KR20190043084A - Method and apparatus for location based service in 5g system - Google Patents

Abstract

A location reporting method comprises: a step of transmitting, by an apparatus with an access and mobility management function (AMF), a location reporting control message requesting a location of a user terminal through an access network; and a step of receiving a location report message according to the location reporting control message from the access network, wherein the location reporting control message can include requested location information or a reporting type.

Description

[0001] METHOD AND APPARATUS FOR LOCATION BASED SERVICE IN 5G SYSTEM [0002]

The following embodiments relate to a 5G system device and method for supporting location based services.

A Mobile Edge Computing (MEC) technique has been proposed to provide a low-latency data service in a user equipment (UE). The MEC technique is used to minimize the Round Trip Time (RTT) between the UE and the server providing the service requested by the UE. The MEC technique relates to a technique for locating a geographical location of a server close to a UE, as well as reducing the number of routing hops between the UE and the server.

The 5G mobile communication network requires that various services be provided to the UE via 5G network technology. Accordingly, the 5G mobile communication network also supports edge computing technology to provide improved quality of service over existing network schemes.

According to one embodiment, if a terminal is in the CM-CONNECTED state and there is a LADN service session in the base station, the 5G core network may propose to perform a location report request to the base station.

According to an exemplary embodiment, a location reporting method performed by an AMF apparatus includes a location report control message requesting location of a user terminal in an Access and Mobility Management Function (AMF) (Location Reporting Control message); And receiving a location report message according to the location report control message from the access network, wherein the location report control message includes a requested location information or a reporting type, ).

The requested location information may be a location reporting method performed by the AMF device, which is a TAI (Tracking Area Identifier) + cell ID.

Wherein the reporting type indicates whether the location report control message is for i) triggering a single standalone report on the current cell ID serving the user terminal, or ii) To indicate whether the access network is for initiating a location report each time, or iii) whether to report to the access network whenever the user terminal moves into or out of an area of interest , A location reporting method performed by the AMF device.

When the reporting type is iii) to request a report to the access network whenever the user terminal moves inside or outside the ROI, the AMF device transmits information about the ROI requested through the location report control message And a location reporting method performed by the AMF device, including the step of providing the location information.

The AMF device may further comprise a location reporting method performed by the AMF device, the method further comprising transmitting a Cancel Location Reporting message to the access network.

The cancel position report message may be a location report method performed by the AMF apparatus, which indicates the end of the location report for the user terminal.

The cancel position reporting message may be a location reporting method performed by the AMF apparatus when the location report is requested for a predetermined period of time.

Wherein when the location report control message indicates the single independent report and the user terminal is CM-CONNECTED in an RRC Inactive state, the access network performs RAN paging before reporting the location to the AMF device , A location reporting method performed by the AMF device.

Wherein the location report control message indicates a persistent location report each time the user terminal changes a cell, and if the user terminal is CM-CONNECTED in an RRC active state, a time stamp from the access network, And receiving a location report message including the last known location of the user terminal with the location information of the user terminal.

Wherein the reporting type is configured such that if the location report control message requests location reporting to the access network each time the user terminal moves into or out of the ROI, The AMF apparatus may be a location reporting method performed by the AMF apparatus that receives the location report message including the location of the user terminal.

According to one embodiment, an Access Network receives a Location Reporting Control message requesting the location of a user terminal from an Access and Mobility Management Function (AMF) ; And transmitting a location report message according to the location report control message to the AMF device, wherein the location report control message includes a requested location information or a reporting type, , Which may be a location reporting method performed by the access network.

The requested location information may be a location reporting method performed by the access network, which is a Tracking Area Identifier (TAI) + cell ID.

Wherein the reporting type indicates whether the location report control message is for i) triggering a single standalone report on the current cell ID serving the user terminal, or ii) To indicate whether the access network is for initiating a location report each time, or iii) whether to report to the access network whenever the user terminal moves into or out of an area of interest , A location reporting method performed by the access network.

When the reporting type is iii) to request a report to the access network every time the user terminal moves into or out of the ROI, the access network transmits, from the AMF device, And receiving information about the location of the access network.

The access network may be a location reporting method performed by the access network, further comprising receiving from the AMF device a Cancel Location Reporting message.

The cancel location report message may be a location report method performed by the access network indicating an end of location report for the user terminal.

The cancel location report message may be a location reporting method performed by the access network, which is transmitted when the location report is requested for a certain period of time.

According to one embodiment, a Session Management Function (SMF) determines a region of interest and provides it to an access and mobility management functional device; And receiving a new location of the user terminal from the AMF device, depending on whether the user terminal has moved into or out of the area of interest, wherein the area of interest comprises an SMF And may be a UE Location Change Notification method performed by the UE.

The SMF device subscribes to a "UE mobility event notification" service provided by the AMF device, and the service subscription is maintained during the life of the PDU session. .

The SMF device may further comprise means for performing a UPF relocation or releasing a PDU session, or iii) deactivating a User Plane Connection for a PDU session as soon as the new location of the user terminal is received, And may be a user terminal location change notification method performed by the device.

The SMF device may be a method of notifying a user terminal location change performed by the SMF device, which determines a new area of interest according to the new location.

The SMF device may be a user terminal location change notification method performed by the SMF device, which unsubscribes the " UE mobility event notification " service when a PDU session is released.

According to one embodiment, an access and mobility management function (AMF) detects whether a user terminal has moved into or out of a region of interest; And notifying the AMF device of a new location of the user terminal to a Session Management Function (SMF) device, wherein the area of interest is determined based on a UPF service area, User terminal location change notification method.

The SMF device subscribes to a "UE mobility event notification" service provided by the AMF device, and during the service subscription, the SMF device determines the area of interest and provides it to the AMF device. The terminal location change notification method.

The service subscription may be a user terminal location change notification method performed by the AMF device, which is maintained during the lifetime of the PDU session.

According to one embodiment, a memory including a processor and computer readable instructions is included in an Access and Mobility Management Function (AMF), and when the instructions are executed in the processor, Transmits a Location Reporting Control message requesting the location of the user terminal to an access network and receives a Location Report message according to the location report control message from the access network And the location report control message may be an Access and Mobility Management Function (AMF) including requested location information or a reporting type.

According to one embodiment, an access network includes a processor and a memory that includes instructions readable by the computer, and when the instructions are executed on the processor, the access network comprises an Access and Mobility Management Function Receiving a Location Reporting Control message requesting the location of the user terminal from the AMF, transmitting a Location Report message according to the location report control message to the AMF device, The reporting control message may be an access network, including requested location information or reporting type.

According to one embodiment, a session management function (SMF) includes a processor and a memory including instructions readable by the computer, and when the command is executed in the processor, the SMF device And receiving the new location of the user terminal from the AMF device according to whether the user terminal has moved into or out of the ROI, Area, which is determined based on the area.

According to one embodiment, a memory including a processor and computer readable instructions is included in an Access and Mobility Management Function (AMF), and when the instructions are executed in the processor, Detects whether the user terminal has moved into or out of the ROI, notifies the new location of the user terminal to a Session Management Function (SMF) device, and the ROI is based on the UPF service area And may be an access and mobility management device.

According to an embodiment of the present invention, when a terminal is in a CM-CONNECTED state and there is a LADN service session in the base station, the 5G core network may propose to perform a location report request to the base station.

Figure 1 illustrates a RM (Registration Management) state model of a user terminal according to an embodiment.
2 illustrates an RM state model of an AMF device according to one embodiment.
FIG. 3 illustrates a CM state transition at a user terminal according to an exemplary embodiment.
Figure 4 illustrates the CM state transition in an AMF device according to one embodiment.
5 illustrates, in accordance with one embodiment, the four cases illustrate the relationship between the registration area and the area of interest.
6 shows an N4 session establishment procedure according to an embodiment.
7 illustrates an N4 session modification procedure according to an embodiment.
8 shows an N4 session release procedure according to one embodiment.
9 shows an N4 reporting procedure according to one embodiment.
10 is a diagram illustrating a procedure for changing the SSC mode 2 PSA for a PDU session according to an exemplary embodiment.
11 is a diagram illustrating a procedure for changing an SSC mode 3 PDU session anchor having a plurality of PDU sessions according to an embodiment.
12 is a diagram illustrating a user terminal configuration update procedure according to an embodiment.
13 is a diagram illustrating a procedure for requesting a user terminal reachability notification according to an embodiment.
14 is a diagram illustrating a user terminal activity procedure, in accordance with one embodiment.
15 is a diagram illustrating a location reporting procedure according to an embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. Like reference symbols in the drawings denote like elements.

Various modifications may be made to the embodiments described below. It is to be understood that the embodiments described below are not intended to limit the embodiments, but include all modifications, equivalents, and alternatives to them.

The terms first or second may be used to describe various components, but such terms should be understood only for the purpose of distinguishing one component from another. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terms used in the examples are used only to illustrate specific embodiments and are not intended to limit the embodiments. The singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this embodiment belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

In the following description of the present invention with reference to the accompanying drawings, the same components are denoted by the same reference numerals regardless of the reference numerals, and redundant explanations thereof will be omitted. In the following description of the embodiments, a detailed description of related arts will be omitted if it is determined that the gist of the embodiments may be unnecessarily blurred.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Definitions>

- 5G Access Network: An access network that includes NG-RAN and / or non-3GPP AN connecting to a 5G core network.

- 5G Core Network: Connected to 5G access network.

- 5G System: 3GPP system consisting of 5G access network, 5G core network and user terminal.

- Allowed Area: The area where the user terminal can start communication.

- AMF Region: AMF region consisting of one or more AMF sets.

- Forbidden area: An area where the user terminal does not start to initiate communication.

- Initial Registration: Registration of user terminal in RM-DEREGISTERED state

- Local Area Data Network: DN where the UE is accessible at a specific location, provides a connection to a specific DNN, and is provided with the UE's availability.

- Mobility pattern: A network concept that determines the UE mobility parameters within the NF.

- Mobility Registration update: UE re-registration when entering a new TA (Tracking Area) outside the Tracking Area Identifier (TAI) list.

- NG-RAN: A wireless access network that supports one or more of the following options with common characteristics connected to a 5G core network: 1) Standalone new wireless 2) New wireless anchor with E-UTRA extension 3) Standalone E- UTRA 4) E-UTRA is anchor with new wireless extension

- Non-allowed area: The area where the UE can initiate the registration procedure, but no other communication can start.

- PDU Session (Protocol Data Unit Session): The association between the data network providing the PDU connection service and the user terminal.

- PDU Connectivity Service: A service that provides exchange of PDUs between a user terminal and a data network.

- PDU Session Type: The type of PDU session that can be IPv4, IPv6, Ethernet or Unstructured.

- Periodic Registration update: UE re-registration when periodic registration timer expires

- Service Continuity: Unobtrusive user experience, including changes in IP address and / or anchor point.

- Session Continuity: The continuity of the PDU session. For the IPv4 or IPv6 type PDU session, "session continuity" means that the IP address is held for the lifetime of the PDU session.

Uplink Classifier: A UPF function that diverts uplink traffic toward the data network based on the filter rules provided by the SMF device.

<Abbreviations>

- 5GC: 5G Core Network (5G Core Network)

- 5GS: 5G system (5G System)

- 5G-AN: 5G Access Network (5G access network)

- 5G-GUTI: 5G Globally Unique Temporary Identifier

- AMF: Access and Mobilty Management Function (Access and Mobilty Management Function)

- AUSF: Authentication Server Function

- CP: Control Plane

- DL: Downlink (Downlink)

- DN: Data Network

- DNN: Data Network Name

- HR: Home Routed (roaming)

- LADN: Local Area Data Network

- MICO: Mobile Initiated Connection Only

- N3IWF: Non-3GPP Inter Working Function

- NAI: Network Access Identifier

- NF: Network function

- NR: New Radio

- NEF: Network Exposure Function

- NRF: Network Repository Function

- PCF: Policy Control Function

- PSA: PDU Session Anchor (PDU Session Anchor)

- (R) AN: (Radio) Access Network (Radio Access Network)

- SSC: Session and Service Continuity

- SUCI: Subscription Concealed Identifier

- SUPI: Subscription Permanent Identifier

- UL: Uplink

- UL CL: Uplink Classifier

- UPF: User Plane Function

- UDR: Unified Data Repository

The Session Management Function (SMF), the Access and Mobility Management Function (AMF), and the User Plane Function (UPF) described below are software functions, And may be installed or executed on each of a plurality of hardware.

<Concepts>

The 5G system architecture is defined to support data connectivity and services using technologies such as Network Function Virtualization (NFV) and Custom Networking (SDN). The 5G system architecture should utilize the service-based interactions between the control plane network functions where identified. Some key principles and concepts of the 5G system architecture are:

I) Separating the user plane (UP) function from the control plane (CP) function allows for independent scalability, evolution and flexible placement. For example, in a centralized or distributed (remote) location. Ii) Modularizing the functional design. For example, flexible and efficient network slicing is possible. Iii) If applicable, reuse may be possible by defining the procedure as a service (eg, a set of interactions between network functions). Iv) If necessary, each network function can directly interact with other NFs. The architecture does not preclude the use of intermediate functionality to help route control plane messages. V) Minimizing the dependency between the access network (AN) and the core network (CN). The architecture is defined as a core network with a common AN-CN interface that integrates different access types. Vi) Supports the integrated authentication framework. Ⅶ) Supports "stateless" NFs where "computation" resources are separate from "storage" resources. Ⅷ) Supports capability exposure. Ⅸ) Supports concurrent access to local and centralized services. To support low latency services and access to the local data network, the UP functions may be placed near the access network. X) Supports both local breakout traffic and home routing traffic in visited PLMNs.

<Architecture Reference Model>

Describes the architecture of the 5G system. The 5G architecture is defined as a service base, and the interaction between network functions is expressed in two ways:

I) A network-based function (eg, AMF) in the control plane is a service-based representation that allows other authenticated network functions to access the service. These service-based representations include point-to-point reference points as needed. Ii) The reference point representation is the interaction between the NF services in the network function described by the reference point (e.g., N11) between the points between any two network functions (e.g., AMF and SMF) .

<Service-based interface>

The 5G system architecture includes the following service-based interfaces:

I) Namf: a service based interface exhibited by AMF ii) Nsmf: a service based interface displayed by SMF iii) Nnef: a service based interface exhibited by NEF iv) Npcf: a service based interface displayed by PCF Service interface based on NFS: Service-based interface displayed by NFS: Service-based interface displayed by NFS: Service-based interface displayed by NF: Service-based interface displayed by NFS: ) Nausf: Service-based interface exhibited by AUSF ⅹ) Nudr: Service-based interface exhibited by UDR ⅹ i) Nudsf: Service-based interface exhibited by UDSF

<Reference Points>

The 5G system architecture includes the following reference points:

2) N2: Reference point between the access network and the AMF device. 3) N3: Reference point between the access network and the UPF device. 4) N4: Reference point between the SMF device and the UPF device. 5) N6: Reference point between UPF device and data network. 6) N9: Reference point between UPF device s.

The following reference points represent the interactions existing between the NF services of the NFs. These reference points are realized by a corresponding NF service based interface and are realized by designating the interaction as well as the identified consumer and producer NF services to realize a particular system procedure.

1) N5: Reference point between PCF and AF 2) N7: Reference point between SMF device and PCF 3) N8: Reference point between UDM and AMF device 4) N10: Reference point between UDM and SMF device 5) N11: Reference point between SMF devices. 6) N12: Reference point between AMF device and AUSF. 7) N14: Reference point between AMF devices.

<Support of Non-3GPP>

The 5G core network supports connectivity of the UE over a Non-3GPP access network, such as WLAN access. Support for a non-3GPP access network (referred to as " standalone " Non-3GPP access) deployed outside the NG-RAN is described.

A 5G core network can support untrusted Non-3GPP access. The non-3GPP access network can be connected to the 5G core network through the non-3GPP interworking function (N3IWF). The N3IWF can interface the 5G core network CP and UP functions via the N2 and N3 interfaces, respectively.

The N2 and N3 reference points can be used to connect stand-alone Non-3GPP access to the 5G core network control plane and user plane functionality, respectively.

After UE attachment, a UE accessing a 5G core network through a standalone Non-3GPP access may support NAS signaling with a 5G core network control plane capability using an N1 reference point.

When the UE is connected through NG-RAN and standalone Non-3GPP access, there may be multiple N1 instances for the UE. That is, there may be one N1 instance for Non-3GPP access and NG-RAN.

If the selected N3IWF is located in the same PLMN as the 3GPP access, the UE concurrently connected to the same 5G core network of the PLMN via 3GPP access and Non-3GPP access may be serviced by a single AMF device.

When the UE is connected to the 3GPP access of the PLMN, the UE selects N3IWF and if the N3IWF is located in a PLMN different from the PLMN of the 3GPP access (e.g., another VPLMN or HPLMN) They can be serviced individually. The UE is registered with two separate AMFs. A PDU session over 3GPP access is serviced by a V-SMF that is different from the V-SMF servicing a PDU session over a Non-3GPP access.

The PLMN selection for 3GPP access does not depend on the N3IWF selection. If the UE is registered via Non-3GPP, the UE performs PLMN selection for 3GPP access independently of the PLMN to which the N3IWF belongs.

The UE can establish the N3IWF and IPSec tunnels to connect to the 5G core network through untrusted Non-3GPP access. The UE may be authenticated by the 5G core network during the IPSec tunnel establishment procedure and may be connected to the IP core 5G core network.

It must be able to maintain the UE signaling connection with the AMF device through the Non-3GPP access after all PDU sessions for the UE are released or handover to 3GPP access. N1 NAS signaling via standalone Non-3GPP access can be protected by the same security mechanism applied to N1 through 3GPP access.

<Registration Management>

Registration management is used to register or unregister user terminals / users in the network and is used to establish user contexts in the network.

The user terminal / user needs to register in the network in order to receive the service that requires registration. Once registered and applicable, the user terminal may 1) periodically (periodically update the registration) to make it reachable; Or 2) on move (mobility registration update); Or 3) update the registration on the network to update functionality or renegotiate protocol parameters:

The initial registration procedure involves the execution of network access control functions (i.e., user authentication and access authorization based on subscription profiles of the UDM). As a result of the registration procedure, the identifier of the serving AMF device for the UE in the UE registered access will be registered in the UDM.

The registration management procedure is applicable to both 3GPP access and non-3GPP access. 3GPP and non-3GPP registration states are independent of each other.

The following two registration management states reflecting the registration status of the user terminal in the selected PLMN are used in the user terminal and the AMF device:

I) RM-DEREGISTERED ii) RM-REGISTERED

Figure 1 illustrates a RM (Registration Management) state model of a user terminal according to an embodiment. Figure 2 also shows an RM state model of an AMF device according to one embodiment.

1. RM-DEREGISTERED state

In RM-DEREGISTERED state, the user terminal is not registered in the network. The user terminal is not reachable by the AMF device because the user terminal context in the AMF device does not have valid location or routing information for the user terminal. However, a portion of the user terminal context may still be stored in the user terminal and the AMF device for the sake of avoiding authentication procedures during all registration procedures.

In the RM-DEREGISTERED state, the user terminal:

I) If it is necessary to receive a service that requires registration, it tries to register with the selected PLMN using the initial registration procedure. Ii) Upon receipt of the registration rejection at the time of initial registration, the RM-DEREGISTERED state is maintained. Iii) Upon receipt of the registration approval, it enters the RM-REGISTERED state.

If the UE RM status of the AMF device is RM-DEREGISED, then the AMF device:

I) accept the initial registration of the user terminal by sending a registration grant to the user terminal, if applicable, and enter the RM-REGISTERED state for the UE; Or ii) rejecting the initial registration of the user terminal by sending a registration rejection to the user terminal, if applicable.

2. RM-REGISTERED state

In the RM-REGISTERED state, the user terminal is registered in the network. In the RM-REGISTERED state, the user terminal can receive services that need to register with the network.

In the RM-REGISTERED state, the user terminal:

I) perform the mobility registration update procedure if there is no current TAI of the serving cell in the list of TAIs received from the network by the user terminal in order to maintain registration and enable the AMF device to page the user terminal; Ii) Perform a periodic registration update procedure triggered by the expiration of the periodic update timer to notify the network that the user terminal is still active. Iii) update the function information by performing a registration information update procedure or renegotiate protocol parameters with the network. Iv) Performs the deregistration procedure and enters RM-DEREGISTERED state when the user terminal should no longer be registered in the PLMN. The user terminal may decide to unsubscribe from the network at any time. V) Enter RM-DEREGISTERED state when receiving registration decline message or deregistration message. The operation of the user terminal depends on the 'cause value' of the registration rejection or de-registration message.

If the UE RM state of the AMF device is RM-REGISTERED, the AMF device shall:

I) Perform the deregistration procedure and enter the RM-DEREGISTERED state when the user terminal should no longer be registered in the PLMN. The network may decide to de-register the user terminal at any time; Ii) implicit deregistration at any time after the expiration of the implicit de-registration timer. After implicit deregistration, the AMF device enters the RM-DEREGISTERED state for the user terminal. Iii) approve or reject a registration request or service request from the user terminal, where applicable;

3. Registration area management

Registration area management includes the function of assigning and reassigning the registration area to the UE. The registration area is managed for each access type (3GPP access or Non-3GPP access).

When the UE registers with the network via 3GPP access, the AMF may assign a set of tracking areas in the TAI List to the UE. When an AMF assigns to a UE a registration area (i.e., a set of tracking areas in a TAI list), the UE may consider various information (e.g., mobility patterns and allowed / non-allowed areas, etc.). An AMF with an entire PLMN as a serving region may alternatively allocate an entire PLMN (" all PLMNs ") as a registration region for the UE in the MICO mode.

The 5G system may support assigning a TAI list over a different 5G-RAT to a single TAI list.

When the UE registers with the network via a Non-3GPP access, the registration area for Non-3GPP access corresponds to a unique reserved TAI value (i.e., a value dedicated to Non-3GPP access) . Thus, there is a unique tracking area for Non-3GPP access to 5GC called N3GPP TAI.

When generating the TAI list, the AMF may include TAIs applicable to the access to which the TAI list is transmitted.

4. Support for UEs registered through 3GPP and Non-3GPP access

When the UE is serviced continuously or simultaneously by 3GPP access and Non-3GPP access (via N3IWF) of the same PLMN, there can be one RM context for the UE for each access to a given serving PLMN. The UDM can manage individual / independent UE registration procedures for each access.

When serviced by the same PLMN for 3GPP and non-3GPP access, the UE may be serviced by the same AMF except for mobility from the EPS while the UE has a PDU session associated with non-3GPP access.

The AMF may associate multiple access specific RM contexts for the UE with:

I) 5G-GUTI common to both 3GPP and non-3GPP access. This 5G-GUTI can represent values that are globally unique. Ii) Registration status by access type (3GPP / Non-3GPP) iii) Registration area by access type: Registration area for 3GPP access and different registration area for non-3GPP access. At this time, the registration areas for 3GPP access and non-3GPP access are independent. Iv) Periodic registration timer for 3GPP access. V) Non-3GPP Implicit Deregistration Timer.

The AMF can not provide the UE with a periodic registration timer via Non-3GPP access. As a result, the UE does not need to perform periodic registration update procedures for Non-3GPP access. Instead, during initial registration and re-registration, the UE may be provisioned by a network with a UE Non-3GPP deregistration timer that starts when the UE enters the Non-3GPP CM-IDLE state.

The 5G-GUTI may be allocated or reassigned via any 3GPP and non-3GPP access. The AMF assigns a single 5G-GUTI to be used through 3GPP and non-3GPP access of the same PLMN or equivalent PLMN (assuming control and user plane connectivity between registered PLMN and equivalent PLMN nodes) do. . The 5G-GUTI is allocated upon successful registration of the UE and is valid for both 3GPP and non-3GPP access to the same PLMN or equivalent PLMN for the UE. When performing any initial access via non-3GPP access or 3GPP access, the UE provides the 5G-GUTI received in an earlier successful registration through any access of the same PLMN or equivalent PLMN. This allows the AN to select the AMF that holds the UE context generated in the previous registration procedure and correlates the AMF with the UE context that exists.

If the UE performs registration through one access and wants to perform registration via another access in the same PLMN or an equivalent PLMN (e.g., 3GPP access and the selected N3IWF are located in the same PLMN) It may not start registration via another access until the registration procedure is completed.

If the UE is successfully registered with access (3GPP access or non-3GPP access respectively) and the UE registers with another access:

I) If the second access is in the same PLMN or equivalent PLMN (e.g., if the UE is registered through 3GPP access and chooses N3IWF located in the same PLMN), then the UE can not access the same PLMN or the first access The UE may use the provided 5G-GUTI for registration with the PLMN associated with the new access.

Ii) if the second access is located in a PLMN different from the registered PLMN of the first access (i.e., not a registered PLMN or a PLMN equivalent to the registered PLMN) (e.g., the UE is registered with 3GPP access and the 3GPP access , Or if the UE is registered via non-3GPP and registers with the 3GPP access in a PLMN different from the PLMN of N3IWF), then the UE receives the previously received 5G-GUTI from the equivalent PLMN The UE can use the 5G-GUTI to register with the PLMN associated with the new access. However, if the UE does not yet have a 5G-GUTI from the PLMN attempting to register or an equivalent PLMN, the SUCI may be used for a new registration.

When the UE 5G-GUTI allocated during the registration procedure through the 3GPP (for example, when the UE first registers through 3GPP access) is location-dependent, when the N3IWF function selected as the 3GPP access in the same PLMN is the same UE 5G-GUTI can be reused via non-3GPP access. If a UE 5G-GUTI is assigned during a registration procedure performed through non-3GPP access (e.g., the UE is initially registered through a non-3GPP access), the UE 5G-GUTI may not be location dependent, The UE 5G-GUTI may not be valid for the NAS procedure via 3GPP access and is assigned a new AMF during the registration procedure via 3GPP access.

When the UE is initially registered through 3GPP access, if the UE registers with the same PLMN through non-3GPP access, the UE may send the GUAMI obtained through the 3GPP access to the N3IWF. At this time, N3IWF can select the same AMF using the received GUAMI.

The deregistration request indicates whether it applies to 3GPP access, non-3GPP access, or both.

If the UE is registered with both 3GPP and non-3GPP access and is CM-IDLE with non-3GPP access, the UE or AMF initiates the deregistration procedure for 3GPP access and de-registers the UE on the non-3GPP . In this case, all PDU sessions associated with non-3GPP access may be released.

If the UE is registered with both 3GPP and Non-3GPP access and is CM-CONNECTED via CM-IDLE and non-3GPP access via 3GPP access, the UE initiates the deregistration procedure via non-3GPP access to initiate the 3GPP access Lt; RTI ID = 0.0 &gt; UE &lt; / RTI &gt; In this case, all PDU sessions associated with 3GPP access may be released.

<Connection Management>

Connection management is used to establish or release a signaling connection between the user terminal and the AMF device. Connection management includes the ability to establish and release a signaling connection between a user terminal and an AMF device via N1. This signaling connection is used to enable the exchange of NAS signaling between the user terminal and the core network. This includes both an AN signaling connection (3GPP access via N3GPP access or RRC connection via UE-N3IWF connection) between the user terminal and the AN and N2 connection to the user terminal between the AN and the AMF device.

Two CM states are used to reflect the NAS signaling connection of the AMF device and the user terminal:

Ⅰ) CM-IDLE ⅱ) CM-CONNECTED

The CM states for 3GPP access and Non-3GPP access are independent of each other. That is, when one is in the CM-CONNECTED state and the other is in the CM-IDLE state.

FIG. 3 illustrates a CM state transition at a user terminal according to an exemplary embodiment. 4 also shows the CM state transition in an AMF device according to one embodiment.

One. CM-IDLE state

The user terminal in the CM-IDLE state is connected to the AMF device and the established NAS

I do not have a signaling connection. The user terminal performs cell selection / cell reselection and performs PLMN selection.

The user terminal in the CM-IDLE state has no AN signaling connection, N2 connection and N3 connection.

When the user terminal is in the CM-IDLE state and the RM-REGISTERED state, the user terminal performs the following:

I) If the user terminal is not in the MICO mode, it performs a service request procedure to respond to paging. Ii) Perform a service request procedure when the user terminal has uplink signaling or user data to be transmitted. Certain conditions apply to the LADN.

Whenever an AN signaling connection is established between the user terminal and the AN (whenever the UE enters the RRC connection state via 3GPP access or establishes a UE-N3IWF connection via non-3GPP access), the user terminal enters the CM-CONNECTED state . The transmission of the initial NAS message (Registration Request, Service Request or Deregistration Request) initiates a transition from the CM-IDLE to the CM-CONNECTED state.

If the user terminal status of the AMF device is CM-IDLE and RM-REGISTERED, then the AMF device does the following:

I) If the UE is not prevented from responding, it performs a network triggered service request procedure when it has mobile-terminated data or signaling to be sent to the user terminal by sending a paging request to the user terminal.

Whenever an N2 connection is established for the user terminal between the AN and the AMF device, the AMF device enters the CM-CONNECTED state for the user terminal. Receipt of the initial N2 message (e.g., the user terminal message at the beginning of N2) initiates the transition of the AMF device from the CM-IDLE to the CM-CONNECTED state.

The user terminal and the AMF device can optimize the power efficiency and signaling efficiency of the user terminal when in the CM-IDLE state.

2. CM-CONNECTED state

The user terminal in the CM-CONNECTED state has NAS signaling connection with the AMF device via N1. The NAS signaling connection uses the RRC connection between the UE and the NG-RAN and the NGAP UE association between the AN and AMF devices for 3GPP access. The UE may be in a CM-CONNECTED state with a NGAP UE association not associated with any TNLA between the AN and the AMF device. Upon completion of the NAS signaling procedure, the AMF device may decide to release the NAS signaling connection with the user terminal.

In the CM-CONNECTED state, the UE performs the following:

I) enters the CM-IDLE state whenever the AN signaling connection is released (whenever an RRC idle state entry through 3GPP access or a release of the UE-N3IWF connection via non-3GPP access is detected by the user terminal) .

If the UE CM state of the AMF device is CM-CONNECTED, the AMF device performs the following:

I) Upon completion of the AN release procedure, each time a logical NGAP signaling connection and an N3 user plane connection to the UE are released, the UE enters the CM-IDLE state.

Until the UE is deregistered from the core network, the AMF device may maintain the UE CM state in the AMF device in the CM-CONNECTED state.

A UE in the CM-CONNECTED state may be in an RRC disabled state. When the UE is in the RRC disabled state the following applies:

I) UE reachability is managed by the RAN with assistance information from the core network. Ii) UE paging is managed by the RAN. Iii) The UE monitors paging with the CN's (5G S-TMSI) and RAN identifier.

3. CM-CONNECTED (CM-CONNECTED with RRC Inactive state)

The active state of RRC applies to NG-RAN. The AMF device based on the network configuration can provide assistance information to the NG-RAN to assist the NG-RAN in determining whether the UE can be transmitted in the RRC active state.

The "RRC Active Assistance Information" includes the following: i) UE specific DRX values. Ii) a registration area provided to the UE; Iii) a periodic registration update timer; iv) an indication that the UE is in MICO mode if the AMF device has enabled MICO mode for the UE.

The active assistance information, which is the RRC described above, is used for serving new (serving) NG-RAN nodes (i.e., during registration, service request, handover) to assist the NG RAN determining whether the UE can be transmitted in the RRC- Lt; RTI ID = 0.0 &gt; N2 &lt; / RTI &gt; The RRC inactive state is part of the RRC state machine, and it is up to the RAN to determine the conditions for entry into the RRC active state. When one of the parameters included in the active assistance information, which is the RRC, is changed as a result of the NAS procedure, the AMF device updates the active assistance information, which is the RRC, to the NG-RAN node.

When the UE is in the CM-CONNECTED state, if the AMF device provides active assistance information that is an RRC, the RAN node may decide to move the UE to the CM-CONNECTED active state, which is the RRC.

The state of the N2 and N3 reference points is not changed by the UE entering CM-CONNECTED in the RRC disabled state. A UE in the RRC disabled state knows the RAN Notification area.

Unless notified to the 5GC network through the N2 Notification procedure, the 5GC network will not be aware of UE transitions between CM-CONNECTED in the RRC-connected state and CM-CONNECTED in the RRC-active state.

Upon switching to CM-CONNECTED in the RRC active state, the UE applies the periodic RAN notification area update and the timer in the UE and RAN can be restarted.

When assigning a periodic RAN notification area update timer, the NG-RAN can consider the periodic registration update timer value indicated in the active assistance information, which is the RRC.

If the periodic RAN notification area update timer expires in the RAN, the RAN starts the RRC release timer. When the RRC release timer expires, the RAN initiates the UE context release in the AN procedure.

If the UE is in the active CM connection state, which is the RRC, the UE may perform the PLMN selection procedure for CM-IDLE.

If the UE is CM-CONNECTED in the RRC active state, the UE may resume the RRC connection for the following reasons: i) waiting for uplink data; Ii) Mobile initiated NAS signaling procedure; Iii) response to RAN paging; Iv) Notify the network that it has left the RAN notification area. V) Periodic RAN update timer expires.

When the UE resumes the connection at the other NG-RAN node in the same PLMN, the UE AS context is retrieved from the existing NG-RAN node and the related procedure is triggered towards the CN.

If the RAN paging procedure does not successfully establish a connection with the UE, the procedure is handled by the network as follows: i) If the NG-RAN has a pending NAS PDU for transmission, To the CM-IDLE state and initiate the NAS signal connection release procedure to direct the NAS non-delivery to the AMF device. Ii) If the NG RAN transmits pending user plane data, the NG-RAN node either maintains the N2 connection or initiates the NAS signal connection release procedure based on the local configuration of the NG-RAN.

If the UE in the CM-CONNECTED in the RRC inactive state performs cell selection with GERAN / UTRAN / EPS, the IDLE mode procedure is followed.

In addition, a UE in the CM-CONNECTED state having the RRC active state enters the CM-IDLE mode and follows the related NAS procedure: i) if the RRC restart procedure fails, ii) Upon receipt, iii) the periodic RAN notification area update timer expires and the UE can not successfully resume the RRC connection.

If the UE is in the CM-CONNECTED state with the RRC active state, and the RAN receives the location report control message in the AMF device with a report type indicating a single stand-alone report, the RAN performs RAN paging before reporting the location to the AMF do.

When the UE is in the CM-CONNECTED state with the RRC active state, and the RAN receives a location report control message indicating a persistent report from the AMF each time the UE changes the cell, the RAN is informed of the last known And transmits the location report message to the AMF including the location.

<NAS signaling connection management>

The management of NAS signal connections includes the ability to establish and release NAS signal connections.

The NAS signaling connection establishment function is provided by the UE and the AMF device to establish a NAS signaling connection for the UE in the CM-IDLE state. The AMF provides a list of recommended cell / TA / NG-RAN node identifiers for paging if the NG-RAN has provided relevant information in the initial UE context release procedure within the AN.

When the UE in the CM-IDLE state needs to transmit a NAS message, the UE starts a service request or registration procedure to establish a signal connection to the AMF device. Based on the UE preferences, the UE subscription, the UE mobility pattern and the network configuration, the AMF device can maintain the NAS signal connection until the UE deregisters from the network.

The procedure for releasing the NAS signaling connection is initiated by the AN node (5G (R) AN node or non-3GPP access node) or the AMF device. The NG-RAN node may include a list of recommended cell / TA / NG-RAN node identifiers for paging during UE context release procedures within the AN. The AMF device stores relevant information when provided by the NG-RAN.

The UE assumes that the NAS signaling connection is released when it detects that the AN signaling connection has been released. The AMF device assumes that the NAS signaling connection is released when it detects that the N2 context has been released.

<UE mobility limitation>

The mobility restriction limits the mobility handling or service access of the UE in the 5G system. The mobility restriction function is provided by the UE, the radio access network and the core network. The mobility restriction applies only to 3GPP access and not to non-3GPP access.

When in the RRC Inactive state, the mobility constraints for the CM-IDLE and CM-CONNECTED states are performed by the UE based on information received from the core network. When in the RRC-Connected state, mobility restrictions on the CM-CONNECTED state are performed by the radio access network and the core network.

In the CM-CONNECTED state, the core network provides mobility restriction to the radio access network within the Handover Restriction List.

The mobility restriction consists of: i) RAT restrictions, ii) prohibited areas, iii) service area restrictions, and iv) core network type restrictions, as follows:

I) RAT limitation:

Defines a 3GPP radio access technology in which the UE is not allowed to access the PLMN. In a limited RAT, the UE is based on a subscription that is not authorized to initiate any communications to the PLMN. In the CM-CONNECTED state, when the radio access network determines the target RAT and the target PLMN during the handover procedure, it can be considered according to the PLMN RAT restriction.

Ⅱ) Forbidden Area:

In the forbidden area of a given RAT, the UE is based on a subscription that is not authorized to initiate any communication with the network for the PLMN. The UE behavior in relation to cell selection, RAT selection and PLMN selection depends on the network response informing the UE of the forbidden area.

Iii) Service area restrictions:

1) Allowed area: In the allowed area of a given RAT, the UE initiates communication with the network as allowed by the subscription. . Non-Allowed Area: In a non-allowed area of a given RAT, the UE may be limited in service area based on the subscription. The UE and the network are not allowed to initiate a service request or SM signaling to obtain a user service (in both the CM-IDLE and CM-CONNECTED states). The RRC procedure while the UE is in the CM-CONNECTED state with the RRC disabled state is unchanged compared to when the UE is in the allowed area. The RM procedure is unchanged compared to when the UE is in the allowed area. A UE in the unauthorized area can respond to core network paging with service request and RAN paging.

Iv) Core network type limitation:

Defines whether the UE is allowed to connect to the 5GC for the PLMN.

For a given UE, the core network determines mobility constraints based on UE subscription information, UE location and local policy. The mobility restriction may be changed, for example, due to the subscription, location change and local policy of the UE. Optionally, the service area limitation or unauthorized area may be further fine-tuned by the PCF based on the UE location, PEI and network policy. The service area limitation may be updated during the registration procedure or the UE configuration update procedure.

When the network sends a service area restriction to the UE, the network transmits only one of the allowed or unallowed areas, but does not transmit both at the same time. If the UE has received the allowed region from the network, any TA that is not part of the allowed region is deemed unacceptable by the UE. When a UE receives an unauthorized region from the network, any TA that is not part of the unauthorized region is considered to be allowed by the UE. If the UE does not receive any service area restrictions, any TA in the PLMN is considered to be allowed.

If the UE has overlapping areas between RAT limits, prohibited areas, service area limits or any combination thereof, the UE may proceed with the following priorities:

I) The evaluation of the RAT restriction takes precedence over the evaluation of any other mobility limitation; And ii) the evaluation of the prohibited area takes precedence over the evaluation of the service area limitation. Iii) Evaluation of unauthorized areas shall take precedence over evaluation of permitted areas.

The UE may override the RAT restriction, the forbidden area, and the unacceptable area limit whenever the network is accessed for regulatory prioritized services such as emergency services and MPS. The network may also override unauthorized zone limits and RAT limits for regulated services such as emergency services and MPS.

<Mobility pattern>

The mobility pattern is a concept that can be used by the AMF to characterize and optimize UE mobility. The AMF determines and updates the mobility pattern of the UE based on the UE's subscription, UE mobility statistics, network local policy and UE assisted information, or any combination thereof. The statistics of UE mobility may be historical or expected UE moving trajectory.

The UE mobility pattern may be used by the AMF to optimize mobility support provided to the UE (e.g., Registration area allocation).

&Lt; UE reachability in CM-IDLE state in 3GPP access >

The reachability management can serve to detect if the UE is reachable and to provide a UE location (i.e., an access node) to reach the UE in the network. This is done by paging UE and UE location tracking. UE location tracking includes both UE registration area tracking (i.e., UE registration area update) and UE reachability tracking (i.e., UE periodic registration area update). These functions can be located in 5GC (for CM-IDLE state) or NG-RAN (for CM-CONNECTED state).

The UE and the AMF negotiate UE reachability characteristics for the CM-IDLE state during the registration and registration update procedure.

Two UE reachability categories are negotiated between the UE and the AMF for the CM-IDLE state:

I) UE reachability allows mobile termination data while the UE is in the CM-IDLE state. The UE location is known by the network as a subdivision of the tracking area list. ② Paging procedures can be applied to these categories. (3) Mobile originating and mobile terminated data can be applied to these categories for both CM-CONNECTED and CM-IDLE states.

Mobile Initiated Connection Only (MICO) mode: ① Mobile originated data can be applied to this category for both CM-CONNECTED and CM-IDLE states. (2) Mobile terminated data can be supported only when the UE is in the CM-CONNECTED state.

Each time the UE in the RM-REGISTERED state enters the CM-IDLE state, it starts a periodic registration timer according to the periodic registration timer value received from the AMF during the registration procedure.

The AMF allocates a periodic registration timer value to the UE based on local policy, subscription information and information provided by the UE. After the periodic registration timer expires, the UE may perform periodic registration. If the UE is out of network coverage when the periodic registration timer expires, the UE may perform a registration update upon return to coverage.

The AMF executes a mobile reachable timer for the UE. The timer starts with a value longer than the UE's periodic registration timer whenever the CM state for the UE in the RM-REGISTERED state changes to CM-IDLE. When the AMF receives an elapsed time from the RAN when the RAN initiates a UE context release indicating that the UE is unreachable, the AMF is based on the elapsed time received from the RAN and the normal (nomal) mobile reachable timer value To deduce the mobile reachable timer value. The AMF can stop the mobile reachable timer if the UE CM state of the AMF moves to the CM-CONNECTED state. When the mobile reachable timer expires, the AMF determines that the UE is not reachable.

However, since the AMF does not know how long the UE can not reach, the AMF may not immediately de-register the UE. Instead, after expiration of the mobile reachable timer, the AMF can clear the PPF flag and start an implicit de-registration timer with a relatively large value. If the AMF moves the UE CM state of the AMF to the CM-CONNECTED state, the AMF may stop the implicit de-registration timer and set the PPF flag.

If the PPF is not set, the AMF does not page the UE and may reject the DL signaling or any request to forward the data to the UE.

If the implicit de-registration timer expires before the UE connects to the network, the AMF implicitly de-registers the UE.

As part of deregistration for a particular access (3GPP or non-3GPP access), the AMF may request the associated SMF of the UE to release the PDU session established for the particular access.

UE reachability in CM-IDLE state in 3GPP access: UE reachability allows mobile terminated data while UE is in CM-IDLE state < RTI ID = 0.0 >

If the UE does not apply the MICO mode, the AMF can consider that the UE in the RM-REGISTERED state is reachable by CN fading if the UE CM state of the AMF is in the CM-IDLE state.

<UE reachability in CM-IDLE state in 3GPP access: Mobile Initiated Connection Only (MICO) mode>

The UE may indicate a preference for the MICO mode during initial registration or registration update. The AMF device determines whether the MICO mode is allowed for the UE based on the local configuration, the communication pattern, UE preference, UE subscription information and network policy, or any combination thereof, if available, Display.

The UE and the core network restart or terminate the MICO mode at the next registration signaling. If the registration procedure does not explicitly indicate the MICO mode and the registration procedure is successful, both the UE and the AMF device do not use the MICO mode. That is, the UE operates as a normal UE, and the network treats the UE as a normal UE.

The AMF device assigns a registration area to the UE during the registration procedure. When the AMF device indicates the MICO mode to the UE, the registration area is not limited by the paging area size. If the AMF service area is the entire PLMN based on the local policy and subscription information, it may decide to provide the UE with the " all PLMN " registration area. In this case, re-registration for the same PLMN due to mobility does not apply.

If mobility constraints are applied to the UE in the MICO mode, the AMF device may allocate the allowed / unallowed areas to the UE.

When the AMF indicates the MICO mode to the UE, the AMF assumes that the UE can not always reach the UE while the UE CM state is CM-IDLE. The AMF rejects any request for downlink data transfer to the UE in the MICO mode and the UE CM state in the AMF is CM-IDLE for the appropriate cause. AMF also defers downlink transmissions over the NAS for SMS, location services, and so on. A UE in MICO mode can only reach mobile termination data or signaling when the UE is CM-CONNECTED.

The UE in MICO mode does not need to listen for paging during CM-IDLE. The UE in MICO mode may suspend any access layer procedure in CM-IDLE until the UE starts switching from CM-IDLE to CM-CONNECTED due to one of the following triggers: i) Lt; / RTI &gt; Ii) The periodic registration timer expires. Iii) MO data is pending. Iv) Hold the MO signal (eg start SM procedure).

If a registration area other than the " all PLMN " registration area is assigned to the UE in the MICO mode, the UE determines whether it is in the registration area when it has MO data or MO signaling.

&Lt; UE reachability in CM-CONNECTED state in 3GPP access >

For UEs in the CM-CONNECTED state: i) The AMF knows the UE location in the serving (R) AN node granularity. Ii) If the UE can not be reached from the (R) AN point of view, the NG-RAN informs the AMF.

UE RAN reachability management is used by RANs for UEs in active state being RRCs. The location of the UE in the RRC active state is known by the RAN according to the RAN notification area granularity. The UE in the RRC inactive state is paged in the cells of the RAN notification area allocated to the UEs. The RAN notification area may be a subset of cells configured in the registration area of the UE or all cells configured in the registration area of the UE. An active RRC UE performs a paging area update when entering a cell that is not part of the RAN notification area allocated to the UE.

When switching to the RRC inactive state, the RAN configures the UE with a periodic RAN notification area update timer value, and the timer is restarted at the UE and restarted at the RAN with the initial timer value. The UE in the active state, which is the RRC, performs periodic RAN notification area update after the periodic RAN notification area update timer expires.

To help manage UE reachability in the AMF, upon expiration of the RAN's periodic RAN notification area update timer, the RAN starts the RRC release timer. When the RRC release timer expires, the RAN can initialize the UE context release in the AN procedure.

&Lt; Process of paging strategy in 3GPP access >

Based on the operator configuration, 5GS supports AMF and NG-RAN to apply different paging strategies for different types of traffic.

In the case of a UE in the CM-IDLE state, the AMF performs the paging and performs a paging strategy based on, for example, the local configuration, the reason the NF triggered the paging, and the information available in the request that triggered the paging .

For UEs that are CM-CONNECTED with RRC disabled, the NG-RAN performs paging and determines the paging strategy based on information received from, for example, the local configuration, AMF and SMF.

For a network triggered service request from the SMF, the SMF determines the 5QI and ARP based on the notification of the downlink data or the downlink data received from the UPF. The SMF contains the 5QI and ARP corresponding to the downlink PDU received in the request sent to the AMF. If the UE is in CM IDLE, AMF can use 5QI and ARP to derive other paging strategies.

&Lt; Differentiation of Paging Policy in 3GPP Access >

Paging policy differentiation is an optional feature that allows the AMF to apply different paging strategies to different traffic or service types provided within the same PDU session based on the operator configuration. This feature can only be applied to IP type PDU sessions.

When 5GS supports the Paging Policy Differentiation (PPD) feature, the DSCP value (TOS of TC / IPv4 in IPv6) can be set by the application to indicate to the 5GS that the paging policy should be applied to a specific IP packet.

Operators can configure the SMF in such a way that the paging policy differentiation feature applies only to specific HPLMNs, DNNs, and 5QIs. In the case of HR roaming, this configuration can be performed in the SMF of the VPLMN.

Network-Triggered Service Request and UPF Buffering In the case of a downlink data packet, the UPF contains the DSCP in the TOS (IPv4) / TC (IPv6) value from the IP header of the downlink data packet, and in the data notification message sent to the SMF And an indication of the corresponding QoS flow.

When the PPD is applied, the SMF determines the PPI (Paging Policy Indicator) based on the information received from the UPF. Network triggered service request and SMF buffering For the downlink data packet, when the PPD is applied, the SMF determines the PPI based on the DSCP in the TOS (IPv4) / TC (IPv6) value from the IP header of the received downlink data packet And determine the indication of the corresponding QoS flow. The SMF includes the PPI, ARP and 5QI of the N11 message sent to the AMF. If the UE is in CM IDLE, the AMF derives the paging strategy using the information and sends the paging message to the NG-RAN via N2. The paging message sent to the NG-RAN may include a PPI.

The SMF configures the UPF to include other QoS flow traffic with different paging differentiation requirements and assigns N2 to the Paging Policy Indicator (PPI) for the QoS flow (QFI) of the PDU session for the NG-RAN. Lt; / RTI &gt;

&Lt; Paging Priority in 3GPP Access >

The paging priority is a feature that allows the AMF to include an indication in the paging message sent to the NG-RAN so that the UE is paged in priority order. Whether to include the paging priority in the paging message is determined based on the ARP value of the message received from the SMF for the IP packet waiting for the AMF to be delivered in the UPF. If the ARP value is associated with a selective priority service (e. G., MPS, MCS), the AMF includes a paging priority in the paging message. When the NG-RAN receives a paging message having a paging priority, it processes a page having priority.

The AMF receives another message from the SMF with the ARP associated with the selection priority service (e.g., MPS, MCS) while waiting for the UE to respond to the page sent without priority, and the AMF sends another paging message To the (R) AN.

<Registration Management in Non-3GPP Access>

The UE enters the RM-DEREGISTERED state and the AMF enters the RM-DEREGISTERED state for the UE with non-3GPP access as follows:

I) at the UE and AMF after performing an explicit deregistration procedure; Ii) In the AMF, after the network non-3GPP implicit de-registration timer expires. Iii) At the UE, after the UE non-3GPP deregistration timer expires.

Whenever a UE registered through non-3GPP access enters the CM-IDLE state for non-3GPP access, it starts the UE non-3GPP de-registration timer according to the value received from the AMF during the registration procedure.

Through non-3GPP access, the AMF implements a network non-3GPP implicit de-registration timer. The network non-3GPP implicit de-registration timer is set to a value longer than the non-3GPP de-registration timer of the UE whenever the CM state for the UE registered through non-3GPP access is changed to CM-IDLE for non-3GPP access .

For a UE registered via non-3GPP access, the change of the attachment point (e.g., a change of the WLAN AP) does not induce the UE to perform the registration update procedure.

The UE should not provide 3GPP-specific parameters (e.g., indicating a preference for the MICO mode) during registration through non-3GPP access.

<Connection Management in Non-3GPP Access>

A UE successfully establishing an NWu connection through an untrusted Non-3GPP access transitions to the CM-CONNECTED state for untrusted Non-3GPP access.

For untrusted non-3GPP access to 5GC, the NWu signal is released as a result of an explicit unregistration procedure or AN release procedure. In addition, N3IWF can explicitly release the NWu signal connection due to NWu connection failure. The release of the NWu signaling connection between the UE and the N3IWF can be interpreted as follows:

I) Release the N2 connection based on N3IWF.

Ii) if the NWu connection release does not occur as part of the deregistration procedure for non-3GPP access where the UE enters the RM-DEREGISTERED state, as a criterion that the UE transitions to CM-IDLE, The UE registered with the UE remains in the RM-REGISTERED state. When the UE in RM-REGISTERED transitions to CM-IDLE, the UE non-3GPP deregistration timer starts running in the UE. The UE non-3GPP deregistration timer stops when the UE moves into the CM-CONNECTED state or the RM-DEREGISTERED state.

For untrusted Non-3GPP access, when the AMF releases the N2 interface, the N3IWF releases all resources associated with the UE, including the NWu connection with the UE. The release of the N2 connection by the AMF sets the CM state for the UE in the AMF to CM-IDLE.

The UE can not be paged with untrusted Non-3GPP access.

Whether the UE registers simultaneously through 3GPP access and non-3GPP access and the UE moves all PDU sessions to one of the accesses, whether the UE initiates the deregistration procedure in an access without a PDU session, .

The release of a PDU session via non-3GPP access does not imply a release of the N2 connection.

If the UE has a PDU session routed through a non-3GPP access and the UE state becomes CM-IDLE for non-3GPP access, then this PDU session may be initiated when the UE moves PDU sessions via 3GPP access based on UE policies And is not released. The core network maintains the PDU session but disables the N3 user plane connection for such PDU session.

<UE reachability of CM-IDLE in non-3GPP access>

The UE can not be paged through untrusted non-3GPP access.

If the UE state at the AMF is CM-IDLE and RM-REGISTER for non-3GPP access, there may be a last routed PDU session over non-3GPP access without user plane resources. If the AMF receives a data notification with a non-3GPP access type indication from the SMF for a PDU session corresponding to a UE that is CM-IDLE for non-3GPP access and the UE is registered via 3GPP access in the same PLMN, The service request may be performed through 3GPP access regardless of whether the UE is CM-IDLE or CM-CONNECTED via 3GPP access. In this case, the AMF provides an indication that the procedure is associated with downlink data retention for non-3GPP access. If the UE is in CM-IDLE via 3GPP access, the AMF does not include the PDU session ID of the specific PDU session whose access type is set to non-3GPP access.

<UE reachability of CM-CONNECTED in non-3GPP access>

For UEs in the CM-CONNECTED state: i) The AMF knows the N3IWF node granular UE location. Ii) The N3IWF releases the N2 connection when the UE becomes unreachable (ie, when NWu is released).

<Session Management>

The 5G core network supports the PDU connectivity service. The PDU connectivity service provides for the exchange of PDUs between the user terminal and the data network. The PDU connectivity service is supported through PDU sessions established in response to a request from the user terminal.

The subscription information includes a plurality of data network names and a default data network name. If a valid data network name is not provided in the PDU session establishment request transmitted to the 5G core network, the user terminal is assigned to the default data network name

Each PDU session supports one PDU session type. The PDU session supports the exchange of a single type of PDU session requested by the user terminal in the establishment of the PDU session.

The PDU session is established using the NAS SM signaling exchanged between the UE and the SMF device via N1, the PDU session being established upon request of the user terminal, modified according to the request of the user terminal and the 5G core network, , And may be released at the request of the user terminal and the 5G core network. At the request of the application server, the 5G core network can trigger a specific application of the UE. Upon receipt of the trigger message, the user terminal forwards to the identified application. An application identified at the user terminal may establish a PDU session for a particular DNN.

The SMF device may support PDU sessions for LADNs where access to the data network is available only in a particular LADN service area.

The SMF device checks whether the user terminal request is compliant with the user subscription. To do this, it retrieves and requests update notifications for SMF device level subscription data from the UDM. Such data can be represented for each DNN and, where applicable, for each S-NSSAI:

I) Allowed PDU session type and default PDU session type. Ii) Allowed SSC mode and default SSC mode. Iii) QoS information: Subscribed Session-AMBR, Default 5QI, and Default ARP. Iv) Fixed IP address / prefix.

A user terminal registered through a plurality of accesses selects access to establish a PDU session. The HPLMN may send a policy to the user terminal to guide the selection of access to establish a PDU session to the user terminal.

The user terminal may request to move the PDU session between the 3GPP access and the non-3GPP access. The decision to move the PDU session between 3GPP access and non-3GPP access is done on a per-PDU session basis. That is, the user terminal may have some PDU sessions using 3GPP access at a given time, and other PDU sessions may use non-3GPP access.

In a PDU session establishment request sent over the network, the user terminal provides a PDU session identifier. The PDU session ID is unique to each user terminal and is an identifier used to uniquely identify one of the user terminal's PDU sessions. The PDU session ID is stored in the UDM to support handover between 3GPP and non-3GPP access when different PLMNs are used for both accesses. The UE may also provide:

I) PDU session type. Ii) S-NSSAI. Iii) DNN (Data Network Name). Iv) SSC mode.

The user terminal may establish a plurality of PDU sessions to the same data network or another data network at the same time through the 3GPP and non-3GPP access networks.

The user terminal is served by another UPF device that establishes multiple PDU sessions for the same data network and terminates N6.

A user terminal having a plurality of established PDU sessions may be served by another SMF device.

The SMF device can be registered and unregistered in PDU session granularity of the UDM.

The user plane path of different PDU sessions (for the same or different data network names) belonging to the same user terminal may be completely disjoint between the UPF device and the AN that interfaces with the data network.

<Session management: Interaction between AMF and SMF devices>

The AMF and SMF devices are separate network functions.

The interaction with N1 related SMF devices is as follows:

I) A single N1 termination point is located in the AMF device. The AMF device forwards the SM related NAS information to the SMF device based on the PDU session ID of the NAS message. In addition, an SM NAS exchange (e.g., SM NAS message responses) for N1 NAS signaling received by the AMF device via an access (e.g., 3GPP access or non-3GPP access) is transmitted over the same access . Ii) The serving PLMN may send a subsequent SM NAS exchange (e.g., an SM NAS message response) to the N1 NAS signaling received by the AMF device via an access (e.g., 3GPP access or Non-3GPP access) To be transmitted through the same access. Iii) The SMF device handles the session management portion of the NAS signaling exchanged with the user terminal. Iv) The user terminal initializes PDU session establishment in the RM-REGISTERED state. V) If an SMF device is selected to serve a particular PDU session, the AMF device ensures that all NAS signaling associated with the PDU session is handled by the same SMF device instance. Vi) Upon establishing a successful PDU session, the AMF device and the SMF device store the associated access type of the PDU session.

The N11 related interactions with the SMF device are as follows:

I) The AMF device includes user terminal location information for the area of interest indicated by the SMF device to report the reachability of the user terminal based on the subscription of the SMF device, including: Ii) The SMF device indicates to the AMF device when a PDU session is released. Iii) Upon establishing a successful PDU session, the AMF device stores the identifier of the serving SMF device of the user terminal, and the SMF device stores the identifier of the serving AMF device of the UE including the AMF device set. When attempting to reach an AMF device serving a user terminal, the SMF device needs to apply the behavior described for " other CP NFs ".

N2 Interactions with related SMF devices are as follows:

I) Some N2 signaling (e.g., handover related signaling) may require actions of the AMF device and the SMF device. In this case, the AMF device guarantees coordination between the AMF device and the SMF device. The AMF device may forward the SM N2 signaling to the corresponding SMF device based on the PDU session ID in N2 signaling. Ii) The SMF device provides the PDU session type with the PDU session ID to the NG-RAN so that the NG-RAN can apply a header compression mechanism suitable for packets of other PDU types.

N3 Interactions with related SMF devices are as follows:

I) Selective activation and deactivation of the UP connection of an existing PDU session is defined.

N4 Interactions with related SMF devices are as follows:

I) If the UPF device recognizes that some DL data has arrived for the user terminal without downlink N3 tunnel information, the SMF device interacts with the AMF device to initiate a network triggered service request procedure. In this case, if the SMF device recognizes that the UE can not reach or that the UE can only reach a prioritized service and that the PDU session is not for regulated services, Notify the AMF device of the notification.

The AMF device can select the SMF device according to the procedure. To do this, subscription data can be obtained from the UDM. It may also retrieve the subscribed UE-AMBR from the UDM and send it to the (R) AN.

AMF device to support LADN-SMF device interaction is defined.

In order to support billing data collection and meet regulatory requirements related to the establishment, modification and release of IMS voice calls (to provide NPLI - network provided location information) the following applies:

I) When PEI can be used in AMF device when PDU session is established, AMF device provides PEI of user terminal to SMF device. When transmitting an UL NAS or N2 signaling to a peer NF (eg SMF device or SMSF) during UP connection activation of the PDU session, the AMF device transmits the UL location information received from the 5G-AN and the UL NAS or N2 (3GPP or Non-3GPP) as well as the corresponding UE time zone that received the signaling.

The user location information, access type and UE time zone may be further provided by an SMF device or PCF. PCF can obtain information from SMF devices to provide NPLI to applications (eg, IMS).

The user location information may correspond to:

I) For NG-RAN: Cell-Id. Ii) For N3IWF: User terminal local IP address (used to reach N3IWF) and optionally UDP or TCP source port number (if NAT is detected).

<Session Management: Support for local area data network (LADN)>

Access to the DN through the PDU session to the LADN can only be used in a specific LADN service area. The LADN service area is a TA (Tracking Areas) set. The 5GC supports the UE to recognize the availability of the LADN based on the UE location.

In the case of LADN, the AMF provides LADN information on the LADN availability to the UE, and the AMF keeps track of whether the UE is located in the LADN service area (i.e., the availability area of the LADN) and notifies the SMF.

LADN information is configured for each DN in the AMF, i. E., For different UEs accessing the same LADN, and the configured LADN service area is the same regardless of other elements (e. G.

The LADN information provided to the UE by the AMF consists of the LADN DNN and LADN service area information availability for the UE. The LADN service area information provided to the UE during the registration procedure includes a set of tracking areas (TA) belonging to the UE's current registration area (i. E., The intersection area of the LADN service area and the current registration area). The AMF may not create a registration area according to the availability of the LADN.

When the UE performs a successful re-registration procedure, the AMF sends to the UE the policies provided by the PCF based on the LADN information, the UE location, the local configuration information about the UE subscription information received from the UDM regarding the subscribed LADN DNNs, The LADN information for the LADN available to the UE from the RA in the registration response acknowledgment message can be provided.

If the LADN information for the UE changes at 5GC, the AMF can update the LADN information to the UE through the UE Configuration Update procedure.

Based on the LADN availability information in the UE, the UE may request establishment of a PDU session for the LADN available when the UE is located in the LADN service area. When the UE is outside the LADN service area, the UE can not request a PDU session for the LADN and the SMF may reject the request. When the UE is located outside the LADN service area, the UE does not trigger a service request for establishing the user plane for the LADN PDU session and the SMF rejects the establishment of the user plane for the LADN PDU session.

The SMF can subscribe to the " UE Location Notification ". Based on the UE location information received from the AMF, the SMF can determine whether: i) a network-triggered service request for a LADN PDU session whose user plane connection has been deactivated should be triggered; ii) whether a PDU session Or iii) deactivates the user plane connection to the PDU session and maintains the PDU session. The network may release the PDU session at any time according to the network policy. The SMF may also request that the UPF discard the downlink data for the PDU session (discard) and not send a data notification message to the SMF.

This decision can be influenced by local policy.

If the SMF determines that the UE is outside the coverage area of the LADN based on the latest UE location received after the UE has been paged and the UE has triggered the service request procedure, the SMF will reject the establishment of the user plane for the LADN PDU session .

When leaving the LADN service area, the UE does not need to release a LADN PDU session unless the UE receives an explicit PDU session release request from the network.

If the SMF is aware that the UE is outside the available area of the LADN, the SMF can not trigger a user plane re-establishment for the PDU session corresponding to the LADN.

If the AMF detects that the UE has returned to the LADN service area, the AMF notifies the SMF based on the SMF subscription for the area of interest corresponding to the LADN. If there is DL data with an SMF or UPF pending, the SMF can perform a network trigger service request to establish the user plane for the PDU session. Otherwise, the SMF may resume the UPF to retransmit the DL data notification to the SMF for DL data.

In these releases, LADN applies only to 3GPP access.

<Session management: Selective activation and deactivation of UP connection of existing PDU session>

This applies when the UE establishes multiple PDU sessions. Activation of the UP connection of an existing PDU session may cause activation of the UE-CN user plane connection (i. E., Data radio bearer and N3 tunnel).

For a UE in the CM-IDLE state in 3GPP access, the UE or network triggered service request procedure may support independent activation of the UP connection of an existing PDU session. For UEs in the CM-IDLE state in non-3GPP access, the UE triggered service request procedure may allow re-activation of the UP connection of existing PDU sessions and support independent activation of the UP connection of an existing PDU session .

The UE in the CM-CONNECTED state may invoke the service request procedure to request independent activation of the UP connection of existing PDU sessions.

The network triggered reactivation for the UP connection of an existing PDU session is handled as follows:

I) If the UE CM status in the AMF is already CM-CONNECTED on the access (3GPP, non-3GPP) associated with the PDU session in the SMF, the network can reactivate the UP connection of the PDU session using the network- have.

Otherwise:

Ii) if the UE is registered with both 3GPP and non-3GPP access and the UE CM status in the AMF is CM-IDLE in non-3GPP access, then the UE can initiate 3GPP access in the SMF or 3GPP access (1) if the UE CM status in the AMF is CM-IDLE in 3GPP access, then the paging message may include the access type associated with the PDU session in the SMF. Upon receiving a paging message containing an access type, the UE includes a PDU session list associated with the received access type and responds to the 5GC through 3GPP access using a NAS service request message through which the UP connection can be reactivated via 3GPP access . (I. E., The list does not include PDU sessions whose UP connection can not be reactivated in 3GPP according to UE policy). If the UE is in the list of PDU sessions provided in the NAS service request, the 5GC may reactivate the PDU session UP connection via 3GPP access. (2) If the UE CM status of the AMF is CM-CONNECTED in 3GPP access, the notification message may include the PDU session ID. Upon receiving the notification message, the UE may respond to the 5GC through the 3GPP access using a NAS service request message including an indication of whether the PDU session UP connection can be reactivated via 3GPP.

Iii) If the UE is registered in both 3GPP and non-3GPP accesses serviced by the same AMF and the UE CM status in the AMF is CM-IDLE in 3GPP access and CM-CONNECTED in non-3GPP access, Through 3GPP, the SMF can be informed of the PDU session associated with the 3GPP access (i.e., last routed). The notification message includes the PDU session ID. Upon receiving the notification message, when 3GPP access is enabled, the UE can respond to the 5GC through the 3GPP access using the NAS service request message.

Deactivation of the UP connection of an existing PDU session causes the corresponding data radio bearer and N3 tunnel to be deactivated. The UP connection of other PDU sessions may be deactivated independently when the UE is in the CM-CONNECTED state in 3GPP access or non-3GPP access.

<Session Management: Session and Service Continuity>

Supporting session and service continuity in the 5G system architecture can ensure addresses of various continuity requirements of different applications and services for the user terminal. 5G systems support different session and service continuity modes (SSCs). The SSC mode associated with the PDU session is not changed during the lifetime of the PDU session.

I) In SSC mode 1, the network preserves the continuity service to be provided to the user terminal. In an IPv4, IPv6 type PDU session, the IP address is preserved. Ii) In SSC mode 2, the network may release the continuity service to be sent to the user terminal and release the PDU session corresponding to the continuity service. In the IPv4, IPv6 type, the network may release the IP addresses assigned to the user terminal. In SSC mode 3, a change in the user plane is visible to the user terminal. On the other hand, the network ensures that the user terminal does not incur any loss of connectivity. The connection through the new PDU session anchor point is established before the previous connection is disconnected for better service continuity. IP address is not preserved in SSC mode 3 when the PDU session anchor is changed for IPv4, IPv6 type.

The process of adding or removing additional PDU session anchors in a PDU session for local access to the data network is independent of the SSC mode of the PDU session.

<Service & Session Continuity mode>

(1) SSC mode 1

For a PDU session in SSC mode 1, a UPF device acting as a PDU session anchor in establishing a PDU session maintains the user terminal regardless of the access technology (ex / access type, cells) for successful access to the network do.

For IPv4 and IPv6 type PDU sessions, IP continuity is supported regardless of user terminal mobility events.

If the IPv6 multi-home or uplink delimiter is applied to a PDU session in SSC mode 1, the network assigns additional PDU session anchors to the PDU session based on the local policy. Further PDU session anchors are released or allocated. The user terminal does not expect that additional IPv6 prefixes will be maintained during the lifetime of the PDU session. SSC mode 1 can be applied to any PDU session type or any access type.

(2) SSC mode 2

If the PDU session in SSC mode 2 has a single PDU session anchor, the network may trigger the release of the PDU session and instruct the user terminal to immediately establish a new PDU session to the same data network. The trigger condition depends on an operator policy (e.g., a request from an application function based on load conditions). When a new PDU session is established, a new UPF device acting with the PDU session anchor may be selected.

On the other hand, if a PDU session in SSC mode 2 has multiple PDU session anchors (e.g., in the case of an uplink delimiter applied to a PDU session in SSC mode 2 or a multi-home PDU session), additional PDU session anchors May be released or allocated.

SSC mode 2 can be applied to any PDU session type and any access type. In the uplink delimiter mode, the user terminal does not participate in the relocation procedure of the PDU session anchor, so that the presence of a plurality of PDU session anchors is not visible to the user terminal.

(3) SSC mode 3

For a PDU session in SSC mode 3, before the connection between the user terminal and the previous PDU session anchor is released, the network is allowed to establish connectivity of the user terminal to the same data network via the new PDU session anchor allow. When applying trigger conditions, the network may determine whether to select an appropriate PDU session anchor for new conditions of the user terminal (e.g., a point of attachment of the network).

SSC mode 3 applies to any PDU session type or any access type.

For a PDU session of IPv4 or IPv6 type, the following applies during the change of the PDU session anchor:

I) The new IP prefix anchored at the new PDU session anchor is allocated within the same PDU session depending on the IPv6 multi-home. Ii) Alternatively, a new IP address or a new IP prefix may be allocated within the new PDU session triggered by the user terminal to establish.

After a new IP address or a new IP prefix is assigned, the existing IP address or the existing IP prefix is maintained for a specified time indicated on the user terminal and released thereafter.

If the PDU session in SSC mode 3 has a plurality of PDU session anchors (e.g., in the case of multi-home PDU sessions, or in the case of an uplink delimiter applied to a PDU session in SSC mode 3) Or may be assigned.

<SSC mode selection>

The SSC mode selection policy is used to determine (i) the type of session or (ii) the type of session and service continuity mode (SSC mode) associated with a group of applications or applications for the user terminal.

It is possible for the operator to provide the SSC mode selection policy to the user terminal. The SSC mode selection policy may include one or more SSC mode selection policy rules that the user terminal may use to determine the type of SSC mode associated with the application or groups of applications. The SSC mode selection policy may include a default SSC mode selection policy rule matching all applications of the user terminal.

When an application requests data transfer (e.g., opens a network socket) and the application can not specify the SSC mode by itself, the user terminal may select the SSC mode associated with the application using the SSC mode selection policy. Additional operations applied to the user terminal and the network are described below.

a) If the user terminal has already established PDU session matching the SSC mode associated with the application, then the user terminal will not be allowed to use the already established PDU session, Routes the application's data within the PDU session. Conversely, if the user terminal does not have an already established PDU session matching the SSC mode associated with the application, the user terminal may request to establish a new PDU session matching the SSC mode associated with the application.

b) The SSC mode associated with the application is either the SSC mode included in the non-default SSC mode selection policy rule that matches the application, or the SSC mode included in the default SSC mode selection policy rule. If the default mode selection policy rule is not included in the SSC mode selection policy and any other SSC mode selection policy rule does not match the application, the user terminal may request a PDU session that does not provide the SSC mode. In this case, the network can determine the SSC mode of the PDU session.

The SSC mode selection policy rules provided by the user terminal may be updated by the operator.

The SMF device receives a list of SSC modes per DNN (Data Network Name) and a default SSC mode as part of the subscription information from a Unified Data Management (UDM) device.

If the user terminal provides the SSC mode when a new PDU session is requested, the SMF device can either accept the requested SSC mode based on the subscription or local configuration, or modify the requested SSC mode, Select the mode.

If the user terminal does not provide SSC mode when a new PDU session is requested, the SMF device may apply the local configuration to select the default SSC mode for the data network listed in the subscription or to select the SSC mode.

When a static IP address / IP prefix is assigned to a PDU session, SSC mode 1 sends a PDU session &lt; RTI ID = 0.0 &gt; (SSN) &lt; / RTI &gt; based on a static IP address / IP prefix subscription for DNN (Data Network Name) and S- NSSAI Lt; / RTI &gt;

<Update on location reporting based on area of interest>

&Quot; When the AMF is subscribed to the area of interest by the SMF and the area of interest is smaller than the registration area transmitted to the UE ", the registration area update (and handover in CM-CONNECTED mode) It is not enough to track what you are doing, so you can explain the case where a location report is needed. However, it does not cover all the appropriate cases. 5 illustrates, in accordance with one embodiment, the four cases illustrate the relationship between the registration area and the area of interest. According to one embodiment, location reporting is required for all cases, but it is not necessary for all four cases, especially Case 2 (the registration area includes the entire area of interest) and case 4 (the registration area is intersecting some areas of interest) .

&Lt; Session management: UE location change notification >

When the PDU session is established or modified, or when the user plane path is changed (e.g., UPF relocation), the SMF may determine the area of interest and subscribe to the AMF notification based on, for example, the UPF service area. When the AMF detects whether the UE moves into or out of the area of interest, it is necessary to notify the SMF of the new location of the UE.

The SMF subscribes to the "UE mobility event notification" service provided by the AMF. During the subscription, the SMF provides an area of interest to the AMF. The AMF sends the new location of the UE to the SMF when the AMF detects that the UE is moving into or out of the area of interest.

In the case of LADN, the SMF provides the LADN DNN to the AMF to subscribe to the notification service when the UE enters the LADN service area. The AMF informs the SMF when the AMF detects that the UE has entered or exited the LADN service area.

The subscription may be maintained for the lifetime of the PDU session regardless of the UP activation state of the PDU session (e.g., activation or deactivation of the PDU session UP connection).

Upon receiving a new UE location notification from the AMF, the SMF determines how to process the PDU session, such as relocation of the UPF, release of the PDU session, deactivation of the user plane connection to the PDU session, and so on.

The SMF determines a new area of interest and sends a new subscription to the AMF in the area of interest. SMF cancels the subscription to the "UE mobility event Notification" service when the PDU session is released. The UE location change notification may also be subscribed by another NF.

<Support for Edge Computing>

Edge computing allows operators and third services to be hosted close to the access points of the UE, thereby achieving efficient service delivery through reduced end-to-end latency and load on the transport network.

The 5G core network selects a UPF near the UE and performs traffic conditioning from the UPF to the local data network via the N6 interface. This may be based on the subscription data of the UE, the UE location, information from the AF (Application Function), policies or other relevant traffic rules.

Due to user or application function mobility, service or session continuity may be required depending on the requirements of the service or 5G network. The 5G core network can expose network information and performance to the Edge Computing Application Function.

Features that support edge computing are: i) User plane (re-selection): The 5G core network selects the UPF to route user traffic to the local data network. Ii) Local Routing and Traffic Tuning: The 5G core network selects the traffic to route to applications in the local data network. This includes the use of a single PDU session with multiple PDU session anchors (UL CL / IP v6 multi-home). Iii) Session and service continuity to enable UE and application mobility. Iv) Application functions may affect UPF (re-selection) and traffic routing via PCF or NEF. V) Network performance exposure: 5G core network and application functionality providing information to each other directly or via NEF. Vi) QoS and Billing: The PCF provides rules for QoS control and billing for traffic routed to the local data network. • Support for local area data networks: The 5G core network provides support for connecting to LADNs in specific areas where applications are deployed.

<Network function description: AMF>

AMF includes the following functions. Some or all of the AMF functionality may be supported in a single instance of AMF.

1) Termination of the RAN CP interface (N2). 2) - Termination of the NAS (N1), NAS encryption, and integrity protection. 3) Registration management. 4) Connection management. 5) Reachability management. 6) Mobility management. 7) Legitimate intercept (interface with AMF device events and LI systems). 8) Transmitting SM message between user terminal and SMF device. 9) A transparent proxy for routing SM messages. 10) Access authentication. 11) Authorization. 12) Providing SMS message transmission between user terminal and SMSF. 13) Security Anchor Function (SEAF). AUSF and the user terminal, and receives the intermediate key established as a result of the user terminal authentication process. For USIM-based authentication, the AMF device retrieves security data from the AUSF. 14) Security Context Management (SCM). The SCM receives the key used to derive the access network unique key from the SEAF. 15) Location Service Management for Regulatory Services. 16) Transmits location service messages between UE and LMF as well as between RAN and LMF. 17) EPS bearer ID assignment for interworking with EPS.

There is one NAS interface instance per access network between the user terminal and the CN, regardless of the number of network functions, and is terminated at least in one of the network functions implementing NAS security and mobility management.

In addition to the functions of the AMF device described above, the AMF device may include the following functions to support a non-3GPP access network:

I) N2 interface support with N3IWF. Some information (e.g., 3GPP cell identification) and procedures (e.g., handover related) defined through 3GPP access through the interface may not be applied and non-3GPP access specific information not applicable to 3GPP access may be applied. Ii) Support of NAS signaling to user terminal via N3IWF. Some procedures supported by NAS signaling over 3GPP access can not be applied to untrusted non-3GPP (e.g., paging) access. Iii) Support authentication of user terminal connected through N3IWF. Iv) management of mobility, authentication and separate security context states of user terminals connected via non-3GPP access or concurrently connected via 3GPP and non-3GPP access. V) Supports coordinated RM management contexts through 3GPP and non-3GPP access. Vi) Supports a dedicated CM management context for connections over non-3GPP access.

<Network Function Description: SMF>

The SMF device can perform the following functions. All or some of the functions of the SMF device may be supported in a single instance of the SMF device:

I) The SMF device may perform session establishment, modification and release including session management, for example, tunnels holding UPF devices and AN nodes. Ii) The SMF device may perform UE IP address assignment and management (including selective acknowledgment). Iii) The SMF device can perform DHCPv4 (server and client) and DHCPv6 (server and client) functions. Iv) The SMF device may perform IPv6 Neighbor Solicitation Proxying specified in the IETF RFC 4861 function and / or ARP proxying specified in IETF RFC 1027 for Ethernet PDUs. The SMF device may respond to an ARP and / or IPv6 Neighbor Solicitation Request by providing a MAC address corresponding to the IP address sent in the request. V) The SMF device controls and selects UP functionality, including forwarding all ARP / IPv6 Neighbor Solicitation traffic to the SMF device for Ethernet PDU sessions, or controlling the UPF device with proxy ARP or IPv6 Neighbor Discovery Can be performed. Vi) The SMF device may perform traffic steering in the UPF device to route traffic to the appropriate destination. The SMF device may suspend the interfaces to the policy control functions. The SMF device may perform a lawful interception (for SM events and the interface of the LI). Ⅶ) SMF devices can support charging interfaces and support charging data collection. The SMF device may perform control and coordination of the collection of charge data in the UPF device. The SMF device may perform an interruption of the SM parts of the NAS messages. The SMF device may perform Downlink Data Notification. The SMF device may be an initiator of AN specific SM information transmitted from the N2 to the AN via the AMF device. The SMF device can determine the SSC mode of the session. (2) (VPLMN) charge interface and charge data collection, (3) (SM event in VPLMN), (3) And (4) support for interaction with external DNs for the transmission of signaling for authentication / authorization of PDU sessions by external DNs, and The same roaming function can be performed.

In an instance of the network slice, it is not required to support all the functions of the SMF device described above.

<Description of network function: UPF device>

The UPF device can perform the following functions. All or some of the functions of the UPF device may be supported in a single instance of the UPF device:

I) If applicable, the UPF device may function as an anchor point for Intra- / Inter-RAT mobility. The UPF device may perform the function of the external PDU session point of the interconnection to the data network. Ii) The UPF device may perform routing and forwarding of packets. For example, a UPF device may support uplink delimiters that route traffic flows to instances of the data network. The UPF device may support a branching point to support multi-homed PDU sessions. Iii) The UPF device may perform packet inspection. For example, the UPF device may perform application detection based on service data flow templates and additionally additional PFDs received from the SMF device. Iv) The UPF device may perform user plane portions of policy rule enforcement, for example, Gating, redirecting, traffic steering, and the like. UPF devices can perform legitimate intercept (UP collection). The UPF device may perform traffic usage reporting. The UPF device may perform QoS handling for the user plane, e.g., UL / DL rate enforcement, and reflective QoS marking on the DL. The UPF device may perform uplink traffic verification (mapping from the SDF device to the QoS flow). The UPF device may perform downlink packet buffering and downlink data notification triggering. The UPF device may forward or forward one or more "end markers" to the source NG-RAN node. V) The UPF device may perform ARP proxying specified in the IPv6 Neighbor Solicitation Proxying specified in IETF RFC 4861 function and / or IETF RFC 1027 for Ethernet PDUs. The UPF device may respond to an ARP and / or IPv6 Neighbor Solicitation Request by providing a MAC address corresponding to the IP address sent in the request.

In the instance of the user plane function of the network slice, it is not required to support all the functions of the UPF device described above.

<Network function description: PCF>

The Policy Control Function (PCF) includes the following functions: i) It supports an integrated policy framework for governance of network operations. (Ii) Apply the policy rule to the control plane function. Iii) Implement a front end (PCF FE) to access subscription information related to the policy decision of the Unified Data Repository (UDR). For reference, the PCF can access the UDR in the same PLMN as the PCF.

<SMF selection function>

The SMF selection function is supported by AMF and is used to allocate SMFs to manage PDU sessions.

The SMF selection feature of AMF utilizes the network storage function to discover SMF instances when SMF information is not available in other ways, such as locally configured in AMF. NRF provides AMF with the IP address or FQDN of the SMF instance.

The SMF selection function in AMF is applicable to both 3GPP access and non-3GPP access.

During SMF selection, the following factors may be considered: i) the selected data network name (DNN) ii) S-NSSAI. Iii) UDM subscription information (eg, per DNN: whether to allow LBO roaming, or per S-NSSAI: subscribed DNN (s) or (S-NSSAI, subscribed DNN) Operator policy. Ⅴ) Loading condition of the candidate SMF.

The same SMF may be selected if there is an existing PDU session to the UE for the same DNN and S-NSSAI used to derive the SMF. However, for example, different SMFs may be selected to support SMF load balancing or to support SMF shutdown. (For example, SMF no longer processes new PDU sessions).

For home routed roaming, the SMF selection function selects the SMF of VPLMN as well as the HPLMN SMF.

The UDM provides a DN subscription context that allows the UDM to process the PDU session of the visited PLMN (i.e., using the LBO) for the DNN, and optionally the AMF has a roaming agreement with the HPLMN with the visited VPLMN . &Lt; / RTI &gt; The SMF selection function selects the SMF from the visited PLMN. If the SMF of the VPLMN can not be derived for the DNN and network slice, or if the subscription can not process the PDU session in the visiting PLMN using the LBO, both the SMF of the HPLMN and the SMF of the VPLMN are selected and the DNN is changed from the HPLMN to the SMF Can be used to derive the identifier.

If the VPLMN detects that the initially selected SMF does not understand the information in the UE request (for roaming with the LBO), it rejects the N11 message (associated with the PDU session establishment request) with the appropriate N11 cause to trigger the AMF to update the new SMF of the VPLMN And home routing roaming (SMF) of the HPLMN.

<AMF selection>

The AMF selection function is applicable to both 3GPP access and non-3GPP access. The AMF selection function can be supported by 5G-AN (e.g., RAN, N3IWF) and is used to select the AMF for a given UE. The AMF supports the AMF selection function to select the AMF for relocation or because the initially selected AMF is not the proper AMF to service the UE (e.g., due to a change in the allowed NSSAI). Other CP NF (s), e.g., SMF, support the AMF selection function to select AMF from the AMF set when the original AMF serving the UE is not available.

5G AN selects the AMF set and AMF in the AMF set in the following situations: 1) when the UE does not provide 5G-S-TMSI or when providing GUAMI to 5G-AN. 2) If the UE provides 5G-S-TMSI or GUAMI but the routing information (i.e., AMF set ID, AMF identified based on the AMF pointer) that is present in 5G-S-TMSI or GUAMI is not sufficient and / (For example, the UE provides the 5G-S-TMSI with the AMF area ID of another area). 3) The AMF instructed the AN to detect that the AMF (identified by GUAMI) is not available and that the AMF was not identified, and / or that the AMF failed.

The other CP NF selects AMF in the AMF set in the following situations: 4) the AMF does not have the specific AMF identified by the GUAMI (s) available and the CP NF is not notified of the target AMF, and / or If the AMF indicates that the CP NF has detected that the AMF failed.

The AMF selection function in the 5G-AN may consider the following factors to select the AMF set: i) the requested NSSAI. Ii) Local Operator Policy.

The AMF selection function of the 5G AN or CP NF considers the following factors for selecting AMF in the AMF set. I) Availability of candidate AMF. Ii) load balancing for candidate AMFs (e.g., considering the weighting factors of candidate AMFs in the AMF set).

When the 5G-S-TMSI or GUAMI is provided to the 5G-AN by the UE, the AMF set identified by the available AMF set ID and the unavailable AMF pointer (e.g., the AN detects that the AMF failed) 5G-AN uses the AMF set ID to select another AMF from the AMF set considering that the AMF is not available (e.g., inoperable).

If the AMF information is not available by other means, for example, other methods, the AMF selection function of the AMF or other CP NF uses the NRF to discover the AMF instance. The NRF provides the IP address or FQDN of the AMF instance to the AMF or other CP NF. I) The AMF selection function of the AMF or other CP NF uses the GUAMI to search for the AMF instance and the NRF provides the IP address or the FQDN of the AMF instance or a list of candidate AMF instances of the same AMF set with additional information. Ii) The AMF selection function of the AMF uses the AMF Set ID to retrieve the AMF instance, and the NRF provides a list of AMF instances of the same AMF set with additional information (eg, priority).

<Registration Management Procedures>

The user terminal needs to register with the network in order to receive authorization to receive services, to activate reachability, to activate mobility tracking.

When a user terminal performs initial registration with a communication system according to an exemplary embodiment or changes from a CM_CONNECTED mode and a CM_IDLE mode to a new tracking area (TA) outside the registration area of the user terminal, Update), when the user terminal needs to perform a periodic registration update (in accordance with a time period of predetermined deactivation), the user terminal additionally requests the negotiated protocol parameters or performance When there is a need to update capabilities, a registration procedure may be used.

The generic registration call flow described below may be applied to all of these registration procedures, but the periodic registration need not include all the parameters used in other registration cases.

The generic registration call flow described below can be used to emergency register UEs that require emergency services to perform but can not obtain general services from the network. These UEs may be limited to limited service situations as defined in TS 23.122.

During initial registration, a Peripheral Equipment Interface (PEI) may be obtained from the user terminal. The operator of the AMF device can check the PEI with the Equipment Identity Register (EIR). The AMF device can deliver the PEI (IMEISV) to the UDM device, the SMF device and the PCF device, and the UDM device can store this data in the UDR device by Nudr_SDM_Update.

<Deregistration procedures>

The de-registration procedure allows: i) a notification to the network that the UE no longer wishes to access 5GS, and ii) a network informing the UE that it no longer has access to 5GS.

The de-registration request by the UE and the network includes whether the de-register is applied to 3GPP access, non-3GPP access, or both. When the UE is registered with both accesses in the same PLMN, the deregistration message can be sent on any access regardless of the access to which the deregistration is applied.

<Session management procedure: PDU session establishment>

PDU session establishment may correspond to the following: i) UE initiated PDU session establishment procedure. Ii) Network triggered PDU session establishment procedure. At this time, the network sends a device trigger message to the application (s) on the UE side. The payload included in the device trigger request message includes information about which application on the UE side is expected to trigger the PDU session establishment request. Based on the information, the application (s) on the UE side trigger the PDU session establishment procedure.

If the UE is simultaneously registered with the non-3GPP access via N3IWF located in a PLMN different from the PLMN of the 3GPP access, the functional entity is located in the PLMN of the access used to exchange the NAS with the UE for the PDU session.

<Session management procedure: PDU session modification>

The PDU session modification procedure is used when one or more QoS parameters exchanged between the UE and the network are modified.

<Session management procedure: PDU session release>

The PDU session release procedure is used to release all resources associated with a PDU session, including: i) the IP address / prefixes assigned to the IP-based PDU session may include the release of multiple prefixes for multi-homed have. Ii) All UPF resources used in the PDU session (including N3 / N9 termination).

The SMF is careful to notify any entity associated with the PDU session, such as the PCF, DN (e.g., when DN authorization occurs when establishing a PDU session).

<N4 session management procedure>

The N4 session management procedure is used to control the function of the UPF device. The SMF device can create, update and remove the N4 session context from the UPF device. There is the following N4 session management procedure initiated by the SMF device: N4 session establishment procedure, N4 session modification procedure and N4 session release procedure.

1. N4 session establishment procedure

The N4 session establishment procedure is used to create an initial N4 session context for the PDU session in the UPF device. The SMF device allocates a new N4 session ID and provides it to the UPF device. The N4 session ID is stored in the SMF and UPF devices and is used to identify the N4 session context during interaction. The SMF device also stores the relationship between the N4 session ID and the PDU session for the UE.

6 shows an N4 session establishment procedure according to an embodiment.

In step 1, the SMF device receives a trigger to establish a new PDU session or changes the UPF device for an established PDU session.

In step 2, the SMF device sends an N4 session establishment request message to a UPF device that contains structured control information defining how the UPF should behave.

In step 3, the UPF device responds with an N4 session establishment response message containing any information that the UPF device should provide to the SMF device in response to the received control information.

In step 4, the SMF device interacts with the network function that triggered the N4 session establishment procedure.

2. N4 session modification procedure

The N4 session modification procedure is used to update the N4 session context of a PDU session present in the UPF device and is executed between the SMF device and the UPF device each time the PDU session related parameters are modified.

7 illustrates an N4 session modification procedure according to an embodiment.

In step 1, the SMF device receives a trigger to modify an existing PDU session.

In step 2, the SMF device sends an N4 session modification request message to the UPF device, which includes an update to the structured control information defining how the UPF should behave.

In step 3, the UPF device identifies the N4 session context to be modified by the N4 session ID. The UPF device then updates the parameters of the N4 session context according to the list of parameters sent by the SMF device. The UPF device responds with the N4 session modification response message containing any information that the UPF device should provide to the SMF device in response to the received control information.

In step 4, the SMF device interacts with the network entity (e.g., AMF or PCF) that triggered the N4 session modification procedure.

3. N4 session release procedure

The N4 session release procedure is used to remove the N4 session context of an existing PDU session in the UPF device.

8 shows an N4 session release procedure according to one embodiment.

In step 1, the SMF device receives a trigger that removes the N4 session context for the PDU session.

In step 2, the SMF device sends an N4 session release request message to the UPF device.

In step 3, the UPF device identifies the N4 session context to be removed by the N4 session ID and removes the entire session context. The UPF device responds with an N4 session release response message containing information that the UPF device should provide to the SMF device.

In step 4, the SMF device interacts with the network entity (e.g., AMF or PCF) that triggered the N4 session release procedure.

<N4 Reporting Procedures>

9 shows an N4 reporting procedure according to one embodiment.

The N4 reporting procedure is used by the UPF to report events associated with the N4 session for an individual PDU session. The trigger for event reporting is configured in the UPF while the SMF performs the N4 session establishment / modification procedure.

In step 1, the UPF detects that an event needs to be reported. A report trigger includes the following cases:

(1) Usage report.

Usage information is collected in the UPF and reported to the SMF.

(2) Start of traffic detection.

When traffic detection is requested by the SMF and the start of traffic for a Packet Detection Rule (PDR) is detected, the UPF reports the start of traffic detection to the SMF and displays the corresponding traffic PDR rule ID.

(3) Stop of traffic detection.

When traffic detection is requested by the SMF and the end of traffic is detected for the PDR, the UPF reports the stop of the traffic detection to the SMF and displays the corresponding PDR rule ID.

(4) Detection of first downlink data for the user terminal in the CM-IDLE state

If the UPF receives a downlink packet but no N3 / N9 tunnels for downlink data transmission and buffering is performed by the UPF, it reports the first downlink data detection to the SMF for downlink data notification. The UPF also reports the DSCP of the packet when directed by the SMF.

In step 2, the UPF sends an N4 report message (N4 session ID, list of report triggers, list of measurement information) to the SMF.

The report trigger parameter contains the name of the event that triggered the report and the measurement information parameter contains the actual information that the SMF requested the notification.

In step 3, the SMF identifies the N4 session context based on the received N4 session ID and applies the reported information to the corresponding PDU session. The SMF responds with an N4 report ACK message.

&Lt; Change of SSC mode 2 PDU session anchor having another PDU session >

10 is a diagram illustrating a procedure for changing the SSC mode 2 PSA for a PDU session according to an exemplary embodiment.

10 is a procedure illustrating that when a multi-home or UL CL is not applied to a PDU session, it is triggered by the SMF device to change a PDU session anchor serving a PDU session of SSC mode 2 for the UE. This procedure releases the existing PDU session associated with the old PDU session anchor (UPF1 of FIG. 10) and sends a new PDU session anchor (UPF2 of FIG. 10) and a new PDU session to the same data network As soon as possible.

The SMF device determines that the serving UPF device needs to be changed due to an event that can benefit from the change.

The PDU session release procedure with the existing PDU session anchor begins. The SMF device calls Namf_Communication_N1N2MessageTransfer to send N1 SM information to the UE via the AMF device. The PDU session release command message in the N1 SM information includes the PDU session ID and cause indicating that PDU session re-establishment for the same data network is required.

Upon receiving a PDU session release command with a cause indicating that re-establishment of a PDU session to the same data network is required as transmitted above, the UE generates a new PDU session ID and initiates a PDU session establishment procedure. The AMF device selects the SMF device and the SMF device can select a new UPF (i.e., UPF2) for the re-established PDU session in SSC mode 2.

&Lt; Change of SSC mode 3 PDU session anchor with multiple PDU sessions >

11 is a diagram illustrating a procedure for changing an SSC mode 3 PDU session anchor having a plurality of PDU sessions according to an embodiment.

11 shows a procedure triggered by the SMF device to change a PDU session anchor serving a PDU session of SSC mode 3 for the UE. This procedure is controlled by the same SMF device to establish a new PDU session to the same DN using the new PDU session anchor (UPF2 of FIG. 11) and then to create an existing PDU session anchor (UPF1 of FIG. 11) Release the session. The SMF device may determine that it is necessary to reassign the new SMF device.

In step 1, the SMF device may determine that it needs to change the serving UPF device or SMF device.

In step 2, the SMF device calls Namf_Communication_N1N2MessageTransfer (PDU session ID, SMF reallocation requested indication, N1 SM container (PDU session modification command (cause, PDU session release timer)). Where the PDU session ID indicates an existing PDU session to be relocated and the cause is indicative of a PDU session re-establishment for the same data network.

The requested SMF reallocation request indication indicates whether the SMF device has been requested to be reassigned. The release timer value represents the time the network can hold a PDU session.

In step 3, the AMF device forwards the NAS message to the UE.

In step 4, if the UE receives a PDU session modification command, the UE may decide to initiate a PDU session establishment procedure:

In accordance with the SSC mode, the UE generates a new PDU session ID and initiates a PDU session establishment request using the new PDU session ID. The new PDU session ID is included in the NAS request message as the PDU session ID and the existing PDU session ID indicating the existing PDU session to be released is also provided to the AMF device of the NAS request message.

If the SMF reallocation is requested in step 2, the AMF device selects another SMF device. Otherwise, the AMF device sends an N11 message to the same SMF device serving the existing PDU session ID.

The AMF device includes both the PDU Session ID and the existing PDU Session ID in the Nsmf_PDUSession_CreateSMContext Request. The SMF device detects that the PDU session establishment request is related to the trigger in step 2 based on the existence of the existing PDU Session ID in the Nsmf_PDUSession_CreateSMContext Request. The SMF device stores the new PDU session ID and selects a new PDU session anchor (i.e., UPF2) for the new PDU session.

In step 5, the PDU session is terminated when the timer provided in step 1 expires (e.g., when the UE consolidates all traffic on PDU # 2 or the session is no longer needed) Released by the UE at the UE.

<UE Configuration Update>

12 is a diagram illustrating a user terminal configuration update procedure according to an embodiment.

The UE configuration update procedure is used when the AMF wants to change the UE configuration. The related procedure may be applied to information in the UE that does not require negotiation between the UE and the network.

The related procedure may include updating the UE Registration Update to require the UE to perform a registration update procedure to modify parameters that require negotiation (e.g., MICO mode) (e.g., to change to an authorized NSSAI requiring re-registration) Used to trigger the procedure.

If the AMF wishes to update the NAS parameters at the UE requiring UE authorization, the AMF provides an indication to the UE whether or not to grant the command to the UE. AMF can not request approval for the NITZ command. AMF requests approval for NSSAI information (eg allowed NSSAI), 5G-GUTI, TAI list and mobility restrictions.

At step 0, the AMF determines the need for a UE configuration change for various reasons (e.g., UE mobility change, NW policy, UE subscription change) or because the UE needs to perform the registration procedure. If the UE is in CM-IDLE, the AMF triggers a Network Triggered Service Request.

The AMF may include a Handover Restriction List in the N2 message that conveys the UE Configuration Update command to the UE when the service area restriction for the UE is updated.

In step 1, the AMF sends a UE configuration update command to the UE, which includes the UE parameters (5G-GUTI, TAI list, allowed NSSAI, NITZ, mobility restriction, LADN information, UE configuration update cause).

The AMF may include at least one of a 5G-GUTI, a TAI list, an allowed NSSAI, a NITZ (network ID and time zone), a mobility restriction parameter or LADN information if the NAS parameter is to be updated without triggering UE re-registration.

The AMF also includes a UE configuration update command that includes the UE configuration update cause indicating whether the UE will approve the command or is sent to trigger a command re-registration, and re-enrollment and related information (e.g., CM- Registration waiting for re-registration of IDLE).

In step 2, if the UE configuration update cause requests approval of the UE configuration update command, the UE sends a UE configuration update complete message to the AMF. AMF may request approval for all UE configuration updates except NITZ.

At this time, receiving the UE configuration update command without a cause indicating the necessity to perform re-registration may still trigger the registration update procedure by the UE for other reasons.

<Reachability procedures>

The elements of the reachability procedure are used for "SMS via NAS" and UDM initiated Reachability Notification requests. The reachability procedure is applied to UEs in the RRC-IDLE, RRC-Inactive and RRC-Connected states.

There are two procedures required for any service-related entity that need to be notified by the UE's reachability: i) UE reachability notification request procedure; And ii) UE activity notification procedure.

1. UE reachability notification request procedure

13 is a diagram illustrating a procedure for requesting a user terminal reachability notification according to an embodiment.

At step 0, during the registration or subscription update procedure, the UDM informs the AMF of the network function ID (e.g., FQDN) authorized to request notification of the reachability of the UE via the Nudm_UEContextManagement_Registration or Nudm_SubscriberData_Update service operation. By default, the UDM is always authorized.

In step 1, if the service-related entity requests the UDM to provide an indication of UE reachability, the UDM can verify that the entity is authorized to make such a request to the subscriber.

If the entity is not authorized, the request may be rejected (eg, if the requesting entity is recognized as a valid entity but not approved for the subscription), or it may be deleted automatically (eg, If not).

In step 2, the UDM stores the ID of the service-related entity and sets the URRP-AMF parameter to indicate that such a request has been received. If the value of the URRP-AMF parameter changes from "not set" to "set", the UDM can start the Namf_EventExposure_Subscribe_service operation (URRP-AMF) with AMF. The UDM can indicate whether to notify the NF directly.

In step 3, the AMF checks whether the requested entity is authorized to make such a request to the subscriber.

If the entity is not authorized, the request may be rejected (eg, if the request entity is recognized as a valid entity but not approved for the subscriber) or automatically deleted (eg, if the request entity is not recognized ).

If the AMF has an MM context for the user, then the AMF sets URRP-AMF to indicate the need to report UDM information on changes in UE reachability (e.g., if the next NAS activity with the UE is detected time.)

In step 4, if the UE state of the AMF is in the CM-CONNECTED state, the AMF may start the N2 notification procedure with the reporting type set to a single RRC-CONNECTED state notification.

In step 5, when UE reachability exists, the AMF initiates a UE reachability notification using Namf_EventExposure_Notify (SUPI, UE-Reachable) using one of the direct notifications for the UDM or NF. The AMF clears the corresponding URRP-AMF for that UE

For a UE in the CM-IDLE state, there is a " UE reachability " in the next NAS signaling UE activity. In the case of a UE in the CM-CONNECTED state, whenever a UE notification is received from a RAN node indicating that the AMF can reach the UE, or whenever the AMF receives a path change request from a new RAN, there is a " UE reachability & do.

2. UE Activity Notification procedure

14 is a diagram illustrating a user terminal activity procedure, in accordance with one embodiment.

In step 1a, the AMF receives (N1) NAS signaling that implies UE reachability (e. G., A registration request or service request message from the UE)

In step 1b, the AMF receives a (N2) UE notification or (N2) path change request from the RAN.

In step 2a, if the AMF is set to report that it has an MM context for the UE and the URRP-AMF can reach the UE, the AMF initiates a Namf_EventExposure_Notify service operation (SUPI, UE-Reachable) message directly to the UDM or NF . The AMF clears the corresponding URRP-AMF for the UE.

In step 2b, when the UDM receives a Namf_EventExposure_Notify service operation (SUPI, UE-Reachable) message or a Nudm_UEContextManagement_Registration service for a URRP-AMF configured UE, it sends an appropriate notification to the NF (e.g. SMSF or SMS-GMSC) subscribing to the UDM Trigger. The UDM clears the URRP-AMF for the UE.

&Lt; User profile management procedure: Subscriber Data Update Notification to AMF >

Whenever a user profile for a user changes in the UDM and the changes affect the AMF's user profile, the UDM invokes the Nudm_SubscriberDataManagement_UpdateNotification service action to notify the AMF of any changes to the affected AMF. AMF then adds or modifies user profiles.

The Nudm_SubscriberDataManagement_UpdateNotification service operation is used by the UDM to update the subscriber data stored in the AMF.

The AMF starts an appropriate operation according to the changed subscriber data. For example, it includes: i) initiating an AMF-initiated deregistration procedure if the updated subscription data indicates that the UE can not roam in the network; And ii) updating the UE context stored in the AN to modify the subscribed UE-AMBR.

<Location Reporting Procedures>

15 is a diagram illustrating a location reporting procedure according to an embodiment.

The location reporting procedure is used to request the NG-RAN to report where the UE is currently located when the AMF is in the CM-CONNECTED state of the target UE. The need for the NG-RAN to continue reporting is discontinued when the UE transitions to CM-IDLE or the AMF sends a cancellation indication. Location reporting procedures can be used to subscribe to services that require accurate cell identification (eg, emergency services, legitimate intercepts, billing) or services from other NFs.

In step 1, the AMF sends a location report control message to the NG-RAN. The location report control message identifies the UE for which the report was requested, the requested location information and the report type. The requested location information may be a TAI + cell ID. The report type indicates whether the message will trigger a single standalone report on the current cell identity serving the UE, or whether it is intended to start the RAN for reporting whenever the UE changes the cell Or whether to report to the NG-RAN whenever the UE moves into or out of the area of interest. If the report type instructs the NG-RAN to start reporting whenever the UE moves into or out of the area of interest, the AMF also provides the area of interest information requested (i.e., the list of TAIs) in the location report control message.

In step 2, the RAN sends a location report message informing the AMF about the location of the UE including the requested location information. If the UE is in the CM-CONNECTED state with the RRC active state, and the RAN receives the location report control message from the AMF as a report type indicating a single stand-alone report, the RAN performs RAN paging before reporting the location to the AMF. When the UE is in the CM-CONNECTED state with the RRC active state, and the RAN receives the location report control message from the AMF having the report type indicating a continuous report each time the UE changes the cell, Together, it sends a location report message to the AMF that includes the last known location. When the NG-RAN recognizes the location of the UE moving into or out of the area of interest, the NG-RAN instructs the UE to start the NG-RAN together with the location of the UE, Lt; / RTI &gt;

In step 3, the AMF may send a Location Report Cancellation message to inform the RAN that it should terminate the location report for the given UE. This message is only needed if reporting is requested during the reporting period. At this time, no new control signaling is transmitted during active handover but a position report is transmitted during Xn handover.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA) A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute one or more software applications that are executed on an operating system (OS) and an operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer readable medium may include program instructions, data files, data structures, and the like, alone or in combination. Program instructions to be recorded on the medium may be those specially designed and constructed for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Although the embodiments have been described with reference to the drawings, various technical modifications and variations may be applied to those skilled in the art. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI &gt; or equivalents, even if it is replaced or replaced.

Claims (29)

The method comprising: transmitting a Location Reporting Control message requesting a location of a user terminal to an Access Network through an Access and Mobility Management Function (AMF); And
Receiving a location report message according to the location report control message from the access network
Lt; / RTI &gt;
The location report control message includes requested location information or a reporting type,
/ RTI &gt;
Location reporting method performed by the AMF device. The method according to claim 1,
The requested location information includes a TAI (Tracking Area Identifier) + cell ID,
Location reporting method performed by the AMF device. The method according to claim 1,
The reporting type includes:
Wherein the location report control message is indicative of whether to i) trigger a single standalone report on the current cell ID serving the user terminal, or ii) each time the user terminal changes a cell, Indicating whether the user terminal is for initiating a location report, or iii) indicating whether to request a report to the access network whenever the user terminal moves into or out of an area of interest,
Location reporting method performed by the AMF device. The method of claim 3,
If the reporting type is iii) to request a report to the access network whenever the user terminal moves inside or outside the area of interest,
The AMF apparatus provides information on the requested region of interest through the location report control message
/ RTI &gt;
Location reporting method performed by the AMF device. The method according to claim 1,
The AMF device transmits a Cancel Location Reporting message to the access network
&Lt; / RTI &gt;
Location reporting method performed by the AMF device. 6. The method of claim 5,
Wherein the cancel position report message includes an indication of the end of the location report for the user terminal,
Location reporting method performed by the AMF device. 6. The method of claim 5,
The cancel location report message is transmitted when the location report is requested for a predetermined period.
Location reporting method performed by the AMF device. The method of claim 3,
If the location report control message indicates the single autonomous report and the user terminal is CM-CONNECTED in the RRC Inactive state,
Prior to reporting the location to the AMF device, the access network performs RAN paging,
Location reporting method performed by the AMF device. The method of claim 3,
Wherein the location report control message indicates that the access network is continuously reporting each time the user terminal changes a cell and the user terminal is CM-CONNECTED in an RRC active state,
Receiving a location report message including a last known location of the user terminal with a time stamp from the access network,
Location reporting method performed by the AMF device. The method of claim 3,
Wherein the reporting type is one in which the location report control message requests the location report to the access network whenever the user terminal moves inside or outside the area of interest,
Wherein the AMF device receives the location report message including the location of the user terminal when the access network recognizes movement of the user terminal into or out of the area of interest,
Location reporting method performed by the AMF device. Comprising: receiving an Location Reporting Control message requesting a location of a user terminal from an Access and Mobility Management Function (AMF); And
Transmitting a location report message according to the location report control message to the AMF device
Lt; / RTI &gt;
The location report control message includes requested location information or a reporting type,
/ RTI &gt;
A location reporting method performed by an access network. 12. The method of claim 11,
The requested location information includes a TAI (Tracking Area Identifier) + cell ID,
A location reporting method performed by an access network. 12. The method of claim 11,
The reporting type includes:
Wherein the location report control message is indicative of whether to i) trigger a single standalone report on the current cell ID serving the user terminal, or ii) each time the user terminal changes a cell, Indicating whether the user terminal is for initiating a location report, or iii) indicating whether to request a report to the access network whenever the user terminal moves into or out of an area of interest,
A location reporting method performed by an access network. 14. The method of claim 13,
If the reporting type is iii) to request a report to the access network whenever the user terminal moves inside or outside the area of interest,
Wherein the access network receives information on the requested area of interest from the AMF device via the location report control message
/ RTI &gt;
A location reporting method performed by an access network. 12. The method of claim 11,
Wherein the access network receives a Cancel Location Reporting message from the AMF device
&Lt; / RTI &gt;
A location reporting method performed by an access network. 16. The method of claim 15,
Wherein the cancel position report message includes an indication of the end of the location report for the user terminal,
A location reporting method performed by an access network. 16. The method of claim 15,
The cancel location report message is transmitted when the location report is requested for a predetermined period.
A location reporting method performed by an access network. A session management function (SMF) determines a region of interest and provides it to an access and mobility management function device; And
Receiving a new location of the user terminal from the AMF device according to whether the user terminal has moved into or out of the area of interest
Lt; / RTI &gt;
Wherein the ROI is determined based on a UPF service area,
A UE Location Change Notification method performed by an SMF device. 19. The method of claim 18,
The SMF device subscribes to a " UE mobility event notification " service provided by the AMF device,
The service subscription is maintained for the life of the PDU session,
A method of notifying a user terminal location change performed by an SMF device. 19. The method of claim 18,
The SMF apparatus includes:
(I) performing UPF relocation, (ii) releasing a PDU session, or (iii) deactivating a User Plane Connection for a PDU session, as soon as the new location of the user terminal is received.
A method of notifying a user terminal location change performed by an SMF device. 21. The method of claim 20,
Wherein the SMF device determines a new region of interest according to the new location,
A method of notifying a user terminal location change performed by an SMF device. 20. The method of claim 19,
The SMF device may be configured to unsubscribe the " UE mobility event notification " service when a PDU session is released,
A method of notifying a user terminal location change performed by an SMF device. The method comprising: detecting whether an Access and Mobility Management Function (AMF) has moved a user terminal into or out of the ROI; And
Wherein the AMF device notifies a new location of the user terminal to a Session Management Function (SMF) device
Lt; / RTI &gt;
Wherein the region of interest is determined based on a UPF service area,
A method of notifying a user terminal location change performed by an AMF device. 24. The method of claim 23,
The SMF device subscribes to a " UE mobility event notification " service provided by the AMF device,
During the service subscription, the SMF device determines the area of interest and provides it to the AMF device.
A method of notifying a user terminal location change performed by an AMF device. 24. The method of claim 23,
The service subscription is maintained for the life of the PDU session,
A method of notifying a user terminal location change performed by an AMF device. A memory including a processor and instructions readable by the computer is included in an Access and Mobility Management Function (AMF)
When the command is executed in the processor, the AMF apparatus transmits a Location Reporting Control message requesting the location of the user terminal to an access network,
Receiving a location report message according to the location report control message from the access network,
Wherein the location report control message includes requested location information or a reporting type,
Access and Mobility Management Funtion (AMF). The access network including a memory including a processor and instructions readable by the computer,
If the command is executed in the processor, the access network receives a Location Reporting Control message requesting a location of a user terminal from an Access and Mobility Management Function (AMF)
Transmits a location report message according to the location report control message to the AMF device,
Wherein the location report control message includes requested location information or a reporting type,
Access network. A memory containing a processor and instructions readable by the computer is included in a Session Management Function (SMF)
When the command is executed in the processor, the SMF device determines a region of interest and provides it to the access and mobility management functional device,
Receiving a new location of the user terminal from the AMF device according to whether the user terminal has moved into or out of the area of interest,
Wherein the ROI is determined based on a UPF service area,
Session management function device. A memory including a processor and instructions readable by the computer is included in an Access and Mobility Management Function (AMF)
If the command is executed in the processor, the AMF apparatus detects whether the user terminal has moved into or out of the ROI,
Notifying a new location of the user terminal to a Session Management Function (SMF) device,
Wherein the region of interest is determined based on a UPF service area,
Access and mobility management device.

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