP index corresponding to the target NSSAI from the PCF.

[0391] Specifically, S1110 is the same as S609, and is not described herein.

[0392] Optionally, after the AMF obtains the target NSSAI and the RFSP index corresponding to the target NSSAI, the AMF can delete the first information stored in the context of the UE. In addition, if the AMF also stores the first indication information in S1003, after obtaining the target NSSAI and the RFSP index corresponding to the target NSSAI, the AMF can also delete the first indication information.

[0393] Since the NSSAA of all S-NSSAIs in the pending NSSAI fails, and the allowed NSSAI is empty, this registration fails, triggering the AMF to initiate a deregistration process, and releasing the context of the UE on the RAN, and in the process of releasing the context of the UE, indicating the information of the access frequency point corresponding to the target network slice to the UE, so that the UE accesses the target network slice through a new TA / cell. Specifically, the process is as described in S1111 and S1112.

[0394] S1111, the AMF initiates a deregistration procedure to the UE through the RAN. For example, the AMF sends a deregistration request to the UE through the RAN, triggering the UE to deregister / withdraw the current network registration.

[0395] S1112, a UE context release request is sent to the RAN, the UE context release request carrying the second information {target NSSAI, RFSP index corresponding to the target NSSAI}. Correspondingly, the RAN receives the UE context release request from the AMF.

[0396] The UE context release request can be used to request to release the context of the UE stored on the RAN. In addition to carrying the second information, the UE context release request can also carry the identification information of the UE and other information, which is not limited.

[0397] S1113, the RAN determines the information of the access frequency point corresponding to the target NSSAI according to the target NSSAI and the RFSP index corresponding to the target NSSAI, and sends the information of the access frequency point corresponding to the target NSSAI to the UE. Correspondingly, the UE receives the information of the access frequency point corresponding to the target NSSAI.

[0398] Specifically, S1113 is the same as S612, which is not described here.

[0399] S1114, the UE selects a target cell according to the information of the access frequency point corresponding to the target NSSAI, and initiates a registration update procedure to the target cell. For example, according to S1113, after the UE receives the information of the access frequency point corresponding to the target NSSAI from the RAN, the UE selects a cell supporting the access frequency point and camps on it, and sends a registration request message carrying a requested NSSAI to the AMF through the cell. At this time, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0400] It should be understood that in addition to including the requested NSSAI, the registration request message can also include other information, such as the identification information of the UE.

[0401] S1115, the AMF triggers other network elements to complete other procedures of the registration procedure according to the received registration request message, so as to realize the access of the UE to the network slice corresponding to the target NSSAI at the current location.

[0402] Specifically, the process can refer to the prior art and will not be described here.

[0403] Based on Figure 11 In the method shown, in the scenario where the AMF determines that the TA where the current RAN is located does not support the S-NSSAI in the requested NSSAI, and the AMF determines that the requested NSSAI contains the S-NSSAI (such as pendingNSSAI) that needs to perform NSSAA, if the NSSAA of all S-NSSAIs included in the pending NSSAI fails, and the allowed NSSAI is empty, the AMF initiates the deregistration process, obtains the target NSSAI from the NSSF, and obtains the RFSP index corresponding to the target NSSAI from the PCF, and sends the target NSSAI and the RFSP index corresponding to the target NSSAI to the RAN, and triggers the RAN to instruct the UE to select a new TA / cell access. The new TA / cell can support all network slices corresponding to the target NSSAI, ensuring that the requested NSSAI contains S-NSSAI that the current TA does not support and S-NSSAI that needs to perform NSSAA, and the UE can successfully access the network slice in the scenario.

[0404] It can be understood that the method and / or steps implemented by the mobility management network element in each of the above embodiments can also be implemented by a component (such as a chip or circuit) that can be used for the mobility management network element.

[0405] The above mainly introduces the scheme provided by the embodiments of the present application from the perspective of interaction between various network elements. Correspondingly, the present application also provides a communication device, which can be a mobility management network element in the above embodiments, or a device containing a mobility management network element, or a component that can be used for a mobility management network element. It can be understood that the communication device contains the corresponding hardware structure and / or software modules for implementing each function in order to achieve the above functions. Those skilled in the art should easily realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in hardware or computer software driven hardware depends on the specific application and design constraints of the technical solution. Professional technicians 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.

[0406] For example, taking the communication device as the mobility management network element in the above method embodiments, Figure 12A structural diagram of a communication apparatus 120 is shown. The communication apparatus 120 can be a mobility management network element, or a module or chip system for implementing the functions of the mobility management network element in the above method embodiments. As shown in Figure 12 The communication apparatus 120 can include a processing unit 1201 and a transceiver unit 1202. The transceiver unit 1202, which can also be referred to as a transceiver, is configured to implement a transceiving function, for example, a transceiving circuit, a transceiver, a transceiver, or a communication interface.

[0407] The processing unit 1201 is configured to obtain, from the identity information of the network slices requested by the terminal, the identity information of the network slices to be authenticated and authorized, initiate an authentication and authorization procedure for the network slices to be authenticated and authorized, determine the identity information of the network slices that allow the terminal to access according to the result of the authentication and authorization procedure of the network slices, and obtain the second information according to the identity information of the network slices that allow the terminal to access and the first information. The first information includes the identity information of the network slices that reject the terminal to access, or the identity information of the network slices requested by the terminal. The network slices that reject the terminal to access are the network slices that are not supported by the TA where the access network device is located in the network slices requested by the terminal.

[0408] The transceiver unit 1202 is configured to send the second information to the access network device. The second information includes the identity information of the target network slice and the radio resource information corresponding to the target network slice.

[0409] In a possible design, the processing unit 1201 is specifically configured to determine the second information according to the identity information of the network slices that allow the terminal to access and the first information. Alternatively, the transceiver unit 1202 is configured to send the identity information of the network slices that allow the terminal to access and the first information to a network slice selection function network element, and receive the second information from the network slice selection function network element.

[0410] In a possible design, the transceiver unit 1202 is specifically configured to initiate a user equipment (UE) configuration update procedure if the authentication and authorization procedure of the network slices to be authenticated and authorized is successful, and send a first message including a configuration update command and the first information to the access network device. That is, in the scenario where the authentication and authorization is successful, the second information is sent to the access network device through the configuration update procedure, thereby reducing the signaling overhead. If the authentication and authorization procedures of the network slices to be authenticated and authorized all fail, and the identity information of the network slices that allow the terminal to access is not empty, a UE context update request carrying the second information is sent to the access network device. If the authentication and authorization procedures of the network slices to be authenticated and authorized all fail, and the identity information of the network slices that allow the terminal to access is empty, a UE context release request carrying the second information is sent to the access network device.

[0411] In the above Figure 5 - Figure 11All the related content of each step involved in the method embodiments can be referred to the function description of the corresponding function module, which will not be repeated here.

[0412] In this embodiment, the communication device 120 is in the form of adopting integrated manner to divide each function module. The "module" here can refer to a specific ASIC, circuit, processor and memory executing one or more software or firmware programs, integrated logic circuit, and / or other devices that can provide the above functions. In a simple embodiment, those skilled in the art can think that the communication device 120 can adopt Figure 4 The communication device 400 shown.

[0413] For example, Figure 4 The processor 401 in the communication device 400 shown can make the communication device 400 execute the method of selecting tracking area in the above method embodiments by invoking the computer-executed instructions stored in the memory 403.

[0414] Specifically, Figure 12 The functions / implementation processes of the transceiver unit 1201 and the processing unit 1202 in the communication device 400 shown can be implemented by Figure 4 The processor 401 in the communication device 400 shown invokes the computer-executed instructions stored in the memory 403 to implement. Alternatively, Figure 12 The functions / implementation processes of the processing unit 1202 in the communication device 400 shown can be implemented by Figure 4 The processor 401 in the communication device 400 shown invokes the computer-executed instructions stored in the memory 403 to implement, Figure 12 The functions / implementation processes of the transceiver unit 1201 in the communication device 400 shown can be implemented by Figure 4 The communication interface 404 in the communication device 400 shown in the method embodiments.

[0415] Since the communication device 120 provided in this embodiment can execute the method of selecting tracking area described above, the technical effects it can obtain can be referred to the above method embodiments, which will not be repeated here.

[0416] It should be noted that one or more of the above modules or units can be implemented in software, hardware, or a combination of both. When any of the above modules or units is implemented in software, the software exists in the form of computer program instructions and is stored in the memory, and the processor can be used to execute the program instructions and implement the above method flow. The processor can be built in the SoC (system on chip) or ASIC, or be a separate semiconductor chip. The processor further includes a core for executing software instructions to perform operations or processing, and can further include necessary hardware accelerators, such as field programmable gate array (FPGA), PLD (programmable logic device), or logic circuit for implementing special logic operations. In the embodiments of the present application, the processor can be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, and can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in conjunction with the embodiments of the present application can be directly embodied as hardware processor execution or executed by a combination of hardware and software modules in the processor.

[0417] In the embodiments of the present application, the memory can be a non-volatile memory such as a hard disk drive (HDD) or a solid-state drive (SSD), and can also be a volatile memory such as a random-access memory (RAM). The memory can be any other medium capable of carrying or storing desired program code in the form of instructions or data structures and capable of being accessed by a computer, but is not limited to this. The memory in the embodiments of the present application can also be a circuit or any other device capable of implementing a storage function, for storing instructions and / or data.

[0418] When the above modules or units are implemented in hardware, the hardware can be any one or any combination of a CPU, a microprocessor, a digital signal processing (DSP) chip, a microcontroller unit (MCU), an artificial intelligence processor, an ASIC, a SoC, an FPGA, a PLD, a dedicated digital circuit, a hardware accelerator, or a non-integrated discrete device, which can run necessary software or be independent of software to execute the above method flow.

[0419] Optionally, the embodiment of the present application further provides a communication device (for example, the communication device can be a chip or a chip system), which comprises a processor, and is used for implementing the method in any of the method embodiments. In a possible design, the communication device further comprises a memory. The memory is used for storing necessary program instructions and data, and the processor can invoke the program code stored in the memory to instruct the communication device to execute the method in any of the method embodiments. Of course, the memory can also not be in the communication device. When the communication device is a chip system, the communication device can be composed of a chip, or can comprise a chip and other discrete devices, and the embodiment of the present application does not make a specific limitation here.

[0420] Optionally, the embodiment of the present application further provides a communication system, a structure diagram of which is shown in Figure 13 The communication system can comprise a terminal 130, an access network device 131, a mobility management network element 132, and can further comprise a network slice selection function network element 133. It should be noted that, Figure 13 The embodiment of the present application is not limited to Figure 13 The number of network elements included in the communication system and the number of network elements are shown in the accompanying drawings.

[0421] The mobility management network element 132 has the function of the mobility management network element in one or more of the methods shown in Figure 5 to Figure 11 The access network device 131 has the function of the first session management network element in one or more of the methods shown in Figure 5 to Figure 11 The network slice selection function network element 133 has the function of the NSSF in one or more of the methods shown in Figure 5 to Figure 11 The embodiment of the present application does not make a detailed description here.

[0422] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable devices. The computer instructions 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 instructions 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 data storage device including one or more servers, data centers, etc. integrated with the medium. The available medium can be magnetic medium (such as floppy disk, hard disk, magnetic tape), optical medium (such as DVD), or semiconductor medium (such as solid state disk (SSD)) and the like.

[0423] Although the present application is described herein in conjunction with various embodiments, it is understood that other variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from an inspection of the drawings, the disclosure, and the appended claims. The word "comprising" does not exclude other components or steps not listed in the claims, "a" or "an" does not exclude a plurality. A single processor or other unit can fulfill the functions of several means recited in the claims. Means plus function claims are understood not to limit the claimed application to the exact function recited since functions in means plus function claims are set forth in terms of means for or step for performing the recited functions rather than recited functions themselves. The reference signs in the claims shall not be construed as limiting the scope of the claims.

[0424] Although the present application is described herein in conjunction with various embodiments, it is understood that other variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from an inspection of the drawings, the disclosure, and the appended claims. The word "comprising" does not exclude other components or steps not listed in the claims, "a" or "an" does not exclude a plurality. A single processor or other unit can fulfill the functions of several means recited in the claims. Means plus function claims are understood not to limit the claimed application to the exact function recited since functions in means plus function claims are set forth in terms of means for or step for performing the recited functions rather than recited functions themselves. The reference signs in the claims shall not be construed as limiting the scope of the claims. Although the present application is described herein in conjunction with various embodiments, it is understood that other variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from an inspection of the drawings, the disclosure, and the appended claims. The word "comprising" does not exclude other components or steps not listed in the claims, "a" or "an" does not exclude a plurality. A single processor or other unit can fulfill the functions of several means recited in the claims. Means plus function claims are understood not to limit the claimed application to the exact function recited since functions in means plus function claims are set forth in terms of means for or step for performing the recited functions rather than recited functions themselves. The reference signs in the claims shall not be construed as limiting the scope of the claims.

Claims

1. A method of selecting a tracking area, characterized by, The method comprises: The mobility management network element acquires the identification information of the network slice to be authenticated and authorized from the identification information of the network slice requested by the terminal; The mobility management network element initiates the authentication and authorization procedure of the network slice to be authenticated and authorized; The mobility management network element determines the identification information of the network slice that allows the terminal to access according to the result of the authentication and authorization procedure of the network slice; The mobility management network element acquires the second information according to the identification information of the network slice that allows the terminal to access and the first information; wherein the first information comprises the identification information of the network slice that rejects the terminal to access; the network slice that rejects the terminal to access is the network slice that the tracking area where the access network device of the network slice requested by the terminal does not support; the second information comprises the identification information of the target network slice and the radio resource information corresponding to the target network slice; the identification information of the target network slice comprises part or all of the identification information of the network slice that rejects the terminal to access; or comprises part or all of the identification information of the network slice that rejects the terminal to access and part or all of the identification information of the network slice that allows the terminal to access; The mobility management network element sends the second information to the access network device; The mobility management network element acquires the second information according to the identification information of the network slice that allows the terminal to access and the first information, comprising: The mobility management network element sends the identification information of the network slice that allows the terminal to access and the first information to the network slice selection function network element, and receives the identification information of the target network slice from the network slice selection function network element; The mobility management network element sends the identification information of the target network slice to the policy control function network element, and receives the radio resource information corresponding to the target network slice from the policy control function network element.

2. The method of claim 1, wherein, The mobility management network element sends the second information to the access network device, comprising: After the terminal registration procedure, the mobility management network element sends the second information to the access network device.

3. The method of claim 2, wherein, The mobility management network element sends the second information to the access network device, comprising: If the authentication and authorization procedure of the network slice to be authenticated and authorized succeeds, the mobility management network element initiates the user equipment (UE) configuration update procedure, and sends a first message to the access network device; the first message comprises a UE configuration update command and the second information.

4. The method of claim 2, wherein, The mobility management network element sends the second information to the access network device, comprising: If the authentication and authorization procedure of the network slice to be authenticated and authorized fails, and the identification information of the network slice that allows the terminal to access is not empty, the mobility management network element sends a UE context update request to the access network device; wherein the UE context update request comprises the second information.

5. The method of claim 2, wherein, The mobility management network element sends the second information to the access network device, comprising: If the authentication and authorization procedures of the network slices to be authenticated and authorized all fail, and the identification information of the network slices allowed to be accessed by the terminal is empty, the mobility management network element sends a UE context release request to the access network device; wherein the UE context release request comprises the second information.

6. The method according to any one of claims 1 to 5, characterized in that, The method further comprises: The mobility management network element stores the first information.

7. The method according to any one of claims 1 to 5, characterized in that, The method further comprises: The mobility management network element stores first indication information; wherein the first indication information is used to indicate one or more of the following: selecting a new tracking area for the terminal, the new tracking area supporting the target network slice; or, redirecting the terminal to a tracking area or frequency band supporting the target network slice; or, obtaining the second information after the authentication and authorization procedure; The mobility management network element obtains the second information according to the identification information of the network slices allowed to be accessed by the terminal and the first information, comprising: in response to the first indication information, the mobility management network element obtains the second information according to the identification information of the network slices allowed to be accessed by the terminal and the first information.

8. The method of claim 6, wherein, The method further comprises: The mobility management network element determines that there is a network slice in the network slices requested by the terminal that is not supported by the tracking area where the access network device is located.

9. The method of claim 1, wherein, The identification information of the network slices requested by the terminal comprises the identification information of the network slices rejected to be accessed by the terminal.

10. A communications device, characterized by The communication device comprises: A processing unit configured to obtain the identification information of the network slices to be authenticated and authorized from the identification information of the network slices requested by the terminal, and initiate authentication and authorization procedures for the network slices to be authenticated and authorized; The processing unit is further configured to determine the identification information of the network slices allowed to be accessed by the terminal according to the results of the authentication and authorization procedures of the network slices, and obtain second information according to the identification information of the network slices allowed to be accessed by the terminal and first information; wherein the first information comprises the identification information of the network slices rejected to be accessed by the terminal; the network slices rejected to be accessed by the terminal are the network slices in the network slices requested by the terminal that are not supported by the tracking area where the access network device is located, the second information comprises the identification information of the target network slice and the wireless resource information corresponding to the target network slice, the identification information of the target network slice comprises part or all of the identification information in the identification information of the network slices rejected to be accessed by the terminal; or comprises part or all of the identification information in the identification information of the network slices rejected to be accessed by the terminal and part or all of the identification information in the identification information of the network slices allowed to be accessed by the terminal; A transceiver configured to send the second information to the access network device; The processing unit is specifically configured to: Send the identification information of the network slices allowed to be accessed by the terminal and the first information to a network slice selection function network element through the transceiver, and receive the identification information of the target network slice from the network slice selection function network element. The transceiver unit is configured to send the identification information of the target network slice to a policy control function network element, and receive wireless resource information corresponding to the target network slice from the policy control function network element.

11. The communication apparatus according to claim 10, wherein The transceiver unit is configured to: After the terminal registration procedure, the transceiver unit is configured to send the second information to the access network device.

12. The communication apparatus according to claim 11, wherein, The transceiver unit is configured to: If the authentication and authorization procedures of the network slices to be authenticated and authorized are successful, the transceiver unit is configured to initiate a UE configuration update procedure, and send a first message to the access network device, where the first message includes a UE configuration update command and the second information.

13. The communication apparatus according to claim 11, wherein The transceiver unit is configured to: If the authentication and authorization procedures of the network slices to be authenticated and authorized are all failed, and the identification information of the network slices allowed to be accessed by the terminal is not empty, the transceiver unit is configured to send a UE context update request to the access network device, where the UE context update request includes the second information.

14. The communication apparatus according to claim 11, wherein The transceiver unit is configured to: If the authentication and authorization procedures of the network slices to be authenticated and authorized are all failed, and the identification information of the network slices allowed to be accessed by the terminal is empty, the transceiver unit is configured to send a UE context release request to the access network device, where the UE context release request includes the second information.

15. The communication apparatus according to any one of claims 10-14, wherein, The processing unit is further configured to: store the first information.

16. The communication apparatus according to any one of claims 10-14, wherein, The processing unit is further configured to: store first indication information, where the first indication information is used to indicate one or more of the following: selecting a new tracking area for the terminal, where the new tracking area supports the target network slice; or redirecting the terminal to a tracking area or a frequency band that supports the target network slice; or obtaining the second information after an authentication and authorization procedure; The processing unit is configured to obtain the second information according to the identification information of the network slices allowed to be accessed by the terminal and the first information, in response to the first indication information.

17. The communication apparatus according to claim 15, wherein The processing unit is further configured to: determine whether there is a network slice in the network slices requested by the terminal that is not supported by a tracking area in which the access network device is located.

18. The communication apparatus according to claim 15, wherein, The identification information of the network slices requested by the terminal includes identification information of network slices that are rejected to be accessed by the terminal.

19. A communications device, characterized by The communication device includes a processor and a communication interface, and the processor and the communication interface are configured to support the communication device to perform the method of any one of claims 1-9.

20. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions, and when the computer instructions are run on a computer, the computer is caused to perform the method of any one of claims 1-9.

21. A computer program product, characterised in that, The computer program product includes computer instructions, and when the computer instructions are run on a computer, the computer is caused to perform the method of any one of claims 1-9.

22. A chip, characterized by The chip is coupled with a memory, and is configured to read and execute program instructions stored in the memory, so as to implement the method of any one of claims 1-9.

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