User equipment (UE)

Abstract

Provided are: a means for executing, in satellite-routed communication between a network and UE, with a store-and-forward function taken into account, management of a timer for transmitting / receiving appropriate control information between the network and the UE so as to retransmit an appropriate control message based on the control information between the network and the UE, management of the number of times a message is retransmitted, and retransmission of appropriate messages; and a method for executing appropriate processing based on the control information.

Description

UE (User Equipment)

[0001] The present invention relates to UE (User Equipment). This application claims priority to Japanese Patent Application No. 2024-002441, filed on January 11, 2024, the contents of which are incorporated herein by reference.

[0002] The 3GPP (3rd Generation Partnership Project: registered trademark) 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 to 4). In Release 19 of the 5G standard, the architecture for 5G communication via satellites (also simply referred to as "satellites"), communication and control procedures, etc. are being studied (see Non-Patent Document 4).

[0003] 3GPP TS 23.501 V18.4.0 (2023-12); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System architecture for the 5G System (5GS); Stage 2 (Release 18)3GPP TS 23.502 V18.4.0 (2023-12); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Procedures for the 5G System (5GS); Stage 2 (Release 18)3GPP TS 24.501 V18.5.0 (2023-12); 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3; 23.700-29 V0.2.0 (2023-11); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Study on integration of satellite components in the 5G architecture; Phase 3; (Release 19)

[0004] In the 5G System (5GS), a new core network called 5G Core Network (5GCN) is being considered to provide a wide variety of services. In addition, an architecture for 5G communication via satellites (also simply called "satellites") is being considered.

[0005] Currently, in such communication architectures that use satellites as a wireless technology (radio access technology) connecting user equipment (UE) and core networks, studies are underway on extending existing procedures, messages, or parameters that take into account the characteristics of wireless connections via satellite. More specifically, for example, new functions being considered for 5G communication via satellite include equipping satellites with base station functions, supporting store-and-forward functions by satellites and UEs, and supporting UE-satellite-UE communication.

[0006] On the other hand, when implementing the store-and-forward function by the satellite and UE, the behavior and processing of the UE and each device regarding the transmission and reception of control information between the UE and the satellite, the period for storing control information and / or user data transmitted and received from the UE or the network in the satellite, and the handling of the control information transferred after storage are not clear.

[0007] One aspect of this embodiment has been made in consideration of the above circumstances, and its purpose is to provide a method for, when a UE, a satellite, and a network that support a store-and-forward function execute each procedure for session management using the store-and-forward function, to send and receive appropriate control information between the network and the UE, taking into account the store-and-forward function, and to perform appropriate message retransmission and timer management based on the control information, thereby properly executing and completing each procedure for session management without interruption.

[0008] One aspect of a UE (User Equipment) of this embodiment is a UE having a transceiver unit, a control unit, and a memory unit, wherein the transceiver unit transmits capability information to a network indicating that the UE supports a store-and-forward function and receives first information from the network indicating that the network uses the store-and-forward function, and the control unit, based on the first information, does not abort the PDU session establishment procedure even if the transmission of a PDU (Protocol Data Unit) session establishment request message by the transceiver unit and the start and expiration of a first timer associated with the transmission of the PDU session establishment request message are repeated five or more times, but continues until a response message is received from the network. A UE (User Equipment) according to one aspect of the present embodiment is a UE including a transceiver unit, a control unit, and a storage unit, wherein the transceiver unit transmits capability information indicating that the UE supports a store-and-forward function and one or more S-NSSAIs (Single Network Slice Selection Assistance Information) supporting communication using the store-and-forward function to a network in a requested NSSAI (Network Slice Selection Assistance Information), receives from the network an allowed NSSAI including first information indicating that the network uses the store-and-forward function and one or more S-NSSAIs supporting communication using the store-and-forward function, and transmits a Protocol Data Unit (PDU) to the S-NSSAI supporting the store-and-forward function included in the allowed NSSAI. When executing a PDU session establishment procedure, the control unit, based on the first information, does not terminate the PDU session establishment procedure even if the transmission of a PDU session establishment request message by the transceiver unit and the start and expiration of a first timer associated with the transmission of the PDU session establishment request message are repeated five or more times, but continues to repeat the procedure until a response message is received from the network.

[0009] According to one aspect of this embodiment, in each procedure for session management when a UE and a network communicate via a satellite using a store-and-forward function provided by the satellite, there is provided a means for transmitting and receiving appropriate control information between the network and the UE, performing appropriate timer management based on the control information, and / or performing appropriate message retransmission, and a method for performing appropriate processing based on the control information.

[0010] FIG. 1 is a diagram illustrating an overview of a mobile communication system (EPS / 5GS). FIG. 2 is a diagram illustrating a detailed configuration of a mobile communication system (EPS / 5GS). FIG. 3 is a diagram illustrating the device configuration of a UE. FIG. 4 is a diagram illustrating the configuration of an access network device (gNB) in 5GS. FIG. 5 is a diagram illustrating the configuration of a core network device (AMF / SMF / UPF) in 5GS. FIG. 6 is a diagram illustrating a registration procedure. FIG. 7 is a diagram illustrating a session management procedure.

[0011] Hereinafter, a best mode for carrying out one aspect of this embodiment will be described with reference to the drawings. In this embodiment, as an example, an embodiment of a mobile communication system to which one aspect of this embodiment is applied will be described.

[0012] [1. System Overview] First, FIG. 1 is a diagram for explaining an overview 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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 Node Bs) 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.

[0021] 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).

[0022] 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.

[0023] 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.

[0024] 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).

[0025] 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.

[0026] Furthermore, in this specification, core network _A, and / or core network _B, and / or devices included in core network _A, and / or devices included in core network _B may be referred to as core networks, or core network devices, or devices within core networks, or networks, or NWs. In other words, for example, when referring to networks or NWs in this specification, it may mean core network _A or core network _B.

[0027] 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).

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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 portion. The payload portion 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.

[0032] 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).

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The UPF_A235 is connected to the DN, the SMF, other UPFs, and the access network. The UPF_A235 may perform functions such as anchoring for intra-RAT or inter-RAT mobility, packet routing and forwarding, an UL CL (Uplink Classifier) ​​function that supports routing of multiple traffic flows for one DN, a branching point function that supports multi-homed PDU sessions, QoS processing for the user plane, verification of uplink traffic, buffering of downlink packets, and a trigger function for downlink data notification. The UPF_A235 may also be a relay device that forwards user data as a gateway between the DN and the core network_B190. The UPF_A235 may also be a gateway for IP communication and / or non-IP communication. The UPF_A235 may also have the function of forwarding IP communication and the function of converting non-IP communication to IP communication. Furthermore, multiple gateways may be gateways that connect the core network _B190 to a single DN. Note that UPF_A235 may have connectivity with other NFs and may be connected to each device via other NFs.

[0037] Between UPF_A235 and the access network, UPF_C239 (also called a branching point or uplink classifier), which is a UPF different from UPF_A235, may exist as a device or NF. When UPF_C239 exists, a PDU session between the UE and the DN will be established via the access network, UPF_C239, and UPF_A235.

[0038] Furthermore, the UPF 130 may be the same device as the UPF_A 235. Note that the UPF 130 and the UPF_A 235 may be written with the symbols omitted, such as UPF.

[0039] [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.

[0040] 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 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.

[0041] [2.1. Device configuration of UE] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] The memory unit _A340 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the UE.

[0046] [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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The memory unit _B540 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the gNB.

[0052] [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. The AMF may also be a network device. In other words, for example, in this specification, a network device may mean an AMF.

[0053] 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 needed.

[0054] 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. That is, the AMF can use the network connection unit _B720 to transmit and receive user data and / or control information between a base station device (gNB), and / or SMF, and / or PCF, and / or UDM, and / or SCEF in a 5G AN. In other words, for example, the network connection unit may be a transceiver unit.

[0055] 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.

[0056] The memory unit _B740 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the AMF.

[0057] The AMF has functions such as exchanging control messages with the RAN using the N2 interface, exchanging NAS messages with the UE using the N1 interface, encrypting and protecting the integrity of NAS messages, registration management (RM) functions, connection management (CM) functions, reachability management functions, mobility management functions for UEs, etc., transferring SM (Session Management) messages between the UE and the SMF, access authentication (Access Authorization) functions, security anchor functionality (SEA), security context management (SCM), a function to support the N2 interface for the N3IWF (Non-3GPP Interworking Function), a function to support sending and receiving NAS signals with the UE via the N3IWF, and a function to authenticate UEs connected via the N3IWF.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] [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.

[0067] 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 needed.

[0068] 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.

[0069] 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.

[0070] The memory unit _B740 is a functional unit for storing programs, user data, control information, etc. required for each operation of the SMF.

[0071] 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.

[0072] [2.5. UPF Device Configuration] Next, an example of the UPF device configuration 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.

[0073] 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 needed.

[0074] 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.

[0075] 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.

[0076] The memory unit _B740 is a functional unit for storing programs, user data, control information, etc. required for each operation of the UPF.

[0077] 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.

[0078] 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.

[0079] 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 or a PDU session. Furthermore, in the case of EPS, the user plane may be transmitted and received using the LTE-Uu interface, and / or the S1-U interface, and / or the S5 interface, and / or the S8 interface, and / or the SGi interface. Furthermore, in the case of 5GS, the user plane may be transmitted and received via 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.

[0080] 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.

[0081] 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.

[0082] [2.6. Description of Other Devices and / or Functions] Next, other devices and / or functions will be described.

[0083] The PCF has a function to provide policy rules.

[0084] The UDM also has functions such as authentication credential processing, user identification processing, access authentication, registration / mobility management, and subscription management.

[0085] The PCRF is connected to the PGW and / or PDN and has a function of managing QoS for data delivery. For example, it manages the QoS of the communication path between the UE_A10 and the PDN. Furthermore, the PCRF may be a device that creates and / or manages PCC (Policy and Charging Control) rules and / or routing rules used by each device when transmitting and receiving user data.

[0086] The HSS is connected to the MME and / or SCEF and has a function of managing subscriber information. The subscriber information of the HSS is referred to, for example, when controlling access to the MME. Furthermore, the HSS may be connected to a location management device different from the MME.

[0087] [3. Explanation of Terms and Identification Information Used in Each Embodiment] Next, highly specialized terms and identification information used in each embodiment will be explained in advance.

[0088] [3.1. Explanation of Terms Used in Each Embodiment] Next, highly specialized terms used in each embodiment will be explained.

[0089] 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.

[0090] An SM (Session Management) message (also referred to as a NAS (Non-Access-Stratum) SM message) may be a NAS message used in a procedure for SM (SM procedure), and may be a control message transmitted and received between UE_A10 and SMF_A230 via AMF_A240. Furthermore, the SM message may include a PDU session establishment request message, a PDU session establishment accept message, a PDU session establishment reject message, a PDU session modification request message, a PDU session modification command message, a PDU session modification complete message, a PDU session modification command reject message, a PDU session modification reject message, a PDU session release request message, a PDU session release reject message, a PDU session release command message, a PDU session release complete message, etc. Furthermore, the procedure for SM or the SM procedure may include a PDU session establishment procedure, a PDU session modification procedure, and a UE-requested PDU session release procedure.Each procedure may be initiated from the UE or from the NW.

[0091] 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. Furthermore, the procedures for MM or MM procedures may include a registration procedure, a de-registration procedure, a generic UE configuration update procedure (also simply referred to as a UE configuration update procedure), an authentication and / or authorization procedure, a service request procedure, a paging procedure, and a notification procedure.

[0092] The 5GS (5G System) service is a connection service provided using the core network _B190. Furthermore, the 5GS service may be a service different from the EPS service or a service similar to the EPS service.

[0093] Non-5GS services may be services other than 5GS services, and may include EPS services and / or non-EPS services.

[0094] 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.

[0095] A PDU (Protocol Data Unit / Packet Data Unit) session can be defined as an association between a DN that provides PDU connectivity services 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. Note that each device (UE, and / or access network device, and / or core network device) may manage one or more pieces of identification information associated with a PDU session. Note that this identification information may include one or more of a DNN, a QoS rule, a PDU session type, an application identification information, an NSI identification information, an access network identification information, and an SSC mode, or may further include other information. Furthermore, when multiple PDU sessions are established, the identification information associated with each PDU session may be the same or different.

[0096] The DNN (Data Network Name) may be identification information that identifies the 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 a PGW / UPF that connects the core network_B190. Furthermore, the DNN may be equivalent to an APN (Access Point Name).

[0097] The PDU (Protocol Data Unit / Packet Data Unit) session type indicates the type of PDU session, and can be IPv4, IPv6, Ethernet, or Unstructured. If IPv4 is specified, it indicates that data will be sent and received using IPv4. If IPv6 is specified, it indicates that data will be sent and received using IPv6. If Ethernet is specified, it indicates that Ethernet frames will be sent and received. Ethernet may also indicate that communication using IP is not performed. If Unstructured is specified, it indicates that data will be sent and received to an application server or the like in the DN using Point-to-Point (P2P) tunneling technology. As the P2P tunneling technology, for example, UDP / IP encapsulation technology may be used. In addition to the above, the PDU session type may also include IP. IP can be specified if the UE is capable of using both IPv4 and IPv6.

[0098] 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 communication service provider, 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, a UE may store an Equivalent HPLMN list (also referred to as equivalent HPLMN) in its USIM to identify one or more EPLMNs (Equivalent HPLMNs). A PLMN 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).

[0099] 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. Note that 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.

[0100] 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.

[0101] The Current TAI is the TAI broadcast by the selected PLMN in the cell where the UE is located or camped, or if the cell is a satellite NG-RAN cell that broadcasts multiple Tracking Area Codes (TACs) in the selected PLMN, the UE NAS layer may select the current TAI from multiple Tracking Area Codes (TACs) in the selected PLMN.

[0102] The Lists of 5GS forbidden tracking areas may be a list of 5GS forbidden tracking areas for roaming and / or a list of 5GS forbidden tracking areas for regional provision of service stored by a UE not operating in an SNPN access operation mode. In other words, a UE not operating in an SNPN access operation mode must store a list of 5GS forbidden tracking areas for roaming and / or a list of 5GS forbidden tracking areas for regional service provision. Furthermore, the UE must search for a suitable cell within the same PLMN that belongs to a TA that is not included in the list of 5GS forbidden tracking areas.

[0103] Furthermore, a UE is not permitted to request 5GS services other than emergency services if it is located in a cell of a TA that belongs to the list of 5GS forbidden tracking areas for regional provision of service.

[0104] The UE may also store the forbidden tracking area ID (TAI) in a list of 5GS forbidden tracking areas for regional service provision to prevent repeated attempts to access cells in the forbidden tracking area. Furthermore, the list of 5GS forbidden tracking areas for regional service provision may be deleted when the UE is powered off, when the SIM is removed, or periodically (for a period ranging from 12 to 24 hours).

[0105] In addition, the information indicating the 5GS forbidden tracking areas for roaming may be included in an information element (IE) containing one or more forbidden TAI(s) for the list of "5GS forbidden tracking areas for roaming" included in a message sent by the network, and transmitted to the UE.

[0106] In addition, the 5GS forbidden tracking areas for regional provision of service may be included in an information element (IE) containing one or more forbidden TAIs for the list of "5GS forbidden tracking areas for regional provision of service" (5GS forbidden tracking areas for roaming) included in a message sent by the network and transmitted to the UE.

[0107] The UE ID is information for identifying a UE. 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.

[0108] An NTN (Non-terrestrial network) may be an NG-RAN consisting of multiple gNBs, which provides non-terrestrial NR access to UEs via NTN payloads and NTN gateways mounted on NTN transmission means such as satellites, aircraft, etc. installed in space or the air.

[0109] Here, the NTN payload is a network node mounted on a satellite or a high-altitude platform station and providing a connection function between a service link and a feeder link. Furthermore, the NTN payload may be a TNL (Transport Network Layer) node.

[0110] An NTN Gateway is an earth station installed on the Earth's surface that provides connectivity to the NTN payload using a feeder link, and may also be a TNL (Transport Network Layer) node.

[0111] In other words, for example, a "NR connection via satellite" (NR satellite access) by a UE may be an NR connection via a satellite (also simply referred to herein as a satellite) carrying an NTN payload and a gNB configured as an NTN gateway. Furthermore, the UE may perform procedures for registering with the network and / or establishing a PDU session via the NR connection, and may further perform communication using the established PDU session after completion of these procedures.

[0112] Herein, communication via an NTN is also referred to as communication via NR satellite access, or communication via an NTN, NTN communication, satellite communication, etc. Also, an NR connection via an NTN is also referred to as NR satellite access, or connection or access via a satellite, or satellite access, satellite radio access, etc.

[0113] A TN (terrestrial network) may provide terrestrial radio access to UEs through an access network configured with base stations and the like installed on the ground. In contrast to an NTN, which is a non-terrestrial network using satellites, a TN may be a terrestrial network. Furthermore, an access network installed and configured on the ground may be, for example, an NG-RAN configured with multiple gNBs, or an E-UTRAN configured with multiple eNBs, but is not limited to these.

[0114] Herein, communication via a TN is also referred to as communication via NR terrestrial access, or communication via a TN, TN communication, or non-satellite communication, etc. Also, NR connection via a TN is also referred to as NR terrestrial access, or connection or access via a non-satellite, or non-satellite access, etc.

[0115] The satellite NG-RAN Radio Access Technology (RAT) type may be information used to identify or distinguish different types of satellite NG-RAN access. The satellite NG-RAN RAT type may include, for example, "NR (LEO)," "NR (MEO)," "NR (GEO)," and "NR (OTHERSAT)." Here, "LEO" refers to a low earth orbit satellite, "MEO" refers to a medium earth orbit satellite, "GEO" refers to a geostationary earth orbit satellite, and "OTHERSAT" refers to other satellites.

[0116] Here, the access technology may be associated with a PLMN or SNPN. Further, a PLMN or SNPN may be capable of supporting multiple access technologies. Here, the UE may use the access technology information to determine the type of wireless carrier when selecting a particular PLMN or SNPN.

[0117] The AMF may also determine the RAT type of NR satellite access, and if the UE is accessing NR using satellite access, an indication of the NR satellite access type may be provided on the N2 interface. Furthermore, for the serving PLMN to implement efficient mobility restrictions for NR access, the TA in which cells of each NR satellite RAT type are deployed must be different from the TAs of other different satellite RAT types and the TAs of terrestrial access RAT types. Furthermore, the AMF may initiate UE deregistration when it receives an N2 UE Context Release Request with a cause value indicating that the UE is not in the PLMN serving area.

[0118] Herein, communication via an NTN is also referred to as communication via NR satellite access, or communication via satellite access, or 5GSAT communication, or NTN communication, etc. Also, an NR connection via a satellite (i.e., an NTN) is also referred to as NR satellite access, or connection or access via a satellite, or satellite access, etc. Also, NR satellite access may be 3GPP access.

[0119] The NR satellite access coverage provided by a satellite or satellite constellation may be discontinuous, also referred to as discontinuous network coverage, discontinuous coverage, or NR satellite access discontinuous coverage. Here, discontinuous coverage may result, for example, from the satellite or satellite constellation moving over time relative to a particular location on Earth, resulting in discontinuities in the coverage that the satellite or satellite constellation can provide.

[0120] Furthermore, a UE connected to a network via NR satellite access providing such discontinuous coverage is expected to move back and forth between coverage and out-of-service areas over time. Therefore, each device of the UE and / or the network may support some or all of one or more functions, including controls, parameters, or procedures, for supporting the discontinuous network coverage provided by NR satellite access. Note that, here, "in-service" may refer to a coverage (area) where the UE can communicate with a satellite, or a coverage (area) where the UE can communicate via a satellite. Furthermore, "out-of-service" may refer to a coverage (area) where the UE cannot communicate with a satellite, or a coverage (area) where the UE cannot communicate via a satellite.

[0121] More specifically, the one or more features including controls, parameters, or procedures for supporting discontinuous network coverage provided by NR satellite access may include satellite coverage availability information, and / or a mobility pattern, and / or an unavailability period, and / or unavailability period support, and / or a type of unavailability period, and / or an unavailability period duration, and / or a start of an unavailability period, and / or overload control in the discontinuous coverage provided by NR satellite access, and / or a maximum waiting time for overload control in the discontinuous coverage, and / or a discontinuous coverage wait timer value for overload control in the discontinuous coverage. The information may include a back-off timer in discontinuous coverage provided by the NR satellite access, a back-off timer in discontinuous coverage provided by the NR satellite access, and / or timer offset information in discontinuous coverage provided by the NR satellite access, and / or a maximum time offset or a discontinuous coverage maximum NAS signaling wait time. These are described below.

[0122] Satellite coverage availability information may be location and time information related to the expected coverage availability of a satellite or satellite constellation that provides discontinuous coverage, where a UE may use the satellite coverage availability information for satellite access to support discontinuous coverage operation. The satellite coverage availability information may be provided to the UE from an external server via a PDU session or Short Message Service (SMS).

[0123] The AMF may also use satellite coverage availability information to support satellite access by UEs operating in discontinuous coverage. Furthermore, satellite coverage availability information may be provided to the AMF from O&M (Operation and Maintenance). Here, the satellite coverage availability information provided to the AMF may describe when and where satellite reception is available in a certain area. Furthermore, the satellite coverage availability information is not UE-specific, and the AMF may be applicable to any UE in the affected area. In other words, the satellite coverage availability information may be information about a location or time when satellite access provided by a satellite or a group of satellites (satellite constellations) is expected to be available for use by a UE. That is, the satellite coverage availability information may indicate whether a UE is expected to be in or out of coverage at the location and time indicated by the information.

[0124] The satellite coverage availability information may include, for example, information indicating the time and location at which each satellite is expected to be able to provide NR satellite access to terrestrial UEs. Alternatively, the satellite coverage availability information may include information indicating the time and location at which each satellite is able to provide NR satellite access to terrestrial UEs, and the time and location at which each satellite is unable to provide NR satellite access to terrestrial UEs. Note that terrestrial UEs do not necessarily refer to UEs that are strictly adjacent to the Earth's surface, but also include UEs that are not adjacent to the Earth's surface.

[0125] An unavailability period may be a period or time during which a UE is out of coverage (i.e., out of service) or is expected or assumed to be out of coverage in NR satellite access discontinuous coverage. Furthermore, the unavailability period may be synonymous with a UE out-of-coverage period, an unreachable period, or an unreachability period. Here, the unavailability period may include an unavailability period due to NR satellite access discontinuous coverage and an unavailability period not due to NR satellite access discontinuous coverage. Furthermore, the unavailability period may be interpreted as an unavailability period due to NR satellite access discontinuous coverage and / or an unavailability period not due to NR satellite access discontinuous coverage. The unavailability period may also be interpreted as an unavailability period duration.

[0126] In addition, an unavailability period that is not due to NR satellite access discontinuous coverage is a period during which the network (i.e., 5GS) becomes unavailable, for example, for several minutes, due to a specific event being performed by the UE at any time, such as an update of the OS being executed, an update of the modem firmware, or a silent reset of the modem.

[0127] Here, the UE may become unable to use application functions without prior notification from the NW and / or UE due to an unavailability period not dependent on discontinuous NR satellite access coverage, which may affect the operation of the application server and / or network that depends on the availability of the UE during that period. Therefore, the UE needs to adjust the unavailability period not dependent on discontinuous NR satellite access coverage between the network and / or application function. Note that the UE and / or network may transmit and receive information regarding the unavailability period to adjust the unavailability period not dependent on discontinuous NR satellite access coverage. Details will be described later.

[0128] Here, the unavailability period that is not dependent on discontinuous NR satellite access coverage may also be referred to as a conventional function related to the unavailability period. Note that in this specification, the conventional function related to the unavailability period may also be referred to as "support for an unavailability period that is not dependent on discontinuous NR satellite access coverage" to distinguish it from "support for an unavailability period due to discontinuous NR satellite access coverage" described later.

[0129] In addition, an unavailability period due to discontinuous NR satellite access coverage is a period during which a UE connected to an NR satellite access that provides discontinuous coverage is out of the range of the NR satellite access and is unable to use the network (i.e., 5GS) for, for example, several minutes.

[0130] Here, by considering, for example, ephemeris information and UE location information as information related to satellite orbits, it is possible to predict in advance whether NR satellite access can provide connectivity to a UE at a specific location on the Earth. That is, the UE and / or NW may be able to predict in advance the unavailability period due to discontinuous coverage of the NR satellite access from the ephemeris information and the UE location information. Note that the UE may receive the ephemeris information as broadcast information from the NR satellite access and / or as a control message or user data from the network.

[0131] Here, in an unavailability period not due to discontinuous NR satellite access coverage, it is assumed that this behavior is due to a specific small number of UEs, and after the period, the UEs can reconnect to the network and / or resume communication. On the other hand, in an unavailability period due to discontinuous NR satellite access coverage, it is assumed that excessive network unavailability may occur due to reconnection when a large number of UEs accommodated in the coverage of a cell provided by the NR satellite access return to the coverage provided by the NR satellite access after being unavailable for the period. For this reason, overload control is required that takes into account the load caused by a large number of UEs reconnecting to the network via the NR satellite access, which is assumed after the unavailability period due to discontinuous NR satellite access coverage. Overload control will be described later. In this way, the parameters, judgments, behaviors, etc. considered by the UE and / or the NW may differ depending on whether the unavailability period is due to discontinuous NR satellite access coverage.

[0132] In order to realize such an unavailability period function, information indicating the type of unavailability period, the duration of the unavailability period, and / or the start of the unavailability period is required to determine whether the unavailability period is due to discontinuous NR satellite access coverage. This information is described below.

[0133] Unavailability period support may be capability information indicating support for a function for using an unavailable period. More specifically, in a registration procedure, a UE that supports the unavailable period function may indicate Unavailability period support as part of capability information (5GMM Core Network Capability or 5GMM capability) in a registration request message for initial registration or every mobility registration (mobility registration or mobility registration update).

[0134] Note that support for unavailable periods may include support for unavailability periods using discontinuous NR satellite access coverage and support for unavailability periods not using discontinuous NR satellite access coverage. Specific details of the operation will be described later.

[0135] The information may indicate the type of unavailability period, whether the unavailability period is due to non-contiguous NR satellite access coverage, and / or whether the unavailability period is due to non-contiguous NR satellite access coverage. In other words, for example, the type of unavailability period may indicate that the unavailability period is due to non-contiguous NR satellite access coverage.

[0136] The unavailability period duration may be information indicating the duration of the unavailability period. Furthermore, a timer may be executed using the unavailability period duration as a timer value. Here, the unavailability period duration may be information associated with the type of the unavailability period, and the UE and / or NW may transmit or store the unavailability period duration in association with the type of the unavailability period.

[0137] The start of the unavailability period may be information indicating a timing or time that specifies the start of the unavailability period. More specifically, for example, the start of the unavailability period may be information indicating a timing or time at which an unavailability period due to discontinuous NR satellite access coverage starts. Note that the start of the unavailability period may be information that is not used in an unavailability period that is not due to discontinuous NR satellite access coverage, or may be information that is used. Furthermore, the start of the unavailability period may be received and stored by the UE by broadcast information from the NR satellite access and / or a message from the NW. Furthermore, the start of the unavailability period may be information that is associated with the type of unavailability period, or may not be associated with the type of unavailability period.

[0138] Here, the UE out-of-coverage period may be determined based on satellite coverage information and a UE mobility pattern. The UE out-of-coverage period may be synonymous with the unavailability period, and the UE out-of-coverage period described in this specification may be read as the unavailability period. Furthermore, the UE out-of-coverage period may be determined by the UE, or by the network or each network device. More specifically, for example, the UE may transmit the determined UE out-of-coverage period to the network, and the network or each network device may receive and store it.

[0139] In addition, for example, the network or any network device (e.g., AMF) may transmit the determined UE out-of-service period to the UE, the network, or another network device, and the UE, the network, or another network device may receive and store the determined UE out-of-service period. The UE out-of-service period is also referred to as a period during which the UE is out of service.

[0140] Here, the UE out-of-service period may be a period during which the UE is out of service, or may be a timer or timer value corresponding to the period during which the UE is out of service. Furthermore, the UE out-of-service period may be an unreachability period, or may be a period indicated by the unreachability period or a corresponding timer or timer value. Furthermore, for example, the unreachability period may be a timer or timer value included in the "Unreachability period duration IE." Furthermore, if the UE out-of-service period is a timer or timer value corresponding to the period during which the UE is out of service, the timer may be started when the UE transitions to an out-of-service state or an idle state (idle mode).

[0141] Furthermore, for example, the UE may use an existing timer or timer value corresponding to the UE out-of-coverage period, or may use a new timer different from the existing timer. More specifically, for example, the UE out-of-coverage period may be a timer or timer value included in a "UE out-of-coverage period duration information element (IE)." Furthermore, the "UE out-of-coverage period duration IE" may be an existing timer or timer value (e.g., GPRS Timer 3 IE), or may be information indicating a new timer or a new timer value for 5GSAT communication. Note that, for example, if the UE out-of-coverage period is an unreachability period, a timer or timer value indicating a period corresponding to the UE out-of-coverage period may be included in the "UE out-of-coverage period duration IE" and / or the "Unreachability period duration IE."

[0142] Furthermore, when the UE determines the UE out-of-service period, it may be based on satellite coverage availability information and a UE mobility pattern provided by the network, or on satellite coverage availability information and a UE mobility pattern maintained by the UE. For example, the UE may determine the UE out-of-service period based on satellite coverage availability information provided by the network and a UE mobility pattern provided by the network. Alternatively, for example, the UE may determine the UE out-of-service period based on satellite coverage availability information provided by the network and a UE mobility pattern maintained by the UE. Alternatively, for example, the UE may determine the UE out-of-service period based on, but not limited to, satellite coverage availability information maintained by the UE and a UE mobility pattern maintained by the UE.

[0143] Furthermore, for example, if the UE can determine the UE out-of-coverage period and decides to remain out of service for the period indicated by the UE out-of-coverage period, it may perform a Mobility Registration Update procedure before the start of the unreachability period. Furthermore, the UE may request a Mobile Initiated Connection Only (MICO) mode parameter, extended DRX (eDRX) parameter in CM-IDLE, or other NAS timer using a related procedure that takes into account the UE out-of-coverage period, and in this case, if the UE requests the use of MICO mode or eDRX, the UE out-of-coverage period may not be included. Alternatively, the UE may notify the network of the UE out-of-coverage period when it intends to leave satellite coverage, and may perform a Mobility Registration Update procedure when it returns to coverage via any access type.

[0144] The AMF may adjust the mobile reachable timer and / or the implicit unregistration timer so that the AMF does not implicitly deregister the UE during the UE's unavailability period.

[0145] Overload control in discontinuous coverage provided by NR satellite access is a control and / or function for avoiding excessive signal load on the network when a large number of UEs return from outside the coverage area of ​​the NR satellite access. Furthermore, overload control in discontinuous coverage may be control using a maximum waiting time, a Disco wait range, and / or a maximum time offset or a discontinuous coverage maximum NAS signaling wait time. Furthermore, the maximum waiting time may be a time determined by the AMF until a UE that has returned to the coverage area of ​​the satellite access is permitted to start NAS signaling with the network. In other words, for overload control, the AMF may determine the maximum waiting time until a UE is permitted to start NAS signaling with the network. Here, the maximum waiting time may be, for example, Disco wait range, and / or Maximum Time Offset, or Discontinuous coverage maximum NAS signaling wait time, and in this specification, unless otherwise specified, these may be synonymous.

[0146] More specifically, for example, in overload control in discontinuous coverage using a maximum latency, the AMF first determines a maximum latency based on network configuration, a prioritized user, or a prioritized service, and transmits the maximum latency to the UE during the registration procedure or the UE configuration update procedure. Next, if the UE that receives the maximum latency has already received a maximum latency for the same RAT type and PLMN, the UE may replace the stored or saved maximum latency. Furthermore, the UE that receives the maximum latency may select a random value as an upper limit for the maximum latency to determine a discontinuous coverage wait timer value. In other words, for example, if the UE has stored or saved a discontinuous coverage maximum NAS signaling latency for each PLMN and / or satellite NG-RAN RAT type, the UE may update the value to the latest value when it receives a discontinuous coverage maximum NAS signaling latency for the same PLMN and / or satellite NG-RAN RAT type combination.

[0147] Wherein, the discontinuous coverage waiting timer may be a timer that restricts the UE from connecting to the network via the satellite access, and the UE may execute the discontinuous coverage waiting timer based on a discontinuous coverage waiting timer value determined by the UE.

[0148] In addition, when a UE returns to NR satellite access coverage from outside the coverage area with the same RAT (Radio Access Technology) type and PLMN, it starts a discontinuous coverage wait timer. A UE running the discontinuous coverage wait timer must not start NAS signaling for that RAT type and PLMN. Through the above procedures and processes, multiple UEs returning to coverage area each run a discontinuous coverage wait timer with a different random value, thereby controlling and reducing excessive signal load on the network.

[0149] Here, the maximum waiting time determined by the AMF may be included in an MM message transmitted and received during an MM (Mobility Management) procedure and transmitted to the UE. More specifically, for example, the MM procedure in which the AMF transmits the maximum waiting time to the UE may be a registration procedure or a UE configuration update procedure. Furthermore, for example, the MM message in which the AMF includes the maximum waiting time may be, for example, a registration accept message, a registration reject message, or a configuration update command message. In other words, the maximum waiting time may be included in an MM message and transmitted from the AMF to the UE in an MM procedure such as a registration procedure or a UE configuration update procedure.

[0150] Also, if the UE has stored a discontinuous coverage maximum NAS signal latency due to discontinuous coverage, when it returns to coverage (i.e., in-range) after going out of coverage (i.e., out of range) of NR satellite access, the UE shall set the discontinuous coverage maximum NAS signal latency value to a random value up to the discontinuous coverage maximum NAS signal latency stored for this PLMN and satellite NG-RAN RAT type and start this timer. While the discontinuous coverage maximum NAS signal latency timer is running, the UE shall not initiate any NAS signals on that satellite NG-RAN RAT type and PLMN.

[0151] Furthermore, if the UE receives a paging message and there is an emergency service pending, or if the UE enters a TAI outside the registration area, the UE may stop the timer based on the non-contiguous coverage maximum NAS signaling latency and start NAS signaling.

[0152] Also, a UE, a network, or each device that uses a function related to maximum latency may support maximum latency. In other words, if a UE, a network, or each device supports maximum latency, for example, an AMF may have the capability to determine the maximum latency, or the UE may have the capability to select or determine a discontinuous coverage latency timer from the received maximum latency. In other words, a UE, a network, or each device that supports communication via NR satellite access may support maximum latency as a function for discontinuous coverage.

[0153] The back-off timer in discontinuous coverage provided by NR satellite access may be a timer provided by the AMF to the UE to prevent the initiation of Mobile Originated (MO) data transmission or signaling before the UE is about to go out of coverage.

[0154] In other words, the back-off timer for the discontinuous satellite coverage provided by the AMF to the UE may be started to end when the UE is in range based on the satellite coverage availability information (i.e., the coverage period of the NR satellite access), and while the timer is running, the UE may be prohibited from starting MO data transmission or signaling. Also, if the UE is still in the same satellite communication area after the timer expires, it may start MO data transmission or signaling, or if it finds a cell of another TN or NTN, it may stop the timer and register through a new access network and send MO data.

[0155] The AMF that provided the back-off timer to the UE may initiate the AN release procedure. Furthermore, the back-off timer in the discontinuous satellite coverage may use an existing timer or may be defined and used as a new timer.

[0156] The timer offset information in NR satellite access providing discontinuous coverage may be information indicating a timer offset value that is associated with a timer that runs while the UE is in coverage or a timer that runs while the UE is out of coverage, and that takes into account the coverage that the UE or the network recognizes based on satellite coverage availability information and a physical coverage gap due to UE movement, satellite orbit, etc. In this specification, the timer offset information in NR satellite access providing discontinuous coverage may also be referred to as timer offset information indicating a time or period, timer offset information, timer offset, offset information, or simply offset, etc.

[0157] Here, the offset information may be information or parameters preconfigured in the UE, determined by the UE, or determined by the network. More specifically, for example, the offset information may be information or parameters preconfigured in the UE. Alternatively, the offset information may be information or parameters determined by the network, transmitted to the UE, and stored by the received UE. Alternatively, the offset information may be information or parameters determined by the UE, transmitted to the network, and stored by the network or each device.

[0158] Furthermore, the timer offset information may be associated with one or more timers. That is, the same number of timer offset information may be associated with one or more timers, or one offset information may be associated with one or more timers. Here, the timer associated with the offset information may be information associated with a period or timer indicating a time during which the UE is in coverage corresponding to the satellite coverage availability information and / or a UE out-of-coverage period. More specifically, for example, the offset information may be an offset value of a timer used to specify a time to advance or delay the start or end of a timer corresponding to a period during which the UE is out of coverage or in coverage, taking into account discontinuous coverage in NR satellite access. In other words, for example, if the offset information indicates that the expiration time of a timer corresponding to a UE out-of-coverage period should be extended, the UE may start the timer based on a value obtained by adding the value of the offset information to the timer value.

[0159] In addition, a UE connected to a network via a TN or NTN and in a registered state (RM-REGISTERED state) may perform a Mobility Registration Update procedure if the current TAI of the serving cell is not included in the list of TAIs that the UE received from the network, in order to maintain the registration and enable the AMF to page the UE. Note that in this specification, the Mobility Registration Update procedure is also simply referred to as Mobility Registration Update.

[0160] Furthermore, if the UE is connected to the network, particularly via an NTN (i.e., NR satellite access), in addition to the above conditions for performing the mobility registration update procedure when connecting to the network via a TN or NTN, the following conditions shall be taken into account:

[0161] First, a moving radio cell for NR satellite access may be able to indicate support for one or more TACs per PLMN. Here, a UE registered in a PLMN can access a radio cell as long as at least one supported TAC of the RPLMN or an equivalent RPLMN is part of the UE registration area, and does not need to perform a mobility registration update procedure. Also, a UE must perform a mobility registration update procedure when accessing a radio cell in which none of the TACs supported by the RPLMN or an equivalent RPLMN is part of the UE registration area.

[0162] Furthermore, when the UE indicates the last accessed TAI in a mobility registration update, it may be able to indicate a TAI that is supported in the radio cell of the RPLMN or equivalent RPLMN that the UE last accessed before the registration update and is part of the UE registration area.

[0163] A serving satellite is a satellite that provides satellite access to a UE. For example, a serving satellite may provide a serving cell(s) to the UE. Depending on the satellite's orbit, the serving satellite may cover a geographic area for a limited period of time.

[0164] Store and Forward (S&F) satellite operation is an operation mode that provides communication services (storage and forwarding of information) to a UE during periods and / or geographic areas when the serving satellite is not simultaneously connected to a terrestrial network via a feeder link or Inter-Satellite Link (ISL). For uplink (UL; UE-to-satellite communication), "store" can refer to onboard storage of UL information from the UE, and "forward" can refer to forwarding of the "stored" UL information to the terrestrial network. For downlink (DL; satellite-to-UE communication), "store" can refer to onboard storage of DL information from the terrestrial network, and "forward" can refer to forwarding of the stored DL information to the UE.

[0165] In this specification, the communication service provided by store-and-forward satellite operation is also referred to as store-and-forward functionality, or store-and-forward, or S&F functionality, or communication in S&F mode, or S&F, etc. Furthermore, UEs, satellites, and networks that utilize the store-and-forward functionality may support the store-and-forward functionality.

[0166] UE-Satellite-UE communication may be communication between UEs within the coverage of one or more serving satellites using satellite access without user traffic passing through a terrestrial segment. In other words, UE-Satellite-UE communication may be communication between two UEs in which user data traffic transmitted and received between the UEs is transmitted and received via a single satellite or multiple satellites connected by an ISL, without going through a terrestrial core network.

[0167] [3.2. Description of Identification Information in Each Embodiment] Next, the identification information used in each procedure in each embodiment will be described.

[0168] In this embodiment, the first identification information is the capability information of the UE. The first identification information may be capability information indicating whether or not the UE supports communication using the store-and-forward function. Unless otherwise specified in this specification, the first identification information indicates that the UE supports communication using the store-and-forward function.

[0169] The first identification information may be information included as part of a 5GMM capability, a 5GMM capability Information Element (IE), or a 5GMM capability. Alternatively, the first identification information may be information included as part of a 5GSM capability, a 5GSM capability Information Element (IE), or a 5GSM capability.

[0170] Here, when the UE indicates the first identification information to the network, the network and each device may recognize that the UE supports communication using the store-and-forward function. Furthermore, the network may transition or activate the UE to a mode in which the UE performs communication that takes into account the use of the store-and-forward function or performs communication by the store-and-forward function.

[0171] Further details of the behavior of the UE and NW based on the first identification information are also described in Chapter 4 and / or Chapter 5.

[0172] In this embodiment, the second identification information may be one or more S-NSSAIs (Single Network Slice Selection Assistance Information) that support store-and-forwarding, or an NSSAI (Network Slice Selection Assistance Information) that includes an S-NSSAI that supports the store-and-forward function, as requested by the UE. In other words, the PDU session established for the S-NSSAI that supports the store-and-forward function may be an S-NSSAI that enables communication using the store-and-forward function.

[0173] Here, when the UE requests a network slice (S-NSSAI) supporting the store-and-forward function from the NW, the UE may transmit a message including the second identification information to the NW. More specifically, for example, the UE may request a network slice (S-NSSAI) supporting the store-and-forward function from the NW by including the second identification information in a requested NSSAI in a registration request message or by including the second identification information as a requested NSSAI in the registration request message.

[0174] Additionally, the UE may include second identification information in the message to indicate to the network that the UE supports the store-and-forward function and / or requests or prefers communication using the store-and-forward function.

[0175] Further details of the behavior of the UE and NW based on the second identification information are also described in Chapter 4 and / or Chapter 5.

[0176] The third identification information in this embodiment may be preference information indicating whether to use or not use the store-and-forward function, or may be information indicating a network behavior or operation that the UE prefers. In addition, the third identification information may be information indicating whether the UE supports or does not support the store-and-forward function.

[0177] Furthermore, the third identification information may be information included in a 5GS update type by the UE, and may also include information indicating a preference for using a store-and-forward function for each core network, such as 5GS and / or EPS.

[0178] Furthermore, the third identification information may be identification information that the UE includes in a message if the UE supports store-and-forward. And / or, the third identification information may be identification information that the UE includes in a message if the UE includes in the message first identification information indicating store-and-forward. And / or, if the UE includes in a message information indicating that store-and-forward is preferred, the network may recognize that the UE supports the store-and-forward function even if the UE does not include the first information in the message. And / or, the first identification information and the second identification information may be combined to indicate that the UE supports the store-and-forward function. In this specification, unless otherwise specified, the third identification information may be information indicating that the UE supports the store-and-forward function and / or information indicating the UE's preference for using the store-and-forward function.

[0179] The third identification information may be the same as or different from the content of the fifth identification information described below. More specifically, for example, the number and content of S-NSSAIs indicated by the third identification information may be the same as the number and content of S-NSSAIs indicated by the fifth identification information, or may be different in number and content, or the content of one or more S-NSSAIs indicated by the third identification information and the fifth identification information may be the same, or may be, but is not limited to, the above.

[0180] Further details of the behavior of the UE and NW based on the third identification information are also described in Chapter 4 and / or Chapter 5.

[0181] The fourth identification information in this embodiment is information indicating support of a network (NW) capability or function. The fourth identification information may be information indicating that the network or each device in the network supports or does not support communication using the store-and-forward function. Unless otherwise specified in the specification, the fourth identification information indicates that the UE supports communication using the store-and-forward function.

[0182] Furthermore, the fourth identification information may be information included as part of 5GS network feature support, a 5GS network feature support IE, or 5GS network feature support, or the fourth identification information may be information included as part of 5GSM network feature support, a 5GSM network feature support IE (Information Element), or 5GSM network feature support.

[0183] Here, when the NW indicates the fourth identification information to the network, the UE may recognize that the NW supports communication using the store-and-forward function. Furthermore, the UE that receives the fourth identification information from the NW may recognize that communication using the store-and-forward function is possible. Furthermore, the UE may execute communication that takes into account the NW's use of the store-and-forward function, or transition to or activate a mode in which communication using the store-and-forward function is executed.

[0184] Further details of the behavior of the UE and NW based on the fourth identification information are also described in Chapter 4 and / or Chapter 5.

[0185] The fifth identification information in this embodiment may be one or more S-NSSAIs supporting store-and-forward, or an NSSAI including an S-NSSAI supporting the store-and-forward function, which the NW indicates to the UE. Here, the PDU session established for the S-NSSAI supporting the store-and-forward function may be an S-NSSAI capable of communication using the store-and-forward function.

[0186] Also, here, when the NW indicates to the UE a network slice (S-NSSAI) supporting the store-and-forward function, the NW may transmit a message including the fifth identity to the UE. More specifically, for example, the NW may indicate to the UE a network slice (S-NSSAI) supporting the store-and-forward function by including the fifth identity in an allowed NSSAI in a registration accept message or by including the second identity in a registration accept message as an allowed NSSAI.

[0187] The fifth identification information may be the same as or different from the third identification information described below. More specifically, for example, the number and contents of S-NSSAIs indicated by the third identification information may be the same as the number and contents of S-NSSAIs indicated by the fifth identification information, or may be different in number and contents, or the contents of one or more S-NSSAIs indicated by the third identification information and the fifth identification information may be the same, or may be, but are not limited to, the above.

[0188] Further details of the behavior of the UE and NW based on the fifth identification information are also described in Chapter 4 and / or Chapter 5.

[0189] The sixth identification information in this embodiment may be indication information indicating that the UE and each device in the network use the store-and-forward function.

[0190] Here, it may mean that the sixth identification information applies to the SM procedure performed after the registration procedure is completed, and / or to the transmission and reception of user data between the UE and the network, based on the indication of the use of the store-and-forward function indicated by the sixth identification information.

[0191] Further details of the behavior of the UE and NW based on the sixth identification information are also described in Chapter 4 and / or Chapter 5.

[0192] The seventh identification information in this embodiment may be a timer value of a session management timer (SM timer) when the store-and-forward function is used. More specifically, for example, the SM timer may be each value of timers T3580, T3581, and / or T3582.

[0193] Here, the network or each device may determine whether to include the seventh identification information in the message based on whether the UE supports the store-and-forward function and / or whether communication between the UE and the network is possible using the store-and-forward function.

[0194] Furthermore, here, a UE that receives a message including the seventh identification information may replace or update an SM timer value that is already stored or preconfigured in the UE, or may store the SM timer value for communication using the store-and-forward function that is different from the normal SM timer value that is already stored, or may update the SM timer value for communication using the store-and-forward function that is different from the normal SM timer value preconfigured in the UE. Furthermore, if a UE that does not support the store-and-forward function receives a message including the seventh identification information from the network, the UE ignores the seventh identification information.

[0195] Furthermore, the conventional SM timer and conventional SM timer value may be the SM timer and SM timer value used in communication that does not use the store-and-forward function.

[0196] Further details of the behavior of the UE and NW based on the seventh identification information are also described in Chapter 4 and / or Chapter 5.

[0197] The above-mentioned first to seventh identification information may be included in a message as individual identification information, or may be included in a message as a single piece of information combining one or more of the first to seventh identification information. Furthermore, a single piece of information combining one or more of the first to seventh identification information may represent a combination of the matters indicated by the identification information described in this chapter. In other words, when multiple pieces of identification information are transmitted and received, two or more of these identification information may be configured as one or more pieces of identification information. Furthermore, the information indicating support for each function and the information indicating a request for use of the respective function may be transmitted and received as the same identification information, or may be transmitted and received as different identification information.

[0198] Details of the behavior of the UE and the network based on one or a combination of the above first to seventh identification information are not limited to those described in this chapter, but are also described in Chapter 4 and / or Chapter 5.

[0199] [4. Description of Procedures Used in Each Embodiment] Next, procedures used in each embodiment will be described. Here, the procedures used in each embodiment may include a registration procedure and various procedures for session management.

[0200] In each embodiment, as shown in FIG. 2, the HSS and UDM, PCF and PCRF, SMF and PGW-C, and UPF and PGW-U are each configured as the same device (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 where these are configured as different devices (i.e., different physical hardware, different logical hardware, or different software). For example, data may be transmitted and received directly between these devices, or data may be transmitted and received via the N26 interface between the AMF and MME, or data may be transmitted and received via the UE.

[0201] The registration procedure is explained in detail below.

[0202] [4.1. Registration Procedure] First, the registration procedure will be explained using Figure 6. The registration procedure is a procedure in 5GS. Hereinafter, in this section, this procedure refers to the registration 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 the network, it can execute this procedure at any time, for example, when powered on. In other words, if the UE is in the deregistered state (RM-DEREGISTERED state), it can start this procedure at any time. Furthermore, each device (especially the UE and AMF) can transition to the registered state (RM-REGISTERED state) based on the completion of the registration procedure.

[0203] The registration procedure may be an initial registration initiated by the UE, or a mobility and periodic registration update, or a mobility registration update procedure. Here, the mobility registration update procedure may also be referred to as a registration procedure for mobility update. These registration procedures may also be MM procedures.

[0204] 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, or may be a mobility registration update procedure performed after the completion of the initial registration procedure and the expiration of the unavailability period to resume normal service.

[0205] This procedure may also be a procedure for registration by a UE via NR satellite access. Furthermore, the PDU session established after completion of this procedure may be a PDU session via the satellite NG-RAN or NR satellite access. In other words, for example, a PDU session established by a PDU session establishment procedure performed after completion of the registration procedure via NR satellite access may be a PDU session via NR satellite access. Alternatively, for example, a PDU session via NR satellite access may be established based on completion of this procedure.

[0206] A UE may initiate a registration procedure when performing mobility across TAs. More specifically, a UE may initiate a Mobility Registration Update procedure to re-register when it moves to a TA different from the TA indicated in the TA list it holds. Furthermore, a UE may initiate this procedure when a running timer expires. Furthermore, a UE may initiate a registration procedure when a context update for each device is required due to a PDU session disconnection or invalidation. Furthermore, a UE may initiate a registration procedure when a change occurs in the capability information and / or preferences related to the establishment of a PDU session. Furthermore, a UE may initiate a registration procedure periodically. Furthermore, a UE may initiate a registration procedure based on the completion of a UE Configuration Update procedure. However, the UE may perform the registration procedure at any timing, not limited to these.

[0207] Furthermore, even when the UE is in a registered state, the UE may periodically initiate the registration procedure. In other words, the UE may initiate the registration procedure based on the expiration of a timer. In other words, the registration procedure performed periodically may be a periodic registration update procedure.

[0208] The registration procedure performed based on the mobility of the UE and the registration procedure performed periodically are also referred to as a registration procedure for mobility and registration update or a registration update procedure. In other words, the registration procedure for mobility and registration update may be a registration procedure performed based on the mobility of the UE, or may be a registration procedure performed periodically. Furthermore, the registration procedure for mobility and registration update may be a registration procedure performed based on a configuration update of the UE. Furthermore, the registration procedure for mobility and registration update may be a registration procedure performed to establish a communication path for transmitting and receiving user data. Furthermore, the registration procedure for mobility and registration update may be a registration procedure performed based on a request from the network. Furthermore, in other words, the registration procedure for mobility and registration update may be a registration procedure other than the initial registration procedure. Hereinafter, the registration procedure for mobility and registration update may be referred to as the main procedure.

[0209] Next, each step of the registration procedure will be described. Note that the registration procedure described below may be an initial registration procedure or a registration procedure for mobility and registration renewal.

[0210] First, the UE starts the registration procedure by sending a registration request message to the AMF (S600) (S602) (S604). Specifically, the UE sends an RRC message including a registration request message to the 5G AN (or gNB) (S600). The registration request message is a NAS message. The RRC message may be a control message transmitted and received between the UE and the 5G AN (or gNB). The NAS message is processed in the NAS layer, and the RRC message is processed in the RRC layer. The NAS layer is a layer higher than the RRC layer.

[0211] Here, the UE may transmit the registration request message by including any one or more of the first to third identification information in the message.

[0212] Furthermore, when multiple pieces of identification information are transmitted and received, two or more of these 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 for use of the function may be transmitted and received as the same identification information, or may be transmitted and received as different identification information.

[0213] The UE may also initiate the PDU session establishment procedure during the registration procedure by sending an SM message included in or together with a registration request message, where the SM message may be a PDU session establishment request message.

[0214] When a 5G AN (or gNB) receives an RRC message including a registration request message, it selects an AMF to which to forward the registration request message (S602). Note that the 5G AN (or gNB) can select an AMF based on information included in the registration request message and / or the RRC message. The 5G AN (or gNB) extracts the registration request message from the received RRC message and forwards the registration request message to the selected AMF (S604).

[0215] The AMF that receives the registration request message from the UE may recognize and store the meaning of the identification information included in the registration request message.

[0216] When the AMF receives the registration request message, the AMF can perform a first condition determination. The first condition determination is for determining whether the network (or the AMF) accepts the UE's request. If the first condition determination is true, the AMF starts the procedure of (A) in Figure 6, while if the first condition determination is false, the AMF starts the procedure of (B) in Figure 6.

[0217] The first condition determination may be performed based on the reception of a registration request message, and / or each identification information included 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 a context held by the AMF, etc. For example, if the network permits the UE's request, the first condition determination may be true, and if the network does not permit the UE's request, the first condition determination may be false. Furthermore, if the network to which the UE is registered and / or a device within the network supports a function requested by the UE, the first condition determination may be true, and if the function requested by the UE is not supported, the first condition determination may be false. Furthermore, if the identification information to be transmitted and received is permitted, the first condition determination may be true, and if the identification information to be transmitted and received is not permitted, the first condition determination may be false. The conditions for determining whether the first condition determination is true or false do not have to be limited to the above-described conditions.

[0218] First, we will explain the case where the first condition determination is true. In the procedure of (A) in Figure 6, the AMF can first execute the fourth condition determination. The fourth condition determination is for determining whether the AMF transmits and receives SM messages to and from the SMF.

[0219] Furthermore, the fourth condition determination may be performed based on whether the AMF has received an SM message. Furthermore, the fourth condition determination may be performed based on whether an SM message is included in the registration request message. For example, if the AMF has received an SM message and / or if the registration request message includes an SM message, the fourth condition determination may be true, and if the AMF has not received an SM message and / or if the registration request message does not include an SM message, the fourth condition determination may be false. Furthermore, the conditions that determine the truth or falsity of the fourth condition determination do not have to be limited to the conditions described above.

[0220] Next, the AMF transmits a registration accept message to the UE via the 5G AN (or gNB) as a response message to the registration request message based on the reception of the registration request message and / or the completion of the transmission and reception of an SM message with the SMF (S608). For example, if the fourth condition determination is false, the AMF may transmit the registration accept message based on the reception of the registration request message from the UE. Also, if the fourth condition determination is true, the AMF may transmit the registration accept message based on the completion of the transmission and reception of an SM message with the SMF. Note that the registration accept message is a NAS message transmitted and received on the N1 interface, but is transmitted and received between the UE and the 5G AN (gNB) included in an RRC message.

[0221] The AMF may include any one or more of the fourth to seventh identification information in the registration acceptance message and send it.

[0222] Furthermore, when multiple pieces of identification information are transmitted and received, two or more of these 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 for use of the function may be transmitted and received as the same identification information, or may be transmitted and received as different identification information.

[0223] Furthermore, whether or not to include any one or more of the fourth to seventh identification information in the registration acceptance message may be selected or determined based on each identification information received by the AMF from the UE or each device, 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.

[0224] Furthermore, the AMF can include and transmit an SM message in a registration accept message, or can transmit an SM message together with the registration accept message. However, this transmission method may be performed when the SM message is included in the registration request message and the fourth condition determination is true. Also, this transmission method may be performed when the SM message is included together with the registration request message and the fourth condition determination is true. By performing such a transmission method, the AMF can indicate that the procedure for SM has been accepted in the registration procedure. Here, the SM message may be a PDU session establishment request message or a PDU session establishment accept message.

[0225] The AMF may also indicate that the UE's request has been accepted by sending a registration acceptance message based on the received identification information, and / or subscription 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.

[0226] Furthermore, the AMF may include information indicating that some of the UE's requests have been rejected in the registration acceptance message and send it, or may indicate the reason why some of the UE's requests have been rejected by sending the information indicating that some of the UE's requests have been rejected. Furthermore, the UE may recognize the reason why some of the UE's requests have been rejected by receiving the information indicating that some of the UE's requests have been rejected. Note that the reason for the rejection may be information indicating that the content indicated by the identification information received by the AMF is not permitted.

[0227] The UE receives a registration acceptance message from the AMF via the 5G AN (gNB) (S608). By receiving the registration acceptance message, the UE can recognize that the UE's request via the registration request message has been accepted and the contents of various identification information included in the registration acceptance message.

[0228] Here, a UE that receives a registration acceptance message from the AMF may recognize and store the information indicated by any one or more of the received fourth to seventh identification information.

[0229] Furthermore, the UE may send a registration completion message to the AMF via the 5G AN (gNB) as a response message to the registration acceptance message (S610). Here, the registration completion message is an NAS message transmitted and received on the N1 interface, but is included in an RRC message and transmitted and received between the UE and the 5G AN (gNB).

[0230] The AMF receives a registration completion message via the 5G AN (gNB) (S610). In addition, each device completes the procedure of (A) in FIG. 6 based on the transmission and reception of the registration acceptance message and / or the registration completion message.

[0231] Next, a case where the first condition determination is false will be described. In the procedure of (B) of Fig. 6, the AMF transmits a registration reject message to the UE via the 5G AN (gNB) as a response message to the registration request message (S612). Here, the registration reject message is an NAS message transmitted and received on the N1 interface, but is transmitted and received between the UE and the 5G AN (gNB) as an RRC message.

[0232] Furthermore, the AMF may indicate that the UE's request via the registration request message has been rejected by sending a registration rejection message. Furthermore, the AMF may include information indicating the reason for the rejection in the registration rejection message and send it, or may indicate the reason for the rejection by sending the reason for the rejection. Furthermore, the UE may recognize the reason for the rejection of the UE's request by receiving information indicating the reason for the rejection of the UE's request. Note that the reason for the rejection may be information indicating that the content indicated by the identification information received by the AMF is not permitted.

[0233] The UE receives a registration rejection message from the AMF via the 5G AN (gNB) (S612). By receiving the registration rejection message, the UE can recognize that the UE's request via the registration request message has been rejected and the contents of the various identification information included in the registration rejection message. Furthermore, if the UE does not receive a registration rejection message even after a predetermined period has elapsed since sending the registration request message, the UE may recognize that the UE's request has been rejected. Each device completes the procedure (B) in this procedure based on the transmission and reception of the registration rejection message.

[0234] The procedure in FIG. 6(B) may be started when the procedure in FIG. 6(A) is stopped.

[0235] Each device completes the registration procedure based on the completion of the procedure of (A) or (B) in Figure 6. Note that each device may transition to a state in which the UE is registered in the network (RM-REGISTERED state) based on the completion of the procedure of (A) in Figure 6, or may maintain a state in which the UE is not registered in the network (RM-DEREGISTERED state) or transition to a state in which the UE is not registered in the network based on the completion of the procedure of (B) in Figure 6. Furthermore, the transition of each device to each state may be based on the completion of the registration procedure or the establishment of a PDU session.

[0236] The UE may also complete the registration procedure based on receiving a registration accept message or a registration reject message.

[0237] 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 the core network_B or another cell.

[0238] 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.

[0239] The UE may recognize the content of the above identification information by receiving a registration acceptance message or a registration rejection message.

[0240] The behavior to be performed when each piece of identification information is received may be performed based on the received identification information.

[0241] [4.2. Session Management Procedure] The session management (SM) procedure will be described with reference to Figure 7. The gNB described in Figure 7 may be a gNB mounted on a satellite, a gNB mounted on a satellite supporting a store-and-forward function, a satellite, or a satellite supporting a store-and-forward function. In this specification, unless otherwise specified, the gNB described in the description of the session management procedure may be a gNB mounted on a satellite supporting a store-and-forward function, or a satellite supporting a store-and-forward function.

[0242] Here, the session management procedure may include a PDU Session Establishment procedure, a PDU Session Modification procedure, a PDU Session Release procedure, or a PDU session authentication and authorization procedure.

[0243] These session management procedures may include procedures initiated by a UE request (UE-requested) and procedures initiated by a network request (NW-requested). In this specification, a procedure initiated by a network request is also referred to as a network initiated (NW-init) procedure, and a procedure initiated by a UE request is also referred to as a UE initiated (UE-init) procedure.

[0244] More specifically, for example, the PDU session establishment procedure may include only a UE-requested procedure. Also, for example, the PDU session modification procedure or the PDU session release procedure may include both a UE-requested procedure and a NW-requested procedure. Also, for example, the PDU session authentication and authorization procedure may include only a NW-requested procedure.

[0245] Furthermore, the UE-requested PDU session modification procedure or the UE-requested PDU session release procedure may be initiated by the UE sending a request message, and the respective procedure may then be executed or completed by executing the network-requested PDU session modification procedure or the network-requested PDU session release procedure, or by sending a response message (e.g., a rejection message) from the NW to the UE, as will be described in more detail below.

[0246] Next, each of the above-mentioned session management procedures will be explained.

[0247] The process (A) in the session management procedure shown in Fig. 7 may be a process that is executed only in the UE-requested PDU session modification procedure and the UE-requested PDU session release procedure. In other words, in the PDU session establishment procedure or the PDU session authentication and authorization procedure, the process (A) in the session management procedure shown in Fig. 7 does not need to be executed, and only the transmission of a session management request message from the UE to the SMF (S700) and the transmission of a TiSeoul response message to the session management request message from the SMF to the UE (S706) may be executed.

[0248] Furthermore, in the network-requested PDU session modification procedure and the network-requested PDU session release procedure, only the process (A) in the session management procedure (hereinafter also simply referred to as the process (A)) may be executed. In other words, in the network-requested PDU session modification procedure and the network-requested PDU session release procedure, only the transmission of a command message from the SMF to the UE (S702) and the transmission of a response message to the command message from the UE to the SMF (S704) may be executed. In other words, the process (A) in the session management procedure may be the network-requested PDU session modification procedure or the network-requested PDU session release procedure.

[0249] Next, each step of the session management procedure will be explained.

[0250] First, the UE sends a session management request message to the core network (S700). More specifically, the UE sends the session management request message (also referred to as an SM request message) to the SMF via the gNB ((R)AN) and the AMF. In addition, the UE may send the session management request message to the network to start a UE-requested session management procedure.

[0251] Here, the session management request message may be, for example, a PDU session establishment request message in a UE-requested PDU session establishment procedure, a PDU session modification request message in a UE-requested PDU session modification procedure, a PDU session release request message in a UE-requested PDU session release procedure, or a 5GSM status message in a 5GSM status procedure. Note that, for example, in a network-requested PDU session modification procedure, a network-requested PDU session release procedure, or a PDU session authentication and authorization procedure, transmission of a session management request message from the UE to the SMF may not be performed.

[0252] Furthermore, the UE that has sent the session management request message to the SMF may start a timer for session management. More specifically, the session management timer (SM timer) executed by the UE may use timer T3580 in a UE-requested PDU session establishment procedure, timer T3581 in a UE-requested PDU session modification procedure, or timer T3582 in a PDU session release procedure, for example.

[0253] Next, the SMF that receives the session management request message from the UE may perform the process of (A) or send a response message to the session management request to the UE (S706).

[0254] Next, the process (A) during the session management procedure will be described. In the process (A), the SMF sends a command message to the UE via the AMF and the gNB. More specifically, the command message may be, for example, a PDU session modification command message, a PDU session release command message, or a PDU session authentication command message in the PDU session authentication and authorization procedure.

[0255] Furthermore, the SMF that sent the session management request message to the UE may execute a timer for session management. More specifically, the session management timer (SM timer) executed by the SMF may use timer T3591 in a network-requested PDU session modification procedure, timer T3592 in a network-requested PDU session release procedure, or timer T3590 in a PDU session authentication and authorization procedure.

[0256] Subsequently, the UE that has received the command message from the SMF via the AMF and the gNB (S702) may transmit a response message to the command message to the network (S706). More specifically, the response message to the command message may be, for example, a PDU session modification complete message or a PDU session modification command reject message in a PDU session modification procedure, a PDU session release complete message in a PDU session release procedure, or a PDU session authentication complete message in a PDU session authentication and authorization procedure.

[0257] Here, the network-requested PDU session change procedure and the network-requested PDU session change procedure complete or terminate the session management procedure upon receiving a response message corresponding to the command from the UE, and there is no need to perform the subsequent procedures described in Figure 7.

[0258] Alternatively, when responding to a session management request message received from the UE, or when rejecting each procedure or a response from the UE in each procedure without performing the process of (A), the SMF transmits a response message to the session management request message (also referred to as an SM response message) to the UE (S706). More specifically, for example, in a PDU session establishment procedure, when the SMF receives a PDU session establishment request message from the UE (S700), it may transmit a PDU session establishment accept message or a PDU session establishment reject message to the UE (S706). Note that the PDU session establishment procedure does not need to perform the process of (A).

[0259] Also, for example, in a PDU session modification procedure or a PDU session release procedure, if the SMF rejects a PDU session modification request message or a PDU session release request message (S702) received from the UE, it may send a PDU session modification rejection message or a PDU session release rejection message to the UE (S706).

[0260] If the UE does not receive a command message or a response message to the session management request from the network (i.e., the SMF) before the SM timer, which starts when the UE transmits a session management request message, expires, the UE may retransmit the session management request message. Furthermore, the UE can repeat the transmission of the SM request message and the start and expiration of the SM timer up to five times, and when the SM timer expires for the fifth time, the UE will abort the various SM procedures.

[0261] In addition, if the SMF does not receive a response to the command message from the UE before the SM timer that starts when the SMF sends various command messages expires, the SMF may resend the command message. Furthermore, the SMF can repeat the start and expiration of the command message and SM timer up to five times, and when the SM timer expires for the fifth time, the SMF will abort various SM procedures.

[0262] Here, as a specific example of the session management procedure, a PDU session establishment procedure will be described in more detail. The UE may start the PDU session procedure by sending a PDU session establishment request message to the network as a session management request message (S700). More specifically, the UE may send the PDU session establishment request message to the SMF via the gNB ((R)AN) and the AMF.

[0263] Furthermore, the UE that sent the PDU session establishment request message may start timer T3580 as a session management timer.

[0264] Next, the network transmits a response message to the UE in response to the session management request message received from the UE (S706). More specifically, the SMF may transmit a PDU session establishment accept message or a PDU session establishment reject message to the UE as a response message to the PDU session request message received from the UE. When the UE receives the PDU session establishment accept message or the PDU session establishment reject message transmitted by the SMF via the AMF and the gNB ((R)AN), the UE and / or each device may terminate the PDU session establishment procedure.

[0265] Furthermore, the UE may stop timer T3580 based on receiving a PDU session establishment rejection or acceptance message from the SMF. If the UE does not receive a PDU session establishment rejection or acceptance message before the expiration of timer T3580, the UE may send a PDU session establishment request message to the SMF again. Furthermore, the expiration of timer T3580 and the retransmission of the PDU session establishment request message may be performed four times, and the UE may terminate the PDU session establishment procedure based on the fifth expiration of timer T3580.

[0266] Above, we have explained a specific example of a PDU session establishment procedure as a specific example of a session management procedure, but other SM procedures may also operate in accordance with the explanation in this chapter, and each message sent and received in the procedure of this embodiment may be interpreted as the message name, timer, and timer value of each other SM procedure.

[0267] This chapter has explained the sending and receiving of messages between conventional UEs and network devices that do not use store-and-forward functionality, and the processing of session management timers in session management procedures requested by UEs and networks.

[0268] Details and examples of session management procedures that take into account the use of store-and-forward functionality are provided in Chapter 5.

[0269] [5. Embodiments] Next, each embodiment of this example will be described. Note that each embodiment described in this chapter is based on the definitions of terms and various identification information explained in Chapter 3, and the procedures explained in Chapter 4.

[0270] In addition, each embodiment may be an embodiment that starts in a state where the UE connects to the network via NR satellite access and registration is completed. Furthermore, each embodiment may be in a state where the UE, each device of the network, and the satellite support a store-and-forward function and are capable of communication via the control plane and / or communication via the user plane using the store-and-forward function.

[0271] In other words, each of the present embodiments may be an embodiment that starts when the UE sends a registration request message during an initial registration procedure or a registration update procedure, the registration request message including any one or more of the first to third identification information indicating that the UE supports or requests or prefers the store-and-forward function, and receives a registration accept message from the network including any one or more of the fourth to seventh identification information indicating that the UE supports or uses the store-and-forward function.

[0272] The purpose of each embodiment described in this chapter is to solve the problem of performing conventional processing that does not consider the store-and-forward function in a session management procedure when the UE, satellite, and core network support the store-and-forward function. More specifically, for example, in a situation where the service link is enabled but the feeder link is not enabled, an embodiment is described that provides a solution for preventing the SM procedure performed by the UE and / or each device in the network from being aborted if the UE transmits a message and the SM timer expires five times. Conversely, for example, in a situation where the feeder link is enabled but the service link is not enabled, an embodiment is described that provides a solution for preventing the SM procedure performed by the UE and / or each device in the network from being aborted if the network transmits a message and the SM timer expires five times.

[0273] Furthermore, unless otherwise specified, the embodiments in this example are not limited to being implemented individually and independently as each embodiment described in each section of this chapter, but may be implemented as a combination of one or more embodiments described in each section, or one or more embodiments described in each section may be implemented in any order.

[0274] Each embodiment of the examples will be described below.

[0275] [5.1. First Embodiment] A first embodiment of this embodiment will be described. Hereinafter, in this section, the first embodiment will also be referred to as the present embodiment. As an example of the operation of this embodiment, a UE, a satellite, and each device of the network executes a PDU session establishment procedure after completing a registration procedure.

[0276] Here, this embodiment may be an embodiment in which the UE sends a registration request message during an initial registration procedure or a registration update procedure, the registration request message including any one or more of the first to third identification information indicating that the UE supports or requests or prioritizes the store-and-forward function, and receives a registration acceptance message from the network including any one or more of the fourth to seventh identification information indicating that the UE supports or uses the store-and-forward function.

[0277] More specifically, the UE of this embodiment completes the registration procedure by, for example, sending a registration request message to the network including a first identification information as capability information indicating that the UE supports the store-and-forward function, and receiving a registration acceptance message from the network including a sixth identification information indicating that the UE will use at least the store-and-forward function.

[0278] Subsequently, in the PDU session establishment procedure requested and initiated by the UE, a PDU session establishment request message is sent, and upon sending the PDU session establishment request message, timer T3580 is started as an SM timer, and the timer value of timer T3580 may take into account the store-and-forward function and may be a value used in communication using the store-and-forward function. Furthermore, the UE may set timer T3580 to a timer value taking into account the store-and-forward function based on receiving the sixth identification information, and execute the timer.

[0279] Here, the timer value of the timer T3580 taking into account the store-and-forward function may be a value different from the value of the conventional timer T3580 used in communication not taking into account the store-and-forward function, and may be a value longer than the conventional timer T3580. Here, the value of the timer T3580 taking into account the store-and-forward function may be a seventh identification information included in a registration accept message received by the UE from the network.

[0280] Alternatively, the timer T3580 taking the store-and-forward function into consideration may be a timer different from the conventional timer T3580 not taking the store-and-forward function into consideration, and the timer value set for the timer T3580 taking the store-and-forward function into consideration may be a longer value than the timer value set for the conventional timer T3580. Here, the value of the timer T3580 taking the store-and-forward function into consideration may be a seventh identification information included in the registration accept message received by the UE from the network.

[0281] Furthermore, when the UE has already stored the timer value of the store-and-forward timer T3580 and receives a seventh identity from the network including a new timer value for the store-and-forward timer T3580, the UE may replace the stored timer value with the new timer value, set the new timer value for the timer T3580, or replace the timer value already set for the timer T3580 with the new timer value. Here, the UE may receive a registration accept message from the network including the seventh identity together with the sixth identity. Furthermore, when the timer value of the seventh identity received by the UE is "0", the UE may erase the stored timer value of the store-and-forward timer T3580.

[0282] In addition, the timer value taking into account the store-and-forward function may be set taking into account the time it takes for the feeder link to become active or restored between the UE sending a session management request message and executing the SM timer up to five times with the timer value taking into account the store-and-forward function.

[0283] The above describes an example of a session management procedure that a UE performs after a registration procedure, mainly a PDU session establishment procedure, but the same processing may also be applied to a PDU session modification procedure or PDU session release procedure requested by the UE or the network, or a PDU session authentication and authorization procedure requested by the network.

[0284] [5.2. Second Embodiment] A second embodiment of this embodiment will be described. In this section, the second embodiment will also be referred to as the present embodiment. As an example of the operation of this embodiment, a UE, a satellite, and each device of the network executes a PDU session establishment procedure after completing a registration procedure.

[0285] Here, this embodiment may be an embodiment in which the UE sends a registration request message during an initial registration procedure or a registration update procedure, the registration request message including any one or more of the first to third identification information indicating that the UE supports or requests or prioritizes the store-and-forward function, and receives a registration acceptance message from the network including any one or more of the fourth to seventh identification information indicating that the UE supports or uses the store-and-forward function.

[0286] More specifically, the UE of this embodiment completes the registration procedure by, for example, sending a registration request message to the network including a first identification information as capability information indicating that the UE supports the store-and-forward function, and receiving a registration acceptance message from the network including a sixth identification information indicating that the UE will use at least the store-and-forward function.

[0287] Subsequently, in a PDU session establishment procedure requested and initiated by the UE, even if the transmission of a PDU session establishment request message and the start and expiration of timer T3580 associated with the transmission of the PDU session establishment request message are repeated five or more times, the PDU session establishment procedure is not terminated and may be repeated more than five times until a PDU session establishment acceptance message or a PDU session request message is received from the network as a response message to the session management request message.

[0288] In other words, for example, the UE may transmit another PDU session establishment request message upon the fifth expiration of timer T3580 and start timer T3580 upon the transmission. Furthermore, the UE may not transition to the "PROCEDURE TRANSACTION INACTIVE state" upon the fifth expiration of timer T3580.

[0289] This embodiment takes into account the store-and-forward function and provides processing by the UE and / or each device in the network to complete the SM procedure without aborting it by repeatedly sending session management messages and starting and expiring a timer until the feeder link is enabled or restored.

[0290] The above describes an example of a session management procedure that a UE performs after a registration procedure, mainly a PDU session establishment procedure, but the same processing may also be applied to a PDU session modification procedure or PDU session release procedure requested by the UE or the network, or a PDU session authentication and authorization procedure requested by the network.

[0291] [5.3. Third Embodiment] A third embodiment of this embodiment will be described. In this section, the third embodiment will also be referred to as the present embodiment. As the operation of this embodiment, an example will be described in which each device of the UE, satellite, and network executes a PDU session establishment procedure after completing the registration procedure.

[0292] Here, this embodiment may be an embodiment in which the UE sends a registration request message during an initial registration procedure or a registration update procedure, the registration request message including any one or more of the first to third identification information indicating that the UE supports or requests or prioritizes the store-and-forward function, and receives a registration acceptance message from the network including any one or more of the fourth to seventh identification information indicating that the UE supports or uses the store-and-forward function.

[0293] Furthermore, this embodiment may be an embodiment that further considers network slices that support store-and-forward functionality for each behavior of the UE and / or network described in the first or second embodiment.

[0294] More specifically, the UE of this embodiment completes the registration procedure by, for example, including a first identity as capability information indicating that the UE supports the store-and-forward function and / or a second identity indicating one or more network slices (S-NSSAIs) supporting the store-and-forward function in a registration request message and transmitting the message to the network, and receiving a registration accept message from the network including at least a sixth identity indicating use of the store-and-forward function and / or a fifth identity indicating one or more network slices supporting the store-and-forward function. Here, the fifth identity may be an allowed NSSAI including an S-NSSAI supporting communication using the store-and-forward function.

[0295] Subsequently, when the UE requests and initiates a PDU session establishment procedure for an S-NSSAI that supports the store-and-forward function and is included in the allowed NSSAI, the UE starts timer T3580 upon transmitting the PDU session establishment request message based on the sixth identification information. Here, the timer value of timer T3580 may be a timer value that takes into account the store-and-forward function and is used in communications using the store-and-forward function. Furthermore, the UE may set timer T3580 to a timer value that takes into account the store-and-forward function based on reception of the sixth identification information, and execute the timer. Here, the timer value and the behavior of each device of the related UE and / or network may be the same as the timer value described in the first embodiment, and detailed description thereof will be omitted.

[0296] Or, more specifically, the UE of this embodiment completes the registration procedure by, for example, including a first identity as capability information indicating that the UE supports the store-and-forward function and / or a second identity indicating one or more network slices (S-NSSAIs) supporting the store-and-forward function in a registration request message and transmitting the message to the network, and receiving a registration accept message from the network including at least a sixth identity indicating use of the store-and-forward function and / or a fifth identity indicating one or more network slices supporting the store-and-forward function. Here, the fifth identity may be an allowed NSSAI including an S-NSSAI supporting communication using the store-and-forward function.

[0297] Subsequently, when the UE requests and initiates a PDU session establishment procedure for an S-NSSAI that supports the store-and-forward function and is included in the allowed NSSAI, the UE transmits a PDU session establishment request message and starts timer T3580 associated with the transmission of the PDU session establishment request message. Here, the timer value of timer T3580 initiated by the UE based on the reception of the sixth identification information may be a value used in communications using the store-and-forward function, taking into account the store-and-forward function. Furthermore, here, even if the UE transmits the PDU session establishment request message and starts and expires timer T3580 five or more times, the UE does not abort the PDU session establishment procedure, and may repeat the process more than five times until it receives a PDU session establishment accept message or a PDU session request message as a response message to the session management request message from the network. Here, the behavior of each device of the UE and / or network regarding the retransmission of the SM message more than five times and the SM timer may be the same as the timer values ​​described in the second embodiment, and detailed description thereof will be omitted.

[0298] The above describes an example of a session management procedure that a UE performs after a registration procedure, mainly a PDU session establishment procedure, but the same processing may also be applied to a PDU session modification procedure or PDU session release procedure requested by the UE or the network, or a PDU session authentication and authorization procedure requested by the network.

[0299] [5.4. Fourth embodiment] A fourth embodiment of this example will be described. In this section, the fourth embodiment will also be referred to as this embodiment.

[0300] This embodiment relates to a process of the network in which, if the network recognizes that the UE, the satellite, and each device of the network are capable of communication using the store-and-forward function, the network can start an SM procedure requested by the network even if the UE is in an unavailability period due to discontinuous satellite coverage.

[0301] Furthermore, this embodiment relates to the network behavior in a network-requested SM procedure that is performed when the UE, satellite, and network devices support the store-and-forward function and the feeder link is valid but the service link is not valid.

[0302] Furthermore, this embodiment may be an embodiment in which the UE sends a registration request message during an initial registration procedure or a registration update procedure, the registration request message including any one or more of the first to third identification information indicating that the UE supports or requests or prioritizes the store-and-forward function, and receives a registration acceptance message from the network including any one or more of the fourth to seventh identification information indicating that the UE supports or uses the store-and-forward function.

[0303] More specifically, the SMF of this embodiment may recognize that it is possible to initiate an SM procedure even if the UE is outside the UE coverage area based on discontinuous satellite coverage, for example, by receiving a registration request message including first identification information as capability information indicating that the UE supports the store-and-forward function.

[0304] Subsequently, the network-requested PDU session modification procedure, PDU session release procedure, or PDU session authentication and authorization procedure executed by the SMF may be the same as the respective behaviors and processes described in the first to third embodiments. In other words, the behavior of the SMF in this embodiment may be the same as other behaviors, for example, when the UE is replaced with the SMF. More specifically, the respective behaviors and processes on the SMF side regarding the value of the SM timer, and / or the number of SM message retransmissions and SM timer expirations, and / or the number of retransmissions taking into account a network slice supporting the store-and-forward function, and / or the number of SM message retransmissions and SM timer expirations taking into account a network slice supporting the store-and-forward function, may be the same as those on the UE side.

[0305] [5.5. Fifth embodiment] A fifth embodiment of this example will be described. In this section, the fifth embodiment will also be referred to as this embodiment.

[0306] Here, this embodiment may be an embodiment in which the UE sends a registration request message during an initial registration procedure or a registration update procedure, the registration request message including any one or more of the first to third identification information indicating that the UE supports or requests or prioritizes the store-and-forward function, and receives a registration acceptance message from the network including any one or more of the fourth to seventh identification information indicating that the UE supports or uses the store-and-forward function.

[0307] After completing the registration procedure, the UE of this embodiment may execute a PDU session establishment procedure requested by the UE, as in the first to third embodiments. Here, the UE may abort the PDU session establishment procedure and transition to the "PROCEDURE TRANSACTION INACTIVE state" if the UE transmits a PDU session establishment request message and the associated SM timer T3580 starts and expires five times. Here, if the UE that has transitioned to the "PROCEDURE TRANSACTION INACTIVE state" receives a PDU session establishment accept message from the network, the UE may recognize that the PDU session has been established. In other words, a UE performing communication using the store-and-forward function may retain the context related to the PDU session establishment procedure without deleting it even after transitioning to the "PROCEDURE TRANSACTION INACTIVE state."

[0308] The above describes an example of a session management procedure that a UE performs after a registration procedure, mainly a PDU session establishment procedure, but the same processing may also be applied to a PDU session modification procedure or PDU session release procedure requested by the UE or the network, or a PDU session authentication and authorization procedure requested by the network.

[0309] [6. Modifications] A program running on an apparatus according to one aspect of this embodiment 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 one aspect of this embodiment. 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 another storage device system.

[0310] A program for realizing the functions of an embodiment according to one aspect of this example may be recorded on a computer-readable recording medium. The program may be read 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.

[0311] 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 embodiments may utilize new integrated circuit technologies that replace current integrated circuits.

[0312] It should be noted that this example is not limited to the above-described embodiment. In the embodiment, one example of a device is described, but this example is not limited to this and can be applied to terminal devices or communication devices such as stationary or non-movable electronic devices installed indoors or outdoors, for example, AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0313] Although the embodiment of this example has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design modifications within the scope of this example are also included. Furthermore, various modifications of this example are possible 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 this example. Furthermore, configurations in which elements described in each of the above embodiments are substituted with elements that achieve the same effect are also included.

[0314] One aspect of the present invention can be used, for example, in a communication system, a communication device (e.g., a mobile phone device, a base station device, a wireless LAN device, or a sensor device), an integrated circuit (e.g., a communication chip), or a program.

[0315] 1 Mobile communication system 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 235 UPF_A 239 UPF_C

Claims

1. A UE (User Equipment) comprising a transmission / reception unit and a control unit, wherein the transmission / reception unit transmits capability information indicating that the UE supports a store-and-forward function to a network, and receives first information indicating that the network uses the store-and-forward function from the network; and the control unit, based on the first information, repeats transmission of a PDU (Protocol Data Unit) session establishment request message by the transmission / reception unit, start and expiration of a first timer associated with the transmission of the PDU session establishment request message, even when the number of repetitions reaches 5 or more times, without aborting the PDU session establishment procedure, and repeats until a response message is received from the network.

2. The UE according to claim 1, wherein the transmission / reception unit transmits the PDU session establishment request message at the timing when the first timer expires 5 times, and the control unit starts the first timer at the timing when the PDU session establishment request message is transmitted.

3. A UE (User Equipment) comprising a transmission / reception unit and a control unit, wherein the transmission / reception unit transmits to the network, including in the requested NSSAI (Network Slice Selection Assistance Information), capability information indicating that the UE supports the store-and-forward function and one or more S-NSSAIs (Single Network Slice Selection Assistance Information) that support communication by the store-and-forward function; receives from the network an allowed NSSAI including first information indicating that the network uses the store-and-forward function and one or more S-NSSAIs that support communication by the store-and-forward function; when the UE executes a PDU (Protocol Data Unit) session establishment procedure for an S-NSSAI that supports the store-and-forward function included in the allowed NSSAI, the control unit, based on the first information, repeats the transmission of a PDU session establishment request message by the transmission / reception unit and the start and expiration of a first timer associated with the transmission of the PDU session establishment request message, even when the number of repetitions reaches 5 or more times, without aborting the PDU session establishment procedure, and repeats until a response message is received from the network.

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