UE (user equipment)

Abstract

To clarify how to achieve storage and forward satellite operations and also clarify the detailed behavior of a UE, and / or a satellite, and / or a network.SOLUTION: A UE capable of communicating with a satellite equipped with base station functionality transmits information to the satellite indicating that it supports S&F mode, receives from the satellite information indicating that it has stored a registration request message, information indicating that a feeder link is not available, and a timer value, sets the timer value in a timer, starts the timer, and re-sends the registration request message if it receives information indicating that the registration request message could not be forwarded before the timer expires.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] In 3GPP (3rd Generation Partnership Project), the system architecture of 5GS (5G System), which is a fifth-generation (5G) mobile communication system, is being studied, and discussions are being held to support new procedures and new functions (see Non-Patent Documents 1 and 2).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Release 19, the Store and Forward (S&F) satellite operation is planned to be studied, but no disclosure is made on how to realize such operation (see Non-Patent Document 3).

[0005] One aspect of the present invention is made in view of the above circumstances, and aims to clarify a method for realizing the Store and Forward satellite operation, and to clarify the detailed behaviors of the UE, and / or the satellite, and / or the network.

Means for Solving the Problems

[0006] A UE according to one aspect of the present invention is a UE including a transceiver and a control unit, the UE being capable of communicating with a satellite equipped with a base station function, the transceiver transmitting to the satellite information indicating that the S&F mode is supported, receiving from the satellite information indicating that a registration request message has been stored, information indicating that a feeder link is not available, and a timer value, the control unit setting the timer value to a timer and starting the timer, and when the transceiver receives information indicating that the registration request message could not be transferred before the timer expires, the control unit retransmitting the registration request message.

Effects of the Invention

[0007] According to one aspect of the present invention, it is possible to clarify a method for realizing memory and transfer satellite operations, and to clarify the detailed behaviors of the UE, and / or the satellite, and / or the network.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0009] Hereinafter, with reference to the drawings, the best mode for implementing one aspect of the present invention will be described. In this embodiment, as an example, an embodiment of a mobile communication system when one aspect of the present invention is applied will be described.

[0010] [1. Outline of the System] First, FIG. 1 is a diagram for explaining the outline of the mobile communication system 1 used in each embodiment, and FIG. 2 is a diagram for explaining the detailed configuration of the mobile communication system 1.

[0011] In FIG. 1, it is described that the mobile communication system 1 is composed of UE_A10, access network_A80, core network_A90, PDN (Packet Data Network)_A5, access network_B120, core network_B190, and DN (Data Network)_A6.

[0012] Hereinafter, for these apparatuses / functions, there may be cases where symbols such as UE, access network_A, core network_A, PDN, access network_B, core network_B, DN, etc. are omitted in the description.

[0013] Also, Figure 2 shows apparatuses / functions such as UE_A10, E-UTRAN80, MME40, SGW35, PGW-U30, PGW-C32, PCRF60, HSS50, 5G AN120, AMF140, UPF130, SMF132, PCF160, UDM150, N3IWF170, etc., and interfaces connecting these apparatuses / functions to each other.

[0014] Hereinafter, for these apparatuses / functions, there may be cases where symbols such as UE, E-UTRAN, MME, SGW, PGW-U, PGW-C, PCRF, HSS, 5G AN, AMF, UPF, SMF, PCF, UDM, N3IWF, etc. are omitted in the description.

[0015] Note that the EPS (Evolved Packet System), which is a 4G system, is composed of access network_A and core network_A, but may further include UE and / or PDN. Also, the 5GS (5G System), which is a 5G system, is composed of UE, access network_B and core network_B, but may further include DN.

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

[0017] In addition, access network_A corresponds to E-UTRAN (Evolved Universal Terrestrial Radio Access Network) and / or a wireless LAN access network. One or more eNBs (evolved Node B) 45 are arranged in the E-UTRAN. Hereinafter, the eNB 45 may be described with the symbol omitted like eNB. Also, when there are a plurality of eNBs, each eNB is connected to each other, for example, by an X2 interface. In addition, one or more access points are arranged in the wireless LAN access network.

[0018] In addition, 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 NodeB) 122 are arranged in the NG-RAN. Hereinafter, the gNB 122 may be described with the symbol omitted like gNB. The gNB is a node that provides the UE with an NR (New Radio) user plane and a control plane, and is a node that connects to the 5GCN via an NG interface (including an N2 interface or an N3 interface). That is, the gNB is a base station device newly designed for 5GS and has a different function from the base station device (eNB) designed for EPS, which is a 4G system. Also, when there are a plurality of gNBs, each gNB is connected to each other, for example, by an Xn interface.

[0019] In addition, the non-3GPP access network may include an untrusted non-3GPP access network and a trusted non-3GPP access network. Here, the untrusted non-3GPP access network may be a non-3GPP access network that does not perform security management within the access network, such as a public wireless LAN. On the other hand, the trusted non-3GPP access network may be an access network defined by 3GPP and may be equipped with a TNAP (trusted non-3GPP access point) and a TNGF (trusted non-3GPP Gateway function).

[0020] In addition, hereinafter, E-UTRAN and NG-RAN may be referred to as 3GPP access. Also, a wireless LAN access network and a non-3GPP AN may be referred to as non-3GPP access. Further, the nodes arranged in access network_B may also be collectively referred to as NG-RAN nodes.

[0021] In addition, hereinafter, access network_A, access network_B, the devices included in access network_A, and the devices included in access network_B may be referred to as an access network, or an access network device, or an in-access network device.

[0022] Also, core network_A corresponds to the EPC (Evolved Packet Core). In the EPC, 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), an HSS (Home Subscriber Server), etc. are arranged.

[0023] In addition, Core Network_B is compatible with 5GCN (5G Core Network). In 5GCN, for example, AMF (Access and Mobility Management Function), UPF (User Plane Function), SMF (Session Management Function), PCF (Policy Control Function), UDM (Unified Data Management), etc. are deployed. Here, 5GCN may be expressed as 5GC.

[0024] In addition, hereinafter, Core Network_A, Core Network_B, the devices included in Core Network_A, and the devices included in Core Network_B may be referred to as the core network, or core network device, or in-core network device.

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

[0026] In addition, in FIG. 1, the case where the PDN and the DN are the same is described, but they may be different. The PDN may be a DN (Data Network) that provides communication services to the UE. Note that the DN may be configured as a packet data service network or may be configured for each service. Further, the PDN may include connected communication terminals. Therefore, connecting to the PDN may mean connecting to a communication terminal or a server device arranged in the PDN. Further, transmitting and receiving user data with the PDN may mean transmitting and receiving user data with a communication terminal or a server device arranged in the PDN. Note that the PDN may be expressed as the DN, or the DN may be expressed as the PDN.

[0027] Also, hereinafter, at least a part of the access network_A, the core network_A, the PDN, the access network_B, the core network_B, the DN, and / or one or more devices included therein may be referred to as a network (also referred to as NW) or a network device. That is, the fact that the network and / or the network device transmits and receives messages and / or executes procedures means that at least a part of the access network_A, the core network_A, the PDN, the access network_B, the core network_B, the DN, and / or one or more devices included therein transmits and receives messages and / or executes procedures.

[0028] Also, the UE can connect to the access network. Also, the UE can connect to the core network via the access network. Further, the UE can connect to the PDN or the DN via the access network and the core network. That is, the UE can transmit and receive (communicate) user data with the PDN or the DN. When transmitting and receiving user data, not only IP (Internet Protocol) communication but also non-IP communication may be used.

[0029] Here, IP communication refers to data communication using IP, and data transmission and reception are performed by IP packets. An IP packet is composed of an IP header and a payload part. The payload part may include data transmitted and received by devices / functions included in EPS and devices / functions included in 5GS. Also, non-IP communication refers to data communication without using IP, and data transmission and reception are performed in a format different from the structure of an IP packet. For example, non-IP communication may be data communication realized by transmission and reception of application data without an IP header, or may transmit and receive user data transmitted and received by a UE with another header such as a MAC header or an Ethernet (registered trademark) frame header added.

[0030] Also, access network_A, core network_A, access network_B, core network_B, PDN_A, and DN_A may be configured with devices not described in FIG. 2. For example, core network_A and / or core network_B may include an AUSF (Authentication Server Function) and an AAA (Authentication, authorization, and accounting) server (AAA-S).

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

[0032] The AAA server is a device with authentication, authorization, and charging functions that is directly or indirectly connected to the AUSF via another network device. The AAA server may be a network device within the core network. Note that the AAA server may not be included in Core Network_A and / or Core Network_B, but may be included in the PLMN. That is, 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 3rd Party.

[0033] In FIG. 2, for the sake of simplicity of the figure, each device / function is described one by one, but the mobile communication system 1 may be configured with a plurality of similar devices / functions. Specifically, the mobile communication system 1 may be configured with a plurality of devices / functions such as a plurality of UE_A10, E-UTRAN80, MME40, SGW35, PGW-U30, PGW-C32, PCRF60, HSS50, 5G AN120, AMF140, UPF130, SMF132, PCF160, and / or UDM150.

[0034] [2. Configuration of Each Device] Next, the configuration of each device (UE, and / or access network device, and / or core network device) used in each embodiment will be described with reference to the figures. Note that each device may be configured as physical hardware, or as logical (virtual) hardware configured on general-purpose hardware, or as software. Also, at least a part (including all) of the functions of each device may be configured as physical hardware, logical hardware, or software.

[0035] Furthermore, each memory unit (memory unit_A340, memory unit_B540, memory unit_B740) within each device / function that will appear below is composed of, for example, a semiconductor memory, SSD (Solid State Drive), HDD (Hard Disk Drive), etc. Also, each memory unit can store not only the information originally set at the shipping stage but also various types of information transmitted and received between devices / functions other than its own device / function (e.g., UE, and / or access network device, and / or core network device, and / or PDN, and / or DN). In addition, each memory unit can store identification information, control information, flags, parameters, etc. included in the control messages transmitted and received within various communication procedures described later. Also, each memory unit may store these information for each UE. Further, when interworking between 5GS and EPS occurs, each memory unit can store control messages and user data transmitted and received between devices / functions included in 5GS and / or EPS. At this time, not only those transmitted and received via the N26 interface but also those transmitted and received without passing through the N26 interface can be stored.

[0036] [2.1. Device Configuration of UE] First, an example of the device configuration of a UE (User Equipment) will be described with reference to FIG. 3. The UE is composed of a control unit_A300, an antenna 310, a transceiver unit_A320, and a memory unit_A340. The control unit_A300, the transceiver unit_A320, and the memory unit_A340 are connected via a bus. The transceiver unit_A320 is connected to the antenna 310.

[0037] The control unit_A300 is a functional unit that controls the operations / functions of the entire UE. The control unit_A300 realizes various processes in the UE by reading and executing various programs stored in the memory unit_A340 as necessary.

[0038] The transmission / reception unit _A320 is a functional unit for wireless communication with a base station device (eNB or gNB) in an access network via an antenna. That is, the UE can transmit and receive user data and / or control information with an access network device, and / or a core network device, and / or a PDN, and / or a DN using the transmission / reception unit _A320.

[0039] Referring to FIG. 2 for detailed description, the UE can communicate with a base station device (eNB) in the E-UTRAN via the LTE-Uu interface by using the transmission / reception unit _A320. Also, the UE can communicate with a base station device (gNB) in the 5G AN by using the transmission / reception unit _A320. Further, the UE can transmit and receive NAS (Non-Access-Stratum) messages with the AMF via the N1 interface by using the transmission / reception unit _A320. However, since the N1 interface is logical, in reality, the communication between the UE and the AMF is performed via the 5G AN.

[0040] The storage unit _A340 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the UE. Also, the storage unit _340 may have a function of storing control information transmitted and received between an access network device, a core network device, and a DN.

[0041] Also, the UE may be able to communicate with a satellite equipped with the function of a base station device.

[0042] [2.2. Device Configuration of Base Station Device] Next, an example of the device configuration of the base station device will be described with reference to FIG. 4. The base station device may be a gNB, or an eNB, or an en-gNB, or an ng-eNB. Here, the case of a gNB will be described as an example of the base station device. That is, in the following description, gNB may be read as eNB, or en-gNB, or ng-eNB. The gNB is composed of a control unit _B500, an antenna 510, a network connection unit _B520, a transceiver unit _B530, and a storage unit _B540. The control unit _B500, the network connection unit _B520, the transceiver unit _B530, and the storage unit _B540 are connected via a bus. The transceiver unit _B530 is connected to the antenna 510.

[0043] The control unit _B500 is a functional unit that controls the operations 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 storage unit _B540 as necessary.

[0044] 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 transmit and receive user data and / or control information to and from the AMF and / or UPF using the network connection unit _B520.

[0045] 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.

[0046] Referring to FIG. 2 for a detailed description, the gNB within the 5G AN can communicate with the AMF via the N2 interface and with the UPF via the N3 interface by using the network connection unit _B520. Also, the gNB can communicate with the UE by using the transceiver unit _B530.

[0047] The memory unit _B540 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the gNB. Further, the memory unit _540 may have a function of storing control information transmitted and received between the UE, other access network devices (base station devices), core network devices, and the DN.

[0048] Also, in this specification, a satellite equipped with at least the functions of a base station device may sometimes be simply referred to as a satellite or a base station device. Here, the base station device may be referred to as a base station, and may refer to a gNB, or an eNB, or an en-gNB, or an ng-eNB, or an access point accommodated in non-3GPP access (for example, something like an access point used in a wireless LAN).

[0049] [2.3. Device Configuration of AMF / MME] Next, an example of the device configuration of the AMF and the MME, which are part of the core network device or the core network function, will be described. Here, an example of the device configuration of the AMF will be described with reference to FIG. 5. Here, the case of the AMF will be described as an example, but it may be read as the MME. 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.

[0050] The control unit _B700 is a functional unit that controls the operations and functions of the entire AMF. The control unit _B700 realizes various processes in the AMF by reading out and executing various programs stored in the memory unit _B740 as necessary.

[0051] The network connection unit _B720 is a functional unit for the AMF to connect to the base station device (gNB), and / or SMF, and / or PCF, and / or UDM, and / or SCEF, and / or NSACF within the 5G AN. That is, the AMF can transmit and receive user data and / or control information to and from the base station device (gNB), and / or SMF, and / or PCF, and / or UDM, and / or SCEF within the 5G AN using the network connection unit _B720.

[0052] Referring to FIG. 2 for a detailed description, the AMF within the 5GCN can communicate with the gNB via the N2 interface, communicate with the UDM via the N8 interface, communicate with the SMF via the N11 interface, and communicate with the PCF via the N15 interface by using the network connection unit _A620. Also, the AMF can transmit and receive NAS messages to and from the UE via the N1 interface by using the network connection unit _A620. However, since the N1 interface is logical, in reality, the communication between the UE and the AMF is performed via the 5G AN. Also, when the AMF supports the N26 interface, it can communicate with the MME via the N26 interface by using the network connection unit _A620.

[0053] The storage unit _B740 is a functional unit for storing programs, user data, control information, etc. required for each operation of the AMF. Also, the storage unit _740 may have a function of storing control information transmitted and received between the UE, the access network device, other core network devices, and the DN.

[0054] Still, 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 providing integrity protection for NAS messages, performing 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 Authentication, Access Authorization) functions, security anchor functionality (SEA), security context management (SCM) functions, 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 UEs connected via the N3IWF, etc.

[0055] Also, in registration management, the RM state for each UE is managed. The RM state may be synchronized between the UE and the AMF. The RM states include an RM-DEREGISTERED state and an RM-REGISTERED state. In the RM-DEREGISTERED state, since the UE is not registered with the network, the UE context in the AMF does not have valid location information or routing information for that UE, so the AMF cannot reach the UE. Also, in the RM-REGISTERED state, since the UE is registered with the network, the UE can receive services that require registration with the network. Note that the RM state may be expressed as a 5GMM state. In this case, the RM-DEREGISTERED state may be expressed as the 5GMM-DEREGISTERED state, and the RM-REGISTERED state may be expressed as the 5GMM-REGISTERED state.

[0056] In other words, 5GMM-REGISTERED may be a state where each device has established a 5GMM context or a state where a PDU session context has been established. Note that when each device is 5GMM-REGISTERED, UE_A10 may start transmitting and receiving user data and control messages or may respond to paging. Further, note that when each device is 5GMM-REGISTERED, UE_A10 may execute a registration procedure other than the registration procedure for initial registration and / or a service request procedure.

[0057] Furthermore, 5GMM-DEREGISTERED may be a state where each device has not established a 5GMM context, a state where the network does not know the location information of UE_A10, or a state where the network cannot reach UE_A10. Note that when each device is 5GMM-DEREGISTERED, UE_A10 may start a registration procedure or may establish a 5GMM context by executing a registration procedure.

[0058] In addition, in connection management, the CM state for each UE is managed. The CM state may be synchronized between the UE and the AMF. The CM states include 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. Also, in the CM-IDLE state, the UE does not have an N2 connection and an N3 connection. On the other hand, in the CM-CONNECTED state, the UE has a NAS signaling connection established with the AMF via the N1 interface. Also, in the CM-CONNECTED state, the UE may have an N2 connection and / or an N3 connection.

[0059] 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 the idle mode, and the connected state mode may be expressed as the connected mode.

[0060] Furthermore, the CM state may also be expressed as the 5GMM mode. In this case, the non-connected state may be expressed as the 5GMM - IDLE mode, and the connected state may be expressed as the 5GMM - CONNECTED mode. Additionally, the non-connected state in 3GPP access may be expressed as the 5GMM - IDLE mode over 3GPP access, and the connected state in 3GPP access may be expressed as the 5GMM - CONNECTED mode over 3GPP access. Moreover, the non-connected state in non-3GPP access may be expressed as the 5GMM - IDLE mode over non-3GPP access, and the connected state in non-3GPP access may be expressed as the 5GMM - CONNECTED mode over non-3GPP access. Note that the 5GMM - IDLE mode may also be expressed as the idle mode, and the 5GMM - CONNECTED mode may be expressed as the connected mode.

[0061] Also, one or more AMFs may be deployed within Core Network_B. Also, the AMF may be a Network Function (NF) that manages one or more Network Slice Instances (NSIs). Also, the AMF may be a Common Control Plane Network Function (CCNF) shared among multiple NSIs.

[0062] Note that the N3IWF is a device and / or function deployed between non-3GPP access and 5GCN when the UE connects to 5GS via non-3GPP access.

[0063] [2.4. SMF / PGW Equipment Configuration] Next, an example of the device configuration of the SMF, which is a core network device or part of the core network function, will be described with reference to FIG. 5. Here, the case of the SMF will be described as an example, but it may be read as a PGW or PGW-C. The SMF is composed of a control unit _B700, a network connection unit _B720, and a storage unit _B740. The control unit _B700, the network connection unit _B720, and the storage unit _B740 are connected via a bus. The SMF may be a node that handles the control plane.

[0064] The control unit _B700 is a functional unit that controls the operations and functions of the entire SMF. The control unit _B700 realizes various processes in the SMF by reading and executing various programs stored in the storage unit _B740 as necessary.

[0065] The network connection unit _B720 is a functional unit for the SMF to connect to the AMF, and / or UPF, and / or PCF, and / or UDM. That is, the SMF can transmit and receive user data and / or control information to and from the AMF, and / or UPF, and / or PCF, and / or UDM, and / or NSACF using the network connection unit _B720.

[0066] Explaining in detail with reference to FIG. 2, the SMF within the 5GCN can communicate with the AMF via the N11 interface, communicate with the UPF via the N4 interface, communicate with the PCF via the N7 interface, and communicate with the UDM via the N10 interface by using the network connection unit _A620.

[0067] The storage unit _B740 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the SMF.

[0068] The SMF has functions such as session management (including establishment, modification, and release of PDU sessions), IP address allocation to the UE and its management function, UPF selection and control function, UPF configuration function for routing traffic to an appropriate destination (transmission target), function of sending and receiving the SM part of NAS messages, function of notifying the arrival of downlink data (Downlink Data Notification), function of providing AN-specific (per-AN) SM information transmitted to the AN via the N2 interface through the AMF, function of determining the SSC mode (Session and Service Continuity mode) for the session, roaming function, etc.

[0069] In addition, the storage unit _740 may have a function of storing control information transmitted and received between the UE, the access network device, other core network devices, and the DN.

[0070] [2.5. Device Configuration of UPF / PGW / SGW] Next, an example of the device configuration of the UPF, which is one of the core network devices or core network functions, will be described with reference to FIG. 5. Here, the case of the UPF is taken as an example for description, but it may be read as PGW or PGW-U, or SGW. The PGW may have both the functions of PGW-C and PGW-U. The UPF is composed of a control unit _B700, a network connection unit _B720, and a storage unit _B740. The control unit _B700, the network connection unit _B720, and the storage unit _B740 are connected via a bus. The UPF may be a node that handles the control plane.

[0071] The control unit _B700 is a functional unit that controls the operation and functions of the entire UPF. The control unit _B700 reads out and executes various programs stored in the storage unit _B740 as necessary to realize various processes in the UPF.

[0072] The network connection part _B720 is a functional part for the UPF to connect to the base station device (gNB) within the 5G AN, and / or the SMF, and / or the DN. That is, the UPF can use the network connection part _B720 to send and receive user data and / or control information to and from the base station device (gNB) within the 5G AN, and / or the SMF, and / or the DN.

[0073] Referring to Figure 2 for a detailed description, the UPF within the 5GCN can communicate with the gNB via the N3 interface, communicate with the SMF via the N4 interface, communicate with the DN via the N6 interface, and communicate with other UPFs via the N9 interface by using the network connection part _A620.

[0074] The storage part _B740 is a functional part for storing programs, user data, control information, etc. required for each operation of the UPF.

[0075] The UPF has functions such as a function as an anchor point for intra-RAT mobility or inter-RAT mobility, a function as an external PDU session point for interconnecting with the DN (that is, a function of transferring user data as a gateway between the DN and the core network _B), a function of routing and forwarding packets, a UL CL (Uplink Classifier) function of supporting routing of multiple traffic flows for one DN, a Branching point function of supporting multi-homed PDU sessions, a QoS (Quality of Service) processing function for the user plane, a function of verifying uplink traffic, a function of buffering downlink packets, and a function of triggering downlink data notification.

[0076] Also, the UPF may be a gateway for IP communication and / or non-IP communication. Further, the UPF may have a function of transferring IP communication, or may have a function of converting non-IP communication and IP communication. Additionally, the multiple gateways arranged may be gateways connecting the core network_B and a single DN. Note that the UPF may have connectivity with other NFs and may be connected to each device via other NFs.

[0077] Also, the storage unit_740 may have a function of storing control information transmitted and received between the UE, the access network device, other core network devices, and the DN.

[0078] [2.6. Description of Other Devices and / or Functions and Identification Information in the Present Embodiment] Next, other devices and / or functions and identification information will be described.

[0079] The network refers to at least a part of the access network_B, the core network_B, and the DN. Also, one or more devices included in at least a part of the access network_B, the core network_B, and the DN may be referred to as a network or a network device. That is, when the network executes message transmission / reception and / or processing, it may mean that a device (network device and / or control device) in the network executes message transmission / reception and / or processing. Conversely, when a device in the network executes message transmission / reception and / or processing, it may mean that the network executes message transmission / reception and / or processing.

[0080] Also, the user plane (also referred to as user plane; UP) is the user data transmitted and received between the UE and the network. Also, the UP may be a communication path for transmitting and receiving user data, or may be composed of multiple bearers. The UP may be transmitted and received using a PDN connection in the case of 4G, or a PDU session in the case of 5G. In the case of EPS, the UP 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. In the case of 5GS, the UP 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. The UP may also be expressed as the U-Plane.

[0081] Also, the control plane (also referred to as control plane; CP) is the control message transmitted and received for performing communication control of the UE. Also, the CP may be a communication path for transmitting and receiving control messages, or may be composed of multiple bearers. The CP may be transmitted and received using the NAS (Non-Access-Stratum) signaling connection between the UE and the MME. The CP may be transmitted and received using the NAS (Non-Access-Stratum) signaling connection between the UE and the AMF. In the case of EPS, the CP may be transmitted and received using the LTE-Uu interface and the S1-MME interface. In the case of 5GS, the CP may be transmitted and received using the interface between the UE and the NG RAN and the N2 interface. The CP may also be expressed as the control plane or the C-Plane.

[0082] 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.

[0083] Also, the MM (Mobility Management, also referred to as mobility management) message may be a control message transmitted and received between the UE and the AMF or MME in the MM procedure and may be a NAS message (also referred to as a NAS MM message).

[0084] Also, the MM procedure (also referred to as the procedure for MM) may include a registration procedure started by the UE, a deregistration procedure started by the UE or the AMF (or the network), a generic UE configuration update procedure started by the AMF (or the network), a service request procedure started by the UE, a paging procedure started by the AMF (or the network), and a notification procedure started by the AMF (or the network). Also, the MM procedure may include an attach procedure started by the UE, a detach procedure started by the UE or the MME (or the network), a tracking area update procedure started by the UE, a service request procedure started by the UE, and a paging procedure started by the MME (or the network).

[0085] Here, in the registration procedure, the UE may send a Registration Request message to the AMF and receive a Registration Accept message or a Registration Reject message sent by the AMF that has received this. Here, when the AMF permits the registration request from the UE, it may send a Registration Accept message, and when it does not permit it, it may send a Registration Reject message.

[0086] Also, in the deregistration procedure initiated by the UE, the UE may send a De-registration Request message to the AMF and receive a De-registration Accept message sent by the AMF that has received this.

[0087] Also, in the deregistration procedure initiated by the AMF (or the network), the AMF may send a De-registration Request message to the UE and receive a De-registration Accept message sent by the UE that has received this.

[0088] Also, in the generic UE configuration update procedure, the AMF may send a Configuration Update Command message to the UE and receive a Configuration Update Complete message sent by the UE that has received this.

[0089] Also, in the service request procedure, the UE may send a Service Request message or a Control Plane Service Request message to the AMF and receive a Service Accept message or a Service Reject message sent by the AMF that has received this. Here, when the AMF permits the request from the UE, it may send a Service Accept message, and when it does not permit it, it may send a Service Reject message.

[0090] In addition, in the paging procedure, the AMF sends a Request Paging to the base station. The base station that receives this sends a Paging message to the UE. The UE that receives this may send a service request message, or a CP service request message, or a registration request message to the AMF, and the AMF may receive this.

[0091] In addition, in the notification procedure, the AMF sends a Notification message to the UE, and may receive a Notification Response message, or a service request message, or a CP service request message, or a registration request message sent from the UE that has received this.

[0092] In addition, in the attach procedure, the UE may send an Attach Request message and receive an Attach Accept message or an Attach Reject message sent from the MME that has received this. Here, when the MME permits the request from the UE, it may send an Attach Accept message, and when it does not permit it, it may send an Attach Reject message. Also, when the UE receives an Attach Accept message, it sends an Attach Complete message, and the MME may receive this.

[0093] In addition, in the detach procedure initiated by the UE, the UE may send a Detach Request message and receive a Detach Accept message sent from the MME that has received this.

[0094] Also, in the detach procedure initiated by the MME (or the network), the MME may send a Detach Request message and receive a Detach Accept message sent from the UE that received this message.

[0095] Also, in the tracking area update procedure, the UE may send a Tracking Area Update Request message and receive a Tracking Area Update Accept message or a Tracking Area Update Reject message sent from the UE that received this message. Here, when the MME permits the request from the UE, it may send a Tracking Area Update Accept message, and when it does not permit it, it may send a Tracking Area Update Reject message. Also, when the UE receives a Tracking Area Update Accept message, it may send a Tracking Area Update Complete message, and the MME may receive this message.

[0096] Also, in the service request procedure, the UE may send a Service Request message or a Control Plane Service Request message or an Extended Service Request message to the MME and receive a Service Accept message or a Service Reject message sent from the MME that received this message. Here, when the MME permits the request from the UE, it may send a Service Accept message, and when it does not permit it, it may send a Service Reject message.

[0097] Also, in the paging procedure, the MME sends a Request Paging message to the base station. The base station that receives this message sends a Paging message to the UE. The UE that receives this message may send a service request message, or a CP service request message, or an extended service request message to the MME, and the MME may receive this message.

[0098] Also, an SM (also referred to as Session Management) message (also referred to as a NAS (Non-Access-Stratum) SM message) may be a control message transmitted and received between the UE and the SMF via the AMF in the SM procedure, and may be a NAS message (also referred to as a NAS SM message).

[0099] Also, the SM procedure (also referred to as the procedure for SM) may include a PDU session establishment procedure initiated by the UE, a PDU session modification procedure initiated by the UE or the SMF (or the network), and a UE-requested PDU session release procedure initiated by the UE or the SMF (or the network). Also, the SM procedure may include a PDN connectivity procedure initiated by the UE, a PDN disconnectivity procedure initiated by the UE, a bearer resource allocation procedure initiated by the UE, a bearer resource modification procedure initiated by the UE, a default EPS bearer context activation procedure initiated by the NW, a dedicated EPS bearer context activation procedure initiated by the NW, a dedicated EPS bearer context modification procedure initiated by the NW, and a dedicated EPS bearer context deactivation procedure initiated by the NW.

[0100] Here, in the PDU session establishment procedure, the UE may send a PDU Session Establishment Request message to the SMF and receive a PDU Session Establishment Accept message or a PDU Session Establishment Reject message sent from the SMF that has received this. Here, when the SMF permits the establishment request of the PDU session from the UE, it may send a PDU Session Establishment Accept message, or when it does not permit it, it may send a PDU Session Establishment Reject message.

[0101] Also, in the PDU session modification procedure initiated by the UE, the UE sends a PDU Sssion Modification Request message to the SMF, and the SMF that has received this may execute the PDU session modification procedure initiated by the SMF or send a PDU Session Modification Reject message to the UE, and the UE may receive this. Here, when the SMF permits the modification request of the PDU session from the UE, it may execute the PDU session modification procedure initiated by the SMF, or when it does not permit it, it may send a PDU Session Modification Reject message.

[0102] Also, in the PDU session modification procedure initiated by the SMF (or the network), the SMF sends a PDU Session Modification Command message to the UE and may receive a PDU Session Modification Complete message or a PDU Session Modification Command Reject message sent from the UE that has received this. Here, when the UE permits the modification instruction of the PDU session from the SMF, the UE may send a PDU Session Modification Complete message, and when it does not permit it, the UE may send a PDU Session Modification Command Reject message.

[0103] Also, in the PDU session release procedure initiated by the UE, the UE sends a PDU Session Release Request message to the SMF, and the SMF that has received this may execute the PDU session release procedure initiated by the SMF or send a PDU Session Release Reject message to the UE, and the UE may receive this. Here, when the SMF permits the release request of the PDU session from the UE, the SMF may execute the PDU session release procedure initiated by the SMF, and when it does not permit it, the SMF may send a PDU Session Release Reject message.

[0104] Also, in the PDU session release procedure initiated by the SMF (or the network), the SMF sends a PDU Session Release Command message to the UE and may receive a PDU Session Release Complete message sent from the UE that has received this.

[0105] Also, in the PDN connection procedure, the UE may send a PDN Connectivity Request message to the MME and receive an Activate Default EPS Bearer Context Request message or a PDN Connectivity Reject message sent from the MME that has received this. Here, when the MME permits the request from the UE, it may send an Activate Default EPS Bearer Context Request message, or when it does not permit it, it may send a PDN Connectivity Reject message.

[0106] Also, in the PDN disconnection procedure, the UE may send a PDN Disconnect Request message to the MME and receive a Deactivate EPS Bearer Context Request message or a PDN Disconnect Reject message sent from the MME that has received this. Here, when the MME permits the request from the UE, it may send a Deactivate EPS Bearer Context Request message, or when it does not permit it, it may send a PDN Disconnect Reject message.

[0107] Also, in the bearer resource allocation procedure, the UE may send a Bearer Resource Allocation Request message to the MME and receive an Activate Dedicated EPS Bearer Context Request message, a Modify EPS Bearer Context Request message, or a Bearer Resource Allocation Reject message sent from the MME that has received this. Here, when the MME permits the request from the UE, it may send an Activate Dedicated EPS Bearer Context Request message or a Modify EPS Bearer Context Request message, and when it does not permit the request, it may send a Bearer Resource Allocation Reject message.

[0108] Also, in the bearer resource modification procedure, the UE may send a Bearer Resource Modification Request message to the MME and receive an Activate Dedicated EPS Bearer Context Request message, a Modify EPS Bearer Context Request message, a Deactivate EPS Bearer Context Request message, or a Bearer Resource Modification Reject message sent from the MME that has received this. Here, when the MME permits the request from the UE, it may send an Activate Dedicated EPS Bearer Context Request message, a Modify EPS Bearer Context Request message, or a Deactivate EPS Bearer Context Request message, and when it does not permit the request, it may send a Bearer Resource Modification Reject message.

[0109] Also, in the default EPS bearer context activation procedure, the MME may send an Activate Default EPS Bearer Context Request message to the UE and receive an Activate Default EPS Bearer Context Accept message or an Activate Default EPS Bearer Context Reject message sent from the UE that has received this. Here, when the UE permits the request from the MME, it may send an Activate Default EPS Bearer Context Accept message, and when it does not permit it, it may send an Activate Default EPS Bearer Context Reject message.

[0110]

[0111] Also, in the EPS bearer context modification procedure, the MME may send a Modify EPS Bearer Context Request message to the UE and receive a Modify EPS Bearer Context Accept message or a Modify EPS Bearer Context Reject message sent from the UE that has received this. Here, when the UE permits the request from the MME, it may send a Modify EPS Bearer Context Accept message, and when it does not permit it, it may send a Modify EPS Bearer Context Reject message.

[0112] Also, in the EPS bearer context deactivation procedure, the MME may send a Deactivate EPS Bearer Context Request message to the UE and receive a Deactivate EPS Bearer Context Accept message sent from the UE that has received this.

[0113] Also, the 5GS (5G System) service may be a connection service provided using the core network_B190. Furthermore, the 5GS service may be a service different from the EPS service or a service similar to the EPS service.

[0114] Also, the non-5GS service may be a service other than the 5GS service and may include the EPS service and / or the non-EPS service.

[0115] Also, the PDN (Packet Data Network) type indicates the type of PDN connection, including Ipv4, Ipv6, Ipv4v6, and non-IP. When Ipv4 is specified, it indicates that data transmission and reception are performed using Ipv4. When Ipv6 is specified, it indicates that data transmission and reception are performed using Ipv6. When Ipv4v6 is specified, it indicates that data transmission and reception are performed using either Ipv4 or Ipv6. When non-IP is specified, it indicates that communication is performed using a communication method other than IP, rather than IP-based communication.

[0116] Also, the PDU (Protocol Data Unit) session can be defined as the association between the DN that provides the PDU connectivity service and the UE, but it can also be the connectivity established between the UE and the external gateway. The UE can use the PDU session to transmit and receive user data with the DN by establishing a PDU session via the access network_B and the core network_B in 5GS. Here, this external gateway can be a UPF, SCEF, etc. The UE can use the PDU session to execute the transmission and reception of user data with devices such as application servers located in the DN.

[0117] Also, the MA PDU session can be a PDU session that provides PDU connectivity services using 3GPP access and / or non-3GPP access.

[0118] Furthermore, each device (UE, and / or access network device, and / or core network device) may manage by associating one or more pieces of identification information with respect to a PDU session. Note that these pieces of identification information may include one or more of DNN, QoS rule, PDU session type, application identification information, NSI identification information, and access network identification information, and may further include other information. Furthermore, when establishing a plurality of PDU sessions, each piece of identification information associated with a PDU session may have the same content or different content.

[0119] Also, a 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_A30 / UPF_A235 for connecting to a core network B190. Furthermore, the DNN may correspond to an APN (Access Point Name).

[0120] Also, a PDU (Protocol Data Unit / Packet Data Unit) session type indicates the type of a PDU session, and includes Ipv4, Ipv6, Ethernet, and Unstructured. When Ipv4 is specified, it indicates that data transmission and reception are performed using Ipv4. When Ipv6 is specified, it indicates that data transmission and reception are performed using Ipv6. When Ethernet is specified, it indicates that Ethernet frame transmission and reception are performed. Also, Ethernet may indicate that communication using IP is not performed. When Unstructured is specified, it indicates that data is transmitted and received to / from an application server or the like in a DN using Point-to-Point (P2P) tunneling technology. As the P2P tunneling technology, for example, UDP / IP encapsulation technology may be used. Note that the PDU session type may include IP in addition to the above. IP can be specified when a UE can use both Ipv4 and Ipv6.

[0121] Also, the PDN connection can be defined as the association between the PDN represented by the APN and the UE, or it can be the connectivity established between the UE and the external gateway. In EPS, the UE can use the PDN connection to send and receive user data with the PDN by establishing a PDN connection via the access network_A and the core network_A. Here, this external gateway can be a PGW, an SCEF, etc. The UE can use the PDN connection to execute the sending and receiving of user data with devices such as the application server located in the PDN.

[0122] Also, a PLMN (Public land mobile network) is a communication network that provides mobile radio communication services. The PLMN is a network managed by an operator who is a communication service provider, and the operator can be identified by the PLMN ID. The PLMN that matches the MCC (Mobile Country Code) and MNC (Mobile Network Code) of the UE's IMSI (International Mobile Subscriber Identity) can be the Home PLMN (HPLMN). Furthermore, the UE may hold an Equivalent HPLMN list for identifying one or more EPLMNs (Equivalent HPLMN) in the USIM. A PLMN different from the HPLMN and / or the EPLMN can be a VPLMN (Visited PLMN). The PLMN in which the UE has successfully registered can be an RPLMN (Registered PLMN; also referred to as the registered PLMN). Note that the service provided by the PLMN can be read as the PLMN service, and the service provided by the SNPN can be read as the SNPN service.

[0123] The tracking area is one or more ranges that can be represented by the location information of UE_A10 and are managed by the core network. The tracking area may be composed of multiple cells. Furthermore, the tracking area may be the range in which control messages such as paging are broadcast, or may be the range in which UE_A10 can move without performing a handover procedure. Furthermore, the tracking area (also referred to as Tracking Area, TA) may be a routing area, a location area, or anything similar. The tracking area may be identified by TAI (Tracking Area Identity) composed of TAC (Tracking area code) and PLMN.

[0124] The registration area (also referred to as Registration area or registration area) is a set of one or more TAs assigned by the AMF to the UE. Note that UE_A10 may be able to move without transmitting or receiving signals for tracking area update while moving within one or more TAs included in the registration area. In other words, the registration area may be a group of information indicating an area where UE_A10 can move without performing a tracking area update procedure. The registration area may be identified by a TAI list composed of one or more TAIs.

[0125] The UE ID is information for identifying the UE. Specifically, for example, the UE ID may be an SUCI (Subscription Concealed Identifier), or an SUPI (Subscription Permanent Identifier), or a GUTI (Globally Unique Temporary Identifier), or an IMEI (International Mobile Subscriber Identity), or an IMEISV (IMEI Software Version), or a TMSI (Temporary Mobile Subscriber Identity). Alternatively, the UE ID may be other information set within the application or network. Furthermore, the UE ID may be information for identifying the user.

[0126] Also, a UE in single registration mode has only one active MM state. That is, a UE in single registration mode is active only in either the RM state (5GMM state) in the 5GC or the EMM state in the EPC. Also, when a UE in single registration mode connects to the 5GC, it is in the 5GC NAS mode, and when it connects to the EPC, it is in the EPC NAS mode. Also, since a UE in single registration mode can be registered only with either the 5GC or the EPC, it is necessary to map the EPS-GUTI (also referred to as 4G-GUTI) and the 5G-GUTI during handover between the EPC and the 5GC.

[0127] Also, a UE in dual registration mode may be in a state where it can register independently with respect to the 5GC and the EPC. A UE in dual registration mode can maintain the 5G-GUTI and the EPS-GUTI (also referred to as 4G-GUTI) independently.

[0128] Also, the Store and Forward (also referred to as S&F) satellite operation (also referred to as the Store and Forward satellite operation mode) means that a serving satellite provides communication services to a UE in a period and / or geographical area without simultaneously connecting to a terrestrial network via a feeder link or an Inter-Satellite Link (ISL). In the case of the uplink (also referred to as UL), store may mean storing UL information from the UE in the satellite, and forward may mean forwarding the stored UL information to the terrestrial network. Also, in the case of the downlink (also referred to as DL), store may mean storing DL information from the terrestrial network in the satellite, and forward may mean forwarding the stored UL information to the UE. Also, the S&F satellite operation mode may be a mode in which there is no connectivity either in the service link, which is the connectivity between the UE and the satellite, or in the feeder link, which is the connectivity between the satellite and the network. Note that in this specification, the Store and Forward satellite operation may sometimes be referred to as S&F, the S&F function, or the S&F mode.

[0129] Also, normal satellite operation (also referred to as normal satellite operation mode) may be an operation mode different from the S&F satellite operation mode. Also, normal satellite operation may be a mode in which there is service link connectivity and feeder link connectivity. Also, normal satellite operation may be a mode in which the above-described storing (store) and forwarding (forward) are not performed. Also, normal satellite operation may be an operation mode in which the satellites in orbit provide communication services to the UE in a period and / or geographical area such that the satellites in orbit are simultaneously connected to the terrestrial network via the feeder link or the inter-satellite link. Also, normal satellite operation may be referred to as default satellite operation (also referred to as default satellite operation mode). Note that in this specification, normal satellite operation may be referred to as the normal mode or the normal operation mode.

[0130] Also, a serving satellite may be a satellite that provides satellite connection to the UE (for example, provides a serving cell). Depending on the orbit, the serving satellite may cover a certain geographical area for a limited period. In other words, a UE with a serving satellite may be able to communicate via the satellite, while a UE without a serving satellite may not be able to communicate via the satellite. Also, a serving satellite operating in the S&F mode may be in a state without feeder link connectivity.

[0131] Also, UE satellite-UE communication (also referred to as UE-Satellite-UE Communication) may mean communication between UEs within the range of one or more serving satellites. Also, UE satellite-UE communication may mean communication between UEs that utilizes a satellite connection such that user traffic (also referred to as user data) does not pass through the terrestrial segment (e.g., including the core network).

[0132] Furthermore, the UE, and / or the base station, and / or the NW (e.g., MME, or SGW, or PGW, or AMF, or SMF, or UPF, etc., the same hereinafter) may store information in advance and generate new information as needed. Also, when such information is transmitted and received between them, the receiving side may store the received information and act based on that information.

[0133] Also, the UE, and / or the satellite, and / or the NW may operate in the S&F mode or may operate in the normal mode.

[0134] Also, the case of operating in the S&F mode and the case of operating in the normal mode may be only the UE, or only the satellite, or only the NW. For example, when only the satellite operates in the S&F mode and in the normal mode, entities other than the satellite (in this case, the UE and the NW) do not operate in either the S&F mode or the normal mode and may act according to the mode in which the satellite operates. Also, when only the UE operates in the S&F mode and in the normal mode, entities other than the UE (in this case, the satellite and the NW) do not operate in either the S&F mode or the normal mode and may act according to the mode in which the UE operates. Also, when only the NW operates in the S&F mode and in the normal mode, entities other than the NW (in this case, the UE and the satellite) do not operate in either the S&F mode or the normal mode and may act according to the mode in which the NW operates.

[0135] Also, for the sake of simplicity, the case where the UE, and / or the satellite, and / or the NW operates in the S&F mode is expressed in a simplified manner, such as the case of operating in the S&F mode (when not operating in the standard mode). Also, for the sake of simplicity, the case where the UE, and / or the satellite, and / or the NW operates in the normal mode is expressed in a simplified manner, such as the case of operating in the normal mode (when not operating in the S&F mode).

[0136] Also, the UE, and / or the satellite, and / or the NW may operate by switching between the S&F mode and the normal mode. For example, when the UE, and / or the satellite, and / or the NW is operating in the normal mode, a certain procedure may be started, and during the execution of the procedure, it may switch from the normal mode to the S&F mode. Also, when the UE, and / or the satellite, and / or the NW is operating in the S&F mode, a certain procedure may be started, and during the execution of the procedure, it may switch from the S&F mode to the normal mode.

[0137] [3. First Embodiment] First, regarding the transmission of an MM message or an SM message (also referred to as a first control message) or user data (also referred to as Mobile originated (MO) data, uplink data) in an MM procedure or an SM procedure started by the UE, the behavior of the UE, the satellite, and the NW (for example, MME, or SGW, or PGW, or AMF, or SMF, or UPF, etc., the same hereinafter) will be described.

[0138] The UE, and / or the satellite, and / or the NW may perform behavior based on the information it grasps and / or the information transmitted and received.

[0139] In this embodiment, unless otherwise noted, the UE, and / or the satellite, and / or the NW is assumed to support the S&F function or the S&F mode and will be described.

[0140] Also, the UE may be able to communicate with a satellite equipped with the functions of a base station device.

[0141] In addition, the UE may send information indicating whether it supports the S&F function or the S&F mode to the satellite and / or the NW. The UE may include this information in NAS messages and / or control information and / or control messages of layers lower than the NAS layer (e.g., the physical layer, MAC layer, RLC layer, PDCP layer, RRC layer). For example, the control message of the RRC layer may be RRC signaling (also referred to as an RRC message), or the control information of the RRC layer may be system information. Also, the NAS message may be, for example, an MM message and / or an SM message. When the UE supports the S&F function or the S&F mode, the UE may send information indicating that it supports the S&F function or the S&F mode to the satellite and / or the NW. By receiving this control information, the satellite and / or the NW may recognize and store whether the UE supports the S&F function or the S&F mode.

[0142] In addition, the satellite may include information indicating whether it supports the S&F function or the S&F mode in NAS messages and / or control information and / or control messages of layers lower than the NAS layer, and send it to the UE and / or the NW. For example, the control message of the RRC layer may be RRC signaling (also referred to as an RRC message), or the control information of the RRC layer may be system information. Also, the NAS message may be, for example, an MM message and / or an SM message. When the satellite supports the S&F function or the S&F mode, the satellite may send information indicating that it supports the S&F function or the S&F mode to the UE and / or the NW. By receiving this control information, the UE and / or the NW may recognize and store whether the satellite supports the S&F function or the S&F mode.

[0143] Further, the NW may include information indicating whether it supports the S&F function or the S&F mode in the control information and / or control messages of the NAS layer and transmit it to the UE and / or the satellite. For example, the control message of the NAS layer may be an MM message and / or an SM message. When the NW supports the S&F function or the S&F mode, the NW may transmit information indicating that it supports the S&F function or the S&F mode to the UE and / or the satellite. By receiving this control information, the UE and / or the satellite may recognize and store whether the NW supports the S&F function or the S&F mode.

[0144] In addition, the satellite may include information indicating whether it is operating in the S&F mode, and / or information indicating whether the service link is available, and / or information indicating whether the feeder link is available, and / or information indicating whether it is operating in the normal mode, and / or information indicating the time and / or period for applying the S&F mode (canceling the application of the normal mode), and / or information indicating the time and / or period for canceling the application of the S&F mode (applying the normal mode) in the NAS message and / or the control information and / or control message of a lower layer than the NAS layer (e.g., physical layer, MAC layer, RLC layer, PDCP layer, RRC layer), and transmit it to the UE and / or NW. For example, the control message of the RRC layer may be an RRC message, and the control information of the RRC layer may be system information. Also, the NAS message may be, for example, an MM message and / or an SM message. Also, these information may be transmitted periodically or each time an event occurs. Here, the event may be, for example, when the mode is changed (when it becomes the S&F mode or the normal mode), when the state of the service link is changed (when the service link becomes available or unavailable), when the state of the feeder link is changed (when the feeder link becomes available or unavailable), etc. Here, the satellite may determine whether to transmit at least a part of these information to the UE based on the information indicating whether it supports the S&F function or the S&F mode received from the UE and / or NW. For example, when receiving information indicating that the UE and / or NW supports the S&F function or the S&F mode, the satellite determines whether to transmit at least a part of these information to the UE. If it is determined to transmit, it may transmit to the UE and / or NW, and if it is determined not to transmit, it does not have to transmit to the UE and / or NW. Also, when at least a part of these information has not yet been transmitted to the UE and / or NW, or when at least a part of these information has been updated, it may be determined to transmit to the UE and / or NW.Also, if at least a part of this information has already been transmitted to the UE and / or NW, or if the transmitted information has not been updated, it may be determined not to transmit it to the UE and / or NW.

[0145] Also, the information indicating whether it is operating in the S&F mode may be read as the information indicating that it is operating in the S&F mode or the information indicating that it is not operating in the S&F mode. Also, the information indicating whether the service link is available (also referred to as whether the service link has connectivity) may be read as the information indicating that the service link is available (also referred to as that the service link has connectivity) or the information indicating that the service link is not available (also referred to as that the service link has no connectivity). Also, the information indicating whether the feeder link is available (also referred to as whether the feeder link has connectivity) may be read as the information indicating that the feeder link is available (also referred to as that the feeder link has connectivity) or the information indicating that the feeder link is not available (also referred to as that the feeder link has no connectivity). Also, the information indicating whether it is operating in the normal mode may be read as the information indicating that it is operating in the normal mode or the information indicating that it is not operating in the normal mode.

[0146] For example, when the satellite is operating in the S&F mode, it may transmit to the UE and / or NW the information indicating that it is operating in the S&F mode and / or the information indicating that it is not operating in the normal mode. The UE and / or NW may recognize and store that it is operating in the S&F mode and / or that it is not operating in the normal mode by receiving at least one of these control information.

[0147] Also, when the satellite is operating in the normal mode, it may transmit information indicating that it is operating in the normal mode and / or information indicating that it is not operating in the S&F mode to the UE and / or the NW. The UE and / or the NW may recognize and store the fact that it is not operating in the S&F mode and / or that it is operating in the normal mode by receiving at least one of these control information.

[0148] Also, when the satellite is operating in the S&F mode, the service link is available, and the feeder link is not available, it may transmit information indicating that it is operating in the S&F mode, and / or information indicating that it is not operating in the normal mode, and / or information indicating that the service link is available, and / or information indicating that the feeder link is not available to the UE. The UE and / or the NW may recognize and store the fact that it is operating in the S&F mode, and / or that it is not operating in the normal mode, and / or that the service link is available, and / or that the feeder link is not available by receiving at least one of these control information.

[0149] Also, when the satellite is operating in the S&F mode, the service link is not available, and the feeder link is available, it may transmit information indicating that it is operating in the S&F mode, and / or information indicating that it is not operating in the normal mode, and / or information indicating that the service link is not available, and / or information indicating that the feeder link is available to the NW. The UE and / or the NW may recognize and store the fact that it is operating in the S&F mode, and / or that it is not operating in the normal mode, and / or that the service link is not available, and / or that the feeder link is available by receiving at least one of these control information.

[0150] Also, when the satellite is operating in the normal mode, it may transmit to the UE and / or NW information indicating that it is operating in the normal mode, and / or information indicating that it is not operating in the S&F mode, and / or information indicating that the service link is available, and / or information indicating that the feeder link is available. The UE and / or NW may recognize and store that it is not operating in the S&F mode, and / or that it is operating in the normal mode, and / or that the service link is available, and / or that the feeder link is available by receiving at least one of these control information.

[0151] Further, the satellite may transmit to the UE and / or NW information indicating the time and / or period when the S&F mode is to be applied (the application of the normal mode is to be cancelled), and / or information indicating the time and / or period when the application of the S&F mode is to be cancelled (the normal mode is to be applied).

[0152] For example, when a satellite operating in the normal mode intends to operate in the S&F mode, it may transmit information indicating the time and / or period when the S&F mode is to be applied (the application of the normal mode is to be cancelled). The UE and / or NW may recognize and store the application of the S&F mode, and / or the cancellation of the application of the normal mode, and / or the time and / or period when the S&F mode is to be applied by receiving at least one of these control information.

[0153] Also, when a satellite operating in the S&F mode intends to operate in the normal mode, it may transmit information indicating the time and / or period when the application of the S&F mode is to be cancelled (the normal mode is to be applied). The UE and / or NW may recognize and store the cancellation of the application of the S&F mode, and / or the application of the normal mode, and / or the time and / or period when the normal mode is to be applied by receiving at least one of these control information.

[0154] Also, when a UE and / or NW operating in the normal mode does not receive information indicating operation in the S&F mode and / or information indicating non-operation in the normal mode, it may recognize and remember that it is operating in the normal mode.

[0155] Also, when a UE and / or NW operating in the S&F mode does not receive information indicating non-operation in the S&F mode and / or information indicating operation in the normal mode, it may recognize and remember that it is operating in the S&F mode.

[0156] Also, when a UE and / or NW operating in the normal mode does not receive information indicating that the service link is unavailable or information indicating that the feeder link is unavailable, it may be recognized and remembered as operating in the normal mode and may behave in the normal mode.

[0157] Also, when a UE and / or NW operating in the S&F mode does not receive information indicating that the service link is available and information indicating that the feeder link is available, it may be recognized and remembered as operating in the S&F mode and may behave in the S&F mode.

[0158] Also, when operating in the normal mode, the UE, and / or satellite, and / or NW may transmit and receive control messages (e.g., MM messages and / or SM messages) and user data.

[0159] In addition, information indicating whether it is operating in the S&F mode, and / or information indicating whether a service link is available, and / or information indicating whether a feeder link is available, and / or information indicating whether it is operating in the normal mode, and / or information indicating the time and / or period when the S&F mode is applied, and / or information indicating the time and / or period when the application of the S&F mode is cancelled may be included in and transmitted / received in the following control messages 1 to 8, or may be included in and transmitted / received in a control message different from the following control messages 1 to 8. For example, before transmitting / receiving the first control message, it may be included in and transmitted / received in a control message different from the following control messages 1 to 8. Also, for example, after transmitting / receiving the first control message and before transmitting / receiving the eighth control message, it may be included in and transmitted / received in a control message different from the following control messages 1 to 8. Also, for example, after transmitting / receiving the eighth control message, it may be included in and transmitted / received in a control message different from the following control messages 1 to 8.

[0160] In addition, when the UE is operating in the S&F mode (when the service link is not available but the feeder link is available), the UE does not have to transmit an MM message or an SM message (also referred to as the first control message) or user data (also referred to as Mobile originated (MO) data, uplink data) in the MM procedure or the SM procedure started by the UE to the NW via the satellite.

[0161] In addition, when the UE is operating in the S&F mode (when the service link is available but the feeder link is not available), the UE does not have to transmit the first control message or user data to the NW via the satellite.

[0162] Also, when the UE is operating in the S&F mode (when the service link is available but the feeder link is not available) or when it is operating in the normal mode, the UE may transmit the first control message or user data to the NW via the satellite. Note that the UE may start a timer (also referred to as the first timer) based on the transmission of the first control message or user data.

[0163] Also, when the UE transmits the first control message or user data to the NW via the satellite when it is operating in the S&F mode (when the service link is available but the feeder link is not available), the satellite may transmit a control message (also referred to as the second control message) including information indicating that it could not transfer the first control message or user data as a response to the received first control message or user data, and / or information indicating that the first control message or user data could not be transferred because the feeder link is not available, etc., to the UE. The second control message may be, for example, a control message of a layer lower than the NAS layer (e.g., physical layer, MAC layer, RLC layer, PDCP layer, RRC layer), or may be a control message (NAS message) of the NAS layer. Also, based on the reception of the second control message and / or the control information included in the second control message, the UE may recognize that the MM procedure or SM procedure started by the UE has been rejected, may stop the second timer operating in the UE, may recognize that the first control message or user data has not been transferred to the NW, may retransmit the first control message or user data immediately or after waiting for a predetermined period (also referred to as the second predetermined period), may execute retransmission of the same procedure or user data after waiting for the second predetermined period, may execute retransmission of the same procedure or user data when switching to the normal mode operation, or may execute retransmission of the same procedure or user data when operating in the S&F mode but the feeder link becomes available.

[0164] Also, when the UE is operating in the S&F mode (when the service link is available but the feeder link is not available), if the UE transmits the first control message or user data to the NW via the satellite, the satellite may store the received first control message or user data for a predetermined period (also referred to as the first predetermined period). In this case, the satellite may transmit a control message (also referred to as the third control message) to the UE, including information indicating that the feeder link is not available, and / or information indicating that the first control message or user data has been stored, and / or information indicating that the first control message or user data has been stored because the feeder link is not available, and / or the first predetermined period (i.e., the storage period), etc. The third control message may be, for example, a control message of a layer lower than the NAS layer (e.g., physical layer, MAC layer, RLC layer, PDCP layer, RRC layer), or it may be a NAS message. Note that the first predetermined period may be included in the third control message as a timer value. Also, based on the reception of the third control message and / or the control information included in the third control message, the UE may recognize information indicating that the feeder link is not available, and / or information indicating that the first control message or user data has been stored, and / or information indicating that the first control message or user data has been stored because the feeder link is not available, and / or the first predetermined period, etc. Further, the first predetermined period may be a period predetermined by the standard, or it may be a period dependent on the implementation of the satellite. Additionally, based on the reception of the third control message and / or the control information included in the third control message, the UE may start a timer (also referred to as the second timer). At this time, the UE may start the second timer using the first predetermined period (or timer value) received from the satellite. Also, based on the transmission of the third control message and / or the control information included in the third control message, and / or the storage of the first control message or user data, the satellite may start a timer (also referred to as the third timer).At this time, the satellite may start a third timer using the first predetermined period (or timer value) transmitted to the UE. Additionally, the third control message and / or at least one piece of control information included in the third control message may be referred to as store indication or AS (Access Stratum) indication.

[0165] Furthermore, within the first predetermined period, when the feeder link becomes unavailable, the satellite may discard or delete the first control message and / or the control information included in the first control message, or the user data received from and stored by the UE, and may transmit a second control message to the UE as a response to the received first control message or user data. Additionally, the satellite may manage the first predetermined period using a timer (the third timer). That is, "when the feeder link becomes unavailable within the first predetermined period" may be read as "when the feeder link becomes unavailable between the start of the third timer using the first predetermined period and the expiration of the third timer". Also, when the UE receives the second control message and / or the control information included in the second control message before the expiration of the second timer, the UE may recognize that the MM procedure or SM procedure it started has been rejected, may stop the second timer operating in the UE, may recognize that the first control message or user data has not been transferred to the NW, may retransmit the first control message or user data immediately or after waiting for a predetermined period (also referred to as the second predetermined period), may execute the retransmission of the same procedure or user data after waiting for the second predetermined period, may execute the retransmission of the same procedure or user data when switching to the normal mode of operation, or may execute the retransmission of the same procedure or user data when operating in the S&F mode but the feeder link has become available.

[0166] Also, when the feeder link becomes available within a first predetermined period, the satellite may transmit (i.e., forward) to the NW the first control message received from and stored by the UE, and / or the control information included in the first control message, or user data. In this case, the satellite may transmit to the UE a control message (also referred to as the fourth control message) including information indicating that the first control message or user data has been forwarded due to the availability of the feeder link, or information indicating that the stored first control message or user data has been forwarded. The fourth control message may be, for example, a control message of a layer lower than the NAS layer (e.g., physical layer, MAC layer, RLC layer, PDCP layer, RRC layer), or may be a NAS message. Note that the satellite may manage the first predetermined period using a timer (the third timer). That is, "when the feeder link becomes available within a first predetermined period" may be read as "when the feeder link becomes available after starting the third timer using the first predetermined period and before the third timer expires". Note that the fourth control message, or at least one piece of control information included in the fourth control message, may be referred to as a forward indication or an AS (Access Stratum) indication. Also, based on the reception of the fourth control message and / or the control information included in the fourth control message, the UE may stop the second timer operating in the UE, may recognize that the first control message or user data has been forwarded to the NW, or may recognize that it is not necessary to retransmit the first control message or user data. Also, based on the transmission of the fourth control message and / or the control information included in the fourth control message, the satellite may stop the third timer operating in the satellite. Note that when the feeder link becomes available may mean when switching to the operation in the normal mode, or when operating in the S&F mode but the feeder link becomes available.

[0167] Also, if the UE does not receive a fourth control message from the satellite before the second timer in operation expires, the UE may recognize that the MM procedure or SM procedure it initiated has been rejected, may stop the second timer that was operating, may recognize that the first control message or user data has not been transferred to the NW, may retransmit the first control message or user data immediately or after waiting for a second predetermined period, may execute retransmission of the same procedure or user data after waiting for the second predetermined period, may execute retransmission of the same procedure or user data when switching to operation in the normal mode, or may execute retransmission of the same procedure or user data when operating in the S&F mode but the feeder link becomes available.

[0168] In addition, when starting the second timer, the UE may suspend the first timer in operation. Also, when the UE stops the second timer or when the second timer expires, the UE may resume the count of the suspended first timer.

[0169] Also, the NW may receive from the satellite the first control message or user data in the MM procedure or SM procedure initiated by the UE.

[0170] In addition, in the MM procedure or SM procedure initiated by the UE, when the NW is operating in the S&F mode (the service link is available but the feeder link is not available) after receiving the first control message from the satellite, the NW does not have to transmit, via the satellite, an MM message or an SM message (also referred to as the fifth control message) to the UE as a response to the first control message.

[0171] In addition, when the NW is operating in the S&F mode after receiving the first control message from the satellite in the MM procedure or SM procedure initiated by the UE (when the service link is not available but the feeder link is available), it may not transmit the fifth control message to the UE via the satellite as a response to the first control message.

[0172] In addition, when the NW is operating in the S&F mode after receiving the first control message from the satellite in the MM procedure or SM procedure initiated by the UE (when the service link is not available but the feeder link is available), or when the NW is operating in the normal mode, it may transmit the fifth control message to the UE via the satellite as a response to the first control message.

[0173] In addition, when the NW transmits the fifth control message to the UE via the satellite when operating in the S&F mode (when the service link is not available but the feeder link is available), the satellite may transmit a control message (also referred to as the sixth control message) including information indicating that it could not forward the fifth control message as a response to the received fifth control message, and / or information indicating that the fifth control message could not be forwarded because the service link is not available, etc. to the NW. The sixth control message may be, for example, a control message (NAS message) at the NAS layer. In addition, based on the reception of the sixth control message and / or the control information included in the sixth control message, the NW may recognize that the MM procedure or SM procedure initiated by the UE has been rejected, may stop the fourth timer operating in the NW, may recognize that the fifth control message has not been transferred to the UE, may retransmit the fifth control message immediately or after waiting for a predetermined period (also referred to as the fourth predetermined period), may retransmit the fifth control message when switching to the normal mode of operation, or may retransmit the fifth control message when the service link becomes available while operating in the S&F mode.

[0174] Also, when the NW is operating in the S&F mode (when the service link is not available but the feeder link is available), if the NW transmits a fifth control message to the UE via the satellite, the satellite may store the received fifth control message for a predetermined period (also referred to as the third predetermined period). In this case, the satellite may transmit a control message (also referred to as the seventh control message) to the NW, which includes information indicating that the service link is not available, and / or information indicating that the fifth control message has been stored, and / or information indicating that the fifth control message has been stored because the service link is not available, and / or the third predetermined period (i.e., the storage period), etc. The seventh control message may be, for example, a NAS message. Note that the third predetermined period may be included in the seventh control message as a timer value. Also, based on the reception of the seventh control message and / or the control information included in the seventh control message, the NW may recognize information indicating that the service link is not available, and / or information indicating that the seventh control message has been stored, and / or information indicating that the seventh control message has been stored because the service link is not available, and / or the third predetermined period, etc. Also, the third predetermined period may be a period predetermined in the standard or a period depending on the implementation of the satellite. Further, based on the reception of the seventh control message and / or the control information included in the seventh control message, the NW may start a timer (also referred to as the fourth timer). At this time, the NW may start the fourth timer using the third predetermined period (or timer value) received from the satellite. Also, based on the transmission of the seventh control message and / or the control information included in the seventh control message, and / or the storage of the fifth control message, the satellite may start a timer (also referred to as the fifth timer). At this time, the satellite may start the fifth timer using the third predetermined period (or timer value) transmitted to the NW. Note that the seventh control message and / or at least one piece of control information included in the seventh control message may be referred to as a store indication or an AS (Access Stratum) indication.

[0175] Furthermore, when the service link becomes unavailable within a third predetermined period, the satellite discards or deletes the fifth control message received from and stored in the NW, and / or the control information included in the fifth control message, and may also transmit a sixth control message to the NW as a response to the received fifth control message. Note that the satellite may manage the third predetermined period using a timer (the fifth timer). That is, "when the service link becomes unavailable within a third predetermined period" may be construed as "when the service link does not become available between the start of the fifth timer using the third predetermined period and the expiration of the fifth timer". Also, based on the reception of the sixth control message and / or the control information included in the sixth control message, the NW may recognize that the MM procedure or the SM procedure started by the UE has been rejected, may stop the fourth timer operating in the NW, may recognize that the fifth control message has not been transferred to the UE, may retransmit the fifth control message immediately or after waiting for a predetermined period (also referred to as the fourth predetermined period), may retransmit the fifth control message when switching to the normal mode of operation, or may retransmit the fifth control message when operating in the S&F mode but the service link has become available.

[0176] Also, when the service link becomes available within a third predetermined period, the satellite may transmit (i.e., forward) to the UE the fifth control message received from the NW and stored therein, and / or the control information included in the fifth control message. In this case, the satellite may transmit to the NW a control message (also referred to as the eighth control message) including information indicating that the fifth control message has been forwarded because the service link has become available, or information indicating that the stored fifth control message has been forwarded. The eighth control message may be, for example, a NAS message. Note that the satellite may manage the third predetermined period using a timer (the fifth timer). That is, "when the service link becomes available within a third predetermined period" may be read as "when the service link becomes available after starting the fifth timer using the third predetermined period and before the fifth timer expires". Note that the eighth control message, or at least one control information included in the eighth control message, may be referred to as a forward indication or an AS (Access Stratum) indication. Further, based on the reception of the eighth control message and / or the control information included in the eighth control message, the NW may stop the fourth timer operating in the NW, may recognize that the fifth control message has been forwarded to the UE, or may recognize that it is not necessary to retransmit the fifth control message. Also, the satellite may stop the fifth timer operating in the satellite based on the transmission of the eighth control message and / or the control information included in the eighth control message. Note that when the service link becomes available may mean when switching to the operation in the normal mode, or when operating in the S&F mode but the service link becomes available.

[0177] Also, if the NW does not receive the eighth control message from the satellite before the fourth timer in operation expires, the NW may recognize that the MM procedure or SM procedure initiated by the UE has been rejected, or may stop the fourth timer operating in the NW, or may recognize that the fifth control message has not been transferred to the UE, or may retransmit the fifth control message immediately or after waiting for only a fourth predetermined period, or may retransmit the fifth control message when switching to operation in the normal mode, or may retransmit the fifth control message when operating in the S&F mode but the service link becomes available.

[0178] Also, if the UE receives the fifth control message from the NW via the satellite before the first timer in operation expires, the UE may recognize that the MM procedure or SM procedure initiated by the UE has ended normally.

[0179] Also, if the UE does not receive the fifth control message from the NW via the satellite before the first timer in operation expires, the UE may recognize that the MM procedure or SM procedure initiated by the UE has ended normally.

[0180] Note that the first control message may be a registration request message, and the fifth control message may be a registration acceptance message or a registration rejection message. In this case, the first timer may be the T3510 timer.

[0181] Also, the first control message may be a deregistration request message, and the fifth control message may be a deregistration acceptance message. In this case, the first timer may be the T3521 timer.

[0182] Also, the first control message may be a deregistration request message, and the fifth control message may not exist. In this case, the first timer may not exist.

[0183] Also, the first control message may be a service request message or a CP service request message, and the fifth control message may be a service acceptance message or a service rejection message. In this case, the first timer may be the T3517 timer.

[0184] Also, the first control message may be an uplink (UL) NAS transport message, and the fifth control message may not exist. In this case, the first timer may not exist.

[0185] Also, the first control message may be a PDU session establishment request message, and the fifth control message may be a PDU session establishment acceptance message or a PDU session establishment rejection message. In this case, the first timer may be the T3580 timer.

[0186] Also, the first control message may be a PDU session modification request message, and the fifth control message may be a PDU session modification command message or a PDU session modification rejection message. In this case, the first timer may be the T3581 timer.

[0187] Also, the first control message may be a PDU session release request message, and the fifth control message may be a PDU session release command message or a PDU session release rejection message. In this case, the first timer may be the T3582 timer.

[0188] Also, the first control message may be an attach request message, and the fifth control message may be an attach acceptance message or an attach rejection message. In this case, the first timer may be T3410.

[0189] Also, the first control message may be a detach request message, and the fifth control message may not exist. In this case, the first timer may not exist.

[0190] Also, the first control message may be a detach request message, and the fifth control message may be a detach acceptance message. In this case, the first timer may be T3421.

[0191] Also, the first control message may be a tracking area update request message, and the fifth control message may be a tracking area update acceptance message or a tracking area update rejection message. In this case, the first timer may be T3430.

[0192] Also, the first control message may be a service request message or a CP service request message or an extended service request message, and the fifth control message may be a service acceptance message or a service rejection message. In this case, the first timer may be T3417.

[0193] Also, the first control message may be a PDN connectivity request message, and the fifth control message may be an activate default EPS bearer context request message or a PDN connectivity rejection message. In this case, the first timer may be T3482.

[0194] Also, the first control message may be a PDN disconnection request message, and the fifth control message may be a deactivate EPS bearer context request message or a PDN disconnection rejection message. In this case, the first timer may be T3492.

[0195] Also, the first control message may be a bearer resource allocation request message, and the fifth control message may be an activate dedicated EPS bearer context request message or a modify EPS bearer context request message or a bearer resource allocation rejection message. In this case, the first timer may be T3480.

[0196] Also, the first control message is a bearer resource modification request message, and the fifth control message may be an activate dedicated EPS bearer context request message, a modified EPS bearer context request message, a deactivate EPS bearer context request message, or a bearer resource modification rejection message. In this case, the first timer may be T3481.

[0197] Also, when the UE receives the second control message from the satellite, instead of starting the second timer, it may extend the operating first timer. For example, the UE may extend the first timer indefinitely until it receives the fifth control message, or extend it for a certain period.

[0198] Also, the first to eighth control messages may include user data in addition to control information.

[0199] Also, the behaviors of the above UE, satellite, and NW operating in the S&F mode can also be applied before or during the execution of the above procedure or the transmission of user data, when attempting to operate in the normal mode, or when switching to the normal mode.

[0200] Also, the behaviors of the above UE, satellite, and NW operating in the normal mode can also be applied before or during the execution of the above procedure or the transmission of user data, when attempting to operate in the S&F mode, or when switching to the S&F mode.

[0201] Note that the above may be applied not only to the PLMN but also to the NPN (SNPN and / or PNI-NPN).

[0202] Also, the above may be applied only to 3GPP access, only to non-3GPP access, or to both 3GPP access and non-3GPP access.

[0203] Furthermore, this embodiment may be executed multiple times, or the second embodiment may be executed one or more times after this embodiment has been executed one or more times, or this embodiment may be executed one or more times after the second embodiment has been executed one or more times.

[0204] [4. Second Embodiment] Next, the behavior of the UE, satellite, and NW (e.g., MME, or AMF, or SMF, or UPF, etc., the same hereinafter) regarding the transmission of an MM message or SM message (also referred to as a first control message) or user data (also referred to as Mobile terminated (MT) data, downlink data) in the MM procedure or SM procedure started by the NW will be described.

[0205] Furthermore, in this embodiment, unless otherwise noted, the UE, and / or satellite, and / or NW will be described assuming that they support the S&F function or S&F mode.

[0206] Also, the UE may be able to communicate with a satellite equipped with the functions of a base station device.

[0207] The UE, and / or satellite, and / or NW may perform behavior based on the information they have grasped and / or the information they have transmitted and received.

[0208] In addition, the UE may send information indicating whether it supports the S&F function or the S&F mode to the satellite and / or the NW. The UE may include this information in NAS messages and / or control information and / or control messages of layers lower than the NAS layer (e.g., the physical layer, the MAC layer, the RLC layer, the PDCP layer, the RRC layer). For example, the control message of the RRC layer may be RRC signaling (also referred to as an RRC message), or the control information of the RRC layer may be system information. Also, the NAS message may be, for example, an MM message and / or an SM message. When the UE supports the S&F function or the S&F mode, the UE may send information indicating that it supports the S&F function or the S&F mode to the satellite and / or the NW. By receiving this control information, the satellite and / or the NW may recognize and store whether the UE supports the S&F function or the S&F mode.

[0209] In addition, the satellite may include information indicating whether it supports the S&F function or the S&F mode in NAS messages and / or control information and / or control messages of layers lower than the NAS layer, and send it to the UE and / or the NW. For example, the control message of the RRC layer may be RRC signaling (also referred to as an RRC message), or the control information of the RRC layer may be system information. Also, the NAS message may be, for example, an MM message and / or an SM message. When the satellite supports the S&F function or the S&F mode, the satellite may send information indicating that it supports the S&F function or the S&F mode to the UE and / or the NW. By receiving this control information, the UE and / or the NW may recognize and store whether the satellite supports the S&F function or the S&F mode.

[0210] In addition, the NW may include information indicating whether it supports the S&F function or the S&F mode in the NAS layer control information and / or control message, and transmit it to the UE and / or the satellite. For example, the NAS layer control message may be an MM message and / or an SM message. When the NW supports the S&F function or the S&F mode, the NW may transmit information indicating that it supports the S&F function or the S&F mode to the UE and / or the satellite. By receiving this control information, the UE and / or the satellite may recognize and store whether the NW supports the S&F function or the S&F mode.

[0211] In addition, the satellite may include information indicating whether it is operating in the S&F mode, and / or information indicating whether the service link is available, and / or information indicating whether the feeder link is available, and / or information indicating whether it is operating in the normal mode, and / or information indicating the time and / or period for applying the S&F mode (canceling the application of the normal mode), and / or information indicating the time and / or period for canceling the application of the S&F mode (applying the normal mode), in the NAS message and / or in the control information and / or control message of a lower layer than the NAS layer (e.g., physical layer, MAC layer, RLC layer, PDCP layer, RRC layer), and transmit it to the UE and / or NW. For example, the control message of the RRC layer may be an RRC message, or the control information of the RRC layer may be system information. Also, the NAS message may be, for example, an MM message and / or an SM message. Also, these information may be transmitted periodically or each time an event occurs. Here, the event may be, for example, when the mode is changed (when it becomes the S&F mode or the normal mode), when the state of the service link is changed (when the service link becomes available or unavailable), when the state of the feeder link is changed (when the feeder link becomes available or unavailable), etc. Here, the satellite may determine whether to transmit at least a part of these information to the UE based on the information indicating whether the UE and / or NW supports the S&F function or the S&F mode received from the UE and / or NW. For example, when receiving information indicating that the UE and / or NW supports the S&F function or the S&F mode, the satellite determines whether to transmit at least a part of these information to the UE. If it is determined to transmit, it may transmit to the UE and / or NW, and if it is determined not to transmit, it does not have to transmit to the UE and / or NW. Also, when at least a part of these information has not yet been transmitted to the UE and / or NW, or when at least a part of these information is updated, it may be determined to transmit to the UE and / or NW.Also, if at least a part of this information has already been transmitted to the UE and / or NW, or if the transmitted information has not been updated, it may be determined not to transmit it to the UE and / or NW.

[0212] Also, the information indicating whether operating in the S&F mode may be reinterpreted as the information indicating operating in the S&F mode or the information indicating not operating in the S&F mode. Also, the information indicating whether a service link is available (also referred to as whether there is connectivity of the service link) may be reinterpreted as the information indicating that the service link is available (also referred to as that there is connectivity of the service link) or the information indicating that the service link is not available (also referred to as that there is no connectivity of the service link). Also, the information indicating whether a feeder link is available (also referred to as whether there is connectivity of the feeder link) may be reinterpreted as the information indicating that the feeder link is available (also referred to as that there is connectivity of the feeder link) or the information indicating that the feeder link is not available (also referred to as that there is no connectivity of the feeder link). Also, the information indicating whether operating in the normal mode may be reinterpreted as the information indicating operating in the normal mode or the information indicating not operating in the normal mode.

[0213] For example, when the satellite is operating in the S&F mode, it may transmit to the UE and / or NW the information indicating operating in the S&F mode and / or the information indicating not operating in the normal mode. The UE and / or NW may recognize and store that it is operating in the S&F mode and / or not operating in the normal mode by receiving at least one of these control information.

[0214] Also, when the satellite is operating in the normal mode, it may transmit to the UE and / or the NW information indicating that it is operating in the normal mode and / or information indicating that it is not operating in the S&F mode. The UE and / or the NW may recognize and store that it is not operating in the S&F mode and / or that it is operating in the normal mode by receiving at least one of these control information.

[0215] Also, when the satellite is operating in the S&F mode, the service link is available, and the feeder link is not available, it may transmit to the UE information indicating that it is operating in the S&F mode and / or information indicating that it is not operating in the normal mode and / or information indicating that the service link is available and / or information indicating that the feeder link is not available. The UE and / or the NW may recognize and store that it is operating in the S&F mode and / or that it is not operating in the normal mode and / or that the service link is available and / or that the feeder link is not available by receiving at least one of these control information.

[0216] Also, when the satellite is operating in the S&F mode, the service link is not available, and the feeder link is available, it may transmit to the NW information indicating that it is operating in the S&F mode and / or information indicating that it is not operating in the normal mode and / or information indicating that the service link is not available and / or information indicating that the feeder link is available. The UE and / or the NW may recognize and store that it is operating in the S&F mode and / or that it is not operating in the normal mode and / or that the service link is not available and / or that the feeder link is available by receiving at least one of these control information.

[0217] Also, when the satellite is operating in the normal mode, the satellite may transmit to the UE and / or the NW information indicating that it is operating in the normal mode, and / or information indicating that it is not operating in the S&F mode, and / or information indicating that the service link is available, and / or information indicating that the feeder link is available. The UE and / or the NW may recognize and store that it is not operating in the S&F mode, and / or that it is operating in the normal mode, and / or that the service link is available, and / or that the feeder link is available, by receiving at least one of these control information.

[0218] Further, the satellite may transmit to the UE and / or the NW information indicating the time and / or period when the S&F mode is to be applied (the application of the normal mode is to be released), and / or information indicating the time and / or period when the application of the S&F mode is to be released (the normal mode is to be applied).

[0219] For example, when a satellite operating in the normal mode intends to operate in the S&F mode, it may transmit information indicating the time and / or period when the S&F mode is to be applied (the application of the normal mode is to be released). The UE and / or the NW may recognize and store the application of the S&F mode, and / or the release of the application of the normal mode, and / or the time and / or period when the S&F mode is to be applied, by receiving at least one of these control information.

[0220] Also, when a satellite operating in the S&F mode intends to operate in the normal mode, it may transmit information indicating the time and / or period when the application of the S&F mode is to be released (the normal mode is to be applied). The UE and / or the NW may recognize and store the release of the application of the S&F mode, and / or the application of the normal mode, and / or the time and / or period when the normal mode is to be applied, by receiving at least one of these control information.

[0221] Also, if a UE and / or NW operating in the normal mode does not receive information indicating that it is operating in the S&F mode and / or information indicating that it is not operating in the normal mode, it may recognize and remember that it is operating in the normal mode.

[0222] Also, if a UE and / or NW operating in the S&F mode does not receive information indicating that it is not operating in the S&F mode and / or information indicating that it is operating in the normal mode, it may recognize and remember that it is operating in the S&F mode.

[0223] Also, if a UE and / or NW operating in the normal mode does not receive information indicating that the service link is unavailable or information indicating that the feeder link is unavailable, it may be recognized and remembered as operating in the normal mode and may behave in the normal mode.

[0224] Also, if a UE and / or NW operating in the S&F mode does not receive information indicating that the service link is available and information indicating that the feeder link is available, it may be recognized and remembered as operating in the S&F mode and may behave in the S&F mode.

[0225] In addition, information indicating whether it is operating in the S&F mode, and / or information indicating whether the service link is available, and / or information indicating whether the feeder link is available, and / or information indicating whether it is operating in the normal mode, and / or information indicating the time and / or period when the S&F mode is applied, and / or information indicating the time and / or period when the application of the S&F mode is cancelled may be included in and transmitted / received in the following control messages 1 to 8, or may be included in and transmitted / received in a control message different from the following control messages 1 to 8. For example, before transmitting / receiving the first control message, it may be included in and transmitted / received in a control message different from the following control messages 1 to 8. Also, for example, after transmitting / receiving the first control message and before transmitting / receiving the eighth control message, it may be included in and transmitted / received in a control message different from the following control messages 1 to 8. Also, for example, after transmitting / receiving the eighth control message, it may be included in and transmitted / received in a control message different from the following control messages 1 to 8.

[0226] In addition, when the NW is operating in the S&F mode (when the service link is available but the feeder link is not available), the NW does not have to transmit, via the satellite, an MM message or an SM message (also referred to as the first control message) or user data (also referred to as Mobile terminated (MT) data, downlink data) in the MM procedure or SM procedure started by the NW to the UE.

[0227] In addition, when the NW is operating in the S&F mode (when the service link is not available but the feeder link is available), the NW does not have to transmit the first control message or user data to the UE via the satellite.

[0228] Also, when NW is operating in the S&F mode (when the service link is not available but the feeder link is available) or when operating in the normal mode, NW may transmit the first control message or user data to the UE via the satellite. Note that NW may start a timer (also referred to as the first timer) based on the transmission of the first control message or user data.

[0229] Also, when NW transmits the first control message or user data to the UE via the satellite when operating in the S&F mode (when the service link is not available but the feeder link is available), the satellite may transmit a control message (also referred to as the second control message) including information indicating that the first control message or user data could not be transferred as a response to the received first control message or user data, and / or information indicating that the first control message or user data could not be transferred because the feeder link is not available, etc., to NW. The second control message may be a control message (NAS message) at the NAS layer. Also, NW may recognize that the MM procedure or SM procedure started by NW is rejected based on the reception of the second control message and / or the control information included in the second control message.

[0230] Also, when NW is operating in the S&F mode (when the service link is not available but the feeder link is available), if the first control message or user data is transmitted to the UE via the satellite, the satellite may store the received first control message or user data for a predetermined period (also referred to as the first predetermined period). In this case, the satellite may transmit a control message (also referred to as the third control message) to the NW, which includes information indicating that the service link is not available, and / or information indicating that the first control message or user data has been stored, and / or information indicating that the first control message or user data has been stored because the service link is not available, and / or the first predetermined period (i.e., the storage period), etc. The third control message may be, for example, a NAS message. Note that the first predetermined period may be included in the third control message as a timer value. Also, based on the reception of the third control message and / or the control information included in the third control message, NW may recognize information indicating that the service link is not available, and / or information indicating that the first control message or user data has been stored, and / or information indicating that the first control message or user data has been stored because the service link is not available, and / or the first predetermined period, etc. Further, the first predetermined period may be a period predetermined in the standard or a period depending on the implementation of the satellite. Furthermore, based on the reception of the third control message and / or the control information included in the third control message, NW may start a timer (also referred to as the second timer). At this time, NW may start the second timer using the first predetermined period (or timer value) received from the satellite. Also, based on the transmission of the third control message and / or the control information included in the third control message, and / or the storage of the first control message or user data, the satellite may start a timer (also referred to as the third timer). At this time, the satellite may start the third timer using the first predetermined period (or timer value) transmitted to the NW.The third control message and / or at least one piece of control information included in the third control message may also be referred to as store indication or AS (Access Stratum) indication.

[0231] Furthermore, when the service link becomes unavailable within a first predetermined period, the satellite discards or deletes the first control message and / or the control information included in the first control message, or the user data received from and stored by the NW, and may transmit a second control message to the NW as a response to the received first control message. The satellite may manage the first predetermined period using a timer (third timer). That is, "when the service link becomes unavailable within the first predetermined period" may be construed as "when the service link becomes unavailable after starting the third timer using the first predetermined period and before the third timer expires". Also, when the NW receives the second control message and / or the control information included in the second control message before the second timer expires, the NW may recognize that the MM procedure or SM procedure started by the NW has been rejected, may stop the second timer operating in the NW, may recognize that the first control message or user data has not been transferred to the UE, may retransmit the first control message or user data immediately or after waiting for a predetermined period (also referred to as the second predetermined period), may execute retransmission of the same procedure or user data after waiting for the second predetermined period, may execute retransmission of the same procedure or user data when switching to the normal mode of operation, or may execute retransmission of the same procedure or user data when operating in the S&F mode but the service link has become available.

[0232] In addition, when the service link becomes available within a first predetermined period, the satellite may transmit (i.e., forward) to the UE the first control message received from and stored by the UE, and / or the control information included in the first control message, or user data. In this case, the satellite may transmit to the NW a control message (also referred to as a fourth control message) including information indicating that the first control message or user data has been forwarded due to the service link becoming available, or information indicating that the stored first control message or user data has been forwarded. The fourth control message may be, for example, a NAS message. Note that the satellite may manage the first predetermined period using a timer (a third timer). That is, "when the service link becomes available within the first predetermined period" may be read as "when the service link becomes available after starting the third timer using the first predetermined period and before the third timer expires". Note that the fourth control message, or at least one piece of control information included in the fourth control message, may be referred to as a forward indication or an AS (Access Stratum) indication. Further, based on the reception of the fourth control message and / or the control information included in the fourth control message, the NW may stop the second timer operating in the NW, may recognize that the first control message or user data has been forwarded to the UE, or may recognize that there is no need to retransmit the first control message or user data. Also, the satellite may stop the third timer operating in the satellite based on the transmission of the fourth control message and / or the control information included in the fourth control message. Note that when the service link becomes available may mean when switching to the operation in the normal mode, or when operating in the S&F mode but the service link becomes available.

[0233] Also, if NW does not receive a fourth control message from the satellite before the second timer in operation expires, NW may recognize that the MM procedure or SM procedure it initiates has been rejected, or may stop the second timer in operation, or may recognize that the first control message or user data has not been transferred to the UE, or may retransmit the first control message or user data immediately or after waiting for a second predetermined period, or may execute retransmission of the same procedure or user data after waiting for the second predetermined period, or may execute retransmission of the same procedure or user data when switching to operation in the normal mode, or may execute retransmission of the same procedure or user data when operating in the S&F mode but the service link becomes available.

[0234] In addition, when NW starts the second timer, it may interrupt the first timer in operation. Also, when NW stops the second timer or when the second timer expires, it may resume the count of the interrupted first timer.

[0235] Also, the UE may receive the first control message or user data from the satellite in the MM procedure or SM procedure initiated by NW.

[0236] Also, in the MM procedure or SM procedure initiated by NW, when the UE is operating in the S&F mode (the service link is not available but the feeder link is available) after receiving the first control message from the satellite, it does not have to transmit an MM message or an SM message (also referred to as the fifth control message) to NW via the satellite as a response to the first control message.

[0237] Also, when the UE is operating in the S&F mode (the service link is available but the feeder link is not available) after receiving the first control message from the satellite in the MM procedure or SM procedure initiated by the NW, the UE does not have to transmit the fifth control message to the NW via the satellite as a response to the first control message.

[0238] Also, when the UE is operating in the S&F mode (the service link is available but the feeder link is not available) after receiving the first control message from the satellite in the MM procedure or SM procedure initiated by the NW, or when the UE is operating in the normal mode, the UE may transmit the fifth control message to the NW via the satellite as a response to the first control message.

[0239] Also, when the UE is operating in the S&F mode (when the service link is available but the feeder link is not available), if the UE transmits a fifth control message to the NW via the satellite, the satellite may transmit a control message (also referred to as a sixth control message) to the UE, including information indicating that the fifth control message could not be relayed, and / or information indicating that the fifth control message could not be relayed because the feeder link is not available, as a response to the received fifth control message. The sixth control message may be, for example, a control message of a layer lower than the NAS layer (e.g., physical layer, MAC layer, RLC layer, PDCP layer, RRC layer), or may be a control message of the NAS layer (NAS message). Also, based on the reception of the sixth control message and / or the control information included in the sixth control message, the UE may recognize that the MM procedure or SM procedure initiated by the NW has been rejected, may stop the fourth timer operating in the UE, may recognize that the fifth control message has not been transferred to the NW, may retransmit the fifth control message immediately or after waiting for a predetermined period (also referred to as the fourth predetermined period), may retransmit the fifth control message when switching to the normal mode of operation, or may retransmit the fifth control message when the feeder link becomes available while operating in the S&F mode.

[0240] Also, when the UE is operating in the S&F mode (when the service link is available but the feeder link is not available), if the UE transmits the fifth control message to the NW via the satellite, the satellite may store the received fifth control message for a predetermined period (also referred to as the third predetermined period). In this case, the satellite may transmit a control message (also referred to as the seventh control message) to the UE, which includes information indicating that the service link is not available, and / or information indicating that the fifth control message has been stored, and / or information indicating that the fifth control message has been stored because the service link is not available, and / or the third predetermined period (i.e., the storage period), etc. The seventh control message may be, for example, a control message of a layer lower than the NAS layer (e.g., physical layer, MAC layer, RLC layer, PDCP layer, RRC layer), or it may be a NAS message. Note that the third predetermined period may be included in the seventh control message as a timer value. Also, based on the reception of the seventh control message and / or the control information included in the seventh control message, the UE may recognize information indicating that the service link is not available, and / or information indicating that the seventh control message has been stored, and / or information indicating that the seventh control message has been stored because the service link is not available, and / or the third predetermined period, etc. Also, the third predetermined period may be a period predetermined in the standard, or it may be a period depending on the implementation of the satellite. Furthermore, based on the reception of the seventh control message and / or the control information included in the seventh control message, the UE may start a timer (also referred to as the fourth timer). At this time, the UE may start the fourth timer using the third predetermined period (or timer value) received from the satellite. Also, based on the transmission of the seventh control message and / or the control information included in the seventh control message, and / or the storage of the fifth control message, the satellite may start a timer (also referred to as the fifth timer). At this time, the satellite may start the fifth timer using the third predetermined period (or timer value) transmitted to the UE.The seventh control message and / or at least one piece of control information included in the seventh control message may also be referred to as a store indication or an AS (Access Stratum) indication.

[0241] Furthermore, when the feeder link becomes unavailable within a third predetermined period, the satellite discards or deletes the fifth control message and / or the control information included in the fifth control message received and stored from the NW, and may transmit a sixth control message to the UE as a response to the received fifth control message. The satellite may manage the third predetermined period using a timer (the fifth timer). That is, "when the feeder link becomes unavailable within the third predetermined period" may be construed as "when the feeder link does not become available between the start of the fifth timer using the third predetermined period and the expiration of the fifth timer". Also, based on the reception of the sixth control message and / or the control information included in the sixth control message, the UE may recognize that the MM procedure or the SM procedure started by the NW has been rejected, may stop the fourth timer operating in the UE, may recognize that the fifth control message has not been transferred to the NW, may retransmit the fifth control message immediately or after waiting for a predetermined period (also referred to as the fourth predetermined period), may retransmit the fifth control message when switching to the normal mode of operation, or may retransmit the fifth control message when operating in the S&F mode but the feeder link has become available.

[0242] Also, when the feeder link becomes available within a third predetermined period, the satellite may transmit (i.e., forward) to the NW the fifth control message received from and stored in the NW, and / or the control information included in the fifth control message. In this case, the satellite may transmit to the UE a control message (also referred to as the eighth control message) including information indicating that the fifth control message has been forwarded because the feeder link has become available, or information indicating that the stored fifth control message has been forwarded. The eighth control message may be, for example, a control message of a layer lower than the NAS layer (e.g., physical layer, MAC layer, RLC layer, PDCP layer, RRC layer), or may be a NAS message. Note that the satellite may manage the third predetermined period using a timer (the fifth timer). That is, "when the feeder link becomes available within a third predetermined period" may be read as "when the feeder link becomes available after starting the fifth timer using the third predetermined period and before the fifth timer expires". Note that the eighth control message, or at least one control information included in the eighth control message, may be referred to as a forward indication, or an AS (Access Stratum) indication. Further, based on the reception of the eighth control message and / or the control information included in the eighth control message, the UE may stop the fourth timer operating in the UE, may recognize that the fifth control message has been forwarded to the NW, or may recognize that it is not necessary to retransmit the fifth control message. Also, based on the transmission of the eighth control message and / or the control information included in the eighth control message, the satellite may stop the fifth timer operating in the satellite. Note that when the feeder link becomes available may mean when switching to the operation in the normal mode, or when operating in the S&F mode but the feeder link has become available.

[0243] Also, if the UE does not receive the eighth control message from the satellite before the fourth timer in operation expires, the UE may recognize that the MM procedure or SM procedure initiated by the NW has been rejected, or may stop the fourth timer operating in the UE, or may recognize that the fifth control message has not been transferred to the NW, or may retransmit the fifth control message immediately or after waiting for only a fourth predetermined period, or may retransmit the fifth control message when switching to operation in the normal mode, or may retransmit the fifth control message when operating in the S&F mode but the service link becomes available.

[0244] Also, if the NW receives the fifth control message from the UE via the satellite before the first timer in operation expires, the NW may recognize that the MM procedure or SM procedure initiated by the NW has ended normally.

[0245] Also, if the NW does not receive the fifth control message from the UE via the satellite before the first timer in operation expires, the NW may recognize that the MM procedure or SM procedure initiated by the NW has not ended normally.

[0246] Also, if the NW receives the fourth control message from the UE via the satellite before the first timer in operation expires, the NW may recognize that the MM procedure or SM procedure initiated by the NW has ended normally.

[0247] Also, the first control message may be an unregistration request message, and the fifth control message may be an unregistration acceptance message. In this case, the first timer may be the T3522 timer.

[0248] Also, the first control message may be a setting update command message, and the fifth control message may not exist. In this case, the first timer may not exist.

[0249] Also, the first control message may be a configuration update command message, and the fifth control message may be a configuration update completion message. In this case, the first timer may be the T3555 timer.

[0250] Also, the first control message may be a downlink (DL) NAS transport message, and the fifth control message may not exist. In this case, the first timer may not exist.

[0251] Also, the first control message may be a paging request message or a paging message, and the fifth control message may be a service request message, or a CP service request message, or a registration request message. In this case, the first timer may be the T3513 timer.

[0252] Also, the first control message may be a notification message, and the fifth control message may be a notification response message, or a service request message, or a CP service request message, or a registration request message. In this case, the first timer may be the T3565 timer.

[0253] Also, the first control message may be a PDU session change command message, and the fifth control message may be a PDU session change completion message or a PDU session change command rejection message. In this case, the first timer may be the T3591 timer.

[0254] Also, the first control message may be a PDU session release command message, and the fifth control message may be a PDU session release completion message. In this case, the first timer may be the T3592 timer.

[0255] Also, the first control message may be a detach request message, and the fifth control message may be a detach acceptance message. In this case, the first timer may be T3422.

[0256] Also, the first control message may be an Activate Default EPS Bearer Context Request message, and the fifth control message may be an Activate Default EPS Bearer Context Accept message or an Activate Default EPS Bearer Context Reject message. In this case, the first timer may be T3485.

[0257] Also, the first control message may be an Activate Dedicated EPS Bearer Context Request message, and the fifth control message may be an Activate Dedicated EPS Bearer Context Accept message or an Activate Dedicated EPS Bearer Context Reject message. In this case, the first timer may be T3485.

[0258] Also, the first control message may be a Modify EPS Bearer Context Request message, and the fifth control message may be a Modify EPS Bearer Context Accept message or a Modify EPS Bearer Context Reject message. In this case, the first timer may be T3486.

[0259] Also, the first control message may be a Deactivate EPS Bearer Context Request message, and the fifth control message may be a Deactivate EPS Bearer Context Accept message. In this case, the first timer may be T3495.

[0260] Also, when the UE receives the second control message from the satellite, instead of starting the second timer, it may extend the first timer that is already running. For example, the UE may extend the first timer indefinitely until it receives the fifth control message, or it may extend the timer for a certain period of time.

[0261] Also, the first to eighth control messages may include user data as well as control information.

[0262] Also, the behaviors of the above UE operating in the S&F mode, the satellite, and the NW can be applied even before or during the execution of the above procedure or user data transmission, when attempting to operate in the normal mode, or when switching to the normal mode of operation.

[0263] Also, the behaviors of the above UE operating in the normal mode, the satellite, and the NW can be applied even before or during the execution of the above procedure or user data transmission, when attempting to operate in the S&F mode, or when switching to the S&F mode of operation.

[0264] Note that the above may be applied not only to the PLMN but also to the NPN (SNPN and / or PNI-NPN).

[0265] Also, the above may be applied only to 3GPP access, only to non-3GPP access, or to both 3GPP access and non-3GPP access.

[0266] Note that this embodiment may be executed multiple times, or the first embodiment may be executed one or more times after this embodiment has been executed one or more times, or this embodiment may be executed one or more times after the first embodiment has been executed one or more times.

[0267] [4. Variation Example] A program that operates in an apparatus according to an aspect of the present invention may be a program that controls a Central Processing Unit (CPU) or the like to function a computer so as to realize the functions of the embodiments according to the present invention. The program or the information handled by the program is temporarily stored in a volatile memory such as a Random Access Memory (RAM), a non-volatile memory such as a flash memory, a Hard Disk Drive (HDD), or other storage device systems.

[0268] Furthermore, a program for realizing the functions of the embodiments related to one aspect of the present invention may be recorded on a computer-readable recording medium. The functions may be realized by causing a computer system to read and execute the program recorded on this recording medium. Here, the "computer system" shall mean a computer system built into a device, including hardware such as an operating system and peripheral devices. Also, the "computer-readable recording medium" may be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a medium that dynamically holds a program for a short time, or any other recording medium readable by a computer.

[0269] Moreover, each functional block or various features of the devices used in the above-described embodiments may be implemented or executed by an electric circuit, for example, an integrated circuit or a plurality of integrated circuits. The electric circuit designed to execute the functions described in this specification may include a general-purpose use processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or a combination thereof. The general-purpose use processor may be a microprocessor, or a conventional type processor, a controller, a microcontroller, or a state machine. The above-described electric circuit may be composed of a digital circuit or an analog circuit. Also, when an integrated circuit technology that replaces the current integrated circuit appears due to the progress of semiconductor technology, one or more aspects of the present invention may also use the new integrated circuit by this technology.

[0270] Note that the present invention of this application is not limited to the above-described embodiments. In the embodiments, an example of the device is described, but one aspect of the present invention of this application is not limited thereto, and may be applied to stationary or non-mobile electronic devices installed indoors and outdoors, for example, terminal devices or communication devices such as AV devices, kitchen devices, cleaning and washing devices, air conditioning devices, office devices, vending machines, and other living devices.

[0271] The above has described in detail the embodiments of the present invention with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of the present invention are also included. In addition, one aspect of the present invention can be variously modified within the scope shown in the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Further, configurations in which elements described in the above embodiments are replaced with elements having the same effect are also included.

Description of Reference Numerals

[0272] 1 Mobile communication system 10 UE_A 30 PGW-U 32 PGW-C 35 SGW 40 MME 45 eNB 50 HSS 60 PCRF 80 Access network_A 90 Core network_A 120 Access network_B 122 gNB 130 UPF 132 SMF 140 AMF 150 UDM 160 PCF 170 N3IWF 190 Core network_B

Claims

【Claim 1】 A UE comprising a transceiver unit and a control unit, wherein the UE is capable of communicating with a satellite equipped with a base station function, the transceiver unit, transmits information indicating that the satellite supports the S&F mode to the satellite, receives from the satellite information indicating that a registration request message has been stored, information indicating that a feeder link is not available, and a timer value, the control unit sets the timer value in a timer and starts the timer, when the transceiver unit receives information indicating that the registration request message could not be transferred before the timer expires, the control unit retransmits the registration request message, characterized in that it is a UE.

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