UE, and Communication Control Method

Abstract

Provided is a communication control method which, when a UE receives a congestion management reason value and a back-off timer value in a state in which network slice information associated with an established PDU session has the potential of being updated, realizes congestion management by using a back-off timer associated with network slice information that the UE has transmitted to a device within a core network and network slice information that the UE has received from a device within a core network, in the state in which the network slice information associated with the established PDU session has the potential of being updated.

Description

Technical Field

[0001] This application relates to a UE and a communication control method. This application claims the benefit of priority with respect to Japanese Patent Application No. 2019-236463, filed on December 26, 2019, and by reference thereto, the entire contents thereof are incorporated herein.

Background Art

[0002] 3GPP (3rd Generation Partnership Project), which conducts standardization activities for recent mobile communication systems, is studying SAE (System Architecture Evolution), which is the system architecture of LTE (Long Term Evolution). 3GPP is standardizing EPS (Evolved Packet System) as a communication system that realizes all-IP (Internet Protocol). The core network constituting EPS is called EPC (Evolved Packet Core).

[0003] In recent years, 3GPP has also been studying next-generation communication technologies and system architectures for the 5G (5th Generation) mobile communication system, which is the next-generation mobile communication system. In particular, as a system for realizing the 5G mobile communication system, it is standardizing 5GS (5G System) (see Non-Patent Document 1 and Non-Patent Document 2). In 5GS, technical issues for connecting various types of terminals to a cellular network are extracted, and solutions are standardized.

[0004] For example, optimization and diversification of communication procedures for supporting continuous mobile communication services according to terminals that support various access networks, and optimization of the system architecture in accordance with the optimization and diversification of communication procedures are also cited as requirements.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] In 5GS, in addition to a mechanism that provides a function corresponding to congestion management, control signal management based on reasons other than congestion management is also being studied (see Non-Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3).

[0007] Furthermore, in 5GS, when a UE changes the PLMN, a technique for updating the network slice information associated with the established PDU session is also under consideration.

[0008] However, in a state where the network slice information associated with the established PDU session may be updated, a method for realizing congestion management has not been clarified.

[0009] The present invention has been made in view of such circumstances, and its object is to provide a mechanism and a communication control method for realizing congestion management in a state where the network slice information associated with a PDU session may be updated.

Means for Solving the Problems

[0010] The UE (User Equipment; terminal device) of the present invention includes a transmission / reception unit that transmits a PDU (Protocol Data Unit) session establishment request message to a control device and receives a PDU session establishment acceptance message including a PDU session ID and a first S-NSSAI (Single Network Slice Selection Assistance information) from the control device, and receives a PDU session change rejection message including the PDU session ID from the control device, and a control unit that starts a backoff timer based on the reception of the PDU session change rejection message. When no S-NSSAI and a DNN (Data Network Name) are provided by the UE together with the PDU session establishment request message, the backoff timer is associated with no S-NSSAI, the first S-NSSAI, and the DNN. When no S-NSSAI and no DNN are provided by the UE together with the PDU session establishment request message, the backoff timer is associated with no S-NSSAI, the first S-NSSAI, and no DNN.

[0011] The communication control method of the UE (User Equipment) of the present invention includes: transmitting a PDU (Protocol Data Unit) session establishment request message to a control device; receiving, from the control device, a PDU session establishment acceptance message including a PDU session ID and a first S-NSSAI (Single Network Slice Selection Assistance information); receiving, from the control device, the PDU session ID and a PDU session change rejection message; and starting a backoff timer based on the reception of the PDU session change rejection message. When no S-NSSAI and a DNN (Data Network Name) are provided by the UE together with the PDU session establishment request message, the backoff timer is associated with no S-NSSAI, the first S-NSSAI, and the DNN. When no S-NSSAI and no DNN are provided by the UE together with the PDU session establishment request message, the backoff timer is associated with no S-NSSAI, the first S-NSSAI, and no DNN. This is the gist of the invention.

Advantages of the Invention

[0012] According to one aspect of the present invention, a terminal device or a device in a core network that constitutes 5GS performs management processes such as congestion management for each network slice and / or DNN even in a state where the network slice information associated with a PDU session may be updated. This is the gist of the invention.

Brief Description of the Drawings

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[0014] Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. In this embodiment, as an example, an embodiment of a mobile communication system when the present invention is applied will be described.

[0015] [1. System Overview] The outline of the mobile communication system will be described with reference to FIGS. 1, 2, 3, and 4. FIG. 2 is a diagram showing the details of the access network in the mobile communication system of FIG. 1. FIG. 3 is a diagram showing the details of the core network_A90 mainly in the mobile communication system of FIG. 1. FIG. 4 is a diagram showing the details of the core network_B190 mainly in the mobile communication system of FIG. 1. As shown in FIG. 1, the mobile communication system 1 is composed of a terminal device (also referred to as a user device or a mobile terminal device) UE (User Equipment)_A10, an access network (AN; Access Network)_A, an access network_B, a core network (CN; Core Network)_A90, a core network_B190, a packet data network (PDN; Packet Data Network)_A6, and a data network (DN; Data Network)_A5. Incidentally, the combination of the access network_A and the core network_A90 may be referred to as EPS (Evolved Packet System; 4G mobile communication system), the combination of the access network_B, the core network_B190, and the UE_A10 may be referred to as 5GS (5G System; 5G mobile communication system), and the configurations of 5GS and EPS are not limited to these. For simplicity, the core network_A90, the core network B, or a combination thereof may sometimes be referred to as the core network, the access network_A, the access network_B, or a combination thereof may sometimes be referred to as the access network or the radio access network, and the DN_A5, the PDN_A6, or a combination thereof may sometimes be referred to as the DN.

[0016] Here, UE_A10 may be a device that can be connected to network services via 3GPP access (also referred to as 3GPP access network) and / or non-3GPP access (also referred to as non-3GPP access network). Also, UE_A10 may be equipped with a UICC (Universal Integrated Circuit Card) or an eUICC (Embedded UICC). Further, UE_A10 may be a wirelessly connectable terminal device, such as a ME (Mobile Equipment), an MS (Mobile Station), or a CIoT (Cellular Internet of Things) terminal (CIoT UE).

[0017] Also, UE_A10 can be connected to an access network and / or a core network. Further, UE_A10 can be connected to DN_A and / or PDN_A via the access network and / or the core network. UE_A10 transmits and receives (communicates) user data using a PDU (Protocol Data Unit or Packet Data Unit) session and / or a PDN (Packet Data Network) connection (also referred to as a PDN connection) between DN_A and / or PDN_A. Moreover, the communication of user data is not limited to IP (Internet Protocol) communication (IPv4 or IPv6). For example, in EPS, it may be non-IP communication, and in 5GS, it may be Ethernet (registered trademark) communication or Unstructured communication.

[0018] Here, IP communication refers to data communication using IP, which is realized by transmitting and receiving IP packets with an IP header attached. Note that the payload part constituting the IP packet may include user data transmitted and received by UE_A10. Also, non-IP communication refers to data communication without using IP, which is realized by transmitting and receiving data without an IP header attached. For example, non-IP communication may be data communication realized by transmitting and receiving application data without an IP address assigned, or may transmit and receive user data transmitted and received by UE_A10 with another header such as a MAC header or an Ethernet (registered trademark) frame header attached.

[0019] Also, a PDU session is a connectivity established between UE_A10 and DN_A5 to provide a PDU connection service. More specifically, the PDU session may be a connectivity established between UE_A10 and an external gateway. Here, the external gateway may be a UPF, a PGW (Packet Data Network Gateway), or the like. Also, the PDU session may be a communication path established to transmit and receive user data between UE_A10 and the core network and / or DN, or may be a communication path for transmitting and receiving PDUs. Furthermore, the PDU session may be a session established between UE_A10 and the core network and / or DN, or may be a logical communication path composed of one or more bearers or the like between each device in the mobile communication system 1. More specifically, the PDU session may be a connection established by UE_A10 between the core network_B190 and / or an external gateway, or may be a connection established between UE_A10 and a UPF. Also, the PDU session may be a connectivity and / or connection between UE_A10 and UPF_A235 via the NR node_A122. Furthermore, the PDU session may be identified by a PDU session ID and / or an EPS bearer ID.

[0020] Furthermore, UE_A10 can execute transmission and reception of user data using a PDU session with a device such as an application server disposed in DN_A5. In other words, the PDU session can transfer user data transmitted and received between UE_A10 and a device such as an application server disposed in DN_A5. Further, each device (UE_A10, a device in the access network, and / or a device in the core network, and / or a device in the data network) may manage by associating one or more pieces of identification information with the PDU session. Note that these pieces of identification information may include at least one of an APN (Access Point Name), a TFT (Traffic Flow Template), a session type, application identification information, identification information of DN_A5, NSI (Network Slice Instance) identification information, and DCN (Dedicated Core Network) identification information, and access network identification information, and may further include other information. Further, when establishing a plurality of PDU sessions, each piece of identification information associated with the PDU session may have the same content or different content. Further, the NSI identification information is information for identifying an NSI and may be an NSI ID or a Slice Instance ID hereinafter.

[0021] Also, as the access network_A and the access network_B, as shown in FIG. 2, any of UTRAN (Universal Terrestrial Radio Access Network)_A20, E-UTRAN (Evolved Universal Terrestrial Radio Access Network)_A80, and NG-RAN (5G-RAN)_A120 may be used. Hereinafter, UTRAN_A20 and / or E-UTRAN_A80 and / or NG-RAN_A120 are referred to as 3GPP access or 3GPP access network, and wireless LAN access network and non-3GPP AN may be referred to as non-3GPP access or non-3GPP access network. Each wireless access network includes a device (e.g., a base station device or an access point) to which UE_A10 is actually connected, etc.

[0022] For example, E-UTRAN_A80 is an access network of LTE and is configured to include one or more eNB_A45. eNB_A45 is a radio base station to which UE_A10 connects via E-UTRA (Evolved Universal Terrestrial Radio Access). Also, when there are a plurality of eNBs in E-UTRAN_A80, each eNB may be connected to each other.

[0023] Also, NG-RAN_A120 is a 5G access network, which may be the (R)AN described in FIG. 4 and is configured to include one or more NR node (New Radio Access Technology node)_A122 and / or ng-eNB. Note that the NR node_A122 is a radio base station to which UE_A10 connects via 5G radio access and is also referred to as gNB. Note that the ng-eNB may be an eNB (E-UTRA) that constitutes a 5G access network and may be connected to the core network_B190 via the NR node_A or directly connected to the core network_B190. Also, when there are a plurality of NR node_A122 and / or ng-eNB in NG-RAN_A120, each NR node_A122 and / or ng-eNB may be connected to each other.

[0024] Note that NG-RAN_A120 may also be an access network configured by E-UTRA and / or 5G Radio Access. In other words, NG-RAN_A120 may include eNB_A45, may include NR node_A122, or may include both. In this case, eNB_A45 and NR node_A122 may be the same device. Therefore, NR node_A122 can be replaced with eNB_A45.

[0025] UTRAN_A20 is an access network of a 3G mobile communication system and is configured to include RNC (Radio Network Controller)_A24 and NB (Node B)_A22. NB_A22 is a radio base station to which UE_A10 connects via UTRA (Universal Terrestrial Radio Access), and UTRA_A20 may be configured to include one or more radio base stations. Also, RNC_A24 is a control unit that connects the core network_A90 and NB_A22, and UTRA_A20 may be configured to include one or more RNCs. Also, RNC_A24 may be connected to one or more NB_A22.

[0026] In the present specification, the fact that UE_A10 is connected to each radio access network means that it is connected to a base station device, an access point, etc. included in each radio access network, and the data, signals, etc. transmitted and received also pass through the base station device or the access point. Note that the control messages transmitted and received between UE_A10 and core network_B190 may be the same control messages regardless of the type of access network. Therefore, the fact that UE_A10 and core network_B190 transmit and receive messages via NR node_A122 may be the same as the fact that UE_A10 and core network_B190 transmit messages via eNB_A45.

[0027] Furthermore, the access network is a radio network connected to UE_A10 and / or the core network. The access network may be a 3GPP access network or a non-3GPP access network. Note that the 3GPP access network may be UTRAN_A20, E-UTRAN_A80, NG-RAN (Radio Access Network)_A120, and the non-3GPP access network may be a wireless LAN access point (WLAN AN). Note that UE_A10 may be connected to the access network or connected to the core network via the access network in order to connect to the core network.

[0028] In addition, DNA5 and PDNA6 are data networks that provide communication services to UE_A10, and may be configured as a packet data service network or may be configured for each service. Furthermore, DNA5 may include connected communication terminals. Therefore, connecting to DNA5 may mean connecting to a communication terminal or server device arranged in DNA5. Furthermore, transmitting and receiving user data with DNA5 may mean transmitting and receiving user data with a communication terminal or server device arranged in DNA5. Also, although DNA5 is outside the core network in FIG. 1, it may be within the core network.

[0029] In addition, core network_A90 and / or core network_B190 may be configured as devices within one or more core networks. Here, the devices within the core network may be devices that execute some or all of the processing or functions of each device included in core network_A90 and / or core network_B190. Note that the devices within the core network may also be referred to as core network devices.

[0030] Furthermore, the core network is an IP mobile communication network operated by a mobile network operator (MNO) connected to the access network and / or the DN. The core network may be a core network for a mobile network operator that operates and manages the mobile communication system 1, or may be a core network for virtual mobile network operators such as MVNO (Mobile Virtual Network Operator) and MVNE (Mobile Virtual Network Enabler), or virtual mobile service providers. Note that the core network_A90 may be the EPC (Evolved Packet Core) that constitutes the EPS (Evolved Packet System), and the core network_B190 may be the 5GC (5G Core Network) that constitutes the 5GS. Furthermore, the core network_B190 may also be the core network of a system that provides 5G communication services. Conversely, the EPC may be the core network_A90, and the 5GC may be the core network_B190. Note that the core network_A90 and / or the core network_B190 are not limited to this, and may also be a network for providing mobile communication services.

[0031] Next, the core network_A90 will be described. The core network_A90 may include at least one of HSS (Home Subscriber Server)_A50, AAA (Authentication Authorization Accounting), PCRF (Policy and Charging Rules Function), PGW_A30, ePDG, SGW_A35, MME (Mobility Management Entity)_A40, SGSN (Serving GPRS Support Node), and SCEF. And these may be configured as NF (Network Function). NF may refer to a processing function configured within the network. Also, the core network_A90 can be connected to a plurality of radio access networks (UTRAN_A20, E-UTRAN_A80).

[0032] For simplicity, FIG. 3 only shows HSS (HSS_A50), PGW (PGW_A30), SGW (SGW_A35), and MME (MME_A40) among these, but it does not mean that no other devices and / or NFs are included. For simplicity, UE_A10 is also referred to as UE, HSS_A50 as HSS, PGW_A30 as PGW, SGW_A35 as SGW, MME_A40 as MME, and DN_A5 and / or PDN_A6 as DN or PDN.

[0033] Hereinafter, a brief description of each device included in the core network_A90 will be given.

[0034] PGW_A30 is a relay device that is connected to the DN, SGW_A35, ePDG, WLAN ANa70, PCRF, and AAA, and transfers user data as a gateway between the DN (DN_A5 and / or PDN_A6) and the core network_A90. Note that PGW_A30 may also be a gateway for IP communication and / or non-IP communication. Furthermore, PGW_A30 may have a function of transferring IP communication, or may have a function of converting non-IP communication and IP communication. Note that multiple such gateways may be arranged in the core network_A90. Furthermore, the multiple gateways arranged may also be gateways that connect the core network_A90 and a single DN.

[0035] Note that the U-Plane (User Plane; UP) may be a communication path for transmitting and receiving user data, and may be composed of multiple bearers. Furthermore, the C-Plane (Control Plane; CP) may be a communication path for transmitting and receiving control messages, and may be composed of multiple bearers.

[0036] Furthermore, PGW_A30 may be connected to the SGW, DN, UPF (User plane function), and / or SMF (Session Management Function), or may be connected to UE_A10 via the U-Plane. Furthermore, PGW_A30 may be configured together with UPF_A235 and / or SMF_A230.

[0037] SGW_A35 is a relay device that is connected to PGW_A30, MME_A40, E-UTRAN_A80, SGSN, and UTRAN_A20, and transfers user data as a gateway between the core network_A90 and the 3GPP access network (UTRAN_A20, GERAN, E-UTRAN_A80).

[0038] MME_A40 is connected to SGW_A35, the access network, HSS_A50, and SCEF, and is a control device that performs location information management including mobility management of UE_A10 via the access network and access control. Further, MME_A40 may include a function as a session management device that manages sessions established by UE_A10. Also, a plurality of such control devices may be arranged in core network_A90. For example, a location management device different from MME_A40 may be configured. A location management device different from MME_A40 may be connected to SGW_A35, the access network, SCEF, and HSS_A50 in the same manner as MME_A40. Further, MME_A40 may be connected to an AMF (Access and Mobility Management Function).

[0039] Also, when a plurality of MMEs are included in core network_A90, the MMEs may be connected to each other. Thereby, the transmission and reception of the context of UE_A10 may be performed between the MMEs. In this way, MME_A40 is a management device that transmits and receives control information related to mobility management and session management with UE_A10. In other words, it may be a control device of the control plane (Control Plane; C-Plane; CP).

[0040] Furthermore, although an example in which MME_A40 is included and configured in core network_A90 has been described, MME_A40 may be a management device configured in one or more core networks or DCNs or NSIs, or a management device connected to one or more core networks or DCNs or NSIs. Here, the plurality of DCNs or NSIs may be operated by a single communication carrier, or may be operated by different communication carriers respectively.

[0041] Also, MME_A40 may be a relay device that transfers user data as a gateway between core network_A90 and the access network. Note that the user data transmitted and received when MME_A40 serves as a gateway may be small data.

[0042] Furthermore, MME_A40 may be an NF responsible for mobility management such as UE_A10, or an NF that manages one or more NSIs. Also, MME_A40 may be an NF that performs these one or more roles. Note that the NF may be a device arranged one or more in core network_A90, may be a CP function (hereinafter also referred to as CPF (Control Plane Function) or Control Plane Network Function) for control information and / or control messages, or may be a shared CP function shared among multiple network slices.

[0043] Here, the NF is a processing function configured in the network. That is, the NF may be a functional device such as MME, SGW, PGW, CPF, AMF, SMF, UPF, etc., or may be function and capability information such as MM (Mobility Management) and SM (Session Management). Also, the NF may be a functional device for realizing a single function, or a functional device for realizing multiple functions. For example, an NF for realizing the MM function and an NF for realizing the SM function may exist separately, or an NF for realizing both the MM function and the SM function may exist.

[0044] HSS_A50 is connected to MME_A40, AAA, and SCEF, and is a management node that manages subscriber information. The subscriber information of HSS_A50 is referred to, for example, during the access control of MME_A40. Furthermore, HSS_A50 may be connected to a location management device different from MME_A40. For example, HSS_A50 may be connected to CPF_A140.

[0045] Furthermore, HSS_A50 and UDM (Unified Data Management)_A245 may be configured as different devices and / or NFs, or may be configured as the same device and / or NF.

[0046] AAA is connected to PGW30, HSS_A50, PCRF, and WLAN ANa70, and performs access control for UE_A10 connected via WLAN ANa70.

[0047] PCRF is connected to PGW_A30, WLAN ANa75, AAA, DN_A5 and / or PDN_A6, and performs QoS management for data delivery. For example, it manages the QoS of the communication path between UE_A10 and DN_A5 and / or PDN_A6. Further, 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.

[0048] Also, PCRF may be a PCF that creates and / or manages policies. More specifically, PCRF may be connected to UPF_A235.

[0049] ePDG is connected to PGW30 and WLAN ANb75, and delivers user data as a gateway between Core Network_A90 and WLAN ANb75.

[0050] SGSN is connected to UTRAN_A20, GERAN, and SGW_A35, and is a control device for location management between 3G / 2G access networks (UTRAN / GERAN) and LTE (4G) access networks (E-UTRAN). Further, SGSN has the selection function of PGW and SGW, the management function of the time zone of UE_A10, and the selection function of MME_A40 at the time of handover to E-UTRAN.

[0051] The SCEF is connected to the DN_A5 and / or PDN_A6, the MME_A40, and the HSS_A50, and is a relay device that transfers user data as a gateway connecting the DN_A5 and / or PDN_A6 and the core network_A90. Note that the SCEF may be a gateway for non-IP communication. Furthermore, the SCEF may have a function of converting non-IP communication and IP communication. Also, a plurality of such gateways may be arranged in the core network_A90. Furthermore, a plurality of gateways connecting the core network_A90 and a single DN_A5 and / or PDN_A6 and / or DN may be arranged. Note that the SCEF may be configured outside or inside the core network.

[0052] Next, the core network_B190 will be described. The core network_B190 may include at least one of an AUSF (Authentication Server Function), an AMF (Access and Mobility Management Function)_A240, a UDSF (Unstructured Data Storage Function), a NEF (Network Exposure Function), an NRF (Network Repository Function), a PCF (Policy Control Function), an SMF (Session Management Function)_A230, a UDM (Unified Data Management), a UPF (User Plane Function)_A235, an AF (Application Function), and an N3IWF (Non-3GPP InterWorking Function). And these may be configured as an NF (Network Function). The NF may refer to a processing function configured in the network.

[0053] For simplicity, FIG. 4 only shows AMF (AMF_A240), SMF (SMF_A230), and UPF (UPF_A235) among these, but it does not mean that other things (devices and / or NFs (Network Functions)) are not included. For simplicity, UE_A10 is also referred to as UE, AMF_A240 as AMF, SMF_A230 as SMF, UPF_A235 as UPF, and DN_A5 as DN.

[0054] Also, FIG. 4 shows N1 interface (hereinafter also referred to as reference point), N2 interface, N3 interface, N4 interface, N6 interface, N9 interface, and N11 interface. Here, the N1 interface is the interface between the UE and the AMF, the N2 interface is the interface between the (R)AN (access network) and the AMF, the N3 interface is the interface between the (R)AN (access network) and the UPF, the N4 interface is the interface between the SMF and the UPF, the N6 interface is the interface between the UPF and the DN, the N9 interface is the interface between the UPF and the UPF, and the N11 interface is the interface between the AMF and the SMF. Using these interfaces, each device can communicate with each other. Here, (R)AN is also referred to as NG RAN hereinafter.

[0055] A brief description of each device included in the core network_B190 is given below.

[0056] First, AMF_A240 is connected to other AMFs, SMF (SMF_A230), access networks (i.e., UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120), UDM, AUSF, and PCF. AMF_A240 may perform functions such as registration management, connection management, reachability management, mobility management of UEs such as UE_A10, transfer of SM (Session Management) messages between the UE and the SMF, access authentication (Access Authentication, Access Authorization), security anchor function (SEA), security context management (SCM), support for the N2 interface to N3IWF, support for sending and receiving NAS signals to / from the UE via N3IWF, authentication of the UE connected via N3IWF, management of RM states (Registration Management states), management of CM states (Connection Management states), etc. Also, one or more AMF_A240s may be deployed within the core network_B190. Further, AMF_A240 may be an NF that manages one or more NSIs (Network Slice Instances). Additionally, AMF_A240 may be a common CP function (CCNF; Common CPNF (Control Plane Network Function)) shared among multiple NSIs.

[0057] Also, the RM state includes an unregistered state (RM-DEREGISTERED state) and a 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.

[0058] Also, the CM state includes an idle state (CM-IDLE state) and a connected state (CM-CONNECTED state). In the CM-IDLE state, the UE is in the RM-REGISTERED state but does not have a NAS signaling connection established with the AMF via the N1 interface. Also, in the CM-IDLE state, the UE does not have an N2 connection and an N3 connection. On the other hand, in the CM-CONNECTED state, the UE has a NAS signaling connection established with the AMF via the N1 interface. Also, in the CM-CONNECTED state, the UE may have an N2 connection and / or an N3 connection.

[0059] In addition, the SMF_A230 may have functions such as session management (SM) for PDU sessions and the like, IP address allocation to the UE and its management function, UPF selection and control function, UPF setting function for routing traffic to an appropriate destination, downlink data notification function, function of providing AN-specific SM information transmitted via the N2 interface to the AN via the AMF, function of determining the SSC mode (Session and Service Continuity mode) for the session, roaming function, and the like. Further, the SMF_A230 may be connected to the AMF_A240, UPF_A235, UDM, and PCF.

[0060] In addition, UPF_A235 is connected to DN_A5, SMF_A230, other UPFs, and the access network (i.e., UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120). UPF_A235 serves as an anchor for intra-RAT mobility or inter-RAT mobility, packet routing & forwarding, supports the UL CL (Uplink Classifier) function for routing multiple traffic flows for one DN, the Branching point function for supporting multi-homed PDU sessions, QoS processing for the user plane, verification of uplink traffic, buffering of downlink packets, the trigger function for Downlink Data Notification, etc. Also, UPF_A235 may be a relay device for transferring user data as a gateway between DN_A5 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 to 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.

[0061] Note that between UPF_A235 and the access network, UPF_C239, which is a UPF different from UPF_A235 (also referred to as a branching point or uplink classifier), may exist as a device or NF. When UPF_C239 exists, the PDU session between UE_A10 and DN_A5 will be established via the access network, UPF_C239, and UPF_A235.

[0062] In addition, the AUSF is connected to the UDM and the AMF_A240. The AUSF functions as an authentication server.

[0063] The UDSF provides a function for all NFs to store and retrieve information as unstructured data.

[0064] The NEF provides a means to securely provide service capabilities offered by the 3GPP network. It stores information received from other NFs as structured data.

[0065] When the NRF receives an NF Discovery Request from an NF instance, it provides information about the discovered NF instance to that NF, or holds information about available NF instances and the services supported by those instances.

[0066] The PCF is connected to the SMF (SMF_A230), AF, and AMF_A240. It provides policy rules and the like.

[0067] The UDM is connected to the AMF_A240, SMF (SMF_A230), AUSF, and PCF. The UDM includes a UDM FE (application front end) and a UDR (User Data Repository). The UDM FE performs processes such as authentication information, location management, and subscription management. The UDR stores the data required by the UDM FE and the policy profiles required by the PCF.

[0068] The AF is connected to the PCF. The AF affects traffic routing and participates in policy control.

[0069] The N3IWF provides functions such as establishment of an IPsec tunnel with the UE, relaying of NAS (N1) signaling between the UE and the AMF, processing of N2 signaling sent from the SMF and relayed by the AMF, establishment of an IPsec Security Association (IPsec SA), relaying of user plane packets between the UE and the UPF, and AMF selection.

[0070] Also, the S1 mode is a UE mode in which messages can be transmitted and received using the S1 interface. Note that the S1 interface may be composed of the S1-MME interface, the S1-U interface, and the X2 interface connecting radio base stations.

[0071] A UE in the S1 mode can access the EPC via an eNB providing E-UTRA functions or access the EPC via an en-gNB providing NR functions, for example.

[0072] Note that although access to the EPC via an eNB providing E-UTRA functions and access to the EPC via an en-gNB providing NR functions are regarded as the S1 mode, they may be configured as separate and different modes.

[0073] Also, the N1 mode is a UE mode in which the UE can access the 5GC via a 5G access network. Also, the N1 mode may be a UE mode in which messages can be transmitted and received using the N1 interface. Note that the N1 interface may be composed of the N1 interface and the Xn interface connecting radio base stations.

[0074] A UE in the N1 mode can access the 5GC via an ng-eNB providing E-UTRA functions or access the 5GC via a gNB providing NR functions, for example.

[0075] Currently, the access to the 5GC via the ng-eNB that provides E-UTRA functions and the access to the 5GC via the gNB that provides NR functions are in N1 mode, but they may be configured as individual different modes.

[0076] [1.2. Configuration of Each Device] The configuration of each device will be described below. Note that part or all of the functions of each of the following devices and each part of the devices may operate on physical hardware, or may operate on logical hardware virtually configured on general-purpose hardware.

[0077] [1.2.1. Configuration of UE] First, an example of the device configuration of UE_A10 is shown in FIG. 5. As shown in FIG. 5, UE_A10 is composed of a control unit _A500, a transceiver unit _A520, and a storage unit _A540. The transceiver unit _A520 and the storage unit _A540 are connected to the control unit _A500 via a bus. Also, an external antenna 410 is connected to the transceiver unit _A520.

[0078] The control unit _A500 is a functional unit for controlling the entire UE_A10. By reading and executing various information and programs stored in the storage unit _A540, it realizes various processes of the entire UE_A10.

[0079] The transceiver unit _A520 is a functional unit for the UE_A10 to connect to base stations (UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120) and / or a wireless LAN access point (WLAN AN) in the access network and to connect to the access network. In other words, the UE_A10 can connect to base stations and / or access points in the access network via the external antenna 410 connected to the transceiver unit _A520. Specifically, the UE_A10 can transmit and receive user data and / or control information to and from base stations and / or access points in the access network via the external antenna 410 connected to the transceiver unit _A520.

[0080] The memory unit _A540 is a functional unit that stores programs, data, etc. necessary for each operation of the UE_A10, and is composed of, for example, a semiconductor memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), etc. The memory unit _A540 stores identification information, control information, flags, parameters, rules, policies, etc. included in control messages transmitted and received within the communication procedure described later.

[0081] [1.2.2. eNB / NR node] Next, an example of the device configuration of the eNB_A45 and the NR node_A122 is shown in FIG. 6. As shown in FIG. 6, the eNB_A45 and the NR node_A122 are composed of a control unit _B600, a network connection unit _B620, a transmission / reception unit _B630, and a memory unit _B640. The network connection unit _B620, the transmission / reception unit _B630, and the memory unit _B640 are connected to the control unit _B600 via a bus. Also, an external antenna 510 is connected to the transmission / reception unit _B630.

[0082] The control unit _B600 is a functional unit for controlling the entire eNB_A45 and NR node_A122. By reading and executing various types of information and programs stored in the memory unit _B640, it realizes various processes of the entire eNB_A45 and NR node_A122.

[0083] The network connection unit _B620 is a functional unit for the eNB_A45 and the NR node_A122 to connect to the AMF_A240 and the UPF_A235 in the core network. In other words, the eNB_A45 and the NR node_A122 can be connected to the AMF_A240 and the UPF_A235 in the core network via the network connection unit _B620. Specifically, the eNB_A45 and the NR node_A122 can transmit and receive user data and / or control information to and from the AMF_A240 and / or the UPF_A235 via the network connection unit _B620.

[0084] The transmission / reception unit _B630 is a functional unit for eNB_A45 and NR node_A122 to connect to UE_A10. In other words, eNB_A45 and NR node_A122 can transmit and receive user data and / or control information to and from UE_A10 via the transmission / reception unit _B630.

[0085] The storage unit _B640 is a functional unit that stores programs, data, etc. necessary for the operations of eNB_A45 and NR node_A122. The storage unit _B640 is composed of, for example, a semiconductor memory, an HDD, an SSD, etc. The storage unit _B640 stores identification information, control information, flags, parameters, etc. included in the control messages transmitted and received in the communication procedure described later. The storage unit _B640 may store these information as context for each UE_A10.

[0086] [1.2.3. Configuration of MME / AMF] Next, an example of the device configuration of MME_A40 or AMF_A240 is shown in FIG. 7. As shown in FIG. 7, MME_A40 or AMF_A240 is composed of a control unit _C700, a network connection unit _C720, and a storage unit _C740. The network connection unit _C720 and the storage unit _C740 are connected to the control unit _C700 via a bus. Also, the storage unit _C740 stores a context 642.

[0087] The control unit _C700 is a functional unit for controlling the entire MME_A40 or AMF_A240. By reading and executing various information and programs stored in the storage unit _C740, various processes of the entire AMF_A240 are realized.

[0088] The network connection unit _C720 is a functional unit for the MME _A40 or the AMF _A240 to connect to other MMEs _A40, AMFs _240, SMFs _A230, base stations (UTRAN _A20, E-UTRAN _A80, and NG-RAN _A120) in the access network and / or wireless LAN access points (WLAN ANs), UDMs, AUSFs, and PCFs. In other words, the MME _A40 or the AMF _A240 can transmit and receive user data and / or control information to and from base stations and / or access points, UDMs, AUSFs, and PCFs in the access network via the network connection unit _C720.

[0089] The storage unit _C740 is a functional unit that stores programs, data, etc. required for the operations of each of the MME _A40 or the AMF _A240. The storage unit _C740 is composed of, for example, a semiconductor memory, an HDD, an SSD, etc. The storage unit _C740 stores identification information, control information, flags, parameters, etc. included in control messages transmitted and received within the communication procedure described later. As the context 642 stored in the storage unit _C740, there may be a context stored for each UE, a context stored for each PDU session, or a context stored for each bearer. The context stored for each UE may include IMSI, MSISDN, MM State, GUTI, ME Identity, UE Radio Access Capability, UE Network Capability, MS Network Capability, Access Restriction, MME F-TEID, SGW F-TEID, eNB Address, MME UE S1AP ID, eNB UE S1AP ID, NR node Address, NR node ID, WAG Address, WAG ID. Further, the context stored for each PDU session may include APN in Use, Assigned Session Type, IP Address(es), PGW F-TEID, SCEF ID, Default bearer. Further, the context stored for each bearer may include EPS Bearer ID, TI, TFT, SGW F-TEID, PGW F-TEID, MME F-TEID, eNB Address, NR node Address, WAG Address, eNB ID, NR node ID, WAG ID.

[0090] [1.2.4. Configuration of SMF] Next, an example of the device configuration of SMF_A230 is shown in FIG. 8. As shown in FIG. 8, SMF_A230 is composed of a control unit _D800, a network connection unit _D820, and a storage unit _D840, respectively. The network connection unit _D820 and the storage unit _D840 are connected to the control unit _D800 via a bus. Further, the storage unit _D840 stores the context 742.

[0091] The control unit _D800 of SMF_A230 is a functional unit for controlling the entire SMF_A230. By reading and executing various information and programs stored in the storage unit _D840, various processes of the entire SMF_A230 are realized.

[0092] Also, the network connection unit _D820 of SMF_A230 is a functional unit for SMF_A230 to connect to AMF_A240, UPF_A235, UDM, and PCF. In other words, SMF_A230 can transmit and receive user data and / or control information to and from AMF_A240, UPF_A235, UDM, and PCF via the network connection unit _D820.

[0093] In addition, the storage unit _D840 of SMF_A230 is a functional unit that stores programs, data, etc. required for each operation of SMF_A230. The storage unit _D840 of SMF_A230 is composed of, for example, a semiconductor memory, an HDD, an SSD, etc. The storage unit _D840 of SMF_A230 stores identification information, control information, flags, parameters, etc. included in control messages transmitted and received within the communication procedure described later. Also, as the context 742 stored in the storage unit _D840 of SMF_A230, there may be a context stored for each UE, a context stored for each APN, a context stored for each PDU session, and a context stored for each bearer. The context stored for each UE may include IMSI, ME Identity, MSISDN, RAT type. The context stored for each APN may include APN in use. Note that the context stored for each APN may be stored for each Data Network Identifier. The context stored for each PDU session may include Assigned Session Type, IP Address(es), SGW F-TEID, PGW F-TEID, Default Bearer. The context stored for each bearer may include EPS Bearer ID, TFT, SGW F-TEID, PGW F-TEID.

[0094] [1.2.5.Configuration of PGW / UPF] Next, an example of the device configuration of PGW_A30 or UPF_A235 is shown in FIG. 8. As shown in FIG. 8, PGW_A30 or UPF_A235 is each composed of a control unit _D800, a network connection unit _D820, and a storage unit _D840. The network connection unit _D820 and the storage unit _D840 are connected to the control unit _D800 via a bus. Also, the storage unit _D840 stores the context 742.

[0095] The control unit _D800 of PGW_A30 or UPF_A235 is a functional unit for controlling the entire PGW_A30 or UPF_A235. By reading and executing various information and programs stored in the storage unit _D840, it realizes various processes of the entire PGW_A30 or UPF_A235.

[0096] Also, the network connection unit _D820 of PGW_A30 or UPF_A235 is a functional unit for PGW_A30 or UPF_A235 to connect to the DN (that is, DN_A5), SMF_A230, other UPF_A235, and the access network (that is, UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120). In other words, UPF_A235 can send and receive user data and / or control information to and from the DN (that is, DN_A5), SMF_A230, other UPF_A235, and the access network (that is, UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120) via the network connection unit _D820.

[0097] Also, the storage unit _D840 of UPF_A235 is a functional unit that stores programs, data, etc. necessary for each operation of UPF_A235. The storage unit _D840 of UPF_A235 is composed of, for example, a semiconductor memory, an HDD, an SSD, etc. The storage unit _D840 of UPF_A235 stores identification information, control information, flags, parameters, etc. included in the control messages transmitted and received within the communication procedure described later. Further, as the context 742 stored in the storage unit _D840 of UPF_A235, there may be a context stored for each UE, a context stored for each APN, a context stored for each PDU session, and a context stored for each bearer. The context stored for each UE may include IMSI, ME Identity, MSISDN, and RAT type. The context stored for each APN may include APN in use. Note that the context stored for each APN may be stored for each Data Network Identifier. The context stored for each PDU session may include Assigned Session Type, IP Address(es), SGW F-TEID, PGW F-TEID, and Default Bearer. The context stored for each bearer may include EPS Bearer ID, TFT, SGW F-TEID, and PGW F-TEID.

[0098] [1.2.6. Information Stored in the Storage Unit of Each of the Above Devices] Next, each piece of information stored in the storage unit of each of the above devices will be described.

[0099] IMSI (International Mobile Subscriber Identity) is the permanent identification information of a subscriber (user) and is the identification information assigned to the user who uses the UE. The IMSI stored in UE_A10, MME_A40 / CPF_A140 / AMF_A2400, and SGW_A35 may be equal to the IMSI stored in HSS_A50.

[0100] The EMM State / MM State indicates the mobility management state of UE_A10 or MME_A40 / CPF_A140 / AMF_A240. For example, the EMM State / MM State may be the EMM-REGISTERED state (registered state) in which UE_A10 is registered with the network and / or the EMM-DEREGISTERED state (deregistered state) in which UE_A10 is not registered with the network. Also, the EMM State / MM State may be the ECM-CONNECTED state in which the connection between UE_A10 and the core network is maintained and / or the ECM-IDLE state in which the connection is released. Note that the EMM State / MM State may be information that can distinguish between the state in which UE_A10 is registered with the EPC and the state in which it is registered with the NGC or 5GC.

[0101] The GUTI (Globally Unique Temporary Identity) is temporary identification information of UE_A10. The GUTI is composed of the identification information of MME_A40 / CPF_A140 / AMF_A240 (GUMMEI (Globally Unique MME Identifier)) and the identification information of UE_A10 within a specific MME_A40 / CPF_A140 / AMF_A240 (M-TMSI (M-Temporary Mobile Subscriber Identity)). The ME Identity is the ID of UE_A10 or the ME and may be, for example, IMEI (International Mobile Equipment Identity) or IMEISV (IMEI Software Version). The MSISDN represents the basic telephone number of UE_A10. The MSISDN stored in MME_A40 / CPF_A140 / AMF_A240 may be the information indicated by the storage unit of HSS_A50. Note that the GUTI may include information for identifying CPF_140.

[0102] The MME F-TEID is information for identifying MME_A40 / CPF_A140 / AMF_A240. The MME F-TEID may include the IP address of MME_A40 / CPF_A140 / AMF_A240, or may include the TEID (Tunnel Endpoint Identifier) of MME_A40 / CPF_A140 / AMF_A240, or may include both of them. Also, the IP address of MME_A40 / CPF_A140 / AMF_A240 and the TEID of MME_A40 / CPF_A140 / AMF_A240 may be stored independently. Further, the MME F-TEID may be identification information for user data or identification information for control information.

[0103] The SGW F-TEID is information for identifying SGW_A35. The SGW F-TEID may include the IP address of SGW_A35, or may include the TEID of SGW_A35, or may include both of them. Also, the IP address of SGW_A35 and the TEID of SGW_A35 may be stored independently. Further, the SGW F-TEID may be identification information for user data or identification information for control information.

[0104] The PGW F-TEID is information for identifying PGW_A30 / UPGW_A130 / SMF_A230 / UPF_A235. The PGW F-TEID may include the IP address of PGW_A30 / UPGW_A130 / SMF_A230 / UPF_A235, or may include the TEID of PGW_A30 / UPGW_A130 / SMF_A230 / UPF_A235, or may include both of them. Also, the IP address of PGW_A30 / UPGW_A130 / SMF_A230 / UPF_A235 and the TEID of PGW_A30 / UPGW_A130 / SMF_A230 / UPF_A235 may be stored independently. Further, the PGW F-TEID may be identification information for user data or identification information for control information.

[0105] The eNB F-TEID is information that identifies eNB_A45. The eNB F-TEID may include the IP address of eNB_A45, the TEID of eNB_A45, or both. Also, the IP address of eNB_A45 and the TEID of SGW_A35 may be stored independently. Further, the eNB F-TEID may be identification information for user data or control information.

[0106] Also, the APN may be identification information that differentiates the core network from an external network such as a DN. Furthermore, the APN can also be used as information for selecting gateways such as PGW_A30 / UPGW_A130 / UPF_A235 that connect to the core network A_90. Note that the APN may be a DNN (Data Network Name). Therefore, the APN may be referred to as the DNN, or the DNN may be referred to as the APN.

[0107] Note that the APN may be identification information that identifies such gateways or identification information that identifies an external network such as a DN. When multiple gateways are arranged to connect the core network and the DN, there may be multiple gateways selectable by the APN. Furthermore, one of such multiple gateways may be selected by another method using identification information other than the APN.

[0108] UE Radio Access Capability is identification information indicating the radio access capability of UE_A10. UE Network Capability includes security algorithms and key derivation functions supported by UE_A10. MS Network Capability is information including one or more pieces of information required for SGSN_A42 for UE_A10 having GERAN_A25 and / or UTRAN_A20 functions. Access Restriction is registration information for access restriction. eNB Address is the IP address of eNB_A45. MME UE S1AP ID is information for identifying UE_A10 within MME_A40 / CPF_A140 / AMF_A240. eNB UE S1AP ID is information for identifying UE_A10 within eNB_A45.

[0109] APN in Use is the most recently used APN. APN in Use may also be a Data Network Identifier. This APN may be composed of network identification information and default operator identification information. Furthermore, APN in Use may also be information for identifying the DN to which the PDU session is to be established.

[0110] Assigned Session Type is information indicating the type of the PDU session. Assigned Session Type may also be Assigned PDN Type. The type of the PDU session may be IP or non-IP. Furthermore, when the type of the PDU session is IP, it may further include information indicating the type of the PDN assigned from the network. Note that Assigned Session Type may be IPv4, IPv6, or IPv4v6.

[0111] Also, unless otherwise specified, the IP Address is the IP address assigned to the UE. The IP address may be an IPv4 address, an IPv6 address, an IPv6 prefix, or an interface ID. Note that when the Assigned Session Type indicates non-IP, it may not include the element of IP Address.

[0112] The DN ID is identification information for distinguishing between the core network_B190 and an external network such as the DN. Furthermore, the DN ID can also be used as information for selecting a gateway such as the UPGW_A130 or PF_A235 that connects to the core network_B190.

[0113] Note that the DN ID may be identification information for identifying such gateways or identification information for identifying an external network such as the DN. When multiple gateways are arranged to connect the core network_B190 and the DN, there may be multiple gateways selectable by the DN ID. Furthermore, one gateway may be selected from among such multiple gateways by another method using identification information other than the DN ID.

[0114] Furthermore, the DN ID may be information equal to the APN or information different from the APN. Note that when the DN ID and the APN are different information, each device may manage information indicating the correspondence between the DN ID and the APN, may perform a procedure for querying the APN using the DN ID, or may perform a procedure for querying the DN ID using the APN.

[0115] The SCEF ID is the IP address of the SCEF_A46 used in the PDU session. The Default Bearer is information obtained and / or generated at the time of PDU session establishment, and is EPS bearer identification information for identifying the default bearer associated with the PDU session.

[0116] The EPS Bearer ID is the identification information of the EPS bearer. Also, the EPS Bearer ID may be the identification information that identifies the SRB (Signalling Radio Bearer) and / or the CRB (Control-plane Radio bearer), or may be the identification information that identifies the DRB (Data Radio Bearer). The TI (Transaction Identifier) is the identification information that identifies the two-way message flow (Transaction). Note that the EPS Bearer ID may be the EPS bearer identification information that identifies the dedicated bearer. Therefore, it may be the identification information that identifies an EPS bearer different from the default bearer. The TFT indicates all the packet filters associated with the EPS bearer. The TFT is the information that identifies a part of the user data to be transmitted and received, and the UE_A10 transmits and receives the user data identified by the TFT using the EPS bearer associated with the TFT. In other words, the UE_A10 transmits and receives the user data identified by the TFT using the RB (Radio Bearer) associated with the TFT. Also, the TFT may associate the user data such as the application data to be transmitted and received with an appropriate transfer path, or may be the identification information that identifies the application data. Also, the UE_A10 may transmit and receive the user data that cannot be identified by the TFT using the default bearer. Also, the UE_A10 may store in advance the TFT associated with the default bearer.

[0117] The Default Bearer is EPS bearer identification information that identifies the default bearer associated with a PDU session. Note that an EPS bearer may be a logical communication path established between UE_A10 and PGW_A30 / UPGW_A130 / UPF_A235, or a communication path that constitutes a PDN connection / PDU session. Furthermore, an EPS bearer may be a default bearer or a dedicated bearer. Additionally, an EPS bearer may be configured to include an RB established between UE_A10 and a base station and / or access point within the access network. Moreover, the RB and the EPS bearer may be associated on a one-to-one basis. Therefore, the identification information of the RB may be associated with the identification information of the EPS bearer on a one-to-one basis or may be the same identification information. Note that the RB may be an SRB and / or CRB or a DRB. Also, the Default Bearer may be information obtained by UE_A10 and / or SGW_A35 and / or PGW_A30 / UPGW_A130 / SMF_A230 / UPF_A235 from the core network at the time of PDU session establishment. Note that the default bearer is the first EPS bearer established during a PDN connection / PDU session and is an EPS bearer that can be established only once within one PDN connection / PDU session. The default bearer may be an EPS bearer that can be used for the communication of user data not associated with a TFT. Also, the dedicated bearer is an EPS bearer established after the default bearer is established during a PDN connection / PDU session and is an EPS bearer that can be established multiple times within one PDN connection / PDU session. The dedicated bearer may be an EPS bearer that can be used for the communication of user data associated with a TFT.

[0118] User Identity is information that identifies a subscriber. User Identity may be an IMSI or an MSISDN. Furthermore, User Identity may be identification information other than IMSI and MSISDN. Serving Node Information is information that identifies the MME_A40 / CPF_A140 / AMF_A240 used in a PDU session, and may be the IP address of the MME_A40 / CPF_A140 / AMF_A240.

[0119] The eNB Address is the IP address of eNB_A45. The eNB ID is information that identifies a UE within eNB_A45. The MME Address is the IP address of the MME_A40 / CPF_A140 / AMF_A240. The MME ID is information that identifies the MME_A40 / CPF_A140 / AMF_A240. The NR node Address is the IP address of NR node_A122. The NR node ID is information that identifies NR node_A122. The WAG Address is the IP address of the WAG. The WAG ID is information that identifies the WAG.

[0120] An anchor, or anchor point, is a UFP with a gateway function for the DN and PDU session. The UPF serving as the anchor point may be a PDU session anchor or an anchor.

[0121] The SSC mode indicates the mode of Session and Service Continuity that the system and / or each device supports in 5GC. More specifically, it may be a mode indicating the type of service session continuity supported by the PDU session established between UE_A10 and the anchor point. Here, the anchor point may be UPGW or UPF_A235. Note that the SSC mode may also be a mode indicating the type of service session continuity set for each PDU session. Furthermore, the SSC mode may be composed of three modes: SSC mode 1, SSC mode 2, and SSC mode 3. The SSC mode is associated with the anchor point and cannot be changed while the PDU session is established.

[0122] Furthermore, SSC mode 1 is a mode of service session continuity in which the same UPF continues to be maintained as the anchor point regardless of the radio access technology (RAT), such as the cell used when UE_A10 connects to the network. More specifically, SSC mode 1 may be a mode that realizes service session continuity without changing the anchor point used by the established PDU session even when mobility of UE_A10 occurs.

[0123] Furthermore, SSC mode 2 is a mode of service session continuity in which, when a PDU session contains one anchor point associated with SSC mode 2, the PDU session is first released and then a new PDU session is established continuously. More specifically, SSC mode 2 is a mode in which, when relocation of the anchor point occurs, the PDU session is deleted once and then a new PDU session is established.

[0124] Furthermore, SSC mode 2 is a mode of service session continuity that continues to maintain the same UPF as the anchor point only within the serving area of the UPF. More specifically, SSC mode 2 may be a mode that realizes service session continuity without changing the UPF used by the established PDU session as long as UE_A10 is within the serving area of the UPF. Furthermore, SSC mode 2 may be a mode that realizes service session continuity by changing the UPF used by the established PDU session when mobility of UE_A10 occurs such that it exits the serving area of the UPF.

[0125] Here, the serving area of the TUPF may be an area where one UPF can provide a service session continuity function, or may be a subset of the access network such as the RAT or cell used when UE_A10 connects to the network. Furthermore, the subset of the access network may be a network composed of one or more RATs and / or cells, or may be a TA.

[0126] Furthermore, SSC mode 3 is a mode of service session continuity that can establish a PDU session between a new anchor point and the UE for the same DN without releasing the PDU session between the UE and the anchor point.

[0127] Furthermore, SSC mode 3 is a mode of service session continuity that permits the establishment of a new PDU session and / or communication path via a new UPF for the same DN before disconnecting the PDU session and / or communication path established between UE_A10 and the UPF. Furthermore, SSC mode 3 may be a mode of service session continuity that permits UE_A10 to be multi-homed.

[0128] And / or, SSC mode 3 may be a mode in which service session continuity using a plurality of PDU sessions and / or UPFs associated with the PDU sessions is permitted. In other words, in the case of SSC mode 3, each device may achieve service session continuity using a plurality of PDU sessions, or may achieve service session continuity using a plurality of TUPFs.

[0129] Here, when each device establishes a new PDU session and / or communication path, the selection of the new UPF may be performed by the network, or the new UPF may be the UPF that is optimal for the location where UE_A10 is connected to the network. Further, when a plurality of PDU sessions and / or the UPFs used by the PDU sessions are valid, UE_A10 may immediately associate the application and / or flow communication with the newly established PDU session, or may perform the association based on the completion of the communication.

[0130] [1.3. Explanation of Initial Procedures] Next, before explaining the detailed procedures of the initial procedures, in order to avoid duplicate explanations, specific terms and the main identification information used in each procedure will be explained in advance.

[0131] The network refers to at least a part of access network_A20 / 80, access network_B80 / 120, core network_A90, core network_B190, DN_A5, and PDN_A6. Also, one or more devices included in at least a part of access network_A20 / 80, access network_B80 / 120, core network_A90, core network_B190, DN_A5, and PDN_A6 may be referred to as a network or a network device. That is, when the network transmits and / or receives a message and / or executes a procedure, it means that a device (network device) in the network transmits and / or receives a message and / or executes a procedure.

[0132] Session Management (SM) messages (also referred to as NAS (Non-Access-Stratum) SM messages or simply SM messages) are NAS messages used in procedures for SM (also referred to as session management procedures or SM procedures), and may be control messages transmitted and received between UE_A10 and SMF_A230 via AMF_A240. Furthermore, SM messages may include PDU session establishment request messages, PDU session establishment acceptance messages, PDU session completion messages, PDU session establishment rejection messages, PDU session modification request messages, PDU session modification acceptance messages, PDU session modification rejection messages, and the like. Also, procedures for SM may include PDU session establishment procedures, PDU session modification procedures, and the like.

[0133] Among SM messages, the messages transmitted by UE_A10 are referred to as SM request messages. Specifically, the PDU session establishment request message and the PDU session modification request message are SM request messages.

[0134] A tracking area (TA, also referred to as a Tracking Area) is a range that can be represented by the location information of UE_A10 and is managed by the core network, and may be composed of, for example, one or more cells. Also, the TA may be a range in which control messages such as paging messages are broadcast, or a range in which UE_A10 can move without performing a handover procedure.

[0135] A TA list is a list that contains one or more TAs assigned by the network to UE_A10. Note that UE_A10 may be able to move without performing a registration procedure while moving within one or more TAs included in the TA list. In other words, the TA list may be a group of information indicating an area where UE_A10 can move without performing a registration procedure.

[0136] A network slice is a logical network that provides specific network capabilities and network characteristics. Hereinafter, a network slice is also referred to as an NW slice.

[0137] An NSI (Network Slice Instance) is an entity of a network slice that is configured with one or more in the core network_B190. Also, the NSI may be composed of virtual NFs (Network Functions) generated using an NST (Network Slice Template). Here, the NST is associated with resource requirements for providing required communication services and capabilities, and is a logical representation of one or more NFs (Network Functions). That is, the NSI may be an aggregate within the core network_B190 composed of a plurality of NFs. Also, the NSI may be a logical network configured to separate user data delivered by services and the like. At least one or more NFs may be configured in a network slice. The NFs configured in a network slice may or may not be devices shared with other network slices. The UE_A10 and / or devices in the network can be assigned to one or more network slices based on registration information such as NSSAI and / or S-NSSAI and / or UE usage type and / or one or more network slice type IDs and / or one or more NS IDs, etc. and / or APN.

[0138] S-NSSAI is the abbreviation of Single Network Slice Selection Assistance information and is information for identifying a network slice. S-NSSAI may be composed of SST (Slice / Service type) and SD (Slice Differentiator). S-NSSAI may be composed of only SST or may be composed of both SST and SD. Here, SST is information indicating the operation of a network slice expected in terms of functions and services. Also, SD may be information that complements SST when selecting one NSI from a plurality of NSIs indicated by SST. S-NSSAI may be information unique to each PLMN (Public Land Mobile Network), may be standard information shared among PLMNs, or may be information unique to different communication carriers for each PLMN.

[0139] More specifically, SST and / or SD may be standard information (Standard Value) shared among PLMNs or may be information unique to different communication carriers for each PLMN (Non Standard Value). Also, the network may store one or more S-NSSAIs in the registration information of UE_A10 as the default S-NSSAI.

[0140] NSSAI (Single Network Slice Selection Assistance information) is a collection of S-NSSAIs. Each S-NSSAI included in NSSAI is information that assists an access network or a core network in selecting an NSI. UE_A10 may store the NSSAI permitted by the network for each PLMN. Also, NSSAI may be information used to select AMF_A240.

[0141] The Operator A network is a network operated by Network Operator A (Operator A). Here, for example, Operator A may deploy a common NW slice with Operator B described below.

[0142] The Operator B network is a network operated by Network Operator B (Operator B). Here, for example, Operator B may deploy a common NW slice with Operator A.

[0143] The first NW slice is the NW slice to which the established PDU session belongs when the UE connects to a specific DN. For example, the first NW slice may be an NW slice managed within the Operator A network, or may be an NW slice commonly managed within the Operator B network.

[0144] The second NW slice is the NW slice to which another PDU session that can connect to the DN to which the PDU session belonging to the first NW slice is connected as the destination belongs. Note that the first NW slice and the second NW slice may be operated by the same operator or may be operated by different operators.

[0145] An equivalent PLMN is a PLMN that is treated as the same PLMN as any PLMN in the network.

[0146] The DCN (Dedicated Core Network) is a core network dedicated to a specific subscriber type, which is composed of one or more within the core network_A90. Specifically, for example, a DCN for a UE registered as a user of the M2M (Machine to Machine) communication function may be configured within the core network_A90. In addition, a default DCN for a UE without an appropriate DCN may be configured within the core network_A90. Furthermore, at least one or more MME_40 or SGSN_A42 may be arranged in the DCN, and furthermore, at least one or more SGW_A35 or PGW_A30 or PCRF_A60 may be arranged. Note that the DCN may be identified by a DCN ID, and furthermore, the UE may be assigned to one DCN based on information such as the UE usage type and / or DCN ID.

[0147] The first timer is a timer that manages the start of procedures for session management such as PDU session establishment procedures and / or the transmission of SM (Session Management) messages such as PDU session establishment request messages, and may be information indicating the value of a backoff timer for managing the behavior of session management. Hereinafter, the first timer and / or the backoff timer may be referred to as a timer. While the first timer is running, the start of procedures for session management and / or the transmission and reception of SM messages of each device may be prohibited. Note that the first timer may be set in association with at least one of the congestion management unit applied by the NW and / or the congestion management unit identified by the UE. For example, it may be set in at least one unit of the APN / DNN unit, and / or the identification information unit indicating one or more NW slices, and / or the rejection reason value unit in the session management procedure, and / or the session unit in which rejection is indicated in the session management procedure, and / or the PTI unit of the session management procedure.

[0148] Furthermore, the SM message may be an NAS message used in procedures for session management, and may be a control message transmitted and received between the UE_A10 and the SMF_A230 via the AMF_A240. Further, the SM message may include a PDU session establishment request message, a PDU session establishment acceptance message, a PDU session completion message, a PDU session establishment rejection message, a PDU session modification request message, a PDU session modification acceptance message, a PDU session modification rejection message, and the like. Further, procedures for session management may include a PDU session establishment procedure, a PDU session modification procedure, and the like. Also, in these procedures, a backoff timer value may be included for each message received by the UE_A10. The UE may set the backoff timer received from the NW as the first timer, or may set the timer value in another way, or may set a random value. Also, when the backoff timer received from the NW is composed of a plurality of timers, the UE may manage a plurality of "first timers" corresponding to the plurality of backoff timers, or based on the policy held by the UE, select one timer value from the plurality of backoff timer values received from the NW, set it in the first timer, and manage it. For example, when receiving two backoff timer values, the UE may set the backoff timer values received from the NW in "first timer #1" and "first timer #2" respectively, and manage them. Also, based on the policy held by the UE, one value may be selected from the plurality of backoff timer values received from the NW, set in the first timer, and managed.

[0149] When the UE_A10 receives a plurality of backoff timer values from the NW, it may manage a plurality of "first timers" corresponding to the plurality of backoff timers. Here, in order to distinguish the plurality of "first timers" received by the UE_A10, hereinafter, it may be described as, for example, "first timer #1" or "first timer #2". The plurality of backoff timers may be acquired in one session management procedure, or may be acquired in different session management procedures.

[0150] Here, the first timer is set for a plurality of related NW slices based on the information for identifying one NW slice as described above, and may be a back-off timer for suppressing reconnection, or a back-off timer set in units of a combination of an APN / DNN and one NW slice for preventing reconnection. However, it is not limited thereto, and it may also be a back-off timer set in units of a combination of a plurality of related NW slices based on the information for identifying an APN / DNN and one NW slice for suppressing reconnection.

[0151] The re-attempt information included in the eleventh identification information is information for the network (NW) to instruct UE_A10 whether to allow reconnection for a rejected PDU session establishment request (S1100) using the same DNN information and / or S-NSSAI information.

[0152] At this time, in the PDU session establishment request (1100), when the UE executes a PDU session establishment request (S1100) that does not include a DNN, not including the DNN is referred to as the same information. Also, in the PDU session establishment request (1100), when the UE executes a PDU session establishment request (S1100) that does not include an S-NSSAI, not including the S-NSSAI is referred to as the same information.

[0153] In addition, the re-attempt information may be set in units of UTRAN access and / or E-UTRAN access and / or NR access and / or slice information and / or equivalent PLMN and / or S1 mode and / or NW mode.

[0154] Furthermore, the re-attempt information specified in an access unit (UTRAN access, E-UTRAN access, NR access) may be information indicating reconnection using the same information to the network on the premise of access change. The re-attempt information specified in a slice unit may be information where slice information different from the rejected slice is specified, and reconnection using the specified slice information may be permitted.

[0155] Furthermore, the re-attempt information specified in an equivalent PLMN unit may be information indicating that reconnection using the same information is permitted when the PLMN to be changed is an equivalent PLMN at the time of PLMN change. Also, when the PLMN to be changed is not an equivalent PLMN, it may be information indicating that reconnection using this procedure is not permitted.

[0156] Furthermore, the re-attempt information specified in a mode unit (S1 mode, N1 mode) may be information indicating that reconnection using the same information is permitted when the mode to be changed is the S1 mode at the time of mode change. Also, when the mode to be changed is the S1 mode, it may be information indicating that reconnection using the same information is not permitted.

[0157] A network slice association rule is a rule for associating information for identifying a plurality of network slices. Note that the network slice association rule may be received in a PDU session establishment rejection message, or may be set in UE_A10 in advance. Furthermore, the most recent network slice association rule may be applied in UE_A10. Conversely, UE_A10 may behave based on the latest network slice association rule. For example, when a new network slice association rule is received in a PDU session establishment rejection message while a network slice association rule is set in UE_A10 in advance, UE_A10 may update the network slice association rule held in UE_A10.

[0158] The priority management rule for the backoff timer is a rule set in UE_A10 to manage multiple backoff timers that occur in multiple PDU sessions as one backoff timer. For example, when congestion management with competition or duplication is applied and the UE holds multiple backoff timers, UE_A10 may manage the multiple backoff timers together based on the priority management rule for the backoff timer. Note that the pattern in which competition or overlapping congestion management occurs is when congestion management based only on the DNN and congestion management based on both the DNN and slice information are applied simultaneously. In this case, congestion management based only on the DNN is prioritized. Note that the priority management rule for the backoff timer may not be limited to this. Note that the backoff timer may be the first timer included in the PDU session establishment rejection message.

[0159] The first state is a state in which each device has completed the registration procedure and the PDU session establishment procedure, and UE_A10 and / or each device is in a state in which one or more of the first to fourth congestion managements are applied. Here, UE_A10 and / or each device may be in a state in which UE_A10 is registered with the network (RM-REGISTERED state) due to the completion of the registration procedure, and the completion of the PDU session establishment procedure may be a state in which UE_A10 has received a PDU session establishment rejection message from the network.

[0160] Congestion management is composed of one or more of the first to fourth congestion managements. Note that the control of the UE by the NW is realized by the first timer and the congestion management recognized by the UE, and the UE may memorize the association of these pieces of information.

[0161] The first convergence management refers to control signal convergence management for the parameters of the DNN. For example, in the NW, when convergence for DNN#A is detected and the NW recognizes that it is a UE-initiated session management request targeting only the parameters of DNN#A, the NW may apply the first convergence management. Note that even if the UE-initiated session management request does not contain DNN information, the NW may select a default DNN under its own initiative and use it as the target for convergence management. Alternatively, even when the NW recognizes that it is a UE-initiated session management request including DNN#A and S-NSSAI#A, the NW may apply the first convergence management. When the first convergence management is applied, the UE may suppress a UE-initiated session management request targeting only DNN#A.

[0162] In other words, the first convergence management is control signal convergence management for the DNN, and it may be convergence management resulting from the connectivity to the DNN being in a convergent state. For example, the first convergence management may be convergence management for restricting connections to DNN#A in all connectivities. Here, the connections to DNN#A in all connectivities may be the connections of DNN#A in any connectivity using any S-NSSAI available to the UE, or the connections of DNN#A via a network slice that the UE can connect to. Furthermore, connectivity to DNN#A without going through a network slice may also be included.

[0163] The second convergence management refers to control signal convergence management for the parameters of the S-NSSI. For example, in the NW, when control signal convergence for S-NSSAI#A is detected and the NW recognizes that it is a UE-initiated session management request targeting only the parameters of S-NSSAI#A, the NW may apply the second convergence management. When the second convergence management is applied, the UE may suppress a UE-initiated session management request targeting only S-NSSAI#A.

[0164] In other words, the second convergence management is control signal convergence management for S-NSSAI, and may be convergence management resulting from the network slice selected by the S-NSSAI being in a convergent state. For example, the second convergence management may be convergence management for restricting all connections based on S-NSSAI#A. That is, it may be convergence management for restricting connections to all DNNs via the network slice selected by S-NSSAI#A.

[0165] The third convergence management indicates control signal convergence management for DNN and S-NSSAI parameters. For example, in the NW, when control signal convergence for DNN#A and control signal convergence for S-NSSAI#A are simultaneously detected, and the NW recognizes it as a UE-initiated session management request targeting the parameters of DNN#A and S-NSSAI#A, the NW may apply the third convergence management. Note that even if the UE-initiated session management request does not contain information indicating the DNN, the NW may select a default DNN under its own initiative and also include it as a convergence management target. When the third convergence management is applied, the UE may suppress a UE-initiated session management request targeting the parameters of DNN#A and S-NSSAI#A.

[0166] In other words, the third convergence management is control signal convergence management for DNN and S-NSSAI parameters, and may be convergence management resulting from the connectivity to the DNN via the network slice selected based on the S-NSSAI being in a convergent state. For example, the third convergence management may be convergence management for restricting the connection to DNN#A among the connectivities based on S-NSSAI#A.

[0167] The fourth convergence management refers to control signal convergence management for at least one parameter of the DNN and / or S-NSSAI. For example, in the NW, when the control signal convergence for DNN#A and the control signal convergence for S-NSSAI#A are simultaneously detected, and the NW recognizes that it is a UE-initiated session management request targeting at least one parameter of DNN#A and / or S-NSSAI#A, the NW may apply the fourth convergence management. In addition, even if the information indicating the DNN is not included in the UE-initiated session management request, the NW may select a default DNN under its own initiative and include it as a convergence management target. When the fourth convergence management is applied, the UE may suppress the UE-initiated session management request targeting at least one parameter of DNN#A and / or S-NSSAI#A.

[0168] In other words, the fourth convergence management is control signal convergence management for the parameters of the DNN and S-NSSAI, and may be convergence management resulting from the network slice selected based on the S-NSSAI and the connectivity to the DNN being in a convergent state. For example, the fourth convergence management may be convergence management for regulating all connections based on S-NSSAI#A, and may be convergence management for regulating the connection to DNN#A in all connectivities. That is, it may be convergence management for regulating all connections to all DNNs via the network slice selected by S-NSSAI#A, and may be convergence management for regulating the connection to DNN#A in all connectivities. Here, the connection to DNN#A in all connectivities may be the connection of DNN#A in the connectivity using any S-NSSAI available to the UE, and may be the connection of DNN#A via the network slice to which the UE can connect. Furthermore, the connectivity to DNN#A without passing through the network slice may also be included.

[0169] Therefore, the fourth convergence management with DNN#A and S-NSSAI#A as parameters may be a convergence management that simultaneously executes the first convergence management with DNN#A as a parameter and the second convergence management with S-NSSAI#A as a parameter.

[0170] The first behavior is that the UE stores the slice information transmitted in the first PDU session establishment request message in association with the PDU session identification information. In the first behavior, the UE may store the slice information transmitted in the first PDU session establishment request message, or may store the slice information received when the first PDU session establishment request is rejected.

[0171] The second behavior is that the UE transmits a PDU session establishment request for connecting to the same APN / DNN as the first PDU session establishment request using different slice information from the slice information specified in the first PDU session establishment. Specifically, the second behavior may be that when the backoff timer value received by the UE from the network is zero or invalid, the UE transmits a PDU session establishment request for connecting to the same APN / DNN as the first PDU session establishment request using different slice information from the slice information specified in the first PDU session establishment. Also, when the first PDU session is rejected because the radio access of a specific PLMN to which the specified APN / DNN is connected is not supported, or when the first PDU session is rejected for temporary reasons, the UE may transmit a PDU session establishment request for connecting to the same APN / DNN as the APN / DNN included in the first PDU session establishment request using different slice information from the slice information specified in the first PDU session establishment.

[0172] The third behavior is that when the PDU session establishment request is rejected, the UE does not send a new PDU session establishment request using the same identification information until the first timer expires. Specifically, the third behavior may be that when the backoff timer value received by the UE from the network is neither zero nor invalid, the UE does not send a new PDU session establishment request using the same identification information until the first timer expires. Here, the same identification information may mean that the first identification information and / or the second identification information carried in the new PDU session establishment request is the same as the first identification information and / or the second identification information sent in the rejected PDU session establishment request.

[0173] Also, when another PLMN is selected, or when another NW slice is selected and a rejection reason related to network operation settings is received, and when the backoff timer received when the first PDU session establishment request was rejected is activated, the UE may not send a new PDU session establishment request using the same identification information until the first timer expires.

[0174] Specifically, the PDU session that does not send a new PDU session establishment request in the third behavior may be a PDU session to which congestion management associated with the first timer is applied. More specifically, in the third behavior, it has the connectivity according to the type of congestion management associated with the first timer, and for the PDU session using the DNN and / or S-NSSAI associated with that congestion management, the behavior of not sending a new PDU session establishment request may be adopted. Note that the processes prohibited for the UE by this behavior may be the start of procedures for session management including PDU session establishment requests and / or the transmission and reception of SM messages.

[0175] The fourth behavior is that when the PDU session establishment request is rejected, the UE does not send a new PDU session establishment request without slice information and DNN / APN information until the first timer expires. Specifically, the fourth behavior may be that when the backoff timer received by the UE from the network is neither zero nor invalid, the UE does not send a new PDU session establishment request without slice information and DNN / APN information until the first timer expires.

[0176] The fifth behavior is that when the PDU session establishment request is rejected, the UE does not send a new PDU session establishment request using the same identification information. Specifically, the fifth behavior may be that when the PDP types supported by the UE and the network are different and the UE is in a home PLMN, the UE does not send a new PDU session establishment request using the same identification information.

[0177] The sixth behavior is that when the PDU session establishment request is rejected, the UE sends a new PDU session establishment request as an initial procedure using the same identification information. Specifically, the sixth behavior may be that when the first PDU session establishment request is rejected because there is no target PDN session context in the handover from non-3GPP access, the UE sends a new PDU session establishment request as an initial procedure using the same identification information.

[0178] The seventh behavior is that when the UE selects another NW slice in the procedure of selecting a PLMN, the UE continues the backoff timer received when the previous PDU session establishment request was rejected. Specifically, the seventh behavior may be that when the UE selects a PLMN when the first PDU session establishment request is rejected, and the selected PLMN can specify the same NW slice as the NW slice specified in the first PDU session establishment request, the UE continues the backoff timer received when the first PDU session establishment request was rejected.

[0179] The eighth behavior is the behavior in which the UE sets, as the first timer value, a value notified by the network or a value pre-set in the UE. Specifically, the eighth behavior may be the behavior in which the UE sets, as the first timer value, the backoff timer value received in the rejection notice of the first PDU session establishment request, or may be the behavior in which the UE sets, as the first timer value, a value pre-set or held in the UE. In addition, when setting, as the first timer value, a timer pre-set or held in the UE, it may be limited to when the HPLMN or the equivalent PLMN is in the coverage area.

[0180] The 9th behavior means that when the PDU session establishment request is rejected, the UE does not send a new PDU session establishment request until the terminal power is turned on / off or the USIM (Universal Subscriber Identity Module) is inserted / removed. Specifically, the 9th behavior means that when the backoff timer received from the network is invalid, or when the first PDU session rejection reason is that the PDP type (PDP type) is different between the UE and the network, the UE does not send a new PDU session establishment request until the terminal power is turned on / off or the USIM is inserted / removed. Also, when the first PDU session establishment request is rejected because the specified APN / DNN is not supported wirelessly by the connected PLMN, and there is no backoff timer information element or re-attempt information from the network, or when PDU session reconnection to an equivalent PLMN is allowed, the connected PLMN may also not send a new PDU session establishment request until the terminal power is turned on / off or the USIM is inserted / removed. Also, when the first PDU session establishment request is rejected because the specified APN / DNN is not supported wirelessly by the connected PLMN, and there is no backoff timer information element or re-attempt information from the network, or when PDU session reconnection to an equivalent PLMN is not allowed, the connected PLMN may also not send a new PDU session establishment request until the terminal power is turned on / off or the USIM is inserted / removed. Also, when the first PDU session establishment request is rejected because the specified APN / DNN is not supported wirelessly by the connected PLMN, and the backoff timer from the network is neither zero nor invalid, the UE may also not send a new PDU session establishment request until the terminal power is turned on / off or the USIM is inserted / removed.Also, when the first PDU session establishment request is rejected because the specified APN / DNN is not supported wirelessly by the PLMN to which it is connected, and the backoff timer from the network is invalid, the terminal may not send a new PDU session establishment request until the terminal power is turned on / off or the USIM is inserted / removed.

[0181] The tenth behavior is that the UE sends a new PDU session establishment request when the PDU session establishment request is rejected. Specifically, the tenth behavior may be that the UE sends a new PDU session establishment request when the backoff timer received from the network is zero, or when the first PDU session establishment request is rejected for a temporary reason and there is no backoff timer information element notified from the network. Also, when another PLMN is selected, or when another NW slice is selected, and the first PDU session establishment request is rejected for a temporary reason, and the backoff timer for the target APN / DNN is not started in the selected PLMN, or when the backoff timer received from the network is invalid, the UE may send a new PDU session establishment request. Also, when the first PDU session establishment request is rejected because the PDP types of the UE and the network are different, and when a different PLMN is selected, no Re-attempt information is received, or a PLMN not in the equal PLMN list is selected, or the PDP type is changed, or the terminal power is turned on / off, or the USIM is inserted / removed, the UE may send a new PDU session establishment request. Also, when the first PDU session establishment request is rejected because the specified APN / DNN is not supported wirelessly by the PLMN to which it is connected, and the backoff timer notified from the network is zero, the UE may send a new PDU session establishment request.

[0182] The 11th behavior is that the UE ignores the first timer and the Re-attempt information. Specifically, the 11th behavior may be that when the UE's first PDU session establishment request is rejected because there is no target PDN session context in the handover from non-3GPP access, or when the first PDU session establishment is rejected because the number of bearers established in the PDN connection reaches the maximum allowable number, the UE ignores the first timer and the Re-attempt information.

[0183] The 12th behavior is that the UE determines the information for identifying a plurality of related NW slices based on the information for identifying one NW slice received in the rejection notice for the first PDU session establishment request, and suppresses reconnection to the plurality of related NW slices based on the information for identifying one NW slice. Specifically, the 12th behavior may be that the UE derives the information for identifying another NW slice related to the information for identifying the NW slice notified in the rejection of the first PDU session establishment request based on the network slice association rule. Note that the network slice association rule may be set in the UE in advance, or may be notified from the network in the rejection notice of the PDU session establishment.

[0184] The 13th behavior means that when different multiple congestion managements are activated for the establishment of one or more PDU sessions by the same UE and multiple timers are provided from the network, the UE may manage the timers based on the priority management rules of the backoff timer. For example, the first PDU session establishment request for the combination of DNN_1 and slice_1 by the UE is subject to congestion management based on both DNN and slice information, and the UE receives the first timer #1. Further, when the UE makes a second PDU session establishment request for the combination of DNN_1 and slice_2 and is subject to congestion management based only on the DNN and receives the first timer #2. At this time, based on the priority management rules of the backoff timer, the PDU session re-establishment behavior of the UE may be managed by the optimized first timer #2. Specifically, the value of the timer held by the UE may be overwritten by the timer value generated by the prioritized congestion control.

[0185] The 14th behavior means that when different multiple congestion managements are applied to the establishment of one or more PDU sessions by the same UE and multiple timers are provided from the network, it may be the behavior of managing the timers for each session management instance (per PDU session). For example, when the establishment of the first PDU session for the combination of DNN#1 and slice#1 by the UE is subject to congestion based on both DNN and slice information, the UE manages the target backoff timer value as the first timer #1. Then, further, when the UE attempts to establish a PDU session for the combination of DNN#1 and slice#2 as the second PDU session and is subject to congestion based only on the DNN, the UE manages the target backoff timer value as the first timer #2. At this time, the UE manages multiple timers (here, the first timer #1 and the first timer #2) simultaneously. Specifically, the UE manages the timers in units of session management instances / PDU sessions. Also, when the UE receives multiple timers simultaneously in one session management procedure, the UE manages the target backoff timer simultaneously in the congestion management unit identified by the UE.

[0186] The 15th behavior may be a behavior in which UE_A10 executes a first identification process for identifying which type of convergence management among the first to fourth convergence managements to apply, and a second identification process for identifying a DNN and / or S-NSSAI associated with the applicable convergence management. Note that the first identification process may be identified based on at least one or more pieces of identification information from the first identification information to the fourth identification information, and / or at least one or more pieces of identification information from the 11th identification information to the 18th identification information. Similarly, the second identification process may be identified based on at least one or more pieces of identification information from the first identification information to the fourth identification information, and / or at least one or more pieces of identification information from the 11th identification information to the 18th identification information.

[0187] Hereinafter, an example of the first identification process will be described. In the first identification process, the type of convergence management to be applied may be identified as the first convergence management when any one or a combination of two or more of the following cases is satisfied. · When at least the 15th identification information is a value corresponding to the first convergence management. · When at least the 16th identification information is a value corresponding to the first convergence management. · When at least the 14th identification information contains information indicating the first convergence management. · When at least the 17th identification information contains only DNN and does not contain S-NSSAI. · When the 16th identification information is information for identifying any one of the first convergence management and the second convergence management, and is information that can be set only with a value corresponding to the second convergence management for the 16th identification information, at least when the 16th identification information is not received. · When the 16th identification information is information for identifying any one of the first convergence management and the fourth convergence management, and is information that can be set only with a value corresponding to the fourth convergence management for the 16th identification information, at least when the 16th identification information is not received. · When the 16th identification information is information for identifying any one of the first congestion management, the second congestion management, and the fourth congestion management, and is information in which only a value corresponding to the second congestion management and a value corresponding to the fourth congestion management can be set for the 16th identification information, at least when the 16th identification information is not received.

[0188] However, not limited to the above example, UE_A10 may identify based on at least one or more of the first identification information to the fourth identification information, and / or at least one of the 11th identification information to the 18th identification information, or a combination of two or more identification information.

[0189] In the first identification process, when any one or a combination of two or more of the following cases is satisfied, the type of congestion management to be applied may be identified as the second congestion management. · At least when the 15th identification information is a value corresponding to the second congestion management. · At least when the 16th identification information is a value corresponding to the second congestion management. · At least when the 14th identification information contains information indicating the second congestion management. · At least when only S-NSSAI is included in the 17th identification information and DNN is not included. · When the 16th identification information is information for identifying any one of the first congestion management and the second congestion management, and is information in which only a value corresponding to the first congestion management can be set for the 16th identification information, at least when the 16th identification information is not received. · When the 16th identification information is information for identifying any one of the second congestion management and the third congestion management, and is information in which only a value corresponding to the third congestion management can be set for the 16th identification information, at least when the 16th identification information is not received. · When the 16th identification information is information for identifying any one of the second congestion management, the third congestion management, and the fourth congestion management, and is information in which only values corresponding to the third congestion management and values corresponding to the fourth congestion management can be set for the 16th identification information, when at least the 16th identification information is not received.

[0190] However, not limited to the above example, UE_A10 may identify based on one or more pieces of identification information from at least the 1st identification information to the 4th identification information, and / or one piece of identification information or a combination of two or more pieces of identification information from at least the 11th identification information to the 18th identification information.

[0191] In the first identification process, the type of congestion management to be applied when any one or a combination of two or more of the following cases is satisfied may be identified as the third congestion management. · When at least the 15th identification information is a value corresponding to the third congestion management. · When at least the 16th identification information is a value corresponding to the third congestion management. · When at least the 14th identification information includes information indicating the third congestion management. · When at least the 15th identification information is a value corresponding to a plurality of congestion managements that include the third congestion management and do not include the fourth congestion management, and the 17th identification information includes S-NSSAI and DNN. · When the 16th identification information is information for identifying any one of the second congestion management and the third congestion management, and is information in which only a value corresponding to the fourth congestion management can be set for the 16th identification information, when at least the 16th identification information is not received. · When the 16th identification information is information for identifying any one of the second congestion management and the third congestion management, and is information in which only a value corresponding to the second congestion management can be set for the 16th identification information, when at least the 16th identification information is not received. · When the 16th identification information is information for identifying any one of the second congestion management, the third congestion management, and the fourth congestion management, and is information in which only values corresponding to the second congestion management and values corresponding to the fourth congestion management can be set for the 16th identification information, when at least the 16th identification information is not received.

[0192] However, not limited to the above example, UE_A10 may identify based on one or more pieces of identification information from at least the 1st identification information to the 4th identification information, and / or one piece of identification information or a combination of two or more pieces of identification information from at least the 11th identification information to the 18th identification information.

[0193] In the first identification process, when any one or a combination of two or more of the following cases is satisfied, the type of congestion management to be applied may be identified as the fourth congestion management. · When at least the 15th identification information is a value corresponding to the fourth congestion management. · When at least the 16th identification information is a value corresponding to the fourth congestion management. · When at least the 14th identification information contains information indicating the fourth congestion management. · When at least the 15th identification information is a value corresponding to a plurality of congestion managements that include the fourth congestion management and do not include the third congestion management, and the 17th identification information contains S-NSSAI and DNN. · When the 16th identification information is information for identifying any one of the third congestion management and the fourth congestion management, and is information in which only a value corresponding to the third congestion management can be set for the 16th identification information, when at least the 16th identification information is not received. · When the 16th identification information is information for identifying any one of the second congestion management and the fourth congestion management, and is information in which only a value corresponding to the second congestion management can be set for the 16th identification information, when at least the 16th identification information is not received. · When the 16th identification information is information for identifying any one of the identification information of the first congestion management and the fourth congestion management, and is information in which only a value corresponding to the first congestion management can be set for the 16th identification information, when at least the 16th identification information is not received. · When the 16th identification information is information for identifying any one of the identification information of the second congestion management, the third congestion management, and the fourth congestion management, and is information in which only a value corresponding to the second congestion management and a value corresponding to the third congestion management can be set for the 16th identification information, when at least the 16th identification information is not received. · When the 16th identification information is information for identifying any one of the identification information of the first congestion management, the second congestion management, and the fourth congestion management, and is information in which only a value corresponding to the first congestion management and a value corresponding to the second congestion management can be set for the 16th identification information, when at least the 16th identification information is not received.

[0194] However, not limited to the above examples, UE_A10 may identify based on at least one or more of the identification information from the first identification information to the fourth identification information, and / or at least one of the identification information from the 11th identification information to the 18th identification information, or a combination of two or more pieces of identification information, or may identify using other means.

[0195] As described above, the type of congestion management may be identified by the first identification process.

[0196] Next, an example of the second identification process will be described. Note that the second identification process may be a process of identifying the corresponding DNN and / or S-NSSAI for the type of congestion management identified by the first identification process.

[0197] More specifically, the DNNs corresponding to the first convergence management, the third convergence management, and the fourth convergence management may be determined based on the twelfth identification information. And / or, the DNNs corresponding to the first convergence management, the third convergence management, and the fourth convergence management may be determined based on the seventeenth identification information. And / or, the DNNs corresponding to the first convergence management, the third convergence management, and the fourth convergence management may be determined based on the second identification information.

[0198] Therefore, the DNNs corresponding to the first convergence management, the third convergence management, and the fourth convergence management may be the DNNs indicated by the twelfth identification information. And / or, the DNNs corresponding to the first convergence management, the third convergence management, and the fourth convergence management may be the DNNs included in the seventeenth identification information. And / or, the DNNs corresponding to the first convergence management, the third convergence management, and the fourth convergence management may be the DNNs indicated by the second identification information.

[0199] Also, the S-NSSAIs corresponding to the second convergence management, the third convergence management, and the fourth convergence management may be determined based on the seventeenth identification information. And / or, the DNNs corresponding to the first convergence management, the third convergence management, and the fourth convergence management may be determined based on the first identification information.

[0200] Therefore, the DNNs corresponding to the first convergence management, the third convergence management, and the fourth convergence management may be the S-NSSAIs indicated by the seventeenth identification information. And / or, the DNNs corresponding to the first convergence management, the third convergence management, and the fourth convergence management may be the S-NSSAIs included in the first identification information.

[0201] However, not limited to the above examples, UE_A10 may be identified based on at least one or more of the first identification information to the fourth identification information, and / or at least one of the eleventh identification information to the eighteenth identification information, or a combination of two or more identification information, or may be identified using other means.

[0202] Based on the above 15th behavior, UE_A10 may identify the congestion management applied by core network_B190 to UE_A10. In other words, based on the 15th behavior, UE_A10 may identify, as the congestion management to be applied, the corresponding type of congestion management and the corresponding S-NSSAI and / or DNN. Note that UE_A10 may store and manage one or more pieces of identification information from the 1st to the 4th identification information and from the 11th to the 18th identification information in association with the congestion management to be applied. Here, the 3rd identification information, and / or the 4th identification information, and / or the 13th identification information may be stored and managed as information for identifying the congestion management to be applied.

[0203] The 16th behavior is the behavior of stopping the 1st timer when the NW-led session management procedure is executed while the UE has the 1st timer started.

[0204] Here, for example, when a plurality of 1st timers are started, based on the 21st identification information, among the plurality of 1st timers that are started, the 1st timer to be stopped may be determined and stopped. And / or it may be the behavior of stopping the 1st timer associated with the congestion management identified by the 17th behavior. If there are a plurality of congestion managements identified by the 17th behavior, the timers associated with each congestion management may be stopped respectively.

[0205] The 17th behavior may be the behavior of the UE to identify, among one or more congestion managements applied by the UE, the congestion management whose application is to be stopped based on the reception of a control message sent by the core network. For example, the UE may identify the congestion management whose application is to be stopped or changed based on the 21st identification information.

[0206] Specifically, as described above, the UE stores, as information for identifying congestion management, the third identification information, and / or the fourth identification information, and / or the thirteenth identification information, etc. in the fourth process, and may identify, as the congestion management for stopping application, the congestion management in which the identification information for identifying the congestion management matches the thirteenth identification information included in the twenty-first identification information.

[0207] And / or, the UE may identify the congestion management for stopping application based on one or a combination of a plurality of the eleventh identification information to the eighteenth identification information included in the twenty-first identification information. Here, the details of the identification method may be the same as the identification process in the fifteenth behavior described in the fourth process in the PDU session establishment procedure example described later. That is, the UE may identify the congestion management to be stopped by the same method as the method for identifying the congestion management to be applied.

[0208] In addition, the UE may identify a plurality of congestion managements for stopping application. Hereinafter, the method for identifying the second congestion management different from the first congestion management, where the first congestion management is the congestion management identified by the method described above, will be described.

[0209] For example, the UE may identify, as the second congestion management, the congestion management associated with the same DNN as the DNN associated with the first congestion management. And / or, the UE may identify, as the second congestion management, the congestion management associated with the same S-NSSAI as the S-NSSAI associated with the first congestion management. In addition, the identification of a plurality of congestion managements for stopping application may be set to be executed only when the first congestion management and / or the second congestion management is a specific type of congestion management.

[0210] Specifically, in any of the first to fourth convergence managements, the UE may identify the second convergence management. And / or, when identifying the second convergence management, in the case where the convergence management to be searched for is any of the first to fourth convergence managements, the UE may identify the second convergence management. Note that the type of the first convergence management and / or the second identification information in which a plurality of convergence managements can be identified may be set in advance in the core network and / or the UE. Note that the type of the specific convergence management for which identification is allowed does not have to be specified uniquely and may be set in plural.

[0211] The first identification information is information for identifying belonging to the first NW slice. In other words, the first identification information may be information indicating that the UE desires to establish a PDU session belonging to the first NW slice. Specifically, for example, the first identification information may be information for identifying the first NW slice. Note that the slice information may be identification information indicating a specific S-NSSAI. Note that the first identification information may be information for identifying a specific NW slice within the operator A network, or may be information for commonly identifying the same NW slice even within operator B (other operators other than operator A). Furthermore, the first identification information may be information for identifying the first NW slice set from the HPLMN, or may be information for identifying the first NW slice acquired from the AMF in the registration procedure, or may be information for identifying the first NW slice permitted by the network. Furthermore, the first identification information may be information for identifying the first NW slice stored for each PLMN.

[0212] The second identification information is a DNN (Data Network Name), and may be information used to identify a DN (Data Network).

[0213] The third identification information may be a PDU Session ID, which is information used to identify a PDU Session.

[0214] The fourth identification information is a PTI (Procedure transaction identity), which is information that identifies a series of messages for a specific session management procedure as one group, and may further be information used to identify and / or distinguish the transmission and reception of another series of session management related messages.

[0215] The eleventh identification information may be information indicating the rejection of a request for PDU session establishment or a request for PDU session modification. Note that the request for PDU session establishment or the request for PDU session modification is a request made by the UE and includes a DNN and / or an S-NSSAI. That is, the eleventh identification information may be information indicating that the NW rejects the establishment request or the modification request for the PDU session corresponding to these DNNs and / or S-NSSAs.

[0216] Also, the eleventh identification information may be information indicating re-attempt information.

[0217] Further, the NW may indicate congestion management to the UE by transmitting at least one of the 12th to 18th identification information to the UE together with the 11th identification information. In other words, the NW may notify the UE of congestion management corresponding to one or a combination of a plurality of the 12th to 18th identification information. On the other hand, the UE may identify congestion management corresponding to one or a combination of a plurality of the 12th to 18th identification information and execute processing based on the identified congestion management. Specifically, the UE may start counting the first timer associated with the identified congestion management. Note that the timer value of the first timer may be determined using the 14th identification information, or may be set to a timer value set by another method such as using a value previously stored by the UE, or may be set to a random value.

[0218] The 12th identification information may be a DNN that the network has not permitted, or may be information indicating that the DNN identified by the second identification information is not permitted. Further, the 12th identification information may be the same DNN as the second identification information.

[0219] The 13th identification information is a PDU Session ID and / or a PTI, and may be a PDU session ID and / or a PTI that the network has not permitted, or may be information indicating that the PDU session ID and / or the PTI identified by the third identification information is not permitted. Further, the PDU Session ID of the 13th identification information may be the same PDU session ID as the third identification information. Also, the PTI of the 13th identification information may be the same PTI as the fourth identification information.

[0220] Here, the 13th identification information may be used as information for identifying the congestion management that the NW notifies the UE based on the rejection of PDU session establishment. In other words, the UE may store and manage the 13th identification information in association with the congestion management executed based on the 15th behavior, and use it as information for identifying the executed congestion management. Note that the information for identifying the congestion management may be constituted by a combination of one or more pieces of identification information from the 14th to the 18th identification information in addition to the 13th identification information.

[0221] The 14th identification information may be information indicating the value of the backoff timer. In other words, the backoff timer may be a value indicating the validity period of the congestion management that the NW notifies the UE based on the rejection of PDU session establishment. In other words, in the 15th behavior that the UE executes upon receiving the 14th identification information, the UE may use the 14th identification information as the value of the timer. Further, the 14th identification information may include information for identifying the type of congestion management in addition to the timer value. Specifically, it may include information for identifying which congestion management among the 1st to the 4th congestion managements it is. For example, the information for identifying the congestion management type may be the timer name for identifying each congestion management, or may be a flag for identifying each congestion management. Not limited to this, it may be identified by other methods such as being identified by the position stored in the control message.

[0222] The 15th identification information is information indicating one or more cause values indicating the reason why this procedure was rejected. In other words, the cause value may be information indicating the congestion management applied by the NW to this procedure, or may be information indicating the cause value for rejecting this procedure applied by the NW other than the congestion management.

[0223] Alternatively, the cause value may be information for identifying which congestion management among the first to fourth congestion managements is indicated by the congestion management that the NW notifies the UE based on the rejection of the PDU session establishment. In this case, the NW may send different values to the UE as the cause value according to each of the first to fourth congestion managements. The UE may grasp in advance the meaning of each value sent as the cause value, and in the 15th behavior, may identify which congestion management among the first to fourth congestion managements based on at least the 15th identification information.

[0224] Alternatively, the cause value may be information for identifying whether the congestion management that the NW notifies the UE based on the rejection of the PDU session establishment is the first congestion management or any one of the second, third, and fourth congestion managements. In this case, the NW may send different values to the UE as the cause value according to whether it is the first congestion management or any one of the second, third, and fourth congestion managements. The UE may grasp in advance the meaning of each value sent as the cause value, and in the 15th behavior, may identify whether it is the first congestion management or the second, third, and fourth congestion managements based on at least the 15th identification information.

[0225] Alternatively, the cause value may be information for identifying whether the congestion management that the NW notifies the UE based on the rejection of the PDU session establishment is the first congestion management, the second congestion management, or any one of the third and fourth congestion managements. In this case, the NW may send different values to the UE as the cause value according to whether it is the first congestion management, the second congestion management, or any one of the third and fourth congestion managements. The UE may grasp in advance the meaning of each value sent as the cause value, and in the 15th behavior, may identify whether it is the first congestion management, the second congestion management, or any one of the third and fourth congestion managements based on at least the 15th identification information.

[0226] Alternatively, the cause value may be information for identifying whether the congestion management that the NW notifies the UE based on the rejection of PDU session establishment is the first congestion management or the second congestion management, or the third congestion management or the fourth congestion management. In this case, depending on whether it is the first congestion management or the second congestion management, or the third congestion management or the fourth congestion management, the NW may send different values to the UE as the cause value. The UE grasps in advance the meaning of each value sent as the cause value, and in the 15th behavior, may identify whether it is the first congestion management or the second congestion management, or the third congestion management or the fourth congestion management based at least on the 15th identification information.

[0227] Alternatively, the cause value may be information for identifying whether the congestion management that the NW notifies the UE based on the rejection of PDU session establishment is the second congestion management or the third congestion management, or the first congestion management or the fourth congestion management. In this case, depending on whether it is the second congestion management or the third congestion management, or the first congestion management or the fourth congestion management, the NW may send different values to the UE as the cause value. The UE grasps in advance the meaning of each value sent as the cause value, and in the 15th behavior, may identify whether it is the second congestion management or the third congestion management, or the first congestion management or the fourth congestion management based at least on the 15th identification information.

[0228] Alternatively, the cause value may be information for identifying whether the congestion management that the NW notifies the UE based on the rejection of PDU session establishment is the second congestion management or the fourth congestion management, or the first congestion management or the third congestion management. In this case, depending on whether it is the second congestion management or the fourth congestion management, or the first congestion management or the third congestion management, the NW may send different values to the UE as the cause value. The UE grasps in advance the meaning of each value sent as the cause value, and in the 15th behavior, may identify whether it is the second congestion management or the fourth congestion management, or the first congestion management or the third congestion management based at least on the 15th identification information.

[0229] Alternatively, the cause value may be information indicating that the NW performs congestion management on the UE based on the rejection of PDU session establishment. In other words, the cause value may be information for causing the UE to execute any one of the fourth congestion management from the first congestion management. In this case, the cause value may not be information that can identify a specific congestion management.

[0230] Furthermore, as a more detailed example of the reason value for rejecting the present procedure applied by an NW other than the aforementioned convergence management, the reason value that an NW notifies the UE indicating that the external DN has rejected the present procedure on the grounds that the DNN information is not included in or is an unknown DNN in the present procedure may be (Missing or unknown DNN). Also, the reason value that an NW notifies the UE indicating that the external DN has rejected the present procedure on the grounds that the PDU session type of the present procedure is unidentifiable or not permitted may be (Unknown PDU session type). Also, the reason value that an NW notifies the UE indicating that the external DN has rejected the present procedure on the grounds of failure of user authentication and authorization in the present procedure, or invalidation of authentication and authorization by the external DN, or invalidation of authentication and authorization by the NW may be (User authentication or authorization failed). Also, it may be the reason value that the NW notifies the UE that the service, operation, or resource reservation request requested based on unspecified reasons has been rejected (Request rejected, unspecified). Also, it may be the reason value that the NW notifies the UE that it cannot temporarily receive the service request from the UE (Service option temporarily out of order). Also, it may be the reason value that the NW notifies the UE that the PTI inserted by the UE is already in use (PTI already in use). Also, it may be the reason value that the NW notifies the UE that the UE is outside the LADN service area (Out of LADN service area). Also, it may be the reason value that the NW notifies the UE that only the PDU session type IPv4 is permitted (PDU session type IPv4 only allowed). Also, it may be the reason value that the NW notifies the UE that only the PDU session type IPv6 is permitted (PDU session type IPv6 only allowed).Also, when the NW notifies the UE of a cause value indicating that the NW does not hold the target PDU session when the UE moves the PDU session from non-3GPP access to 3GPP access or from EPS to 5GS (PDU session does not exist). Also, when the NW notifies the UE of a cause value indicating that the NW does not support the SSC mode requested by the UE (Not supported SSC mode). Also, when the external DN rejects this procedure on the grounds that the DNN information is not included in or is unknown for a specific slice in this procedure, the NW may notify the UE of a cause value indicating this (Missing or unknown DNN in a slice). Also, when the NW notifies the UE of a cause value indicating that the UE does not meet the requirement for the maximum data transfer rate for ensuring user plane confidentiality required in the service requested by the UE (Maximum data rate per UE for user-plane integrity protection is too low).

[0231] In addition, when the third congestion management is not executed, the meaning corresponding to the third congestion management in the cause value with the above-mentioned 15th identification information is unnecessary, and the cause value with the 15th identification information may be one that omits the processing, explanation, and meaning regarding the third congestion management from the above description. Also, when the fourth congestion management is not executed, the meaning corresponding to the fourth congestion management in the cause value with the above-mentioned 15th identification information is unnecessary, and the cause value with the 15th identification information may be one that omits the processing, explanation, and meaning regarding the fourth congestion management from the above description.

[0232] As a more detailed example, the 15th identification information for identifying the first congestion management may be a reason value indicating that resources are insufficient (Insufficient resources). Also, the 15th identification information for identifying the second congestion management may be a reason value indicating that resources for a specific slice are insufficient (Insufficient resources for specific slice). Further, the 15th identification information for identifying the third congestion management may be a reason value indicating that resources for a specific slice and DNN are insufficient (Insufficient resources for specific slice and DNN).

[0233] Thus, the 15th identification information may be information capable of identifying the type of congestion management. Furthermore, the backoff timer and / or backoff timer value indicated by the 14th identification information may be information indicating which type of congestion management it corresponds to.

[0234] Therefore, UE_A10 may identify the type of congestion management based on the 15th identification information. Furthermore, based on the 15th identification information, it may also determine which type of congestion management the backoff timer and / or backoff timer value indicated by the 14th identification information corresponds to.

[0235] The 16th identification information is one or more identifier (Indication) information indicating that this procedure has been rejected. In other words, the Indication information may be information indicating the congestion management applied by the NW to this procedure. The NW may indicate the congestion management applied by the NW based on the 16th identification information.

[0236] For example, the Indication information may be information indicating which of the first to fourth congestion managements the NW restricts the UE from performing. Therefore, the NW may transmit, as the Indication information, a value associated with the restriction management applied to the UE. The UE grasps in advance the meaning of each value transmitted as the Indication information, and in the fifteenth behavior, may identify which of the first to fourth congestion managements it is based on at least the sixteenth identification information. Here, two or more of the first to fourth congestion managements refer to congestion managements that can be identified using the Indication information, and the congestion management to be identified may be all four congestion managements, or may be the first and second congestion managements, or the third and fourth congestion managements, or the second to fourth congestion managements, or any other arbitrary combination.

[0237] In addition, the Indication information does not necessarily require values corresponding to all of the congestion managements to be identified. For example, if values of the Indication information are associated and assigned to each of the congestion managements excluding congestion management A, it is not necessarily required to set a value of the Indication information for congestion management A. In this case, the NW and the UE can identify that it is the first congestion management because the Indication information is not transmitted and received. Note that congestion management A may be any of the first to fourth congestion managements.

[0238] Also, when notifying the UE of congestion management based on the transmission of a PDU session establishment rejection message, there may be cases where Identification is included or not included depending on the type of congestion management of the first to fourth congestion managements. In other words, the NW may use the Identification information as information indicating the congestion management according to the type of congestion management, or may use other identification information as information indicating the congestion management without using the Identification information depending on the type of congestion management.

[0239] Also, when not performing the third congestion management, the meaning corresponding to the third congestion management in the Indication information with the above-described 16th identification information is unnecessary, and the Indication information with the 16th identification information may omit the processing, description, and meaning regarding the third congestion management from the above description. Further, when not performing the fourth congestion management, the meaning corresponding to the fourth congestion management in the Indication information with the above-described 16th identification information is unnecessary, and the Indication information with the 16th identification information may omit the processing, description, and meaning regarding the fourth congestion management from the above description.

[0240] The 17th identification information is one or more Value information indicating that this procedure has been rejected. In other words, the Value information may be information indicating the congestion management applied by the NW to this procedure. Also, the 17th identification information may include identification information for identifying one or more NW slices included in the 18th identification information, and / or at least one of the 12th identification information.

[0241] The NW may indicate the congestion management applied by the NW based on the 17th identification information. In other words, the NW may indicate which congestion management among the first to fourth congestion managements has been applied based on the 17th identification information. Further, the NW may indicate the DNN and / or S-NSSAI that is the target of the congestion management applied to the UE based on the transmission of the PDU session establishment rejection message based on the 17th identification information. For example, when the 17th identification information is only DNN#1, it may indicate that the first congestion management targeting DNN#1 has been applied. When the 17th identification information is only S-NSSAI#1, it may indicate that the second congestion management targeting S-NSSAI#1 has been applied. When the 17th information is composed of DNN#1 and S-NSSAI#1, it may indicate that the third congestion management, or the fourth congestion management targeting at least one of DNN#1 and / or S-NSSAI#1 has been applied.

[0242] Furthermore, the 17th identification information does not necessarily have to be information that can identify which congestion management from the first to the fourth congestion management is applied. The 17th identification information may be information indicating a DNN and / or S-NSSAI that is the target of congestion management identified by other means, such as being identified based on other identification information.

[0243] The 18th identification information may be information indicating that a request for establishment of a PDU session belonging to the first NW slice has been rejected, or may be information indicating that a request for establishment of a PDU session belonging to the first NW slice, or a PDU session change (PDU session modification), has not been permitted. Here, the first NW slice may be the NW slice determined by the first identification information, or may be a different NW slice. Furthermore, the 18th identification information may be information indicating that establishment of a PDU session belonging to the first NW slice is not permitted in the DN identified by the 12th identification information, or may be information indicating that establishment of a PDU session belonging to the first NW slice is not permitted in the PDU session identified by the 13th identification information. Furthermore, the 11th identification information may be information indicating that establishment of a PDU session belonging to the first slice is not permitted in the registration area and / or tracking area to which UE_A10 currently belongs, or may be information indicating that establishment of a PDU session belonging to the first NW slice is not permitted in the access network to which UE_A10 is connected. Furthermore, the 11th identification information may be identification information for identifying one or more NW slices that identify the NW slice to which the rejected PDU session request belongs. Furthermore, the 18th identification information may be identification information indicating auxiliary information for the radio access system to select an appropriate MME when the UE switches the connection destination to EPS. Note that the auxiliary information may be information indicating a DCN ID. Furthermore, the 18th identification information may be a network slice association rule that is a rule for associating multiple slice information.

[0244] The 21st identification information may be information for stopping one or more first timers that the UE has started, or may be information indicating the first timer to be stopped among the first timers that the UE has started. Specifically, the 21st identification information may be information indicating the 13th identification information that the UE stores in association with the first timer. Further, the 21st identification information may be information indicating at least one of the 12th to 18th identification information that the UE stores in association with the first timer.

[0245] Furthermore, the 21st identification information may be information for changing the association between the first timer that the UE stores and the information indicating at least one of the 13th to 17th identification information. For example, when the UE receives a network-initiated session management request including the 21st identification information for permitting a connection to DNN#A while a first timer for suppressing UE-initiated session management for the combination of DNN#A and S-NSSAI#A is running, the UE may change the association target of the running timer only to S-NSSAI#A and recognize that the UE-initiated session management request to DNN#A has been permitted. In other words, the 21st identification information may be information indicating that the congestion management applied at the time of receiving the 21st identification information is changed to another congestion management among the first to fourth congestion managements.

[0246] Next, the initial procedure will be described with reference to FIG. 9. Hereinafter, the initial procedure is also referred to as this procedure, and this procedure includes a registration procedure, a UE-initiated PDU session establishment procedure, and a network-initiated session management procedure. Details of the registration procedure, the PDU session establishment procedure, and the network-initiated session management procedure will be described later.

[0247] Specifically, by executing the registration procedure (S900), each device causes UE_A10 to transition to a state registered with the network (RM-REGISTERED state). Next, by executing the PDU session establishment procedure (S902), each device causes UE_A10 to establish a PDU session with DN_A5 that provides a PDU connection service via core network_B190, and each device transitions to a first state (S904). Note that this PDU session is assumed to be established via an access network and UPF_A235, but is not limited thereto. That is, a UPF different from UPF_A235 (UPF_C239) may exist between UPF_A235 and the access network. At this time, this PDU session will be established via the access network, UPF_C239, and UPF_A235. Next, each device in the first state may execute a session management procedure at an arbitrary timing (S906). Here, the session management procedure may be a network-initiated session management procedure or a UE-initiated session management procedure.

[0248] Note that each device may exchange various capability information and / or various request information of each device in the registration procedure and / or the PDU session establishment procedure and / or the network-initiated session management procedure. Further, when each device performs the exchange of various information and / or the negotiation of various requests in the registration procedure, the exchange of various information and / or the negotiation of various requests may or may not be performed in the PDU session establishment procedure and / or the network-initiated session management procedure. Further, when each device does not perform the exchange of various information and / or the negotiation of various requests in the registration procedure, the exchange of various information and / or the negotiation of various requests may be performed in the PDU session establishment procedure and / or the network-initiated session management procedure. Further, even when each device performs the exchange of various information and / or the negotiation of various requests in the registration procedure, the exchange of various information and / or the negotiation of various requests may be performed in the PDU session establishment procedure and / or the network-initiated session management procedure.

[0249] Also, each device may execute the PDU session establishment procedure either during the registration procedure or after the completion of the registration procedure. Further, when the PDU session establishment procedure is executed during the registration procedure, the PDU session establishment request message may be included in and transmitted / received with the registration request message, the PDU session establishment acceptance message may be included in and transmitted / received with the registration acceptance message, the PDU session establishment completion message may be included in and transmitted / received with the registration completion message, and the PDU session establishment rejection message may be included in and transmitted / received with the registration rejection message. Also, when the PDU session establishment procedure is executed during the registration procedure, each device may establish a PDU session based on the completion of the registration procedure, or may transition to a state where the PDU session is established between the devices.

[0250] Also, each device involved in this procedure may transmit and receive one or more pieces of identification information included in each control message by transmitting and receiving each control message described in this procedure, and may store each transmitted and received piece of identification information as a context.

[0251] [1.3.1. Overview of the Registration Procedure] First, an overview of the registration procedure will be described. The registration procedure is a procedure for UE_A10 to register with the network (access network and / or core network_B190 and / or DN_A5) under its own initiative. If UE_A10 is not registered with the network, it can execute this procedure at any timing such as when power is turned on. In other words, UE_A10 may start this procedure at any timing if it is in the non-registered state (RM-DEREGISTERED state). Also, each device may transition to the registered state (RM-REGISTERED state) based on the completion of the registration procedure.

[0252] Furthermore, this procedure may be a procedure for updating the location registration information of UE_A10 in the network, and / or for periodically notifying the network of the status of UE_A10 from UE_A10, and / or for updating specific parameters related to UE_A10 in the network.

[0253] UE_A10 may start this procedure when it has mobility across TAs. In other words, UE_A10 may start this procedure when it moves to a TA different from the TA indicated in the TA list it holds. Furthermore, UE_A10 may start this procedure when the timer it is running expires. Furthermore, UE_A10 may start this procedure when the context of each device needs to be updated due to the disconnection or inactivation (also referred to as deactivation) of a PDU session. Furthermore, UE_A10 may start this procedure when there is a change in the capability information and / or preference regarding the establishment of the PDU session of UE_A10. Furthermore, UE_A10 may start this procedure periodically. Note that UE_A10 is not limited to these, and as long as the PDU session is established, it can execute this procedure at any timing.

[0254] [1.3.1.1. Example of Registration Procedure] Using FIG. 10, an example of the procedure for executing the registration procedure will be described. In this chapter, this procedure refers to the registration procedure. Hereinafter, each step of this procedure will be described.

[0255] First, UE_A10 starts the registration procedure by sending a Registration Request message to AMF_A240 via NR node (also referred to as gNB)_A122 and / or ng-eNB (S1000)(S1002)(S1004). Also, UE_A10 may start procedures for session management (SM), such as PDU session establishment procedures, during the registration procedure by including an SM message (e.g., PDU session establishment request message) in the registration request message and sending it, or by sending an SM message (e.g., PDU session establishment request message) together with the registration request message.

[0256] Specifically, UE_A10 sends an RRC (Radio Resource Control) message containing the registration request message to NR node_A122 and / or ng-eNB (S1000). When NR node_A122 and / or ng-eNB receives the RRC message containing the registration request message, it extracts the registration request message from the RRC message and selects AMF_A240 as the NF or shared CP function to which the registration request message is routed (S1002). Here, NR node_A122 and / or ng-eNB may select AMF_A240 based on the information contained in the RRC message. NR node_A122 and / or ng-eNB sends or forwards the registration request message to the selected AMF_A240 (S1004).

[0257] Note that the registration request message is a NAS (Non-Access-Stratum) message transmitted and received on the N1 interface. Also, the RRC message is a control message transmitted and received between UE_A10 and NR node_A122 and / or ng-eNB. Further, the NAS message is processed at the NAS layer, the RRC message is processed at the RRC layer, and the NAS layer is a layer higher than the RRC layer.

[0258] Also, when there are multiple NSIs for which registration is requested, UE_A10 may send a registration request message for each such NSI, or may include multiple registration request messages in one or more RRC messages and send them. Further, the above multiple registration request messages may be included in one or more RRC messages as one registration request message and sent.

[0259] When AMF_A240 receives a registration request message and / or a control message different from the registration request message, it performs a first condition determination. The first condition determination is for determining whether AMF_A240 accepts the request of UE_A10. In the first condition determination, AMF_A240 determines whether the first condition determination is true or false. If the first condition determination is true (i.e., the network accepts the request of UE_A10), AMF_A240 starts the procedure of (A) during this procedure; if the first condition determination is false (i.e., the network does not accept the request of UE_A10), AMF_A240 starts the procedure of (B) during this procedure.

[0260] The steps when the first condition determination is true, i.e., each step of the procedure (A) in this procedure, will be described below. AMF_A240 performs the fourth condition determination and starts the procedure (A) in this procedure. The fourth condition determination is for determining whether AMF_A240 performs the transmission and reception of SM messages with SMF_A230. In other words, the fourth condition determination may be for determining whether AMF_A240 performs the PDU session establishment procedure during this procedure. When the fourth condition determination is true (i.e., when AMF_A240 performs the transmission and reception of SM messages with SMF_A230), AMF_A240 selects SMF_A230 and performs the transmission and reception of SM messages with the selected SMF_A230. When the fourth condition determination is false (i.e., when AMF_A240 does not perform the transmission and reception of SM messages with SMF_A230), those are omitted (S1006). Note that when AMF_A240 receives an SM message indicating rejection from SMF_A230, it may terminate the procedure (A) in this procedure and start the procedure (B) in this procedure.

[0261] Furthermore, based on receiving the registration request message from UE_A10 and / or completing the transmission and reception of SM messages with SMF_A230, AMF_A240 transmits a Registration Accept message to UE_A10 via NR node_A122 (S1008). For example, when the fourth condition determination is true, AMF_A240 may transmit a registration acceptance message based on receiving the registration request message from UE_A10. Also, when the fourth condition determination is false, AMF_A240 may transmit a registration acceptance message based on completing the transmission and reception of SM messages with SMF_A230. Here, the registration acceptance message may be transmitted as a response message to the registration request message. Also, the registration acceptance message is a NAS message transmitted and received on the N1 interface. For example, AMF_A240 transmits it as a control message on the N2 interface to NR node_A122, and NR node_A122 that has received this may include it in an RRC message and transmit it to UE_A10.

[0262] Furthermore, when the fourth condition determination is true, AMF_A240 may include an SM message (for example, a PDU session establishment acceptance message) in the registration acceptance message and transmit it, or transmit an SM message (for example, a PDU session establishment acceptance message) together with the registration acceptance message. This transmission method may be executed when an SM message (for example, a PDU session establishment request message) is included in the registration request message and the fourth condition determination is true. Also, this transmission method may be executed when an SM message (for example, a PDU session establishment request message) is included together with the registration request message and the fourth condition determination is true. By performing such a transmission method, AMF_A240 may indicate that the procedure for SM has been accepted.

[0263] UE_A10 receives a registration acceptance message via the NR node_A122 (S1008). By receiving the registration acceptance message, UE_A10 recognizes the content of various identification information included in the registration acceptance message.

[0264] Next, based on the reception of the registration acceptance message, UE_A10 sends a Registration Complete message to AMF_A240 (S1010). In addition, when UE_A10 receives an SM message such as a PDU session establishment acceptance message, it may include the SM message such as the PDU session establishment complete message in the registration complete message and send it, or including the SM message may indicate that the procedure for SM is completed. Here, the registration complete message may be sent as a response message to the registration acceptance message. Also, the registration complete message is a NAS message transmitted on the N1 interface. For example, UE_A10 may include it in an RRC message and send it to the NR node_A122, and the received NR node_A122 may send it to AMF_A240 as a control message on the N2 interface.

[0265] AMF_A240 receives the registration complete message (S1010). Also, each device completes the procedure (A) during this procedure based on the transmission and reception of the registration acceptance message and / or the registration complete message.

[0266] Next, the steps when the first condition determination is false, i.e., each step of the procedure (B) in this procedure, will be described. AMF_A240 starts the procedure (B) in this procedure by sending a Registration Reject message to UE_A10 via NR node_A122 (S1012). Here, the Registration Reject message may be sent as a response message to the Registration Request message. Also, the Registration Reject message is a NAS message transmitted and received on the N1 interface. For example, AMF_A240 may send it as a control message on the N2 interface to NR node_A122, and NR node_A122 that has received this may include it in an RRC message and send it to UE_A10. Also, the Registration Reject message sent by AMF_A240 is not limited to this as long as it is a message that rejects the request of UE_A10.

[0267] In addition, the procedure (B) in this procedure may be started when the procedure (A) in this procedure is aborted. In the procedure (A), when the fourth condition determination is true, AMF_A240 may include in the Registration Reject message an SM message indicating rejection such as a PDU session establishment rejection message, or by including an SM message indicating rejection, it may indicate that the procedure for SM has been rejected. In that case, UE_A10 may further receive an SM message indicating rejection such as a PDU session establishment rejection message, or may recognize that the procedure for SM has been rejected.

[0268] Furthermore, UE_A10 may recognize that the request of UE_A10 has been rejected by receiving the Registration Reject message or by not receiving the Registration Accept message. Each device completes the procedure (B) in this procedure based on the transmission and reception of the Registration Reject message.

[0269] Each device completes this procedure (registration procedure) based on the completion of procedure (A) or (B) during this procedure. Note that each device may transition to a state where UE_A10 is registered with the network (RM_REGISTERED state) based on the completion of procedure (A) during this procedure, or may maintain a state where UE_A10 is not registered with the network (RM_DEREGISTERED state) based on the completion of procedure (B) during this procedure. Also, the transition of each device to each state may be performed based on the completion of this procedure, or may be performed based on the establishment of a PDU session.

[0270] Furthermore, each device may perform processing based on the identification information transmitted and received in this procedure based on the completion of this procedure.

[0271] Also, the first condition determination may be executed based on the identification information included in the registration request message, and / or the subscriber information, and / or the operator policy. For example, the first condition determination may be true if the network permits the request of UE_A10. Also, the first condition determination may be false if the network does not permit the request of UE_A10. Furthermore, the first condition determination may be true if the network where UE_A10 is to be registered and / or the devices in the network support the function requested by UE_A10, and may be false if they do not support it. Furthermore, the first condition determination may be true if the network determines that it is in a congested state, and may be false if it determines that it is not in a congested state. Note that the conditions for determining the true or false of the first condition determination may not be limited to the conditions described above.

[0272] Also, the fourth condition determination may be executed based on whether AMF_A240 has received an SM, or may be executed based on whether an SM message is included in the registration request message. For example, the fourth condition determination may be true when AMF_A240 has received an SM and / or when an SM message is included in the registration request message, and may be false when AMF_A240 has not received an SM and / or when an SM message is not included in the registration request message. Note that the conditions for determining the truth or falsehood of the fourth condition determination may not be limited to the conditions described above.

[0273] [1.3.2. Overview of the PDU session establishment procedure] Next, an overview of the PDU session establishment procedure performed to establish a PDU session for DN_A5 will be described. Hereinafter, the PDU session establishment procedure is also referred to as this procedure. This procedure is a procedure for each device to establish a PDU session. Note that each device may execute this procedure in a state where the registration procedure has been completed, or may execute it during the registration procedure. Also, each device may start this procedure in the registered state, or may start this procedure at any timing after the registration procedure. Further, each device may establish a PDU session based on the completion of the PDU session establishment procedure. Furthermore, each device may establish a plurality of PDU sessions by executing this procedure a plurality of times.

[0274] [1.3.2.1. Example of the PDU session establishment procedure] An example of the procedure for executing the PDU session establishment procedure will be described with reference to FIG. 11. Hereinafter, each step of this procedure will be described. First, UE_A10 starts the PDU session establishment procedure by transmitting a PDU Session Establishment Request message to core network_B via access network_B (S1100). In other words, the UE transmits a PDU session establishment request message to SMF_A230 within core network_B190 to start the PDU session establishment procedure.

[0275] Specifically, UE_A10 uses the N1 interface to send a PDU session establishment request message to AMF_A240 in core network_B190 via NR node_A122 (S1100). AMF_A receives the PDU session establishment request message and performs a third condition check. The third condition check is for AMF_A to determine whether to accept the request of UE_A10. In the third condition check, AMF_A determines whether the fifth condition check is true or false. If the third condition check is true, core network_B starts processing #1 in the core network (S1101); if the third condition check is false, it starts the procedure of (B) in this procedure. The steps when the third condition check is false will be described later. Here, processing #1 in the core network may be the selection of SMF_A by AMF_A in core network_B190 and / or the transmission and reception of the PDU session establishment request message between AMF_A and SMF_A.

[0276] Core network_B190 starts processing #1 in the core network. In processing #1 in the core network, AMF_A240 may select SMF_A230 as the NF of the routing destination of the PDU session establishment request message and send or transfer the PDU session establishment request message to the selected SMF_A230 using the N11 interface. Here, AMF_A240 may select the routing destination SMF_A230 based on the information contained in the PDU session establishment request message. More specifically, AMF_A240 may select the routing destination SMF_A230 based on each identification information obtained based on the reception of the PDU session establishment request message, and / or subscriber information, and / or network capability information, and / or operator policy, and / or network status, and / or the context already held by AMF_A240.

[0277] Furthermore, the PDU session establishment request message may be a NAS message. Also, the PDU session establishment request message may be, but is not limited to, a message that requests the establishment of a PDU session.

[0278] Here, UE_A10 may include one or more pieces of identification information out of the first to fourth pieces of identification information in the PDU session establishment request message, and by including these pieces of identification information, UE_A10 may indicate its request. Note that two or more pieces of these identification information may be configured as one or more pieces of identification information.

[0279] Furthermore, UE_A10 may request the establishment of a PDU session belonging to a network slice, indicate the network slice to which the PDU session requested by UE_A10 belongs, or indicate the network slice to which the PDU session is planned to belong in the future, by including the first piece of identification information, and / or the second piece of identification information, and / or the third piece of identification information, and / or the fourth piece of identification information in the PDU session establishment request message and transmitting it.

[0280] More specifically, UE_A10 may request the establishment of a PDU session belonging to a network slice, indicate the network slice to which the PDU session requested by UE_A10 belongs, or indicate the network slice to which the PDU session is planned to belong in the future, in the PDU session established for the DN identified by the second piece of identification information, by associating and transmitting the first piece of identification information and the second piece of identification information.

[0281] Furthermore, UE_A10 may make a combined request by combining two or more pieces of identification information out of the first to fourth pieces of identification information. Note that the matters indicated by UE_A10 by transmitting each piece of identification information may not be limited to these.

[0282] Further, UE_A10 may determine which of the first to fourth identification information to include in the PDU session establishment request message based on the UE_A10's capability information, and / or policies such as UE policies, and / or the UE_A10's preferences, and / or applications (upper layers). Note that the determination by UE_A10 of which identification information to include in the PDU session establishment request message is not limited to this.

[0283] SMF_A230 in core network_B190 receives the PDU session establishment request message and performs a third condition check. The third condition check is for SMF_A230 to determine whether to accept the request of UE_A10. In the third condition check, SMF_A230 determines whether the third condition check is true or false. If the third condition check is true, SMF_A230 starts the procedure (A) in this procedure; if the third condition check is false, SMF_A230 starts the procedure (B) in this procedure. Note that the steps when the third condition check is false will be described later.

[0284] Hereinafter, the steps when the third condition check is true, that is, each step of the procedure (A) in this procedure, will be described. SMF_A230 selects the UPF_A235 to which the PDU session is to be established and performs an eleventh condition check.

[0285] Here, the 11th condition determination is for determining whether each device executes Process #2 in the core network. Here, Process #2 in the core network may include the start and / or execution of the PDU session establishment authentication procedure by each device, and / or the transmission and reception of a Session Establishment request message between SMF_A and UPF_A in Core Network_B190, and / or the transmission and reception of a Session Establishment response message, etc. (S1103). In the 11th condition determination, SMF_A230 determines whether the 11th condition determination is true or false. When the 11th condition determination is true, SMF_A230 starts the PDU session establishment authentication approval procedure, and when the 11th condition determination is false, it omits the PDU session establishment authentication approval procedure. Note that the details of the PDU session establishment authentication approval procedure for Process #2 in the core network will be described later.

[0286] Next, based on the 11th condition determination and / or the completion of the PDU session establishment authentication approval procedure, SMF_A230 sends a session establishment request message to the selected UPF_A235 and starts Procedure (A) in this procedure. Note that SMF_A230 may start Procedure (B) in this procedure without starting Procedure (A) in this procedure based on the completion of the PDU session establishment authentication approval procedure.

[0287] Here, based on each identification information, and / or network capability information, and / or subscriber information, and / or operator policy, and / or network status, and / or context that SMF_A230 already holds, which is obtained based on the reception of the PDU session establishment request message, SMF_A230 may select one or more UPF_A235. Note that when multiple UPF_A235 are selected, SMF_A230 may send a session establishment request message to each UPF_A235.

[0288] UPF_A235 receives a session establishment request message and creates a context for the PDU session. Further, UPF_A235 transmits a session establishment response message to SMF_A230 based on receiving the session establishment request message and / or creating the context for the PDU session. Further, SMF_A230 receives the session establishment response message. Note that the session establishment request message and the session establishment response message may be control messages transmitted and received on the N4 interface. Further, the session establishment response message may be a response message to the session establishment request message.

[0289] Further, SMF_A230 may perform address allocation of the address to be assigned to UE_A10 based on receiving the PDU session establishment request message and / or selecting UPF_A235 and / or receiving the session establishment response message. Note that SMF_A230 may perform address allocation of the address to be assigned to UE_A10 during the PDU session establishment procedure, or may perform it after the completion of the PDU session establishment procedure.

[0290] Specifically, when SMF_A230 assigns an IPv4 address without using DHCPv4, it may perform address allocation during the PDU session establishment procedure and may also transmit the assigned address to UE_A10. Further, when SMF_A230 assigns an IPv4 address and / or an IPv6 address and / or an IPv6 prefix using DHCPv4 or DHCPv6 or SLAAC (Stateless Address Autoconfiguration), it may perform address allocation after the PDU session establishment procedure and may also transmit the assigned address to UE_A10. Note that the address allocation performed by SMF_A230 is not limited to these.

[0291] Furthermore, SMF_A230 may send the assigned address to UE_A10 included in the PDU session establishment acceptance message based on the completion of the address assignment for the address assigned to UE_A10, or may send it to UE_A10 after the completion of the PDU session establishment procedure.

[0292] Based on the reception of the PDU session establishment request message, and / or the selection of UPF_A235, and / or the reception of the session establishment response message, and / or the completion of the address assignment for the address assigned to UE_A10, SMF_A230 sends a PDU session establishment accept message to UE_A10 via AMF_A240 (S1110).

[0293] Specifically, SMF_A230 sends a PDU session establishment acceptance message to AMF_A240 using the N11 interface, and AMF_A240 that has received the PDU session establishment acceptance message sends the PDU session establishment acceptance message to UE_A10 using the N1 interface.

[0294] Furthermore, SMF_A230 may include the PDU session ID, and / or DNN, and / or S-NSSAI in the PDU session establishment acceptance message.

[0295] Here, the PDU session ID included in the PDU session establishment acceptance message may be the same as the PDU session ID included in the PDU session establishment request message, or may be a different PDU session ID. Furthermore, the PDU session ID included in the PDU session establishment acceptance message may be a PDU session ID selected by the network.

[0296] Furthermore, the DNN included in the PDU session establishment acceptance message may be the same as the DNN included in the PDU session establishment request message, or may be a different DNN. Furthermore, the DNN included in the PDU session establishment acceptance message may be a DNN selected by the network, or may be a default DNN.

[0297] Furthermore, the S-NSSAI included in the PDU session establishment acceptance message may be the same as the S-NSSAI included in the PDU session establishment request message, or may be a different S-NSSAI. Furthermore, the S-NSSAI included in the PDU session establishment acceptance message may be an S-NSSAI selected by the network, or may be a default S-NSSAI.

[0298] Furthermore, SMF_A230 may also include a mapped S-NSSAI in the PDU session establishment acceptance message. In other words, SMF_A230 may include a mapped S-NSSAI together with the S-NSSAI in the PDU session establishment acceptance message. Here, the mapped S-NSSAI may be the mapped S-NSSAI of the S-NSSAI included in the PDU session establishment acceptance message. Specifically, the mapped S-NSSAI may be the S-NSSAI of the home PLMN associated with the S-NSSAI included in the PDU session establishment acceptance message. In other words, the S-NSSAI and the mapped S-NSSAI included in the PDU session establishment acceptance message may be associated, or the mapped S-NSSAI and the S-NSSAI of the home PLMN may be associated.

[0299] Also, when the PDU session is a PDN connection, the PDU session establishment acceptance message may be a PDN connectivity accept message. Further, the PDU session establishment acceptance message may be an NAS message transmitted and received on the N11 interface and the N1 interface. Also, the PDU session establishment acceptance message is not limited thereto, and any message indicating that the establishment of the PDU session has been accepted may be used.

[0300] UE_A10 receives a PDU session establishment acceptance message from SMF_A230. By receiving the PDU session establishment acceptance message, UE_A10 recognizes the content of various identification information included in the PDU session establishment acceptance message.

[0301] Next, based on the completion of the reception of the PDU session establishment acceptance message, UE_A10 transmits a PDU session establishment complete message to SMF_A230 via AMF_A240 (S1114). Further, SMF_A230 receives the PDU session establishment complete message and performs a second condition determination.

[0302] Specifically, UE_A10 transmits a PDU session establishment complete message to AMF_A240 using the N1 interface, and AMF_A240 that has received the PDU session establishment complete message transmits the PDU session establishment complete message to SMF_A230 using the N11 interface.

[0303] Also, when the PDU session is a PDN connection, the PDU session establishment complete message may be a PDN connectivity complete message or an activate default EPS bearer context accept message. Further, the PDU session establishment complete message may be a NAS message transmitted and received on the N1 interface and the N11 interface. Also, the PDU session establishment complete message may be a response message to the PDU session establishment accept message, and is not limited thereto, as long as it is a message indicating that the PDU session establishment procedure is completed.

[0304] The second condition determination is for the SMF_A230 to determine the type of message on the N4 interface to be transmitted and received. If the second condition determination is true, processing #3 within the core network may be started (S1115). Here, processing #3 within the core network may include transmission and reception of a session modification request message and / or transmission and reception of a session modification response message, etc. The SMF_A230 transmits a session modification request message to the UPF_A235, and further receives a session modification acceptance message transmitted by the UPF_A235 that has received the session modification request message. Also, if the second condition determination is false, the SMF_A230 executes processing #2 within the core network. That is, the SMF_A transmits a session establishment request message to the UPF_A235, and further receives a session modification acceptance message transmitted by the UPF_A235 that has received the session establishment request message.

[0305] Each device completes the procedure of (A) during this procedure based on the transmission and reception of a PDU session establishment completion message, and / or the transmission and reception of a session change response message, and / or the transmission and reception of a session establishment response message, and / or the transmission and reception of an RA (Router Advertisement).

[0306] Next, the steps when the third condition determination is false, that is, each step of the procedure of (B) during this procedure will be described. SMF_A230 transmits a PDU session establishment reject message to UE_A10 via AMF_A240 (S1122) and starts the procedure of (B) during this procedure.

[0307] Specifically, SMF_A230 transmits a PDU session establishment reject message to AMF_A240 using the N11 interface, and AMF_A240 that has received the PDU session establishment request message transmits a PDU session establishment reject message to UE_A10 using the N1 interface.

[0308] In addition, when the PDU session is a PDN connection, the PDU session establishment reject message may be a PDN connectivity reject message. Furthermore, the PDU session establishment reject message may be a NAS message transmitted and received on the N11 interface and the N1 interface. Also, the PDU session establishment reject message is not limited to this, and any message indicating that the establishment of the PDU session has been rejected may be used.

[0309] Here, SMF_A230 may include one or more pieces of identification information among the 11th to 18th identification information in the PDU session establishment reject message, and by including these pieces of identification information, it may indicate that the request of UE_A10 has been rejected. Note that two or more pieces of this identification information may be configured as one or more pieces of identification information.

[0310] Furthermore, by including the 11th identification information, and / or the 12th identification information, and / or the 13th identification information, and / or the 14th identification information, and / or the 15th identification information, and / or the 16th identification information, and / or the 17th identification information, and / or the 18th identification information in the PDU session establishment rejection message and transmitting it, SMF_A230 may indicate that the request to establish a PDU session belonging to a network slice has been rejected, or may indicate a network slice to which the PDU session is not permitted to belong.

[0311] More specifically, by associating and transmitting the 18th identification information with the 12th identification information, in the PDU session established for the DN identified by the 12th identification information, SMF_A230 may indicate that the request to establish a PDU session belonging to a network slice has been rejected, or may indicate a network slice to which the PDU session is not permitted to belong.

[0312] Furthermore, by including the 18th identification information in the PDU session establishment rejection message and transmitting it, in the registration area and / or the tracking area to which UE_A10 currently belongs, SMF_A230 may indicate that the request to establish a PDU session belonging to a network slice has been rejected, or may indicate a network slice to which the PDU session is not permitted to belong.

[0313] Furthermore, by including the 18th identification information in the PDU session establishment rejection message and transmitting it, in the access network to which UE_A10 is currently connected, SMF_A230 may indicate that the request to establish a PDU session belonging to a network slice has been rejected, or may indicate a network slice to which the PDU session is not permitted to belong.

[0314] Furthermore, SMF_A230 may indicate the value of the first timer by including the 11th identification information and / or the 14th identification information in the PDU session establishment rejection message, or may indicate whether the same procedure as this procedure should be performed again after the completion of this procedure.

[0315] Furthermore, SMF_A230 may make a combined request by combining two or more pieces of identification information among the 11th to 18th identification information. Note that the matters indicated by SMF_A230 by transmitting each piece of identification information may not be limited to these.

[0316] Note that SMF_A230 may determine which of the 11th to 18th identification information to include in the PDU session establishment rejection message based on the received identification information, and / or the network capability information, and / or policies such as operator policies, and / or the network state.

[0317] Furthermore, the 12th identification information may be information indicating the same DNN as the DNN indicated by the 2nd identification information. Furthermore, the 13th identification information may be information indicating the same PDU session ID as the PDU session ID indicated by the 3rd identification information. Furthermore, the 18th identification information may be information transmitted when the 1st identification information is received and / or when the network slice indicated by the 1st identification information is not permitted by the network. Note that the determination by SMF_A230 as to which identification information to include in the PDU session establishment rejection message is not limited to this.

[0318] As described above, the core network_B190 notifies the congestion management applied to UE_A10 by transmitting a PDU session establishment rejection message. Note that, thereby, the core network_B190 may indicate applying congestion management to UE_A10, and / or executing congestion management on UE_A10, and / or information identifying the type of congestion management to be applied, and / or information identifying the object of congestion management such as the DNN and / or S-NSSAI corresponding to the applied congestion management, and / or the value of the timer associated with the applied congestion management.

[0319] Here, each of the above-described pieces of information may be information identified by one or more pieces of identification information from the 11th identification information to the 18th identification information.

[0320] The PDU session establishment rejection message received by UE_A10 from SMF_A230 may include one or more pieces of identification information among the 11th identification information to the 18th identification information.

[0321] Next, UE_A10 performs the fourth process (S1124) based on the reception of the PDU session establishment rejection message. Also, UE_A10 may perform the fourth process based on the completion of this procedure.

[0322] Hereinafter, a first example of the fourth process will be described.

[0323] Here, the fourth process may be a process in which UE_A10 recognizes the matter indicated by SMF_A230. Further, the fourth process may be a process in which UE_A10 stores the received identification information as a context, or a process in which UE_A10 transfers the received identification information to an upper layer and / or a lower layer. Further, the fourth process may be a process in which UE_A10 recognizes that the request of this procedure has been rejected.

[0324] Furthermore, when UE_A10 receives the 14th identification information and the 11th identification information, the 4th process may be a process in which UE_A10 sets the value indicated by the 14th identification information as the first timer value, or may be a process of starting the first timer with the set timer value. Furthermore, when UE_A10 receives the 11th identification information, the 4th process may be a process of executing one or more of the behaviors from the 1st to the 11th behaviors.

[0325] Furthermore, when UE_A10 receives the 18th identification information and the 11th identification information, the 4th process may be a process in which UE_A10 executes the 12th behavior based on the information for identifying the NW slice included in the 18th identification information and the network slice association rule included in the 18th identification information or the network slice association rule that UE_A10 has previously held and set.

[0326] Furthermore, when UE_A10 receives a plurality of the 14th identification information and the 11th identification information, the 4th process may be a process in which UE_A10 executes the 13th behavior based on the plurality of first timers included in each 14th identification information and the priority management rule of the backoff timer held by UE_A10.

[0327] Furthermore, when UE_A10 receives a plurality of the 14th identification information and the 11th identification information, the 4th process may be a process in which UE_A10 executes the 14th behavior based on the plurality of first timers included in each 14th identification information.

[0328] Here, the 12th to 15th behaviors may be congestion management mainly executed by UE_A10 based on the rules and / or policies inside UE_A10. Specifically, for example, UE_A10 may include in its internal storage unit and / or control unit a policy (UE policy), and / or rules, a management function for the policy and / or rules, a policy enforcer for operating UE_A10 based on the policy and / or rules, one or more applications, and a session management instance (session manager) for managing one or more PDU sessions established or attempted to be established based on requests from each application. By executing any of the 12th to 15th behaviors as the fourth process based on these, congestion management mainly dominated by UE_A10 may be realized. Here, the policy and / or rules may include any one or more of network slice association rules, and / or priority management rules for backoff timers, and / or NSSP (Network Slice Selection Policy). Furthermore, these may be pre-set in UE_A10 or received from the network. Also, here, the policy enforcer may be an NSSP enforcer. Also, here, the application may be an application layer protocol, and may attempt to establish or establish a PDU session based on requests from the application layer protocol. Also, here, the session management instance may be a software element dynamically generated per PDU session. Also, here, as internal processing of UE_A10, S-NSSAI may be grouped, or processing based on the grouping of S-NSSAI may be executed. Note that the internal configuration and processing of UE_A10 are not limited to these, and each element may be realized by software or executed as software processing inside UE_A10.

[0329] Furthermore, UE_A10 may switch to EPS in the fourth process or based on the completion of the fourth process, and may start location registration in EPS based on the DCN ID included in the 18th identification information. Note that the switching of UE_A10 to EPS may be based on a handover procedure or may be a RAT switching led by UE_A10. Also, when UE_A10 receives the 18th identification information including the DCN ID, it may execute the switching to EPS during or after the fourth process.

[0330] Furthermore, the fourth process may be a process in which UE_A10 starts this procedure again after a certain period, or may be a process in which UE_A10 transitions to a state where its requests are limited or restricted.

[0331] Note that UE_A10 may transition to the first state upon completion of the fourth process.

[0332] Next, a second example of the fourth process will be described.

[0333] Here, the fourth process may be a process in which UE_A10 recognizes the matters indicated by SMF_A230. Furthermore, the fourth process may be a process in which UE_A10 stores the received identification information as a context, or may be a process in which UE_A10 transfers the received identification information to the upper layer and / or the lower layer.

[0334] Furthermore, in the fourth process, a process of identifying to apply congestion management based on one or more pieces of identification information among the 11th to 18th identification information may be executed.

[0335] Furthermore, in the fourth process, based on one or more pieces of identification information among the 11th to 18th identification information, a process of identifying which type of congestion management among the first to fourth congestion managements to apply, and a process of identifying the DNN and / or S-NSSAI associated with the congestion management to be applied may be executed. More specifically, this process may be the process described in the 15th behavior.

[0336] Furthermore, in the fourth process, based on one or more pieces of identification information from the 11th identification information to the 18th identification information, the value to be set for the first timer corresponding to the congestion management to be applied is identified and set, and the counting of the first timer may be started. More specifically, this process may be the process described in the eighth behavior.

[0337] Furthermore, in the fourth process, one or more of the first behavior to the seventh behavior may be executed in accordance with the start or completion of any of the processes described above.

[0338] Furthermore, in the fourth process, one or more of the ninth behavior to the 15th behavior may be executed in accordance with the start or completion of any of the processes described above.

[0339] Note that UE_A10 may transition to the first state upon completion of the fourth process.

[0340] So far, the content of the fourth process has been described using the first example and the second example, but it may not be limited to these processes of the fourth process. For example, the fourth process may be a process that combines a part of the plurality of detailed processes described in the first example and a part of the plurality of detailed processes described in the second example.

[0341] Furthermore, UE_A10 may recognize that the request of UE_A10 has been rejected by receiving a PDU session establishment rejection message or by not receiving a PDU session establishment acceptance message. Each device completes the procedure (B) in this procedure based on the transmission and reception of the PDU session establishment rejection message.

[0342] Each device completes this procedure based on the completion of procedure (A) or (B) during this procedure. In addition, each device may transition to a state where the PDU session is established based on the completion of procedure (A) during this procedure, or may recognize that this procedure has been rejected based on the completion of procedure (B) during this procedure, or may transition to a state where the PDU session is not established, or may transition to the first state.

[0343] Furthermore, each device may perform processing based on the identification information transmitted and received in this procedure based on the completion of this procedure. In other words, UE_A10 may perform the fourth processing based on the completion of this procedure, or may transition to the first state after the completion of the fourth processing.

[0344] Also, the third condition determination may be executed based on the identification information included in the PDU session establishment request message, and / or the subscriber information, and / or the operator policy. For example, the third condition determination may be true if the network permits the request of UE_A10. Also, the third condition determination may be false if the network does not permit the request of UE_A10. Furthermore, the third condition determination may be true if the network of the connection destination of UE_A10 and / or the device in the network supports the function requested by UE_A10, and may be false if it does not support it. Furthermore, the third condition determination may be true if the network determines that it is in a congested state, and may be false if it determines that it is not in a congested state. Note that the conditions for determining the true or false of the third condition determination are not limited to the conditions described above.

[0345] Also, the second condition determination may be executed based on whether or not a session on the N4 interface for the PDU session is established. For example, the second condition determination may be true if the session on the N4 interface for the PDU session is established, and may be false if it is not established. Note that the conditions for determining the true or false of the second condition determination are not limited to the conditions described above.

[0346] Also, the 11th condition determination may be executed based on the identification information included in the PDU session establishment request message, and / or the subscriber information, and / or the operator policy. For example, the 11th condition determination may be true if the network permits the implementation of authentication and / or authorization by DN_A5 during this procedure. Also, the 11th condition determination may be false if the network does not permit the implementation of authentication and / or authorization by DN_A5 during this procedure. Furthermore, the 11th condition determination may be true if the network of the connection destination of UE_A10 and / or the device in the network supports the implementation of authentication and / or authorization by DN_A5 during this procedure, and may be false if not. Furthermore, the 11th condition determination may be true if the 61st identification information is received, and may be false if not received. In other words, the 11th condition determination may be true if information such as an SM PDU DN Request Container and / or a container including a plurality of information is received, and may be false if not received. Note that the conditions for determining the truth or falsehood of the 11th condition determination may not be limited to the above-mentioned conditions.

[0347] Through the transmission and reception of the PDU session establishment rejection message in the above procedure, the core network_B190 notifies UE_A10 of the congestion management to be applied, and UE_A10 can apply the congestion management instructed by the core network_B190. Note that the core network B190 and UE_A10 may apply a plurality of congestion managements by executing the procedures and processes described in this procedure a plurality of times. Note that each applied congestion management may be a congestion management with differences in different types of congestion management, and / or congestion management corresponding to different DNNs, and / or congestion management corresponding to different S-NNSAIs, and / or congestion management with differences in the combination of DNN and S-NSSAI.

[0348] [1.3.3. Overview of Network-Driven Session Management Procedure] Next, an overview of the network-led session management procedure will be described. Hereinafter, the network-led session management procedure is also referred to as this procedure. This procedure is a procedure for session management that the network executes in a leading manner for an established PDU session. Note that this procedure may be executed at any timing after the aforementioned registration procedure and / or PDU session establishment procedure are completed and each device has transitioned to the first state. Also, each device may transmit and receive a message including identification information for stopping or changing congestion management during this procedure, or may start behavior based on new congestion management instructed by the network based on the completion of this procedure.

[0349] Furthermore, UE_A10 may stop the application of congestion management identified based on the control information transmitted and received by this procedure. In other words, the core network_B190 can notify UE_A10 to stop the application of congestion management identifiable using these control information by leading this procedure and further transmitting the control message and control information of this procedure to UE_A10.

[0350] Note that this procedure may be, for example, a network-led PDU session change (PDU session modification) procedure and / or a network-led PDU session release (PDU session release) procedure, or may execute a network-led session management procedure not limited to these. Note that each device may transmit and receive a PDU session change message in the network-led PDU session change procedure, or may transmit and receive a PDU session release message in the network-led PDU session release procedure.

[0351] [1.3.3.1. Example of the First Network-Led Session Management Procedure] An example of the network-led session management procedure will be described with reference to FIG. 12. In this chapter, this procedure refers to the network-led session management procedure. Hereinafter, each step of this procedure will be described.

[0352] As described above, based on the completion of the registration procedure and / or the PDU session establishment procedure, UE_A10 and each device in core network_B190 that have transitioned to the first state (S1200) start a network-initiated session management procedure at any timing. Here, the device in core network_B190 that starts this procedure may be SMF_A and / or AMF_A, and UE_A may transmit and receive messages in this procedure via AMF_A and / or access network_B.

[0353] Specifically, a device in core network_B190 transmits a network-initiated session management request message to UE_A (S1202). Here, the device in core network_B190 may include the 21st identification information in the network-initiated session management request message, or by including this identification information, it may indicate the request of core network_B190. Furthermore, the device in core network_B190 may include the PDU session ID in the network-initiated session management request message, or by including the PDU session ID, it may request to perform a change to the PDU session identified by the PDU session ID.

[0354] Note that the PDU session ID included in the PDU session change request message may be the PDU session ID of the established PDU session. Furthermore, when this procedure is executed based on a UE-initiated session management procedure, the PDU session ID included in the PDU session change request message may be the same as the PDU session ID included in the PDU session change request message or the PDU session release request message.

[0355] Next, UE_A that has received the network-initiated session management request message transmits a network-initiated session management completion message (S1204). Further, UE_A may execute a fifth process (S1206) based on the 21st identification information received from core network_B190, and may complete this procedure. Also, UE_A10 may perform a fifth process based on the completion of this procedure.

[0356] Here, UE_A10 may include the PDU session ID in the network-initiated session management completion message. Note that the PDU session ID included in the network-initiated session management completion message may be the same as the PDU session ID included in the network-initiated session management request message.

[0357] An example of the fifth process will be described below.

[0358] Here, the fifth process may be a process in which UE_A10 recognizes the matter indicated by core network_B190, or may be a process in which UE_A10 recognizes the request of core network_B190. Further, the fifth process may be a process in which UE_A10 stores the received identification information as a context, or may be a process in which UE_A10 transfers the received identification information to an upper layer and / or a lower layer.

[0359] Also, the message transmitted and received in the network-initiated session management request may be a PDU session modification command (PDU SESSION MODIFICATION COMMAND), or may be a PDU session release command (PDU SESSION RELEASE COMMAND), and is not limited thereto.

[0360] Note that UE_A10 may perform congestion management identification processing applied by UE_A10 based on the received 21st identification information in the fifth process. Here, the congestion management identification processing may be the 17th behavior.

[0361] Furthermore, when the UE_A10 receives the 21st identification information, the fifth process may be the 16th behavior. Specifically, for example, it may be a process of stopping one or more timers being executed based on the aforementioned fourth process.

[0362] In other words, the UE_A10 that has received the 21st identification information identifies the congestion management for stopping or changing instructed by the network by executing the 17th behavior, and then implements the stop or change of the identified congestion management by executing the 16th behavior.

[0363] Furthermore, each device may perform a process based on the identification information transmitted and received in this procedure based on the completion of this procedure. In other words, the UE_A10 may perform the fifth process based on the completion of this procedure, or may complete this procedure after the completion of the fifth process.

[0364] In the above procedure, by transmitting and receiving a network-initiated session management request message, the core network_B190 can instruct the UE_A10 to stop or change the congestion management that the UE_A10 is already applying. Furthermore, the UE_A10 can implement the stop or change of the congestion management that the UE_A10 is applying based on the network-initiated session management request message. Here, when the UE_A10 is applying one or more congestion managements, it may identify the congestion management to be stopped or changed based on the reception of the identification information included in the network-initiated session management request message from the core network_B190. Note that each applied congestion management may be a congestion management that differs in different types of congestion management, and / or congestion management corresponding to different DNNs, and / or congestion management corresponding to different S-NNSAIs, and / or congestion management that differs in the combination of DNN and S-NSSAI.

[0365] Furthermore, each device completes a first network-initiated session management procedure based on the completion of the above-described processing and / or the transmission and reception of a network-initiated session management request message and / or a network-initiated session management completion message.

[0366] Furthermore, based on the completion of the first network-initiated session management procedure, UE_A10 may perform UE processing related to the execution of a backoff timer described below. In other words, UE_A10 may perform UE processing related to the execution of a backoff timer based on the transmission and reception of a network-initiated session management request message and / or a network-initiated session management completion message.

[0367] [1.3.3.2. Example of the second network-initiated session management procedure] In the example of the first network-initiated session management procedure described in Section 1.3.3.1, an example of stopping congestion management during the procedure was described regardless of which congestion management among the first to fourth congestion managements was applied to UE_A10.

[0368] Not limited thereto, the procedure described in the example of the first network-initiated session management procedure described in Section 1.3.3.1 may be a procedure executed according to congestion management. For example, it may be a procedure executed for congestion management classified into the first congestion management, the third congestion management, and the fourth congestion management among one or more congestion managements applied by UE_A10.

[0369] In other words, UE_A10 may stop the congestion management corresponding to the first congestion management, the third congestion management, and the fourth congestion management by the fifth process.

[0370] While the count of the backoff timer associated with the second convergence management is in progress, if UE_10 receives a network-initiated session management request message for the second convergence management, UE_A10 may respond to core network_B190 without stopping the backoff timer associated with the second convergence management.

[0371] In other words, while the count of the backoff timer associated with S-NSSAI#A is in progress, if UE_A10 receives a network-initiated session management request message for the converged S-NSSAI#A and any DNN, UE_A10 may respond to core network_B190 without stopping the backoff timer associated with S-NSSAI#A.

[0372] Thus, for the second convergence management, upon receiving a network-initiated session management request message, UE_A10 shall send a response message to the network-initiated session management request message to core network_B190, but may continue the convergence management. Therefore, the suppression of the transmission of UE-initiated session management request messages regulated by the second convergence management may continue.

[0373] Here, as described above, the network-initiated session management request message in this procedure may be a PDU session modification command (PDU SESSION MODIFICATION COMMAND) message in a network-initiated PDU session modification procedure, or may be a PDU session release command (PDU SESSION RELEASE COMMAND) message in a network-initiated PDU session release procedure.

[0374] Furthermore, as described above, the network-initiated session management request message in this procedure may include a PDU session ID. Furthermore, the PDU session ID may be the same as the PDU session ID described in the first network-initiated session management procedure described in Section 1.3.3.1.

[0375] Furthermore, as described above, the network-initiated session management completion message in response to the PDU session change command message in this procedure may be a PDU session change completion message (PDU SESSION MODIFICATION COMPLETE), and the network-initiated session management completion message in response to the PDU session release command message may be a PDU session release completion message (PDU SESSION RELEASE COMPLETE). Also, when the network-initiated session management request message is a PDU session change command and / or a PDU session release message, UE_A10 and core network_B190 may be configured to perform further detailed processing described below in addition to the above-described processing.

[0376] Furthermore, as described above, the network-initiated session management completion message in this procedure may include a PDU session ID. Furthermore, the PDU session ID may be the same as the PDU session ID described in the first network-initiated session management procedure described in Section 1.3.3.1.

[0377] For example, when the core network_B190 transmits a network-initiated session management request message including information indicating a Reactivation Required, the following processing may be executed. Note that the information indicating a Reactivation Required is information indicating a request for activation, and as a specific example, it may be 5G Session Management Cause #39.

[0378] The following describes a first processing and a procedure example when information indicating a reactivation request is received.

[0379] When UE_A10 receives a network-initiated session management request message including information indicating a Reactivation Required, instead of immediately initiating a UE-initiated PDU session establishment procedure after the completion of the network-initiated session management procedure, it waits for the congestion management to be released and then initiates the UE-initiated PDU session establishment procedure again. Here, this UE-initiated PDU session establishment procedure may be the UE-initiated PDU session establishment procedure for the PDU session type, SSC mode, DNN, and S-NSSAI provided when establishing the PDU session to be changed or released.

[0380] Note that waiting for the congestion management to be released may be executed after the timer associated with the second congestion management expires. In other words, it may be executed after the count of the timer associated with the second congestion management is completed and / or after the timer value associated with the second congestion management becomes zero.

[0381] Furthermore, UE_A10 may include the following supplementary information in the network-initiated session management completion message.

[0382] The supplementary information may be information indicating waiting for the expiration of a timer and / or information indicating the remaining timer value. Here, the timer may be a timer associated with the second congestion management. Also, waiting for the expiration of the timer may mean executing after the expiration (Expire) of the timer. In other words, it may be executed after the completion of the count of the timer associated with the second congestion management and / or after the timer value associated with the second congestion management becomes zero.

[0383] Note that the core network B_190 may receive a network-initiated session management completion message including supplementary information and recognize the value of the remaining timer. Further, it may recognize that a UE-initiated PDU session establishment procedure is initiated after the time indicated by the remaining timer has elapsed.

[0384] Here, the remaining timer recognized by the core network_B190 may be the value indicated by the received supplementary information, or may be a value obtained by considering the offset between the transmission time of UE_A10 in the network-initiated session management completion message and the reception time of the core network_B190 with respect to the value indicated by the received supplementary information.

[0385] Also, not limited to the first processing and procedure example when receiving information indicating a reactivation request, the second processing and procedure example when receiving information indicating a reactivation request may be executed as follows.

[0386] As described above, for the second convergence management, when receiving a network-initiated session management request message, UE_A10 shall send a response message to the network-initiated session management request message to core network_B190, but may continue the convergence management. Therefore, although the suppression state of the transmission of UE-initiated session management request messages regulated by the second convergence management continues, UE_A10 and / or core network_B190 may be set to be allowed as long as they initiate the UE-initiated PDU session establishment procedure again.

[0387] In other words, when UE_A10 receives a network-initiated session management request message containing information indicating a reactivation required, it shall initiate the UE-initiated PDU session establishment procedure again after the completion of the network-initiated network-initiated session management procedure. Here, this UE-initiated PDU session establishment procedure may be the UE-initiated PDU session establishment procedure provided at the time of establishing the PDU session to be changed or released, for the PDU session type, SSC mode, DNN, and S-NSSAI.

[0388] Note that while the application of the convergence management continues, UE_A10 and core network B190 may execute and complete the procedures allowed as this exception, but UE_A10 may suppress the initiation of other UE-initiated session management procedures suppressed by the second convergence management.

[0389] In addition to the first and second processing and procedure examples when receiving information indicating a reactivation required, the following third processing and procedure example when receiving information indicating a reactivation required may be executed.

[0390] As described above, for the second convergence management, when receiving a network-initiated session management request message, UE_A10 sends a response message to the core network_B190 for the network-initiated session management request message. Further, when UE_A10 receives a network-initiated session management request message that includes information indicating a Reactivation Required, UE_A10 may stop applying the second convergence management.

[0391] In other words, when the network-initiated session management request message does not include information indicating a Reactivation Required, UE_A10 may continue the convergence management. In this case, the suppression of the transmission of the UE-initiated session management request message regulated by the second convergence management may continue.

[0392] Therefore, when UE_A10 receives a network-initiated session management request message that includes information indicating a Reactivation Required, UE_A10 resumes leading the UE-initiated PDU session establishment procedure after the completion of the network-initiated network-initiated session management procedure. Here, this UE-initiated PDU session establishment procedure may be the UE-initiated PDU session establishment procedure provided at the time of establishing the PDU session to be changed or released, for the PDU session type, SSC mode, DNN, and S-NSSAI.

[0393] Also, not limited to the first, second, and third processing and procedure examples when receiving information indicating a reactivation request, as follows, the information indicating a reactivation request may be set not to be transmitted by the core network_B190.

[0394] More specifically, when the core network_B190 sends a network-initiated session management request message to the UE_A10 to which convergence management is applied, it may be configured to suppress including information indicating a reactivation requirement.

[0395] Alternatively, when the core network_B190 sends a network-initiated session management request message to the UE_A10 to which the second convergence management is applied, it may be configured to suppress including information indicating a reactivation requirement.

[0396] As described above, the processing and procedures of the UE_A10 and the core network B190 have been described. However, the processing of the core network_B190 described in this chapter may be, more specifically, processing executed by a control device such as the SMF_A230 and / or the AMF_A240, which are devices within the core network_B190. Therefore, when the core network B190 transmits and receives control messages, it may be that control devices such as the SMF_A230 and / or the AMF_A240, which are devices within the core network_B190, transmit and receive control messages.

[0397] Furthermore, not limited to this chapter, to cancel the application of or stop the convergence management may include the process of stopping the backoff timer associated with the convergence management, and to continue the application of or continue the convergence management may include continuing the count of the backoff timer associated with the convergence management.

[0398] Also, in the first, second, and third processing and procedure examples when receiving the information indicating the reactivation requirement described in this chapter, the network-initiated session management request message and / or the network-initiated session management procedure have been described as being for the UE_A10 with respect to the converged S-NSSAI#A and any DNN.

[0399] In other words, this congested S-NSSAI#A and any DNN may be associated with the network-led session management request message in this chapter and / or the S-NSSAI#A and any DNN associated with the PDU session targeted by the network-led session management procedure.

[0400] Note that UE_A10 and core network_B190 may execute the anchor relocation procedure in SSC mode 2 that includes the procedures in this chapter, and continue communication by switching to the anchor of the PDU session or a different PDU session of the anchor. Here, the anchor relocation procedure in SSC mode 2 is a procedure initiated by core network_B190, and the procedure associated with the transmission of the PDU session release command executed within this procedure may be any of the procedures described in this chapter.

[0401] Also, UE_A10 and core network_B190 may execute the anchor relocation procedure in SSC mode 3 that includes the procedures in this chapter, and continue communication by switching to the anchor of the PDU session or a different PDU session of the anchor. Here, the anchor relocation procedure in SSC mode 3 is a procedure initiated by core network_B190, and the procedure associated with the transmission of the PDU session change command executed within this procedure may be any of the procedures described in this chapter.

[0402] Next, the processing when the UE moves with a change in PLMN in a state where congestion management is applied will be described.

[0403] Here, the processing when UE_A10 changes the PLMN, particularly in a state where the first congestion management is applied, will be described. Here, the first congestion management and the processing regulated when the first congestion management is applied may be as already described.

[0404] When repeated, the first congestion management may be DNN-based congestion management. For example, the first congestion management may be that when the NW receives a UE-initiated session management request using DNN#A from UE_A10, and congestion for a specific DNN, e.g., DNN#A, is detected in the NW, the NW applies to UE_A10 a congestion management based on a message that rejects the UE-initiated session management request. In this case, in the application of the first congestion management, UE_A10 may start counting a backoff timer corresponding to the first congestion management received from the NW, and may be set not to send a UE-initiated session management request using DNN#A until the backoff timer expires. Note that using a DNN may mean including DNN information in a UE-initiated session management request such as a PDU session establishment request message.

[0405] Here, for the sake of explanation, such first congestion management is expressed as "the first congestion management for a specific DNN".

[0406] Also, in the first congestion management, even when DNN information is not included in a UE-initiated session management request, the NW may select a default DNN in an NW-initiated manner and make it a congestion management target. In other words, the first congestion management may be that when the NW receives a UE-initiated session management request not using DNN information from UE_A10, and congestion for the default DNN is detected in the NW, the NW applies to UE_A10 a congestion management based on a message that rejects the UE-initiated session management request. In this case, in the application of the first congestion management, UE_A10 may start counting a backoff timer corresponding to the first congestion management received from the NW, and may be set not to send a UE-initiated session management request not using a DNN until the backoff timer expires. Note that not using a DNN may mean not including DNN information in a UE-initiated session management request such as a PDU session establishment request message.

[0407] Here, for the sake of explanation, since the first convergence management for such default DNNs is applied based on UE-initiated session management requests that do not use DNN information, in order to distinguish it from the first convergence management for a specific DNN, it is expressed as "Convergence Management for No DNN". Furthermore, UE-initiated session management requests such as PDU session establishment request messages that do not use DNN are expressed as UE-initiated session management requests using No DNN. For example, a PDU session establishment request message using No DNN is a PDU session establishment request message that does not use DNN.

[0408] When UE_A10 is counting the backoff timer associated with the first convergence management for a specific DNN during PLMN change, or when the backoff timer associated with the first convergence management for a specific DNN is deactivated, UE_A10 may be set to be able to send a PDU session establishment request message using this specific DNN in the new PLMN. Therefore, based on this setting, UE_10 may send a PDU session establishment request message using this specific DNN.

[0409] Here, UE_A10 may not stop the backoff timer that was being counted and continue counting until the timer expires. Alternatively, UE_A10 may continue to hold the deactivated backoff timer in the deactivated state.

[0410] In this way, the first convergence management for a specific DNN may be associated with a PLMN.

[0411] For example, when the first congestion management for a specific DNN is applied, the UE starts counting a backoff timer associated with the PLMN and the specific DNN, and if the backoff timer is zero or not deactivated, the UE does not perform PDU session establishment using the specific DNN associated with the backoff timer in the PLMN associated with the backoff timer. Also, when the backoff timer is deactivated, the UE does not perform PDU session establishment using the specific DNN associated with the backoff timer in the PLMN associated with the backoff timer until the terminal power is turned off or the USIM is removed. Also, when the backoff timer is zero, the UE may perform PDU session establishment using the specific DNN associated with the backoff timer in the PLMN associated with the backoff timer.

[0412] In other words, if UE_A10 is counting the backoff timer associated with the first congestion management for a specific DNN and the previous PLMN during a PLMN change, or if the backoff timer associated with the first congestion management for a specific DNN and the previous PLMN is deactivated, and further, if UE_A10 is not counting the backoff timer associated with the first congestion management for the specific DNN and the new PLMN, and if the backoff timer associated with the first congestion management for the specific DNN and the new PLMN is not deactivated, then UE_A10 may be configured to be able to send a PDU session establishment request message using this specific DNN in the new PLMN. Further, based on this configuration, UE_10 may send a PDU session establishment request message using this specific DNN.

[0413] When UE_A10 is counting the backoff timer associated with the first congestion management for No DNN during PLMN change, or when the backoff timer associated with the first congestion management for No DNN is deactivated, UE_A10 may be configured to be able to send a PDU session establishment request message without using a DNN in the new PLMN. Therefore, based on this configuration, UE_10 may also send a PDU session establishment request message using this specific DNN.

[0414] Here, UE_A10 may continue counting without stopping the backoff timer that was being counted until the timer expires. Alternatively, UE_A10 may continue to hold the deactivated backoff timer in the deactivated state.

[0415] In this way, the first congestion management for No DNN may be associated with the PLMN. In other words, when UE_A10 is counting the backoff timer of the first congestion management for No DNN associated with the previous PLMN during PLMN change, or when the backoff timer of the first congestion management for No DNN associated with the previous PLMN is deactivated, and furthermore, when the backoff timer of the first congestion management for No DNN associated with the new PLMN is not being counted and the backoff timer of the first congestion management for No DNN associated with the PLMN is not deactivated, UE_A10 may be configured to be able to send a PDU session establishment request message without using a DNN in the new PLMN. Furthermore, based on this configuration, UE_10 may also send a PDU session establishment request message without using a DNN.

[0416] As described above, UE_A10 may perform similar processing regardless of whether the first congestion management is for a specific DNN or for No DNN.

[0417] That is, when UE_A10 is counting the backoff timer of the first congestion management associated with the PLMN before the change, or when the backoff timer of the first congestion management associated with the PLMN before the change is deactivated, and further, when UE_A10 is not counting the backoff timer of the first congestion management associated with the PLMN after the change and the backoff timer of the first congestion management associated with the PLMN after the change is not deactivated, UE_A10 may be configured to be able to send, in the new PLMN, a PDU session establishment request message using a specific DNN that was restricted by the congestion management associated with the PLMN before the change, and / or a PDU session establishment request message without using a DNN.

[0418] Alternatively, UE_A10 may perform different processes depending on whether the first congestion management is for a specific DNN or for No DNN.

[0419] When UE_A10 is counting the backoff timer associated with the first congestion management for a specific DNN during a PLMN change, or when the backoff timer associated with the first congestion management for a specific DNN is deactivated, UE_A10 may be configured not to send a PDU session establishment request message using this specific DNN in the new PLMN. Therefore, based on this configuration, UE_10 may be restricted from sending a PDU session establishment request message using this specific DNN.

[0420] Here, UE_A10 may continue counting the backoff timer without stopping it until the timer expires. Alternatively, UE_A10 may continue to hold the deactivated backoff timer in the deactivated state.

[0421] Thus, the first congestion management for a specific DNN may be applied even in different PLMNs.

[0422] On the other hand, when UE_A10 is counting the backoff timer associated with the first congestion management for No DNN during the PLMN change, or when the backoff timer associated with the first congestion management for No DNN is deactivated, UE_A10 may be configured to be able to send a PDU session establishment request message without using a DNN in the new PLMN. Therefore, based on this configuration, UE_10 may also send a PDU session establishment request message using this specific DNN.

[0423] Here, UE_A10 may continue counting without stopping the counted backoff timer until the timer expires. Alternatively, UE_A10 may continue to hold the deactivated backoff timer in the deactivated state.

[0424] Thus, the first congestion management for No DNN may be associated with a PLMN.

[0425] For example, when the first congestion management for No DNN is applied, the UE starts counting the backoff timer associated with the PLMN and No DNN, and if the backoff timer is not zero or deactivated, the UE does not perform a PDU session establishment using the No DNN associated with the backoff timer in the PLMN associated with the backoff timer. Also, when the backoff timer is deactivated, the UE does not perform a PDU session establishment using the No DNN associated with the backoff timer in the PLMN associated with the backoff timer until the terminal power is turned off or the USIM is removed. Also, when the backoff timer is zero, the UE may perform a PDU session establishment using the No DNN associated with the backoff timer in the PLMN associated with the backoff timer.

[0426] In other words, when UE_A10 is counting the backoff timer for the first congestion management for No DNN associated with the PLMN before the change in the PLMN change, or when the backoff timer for the first congestion management for No DNN associated with the PLMN before the change is deactivated, and further, when UE_A10 is not counting the backoff timer for the first congestion management for No DNN associated with the PLMN after the change and the backoff timer for the first congestion management for No DNN associated with the PLMN is not deactivated, UE_A10 may be set to be able to send a PDU session establishment request message without using a DNN in the new PLMN. Further, based on this setting, UE_10 may send a PDU session establishment request message without using a DNN.

[0427] Here, as the processing associated with the above-described PLMN change, whether the same processing or different processing is performed regardless of whether the first congestion management is for a specific DNN or for No DNN may be set based on the information pre-set in UE_A10, or may be determined by whether the second PLMN after the change is an equivalent PLMN with respect to the first PLMN before the change. For example, when the second PLMN after the change is not an equivalent PLMN with respect to the first PLMN before the change, the same processing may be applied. Also, when the second PLMN after the change is an equivalent PLMN with respect to the first PLMN before the change, different processing may be executed.

[0428] Furthermore, UE_A10 may determine its behavior based not only on whether the PLMN is an equivalent PLMN, but also on further detailed conditions. For example, when the second PLMN after the change is an equivalent PLMN to the first PLMN before the change and the registration area is not changed in the PLMN change, and when the second PLMN after the change is an equivalent PLMN to the first PLMN before the change and the registration area is changed in the PLMN change, UE_A10 may be set to perform different behaviors.

[0429] Note that the behavior of UE_A10 executed in each case may be one of the behaviors during PLMN change described so far.

[0430] For example, a first example in the case where the second PLMN after the change is an equivalent PLMN to the first PLMN before the change and the registration area is not changed in the PLMN change will be described. In such a PLMN change, if UE_A10 is counting a backoff timer associated with the first congestion management for a specific DNN, or if the backoff timer associated with the first congestion management for a specific DNN is deactivated, UE_A10 may be set not to send a PDU session establishment request message using this specific DNN in the new PLMN. Therefore, based on this setting, UE_10 may be restricted from sending a PDU session establishment request message using this specific DNN.

[0431] Next, a second example is described where the second PLMN after the change is an equivalent PLMN with respect to the first PLMN before the change, and the registration area is not changed in the PLMN change. When UE_A10 is counting the backoff timer associated with the first congestion management for No DNN in such a PLMN change, or when the backoff timer associated with the first congestion management for No DNN is deactivated, UE_A10 may be set not to send a PDU session establishment request message without using a DNN in the new PLMN. Therefore, based on this setting, UE_10 may be restricted from sending a PDU session establishment request message without using a DNN.

[0432] Next, a first example is described where the second PLMN after the change is an equivalent PLMN with respect to the first PLMN before the change, and the registration area changes in the PLMN change. When UE_A10 is counting the backoff timer of the first congestion management for No DNN associated with the PLMN before the change, or when the backoff timer of the first congestion management for No DNN associated with the PLMN before the change is deactivated, and further, when the backoff timer of the first congestion management for No DNN associated with the PLMN after the change is not being counted and the backoff timer of the first congestion management for No DNN associated with the PLMN is not deactivated, UE_A10 may be set to be able to send a PDU session establishment request message without using a DNN in the new PLMN. Furthermore, based on this setting, UE_10 may send a PDU session establishment request message without using a DNN.

[0433] Next, a second example is described in which the changed second PLMN is an equivalent PLMN with respect to the first PLMN before the change, and the registration area changes in this PLMN change. When UE_A10 is counting the backoff timer for the first congestion management for a specific DNN associated with the PLMN before the change, or when the backoff timer for the first congestion management for a specific DNN associated with the PLMN before the change is deactivated, in such a PLMN change, and furthermore, when UE_A10 is not counting the backoff timer for the first congestion management for a specific DNN associated with the changed PLMN, and the backoff timer for the first congestion management for a specific DNN associated with the PLMN is not deactivated, UE_A10 may be set to be able to send a PDU session establishment request message using the specific DNN in the new PLMN. Furthermore, based on this setting, UE_10 may also send a PDU session establishment request message using the specific DNN.

[0434] Next, a third example is described in which the changed second PLMN is an equivalent PLMN with respect to the first PLMN before the change, and the registration area changes in this PLMN change. In such a PLMN change, UE_A10 may stop the backoff timer associated with the first congestion management for a specific DNN and / or No DNN. Thereby, UE_A10 may be set to be able to send a PDU session establishment request message using the specific DNN and / or a PDU session establishment request message without using the specific DNN in the new PLMN. Furthermore, based on this setting, UE_10 may also send a PDU session establishment request message using the specific DNN and / or a PDU session establishment request message without using the specific DNN.

[0435] Also, whether the same processing or different processing is performed regardless of whether the first convergence management is for a specific DNN or for no DNN may be set based on the information pre-set in UE_A10, but as previously described, it may also be determined by whether the changed second PLMN is an equivalent PLMN to the previous first PLMN. Regardless of the first convergence management, different processing may be set to be executed for the second to fourth convergence managements. For example, when the changed second PLMN is not an equivalent PLMN to the previous first PLMN, the same processing may be applied. Also, when the changed second PLMN is an equivalent PLMN to the previous first PLMN, different processing may be executed.

[0436] Furthermore, UE_A10 may determine its behavior based not only on whether it is an equivalent PLMN but also on further detailed conditions. For example, UE_A10 may be set to execute different behaviors depending on whether the changed second PLMN is an equivalent PLMN to the previous first PLMN and the registration area is not changed in that PLMN change, and whether the changed second PLMN is an equivalent PLMN to the previous first PLMN and the registration area is changed in that PLMN change.

[0437] Note that the behavior of UE_A10 executed in each case may be one of the behaviors at the time of PLMN change described so far.

[0438] Hereinafter, an example when the second convergence management is applied will be described.

[0439] For example, a first example will be described where the second PLMN after the change is an equivalent PLMN with respect to the first PLMN before the change, and the registration area is not changed in this PLMN change. When the UE_A10 is counting the backoff timer associated with the second congestion management for a specific S-NSSAI in such a PLMN change, or when the backoff timer associated with the second congestion management for a specific S-NSSAI is deactivated, the UE_A10 may be set not to transmit a PDU session establishment request message using this specific S-NSSAI in the new PLMN. Therefore, based on this setting, the UE_10 may be restricted from transmitting a PDU session establishment request message using this specific S-NSSAI.

[0440] Also, a second example will be described where the second PLMN after the change is an equivalent PLMN with respect to the first PLMN before the change, and the registration area is not changed in this PLMN change. When the UE_A10 is counting the backoff timer associated with the second congestion management for No S-NSSAI in such a PLMN change, or when the backoff timer associated with the first congestion management for No S-NSSAI is deactivated, the UE_A10 may be set not to transmit a PDU session establishment request message without using an S-NSSAI in the new PLMN. Therefore, based on this setting, the UE_10 may be restricted from transmitting a PDU session establishment request message without using an S-NSSAI.

[0441] Next, a first example will be described in which the changed second PLMN is the equivalent PLMN with respect to the first PLMN before the change, and there is a change in the registration area in this PLMN change. In such a PLMN change, if UE_A10 is counting the backoff timer for the second congestion management for No S-NSSAI associated with the PLMN before the change, or if the backoff timer for the second congestion management for No S-NSSAI associated with the PLMN before the change is deactivated, and furthermore, if UE_A10 is not counting the backoff timer for the second congestion management for No S-NSSAI associated with the PLMN after the change and the backoff timer for the second congestion management for No S-NSSAI associated with the PLMN is not deactivated, then UE_A10 may be configured to be able to send a PDU session establishment request message without using the S-NSSAI in the new PLMN. Further, based on this configuration, UE_10 may send a PDU session establishment request message without using the S-NSSAI.

[0442] Next, a second example is described in which the second PLMN after the change is an equivalent PLMN to the first PLMN before the change, and the registration area changes in this PLMN change. When the UE_A10 is counting the backoff timer for the second congestion management for a specific S-NSSAI associated with the PLMN before the change, or when the backoff timer for the second congestion management for a specific S-NSSAI associated with the PLMN before the change is deactivated, in such a PLMN change, and further, when the UE_A10 is not counting the backoff timer for the second congestion management for a specific S-NSSAI associated with the PLMN after the change, and the backoff timer for the second congestion management for a specific S-NSSAI associated with the PLMN is not deactivated, the UE_A10 may be set to be able to send a PDU session establishment request message using the specific S-NSSAI in the new PLMN. Further, based on this setting, the UE_10 may also send a PDU session establishment request message using the specific S-NSSAI.

[0443] Next, a third example is described in which the second PLMN after the change is an equivalent PLMN to the first PLMN before the change, and the registration area changes in this PLMN change. In such a PLMN change, the UE_A10 may stop the backoff timer associated with the second congestion management for a specific S-NSSAI and / or No S-NSSAI. Thereby, the UE_A10 may be set to be able to send a PDU session establishment request message using the specific S-NSSAI and / or a PDU session establishment request message not using the specific S-NSSAI in the new PLMN. Further, based on this setting, the UE_10 may also send a PDU session establishment request message using the specific S-NSSAI and / or a PDU session establishment request message not using the specific S-NSSAI.

[0444] Hereinafter, an example when the third congestion management is applied is described.

[0445] For example, a first example will be described where the second PLMN after the change is an equivalent PLMN to the first PLMN before the change and the registration area is not changed in the PLMN change. When the UE_A10 is counting the backoff timer associated with the third congestion management for a specific [S-NSSAI, DNN] in such a PLMN change, or when the backoff timer associated with the third congestion management for a specific [S-NSSAI, DNN] is deactivated, the UE_A10 may be set not to transmit a PDU session establishment request message using this specific [S-NSSAI, DNN] in the new PLMN. Therefore, based on this setting, the UE_10 may be restricted from transmitting a PDU session establishment request message using this specific [S-NSSAI, DNN].

[0446] Also, a second example will be described where the second PLMN after the change is an equivalent PLMN to the first PLMN before the change and the registration area is not changed in the PLMN change. When the UE_A10 is counting the backoff timer associated with the third congestion management for [No S-NSSAI, DNN] in such a PLMN change, or when the backoff timer associated with the third congestion management for [No S-NSSAI, DNN] is deactivated, the UE_A10 may be set not to transmit a PDU session establishment request message for [No S-NSSAI, DNN] in the new PLMN. Therefore, based on this setting, the UE_10 may be restricted from transmitting a PDU session establishment request message for [No S-NSSAI, DNN].

[0447] Next, a first example will be described in which the second PLMN after the change is the equivalent PLMN for the first PLMN before the change and the registration area changes in this PLMN change. In such a PLMN change, if UE_A10 is counting the backoff timer for the third congestion management for [No S-NSSAI, DNN] associated with the PLMN before the change, or if the backoff timer for the third congestion management for [No S-NSSAI, DNN] associated with the PLMN before the change is deactivated, and further, if UE_A10 is not counting the backoff timer for the third congestion management for [No S-NSSAI, DNN] associated with the PLMN after the change and the backoff timer for the third congestion management for [No S-NSSAI, DNN] associated with the PLMN is not deactivated, then UE_A10 may be configured to be able to send a PDU session establishment request message for [No S-NSSAI, DNN] in the new PLMN. Further, based on this configuration, UE_10 may also send a PDU session establishment request message for [No S-NSSAI, DNN].

[0448] Next, a second example will be described in the case where the changed second PLMN is an equivalent PLMN with respect to the first PLMN before the change, and the change of the registration area is involved in the PLMN change. When the UE_A10 is counting the back-off timer of the third congestion management for a specific [S-NSSAI, DNN] associated with the PLMN before the change in such a PLMN change, or when the back-off timer of the third congestion management for a specific [S-NSSAI, DNN] associated with the PLMN before the change is deactivated, and further, when the UE_A10 is not counting the back-off timer of the third congestion management for a specific [S-NSSAI, DNN] associated with the PLMN after the change and the back-off timer of the third congestion management for a specific [S-NSSAI, DNN] associated with the PLMN is not deactivated, the UE_A10 may be set to be able to send a PDU session establishment request message using a specific [S-NSSAI, DNN] in the new PLMN. Further, based on this setting, the UE_10 may also send a PDU session establishment request message using a specific [S-NSSAI, DNN].

[0449] Next, a third example will be described in the case where the changed second PLMN is the equivalent PLMN for the first PLMN before the change and the change of the registration area is involved in the PLMN change. In such a PLMN change, UE_A10 may stop the backoff timer associated with the third congestion management for a specific [S-NSSAI, DNN] and / or [No S-NSSAI, DNN]. Thereby, UE_A10 may be configured to be able to send a PDU session establishment request message using a specific [S-NSSAI, DNN] and / or a PDU session establishment request message for [No S-NSSAI, DNN] in the new PLMN. Furthermore, based on this configuration, UE_10 may send a PDU session establishment request message using a specific [S-NSSAI, DNN] and / or a PDU session establishment request message for [No S-NSSAI, DNN].

[0450] Note that the deactivation of the backoff timer may mean that the backoff timer and / or the congestion management associated with the backoff timer has transitioned to a deactivated state. Note that UE_A10 may deactivate the backoff timer and / or the congestion management associated with the backoff timer when receiving a timer value indicating deactivation.

[0451] Here, the backoff timer to be deactivated and / or the congestion management associated with the backoff timer may be associated with the congestion management types from 1 to 4. Which congestion management type the backoff timer to be deactivated and / or the congestion management associated with the backoff timer is associated with may be similarly determined and recognized when receiving the backoff timer value.

[0452] More specifically, UE_A10 may receive, from the NW, the 14th identification information indicating activation of a backoff timer and / or congestion management associated with the backoff timer, and the 15th identification information, and may activate the backoff timer for the type of congestion management indicated by the 15th identification information.

[0453] Also, in a state where the backoff timer and / or congestion management is activated, the application of congestion management may continue until the power of the terminal is turned off or the USIM is removed. Further, the processes restricted at that time may be the same as the processes restricted when the count of the backoff timer is in progress according to the type of each congestion management.

[0454] Furthermore, each device completes a second network-initiated session management procedure based on the completion of the above-described processes and / or the transmission and reception of network-initiated session management request messages and / or network-initiated session management completion messages.

[0455] UE_A10 may perform UE processing related to the execution of a backoff timer described later based on the completion of the second network-initiated session management procedure. In other words, UE_A10 may perform UE processing related to the execution of a backoff timer described later based on the transmission and reception of network-initiated session management request messages and / or network-initiated session management completion messages.

[0456] [1.4. Overview of UE-Initiated Session Management Procedure] Next, an overview of the UE-initiated session management procedure will be described. Hereinafter, the UE-initiated session management procedure is also referred to as this procedure. This procedure is a procedure for session management that the UE initiates and executes for an established PDU session. Note that this procedure may be executed at any timing after the aforementioned registration procedure and / or PDU session establishment procedure is completed and each device has transitioned to the first state. Also, each device may transmit and receive a message including identification information for stopping or changing congestion management during this procedure, or may start behavior based on new congestion management instructed by the network based on the completion of this procedure.

[0457] Furthermore, UE_A10 may stop the application of congestion management identified based on the control information transmitted and received by this procedure. In other words, the core network_B190 can notify UE_A10 to stop the application of congestion management identifiable using these control information by leading this procedure and further transmitting the control message and control information of this procedure to UE_A10.

[0458] Furthermore, UE_A10 may start the application of congestion management identified based on the control information transmitted and received by this procedure. In other words, the core network_B190 can notify UE_A10 to start the application of congestion management identifiable using these control information by leading this procedure and further transmitting the control message and control information of this procedure to UE_A10.

[0459] Furthermore, this procedure may be, but is not limited to, a UE-initiated PDU session modification procedure and / or a UE-initiated PDU session release procedure, etc., and may execute UE-initiated session management procedures. In addition, in the UE-initiated PDU session modification procedure, each device may transmit and receive a PDU session modification request message, and / or a PDU session modification command message, and / or a PDU session modification completion message, and / or a PDU session modification rejection message. In the UE-initiated PDU session release procedure, each device may transmit and receive a PDU session release request message, and / or a PDU session release command message, and / or a PDU session release completion message, and / or a PDU session release rejection message.

[0460] Furthermore, each device completes the UE-initiated session management procedure based on the completion of the above-described processing and / or the transmission and reception of a UE-initiated session management request message and / or a UE-initiated session management completion message.

[0461] Based on the completion of the UE-initiated session management procedure, UE_A10 may perform UE processing related to the execution of a backoff timer described later. In other words, based on the transmission and reception of a UE-initiated session management request message and / or a UE-initiated session management completion message, UE_A10 may perform UE processing related to the execution of a backoff timer described later.

[0462] [1.4.1. Example of UE-initiated PDU session modification procedure] In this chapter, this procedure refers to the UE-initiated PDU session modification procedure. Hereinafter, each step of this procedure will be described with reference to FIG. 13.

[0463] As described above, based on the completion of the registration procedure and / or the PDU session establishment procedure, UE_A10 that has transitioned to the first state (S1300) can initiate a UE-initiated PDU session modification procedure at any timing. In other words, UE_A10 may initiate a UE-initiated PDU session modification procedure for the established PDU session at any timing. Further in other words, UE_A10 may initiate a UE-initiated PDU session modification procedure using the same PDU session ID as the established PDU session at any timing.

[0464] First, UE_A10 initiates a UE-initiated PDU session modification procedure by sending a PDU session modification request message to SMF_A230 (S1302). Here, UE_A10 may include the PDU session ID in the PDU session modification request message, or by including the PDU session ID, may request to perform a modification to the PDU session identified by the PDU session ID.

[0465] Note that the PDU session ID included in the PDU session modification request message may be the PDU session ID of the established PDU session. Further, when a backoff timer associated with the DNN is running, the PDU session ID included in the PDU session modification request message may be a PDU session ID for identifying a PDU session not associated with the DNN. Further, when a backoff timer associated with the S-NSSAI is running, the PDU session ID included in the PDU session modification request message may be a PDU session ID for identifying a PDU session not associated with the S-NSSAI. Further, when a backoff timer associated with both the DNN and the S-NSSAI is running, the PDU session ID included in the PDU session modification request message may be a PDU session ID for identifying a PDU session not associated with both the DNN and the S-NSSAI.

[0466] Next, SMF_A230 receives the PDU session modification request message sent by UE_A10. If SMF_A230 accepts the request of UE_A10, it initiates a network-initiated PDU session modification procedure. Conversely, if SMF_A230 rejects the request of UE_A10, it sends a PDU session modification rejection message to UE_A10. Hereinafter, the case where SMF_A230 rejects the request of UE_A10 will be described.

[0467] Based on the acceptance of the PDU session establishment request message, SMF_A230 sends a PDU session modification rejection message to UE_A10 (S1304). Here, SMF_A230 may include one or more pieces of identification information among the 11th to 18th identification information in the PDU session modification rejection message, or may include the PDU session ID, and by including these pieces of identification information, it may indicate that the request of UE_A10 has been rejected. Note that two or more pieces of these identification information may be configured as one or more pieces of identification information.

[0468] Here, the PDU session ID included in the PDU session modification rejection message may be the same as the PDU session ID included in the PDU session modification request message. In other words, the PDU session ID included in the PDU session modification rejection message may be the same as the PDU session ID provided by UE_A10 during this procedure.

[0469] Furthermore, by sending the PDU session modification rejection message, SMF_A230 may notify the congestion management applied to UE_A10. Furthermore, thereby, core network_B190 may indicate to UE_A10 to apply congestion management and / or execute congestion management, and / or information identifying the type of congestion management to be applied, and / or information identifying the congestion management target such as DNN and / or S-NSSAI associated with the congestion management to be applied, and / or notify the value of the timer associated with the congestion management to be applied.

[0470] Here, each of the above-described pieces of information may be information identified by one or more pieces of identification information from the 11th identification information to the 18th identification information.

[0471] UE_A10 receives a PDU session change rejection message. Further, each device completes this procedure based on the transmission and reception of the PDU session change rejection message and / or the completion of the network-initiated PDU session change procedure.

[0472] Here, UE_A10 may recognize that its request has been rejected based on the reception of the PDU session change rejection message. Further, UE_A10 may perform a fourth process based on the reception of the PDU session change rejection message. Note that the fourth process may be performed based on the completion of this procedure.

[0473] Here, the fourth process may be a process similar to the behavior when UE_A10 receives a PDU session establishment rejection message.

[0474] Further, the fourth process may be a process in which UE_A10 recognizes the matters indicated by SMF_A230. Further, the fourth process may be a process in which UE_A10 stores the received identification information as a context, or a process in which UE_A10 transfers the received identification information to an upper layer and / or a lower layer. Further, the fourth process may be a process in which UE_A10 recognizes that the request of this procedure has been rejected.

[0475] Furthermore, in the fourth process, UE_A10 may recognize the applied congestion management by receiving a PDU session change rejection message. Note that UE_A10 may thereby recognize applying and / or executing congestion management, and / or information for identifying the type of congestion management to be applied, and / or information for identifying the target of the applied congestion management such as DNN and / or S-NSSAI, and / or may store and recognize the value of the timer associated with the applied congestion management.

[0476] Furthermore, when UE_A10 receives the eleventh identification information, and / or the fourteenth identification information, and / or the fifteenth identification information, it may set the value indicated by the fourteenth identification information as the value of the backoff timer, or may start the backoff timer with the set timer value. In other words, based on the reception of a PDU session change rejection message including the eleventh identification information, and / or the fourteenth identification information, and / or the fifteenth identification information, UE_A10 may set the value indicated by the fourteenth identification information as the value of the backoff timer, or may start the backoff timer with the set timer value.

[0477] Here, the backoff timer may be a backoff timer associated with the second congestion management, or may be a backoff timer associated with the third congestion management.

[0478] Through the transmission and reception of the PDU session change rejection message in the above procedure, the core network_B190 notifies UE_A10 of the congestion management to be applied, and UE_A10 can apply the congestion management instructed by the core network_B190. Note that the core network B190 and UE_A10 may apply multiple congestion managements by executing the procedures and processes described in this procedure multiple times. Each applied congestion management may be a congestion management with differences in different types of congestion management, and / or congestion management corresponding to different DNNs, and / or congestion management corresponding to different S-NSSAIs, and / or congestion management with differences in the combination of DNN and S-NSSAI.

[0479] Furthermore, each device completes the UE-initiated PDU session change procedure based on the completion of the above-described processing and / or the transmission and reception of a UE-initiated PDU session change rejection message.

[0480] UE_A10 may perform UE processing regarding the execution of a backoff timer described later based on the completion of the UE-initiated PDU session change procedure. In other words, UE_A10 may perform UE processing regarding the execution of a backoff timer described later based on the reception of a PDU session change rejection message.

[0481] [1.4.2. Example of UE-initiated PDU session release procedure] In this chapter, this procedure refers to the UE-initiated PDU session release procedure. Each step of this procedure will be described below.

[0482] The UE-initiated PDU session release procedure may be the same as the above-described PDU session change procedure.

[0483] Specifically, when this procedure is a UE-initiated PDU session release procedure, the above-described PDU session change request message may be read as a PDU session release request message. Furthermore, when this procedure is a UE-initiated PDU session release procedure, the above-described PDU session change behavior message may be read as a PDU session release behavior message.

[0484] Furthermore, when this procedure is a UE-initiated PDU session release procedure, the behavior of SMF_A230 performed based on the reception of a PDU session release request message may be the same as the behavior of SMF_A230 performed based on the reception of the aforementioned PDU session modification request message. Furthermore, when this procedure is a UE-initiated PDU session release procedure, the behavior of UE_A10 performed based on the reception of a PDU session release rejection message may be the same as the behavior of UE_A10 performed based on the reception of the aforementioned PDU session modification rejection message.

[0485] Furthermore, when this procedure is a UE-initiated PDU session release procedure, SMF_A230 may initiate a network-initiated PDU session release procedure based on the reception of a PDU session release request message, or may send a PDU session release rejection message to UE_A10.

[0486] Furthermore, each device completes the UE-initiated PDU session release procedure based on the completion of the above-described processing and / or the transmission and reception of a UE-initiated PDU session release rejection message.

[0487] UE_A10 may perform UE processing related to the execution of a backoff timer described below based on the completion of the UE-initiated PDU session release procedure. In other words, UE_A10 may perform UE processing related to the execution of a backoff timer described below based on the reception of a PDU session release rejection message.

[0488] [1.5. Example of UE Processing Related to Execution of Backoff Timer] In this chapter, the UE's processing related to the execution of the backoff timer will be described. Here, the UE's processing described in this chapter may be performed based on the completion of network-initiated session management procedures and / or UE-initiated session management procedures. In other words, the UE's processing described in this chapter may be performed based on the reception of a PDU session change command message, and / or the reception of a PDU session release command message, and / or the reception of a PDU session change rejection message, and / or the reception of a PDU session release rejection message.

[0489] Furthermore, the processing of UE_A10 and the NW associated with the PLMN change described so far has been described with respect to the first congestion management and / or the backoff timer for the first congestion management. However, similar processing may also be performed for the second congestion management, the third congestion management, and the fourth congestion management. However, the PDU session establishment request message whose transmission is regulated or permitted may be a message corresponding to each type.

[0490] In other words, the congestion management and / or the backoff timer associated with the congestion management may be associated with the PLMN regardless of the type of congestion management.

[0491] Alternatively, the backoff timer associated with any congestion management and / or the congestion management may be set to be associated with the PLMN. Therefore, for the first congestion management, the second congestion management, and the third congestion management, the backoff timer associated with the congestion management and / or the congestion management may be set to be associated with the PLMN. Or, for the first congestion management, the second congestion management, and the third congestion management for No DNN, the backoff timer associated with the congestion management and / or the congestion management may be set to be associated with the PLMN, and the first congestion management for a specific DNN may not be associated with the PLMN.

[0492] In addition, the processing when each congestion management is associated with a PLMN, and / or the processing related to the backoff timer corresponding to each congestion management may be the description of the processing for the first congestion management associated with the PLMN and / or the processing related to the backoff timer corresponding to the first congestion management associated with the PLMN described above, with the first congestion management replaced by each of the second to fourth types of congestion management.

[0493] Also, the processing when each congestion management is not associated with a PLMN, and / or the processing related to the backoff timer corresponding to each congestion management may be the description of the processing for the first congestion management not associated with the PLMN and / or the processing related to the backoff timer corresponding to the first congestion management not associated with the PLMN described above, with the first congestion management replaced by each of the second to fourth types of congestion management.

[0494] However, as described above, the PDU session establishment request message for which transmission is restricted or permitted may be a message corresponding to each type.

[0495] Alternatively, the behavior of counting the backoff timer associated with the second congestion management and / or the third congestion management at the time of PLMN change during execution may be executed as follows in addition to the above-described processing.

[0496] Note that the backoff timer associated with the second congestion management may be, as described so far, a backoff timer for slice-based congestion management. Furthermore, the backoff timer for slice-based congestion management may be a timer that starts and / or stops in units of S-NSSAI and / or PLMN.

[0497] Specifically, the slice-based backoff timer may be a timer associated with a specific S-NSSAI and used to prohibit the transmission of SM request messages using that specific S-NSSAI. In other words, UE_A10 may be configured not to transmit SM request messages using that specific S-NSSAI while this timer is counting.

[0498] Furthermore, while this timer is counting, UE_A10 may be configured such that, based on specific conditions described later, in a new PLMN, the transmission of SM request messages prohibited in the PLMN before the change is allowed. Note that when it is said that the transmission of SM request messages prohibited in the PLMN before the change is allowed, it may mean that the transmission of SM request messages using the same S-NSSAI as the S-NSSAI associated with the backoff timer is allowed.

[0499] Also, it may be a timer associated with no S-NSSAI and used to prohibit the transmission of SM request messages using no S-NSSAI. In other words, UE_A10 may be configured not to transmit SM request messages using no S-NSSAI while this timer is counting. Furthermore, while this timer is counting, UE_A10 may be configured such that, based on specific conditions described later, in a new PLMN, the transmission of SM request messages prohibited in the PLMN before the change is allowed. Note that when it is said that the transmission of SM request messages prohibited in the PLMN before the change is allowed, it may mean that the transmission of SM request messages using no S-NSSAI is allowed.

[0500] Also, as described above, the backoff timer associated with the third congestion management may be a backoff timer for congestion management for a combination of S-NSSAI and DNN. Furthermore, the backoff timer for congestion management for a combination of S-NSSAI and DNN may be a timer that starts and / or stops on a per S-NSSAI, and / or DNN, and / or PLMN basis.

[0501] Specifically, the backoff timer for convergence management for a combination of S-NSSAI and DNN may be a timer associated with a combination of a specific S-NSSA and a specific DNN, and is used to prohibit the transmission of an SM request message using the specific S-NSSAI and the specific DNN. In other words, UE_A10 may be set not to transmit an SM request message using the specific S-NSSAI and the specific DNN during the count of this timer. Further, during the count of this timer, UE_A10 may be set such that, based on specific conditions described later, in a new PLMN, the transmission of an SM request message prohibited in the PLMN before the change is allowed. Note that when it is expressed that the transmission of an SM request message prohibited in the PLMN before the change is allowed, it may mean that the transmission of an SM request message using the same S-NSSAI as the S-NSSAI associated with the backoff timer and the same DNN as the DNN associated with the backoff timer is allowed.

[0502] Also, the backoff timer for convergence management for a combination of S-NSSAI and DNN may be a timer associated with a combination of no S-NSSA and a specific DNN, and is used to prohibit the transmission of an SM request message using no S-NSSAI and the specific DNN. In other words, UE_A10 may be set not to transmit an SM request message including no S-NSSAI and the specific DNN during the count of this timer. Further, during the count of this timer, UE_A10 may be set such that, based on specific conditions described later, in a new PLMN, the transmission of an SM request message prohibited in the PLMN before the change is allowed. Note that when it is expressed that the transmission of an SM request message prohibited in the PLMN before the change is allowed, it may mean that the transmission of an SM request message using no S-NSSAI and the same DNN as the DNN associated with the backoff timer is allowed.

[0503] Also, the backoff timer for convergence management for the combination of S-NSSAI and DNN may be associated with a combination of a specific S-NSSA and no DNN, and may be a timer for prohibiting the transmission of an SM request message using the specific S-NSSAI and no DNN. In other words, UE_A10 may be set not to transmit an SM request message using the specific S-NSSAI and no DNN during the count of this timer. Further, during the count of this timer, UE_A10 may be set such that, based on specific conditions described later, in a new PLMN, the transmission of an SM request message prohibited in the PLMN before the change is allowed. Note that when it is expressed that the transmission of an SM request message prohibited in the PLMN before the change is allowed, it may mean that the transmission of an SM request message using the same S-NSSAI as the S-NSSAI associated with the backoff timer and no DNN is allowed.

[0504] Also, the backoff timer for convergence management for the combination of S-NSSAI and DNN may be associated with a combination of no S-NSSAI and no DNN, and may be a timer for prohibiting the transmission of an SM request message using no S-NSSAI and no DNN. In other words, UE_A10 may be set not to transmit an SM request message using no S-NSSAI and no DNN during the count of this timer. Further, during the count of this timer, UE_A10 may be set such that, based on specific conditions described later, in a new PLMN, the transmission of an SM request message prohibited in the PLMN before the change is allowed. Note that when it is expressed that the transmission of an SM request message prohibited in the PLMN before the change is allowed, it may mean that the transmission of an SM request message using no S-NSSAI and no DNN is allowed.

[0505] In addition, when it is expressed that an SM request message is sent without using an S-NSSAI, it may mean sending the SM request message without including a specific S-NSSAI. When the network receives such an SM request message, since the S-NSSAI is not included, it may recognize that it is a request for a default S-NSSAI and / or a default network slice. Therefore, "no S-NSSAI" may be information indicating that the S-NSSAI is not included in the SM request message and / or information meaning a request for a default network slice.

[0506] Also, when it is expressed that an SM request message is sent without using a DNN, it may mean sending the SM request message without including a specific DNN. When the network receives such an SM request message, since the DNN is not included, it may recognize that it is a request for a default DNN. Therefore, "no DNN" may be information indicating that the S-NSSAI is not included in the SM request message and / or information meaning a request for a default DNN.

[0507] Furthermore, UE_A10 may start a backoff timer associated with the second congestion management based on the reception of the 15th identification information. Furthermore, UE_A10 may set the 14th identification information as the timer value of the backoff timer based on the reception of the 14th identification information. Furthermore, when UE_A10 provides an S-NSSAI in the PDU session establishment procedure, it may associate the S-NSSAI with the backoff timer. Conversely, when UE_A10 does not provide an S-NSSAI in the PDU session establishment procedure, it may associate "no S-NSSAI" with the backoff timer.

[0508] Furthermore, based on the reception of the 14th identification information and / or the 15th identification information, UE_A10 may perform second congestion management using the S-NSSAI provided by UE_A10 to the network and the S-NSSAI provided by the network to UE_A10. In other words, based on the reception of the 14th identification information and / or the 15th identification information, UE_A10 may associate the S-NSSAI provided by UE_A10 to the network and the S-NSSAI provided by the network to UE_A10 with a backoff timer associated with the second congestion management. Further in other words, the backoff timer associated with the second congestion management may be associated with the S-NSSAI provided by UE_A10 to the network and the S-NSSAI provided by the network to UE_A10.

[0509] Here, the 15th identification information may be the 69th 5GSM (Session Management) cause value. Furthermore, the 15th identification information may be a cause value indicating that the resources for a specific slice are insufficient and the requested service cannot be provided.

[0510] Furthermore, if UE_A10 does not provide the S-NSSAI in the PDU session establishment procedure, UE_A10 may associate "no S-NSSAI" with the S-NSSAI associated with the PDU session in the backoff timer. Furthermore, if UE_A10 does not provide the S-NSSAI in the PDU session establishment procedure, UE_A10 may be associated with the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message with "no S-NSSAI" in the backoff timer.

[0511] Furthermore, in the PDU session establishment procedure, if the S-NSSAI is not provided by UE_A10 together with the PDU session establishment request message, the backoff timer may be associated with no S-NSSAI and the S-NSSAI associated with the PDU session. In other words, in the PDU session establishment procedure, if the S-NSSAI is not provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be no S-NSSAI and the S-NSSAI associated with the PDU session. Further in other words, in the PDU session establishment procedure, if the S-NSSAI is not provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the backoff timer with no S-NSSAI and the S-NSSAI associated with the PDU session.

[0512] Furthermore, in the PDU session establishment procedure, if the S-NSSAI is not provided by UE_A10 together with the PDU session establishment request message, the backoff timer may be associated with no S-NSSAI and the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message. In other words, in the PDU session establishment procedure, if the S-NSSAI is not provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be no S-NSSAI and the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message. Further in other words, in the PDU session establishment procedure, if the S-NSSAI is not provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the backoff timer with no S-NSSAI and the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message.

[0513] Furthermore, in the PDU session establishment procedure, when no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, the backoff timer may be associated with the no S-NSSAI and the S-NSSAI associated with the PDU session. In other words, in the PDU session establishment procedure, when no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be the no S-NSSAI and the S-NSSAI associated with the PDU session. Further in other words, in the PDU session establishment procedure, when no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the backoff timer with the no S-NSSAI and the S-NSSAI associated with the PDU session.

[0514] Furthermore, in the PDU session establishment procedure, when no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, the backoff timer may be associated with the no S-NSSAI and the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message. In other words, in the PDU session establishment procedure, when no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be the no S-NSSAI and the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message. Further in other words, in the PDU session establishment procedure, when no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the backoff timer with the no S-NSSAI and the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message.

[0515] Here, the S-NSSAI associated with the PDU session may be the mapped S-NSSAI associated with the PDU session, or may be the mapped S-NSSAI of the S-NSSAI associated with the PDU session. Further, the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message may be the mapped S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message, or may be the mapped S-NSSAI of the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message.

[0516] Furthermore, during the execution of the backoff timer associated with both no S-NSSAI and the S-NSSAI associated with the PDU session, the transmission of the SM request message using no S-NSSAI and / or the transmission of the SM request message using the S-NSSAI associated with the PDU session by UE_A10 may be prohibited. In other words, during the execution of the backoff timer associated with both no S-NSSAI and the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message, the transmission of the SM request message using no S-NSSAI and / or the transmission of the SM request message using the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message by UE_A10 may be prohibited.

[0517] Furthermore, UE_A10 may start a backoff timer associated with the third convergence management based on the reception of the 15th identification information. Furthermore, UE_A10 may set the 14th identification information as the timer value of the backoff timer based on the reception of the 14th identification information. Furthermore, in the PDU session establishment procedure, when UE_A10 provides an S-NSSAI and a DNN, UE_A10 may associate the S-NSSAI and the DNN with the backoff timer. Furthermore, in the PDU session establishment procedure, when UE_A10 provides an S-NSSAI but does not provide a DNN, UE_A10 may associate the S-NSSAI and no DNN with the backoff timer. Furthermore, in the PDU session establishment procedure, when UE_A10 does not provide an S-NSSAI but provides a DNN, UE_A10 may associate no S-NSSAI and the DNN with the backoff timer. Furthermore, in the PDU session establishment procedure, when UE_A10 does not provide an S-NSSAI and a DNN, UE_A10 may associate no S-NSSAI and no DNN with the backoff timer.

[0518] Furthermore, UE_A10 may perform the third convergence management using the S-NSSAI provided by UE_A10 to the network, the S-NSSAI provided by the network to UE_A10, and the DNN based on the reception of the 14th identification information and / or the 15th identification information. In other words, UE_A10 may associate the S-NSSAI provided by UE_A10 to the network, the S-NSSAI provided by the network to UE_A10, and the DNN with the backoff timer associated with the third convergence management based on the reception of the 14th identification information and / or the 15th identification information. Further in other words, the backoff timer associated with the third convergence management may be associated with the S-NSSAI provided by UE_A10 to the network, the S-NSSAI provided by the network to UE_A10, and the DNN. Note that the DNN may be the DNN provided by UE_A10 to the network and / or the DNN provided by the network to UE_A10.

[0519] Here, the 15th identification information may be the 67th 5GSM (Session Management) cause value. Further, the 15th identification information may be a cause value indicating that the requested service cannot be provided due to insufficient resources for a specific slice and DNN.

[0520] Further, in the PDU session establishment procedure, when UE_A10 does not provide the S-NSSAI but provides the DNN, the backoff timer may associate no S-NSSAI, the S-NSSAI associated with the PDU session, and the DNN. Further, in the PDU session establishment procedure, when UE_A10 does not provide the S-NSSAI but provides the DNN, the backoff timer may associate no S-NSSAI, the S-NSSAI included and transmitted in the PDU session establishment acceptance message, and the DNN.

[0521] Further, in the PDU session establishment procedure, when UE_A10 provides no S-NSSAI but provides the DNN together with the PDU session establishment request message, the backoff timer may be associated with no S-NSSAI, the S-NSSAI associated with the PDU session, and the DNN. In other words, in the PDU session establishment procedure, when UE_A10 provides no S-NSSAI but provides the DNN together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be no S-NSSAI and the S-NSSAI associated with the PDU session, and the DNN associated with the backoff timer may be the DNN. Further in other words, in the PDU session establishment procedure, when UE_A10 provides no S-NSSAI but provides the DNN together with the PDU session establishment request message, UE_A10 may associate the backoff timer with no S-NSSAI, the S-NSSAI associated with the PDU session, and the DNN.

[0522] Furthermore, in the PDU session establishment procedure, when the UE_A10 provides no S-NSSAI but provides the DNN together with the PDU session establishment request message, the backoff timer may be associated with the no S-NSSAI, the S-NSSAI included in the PDU session establishment acceptance message and transmitted and received, and the DNN. In other words, in the PDU session establishment procedure, when the UE_A10 provides no S-NSSAI but provides the DNN together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be the no S-NSSAI and the S-NSSAI included in the PDU session establishment acceptance message and transmitted and received, and the DNN associated with the backoff timer may be the DNN. Further in other words, in the PDU session establishment procedure, when the UE_A10 provides no S-NSSAI but provides the DNN together with the PDU session establishment request message, the UE_A10 may associate the backoff timer with the no S-NSSAI, the S-NSSAI included in the PDU session establishment acceptance message and transmitted and received, and the DNN.

[0523] Furthermore, in the PDU session establishment procedure, when a no S-NSSAI and a DNN are provided by UE_A10 together with the PDU session establishment request message, the backoff timer may be associated with the no S-NSSAI, the S-NSSAI associated with the PDU session, and the DNN. In other words, in the PDU session establishment procedure, when a no S-NSSAI and a DNN are provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be the no S-NSSAI and the S-NSSAI associated with the PDU session, and the DNN associated with the backoff timer may be the DNN. Further in other words, in the PDU session establishment procedure, when a no S-NSSAI and a DNN are provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the backoff timer with the no S-NSSAI, the S-NSSAI associated with the PDU session, and the DNN.

[0524] Furthermore, in the PDU session establishment procedure, when a no S-NSSAI and a DNN are provided by UE_A10 together with the PDU session establishment request message, the backoff timer may be associated with the no S-NSSAI, the S-NSSAI included and transmitted / received in the PDU session establishment acceptance message, and the DNN. In other words, in the PDU session establishment procedure, when a no S-NSSAI and a DNN are provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be the no S-NSSAI and the S-NSSAI included and transmitted / received in the PDU session establishment acceptance message, and the DNN associated with the backoff timer may be the DNN. Further in other words, in the PDU session establishment procedure, when a no S-NSSAI and a DNN are provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the backoff timer with the no S-NSSAI, the S-NSSAI included and transmitted / received in the PDU session establishment acceptance message, and the DNN.

[0525] Here, during the execution of the backoff timer associated with the no S-NSSAI, the S-NSSAI associated with the PDU session, and the DNN, the transmission of the SM request message using the no S-NSSAI and the DNN by UE_A10, and / or the transmission of the SM request message using the S-NSSAI associated with the PDU session and the DNN may be prohibited. In other words, during the execution of the backoff timer associated with the no S-NSSAI, the S-NSSAI included and transmitted / received in the PDU session establishment acceptance message, and the DNN included and transmitted / received in the PDU session establishment request message, the transmission of the SM request message using the no S-NSSAI and the DNN by UE_A10, and / or the transmission of the SM request message using the S-NSSAI included and transmitted / received in the PDU session establishment acceptance message and the DNN may be prohibited.

[0526] Furthermore, in the PDU session establishment procedure, if UE_A10 does not provide the S-NSSAI and DNN, the backoff timer may associate no S-NSSAI, the S-NSSAI associated with the PDU session, and no DNN. Furthermore, in the PDU session establishment procedure, if UE_A10 does not provide the S-NSSAI and DNN, the backoff timer may associate no S-NSSAI, the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message, and no DNN.

[0527] Furthermore, in the PDU session establishment procedure, if UE_A10 does not provide the S-NSSAI and DNN together with the PDU session establishment request message, the backoff timer may be associated with no S-NSSAI, the S-NSSAI associated with the PDU session, and no DNN. In other words, in the PDU session establishment procedure, if UE_A10 does not provide the S-NSSAI and DNN together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be no S-NSSAI and the S-NSSAI associated with the PDU session, and the DNN associated with the backoff timer may be no DNN. Further in other words, in the PDU session establishment procedure, if UE_A10 does not provide the S-NSSAI and DNN together with the PDU session establishment request message, UE_A10 may associate the backoff timer with no S-NSSAI, the S-NSSAI associated with the PDU session, and no DNN.

[0528] Furthermore, in the PDU session establishment procedure, when the UE_A10 does not provide the S-NSSAI and the DNN together with the PDU session establishment request message, the backoff timer may be associated with the no S-NSSAI, the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message, and the no DNN. In other words, in the PDU session establishment procedure, when the UE_A10 does not provide the S-NSSAI and the DNN together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be the no S-NSSAI and the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message, and the DNN associated with the backoff timer may be the no DNN. Further in other words, in the PDU session establishment procedure, when the UE_A10 does not provide the S-NSSAI and the DNN together with the PDU session establishment request message, the UE_A10 may associate the backoff timer with the no S-NSSAI, the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message, and the no DNN.

[0529] Furthermore, in the PDU session establishment procedure, when no S-NSSAI and no DNN are provided by UE_A10 together with the PDU session establishment request message, the backoff timer may be associated with no S-NSSAI, the S-NSSAI associated with the PDU session, and no DNN. In other words, in the PDU session establishment procedure, when no S-NSSAI and no DNN are provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be either no S-NSSAI or the S-NSSAI associated with the PDU session, and the DNN associated with the backoff timer may be no DNN. Further in other words, in the PDU session establishment procedure, when no S-NSSAI and no DNN are provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the backoff timer with no S-NSSAI, the S-NSSAI associated with the PDU session, and no DNN.

[0530] Furthermore, in the PDU session establishment procedure, when no S-NSSAI and no DNN are provided by UE_A10 together with the PDU session establishment request message, the backoff timer may be associated with no S-NSSAI, the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message, and no DNN. In other words, in the PDU session establishment procedure, when no S-NSSAI and no DNN are provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the backoff timer may be no S-NSSAI and the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message, and the DNN associated with the backoff timer may be no DNN. Further in other words, in the PDU session establishment procedure, when no S-NSSAI and no DNN are provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the backoff timer with no S-NSSAI, the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message, and no DNN.

[0531] Here, during the execution of the backoff timer associated with no S-NSSAI, the S-NSSAI associated with the PDU session, and no DNN, the transmission of the SM request message using no S-NSSAI and no DNN by UE_A10, and / or the transmission of the SM request message using the S-NSSAI associated with the PDU session and no DNN may be prohibited. In other words, during the execution of the backoff timer associated with no S-NSSAI, the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message, and no DNN, the transmission of the SM request message using no S-NSSAI and no DNN by UE_A10, and / or the transmission of the SM request message using the S-NSSAI included in and transmitted / received in the PDU session establishment acceptance message and no DNN may be prohibited.

[0532] The 14th identification information and / or the 15th identification information may be included in and transmitted / received in a PDU session establishment rejection message that is transmitted / received in the PDU session establishment procedure. Further, the 14th identification information and / or the 15th identification information may be included in and transmitted / received in a PDU session modification rejection message that is transmitted / received in the PDU session modification procedure. Further, the 14th identification information and / or the 15th identification information may be included in and transmitted / received in a PDU session release command message that is transmitted / received in the PDU session release procedure.

[0533] Here, the above-described behavior may be implemented when the S-NSSAI associated with the PDU session is updated. In other words, UE_A10 may implement the above-described behavior when the S-NSSAI associated with the PDU session is updated. Note that the update of the S-NSSAI associated with the PDU session may be implemented based on a change in the PLMN. More specifically, the update of the S-NSSAI associated with the PDU session may be implemented based on a change in the PLMN of UE_A10.

[0534] When executing the count of any one or more of the two examples of the backoff timer for the second congestion management and the four examples of the backoff timer for the third congestion management described above, UE_A10 may be set to execute any one of the first to eighth processing examples shown below.

[0535] First, the first processing example will be described.

[0536] In the first processing example, the 20th identification information may be an information element indicating whether S-NSSAI-based congestion management is applied in the current PLMN and a PLMN other than the PLMN. Note that the S-NSSAI-based congestion management may be the second congestion management or the third congestion management.

[0537] In this case, the 20th identification information may include information indicating that S-NSSAI-based congestion management is applied in the current PLMN and PLMNs other than the said PLMN, or information indicating that S-NSSAI-based congestion management is applied only in the current PLMN. In other words, the 20th identification information may be information including the 21st identification information or the 22nd identification information.

[0538] Here, the 21st identification information may be information indicating that S-NSSAI-based congestion management is applied in the current PLMN and PLMNs other than the said PLMN. Further, the 22nd identification information may be information indicating that S-NSSAI-based congestion management is applied only in the current PLMN.

[0539] Furthermore, the 20th identification information may be an information element indicating whether the counted backoff timer is valid in all PLMNs. Note that the backoff timer may be a backoff timer used in S-NSSAI-based congestion management.

[0540] In this case, the 20th identification information may include information indicating that the counted backoff timer is valid in all PLMNs, or information indicating that the counted backoff timer is valid only in the current PLMN. In other words, the 20th identification information may be information...

Claims

1. A UE (User Equipment), wherein the UE sends a PDU (Protocol Data Unit) session establishment request message to a control device, receives a PDU session establishment acceptance message including a PDU session ID and a first S-NSSAI (Single Network Slice Selection Assistance Information) from the control device, receives a PDU session change rejection message including the PDU session ID and a value of a backoff timer from the control device, a transceiver, and a control unit that starts a backoff timer using the value of the backoff timer based on reception of the PDU session change rejection message, when no S-NSSAI and a DNN (Data Network Name) are provided by the UE together with the PDU session establishment request message, the backoff timer is associated with no S-NSSAI, the first S-NSSAI, and the DNN, during execution of the backoff timer, the transceiver does not send a first SM request message that does not include an S-NSSAI but includes a DNN, does not send a second SM request message that includes the first S-NSSAI and the DNN, when no S-NSSAI and no DNN are provided by the UE together with the PDU session establishment request message, the backoff timer is associated with no S-NSSAI, the first S-NSSAI, and no DNN, during execution of the backoff timer, the transceiver does not send a third SM request message that does not include an S-NSSAI and a DNN, does not send a fourth SM request message that includes the first S-NSSAI and does not include a DNN, characterized by the UE being as described above.

2. The PDU session change rejection message further includes first information and second information, the first information is a reason value indicating that, due to insufficient resources for a specific slice and a DNN, the requested service cannot be provided, the second information is information indicating a value of the backoff timer. The back-off timer is a timer that is started and stopped on a per-S-NSSAI, DNN, and PLMN (Public Land Mobile Network) basis. The UE according to claim 1, characterized in that.

3. The first S-NSSAI is a mapped S-NSSAI. The UE according to claim 1 or claim 2, characterized in that.

4. A communication control method for a UE (User Equipment), comprising: transmitting a PDU (Protocol Data Unit) session establishment request message to a control device; receiving, from the control device, a PDU session establishment acceptance message including a PDU session ID and a first S-NSSAI (Single Network Slice Selection Assistance Information); receiving, from the control device, a PDU session change rejection message including the PDU session ID and a value of a back-off timer; starting a back-off timer using the value of the back-off timer based on receipt of the PDU session change rejection message; When no S-NSSAI and a DNN (Data Network Name) are provided by the UE together with the PDU session establishment request message, the back-off timer is associated with no S-NSSAI, the first S-NSSAI, and the DNN. During execution of the back-off timer, the UE does not transmit a first SM request message that does not include an S-NSSAI but includes a DNN; does not transmit a second SM request message that includes the first S-NSSAI and the DNN; When no S-NSSAI and no DNN are provided by the UE together with the PDU session establishment request message, the back-off timer is associated with no S-NSSAI, the first S-NSSAI, and no DNN. During execution of the back-off timer, the UE does not transmit a third SM request message that does not include an S-NSSAI and a DNN; does not transmit a fourth SM request message that includes the first S-NSSAI but does not include a DNN. A communication control method for a UE, characterized in that.

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