UE and communication control method

Abstract

The present invention provides a communication control method which, when user equipment (UE) receives the reason value of congestion management and the value of a backoff timer while there is the possibility of network slice information correlated to an established PDU session being updated, realizes congestion management in a state in which there is the possibility of the network slice information correlated to the established PDU session being updated, by use of a backoff timer associated with network slice information that the UE transmitted to a device in a core network and network slice information that the UE received from the device in the core network.

Description

[Technical field]

[0001] This application relates to a UE and a communication control method. This application claims the benefit of priority to Japanese Patent Application No. 2019-236464, filed on December 26, 2019, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] 3GPP (3rd Generation Partnership Project), which is engaged in the standardization of recent mobile communication systems, is currently studying SAE (System Architecture Evolution), the system architecture of LTE (Long Term Evolution). 3GPP is defining EPS (Evolved Packet System) specifications as a communication system that will realize an all-IP (Internet Protocol) system. The core network that constitutes EPS is called EPC (Evolved Packet Core).

[0003] In recent years, 3GPP has also been studying next-generation communication technologies and system architectures for 5th Generation (5G) mobile communication systems, and in particular has been working on the specification of 5GS (5G System) as a system for realizing the 5G mobile communication system (see Non-Patent Documents 1 and 2). In 5GS, technical issues for connecting a wide variety of terminals to a cellular network are being extracted and solutions are being specified.

[0004] For example, requirements include optimization and diversification of communication procedures to support continuous mobile communication services in accordance with terminals that support a wide variety of access networks, as well as optimization of system architecture to match the optimization and diversification of communication procedures. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] 3GPP TS 23.501 v16.3.0; 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System Architecture for the 5G System; Stage 2 (Release 16) [Non-Patent Document 2] 3GPP TS 23.502 v16.3.0; 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Procedures for the 5GSystem; Stage 2 (Release 16) [Non-Patent Document 3] 3GPP TS 24.501 v16.3.0; 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Non-Access-Stratum (NAS) protocol for 5G System (5GS);Stage 3 (Release 16) Summary of the Invention [Problem to be solved by the invention]

[0006] In 5GS, in addition to mechanisms for providing functions equivalent to congestion management, control signal management for reasons other than congestion management is also being considered (see Non-Patent Documents 1, 2, and 3).

[0007] In addition, for 5GS, technology is also being considered for updating network slice information associated with an established PDU session when a UE changes PLMN.

[0008] However, it is not clear how to achieve congestion management in a situation where network slice information associated with an established PDU session may be updated.

[0009] The present invention has been made in consideration of these circumstances, and its purpose is to provide a mechanism and a communication control method for achieving congestion management in a situation where network slice information corresponding to a PDU session may be updated. [Means for solving the problem]

[0010] The UE (User Equipment; terminal device) of the present invention includes a transceiver unit that transmits a PDU (Protocol Data Unit) session establishment request message to a control device, receives a PDU session establishment accept 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, first information, and second information from the control device, and a control unit that starts a back-off timer based on reception of the PDU session change rejection message, wherein the first information is a reason value indicating that a requested service cannot be provided due to insufficient resources for a specific slice, and the second information is information indicating a value of a back-off timer, and the back-off timer is a timer that is started and stopped on an S-NSSAI and PLMN (Public Land Mobile Network) basis, and when no S-NSSAI is provided by the UE together with the PDU session establishment request message, the back-off timer is started and stopped on an S-NSSAI and PLMN (Public Land Mobile Network) basis. The present invention is characterized in that the S-NSSAI is associated with the first S-NSSAI.

[0011] The communication control method for a UE (User Equipment; terminal device) of the present invention includes the steps of: transmitting a PDU (Protocol Data Unit) session establishment request message to a control device; receiving 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; receiving a PDU session change rejection message including the PDU session ID, first information, and second information from the control device; and starting a back-off timer based on reception of the PDU session change rejection message, wherein the first information is a reason value indicating that a requested service cannot be provided due to insufficient resources for a specific slice, and the second information is information indicating a value of a back-off timer, and the back-off timer is a timer that is started and stopped on an S-NSSAI and PLMN (Public Land Mobile Network) basis, and when no S-NSSAI is provided by the UE together with the PDU session establishment request message, the back-off timer is started and stopped on an S-NSSAI and PLMN (Public Land Mobile Network) basis. The present invention is characterized in that the S-NSSAI is associated with the first S-NSSAI. Effect of the Invention

[0012] According to one aspect of the present invention, terminal devices constituting 5GS and devices in a core network are characterized in that they perform management processes such as congestion management for each network slice and / or DNN, even in a state in which network slice information associated with a PDU session may be updated. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating an overview of a mobile communication system. [Diagram 2] FIG. 1 is a diagram showing an example of the configuration of an access network in a mobile communication system. [Diagram 3] A diagram showing an example of the configuration of a core network _A in a mobile communication system. [Figure 4] A diagram showing an example of the configuration of a core network _B in a mobile communication system. [Diagram 5] A diagram showing the device configuration of a UE. [Figure 6] A diagram showing the device configuration of an eNB / NR node. [Figure 7] A diagram showing the device configuration of MME / AMF. [Figure 8] A diagram showing the device configuration of SMF / PGW / UPF. [Figure 9] FIG. [Figure 10] FIG. 1 illustrates a registration procedure. [Figure 11] A diagram showing a PDU session establishment procedure. [Figure 12] A diagram showing a network-initiated session management procedure. [Figure 13] A diagram showing a UE-initiated session management procedure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will now be described with reference to the drawings. In this embodiment, as an example, an embodiment of a mobile communication system to which the present invention is applied will be described.

[0015] [1. System Overview] An overview of a mobile communication system will be described with reference to Figures 1, 2, 3, and 4. Figure 2 is a diagram showing details of an access network in the mobile communication system of Figure 1. Figure 3 is a diagram showing details of mainly a core network _A90 in the mobile communication system of Figure 1. Figure 4 is a diagram showing details of mainly a core network _B190 in the mobile communication system of Figure 1. As shown in Figure 1, the mobile communication system 1 is composed of a terminal device (also called user equipment or 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. In addition, the combination of the access network _A and the core network _A90 may be referred to as an 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 a 5GS (5G System; 5G mobile communication system), and the configuration of the 5GS and the EPS may not be limited to these. In addition, for simplification, the core network _A90, the core network B, or a combination thereof may be referred to as a core network, the access network _A, the access network _B, or a combination thereof may be referred to as an access network or a wireless access network, and the DN_A5, the PDN_A6, or a combination thereof may be referred to as a DN.

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

[0017] Furthermore, UE_A10 can be connected to an access network and / or a core network. Furthermore, 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 between DN_A and / or PDN_A 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). Furthermore, the communication of user data is not limited to IP (Internet Protocol) communication (IPv4 or IPv6), and may be, for example, non-IP communication in EPS, or Ethernet (registered trademark) communication or Unstructured communication in 5GS.

[0018] Here, IP communication refers to data communication using IP, and is data communication realized by transmitting and receiving IP packets to which an IP header is attached. The payload portion constituting the IP packet may include user data transmitted and received by UE_A10. Non-IP communication refers to data communication that does not use IP, and is data communication realized by transmitting and receiving data to which an IP header is not attached. For example, non-IP communication may be data communication realized by transmitting and receiving application data to which an IP address is not attached, or may be 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] Moreover, the 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 or a PGW (Packet Data Network Gateway), etc. Also, the PDU session may be a communication path established between UE_A10 and a core network and / or a DN for transmitting and receiving user data, or a communication path for transmitting and receiving PDUs. Furthermore, the PDU session may be a session established between UE_A10 and a core network and / or a DN, or a logical communication path consisting of one or more transfer paths such as bearers between each device in the mobile communication system 1. More specifically, the PDU session may be a connection established between UE_A10 and a core network_B190 and / or an external gateway, or a connection established between UE_A10 and a UPF. The PDU session may also be connectivity and / or a connection between UE_A10 and UPF_A235 via NR node_A122. Further, the PDU session may be identified by a PDU session ID and / or an EPS bearer ID.

[0020] In addition, UE_A10 can transmit and receive user data to and from a device such as an application server arranged in DN_A5 using a PDU session. In other words, the PDU session can transfer user data transmitted and received between UE_A10 and a device such as an application server arranged in DN_A5. Furthermore, 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 one or more identification information in association with the PDU session. In addition, these identification information may include at least one of APN (Access Point Name), TFT (Traffic Flow Template), session type, application identification information, DN_A5 identification information, NSI (Network Slice Instance) identification information, DCN (Dedicated Core Network) identification information, and access network identification information, or may further include other information. Furthermore, when multiple PDU sessions are established, each identification information associated with the PDU session may be the same or different. Furthermore, the NSI identification information is information for identifying an NSI, and may be hereinafter referred to as an NSI ID or a Slice Instance ID.

[0021] In addition, the access network _A and the access network _B may be any of UTRAN (Universal Terrestrial Radio Access Network) _A20, E-UTRAN (Evolved Universal Terrestrial Radio Access Network) _A80, and NG-RAN (5G-RAN) _A120, as shown in Fig. 2. In the following, UTRAN_A20 and / or E-UTRAN_A80 and / or NG-RAN_A120 may be referred to as 3GPP access or 3GPP access network, and a wireless LAN access network or a non-3GPP AN may be referred to as non-3GPP access or non-3GPP access network. Each wireless access network includes devices (e.g., base station devices and access points) to which UE_A10 actually connects.

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

[0023] In addition, NG-RAN_A120 is a 5G access network, and 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. In addition, NR node_A122 is a radio base station to which UE_A10 connects by 5G radio access (5G Radio Access), and is also called gNB. In addition, ng-eNB may be eNB (E-UTRA) constituting a 5G access network, and may be connected to core network_B190 via NR node_A, or may be directly connected to core network_B190. In addition, when there are multiple 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] In addition, the NG-RAN_A120 may be an access network configured with E-UTRA and / or 5G Radio Access. In other words, the NG-RAN_A120 may include an eNB_A45, an NR node_A122, or both. In this case, the eNB_A45 and the NR node_A122 may be the same device. Therefore, the NR node_A122 can be replaced with the eNB_A45.

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

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

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

[0028] Furthermore, DN_A5 and PDN_A6 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, DN_A5 may include a connected communication terminal. Therefore, connecting to DN_A5 may be connecting to a communication terminal or a server device arranged in DN_A5. Furthermore, transmitting and receiving user data to and from DN_A5 may be transmitting and receiving user data to and from a communication terminal or a server device arranged in DN_A5. Furthermore, DN_A5 is outside the core network in FIG. 1, but may be within the core network.

[0029] Furthermore, core network _A90 and / or core network _B190 may be configured as devices within one or more core networks. Here, a device within a core network may be a device that executes some or all of the processing or functions of each device included in core network _A90 and / or core network _B190. Furthermore, a device within a core network may be referred to as a core network device.

[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 DN. The core network may be a core network for a mobile communication operator that operates and manages the mobile communication system 1, or a core network for a virtual mobile communication operator such as a mobile virtual network operator (MVNO) or a mobile virtual network enabler (MVNE) or a virtual mobile communication service provider. The core network_A90 may be an Evolved Packet Core (EPC) constituting an Evolved Packet System (EPS), and the core network_B190 may be a 5G Core Network (5GC) constituting a 5GS. The core network_B190 may be a core network of a system that provides a 5G communication service. Conversely, the EPC may be the core network_A90, and the 5GC may be the core network_B190. The core network_A90 and / or the core network_B190 are not limited to this, and may be a network for providing a mobile communication service.

[0031] Next, the core network_A90 will be described. The core network_A90 may include at least one of the following: 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. These may be configured as NFs (Network Functions). NF may refer to a processing function configured within the network. The core network_A90 may also be connected to multiple radio access networks (UTRAN_A20, E-UTRAN_A80).

[0032] For simplicity, only the HSS (HSS_A50), PGW (PGW_A30), SGW (SGW_A35) and MME (MME_A40) are shown in Fig. 3, but this does not mean that other devices and / or NFs are not 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] Below is a brief explanation of each device contained within Core Network _A90.

[0034] PGW_A30 is connected to the DN, SGW_A35, ePDG, WLAN ANa70, PCRF and AAA, and is a relay device that transfers user data as a gateway between the DN (DN_A5 and / or PDN_A6) and the core network _A90. PGW_A30 may be a gateway for IP communication and / or non-IP communication. Furthermore, PGW_A30 may have a function of transferring IP communication and may have a function of converting between non-IP communication and IP communication. Furthermore, multiple such gateways may be placed in the core network _A90. Furthermore, multiple gateways may be gateways that connect the core network _A90 to a single DN.

[0035] 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 an SGW and a DN and a UPF (User plane function) and / or an SMF (Session Management Function), and 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 connected to PGW_A30, MME_A40, E-UTRAN_A80, SGSN and UTRAN_A20, and is a relay device that transfers user data as a gateway between core network_A90 and 3GPP access networks (UTRAN_A20, GERAN, E-UTRAN_A80).

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

[0039] Furthermore, when multiple MMEs are included in the core network_A90, the MMEs may be connected to each other. This allows the context of UE_A10 to be transmitted and received between the MMEs. In this manner, 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 is sufficient if it is a control device for the control plane (Control Plane; C-Plane; CP).

[0040] Furthermore, although an example has been described in which MME_A40 is configured as included in core network_A90, MME_A40 may be a management device configured in one or more core networks or DCNs or NSIs, or may be a management device connected to one or more core networks or DCNs or NSIs. Here, multiple DCNs or NSIs may be operated by a single telecommunications carrier, or may each be operated by a different telecommunications carrier.

[0041] In addition, MME_A40 may be a relay device that transfers user data as a gateway between the core network_A90 and the access network. The user data transmitted and received by MME_A40 as a gateway may be small data.

[0042] Furthermore, MME_A40 may be an NF that performs the role of mobility management for UE_A10, etc., or that manages one or more NSIs. MME_A40 may also be an NF that performs one or more of these roles. Note that an NF may be one or more devices that are placed within the 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, NF is a processing function configured in a network. That is, NF may be a functional device such as MME, SGW, PGW, CPF, AMF, SMF, UPF, etc., or may be function or capability information such as MM (Mobility Management) or SM (Session Management). Also, NF may be a functional device for realizing a single function, or may be a functional device for realizing multiple functions. For example, NF for realizing MM function and NF for realizing SM function may exist separately, or NF for realizing both MM function and 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 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] The AAA is connected to PGW30, HSS_A50, PCRF, and WLAN ANa70, and performs access control for UE_A10 connecting via WLAN ANa70.

[0047] The PCRF is connected to the PGW_A30, the WLAN ANa75, the AAA, the DN_A5 and / or the PDN_A6, and performs QoS management for data delivery. For example, it manages the QoS of the communication path between the UE_A10 and the DN_A5 and / or the PDN_A6. Furthermore, the PCRF may be a device that creates and / or manages PCC (Policy and Charging Control) rules and / or routing rules used when each device transmits and receives user data.

[0048] The PCRF may also be a PCF that creates and / or manages policies. More specifically, the PCRF may be connected to the UPF_A 235.

[0049] The ePDG is connected to the PGW 30 and WLAN ANb 75, and serves as a gateway between the core network_A 90 and WLAN ANb 75 to deliver user data.

[0050] The SGSN is connected to the UTRAN_A 20, the GERAN, and the SGW_A 35, and is a control device for location management between the 3G / 2G access network (UTRAN / GERAN) and the LTE (4G) access network (E-UTRAN). Furthermore, the SGSN has a function for selecting the PGW and SGW, a function for managing the time zone of the UE_A 10, and a function for selecting the MME_A 40 during handover to the E-UTRAN.

[0051] The SCEF is connected to DN_A5 and / or PDN_A6, MME_A40, and HSS_A50, and is a relay device that transfers user data as a gateway connecting DN_A5 and / or PDN_A6 and core network_A90. The SCEF may be a gateway for non-IP communication. Furthermore, the SCEF may have a function of converting between non-IP communication and IP communication. Furthermore, multiple such gateways may be arranged in the core network_A90. Furthermore, multiple gateways may be arranged to connect the core network_A90 to a single DN_A5 and / or PDN_A6 and / or DN. 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 AUSF (Authentication Server Function), AMF (Access and Mobility Management Function)_A240, UDSF (Unstructured Data Storage Function), NEF (Network Exposure Function), NRF (Network Repository Function), PCF (Policy Control Function), SMF (Session Management Function)_A230, UDM (Unified Data Management), UPF (User Plane Function)_A235, AF (Application Function), and N3IWF (Non-3GPP InterWorking Function). These may be configured as NF (Network Function). NF may refer to a processing function configured in the network.

[0053] For the sake of simplicity, Fig. 4 shows only the AMF (AMF_A240), SMF (SMF_A230), and UPF (UPF_A235), but this does not mean that other things (devices and / or NFs (Network Functions)) are not included. For the sake of 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, in FIG. 4, an N1 interface (hereinafter also referred to as a reference point), an N2 interface, an N3 interface, an N4 interface, an N6 interface, an N9 interface, and an N11 interface are described. Here, the N1 interface is an interface between the UE and the AMF, the N2 interface is an interface between the (R)AN (access network) and the AMF, the N3 interface is an interface between the (R)AN (access network) and the UPF, the N4 interface is an interface between the SMF and the UPF, the N6 interface is an interface between the UPF and the DN, the N9 interface is an interface between the UPF and the UPF, and the N11 interface is an interface between the AMF and the SMF. Using these interfaces, communication can be performed between each device. Here, the (R)AN is hereinafter also referred to as the NG RAN.

[0055] Below is a brief explanation of each device included in Core Network _B190.

[0056] First, the 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. The AMF_A240 may be responsible for registration management, connection management, reachability management, mobility management of UE_A10, etc., transfer of SM (Session Management) messages between the UE and SMF, access authentication, access authorization, security anchor function (SEA; Security Anchor Function), security context management (SCM; Security Context Management), support of the N2 interface for the N3IWF, support for sending and receiving NAS signals with the UE via the N3IWF, authentication of the UE connecting via the N3IWF, management of RM states (Registration Management states), management of CM states (Connection Management states), and the like. In addition, one or more AMF_A 240 may be placed in the core network _B 190. In addition, the AMF_A 240 may be an NF that manages one or more NSIs (Network Slice Instances). In addition, the AMF_A 240 may be a common CPNF (Control Plane Network Function) (CCNF) shared among multiple NSIs.

[0057] In addition, there are two RM states: the unregistered state (RM-DEREGISTERED state) and the registered state (RM-REGISTERED state). In the RM-DEREGISTERED state, the UE is not registered in the network, so the UE context in the AMF does not have valid location information or routing information for the UE, and the AMF cannot reach the UE. In the RM-REGISTERED state, the UE is registered in the network, so the UE can receive services that require registration with the network.

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

[0059] In addition, the SMF_A230 may have a session management (SM) function for PDU sessions, etc., an IP address allocation for UEs and its management function, a UPF selection and control function, a UPF setting function for routing traffic to an appropriate destination, a function for notifying that downlink data has arrived (Downlink Data Notification), a function for providing AN-specific (per AN) SM information transmitted via the N2 interface to the AN via the AMF, a function for determining a Session and Service Continuity mode (SSC mode) for the session, a roaming function, etc. In addition, the SMF_A230 may be connected to the AMF_A240, the UPF_A235, the UDM, and the PCF.

[0060] Also, UPF_A235 is connected to DN_A5, SMF_A230, other UPFs, and access networks (i.e., UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120). UPF_A235 may perform roles such as anchor for intra-RAT mobility or inter-RAT mobility, packet routing & forwarding, UL CL (Uplink Classifier) ​​function supporting routing of multiple traffic flows for one DN, Branching point function supporting multi-homed PDU session, QoS processing for user plane, verification of uplink traffic, buffering of downlink packets, trigger function of downlink data notification, etc. Also, UPF_A235 may be a relay device that forwards user data as a gateway between DN_A5 and core network_B190. Furthermore, UPF_A235 may be a gateway for IP communication and / or non-IP communication. Furthermore, UPF_A235 may have a function of forwarding IP communication and may have a function of converting non-IP communication and IP communication. Furthermore, multiple gateways may be gateways that connect Core Network_B190 to a single DN. Furthermore, UPF_A235 may have connectivity with other NFs and may be connected to each device via other NFs.

[0061] In addition, UPF_C239 (also called a branching point or uplink classifier), which is a UPF different from UPF_A235, may exist as a device or NF between UPF_A235 and the access network. 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] The AUSF is also connected to the UDM and the AMF_A 240. The AUSF functions as an authentication server.

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

[0064] The NEF provides a means to securely provision services and 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 the NF with information about the discovered NF instance and maintains information about available NF instances and the services they support.

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

[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 processes credentials, location management, subscription management, etc. The UDR stores data required for the UDM FE to provide and policy profiles required by the PCF.

[0068] The AF is connected to the PCF and is responsible for influencing traffic routing and participating in policy control.

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

[0070] The S1 mode is a UE mode capable of transmitting and receiving messages using the S1 interface. The S1 interface may be configured with an S1-MME interface, an S1-U interface, and an X2 interface that connects between radio base stations.

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

[0072] In addition, access to the EPC via an eNB that provides the E-UTRA function and access to the EPC via an en-gNB that provides the NR function are referred to as the S1 mode, but these may be configured as separate, different modes.

[0073] The N1 mode is a UE mode in which the UE can access the 5GC via the 5G access network. The N1 mode may be a UE mode in which messages can be transmitted and received using the N1 interface. The N1 interface may be configured with an Xn interface that connects the N1 interface and a radio base station.

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

[0075] In addition, access to 5GC via an ng-eNB that provides E-UTRA functionality and access to 5GC via a gNB that provides NR functionality are referred to as N1 mode, but each may be configured as a separate, different mode.

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

[0077] [1.2.1. UE Configuration] First, an example of the device configuration of UE_A10 is shown in Figure 5. As shown in Figure 5, UE_A10 is composed of a control unit _A500, a transceiver unit _A520, and a memory unit _A540. The transceiver unit _A520 and the memory unit _A540 are connected to the control unit _A500 via a bus. In addition, 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, and realizes various processing of the entire UE_A10 by reading and executing various information and programs stored in the memory unit _A540.

[0079] The transceiver unit _A520 is a functional unit for UE_A10 to connect to base stations (UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120) and / or wireless LAN access points (WLAN AN) in the access network and connect to the access network. In other words, UE_A10 can connect to base stations and / or access points in the access network via an external antenna 410 connected to the transceiver unit _A520. Specifically, UE_A10 can transmit and receive user data and / or control information between 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 UE_A10, and is composed of, for example, a semiconductor memory, a HDD (Hard Disk Drive), an SSD (Solid State Drive), etc. The memory unit _A540 stores identification information, control information, flags, parameters, rules, policies, etc. contained in control messages sent and received within the communication procedures described below.

[0081] [1.2.2. eNB / NR node] Next, an example of the device configuration of eNB_A45 and NR node_A122 is shown in Fig. 6. As shown in Fig. 6, eNB_A45 and 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. In addition, 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, and realizes various processes of the entire eNB_A45 and NR node_A122 by reading and executing various information and programs stored in the memory unit _B640.

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

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

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

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

[0087] The control unit _C700 is a functional unit for controlling the entire MME_A40 or AMF_A240, and realizes various processing of the entire AMF_A240 by reading and executing various information and programs stored in the memory unit _C740.

[0088] The network connection unit _C720 is a functional unit for connecting the MME_A40 or AMF_A240 to other MME_A40, AMF_240, SMF_A230, base stations in the access network (UTRAN_A20, E-UTRAN_A80 and NG-RAN_A120) and / or wireless LAN access points (WLAN AN), UDM, AUSF, and PCF. In other words, the MME_A40 or AMF_A240 can transmit and receive user data and / or control information between the base stations and / or access points in the access network, UDM, AUSF, and PCF via the network connection unit _C720.

[0089] The memory unit _C740 is a functional unit that stores programs and data necessary for each operation of the MME_A40 or the AMF_A240. The memory unit _C740 is composed of, for example, a semiconductor memory, a HDD, an SSD, etc. The memory unit _C740 stores identification information, control information, flags, parameters, etc. contained in a control message transmitted and received within a communication procedure described later. The context 642 stored in the memory unit _C740 may include a context stored for each UE, a context stored for each PDU session, and 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, and WAG ID. The context stored for each PDU session may include APN in Use, Assigned Session Type, IP Address(es), PGW F-TEID, SCEF ID, and Default bearer. 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, and WAG ID.

[0090] [1.2.4. Structure of SMF] Next, an example of the device configuration of SMF_A230 is shown in Figure 8. As shown in Figure 8, SMF_A230 is composed of a control unit _D800, a network connection unit _D820, and a memory unit _D840. The network connection unit _D820 and the memory unit _D840 are connected to the control unit _D800 via a bus. In addition, the memory unit _D840 stores the context 742.

[0091] The control unit _D800 of SMF_A230 is a functional unit for controlling the entire SMF_A230, and realizes various processing of the entire SMF_A230 by reading and executing various information and programs stored in the memory unit _D840.

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

[0093] Moreover, the memory unit _D840 of the SMF_A230 is a functional unit that stores programs and data necessary for each operation of the SMF_A230. The memory unit _D840 of the SMF_A230 is composed of, for example, a semiconductor memory, a HDD, an SSD, etc. The memory unit _D840 of the SMF_A230 stores identification information, control information, flags, parameters, etc. included in a control message transmitted and received within a communication procedure described later. Furthermore, the context 742 stored in the memory unit _D840 of the SMF_A230 may include 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. In addition, the context stored for each APN may be stored for each Data Network Identifier. The context stored per PDU session may include Assigned Session Type, IP Address(es), SGW F-TEID, PGW F-TEID, Default Bearer. The context stored per bearer may include EPS Bearer ID, TFT, SGW F-TEID, PGW F-TEID.

[0094] [1.2.5. PGW / UPF configuration] Next, an example of the device configuration of PGW_A30 or UPF_A235 is shown in Figure 8. As shown in Figure 8, PGW_A30 or UPF_A235 is respectively composed of a control unit _D800, a network connection unit _D820, and a memory unit _D840. The network connection unit _D820 and the memory unit _D840 are connected to the control unit _D800 via a bus. In addition, the memory 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, and realizes various processing of the entire PGW_A30 or UPF_A235 by reading and executing various information and programs stored in the memory unit _D840.

[0096] Furthermore, the network connection unit _D820 of PGW_A30 or UPF_A235 is a functional unit for connecting PGW_A30 or UPF_A235 to the DN (i.e., DN_A5), SMF_A230, other UPF_A235, and access networks (i.e., UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120). In other words, UPF_A235 can transmit and receive user data and / or control information between the DN (i.e., DN_A5), SMF_A230, other UPF_A235, and access networks (i.e., UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120) via the network connection unit _D820.

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

[0098] [1.2.6. Information stored in the memory 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 a permanent identification information of a subscriber (user) and is an identification information assigned to a user who uses a UE. The IMSI stored by UE_A10 and MME_A40 / CPF_A140 / AMF_A2400 and SGW_A35 may be equal to the IMSI stored by HSS_A50.

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

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

[0102] The MME F-TEID is information for identifying the MME_A40 / CPF_A140 / AMF_A240. The MME F-TEID may include an IP address of the MME_A40 / CPF_A140 / AMF_A240, or may include a TEID (Tunnel Endpoint Identifier) ​​of the MME_A40 / CPF_A140 / AMF_A240, or may include both of these. In addition, the IP address of the MME_A40 / CPF_A140 / AMF_A240 and the TEID of the MME_A40 / CPF_A140 / AMF_A240 may be stored independently. In addition, 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 the SGW_A35. The SGW F-TEID may include the IP address of the SGW_A35, may include the TEID of the SGW_A35, or may include both. The IP address of the SGW_A35 and the TEID of the SGW_A35 may be stored independently. 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 an IP address of PGW_A30 / UPGW_A130 / SMF_A230 / UPF_A235, may include a TEID of PGW_A30 / UPGW_A130 / SMF_A230 / UPF_A235, or may include both of these. In addition, 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. In addition, the PGW F-TEID may be identification information for user data or identification information for control information.

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

[0106] Moreover, the APN may be identification information for identifying a core network and an external network such as a DN. Furthermore, the APN may be used as information for selecting a gateway such as PGW_A30 / UPGW_A130 / UPF_A235 that connects the core network A_90. The APN may be a DNN (Data Network Name). Therefore, the APN may be expressed as a DNN, and the DNN may be expressed as an APN.

[0107] The APN may be identification information for identifying such a gateway, or may be identification information for identifying an external network such as a DN. When multiple gateways are installed to connect the core network and the DN, multiple gateways may be selectable by the APN. Furthermore, one gateway may be selected from the multiple gateways 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 by SGSN_A42 for UE_A10 with 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 that identifies UE_A10 within MME_A40 / CPF_A140 / AMF_A240. eNB UE S1AP ID is information that identifies UE_A10 within eNB_A45.

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

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

[0111] Furthermore, 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 if the Assigned Session Type indicates non-IP, the IP Address element does not have to be included.

[0112] The DN ID is identification information that identifies the core network _B190 and an external network such as DN. Furthermore, the DN ID can also be used as information to select a gateway such as UPGW_A130 or PF_A235 that connects the core network _B190.

[0113] The DN ID may be identification information for identifying such a gateway, or may be identification information for identifying an external network such as a DN. If multiple gateways are installed to connect the core network_B190 and the DN, there may be multiple gateways that can be selected 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 may be information different from the APN. If 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 to inquire about the APN using the DN ID, or may perform a procedure to inquire about 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 acquired and / or generated when the PDU session is established, and is EPS bearer identification information for identifying the default bearer associated with the PDU session.

[0116] The EPS Bearer ID is identification information of the EPS bearer. The EPS Bearer ID may be identification information for identifying an SRB (Signalling Radio Bearer) and / or a CRB (Control-plane Radio Bearer), or may be identification information for identifying a DRB (Data Radio Bearer). The TI (Transaction Identifier) ​​is identification information for identifying a bidirectional message flow (Transaction). The EPS Bearer ID may be EPS bearer identification information for identifying a dedicated bearer. Therefore, it may be identification information for identifying an EPS bearer different from the default bearer. The TFT indicates all packet filters associated with the EPS bearer. The TFT is information for identifying a portion 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 an RB (Radio Bearer) associated with the TFT. In addition, the TFT may correspond to an appropriate transmission path for user data such as application data to be transmitted and received, or may be identification information for identifying application data. In addition, the UE_A10 may transmit and receive user data that cannot be identified by the TFT using a default bearer. In addition, the UE_A10 may store in advance a TFT associated with the default bearer.

[0117] The Default Bearer is EPS bearer identification information for identifying a default bearer associated with a PDU session. The EPS bearer may be a logical communication path established between UE_A10 and PGW_A30 / UPGW_A130 / UPF_A235, or may be a communication path constituting a PDN connection / PDU session. The EPS bearer may be a default bearer or a dedicated bearer. The EPS bearer may include an RB established between UE_A10 and a base station and / or an access point in an access network. The RB and the EPS bearer may be in one-to-one correspondence. Therefore, the identification information of the RB may be in one-to-one correspondence with the identification information of the EPS bearer, or may be the same identification information. The RB may be an SRB and / or a CRB, or may be a DRB. Moreover, the Default Bearer may be information that UE_A10 and / or SGW_A35 and / or PGW_A30 / UPGW_A130 / SMF_A230 / UPF_A235 acquire from the core network when the PDU session is established. The default bearer is an EPS bearer that is established first in a PDN connection / PDU session, and only one EPS bearer can be established in one PDN connection / PDU session. The default bearer may be an EPS bearer that can be used for communication of user data that is not associated with a TFT. The dedicated bearer is an EPS bearer that is established after the default bearer is established in a PDN connection / PDU session, and a plurality of EPS bearers can be established in one PDN connection / PDU session. The dedicated bearer is an EPS bearer that can be used for communication of user data associated with a TFT.

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

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

[0120] An anchor, or anchor point, is a UFP that has a gateway function between a DN and a PDU session. A UFP that is an anchor point may be a PDU session anchor or an anchor.

[0121] In 5GC, the SSC mode indicates a mode of service session and service continuity supported by the system and / or each device. More specifically, the SSC mode may be a mode indicating a type of service session continuity supported by a PDU session established between the UE_A10 and an anchor point. Here, the anchor point may be the UPGW or the UPF_A235. The SSC mode may be a mode indicating a 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 service session continuity mode in which the same UPF is maintained as the anchor point regardless of the access technology, such as the RAT (Radio Access Technology) or cell, that UE_A10 uses when connecting 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 service session continuation mode in which, when a PDU session includes an anchor point associated with one SSC mode 2, the PDU session is first released and then established. More specifically, SSC mode 2 is a mode in which, when an anchor point relocation occurs, the PDU session is deleted once and then a new PDU session is established.

[0124] Furthermore, SSC mode 2 is a service session continuity mode in which the same UPF is maintained as an 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 as moving out of 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 an access network such as a RAT or a cell used when UE_A10 connects to a 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 service session continuity mode in which a PDU session between a UE and an anchor point can be established for the same DN between the UE and the anchor point without releasing the PDU session between the UE and the anchor point.

[0127] Furthermore, SSC mode 3 is a service session continuity mode that allows a new PDU session and / or communication path to be established 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 service session continuity mode that allows UE_A10 to be multi-homing.

[0128] And / or, SSC mode 3 may be a mode in which service session continuity using multiple 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 realize service session continuity using multiple PDU sessions, or may realize service session continuity using multiple 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, and the new UPF may be the UPF that is optimal for the location where UE_A10 connects to the network. Furthermore, when multiple PDU sessions and / or the UPF 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 do so based on the completion of the communication.

[0130] [1.3. Explanation of initial procedures] Next, before describing the detailed procedure of the initial procedure, in order to avoid repetitive explanation, specific terms and main identification information used in each procedure will be described in advance.

[0131] The network refers to at least a portion of the access network _A20 / 80, the access network _B80 / 120, the core network _A90, the core network _B190, the DN_A5, and the PDN_A6. In addition, one or more devices included in at least a portion of the access network _A20 / 80, the access network _B80 / 120, the core network _A90, the core network _B190, the DN_A5, and the PDN_A6 may be referred to as a network or a network device. In other words, when a network transmits and receives messages and / or performs procedures, it means that a device (network device) in the network transmits and receives messages and / or performs procedures.

[0132] A Session Management (SM) message (also referred to as a Non-Access-Stratum (NAS) SM message or SM message) may be a NAS message used in a procedure for SM (also referred to as a Session Management procedure or SM procedure), and may be a control message transmitted and received between UE_A10 and SMF_A230 via AMF_A240. Furthermore, the SM message may include a PDU session establishment request message, a PDU session establishment acceptance message, a PDU session completion message, a PDU session establishment rejection message, a PDU session change request message, a PDU session change acceptance message, a PDU session change rejection message, etc. Furthermore, the procedure for SM may include a PDU session establishment procedure, a PDU session change procedure, etc.

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

[0134] A tracking area (TA) is a range managed by the core network that can be represented by the location information of UE_A10, and may be composed of, for example, one or more cells. A TA may also 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 includes one or more TAs that the network has assigned 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 that indicates areas in which 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 a NW slice.

[0137] An NSI (Network Slice Instance) is an entity of a network slice, one or more of which are configured in the core network _B190. The NSI may also be configured by a virtual NF (Network Function) generated using an NST (Network Slice Template). Here, the NST is associated with a resource requirement for providing a required communication service or capability, and is a logical expression of one or more NFs (Network Functions). In other words, the NSI may be a collection in the core network _B190 configured by multiple NFs. The NSI may also be a logical network configured to separate user data delivered by services, etc. At least one or more NFs may be configured in the network slice. The NF configured in the network slice may or may not be a device shared with other network slices. 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 and / or APN.

[0138] S-NSSAI is an 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. SD may be information that complements SST when selecting one NSI from multiple NSIs indicated by SST. S-NSSAI may be information specific to each PLMN (Public Land Mobile Network), standard information common among PLMNs, or carrier-specific information different for each PLMN.

[0139] More specifically, the SST and / or SD may be standard information (Standard Value) common among PLMNs, or may be carrier-specific information (Non Standard Value) that differs for each PLMN. In addition, the network may store one or more S-NSSAIs in the registration information of UE_A10 as a default S-NSSAI.

[0140] NSSAI (Single Network Slice Selection Assistance information) is a collection of S-NSSAI. Each S-NSSAI included in the NSSAI is information that assists the access network or core network in selecting an NSI. UE_A10 may store the NSSAI allowed by the network for each PLMN. The NSSAI may also 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 NW slice in common with operator B, which will be described later.

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

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

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

[0145] An equivalent PLMN is a PLMN that is treated by the network as if it were the same PLMN as any other PLMN.

[0146] A DCN (Dedicated Core Network) is a core network dedicated to a specific subscriber type, one or more of which are configured within the core network _A90. Specifically, for example, a DCN for a UE registered as a user of an M2M (Machine to Machine) communication function may be configured within the core network _A90. In addition, a default DCN for a UE that does not have an appropriate DCN may be configured within the core network _A90. Furthermore, at least one or more MMEs_40 or SGSNs_A42 may be configured in the DCN, and at least one or more SGWs_A35s, PGWs_A30s, or PCRFs_A60s may be configured. In addition, the DCN may be identified by a DCN ID, and a UE may be assigned to one DCN based on information such as a UE usage type and / or a DCN ID.

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

[0148] In addition, the SM message may be a NAS message used in a procedure for session management, and may be a control message transmitted and received between UE_A10 and SMF_A230 via AMF_A240. Furthermore, the SM message may include a PDU session establishment request message, a PDU session establishment acceptance message, a PDU session completion message, a PDU session establishment rejection message, a PDU session change request message, a PDU session change acceptance message, a PDU session change rejection message, etc. Furthermore, the procedure for session management may include a PDU session establishment procedure, a PDU session change procedure, etc. In addition, in these procedures, a back-off timer value may be included for each message received by UE_A10. The UE may set the back-off timer received from the NW as the first timer, may set the timer value in another manner, or may set a random value. Also, when the back-off timer received from the NW is composed of multiple timers, the UE may manage multiple "first timers" corresponding to the multiple back-off timers, or may select one timer value from the multiple back-off timer values ​​received from the NW based on a policy held by the UE, set it to the first timer, and manage it. For example, when two back-off timer values ​​are received, the UE sets the back-off timer values ​​received from the NW to "first timer #1" and "first timer #2", respectively, and manages them. Also, the UE may select one value from the multiple back-off timer values ​​received from the NW based on a policy held by the UE, set it to the first timer, and manage it.

[0149] When UE_A10 receives multiple back-off timer values ​​from the NW, it may manage multiple "first timers" corresponding to the multiple back-off timers. Here, in order to distinguish the multiple "first timers" received by UE_A10, they may be described below as, for example, "first timer #1" or "first timer #2." Note that the multiple back-off timers may be obtained in a single session management procedure, or may be obtained in different session management procedures.

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

[0151] The re-attempt (Re-attempt) information contained in the 11th identification information is information instructing UE_A10 by the network (NW) whether to allow reconnection using the same DNN information and / or S-NSSAI information for a rejected PDU session establishment request (S1100).

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

[0153] Furthermore, the re-attempt information may be set on a UTRAN access and / or E-UTRAN access and / or NR access and / or slice information and / or uniform PLMN and / or S1 mode and / or NW mode basis.

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

[0155] Furthermore, the re-attempt information specified in uniform PLMN units may be information indicating that reconnection using the same information is permitted if the destination PLMN is a uniform PLMN when changing PLMNs, or information indicating that reconnection using this procedure is not permitted if the destination PLMN is not a uniform PLMN.

[0156] Furthermore, the re-attempt information specified on a mode basis (S1 mode, N1 mode) may be information indicating that reconnection using the same information is permitted if the changed mode is S1 mode when the mode is changed, or information indicating that reconnection using the same information is not permitted if the changed mode is S1 mode.

[0157] A network slice association rule is a rule that associates information that identifies multiple network slices. The network slice association rule may be received in a PDU session establishment rejection message or may be set in advance in UE_A10. 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 network slice association rule is set in advance in UE_A10 and a new network slice association rule is received in a PDU session establishment rejection message, UE_A10 may update the network slice association rule held in UE_A10.

[0158] The priority management rule of the back-off timer is a rule set in the UE_A10 to manage multiple back-off timers that occur in multiple PDU sessions as one back-off timer. For example, when conflicting or overlapping congestion management is applied and the UE holds multiple back-off timers, the UE_A10 may manage the multiple back-off timers together based on the priority management rule of the back-off timer. In addition, a pattern in which conflicting or overlapping congestion management occurs is when congestion management based only on DNN and congestion management based on both DNN and slice information are applied simultaneously, in which case congestion management based only on DNN is prioritized. In addition, the priority management rule of the back-off timer may not be limited to this. In addition, the back-off timer may be a 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 has applied one or more of the first to fourth congestion management methods. Here, UE_A10 and / or each device may be in a state in which UE_A10 is registered in the network (RM-REGISTERED state) upon completion of the registration procedure, and 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] The congestion management is composed of one or more of the congestion managements from the first congestion management to the fourth congestion management. 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 store the association of these pieces of information.

[0161] The first congestion management refers to control signal congestion management targeting the parameters of the DNN. For example, in the case where congestion for the DNN#A is detected in the NW, if the NW recognizes that the UE-initiated session management request is targeting the parameters of only the DNN#A, the NW may apply the first congestion management. In addition, even if the UE-initiated session management request does not include DNN information, the NW may select a default DNN at the initiative of the NW and set it as a congestion management target. Alternatively, even if the NW recognizes that the UE-initiated session management request includes the DNN#A and the S-NSSAI#A, the NW may apply the first congestion management. When the first congestion management is applied, the UE may suppress the UE-initiated session management request targeting only the DNN#A.

[0162] In other words, the first congestion management may be control signal congestion management targeted at the DNN, and may be congestion management caused by the connectivity to the DNN being in a congested state. For example, the first congestion management may be congestion management for regulating the connection to the DNN#A in all connectivity. Here, the connection to the DNN#A in all connectivity may be the connection to the DNN#A in the connectivity using any S-NSSAI available to the UE, or the connection to the DNN#A via a network slice to which the UE can connect. Furthermore, the connectivity to the DNN#A not via a network slice may be included.

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

[0164] In other words, the second congestion management may be a control signal congestion management targeted at the S-NSSAI, and may be congestion management caused by the network slice selected by the S-NSSAI being in a congested state. For example, the second congestion management may be congestion management for regulating all connections based on the S-NSSAI#A. That is, it may be congestion management for regulating connections to all DNNs via the network slice selected by the S-NSSAI#A.

[0165] The third congestion management refers to control signal congestion management targeting the parameters of DNN and S-NSSAI. For example, in a case where a control signal congestion for DNN#A and a control signal congestion for S-NSSAI#A are detected simultaneously in a NW, and the NW recognizes that the request is a UE-initiated session management request targeting the parameters of DNN#A and S-NSSAI#A, the NW may apply the third congestion management. In addition, even if the UE-initiated session management request does not include information indicating a DNN, the NW may select a default DNN at the initiative of the NW and set it as a congestion management target. When the third congestion 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 congestion management may be a control signal congestion management targeting the parameters of the DNN and the S-NSSAI, and may be congestion management caused by the connectivity to the DNN via the network slice selected based on the S-NSSAI being in a congested state. For example, the third congestion management may be congestion management for regulating the connection to the DNN#A among the connectivity based on the S-NSSAI#A.

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

[0168] In other words, the fourth congestion management may be a control signal congestion management targeting the parameters of the DNN and the S-NSSAI, and may be congestion management caused by the network slice selected based on the S-NSSAI and the connectivity to the DNN being in a congested state. For example, the fourth congestion management may be congestion management for restricting all connections based on the S-NSSAI#A, and congestion management for restricting connections to the DNN#A in all connectivity. That is, it may be congestion management for restricting connections to all DNNs via a network slice selected by the S-NSSAI#A, and congestion management for restricting connections to the DNN#A in all connectivity. Here, the connection to the DNN#A in all connectivity may be a connection to the DNN#A in connectivity using any S-NSSAI available to the UE, or a connection to the DNN#A via a network slice to which the UE can connect. Furthermore, it may include connectivity to the DNN#A not via a network slice.

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

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

[0171] The second behavior is a behavior in which the UE transmits a PDU session establishment request to connect to the same APN / DNN as the first PDU session establishment request using slice information different from the slice information specified in the first PDU session establishment. Specifically, the second behavior may be a behavior in which the UE transmits a PDU session establishment request to connect to the same APN / DNN as the first PDU session establishment request using slice information different from the slice information specified in the first PDU session establishment when the back-off timer value received from the network is zero or invalid. In addition, when the first PDU session is rejected because 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 a temporary reason, the UE may transmit a PDU session establishment request to connect to the same APN / DNN as the APN / DNN included in the first PDU session establishment request using slice information different from the slice information specified in the first PDU session establishment.

[0172] The third behavior is a behavior in which the UE does not transmit a new PDU session establishment request using the same identification information until the first timer expires when the PDU session establishment request is rejected. Specifically, the third behavior may be a behavior in which the UE does not transmit a new PDU session establishment request using the same identification information until the first timer expires when the back-off timer value received from the network is neither zero nor invalid. Here, the same identification information may mean that the first identification information and / or the second identification information to be included in the new PDU session establishment request are the same as the first identification information and / or the second identification information transmitted in the rejected PDU session establishment request.

[0173] Furthermore, if another PLMN is selected, or another NW slice is selected, and a rejection reason related to a network operation configuration failure is received, if the back-off timer received when the first PDU session establishment request was rejected is activated, the behavior may be such that a new PDU session establishment request using the same identification information is not sent until the first timer expires.

[0174] In detail, the PDU session that does not transmit 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, the connectivity according to the type of congestion management associated with the first timer may be a behavior that does not transmit a new PDU session establishment request for a PDU session using a DNN and / or S-NSSAI associated with the congestion management. Note that the process that the UE is prohibited from by this behavior may be the start of a procedure for session management including a PDU session establishment request, and / or the transmission and reception of an SM message.

[0175] The fourth behavior is a behavior in which the UE does not transmit a new PDU session establishment request that does not include slice information and DNN / APN information until the first timer expires when the PDU session establishment request is rejected. Specifically, the fourth behavior may be a behavior in which the UE does not transmit a new PDU session establishment request that does not include slice information and DNN / APN information until the first timer expires when the back-off timer received by the UE from the network is neither zero nor invalid.

[0176] The fifth behavior is a behavior in which the UE does not transmit a new PDU session establishment request using the same identification information when the PDU session establishment request is rejected. Specifically, the fifth behavior may be a behavior in which the UE does not transmit a new PDU session establishment request using the same identification information when the UE and the network support different PDP types and the UE reside in an equal PLMN.

[0177] The sixth behavior is a behavior of the UE sending a new PDU session establishment request as an initial procedure using the same identification information when the PDU session establishment request is rejected. Specifically, the sixth behavior may be a behavior of the UE sending a new PDU session establishment request as an initial procedure using the same identification information when the first PDU session establishment request is rejected due to the absence of a target PDN session context in a handover from a non-3GPP access.

[0178] The seventh behavior is a behavior in which, when the UE selects another NW slice in the procedure for selecting a PLMN, the UE continues the back-off timer received when the previous PDU session establishment request was rejected. Specifically, the seventh behavior may be a behavior in which, when the UE selects a PLMN when the first PDU session establishment request is rejected, the UE continues the back-off timer received when the first PDU session establishment request is rejected if the UE can specify a NW slice common to the NW slice specified in the first PDU session establishment request in the selected PLMN.

[0179] The eighth behavior is a behavior in which the UE sets the first timer value to a value notified from the network or a value previously set in the UE. Specifically, the eighth behavior may be a behavior in which the UE sets the back-off timer value received in a rejection notification of the first PDU session establishment request as the first timer value, or may be a behavior in which the UE sets the first timer value to a value previously set or held in the UE. Note that the case in which the UE sets the first timer value to a timer previously set or held in the UE may be limited to when the UE is in the coverage area of ​​an HPLMN or an equalized PLMN.

[0180] The ninth behavior is a behavior in which the UE does not transmit a new PDU session establishment request until the terminal power is turned on / off or the USIM (Universal Subscriber Identity Module) is removed and inserted when the PDU session establishment request is rejected. Specifically, the ninth behavior is a behavior in which the UE does not transmit a new PDU session establishment request until the terminal power is turned on / off or the USIM is removed and inserted when the back-off timer received from the network is invalid or the first PDU session rejection reason is different PDP types between the UE and the network. In addition, when the first PDU session establishment request is rejected because the specified APN / DNN is not supported by the radio of the connected PLMN, there is no back-off timer information element from the network, there is no Re-attempt information, or PDU session reconnection to an equal PLMN is allowed, the UE may be configured not to transmit a new PDU session establishment request in the connected PLMN until the terminal power is turned on / off or the USIM is removed and inserted. Also, if the first PDU session establishment request is rejected because the specified APN / DNN is not supported by the radio of the connected PLMN, and if there is no back-off timer information element from the network and no Re-attempt information, or if PDU session reconnection to an equal PLMN is not permitted, the connected PLMN may not transmit a new PDU session establishment request until the terminal is powered on / off or the USIM is removed and reinserted.Also, if the first PDU session establishment request is rejected because the specified APN / DNN is not supported by the radio of the connected PLMN, and if the back-off timer from the network is neither zero nor invalid, the connected PLMN may not transmit a new PDU session establishment request until the terminal is powered on / off or the USIM is removed and reinserted.In addition, if the first PDU session establishment request is rejected because the specified APN / DNN is not supported by the radio of the connected PLMN, and the back-off timer from the network is disabled, the behavior may be such that a new PDU session establishment request is not sent until the terminal is powered on / off or the USIM is removed and inserted.

[0181] The tenth behavior is a behavior of the UE sending a new PDU session establishment request when the PDU session establishment request is rejected. Specifically, the tenth behavior may be a behavior of the UE sending a new PDU session establishment request when the back-off 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 back-off timer information element notified from the network. Also, the tenth behavior may be a behavior of sending a new PDU session establishment request when another PLMN is selected or another NW slice is selected, the first PDU session establishment request is rejected for a temporary reason, and the back-off timer for the target APN / DNN in the selected PLMN is not activated, or when the back-off timer received from the network is invalid. Alternatively, 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, re-attempt information is not received, or a PLMN not in the uniform PLMN list is selected, or the PDP type is changed, or the terminal is powered on / off, or the USIM is removed and inserted, a new PDU session establishment request may be transmitted.Also, when the first PDU session establishment request is rejected because the specified APN / DNN is not supported by the radio of the connected PLMN, and the back-off timer notified from the network is zero, a new PDU session establishment request may be transmitted.

[0182] The eleventh behavior is a behavior in which the UE ignores the first timer and the Re-attempt information. Specifically, the eleventh behavior may be a behavior in which the UE ignores the first timer and the Re-attempt information when the first PDU session establishment request is rejected in a handover from a non-3GPP access because the target PDN session context does not exist, or when the first PDU session establishment is rejected because the number of bearers established in the PDN connection reaches the maximum allowed number.

[0183] The twelfth behavior is a behavior in which the UE determines information for identifying multiple associated NW slices based on information for identifying one NW slice received in a rejection notification for the first PDU session establishment request, and suppresses reconnection to the multiple associated NW slices based on the information for identifying one NW slice. Specifically, the twelfth behavior may be a behavior in which the UE derives 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 a 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 a rejection notification for the PDU session establishment.

[0184] The thirteenth behavior may be a behavior in which, when multiple different congestion managements are activated for one or multiple PDU session establishments by the same UE and multiple timers are provided from the network, the UE manages the timers based on a priority management rule for the back-off timer. For example, a first PDU session establishment request by the UE for a combination of DNN_1 and slice_1 is subject to congestion management based on both DNN and slice information, and the UE receives the first timer #1. Furthermore, the UE makes a second PDU session establishment request for a combination of DNN_1 and slice_2, which is subject to congestion management based only on DNN, and receives the first timer #2. At this time, the UE may manage the behavior of the PDU session re-establishment by the prioritized first timer #2 based on the priority management rule for the back-off timer. Specifically, the timer value generated by the prioritized congestion control may be overwritten by the timer value held by the UE.

[0185] The fourteenth behavior may be a behavior of managing timers for each session management instance (PDU session unit) when multiple different congestion managements are applied to one or multiple PDU session establishments by the same UE and multiple timers are provided from the network. For example, when the first PDU session establishment by the UE for the combination of DNN#1 and slice#1 is determined to be a congestion target based on both the DNN and slice information, the UE manages the target back-off timer value as the first timer#1. After that, when the UE attempts to establish a PDU session for the combination of DNN#1 and slice#2 as a second PDU session, if the session is determined to be a congestion target based only on the DNN, the UE manages the target back-off timer value as the first timer#2. At this time, the UE simultaneously manages multiple timers (here, the first timer#1 and the first timer#2). Specifically, the UE manages timers for each session management instance / PDU session. Also, when the UE receives multiple timers simultaneously in one session management procedure, the UE simultaneously manages the target back-off timers for the congestion management unit identified by the UE.

[0186] The fifteenth behavior may be a behavior in which UE_A10 executes a first identification process for identifying which type of congestion management to apply among the first congestion management to the fourth congestion management, and a second identification process for identifying a DNN and / or an S-NSSAI associated with the congestion management to be applied. The first identification process may be based on at least one or more identification information of the first identification information to the fourth identification information, and / or at least one or more identification information of the eleventh identification information to the eighteenth identification information. Similarly, the second identification process may be based on at least one or more identification information of the first identification information to the fourth identification information, and / or at least one or more identification information of the eleventh identification information to the eighteenth identification information.

[0187] An example of the first identification process will be described below. 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 first congestion management. At least the 15th identification information is a value corresponding to the first congestion management. At least the 16th identification information is a value corresponding to the first congestion management. At least, the 14th identification information includes information indicating the first congestion management. At least, if the 17th identification information contains only DNN and does not contain S-NSSAI. When the 16th identification information is information for identifying either the first congestion management or the second congestion management and only a value corresponding to the second congestion management can be set to the 16th identification information, at least the 16th identification information has not been received. When the 16th identification information is information for identifying either the first congestion management or the fourth congestion management and only a value corresponding to the fourth congestion management can be set to the 16th identification information, at least the 16th identification information has not been received. When the 16th identification information is information for identifying one of the first congestion management, the second congestion management, and the fourth congestion management, and only a value corresponding to the second congestion management and a value corresponding to the fourth congestion management can be set to the 16th identification information, at least the 16th identification information has not been received.

[0188] However, without being limited to the above example, UE_A10 may be identified based on at least one or more identification information from the first identification information to the fourth identification information, and / or at least one identification information from the eleventh identification information to the eighteenth identification information, or a combination of two or more identification information.

[0189] 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 second congestion management. At least the 15th identification information is a value corresponding to the second congestion management. At least the 16th identification information is a value corresponding to the second congestion management. At least the 14th identification information includes information indicating the second congestion management. At least, if the 17th identification information contains only S-NSSAI and does not contain DNN. When the 16th identification information is information for identifying either the first congestion management or the second congestion management and only a value corresponding to the first congestion management can be set to the 16th identification information, at least the 16th identification information has not been received. When the 16th identification information is information for identifying either the second congestion management or the third congestion management and only a value corresponding to the third congestion management can be set to the 16th identification information, at least the 16th identification information has not been received. When the 16th identification information is information for identifying one of the second congestion management, the third congestion management, and the fourth congestion management, and only a value corresponding to the third congestion management and a value corresponding to the fourth congestion management can be set to the 16th identification information, and at least the 16th identification information has not been received.

[0190] However, without being limited to the above example, UE_A10 may be identified based on at least one or more identification information from the first identification information to the fourth identification information, and / or at least one identification information from the eleventh identification information to the eighteenth identification information, or a combination of two or more 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. At least the 15th identification information is a value corresponding to the third congestion management. At least the 16th identification information is a value corresponding to the third congestion management. At least, the 14th identification information includes information indicating the third congestion management. At least, the 15th identification information is a value corresponding to multiple congestion managements including the third congestion management and not including the fourth congestion management, and the 17th identification information includes S-NSSAI and DNN. When the 16th identification information is information for identifying either the third congestion management or the fourth congestion management and only a value corresponding to the fourth congestion management can be set to the 16th identification information, at least the 16th identification information has not been received. When the 16th identification information is information for identifying either the second congestion management or the third congestion management and only a value corresponding to the second congestion management can be set to the 16th identification information, at least the 16th identification information has not been received. When the 16th identification information is information for identifying one of the second congestion management, the third congestion management, and the fourth congestion management, and only a value corresponding to the second congestion management and a value corresponding to the fourth congestion management can be set to the 16th identification information, at least the 16th identification information has not been received.

[0192] However, without being limited to the above example, UE_A10 may be identified based on at least one or more identification information from the first identification information to the fourth identification information, and / or at least one identification information from the eleventh identification information to the eighteenth identification information, or a combination of two or more identification information.

[0193] 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 fourth congestion management. At least, the 15th identification information is a value corresponding to the 4th congestion management. At least, the 16th identification information is a value corresponding to the 4th congestion management. At least, the 14th identification information includes information indicating the 4th congestion management. At least, the 15th identification information is a value corresponding to multiple congestion managements, including the 4th congestion management and not including the 3rd congestion management, and the 17th identification information includes S-NSSAI and DNN. When the 16th identification information is information for identifying either the third congestion management or the fourth congestion management and only a value corresponding to the third congestion management can be set to the 16th identification information, at least the 16th identification information has not been received. When the 16th identification information is information for identifying either the second congestion management or the fourth congestion management and only a value corresponding to the second congestion management can be set to the 16th identification information, at least the 16th identification information has not been received. When the 16th identification information is information for identifying either the first congestion management or the fourth congestion management and only a value corresponding to the first congestion management can be set to the 16th identification information, at least the 16th identification information has not been received. When the 16th identification information is information for identifying one of the second congestion management, the third congestion management, and the fourth congestion management, and only a value corresponding to the second congestion management and a value corresponding to the third congestion management can be set to the 16th identification information, and at least the 16th identification information has not been received. When the 16th identification information is information for identifying one of the first congestion management, the second congestion management, and the fourth congestion management, and only a value corresponding to the first congestion management and a value corresponding to the second congestion management can be set to the 16th identification information, and at least the 16th identification information has not been received.

[0194] However, without being limited to the above example, UE_A10 may be identified based on at least one or more identification information from the first identification information to the fourth identification information, and / or at least one identification information from 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.

[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. The second identification process may be a process of identifying a 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 congestion management, the third congestion management, and the fourth congestion management may be determined based on the twelfth identification information. And / or, the DNNs corresponding to the first congestion management, the third congestion management, and the fourth congestion management may be determined based on the seventeenth identification information. And / or, the DNNs corresponding to the first congestion management, the third congestion management, and the fourth congestion management may be determined based on the second identification information.

[0198] Therefore, the DNNs corresponding to the first congestion management, the third congestion management, and the fourth congestion management may be the DNNs indicated by the 12th identification information. And / or, the DNNs corresponding to the first congestion management, the third congestion management, and the fourth congestion management may be the DNNs included in the 17th identification information. And / or, the DNNs corresponding to the first congestion management, the third congestion management, and the fourth congestion management may be the DNNs indicated by the second identification information.

[0199] In addition, the S-NSSAI corresponding to the second congestion management, the third congestion management, and the fourth congestion management may be determined based on the seventeenth identification information. And / or, the DNN corresponding to the first congestion management, the third congestion management, and the fourth congestion management may be determined based on the first identification information.

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

[0201] However, without being limited to the above example, UE_A10 may be identified based on at least one or more identification information from the first identification information to the fourth identification information, and / or at least one identification information from 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 that core network _B190 applies to UE_A10. In other words, based on the 15th behavior, UE_A10 may identify the type of congestion management and the corresponding S-NSSAI and / or DNN as the congestion management to be applied. In addition, UE_A10 may store and manage one or more identification information among the first identification information to the fourth identification information and the 11th identification information to the 18th identification information in association with the congestion management to be applied. Here, the third identification information, and / or the fourth identification information, and / or the 13th identification information may be stored and managed as information identifying the congestion management to be applied.

[0203] The sixteenth behavior is a behavior of stopping the first timer when a network-initiated session management procedure is executed while the UE has started the first timer.

[0204] Here, for example, when multiple first timers are activated, the behavior may be to determine a first timer to be stopped from among the activated multiple first timers based on the 21st identification information, and to stop the timer. And / or the behavior may be to stop the first timer associated with the congestion management identified by the 17th behavior. Note that, when there are multiple congestion managements identified by the 17th behavior, the timers associated with each congestion management may be stopped.

[0205] The 17th behavior may be a behavior of the UE that identifies, based on receipt of a control message transmitted by the core network, one or more congestion managements that the UE is currently applying, which congestion management to stop applying. For example, the UE may identify, based on the 21st identification information, which congestion management to stop applying or change.

[0206] Specifically, as described above, in the fourth process, the UE stores the third identification information, and / or the fourth identification information, and / or the thirteenth identification information, etc., as information for identifying congestion management, and may identify these congestion managements whose identification information matches the thirteenth identification information included in the twenty-first identification information as the congestion management to be stopped being applied.

[0207] And / or, the UE may identify the congestion management to be stopped based on one or more combinations of the 11th identification information to the 18th identification information included in the 21st identification information. Here, the details of the identification method may be the same as the identification process in the 15th behavior described in the fourth process in the example of the PDU session establishment procedure described later. In other words, the UE may identify the congestion management to be stopped in the same manner as the method of identifying the congestion management to be applied.

[0208] In addition, the UE may identify multiple congestion managements to stop applying. In the following, the congestion management identified by the above-mentioned method is defined as a first congestion management, and a method of identifying a second congestion management different from the first congestion management will be described.

[0209] For example, the UE may identify a congestion management associated with the same DNN as the first congestion management as the second congestion management. And / or the UE may identify a congestion management associated with the same S-NSSAI as the S-NSSAI associated with the first congestion management as the second congestion management. In addition, the identification of multiple congestion managements to be stopped may be configured to be performed only when the first congestion management and / or the second congestion management are a specific type of congestion management.

[0210] Specifically, when the first congestion management is any one of the first congestion management to the fourth congestion management, the UE may identify the second congestion management. And / or, when identifying the second congestion management, when the congestion management to be searched is any one of the first congestion management to the fourth congestion management, the UE may identify the second congestion management. Note that it is sufficient that the type of the first congestion management and / or the second identification information can identify multiple congestion managements is set in advance in the core network and / or the UE. Note that the specific congestion management type that is allowed to be identified does not need to be specified as one type, and multiple types may be set.

[0211] The first identification information is information for identifying that the UE belongs 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. The slice information may be identification information indicating a specific S-NSSAI. The first identification information may be information for identifying a specific NW slice in the operator A network, or information for identifying the same NW slice in common in the operator B (another operator other than the operator A). Furthermore, the first identification information may be information for identifying the first NW slice set from the HPLMN, information for identifying the first NW slice acquired from the AMF in the registration procedure, or information for identifying the first NW slice permitted from 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 may be a DNN (Data Network Name), which is 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 procedure transaction identity (PTI), which is information that identifies the transmission and reception of a series of messages of a specific session management procedure as a single group, and may further be information used to identify and / or distinguish the transmission and reception of a series of session management-related messages from each other.

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

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

[0217] Also, the NW may indicate the congestion management to the UE by transmitting at least one of the identification information from the 12th identification information to the 18th identification information together with the 11th identification information to the UE. In other words, the NW may notify the UE of the congestion management corresponding to one or a combination of the identification information from the 12th identification information to the 18th identification information. On the other hand, the UE may identify the congestion management corresponding to one or a combination of the identification information from the 12th identification information to the 18th identification information, and execute a process based on the identified congestion management. Specifically, the UE may start counting a first timer associated with the identified congestion management. 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 twelfth identification information may be a DNN that is not permitted by the network, or may be information indicating that the DNN identified by the second identification information is not permitted. Furthermore, the twelfth identification information may be the same DNN as the second identification information.

[0219] The thirteenth identification information may be a PDU Session ID and / or PTI that is not permitted by the network, or may be information indicating that the PDU Session ID and / or PTI identified by the third identification information is not permitted. Furthermore, the PDU Session ID of the thirteenth identification information may be the same PDU Session ID as the third identification information. Also, the PTI of the thirteenth 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 congestion management that the NW notifies the UE based on the rejection of the 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 configured by a combination of the 13th identification information and one or more of the 14th to 18th identification information.

[0221] The 14th identification information may be information indicating a value of a back-off timer. In other words, the back-off timer may be a value indicating a validity period of congestion management that the NW notifies the UE based on the rejection of the PDU session establishment. In other words, the UE may use the 14th identification information as a timer value in the 15th behavior executed upon receiving the 14th identification information. Furthermore, the 14th identification information may include information identifying a type of congestion management in addition to the timer value. Specifically, information identifying which congestion management is the first congestion management to the fourth congestion management may be included. For example, the information identifying the congestion management type may be a timer name identifying each congestion management, or may be a flag identifying each congestion management. Not limited to this, it may be identified by other methods, such as by a position stored in a control message.

[0222] The fifteenth identification information is information indicating one or more cause values ​​indicating the reason why this procedure is rejected. In other words, the cause value may be information indicating the congestion management applied by the network to this procedure, or may be information indicating a cause value other than congestion management that the network applies to reject this procedure.

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

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

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

[0226] Alternatively, the reason value may be information for identifying whether the congestion management that the NW notifies the UE of based on the rejection of the 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, the NW may transmit a different value as the reason value to the UE depending on whether the congestion management is the first congestion management or the second congestion management, or the third congestion management or the fourth congestion management. The UE may grasp the meaning of each value transmitted as the reason value in advance, and in the 15th behavior, identify whether the congestion management is the first congestion management or the second congestion management, or the third congestion management or the fourth congestion management, based on at least the 15th identification information.

[0227] Alternatively, the reason value may be information for identifying whether the congestion management that the NW notifies the UE of based on the rejection of the 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, the NW may transmit a different value as the reason value to the UE depending on whether the congestion management is the second congestion management or the third congestion management, or the first congestion management or the fourth congestion management. The UE may grasp the meaning of each value transmitted as the reason value in advance, and in the 15th behavior, identify whether the congestion management is the second congestion management or the third congestion management, or the first congestion management or the fourth congestion management, based on at least the 15th identification information.

[0228] Alternatively, the reason value may be information for identifying whether the congestion management that the NW notifies the UE of based on the rejection of the 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, the NW may transmit a different value as the reason value to the UE depending on whether the congestion management is the second congestion management or the fourth congestion management, or the first congestion management or the third congestion management. The UE may grasp the meaning of each value transmitted as the reason value in advance, and in the 15th behavior, identify whether the congestion management is the second congestion management or the fourth congestion management, or the first congestion management or the third congestion management, based on at least the 15th identification information.

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

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

[0231] In addition, when the third congestion management is not performed, the meaning corresponding to the third congestion management in the reason value in the above-mentioned fifteenth identification information is unnecessary, and the reason value in the fifteenth identification information may be the above description omitting the process, explanation, and meaning related to the third congestion management. In addition, when the fourth congestion management is not performed, the meaning corresponding to the fourth congestion management in the reason value in the above-mentioned fifteenth identification information is unnecessary, and the reason value in the fifteenth identification information may be the above description omitting the process, explanation, and meaning related to the fourth congestion management.

[0232] As a more detailed example, the fifteenth identification information identifying the first congestion management may be a reason value indicating insufficient resources. The fifteenth identification information identifying the second congestion management may be a reason value indicating insufficient resources for a specific slice. The fifteenth identification information identifying the third congestion management may be a reason value indicating insufficient resources for a specific slice and DNN.

[0233] In this way, the 15th identification information may be information capable of identifying a type of congestion management, and may further be information indicating which type of congestion management the back-off timer and / or back-off timer value indicated by the 14th identification information corresponds to.

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

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

[0236] For example, the Indication information may be information indicating whether or not the NW regulates which congestion management among two or more congestion managements among the first congestion management to the fourth congestion management. Therefore, the NW may transmit a value associated with the regulation management to be applied to the UE as the Indication information. The UE may grasp the meaning of each value transmitted as the Indication information in advance, and in the 15th behavior, may identify which congestion management among the first congestion management to the fourth congestion management is based on at least the 16th identification information. Here, the two or more congestion managements among the first congestion management to the fourth congestion management are congestion managements that can be identified using the Indication information, and the congestion management to be identified may be all four congestion managements, may be the first congestion management and the second congestion management, may be the third congestion management and the fourth congestion management, may be the second congestion management to the fourth congestion management, or may be any other combination.

[0237] Incidentally, the Indication information does not necessarily need to have a value corresponding to each of the congestion managements to be identified. For example, if a value of the Indication information is associated and assigned to each of the congestion managements except for the congestion management A, it is not necessary to set a value of the Indication information for the congestion management A. In this case, the NW and the UE can identify that it is the first congestion management by the fact that the Indication information is not transmitted or received. Incidentally, the congestion management A may be any one of the first to fourth congestion managements.

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

[0239] In addition, when the third congestion management is not performed, the meaning corresponding to the third congestion management in the Indication information in the above-mentioned 16th identification information is unnecessary, and the Indication information in the 16th identification information may be the above description omitting the processing, explanation, and meaning related to the third congestion management. In addition, when the fourth congestion management is not performed, the meaning corresponding to the fourth congestion management in the Indication information in the above-mentioned 16th identification information is unnecessary, and the Indication information in the 16th identification information may be the above description omitting the processing, explanation, and meaning related to the fourth congestion management.

[0240] The 17th identification information is one or more value information indicating that the procedure has been rejected. In other words, the value information may be information indicating congestion management applied by the network to the procedure. The 17th identification information may be information including at least one of identification information for identifying one or more network slices included in the 18th identification information and / or identification information included in 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 has been applied among the first congestion management to the fourth congestion management based on the 17th identification information. Furthermore, the NW may indicate the DNN and / or S-NSSAI that are the target of the congestion management to be applied to the UE based on the transmission of the PDU session establishment rejection message based on the 17th identification information. For example, if the 17th identification information is only DNN#1, it may indicate that the first congestion management targeting the DNN#1 is applied. If the 17th identification information is only S-NSSAI#1, it may indicate that the second congestion management targeting the S-NSSAI#1 is applied. If the 17th information is composed of DNN#1 and S-NSSAI#1, it may indicate that the third congestion management targeting at least one of DNN#1 and / or S-NSSAI#1 or the fourth congestion management is applied.

[0242] Furthermore, the 17th identification information does not necessarily have to be information that can identify which congestion management has been applied, from the first congestion management to the fourth congestion management, and the 17th identification information may be information that indicates the DNN and / or S-NSSAI that is the subject 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 modification (PDU session modification) is not permitted. Here, the first NW slice may be a NW slice identified 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 a 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 a 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 a registration area and / or a tracking area to which the 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 an access network to which the UE_A10 is connected. Furthermore, the 11th identification information may be identification information for identifying one or more NW slices that determine 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 the EPS. 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 activated by the UE, or may be information indicating a first timer to be stopped among the first timers activated by the UE. Specifically, the 21st identification information may be information indicating a 13th identification information stored by the UE in association with the first timer. Furthermore, the 21st identification information may be information indicating at least one of the 12th to 18th identification information stored by the UE in association with the first timer.

[0245] Furthermore, the 21st identification information may be information that changes the association between the first timer stored in the UE and information indicating at least one of the 13th to 17th identification information. For example, when a NW-initiated session management request including the 21st identification information that permits a connection to DNN#A is received while the first timer that suppresses UE-initiated session management for the combination of DNN#A and S-NSSAI#A is activated, the UE may change the association target of the activated timer to only S-NSSAI#A and recognize that the UE-initiated session management request to DNN#A is permitted. In other words, the 21st identification information may be information that indicates 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 will also be referred to as the main procedure, and the main 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, each device executes a registration procedure (S900), and UE_A10 transitions to a state registered in the network (RM-REGISTERED state). Next, each device executes a PDU session establishment procedure (S902), and UE_A10 establishes a PDU session with DN_A5, which provides a PDU connection service, via core network_B190, and the state transitions between each device to a first state (S904). Note that this PDU session is assumed to be established via the access network and UPF_A235, but is not limited thereto. That is, a UPF (UPF_C239) different from UPF_A235 may exist between UPF_A235 and the access network. In this case, this PDU session is established via the access network, UPF_C239, and UPF_A235. Next, each device in the first state may execute a session management procedure at any timing (S906). Here, the session management procedure may be a network-initiated session management procedure or a UE-initiated session management procedure.

[0248] In addition, 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. In addition, when each device exchanges various information and / or negotiates various requests in the registration procedure, the device may or may not exchange various information and / or negotiate various requests in the PDU session establishment procedure and / or the network-initiated session management procedure. In addition, when each device does not exchange various information and / or negotiate various requests in the registration procedure, the device may exchange various information and / or negotiate various requests in the PDU session establishment procedure and / or the network-initiated session management procedure. In addition, even when each device exchanges various information and / or negotiates various requests in the registration procedure, the device may exchange various information and / or negotiate various requests in the PDU session establishment procedure and / or the network-initiated session management procedure.

[0249] Furthermore, each device may execute the PDU session establishment procedure during the registration procedure, or may execute the PDU session establishment procedure after the completion of the registration procedure. Furthermore, when the PDU session establishment procedure is executed during the registration procedure, the PDU session establishment request message may be included in a registration request message and transmitted / received, the PDU session establishment acceptance message may be included in a registration acceptance message and transmitted / received, the PDU session establishment completion message may be included in a registration completion message and transmitted / received, and the PDU session establishment rejection message may be included in a registration rejection message and transmitted / received. Furthermore, 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 in which a PDU session is established between each device.

[0250] In addition, each device involved in this procedure may send and receive each control message described in this procedure, thereby sending and receiving one or more identification information contained in each control message, and store each sent and received identification information as context.

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

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

[0253] UE_A10 may start this procedure when mobility across TAs occurs. 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 a running timer expires. Furthermore, UE_A10 may start this procedure when it is necessary to update the context of each device due to disconnection or invalidation (also called deactivation) of a PDU session. Furthermore, UE_A10 may start this procedure when there is a change in capability information and / or preferences regarding the establishment of a PDU session of UE_A10. Furthermore, UE_A10 may start this procedure periodically. It should be noted that UE_A10 may execute this procedure at any time, not limited to the above, as long as a PDU session is established.

[0254] [1.3.1.1. Example of registration procedure] An example of the procedure for executing the registration procedure will be described with reference to Figure 10. In this chapter, this procedure refers to the registration procedure. Each step of this procedure will be described below.

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

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

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

[0258] In addition, when there are multiple NSIs for which UE_A10 requests registration, UE_A10 may transmit a registration request message for each NSI, or may transmit multiple registration request messages in one or more RRC messages. Also, UE_A10 may transmit the multiple registration request messages as one registration request message in one or more RRC messages.

[0259] When AMF_A240 receives a registration request message and / or a control message other than the registration request message, it performs a first condition determination. The first condition determination is for determining whether AMF_A240 accepts UE_A10's request or not. 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., if the network accepts UE_A10's request), AMF_A240 starts procedure (A) in this procedure, and if the first condition determination is false (i.e., if the network does not accept UE_A10's request), it starts procedure (B) in this procedure.

[0260] Below, the steps when the first condition determination is true, that is, each step of the procedure (A) in this procedure will be described. 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 transmits and receives SM messages with SMF_A230. In other words, the fourth condition determination may be for determining whether AMF_A240 performs a PDU session establishment procedure during this procedure. When the fourth condition determination is true (i.e., when AMF_A240 transmits and receives SM messages with SMF_A230), AMF_A240 selects SMF_A230 and transmits and receives SM messages with the selected SMF_A230, and omits them when the fourth condition determination is false (i.e., when AMF_A240 does not transmit and receive SM messages with SMF_A230) (S1006). Furthermore, if AMF_A240 receives an SM message indicating rejection from SMF_A230, it may abort procedure (A) in this procedure and start procedure (B) in this procedure.

[0261] Furthermore, AMF_A240 transmits a Registration Accept message to UE_A10 via NR node_A122 based on receipt of a registration request message from UE_A10 and / or completion of transmission and reception of an SM message with SMF_A230 (S1008). For example, if the fourth condition determination is true, AMF_A240 may transmit a registration accept message based on receipt of a registration request message from UE_A10. Also, if the fourth condition determination is false, AMF_A240 may transmit a registration accept message based on completion of transmission and reception of an SM message with SMF_A230. Here, the registration accept message may be transmitted as a response message to the registration request message. In addition, the registration acceptance message is a NAS message transmitted and received on the N1 interface, and for example, AMF_A240 may send it to NR node_A122 as a control message on the N2 interface, and NR node_A122 may receive it and include it in an RRC message and send it to UE_A10.

[0262] Furthermore, if the fourth condition determination is true, AMF_A240 may include an SM message (e.g., a PDU session establishment accept message) in the registration acceptance message and send it, or may send an SM message (e.g., a PDU session establishment accept message) together with the registration acceptance message. This transmission method may be executed when an SM message (e.g., a PDU session establishment request message) is included in the registration request message and the fourth condition determination is true. This transmission method may also be executed when an SM message (e.g., 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 the registration accept message via NR node_A122 (S1008). By receiving the registration accept message, UE_A10 recognizes the contents of various identification information contained in the registration accept message.

[0264] Next, UE_A10 transmits a Registration Complete message to AMF_A240 based on receiving the registration acceptance message (S1010). When UE_A10 receives an SM message such as a PDU session establishment acceptance message, UE_A10 may transmit an SM message such as a PDU session establishment completion message including the SM message in the registration completion message, or may indicate completion of the procedure for SM by including the SM message. Here, the registration completion message may be transmitted as a response message to the registration acceptance message. Also, the registration completion message is a NAS message transmitted and received on the N1 interface, and for example, UE_A10 may transmit the registration completion message to NR node_A122 in an RRC message, and NR node_A122 may transmit the registration completion message to AMF_A240 as a control message of the N2 interface upon receiving the message.

[0265] AMF_A240 receives the registration completion message (S1010). In addition, each device completes procedure (A) of this procedure based on the sending and receiving of the registration acceptance message and / or the registration completion message.

[0266] Next, the steps when the first condition determination is false, that is, each step of the procedure (B) in this procedure will be described. AMF_A240 starts the procedure (B) in this procedure by transmitting a registration reject message to UE_A10 via NR node_A122 (S1012). Here, the registration reject message may be transmitted 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, and for example, AMF_A240 may transmit it to NR node_A122 as a control message of the N2 interface, and NR node_A122 receiving this may include it in an RRC message and transmit it to UE_A10. Also, the registration reject message transmitted 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, procedure (B) during this procedure may be started when procedure (A) during this procedure is stopped. In procedure (A), if the fourth condition determination is true, AMF_A240 may send a registration rejection message including an SM message indicating a rejection such as a PDU session establishment rejection message, or may indicate that the procedure for SM has been rejected by including an SM message indicating a rejection. In that case, UE_A10 may further receive an SM message indicating a 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 UE_A10's request has been rejected by receiving a registration rejection message or by not receiving a registration acceptance message. Each device completes procedure (B) in this procedure based on the sending and receiving of the registration rejection message.

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

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

[0271] The first condition determination may be performed based on identification information, subscriber information, and / or operator policy included in the registration request message. For example, the first condition determination may be true if the network permits the request of UE_A10. 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 to which UE_A10 is registered and / or a device within the network supports the function requested by UE_A10, and may be false if the network does not support the function. Furthermore, the first condition determination may be true if the network is determined to be in a congested state, and may be false if the network is determined to be not in a congested state. The conditions for determining whether the first condition determination is true or false do not have to be limited to the above-mentioned conditions.

[0272] Furthermore, the fourth condition determination may be performed based on whether AMF_A240 has received an SM, or may be performed based on whether an SM message is included in the registration request message. For example, the fourth condition determination may be true if AMF_A240 has received an SM and / or if an SM message is included in the registration request message, and may be false if AMF_A240 has not received an SM and / or if an SM message is not included in the registration request message. Note that the conditions that determine whether the fourth condition determination is true or false do not have to be limited to the conditions described above.

[0273] [1.3.2. Overview of 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 will also be referred to as this procedure. This procedure is a procedure for each device to establish a PDU session. Each device may execute this procedure after completing the registration procedure, or may execute it during the registration procedure. Each device may start this procedure in the registered state, or may start this procedure at any timing after the registration procedure. Each device may also establish a PDU session based on the completion of the PDU session establishment procedure. Furthermore, each device may establish multiple PDU sessions by executing this procedure multiple times.

[0274] [1.3.2.1. Example of PDU session establishment procedure] An example of a procedure for executing a PDU session establishment procedure is described below using Figure 11. Each step of this procedure is described below. First, UE_A10 starts the PDU session establishment procedure by sending a PDU Session Establishment Request message to core network _B via access network _B (S1100). In other words, the UE sends a PDU session establishment request message to SMF_A230 in core network _B190 and starts 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 executes a third condition determination. The third condition determination is for AMF_A to determine whether to accept the request of UE_A10. In the third condition determination, AMF_A determines whether the fifth condition determination is true or false. If the third condition determination is true, core network_B starts processing #1 in the core network (S1101), and if the third condition determination is false, starts procedure (B) of this procedure. The steps when the third condition determination is false will be described later. Here, processing #1 in the core network may be SMF selection by AMF_A in core network _B190 and / or sending and receiving a PDU session establishment request message between AMF_A and SMF_A.

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

[0277] The PDU session establishment request message may be a NAS message. Also, the PDU session establishment request message may be any message that requests the establishment of a PDU session, and is not limited to this.

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

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

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

[0281] Furthermore, UE_A10 may make a request combining the above-mentioned matters by transmitting a combination of two or more of the first to fourth identification information. Note that the matters indicated by UE_A10 transmitting each identification information are not limited to these.

[0282] In addition, UE_A10 may determine which of the first to fourth identification information to include in the PDU session establishment request message based on UE_A10's capability information, and / or policies such as UE policies, and / or UE_A10's preferences, and / or an application (upper layer). In addition, 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 determination. The third condition determination is for SMF_A230 to determine whether or not to accept UE_A10's request. In the third condition determination, SMF_A230 determines whether the third condition determination is true or false. If the third condition determination is true, SMF_A230 starts procedure (A) in this procedure, and if the third condition determination is false, SMF_A230 starts procedure (B) in this procedure. The steps when the third condition determination is false will be described later.

[0284] Below, we will explain the steps when the third condition check is true, i.e., each step of procedure (A) in this procedure. SMF_A230 selects UPF_A235 as the destination for establishing the PDU session and performs the eleventh condition check.

[0285] Here, the eleventh condition determination is for each device to determine whether or not to execute the process #2 in the core network. Here, the process #2 in the core network may include the initiation and / or execution of a PDU session establishment authentication procedure by each device, and / or the transmission and reception of a session establishment request message and / or the transmission and reception of a session establishment response message between SMF_A and UPF_A in the core network_B190 (S1103). In the eleventh condition determination, SMF_A230 determines whether the eleventh condition determination is true or false. If the eleventh condition determination is true, SMF_A230 starts the PDU session establishment authentication approval procedure, and if the eleventh condition determination is false, SMF_A230 omits the PDU session establishment authentication approval procedure. The details of the PDU session establishment authentication approval procedure of the process #2 in the core network will be described later.

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

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

[0288] UPF_A235 receives the session establishment request message and creates a context for the PDU session. Furthermore, UPF_A235 sends a session establishment response message to SMF_A230 based on receiving the session establishment request message and / or creating a context for the PDU session. Furthermore, 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. Furthermore, the session establishment response message may be a response message to the session establishment request message.

[0289] Furthermore, SMF_A230 may perform address allocation of an address to be assigned to UE_A10 based on reception of a PDU session establishment request message and / or selection of UPF_A235 and / or reception of a session establishment response message. Note that SMF_A230 may perform address allocation of an address to be assigned to UE_A10 during the PDU session establishment procedure or after completion of the PDU session establishment procedure.

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

[0291] Furthermore, SMF_A230 may include the assigned address in a PDU session establishment acceptance message and send it to UE_A10 based on completion of address allocation of the address to be assigned to UE_A10, or may send it to UE_A10 after completion of the PDU session establishment procedure.

[0292] SMF_A230 sends a PDU session establishment accept message to UE_A10 via AMF_A240 based on receipt of a PDU session establishment request message, and / or selection of UPF_A235, and / or receipt of a session establishment response message, and / or completion of address allocation of an address to be assigned to UE_A10 (S1110).

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

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

[0295] Here, the PDU session ID included in the PDU session establishment accept 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 accept 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 accept message may be the same as the S-NSSAI included in the PDU session establishment request message, or it may be a different S-NSSAI. Furthermore, the S-NSSAI included in the PDU session establishment accept message may be an S-NSSAI selected by the network, or it may be a default S-NSSAI.

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

[0299] In addition, if the PDU session is a PDN connection, the PDU session establishment accept message may be a PDN connectivity accept message. Furthermore, the PDU session establishment accept message may be a NAS message transmitted and received on the N11 interface and the N1 interface. In addition, the PDU session establishment accept message is not limited to this, and may be any message indicating that the establishment of the PDU session has been accepted.

[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 contents of various identification information contained in the PDU session establishment acceptance message.

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

[0302] Specifically, UE_A10 sends a PDU session establishment completion message to AMF_A240 using the N1 interface, and AMF_A240, having received the PDU session establishment completion message, sends a PDU session establishment completion message to SMF_A230 using the N11 interface.

[0303] In addition, when the PDU session is a PDN connection, the PDU session establishment completion message may be a PDN connectivity complete message or an Activate default EPS bearer context accept message. Furthermore, the PDU session establishment completion message may be a NAS message transmitted and received on the N1 interface and the N11 interface. Furthermore, the PDU session establishment completion message may be a response message to the PDU session establishment accept message, and is not limited to this, and may be a message indicating that the PDU session establishment procedure is completed.

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

[0305] Each device completes procedure (A) in this procedure based on sending and receiving a PDU session establishment completion message, and / or sending and receiving a session change response message, and / or sending and receiving a session establishment response message, and / or sending and receiving an RA (Router Advertisement).

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

[0307] Specifically, SMF_A230 sends a PDU session establishment rejection message to AMF_A240 using the N11 interface, and AMF_A240, having received the PDU session establishment request message, sends a PDU session establishment rejection message to UE_A10 using the N1 interface.

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

[0309] Here, SMF_A230 may include one or more of the eleventh to eighteenth identification information in the PDU session establishment rejection message, or may indicate that the request of UE_A10 has been rejected by including these identification information. Note that two or more of these identification information may be configured as one or more identification information.

[0310] Furthermore, SMF_A230 may indicate that a 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 by sending 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 a PDU session establishment rejection message.

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

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

[0313] Furthermore, SMF_A230 may indicate that a request to establish a PDU session belonging to a network slice in the access network to which UE_A10 is currently connected has been rejected by sending the 18th identification information in a PDU session establishment rejection message, 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 sending the 11th identification information and / or the 14th identification information in the PDU session establishment rejection message, and may indicate whether or not the same procedure as this procedure should be performed again after completion of this procedure.

[0315] Furthermore, SMF_A230 may make a request combining the above-mentioned matters by sending a combination of two or more of the identification information items 11 to 18. Note that the matters indicated by SMF_A230 sending each identification information item do not have to be limited to these.

[0316] Furthermore, 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 network capability information, and / or policies such as operator policies, and / or network status.

[0317] Furthermore, the 12th identification information may be information indicating the same DNN as the DNN indicated by the second identification information. Furthermore, the 13th identification information may be information indicating the same PDU session ID as the PDU session ID indicated by the third identification information. Furthermore, the 18th identification information may be information transmitted when the first identification information is received and / or when the network slice indicated by the first identification information is not permitted by the network. Note that the decision by SMF_A230 of which identification information to include in the PDU session establishment rejection message is not limited to this.

[0318] As described above, core network _B190 notifies UE_A10 of the congestion management to be applied by sending a PDU session establishment rejection message. In addition, by this, core network _B190 may notify UE_A10 of the congestion management to be applied, and / or the congestion management to be performed to UE_A10, and / or information identifying the type of congestion management to be applied, and / or information identifying the target of the congestion management such as DNN and / or S-NSSAI corresponding to the congestion management to be applied, and / or the value of a timer corresponding to the congestion management to be applied.

[0319] Here, each of the above-mentioned information may be information identified by one or more pieces of identification information from the eleventh identification information to the eighteenth identification information.

[0320] The PDU session establishment rejection message that UE_A10 receives from SMF_A230 may include one or more of the identification information no. 11 to no. 18.

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

[0322] A first example of the fourth process will be described below.

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

[0324] Furthermore, when UE_A10 receives the 14th identification information and the 11th identification information, the fourth process may be a process in which UE_A10 sets the value indicated by the 14th identification information to the first timer value, or a process in which UE_A10 starts the first timer to which the timer value is set. Furthermore, when UE_A10 receives the 11th identification information, the fourth process may be a process in which UE_A10 executes one or more of the first to 11th behaviors.

[0325] Furthermore, when UE_A10 receives the 18th identification information and the 11th identification information, the fourth process may be a process in which UE_A10 executes the 12th behavior based on information identifying the NW slice included in the 18th identification information and a network slice association rule included in the 18th identification information or a network slice association rule that UE_A10 holds and sets in advance.

[0326] Furthermore, when UE_A10 receives multiple 14th identification information and 11th identification information, the fourth processing may be a processing in which UE_A10 executes a 13th behavior based on multiple first timers included in each 14th identification information and a priority management rule of the back-off timer held by UE_A10.

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

[0328] Here, the twelfth to fifteenth behaviors may be congestion management that is executed under the initiative of UE_A10 based on rules and / or policies within UE_A10. Specifically, for example, UE_A10 may be configured to include, in an internal memory and / or control unit of UE_A10, a policy (UE policy) and / or rules, a policy and / or rule management function, a policy enforcer that operates 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 that are established or attempted to be established based on requests from each application, and congestion management initiated by UE_A10 may be realized by executing any of the twelfth to fifteenth behaviors as a fourth process based on these. Here, the policy and / or rule may include one or more of a network slice association rule, and / or a back-off timer priority management rule, and / or a Network Slice Selection Policy (NSSP), which may be pre-set in the UE_A10 or may be received from the network. Here, the policy enforcer may be an NSSP enforcer. Here, the application may be an application layer protocol, and may establish or attempt to establish a PDU session based on a request from the application layer protocol. Here, the session management instance may be a software element that is dynamically generated on a PDU session basis. Here, as an internal process of the UE_A10, the S-NSSAI may be grouped, or a process based on the grouping of the S-NSSAI may be executed. Note that the internal configuration and process of the UE_A10 are not limited to these, and each element may be realized in software, or may be executed as a software process within the 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 UE_A10's switching to EPS may be based on a handover procedure or may be a RAT switching initiated by UE_A10. Furthermore, when UE_A10 receives the 18th identification information including the DCN ID, UE_A10 may execute switching to EPS during the fourth process or after the completion of the fourth process.

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

[0331] Furthermore, 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 matter 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 a higher layer and / or a lower layer.

[0334] Furthermore, in the fourth process, a process of identifying application of congestion management based on one or more of the eleventh identification information to the eighteenth identification information may be executed.

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

[0336] Furthermore, in the fourth process, a value to be set in a first timer indicated by a fourteenth identification information associated with the congestion management to be applied may be identified and set based on one or more of the eleventh to eighteenth identification information, and the first timer may start counting. 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 to seventh behaviors may be executed upon start or completion of any of the above-mentioned processes.

[0338] Furthermore, in the fourth process, one or more of the ninth to fifteenth behaviors may be executed upon start or completion of any of the above-mentioned processes.

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

[0340] Although the fourth process has been described above using the first and second examples, the fourth process is not limited to these examples. For example, the fourth process may be a combination of some of the detailed processes described in the first example and some of the detailed processes described in the second example.

[0341] Further, UE_A10 may recognize that UE_A10's request has been rejected by receiving a PDU session establishment rejection message or by not receiving a PDU session establishment accept message. Each device completes procedure (B) in this procedure based on the sending and receiving 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. Each device may transition to a state in which a 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, transition to a state in which a PDU session is not established, or transition to the first state.

[0343] 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, UE_A10 may perform a fourth process based on the completion of this procedure, or may transition to the first state after the completion of the fourth process.

[0344] Furthermore, the third condition determination may be performed based on identification information, subscriber information, and / or operator policy included in the PDU session establishment request message. 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 to which UE_A10 is connected and / or an apparatus within the network supports the function requested by UE_A10, and may be false if the network does not support the function. Furthermore, the third condition determination may be true if the network is determined to be in a congested state, and may be false if the network is determined to be not in a congested state. Note that the conditions for determining the truth or falsity of the third condition determination may not be limited to the above-mentioned conditions.

[0345] The second condition determination may be performed 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 a session on the N4 interface for the PDU session is established, and may be false if the session is not established. Note that the conditions for determining whether the second condition determination is true or false are not limited to the above-mentioned conditions.

[0346] Also, the eleventh condition determination may be performed based on the identification information, and / or subscriber information, and / or operator policy included in the PDU session establishment request message. For example, the eleventh condition determination may be true if the network permits authentication and / or authorization by DN_A5 to be performed during this procedure. Also, the eleventh condition determination may be false if the network does not permit authentication and / or authorization by DN_A5 to be performed during this procedure. Furthermore, the eleventh condition determination may be true if the network to which UE_A10 is connected and / or a device in the network supports performing authentication and / or authorization by DN_A5 during this procedure, and may be false if it does not support it. Furthermore, the eleventh condition determination may be true if the 61st identification information is received, and may be false if it is not received. In other words, the eleventh condition determination may be true if information such as SM PDU DN Request Container and / or a container including multiple pieces of information is received, and may be false if it is not received. The conditions for determining whether the eleventh condition determination is true or false do not have to be limited to the above-mentioned conditions.

[0347] By sending and receiving the PDU session establishment rejection message in the above procedure, the core network _B190 notifies the UE_A10 of the congestion management to be applied, and the UE_A10 can apply the congestion management instructed by the core network _B190. The core network B190 and the UE_A10 may apply multiple congestion managements by performing the procedures and processing described in this procedure multiple times. Each congestion management applied may be a different congestion management type, and / or congestion management corresponding to a different DNN, and / or congestion management corresponding to a different S-NNSAI, and / or congestion management with a different combination of DNN and S-NSSAI.

[0348] [1.3.3. Overview of network-initiated session management procedures] Next, an overview of the network-initiated session management procedure will be described. Hereinafter, the network-initiated session management procedure will also be referred to as this procedure. This procedure is a procedure for session management that is initiated by the network for an established PDU session. This procedure may be executed at any time after the above-mentioned registration procedure and / or PDU session establishment procedure is completed and each device transitions to the first state. Furthermore, each device may send 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] UE_A10 may also stop applying congestion management identified based on the control information transmitted and received by this procedure. In other words, core network _B190 can initiate this procedure and further transmit control messages and control information of this procedure to UE_A10, thereby informing UE_A10 to stop applying congestion management identifiable using this control information.

[0350] This procedure may be a network-initiated PDU session modification procedure and / or a network-initiated PDU session release procedure, or may execute a network-initiated session management procedure, including but not limited to these. Each device may transmit and receive a PDU session modification message in the network-initiated PDU session modification procedure, and may transmit and receive a PDU session release message in the network-initiated PDU session release procedure.

[0351] [1.3.3.1. First example of network-initiated session management procedure] An example of a network-initiated session management procedure will be described with reference to Figure 12. In this chapter, this procedure refers to the network-initiated session management procedure. Each step of this procedure will be described below.

[0352] As described above, based on the completion of the registration procedure and / or the PDU session establishment procedure, UE_A10, which has transitioned to the first state (S1200), and each device in core network _B190 initiates a network-initiated session management procedure at any timing. Here, the device in core network _B190 that initiates 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 a 21st identification information in the network-initiated session management request message, or may indicate the request of core network _B190 by including this identification information. Furthermore, the device in core network _B190 may include a PDU session ID in the network-initiated session management request message, or may include a PDU session ID to request a change to be made to the PDU session identified by the PDU session ID.

[0354] In addition, the PDU session ID included in the PDU session change request message may be the PDU session ID of the established PDU session. Furthermore, if 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, which has received the network-initiated session management request message, transmits a network-initiated session management completion message (S1204). Furthermore, UE_A may execute a fifth process (S1206) based on the 21st identification information received from Core Network_B190, and complete this procedure. UE_A10 may also perform the fifth process based on the completion of this procedure.

[0356] Here, UE_A10 may include a 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 matters indicated by core network _B190, or may be a process in which UE_A10 recognizes a request from core network _B190. Furthermore, the fifth process may be a process in which UE_A10 stores the received identification information as context, or may be a process in which UE_A10 forwards the received identification information to a higher layer and / or a lower layer.

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

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

[0361] Furthermore, when UE_A10 receives the 21st identification information, the 5th process may be the 16th behavior. Specifically, for example, the 5th process may be a process of stopping one or more timers that are being executed based on the above-mentioned 4th process.

[0362] In other words, UE_A10, having received the 21st identification information, identifies the congestion management to be stopped or changed as instructed by the network by executing the 17th behavior, and then stops or changes 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, UE_A10 may perform a 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 sending and receiving a network-initiated session management request message, core network _B190 can instruct UE_A10 to stop or change the congestion management that UE_A10 has already applied. Furthermore, UE_A10 can stop or change the congestion management that UE_A10 has applied based on the network-initiated session management request message. Here, if UE_A10 applies one or more congestion managements, the congestion management to be stopped or changed may be identified based on receiving identification information included in the network-initiated session management request message from core network _B190. In addition, each congestion management applied may be a different congestion management type, and / or congestion management corresponding to a different DNN, and / or congestion management corresponding to a different S-NNSAI, and / or congestion management with a different combination of DNN and S-NSSAI.

[0365] Further, each device completes the first network-initiated session management procedure based on completion of the above-mentioned processing and / or sending and receiving a network-initiated session management request message and / or a network-initiated session management completion message.

[0366] Furthermore, UE_A10 may perform UE processing related to the execution of a back-off timer, which will be described later, based on the completion of the first network-initiated session management procedure. In other words, UE_A10 may perform UE processing related to the execution of a back-off timer, which will be described later, 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. Second example of network-initiated session management procedure] In the first network-initiated session management procedure example described in Chapter 1.3.3.1, an example was described in which congestion management is stopped during the procedure regardless of which of the congestion management types, congestion management 1 to 4, is applied to UE_A10.

[0368] Without being limited thereto, the procedure described in the first network-initiated session management procedure example described in Chapter 1.3.3.1 may be a procedure executed in response to congestion management, for example, a procedure executed for congestion management classified into a first congestion management, a third congestion management, and a fourth congestion management among one or more congestion managements applied by UE_A10.

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

[0370] If UE_10 receives a network-initiated session management request message for the second congestion management while the back-off timer associated with the second congestion management is counting, UE_A10 may respond to core network_B190 without stopping the back-off timer associated with the second congestion management.

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

[0372] In this way, for the second congestion management, upon receiving a network-initiated session management request message, UE_A10 may continue congestion management while transmitting a response message to the network-initiated session management request message to core network_B190. Therefore, the transmission of the UE-initiated session management request message regulated by the second congestion management may continue to be inhibited.

[0373] Here, as mentioned above, the network-initiated session management request message in this procedure may be a PDU SESSION MODIFICATION COMMAND message in a network-initiated PDU session modification procedure, or a 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, which 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 modification command message in this procedure may be a PDU session modification 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). Furthermore, if the network-initiated session management request message is a PDU session modification command and / or a PDU session release message, UE_A10 and core network_B190 may be configured to perform the above-mentioned processing as well as more detailed processing described below.

[0376] Furthermore, as described above, the network-initiated session management completion message in this procedure may include a PDU session ID, which 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 request (Reactivation Required), the core network_B190 may execute the following process. Note that the information indicating a reactivation request (Reactivation Required) is information indicating a request for activation, and a specific example of the information may be 5G session management cause value #39 (5GSM Cause #39).

[0378] Hereinafter, a first example of processing and procedures when information indicating a reactivation request is received will be described.

[0379] When UE_A10 receives a network-initiated session management request message including information indicating a reactivation request (Reactivation Required), UE_A10 does not immediately initiate the UE-initiated PDU session establishment procedure again after the completion of the network-initiated session management procedure, but waits for congestion management to be released before initiating the UE-initiated PDU session establishment procedure again. Here, this UE-initiated PDU session establishment procedure may be a UE-initiated PDU session establishment procedure for the PDU session type, SSC mode, DNN, and S-NSSAI provided in the UE-initiated PDU establishment procedure when establishing the PDU session to be changed or released.

[0380] Note that waiting for the release of the congestion management may be executed after a timer associated with the second congestion management expires. In other words, it may be executed after the timer associated with the second congestion management has finished counting and / or after the timer value associated with the second congestion management becomes zero.

[0381] Further, UE_A10 may include the following supplementary information in the network-initiated session management complete message:

[0382] The supplemental information may be information indicating that a timer is waiting to expire and / or information indicating a remaining timer value. Here, the timer may be a timer associated with the second congestion management. Also, waiting for the timer to expire may be executed after the timer expires. In other words, it may be executed after the timer associated with the second congestion management has finished counting and / or after the timer value associated with the second congestion management has become zero.

[0383] In addition, the core network B_190 may receive a network-initiated session management completion message including supplemental information, recognize the value of the remaining timer, and recognize that the UE-initiated PDU session establishment procedure will be initiated after the time indicated by the remaining timer has elapsed.

[0384] Here, the remaining timer recognized by core network _B190 may be a value indicated by the received supplementary information, or it may be a value taking into account the offset between the transmission time of UE_A10 of the network-initiated session management completion message and the reception time of core network _B190 relative to the value indicated by the received supplementary information.

[0385] In addition, in addition to the first processing and procedure example when information indicating a reactivation request is received, a second processing and procedure example when information indicating a reactivation request is received may be executed as follows.

[0386] As described above, for the second congestion management, upon receiving a network-initiated session management request message, UE_A10 may continue congestion management while transmitting a response message to the network-initiated session management request message to core network_B190. Thus, while the transmission of the UE-initiated session management request message regulated by the second congestion management continues to be inhibited, UE_A10 and / or core network_B190 may be configured to be permitted only to again initiate a UE-initiated PDU session establishment procedure.

[0387] In other words, when UE_A10 receives a network-initiated session management request message including information indicating a reactivation request (Reactivation Required), it again initiates a UE-initiated PDU session establishment procedure after the completion of the network-initiated session management procedure. Here, this UE-initiated PDU session establishment procedure may be a UE-initiated PDU session establishment procedure for the PDU session type, SSC mode, DNN, and S-NSSAI provided in the UE-initiated PDU establishment procedure when establishing the PDU session to be changed or released.

[0388] In addition, while the application of congestion management continues, UE_A10 and core network B190 may execute and complete procedures permitted as exceptions, but UE_A10 may be inhibited from initiating other UE-initiated session management procedures that are inhibited by the second congestion management.

[0389] In addition, in addition to the first and second processing and procedure examples when information indicating a reactivation request is received, a third processing and procedure example may be executed when information indicating a reactivation request is received as follows.

[0390] As described above, for the second congestion management, upon receiving a network-initiated session management request message, UE_A10 transmits a response message to the network-initiated session management request message to core network_B190. Furthermore, when UE_A10 receives a network-initiated session management request message including information indicating a reactivation request (Reactivation Required), UE_A10 may stop applying the second congestion management.

[0391] In other words, UE_A10 may continue the congestion management if the network-initiated session management request message does not include information indicating a reactivation request (Reactivation Required). In this case, the transmission of the UE-initiated session management request message regulated by the second congestion management may continue to be suppressed.

[0392] Therefore, when UE_A10 receives a network-initiated session management request message including information indicating a reactivation request (Reactivation Required), it again initiates a UE-initiated PDU session establishment procedure after completing the network-initiated session management procedure. Here, this UE-initiated PDU session establishment procedure may be a UE-initiated PDU session establishment procedure for the PDU session type, SSC mode, DNN and S-NSSAI provided in the UE-initiated PDU establishment procedure when establishing the PDU session to be changed or released.

[0393] In addition, not limited to the first, second, and third processing and procedure examples when information indicating a reactivation request is received, the information indicating a reactivation request may be configured not to be transmitted by core network _B190 as follows.

[0394] More specifically, the core network _B190 may be configured to suppress the inclusion of information indicating a reactivation request (Reactivation Required) when sending a network-initiated session management request message to a UE_A10 to which congestion management is applied.

[0395] Alternatively, the core network _B190 may be configured to suppress the inclusion of information indicating a reactivation request (Reactivation Required) when sending a network-initiated session management request message to a UE_A10 to which the second congestion management is applied.

[0396] The above describes the processing and procedures of UE_A10 and core network B190, but more specifically, the processing of core network _B190 described in this chapter may be processing executed by control devices such as SMF_A230 and / or AMF_A240, which are devices within core network _B190. Therefore, core network B190 sending and receiving a control message may mean that control devices such as SMF_A230 and / or AMF_A240, which are devices within core network _B190, send and receive a control message.

[0397] Furthermore, not limited to this chapter, canceling application of congestion management or stopping congestion management may include a process of stopping a back-off timer associated with the congestion management, and continuing application of congestion management or continuing congestion management may include continuing counting of a back-off timer associated with the congestion management.

[0398] In addition, in the first, second and third processing and procedure examples when information indicating a reactivation request described in this chapter is received, it has been described that the network-initiated session management request message and / or network-initiated session management procedure is for UE_A10 to a congested S-NSSAI#A and any DNN.

[0399] In other words, this congested S-NSSAI#A and any DNN may be an S-NSSAI#A and any DNN associated with a PDU session that is the target of the network-initiated session management request message and / or network-initiated session management procedure of this chapter.

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

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

[0402] Next, a process will be described in the case where the UE moves with a change of PLMN while congestion management is applied.

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

[0404] To repeat, the first congestion management may be a DNN-based congestion management. For example, the first congestion management may be congestion management that the NW applies to the UE_A10 based on a message rejecting the UE-initiated session management request when the NW receives a UE-initiated session management request using DNN#A from the UE_A10 and congestion is detected in the NW for a specific DNN, for example, DNN#A. In this case, in applying the first congestion management, the UE_A10 may be configured to start counting a back-off timer corresponding to the first congestion management received from the NW and not transmit a UE-initiated session management request using DNN#A until the back-off 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] For the sake of explanation, we refer to this first congestion management as “first congestion management for a particular DNN.”

[0406] In addition, in the first congestion management, even if the UE-initiated session management request does not include DNN information, the NW may select a default DNN at the initiative of the NW and set it as a congestion management target. In other words, the first congestion management may be congestion management that the NW applies to the UE_A10 based on a message rejecting the UE-initiated session management request when the NW receives a UE-initiated session management request that does not use DNN information from the UE_A10 and congestion is detected in the NW for the default DNN. In this case, in the application of the first congestion management, the UE_A10 may be configured to start counting a back-off timer corresponding to the first congestion management received from the NW and not transmit a UE-initiated session management request that does not use a DNN until the back-off timer expires. In addition, 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] For the sake of explanation, the first congestion management for the default DNN is applied based on a UE-initiated session management request that does not use DNN information, and is therefore expressed as "congestion management for No DNN" to distinguish it from the first congestion management for a specific DNN. Furthermore, a UE-initiated session management request such as a PDU session establishment request message that does not use a DNN is expressed as a UE-initiated session management request 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 a DNN.

[0408] When the UE_A10 is changing the PLMN, if the back-off timer associated with the first congestion management for a specific DNN is counting, or if the back-off timer associated with the first congestion management for a specific DNN is deactivated, the UE_A10 may be configured to be able to transmit a PDU session establishment request message using this specific DNN in the new PLMN. Therefore, based on this configuration, the UE_10 may transmit a PDU session establishment request message using this specific DNN.

[0409] Here, UE_A10 may continue counting the back-off timer until the timer expires without stopping the back-off timer. Alternatively, UE_A10 may continue to hold the deactivated back-off timer in the deactivated state.

[0410] In this manner, the first congestion management for a particular DNN may be associated with a PLMN.

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

[0412] In other words, when the UE_A10 is counting a back-off timer associated with a specific DNN and a first congestion management for the PLMN before the change, or when the back-off timer associated with the specific DNN and the first congestion management for the PLMN before the change is deactivated, and when the UE_A10 is not counting a back-off timer associated with a specific DNN and the first congestion management for the PLMN after the change, and when the back-off timer associated with a specific DNN and the first congestion management for the PLMN after the change is not deactivated, the UE_A10 may be configured to transmit a PDU session establishment request message using the specific DNN in the new PLMN. Furthermore, based on this configuration, the UE_10 may transmit a PDU session establishment request message using the specific DNN.

[0413] When the UE_A10 is changing the PLMN, if the back-off timer associated with the first congestion management for No DNN is counting, or if the back-off timer associated with the first congestion management for No DNN is deactivated, the UE_A10 may be configured to transmit a PDU session establishment request message without using a DNN in the new PLMN. Therefore, based on this configuration, the UE_10 may transmit a PDU session establishment request message using this specific DNN.

[0414] Here, UE_A10 may continue counting the back-off timer until the timer expires without stopping the back-off timer. Alternatively, UE_A10 may continue to hold the deactivated back-off 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 the UE_A10 is counting the back-off timer of the first congestion management for No DNN associated with the PLMN before the change, or when the back-off timer of the first congestion management for No DNN associated with the PLMN before the change is deactivated, the UE_A10 may be configured to transmit a PDU session establishment request message in the new PLMN without using a DNN if the UE_A10 is not counting the back-off timer of the first congestion management for No DNN associated with the PLMN after the change and the back-off timer of the first congestion management for No DNN associated with the PLMN is not deactivated. Furthermore, based on this setting, the UE_10 may transmit 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] In other words, when UE_A10 changes PLMNs, if the backoff timer of the first congestion management associated with the PLMN before the change is counting, or if the backoff timer of the first congestion management associated with the PLMN before the change is deactivated, and if the backoff timer of the first congestion management associated with the PLMN after the change is not counting 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 transmit, in the new PLMN, a PDU session establishment request message using a specific DNN and / or a PDU session establishment request message without using a DNN that was restricted by the congestion management associated with the PLMN before the change.

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

[0419] When the UE_A10 is changing the PLMN, if the back-off timer associated with the first congestion management for a specific DNN is counting, or if the back-off timer associated with the first congestion management for a specific DNN is deactivated, the UE_A10 may be configured not to transmit a PDU session establishment request message using this specific 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 DNN.

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

[0421] In this manner, a first congestion management for a particular DNN may also be applied in different PLMNs.

[0422] On the other hand, when the UE_A10 is changing the PLMN, if the back-off timer associated with the first congestion management for No DNN is counting, or if the back-off timer associated with the first congestion management for No DNN is deactivated, the UE_A10 may be configured to transmit a PDU session establishment request message without using a DNN in the new PLMN. Therefore, based on this configuration, the UE_10 may transmit a PDU session establishment request message using this specific DNN.

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

[0424] Thus, the first congestion management for No DNN may be PLMN-specific.

[0425] For example, when the first congestion management for No DNN is applied, the UE associates a back-off timer with the PLMN and the No DNN and starts counting, and when the back-off timer is zero or not deactivated, the UE does not establish a PDU session using the No DNN associated with the back-off timer in the PLMN associated with the back-off timer. Also, when the back-off timer is deactivated, the UE does not establish a PDU session using the No DNN associated with the back-off timer in the PLMN associated with the back-off timer until the terminal is powered off or the USIM is removed. Also, when the back-off timer is zero, the UE may establish a PDU session using the No DNN associated with the back-off timer in the PLMN associated with the back-off timer.

[0426] In other words, when the UE_A10 is counting the back-off timer of the first congestion management for No DNN associated with the PLMN before the change, or when the back-off timer of the first congestion management for No 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 first congestion management for No DNN associated with the PLMN after the change, and the back-off timer of the first congestion management for No DNN associated with the PLMN after the change is not deactivated, the UE_A10 may be configured to transmit a PDU session establishment request message in the new PLMN without using a DNN. Furthermore, based on this configuration, the UE_10 may transmit a PDU session establishment request message without using a DNN.

[0427] Here, as the processing associated with the above-mentioned PLMN change, whether to perform the same processing or different processing regardless of whether the first congestion management is for a specific DNN or for No DNN may be set based on information previously set in UE_A10, but may also be determined depending on whether the second PLMN after the change is an equal PLMN to the first PLMN before the change. For example, if the second PLMN after the change is not an equal PLMN to the first PLMN before the change, the same processing may be applied. Also, if the second PLMN after the change is an equal PLMN to the first PLMN before the change, a different processing may be executed.

[0428] Furthermore, UE_A10 may determine its behavior based on more detailed conditions in addition to whether the PLMN is an equal PLMN. For example, UE_A10 may be configured to perform different behaviors depending on whether the second PLMN after the change is an equal PLMN to the first PLMN before the change and the registration area is not changed in the PLMN change, and whether the second PLMN after the change is an equal PLMN to the first PLMN before the change and the registration area is changed in the PLMN change.

[0429] In addition, the behavior of UE_A10 performed in each case may be one of the behaviors at the time of PLMN change described above.

[0430] For example, a first example will be described in which 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. In the case where the UE_A10 is counting a back-off timer associated with the first congestion management for a specific DNN in such a PLMN change, or the back-off timer associated with the first congestion management for a specific DNN is deactivated, the UE_A10 may be configured not to transmit a PDU session establishment request message using this specific 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 DNN.

[0431] In addition, a second example will be described in which 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. In the case where the UE_A10 is counting the back-off timer associated with the first congestion management for No DNN in such a PLMN change, or the back-off timer associated with the first congestion management for No DNN is deactivated, the UE_A10 may be configured not to transmit a PDU session establishment request message without using a DNN 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 a DNN.

[0432] Next, a first example will be described in which the second PLMN after the change is an equal PLMN to the first PLMN before the change, and the change of the PLMN involves a change of the registration area. In the case where the UE_A10 counts the back-off timer of the first congestion management for the No DNN associated with the PLMN before the change, or the back-off timer of the first congestion management for the No DNN associated with the PLMN before the change, and further, when the UE_A10 does not count the back-off timer of the first congestion management for the No DNN associated with the PLMN after the change, and the back-off timer of the first congestion management for the No DNN associated with the PLMN after the change is not deactivated, the UE_A10 may be configured to transmit a PDU session establishment request message in the new PLMN without using a DNN. Furthermore, based on this configuration, the UE_10 may transmit a PDU session establishment request message without using a DNN.

[0433] Next, a second example will be described in which the second PLMN after the change is an equal PLMN to the first PLMN before the change, and the change of the PLMN involves a change of the registration area. In the case where the UE_A10 counts the back-off timer of the first congestion management for the specific DNN associated with the PLMN before the change, or the back-off timer of the first congestion management for the specific DNN associated with the PLMN before the change, and further, when the UE_A10 does not count the back-off timer of the first congestion management for the specific DNN associated with the PLMN after the change, and the back-off timer of the first congestion management for the specific DNN associated with the PLMN is not deactivated, the UE_A10 may be configured to transmit a PDU session establishment request message using the specific DNN in the new PLMN. Furthermore, based on this configuration, the UE_10 may transmit a PDU session establishment request message using the specific DNN.

[0434] Next, a third example will be described in which the second PLMN after the change is an equivalent PLMN to the first PLMN before the change, and the change of the PLMN involves a change of the registration area. In such a change of PLMN, UE_A10 may stop a back-off timer associated with the first congestion management for a specific DNN and / or No DNN. As a result, UE_A10 may be configured to be able to transmit a PDU session establishment request message using a specific DNN and / or a PDU session establishment request message not using a specific DNN in the new PLMN. Furthermore, based on this configuration, UE_10 may transmit a PDU session establishment request message using a specific DNN and / or a PDU session establishment request message not using a specific DNN.

[0435] In addition, whether to perform the same processing or different processing regardless of whether the first congestion management is for a specific DNN or for No DNN may be set based on information previously set in UE_A10, and may be determined depending on whether the second PLMN after the change is an equal PLMN to the first PLMN before the change, as described above. However, regardless of the first congestion management, different processing may be set to be executed for the second to fourth congestion managements. For example, if the second PLMN after the change is not an equal PLMN to the first PLMN before the change, the same processing may be applied. Also, if the second PLMN after the change is an equal PLMN to the first PLMN before the change, different processing may be executed.

[0436] Furthermore, UE_A10 may determine its behavior based on more detailed conditions in addition to whether the PLMN is an equal PLMN. For example, UE_A10 may be configured to perform different behaviors depending on whether the second PLMN after the change is an equal PLMN to the first PLMN before the change and the registration area is not changed in the PLMN change, and whether the second PLMN after the change is an equal PLMN to the first PLMN before the change and the registration area is changed in the PLMN change.

[0437] In addition, the behavior of UE_A10 performed in each case may be one of the behaviors at the time of PLMN change described above.

[0438] An example where the second congestion management is applied will now be described.

[0439] For example, a first example will be described in which 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 a back-off timer associated with the second congestion management for a specific S-NSSAI in such a PLMN change, or when the back-off timer associated with the second congestion management for a specific S-NSSAI is deactivated, the UE_A10 may be configured 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 in which the second PLMN after the change is an equal 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 back-off timer corresponding to the second congestion management for No S-NSSAI or the back-off timer corresponding to the first congestion management for No S-NSSAI is deactivated in such a PLMN change, the UE_A10 may be configured not to transmit a PDU session establishment request message without using 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 S-NSSAI.

[0441] Next, a first example will be described in which the second PLMN after the change is an equal PLMN to the first PLMN before the change, and the change of the PLMN involves a change of the registration area. In the case where the UE_A10 is counting the back-off timer of the second congestion management for the No S-NSSAI associated with the PLMN before the change, or the back-off timer of the second congestion management for the No S-NSSAI associated with the PLMN before the change, and further, when the UE_A10 is not counting the back-off timer of the second congestion management for the No S-NSSAI associated with the PLMN after the change, and the back-off timer of the second congestion management for the No S-NSSAI associated with the PLMN is not deactivated, the UE_A10 may be configured to transmit a PDU session establishment request message in the new PLMN without using the S-NSSAI. Furthermore, based on this configuration, the UE_10 may transmit a PDU session establishment request message without using the S-NSSAI.

[0442] Next, a second example will be described in which the second PLMN after the change is an equal PLMN to the first PLMN before the change, and the change of the PLMN involves a change of the registration area. In the case where the UE_A10 is counting the back-off timer of the second congestion management for the specific S-NSSAI associated with the PLMN before the change, or the back-off timer of the second congestion management for the specific S-NSSAI associated with the PLMN before the change, and further, when the UE_A10 is not counting the back-off timer of the second congestion management for the specific S-NSSAI associated with the PLMN after the change, and the back-off timer of the second congestion management for the specific S-NSSAI associated with the PLMN is not deactivated, the UE_A10 may be configured to be able to transmit a PDU session establishment request message using the specific S-NSSAI in the new PLMN. Furthermore, based on this configuration, the UE_10 may transmit a PDU session establishment request message using the specific S-NSSAI.

[0443] Next, a third example will be described in which the second PLMN after the change is an equivalent PLMN to the first PLMN before the change, and the change of the PLMN involves a change of the registration area. In such a PLMN change, UE_A10 may stop a back-off timer associated with the second congestion management for a specific S-NSSAI and / or No S-NSSAI. As a result, UE_A10 may be configured to be able to transmit a PDU session establishment request message using a specific S-NSSAI and / or a PDU session establishment request message not using a specific S-NSSAI in the new PLMN. Furthermore, based on this configuration, UE_10 may transmit a PDU session establishment request message using a specific S-NSSAI and / or a PDU session establishment request message not using a specific S-NSSAI.

[0444] An example where the third congestion management is applied will now be described.

[0445] For example, a first example will be described in which 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. In the case where the UE_A10 is counting a back-off timer associated with the third congestion management for a specific [S-NSSAI, DNN] in such a PLMN change, or the back-off timer associated with the third congestion management for a specific [S-NSSAI, DNN] is deactivated, the UE_A10 may be configured 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] A second example will be described in which the second PLMN after the change is an equal 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 back-off timer associated with the third congestion management for [No S-NSSAI, DNN] in such a PLMN change, or when the back-off timer associated with the third congestion management for [No S-NSSAI, DNN] is deactivated, the UE_A10 may be configured not to transmit a PDU session establishment request message to [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 to [No S-NSSAI, DNN].

[0447] Next, a first example will be described in which the second PLMN after the change is an equal PLMN to the first PLMN before the change, and the change of the PLMN involves a change of the registration area. In the case where the UE_A10 is counting the back-off timer of the third congestion management for [No S-NSSAI, DNN] associated with the PLMN before the change, or the back-off timer of the third congestion management for [No S-NSSAI, DNN] associated with the PLMN before the change, and further, when the back-off timer of the third congestion management for [No S-NSSAI, DNN] associated with the PLMN after the change is not counted, and the back-off timer of the third congestion management for [No S-NSSAI, DNN] associated with the PLMN after the change is not deactivated, the UE_A10 may be configured to transmit a PDU session establishment request message for [No S-NSSAI, DNN] in the new PLMN. Further, based on this setting, UE_10 may send a PDU session establishment request message for [No S-NSSAI, DNN].

[0448] Next, a second example will be described in which the second PLMN after the change is an equal PLMN to the first PLMN before the change, and the change of the PLMN involves a change of the registration area. In the case where the UE_A10 is counting the back-off timer of the third congestion management for the specific [S-NSSAI, DNN] associated with the PLMN before the change, or the back-off timer of the third congestion management for the specific [S-NSSAI, DNN] associated with the PLMN before the change, and further, the UE_A10 is not counting the back-off timer of the third congestion management for the specific [S-NSSAI, DNN] associated with the PLMN after the change, and the back-off timer of the third congestion management for the specific [S-NSSAI, DNN] associated with the PLMN before the change is not deactivated, the UE_A10 may be configured to transmit a PDU session establishment request message using the specific [S-NSSAI, DNN] in the new PLMN. Further, based on this setting, UE_10 may send a PDU session establishment request message using a specific [S-NSSAI, DNN].

[0449] Next, a third example will be described in which the second PLMN after the change is an equivalent PLMN to the first PLMN before the change, and the change of the PLMN involves a change of the registration area. In such a PLMN change, the UE_A10 may stop a back-off timer associated with the third congestion management for a specific [S-NSSAI, DNN] and / or [No S-NSSAI, DNN]. As a result, the UE_A10 may be configured to be able to transmit a PDU session establishment request message using the 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, the UE_10 may transmit a PDU session establishment request message using the specific [S-NSSAI, DNN] and / or a PDU session establishment request message for [No S-NSSAI, DNN].

[0450] In addition, the back-off timer being deactivated may mean that the back-off timer and / or the congestion management associated with the back-off timer transition to a deactivated state. In addition, when UE_A10 receives a timer value indicating deactivation, it may deactivate the back-off timer and / or the congestion management associated with the back-off timer.

[0451] Here, the back-off timer to be deactivated and / or the congestion management associated with the back-off timer may be associated with a congestion management type from 1 to 4. Which congestion management type the back-off timer to be deactivated and / or the congestion management associated with the back-off timer is associated with may be determined and recognized similarly when the back-off timer value is received.

[0452] More specifically, UE_A10 may receive 14th identification information and 15th identification information from the NW indicating to deactivate a back-off timer and / or congestion management corresponding to the back-off timer, and deactivate the back-off timer for the congestion management type indicated by the 15th identification information.

[0453] In addition, in a state where the back-off timer and / or congestion management is deactivated, application of congestion management may continue until the terminal is turned off or the USIM is removed. Furthermore, the process restricted at that time may be the same as the process restricted when the back-off timer is counting according to each congestion management type.

[0454] Further, each device completes a second network-initiated session management procedure based on completion of the above-mentioned processing and / or sending and receiving a network-initiated session management request message and / or a network-initiated session management completion message.

[0455] UE_A10 may perform UE processing related to the execution of a back-off timer, which will be 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 back-off timer, which will be described later, based on the transmission and reception of a network-initiated session management request message and / or a network-initiated session management completion message.

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

[0457] UE_A10 may also stop applying congestion management identified based on the control information transmitted and received by this procedure. In other words, core network _B190 can initiate this procedure and further transmit control messages and control information of this procedure to UE_A10, thereby informing UE_A10 to stop applying congestion management identifiable using this control information.

[0458] Furthermore, UE_A10 may start applying congestion management identified based on the control information transmitted and received by this procedure. In other words, core network_B190 can initiate this procedure and further transmit control messages and control information of this procedure to UE_A10 to notify UE_A10 to start applying congestion management identifiable using this control information.

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

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

[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. Each step of this procedure will be described below with reference to FIG. 13.

[0463] As described above, UE_A10, which has transitioned to the first state (S1300) based on the completion of the registration procedure and / or the PDU session establishment procedure, can start a UE-initiated PDU session change procedure at any timing. In other words, UE_A10 may start a UE-initiated PDU session change procedure for an established PDU session at any timing. In other words, UE_A10 may start a UE-initiated PDU session change 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 change procedure by sending a PDU session change request message to SMF_A230 (S1302). Here, UE_A10 may include a PDU session ID in the PDU session change request message, or may include the PDU session ID to request a change to be made to the PDU session identified by the PDU session ID.

[0465] In addition, 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 a back-off timer associated with a DNN is running, the PDU session ID included in the PDU session change request message may be a PDU session ID for identifying a PDU session not associated with the DNN. Furthermore, when a back-off timer associated with an S-NSSAI is running, the PDU session ID included in the PDU session change request message may be a PDU session ID for identifying a PDU session not associated with the S-NSSAI. Furthermore, when a back-off timer associated with a DNN and an S-NSSAI is running, the PDU session ID included in the PDU session change request message may be a PDU session ID for identifying a PDU session not associated with the DNN and an S-NSSAI.

[0466] Next, SMF_A230 receives the PDU session change request message sent by UE_A10. If SMF_A230 accepts UE_A10's request, it initiates a network-initiated PDU session change procedure. Conversely, if SMF_A230 rejects UE_A10's request, it sends a PDU session change rejection message to UE_A10. Below, we will explain the case where SMF_A230 rejects UE_A10's request.

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

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

[0469] Furthermore, SMF_A230 may notify UE_A10 of the congestion management to be applied by sending a PDU session change rejection message. Furthermore, this may allow core network_B190 to notify UE_A10 of the congestion management to be applied and / or to indicate to UE_A10 that congestion management is to be performed and / or to notify information identifying the type of congestion management to be applied and / or information identifying the target of the congestion management, such as DNN and / or S-NSSAI associated with the congestion management to be applied and / or the value of a timer associated with the congestion management to be applied.

[0470] Here, each of the above-mentioned information may be information identified by one or more pieces of identification information from the eleventh identification information to the eighteenth identification information.

[0471] UE_A10 receives the PDU session change rejection message. Further, each device completes the procedure based on sending and receiving the PDU session change rejection message and / or completing the network-initiated PDU session change procedure.

[0472] Here, UE_A10 may recognize that UE_A10's request has been rejected based on the receipt of the PDU session change rejection message. Furthermore, UE_A10 may perform a fourth process based on the receipt 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] Furthermore, the fourth process may be a process in which UE_A10 recognizes the matter indicated by SMF_A230. Furthermore, the fourth process may be a process in which UE_A10 stores the received identification information as context, or may be a process in which UE_A10 forwards the received identification information to a higher layer and / or a lower layer. Furthermore, the fourth process may be a process in which UE_A10 recognizes that the request for this procedure has been rejected.

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

[0476] Furthermore, when UE_A10 receives the 11th identification information and / or the 14th identification information and / or the 15th identification information, it may set the value indicated by the 14th identification information to the value of the back-off timer or may start the back-off timer with the timer value set. In other words, UE_A10 may set the value indicated by the 14th identification information to the value of the back-off timer or may start the back-off timer with the timer value set based on the reception of a PDU session change rejection message including the 11th identification information and / or the 14th identification information and / or the 15th identification information.

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

[0478] By sending and receiving the PDU session change rejection message in the above procedure, the core network _B190 notifies the UE_A10 of the congestion management to be applied, and the UE_A10 can apply the congestion management instructed by the core network _B190. The core network B190 and the UE_A10 may apply multiple congestion managements by performing the procedures and processing described in this procedure multiple times. Each congestion management applied may be a different congestion management type, and / or congestion management corresponding to a different DNN, and / or congestion management corresponding to a different S-NNSAI, and / or congestion management with a different combination of DNN and S-NSSAI.

[0479] Furthermore, each device completes the UE initiated PDU session modification procedure based on completion of the above-mentioned processing and / or sending or receiving a UE initiated PDU session modification rejection message.

[0480] UE_A10 may perform UE processing related to the execution of a back-off timer, which will be described later, based on the completion of the UE-initiated PDU session change procedure. In other words, UE_A10 may perform UE processing related to the execution of a back-off timer, which will be 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 is described below.

[0482] The UE-initiated PDU session release procedure may be a procedure similar to the PDU session modification procedure described above.

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

[0484] Furthermore, if this procedure is a UE-initiated PDU session release procedure, the behavior of SMF_A230 performed upon receipt of a PDU session release request message may be similar to the behavior of SMF_A230 performed upon receipt of the above-mentioned PDU session change request message. Furthermore, if this procedure is a UE-initiated PDU session release procedure, the behavior of UE_A10 performed upon receipt of a PDU session release rejection message may be similar to the behavior of UE_A10 performed upon receipt of the above-mentioned PDU session change rejection message.

[0485] Furthermore, if the procedure is a UE-initiated PDU session release procedure, SMF_A230 may initiate a network-initiated PDU session release procedure based on receiving 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 completion of the above-mentioned processing and / or sending or receiving a UE-initiated PDU session release rejection message.

[0487] UE_A10 may perform UE processing related to the execution of a back-off timer, which will be described later, 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 back-off timer, which will be described later, based on the reception of a PDU session release rejection message.

[0488] [1.5. Example of UE processing regarding execution of back-off timer] This chapter describes the UE process related to the execution of the back-off timer. Here, the UE process described in this chapter may be performed based on the completion of the network-initiated session management procedure and / or the UE-initiated session management procedure. In other words, the UE process described in this chapter may be performed based on the reception of a PDU session modification command message, and / or the reception of a PDU session release command message, and / or the reception of a PDU session modification rejection message, and / or the reception of a PDU session release rejection message.

[0489] The processing of UE_A10 and NW associated with the change of PLMN described above has been described for the first congestion management and / or the back-off timer for the first congestion management, but similar processing may 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 restricted or permitted may be a message according to each type.

[0490] In other words, congestion management and / or back-off timers associated with congestion management may be associated with a PLMN regardless of the type of congestion management.

[0491] Alternatively, any congestion management and / or back-off timer associated with the congestion management may be configured to be associated with the PLMN. Thus, for the first congestion management, the second congestion management, and the third congestion management, the congestion management and / or back-off timer associated with the congestion management may be configured to be associated with the PLMN. Alternatively, for the first congestion management, the second congestion management, and the third congestion management for No DNN, the congestion management and / or back-off timer associated with the congestion management may be configured to be associated with the PLMN, and the first congestion management for a particular 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 back-off timer corresponding to each congestion management may be the processing for the first congestion management associated with the PLMN described above and / or the processing related to the back-off timer corresponding to the first congestion management associated with the PLMN described above, in which the first congestion management in the description is replaced with the second to fourth types of congestion management.

[0493] In addition, the processing when each congestion management is not associated with a PLMN and / or the processing related to the back-off timer corresponding to each congestion management may be the processing for the first congestion management not associated with a PLMN described above and / or the processing related to the back-off timer corresponding to the first congestion management not associated with a PLMN described above, in which the first congestion management in the description is replaced with the second to fourth types of congestion management.

[0494] However, as mentioned above, the PDU session establishment request message whose transmission is restricted or permitted may be a message according to various types.

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

[0496] As described above, the back-off timer associated with the second congestion management may be a back-off timer for slice-based congestion management. Furthermore, the back-off timer for slice-based congestion management may be a timer that is started and / or stopped on an S-NSSAI and / or PLMN basis.

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

[0498] Furthermore, while this timer is counting, UE_A10 may configure the new PLMN to permit transmission of an SM request message that was prohibited in the previous PLMN based on specific conditions described below. Note that when it is expressed that transmission of an SM request message that was prohibited in the previous PLMN is permitted, this may mean that transmission of an SM request message using the same S-NSSAI as the S-NSSAI associated with the back-off timer is permitted.

[0499] It may also be a timer associated with no S-NSSAI and for prohibiting the transmission of an SM request message using no S-NSSAI. In other words, UE_A10 may configure this timer not to transmit an SM request message using no S-NSSAI while the timer is counting. Furthermore, UE_A10 may configure this timer to permit the transmission of an SM request message that was prohibited in the previous PLMN based on specific conditions described below while the timer is counting. Note that when it is expressed that the transmission of an SM request message that was prohibited in the previous PLMN is permitted, this may mean that the transmission of an SM request message using no S-NSSAI is permitted.

[0500] Also, the back-off timer associated with the third congestion management may be a back-off timer for congestion management for the combination of the S-NSSAI and the DNN, as described above. Furthermore, the back-off timer for congestion management for the combination of the S-NSSAI and the DNN may be a timer that is started and / or stopped on an S-NSSAI, and / or DNN, and / or PLMN basis.

[0501] Specifically, the back-off timer for congestion management for a combination of an S-NSSAI and a DNN may be a timer that is associated with a combination of a specific S-NSSA and a specific DNN and that prohibits the transmission of an SM request message using the specific S-NSSAI and the specific DNN. In other words, UE_A10 may set this timer not to transmit an SM request message using the specific S-NSSAI and the specific DNN while the timer is counting. Furthermore, UE_A10 may set this timer to be allowed to transmit an SM request message that was prohibited in the PLMN before the change based on a specific condition described later while the timer is counting. In addition, when it is expressed that the transmission of an SM request message that was prohibited in the PLMN before the change is allowed, this may mean that the transmission of an SM request message using the same S-NSSAI as the S-NSSAI associated with the back-off timer and the same DNN as the DNN associated with the back-off timer is allowed.

[0502] In addition, the back-off timer for congestion management for the combination of S-NSSAI and DNN may be a timer that is associated with a combination of no S-NSSAI and a specific DNN and prohibits the transmission of an SM request message using no S-NSSAI and a specific DNN. In other words, UE_A10 may be configured not to transmit an SM request message including no S-NSSAI and a specific DNN while this timer is counting. Furthermore, UE_A10 may be configured, while this timer is counting, to permit the transmission of an SM request message that was prohibited in the PLMN before the change, in the new PLMN, based on a specific condition described below. Note that when it is expressed that the transmission of an SM request message that was prohibited in the PLMN before the change is permitted, 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 back-off timer is permitted.

[0503] Furthermore, the back-off timer for congestion management for a combination of S-NSSAI and DNN may be a timer that is associated with a combination of a specific S-NSSAI and no DNN, and that prohibits the transmission of an SM request message using a specific S-NSSAI and no DNN. In other words, UE_A10 may be configured not to transmit an SM request message using a specific S-NSSAI and no DNN while this timer is counting. Furthermore, UE_A10 may be configured, while this timer is counting, to permit the transmission of an SM request message that was prohibited in the PLMN before the change, in the new PLMN, based on a specific condition described below. Note that when it is expressed that the transmission of an SM request message that was prohibited in the PLMN before the change is permitted, this may mean that the transmission of an SM request message using the same S-NSSAI as the S-NSSAI associated with the back-off timer and no DNN is permitted.

[0504] Furthermore, the back-off timer for congestion management for the combination of S-NSSAI and DNN may be a timer that corresponds to the combination of no S-NSSAI and no DNN, and prohibits the transmission of an SM request message using no S-NSSAI and no DNN. In other words, UE_A10 may configure this timer not to transmit an SM request message using no S-NSSAI and no DNN while the timer is counting. Furthermore, UE_A10 may configure this timer to permit the transmission of an SM request message that was prohibited in the PLMN before the change based on a specific condition described below while the timer is counting. Note that when it is expressed that the transmission of an SM request message that was prohibited in the PLMN before the change is permitted, this may mean that the transmission of an SM request message using no S-NSSAI and no DNN is permitted.

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

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

[0507] Furthermore, UE_A10 may start a back-off timer associated with the second congestion management based on receiving the fifteenth identification information. Furthermore, UE_A10 may set the fourteenth identification information to the timer value of the back-off timer based on receiving the fourteenth identification information. Furthermore, UE_A10 may associate the S-NSSAI with the back-off timer when the S-NSSAI is provided in the PDU session establishment procedure. Conversely, UE_A10 may associate no S-NSSAI with the back-off timer when the S-NSSAI is not provided in the PDU session establishment procedure.

[0508] Furthermore, UE_A10 may perform the second congestion management using the S-NSSAI provided by UE_A10 to the network and the S-NSSAI provided by UE_A10 from the network 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 and the S-NSSAI provided by UE_A10 from the network with a back-off timer corresponding to the second congestion management based on the reception of the 14th identification information and / or the 15th identification information. In yet another word, the back-off timer corresponding to the second congestion management may be associated with the S-NSSAI provided by UE_A10 to the network and the S-NSSAI provided by UE_A10 from the network.

[0509] Here, the 15th identity may be a 5GSM (Session Management) cause value of 69. Furthermore, the 15th identity may be a cause value indicating that the requested service cannot be provided due to insufficient resources for a particular slice.

[0510] Furthermore, if UE_A10 does not provide an S-NSSAI in the PDU session establishment procedure, it may associate the back-off timer with no S-NSSAI and an S-NSSAI associated with the PDU session. Further, if UE_A10 does not provide an S-NSSAI in the PDU session establishment procedure, it may associate the back-off timer with no S-NSSAI and an S-NSSAI transmitted and received within a PDU session establishment accept message.

[0511] Furthermore, in the PDU session establishment procedure, if an S-NSSAI is not provided by UE_A10 together with a PDU session establishment request message, the back-off timer may be associated with no S-NSSAI and an S-NSSAI associated with the PDU session. In other words, in the PDU session establishment procedure, if an S-NSSAI is not provided by UE_A10 together with a PDU session establishment request message, the S-NSSAI associated with the back-off timer may be no S-NSSAI and an S-NSSAI associated with the PDU session. In yet another word, in the PDU session establishment procedure, if an S-NSSAI is not provided by UE_A10 together with a PDU session establishment request message, UE_A10 may associate the back-off timer with no S-NSSAI and an S-NSSAI associated with the PDU session.

[0512] Furthermore, in the PDU session establishment procedure, if an S-NSSAI is not provided by UE_A10 together with a PDU session establishment request message, the back-off timer may be associated with no S-NSSAI and the S-NSSAI included in the PDU session establishment accept message and transmitted / received. In other words, in the PDU session establishment procedure, if an S-NSSAI is not provided by UE_A10 together with a PDU session establishment request message, the S-NSSAI associated with the back-off timer may be no S-NSSAI and the S-NSSAI included in the PDU session establishment accept message and transmitted / received. In yet another way, in the PDU session establishment procedure, if an S-NSSAI is not provided by UE_A10 together with a PDU session establishment request message, UE_A10 may associate the back-off timer with no S-NSSAI and the S-NSSAI included in the PDU session establishment accept message and transmitted / received.

[0513] Furthermore, in the PDU session establishment procedure, if no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, the back-off 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 no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the back-off timer may be no S-NSSAI and the S-NSSAI associated with the PDU session. In yet another word, in the PDU session establishment procedure, if no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the back-off timer with no S-NSSAI and the S-NSSAI associated with the PDU session.

[0514] Furthermore, in the PDU session establishment procedure, if no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, the back-off timer may be associated with no S-NSSAI and the S-NSSAI included in the PDU session establishment accept message and transmitted / received. In other words, in the PDU session establishment procedure, if no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the back-off timer may be no S-NSSAI and the S-NSSAI included in the PDU session establishment accept message and transmitted / received. In yet another way, in the PDU session establishment procedure, if no S-NSSAI is provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the back-off timer with no S-NSSAI and the S-NSSAI included in the PDU session establishment accept message and transmitted / received.

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

[0516] Furthermore, while a back-off timer associated with no S-NSSAI and an S-NSSAI associated with a PDU session is running, UE_A10 may be prohibited from sending an SM request message using no S-NSSAI and / or from sending an SM request message using an S-NSSAI associated with a PDU session. In other words, while a back-off timer associated with no S-NSSAI and an S-NSSAI included in a PDU session establishment accept message and transmitted / received, UE_A10 may be prohibited from sending an SM request message using no S-NSSAI and / or from sending an SM request message using an S-NSSAI included in a PDU session establishment accept message and transmitted / received.

[0517] Furthermore, UE_A10 may start a back-off timer associated with the third congestion management based on the reception of the fifteenth identification information. Furthermore, UE_A10 may set the fourteenth identification information to the timer value of the back-off timer based on the reception of the fourteenth identification information. Furthermore, UE_A10 may associate the S-NSSAI and the DNN with the back-off timer when the S-NSSAI and the DNN are provided in the PDU session establishment procedure. Furthermore, UE_A10 may associate the S-NSSAI and no DNN with the back-off timer when the S-NSSAI and the DNN are provided in the PDU session establishment procedure. Furthermore, UE_A10 may associate no S-NSSAI and the DNN with the back-off timer when the S-NSSAI and the DNN are not provided in the PDU session establishment procedure. Furthermore, UE_A10 may associate no S-NSSAI and the DNN with the back-off timer when the S-NSSAI and the DNN are not provided in the PDU session establishment procedure. Furthermore, if UE_A10 does not provide S-NSSAI and DNN in the PDU session establishment procedure, it may associate no S-NSSAI and no DNN with the backoff timer.

[0518] Furthermore, UE_A10 may perform the third congestion management using the S-NSSAI provided by UE_A10 to the network, the S-NSSAI provided by UE_A10 from the network, and the DNN based on the reception of the fourteenth identification information and / or the fifteenth identification information. In other words, UE_A10 may associate the S-NSSAI provided by UE_A10 to the network, the S-NSSAI provided by UE_A10 from the network, and the DNN with a back-off timer associated with the third congestion management based on the reception of the fourteenth identification information and / or the fifteenth identification information. In yet another word, the back-off timer associated with the third congestion management may be associated with the S-NSSAI provided by UE_A10 to the network, the S-NSSAI provided by UE_A10 from the network, and the DNN. Furthermore, the DNN may be a DNN provided by UE_A10 to the network and / or a DNN provided to UE_A10 by the network.

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

[0520] Furthermore, when UE_A10 does not provide an S-NSSAI but provides a DNN in a PDU session establishment procedure, it may associate no S-NSSAI, an S-NSSAI associated with the PDU session, and the DNN with the back-off timer. Furthermore, when UE_A10 does not provide an S-NSSAI but provides a DNN in a PDU session establishment procedure, it may associate no S-NSSAI, an S-NSSAI included in a PDU session establishment acceptance message and transmitted / received, and the DNN with the back-off timer.

[0521] Furthermore, in the PDU session establishment procedure, if the UE_A10 does not provide an S-NSSAI but provides a DNN together with the PDU session establishment request message, the back-off timer may be associated with no S-NSSAI, an S-NSSAI associated with the PDU session, and the DNN. In other words, in the PDU session establishment procedure, if the UE_A10 does not provide an S-NSSAI but provides a DNN together with the PDU session establishment request message, the S-NSSAI associated with the back-off timer may be no S-NSSAI and an S-NSSAI associated with the PDU session, and the DNN associated with the back-off timer may be the DNN. In yet another way, in the PDU session establishment procedure, if the UE_A10 does not provide an S-NSSAI but provides a DNN together with the PDU session establishment request message, the UE_A10 may associate the back-off timer with no S-NSSAI, an S-NSSAI associated with the PDU session, and the DNN.

[0522] Furthermore, in a PDU session establishment procedure, if an S-NSSAI is not provided by UE_A10 together with a PDU session establishment request message but a DNN is provided, the back-off timer may be associated with no S-NSSAI, the S-NSSAI included in the PDU session establishment accept message and transmitted / received, and the DNN. In other words, in a PDU session establishment procedure, if an S-NSSAI is not provided by UE_A10 together with a PDU session establishment request message but a DNN is provided, the S-NSSAI associated with the back-off timer may be no S-NSSAI and the S-NSSAI included in the PDU session establishment accept message and transmitted / received, and the DNN associated with the back-off timer may be the DNN. In other words, in a PDU session establishment procedure, if UE_A10 provides no S-NSSAI but a DNN together with the PDU session establishment request message, UE_A10 may associate the back-off timer with no S-NSSAI and the S-NSSAI and the DNN transmitted and received included in the PDU session establishment accept message.

[0523] Furthermore, in the PDU session establishment procedure, when no S-NSSAI and DNN are provided by UE_A10 together with the PDU session establishment request message, the back-off 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 no S-NSSAI and DNN are provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the back-off timer may be no S-NSSAI and the S-NSSAI associated with the PDU session, and the DNN associated with the back-off timer may be the DNN. In yet another word, in the PDU session establishment procedure, when no S-NSSAI and DNN are provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the back-off timer with no S-NSSAI, the S-NSSAI associated with the PDU session, and the DNN.

[0524] Furthermore, in a PDU session establishment procedure, if no S-NSSAI and DNN are provided by UE_A10 together with a PDU session establishment request message, the back-off timer may be associated with no S-NSSAI, the S-NSSAI included in the PDU session establishment accept message and transmitted / received, and the DNN. In other words, in a PDU session establishment procedure, if no S-NSSAI and DNN are provided by UE_A10 together with a PDU session establishment request message, the S-NSSAI associated with the back-off timer may be no S-NSSAI and the S-NSSAI included in the PDU session establishment accept message and transmitted / received, and the DNN associated with the back-off timer may be the DNN. In other words, in a PDU session establishment procedure, if no S-NSSAI and DNN are provided by UE_A10 along with a PDU session establishment request message, UE_A10 may associate the back-off timer with no S-NSSAI and the S-NSSAI and DNN sent and received included in the PDU session establishment accept message.

[0525] Here, while a back-off timer associated with no S-NSSAI and an S-NSSAI and a DNN associated with a PDU session is running, UE_A10 may be prohibited from sending an SM request message using no S-NSSAI and the DNN, and / or from sending an SM request message using an S-NSSAI and the DNN associated with a PDU session. In other words, while a back-off timer associated with no S-NSSAI and an S-NSSAI included in a PDU session establishment accept message and transmitted / received, and a DNN included in a PDU session establishment request message and transmitted / received, UE_A10 may be prohibited from sending an SM request message using no S-NSSAI and the DNN, and / or from sending an SM request message using an S-NSSAI included in a PDU session establishment accept message and transmitted / received.

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

[0527] Furthermore, in the PDU session establishment procedure, if the S-NSSAI and DNN are not provided by UE_A10 together with the PDU session establishment request message, the back-off timer may be associated with no S-NSSAI, an S-NSSAI associated with the PDU session, and no DNN. In other words, in the PDU session establishment procedure, if the S-NSSAI and DNN are not provided by UE_A10 together with the PDU session establishment request message, the S-NSSAI associated with the back-off timer may be no S-NSSAI and an S-NSSAI associated with the PDU session, and the DNN associated with the back-off timer may be no DNN. In yet another word, in the PDU session establishment procedure, if the S-NSSAI and DNN are not provided by UE_A10 together with the PDU session establishment request message, UE_A10 may associate the back-off timer with no S-NSSAI, an S-NSSAI associated with the PDU session, and no DNN.

[0528] Furthermore, in the PDU session establishment procedure, if an S-NSSAI and a DNN are not provided by UE_A10 together with a PDU session establishment request message, the back-off timer may be associated with no S-NSSAI, an S-NSSAI included in a PDU session establishment accept message and transmitted / received, and no DNN. In other words, in the PDU session establishment procedure, if an S-NSSAI and a DNN are not provided by UE_A10 together with a PDU session establishment request message, the S-NSSAI associated with the back-off timer may be no S-NSSAI, and an S-NSSAI included in a PDU session establishment accept message and transmitted / received, and the DNN associated with the back-off timer may be no DNN. In other words, if an S-NSSAI and DNN are not provided by UE_A10 along with the PDU session establishment request message in a PDU session establishment procedure, UE_A10 may associate the back-off timer with no S-NSSAI and no DNN sent and received in the PDU session establishment accept message.

[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 back-off timer may be associated with no S-NSSAI, an 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 back-off timer may be no S-NSSAI and an S-NSSAI associated with the PDU session, and the DNN associated with the back-off timer may be no DNN. In yet another word, 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 back-off timer with no S-NSSAI, an S-NSSAI associated with the PDU session, and no DNN.

[0530] Furthermore, in a PDU session establishment procedure, if no S-NSSAI and no DNN are provided by UE_A10 together with a PDU session establishment request message, the back-off timer may be associated with no S-NSSAI and the S-NSSAI and no DNN included in the PDU session establishment accept message and transmitted / received. In other words, in a PDU session establishment procedure, if no S-NSSAI and no DNN are provided by UE_A10 together with a PDU session establishment request message, the S-NSSAI associated with the back-off timer may be no S-NSSAI and the S-NSSAI included in the PDU session establishment accept message and transmitted / received, and the DNN associated with the back-off timer may be no DNN. In other words, in a PDU session establishment procedure, if UE_A10 provides no S-NSSAI and no DNN along with the PDU session establishment request message, UE_A10 may associate the back-off timer with no S-NSSAI and the S-NSSAI and no DNN sent and received included in the PDU session establishment accept message.

[0531] Here, while a back-off timer associated with no S-NSSAI and an S-NSSAI and no DNN corresponding to a PDU session is running, UE_A10 may be prohibited from sending an SM request message using no S-NSSAI and no DNN, and / or from sending an SM request message using an S-NSSAI and no DNN corresponding to a PDU session. In other words, while a back-off timer associated with no S-NSSAI and an S-NSSAI and no DNN included in a PDU session establishment accept message and transmitted / received may be prohibited from sending an SM request message using no S-NSSAI and no DNN, and / or from sending an SM request message using an S-NSSAI and no DNN included in a PDU session establishment accept message and transmitted / received.

[0532] In addition, the 14th identification information and / or the 15th identification information may be transmitted and received in a PDU session establishment rejection message transmitted and received in a PDU session establishment procedure. Furthermore, the 14th identification information and / or the 15th identification information may be transmitted and received in a PDU session modification rejection message transmitted and received in a PDU session modification procedure. Furthermore, the 14th identification information and / or the 15th identification information may be transmitted and received in a PDU session release command message transmitted and received in a PDU session release procedure.

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

[0534] When counting one or more of the back-off timers among the two examples of the back-off timer for the second congestion management and the four examples of the back-off timer for the third congestion management described above, UE_A10 may be configured to execute any of the processing from the first processing example to the eighth processing example shown below.

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

[0536] In addition, 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 PLMNs other than the PLMN. In addition, the S-NSSAI-based congestion management may be the second congestion management or the third congestion management.

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

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

[0539] Furthermore, the twentieth identification information may be an information element indicating whether the back-off timer being counted is valid in all PLMNs, and the back-off timer may be a back-off timer used in S-NSSAI based congestion management.

[0540] In this case, the 20th identification information may include information indicating that the counted back-off timer is valid in all PLMNs, or information indicating that the counted back-off timer is valid 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.

[0541] Here, the 21st identification information may be information indicating that the counted back-off timer is valid in all PLMNs, and the 22nd identification information may be information indicating that the counted back-off timer is valid only in the current PLMN.

[0542] Furthermore, the 20th identification information may be an information element indicating whether the home PLMN is congested. Note that the home PLMN being congested may be a slice in the home PLMN being congested. Furthermore, the home PLMN being congested may be a state in which S-NSSAI-based congestion management is being performed in the home PLMN.

[0543] In this case, the 20th identity may include information indicating that the home PLMN is congested or information indicating that the home PLMN is not congested. In other words, the 20th identity may i...

Claims

1. A UE (User Equipment) comprising a transceiver unit and a control unit, The transmitting / receiving unit is Sending a Protocol Data Unit (PDU) session establishment request message to the control device; Receive a PDU session establishment acceptance message from the control device, the PDU session ID including a first mapped S-NSSAI (Single Network Slice Selection Assistance Information); Furthermore, the transmitting / receiving unit Sending a PDU session change request message to the control device; receiving a PDU session change rejection message from the control device, the PDU session ID, first information, and second information; The control unit starts a back-off timer based on receipt of the PDU session change rejection message; Furthermore, the transceiver unit receives a PDU session release message including third information from the control device; The control unit stops the back-off timer based on receipt of the third information, the first information being a reason value indicating that the requested service cannot be provided due to insufficient resources for a particular slice; the second information is information indicating a value of a back-off timer, The third information is information indicating a stop of the back-off timer activated by the UE, The back-off timer is a timer that is started and stopped on an S-NSSAI and PLMN (Public Land Mobile Network) basis, If no S-NSSAI is provided by the UE together with the PDU session establishment request message, the back-off timer is mapped to no S-NSSAI and the first mapped S-NSSAI. The UE is characterized by:

2. A communication control method for UE (User Equipment), sending a Protocol Data Unit (PDU) session establishment request message to the control device; receiving a PDU session establishment acceptance message from the control device, the PDU session ID including a first mapped S-NSSAI (Single Network Slice Selection Assistance Information); further comprising the steps of: sending a PDU session change request message to the control device; receiving a PDU session change rejection message from the control device, the PDU session ID, first information, and second information; starting a back-off timer based on receipt of the PDU session change reject message; Further, receiving a PDU session release message from the control device, the PDU session release message including third information; stopping the back-off timer based on receipt of the third information; the first information being a reason value indicating that the requested service cannot be provided due to insufficient resources for a particular slice; the second information is information indicating a value of a back-off timer, The third information is information indicating a stop of the back-off timer activated by the UE, The back-off timer is a timer that is started and stopped on an S-NSSAI and PLMN (Public Land Mobile Network) basis, If no S-NSSAI is provided by the UE along with the PDU session establishment request message, the back-off timer is mapped to no S-NSSAI and the first mappedS-NSSAI. A UE communication control method comprising:

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