UE (user equipment)

Abstract

To provide a UE that can appropriately execute procedures for session management by transmitting and receiving appropriate control information between a network and the UE, and by performing appropriate message retransmission and timer management based on the control information when the UE, a satellite, and the network that support a store-and-forward function execute each procedure for session management using the store-and-forward function.SOLUTION: A UE receives first information from a network indicating that a store-and-forward function is to be used. Based on the first information, even if repetition of transmission of a PDU session establishment request message and of start and expiration of a first timer associated with the transmission of the PDU session establishment request message reaches five or more times, the UE does not stop a PDU session establishment procedure and repeats the PDU session establishment procedure until the UE receives a response message from the network.SELECTED DRAWING: Figure 7

Description

Technical Field

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

Background Art

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

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

[0004] In the 5GS (5G System), in order to provide a variety of services, a new core network, 5GCN (5G Core Network), is being considered. Furthermore, an architecture for 5G communication via a satellite (Satellite; also simply referred to as "satellite") is being considered.

[0005] Currently, in such a communication architecture that uses a satellite as a radio technology (radio access technology) for connecting a user terminal (UE) and a core network, studies are being carried out on the conventional extension of procedures, messages, or parameters in consideration of the characteristics of the radio connection via the satellite. More specifically, for example, as new functions of 5G communication via a satellite, the installation of a base station function on the satellite, the support of the store-and-forward function by the satellite and the UE, the support of UE-satellite-UE communication, etc. are being considered.

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

[0007] One aspect of this embodiment is made in view of the above circumstances, and its purpose is that when a UE, a satellite, and a network supporting the store-and-forward function execute each procedure for session management using the store-and-forward function, appropriate transmission and reception of control information between the network and the UE considering the store-and-forward function, retransmission of appropriate messages based on the control information, and timer management are executed, and each procedure for session management is appropriately executed and completed without interruption. A method is provided for this purpose.

Means for Solving the Problem

[0008] A UE (User Equipment) according to one aspect of this embodiment is a UE including a transceiver, a control unit, and a storage unit. The transceiver transmits capability information indicating that the UE supports the store-and-forward function to the network, and receives first information indicating that the network uses the store-and-forward function from the network. The control unit, based on the first information, repeats the transmission of a PDU (Protocol Data Unit) session establishment request message by the transceiver, the start and expiration of a first timer associated with the transmission of the PDU session establishment request message, even when the number of repetitions reaches 5 or more, without aborting the PDU session establishment procedure, and repeats until a response message is received from the network. A UE (User Equipment) according to one aspect of this embodiment is a UE including a transceiver, a control unit, and a storage unit. The transceiver transmits to the network the capability information indicating that the UE supports the store-and-forward function and one or more S-NSSAIs (Single Network Slice Selection Assistance Information) that support communication by the store-and-forward function, included in the requested NSSAI (Network Slice Selection Assistance Information). The transceiver receives from the network the first information indicating that the network uses the store-and-forward function and an allowed NSSAI including one or more S-NSSAIs that support communication by the store-and-forward function. When the UE executes a PDU (Protocol Data Unit) session establishment procedure for an S-NSSAI that supports the store-and-forward function included in the allowed NSSAI, the control unit, based on the first information, repeats the transmission of a PDU session establishment request message by the transceiver, the start and expiration of a first timer associated with the transmission of the PDU session establishment request message, even when the number of repetitions reaches 5 or more, without aborting the PDU session establishment procedure, and repeats until a response message is received from the network.

Advantages of the Invention

[0009] According to one aspect of the present embodiment, in each procedure for session management when a UE and a network execute communication using the store-and-forward function provided by a satellite via the satellite, means for transmitting and receiving appropriate control information between the network and the UE, appropriate timer management based on the control information, and / or appropriate retransmission of messages, and a method for executing appropriate processing based on the control information are provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

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

[0012] [1. Overview 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.

[0013] As shown in FIG. 1, the mobile communication system 1 is described as being composed of UE_A10, access network_A80, core network_A90, PDN (Packet Data Network)_A5, access network_B120, core network_B190, and DN (Data Network)_A6.

[0014] Hereinafter, these devices / functions may be described with symbols omitted, such as UE, access network_A, core network_A, PDN, access network_B, core network_B, DN, etc.

[0015] Also, as shown in FIG. 2, devices / functions such as UE_A10, E-UTRAN80, MME40, SGW35, PGW-U30, PGW-C32, PCRF60, HSS50, 5G AN120, AMF140, UPF130, SMF132, PCF160, UDM150, N3IWF170, and the interfaces connecting these devices / functions to each other are described.

[0016] Hereinafter, these devices / functions may be described with symbols omitted, such as UE, E-UTRAN, MME, SGW, PGW-U, PGW-C, PCRF, HSS, 5G AN, AMF, UPF, SMF, PCF, UDM, N3IWF, etc.

[0017] Note that the EPS (Evolved Packet System), which is a 4G system, is composed of the access network_A and the core network_A, and may further include a UE and / or a PDN. Also, the 5GS (5G System), which is a 5G system, is composed of a UE, an access network_B, and a core network_B, and may further include a DN.

[0018] A UE is a device capable of connecting to network services via 3GPP access (also referred to as a 3GPP access network, 3GPP AN) and / or non-3GPP access (also referred to as a non-3GPP access network, non-3GPP AN). The UE may be a terminal device capable of wireless communication such as a mobile phone or a smartphone, and may be a terminal device capable of connecting to both EPS and 5GS. The UE may be equipped with a UICC (Universal Integrated Circuit Card) or an eUICC (Embedded UICC). Note that the UE may be referred to as a user device or a terminal device.

[0019] In addition, access network_A corresponds to an E-UTRAN (Evolved Universal Terrestrial Radio Access Network) and / or a wireless LAN access network. One or more eNBs (evolved Node B) 45 are arranged in the E-UTRAN. Note that hereinafter, the eNB 45 may be described with the symbol omitted as eNB. Also, in the case of multiple eNBs, each eNB is connected to each other, for example, by an X2 interface. Also, one or more access points are arranged in the wireless LAN access network.

[0020] In addition, Access Network_B is compatible with a 5G Access Network (5G AN). The 5G AN is composed of an NG-RAN (NG Radio Access Network) and / or a non-3GPP access network. One or more gNBs (NR Node B) 122 are arranged in the NG-RAN. Hereinafter, the gNB 122 may be described by omitting the symbol like gNB. The gNB is a node that provides the NR (New Radio) user plane and control plane to the UE, and is a node connected to the 5GCN via an NG interface (including the N2 interface or the N3 interface). That is, the gNB is a base station device newly designed for 5GS and has functions different from those of the base station device (eNB) used in the EPS which is a 4G system. Also, when there are a plurality of gNBs, each gNB is connected to each other by, for example, an Xn interface.

[0021] In addition, the non-3GPP access network may be an untrusted non-3GPP access network or a trusted non-3GPP access network. Here, the untrusted non-3GPP access network may be a non-3GPP access network that does not perform security management within the access network, such as a public wireless LAN. On the other hand, the trusted non-3GPP access network may be an access network defined by 3GPP and may be equipped with a TNAP (trusted non-3GPP access point) and a TNGF (trusted non-3GPP Gateway function).

[0022] 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. Also, the nodes arranged in Access Network_B may be collectively referred to as NG-RAN nodes.

[0023] Also, hereinafter, the access network_A, and / or the access network_B, and / or the devices included in the access network_A, and / or the devices included in the access network_B may be referred to as an access network or an access network device.

[0024] Also, the 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.

[0025] Also, the core network_B corresponds to the 5GCN (5G Core Network). In the 5GCN, for example, an AMF (Access and Mobility Management Function), a UPF (User Plane Function), an SMF (Session Management Function), a PCF (Policy Control Function), a UDM (Unified Data Management), etc. are arranged. Here, the 5GCN may be expressed as 5GC.

[0026] Also, in this specification, the core network_A, and / or the core network_B, and / or the devices included in the core network_A, and / or the devices included in the core network_B may be referred to as a core network, or a core network device or an in-core network device, or a network, or NW. In other words, for example, when referred to as a network or NW in this specification, it may mean the core network_A or the core network_B.

[0027] The core network (Core Network_A and / or Core Network_B) may be an IP mobile communication network operated by a mobile network operator (MNO) that connects 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 or virtual mobile service providers such as MVNO (Mobile Virtual Network Operator) and MVNE (Mobile Virtual Network Enabler).

[0028] Also, 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 a communication service 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 to and from the PDN may mean transmitting and receiving user data to and from 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.

[0029] Also, hereinafter, at least a part of access network_A, core network_A, PDN, access network_B, core network_B, DN, and / or one or more devices included therein may be referred to as a network or a network device. That is, when a network and / or a network device transmits and receives messages and / or executes procedures, it means that at least a part of access network_A, core network_A, PDN, access network_B, core network_B, DN, and / or one or more devices included therein transmit and receive messages and / or execute procedures.

[0030] Also, the UE can be connected to the access network. Also, the UE can be connected to the core network via the access network. Further, the UE can be connected to the PDN or DN via the access network and the core network. That is, the UE can transmit and receive (communicate) user data with the PDN or DN. When transmitting and receiving user data, not only IP (Internet Protocol) communication but also non-IP communication may be used.

[0031] Here, IP communication is data communication using IP, and data is transmitted and received 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 is data communication that does not use IP, and data is transmitted and received in a format different from the structure of an IP packet. For example, non-IP communication may be data communication realized by transmitting and receiving application data without an IP header, or may transmit and receive user data transmitted and received by the UE with another header such as a MAC header or an Ethernet (registered trademark) frame header.

[0032] In addition, the 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, the core network_A and / or core network_B may include an AUSF (Authentication Server Function) or an AAA (Authentication, authorization, and accounting) server (AAA-S).

[0033] Here, the AUSF is a core network device having an authentication function for 3GPP access and non-3GPP access. Specifically, it is a network function unit that receives an authentication request for 3GPP access and / or non-3GPP access from the UE and executes an authentication procedure.

[0034] In addition, the AAA server is a device having an authentication, authorization, and accounting function 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 the 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.

[0035] In FIG. 2, for 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, etc.

[0036] UPF_A235 is connected to the DN, SMF, other UPFs, and the access network. UPF_A235 may serve as an anchor for intra-RAT mobility or inter-RAT mobility, perform packet routing & forwarding, support the UL CL (Uplink Classifier) function for routing multiple traffic flows for one DN, support the Branching point function for multi-homed PDU sessions, perform QoS processing for the user plane, verify uplink traffic, buffer downlink packets, trigger the Downlink Data Notification function, etc. Also, UPF_A235 may be a relay device that transfers user data as a gateway between the DN and the core network_B190. Note that UPF_A235 may also be a gateway for IP communication and / or non-IP communication. Furthermore, UPF_A235 may have the function of transferring IP communication or may have the function of converting non-IP communication and IP communication. Additionally, multiple gateways arranged may also be gateways connecting the core network_B190 and a single DN. Note that UPF_A235 may be provided with connectivity to other NFs and may be connected to each device via other NFs.

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

[0038] Also, UPF130 may be the same device as UPF_A235. Note that UPF130 and UPF_A235 may be described with the symbol omitted, similar to UPF.

[0039] [2. Configuration of Each Device] Next, the configuration of each device (UE, and / or access network device, and / or core network device) used in each embodiment will be described with reference to the drawings. 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.

[0040] Note that each storage unit (storage unit_A340, storage unit_A440, storage unit_B540, storage unit_A640, storage unit_B740) within each device / function that appears below is composed of, for example, a semiconductor memory, SSD (Solid State Drive), HDD (Hard Disk Drive), etc. Also, each storage 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 (for example, UE, and / or access network device, and / or core network device, and / or PDN, and / or DN). Also, each storage 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 storage unit may store this information for each UE. Also, when interworking between 5GS and EPS occurs, each storage unit can store the control messages and user data transmitted and received between the devices / functions included in 5GS and / or EPS. At this time, not only what is transmitted and received via the N26 interface, but also what is transmitted and received without passing through the N26 interface can be stored.

[0041] [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 storage unit _A340. The control unit _A300, the transceiver unit _A320, and the storage unit _A340 are connected via a bus. The transceiver unit _A320 is connected to the antenna 310.

[0042] The control unit _A300 is a functional unit that controls the operations and functions of the entire UE. The control unit _A300 reads and executes various programs stored in the storage unit _A340 as necessary to implement various processes in the UE.

[0043] The transceiver 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 transceiver unit _A320.

[0044] Describing in detail with reference to FIG. 2, the UE can communicate with a base station device (eNB) in the E-UTRAN via the LTE-Uu interface by using the transceiver unit _A320. Also, the UE can communicate with a base station device (gNB) in the 5G AN by using the transceiver unit _A320. Further, the UE can transmit and receive NAS (Non-Access-Stratum) messages with the AMF via the N1 interface by using the transceiver 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.

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

[0046] [2.2. Device Configuration of gNB] Next, an example of the gNB device configuration will be described with reference to FIG. 4. The gNB is composed of a control unit _B500, an antenna 510, a network connection unit _B520, a transceiver unit _B530, and a memory unit _B540. The control unit _B500, the network connection unit _B520, the transceiver unit _B530, and the memory unit _B540 are connected via a bus. The transceiver unit _B530 is connected to the antenna 510.

[0047] 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 memory unit _B540 as necessary.

[0048] The network connection unit _B520 is a functional unit for the gNB to communicate with the AMF and / or UPF. That is, the gNB can transmit and receive user data and / or control information to and from the AMF and / or UPF using the network connection unit _B520.

[0049] The transceiver unit _B530 is a functional unit for wireless communication with the UE via the antenna 510. That is, the gNB can transmit and receive user data and / or control information to and from the UE using the transceiver unit _B530.

[0050] 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.

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

[0052] [2.3. AMF Device Configuration] Next, an example of the device configuration of the AMF will be described with reference to FIG. 5. The AMF is composed of a control unit _B700, a network connection unit _B720, and a storage unit _B740. The control unit _B700, the network connection unit _B720, and the storage unit _B740 are connected via a bus. The AMF may be a node that handles the control plane. Also, the AMF may be a network device. In other words, for example, in this specification, the network device may mean the AMF.

[0053] 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 and executing various programs stored in the storage unit _B740 as necessary.

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

[0055] Referring to FIG. 2 for a detailed description, the AMF within the 5G CN can communicate with the gNB via the N2 interface, with the UDM via the N8 interface, with the SMF via the N11 interface, and with the PCF via the N15 interface by using the network connection unit_A620. Also, the AMF can send and receive NAS messages with the UE via the N1 interface by using the network connection unit_A620. However, since the N1 interface is logical, in reality, 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.

[0056] The storage unit_B740 is a functional unit for storing programs, user data, control information, etc. necessary for each operation of the AMF.

[0057] Furthermore, 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 integrity protecting 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 the UE connected via the N3IWF, etc.

[0058] 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 the non-registered state (RM-DEREGISTERED state) and the registered state (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 the 5GMM state (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.

[0059] 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 sending and receiving user data and control messages, or may respond to paging. Furthermore, 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.

[0060] Furthermore, 5GMM-DEREGISTERED may be a state where each device has not established a 5GMM context, or a state where the location information of UE_A10 is not grasped by the network, 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.

[0061] Also, 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.

[0062] Furthermore, in connection management, the CM state in 3GPP access and the CM state in non-3GPP access may be managed separately. In this case, the CM state in 3GPP access may include a non-connected state in 3GPP access (CM-IDLE state over 3GPP access) and a connected state in 3GPP access (CM-CONNECTED state over 3GPP access). Furthermore, the CM state in non-3GPP access may include a non-connected state in non-3GPP access (CM-IDLE state over non-3GPP access) and a connected state in non-3GPP access (CM-CONNECTED state over non-3GPP access). Note that the non-connected state may be expressed as the idle mode, and the connected state mode may be expressed as the connected mode.

[0063] Furthermore, the CM state may 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. Further, 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. Further, 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 be expressed as the idle mode, and the 5GMM-CONNECTED mode may be expressed as the connected mode.

[0064] 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.

[0065] Note that the N3IWF is a device and / or function disposed between non-3GPP access and the 5GCN when the UE connects to the 5GS via non-3GPP access.

[0066] [2.4. SMF Device Configuration] Next, an example of the device configuration of the SMF will be described with reference to FIG. 5. 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.

[0067] 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.

[0068] 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 send and receive user data and / or control information to and from the AMF, and / or UPF, and / or PCF, and / or UDM using the network connection unit _B720.

[0069] Referring to FIG. 2 for a detailed description, 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.

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

[0071] 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.

[0072] [2.5. UPF Device Configuration] Next, an example of the UPF device configuration will be described with reference to FIG. 5. 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.

[0073] The control unit _B700 is a functional unit that controls the operation and functions of the entire UPF. The control unit _B700 reads and executes various programs stored in the storage unit _B740 as needed to realize various processes in the UPF.

[0074] The network connection unit _B720 is a functional unit for the UPF to connect to a 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 unit _B720 to send and receive user data and / or control information to and from a base station device (gNB) within the 5G AN, and / or the SMF, and / or the DN.

[0075] Referring to FIG. 2 and explaining in detail, the UPF within the 5GCN can communicate with the gNB via the N3 interface by using the network connection part _A620, can communicate with the SMF via the N4 interface, can communicate with the DN via the N6 interface, and can communicate with other UPFs via the N9 interface.

[0076] The storage part _B740 is a functional part for storing programs, user data, control information, etc. necessary for each operation of the UPF.

[0077] 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 transferring packets, a UL CL (Uplink Classifier) function that supports routing of multiple traffic flows for one DN, a Branching point function that supports multi-homed PDU sessions, 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.

[0078] Also, the UPF may be a gateway for IP communication and / or non-IP communication. Also, the UPF may have a function of transferring IP communication, or may have a function of converting non-IP communication and IP communication. Furthermore, the multiple gateways arranged may be gateways connecting the core network _B and a single DN. Note that the UPF may be provided with connectivity to other NFs and may be connected to each device via other NFs.

[0079] The user plane is user data transmitted and received between the UE and the network. The user plane may be transmitted and received using a PDN connection or a PDU session. Further, in the case of EPS, the user plane may be transmitted and received using the LTE-Uu interface, and / or the S1-U interface, and / or the S5 interface, and / or the S8 interface, and / or the SGi interface. Further, in the case of 5GS, the user plane may be transmitted and received via the interface between the UE and the NG RAN, and / or the N3 interface, and / or the N9 interface, and / or the N6 interface. Hereinafter, the user plane may be expressed as the U-Plane.

[0080] Furthermore, the control plane is control messages transmitted and received for performing communication control of the UE, etc. The control plane may be transmitted and received using the NAS (Non-Access-Stratum) signaling connection between the UE and the MME. Further, in the case of EPS, the control plane may be transmitted and received using the LTE-Uu interface and the S1-MME interface. Further, in the case of 5GS, the control plane may be transmitted and received using the interface between the UE and the NG RAN and the N2 interface. Hereinafter, the control plane may be expressed as the control plane or the C-Plane.

[0081] Furthermore, the U-Plane (User Plane; UP) may be a communication path for transmitting and receiving user data and may be composed of a plurality of bearers. Further, the C-Plane (Control Plane; CP) may be a communication path for transmitting and receiving control messages and may be composed of a plurality of bearers.

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

[0083] The PCF has functions such as providing policy rules.

[0084] Also, the UDM has functions such as an Authentication credential processing function, a user identification processing function, an access authentication function, a registration / mobility management function, and a subscription management function.

[0085] Also, the PCRF is connected to the PGW and / or the PDN and has functions such as performing QoS management for data delivery. For example, it performs QoS management for the communication path between UE_A10 and the PDN. Furthermore, the PCRF may be a device that creates and / or manages PCC (Policy and Charging Control) rules and / or routing rules used when each device transmits and receives user data.

[0086] Also, the HSS is connected to the MME and / or the SCEF and has functions such as performing subscriber information management. The subscriber information of the HSS is referred to, for example, during the access control of the MME. Furthermore, the HSS may be connected to a location management device different from the MME.

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

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

[0089] 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) within the network executes message transmission / reception and / or processing. Conversely, when a device within the network executes message transmission / reception and / or processing, it may mean that the network executes message transmission / reception and / or processing.

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

[0091] An MM (Mobility management) message (also referred to as an NAS MM message) may be an NAS message used for MM procedures, and may be a control message transmitted and received between UE_A10 and AMF_A240. Further, the MM message may include a Registration request message, a Registration accept message, a Registration reject message, a De-registration request message, a De-registration accept message, a configuration update command message, a configuration update complete message, a Service request message, a Service accept message, a Service reject message, a Notification message, a Notification response message, etc. Also, the procedure for MM or the MM procedure may include a Registration procedure, a De-registration procedure, a Generic UE configuration update procedure (also simply referred to as a UE configuration update procedure), an authentication and / or authorization procedure, a Service request procedure, a Paging procedure, a Notification procedure.

[0092] The 5GS (5G System) service is a connection service provided using the core network_B190. Furthermore, the 5GS service may be a service different from the EPS service or a service similar to the EPS service.

[0093] 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.

[0094] The PDN (Packet Data Network) type indicates the type of the PDN connection and includes 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 by a communication method other than IP communication.

[0095] A PDU (Protocol Data Unit / Packet Data Unit) session can be defined as the association between a DN that provides a PDU connectivity service and a UE, but it can also be a connectivity established between the UE and an external gateway. In 5GS, the UE can establish a PDU session via access network_B and core network_B, and use the PDU session to send and receive user data with the DN. Here, this external gateway can be a UPF, SCEF, etc. The UE can use the PDU session to send and receive user data with devices such as application servers located in the DN. In addition, each device (UE, and / or access network device, and / or core network device) may manage one or more pieces of identification information associated with the PDU session. These pieces of identification information may include one or more of DNN, QoS rules, PDU session type, application identification information, NSI identification information, access network identification information, and SSC mode, or may further include other information. Furthermore, when multiple PDU sessions are established, the identification information associated with each PDU session may have the same content or different content.

[0096] DNN (Data Network Name) may be identification information for identifying an external network such as a core network and / or a DN. Furthermore, DNN can also be used as information for selecting a gateway such as a PGW / UPF that connects to core network B190. Furthermore, DNN may be equivalent to an APN (Access Point Name).

[0097] The PDU (Protocol Data Unit / Packet Data Unit) session type indicates the type of the PDU session, and there are 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, etc. in the DN using the 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 the UE can use both IPv4 and IPv6.

[0098] PLMN (Public land mobile network) is a communication network that provides mobile wireless communication services. PLMN is a network managed by an operator who is a communication carrier, 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) may be the Home PLMN (HPLMN). Furthermore, the UE may hold an Equivalent HPLMN list (also referred to as an equivalent HPLMN) for identifying one or more EPLMNs (Equivalent HPLMN; also referred to as an equivalent HPLMN) in the USIM. A PLMN different from the HPLMN and / or EPLMN may be a VPLMN (Visited PLMN). The PLMN in which the UE's registration is successful may be an RPLMN (Registered PLMN).

[0099] 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. Note that the tracking area may be composed of multiple cells. Furthermore, the tracking area may be a range in which control messages such as paging are broadcast, or a range in which UE_A10 can move without performing a handover procedure. Furthermore, the tracking area may be a routing area, a location area, or anything similar. Hereinafter, the tracking area may be a TA (Tracking Area). The tracking area may be identified by a TAI (Tracking Area Identity) composed of a TAC (Tracking area code) and a PLMN.

[0100] The registration area (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 within one or more TAs included in the registration area without transmitting or receiving signals for tracking area update. In other words, the registration area may be a group of information indicating an area in which 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.

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

[0102] Lists of 5GS forbidden tracking areas may be lists of 5GS forbidden tracking areas for roaming and / or lists of 5GS forbidden tracking areas for regional provision of service that are memorized by UEs not operating in SNPN access operation mode. In other words, UEs not operating in SNPN access operation mode must memorize lists of 5GS forbidden tracking areas for roaming and / or lists of 5GS forbidden tracking areas for regional service provision. Further, the UE needs to search for appropriate cells belonging to TAs not included in the list of 5GS forbidden tracking areas within the same PLMN.

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

[0104] In addition, the UE may store the Tracking Area Identity (TAI) in the list of 5GS forbidden tracking areas for regional provision of service in order to prevent repeated access attempts to cells in forbidden tracking areas. Further, the list of 5GS forbidden tracking areas for regional provision of service may be deleted when the UE's power is turned off, when the SIM is removed, or periodically (for a period in the range of 12 to 24 hours).

[0105] Also, the information indicating the 5GS prohibited tracking area for roaming may be sent to the UE by including one or more Forbidden TAI (also referred to as prohibited TAI) for the list of "5GS forbidden tracking areas for roaming" in an information element (Forbidden TAI(s) for the list of "5GS forbidden tracking areas for roaming" IE (Information Element)) included in the message sent by the network.

[0106] Also, the 5GS prohibited tracking area for regional service provision may be included in an information element (Forbidden TAI(s) for the list of "5GS forbidden tracking areas for regional provision of service" IE (Information Element)) including one or more Forbidden TAI for the list of "5GS forbidden tracking areas for regional provision of service" included in the message sent by the network, and may be sent to the UE.

[0107] The UE ID is information for identifying the UE. 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). Or, the UE ID may be other information set within the application or network. Furthermore, the UE ID may be information for identifying the user.

[0108] NTN (Non-terrestrial network) is an NG-RAN composed of multiple gNBs, and provides non-terrestrial NR access to the UE by means of an NTN payload and an NTN gateway mounted on an NTN transmission means such as a satellite or an aircraft installed in outer space or in the air.

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

[0110] Also, the NTN gateway is an earth station installed on the earth's surface, and provides a connection to the NTN payload using the feeder link. Furthermore, the NTN gateway may be a TNL (Transport Network Layer) node.

[0111] In other words, for example, "NR connection via satellite" (NR satellite access) by the UE may be an NR connection via a gNB composed of a satellite carrying an NTN payload (also simply referred to as a satellite in this specification) and an NTN gateway. Further, the UE may execute procedures for registration with the network and / or establishment of a PDU session via the NR connection, and further, may execute communication using the PDU session established after completion of these procedures.

[0112] Here, in this specification, communication via NTN is also referred to as communication via NR satellite access, or communication via NTN, NTN communication, or satellite communication, etc. Also, an NR connection via NTN is also referred to as NR satellite access, or connection or access via satellite, or satellite access, satellite radio access, etc.

[0113] TN (terrestrial network) may provide terrestrial radio access to the UE through an access network composed of base stations installed on the ground, etc. TN may be a terrestrial network with respect to NTN, which is a non-terrestrial network using satellites. Also, the access network installed and configured on the ground may be, for example, an NG-RAN composed of a plurality of gNBs, or an E-UTRAN composed of a plurality of eNBs, or not limited thereto.

[0114] Here, in this specification, communication via TN is also referred to as communication via NR terrestrial access, or communication via TN, TN communication, or non-satellite communication, etc. Also, an NR connection via TN is also referred to as NR terrestrial access, or connection or access via non-satellite, or non-satellite access, etc.

[0115] The radio access technology (RAT) type of the satellite NG-RAN may be information used to identify or distinguish different types of satellite NG-RAN access in satellite NG-RAN access. Also, the RAT types of the satellite NG-RAN may include, for example, "NR(LEO)", "NR(MEO)", "NR(GEO)", and "NR(OTHERSAT)". Here, "LEO" may mean a low Earth orbit satellite, "MEO" may mean a middle Earth orbit satellite, "GEO" may mean a geostationary Earth orbit satellite, and "OTHERSAT" may mean other satellites, respectively.

[0116] Here, the access technology may be associated with a PLMN or an SNPN. Furthermore, a PLMN or an SNPN may be able to support multiple access technologies. Here, the UE may determine the type of the wireless carrier when selecting a specific PLMN or SNPN using the information of the access technology.

[0117] Also, the AMF may determine the RAT type of the NR satellite access. When the UE is accessing NR using satellite access, an indication indicating the type of the NR satellite access may be provided on the N2 interface. Also, for the implementation of efficient mobility restrictions for NR access, the tracking area (TA) where cells of each NR satellite RAT type are deployed needs to be different from the TAs of other different satellite RAT types and the TAs of the RAT types of terrestrial access. Furthermore, when the AMF receives an N2 UE Context Release Request with a cause value indicating that the UE is not in the PLMN serving area, the AMF may start the deregistration of the UE.

[0118] Here, in this specification, communication via NTN is also referred to as communication via NR satellite access, or communication via satellite access, or 5G SAT communication, or NTN communication, etc. Also, an NR connection via a satellite (i.e., NTN) is also referred to as NR satellite access, or connection or access via a satellite, or satellite access, etc. Also, NR satellite access may be 3GPP access.

[0119] Also, the coverage of NR satellite access provided by a satellite or a satellite constellation may be discontinuous, and such coverage is also referred to as discontinuous network coverage, or discontinuous coverage, or NR satellite access discontinuous coverage. Here, the discontinuous coverage may be due to, for example, the satellite or satellite constellation moving in a time series with respect to a specific location on the earth, resulting in the discontinuous coverage provided by these satellites or satellite constellations.

[0120] Also, a UE connecting to the network via NR satellite access providing such discontinuous coverage is assumed to move in and out of the coverage area in a time series. Therefore, each device of the UE and / or the network may support some or all of one or more functions including control, parameters, or procedures for supporting the discontinuous network coverage provided by NR satellite access. Here, the in-coverage area may mean the coverage (area) where the UE can communicate with the satellite, or the coverage (area) where the UE can communicate via the satellite. Also, the out-of-coverage area may mean the coverage (area) where the UE cannot communicate with the satellite, or the coverage (area) where the UE cannot communicate via the satellite.

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

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

[0123] Also, the AMF may use the satellite coverage availability information to support satellite access by a UE operating in discontinuous coverage. Furthermore, the satellite coverage availability information may be provided from O&M (Operation and Maintenance) to the AMF. Here, the satellite coverage availability information provided to the AMF may describe when and where satellite reception will be possible in a certain area. Also, the satellite coverage availability information is not UE-specific, and the AMF may be applicable to any UE within the area affected. In other words, the satellite coverage availability information may be information on the location or time where the use of satellite access provided by a satellite or a satellite constellation (satellite constellation) by a UE is predicted to be possible. That is, the satellite coverage availability information may be information indicating whether the UE is expected to be within or outside the coverage area at the position and time indicated by the information.

[0124] In addition, the satellite coverage availability information may include, for a terrestrial UE, information indicating, for example, the time and location where each satellite is predicted to be able to provide NR satellite access. Alternatively, the satellite coverage availability information may include, for a terrestrial UE, information indicating the time and location where each satellite is able to provide NR satellite access, and the time and location where each satellite is not able to provide NR satellite access for the terrestrial UE. Note that the terrestrial UE is not intended to mean only a UE that is in strict contact with the earth's surface, and it goes without saying that it also includes a UE that is not in contact with the earth's surface.

[0125] The Unavailability period may be a period or time during which the UE is out of coverage (i.e., outside the coverage area) or is expected or assumed to go out of coverage in non-continuous NR satellite access coverage. Also, the Unavailability period may be synonymous with a UE out-of-coverage period, an Unreachable period, or an Unreachability period. Here, the unavailability period may include an unavailability period due to non-continuous NR satellite access coverage and an unavailability period not due to non-continuous NR satellite access coverage. Further, the unavailability period may be read as an unavailability period due to non-continuous NR satellite access coverage and / or an unavailability period not due to non-continuous NR satellite access coverage. Note that the unavailability period may also be read as the unavailability period duration.

[0126] Also, the unavailability period not due to non - continuous coverage of NR satellite access is a period during which the network (i.e., 5GS) becomes unavailable for, for example, several minutes when the UE performs specific events such as updating the operating system being executed, updating the modem firmware, or silent reset of the modem at any timing as specific events.

[0127] Here, since the application function becomes unavailable without prior notice from the NW and / or the UE during the unavailability period not due to non - continuous coverage of NR satellite access, it may affect the operation of the application server and / or the network that depends on the availability of the UE during this period. Therefore, the UE needs to adjust the unavailability period not due to non - continuous coverage of NR satellite access with the network and / or the application function. Note that the UE and / or the network may send and receive information regarding the unavailability period in order to adjust the unavailability period not due to non - continuous coverage of NR satellite access. Details will be described later.

[0128] Also, here, the unavailability period not due to non - continuous coverage of NR satellite access may be referred to as a conventional function regarding the unavailability period. Note that in this specification, in order to distinguish it from the "support for unavailability period due to non - continuous coverage of NR satellite access" described later, the aforementioned conventional function regarding the unavailability period may be referred to as "support for unavailability period not due to non - continuous coverage of NR satellite access".

[0129] Also, the unavailability period due to non - continuous coverage of NR satellite access is a period during which a UE connected to NR satellite access providing non - continuous coverage goes out of the coverage of NR satellite access and cannot use the network (i.e., 5GS) for, for example, several minutes.

[0130] Here, as information regarding the orbit of the satellite, for example, by considering ephemeris information and the location information of the UE, it is possible to assume in advance whether NR satellite access can provide connectivity to a UE at a specific location on the earth. That is, the UE and / or NW may be able to predict in advance the unavailability period due to non - continuous coverage of NR satellite access from the ephemeris information and the location information of the UE. Incidentally, the UE may receive the ephemeris information as information notified from NR satellite access, and / or as a control message from the network, or as user data.

[0131] Here, in the unavailability period not due to non - continuous coverage of NR satellite access, it is assumed to be the behavior of a specific small number of UEs, and after this period, re - connection to the NW and / or resumption of communication can be carried out again. On the other hand, in the unavailability period due to non - continuous coverage of NR satellite access, when a large number of UEs accommodated in the coverage of the cell provided by NR satellite access become unable to be used during this period and then return to the coverage provided by NR satellite access again, it is assumed that excessive unavailability may occur in the network. For this reason, overload control considering the load caused by the re - connection of a large number of UEs to the NW via NR satellite access after the unavailability period due to non - continuous coverage of NR satellite access is required. Overload control will be described later. Thus, depending on whether the unavailability period is due to non - continuous coverage of NR satellite access or not, the parameters, judgments, behaviors, etc. considered by the UE and / or NW may be different.

[0132] Also, in order to implement the function of such an unavailability period, in order to determine whether the unavailability period is due to non - continuous coverage of NR satellite access, information indicating the type of Unavailability period, and / or Unavailability period duration, and / or the start of unavailability period is required. The following describes these pieces of information.

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

[0134] Note that the support for the unavailability period may include support for the unavailability period due to non - continuous coverage of NR satellite access and support for the unavailability period not due to non - continuous coverage of NR satellite access. Details of specific operations and the like will be described later.

[0135] Information indicating whether the type of Unavailability period is due to non - continuous coverage of NR satellite access and / or not due to non - continuous coverage of NR satellite access. In other words, for example, it may indicate that the type of Unavailability period is due to non - continuous coverage of NR satellite access.

[0136] Unavailability period duration may be information indicating the duration of the unavailability period. Further, the unavailability period duration may be used as a timer value to execute a timer. Here, the unavailability period duration may be information associated with the type of the type of Unavailability period, and the UE and / or NW may transmit or store the association between the type of Unavailability period and the unavailability period duration.

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

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

[0139] Also, for example, the UE out-of-coverage period determined by the network or any network device (e.g., AMF) may be transmitted to the UE or the network or other network devices, and the UE or the network or other network devices may receive and store it. Also, the UE out-of-coverage period is also referred to as the period during which the UE is out of coverage.

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

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

[0142] Also, when the UE determines the UE out-of-coverage period, it may be based on the satellite coverage availability information and UE mobility pattern provided by the network, or the satellite coverage availability information and UE mobility pattern held by the UE. For example, the UE may determine the UE out-of-coverage period based on the satellite coverage availability information provided by the network and the UE mobility pattern provided by the network. Or, for example, the UE may determine the UE out-of-coverage period based on the satellite coverage availability information provided by the network and the UE mobility pattern held by the UE. Or, for example, the UE may determine the UE out-of-coverage period based on the satellite coverage availability information held by the UE and the UE mobility pattern held by the UE, and is not limited thereto.

[0143] Furthermore, for example, if the UE can determine the out-of-UE coverage period and decides to remain in the service-unavailable state during the period indicated by the out-of-UE coverage period, it may execute the Mobility Registration Update procedure before the start of the Unreachability period. Further, the UE may request using the MICO (Mobile Initiated Connection Only) mode parameters considering the out-of-UE coverage period, the eDRX (extended DRX) parameters in CM-IDLE, or other NAS timers for related procedures. In this case, when the UE requests the use of the MICO mode or eDRX, the out-of-UE coverage period is not included. Or, when the UE is about to leave the satellite coverage, it may notify the network of the out-of-UE coverage period and further execute the mobility registration update procedure when it returns to the coverage via any access type.

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

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

[0146] More specifically, for example, in overload control in discontinuous coverage using the maximum waiting time, first, the AMF determines the maximum waiting time based on network settings, or priority users, or priority services, and transmits the maximum waiting time to the UE during the registration procedure or the UE configuration update procedure. Next, if the UE that has received the maximum waiting time has already received the maximum waiting time for the same RAT type and PLMN, the UE may replace the stored or saved maximum waiting time. Further, the UE that has received the maximum waiting time may select a random value with the maximum waiting time as the upper limit and determine a discontinuous coverage wait timer value. In other words, for example, if the UE stores or saves the discontinuous coverage maximum NAS signaling waiting time for each PLMN and / or satellite NG-RAN RAT type, when receiving the discontinuous coverage maximum NAS signaling waiting time for the same combination of PLMN and / or satellite NG-RAN RAT type, it may update to the latest value.

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

[0148] In addition, when the UE returns from outside the coverage area of NR satellite access to inside the coverage area for the same RAT (Radio Access Technology) type and PLMN, the UE starts a discontinuous coverage wait timer. It should be noted that the UE that is executing the discontinuous coverage wait timer shall not start NAS signaling for the RAT type and PLMN. Through the above procedures and processes, a large number of UEs returning to the coverage area can control and reduce the excessive signal load on the network by executing the discontinuous coverage wait timer with different random values respectively.

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

[0150] Also, when the UE stores the maximum NAS signal waiting time for discontinuous coverage due to discontinuous coverage, after coming out of the coverage of the NR satellite access (i.e., out of the circle), when returning to the coverage (i.e., inside the circle), the UE sets the maximum NAS signal waiting time value for discontinuous coverage to a random value up to the maximum NAS signal waiting time for discontinuous coverage stored for this PLMN and satellite NG-RAN RAT type, and starts this timer. During the execution of the maximum NAS signal waiting timer for discontinuous coverage, the UE shall not start the NAS signal on that satellite NG-RAN RAT type and PLMN.

[0151] Furthermore, when the UE receives a paging message, and there is a pending emergency service, or when the UE enters a TAI outside the registered area, the UE may stop the timer according to the maximum NAS signaling waiting time for discontinuous coverage and start the NAS signaling.

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

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

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

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

[0156] The timer offset information in NR satellite access that provides discontinuous coverage is associated with a timer executed while the UE is within the coverage area or a timer executed while the UE is outside the coverage area, and is information indicating the value of the timer offset considering the coverage recognized by the UE or the network based on satellite coverage availability information and the physical coverage gap due to the movement of the UE or the orbit of the satellite, etc. Note that in this specification, the timer offset information in NR satellite access that provides discontinuous coverage may also be referred to as timer offset information indicating time or period, or timer offset information, or timer offset, or offset information, or simply offset, etc.

[0157] Here, the offset information may be information or a parameter pre-configured for the UE, or determined by the UE, or determined by the network. More specifically, for example, the offset information may be information or a parameter pre-configured for the UE. Or, the offset information may be information or a parameter determined by the network, sent to the UE, and stored by the receiving UE. Or, the offset information may be information or a parameter determined by the UE, sent to the network, and stored by the network or each device.

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

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

[0160] Furthermore, when the UE is connected to the network via TN or NTN, particularly via NTN (i.e., NR satellite access), in addition to the conditions for executing the Mobility Registration Update procedure when connecting to the network via the above TN or NTN, the following conditions are considered.

[0161] First, a moving radio cell for NR satellite access may be able to indicate support for one or more TACs per PLMN. Here, a UE registered in a PLMN can access a radio cell as long as at least one supported TAC of the RPLMN or an equivalent RPLMN is part of the UE registration area, and there is no need to execute a mobility registration update procedure. Also, when the UE accesses a radio cell where none of the TACs supported by the RPLMN or an equivalent RPLMN is part of the UE registration area, the UE must execute a mobility registration update procedure.

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

[0163] A serving satellite is a satellite that provides satellite access to the UE. Here, for the serving satellite to provide satellite access to the UE, for example, it may be that the serving satellite provides serving cell(s) to the UE. Also, due to the orbit of the satellite, the serving satellite may cover a predetermined geographical area for a limited period.

[0164] Store and Forward (S&F) Satellite operation refers to an operation mode in which a serving satellite provides communication services (information storage and transfer) to a UE during a period when it is not simultaneously connected to a terrestrial network via a feeder link or an Inter-Satellite Link (ISL), and / or in a geographical area. In the case of an uplink (UL; communication from the UE to the satellite), "store" means storing the UL information from the UE onboard, and "forward" may mean transferring the stored UL information to the terrestrial network. In the case of a downlink (DL; communication from the satellite to the UE), "store" means onboard storage of the DL information from the terrestrial network, and "forward" may mean transferring the stored DL information to the UE.

[0165] Note that in this specification, the communication service provided by the store and forward satellite operation is also referred to as the store and forward function, or store and forward, or S&F function, or communication in the S&F mode, or S&F, etc. Furthermore, a UE, a satellite, and a network that utilize the store and forward function may support the store and forward function.

[0166] UE-Satellite-UE Communication may refer to communication between UEs within the coverage of one or more serving satellites using satellite access without user traffic passing through the terrestrial segment. In other words, UE-Satellite-UE communication may be, for example, communication between two UEs in which the traffic of user data transmitted and received between the UEs does not pass through the terrestrial core network and is transmitted and received via a single satellite or multiple satellites connected by an ISL.

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

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

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

[0170] Here, by the UE indicating the first identification information to the network, the network and each device may recognize that the UE supports communication using the store-and-forward function. Further, the network may execute communication considering that the UE uses the store-and-forward function, or transition to, or activate, a mode of executing communication by the store-and-forward function.

[0171] Also, the details of each behavior of the UE and the NW based on the first identification information will be further described in Chapter 4 and / or Chapter 5.

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

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

[0174] Furthermore, by including the second identification information in the message, the UE may indicate to the network that it supports the store-and-forward function and / or requests or prioritizes communication using the store-and-forward function.

[0175] Also, the details of the behaviors of the UE and the NW based on the second identification information will be further described in Chapter 4 and / or Chapter 5.

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

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

[0178] Also, the third identification information may be the identification information included by the UE in the message when the UE supports store-and-forward. And / or, the third identification information may be the identification information included by the UE in the message when the UE includes the first identification information indicating store-and-forward in the message. And / or, when the UE includes information indicating that it prioritizes store-and-forward in the message, even if the UE does not include the first information in the message, the network may recognize that the UE supports the store-and-forward function. And / or, combining the first identification information and the second identification information may indicate that the UE supports the store-and-forward function. In this specification, unless otherwise specified, the UE may support the store-and-forward function and / or may be information indicating the preference for using the store-and-forward function.

[0179] Note that the third identification information may be the same as or different from the content of the fifth identification information described later. More specifically, for example, the number and content of the S-NSSAI indicated by the third identification information may be the same as or different from the number and content of the S-NSSAI indicated by the fifth identification information, or the content of some one or more S-NSSAI indicated by the third identification information and the fifth identification information may be the same, and so on.

[0180] Further, the details of the behaviors of the UE and the NW based on the third identification information will be further described in Chapter 4 and / or Chapter 5.

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

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

[0183] Here, by the NW indicating the fourth identification information to the network, the UE may recognize that the NW supports communication using the store-and-forward function. Further, the UE that has received the fourth identification information from the NW may also recognize that communication using the store-and-forward function is possible. Further, the UE may execute communication considering that the NW uses the store-and-forward function, or transition to or activate a mode for executing communication by the store-and-forward function.

[0184] Further, the details of the behaviors of the UE and the NW based on the fourth identification information will be further described in Chapter 4 and / or Chapter 5.

[0185] The fifth identification information in this embodiment may be an NSSAI including one or more S-NSSAIs that support store-and-forward shown by the NW to the UE, or an S-NSSAI that supports the store-and-forward function. Here, the PDU session established for the S-NSSAI that supports the store-and-forward function may be an S-NSSAI capable of communicating using the store-and-forward function.

[0186] Also, here, when the NW indicates a network slice (S-NSSAI) that supports the store-and-forward function to the UE, a message including the fifth identification information may be transmitted to the UE. More specifically, for example, the NW may indicate a network slice (S-NSSAI) that supports the store-and-forward function to the UE by including the fifth identification information in the allowed NSSAI in the registration acceptance message, or by including the second identification information as the allowed NSSAI in the registration acceptance message.

[0187] Note that the fifth identification information may be the same as or different from the third identification information described later. More specifically, for example, the number and content of the S-NSSAIs indicated by the third identification information may be the same as or different from the number and content of the S-NSSAIs indicated by the fifth identification information, or the content of some one or more S-NSSAIs indicated by the third identification information and the fifth identification information may be the same, and so on.

[0188] Also, the details of the behaviors of the UE and the NW based on the fifth identification information will be further described in Chapter 4 and / or Chapter 5.

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

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

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

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

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

[0194] In addition, here, the UE that receives the message including the seventh identification information may replace or update the SM timer value already stored or pre-configured in the UE, or store it as the value of the SM timer for communication using the store-and-forward function different from the normal SM timer value already stored, or update the value of the SM timer for communication using the store-and-forward function different from the normal SM timer value pre-configured in the UE. Also, when a UE that does not support the store-and-forward function receives a message including the seventh identification information from the network, the UE ignores the seventh identification information.

[0195] In addition, the conventional SM timer and the conventional SM timer value may be the SM timer and the SM timer value used in communication without using the store-and-forward function.

[0196] Furthermore, the details of the behaviors of the UE and the NW based on the seventh identification information will be further described in Chapter 4 and / or Chapter 5.

[0197] The above first to seventh identification information may be included in the message as individual identification information, or may be included in the message as one piece of information combining one or more of them. Also, one piece of information combining one or more of the first to seventh identification information may mean a combination of matters indicated by the identification information described in this chapter. In other words, when a plurality of identification information is transmitted and received, two or more of these identification information may be configured as one or more pieces of identification information. Note that the information indicating the support of each function and the information indicating the requirement for the use of each function may be transmitted and received as the same identification information, or may be transmitted and received as different identification information.

[0198] The details of the behaviors of the UE and the network based on one or a combination of the above first to seventh identification information are not limited to those described in this chapter, and will be further described in Chapter 4 and / or Chapter 5.

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

[0200] Furthermore, in each embodiment, as described in FIG. 2, the case where the HSS and UDM, the PCF and PCRF, the SMF and PGW-C, and the UPF and PGW-U are each configured as the same device (i.e., the same physical hardware, or the same logical hardware, or the same software) will be taken as an example for explanation. However, the content described in this embodiment is also applicable when these are configured as different devices (i.e., different physical hardware, or different logical hardware, or different software). For example, direct data transmission and reception may be performed between them, or data may be transmitted and received via the N26 interface between the AMF and MME, or data may be transmitted and received via the UE.

[0201] The following describes the details of the registration procedure.

[0202] [4.1. Registration Procedure] First, the registration procedure will be described with reference to FIG. 6. The registration procedure is a procedure in 5GS. Hereinafter, in this section, this procedure refers to the registration procedure. The registration procedure is a procedure for the UE to register with the access network_B, and / or the core network_B, and / or the DN. If the UE is not registered with the network, for example, it can execute this procedure at any timing such as when the power is turned on. In other words, if the UE is in the non-registered state (RM-DEREGISTERED state), it can start this procedure at any timing. Also, each device (especially the UE and the AMF) can transition to the registered state (RM-REGISTERED state) based on the completion of the registration procedure.

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

[0204] Furthermore, the registration procedure may be a procedure for updating the location registration information of the UE in the network and / or for periodically notifying the network of the UE's state from the UE and / or for updating specific parameters related to the UE in the network. Or, this procedure may be a Mobility Registration Update procedure executed to resume normal services after the unavailability period has ended after the completion of the initial registration procedure.

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

[0206] When the UE performs mobility across TAs, it may initiate the registration procedure. More specifically, when the UE moves to a TA different from the TA indicated in the TA list it holds, it may initiate the Mobility Registration Update procedure for re-registration. Further, the UE may initiate this procedure when the timer it is running expires. Further, the UE may initiate the registration procedure when the context of each device needs to be updated due to the disconnection or invalidation of a PDU session. Further, the UE may initiate the registration procedure when there is a change in the capability information and / or preferences regarding the establishment of the UE's PDU session. Further, the UE may initiate the registration procedure periodically. Further, the UE may initiate the registration procedure based on the completion of the UE configuration update procedure. Note that the UE is not limited to these and can execute the registration procedure at any timing.

[0207] Furthermore, even when in a registered state, the UE may periodically initiate the registration procedure. In other words, the UE may initiate the registration procedure based on the expiration of a timer. In other words, the registration procedure that is executed periodically may be a Periodic Registration Update procedure.

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

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

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

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

[0212] Also, when a plurality of identification information is transmitted and received, two or more pieces of this identification information may be configured as one or more pieces of identification information. Note that information indicating support for each function and information indicating a request for use of each function may be transmitted and received as the same identification information or as different identification information.

[0213] Also, the UE may start a PDU session establishment procedure during the registration procedure by including an SM message in the registration request message and transmitting it, or by transmitting an SM message together with the registration request message. Here, the SM message may be a PDU session establishment request message.

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

[0215] The AMF that has received the registration request message from the UE may recognize and store what the identification information included in the registration request message means.

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

[0217] Still, the first condition determination may be executed based on the reception of a registration request message, and / or each piece of identification information included in the registration request message, and / or subscriber information, and / or network capability information, and / or operator policy, and / or network status, and / or user registration information, and / or context held by the AMF, etc. For example, when the network permits the UE's request, the first condition determination is true, and when the network does not permit the UE's request, the first condition determination may be false. Also, when the network to which the UE is registered and / or a device in the network supports the function requested by the UE, the first condition determination is true, and when the function requested by the UE is not supported, the first condition determination may be false. Furthermore, when the transmitted and received identification information is permitted, the first condition determination is true, and when the transmitted and received identification information is not permitted, the first condition determination may be false. Note that the conditions for determining the truth or falsehood of the first condition determination may not be limited to the conditions described above.

[0218] First, the case where the first condition determination is true will be described. In the procedure of FIG. 6(A), the AMF can first execute the fourth condition determination. The fourth condition determination is for determining whether the AMF performs transmission and reception of SM messages with the SMF.

[0219] Note that the fourth condition determination may be executed based on whether the AMF has received an SM message. Also, the fourth condition determination may be executed based on whether an SM message is included in the registration request message. For example, when the AMF has received an SM message and / or when an SM message is included in the registration request message, the fourth condition determination may be true, and when the AMF has not received an SM message and / or when an SM message is not included in the registration request message, the fourth condition determination may be false. Note that the conditions for determining the truth or falsehood of the fourth condition determination may not be limited to the conditions described above.

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

[0221] The AMF may include any one or more of the fourth to seventh identification information in the Registration accept message and transmit it.

[0222] Also, when a plurality of identification information is transmitted and received, two or more of these identification information may be configured as one or more identification information. Note that the information indicating the support of each function and the information indicating the requirements for the use of each function may be transmitted and received as the same identification information or as different identification information.

[0223] Note that whether to include any one or more of the fourth to seventh identification information in the Registration accept message may be selected and determined based on each identification information received by the AMF from the UE or each device, and / or subscriber information, and / or network capability information, and / or operator policy, and / or network state, and / or user registration information, and / or the context held by the AMF, etc.

[0224] In addition, the AMF can send the SM message included in the registration acceptance message or send the SM message together with the registration acceptance message. However, this sending method may be executed when the SM message is included in the registration request message and the fourth condition determination is true. Also, this sending method may be executed when the SM message is included together with the registration request message and the fourth condition determination is true. By performing such a sending method, the AMF can indicate that the procedure for SM has been accepted in the registration procedure. Here, the SM message may be a PDU session establishment request message or a PDU session establishment acceptance message.

[0225] In addition, based on each received identification information, and / or subscriber information, and / or network capability information, and / or operator policy, and / or network status, and / or user registration information, and / or context held by the AMF, etc., the AMF may indicate that the UE's request has been accepted by sending a registration acceptance message.

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

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

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

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

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

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

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

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

[0234] Note that the procedure of (B) in FIG. 6 may also be started when the procedure of (A) in FIG. 6 is aborted.

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

[0236] Also, the UE may complete the registration procedure based on the reception of a registration acceptance message or a registration rejection message.

[0237] Furthermore, each device may perform processing based on the information transmitted and received in the registration procedure based on the completion of the registration procedure. For example, when information indicating that some requests of the UE have been rejected is transmitted and received, the reason for the rejection of the UE's request may be recognized. Furthermore, each device may perform this procedure again based on the reason for the rejection of the UE's request, or may perform a registration procedure for the core network_B or another cell.

[0238] Furthermore, based on the completion of the registration procedure, the UE may store the identification information received together with the registration acceptance message and / or the registration rejection message, or may recognize the decision of the network.

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

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

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

[0242] Here, the session management procedure may include a PDU session establishment procedure, a PDU session modification procedure, a PDU session release procedure, or a PDU session authentication and authorization procedure.

[0243] In addition, these session management procedures may include procedures initiated at the request of the UE (UE-requested) and procedures initiated at the request of the network (NW-requested). Here, in this specification, procedures initiated at the request of the network are also referred to as Network initiated (NW-init) procedures, and procedures initiated at the request of the UE are also referred to as UE initiated (UE-init) procedures.

[0244] Here, more specifically, for example, the PDU session establishment procedure may only include UE-requested procedures. Also, for example, each of the PDU session modification procedure or the PDU session release procedure may include UE-requested procedures and NW-requested procedures. Also, for example, the PDU session authentication and authorization procedure may only include NW-requested procedures.

[0245] Furthermore, the UE-requested PDU session modification procedure or the UE-requested PDU session release procedure may start each procedure by the UE sending a request message, and subsequently, the execution of the network-requested PDU session modification procedure or the network-requested PDU session release procedure, or the execution or completion of each procedure by the transmission of a response message from the NW to the UE (e.g., a rejection message) will be described in detail later.

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

[0247] Further, the process (A) in the session management procedure described in FIG. 7 may be a process that is only executed in the UE-requested PDU session change procedure and the UE-requested PDU session release procedure. In other words, in the PDU session establishment procedure or the PDU session authentication and authorization procedure, the process (A) in the session management procedure described in FIG. 7 may not be executed, and only the transmission of the session management request message from the UE to the SMF (S700) and the transmission of the session management request message from the SMF to the UE may be executed.

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

[0249] Subsequently, each step of the session management procedure will be described.

[0250] First, the UE transmits a session management request message to the core network (S700). More specifically, the UE transmits a session management request message (also referred to as an SM request message) to the SMF via the gNB ((R)AN) and the AMF. Also, by the UE transmitting the session management request message to the network, the UE-requested session management procedure may be started.

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

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

[0253] Next, the SMF that has received the session management request message from the UE may execute the process of (A) or execute the transmission of the response message to the session management request to the UE (S706).

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

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

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

[0257] Here, in the network-requested PDU session modification procedure and the network-requested PDU session modification procedure, upon receiving the response message corresponding to the Command from the UE, the session management procedure is completed or terminated, and the subsequent procedures described in FIG. 7 do not need to be executed.

[0258] Alternatively, when the SMF responds to the session management request message received from the UE, or when rejecting the response from the UE in each procedure or each procedure without executing the process of (A), the SMF sends a response message (also referred to as an SM response message) for the session management request message to the UE (S706). More specifically, for example, in the PDU session establishment procedure, when the SMF receives a PDU session establishment request message from the UE (S700), the SMF may send a PDU session establishment acceptance message or a PDU session establishment rejection message to the UE (S706). Note that in the PDU session establishment procedure, the process of (A) does not need to be performed.

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

[0260] Here, if the UE does not receive a command message or a response message to a session management request from the network (i.e., the SMF) before the expiration of the SM timer started with the transmission of various session management request messages, the UE may retransmit the session management request message. Furthermore, the UE can repeat the transmission of the SM request message, the start, and the expiration of the SM timer up to 5 times. When the 5th SM timer expires, the UE aborts various SM procedures.

[0261] Also, here, if the SMF does not receive a response to the command message from the UE before the expiration of the SM timer started with the transmission of various command messages, the SMF may retransmit the command message. Furthermore, the SMF can repeat the transmission of the command message, the start, and the expiration of the SM timer up to 5 times. When the 5th SM timer expires, the SMF aborts various SM procedures.

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

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

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

[0265] Furthermore, the UE may stop the T3580 timer based on the reception of the PDU session establishment rejection or acceptance message from the SMF. Here, if the UE does not receive the PDU session establishment rejection or acceptance message by the expiration of T3580, the UE may transmit a PDU session establishment request message to the SMF again. Furthermore, the expiration of T3580 and the retransmission of the PDU session establishment request message may be executed 4 times, and based on the 5th expiration of the timer T3580, the UE may terminate the PDU session establishment procedure.

[0266] As described above, here, as a specific example of the session management procedure, a specific example of the PDU session establishment procedure has been described. However, other SM procedures may also operate according to the description in this chapter, and each message transmitted and received in the procedure of this embodiment may be read as the message name, timer, and timer value of each procedure of other SMs.

[0267] As described above, in this chapter, the transmission and reception of messages of each device of the conventional UE and network that do not use the store-and-forward function and the processing of the session management timer in the session management procedure of the UE request and the network request have been described.

[0268] Details and examples of the session management procedure considering the use of the store-and-forward function will be described in Chapter 5.

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

[0270] Also, each embodiment may be an embodiment that starts when the UE is connected to the network via NR satellite access and the registration is complete. Furthermore, each embodiment may be a state in which each device of the UE and the network and the satellite support the store-and-forward function, and communication via the control plane and / or communication via the user plane using the store-and-forward function are possible.

[0271] In other words, each of these embodiments starts in a state where the UE transmits a registration request message including any one or more of the first to third identification information indicating that the UE supports the store-and-forward function or requests or prioritizes the store-and-forward function in the initial registration procedure or the registration update procedure, and receives a registration acceptance message including any one or more of the fourth to seventh identification information indicating that the network supports the store-and-forward function or uses the store-and-forward function.

[0272] The objective of each embodiment described in this chapter is to solve the problems in executing conventional processing that does not consider the store-and-forward function in the session management procedure when the UE, satellite, and core network support the store-and-forward function. More specifically, for example, in a situation where the service link is valid but the feeder link is not valid, in the SM procedure executed by each device of the UE and / or the network, an embodiment is shown that aims to solve the problem so that the procedure is not aborted when the message transmission by the UE and the expiration of the SM timer are repeated 5 times. Conversely, for example, in a situation where the feeder link is valid but the service link is not valid, in the SM procedure executed by each device of the UE and / or the network, an embodiment is shown that aims to solve the problem so that the procedure is not aborted when the message transmission by the network and the expiration of the SM timer are repeated 5 times.

[0273] Also, the embodiments in this example are not limited to individually and independently executing each embodiment described in each section of this chapter without special notice, and may be implemented as a combination of one or more embodiments described in each section, or one or more embodiments described in each section may be executed in any order.

[0274] Hereinafter, each embodiment of the example will be described.

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

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

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

[0278] Subsequently, in the PDU session establishment procedure requested and started by the UE, a PDU session establishment request message is sent. Along with the sending of the PDU session establishment request message, a timer T3580 is started as an SM timer. The timer value of the timer T3580 may be a value used in communication considering the store-and-forward function and using the store-and-forward function. Further, based on the reception of the sixth identification information, the UE may set and execute a timer value considering the store-and-forward function for the timer T3580.

[0279] Here, the timer value of the timer T3580 considering the store-and-forward function may be a value different from the value of the conventional timer T3580 used in communication without considering the store-and-forward function, and may also be a value longer than the conventional timer T3580. Here, the value of the timer T3580 considering the store-and-forward function may be the seventh identification information included in the registration acceptance message received by the UE from the network.

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

[0281] Furthermore, when the UE receives the seventh identification information including the new timer value of the timer T3580 considering the store-and-forward function while already storing the timer value of the timer T3580 considering the store-and-forward function, the UE may replace the stored timer value with the new timer value, or set the new timer value for the timer T3580, or replace the timer value already set for the timer T3580 with the new timer value. Here, the UE may receive a registration acceptance message including the seventh identification information together with the sixth identification information. Also, when the timer value of the seventh identification information received by the UE is "0", the UE may erase the timer value of the timer T3580 considering the store-and-forward function that it has stored.

[0282] Also, the timer value considering the store-and-forward function may be set in consideration of the time when the feeder link becomes effective or recovers during the transmission of the session management request message by the UE and the execution of the SM timer up to 5 times with the timer value considering the store-and-forward function.

[0283] As described above, an example in the case where the session management procedure executed by the UE after the registration procedure is mainly the PDU session establishment procedure has been explained. However, the same processing may be performed in the PDU session change procedure or PDU session release procedure requested by the UE or the network, or the PDU session authentication and authorization procedure requested by the network.

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

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

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

[0287] Subsequently, in the PDU session establishment procedure requested and started by the UE, even when the transmission of the PDU session establishment request message and the repetition of the start and expiration of the timer T3580 associated with the transmission of the PDU session establishment request message exceed 5 times, the PDU session establishment procedure is not aborted, and it may be repeated more than 5 times until a PDU session establishment acceptance message or a PDU session request message is received as a response message to the session management request message from the network.

[0288] In other words, for example, the UE may further transmit a PDU session establishment request message at the timing when the timer T3580 expires for the fifth time, and start the timer T3580 in association with the transmission. Further, the UE does not have to transition to the "PROCEDURE TRANSACTION INACTIVE state" as the timer T3580 expires for the fifth time.

[0289] According to this embodiment, considering the store-and-forward function, until the feeder link becomes effective or recovers, by repeating the transmission of session management messages, and the start and expiration of the timer, the present invention provides the processing of each device of the UE and / or the network for completing the SM procedure without aborting it.

[0290] As described above, as an example of the session management procedure executed by the UE after the registration procedure, the case mainly being the PDU session establishment procedure has been described. However, the PDU session change procedure or PDU session release procedure required by the UE or the network, or the PDU session authentication and authorization procedure required by the network may be processed in the same manner.

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

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

[0293] Further, this embodiment may be an embodiment that further considers a network slice supporting a store-and-forward function for each behavior of the UE and / or the network described in the first embodiment or the second embodiment.

[0294] More specifically, the UE of this embodiment includes, for example, first identification information as capability information indicating that the UE supports a store-and-forward function and / or second identification information indicating a network slice (S-NSSAI) supporting one or more store-and-forward functions in a registration request message and transmits it to the network, and receives a registration acceptance message including sixth identification information indicating that at least the store-and-forward function is to be used and / or fifth identification information indicating a network slice supporting one or more store-and-forward functions from the network, thereby completing the registration procedure. Here, the fifth identification information may be an allowed NSSAI including an S-NSSAI that supports communication by one or more store-and-forward functions.

[0295] Subsequently, when the UE executes a PDU session establishment procedure for an S-NSSAI that supports the store-and-forward function included in the allowed NSSAI requested and started by the UE, the UE starts a timer T3580 in association with the transmission of a PDU session establishment request message based on the sixth identification information. Here, the timer value of the timer T3580 may be a timer value that takes the store-and-forward function into account and is used in communication using the store-and-forward function. Further, the UE may set and execute a timer value of the timer T3580 that takes the store-and-forward function into account based on the reception of the sixth identification information. Here, the timer value and the behavior of each device of the related UE and / or network may be equivalent to the timer value described in the first embodiment, and detailed description thereof is omitted.

[0296] Alternatively, more specifically, the UE of this embodiment may include, in a registration request message, first identification information as capability information indicating that the UE supports a store-and-forward function, and / or second identification information indicating a network slice (S-NSSAI) that supports one or more store-and-forward functions, and send the message to the network. The UE may complete the registration procedure by receiving a registration acceptance message from the network that includes sixth identification information indicating that at least the store-and-forward function is to be used, and / or fifth identification information indicating a network slice that supports one or more store-and-forward functions. Here, the fifth identification information may be an allowed NSSAI that includes an S-NSSAI that supports communication using one or more store-and-forward functions.

[0297] Subsequently, when the UE executes a PDU session establishment procedure for an S-NSSAI that supports the store-and-forward function included in the allowed NSSAI requested and started by the UE, the UE sends a PDU session establishment request message and starts a timer T3580 associated with the transmission of the PDU session establishment request message. Here, based on the reception of the sixth identification information, the timer value of the timer T3580 started by the UE may be a value used in communication using the store-and-forward function, taking the store-and-forward function into account. Further, here, even when the transmission of the PDU session establishment request message, and the repetition of starting and expiring of the timer T3580 exceed five times, the UE does not abort the PDU session establishment procedure, and may repeat more than five times until receiving a PDU session establishment acceptance message or a PDU session request message as a response message to the session management request message from the network. Here, the behavior of each device of the UE and / or the network regarding the retransmission of more than five SM messages and the SM timer may be equivalent to the timer values described in the second embodiment, and a detailed description thereof is omitted.

[0298] As described above, as an example of the session management procedure that the UE executes after the registration procedure, the PDU session establishment procedure has been mainly described. However, the PDU session change procedure or PDU session release procedure required by the UE or the network, or the PDU session authentication and authorization procedure required by the network may be similarly processed.

[0299] [5.4. Fourth Embodiment] The fourth embodiment in this example will be described. In this section, the fourth embodiment is also referred to as this embodiment.

[0300] This embodiment relates to the NW's processing regarding that when the NW recognizes that each device of the UE, satellite, and network can communicate using the store-and-forward function, even if the UE is in the unavailability period due to discontinuous satellite coverage, the NW can start the SM procedure required by the network.

[0301] Furthermore, this embodiment relates to the behavior of the network in the SM procedure required by the network, which is executed when each device of the UE, satellite, and network supports the store-and-forward function, and furthermore, the feeder link is valid but the service link is not valid.

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

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

[0304] Subsequently, regarding the PDU session change procedure, PDU session release procedure, or PDU session authentication and authorization procedure required by the network and executed by the SMF, it may be the same as each behavior and process described in the first to third embodiments. In other words, the behavior of the SMF of the present embodiment may be the same as other behaviors, for example, by reading the UE as the SMF. More specifically, regarding the value of the SM timer, and / or the retransmission of the SM message and the number of times the SM timer expires, and / or the number of retransmissions of the SM message considering the network slice supporting the store-and-forward function and the value of the SM timer, and / or the retransmission of the SM message and the number of times the SM timer expires considering the network slice supporting the store-and-forward function, each behavior and process on the SMF side may be the same as that on the UE side.

[0305] [5.5. Fifth Embodiment] The fifth embodiment in this example will be described. In this section, the fifth embodiment is also referred to as the present embodiment.

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

[0307] After the completion of the registration procedure, the UE of the present embodiment may execute the PDU session establishment procedure required by the UE in the same manner as in the first to third embodiments. Here, the UE may send a PDU session establishment request message, and when the start and expiration of the SM timer T3580 associated with the transmission occur five times, the UE may abort the PDU session establishment procedure and transition to the "PROCEDURE TRANSACTION INACTIVE state". Here, when the UE that has transitioned to the "PROCEDURE TRANSACTION INACTIVE state" receives a PDU session establishment acceptance message from the network, the UE may recognize that the PDU session has been established. In other words, the UE that is performing communication using the store-and-forward function may retain the context regarding the PDU session establishment procedure without erasing it even after transitioning to the "PROCEDURE TRANSACTION INACTIVE state".

[0308] As described above, an example where the session management procedure executed by the UE after the registration procedure is mainly the PDU session establishment procedure has been explained. However, the same processing may be performed in the PDU session modification procedure or PDU session release procedure required by the UE or the network, or the PDU session authentication and authorization procedure required by the network. [6. Variation] The program that operates in the apparatus according to an aspect of the present embodiment may be a program that controls a Central Processing Unit (CPU) or the like to make a computer function so as to realize the functions of the embodiment according to an aspect of the present embodiment. The program or the information handled by the program may be 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.

[0309] Furthermore, a program for realizing the functions of the embodiments according to one aspect of the present embodiment 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 in 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.

[0310] In addition, each functional block or various features of the device 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 may be a conventional type processor, controller, microcontroller, or 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 embodiment can also use a new integrated circuit by such technology.

[0311] Note that the present embodiment is not limited to the above-described embodiments. In the embodiments, an example of the device is described, but the present embodiment is not limited thereto, and it can 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 household appliances.

[0312] As described above in detail with reference to the drawings regarding the embodiments of this example, the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of this example are also included. Also, this example 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 this example. Further, a configuration in which elements described in the above embodiments and elements having the same effects are replaced with each other is also included.

Description of Reference Numerals

[0313] 1 Mobile communication system 10 UE_A 30 PGW-U 32 PGW-C 35 SGW 40 MME 45 eNB 50 HSS 60 PCRF 80 Access network_A (E-UTRAN) 90 Core network_A 120 Access network_B (5G AN) 122 gNB 130 UPF 132 SMF 140 AMF 150 UDM 160 PCF 190 Core network_B 235 UPF_A 239 UPF_C

Claims

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

2. The transceiver unit transmits the PDU session establishment request message at the timing when the first timer expires 5 times, and the control unit starts the first timer at the timing when the PDU session establishment request message is transmitted. The UE according to claim 1, characterized by the above.

3. A UE (User Equipment) comprising a transceiver unit and a control unit, wherein the transceiver unit, transmits to the network the capability information indicating that the UE supports the store-and-forward function and one or more S-NSSAIs (Single Network Slice Selection Assistance Information) supporting communication by the store-and-forward function, included in the requested NSSAI (Network Slice Selection Assistance Information), receives from the network the first information indicating that the network uses the store-and-forward function and an allowed NSSAI including one or more S-NSSAIs supporting communication by the store-and-forward function, when the UE executes a PDU (Protocol Data Unit) session establishment procedure for an S-NSSAI supporting the store-and-forward function included in the allowed NSSAI. Based on the first information, even when the repetition of the transmission of the PDU session establishment request message by the transmission / reception unit, the start and expiration of the first timer associated with the transmission of the PDU session establishment request message, becomes five or more times, the control unit does not abort the PDU session establishment procedure and repeats until a response message is received from the network. UE characterized by the above.

Images