KR20220135130A - Method and apparatus for session management in a wireless communication system - Google Patents

Abstract

The present disclosure relates to a communication technique for converging a 5G communication system with IoT technology to support a higher data transfer rate than a 4G system, and a system thereof. The present disclosure can be applied to intelligent services (for example, smart home, smart building, smart city, smart car or connected car, health care, digital education, retail business, security- and safety-related services, etc.) based on 5G communication technology and IoT-related technology. A control signal processing method in a wireless communication system comprises the steps of: receiving a first control signal from a base station; processing the received first control signal; and transmitting a second control signal generated based on the processing, to the base station.

Description

Method and apparatus for session management in a wireless communication system

BACKGROUND This disclosure relates generally to wireless communication systems, and more particularly to apparatus and methods for providing network slicing in a wireless communication system or a mobile communication system.

Efforts are being made to develop an improved 5G communication system or pre-5G communication system in order to meet the increasing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, the 5G communication system or the pre-5G communication system is called a 4G network after (Beyond 4G Network) communication system or an LTE system after (Post LTE) system. In order to achieve a high data rate, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to alleviate the path loss of radio waves and increase the propagation distance of radio waves in the very high frequency band, in the 5G communication system, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) are used. ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network: cloud RAN), an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Technology development is underway. In addition, in the 5G system, the advanced coding modulation (ACM) methods FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), and advanced access technologies FBMC (Filter Bank Multi Carrier), NOMA (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

On the other hand, the Internet is evolving from a human-centered connection network where humans create and consume information to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers, etc. with IoT technology, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) are being studied. In the IoT environment, an intelligent IT (Internet Technology) service that collects and analyzes data generated from connected objects and creates new values in human life can be provided. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, advanced medical service, etc. can be applied to

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, technologies such as sensor network, machine to machine (M2M), and MTC (Machine Type Communication) are implemented by 5G communication technologies such as beamforming, MIMO, and array antenna. will be. The application of a cloud radio access network (cloud RAN) as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

A method for providing network slicing information in a wireless communication system or a mobile communication system.

The present invention for solving the above problems is a control signal processing method in a wireless communication system, the method comprising: receiving a first control signal transmitted from a base station; processing the received first control signal; and transmitting a second control signal generated based on the processing to the base station.

Disclosed are an apparatus and method for more effectively providing network slice (or network slicing) information in a wireless communication system.

1 is a diagram illustrating a structure of a mobile communication system according to an embodiment of the present disclosure.
2 is a diagram illustrating a configuration of a network slice IE related to an embodiment of the present disclosure.
3 is a diagram illustrating a procedure for checking availability according to the number of sessions established for each network slice according to an embodiment of the present disclosure.
4 is a diagram illustrating a procedure for updating availability according to the number of sessions established for each network slice according to an embodiment of the present disclosure.
5 is a diagram illustrating the structure of a terminal according to an embodiment of the present invention.
6 is a diagram illustrating the structure of a network entity according to an embodiment of the present invention.
7 is a view for explaining a terminal registration procedure (Registration procedure) according to an embodiment of the present disclosure.
8 is a diagram illustrating a procedure for reducing the number of terminal registrations according to an embodiment of the present disclosure.
9 is a diagram illustrating a bulk terminal registration update procedure according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in the description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

The present disclosure discloses an apparatus and method for providing a network slice (or network slicing) in a wireless communication system. Specifically, a technique for managing network slice information in a wireless communication system that provides a network slice function will be described through the present disclosure. In addition, a technology for interworking between a wireless communication system and a terminal will be described.

Terms that refer to signals, terms that refer to channels, terms that refer to control information, terms that refer to network entities, and terms that refer to components of devices used in the following description are for convenience of description. it is exemplified Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

In addition, although this disclosure describes various embodiments using terms used in some communication standards (eg, 3rd Generation Partnership Project (3GPP)), this is only an example for description. Various embodiments of the present disclosure may be easily modified and applied in other communication systems.

The 3GPP standard standardized the 5G network system architecture and procedures. Mobile operators can provide various services in the 5G network. In order to provide each service, mobile communication operators need to satisfy different service requirements for each service (eg, delay time, communication range, data rate, bandwidth, reliability, etc.). To this end, the mobile communication operator may configure a network slice and allocate network resources suitable for a specific service for each network slice or for each set of network slices. The network resource may mean an NF (Network Function) or logical resource provided by the NF or radio resource allocation of a base station.

For example, a mobile communication service provider may configure network slice A to provide mobile broadband service, configure network slice B to provide vehicle communication service, and configure network slice C to provide IoT service. That is, in this 5G network, a corresponding service can be efficiently provided to a terminal through a network slice specialized for the characteristics of each service.

1 illustrates a structure of a mobile communication system according to an embodiment of the present disclosure.

Referring to FIG. 1 , a 5G system (5GS, 5G System) may be composed of a terminal (UE), a base station ((R)AN), and a 5G core network (5GC, 5G Core Network).

5G core network is AMF (Access and Mobility Management Function), SMF (Session Management Function), UPF (User Plane Function), PCF (Policy Control Function), UDM (Unified Data Management), NSSF (Network Slice Selection Function), NSACF (Network Slice Admission Control Function), AUSF (Authentication Server Function), UDR (Unified Data Repository), etc. may be configured. The terminal (UE) may access the 5G core network through the base station ((R) AN). Hereinafter, UE may be referred to as a terminal, and (R)AN may be referred to as a base station. In addition, the 5G core network may further include an application function (AF) and a data network (DN).

According to an embodiment, the AMF is a network function (NF) that manages wireless network access and mobility for the terminal.

The SMF is an NF that manages a session for the terminal, and the session information includes QoS (Quality of Service) information, charging information, and packet processing information.

UPF is an NF that handles user traffic (eg User Plane traffic) and is controlled by SMF.

The PCF is an NF that manages an operator policy (PLMN policy) for providing a service in a wireless communication system. In addition, the PCF may be divided into a PCF in charge of an access and mobility (AM) policy and a UE policy, and a PCF in charge of a session management (SM) policy. The PCF in charge of the AM/UE policy and the PCF in charge of the SM policy may be logically or physically separate NFs or may be logically or physically one NF.

UDM is an NF that stores and manages subscriber information (UE subscription) of the terminal.

UDR is an NF or database (Database, DB) that stores and manages data. The UDR may store the subscription information of the terminal and may provide the UDM with the subscription information of the terminal. In addition, the UDR may store operator policy information and provide operator policy information to the PCF.

The NSSF may be an NF that selects network slice instances serving the UE or determines Network Slice Selection Assistance Information (NSSAI).

The NSACF may be an NF that manages the network slice usage situation (eg, the number of registered terminals per network slice, the number of session establishments, etc.) and determines whether to allow the registration and session establishment of the terminal.

The AUSF may be an NF that performs a function to support authentication for 3GPP access and non-3GPP access.

AF may be an NF that provides a function for a service according to the present disclosure.

The DN may refer to a data network capable of providing a service provider service, Internet access, or a third party service.

2 is a diagram illustrating a configuration of a network slice IE related to an embodiment of the present disclosure.

Single-Network Slice Selection Assistance Information (S-NSSAI) defined by 3GPP may be used as a delimiter for classifying network slices. 2 shows an example of such an S-NSSAI IE (Information Element) configuration. One S-NSSAI is SST (Slice/Service Type, 116) used by HPLMN (Home PLMN: Home Public Land Mobile Network), SD (Slice Differentiator, 118) used by HPLMN, and SST (112) used by serving PLMN. ) and SD 114 used in the serving PLMN. In addition, the S-NSSAI IE may further include a field 110 indicating the length of content included in the S-NSSAI IE.

In a non-roaming situation, the SST(112) used by the serving PLMN may be the same as the SST(116) used by the HPLMN, and the SD(114) used by the serving PLMN is the SD used by the HPLMN. (118).

In the roaming situation, the SST 112 used by the serving PLMN may be the SST used by the VPLMN (Visited PLMN), and the SD 114 used by the serving PLMN may be the SD used by the VPLMN.

Each SST and SD value constituting one S-NSSAI may or may not have a value depending on the situation.

Network slice selection assistance information (NSSAI) may consist of one or more S-NSSAIs. Examples of NSSAI, configured NSSAI (or configured S-NSSAIs) stored in the terminal, requested NSSAI (or requested S-NSSAIs) requested by the terminal, allowed NSSAI allowed to be used by the terminal (or allowed S-NSSAIs) , rejected NSSAIs (or rejected S-NSSAIs) for which terminal use is rejected, pending NSSAIs (or pending S-NSSAIs) in the process of whether the terminal is available (permission or rejection), and subscription information stored in UDM Subscribed NSSAI and the like may be included, but this is only an example, and the example of NSSAI is not limited to the above.

The present disclosure proposes an example of a method for managing the number of session establishments per network slice.

The NSACF may store information on the maximum number of sessions for each network slice (identifiable as S-NSSAI) (S-NSSAI subject to NSAC) that is a target of Network Slice Admission Control (NSACF). The S-NSSAI information to be NSAC target may include whether the corresponding slice is the target of the maximum number of terminals control and whether the corresponding slice is the target of the maximum number of sessions control. When a specific slice is an NSAC target (or if a specific slice is an NSAC target related to the maximum number of sessions control), the NSACF transmits the maximum number of sessions per slice information of the slice to other 5G NFs (eg, AMF, SMF, PCF). , UDM, UDR, etc.) and can be stored. Alternatively, the NSACF may receive information on the maximum number of sessions per slice through OAM (O&M).

The NSACF may control the number of sessions currently established for each slice. Controlling the number of currently established sessions may include increasing the number of currently established sessions by one when establishing a new session. In this case, the NSACF may control the number of currently established sessions not to exceed the maximum number of sessions. In addition, the control on the number of currently established sessions may include reducing the number of currently established sessions by one when the established sessions are released.

The NSACF may manage a list of PDU Session IDs of PDU session(s) established in association with the network slice. The NSACF may manage a network slice and a list of UE IDs and a list of PDU Session IDs of PDU session(s) established in association with the network slice. For example, the NSACF may identify one PDU session as a combination of a UE ID and a PDU Session ID (a combination of UE ID and PDU Session ID). Alternatively, the NSACF may manage a list of PDU session IDs (a list of PDU session IDs) established for each UE (per UE, per UE ID) referred to as UE IDs. One PDU session ID may be used as a unique session identifier within one terminal. That is, since different PDU sessions established by different terminals can use the same PDU session ID, one PDU session can be uniquely identified by only the PDU session ID in a network supporting a plurality of terminals. Accordingly, the NSACF may uniquely identify one PDU session by using the UE ID together with the PDU session ID.

In order to increase the number of current establishment sessions, the NSACF may check whether the requested PDU session ID and the PDU session referred to as the terminal ID are already included in the list managed by the NSACF. If it is not included in the list managed by the NSACF, the NSACF may add the requested PDU session ID and the UE ID to the list managed by the NSACF and increase the number of current establishment sessions.

The SMF may perform PDU session establishment of an S-NSSAI subject to NSAC (or a network slice serving as an NSAC target related to the maximum number of sessions control). The SMF may receive information on whether a specific network slice is an NSAC target from another 5G NF (eg, AMF, PCF, UDM, UDR, NSACF, etc.). Alternatively, the SMF may receive information on whether a specific network slice becomes an NSAC target through OAM (O&M).

The SMF may decide to check whether a corresponding network slice is currently available in order to proceed with establishment of a PDU session of a network slice that is an NSAC target.

According to the determination, the SMF may discover and select the NSACF responsible for network slice admission control related to the maximum number of sessions of the corresponding network slice (discovery and selection).

The SMF may transmit an NF (NSACF) discovery request message to the NRF. The NF (NSACF) discovery request message may include network slice information (S-NSSAI) and an indicator indicating that the desired NSACF (target NF, target NSACF) should provide an NSAC function related to the number of sessions control. The NRF can find an NSACF that meets the conditions required by the SMF. The NRF may send an NF (NSACF) discovery response message to the SMF. The NF (NSACF) discovery response message may include NSACF-related information discovered by the NRF.

As another method, NSACF information may be set in the SMF, and NSACF information set in the SMF may be used.

The SMF may send the maximum number of sessions control request message received from the NRF or to the NSACF set in the SMF.

Although the present invention has been written as an SMF operation for convenience of description, an embodiment proposed in the present invention may be performed by AMF.

3 illustrates a procedure for checking availability according to the number of sessions established for each network slice according to an embodiment of the present invention. For convenience of explanation, the SMF is described as the operation of the NF 301 , but the NF 301 according to the present invention may be an AMF.

In step 310, the terminal 300 may transmit a PDU session establishment request message to the SMF 301 via the AMF. The PDU session establishment request message may include at least one of a PDU session ID, a terminal ID, and an S-NSSAI.

In step 315, the SMF 301 is based on at least one of the policy set in the SMF 301 and information received from another 5G NF (eg, AMF, PCF, UDM, UDR, NSACF, etc.). - It is possible to determine whether the NSSAI (or the S-NSSAI received from the AMF) becomes an NSAC target (or becomes an NSAC target related to the number of session establishment control).

If the AMF performs the function of the NF 301 and the S-NSSAI information is not included in the PDU session establishment request message in step 310, the AMF 301 is based on the policy set in the AMF 301. Thus, one S-NSSAI can be selected. AMF 301, S-NSSAI (or AMF) requested by the terminal based on at least one of the policy set in the AMF 301, information received from another 5G NF (eg, PCF, UDM, UDR, NSACF, etc.) It is possible to determine whether the selected S-NSSAI) becomes an NSAC target (or a session establishment number control-related NSAC target).

In step 320 , the SMF 301 may transmit an NF discovery request message to the NRF 303 . The NF discovery request message may include at least one of S-NSSAI and required target NSACF capability information. The required capability of the target NSACF may indicate that the target NSACF should support the NSAC function related to the number of sessions.

The NRF 303 may discover and select a desired target NSACF.

In step 325 , the NRF 303 may transmit an NF discovery request response message to the SMF 301 . The NF discovery request message may include target NSACF-related information selected by the NRF.

In step 330 , the SMF 301 may transmit a slice available request message to the NSACF 302 . The NSACF 302 may be the NSACF 302 selected based on the information received from the NRF 303 by the SMF 301 in step 325 and/or information set in the SMF 301 . The SMF 301 may store the selected NSACF information, and thereafter, if necessary, may perform an interaction with the NSACF (eg, the PDU session release procedure described in FIG. 4 ).

The slice availability request message may include information for uniquely identifying one PDU session. For example, a PDU session ID and a UE ID may be included. In addition, the slice availability request message may include S-NSSAI information.

In step 335, the NSACF 302 may check the number of session establishments of the network slice identified by the S-NSSAI. The NSACF 302 may check whether the received PDU session ID and the PDU session referred to as the terminal ID are already included in the list managed by the NSACF. If it is not included in the list managed by the NSACF 302, the NSACF 302 may add the received PDU session ID and the terminal ID to the list managed by the NSACF, and may increase the number of current establishment sessions.

NSACF 302, based on the maximum number of sessions information set in the NSACF 302 or received from other 5G NFs (eg, AMF, SMF, PCF, UDM, UDR, etc.), control the number of sessions currently established /manageable. For example, it is possible to compare the number of currently established sessions and the maximum number of sessions managed by the NSACF 302 , and determine whether the number of currently established sessions and the maximum number of sessions does not exceed.

In step 340, the NSACF (302) may transmit a slice available response message to the SMF (301).

If the PDU session ID and the PDU session referred to as the terminal ID received in step 330 are not included in the list managed by the NSACF, and the number of currently established sessions does not exceed the maximum number of sessions, the NSACF 302 uses a slice Information indicating that S-NSSAI is available (information indicating that PDU session establishment for S-NSSAI is allowed) may be included in the enable response message.

If the PDU session ID and the PDU session referred to as the terminal ID received in step 330 are not included in the list managed by the NSACF, but the number of currently established sessions exceeds the maximum number of sessions, the NSACF 302 can use the slice The response message may include information indicating that S-NSSAI is unavailable (information indicating that PDU session establishment for S-NSSAI is not allowed).

If the PDU session ID received in step 330 and the PDU session referred to as the terminal ID are already included in the list managed by the NSACF, the NSACF 302 is counted in the slice available response message in step 330. The PDU session requested in step 330 has already been counted. It may include information indicating that it is done or information indicating that S-NSSAI is available (information indicating that PDU session establishment for S-NSSAI is allowed).

In step 345 , the SMF 301 may transmit a PDU session establishment response message to the terminal 300 .

If the SMF 301 receives information indicating that S-NSSAI is available from the NSACF 302 in step 340 (information indicating that PDU session establishment for S-NSSAI is allowed) or information indicating that the requested PDU session has already been counted Upon reception, the SMF 301 may determine that the corresponding network slice is available. Accordingly, the SMF 301 may proceed with the PDU session establishment procedure. When the PDU session establishment procedure has been successfully performed, the SMF 301 may transmit a PDU session establishment approval message to the terminal 300 in step 345 .

If the SMF 301 receives information indicating that S-NSSAI is unavailable (information indicating that PDU session establishment for S-NSSAI is not allowed) from the NSACF 302 in step 340, the SMF 301 ) may determine that the corresponding network slice is currently unavailable. Accordingly, the SMF 301 may decide to reject the PDU session establishment without proceeding. The SMF 301 may transmit a PDU session establishment rejection message to the terminal 300 in step 345 .

4 illustrates a procedure for updating availability according to the number of sessions established for each network slice according to an embodiment of the present invention. For convenience of explanation, the SMF is described as the operation of the NF 301 , but the NF 301 according to the present invention may be an AMF.

In step 415, the SMF 301 may decide to release the established PDU session. The determination is a PDU session release request received from the terminal 300 in step 410 or a request received from another 5G NF (eg, AMF, PCF, UDM, UDR, etc.) (PDU session release request, SM (Session management)) policy termination request, etc.).

According to the method described in the present invention, the SMF 301 may determine whether the S-NSSAI associated with the corresponding PDU session is a network slice that is an NSAC target (or a session establishment number control-related NSAC target).

When the S-NSSAI associated with the PDU session is a network slice that is an NSAC target, the SMF 301 may trigger step 420 .

In step 420 , the SMF 301 may transmit a slice available update request message to the NSACF 302 . The slice available update request message may include information for uniquely identifying a PDU session to be released. For example, a PDU session ID and a UE ID may be included. In addition, the slice available update request message may include S-NSSAI information.

In step 425, the NSACF 302 may update the number of session establishments of the network slice identified as S-NSSAI. The NSACF 302 may check whether the received PDU session ID and the PDU session referred to as the terminal ID are already included in the list managed by the NSACF 302 . If included in the list managed by the NSACF 302, the NSACF 302 may delete the received PDU session ID and the terminal ID from the list managed by the NSACF, and reduce the number of current establishment sessions.

In step 430 , the NSACF 302 may transmit a slice available update response message to the SMF 301 . The slice available update response message may include result information (eg, success, failure, etc.) related to the session establishment number update of the network slice.

The SMF 301 may continue the PDU session release procedure.

If the PDU session release is initiated from the request (step 410) of the terminal 300, the SMF 301 may transmit a PDU session release message to the terminal 300 in step 435.

5 is a diagram illustrating the structure of a terminal according to an embodiment of the present invention.

Referring to FIG. 5 , the terminal may include a transceiver 510 , a controller 520 , and a storage 530 . In the present invention, the controller may be defined as a circuit or an application-specific integrated circuit or at least one processor.

The transceiver 510 may transmit/receive a signal to/from another network entity. The transceiver 510 may receive, for example, system information from a network entity, and may receive a synchronization signal or a reference signal.

The controller 520 may control the overall operation of the terminal according to the embodiment proposed in the present invention.

The storage unit 530 may store at least one of information transmitted and received through the transceiver 510 and information generated through the control unit 520 .

6 is a diagram illustrating the structure of a network entity according to an embodiment of the present invention.

Referring to FIG. 6 , the network entity may include a transceiver 610 , a controller 620 , and a storage 630 . In the present invention, the controller may be defined as a circuit or an application-specific integrated circuit or at least one processor.

The transceiver 610 may transmit/receive signals to and from other network entities. The transceiver 610 may receive, for example, system information from a network entity, and may receive a synchronization signal or a reference signal.

The controller 620 may control the overall operation of the terminal according to the embodiment proposed in the present invention.

The storage unit 630 may store at least one of information transmitted and received through the transceiver 610 and information generated through the control unit 520 .

7 is a view for explaining a terminal registration procedure (Registration procedure) according to an embodiment of the present disclosure.

Referring to FIG. 7 , the terminal 300 according to an embodiment of the present disclosure may access the first base station 700 and the second base station 701 to perform a registration procedure with the AMF 702 . The first base station 700 may be a device supporting 3GPP access. The second base station 701 may be a device supporting non-3GPP (N3GPP) access. The AMF 702 to which the first base station 700 and the second base station 701 are connected may be the same device. Alternatively, the first base station 700 and the second base station 701 may be connected to different AMFs.

In step 710 , the terminal 300 may access the first base station 700 and transmit a registration request message. The registration request message may include information about the requested slice (Requested NSSAI, eg, S-NSSAI A) that the terminal intends to use.

In step 712 , the first base station 700 receiving the Registration Request message according to an embodiment of the present disclosure may select an AMF to transmit the Registration Request based on the Requested NSSAI received from the terminal 300 . For example, the first base station 700 may select an AMF capable of supporting the Requested NSSAI.

In step 714 , the first base station 700 may transmit a Registration Request message to the AMF 702 selected in step 712 . AMF 702 is based on the terminal's requested slice (Requested NSSAI), terminal subscription slice (subscribed S-NSSAI), terminal access network (3GPP Access Network (Access Type)), operator policy (operator policy), the allowed slice ( Allowed NSSAI) can be determined. For example, the AMF 702 may include the request slice (eg, S-NSSAI A) of the terminal in the allowed slice (eg, S-NSSAI A).

In step 716 , the AMF 702 may confirm the slice availability to the NSACF 302 of the 5G core network before determining to allow the slice allowed to the terminal 300 . To this end, the AMF 702 may transmit a Slice Availability request message to the NSACF 302 . In the Slice Availability request message, target slice information (eg S-NSSAI, Requested NSSAI, Allowed NSSAI, subscribed S-NSSAI, etc.), access network information of the terminal (eg 3GPP access), terminal location information (eg TA) etc.) and terminal information (eg, SUPI, 5G-GUTI, etc.) may be included.

In step 718, the NF 302, the slice policy of the target slice (eg, S-NSSAI, Requested NSSAI, Allowed NSSAI, subscribed S-NSSAI, etc.) received from the AMF 702 and the current of the target slice You can check the number of connected terminals.

For example, the NF 302 may check whether the terminal ID (eg, SUPI, 5G-GUTI, etc.) is included in the terminal ID list managed by the NF 302 for monitoring the number of S-NSSAI terminal registrations. In addition, the NF 302 may check whether the access network information is included in the terminal ID list managed by the NF 302 for monitoring the number of S-NSSAI terminal registrations. If the terminal ID and/or access network is not included in the terminal ID list, the NF 302 may include the terminal ID and/or access network in the terminal ID list, and may increase the number of terminals counting. .

In step 720 , the NF 302 may transmit a Slice Availability response message to the AMF 702 . In the Slice Availability response message, target slice information (eg S-NSSAI, Requested NSSAI, Allowed NSSAI, subscribed S-NSSAI, etc.), whether the target slice is available (eg, an indicator indicating available or unavailable) (indication), cause value (cause value), etc.) may be included.

The AMF 702 may determine the allowed slice according to whether the slice received from the NF 302 is available. For example, when a reply from the NF 302 that the slice (S-NSSAI) is available, the AMF 702 may include the slice (S-NSSAI) in the allowed slice. According to another example, for example, when the NF 302 transmits a message indicating that the slice (S-NSSAI) is not available, the AMF 702 does not include the slice (S-NSSAI) in the allowed slice. , the slice (S-NSSAI) may be included in a rejected slice (rejected NSSAI).

In step 722 , the AMF 702 may transmit a response message (Registration Accept or Registration Reject message) to the terminal 300 in response to the Registration Request message received in step 714 . The Registration Accept message may include at least one of an allowed slice (Allowed NSSAI) and a rejected slice (rejected NSSAI). If there is no slice available to the terminal, the AMF 702 may transmit a Registration Reject message.

In step 724 , the first base station 700 may transmit the Registration Accept or Registration Reject message received from the AMF 702 to the terminal 300 .

In step 740 , the terminal 300 may access the second base station 701 and transmit a Registration Request message. The Registration Request message may include a request slice (Requested NSSAI, eg, S-NSSAI A) that the terminal intends to use.

In step 742, the second base station 701 that has received the Registration Request message according to an embodiment of the present disclosure, based on the Requested NSSAI and/or the terminal ID (eg, 5G-GUTI, etc.) received from the terminal 300 Thus, you can select the AMF to which the Registration Request is sent. For example, the second base station 701 may select an AMF that may be referred to as a terminal ID (eg, 5G-GUTI, etc.).

In step 744, the second base station 701 may transmit a Registration Request message to the AMF 702 selected in step 742. AMF 702 based on the terminal's requested slice (Requested NSSAI), terminal subscription slice (subscribed S-NSSAI), terminal access network (non-3GPP AN), operator policy (operator policy), allowed slice (Allowed NSSAI) can be decided In addition, in determining the allowed slice, the AMF 120 may consider the allowed slice and/or the rejected slice determined in steps 710 to 724 . For example, the AMF 702 may include the request slice (eg, S-NSSAI A) of the terminal in the allowed slice (eg, S-NSSAI A).

In step 746 , the AMF 702 may confirm the slice availability to the NF 302 of the 5G core network before determining to allow the slice allowed to the terminal 300 . To this end, the AMF 702 may transmit a Slice Availability request message to the NF 302 . In the Slice Availability request message, target slice information (eg S-NSSAI, Requested NSSAI, Allowed NSSAI, subscribed S-NSSAI, etc.), access network information of the terminal (eg non-3GPP access), terminal location information (eg : TA, etc.) and terminal information (eg, SUPI, 5G-GUTI, etc.) may be included.

In step 748, the NF 302, the slice policy of the target slice (eg, S-NSSAI, Requested NSSAI, Allowed NSSAI, subscribed S-NSSAI, etc.) received from the AMF 702 and the current of the target slice You can check the number of connected terminals.

For example, the NF 302 may check whether the terminal ID (eg, SUPI, 5G-GUTI, etc.) is included in the terminal ID list managed by the NF 302 for monitoring the number of S-NSSAI terminal registrations. In addition, the NF 302 may check whether the access network information is included in the terminal ID list managed by the NF 302 for monitoring the number of S-NSSAI terminal registrations. If the terminal ID and/or access network is included in the terminal ID list, the NF 302 may determine that the terminal is already included in the number of terminal registrations. Accordingly, the counting of the number of terminals may not be increased.

That is, when counting the number of terminal registrations based on the number of terminals, the NF 302 includes the terminal ID received in step 746 in the terminal ID list managed by the NF 302 (the terminal ID in step 718) is included in the list), it is determined that the terminal is already included in the number of terminal registrations, and accordingly, the number of terminals counting may not be increased. In this case, since the terminal is already registered, the message in step 750 may include information indicating that the target slice is available.

Alternatively, when counting the number of terminal registrations based on the number of registrations, the NF 302 includes the terminal ID received in step 746 in the terminal ID list managed by the NF 302 (in step 718, the terminal ID is included in the list), when the access network (non-3gpp access) received in step 746 is not included in the terminal ID list managed by the NF 302 (3GPP access is included in step 718), the terminal registers the terminal It is determined that it is not included in the number, and accordingly, the NF 302 may include the access network in the terminal ID list, and may increase the number of terminals counting. In this case, if the current number of terminals exceeds the maximum number of terminals, the number of terminals counting cannot be increased, the access network may be included in the terminal ID list, and the message of step 750 indicates that the target slice is unavailable. may contain information.

In step 750 , the NF 302 may transmit a Slice Availability response message to the AMF 702 . In the Slice Availability response message, target slice information (eg S-NSSAI, Requested NSSAI, Allowed NSSAI, subscribed S-NSSAI, etc.), whether the target slice is available (eg, an indicator indicating available or unavailable) (indication), cause value (cause value), etc.) may be included.

The AMF 702 may determine the allowed slice according to whether the slice received from the NF 302 is available. For example, when a reply from the NF 302 that the slice (S-NSSAI) is available, the AMF 702 may include the slice (S-NSSAI) in the allowed slice. According to another example, for example, when a reply from the NF 302 that the slice (S-NSSAI) is unavailable, the AMF 702 does not include the slice (S-NSSAI) in the allowed slice, and the A slice (S-NSSAI) may be included in a rejected slice (rejected NSSAI).

In step 752 , the AMF 702 may transmit a response message (Registration Accept or Registration Reject message) to the registration request message received in step 744 to the terminal 300 . The Registration Accept message may include at least one of an allowed slice (Allowed NSSAI) and a rejected slice (rejected NSSAI). If there is no slice available to the terminal, the AMF 702 may transmit a Registration Reject message.

In step 754 , the second base station 701 may transmit the Registration Accept or Registration Reject message received from the AMF 702 to the terminal 300 .

According to an embodiment of the present disclosure, the NF 302 may determine the slice availability for each registration of the UE. Accordingly, even if the terminal 300 requests the same slice (eg, S-NSSAI A) in steps 710 and 740, the availability of the slice may vary depending on the occurrence time of steps 718 to 748. That is, the NF 302 in step 718 determines that the slice (eg, S-NSSAI A) is available, but the NF 302 in step 748 determines that the slice (eg, S-NSSAI A) is unavailable. can do. Accordingly, the AMF 702 may include a corresponding slice (eg, S-NSSAI A) as an Allowed NSSAI in the Registration Accept message transmitted in step 722 and transmit it to the terminal 300 . On the other hand, the AMF 702 may include a corresponding slice (eg, S-NSSAI A) as a rejected NSSAI in the Registration Accept message transmitted in step 752 and transmit it to the terminal 300 .

FIG. 7 sequentially describes a registration procedure of a 3GPP access network and a registration procedure of a non-3GPP access network for the purpose of explaining the present disclosure. have.

8 is a diagram illustrating a procedure for reducing the number of terminal registrations according to an embodiment of the present disclosure.

Referring to FIG. 8 , in step 810 , the AMF 702 may decide to delete the S-NSSAI provided to the terminal in the procedure of FIG. 7 from the Allowed NSSAI.

In step 812, the AMF 702 may determine whether the S-NSSAI determined to be deleted from the Allowed NSSAI in step 810 becomes a target for counting the number of terminal registrations (S-NSSAI subject to Network Slice Admission Control). If it is to be an NSAC target, the AMF 702 may decide to perform a terminal registration number update procedure with the NSACF.

In step 814 , the AMF 702 may transmit a slice availability update request message to the NSACF 302 . The slice availability update request message may include S-NSSAI, UE ID, and current access network information of the UE (eg, 3GPP, Non-3GPP, etc.). In addition, the slice availability update request message may include an indicator that the number of UE registrations should be reduced.

In step 816, the NF 302 may update the number of current access terminals of the received S-NSSAI. For example, when counting the number of terminal registrations based on the number of registrations, the NF 302 may check whether the terminal ID and access network received in step 814 are included in the terminal ID list managed by the NF 302. have. If included, the NF 302 may delete the corresponding terminal ID and access network from the terminal ID list managed by the NF 302 and reduce the number of terminal registrations. That is, when simultaneously accessing the 3GPP access network and the Non-3GPP access network with the same terminal ID, the NF 302 may delete the access network received in step 814 from the terminal ID list managed by the NF 302 .

Alternatively, when counting the number of terminal registrations based on the number of terminals, the NF 302 may check whether the terminal ID and access network received in step 746 are included in the terminal ID list managed by the NF 302 . If included, the NF 302 may delete the corresponding access network from the terminal ID list managed by the NF 302 . However, if other access networks are registered with the same UE ID, the NF 302 may maintain the number of UE registrations without decreasing. That is, when simultaneously accessing the 3GPP access network and the Non-3GPP access network with the same terminal ID, the NF 302 may delete the access network received in step 814 from the terminal ID list managed by the NF 302, Since the terminal is still connected to the network through another access network, the terminal ID is not deleted from the terminal ID list, and the number of terminal registrations can be maintained as it is.

9 is a diagram illustrating a bulk terminal registration update procedure according to an embodiment of the present invention.

Referring to FIG. 9 , in step 910 , the NSACF 302 may transmit an indicator to the AMF 702 that the slice availability check may be delayed (or not early). For example, the NSACF 302 may decide to transmit this indicator to the AMF 702 when the number of currently connected registered terminals is significantly lower than the maximum number of registered terminals. The AMF 702 may store information received from the NSACF 302 .

In step 912 , the AMF 702 may process the registration procedure of the first terminal 900 . During the registration procedure, the AMF 702 may omit the slice availability check procedure based on the indicator received in step 910 . That is, steps 716 to 720 of FIG. 7 may be determined to be performed after step 724 .

In step 914 , the AMF 702 may process the registration procedure of the second terminal 901 . During the registration procedure, the AMF 702 may omit the slice availability check procedure based on the indicator received in step 910 .

The AMF 702 may transmit a slice availability update request message to update the registration terminal to the NSACF 302 in step 916 after completing steps 912 to 914. The slice availability update message includes S-NSSAI, one or more registered UE IDs (a list of UE IDs), that is, the UE ID of the UE 900 and the UD ID of the UE 901, and each UE includes access network information. can

In step 918, the NSACF 302 may update the terminal ID list and the current number of registered terminals managed by the NSACF 302 based on the information received in step 916. For example, the NSACF 302 may add the UE ID of the UE 900 and the UE ID of the UD 901 to the UE ID list. In addition, the NSACF 302 may add the access network of the UE 900 and the access network of the UE 901 to the terminal ID list. The NSACF 302 may increase the number of currently connected terminals by the number of terminals, that is, two.

According to another example, the message of step 916 may include an S-NSSAI, a registered terminal ID, and a plurality of access networks to which the terminal is connected. The NSACF 302 may update the terminal ID list and the current number of registered terminals managed by the NSACF 302 based on the information received in step 916 . For example, the NSACF 302 may add the UE ID to the UE ID list. In addition, the NSACF 302 may add a plurality of access networks (3GPP connection and non-3GPP connection) of the UE to the terminal ID list. The NSACF 302 may increase the number of current access terminals by the number of access networks of the terminal, that is, two.

The embodiments disclosed in the present specification and drawings above are merely specific examples to easily explain the contents of the present disclosure and help understanding, and are not intended to limit the scope of the present disclosure. Therefore, the scope of the present disclosure should be construed as including all changes or modifications derived from the present disclosure in addition to the embodiments disclosed herein as being included in the scope of the present disclosure.

Claims (1)

A control signal processing method in a wireless communication system, comprising:
Receiving a first control signal transmitted from the base station;
processing the received first control signal; and
and transmitting a second control signal generated based on the processing to the base station.

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