JP7388844B2 - UE and communication control method - Google Patents

Description

The present invention relates to a UE and a communication control method.

The 3rd Generation Partnership Project (3GPP), which is involved in standardization activities for recent mobile communication systems, is studying SAE (System Architecture Evolution), which is the system architecture for LTE (Long Term Evolution). 3GPP is working on the specification of EPS (Evolved Packet System) as a communication system that realizes all-IP (Internet Protocol). Note that the core network that constitutes EPS is called EPC (Evolved Packet Core).

In addition, in recent years, 3GPP has been studying next-generation communication technology and system architecture for 5G (5th Generation) mobile communication systems, which is the next generation mobile communication system. 5G System) (see Non-Patent Document 1 and Non-Patent Document 2). With 5GS, we identify technical issues in connecting a wide variety of terminals to cellular networks and create specifications for solutions.

For example, in a virtual network (VN) configured on a 5G mobile communication system, a LAN that realizes private communication in a 5G VN group, which is a group consisting of multiple terminals (User Equipment; UE). Optimization and diversification of communication procedures to support 5G LAN-type services (5G LAN-type services) and optimization of system architecture in line with the optimization and diversification of communication procedures are also listed as requirements.

3GPP TS 23.501 V16.1.0; 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System Architecture for the 5G System; Stage 2 (Release 16) 3GPP TS 23.502 V16.1.1; 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Procedures for the 5G System; Stage 2 (Release 16) 3GPP TS 24.501 V16.1.0; 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Non-Access-Stratum (NAS) protocol for 5G System (5GS);Stage 3 (Release 16)

In 5GS, a LAN type service that realizes private communication in a 5G VN group, which is a group consisting of multiple UEs, in a virtual network configured on 5GS is being considered (Non-Patent Document 1 and Non-Patent Document 1). (See literature 2 and non-patent literature 3).

However, when inter-system handover occurs due to UE movement, etc., the handling of whether or not to move the PDU session for 5G VN group used for communication of 5G VN group to EPC, and the behavior at that time are unclear. It's not clear.

The present invention was made in view of the above circumstances, and its purpose is to provide a communication control method when a PDU session is for a 5G VN group during handover between systems. That's true.

The UE (User Equipment; terminal device) of the present invention includes a transmitting/receiving unit that receives a PDU session establishment acceptance message from a core network in a PDU (Protocol Data Unit) session establishment procedure, and a control unit that establishes a PDU session, The PDU session is a PDU session associated with a 5G VN (Virtual Network) group, and the PDU session establishment acceptance message contains information indicating a set of EPS (Evolved Packet System) bearer contexts for the PDU session. The UE does not move the PDU session to the EPS when the system is changed from N1 mode to S1 mode.

A communication control method for a UE (User Equipment; terminal device) according to the present invention includes, in a PDU (Protocol Data Unit) session establishment procedure, a step of receiving a PDU session establishment acceptance message from a core network, and a step of establishing a PDU session. The PDU session is a PDU session associated with a 5G VN (Virtual Network) group, and the PDU session establishment acceptance message includes a set of EPS (Evolved Packet System) bearer contexts for the PDU session. The UE does not include information indicating that the PDU session is transferred to the EPS when the system is changed from N1 mode to S1 mode.

According to the present invention, when the UE hands over from 5GS to EPS, the PDU session for 5G VN group communication established in 5GS is not transferred to EPS.

1 is a diagram schematically showing a mobile communication system. 1 is a diagram illustrating an example of the configuration of an access network in a mobile communication system. FIG. 2 is a diagram showing an example of the configuration of a core network_A in a mobile communication system. FIG. 2 is a diagram showing an example of the configuration of a core network_B in a mobile communication system. FIG. 3 is a diagram showing the device configuration of a UE. FIG. 2 is a diagram showing the device configuration of an eNB/NR node. FIG. 3 is a diagram showing the device configuration of MME/AMF. FIG. 2 is a diagram showing the device configuration of SMF/PGW/UPF. FIG. 3 is a diagram showing an initial procedure. It is a diagram showing a registration procedure. FIG. 3 is a diagram showing a PDU session establishment procedure.

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

[1. System overview]
An outline of the mobile communication system in this embodiment will be explained using FIGS. 1, 2, 3, and 4. FIG. 2 is a diagram showing details of the access network in the mobile communication system of FIG. 1. FIG. 3 is a diagram mainly showing details of the core network_A90 in the mobile communication system of FIG. 1. FIG. 4 is a diagram mainly describing details of the core network_B190 in the mobile communication system of FIG. 1. As shown in FIG. 1, the mobile communication system 1 according to the present embodiment includes a terminal device (also referred to as a user device or mobile terminal device) UE (User Equipment)_A10, an access network (AN)_A, and an access network_B. , a core network (CN)_A90, a core network_B190, a packet data network (PDN)_A6, and a data network (DN)_A5. The combination of access network_A and core network_A90 may be called EPS (Evolved Packet System; 4G mobile communication system), and the combination of access network_B, core network_B190, and UE_A10 may be called 5GS (5G System). ; 5G mobile communication system), and the configurations of 5GS and EPS are not limited to these. For simplicity, core network_A90, core network B, or a combination thereof may also be referred to as a core network, and access network_A, access network_B, or a combination thereof may also be referred to as an access network or a radio access network. DN_A5, PDN_A6, or a combination thereof may also be referred to as DN.

Here, the UE_A10 is connectable to network services 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). It may be any type of device. Further, the UE_A10 may include a UICC (Universal Integrated Circuit Card) or an eUICC (Embedded UICC). Further, the UE_A10 may be a terminal device that can be connected wirelessly, and may be an ME (Mobile Equipment), an MS (Mobile Station), a CIoT (Cellular Internet of Things) terminal (CIoT UE), or the like.

Additionally, UE_A10 can be connected to an access network and/or a core network. Moreover, UE_A10 can connect with DN_A and/or PDN_A via an access network and/or core network. UE_A10 sends and receives user data (communication )do. Furthermore, user data communication is not limited to IP (Internet Protocol) communication (IPv4 or IPv6), but may also be non-IP communication in EPS, or Ethernet (registered trademark) communication or Unstructured communication in 5GS. There may be.

Here, IP communication refers to data communication using IP, and is realized by sending and receiving IP packets to which IP headers are attached. Note that the payload part of the IP packet may include user data transmitted and received by the UE_A10. Furthermore, non-IP communication refers to data communication that does not use IP, and is realized by sending and receiving data to which no IP header is attached. For example, non-IP communication may be data communication realized by sending and receiving application data to which no IP address is assigned, or may be data communication realized by sending and receiving application data to which no IP address is assigned, or UE_A10 may be assigned another header such as a Mac header or an Ethernet (registered trademark) frame header. User data to be transmitted and received may also be transmitted and received.

Furthermore, a PDU session is connectivity established between UE_A10 and DN_A5 in order to provide a PDU connection service. More specifically, a PDU session may be the connectivity established between UE_A10 and an external gateway. Here, the external gateway may be a UPF, a PGW (Packet Data Network Gateway), or the like. Further, the PDU session may be a communication path established for transmitting and receiving user data between the UE_A10 and the core network and/or the DN, or may be a communication path for transmitting and receiving PDUs. Furthermore, the PDU session may be a session established between the UE_A 10 and the core network and/or the DN, and is a logical session consisting of transfer paths such as one or more bearers between each device in the mobile communication system 1. Any communication channel may be used. More specifically, the PDU session may be a connection established between UE_A10 and core network_B190 and/or an external gateway, or a connection established between UE_A10 and UPF. The PDU session may also be the connectivity and/or connection between UE_A10 and UPF_A235 via NR node_A122. Furthermore, a PDU session may be identified by a PDU session ID and/or an EPS bearer ID.

Note that the UE_A10 can send and receive user data using a PDU session with a device such as an application server located in the DN_A5. In other words, the PDU session can transfer user data sent and received between the UE_A10 and a device such as an application server located at the DN_A5. Furthermore, each device (UE_A10, a device in the access network, a device in the core network, and/or a device in the data network) manages one or more pieces of identification information in association with the PDU session. You can. These identification information include APN (Access Point Name), TFT (Traffic Flow Template), session type, application identification information, DN_A5 identification information, NSI (Network Slice Instance) identification information, and DCN (Dedicated Core Network). ) identification information and access network identification information, and may further include other information. Furthermore, when establishing multiple PDU sessions, each piece of identification information associated with the PDU sessions may have the same content or may have different content. Furthermore, the NSI identification information is information that identifies the NSI, and may be an NSI ID or a Slice Instance ID hereinafter.

In addition, as shown in Figure 2, access network_A and access network_B include UTRAN (Universal Terrestrial Radio Access Network)_A20, E-UTRAN (Evolved Universal Terrestrial Radio Access Network)_A80, and NG-RAN (5G- RAN)_A120. Furthermore, hereinafter, UTRAN_A20 and/or E-UTRAN_A80 and/or NG-RAN_A120 will be referred to as 3GPP access or 3GPP access network, and wireless LAN access network or non-3GPP AN will be referred to as non-3GPP access or non-3GPP access network. Sometimes referred to as Each radio access network includes devices to which the UE_A10 actually connects (eg, base station devices and access points).

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

In addition, NG-RAN_A120 is a 5G access network, which may be the (R)AN shown in Figure 4, and includes one or more NR node (New Radio Access Technology node)_A122 and/or ng-eNB. configured. Note that NR node_A122 is a radio base station to which UE_A10 connects via 5G radio access, and is also referred to as gNB. In addition, ng-eNB may be an eNB (E-UTRA) that constitutes a 5G access network, and may be connected to core network_B190 via NR node_A, or directly connected to core network_B190. You can leave it there. Furthermore, when there are multiple NR nodes_A 122 and/or ng-eNBs in NG-RAN_A 120, each NR node_A 122 and/or ng-eNB may be connected to each other.

Note that NG-RAN_A120 may be an access network configured with E-UTRA and/or 5G Radio Access. In other words, NG-RAN_A120 may include eNB_A45, NR node_A122, or both. In this case, eNB_A45 and NR node_A122 may be similar devices. Therefore, NR node_A122 can be replaced with eNB_A45.

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

Note that in this specification, when the UE_A10 is connected to each radio access network, it means that it is connected to a base station device, access point, etc. included in each radio access network, and data, signals, etc. to be transmitted and received are This means that the data also goes through a base station device or access point. Note that the control messages transmitted and received between the UE_A10 and the core network_B190 may be the same regardless of the type of access network. Therefore, UE_A10 and core network_B190 transmitting and receiving messages via NR node_A122 may be the same as UE_A10 and core network_B190 transmitting messages via eNB_A45.

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

Further, 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 mean connecting to a communication terminal or server device located at DN_A5. Furthermore, transmitting and receiving user data to and from DN_A5 may mean transmitting and receiving user data to and from a communication terminal and a server device located at DN_A5. Further, although DN_A5 is located outside the core network in FIG. 1, it may be located within the core network.

Furthermore, core network_A90 and/or core network_B190 may be configured as devices within one or more core networks. Here, the device in the 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. Note that devices within the core network may also be referred to as core network devices.

Furthermore, the core network refers to an IP mobile communication network operated by a mobile network operator (MNO) connected to an access network and/or DN. The core network may be a core network for a mobile communication carrier that operates and manages the mobile communication system 1, or a core network for a virtual mobile communication carrier such as an MVNO (Mobile Virtual Network Operator) or an MVNE (Mobile Virtual Network Enabler), or a virtual It may also be a core network for mobile communication service providers. Note that the core network_A90 may be an EPC (Evolved Packet Core) that constitutes an EPS (Evolved Packet System), and the core network_B190 may be a 5GC (5G Core Network) that constitutes a 5GS. Furthermore, the core network_B190 may be a core network of a system that provides 5G communication services. Conversely, EPC may be Core Network_A90, and 5GC may be Core Network_B190. Note that the core network_A90 and/or the core network_B190 are not limited to this, and may be networks for providing mobile communication services.

Next, core network_A90 will be explained. Core network_A90 includes 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). At least one of SCEF and Node) may be included. These may also be configured as NF (Network Function). NF may refer to a processing function configured within a network. Furthermore, core network_A90 can be connected to multiple radio access networks (UTRAN_A20, E-UTRAN_A80).

For simplicity, Figure 3 shows only HSS (HSS_A50), PGW (PGW_A30), SGW (SGW_A35), and MME (MME_A40) among these, but other devices and/or NF This does not mean that it is 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.

A brief explanation of each device included in core network_A90 is given below.

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

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

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

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

MME_A40 is connected to SGW_A35, the access network, HSS_A50, and SCEF, and is a control device that performs location information management including mobility management of UE_A10 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. Further, a plurality of such control devices may be arranged in the core network_A90, and for example, a position management device different from the MME_A40 may be configured. A location management device different from MME_A40 may be connected to SGW_A35, the access network, SCEF, and HSS_A50 similarly to MME_A40. Furthermore, MME_A40 may be connected to an AMF (Access and Mobility Management Function).

Further, if a plurality of MMEs are included in the core network_A90, the MMEs may be connected to each other. Thereby, the context of UE_A10 may be transmitted and received between MMEs. In this way, the MME_A40 is a management device that transmits and receives control information related to mobility management and session management to and from the UE_A10, and in other words, it may be any control device for a control plane (C-Plane; CP).

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

Furthermore, MME_A40 may be a relay device that transfers user data as a gateway between core network_A90 and an access network. Note that the user data transmitted and received by MME_A40 acting as a gateway may be small data.

Furthermore, MME_A40 may be an NF that plays a role in mobility management, such as UE_A10, or may be an NF that manages one or more NSIs. Furthermore, MME_A40 may be an NF that plays one or more of these roles. Note that the NF may be one or more devices placed within the core network_A90, and may also be referred to as a CP function (hereinafter referred to as CPF (Control Plane Function) or Control Plane Network Function) for sending control information and/or control messages. It may be a shared CP function shared between multiple network slices.

Here, NF is a processing function configured within the network. In other words, the NF may be a functional device such as MME, SGW, PGW, CPF, AMF, SMF, or UPF, or may be function or capability information such as MM (Mobility Management) or SM (Session Management). Further, the NF may be a functional device for realizing a single function or a functional device for realizing multiple functions. For example, an NF for realizing the MM function and an NF for realizing the SM function may exist separately, or an NF for realizing both the MM function and the SM function may exist. You can.

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, when controlling access to 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.

Furthermore, the HSS_A50 and the 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.

AAA is connected to PGW30, HSS_A50, PCRF, and WLAN ANa70, and performs access control of UE_A10 connected via WLAN ANa70.

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

The PCRF may also be a PCF that creates and/or manages policies. More specifically, PCRF may be connected to UPF_A235.

ePDG is connected to PGW30 and WLAN ANb75, and delivers user data as a gateway between core network_A90 and WLAN ANb75.

SGSN is connected to UTRAN_A20, GERAN, and SGW_A35, and is a control device for position management between the 3G/2G access network (UTRAN/GERAN) and the LTE (4G) access network (E-UTRAN). It is. Furthermore, the SGSN has a function of selecting PGW and SGW, a function of managing the time zone of UE_A10, and a function of selecting MME_A40 at the time of handover to E-UTRAN.

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 that connects DN_A5 and/or PDN_A6 and core network_A90. Note that the SCEF may be a gateway for non-IP communication. Furthermore, the SCEF may have a function to convert between non-IP communication and IP communication. Further, a plurality of such gateways may be arranged in the core network_A90. Furthermore, a plurality of gateways may be arranged to connect the core network_A90 and a single DN_A5 and/or PDN_A6 and/or DN. Note that the SCEF may be configured outside or inside the core network.

Next, core network_B190 will be explained. The core network_B190 includes 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), N3IWF (Non-3GPP InterWorking Function) may be included. . These may also be configured as NF (Network Function). NF may refer to a processing function configured within a network.

For simplicity, only AMF (AMF_A240), SMF (SMF_A230), and UPF (UPF_A235) are shown in Figure 4, but other than these (device and/or NF (Network This does not mean that Function)) is not included. For simplicity, UE_A10 is also referred to as UE, AMF_A240 as AMF, SMF_A230 as SMF, UPF_A235 as UPF, and DN_A5 as DN.

Further, 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 the interface between the UE and the AMF, the N2 interface is the interface between the (R)AN (access network) and the AMF, and the N3 interface is the interface between the (R)AN (access network) and The N4 interface is the interface between SMF and UPF, the N6 interface is the interface between UPF and DN, and the N9 interface is the interface between UPF and UPF. , the N11 interface is the interface between AMF and SMF. Using these interfaces, each device can communicate with each other. Here, (R)AN is also referred to as NG RAN hereinafter.

A brief description of each device included in the core network_B190 will be given below.

First, AMF_A240 is connected to other AMFs, SMF (SMF_A230), access networks (ie, UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120), UDM, AUSF, and PCF. AMF_A240 is responsible for registration management, connection management, reachability management, mobility management such as UE_A10, and transfer of SM (Session Management) messages between UE and SMF. , Access Authentication, Access Authorization, Security Anchor Function (SEA), Security Context Management (SCM), N2 interface support for N3IWF, NAS signal communication with UE via N3IWF. It may take on roles such as supporting transmission and reception, authenticating UEs connected via N3IWF, managing RM states (Registration Management states), and managing CM states (Connection Management states). Furthermore, one or more AMF_A 240 may be arranged within the core network_B 190. Further, the AMF_A 240 may be an NF that manages one or more NSIs (Network Slice Instances). Further, the AMF_A 240 may be a common CP function (CCNF; Common CPNF (Control Plane Network Function)) shared among multiple NSIs.

Furthermore, the RM state includes a non-registered state (RM-DEREGISTERED state) and a registered state (RM-REGISTERED state). In the RM-DEREGISTERED state, the UE is not registered in the network, so the UE context in AMF does not have valid location information or routing information for the UE, so AMF cannot reach the UE. be. Furthermore, in the RM-REGISTERED state, the UE is registered with the network, so the UE can receive services that require registration with the network.

Further, the CM state includes a disconnected 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. Furthermore, 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, it has a NAS signaling connection established with the AMF via the N1 interface. Furthermore, in the CM-CONNECTED state, the UE may have an N2 interface connection and/or an N3 interface connection.

In addition, SMF_A230 has session management (SM) functions such as PDU sessions, IP address allocation and management functions for UEs, UPF selection and control functions, and traffic to appropriate destinations. UPF setting function for routing, function to notify that downlink data has arrived (Downlink Data Notification), AN-specific (AN It may have a function of providing SM information (for each session), a function of determining an SSC mode (Session and Service Continuity mode) for a session, a roaming function, etc. Additionally, SMF_A230 may be connected to AMF_A240, UPF_A235, UDM, and PCF.

UPF_A235 is also connected to DN_A5, SMF_A230, other UPFs, and access networks (ie, UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120). UPF_A235 is an anchor for intra-RAT mobility or inter-RAT mobility, packet routing & forwarding, UL CL (Uplink Classifier) function that supports routing of multiple traffic flows to one DN, Branching point function that supports multi-homed PDU sessions, QoS processing for user plane, uplink traffic verification, downlink packet buffering, and downlink data notification. It may also play a role such as a trigger function. Moreover, UPF_A235 may be a relay device that transfers user data as a gateway between DN_A5 and core network_B190. Note that the UPF_A 235 may be a gateway for IP communication and/or non-IP communication. Furthermore, UPF_A235 may have a function of transferring IP communication, or may have a function of converting non-IP communication and IP communication. Furthermore, the plurality of gateways may be a gateway that connects the core network_B190 and a single DN. Note that the UPF_A 235 may have connectivity with other NFs, and may be connected to each device via other NFs.

Note that a UPF_C 239 (also referred to as a branching point or uplink classifier), which is a UPF different from the UPF_A 235, may exist as a device or NF between the UPF_A 235 and the access network. If UPF_C239 exists, the PDU session between UE_A10 and DN_A5 will be established via the access network, UPF_C239, UPF_A235.

Also, AUSF is connected to UDM and AMF_A240. AUSF acts as an authentication server.

UDSF provides functionality for all NFs to store and retrieve information as unstructured data.

NEF provides a means to securely deliver the services and capabilities provided by 3GPP networks. Information received from other NFs is stored as structured data.

When the NRF receives an NF Discovery Request from an NF instance, it provides the NF with information about the discovered NF instance, information about available NF instances, and the services supported by the instance. to hold.

PCF is connected to SMF (SMF_A230), AF, and AMF_A240. Provides policy rules, etc.

UDM is connected to AMF_A240, SMF (SMF_A230), AUSF, and PCF. UDM includes UDM FE (application front end) and UDR (User Data Repository). The UDM FE processes credentials, location management, subscription management, etc. The UDR stores the data required by the UDM FE to serve and the policy profiles required by the PCF.

AF is connected to PCF. AF influences traffic routing and participates in policy control.

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

Further, the S1 mode is a UE mode in which messages can be sent and received using the S1 interface. Note that the S1 interface may include an S1-MME interface, an S1-U interface, and an X2 interface that connects the wireless base stations.

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

Note that access to the EPC via eNB that provides the E-UTRA function and access to the EPC via en-gNB that provides the NR function are defined as S1 mode, but they may be configured as separate and different modes. .

Furthermore, the N1 mode is a UE mode in which the UE can access 5GC via the 5G access network. Further, the N1 mode may be a UE mode in which messages can be sent and received using the N1 interface. Note that the N1 interface may be configured with an Xn interface that connects the N1 interface and the wireless base stations.

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

Note that access to 5GC via ng-eNB that provides the E-UTRA function and access to 5GC via gNB that provides NR function are the N1 mode, but they may be configured as separate and different modes. .

[1.2. Configuration of each device]
The configuration of each device will be explained below. In addition, some or all of the functions of each device and each part of each device described below may be operated on physical hardware, or may be logical hardware configured virtually on general-purpose hardware. It may also be something that runs on hardware.

[1.2.1.UE configuration]
First, an example of the device configuration of UE_A10 is shown in FIG. As shown in FIG. 5, the UE_A10 includes a control unit_A500, a transmitting/receiving unit_A520, and a storage unit_A540. The transmitting/receiving unit_A520 and the storage unit_A540 are connected to the control unit_A500 via a bus. Furthermore, an external antenna 410 is connected to the transmitting/receiving section_A520.

The control unit_A500 is a functional unit for controlling the entire UE_A10, and realizes various processes for the entire UE_A10 by reading and executing various information and programs stored in the storage unit_A540.

Transmission/reception 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 to connect to the access network. be. In other words, the UE_A10 can connect with base stations and/or access points in the access network via the external antenna 410 connected to the transceiver unit_A520. Specifically, the UE_A10 transmits and receives user data and/or control information to and from base stations and/or access points in the access network via the external antenna 410 connected to the transceiver unit_A520. I can do it.

The storage unit_A540 is a functional unit that stores programs, data, etc. necessary for each operation of the UE_A10, and is configured of, for example, a semiconductor memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), and the like. The storage unit_A540 stores identification information, control information, flags, parameters, rules, policies, etc. included in control messages sent and received during communication procedures to be described later.

[1.2.2. eNB/NR node]
Next, an example of the device configuration of eNB_A45 and NR node_A122 is shown in FIG. As shown in FIG. 6, the eNB_A45 and NR node_A122 are composed of a control unit_B600, a network connection unit_B620, a transmitting/receiving unit_B630, and a storage unit_B640. The network connection unit_B620, the transmission/reception unit_B630, and the storage unit_B640 are connected to the control unit_B600 via a bus. Furthermore, an external antenna 510 is connected to the transmitting/receiving section_B630.

The control unit_B600 is a functional unit for controlling the entire eNB_A45 and NR node_A122, and controls the entire eNB_A45 and NR node_A122 by reading and executing various information and programs stored in the storage unit_B640. Achieve various processing.

Network connection unit_B620 is a functional unit for connecting eNB_A45 and NR node_A122 to AMF_A240 and UPF_A235 in the core network. In other words, eNB_A45 and NR node_A122 can be connected to AMF_A240 and UPF_A235 in the core network via network connection part_B620. Specifically, eNB_A45 and NR node_A122 can send and receive user data and/or control information to and from AMF_A240 and/or UPF_A235 via network connection part_B620.

Transmission/reception unit_B630 is a functional unit for eNB_A45 and NR node_A122 to connect with UE_A10. In other words, the eNB_A45 and the NR node_A122 can transmit and receive user data and/or control information to and from the UE_A10 via the transmitting/receiving unit_B630.

The storage unit_B640 is a functional unit that stores programs, data, etc. necessary for each operation of the eNB_A45 and NR node_A122. The storage unit_B640 is composed of, for example, a semiconductor memory, an HDD, an SSD, or the like. The storage unit_B640 stores identification information, control information, flags, parameters, etc. included in control messages transmitted and received during communication procedures described later. The storage unit_B640 may store this information as a context for each UE_A10.

[1.2.3.MME/AMF configuration]
Next, an example of the device configuration of MME_A40 or AMF_A240 is shown in FIG. As shown in FIG. 7, the MME_A40 or AMF_A240 is composed of a control unit_C700, a network connection unit_C720, and a storage unit_C740. The network connection unit_C720 and the storage unit_C740 are connected to the control unit_C700 via a bus. Furthermore, the storage unit_C740 stores a context 642.

The control unit_C700 is a functional unit for controlling the entire MME_A40 or AMF_A240, and realizes various processes for the entire AMF_A240 by reading and executing various information and programs stored in the storage unit_C740. do.

The network connection part_C720 is configured to connect 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, MME_A40 or AMF_A240 may send and receive user data and/or control information to and from base stations and/or access points, UDMs, AUSFs, PCFs in the access network via network connection_C720. I can do it.

The storage unit_C740 is a functional unit that stores programs, data, etc. necessary for each operation of the MME_A40 or AMF_A240. The storage unit_C740 is configured of, for example, a semiconductor memory, an HDD, an SSD, or the like. The storage unit_C740 stores identification information, control information, flags, parameters, etc. included in control messages transmitted and received during communication procedures to be described later. The context 642 stored in the storage unit_C740 may include a context stored for each UE, a context stored for each PDU session, and a context stored for each bearer. Contexts stored for each UE 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. Further, 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. In addition, the contexts stored for each bearer include EPS Bearer ID, TI, TFT, SGW F-TEID, PGW F-TEID, MME F-TEID, eNB Address, NR node Address, WAG Address, eNB ID, NR node ID, WAG ID may be included.

Furthermore, there may be an N26 interface between the MME_A40 in the EPC and the AMF_A240 in the 5GC as an interface between the core networks. Here, the N26 interface is an optional interface for interworking between 5GS and EPS systems.

The N26 interface is an interface that enables the exchange of information regarding the mobility management status of UE_A10, etc., and the SM (Session Management) status between the UE and SMF between 5GS and EPS. It's good to be there. Furthermore, the N26 interface may be the required interface to enable seamless session continuation for inter-system change from N1 mode to S1.

[1.2.4.SMF configuration]
Next, an example of the device configuration of SMF_A230 is shown in FIG. As shown in FIG. 8, the SMF_A230 includes a control unit_D800, a network connection unit_D820, and a storage unit_D840. The network connection unit_D820 and the storage unit_D840 are connected to the control unit_D800 via a bus. Furthermore, the storage unit_D840 stores a context 742.

The control unit_D800 of SMF_A230 is a functional unit for controlling the entire SMF_A230, and realizes various processes of the entire SMF_A230 by reading and executing various information and programs stored in the storage unit_D840. do.

Further, the network connection unit_D820 of the SMF_A230 is a functional unit for connecting the SMF_A230 with the AMF_A240, UPF_A235, UDM, and PCF. In other words, the SMF_A 230 can send and receive user data and/or control information to and from the AMF_A 240, UPF_A 235, UDM, and PCF via the network connection_D 820.

Furthermore, the storage unit_D840 of the SMF_A230 is a functional unit that stores programs, data, etc. necessary for each operation of the SMF_A230. The storage unit_D840 of the SMF_A230 is configured by, for example, a semiconductor memory, an HDD, an SSD, or the like. The storage unit_D840 of the SMF_A230 stores identification information, control information, flags, parameters, etc. included in control messages transmitted and received during communication procedures described later. In addition, the context 742 stored in the storage unit_D840 of SMF_A230 includes 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. There may be a context in which The context stored for each UE may include IMSI, ME Identity, MSISDN, and RAT type. The context stored for each APN may include APN in use. Note that the context stored for each APN may be stored for each Data Network Identifier. The context stored for each PDU session may include Assigned Session Type, IP Address(es), SGW F-TEID, PGW F-TEID, and Default Bearer. The context stored for each bearer may include EPS Bearer ID, TFT, SGW F-TEID, PGW F-TEID.

[1.2.5.PGW/UPF configuration]
Next, an example of the device configuration of PGW_A30 or UPF_A235 is shown in FIG. As shown in FIG. 8, the PGW_A30 or UPF_A235 each includes a control unit_D800, a network connection unit_D820, and a storage unit_D840. The network connection unit_D820 and the storage unit_D840 are connected to the control unit_D800 via a bus. Furthermore, the storage unit_D840 stores a context 742.

The control unit_D800 of the PGW_A30 or UPF_A235 is a functional unit for controlling the entire PGW_A30 or UPF_A235, and by reading and executing various information and programs stored in the storage unit_D840, the control unit_D800 of the PGW_A30 or UPF_A235 Achieve various overall processing.

In addition, the network connection part_D820 of PGW_A30 or UPF_A235 connects PGW_A30 or UPF_A235 to DN (that is, DN_A5), SMF_A230, other UPF_A235, and access networks (that is, UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120). This is a functional section for In other words, the UPF_A235 communicates between the DN (i.e., DN_A5), the SMF_A230, other UPF_A235s, and the access networks (i.e., UTRAN_A20, E-UTRAN_A80, and NG-RAN_A120) via the network connection_D820. User data and/or control information can be sent and received.

Furthermore, the storage unit_D840 of the UPF_A235 is a functional unit that stores programs, data, etc. necessary for each operation of the UPF_A235. The storage unit_D840 of the UPF_A235 is composed of, for example, a semiconductor memory, an HDD, an SSD, or the like. The storage unit_D840 of the UPF_A235 stores identification information, control information, flags, parameters, etc. included in control messages transmitted and received during communication procedures described later. In addition, the context 742 stored in the storage unit_D840 of UPF_A235 includes 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. There may be a context in which The context stored for each UE may include IMSI, ME Identity, MSISDN, and RAT type. The context stored for each APN may include APN in use. Note that the context stored for each APN may be stored for each Data Network Identifier. The context stored for each PDU session may include Assigned Session Type, IP Address(es), SGW F-TEID, PGW F-TEID, and Default Bearer. The context stored for each bearer may include EPS Bearer ID, TFT, SGW F-TEID, PGW F-TEID.

[1.2.6. Information stored in the storage unit of each device]
Next, each piece of information stored in the storage section of each of the above devices will be explained.

IMSI (International Mobile Subscriber Identity) is permanent identification information of a subscriber (user), and is 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.

EMM State/MM State indicates the mobility management state of UE_A10 or MME_A40/CPF_A140/AMF_A240. For example, the EMM State/MM State may be an EMM-REGISTERED state (registered state) in which UE_A10 is registered with the network, and/or an EMM-DEREGISTERD state (non-registered state) in which UE_A10 is not registered in the network. Furthermore, the EMM State/MM State may 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. Note that EMM State/MM State may be information that can distinguish between a state in which UE_A10 is registered in EPC and a state in which UE_A10 is registered in NGC or 5GC.

GUTI (Globally Unique Temporary Identity) is temporary identification information of UE_A10. GUTI consists of the identification information of MME_A40/CPF_A140/AMF_A240 (GUMMEI (Globally Unique MME Identifier)) and the identification information of UE_A10 within the specific MME_A40/CPF_A140/AMF_A240 (M-TMSI (M-Temporary Mobile Subscriber Identity)). be done. ME Identity is the 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 phone number of UE_A10. The MSISDN stored in MME_A40/CPF_A140/AMF_A240 may be information indicated by the storage unit of HSS_A50. Note that GUTI may include information that identifies CPF_140.

MME F-TEID is information that identifies MME_A40/CPF_A140/AMF_A240. The MME F-TEID may include the IP address of MME_A40/CPF_A140/AMF_A240, may include the TEID (Tunnel Endpoint Identifier) of MME_A40/CPF_A140/AMF_A240, or may include both of these. Good too. Furthermore, the IP address of MME_A40/CPF_A140/AMF_A240 and the TEID of MME_A40/CPF_A140/AMF_A240 may be stored independently. Further, the MME F-TEID may be identification information for user data or identification information for control information.

SGW F-TEID is information that identifies SGW_A35. The SGW F-TEID may include the IP address of SGW_A35, the TEID of SGW_A35, or both. Furthermore, the IP address of SGW_A35 and the TEID of SGW_A35 may be stored independently. Further, the SGW F-TEID may be identification information for user data or may be identification information for control information.

PGW F-TEID is information that identifies PGW_A30/UPGW_A130/SMF_A230/UPF_A235. The PGW F-TEID may include the IP address of PGW_A30/UPGW_A130/SMF_A230/UPF_A235, the TEID of PGW_A30/UPGW_A130/SMF_A230/UPF_A235, or both. good. Further, 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. Furthermore, the PGW F-TEID may be identification information for user data or identification information for control information.

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

Further, the APN may be identification information that identifies the core network and an external network such as a DN. Furthermore, the APN can also be used as information for selecting a gateway such as PGW_A30/UPGW_A130/UPF_A235 that connects core network A_90. Note that the APN may be a DNN (Data Network Name). Therefore, APN may be expressed as DNN, or DNN may be expressed as APN.

Note that the APN may be identification information that identifies such a gateway, or may be identification information that identifies an external network such as a DN. Note that if a plurality of gateways connecting the core network and the DN are arranged, there may be a plurality of gateways that can be selected depending on the APN. Furthermore, one gateway may be selected from among these multiple gateways by another method using identification information other than APN.

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 that includes one or more pieces of information necessary for SGSN_A42 for UE_A10 having GERAN_A25 and/or UTRAN_A20 functionality. Access Restriction is registered 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.

APN in Use is the most recently used APN. APN in Use may also be a Data Network Identifier. This APN may consist of network identification information and default operator identification information. Furthermore, APN in Use may be information that identifies a DN to which a PDU session is to be established.

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

Furthermore, unless otherwise specified, the IP Address is an IP address assigned to the UE. The IP address may be an IPv4 address, an IPv6 address, an IPv6 prefix, or an interface ID. Note that when the Assigned Session Type indicates non-IP, the IP Address element does not need to be included.

The DN ID is identification information that identifies the core network_B190 and an external network such as a DN. Furthermore, the DN ID can also be used as information for selecting a gateway such as UPGW_A130 or PF_A235 to which core network_B190 is connected.

Note that the DN ID may be identification information that identifies such a gateway, or may be identification information that identifies an external network such as a DN. Note that if a plurality of gateways connecting the core network_B190 and the DN are arranged, there may be a plurality of gateways that can be selected based on the DN ID. Furthermore, one gateway may be selected from among these multiple gateways by another method using identification information other than the DN ID.

Further, the DN ID may be the same information as the APN, or may be information different from the APN. Note that if the DN ID and APN are different information, each device may manage information indicating the correspondence between the DN ID and APN, or perform a procedure to inquire about the APN using the DN ID. Alternatively, you may perform a procedure to inquire about the DN ID using APN.

SCEF ID is the IP address of SCEF_A46 used in the PDU session. Default Bearer is information acquired and/or generated when a PDU session is established, and is EPS bearer identification information for identifying a default bearer associated with a PDU session.

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

Default Bearer is EPS bearer identification information that identifies a default bearer associated with a PDU session. Note that 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 that configures a PDN connection/PDU session. Furthermore, the EPS bearer may be a default bearer or a dedicated bearer. Furthermore, the EPS bearer may be configured to include an RB established between the UE_A10 and a base station and/or access point in the access network. Furthermore, RBs and EPS bearers may be associated one-to-one. Therefore, the identification information of the RB may have a one-to-one correspondence with the identification information of the EPS bearer, or may be the same identification information. Note that the RB may be an SRB and/or a CRB, or a DRB. Further, the Default Bearer may be information that the UE_A10 and/or the SGW_A35 and/or the PGW_A30/UPGW_A130/SMF_A230/UPF_A235 obtain from the core network when establishing the PDU session. Note that the default bearer is an EPS bearer that is established first during a PDN connection/PDU session, and only one EPS bearer can be established during one PDN connection/PDU session. The default bearer may be an EPS bearer that can be used for communication of user data not associated with TFT. Additionally, a dedicated bearer is an EPS bearer that is established after a default bearer is established during a PDN connection/PDU session, and is an EPS bearer that can be established multiple times during one PDN connection/PDU session. be. A dedicated bearer is an EPS bearer that can be used to communicate user data associated with a TFT.

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 and 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.

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

An anchor or anchor point is a UFP that has a gateway function for DN and PDU sessions. A UPF serving as an anchor point may be a PDU session anchor or an anchor.

The SSC mode indicates a session and service continuity mode supported by the system and/or each device in 5GC. More specifically, it may be a mode indicating the type of service session continuation supported by the PDU session established between the UE_A10 and the anchor point. Here, the anchor point may be UPGW or UPF_A235. Note that the SSC mode may be a mode that indicates the type of service session continuation that is set for each PDU session. Furthermore, the SSC mode may include 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.

Furthermore, SSC mode 1 in this embodiment is a service session continuation mode in which the same UPF is maintained as an anchor point regardless of the access technology such as RAT (Radio Access Technology) or cell used when UE_A10 connects to the network. It is. More specifically, SSC mode 1 may be a mode that realizes service session continuation without changing the anchor point used by the established PDU session even if UE_A10's mobility occurs.

Furthermore, in SSC mode 2 in this embodiment, when a PDU session includes an anchor point associated with one SSC mode 2, the service session continuation is performed by first releasing the PDU session and then establishing the PDU session. mode. More specifically, SSC mode2 is a mode in which, when anchor point relocation occurs, a PDU session is once deleted and then a new PDU session is established.

Furthermore, SSC mode 2 is a mode in which service sessions continue to be maintained using the same UPF 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 continuation without changing the UPF used by the established PDU session as long as UE_A10 is within the UPF serving area. Furthermore, SSC mode 2 is a mode that changes the UPF used by the established PDU session to realize service session continuation when UE_A10's mobility occurs, such as leaving the UPF serving area. good.

Here, the TUPF serving area may be an area where one UPF can provide a service session continuation function, or a subset of access networks such as RATs and cells used by UE_A10 to connect to the network. It may be. Further, the access network subset may be a network composed of one or more RATs and/or cells, or may be a TA.

Furthermore, SSC mode 3 in this embodiment is a service session continuation mode that can establish a PDU session between a new anchor point and UE for the same DN without releasing the PDU session between the UE and the anchor point. be.

Additionally, SSC mode 3 initiates a new PDU session via a new UPF and/or for the same DN before disconnecting the established PDU session and/or communication path between the UE_A10 and the UPF. or a mode of service session continuation that allows the establishment of a communication channel. Furthermore, SSC mode 3 may be a service session continuation mode that allows UE_A10 to become multihoming.

And/or SSC mode 3 may be a mode in which continuation of a service session using multiple PDU sessions and/or a UPF associated with a PDU session is permitted. In other words, in the case of SSC mode 3, each device may implement service session continuation using multiple PDU sessions, or may implement service session continuation using multiple TUPFs.

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 is located where UE_A10 connects to the network. It may be the best UPF. Additionally, if multiple PDU sessions and/or the UPF used by the PDU sessions are enabled, the UE_A10 will immediately map the application and/or flow communication to the newly established PDU session. Alternatively, it may be performed based on the completion of communication.

[1.3. Explanation of initial procedures]
Next, before explaining the detailed steps of the initial procedure in this embodiment, terminology specific to this embodiment and main identification information used in each procedure will be explained in advance to avoid redundant explanation.

In this embodiment, the network refers to at least a portion of access network_A20/80, access network_B80/120, core network_A90, core network_B190, DN_A5, and PDN_A6. In addition, one or more devices included in at least a part of access network_A20/80, access network_B80/120, core network_A90, core network_B190, DN_A5, and PDN_A6 may be referred to as a network or network device. may be called. That is, the fact that the network sends and receives messages and/or executes procedures means that devices within the network (network devices) send and receive messages and/or execute procedures.

In this embodiment, a session management (SM) message (also referred to as a NAS (Non-Access-Stratum) SM message or an SM message) is a procedure for SM (also referred to as a session management procedure or an SM procedure). It may be a NAS message used in AMF_A240, or a control message sent and received between UE_A10 and SMF_A230 via AMF_A240. Furthermore, the SM message includes a PDU session establishment request message, a PDU session establishment acceptance message, a PDU session completion message, a PDU session rejection message, a PDU session change request message, a PDU session change acceptance message, a PDU session change rejection message, etc. You can. Further, the procedure for SM may include a PDU session establishment procedure, a PDU session change procedure, and the like.

Note that among the SM messages, the message sent by UE_A10 is expressed as an SM request message. Specifically, the PDU session establishment request message and the PDU session change request message are SM request messages.

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

In this embodiment, the TA list (TA list) is a list that includes one or more TAs assigned to UE_A10 by the network. Note that while the UE_A10 is moving within one or more TAs included in the TA list, it may be possible to move without executing the registration procedure. In other words, the TA list may be a group of information indicating areas to which the UE_A10 can move without executing a registration procedure.

In this embodiment, a network slice is a logical network that provides specific network capabilities and network characteristics. Hereinafter, a network slice will also be referred to as an NW slice.

The NSI (Network Slice Instance) in this embodiment is an entity of one or more network slices configured in the core network_B190. Further, the NSI in this embodiment may be configured by a virtual NF (Network Function) generated using an NST (Network Slice Template). Here, NST is a logical expression of one or more NFs (Network Functions) associated with resource requests for providing required communication services and capabilities. In other words, the NSI may be an aggregation within the core network_B190 configured by a plurality of NFs. Further, the NSI may be a logical network configured to separate user data distributed by services or the like. A network slice may include at least one NF. An NF configured in a network slice may or may not be a device shared with other network slices. The UE_A10 and/or devices within the network may be configured to have 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. Can be assigned to one or more network slices based on registration information and/or APN.

S-NSSAI in this embodiment is an abbreviation for 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 configured with only SST, or may be configured with both SST and SD. Here, SST is information indicating the expected behavior of a network slice in terms of functions and services. Further, the SD may be information that complements the SST when selecting one NSI from a plurality of NSIs indicated by the SST. S-NSSAI may be information specific to each PLMN (Public Land Mobile Network), standard information shared among PLMNs, or information specific to each carrier that differs for each PLMN. There may be.

More specifically, SST and/or SD may be standard information (Standard Value) shared among PLMNs, or may be carrier-specific information (Non Standard Value) that differs for each PLMN. You can.

The network may also store one or more S-NSSAIs in the registration information of UE_A10 as default S-NSSAIs.

NSSAI (Single Network Slice Selection Assistance information) in this embodiment 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 permitted by the network for each PLMN. Further, NSSAI may be information used to select AMF_A240.

The operator A network in this embodiment is a network operated by network operator A (operator A). Here, for example, operator A may develop a common NW slice with operator B, which will be described later.

The operator B network in this embodiment is a network operated by network operator B (operator B). Here, for example, operator B may develop a common NW slice with operator A.

The LADN (Local Area Data Network) in this embodiment is a DN to which a UE can connect only in a specific location, and provides connectivity to a specific DNN (that is, LADN DNN).

The LADN information in this embodiment is information related to LADN. The LADN information may be information indicating a specific LADN that can be used by the UE. The LADN information may include LADN DNN and LADN service area information. The LADN DNN may be information indicating an LADN, information indicating a DN treated as an LADN, or a DNN used when establishing a PDU session with the LADN. Further, the LADN service area information may be information indicating the LADN service area. Furthermore, LADN service area information may be provided as a set of tracking areas or as a TAI (Tracking area identity) list. Note that the LADN service area may be an area where a PDU session can be established with the LADN, or an area where connection to the LADN is possible.

A PDU session for LADN in this embodiment is a PDU session associated with a DNN associated with LADN. The PDU session for the LADN may be a PDU session established for the LADN. In other words, it may be a PDU session established between the UE and the LADN, or a PDU session used for user data communication between the UE and the LADN. Note that the PDU session for LADN may be a PDU session that can be established only in the LADN service area.

The 5G LAN-type service in this embodiment is a service that provides private communication by IP type or non-IP type communication via 5GS. Here, the IP type communication may be, for example, either an IPv4 type, an IPv6 type, or an IPv4v6 type, and the non-IP type communication may be, for example, an Ethernet type.

The 5G VN (Virtual Network) in this embodiment is a virtual network on 5GS that supports 5G LAN type services.

A 5G Virtual Network (VN) Group in this embodiment is a group composed of a plurality of UEs used for private communication for 5G LAN type services.

Information about the 5G VN group may include a 5G VN group ID, 5G VN group membership, and 5G VN group data, and 5GS uses this information to support management of the 5G VN group. do. Here, the 5G VN group ID may be an External Group ID and an Internal Group ID, which are used to identify the 5G VN group. For 5GVN group membership, GPSI (Generic Public Subscription Identifier) may be used to uniquely identify a UE that is a 5G VN group member. The 5G VN group data may include information such as a PDU session type, DNN and S-NSSAI, and an application descriptor.

Here, the 5G VN group may be associated with the DNN on a one-to-one basis. In other words, one 5G VN group may be associated with one DNN, and a specific 5G VN group may be specified by a specific DNN. Furthermore, the DNN, which is the first identification information, and the 5G VN group may be associated in a one-to-many or many-to-one manner. In other words, one DNN may be associated with multiple 5G VN groups, and one 5GVN group may be associated with multiple DNNs.

A PDU session for 5G VN Group in this embodiment is a PDU session by a DNN associated with the 5G VN group. A PDU session for a 5G VN group may be a PDU session established by UE_A10 using a DNN associated with the 5G VN group in order to connect (access or participate) to the 5G VN group. In other words, UE_A10 connecting to a 5G VN group may mean that UE_A10 establishes a PDU session for the 5G VN group.

In addition, the UE that has established the PDU session for the 5G VN group performs user data communication using the PDU session for the 5G VN group with other member UEs that are accessing the same 5G VN group. It may be possible to do so.

Note that the PDU session type of the PDU session for the 5G VN group may be an IP type or a non-IP type, and the IP type may be, for example, either an IPv4 type, an IPv6 type, or an IPv4v6 type. Possibly, the non-IP type may be, for example, an Ethernet type, and any mode for session service continuation (SSC mode 1, SSC mode 2, or SSC mode 3) is set. You can leave it there.

The first state in this embodiment is a state in which each device has completed the registration procedure and the PDU session establishment procedure, and the UE_A 10 and/or each device has established a PDU session for the 5G VN group. Here, UE_A10 and/or each device may be in a state in which UE_A10 is registered with the network (RM-REGISTERED state) by completing the registration procedure, and UE_A10 may be in a state where UE_A10 is registered with the network (RM-REGISTERED state) by completing the PDU session establishment procedure. It may be in a state in which a session establishment acceptance message has been received.

The first identification information in this embodiment may be a DNN (Data Network Name) associated with a 5G VN group. Here, the DNN, which is the first identification information, and the 5G VN group may have a one-to-one correspondence. In other words, one 5G VN group may be associated with one DNN, and a specific 5G VN group may be specified by a specific DNN.

The UE_A10 may send/provide the first identification information to the network in the PDU session establishment procedure to access the 5G VN group. More specifically, UE_A10 sends a NAS message requesting PDU session establishment including the first identification information, and receives a PDU session establishment acceptance message based on the first identification information from the core network. Thereby, a PDU session for the 5G VN group may be established.

Here, if UE_A10 transmits a NAS message for requesting PDU session establishment without including the first identification information in the PDU session establishment procedure, AMF that received the NAS message will , a PDU session for the 5G VN group may be established using the first identification information selected based on user subscription information, network settings, network policy, or the like.

Additionally, the DNN used in a PDU session that supports EPS interworking must be associated with the APN included in the default EPS bearer context of the PDN connection used when the PDU session is moved to EPS. However, there may be no APN associated with the DNN indicated by the first identification information.

The second identification information in this embodiment may be information indicating a set of EPS (Evolved Packet System) bearer contexts for the PDU session (Mapped EPS bearer contexts IE). Here, the second identification information may be an information element assigned from the SMF when the UE establishes a PDU session in 5GS. Furthermore, the second identification information may be the context of the EPS bearer used in the PDN connection when the PDU session established in 5GS is moved to the EPS by handover.

Further, the second identification information may be identification information included in the PDU session establishment acceptance message when the PDU session that the UE_A10 establishes in the PDU session establishment procedure supports interworking with the EPS. Conversely, if the second identity is not included in the PSU Session Establishment Accept message, it may mean that the established PDU session does not support interworking with the EPS and cannot be transferred to the EPS by handover. It doesn't have to be possible to move it.

Furthermore, if the PDU session established by UE_A10 in 5GS is an LADN PDU session, and/or a multi-homed IPv6 PDU session, and/or for a 5G VN group. PDU session, the SMF does not need to assign a second identity.

For example, a PDU session for a 5GN VN group may be a PDU session that is established when UE_A10 and/or core network B_199 selects and uses a DNN associated with a 5GN VN group. Here, the DNN associated with the 5GN VN group used to establish the PDU session for the 5GN VN group may be the first identification information, and further, the PDU session for the established 5G VN group is , the second identification information may not be assigned.

Next, the initial procedure in this embodiment will be explained using FIG. 9. Hereinafter, the initial procedure is also referred to as the main procedure, and the main procedure includes a registration procedure, a UE-led PDU session establishment procedure, and a handover procedure. Details of the registration procedure, PDU session establishment procedure, and handover procedure will be described later.

Specifically, as each device executes a registration procedure (S900), UE_A10 transitions to a state registered in the network (RM-REGISTERED state). Next, by each device executing the PDU session establishment procedure (S902), UE_A10 establishes a PDU session with DN_A5, which provides PDU connection service, via core network_B190, and connects each device. transitions to the first state (S904). Note that the PDU session established here may be a PDU session for a 5G VN group, or may be a PDU session based on a DNN associated with the 5G VN group. It is also assumed that this PDU session is established via the access network, 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. At this time, this PDU session will be established via the access network, UPF_C239, and UPF_A235. Next, each device in the first state may execute a handover procedure at any timing (S906). Here, the handover procedure may be a UE-initiated or network-initiated inter-system handover procedure from 5GS to EPS. Further, the inter-system handover procedure from 5GS to EPS may be a procedure for transferring any PDU sessions established in the first state from 5GS to EPS.

Note that each device may exchange various capability information and/or various request information of each device during the registration procedure, PDU session establishment procedure, and/or handbar procedure. In addition, when each device exchanges various information and/or negotiates various requests in the registration procedure, each device exchanges various information and/or negotiates various requests in the PDU session establishment procedure and/or handover procedure. You may or may not. In addition, if each device does not exchange various information and/or negotiate various requests in the registration procedure, each device must exchange various information and/or negotiate various requests in the PDU session establishment procedure and/or handover procedure. May be implemented. Furthermore, even if each device exchanges various information and/or negotiates various requests through the registration procedure, each device exchanges various information and/or negotiates various requests through the PDU session establishment procedure and/or handover procedure. You may.

Furthermore, each device may execute the PDU session establishment procedure during the registration procedure or after the registration procedure is completed. Additionally, when the PDU session establishment procedure is performed during the registration procedure, the PDU session establishment request message may be included in the registration request message and sent/received, and the PDU session establishment accept message may be sent/received included in the registration accept message. The PDU session establishment completion message may be included in the registration completion message and may be transmitted and received, and the PDU session establishment rejection message may be included in the registration rejection message and transmitted and received. Additionally, if 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 return to a state where the PDU session is established between each device. You may transition.

In addition, by sending and receiving each control message described in this procedure, each device involved in this procedure sends and receives one or more pieces of identification information included in each control message, and stores each sent and received identification information as a context. Good too.

[1.3.1. Overview of registration procedure]
First, an overview of the registration procedure will be explained. The registration procedure is a procedure for UE_A10 to take the lead in registering to the network (access network and/or core network_B190 and/or DN_A5). If the UE_A10 is not registered in the network, it can execute this procedure at any timing such as when the power is turned on. In other words, UE_A10 may start this procedure at any timing as long as it is in a non-registered state (RM-DEREGISTERED state). Furthermore, each device may transition to a registered state (RM-REGISTERED state) based on completion of the registration procedure.

Furthermore, this procedure is used to update the location registration information of UE_A10 in the network, and/or to periodically notify the status of UE_A10 from UE_A10 to the network, and/or to update specific parameters regarding UE_A10 in the network. This procedure may be used.

UE_A10 may start this procedure when performing mobility across TAs. In other words, UE_A10 may start this procedure when moving to a TA different from the TA indicated in the TA list it holds. Furthermore, UE_A10 may start this procedure when the timer it is running expires. Further, the UE_A 10 may initiate this procedure when the context of each device needs to be updated due to disconnection or invalidation (also referred to as deactivation) of a PDU session. Furthermore, the UE_A10 may initiate this procedure when there is a change in the capability information and/or preferences regarding the PDU session establishment of the UE_A10. Furthermore, UE_A10 may start this procedure periodically. Note that the UE_A 10 is not limited to these, and can execute this procedure at any timing as long as a PDU session is established.

[1.3.1.1. Registration procedure example]
An example of a procedure for executing the registration procedure will be explained using FIG. 10. In this chapter, this procedure refers to the registration procedure. Each step of this procedure will be explained below.

First, UE_A10 performs the registration procedure by sending a Registration Request message to AMF_A240 (S1000) (S1002) (S1004) via NR node (also referred to as gNB)_A122 and/or ng-eNB. Start. In addition, the UE_A10 includes and transmits an SM (Session Management) message (for example, a PDU session establishment request message) in the registration request message, or transmits an SM message (for example, a PDU session establishment request message) together with the registration request message. By doing so, procedures for session management (SM) such as PDU session establishment procedures may be initiated during the registration procedure.

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

Note that the registration request message is a NAS (Non-Access-Stratum) message sent and received on the N1 interface. Furthermore, the RRC message is a control message transmitted and received between the UE_A10 and the NR node_A122 and/or ng-eNB. Further, NAS messages are processed in the NAS layer, RRC messages are processed in the RRC layer, and the NAS layer is a layer higher than the RRC layer.

Additionally, if there are multiple NSIs requesting registration, UE_A10 may send a registration request message for each NSI, or may send multiple registration request messages in one or more RRC messages. good. Further, the plurality of registration request messages described above may be sent as one registration request message while being included in one or more RRC messages.

When AMF_A 240 receives a registration request message and/or a control message different from the registration request message, it performs a first condition determination. The first condition determination is for determining whether AMF_A240 accepts the request from UE_A10. In the first condition determination, the AMF_A 240 determines whether the first condition determination is true or false. AMF_A240 starts procedure (A) in this procedure if the first condition determination is true (i.e., the network accepts the request of UE_A10), and if the first condition determination is false (i.e. , if the network does not accept the request from UE_A10), the procedure (B) in this procedure is started.

Below, the steps when the first condition determination is true, that is, each step of the procedure (A) in this procedure, will be explained. AMF_A240 executes the fourth condition determination and starts procedure (A) in this procedure. The fourth condition determination is for determining whether or not AMF_A 240 transmits and receives SM messages to and from SMF_A 230. In other words, the fourth condition determination may be to determine whether or not the AMF_A 240 executes the PDU session establishment procedure during the main procedure. AMF_A240 selects SMF_A230 and sends/receives SM messages with the selected SMF_A230 when the fourth condition determination is true (that is, when AMF_A240 sends and receives SM messages with SMF_A230). are executed, and if the fourth condition determination is false (that is, AMF_A 240 does not perform transmission/reception of SM messages with SMF_A 230), these are omitted (S1006). Note that when AMF_A 240 receives an SM message indicating rejection from SMF_A 230, it may cancel procedure (A) in this procedure and start procedure (B) in this procedure.

Furthermore, AMF_A240 sends a Registration Accept message to UE_A10 via NR node_A122 based on the reception of the registration request message from UE_A10 and/or the completion of sending and receiving the SM message with SMF_A230. (S1008). For example, if the fourth condition determination is true, AMF_A240 may transmit a registration acceptance message based on receiving the registration request message from UE_A10. Further, if the fourth condition determination is false, AMF_A 240 may transmit a registration acceptance message based on completion of transmission and reception of the SM message with SMF_A 230. Here, the registration acceptance message may be sent as a response message to the registration request message. In addition, the registration acceptance message is a NAS message sent and received on the N1 interface. For example, AMF_A240 sends it to NR node_A122 as a control message for the N2 interface, and NR node_A122, which receives this message, sends an RRC message to UE_A10. It may also be included in the transmission.

Further, if the fourth condition determination is true, the AMF_A240 includes and transmits an SM message (e.g., PDU session establishment accept message) in the registration accept message, or sends an SM message (e.g., PDU session establishment accept message) together with the registration accept message. A session establishment acceptance message) may also be sent. This transmission method may be executed when an SM message (for example, a PDU session establishment request message) is included in the registration request message and the fourth condition determination is true. Further, this transmission method may be executed when an SM message (for example, a PDU session establishment request message) is included together with the registration request message, and the fourth condition determination is true. AMF_A240 may indicate that the procedure for the SM has been accepted by performing such a transmission method.

UE_A10 receives the registration acceptance message via NR node_A122 (S1008). By receiving the registration acceptance message, UE_A10 recognizes the contents of various types of identification information included in the registration acceptance message.

Next, UE_A10 transmits a registration complete message to AMF_A240 based on reception of the registration acceptance message (S1010). Furthermore, when the UE_A10 receives an SM message such as a PDU session establishment acceptance message, it may include the SM message such as the PDU session establishment completion message in the registration completion message and send it, or by including the SM message. , may indicate completing the procedure for SM. Here, the registration completion message may be sent as a response message to the registration acceptance message. In addition, the registration completion message is a NAS message sent and received on the N1 interface. For example, UE_A10 sends it to NR node_A122 by including it in an RRC message, and NR node_A122, which received this message, sends it to AMF_A240 on the N2 interface. It may also be sent as a control message.

AMF_A240 receives the registration completion message (S1010). Furthermore, each device completes the procedure (A) in this procedure based on the transmission and reception of the registration acceptance message and/or the registration completion message.

Next, the steps when the first condition determination is false, that is, each step of the procedure (B) in this procedure will be explained. 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 rejection message may be sent as a response message to the registration request message. In addition, the registration rejection message is a NAS message sent and received on the N1 interface. For example, AMF_A240 sends it to NR node_A122 as a control message for the N2 interface, and NR node_A122 that receives this sends an RRC message to UE_A10. It may also be included in the transmission. Further, the registration rejection message sent by AMF_A240 is not limited to this, as long as it is a message rejecting the request of UE_A10.

In addition, procedure (B) during this procedure may be started even if procedure (A) during this procedure is discontinued. In the procedure (A), if the fourth condition determination is true, AMF_A240 may include an SM message indicating rejection, such as a PDU session establishment rejection message, in the registration rejection message, or send the rejection message. A meaning SM message may be included to indicate that the procedure for SM was rejected. In that case, UE_A10 may further receive an SM message indicating rejection, such as a PDU session establishment rejection message, or may recognize that the procedure for SM has been rejected.

Furthermore, UE_A10 may recognize that its request has been rejected by receiving a registration reject message or by not receiving a registration accept message. Each device completes procedure (B) in this procedure based on the transmission and reception of the registration rejection message.

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

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

Further, the first condition determination may be performed based on identification information and/or subscriber information and/or operator policy included in the registration request message. For example, the first condition determination may be true if the network grants UE_A10's request. Further, the first condition determination may be false if the network does not permit the request from UE_A10. Furthermore, the first condition determination may be true if the network to which UE_A10 is registered and/or the device within the network supports the function requested by UE_A10, and is false if it does not support the function requested by UE_A10. good. Furthermore, the first condition determination may be true if the network is determined to be in a congested state, and may be false if it is determined that the network is not in a congested state. Note that the conditions for determining the truth of the first condition determination are not limited to the conditions described above.

Further, the fourth condition determination may be performed based on whether the AMF_A 240 has received the SM, or may be performed based on whether the registration request message includes an SM message. For example, the fourth condition determination may be true if AMF_A240 received the SM and/or the registration request message included an SM message, if AMF_A240 did not receive the SM, and /Or it may be false if the registration request message did not include an SM message. Note that the conditions for determining the truth of the fourth condition determination are not limited to the conditions described above.

[1.3.2.Outline 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 explained. Hereinafter, the PDU session establishment procedure is also referred to as this procedure. This procedure is a procedure for each device to establish a PDU session. Note that each device may execute this procedure after completing the registration procedure, or may execute this procedure during the registration procedure. Further, each device may start this procedure in a registered state, or may start this procedure at any timing after the registration procedure. Furthermore, each device may establish a PDU session based on completion of the PDU session establishment procedure. Furthermore, each device may establish multiple PDU sessions by executing this procedure multiple times.

[1.3.2.1.PDU session establishment procedure example]
An example of a procedure for executing a PDU session establishment procedure will be explained using FIG. 11. Each step of this procedure will be explained below. First, UE_A10 starts a PDU session establishment procedure by transmitting a PDU Session Establishment Request message to core network_B via access network_B (S1100).

Specifically, UE_A10 uses the N1 interface to transmit a PDU session establishment request message to AMF_A240 in core network_B190 via NR node_A122 (S1100). AMF_A receives the PDU session establishment request message and performs the third condition determination. The third condition determination is for AMF_A to determine whether to accept the request from UE_A10. In the third condition determination, AMF_A determines whether the fifth condition determination is true or false. Core network_B starts processing #1 in the core network if the third condition determination is true (S1101), and if the third condition determination is false, executes procedure (B) in this procedure. Start. Note that 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_B 190 and/or transmission and reception of a PDU session establishment request message between AMF_A and SMF_A.

Core network_B190 starts processing #1 within the core network. In process #1 in the core network, AMF_A240 selects SMF_A230 as the NF to which the PDU session establishment request message is routed, and sends or forwards the PDU session establishment request message to the selected SMF_A230 using the N11 interface. Good too. Here, the AMF_A 240 may select the SMF_A 230 as the routing destination based on the information included in the PDU session establishment request message. More specifically, the AMF_A240 determines the respective identification information obtained based on the reception of the PDU Session Establishment Request message, and/or subscriber information, and/or network capability information, and/or operator policy, and/or network The SMF_A 230 to route to may be selected based on the state and/or the context that the AMF_A 240 already maintains.

Note that the PDU session establishment request message may be a NAS message. Further, the PDU session establishment request message may be any message requesting establishment of a PDU session, and is not limited to this.

Here, UE_A10 may include the first identification information in the NAS message for requesting the establishment of a PDU session or the PDU session establishment request message, and by including this identification information, UE_A10 can respond to the request from UE_A10. may be shown.

Furthermore, the UE_A10 requests the establishment of a PDU session for the 5G VN group by transmitting the first identification information in a NAS message for requesting the establishment of a PDU session or in a PDU session establishment request message. It may also indicate the 5G VN group to which the PDU session, requested by UE_A10, belongs, or it may indicate the 5G VN group to which the PDU session is scheduled to belong from now on.

Note that the UE_A10 determines whether to include the first identification information in the NAS message for requesting the establishment of a PDU session or in the PDU session establishment request message, based on the capability information of the UE_A10 and/or policies such as the UE policy. And/or it may be determined based on the preferences of the UE_A10 and/or the application (upper layer). Note that the determination by the UE_A10 of whether to include the first identification information in the NAS message for requesting establishment of a PDU session or in the PDU session establishment request message is not limited to this.

The SMF_A 230 in the core network_B 190 receives the PDU session establishment request message and performs the third condition determination. The third condition determination is for SMF_A230 to determine whether to accept the request from UE_A10. In the third condition determination, SMF_A230 determines whether the third condition determination is true or false. SMF_A230 starts procedure (A) in this procedure if the third condition determination is true, and starts procedure (B) in this procedure if the third condition determination is false. Note that the steps when the third condition determination is false will be described later.

Below, the steps when the third condition determination is true, that is, each step of the procedure (A) in this procedure, will be explained. The SMF_A 230 selects the UPF_A 235 to establish a PDU session and executes the eleventh condition determination.

Here, the eleventh condition determination is for determining whether each device executes process #2 within the core network. Here, processing #2 in the core network is the initiation and/or execution of a PDU session establishment authentication procedure by each device, and/or the session establishment request message between SMF_A and UPF_A in core network_B190. and/or the transmission and reception of a Session Establishment response message (S1103). In the eleventh condition determination, SMF_A230 determines whether the eleventh condition determination is true or false. SMF_A230 starts the PDU session establishment authentication and approval procedure when the eleventh condition determination is true, and omits the PDU session establishment authentication and approval procedure when the eleventh condition determination is false. Note that details of the PDU session establishment authentication approval procedure of process #2 in the core network will be described later.

Next, SMF_A230 sends a session establishment request message to the selected UPF_A235 based on the eleventh condition determination and/or completion of the PDU session establishment authentication approval procedure, and starts procedure (A) in this procedure. do. Note that, based on the completion of the PDU session establishment authentication approval procedure, the SMF_A 230 may start procedure (B) in this procedure without starting procedure (A) in this procedure.

Here, SMF_A230 includes each identification information obtained 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 one or more UPF_A 235 may be selected based on the context that the SMF_A 230 already maintains. Note that when multiple UPF_A 235 are selected, SMF_A 230 may transmit a session establishment request message to each UPF_A 235.

UPF_A235 receives the session establishment request message and creates a context for the PDU session. Additionally, UPF_A 235 sends a session establishment response message to SMF_A 230 based on receiving the session establishment request message and/or creating a context for the PDU session. Additionally, SMF_A 230 receives a session establishment response message. Note that the session establishment request message and the session establishment response message may be control messages sent and received on the N4 interface. Further, the session establishment response message may be a response message to the session establishment request message.

Further, the SMF_A 230 may perform address assignment of an address to be assigned to the UE_A 10 based on the reception of the PDU session establishment request message and/or the selection of the UPF_A 235 and/or the reception of the session establishment response message. Note that the SMF_A 230 may assign the address to be assigned to the UE_A 10 during the PDU session establishment procedure, or after the completion of the PDU session establishment procedure.

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

Furthermore, based on the completion of address assignment of the address to be assigned to UE_A10, SMF_A230 may include the assigned address in a PDU session establishment acceptance message and send it to UE_A10, or after completing the PDU session establishment procedure, SMF_A230 may transmit the assigned address to UE_A10. You may.

SMF_A230 sends the message to UE_A10 via AMF_A240 based on the reception of the PDU Session Establishment Request message and/or the selection of UPF_A235 and/or the reception of the Session Establishment Response message and/or the completion of address assignment of the address to be assigned to UE_A10. A PDU session establishment accept message is transmitted (S1110).

Specifically, SMF_A230 sends a PDU session establishment accept message to AMF_A240 using the N11 interface, and AMF_A240, which received the PDU session establishment accept message, sends a PDU session establishment accept message to UE_A10 using the N1 interface. .

Note that when the PDU session is a PDN connection, the PDU session establishment acceptance message may be a PDN connectivity accept message. Further, the PDU session establishment acceptance message may be an N11 interface and a NAS message sent and received on the N1 interface. Further, the PDU session establishment acceptance message is not limited to this, and any message indicating that establishment of a PDU session has been accepted may be used.

UE_A10 receives the PDU session establishment acceptance message from SMF_A230. By receiving the PDU session establishment acceptance message, UE_A10 recognizes the contents of various types of identification information included in the PDU session establishment acceptance message.

Here, the PDU session establishment acceptance message transmitted by SMF_A230 and received by UE_A10 may include either the first identification information or the second identification information, or either of these identification information may be included. may indicate that the request of UE_A10 has been accepted. For example, if SMF_A230 includes the first identification information in the PDU Session Establishment Accept message, SMF_A230 may not include the second identification information; If identification information is included, the first identification information may not be included.

Further, if the SMF_A230 includes the first identification information and does not include the second identification information in the PDU Session Establishment Acceptance message, even if the UE_A10 indicates that the establishment of the PDU session for the 5G VN group is accepted. Alternatively, this PDU session may indicate that intersystem interworking with the EPS is not supported and handover to the EPS is not allowed, and the UE_A10 may recognize these. Conversely, if SMF_A230 includes the second identity but not the first identity in the PDU Session Establishment Accept message, then this PDU session supports system-to-system interworking with EPS and UE_A10 may also indicate that this PDU session is not a PDU session for a 5G VN group, and the UE_A10 may recognize these. .

Here, if the DNN included in the PDU session establishment acceptance message by SMF_A230 is the first identification information, SMF_A230 does not need to include the second identification information in the PDU session establishment acceptance message.

Conversely, if the DNN included in the PDU session establishment acceptance message by SMF_A230 is not the first identification information, SMF_A230 may include second identification information in the PDU session establishment acceptance message.

In other words, a PDU session for a 5G VN group may not have system-to-system interworking with EPS and handover to EPS is allowed, or conversely, system-to-system interworking with EPS may not be allowed. PDU sessions that support interworking and are allowed handover to EPS may not be PDU sessions for 5G VN groups.

Note that SMF_A230 determines which identification information to include in the PDU session establishment acceptance message among the first identification information and/or second identification information, based on the received identification information and/or network capability information, and/or may be determined based on policies such as operator policies, and/or network conditions, and/or user subscription information. Note that the determination by SMF_A230 of whether to include either or both of these pieces of identification information in the PDU session establishment acceptance message is not limited to these.

Further, the first identification information may be the same DNN as that included in the NAS message or the PDU session establishment request message for the above-mentioned UE_A10 to request establishment of a PDU session. Or, the first identification information is the 5G VN selected by the AMF or other core network equipment, regardless of the times that the UE_A10 includes in the NAS message or the PDU session establishment request message for requesting the establishment of a PDU session. It may also be a DNN associated with a group.

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 completion message and performs a second condition determination.

Specifically, UE_A10 sends a PDU session establishment complete message to AMF_A240 using the N1 interface, and AMF_A240, which received the PDU session establishment complete message, sends a PDU session establishment complete message to SMF_A230 using the N11 interface. .

Note that 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. Further, the PDU session establishment completion message may be a NAS message sent and received on the N1 interface and the N11 interface. Further, the PDU session establishment completion message may be any response message to the PDU session establishment acceptance message, and is not limited to this, and may be any message indicating that the PDU session establishment procedure is completed.

The second condition determination is for SMF_A230 to determine the type of message on the N4 interface to be sent and received. If the second condition determination is true, processing #3 within the core network may be started (S1115). Here, processing #3 within the core network may include transmission and reception of a session modification request message and/or transmission and reception of a session modification response message. SMF_A230 sends a session change request message to UPF_A235, and further receives a session change acceptance message sent by UPF_A235 that received the session change request message. Furthermore, if the second condition determination is false, SMF_A230 executes process #2 within the core network. That is, SMF_A sends a session establishment request message to UPF_A 235, and further receives a session change acceptance message sent by UPF_A 235 that received the session establishment request message.

Each device transmits and receives a PDU session establishment completion message, and/or a session change response message, and/or a session establishment response message, and/or transmits and receives an RA (Router Advertisement) during this procedure. Complete procedure (A).

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

Specifically, SMF_A230 sends a PDU session establishment refusal message to AMF_A240 using the N11 interface, and AMF_A240, which has received the PDU session establishment request message, sends a PDU session establishment refusal message to UE_A10 using the N1 interface. .

Note that when the PDU session is a PDN connection, the PDU session establishment rejection message may be a PDN connectivity rejection message. Further, the PDU session establishment refusal message may be an N11 interface and a NAS message sent and received on the N1 interface. Further, the PDU session establishment rejection message is not limited to this, and any message indicating that establishment of a PDU session has been rejected may be used.

[1.3.3. Overview of handover procedure]
Next, an overview of the handover procedure will be explained. Hereinafter, the handover procedure will also be referred to as this procedure. This procedure may be a procedure for a UE- or network-initiated inter-system handover from 5GS to EPS. Further, the intersystem handover procedure from 5GS to EPS may be a procedure for moving established PDU sessions from 5GS to EPS, and for moving PDU sessions supporting interworking with EPS to EPS. This procedure may be used.

If the UE receives the second identification information in the PDU session establishment procedure, the established PDU session may be able to be transferred to the EPS.

Conversely, if the UE does not receive the second identification information in the PDU session establishment procedure, the established PDU session may not be able to be transferred to the EPS.

Here, PDU sessions supporting system-to-system interwork with EPS can be transferred to EPS based on handover procedures. Conversely, this procedure is not executed for PDU sessions that do not support interworking with EPS. In other words, the UE and each device must not perform this procedure for PDU sessions that do not support interworking with EPS. In other words, in an inter-system change from N1 mode to S1 mode, PDU sessions for 5GVN groups should not be moved to EPC. Furthermore, if the UE_A 10 has established multiple PDU sessions, only the PDU sessions that support system-to-system interwork with the EPS may be moved to the EPS by this procedure.

Further, this procedure may be composed of different procedures initiated by different devices based on the presence or absence of the N26 interface between the MME and AMF and the status of each device in the UE and the network. For example, in the case of handover from 5GS to EPS when there is an N26 interface, it may be a network-initiated procedure initiated by NG-RAN. For example, in the case of movement from 5GS to EPS, if there is an N26 interface and it is idle mode mobility, or if there is no N26 interface, the UE will take the initiative in moving to the destination EPS. It may be initiated by a Tracking Area Update procedure or an Initial Attach procedure.

[1.3.3.1. Handover procedure example]
The behavior when handing over the PDU session for the 5G VN group established in the first state from 5GS to EPS between systems will be described. Here, the PDU session for the 5G VN group is a PDU session that is established when the PDU session establishment acceptance message includes the first identification information and does not include the second identification information, as described above.

This section describes examples of cases in which this procedure should not be executed. Below are the cases when there is an N26 interface and handover from 5GS to EPS, when there is an N26 interface and Idle Mode Mobility from 5GS to EPS, or when there is no N26 interface. The behavior of the UE and each device will be described below.

First, when there is an N26 interface and there is a handover from 5GS to EPS, the procedure is that the NG-RAN via the PDU session for the 5G VN group established in the first state is handed over to the E-UTRAN. You may begin by determining that you need a Next, the NG-RAN that has decided to perform the handover sends a handover request to the AMF, and based on reception of the handover request, the AMF sends an EPS for the PDU session indicated by the second identification information to the SMF. Sends a message (Nsmf_PDUSession_Context Request) containing information indicating a set of bearer contexts (mapped EPS Bearer Contexts).

Here, in the PDU session establishment procedure, the PDU session for the 5G VN group, which is the target of handover, receives information indicating a set of EPS bearer contexts for the PDU session indicated by the second identification information (mapped EPS Bearer Contexts) has not been assigned by SMF and interworking with EPS is not supported, so the above NG-RAN may terminate this procedure without deciding to handover to EPS, or After determining the handover and transmitting the handover request to the AMF, the AMF that has received the handover request may terminate this procedure without transmitting the message to the SMF.

Next, if there is an N26 interface and there is an Idle Mode Mobility from 5GS to EPS, or if there is no N26 interface, the tracking area update procedure (Tracking Area Update ( It may be started by the TAU) procedure or the Initial Attach procedure.

Here, in the PDU session establishment procedure, the PDU session for the 5G VN group, which is the target of handover, receives information indicating a set of EPS bearer contexts for the PDU session indicated by the second identification information (mapped EPS Bearer Contexts) has not been assigned from SMF and interworking with EPS is not supported, so the UE does not execute the tracking area update procedure or initial attach procedure in the destination EPS, and even after finishing this procedure. good.

From the above, the PDU session for the 5G VN group does not support interworking with EPS because the information indicating the set of EPS bearer contexts for the PDU session (mapped EPS Bearer Contexts) is not allocated from SMF. Therefore, the procedure for moving the PDU session from 5GS to EPS does not need to be performed at the discretion of the UE or each device. In other words, in inter-system change from N1 mode to S1 mode, UE_A10 shall not move the PDU session for 5G VN group to EPS.

Furthermore, the PDU session for the 5G VN group may be used for transmitting and receiving user data in the 5GS without being moved to the EPS, and may be explicitly or implicitly released.

[2. Modification example]
The program that runs on the device related to the present invention may be a program that controls a central processing unit (CPU) or the like to cause the computer to function so as to realize the functions of the embodiments related to the present invention. Programs or information handled by programs are temporarily stored in volatile memory such as Random Access Memory (RAM), non-volatile memory such as flash memory, hard disk drive (HDD), or other storage system.

Note that a program for realizing the functions of the embodiments related to the present invention may be recorded on a computer-readable recording medium. The program recorded on this recording medium may be read into a computer system and executed. The "computer system" herein refers to a computer system built into the device, and includes hardware such as an operating system and peripheral devices. Furthermore, a "computer-readable recording medium" refers to a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a medium that dynamically stores a program for a short period of time, or any other computer-readable recording medium. Also good.

Additionally, each functional block or feature of the device used in the embodiments described above may be implemented or executed in an electrical circuit, such as an integrated circuit or multiple integrated circuits. An electrical circuit designed to perform the functions described herein may be a general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or combinations thereof. A general purpose processor may be a microprocessor or a conventional processor, controller, microcontroller, or state machine. The electric circuit described above may be composed of a digital circuit or an analog circuit. Furthermore, if advances in semiconductor technology lead to the emergence of an integrated circuit technology that replaces current integrated circuits, one or more aspects of the present invention may use a new integrated circuit based on that technology.

Note that the present invention is not limited to the above-described embodiments. In the embodiment, one example of the device is described, but the present invention is not limited to this, and can be applied to stationary or non-movable electronic equipment installed indoors or outdoors, such as AV equipment, kitchen equipment, etc. It can be applied to terminal devices or communication devices such as cleaning/washing equipment, air conditioning equipment, office equipment, vending machines, and other household equipment.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and may include design changes within the scope of the gist of the present invention. Further, the present invention can be modified in various ways within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included within the technical scope of the present invention. It will be done. Also included are configurations in which the elements described in each of the above embodiments are replaced with each other and have similar effects.

1 Mobile communication system
5DN_A
6 PDN_A
10 UE_A
20 UTRAN_A
22 NB_A
24 RNC_A
30 PGW_A
35 SGW_A
40 MME_A
45 eNB_A
50 HSS_A
80 E-UTRAN_A
90 Core network_A
120 NG-RAN_A
122 NR node_A
190 Core network_B
230 SMF_A
235 UPF_A
239 UPF_C
240 AMF_A

Claims (2)

A UE (User Equipment; terminal device),
In the PDU (Protocol Data Unit) session establishment procedure,
a transmitting/receiving unit that receives a PDU session establishment acceptance message from the core network;
a control unit for establishing a PDU session ;
The PDU session is a PDU session associated with a 5G VN (Virtual Network) group,
The PDU session establishment acceptance message does not include information indicating a set of EPS (Evolved Packet System) bearer contexts for the PDU session,
The control unit is characterized in that when the system is changed from N1 mode to S1 mode , the control unit recognizes that moving the PDU session to EPS is not permitted, and releases the PDU session. UE to do. A communication control method for a UE (User Equipment; terminal device), the method comprising:
In the PDU (Protocol Data Unit) session establishment procedure,
receiving a PDU session establishment acceptance message from the core network;
establishing a PDU session;
The PDU session is a PDU session associated with a 5G VN (Virtual Network) group,
The PDU session establishment acceptance message does not include information indicating a set of EPS (Evolved Packet System) bearer contexts for the PDU session,
When the system is changed from N1 mode to S1 mode , recognizing that moving the PDU session to EPS is not permitted and releasing the PDU session ;
A UE communication control method characterized by:

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