JP7624933B2 - UE, control device, and communication control method - Google Patents

Description

This application relates to a UE, a control device, and a communication control method. This application claims the benefit of priority to Japanese Patent Application No. 2019-238128, filed on December 27, 2019, the entire contents of which are incorporated herein by reference.

3GPP (3rd Generation Partnership Project), which has been working on standardization of mobile communication systems in recent years, is currently studying SAE (System Architecture Evolution), the system architecture for LTE (Long Term Evolution).

In recent years, 3GPP has also been studying next-generation communication technologies and system architectures for the next-generation mobile communication system, 5G (5th Generation) mobile communication system, and in particular has been working on the specification of 5GS (5G System) as a system to realize the 5G mobile communication system (see Non-Patent Documents 1 and 2). In 5GS, technical issues for connecting a wide variety of terminals to a cellular network are being extracted and solutions are being specified.

3GPP TS 23.501 V16.3.0 (2019-12); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System Architecture for the 5G System; Stage 2 (Release 16) 3GPP TS 23.502 V16.3.0 (2019-12); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Procedures for the 5G System; Stage 2 (Release 16) 3GPP TS 24.501 V16.3.0 (2019-12); 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3 (Release 16) 3GPP TR 23.700-40 V0.2.0 (2019-11); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Study on Enhancement of Network Slicing Phase 2 (Release 17)

In 5GS (5G System), a new core network, 5GCN (5G Core Network), is being considered to provide a wide variety of services.

Furthermore, 5G defines network slices, which are logical networks that provide specific network functions or specific network characteristics for a specific service type or a specific group. For example, a network slice may be a logical network provided for a terminal with low latency capabilities, or a logical network provided for a sensor terminal used in the Internet of Things (IoT).

3GPP is currently studying Enhancement of Network Slicing (eNS) to consider further functions related to network slicing. Furthermore, as part of Phase 2 of eNS, 3GPP is considering adding a function to manage the number of UEs permitted per slice. However, it is not clear how to achieve this in order to meet the above requirements.

The present invention has been made in consideration of the above circumstances, and aims to provide a method for realizing functions for eNS in 5GS.

The UE (User Equipment; terminal device) of the present invention comprises a transceiver unit that receives first information and second information from a control device during a registration procedure, and a control unit that, when NSSAI (Network Slice Selection Assistance information) is not provided to the control device, associates no NSSAI with a back-off timer based on the reception of the first information and the second information, and starts the back-off timer with a value indicated by the second information, wherein the first information is a reason value indicating that connection to a slice is restricted, the second information is information indicating a value of the back-off timer, and the UE is not permitted to send a registration request message that does not include an NSSAI while the back-off timer is running.

The control device of the present invention comprises a transceiver unit that receives a registration request message not including NSSAI (Network Slice Selection Assistance information) from a UE (User Equipment; terminal device) during a registration procedure and transmits a control message to the UE, and a control unit that includes first information and second information in the control message when a default slice is congested, and the control device instructs the UE to start a back-off timer by transmitting the control message, the first information being a reason value indicating that connection to the slice is restricted, and the second information being information indicating the value of the back-off timer, and while the back-off timer is running, transmission of a registration request message not including an NSSAI from the UE is not permitted.

The communication control method for a UE (User Equipment; terminal device) of the present invention includes the steps of receiving first information and second information from a control device, and, when NSSAI (Network Slice Selection Assistance information) is not provided to the control device, associating no NSSAI with a back-off timer based on the reception of the first information and the second information, and starting the back-off timer with a value indicated by the second information, wherein the first information is a reason value indicating that connection to a slice is restricted, the second information is information indicating a value of a back-off timer, and the UE is not permitted to transmit a registration request message that does not include an NSSAI while the back-off timer is running.

The communication control method of the control device of the present invention includes the steps of receiving a registration request message not including NSSAI (Network Slice Selection Assistance information) from a UE (User Equipment; terminal device), including first information and second information in a control message when a default slice is congested, and transmitting the control message to the UE, wherein the control device instructs the UE to start a back-off timer by transmitting the control message, the first information being a reason value indicating that connection to the slice is restricted, and the second information being information indicating a value of the back-off timer, and while the back-off timer is running, transmission of a registration request message not including NSSAI from the UE is not permitted.

According to one aspect of the present invention, in 5GS, support for eNS becomes possible and the number of UEs allowed per slice can be managed.

1 is a diagram illustrating an overview of a mobile communication system (EPS/5GS). A diagram explaining the detailed configuration of a mobile communication system (EPS/5GS). A diagram explaining the device configuration of a UE. A diagram explaining the configuration of an access network device (gNB) in 5GS. A diagram explaining the configuration of core network devices (AMF/SMF/UPF) in 5GS. FIG. 1 is a diagram illustrating a registration procedure.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. In this embodiment, as an example, an embodiment of a mobile communication system to which the present invention is applied will be described.

[1. System Overview]
First, FIG. 1 is a diagram for explaining an outline of a mobile communication system 1 used in each embodiment, and FIG. 2 is a diagram for explaining a detailed configuration of the mobile communication system 1. As shown in FIG.

Figure 1 shows that the mobile communication system 1 is composed of UE #A10, access network #A80, core network #A90, PDN (Packet Data Network) #A5, access network #B120, core network #B190, and DN (Data Network) #A6.

In the following, these devices and functions may be referred to without symbols, such as UE, access network #A, core network #A, PDN, access network #B, core network #B, DN, etc.

Figure 2 also shows devices and functions such as UE#A10, E-UTRAN80, MME40, SGW35, PGW-U30, PGW-C32, PCRF60, HSS50, 5G AN120, AMF140, UPF130, SMF132, PCF160, UDM150, N3IWF170, and interfaces that connect these devices and functions to each other.

In the following, these devices and functions may be referred to by abbreviated symbols, such as UE, E-UTRAN, MME, SGW, PGW-U, PGW-C, PCRF, HSS, 5G AN, AMF, UPF, SMF, PCF, UDM, N3IWF, etc.

The 4G system EPS (Evolved Packet System) is composed of an access network #A and a core network #A, but may further include a UE and/or a PDN. The 5G system 5GS (5G System) is composed of a UE, an access network #B, and a core network #B, but may further include a DN.

The UE is a device that can connect to a network service via 3GPP access (also referred to as a 3GPP access network, 3GPP AN) and/or non-3GPP access (also referred to as a non-3GPP access network, non-3GPP AN). The UE may be a terminal device capable of wireless communication such as a mobile phone or smartphone, and may be a terminal device that can connect to both EPS and 5GS. The UE may be equipped with a UICC (Universal Integrated Circuit Card) or an eUICC (Embedded UICC). The UE may be referred to as a user device or a terminal device.

Moreover, access network #A corresponds to an E-UTRAN (Evolved Universal Terrestrial Radio Access Network) and/or a wireless LAN access network. One or more eNBs (evolved Node B) 45 are arranged in the E-UTRAN. In the following, eNB 45 may be written with the symbol omitted, such as eNB. Furthermore, when there are multiple eNBs, the eNBs are connected to each other, for example, via an X2 interface. Furthermore, one or more access points are arranged in the wireless LAN access network.

Also, the access network #B corresponds to a 5G access network (5G AN). The 5G AN is composed of an NG-RAN (NG Radio Access Network) and/or a non-3GPP access network. One or more gNBs (NR NodeBs) 122 are arranged in the NG-RAN. In the following, the gNB 122 may be written with the symbol omitted, such as eNB. The gNB is a node that provides the NR (New Radio) user plane and control plane to the UE, and is a node that connects to the 5GCN via an NG interface (including an N2 interface or an N3 interface). In other words, the gNB is a base station device newly designed for 5GS, and has a different function from the base station device (eNB) used in the 4G system EPS. Also, when there are multiple gNBs, each gNB is connected to each other, for example, by an Xn interface.

The non-3GPP access network may be an untrusted non-3GPP access network or a trusted non-3GPP access network. Here, the untrusted non-3GPP access network may be a non-3GPP access network that does not perform security management within the access network, such as a public wireless LAN. On the other hand, the trusted non-3GPP access network may be an access network defined by 3GPP, and may include a TNAP (trusted non-3GPP access point) and a TNGF (trusted non-3GPP Gateway function).

In the following, E-UTRAN and NG-RAN may be referred to as 3GPP access. Furthermore, wireless LAN access networks and non-3GPP AN may be referred to as non-3GPP access. Furthermore, nodes placed in access network #B may be collectively referred to as NG-RAN nodes.

In addition, in the following, access network #A, and/or access network #B, and/or devices included in access network #A, and/or devices included in access network #B may be referred to as access networks or access network devices.

Core network #A corresponds to EPC (Evolved Packet Core). EPC includes, for example, MME (Mobility Management Entity), SGW (Serving Gateway), PGW (Packet Data Network Gateway)-U, PGW-C, PCRF (Policy and Charging Rules Function), HSS (Home Subscriber Server), etc.

Furthermore, core network #B corresponds to 5GCN (5G Core Network). In 5GCN, for example, AMF (Access and Mobility Management Function), UPF (User Plane Function), SMF (Session Management Function), PCF (Policy Control Function), UDM (Unified Data Management), etc. are arranged. Here, 5GCN may be expressed as 5GC.

In addition, in the following, core network #A and/or core network #B, devices included in core network #A, and/or devices included in core network #B may be referred to as core networks, or core network devices, or devices within a core network.

The core network (core network #A and/or core network #B) may be an IP mobile communications network operated by a mobile network operator (MNO) that connects an access network (access network #A and/or access network #B) to a PDN and/or DN, or it may be a core network for a mobile network operator that operates and manages mobile communications system 1, or it may be a core network for a virtual mobile communications operator such as an MVNO (Mobile Virtual Network Operator) or MVNE (Mobile Virtual Network Enabler) or a virtual mobile communications service provider.

Also, while FIG. 1 shows a case where the PDN and the DN are the same, they may be different. The PDN may be a DN (Data Network) that provides communication services to the UE. The DN may be configured as a packet data service network, or may be configured for each service. Furthermore, the PDN may include a connected communication terminal. Therefore, connecting to the PDN may be connecting to a communication terminal or a server device arranged in the PDN. Furthermore, transmitting and receiving user data to and from the PDN may be transmitting and receiving user data to and from a communication terminal or a server device arranged in the PDN. The PDN may be expressed as the DN, and the DN may be expressed as the PDN.

In addition, in the following, at least a portion of access network #A, core network #A, PDN, access network #B, core network #B, DN, and/or one or more devices included therein may be referred to as a network or network device. In other words, when a network and/or a network device transmits/receives a message and/or executes a procedure, it means that at least a portion of access network #A, core network #A, PDN, access network #B, core network #B, DN, and/or one or more devices included therein transmits/receives a message and/or executes a procedure.

The UE can also connect to an access network. The UE can also connect to a core network via the access network. The UE can also connect to a PDN or DN via the access network and the core network. That is, the UE can send and receive (communicate) user data with the PDN or DN. When sending and receiving user data, not only IP (Internet Protocol) communication but also non-IP communication may be used.

Here, IP communication refers to data communication using IP, and data is sent and received using IP packets. An IP packet is composed of an IP header and a payload section. The payload section may include data sent and received by devices and functions included in EPS and devices and functions included in 5GS. Non-IP communication refers to data communication that does not use IP, and data is sent and received in a format different from the structure of an IP packet. For example, non-IP communication may be data communication realized by sending and receiving application data without an IP header, or may be user data sent and received by a UE with another header such as a MAC header or an Ethernet (registered trademark) frame header.

In addition, access network #A, core network #A, access network #B, core network #B, PDN#A, and DN#A may be configured with devices not shown in Figure 2. For example, core network #A and/or core network #B may include an AUSF (Authentication Server Function) and an AAA (Authentication, authorization, and accounting) server (AAA-S).

Here, the AUSF is a core network device that has an authentication function for 3GPP access and non-3GPP access. Specifically, it is a network function unit that receives an authentication request for 3GPP access and/or non-3GPP access from the UE and executes the authentication procedure.

The AAA server is a device that has authentication, authorization and accounting functions and is connected to the AUSF directly or indirectly via another network device. The AAA server may be a network device within the core network. The AAA server may not be included in core network #A and/or core network #B, but may be included in the PLMN. In other words, the AAA server may be a core network device, or a device outside the core network. For example, the AAA server may be a server device within the PLMN managed by a third party.

Note that in FIG. 2, for the sake of simplicity, each device and function is shown one by one, but multiple similar devices and functions may be configured in the mobile communication system 1. Specifically, the mobile communication system 1 may be configured with multiple devices and functions such as UE#A10, E-UTRAN80, MME40, SGW35, PGW-U30, PGW-C32, PCRF60, HSS50, 5G AN120, AMF140, UPF130, SMF132, PCF160, and/or UDM150.

[2. Configuration of each device]
Next, the configuration of each device (UE, and/or access network device, and/or core network device) used in each embodiment will be described with reference to the drawings. Each device may be configured as physical hardware, may be configured as logical (virtual) hardware configured on general-purpose hardware, or may be configured as software. Furthermore, at least a part (including all) of the functions of each device may be configured as physical hardware, logical hardware, or software.

Each storage unit (storage unit #A340, storage unit #A440, storage unit #B540, storage unit #A640, storage unit #B740) in each device/function described below is composed of, for example, a semiconductor memory, a solid state drive (SSD), a hard disk drive (HDD), etc. Each storage unit can store not only information that was originally set at the time of shipment, but also various information transmitted and received between devices/functions other than the device/function itself (for example, UE, and/or access network device, and/or core network device, and/or PDN, and/or DN). Each storage unit can also store identification information, control information, flags, parameters, etc. contained in control messages transmitted and received in various communication procedures described later. Each storage unit may also store this information for each UE. Each storage unit can also store control messages and user data transmitted and received between devices/functions included in 5GS and/or EPS when interworking is performed between 5GS and EPS. At this time, not only those transmitted and received via the N26 interface but also those transmitted and received without passing through the N26 interface can be stored.

[2.1. UE device configuration]
First, an example of the device configuration of UE (User Equipment) will be described with reference to Fig. 3. The UE is composed of a control unit #A300, an antenna 310, a transceiver unit #A320, and a memory unit #A340. The control unit #A300, the transceiver unit #A320, and the memory unit #A340 are connected via a bus. The transceiver unit #A320 is connected to the antenna 310.

The control unit #A300 is a functional unit that controls the operation and functions of the entire UE. The control unit #A300 realizes various processes in the UE by reading and executing various programs stored in the memory unit #A340 as necessary.

The transceiver unit #A320 is a functional unit for wirelessly communicating with a base station device (eNB or gNB) in the access network via an antenna. That is, the UE can use the transceiver unit #A320 to transmit and receive user data and/or control information between an access network device, and/or a core network device, and/or a PDN, and/or a DN.

Explaining in detail with reference to FIG. 2, the UE can communicate with a base station device (eNB) in the E-UTRAN via the LTE-Uu interface by using the transceiver unit #A320. The UE can also communicate with a base station device (gNB) in the 5G AN by using the transceiver unit #A320. The UE can also transmit and receive AMF and NAS (Non-Access-Stratum) messages via the N1 interface by using the transceiver unit #A320. However, since the N1 interface is logical, in reality, communication between the UE and the AMF is performed via the 5G AN.

Memory unit #A340 is a functional unit for storing programs, user data, control information, etc. required for each operation of the UE.

[2.2. gNB device configuration]
Next, an example of the device configuration of the gNB will be described with reference to Fig. 4. The gNB is composed of a control unit #B500, an antenna 510, a network connection unit #B520, a transceiver unit #B530, and a memory unit #B540. The control unit #B500, the network connection unit #B520, the transceiver unit #B530, and the memory unit #B540 are connected via a bus. The transceiver unit #B530 is connected to the antenna 510.

The control unit #B500 is a functional unit that controls the operation and functions of the entire gNB. The control unit #B500 realizes various processes in the gNB by reading and executing various programs stored in the memory unit #B540 as necessary.

The network connection unit #B520 is a functional unit that enables the gNB to communicate with the AMF and/or UPF. That is, the gNB can send and receive user data and/or control information between the AMF and/or UPF using the network connection unit #B520.

The transceiver unit #B530 is a functional unit for wireless communication with the UE via the antenna 510. That is, the gNB can transmit and receive user data and/or control information between the UE and the gNB using the transceiver unit #B530.

Explaining in detail with reference to FIG. 2, a gNB in a 5G AN can communicate with an AMF via an N2 interface by using a network connection unit #B520, and can communicate with a UPF via an N3 interface. The gNB can also communicate with a UE by using a transceiver unit #B530.

The memory unit #B540 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the gNB.

[2.3. AMF device configuration]
Next, an example of the device configuration of the AMF will be described with reference to Fig. 5. The AMF is composed of a control unit #B700, a network connection unit #B720, and a storage unit #B740. The control unit #B700, the network connection unit #B720, and the storage unit #B740 are connected via a bus. The AMF may be a node that handles the control plane.

The control unit #B700 is a functional unit that controls the operation and functions of the entire AMF. The control unit #B700 realizes various processes in the AMF by reading and executing various programs stored in the memory unit #B740 as necessary.

The network connection unit #B720 is a functional unit that enables the AMF to connect to a base station device (gNB), and/or an SMF, and/or a PCF, and/or an UDM, and/or an SCEF in a 5G AN. In other words, the AMF can use the network connection unit #B720 to transmit and receive user data and/or control information between a base station device (gNB), and/or an SMF, and/or a PCF, and/or an UDM, and/or an SCEF in a 5G AN.

Explaining in detail with reference to FIG. 2, the AMF in the 5GCN can communicate with the gNB via the N2 interface by using the network connection unit #A620, can communicate with the UDM via the N8 interface, can communicate with the SMF via the N11 interface, and can communicate with the PCF via the N15 interface. The AMF can also send and receive NAS messages with the UE via the N1 interface by using the network connection unit #A620. However, since the N1 interface is logical, in reality, communication between the UE and the AMF is performed via the 5G AN. In addition, if the AMF supports the N26 interface, it can communicate with the MME via the N26 interface by using the network connection unit #A620.

Memory unit #B740 is a functional unit for storing programs, user data, control information, etc. required for each operation of AMF.

The AMF has functions such as exchanging control messages with the RAN using the N2 interface, exchanging NAS messages with the UE using the N1 interface, encrypting and protecting the integrity of NAS messages, registration management (RM) functions, connection management (CM) functions, reachability management functions, mobility management functions for UEs, etc., transferring SM (Session Management) messages between the UE and the SMF, access authentication (Access Authorization) functions, security anchor functionality (SEA), security context management (SCM), a function to support the N2 interface for the N3IWF (Non-3GPP Interworking Function), a function to support sending and receiving NAS signals with the UE via the N3IWF, and authenticating UEs connected via the N3IWF.

In addition, in registration management, the RM state of each UE is managed. The RM state may be synchronized between the UE and the AMF. There are two RM states: the unregistered state (RM-DEREGISTERED state) and the registered state (RM-REGISTERED state). In the RM-DEREGISTERED state, the UE is not registered in the network, and therefore the UE context in the AMF does not have valid location information or routing information for the UE, and therefore the AMF cannot reach the UE. In the RM-REGISTERED state, the UE is registered in the network, and therefore the UE can receive services that require registration with the network. The RM state may be expressed as a 5GMM state. In this case, the RM-DEREGISTERED state may be expressed as a 5GMM-DEREGISTERED state, and the RM-REGISTERED state may be expressed as a 5GMM-REGISTERED state.

In other words, 5GMM-REGISTERED may be a state in which each device has established a 5GMM context, or a state in which a PDU session context has been established. When each device is 5GMM-REGISTERED, UE#A10 may start sending and receiving user data and control messages, and may respond to paging. Furthermore, when each device is 5GMM-REGISTERED, UE#A10 may execute registration procedures other than the registration procedure for initial registration, and/or a service request procedure.

Furthermore, 5GMM-DEREGISTERED may be a state in which each device has not established a 5GMM context, a state in which the location information of UE#A10 is not known to the network, or a state in which UE#A10 is unreachable by the network. When each device is 5GMM-DEREGISTERED, UE#A10 may initiate a registration procedure or establish a 5GMM context by performing the registration procedure.

In addition, in connection management, the CM state of each UE is managed. The CM state may be synchronized between the UE and the AMF. The CM state includes a non-connected state (CM-IDLE state) and a connected state (CM-CONNECTED state). In the CM-IDLE state, the UE is in the RM-REGISTERED state, but does not have a NAS signaling connection established with the AMF via the N1 interface. In the CM-IDLE state, the UE does not have an N2 interface connection (N2 connection) or an N3 interface connection (N3 connection). On the other hand, in the CM-CONNECTED state, the UE has a NAS signaling connection established with the AMF via the N1 interface. In the CM-CONNECTED state, the UE may have an N2 interface connection (N2 connection) and/or an N3 interface connection (N3 connection).

Furthermore, in connection management, the CM state in 3GPP access and the CM state in non-3GPP access may be managed separately. In this case, the CM state in 3GPP access may be a non-connected state in 3GPP access (CM-IDLE state over 3GPP access) and a connected state in 3GPP access (CM-CONNECTED state over 3GPP access). Furthermore, the CM state in non-3GPP access may be a non-connected state in non-3GPP access (CM-IDLE state over non-3GPP access) and a connected state in non-3GPP access (CM-CONNECTED state over non-3GPP access). The non-connected state may be expressed as an idle mode, and the connected state mode may be expressed as a connected mode.

The CM state may be expressed as 5GMM mode. In this case, the unconnected state may be expressed as 5GMM unconnected mode (5GMM-IDLE mode), and the connected state may be expressed as 5GMM connected mode (5GMM-CONNECTED mode). Furthermore, the unconnected state in 3GPP access may be expressed as 5GMM unconnected mode in 3GPP access (5GMM-IDLE mode over 3GPP access), and the connected state in 3GPP access may be expressed as 5GMM connected mode in 3GPP access (5GMM-CONNECTED mode over 3GPP access). Furthermore, the unconnected state in non-3GPP access may be expressed as 5GMM unconnected mode in non-3GPP access (5GMM-IDLE mode over non-3GPP access), and the connected state in non-3GPP access may be expressed as 5GMM connected mode in non-3GPP access (5GMM-CONNECTED mode over non-3GPP access). Note that the 5GMM unconnected mode may be expressed as idle mode, and the 5GMM connected mode may be expressed as connected mode.

In addition, one or more AMFs may be placed within core network #B. In addition, the AMF may be an NF that manages one or more NSIs (Network Slice Instances). In addition, the AMF may be a shared CP function (CCNF; Common CPNF (Control Plane Network Function)) shared between multiple NSIs.

In addition, the N3IWF is a device and/or function that is located between the non-3GPP access and the 5GCN when the UE connects to the 5GS via a non-3GPP access.

[2.4. SMF device configuration]
Next, an example of the device configuration of the SMF will be explained using Fig. 5. The SMF is made up of a control unit #B700, a network connection unit #B720, and a storage unit #B740. The control unit #B700, the network connection unit #B720, and the storage unit #B740 are connected via a bus. The SMF may be a node that handles the control plane.

The control unit #B700 is a functional unit that controls the operation and functions of the entire SMF. The control unit #B700 realizes various processes in the SMF by reading and executing various programs stored in the memory unit #B740 as necessary.

The network connection unit #B720 is a functional unit that enables the SMF to connect to the AMF, and/or the UPF, and/or the PCF, and/or the UDM. In other words, the SMF can use the network connection unit #B720 to send and receive user data and/or control information between the AMF, and/or the UPF, and/or the PCF, and/or the UDM.

Explaining in more detail with reference to Figure 2, the SMF in the 5GCN can communicate with the AMF via the N11 interface, can communicate with the UPF via the N4 interface, can communicate with the PCF via the N7 interface, and can communicate with the UDM via the N10 interface, by using network connection unit #A620.

Memory unit #B740 is a functional unit for storing programs, user data, control information, etc. required for each operation of SMF.

The SMF has a session management function such as establishing, modifying, and releasing PDU sessions, an IP address allocation for UEs and its management function, a UPF selection and control function, a UPF setting function for routing traffic to the appropriate destination (destination), a function for sending and receiving the SM portion of NAS messages, a function for notifying that downlink data has arrived (Downlink Data Notification), a function for providing AN-specific (for each AN) SM information that is sent to the AN via the N2 interface via the AMF, a function for determining the SSC mode (Session and Service Continuity mode) for the session, and a roaming function.

[2.5. UPF device configuration]
Next, an example of the device configuration of the UPF will be described with reference to Fig. 5. The UPF is made up of a control unit #B700, a network connection unit #B720, and a storage unit #B740. The control unit #B700, the network connection unit #B720, and the storage unit #B740 are connected via a bus. The UPF may be a node that handles the control plane.

The control unit #B700 is a functional unit that controls the operation and functions of the entire UPF. The control unit #B700 realizes various processes in the UPF by reading and executing various programs stored in the memory unit #B740 as necessary.

The network connection unit #B720 is a functional unit that enables the UPF to connect to a base station device (gNB), and/or an SMF, and/or a DN in the 5G AN. In other words, the UPF can use the network connection unit #B720 to transmit and receive user data and/or control information between a base station device (gNB), and/or an SMF, and/or a DN in the 5G AN.

Explaining in more detail with reference to Figure 2, the UPF in the 5GCN can communicate with a gNB via the N3 interface, can communicate with an SMF via the N4 interface, can communicate with a DN via the N6 interface, and can communicate with other UPFs via the N9 interface, by using network connection unit #A620.

Memory unit #B740 is a functional unit for storing programs, user data, control information, etc. required for each operation of the UPF.

The UPF has functions such as acting as an anchor point for intra-RAT mobility or inter-RAT mobility, acting as an external PDU session point for interconnecting to DNs (i.e., as a gateway between DN and core network #B, forwarding user data), routing and forwarding packets, a UL CL (Uplink Classifier) function that supports routing of multiple traffic flows to one DN, a branching point function that supports multi-homed PDU sessions, QoS (Quality of Service) processing function for the user plane, verification of uplink traffic, buffering of downlink packets, and triggering downlink data notifications.

The UPF may also be a gateway for IP communication and/or non-IP communication. The UPF may also have a function for forwarding IP communication, and may also have a function for converting between non-IP communication and IP communication. Furthermore, multiple gateways may be gateways that connect core network #B and a single DN. The UPF may also have connectivity with other NFs, and may be connected to each device via other NFs.

The user plane refers to user data transmitted and received between the UE and the network. The user plane may be transmitted and received using a PDN connection or a PDU session. Furthermore, in the case of EPS, the user plane may be transmitted and received using the LTE-Uu interface, and/or the S1-U interface, and/or the S5 interface, and/or the S8 interface, and/or the SGi interface. Furthermore, in the case of 5GS, the user plane may be transmitted and received via an interface between the UE and the NG RAN, and/or the N3 interface, and/or the N9 interface, and/or the N6 interface. Hereinafter, the user plane may be expressed as the U-Plane.

Furthermore, the control plane refers to control messages transmitted and received to control UE communications, etc. The control plane may be transmitted and received using a NAS (Non-Access-Stratum) signaling connection between the UE and MME. Furthermore, in the case of EPS, the control plane may be transmitted and received using the LTE-Uu interface and the S1-MME interface. Furthermore, in the case of 5GS, the control plane may be transmitted and received using the interface between the UE and NG RAN and the N2 interface. Hereinafter, the control plane may be expressed as the control plane or the C-Plane.

Furthermore, the U-Plane (User Plane; UP) may be a communication path for transmitting and receiving user data and may be composed of multiple bearers. Furthermore, the C-Plane (Control Plane; CP) may be a communication path for transmitting and receiving control messages and may be composed of multiple bearers.

[2.6. Description of other devices and/or functions and/or identification information in this embodiment]
Next, other devices and/or functions and/or identification information will be described.

A network refers to at least a part of the access network #B, core network #B, and DN. Furthermore, one or more devices included in at least a part of the access network #B, core network #B, and DN may be referred to as a network or a network device. In other words, when a network transmits, receives, and/or processes messages, it may mean that devices within the network (network devices and/or control devices) transmit, receive, and/or process messages. Conversely, when a device within the network transmits, receives, receives, and/or processes messages, it may mean that the network transmits, receives, and/or processes messages.

In addition, the SM (Session Management) message (also referred to as a NAS (Non-Access-Stratum) SM message) may be a NAS message used in procedures for SM, and may be a control message transmitted and received between UE#A10 and SMF#A230 via AMF#A240. Furthermore, the SM message may include a PDU session establishment request message, a PDU session establishment accept message, a PDU session establishment reject message, a PDU session modification request message, a PDU session modification command message, a PDU session modification complete message, a PDU session modification command reject message, a PDU session modification reject message, a PDU session release request message, a PDU session release reject message, a PDU session release command message, a PDU session release complete message, etc. Furthermore, the procedure for SM or the SM procedure may include a PDU session establishment procedure, a PDU session modification procedure, and a UE-requested PDU session release procedure. Each procedure may be initiated by the UE or may be initiated by the NW.

In addition, the MM (Mobility management) message (also referred to as a NAS MM message) may be a NAS message used in procedures for MM, and may be a control message transmitted and received between UE#A10 and AMF#A240. Furthermore, the MM message may include a registration request message, a registration accept message, a registration reject message, a de-registration request message, a de-registration accept message, a configuration update command message, a configuration update complete message, a service request message, a service accept message, a service reject message, a notification message, a notification response message, and the like. In addition, the procedures for MM or MM procedures may include a registration procedure, a de-registration procedure, a generic UE configuration update procedure, an authentication and authorization procedure, a service request procedure, a paging procedure, and a notification procedure.

In addition, the 5GS (5G System) service may be a connection service provided using the core network #B190. Furthermore, the 5GS service may be a service different from the EPS service, or may be a service similar to the EPS service.

In addition, non-5GS services may be services other than 5GS services and may include EPS services and/or non-EPS services.

In addition, the PDN (Packet Data Network) type indicates the type of PDN connection, and can be IPv4, IPv6, IPv4v6, or non-IP. If IPv4 is specified, it indicates that data will be sent and received using IPv4. If IPv6 is specified, it indicates that data will be sent and received using IPv6. If IPv4v6 is specified, it indicates that data will be sent and received using either IPv4 or IPv6. If non-IP is specified, it indicates that communication will not be using IP, but will be using a communication method other than IP.

A PDU (Protocol Data Unit/Packet Data Unit) session can be defined as an association between a DN that provides a PDU connectivity service and a UE, but may also be connectivity established between a UE and an external gateway. In 5GS, a UE can transmit and receive user data between a DN and the DN using a PDU session by establishing a PDU session via an access network #B and a core network #B. Here, this external gateway may be a UPF, a SCEF, etc. A UE can transmit and receive user data between a device such as an application server located in a DN and the DN using a PDU session.

Each device (UE, and/or access network device, and/or core network device) may associate one or more identification information with a PDU session and manage it. The identification information may include one or more of the DNN, QoS rule, PDU session type, application identification information, NSI identification information, access network identification information, and SSC mode, and may further include other information. Furthermore, when multiple PDU sessions are established, each identification information associated with a PDU session may be the same or different.

Furthermore, the DNN (Data Network Name) may be identification information that identifies a core network and/or an external network such as a DN. Furthermore, the DNN can also be used as information for selecting a gateway such as PGW#A30/UPF#A235 that connects the core network B190. Furthermore, the DNN may be equivalent to an APN (Access Point Name).

The PDU (Protocol Data Unit/Packet Data Unit) session type indicates the type of PDU session, and can be IPv4, IPv6, Ethernet, or Unstructured. If IPv4 is specified, it indicates that data will be sent and received using IPv4. If IPv6 is specified, it indicates that data will be sent and received using IPv6. If Ethernet is specified, it indicates that Ethernet frames will be sent and received. Ethernet may also indicate that communication using IP is not performed. If Unstructured is specified, it indicates that data will be sent and received to an application server or the like in the DN using Point-to-Point (P2P) tunneling technology. As the P2P tunneling technology, for example, UDP/IP encapsulation technology may be used. In addition to the above, the PDU session type may also include IP. IP can be specified when the UE is capable of using both IPv4 and IPv6.

A PLMN (Public Land Mobile Network) is a communication network that provides mobile wireless communication services. A PLMN is a network managed by an operator, which is a telecommunications carrier, and the operator can be identified by the PLMN ID. A PLMN that matches the MCC (Mobile Country Code) and MNC (Mobile Network Code) of the UE's IMSI (International Mobile Subscriber Identity) may be a Home PLMN (HPLMN). Furthermore, the UE may retain an Equivalent HPLMN list in the USIM to identify one or more EPLMNs (Equivalent HPLMNs). A PLMN that is different from the HPLMN and/or EPLMN may be a Visited PLMN (VPLMN). A PLMN to which the UE has successfully registered may be a Registered PLMN (RPLMN).

A network slice (NS) is a logical network that provides specific network capabilities and network characteristics. In 5GS, a UE and/or a network can support network slices (NW slices; NS). A network slice may also be simply referred to as a slice.

A network slice instance (NSI) is composed of an instance (entity) of a network function (NF) and a set of required resources, and forms a network slice to be deployed. Here, an NF is a processing function in a network, which is adopted or defined by 3GPP. An NSI is an entity of an NS, of which one or more are configured in a core network #B. An NSI may also be composed of a virtual NF (Network Function) generated using an NST (Network Slice Template). Here, an NST is associated with a resource requirement for providing a required communication service or capability, and is a logical representation of one or more NFs. In other words, an NSI may be a collection in a core network #B190 composed of multiple NFs. An NSI may also be a logical network configured to separate user data delivered by a service, etc. An NS may be configured with one or more NFs. An NF configured in an NS may or may not be a device shared with other NSs. A UE and/or a device in the network may be assigned to one or more NSs based on registration information such as an NSSAI, an S-NSSAI, an UE usage type, an NSI ID, or an APN. The UE usage type is a parameter value included in the registration information of the UE that is used to identify the NSI. The UE usage type may be stored in the HSS. The AMF may select an SMF and a UPF based on the UE usage type.

S-NSSAI (Single Network Slice Selection Assistance Information) is information for identifying an NS. S-NSSAI may be composed of only SST (Slice/Service type) or may be composed of both SST and SD (Slice Differentiator). Here, SST is information indicating the expected operation of NS in terms of functions and services. SD may be information for interpolating SST when selecting one NSI from multiple NSIs indicated by SST. S-NSSAI may be information specific to each PLMN or may be standard information common among PLMNs. The network may store one or more S-NSSAI as a default S-NSSAI in the registration information of the UE. In addition, when S-NSSAI is the default S-NSSAI, if the UE does not send a valid S-NSSAI to the network in the registration request message, the network may provide the NS related to the UE.

Furthermore, NSSAI (Network Slice Selection Assistance Information) is a collection of S-NSSAI. Each S-NSSAI included in the NSSAI is information that assists the access network or core network in selecting an NSI. The UE may store the NSSAI authorized by the network for each PLMN. Furthermore, the NSSAI may be information used to select an AMF.

Furthermore, the configured NSSAI is an NSSAI that is provided and stored in the UE. The UE may store the configured NSSAI for each PLMN. The configured NSSAI may be information configured by the network (or PLMN). The S-NSSAI included in the configured NSSAI may be expressed as the configured S-NSSAI. The configured S-NSSAI may be configured to include the S-NSSAI and the mapped S-NSSAI.

In addition, the requested NSSAI is an NSSAI provided by the UE to the network during the registration procedure. The requested NSSAI may be an allowed NSSAI or a configured NSSAI stored by the UE. Specifically, the requested NSSAI may be information indicating a network slice that the UE wishes to access. The S-NSSAI included in the requested NSSAI may be expressed as a requested S-NSSAI. For example, the requested NSSAI is transmitted included in an NAS message transmitted from the UE to the network, such as a registration request message or a PDU session establishment request message, or an RRC (Radio Resource Control) message including a NAS (Non-Access-Stratum) message.

Furthermore, the allowed NSSAI is information indicating one or more network slices to which the UE is allowed. In other words, the allowed NSSAI is information that identifies a network slice to which the network has allowed the UE to connect. The UE and the network each store and manage the allowed NSSAI for each access (3GPP access or non-3GPP access) as information of the UE. The S-NSSAI included in the allowed NSSAI may be expressed as the allowed S-NSSAI. The allowed S-NSSAI may be configured to include the S-NSSAI and the mapped S-NSSAI.

A mapped S-NSSAI is an S-NSSAI of an HPLMN that is mapped to an S-NSSAI of a registered PLMN in a roaming scenario. The UE may store one or more mapped S-NSSAIs that are mapped to the configured NSSAI and the S-NSSAI included in the Allowed NSSAI for each access type. Additionally, the UE may store one or more mapped S-NSSAIs for the first NSSAI and/or the S-NSSAI included in the rejected NSSAI.

In addition, the rejected NSSAI is information indicating one or more network slices to which the UE is not permitted. In other words, the rejected NSSAI is information identifying a network slice to which the network does not permit the UE to connect. The rejected NSSAI may be information including one or more combinations of an S-NSSAI and a rejection reason value. Here, the rejection reason value is information indicating the reason why the network rejects the corresponding S-NSSAI. The UE and the network may store and manage the rejected NSSAI appropriately, based on the rejection reason value associated with each S-NSSAI. Furthermore, the rejected NSSAI may be included in an NAS message transmitted from the network to the UE, such as a registration acceptance message, a configuration update command, or a registration rejection message, or in an RRC message including a NAS message. The S-NSSAI included in the rejected NSSAI may be expressed as a rejected S-NSSAI. The rejected NSSAI may be any one of the first to third rejected NSSAIs, the pending NSSAI, and the first NSSAI, or a combination of these. The S-NSSAI included in the rejected NSSAI may be expressed as a rejected S-NSSAI. The rejected S-NSSAI may be configured to include an S-NSSAI and a mapped S-NSSAI.

Here, the first rejected NSSAI is a set of one or more S-NSSAIs that are unavailable in the current PLMN among the S-NSSAIs included in the requested NSSAI by the UE. The first rejected NSSAI may be a 5GS rejected NSSAI for the current PLMN, a rejected S-NSSAI for the current PLMN, or an S-NSSAI included in the rejected NSSAI for the current PLMN. The first rejected NSSAI may be a rejected NSSAI stored by the UE or the NW, or may be a rejected NSSAI transmitted from the NW to the UE. When the first rejected NSSAI is a rejected NSSAI transmitted from the NW to the UE, the first rejected NSSAI may be information including one or more combinations of an S-NSSAI and a reason value. The rejection reason value at this time may be "S-NSSAI is not available in the current PLMN" or may be information indicating that the S-NSSAI associated with the rejection reason value is not available in the current PLMN.

The first rejected NSSAI is valid for the entire registered PLMN. In other words, the UE and/or NW may treat the first rejected NSSAI and the S-NSSAI contained in the first rejected NSSAI as information independent of the access type. In other words, the first rejected NSSAI may be information valid for 3GPP access and non-3GPP access.

The UE may delete the first rejected NSSAI from memory if it transitions to an unregistered state for the current PLMN in both 3GPP access and non-3GPP access. In other words, if the UE transitions to an unregistered state for the current PLMN via an access, or if the UE successfully registers to a new PLMN via an access, or if the UE fails to register to the new PLMN via an access and transitions to an unregistered state, and if the UE is not registered via the other access (unregistered state), the UE deletes the first rejected NSSAI.

The second rejected NSSAI is a set of one or more S-NSSAIs that are not available in the current registration area among the S-NSSAIs included in the requested NSSAI by the UE. The second rejected NSSAI may be a 5GS rejected NSSAI for the current registration area. The second rejected NSSAI may be a rejected NSSAI stored by the UE or the NW, or may be a rejected NSSAI transmitted from the NW to the UE. When the second rejected NSSAI is a rejected NSSAI transmitted from the NW to the UE, the second rejected NSSAI may be information including one or more combinations of an S-NSSAI and a reason value. In this case, the reason value may be "S-NSSAI is not available in the current registration area" or may be information indicating that the S-NSSAI associated with the reason value is not available in the current registration area.

The second rejected NSSAI is valid within the current registration area. That is, the UE and/or NW may treat the second rejected NSSAI and the S-NSSAI contained in the second rejected NSSAI as information for each access type. That is, the second rejected NSSAI may be information valid for each of 3GPP access or non-3GPP access. That is, once the UE transitions to an unregistered state for a certain access, it may delete the second rejected NSSAI from its memory.

The third rejected NSSAI is an S-NSSAI that requires Network Slice-Specific Authentication and Authorization, and is a set of one or more S-NSSAIs for which Network Slice-Specific Authentication and Authorization for the S-NSSAI has failed or been revoked. The third rejected NSSAI may be an NSSAI stored by the UE and/or NW, or may be transmitted from the NW to the UE. When the third rejected NSSAI is transmitted from the NW to the UE, the third rejected NSSAI may be information including one or more combinations of an S-NSSAI and a rejection reason value. The rejection reason value at this time may be "S-NSSAI is not available due to the failed or revoked network slice-specific authorization and authentication" or may be information indicating that the network slice-specific authentication and authorization for the S-NSSAI associated with the rejection reason value has failed or been revoked.

The third rejected NSSAI is valid across the entire registered PLMN. In other words, the UE and/or NW may treat the third rejected NSSAI and the S-NSSAI included in the third rejected NSSAI as information independent of the access type. In other words, the third rejected NSSAI may be information valid for 3GPP access and non-3GPP access. The third rejected NSSAI may be an NSSAI different from the rejected NSSAI. The third rejected NSSAI may be the first rejected NSSAI.

The third rejected NSSAI is a rejected NSSAI that identifies a slice that the UE has rejected from the core network due to failure or cancellation of Network Slice-Specific Authentication and Authorization. Specifically, while the UE stores the third rejected NSSAI, the UE does not initiate a registration request procedure for the S-NSSAI included in the third rejected NSSAI. The third rejected NSSAI may be identification information including one or more S-NSSAIs received from the core network in association with a rejection reason value indicating a failure of Network Slice-Specific Authentication and Authorization. The third rejected NSSAI is information that is independent of the access type. Specifically, when the UE stores the third rejected NSSAI, the UE may not attempt to transmit a registration request message including the S-NSSAI included in the third rejected NSSAI to both 3GPP access and non-3GPP access. Alternatively, the UE may transmit a registration request message including the S-NSSAI included in the third rejected NSSAI based on the UE policy. Alternatively, the UE may delete the third rejected NSSAI based on the UE policy and transition to a state in which the UE can transmit a registration request message including the S-NSSAI included in the third rejected NSSAI. In other words, when the UE transmits a registration request message including the S-NSSAI included in the third rejected NSSAI based on the UE policy, the UE may delete the S-NSSAI from the third rejected NSSAI.

The first NSSAI is information including one or more S-NSSAIs that have reached the maximum number of UEs per network slice. The first NSSAI may be a rejected NSSAI, an allowed NSSAI, or a pending NSSAI. The first NSSAI may be an NSSAI stored by the UE and/or NW, or an NSSAI transmitted from the NW to the UE.

When the first NSSAI is transmitted from the NW to the UE, the first NSSAI may be information including one or more pieces of information including at least one of the S-NSSAI, the mapped S-NSSAI, a reason value, a back-off timer value, and information indicating the validity range of the back-off timer value. In this case, the reason value may be "S-NSSAI has reached the maximum number of UEs per network slice" or may be information indicating that the maximum number of UEs allowed for the S-NSSAI associated with the rejection reason value has been reached. Here, the reason value may be a rejection reason value included in the Rejected NSSAI or may be flag information. Furthermore, in this case, the back-off timer value may be information indicating a period during which the UE is prohibited from transmitting MM messages and SM messages using the S-NSSAI related to the corresponding S-NSSAI or the mapped S-NSSAI.

Furthermore, the information indicating the validity range of the backoff timer value may be information indicating whether the backoff timer value applies to the current PLMN (Public Land Mobile Network), applies to all PLMNs, or is valid in the current registration area.

The first NSSAI may be valid for the entire registered PLMN, for all PLMNs, or within the registration area. If the first NSSAI is valid for the entire registered PLMN or for all PLMNs, the UE and/or NW may treat the first NSSAI and the S-NSSAI contained in the first NSSAI as information independent of the access type. If the first NSSAI is valid within the registration area, the UE and/or NW may treat the first NSSAI and the S-NSSAI contained in the first NSSAI as information specific to the access type.

The first NSSAI may be an allowed NSSAI, a rejected NSSAI, a pending NSSAI, or information different from these.

A pending NSSAI is a collection of one or more S-NSSAIs for which the network requires network slice specific authentication, for which network slice specific authentication has not been completed, and which cannot be used in the current PLMN. The pending NSSAI may be a 5GS Rejected NSSAI due to network slice specific authentication and authorization or a pending NSSAI. The pending NSSAI may be an NSSAI stored by the UE or the NW, or an NSSAI sent from the NW to the UE. Note that the pending NSSAI is not limited to the rejected NSSAI, and may be an NSSAI independent of the rejected NSSAI. When the pending NSSAI is an NSSAI sent from the NW to the UE, the pending NSSAI may be information that includes one or more combinations of an S-NSSAI and a rejection reason value. The rejection reason value at this time may be "S-NSSAI (Network slice-specific authentication and authorization is pending for the S-NSSAI)" and may be information indicating that the S-NSSAI associated with the rejection reason value is prohibited or pending use by the UE until Network slice-specific authentication and authorization for that S-NSSAI is completed.

The pending NSSAI is valid across the entire registered PLMN. In other words, the UE and/or NW may treat the third rejected NSSAI and the S-NSSAI included in the pending NSSAI as information independent of the access type. In other words, the pending NSSAI may be information valid for 3GPP access and non-3GPP access. The pending NSSAI may be an NSSAI different from the rejected NSSAI. The pending NSSAI may be the first rejected NSSAI.

The pending NSSAI is an NSSAI consisting of one or more S-NSSAIs that identify slices for which the UE is pending a procedure. Specifically, while the UE stores the pending NSSAI, the UE does not initiate a registration request procedure for the S-NSSAI included in the pending NSSAI. In other words, the UE does not use the S-NSSAI included in the pending NSSAI during the registration procedure until the Network Slice-Specific Authentication and Authorization for the S-NSSAI included in the pending NSSAI is completed. The pending NSSAI is identification information that includes one or more S-NSSAIs received from the core network in association with a rejection reason value indicating pending for Network Slice-Specific Authentication and Authorization. The pending NSSAI is information that is independent of the access type. Specifically, when the UE stores the pending NSSAI, the UE does not attempt to transmit a registration request message including the S-NSSAI included in the pending NSSAI to both 3GPP access and non-3GPP access.

A tracking area is a single or multiple ranges managed by the core network that can be represented by the location information of UE#A10. A tracking area may be composed of multiple cells. Furthermore, a tracking area may be an area in which control messages such as paging are broadcast, or an area in which UE#A10 can move without performing a handover procedure. Furthermore, a tracking area may be a routing area, a location area, or anything similar to these. Hereinafter, a tracking area may be a TA (Tracking Area). A tracking area may be identified by a TAI (Tracking Area Identity) composed of a TAC (Tracking area code) and a PLMN.

A registration area is a collection of one or more TAs that the AMF assigns to a UE. Note that while UE#A10 is moving within one or more TAs included in the registration area, it may be able to move without sending or receiving a signal for updating the tracking area. In other words, a registration area may be a group of information indicating areas in which UE#A10 can move without performing a tracking area update procedure. A registration area may be identified by a TAI list consisting of one or more TAIs.

UE ID is information for identifying a UE. Specifically, for example, the UE ID may be SUCI (SUbscription Concealed Identifier), or SUPI (Subscription Permanent Identifier), or GUTI (Globally Unique Temporary Identifier), or IMEI (International Mobile Subscriber Identity), or IMEISV (IMEI Software Version), or TMSI (Temporary Mobile Subscriber Identity). Alternatively, the UE ID may be other information set in an application or network. Furthermore, the UE ID may be information for identifying a user.

The Network Slice-Specific Authentication and Authorization function is a function for realizing authentication and authorization specific to a network slice. With network slice-specific authentication and authorization, authentication and authorization of a UE can be performed outside the core network, such as by a 3rd party. A PLMN and a network device having the Network Slice-Specific Authentication and Authorization function can execute a Network Slice-Specific Authentication and Authorization procedure for a certain S-NSSAI based on the registration information of the UE. Furthermore, a UE having the Network Slice-Specific Authentication and Authorization function can manage and store rejected NSSAIs for pending Network Slice-Specific Authentication and Authorization and/or rejected NSSAIs for failed Network Slice-Specific Authentication and Authorization. In this document, Network Slice-Specific Authentication and Authorization may be referred to as a network slice-specific authentication and authorization procedure or an authentication and authorization procedure.

An S-NSSAI that requires Network Slice-Specific Authentication and Authorization is an S-NSSAI that requires Network Slice-Specific Authentication and Authorization that is managed by a core network and/or a core network device. The core network and/or core network device may store an S-NSSAI that requires Network Slice-Specific Authentication and Authorization by storing the S-NSSAI in association with information indicating whether or not Network Slice-Specific Authentication and Authorization is required. The core network and/or core network device may further store an S-NSSAI that requires Network Slice-Specific Authentication and Authorization in association with information indicating whether or not Network Slice-Specific Authentication and Authorization has been completed, or information indicating that Network Slice-Specific Authentication and Authorization has been completed and permitted or successful. The core network and/or core network device may manage an S-NSSAI that requires Network Slice-Specific Authentication and Authorization as information that is not related to an access network.

The management of the maximum number of UEs connected to a slice refers to managing the maximum number of UEs that can be registered in a network slice or S-NSSAI at the same time. Here, the UE to be registered in the network slice or S-NSSAI may be stored by including the S-NSSAI indicating the network slice in the Allowed NSSAI. A device in a network that supports the function of managing the maximum number of UEs connected to a slice can store, for each S-NSSAI, whether or not the management of the maximum number of UEs connected to the slice is required, and can further check during the registration procedure whether or not the registered UEs have reached a constant number, which is the maximum number. Furthermore, each device that supports the function of managing the maximum number of UEs connected to a slice may be capable of storing a first NSSAI. In this document, the maximum number of UEs connected to a slice may be expressed as the maximum number of UEs connected to each slice, or the maximum number of UEs that can be registered in the network slice or S-NSSAI, or the maximum number of UEs, or a constant.

The back-off timer is a timer for prohibiting the UE from sending an MM message and/or starting a procedure using an SM message. The back-off timer is managed and executed by the UE. The back-off timer may be associated with an S-NSSAI. The UE may be in a state in which the sending of MM messages and/or the sending of SM messages using the S-NSSAI is prohibited, restricted, or limited while the back-off timer associated with the S-NSSAI is valid. These restrictions may be restrictions due to 5GS congestion management, or may be restrictions that include restrictions due to 5GS congestion management.

The backoff timer may be a timer that is started and/or stopped on a per S-NSSAI and/or per PLMN basis.

Specifically, the back-off timer may be associated with an S-NSSAI and may be a timer for prohibiting the transmission of MM messages and/or SM messages using a particular S-NSSAI. In other words, the UE may be configured not to transmit MM messages and/or SM messages using that particular S-NSSAI while this timer is counting.

Furthermore, while this timer is counting, the UE may configure the new PLMN to permit transmission of MM messages and/or SM messages that were prohibited in the previous PLMN based on specific conditions described below. Note that when it is expressed that transmission of MM messages and/or SM messages that were prohibited in the previous PLMN is permitted, it may mean that transmission of MM messages and/or SM messages using the same S-NSSAI as the S-NSSAI associated with the back-off timer, and/or an S-NSSAI associated with the same S-NSSAI, and/or an S-NSSAI associated with a mapped S-NSSAI of the same S-NSSAI is permitted.

Furthermore, the back-off timer may be a timer for prohibiting the transmission of an MM message using a particular NSSAI. In other words, the UE may be configured not to transmit an MM message using that particular NSSAI and/or an NSSAI including a particular S-NSSAI while this timer is counting.

Furthermore, while this timer is counting, the UE may configure the new PLMN to permit transmission of an MM message that was prohibited in the previous PLMN based on a specific condition described later. Note that when it is expressed that transmission of an MM message that was prohibited in the previous PLMN is permitted, it may mean that transmission of an MM message using an NSSAI that is the same as the NSSAI associated with the back-off timer, and/or an NSSAI that includes the same S-NSSAI as the S-NSSAI associated with the back-off timer is permitted. Furthermore, when it is expressed that transmission of an MM message that was prohibited in the previous PLMN is permitted, it may mean that transmission of an MM message using an NSSAI that includes an S-NSSAI associated with the S-NSSAI associated with the back-off timer, and/or an NSSAI that includes an S-NSSAI associated with the mapped S-NSSAI of the S-NSSAI associated with the back-off timer is permitted.

The backoff timer may also be associated with no NSSAI and may be a timer for prohibiting transmission of an MM message using no NSSAI. In other words, UE#A10 may be configured not to transmit an MM message using no NSSAI while this timer is counting. Furthermore, UE#A10 may be configured, while this timer is counting, to permit transmission of an MM message that was prohibited in the PLMN before the change, in the new PLMN, based on specific conditions described below. Note that when it is expressed that transmission of an MM message that was prohibited in the PLMN before the change is permitted, this may mean that an MM message using no NSSAI is permitted.

Furthermore, the back-off timer may be a 5GMM timer and/or an EMM (EPS mobility management) timer. Furthermore, the back-off timer may be timer T3448 or a timer equivalent to timer T3448. In other words, the back-off timer may be the same timer as or similar to a timer for regulating communication of user data via the control plane.

Next, we will explain the identification information that is sent, received, stored, and managed by each device in this embodiment.

The first identification information is information indicating a network slice in which the UE wishes to register. The first identification information may be information including one or more S-NSSAIs associated with a network slice in which the UE wishes to register. The S-NSSAI included in the first identification information may be an S-NSSAI included in a configured NSSAI associated with the current PLMN, or an S-NSSAI included in an allowed NSSAI associated with the current PLMN. In other words, the first identification information may be an S-NSSAI included in a configured NSSAI associated with one or more current PLMNs, or an S-NSSAI included in an allowed NSSAI associated with one or more current PLMNs, or a combination of the above two. More specifically, the allowed NSSAI associated with the current PLMN may be an allowed NSSAI associated with the current PLMN and the current access type. Furthermore, the first identification information may be a Requested NSSAI of 5GS.

In addition, the S-NSSAI included in the first identification information may be a rejected NSSAI, and/or a pending NSSAI, and/or an S-NSSAI that is not included in the first NSSAI. Furthermore, the S-NSSAI included in the first identification information may be an S-NSSAI for which the back-off timer associated with that S-NSSAI or the mapped S-NSSAI of that S-NSSAI is not running.

The second identification information may be information indicating that the UE supports a function for managing the maximum number of UEs connecting to a slice. Or, the second identification information may be information indicating whether the UE supports a function for managing the maximum number of UEs connecting to a slice. The second identification information may be 5G MM capability information. The second identification information may be information indicating that the UE can store.

The tenth identification information may be information indicating that the S-NSSAI has reached the maximum number of UEs that can be registered in the network slice or the S-NSSAI. The tenth identification information may be included in the Allowed NSSAI transmitted from the network, may be included in the Rejected NSSAI transmitted from the network, may be included in the Pending NSSAI transmitted from the network, or may be transmitted from the network as information different from these.

Furthermore, the tenth identification information may be an NSSAI. Furthermore, the tenth identification information may be an Allowed NSSAI or a Rejected NSSAI. Furthermore, the tenth identification information may be a Pending NSSAI or an NSSAI different from these.

The tenth identification information may be the first NSSAI or an S-NSSAI included in the first NSSAI. The tenth identification information may be configured to include at least one of the eleventh to fifteenth identification information. Specifically, the tenth identification information may include at least one of the following information: an S-NSSAI that has reached the maximum number of UEs that can be registered in the network slice or S-NSSAI, a mapped S-NSSAI of the S-NSSAI, a reason value indicating that the maximum number of UEs that can be registered in the network slice or S-NSSAI has been reached, a back-off timer value indicating a period during which the UE is prohibited from transmitting a registration request message using the S-NSSAI, and information indicating the validity range of the back-off timer.

Furthermore, the tenth identification information may be configured to include at least one or more of a reason value indicating that the maximum number of UEs that can be registered in the network slice has been reached, a back-off timer value indicating a period during which transmission of a registration request message using no NSSAI is prohibited, and information indicating the validity range of the back-off timer. Note that the reason value indicating that the maximum number of UEs that can be registered in the network slice has been reached, the back-off timer value indicating a period during which transmission of a registration request message using no NSSAI is prohibited, and information indicating the validity range of the back-off timer may not be included in the tenth identification information and may be transmitted and received separately. Here, when the tenth identification information is included in the rejected NSSAI, the reason value included in the tenth identification information may be a rejection reason value.

The eleventh identification information may be information and/or a reason value indicating that the network has reached the maximum number of UEs that can be registered in the network slice or the S-NSSAI to the UE. The eleventh identification information may be information and/or a reason value indicating that the use of the S-NSSAI is rejected or restricted because the maximum number of UEs connected per slice has been reached. In other words, the eleventh identification information is information and a reason value indicating that the UE has been rejected or restricted from the network to use the S-NSSAI because the maximum number of UEs connected per slice has been reached. The eleventh identification information may be included in the tenth identification information and may be associated with the S-NSSAI indicated in the fourteenth identification information and/or the mapped S-NSSAI indicated in the fifteenth identification information included in the same tenth identification information. The eleventh identification information may be associated with each identification information included in the same tenth identification information. When the eleventh identification information is included in the rejected NSSAI, the eleventh identification information may be a rejection reason value. The eleventh identification information may be flag information.

Furthermore, the eleventh identification information may be a reason value indicating that connection to the slice is restricted and/or not permitted. Further, the eleventh identification information may be a reason value indicating that registration to the slice is restricted and/or not permitted.

Furthermore, the 11th identification information may be a 5GMM (5G Mobility Management) cause. Furthermore, the 11th identification information may be a 22nd 5GMM cause. Here, the 22nd 5GMM cause may be a reason value indicating congestion. Furthermore, the 22nd 5GMM cause may be information transmitted to the UE due to network congestion.

Furthermore, the 11th identification information may be a 5GMM cause other than the 22nd 5GMM cause. For example, the 11th identification information may be information transmitted to the UE due to congestion in a network slice. Furthermore, the 11th identification information may be information transmitted to the UE due to a lack of resources in a network slice. Furthermore, the 11th identification information may be a reason value indicating that the requested service cannot be provided due to insufficient resources for a particular slice.

The 12th identification information may be a value of a back-off timer. Specifically, the 12th identification information may be information indicating a period during which the network prohibits the UE from transmitting an MM message using the S-NSSAI indicated in the 14th identification information and/or the 15th identification information included in the same 10 identification information, or from transmitting an SM message other than a PDU connection release request message. In other words, the 12th identification information may be information indicating a period during which the network prohibits the UE from transmitting a registration request message using the S-NSSAI indicated in the 14th identification information and/or the 15th identification information included in the same 10 identification information.

The 12th identification information may be included in the 10th identification information and may be associated with the S-NSSAI indicated in the 14th identification information included in the same 10th identification information and/or the mapped S-NSSAI indicated in the 15th identification information. The 12th identification information may be associated with each identification information included in the same 10th identification information.

The 13th identification information is information indicating the validity range of the back-off timer. Specifically, the 13th identification information may be information indicating the validity range of the back-off timer counted by the UE using the value of the corresponding back-off timer. More specifically, the 13th identification information may be information indicating that the corresponding back-off timer is applied to the current PLMN or to all PLMNs. Additionally, or the 13th identification information may be information indicating that the corresponding back-off timer is applied to the current registration area.

Furthermore, the 13th identification information may be information indicating the scope of the restriction, or may be information indicating the scope to which the restriction applies. The restriction may be a restriction based on congestion management. More specifically, the restriction may limit the transmission of an MM message from the UE. Furthermore, the restriction may be realized by a back-off timer.

The 13th identification information may be included in the 10th identification information, and in that case, the value of the corresponding back-off timer may be a value indicated by the 12th identification information included in the same 10th identification information. Furthermore, in that case, the 13th identification information may be associated with each identification information included in the same 10th identification information.

The 14th identification information is information indicating an S-NSSAI that has reached the maximum number of UEs that can be registered per S-NSSAI. The 14th identification information may be an S-NSSAI included in the 10th identification information, and may be associated with a mapped S-NSSAI indicated in the 15th identification information included in the same 10th identification information. The 14th identification information may be associated with each identification information included in the same 10th identification information. Furthermore, the 14th identification information may be an S-NSSAI.

The 15th identity is the S-NSSAI of the HPLMN associated with the corresponding S-NSSAI. Specifically, if the current PLMN is not the HPLMN, the 15th identity may be information indicating the S-NSSAI of the HPLMN mapped to the S-NSSAI of the current PLMN.

The 15th identification information may be a mapped S-NSSAI included in the 10th identification information, or may be associated with the S-NSSAI indicated in the 14th identification information included in the same 10th identification information, in which case it may be a mapped S-NSSAI of the S-NSSAI indicated in the 14th identification information. The 15th identification information may be associated with each identification information included in the same 10th identification information. Furthermore, the 15th identification information may be a mapped S-NSSAI of the S-NSSAI indicated by the 14th identification information.

[3.1. Description of procedures used in each embodiment]
Next, procedures used in each embodiment will be described. The procedures used in each embodiment include a registration procedure. Each procedure will be described below.

In each embodiment, as shown in FIG. 2, the case where the HSS and UDM, PCF and PCRF, SMF and PGW-C, and UPF and PGW-U are configured as the same device (i.e., the same physical hardware, or the same logical hardware, or the same software) is described as an example. However, the contents described in this embodiment are also applicable to the case where these are configured as different devices (i.e., different physical hardware, or different logical hardware, or different software). For example, data may be sent and received directly between them, or data may be sent and received via the N26 interface between the AMF and MME, or data may be sent and received via the UE.

[3.2. Registration Procedure]
First, the registration procedure will be described with reference to FIG. 6. Hereinafter, this procedure refers to the registration procedure. The registration procedure is a procedure for the UE to take the initiative in registering to the access network #B and/or the core network #B and/or the DN. If the UE is not registered to the network, it can execute this procedure at any timing, such as when the power is turned on. In other words, if the UE is in a deregistered state (5GMM-DEREGISTERED state), it can start this procedure at any timing. Furthermore, each device (particularly the UE and the AMF) can transition to a registered state (5GMM-REGISTEDED state) based on the completion of the registration procedure. Note that each registration state may be managed by each device for each access. Specifically, each device may independently manage the registration state (registered state or deregistered state) for 3GPP access and the registration state for non-3GPP access.

Furthermore, the registration procedure may be a procedure for updating location registration information of the UE in the network and/or for periodically notifying the network of the status of the UE from the UE and/or for updating certain parameters relating to the UE in the network.

The UE may initiate the registration procedure when it performs mobility across TAs. In other words, the UE may initiate the registration procedure when it moves to a TA different from the TA indicated in the TA list it holds. Furthermore, the UE may initiate this procedure when a back-off timer or other timer that is being executed expires. Furthermore, the UE may initiate the registration procedure when it is necessary to update the context of each device due to disconnection or invalidation of a PDU session. Furthermore, the UE may initiate the registration procedure when there is a change in the capability information and/or preferences regarding the establishment of the UE's PDU session. Furthermore, the UE may initiate the registration procedure periodically. Furthermore, the UE may initiate the registration procedure based on the completion of a UE configuration update procedure, or based on the completion of a registration procedure, or based on the completion of a PDU session establishment procedure, or based on the completion of a PDU session management procedure, or based on information received from the network in each procedure, or based on the expiration or stop of a back-off timer. The UE may execute the registration procedure at any timing, not limited to these.

In addition, the procedure for the above-mentioned UE to transition from a state where it is not registered in the network to a state where it is registered may be referred to as an initial registration procedure or a registration procedure for initial registration, and the registration procedure performed when the UE is registered in the network may be referred to as a registration procedure for mobility and periodic registration update or a mobility and periodic registration procedure.

In Figure 6, new AMF indicates the AMF to which the UE is registered by this procedure, and old AMF means the AMF to which the UE was registered by a procedure prior to this procedure. If no change in AMF occurs within this procedure, the interface between the old AMF and new AMF and the procedure between the old AMF and new AMF do not occur, and the new AMF may be the same device as the old AMF. In this embodiment, when AMF is written, it may mean the new AMF, the old AMF, or both.

First, the UE starts the registration procedure by sending a registration request message to the new AMF (S600) (S602) (S604). Specifically, the UE sends an RRC message including a registration request message to the 5G AN (or gNB) (S600). The registration request message is a NAS message transmitted and received on the N1 interface. The RRC message may be a control message transmitted and received between the UE and the 5G AN (or gNB). The NAS message is processed in the NAS layer, and the RRC message is processed in the RRC layer. The NAS layer is a layer higher than the RRC layer.

Here, the UE can transmit at least one or more of the first and second identification information in the registration request message and/or the RRC message. Furthermore, the UE can transmit the registration request message and/or the RRC message including identification information indicating the type of this procedure. Here, the identification information indicating the type of this procedure can be a 5GS registration type IE, and can be information indicating that this procedure is a registration procedure for initial registration, or for updating registration information associated with movement, or for periodic updating of registration information, or for emergency registration.

The UE may include UE capability information in the registration request message to inform the network of the capabilities that the UE supports. Here, the UE capability information may be 5G MM capability of 5GS.

The UE may transmit these identification information in a different control message, for example, a control message of a layer lower than the RRC layer (for example, the MAC layer, the RLC layer, or the PDCP layer). By transmitting these identification information, the UE may indicate that the UE supports each function, may indicate a request from the UE, or may indicate both. Furthermore, when multiple identification information are transmitted and received, two or more of these identification information may be configured as one or more identification information. The information indicating support for each function and the information indicating a request to use each function may be transmitted and received as the same identification information, or may be transmitted and received as different identification information.

In addition, the UE may select and decide whether to transmit the first and second identification information to the network based on the UE's capability information, and/or UE policy, and/or UE status, and/or user registration information, and/or context held by the UE, etc.

The UE may transmit the second identification information when it has a function for managing the maximum number of UEs connected to the slice or when it requests at least one S-NSSAI that requires management for managing the maximum number of UEs connected to the slice. By transmitting the second identification information, the UE may notify the network that it has a function for storing the first NSSAI.

Furthermore, if the UE has Network Slice-Specific Authentication and Authorization (NSSAA) functionality or if the UE requests at least one S-NSSAI that identifies a slice that requires NSSAA, the UE may send the capability information in the registration request message. By sending the capability information, the UE may request the network to treat the UE as a UE with NSSAA functionality and to perform authentication and authorization procedures using the NSSAA functionality in procedures related to the UE.

The UE may store the allowed NSSAI for the requested access of the requested PLMN and/or the configured NSSAI and rejected NSSAI for the requested PLMN. Additionally, the UE may also store the mapped S-NSSAI of the S-NSSAI included in each NSSAI.

The UE may transmit the second identification information when it stores an allowed NSSAI and/or holds a configured NSSAI for the requested access of the requested PLMN. The UE may select one or more S-NSSAIs from the stored allowed NSSAIs and/or configured NSSAIs and transmit the first identification information by including them. Furthermore, when the UE stores a rejected NSSAI, the UE may transmit the S-NSSAI included in the rejected NSSAI without including it in the first identification information. Furthermore, the UE may transmit the S-NSSAI or the S-NSSAI related to the S-NSSAI without including it in the first identification information when a back-off timer associated with the S-NSSAI is valid, in other words, when the back-off timer is running or until the back-off timer is stopped. Specifically, if the S-NSSAI associated with the backoff timer is the S-NSSAI of the requesting PLMN, and if the backoff timer is valid, the S-NSSAI may be transmitted without being included in the first identification information.

Conversely, if the UE does not hold a valid S-NSSAI, it may not include a first identification in the registration request message. Furthermore, if the UE does not hold a valid S-NSSAI, it may include a first identification that does not include any S-NSSAI in the registration request message. Furthermore, if the UE does not hold a valid S-NSSAI, it may include no NSSAI in the registration request message.

Here, the valid S-NSSAI may be the S-NSSAI described above. Specifically, the valid S-NSSAI may be an S-NSSAI included in the stored allowed NSSAI and/or configured NSSAI. More specifically, the valid S-NSSAI may be an S-NSSAI included in the allowed NSSAI and/or configured NSSAI stored in the current PLMN or SNPN (Stand-alone Non-Public Network). Furthermore, the valid S-NSSAI may be an S-NSSAI that is not associated with a running back-off timer. In other words, the valid S-NSSAI may be an S-NSSAI that is not restricted by a running back-off timer in the current PLMN or SNPN (Stand-alone Non-Public Network).

Furthermore, the UE may not include an NSSAI in the registration request message. The UE may include no NSSAI in the registration request message. Furthermore, the UE may include an NSSAI that does not include any S-NSSAI in the registration request message. Here, the NSSAI that does not include any S-NSSAI may be a Requested NSSAI that does not include any S-NSSAI.

Note that when an MM message is expressed as being sent using no NSSAI, it may mean sending an MM message without including a specific NSSAI, or sending an MM message including an NSSAI that does not include any S-NSSAI, or it may mean both. Furthermore, a network that receives such an MM message may recognize that since no NSSAI and/or S-NSSAI is included, it is a request for a default S-NSSAI and/or a default network slice. Therefore, no NSSAI may be information indicating that the MM message does not include an NSSAI, and/or information indicating an NSSAI that does not include any S-NSSAI, and/or information meaning that a default network slice is requested.

The UE may include identification information other than the first and second identification information in the registration request message and/or the RRC message including the registration request message, for example, the UE ID and/or the PLMN ID and/or the AMF identification information. Here, the AMF identification information may be information that identifies an AMF or a set of AMFs, for example, 5G-S-TMSI (5G S-Temporary Mobile Subscription Identifier) or GUAMI (Globally Unique AMF Identifier).

The UE may also initiate a PDU session establishment procedure during the registration procedure by sending a registration request message including an SM message (e.g., a PDU session establishment request message) or by sending an SM message (e.g., a PDU session establishment request message) together with the registration request message.

When a 5G AN (or gNB) receives an RRC message including a registration request message, it selects an AMF to which to forward the registration request message (S602). The 5G AN (or gNB) can select an AMF based on one or more identification information included in the registration request message and/or the RRC message including the registration request message. Specifically, the 5G AN (or gNB) may select a new AMF to which to send the registration request message based on at least one of the first and second identification information.

For example, the 5G AN (or gNB) may select an AMF based on the first identification information. Specifically, the 5G AN (or gNB) may select an AMF that is included in or has connectivity to a network slice identified by an S-NSSAI included in the first identification information.

Furthermore, for example, a 5G AN (or gNB) may select, based on the second identification information, an AMF having functionality for managing the maximum number of UEs connecting to the slice and/or an AMF having connectivity to a network having functionality for managing the maximum number of UEs connecting to the slice.

Note that the method of selecting an AMF is not limited to this, and the 5G AN (or gNB) may select an AMF based on other conditions. The 5G AN (or gNB) extracts the registration request message from the received RRC message and forwards the registration request message to the selected new AMF (S604). Note that if at least one of the first and second identification information is not included in the registration request message but is included in the RRC message, the identification information included in the RRC message may be forwarded to the selected AMF together with the registration request message (S604).

The new AMF receives a registration request message. The new AMF may receive at least one of the first and second identification information together with the registration request message. The registration request message may be a message sent by the UE.

When the new AMF receives a registration request message, it can execute a first condition determination. The first condition determination is for determining whether the network (or the new AMF) accepts the UE's request. When the first condition determination is true, the new AMF executes procedures S606 to S612. On the other hand, when the first condition determination is false, the new AMF may execute the procedure S610 without executing the procedures S606 to S608.

Alternatively, the new AMF may request the UE context from the old AMF and perform the first condition determination after receiving the UE context from the old AMF (S606, S608). In that case, the new AMF executes S610 and S612 if the first condition determination is true. On the other hand, the new AMF may execute S610 if the first condition determination is false.

Here, if the first condition determination is true, the control message sent and received in S610 may be a Registration accept message, and if the first condition determination is false, the control message sent and received in S610 may be a Registration reject message.

Furthermore, the first condition determination may be performed based on the receipt of a registration request message, and/or each identification information contained in the registration request message, and/or subscriber information, and/or network capability information, and/or operator policy, and/or network status, and/or user registration information, and/or context held by the AMF, etc.

For example, if the network permits the UE's request, the first condition determination may be true, and if the network does not permit the UE's request, the first condition determination may be false. Also, if the network to which the UE is registered and/or a device within the network supports the function requested by the UE, the first condition determination may be true, and if the function requested by the UE is not supported, the first condition determination may be false. Furthermore, if the identification information to be transmitted and received is permitted, the first condition determination may be true, and if the identification information to be transmitted and received is not permitted, the first condition determination may be false.

In addition, if the S-NSSAI included in the requested NSSAI received by the AMF from the UE is information identifying a slice that requires a Network Slice specific Authentication and Authorization procedure, and if the AMF stores that the result of the Network Slice specific Authentication and Authorization procedure of the corresponding S-NSSAI for the UE is successful, the first condition determination may be true. Alternatively, if there is no S-NSSAI to allow for the UE and there are no plans to assign an Allowed NSSAI to the UE in the future, the first condition determination may be false.

In addition, if the S-NSSAI included in the requested NSSAI received by the AMF from the UE is information identifying a slice that requires management of the maximum number of UEs connected to the slice, and if the maximum number of UEs has not been reached, the first condition determination may be true. Or, even if there is no S-NSSAI permitted for the UE, if it is expected that an Allowed NSSAI will be assigned to the UE in the future, the first condition determination may be true.

When the AMF assigns a first NSSAI to the UE when the UE does not have an authorized S-NSSAI, the first condition determination may be true or false.

If the new AMF is different from the AMF indicated in the AMF identification information included in the message received from the UE, the new AMF executes the procedures of S606 and S608, and if the new AMF is the same as the AMF indicated in the AMF identification information included in the message received from the UE, the procedures of S606 and S608 are not executed. In other words, if an AMF change occurs due to this procedure, the procedures of S606 and S608 are executed, and if an AMF change does not occur, the procedures of S606 and S608 are skipped.

The UE context transfer procedure (S606, S608) is explained. The new AMF sends a UE context request message to the old AMF, with the AMF indicated in the AMF identification information as the old AMF (S606). The old AMF sends the UE context to the new AMF based on the received UE context request message. The new AMF generates a UE context based on the received UE context.

Here, the UE context transmitted from the new AMF to the old AMF may include a UE ID and an allowed NSSAI. Furthermore, the UE context may include a configured NSSAI and/or a rejected NSSAI, an NSSAI and/or a pending NSSAI, and/or a first NSSAI. Furthermore, the allowed NSSAI, and/or the configured NSSAI, and/or the rejected NSSAI, and/or the pending NSSAI, and/or the first NSSAI included in the UE context, and the S-NSSAI included in each NSSAI may be linked to information on whether notification to the UE has been completed.

The UE context may also include information on the S-NSSAI requiring a Network Slice-Specific Authentication and Authorization procedure, and/or information indicating that the Network Slice-Specific Authentication and Authorization procedure has been completed for the UE, that authentication has been successful, and/or information indicating that authentication has failed.

The UE context may also include information on S-NSSAI, which requires management of the maximum number of UEs connecting to a slice, and/or information indicating that the maximum number of UEs has been reached, and/or information indicating whether the maximum number of UEs connecting to a slice has been reached.

In addition, information regarding the characteristics of these S-NSSAIs may be managed as a single piece of information. Specifically, the network may associate and store, for each S-NSSAI, information indicating whether an NSSAA is required, whether the NSSAA was successful, whether management of the maximum number of UEs connecting to the slice is required, and whether the maximum number of UEs connecting to the slice has been reached.

The new AMF sends a control message to the UE based on the determination of the first condition determination and/or based on receiving the UE context from the old AMF (S610). The control message may be a registration accept message or a registration reject message.

The new AMF may transmit one or more tenth identification information pieces included in a control message. Alternatively, the new AMF may transmit one or more of at least the tenth to fifteenth identification information pieces included in a control message. By transmitting these identification information pieces and/or control messages, the AMF may indicate that the network supports each function, may indicate that the UE's request has been accepted, may indicate that the request from the UE has not been permitted, or may indicate a combination of these. Furthermore, when multiple identification information pieces are transmitted and received, two or more of these identification information pieces may be configured as one or more identification information pieces. The information indicating support for each function and the information indicating a request to use each function may be transmitted and received as the same identification information, or may be transmitted and received as different identification information.

The AMF may send at least one of identification information 10 to 15 when it receives at least one of identification information 1 to 2 from the UE and/or when the UE's configuration information has been updated since the last registration procedure.

When the AMF receives the first identification information and/or the second identification information from the UE, it may transmit at least one of the identification information 10 to 15 in a control message.

The AMF may further include the configured NSSAI, and/or the allowed NSSAI, and/or the rejected NSSAI, and/or the pending NSSAI in the control message and transmit it. Note that the 10th to 15th identification information may be included in the allowed NSSAI, and/or the rejected NSSAI, and/or the pending NSSAI and transmitted, or may be transmitted as information separate from these.

When the AMF sends a control message, if there is no S-NSSAI (allowed NSSAI) permitted for the UE, but an NSSAA procedure is planned to be performed after completion of this procedure or in parallel with this procedure, or if an NSSAA procedure is being performed between the UE and the network, or if a pending NSSAI was sent in the control message, the AMF may send an empty value in the allowed NSSAI.

When the AMF sends a control message, if there is no S-NSSAI (allowed NSSAI) permitted for the UE, but the 10th identification information is included in the control message, or if the first NSSAI has been notified to the UE prior to this procedure, the AMF may send an empty value in the Allowed NSSAI.

When the AMF includes the 13th identification information in the control message, indicating that it applies to all PLMNs, it may also include the 15th identification information in the control message.

Furthermore, the AMF may include one or more of the 10th to 15th identification information in the control message when it wants to start the back-off timer. In this case, the 11th identification information may indicate that the default S-NSSAI is congested. Furthermore, the 11th identification information may indicate that the UE is unable to send an MM message for no NSSAI. Furthermore, the 11th identification information may indicate that the UE is unable to send an MM message for no NSSAI because the default S-NSSAI is congested. Furthermore, the 11th identification information may indicate that no NSSAI is congested. Furthermore, the 11th identification information may indicate that the UE is unable to send an MM message for no NSSAI because no NSSAI is congested.

Furthermore, when the AMF wants to stop a running back-off timer, the AMF may also include one or more of the identification information 10 to 15 in the control message. In this case, the 11th identification information may indicate that congestion for the default S-NSSAI has been resolved. Furthermore, the 11th identification information may indicate that the UE can send an MM message for no NSSAI. Furthermore, the 11th identification information may indicate that congestion for the default S-NSSAI has been resolved, so that the UE can send an MM message for no NSSAI. Furthermore, the 11th identification information may indicate that congestion for no NSSAI has been resolved. Furthermore, the 11th identification information may indicate that congestion for no NSSAI has been resolved, so that the UE can send an MM message for no NSSAI.

Furthermore, the AMF may also include one or more of the identification information 10 to 15 in the control message when it wants to extend or shorten an ongoing back-off timer. In this case, the 11th identification information may indicate that congestion for the default S-NSSAI has not been resolved. Furthermore, the 11th identification information may indicate that the UE is unable to send an MM message for no NSSAI. Furthermore, the 11th identification information may indicate that congestion for the default S-NSSAI has not been resolved, so that the UE is unable to send an MM message for no NSSAI. Furthermore, the 11th identification information may indicate that congestion for no NSSAI has not been resolved. Furthermore, the 11th identification information may indicate that congestion for no NSSAI has not been resolved, so that the UE is unable to send an MM message for no NSSAI.

Furthermore, when it is desired to stop a running back-off timer, the AMF may not include the 12th identification information in the control message. Conversely, when it is desired to extend or shorten a running back-off timer, the AMF may include the 12th identification information indicating the new value in the control message. Furthermore, when it is desired to start a back-off timer, the AMF may include the 12th identification information.

Furthermore, the AMF may include one or more of the identification information from the tenth to fifteenth in the control message when the default S-NSSAI is congested. Furthermore, the AMF may include one or more of the identification information from the tenth to fifteenth in the control message when the UE is unable to transmit an MM message for no NSSAI. Furthermore, the AMF may include one or more of the identification information from the tenth to fifteenth in the control message when the default S-NSSAI is congested and the UE is unable to transmit an MM message for no NSSAI. Furthermore, the AMF may include one or more of the identification information from the tenth to fifteenth in the control message when the no NSSAI is congested. Furthermore, the AMF may include one or more of the identification information from the tenth to fifteenth in the control message when the no NSSAI is congested and the UE is unable to transmit an MM message for no NSSAI.

Furthermore, the AMF may include one or more of the identification information from the tenth to fifteenth in the control message when congestion for the default S-NSSAI is resolved. Furthermore, the AMF may include one or more of the identification information from the tenth to fifteenth in the control message when the UE is capable of transmitting an MM message for no NSSAI. Furthermore, the AMF may include one or more of the identification information from the tenth to fifteenth in the control message when congestion for the default S-NSSAI is resolved and the UE is capable of transmitting an MM message for no NSSAI. Furthermore, the AMF may include one or more of the identification information from the tenth to fifteenth in the control message when congestion for no NSSAI is resolved. Furthermore, the AMF may include one or more of the identification information from the tenth to fifteenth in the control message when congestion for no NSSAI is resolved and the UE is capable of transmitting an MM message for no NSSAI.

Furthermore, the AMF may include one or more of the identification information from the tenth to the fifteenth in the control message when congestion for the default S-NSSAI has not been resolved. Furthermore, the AMF may include one or more of the identification information from the tenth to the fifteenth in the control message when the UE is unable to transmit an MM message for no NSSAI. Furthermore, the AMF may include one or more of the identification information from the tenth to the fifteenth in the control message when congestion for the default S-NSSAI has not been resolved and therefore the UE is unable to transmit an MM message for no NSSAI. Furthermore, the AMF may include one or more of the identification information from the tenth to the fifteenth in the control message when congestion for no NSSAI has not been resolved. Furthermore, the AMF may include one or more of the identification information from the tenth to the fifteenth in the control message when congestion for no NSSAI has not been resolved and therefore the UE is unable to transmit an MM message for no NSSAI.

Here, the default S-NSSAI being congested may mean that the default slice is congested. More specifically, the default S-NSSAI being congested may mean that the slice identified by the default S-NSSAI is congested. Furthermore, the no NSSAI being congested may mean that the slice identified by the no NSSAI is congested.

Furthermore, the AMF may instruct the UE to start a back-off timer by transmitting one or more of the identification information from the tenth to the fifteenth. Furthermore, the AMF may indicate that the default S-NSSAI is congested by transmitting one or more of the identification information from the tenth to the fifteenth. Furthermore, the AMF may indicate that the UE is unable to transmit an MM message for no NSSAI by transmitting one or more of the identification information from the tenth to the fifteenth. Furthermore, the AMF may indicate that the UE is unable to transmit an MM message for no NSSAI because the default S-NSSAI is congested by transmitting one or more of the identification information from the tenth to the fifteenth. Furthermore, the AMF may indicate that the no NSSAI is congested by transmitting one or more of the identification information from the tenth to the fifteenth. Furthermore, the AMF may indicate that the UE is unable to transmit an MM message for no NSSAI because the no NSSAI is congested by transmitting one or more of the identification information from the tenth to the fifteenth.

Furthermore, the AMF may instruct the UE to stop a running back-off timer by transmitting one or more of the identification information from the tenth to fifteenth. Furthermore, the AMF may indicate that congestion for the default S-NSSAI has been resolved by transmitting one or more of the identification information from the tenth to fifteenth. Furthermore, the AMF may indicate that the UE can transmit an MM message for no NSSAI by transmitting one or more of the identification information from the tenth to fifteenth. Furthermore, the AMF may indicate that congestion for the default S-NSSAI has been resolved by transmitting one or more of the identification information from the tenth to fifteenth. Furthermore, the AMF may indicate that congestion for the no NSSAI has been resolved by transmitting one or more of the identification information from the tenth to fifteenth. Further, the AMF may indicate that the congestion for no NSSAI has been resolved and therefore the UE can send an MM message for no NSSAI by sending one or more of the identities 10 to 15.

Furthermore, the AMF may instruct the UE to extend or shorten an ongoing back-off timer by transmitting one or more of the identification information in the tenth to fifteenth. Furthermore, the AMF may indicate that congestion for the default S-NSSAI has not been resolved by transmitting one or more of the identification information in the tenth to fifteenth. Furthermore, the AMF may indicate that the UE is unable to transmit an MM message for no NSSAI by transmitting one or more of the identification information in the tenth to fifteenth. Furthermore, the AMF may indicate that the UE is unable to transmit an MM message for no NSSAI because congestion for the default S-NSSAI has not been resolved by transmitting one or more of the identification information in the tenth to fifteenth. Furthermore, the AMF may indicate that congestion for no NSSAI has not been resolved by transmitting one or more of the identification information in the tenth to fifteenth. Further, the AMF may indicate that the UE cannot send an MM message for no NSSAI because congestion for no NSSAI is not resolved by sending one or more identities among the 10th to 15th identities.

Furthermore, the AMF may instruct the UE to stop a running back-off timer by not including the 12th identification information. Conversely, the AMF may instruct the UE to extend or shorten a running back-off timer by including the 12th identification information indicating a new value. Furthermore, the AMF may instruct the UE to start a back-off timer by including the 12th identification information.

The above-mentioned process may be performed when the UE does not provide an NSSAI. Furthermore, the above-mentioned process may be performed when the UE provides no NSSAI. Furthermore, the above-mentioned process may be performed when the UE provides an NSSAI that does not include any S-NSSAI.

In other words, the above-mentioned processing may be performed when the registration request message does not include an NSSAI. Furthermore, the above-mentioned processing may be performed when the registration request message includes no NSSAI. Furthermore, the above-mentioned processing may be performed when the registration request message includes an NSSAI that does not include any S-NSSAI.

The UE receives the control message and/or one or more pieces of information among the 10th to 15th identification information from the network. More specifically, the UE receives the control message and/or one or more pieces of information among the 10th to 15th identification information from the new AMF.

The UE may recognize the received information based on the reception of at least one of the tenth to fifteenth identification information. Specifically, the UE may recognize that the maximum number of UEs connected per slice has been reached, and therefore transmission of MM messages and/or transmission of SM messages using the S-NSSAI indicated by the tenth identification information and/or the S-NSSAI indicated by the fourteenth identification information and/or the S-NSSAI related to the mapped S-NSSAI indicated by the fifteenth identification information is temporarily prohibited. Note that the MM procedure here may be a registration request message, and the SM message may be a PDU session establishment request message.

The UE may perform the following operations for each identification information 10 based on receiving at least one of the identification information 10 to 15 and/or receiving a control message:

The UE may include the S-NSSAI indicated by the tenth identification information and/or the S-NSSAI indicated by the fourteenth identification information and/or the S-NSSAI related to the mapped S-NSSAI indicated by the fifteenth identification information in an appropriate first NSSAI and store it. Specifically, the UE may add the S-NSSAI indicated by the received fourteenth identification information to the first NSSAI associated with the information indicated by the eleventh identification information and/or the thirteenth identification information.

Alternatively, the UE may add the mapped S-NSSAI indicated in the received 15th identification information to the first NSSAI, or may add the S-NSSAI related to the mapped S-NSSAI indicated in the received 15th identification information to the first NSSAI associated with the current PLMN, or may add it to the first NSSAI associated with the current PLMN and the current access type, or may add it to the first NSSAI(s) associated with the current PLMN and all access types.

Furthermore, if the S-NSSAI included in the first NSSAI stored by the UE is included in the allowed NSSAI stored by the UE and associated with the PLMN and access type requested by the UE in this procedure and other access types, the S-NSSAI may be deleted from the allowed NSSAI.

Furthermore, when the UE receives the 15th identification information, it may store the S-NSSAI indicated by the 15th identification information as a mapped S-NSSAI of the S-NSSAI indicated by the 14th identification information.

If the received 13th identification information indicates that it applies to all PLMNs, the UE may delete the S-NSSAI associated with the mapped S-NSSAI indicated in the 15th identification information from the allowed NSSAI corresponding to PLMNs other than the current PLMN.

Based on receiving the tenth identification information and/or the eleventh identification information and/or receiving the control message, the UE may recognize that the S-NSSAI indicated in the tenth identification information has reached the maximum number of UEs connected per slice. Here, the S-NSSAI indicated in the tenth identification information may be the S-NSSAI indicated in the fourteenth identification information and/or the mapped S-NSSAI indicated in the fifteenth identification information.

Based on receiving at least one of the 10th to 15th identification information and/or receiving a control message, the UE may start counting a back-off timer associated with the S-NSSAI or may manage the back-off timer using the received back-off timer value. Here, the back-off timer value may be the timer value indicated in the 10th identification information and/or the 12th identification information, and the S-NSSAI may be the S-NSSAI indicated in the 1st identification information and/or the 10th identification information and/or the 14th identification information and/or the mapped S-NSSAI indicated in the 15th identification information.

While the backoff timer is running, the UE may be prohibited from sending MM messages or SM messages using the S-NSSAI associated with the backoff timer, or the mapped S-NSSAI associated with the backoff timer, or the S-NSSAI related to the mapped S-NSSAI associated with the backoff timer.

Furthermore, when the UE receives the 13th identification information, it may adapt the back-off timer according to the validity range indicated in the 13th identification information.

Specifically, if the 13th identification information is information indicating that the back-off timer is adapted within the current PLMN, the UE may adapt the back-off timer within the current PLMN. Specifically, upon a PLMN change, the UE may not stop counting the back-off timer or the back-off timer, but the restriction imposed by the back-off timer associated with the PLMN before the move may be lifted. In other words, when the PLMN is changed, the UE maintains the back-off timer, but the restriction on the PLMN before the move may be lifted.

Alternatively, the UE may stop the count of the back-off timer associated with the current PLMN or the back-off timer when the PLMN is changed. In other words, the UE may stop the back-off timer when the PLMN is changed, and the restriction on the PLMN before the movement may be lifted.

Alternatively, if the 13th identification information is information indicating that the back-off timer applies to all PLMNs, the UE may apply the back-off timer to all PLMNs. In other words, the UE may maintain the back-off timer without stopping it even if a PLMN change occurs. If a PLMN change occurs while the back-off timer is running, the UE may maintain a state in which MM messages and SM messages are prohibited using the S-NSSAI of the destination PLMN associated with the mapped S-NSSAI of the S-NSSAI to which the back-off timer was associated, or the S-NSSAI of the destination PLMN related to the mapped S-NSSAI, or the mapped S-NSSAI.

Alternatively, if the 13th identification information indicates that the back-off timer is applied in the current registration area, the UE may apply the back-off timer in the current registration area. In other words, when the UE leaves the registration area, the UE may stop counting the back-off timer or stop the back-off timer.

Further, the UE may manage and/or store a first NSSAI associated with the 11th identity and/or the 13th identity.

Here, when the back-off timer stops or expires, the restriction is lifted, and the UE may transition to a state in which it can transmit an MM message or an SM message using the S-NSSAI to which the back-off timer was associated, and/or the S-NSSAI related to the mapped S-NSSAI to which the back-off timer was associated, and/or the mapped S-NSSAI to which the back-off timer was associated. In other words, when the back-off timer stops or expires, the UE may transition to a state in which it can transmit an MM message using the S-NSSAI to which the back-off timer was associated, and/or the S-NSSAI related to the mapped S-NSSAI to which the back-off timer was associated, and/or the mapped S-NSSAI to which the back-off timer was associated as the Requested NSSAI.

Furthermore, the UE may transition to a state in which it can transmit an MM message using the NSSAI associated with the back-off timer when the back-off timer stops or expires. In other words, the UE may transition to a state in which it can transmit an MM message using the NSSAI associated with the back-off timer as the Requested NSSAI when the back-off timer stops or expires.

Furthermore, upon stopping or expiration of the back-off timer, the UE may delete from the first NSSAI the S-NSSAI to which the back-off timer was associated, or the mapped S-NSSAI to which the back-off timer was associated, or the S-NSSAI related to the mapped S-NSSAI to which the back-off timer was associated.

Furthermore, the UE may start a back-off timer based on receipt of a control message and/or one or more of the 10th to 15th identification information. Furthermore, the UE may set a 12th identification information to a timer value of the back-off timer based on receipt of a control message and/or one or more of the 10th to 15th identification information. In other words, the UE may start a back-off timer with a value indicated by the 12th identification information based on receipt of a control message and/or one or more of the 10th to 15th identification information.

Furthermore, the UE may associate no NSSAI with the back-off timer if it has not provided an NSSAI to the network. Further, the UE may associate no NSSAI with the back-off timer if it has provided no NSSAI to the network. Further, the UE may associate no NSSAI with the back-off timer if it has provided an NSSAI to the network that does not include any S-NSSAI.

Furthermore, if an NSSAI was not provided by the UE together with the registration request message, the back-off timer may be associated with no NSSAI. In other words, if an NSSAI was not provided by the UE together with the registration request message, the NSSAI associated with the back-off timer may be no NSSAI. In yet another words, if an NSSAI was not provided by the UE together with the registration request message, the UE may associate the back-off timer with no NSSAI.

Furthermore, if no NSSAI is provided by the UE together with the registration request message, the back-off timer may be associated with no NSSAI. In other words, if no NSSAI is provided by the UE together with the registration request message, the NSSAI associated with the back-off timer may be no NSSAI. In yet another words, if no NSSAI is provided by the UE together with the registration request message, the UE may associate the back-off timer with no NSSAI.

Furthermore, if an NSSAI that does not include any S-NSSAI is provided by the UE together with the registration request message, the back-off timer may be associated with no NSSAI. In other words, if an NSSAI that does not include any S-NSSAI is provided by the UE together with the registration request message, the NSSAI associated with the back-off timer may be no NSSAI. In yet another words, if an NSSAI that does not include any S-NSSAI is provided by the UE together with the registration request message, the UE may associate the back-off timer with no NSSAI.

Furthermore, even if the UE does not provide an NSSAI and/or provides no NSSAI and/or provides an NSSAI that does not include any S-NSSAI with the registration request message, the back-off timer may be associated with the NSSAI and/or S-NSSAI received from the network. In other words, even if the UE does not provide an NSSAI and/or provides no NSSAI and/or provides an NSSAI that does not include any S-NSSAI with the registration request message, the NSSAI associated with the back-off timer may be the NSSAI and/or S-NSSAI received from the network. In other words, even if the UE does not provide an NSSAI and/or provides no NSSAI and/or provides an NSSAI that does not include any S-NSSAI with the registration request message, the UE may associate the back-off timer with the NSSAI and/or S-NSSAI received from the network.

The UE may also perform the above behavior based on receiving a control message and/or one or more of the identification information 10 to 15.

Furthermore, while a back-off timer associated with no NSSAI is running, the UE may be prohibited or not allowed to send an MM request message that does not use an NSSAI. Furthermore, while a back-off timer associated with no NSSAI is running, the UE may be prohibited or not allowed to send an MM request message that uses no NSSAI. Furthermore, while a back-off timer associated with no NSSAI is running, the UE may be prohibited or not allowed to send an MM request message that uses an NSSAI that does not include at least one S-NSSAI.

Conversely, even if the back-off timer associated with no NSSAI is running, the UE may be able or permitted to send an MM request message using a specific NSSAI and/or S-NSSAI. Note that the specific NSSAI may be an NSSAI that includes one or more S-NSSAIs.

Furthermore, while a back-off timer associated with no NSSAI is running, the UE may be prohibited from sending an MM request message that does not include an NSSAI. Furthermore, while a back-off timer associated with no NSSAI is running, the UE may be prohibited from sending an MM request message that includes no NSSAI. Furthermore, while a back-off timer associated with no NSSAI is running, the UE may be prohibited from sending an MM request message that includes an NSSAI that does not include at least one S-NSSAI.

Furthermore, while a back-off timer associated with no NSSAI and a specific NSSAI and/or S-NSSAI is running, the UE may be prohibited or not permitted to transmit an MM request message without an NSSAI and/or an MM request message using a specific NSSAI and/or S-NSSAI. Furthermore, while a back-off timer associated with no NSSAI and a specific NSSAI and/or S-NSSAI is running, the UE may be prohibited or not permitted to transmit an MM request message using no NSSAI and/or an MM request message using a specific NSSAI and/or S-NSSAI. Furthermore, while a back-off timer associated with no NSSAI and a specific NSSAI and/or S-NSSAI is running, the UE may be prohibited or not permitted to transmit an MM request message using an NSSAI that does not include any S-NSSAI and/or an MM request message using a specific NSSAI and/or S-NSSAI.

Here, the UE's transmission of an MM request message without an NSSAI may mean that the UE transmits an MM request message that does not include an NSSAI. Furthermore, the UE's transmission of an MM request message with no NSSAI may mean that the UE transmits an MM request message that includes no NSSAI. Furthermore, the UE's transmission of an MM request message with an NSSAI that does not include any S-NSSAI may mean that the UE transmits an MM request message that includes an NSSAI that does not include any S-NSSAI. Furthermore, the UE's transmission of an MM request message with a specific NSSAI and/or S-NSSAI may mean that the UE transmits an MM request message that includes a specific NSSAI and/or S-NSSAI. Furthermore, the MM request message may be a registration request message and/or a service request message, and may be an MM message.

Furthermore, when the network wants to stop a back-off timer running on the UE, the UE may receive a control message that does not include the 12th identification. Conversely, when the network wants to extend or shorten a back-off timer running on the UE, the UE may receive a control message that includes the 12th identification indicating the new value. Furthermore, when the network wants to start the UE's back-off timer, the UE may receive a control message that includes the 12th identification.

Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth identification information when the default S-NSSAI is congested. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth identification information when an MM message for no NSSAI cannot be transmitted. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth identification information when an MM message for no NSSAI cannot be transmitted because the default S-NSSAI is congested. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth identification information when the no NSSAI is congested. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth identification information when an MM message for no NSSAI cannot be transmitted because the no NSSAI is congested.

Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth when congestion for the default S-NSSAI is resolved. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth when an MM message for no NSSAI can be transmitted. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth when congestion for the default S-NSSAI is resolved and therefore an MM message for no NSSAI can be transmitted. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth when congestion for no NSSAI is resolved. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth when congestion for no NSSAI is resolved and therefore an MM message for no NSSAI can be transmitted.

Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth when congestion for the default S-NSSAI has not been resolved. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth when an MM message for no NSSAI cannot be transmitted. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth when an MM message for no NSSAI cannot be transmitted because congestion for the default S-NSSAI has not been resolved. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth when congestion for no NSSAI has not been resolved. Furthermore, the UE may receive one or more of the identification information from the tenth to fifteenth when an MM message for no NSSAI cannot be transmitted because congestion for no NSSAI has not been resolved.

Furthermore, the UE may start a back-off timer by receiving one or more of the identification information from the tenth to fifteenth. The UE may further authenticate that the default S-NSSAI is congested by receiving one or more of the identification information from the tenth to fifteenth. The UE may further authenticate that an MM message for no NSSAI cannot be transmitted by receiving one or more of the identification information from the tenth to fifteenth. The UE may further authenticate that an MM message for no NSSAI cannot be transmitted because the default S-NSSAI is congested by receiving one or more of the identification information from the tenth to fifteenth. The UE may further authenticate that no NSSAI is congested by receiving one or more of the identification information from the tenth to fifteenth. The UE may further authenticate that an MM message for no NSSAI cannot be transmitted because the no NSSAI is congested by receiving one or more of the identification information from the tenth to fifteenth.

Furthermore, the UE may stop a running back-off timer by receiving one or more of the tenth to fifteenth identification information. Furthermore, the UE may authenticate that congestion for the default S-NSSAI has been resolved by receiving one or more of the tenth to fifteenth identification information. Furthermore, the UE may authenticate that an MM message for no NSSAI can be transmitted by receiving one or more of the tenth to fifteenth identification information. Furthermore, the UE may authenticate that congestion for the default S-NSSAI has been resolved by receiving one or more of the tenth to fifteenth identification information. Furthermore, the UE may authenticate that congestion for no NSSAI has been resolved by receiving one or more of the tenth to fifteenth identification information. Furthermore, the UE may authenticate that congestion for no NSSAI has been resolved by receiving one or more of the tenth to fifteenth identification information. Furthermore, the UE may authenticate that congestion for no NSSAI has been resolved by receiving one or more of the tenth to fifteenth identification information.

Furthermore, the UE may extend or shorten an active back-off timer by receiving one or more of the identification information from the tenth to fifteenth. Furthermore, the UE may verify that congestion for the default S-NSSAI has not been resolved by receiving one or more of the identification information from the tenth to fifteenth. Furthermore, the UE may verify that an MM message for no NSSAI cannot be transmitted by receiving one or more of the identification information from the tenth to fifteenth. Furthermore, the UE may verify that congestion for the default S-NSSAI has not been resolved by receiving one or more of the identification information from the tenth to fifteenth. Furthermore, the UE may verify that congestion for no NSSAI has not been resolved by receiving one or more of the identification information from the tenth to fifteenth. Furthermore, the UE may verify that congestion for no NSSAI has not been resolved by receiving one or more of the identification information from the tenth to fifteenth.

Furthermore, the UE may stop a running back-off timer by receiving a control message that does not include the 12th identification. Conversely, the UE may extend or shorten a running back-off timer by receiving a control message that includes the 12th identification indicating a new value. Furthermore, the UE may start a back-off timer by receiving a control message that includes the 12th identification.

In addition, each process that the UE performs based on receiving each identification information as shown above may be performed during this procedure or after completion of this procedure, or may be performed after completion of this procedure based on the completion of this procedure.

Furthermore, the AMF may select and determine which of the identification information 10 to 15 to include in the control message based on each received identification information, and/or subscriber information, and/or network capability information, and/or operator policy, and/or network status, and/or user registration information, and/or context held by the AMF, etc.

Furthermore, when the control message is a registration acceptance message, the AMF can either include an SM message (e.g., a PDU session establishment acceptance message) in the registration acceptance message and send it, or send an SM message (e.g., a PDU session establishment acceptance message) together with the registration acceptance message. However, this transmission method may also be performed when an SM message (e.g., a PDU session establishment request message) is included in the registration request message. Also, this transmission method may be performed when an SM message (e.g., a PDU session establishment request message) is sent together with the registration request message. By performing such a transmission method, the AMF can indicate that the procedure for SM has been accepted in the registration procedure.

In addition, the AMF may indicate that the UE's request has been accepted by sending a registration acceptance message based on the received identification information, and/or subscriber information, and/or network capability information, and/or operator policy, and/or network status, and/or user registration information, and/or context held by the AMF, etc., or may indicate that the UE's request has been rejected by sending a registration rejection message.

The UE receives a control message via the 5G AN (gNB) (S608). If the control message is a registration acceptance message, the UE can recognize, by receiving the registration acceptance message, that the UE's request via the registration request message has been accepted, and the contents of the various identification information included in the registration acceptance message. Alternatively, if the control message is a registration rejection message, the UE can recognize, by receiving the registration rejection message, that the UE's request via the registration request message has been rejected, and the contents of the various identification information included in the registration rejection message. Furthermore, if the UE does not receive a control message even after a predetermined period has elapsed after sending the registration request message, the UE may recognize that the UE's request has been rejected.

If the control message is a registration acceptance message, the UE can further transmit a registration completion message to the AMF via the 5G AN (gNB) as a response message to the registration acceptance message (S610). When the UE receives an SM message such as a PDU session establishment acceptance message, the UE may transmit an SM message such as a PDU session establishment completion message including the registration completion message, or may indicate that the procedure for SM has been completed by including the SM message. Here, the registration completion message is a NAS message transmitted and received on the N1 interface, but is transmitted and received between the UE and the 5G AN (gNB) included in an RRC message.

The AMF receives a registration completion message via the 5G AN (gNB) (S612). Each device also completes this procedure based on the sending and receiving of a registration acceptance message and/or a registration completion message.

Alternatively, each device may complete the registration procedure based on sending or receiving a registration rejection message.

Each device may transition to or maintain a state in which the UE is registered in the network (RM#REGISTERED state or 5GMM-REGISTERED state) based on the transmission and reception of a registration acceptance message and/or a registration completion message, or may transition to or maintain a state in which the UE is not registered in the network on the access on which the registration rejection message was received for the current PLMN (RM#DEREGISTERED state or 5GMM-DEREGISTERED state) based on the transmission and reception of a registration rejection message. Furthermore, the transition of each device to each state may be based on the transmission and reception of a registration completion message or the completion of the registration procedure.

Furthermore, each device may perform processing based on the information transmitted and received in the registration procedure based on the completion of the registration procedure. For example, when transmitting and receiving information indicating that some of the UE's requests have been rejected, the device may recognize the reason why the UE's requests were rejected. Furthermore, each device may perform this procedure again based on the reason why the UE's request was rejected, or may perform the registration procedure for core network #A or another cell.

Further, the UE may store the identification information received with the registration accept message and/or the registration reject message and may recognize the network's decision based on completion of the registration procedure.

Furthermore, each device may initiate the registration procedure again upon expiration or stopping of the backoff timer.

4. EMBODIMENTS OF THE PRESENT ART
An embodiment of the present invention may be a combination of one or more of the procedures described in Section 3. For example, in the embodiment described in Section 3, after the initial registration procedure is completed, one or more of the mobility and periodic registration procedures may be performed.

Specifically, after the initial registration procedure is completed, the UE may transmit an MM message or an SM message using an S-NSSAI associated with the back-off timer based on the expiration or stopping of the back-off timer. Note that one or more MM procedures and SM procedures may be executed before, after, or in parallel with the completion of the initial registration procedure.

5. Variations
The program that runs on the device according to the present invention may be a program that controls a Central Processing Unit (CPU) or the like to make a computer function so as to realize the functions of the embodiments according to the present invention. The program or information handled by the program is temporarily stored in a volatile memory such as a Random Access Memory (RAM), a non-volatile memory such as a flash memory, a Hard Disk Drive (HDD), or other storage device system.

A program for realizing the functions of the embodiments of the present invention may be recorded on a computer-readable recording medium. The program recorded on the recording medium may be read into a computer system and executed to realize the functions. The "computer system" here refers to a computer system built into a device, and includes hardware such as an operating system and peripheral devices. Furthermore, the "computer-readable recording medium" may be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a medium that dynamically holds a program for a short period of time, or any other recording medium that is readable by a computer.

In addition, each functional block or feature of the device used in the above-mentioned embodiment may be implemented or performed by an electric circuit, for example, an integrated circuit or multiple integrated circuits. The electric circuit designed to perform the functions described herein may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or a combination thereof. The general-purpose processor may be a microprocessor, or a conventional processor, controller, microcontroller, or state machine. The electric circuit may be composed of digital circuits or analog circuits. In addition, if a technology for integrated circuitization that replaces current integrated circuits emerges due to advances in semiconductor technology, one or more aspects of the present invention may use a new integrated circuit based on that technology.

Note that the present invention is not limited to the above-mentioned embodiment. In the embodiment, one example of a device is described, but the present invention is not limited to this and can be applied to terminal devices or communication devices such as stationary or non-movable electronic devices installed indoors or outdoors, for example, AV equipment, kitchen equipment, cleaning/washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design modifications and the like that do not depart from the gist of the present invention are also included. Furthermore, the present invention can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Also included are configurations in which elements described in the above embodiments are substituted for elements that have the same effect.

1 Mobile communication systems
10 UE#A
30 PGW-U
32 PGW-C
35 SGW
40 MME
45 eNB
50 HSS
60 PCRF
80 Access Network #A (E-UTRAN)
90 Core Network #A
120 Access Network #B (5G AN)
122 gNB
130 UPF
132 SMF
140 AMF
150 UDM
160 PCF
190 Core Network #B

Claims (4)

A UE (User Equipment),
In the registration procedure, the UE
a transmitting/receiving unit that receives the first information and the second information from the control device;
When NSSAI (Network Slice Selection Assistance Information) is not provided to the control device, based on reception of first information and second information,
Associate no NSSAI with the backoff timer,
starting the back-off timer with a value indicated by the second information;
A control unit.
the first information is a reason value indicating that connection to the slice is restricted;
the second information is information indicating a value of a back-off timer,
The UE is not permitted to transmit a registration request message that does not include an NSSAI while the back-off timer is running.
The UE is characterized by: The UE is permitted to transmit a registration request message including a first NSSAI even while the back-off timer is running,
The first NSSAI includes one or more S-NSSAIs (Single Network Slice Selection Assistance Information),
The UE according to claim 1, A control device,
The control device, in the registration procedure,
A registration request message not including NSSAI (Network Slice Selection Assistance Information) is received from a UE (User Equipment),
Sending a control message to the UE;
A transmitter/receiver unit;
A control unit that includes first information and second information in the control message when a default slice is congested;
The control device instructs the UE to start a back-off timer by transmitting the control message;
the first information is a reason value indicating that connection to the slice is restricted;
the second information is information indicating a value of a back-off timer,
While the back-off timer is running, transmission of a registration request message that does not include an NSSAI of the UE is not permitted.
A control device comprising: A communication control method for UE (User Equipment),
receiving first information and second information from a control device;
When NSSAI (Network Slice Selection Assistance Information) is not provided to the control device, based on reception of first information and second information,
Associate no NSSAI with the backoff timer,
starting the back-off timer with a value indicated by the second information;
Steps
the first information is a reason value indicating that connection to the slice is restricted;
the second information is information indicating a value of a back-off timer,
The UE is not permitted to transmit a registration request message that does not include an NSSAI while the back-off timer is running.
A UE communication control method comprising:

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