AMF selection method and device and storage medium

Abstract

The present application provides an AMF selection method and apparatus, and a storage medium, the method applied to a radio access network RAN comprising: receiving a radio resource management RRC message sent by a terminal, the RRC message carrying a non-access stratum NAS message and attribute information of the terminal; determining a target NF type of a core network specified by the NAS message according to the attribute information of the terminal; when the target NF type is an access and mobility management function AMF, determining an alternative AMF set available for the terminal according to attribute information of the terminal; and selecting a target AMF matched with the terminal from the alternative AMF set. According to the method and the device, the requirement of on-demand connection of the interface is met under the RAN servitization architecture, and the selection flexibility of the signaling transmission path is improved.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to an AMF selection method, device and storage medium. Background Art

[0002] In the existing 5G system, there is a fixed TNL (Transport Network Layer) association (i.e. TNLA, Transport Network Layer Association) between RAN (wireless access network) and the core network AMF (Access and Mobility Management Function) for the communication connection between the two. When UE (User Equipment) needs to transmit signaling with the core network, RAN selects AMF and TNLA, and establishes and maintains the binding relationship between UE and TNLA (i.e. NGAP UE-TNLA-binding, where NGAP: Next Generation Application Protocol) is used for the subsequent transmission of NAS (Non-Access Stratum) signaling.

[0003] After the N2 interface is service-oriented or the RAN adopts a service-oriented architecture, the RAN can interact with any core network NF (Network Functions). There will be no fixed TNL association between the RAN and the AMF, and there is no need to maintain the NGAP UE-TNLA-binding established for the UE. The current technology cannot fully adapt to the service-oriented architecture's requirements for on-demand interface connection and flexibility. Therefore, how the RAN selects the AMF for the UE and maintains the uplink AMF selection path has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] The present application provides an AMF selection method, device and storage medium, which meet the demand for on-demand connection of interfaces under the RAN service-oriented architecture and improve the flexibility of selecting signaling transmission paths.

[0005] In the first aspect, the present application provides an AMF selection method, which is applied to a wireless access network RAN, and the method includes: receiving a radio resource management RRC (Radio Resource Control) message sent by a terminal, the RRC message carrying a non-access layer NAS message and attribute information of the terminal; determining the target NF type of the core network specified by the NAS message according to the attribute information of the terminal; when the target NF type is an access and mobility management function AMF, determining a set of alternative AMFs available to the terminal according to the attribute information of the terminal; and selecting a target AMF that matches the terminal from the set of alternative AMFs.

[0006] In this embodiment, the RAN determines to perform AMF selection according to the information carried by the UE in the RRC message, and then the RAN determines the AMF serving the UE according to the UE information (such as the access RAT type, the UE location information), the UE capabilities and service requirements (such as the delay tolerance indication, the emergency service) and / or the pre-configured AMF auxiliary information, and establishes a route for uplink signaling transmission, thereby meeting the demand for on-demand connection of the interface under the RAN service-oriented architecture and improving the flexibility of selecting the signaling transmission path.

[0007] In one embodiment, the attribute information of the terminal includes: an identifier of the terminal, an indication of a core network NF type, and one or more of the NAS message distribution methods; determining the target NF type specified by the NAS message based on the attribute information of the terminal includes: determining the target NF type of the core network specified by the NAS message based on the identifier of the terminal, an indication of a core network NF type, and one or more of the NAS message distribution methods.

[0008] In this embodiment, the RAN can determine the target NF type of the NAS signaling according to one or more information such as the UE identifier carried in the RRC message, the core network NF type indication, and the matching locally configured NAS message distribution mode. In actual scenarios, appropriate terminal attribute information can be flexibly selected according to actual needs to improve the flexibility of the judgment process.

[0009] In one embodiment, determining the set of alternative AMFs available to the terminal based on the attribute information of the terminal includes: obtaining AMF assistance information locally maintained by the radio access network RAN; determining the set of alternative AMFs available to the terminal based on the attribute information of the terminal and / or the AMF assistance information.

[0010] In this embodiment, AMF assistance information refers to information used to assist in selecting a set of candidate AMFs available to the user. The AMF assistance information can be maintained locally in the RAN, and when AMF selection is required, it is directly read and used locally. The RAN can more accurately select a set of alternative AMFs that can provide services for the terminal UE based on the UE attribute information and / or AMF assistance information, thereby improving the efficiency and accuracy of AMF selection.

[0011] In one embodiment, the attribute information of the terminal includes: one or more of terminal identification, terminal location information, terminal access type, terminal capabilities and business requirements; the AMF auxiliary information includes an optional AMF information set; the determining the available alternative AMF set for the terminal according to the attribute information of the terminal and / or the AMF auxiliary information includes: parsing a first AMF matching the terminal according to the terminal identification, and adding the first AMF to the alternative AMF set; and / or, determining a second AMF for which routing information already exists according to the context information of the terminal locally stored in the RAN, and adding the second AMF to the alternative AMF set; and / or, adding a third AMF in the optional AMF information set that belongs to the same AMF group set as the first AMF or the same AMF group set as the second AMF to the alternative AMF set; and / or, adding a fourth AMF in the optional AMF information set that matches one or more of the terminal location information, the terminal access type, the capabilities and business requirements of the terminal to the alternative AMF set.

[0012] In this embodiment, the RAN can screen and determine the candidate AMF set based on one or more of the terminal UE identification, UE location information, UE access type, UE capabilities and service requirements, locally stored UE context and AMF auxiliary information, and the hypothetical device selection AMF can be provided in the form of a candidate AMF list. Among them, the screening principles of the candidate AMF can include multiple: In actual scenarios, multiple screening principles of the candidate AMF can be flexibly selected to improve the flexibility of interface adaptation.

[0013] In one embodiment, determining the set of alternative AMFs available to the terminal based on the attribute information of the terminal and / or the AMF auxiliary information also includes: configuring priorities for each AMF in the set of alternative AMFs, and priority configuration rules include: configuring the first AMF as the highest level first priority; and / or configuring the second AMF as the second priority, the second priority being less than or equal to the first priority; and / or configuring the third AMF as the third priority, the third priority being less than the second priority.

[0014] In this embodiment, when screening the candidate AMF set, a priority can be configured for each candidate AMF in the candidate AMF set. Optionally, the RAN can screen and establish a prioritized candidate AMF list based on one or more of the UE attribute information (e.g., UE identity, UE location information, UE access type), UE capabilities and service requirements, locally stored UE context (e.g., AMF identity, AMF routing information), and AMF auxiliary information. Among them, the screening and priority principles of the candidate AMF can include one or more. After configuring the priority of each candidate AMF in the candidate AMF set, when subsequently establishing a link, a link message can be sent based on the priority configuration to improve the efficiency of path establishment.

[0015] In one embodiment, the AMF auxiliary information also includes an AMF matching rule set; determining the set of alternative AMFs available to the terminal based on the attribute information of the terminal and / or the AMF auxiliary information also includes: adding a fourth AMF in the optional AMF information set that matches one or more of the terminal location information, the terminal access type, the capabilities and business requirements of the terminal to the alternative AMF set according to the AMF matching rule set; and / or, based on the terminal location information, the terminal access type, the capabilities and business requirements of the terminal, evaluating the first matching degree between each AMF in the fourth AMF and the terminal according to the AMF matching rule set; configuring the fourth priority of each fourth AMF according to the first matching degree, wherein the first matching degree is positively correlated with the fourth priority of the corresponding fourth AMF.

[0016] In this embodiment, in a scenario where it is necessary to configure a priority for each alternative AMF in the alternative AMF set, for the fourth AMF in the optional AMF information set that matches one or more of the terminal location information, the terminal access type, the terminal capabilities and service requirements, the first matching degree between the fourth AMF and the terminal UE can be evaluated based on information such as UE location information, UE access type, UE capabilities and service requirements, and with reference to the information in the AMF matching rule set. The first matching degree is positively correlated with the fourth priority corresponding to the fourth AMF, that is, the higher the first matching degree, the higher the priority of the fourth AMF. Such a priority characterizes the adaptability of the fourth AMF to the terminal UE, which is convenient for preferential selection when establishing a signaling propagation path in the subsequent process, thereby improving efficiency.

[0017] In one embodiment, before obtaining the AMF auxiliary information locally maintained by the wireless access network RAN, it also includes a step of generating the AMF auxiliary information, including: sending a registration request to the network repository function NRF of the core network, the registration request carrying the configuration information of the RAN and the indication of requesting AMF assistance; receiving a response message returned by the NRF, the response message carrying an optional AMF information set and a corresponding AMF matching rule set, wherein the optional AMF information set and the AMF matching rule set are determined by the NRF according to the configuration information of the RAN and the current status and load information of each AMF in the core network; generating the AMF auxiliary information according to the optional AMF information set and the AMF matching rule set.

[0018] In this embodiment, when registering with the RAN, the RAN may obtain the AMF auxiliary information from the network storage function NRF.

[0019] Specifically, the process can be as follows:

[0020] After the RAN node is powered on or the parameters are modified, a RAN registration service request is initiated to the NRF, and the request carries the configuration information of the RAN and the request for AMF assistance indication, wherein the configuration information of the RAN (which may be a RAN profile) includes but is not limited to the RAN node identifier, PLMN (Public Land Mobile Network, Public Land Mobile (Communication) Network) / NPN (Non-Public Network, Non-Public Network) identifier, RAT (Radio Access Technology, Radio Access Technology) type, geographic location information, supported TA (Terminal Adapter, Terminal Adapter) list, slice information, capability information (such as communication, perception) one or more. The request for AMF assistance indication is used to instruct the NRF (Network Repository Function) to determine a set of optional AMF information sets available to the terminal UE and the related AMF matching rule set based on the RAN configuration information, the current capability status and load information of each AMF in the core network. Among them, the optional AMF information set includes but is not limited to: each optional AMF identifier, AMF address identifier, AMF Set information and other contents, which can be in the form of a list. AMF Set refers to the AMF grouping set. In actual scenarios, all AMFs in the core network can be divided into several groups, each of which is called an AMF Set. AMF matching rules may include but are not limited to: the matching degree of each AMF based on RAT type, the matching degree of each AMF based on geographical proximity, and other information.

[0021] Then NRF responds to the RAN registration service request, carrying the generated optional AMF information set and AMF matching rule set in the response message. RAN stores the received optional AMF information set and AMF matching rule set in the AMF auxiliary information. In this way, the network resources of NRF in the core network are fully utilized, the resources of RAN itself are saved, and the resource utilization rate is improved.

[0022] In one embodiment, the step of generating the AMF auxiliary information also includes: sending an AMF auxiliary update request to the NRF, and / or subscribing to an AMF auxiliary information update event to the NRF; receiving the AMF update information returned by the NRF, the AMF update information including an updated optional AMF information set and / or a corresponding updated AMF matching rule set; wherein the updated optional AMF information set and / or the updated AMF matching rule set are determined by the NRF based on the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network; and updating the AMF auxiliary information locally stored in the RAN according to the updated optional AMF information set and the updated AMF matching rule set.

[0023] In this embodiment, in order to maintain the timeliness of AMF auxiliary information, AMF auxiliary information can be updated from NRF. Specifically, in the process of RAN registering with NRF to obtain AMF auxiliary information, the registration service request sent by RAN can carry the reception of AMF auxiliary update request, or RAN can subscribe to the AMF auxiliary information update event to the NRF service, and carry the RAN identifier, reception of AMF auxiliary information indication and other information in the subscription message. The update request or subscription information is used to instruct NRF to monitor the AMF in the optional AMF information set or select a new optional AMF according to the reception of AMF auxiliary update request in the RAN registration request or the AMF auxiliary information update event subscribed by RAN.

[0024] During this process, if the selected AMF configuration information (such as the terminal adapter TA identifier) ​​in the optional AMF information set changes, or the AMF state changes (such as overload, deregistration, connection failure), the NRF updates the optional AMF information set and determines the corresponding updated AMF matching rule set. If a new AMF is online, the NRF can update the new optional AMF to the optional AMF information set and determine the corresponding updated AMF matching rule set. Then the NRF notifies the RAN, and the notification message carries the updated optional AMF information set and / or the updated AMF matching rule set. The RAN updates the local AMF auxiliary information based on the received updated optional AMF information set and the updated AMF matching rule set. In this way, the NRF update function of the core network is used to implement the update of AMF auxiliary information and maintain the timeliness of the AMF auxiliary information.

[0025] In one embodiment, the attribute information of the terminal includes: terminal identification, terminal location information, terminal access type, slice information requested by the terminal, terminal capabilities and service requirements, terminal context stored locally in the RAN, and one or more of the mobile network identification code selected by the terminal; determining the set of alternative AMFs available to the terminal based on the attribute information of the terminal also includes: determining the target NRF that provides services to the terminal based on the mobile network identification code selected by the terminal; determining the set of candidate AMFs available to the terminal based on the terminal identification and / or the terminal context; determining the terminal's demand information for AMF based on the terminal location information, the terminal access type, and one or more of the terminal's capabilities and service requirements; sending an NF discovery request to the target NRF, the NF discovery request carrying the candidate AMF set and the requirement information, the NF discovery request being used to instruct the target NRF to return the set of alternative AMFs available to the terminal; receiving the set of alternative AMFs available to the terminal returned by the target NRF.

[0026] In this embodiment, RAN can select AMF with the assistance of NRF. The mobile network identification code selected by the terminal includes but is not limited to PLMN / NPN information. RAN can select and determine the target NRF that provides services for the terminal according to the selected PLMN / NPN information carried in the RRC message in step 301. Then RAN can determine the preferred AMF (i.e., the candidate AMF set available to the terminal) according to one or more of the information related to AMF in the RRC message (e.g., UE identity) and the locally stored UE context (AMF identity, AMF routing information); RAN determines UE assistance information, wherein UE assistance information is the demand information of the terminal UE for AMF, including but not limited to: UE information such as UE location information and UE access type, as well as one or more of the UE capabilities and service requirements such as requested slice information, support for multiple access indications, and delay tolerance indications. Then, RAN sends a NF discovery request to the target NRF, and the request carries one or more of the preferred AMF and UE assistance information. The NF discovery request is used to instruct the target NRF to return the candidate AMF set available to the terminal, and RAN receives the candidate AMF set available to the terminal returned by the target NRF. In this way, the NRF function of the core network is used to select AMF, which not only saves RAN resources but also improves the resource utilization of the core network and improves efficiency.

[0027] In one embodiment, the candidate AMF set is determined by the target NRF based on the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network.

[0028] In this embodiment, in the scenario where AMF is selected with the assistance of NRF, the target NRF may determine one or more candidate AMF instances based on the preferred AMF provided by RAN, the capability requirements for AMF, and the current state of AMF, and notify RAN. The NF discovery request response message carries the selected candidate AMF identifier, the candidate AMF address identifier, the AMF Set to which it belongs, and other information of the candidate AMF. In this way, the entire determination process of the candidate AMF set can be implemented using the functions of the NRF of the core network, which not only saves RAN resources, but also improves the resource utilization of the core network and improves efficiency.

[0029] In one embodiment, the candidate AMF set is determined by the target NRF based on a second degree of matching between each AMF in the candidate AMF set and the terminal, and the second degree of matching is determined by a network data analysis function NWDAF (Network Data Analytics Function) in the core network based on configuration information of the radio access network RAN, configuration information of each AMF in the candidate AMF set and the demand information.

[0030] In this embodiment, NWDAF can also be used to assist NRF in selecting AMF. After RAN sends an NF discovery request to the target NRF, the target NRF can send a data analysis request to NWDAF in the core network, which carries RAN configuration information (such as RAN location), UE auxiliary information (i.e., UE's demand information for AMF) and each AMF configuration information in the candidate AMF set. The data analysis request is used to instruct NWDAF to analyze the second matching degree between each AMF and UE according to the preset resource usage model of RAN and AMF. Then NWDAF returns the second matching degree analysis result between AMF and UE to the target NRF through a data analysis request response message. The target NRF determines the candidate AMF set based on the second matching degree analysis result between AMF and UE, and sends the candidate AMF information such as each candidate AMF identifier, candidate AMF address identifier, and AMF Set to which it belongs in the candidate AMF set to RAN through an NF discovery request response message. In this way, the target NRF seeks assistance from other functions in the core network, fully utilizes the existing network resources in the core network, and improves the efficiency of AMF selection.

[0031] In one embodiment, the selecting of the target AMF matching the terminal from the candidate AMF set further includes: sending a first message to each AMF in the candidate AMF set in descending order according to the priority of each AMF in the candidate AMF set, wherein the first message carries the terminal identifier and / or the NAS message; determining the first AMF that is determined to be reachable as the target AMF matching the terminal; or determining the first AMF that responds to the NAS message as the target AMF matching the terminal.

[0032] In this embodiment, if each candidate AMF in the candidate AMF set is configured with a priority, the RAN may send a first message to each AMF in the candidate AMF set in order from high to low according to the priority of each AMF in the candidate AMF list. Here, the first message is the first message communicated between the RAN and the target AMF. The first message may be a connection establishment message or an interface establishment message. The communication process may include two situations, the first is to complete the establishment and NAS message response in one time, and the second is to complete it in two times.

[0033] For the first case, for example, the RAN may send a first message carrying the terminal identifier in order from high to low according to the priorities of the AMFs in the candidate AMF list, wherein the first message carries the terminal identifier and the NAS message. At this time, the first AMF that is determined to be reachable may be determined as the target AMF.

[0034] For the second case, the RAN may send a first message carrying the terminal identifier in order from high to low according to the priorities of the AMFs in the candidate AMF list, and the first message carries the terminal identifier. Then, for the candidate AMGs determined to establish a connection, NAS messages are sent in order from high to low according to the priorities, and the first AMF that responds to the NAS message may be determined as the target AMF matching the terminal.

[0035] In one embodiment, selecting the target AMF matching the terminal from the candidate AMF set includes: sending a broadcast message to each AMF in the candidate AMF set, the broadcast message carrying the terminal identifier and the NAS message, and determining the AMF in the candidate AMF set that first responds to the broadcast message as the target AMF matching the terminal.

[0036] In this embodiment, if the candidate AMF set contains multiple candidate AMFs, the RAN can broadcast a message to each candidate AMF, the broadcast message carries the UE identifier and the NAS message, and determines the AMF that first responds to the broadcast message among the candidate AMFs as the target AMF that can serve the UE. After successfully establishing a connection with the target AMF, the target AMF information is stored in the local UE context.

[0037] In one embodiment, after selecting the target AMF matching the terminal from the candidate AMF set, it also includes: after successfully establishing a link with the target AMF, storing the target AMF and the uplink route related to the target AMF in the terminal context.

[0038] In this embodiment, after successfully establishing a link with the target AMF, the RAN may store the target AMF information and the uplink route related to the target AMF in the local UE context for subsequent use.

[0039] In a second aspect, the present application provides an AMF selection method, which is applied to a core network, and the method includes: receiving an NF discovery request sent by a wireless access network RAN, the NF discovery request carrying a candidate AMF set matching a terminal and the terminal's demand information for AMF, wherein the candidate AMF set is determined by the RAN based on the terminal identifier and / or the terminal context locally stored in the RAN, and the demand information is determined by the RAN based on one or more of the terminal location information, the terminal access type, the slice information requested by the terminal, the capabilities and service requirements of the terminal; in response to the NF discovery request, determining the available alternative AMF set for the terminal based on the candidate AMF set, the demand information and the current status and load information of each AMF in the core network; and sending the alternative AMF set information to the RAN.

[0040] In this embodiment, the NRF of the core network generates AMF auxiliary information according to the requirements of the RAN, and updates the AMF auxiliary information; optionally, the NRF can analyze the matching degree of the AMF with the help of the NWDAF to determine the target AMF. In this way, the core network provides auxiliary information to the RAN to assist the RAN in selecting the AMF, and with the assistance of the core network functions, a method is provided to dynamically select the service AMF for the UE and establish an uplink signaling transmission path. It meets the requirements of the service-oriented architecture for establishing connections on demand, flexibly scheduling and managing network resources, and can adapt to various RAN and AMF deployment scenarios. Make full use of the existing network resources in the core network to improve the efficiency and flexibility of AMF selection.

[0041] In one embodiment, the response to the NF discovery request, determining the set of alternative AMFs available to the terminal according to the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, includes: responding to the NF discovery request, determining the set of alternative AMFs available to the terminal through the target NRF in the core network that provides services to the terminal according to the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, wherein the target NRF is determined by the RAN according to the mobile network identification code selected by the terminal.

[0042] In this embodiment, in the scenario where AMF is selected with the assistance of NRF, the target NRF selected by the terminal in the core network can determine one or more candidate AMF instances based on the preferred AMF provided by RAN, the capability requirements for AMF, and the current state of AMF, and notify RAN in the form of an NF discovery request response message. The NF discovery request response message carries the information of the selected candidate AMF identifier, the candidate AMF address identifier, the AMF Set to which it belongs, and so on. In this way, the entire determination process of the candidate AMF set can be implemented by utilizing the functions of NRF in the core network, which not only saves RAN resources, but also improves the resource utilization of the core network and improves efficiency.

[0043] In one embodiment, the response to the NF discovery request, according to the candidate AMF set, the requirement information and the current status and load information of each AMF in the core network, determines the candidate AMF set available to the terminal, including: in response to the NF discovery request, the target NRF providing services for the terminal sends a data analysis request to the network data analysis function NWDAF in the core network, the data analysis request carries the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set and the requirement information, wherein the target NRF is determined by the RAN according to the mobile network identification code selected by the terminal; receiving the second matching degree between each AMF in the candidate AMF set and the terminal returned by the NWDAF, wherein the second matching degree is determined by the NWDAF according to the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set and the requirement information; the target NRF determines the candidate AMF set according to the second matching degree.

[0044] In this embodiment, the NWDAF in the core network can also be used to assist the NRF in selecting AMF. After the RAN sends an NF discovery request to the target NRF in the core network, the target NRF can send a data analysis request to the NWDAF in the core network, which carries RAN configuration information (such as RAN location), UE auxiliary information (i.e., UE's demand information for AMF) and each AMF configuration information in the candidate AMF set. The data analysis request is used to instruct the NWDAF to analyze the second matching degree between each AMF and the UE according to the preset resource usage model of the RAN and AMF. Then the NWDAF returns the second matching degree analysis result between the AMF and the UE to the target NRF through the data analysis request response message. The target NRF determines the candidate AMF set based on the second matching degree analysis result between the AMF and the UE, and sends the candidate AMF information such as the candidate AMF identifier, the candidate AMF address identifier, and the AMFSet to which it belongs in the candidate AMF set to the RAN through the NF discovery request response message. In this way, the target NRF seeks assistance from other functions in the core network, fully utilizes the existing network resources in the core network, and improves the efficiency of AMF selection.

[0045] In one embodiment, it also includes: the target NRF receives a registration request sent by the RAN, the registration request carries the configuration information of the RAN and an AMF assistance indication; in response to the AMF assistance indication, the target NRF determines an optional AMF information set and a corresponding AMF matching rule set according to the configuration information of the RAN and the current status and load information of each AMF in the core network; the target NRF returns a response message to the RAN, wherein the response message carries an optional AMF information set and a corresponding AMF matching rule set.

[0046] In this embodiment, when registering with the RAN, the RAN may obtain the AMF auxiliary information from the network storage function NRF of the core network. Specifically, the process may be as follows:

[0047] After the RAN node is powered on or the parameters are modified, a RAN registration service request is initiated to the NRF of the core network. The request carries the configuration information of the RAN and the request for AMF assistance indication, wherein the configuration information of the RAN (which may be a RAN profile, a RAN configuration file) includes but is not limited to one or more of the RAN node identifier, PLMN / NPN identifier, RAT type, geographic location information, supported TA list, slice information, and capability information (such as communication, perception). The target NRF determines a set of optional AMF information sets available to the terminal UE and a set of related AMF matching rules based on the RAN configuration information, the current capability status and load information of each AMF in the core network. Among them, the optional AMF information set includes but is not limited to: each optional AMF identifier, AMF address identifier, AMF Set information and other contents, which can be in the form of a list. AMF Set refers to an AMF grouping set. In actual scenarios, all AMFs in the core network can be divided into several groups, each of which is called an AMF Set. AMF matching rules may include but are not limited to: the matching degree of each AMF based on the RAT type, the matching degree of each AMF based on geographical proximity and distance, and other information.

[0048] Then the target NRF responds to the RAN registration service request, carrying the generated optional AMF information set and AMF matching rule set in the response message. RAN stores the received optional AMF information set and AMF matching rule set in the AMF auxiliary information. In this way, the network resources of the NRF in the core network are fully utilized, the resources of the RAN itself are saved, and the resource utilization rate is improved.

[0049] In one embodiment, it also includes: the target NRF receives the AMF assisted update request sent by the RAN, and / or the subscription message of the RAN to the AMF assisted information update event; the target NRF determines the updated optional AMF information set and / or the updated AMF matching rule set according to the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network; in response to the AMF assisted update request, the target NRF returns AMF update information to the RAN, and the AMF update information includes the updated optional AMF information set and / or the corresponding updated AMF matching rule set; and / or, in response to the subscription message, the target NRF notifies the RAN of AMF update information, and the AMF update information includes the updated optional AMF information set and the corresponding updated AMF matching rule set.

[0050] In this embodiment, in order to maintain the timeliness of AMF auxiliary information, the core network NRF can provide an AMF auxiliary information update service. Specifically, in the process of RAN registering with NRF to obtain AMF auxiliary information, the registration service request sent by the RAN can carry a request to receive an AMF auxiliary update, or the RAN can subscribe to the AMF auxiliary information update event to the NRF service, and carry the RAN identifier, the indication of receiving AMF auxiliary information, and other information in the subscription message. The target NRF of the core network monitors the AMF in the optional AMF information set or selects a new optional AMF according to the request to receive an AMF auxiliary update in the RAN registration request, or the AMF auxiliary information update event subscribed by the RAN.

[0051] During this process, if the selected AMF configuration information (such as the terminal adapter TA identifier) ​​in the optional AMF information set changes, or the AMF state changes (such as overload, deregistration, connection failure), the NRF updates the optional AMF information set and determines the corresponding updated AMF matching rule set. If a new AMF is online, the NRF can update the new optional AMF to the optional AMF information set and determine the corresponding updated AMF matching rule set. Then the NRF notifies the RAN, and the notification message carries the updated optional AMF information set and / or the updated AMF matching rule set. The RAN updates the local AMF auxiliary information based on the received updated optional AMF information set and the updated AMF matching rule set. In this way, the NRF update function of the core network is used to implement the update of AMF auxiliary information and maintain the timeliness of the AMF auxiliary information.

[0052] In a third aspect, the present application provides an AMF selection device, which is applied to a wireless access network RAN, and the device includes: a memory, a transceiver, and a processor: a memory, which is used to store a computer program; a transceiver, which is used to send and receive data under the control of the processor; a processor, which is used to read the computer program in the memory and perform the following operations: receiving a wireless resource management RRC message sent by a terminal, the RRC message carrying a non-access layer NAS message and attribute information of the terminal; determining a target NF type of the core network specified by the NAS message according to the attribute information of the terminal; when the target NF type is an access and mobility management function AMF, determining a set of alternative AMFs available to the terminal according to the attribute information of the terminal; and selecting a target AMF matching the terminal from the set of alternative AMFs.

[0053] In one embodiment, the attribute information of the terminal includes: an identifier of the terminal, an indication of a core network NF type, and one or more of the NAS message distribution methods; determining the target NF type specified by the NAS message based on the attribute information of the terminal includes: determining the target NF type of the core network specified by the NAS message based on the identifier of the terminal, an indication of a core network NF type, and one or more of the NAS message distribution methods.

[0054] In one embodiment, determining the set of alternative AMFs available to the terminal based on the attribute information of the terminal includes: obtaining AMF assistance information locally maintained by the radio access network RAN; determining the set of alternative AMFs available to the terminal based on the attribute information of the terminal and / or the AMF assistance information.

[0055] In one embodiment, the attribute information of the terminal includes: one or more of terminal identification, terminal location information, terminal access type, terminal capabilities and business requirements; the AMF auxiliary information includes an optional AMF information set; the determining the available alternative AMF set for the terminal according to the attribute information of the terminal and / or the AMF auxiliary information includes: parsing a first AMF matching the terminal according to the terminal identification, and adding the first AMF to the alternative AMF set; and / or, determining a second AMF for which routing information already exists according to the context information of the terminal locally stored in the RAN, and adding the second AMF to the alternative AMF set; and / or, adding a third AMF in the optional AMF information set that belongs to the same AMF group set as the first AMF or the same AMF group set as the second AMF to the alternative AMF set; and / or, adding a fourth AMF in the optional AMF information set that matches one or more of the terminal location information, the terminal access type, the capabilities and business requirements of the terminal to the alternative AMF set.

[0056] In one embodiment, determining the set of alternative AMFs available to the terminal based on the attribute information of the terminal and / or the AMF auxiliary information also includes: configuring priorities for each AMF in the set of alternative AMFs, and priority configuration rules include: configuring the first AMF as the highest level first priority; and / or configuring the second AMF as the second priority, the second priority being less than or equal to the first priority; and / or configuring the third AMF as the third priority, the third priority being less than the second priority.

[0057] In one embodiment, the AMF auxiliary information also includes an AMF matching rule set; determining the set of alternative AMFs available to the terminal based on the attribute information of the terminal and / or the AMF auxiliary information also includes: adding a fourth AMF in the available selected AMF information set that matches one or more of the terminal location information, the terminal access type, the terminal capabilities and business requirements to the alternative AMF set according to the AMF matching rule set; and / or, based on the terminal location information, the terminal access type, the terminal capabilities and business requirements, evaluating the first matching degree between each AMF in the fourth AMF and the terminal according to the AMF matching rule set; configuring the fourth priority of each fourth AMF according to the first matching degree, wherein the first matching degree is positively correlated with the fourth priority of the corresponding fourth AMF.

[0058] In one embodiment, before obtaining the AMF auxiliary information locally maintained by the wireless access network RAN, it also includes a step of generating the AMF auxiliary information, including: sending a registration request to the network repository function NRF of the core network, the registration request carrying the configuration information of the RAN and the AMF auxiliary indication; receiving a response message returned by the NRF, the response message carrying an optional AMF information set and a corresponding AMF matching rule set, wherein the optional AMF information set and the AMF matching rule set are determined by the NRF according to the configuration information of the RAN and the current status and load information of each AMF in the core network; generating the AMF auxiliary information according to the optional AMF information set and the AMF matching rule set.

[0059] In one embodiment, the step of generating the AMF auxiliary information also includes: sending an AMF auxiliary update request to the NRF, and / or subscribing to an AMF auxiliary information update event to the NRF; receiving the AMF update information returned by the NRF, the AMF update information including an updated optional AMF information set and / or a corresponding updated AMF matching rule set; wherein the updated optional AMF information set and / or the updated AMF matching rule set are determined by the NRF based on the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network; and updating the AMF auxiliary information locally stored in the RAN according to the updated optional AMF information set and the updated AMF matching rule set.

[0060] In one embodiment, the attribute information of the terminal includes: terminal identification, terminal location information, terminal access type, slice information requested by the terminal, terminal capabilities and service requirements, terminal context stored locally in the RAN, and one or more of the mobile network identification code selected by the terminal; determining the set of alternative AMFs available to the terminal based on the attribute information of the terminal also includes: determining the target NRF that provides services to the terminal based on the mobile network identification code selected by the terminal; determining the set of candidate AMFs available to the terminal based on the terminal identification and / or the terminal context; determining the terminal's demand information for AMF based on the terminal location information, the terminal access type, and one or more of the terminal's capabilities and service requirements; sending an NF discovery request to the target NRF, the NF discovery request carrying the candidate AMF set and the requirement information, the NF discovery request being used to instruct the target NRF to return the set of alternative AMFs available to the terminal; receiving the set of alternative AMFs available to the terminal returned by the target NRF.

[0061] In one embodiment, the candidate AMF set is determined by the target NRF based on the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network.

[0062] In one embodiment, the candidate AMF set is determined by the target NRF based on a second matching degree between each AMF in the candidate AMF set and the terminal, and the second matching degree is determined by a network data analysis function NWDAF in the core network based on configuration information of the radio access network RAN, configuration information of each AMF in the candidate AMF set and the demand information.

[0063] In one embodiment, the selecting of the target AMF matching the terminal from the candidate AMF set further includes: sending a first message to each AMF in the candidate AMF set in descending order according to the priority of each AMF in the candidate AMF set, wherein the first message carries the terminal identifier and / or the NAS message; determining the first AMF that is determined to be reachable as the target AMF matching the terminal; or determining the first AMF that responds to the NAS message as the target AMF matching the terminal.

[0064] In one embodiment, selecting the target AMF matching the terminal from the candidate AMF set includes: sending a broadcast message to each AMF in the candidate AMF set, the broadcast message carrying the terminal identifier and the NAS message, and determining the AMF in the candidate AMF set that first responds to the broadcast message as the target AMF matching the terminal.

[0065] In a fourth aspect, the present application provides an AMF selection device, applied to a core network, the device comprising: a memory, a transceiver, and a processor:

[0066] A memory for storing a computer program; a transceiver for transmitting and receiving data under the control of the processor; and a processor for reading the computer program in the memory and performing the following operations:

[0067] Receive an NF discovery request sent by a wireless access network RAN, the NF discovery request carrying a candidate AMF set matching the terminal and the terminal's demand information for AMF, wherein the candidate AMF set is determined by the RAN according to the terminal identifier and / or the terminal context locally stored in the RAN, and the demand information is determined by the RAN according to one or more of the terminal location information, the terminal access type, the slice information requested by the terminal, the capabilities and service requirements of the terminal; in response to the NF discovery request, determine the candidate AMF set available to the terminal according to the candidate AMF set, the demand information and the current status and load information of each AMF in the core network; and send the candidate AMF set information to the RAN.

[0068] In one embodiment, the response to the NF discovery request, determining the set of alternative AMFs available to the terminal according to the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, includes: responding to the NF discovery request, determining the set of alternative AMFs available to the terminal through the target NRF in the core network that provides services to the terminal according to the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, wherein the target NRF is determined by the RAN according to the mobile network identification code selected by the terminal.

[0069] In one embodiment, the response to the NF discovery request, according to the candidate AMF set, the requirement information and the current status and load information of each AMF in the core network, determines the candidate AMF set available to the terminal, including: in response to the NF discovery request, the target NRF providing services for the terminal sends a data analysis request to the network data analysis function NWDAF in the core network, the data analysis request carries the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set and the requirement information, wherein the target NRF is determined by the RAN according to the mobile network identification code selected by the terminal; receiving the second matching degree between each AMF in the candidate AMF set and the terminal returned by the NWDAF, wherein the second matching degree is determined by the NWDAF according to the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set and the requirement information; the target NRF determines the candidate AMF set according to the second matching degree.

[0070] In one embodiment, it also includes: the target NRF receives a registration request sent by the RAN, the registration request carries the configuration information of the RAN and an AMF assistance indication; in response to the AMF assistance indication, the target NRF determines an optional AMF information set and a corresponding AMF matching rule set according to the configuration information of the RAN and the current status and load information of each AMF in the core network; the target NRF returns a response message to the RAN, wherein the response message carries an optional AMF information set and a corresponding AMF matching rule set.

[0071] In one embodiment, it also includes: the target NRF receives the AMF assisted update request sent by the RAN, and / or the subscription message of the RAN to the AMF assisted information update event; the target NRF determines the updated optional AMF information set and the updated AMF matching rule set according to the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network; in response to the AMF assisted update request, the target NRF returns AMF update information to the RAN, and the AMF update information includes the updated optional AMF information set and the corresponding updated AMF matching rule set; and / or, in response to the subscription message, the target NRF notifies the RAN of AMF update information, and the AMF update information includes the updated optional AMF information set and the corresponding updated AMF matching rule set.

[0072] In a fifth aspect, the present application provides an AMF selection device, applied to a radio access network RAN, the device comprising:

[0073] A first receiving module, configured to receive a radio resource management RRC message sent by a terminal, wherein the RRC message carries a non-access stratum NAS message and attribute information of the terminal;

[0074] A first determination module, configured to determine a target NF type of the core network specified by the NAS message according to the attribute information of the terminal;

[0075] A second determination module is used to determine, when the target NF type is an access and mobility management function AMF, a candidate AMF set available to the terminal according to the attribute information of the terminal;

[0076] A selection module is used to select a target AMF that matches the terminal from the candidate AMF set.

[0077] In one embodiment, the attribute information of the terminal includes: an identifier of the terminal, an indication of a core network NF type, and one or more of the NAS message distribution methods; the first determination module is used to determine the target NF type of the core network specified by the NAS message based on the identifier of the terminal, the indication of a core network NF type, and one or more of the NAS message distribution methods.

[0078] In one embodiment, the second determination module is used to obtain AMF auxiliary information locally maintained by the radio access network RAN; and determine the set of alternative AMFs available to the terminal based on the attribute information of the terminal and / or the AMF auxiliary information.

[0079] In one embodiment, the attribute information of the terminal includes: one or more of terminal identification, terminal location information, terminal access type, terminal capabilities and business requirements; the AMF auxiliary information includes an optional AMF information set; the second determination module is used to parse out a first AMF matching the terminal according to the terminal identification, and add the first AMF to the alternative AMF set; and / or, determine a second AMF with existing routing information according to the context information of the terminal stored locally in the RAN, and add the second AMF to the alternative AMF set; and / or, add a third AMF in the optional AMF information set that belongs to the same AMF group set as the first AMF or the same AMF group set as the second AMF to the alternative AMF set; and / or, add a fourth AMF in the optional AMF information set that matches one or more of the terminal location information, the terminal access type, the terminal capabilities and business requirements to the alternative AMF set.

[0080] In one embodiment, the second determination module is used to configure the priority of each AMF in the candidate AMF set, and the priority configuration rules include: configuring the first AMF as the highest level first priority; and / or configuring the second AMF as the second priority, the second priority is less than or equal to the first priority; and / or configuring the third AMF as the third priority, the third priority is less than the second priority.

[0081] In one embodiment, the AMF auxiliary information also includes an AMF matching rule set; the second determination module is used to add the fourth AMF in the optional AMF information set that matches one or more of the terminal location information, the terminal access type, the terminal capabilities and business requirements to the alternative AMF set according to the AMF matching rule set; and / or, according to the terminal location information, the terminal access type, the terminal capabilities and business requirements, evaluate the first matching degree between each AMF in the fourth AMF and the terminal according to the AMF matching rule set; configure the fourth priority of each fourth AMF according to the first matching degree, wherein the first matching degree is positively correlated with the fourth priority of the corresponding fourth AMF.

[0082] In one embodiment, it also includes: a first auxiliary module, used to send a registration request to the network repository function NRF of the core network before obtaining the AMF auxiliary information locally maintained by the radio access network RAN, the registration request carrying the configuration information of the RAN and the indication of requesting AMF assistance; receiving a response message returned by the NRF, the response message carrying an optional AMF information set and a corresponding AMF matching rule set, wherein the optional AMF information set and the AMF matching rule set are determined by the NRF according to the configuration information of the RAN and the current status and load information of each AMF in the core network; generating the AMF auxiliary information according to the optional AMF information set and the AMF matching rule set.

[0083] In one embodiment, it also includes: a first update module, used to send an AMF auxiliary update request to the NRF, and / or subscribe to an AMF auxiliary information update event to the NRF; and receive the AMF update information returned by the NRF, the AMF update information including an updated optional AMF information set and / or a corresponding updated AMF matching rule set; wherein the updated optional AMF information set and / or the updated AMF matching rule set are determined by the NRF according to the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network; according to the updated optional AMF information set and the updated AMF matching rule set, the AMF auxiliary information locally stored in the RAN is updated.

[0084] In one embodiment, the attribute information of the terminal includes: terminal identification, terminal location information, terminal access type, slice information requested by the terminal, terminal capabilities and service requirements, terminal context locally stored in the RAN, and one or more of the mobile network identification code selected by the terminal; the second determination module is also used to determine the target NRF that provides services to the terminal based on the mobile network identification code selected by the terminal; determine the set of candidate AMFs available to the terminal based on the terminal identification and / or the terminal context; determine the terminal's demand information for AMF based on the terminal location information, the terminal access type, the terminal's capabilities and service requirements, and one or more of the terminal's requirements; send an NF discovery request to the target NRF, the NF discovery request carrying the candidate AMF set and the requirement information, the NF discovery request being used to instruct the target NRF to return the set of alternative AMFs available to the terminal; receive the set of alternative AMFs available to the terminal returned by the target NRF.

[0085] In one embodiment, the candidate AMF set is determined by the target NRF based on the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network.

[0086] In one embodiment, the candidate AMF set is determined by the target NRF based on a second matching degree between each AMF in the candidate AMF set and the terminal, and the second matching degree is determined by a network data analysis function NWDAF in the core network based on configuration information of the radio access network RAN, configuration information of each AMF in the candidate AMF set and the demand information.

[0087] In one embodiment, the selection module is used to send a first message to each AMF in the candidate AMF set in descending order according to the priority of each AMF in the candidate AMF set, wherein the first message carries the terminal identifier and / or the NAS message; the first AMF that is determined to be reachable is determined as the target AMF that matches the terminal; or the first AMF that responds to the NAS message is determined as the target AMF that matches the terminal.

[0088] In one embodiment, the selection module is used to send a broadcast message to each AMF in the candidate AMF set, where the broadcast message carries the terminal identifier and the NAS message, and determines the AMF in the candidate AMF set that first responds to the broadcast message as the target AMF matching the terminal.

[0089] In one embodiment, it also includes: a storage module, which is used to store the target AMF and the uplink route related to the target AMF in the terminal context after the target AMF matching the terminal is selected from the candidate AMF set and the link with the target AMF is successfully established.

[0090] In a sixth aspect, the present application provides an AMF selection device, applied to a core network, the device comprising:

[0091] A second receiving module is configured to receive an NF discovery request sent by a radio access network RAN, wherein the NF discovery request carries a candidate AMF set matching the terminal and demand information of the terminal for the AMF, wherein the candidate AMF set is determined by the RAN according to the terminal identifier and / or the terminal context locally stored in the RAN, and the demand information is determined by the RAN according to one or more of the terminal location information, the terminal access type, the slice information requested by the terminal, and the capabilities and service requirements of the terminal;

[0092] A response module, configured to respond to the NF discovery request and determine a candidate AMF set available to the terminal according to the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network;

[0093] A sending module is used to send the candidate AMF set information to the RAN.

[0094] In one embodiment, the response module is used to respond to the NF discovery request, and determine the set of candidate AMFs available to the terminal through the target NRF in the core network that provides services to the terminal based on the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, wherein the target NRF is determined by the RAN based on the mobile network identification code selected by the terminal.

[0095] In one embodiment, the response module is used to respond to the NF discovery request, and the target NRF providing services for the terminal sends a data analysis request to the network data analysis function NWDAF in the core network, wherein the data analysis request carries the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set, and the demand information, wherein the target NRF is determined by the RAN according to the mobile network identification code selected by the terminal; receive the second matching degree between each AMF in the candidate AMF set and the terminal returned by the NWDAF, wherein the second matching degree is determined by the NWDAF according to the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set, and the demand information; the target NRF determines the candidate AMF set based on the second matching degree.

[0096] In one embodiment, it also includes: a second auxiliary module, used for the target NRF to receive a registration request sent by the RAN, the registration request carrying the configuration information of the RAN and an AMF auxiliary indication; in response to the AMF auxiliary indication, the target NRF determines an optional AMF information set and a corresponding AMF matching rule set according to the configuration information of the RAN and the current status and load information of each AMF in the core network; the target NRF returns a response message to the RAN, wherein the response message carries an optional AMF information set and a corresponding AMF matching rule set.

[0097] In one embodiment, it also includes: a second update module, which is used for the target NRF to receive the AMF assisted update request sent by the RAN, and / or the subscription message of the RAN to the AMF assisted information update event; the target NRF determines the updated optional AMF information set and / or the updated AMF matching rule set according to the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network; in response to the AMF assisted update request, the target NRF returns AMF update information to the RAN, and the AMF update information includes the updated optional AMF information set and / or the corresponding updated AMF matching rule set; and / or, in response to the subscription message, the target NRF notifies the RAN of AMF update information, and the AMF update information includes the updated optional AMF information set and the corresponding updated AMF matching rule set.

[0098] In a seventh aspect, the present application provides a processor-readable storage medium, wherein the processor-readable storage medium stores a computer program, wherein the computer program is used to enable the processor to execute the method described in any one of the first aspect or the second aspect.

[0099] The present application provides an AMF selection method, device and storage medium, wherein RAN determines to perform AMF selection according to the information carried by UE in the RRC message, wherein the RRC message carries the non-access layer NAS message and the attribute information of the terminal, and when it is determined that the target NF type of the core network specified by the NAS message is AMF, it indicates that a matching AMF needs to be selected for the terminal, and then RAN determines the target AMF of the service for the terminal according to the attribute information of the terminal, so that the terminal establishes a route for uplink signaling transmission according to the target AMF. In this way, the demand for on-demand connection of interfaces is met under the RAN service-oriented architecture, and the flexibility of selecting the signaling transmission path is improved.

[0100] It should be understood that the contents described in the above summary of the invention are not intended to limit the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0102] Figure 1An application scenario architecture diagram of the AMF selection method provided in one embodiment of the present application;

[0103] Figure 2 A schematic diagram of a RAN service-oriented architecture model provided in an embodiment of the present application;

[0104] Figure 3 A schematic diagram of a flow chart of an AMF selection method provided in an embodiment of the present application;

[0105] Figure 4 A schematic diagram of a flow chart of an AMF selection method provided in an embodiment of the present application;

[0106] Figure 5 A schematic diagram of the signaling interaction flow of the AMF auxiliary information generation method provided in an embodiment of the present application;

[0107] Figure 6 A schematic diagram of the signaling interaction flow of the AMF auxiliary information update method provided in an embodiment of the present application;

[0108] Figure 7 A schematic diagram of the signaling interaction process of the AMF selection method provided in one embodiment of the present application;

[0109] Figure 8 A schematic diagram of the signaling interaction process of the AMF selection method provided in one embodiment of the present application;

[0110] Fig. 9 A schematic diagram of the signaling interaction process of the AMF selection method provided in one embodiment of the present application;

[0111] Fig.10 A schematic diagram of the signaling interaction process of the AMF selection method provided in one embodiment of the present application;

[0112] Fig.11 A schematic diagram of the structure of an AMF selection device provided in one embodiment of the present application;

[0113] Fig.12 A schematic diagram of the structure of an AMF selection device provided in one embodiment of the present application;

[0114] Fig.13 A schematic diagram of the structure of an AMF selection device provided in one embodiment of the present application;

[0115] Fig.14 A schematic diagram of the structure of an AMF selection device provided in yet another embodiment of the present application. DETAILED DESCRIPTION

[0116] In the embodiments of the present invention, the term "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0117] In the embodiments of the present application, the term "plurality" refers to two or more than two, and other quantifiers are similar.

[0118] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0119] In order to clearly understand the technical solution of the present application, the terms involved in the embodiments of the present application are first explained:

[0120] 5G: 5th Generation Mobile Communication Technology, fifth generation mobile communication technology.

[0121] UE: User Equipment.

[0122] SMF: Session Management Function, session management function.

[0123] RAN: Radio Access Network.

[0124] AMF: Access and Mobility Management Function, access and mobility management function.

[0125] UDM: Unified Data Management.

[0126] AF: Application Function, application function.

[0127] AUSF: Authentication Server Function, authentication server function device.

[0128] PCF: Policy Control Function, policy control function.

[0129] DN: Data Network, data network.

[0130] UPF: User Plane Function, user plane function.

[0131] NSSF: Network Slice Selection Function, network slice selection function.

[0132] NSSAAF: Network Slice-Specific Authentication and Authorization Function, authentication and authorization function selected by network slices.

[0133] NSACF: Network Slice Admission Control Function, network slice admission control function.

[0134] RRC: Radio Resource Control, radio resource control protocol.

[0135] NGAP: Next Generation Application Protocol, next generation application protocol.

[0136] TNL: Transport Network Layer, transport network layer.

[0137] TNLA: Transport Network Layer Association, transport network layer association.

[0138] NSSAI: Network Slice Selection Assistance Information, network slice selection assistance information / network slice selection auxiliary information.

[0139] 5G-S-TMSI: 5G S-Temporary Mobile Subs cription Identifier, temporary mobile subscription identifier.

[0140] GUAMI: Globally Unique AMF Identifier, globally unique AMF identifier.

[0141] SNPN: Stand-alone Non-Public Network, independent non-public network.

[0142] CIoT: Cellular Internet of Things.

[0143] 6G: 6th generation mobile networks, the sixth generation mobile communication standard.

[0144] NF: Network Functions.

[0145] RRC: Radio Resource Control, radio resource control protocol.

[0146] NAS: Non-Access Stratum, non-access layer.

[0147] NRF: Network Repository Function, network storage function.

[0148] RAT: Radio Access Technology, wireless access technology.

[0149] TA: Terminal Adapter, terminal adapter.

[0150] GUTI: Globally Unique Temporary UE Identity, globally unique temporary UE identity.

[0151] PLMN: Public Land Mobile Network, public land mobile (communication) network.

[0152] NPN: Non-Public Network, non-public network.

[0153] NWDAF: Network Data Analytics Function, network data analysis function.

[0154] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0155] The technical solution provided in the embodiment of the present application can be applicable to a variety of systems, especially 5G systems. For example, the applicable system can be a global system of mobile communication (GSM) system, a code division multiple access (CDMA) system, a wideband code division multiple access (WCDMA) general packet radio service (GPRS) system, a long term evolution (LTE) system, a LTE frequency division duplex (FDD) system, a LTE time division duplex (TDD) system, an advanced long term evolution (LTE-A) system, a universal mobile telecommunication system (UMTS), a world-wide interoperability for microwave access (WiMAX) system, a 5G new air interface (NR) system, etc. These various systems include terminal equipment and network equipment. The system may also include a core network part, such as an evolved packet system (EPS), a 5G system (5GS), etc.

[0156] The terminal device involved in the embodiment of the present application may be a device that provides voice and / or data connectivity to a user, a handheld device with a wireless connection function, or other processing devices connected to a wireless modem. In different systems, the name of the terminal device may also be different. For example, in a 5G system, the terminal device may be called a user equipment (UE). A wireless terminal device can communicate with one or more core networks (CN) via a radio access network (RAN). The wireless terminal device may be a mobile terminal device, such as a mobile phone (or a "cellular" phone) and a computer with a mobile terminal device. For example, it may be a portable, pocket-sized, handheld, computer-built-in or vehicle-mounted mobile device that exchanges language and / or data with a wireless access network. For example, personal communication service (PCS) phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs) and other devices. The wireless terminal device may also be referred to as a system, a subscriber unit, a subscriber station, a mobile station, a mobile station, a remote station, an access point, a remote terminal device, an access terminal device, a user terminal device, a user agent, and a user device, but is not limited in the embodiments of the present application.

[0157] The network device involved in the embodiment of the present application may be a base station, which may include multiple cells providing services for the terminal. Depending on the specific application scenario, the base station may also be called an access point, or may be a device in the access network that communicates with the wireless terminal device through one or more sectors on the air interface, or other names. The network device may be used to interchange received air frames with Internet Protocol (IP) packets, and serve as a router between the wireless terminal device and the rest of the access network, wherein the rest of the access network may include an Internet Protocol (IP) communication network. The network device may also coordinate the attribute management of the air interface. For example, the network device involved in the embodiments of the present application may be a network device (Base Transceiver Station, BTS) in the Global System for Mobile communications (Global System for Mobile communications, GSM) or Code Division Multiple Access (Code Division Multiple Access, CDMA), or a network device (NodeB) in Wide-band Code Division Multiple Access (WCDMA), or an evolutionary network device (evolutional Node B, eNB or e-NodeB) in the long term evolution (long term evolution, LTE) system, a 5G base station (gNB) in the 5G network architecture (next generation system), or a home evolved Node B (Home evolved Node B, HeNB), a relay node, a home base station (femto), a pico base station (pico), etc., which is not limited in the embodiments of the present application. In some network structures, the network device may include a centralized unit (CU) node and a distributed unit (DU) node, and the centralized unit and the distributed unit may also be arranged geographically separately.

[0158] Network devices and terminal devices can each use one or more antennas for multiple-input multiple-output (MIMO) transmission. MIMO transmission can be single-user MIMO (SU-MIMO) or multi-user MIMO (MU-MIMO). Depending on the form and number of antenna combinations, MIMO transmission can be 2D-MIMO, 3D-MIMO, FD-MIMO or massive-MIMO, or it can be diversity transmission, precoded transmission or beamforming transmission, etc.

[0159] The following takes the 5G system scenario as an example to explain the embodiments of the present application in detail.

[0160] like Figure 1 As shown, a schematic diagram of a 5G system architecture based on a reference point form provided by an embodiment of the present application, the system may mainly include: AMF, session management function device SMF, radio access network RAN, authentication server function device AUSF, unified data management device UDM, policy control function device PCF, data network DN, user plane function device UPF) 108, user equipment UE, network slice selection function NSSF, network slice selection authentication and authorization function NSSAAF, network slice admission control function NSACF. Among them, the UE is connected to the AMF through the N1 interface, and the UE is connected to the RAN through the Uu interface and based on the radio resource control protocol RRC. The RAN is connected to the AMF through the N2 interface, and the RAN is connected to the UPF through the N3 interface. Multiple UPFs are connected through the N9 interface, the UPF is connected to the DN through the N6 interface, and the UPF is connected to the SMF through the N4 interface. The SMF is connected to the PCF through the N7 interface, the SMF is connected to the UDM through the N10 interface, and the SMF is connected to the AMF through the N11 interface. Multiple AMFs are connected through the N14 interface, AMF is connected to UDM through the N8 interface, AMF is connected to AUSF through the N12 interface, AMF is connected to NSSF through the N22 interface, AMF is connected to NSSAAF through the N58 interface, and AMF is connected to PCF through the N15 interface. AUSF is connected to UDM through the N13 interface. AMF and SMF obtain user contract data from UDM through the N8 and N10 interfaces respectively, and obtain policy data from PCF through the N15 and N7 interfaces. SMF controls UPF through the N4 interface. In addition, NSSAAF is connected to UDM through the N59 interface, AMF is connected to NSACF through the N80 interface, and SMF is connected to NSACF through the N81 interface.

[0161] Among them, the control plane interface between RAN and AMF is N2, which adopts the NGAP protocol.

[0162] The N2 interface architecture (3GPP TS23.501 5.21.1) is as follows:

[0163] RAN supports establishing multiple fixed TNL associations with each AMF and maintains the binding relationship between UE and TNLA for uplink signaling transmission of the UE. When the UE is in CM-Connected state (indicating that a signaling connection is established between the UE and the core network AMF), RAN maintains the same NGAP UE-TNLA-binding (i.e., uses the same TNL association and NGAP association) until the AMF updates or releases the binding relationship.

[0164] The mechanism for RAN to select AMF (3GPP TS23.501 6.3.5) is as follows:

[0165] The RAN needs to select an AMF instance for a given UE. If the AMF cannot provide appropriate services to the UE (for example, the allowed NSSAI has changed), or reselection is required due to a location change, the initially selected AMF must assign a new AMF to the UE. Other core network NFs (such as SMF) support the AMF selection function to select an AMF from the AMF set when the original AMF serving the UE is unavailable.

[0166] AMF Set refers to the AMF grouping set. In actual scenarios, all AMFs in the core network can be divided into several groups, each of which is called an AMF Set. In the following scenarios, the RAN needs to select an AMF Set and choose an AMF from the AMF Set to serve the UE.

[0167] 1) When the UE does not provide 5G-S-TMSI or GUAMI to the 5G-AN.

[0168] 2) When the UE provides a 5G-S-TMSI or GUAMI to the 5G-AN, but the routing information (i.e. AMF set ID, AMF pointer identifier) ​​indicated in the 5G-S-TMSI or GUAMI is insufficient and / or unavailable (for example, the GUAMI provided by the UE carries an AMF area ID from a different area).

[0169] 3) The AMF has informed the AN that the AMF (identified by GUAMI(s)) is unavailable and the target AMF is not identified and / or the AN has detected that the AMF has failed.

[0170] 4) When the UE attempts to establish a signaling connection and the following conditions are met:

[0171] --5G-AN knows the country where the UE is located; and

[0172] --The AMF to which the 5G-AN establishes a connection is serving different PLMNs in different countries; and

[0173] --The UE provides a 5G-S-TMSI or GUAMI and the calculated AMF serves a country different from the current UE location; and

[0174] --5G-AN is configured to implement AMF selection based on the user's current country.

[0175] Then the 5G-AN needs to select a PLMN whose AMF can serve the UE's current location.

[0176] The factors that RAN needs to consider when selecting AMF Set are as follows:

[0177] --AMF region ID and AMF set ID calculated by GUAMI;

[0178] --Request NSSAI;

[0179] --Local operator policies;

[0180] --5G CIoT features carried by the UE in the RRC message;

[0181] --IAB-instructions.

[0182] --NB-IoT RAT type.

[0183] --Cat-M indication;

[0184] --NRRedCap instruction;

[0185] --SNPN activation indication, as indicated by the UE's RRC message.

[0186] Factors that RAN needs to consider when selecting AMF from AMF Set:

[0187] --Availability of candidate AMFs.

[0188] --Load balancing among candidate AMFs (e.g., considering the weight factors of the candidate AMFs in the AMF set).

[0189] --In 5G-AN, 5G CIoT features carried by UE in RRC messages.

[0190] --In 5G-AN, the SNPN start indication indicated in the RRC message.

[0191] When a UE that already carries 5G-S-TMSI or 5G-GUAMI accesses the network, if more than one AMF is available, the weight of the AMF will be considered.

[0192] Among the technologies related to RAN service, the 5G core network has introduced the Service Based Architecture (SBA), but the wireless access network still uses the traditional hierarchical structure, which cannot well support the scenario requirements and technological evolution of future wireless networks. Therefore, the industry consensus is that RAN service technology research will become an important part of achieving efficient, elastic and open network ecology. The China IMT-2030 Promotion Group lists service-based architecture, network virtualization implemented by cloud native, microservice architecture and other features as important enabling factors for the end-to-end programmable network architecture of each network element of the control plane programmable and user plane for 6G, in order to enhance the agility and flexibility of the network structure and provide consumers with innovative communication services.

[0193] like Figure 2 As shown in the white paper "Technology innovations for 6G system architecture" published by Nokia Bell Labs, possible RAN service-oriented architecture models b) and c) are described, where b) is Service based RAN-core interface and c) is Service based RAN and core interface. At this time, RAN does not have a point-to-point N2 interface with AMF.

[0194] In the aforementioned related technologies, the AMF resources that can be selected when RAN selects AMF for UE are limited by whether the AMF has an established TNL association, and it is necessary to establish and maintain the binding relationship between UE and TNLA (NGAP UE-TNLA-binding) for the subsequent transmission of uplink NAS signaling. After RAN service-oriented, the N2 interface structure changes, and there is no fixed TNL association between RAN and AMF. However, RAN service-oriented research is still in the initial exploration stage, and the current technology cannot fully adapt to the service-oriented architecture's requirements for on-demand interface connection and flexibility.

[0195] In order to solve the above technical problems, the embodiments of the present application provide an AMF selection method, device and storage medium, wherein the RAN determines the execution of AMF selection according to the information carried by the UE in the RRC message, and then the RAN determines the AMF serving the UE according to the UE information (such as access RAT type, UE location information), UE capabilities and service requirements (such as delay tolerance indication, emergency services) and / or pre-configured AMF auxiliary information, establishes a route for uplink signaling transmission, and realizes the requirement for on-demand connection of interfaces under the RAN service-oriented architecture, thereby improving the flexibility of selecting the signaling transmission path.

[0196] The AMF selection method provided in the embodiment of the present application may include at least the following two types of solutions:

[0197] Method 1: RAN determines AMF based on auxiliary information from the core network.

[0198] Method 2: RAN assists NRF in selecting AMF.

[0199] Some embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the case where there is no conflict between the embodiments, the following embodiments and the features in the embodiments can be combined with each other. In addition, the step sequence in the following method embodiments is only an example and not a strict limitation.

[0200] Among them, the method and the device are based on the same inventive concept. Since the principles of solving problems by the method and the device are similar, the implementation of the device and the method can refer to each other, and the repeated parts will not be repeated.

[0201] like Figure 3 As shown, the embodiment of the present application provides an AMF selection method, which can be applied to Figure 1 In the application scenario of the 5G system structure shown in FIG. Figure 1 The RAN shown is executed to meet the demand for on-demand connection of interfaces under the RAN service-oriented architecture and improve the flexibility of selecting signaling transmission paths. The method includes the following steps:

[0202] Step 301: Receive a radio resource management RRC message sent by a terminal, where the RRC message carries a non-access stratum NAS message and attribute information of the terminal.

[0203] In this step, radio resource control RRC refers to the management, control and scheduling of radio resources through certain strategies and means, and makes full use of limited wireless network resources as much as possible while meeting the requirements of service quality, ensuring that the planned coverage area is reached, and improving service capacity and resource utilization as much as possible. In actual scenarios, the terminal UE can send an RRC message carrying non-access layer NAS messages and terminal attribute information to the RAN according to its own business needs, where the NAS message can be, for example, a registration message or a service request message. The attribute information of the terminal UE may include: UE identification, core network NF type indication, matching locally configured NAS message distribution mode and one or more other information.

[0204] Step 302: Determine the target NF type of the core network specified by the NAS message according to the attribute information of the terminal.

[0205] In this step, the RAN can determine the target network function NF type of the core network specified by the NAS message based on the UE attribute information carried in the RRC message to determine the network function service required by the terminal.

[0206] In one embodiment, the terminal attribute information includes: one or more of the terminal UE identifier, the core network NF type indication, and the NAS message distribution mode. Step 302 may specifically include: determining the target NF type of the core network specified by the NAS message according to one or more of the terminal identifier, the core network NF type indication, and the NAS message distribution mode.

[0207] In this embodiment, the RAN can determine the target NF type of the NAS signaling according to one or more information such as the UE identifier carried in the RRC message, the core network NF type indication, and the matching locally configured NAS message distribution mode. In actual scenarios, appropriate terminal attribute information can be flexibly selected according to actual needs to improve the flexibility of the judgment process.

[0208] Step 303: When the target NF type is access and mobility management function AMF, determine the set of candidate AMFs available to the terminal according to the attribute information of the terminal.

[0209] In this step, assuming that RNA determines that the target NF type of NAS signaling is AMF based on one or more information such as the UE identifier carried in the RRC message, the core network NF type indication, and the matching locally configured NAS message distribution method, RNA can select AMF for the terminal UE based on the terminal's attribute information. In this way, the AMF selection process is executed by the wireless access network RAN, and the set of alternative AMFs available to the terminal is automatically adapted.

[0210] In one embodiment, step 303 may specifically include: obtaining AMF assistance information locally maintained by the radio access network RAN. Determining a candidate AMF set available to the terminal according to the terminal's attribute information and / or the AMF assistance information.

[0211] In this embodiment, AMF assistance information refers to information used to assist in selecting a set of candidate AMFs available to the user. The AMF assistance information can be maintained locally in the RAN, and when AMF selection is required, it is directly read and used locally. The RAN can more accurately select a set of alternative AMFs that can provide services for the terminal UE based on the UE attribute information and / or AMF assistance information, thereby improving the efficiency and accuracy of AMF selection.

[0212] In one embodiment, in step 303, before obtaining the AMF auxiliary information maintained locally in the radio access network RAN, a step of generating AMF auxiliary information is also included, including: sending a registration request to the network repository function NRF of the core network, the registration request carrying the configuration information of the RAN and the indication of requesting AMF assistance. Receive a response message returned by the NRF, the response message carrying an optional AMF information set and a corresponding AMF matching rule set, wherein the optional AMF information set and the AMF matching rule set are determined by the NRF based on the configuration information of the RAN and the current status and load information of each AMF in the core network. Generate AMF auxiliary information based on the optional AMF information set and the AMF matching rule set.

[0213] In this embodiment, when registering with the RAN, the RAN may obtain the AMF auxiliary information from the network storage function NRF.

[0214] Specifically, the process can be as follows:

[0215] After the RAN node is powered on or the parameters are modified, a RAN registration service request is initiated to the NRF, and the request carries the RAN configuration information and the request AMF assistance indication, wherein the RAN configuration information (which may be a RAN profile, a RAN configuration file) includes but is not limited to one or more of the RAN node identifier, PLMN / NPN identifier, RAT type, geographic location information, supported TA list, slice information, and capability information (such as communication, perception). The request for AMF assistance indication is used to instruct the NRF to determine a set of optional AMF information sets available to the terminal UE and a set of related AMF matching rules based on the RAN configuration information, the current capability status and load information of each AMF in the core network. Among them, the optional AMF information set includes but is not limited to: each optional AMF identifier, AMF address identifier, AMF Set information and other contents, which can be in the form of a list. AMF Set refers to an AMF grouping set. In actual scenarios, all AMFs in the core network can be divided into several groups, each of which is called an AMF Set. AMF matching rules may include but are not limited to: the matching degree of each AMF based on the RAT type, the matching degree of each AMF based on geographical proximity and distance, and other information.

[0216] Then NRF responds to the RAN registration service request, carrying the generated optional AMF information set and AMF matching rule set in the response message. RAN stores the received optional AMF information set and AMF matching rule set in the AMF auxiliary information. In this way, the network resources of NRF in the core network are fully utilized, the resources of RAN itself are saved, and the resource utilization rate is improved.

[0217] In one embodiment, the step of generating AMF auxiliary information before obtaining the AMF auxiliary information maintained locally in the wireless access network RAN ​​in step 303 may also include: sending an AMF auxiliary update request to the NRF, and / or subscribing to the AMF auxiliary information update event to the NRF. Receive the AMF update information returned by the NRF, the AMF update information includes the updated optional AMF information set and / or the corresponding updated AMF matching rule set. The updated optional AMF information set and / or the updated AMF matching rule set are determined by the NRF based on the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network. According to the updated optional AMF information set and the updated AMF matching rule set, the AMF auxiliary information stored locally in the RAN is updated.

[0218] In this embodiment, in order to maintain the timeliness of AMF auxiliary information, AMF auxiliary information can be updated from NRF. Specifically, in the process of RAN registering with NRF to obtain AMF auxiliary information, the registration service request sent by RAN can carry the reception of AMF auxiliary update request, or RAN can subscribe to the AMF auxiliary information update event to the NRF service, and carry the RAN identifier, reception of AMF auxiliary information indication and other information in the subscription message. The update request or subscription information is used to instruct NRF to monitor the AMF in the optional AMF information set or select a new optional AMF according to the reception of AMF auxiliary update request in the RAN registration request or the AMF auxiliary information update event subscribed by RAN.

[0219] During this process, if the selected AMF configuration information (such as the terminal adapter TA identifier) ​​in the optional AMF information set changes, or the AMF state changes (such as overload, deregistration, connection failure), the NRF updates the optional AMF information set and determines the corresponding updated AMF matching rule set. If a new AMF is online, the NRF can update the new optional AMF to the optional AMF information set and determine the corresponding updated AMF matching rule set. Then the NRF notifies the RAN, and the notification message carries the updated optional AMF information set and / or the updated AMF matching rule set. The RAN updates the local AMF auxiliary information based on the received updated optional AMF information set and the updated AMF matching rule set. In this way, the NRF update function of the core network is used to realize the update of AMF auxiliary information and maintain the timeliness of the AMF auxiliary information.

[0220] In one embodiment, the attribute information of the terminal includes: one or more of the terminal identification, terminal location information, terminal access type, terminal capabilities and business requirements. The AMF auxiliary information includes an optional AMF information set. Step 303 may specifically include: parsing the first AMF that matches the terminal according to the terminal identification, and adding the first AMF to the alternative AMF set. And / or, determining the second AMF with existing routing information according to the context information of the terminal stored locally in the RAN, and adding the second AMF to the alternative AMF set. And / or, adding the third AMF in the optional AMF information set that belongs to the same AMF group set as the first AMF or the same AMF group set as the second AMF to the alternative AMF set. And / or, adding the fourth AMF in the optional AMF information set that matches one or more of the terminal location information, terminal access type, terminal capabilities and business requirements to the alternative AMF set.

[0221] In this embodiment, the RAN may screen and determine the candidate AMF set based on one or more of the terminal UE identification, UE location information, UE access type, UE capability and service requirements, locally stored UE context and AMF auxiliary information, and the assuming device selected AMF may be provided in the form of a candidate AMF list. Among them, the screening principles of the candidate AMF may include but are not limited to the following:

[0222] The first AMF that matches the UE parsed from the UE identifier (e.g., 5G-S-TMSI or 5G-GUTI) may be included in the candidate AMF list.

[0223] The second AMF for which routing information is already determined based on the locally stored UE context may enter the list of candidate AMFs.

[0224] In the optional AMF information set, the third AMF that belongs to the same AMF Set as the first AMF parsed by the UE identity (e.g. GUAMI) or the same AMF Set as the second AMF with existing routing information can be included in the candidate AMF list.

[0225] The fourth AMF in the optional AMF information set that matches all or part of the UE location information, UE access type, UE capabilities and service requirements is added to the candidate AMF list.

[0226] In actual scenarios, multiple screening principles for alternative AMFs can be flexibly selected to improve the flexibility of interface adaptation.

[0227] In one embodiment, step 303 may further specifically include: configuring a priority for each AMF in the candidate AMF set, and the priority configuration rule includes: configuring the first AMF as the first priority with the highest level. And / or, configuring the second AMF as the second priority, the second priority is less than or equal to the first priority. And / or, configuring the third AMF as the third priority, the third priority is less than the second priority.

[0228] In this embodiment, when screening the candidate AMF set, a priority can be configured for each candidate AMF in the candidate AMF set. Optionally, the RAN can screen and establish a prioritized candidate AMF list based on one or more of the UE attribute information (e.g., UE identity, UE location information, UE access type), UE capabilities and service requirements, locally stored UE context (e.g., AMF identity, AMF routing information), and AMF auxiliary information. Among them, the screening and priority principles of the candidate AMF may include:

[0229] The first AMF configuration parsed from the UE identity (e.g. 5G-S-TMSI or 5G-GUTI) has a higher priority, assuming the first priority.

[0230] Determine, based on the locally stored UE context, that the second AMF for which routing information already exists is configured as a higher priority, assuming that the second priority is configured, and the second priority is less than or equal to the first priority.

[0231] In the optional AMF information set, the third AMF that belongs to the same AMF Set as the first AMF parsing the UE identity (e.g. GUAMI) or the same AMF Set as the second AMF with existing routing information is configured as a higher priority. Assuming that the priority is configured as security, the third priority can be lower than the second priority.

[0232] After configuring the priority of each candidate AMF in the candidate AMF set, when subsequently establishing a link, the link message can be sent preferentially according to the priority configuration, thereby improving the efficiency of path establishment.

[0233] In one embodiment, the AMF auxiliary information also includes an AMF matching rule set. Step 303 may also specifically include: according to the AMF matching rule set, adding the fourth AMF in the optional AMF information set that matches one or more of the terminal location information, terminal access type, terminal capabilities and business requirements to the alternative AMF set. And / or, based on the terminal location information, terminal access type, terminal capabilities and business requirements, the first matching degree between each AMF in the fourth AMF and the terminal is evaluated according to the AMF matching rule set. The fourth priority of each fourth AMF is configured according to the first matching degree, wherein the first matching degree is positively correlated with the fourth priority of the corresponding fourth AMF.

[0234] In this embodiment, in a scenario where it is necessary to configure a priority for each alternative AMF in the alternative AMF set, for the fourth AMF in the optional AMF information set that matches one or more of the terminal location information, terminal access type, terminal capabilities and service requirements, the first matching degree between the fourth AMF and the terminal UE can be evaluated based on information such as UE location information, UE access type, UE capabilities and service requirements, and with reference to the information in the AMF matching rule set. The first matching degree is positively correlated with the fourth priority of the corresponding fourth AMF, that is, the higher the first matching degree, the higher the priority of the fourth AMF. Such a priority characterizes the compatibility of the fourth AMF with the terminal UE, which is convenient for selecting the best option when establishing a signaling propagation path in the subsequent process, thereby improving efficiency.

[0235] In one embodiment, the attribute information of the terminal includes: terminal identification, terminal location information, terminal access type, slice information requested by the terminal, terminal capabilities and service requirements, terminal context stored locally in the RAN, and one or more of the mobile network identification code selected by the terminal. Step 303 may also include: determining the target NRF that provides services to the terminal based on the mobile network identification code selected by the terminal. Determine the set of candidate AMFs available to the terminal based on the terminal identification and / or terminal context. Determine the terminal's demand information for AMF based on one or more of the terminal location information, terminal access type, terminal capabilities and service requirements. Send an NF discovery request to the target NRF, the NF discovery request carries a candidate AMF set and requirement information, and the NF discovery request is used to instruct the target NRF to return the set of alternative AMFs available to the terminal. Receive the set of alternative AMFs available to the terminal returned by the target NRF.

[0236] In this embodiment, RAN can select AMF with the assistance of NRF. The mobile network identification code selected by the terminal includes but is not limited to PLMN / NPN information. RAN can select and determine the target NRF that provides services to the terminal based on the selected PLMN / NPN information carried in the RRC message in step 301. Then RAN can determine the preferred AMF (i.e., the set of candidate AMFs available to the terminal) based on one or more of the information related to AMF in the RRC message (e.g., UE identity) and the locally stored UE context (AMF identity, AMF routing information). RAN determines UE assistance information, wherein UE assistance information is the demand information of the terminal UE for AMF, including but not limited to: UE information such as UE location information and UE access type, as well as one or more of the UE capabilities and service requirements such as the requested slice information, support for multiple access indications, and delay tolerance indications. Then, RAN sends a NF discovery request to the target NRF, and the request carries one or more of the preferred AMF and UE assistance information. The NF discovery request is used to instruct the target NRF to return the set of candidate AMFs available to the terminal, and RAN receives the set of candidate AMFs available to the terminal returned by the target NRF. In this way, the NRF function of the core network is used to select AMF, which not only saves RAN resources but also improves the resource utilization of the core network and improves efficiency.

[0237] In one embodiment, the candidate AMF set is determined by the target NRF based on the candidate AMF set, demand information, and the current status and load information of each AMF in the core network.

[0238] In this embodiment, in the scenario where AMF is selected with the assistance of NRF, the target NRF may determine one or more candidate AMF instances based on the preferred AMF provided by RAN, the capability requirements for AMF, and the current state of AMF, and notify RAN. The NF discovery request response message carries the selected candidate AMF identifier, the candidate AMF address identifier, the AMF Set to which it belongs, and other information of the candidate AMF. In this way, the entire determination process of the candidate AMF set can be implemented using the functions of the NRF of the core network, which not only saves RAN resources, but also improves the resource utilization of the core network and improves efficiency.

[0239] In one embodiment, the candidate AMF set is determined by the target NRF based on the second matching degree between each AMF in the candidate AMF set and the terminal, and the second matching degree is determined by the network data analysis function NWDAF in the core network based on the configuration information of the radio access network RAN, the configuration information of each AMF in the candidate AMF set and the demand information.

[0240] In this embodiment, NWDAF can also be used to assist NRF in selecting AMF. After RAN sends an NF discovery request to the target NRF, the target NRF can send a data analysis request to NWDAF in the core network, which carries RAN configuration information (such as RAN location), UE auxiliary information (i.e., UE's demand information for AMF) and each AMF configuration information in the candidate AMF set. The data analysis request is used to instruct NWDAF to analyze the second matching degree between each AMF and UE according to the preset resource usage model of RAN and AMF. Then NWDAF returns the second matching degree analysis result between AMF and UE to the target NRF through a data analysis request response message. The target NRF determines the candidate AMF set based on the second matching degree analysis result between AMF and UE, and sends the candidate AMF information such as each candidate AMF identifier, candidate AMF address identifier, and AMF Set to which it belongs in the candidate AMF set to RAN through an NF discovery request response message. In this way, the target NRF seeks assistance from other functions in the core network, fully utilizes the existing network resources in the core network, and improves the efficiency of AMF selection.

[0241] Step 304: Select a target AMF that matches the terminal from the candidate AMF set.

[0242] In this step, the candidate AMF set includes one or more candidate AMFs that can be adapted to the terminal UE, but whether they can actually provide services to the UE needs to be screened to determine the best adapted target AMF.

[0243] In one embodiment, step 304 may specifically include: sending a broadcast message to each AMF in the candidate AMF set, the broadcast message carrying the terminal identifier and the NAS message, and determining the AMF in the candidate AMF set that first responds to the broadcast message as the target AMF matching the terminal.

[0244] In this embodiment, if the candidate AMF set contains multiple candidate AMFs, the RAN can broadcast a message to each candidate AMF, the broadcast message carries the UE identifier and the NAS message, and determines the AMF that first responds to the broadcast message among the candidate AMFs as the target AMF that can serve the UE. After successfully establishing a connection with the target AMF, the target AMF information is stored in the local UE context.

[0245] In one embodiment, in a scenario where each candidate AMF in the candidate AMF set is configured with a priority, step 304 may further specifically include: sending a first message to each AMF in the candidate AMF set in order from high to low according to the priority of each AMF in the candidate AMF set, the first message carrying a terminal identifier and / or a NAS message. The first AMF that is determined to be reachable is determined as the target AMF that matches the terminal. Alternatively, the first AMF that responds to the NAS message is determined as the target AMF that matches the terminal.

[0246] In this embodiment, if each candidate AMF in the candidate AMF set is configured with a priority, the RAN may send a first message to each AMF in the candidate AMF set in order from high to low according to the priority of each AMF in the candidate AMF list. Here, the first message is the first message communicated between the RAN and the target AMF. The first message may be a connection establishment message or an interface establishment message. The communication process may include two situations, the first is to complete the establishment and NAS message response in one time, and the second is to complete it in two times.

[0247] For the first case, for example, RAN can send a first message carrying the terminal identifier in order from high to low according to the priority of each AMF in the candidate AMF list, and the first message carries the terminal identifier and the NAS message. At this time, the first AMF that is determined to be reachable can be determined as the target AMF.

[0248] For the second case, RAN can send the first message carrying the terminal identifier in order from high to low according to the priority of each AMF in the candidate AMF list, and the first message carries the terminal identifier. Then, for the candidate AMGs determined to establish a connection, NAS messages are sent in order from high to low according to the priority, and the first AMF that responds to the NAS message can be determined as the target AMF matching the terminal.

[0249] Step 305: After successfully establishing a link with the target AMF, the target AMF and the uplink route related to the target AMF are stored in the terminal context.

[0250] In this step, after successfully establishing a link with the target AMF, the RAN may store the target AMF information and the uplink route related to the target AMF in the local UE context for subsequent use.

[0251] The above-mentioned AMF selection method determines the execution of AMF selection by RAN according to the information carried by the UE in the RRC message, and then RAN determines the AMF serving the UE according to the UE information (such as access RAT type, UE location information), UE capabilities and service requirements (such as delay tolerance indication, emergency services) and / or pre-configured AMF auxiliary information, establishes a route for uplink signaling transmission, and realizes the requirement of on-demand connection of interfaces under the RAN service-oriented architecture, thereby improving the flexibility of selecting the signaling transmission path.

[0252] Specifically, the RAN determines that the target NF of the NAS signaling is the AMF based on one or more of the UE identity carried in the RRC message, the core network NF type indication, and the information related to the matching NAS message distribution NF. The RAN determines the UE auxiliary information or the capability requirements for the AMF based on the UE information (such as the access RAT type, UE location information), UE capabilities and service requirements (such as delay tolerance indication, emergency services), and provides it to the core network NRF or NWDAF to screen the AMF. The RAN determines the list of candidate AMFs based on the UE identity, UE information, UE capabilities and service requirements, the local UE context, and the AMF auxiliary information. Then the RAN determines the target AMF based on the list of candidate AMFs by polling or broadcasting. Finally, the RAN stores the selected AMF information and the uplink route related to the AMF in the UE context.

[0253] like Figure 4 As shown, the embodiment of the present application provides an AMF selection method, which can be applied to Figure 1 In the application scenario of the 5G system structure shown in FIG. Figure 1 The core network shown is executed to meet the demand for on-demand connection of interfaces under the RAN service-oriented architecture and improve the flexibility of selecting signaling transmission paths. The method includes the following steps:

[0254] Step 401: Receive an NF discovery request sent by a wireless access network RAN, where the NF discovery request carries a candidate AMF set matching the terminal and the terminal's demand information for AMF, wherein the candidate AMF set is determined by the RAN based on the terminal identifier and / or the terminal context locally stored in the RAN, and the demand information is determined by the RAN based on one or more of the terminal location information, the terminal access type, the slice information requested by the terminal, the terminal's capabilities and service requirements.

[0255] In this step, the assistance of NRF can be used to assist RAN in selecting AMF. RAN can select and determine the target NRF that provides services to the terminal based on the selected PLMN / NPN information carried in the RRC message in step 301. Then RAN can determine the preferred AMF (i.e., the set of candidate AMFs available to the terminal) based on one or more of the information related to AMF in the RRC message (e.g., UE identity) and the locally stored UE context (AMF identity, AMF routing information). RAN determines the UE assistance information, where the UE assistance information is the terminal UE's demand information for AMF, including but not limited to: UE information such as UE location information, UE access type, and one or more of the UE capabilities and service requirements such as requested slice information, support for multiple access indications, and delay tolerance indications. Then, RAN sends a NF discovery request to the target NRF, and the request carries one or more of the preferred AMF and UE assistance information. The target NRF receives the NF discovery request sent by RAN.

[0256] Step 402: In response to the NF discovery request, determine the candidate AMF set available to the terminal based on the candidate AMF set, demand information, and the current status and load information of each AMF in the core network.

[0257] In this step, after the core network receives the NF discovery request sent by the RAN, it responds to the NF discovery request and determines one or more alternative AMF instances based on the preferred AMF provided by the RAN, the capability requirements for the AMF, and the current status of the AMF.

[0258] In one embodiment, step 402 may specifically include: in response to the NF discovery request, determining the set of candidate AMFs available to the terminal through the target NRF in the core network that provides services to the terminal based on the candidate AMF set, demand information, and the current status and load information of each AMF in the core network, wherein the target NRF is determined by the RAN based on the mobile network identification code selected by the terminal.

[0259] In this embodiment, in the scenario where AMF is selected with the assistance of NRF, the target NRF selected by the terminal in the core network can determine one or more candidate AMF instances based on the preferred AMF provided by RAN, the capability requirements for AMF, and the current state of AMF, and notify RAN in the form of an NF discovery request response message. The NF discovery request response message carries the information of the selected candidate AMF identifier, the candidate AMF address identifier, the AMF Set to which it belongs, and so on. In this way, the entire determination process of the candidate AMF set can be implemented by utilizing the functions of NRF in the core network, which not only saves RAN resources, but also improves the resource utilization of the core network and improves efficiency.

[0260] In one embodiment, step 402 may specifically include: in response to the NF discovery request, the target NRF providing services to the terminal sends a data analysis request to the network data analysis function NWDAF in the core network, the data analysis request carries the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set, and the demand information, wherein the target NRF is determined by the RAN based on the mobile network identification code selected by the terminal. Receive the second matching degree between each AMF in the candidate AMF set and the terminal returned by the NWDAF, wherein the second matching degree is determined by the NWDAF based on the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set, and the demand information. The target NRF determines the candidate AMF set based on the second matching degree.

[0261] In this embodiment, the NWDAF in the core network can also be used to assist the NRF in selecting AMF. After the RAN sends an NF discovery request to the target NRF in the core network, the target NRF can send a data analysis request to the NWDAF in the core network, which carries RAN configuration information (such as RAN location), UE auxiliary information (i.e., UE's demand information for AMF) and each AMF configuration information in the candidate AMF set. The data analysis request is used to instruct the NWDAF to analyze the second matching degree between each AMF and the UE according to the preset resource usage model of the RAN and AMF. Then the NWDAF returns the second matching degree analysis result between the AMF and the UE to the target NRF through the data analysis request response message. The target NRF determines the candidate AMF set based on the second matching degree analysis result between the AMF and the UE, and sends the candidate AMF information such as the candidate AMF identifier, the candidate AMF address identifier, and the AMFSet to which it belongs in the candidate AMF set to the RAN through the NF discovery request response message. In this way, the target NRF seeks assistance from other functions in the core network, fully utilizes the existing network resources in the core network, and improves the efficiency of AMF selection.

[0262] Step 403: Send the candidate AMF set information to the RAN.

[0263] In this step, the target NRF notifies the RAN. Sends a NF discovery request response message to the RNA, and the response message carries the selected candidate AMF identifier, candidate AMF address identifier, AMF Set and other candidate AMF information. In this way, the entire determination process of the candidate AMF set can be implemented using the functions of the NRF of the core network, which not only saves RAN resources, but also improves the resource utilization of the core network and improves efficiency.

[0264] In one embodiment, the method further includes: the target NRF receives a registration request sent by the RAN, the registration request carrying the configuration information of the RAN and the AMF assistance indication. In response to the AMF assistance indication, the target NRF determines the optional AMF information set and the corresponding AMF matching rule set according to the configuration information of the RAN and the current status and load information of each AMF in the core network. The target NRF returns a response message to the RAN, wherein the response message carries the optional AMF information set and the corresponding AMF matching rule set.

[0265] In this embodiment, when registering with the RAN, the RAN may obtain the AMF auxiliary information from the network storage function NRF of the core network. Specifically, the process may be as follows:

[0266] After the RAN node is powered on or the parameters are modified, a RAN registration service request is initiated to the NRF of the core network. The request carries the configuration information of the RAN and the request for AMF assistance indication, wherein the configuration information of the RAN (which may be a RAN profile, a RAN configuration file) includes but is not limited to one or more of the RAN node identifier, PLMN / NPN identifier, RAT type, geographic location information, supported TA list, slice information, and capability information (such as communication, perception). The target NRF determines a set of optional AMF information sets available to the terminal UE and a set of related AMF matching rules based on the RAN configuration information, the current capability status and load information of each AMF in the core network. Among them, the optional AMF information set includes but is not limited to: each optional AMF identifier, AMF address identifier, AMF Set information and other contents, which can be in the form of a list. AMF Set refers to an AMF grouping set. In actual scenarios, all AMFs in the core network can be divided into several groups, each of which is called an AMF Set. AMF matching rules may include but are not limited to: the matching degree of each AMF based on the RAT type, the matching degree of each AMF based on geographical proximity and distance, and other information.

[0267] Then the target NRF responds to the RAN registration service request, carrying the generated optional AMF information set and AMF matching rule set in the response message. RAN stores the received optional AMF information set and AMF matching rule set in the AMF auxiliary information. In this way, the network resources of the NRF in the core network are fully utilized, the resources of the RAN itself are saved, and the resource utilization rate is improved.

[0268] In one embodiment, the method further includes: the target NRF receives an AMF assisted update request sent by the RAN, and / or a subscription message of the RAN to an AMF assisted information update event. The target NRF determines the updated optional AMF information set and / or the updated AMF matching rule set based on the configuration information of the RAN, the optional AMF set, and the updated status and load information of each AMF in the core network. In response to the AMF assisted update request, the target NRF returns the AMF update information to the RAN, and the AMF update information includes the updated optional AMF information set and / or the corresponding updated AMF matching rule set. And / or, in response to the subscription message, the target NRF notifies the RAN of the AMF update information, and the AMF update information includes the updated optional AMF information set and the corresponding updated AMF matching rule set.

[0269] In this embodiment, in order to maintain the timeliness of AMF auxiliary information, the core network NRF can provide an AMF auxiliary information update service. Specifically, in the process of RAN registering with NRF to obtain AMF auxiliary information, the registration service request sent by the RAN can carry a request to receive an AMF auxiliary update, or the RAN can subscribe to the AMF auxiliary information update event to the NRF service, and carry the RAN identifier, the indication of receiving AMF auxiliary information, and other information in the subscription message. The target NRF of the core network monitors the AMF in the optional AMF information set or selects a new optional AMF according to the request to receive an AMF auxiliary update in the RAN registration request, or the AMF auxiliary information update event subscribed by the RAN.

[0270] During this process, if the selected AMF configuration information (such as the terminal adapter TA identifier) ​​in the optional AMF information set changes, or the AMF state changes (such as overload, deregistration, connection failure), the NRF updates the optional AMF information set and determines the corresponding updated AMF matching rule set. If a new AMF is online, the NRF can update the new optional AMF to the optional AMF information set and determine the corresponding updated AMF matching rule set. Then the NRF notifies the RAN, and the notification message carries the updated optional AMF information set and / or the updated AMF matching rule set. The RAN updates the local AMF auxiliary information based on the received updated optional AMF information set and the updated AMF matching rule set. In this way, the NRF update function of the core network is used to realize the update of AMF auxiliary information and maintain the timeliness of the AMF auxiliary information.

[0271] The above-mentioned AMF selection method generates AMF auxiliary information according to the requirements of RAN through the NRF of the core network, and updates the AMF auxiliary information. Optionally, NRF can analyze the matching degree of AMF with the help of NWDAF to determine the target AMF. In this way, the core network provides auxiliary information to RAN to assist RAN in selecting AMF, and with the assistance of core network functions, dynamically selects the service AMF for UE and establishes an uplink signaling transmission path. It meets the requirements of the service-oriented architecture for establishing connections on demand, flexibly scheduling and managing network resources, and can adapt to various RAN and AMF deployment scenarios. Make full use of the existing network resources in the core network to improve the efficiency and flexibility of AMF selection.

[0272] like Figure 5 As shown, the present application embodiment provides a signaling interaction flow diagram of an AMF auxiliary information generation method, which can be applied to Figure 1 In the application scenario of the 5G system structure shown in FIG. 1 , AMF auxiliary information is provided for the AMF selection method of the embodiment of the present application, and is provided by Figure 1 The RAN and NRF shown in the figure interact with each other. Based on the above embodiment, this embodiment takes the process of obtaining AMF auxiliary information from NRF when registering with RAN as an example to describe in detail the signaling interaction process between various network elements. The method includes the following steps:

[0273] Step 501: After the RAN node is powered on or its parameters are modified, a RAN registration service request is initiated to the NRF. The request carries RAN node identifier, PLMN / NPN identifier, RAT type, geographic location information, supported TA list, slice information, capability information (such as communication, perception) and other RAN configuration information (i.e., RAN profile), as well as a request for AMF assistance information indication.

[0274] Step 502: The NRF generates a set of available AMFs and related AMF matching rules (for example, the matching degree of each AMF based on RAT type, the matching degree of each AMF based on geographical proximity) according to the RAN configuration information, the capabilities of each AMF and the load conditions.

[0275] Step 503: The NRF responds to the RAN registration service request and carries the generated optional AMF list and AMF matching rule set in the response message.

[0276] Step 504: RAN stores the AMF assistance information.

[0277] The details of the above method can refer to the description of the corresponding method embodiment in the above embodiment. The implementation principle and technical effect are similar, and this embodiment will not be repeated here.

[0278] like Figure 6 As shown, the present application embodiment provides a signaling interaction flow diagram of an AMF auxiliary information update method, which can be applied to Figure 1 In the application scenario of the 5G system structure shown in FIG. 1 , the AMF auxiliary information is provided for the AMF selection method of the embodiment of the present application, and is provided by Figure 1 The RAN and NRF shown in the figure interact with each other. Based on the above embodiment, this embodiment takes the process of RAN obtaining updated AMF auxiliary information from NRF as an example to describe in detail the signaling interaction process between each network element. The method includes the following steps:

[0279] Step 601: RAN registers and obtains AMF auxiliary information. The registration service request sent by the RAN may carry an indication of receiving AMF auxiliary information update.

[0280] In this step, specifically, 1a. RAN subscribes to the AMF auxiliary information update event through the NRF service. The subscription message carries information such as the RAN identifier and the indication of receiving the AMF auxiliary information.

[0281] Step 602: The NRF monitors the AMF status in the selected AMF list or selects a new AMF according to the received AMF assistance information update indication in the RAN registration request or the AMF assistance information update event subscribed by the RAN.

[0282] Step 603: When the selected AMF configuration information (e.g., TA identifier) ​​changes, or the AMF status changes (e.g., overload, deregistration, connection failure), the NRF updates the optional AMF list and the corresponding AMF matching rules.

[0283] Step 604: When the NRF monitors that a new AMF is online, the NRF updates the optional AMF list and the corresponding AMF matching rules.

[0284] There is no limitation on the order of step 603 and step 604 , and in actual scenarios, the two steps can be performed simultaneously or separately.

[0285] Step 605: NRF notifies RAN, carrying the updated AMF assistance information, that is, the updated optional AMF list and AMF matching rule set.

[0286] Step 606: RAN updates local AMF assistance information.

[0287] The details of the above method can refer to the description of the corresponding method embodiment in the above embodiment. The implementation principle and technical effect are similar, and this embodiment will not be repeated here.

[0288] like Figure 7 As shown, the present application embodiment provides a signaling interaction flow diagram of an AMF selection method, which can be applied to Figure 1 In the application scenario of the 5G system structure shown in FIG. Figure 1 The UE, RAN, NRF, and candidate AMF shown in the figure are interactively executed. In this embodiment, based on the above embodiment, it is assumed that the device selected AMF set includes candidate AMF1 and candidate AMF2. Taking the process in which RAN selects the target AMF by polling according to UE information and AMF auxiliary information as an example, the signaling interaction process between each network element is described in detail. The method includes the following steps:

[0289] Step 701: The UE sends an RRC message carrying a NAS message (e.g., a registration message, a service request message) to the RAN. The RAN determines that the target NF type of the NAS signaling is AMF based on one or more information such as the UE identity, the core network NF type indication, and the matching locally configured NAS message distribution method carried in the RRC message, and then the RAN performs the AMF selection process.

[0290] Step 702: The RAN screens and establishes a prioritized list of candidate AMFs based on one or more of the UE information (e.g., UE identity, UE location information, UE access type), UE capabilities and service requirements, locally stored UE context (e.g., AMF identity, AMF routing information), and AMF assistance information. The screening and priority principles of the candidate AMFs may include:

[0291] The first AMF configuration parsed from the UE identity (e.g. 5G-S-TMSI or 5G-GUTI) has a higher priority, assuming the first priority.

[0292] Determine, based on the locally stored UE context, that the second AMF for which routing information already exists is configured as a higher priority, assuming that the second priority is configured, and the second priority is less than or equal to the first priority.

[0293] In the optional AMF information set, the third AMF that belongs to the same AMF Set as the first AMF parsing the UE identity (e.g. GUAMI) or the same AMF Set as the second AMF with existing routing information is configured as a higher priority. Assuming that the priority is configured as security, the third priority can be lower than the second priority.

[0294] The first matching degree between the fourth AMF and the terminal UE can be evaluated based on the UE location information, UE access type, UE capability and service requirements, and the information in the AMF matching rule set. The higher the first matching degree, the higher the priority of the fourth AMF.

[0295] Step 703: RAN establishes connections and sends NAS messages in order according to the priorities of the candidate AMFs in the candidate AMF list, from high to low, until the first AMF that is determined to be reachable is the target AMF. After the connection is successfully established, the AMF information is stored in the UE context.

[0296] Assuming that the device selection AMF list includes AMF1 and AMF2, wherein the priority of AMF1 is greater than the priority of AMF2, the following steps may be included:

[0297] 3a: RAN requests AMF service from AMF1, and the request carries UE identity and NAS message.

[0298] 3b: RAN requests AMF service from AMF2, and the request carries UE identity and NAS message.

[0299] It will be assumed that AMF1 is the first reachable AMF, then AMF1 can be determined as the target AMF that can provide services to the UE.

[0300] For details of the above AMF selection method, please refer to the description of the corresponding method embodiment in the above embodiment. Its implementation principle and technical effect are similar, and this embodiment will not be repeated here.

[0301] like Figure 8 As shown, the present application embodiment provides a signaling interaction flow diagram of an AMF selection method, which can be applied to Figure 1 In the application scenario of the 5G system structure shown in FIG. Figure 1 The UE, RAN, NRF, and candidate AMF shown in the figure are interactively executed. In this embodiment, based on the above embodiment, it is assumed that the candidate AMF set includes candidate AMF1 and candidate AMF2. Taking the process of RAN selecting the target AMF from the candidate AMF set by broadcasting a message as an example, the signaling interaction process between each network element is described in detail. The method includes the following steps:

[0302] Step 801: The UE sends an RRC message carrying a NAS message (e.g., a registration message, a service request message) to the RAN. The RAN determines that the target NF type of the NAS signaling is AMF based on one or more information such as the UE identity, the core network NF type indication, and the matching locally configured NAS message distribution method carried in the RRC message, and then the RAN performs the AMF selection process.

[0303] Step 802: The RAN screens and determines the candidate AMF list based on one or more of the UE information, UE capabilities and service requirements, locally stored UE context, and AMF assistance information. The screening principles for the candidate AMF may include:

[0304] The first AMF that matches the UE parsed from the UE identifier (e.g., 5G-S-TMSI or 5G-GUTI) may be included in the candidate AMF list.

[0305] The second AMF for which routing information is already determined based on the locally stored UE context may enter the list of candidate AMFs.

[0306] In the optional AMF information set, the third AMF that belongs to the same AMF Set as the first AMF parsed by the UE identity (e.g. GUAMI) or the same AMF Set as the second AMF with existing routing information can be included in the candidate AMF list.

[0307] The fourth AMF in the optional AMF information set that matches all or part of the UE location information, UE access type, UE capabilities and service requirements is added to the candidate AMF list.

[0308] Step 803: RAN broadcasts a message to each candidate AMF, carrying the UE identity and NAS message. The AMF that responds first is the serving AMF of the UE. After the connection is successfully established, the AMF information is stored in the UE context.

[0309] For details of the above AMF selection method, please refer to the description of the corresponding method embodiment in the above embodiment. Its implementation principle and technical effect are similar, and this embodiment will not be repeated here.

[0310] like Fig. 9 As shown, the present application embodiment provides a signaling interaction flow diagram of an AMF selection method, which can be applied to Figure 1 In the application scenario of the 5G system structure shown in FIG. Figure 1 The UE, RAN, NRF, and alternative AMF shown in the figure are interactively executed. Based on the above embodiment, this embodiment takes the RAN-assisted NRF selection AMF scenario as an example to describe in detail the signaling interaction process between each network element. The method includes the following steps:

[0311] Step 901: The UE sends an RRC message carrying a NAS message (e.g., a registration message, a service request message) to the RAN. The RAN determines that the target NF type of the NAS signaling is AMF based on one or more information such as the UE identity, the core network NF type indication, and the matching locally configured NAS message distribution method carried in the RRC message, and then the RAN performs the AMF selection process.

[0312] Step 902: The RAN selects and determines the target NRF serving the UE according to the selected PLMN / NPN information carried in the RRC message.

[0313] Step 903: RAN determines the preferred AMF based on one or more of the AMF-related information in the RRC message (e.g., UE identifier) ​​and the locally stored UE context (AMF identifier, AMF routing information). RAN determines the UE auxiliary information (UE information such as UE location information, UE access type, requested slice information, support for multiple access indications, delay tolerance indication, and other UE capabilities and service requirements). Then, RAN sends a NF discovery request (Nnrf_NFDiscovery_Request) to NRF, which carries one or more of the preferred AMF and UE auxiliary information. The UE auxiliary information here may also be the UE capability requirement information for AMF.

[0314] Step 904: NRF determines an AMF instance based on the preferred AMF provided by RAN, the capability requirements for AMF, and the current AMF status, and sends an NF discovery request response message (Nnrf_NFDiscovery_Response) to RAN. The NF discovery request response message carries the selected AMF identifier, AMF address identifier, AMF Set and other candidate AMF information. Here, the candidate AMF can be one.

[0315] Step 905: RAN establishes a route with the alternative AMF service and sends the UE identity and NAS message. After the connection is successful, the alternative AMF information is stored in the UE context.

[0316] For details of the above AMF selection method, please refer to the description of the corresponding method embodiment in the above embodiment. Its implementation principle and technical effect are similar, and this embodiment will not be repeated here.

[0317] like Fig.10 As shown, the present application embodiment provides a signaling interaction flow diagram of an AMF selection method, which can be applied to Figure 1 In the application scenario of the 5G system structure shown in FIG. Figure 1The UE, RAN, NRF, NWDAF, and alternative AMF shown in the figure are interactively executed. Based on the above embodiment, this embodiment takes the NWDAF assisting NRF to select AMF scenario as an example to describe in detail the signaling interaction process between each network element. The method includes the following steps:

[0318] Step 1001: The UE sends an RRC message carrying a NAS message (e.g., a registration message, a service request message) to the RAN. The RAN determines that the target NF type of the NAS signaling is AMF based on one or more information such as the UE identity, the core network NF type indication, and the matching locally configured NAS message distribution method carried in the RRC message, and then the RAN performs the AMF selection process.

[0319] Step 1002: The RAN selects and determines a target NRF serving the UE according to the selected PLMN / NPN information carried in the RRC message.

[0320] Step 1003: RAN determines the preferred AMF based on one or more of the information related to AMF in the RRC message (e.g., UE identifier) ​​and the locally stored UE context (e.g., AMF identifier, AMF routing information). RAN determines the UE auxiliary information based on UE information such as UE location information, UE access type, requested slice information, support for multiple access indications, delay tolerance indications and other UE capabilities and service requirements. Then, RAN sends an NF discovery request (Nnrf_NFDiscovery_Request) to NRF, which carries one or more of the preferred AMF and UE auxiliary information. The UE auxiliary information here can be the UE capability requirement information for AMF.

[0321] Step 1004: NRF sends a data analysis request (Nnwdaf_AnalyticInfo_Request) to NWDAF, and the data analysis request carries RAN information (such as RAN location), UE auxiliary information and AMF configuration information.

[0322] Step 1005: NWDAF analyzes the matching degree between each AMF and UE according to the resource usage model of RAN and AMF.

[0323] Step 1006: NWDAF sends the AMF matching analysis result to NRF via a data analysis request response message (Nnwdaf_AnalyticInfo_Response).

[0324] Step 1007: NRF determines the candidate AMF according to the AMF matching analysis result, and sends the candidate AMF information such as the AMF identifier, AMF address identifier, and AMF Set of the candidate AMF to RAN through the NF discovery request response message (Nnrf_NFDiscovery_Response). Here, the candidate AMF can be one.

[0325] Step 1008: RAN establishes a route with the selected AMF and sends the UE identity and NAS message. After the connection is successful, the candidate AMF information is stored in the UE context.

[0326] For details of the above AMF selection method, please refer to the description of the corresponding method embodiment in the above embodiment. Its implementation principle and technical effect are similar, and this embodiment will not be repeated here.

[0327] like Fig.11 As shown, the embodiment of the present application provides an AMF selection device, which can be as follows Figure 1 The radio access network RAN ​​in the 5G system structure shown in the figure satisfies the demand for on-demand connection of interfaces under the RAN service-oriented architecture and improves the flexibility of selecting signaling transmission paths. The device includes: a memory 1120, a transceiver 1110, and a processor 1100. On the PCF side, the transceiver 1110 is used to receive and send data under the control of the processor 1100.

[0328] Among them, Fig.11 In the embodiment, the bus architecture may include any number of interconnected buses and bridges, specifically one or more processors 1100 represented by processor 1100 and various circuits of memory 1120 represented by memory 1120 are linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 1110 may be a plurality of components, namely, a transmitter and a receiver, providing a unit for communicating with various other devices on a transmission medium, which transmission medium includes wireless channels, wired channels, optical cables, and other transmission media. For different user devices, the user interface 1130 may also be an interface capable of externally and internally connecting required devices, and the connected devices include but are not limited to a keypad, a display, a speaker, a microphone, a joystick, and the like.

[0329] The processor 1100 is responsible for managing the bus architecture and general processing, and the memory 1120 can store data used by the processor 1100 when performing operations.

[0330] Optionally, the processor 1100 may be a CPU (central processing unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array) or a CPLD (Complex Programmable Logic Device), and the processor 1100 may also adopt a multi-core architecture.

[0331] The processor 1100 is used to execute any method provided in the embodiments of the present application according to the obtained executable instructions by calling the computer program stored in the memory 1120. The processor 1100 and the memory 1120 can also be arranged physically separately.

[0332] In this embodiment, the memory 1120 is used to store a computer program. The transceiver 1110 is used to send and receive data under the control of the processor 1100. The processor 1100 is used to read the computer program in the memory 1120 and perform the following operations:

[0333] Receive the radio resource management RRC message sent by the terminal, which carries the non-access layer NAS message and the terminal's attribute information. Determine the target NF type of the core network specified by the NAS message based on the terminal's attribute information. When the target NF type is the access and mobility management function AMF, determine the candidate AMF set available to the terminal based on the terminal's attribute information. Select the target AMF that matches the terminal from the candidate AMF set.

[0334] In one embodiment, the attribute information of the terminal includes: one or more of an identifier of the terminal, an indication of a core network NF type, and a NAS message distribution mode. Determining the target NF type specified by the NAS message according to the attribute information of the terminal includes: determining the target NF type of the core network specified by the NAS message according to one or more of an identifier of the terminal, an indication of a core network NF type, and a NAS message distribution mode.

[0335] In one embodiment, determining the candidate AMF set available to the terminal according to the attribute information of the terminal includes: obtaining AMF assistance information locally maintained by the radio access network RAN. Determining the candidate AMF set available to the terminal according to the attribute information and / or AMF assistance information of the terminal.

[0336] In one embodiment, the attribute information of the terminal includes: one or more of the terminal identification, terminal location information, terminal access type, terminal capabilities and service requirements. The AMF auxiliary information includes an optional AMF information set. According to the attribute information and / or AMF auxiliary information of the terminal, the alternative AMF set available to the terminal is determined, including: parsing the first AMF matching the terminal according to the terminal identification, and adding the first AMF to the alternative AMF set. And / or, determining the second AMF with existing routing information according to the context information of the terminal stored locally in the RAN, and adding the second AMF to the alternative AMF set. And / or, adding the third AMF in the optional AMF information set that belongs to the same AMF group set as the first AMF or the same AMF group set as the second AMF to the alternative AMF set. And / or, adding the fourth AMF in the optional AMF information set that matches one or more of the terminal location information, terminal access type, terminal capabilities and service requirements to the alternative AMF set.

[0337] In one embodiment, determining the candidate AMF set available to the terminal according to the terminal attribute information and / or AMF auxiliary information also includes: configuring the priority of each AMF in the candidate AMF set, and the priority configuration rule includes: configuring the first AMF as the first priority with the highest level. And / or, configuring the second AMF as the second priority, the second priority is less than or equal to the first priority. And / or, configuring the third AMF as the third priority, the third priority is less than the second priority.

[0338] In one embodiment, the AMF auxiliary information also includes an AMF matching rule set. According to the attribute information and / or AMF auxiliary information of the terminal, the alternative AMF set available to the terminal is determined, and it also includes: according to the AMF matching rule set, the fourth AMF in the optional AMF information set that matches one or more of the terminal location information, terminal access type, terminal capabilities and business requirements is added to the alternative AMF set. And / or, according to the terminal location information, terminal access type, terminal capabilities and business requirements, the first matching degree of each AMF in the fourth AMF and the terminal is evaluated according to the AMF matching rule set. The fourth priority of each fourth AMF is configured according to the first matching degree, wherein the first matching degree is positively correlated with the fourth priority of the corresponding fourth AMF.

[0339] In one embodiment, before obtaining the AMF auxiliary information maintained locally in the radio access network RAN, a step of generating AMF auxiliary information is also included, including: sending a registration request to the network repository function NRF of the core network, the registration request carrying the configuration information of the RAN and the indication of requesting AMF assistance. Receive a response message returned by the NRF, the response message carrying an optional AMF information set and a corresponding AMF matching rule set, wherein the optional AMF information set and the AMF matching rule set are determined by the NRF based on the configuration information of the RAN and the current status and load information of each AMF in the core network. Generate AMF auxiliary information based on the optional AMF information set and the AMF matching rule set.

[0340] In one embodiment, the step of generating AMF auxiliary information also includes: sending an AMF auxiliary update request to the NRF, and / or subscribing to the AMF auxiliary information update event to the NRF. Receive the AMF update information returned by the NRF, the AMF update information includes the updated optional AMF information set and / or the corresponding updated AMF matching rule set. The updated optional AMF information set and / or the updated AMF matching rule set are determined by the NRF based on the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network. According to the updated optional AMF information set and the updated AMF matching rule set, update the AMF auxiliary information stored locally in the RAN.

[0341] In one embodiment, the attribute information of the terminal includes: terminal identification, terminal location information, terminal access type, slice information requested by the terminal, terminal capabilities and service requirements, terminal context stored locally in the RAN, and one or more of the mobile network identification code selected by the terminal. Determine the set of candidate AMFs available to the terminal based on the attribute information of the terminal, and also include: determining the target NRF that provides services to the terminal based on the mobile network identification code selected by the terminal. Determine the set of candidate AMFs available to the terminal based on the terminal identification and / or terminal context. Determine the terminal's demand information for AMF based on one or more of the terminal location information, terminal access type, terminal capabilities and service requirements. Send an NF discovery request to the target NRF, the NF discovery request carries the candidate AMF set and requirement information, and the NF discovery request is used to instruct the target NRF to return the set of candidate AMFs available to the terminal. Receive the set of candidate AMFs available to the terminal returned by the target NRF.

[0342] In one embodiment, the candidate AMF set is determined by the target NRF based on the candidate AMF set, demand information, and the current status and load information of each AMF in the core network.

[0343] In one embodiment, the candidate AMF set is determined by the target NRF based on the second matching degree between each AMF in the candidate AMF set and the terminal, and the second matching degree is determined by the network data analysis function NWDAF in the core network based on the configuration information of the radio access network RAN, the configuration information of each AMF in the candidate AMF set and the demand information.

[0344] In one embodiment, selecting a target AMF that matches the terminal from a candidate AMF set also includes: sending a first message to each AMF in the candidate AMF set in order from high to low according to the priority of each AMF in the candidate AMF set, the first message carrying a terminal identifier and / or a NAS message. The first AMF that is determined to be reachable is determined as the target AMF that matches the terminal. Alternatively, the first AMF that responds to the NAS message is determined as the target AMF that matches the terminal.

[0345] In one embodiment, a target AMF matching the terminal is selected from a candidate AMF set, including: sending a broadcast message to each AMF in the candidate AMF set, the broadcast message carrying a terminal identifier and a NAS message, and determining the AMF in the candidate AMF set that first responds to the broadcast message as the target AMF matching the terminal.

[0346] In one embodiment, after selecting a target AMF matching the terminal from a set of candidate AMFs, it also includes: after successfully establishing a link with the target AMF, storing the target AMF and the uplink route related to the target AMF in the terminal context.

[0347] It should be noted here that the above-mentioned device provided in the present application can implement all the method steps implemented by the corresponding method embodiment, and can achieve the same technical effect. The parts and beneficial effects of this embodiment that are the same as the method embodiment will not be described in detail here.

[0348] like Fig.12 As shown, the embodiment of the present application provides an AMF selection device, which can be as follows Figure 1 The core network in the 5G system structure shown in the figure can meet the demand for on-demand connection of interfaces under the RAN service-oriented architecture and improve the flexibility of selecting signaling transmission paths. The device includes: a memory 1220, a transceiver 1210, and a processor 1200. The transceiver 1210 is used to receive and send data under the control of the processor 1200.

[0349] exist Fig.12In the embodiment, the bus architecture may include any number of interconnected buses and bridges, specifically one or more processors 1200 represented by processor 1200 and various circuits of memory 1220 represented by memory 1220 are linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 1210 may be a plurality of components, namely, a transmitter and a receiver, providing a unit for communicating with various other devices on a transmission medium, which transmission medium may include a wireless channel, a wired channel, an optical cable, and other transmission media. The processor 1200 is responsible for managing the bus architecture and general processing, and the memory 1220 may store data used by the processor 1200 when performing operations.

[0350] The processor 1200 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or a complex programmable logic device (CPLD). The processor 1200 may also adopt a multi-core architecture.

[0351] In this embodiment, the memory 1220 is used to store a computer program. The transceiver 1210 is used to send and receive data under the control of the processor 1200. The processor 1200 is used to read the computer program in the memory 1220 and perform the following operations:

[0352] Receive the NF discovery request sent by the wireless access network RAN, which carries the candidate AMF set matching the terminal and the terminal's demand information for AMF, wherein the candidate AMF set is determined by the RAN based on the terminal identification and / or the terminal context stored locally in the RAN, and the demand information is determined by the RAN based on one or more of the terminal location information, terminal access type, slice information requested by the terminal, terminal capabilities and service requirements. In response to the NF discovery request, determine the candidate AMF set available to the terminal based on the candidate AMF set, demand information and the current status and load information of each AMF in the core network. Send the candidate AMF set information to the RAN.

[0353] In one embodiment, in response to an NF discovery request, a set of candidate AMFs available to the terminal is determined based on a set of candidate AMFs, demand information, and the current status and load information of each AMF in the core network, including: in response to an NF discovery request, a set of candidate AMFs available to the terminal is determined through a target NRF in the core network that provides services to the terminal based on a set of candidate AMFs, demand information, and the current status and load information of each AMF in the core network, wherein the target NRF is determined by the RAN based on a mobile network identification code selected by the terminal.

[0354] In one embodiment, in response to an NF discovery request, the candidate AMF set available to the terminal is determined based on the candidate AMF set, demand information, and the current status and load information of each AMF in the core network, including: in response to the NF discovery request, the target NRF providing services to the terminal sends a data analysis request to the network data analysis function NWDAF in the core network, and the data analysis request carries the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set, and the demand information, wherein the target NRF is determined by the RAN based on the mobile network identification code selected by the terminal. The second matching degree between each AMF in the candidate AMF set and the terminal is received from the NWDAF, wherein the second matching degree is determined by the NWDAF based on the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set, and the demand information. The target NRF determines the candidate AMF set based on the second matching degree.

[0355] In one embodiment, it also includes: the target NRF receives a registration request sent by the RAN, and the registration request carries the configuration information of the RAN and the AMF auxiliary indication. In response to the AMF auxiliary indication, the target NRF determines the optional AMF information set and the corresponding AMF matching rule set according to the configuration information of the RAN and the current status and load information of each AMF in the core network. The target NRF returns a response message to the RAN, wherein the response message carries the optional AMF information set and the corresponding AMF matching rule set.

[0356] In one embodiment, it also includes: the target NRF receives an AMF assisted update request sent by the RAN, and / or a subscription message of the RAN to an AMF assisted information update event. The target NRF determines the updated optional AMF information set and / or the updated AMF matching rule set based on the configuration information of the RAN, the optional AMF set, and the updated status and load information of each AMF in the core network. In response to the AMF assisted update request, the target NRF returns the AMF update information to the RAN, and the AMF update information includes the updated optional AMF information set and / or the corresponding updated AMF matching rule set. And / or, in response to the subscription message, the target NRF notifies the RAN of the AMF update information, and the AMF update information includes the updated optional AMF information set and the corresponding updated AMF matching rule set.

[0357] It should be noted here that the above-mentioned device provided in the present application can implement all the method steps implemented by the corresponding method embodiment, and can achieve the same technical effect. The parts and beneficial effects of this embodiment that are the same as the method embodiment will not be described in detail here.

[0358] like Fig.13 As shown, the embodiment of the present application provides an AMF selection device 1300, which can be as follows Figure 1 The wireless access network RAN ​​in the 5G system structure shown in the figure can meet the demand for on-demand connection of interfaces under the RAN service-oriented architecture and improve the flexibility of selecting signaling transmission paths. The device includes: a first receiving module 1301, a first determining module 1302, a second determining module 1303, and a selecting module 1304. The functional principles of each module are as follows:

[0359] The first receiving module 1301 is configured to receive a radio resource management RRC message sent by a terminal, where the RRC message carries a non-access stratum NAS message and attribute information of the terminal.

[0360] The first determination module 1302 is used to determine the target NF type of the core network specified by the NAS message according to the attribute information of the terminal.

[0361] The second determination module 1303 is used to determine a set of candidate AMFs available to the terminal according to the attribute information of the terminal when the target NF type is an access and mobility management function AMF.

[0362] The selection module 1304 is used to select a target AMF that matches the terminal from the candidate AMF set.

[0363] In one embodiment, the attribute information of the terminal includes: one or more of the terminal identifier, the core network NF type indication, and the NAS message distribution mode. The first determination module 1302 is used to determine the target NF type of the core network specified by the NAS message according to one or more of the terminal identifier, the core network NF type indication, and the NAS message distribution mode.

[0364] In one embodiment, the second determination module 1303 is used to obtain AMF assistance information locally maintained by the radio access network RAN ​​and determine a candidate AMF set available to the terminal according to the terminal attribute information and / or the AMF assistance information.

[0365] In one embodiment, the attribute information of the terminal includes: one or more of the terminal identification, terminal location information, terminal access type, terminal capabilities and business requirements. The AMF auxiliary information includes an optional AMF information set. The second determination module 1303 is used to parse out the first AMF that matches the terminal according to the terminal identification, and add the first AMF to the alternative AMF set. And / or, determine the second AMF with existing routing information according to the context information of the terminal stored locally in the RAN, and add the second AMF to the alternative AMF set. And / or, add the third AMF in the optional AMF information set that belongs to the same AMF group set as the first AMF or the same AMF group set as the second AMF to the alternative AMF set. And / or, add the fourth AMF in the optional AMF information set that matches one or more of the terminal location information, terminal access type, terminal capabilities and business requirements to the alternative AMF set.

[0366] In one embodiment, the second determination module 1303 is used to configure a priority for each AMF in the candidate AMF set, and the priority configuration rule includes: configuring the first AMF as the first priority with the highest level. And / or, configuring the second AMF as the second priority, the second priority is less than or equal to the first priority. And / or, configuring the third AMF as the third priority, the third priority is less than the second priority.

[0367] In one embodiment, the AMF auxiliary information also includes an AMF matching rule set. The second determination module 1303 is used to add the fourth AMF in the optional AMF information set that matches one or more of the terminal location information, terminal access type, terminal capabilities and business requirements to the alternative AMF set according to the AMF matching rule set. And / or, based on the terminal location information, terminal access type, terminal capabilities and business requirements, the first matching degree between each AMF in the fourth AMF and the terminal is evaluated according to the AMF matching rule set. The fourth priority of each fourth AMF is configured according to the first matching degree, wherein the first matching degree is positively correlated with the fourth priority of the corresponding fourth AMF.

[0368] In one embodiment, it also includes: a first auxiliary module, which is used to send a registration request to the network repository function NRF of the core network before obtaining the AMF auxiliary information maintained locally by the radio access network RAN, and the registration request carries the configuration information of the RAN and the indication of requesting AMF assistance. Receive a response message returned by the NRF, and the response message carries an optional AMF information set and a corresponding AMF matching rule set, wherein the optional AMF information set and the AMF matching rule set are determined by the NRF according to the configuration information of the RAN and the current status and load information of each AMF in the core network. Generate AMF auxiliary information according to the optional AMF information set and the AMF matching rule set.

[0369] In one embodiment, it also includes: a first update module, which is used to send an AMF auxiliary update request to the NRF, and / or subscribe to the AMF auxiliary information update event to the NRF. And receive the AMF update information returned by the NRF, the AMF update information includes the updated optional AMF information set and / or the corresponding updated AMF matching rule set. The updated optional AMF information set and / or the updated AMF matching rule set are determined by the NRF based on the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network. According to the updated optional AMF information set and the updated AMF matching rule set, the AMF auxiliary information stored locally in the RAN is updated.

[0370] In one embodiment, the attribute information of the terminal includes: terminal identification, terminal location information, terminal access type, slice information requested by the terminal, terminal capabilities and service requirements, terminal context stored locally in the RAN, and one or more of the mobile network identification code selected by the terminal. The second determination module 1303 is also used to determine the target NRF that provides services to the terminal based on the mobile network identification code selected by the terminal. Determine the set of candidate AMFs available to the terminal based on the terminal identification and / or terminal context. Determine the terminal's demand information for AMF based on one or more of the terminal location information, terminal access type, terminal capabilities and service requirements. Send an NF discovery request to the target NRF, the NF discovery request carries a candidate AMF set and requirement information, and the NF discovery request is used to instruct the target NRF to return a set of alternative AMFs available to the terminal. Receive the set of alternative AMFs available to the terminal returned by the target NRF.

[0371] In one embodiment, the candidate AMF set is determined by the target NRF based on the candidate AMF set, demand information, and the current status and load information of each AMF in the core network.

[0372] In one embodiment, the candidate AMF set is determined by the target NRF based on the second matching degree between each AMF in the candidate AMF set and the terminal, and the second matching degree is determined by the network data analysis function NWDAF in the core network based on the configuration information of the radio access network RAN, the configuration information of each AMF in the candidate AMF set and the demand information.

[0373] In one embodiment, the selection module 1304 is used to send a first message to each AMF in the candidate AMF set in descending order according to the priority of each AMF in the candidate AMF set, and the first message carries a terminal identifier and / or a NAS message. The first AMF that is determined to be reachable is determined as the target AMF that matches the terminal. Alternatively, the first AMF that responds to the NAS message is determined as the target AMF that matches the terminal.

[0374] In one embodiment, the selection module 1304 is used to send a broadcast message to each AMF in the candidate AMF set, the broadcast message carries the terminal identifier and the NAS message, and the AMF in the candidate AMF set that first responds to the broadcast message is determined as the target AMF matching the terminal.

[0375] In one embodiment, it also includes: a storage module, which is used to store the target AMF and the uplink route related to the target AMF in the terminal context after selecting the target AMF matching the terminal from the candidate AMF set and successfully establishing a link with the target AMF.

[0376] It should be noted here that the above-mentioned device provided in the embodiment of the present invention can implement all the method steps implemented in the above-mentioned method embodiment, and can achieve the same technical effect. The parts and beneficial effects that are the same as the method embodiment in this embodiment will not be described in detail here.

[0377] like Fig.14 As shown, the embodiment of the present application provides an AMF selection device 1400, which can be as follows Figure 1 The core network in the 5G system structure shown in the figure can meet the demand for on-demand connection of interfaces under the RAN service-oriented architecture and improve the flexibility of selecting signaling transmission paths. The device includes: a second receiving module 1401, a response module 1402, and a sending module 1403. The functional principles of each module are as follows:

[0378] The second receiving module 1401 is used to receive the NF discovery request sent by the wireless access network RAN, which carries a candidate AMF set matching the terminal and the terminal's demand information for AMF, wherein the candidate AMF set is determined by the RAN based on the terminal identifier and / or the terminal context locally stored in the RAN, and the demand information is determined by the RAN based on one or more of the terminal location information, the terminal access type, the slice information requested by the terminal, the terminal's capabilities and service requirements.

[0379] The response module 1402 is used to respond to the NF discovery request and determine the candidate AMF set available to the terminal based on the candidate AMF set, demand information, and the current status and load information of each AMF in the core network.

[0380] The sending module 1403 is used to send the candidate AMF set information to the RAN.

[0381] In one embodiment, the response module 1402 is used to respond to the NF discovery request, and determine the set of candidate AMFs available to the terminal through the target NRF in the core network that provides services to the terminal based on the candidate AMF set, demand information, and the current status and load information of each AMF in the core network, wherein the target NRF is determined by the RAN based on the mobile network identification code selected by the terminal.

[0382] In one embodiment, the response module 1402 is used to respond to the NF discovery request, and the target NRF providing services for the terminal sends a data analysis request to the network data analysis function NWDAF in the core network, and the data analysis request carries the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set, and the demand information, wherein the target NRF is determined by the RAN according to the mobile network identification code selected by the terminal. The second matching degree between each AMF in the candidate AMF set and the terminal is received from the NWDAF, wherein the second matching degree is determined by the NWDAF according to the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set, and the demand information. The target NRF determines the candidate AMF set based on the second matching degree.

[0383] In one embodiment, it also includes: a second auxiliary module, which is used for the target NRF to receive a registration request sent by the RAN, and the registration request carries the configuration information of the RAN and the AMF auxiliary indication. In response to the AMF auxiliary indication, the target NRF determines the optional AMF information set and the corresponding AMF matching rule set according to the configuration information of the RAN and the current status and load information of each AMF in the core network. The target NRF returns a response message to the RAN, wherein the response message carries the optional AMF information set and the corresponding AMF matching rule set.

[0384] In one embodiment, it also includes: a second update module, which is used for the target NRF to receive the AMF assisted update request sent by the RAN, and / or the subscription message of the RAN to the AMF assisted information update event. The target NRF determines the updated optional AMF information set and / or the updated AMF matching rule set based on the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network. In response to the AMF assisted update request, the target NRF returns the AMF update information to the RAN, and the AMF update information includes the updated optional AMF information set and / or the corresponding updated AMF matching rule set. And / or, in response to the subscription message, the target NRF notifies the AMF update information to the RAN, and the AMF update information includes the updated optional AMF information set and the corresponding updated AMF matching rule set.

[0385] It should be noted that the above-mentioned device provided in the embodiment of the present invention can implement all the method steps implemented in the above-mentioned method embodiment, and can achieve the same technical effect. The parts and beneficial effects that are the same as those in the method embodiment will not be described in detail here.

[0386] It should be noted that the division of modules in the embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present application may be integrated into a processing module, or each module may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0387] If the integrated module is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a processor-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) or a processor (processor) to perform all or part of the steps of each embodiment method of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), disk or optical disk and other media that can store program code.

[0388] An embodiment of the present application provides a processor-readable storage medium, which stores a computer program, and the computer program is used to enable the processor to execute the AMF selection method provided in any one of the above embodiments.

[0389] The processor-readable storage medium can be any available medium or data storage device that can be accessed by the processor, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO)), optical storage (such as CDs, DVDs, BDs, HVDs, etc.), and semiconductor storage (such as ROM, EPROM, EEPROM, non-volatile memory (NAND FLASH), solid-state drives (SSDs)), etc.

[0390] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0391] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer executable instructions. These computer executable instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0392] These processor executable instructions may also be stored in a processor readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the processor readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0393] These processor-executable instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0394] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. An AMF selection method, characterized in that: Applied to a radio access network RAN, the method comprises: Receiving a radio resource management RRC message sent by a terminal, wherein the RRC message carries a non-access stratum NAS message and attribute information of the terminal; Determining, according to the attribute information of the terminal, a target NF type of the core network specified by the NAS message; When the target NF type is an access and mobility management function AMF, determining a set of candidate AMFs available to the terminal according to the attribute information of the terminal; Select a target AMF that matches the terminal from the candidate AMF set.

2. The method according to claim 1, characterized in that: The attribute information of the terminal includes: one or more of an identifier of the terminal, an indication of a core network NF type, and a distribution mode of the NAS message; and determining, according to the attribute information of the terminal, a target NF type specified by the NAS message, includes: Determine the target NF type of the core network specified by the NAS message according to one or more of the terminal identifier, the core network NF type indication, and the NAS message distribution method.

3. The method according to claim 1, characterized in that The determining, according to the attribute information of the terminal, a candidate AMF set available to the terminal includes: Obtain AMF assistance information maintained locally in the radio access network RAN; Determine a set of candidate AMFs available to the terminal according to the attribute information of the terminal and / or the AMF auxiliary information.

4. The method according to claim 3, characterized in that The attribute information of the terminal includes: one or more of a terminal identification, a terminal location information, a terminal access type, a terminal capability, and a service requirement; the AMF auxiliary information includes an optional AMF information set; and determining, according to the attribute information of the terminal and / or the AMF auxiliary information, an alternative AMF set available to the terminal includes: Parse a first AMF matching the terminal according to the terminal identifier, and add the first AMF to the candidate AMF set; and / or, determining, according to the context information of the terminal stored locally in the RAN, a second AMF for which routing information already exists, and adding the second AMF to the candidate AMF set; and / or, adding a third AMF in the optional AMF information set that belongs to the same AMF group set as the first AMF or to the same AMF group set as the second AMF to the alternative AMF set; And / or, a fourth AMF in the optional AMF information set that matches one or more of the terminal location information, the terminal access type, the terminal capabilities and service requirements is added to the alternative AMF set.

5. The method according to claim 4, characterized in that The determining, according to the attribute information of the terminal and / or the AMF auxiliary information, a candidate AMF set available to the terminal further includes: Configure a priority for each AMF in the candidate AMF set, where the priority configuration rules include: Configuring the first AMF as the highest priority; and / or, configuring the second AMF as a second priority, the second priority being less than or equal to the first priority; And / or, configuring the third AMF as a third priority, wherein the third priority is lower than the second priority.

6. The method according to claim 4, characterized in that The AMF auxiliary information also includes an AMF matching rule set; and determining, according to the attribute information of the terminal and / or the AMF auxiliary information, a candidate AMF set available to the terminal, further includes: According to the AMF matching rule set, a fourth AMF in the optional AMF information set that matches one or more of the terminal location information, the terminal access type, the terminal capabilities and the service requirements is added to the candidate AMF set; and / or, evaluating, according to the terminal location information, the terminal access type, the capabilities and service requirements of the terminal, a first matching degree between each AMF in the fourth AMF and the terminal according to the AMF matching rule set; The fourth priority of each of the fourth AMFs is configured according to the first matching degree, wherein the first matching degree is positively correlated with the fourth priority of the corresponding fourth AMF.

7. The method according to claim 3, characterized in that Before the obtaining of the AMF auxiliary information locally maintained by the radio access network RAN, the step of generating the AMF auxiliary information is also included, including: Sending a registration request to the network repository function NRF of the core network, wherein the registration request carries the configuration information of the RAN and an indication requesting AMF assistance; Receive a response message returned by the NRF, the response message carrying an optional AMF information set and a corresponding AMF matching rule set, wherein the optional AMF information set and the AMF matching rule set are determined by the NRF according to the configuration information of the RAN and the current status and load information of each AMF in the core network; Generate the AMF auxiliary information according to the optional AMF information set and the AMF matching rule set.

8. The method according to claim 7, characterized in that The step of generating the AMF auxiliary information further includes: Send an AMF assistance update request to the NRF, and / or subscribe to AMF assistance information update events from the NRF; receiving the AMF update information returned by the NRF, the AMF update information including an updated optional AMF information set and / or a corresponding updated AMF matching rule set; wherein the updated optional AMF information set and / or the updated AMF matching rule set are determined by the NRF according to the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network; Update the AMF assistance information locally stored in the RAN according to the updated optional AMF information set and the updated AMF matching rule set.

9. The method according to claim 1, characterized in that: The attribute information of the terminal includes: one or more of: terminal identification, terminal location information, terminal access type, slice information requested by the terminal, terminal capabilities and service requirements, terminal context stored locally in the RAN, and a mobile network identification code selected by the terminal; determining, according to the attribute information of the terminal, a set of candidate AMFs available to the terminal, further includes: Determining a target NRF providing services to the terminal according to the mobile network identification code selected by the terminal; Determine, according to the terminal identifier and / or the terminal context, a set of candidate AMFs available to the terminal; Determine the terminal's demand information for the AMF according to one or more of the terminal location information, the terminal access type, the terminal's capabilities, and the service requirements; Sending an NF discovery request to the target NRF, the NF discovery request carrying the candidate AMF set and the requirement information, the NF discovery request being used to instruct the target NRF to return the candidate AMF set available to the terminal; Receive the set of alternative AMFs available to the terminal returned by the target NRF.

10. The method according to claim 9, characterized in that The candidate AMF set is determined by the target NRF based on the candidate AMF set, the demand information and the current status and load information of each AMF in the core network.

11. The method according to claim 9, characterized in that The candidate AMF set is determined by the target NRF based on the second matching degree between each AMF in the candidate AMF set and the terminal, and the second matching degree is determined by the network data analysis function NWDAF in the core network based on the configuration information of the radio access network RAN, the configuration information of each AMF in the candidate AMF set and the demand information.

12. The method according to claim 5, characterized in that The selecting a target AMF matching the terminal from the candidate AMF set further includes: According to the priority of each AMF in the candidate AMF set, send a first message to each AMF in the candidate AMF set in descending order, where the first message carries the terminal identifier and / or the NAS message; Determine the first reachable AMF as the target AMF matching the terminal; Alternatively, the first AMF that responds to the NAS message is determined as the target AMF that matches the terminal.

13. The method according to claim 1, characterized in that The selecting a target AMF matching the terminal from the candidate AMF set includes: Send a broadcast message to each AMF in the candidate AMF set, where the broadcast message carries the terminal identifier and the NAS message, and determine the AMF in the candidate AMF set that first responds to the broadcast message as the target AMF matching the terminal.

14. The method according to claim 1, characterized in that After selecting a target AMF matching the terminal from the candidate AMF set, the method further includes: After successfully establishing a link with the target AMF, the target AMF and the uplink route related to the target AMF are stored in the terminal context.

15. An AMF selection method, characterized in that: Applied to a core network, the method comprises: Receiving an NF discovery request sent by a radio access network RAN, the NF discovery request carrying a candidate AMF set matching the terminal and demand information of the terminal for the AMF, wherein the candidate AMF set is determined by the RAN according to the terminal identifier and / or the terminal context locally stored in the RAN, and the demand information is determined by the RAN according to one or more of the terminal location information, the terminal access type, the slice information requested by the terminal, and the capabilities and service requirements of the terminal; In response to the NF discovery request, determine the candidate AMF set available to the terminal according to the candidate AMF set, the demand information and the current status and load information of each AMF in the core network; Send the candidate AMF set information to the RAN.

16. The method according to claim 15, characterized in that The step of responding to the NF discovery request, determining the candidate AMF set available to the terminal according to the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, includes: In response to the NF discovery request, the target NRF in the core network that provides services to the terminal determines the set of candidate AMFs available to the terminal based on the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, wherein the target NRF is determined by the RAN based on the mobile network identification code selected by the terminal.

17. The method according to claim 15, characterized in that The step of responding to the NF discovery request, determining the candidate AMF set available to the terminal according to the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, includes: In response to the NF discovery request, the target NRF providing services for the terminal sends a data analysis request to a network data analysis function NWDAF in the core network, where the data analysis request carries the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set, and the demand information, wherein the target NRF is determined by the RAN according to the mobile network identification code selected by the terminal; Receiving a second matching degree between each AMF in the candidate AMF set and the terminal returned by the NWDAF, wherein the second matching degree is determined by the NWDAF according to the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set and the requirement information; The target NRF determines the candidate AMF set according to the second matching degree.

18. The method according to claim 15, characterized in that Also includes: The target NRF receives a registration request sent by the RAN, where the registration request carries configuration information of the RAN and an AMF assistance indication; In response to the AMF assistance indication, the target NRF determines an optional AMF information set and a corresponding AMF matching rule set according to the configuration information of the RAN and the current status and load information of each AMF in the core network; The target NRF returns a response message to the RAN, wherein the response message carries an optional AMF information set and a corresponding AMF matching rule set.

19. The method according to claim 18, characterized in that Also includes: The target NRF receives an AMF assisted update request sent by the RAN, and / or a subscription message of the RAN to an AMF assistance information update event; The target NRF determines an updated optional AMF information set and / or an updated AMF matching rule set according to the configuration information of the RAN, the optional AMF set, and the updated status and load information of each AMF in the core network; In response to the AMF assisted update request, the target NRF returns AMF update information to the RAN, the AMF update information including an updated optional AMF information set and / or a corresponding updated AMF matching rule set; And / or, in response to the subscription message, the target NRF notifies the RAN of AMF update information, wherein the AMF update information includes an updated optional AMF information set and a corresponding updated AMF matching rule set.

20. An AMF selection device, characterized in that: Applied to a radio access network RAN, the device comprises: a memory, a transceiver, and a processor: A memory for storing a computer program; a transceiver for transmitting and receiving data under the control of the processor; and a processor for reading the computer program in the memory and performing the following operations: Receiving a radio resource management RRC message sent by a terminal, wherein the RRC message carries a non-access stratum NAS message and attribute information of the terminal; Determining, according to the attribute information of the terminal, a target NF type of the core network specified by the NAS message; When the target NF type is an access and mobility management function AMF, determining a set of candidate AMFs available to the terminal according to the attribute information of the terminal; Select a target AMF that matches the terminal from the candidate AMF set.

21. The device according to claim 20, characterized in that The attribute information of the terminal includes: one or more of an identifier of the terminal, an indication of a core network NF type, and a distribution mode of the NAS message; and determining, according to the attribute information of the terminal, a target NF type specified by the NAS message, includes: Determine the target NF type of the core network specified by the NAS message according to one or more of the terminal identifier, the core network NF type indication, and the NAS message distribution method.

22. The device according to claim 20, characterized in that The determining, according to the attribute information of the terminal, a candidate AMF set available to the terminal includes: Obtain AMF assistance information maintained locally in the radio access network RAN; Determine a set of candidate AMFs available to the terminal according to the attribute information of the terminal and / or the AMF auxiliary information.

23. The device according to claim 22, characterized in that The attribute information of the terminal includes: one or more of a terminal identification, a terminal location information, a terminal access type, a terminal capability, and a service requirement; the AMF auxiliary information includes an optional AMF information set; and determining, according to the attribute information of the terminal and / or the AMF auxiliary information, an alternative AMF set available to the terminal includes: Parse a first AMF matching the terminal according to the terminal identifier, and add the first AMF to the candidate AMF set; and / or, determining, according to the context information of the terminal stored locally in the RAN, a second AMF for which routing information already exists, and adding the second AMF to the candidate AMF set; and / or, adding a third AMF in the optional AMF information set that belongs to the same AMF group set as the first AMF or to the same AMF group set as the second AMF to the alternative AMF set; And / or, a fourth AMF in the optional AMF information set that matches one or more of the terminal location information, the terminal access type, the terminal capabilities and service requirements is added to the alternative AMF set.

24. The device according to claim 23, characterized in that The determining, according to the attribute information of the terminal and / or the AMF auxiliary information, a candidate AMF set available to the terminal further includes: Configure a priority for each AMF in the candidate AMF set, where the priority configuration rules include: Configuring the first AMF as the highest priority; and / or, configuring the second AMF as a second priority, the second priority being less than or equal to the first priority; And / or, configuring the third AMF as a third priority, wherein the third priority is lower than the second priority.

25. The device according to claim 23, characterized in that The AMF auxiliary information also includes an AMF matching rule set; and determining, according to the attribute information of the terminal and / or the AMF auxiliary information, a candidate AMF set available to the terminal, further includes: According to the AMF matching rule set, a fourth AMF in the available selected AMF information set that matches one or more of the terminal location information, the terminal access type, the terminal capabilities and service requirements is added to the candidate AMF set; and / or, evaluating, according to the terminal location information, the terminal access type, the capabilities and service requirements of the terminal, a first matching degree between each AMF in the fourth AMF and the terminal according to the AMF matching rule set; The fourth priority of each of the fourth AMFs is configured according to the first matching degree, wherein the first matching degree is positively correlated with the fourth priority of the corresponding fourth AMF.

26. The device according to claim 22, characterized in that Before the obtaining of the AMF auxiliary information locally maintained by the radio access network RAN, the step of generating the AMF auxiliary information is also included, including: Sending a registration request to a network repository function NRF of the core network, wherein the registration request carries the configuration information of the RAN and an AMF assistance indication; Receive a response message returned by the NRF, the response message carrying an optional AMF information set and a corresponding AMF matching rule set, wherein the optional AMF information set and the AMF matching rule set are determined by the NRF according to the configuration information of the RAN and the current status and load information of each AMF in the core network; Generate the AMF auxiliary information according to the optional AMF information set and the AMF matching rule set.

27. The device according to claim 26, characterized in that The step of generating the AMF auxiliary information further includes: Send an AMF assistance update request to the NRF, and / or subscribe to AMF assistance information update events from the NRF; receiving the AMF update information returned by the NRF, the AMF update information including an updated optional AMF information set and / or a corresponding updated AMF matching rule set; wherein the updated optional AMF information set and / or the updated AMF matching rule set are determined by the NRF according to the configuration information of the RAN, the optional AMF set and the updated status and load information of each AMF in the core network; Update the AMF assistance information locally stored in the RAN according to the updated optional AMF information set and the updated AMF matching rule set.

28. The device according to claim 20, characterized in that The attribute information of the terminal includes: one or more of: terminal identification, terminal location information, terminal access type, slice information requested by the terminal, terminal capabilities and service requirements, terminal context stored locally in the RAN, and a mobile network identification code selected by the terminal; determining, according to the attribute information of the terminal, a set of candidate AMFs available to the terminal, further includes: Determining a target NRF providing services to the terminal according to the mobile network identification code selected by the terminal; Determine, according to the terminal identifier and / or the terminal context, a set of candidate AMFs available to the terminal; Determine the terminal's demand information for the AMF according to one or more of the terminal location information, the terminal access type, the terminal's capabilities, and the service requirements; Sending an NF discovery request to the target NRF, the NF discovery request carrying the candidate AMF set and the requirement information, the NF discovery request being used to instruct the target NRF to return the candidate AMF set available to the terminal; Receive the set of alternative AMFs available to the terminal returned by the target NRF.

29. The device according to claim 28, characterized in that The candidate AMF set is determined by the target NRF based on the candidate AMF set, the demand information and the current status and load information of each AMF in the core network.

30. The device according to claim 28, characterized in that The candidate AMF set is determined by the target NRF based on the second matching degree between each AMF in the candidate AMF set and the terminal, and the second matching degree is determined by the network data analysis function NWDAF in the core network based on the configuration information of the radio access network RAN, the configuration information of each AMF in the candidate AMF set and the demand information.

31. The device according to claim 24, characterized in that The selecting a target AMF matching the terminal from the candidate AMF set further includes: According to the priority of each AMF in the candidate AMF set, send a first message to each AMF in the candidate AMF set in descending order, where the first message carries the terminal identifier and / or the NAS message; Determine the first reachable AMF as the target AMF matching the terminal; Alternatively, the first AMF that responds to the NAS message is determined as the target AMF that matches the terminal.

32. The device according to claim 20, characterized in that The selecting a target AMF matching the terminal from the candidate AMF set includes: Send a broadcast message to each AMF in the candidate AMF set, where the broadcast message carries the terminal identifier and the NAS message, and determine the AMF in the candidate AMF set that first responds to the broadcast message as the target AMF matching the terminal.

33. An AMF selection device, characterized in that: Applied to a core network, the device includes: a memory, a transceiver, and a processor: A memory for storing a computer program; a transceiver for transmitting and receiving data under the control of the processor; and a processor for reading the computer program in the memory and performing the following operations: Receiving an NF discovery request sent by a radio access network RAN, the NF discovery request carrying a candidate AMF set matching the terminal and demand information of the terminal for the AMF, wherein the candidate AMF set is determined by the RAN according to the terminal identifier and / or the terminal context locally stored in the RAN, and the demand information is determined by the RAN according to one or more of the terminal location information, the terminal access type, the slice information requested by the terminal, and the capabilities and service requirements of the terminal; In response to the NF discovery request, determine the candidate AMF set available to the terminal according to the candidate AMF set, the demand information and the current status and load information of each AMF in the core network; Send the candidate AMF set information to the RAN.

34. The device according to claim 33, characterized in that The step of responding to the NF discovery request, determining the candidate AMF set available to the terminal according to the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, includes: In response to the NF discovery request, the target NRF in the core network that provides services to the terminal determines the set of candidate AMFs available to the terminal based on the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, wherein the target NRF is determined by the RAN based on the mobile network identification code selected by the terminal.

35. The device according to claim 33, characterized in that The step of responding to the NF discovery request, determining the candidate AMF set available to the terminal according to the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network, includes: In response to the NF discovery request, the target NRF providing services for the terminal sends a data analysis request to a network data analysis function NWDAF in the core network, where the data analysis request carries the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set, and the demand information, wherein the target NRF is determined by the RAN according to the mobile network identification code selected by the terminal; Receiving a second matching degree between each AMF in the candidate AMF set and the terminal returned by the NWDAF, wherein the second matching degree is determined by the NWDAF according to the configuration information of the RAN, the configuration information of each AMF in the candidate AMF set and the requirement information; The target NRF determines the candidate AMF set according to the second matching degree.

36. The device according to claim 33, characterized in that Also includes: The target NRF receives a registration request sent by the RAN, where the registration request carries configuration information of the RAN and an AMF assistance indication; In response to the AMF assistance indication, the target NRF determines an optional AMF information set and a corresponding AMF matching rule set according to the configuration information of the RAN and the current status and load information of each AMF in the core network; The target NRF returns a response message to the RAN, wherein the response message carries an optional AMF information set and a corresponding AMF matching rule set.

37. The device according to claim 36, characterized in that Also includes: The target NRF receives an AMF assisted update request sent by the RAN, and / or a subscription message of the RAN to an AMF assistance information update event; The target NRF determines an updated optional AMF information set and an updated AMF matching rule set according to the configuration information of the RAN, the optional AMF set, and the updated status and load information of each AMF in the core network; In response to the AMF assisted update request, the target NRF returns AMF update information to the RAN, the AMF update information including an updated optional AMF information set and a corresponding updated AMF matching rule set; And / or, in response to the subscription message, the target NRF notifies the RAN of AMF update information, wherein the AMF update information includes an updated optional AMF information set and a corresponding updated AMF matching rule set.

38. An AMF selection device, characterized in that: Applied to a radio access network RAN, the device comprises: A first receiving module, configured to receive a radio resource management RRC message sent by a terminal, wherein the RRC message carries a non-access stratum NAS message and attribute information of the terminal; A first determination module, configured to determine a target NF type of the core network specified by the NAS message according to the attribute information of the terminal; A second determination module is used to determine, when the target NF type is an access and mobility management function AMF, a candidate AMF set available to the terminal according to the attribute information of the terminal; A selection module is used to select a target AMF that matches the terminal from the candidate AMF set.

39. An AMF selection device, characterized in that: Applied to a core network, the device comprises: A second receiving module is configured to receive an NF discovery request sent by a radio access network RAN, wherein the NF discovery request carries a candidate AMF set matching the terminal and demand information of the terminal for the AMF, wherein the candidate AMF set is determined by the RAN according to the terminal identifier and / or the terminal context locally stored in the RAN, and the demand information is determined by the RAN according to one or more of the terminal location information, the terminal access type, the slice information requested by the terminal, and the capabilities and service requirements of the terminal; A response module, configured to respond to the NF discovery request and determine a candidate AMF set available to the terminal according to the candidate AMF set, the demand information, and the current status and load information of each AMF in the core network; A sending module is used to send the candidate AMF set information to the RAN.

40. A processor-readable storage medium, characterized in that: The processor-readable storage medium stores a computer program, and the computer program is used to cause the processor to execute the method of any one of claims 1-14 or claims 15-19.

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