UE(User Equipment)

Abstract

To clarify detailed actions related to network slice access control considering interworking between a 5GS (5G System) or a 5GC (5G Core Network) and EPC (Evolved Packet Core), which is a 4G system core network.SOLUTION: Provided is a UE that comprises a transmission / reception unit and a control unit. When the transmission / reception unit receives from a base station device a registration acceptance message or a registration refusal message including a cause value indicating a fact that a maximum UE number per network slice has been exceeded, the control unit sets a 5GS update state to "5U3 ROAMING NOT ALLOWED," deletes all 5G-GUTIs (Globally Unique Temporary Identifiers) and a TAI (Tracking Area Identity) list, and resets a registration attempt counter.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to UE (User Equipment). [Background technology]

[0002] The 3GPP (3rd Generation Partnership Project) is studying the system architecture of the 5G System (5GS), a fifth-generation (5G) mobile communication system, and is discussing how to support new procedures and new functions (see Non-Patent Documents 1 and 2). The initial release of the 5G standard, Release 15, introduced the concept of network slicing, and in Release 17, functional extensions of network slicing are being discussed (see Non-Patent Document 3). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] 3GPP TS 23.501 V17.0.0 (2021-03); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System architecture for the 5G System (5GS); Stage 2 (Release 17) [Non-patent document 2] 3GPP TS 23.502 V17.0.0 (2021-03); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Procedures for the 5G System (5GS); Stage 2 (Release 17) [Non-patent document 3] 3GPP TR 23.700-40 V17.0.0 (2021-03); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Study on Enhancement of Network Slicing Phase 2 (Release 17) Summary of the Invention [Problem to be solved by the invention]

[0004] Non-patent document 3 does not disclose detailed operations regarding network slice access control that take into account interworking between 5GS or 5GC (5G Core Network) and EPC (Evolved Packet Core), which is the core network of the 4G system.

[0005] One aspect of the present invention has been made in consideration of the above circumstances, and aims to clarify detailed operations related to network slice access control taking into account interworking between 5GS or 5GC and EPC, which is the core network of the 4G system. [Means for solving the problem]

[0006] A UE of one embodiment of the present invention is a UE (User Equipment) having a transceiver unit and a control unit, and is characterized in that when the transceiver unit receives a registration acceptance message or a registration rejection message from a base station device, the registration acceptance message includes a reason value indicating that the maximum number of UEs per network slice has been exceeded, the control unit sets the 5GS update status to 5U3 ROAMING NOT ALLOWED, deletes all 5G-GUTI and TAI lists, and resets a registration attempt counter. [Effects of the Invention]

[0007] According to the present invention, it is possible to clarify detailed operations related to network slice access control taking into account interworking between 5GS or 5GC and EPC, which is the core network of the 4G system. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an outline of a mobile communication system (EPS / 5GS). [Figure 2] FIG. 1 is a diagram illustrating the detailed configuration of a mobile communication system (EPS / 5GS). [Figure 3] FIG. 1 is a diagram illustrating the device configuration of a UE. [Figure 4] A diagram explaining the configuration of an access network device (gNB) in 5GS. [Figure 5] A diagram explaining the configuration of core network devices (AMF / SMF / UPF) in 5GS. [Figure 6] FIG. 10 is a diagram illustrating a registration procedure. [Figure 7] A diagram explaining the PDU session establishment procedure. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below 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.

[0010] [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.

[0011] FIG. 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.

[0012] In the following, these devices and functions may be referred to by abbreviating the symbols, such as UE, access network_A, core network_A, PDN, access network_B, core network_B, DN, etc.

[0013] 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, and N3IWF170, as well as interfaces that connect these devices and functions to each other.

[0014] 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.

[0015] The 4G system EPS (Evolved Packet System) includes 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) includes a UE, an access network _B, and a core network _B, but may further include a DN.

[0016] A UE is a device that can connect to a network service via 3GPP access (also referred to as a 3GPP access network, or 3GPP AN) and / or non-3GPP access (also referred to as a non-3GPP access network, or non-3GPP AN). A UE may be a terminal device capable of wireless communication, such as a mobile phone or a smartphone, and may be a terminal device that can connect to both EPS and 5GS. A UE may include a UICC (Universal Integrated Circuit Card) or an eUICC (Embedded UICC). Note that a UE may be referred to as a user device or a terminal device.

[0017] Furthermore, 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 Bs) 45 are deployed in the E-UTRAN. Note that, hereinafter, the eNB 45 may be referred to by abbreviating the symbol eNB. If there are multiple eNBs, the eNBs are connected to each other, for example, via an X2 interface. Furthermore, one or more access points are deployed in the wireless LAN access network.

[0018] Furthermore, 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 deployed in the NG-RAN. Note that, hereinafter, the symbol for gNB 122 may be abbreviated, such as gNB. The gNB is a node that provides the NR (New Radio) user plane and control plane to UEs and 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 different functions from the base station device (eNB) used in the 4G system EPS. Furthermore, when there are multiple gNBs, the gNBs are connected to each other, for example, via an Xn interface.

[0019] Furthermore, 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 specified by 3GPP, and may include a trusted non-3GPP access point (TNAP) and a trusted non-3GPP gateway function (TNGF).

[0020] In the following, E-UTRAN and NG-RAN may be referred to as 3GPP access. Also, wireless LAN access networks and non-3GPP AN may be referred to as non-3GPP access. Also, nodes located in access network_B may be collectively referred to as NG-RAN nodes.

[0021] Furthermore, 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.

[0022] The core network_A corresponds to an EPC (Evolved Packet Core), which includes, for example, an MME (Mobility Management Entity), an SGW (Serving Gateway), a PGW (Packet Data Network Gateway)-U, a PGW-C, a PCRF (Policy and Charging Rules Function), and an HSS (Home Subscriber Server).

[0023] Furthermore, the core network_B corresponds to a 5G Core Network (5GCN). In the 5GCN, for example, an Access and Mobility Management Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), a Policy Control Function (PCF), a Unified Data Management (UDM), etc. are arranged. Here, the 5GCN may be expressed as a 5GC.

[0024] 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, core network devices, or devices within the core network.

[0025] The core network (core network _A and / or core network _B) may be an IP mobile communication network operated by a mobile network operator (MNO) that connects the access network (access network _A and / or access network _B) to the PDN and / or DN, or it may be a core network for a mobile network operator that operates and manages the mobile communication system 1, or it may be a core network for a virtual mobile communication operator or virtual mobile communication service provider such as an MVNO (Mobile Virtual Network Operator) or MVNE (Mobile Virtual Network Enabler).

[0026] Also, while FIG. 1 illustrates 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 mean connecting to a communication terminal or a server device located in the PDN. Furthermore, transmitting and receiving user data to and from the PDN may mean transmitting and receiving user data to and from a communication terminal or a server device located in the PDN. The PDN may be referred to as the DN, and the DN may be referred to as the PDN.

[0027] In addition, hereinafter, at least a portion of the access network _A, the core network _A, the PDN, the access network _B, the core network _B, and the DN, and / or one or more devices included therein may be referred to as a network or a network device. In other words, when a network and / or a network device sends or receives a message and / or performs a procedure, it means that at least a portion of the access network _A, the core network _A, the PDN, the access network _B, the core network _B, and the DN, and / or one or more devices included therein send or receive a message and / or perform a procedure.

[0028] 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 transmit and receive (communicate) user data with the PDN or DN. When transmitting and receiving user data, not only IP (Internet Protocol) communication but also non-IP communication can be used.

[0029] Here, IP communication refers to data communication using IP, and data is transmitted and received using IP packets. An IP packet consists of an IP header and a payload. The payload may include data transmitted and received by devices and functions included in EPS or devices and functions included in 5GS. Non-IP communication refers to data communication that does not use IP, and data is transmitted and received in a format different from the IP packet structure. For example, non-IP communication may be data communication achieved by transmitting and receiving application data without an IP header, or it may be user data transmitted and received by a UE with a different header, such as a MAC header or an Ethernet (registered trademark) frame header, added.

[0030] 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 Fig. 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).

[0031] Here, the AUSF is a core network device having an authentication function for 3GPP access and non-3GPP access, specifically, a network function unit that receives an authentication request for 3GPP access and / or non-3GPP access from a UE and executes the authentication procedure.

[0032] 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 the 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.

[0033] 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.

[0034] [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, as logical (virtual) hardware configured on general-purpose hardware, or 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.

[0035] Note that each memory unit (memory unit_A340, memory unit_A440, memory unit_B540, memory unit_A640, memory unit_B740) in each device / function mentioned below is configured with, for example, a semiconductor memory, a solid state drive (SSD), a hard disk drive (HDD), etc. Furthermore, each memory 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 (e.g., UE, and / or access network device, and / or core network device, and / or PDN, and / or DN). Furthermore, each memory unit can store identification information, control information, flags, parameters, etc. included in control messages transmitted and received in various communication procedures described below. Furthermore, each memory unit may store this information for each UE. Furthermore, when interworking between 5GS and EPS is performed, each memory unit can store control messages and user data transmitted and received between 5GS and / or devices / functions included in EPS. At this time, not only those transmitted and received via the N26 interface but also those transmitted and received without going through the N26 interface can be stored.

[0036] [2.1. UE Device Configuration] First, an example of the device configuration of UE (User Equipment) will be explained using Figure 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.

[0037] The control unit _A300 is a functional unit that controls the operation and functions of the entire UE.The control unit _A300 realizes various processing in the UE by reading and executing various programs stored in the memory unit _A340 as necessary.

[0038] The transceiver unit _A320 is a functional unit for wireless communication 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.

[0039] Explaining in detail with reference to Figure 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.

[0040] The memory unit _A340 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the UE.

[0041] [2.2. gNB device configuration] Next, an example of the gNB device configuration will be described using Figure 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.

[0042] 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.

[0043] The network connection unit _B520 is a functional unit for 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.

[0044] 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 to and from the UE using the transceiver unit _B530.

[0045] 2, a gNB in ​​a 5G AN can communicate with an AMF via an N2 interface by using a network connection unit _B 520, and can communicate with a UPF via an N3 interface, and can communicate with a UE by using a transceiver unit _B 530.

[0046] The memory unit _B540 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the gNB.

[0047] [2.3. AMF device configuration] Next, an example of the AMF device configuration will be explained using Figure 5. The AMF is composed of a control unit _B700, a network connection unit _B720, and a memory unit _B740. The control unit _B700, the network connection unit _B720, and the memory unit _B740 are connected via a bus. The AMF may be a node that handles the control plane.

[0048] The control unit _B700 is a functional unit that controls the operation and functions of the entire AMF.The control unit _B700 realizes various processing in the AMF by reading and executing various programs stored in the memory unit _B740 as necessary.

[0049] The network connection unit _B720 is a functional unit for the AMF to connect to a base station device (gNB), and / or SMF, and / or PCF, and / or UDM, and / or SCEF in a 5G AN. In other words, the AMF can use the network connection unit _B720 to send and receive user data and / or control information between a base station device (gNB), and / or SMF, and / or PCF, and / or UDM, and / or SCEF in a 5G AN.

[0050] Explaining in detail with reference to FIG. 2, the AMF in the 5GCN can communicate with a gNB via the N2 interface by using the network connection unit _A620, can communicate with a UDM via the N8 interface, can communicate with an SMF via the N11 interface, and can communicate with a PCF via the N15 interface. The AMF can also send and receive NAS messages with a UE via the N1 interface by using the network connection unit _A620. However, since the N1 interface is logical, communication between the UE and the AMF is actually performed via a 5G AN. Furthermore, if the AMF supports the N26 interface, it can communicate with an MME via the N26 interface by using the network connection unit _A620.

[0051] The memory unit _B740 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the AMF.

[0052] 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), supporting the N2 interface for the N3IWF (Non-3GPP Interworking Function), supporting the transmission and reception of NAS signals with the UE via the N3IWF, and authenticating the UE connected via the N3IWF.

[0053] In addition, registration management manages the RM state for each UE. The RM state may be synchronized between the UE and the AMF. The RM state includes an unregistered state (RM-DEREGISTERED state) and a registered state (RM-REGISTERED state). In the RM-DEREGISTERED state, the UE is not registered with 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 with the network, and therefore the UE can receive services that require registration with the network. Note that the RM state may also 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.

[0054] In other words, 5GMM-REGISTERED may be a state in which each device has established a 5GMM context or a PDU session context. When each device is 5GMM-REGISTERED, UE_A10 may start transmitting and receiving user data and control messages, or may respond to paging. Furthermore, when each device is 5GMM-REGISTERED, UE_A10 may perform registration procedures other than the registration procedure for initial registration, and / or service request procedures.

[0055] Furthermore, 5GMM-DEREGISTERED may be a state in which each device has not established a 5GMM context, a state in which UE_A10's location information is not known to the network, or a state in which UE_A10 is unreachable from the network. Note that when each device is 5GMM-DEREGISTERED, UE_A10 may initiate a registration procedure or may establish a 5GMM context by performing the registration procedure.

[0056] In addition, connection management manages the CM state for each UE. 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 or an N3 interface 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 and / or an N3 interface connection.

[0057] 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 include 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 include 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). Note that the non-connected state may be expressed as an idle mode, and the connected state mode may be expressed as a connected mode.

[0058] The CM state may be expressed as a 5GMM mode. In this case, the unconnected state may be expressed as a 5GMM-IDLE mode, and the connected state may be expressed as a 5GMM-CONNECTED mode. Furthermore, the unconnected state in 3GPP access may be expressed as a 5GMM-IDLE mode over 3GPP access, and the connected state in 3GPP access may be expressed as a 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.

[0059] In addition, one or more AMFs may be placed in the core network_B. In addition, the AMF may be a Network Function (NF) that manages one or more Network Slice Instances (NSIs). In addition, the AMF may be a Common Control Plane Network Function (CCNF) shared among multiple NSIs.

[0060] In addition, the N3IWF is a device and / or function located between the non-3GPP access and the 5GCN when the UE connects to the 5GS via the non-3GPP access.

[0061] [2.4. SMF device configuration] Next, an example of the SMF device configuration will be explained using Figure 5. The SMF is composed of a control unit _B700, a network connection unit _B720, and a memory unit _B740. The control unit _B700, the network connection unit _B720, and the memory unit _B740 are connected via a bus. The SMF may be a node that handles the control plane.

[0062] The control unit _B700 is a functional unit that controls the operation and functions of the entire SMF.The control unit _B700 realizes various processing in the SMF by reading and executing various programs stored in the memory unit _B740 as necessary.

[0063] The network connection unit _B720 is a functional unit for the SMF to connect with the AMF, and / or UPF, and / or PCF, and / or UDM. In other words, the SMF can send and receive user data and / or control information between the AMF, and / or UPF, and / or PCF, and / or UDM using the network connection unit _B720.

[0064] Explaining in more detail with reference to Figure 2, the SMF in the 5GCN can communicate with the AMF via the N11 interface, with the UPF via the N4 interface, with the PCF via the N7 interface, and with the UDM via the N10 interface by using the network connection unit _A620.

[0065] The memory unit _B740 is a functional unit for storing programs, user data, control information, etc. required for each operation of the SMF.

[0066] The SMF has session management functions such as establishing, modifying, and releasing PDU sessions, IP address allocation for UEs and its management, UPF selection and control, UPF configuration for routing traffic to the appropriate destination, sending and receiving the SM portion of NAS messages, Downlink Data Notification, providing AN-specific (for each AN) SM information to be sent to the AN via the N2 interface via the AMF, determining the SSC mode (Session and Service Continuity mode) for the session, and roaming functions.

[0067] [2.5. UPF device configuration] Next, an example of the device configuration of the UPF will be explained using Figure 5. The UPF is composed of a control unit _B700, a network connection unit _B720, and a memory unit _B740. The control unit _B700, the network connection unit _B720, and the memory unit _B740 are connected via a bus. The UPF may be a node that handles the control plane.

[0068] The control unit _B700 is a functional unit that controls the operation and functions of the entire UPF.The control unit _B700 realizes various processing in the UPF by reading and executing various programs stored in the memory unit _B740 as necessary.

[0069] The network connection unit _B720 is a functional unit for the UPF to connect to a base station device (gNB), and / or SMF, and / or DN within 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 the base station device (gNB), and / or SMF, and / or DN within the 5G AN.

[0070] Explaining in more detail with reference to Figure 2, a UPF in a 5GCN can communicate with a gNB via the N3 interface, with an SMF via the N4 interface, with a DN via the N6 interface, and with other UPFs via the N9 interface by using the network connection unit _A620.

[0071] The memory unit _B740 is a functional unit for storing programs, user data, control information, etc. required for each operation of the UPF.

[0072] The UPF has functions such as an anchor point for intra-RAT mobility or inter-RAT mobility, an external PDU session point for interconnecting to DNs (i.e., a gateway between DNs and core network_B that forwards user data), packet routing and forwarding, an 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, a QoS (Quality of Service) processing function for the user plane, an uplink traffic verification function, downlink packet buffering, and a function to trigger downlink data notifications.

[0073] 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 a function for converting non-IP communication and IP communication. Furthermore, multiple gateways may be gateways that connect the core network_B to a single DN. The UPF may also have connectivity with other NFs and may be connected to each device via other NFs.

[0074] The user plane refers to user data transmitted and received between a UE and a network. The user plane may be transmitted and received using a PDN connection in the case of 4G, or a PDU session in the case of 5G. 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 the 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 referred to as the U-Plane.

[0075] 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 Non-Access-Stratum (NAS) signaling connection between the UE and the 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 the NG RAN and the N2 interface. Hereinafter, the control plane may be referred to as the control plane or the C-Plane.

[0076] 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.

[0077] [2.6. Description of other devices and / or functions and identification information in this embodiment] Next, other devices and / or functions and identification information will be described.

[0078] A network refers to at least a portion of an access network _B, a core network _B, and a DN. Furthermore, one or more devices included in at least a portion of an access network _B, a core network _B, and a 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, 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, receives, and / or processes messages.

[0079] In addition, an NSSF (Network Slice Selection Function) may be a network function (also referred to as an NF) that has the function of selecting a network slice that serves a UE.

[0080] Furthermore, an NWDAF (Network Data Analytics Function) may be an NF that has the function of collecting data from an NF or an application function (also referred to as an AF).

[0081] Furthermore, a PCF (Policy Control Function) may be an NF having a function of determining a policy for controlling the behavior of a network.

[0082] Furthermore, an NRF (Network Repository Function) may be an NF having a service discovery function, which may have a function of providing information about the discovered NF when receiving a discovery request for another NF from another NF.

[0083] A Network Slice Admission Control Function (NSAC) may also monitor and control the number of registered UEs per NS and / or the number of PDU sessions per NS for network slices (NSs) associated with the Network Slice Admission Control (NSAC). The NSACF may also be configured with a maximum number of allowed UEs per NS and / or a maximum number of allowed PDU sessions per NS for each NS associated with the NSAC. The NSACF may also be capable of increasing or decreasing the number of UEs registered with an NS so as not to exceed the maximum number of UEs allowed to register with that NS. The NSACF may also maintain a list of UE IDs registered with an NS associated with the NSAC. When the number of UEs registered with an NS increases (e.g., when a UE sends a new registration request message to the NS), the NSACF may also be capable of checking whether the ID of the UE is already included in the list of UE IDs registered with the NS. If the ID of the UE is not included in the list, the NSACF may further check with the NS whether the maximum number of UEs per NS has been reached. Furthermore, when the registration status of a UE for an NS associated with an NSAC changes during a registration procedure, a deregistration procedure, and / or an NSSAA procedure, the AMF may request the NSACF regarding the maximum number of UEs per NS. The NSACF may also have a function to increase or decrease the number of PDU sessions for an NS so as not to exceed the maximum number of PDU sessions permitted by that NS. When the number of PDU sessions using an NS increases (e.g., when a UE sends a PDU session establishment request message to that NS), the NSACF may also have a function to check for that NS whether the maximum number of UEs per NS has been reached. The SMF may also request the NSACF regarding the maximum number of PDU sessions per NS during a PDU session establishment procedure and / or a PDU session release procedure.

[0084] 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.

[0085] 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. Note that each procedure may be initiated by the UE or the NW.

[0086] Furthermore, an MM (Mobility management) message (also referred to as an NAS MM message) may be an 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, etc.

[0087] 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.

[0088] In addition, the 5GS (5G System) service may be a connection service provided using the core network _B 190. Furthermore, the 5GS service may be a service different from the EPS service or may be a service similar to the EPS service.

[0089] In addition, non-5GS services may be services other than 5GS services, and may include EPS services and / or non-EPS services.

[0090] Also, 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 via IP, but via a communication method other than IP.

[0091] Furthermore, a PDU (Protocol Data Unit) session can be defined as an association between a DN that provides a PDU connectivity service and a UE, but it may also be connectivity established between a UE and an external gateway. In 5GS, a UE can transmit and receive user data to and from a DN by establishing a PDU session via an access network _B and a core network _B. Here, this external gateway may be a UPF, SCEF, or the like. The UE can transmit and receive user data to and from a device such as an application server located in the DN using the PDU session.

[0092] Each device (UE, and / or access network device, and / or core network device) may associate one or more pieces of identification information with a PDU session and manage them. These pieces of identification information may include one or more of the DNN, QoS rule, PDU session type, application identification information, NSI identification information, and access network identification information, or may further include other information. Furthermore, when multiple PDU sessions are established, the identification information associated with the PDU sessions may be the same or different.

[0093] Furthermore, the DNN (Data Network Name) may be identification information for identifying 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).

[0094] Furthermore, 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. Furthermore, Ethernet may 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 if the UE is capable of using both IPv4 and IPv6.

[0095] A PLMN (Public Land Mobile Network) is a communication network that provides mobile radio communication services. A PLMN is a network managed by an operator, which is a communications carrier, and the operator can be identified by a PLMN ID. A PLMN that matches the MCC (Mobile Country Code) and MNC (Mobile Network Code) of a UE's IMSI (International Mobile Subscriber Identity) may be a Home PLMN (HPLMN). Furthermore, the UE may store an Equivalent HPLMN list in its USIM to identify one or more Equivalent HPLMNs (EPLMNs). A PLMN that is different from the HPLMN and / or EPLMN may be a Visited PLMN (VPLMN). A PLMN to which a UE has successfully registered may be a Registered PLMN (RPLMN).

[0096] A network slice (NS) is a logical network that provides specific network capabilities and network characteristics. UEs and / or networks can support network slices (NW slices; NS) in 5GS. A network slice may also be simply referred to as a slice.

[0097] A network slice instance (NSI) is composed of an instance (entity) of a network function (NF) and a set of required resources, forming a deployed network slice. Here, an NF is a processing function in a network, adopted or defined by 3GPP. An NSI is an entity of one or more NSs configured within a core network _B. An NSI may also be composed of virtual network functions (NFs) generated using a network slice template (NST). Here, an NST is associated with resource requirements for providing required communication services and capabilities, and is a logical representation of one or more NFs. In other words, an NSI may be a collection of multiple NFs within the core network _B 190. An NSI may also be a logical network configured to separate user data delivered by services, etc. One or more NFs may be configured within an NS. The NFs configured in an NS may or may not be devices shared with other NSs. A UE and / or a device in the network can 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 one or more APNs. The UE usage type is a parameter value included in the UE registration information and 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.

[0098] Furthermore, S-NSSAI (Single Network Slice Selection Assistance Information) is information for identifying an NS. The S-NSSAI may consist of only an SST (Slice / Service type) or may consist of both an SST and an SD (Slice Differentiator). Here, the SST is information indicating the expected behavior of the NS in terms of functions and services. The SD may be information that interpolates the SST when selecting one NSI from multiple NSIs indicated by the SST. The 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-NSSAIs as default S-NSSAIs in the registration information of the UE. Note that when the S-NSSAI is the default S-NSSAI, if the UE does not send a valid S-NSSAI to the network in a registration request message, the network may provide an NS related to the UE.

[0099] Also, NSSAI (Network Slice Selection Assistance Information) is a collection of S-NSSAIs. 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. Also, the NSSAI may be information used to select an AMF.

[0100] Furthermore, the configured NSSAI (also referred to as 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 configured S-NSSAI. The configured S-NSSAI may be configured to include an S-NSSAI and a mapped S-NSSAI.

[0101] The requested NSSAI (also referred to as the Requested NSSAI) is an NSSAI provided from 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 in a NAS message, such as a registration request message or a PDU session establishment request message, transmitted from the UE to the network, or in a Radio Resource Control (RRC) message including a Non-Access-Stratum (NAS) message.

[0102] Furthermore, the allowed NSSAI (also referred to as the permitted NSSAI or Allowed NSSAI) is information indicating one or more network slices to which the UE is permitted. In other words, the allowed NSSAI is information that identifies the network slice to which the network permits 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 UE information. 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.

[0103] Furthermore, a mapped S-NSSAI (also referred to as a mapped S-NSSAI) is an S-NSSAI of an HPLMN mapped to an S-NSSAI of a registered PLMN in a roaming scenario. The UE may store one or more mapped S-NSSAIs mapped to the configured NSSAI and the S-NSSAI included in the Allowed NSSAI for each access type. Furthermore, the UE may store one or more mapped S-NSSAIs for the S-NSSAI included in the rejected NSSAI.

[0104] Furthermore, a rejected NSSAI (also referred to as a Rejected NSSAI) is information indicating one or more network slices to which a UE is not permitted to connect. In other words, a rejected NSSAI is information identifying a network slice to which a network does not permit a UE to connect. A 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 accept message, a configuration update command, or a registration reject message, or in an RRC message including an NAS message. An S-NSSAI included in a rejected NSSAI may be expressed as a rejected S-NSSAI. The rejected NSSAI may be any one of the first to third rejected NSSAIs, a pending NSSAI, or a combination of these. An S-NSSAI included in a 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.

[0105] 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. If 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.

[0106] Furthermore, 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 included in the first rejected NSSAI as information independent of the access type. That is, the first rejected NSSAI may be information valid for both 3GPP access and non-3GPP access.

[0107] The UE may delete the first rejected NSSAI from its memory if it transitions to an unregistered state in both 3GPP access and non-3GPP access for the current PLMN. In other words, if the UE transitions to an unregistered state for the current PLMN via one access, or if the UE successfully registers to a new PLMN via one access, or if the UE fails to register to the new PLMN via one 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.

[0108] Furthermore, the second rejected NSSAI is a set of one or more S-NSSAIs that are unavailable 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 unavailable in the current registration area.

[0109] Furthermore, 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 included 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 and non-3GPP access. That is, once the UE transitions to an unregistered state for a certain access, the UE may delete the second rejected NSSAI from its memory.

[0110] Furthermore, the third rejected NSSAI is a set of one or more S-NSSAIs that require an NSSAA and for which the NSSAA for that S-NSSAI has failed or been revoked. The third rejected NSSAI may be an NSSAI stored by the UE and / or the 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. In this case, the rejection reason value 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 NSSAA for the S-NSSAI associated with the rejection reason value has failed or been revoked.

[0111] Furthermore, the third rejected NSSAI is valid for 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. That is, 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.

[0112] The third rejected NSSAI identifies a slice that the UE rejected due to an NSSAA failure or revocation from the core network. Specifically, while the UE stores the third rejected NSSAI, it 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 an NSSAA failure. The third rejected NSSAI is information independent of the access type. Specifically, when the UE stores the third rejected NSSAI, the UE may not attempt to send 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 send a registration request message including the S-NSSAI included in the third rejected NSSAI based on a UE policy. Alternatively, the UE may delete the third rejected NSSAI based on the UE policy and transition to a state in which it can transmit a registration request message including an S-NSSAI included in the third rejected NSSAI. In other words, when the UE transmits a registration request message including an 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.

[0113] Furthermore, a pending NSSAI (also referred to as a Pending NSSAI) is an S-NSSAI that requires network slice specific authentication by the network, and is a collection of one or more S-NSSAIs that are not usable in the current PLMN because the network slice specific authentication has not been completed. The pending NSSAI may be a 5GS Rejected NSSAI due to NSSAA or a pending NSSAI. The pending NSSAI may be an NSSAI stored by the UE or the NW, or an NSSAI transmitted 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 transmitted from the NW to the UE, the pending NSSAI may be information including one or more combinations of an S-NSSAI and a rejection reason value. The rejection reason value in this case may be "NSSAA 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 the NSSAA for that S-NSSAI is completed.

[0114] Furthermore, the pending NSSAI is valid for 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. That is, 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.

[0115] Furthermore, the pending NSSAI is an NSSAI consisting of one or more S-NSSAIs that identify slices for which the UE has pending procedures. Specifically, while the UE stores the pending NSSAI, it 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 NSSAA 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 a pending NSSAA. 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 send a registration request message including the S-NSSAI included in the pending NSSAI to both 3GPP access and non-3GPP access.

[0116] 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. Hereinafter, a tracking area may be a TA (Tracking Area). A tracking area may be identified by a TAI (Tracking Area Identity) consisting of a TAC (Tracking area code) and a PLMN.

[0117] A registration area is a collection of one or more TAs assigned to a UE by the AMF. 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 signals for tracking area update. 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.

[0118] The UE ID is information for identifying a UE. Specifically, for example, the UE ID may be a SUCI (Subscription Concealed Identifier), a SUPI (Subscription Permanent Identifier), a GUTI (Globally Unique Temporary Identifier), an IMEI (International Mobile Subscriber Identity), an IMEISV (IMEI Software Version), or a TMSI (Temporary Mobile Subscriber Identity). Alternatively, the UE ID may be other information set in an application or a network. Furthermore, the UE ID may be information for identifying a user.

[0119] Network Slice-Specific Authentication and Authorization (NSSAA) is a function for realizing network slice-specific authentication and authorization. Network slice-specific authentication and authorization allows UE authentication and authorization to be performed outside the core network, such as by a third party. PLMNs and network devices with NSSAA functionality can perform NSSAA procedures for a certain S-NSSAI based on the UE's registration information. Furthermore, UEs with NSSAA functionality can manage and store rejected NSSAIs for pending NSSAA and / or rejected NSSAIs for failed NSSAA. In this document, NSSAA may be referred to as the network slice-specific authentication and authorization procedure or the authentication and authorization procedure.

[0120] An S-NSSAI requiring an NSSAA is an S-NSSAI requiring an NSSAA 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 requiring an NSSAA by associating the S-NSSAI with information indicating whether an NSSAA is required. The core network and / or core network device may further store an S-NSSAI requiring an NSSAA with information indicating whether an NSSAA has been completed, or information indicating that the NSSAA has been completed and is permitted or successful. The core network and / or core network device may manage an S-NSSAI requiring an NSSAA as information unrelated to the access network.

[0121] Also, a UE in single registration mode has only one active MM state. That is, a UE in single registration mode can only be active in either the RM state (5GMM state) in 5GC or the EMM state in EPC. Also, a UE in single registration mode is in 5GC NAS mode when connecting to 5GC, and is in EPC NAS mode when connecting to EPC. Also, since a UE in single registration mode can only be registered to either 5GC or EPC, when moving between EPC and 5GC, mapping between EPS-GUTI (also referred to as 4G-GUTI) and 5G-GUTI is required.

[0122] In addition, a UE in dual registration mode may be able to independently register with 5GC and EPC. A UE in dual registration mode can independently maintain 5G-GUTI and EPS-GUTI (also referred to as 4G-GUTI).

[0123] Next, the identification information transmitted, received, stored, and managed by each device in this embodiment will be described.

[0124] First, the first identification information is information indicating a network slice to which the UE wishes to register. The first identification information may be a Requested NSSAI, which may be an NSSAI provided by the UE to the PLMN when registering with the network. The first identification information may include one or more S-NSSAIs. 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, an S-NSSAI included in an allowed NSSAI associated with one or more current PLMNs, or a combination of the 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.

[0125] Furthermore, the S-NSSAI included in the first identification information may be a rejected NSSAI and / or an S-NSSAI that is not included in a pending NSSAI. Furthermore, the S-NSSAI included in the first identification information may be an S-NSSAI for which an associated back-off timer is not running.

[0126] Furthermore, the eleventh identification information may be information indicating a network slice. Furthermore, the eleventh identification information may be an S-NSSAI. Furthermore, the eleventh identification information may be information indicating an S-NSSAI that has reached the maximum number of UEs or the maximum number of PDU sessions that can be registered in a network slice. Furthermore, the eleventh identification information may be included in an Allowed NSSAI transmitted from the network, may be included in a Rejected NSSAI transmitted from the network, may be included in a Pending NSSAI transmitted from the network, or may be transmitted from the network as information different from these.

[0127] The eleventh identification information may be an NSSAI. The eleventh identification information may be an Allowed NSSAI, a Rejected NSSAI, a Pending NSSAI, or an NSSAI different from these. The eleventh identification information may be configured to include one or more of the twelfth and / or thirteenth identification information.

[0128] The twelfth identification information may be a cause value, and may be indicated as a 5G Mobility Management (5GMM) cause.

[0129] The twelfth identification information may also indicate that the maximum number of UEs per NS has been exceeded, or that the maximum number of UEs per NS has been reached, or that an NS-related quota on the maximum number of UEs has been exceeded.

[0130] In addition, the 12th identification information may indicate congestion, may indicate that redirection to EPC is required, may indicate that no network slices are available, may indicate that there are insufficient resources for a specific NS and DNN, or may indicate that there are insufficient resources for a specific slice.

[0131] The twelfth identification information may be configured to include one or more of the eleventh and / or thirteenth identification information.

[0132] Furthermore, the thirteenth identification information may be a back-off timer value. Specifically, the thirteenth identification information may indicate a period during which the UE is prohibited from transmitting an MM message or an SM message using the S-NSSAI indicated by the eleventh identification information. Furthermore, the thirteenth identification information may indicate a period during which the UE is prohibited from returning to the N1 mode when the UE has performed a system change from the N1 mode to the S1 mode. Furthermore, the thirteenth identification information may indicate a period during which the UE is prohibited from transmitting an MM message or an SM message using the S-NSSAI indicated by the eleventh identification information, although the UE can return to the N1 mode when the UE has performed a system change from the N1 mode to the S1 mode.

[0133] Furthermore, the thirteenth identification information may be configured to include one or more of the eleventh and / or twelfth identification information.

[0134] Furthermore, the fourteenth identification information may be information that includes at least one of the eleventh to thirteenth identification information.

[0135] Furthermore, the 21st identification information is a PDU session ID that identifies the PDU session. Furthermore, the 21st identification information may be a PDU session ID that identifies the PDU session that is requested to be established.

[0136] Furthermore, the 22nd identification information is a PDU session type that identifies the type of the PDU session. Furthermore, the 22nd identification information may be a PDU session type requested by the UE for the PDU session. Furthermore, the 22nd identification information may indicate any of IPv4, IPv6, IPv4v6, Unstructured, and Ethernet (registered trademark).

[0137] Furthermore, the 23rd identification information is the SSC mode. Furthermore, the 23rd identification information may be the SSC mode requested by the UE for the PDU session. Furthermore, the 23rd identification information may indicate any of SSC mode 1, SSC mode 2, and SSC mode 3.

[0138] Furthermore, the 24th identification information is one or more S-NSSAIs. Furthermore, the 24th identification information may be one or more S-NSSAIs requested by the UE for the PDU session to be established. Furthermore, the 24th identification information may be one or more S-NSSAIs selected from the Allowed NSSAIs for the current access type. Specifically, the 24th identification information may be one or more S-NSSAIs allowed by the network as Allowed S-NSSAIs included in the registration accept message in the registration procedure. Furthermore, not including the 24th identification information may be referred to as no S-NSSAI.

[0139] In addition, the 25th identification information is a DNN. In addition, the 25th identification information may be a DNN that identifies the DN to which the PDU session that the UE requests to establish is connected. In addition, not including the 25th identification information may be referred to as no DNN.

[0140] Furthermore, the 26th identification information may be information that includes at least one of the 21st to 25th identification information.

[0141] The 31st identification information may be a PDU session ID that identifies a PDU session. The 31st identification information may be a PDU session ID that identifies a PDU session that is permitted to be established by the network. The 31st identification information may be the same as the 21st identification information.

[0142] The 32nd identification information may be a PDU session type that identifies the type of the PDU session. The 32nd identification information may be a PDU session type selected by the network. The 32nd identification information may indicate any of IPv4, IPv6, IPv4v6, Unstructured, and Ethernet (registered trademark).

[0143] The 33rd identification information may also be an SSC mode. The 33rd identification information may also be an SSC mode selected by the network for the PDU session. The 33rd identification information may also indicate SSC mode 1, SSC mode 2, or SSC mode 3.

[0144] Furthermore, the 34th identification information is one or more S-NSSAIs. The 34th identification information may be the same as the 24th identification information. The 34th identification information may be configured to include one or more of the 36th and / or 37th identification information.

[0145] In addition, the 35th identification information is a DNN. In addition, the 35th identification information may be a DNN that identifies the DN to which the PDU session is connected. The 35th identification information may be the same as the 25th identification information.

[0146] The 36th identification information may be a cause value. The 36th identification information may be indicated as a 5G Mobility Management (5GMM) cause and / or a 5G Session Management (5GSM) cause.

[0147] Additionally, the 36th identification information may indicate that the maximum number of PDU sessions per NS has been exceeded, or that the maximum number of PDU sessions per NS has been reached, or that an NS-related quota regarding the maximum number of PDU sessions has been exceeded.

[0148] In addition, the 36th identification information may indicate insufficient resources (Insufficient resources), may indicate insufficient resources for a specific NS and DNN (Insufficient resources for a specific slice and DNN), may indicate insufficient resources for a specific NS (Insufficient resources for a specific slice), or may indicate that the maximum number of PDU sessions has been reached.

[0149] Furthermore, the 36th identification information may be configured to include one or more of the 34th and / or 37th identification information.

[0150] Furthermore, the 37th identification information may be a back-off timer value. Specifically, the 37th identification information may indicate a period during which the UE is prohibited from transmitting an MM message or an SM message using the S-NSSAI indicated by the 34th identification information. Furthermore, the 37th identification information may indicate a period during which the UE is prohibited from returning to the N1 mode when the UE has performed a system change from the N1 mode to the S1 mode. Furthermore, the 37th identification information may indicate a period during which the UE is prohibited from transmitting an MM message or an SM message using the S-NSSAI indicated by the 11th identification information, although the UE can return to the N1 mode when the UE has performed a system change from the N1 mode to the S1 mode.

[0151] Furthermore, the 37th identification information may be configured to include one or more of the 34th and / or 36th identification information.

[0152] Furthermore, the 38th identification information may be information that includes at least one of the 31st to 37th identification information.

[0153] 3. First Embodiment First, procedures used in the first embodiment will be described. The procedures used in the first embodiment include a registration procedure, a PDU session establishment procedure, etc. Each procedure will be described below.

[0154] In the first embodiment, as shown in FIG. 2, an example will be described in which the HSS and UDM, the PCF and PCRF, the SMF and PGW-C, and the UPF and PGW-U are configured as the same device / function (i.e., the same physical hardware, the same logical hardware, or the same software). However, the contents described in this embodiment are also applicable to cases in which these are configured as different devices / functions (i.e., different physical hardware, different logical hardware, or different software). For example, data may be transmitted and received directly between these, or may be transmitted and received via the N26 interface between the AMF and MME, or may be transmitted and received via the UE.

[0155] 3.1. Registration Procedure Next, the registration procedure will be described with reference to FIG. 6. In this chapter, this registration procedure may be simply referred to as this procedure. The registration procedure is a procedure initiated by the UE to register with the access network _B and / or the core network _B and / or the DN. If the UE is not registered with a network, it can execute this procedure at any time, for example, when powered on. In other words, if the UE is in a deregistered state (5GMM-DEREGISTERED state), it can start this procedure at any time. Furthermore, each device (especially the UE and the AMF) can transition to a registered state (5GMM-REGISTED 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 unregistered state) for 3GPP access and the registration state for non-3GPP access.

[0156] Furthermore, the registration procedure may be a procedure for updating the location registration information of the UE in the network and / or for the UE to periodically notify the network of the status of the UE and / or for updating certain parameters related to the UE in the network.

[0157] The UE may initiate the registration procedure when performing 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 the registration procedure when the context of each device needs to be updated due to PDU session disconnection or invalidation. Furthermore, the UE may initiate the registration procedure when there is a change in the UE's capability information and / or preferences regarding PDU session establishment. Furthermore, the UE may initiate the registration procedure periodically. Furthermore, the UE may initiate the registration procedure based on the completion of the registration procedure, the completion of the PDU session establishment procedure, or information received from the network during each procedure. In other words, the UE may initiate the registration procedure after performing the procedures in Chapter 3.1 and / or Chapter 3.2. However, the UE may also perform the registration procedure at any timing.

[0158] The procedure for the UE to transition from a state where it is not registered in the network (unregistered state) to a state where it is registered (registered state) may be an initial registration procedure or a registration procedure for initial registration. Furthermore, the registration procedure executed when the UE is registered in the network (registered state) may be a registration procedure for mobility and periodic registration update or a mobility and periodic registration procedure.

[0159] The registration process details described below are applicable to both.

[0160] First, the UE starts the registration procedure by transmitting a registration request message to the AMF (S600) (S602) (S604). Specifically, the UE transmits an RRC message including a registration request message to a base station device (also referred to as a 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 base station device. 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.

[0161] Here, the UE may transmit the first identification information by including it in the registration request message and / or the RRC message. Here, the first identification information may be as described in Chapter 2.6. Furthermore, the UE may transmit the registration request message and / or the RRC message by including identification information indicating the type of this procedure. Here, the identification information indicating the type of this procedure may be a 5GS registration type IE (Information Element). The 5GS registration type IE is information for indicating the type of registration requested, and may indicate initial registration, mobility registration updating, periodic registration updating, or emergency registration.

[0162] The UE may include UE capability information in the registration request message to inform the network of the capabilities that the UE supports, where the UE capability information may be a 5GMM capability IE for 5GS.

[0163] The UE may transmit this identification information by including it in a control message different from the above, for example, a control message of a layer lower than the RRC layer (for example, a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, a Packet Data Convergence Protocol (PDCP) layer, a Service Data Adaptation Protocol (SDAP) layer, etc.) Note that by transmitting this identification information, the UE may indicate that it supports each function, may indicate a request from the UE, or may indicate both of these.

[0164] Furthermore, the UE may select and decide whether to transmit the first 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.

[0165] The UE may store the allowed NSSAI, configured NSSAI, rejected NSSAI, and mapped S-NSSAI.

[0166] The UE may include information other than the first identification information in the registration request message and / or the RRC message, for example, a UE ID and / or a PLMN ID and / or an AMF identification information, and may transmit the message. Here, the AMF identification information may be information that identifies an AMF or a set of AMFs, for example, a 5G-S-TMSI (5G S-Temporary Mobile Subscription Identifier) ​​or a GUAMI (Globally Unique AMF Identifier).

[0167] When the base station device receives an RRC message including a registration request message, it selects an AMF to which to forward the registration request message (S602). Note that the base station device may select an AMF based on identification information included in the registration request message and / or the RRC message. Specifically, when the base station device receives first identification information, it may select an AMF to which to send the registration request message based on the first identification information. Specifically, the base station device may select an AMF included in the network slice identified by the first identification information, or an AMF having connectivity to the network slice identified by the first identification information.

[0168] Note that the method of selecting AMF is not limited to this, and the base station device may select AMF based on other conditions.

[0169] The base station device extracts the registration request message from the received RRC message and transfers the registration request message to the selected AMF (S604). Note that if the first 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 transferred to the selected AMF together with the registration request message (S604).

[0170] When the AMF receives the registration request message, the AMF may perform a first condition determination. The first condition determination is for determining whether the network accepts the UE's request. When the AMF determines that the first condition determination is true, the AMF may perform the procedures from S610 to S612. Also, when the AMF determines that the first condition determination is false, the AMF may perform the procedure of S610.

[0171] In addition, the first condition determination may be performed by a network function (also referred to as NF) other than the AMF. The NF may be, for example, an NSACF. When an NF other than the AMF performs the first condition determination, the AMF may provide the NF with information necessary to perform the first condition determination, specifically, at least a portion of the information received from the UE (S606). Then, when the NF determines whether the first condition determination is true or false based on the information received from the AMF, it may convey information including the result of the first condition determination (i.e., true or false) to the AMF. The AMF may determine identification information and / or a control message to be transmitted to the UE based on the result of the first condition determination received from the NF.

[0172] If the first condition determination is true, the control message transmitted and received in S610 may be a Registration accept message, and if the first condition determination is false, the control message transmitted and received in S610 may be a Registration reject message.

[0173] 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.

[0174] For example, if the network permits the UE's request, the first condition determination may be determined as true, and if the network does not permit the UE's request, the first condition determination may be determined as false. Furthermore, 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 determined as true, and if the function requested by the UE is not supported, the first condition determination may be determined as false. Furthermore, if the identification information to be transmitted and received is permitted, the first condition determination may be determined as true, and if the identification information to be transmitted and received is not permitted, the first condition determination may be determined as false. Furthermore, if the registration request is rejected due to reasons such as exceeding the maximum number of UEs per NS, reaching the maximum number of UEs per NS, exceeding an NS-related quota on the maximum number of UEs, congestion, redirection to EPC required, no network slices available, insufficient resources for a specific NS and DNN, or insufficient resources for a specific NS (hereinafter referred to as rejection reason 1), the first condition determination may be determined to be false. Furthermore, if the registration request is not rejected due to rejection reason 1, the first condition determination may be determined to be true.

[0175] The AMF may transmit one or more of the identification information items 11 to 14 in a control message. Here, the identification information items 11 to 14 may be as described in Chapter 2.6. By transmitting these identification information items and / or the control message, the AMF may indicate that the network supports each function, may indicate that the UE's request has been accepted, may indicate that the UE's request has not been permitted, or may indicate a combination of these. Furthermore, when multiple pieces of identification information are transmitted and received, two or more pieces of identification information may be configured as one or more pieces of identification information. Note that 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 as different identification information.

[0176] When the AMF receives a registration request message including the first identification information from the UE, it may include at least one of the eleventh to fourteenth identification information in a control message and send it.

[0177] In addition, even if the AMF receives a registration request message from the UE that does not include the first identification information, the AMF may include at least one of the 11th to 14th identification information in the control message and send it.

[0178] 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 eleventh to fourteenth 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.

[0179] When sending a control message, the AMF does not have an allowed S-NSSAI (allowed NSSAI) for the UE, but if it plans to perform an NSSAA procedure after completing this procedure or in parallel with this procedure, or if an NSSAA procedure is currently being performed between the UE and the network, or if it sent a pending NSSAI in the control message, it may send an empty value in the allowed NSSAI.

[0180] Furthermore, the AMF may determine which of the 11th to 14th identification information 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.

[0181] In addition, the AMF may indicate that the UE's request has been accepted by sending a registration acceptance message, or may indicate that the UE's request has been rejected by sending a registration rejection 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.

[0182] In addition, when rejecting a registration request due to rejection reason 1, the network (e.g., AMF and / or NSACF) may set the 12th identification information to: exceeded maximum number of UEs per NS, and / or reached maximum number of UEs per NS, and / or exceeded NS-related quota on maximum number of UEs, and / or congestion, and / or redirection to EPC required, and / or no network slices available, and / or insufficient resources for specific slice and DNN, and / or insufficient resources for specific slice.

[0183] In this case, the network (e.g., AMF and / or NSACF) may consider the S1 mode capability of the UE to determine the rejection using the twelfth identity. Here, the S1 mode may refer to a mode of the UE that can access a 4G core network via a 4G access network, and the S1 mode capability may refer to the UE having the S1 mode capability, i.e., the UE having the capability to access a 4G core network via a 4G access network, or may refer to the UE having the capability to communicate using 4G.

[0184] Furthermore, when the AMF and / or NSACF permits a UE request because rejection reason 1 does not apply, or when the AMF and / or NSACF permits the use of an S-NSSAI included in the first identification information received from the UE, the AMF and / or NSACF may designate the S-NSSAI as an allowed S-NSSAI and include the allowed S-NSSAI in the 11th identification information. Furthermore, when the AMF and / or NSACF permits a UE request because rejection reason 1 does not apply, or when the AMF and / or NSACF permits the use of an S-NSSAI included in the first identification information received from the UE, the AMF and / or NSACF may designate the S-NSSAI as an allowed S-NSSAI and include an Allowed NSSAI that includes the allowed S-NSSAI in the 11th identification information.

[0185] Furthermore, when the AMF and / or NSACF does not permit (reject) a UE request because it falls under rejection reason 1, or when it does not permit (reject) the use of an S-NSSAI included in the first identification information received from the UE, it may designate the S-NSSAI as a rejected S-NSSAI and include the rejected S-NSSAI in the 11th identification information. Furthermore, when the AMF and / or NSACF does not permit (reject) a UE request because it falls under rejection reason 1, or when it does not permit (reject) the use of an S-NSSAI included in the first identification information received from the UE, it may designate the S-NSSAI as a rejected S-NSSAI and include an Allowed NSSAI or Rejected NSSAI including the rejected S-NSSAI in the 11th identification information.

[0186] In addition, the AMF and / or NSACF do not need to include the 12th identification information when allowing the UE's request or when allowing the use of the S-NSSAI included in the first identification information received from the UE because rejection reason 1 does not apply.

[0187] In addition, the AMF and / or NSACF may include a 12th identification information if they do not authorize (reject) the UE's request because it falls under rejection reason 1, or if they do not authorize (reject) the use of the S-NSSAI included in the first identification information received from the UE.

[0188] In addition, if the AMF and / or NSACF does not authorize (reject) the UE's request because it falls under rejection reason 1, or if it does not authorize (reject) the use of the S-NSSAI included in the first identification information received from the UE, it may include a backoff timer value in the 13th identification information.

[0189] The UE receives the control message (registration accept message or registration reject message) and / or the transmitted identification information items 11 to 14 via the base station device (S610). If the control message is a registration accept message, the UE can recognize by receiving the registration accept message that the UE's request in the registration request message has been accepted and the contents of the various identification information included in the registration accept message. Also, if the control message is a registration reject message, the UE can recognize by receiving the registration reject message that the UE's request in the registration request message has been rejected and the contents of the various identification information included in the registration reject message.

[0190] Furthermore, if the UE receives the twelfth identification information via a non-3GPP access, it may be considered an abnormal case. Also, if the UE receives the twelfth identification information via a cell belonging to an SNPN, it may be considered an abnormal case.

[0191] Furthermore, when the UE receives the twelfth identification information, the UE may set the 5GS update status (also referred to as 5U status) of the UE to 5U3 ROAMING NOT ALLOWED. Here, the 5U status specifies the status of the UE in the 5GMM layer, and the 5U3 ROAMING NOT ALLOWED may be a status indicating that the previous registration, or the previous service request, or the previous registration procedure for mobility and periodic registration update was performed correctly (successfully), but the response from the AMF was negative.

[0192] Furthermore, upon receiving the twelfth identification information, the UE may delete all 5G-GUTIs, previously registered TAIs, TAI lists, etc. Furthermore, the UE may reset a registration attempt counter. Here, the registration attempt counter is used to limit the number of registration attempts. In other words, the registration attempt counter may be used to limit the number of times a registration procedure is performed. The registration attempt counter is incremented by one each time the registration procedure fails unless it is set to 5, but may be reset in certain cases. The registration attempt counter is also reset when the UE is powered on, when a USIM is inserted, when the registration procedure is successfully completed, etc.

[0193] Furthermore, when the UE receives the 12th identification information, if E-UTRA capability is disabled, the UE may enable E-UTRA capability, may disable N1 mode capability for 3GPP access, or may transition to a 5GMM-DERIGISTERED.NO-CELL-AVAILABLE state. Here, E-UTRA capability may mean that the UE has the capability to access a 4G core network via a 4G access network, or may mean that the UE has the capability to access a 4G access network, or may mean the capability to communicate using 4G. Furthermore, N1 mode means a UE mode in which the UE can access a 5G core network via a 5G access network, and N1 mode capability may mean that the UE has N1 mode capability, i.e., that the UE has the capability to access a 5G core network via a 5G access network. Furthermore, 5GMM-DERIGISTERED.NO-CELL-AVAILABLE may mean that a 5G cell cannot be selected.

[0194] Furthermore, if the UE receives the 12th identity via 3GPP access, the UE is operating in single registration mode, and the attach procedure in EPS is rejected using the 12th identity, the UE may operate using the EMM state, EPS update status, 4G-GUTI, attach attempt counter, etc. That is, the UE may operate using 4G parameters instead of 5G parameters. Here, the attach attempt counter is used to limit the number of attach attempts. In other words, the attach attempt counter may be used to limit the number of times the attach procedure is performed. The attach attempt counter is incremented by one each time the registration procedure fails unless it is set to 5, but may be reset in certain cases. The attach attempt counter is also reset when the UE is powered on, when a USIM is inserted, when the attach procedure is successfully completed, etc.

[0195] Furthermore, if the UE receives the 12th identity via 3GPP access, the UE is operating in single registration mode, and the tracking area update procedure in EPS is rejected using the 12th identity, the UE may operate using the EMM state, EPS update status, 4G-GUTI, tracking area updating attempt counter, etc. That is, the UE may operate using 4G parameters instead of 5G parameters. Here, the tracking area update attempt counter is used to limit the number of tracking area update attempts. In other words, the tracking area update attempt counter may be used to limit the number of times the tracking area update procedure is performed. The tracking area update attempt counter is incremented by one each time the registration procedure fails unless it is set to 5, but may be reset in certain cases. The tracking area update attempt counter is also reset when the UE is powered on, when a USIM is inserted, when the tracking area update procedure is successfully completed, etc.

[0196] Also, if the UE receives the 12th identification information and disables the N1 mode capability, and if the lower layers of the UE do not provide information that the current E-UTRA cell is connected to the EPC, the UE may search for a suitable E-UTRA cell to connect to the EPC.

[0197] Also, if the UE receives the 12th identification information and disables the N1 mode capability, and if the lower layers of the UE provide information that the current E-UTRA cell is connected to the EPC, it may perform core network selection to select the EPC.

[0198] Furthermore, if the UE receives the 12th identification information and disables the N1 mode capability, and if the lower layers of the UE cannot find an E-UTRA cell connecting to the EPC, the UE may indicate to the lower layers that it will continue camping on the E-UTRA cell connecting to the 5GC, or may start a timer, or may transition to a 5GMM-REGISTERED.LIMITED-SERVICE state. Here, 5GMM-REGISTERED.LIMITED-SERVICE may be a state in which the UE knows that the cell it selected cannot provide normal service. Then, when the timer expires, the UE may enable the N1 mode capability for 3GPP access.

[0199] Furthermore, if the UE receives an 11th identification information including an Allowed S-NSSAI, the UE may recognize that it is allowed to use the S-NSSAI and / or that it is allowed to register with the network and / or that the UE's request is allowed.

[0200] Furthermore, if the UE receives an 11th identification information including an Allowed S-NSSAI but does not receive a 12th identification information and / or a 13th identification information, the UE may recognize that it is allowed to use the S-NSSAI and / or that it is allowed to register with the network and / or that the UE's request is allowed.

[0201] Furthermore, even if the UE receives an 11th identification information including an Allowed S-NSSAI, if the UE also receives a 12th identification information and / or a 13th identification information, the UE may recognize that use of the S-NSSAI is not permitted (rejected), and / or that registration with the network is not permitted (rejected), and / or that the UE's request is not permitted (rejected).

[0202] Furthermore, if the UE receives an 11th identification information including a Rejected S-NSSAI, the UE may recognize that use of the S-NSSAI is not permitted (rejected), and / or registration with the network is not permitted (rejected), and / or the UE's request is not permitted (rejected).

[0203] Furthermore, if the UE receives an 11th identification information including a Rejected S-NSSAI and also receives a 12th identification information and / or a 13th identification information, the UE may recognize that use of the S-NSSAI is not permitted (rejected), and / or that registration with the network is not permitted (rejected), and / or that the UE's request is not permitted (rejected).

[0204] Furthermore, when the UE receives the 13th identification information, the UE may set a back-off timer value indicated by the 13th identification information to a timer that the UE has and that corresponds to the S-NSSAI indicated by the 11th identification information, and start the timer.The UE may not be able to transmit an MM message and / or an SM message for the S-NSSAI while the timer corresponding to the S-NSSAI indicated by the 11th identification information is running.The UE may be able to transmit an MM message and / or an SM message for the S-NSSAI when the timer corresponding to the S-NSSAI indicated by the 11th identification information expires.Note that the UE may transmit an MM message and / or an SM message for an S-NSSAI other than the S-NSSAI even if the timer corresponding to the S-NSSAI indicated by the 11th identification information is running.

[0205] Furthermore, the UE may determine to communicate via E-UTRAN and / or EPC and / or EPS, or to perform a system change from N1 mode to S1 mode, or to change from communication using 5G to communication using 4G, based on receiving the eleventh identification information, and / or the twelfth identification information, and / or the thirteenth identification information, and / or the fourteenth identification information. In this case, the UE may perform an attach procedure and / or a tracking area update procedure in the EPS.

[0206] Furthermore, even if the UE performs an attach procedure and / or a tracking area update procedure in EPS, the UE may continue or stop the operation of the timer corresponding to the S-NSSAI indicated by the eleventh identification information. If the UE continues the operation of the timer corresponding to the S-NSSAI indicated by the eleventh identification information, the UE may not be able to transmit an MM message and / or an SM message for the S-NSSAI in 5GS until the timer expires. Then, when the timer expires, the UE may be able to transmit an MM message and / or an SM message for the S-NSSAI in 5GS. If the UE stops the operation of the timer corresponding to the S-NSSAI indicated by the eleventh identification information, the UE may be able to transmit an MM message and / or an SM message for the S-NSSAI in 5GS.

[0207] The UE may also start a timer to release the NAS signaling connection if it receives a registration reject message including the 12th identity.

[0208] If the control message is a registration accept message, the UE can further transmit a registration complete message to the AMF via the base station device as a response message to the registration accept message (S612). Here, the registration complete message is an NAS message transmitted and received on the N1 interface, but may be transmitted and received between the UE and the base station device by being included in an RRC message.

[0209] The AMF receives the registration completion message via the base station device (S612). Furthermore, each device completes this procedure based on the transmission and reception of the registration acceptance message and / or the registration completion message.

[0210] Additionally, each device may complete the registration procedure based on sending and receiving a registration rejection message.

[0211] 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 accept message and / or a registration complete message, or may transition to or maintain a state in which the UE is not registered in the network on the access from which the registration reject message was received for the current PLMN (RM_DEREGISTERED state or 5GMM-DEREGISTERED state) based on the transmission and reception of a registration reject message. Also, the transition to each state of each device may be based on the transmission and reception of a registration complete message or the completion of the registration procedure.

[0212] Furthermore, each device may perform processing based on the information transmitted and received during the registration procedure based on the completion of the registration procedure. For example, if the device transmits or receives information indicating that some of the UE's requests have been rejected, the device may recognize the reason why the UE's requests have been rejected. Furthermore, each device may perform this procedure again based on the reason why the UE's requests have been rejected, or may perform the registration procedure for core network_A or another cell.

[0213] Furthermore, 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 the completion of the registration procedure.

[0214] [3.2. PDU Session Establishment Procedure] Next, the PDU session establishment procedure will be explained using Fig. 7. In this chapter, this PDU session establishment procedure may be simply referred to as this procedure.

[0215] The UE may also perform this procedure after performing the procedures in Chapter 3.1 and / or Chapter 3.2 one or more times, or may perform this procedure while the UE is registered with the network.

[0216] The UE may also determine whether to perform this procedure based on messages and / or information obtained in the procedures of Chapter 3.1 and / or Chapter 3.2. For example, if the UE receives a registration accept message in the procedures of Chapter 3.1, the UE may perform this procedure. If the UE receives an eleventh identification including an allowed S-NSSAI in the procedures of Chapter 3.1, the UE may also perform this procedure. If the UE receives a thirteenth identification in the procedures of Chapter 3.1, the UE may not initiate this procedure for the S-NSSAI until the timer corresponding to the S-NSSAI indicated by the eleventh identification received simultaneously with the thirteenth identification expires. If the UE receives a thirteenth identification in the procedures of Chapter 3.1, the UE may also initiate this procedure for an S-NSSAI other than the S-NSSAI, regardless of whether the timer corresponding to the S-NSSAI indicated by the eleventh identification received simultaneously with the thirteenth identification expires.

[0217] First, the UE initiates the PDU session establishment procedure by sending a NAS message including an N1 SM container containing a PDU session establishment request message to the AMF via the access network (S800). The NAS message is, for example, a message sent via the N1 interface and may be an uplink NAS transport (UL NAS TRANSPORT) message. By sending the PDU session establishment request message, the UE may start a timer related to retransmission of the PDU session establishment request message.

[0218] Here, the access network may be a 3GPP access or a non-3GPP access and may include a base station device, that is, the UE sends a NAS message to the AMF via the base station device.

[0219] In addition, the UE can notify the network side of its request by sending a PDU session establishment request message, an N1 SM container, and / or an NAS message containing at least one of the identification information items 21 to 26. Here, the identification information items 21 to 26 may be as defined in Chapter 2.6.

[0220] Furthermore, the UE may determine which of the 21st to 26th identification information to send 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.

[0221] For example, if the UE receives 11th identification information including an allowed S-NSSAI in the procedure of Chapter 3.1, it may send 24th identification information including the S-NSSAI indicated by the 11th identification information.

[0222] Here, no S-NSSAI may mean that the UE does not include the 24th identification information in the PDU session establishment request message, and / or the N1 SM container, and / or the NAS message.

[0223] Also, no DNN may mean that the UE does not include the 25th identification information in the PDU session establishment request message, and / or the N1 SM container, and / or the NAS message.

[0224] In addition, the UE may transmit this identification information in a control message other than the above, such as a control message of a layer lower than the NAS layer (e.g., RRC layer, MAC layer, RLC layer, PDCP layer, SDAP layer, etc.) or a control message of a layer higher than the NAS layer (e.g., transport layer, session layer, presentation layer, application layer, etc.).

[0225] Next, when the AMF receives the NAS message, it can recognize what the UE is requesting and / or the contents of the information contained in the NAS message (message, container, information, etc.).

[0226] Here, the AMF may or may not perform a third condition determination. The third condition determination may be for determining whether the network accepts the UE's request. If the AMF determines that the third condition determination is true, it may start the procedure from S802 onward in FIG. 7. If the AMF determines that the third condition determination is false, it may send a control message to the UE.

[0227] Note that the third condition determination may be performed by an NF other than the AMF. The NF may be, for example, an NSACF. When an NF other than the AMF performs the third condition determination, the AMF may provide the NF with information necessary to perform the third condition determination, specifically, at least a portion of the information received from the UE. Then, when the NF determines whether the third condition determination is true or false based on the information received from the AMF, it may convey information including the result of the third condition determination (i.e., true or false) to the AMF. The AMF may determine identification information and / or a control message to be transmitted to the UE based on the result of the third condition determination received from the NF.

[0228] Furthermore, the third condition determination may be performed based on information received from the UE (message, container, information), and / or information received from the AMF (message, container, information), and / or subscription information, and / or network capability information, and / or UE policy, and / or operator policy, and / or network status, and / or user registration information, and / or information held by the AMF, and / or information held by the NSACF, etc.

[0229] For example, if the network permits the UE's request, the third condition determination may be determined as true, and if the network does not permit the UE's request, the third condition determination may be determined as false. Furthermore, if the network to which the UE is connected and / or a device within the network supports the function requested by the UE, the third condition determination may be determined as true, and if the function requested by the UE is not supported, the third condition determination may be determined as false. Furthermore, if the transmitted and received identification information is permitted, the third condition determination may be determined as true, and if the transmitted and received identification information is not permitted, the third condition determination may be determined as false. Furthermore, if the request to establish a PDU session is rejected due to reasons such as exceeding the maximum number of PDU sessions per NS, reaching the maximum number of PDU sessions per NS, exceeding an NS-related quota on the maximum number of PDU sessions, congestion, or the need for redirection to EPC (Redirection to EPC required), or no available NS (No network slices available), or insufficient resources for a specific NS and DNN (Insufficient resources for a specific slice), or insufficient resources for a specific NS (Insufficient resources for a specific slice) (hereinafter referred to as rejection reason 2), the third condition determination may be determined to be false. Furthermore, if the request to establish a PDU session is not rejected due to rejection reason 2, the third condition determination may be determined to be true.

[0230] The conditions for determining whether the third condition determination is true or false are not limited to the above-mentioned conditions.

[0231] Furthermore, when rejecting the PDU session establishment request due to rejection reason 2, the network (e.g., AMF and / or NSACF) may set the maximum number of PDU sessions per NS exceeded, and / or the maximum number of PDU sessions per NS reached, and / or the NS-related quota for the maximum number of PDU sessions exceeded, and / or congestion, and / or redirection to EPC required, and / or no network slices available, and / or insufficient resources for a specific NS and DNN, and / or insufficient resources for a specific slice, to the 36th identification information. Then, the network (e.g., AMF and / or NSACF) may transmit a control message including the 31st, 34th to 38th identification information to the UE.

[0232] In this case, the network (e.g., AMF and / or NSACF) may take into account the UE's S1 mode capability to determine whether to reject using the 36th identity.

[0233] Furthermore, if the network (e.g., AMF and / or NSACF) does not receive the 24th identification information, it may not include the 34th identification information in the control message, or it may send the 34th identification information indicating no S-NSSAI.

[0234] Furthermore, if the network (e.g., AMF and / or NSACF) does not receive the 25th identification information, it may not include the 35th identification information in the control message, or it may include the 35th identification information indicating no DNN and send it.

[0235] If the UE receives a control message from the AMF containing the 36th identification indicating a 5GMM cause, the UE may notify the 5GSM sublayer of the UE that the 5GSM message could not be forwarded due to the information indicated by the 36th identification. In this case, the UE may treat the maximum number of PDU sessions of the PLMN performing this procedure as the maximum number of PDU sessions per NS. The UE may also abort this procedure or stop the timer associated with retransmission of the PDU session establishment request message, which was started by transmitting the PDU session establishment request message.

[0236] Next, if the third condition determination is not performed, or if the third condition determination is performed and determined to be true, the AMF selects an SMF as a transfer destination for at least part of the information, etc. (message, container, information) included in the NAS message received from the UE (S802). Note that the AMF may select the transfer destination SMF based on the information, etc. (message, container, information) included in the NAS message, and / or subscriber information, and / or network capability information, and / or UE policy, and / or operator policy, and / or network status, and / or user registration information, and / or context held by the AMF, etc.

[0237] Next, the AMF sends at least a portion of the information (message, container, information) contained in the NAS message received from the UE to the selected SMF, for example via the N11 interface (S804).

[0238] Next, when the SMF receives information (messages, containers, information) sent from the AMF, it can recognize what the UE is requesting and / or the content of the information (messages, containers, information) received from the AMF.

[0239] Here, the SMF may perform a second condition determination. The second condition determination may be for determining whether the network accepts the UE request. If the SMF determines that the second condition determination is true, it may start the procedure of (A) in Figure 7, and if the SMF determines that the second condition determination is false, it may start the procedure of (B) in Figure 7.

[0240] Note that the second condition determination may be performed by an NF other than the SMF. The NF may be, for example, an NSACF. When an NF other than the SMF performs the second condition determination, the SMF may provide the NF with information necessary for performing the second condition determination, specifically, at least a portion of the information received from the UE (S806). Then, when the NF determines whether the second condition determination is true or false based on the information received from the SMF, it may convey information including the result of the second condition determination (i.e., true or false) to the SMF. The SMF may determine identification information and / or a control message to be transmitted to the UE based on the result of the second condition determination received from the NF.

[0241] Furthermore, the second condition determination may be performed based on information received from the UE (message, container, information), and / or information received from the AMF (message, container, information), and / or subscription information, and / or network capability information, and / or UE policy, and / or operator policy, and / or network status, and / or user registration information, and / or information held by the SMF, and / or information held by the NSACF, etc.

[0242] For example, if the network permits the UE's request, the second condition determination may be determined as true, and if the network does not permit the UE's request, the second condition determination may be determined as false. Furthermore, if the network to which the UE is connected and / or a device within the network supports the function requested by the UE, the second condition determination may be determined as true, and if the function requested by the UE is not supported, the second condition determination may be determined as false. Furthermore, if the transmitted and received identification information is permitted, the second condition determination may be determined as true, and if the transmitted and received identification information is not permitted, the second condition determination may be determined as false. Furthermore, if the PDU session establishment request is rejected due to rejection reason 2, the second condition determination may be determined as false. Furthermore, if the PDU session establishment request is not rejected due to rejection reason 2, the second condition determination may be determined as true.

[0243] In addition, when rejecting a PDU session establishment request due to rejection reason 2, the network (e.g., SMF and / or NSACF) may set the 36th identification information to: exceeded maximum PDU sessions per NS, and / or reached maximum PDU sessions per NS, and / or exceeded NS-related quota on maximum PDU sessions, and / or congestion, and / or redirection to EPC required, and / or no network slices available, and / or insufficient resources for specific slice and DNN, and / or insufficient resources for specific slice.

[0244] In this case, the network (e.g., SMF and / or NSACF) may take into account the UE's S1 mode capability to determine whether to reject using the 36th identity.

[0245] The conditions for determining whether the second condition is true or false are not limited to the above-mentioned conditions.

[0246] Next, each step of the procedure in FIG. 7(A) will be explained.

[0247] Next, the SMF may select a UPF for the PDU session to be established and send an N4 session establishment request message to the selected UPF, for example, via the N4 interface (S808). The N4 session establishment request message may include at least a portion of the PCC rules received from the PCF.

[0248] Here, the SMF may select one or more UPFs based on information received from the AMF (message, container, information), and / or information such as PCC rules received from the PCF, and / or subscriber information, and / or network capability information, and / or UE policy, and / or operator policy, and / or network status, and / or user registration information, and / or context held by the SMF, etc. If multiple UPFs are selected, the SMF may send an N4 session establishment request message to each UPF. Here, it is assumed that UPF_230 is selected.

[0249] Next, when the UPF receives the N4 session establishment request message (S808), it can recognize the content of the information received from the SMF. Furthermore, based on the reception of the N4 session establishment request message, the UPF may send an N4 session establishment response message to the SMF, for example, via the N4 interface (S810).

[0250] Next, when the SMF receives an N4 session establishment response message as a response message to the N4 session establishment request message, it can recognize the contents of the information received from the UPF.

[0251] Next, the SMF sends an N1 SM container, N2 SM information, and / or PDU session ID to the AMF, for example, via the N11 interface, based on the reception of the PDU session establishment request message, and / or the selection of the UPF, and / or the reception of the N4 session establishment response message (S812), where the N1 SM container may include a PDU session establishment accept message.

[0252] Next, the AMF that has received the N1 SM container, and / or the N2 SM information, and / or the PDU session ID, transmits a NAS message to the UE via a base station device included in the access network (S814) (S816). Here, the NAS message is transmitted, for example, via the N1 interface. The NAS message may be a downlink NAS transport (DL NAS TRANSPORT) message.

[0253] Specifically, the AMF transmits an N2 PDU session request message to a base station device included in the access network (S814). The base station device that receives the N2 PDU session request message transmits an NAS message to the UE (S816). Here, the N2 PDU session request message may include an NAS message and / or N2 SM information. The NAS message may also include a PDU session ID and / or an N1 SM container.

[0254] The PDU session establishment acceptance message may be a response message to a PDU session establishment request, and may indicate that the establishment of the PDU session has been accepted.

[0255] Here, the SMF and / or AMF may indicate that at least part of the UE's request in the PDU session establishment request message has been accepted by sending a PDU session establishment acceptance message, and / or an N1 SM container, and / or a PDU session ID, and / or an NAS message, and / or N2 SM information, and / or an N2 PDU session request message.

[0256] Here, the SMF and / or AMF and / or NSACF may include at least one of the identification information items 31 to 35 and 38 in the PDU session establishment accept message, and / or the N1 SM container, and / or the NAS message, and / or the N2 SM information, and / or the N2 PDU session request message and send it. Here, the identification information items 31 to 35 and 38 may be as described in Chapter 2.6.

[0257] In addition, the SMF and / or NSACF do not need to include the 36th identification information when allowing the UE's request or when allowing the establishment of a PDU session via the S-NSSAI included in the 24th identification information received from the UE because rejection reason 2 does not apply.

[0258] Furthermore, when the SMF and / or NSACF approves the UE's request because rejection reason 2 does not apply, or when they approve the establishment of a PDU session via the S-NSSAI included in the 24th identification information received from the UE, they do not need to include a backoff timer value in the 37th identification information.

[0259] The 34th identification information may be the same as the 24th identification information.

[0260] Furthermore, if the network (e.g., SMF and / or NSACF) does not receive the 24th identification information, it may not include the 34th identification information in the control message, or it may send the 34th identification information indicating no S-NSSAI.

[0261] In addition, if the network (e.g., SMF and / or NSACF) does not receive the 25th identification information, it may not include the 35th identification information in the control message, or it may send the control message including the 35th identification information indicating no DNN.

[0262] By transmitting these identification information and / or PDU session establishment acceptance messages, the SMF and / or AMF and / or NSACF may indicate that the network supports each function, may indicate that the UE 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 are transmitted and received, two or more of these identification information may be configured as one or more identification information. Note that the information indicating support of each function and the information indicating a request for use of each function may be transmitted and received as the same identification information or as different identification information.

[0263] Furthermore, the SMF and / or AMF and / or NSACF may include the configured NSSAI, and / or the allowed NSSAI, and / or the rejected NSSAI, and / or the pending NSSAI in the PDU session establishment accept message and transmit it. Note that the identification information items 31 to 35 and 38 may be transmitted in such a manner that they are included in these NSSAIs, or may be transmitted as information separate from these NSSAIs.

[0264] The SMF and / or AMF and / or NSACF may notify the UE of the contents of these identification information by transmitting at least one of these identification information.

[0265] Furthermore, the SMF and / or AMF and / or NSACF may determine which identification information to include in the PDU session establishment acceptance message, and / or N1 SM container, and / or NAS message, and / or N2 SM information, and / or N2 PDU session request message based on each received identification information, and / or subscriber information, and / or network capability information, and / or UE policy, and / or operator policy, and / or network status, and / or user registration information, and / or information held by the SMF, and / or information held by the AMF, and / or information held by the NSACF, etc.

[0266] Next, when the UE receives the NAS message (S816), for example via the N1 interface, it can recognize that the UE's request via the PDU session establishment request message has been accepted and / or the contents of the information, etc. (message, container, information) contained in the NAS message.

[0267] Next, each step of the procedure in FIG. 7B will be explained.

[0268] First, based on receiving the PDU session establishment request message, the SMF sends an N1 SM container and / or a PDU session ID to the AMF, for example, via the N11 interface (S818), where the N1 SM container may include a PDU session establishment rejection message.

[0269] Next, the AMF that has received the N1 SM container and / or the PDU session ID transmits a NAS message to the UE via a base station device included in the access network (S820) (S822). Here, the NAS message is transmitted, for example, via an N1 interface. The NAS message may be a downlink NAS transport (DL NAS TRANSPORT) message. The NAS message may include the PDU session ID and / or the N1 SM container.

[0270] The PDU session establishment rejection message may be a response message to a PDU session establishment request, and may indicate that the establishment of the PDU session has been rejected.

[0271] Here, the SMF and / or AMF and / or NSACF may indicate that the UE's request via the PDU session establishment request message has been rejected by sending a PDU session establishment rejection message, and / or an N1 SM container, and / or a PDU session ID, and / or an NAS message.

[0272] Here, the SMF and / or AMF and / or NSACF may include at least one of the identification information items 31 to 38 in the PDU session establishment rejection message, the N1 SM container, and / or the NAS message and send it. Here, the identification information items 31 to 38 may be as described in Chapter 2.6.

[0273] By transmitting these identification information and / or PDU session establishment rejection messages, the SMF and / or AMF and / or NSACF may indicate that the network does not support each function, may indicate that the UE request has been rejected, may indicate that the UE request has not been authorized, or may indicate a combination of these. 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. Note that the information indicating support of each function and the information indicating a request for use of each function may be transmitted and received as the same identification information or as different identification information.

[0274] In addition, when the SMF and / or NSACF receives a PDU session establishment request message and rejects the PDU session establishment request due to rejection reason 2, the network (e.g., SMF and / or NSACF) may set the 36th identification information to indicate that the maximum number of PDU sessions per NS has been exceeded, and / or the maximum number of PDU sessions per NS has been reached, and / or the NS-related quota for the maximum number of PDU sessions has been exceeded, and / or congestion has occurred, and / or redirection to EPC is required (Redirection to EPC required), and / or no network slices are available, and / or insufficient resources for a specific NS and DNN (Insufficient resources for a specific slice).

[0275] In this case, the network (e.g., SMF and / or NSACF) may take into account the UE's S1 mode capability to determine whether to reject using the 36th identity.

[0276] In addition, the SMF and / or NSACF may include the 36th identification information if they do not allow (reject) the UE's request because it falls under rejection reason 2, or if they do not allow (reject) the establishment of a PDU session via the S-NSSAI included in the 24th identification information received from the UE.

[0277] In addition, if the SMF and / or NSACF does not allow (rejects) the UE's request because it falls under rejection reason 2, or if it does not allow (rejects) the establishment of a PDU session via the S-NSSAI included in the 24th identification information received from the UE, it may include a backoff timer value in the 37th identification information.

[0278] The 34th identification information may be the same as the 24th identification information.

[0279] Furthermore, if the network (e.g., SMF and / or NSACF) does not receive the 24th identification information, it may not include the 34th identification information in the control message, or it may send the 34th identification information indicating no S-NSSAI.

[0280] In addition, if the network (e.g., SMF and / or NSACF) does not receive the 25th identification information, it may not include the 35th identification information in the control message, or it may send the control message including the 35th identification information indicating no DNN.

[0281] The SMF and / or NSACF may also include the configured NSSAI, and / or the allowed NSSAI, and / or the rejected NSSAI, and / or the pending NSSAI in the PDU session establishment accept message and transmit it. Note that the identification information items 31 to 38 may be transmitted in these NSSAIs or may be transmitted as information separate from these NSSAIs.

[0282] The SMF and / or AMF and / or NSACF may notify the UE of the contents of these identification information by transmitting at least one of these identification information.

[0283] Furthermore, the SMF and / or AMF and / or NSACF may determine which identification information to include in the PDU session establishment rejection message, and / or N1 SM container, and / or NAS message, and / or N2 SM information, and / or N2 PDU session request message based on each received identification information, and / or subscriber information, and / or network capability information, and / or UE policy, and / or operator policy, and / or network status, and / or user registration information, and / or information held by the SMF, and / or information held by the AMF, and / or information held by the NSACF, etc.

[0284] Next, when the UE receives the NAS message (S822), for example via the N1 interface, it can recognize that the UE's request via the PDU session establishment request message has been rejected and / or the contents of the information, etc. (message, container, information) contained in the NAS message.

[0285] In addition, the UE may regard the reception of the 36th identification information via non-3GPP access as an abnormal case. In addition, the UE may regard the reception of the 36th identification information via a cell belonging to an SNPN as an abnormal case.

[0286] In addition, when the UE receives the 36th identification information, the UE may set the 5GS update status (also referred to as 5U status) of the UE to 5U3 ROAMING NOT ALLOWED.

[0287] In addition, when the UE receives the 36th identification information, the UE may delete all 5G-GUTIs, previously registered TAIs, TAI lists, etc. Furthermore, the UE may reset a registration attempt counter.

[0288] Furthermore, when the UE receives the 36th identification information, if the E-UTRA capability is in a disabled state, the UE may enable the E-UTRA capability, may disable the N1 mode capability for 3GPP access, or may transition to a 5GMM-DERIGISTERED.NO-CELL-AVAILABLE state.

[0289] Furthermore, if the UE receives the 36th identity via 3GPP access, the UE is operating in single registration mode, and the Attach procedure in EPS is rejected using the 36th identity, the UE may operate using an EMM state, an EPS update status, a 4G-GUTI, an attach attempt counter, etc. That is, the UE may operate using 4G parameters instead of 5G parameters.

[0290] Also, if the UE receives the 36th identity via 3GPP access, the UE is operating in single registration mode, and a tracking area update procedure in EPS is rejected using the 36th identity, the UE may operate using an EMM state, an EPS update status, a 4G-GUTI, a tracking area updating attempt counter, etc. That is, the UE may operate using 4G parameters instead of 5G parameters.

[0291] Also, if the UE receives the 36th identification information and disables the N1 mode capability, and if the lower layers of the UE do not provide information that the current E-UTRA cell is connected to the EPC, the UE may search for a suitable E-UTRA cell to connect to the EPC.

[0292] Also, if the UE receives the 36th identification information and disables the N1 mode capability, and if the lower layers of the UE provide information that the current E-UTRA cell is connected to the EPC, it may perform core network selection to select the EPC.

[0293] Furthermore, if the UE receives the 36th identification information and disables the N1 mode capability, and the lower layers of the UE cannot find an E-UTRA cell connecting to the EPC, the UE may indicate to the lower layers that it will continue to camp on the E-UTRA cell connecting to the 5GC, may start a timer, or may transition to the 5GMM-REGISTERED.LIMITED-SERVICE state.

[0294] Furthermore, when the UE receives the 34th identification information, and / or the 36th identification information, and / or the 37th identification information, it may recognize that the use of the S-NSSAI indicated by the 34th identification information is not permitted (rejected), and / or the establishment of a PDU session is not permitted (rejected), and / or the UE's request is not permitted (rejected).

[0295] Furthermore, when the UE receives the 34th identification information, and / or the 36th identification information, and / or the 37th identification information, it may recognize that the reason why the use of the S-NSSAI indicated by the 34th identification information was not permitted (rejected), and / or the reason why the establishment of the PDU session was not permitted (rejected), and / or the reason why the UE's request was not permitted (rejected) is based on the information indicated by the 36th identification information.

[0296] Furthermore, when the UE receives the 34th identification information, and / or the 36th identification information, and / or the 37th identification information, the UE may set a back-off timer value indicated by the 37th identification information to a timer that the UE has and that corresponds to the S-NSSAI indicated by the 34th identification information, and start the timer. The UE may not be able to transmit an MM message and / or an SM message for the S-NSSAI while the timer corresponding to the S-NSSAI indicated by the 34th identification information is running. The UE may be able to transmit an MM message and / or an SM message for the S-NSSAI when the timer corresponding to the S-NSSAI indicated by the 34th identification information expires. Note that the UE may transmit an MM message and / or an SM message for an S-NSSAI other than the S-NSSAI even if the timer corresponding to the S-NSSAI indicated by the 34th identification information is running.

[0297] Furthermore, the UE may determine, based on receiving the 34th identification information, and / or the 36th identification information, and / or the 37th identification information, and / or the 38th identification information, to communicate via E-UTRAN and / or EPC and / or EPS, or to perform a system change from N1 mode to S1 mode, or to change from communication using 5G to communication using 4G. In this case, the UE may perform an attach procedure and / or a tracking area update procedure in the EPS.

[0298] Furthermore, even if the UE performs an attach procedure and / or a tracking area update procedure in the EPS, the UE may continue or stop the operation of the timer corresponding to the S-NSSAI indicated by the 34th identification information. If the UE continues the operation of the timer corresponding to the S-NSSAI indicated by the 34th identification information, the UE may not be able to transmit an MM message and / or an SM message for that S-NSSAI in 5GS until the timer expires. Then, when the timer expires, the UE may be able to transmit an MM message and / or an SM message for that S-NSSAI in 5GS. If the UE stops the operation of the timer corresponding to the S-NSSAI indicated by the 34th identification information, the UE may be able to transmit an MM message and / or an SM message for that S-NSSAI in 5GS.

[0299] The UE may also start a timer to release the NAS signaling connection if it receives a registration reject message containing the 36th identification information.

[0300] Furthermore, if the UE does not receive the 34th identification information or receives the 34th identification information indicating no S-NSSAI, the UE may recognize that the above operation is for no S-NSSAI.

[0301] Furthermore, if the UE does not receive the 35th identification information or receives the 35th identification information indicating no DNN, the UE may recognize that the above operation is for no DNN.

[0302] Each device may complete this procedure based on sending and receiving a PDU session establishment acceptance message. At this time, each device may transition to a state in which it can communicate with the DN using the established PDU session.

[0303] Each device may complete this procedure based on sending and receiving a PDU session establishment acceptance message or a PDU session establishment rejection message. At this time, each device cannot establish a PDU session, and therefore cannot communicate with the DN if there is no already established PDU session.

[0304] In addition, each of the processes performed by the UE based on the reception of each identification information 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.

[0305] Each device may complete this procedure based on sending and receiving a PDU session establishment acceptance message. At this time, each device may transition to a state in which it can communicate with the DN using the newly established PDU session.

[0306] Each device may complete this procedure based on sending and receiving a PDU session establishment rejection message. At this time, each device cannot establish a new PDU session, and therefore cannot communicate with the DN if there is no already established PDU session.

[0307] In addition, each of the processes performed by the UE based on the reception of each identification information 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.

[0308] 4. Variations A program running on an apparatus according to the present invention may be a program that controls a central processing unit (CPU) or the like to cause a computer to function so as to realize the functions of an embodiment 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.

[0309] A program for implementing the functions of the embodiments of the present invention may be recorded on a computer-readable recording medium. The program may be loaded into a computer system and executed. The term "computer system" as used herein refers to a computer system built into a device, including hardware such as an operating system and peripheral devices. The term "computer-readable recording medium" may refer to a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a medium that dynamically stores a program for a short period of time, or any other computer-readable recording medium.

[0310] Additionally, each functional block or feature of the device used in the above-described embodiments may be implemented or performed by an electrical circuit, such as an integrated circuit or multiple integrated circuits. The electrical 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 electrical circuit may be composed of digital circuits or analog circuits. Furthermore, as advances in semiconductor technology emerge, one or more aspects of the present invention may utilize new integrated circuit technologies that replace current integrated circuits.

[0311] The present invention is not limited to the above-described embodiment. Although one example of a device has been described in the embodiment, the present invention is not limited to this and can be applied to stationary or non-movable electronic devices installed indoors or outdoors, such as terminal devices or communication devices for AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0312] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the invention. Furthermore, the present invention is susceptible to various modifications 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. Furthermore, configurations in which elements described in the above embodiments are substituted with elements that achieve the same effect are also included. [Explanation of symbols]

[0313] 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

[Claim 1] A UE (User Equipment) including a transceiver unit and a control unit, When the transceiver unit receives from the base station device a registration rejection message including an S-NSSAI (Single Network Slice Selection Assistance Information) exceeding the maximum number of PDU sessions per network slice, a reason value indicating that the maximum number of UEs per network slice has been exceeded, a back-off timer value, and a Pending NSSAI (Network Slice Selection Assistance Information), The control unit storing the S-NSSAI; Set the 5GS update status to 5U3 ROAMING NOT ALLOWED, Delete all 5G-GUTI and TAI lists, Reset the registration attempt counter, The back-off timer value indicates a period during which the UE is prohibited from returning to the N1 mode when the UE changes the system from the N1 mode to the S1 mode, The Pending NSSAI is a set of one or more S-NSSAIs for which network slice specific authentication has not been completed and which are unavailable in the current PLMN. A UE characterized by:

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