UE (user equipment)

Abstract

To provide a method of UE attempting / re-trying procedures and sending / resending messages based on control information, and a method of executing appropriate processing based on the control information by transmitting and receiving appropriate control information between a network and UE, taking into consideration whether storage provided in the satellite for store-and-forward communication can be used in communication between UE and a network via a satellite.SOLUTION: UE receives system information including control information indicating the status of a storage for store-and-forward communication provided in a satellite from a base station device gNB provided in the satellite, and determines, on the basis of the control information, whether to execute or start a mobility management procedure, a session management procedure, or a user data transmission / reception procedure via the satellite.SELECTED DRAWING: Figure 7

Description

[Technical Field]

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

[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). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] 3GPP TS 23.501 V18.5.0 (2024-03); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System architecture for the 5G System (5GS); Stage 2 (Release 18) [Non-patent document 2] 3GPP TS 23.502 V18.5.0 (2024-03); 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Procedures for the 5G System (5GS); Stage 2 (Release 18) [Non-patent document 3] 3GPP TS 24.501 V18.6.0 (2024-03); 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3; (Release 18) [Non-patent document 4] 3GPP TR 23.700-29 V0.5.0 (2024-04); 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) Summary of the Invention [Problem to be solved by the invention]

[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, in various communication procedures when a UE and a core network communicate via a satellite using the store-and-forward function provided by the satellite and the storage provided by the satellite, it is not clear how to send and receive appropriate control messages between the network or satellite and the UE, taking into account whether or not the storage provided by the satellite for store-and-forward can be used, and the behavior and processing of each device, including the UE and the satellite, based on these control messages.

[0007] One aspect of this embodiment has been made in consideration of the above circumstances, and its purpose is to provide a means for the UE to attempt / retry procedures and send / retransmit messages based on the control information, and a method for performing appropriate processing based on the control information, by transmitting and receiving appropriate control information between the network and the UE, the network taking into consideration whether or not the storage provided in the satellite for store-and-forward communication can be used, in communication between the UE and the NW via the satellite, in which the UE, satellite, and network supporting the store-and-forward function send / retry appropriate control information. [Means for solving the problem]

[0008] A UE (User Equipment) of one aspect of this embodiment is a UE having a transceiver unit and a control unit, wherein the transceiver unit receives system information including first control information from a base station device provided in a satellite, the first control information being information indicating the status of storage for store-and-forward communication provided in the satellite, and the control unit determines, based on the first control information, whether to execute or start a mobility management procedure, a session management procedure, or a user data transmission / reception procedure via the satellite.

[0009] Moreover, a UE (User Equipment) of one aspect of this embodiment is a UE having a transceiver unit and a control unit, wherein the transceiver unit transmits a registration request message including second control information to a core network device provided in a first satellite during a first registration procedure, the second control information being capability information indicating that the UE supports store-and-forward communication, and if storage for store-and-forward communication provided in the satellite is not available, the transceiver unit receives a registration rejection message including third and fourth control information from the core network device provided in the satellite, the third control information being a rejection reason value indicating that the storage is not available, and the fourth control information being a back-off timer value corresponding to the third control information for when the UE retries the registration procedure, and the control unit sets the back-off timer to the value indicated by the fourth control information, starts the back-off timer, and starts a second registration procedure after the back-off timer expires.

[0010] Furthermore, one aspect of the UE (User Equipment) of this embodiment is a UE having a transceiver unit and a control unit, wherein the transceiver unit transmits user data to a base station device provided in a first satellite, and when storage for store-and-forward communication provided in the satellite is unavailable, the transceiver unit receives a message including seventh control information from a core network device provided in the satellite via the base station device provided in the satellite, the seventh control information being information indicating that storage for store-and-forward communication provided in the satellite is unavailable, and the control unit stops transmitting the user data based on the seventh control information. [Effects of the Invention]

[0011] According to one aspect of this embodiment, when the UE and the satellite support a store-and-forward function, a method is provided for transmitting and receiving appropriate control information between the satellite and the UE, performing appropriate timer management based on the control information, and / or retransmitting appropriate messages, so that the UE can recognize the status of the storage for store-and-forward communication provided in the satellite before performing or initiating various types of MO (mobile originated) communication between the UE and the satellite, and for performing appropriate processing based on the control information. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating an outline of a mobile communication system (EPS / 5GS). [Figure 2] FIG. 1 is a diagram illustrating the detailed configuration of a mobile communication system (EPS / 5GS). [Figure 3] FIG. 1 is a diagram illustrating the device configuration of a UE. [Figure 4] A diagram explaining the configuration of an access network device (gNB) in 5GS. [Figure 5] A diagram explaining the configuration of core network devices (AMF / SMF / UPF) in 5GS. [Figure 6] FIG. 10 is a diagram illustrating a registration procedure. [Figure 7] FIG. 1 is a diagram illustrating a session management procedure. DETAILED DESCRIPTION OF THE INVENTION

[0013] 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.

[0014] [1. System Overview] First, FIG. 1 is a diagram for explaining an outline of a mobile communication system 1 used in each embodiment, and FIG. 2 is a diagram for explaining a detailed configuration of the mobile communication system 1. As shown in FIG.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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).

[0024] 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.

[0025] 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.

[0026] 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).

[0027] 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.

[0028] 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.

[0029] 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).

[0030] 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.

[0031] 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.

[0032] 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.

[0033] Here, IP communication refers to data communication using IP, and data is transmitted and received using IP packets. An IP packet consists of an IP header and a payload. The payload may include data transmitted and received by devices and functions included in EPS or devices and functions included in 5GS. Non-IP communication refers to data communication that does not use IP, and data is transmitted and received in a format different from the IP packet structure. For example, non-IP communication may be data communication achieved by transmitting and receiving application data without an IP header, or it may be user data transmitted and received by a UE with a different header, such as a MAC header or an Ethernet (registered trademark) frame header, added.

[0034] 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).

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] [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.

[0042] Note that each memory unit (memory unit_A340, memory unit_A440, memory unit_B540, memory unit_A640, memory unit_B740) in each device / function mentioned below is configured with, for example, a semiconductor memory, a solid state drive (SSD), a hard disk drive (HDD), etc. Furthermore, each memory unit can store not only information that was originally set at the time of shipment, but also various information transmitted and received between devices / functions other than the device / function itself (e.g., UE, and / or access network device, and / or core network device, and / or PDN, and / or DN). Furthermore, each memory unit can store identification information, control information, flags, parameters, etc. included in control messages transmitted and received in various communication procedures described below. Furthermore, each memory unit may store this information for each UE. Furthermore, when interworking between 5GS and EPS is performed, each memory unit can store control messages and user data transmitted and received between 5GS and / or devices / functions included in EPS. At this time, not only those transmitted and received via the N26 interface but also those transmitted and received without going through the N26 interface can be stored.

[0043] [2.1. UE Device Configuration] First, an example of the device configuration of UE (User Equipment) will be explained using Figure 3. The UE is composed of a control unit _A300, an antenna 310, a transceiver unit _A320, and a memory unit _A340. The control unit _A300, the transceiver unit _A320, and the memory unit _A340 are connected via a bus. The transceiver unit _A320 is connected to the antenna 310.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] The memory unit _A340 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the UE.

[0048] [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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] The memory unit _B540 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the gNB.

[0054] [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.

[0055] The control unit _B700 is a functional unit that controls the operation and functions of the entire AMF.The control unit _B700 realizes various processing in the AMF by reading and executing various programs stored in the memory unit _B740 as necessary.

[0056] 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.

[0057] 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.

[0058] The memory unit _B740 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the AMF.

[0059] The AMF has functions such as exchanging control messages with the RAN using the N2 interface, exchanging NAS messages with the UE using the N1 interface, encrypting and protecting the integrity of NAS messages, registration management (RM) functions, connection management (CM) functions, reachability management functions, mobility management functions for UEs, etc., transferring SM (Session Management) messages between the UE and the SMF, access authentication (Access Authorization) functions, security anchor functionality (SEA), security context management (SCM), supporting the N2 interface for the N3IWF (Non-3GPP Interworking Function), supporting the transmission and reception of NAS signals with the UE via the N3IWF, and authenticating the UE connected via the N3IWF.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] [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.

[0069] The control unit _B700 is a functional unit that controls the operation and functions of the entire SMF.The control unit _B700 realizes various processing in the SMF by reading and executing various programs stored in the memory unit _B740 as necessary.

[0070] 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.

[0071] 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.

[0072] The memory unit _B740 is a functional unit for storing programs, user data, control information, etc. required for each operation of the SMF.

[0073] 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.

[0074] [2.5. UPF device configuration] Next, an example of the device configuration of the UPF will be explained using Figure 5. The UPF is composed of a control unit _B700, a network connection unit _B720, and a memory unit _B740. The control unit _B700, the network connection unit _B720, and the memory unit _B740 are connected via a bus. The UPF may be a node that handles the control plane.

[0075] The control unit _B700 is a functional unit that controls the operation and functions of the entire UPF.The control unit _B700 realizes various processing in the UPF by reading and executing various programs stored in the memory unit _B740 as necessary.

[0076] 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.

[0077] 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.

[0078] The memory unit _B740 is a functional unit for storing programs, user data, control information, etc. required for each operation of the UPF.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 2.6. Description of Other Devices and / or Functions Next, other devices and / or functions will be described.

[0085] The PCF has a function to provide policy rules.

[0086] The UDM also has functions such as authentication credential processing, user identification processing, access authentication, registration / mobility management, and subscription management.

[0087] 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.

[0088] 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.

[0089] [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.

[0090] [3.1. Explanation of terms used in each embodiment] Next, highly specialized terms used in each embodiment will be explained.

[0091] 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, 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] Non-5GS services may be services other than 5GS services, and may include EPS services and / or non-EPS services.

[0096] 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.

[0097] 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.

[0098] The DNN (Data Network Name) may be identification information for identifying a core network and / or an external network such as a DN. Furthermore, the DNN can also be used as information for selecting a gateway such as a PGW / UPF that connects the core network B190. Furthermore, the DNN may be equivalent to an APN (Access Point Name).

[0099] 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.

[0100] A PLMN (Public Land Mobile Network) is a communication network that provides mobile radio communication services. A PLMN is a network managed by an operator, which is a communications carrier, and the operator can be identified by a PLMN ID. A PLMN that matches the MCC (Mobile Country Code) and MNC (Mobile Network Code) of a UE's IMSI (International Mobile Subscriber Identity) may be a Home PLMN (HPLMN). Furthermore, a UE may store an Equivalent HPLMN list (also referred to as equivalent HPLMN) in its USIM to identify one or more Equivalent HPLMNs (EPLMNs). A PLMN that is different from the HPLMN and / or EPLMN may be a Visited PLMN (VPLMN). A PLMN to which a UE has successfully registered may be a Registered PLMN (RPLMN).

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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).

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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).

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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).

[0136] 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.

[0137] The information may indicate the type of unavailability period, whether the unavailability period is due to discontinuous NR satellite access coverage, and / or whether the unavailability period is not due to discontinuous NR satellite access coverage. In other words, for example, the type of unavailability period may indicate that the unavailability period is due to discontinuous NR satellite access coverage. Note that the type of unavailability period may also be referred to as the unavailability type or type of unavailability.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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).

[0143] 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."

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] Also, if the UE has stored a discontinuous coverage maximum NAS signal latency due to discontinuous coverage, when it goes out of coverage (i.e., out of range) of NR satellite access and then returns to coverage (i.e., in range), the UE sets 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 starts this timer. While the discontinuous coverage maximum NAS signal latency timer is running, the UE must not initiate NAS signals on that satellite NG-RAN RAT type and PLMN.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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:

[0163] 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.

[0164] 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.

[0165] 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 predetermined geographic area for a limited period of time. In this specification, a serving satellite may also be simply referred to as a satellite.

[0166] Here, the serving satellite or satellite in this specification may be configured to include a base station device and / or a 4G or 5G core network device. In other words, for example, the serving satellite or satellite in this embodiment may be equipped with a base station device and / or a 4G or 5G core network device, and / or one or more 4G or 5G core network devices, or may have the functions thereof. In other words, for example, the base station device included in the satellite in this specification may be, for example, an eNB and / or a gNB. Furthermore, for example, the core network device included in the satellite in this specification may include one or more devices or functions of an MME, an SGW, a PGW-U, a PGW-C, a PCRF, an HSS, an AMF, an UPF, an SMF, an PCF, and / or a UDM.

[0167] More specifically, for example, a satellite in this specification may be configured to include an eNB and / or a gNB. Or, for example, a satellite in this specification may be configured to include an AMF and / or an MME in addition to an eNB and / or a gNB. Or, for example, a satellite in this specification may be configured to include one or more of an eNB and / or a gNB, an AMF and / or an MME, a UPF, and / or a PGW (PGW-U and / or PGW-C) and / or an SFW.

[0168] Also, for example, when a feeder link is unavailable, a satellite may perform all or part of mobility management procedures through a gNB and AMF onboard the satellite. Or, for example, when a feeder link is unavailable, a satellite may perform all or part of session management procedures through a gNB, AMF, and SMG onboard the satellite. 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 an Inter-Satellite Link (ISL). For uplink (UL; communication from a UE to a satellite), "store" refers to onboard storage of UL information from the UE, and "forward" refers to forwarding the stored UL information to the terrestrial network. For downlink (DL; communication from a satellite to a UE), "store" refers to onboard storage of DL information from the terrestrial network, and "forward" refers to forwarding the stored DL information to the UE.

[0169] In this specification, the communication service provided by store-and-forward satellite operation may also be referred to as the store-and-forward function, or store-and-forward, or S&F function, or communication in S&F mode, or S&F. In this specification, communication using the store-and-forward function may also be referred to as store-and-forward communication, or S&F communication. Furthermore, UEs, satellites, and networks that utilize the store-and-forward function or perform store-and-forward communication may support the store-and-forward function and store-and-forward communication. In this specification, support for the store-and-forward function and support for store-and-forward communication may mean the same thing.

[0170] Furthermore, the satellite may be equipped with storage for performing store-and-forward communication. Here, the storage equipped in the satellite for performing store-and-forward communication may be, for example, a storage area or storage device for temporarily storing information received from the UE via a service link that serves as a path for UP or CP communication between the UE and the satellite and to be transmitted to the ground when a feeder link that serves as a path for UP or CP communication between the satellite and a terrestrial base station or core network is unavailable. Here, the CP or UP communication information from the UE that is temporarily stored in the satellite storage may be transferred or transmitted from the satellite storage to a terrestrial base station device or core network when the feeder link becomes available, and the information in the storage after transmission may be deleted based on a request from the terrestrial core network or implementation of a device or function on the satellite.

[0171] Here, to perform store-and-forward communication, the storage provided in the satellite may include the above-mentioned base station device or core network device provided in the satellite, or a function thereof. More specifically, for example, one or more devices or functions among the eNB and / or gNB, AMF and / or MME, UPF, and / or PGW (PGW-U and / or PGW-C) and / or SFW provided in the satellite may include storage for performing store-and-forward communication. In this specification, storage installed in a satellite for store-and-forward communication is also simply referred to as storage.

[0172] The storage onboard or provided by the satellite may be provided by one or more of the satellite, and / or the base station device provided by the satellite, and / or the core network device provided by the satellite. Here, if the satellite is provided with storage for store-and-forward communication, it may be accessible from the base station device and / or the core network device, which are each device onboard the satellite, and may be in a readable and writable state.

[0173] Furthermore, unless otherwise specified in this specification, supporting store-and-forward communication may mean supporting communication between a UE and a base station device and / or core network device provided on a satellite based on a store-and-forward function or a store-and-forward function using storage provided on the satellite.

[0174] Furthermore, the satellite in this specification may refer to a satellite, and / or a base station device provided by the satellite, and / or a core network device provided by the satellite. In other words, in this specification, a satellite, and / or a base station device provided by the satellite, and / or a core network device provided by the satellite will also be simply referred to as a satellite.

[0175] 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.

[0176] [3.2. Description of Identification Information in Each Embodiment] Next, the identification information used in each procedure of each embodiment will be described. Note that each piece of identification information may be control information, and is also referred to as control information in this specification.

[0177] The first identification information in this embodiment may be information indicating the status of a storage device provided in the satellite for storing control information or user data transmitted and received in store-and-forward communication between the UE and the satellite. Furthermore, the first identification information may be information included in broadcast information or system information. Here, the broadcast information may be a Master Information Block (MIB) and / or a System Information Block (SIB). Furthermore, the first identification information may be information transmitted by the satellite or a base station device provided in the satellite and received by the UE.

[0178] More specifically, for example, the first identification information may be identification information indicating that the storage capacity for store-and-forward communication provided by the satellite is available, and / or the storage capacity for store-and-forward communication provided by the satellite is full, and / or the storage for store-and-forward communication provided by the satellite is usable, and / or the storage for store-and-forward communication provided by the satellite is unavailable, and / or the satellite does not have valid storage for store-and-forward communication that can be used by the UE, and / or the satellite has valid storage for store-and-forward communication that can be used by the UE, and / or the UE attempting communication is not authorized or has no priority to use the storage for store-and-forward communication provided by the satellite, and / or the UE attempting communication is authorized or has priority to use the storage for store-and-forward communication provided by the satellite, and / or the contents of the storage for store-and-forward communication provided by the satellite have been erased.

[0179] Furthermore, here, the first identification information, when it indicates, for example, that there is free space in the storage capacity for store-and-forward communication provided by the satellite, and / or that the storage for store-and-forward communication provided by the satellite is usable, and / or that the satellite has valid storage for store-and-forward communication that can be used by the UE, and / or that the UE attempting communication has the authority or priority to use the storage for store-and-forward communication provided by the satellite, and / or that the contents of the storage for store-and-forward communication provided by the satellite have been erased, is also referred to as first identification information indicating that the storage for store-and-forward communication provided by the satellite is usable, or simply that the storage provided by the satellite is usable.

[0180] Alternatively, here, the first identification information in a case where the first identification information indicates, for example, that the storage capacity for store-and-forward communication provided by the satellite is full, and / or that the storage for store-and-forward communication provided by the satellite is unusable, and / or that the satellite does not have valid storage for store-and-forward communication that the UE can use, and / or that the UE attempting communication does not have the authority or priority to use the storage for store-and-forward communication provided by the satellite, and / or that the contents of the storage for store-and-forward communication provided by the satellite have been erased, is also referred to as first identification information indicating that the storage for store-and-forward communication provided by the satellite is unusable, or simply that the storage provided by the satellite is unusable.

[0181] Here, the UE of this embodiment may store and / or interpret and / or judge / determine the first identification information received from the satellite or a base station device (e.g., an eNB or a gNB) provided by the satellite, and based on the first identification information, may determine whether communication is possible using storage provided by the satellite for performing store-and-forward communication.

[0182] More specifically, for example, when a UE in this embodiment receives first identification information indicating that the storage provided by the satellite is available for use from the satellite or a base station device (e.g., an eNB or a gNB) provided by the satellite, the UE recognizes that it is possible to use the storage for store-and-forward communication provided by the satellite, and may initiate, execute, or continue a mobility management procedure, and / or a session management procedure, and / or transmission and reception of user data.

[0183] Or, for example, when a UE in this embodiment receives first identification information from a satellite or a base station device (e.g., an eNB or gNB) provided by the satellite indicating that the storage provided by the satellite is unavailable, the UE may recognize that it is not possible to use the storage for store-and-forward communication provided by the satellite, and may not perform or cancel mobility management procedures, and / or session management procedures, and / or transmission and reception of user data.

[0184] The UE may receive first identification information from a base station device or a base station device onboard a satellite to recognize that the satellite supports a store-and-forward function or store-and-forward communication, and / or may receive first identification information from a base station device or a base station device onboard a satellite to recognize that the satellite supports a store-and-forward function or store-and-forward communication and further has storage for store-and-forward communication.

[0185] In addition, when the UE executes a mobility management procedure, a session management procedure, or a procedure for transmitting and receiving user data, the UE may determine whether or not to execute each procedure based on the contents of the first identification information most recently received, and may execute or not execute each procedure based on that determination.

[0186] 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.

[0187] In this embodiment, the second identification information is the capability information of the UE. The second 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 second identification information indicates that the UE supports communication using the store-and-forward function.

[0188] Here, a UE that supports store-and-forward communication may be capable of communication using the store-and-forward storage provided by the satellite for various procedures using the store-and-forward function or for sending and receiving user data.

[0189] The second identification information may be information included as part of a 5GMM capability, a 5GMM capability Information Element (IE), or a 5GMM capability. Alternatively, the second identification information may be information included as part of a 5GSM capability, a 5GSM capability Information Element (IE), or a 5GSM capability.

[0190] Here, when the UE indicates the second 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.

[0191] Furthermore, when the UE transmits a message including the second identification information to the satellite, and / or a base station device provided in the satellite, and / or a core network device provided in the satellite, the UE may indicate to the satellite, and / or a base station device provided in the satellite, and / or a core network device that the UE requests or prefers store-and-forward communication using the storage provided in the satellite. Also, the satellite receiving the message including the second identification information from the UE may recognize, based on the second identification information, that the UE requests or prefers store-and-forward communication using the storage provided in the satellite. Here, the message including the second identification information may be a request message in a mobility management procedure and / or a request message in a session management procedure.

[0192] 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.

[0193] The twelfth identification information in this embodiment is information indicating support of a network (NW) capability or function. The twelfth identification information may be information indicating that the network or each device in the network supports or does not support the store-and-forward function or store-and-forward communication. Unless otherwise specified in the specification, the twelfth identification information indicates that the UE supports communication using the store-and-forward function.

[0194] In addition, the network may be a core network device mounted on a satellite, and the twelfth identification information may indicate the capability or function supported by the core network device mounted on the satellite. In other words, the twelfth identification information may be information indicating the capability or function supported by the satellite or the core network device mounted on the satellite.

[0195] Furthermore, the 12th identification information may be information included as part of 5GS network feature support, a 5GS network feature support IE, or 5GS network feature support. Alternatively, the 12th 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.

[0196] Here, when the NW indicates the 12th identification information to the network, the UE may recognize that the satellite or the core network device mounted on the satellite supports the store-and-forward function or store-and-forward communication. Furthermore, the UE receiving the 12th identification information from the satellite or the core network device mounted on the satellite may recognize that communication using the store-and-forward function is possible. Furthermore, the UE may recognize that the satellite or the core network device mounted on the satellite has storage for store-and-forward communication. Furthermore, the UE may perform communication taking into account the use of the store-and-forward function by the satellite or the core network device mounted on the satellite, or transition to or activate a mode in which communication using the store-and-forward function is performed.

[0197] Further details of the behavior of the UE and NW based on the 12th identification information are also provided in Chapter 4 and / or Chapter 5.

[0198] Further details of the behavior of the UE and NW based on the 12th identification information are also provided in Chapter 4 and / or Chapter 5.

[0199] In this embodiment, the third identifier is a refusal reason (5GMM cause or 5GSM cause) value, which indicates that the storage for store-and-forward communication provided by the satellite cannot be used or is not permitted.

[0200] The third identification information may be included in a response message in a mobility management procedure or a response message in a session management procedure and transmitted from the satellite to the UE. Furthermore, if the satellite receives second identification information from the UE indicating that store-and-forward communication is not supported, or if the satellite has not received second identification information from the UE, the satellite may not include the third identification information in the message. In other words, if the UE does not support store-and-forward communication, the satellite may not include the third identification information in the message.

[0201] A UE that receives the third identification information from the satellite may recognize that the satellite to which the UE is attempting to connect does not allow or is temporarily or permanently unavailable storage for store-and-forward.

[0202] During an MM procedure or an SM procedure initiated by the UE, the satellite may decide whether to include the third identification information in the MM response message or the SM response message based on a decision made by the satellite or a core network device equipped in the satellite.

[0203] Further details of the behavior of the UE, and / or satellite, and / or NW based on the third identification information are also described in Chapter 4 and / or Chapter 5.

[0204] The fourth identification information in this embodiment may be a back-off timer or a value of the back-off timer. More specifically, the fourth identification information is information that is included in a rejection message and transmitted when a procedure attempted by the UE via a satellite is rejected by the satellite, a core network device on the satellite, or a network. When the timer with the timer value indicated by the fourth identification information expires, the UE may retry the rejected procedure.

[0205] Here, a UE that receives a message including the fourth identification information may recognize that the fourth identification information is a backoff timer value from the format of an information element (IE) included in the message received from a base station device equipped on the satellite.

[0206] More specifically, for example, the fourth identification information may be the value of a back-off timer included in a registration rejection message transmitted and received when a UE is rejected in a registration procedure via a satellite. A UE that receives the fourth identification information may set a back-off timer value indicated by the fourth identification information in a timer within the UE and start the back-off timer. When the back-off timer based on the fourth identification information expires, the UE may start or execute a new registration procedure.

[0207] The fourth identification information may be included in a message together with the fifth identification information and transmitted to the UE. Furthermore, the value of the MM or SM back-off timer indicated by the fourth identification information may be a value longer than usual, and may be expressed in the same format as the unavailable period duration.

[0208] In addition, the back-off timer value indicated by the fourth identification information may be included in a response message or a rejection message of a UE-initiated MM procedure or a UE-initiated SM procedure attempted by the UE via a satellite.

[0209] Further details of the behavior of the UE, and / or satellite, and / or NW based on the fourth identification information are also described in Chapter 4 and / or Chapter 5.

[0210] In this embodiment, the fifth identification information may be information indicating that the satellite requests the UE to change its connection to a satellite different from the satellite with which the UE is currently performing the procedure, and may further include information indicating the satellite to be changed.

[0211] More specifically, the fifth identification information may be, for example, identification information that a UE performing an MM procedure or an SM procedure via satellite #1 receives in a rejection message for each procedure from the satellite or the network.

[0212] Furthermore, if the UE receives the fifth identification information including information indicating another satellite, the UE may switch to the satellite indicated by the fifth identification information to start or perform communication. Alternatively, if the fifth identification information does not include information indicating another satellite, the UE may (re)select an appropriate satellite based on UE implementation, switch to the selected satellite, and start or perform communication.

[0213] Here, the fifth identification information may be included in an MM message in a UE-initiated MM procedure or an SM message in a UE-initiated SM procedure and transmitted to the UE. The MM message or SM message including the fifth identification information may be a rejection message. The fifth identification information may be included in a message together with the third identification information and transmitted from the satellite to the UE.

[0214] Furthermore, the content indicated by the fifth identification information may be the same as the content indicated by the eighth identification information.

[0215] Further details of the behavior of the UE, and / or satellite, and / or NW based on the fifth identification information are also described in Chapter 4 and / or Chapter 5.

[0216] The sixth identification information in this embodiment may be information indicating that the UE is requested to resume or perform user data transmission after a period of unavailability due to discontinuous satellite access, i.e., the sixth identification information indicates that the satellite or the core network device mounted on the satellite requests the UE to resume user data transmission after the UE returns from outside the coverage area of ​​the satellite access provided by the satellite to within the coverage area.

[0217] Here, the sixth identification information may be included in a response message in the UE initiated MM procedure or the UE initiated SM procedure and transmitted. Also, the unavailable period may be a period from when the UE returns from outside the coverage area of ​​the satellite access provided by the satellite to when the UE returns to the coverage area.

[0218] The content indicated by the sixth identification information may be the same as the content indicated by the ninth identification information.

[0219] Further details of the behavior of the UE, and / or satellite, and / or NW based on the sixth identification information are also described in Chapter 4 and / or Chapter 5.

[0220] The seventh identification information in this embodiment may be information indicating that the storage for store-and-forward communication provided by the satellite cannot be used or is not permitted to be used, and may be the same as the first identification information indicating that the storage provided by the satellite is not available.

[0221] Here, the seventh identification information may be transmitted by being included in a response message in the NW-initiated MM procedure or the NW-initiated SM procedure.

[0222] Further details of the behavior of the UE, and / or satellite, and / or NW based on the seventh identification information are also described in Chapter 4 and / or Chapter 5.

[0223] The eighth identification information in this embodiment may be information indicating that the satellite requests the UE to change connection to a satellite different from the satellite on which the UE is performing the procedure and perform the procedure.

[0224] Furthermore, the content indicated by the eighth identification information may be the same as the content indicated by the fifth identification information.

[0225] Here, the eighth identification information may be transmitted by being included in a response message in the NW-initiated MM procedure or the NW-initiated SM procedure.

[0226] Further details of the behavior of the UE and NW based on the eighth identification information are also described in Chapter 4 and / or Chapter 5.

[0227] The ninth identification information in this embodiment may be information indicating that the UE is requested to resume or perform user data transmission after a period of unavailability due to discontinuous satellite access, for example, information indicating that the satellite or the core network device mounted on the satellite requests the UE to resume user data transmission after the UE returns from outside the coverage area of ​​the satellite access provided by the satellite to within the coverage area.

[0228] Here, the ninth identification information may be transmitted in a message for starting a network-initiated MM procedure or a network-initiated SM procedure. In addition, the unavailable period may be a period during which the UE returns from outside the coverage area of ​​the satellite access provided by the satellite to the coverage area.

[0229] The content indicated by the ninth identification information may be the same as that of the sixth identification information.

[0230] Further details of the behavior of the UE, and / or satellite, and / or NW based on the ninth identification information are also provided in Chapter 4 and / or Chapter 5.

[0231] The tenth identification information in this embodiment is information indicating that store-and-forward communication has become possible. More specifically, the tenth identification information may be information indicating that store-and-forward communication has become possible based on, for example, the status of storage provided in the satellite, permission for store-and-forward communication, etc. In other words, the tenth identification information may be information indicating that store-and-forward communication has become possible for a UE that, during transmission of user data via a satellite, stopped or suspended the transmission / reception due to an unavailable period caused by discontinuous satellite access and / or due to a request from the network.

[0232] The tenth identification information may be transmitted in a request message for initiating a NW-initiated MM procedure or a NW-initiated SM procedure.

[0233] Furthermore, the UE that receives the tenth identification information from the satellite may recognize that store-and-forward communication via the satellite is now possible, and may resume or start transmission of user data that had been interrupted or stopped based on the tenth identification information.

[0234] Further details of the behavior of the UE, and / or satellite, and / or NW based on the tenth identification information are also provided in Chapter 4 and / or Chapter 5.

[0235] The eleventh identification information in this embodiment is information indicating user data or a message that the UE has failed to transmit. More specifically, the eleventh identification information may be information indicating user data or a message that has failed to be transferred between the UE and a satellite, for example, when the UE stops or suspends transmission or reception of user data via a satellite due to an unavailable period caused by discontinuous satellite access and / or a request from the network.

[0236] The eleventh identification information may be transmitted in a request message for initiating a NW-initiated MM procedure or a NW-initiated SM procedure.

[0237] Furthermore, the UE that receives the 11th identification information from the satellite may recognize the user data or message that failed to be transferred between the UE and the satellite, and may further transmit or retransmit the user data or message indicated by the 11th identification information when store-and-forward communication via the satellite becomes possible.

[0238] Furthermore, the UE that receives the tenth and eleventh identification information from the satellite may perform or start transmitting or retransmitting the user data or message indicated by the eleventh identification information.

[0239] Further details of the behavior of the UE, and / or satellite, and / or NW based on the 11th identification information are also provided in Chapter 4 and / or Chapter 5.

[0240] The above-mentioned first to twelfth 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 identification information. Furthermore, a single piece of information combining one or more of the first to twelfth 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.

[0241] Details of the behavior of the UE and the network based on one or a combination of the above identification information 1 to 12 are not limited to those described in this chapter, but are also described in Chapter 4 and / or Chapter 5.

[0242] [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 broadcast information / system information, various procedures for mobility management, and various procedures for session management.

[0243] 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.

[0244] Also, as described in Chapter 3, in each embodiment, some of the devices may be mounted on a satellite.

[0245] [4.1. Broadcast information / system information] The broadcast information may be information included in a message, a signal, and / or a beacon frame transmitted to the UE from an AN and / or an eNB or gNB, which is a base station device constituting the AN. Furthermore, the broadcast information may include a MIB (Master Information Block) and / or a SIB (System Information Block).

[0246] Furthermore, the UE that receives the broadcast information and / or the system information from the base station device may store the received information.

[0247] Here, the base station device (eNB or gNB) in this specification may be a base station device or function mounted on a satellite. Furthermore, a satellite equipped with or equipped with a base station device (eNB or gNB) in this specification may support a store-and-forward function or store-and-forward communication, and may further be equipped with storage for store-and-forward communication. Furthermore, the base station device equipped with or equipped on a satellite in this specification may transmit broadcast information and / or system information including the first identification information.

[0248] Furthermore, the base station device mounted on the satellite may change the content indicated by the first identification information depending on the state of the storage provided on the satellite.

[0249] In addition, a UE that receives broadcast information including first identification information from a base station device installed on a satellite may store and / or interpret and / or judge / determine the received first identification information, and based on the first identification information, determine whether communication is possible using storage provided on the satellite for performing store-and-forward communication.

[0250] More specifically, for example, when a UE in this embodiment receives first identification information indicating that the storage provided by the satellite is available for use from the satellite or a base station device (e.g., an eNB or a gNB) provided by the satellite, the UE recognizes that it is possible to use the storage for store-and-forward communication provided by the satellite, and may initiate, execute, or continue a mobility management procedure, and / or a session management procedure, and / or transmission and reception of user data.

[0251] [4.2. Mobility Management Procedures] The Mobility Management (MM) procedure will now be described.

[0252] Here, the MM procedure may include a registration procedure, a de-registration procedure, a generic UE configuration update procedure, a NAS transport procedure, a service request procedure, a notification procedure, etc.

[0253] These MM procedures may include UE-initiated (or UE-requested) procedures and network-initiated (or NW-requested) procedures. In this specification, a network-initiated procedure is also referred to as a network-initiated (NW-init) procedure, and a UE-initiated procedure is also referred to as a UE-initiated (UE-init) procedure.

[0254] More specifically, for example, the non-registration procedure and the NAS transport procedure may include both UE-initiated and NW-initiated procedures. Also, for example, the registration procedure and the service request procedure may only include UE-initiated procedures. Also, for example, the UE configuration update procedure and the notification procedure may only include NW-initiated procedures.

[0255] Furthermore, the UE may include the second identification information in an initial request message for starting a UE-initiated MM procedure and transmit the message to the network, or the network may receive a message including the second identification information from the UE. Furthermore, upon receiving the second identification information from the UE, the network may recognize that the UE supports store-and-forward communication and, based on this recognition, may include one or more of the third to sixth and twelfth identification information in a response message to the request message received from the UE and transmit the response message to the UE. Conversely, if the network does not receive from the UE second identification information indicating that store-and-forward communication is supported or receives from the UE second identification information indicating that store-and-forward communication is not supported, the network may transmit the response message to the UE without including the third to sixth and twelfth identification information, or may transmit the response message to the UE with one or more of the third to sixth and twelfth identification information.

[0256] Here, in a UE-initiated MM procedure, the first message including the second identification information that the UE sends to the network may be a registration request message in a registration procedure, or a deregistration request (DEREGISTRATION REQUEST) message in a deregistration procedure, or a service request message in a service request procedure, or a UL NAS TRANSPORT message in a NAS transport procedure.

[0257] Furthermore, in a UE-initiated MM procedure, the response message including one or more of the third to sixth and twelfth identification information may be a registration accept message or a registration reject message in a registration procedure, or a deregistration accept message in a deregistration procedure, or a service accept message or a service reject message in a service request procedure, or a DL NAS TRANSPORT message in a NAS transport procedure.

[0258] Furthermore, the NW may include one or more of the third to sixth and twelfth identification information in an initial message initiating a NW-initiated MM procedure and transmit the same to the UE, or the UE may receive a message from the NW including one or more of the third to sixth and twelfth identification information. Furthermore, a UE that supports store-and-forward communication and receives one or more of the third to sixth and twelfth identification information from the NW may recognize that the NW supports store-and-forward communication and may store each identification information.

[0259] Here, in a NW-initiated MM procedure, the first message that the NW sends to the UE, which includes one or more of the seventh to eleventh identification information, may be a non-registration request message in a non-registration procedure, or a configuration update command message in a UE configuration update procedure, or a DL NAS TRANSPORT message in a NAS transport procedure.

[0260] In addition, in the NW-initiated MM procedure, when the NW transmits one or more of the seventh to eleventh identification information to the UE, the NW may recognize that the UE supports store-and-forward communication from another procedure, subscription information of the UE, etc. In other words, for example, when the NW or the AMF recognizes that the UE supports store-and-forward communication, the NW or the AMF may transmit a message including one or more of the seventh to eleventh identification information to the UE.

[0261] In addition, the network may indicate that it supports store-and-forward communication by sending a message to the UE that does not include the twelfth identification information but includes one or more of the seventh to eleventh identification information, or a UE that receives a message that does not include the second identification information but includes the third identification information may recognize that the network supports store-and-forward communication.

[0262] As an example of a mobility management procedure, a registration procedure will be described below with reference to FIG.

[0263] 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 it is powered on. In other words, if the UE is in the unregistered 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.

[0264] 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.

[0265] 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.

[0266] 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.

[0267] 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.

[0268] 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.

[0269] 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.

[0270] 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.

[0271] 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.

[0272] Here, the UE may transmit the second identification information in the registration request message.

[0273] 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.

[0274] 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.

[0275] 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).

[0276] An AMF that receives a registration request message including second identification information from a UE may recognize and store what the identification information included in the registration request message means. That is, the AMF may recognize and store the UE's capability indicating whether the UE supports store-and-forward communication. In this specification, unless otherwise specified, the second identification information may be the UE's capability information indicating that the UE supports store-and-forward communication.

[0277] 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.

[0278] 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.

[0279] 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.

[0280] 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.

[0281] 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.

[0282] The AMF may include any one or more of the second to sixth and twelfth identification information in the registration acceptance message and transmit it. Note that the AMF of this embodiment may be installed on a satellite or in a terrestrial core network. Furthermore, the AMF of this embodiment may include the twelfth identification information indicating that it supports store-and-forward communication in the registration acceptance message.

[0283] 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.

[0284] Furthermore, whether or not to include any one or more of the second to sixth and twelfth 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.

[0285] 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.

[0286] 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.

[0287] 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.

[0288] 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.

[0289] Here, a UE that receives a registration accept message from an AMF may recognize and store the information indicated by any one or more of the second to sixth and twelfth identification information included in the received registration accept message. Also, in this specification, the registration accept message may include a twelfth identification information indicating that the network or the satellite to which the UE is connected supports store-and-forward communication.

[0290] 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).

[0291] 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.

[0292] 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.

[0293] 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.

[0294] 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.

[0295] The procedure in FIG. 6(B) may be started when the procedure in FIG. 6(A) is stopped.

[0296] 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.

[0297] The UE may also complete the registration procedure based on receiving a registration accept message or a registration reject message.

[0298] 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.

[0299] 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.

[0300] The UE may recognize the content of the above identification information by receiving a registration acceptance message or a registration rejection message.

[0301] The behavior to be performed when each piece of identification information is received may be performed based on the received identification information.

[0302] Examples of mobility management procedures that take into account the use of store-and-forward functionality or communication are described in Chapter 5.

[0303] 4.3. Session Management Procedures 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.

[0304] 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.

[0305] 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.

[0306] 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.

[0307] 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.

[0308] Next, each of the above-mentioned session management procedures will be explained.

[0309] 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 change 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 response message to the session management request message from the SMF to the UE (S706) may be executed.

[0310] 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.

[0311] Next, each step of the session management procedure will be explained.

[0312] 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.

[0313] Here, the UE in this embodiment may include the second identification information in a session management (SM) request message and transmit it to the satellite. In this specification, unless otherwise specified, the second identification information included in the SM request message by the UE may be information indicating that the UE supports store-and-forward communication.

[0314] Here, in the UE-initiated SM procedure, the first message including the second identity sent by the UE to the network is a session management request message, which 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 the network-requested PDU session modification procedure, the network-requested PDU session release procedure, or the PDU session authentication and authorization procedure, the transmission of the session management request message from the UE to the SMF may not be performed.

[0315] 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.

[0316] Next, the SMF that receives the session management request message from the UE may perform processing (A) or send a response message to the session management request to the UE (S706).

[0317] Here, the response message to the session management request sent by the SMF to the UE may include one or more of the third to sixth and twelfth identification information. In this specification, unless otherwise specified, the twelfth identification information included by the UE in the SM request message may be information indicating that the network or satellite supports store-and-forward communication.

[0318] 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.

[0319] 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.

[0320] 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.

[0321] 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.

[0322] 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 in the PDU session establishment procedure, it is not necessary to perform the process of (A).

[0323] 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).

[0324] 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.

[0325] 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.

[0326] 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.

[0327] Furthermore, the UE that sent the PDU session establishment request message may start timer T3580 as a session management timer.

[0328] 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.

[0329] 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.

[0330] 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.

[0331] 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.

[0332] Furthermore, the NW may include one or more of the seventh to eleventh identification information in an initial message initiating a NW-initiated SM procedure and transmit the same to the UE, or the UE may receive a message from the NW including one or more of the seventh to eleventh identification information. Furthermore, a UE that supports store-and-forward communication and receives one or more of the seventh to eleventh identification information from the NW may recognize that the NW supports store-and-forward communication and may store each identification information.

[0333] In addition, in the NW-initiated SM procedure, when the NW transmits one or more of the seventh to eleventh identification information to the UE, the NW may recognize that the UE supports store-and-forward communication from another procedure, subscription information of the UE, etc. In other words, for example, when the NW or the AMF recognizes that the UE supports store-and-forward communication, the NW or the AMF may transmit a message including one or more of the seventh to eleventh identification information to the UE.

[0334] In addition, the network may indicate that it supports store-and-forward communication by sending a message to the UE that does not include the twelfth identification information but includes one or more of the seventh to eleventh identification information, or a UE that receives a message that does not include the second identification information but includes the third identification information may recognize that the network supports store-and-forward communication.

[0335] The behavior to be performed when each piece of identification information is received may be performed based on the received identification information.

[0336] Examples of session management procedures that take into account the use or communication of store-and-forward functionality are described in Section 5.

[0337] 5. Embodiment 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. In addition, in this chapter, each embodiment described in this chapter will also be referred to as each embodiment of this chapter, or simply each embodiment.

[0338] Each embodiment in this chapter may be an embodiment in which the UE and satellite support a store-and-forward function or store-and-forward communication, and / or the satellite has storage for store-and-forward communication, and / or the UE initiates or performs a UE-initiated mobility management procedure, a UE-initiated session management procedure, or a MO (mobile originated) procedure or user data transmission within the satellite access range.

[0339] Furthermore, an objective of each embodiment described in this chapter is to enable the UE to recognize the state of storage for store-and-forward communication provided in the satellite before performing or starting various UE manual procedures or MO (mobile originated) communication, when the UE and satellite support store-and-forward functions or communication. This allows the UE to not perform MO communication depending on the state of the satellite's storage, thereby reducing unnecessary signaling that is transmitted and received without considering the state of the satellite's storage.

[0340] Furthermore, unless otherwise specified, each embodiment described in each section of this chapter may be executed individually and independently, or may be executed by combining the procedures of one or more embodiments described in each section, or may be executed in any order.

[0341] More specifically, for example, the UE and satellite of this embodiment may execute the first embodiment before each procedure in the second to fifth embodiments or before transmitting and receiving user data. Alternatively, for example, the UE and satellite of this embodiment may execute the first embodiment before each procedure in the second to fifth embodiments or before transmitting and receiving user data. Alternatively, the UE and satellite of this embodiment may execute each procedure in the second to fifth embodiments based on the execution result of the first embodiment executed immediately before each procedure.

[0342] Also, for example, the UE and the satellite may execute the third or fourth embodiment after executing the second embodiment. More specifically, after executing the first embodiment and completing the registration procedure and / or PDU session establishment procedure in the second embodiment, the UE and the satellite may execute the first embodiment and then execute the third or fourth embodiment.

[0343] Also, for example, the UE and the satellite may execute the third embodiment and the fourth embodiment together. That is, the third embodiment may be executed before the period when the satellite access provided by the satellite is unavailable, and the fourth embodiment may be executed after the period when the satellite access provided by the satellite is unavailable. Furthermore, in this case, the fourth embodiment may be executed taking into account the states of the UE, the satellite, and the base station device and core network device mounted on the satellite after the third embodiment is executed.

[0344] Each embodiment will be described below.

[0345] 5.1. First embodiment A first embodiment of this example will be described. Hereinafter, in this section, the first embodiment will also be referred to as this embodiment.

[0346] The UE of this embodiment may be configured to receive, via the satellite or a base station of the satellite, broadcast information or system information indicating the status of storage for store-and-forward communication provided in the satellite, and determine the behavior of the UE based on the broadcast information. In this specification, the broadcast information is also simply referred to as system information.

[0347] In addition, the UE, satellite, and each device equipped in the satellite in this embodiment may support store-and-forward communication using storage equipped in the satellite unless otherwise specified. Furthermore, this embodiment may be executed regardless of the registration status of the UE to the network. That is, the UE may be executed in a state where it is not registered to the network via the base station device equipped in the satellite, may be executed in a state where it is registered to the network, or may be executed in a state where it is registered to the network and has established a PDU session.

[0348] Here, the information indicating the state of the storage for store-and-forward communication may be first identification information, and the notification information may be a MIB (Master Information Block) and / or a SIB (System Information Block).

[0349] Furthermore, the first identification information may be information that is included in system information and transmitted by a satellite or a base station device provided by the satellite and received by the UE. In other words, for example, the UE may receive and store system information that indicates the first identification information or that includes the first identification information and that is transmitted by a satellite or a base station device provided by the satellite.

[0350] Furthermore, if the UE has already received or stored information indicating the status of the storage for store-and-forward communication provided by the satellite, the UE may overwrite or update the stored information with the content indicated by the newly received first identification information.

[0351] Next, the UE may receive and store the first identification information via a satellite or a base station provided by the satellite and perform steps to determine the behavior of the UE based on the content of the first identification information.

[0352] More specifically, for example, a UE that receives first identification information indicating that storage for store-and-forward communication provided in a satellite is available or permitted to be used may recognize that it is not possible or permitted to execute, start or continue a UE-initiated mobility management procedure, or a UE-initiated session management procedure, or MO communication, or transmission of user data via the satellite or a base station device provided in the satellite, or may transition to a mode in which it is possible to start store-and-forward communication using storage provided in the satellite.

[0353] Alternatively, for example, a UE that receives first identification information indicating that storage for store-and-forward communication provided by a satellite is unavailable or is not authorized for use may recognize that it is not possible or authorized to execute, start or continue a UE-initiated mobility management procedure, or a UE-initiated session management procedure, or MO communication, or transmission of user data via the satellite or a base station device provided by the satellite, and may not transition to a mode in which it is possible to start store-and-forward communication using storage provided by the satellite.

[0354] This embodiment may be performed before or immediately before each procedure in the second to fifth embodiments described below, or in each of the embodiments. Furthermore, the UE may or may not perform each procedure in the second to fourth embodiments, or in each of the embodiments, based on the UE's determination in this embodiment.

[0355] More specifically, for example, in this embodiment, a UE that receives first identification information indicating that storage for store-and-forward communication provided on a satellite is available or authorized for use may perform each procedure in the second to fourth embodiments, or each of the embodiments.

[0356] Or, for example, in this embodiment, a UE that receives first identification information indicating that the storage for store-and-forward communication provided by the satellite is not available or is not authorized for use does not need to perform each procedure in the second to fourth embodiments or each embodiment.

[0357] As described above, the UE of this embodiment receives system information including, for example, first identification information indicating the status of storage for store-and-forward communication provided in the satellite. Furthermore, the UE that has received the first identification information from the satellite may determine, based on the received first identification information, whether it is possible to execute a mobility management procedure, a session management procedure, or transmission of user data via the satellite as communication using the store-and-forward function or store-and-forward communication.

[0358] Here, if the first identification information included in the system information received by the UE from the satellite indicates that the satellite's storage capacity for store-and-forward communication is full, and / or that the satellite's storage for store-and-forward communication is unavailable, and / or that the satellite does not have valid store-and-forward communication storage available to the UE, and / or that the UE attempting communication is not authorized to use the satellite's storage for store-and-forward communication, the UE may determine that store-and-forward communication using the satellite's storage is not possible via the satellite. The UE that made this determination may not execute or start a mobility management procedure, a session management procedure, or a user data transmission procedure via the satellite. Alternatively, the UE that made this determination may abort a mobility management procedure, a session management procedure, or a user data transmission procedure currently being executed via the satellite.

[0359] Alternatively, if the first identification information included in the system information received by the UE from the satellite indicates that the satellite's storage capacity for store-and-forward communication is available, and / or that the satellite's storage for store-and-forward communication is available, and / or that the satellite has valid store-and-forward communication storage that the UE can use, and / or that the UE attempting communication is authorized to use the satellite's storage for store-and-forward communication, the UE may determine that store-and-forward communication using the satellite's storage is possible. The UE that made this determination may execute or start a mobility management procedure, a session management procedure, or a user data transmission procedure via the satellite. Alternatively, the UE that made this determination may continue a mobility management procedure, a session management procedure, or a user data transmission procedure currently being executed via the satellite.

[0360] Furthermore, if the satellite and the UE support a store-and-forward function and the UE receives from the satellite first identification information indicating that the satellite's storage is unavailable, the UE and the satellite may execute a mobility management procedure, a session management procedure, or a user data transmission procedure as store-and-forward communication that does not use the satellite's storage.

[0361] As described above, the UE of this embodiment receives system information including first identification information indicating the status of storage for store-and-forward communication provided in the satellite from a satellite or a base station device provided in the satellite. Based on the first identification information received from the satellite, the UE may determine whether to execute or start a mobility management procedure, a session management procedure, or a user data transmission / reception procedure via the satellite.

[0362] Furthermore, if the UE determines not to perform or initiate a mobility management procedure, or a session management procedure, or a user data transmission procedure via a satellite, the UE may not initiate transmission of a message for the mobility management procedure, or the session management procedure, or the user data transmission procedure via a satellite.

[0363] Furthermore, if the UE determines to perform or initiate a mobility management procedure, or a session management procedure, or a user data transmission procedure via a satellite, the UE may initiate transmission of a message for the mobility management procedure, or the session management procedure, or the user data transmission procedure via a satellite.

[0364] [5.2. Second embodiment] A second embodiment of this example will be described. In this section, the second embodiment will also be referred to as this embodiment.

[0365] This embodiment may be executed after the first embodiment is executed, or may be executed based on the determination of the UE in the first embodiment. Alternatively, this embodiment may be executed independently of the first embodiment. Furthermore, the UE, satellite, and each device provided on the satellite in this embodiment may support store-and-forward communication using storage provided on the satellite, unless otherwise specified.

[0366] Furthermore, the satellite of this embodiment may include a base station device, and / or a core network device for mobility management, and / or a core network device for session management. Here, the core network device for mobility management may be an AMF and / or an MME. Here, the core network device for session management may be an SMF and / or a PGW (PGW-C).

[0367] In this embodiment, when referring to multiple satellites, the satellites are also referred to as satellite #1, satellite #2, and satellite #3, respectively. Here, satellite #1, satellite #2, and satellite #3 may each be different satellites.

[0368] In this embodiment, the UE may perform a mobility management procedure or a session management procedure via a satellite. Details of the mobility management procedure or the session management procedure may be as described in Chapter 4.

[0369] More specifically, for example, the UE may transmit second identification information indicating that it supports the store-and-forward function in a request message for initiating a mobility management procedure or a session management procedure, and determine whether the satellite, and / or the base station device provided in the satellite, and / or the base station device provided in the satellite, is capable of or is permitted to use the storage provided in the satellite.

[0370] Here, if the satellite, and / or the base station device provided by the satellite, and / or the base station device provided by the satellite that receives the request message including the second identification information determines that it is possible or permitted to use the storage provided by the satellite, it may continue and process the mobility management procedure or session management procedure based on the request message received from the UE.

[0371] Alternatively, if the satellite, and / or the base station device provided in the satellite, and / or the base station device provided in the satellite that receives the request message including the second identification information determines that it is not possible or permitted to use the storage provided in the satellite, it may send a rejection message including any one or more of the second to twelfth identification information to the UE in response to the request message received from the UE, and may cancel or interrupt the mobility management procedure or the session management procedure.

[0372] In the following, an example in which the procedure executed by the UE in this embodiment is a registration procedure will be described.

[0373] The UE of this embodiment initiates registration procedure #1 by transmitting a registration request message including second identification information, which is capability information indicating that the UE supports store-and-forward communication, to the base station device of satellite #1 and / or the core network device of satellite #1. Alternatively, the UE of this embodiment may transmit a registration request message including second identification information, which is capability information indicating that the UE supports store-and-forward communication, to the base station device of satellite #1 and / or the core network device of satellite #1 during the registration procedure.

[0374] Upon receiving the registration request message including the second identification information from the UE, the satellite #1, its base station device, and / or its core network device may recognize that the UE supports the store-and-forward function. Furthermore, the satellite #1 may determine whether its storage is available and / or permitted for store-and-forward communication with the UE.

[0375] Here, if satellite #1 determines that the storage provided by satellite #1 is not available and / or not permitted for store-and-forward communication with the UE, i.e., if the storage provided by the satellite for store-and-forward communication is not available, satellite #1 may send a message to the UE including third and / or fourth identification information.

[0376] Here, a UE that receives a message including the third and / or fourth identification information from satellite #1 may store the received third and / or fourth identification information, may recognize the content indicated by the third and / or fourth identification information, or may cancel or interrupt registration procedure #1.

[0377] More specifically, for example, the UE may recognize, based on the third identification information received from satellite #1, that the storage for store-and-forward communication provided in satellite #1 is unavailable. The UE may also set a back-off timer for the UE with a value indicated by the fourth identification information received from the satellite, and start or execute the back-off timer set with the value indicated by the fourth identification information. Here, the back-off timer value indicated by the fourth identification information may be the value of a mobility management timer indicating the time until a registration procedure is retried. Subsequently, when the back-off timer based on the fourth identification information expires, the UE may start or execute a new registration procedure, registration procedure #2.

[0378] Alternatively, if satellite #1 determines that the storage provided by satellite #1 is not available and / or not permitted for store-and-forward communication with the UE, i.e., if the storage provided by the satellite for store-and-forward communication is not available, satellite #1 may send a message to the UE including the third and / or fifth identification information.

[0379] Here, a UE that receives a message including the third and / or fifth identification information from satellite #1 may store the received third and / or fifth identification information, may recognize the content indicated by the third and / or fifth identification information, or may cancel or interrupt registration procedure #1.

[0380] More specifically, for example, the UE may recognize, based on the third identification information received from satellite #1, that the storage for store-and-forward communication provided in satellite #1 is unavailable. Furthermore, based on the fifth identification information received from satellite #1, the UE may recognize that satellite #1, and / or the base station device provided in satellite #1, and / or the core network device provided in satellite #1, have requested that the UE perform a registration procedure via a satellite other than satellite #1. Subsequently, the UE may initiate or perform a registration procedure #3 via satellite #2, other than satellite #1, based on the fifth identification information.

[0381] Alternatively, if satellite #1 determines that the storage provided by satellite #1 is not available and / or not permitted for store-and-forward communication with the UE, i.e., if the storage provided by the satellite for store-and-forward communication is not available, satellite #1 may send a message to the UE including the third and / or sixth identification information.

[0382] Here, a UE that receives a message including the third and / or sixth identification information from satellite #1 may store the received third and / or sixth identification information, may recognize the content indicated by the third and / or fifth identification information, or may cancel or interrupt registration procedure #1.

[0383] More specifically, for example, the UE may recognize, based on the third identification information received from satellite #1, that the storage for store-and-forward communication provided by satellite #1 is unavailable. Furthermore, based on the sixth identification information received from satellite #1, the UE may recognize that satellite #1, a base station device provided in satellite #1, and / or a core network device provided in satellite #1 have requested that the UE initiate or execute a registration procedure after returning from outside the coverage area of ​​the satellite access provided by satellite #1 to within coverage. Subsequently, based on the sixth identification information, the UE may initiate or execute a registration procedure #2 after returning from outside the coverage area of ​​the satellite access provided by satellite #1 to within coverage. Here, the period from outside the coverage area of ​​the satellite access provided by the satellite to returning to within coverage area may be an unavailable period, and the timing at which the UE returns from outside the coverage area of ​​the satellite access provided by the satellite to within coverage area may coincide with the timing at which the unavailable period ends.

[0384] As described above, during registration procedure #1, the UE of this embodiment transmits a registration request message to the core network device of satellite #1, the message including second identification information, which is capability information indicating that the UE supports store-and-forward communication. If the satellite's storage for store-and-forward communication is unavailable, the UE receives a registration rejection message from the core network device of the satellite, the registration rejection message including third identification information, which is a rejection reason value indicating that the storage is unavailable, and fourth identification information, which corresponds to the third control information and is a back-off timer value for when the UE retries the registration procedure. Upon receiving the registration rejection message including the fourth identification information, the UE may set a back-off timer to the value indicated by the fourth identification information, start the back-off timer, and start the second registration procedure after the back-off timer expires.

[0385] Furthermore, if the UE receives a registration rejection message including a third identification and a fifth identification indicating that the core network device equipped with the satellite requests the UE to perform or initiate a mobility management procedure or a session management procedure via another satellite other than satellite #1, the UE may initiate a registration procedure #3 via satellite #2, another satellite other than satellite #1, selected based on the fifth identification.

[0386] Furthermore, if the UE receives a registration rejection message including the third identification information and the sixth identification information indicating that the network requests the UE to initiate a registration procedure via satellite #1 access after the UE returns from outside the range of satellite #1 access to within the range of satellite #1 access, the UE may initiate a second registration procedure #2 based on the sixth identification information after the UE returns from outside the range of satellite #1 access to within the range of satellite #1 access.

[0387] 5.3. Third embodiment A third embodiment of this example will be described. In this section, the third embodiment will also be referred to as this embodiment.

[0388] This embodiment may be an embodiment in which the UE and the satellite (the satellite, and / or the base station device provided in the satellite, and / or the core network device provided in the satellite) start in a state in which they are capable of transmitting and receiving user data via store-and-forward.

[0389] Unless otherwise specified, the transfer of user data in this embodiment may be MO communication from the UE to the satellite.

[0390] Furthermore, the transmission of user data from the UE to the satellite is not limited to transmission via a PDU session, but may be transmission of data using EPS or 5GS optimization of CIoT (Control Plane Cellular Internet of Things). Transmission of user data from the UE using EPS or 5GS optimization of CP CIoT may be performed via a base station included in the satellite and an MME or AMF included in the satellite, with the user data included in a control plane message (e.g., a service request message).

[0391] More specifically, this embodiment may be an embodiment that starts when the UE completes the registration procedure by sending, during an initial registration procedure or a registration update procedure, a registration request message including second identification information indicating that the UE supports the store-and-forward function or store-and-forward communication, and receiving from the network a registration accept message including twelfth identification information indicating that the UE supports the store-and-forward function or store-and-forward communication.

[0392] In other words, this embodiment may be an embodiment that starts in a state where the registration procedure and the PDU session establishment procedure are completed, or in a state where a PDU session that can be used for store-and-forward communication is established. Furthermore, in the registration procedure and / or the PDU session establishment procedure, the second identification information and / or the twelfth identification information may be transmitted and received, and the UE and each device may recognize that the UE, the satellite, the base station device provided in the satellite, and / or the core network device provided in the satellite supports store-and-forward communication, and the satellite may further include storage for store-and-forward communication. Furthermore, the PDU session established in this embodiment may be a PDU session for store-and-forward communication.

[0393] This embodiment may be implemented in conjunction with the fourth embodiment. That is, this embodiment may be implemented before a period in which satellite access provided by a satellite is unavailable, and the fourth embodiment may be implemented after the period in which satellite access provided by the satellite is unavailable. In this case, the fourth embodiment may be implemented taking into consideration the states of the UE, the satellite, and the base station device and core network device mounted on the satellite after the implementation of this embodiment.

[0394] More specifically, the UE in this embodiment first transmits user data to satellite #1 or a base station device included in satellite #1. Upon receiving the user data from the UE, satellite #1 determines or judges whether it is possible to store the user data in storage included in satellite #1, and / or whether it is possible to use the storage included in satellite #1, and / or whether it is permitted to use the storage included in satellite #1.

[0395] Here, if satellite #1 determines or decides that it is not possible to store user data received from the UE in the storage provided by satellite #1, and / or that it is not possible to use the storage provided by satellite #1, and / or that it is not permitted to use the storage provided by satellite #1, satellite #1 may send a message including the seventh identification information to the UE via the base station device provided by satellite #1.

[0396] Here, the seventh identification information transmitted by satellite #1 to the UE may be included in any message transmitted and received during the NW-initiated MM procedure. More specifically, the MM message transmitted by satellite #1 to the UE including the seventh identification information may be a deregistration request message in the deregistration procedure, and / or a configuration update command message in the UE configuration update procedure, and / or a DL NAS TRANSPORT message in the NAS transport procedure.

[0397] Alternatively, the seventh identification information transmitted by satellite #1 to the UE may be included in any message transmitted or received during the NW-initiated SM procedure. More specifically, the SM message transmitted by satellite #1 to the UE including the seventh identification information may be a PDU session release request message in the NW-initiated PDU session release procedure and / or a PDU session modification request message in the NW-initiated PDU session modification procedure.

[0398] Furthermore, a UE that receives a message including the seventh identification information from satellite #1 may suspend or stop the user data transmission that the UE was performing based on the seventh identification information.

[0399] Alternatively, if satellite #1 determines or decides that it is not possible to store user data received from the UE in the storage provided by satellite #1, and / or that it is not possible to use the storage provided by satellite #1, and / or that it is not permitted to use the storage provided by satellite #1, and if there is or can indicate to the UE another satellite other than satellite #1 with which the UE can perform or continue store-and-forward communication, satellite #1 may send a message including the seventh and / or eighth identification information to the UE via the base station equipment provided by satellite #1.

[0400] Here, the seventh and / or eighth identification information transmitted by satellite #1 to the UE may be included in any message transmitted and received during the NW-initiated MM procedure. More specifically, the MM message transmitted by satellite #1 to the UE including the seventh and / or eighth identification information may be a deregistration request message in the deregistration procedure, and / or a configuration update command message in the UE configuration update procedure, and / or a DL NAS TRANSPORT message in the NAS transport procedure.

[0401] Alternatively, the seventh and / or eighth identification information transmitted by satellite #1 to the UE may be included in any message transmitted or received during the NW-initiated MM procedure. More specifically, the SM message transmitted to the UE including the eighth identification information of satellite #1 may be a PDU session release request message in the NW-initiated PDU session release procedure and / or a PDU session modification request message in the network-initiated PDU session modification procedure.

[0402] Furthermore, a UE that receives a message including the seventh and / or eighth identification information from satellite #1 may suspend or stop the user data transmission that the UE has been performing via satellite #1 based on the seventh and / or eighth identification information, and may resume, start, or perform procedures for user data transmission and / or user data transmission via satellite #2, which is different from satellite #1, based on the eighth identification information. Here, each procedure for user data transmission may be, for example, a registration procedure and / or a PDU session establishment procedure.

[0403] Alternatively, if satellite #1 determines or decides that it is not possible to store user data received from the UE in the storage provided by satellite #1, and / or that it is not possible to use the storage provided by satellite #1, and / or that it is not permitted to use the storage provided by satellite #1, and decides to request or indicate to the UE that it should resume transmitting user data that it was performing after returning from outside the range of satellite access provided by satellite #1 to within range, satellite #1 may send a message including the seventh and / or ninth identification information to the UE via its own base station device.

[0404] Here, the seventh and / or ninth identification information transmitted by satellite #1 to the UE may be included in any message transmitted and received during the NW-initiated MM procedure. More specifically, the MM message transmitted by satellite #1 to the UE including the seventh and / or ninth identification information may be a deregistration request message in the deregistration procedure, and / or a configuration update command message in the UE configuration update procedure, and / or a DL NAS TRANSPORT message in the NAS transport procedure.

[0405] Alternatively, the seventh and / or ninth identification information transmitted by satellite #1 to the UE may be included in any message transmitted or received during the NW-initiated SM procedure. More specifically, the SM message transmitted to the UE including the eighth identification information of satellite #1 may be a PDU session release request message in the NW-initiated PDU session release procedure and / or a PDU session modification request message in the network-initiated PDU session modification procedure.

[0406] Furthermore, a UE that receives a message including the seventh and / or ninth identification information from satellite #1 may suspend or stop the transmission of user data that the UE was performing via satellite #1 based on the seventh and / or ninth identification information, and may resume or start the transmission of user data that the UE was performing before the unavailable period based on the ninth identification information after the UE returns from outside the range of satellite access provided by satellite #1 to within range (i.e., after the unavailable period).

[0407] In addition, in this embodiment, during the NW-initiated procedure, the transmission of an MM message and / or an SM message including one or more of the seventh to ninth identification information to the UE may be performed at any timing by the satellite and each device equipped on the satellite, and the UE may perform the behavior described in this embodiment based on the identification information received from the satellite.

[0408] As described above, the UE of this embodiment transmits user data to a base station device provided in satellite #1, and if the storage for store-and-forward communication provided in the satellite is unavailable, the UE receives a message including seventh identification information from the core network device provided in the satellite via the base station device provided in the satellite, indicating that the storage for store-and-forward communication provided in the satellite is unavailable, and the UE may stop transmitting the user data based on the seventh identification information.

[0409] Furthermore, if the UE receives a message from the satellite including an eighth identification information indicating that the satellite or a core network device provided by the satellite requests the UE to transmit user data via a base station device provided by a satellite other than the base station provided by satellite #1, the UE may stop transmitting user data based on the eighth identification information and start transmitting user data via a base station device provided by a satellite other than satellite #1.

[0410] Furthermore, if the UE receives a message from the satellite including a ninth identification information indicating that the satellite or a core network device provided by the satellite requests the UE to resume transmitting user data after the UE returns from outside the satellite access range to within the satellite access range, the UE may stop transmitting user data based on the ninth identification information, and start or resume transmitting user data after the UE returns from outside the satellite access range provided by the satellite to within the satellite access range.

[0411] [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.

[0412] This embodiment may be an embodiment in which the UE and the satellite (the satellite, and / or the base station device provided in the satellite, and / or the core network device provided in the satellite) start in a state in which they are capable of transmitting and receiving user data via store-and-forward.

[0413] Unless otherwise specified, the transfer of user data in this embodiment may be MO communication from the UE to the satellite.

[0414] Furthermore, the transmission of user data from the UE to the satellite is not limited to transmission via a PDU session, but may be transmission of data using EPS or 5GS optimization of CIoT (Control Plane Cellular Internet of Things). Transmission of user data from the UE using EPS or 5GS optimization of CP CIoT may be performed via a base station included in the satellite and an MME or AMF included in the satellite, with the user data included in a control plane message (e.g., a service request message).

[0415] More specifically, this embodiment may be an embodiment that starts when the UE completes the registration procedure by sending, during an initial registration procedure or a registration update procedure, a registration request message including second identification information indicating that the UE supports the store-and-forward function or store-and-forward communication, and receiving from the network a registration accept message including twelfth identification information indicating that the UE supports the store-and-forward function or store-and-forward communication.

[0416] In other words, this embodiment may be an embodiment that starts in a state where the registration procedure and the PDU session establishment procedure are completed, or in a state where a PDU session that can be used for store-and-forward communication is established. Furthermore, in the registration procedure and / or the PDU session establishment procedure, the second identification information and / or the twelfth identification information may be transmitted and received, and the UE and each device may recognize that the UE, the satellite, the base station device provided in the satellite, and / or the core network device provided in the satellite supports store-and-forward communication, and the satellite may further include storage for store-and-forward communication. Furthermore, the PDU session established in this embodiment may be a PDU session for store-and-forward communication.

[0417] This embodiment may also be implemented in conjunction with the third embodiment. That is, the third embodiment may be implemented before a period in which satellite access provided by a satellite is unavailable, and the present embodiment may be implemented after the period in which satellite access provided by the satellite is unavailable. Furthermore, in this case, this embodiment may be implemented taking into account the states of the UE, the satellite, and the base station device and core network device mounted on the satellite after the implementation of the third embodiment. More specifically, for example, transmission of user data that was stopped or interrupted in the third embodiment may be resumed by this embodiment.

[0418] More specifically, the UE in this embodiment first transmits user data to satellite #1 or a base station device included in satellite #1. Upon receiving the user data from the UE, satellite #1 determines or judges whether it is possible to store the user data in storage included in satellite #1, and / or whether it is possible to use the storage included in satellite #1, and / or whether it is permitted to use the storage included in satellite #1.

[0419] Here, if the satellite determines or determines that it is not possible to store user data received from the UE in the storage provided by the satellite, and / or that it is not possible to use the storage provided by satellite #1, and / or that it is not permitted to use the storage provided by satellite #1, satellite #1 may send a message including the seventh identification information to the UE via the base station device provided by satellite #1.

[0420] Here, the seventh identification information transmitted by satellite #1 to the UE may be included in any message transmitted and received during the NW-initiated MM procedure. More specifically, the MM message transmitted by satellite #1 to the UE including the seventh identification information may be a deregistration request message in the deregistration procedure, and / or a configuration update command message in the UE configuration update procedure, and / or a DL NAS TRANSPORT message in the NAS transport procedure.

[0421] Alternatively, the seventh identification information transmitted by satellite #1 to the UE may be included in any message transmitted or received during the NW-initiated SM procedure. More specifically, the SM message transmitted by satellite #1 to the UE including the seventh identification information may be a PDU session release request message in the NW-initiated PDU session release procedure and / or a PDU session modification request message in the network-initiated PDU session modification procedure.

[0422] Furthermore, when the UE receives a message including the seventh identification information from the satellite, the UE may suspend or stop the transmission of user data that the UE was performing based on the seventh identification information.

[0423] Subsequently, the UE of this embodiment, which has suspended or stopped transmitting user data, receives a message including the tenth and / or eleventh identification information from the satellite. Here, the transmission and reception of the message including the tenth and / or eleventh identification information may be similar to the transmission and reception of the message including the seventh identification information described above, and may be transmitted from the satellite to the UE and received by the UE.

[0424] Here, the UE receiving the message including the tenth and / or eleventh identification information may start or resume transmission of user data that has been stopped or suspended to the UE based on the tenth identification information. Also, as described above, the stopping or suspension of user data transmission in the UE may be based on the seventh identification information received from the satellite.

[0425] And / or, a UE receiving a message including the tenth and / or eleventh identification information may resume, based on the eleventh identification information, the transfer or transmission of user data that failed when execution was stopped or interrupted in the UE. Also, as mentioned above, the stopping or interruption of user data transmission in the UE may be based on the seventh identification information received from the satellite.

[0426] In this embodiment, during the NW-initiated procedure, the transmission of the MM message and / or the SM message including one or more of the seventh, tenth, and eleventh identification information to the UE may be performed at any timing by the satellite and each device included in the satellite, and the UE may perform the behavior described in this embodiment based on the identification information received from the satellite. More specifically, for example, the tenth and / or eleventh identification information may be transmitted from the satellite to the UE after or immediately after the unavailable period.

[0427] As described above, the UE of this embodiment transmits user data to a base station device provided in a satellite, and when the storage for store-and-forward communication provided in the satellite is unavailable, the UE may receive from the satellite a first message including seventh identification information indicating that the storage for store-and-forward communication provided in the satellite is unavailable, and the UE may stop transmitting the user data based on the seventh identification information. Here, the first message may be a response message of a UE-initiated MM procedure or a UE-initiated SM procedure.

[0428] Furthermore, the UE receives a second message from the satellite, the second message including tenth identification information indicating that storage for store-and-forward communication has become available and / or eleventh identification information indicating user data whose transfer has failed during the UE's user data transmission, and the UE may start or resume the transmission of the user data based on the tenth identification information, or may retransmit or transmit the user data whose transmission has failed based on the eleventh identification information. Here, the second message may be a message of a NW-initiated MM procedure or a NW-initiated SM procedure. 6. Variations The program that runs on the device 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 the 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.

[0429] 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.

[0430] 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.

[0431] 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 stationary or non-movable electronic devices installed indoors or outdoors, such as terminal devices or communication devices for AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0432] 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. [Explanation of symbols]

[0433] 1. Mobile communication systems 10 UE_A 30 PGW-U 32 PGW-C 35 SGW 40 MME 45 eNB 50 HSS 60 PCRF 80 Access Network_A (E-UTRAN) 90 Core Network_A 120 Access Network_B (5G AN) 122 gNB 130 UPF 132 SMF 140 AMF 150 UDM 160 PCF 190 Core Network_B 235 UPF_A 239 UPF_C

Claims

1. A UE (User Equipment) including a transceiver unit and a control unit, the transceiver receives system information including first control information from a base station device included in the satellite; the first control information is information indicating a state of storage for store-and-forward communication provided in the satellite, the control unit determines whether to execute or start a mobility management procedure, a session management procedure, or a user data transmission / reception procedure via the satellite based on the first control information. A UE characterized by:

2. When the control unit determines not to execute or start a mobility management procedure, a session management procedure, or a user data transmission procedure via the satellite, the transceiver does not initiate transmission of a message for a mobility management procedure, a session management procedure, or a user data transmission procedure via the satellite; 2. The UE of claim 1 .

3. When the control unit determines to execute or start a mobility management procedure, a session management procedure, or a user data transmission procedure via the satellite, the transceiver initiates transmission of a message for a mobility management procedure, a session management procedure, or a user data transmission procedure via the satellite; 2. The UE of claim 1 .

4. A UE (User Equipment) including a transceiver unit and a control unit, The transceiver unit transmits a registration request message including second control information to a core network device included in the first satellite during the first registration procedure; the second control information is capability information indicating that the UE supports store-and-forward communication; If the storage for store-and-forward communication provided in the satellite is not available, the transceiver receives a registration rejection message including third and fourth control information from a core network device provided in the satellite; the third control information is a rejection reason value indicating that the storage is unavailable; the fourth control information is a back-off timer value corresponding to the third control information when the UE retries the registration procedure; The control unit setting a back-off timer to a value indicated by the fourth control information, and starting the back-off timer; initiating a second registration procedure after the back-off timer expires; A UE characterized by:

5. When the transceiver receives a registration rejection message including the third control information and the fifth control information, the control unit starts a third registration procedure via a satellite different from the first satellite, selected based on the fifth control information; The fifth control information is information indicating that a core network device included in the satellite requests the UE to perform or start a mobility management procedure or a session management procedure via a satellite different from the first satellite.

5. The UE of claim 4.

6. When the transceiver receives a registration rejection message including the third control information and the sixth control information, the control unit starts the second registration procedure after the UE returns from outside the access range of the first satellite to within the access range of the first satellite, based on the sixth control information. the sixth control information is information indicating that the network requests the UE to start a registration procedure via the first satellite access after the UE returns from outside the first satellite access range to within the first satellite access range; 5. The UE of claim 4.

7. A UE (User Equipment) including a transceiver unit and a control unit, the transceiver unit transmits user data to a base station device included in a first satellite; When the storage for store-and-forward communication provided in the satellite is unavailable, the transceiver receives a message including seventh control information from a core network device provided in the satellite via a base station device provided in the satellite; the seventh control information is information indicating that a storage for store-and-forward communication provided in the satellite is unavailable; and the control unit stops transmission of user data based on the seventh control information. A UE characterized by:

8. When the transceiver receives the message from the satellite, the message further includes eighth control information, the control unit stops transmission of user data based on the eighth control information and starts transmission of user data via a base station device included in a satellite different from the first satellite; The eighth control information is information indicating that the satellite or a core network device included in the satellite requests the UE to transmit user data via a base station device included in another satellite different from the base station included in the first satellite.

8. The UE of claim 7.

9. When the transceiver unit receives the message from the satellite, the message further includes ninth control information, the control unit stops transmission of user data based on the ninth control information, and starts / resumes user data transmission after the UE returns from outside the satellite access range provided by the satellite to within the satellite access range. The ninth control information is information indicating that the satellite or a core network device included in the satellite requests the UE to resume transmission of user data after the UE returns from outside the satellite access range to within the satellite access range.

8. The UE of claim 7.

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