KR20210054970A - Method and apparatus for controlling network slice in a wireless communication system - Google Patents

Abstract

A method for allowing an access and mobility management function (AMF) to control a network slice in a wireless communication system comprises the following steps of: transmitting a selection request of a network slice; receiving a candidate of the network slice for the selection request; determining a quota of the received network slice candidate; and controlling whether a user terminal accesses the network slice candidate based on the determined quota. Therefore, the present invention can effectively provide a service in a wireless communication system.

Description

A method and apparatus for controlling a network slice in a wireless communication system {METHOD AND APPARATUS FOR CONTROLLING NETWORK SLICE IN A WIRELESS COMMUNICATION SYSTEM}

The present disclosure relates to a method and apparatus for controlling a network slice in a wireless communication system.

Efforts are being made to develop an improved 5G (5th generation) communication system or a pre-5G communication system in order to meet the increasing demand for wireless data traffic after the commercialization of 4G (4th generation) communication systems. For this reason, the 5G communication system or the pre-5G communication system is called a Beyond 4G Network communication system or a Long Term Evolution (LTE) system (Post LTE) system.

In order to achieve a high data rate, 5G communication systems are being considered for implementation in an ultra-high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the propagation distance of radio waves, in 5G communication systems, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed.

In addition, in order to improve the network of the system, in 5G communication systems, an evolved small cell, an advanced small cell, a cloud radio access network (cloud RAN), and an ultra-dense network ), Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation ) And other technologies are being developed.

In addition, in the 5G system, the advanced coding modulation (Advanced Coding Modulation, ACM) method of FQAM (Hybrid Frequency Shift Keying and Quadrature Amplitude Modulation) and SWSC (Sliding Window Superposition Coding), and advanced access technology, FBMC (Filter Bank Multi Carrier). ), NOMA (Non Orthogonal Multiple Access), and SCMA (Sparse Code Multiple Access) are being developed.

With the development of various information technology (IT) technologies, virtualization technology has been applied to network equipment, and communication equipment has evolved into a virtualized network function (NF). In addition, virtualized NFs can be installed/operated in various types of clouds or data centers (DCs) because they are implemented in software form without physical restrictions. In particular, the NF can be freely expanded or scaled, installed (initiation), or terminated according to service requirements, system capacity, and network load. It should be noted that even though these NFs are implemented in software form, they are not excluded from the physical configuration, since they must be driven on a basic physical configuration, for example, a predetermined device. In addition, NFs may be implemented only with a simple physical configuration, that is, hardware.

In order to support various services in these various network structures, network slicing technology has been introduced. Network slicing is a technology that logically composes a network as a set of network functions (NF) to support a specific service and separates it from other slices. One terminal can access two or more slices when receiving various services.

An embodiment of the present disclosure may provide a method and an apparatus for more effectively providing a service.

According to an embodiment of the present disclosure, a method of controlling a network slice by an Access and Mobility Management Function (AMF) includes: transmitting a request for selecting the network slice; Receiving a candidate of the network slice for the selection request; Determining a quota of the received network slice candidate; And controlling whether a user terminal accesses the network slice candidate based on the determined quota.

According to an embodiment of the present disclosure, a service can be more effectively provided.

1 is a diagram illustrating a wireless communication system according to an embodiment of the present disclosure.
2 is a diagram illustrating a configuration of a wireless communication system according to an embodiment of the present disclosure.
3 is a flowchart illustrating a procedure for performing access control for each network slice according to an embodiment of the present disclosure.
4 is another flowchart illustrating a procedure for performing access control for each network slice according to an embodiment of the present disclosure.
5 is a flowchart illustrating a procedure for providing a service by transitioning a terminal to another wireless connection according to an embodiment of the present disclosure.
6 is a diagram illustrating a configuration of a terminal according to an embodiment of the present disclosure.
7 is a diagram illustrating a configuration of a network entity according to an embodiment of the present disclosure.
8 is another diagram illustrating a configuration of a network entity according to an embodiment of the present disclosure.
9 is a diagram illustrating an operation of a terminal and a network according to an embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to more clearly convey the gist of the present disclosure by omitting unnecessary description.

For the same reason, some elements in the accompanying drawings are exaggerated, omitted, or schematically illustrated. In addition, the size of each component does not fully reflect the actual size. The same reference numerals are assigned to the same or corresponding components in each drawing.

Advantages and features of the present disclosure, and a method of achieving them will be apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the present disclosure complete, and those skilled in the art to which the present disclosure pertains. It is provided to fully inform the scope of the disclosure to the person, and the present disclosure is only defined by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

At this time, it will be appreciated that each block of the flowchart diagrams and combinations of the flowchart diagrams may be executed by computer program instructions. Since these computer program instructions can be mounted on the processor of a general purpose computer, special purpose computer or other programmable data processing equipment, the instructions executed by the processor of the computer or other programmable data processing equipment are described in the flowchart block(s). It creates a means to perform functions. These computer program instructions can also be stored in computer-usable or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement a function in a particular way, so that the computer-usable or computer-readable memory It is also possible for the instructions stored in the flow chart to produce an article of manufacture containing instruction means for performing the functions described in the flowchart block(s). Since computer program instructions can also be mounted on a computer or other programmable data processing equipment, a series of operating steps are performed on a computer or other programmable data processing equipment to create a computer-executable process to create a computer or other programmable data processing equipment. It is also possible for instructions to perform processing equipment to provide steps for executing the functions described in the flowchart block(s).

In addition, each block may represent a module, segment, or part of code that contains one or more executable instructions for executing the specified logical function(s). In addition, it should be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order depending on the corresponding function.

In this case, the term'~ unit' used in this embodiment refers to software or hardware components such as FPGA or ASIC, and'~ unit' performs certain roles. However,'~ part' is not limited to software or hardware. The'~ unit' may be configured to be in an addressable storage medium, or may be configured to reproduce one or more processors. Thus, as an example,'~ unit' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, database, data structures, tables, arrays, and variables. Components and functions provided in the'~ units' may be combined into a smaller number of elements and'~ units', or may be further separated into additional elements and'~ units'. In addition, components and'~ units' may be implemented to play one or more CPUs in a device or a security multimedia card. In addition, in an embodiment, the'~ unit' may include one or more processors.

A term for identifying an access node used in the following description, a term for network entities, a term for messages, a term for an interface between network objects, a term for various identification information And the like are illustrated for convenience of description. Accordingly, the present disclosure is not limited to terms to be described later, and other terms referring to objects having an equivalent technical meaning may be used.

For convenience of description below, the present disclosure uses terms and names defined in standards for 5G, New Radio (NR), and Long Term Evolution (LTE) systems. However, the present disclosure is not limited by terms and names, and may be equally applied to systems conforming to other standards.

In describing the embodiments of the present disclosure in detail, the communication standard defined by the 3GPP will be the main target, but the main subject of the present disclosure does not significantly depart from the scope of the present disclosure to other communication systems having a similar technical background. It may be applied with slight modifications in the range of, and this will be possible at the judgment of a person skilled in the technical field of the present disclosure.

In describing the embodiments of the present disclosure in detail, the vehicle communication service will be the main target, but the main gist of the present disclosure is, within the range not significantly departing from the scope of the present disclosure, even to other services provided in the 5G network. It can be applied as a modification, and this will be possible at the judgment of a person skilled in the technical field of the present disclosure. In other words, the ProSe layer dealt with in the present disclosure may mean the overall layer performing a control operation for a device to device (or D2D, or ProSe: Proximity Service) communication service. This exists on the AS layer and refers to a layer that exchanges signaling with the AS layer for terminal-to-terminal communication connection.

The 5G system is considering supporting various services compared to the existing 4G system. For example, the most representative services are mobile ultra-wideband communication service (eMBB: enhanced mobile broad band), ultra-reliable and low latency communication service (URLLC: ultra-reliable and low latency communication), and large-scale device-to-device communication service (mMTC: massive machine type communication), evolved multimedia broadcast/multicast service (eMBMS), and the like. In addition, a system providing a URLLC service may be referred to as a URLLC system, and a system providing an eMBB service may be referred to as an eMBB system. Also, the terms service and system may be used interchangeably.

Hereinafter, the present disclosure relates to a method and apparatus for supporting various services in a wireless communication system. Specifically, the present disclosure describes a technology for supporting various services by supporting mobility of a terminal in a wireless communication system.

A term for identifying an access node used in the following description, a term for a network entity or a network function (NF), a term for messages, and an interface between network objects. Terms, terms referring to various types of identification information, and the like are exemplified for convenience of description. Accordingly, the present disclosure is not limited to terms to be described later, and other terms referring to objects having an equivalent technical meaning may be used.

For convenience of description below, this disclosure uses terms and names defined in 3GPP 3rd generation partnership project long term evolution (LTE) and 5G standards. However, the present disclosure is not limited by the terms and names, and may be equally applied to systems conforming to other standards.

Hereinafter, for convenience of description, targets for exchanging information for access control and state management will be collectively described as NF. NF is, for example, an access and mobility management function (Access and Mobility Management Function, hereinafter referred to as AMF) device, a session management function (Session Management Function, hereinafter referred to as SMF) device, a network slice selection function device (Network slice selection function). , NSSF) may be at least one of the devices. However, the embodiments of the present disclosure may be equally applied even when NF is actually implemented as an instance (Instance, respectively AMF Instance, SMF Instance, NSSF Instance, etc.).

In an embodiment of the present invention, the meaning of delivering information or policy on a radio access technology (RAT) has the same meaning as delivering information or policy about an access type that can be used when selecting a specific RAT.

1 is a diagram illustrating a wireless communication system according to an embodiment of the present disclosure.

Referring to FIG. 1, a radio access node (RAN) 110 and a user equipment (UE) 120 are illustrated as some of nodes using a radio channel in a wireless communication system. 1 shows only one base station 110 and one terminal 120, but another base station identical or similar to the base station 110 may be further included. In addition, in FIG. 1, only a case in which only one terminal 120 communicates within one base station 110 is illustrated. However, it is obvious that a plurality of terminals can communicate within one base station 110.

The base station 110 is a network infrastructure that provides wireless access to the terminal 120. The base station 110 has a coverage defined as a certain geographic area based on a distance at which a signal can be transmitted (not shown in FIG. 1). In addition to the base station, the base station 110 includes'access point (AP)','eNodeB, eNB', '5G node', and'wireless point'. , May be referred to as'transmission/reception point (TRP)' or another term having an equivalent technical meaning.

The terminal 120 is a device used by a user and performs communication with the base station 110 through a radio channel. In some cases, the terminal 120 may be operated without the user's involvement. For example, the terminal 120 is a device that performs machine type communication (MTC) and may not be carried by a user. The terminal 120 illustrated in FIG. 1 may include at least one user portable device, and may include at least one MTC. The terminal 120 of FIG. 1 is a'terminal', a'mobile station', a'subscriber station', a'remote terminal', a'wireless terminal', Alternatively, it may be referred to as'user device' or another term having a technical meaning equivalent thereto.

The AMF device 131 may be a network entity that manages the mobility of the terminal 120. The SMF device 132 may be a network entity that manages connection of a packet data network for providing packet data to the terminal 120. The connection between the terminal 120 and the SMF 132 may be a PDU session.

The user plane function (hereinafter referred to as UPF) device 133 may be a gateway through which packets transmitted and received by the terminal 120 are transmitted or a network entity that functions as a gateway. The UPF 133 may be connected to a data network (DN) 140 connected to the Internet, and may provide a path for transmitting and receiving data between the terminal 120 and the DN 140. Accordingly, the UPF 133 may route data to be transmitted to the Internet among packets transmitted by the terminal 120 to the Internet data network.

The network slice selection function (NSSF) device 134 may be a network entity that performs a network selection operation described in the present disclosure, for example, an operation of selecting a network slice. The operation of the NSSF device 134 will be described in more detail in the drawings to be described later.

The authentication server function (AUSF) device 151 may be a network entity that provides a subscriber authentication service.

The network exposure function (NEF) device 152 can access information managing the terminal 120 in a 5G network, subscribe to the mobility management event of the terminal, and a session of the terminal Network entity that can subscribe to session management events, request session-related information, set billing information for the terminal, request to change the PDU session policy for the terminal, and transmit small data about the terminal Can be.

NRF (Network Repository Function, 153) is a profile containing detailed information of each NF (Network Function), or an NF or network entity that stores status information of NF or NF Instance. The profile or status information of the stored NF can be delivered.

The policy and charging function (Policy and Charging Function, hereinafter referred to as PCF) device 154 may be a network entity that applies a service policy of a mobile communication service provider to the terminal 120, a charging policy, and a policy for a PDU session. have.

The integrated data management (Unified Data Management, hereinafter referred to as UDM) device 155 may be a network entity that stores information about the subscriber or/and the terminal 120.

The AF (Application Function) 156 may be a service application server or a network entity that provides a service by interworking with a network.

AMF device 131, SMF device 132, UPF device 133, NSSF device 134, AUSF device 151, NEF device 152, NRF device 153, PCF device 154 described above , The UDM device 155, the AF device 156, and the SCP device 157 may be software driven by at least one or more devices or/and systems, or may be in the form of firmware. In addition, the above-described devices 131, 132, 133, 134, 151, 152, 153, 154, 155, 156, and 157 may be implemented in the form of hardware, if necessary. In the following description, for convenience of description, the term "device" will be omitted. For example, the AMF device 131 will be described as AMF 131 and the SMF device 132 will be described in the same form as the SMF 132.

Meanwhile, in FIG. 1, symbols between lines connected between each network entity, the terminal 120 and the RAN 110 may be interfaces of each entity. For example, an N1 interface is used between the terminal 120 and the AMF 131, an N2 interface is used between the RAN 110 and the AMF 131, and an N3 interface is used between the RAN 110 and the UPF 133. It can mean that it is used. Similarly, the N4 interface is used between the SMF 132 and the UPF 133, the N9 interface is used between or inside the UPF 133, and the N6 interface may be used between the UPF 133 and the DN 140. .

2 is a diagram illustrating a configuration of a wireless communication system according to various embodiments of the present disclosure.

Referring to FIG. 2, a mobile communication system (a carrier network such as 5G or 4G) may be composed of a radio base station, for example, a radio access network (RAN) 110 and one or more core network slices. In FIG. 2, N core network slices 211, 212, ..., 21N are illustrated. The RAN 110 may transmit/receive data between a terminal (eg, the terminal 120 of FIG. 1 and the data network (DN) 140) through at least one core network slice. Accordingly, the core network can be configured in a slice form or without a slice, and coexistence between the two is also possible One core network slice may basically include NFs of one or more core networks One core network The NF corresponding to may include the AMF 131, the SMF 132, and the UPF 133. In addition, according to another embodiment, the NF is among the AMF 131, the SMF 132, and the UPF 133. According to another embodiment, the NF may further include other network function devices in addition to the AMF 131, the SMF 132, and the UPF 133. Another embodiment According to the NF, the AMF 131, the SMF 132, and the UPF 133 may include at least one or more components, and may further include at least one other device in addition to the above-described devices.

In an embodiment of the present disclosure, each of the network slices 211, 212, ..., 21N may provide a service suitable for each characteristic, and each of the network slices 211, 212, ..., Each 21N) may have different capacities that can be provided at the same time. The capacity of the network slices 211, 212, ..., 21N may be, for example, the maximum number of terminals (subscribers) and the number of sessions. Each of the network slices 211, 212, ..., 21N may control access to the network according to its own capacity.

Referring to FIG. 2, a case in which 10,000 terminals can be connected to the first network slice 211 and 30,000 sessions can be accommodated is illustrated. A case in which 50,000 terminals can be connected to the second network slice 212 and 100,000 sessions can be accommodated is illustrated. In addition, the case where 1,000 terminals can be accessed and 5,000 sessions can be accommodated is exemplified in the N-th network slice 21N.

As shown in FIG. 2, the capacity of each of the network slices 211, 212, ..., 21N may be set differently for each slice according to the setting of the mobile communication service provider. If one specific slice is leased or sold to a separate service provider, the capacity may be set differently for each slice according to a service level agreement (SLA).

According to an embodiment of the present disclosure, the capacity (Quota or Capacity) of one network slice may be expressed as at least one of the following parameters.

One. Maximum number of subscribers, terminals, or users that can simultaneously access a network slice

2. The maximum number of PDU sessions that can be supported simultaneously in a network slice.

3. Maximum number of IP flows that can be simultaneously supported in network slice

4. Maximum number of QoS flows that can be simultaneously supported in network slice

5. Maximum number of GBR flows that can be supported simultaneously in network slice

According to an embodiment of the present disclosure, the capacity of one network slice is set as the number of terminals that can be simultaneously connected (parameter 1) and the maximum number of sessions that can be simultaneously supported (parameter 2), as shown in FIG. Can be. In addition, the capacity of one network slice may be set using at least one or two or more of the above-described parameters.

On the other hand, parameters related to session and flow (e.g., in the case of 2 to 5 of the above-described parameters) are expressed as predetermined values per slice (e.g., 10,000 sessions per network slice are supported), or It may be expressed as a specific value per one terminal (for example, up to four sessions are supported at the same time per terminal connected to a network slice).

According to an embodiment of the present disclosure, through capacity control for each network slice, a mobile communication network of a service provider is protected from overload, resources of the network are effectively used, and accurate billing between the mobile communication service provider and the network slice user can be performed. have.

Meanwhile, according to an embodiment of the present disclosure, when access control using a quota is performed for each network slice, a case may occur when a limit value of a quota set in an actual slice is reached. If the quota of a slice is set to the maximum number of concurrent users (or terminals), a technique for handling the request when a connection request exceeding the quota occurs is required.

According to an embodiment of the present disclosure, a method of processing an access request generated when a maximum concurrent accessor reaches a limit of a quota may be proposed as follows.

One) Connection Reject: The terminal that sent the connection request can know through the Reject message that the connection request has been rejected.At this time, the terminal can control the cause of the rejection due to the quota of the slice (i.e., the maximum value set in the quota). Reached). In addition, the terminal may receive a timer value for allowing the reconnection request. If the connection request was a registration request for the slice(s), and a Reject occurs during the control process for the maximum number of users, the timer is applied to the slice(s), and the terminal does not stop until the timer expires. Do not retransmit a connection request for the slice(s). If the connection request was for a session (Data Network Name, DNN) mapped to a specific slice, and a Reject occurs during the control process for the maximum number of sessions, the timer is set to the corresponding slice(s) and the mapped DNN(s). As applied to, the terminal should not retransmit a session creation request for the corresponding slice(s) and the mapped DNN(s) until the timer expires. If the timer expires, the terminal may retransmit an access or session creation request.

2) Fallback to another slice or Radio Access Technology (RAT): A different slice may be selected instead of the slice for which the connection has been requested (Fallback), and an access (or session creation) process may be performed to the UE. At this time, whether fallback is allowed or default slice information or RAT information to be the target of fallback is included in subscription information through UDM, access control policy through PCF, or a value set in AMF/SMF Can be used. If a fallback occurs to another slice, the terminal that sent the connection request can know through a message that the connection (or session creation) request has been accepted. In this case, the message includes information indicating that the user has been refused to use the slice for which the access request is made because the maximum allowed capacity has been exceeded, but has fallen back to another slice. If a fallback occurs to another RAT, the currently received registration request is rejected and information to move to another RAT is given, or the currently received registration request is accepted and the capacity is exceeded for slices requested by the terminal. May be rejected due to, and may contain information to transition to another RAT. In addition, the terminal may receive a timer value for allowing the reconnection request. If the connection request was a registration request for the slice(s), and a fallback occurs during the control process for the maximum number of users, the timer is applied to the slice(s), and the terminal is required until the timer expires. The change request must not be retransmitted for the slice(s). If the connection request was for a session (DNN) mapped to a specific slice, and a fallback occurs to another DNN during the control process for the maximum number of sessions, the timer is set to the corresponding slice(s) and the mapped DNN(s). As applicable, the UE must not retransmit a session creation change request for the corresponding slice(s) and the mapped DNN(s) until the timer expires. If the timer expires, the terminal may change the slice by retransmitting an access or session creation request. In another embodiment, when 5GC (5G Core) knows that access to a slice to which Fallback has been applied is possible, a message indicating that access is possible by changing to the originally requested slice(s) or DNN can be transmitted to the terminal. have. At this time, the message notifying the change may include information indicating that an NF change such as AMF or SMF due to the changed slice, and a NAS procedure for this, should be performed. If the NF change is not necessary, the terminal receiving it assumes that the slice has changed and operates, and if the NF change is required, it can perform an operation (registration when changing AMF, PDU session establishment when changing SMF). have.

3 is a flowchart illustrating a procedure for performing access control for each network slice according to an embodiment of the present disclosure.

Referring to FIG. 3, the NSSF 134 may provide information on a network slice. However, instead of the NSSF 134, the NRF 153, the SCP 157, or the PCF 154 may perform this.

In step S310, the terminal 120 may transmit a connection request (RRC Connection (Network Slice Selection Assistance Information, NSSAI)) message to the NG-RAN 110 by selecting a network slice to which it is to be accessed. What is illustrated as the NG-RAN 110 in FIG. 3 is an example of a base station and is not limited thereto. That is, any of the above-described various types of base stations may be used.

In step S311, the base station (NG-RAN, 110) may select the AMF 131 using the network slice identifier specified by the terminal 120, and the connection request message transmitted by the terminal 120, for example, N1 (NAS) An initial UE message (Initial UE message-Registration Req (Requested NSSAI)) including a registration request may be delivered to the AMF 131 based on a message (a registration request message described above).

The AMF 131 may perform an operation for processing a registration request message transmitted from the terminal 120 through the base station. If the AMF 131 needs to receive subscription data for the terminal 120, it may receive subscription information from the UDM 155, and at this time, the access and mobility-related subscription information includes the terminal 120 Slice information (one or more Subscribed S-NSSAI) subscribed to may be included (step S312).

In step S313, if a new network slice should be selected for the terminal 120, or a network slice should be changed, or when a new AMF 131 belonging to the network slice should be selected, the AMF 131 is NSSF A network slice selection request (NSSelection Req) message may be transmitted to (134). The network slice selection request (NSSelection Req) message may be performed through a GET operation of the Nnssf_NSSelection Service provided by the NSSF 134. At this time, the information for slice selection may be requested from the NRF 153, the SCP 157, or the PCF 154 instead of the NSSF 134. In this case, Service Operation for each NF may be used, or information stored in the AMF 131 may be used. When transmitting a network slice selection request (NSSelection Req) message, the AMF may include network slice identifiers (Requested NSSAI) requested by the terminal 120, and network slice identifiers (subscribed NSSAI) included in subscription information. In addition, when transmitting a network slice selection request (NSSelection Req) message, the AMF 131 may notify that the selection target is all NFs included in the network slice, or may designate a specific NF Type in the network slice to be selected.

In step S314, the NSSF 134 may perform an operation for selecting a network slice according to the request of the AMF 131. At this time, information per slice (maximum capacity per slice, current load (usage)) received or stored from NF or OAM (Operations, administration and management), etc. may be considered. If the request of the AMF 131 is an entire network slice, a network slice may be selected and candidate NFs included in the network slice may be selected in consideration of the overall state of the network slice. For example, if the network slice includes the AMF 131, the SMF 132, and the UPF 133, all of them may be included in the candidate NF. If the AMF request specifies a specific NF belonging to a network slice, candidate NFs having the corresponding NF Type may be selected. If the network slice is configured as an instance, one network slice instance may be selected. If there are several NF or Instances to be selected, the NF or Instance may be selected so that the load is distributed in consideration of the received maximum capacity and the current load state.

In step S315, the NSSF (134) in response to the network slice selection request (NSSelection Req) message from the AMF (131), including the network slice information in the network slice selection response (NSSelection Resp) message to the AMF (131). I can deliver. In this case, the network slice selection response may be implemented in the form of Nnssf_NSSelection Service, and may include authenticated network slice information (AuthorizedNetworkSliceInfo) including previously selected network slice information. For example, in the AuthorizedNetworkSliceInfo, if the request of the AMF 131 is an entire network slice, the network slice selection and candidate NFs included in the network slice may be included in consideration of the overall state of the network slice. If the network slice includes the AMF 131, the SMF 132, and the UPF 133, candidate information thereof may be included. If the request of the AMF 131 designates a specific NF belonging to a network slice, candidate NFs having a corresponding NF Type may be included. If the network slice is configured as an instance, it may include one slice instance. The information including the network slice may be configured in the form of a name or an identifier capable of identifying the selected network slice candidate or the selected instance. If the selection of the network slice capable of processing the request or the selection of NF fails, for example, when the allowable capacity of the corresponding network slice is exceeded, the NSSF 134 responds to the failure result, The reason may be included in the network slice selection response message and transmitted. Through this, the NSSF 134 may inform the AMF 131 of the reason why the selection of NF has failed. In particular, in the control according to the slice allowable quota in the present embodiment, a detailed reason (which value among the quota-the number of terminals/subscribers or the number of sessions-has reached the maximum value) may be reported.

In step S316, access control for a situation in which the maximum number of accessors (or terminals) among the quota of the slice is exceeded or the maximum number of sessions belonging to a specific slice is exceeded is considered. The AMF 131 may know that a corresponding condition has occurred in one or more of the slices for which the terminal 120 has requested access according to the slice information received in step S315.

In step S317, the AMF 131 transmits a response message to the registration request to the requested terminal 120. If access is allowed for the slice requested by the terminal 120 according to the subscription information, but the access is restricted due to a quota limit, or when access to one or more of the slices requested by the terminal 120 is possible, the response message is the terminal It may be a registration accept message. If the slice access is restricted due to the quota limit, the response message includes the rejected slice information, and the rejected slice information also has the reason for rejection and the connection is suspended due to the quota (number of slice visitors, number of slice sessions, etc.). (Pending) can be announced. In addition, during this process, the AMF 131 should store information on the requested slice and the slice for which access is suspended due to the quota limit for the corresponding terminal 120 as the terminal context.

In step S318, the terminal 120 receiving the registration response from the AMF 131 performs the remaining registration procedure. In addition, if the received response message includes information indicating that the connection is denied due to the quota limit for a specific slice(s) and the connection is suspended, the operation using the slice (transmission of traffic for the slice and PDU for this) is included. Session creation procedure) is suspended, and the corresponding operation cannot be performed until additional admission information is received from the network. Optionally, the terminal 120 is denied access to a specific slice(s) due to the quota limit per slice, notifies the upper layer that the connection has been suspended, the service application operates in consideration of this, or transmits an alarm to the user, etc. You can also have the action performed.

In step s319, if, during the above-described process, a connection is made possible in a predetermined slice among slices from which the connection has been suspended due to the slice quota limit (ie, transition to a connection state smaller than the quota of the slice), the stored UE Context Based on, it is possible to find whether there is a terminal on which the connection has been suspended, and to start an operation to inform the terminal that the connection is available.

In step S320, the AMF 131 may transmit information indicating that the slice access is possible for the terminal in which the connection has been suspended due to the slice quota limitation, but the slice access is possible to the terminal 120. At this time, the AMF 131 may notify the corresponding information using the UE configuration update process. At this time, in the NAS message, the identifiers (s-nassai) of the slices that were originally denied access in the pending state are included in the allowed slices (Allowed nassai), and that the slices whose access was suspended due to quota restrictions became available. An indicator to inform may be included. If the AMF 131 needs to be changed due to the update of the allowed slice, or if a separate registration procedure is required (if the service/movement allowable area needs to be changed, etc.), an indication that the registration procedure of the terminal 120 is required May be included.

In step S321, the terminal 120 through the message received from the AMF 131, it can be seen that the access to the slice (s) that was originally reserved for connection has become possible. Accordingly, the terminal 120 may perform necessary additional procedures, for example, a procedure such as creating a session for transmitting traffic through the corresponding slice, and also includes information indicating that a separate registration procedure is required in the received message. If so, the registration process can be carried out.

4 is a flowchart illustrating a procedure for performing access control for each network slice according to an embodiment of the present disclosure.

Referring to FIG. 4, a case in which the NSSF 134 provides information on a network slice is illustrated. However, it may be replaced with the NRF 153 or the SCP 157, the PCF 154 instead of the NSSF 134.

In step S410, the terminal 120 may transmit a connection request (RRC Connection (NSSAI)) message to the NG-RAN 110 by selecting a network slice to which it is to be accessed. The NG-RAN 110 in FIG. 4 is exemplified as an example of a base station and is not limited thereto. That is, the base station of FIG. 4 may be any base station among the various types of base stations described above.

In step S420, the base station (NG-RAN, 110) can select the AMF 131 using the network slice identifier specified by the terminal 120, the connection request message transmitted by the terminal 120, for example, N1 (NAS) message An initial UE message (Initial UE message-Registration Req (Requested NSSAI)) including a registration request may be delivered to the AMF 131 based on the (Registration request message described in the embodiment of the present disclosure).

In step S430, the AMF 131 may perform an operation for processing a registration request message transmitted from the terminal 120 through the base station 110. If the AMF 131 needs to receive subscription data for the terminal 120, it may receive subscription information from the UDM 155, and at this time, the access and mobility-related subscription information includes the terminal 120 This subscribed slice information (one or more Subscribed S-NSSAI) and basically usable slice information (one or more Default S-NSSAI) may be included. In addition, if it is difficult to access the slice requested by the terminal 120 or the access capacity is exceeded, the subscription information may include whether or not Slice Fallback is allowed to another slice.

In step S440, if a new network slice should be selected for the terminal 120, or a network slice should be changed, or a new AMF 131 belonging to the network slice should be selected, the network slice to the NSSF 134 A selection request (NSSelection Req) message can be transmitted. The network slice selection request (NSSelection Req) message may be performed through a GET operation of the Nnssf_NSSelection Service provided by the NSSF 134. At this time, information for slice selection may be requested not from NSSF (134), but from NRF (153), SCP (157), or PCF (154), and in this case, Service Operation for each NF is used, or AMF (131). ) Information stored inside may be used. When the AMF 131 transmits a network slice selection request (NSSelection Req) message, the AMF 131 provides network slice identifiers (Requested NSSAI) requested by the terminal 120, and network slice identifiers (subscribed NSSAI) included in the subscription information. It can be included in the slice selection request (NSSelection Req) message. In addition, when the AMF 131 transmits a network slice selection request (NSSelection Req) message, the AMF 131 notifies that the target of selection is all NFs included in the network slice, or a specific NF type in the network slice to be selected. Can be specified.

In step S450, the NSSF 134 may perform an operation for selecting a network slice according to the request of the AMF 131. At this time, information for each slice (maximum capacity per slice, current load (usage)) received or stored from NF or OAM may be considered. If the request of the AMF 131 is an entire network slice, a network slice may be selected in consideration of the overall state of the network slice, and candidate NFs included in the network slice may be selected. For example, if the network slice includes the AMF 131, the SMF 132, and the UPF 133, all of them may be included in the candidate NF. If the request of the AMF 131 designates a specific NF belonging to a network slice, candidate NFs having a corresponding NF Type may be selected. If the network slice is configured as an instance, one network slice instance may be selected. If there are several NF or Instances to be selected, the NF or Instance may be selected so that the load is distributed in consideration of the maximum capacity and the current load state.

In step S460, the NSSF (134) in response to the network slice selection request (NSSelection Req) message from the AMF (131), including the network slice information in the network slice selection response (NSSelection Resp) message to the AMF (131). I can deliver. In this case, the network slice selection response may be implemented in the form of Nnssf_NSSelection Service, and may include authenticated network slice information (AuthorizedNetworkSliceInfo) including previously selected network slice information. For example, in the AuthorizedNetworkSliceInfo, if the request of the AMF 131 is not limited to the AMF and is the entire network slice, the network slice is selected in consideration of the overall state of the network slice, and the identifier of the network slice instance or included in the network slice. Candidate NFs can be selected. If the network slice includes the AMF 131, the SMF 132, and the UPF 133, candidate information thereof may be included. If the request of the AMF 131 designates a specific NF belonging to a network slice, candidate NFs having a corresponding NF Type may be included. If the network slice is configured as an instance, one slice instance may be included. The information including the network slice may be configured in the form of a name or an identifier capable of identifying the selected candidate or the selected instance. If the selection of the network slice capable of processing the request or the selection of NF fails, for example, when the allowable capacity of the corresponding network slice is exceeded, the NSSF 134 responds to the failure result, The reason may be included in the network slice selection response message and transmitted. Through this, the NSSF 134 may inform the AMF 131 of the reason why the selection of NF has failed. In particular, in the control according to the slice allowable quota in the present embodiment, a detailed reason (which value among the quota-the number of terminals/subscribers or the number of sessions-has reached the maximum value) may be reported.

In step S470, access control for a situation in which the maximum number of accessors (or terminals) among the quotas of the slice is exceeded or the maximum number of sessions belonging to a specific slice is exceeded is considered. The AMF 131 may know that a corresponding condition has occurred in one or more of the slices requested by the terminal 120 according to the slice information received in step S460. At this time, the AMF 131 allows the terminal 120 to change to a basic slice and perform access. Accordingly, it is difficult to provide a service through the slice requested by the terminal 120, but the basic service through the basic slice is You can make it possible to provide.

In step S480, the AMF 131 transmits a response message to the registration request to the terminal 120. If access is allowed for the slice requested by the terminal 120 according to the subscription information, but the access is restricted due to a quota limit, or when access to one or more of the slices requested by the terminal 120 is possible, the response message is the terminal It may be a registration accept message. If the slice access is restricted due to the quota limit, and if the terminal 120 is induced to access by changing to another basic slice, the allowed slice of the response message (Allowed nssai) includes the allowed slice including the basic slice. An identifier is included, and an identifier of a rejected slice may be included in the rejected slice. In addition, this information may also inform that the reason for rejection is that the connection has been pending due to the limit of the quota (the number of sliced visitors, the number of sliced sessions, etc.). In addition, this message may additionally include an indication indicating that access to the slice requested by the UE is difficult, so that it is allowed to change to another slice and access. In addition, this message may include allowed DNN information indicating that the originally requested slice and the mapped DNN are available in the basic slice. In addition, this message may include a timer value to be used when determining whether to attempt to reconnect to a slice whose connection is temporarily suspended due to the maximum access limit of the quota. In addition, during this process, the AMF 131 should store information on the requested slice and the slice for which access is suspended due to the quota limit for the corresponding terminal 120 as the terminal context.

In step S490, the terminal 120 receiving the registration response from the AMF 131 performs the remaining registration procedure. If the received response message contains information indicating that a specific slice(s) has been denied due to the quota limit per slice and the connection has been suspended, the operation using the slice (transmitting traffic to the slice and creating a PDU session for this) Procedure) is suspended, and the terminal 120 cannot retry connection until the timer expires when additional admission information is received from the network or a retry timer is received. If the accepted message includes information indicating that the service through the basic slice is allowed, the terminal (!20) may receive the service through the basic slice instead. In addition, the terminal 120 selectively informs the upper layer that the connection is denied due to the quota limit per slice for a specific slice(s), and the connection is suspended, so that the service application operates in consideration of this or transmits an alarm to the user. have.

As shown in FIG. 3 described above, the AMF 131 may notify the terminal 120 when a slice access is possible, that is, steps S319 to S321 may also be applied to FIG. 4.

5 is a flowchart illustrating a procedure for providing a service by transitioning a terminal from a terminal to another access type according to an embodiment of the present disclosure.

Referring to FIG. 5, the NSSF 134 may provide information on a network slice. However, it may be replaced with the NRF 153 or the SCP 157, the PCF 154 instead of the NSSF 134.

In step S510, the terminal 120 may transmit an RRC Connection (NSSAI) message to the NR-RAN 110 by selecting an access type and a network slice to which the terminal 120 wishes to access. It should be noted that the NG-RAN 110 in FIG. 5 is exemplified as an example of a base station and is not limited thereto. That is, the base station may be any base station among the above-described types of base stations.

In step S520, the base station (NG-RAN, 110) can select the AMF 131 using the network slice identifier specified by the terminal 120, the connection request message transmitted by the terminal 120, for example, N1 (NAS) message An initial UE message (Initial UE message-Registration Req (Requested NSSAI)) including a registration request may be delivered to the AMF 131 based on the (Registration request message described in the embodiment of the present disclosure).

In step S530, the AMF 131 may perform an operation for processing a registration request message transmitted from the terminal 120 through the base station 110. If the AMF 131 needs to receive subscription data for the terminal 120, it may receive subscription information from the UDM 155, and at this time, the access and mobility-related subscription information includes the terminal to which the terminal is subscribed. Slice information (one or more Subscribed S-NSSAI), basically available slice information (one or more Default S-NSSAI), information of the allowed wireless network (Access Type) may be included, and additionally, if the slice requested by the terminal 120 When access is difficult or the access capacity is exceeded, whether it is allowed to fallback the terminal to a specific access network may be included.

In step S540, if a new network slice should be selected for the terminal 120, or a network slice should be changed, or when a new AMF 131 belonging to the network slice should be selected, the network slice to the NSSF 134 A selection request (NSSelection Req) message may be transmitted. The network slice selection request (NSSelection Req) message may be performed through a GET operation of the Nnssf_NSSelection Service provided by the NSSF 134. At this time, information for slice selection may be requested not from NSSF (134), but from NRF (153), SCP (157), or PCF (154). In this case, service operation for each NF is used, or AMF (131) Information stored internally may be used. When transmitting a network slice selection request (NSSelection Req) message, the AMF 131 selects the network slice identifiers (Requested NSSAI) and network slice identifiers (subscribed NSSAI) included in the subscription information requested by the terminal 120 to the network slice. It can be included in the request (NSSelection Req) message. In addition, when transmitting a network slice selection request (NSSelection Req) message, the AMF 131 may notify that the target of selection is all NFs included in the network slice, or may designate a specific NF Type in the network slice to be selected.

In step S550, the NSSF 134 may perform an operation for selecting a network slice according to the request of the AMF 131. At this time, information for each slice (maximum capacity per slice, current load (usage)) received or stored from NF or OAM may be considered. If the request of the AMF 131 is an entire network slice, a network slice may be selected and candidate NFs included in the network slice may be selected in consideration of the overall state of the network slice. For example, if the network slice includes the AMF 131, the SMF 132, and the UPF 133, all of them may be included in the candidate NF. If the request of the AMF 131 designates a specific NF belonging to a network slice, candidate NFs having a corresponding NF Type may be selected. If the network slice is configured as an instance, one network slice instance may be selected. If there are multiple NFs or instances to be selected, the NF or Instance may be selected so that the load is distributed in consideration of the received maximum capacity and the current load state.

In step S560, the NSSF (134) in response to the network slice selection request (NSSelection Req) message from the AMF (131), including the network slice information in the network slice selection response (NSSelection Resp) message to the AMF (131). I can deliver. In this case, the network slice selection response may be implemented in the form of an Nnssf_NSSelection Service, and may include authenticated network slice information (AuthorizedNetworkSliceInfo) including information on a previously selected network slice. For example, in the AuthorizedNetworkSliceInfo, if the request of the AMF 131 is an entire network slice, a network slice may be selected in consideration of the entire state of the network slice, and candidate NFs included in the network slice may be selected. If the network slice includes the AMF 131, the SMF 132, and the UPF 133, the AMF 131, the SMF 132, and the UPF 133 may include their candidate information. If the request of the AMF 131 designates a specific NF belonging to a network slice, slice information included in the response message may include candidate NFs corresponding to the corresponding NF Type. If the network slice is configured as an instance, the instance may include one slice instance. The information including the network slice may be configured in the form of a name or an identifier capable of identifying the selected candidate or the selected instance. If the selection of a network slice capable of processing a request or selection of an NF fails, for example, when the allowable capacity of the corresponding network slice is exceeded, the NSSF 134 results in a corresponding failure. , The reason may be included in the network slice selection response message and transmitted. Through this, the NSSF 134 may inform the AMF 131 of the reason why the selection of NF has failed. In particular, the NSSF 134 may inform the detailed reason (what value of the quota-the number of terminals / subscribers or the number of sessions-has reached the maximum value) in the control according to the slice allowable quota.

In step S570, access control for a situation in which the maximum number of accessors (or terminals) among the quota of the slice is exceeded or the maximum number of sessions belonging to a specific slice is exceeded is considered. The AMF 131 may know that a corresponding condition has occurred in one or more of the slices for which the terminal 120 has requested access, according to the slice information received in step S560. At this time, the AMF 131 allows the terminal 120 to perform access to another RAT (Radio Access Technology), which provides a service through a slice requested from the RAT for which the terminal 120 currently requests access. Although this is difficult, it is intended to be able to provide basic services through other RATs.

In step S580, the AMF 131 transmits a response message to the registration request to the requested terminal 120. If access is restricted due to quota restrictions for all slices requested by the terminal 120, this message may be a terminal rejection (Registration REJECT) message. If access to a slice is restricted due to a quota limit, the rejected slice includes the identifier of the rejected slice, and this information also indicates that the reason for rejection is due to the quota (number of slice visitors, number of slice sessions, etc.). It may include that the connection has been denied. In addition, this message may include an indication indicating that access is induced through a specific RAT. In addition, this message may include a timer value to be used when deciding whether to attempt to reconnect to a slice and a current RAT whose access is rejected due to the maximum access limit of the quota. In addition, during this process, the AMF 131 should store information on the requested slice and the slice for which access is suspended due to the quota limit for the corresponding terminal 120 as the terminal context.

On the other hand, inducing access to a specific RAT to the terminal 120 may be notified by the AMF 131 directly to the terminal 120 through a NAS response as described above. In addition, in another embodiment, the AMF 131 in the message sent to the NG-RAN 110, for a specific RAT for the terminal 120 (in this embodiment, another RAT to allow access when the slice capacity is exceeded) Include information (RFSP Index or SPID) that induces to increase the access priority, and the NG-RAN 110 receiving it changes the radio access setting of the terminal 120 to increase the access priority of a specific RAT. You may.

In step S590, if the terminal 120 receiving the registration response from the AMF 131 includes information to access and operate with a specific RAT in the response message, it may transition to the corresponding RAT and perform an operation for receiving the service. have. If the retry timer is received in the message received from the AMF 131, the terminal 120 cannot retry the registration request for the slice rejected by the original RAT until the timer expires. If the timer expires, the terminal 120 may try to request registration for a corresponding slice by changing the RAT again. In addition, the terminal 120 selectively informs the upper layer that access is denied due to the quota limit per slice for a specific slice(s), and RAT change occurs, so that the service application operates in consideration of this or transmits an alarm to the user. The motion of the back may be induced.

In this embodiment, as shown in FIG. 3 described above, when a slice access is possible, this may be notified to the terminal 120, that is, steps S319 to S321 may also be applied to an embodiment of the present disclosure. If the system to which the terminal 120 is connected is changed to 4G instead of 5G by the above-described operation, the MME (not shown) indicates that a specific slice is available is 5G such as the AMF 131 or UDM 155. It may be received from the NF, and may be replaced by a message forwarded from the MME other than the AMF 131 to the terminal 120. In addition, the terminal 120 may additionally perform an operation of changing the RAT before performing the registration process.

6 is a diagram illustrating a configuration of a terminal according to an embodiment of the present disclosure.

As shown in FIG. 6, the terminal of the present disclosure may include a transceiver 610, a memory 620, and a processor 630. The processor 630, the transceiver 610, and the memory 620 of the terminal may operate according to the above-described communication method of the terminal. However, the components of the terminal are not limited to the above-described example. For example, the terminal may include more or fewer components than the above-described components. In addition, the processor 630, the transceiver 610, and the memory 620 may be implemented in the form of a single chip.

The transceiving unit 610 refers to a receiving unit of a terminal and a transmitting unit of a terminal, and may transmit and receive signals with a base station. Signals transmitted and received with the base station may include control information and data. To this end, the transceiver 610 may include an RF transmitter that up-converts and amplifies a frequency of a transmitted signal, and an RF receiver that amplifies a received signal with low noise and down-converts a frequency. However, this is only an embodiment of the transmission/reception unit 610, and components of the transmission/reception unit 610 are not limited to the RF transmitter and the RF receiver.

In addition, the transmission/reception unit 610 may receive a signal through a wireless channel, output it to the processor 630, and transmit a signal output from the processor 630 through a wireless channel.

The memory 620 may store programs and data required for the operation of the terminal. In addition, the memory 620 may store control information or data included in a signal obtained from the terminal. The memory 620 may be composed of a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

The processor 630 may control a series of processes so that the terminal can operate according to the above-described embodiment of the present disclosure. The processor 630 may include at least one or more processors. For example, the processor 630 may include a communication processor (CP) that controls communication and an application processor (AP) that controls an upper layer such as an application program.

7 is a diagram illustrating a configuration of a network entity according to an embodiment of the present disclosure.

As shown in FIG. 7, the network entity of the present disclosure may include a transceiver 710, a memory 720, and a processor 730. According to the above-described communication method of the network entity, the processor 730, the transceiver 710, and the memory 720 of the network entity may operate. However, the constituent elements of the network entity are not limited to the above-described example. For example, the network entity may include more or fewer components than the above-described components. In addition, the processor 730, the transceiver 710, and the memory 720 may be implemented in the form of a single chip. Network entities, such as AMF (Access and Mobility Management Function), SMF Session Management Function), PCF (Policy and Charging Function), NEF (Network Exposure Function), UDM (Unified Data Management), UPF (User Plane Function), etc. It may include a network function (NF). It may also include a base station.

The transmission/reception unit 710 collectively refers to a reception unit of a network entity and a transmission unit of a network entity, and may transmit and receive signals with a terminal or other network entity. In this case, the transmitted/received signal may include control information and data. To this end, the transceiver 710 may include an RF transmitter that up-converts and amplifies a frequency of a transmitted signal, and an RF receiver that amplifies a received signal with low noise and down-converts a frequency. However, this is only an embodiment of the transmission/reception unit 710, and components of the transmission/reception unit 710 are not limited to the RF transmitter and the RF receiver. The transceiving unit 710 may include a wired/wireless transceiving unit, and may include various components for transmitting and receiving signals.

In addition, the transmission/reception unit 710 may receive a signal through a communication channel (eg, a wireless channel), output it to the processor 730, and transmit a signal output from the processor 730 through a communication channel.

The memory 720 may store programs and data necessary for the operation of the network entity. In addition, the memory 720 may store control information or data included in a signal obtained from a network entity. The memory 720 may be composed of a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

The processor 730 may control a series of processes so that the network entity can operate according to the above-described embodiment of the present disclosure. The processor 730 may include at least one or more processors.

8 is another diagram showing the configuration of a network entity according to an embodiment of the present disclosure.

The network entity of FIG. 8 may correspond to the configuration of the network entity described above in FIG. 7. Referring to FIG. 8, the network entity includes an NF, and the NF is an AMF 131 and an SMF 132 as described above. , UPF (133) may be included. In addition, NF may include NSSF (134), NFR (153), and SCP (157). As another example, NF may be implemented as a separate network entity.

Referring to FIG. 8, the network interface 810 may communicate with other network entities of the core network. For example, when the NF is the AMF 131, communication with the SMF 132, the UPF 133, the NSSF 134, the NFR 153 or/and the SCP 157 may be performed. As another example, when the NF is the SMF 132, communication with the AMF 131, the UPF 133, the NSSF 134, the NFR 153, or/and the SCP 157 may be performed. In another case, when the NF is the NSSF 134, communication with the AMF 131, the UPF 133, the SMF 132, the NFR 153, or/and the SCP 157 may be performed. Similarly, if the NF is one specific network entity, it can communicate with other entities in the core network.

The control unit 811 may be implemented as at least one processor or/and a program for performing the operation of the NF. For example, when the NF is the AMF 131, the controller 811 may perform the operation of the AMF 131 described above. As another example, when the NF is the NSSF 134, the above-described operation of the NSSF 134 may be performed. In the case of other network entities, control necessary for the above-described operation can be performed in the same manner.

The memory 812 may store programs required by the controller 811 and various types of control information, as well as each information described in the present disclosure. For example, when the NF is the AMF 131, the memory 812 may store information received from the AMF 131 described above or received from an external entity. As another example, when the NF is the NSSF 134, the necessary control information or/and received information from the above-described NSSF 134 may be stored. In the case of other network entities, information necessary for the operation described above may be stored in the same manner.

9 is a diagram illustrating an operation of a terminal and a network according to an embodiment of the present disclosure.

In step 1, the terminal transmits a registration request message for requesting use of a specific slice to the AMF. This message includes Requested NSSAI, which is a set of identifiers (S-NSSAIs) of the target slice for which the terminal requests permission to use. This message includes information indicating whether the terminal supports the functions for quota management per slice (cause reception, back-off timer use, rejected/pending NSSAI processing, etc.) or whether gst (generic network slice template)-based slice control function is supported. This may be included as part of the 5G mobility management (5GMM) capability of the registration request.

In step 2, if there is a slice to be managed for Quota (the maximum number of concurrently connected terminals/subscribers) among the slices of the network, the current state of the slice (the current state of the number of concurrently connected terminals/subscribers per slice or the current slice Whether or not additional terminals/subscribers can be accommodated/disallowed, etc.) can be identified. This may be achieved by exchanging information between the NF and AMF, which manages the quota of the slice in the network (or counts the number of access terminals/subscribers of the slice). That is, the NF that manages Qouta (eg, Slice Quota management. or Counting nf) collects the number of terminals for each slice currently registered from other NFs (AMF, etc.) of the network, and is set for each slice by comprehensively considering this. It can be determined whether the limit of the maximum number of simultaneous access terminals has been reached. The slice quota management NF is AMF, and information of the slice (one or more of the total number of connected terminals per slice, the maximum number of concurrently connected terminals for a slice, whether a new terminal access of the current slice is possible, or whether the upper limit of the slice's quota has been reached) , When limiting slice access, a parameter to be used (cause value, preferred back-off timer) can be determined and delivered. Step 2 and Step 1 may operate independently of each other or may occur in a reverse order.

In step 3, the AMF may process the registration request of the terminal. If a slice identified by S-NSSAI included in the Requested NSSAI requested by the terminal is checked if there is a slice whose quota (the maximum number of concurrently connected terminals/subscribers) is the management target, the current slice is It can be determined whether slice registration is allowed according to the state. The parameters set by the AMF to control the UE in this operation and in the following steps may be applied only when the UE notifies that the UE supports Quota-based slice control or GST-based slice control function in Step 1.

In step 4, if the slice quota reaches the upper limit or if the slice access is to be restricted, the AMF informs the registration response (registration accept or registratoin reject) message sent to the terminal with information related to the access restriction according to the quota management for each slice. Can include. When access to a slice corresponding to at least one of the S-NSSAIs included in the NSSAI requested by the terminal is restricted, the AMF may operate by selecting one of the following three options.

Option 1) The AMF may include identifiers (S-NSSAIs) corresponding to slices for which access is restricted because the slice quota reaches the upper limit in the rejected NSSAI. An identifier indicating whether the rejected NSSAI is rejected by the entire PLMN or by a current registration area (RA) can be set. A cause indicating that the request has been rejected because the slice Quota (the maximum number of concurrently accessible terminals) has reached an upper limit may be set. In addition, a back-off timer value for limiting the registration request for the corresponding slice of the terminal may be set. The back-off timer value may be received in step 2, may be determined by subscription information (different according to the subscriber's subscription level or priority), or AMF internal settings, and different values may be set for each S-NSSAI. . The above-described parameters may be included in a registration response (accept or reject) message sent to the terminal. In particular, when access is restricted to all S-NSSAIs requested by the terminal, the response message may be a registration reject message.

Option 2) The AMF may include identifiers (S-NSSAIs) corresponding to slices for which access is restricted because the slice quota reaches the upper limit in the pending NSSAI. A cause indicating that the request has been pending may be set because the slice Quota (the maximum number of concurrently accessible terminals) has reached an upper limit. A back-off timer value for limiting the registration request for the corresponding slice of the terminal may be set. The back-off timer value may be received in step 2, may be determined by subscription information (different according to the subscriber's subscription level or priority), or an internal setting of the AMF, and different values may be set for each S-NSSAI. . The above-described parameters may be included in a registration response (accept or reject) message sent to the terminal.

Option 3) The AMF may set a cause indicating that the request has been pending because the slice quota (the maximum number of concurrently accessible terminals) has reached the upper limit. A back-off timer value and a target S-NSSAI for limiting the registration request for the corresponding slice of the terminal may be set. The back-off timer value may be received in step 2, may be determined by subscription information (different according to the subscriber's subscription level or priority), or AMF internal settings, and different values may be set for each S-NSSAI. . The above-described parameters may be included in a registration response (accept or reject) message transmitted to the terminal.

The AMF may store the information (rejected or pending NSSAI and associated cause, back-off timer value) as the context of the terminal.

In step 5, the terminal may store the information received from the AMF through the registration response message in step 4. If the message received by the terminal includes a reason notifying that the slice access is restricted due to the quota limit of the slice, and the back-off timer value is included, the terminal starts a back-off timer and back-off Until the timer expires, registration request cannot be initiated for the relevant S-NSSAI in the plmn. The UE cannot stop or cancel the timer even when cell change, RAT change, plmn change, or access type change. The operation of the terminal according to the option of step 4 may be different. Hereinafter, the operation of the terminal according to the options 1 to 3 will be described.

Option 1) When the terminal receives the rejected NSSAI due to the slice quota limitation, if the target of the rejected NSSAI is the entire PLMN, the terminal is allowed to perform a registration request for the S-NSSAI included in the NSSAI in the entire plmn. It doesn't work. In addition, if the object to which the rejected NSSAI is applied is the registration area (RA), the registration request is not permitted within the RA, but other RAs may perform the registration request. When the terminal receives the rejected NSSAI due to the slice quota limitation, when the back-off timer associated with the S-NSSAI expires, the corresponding S-NSSAI may be deleted from the rejected NSSAI. Thereafter, the terminal may initiate a registration request for permission to use the corresponding slice (S-NSSAI).

Option 2) When the terminal receives the pending NSSAI due to the slice quota limitation, if the target of the NSSAI is the entire PLMN, the terminal is not allowed to perform a registration request for the S-NSSAI included in the NSSAI in the entire plmn. In addition, if the target of the NSSAI is an RA, the registration request is not permitted within the RA, but other RAs can perform the registration request. When the terminal receives the pending NSSAI due to the slice quota limitation, when the back-off timer associated with the S-NSSAI expires, the corresponding S-NSSAI may be deleted from the pending NSSAI. Thereafter, the terminal may initiate a registration request for permission to use the corresponding slice (S-NSSAI).

Option 3) If the terminal receives the back-off timer value associated with the S-NSSAI due to the slice quota limit, it cannot perform the registration request related to the S-NSSAI while the timer is running, and after the timer expires. You can initiate a registration request for permission to use the slice (S-NSSAI).

From step 6, it can occur selectively after the previous step. That is, it may not be performed after step 6.

Step 6) The AMF may determine whether a new connection is possible for at least one or more of the slices for which the new terminal access is not allowed due to the quota restriction. This may be accomplished by receiving the slice state information as in step 2 described above.

Step 7) The AMF may transmit an access request to a slice in which access is possible, and may transmit information notifying that the slice is available for use to a terminal in a pending state. If a maritime slice is included in the pending NSSAI for a specific terminal, the AMF may change the slice into the allowed NSSAI to be used. As another method, the AMF may transmit a reason or an indicator indicating that a request for access to a slice is possible while maintaining the pending NSSAI state for the terminal. Alternatively, AMF may set the value of the back-off timer of the slice to 0 and send this value. The message used in step 7 may be a registration response message if the terminal sends a registration request, and a UE configuration update message otherwise.

Step 8) The terminal may update the state of the slice through a message received from the AMF. If some slices included in the pendging NSSAI through step 7 are included in the allowed NSSAI, the terminal may determine that the use of the corresponding slice is permitted. If the reason for the slice included in the pending NSSAI or the indicator informs that a slice access request is available, the terminal may terminate the back-off timer for the slice and perform a registration request for the slice. have. If the terminal receives a back-off timer value of 0 for some slices, it may set the timer value to 0 or terminate the timer and perform a registration request for the corresponding slice.

The methods according to the embodiments described in the claims or the specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in a computer-readable storage medium are configured to be executable by one or more processors in an electronic device (device). The one or more programs include instructions for causing the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

Such programs (software modules, software) include random access memory, non-volatile memory including flash memory, read only memory (ROM), and electrically erasable programmable ROM. (electrically erasable programmable read only memory, EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs) or other forms of It may be stored in an optical storage device or a magnetic cassette. Alternatively, it may be stored in a memory composed of a combination of some or all of them. In addition, a plurality of configuration memories may be included.

In addition, the program is a communication network such as the Internet (Internet), Intranet (Intranet), LAN (local area network), WAN (wide area network), or SAN (storage area network), or a communication network composed of a combination thereof. It may be stored in an accessible storage device. Such a storage device may access a device performing an embodiment of the present disclosure through an external port. In addition, a separate storage device on the communication network may access a device performing an embodiment of the present disclosure.

In the above-described specific embodiments of the present disclosure, components included in the disclosure are expressed in the singular or plural according to the presented specific embodiments. However, the singular or plural expression is selected appropriately for the situation presented for convenience of description, and the present disclosure is not limited to the singular or plural constituent elements, and even constituent elements expressed in plural are composed of the singular or in the singular. Even the expressed constituent elements may be composed of pluralities.

Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, various modifications may be made without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure is limited to the described embodiments and should not be determined, and should be determined by the scope of the claims and equivalents as well as the scope of the claims to be described later.

Claims (1)

In a method for controlling a network slice by an Access and Mobility Management Function (AMF),
Transmitting a request for selecting the network slice;
Receiving a candidate of the network slice for the selection request;
Determining a quota of the received network slice candidate; And
Including, controlling whether a user terminal is connected to the network slice candidate based on the determined quota.

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