Method, device and system for selecting tracking area

Abstract

The embodiment of the invention provides a method, equipment and a system for selecting a tracking area, which are used for solving the problem that a terminal fails to access a network slice. The method comprises the following steps that: a mobility management network element initiates an authentication and authorization process to a network slice to be authenticated and authorized in network slices requested by a terminal, and determines identification information of the network slice to which the terminal is allowed to access according to a result of the authentication and authorization process, according to identification information of a network slice allowing terminal access and first information (such as identification information of a network slice requested by a terminal or identification information of a network slice refusing terminal access), identification information of a target network slice and wireless resource information corresponding to the target network slice are obtained and sent to an access network device. And the access network equipment triggers the terminal to successfully access the new network slice supported by the TA according to the identification information of the target network slice and the wireless resource information corresponding to the target network slice.

Description

[0001] This application is a divisional application. The original application has the application number 202110904289.X and the original application date is August 6, 2021. The entire contents of the original application are incorporated herein by reference. Technical Field

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

[0003] Network slicing (NS) is used to support logically isolated networks with specific network capabilities and characteristics. It is a key technology proposed by the 3rd Generation Partnership Project (3GPP) for addressing the differentiated network requirements of 5G mobile communication technology. Network slicing can provide isolated network environments for different application scenarios by creating virtual independent logical networks on the same network infrastructure. This allows different application scenarios to customize network functions and characteristics according to their own needs, effectively guaranteeing the quality of service (QoS) requirements of different services.

[0004] When a terminal requests access to a network slice, because the terminal blindly selects the access network device, there may be situations where the radio resources deployed in the tracking area (TA) where the access network device is located do not support the network slice requested by the terminal, thus leading to network slice access failure. How to select a suitable TA to ensure that the terminal can successfully access the network slice from that TA has become an urgent problem to be solved. Summary of the Invention

[0005] This application provides a method, device, and system for selecting a tracking area to solve the problem of terminal access failure to access network slicing.

[0006] To achieve the above objectives, the embodiments of this application adopt the following technical solutions: Firstly, a method for selecting a tracking area is provided. This method includes: 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; determining the identifier information of the network slice that the terminal is allowed to access based on the result of the authentication and authorization process; obtaining the identifier information of a target network slice and the radio resource information corresponding to the target network slice based on the identifier information of the network slice that the terminal is allowed to access and first information; and sending the identifier information of the target network slice and the radio resource information corresponding to the target network slice to an access network device, so that the access network device can successfully allow the terminal to access a new TA-supported network slice based on the identifier information of the target network slice and the radio resource information corresponding to the target network slice. The first information includes the identifier information of a network slice that the terminal is denied access to, or the identifier information of the network slice requested by the terminal; the network slice that the terminal is denied access to is a network slice in the network slice requested by the terminal that is not supported by the TA of the access network device.

[0007] Based on the method described in the first aspect, in scenarios where there are network slices awaiting authorization and authentication, after authenticating and authorizing the network slice, the identification information of the target network slice can be determined according to the authentication and authorization results, ensuring the accuracy of the determined network slices that the terminal is allowed to access. At the same time, by notifying the access network device to select a new TA that supports the target network slice for the terminal, the problem of existing terminal access failures to network slices can be solved.

[0008] In one possible design, the mobility management network element obtains the second information based on the identifier information of the network slice that the terminal is allowed to access and the first information, including any of the following methods: The mobility management network element determines the second information based on the identifier information of the network slice that the terminal is allowed to access and the first information. For example, the mobility management network element can determine the identifier information of the network slice that the terminal is denied access to based on the first information, determine the identifier information of the target network slice based on the identifier of the network slice that the terminal is denied access to and the identifier information of the network slice that the terminal is allowed to access, and receive radio resource information corresponding to the target network slice from the policy control network element. Alternatively, the mobility management network element sends the identifier information of the network slice that the terminal is allowed to access and the first information to the network slice selection function network element, and receives the second information from the network slice selection function network element.

[0009] Based on this possible design, the second information can be determined by the mobility management network element or by other network elements, thus enabling flexible and effective acquisition of the second information.

[0010] In one possible design, the mobility management network element can send a second piece of information to the access network device after the terminal registration process. This allows the terminal to complete registration and establish a connection with the network side before notifying the network side to select a new TA for the terminal, ensuring the successful execution of subsequent processes after network registration.

[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 one possible design, the mobility management network element can determine that the identification information for subsequently determining the target network slice requires the first information if it determines that the network slice requested by the terminal contains a network slice that the access network device's TA does not support (or that the TA needs to be reselected). In this case, the first information is stored, or optionally, the first indication information is stored.

[0016] In one possible design, the method further includes: after obtaining the second information, the mobility management network element can delete the stored first information or first indication information, thereby reducing the local cache pressure of the mobility management network element.

[0017] Secondly, a communication device is provided for implementing the various methods described above. This communication device can be a mobility management network element as described in the first aspect, or a device including such a mobility management network element. The communication device includes modules, units, or means corresponding to the methods described above. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the functions described above. For example, in one possible design, the communication device may include a processing unit and a transceiver unit. The processing unit is configured to obtain the identification information of the network slice to be authenticated and authorized from the identification information of the network slice requested by the terminal, initiate the authentication and authorization process for the network slice to be authenticated and authorized, determine the identification information of the network slice that the terminal is allowed to access based on the result of the authentication and authorization process, and obtain second information based on the identification information of the network slice that the terminal is allowed to access and first information; wherein, the first information includes the identification information of the network slice that the terminal is denied access to, or the identification information of the network slice requested by the terminal; the network slice that the terminal is denied access to is a network slice that the access network device in the TA of the network slice requested by the terminal does not support.

[0018] The transceiver unit is used to send second information to the access network equipment. The second information includes the identification information of the target network slice and the radio resource information corresponding to the target network slice.

[0019] Thirdly, a communication device is provided, comprising: a processor and a memory; the memory is used to store computer instructions, which, when executed by the processor, cause the communication device to perform the method described in any of the preceding aspects. The communication device may be a mobility management network element as described in the first aspect, or a device including the aforementioned mobility management network element.

[0020] Fourthly, a communication device is provided, comprising: a processor; the processor being coupled to a memory, and after reading instructions from the memory, executing the method as described in any of the preceding aspects according to the instructions. The communication device may be a mobility management network element as described in the first aspect, or a device including the aforementioned mobility management network element.

[0021] Fifthly, a computer-readable storage medium is provided that stores instructions which, when executed on a computer, enable the computer to perform the methods described in any of the preceding aspects.

[0022] In a sixth aspect, a computer program product containing instructions is provided that, when run on a computer, enables the computer to perform the methods described in any of the preceding aspects.

[0023] In a seventh aspect, a communication device (e.g., a chip or a chip system) is provided, comprising a processor for implementing the functions involved in any of the preceding aspects. In one possible design, the communication device further comprises a memory for storing necessary program instructions and data. When the communication device is a chip system, it can be constructed from chips or may include chips and other discrete devices.

[0024] The technical effects of any of the design methods in aspects two through seven can be found in the technical effects of the different design methods in aspect one above, and will not be repeated here.

[0025] Eighthly, a communication system is provided, comprising a mobility management network element and an access network device; the mobility management network element is configured to obtain the identification information of a network slice to be authenticated and authorized from the identification information of a network slice requested by a terminal, initiate an authentication and authorization process for the network slice to be authenticated and authorized, determine the identification information of a network slice that the terminal is allowed to access based on the result of the authentication and authorization process, obtain second information based on the identification information of the network slice that the terminal is allowed to access and first information, and send the second information to the access network device; wherein, the first information includes the identification information of a network slice that the terminal is denied access to, or the identification information of a network slice requested by the terminal; the network slice that the terminal is denied access to is a network slice that the access network device does not support in the TA of the network slice requested by the terminal; the access network device is configured to select a new TA for the terminal based on the second information, so that the terminal can successfully access a new network slice supported by the new TA.

[0026] The technical effects brought about by the eighth aspect are similar to those brought about by the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0027] Figure 1 Schematic diagram of different types of network slicing; Figure 2 This is a schematic diagram of the communication system provided in an embodiment of this application; 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. 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. Figure 4 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application; Figure 5 A flowchart illustrating a method for selecting a tracking region provided in an embodiment of this application; Figure 6 Interactive illustration of the method for selecting a tracking region provided in the embodiments of this application Figure 1 ; Figure 7 Interactive illustration of the method for selecting a tracking region provided in the embodiments of this application Figure 2 ; Figure 8 A schematic diagram of the interaction of the method for selecting a tracking region provided in the embodiments of this application is shown in Figure 3. Figure 9 Interactive illustration of the method for selecting a tracking region provided in the embodiments of this application Figure 4 ; Figure 10 Interactive illustration of the method for selecting a tracking region provided in the embodiments of this application Figure 5 ; Figure 11 Interactive illustration of the method for selecting a tracking region provided in the embodiments of this application Figure 6 ; Figure 12 This is a schematic diagram of the structure of a communication device 120 provided in an embodiment of this application; Figure 13 This is a schematic diagram of the structure of a communication system provided in an embodiment of this application. Detailed Implementation

[0028] To facilitate understanding of the technical solutions of the embodiments of this application, a brief introduction to the relevant technologies of this application is given below.

[0029] A network slice (NS) is a logical network with specific network characteristics. It is a key technology for meeting the differentiated network requirements of 5G mobile communication networks proposed by the 3rd Generation Partnership Project (3GPP). 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 (MTC), and Critical Machine-Type Communication (CTC). Different network slices have different network characteristics and require isolation from each other to prevent interference. Considering the different performance requirements of various network slices, the radio resources (e.g., frequencies or bands) that different network slices need to access may differ. For example, ... Figure 1 As shown, there are MBB-type network slices, a large number of MTC-type network slices, and critical MTC-type network slices. These three types of slices are isolated from each other and do not affect each other. For MBB-type network slices, the terminal needs to access this type of network slice from 2.6 GHz or 4.9 GHz; while for MTC-type network slices (a large number of MTC types or critical MTC types), the terminal needs to access this type of network from 2.6 GHz.

[0030] A network slice instance (NSI) is an instantiated network created by an operator on the infrastructure according to a network slice template. It consists of a collection of different network functional entities and physical resources. Different network slice instances are logically isolated. A network slice can instantiate 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.

[0031] Network Slice Selection Assistance Information (NSSAI): NSSAI is used to indicate one or more network slices. NSSAI can include multiple Single Network Slice Selection Assistance Information (S-NSSAI). A network slice is identified by an S-NSSAI. An S-NSSAI consists of a slice / service type (SST) and a slice differentiator (SD). SST and SD can be defined by the standard or defined by the operator; SD is optional information supplementing SST to distinguish multiple network slices with the same SST. SD can be used to characterize the affiliation of network slices. The types and functions of NSSAI defined in the 23.501 standard are shown in Table 1.

[0032] It should be noted that, in the embodiments of this application, S-NSSAI can be simply referred to as the identification information of a network slice, and NSSAI can be simply referred to as a collection of identification information of one or more network slices.

[0033] Table 1

[0034] A tracking area (TA) can be the location information of a terminal. Multiple TAs can form a TA list, which is assigned to a single terminal. When a terminal moves within the TA list, it does not need to perform TA updates, thus reducing frequent interactions with the network. A TA can be configured at the cell level; multiple cells can be configured with the same TA, and a cell can only belong to one TA. One or more network slices can be deployed within a TA. If a TA deploys a network slice, then all cells within that TA support that network slice, and the terminal can access the network slice from any cell within that TA. A network slice that a TA does not support can be described as the TA being unable to access that network slice; TA not supporting a network slice can be understood as not supporting terminal access to that network slice through that TA. The mapping between TAs and the network slices supported by a TA can be pre-stored in the mobility management network element.

[0035] It should be understood that the embodiments of this application do not limit the naming of the tracking region or the corresponding English abbreviation. The tracking region described in this application can be replaced with "TA" or other names, such as "first region," without limitation. The method provided in the embodiments of this application is described below with the tracking region as "TA." In addition, the network slices that "TA does not support" in this application can be understood as "TA does not support / cannot use the S-NSSAI of the network slice," or "TA does not support / cannot use S-NSSAI," and the S-NSSAI corresponds to the network slice that "TA does not support / cannot use."

[0036] For example, Table 2 shows the correspondence between TAs and the S-NSSAIs of the network slices supported by the TAs. As shown in Table 2, assume that three types of network slices are deployed in the network, and the S-NSSAIs of these three types of network slices are S-NSSAI-1, S-NSSAI-2 and S-NSSAI-3, respectively. Among them, the TAs supporting S-NSSAI-1 include TA1, TA2 and TA4, the TAs supporting S-NSSAI-1 include TA2, TA3 and TA4, and the TAs supporting S-NSSAI-3 include TA1, TA3 and TA4.

[0037] Table 2

[0038] However, in actual deployment scenarios, network slices and frequencies can have a corresponding relationship. The frequency corresponding to a network slice can be the frequency point for accessing that network slice. In this application, this frequency point can be referred to as the access frequency point. That is, the terminal can access the network slice through a specified frequency band(s) (or the frequency point corresponding to the network slice). However, the terminal is unaware of the network slice deployment status, and the terminal blindly selects cells to camp on. This will result in the frequency corresponding to the cell selected by the terminal not supporting the network slice that the terminal wants to access, thus failing to meet the terminal's service requirements.

[0039] To ensure that the cell selected by the terminal supports the network slice it wants to access, the current 3GPP standard proposes the following method: The mobility management element (MLE) determines whether the requested NSSAI contains the S-NSSAI of a network slice that the current TA (Targeting Technology) does not support, or vice versa. If the MLE determines that the requested NSSAI contains the S-NSSAI of a network slice that the current TA is unavailable, then the terminal is denied access to that network slice. The S-NSSAI of that network slice is added to the NSSAI of the network slice to which the terminal is denied access, generating a rejected NSSAI and a rejection reason value: "Current TA does not support / Current TA is unavailable". The MLE then obtains the target NSSAI based on the rejected NSSAI. The obtained target NSSAI can contain some or all of the S-NSSAI from the NSSAI of the network slice to which the terminal is denied access, and some or all of the S-NSSAI from the NSSAI of the network slice to which the terminal is allowed access. The mobility management network element obtains the Radio Access Technology / Frequency Selection Priority (RAT / RFSP) index corresponding to the target NSSAI based on the target NSSAI, and sends the target NSSAI and RFSP index to the access network device. This triggers the access network device to determine the target TA (where the target TA 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 where the target TA is located (which can be called the target cell) through the radio resource control (RRC) redirection procedure.

[0040] For example, suppose network slice 1 and network slice 2 correspond to frequencies F1 and F2 respectively, TA1 supports network slice 1, and TA2 supports both network slice 1 and network slice 2. The terminal accesses the cell of TA1 through F1 via the cell selection mechanism. At this time, the requested NSSAI sent by the terminal corresponds to both network slice 1 and network slice 2. However, TA1 does not support network slice 2 and only supports network slice 1. Therefore, the mobility management element rejects the terminal's access to network slice 2. In this case, allowed NSSAI includes the S-NSSAI of network slice 1; rejected NSSAI includes the S-NSSAI of network slice 2. To enable the terminal to select TA2 cell to access network slice 1 and network slice 2, the mobility management network element obtains the target NSSAI (including rejected NSSAI (i.e., S-NSSAI of network slice 2) and allowed NSSAI (i.e., S-NSSAI of network slice 1)), and further obtains the RFSP index corresponding to the target NSSAI. The target NSSAI and RFSP index are sent to the access network device. The access network device determines whether the frequency points of the surrounding cells meet the conditions based on the RFSP index. If they do, the access network device performs an RRC release procedure to redirect the terminal to the cell of TA2, and accesses network slice 1 and network slice 2 through the cell of TA2, thus meeting the terminal's service requirements and improving the terminal's service experience.

[0041] However, the existing 3GPP standard does not consider scenarios where requested NSSAI includes both S-NSSAI that is not currently supported by the TA and S-NSSAI that requires the execution of the NSSAA procedure, and does not provide solutions to the following problems: Question 1: During the registration process, the allowed NSSAI determined by the mobility management element includes the S-NSSAI for which the NSAA process does not need to be executed. It can be understood that the S-NSSAI included in the allowed NSSAI at this time is a temporary value. After the NSAA process ends, the mobility management element may update the allowed NSSAI, such as adding the S-NSSAI of the successful NSAA process to the allowed NSSAI. The change of the updated allowed NSSAI further affects the determination of the target NSSAI. Therefore, it is inaccurate to determine the target NSSAI based on the allowed NSSAI determined before the NSAA process is executed.

[0042] Assume that the requested NSSAIs include S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and these three S-NSSAIs are included in the NSSAIs subscribed to by the UE. The RAN currently accessed by the UE is TA3. If TA3 supports S-NSSAI-2 and S-NSSAI-3, then the rejected NSSAIs include S-NSSAI-1. If S-NSSAI-3 supported by TA3 does not require NSAA execution, but S-NSSAI-2 supported by TA3 does require NSAA execution, then the determined allowed NSSAIs include {S-NSSAI-3}, the pending NSSAIs include {S-NSSAI-2}, and the rejected NSSAIs include {S-NSSAI-1}. According to existing methods, before the NSAA process, the target NSSAI is determined based on the allowed NSSAIs including {S-NSSAI-3} and the rejected NSSAIs including {S-NSSAI-1}. Since TA1 and TA4 both support S-NSSAI-1 and S-NSSAI-3, the target NSSAI is determined to include {S-NSSAI-1, S-NSSAI-3}. According to Table 2, the terminal can access both S-NSSAI-1 and S-NSSAI-3 simultaneously via TA1 or TA4. If the radio resource information corresponding to the target NSSAI determined by the network side is supported by TA1, the terminal can access both S-NSSAI-1 and S-NSSAI-3 via TA1. However, the terminal still cannot access S-NSSAI-2 because TA1 does not support S-NSSAI-2.

[0043] In contrast, if the NSSAA procedure is completed and the NSSAA of S-NSSAI-2 is successfully executed, allowing the UE to access the network slice corresponding to S-NSSAI-2, the currently allowed NSSAIs include {S-NSSAI-2, S-NSSAI-3}, and the rejected NSSAIs include {S-NSSAI-1}. If the method of the embodiments of this application described later is used, the target NSSAI is determined based on the allowed NSSAIs including {S-NSSAI-2, S-NSSAI-3} and the rejected NSSAIs including {S-NSSAI-1}. Since TA4 supports S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 simultaneously, the target NSSAIs are 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 simultaneously through TA4. At this point, the terminal can access three network slices simultaneously via TA4, which satisfies all of the terminal's needs.

[0044] It can be seen that the target NSSAI determined by the network side is different before and after the NSSAA process. If the network side does not consider the result of the NSSAA process, the target NSSAI determined before the NSSAA process will be inaccurate and cannot meet the user's access needs well.

[0045] Question 2: In scenarios where the registration process is terminated due to NSSAA process failure, if the accurate target NSSAI and RFSP index are not determined, the terminal may still select the wrong TA when registering again, and thus fail to successfully access the network slice.

[0046] Assume that the requested NSSAI includes S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and these three S-NSSAIs are included in the NSSAIs subscribed to by the UE. The RAN currently accessed by the UE is TA3, as shown in Table 2. TA3 supports S-NSSAI-2 and S-NSSAI-3, so the rejected NSSAI includes S-NSSAI-1. If both S-NSSAI-2 and S-NSSAI-3 supported by TA3 require NSAA execution, then the determined allowed NSSAI is empty. In this application, an empty allowed NSSAI can be represented as allowed NSSAI{empty}. According to existing methods, before the NSAA process, the target NSSAI is determined based on allowed NSSAI{empty} and the rejected NSSAI including {S-NSSAI-1}. Since there are no S-NSSAIs in allowed NSSAI, the target NSSAI includes {S-NSSAI-1}. If the radio resource information corresponding to the targetNSSAI determined by the network side is supported by TA1, then the terminal can access S-NSSAI-1 through TA1. However, the terminal still cannot access S-NSSAI-2 and S-NSSAI-3 because TA1 does not support S-NSSAI-2 and S-NSSAI-3.

[0047] If the NSSAA process ends and both S-NSSAI-2 and S-NSSAI-3 fail, the network slices allowed for UE access remain unchanged and are still empty (allowed NSSAI). The network will then initiate a deregistration process for the terminal. Since the terminal can only obtain radio resource information supported by TA1, it still does not know which TA supports S-NSSAI-2 and S-NSSAI-3. Therefore, when the terminal registers again, it may still select the wrong TA, resulting in the inability to access S-NSSAI-2 and S-NSSAI-3.

[0048] It can be seen that the target NSSAI determined by the network side before the NSSAA process is inaccurate, because if the deregistration process is initiated for the terminal after the NSSAA process, the terminal can only access the network slices included in the target NSSAI, and cannot access the network slices that failed in the NSSAA process.

[0049] To address the aforementioned technical problems, this application provides a method: A mobility management network element initiates an authentication and authorization process for a network slice in a network slice requested by a terminal, and determines the identifier information of the network slice that the terminal is allowed to access based on the result of the authentication and authorization process. Based on the identifier information of the network slice that the terminal is allowed to access and first information (such as the identifier information of the network slice requested by the terminal or the identifier information of the network slice that denies the terminal access), the element obtains the identifier information of the target network slice and the radio resource information corresponding to the target network slice, and sends this information to the access network device. This allows the access network device to trigger the terminal to successfully access a new TA-supported network slice based on the identifier information of the target network slice and the radio resource information corresponding to the target network slice. Specifically, the allowed NSSAI is determined by referring to the result of the NSSAA process, ensuring the accuracy of the determined target NSSAI, and thus ensuring that the terminal successfully accesses the network slice corresponding to the target NSSAI through the new TA. Specifically, the implementation process of this method can be referred to below. Figures 5-11 As described in [the text].

[0050] It should be understood that in the embodiments of this application, the identification information of the network slice that the terminal is denied access to in the first information may be the rejected NSSAI shown in Table 1, that is, the rejected NSSAI whose reason for rejection is that the current TA does not support it.

[0051] Optionally, the first information can be stored on the mobility management network element (MLE), so that the MLE can obtain the identification information of the network slice that was denied terminal access before the authentication and authorization process based on the locally stored first information, and then determine the identification information of the target network slice based on the identification information of the network slice that denied terminal access, in order to solve the following problem: the rejected NSSAI has been sent to the terminal in the registration acceptance message, but because the MLE does not save the rejected NSSAI, the MLE cannot obtain the rejected NSSAI after the NSAA process, and therefore cannot obtain the target NSSAI based on the rejected NSSAI.

[0052] The method for selecting a tracking region provided in the embodiments of this application will now be described with reference to the accompanying drawings: It should be understood that the network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0053] The following is based on Figure 2Taking the communication system shown as an example, the method for selecting the tracking area provided in the embodiments of this application will be described.

[0054] like Figure 2 The diagram illustrates a communication system 20 provided in an embodiment of this 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 may further include a network slice selection function network element, a data management network element, a policy control network element, an authentication and authorization network element, etc.

[0055] In this scenario, an access network device can cover one or more access points (TAs). A TA can include one or more cells, and each cell can correspond to an access frequency. One or more network slices can be deployed within a TA. A terminal can access the network slice supported by a specific cell within that TA using its corresponding access frequency. For example, if the coverage area of ​​the same access network device includes TA1 and TA2, and TA1 includes cell 1, supports network slice 1, and uses frequency F1, the terminal can access network slice 1 via F1. TA2 includes cell 2, uses frequency F2, and supports both network slice 1 and network slice 2, the terminal can access both via F2. In this scenario, the terminal does not need to change its access network device; it only needs to access the network slice from another TA supported by that access network device. Another example is that access network device 1's coverage area includes TA1, and access network device 2's coverage area includes TA2. TA1 includes cell 1, which supports network slice 1. Cell 1 uses frequency F1, and the terminal can camp on cell 1 under TA1 and access network slice 1 via F1. TA2 includes cell 2, which uses access frequency F2. TA2 supports network slice 2, and the terminal can camp on cell 2 under TA2 via F2 and access network slice 2. This can be understood as the terminal needing to change its access network equipment to access different network slices in this scenario. It should be noted that this application does not limit whether the terminal needs to change its access network equipment to access the target network slice corresponding to the target NSSAI.

[0056] The following is about Figure 2 The network elements in the system shown are introduced below: Mobility management network elements are mainly used for mobility management in mobile networks, such as user location updates, user registration with the network, and user handover. In 5G communication systems, mobility management network elements can be access and mobility management function (AMF) network elements. Namf is a service-based interface provided by the AMF network element. The AMF network element can communicate with other network functions through Namf. In future communications such as 6th generation (6G) communications, mobility management network elements can still be AMF network elements, or they may have other names. This application does not limit this.

[0057] A terminal can be a device used to implement wireless communication functions, such as a terminal or a chip that can be used in a terminal. It can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; it can also be deployed on water (such as ships); and it can also be deployed in the air (such as airplanes, balloons, and satellites). Among them, the terminal can be user equipment (UE), access terminal, terminal unit, terminal station, mobile station, mobile station, remote station, remote terminal, mobile device, wireless communication device, terminal agent, or terminal device in 5G network or future evolved public land mobile network (PLMN). Access terminals can be cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices or wearable devices, virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical care, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, etc. Terminals can be mobile or fixed.

[0058] Access network equipment (or radio access network (RAN) equipment) is a device that provides wireless communication capabilities to terminals. Access network equipment includes, but is not limited to: next-generation base stations (gnodeB, gNB) in 5G, evolved node B (eNB), radio network controller (RNC), node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved nodeB, or homenode B, HNB), baseband unit (BBU), transmitting and receiving point (TRP), transmitting point (TP), mobile switching center, etc.

[0059] The network slice selection function (NSSF) network element is used to select network slices for terminals. In 5G communication systems, the NSSF network element can be a network slice selection function (NSSF) network element, where NSSF is a service-based interface provided by the NSSF network element, allowing the NSSF network element to communicate with other network functions. In future communication such as 6G communication, the NSSF network element can still be an NSSF network element, or it may have other names; this application does not limit this.

[0060] Data management network elements can be used to store user data, such as user subscription data, authentication or authorization data, etc. Specifically, network storage network elements can be unified data management (UDM), network repository function (NRF), or unified data repository (UDR), etc.

[0061] Policy control network elements can be used to provide policies to mobility management network elements and session management function network elements, such as quality of service policies, slice selection policies, RFSP indexes, etc.

[0062] Authentication and authorization network elements can be used for authentication, authorization, and accounting of network slices, etc. Specifically, authentication and authorization network elements can be authentication, authorization, and accounting (AAA) network elements, etc.

[0063] It should be noted that, Figure 2 This is merely an illustrative architecture diagram, except... Figure 2 In addition to the functional units shown, the system may also include other functional network elements, such as operation and management (O&M) network elements, etc., which are not limited in this embodiment. Furthermore, Figure 2 The names of the various devices in the text are not restricted, except... Figure 4 In addition to the names shown, each device can also be named with other names, such as replacing them with network element names that have the same or similar functions, without restriction.

[0064] in, Figure 2 The system shown can be a 3rd generation partnership project (3GPP) communication system, such as a 4th generation (4G) communication system, a long term evolution (LTE) system, a 5th generation (5G) communication system, a new radio (NR) system, a vehicle-to-everything (V2X) system, an Internet of Things (IoT) system, or any other next-generation communication system, without limitation.

[0065] by Figure 2 The communication system shown is Figure 3a or Figure 3b Taking the 5G communication system shown as an example, such as Figure 3a As shown or Figure 3bAs shown, a 5G communication system may include a UE, a data network (DN), and an operator network. The operator network may include one or more of the following network elements: authentication server function (AUSF), network slice-specific authentication and authorization function (NSSAAF), network slice admission control function (NSACF), NSSF, service communication proxy (SCP), network exposure function (NEF), policy control function (PCF), unified data management (UDM), network repository function (NRF), application function (AF), access and mobility management function (AMF), session management function (SMF), radio access network (RAN), and user plane function (UPF).

[0066] Operators can deploy different network functions within a network slice according to the network slice template, such as... Figure 3a or Figure 3b The network elements SMF, UPF, and PCF are used to meet the network performance and functional requirements specified in the network slicing template. When a terminal requests access to a certain network slice, the network functions that support that network slice provide services to the terminal.

[0067] in, Figure 3a A schematic diagram of a 5G communication system based on service-oriented interfaces; Figure 3a The control plane network elements shown, such as AMF, SMF, and NSSF, can interact using service-oriented interfaces. For example, the service-oriented interface provided by AMF can be Namf; the service-oriented interface provided by SMF can be Nsmf; the service-oriented interface provided by PCF can be Npcf; and the service-oriented interface provided by NSSF can be Nnssf.

[0068] 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.

[0069] 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. 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).

[0070] 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.)

[0071] Processor 401 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits used to control the execution of programs according to the present application.

[0072] Communication line 402 may include a path for connecting different components.

[0073] The communication interface 404 can be used to communicate with other devices or communication networks, such as Ethernet, RAN, and wireless local area networks (WLAN). For example, the communication interface 404 can be a transceiver or similar device. Optionally, the communication interface 404 can also be a transceiver circuit located within the processor 401, used to implement the processor's signal input and signal output.

[0074] Memory 403 can be a device with storage function. For example, it can be read-only memory (ROM) or other types of static storage devices capable of storing static information and instructions; random access memory (RAM) or other types of dynamic storage devices capable of storing information and instructions; electrically erasable programmable read-only memory (EEPROM); compact disc read-only memory (CD-ROM) or other optical disc storage; optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.); magnetic disk storage media or other magnetic storage devices; or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited to these. Memory can exist independently and be connected to the processor via communication line 402. Memory can also be integrated with the processor.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] The aforementioned communication device 400 may sometimes be referred to as a communication equipment, which can be a general-purpose device or a special-purpose device. For example, the communication device 400 may be a desktop computer, a portable computer, a network server, a handheld computer (PDA), a mobile phone, a tablet computer, a wireless terminal, an embedded device, the aforementioned terminal, the aforementioned network equipment, or something else with... Figure 4 Devices with similar structures. This application does not limit the type of communication device 400. Furthermore, Figure 4 The structural composition shown does not constitute a limitation on the communication device, except... Figure 4 In addition to the components shown, the communication device may include more or fewer components than illustrated, or combine certain components, or have different component arrangements.

[0080] In this embodiment of the application, the chip system may be composed of chips or may include chips and other discrete devices.

[0081] The following is combined Figure 2 The communication system shown describes the method for selecting a tracking area provided in the embodiments of this application. In the following embodiments, each device may have... Figure 4 The components shown, and the actions, terms, etc. involved in the various embodiments, can be referenced to each other. The message names or parameter names in the messages between devices in the various embodiments are just examples, and other names can be used in specific implementations without limitation. In addition, the terms "first" and "second" in the embodiments of this application are used to distinguish different objects, rather than to describe a specific order of objects. The embodiments of this application do not limit the attributes of the different objects represented by "first" and "second".

[0082] like Figure 5 The image shows a method for selecting a tracking region provided in an embodiment of this application. The method includes the following steps: In S500, the terminal sends a registration request message to the mobility management network element through the access network equipment it accesses. Correspondingly, the mobility management network element receives the registration request message.

[0083] The terminal can be Figure 2 Any terminal that initiates the registration process, for example, the terminal could be Figure 2 Terminal 1 or Terminal 2 in the network. The access network device can be the access network device currently providing access services to the terminal. The terminal can send a registration request message to the mobility management network element through this access network device. The mobility management network element can be... Figure 2 The mobility management network element manages the access network equipment and establishes non-access stratum (NAS) connections with terminals.

[0084] The registration request message may include the identifier information of the network slice requested by the terminal, as well as other information such as the terminal's identifier. The network slice requested by the terminal may be the network slice that the terminal requests to access, or the network slice that the terminal requests to access through the TA (Transmission Access Node) where the access network device is located. The network slice requested by the terminal may include one or more network slices, without limitation. It should be noted that, in this embodiment, the TA where the access network device currently accessed by the terminal is located can be referred to as the current TA, which will be consistently stated here and will not be repeated below.

[0085] In this embodiment of the application, the identification information of a network slice can be used to identify the network slice. The identification information of a network slice can be the S-NSSAI of the network slice, the identification information of a network slice requested by the terminal can be the requested NSSSAI of the terminal, the identification information of a network slice pending authentication and authorization can be the pending NSSAI, the identification information of a network slice subscribed to by the terminal can be the subscribed NSSAI of the terminal, and the identification information of a network slice that the terminal is allowed to access can be the allowed NSSAI of the terminal. The description of these NSSAIs can be referred to Table 1 above, and will not be repeated here.

[0086] 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.

[0087] Taking the network slice identifier S-NSSAI as an example, S501 can be understood as the mobility management network element obtaining the pending NSSAI from the requested NSSAI.

[0088] For example, after receiving a registration request message, the mobility management network element (MMU) determines whether to allow access to the requested network slice for each network slice requested by the terminal based on the network slice subscribed to by the terminal. If the MMU determines that the requested network slice is subscribed to, but the requested network slice is not supported or is unavailable in the current TA (Targeting Association), then the MMU determines that the terminal is not allowed to access the requested network slice, i.e., it refuses the terminal's access to the requested network slice. The reason for refusal can include that the current TA does not support it (or the current TA is unavailable). This type of network slice is considered a network slice that is refused access by the terminal. Assuming the identification information of the network slice is S-NSSAI, the identification information of this type of network slice, where the reason for refusal is that the current TA does not support it, belongs to rejected NSSAI and is included in rejected NSSAI. It should be understood that the rejected NSSAI mentioned in this embodiment refers to the S-NSSAI of the network slice for which the reason for refusal is that the current TA does not support it.

[0089] If the mobility management element determines that the network slice requested by the terminal is permitted by the subscription, and that the requested network slice is supported or available in the current TA, the mobility management element further determines whether the network slice needs to undergo a network slice specific authentication and authorization (NSSAA) process. The result of this determination can lead to the following two situations: 1) If a network slice does not require authentication and authorization, then this type of network slice is considered a network slice that allows terminal access. Assuming the identifier of a network slice is S-NSSAI, then the identifier of this type of network slice can be directly included in the allowed NSSAI. It should be understood that in this embodiment, the allowed NSSAI determined before the authentication and authorization process can be referred to as the original allowed NSSAI; this is a unified explanation here and will not be repeated below.

[0090] 2) If a network slice requires authentication and authorization, it is considered a candidate / pending network slice, awaiting authentication and authorization. In this case, after the registration process, the mobility management network element can initiate the authentication and authorization process for the network slice awaiting authorization. If the authentication and authorization of a network slice is successful, the terminal is allowed to access the network slice, and the identifier information of that network slice is added to the allowed NSSAI, i.e., the allowed NSSAI is updated. If the authentication and authorization of a network slice fails, the terminal is not allowed (or is denied) access to that network slice, with the reason for denial being: authentication and authorization failed.

[0091] In this embodiment, the mobility management network element (MMI) can pre-store a TA list, which includes one or more TAs. The MMI also stores the correspondence between TAs and the identification information of network slices supported by those TAs. If the identification information of the network slice requested by the terminal is not included in the identification information of network slices supported by the TA, it is determined that the TA does not support that network slice. For example, assuming the MMI stores {TA1, S-NSSAI-1}, {TA2, S-NSSAI-1, S-NSSAI-2}, and the terminal requests S-NSSAI-1 and S-NSSAI-2 through the RAN, and the TA where the RAN is located is TA1, then according to the correspondence stored in the MMI, it can be determined that TA1 does not support S-NSSAI-2, that is, the current TA does not support S-NSSAI-2. For example, suppose the mobility management network element stores {TA1, S-NSSAI-1}, {TA2, S-NSSAI-1, S-NSSAI-2}, {TA3, S-NSSAI-2, S-NSSAI-3}, and the terminal requests S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3 through the RAN. The TA where the RAN is located is TA3. Based on the correspondence stored in 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.

[0092] In this embodiment, the relevant information of the network slice subscribed by the terminal can be pre-stored in the terminal's subscription data. The terminal's subscription data may include the identifier information of the network slice subscribed to by the terminal, and indication information regarding whether each subscribed network slice requires NSSAA (Network Slice Authentication and Authorization) processing. The correspondence between the identifier information of the network slice subscribed to by the terminal and the indication information regarding whether network slice authentication and authorization processing is required can be included in the terminal's subscription data in list form. The terminal's subscription data can be pre-stored in a data storage network element, such as in a UDM (Uniform Depository Management). The mobility management network element can obtain the terminal's subscription data from the data storage network element.

[0093] In this embodiment, if the network slice requested by the terminal is included in the network slice subscribed to by the terminal, then the network slice requested by the terminal can be considered to be subscribed to and allowed. If the identification information of the network slice requested by the terminal is included in the terminal's subscription data, and the terminal's subscription data indicates that authentication and authorization of the network slice are required, then the identification information of the network slice is determined as the identification information of the network slice to be authenticated and authorized.

[0094] For example, taking the network slice identifier S-NSSAI as an example, Table 3 below shows the correspondence between S-NSSAI and the indication information regarding whether the network slice needs to perform network slice authentication and authorization. It should be understood that Table 3 is merely an exemplary table, and other S-NSSAIs may be included besides those shown in Table 3, without limitation. As shown in Table 3, the NSSAIs signed by the terminal include S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, where S-NSSAI-1 and S-NSSAI-2 require network slice authentication and authorization, while S-NSSAI-3 does not. Assuming the network slice identifier information requested by the terminal includes S-NSSAI-2 and S-NSSAI-3, the mobility management network element can use S-NSSAI-2 as an index to look up Table 3 to determine that S-NSSAI-2 needs to perform network slice authentication and authorization, and use S-NSSAI-3 as an index to look up Table 3 to determine that S-NSSAI-3 does not need to perform network slice authentication and authorization. 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.

[0095] Table 3

[0096] Optionally, after executing S501, the mobility management network element sends a registration accept message to the terminal. This registration accept message corresponds to the registration request message in S500. The registration accept message may include the identification information of network slices that the terminal is allowed to access (e.g., the original allowed NSSAI), the identification information of network slices that the terminal is denied access to (e.g., rejected NSSASI), and the identification information of network slices that are pending authentication and authorization (e.g., pending NSSAI). This allows the terminal to know which network slices in its requested network slices are allowed to access, which are denied access, and which are pending authentication and authorization, thus completing the registration process initiated by the terminal in S500.

[0097] In this embodiment, the original allowed NSSAI can refer to the NSSAI that belongs to the terminal's subscribed NSSAI in the terminal's requested NSSAI and does not require authentication or authorization. It is the allowed NSSAI stored on the mobility management network element after the registration process is completed. The name of the original allowed NSSAI is not limited and can also be named the old allowed NSSAI or the first allowed NSSAI.

[0098] Optionally, the mobility management network element stores the identification information of the network slices that the terminal is allowed to access in the context of the terminal (i.e., stores the original allowed NSSI), so that after the authentication and authorization process is completed, the stored identification information of the network slices that the terminal is allowed to access can be updated according to the authentication and authorization result.

[0099] Optionally, the mobility management network element may also store first information, which may include the identifier information of the network slice requested by the terminal or the identifier information of the network slice to which the terminal is denied access. For example, the first information may also be stored in the context of the terminal so as to determine the identifier information of the target network slice based on the stored first information and the updated identifier information of the network slice to which the terminal is allowed access.

[0100] In this embodiment, if the mobility management network element determines that the identification information of the network slice requested by the terminal contains identification information of a network slice that denies the terminal access, the mobility management network element may be triggered to store the first information on the mobility management network element.

[0101] Furthermore, if the mobility management element determines that the identification information of the network slice requested by the terminal contains identification information of a network slice that denies the terminal access, the mobility management element can also generate first indication information. This first indication information 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 frequency band that supports the target network slice; or after the authentication and authorization process, obtaining second information for the terminal so that after the authentication and authorization process, the mobility management element, in response to the first indication information, determines the identification information of the target network slice based on the first information and the updated identification information of the network slice that allows the terminal access.

[0102] Furthermore, after the mobility management network element generates the first instruction information, the first instruction information is stored in the context of the terminal.

[0103] In this application, the naming of the first instruction information is not limited. The first instruction information may also be called a flag or other names, without restriction.

[0104] S502. The mobility management network element initiates the authentication and authorization process for the network slice to be authenticated and authorized.

[0105] Taking the identification information of network slice as S-NSSAI as an example, S502 can be understood as the mobility management network element initiating an authentication and authorization process for S-NSSAI in pending NSSAI.

[0106] For example, the authentication and authorization process initiated by the mobility management network element for a network slice to be authenticated and authorized may 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 feeding 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 existing technologies and will not be elaborated further.

[0107] S503. The mobility management network element determines the identification information of the network slice that the terminal is allowed to access based on the result of the network slice authentication and authorization process.

[0108] Taking the network slice identifier S-NSSAI as an example, S503 can be understood as the mobility management network element determining the allowed NSSAI based on the authentication and authorization process of the pending S-NSSAI. It should be understood that the network slice identifier determined in S503 that allows terminal access can refer to a new allowed NSSAI, which is the allowed NSSAI determined based on the authentication and authorization process. The name of the new allowed NSSAI is not restricted; it can also be named a second allowed NSSAI.

[0109] In this embodiment, the result of the network slice authentication and authorization process may include successful authentication or authorization of the network slice, or failure of authentication and authorization of the network slice. The mobility management network element determines the identification information of the network slice that the terminal is allowed to access based on the result of the network slice authentication and authorization process, which may include the following two examples: In one example, if network slice authentication and authorization are successful, the mobility management element updates the identifier information of the network slice that the terminal is allowed to access. Specifically, the mobility management element adds the identifier information of the successfully authenticated network slice to the identifier information of the network slices allowed to access stored in the terminal's context. Taking the network slice identifier information as S-NSSAI as an example, if the S-NSSAI contained in pending NSSAI is successfully authenticated and authorized, the original allowed NSSAI is updated, that is, the successfully authenticated S-NSSAI contained in pending NSSAI is added to the original allowed NSSAI. Specifically, this scenario is as follows: Figure 6 or Figure 7 As shown in the image.

[0110] In another example, if network slice authentication fails, only the identifiers of network slices that do not require authentication from the identifier information requested by the terminal are identified as network slices allowed for terminal access. Taking S-NSSAI as an example, this means that if all S-NSSAIs included in the pending NSSAI fail authentication, the original allowed NSSAI remains unchanged. Specifically, this scenario is as follows: Figures 8-11 As shown in the image.

[0111] For example, suppose the pending NSSAI includes S-NSSAI-2, and the original allowed NSSAI includes S-NSSAI-3. If S-NSSAI-2 is successfully authenticated and authorized, the original allowed NSSAI is updated to the new allowed NSSAI, which includes both S-NSSAI-2 and S-NSSAI-3. If S-NSSAI-2 fails to authenticate and authorize, the original allowed NSSAI remains unchanged, still including S-NSSAI-3.

[0112] S504. The mobility management network element obtains the second information based on the identification information of the network slice that the terminal is allowed to access, as determined in S503, and the first information; the first information includes the identification information of the network slice that the terminal is denied access to, or the identification information of the network slice requested by the terminal.

[0113] In this embodiment of the application, the network slice that the terminal is denied access to can be a network slice that the access network device in the TA does not support.

[0114] In this embodiment, the second information may include the identification information of the target network slice and the radio resource information corresponding to the target network slice. The radio resource information corresponding to the target network slice can be used to indicate the access frequency point for accessing the target network slice. For example, the radio resource information corresponding to the target network slice may be a radio access technology (RAT) / frequency selection priority (RFSP) index corresponding to the target network slice. This RFSP index can indicate the access frequency point, which can support the target network slice. The access frequency point corresponding to the RFSP index can be pre-stored in access network equipment or policy control network elements, such as RAN or PCF.

[0115] Taking S-NSSAI as the identifier of a network slice and RFSP index as the radio resource information corresponding to the target network slice as the identifier of the network slice to which the terminal access is denied, the identifier of the network slice can be rejected NSSAI, and the identifier of the target network slice can be target NSSAI. S504 can be replaced by the mobility management element obtaining the target NSSAI and RFSP index based on the allowed NSSAI and requested NSSAI determined in S503, or obtaining the target NSSAI and RFSP index based on the allowed NSSAI and rejected NSSAI.

[0116] In this embodiment, the first information can be stored on a mobility management network element, such as in S501, where the first information is stored in the context of the terminal on the mobility management network element. After S503 is executed, the mobility management network element can obtain the first information from the local context and obtain the second information based on the first information and the identifier information of the network slice that the terminal is allowed to access. Optionally, after obtaining the second information, the mobility management network element can delete the stored first information.

[0117] Optionally, after S503 is executed, the mobility management network element can respond to the first indication information and obtain the second information based on the identifier information of the network slice that the terminal is allowed to access, as determined in S503, and the first information. That is, the first indication information can serve as a triggering 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 locally 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.

[0118] For example, the mobility management network element obtaining the second information based on the identification information of the network slice that the terminal is allowed to access, as determined in S503, and the first information may include the following two possible designs: In one possible design, the mobility management network element can determine the second information itself based on the identifier information of the network slice that the terminal is allowed to access and the first information. Specifically, this process can be referred to... Figure 6 , Figure 8 or Figure 10 As described in [the text].

[0119] In another possible design, other network elements can determine the second information based on the identifier information of the network slice that the terminal is allowed to access and the first information, and then feed back the determined second information to the mobility management network element. For example, the mobility management network element can send the identifier information of the network slice that the terminal is allowed to access 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, this process can be referred to... Figure 7 , Figure 9 or Figure 11 As described in [the text].

[0120] S505. The mobility management network element sends the second information to the access network device, and the access network device receives the second information accordingly.

[0121] In one possible design, if the authentication and authorization process of the network slice to be authenticated and authorized is successful, the mobility management network element initiates a UE configuration update process, sending a first message to the access network device including a UE configuration update command and first information. 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. Specifically, this process can be referred to as follows: Figure 6 Or as described in 7.

[0122] In another possible design, if the authentication and authorization processes for the network slice to be authenticated and authorized all fail, and the identifier information of the network slice that the terminal is allowed to access is not empty (e.g., 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, this process can be referred to as follows: Figure 8 or Figure 9 As described in [the text].

[0123] 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].

[0124] 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.

[0125] 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 execution (such as 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, and sends the target NSSAI and the RFSP index corresponding to the target NSSAI 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 execution.

[0126] 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.

[0127] 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: 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.

[0128] 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).

[0129] 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.

[0130] Specifically, the AMF stores the S-NSSAIs supported by each TA. Based on the locally stored S-NSSAIs supported by each TA, the AMF can determine which S-NSSAIs in the requested NSSAIs are included in the terminal's subscription data but are not supported by the TA where the RAN resides. The AMF then treats the S-NSSAIs not supported by the TA where the RAN resides as rejected NSSAIs. In this embodiment, S-NSSAIs not supported by the TA where the RAN resides can also be understood as S-NSSAIs that the terminal is not allowed to access through the TA where the RAN resides, or S-NSSAIs that are unavailable on the TA where the RAN resides, with the reason for rejection being: the current TA does not support them.

[0131] In addition, the AMF can also obtain the UE's subscription data. The UE's subscription data may include the S-NSSAI subscribed to by the UE and indication information regarding whether the S-NSSAI requires NSAA execution. The AMF can determine whether the S-NSSAI contained in the requested NSSAI requires NSAA execution based on the UE's subscription data. S-NSSAIs included in the subscription data within the requested NSSAI that require NSAA execution are placed in the pending NSSAI. S-NSSAIs included in the subscription data within the requested NSSAI that do not require NSAA execution are identified as S-NSSAIs allowed for UE access. These S-NSSAIs allowed for terminal access are placed in the allowed NSSAI. For clarity, in this embodiment, the allowed NSSAI determined by the AMF before the NSAA procedure is referred to as the original allowed NSSAI.

[0132] For example, the UE's subscription data can be pre-stored in the UDM. The AMF can call the UDM's service interface Nudm_subscriber data management_get (Nudm_SDM_Get) to obtain the UE's subscription data. The UDM sends the UE's subscription data to the AMF through the service interface Nudm_SDM_Get response, and then determines the pending NSSAI and the original allowed NSSAI based on the obtained UE subscription data.

[0133] It should be understood that in the embodiments of this application, the S-NSSAI contained in the original allowed NSSAI is different from (or has no overlap with) the S-NSSAI contained in the rejected NSSAI, and the S-NSSAI contained in the original allowed NSSAI is different from (or has no overlap with) the S-NSSAI contained in the pending NSSAI.

[0134] S603 and AMF store the first information in the context of the UE.

[0135] The first piece of information may include rejected NSSAI or requested NSSAI.

[0136] Optionally, the AMF also stores the first indication information in the UE's context. As described in S501, the first indication information can be used to indicate one or more of the following: indicating that the terminal selects a new TA that supports the target NSSAI; or indicating that the UE needs to be redirected to another TA or another frequency band to access the network slice. Alternatively, it can indicate that after the NSSAA procedure is completed, the AMF needs to obtain the target NSSAI and the corresponding RFSP index.

[0137] It should be understood that saving the first instruction information is an optional step; it can be performed or not, and there is no restriction on this step.

[0138] S604. The AMF sends a registration accept message to the UE via the RAN. Correspondingly, the UE receives the registration accept message from the AMF via the RAN.

[0139] The registration acceptance message can carry rejected NSSAI, pending NSSAI, and the original allowed NSSAI.

[0140] Specifically, the AMF can send an N2 message carrying a registration acceptance message to the RAN. The RAN receives the N2 message, obtains the registration acceptance message from the N2 message, and sends the registration acceptance message to the UE.

[0141] S605 and AMF initiate an NSSAA process for each S-NSSAI contained in the pending NSSAI, and obtain the result of the NSSAA process for each S-NSSAI.

[0142] Specifically, the execution process of the NSSAA procedure can be referred to existing technologies and will not be elaborated here.

[0143] S606. If the result of the NSAA process for the S-NSSAI contained in the pending NSSAI is successful authentication and authorization, then the AMF will put the S-NSSAI that successfully executed NSAA in the pending NSSAI and the original allowed NSSAI determined by the AMF in S602 into the new allowed NSSAI. This means that the allowed NSSAI determined after the NSAA process includes not only the allowed NSSAI determined in S603, but also the pending NSSAI that successfully authenticated and authorized.

[0144] For example, suppose the requested NSSAIs include S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and these three S-NSSAIs are included in the UE's subscribed NSSAIs. If the RAN the UE is currently connected to is TA1, and if TA1 supports S-NSSAI-1, then the rejected NSSAIs include S-NSSAI-2 and S-NSSAI-3. Also, according to Table 3 above, S-NSSAI-1 supported by TA1 requires NSSAA execution, so the pending NSSAIs include S-NSSAI-1, and the original allowed NSSAIs are empty. The AMF initiates an NSSAA procedure for S-NSSAI-1. If the authentication and authorization of S-NSSAI-1 is successfully executed, the original allowed NSSAIs are updated, and S-NSSAI-1 is placed into the original allowed NSSAIs to obtain a new allowed NSSAI. The newly determined allowed NSSAI at this time includes S-NSSAI-1.

[0145] For example, suppose the requested NSSAIs include S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and these three S-NSSAIs are included in the NSSAIs subscribed to by the UE. If the RAN currently accessed by the UE is TA3, and if TA3 supports S-NSSAI-2 and S-NSSAI-3, then the rejected NSSAIs include S-NSSAI-1. Furthermore, according to Table 3 above, S-NSSAI-2 supported by TA3 requires NSAA execution, so the pending NSSAIs include S-NSSAI-2. S-NSSAI-3 supported by TA3 does not require NSAA execution, and the original allowed NSSAIs are {S-NSSAI-3}. AMF initiates the NSSAA process for S-NSSAI-2. If the authentication and authorization of S-NSSAI-2 is successfully executed, the original allowed NSSAI is updated, and S-NSSAI-2 is placed into the original allowed NSSAI to obtain a new allowed NSSAI. At this time, the new allowed NSSAI is determined as {S-NSSAI-2, S-NSSAI-3}, which is different from the allowed NSSAI determined in question 1 above.

[0146] S607 and AMF determine the target NSSAI based on the first information and the new allowed NSSAI determined in S606.

[0147] Optionally, if the AMF stores the first information and the first indication information in S603, the AMF can, in response to the first indication information, obtain the first information from the UE's context after the NSAA process of all S-NSSAIs included in the pending NSSAI is completed, determine the target NSSAI based on 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.

[0148] In this application embodiment, the target NSSAI may include some or all of the S-NSSAIs in the rejected NSSAI; or it may include some or all of the S-NSSAIs in the rejected NSSAI and some or all of the S-NSSAIs in the newly allowed NSSAI. For the target NSSAI, there exists a TA in the network that can support all the S-NSSAIs included in the target NSSAI. This TA may be called a common TA. There exists a cell in this common TA (which may be called the target cell in this application). The frequency of this cell corresponds to the network slice (i.e., the target network slice) indicated by all the S-NSSAIs included in the target NSSAI. In this application, the frequency of this cell may be called a common access frequency. The terminal can access the target network slice through the frequency of this cell in the common TA. In this embodiment of the application, the determined target NSSAI satisfies the following condition: all network slices corresponding to the target NSSAI can be supported by a certain public TA. Thus, when the target NSSAI is determined, the network-side device can determine the RFSP index corresponding to the target network slice based on the target NSSAI. The RFSP index corresponds to / indicates a certain access frequency point (i.e., a public access frequency point) in the public TA corresponding to the target network slice. This access frequency point can be used for the terminal to access the target network slice.

[0149] In this embodiment, the process by which the AMF determines the target NSSAI based on the first information and the new allowed NSSAI is as follows. It should be understood that the following description uses the AMF determining the target NSSAI as an example; the process by which other network elements (such as the NSSF) determine the target NSSAI based on the first information and the new allowed NSSAI can refer to the following.

[0150] In one example, the first information includes the requested NSSAI. The AMF determines the target NSSAI based on the first information and the new allowed NSSAI, which can include either of the following two implementation methods: Method 1: The AMF, based on the NSSAIs supported by the current TA, identifies the NSSAIs not supported by the current TA (i.e., rejected NSSAIs) from the requested NSSAIs. The AMF then determines which S-NSSAIs from the newly allowed NSSAIs are included in the target NSSAI based on the S-NSSAIs supported by each TA deployed in the network. Details are as follows: (1) Target NSSAI includes some or all of the S-NSSAI in rejected NSSAI, but does not include the S-NSSAI included in the new allowed NSSAI.

[0151] For example, if a TA exists in the TA list that supports some S-NSSAIs of rejected NSSAIs, but does not support any S-NSSAIs included in allowed NSSAIs, then the target NSSAI contains some S-NSSAIs of rejected NSSAIs. Alternatively, if a TA supports all S-NSSAIs of rejected NSSAIs, but does not support any S-NSSAIs included in allowed NSSAIs, then the target NSSAI contains all S-NSSAIs of rejected NSSAIs.

[0152] For example, if a rejected NSSAI includes K S-NSSAIs, where K is an integer greater than or equal to 1, and these K S-NSSAIs are supported by different TAs (i.e., no common TA simultaneously supports the K S-NSSAIs contained in the rejected NSSAI), and the network slices indicated by the S-NSSAIs contained in the rejected NSSAI are deployed on different TAs, then the AMF can select one S-NSSAI from the rejected NSSAIs as the target NSSAI according to its local policy.

[0153] The local policy may include at least one of the following: selecting the S-NSSAI with the highest priority, or selecting the S-NSSAI with the lowest load. As one implementation, the AMF can obtain the S-NSSAI priority information from the terminal's subscription data or other network elements.

[0154] The above process can be understood as follows: the TA supporting S-NSSAI included in rejected NSSAI is different from the TA supporting S-NSSAI included in allowed NSSAI, and it cannot be guaranteed that the terminal can simultaneously access both rejected and allowed NSSAI through a single TA. However, there exists a TA that allows the terminal to simultaneously access part or all of the S-NSSAI within rejected NSSAI through the cell of that TA. The terminal camped on the cell of that TA can simultaneously request access to part or all of the S-NSSAI within rejected NSSAI through a specific access frequency.

[0155] It should be understood that the embodiments of this application do not limit the deployment location of the TA (which may be referred to as the target TA or new TA in this application) supporting all S-NSSAIs included in the target NSSAI. The deployment location of the TA may overlap with the deployment location of the TA (i.e., the current TA) of the access network device currently accessed by the terminal, or they may not overlap. When the deployment location of the target TA overlaps with the deployment location of the current TA, and the public access frequency point corresponding to the target NSSAI corresponds to a 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.

[0156] (2) Target NSSAI includes some or all of the S-NSSAI in rejected NSSAI, and some or all of the S-NSSAI in newly allowed NSSAI.

[0157] For example, based on the locally stored list of TAs and the network slices supported by each TA, if the AMF determines that there exists a TA in the network that can support some or all of the S-NSSAIs of rejected NSSAIs, and that the TA can also support some or all of the S-NSSAIs contained in allowed NSSAIs, then the target NSSAI can simultaneously contain some or all of the S-NSSAIs of rejected NSSAIs, as well as some or all of the S-NSSAIs of allowed NSSAIs.

[0158] The above process can be understood as follows: A Terminal Access Target (TA) exists in the network. A terminal can simultaneously access a portion or all of the rejected NSSAI (S-NSSAI), as well as a portion or all of the allowed NSSAI, through the cell of that TA. If the terminal is camped on the cell of that TA, it can simultaneously request access to a portion or all of the rejected NSSAI, as well as a portion or all of the allowed NSSAI, through a specific frequency point.

[0159] It should be understood that the term "including" in the embodiments of this application can be understood as "comprising" or "carrying". These words have the same meaning and can be used interchangeably without limitation.

[0160] (3) Determine which S-NSSAIs are included in the target NSSAI based on the S-NSSAI associated with the terminal's session.

[0161] For example, if a terminal currently has an established session (such as a protocol data unit (PDU) session), and the S-NSSAI associated with this session is included in the allowed NSSAI, to ensure the service continuity of the terminal's session, the AMF can determine whether a TA exists that supports the S-NSSAI associated with the terminal's session in the allowed NSSAI. If it exists, it determines whether the TA also supports some or all of the S-NSSAI in the rejected NSSAI. If the TA also supports some or all of the S-NSSAI in the rejected NSSAI, it means that the terminal can simultaneously access some or all of the S-NSSAI in the rejected NSSAI and the S-NSSAI associated with the terminal's session in the allowed NSSAI through the cells in the TA. Then, the target NSSAI can include some or all of the S-NSSAI in the rejected NSSAI and the S-NSSAI associated with the terminal's session in the allowed NSSAI. Optionally, the terminal can also access the allowed NSSAI through the cells in the TA. Other S-NSSAIs supported by this TA in the NSSAI. Correspondingly, the target NSSAI can also include other S-NSSAIs supported by this TA in the allowed NSSAI.

[0162] Method 2: The first piece of information includes requested NSSAI, and AMF will identify requested NSSAI as targetNSSAI.

[0163] For example, based on the locally stored list of TAs and the network slices supported by each TA, the AMF determines that there exists a TA that can support all S-NSSAIs included in the requested NSSAI. In this case, the AMF can directly identify the requested NSSAI as the target NSSAI.

[0164] In another example, the first information includes the rejected NSSAI. The AMF determines the target NSSAI based on the first information and the new allowed NSSAI. This can include the AMF determining the target NSSAI based on the rejected NSSAI and the new allowed NSSAI. Specifically, this process can be referred to in Method 1 above and will not be repeated here.

[0165] It should be understood that, in addition to the methods described above, mobility management network elements may also determine which S-NSSAIs are specifically included in targetNSSAI through other methods, and this application does not impose any restrictions.

[0166] For example, assuming the new allowed NSSAI includes {S-NSSAI-1, S-NSSAI-2} and 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, and TA2 and TA3 support S-NSSAI-2. TA2 supports both S-NSSAI-3 and S-NSSAI-1 and S-NSSAI-2. The access frequency point 1 of the cell in TA2 can fully cover / support UE access to the network slices corresponding to S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3. Then the target NSSAI is determined to be {S-NSSAI-1, S-NSSAI-2, S-NSSAI-3}.

[0167] S608, AMF sends target NSSAI to PCF. Correspondingly, PCF receives target NSSAI from AMF.

[0168] For example, AMF can call the PCF's service-oriented operation: the service interface Npcf_AMPolicyControl_Update request, which sends the target NSSAI to PCF along with the Npcf_AMPolicyControl_Update request.

[0169] Optionally, the AMF may also send the UE's identification information and other information to the PCF, without restriction.

[0170] S609, PCF determines the RFSP index corresponding to the target NSSAI based on the target NSSAI, and sends the RFSP index corresponding to the target NSSAI to AMF. Correspondingly, AMF receives the RFSP index corresponding to the target NSSAI from PCF.

[0171] Specifically, PCF locally configures the correspondence between S-NSSAI and RFSP indexes. PCF determines the RFSP index corresponding to the target NSSAI based on the correspondence between the target NSSAI and S-NSSAI and RFSP indexes.

[0172] For example, PCF calls its own service-oriented operation: the service-oriented interface Npcf_AMPolicyControl_Update response, which sends the RFSP index corresponding to the target NSSAI to AMF in the Npcf_AMPolicyControl_Update response.

[0173] Since the pending NSSAI contains an S-NSSAI that successfully executed NSSAA, the allowed NSSAI is updated. Therefore, the AMF needs to send the new allowed NSSAI to the UE through the UE configuration update procedure. During the UE configuration update procedure, the target NSSAI and its corresponding RFSP index can be sent to the RAN to reduce signaling overhead. Specifically, this process is described in S610 and S611.

[0174] Optionally, after the AMF determines the target NSSAI and its corresponding RFSP index, the AMF can delete the first information stored in the UE's context. Furthermore, if the AMF also stores first indication information in S603, the AMF can also delete the first indication information after determining the target NSSAI and its corresponding RFSP index.

[0175] S610 and AMF send a first message to RAN, which carries a UE configuration update command and second information {target NSSAI, RFSP index corresponding to target NSSAI}. Correspondingly, RAN receives the first message from AMF.

[0176] The first message can be an N2 message. The UE configuration update command can carry the new allowed NSSAI. The UE configuration update command can be used to instruct the updating of relevant UE configurations, such as updating the UE's allowed NSSAI.

[0177] S611, the RAN sends a UE configuration update command to the UE. Correspondingly, the UE receives the UE configuration update command.

[0178] S612, the RAN determines the access frequency information corresponding to the target NSSAI based on the target NSSAI and its corresponding RFSP index, and sends this information to the UE. Correspondingly, the UE receives the access frequency information corresponding to the target NSSAI.

[0179] In one implementation, the access frequency information corresponding to the target NSSAI can be used to indicate the access frequency corresponding to the target NSSAI, and can be used by the UE to select a target cell that supports access to all network slices corresponding to the target NSSAI. Specifically, the access frequency information corresponding to the target NSSAI can be an index of the access frequency corresponding to the target NSSAI, through which the UE can access all network slices corresponding to the target NSSAI. For example, if the access frequency corresponding to the target NSSAI is F1, then the access frequency information corresponding to the target NSSAI includes F1.

[0180] Specifically, the RAN locally configures the correspondence between the subscriber profile ID for RAT / frequency selection priority (SPID) and the frequency band priority list information, or the correspondence between the RFSP index and the frequency band priority list information. This correspondence can be shown in Table 4. The RAN can determine the frequency band priority list information corresponding to the RFSP index of the target NSSAI based on the RFSP index carried in the first message and this correspondence, and select the access frequency point corresponding to the target NSSAI from the determined frequency band priority list information.

[0181] Table 4

[0182] It should be understood that the frequency band priority list information in this application can also be referred to as frequency band information, frequency band list, frequency band priority information, frequency priority list, frequency information, frequency list, frequency priority information, frequency priority list, frequency point information, frequency point list, frequency point priority information, or frequency point priority list. It should be noted that in this application, the SPID referred to on the radio side and the RFSP index on the core network side are the same concept; for consistency, it is referred to as RFSP index on both the core network side and the radio side.

[0183] It should be understood that the access frequency point described in the embodiments of this application can also be understood as a frequency band or access frequency band, without limitation.

[0184] For example, the RAN can send the access frequency point corresponding to the target NSSAI to the UE through the access network release (AN release) procedure. For instance, the RAN can send a radio resource control (RRC) release message to the UE. This RRC release message can be used to instruct the UE to release the connection with the current cell and select a new cell. The RRC release message can carry the access frequency point corresponding to the target NSSAI.

[0185] S613. The UE selects a target cell based on the access frequency information corresponding to the target NSSAI and initiates a registration update procedure to that target cell. For example, according to S612, after the UE receives the access frequency information corresponding to the target NSSAI from the RAN, the UE selects a cell that supports that access frequency and camps there. It then sends a registration request message carrying the requested NSSAI to the AMF through that cell. Here, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0186] It should be understood that, in addition to the requested NSSAI, the registration request message may also include other information, such as the UE's identification information.

[0187] S614 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.

[0188] Specifically, the process can be referred to existing technologies, and will not be elaborated here.

[0189] based on Figure 6The method described above, in a scenario where the AMF determines that the TA currently in which the RAN resides does not support the S-NSSAI in the requested NSSAI, and the AMF also determines that the requested NSSAI includes S-NSSAIs that require NSAA execution (such as pending NSSAIs), after all S-NSSAIs included in the pending NSSAI have completed the NSAA process and the NSAA execution of the S-NSSAIs is successful, the AMF determines the target NSSAI based on the new allowed NSSAI and the first information (requested NSSAI or rejected NSSAI), and obtains the RFSP index corresponding to the target NSSAI from the PCF. The AMF then sends the target NSSAI and the RFSP index corresponding to the target NSSAI to the RAN, triggering the RAN to instruct the UE to select a new TA. This new TA can support all network slices corresponding to the target NSSAI, ensuring that the UE can successfully access the network slice in scenarios where the requested NSSAI includes both S-NSSAIs that the current TA does not support and S-NSSAIs that require NSAA execution.

[0190] The above Figure 6 In this method, the AMF determines the target NSSAI and interacts with the PCF to obtain the RSFP index corresponding to the target NSSAI. Alternatively, other network elements can determine the target NSSAI, interact with the PCF to obtain the RSFP index corresponding to the target NSSAI, and send the target NSSAI and its corresponding RSFP index to the AMF. Specifically, this method can be referred to below. Figure 7 As described in [the text]. Figure 7 The execution process of S701-S706 and Figure 6 The execution process of S601-S606 is the same, and the execution process of S709-S715 is the same. Figure 6 The execution process of S608-S614 is the same, while S707-S708 can be used as a replacement for S607.

[0191] Figure 7 Another method for selecting a tracking region provided in the embodiments of this application, such as Figure 7 As shown, it may include: S701. 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.

[0192] Specifically, the description of the registration request message and the execution process of S701 are the same as those of S601, and will not be repeated here.

[0193] S702, 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.

[0194] Specifically, S702 is the same as S602, so I will not go into details.

[0195] S703 and AMF store the first information in the context of the UE.

[0196] Optionally, the AMF also stores the first indication information in the context of the UE.

[0197] Specifically, the description of the first instruction information and the execution process of S703 are the same as those of S603, and will not be repeated here.

[0198] S704, the AMF sends a registration accept message to the UE via the RAN. Correspondingly, the UE receives the registration accept message from the AMF via the RAN.

[0199] Specifically, S704 is the same as S604, so I will not go into details.

[0200] S705 and AMF initiate an NSSAA process for each S-NSSAI contained in the pending NSSAI, and obtain the result of the NSSAA process for each S-NSSAI.

[0201] Specifically, the execution process of the NSSAA procedure can be referred to existing technologies and will not be elaborated here.

[0202] S706. If the result of the NSAA process for the S-NSSAI contained in the pending NSSAI is successful authentication and authorization, then the AMF will put the S-NSSAI that successfully executed NSAA in the pending NSSAI and the original allowed NSSAI determined by the AMF in S702 into the new allowed NSSAI. This means that the allowed NSSAI determined after the NSAA process includes not only the allowed NSSAI determined in S703 (i.e. the original allowed NSSAI), but also the S-NSSAI that successfully authenticated and authorized in the pending NSSAI.

[0203] Specifically, S706 is the same as S606, so I will not go into details.

[0204] S707 and AMF send the first message and the new allowed NSSAI determined in S706 to NSSF. Correspondingly, NSSF receives the first message and the new allowed NSSAI determined in S706, and NSSF determines the target NSSAI based on the first message and the new allowed NSSAI determined in S706.

[0205] Specifically, the AMF can invoke the NSSF's service-oriented operation: the service interface Nnssf_Network Slice Selection Get (Nnssf_NSSelection_Get) sends the first information and the new allowed NSSAI determined in S706 to the NSSF. Optionally, the AMF also sends an instruction to the NSSF instructing the NSSF to determine the target NSSAI, so that the NSSF responds to the instruction and determines the target NSSAI based on the first information and the new allowed NSSAI determined in S706.

[0206] It should be understood that if the AMF stores the first information and the first indication information in S703, then the AMF can, in response to the first indication information, obtain the first information from the context of the UE and send the first information and the new allowed NSSAI determined in S706 to the NSSF after the NSSAA procedure of all S-NSSAIs included in the pending NSSAI is completed.

[0207] The process by which NSSF determines the target NSSAI is the same as that by AMF, and will not be described in detail here.

[0208] The S708 and NSSF send the target NSSAI to the AMF. Correspondingly, the AMF receives the target NSSAI.

[0209] Specifically, NSSF calls NSSF's service-oriented operation: the service interface Nnssf_NSSelection_Get response returns the target NSSAI to AMF.

[0210] S709: The AMF sends the target NSSAI to the PCF. Correspondingly, the PCF receives the target NSSAI from the AMF.

[0211] Specifically, S709 is the same as S608, so I will not go into details.

[0212] S710 and PCF determine the RFSP index corresponding to the target NSSAI based on the target NSSAI, and send the RFSP index corresponding to the target NSSAI to AMF. Correspondingly, AMF receives the RFSP index corresponding to the target NSSAI from PCF.

[0213] Specifically, S710 is the same as S609, so I will not go into details.

[0214] Optionally, after obtaining the target NSSAI and its corresponding RFSP index, the AMF can delete the first information stored in the UE's context. Furthermore, if the AMF also stores first indication information in S703, it can also delete the first indication information after obtaining the target NSSAI and its corresponding RFSP index.

[0215] Since the pending NSSAI contains an S-NSSAI that successfully executed NSSAA, the allowed NSSAI is updated. Therefore, the AMF needs to send the new allowed NSSAI to the UE through the UE configuration update procedure. During the UE configuration update procedure, the target NSSAI and its corresponding RFSP index can be sent to the RAN to reduce signaling overhead. Specifically, this process is described in S711 and S712.

[0216] S711, the AMF sends a first message to the RAN, which carries a UE configuration update command and second information {target NSSAI, the RFSP index corresponding to the target NSSAI}. Correspondingly, the RAN receives the first message from the AMF.

[0217] Specifically, S711 is the same as S610, so I will not go into details.

[0218] S712, RAN sends a UE configuration update command to UE. Correspondingly, UE receives the UE configuration update command.

[0219] S713, the RAN determines the access frequency information corresponding to the target NSSAI based on the target NSSAI and the corresponding RFSP index, and sends the access frequency information corresponding to the target NSSAI to the UE. Correspondingly, the UE receives the access frequency information corresponding to the target NSSAI.

[0220] Specifically, S713 is the same as S612, so I will not go into details.

[0221] S714. The UE selects a target cell based on the access frequency information corresponding to the target NSSAI and initiates a registration update procedure to that target cell. For example, according to S713, after the UE receives the access frequency information corresponding to the target NSSAI from the RAN, the UE selects a cell that supports that access frequency and camps there. It then sends a registration request message carrying the requested NSSAI to the AMF through that cell. Here, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0222] It should be understood that, in addition to the requested NSSAI, the registration request message may also include other information, such as the UE's identification information.

[0223] Based on the received registration request message, S715 and AMF trigger other network elements to complete other processes of the registration process, enabling the UE to access the network slice corresponding to the target NSSAI at the current location.

[0224] Specifically, the process can be referred to existing technologies, and will not be elaborated here.

[0225] based on Figure 7 The method described above, in a scenario where the AMF determines that the TA currently in which the RAN resides does not support the S-NSSAI in the requested NSSAI, and the AMF also determines that the requested NSSAI includes S-NSSAIs that require NSAA execution (such as pending NSSAIs), after all S-NSSAIs included in the pending NSSAI have completed the NSAA process and the NSAA execution of the S-NSSAIs is successful, the AMF obtains the target NSSAI from the NSSF and the corresponding RFSP index from the PCF based on the new allowed NSSAI and the first information (requested NSSAI or rejected NSSAI), and sends the target NSSAI and the corresponding RFSP index to the RAN, triggering the RAN to instruct the UE to select a new TA. This new TA can support all network slices corresponding to the target NSSAI, ensuring that the UE can successfully access the network slice in scenarios where the requested NSSAI includes both S-NSSAIs that the current TA does not support and S-NSSAIs that require NSAA execution.

[0226] The above Figure 6 or Figure 7 The method shown addresses a scenario where the current RAN's TA does not support S-NSSAIs in the requested NSSAI, but the requested NSSAI includes S-NSSAIs requiring NSAA execution (e.g., pending NSSAIs). Taking the successful execution of NSAA for the S-NSSAIs included in the pending NSSAI as an example, the method for selecting the tracking region is described below. The following describes the scenario where NSAA execution fails for all S-NSSAIs included in the pending NSSAI.

[0227] Figure 8 Another method for selecting a tracking region provided in the embodiments of this application, such as Figure 8 As shown, it may include: S801. 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.

[0228] Specifically, the description of the registration request message and the execution process of S801 are the same as those of S601, and will not be repeated here.

[0229] S802, 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.

[0230] Specifically, S802 is the same as S602, so I will not go into details.

[0231] S803 and AMF store the first information in the context of the UE.

[0232] Optionally, the AMF also stores the first indication information in the context of the UE.

[0233] Specifically, the description of the first instruction information and the execution process of S803 are the same as those of S603, and will not be repeated here.

[0234] S804, the AMF sends a registration accept message to the UE via the RAN. Correspondingly, the UE receives the registration accept message from the AMF via the RAN.

[0235] Specifically, S804 is the same as S604, so I will not go into details.

[0236] S805 and AMF initiate an NSSAA process for each S-NSSAI contained in the pending NSSAI, and obtain the result of the NSSAA process for each S-NSSAI.

[0237] Specifically, the execution process of the NSSAA procedure can be referred to existing technologies and will not be elaborated here.

[0238] S806. If the result of the NSAA process for all S-NSSAIs included in the pending NSSAI is authentication and authorization failure, then the AMF will not update the original allowed NSSAI determined by the AMF in S802. This means that the allowed NSSAI determined after the NSAA process 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.

[0239] Specifically, S806 is the same as S606, so I will not go into details.

[0240] It should be noted that, Figure 8 In the embodiment shown, the original allowed NSSAI is not empty, that is, the original allowed NSSAI includes at least one S-NSSAI.

[0241] For example, suppose the requested NSSAIs include S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and these three S-NSSAIs are included in the UE's subscribed NSSAIs. If the RAN the UE is currently connected to is TA3, and if TA3 supports S-NSSAI-2 and S-NSSAI-3, then the rejected NSSAIs include S-NSSAI-1. According to Table 3 above, S-NSSAI-2 supported by TA3 requires NSAA execution, so the pending NSSAIs include S-NSSAI-2. S-NSSAI-3 supported by TA3 does not require NSAA execution, and the original allowed NSSAI is {S-NSSAI-3}. The AMF initiates an NSAA procedure for S-NSSAI-2. If the NSAA for S-NSSAI-2 fails, the original allowed NSSAI is not updated. The newly determined allowed NSSAI is {S-NSSAI-3}, which is the same as the original allowed NSSAI.

[0242] S807 and AMF determine the target NSSAI based on the first information and the new allowed NSSAI determined in S806.

[0243] Specifically, the description of S807 can be found in S607. It should be understood that since the NSSAA process for the pending NSSAI failed in S806, the new allowed NSSAI and the original allowed NSSAI, i.e., the allowed NSSAI determined before the NSSAA process was not updated, can be understood in S807 as determining the target NSSAI based on the first information and the original allowed NSSAI, which will not be elaborated further.

[0244] It should be understood that if the AMF stores the first information and the first indication information in S803, the AMF can, in response to the first indication information, obtain the first information from the context of the UE after the NSSAA process of all S-NSSAIs included in the pending NSSAI is completed, and determine the target NSSAI based on the first information and the original allowed NSSAI.

[0245] S808 and AMF send target NSSAI to PCF. Correspondingly, PCF receives target NSSAI from AMF.

[0246] Specifically, S808 is the same as S608, so I will not go into details.

[0247] S809 and PCF determine the RFSP index corresponding to the target NSSAI based on the target NSSAI, and send the RFSP index corresponding to the target NSSAI to AMF. Correspondingly, AMF receives the RFSP index corresponding to the target NSSAI from PCF.

[0248] Specifically, S809 is the same as S609, so I will not go into details.

[0249] 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 UE's context. Furthermore, if the AMF also stores first indication information in S703, the AMF can also delete the first indication information after determining the target NSSAI and obtaining the RFSP index corresponding to the target NSSAI.

[0250] Since all S-NSSAIs in the pending NSSAI have failed NSAA, the allowed NSSAI remains unchanged and is the original allowed NSSAI. Because the original allowed NSSAI was already included in the registration acceptance message sent to the UE, the AMF does not need to send a new allowed NSSAI to the UE through the UE configuration update procedure. Instead, it initiates a UE context update request to update the UE's access frequency. Specifically, this process is as described in S810.

[0251] S810: The AMF sends a UE context modification request to the RAN. The UE context modification request carries the second piece of information: {target NSSAI, RFSP index corresponding to the target NSSAI}. Correspondingly, the RAN receives the UE context modification request from the AMF.

[0252] The UE context update request can be used to request an update to the UE's context stored on the RAN, such as updating the UE's access frequency in the UE's context. In addition to carrying the second information, the UE context update request can also carry other information, such as the UE's identification information, without restriction.

[0253] S811, the RAN determines the access frequency information corresponding to the target NSSAI based on the target NSSAI and the corresponding RFSP index, and sends the access frequency information corresponding to the target NSSAI to the UE. Correspondingly, the UE receives the access frequency information corresponding to the target NSSAI.

[0254] Specifically, S811 is the same as S612, so I will not go into details.

[0255] S812: The UE selects a target cell based on the access frequency information corresponding to the target NSSAI and initiates a registration update procedure to that target cell. For example, according to S811, after the UE receives the access frequency information corresponding to the target NSSAI from the RAN, the UE selects a cell that supports that access frequency and camps there. It then sends a registration request message carrying the requested NSSAI to the AMF through that cell. In this case, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0256] It should be understood that, in addition to the requested NSSAI, the registration request message may also include other information, such as the UE's identification information.

[0257] 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.

[0258] Specifically, the process can be referred to existing technologies, and will not be elaborated here.

[0259] 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 (such as pending NSSAI), if all S-NSSAIs included in the pending NSSAI fail NSSAA execution, the original allowed NSSAI is not updated. The resulting new allowed NSSAI is the same as the original allowed NSSAI. Then, based on the new allowed NSSAI (which can be understood as the original allowed NSSAI) and the first 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 / new 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.

[0260] 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].

[0261] Figure 9Another method for selecting a tracking region provided in the embodiments of this application, such as Figure 9 As shown, it may include: S901, 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.

[0262] Specifically, the description of the registration request message and the execution process of S901 are the same as those of S601, and will not be repeated here.

[0263] S902, 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.

[0264] Specifically, S902 is the same as S602, so I will not go into details.

[0265] S903 and AMF store the first information in the context of the UE.

[0266] Optionally, the AMF also stores the first indication information in the context of the UE.

[0267] Specifically, the description of the first instruction information and the execution process of S903 are the same as those of S603, and will not be repeated here.

[0268] S904. The AMF sends a registration accept message to the UE via the RAN. Correspondingly, the UE receives the registration accept message from the AMF via the RAN.

[0269] Specifically, S904 is the same as S604, so I will not go into details.

[0270] S905 and AMF initiate an NSSAA process for each S-NSSAI contained in the pending NSSAI, and obtain the result of the NSSAA process for each S-NSSAI.

[0271] Specifically, the execution process of the NSSAA procedure can be referred to existing technologies and will not be elaborated here.

[0272] S906. If the result of the NSAA process for all S-NSSAIs included in the pending NSSAI is authentication and authorization failure, then the AMF will not update the original allowed NSSAI determined by the AMF in S902. This means that the allowed NSSAI determined after the NSAA process 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.

[0273] Specifically, S906 is the same as S806, so I will not go into details.

[0274] It should be noted that, Figure 9 In the embodiment shown, the original allowed NSSAI is not empty, that is, the original allowed NSSAI includes at least one S-NSSAI.

[0275] S907 and AMF send the first message and the new allowed NSSAI to NSSF. Correspondingly, NSSF receives the first message and the original allowed NSSAI, and determines the target NSSAI based on the first message and the new allowed NSSAI.

[0276] It should be understood that, since the NSSAA process for pending NSSAI in S906 failed, the new allowed NSSAI in S907 can be understood as the original allowed NSSAI, i.e., the allowed NSSAI determined before the NSSAA process was not updated.

[0277] Specifically, the AMF can invoke the NSSF's service-oriented operation: the service interface Nnssf_NSSelection_Get sends the first information and the original allowed NSSAI to the NSSF. Optionally, the AMF also sends an instruction to the NSSF instructing the NSSF to determine the target NSSAI, so that the NSSF responds to the instruction and determines the target NSSAI based on the first information and the original allowed NSSAI.

[0278] It should be understood that if the AMF stores the first information and the first indication information in S903, then the AMF can, in response to the first indication information, obtain the first information from the context of the UE and send the first information and the new allowed NSSAI determined in S906 to the NSSF after the NSSAA procedure of all S-NSSAIs included in the pending NSSAI is completed.

[0279] The process by which NSSF determines the target NSSAI is the same as that by AMF, and will not be described in detail here.

[0280] The S908 and NSSF send the target NSSAI to the AMF. Correspondingly, the AMF receives the target NSSAI.

[0281] Specifically, NSSF calls NSSF's service-oriented operation: the service interface Nnssf_NSSelection_Get response returns the target NSSAI to AMF.

[0282] S909 and AMF send target NSSAI to PCF. Correspondingly, PCF receives target NSSAI from AMF.

[0283] Specifically, S909 is the same as S608, so I will not go into details.

[0284] S910 and PCF determine the RFSP index corresponding to the target NSSAI based on the target NSSAI, and send the RFSP index corresponding to the target NSSAI to AMF. Correspondingly, AMF receives the RFSP index corresponding to the target NSSAI from PCF.

[0285] Specifically, S910 is the same as S609, so I will not go into details.

[0286] Optionally, after obtaining the target NSSAI and its corresponding RFSP index, the AMF can delete the first information stored in the UE's context. Furthermore, if the AMF also stores first indication information in S903, it can also delete the first indication information after obtaining the target NSSAI and its corresponding RFSP index.

[0287] Since all S-NSSAIs in the pending NSSAI have failed NSAA, the allowed NSSAI remains unchanged and is the original allowed NSSAI. Because the original allowed NSSAI was already included in the registration acceptance message sent to the UE, the AMF does not need to send a new allowed NSSAI to the UE through the UE configuration update procedure. Instead, it initiates a UE context update request to update the UE's access frequency. Specifically, this process is as described in S911.

[0288] S911, the AMF sends a UE context modification request to the RAN, which carries the second piece of information: {target NSSAI, RFSP index corresponding to the target NSSAI}. Correspondingly, the RAN receives the UE context modification request from the AMF.

[0289] Specifically, the S911 is the same as the S810, so I will not go into details.

[0290] S912, the RAN determines the access frequency information corresponding to the target NSSAI based on the target NSSAI and its corresponding RFSP index, and sends this information to the UE. Correspondingly, the UE receives the access frequency information corresponding to the target NSSAI.

[0291] Specifically, S912 is the same as S612, so I will not go into details.

[0292] S913. The UE selects a target cell based on the access frequency information corresponding to the target NSSAI and initiates a registration update procedure to that target cell. For example, according to S912, after the UE receives the access frequency information corresponding to the target NSSAI from the RAN, the UE selects a cell that supports that access frequency and camps there. It then sends a registration request message carrying the requested NSSAI to the AMF through that cell. Here, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0293] It should be understood that, in addition to the requested NSSAI, the registration request message may also include other information, such as the UE's identification information.

[0294] S914 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.

[0295] Specifically, the process can be referred to existing technologies, and will not be elaborated here.

[0296] based on Figure 9The method described above, in a scenario where the AMF determines that the TA currently hosting 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 NSAA execution (such as pending NSSAIs), after all S-NSSAIs included in the pending NSSAI have completed the NSAA process, and the NSAA of the S-NSSAI fails, does not update the original allowed NSSAI. The resulting new allowed NSSAI is the same as the original allowed NSSAI. Based on the new allowed NSSAI (which can be understood as the original allowed NSSAI) and the first information (requested NSSAI or rejected NSSAI), the AMF obtains the target NSSAI from the NSSF and the RFSP index corresponding to the target NSSAI from the PCF, and sends the target NSSAI and the corresponding RFSP index to the RAN, triggering the RAN to instruct the UE to select a new TA. This new TA 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.

[0297] The above Figure 8 or Figure 9 The method described herein, considering a scenario where the current RAN's TA does not support S-NSSAIs in the requested NSSAI, but the requested NSSAI includes S-NSSAIs requiring NSSAA execution (such as pending NSSAIs), takes the example of all S-NSSAIs included in the pending NSSAI failing NSSAA execution and the original allowed NSSAI not being empty, to illustrate the TA selection method provided in this application embodiment. The following describes the method for selecting the tracking region when all S-NSSAIs included in the pending NSSAI fail NSSAA execution and the original allowed NSSAI is empty: Figure 10 This application provides another method for selecting a tracking region, in which the AMF determines the target NSSAI itself, such as... Figure 10 As shown, it may include: S1001, 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.

[0298] Specifically, the description of the registration request message and the execution process of S1001 are the same as those of S601, and will not be repeated here.

[0299] S1002, AMF determines the S-NSSAIs that the TA containing the RAN in the requested NSSAI does not support, and determines the S-NSSAIs in the requested NSSAIs that require NSSAA execution. It should be noted that... Figure 10 In the example shown, the original allowed NSSAI is empty, meaning that the original allowed NSSAI does not contain S-NSSAI.

[0300] Specifically, the execution process of S1002 is the same as that of S602, and will not be described in detail.

[0301] For example, suppose the requested NSSAIs include S-NSSAI-1, S-NSSAI-2, and S-NSSAI-3, and these three S-NSSAIs are included in the NSSAIs subscribed to by the UE. If the RAN currently accessed by the UE is TA1, and if TA1 supports S-NSSAI-1, then the rejected NSSAIs include S-NSSAI-2 and S-NSSAI-3. According to Table 3, S-NSSAI-1 supported by TA1 requires NSSAA execution, pending NSSAIs include S-NSSAI-1, and the original allowed NSSAIs are empty.

[0302] S1003, AMF stores the first information in the context of the UE.

[0303] Optionally, the AMF also stores the first indication information in the context of the UE.

[0304] Specifically, the description of the first instruction information and the execution process of S1003 are the same as those of S603, and will not be repeated here.

[0305] S1004, the AMF sends a registration accept message to the UE via the RAN. Correspondingly, the UE receives the registration accept message from the AMF via the RAN.

[0306] Specifically, S1004 is the same as S604, and will not be elaborated upon. It should be understood that... Figure 10 In the illustrated embodiment, the original allowed NSSAI included in the registration acceptance message is empty (or called empty allowed NSSAI). The registration acceptance message may or may not carry the original allowed NSSAI.

[0307] S1005 and AMF initiate an NSSAA process for each S-NSSAI contained in the pending NSSAI, and obtain the result of the NSSAA process for each S-NSSAI.

[0308] Specifically, the execution process of the NSSAA procedure can be referred to existing technologies and will not be elaborated here.

[0309] S1006. If the NSAA process results of all S-NSSAIs included in the pending NSSAI fail to authenticate and authorize, the AMF will not update the original allowed NSSAI determined by the AMF in S1002. This means that the allowed NSSAI determined after the NSAA process (which can be called the new allowed NSSAI) is empty, and there is no identification information for the network slice that the terminal is allowed to access.

[0310] Specifically, S1006 is the same as S606, so I will not go into details.

[0311] For example, following the example in S1002, if the AMF initiates an NSSAA procedure for S-NSSAI-1, and the NSSAA procedure for S-NSSAI-1 fails, the original allowed NSSAI will not be updated, and the new allowed NSSAI determined after the NSSAA procedure will still be empty.

[0312] S1007 and AMF determine the target NSSAI based on the first information and the new allowed NSSAI determined in S1006.

[0313] It should be understood that if the AMF stores the first information and the first indication information in S1003, the AMF can, in response to the first indication information, obtain the first information from the context of the UE and determine the target NSSAI based on the first information after the NSSAA process of all S-NSSAIs included in the pending NSSAI is completed.

[0314] Specifically, S1007 can be referenced from S607. Since the NSAA process for pending NSSAI failed in S1006, the new allowed NSSAI is empty. S1007 can be understood as determining the target NSSAI based on the first piece of information.

[0315] S1008, AMF sends target NSSAI to PCF. Correspondingly, PCF receives target NSSAI from AMF.

[0316] Specifically, S1008 is the same as S608, so I will not go into details.

[0317] S1009, PCF determines the RFSP index corresponding to the target NSSAI based on the target NSSAI and sends the RFSP index to AMF. Correspondingly, AMF receives the RFSP index corresponding to the target NSSAI from PCF.

[0318] Specifically, S1009 is the same as S609, so I will not go into details.

[0319] 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 UE's context. Furthermore, if the AMF still stores first indication information in S1003, the AMF can also delete the first indication information after determining the target NSSAI and obtaining the RFSP index corresponding to the target NSSAI.

[0320] Since all S-NSSAIs in the pending NSSAI failed their NSAA registrations, the allowed NSSAI remained empty and was not updated. This registration failure triggered the AMF to initiate a deregistration process. Simultaneously, the UE's context on the RAN was released. During the context release process, the UE was informed of the access frequency corresponding to the target network slice, enabling the UE to access the target network slice through a new TA / cell. Specifically, this process is described in S1010 and S1011.

[0321] S1010, 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 / cancel the current network registration.

[0322] S1011, the AMF sends a UE context release request to the RAN, which carries the second piece of information: {target NSSAI, RFSP index corresponding to the target NSSAI}. Correspondingly, the RAN receives the UE context release request from the AMF.

[0323] The UE context release request can be used to request the release of the UE's context stored on the RAN. In addition to carrying the second information, the UE context release request can also carry the UE's identification information and other information, without restriction.

[0324] S1012, the RAN determines the access frequency information corresponding to the target NSSAI based on the target NSSAI and its corresponding RFSP index, and sends this information to the UE. Correspondingly, the UE receives the access frequency information corresponding to the target NSSAI.

[0325] Specifically, S1011 is the same as S612, and will not be described in detail.

[0326] S1013. The UE selects a target cell based on the access frequency information corresponding to the target NSSAI and initiates a registration update procedure to that target cell. For example, according to S1012, after the UE receives the access frequency information corresponding to the target NSSAI from the RAN, the UE selects a cell that supports that access frequency and camps there. The UE then sends a registration request message carrying the requested NSSAI to the AMF through that cell. In this case, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0327] It should be understood that, in addition to the requested NSSAI, the registration request message may also include other information, such as the UE's identification information.

[0328] S1014, AMF triggers 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.

[0329] Specifically, the process can be referred to existing technologies, and will not be elaborated here.

[0330] based on Figure 10The method described above, in a scenario where the AMF determines that the TA currently in which the RAN resides does not support the S-NSSAI in the requested NSSAI, and the AMF also determines that the requested NSSAI includes S-NSSAIs that require NSAA execution (such as pending NSSAI), if all NSAA executions of the pending NSSAI fail and allowed NSSAI is empty, the AMF initiates a deregistration process. Simultaneously, based on the first information (requested NSSAI or rejected NSSAI) and the empty allowed NSSAI, the AMF determines the target NSSAI and obtains the RFSP index corresponding to the target NSSAI 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 supports all network slices corresponding to the target NSSAI, ensuring that the UE can successfully access the network slice in scenarios where the requested NSSAI includes both S-NSSAIs not supported by the current TA and S-NSSAIs requiring NSAA execution.

[0331] The above Figure 10 The method describes the process by which the AMF determines the target NSSAI and interacts with the PCF to obtain the RSFP index corresponding to the target NSSAI when all S-NSSAIs included in the pending NSSAI fail NSSAA and the allowed NSSAI is empty. Alternatively, other network elements can determine the target NSSAI, interact with the PCF to obtain the RSFP index corresponding to the target NSSAI, and send the target NSSAI and its corresponding RSFP index to the AMF. Specifically, this method can be referred to as follows: Figure 11 As described in [the text].

[0332] Figure 11 This application provides another method for selecting a tracking region, in which the target NSSAI is determined by the NSSF, such as... Figure 11 As shown, it may include: S1101, 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.

[0333] Specifically, the description of the registration request message and the execution process of S1101 are the same as those of S601, and will not be repeated here.

[0334] S1102, AMF determines the S-NSSAIs that the TA containing the RAN in the requested NSSAI does not support, and determines the S-NSSAIs in the requested NSSAIs that require NSSAA execution. It should be noted that... Figure 11 In the example shown, the original allowed NSSAI is empty, meaning that the original allowed NSSAI does not contain S-NSSAI.

[0335] Specifically, the execution process of S1102 is the same as that of S1002, and will not be described in detail.

[0336] S1103, AMF stores the first information in the context of the UE.

[0337] Optionally, the AMF also stores the first indication information in the context of the UE.

[0338] Specifically, the description of the first instruction information and the execution process of S1103 are the same as those of S603, and will not be repeated here.

[0339] S1104. The AMF sends a registration accept message to the UE via the RAN. Correspondingly, the UE receives the registration accept message from the AMF via the RAN.

[0340] Specifically, S1104 is the same as S604, and will not be elaborated upon. It should be understood that... Figure 11 In the illustrated embodiment, the original allowed NSSAI included in the registration acceptance message is empty (or called empty allowed NSSAI). The registration acceptance message may or may not carry the original allowed NSSAI.

[0341] S1105 and AMF initiate an NSSAA process for each S-NSSAI contained in the pending NSSAI, and obtain the result of the NSSAA process for each S-NSSAI.

[0342] Specifically, the execution process of the NSSAA procedure can be referred to existing technologies and will not be elaborated here.

[0343] S1106. If the result of the NSAA process for all S-NSSAIs included in the pending NSSAI is authentication and authorization failure, then the AMF will not update the original allowed NSSAI determined by the AMF in S1102. This means that the allowed NSSAI determined after the NSAA process (which can be called the new allowed NSSAI) is empty, and there is no identification information for the network slice that the terminal is allowed to access.

[0344] Specifically, S1106 is the same as S1006, so I will not go into details.

[0345] In S1107, the AMF sends the first message and the new allowed NSSAI determined in S1006 to the NSSF. Correspondingly, the NSSF receives the first message and the new allowed NSSAI determined in S1006, and determines the target NSSAI based on the first message and the new allowed NSSAI determined in S1006.

[0346] It should be understood that since the NSSAA process for the pending NSSAI failed in S1106, the new allowed NSSAI is empty. S1107 can be understood as the AMF sending the first message to the NSSF. Accordingly, the NSSF receives the first message and determines the target NSSAI based on the first message.

[0347] Specifically, the AMF can invoke the NSSF's service-oriented operation: the service interface Nnssf_Network Slice Selection Get (Nnssf_NSSelection_Get) sends the first information and the new allowed NSSAI determined in S1006 to the NSSF. Optionally, the AMF also sends an instruction to the NSSF instructing the NSSF to determine the target NSSAI. In response to this instruction, the NSSF determines the target NSSAI based on 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 S1103, the AMF can, in response to the first indication information, obtain the first information from the UE's context after the NSSAA process 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, so that the NSSF can determine the target NSSAI based on the first information and the new allowed NSSAI determined in S1006.

[0349] The process by which NSSF determines the target NSSAI is the same as that by AMF, and will not be described in detail here.

[0350] S1108, NSSF sends target NSSAI to AMF. Correspondingly, AMF receives target NSSAI.

[0351] Specifically, NSSF calls NSSF's service-oriented operation: the service interface Nnssf_NSSelection_Get response returns the target NSSAI to AMF.

[0352] S1109, AMF sends target NSSAI to PCF. Correspondingly, PCF receives target NSSAI from AMF.

[0353] Specifically, S1109 is the same as S608, so I will not go into details.

[0354] S1110, PCF determines the RFSP index corresponding to the target NSSAI based on the target NSSAI, and sends the RFSP index corresponding to the target NSSAI to AMF. Correspondingly, AMF receives the RFSP index corresponding to the target NSSAI from PCF.

[0355] Specifically, S1110 is the same as S609, so I will not go into details.

[0356] Optionally, after obtaining the target NSSAI and its corresponding RFSP index, the AMF can delete the first information stored in the UE's context. Furthermore, if the AMF still stores first indication information in S1003, it can also delete the first indication information after obtaining the target NSSAI and its corresponding RFSP index.

[0357] Since all S-NSSAIs in the pending NSSAI have failed NSAA and the allowed NSSAI is empty, this registration fails, triggering the AMF to initiate a deregistration procedure. Simultaneously, the UE's context on the RAN is released, and during the context release process, the UE is informed of the access frequency point corresponding to the target network slice so that the UE can access the target network slice through a new TA / cell. Specifically, this process is described in S1111 and S1112.

[0358] 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 register / cancel the current network registration.

[0359] S1112. A UE context release request is sent to the RAN. The UE context release request carries the second piece of information: {target NSSAI, RFSP index corresponding to target NSSAI}. Correspondingly, the RAN receives the UE context release request from the AMF.

[0360] The UE context release request can be used to request the release of the UE's context stored on the RAN. In addition to carrying the second information, the UE context release request can also carry the UE's identification information and other information, without restriction.

[0361] S1113. The RAN determines the access frequency information corresponding to the target NSSAI based on the target NSSAI and the RFSP index corresponding to the target NSSAI, and sends the access frequency information corresponding to the target NSSAI to the UE. Correspondingly, the UE receives the access frequency information corresponding to the target NSSAI.

[0362] Specifically, S1113 is the same as S612, so I will not go into details.

[0363] S1114. The UE selects a target cell based on the access frequency information corresponding to the target NSSAI and initiates a registration update procedure to that target cell. For example, according to S1113, after the UE receives the access frequency information corresponding to the target NSSAI from the RAN, the UE selects a cell that supports that access frequency and camps there. The UE then sends a registration request message carrying the requested NSSAI to the AMF through that cell. In this case, the requested NSSAI can be the target NSSAI. Correspondingly, the AMF receives the registration request message from the UE.

[0364] It should be understood that, in addition to the requested NSSAI, the registration request message may also include other information, such as the UE's identification information.

[0365] S1115 and AMF trigger other network elements to complete the registration process based on the received registration request message, enabling the UE to access the network slice corresponding to the target NSSAI at the current location.

[0366] Specifically, the process can be referred to existing technologies, and will not be elaborated here.

[0367] based on Figure 11The method described above, in a 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 also determines that the requested NSSAI includes S-NSSAIs that require NSAA execution (such as pending NSSAI), if all NSAA executions of the pending NSSAI for all S-NSSAIs fail and allowed NSSAI is empty, the AMF is triggered to initiate a deregistration process. At the same time, the AMF obtains the target NSSAI from the NSSF and the RFSP index corresponding to the target NSSAI from the PCF, and sends the target NSSAI and the corresponding RFSP index to the RAN. This triggers the RAN to instruct the UE to select a new TA / new cell for access. This new TA / cell can support all network slices corresponding to the target NSSAI, ensuring that the UE can successfully access the network slice in a scenario where the requested NSSAI includes both S-NSSAIs that the current TA does not support and S-NSSAIs that require NSAA execution.

[0368] It is understood that the methods and / or steps implemented by the mobility management network element in the above embodiments can also be implemented by components (such as chips or circuits) that can be used in the mobility management network element.

[0369] The above mainly describes the solutions provided in the embodiments of this application from the perspective of interaction between various network elements. Correspondingly, the embodiments of this application also provide a communication device, which can be a mobility management network element in the above embodiments, a device containing a mobility management network element, or a component that can be used for a mobility management network element. It is understood that, to implement the above functions, the communication device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0370] For example, taking a communication device as the mobility management network element in the above method embodiment as an example, Figure 12 A schematic diagram of a communication device 120 is shown. This communication device 120 can be a mobility management network element, or a module or chip system used to implement the functions of the mobility management network element in the above method embodiments. Figure 12As shown, the communication device 120 may include a processing unit 120 and a transceiver unit 1202. The transceiver unit 1202, also referred to as a transceiver unit, is used to implement the transceiver function, and may be, for example, a transceiver circuit, a transceiver, a transceiver device, or a communication interface.

[0371] The processing unit 1201 is configured to obtain the identification information of the network slice to be authenticated and authorized from the identification information of the network slice requested by the terminal, initiate the authentication and authorization process for the network slice to be authenticated and authorized, determine the identification information of the network slice that the terminal is allowed to access based on the result of the authentication and authorization process, and obtain second information based on the identification information of the network slice that the terminal is allowed to access and first information; wherein, the first information includes the identification information of the network slice that the terminal is denied access to, or the identification information of the network slice requested by the terminal; the network slice that the terminal is denied access to is a network slice that the access network device in the TA of the network slice requested by the terminal does not support.

[0372] The transceiver unit 1202 is used to send second information to the access network device. The second information includes the identification information of the target network slice and the radio resource information corresponding to the target network slice.

[0373] In one possible design, the processing unit 1201 is specifically used to determine the second information based on the identification information of the network slice that the terminal is allowed to access and the first information. Alternatively, the transceiver unit 1202 sends the identification information of the network slice that the terminal is allowed to access and the first information to the network slice selection function network element, and receives the second information from the network slice selection function network element.

[0374] In one possible design, the transceiver unit 1202 is specifically configured to, if the authentication and authorization process of the network slice to be authenticated and authorized is successful, initiate a user equipment (UE) configuration update process and send a first message including a configuration update command and 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 configuration update process to reduce signaling overhead. 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, a UE context update request carrying the second information is sent to the access network device. 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, a UE context release request carrying the second information is sent to the access network device.

[0375] Among them, the above Figures 5-11 All relevant content of each step involved in the method embodiment shown can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0376] In this embodiment, the communication device 120 is presented in an integrated manner, divided into various functional modules. Here, "module" can refer to a specific ASIC, circuitry, a processor and memory executing one or more software or firmware programs, integrated logic circuitry, and / or other devices that can provide the aforementioned functions. In a simplified embodiment, those skilled in the art will recognize that the communication device 120 can employ... Figure 4 The communication device 400 shown is in the form of [example device].

[0377] for example, Figure 4 The processor 401 in the communication device 400 shown can call computer execution instructions stored in the memory 403 to cause the communication device 400 to execute the method of selecting the tracking area in the above method embodiment.

[0378] Specifically, Figure 12 The functions / implementation process of the transceiver unit 1201 and the processing unit 1202 can be obtained through Figure 4 The processor 401 in the communication device 400 shown calls computer execution instructions stored in the memory 403 to implement the function. Alternatively, Figure 12 The function / implementation process of the processing unit 1202 can be achieved through... Figure 4 The processor 401 in the communication device 400 shown calls computer execution instructions stored in the memory 403 to implement the communication. Figure 12 The function / implementation process of the transceiver unit 1201 can be obtained through Figure 4 This is achieved through the communication interface 404 in the communication device 400 shown.

[0379] Since the communication device 120 provided in this embodiment can execute the above-described method for selecting the tracking area, the technical effects it can achieve can be referred to the above-described method embodiment, and will not be repeated here.

[0380] It should be noted that one or more of the above modules or units can be implemented by software, hardware, or a combination of both. When any of the above modules or units is implemented by software, the software exists as computer program instructions and is stored in memory. The processor can be used to execute the program instructions and implement the above method flow. The processor can be built into a SoC (System-on-Chip) or ASIC, or it can be a separate semiconductor chip. In addition to the core that executes software instructions for computation or processing, the processor may further include necessary hardware accelerators, such as field-programmable gate arrays (FPGAs), PLDs (Programmable Logic Devices), or logic circuits that implement dedicated logic operations. In the embodiments of this 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 devices, discrete gate or transistor logic devices, or discrete hardware components, and can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. A general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly reflected as being executed by a hardware processor, or executed by a combination of hardware and software modules in the processor.

[0381] In the embodiments of this application, the memory can be non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), or it can be volatile memory, such as random-access memory (RAM). Memory is any other medium capable of carrying or storing desired program code in the form of instructions or data structures, and accessible by a computer, but is not limited thereto. The memory in the embodiments of this application can also be a circuit or any other device capable of implementing storage functions, used to store instructions and / or data.

[0382] When the above modules or units are implemented in hardware, the hardware can be any one or any combination of a CPU, microprocessor, digital signal processing (DSP) chip, microcontroller unit (MCU), artificial intelligence processor, ASIC, SoC, FPGA, PLD, application-specific digital circuit, hardware accelerator, or non-integrated discrete device, which can run the necessary software or perform the above method flow independently of software.

[0383] Optionally, embodiments of this application also provide a communication device (e.g., the communication device may be a chip or a chip system), which includes a processor for implementing the methods in any of the above method embodiments. In one possible design, the communication device further includes a memory. The memory is used to store necessary program instructions and data, and the processor can call the program code stored in the memory to instruct the communication device to execute the methods in any of the above method embodiments. Of course, the memory may not be included in the communication device. When the communication device is a chip system, it may be composed of chips or may include chips and other discrete devices; embodiments of this application do not specifically limit this.

[0384] Optionally, embodiments of this application also provide a communication system, the structural diagram of which is shown below. Figure 13 As shown, it may include: terminal 130, access network equipment 131, mobility management network element 132, and may also include network slicing selection function network element 133. It should be noted that... Figure 13 The accompanying drawings are merely illustrative and are not intended to limit the scope of the embodiments described in this application. Figure 13 The communication system shown includes network elements and the number of network elements.

[0385] Among them, mobility management network element 132 has the above-mentioned features. Figures 5 to 11 The mobility management network element functions in one or more of the methods shown. Access network device 131 has the functions described above. Figures 5 to 11 The functions of the first session management network element in one or more of the methods shown. The network slice selection function network element 133 has the above-described functions. Figures 5 to 11 The functions of NSSF in one or more of the methods shown will not be elaborated here.

[0386] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software programs, implementation can be, in whole or in part, in the form of a computer program product. This 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 this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device containing one or more servers, data centers, etc., that can be integrated with the medium. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks (SSDs)).

[0387] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple components. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0388] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A method of selecting a tracking area, characterized by, The method includes: 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; The mobility management network element initiates the authentication and authorization process for the network slice to be authenticated and authorized; The mobility management network element determines the identification information of the network slice that the terminal is allowed to access based on the result of the network slice authentication and authorization process; The mobility management network element obtains second information based on the identification information of the network slice that the terminal is allowed to access and the first information; wherein, the first information includes the identification information of the network slice that the terminal is denied access to; the network slice that the terminal is denied access to is a network slice that is not supported by the tracking area where the access network device is located in the network slice requested by the terminal; the second information includes the identification information of the target network slice and the radio resource information corresponding to the target network slice. The mobility management network element sends the second information to the access network device.

2. The method of claim 1, wherein, The mobility management network element obtains second information based on the identifier information of the network slice that the terminal is allowed to access and the first information, including: The mobility management network element determines the second information based on the identification information of the network slice that the terminal is allowed to access and the first information.

3. The method of claim 2, wherein, The mobility management network element determines the second information based on the identifier information of the network slice that the terminal is allowed to access and the first information, including: The mobility management network element determines the identification information of the network slice that the terminal is denied access to based on the first information; The mobility management network element determines the identification information of the target network slice based on the identification information of the network slice that denies the terminal access and the identification information of the network slice that allows the terminal access.

4. The method of claim 1, wherein, The mobility management network element obtains second information based on the identifier information of the network slice that the terminal is allowed to access and the first information, including: The mobility management network element sends the identification information of the network slice that the terminal is allowed to access and the first information to the network slice selection function network element, and receives the second information from the network slice selection function network element.

5. The method according to any one of claims 1-4, characterized in that, The mobility management network element sends the second information to the access network device, including: Following the terminal registration process, the mobility management network element sends the second information to the access network device.

6. The method according to claim 5, characterized in that, The mobility management network element sends the second information to the access network device, including: If the authentication and authorization process of the network slice to be authenticated and authorized is successful, the mobility management network element sends the second information to the access network device through the user equipment (UE) configuration update process.

7. The method according to claim 5, characterized in that, The mobility management network element sends the second information to the access network device, including: If the authentication and authorization process of the network slice to be authenticated and authorized fails, 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 to the access network device; wherein, the UE context update request includes the second information.

8. The method according to claim 5, characterized in that, The mobility management network element sends the second information to the access network device, including: If the authentication and authorization process of the network slice to be authenticated and authorized fails, 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 to the access network device; wherein, the UE context release request includes the second information.

9. The method according to any one of claims 1-8, characterized in that, The method further includes: The mobility management network element stores the first information.

10. The method according to any one of claims 1-9, characterized in that, The method further includes: 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 process. The mobility management network element obtains second information based on the identification information of the network slice that the terminal is allowed to access and the first information, including: in response to the first indication information, the mobility management network element obtains the second information based on the identification information of the network slice that the terminal is allowed to access and the first information.

11. The method according to claim 9 or 10, characterized in that, The method further includes: The mobility management network element determines that the network slice requested by the terminal contains a network slice that is not supported by the tracking area where the access network device is located.

12. The method according to claim 9 or 10, characterized in that, The method further includes: The mobility management network element deletes the stored first information or the first indication information.

13. A communication device, characterized in that, The communication device includes: The processing unit is used to obtain the identification information of the network slice to be authenticated and authorized from the identification information of the network slice requested by the terminal, and initiate the authentication and authorization process for the network slice to be authenticated and authorized. The processing unit is further configured to determine the identification information of the network slice that the terminal is allowed to access based on the result of the authentication and authorization process of the network slice, and obtain second information based on the identification information of the network slice that the terminal is allowed to access and the first information; wherein, the first information includes the identification information of the network slice that the terminal is denied access to; the network slice that the terminal is denied access to is a network slice that is not supported by the tracking area where the access network device is located in the network slice requested by the terminal, and the second information includes the identification information of the target network slice and the radio resource information corresponding to the target network slice; The transceiver unit is used to send the second information to the access network device.

14. The communication device according to claim 13, characterized in that, The processing unit is specifically used for: The second information is determined based on the identification information of the network slice that the terminal is allowed to access and the first information.

15. The communication device according to claim 14, characterized in that, The processing unit is specifically used for: The identification information of the network slice that the terminal is denied access to is determined based on the first information; The identification information of the target network slice is determined based on the identification information of the network slice that denies the terminal access and the identification information of the network slice that allows the terminal access.

16. The communication device according to claim 13, characterized in that, The processing unit is specifically used for: The transceiver unit sends the identification information of the network slice that the terminal is allowed to access and the first information to the network slice selection function network element, and receives the second information from the network slice selection function network element.

17. The communication device according to any one of claims 13-16, characterized in that, The transceiver unit is specifically used for: After the terminal registration process, the second information is sent to the access network device.

18. The communication device according to claim 17, characterized in that, The transceiver unit is specifically used for: If the authentication and authorization process of the network slice to be authenticated and authorized is successful, the second information is sent to the access network device through the UE configuration update process.

19. The communication device according to claim 17, characterized in that, The transceiver unit is specifically used for: If the authentication and authorization process of the network slice to be authenticated and authorized fails, and the identification information of the network slice that the terminal is allowed to access is not empty, a UE context update request is sent to the access network device; wherein, the UE context update request includes the second information.

20. The communication device according to claim 17, characterized in that, The transceiver unit is specifically used for: If the authentication and authorization process of the network slice to be authenticated and authorized fails, and the identification information of the network slice that the terminal is allowed to access is empty, a UE context release request is sent to the access network device; wherein, the UE context release request includes the second information.

21. The communication device according to any one of claims 13-20, characterized in that, The processing unit is further configured to: Store the first information.

22. The communication device according to any one of claims 13-21, characterized in that, The processing unit is further configured to: Store first indication information; wherein the first indication information is used to indicate one or more of the following: select a new tracking area for the terminal, the new tracking area supporting the target network slice; or, redirect the terminal to a tracking area or frequency band that supports the target network slice; or, obtain the second information after the authentication and authorization process; The processing unit is specifically configured to respond to the first indication information, wherein the mobility management network element obtains the second information based on the identification information of the network slice that the terminal is allowed to access and the first information.

23. The communication device according to claim 21 or 22, characterized in that, The processing unit is further configured to: It is determined that the network slice requested by the terminal contains a network slice that is not supported by the tracking area where the access network device is located.

24. The communication device according to claim 21 or 22, characterized in that, The processing unit is further configured to: Delete the stored first information or the first indication information.

25. A method for selecting a tracking region, characterized in that, The method includes: 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; The mobility management network element initiates the authentication and authorization process for the network slice to be authenticated and authorized; The mobility management network element determines the identification information of the network slice that the terminal is allowed to access based on the result of the network slice authentication and authorization process; The mobility management network element obtains second information based on the identification information of the network slice that the terminal is allowed to access and the first information; wherein, the first information includes the identification information of the network slice that the terminal is denied access to; the network slice that the terminal is denied access to is a network slice that is not supported by the tracking area where the access network device is located in the network slice requested by the terminal; the second information includes the identification information of the target network slice and the radio resource information corresponding to the target network slice. The mobility management network element sends the second information to the access network device; The access network device receives the second information.

26. A communication device, characterized in that, The communication device includes a processor and a communication interface, the processor and the communication interface being configured to support the communication device in performing the method as described in any one of claims 1-12.

27. A communication system, characterized in that, The communication system includes the communication device and access network equipment as described in claim 26, wherein the access network equipment is used to receive the second information.

28. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-12.

29. A computer program product, characterized in that, The computer program product includes computer instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-12.

30. A chip, characterized in that, The chip is coupled to a memory for reading and executing program instructions stored in the memory to implement the method as described in any one of claims 1-12.

Images