Method for on-demand based network slice management in wireless communication system and apparatus therefor

Abstract

A method performed by a terminal in a wireless communication system, according to the present disclosure, may comprise the steps of: transmitting, to a network, a first message requesting on-demand single network slice selection assistance information (S-NSSAI); receiving, from the network, a second message including the on-demand S-NSSAI and an expiration value for driving a slice deregistration inactivity timer; transmitting, to the network, a registration request message including requested NSSAI information including the on-demand S-NSSAI to request the use of the on-demand S-NSSAI; receiving, from the network, a registration accept message allowing the use of the on-demand S-NSSAI; transmitting, to the network, a third message including a request for an always-on PDU session related to the on-demand S-NSSAI and a request to first apply the slice deregistration inactivity timer; and receiving, from the network, a fourth message including always-on PDU session indication information indicating approval of the always-on PDU session related to the on-demand S-NSSAI.

Description

Method for on-demand based network slice management in a wireless communication system and apparatus for the same

[0001] The present disclosure relates to a wireless communication system, and more specifically, to a method and apparatus for on-demand based network slice management in a wireless communication system.

[0002]

[0003] Mobile communication systems were developed to provide voice services while ensuring user mobility. However, mobile communication systems have expanded their scope to include data services as well as voice. Currently, due to the explosive increase in traffic leading to resource shortages and users demanding higher-speed services, more advanced mobile communication systems are required.

[0004] The requirements for next-generation mobile communication systems largely include the ability to accommodate explosive data traffic, a dramatic increase in transmission rates per user, a significantly increased number of connected devices, very low end-to-end latency, and high energy efficiency. To achieve this, various technologies are being researched, such as dual connectivity, massive multiple input multiple output (MMIMO), in-band full duplex, non-orthogonal multiple access (NOMA), super wideband support, and device networking.

[0005]

[0006] The present disclosure aims to provide a method and apparatus for on-demand based network slice management in a wireless communication system.

[0007] The problems to be solved by the present disclosure are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0008]

[0009] A method performed by a terminal in a wireless communication system according to a first embodiment of the present disclosure comprises: transmitting a first message to a network for requesting an on-demand S-NSSAI (Single Network Slice Selection Assistance Information); receiving from the network a second message including an expiration value for driving the on-demand S-NSSAI and a slice deregistration inactivity timer; transmitting to the network a registration request message including requested NSSAI information including the on-demand S-NSSAI to request the use of the on-demand S-NSSAI; and receiving from the network a registration acceptance message allowing the use of the on-demand S-NSSAI. The method may include the step of transmitting a third message to the network, the message including a request for an always-on PDU session associated with the on-demand S-NSSAI and a request for priority application of a slice deregistration inactive timer; and the step of receiving a fourth message from the network, the message including always-on PDU session instruction information indicating an acknowledgment of the always-on PDU session associated with the on-demand S-NSSAI.

[0010] Additionally, a method performed by a network in a wireless communication system according to a first embodiment of the present disclosure comprises: receiving a first message from a terminal for requesting on-demand S-NSSAI (Single Network Slice Selection Assistance Information); transmitting to the terminal a second message including an expiration value for driving the on-demand S-NSSAI and a slice deregistration inactivity timer; receiving from the terminal a registration request message including requested NSSAI information including the on-demand S-NSSAI to request the use of the on-demand S-NSSAI; transmitting to the terminal a registration acceptance message allowing the use of the on-demand S-NSSAI; and receiving from the terminal a third message including a request for an always-on PDU session associated with the on-demand S-NSSAI and a request for priority application of the slice deregistration inactivity timer. and may include the step of transmitting to the terminal a fourth message containing always-on PDU session instruction information indicating an always-on PDU session acknowledgment associated with the on-demand S-NSSAI.

[0011] Additionally, a method performed by a terminal in a wireless communication system according to a second embodiment of the present disclosure comprises: transmitting a first message to a network to request an on-demand S-NSSAI (Single Network Slice Selection Assistance Information); receiving from the network a second message containing an expiration value for driving the on-demand S-NSSAI and a slice deregistration inactivity timer; driving the deregistration inactivity timer based on the expiration value; transmitting to the network a registration request message containing requested NSSAI information including the on-demand S-NSSAI to request the use of the on-demand S-NSSAI; and receiving from the network a registration acceptance message allowing the use of the on-demand S-NSSAI. Based on the operation of the above-mentioned registration cancellation inactive timer, the method may include the step of establishing an always-on PDU session based on allowed NSSAI information unrelated to the above-mentioned on-demand S-NSSAI.

[0012] Additionally, a method performed by a network in a wireless communication system according to a second embodiment of the present disclosure comprises: receiving a first message from a terminal for requesting on-demand S-NSSAI (Single Network Slice Selection Assistance Information); transmitting to the terminal a second message including an expiration value for driving the on-demand S-NSSAI and a slice deregistration inactivity timer; operating the deregistration inactivity timer based on the expiration value; receiving from the terminal a registration request message including requested NSSAI information including the on-demand S-NSSAI to request the use of the on-demand S-NSSAI; and transmitting to the terminal a registration acceptance message allowing the use of the on-demand S-NSSAI. It may include the step of establishing an always-on PDU session based on allowed NSSAI information unrelated to the on-demand S-NSSAI, based on the operation of the registration cancellation inactive timer in mutual interaction with the terminal.

[0013] Additionally, a method performed by a terminal in a wireless communication system according to a third embodiment of the present disclosure comprises: transmitting a first message to a network for requesting an on-demand S-NSSAI (Single Network Slice Selection Assistance Information); receiving from the network a second message containing an expiration value for driving the on-demand S-NSSAI and a slice deregistration inactivity timer; transmitting to the network a registration request message containing requested NSSAI information including the on-demand S-NSSAI to request the use of the on-demand S-NSSAI; receiving from the network a registration acceptance message allowing the use of the on-demand S-NSSAI; and transmitting to the network a third message containing a request for an always-on PDU session associated with the on-demand S-NSSAI. and may include the step of receiving a fourth message from the network rejecting a request for an always-on PDU session associated with the on-demand S-NSSAI.

[0014] Additionally, a method performed by a network in a wireless communication system according to a third embodiment of the present disclosure comprises: receiving a first message from a terminal for requesting an on-demand S-NSSAI (Single Network Slice Selection Assistance Information); transmitting to the terminal a second message containing an expiration value for driving the on-demand S-NSSAI and a slice deregistration inactivity timer; receiving from the terminal a registration request message containing requested NSSAI information including the on-demand S-NSSAI to request the use of the on-demand S-NSSAI; transmitting to the terminal a registration acceptance message allowing the use of the on-demand S-NSSAI; and receiving from the terminal a third message containing a request for an always-on PDU session associated with the on-demand S-NSSAI. and may include the step of transmitting a fourth message to the terminal rejecting a request for an always-on PDU session associated with the on-demand S-NSSAI.

[0015]

[0016] It is effective to provide a method and apparatus for on-demand-based network slice management in a wireless communication system.

[0017] The effects obtained by the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure pertains from the description below.

[0018]

[0019] Figure 1 is a diagram illustrating the structure of a next-generation mobile communication system.

[0020] Figure 2 is a diagram illustrating the concept of network slicing.

[0021] FIG. 3 is a flowchart illustrating the interoperability between a terminal and a network according to a first embodiment of stopping a slice deregistration disable timer associated with the on-demand S-NSSAI proposed in the present disclosure.

[0022] FIG. 4 is a flowchart illustrating the interoperability between a terminal and a network according to a second embodiment that makes it impossible to set up an always-on PDU session associated with the on-demand S-NSSAI presented in the present disclosure.

[0023] FIG. 5 is a flowchart illustrating the interaction operation between a terminal and a network according to a third embodiment in which the network rejects the setting of an always-on PDU session associated with the on-demand S-NSSAI presented in the present disclosure.

[0024] FIG. 6 is a flowchart illustrating an example of an always-on PDU session setup operation related to an on-demand S-NSSAI performed by a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0025] FIG. 7 is a flowchart illustrating an example of an always-on PDU session setup operation associated with an on-demand S-NSSAI performed by a network in a wireless communication system according to one embodiment of the present disclosure.

[0026] FIG. 8 is a drawing illustrating the structure of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0027] FIG. 9 is a drawing illustrating the structure of a base station in a wireless communication system according to one embodiment of the present disclosure.

[0028] FIG. 10 is a drawing illustrating the structure of a network in a wireless communication system according to one embodiment of the present disclosure.

[0029]

[0030] Embodiments of the present disclosure will be described in detail below with reference to the drawings. However, detailed descriptions of known functions or configurations that may obscure the gist of the present disclosure in the following description and the attached drawings are omitted. Additionally, throughout the present disclosure, the term "comprising" any component means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0031] Additionally, terms such as first, second, etc. may be used to describe various components, but said components should not be limited by said terms. Such terms may be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the rights of the present disclosure, the first component may be named the second component, and similarly, the second component may be named the first component.

[0032] The terms used in this disclosure are used merely to describe specific embodiments and are not intended to limit this disclosure. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as “comprising” or “comprising” are intended to specify the existence of the described features, numbers, steps, actions, components, parts, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0033] Unless specifically defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which this disclosure pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this disclosure.

[0034] Figure 1 is a diagram illustrating the structure of a next-generation mobile communication system.

[0035] Referring to FIG. 1, as illustrated, the wireless access network of a next-generation mobile communication system (New Radio, NR) consists of a next-generation base station (New Radio Node B, hereinafter gNB) (110) and an AMF (105, New Radio Core Network). A user terminal (New Radio User Equipment, hereinafter NR UE or terminal) (115) connects to an external network through the gNB (110) and the AMF (105).

[0036] In FIG. 1, the gNB corresponds to the eNB (Evolved Node B) of the existing LTE system. The gNB is connected to the user terminal via a wireless channel (120) and can provide superior service compared to the existing Node B (or eNB). In the next-generation mobile communication system, since all user traffic is serviced through a shared channel, a device is required to collect status information such as the buffer status, available transmission power status, and channel status of user terminals and perform scheduling, and this is handled by the gNB (110). The gNB (110) typically controls multiple cells. To achieve ultra-high-speed data transmission compared to existing LTE, it can support a bandwidth greater than the existing maximum bandwidth, and additionally, beamforming technology can be incorporated by using Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) as the wireless access technology. In addition, an Adaptive Modulation & Coding (hereinafter referred to as AMC) method is applied to determine the modulation scheme and channel coding rate according to the channel conditions of the terminal.

[0037] The access and mobility management function (AMF) (105) performs functions such as mobility support, bearer configuration, and QoS configuration. The AMF (105) is a device responsible for various control functions as well as mobility management functions for terminals, and is connected to multiple base stations. Additionally, the next-generation mobile communication system can be linked with existing LTE systems, and the AMF (105) is connected to the mobility management entity (MME) (125) via a network interface. The MME (125) is connected to the existing base station, eNB (130). A terminal supporting LTE-NR dual connectivity can transmit and receive data while maintaining a connection (135) to both the gNB and the eNB.

[0038] Network Slicing

[0039] Network slicing refers to the division of a single physical network into multiple virtual networks. Each divided network can be operated in a customized and optimized manner for specific application services or subscriber types. Based on cloud computing and virtualization technologies, shared physical network resources can be dynamically and effectively scheduled to logical network slices in response to changing user demands.

[0040] Figure 2 is a diagram illustrating the concept of network slicing.

[0041] Referring to FIG. 2, a 5G network slice consists of a set of network functions and configurations for a specific use case or business model. A single network slice can be formed across several domains, including wireless access networks and core networks where distributed cloud infrastructure and transport networks operate. The fundamental principle of 5G network slice design is to provide only the customized functions necessary to handle the traffic of the specific use case. The network slice possesses the ability to adapt to changing requirements along with the necessary customized capabilities.

[0042] Meanwhile, according to the Next Generation Mobile Networks (NGMN) definition, network slicing consists of three layers: the Service Instance Layer, the Network Slice Instance Layer, and the Resource Layer. The Service Instance Layer represents end-user services, with each service represented by a Service Instance. The Network Slice Instance Layer contains the provided Network Slice Instances and utilizes them to provide the network characteristics required by the Service Instances. The Resource Layer provides all virtual or physical resources and network functions necessary to create Network Slice Instances.

[0043] Network slicing in 3GPP 5G mobile networks, currently being conducted by the IETF DetNet WG, operates based on a core network and is fundamentally based on network slice instance information. A network slice instance refers to a set of information regarding the resources and network function instances required to form a network slice. A single network slice can be utilized across the entire Public Land Mobile Network (PLMN) or across one or more tracking areas (TAs). A single network slice instance may be associated with one or more Single Network Slice Selection Assistance Information (S-NSSAI), and conversely, a single S-NSSAI may be associated with one or more network slice instances.

[0044] In a 3GPP 5G mobile network, a single network slice is identified by a single S-NSSAI. An S-NSSAI consists of an SST (Slice / Service type) and an SD (Slice Differentiator); while the SST must be included in the S-NSSAI, the SD can be included optionally. Currently, as shown in Table 1, a total of five SST types and values ​​are defined as standards in the 3GPP technical specifications. Additionally, a set of one or more S-NSSAIs is referred to as an NSSAI (Network Slice Selection Assistance Information). During the registration process of a 5G mobile network, a terminal uses an NSSAI to request a network slice connection from a core network, and the core network is responsible for authenticating and authorizing this network slice connection request from the terminal.

[0045] Table 1 below shows examples of standardized SST values. Standardized SST values ​​provide a method to establish global interoperability for slicing, enabling PLMNs to more efficiently support roaming use cases for the most commonly used slice / service types.

[0046] Slice / Service TypeSST valueeMBB (enhanced Mobile Broadband)1URLLC (Ultra-Reliable Low Latency Communications)2mIoT (massive IoT)3V2X (Vehicle to Everything)4HMTC (High-performance Machine-Type Communications)5HDLLC (High Data rate and Low Latency Communications)6

[0047] Configuration and Management of NSSAI: The terminal may receive, configure, or store various forms of NSSAI information from the 5G core network. The Configured NSSAI is an NSSAI configured by receiving it from the serving PLMN; the Default Configured NSSAI is an NSSAI configured by receiving it from the Home PLMN; and the Requested NSSAI is an NSSAI used when the terminal requests a connection to a specific network slice from the core network. The Allowed NSSAI is an NSSAI signifying that the core network permits the terminal to connect to a specific network slice. Additionally, the Subscribed S-NSSAI refers to the S-NSSAI included in the subscriber information.

[0048] The terminal may be configured with a default NSSAI that is pre-configured and stored, provided by the core network, or updated. Each S-NSSAI included in the default NSSAI corresponds to an S-NSSAI in the subscriber NSSAI. The S-NSSAI included in the terminal's requested NSSAI refers to the S-NSSAI included in the NSSAI that was previously configured or authorized by the network. Ultimately, the NSSAI or S-NSSAI generally used by the terminal refers to the NSSAI or S-NSSAI that was previously configured or authorized by the network.

[0049] Meanwhile, the terminal and the 5G mobile communication network receive or utilize NSSAI information during the registration process to support and manage network slice connections. First, the terminal generally possesses a pre-configured and stored configuration NSSAI and a permission NSSAI that has been previously authorized by the network for use. If there is no previously authorized NSSAI from the network, there may be no permission NSSAI. To request a connection to a specific network slice, the terminal transmits a request NSSAI information to the network, including it in a Registration Request message, during the registration process. In this case, the request NSSAI information refers to the use of the basic default configuration NSSAI information when neither the configuration NSSAI nor the permission NSSAI is stored in the terminal—that is, when there is no available configuration NSSAI information. If the permission NSSAI is not stored but an available configuration NSSAI is stored, the configuration NSSAI is used as the request NSSAI information. Finally, if an available permission NSSAI is stored, the permission NSSAI is used as the request NSSAI information. The core network verifies the request NSSAI included in the registration request message transmitted by the terminal, and then responds to the terminal by including the configuration NSSAI, permission NSSAI, and rejection NSSAI information in a Registration Accept message. The terminal stores the configuration NSSAI, permission NSSAI, and rejection NSSAI information provided in the Registration Accept message received from the network and uses them when subsequently requesting a network slice connection. However, in the case of the rejection NSSAI, since it is NSSAI information that the network has refused to use, the terminal does not use the rejection NSSAI in principle.Through this registration request process, the terminal and the network mutually provide and configure NSSAI information for supporting and managing network slice connections.

[0050] In addition, when the terminal sends a PDU session formation request message to the network for data transmission, it includes S-NSSAI information regarding the network slice that the application related to data transmission within the stored authorized NSSAI intends to connect to, and the network checks the S-NSSAI information included in the PDU session formation request message sent by the terminal and, if there is no problem, responds with acceptance.

[0051] In addition, if network slicing-related information, including NSSAI, changes due to changes in subscriber information or mobile network policies, the network may notify the terminal of the changed NSSAI information. In this case, the network may provide the changed NSSAI information to the terminal through a Generic UE Configuration Update procedure. To this end, the AMF transmits a Configuration Update Command message to the terminal containing the configured NSSAI, authorized NSSAI, and rejected NSSAI information, and the terminal stores the received configured NSSAI, authorized NSSAI, and rejected NSSAI information. Subsequently, the terminal performs a network slice connection request using the changed NSSAI information.

[0052] In addition, the recent 3GPP release 18 defines an alternative S-NSSAI. An alternative S-NSSAI refers to a compatible / replaceable S-NSSAI (e.g., S-NSSAI#2) when an S-NSSAI (e.g., S-NSSAI#1) is no longer available or is in a congested state. An alternative S-NSSAI may be one of the previously allowed NSSAIs. The network also provides the alternative S-NSSAI to the terminal, and the terminal stores the received alternative S-NSSAI. In this case, the network may provide the alternative S-NSSAI to the terminal using a Generic UE Configuration Update procedure, a PDU Session Establishment procedure, or a PDU Session Modification procedure.

[0053] 3GPP Release 18 defines partially allowed NSSAIs. An existing allowed NSSAI refers to an NSSAI that indicates to the network (AMF and / or SMF) that network slicing services associated with the NSSAI information are permitted for the NSSAI requested by the terminal in the registration area. In this case, the allowed NSSAI applies to PLMNs or all TA lists in the registration area. On the other hand, a partially allowed NSSAI applies to PLMNs or some TA lists in the registration area. Therefore, in some TAs within the registration area, network slicing services associated with the partially allowed NSSAI (e.g., partially allowed NSSAI#1—actually a specific S-NSSAI#1) are permitted, while network slicing services associated with the partially allowed NSSAI are not permitted in other TAs. Updates to this partially permitted NSSAI information are performed based on information provided by the network to the terminal through the Registration Procedure or the Generic UE Configuration Update Procedure. However, the timing of when the network performs the Generic UE Configuration Update Procedure is not clearly defined in the 3GPP technical specifications.

[0054] In addition, 5G systems support Always-on PDU Sessions for rapid data transmission and reception to support low-latency services. When an application on a terminal receiving low-latency services requests a PDU session setup from the network to transmit and receive data, the terminal sends "Always-on PDU session requested" information, indicating the request for an Always-on PDU session, to the network by including it in a PDU session establishment request NAS message. A network supporting Always-on PDU Sessions responds by sending a PDU session establishment acceptance NAS message to the terminal, including "Always-on PDU session required" information, indicating the setup of an Always-on PDU session. Subsequently, the terminal and the network maintain the user-plane resource and context information of the PDU session until the terminal switches to idle mode or the setup is released. Furthermore, the same applies to PDU session modification requests.

[0055] The network may reject the terminal's request to establish an always-on PDU session because it does not support it. When an application on the terminal requests the network to establish a PDU session to transmit and receive data, and sends the "Always-on PDU session requested" information, which indicates the request for an always-on PDU session, to the network by including this information in the PDU session establishment request NAS message, the network that does not support an always-on PDU session responds by sending a PDU session establishment reject NAS message to the terminal, which includes "Always-on PDU session not allowed" information, which indicates that the always-on PDU session establishment is not allowed.

[0056] The following are definitions of terms used in the present disclosure.

[0057] Allowed NSSAI: Indicates the S-NSSAI values ​​that a UE can use in the service-providing PLMN in the current enrollment zone.

[0058] Alternative S-NSSAI: Indicates an S-NSSAI compatible with the S-NSSAI of the allowed NSSAI that the AMF uses to replace the S-NSSAI when the S-NSSAI is unavailable or congested.

[0059] Partially Allowed NSSAI: Represents the S-NSSAI values ​​that terminals in some TAs of the current registration area can use in Serving PLMN or SNPN (Standalone Non-Public Network). Each S-NSSAI in the Partially Allowed NSSAI is associated with a list of TAs that support the S-NSSAI.

[0060] Always-on PDU session: A PDU session that must set up user plane resources whenever switching from 5GMM-IDLE mode to 5GMM-CONNECTED mode. The terminal requests a PDU session to be set up as an always-on PDU session according to instructions from the upper layer, and the network determines whether the PDU session will be set up as an always-on PDU session.

[0061] Configured NSSAI: An NSSAI provisioned to a terminal applicable to one or more PLMNs.

[0062] Network Slice: A logical network that provides specific network functions and characteristics.

[0063] NS-AoS (Network Slice Area of ​​Service): The area where a network slice is available, that is, the area where a terminal can access a specific network slice and receive services, is when more than zero resources are allocated to the network slice of an NG-RAN cell. Depending on the specific network slice, this area may be the entire PLMN, one or more TAs, or one or more cells if the NS-AoS does not match the distributed TAs.

[0064] Pending NSSAI: An NSSAI provided by the service-providing PLMN during the registration process, representing S-NSSAI(s) awaiting network slice-specific authentication and authorization procedures.

[0065] Requested NSSAI: The NSSAI provided by the terminal to the serving PLMN during the registration process.

[0066] Subscribed S-NSSAI: An S-NSSAI based on subscriber information, which is information subscribed to by the terminal for use in the PLMN.

[0067] Target NSSAI: An NSSAI provided by the serving PLMN to the NG-RAN (Next Generation Radio Access Network), which induces the NG-RAN to direct a terminal to a cell that supports the network slice identified by the S-NSSAI of this NSSAI.

[0068] Replacement NSSAI: A list of mapping information between the S-NSSAI to be replaced and the replacement S-NSSAI.

[0069] Default S-NSSAI: The S-NSSAI marked as default among the subscribed S-NSSAIs.

[0070] HPLMN S-NSSAI: An S-NSSAI applicable to HPLMNs without additional mapping by the network. If the terminal has a non-empty list of EHPLMNs (Equivalent Home Public Land Mobile Networks), the HPLMN S-NSSAI is applied without additional mapping to PLMNs where the PLMN code is derived from the IMSI (International Mobile Subscriber Identity), regardless of whether this PLMN is included in the EHPLMN list.

[0071] Mapped S-NSSAI: S-NSSAI mapped to a subscribed S-NSSAI for an HPLMN or subscribed SNPN (in the case of a roaming scenario) or an S-NSSAI of a subscribed non-subscribed SNPN.

[0072] Network slicing information: Information stored in the terminal, consisting of one or more of the following:

[0073] a) NSSAI defaulted to PLMN or SNPN;

[0074] b) NSSAI set for PLMN or SNPN;

[0075] b1) NSSRG information for NSSAI set for PLMN or SNPN;

[0076] b2) S-NSSAI positional validity information for the NSSAI configured for PLMN or SNPN;

[0077] b3) S-NSSAI time validity information for NSSAI configured for PLMN or SNPN;

[0078] c) S-NSSAI(s) mapped to an NSSAI configured for a PLMN or SNPN;

[0079] d) NSSAI pending for PLMN or SNPN;

[0080] e) Mapped S-NSSAI(s) to pending NSSAIs for PLMN or SNPN;

[0081] f) Currently rejected NSSAI for PLMN or SNPN;

[0082] g) Mapped S-NSSAI(s) for NSSAIs rejected for current PLMN or SNPN;

[0083] h) Rejected NSSAI for failed or cancelled NSSAA;

[0084] i) For each access type:

[0085] 1) NSSAI permitted in PLMN or SNPN;

[0086] 2) S-NSSAI(s) mapped to NSSAIs allowed in PLMN;

[0087] 3) NSSAIs currently denied in the registry area;

[0088] 4) S-NSSAI(s) mapped to NSSAIs currently denied in the registry area;

[0089] 5) Rejected NSSAI that has reached the maximum number of UEs;

[0090] 6) S-NSSAI mapping for rejected NSSAIs that have reached the maximum number of UEs;

[0091] 7) Alternative NSSAI for PLMN or SNPN; and

[0092] 8) On-demand NSSAI for PLMN or SNPN; and

[0093] j) 3GPP Access Type:

[0094] 1) NSAG information for NSSAI configured for PLMN or SNPN,

[0095] 2) NSSAI partially permitted for PLMN or SNPN,

[0096] 3) S-NSSAI(s) mapped to NSSAIs partially allowed for PLMN or SNPN,

[0097] 4) NSSAI partially rejected for PLMN or SNPN, and

[0098] 5) S-NSSAI(s) mapped to NSSAIs partially rejected for PLMN or SNPN;

[0099] On-demand NSSAI: A list of on-demand S-NSSAIs and a slice deregistration inactivity timer optionally provided for each on-demand S-NSSAI.

[0100] On-demand S-NSSAI: An S-NSSAI included in an NSSAI configured to be requested only when a terminal supporting network slice usage control uses this S-NSSAI to establish a PDU session for user data transmission.

[0101] Partially rejected NSSAI: Indicates that the network rejects the S-NSSAI in some TAs of the registration area, but not in all TAs. Each S-NSSAI of the partially rejected NSSAI is associated with a list of TAs where the S-NSSAI was rejected.

[0102] Rejected NSSAI: Rejected NSSAI for the current PLMN or SNPN, Rejected NSSAI for the current enrollment region, Rejected NSSAI for failed or terminated NSSAAs, Rejected NSSAI for the maximum number of reached terminals.

[0103] The following briefly explains always-on PDU sessions and network slicing. For a detailed explanation, refer to 3GPP TS 23.501 V18.8.0(3 rd Refer to Section 5.6.13 on page 173 and Section 5.15 on pages 251 through 296 of Generation Partnership Project; Technical Specification Group Services and System Aspects; System architecture for the 5G System (5GS); Stage 2 (Release 18)).

[0104] - Always-on PDU session

[0105] An always-on PDU session is a PDU session that must activate a user plane resource whenever it transitions from CM-IDLE mode to CM-CONNECTED state.

[0106] Under the direction of the upper layer, the terminal may request to set the PDU session as an always-on PDU session. The SMF determines whether the PDU session can be set as an always-on PDU session. In the case of home routed roaming, the V-SMF determines whether the PDU session can be set as an always-on PDU session based on the local policy.

[0107] When a terminal requests to change a PDU session formed in EPS to an always-on PDU session after the first system-to-system change from EPS (evolved packet system) to 5GC (5G core), the SMF determines whether the PDU session can be set to an always-on PDU session according to the procedure described above.

[0108] The terminal must request user plane resource activation for the always-on PDU session even if there is no pending uplink data for this PDU session, or if the service request is triggered for signaling only, or if the service request is triggered for paging response only.

[0109] If a terminal has one or more formed PDU sessions that are not allowed to be always-on by the network, and there is no uplink user data waiting to be transmitted for said PDU session, the terminal must not request to activate user plane resources for said PDU session.

[0110] - Network slicing

[0111] Network slicing functionality is described by referring to Section 5.15.11 of 3GPP TS 23.501 V18.8.0.

[0112] Network slice instances are defined within a PLMN or SNPN and must include the following.

[0113] - Core network control plane and user plane network functions described in Section 4.2 of 3GPP TS 23.501 V18.8.0.

[0114] And in the serving PLMN, at least one of the following:

[0115] - 3GPP TS 38.300 V18.7.0(3 rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; NR and NG-RAN Overall Description; NG-RAN described in Stage 2 (Release 18);

[0116] - Non-3GPP Interworking Function (N3IWF) or Trusted Non-3GPP Gateway Function (TNGF) functions for non-3GPP access networks as described in Section 4.2.8.2 of 3GPP TS 23.501 V18.8.0, or Trusted WLAN Interworking Function (TWIF) functions for trusted WLANs for N5CW (Non-5G-Capable over WLAN (Wi-Fi)) device support as described in Section 4.2.8.5 of 3GPP TS 23.501 V18.8.0;

[0117] - W-AGF function for wired access networks described in Section 4.2.8.4 of 3GPP TS 23.501 V18.8.0.

[0118] 5G systems deployed in PLMNs are 3GPP TS 23.501 V18.8.0, 3GPP TS 23.502 V18.8.0(3 rdGeneration Partnership Project; Technical Specification Group Services and System Aspects; Procedures for the 5G System (5GS); Stage 2 (Release 18)) and 3GPP TS 23.503 V18.8.0 (3 rd To support network slice instance selection in Generation Partnership Project; Technical Specification Group Services and System Aspects; Policy and charging control framework for the 5G System (5GS); Stage 2 (Release 18)), specified procedures, information, and configurations must always be supported.

[0119] Network slice management is 3GPP TS 28.530 V18.2.0(3 rd Refer to Generation Partnership Project; Technical Specification Group Services and System Aspects; Management and orchestration; Concepts, use cases and requirements (Release 18)), and for the provisioning procedures of networks and network slices, refer to 3GPP TS 28.531 V18.8.0(3 rd Refer to Generation Partnership Project; Technical Specification Group Services and System Aspects; Management and orchestration; Provisioning; (Release 18)), and the resource model for resource management is 3GPP TS 28.541 V19.2.0(3 rdGeneration Partnership Project; Technical Specification Group Services and System Aspects; Management and orchestration; 5G Network Resource Model (NRM); See Stage 2 and Stage 3 (Release 19)).

[0120] For support of network slicing for roaming, refer to section 5.15.6 of 3GPP TS 23.501 V18.8.0.

[0121] Network slices may vary depending on supported features and network function optimizations; in this case, such network slices may have S-NSSAIs with different slice / service types, for example (see Section 5.15.2.1 of 3GPP TS 23.501 V18.8.0). Operators may deploy multiple network slices that provide the same functionality but target different UE groups. For example, if they provide different committed services or are dedicated to a customer, these network slices may have S-NSSAIs with the same slice / service type but different slice differentiators (see Section 5.15.2.1 of 3GPP TS 23.501 V18.8.0).

[0122] The network can simultaneously provide services to a single terminal through one or more network slice instances via a 5G-AN (5G-Access Network), regardless of the access type registered with the terminal (i.e., 3GPP access and / or N3GPP access). The AMF instance providing services to the terminal logically belongs to each network slice instance providing services to the terminal. That is, this AMF instance is common to the network slice instances providing services to the terminal.

[0123] The number of concurrent connections of network slice instances per terminal is limited by the number of S-NSSAIs of requested / allowed NSSAIs as described in Section 5.15.2.1 of 3GPP TS 23.501 V18.8.0.

[0124] In addition, it is assumed that an AMF capable of supporting all combinations of S-NSSAIs provided as allowed NSSAIs in all (home or visiting) PLMNs can always be selected.

[0125] The selection of a set of network slice instances for a terminal is typically triggered by the AMF that is first contacted during the registration process through interaction with the Network Slice Selection Function (NSSF), and may lead to a change in the AMF. For a detailed explanation of this, refer to Section 5.15.5 of 3GPP TS 23.501 V18.8.0.

[0126] A PDU session belongs to one specific network slice instance per PLMN. Different network slice instances do not share PDU sessions, but different network slice instances can have slice-specific PDU sessions using the same DNN.

[0127] During the handover procedure, the source AMF selects the target AMF by interacting with the network repository function (NRF) as specified in Section 6.3.5 of 3GPP TS 23.501 V18.8.0.

[0128] Network Slice-Specific Authentication and Authorization (NSSAA) enables network slice-specific authentication as described in Section 5.15.10 of 3GPP TS 23.501 V18.8.0.

[0129] Network Slice Admission Control (NSAC) controls the number of registered terminals per network slice, the number of terminals with at least one PDU session / PDN connection per network slice during EPC interworking, and the number of PDU sessions per network slice as described in Section 5.15.11 of 3GPP TS 23.501 V18.8.0.

[0130] Subscription-based restriction support for network slice simultaneous registration enables controlling the network slices that a terminal can simultaneously register using Network Slice Simultaneous Registration Group (NSSRG) information, as described in Section 5.15.12 of 3GPP TS 23.501 V18.8.0.

[0131] Support for data rate limiting per network slice of a terminal enables the application of the maximum bit rate per network slice of a terminal as described in Section 5.15.13 of 3GPP TS 23.501 V18.8.0.

[0132] Refer to Sections 6.3.6 and 6.3.12 of 3GPP TS 23.501 V18.8.0, respectively, for how N3IWF / TNGF supports slice sets.

[0133] For a description of support for network slice usage control, refer to Section 5.15.15 of 3GPP TS 23.501 V18.8.0.

[0134] For support of partial network slices in the registration area, refer to Section 5.15.17 of 3GPP TS 23.501 V18.8.0.

[0135] For support for network slices with network slice service areas that do not match the deployed trace area, refer to Section 5.15.18 of 3GPP TS 23.501 V18.8.0.

[0136] For support for network slice replacement, refer to Section 5.15.19 of 3GPP TS 23.501 V18.8.0.

[0137] For a description of the identification and selection of network slices, refer to Section 5.15.2 of 3GPP TS 23.501 V18.8.0.

[0138] For details regarding subscriptions including subscription information for network slices, refer to Section 5.15.3 of 3GPP TS 23.501 V18.8.0.

[0139] For details regarding NSSAI configuration and NSSAI storage of the terminal, refer to Section 5.15.4 of 3GPP TS 23.501 V18.8.0.

[0140] For an overview of detailed operations related to network slicing, refer to Section 5.15.5 of 3GPP TS 23.501 V18.8.0.

[0141] For a description of network slicing roaming support, including support for optimized handling of temporarily available network slices and normal release of network slice connections upon slice release, refer to Section 5.15.16 of 3GPP TS 23.501 V18.8.0.

[0142] For a description of network slicing and interoperability with EPS, refer to Section 5.15.7 of 3GPP TS 23.501 V18.8.0.

[0143] For a description of network slice support and availability configuration in PLMN, refer to Section 5.15.8 of 3GPP TS 23.501 V18.8.0.

[0144] For a description regarding the inclusion of operator-controlled NSSAIs when establishing access layer connections, refer to Section 5.15.9 of 3GPP TS 23.501 V18.8.0.

[0145] For a description of authentication and authorization per network slice, refer to Section 5.15.10 of 3GPP TS 23.501 V18.8.0.

[0146] For a description related to network slice entry control, refer to Section 5.15.11 of 3GPP TS 23.501 V18.8.0.

[0147] For a description of subscription-based limit support for simultaneous registration of network slices, refer to Section 5.15.12 of 3GPP TS 23.501 V18.8.0.

[0148] For a description of support for data rate limiting per network slice of a terminal, refer to Section 5.15.13 of 3GPP TS 23.501 V18.8.0.

[0149] For a description of Network Slice AS Group (NSAG) support, refer to Section 5.15.14 of 3GPP TS 23.501 V18.8.0.

[0150] For a description related to support for network slice usage control, refer to Section 5.15.15 of 3GPP TS 23.501 V18.8.0.

[0151] For a description of the optimized handling of temporarily available network slices, refer to Section 5.15.16 of 3GPP TS 23.501 V18.8.0.

[0152] For a description of partial network slice support in the registration area, refer to Section 5.15.17 of 3GPP TS 23.501 V18.8.0.

[0153] For a description related to support for network slicing of service areas that do not match the deployed tracking area, refer to Section 5.15.18 of 3GPP TS 23.501 V18.8.0.

[0154] For a description related to network slice replacement support, refer to Section 5.15.19 of 3GPP TS 23.501 V18.8.0.

[0155] For a description related to support for network slice instance replacement, refer to Section 5.15.20 of 3GPP TS 23.501 V18.8.0.

[0156] Below, the standard document 3GPP TS 24.501 V18.9.0(3 rd This document briefly explains the content related to network slicing in 5GS described in Section 4.6 on pages 96 through 123 of the Generation Partnership Project; Technical Specification Group Core Network and Terminals; Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3; (Release 18)).

[0157] 5GS supports network slicing as described in 3GPP TS 23.501 V18.8.0. Within a PLMN or SNPN, a network slice is identified by an S-NSSAI consisting of a Slice / Service Type (SST) and a Slice Identifier (SD). Including an SD in an S-NSSAI is optional. A set of one or more S-NSSAIs is called an NSSAI. 3GPP TS 23.501 V18.8.0 defines S-NSSAIs and NSSAIs such as the configured NSSAI, requested NSSAI, allowed NSSAI, subscribed S-NSSAI, pending NSSAI, alternate S-NSSAI, and partially allowed NSSAI:

[0158] The following S-NSSAI and NSSAI are defined in 3GPP TS 24.501 V18.9.0:

[0159] a) NSSAI currently rejected for PLMN or SNPN;

[0160] b) NSSAI denied for the current registration area;

[0161] c) NSSAI denied for a failed or cancelled NSSAA;

[0162] d) NSSAI rejected after reaching the maximum number of terminals;

[0163] e) Replacement NSSAI;

[0164] f) Partially rejected NSSAI;

[0165] g) Custom S-NSSAI; and

[0166] h) On-demand NSSAI.

[0167] In a roaming scenario, an NSSAI denied for the current PLMN or SNPN, an NSSAI denied for the current registration area, an NSSAI denied due to reaching the maximum number of terminals, or a partially denied NSSAI includes one or more S-NSSAIs for the current PLMN and also includes a set of mapped S-NSSAIs. The S-NSSAI included in the NSSAI denied for a failed or cancelled NSSAA is an HPLMN S-NSSAI.

[0168] In the case of a PLMN, the serving PLMN can configure the terminal to have the following.

[0169] a) NSSAI configured per PLMN;

[0170] b) NSSRG information if the terminal indicates that it supports subscription-based limits for simultaneous registration of network slice functions;

[0171] c) On-demand NSSAI if the terminal indicates support for network slice usage control functions;

[0172] d) S-NSSAI time validity information if the terminal indicates that it supports S-NSSAI time validity information

[0173] e) If the terminal indicates that it supports S-NSSAI location validity information, S-NSSAI location validity information

[0174] Additionally, the HPLMN can configure a terminal with a single default NSSAI, and if the terminal does not have a configured NSSAI or an allowed NSSAI, the PLMN may consider the default NSSAI to be valid. It is optional for the terminal and the network to each support NSSRG information.

[0175] In the case of SNPN, SNPN can be configured so that terminals that are not registered with SNPN or are not registered with the onboarding service have the following.

[0176] a) Configured NSSAI applicable to SNPN

[0177] b) NSSRG information if the terminal indicates that it supports subscription-based limits for simultaneous registration of the network slice function

[0178] c) S-NSSAI time validity information if the terminal indicates support for S-NSSAI time validity information

[0179] d) On-demand NSSAI if the terminal indicates that it supports network slice usage control features

[0180] e) S-NSSAI location validity information if the terminal indicates that it supports S-NSSAI location validity information.

[0181] Additionally, the credential holder may configure a single default NSSAI associated with the "Subscriber Data List" or a selected item of the PLMN subscription, and the default NSSAI may be considered valid in an SNPN where the terminal has neither a configured NSSAI nor an allowed NSSAI. If the terminal registers for or is registered with an SNPN for onboarding services, the SNPN providing the service must not provide the configured NSSAI to the terminal. Support for NSSRG information by the terminal and the network is optional.

[0182] For the current registration area, allowed NSSAIs and denied NSSAIs are managed independently by access type (3GPP access or non-3GPP access) and apply to the corresponding registration area. If there is no valid registration area for the terminal, the denied NSSAI for the current registration area applies to the tracking area (TA) where the corresponding NSSASI was received. If the registration area contains a tracking area indicator (TA) belonging to another PLMN, the allowed NSSAI, the denied NSSAI for the current registration area, the denied NSSAI for failed or cancelled NSSAIs, and the denied NSSAI due to reaching the maximum number of terminals apply to the corresponding PLMN of this registration area.

[0183] An allowed NSSAI associated with a registration area containing TAIs belonging to mutually equivalent but different PLMNs can be used to form a requested NSSAI for any PLMN belonging to an equivalent PLMN when the terminal is outside the registration area where the allowed NSSAI was received.

[0184] If a network slice-specific authentication and authorization process is initiated or in progress for one or more S-NSSAIs belonging to the requested NSSAI, the S-NSSAI is included in the Pending NSSAI. When the network slice-specific authentication and authorization process for the Pending NSSAI is completed, the Pending S-NSSAI is moved to either the Allowed NSSAI or the Denied NSSAI depending on the outcome of the process. The AMF transmits the Allowed NSSAI, updated via the same access of the requested S-NSSAI, to the terminal. The AMF transmits the Partially Allowed NSSAI, updated only via 3GPP access, to the terminal. The AMF transmits the Denied NSSAI, updated via either 3GPP access or non-3GPP access. The Pending NSSAI is managed regardless of the access type. That is, the Pending NSSAI applies to both the 3GPP access and non-3GPP access of the current PLMN, even if it is transmitted via only one of the access types. If a registration area contains a TAI belonging to a different PLMN, the pending NSSAI applies to the PLMN belonging to this registration area because this TAI corresponds to the same PLMN.

[0185] An NSSAI denied for a current PLMN or SNPN applies to all registered PLMNs or SNPNs regardless of access type. For a registration area consisting only of TAIs belonging to a registered PLMN, the AMF must transmit only the NSSAI denied for the current PLMN. If a UE receives the NSSAI denied for the current PLMN and the registration area also contains TAIs belonging to other PLMNs, the terminal must consider the NSSAI denied for the current PLMN to be applicable to all registered PLMNs.

[0186] A denied NSSAI for a failed or revoked NSSAA includes one or more S-NSSAIs that failed authentication and authorization per network slice or whose authorization was revoked, and applies to all registered PLMNs or SNPNs regardless of access type.

[0187] NSSAIs rejected due to reaching the maximum number of terminals apply to all registered PLMNs or SNPNs and the access type to which the rejected NSSAI was transmitted. If one or more S-NSSAIs indicate that the maximum number of terminals has been reached, the AMF must transmit a rejected NSSAI containing the S-NSSAI with the rejection reason "S-NSSAI unavailable due to reaching the maximum number of terminals". If timer T3526 associated with an S-NSSAI was started upon receiving the NSSAI rejected due to reaching the maximum number of terminals, when timer T3526 associated with the S-NSSAI(s) expires, the S-NSSAI(s) may be removed from the rejected NSSAI containing the S-NSSAI(s) with the rejection reason "S-NSSAI unavailable due to reaching the maximum number of terminals". If one or more S-NSSAIs are removed from the NSSAI rejected due to reaching the maximum number of terminals, timer T3526 associated with the removed S-NSSAI is stopped, if it is running. If the terminal selects an E-UTRA cell connected to the EPC, the terminal does not stop timer T3526.

[0188] If a terminal receives a rejected NSSAI because the maximum number of terminals has been reached, and the registration area contains a TAI belonging to another PLMN, and this TAI is equivalent to that PLMN, then when the terminal is in this registration area, the terminal must treat the rejected NSSAI because the maximum number of terminals has been reached as applicable to that equivalent PLMN.

[0189] If a terminal indicates that it supports the network slice replacement function and the AMF decides to provide mapping information between the S-NSSAI to be replaced and the replacement S-NSSAI for the terminal, the network must provide the replacement NSSAI to the terminal. The replacement NSSAI is managed independently by access type (3GPP access or non-3GPP access) and applies to the registration area.

[0190] If a terminal indicates that it supports partial network slicing and includes an S-NSSAI in the requested NSSAI, the AMF determines which S-NSSAIs to include in the partially allowed NSSAI or partially denied NSSAI as specified in Section 4.6.2.11 of 3GPP TS 24.501 V18.9.0. When the AMF provides the partially allowed NSSAI and the partially denied NSSAI to the terminal, each S-NSSAI must belong to either the partially allowed NSSAI or the partially denied NSSAI, and must not belong to both. The number of S-NSSAIs included in the partially allowed NSSAI or the partially denied NSSAI shall not exceed 7. The sum of the number of S-NSSAIs stored in the partially allowed NSSAI and the partially allowed NSSAI shall not exceed 8. The partially allowed NSSAI applies only to 3GPP access and applies to the registration zone. The partially denied NSSAI applies only to 3GPP access and applies to the registration zone.

[0191] According to a local policy, when a terminal attempts to register with a slice identified by a specific S-NSSAI, the terminal may remove the corresponding S-NSSAI from the rejected NSSAI for failed or cancelled NSSAAs.

[0192] Depending on the network local policy, when a terminal requests an S-NSSAI based on the local policy, the AMF can initiate network slice-specific authentication and authorization procedures for S-NSSAIs regarding failed or cancelled NSSAAs and denied NSSAIs.

[0193] To ensure that at least one PDU session can be established to access the service even if network slice-specific authentication and authorization fails, it is recommended that at least one S-NSSAI in the default configured NSSAI, or at least one default S-NSSAI, not be subject to network slice-specific authentication and authorization.

[0194] It is recommended to have at least one S-NSSAI that is not subject to network slice entry control, or at least one default S-NSSAI. This allows for the establishment of at least one PDU session to access the service.

[0195] Denied NSSAI can be provided on the network via Denied NSSAI IE or extended Denied NSSAI IE.

[0196] Network slicing in terms of mobility management is briefly explained. For details, refer to Section 4.6.2 of 3GPP TS 24.501 V18.9.0.

[0197] When registering with a PLMN or SNPN, excluding the registration procedure for periodic registration renewal, initial registration for the SNPN onboarding service, and the registration procedure for mobility registration renewal when registering for the SNPN onboarding service, in the following cases, the terminal must send to the AMF the requested NSSAI corresponding to the network slice to be registered, which includes one or more S-NSSAIs among the NSSAIs allowed for the requested PLMN or SNPN or the NSSAIs configured for the PLMN or SNPN:

[0198] a) If the terminal currently has an NSSAI configured for the PLMN or SNPN

[0199] b) The terminal currently has an NSSAI allowed for the PLMN or SNPN, or

[0200] c) Where the terminal does not have an NSSAI allowed for the current PLMN or SNPN, nor does it have an NSSAI configured for the current PLMN or SNPN, but has an NSSAI configured by default. In this case, the terminal informs the AMF that the requested NSSAI was generated from the NSSAI configured by default.

[0201] In a roaming scenario, if a mapped S-NSSAI associated with an allowed NSSAI or a configured NSSAI is missing, the terminal must set a locally mapped S-NSSAI to the same value as the received S-NSSAI. Additionally, if the terminal receives a denied NSSAI IE (information element) or an extended denied NSSAI IE without an associated mapped S-NSSAI, and the denied NSSAI is different from the denied NSSAI of a failed or cancelled NSSAA, the terminal must set a locally mapped S-NSSAI to the same value as the received S-NSSAI.

[0202] The above description occurs only when the terminal is roaming and does not provide the terminal with an AMF that conforms to the specifications of the previous version, which is mapped to one or more S-NSSAIs in an allowed NSSAI or configured NSSAI.

[0203] Except for the S-NSSAI included in the NSSAI described above, the requested NSSAI may be formed based on the S-NSSAI present in the terminal (for details, see clause 5.5.1.3.2 of 3GPP TS 24.501 V18.9.0). In a roaming scenario, the terminal must also provide a mapped S-NSSAI for the requested NSSAI.

[0204] Even if the terminal does not receive an S-NSSAI mapped to one or more S-NSSAIs in an allowed NSSAI or configured NSSAI, the terminal uses the S-NSSAI received from the serving network for all NAS messages. In this case, the terminal does not need to set up a locally mapped S-NSSAI.

[0205] The AMF checks whether the requested NSSAI is allowed based on the subscribed S-NSSAI in the terminal subscription, and in roaming scenarios, checks based on the mapped S-NSSAI provided by the terminal. The AMF must provide the terminal with the NSSAI allowed for the PLMN or SNPN, and must also provide the terminal with the S-NSSAI(s) mapped to the NSSAI allowed for the PLMN or SNPN. Additionally, if the AMF allows one or more subscribed S-NSSAIs for the terminal, the AMF may include the allowed subscribed S-NSSAI in the Allowed NSSAI of the registration acceptance message. The AMF must ensure that the S-NSSAI of the Allowed NSSAI is not mapped to the same S-NSSAI of the HPLMN or subscribed SNPN.

[0206] If a) all S-NSSAIs included in the requested NSSAI are denied or the requested NSSAI is not included in the UE, b) all basic S-NSSAIs are not allowed, c) the terminal cannot register for the SNPN's onboarding service or is not registered for the onboarding service, or the terminal cannot register for the emergency service or is not registered for the emergency service, the AMF may deny the registration request (for details, see 5.5.1.2.5 and 5.5.1.3.5 of 3GPP TS 24.501 V18.9.0).

[0207] In a roaming scenario, if the mapped S-NSSAI associated with the requested NSSAI is missing, the AMF must set the locally mapped S-NSSAI to the same value as the received S-NSSAI.

[0208] In a roaming scenario, if the terminal complies with the specifications of a previous version, or if the service network does not provide an S-NSSAI mapped to one or more S-NSSAIs in an allowed NSSAI or a configured NSSAI, the terminal may omit the S-NSSAI mapped to one or more S-NSSAIs in the requested NSSAI.

[0209] The network slice set for a terminal may be changed at any time while the terminal is registered with the PLMN or SNPN, and the change may be initiated by the network or the terminal. In this case, the allowed NSSAI and associated registration areas may be changed during the registration procedure or the general terminal configuration update procedure. The configured NSSAI and the denied NSSAI may be changed during the registration procedure or the general terminal configuration update procedure. The default configured NSSAI may be changed by sending a UE parameters update transparent container to the terminal during the NAS transmission procedure. The pending NSSAI may be changed during the registration procedure. Additionally, the network may trigger the registration procedure to update the allowed NSSAI using the general terminal configuration update procedure.

[0210] When 5GS registration type IE indicates "mobility registration updating", and the procedure does not initiate a change to the slice in which the terminal is currently registered, and the terminal is still in the current registration area, the terminal in NB-N1 mode does not include the NSSAI requested during the registration procedure.

[0211] When registering a 5GS registration type IE indicating "Mobility Registration Renewal" for a terminal in NB-N1 mode, the AMF does not include an allowed NSSAI, except where the allowed NSSAI for the terminal has changed.

[0212] If the 5GS registration type IE indicates "SNPN onboarding registration" or the terminal is registered with SNPN's onboarding service, the terminal does not contain the NSSAI requested during the registration process. The AMF does not contain the NSSAI allowed during the registration process if the 5GS registration type IE indicates "SNPN onboarding registration" or the terminal is registered with SNPN's onboarding service.

[0213] The terminal considers the last received allowed NSSAI to be valid until it receives a new allowed NSSAI.

[0214] For details regarding NSSAI storage, refer to Section 4.6.2.2 of 3GPP TS 24.501 V18.9.0.

[0215] For details regarding the provision of NSSAI to lower layers in 5GMM-IDLE mode, refer to Section 4.6.2.3 of 3GPP TS 24.501 V18.9.0.

[0216] For details regarding authentication and authorization per network slice, refer to Section 4.6.2.4 of 3GPP TS 24.501 V18.9.0.

[0217] For details regarding mobility management based on network slice acknowledgment control, refer to Section 4.6.2.5 of 3GPP TS 24.501 V18.9.0.

[0218] For details regarding the provision of NSAG information for lower layers, refer to Section 4.6.2.6 of 3GPP TS 24.501 V18.9.0.

[0219] For details regarding mobility management for the optimized processing of temporarily available network slices, refer to Section 4.6.2.8 of 3GPP TS 24.501 V18.9.0.

[0220] For information regarding mobility management based on network slice usage control, refer to Section 4.6.2.9 of 3GPP TS 24.501 V18.9.0.

[0221] For matters related to mobility management aspects of handling network slices using NS-AoS that do not match the deployed tracking area, refer to Section 4.6.2.10 of 3GPP TS 24.501 V18.9.0.

[0222] For details regarding mobility management for partial network slices, refer to Section 4.6.2.11 of 3GPP TS 24.501 V18.9.0.

[0223] Network slicing in terms of session management is briefly described. For details, refer to Section 4.6.3 of 3GPP TS 24.501 V18.9.0.

[0224] To enable PDU transmission in a network slice, if a PDU session suitable for PDU transmission is not established, the terminal may request the establishment of a PDU session in a network slice toward a data network (DN) associated with an S-NSSAI and a data network name (DNN). The included S-NSSAI is part of the allowed NSSAI of the service provider PLMN or SNPN. This is an S-NSSAI value valid in the service provider PLMN or SNPN, and in roaming scenarios, a mapped S-NSSAI is also included in the PDU session where possible. For details, refer to Section 6.4.1 of 3GPP TS 24.501 V18.9.0.

[0225] The terminal, where S-NSSAI is present (see Section 6.2.9 of 3GPP TS 24.501 V18.9.0), according to URSP rules containing S-NSSAI or 3GPP TS 24.526 V18.8.9 (3 rd As described in Section 4.2.2 of Generation Partnership Project; Technical Specification Group Core Network and Terminals; User Equipment (UE) policies for 5G System (5GS); Stage 3; (Release 18)), the terminal determines whether to establish a new PDU session or use one of the established PDU sessions based on the terminal's local configuration.

[0226] For information regarding session management-based network slice entry control, refer to Section 4.6.3.1 of 3GPP TS 24.501 V18.9.0.

[0227] For details regarding support for network slice entry control and interoperability with EPC, refer to Section 4.6.3.2 of 3GPP TS 24.501 V18.9.0.

[0228] For information regarding session management-based network slice data rate limiting control, refer to Section 4.6.3.3 of 3GPP TS 24.501 V18.9.0.

[0229] For information regarding session management based on network slice replacement, refer to Section 4.6.3.4 of 3GPP TS 24.501 V18.9.0.

[0230] For details regarding session management for optimizing the processing of temporarily available network slices, refer to Section 4.6.3.5 of 3GPP TS 24.501 V18.9.0.

[0231] For details regarding partial network slice session management, refer to Section 4.6.3.6 of 3GPP TS 24.501 V18.9.0.

[0232] For details regarding session management aspects related to handling network slices with NS-AoS that do not match the deployed trace area, refer to Section 4.6.3.7 of 3GPP TS 24.501 V18.9.0.

[0233] If a 3GPP network and a terminal support network slice usage control, the terminal may request the network by including an on-demand Single Network Slice Selection Assistance Information (S-NSSAI) in the requested NSSAI of a registration request message. An on-demand S-NSSAI refers to an S-NSSAI that a terminal supporting network slice usage control intends to use to establish a PDU session for specific data transmission. A network supporting network slice usage control provides the on-demand S-NSSAI requested by the terminal by including it in a registration acceptance message and manages the on-demand S-NSSAI. At this time, the network may additionally provide a slice cancellation inactive timer to the terminal, and the terminal activates the slice cancellation inactive timer using the value received from the network. When the slice cancellation inactive timer expires, the terminal may locally remove the on-demand S-NSSAI from the allowed NSSAI. The network also removes the on-demand S-NSSAI from the allowed NSSAI and provides / updates the updated allowed NSSAI information to the terminal through a configuration update command message.

[0234] In particular, for always-on PDU sessions to provide Ultra-Reliable Low Latency Communication (URLLC) services such as Time Synchronization Container (TSC) and Time Sensitive Networking (TSN), once configured, user plane resources must be activated whenever the connection management (CM) transitions from IDLE to CONNECTED. In other words, an always-on PDU session is an important PDU session that must remain active until the session is released.

[0235] However, according to current 3GPP standards, it is unclear how the terminal and the network should operate when an always-on PDU session is established and the related network slicing is based on on-demand S-NSSAI. More specifically, the 3GPP technical standards do not clearly define how the terminal and the network should handle the always-on PDU session and the slice unregistration inactive timer when an always-on PDU session is established and the related network slicing is based on on-demand S-NSSAI. Therefore, the following problem scenarios may occur if the operation follows the current 3GPP standards.

[0236] 1) A terminal and a network on a 5G system support network slice usage control. The terminal requests an on-demand S-NSSAI from the network via a registration request message, and receives an on-demand S-NSSAI and a slice unregister inactive timer from the network via a registration acceptance message, a configuration update command message, or a configuration update completion message.

[0237] 2) To receive specific data services, the terminal establishes an always-on PDU session by performing an on-demand S-NSSAI-related always-on PDU session establishment procedure provided by the network. In addition, the terminal activates a slice unregister inactive timer provided by the network. Furthermore, the network also activates a slice unregister inactive timer and monitors the terminal's network slice usage.

[0238] 3) When the slice registration cancellation inactivity timer expires, the terminal and the network remove the on-demand S-NSSAI information from the allowed NSSAI list and update the allowed NSSAI list by exchanging updated allowed NSSAI information. However, this also releases and disables the on-demand S-NSSAI-based always-on PDU session.

[0239] 4) There may be cases where it is necessary to maintain an always-on PDU session regardless of when the slice cancellation inactivity timer expires, but current 3GPP technical specifications do not describe how the terminal and network handle such cases. If, after the always-on PDU session is released and deactivated due to the expiration of the slice cancellation inactivity timer, the always-on PDU session is reset based on updated allowed NSSAI information, inefficient signaling overhead may occur for resetting the always-on PDU session, and additionally, service continuity based on the always-on PDU session cannot be provided.

[0240] As described above, when setting up an always-on PDU session related to on-demand S-NSSAI according to current 3GPP technical specifications, it is significantly inefficient and may be difficult to guarantee service QoS.

[0241] In conclusion, when network slice usage control between a terminal and a network is supported / enabled / configured, when the PDU session formation procedure or PDU session modification procedure related to the terminal's always-on PDU session is performed based on the on-demand S-NSSAI and slice cancellation inactivity timer operation according to current 3GPP technical specifications, ultra-low latency service connection problems, signaling overhead, and resource waste are caused by inefficient operation, so an efficient and clear solution for this is absolutely necessary.

[0242] As a first embodiment of the present disclosure proposed to address the problem according to the current 3GPP technical specifications, a method of stopping the slice deregistration disable timer associated with the on-demand S-NSSAI may be considered.

[0243] FIG. 3 is a flowchart illustrating the interoperability between a terminal and a network according to a first embodiment of stopping a slice deregistration disable timer associated with the on-demand S-NSSAI proposed in the present disclosure.

[0244] In this disclosure, the network refers to an Access and Mobility Management Function (AMF) or a Session Management Function (SMF).

[0245] According to one embodiment, in a 3GPP network, a terminal and a network can support network slice usage control.

[0246] Referring to FIG. 3, if the terminal supports network slice usage control, the terminal may request on-demand S-NSSAI information from the network using a first message (e.g., a registration request message or a setting update completion message) in operation 310.

[0247] In operation 320, the network may transmit a second message (e.g., a registration acceptance message or a configuration update command message) containing on-demand S-NSSAI information to the terminal in response to a first message requesting on-demand S-NSSAI information transmitted by the terminal. The network then monitors and manages the on-demand S-NSSAI assigned to the terminal. On-demand S-NSSAI refers to an S-NSSAI that a terminal supporting network slice usage control intends to use to establish a PDU session for specific data transmission. The network may additionally provide the terminal with a slice unregister inactive timer expiration value included in the second message. The slice unregister inactive timer expiration value represents the time value from when the slice unregister inactive timer starts its operation until it expires.

[0248] The network, in operation 325, locally triggers the slice unregister inactive timer based on the expiration value.

[0249] The terminal receives a second message containing an on-demand S-NSSAI transmitted by the network. The terminal may additionally receive a slice deregistration inactivity timer expiration value included in the second message. In operation 330, the terminal activates the slice deregistration inactivity timer based on the received slice deregistration inactivity timer expiration value. Here, the slice deregistration inactivity timer is set for the purpose of deregistering a slice by determining that the slice is deactivated if it is not used during the specified time. Therefore, when the slice deregistration inactivity timer expires, the terminal removes the on-demand S-NSSAI from the allowed NSSAI locally. The network also removes the on-demand S-NSSAI from the allowed NSSAI locally and provides the terminal with updated allowed NSSAI information via a configuration update command message. The terminal uses this to update the allowed NSSAI information. Accordingly, if the relevant slice is not used for a certain period of time, the on-demand S-NSSAI is removed from the allowed NSSAI.

[0250] According to one embodiment, the slice unregister inactive timer may operate per on-demand S-NSSAI and PDU session (e.g., PDU session ID). Alternatively, the slice unregister inactive timer may operate separately per on-demand S-NSSAI and general PDU session (e.g., PDU session ID) and per on-demand S-NSSAI and always-on PDU session.

[0251] Devices / User Equipment (UEs) that support network slice usage control can configure 'Network Slice Usage Control Function Support'.

[0252] A terminal that supports network slice usage control can configure 'network slice usage control function support' using the Subscription Permanent Identifier (SUPI) of the Universal Subscriber Identity Module (USIM) or Open Mobile Alliance Device Management (OMA-DM). According to one embodiment, 'network slice usage control function support' may be configured on the terminal by pre-configuration, or the network may configure 'network slice usage control function support' on the terminal according to carrier policies or URSP rules (UE Route Selection Policy rules). According to one embodiment, configuration information for configuring 'network slice usage control function support' on the terminal may be provided to the terminal through a registration acceptance message or a configuration update command message. The terminal may configure 'network slice usage control function support' in response to the registration acceptance message or the configuration update command message, and respond by sending a registration request message or a configuration update completion message to the network.

[0253] In operation 330, the terminal transmits a registration request message to the network that includes on-demand S-NSSAI information as requested NSSAI information.

[0254] The network receives a registration request message sent by the terminal requesting the use of on-demand S-NSSAI and acknowledges the terminal's request for on-demand S-NSSAI use. In response to the terminal's request for on-demand S-NSSAI use, the network sends a registration acceptance message in operation 350 that permits the use of on-demand S-NSSAI. The terminal receives the registration acceptance message sent by the network and acknowledges the permission to use on-demand S-NSSAI.

[0255] Even while performing the aforementioned operation, the slice registration cancellation inactive timer values ​​provided in the terminal and the network, respectively, continue to operate.

[0256] The terminal may make a PDU session establishment request or a PDU session modification request associated with the on-demand S-NSSAI to establish a PDU session for specific data transmission. Subsequently, after receiving a PDU session establishment acceptance or a PDU session modification command associated with the on-demand S-NSSAI from the network, data transmission and reception are performed through the PDU session associated with the on-demand S-NSSAI.

[0257] According to one embodiment, a terminal may establish an always-on PDU session related to an on-demand S-NSSAI for a connection such as an ultra-low latency service. To establish an always-on PDU session related to an on-demand S-NSSAI, the application layer of the terminal transmits a request to establish an always-on PDU session or a request to modify a PDU session to the non-access stratum (NAS) layer of the terminal, and the NAS layer of the terminal, in operation 340, transmits a PDU session establishment request message or a PDU session modification request message containing information on the always-on PDU session request to the network to establish an always-on PDU session. At this time, the terminal may additionally include a slice deregistration inactivity timer overriding indication / information in the PDU session establishment request message or the PDU session modification request message and transmit it to the network.

[0258] When the network receives from the terminal a PDU session formation request message or a PDU session modification request message containing information on requesting an on-demand S-NSSAI related always-on PDU session and / or instructions / information on applying priority to the slice unregister inactive timer, the network locally stops the on-demand S-NSSAI related slice unregister inactive timer operation in operation 345 to allow the establishment of the on-demand S-NSSAI related always-on PDU session requested by the terminal. At this time, the network may store the slice unregister inactive timer expiration value at the time the on-demand S-NSSAI related slice unregister inactive timer operation was stopped. Alternatively, the network may completely reset the on-demand S-NSSAI related slice unregister inactive timer.

[0259] Subsequently, to allow the establishment of an always-on PDU session related to the on-demand S-NSSAI, the network transmits a PDU session formation acceptance message or a PDU session modification command message to the terminal, which includes information on an always-on PDU session indication, in operation 350. At this time, the network may additionally include a slice unregister inactive timer priority application support indication / information in the PDU session formation acceptance message or the PDU session modification command message and transmit it to the terminal. The slice unregister inactive timer priority application support indication / information may indicate that the always-on PDU session related to the on-demand S-NSSAI being established or modified supports the slice unregister inactive timer priority application support indication / information. Based on the slice unregister inactive timer priority application support indication / information, the terminal may expect that the operation of the slice unregister inactive timer associated with the always-on PDU session related to the on-demand S-NSSAI will be stopped or the value of the timer will be reset.

[0260] After receiving from the network a PDU session formation acceptance message or a PDU session modification command message containing information on an always-on PDU session instruction and / or instructions / information on supporting the priority application of a slice unregister inactive timer, the terminal locally stops the active slice unregister inactive timer in operation 355. Subsequently, the terminal can perform data transmission and / or reception (for ultra-low latency related service connections) through the always-on PDU session associated with the configured or modified on-demand S-NSSAI.

[0261] Afterwards, either action a or action b below may be additionally performed.

[0262] (Operation a) After the terminal stops the operation of the slice unregister inactive timer, the terminal may remove the on-demand S-NSSAI from the allowed NSSAI. The network may also stop the operation of the slice unregister inactive timer, remove the on-demand S-NSSAI, and provide the terminal with updated allowed NSSAI information via a configuration update command message so that the terminal may update the allowed NSSAI information.

[0263] or,

[0264] (Operation b) After stopping the operation of the slice unregister inactive timer, the terminal may not remove the on-demand S-NSSAI from the allowed NSSAI. The network may also not remove the on-demand S-NSSAI from the allowed NSSAI after stopping the operation of the slice unregister inactive timer. Subsequently, after all data transmission and reception based on the always-on PDU session have ended and the always-on PDU session has been released, the terminal and the network may resume the operation of the slice unregister inactive timer that was stopped. At this time, the slice unregister inactive timer may restart from the value at which it was stopped in Operation 345 or Operation 355, or it may be reset and restart from the beginning. Then, when the slice unregister inactive timer expires, the operation to remove the aforementioned on-demand S-NSSAI from the allowed NSSAI may be performed by the terminal and the network.

[0265] Next, as a solution to the problem according to the current 3GPP technical specifications, a method may be considered in which the always-on PDU session associated with the on-demand S-NSSAI is configured / defined so that it is impossible to configure.

[0266] FIG. 4 is a flowchart illustrating the interoperability between a terminal and a network according to a second embodiment that makes it impossible to set up an always-on PDU session associated with the on-demand S-NSSAI presented in the present disclosure.

[0267] Referring to FIG. 4, the mutual interaction operations between the terminal and the network from operations 310 to 335, up to allowing the use of the initial on-demand S-NSSAI in the second embodiment, are the same as those in the first embodiment. Therefore, a description thereof is omitted.

[0268] The terminal may intend to perform an always-on PDU session setup related to on-demand S-NSSAI for connections such as ultra-low latency services. To this end, the terminal's application layer transmits a request for an always-on PDU session setup to the terminal's NAS layer.

[0269] In operation 410, the terminal NAS recognizes that since the slice unregistration inactive timer is currently running, it should not perform the on-demand S-NSSAI related PDU session formation procedure or PDU session modification procedure. Therefore, the terminal NAS recognizes that it cannot transmit the PDU session formation request message or the PDU session modification request message to the network, and accordingly, the terminal NAS does not transmit the PDU session formation request message or the PDU session modification request message to the network. As a result, the terminal NAS can reject the always-on PDU session formation requested by the terminal's application layer, and in response to the request from the terminal's application layer, the terminal NAS informs the application layer that the transmission of the PDU session formation request message or the PDU session modification request message has failed. Subsequently, in operation 420, the application layer or the terminal NAS layer can interact with the network to perform the always-on PDU session formation based on allowed NSSAI information unrelated to the on-demand S-NSSAI.

[0270] Afterwards, when the slice unregister inactive timer operation expires in operation 430, the terminal can terminate the slice unregister inactive timer operation and remove the on-demand S-NSSAI from the allowed NSSAI.

[0271] The network also, in operation 440, stops the slice deregistration inactive timer operation, removes the on-demand S-NSSAI from the allowed NSSAI, and in operation 450, provides the updated allowed NSSAI information to the terminal via a configuration update command message. In operation 460, the terminal receives the updated allowed NSSAI information from the network and can update the allowed NSSAI information. According to one embodiment, the terminal can additionally perform operation 430 because it can update the allowed NSSAI information according to operation 460.

[0272] Next, as a solution of the present disclosure to address the problems according to current 3GPP technical specifications, a method may be considered in which the network is configured / defined to reject always-on PDU session settings associated with on-demand S-NSSAI.

[0273] FIG. 5 is a flowchart illustrating the interaction operation between a terminal and a network according to a third embodiment in which the network rejects the setting of an always-on PDU session associated with the on-demand S-NSSAI presented in the present disclosure.

[0274] Referring to FIG. 5, the mutual interaction operations between the terminal and the network from operations 310 to 335, up to allowing the use of the initial on-demand S-NSSAI in the third embodiment, are the same as those in the first embodiment. Therefore, a description thereof is omitted.

[0275] The terminal can perform an always-on PDU session setup related to on-demand S-NSSAI for a connection such as an ultra-low latency service. To perform an always-on PDU session setup related to on-demand S-NSSAI, the application layer of the terminal transmits an always-on PDU session setup request or a modification request to the terminal's NAS (non-access stratum) layer. In operation 510, the terminal's NAS transmits a PDU session setup request message or a PDU session modification request message containing information about the always-on PDU session request to the network for the always-on PDU session setup.

[0276] In operation 520, if the network receives a PDU session establishment request message or a PDU session modification request message containing information regarding an always-on PDU session related to an on-demand S-NSSAI, and the slice deregistration inactivity timer is running at that time, the network may reject the always-on PDU session establishment related to an on-demand S-NSSAI requested by the terminal. To reject the always-on PDU session establishment related to an on-demand S-NSSAI requested by the terminal, the network sends a PDU session establishment reject message or a PDU session modification reject message to the terminal containing a cause value #xy in operation 530. Here, the cause value #xy may indicate that the always-on PDU session is not supported due to the slice deregistration inactivity timer running. In this case, the network may additionally include a back-off timer Tabcd in the PDU session formation rejection message or the PDU session modification rejection message.

[0277] Upon receiving a PDU session formation rejection message or a PDU session modification rejection message containing reason value #xy from the network, the terminal NAS informs the application layer that the on-demand S-NSSAI related always-on session setup has failed. Additionally, the terminal NAS does not retry the on-demand S-NSSAI related always-on PDU session setup. That is, the terminal does not retransmit to the network a PDU session formation request message or a PDU session modification request message containing on-demand S-NSSAI related always-on PDU session request information. Furthermore, according to one embodiment, the terminal can perform the always-on PDU session setup in operation 540 in interaction with the network, identical to operation 420 of FIG. 4, based on allowed NSSAI information unrelated to the on-demand S-NSSAI.

[0278] If the PDU session formation rejection message or PDU session modification rejection message received by the terminal, as in operation 531, contains a back-off timer Tabcd, the terminal activates the back-off timer Tabcd in operation 550. When the back-off timer Tabcd expires, the terminal may, in operation 560, retransmit a PDU session formation request message or a PDU session modification request message containing information on an always-on PDU session request related to the on-demand S-NSSAI to the network. That is, the terminal may retry the on-demand S-NSSAI related always-on PDU session formation.

[0279] If the terminal fails to set up an always-on PDU session related to the on-demand S-NSSAI after a preset number of retries, it determines that it has failed, and the application layer or the NAS layer of the terminal can perform the always-on PDU session setup based on allowed NSSAI information unrelated to the on-demand S-NSSAI, just like in operation 540.

[0280] When the slice cancellation inactivity timer operation expires, the terminal may stop the slice cancellation inactivity timer operation and remove the on-demand S-NSSAI from the allowed NSSAI. The network also removes the on-demand S-NSSAI from the allowed NSSAI after stopping the slice cancellation inactivity timer operation. Then, the network may provide the updated allowed NSSAI information to the terminal via a configuration update command message so that the terminal updates the allowed NSSAI information. The above-described operation may be identical to operations 430 to 460 of FIG. 4.

[0281] Additionally, at least one of the following methods may be operated in combination: a method for stopping the slice cancellation disable timer related to the aforementioned on-demand S-NSSAI, a method for setting / defining that an always-on PDU session setting related to the on-demand S-NSSAI is impossible at the terminal, and a method for setting / defining that an always-on PDU session setting related to the on-demand S-NSSAI is rejected by the network.

[0282] Additionally, the terminal may receive a higher-level signal from the network directing an action based on any one of the following: a method for stopping a slice unregistration disable timer associated with the aforementioned on-demand S-NSSAI; a method for setting / defining that an always-on PDU session setup associated with the on-demand S-NSSAI is impossible at the terminal; or a method for setting / defining that an always-on PDU session setup associated with the on-demand S-NSSAI is rejected by the network.

[0283] Additionally, if the PDU session formation rejection message or PDU session modification rejection message received by the terminal includes a back-off timer Tabcd, the back-off timer Tabcd expires, and if the always-on PDU session setting is successful following a retry of the always-on PDU session setting, the slice unregistration inactive timer operation may also be set to stop so that the operations in operations 345 and 355 of FIG. 3 are performed.

[0284] Additionally, if the PDU session formation rejection message or PDU session modification rejection message received by the terminal includes a back-off timer Tabcd, and after the back-off timer Tabcd expires, a retry of the always-on PDU session setup fails, the slice unregistration inactive timer operation may be maintained.

[0285] According to the present disclosure, when supporting network slice usage control between a terminal and a network, and performing a PDU session formation procedure or a PDU session modification procedure related to the terminal's always-on PDU session in accordance with the operation of the on-demand S-NSSAI and the slice cancellation inactivity timer, the problem of ultra-low latency service connection issues, signaling overhead, and resource waste caused by inefficient operation can be resolved. When the slice cancellation inactivity timer related to the on-demand S-NSSAI is in operation and the setting of an always-on PDU session is requested, an efficient processing method can be performed. Accordingly, unnecessary signaling overhead is reduced, thereby minimizing battery and resource waste for the terminal and the network and enabling the continuous provision of ultra-low latency services.

[0286] FIG. 6 is a flowchart illustrating an example of an always-on PDU session setup operation related to an on-demand S-NSSAI performed by a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0287] Referring to FIG. 6, in operation 610, the terminal can transmit a first message to request on-demand S-NSSAI (Single Network Slice Selection Assistance Information) to the network.

[0288] In operation 620, the terminal may receive a second message from the network containing an on-demand S-NSSAI. At this time, the second message may include an expiration value for driving a slice unregister inactive timer.

[0289] In operation 630, the terminal may send a registration request message to the network to request the use of an on-demand S-NSSAI. Here, the registration request message may include requested NSSAI information containing an on-demand S-NSSAI.

[0290] In operation 640, the terminal may receive a registration acceptance message from the network that permits the use of on-demand S-NSSAI.

[0291] In operation 650, the terminal may transmit a third message to the network for an always-on PDU session setup associated with an on-demand S-NSSAI. The operation of the terminal may vary according to each of the embodiments described above.

[0292] In the case of the first embodiment, the terminal may transmit a PDU session formation request message or a PDU session modification request message to the network, which includes PDU session request information that is always on and slice cancellation inactivity timer priority application information.

[0293] In the case of the second embodiment, the terminal may transmit to the network a PDU session formation request message or a PDU session modification request message containing PDU session request information that is always turned on, based on allowed NSSAI information unrelated to the on-demand S-NSSAI.

[0294] In the case of the third embodiment, the terminal may transmit a PDU session formation request message or a PDU session modification request message to the network, which includes PDU session request information that is always turned on.

[0295] In operation 660, the terminal may receive a fourth message from the network rejecting or accepting an always-on PDU session setup. The operation of the terminal may vary according to each of the embodiments described above.

[0296] In the case of the first embodiment, the terminal receives a PDU session formation acceptance message or a PDU session modification command message from the network, which includes PDU session instruction information that is always on and instruction / information for supporting priority application of the slice unregister inactive timer, and can stop the slice unregister inactive timer operation.

[0297] In the case of the second embodiment, the terminal may receive a PDU session formation acceptance message or a PDU session modification command message containing PDU session instruction information that is always turned on based on allowed NSSAI information unrelated to the on-demand S-NSSAI.

[0298] In the case of the third embodiment, the terminal may receive a PDU session formation rejection message or a PDU session modification rejection message from the network, which includes a rejection reason value. In this case, the terminal may interact with the network to perform an always-on PDU session setup based on allowed NSSAI information unrelated to the on-demand S-NSSAI.

[0299] In the case of another third embodiment, the terminal may receive from the network a PDU session formation rejection message or a PDU session modification rejection message including a rejection reason value and a back-off timer. In this case, the terminal may retry the always-on PDU session formation associated with the on-demand S-NSSAI after the back-off timer has expired.

[0300] FIG. 7 is a flowchart illustrating an example of an always-on PDU session setup operation associated with an on-demand S-NSSAI performed by a network in a wireless communication system according to one embodiment of the present disclosure.

[0301] Referring to FIG. 7, the network can receive a first message for requesting on-demand S-NSSAI (Single Network Slice Selection Assistance Information) transmitted by the terminal in operation 710.

[0302] In operation 720, the network may transmit a second message containing an on-demand S-NSSAI to the terminal. At this time, the second message may include an expiration value for driving a slice unregister inactive timer.

[0303] In operation 730, the network may receive a registration request message from a terminal to request the use of an on-demand S-NSSAI. Here, the registration request message may include requested NSSAI information containing an on-demand S-NSSAI.

[0304] In operation 740, the network may send a registration acceptance message to the terminal to allow the use of on-demand S-NSSAI.

[0305] In operation 750, the network may receive a third message from the terminal for an always-on PDU session setup related to an on-demand S-NSSAI. The message transmitted by the terminal may vary according to each of the embodiments described above.

[0306] In the case of the first embodiment, the message transmitted by the terminal may be a PDU session formation request message or a PDU session modification request message including always-on PDU session request information and slice unregistration inactive timer priority application information.

[0307] In the case of the second embodiment, the message transmitted by the terminal may be a PDU session formation request message or a PDU session modification request message containing PDU session request information that is always turned on based on allowed NSSAI information unrelated to the on-demand S-NSSAI.

[0308] In the case of the third embodiment, the message transmitted by the terminal may be a PDU session formation request message or a PDU session modification request message containing PDU session request information that is always turned on.

[0309] In operation 760, the network may transmit a fourth message to the terminal to reject or accept a PDU session setup that is always turned on. At this time, the operation of the network may vary according to each of the embodiments described above.

[0310] In the case of the first embodiment, the network may, upon receiving the third message, approve the establishment of an always-on PDU session associated with the on-demand S-NSSAI and transmit a PDU session formation acceptance message or a PDU session modification command message including always-on PDU session instruction information and instruction / information for supporting priority application of the slice unregister inactive timer. Additionally, the network may stop the slice unregister inactive timer operation.

[0311] In the case of the second embodiment, the network may transmit a PDU session formation acceptance message or a PDU session modification command message containing PDU session instruction information that is always turned on, based on allowed NSSAI information unrelated to the on-demand S-NSSAI.

[0312] In the case of the third embodiment, the network may transmit a PDU session formation rejection message or a PDU session modification rejection message containing a rejection reason value.

[0313] In the case of another third embodiment, the network may receive a PDU session formation rejection message or a PDU session modification rejection message including a rejection reason value and a back-off timer.

[0314] FIG. 8 is a drawing illustrating the structure of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0315] Referring to FIG. 8, the terminal may include a transceiver comprising a terminal receiver (800) and a terminal transmitter (810), a memory (not shown), and a terminal processing unit (805, or a terminal control unit or processor). Depending on the communication method of the terminal described above, the transceiver (800, 810), memory, and terminal processing unit (805) of the terminal may operate. However, the components of the terminal are not limited to the examples described above. For example, the terminal may include more components or fewer components than the components described above. Furthermore, the transceiver, memory, and processor may be implemented in the form of a single chip.

[0316] The transceiver (800, 810) can transmit and receive signals with a base station ((R)AN). Here, the signal may include control information and data. To this end, the transceiver (800, 810) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver, and the components of the transceiver are not limited to an RF transmitter and an RF receiver.

[0317] Additionally, the transceiver (800, 810) can receive a signal through a wireless channel and output it to a processor (805), and transmit the signal output from the processor (805) through a wireless channel.

[0318] Memory can store programs and data necessary for the operation of the terminal. Additionally, memory can store control information or data included in signals transmitted and received by the terminal. Memory may be composed of storage media or combinations of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, there may be multiple memories.

[0319] Additionally, the processor (805) can control a series of processes to enable the terminal to operate according to the above-described embodiment. For example, the processor (805) can control the components of the terminal to receive a DCI composed of two layers and receive multiple PDSCHs simultaneously. There may be multiple processors (805), and the processor (805) can perform the control operation of the terminal components by executing a program stored in memory.

[0320] FIG. 9 is a drawing illustrating the structure of a base station in a wireless communication system according to one embodiment of the present disclosure.

[0321] Referring to FIG. 9, a base station ((R)AN) may include a transceiver unit comprising a base station receiver (930) and a base station transmitter (910), a memory (not shown), and a base station processing unit (905, or a base station control unit or processor). Depending on the communication method of the base station described above, the transceiver unit (900, 910), memory, and base station processing unit (905) of the base station may operate. However, the components of the base station are not limited to the examples described above. For example, the base station may include more components or fewer components than the components described above. Furthermore, the transceiver unit, memory, and processor may be implemented in the form of a single chip.

[0322] The transceiver (900, 910) can transmit and receive signals with a terminal. Here, the signal may include control information and data. To this end, the transceiver (900, 910) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver, and the components of the transceiver are not limited to an RF transmitter and an RF receiver.

[0323] Additionally, the transceiver (900, 910) can receive a signal through a wireless channel and output it to a processor (905), and transmit the signal output from the processor (905) through a wireless channel.

[0324] Memory can store programs and data necessary for the operation of the base station. Additionally, memory can store control information or data included in signals transmitted and received by the base station. Memory can be composed of storage media or combinations of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, there may be multiple memories.

[0325] The processor (905) can control a series of processes to enable the base station to operate according to the embodiments of the present disclosure described above. For example, the processor (905) can control each component of the base station to configure two layers of DCIs containing allocation information for a plurality of PDSCHs and to transmit them. There may be multiple processors (905), and the processor (905) can perform the control operation of the base station components by executing a program stored in memory.

[0326] FIG. 10 is a drawing illustrating the structure of a network in a wireless communication system according to one embodiment of the present disclosure.

[0327] In the previous description and FIG. 10, the network refers to a device equipped in the 5G core network (5GC), which may be an AMF, SMF, PCF, AUSF, or UDM.

[0328] Referring to FIG. 10, the network may include a transceiver comprising a network receiver (1000) and a network transmitter (1010), a memory (not shown), and a network processing unit (1005, or a network control unit or processor). Depending on the communication method of the network described above, the transceiver (1000, 1010), the memory, and the network processing unit (1005) of the network may operate. However, the components of the network are not limited to the examples described above. For example, the network may include more components or fewer components than the components described above. Furthermore, the transceiver, the memory, and the processor may be implemented in the form of a single chip.

[0329] The transceiver (1000, 1010) can transmit and receive signals with a base station. Here, the signal may include control information and data. According to one embodiment, the transceiver (1000, 1010) can transmit a signal to a base station or receive a signal from a base station via a wired IP network. However, this is merely one embodiment of the transceiver, and the components of the transceiver are not limited thereto.

[0330] Additionally, the transmitting and receiving unit (1000, 1010) can output the received signal to the processor (1005) and transmit the signal output from the processor (1005) through a wired IP network.

[0331] Memory can store programs and data necessary for the operation of a network. Additionally, memory can store control information or data included in signals transmitted and received by the network. Memory can be composed of storage media or combinations of storage media, such as ROM, RAM, hard disks, CD-ROMs, and DVDs. Additionally, there may be multiple memory units.

[0332] Additionally, the processor (1005) can control a series of processes to enable the network to operate according to the above-described embodiment. There may be multiple processors (1005), and the processor (1005) can perform control operations on the components of the network by executing a program stored in memory.

[0333] The methods according to the claims of the present disclosure or the embodiments described in the disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0334] When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or description of the present disclosure.

[0335] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disc storage devices, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0336] Additionally, the program may be stored on an attachable storage device that can be accessed via a communication network such as the Internet, Intranet, LAN (local area network), WAN (wide area network), or SAN (storage area network), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0337] In the specific embodiments of the present disclosure described above, the components included in the disclosure are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed of a singular form, and even if a component is expressed in the singular form, it may be composed of a plural form.

[0338] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

Claims

1. A method performed by a terminal in a wireless communication system, wherein the method comprises: A step of transmitting a first message to request on-demand S-NSSAI (Single Network Slice Selection Assistance Information) to a network; A step of receiving a second message from the above network, the message including an expiration value for driving the on-demand S-NSSAI and the slice deregistration inactivity timer; A step of transmitting a registration request message containing requested NSSAI information including the on-demand S-NSSAI to the above network to request the use of the on-demand S-NSSAI; A step of receiving a registration acceptance message from the above network that permits the use of the on-demand S-NSSAI; The step of transmitting a third message to the above network, including a request for an always-on PDU session associated with the on-demand S-NSSAI and a request for priority application of a slice unregistration inactive timer; and A method comprising the step of receiving a fourth message containing always-on PDU session instruction information indicating always-on PDU session acknowledgment associated with the on-demand S-NSSAI from the above network.

2. In Paragraph 1, A step of operating the registration cancellation inactive timer based on the above expiration value; and A method further comprising the step of stopping the operation of the registration cancellation inactive timer based on receiving the fourth message.

3. In Paragraph 2, A step of performing data transmission and reception based on the above always-on PDU session; A step of releasing the always-on PDU session after both data transmission and reception have ended; A step of restarting the operation of the unregistered inactive timer in response to the release of the always-on PDU session; A method further comprising the step of removing the on-demand S-NSSAI from the allowed S-NSSAI list when the above-mentioned registration cancellation inactivity timer expires.

4. In Paragraph 2, Step of removing the on-demand S-NSSAI from the allowed S-NSSAI list after stopping the operation of the above-mentioned registration cancellation inactive timer; and A method further comprising the step of performing data transmission and reception based on the above always-on PDU session.

5. In Paragraph 1, The first message above is a Registration Request message or a Configuration Update Complete message, and The second message above is a Registration Accept message or a Configuration Update Command message, and The third message above is a PDU Session Establishment Request message or a PDU Session Modification Request message A method in which the fourth message is a PDU Session Establishment Accept message or a PDU Session Modification Command message.

6. In a method performed by a network in a wireless communication system, the method comprises: A step of receiving a first message from a terminal to request on-demand S-NSSAI (Single Network Slice Selection Assistance Information); A step of transmitting to the terminal a second message containing an expiration value for driving the on-demand S-NSSAI and slice deregistration inactivity timer; A step of receiving a registration request message from the terminal containing requested NSSAI information including the on-demand S-NSSAI to request the use of the on-demand S-NSSAI; A step of transmitting a registration acceptance message to the terminal that permits the use of the on-demand S-NSSAI; Receiving a third message from the terminal, including a request for an always-on PDU session associated with the on-demand S-NSSAI and a request for priority application of a slice unregistration inactive timer; and A method comprising the step of transmitting to the terminal a fourth message containing always-on PDU session instruction information indicating always-on PDU session acknowledgment associated with the on-demand S-NSSAI.

7. In Paragraph 6, A step of operating the registration cancellation inactive timer based on receiving the first message; and A method further comprising the step of stopping the operation of the registration cancellation inactive timer based on receiving the third message.

8. In Paragraph 7, A step of releasing the always-on PDU session when all data transmission and reception based on the always-on PDU session are terminated; A step of restarting the operation of the unregistered inactive timer based on the release of the always-on PDU session; When the above registration cancellation inactivity timer expires, the step of removing the above on-demand S-NSSAI from the list of allowed S-NSSAIs; A method further comprising the step of transmitting the updated allowed S-NSSAI list to the terminal.

9. In Paragraph 7, A method further comprising the step of removing the on-demand S-NSSAI from the allowed S-NSSAI list after stopping the operation of the above-mentioned registration cancellation inactive timer.

10. In Paragraph 6, The first message above is a Registration Request message or a Configuration Update Complete message, and The second message above is a registration acceptance message or a configuration update command message, and The third message above is a PDU Session Establishment Request message or a PDU Session Modification Request message A method in which the fourth message is a PDU Session Establishment Accept message or a PDU Session Modification Command message.

11. A method performed by a terminal in a wireless communication system, wherein the method comprises: A step of transmitting a first message to request on-demand S-NSSAI (Single Network Slice Selection Assistance Information) to a network; A step of receiving a second message from the above network, the message including an expiration value for driving the on-demand S-NSSAI and the slice deregistration inactivity timer; A step of operating the registration cancellation inactive timer based on the above expiration value; A step of transmitting a registration request message containing requested NSSAI information including the on-demand S-NSSAI to the above network to request the use of the on-demand S-NSSAI; A step of receiving a registration acceptance message from the above network that permits the use of the on-demand S-NSSAI; A method comprising the step of establishing an always-on PDU session based on allowed NSSAI information unrelated to the on-demand S-NSSAI, based on the operation of the above-mentioned registration cancellation inactive timer.

12. In Paragraph 11, A method further comprising the step of removing the on-demand S-NSSAI from the allowed S-NSSAI list when the above-mentioned registration cancellation inactivity timer expires.

13. A method performed by a network in a wireless communication system, wherein the method comprises: A step of receiving a first message from a terminal to request on-demand S-NSSAI (Single Network Slice Selection Assistance Information); A step of transmitting to the terminal a second message containing an expiration value for driving the on-demand S-NSSAI and slice deregistration inactivity timer; A step of operating the registration cancellation inactive timer based on the above expiration value; A step of receiving a registration request message from the terminal containing requested NSSAI information including the on-demand S-NSSAI to request the use of the on-demand S-NSSAI; A step of transmitting a registration acceptance message to the terminal that permits the use of the on-demand S-NSSAI; A method comprising the step of establishing an always-on PDU session based on allowed NSSAI information unrelated to the on-demand S-NSSAI, based on the operation of the registration cancellation inactive timer in conjunction with the terminal.

14. In Paragraph 13, When the above-mentioned registration cancellation inactivity timer expires, the step of removing the above-mentioned on-demand S-NSSAI from the list of allowed S-NSSAIs; and A method further comprising the step of transmitting the updated allowed S-NSSAI list to the terminal.

15. A method performed by a terminal in a wireless communication system, wherein the method comprises: A step of transmitting a first message to request on-demand S-NSSAI (Single Network Slice Selection Assistance Information) to a network; A step of receiving a second message from the above network, the message including an expiration value for driving the on-demand S-NSSAI and the slice deregistration inactivity timer; A step of transmitting a registration request message containing requested NSSAI information including the on-demand S-NSSAI to the above network to request the use of the on-demand S-NSSAI; A step of receiving a registration acceptance message from the above network that permits the use of the on-demand S-NSSAI; The step of transmitting a third message to the above network, comprising a request for an always-on PDU session associated with the on-demand S-NSSAI; and A method comprising the step of receiving a fourth message rejecting a request for an always-on PDU session associated with the on-demand S-NSSAI from the network.

16. In Paragraph 15, It further includes the step of operating the registration cancellation inactive timer based on the above expiration value, A method in which the above fourth message includes a rejection reason value indicating that the slice unregister inactive timer is in operation and cannot support a PDU session that is always on.

17. In Paragraph 16, The above fourth message further includes a back-off timer, and A method further comprising the step of, after the back-off timer expires, retransmitting a third message to the network containing a request for an always-on PDU session associated with the on-demand S-NSSAI.

18. In Paragraph 16, A method further comprising the step of removing the on-demand S-NSSAI from the allowed S-NSSAI list when the above-mentioned registration cancellation inactivity timer expires.

19. In Paragraph 15, The first message above is a Registration Request message or a Configuration Update Complete message, and The second message above is a registration acceptance message or a configuration update command message, and The third message above is a PDU Session Establishment Request message or a PDU Session Modification Request message A method in which the above-mentioned fourth message is a PDU Session Establishment Reject message or a PDU Session Modification Reject message.

20. A method performed by a network in a wireless communication system, wherein the method is, A step of receiving a first message from a terminal to request on-demand S-NSSAI (Single Network Slice Selection Assistance Information); A step of transmitting to the terminal a second message containing an expiration value for driving the on-demand S-NSSAI and slice deregistration inactivity timer; A step of receiving a registration request message from the terminal containing requested NSSAI information including the on-demand S-NSSAI to request the use of the on-demand S-NSSAI; A step of transmitting a registration acceptance message to the terminal that permits the use of the on-demand S-NSSAI; Receiving a third message from the terminal, comprising a request for an always-on PDU session associated with the on-demand S-NSSAI; and A method comprising the step of transmitting a fourth message to the terminal that rejects a request for an always-on PDU session associated with the on-demand S-NSSAI.

21. In Paragraph 20, It further includes the step of operating the registration cancellation inactive timer based on the above expiration value, A method in which the above fourth message includes a rejection reason value indicating that the slice unregister inactive timer is in operation and cannot support a PDU session that is always on.

22. In Article 20, When the above registration cancellation inactivity timer expires, the step of removing the above on-demand S-NSSAI from the list of allowed S-NSSAIs; A method further comprising the step of transmitting the allowed S-NSSAI list updated to the terminal.

23. In Paragraph 20, The first message above is a Registration Request message or a Configuration Update Complete message, and The second message above is a registration acceptance message or a configuration update command message, and The third message above is a PDU Session Establishment Request message or a PDU Session Modification Request message A method in which the above-mentioned fourth message is a PDU Session Establishment Reject message or a PDU Session Modification Reject message.

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