JP2021029007A - UE and communication control method - Google Patents

Abstract

To provide a communication method to determine whether or not to perform a procedure for handover when UE moves from a 5GS to an EPS or is handed over between the systems when a PDU session is connected to a 5G VN (Virtual Network) group.SOLUTION: When a PDU session established by UE is connected to a 5G VN (Virtual Network) group, a determination is made as to whether or not to perform a handover procedure for moving the PDU session to an EPC depending on whether a relevant information element is received from a network.SELECTED DRAWING: Figure 1

Description

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

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

In recent years, 3GPP has also been studying the next-generation communication technology and system architecture of 5G (5th Generation) mobile communication systems, which are next-generation mobile communication systems. In particular, 5GS (5GS) is a system that realizes 5G mobile communication systems. 5G System) is being specified (see Non-Patent Document 1 and Non-Patent Document 2). In 5GS, technical issues for connecting a wide variety of terminals to a cellular network are extracted and solutions are specified.

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 composed of a plurality of terminals (User Equipment; UE). The requirements include optimization and diversification of communication procedures to support type services (5G LAN-type Service), and optimization of system architecture in line with optimization and diversification of communication procedures.

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 composed of multiple UEs, in a virtual network configured on 5GS is being studied (Non-Patent Document 1 and Non-Patent). See Document 2 and Non-Patent Document 3).

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

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a communication control method when a PDU session is for a 5G VN group at the time of handover between systems. That is.

The UE (User Equipment) of the present invention includes a transmission / reception unit for receiving a PDU session establishment acceptance message from a core network and a control unit for establishing a PDU session in a PDU (Protocol Data Unit) session establishment procedure. 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. Not included, the UE does not transfer the PDU session to EPS when the system is changed from N1 mode to S1 mode.

The UE (User Equipment) communication control method of the present invention includes a step of receiving a PDU session establishment acceptance message from a core network and a step of establishing a PDU session in a PDU (Protocol Data Unit) session establishment procedure. The PDU session is a PDU session associated with a 5G VN (Virtual Network) group, and the PDU session establishment acceptance message is a set of EPS (Evolved Packet System) bearer contexts for the PDU session. The UE does not transfer the PDU session to the EPS when the system is changed from the N1 mode to the S1 mode without including the information indicating the above.

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.

It is a figure which shows the outline of the mobile communication system. It is a figure which shows an example of the configuration of an access network in a mobile communication system. It is a figure which shows an example of the configuration of the core network_A in a mobile communication system. It is a figure which shows an example of the configuration of the core network_B in the mobile communication system. It is a figure which shows the device configuration of UE. It is a figure which shows the device configuration of an eNB / NR node. It is a figure which shows the apparatus configuration of MME / AMF. It is a figure which shows the apparatus configuration of SMF / PGW / UPF. It is a figure which shows the initial procedure. It is a figure which shows the registration procedure. It is a figure which shows the 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]
The outline of the mobile communication system in this embodiment will be described with reference to FIGS. 1, 2, 3, and 4. FIG. 2 is a diagram showing details of an access network among the mobile communication systems of FIG. FIG. 3 is a diagram showing details of the core network_A90 mainly in the mobile communication system of FIG. FIG. 4 is a diagram showing details of the core network_B190 mainly in the mobile communication system of FIG. As shown in FIG. 1, the mobile communication system 1 in 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; Access Network) _A, and an access network _B. , Core Network (CN) _A90, Core Network _B190, Packet Data Network (PDN) _A6, and 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 is 5GS (5G System). It may be referred to as (5G mobile communication system), and the configuration of 5GS and EPS is 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 wireless access network. Sometimes DN_A5, PDN_A6 or a combination thereof may also be referred to as DN.

Here, UE_A10 can connect 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 a device. In addition, UE_A10 may include a UICC (Universal Integrated Circuit Card) or an eUICC (Embedded UICC). Further, UE_A10 may be a terminal device capable of wireless connection, or may be an ME (Mobile Equipment), MS (Mobile Station), CIoT (Cellular Internet of Things) terminal (CIoT UE), or the like.

UE_A10 can also connect to the access network and / or the core network. UE_A10 can also connect to DN_A and / or PDN_A via the access network and / or core network. UE_A10 sends and receives (communicate) user data to and from DN_A and / or PDN_A using a PDU (Protocol Data Unit or Packet Data Unit) session and / or PDN (Packet Data Network) connection (also called PDN connection). ). Further, the communication of user data is not limited to IP (Internet Protocol) communication (IPv4 or IPv6), for example, EPS may be non-IP communication, and 5GS may be Ethernet (registered trademark) communication or Unstructured communication. There may be.

Here, IP communication is data communication using IP, and is data communication realized by sending and receiving an IP packet to which an IP header is added. The payload portion constituting the IP packet may include user data sent and received by UE_A10. Further, non-IP communication is data communication that does not use IP, and is data communication that is realized by sending and receiving data to which an IP header is not added. For example, non-IP communication may be data communication realized by sending and receiving application data to which an IP address is not assigned, or UE_A10 may be provided with another header such as a Mac header or an Ethernet (registered trademark) frame header. User data to be sent and received may be sent and received.

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

In addition, UE_A10 can execute transmission / reception of user data by using a device such as an application server arranged in DN_A5 and a PDU session. In other words, the PDU session can transfer user data transmitted and received between UE_A10 and a device such as an application server arranged in DN_A5. In addition, each device (UE_A10, device in the access network, and / or device in the core network, and / or device in the data network) manages one or more identifications associated with each PDU session. You may. These identification information includes 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). ) At least one of the identification information and the access network identification information may be included, and other information may be further included. Further, when a plurality of PDU sessions are established, the identification information associated with the PDU session may have the same content or different contents. Further, the NSI identification information is information that identifies NSI, and may be hereinafter NSI ID or Slice Instance ID.

As the access network_A and access network_B, as shown in Fig. 2, UTRAN (Universal Terrestrial Radio Access Network) _A20, E-UTRAN (Evolved Universal Terrestrial Radio Access Network) _A80, NG-RAN (5G-) It may be any of RAN) _A120. In the following, 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 and non-3GPP AN will be referred to as non-3GPP access or non-3GPP access network. Sometimes referred to. Each radio access network includes a device (for example, a base station device or an access point) to which the UE_A10 actually connects.

For example, E-UTRAN_A80 is an LTE access network and is configured to include one or more eNB_A45s. eNB_A45 is a radio base station to which UE_A10 connects with E-UTRA (Evolved Universal Terrestrial Radio Access). Further, when there are a plurality of eNBs in E-UTRAN_A80, each eNB may be connected to each other.

Further, NG-RAN_A120 is a 5G access network, which may be (R) AN shown in FIG. 4, and includes one or more NR nodes (New Radio Access Technology node) _A122 and / or ng-eNB. It is composed. In addition, NR node_A122 is a radio base station to which UE_A10 is connected by 5G radio access (5G Radio Access), and is also referred to as gNB. The ng-eNB may be an eNB (E-UTRA) that constitutes a 5G access network, may be connected to the core network_B190 via NR node_A, or may be directly connected to the core network_B190. You may be. Further, when there are a plurality of NR node_A122 and / or ng-eNB in NG-RAN_A120, each NR node_A122 and / or ng-eNB may be connected to each other.

The NG-RAN_A120 may be an access network composed of E-UTRA and / or 5G Radio Access. In other words, NG-RAN_A120 may contain 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 for a 3G mobile communication system, and is composed of RNC (Radio Network Controller) _A24 and NB (Node B) _A22. NB_A22 is a radio base station to which UE_A10 is connected by 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 the core network_A90 and NB_A22, and UTRAN_A20 may be configured to include one or more RNCs. Also, RNC_A24 may be connected to one or more NB_A22s.

In this specification, the fact that UE_A10 is connected to each radio access network means that it is connected to a base station device, an access point, or the like included in each radio access network, and data, signals, etc. to be transmitted and received. It also means that it goes through a base station device or an access point. The control message sent and received between UE_A10 and the core network_B190 may be the same control message regardless of the type of access network. Therefore, sending and receiving messages between UE_A10 and core network_B190 via NR node_A122 may be the same as sending and receiving messages between UE_A10 and core network_B190 via eNB_A45.

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

Further, DN_A5 and PDN_A6 are data networks (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. Further, DN_A5 may include a connected communication terminal. Therefore, connecting to DN_A5 may be connecting to a communication terminal or server device arranged in DN_A5. Further, sending and receiving user data to and from DN_A5 may be sending and receiving user data to and from a communication terminal or server device arranged in DN_A5. Further, although DN_A5 is outside the core network in FIG. 1, it may be inside the core network.

Further, the core network_A90 and / or the core network_B190 may be configured as devices in one or more core networks. Here, the device in the core network may be a device that executes a part or all of the processing or function of each device included in the core network_A90 and / or the core network_B190. The device in the core network may be referred to as a core network device.

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

Next, the core network_A90 will be described. 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) Node), SCEF, at least one may be included. Then, these may be configured as NF (Network Function). NF may refer to a processing function configured in the network. In addition, the core network_A90 can be connected to a plurality of radio access networks (UTRAN_A20, E-UTRAN_A80).

For simplification, FIG. 3 shows only HSS (HSS_A50), PGW (PGW_A30), SGW (SGW_A35) and MME (MME_A40), but other devices and / or NFs. Does not mean that is not included. For simplification, UE_A10 is also referred to as UE, HSS_A50 is referred to as HSS, PGW_A30 is referred to as PGW, SGW_A35 is referred to as SGW, MME_A40 is referred to as MME, and DN_A5 and / or PDN_A6 is also referred to as DN or PDN.

The following is a brief description of each device included in the core network_A90.

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

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

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

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

MME_A40 is a control device that is connected to SGW_A35, an access network, HSS_A50, and SCEF, and performs location information management including mobility management of UE_A10 and access control via the access network. Further, MME_A40 may include a function as a session management device for managing the 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 the MME_A40 may be connected to the SGW_A35, the access network, the SCEF, and the HSS_A50, similar to the MME_A40. Furthermore, MME_A40 may be connected to AMF (Access and Mobility Management Function).

Further, when a plurality of MMEs are included in the core network_A90, the MMEs may be connected to each other. As a result, the context of UE_A10 may be sent 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, in other words, it may be a control device of the control plane (C-Plane; CP).

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

Further, the MME_A40 may be a relay device that transfers user data as a gateway between the core network_A90 and the access network. The user data transmitted / received using MME_A40 as a gateway may be small data.

Further, MME_A40 may be an NF such as UE_A10 that plays a role of mobility management, or an NF that manages one or more NSIs. In addition, MME_A40 may be an NF that plays one or more of these roles. The NF may be one or more devices arranged in the core network_A90, and may also be a CP function for control information and / or a control message (hereinafter, CPF (Control Plane Function) or Control Plane Network Function). It may be a shared CP function shared between multiple network slices.

Here, NF is a processing function configured in the network. That is, the NF may be a functional device such as MME, SGW, PGW, CPF, AMF, SMF, or UPF, or may be function or capability 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 may be a functional device for realizing a plurality of functions. For example, the NF for realizing the MM function and the NF for realizing the SM function may exist separately, or there is an NF for realizing both the MM function and the SM function. You may.

HSS_A50 is a management node that is connected to MME_A40, AAA, and SCEF and manages subscriber information. The subscriber information of HSS_A50 is referred to when, for example, access control of MME_A40 is performed. Further, the HSS_A50 may be connected to a position management device different from that of the MME_A40. For example, HSS_A50 may be connected to CPF_A140.

Further, HSS_A50 and UDM (Unified Data Management) _A245 may be configured as different devices and / or NFs, or may be configured as the same device and / or NFs.

AAA is connected to PGW30, HSS_A50, PCRF, and WLAN ANa70, and controls access to UE_A10, which is connected via WLAN ANa70.

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

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

The ePDG is connected to PGW30 and WLAN ANb75, and delivers user data as a gateway between core network _A90 and WLAN ANb75.

The 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). Is. In addition, the SGSN has a PGW and SGW selection function, a UE_A10 time zone management function, and an MME_A40 selection function during handover to E-UTRAN.

SCEF is a relay device that is connected to DN_A5 and / or PDN_A6, MME_A40 and HSS_A50, and transfers user data as a gateway connecting DN_A5 and / or PDN_A6 and core network_A90. SCEF may be a gateway for non-IP communication. In addition, SCEF may have the ability to convert between non-IP communication and IP communication. In addition, a plurality of such gateways may be arranged in the core network_A90. In addition, multiple gateways connecting the core network_A90 with a single DN_A5 and / or PDN_A6 and / or DN may also be deployed. The SCEF may be configured outside the core network or inside the core network.

Next, the core network_B190 will be described. 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), and PCF (Policy Control). At least one of 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. .. Then, these may be configured as NF (Network Function). NF may refer to a processing function configured in the network.

For simplicity, Figure 4 shows only AMF (AMF_A240), SMF (SMF_A230), and UPF (UPF_A235), but others (devices and / or NFs (Network)). It does not mean that Function)) is not included. For simplicity, UE_A10 is also referred to as UE, AMF_A240 is also referred to as AMF, SMF_A230 is referred to as SMF, UPF_A235 is referred to as UPF, and DN_A5 is also referred to as DN.

Further, FIG. 4 shows 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. Here, the N1 interface is the interface between the UE and AMF, the N2 interface is the interface between (R) AN (access network) and AMF, and the N3 interface is (R) AN (access network). The interface between UPF, 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. , N11 interface is the interface between AMF and SMF. Communication can be performed between the devices by using these interfaces. Here, (R) AN is also referred to as NG RAN below.

The following is a brief description of each device included in the core network_B190.

First, AMF_A240 is connected to other AMF, SMF (SMF_A230), access networks (ie UTRAN_A20 and E-UTRAN_A80 and NG-RAN_A120), UDM, AUSF, PCF. AMF_A240 is used for registration management (Registration management), connection management (Connection management), reachability management (Reachability management), mobility management such as UE_A10 (Mobility management), 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 Signals with UE via N3IWF It may play a role of supporting transmission / reception, authenticating UEs connected via N3IWF, managing RM states (Registration Management states), managing CM states (Connection Management states), and so on. Further, one or more AMF_A240s may be arranged in the core network_B190. In addition, AMF_A240 may be an NF that manages one or more NSIs (Network Slice Instances). Further, AMF_A240 may be a shared CPNF (Control Plane Network Function) (CCNF) shared among a plurality of NSIs.

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 that UE, so AMF cannot reach the UE. is there. Also, in the RM-REGISTERED state, the UE is registered in the network, so the UE can receive services that require registration with the network.

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

In addition, SMF_A230 has a session management (Session Management) function for PDU sessions, IP address allocation and its management function for UEs, UPF selection and control function, and traffic to an appropriate destination. UPF setting function for routing, the function to notify that downlink data has arrived (Downlink Data Notification), and AN-specific (AN) that is sent to AN via AMF via N2 interface. 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, and the like. Further, SMF_A230 may be connected to AMF_A240, UPF_A235, UDM, and PCF.

The UPF_A235 is also connected to DN_A5, SMF_A230, other UPFs, and access networks (ie UTRAN_A20 and 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, Routing point feature that supports multi-homed PDU sessions, QoS processing for user planes, verification of uplink traffic, buffering of downlink packets, downlink data notification It may play a role such as a trigger function. Further, UPF_A235 may be a relay device that transfers user data as a gateway between DN_A5 and core network_B190. UPF_A235 may be a gateway for IP communication and / or non-IP communication. Further, UPF_A235 may have a function of transferring IP communication, and may have a function of converting non-IP communication and IP communication. Further, the plurality of gateways to be arranged may be a gateway connecting the core network_B190 and a single DN. The UPF_A235 may have connectivity with other NFs, or may be connected to each device via other NFs.

In addition, UPF_C239 (also referred to as branching point or uplink classifier), which is a UPF different from UPF_A235, may exist as a device or NF between UPF_A235 and the access network. If UPF_C239 is present, the PDU session between UE_A10 and DN_A5 will be established via the access network, UPF_C239, UPF_A235.

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

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

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

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

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

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

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

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

The S1 mode is a UE mode in which messages can be sent and received using the S1 interface. The S1 interface may be composed of an S1-MME interface, an S1-U interface, and an X2 interface that connects radio base stations.

The UE in S1 mode can access the EPC via the eNB that provides the E-UTRA function and the EPC via the en-gNB that provides the NR function, for example.

The S1 mode is used for 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, but each may be configured as a different mode. ..

In addition, N1 mode is a UE mode in which the UE can access 5GC via a 5G access network. Further, the N1 mode may be a UE mode capable of transmitting and receiving messages using the N1 interface. The N1 interface may be composed of an N1 interface and an Xn interface that connects radio base stations.

The UE in N1 mode can, for example, access 5GC via ng-eNB that provides the E-UTRA function and access 5GC via gNB that provides the NR function.

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

[1.2. Configuration of each device]
Hereinafter, the configuration of each device will be described. It should be noted that some or all of the following devices and some or all of the functions of each part of each device may operate on physical hardware, or logical hardware virtually configured on general-purpose hardware. It may be the one that operates on the 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, UE_A10 is composed of a control unit_A500, a transmission / reception unit_A520, and a storage unit_A540. The transmission / reception unit_A520 and the storage unit_A540 are connected to the control unit_A500 via a bus. An external antenna 410 is connected to the transmitter / receiver _A520.

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

The transmitter / receiver_A520 is a functional unit for UE_A10 to connect to the base stations (UTRAN_A20 and E-UTRAN_A80 and NG-RAN_A120) and / or wireless LAN access point (WLAN AN) in the access network and to connect to the access network. is there. In other words, the UE_A10 can be connected to a base station and / or an access point in the access network via an external antenna 410 connected to the transmitter / receiver_A520. Specifically, the UE_A10 transmits / receives user data and / or control information to / from a base station and / or an access point in the access network via an external antenna 410 connected to the transmission / reception unit_A520. Can be done.

The storage unit_A540 is a functional unit that stores programs and data required for each operation of UE_A10, and is composed 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, and the like included in control messages transmitted and received in the communication procedure described later.

[1.2.2. eNB / NR node]
Next, a device configuration example of eNB_A45 and NR node_A122 is shown in FIG. As shown in FIG. 6, the eNB_A45 and the NR node_A122 are composed of a control unit_B600, a network connection unit_B620, a transmission / reception unit_B630, and a 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. An external antenna 510 is connected to the transmitter / receiver _B630.

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

The network connection part_B620 is a functional part for eNB_A45 and NR node_A122 to connect with 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 the network connection part_B620. Specifically, the eNB_A45 and NR node_A122 can send and receive user data and / or control information to and from the AMF_A240 and / or UPF_A235 via the network connection portion_B620.

The transmission / reception unit_B630 is a functional unit for eNB_A45 and NR node_A122 to connect to UE_A10. In other words, the eNB_A45 and NR node_A122 can send and receive user data and / or control information to and from the UE_A10 via the transmission / reception unit_B630.

The storage unit_B640 is a functional unit that stores programs and data required for each operation of 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, and the like included in control messages transmitted and received in the communication procedure 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. In addition, the storage unit_C740 stores the context 642.

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

The network connection part_C720 is MME_A40 or AMF_A240, other MME_A40, AMF_240, SMF_A230, base stations in the access network (UTRAN_A20 and E-UTRAN_A80 and NG-RAN_A120) and / or wireless LAN access point (WLAN AN), UDM. , AUSF, a functional part for connecting to PCF. In other words, MME_A40 or AMF_A240 sends and receives user data and / or control information to and from base stations and / or access points, UDMs, AUSFs, and PCFs in the access network via network connection_C720. Can be done.

The storage unit_C740 is a functional unit that stores programs, data, etc. required for each operation of MME_A40 or AMF_A240. The storage unit_C740 is composed of, for example, a semiconductor memory, an HDD, an SSD, or the like. The storage unit_C740 stores identification information, control information, flags, parameters, and the like included in the control messages transmitted and received in the communication procedure 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. The 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, and eNB Address. , MME UE S1AP ID, eNB UE S1AP ID, NR node Address, NR node ID, WAG Address, WAG ID may be included. 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. The contexts stored for each bearer are EPS Bearer ID, TI, TFT, SGW F-TEID, PGW F-TEID, MME F-TEID, eNB Address, NR node Address, WAG Address, eNB ID, NR node. ID and WAG ID may be included.

In addition, there may be an N26 interface as an interface between the core networks between MME_A40 in EPC and AMF_A240 in 5GC. Here, the N26 interface is an optional interface for inter-system interworking between 5GS and EPS.

The N26 interface is an interface that enables transmission and reception for exchanging information on the mobility management status such as UE_A10 and the SM (Session Management) status between the UE and SMF between 5GS and EPS. It may be there. In addition, the N26 interface may be the interface required to enable seamless session continuity 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 is composed of a control unit_D800, a network connection unit_D820, and a storage unit_D840, respectively. The network connection unit _D820 and the storage unit _D840 are connected to the control unit _D800 via a bus. In addition, the storage unit_D840 stores the 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. To do.

The network connection part_D820 of SMF_A230 is a functional part for SMF_A230 to connect with AMF_A240, UPF_A235, UDM, and PCF. In other words, the SMF_A230 can send and receive user data and / or control information to and from the AMF_A240, UPF_A235, UDM, and PCF via the network connection_D820.

The storage unit_D840 of SMF_A230 is a functional unit that stores programs and data required for each operation of SMF_A230. The storage unit_D840 of the SMF_A230 is composed of, 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 the control messages transmitted and received in the communication procedure described later. 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. The context stored for each UE may include IMSI, ME Identity, MSISDN, RAT type. The context stored for each APN may include APN in use. The context stored for each APN may be stored for each Data Network Identifier. The context stored for each PDU session may include Assigned Session Type, IP Address (es), SGW F-TEID, PGW F-TEID, Default Bearer. The context stored for each bearer may include EPS Bearer ID, TFT, SGW F-TEID, PGW F-TEID.

[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, PGW_A30 or UPF_A235 is composed of a control unit_D800, a network connection unit_D820, and a storage unit_D840, respectively. The network connection unit _D820 and the storage unit _D840 are connected to the control unit _D800 via a bus. In addition, the storage unit_D840 stores the context 742.

The control unit_D800 of 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, PGW_A30 or UPF_A235 Realize various processing as a whole.

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 and E-UTRAN_A80 and NG-RAN_A120). It is a functional part to do. In other words, UPF_A235 is between the DN (ie DN_A5), SMF_A230, other UPF_A235, and the access network (ie UTRAN_A20 and E-UTRAN_A80 and NG-RAN_A120) via the network connection_D820. User data and / or control information can be sent and received.

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

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

The IMSI (International Mobile Subscriber Identity) is the permanent identification information of the subscriber (user), and is the identification information assigned to the user who uses the 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 status 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 in the network, and / or an EMM-DEREGISTERD state (unregistered state) in which UE_A10 is not registered in the network. Further, the EMM State / MM State may be an ECM-CONNECTED state in which the connection between UE_A10 and the core network is maintained, and / or an ECM-IDLE state in which the connection is released. The EMM State / MM State may be information that can distinguish between the state in which UE_A10 is registered in the EPC and the state in which it is registered in the NGC or 5GC.

GUTI (Globally Unique Temporary Identity) is temporary identification information of UE_A10. GUTI consists of MME_A40 / CPF_A140 / AMF_A240 identification information (GUMMEI (Globally Unique MME Identifier)) and UE_A10 identification information (M-TMSI (M-Temporary Mobile Subscriber Identity)) within the specific MME_A40 / CPF_A140 / AMF_A240. Will be done. ME Identity is UE_A10 or ME ID, and may be, for example, IMEI (International Mobile Equipment Identity) or IME ISV (IMEI Software Version). MSISDN represents the basic telephone number of UE_A10. The MSISDN stored by MME_A40 / CPF_A140 / AMF_A240 may be the information indicated by the storage unit of HSS_A50. The 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, the TEID (Tunnel Endpoint Identifier) of MME_A40 / CPF_A140 / AMF_A240, or both. May be good. Further, 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. Further, the IP address of SGW_A35 and the TEID of SGW_A35 may be stored independently. Further, the SGW F-TEID may be identification information for user data or identification information for control information.

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. Further, the PGW F-TEID may be identification information for user data or identification information for control information.

The eNB F-TEID is information that identifies eNB_A45. The eNB F-TEID may include the IP address of eNB_A45, the TEID of eNB_A45, or both of them. Further, 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 identification information for control information.

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

The APN may be identification information that identifies such a gateway, or identification information that identifies an external network such as a DN. When a plurality of gateways connecting the core network and the DN are arranged, there may be a plurality of gateways that can be selected by the APN. Furthermore, one gateway may be selected from a plurality of these 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 derived functions supported by UE_A10. MS Network Capability is information that includes one or more information required for SGSN_A42 for UE_A10 with GERAN_A25 and / or UTRAN_A20 functions. Access Restriction is registration information of access restriction. eNB Address is the IP address of eNB_A45. The MME UE S1AP ID is information that identifies UE_A10 in MME_A40 / CPF_A140 / AMF_A240. The eNB UE S1AP ID is information that identifies UE_A10 in eNB_A45.

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

Assigned Session Type is information indicating the type of PDU session. The Assigned Session Type may be the Assigned PDN Type. The type of PDU session can be IP or non-IP. In addition, if the type of PDU session is IP, it may further include information indicating the type of PDN assigned by the network. The Assigned Session Type may be IPv4, IPv6, or IPv4 v6.

Unless otherwise specified, IP Address is the IP address assigned to the UE. The IP address may be an IPv4 address, an IPv6 address, an IPv6 prefix, or an interface ID. If the Assigned Session Type indicates non-IP, the IP Address element may not be included.

The DN ID is identification information that distinguishes the core network_B190 from 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 that connects the core network_B190.

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. When 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 by the DN ID. Furthermore, one gateway may be selected from the plurality of gateways by another method using identification information other than the DN ID.

Furthermore, the DN ID may be information equal to or different from the APN. If the DN ID and the APN are different information, each device may manage the information indicating the correspondence between the DN ID and the APN, or may carry out a procedure for inquiring the APN using the DN ID. Alternatively, the procedure for inquiring the DN ID using the APN may be carried out.

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

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

Default Bearer is EPS bearer identification information that identifies the default bearer associated with a PDU session. The EPS bearer may be a logical communication path established between UE_A10 and PGW_A30 / UPGW_A130 / UPF_A235, or may be a communication path constituting a PDN connection / PDU session. Further, the EPS bearer may be a default bearer or a dedicated bearer. In addition, the EPS bearer may be configured to include an RB established between UE_A10 and a base station and / or access point in the access network. In addition, RBs and EPS bearers may have a one-to-one correspondence. Therefore, the RB identification information may be associated with the EPS bearer identification information on a one-to-one basis, or may be the same identification information. The RB may be SRB and / or CRB, or may be DRB. The Default Bearer may be information acquired by UE_A10 and / or SGW_A35 and / or PGW_A30 / UPGW_A130 / SMF_A230 / UPF_A235 from the core network when the PDU session is established. The default bearer is an EPS bearer that is first established in a PDN connection / PDU session, and is an EPS bearer that can be established only once in one PDN connection / PDU session. The default bearer may be an EPS bearer that can be used to communicate user data that is not associated with a TFT. A decadeted bearer is an EPS bearer that is established after the default bearer is established in a PDN connection / PDU session, and is an EPS bearer that can be established multiple times in one PDN connection / PDU session. is there. A decadeted bearer is an EPS bearer that can be used to communicate user data associated with a TFT.

User Identity is information that identifies the subscriber. The User Identity may be IMSI or MSISDN. Further, the 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 in eNB_A45. MME Address is the IP address of MME_A40 / CPF_A140 / AMF_A240. The MME ID is information that identifies MME_A40 / CPF_A140 / AMF_A240. NR node Address is the IP address of NR node_A122. The NR node ID is information that identifies NR node_A122. WAG Address is the IP address of WAG. The WAG ID is information that identifies the WAG.

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

The SSC mode indicates the mode of Session and Service Continuity supported by the system and / or each device in 5GC. More specifically, it may be a mode indicating the types of service session continuation supported by the PDU session established between UE_A10 and the anchor point). Here, the anchor point may be UPGW or UPF_A235. The SSC mode may be a mode indicating the type of service session continuation set for each PDU session. Further, the SSC mode may be composed of three modes, SSC mode 1, SSC mode 2, and SSC mode 3. SSC mode is associated with the anchor point and cannot be changed while the PDU session is established.

Further, SSC mode 1 in the present embodiment is a service session continuation mode in which the same UPF is maintained as an anchor point regardless of access technologies such as RAT (Radio Access Technology) and cells used when UE_A10 connects to the network. 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 when UE_A10 mobility occurs.

Further, when SSC mode 2 in the present embodiment includes an anchor point associated with one SSC mode 2 in the PDU session, the service session continuation in which the PDU session is released first and then the PDU session is established continuously. The mode. More specifically, SSC mode2 is a mode in which when an anchor point relocation occurs, the PDU session is deleted once and then a new PDU session is established.

Furthermore, SSC mode 2 is a service session continuation mode in which the same UPF is maintained as an anchor point only within the serving area of the UPF. More specifically, SSC mode 2 may be a mode that realizes service session continuation without changing the UPF used by the established PDU session as long as UE_A10 is within the serving area of the UPF. Furthermore, SSC mode 2 is a mode that realizes service session continuation by changing the UPF used by the established PDU session when the mobility of UE_A10 occurs, such as leaving the serving area of the UPF. Good.

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

Further, SSC mode 3 in the present embodiment is a service session continuation mode in which a PDU session can be established between a new anchor point and the UE for the same DN without releasing the PDU session between the UE and the anchor point. is there.

In addition, SSC mode 3 is a new PDU session established between UE_A10 and UPF, and / or a new PDU session via a new UPF for the same DN before disconnecting. Alternatively, it is a mode of service session continuation that allows the establishment of a communication path. In addition, SSC mode 3 may be a service session continuation mode that allows UE_A10 to be multihoming.

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

Here, if each device establishes a new PDU session and / or communication path, the selection of the new UPF may be carried out by the network, and the new UPF is where UE_A10 connects to the network. It may be the most suitable UPF. In addition, if the UPF used by multiple PDU sessions and / or PDU sessions is enabled, UE_A10 will immediately address the newly established PDU session for application and / or flow communication. It may be carried out based on the completion of communication.

[1.3. Explanation of initial procedure]
Next, before explaining the detailed procedure of the initial procedure in the present embodiment, in order to avoid duplicate explanation, the terms specific to the present embodiment and the main identification information used for each procedure will be described in advance.

In the present embodiment, the network refers to at least a part of access network_A20 / 80, access network_B80 / 120, core network_A90, core network_B190, DN_A5, and PDN_A6. 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 are referred to as a network or network device. You may call it. That is, the fact that the network executes the transmission / reception and / or procedure of the message means that the device (network device) in the network executes the transmission / reception and / or procedure of the message.

The session management (SM) message (also referred to as NAS (Non-Access-Stratum) SM message or SM message) in the present embodiment is a procedure for SM (also referred to as a session management procedure or SM procedure). It may be a NAS message used in the above, and may be a control message sent and received between UE_A10 and SMF_A230 via AMF_A240. Further, 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, and the like. You may. In addition, the procedure for SM may include a PDU session establishment procedure, a PDU session change procedure, and the like.

Of the SM messages, the message transmitted 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 that can be represented by the position information of UE_A10 managed by the core network, and may be composed of, for example, one or more cells. Further, the TA may be a range in which a control message such as a paging message is broadcast, or a range in which UE_A10 can move without performing a handover procedure.

The TA list in this embodiment is a list including one or more TAs assigned to UE_A10 by the network. Note that UE_A10 may be able to move without executing the registration procedure while moving within one or more TAs included in the TA list. In other words, the TA list may be a set of information indicating the areas that UE_A10 can move to without performing the registration procedure.

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

The NSI (Network Slice Instance) in the present embodiment is an entity of a network slice (Network Slice) composed of one or more in the core network_B190. Further, the NSI in the present embodiment may be composed of a virtual NF (Network Function) generated by using the NST (Network Slice Template). Here, NST is a logical expression of one or more NFs (Network Functions) associated with a resource request for providing a required communication service or capability. That is, the NSI may be an aggregate in the core network_B190 composed of a plurality of NFs. In addition, NSI may be a logical network configured to separate user data delivered by services and the like. At least one or more NFs may be configured in the network slice. The NF configured in the network slice may or may not be a device shared with other network slices. UE_A10 and / or devices in the network include NSSAI and / or S-NSSAI and / or UE usage type and / or one or more network slice type IDs and / or one or more NS IDs, etc. It 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 composed of SST only or both SST and SD. Here, SST is information indicating the operation of the network slice expected in terms of function and service. Further, SD may be information that complements SST when selecting one NSI from a plurality of NSIs represented by SST. S-NSSAI may be information specific to each PLMN (Public Land Mobile Network), standard information shared among PLMNs, or information specific to a telecommunications 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 information specific to a telecommunications carrier (Non Standard Value) that differs for each PLMN. You may.

In addition, the network may store one or more S-NSSAI in the registration information of UE_A10 as the default S-NSSAI.

NSSAI (Single Network Slice Selection Assistance information) in this embodiment is a collection of S-NSSAI. Each S-NSSAI contained in NSSAI is information that assists the access network or core network in selecting NSI. UE_A10 may store NSSAI permitted from the network for each PLMN. Also, NSSAI may be the 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, the operator A may develop a NW slice common to the operator B described later.

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

The LADN (Local Area Data Network) in the present embodiment is a DN to which the UE can connect only in a specific place, 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 available to the UE. LADN information may include LADN DNN and LADN service area information. The LADN DNN may be information indicating LADN, information indicating a DN treated as LADN, or a DNN used when establishing a PDU session for LADN. Further, the LADN service area information may be information indicating the LADN service area. Further, LADN service area information may be provided as a set of tracking areas or as a TAI (Tracking area identity) list. The LADN service area may be an area where a PDU session for LADN can be established, or an area where connection to LADN is possible.

The PDU session for LADN in this embodiment is a PDU session associated with the DNN associated with LADN. The PDU session for LADN may be a PDU session established for LADN. In other words, it may be a PDU session established between the UE and LADN, or it may be a PDU session used for user data communication between the UE and LADN. 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 the present 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 (Virtual Network) on 5GS that supports 5G LAN type services.

The 5G VN group (5G Virtual Network (VN) Group) in the present embodiment is a group composed of a plurality of UEs used for private communication for a 5G LAN type service.

Information about the 5G VN group may include the 5G VN group ID, 5G VN group membership, and 5G VN group data, and 5GS will use this information to support the management of the 5G VN group. To do. Here, the 5G VN group ID may be an External Group ID and an Internal Group ID used to identify the 5G VN group. As a 5G VN 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 PDU session type, DNN and S-NSSAI, and 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. Further, the DNN and the 5G VN group, which are the first identification information, may be associated with each other on a one-to-many basis or a many-to-one basis. In other words, a plurality of 5G VN groups may be associated with one DNN, or a plurality of DNNs may be associated with one 5G VN group.

The PDU session for 5G VN Group in the present embodiment is a PDU session by DNN associated with the 5G VN group. The PDU session for the 5G VN group may be a PDU session in which UE_A10 is established using the DNN associated with the 5G VN group to connect (access or join) 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 established the PDU session for the 5G VN group communicates user data with the UEs of other members accessing the same 5G VN group using the PDU session for the 5G VN group. You may be able to do it.

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 IPv4 v6 type. The non-IP type may be, for example, an Ethernet type, and any mode (SSC mode 1, SSC mode 2, or SSC mode 3) for continuing session service is set. You may be.

The first state in the present embodiment is a state in which each device has completed the registration procedure and the PDU session establishment procedure, and UE_A10 and / or each device has 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 in the network (RM-REGISTERED state) by completing the registration procedure, and when the PDU session establishment procedure is completed, UE_A10 is PDU from the network. The session establishment acceptance message may be received.

The first identification information in the present embodiment may be a DNN (Data Network Name) associated with the 5G VN group. Here, the DNN, which is the first identification information, and the 5G VN group may be associated with each other 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.

Since UE_A10 accesses the 5G VN group, the first identification information may be transmitted / provided to the network in the PDU session establishment procedure. More specifically, UE_A10 sends the NAS message for requesting the establishment of the PDU session including the first identification information, and receives the PDU session establishment acceptance message based on the first identification information from the core network. This may establish a PDU session for the 5G VN group.

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

Note that the DNN used in the PDU session that supports EPS interwork 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, the APN associated with the DNN indicated by the first identification information may not be present.

The second identification information in this embodiment may be information indicating a set of EPS (Evolved Packet System) bearer contexts for a PDU session (Mapped EPS bearer contexts IE). Here, the second identification information may be an information element assigned by the SMF when the UE establishes a PDU session in 5GS. Further, 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 transferred to EPS by handover.

The second identification information may be the identification information included in the PDU session establishment acceptance message when the PDU session established by UE_A10 in the PDU session establishment procedure supports interworking with EPS. Conversely, if the second identity is not included in the PSU session establishment acceptance message, it may mean that the established PDU session does not support interworking with EPS and is handed over to EPS. It doesn't have to be transferable.

In addition, if the PDU session established by UE_A10 in 5GS is a LADN PDU session, or if it is a multi-homed IPv6 PDU session, or for a 5G VN group. If it is a PDU session, the SMF does not have to assign a second identity.

For example, the PDU session for the 5GN VN group may be the PDU session established when UE_A10 and / or the core network B_199 selects and uses the DNN associated with the 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 identity, and the PDU session for the established 5G VN group , The second identification information may not be assigned.

Next, the initial procedure in this embodiment will be described with reference to FIG. Hereinafter, the initial procedure is also referred to as this procedure, and this procedure includes a registration procedure (Registration procedure), a UE-led PDU session establishment procedure (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, when each device executes the registration procedure (S900), UE_A10 transitions to the state registered in the network (RM-REGISTERED state). Next, each device executes the PDU session establishment procedure (S902), so that UE_A10 establishes a PDU session with DN_A5, which provides the PDU connection service, via the core network_B190, and between each device. Transitions to the first state (S904). The PDU session established here may be a PDU session for the 5G VN group, or may be a PDU session based on the 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 to this. That is, there may be a UPF (UPF_C239) different from the UPF_A235 between the UPF_A235 and the access network. At this time, this PDU session will be established via the access network, UPF_C239, UPF_A235. Next, each device in the first state may execute the handover procedure at any time (S906). Here, the handover procedure may be a UE-led or network-led 5GS-to-EPS handover procedure between systems. Further, the 5GS to EPS handover procedure between systems may be a procedure for transferring any PDU session established in the first state from 5GS to EPS.

In addition, each device may exchange various ability information and / or various request information of each device in the registration procedure and / or the PDU session establishment procedure and / or the hand-bar procedure. In addition, when each device exchanges various information and / or negotiates various requests in the registration procedure, exchanges various information and / or negotiates various requests in the PDU session establishment procedure and / or handover procedure. It may or may not be. In addition, if each device does not exchange various information and / or negotiate various requests in the registration procedure, exchange various information and / or negotiate various requests in the PDU session establishment procedure and / or handover procedure. It may be carried out. In addition, even if each device exchanges various information and / or negotiates various requests in the registration procedure, exchanges various information and / or negotiates various requests in the PDU session establishment procedure and / or handover procedure. You may.

In addition, each device may execute the PDU session establishment procedure in the registration procedure or after the registration procedure is completed. Also, if 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 acceptance message may be included in the registration acceptance message and sent / received. The PDU session establishment completion message may be included in the registration completion message and sent / received, and the PDU session establishment rejection message may be included in the registration rejection message and sent / received. Further, when the PDU session establishment procedure is executed in the registration procedure, each device may establish a PDU session based on the completion of the registration procedure, or the PDU session is established between the devices. You may transition.

In addition, each device involved in this procedure sends and receives one or more identification information included in each control message by transmitting and receiving each control message described in this procedure, and stores each transmitted and received identification information as a context. May be good.

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

In addition, this procedure updates the location registration information of UE_A10 in the network and / or periodically notifies the network of the status of UE_A10 from UE_A10 and / or updates specific parameters regarding UE_A10 in the network. It may be the procedure of.

UE_A10 may start this procedure when it has mobility across TAs. In other words, UE_A10 may start this procedure when it moves to a TA different from the TA shown in the held TA list. In addition, UE_A10 may start this procedure when the running timer expires. In addition, UE_A10 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 the PDU session. In addition, UE_A10 may initiate this procedure if there is a change in capability information and / or preferences regarding UE_A10's PDU session establishment. In addition, UE_A10 may initiate this procedure on a regular basis. UE_A10 is not limited to these, and this procedure can be executed at any timing as long as the PDU session is established.

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

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

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

The registration request message is a NAS (Non-Access-Stratum) message sent and received on the N1 interface. The RRC message is a control message sent and received between UE_A10 and NR node_A122 and / or ng-eNB. In addition, 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.

In addition, UE_A10 may send a registration request message for each NSI when there are multiple NSIs requesting registration, or may send multiple registration request messages by including them in one or more RRC messages. Good. Further, the above-mentioned plurality of registration request messages may be included in one or more RRC messages and transmitted as one registration request message.

When AMF_A240 receives a registration request message and / or a control message different from the registration request message, it executes the first condition determination. The first conditional determination is for determining whether or not AMF_A240 accepts the request of UE_A10. In the first condition determination, AMF_A240 determines whether the first condition determination is true or false. AMF_A240 initiates procedure (A) during this procedure if the first condition determination is true (ie, if the network accepts the request for UE_A10) and if the first condition determination is false (ie). , If the network does not accept the request of UE_A10), start the procedure (B) during this procedure.

Hereinafter, the steps when the first condition determination is true, that is, each step of the procedure (A) in this procedure will be described. AMF_A240 executes the fourth condition determination and starts the procedure (A) during this procedure. The fourth condition determination is for determining whether or not AMF_A240 sends and receives SM messages to and from SMF_A230. In other words, the fourth condition determination may determine whether or not AMF_A240 is in the process of performing the PDU session establishment procedure. AMF_A240 selects SMF_A230 and sends and receives SM messages to and from the selected SMF_A230 when the fourth condition determination is true (that is, when AMF_A240 sends and receives SM messages to and from SMF_A230). If the fourth condition determination is false (that is, AMF_A240 does not send or receive SM messages to or from SMF_A230), omit them (S1006). When AMF_A240 receives an SM message indicating refusal from SMF_A230, it may cancel the procedure (A) during this procedure and start the procedure (B) during this procedure.

In addition, AMF_A240 sends a Registration Accept message to UE_A10 via NR node_A122 based on the receipt of the registration request message from UE_A10 and / or the completion of sending and receiving SM messages to and from SMF_A230. (S1008). For example, if the fourth condition determination is true, AMF_A240 may send a registration acceptance message based on the receipt of the registration request message from UE_A10. Further, if the fourth condition determination is false, AMF_A240 may send a registration acceptance message based on the completion of transmission / reception of the SM message with SMF_A230. Here, the registration acceptance message may be sent as a response message to the registration request message. The registration acceptance message is a NAS message sent and received on the N1 interface. For example, AMF_A240 sends an N2 interface control message to the NR node_A122, and the NR node_A122 that receives this is an RRC message to the UE_A10. You may include it in and send it.

Further, if the fourth condition determination is true, the AMF_A240 may send the registration acceptance message including the SM message (eg, PDU session establishment acceptance message), or together with the registration acceptance message, the SM message (eg, PDU). A session establishment acceptance message) may be sent. This transmission method may be executed when the SM message (for example, the 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 the SM message (for example, the 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 SM has been accepted by performing such a transmission method.

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

UE_A10 then sends a Registration Complete message to AMF_A240 based on the receipt of the registration acceptance message (S1010). When UE_A10 receives an SM message such as a PDU session establishment acceptance message, it may send the registration completion message including the SM message such as the PDU session establishment completion message, or by including the SM message. , May indicate that the procedure for SM is completed. Here, the registration completion message may be sent as a response message to the registration acceptance message. 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 the RRC message, and NR node_A122 that receives this is sent to AMF_A240 on the N2 interface. It may be sent as a control message.

AMF_A240 receives a registration completion message (S1010). In addition, each device completes the procedure (A) in this procedure based on the transmission / 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 described. AMF_A240 initiates procedure (B) during this procedure by sending a Registration Reject message to UE_A10 via NR node_A122 (S1012). Here, the registration refusal message may be sent as a response message to the registration request message. The registration refusal message is a NAS message sent and received on the N1 interface. For example, AMF_A240 sends an N2 interface control message to the NR node_A122, and the NR node_A122 that receives this is an RRC message to the UE_A10. You may include it in and send it. Further, the registration refusal message transmitted by AMF_A240 is not limited to this as long as it is a message that rejects the request of UE_A10.

The procedure (B) during this procedure may be started when the procedure (A) during this procedure is canceled. In the procedure (A), if the fourth condition determination is true, AMF_A240 may send the registration refusal message including an SM message indicating refusal such as a PDU session establishment refusal message, or reject the registration. The inclusion of the meaning SM message may indicate that the procedure for SM has been rejected. In that case, UE_A10 may further receive an SM message indicating rejection such as a PDU session establishment refusal message, or may recognize that the procedure for SM has been rejected.

Further, UE_A10 may recognize that the request of UE_A10 has been rejected by receiving the registration refusal message or by not receiving the registration acceptance message. Each device completes the procedure (B) during this procedure based on the transmission and reception of the registration refusal message.

Each device completes this procedure (registration procedure) based on the completion of procedure (A) or (B) during this procedure. In addition, each device may transition to the state in which UE_A10 is registered in the network (RM_REGISTERED state) based on the completion of the procedure (A) during this procedure, or the procedure (B) during this procedure. UE_A10 may remain unregistered in the network (RM_DEREGISTERED state) based on the completion of. Further, 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 the PDU session.

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

Further, the first condition determination may be executed based on the identification information and / or the subscriber information included in the registration request message and / or the operator policy. For example, the first condition determination may be true if the network allows the request for UE_A10. Further, the first condition determination may be false if the network does not allow the request of UE_A10. Further, the first condition determination may be true if the network to which UE_A10 is registered and / or the device in the network supports the function required by UE_A10, and false if it does not support it. Good. Further, the first condition determination may be true if the network determines that it is in a congested state, and may be false if it is determined that it is not in a congested state. The condition for determining the truth of the first condition determination does not have to be limited to the above-mentioned condition.

Further, the fourth condition determination may be executed based on whether or not AMF_A240 has received the SM, and may be executed based on whether or not the registration request message includes the SM message. For example, the fourth condition determination may be true if AMF_A240 receives SM and / or if the registration request message contains an SM message, if AMF_A240 does not receive SM, and / Or may be false if the registration request message does not contain an SM message. The condition for determining the truth of the fourth condition determination does not have to be limited to the above-mentioned condition.

[1.3.2. Outline of PDU session establishment procedure]
Next, the outline of the PDU session establishment procedure performed to establish the PDU session for DN_A5 will be described. Hereinafter, the PDU session establishment procedure is also referred to as this procedure. This procedure is a procedure for each device to establish a PDU session. In addition, each device may execute this procedure in a state where the registration procedure is completed, or may execute this procedure in the registration procedure. Further, each device may start the main procedure in the registered state, or may start the main procedure at an arbitrary timing after the registration procedure. In addition, each device may establish a PDU session based on the completion of the PDU session establishment procedure. Further, each device may establish a plurality of PDU sessions by executing this procedure a plurality of times.

[1.3.2.1. Example of PDU session establishment procedure]
An example of the procedure for executing the PDU session establishment procedure will be described with reference to FIG. Each step of this procedure will be described below. First, UE_A10 starts the PDU session establishment procedure by sending a PDU session establishment request (PDU Session Establishment Request) message to the core network_B via the access network_B (S1100).

Specifically, UE_A10 uses the N1 interface to send a PDU session establishment request message to AMF_A240 in core network_B190 via NR node_A122 (S1100). AMF_A receives the PDU session establishment request message and executes the third condition determination. The third condition determination is for determining whether or not AMF_A accepts the request of UE_A10. In the third condition determination, AMF_A determines whether the fifth condition determination is true or false. If the third condition determination is true, the core network_B starts processing # 1 in the core network (S1101), and if the third condition determination is false, the procedure (B) in this procedure is performed. Start. The step when the third condition determination is false will be described later. Here, the process # 1 in the core network may be SMF selection by AMF_A in the core network_B190 and / or transmission / reception of a PDU session establishment request message between AMF_A and SMF_A.

Core network_B190 starts processing # 1 in the core network. In process # 1 in the core network, AMF_A240 selects SMF_A230 as the routing destination NF for the PDU session establishment request message, and uses the N11 interface to send or forward the PDU session establishment request message to the selected SMF_A230. May be good. Here, AMF_A240 may select the routing destination SMF_A230 based on the information contained in the PDU session establishment request message. More specifically, the AMF_A240 is the identification information and / or subscriber information acquired based on the reception of the PDU session establishment request message, and / or the capability information of the network, and / or the operator policy, and / or the network. The routing destination SMF_A230 may be selected based on the state and / or the context already held by AMF_A240.

The PDU session establishment request message may be a NAS message. Further, the PDU session establishment request message may be any message that requests the establishment of the 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 the PDU session or the PDU session establishment request message, and by including this identification information, the request of UE_A10 can be made. May be shown.

In addition, UE_A10 requests the establishment of a PDU session for the 5G VN group by sending the first identification information in the NAS message for requesting the establishment of the PDU session or the PDU session establishment request message. It may indicate the 5G VN group to which the PDU session belongs, as requested by UE_A10, or it may indicate the 5G VN group to which the PDU session will belong.

In addition, UE_A10 determines whether or not to include the first identification information in the NAS message for requesting the establishment of the PDU session or the PDU session establishment request message, the capability information of UE_A10, and / or the policy such as the UE policy. And / or may be determined based on UE_A10 preferences and / or application (upper layer). The UE_A10 is not limited to determining whether to include the first identification information in the NAS message for requesting the establishment of the PDU session or the PDU session establishment request message.

SMF_A230 in core network_B190 receives the PDU session establishment request message and executes the third condition determination. The third condition determination is for determining whether or not SMF_A230 accepts the request of UE_A10. In the third condition determination, SMF_A230 determines whether the third condition determination is true or false. SMF_A230 starts the procedure (A) in this procedure when the third condition judgment is true, and starts the procedure (B) in this procedure when the third condition judgment is false. The step when the third condition determination is false will be described later.

Hereinafter, the steps when the third condition determination is true, that is, each step of the procedure (A) in this procedure will be described. SMF_A230 selects UPF_A235 to establish the PDU session and executes the eleventh condition determination.

Here, the eleventh condition determination is for determining whether or not each device executes the process # 2 in the core network. Here, process # 2 in the core network is the start and / or execution of the PDU session establishment authentication procedure by each device, and / or the session establishment request message between SMF_A and UPF_A in the core network_B190. And / or sending and receiving Session Establishment response messages, etc. may be included (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 approval procedure when the eleventh condition determination is true, and omits the PDU session establishment authentication approval approval procedure when the eleventh condition determination is false. The details of the PDU session establishment authentication approval procedure for 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 completion of the eleventh condition determination and / or the PDU session establishment authentication approval procedure, and starts the procedure (A) during this procedure. To do. In addition, SMF_A230 may start the procedure (B) in this procedure without starting the procedure (A) in this procedure based on the completion of the PDU session establishment authentication approval procedure.

Here, the SMF_A230 is the identification information acquired based on the reception of the PDU session establishment request message, and / or the network capability information and / or the subscriber information, and / or the operator policy, and / or the network status. And / or one or more UPF_A235s may be selected based on the context already held by SMF_A230. When a plurality of UPF_A235s are selected, SMF_A230 may send a session establishment request message to each UPF_A235.

UPF_A235 receives the session establishment request message and creates a context for the PDU session. In addition, UPF_A235 receives a session establishment request message and / or sends a session establishment response message to SMF_A230 based on creating a context for the PDU session. In addition, SMF_A230 receives a session establishment response message. 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_A230 may assign an address to UE_A10 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. Note that SMF_A230 may assign the address assigned to UE_A10 during the PDU session establishment procedure, or may perform it after the PDU session establishment procedure is completed.

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

In addition, SMF_A230 may include the assigned address in the PDU session establishment acceptance message and send it to UE_A10 based on the completion of address assignment of the address assigned to UE_A10, or send it to UE_A10 after the PDU session establishment procedure is completed. You may.

SMF_A230 sends to UE_A10 via AMF_A240 based on the receipt 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 assigned to UE_A10. Send a PDU session establish accept message (S1110).

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

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

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

Here, the PDU session establishment acceptance message transmitted by SMF_A230 and received by UE_A10 may contain either the first identification information or the second identification information, or any of these identification information. May indicate that the request for UE_A10 has been accepted by including. For example, if SMF_A230 includes the first identification information in the PDU session establishment acceptance message, it is not necessary to include the second identification information, and conversely, SMF_A230 includes the second identification information in the PDU session establishment acceptance message. When the identification information is included, it is not necessary to include the first identification information.

Furthermore, if SMF_A230 includes the first identity in the PDU session establishment acceptance message and not the second identity, UE_A10 may indicate that the establishment of the PDU session for the 5G VN group has been accepted. Alternatively, this PDU session may indicate that intersystem interworking with EPS is not supported and handover to EPS is not allowed, and UE_A10 may recognize these. Conversely, if SMF_A230 includes the second identity in the PDU session establishment acceptance message and not the first identity, then this PDU session supports intersystem interworking with EPS and EPS. It may indicate that handover to is allowed, and that this PDU session may indicate that it is not a PDU session for a 5G VN group, and UE_A10 may recognize these. ..

Here, when SMF_A230 includes the DNN in the PDU session establishment acceptance message as the first identification information, SMF_A230 does not have 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 the second identification information in the PDU session establishment acceptance message.

In other words, a PDU session for a 5G VN group does not support intersystem interworking with EPS and may not allow handover to EPS, or conversely, intersystem with EPS. A PDU session that supports interworking and is allowed to hand over to EPS does not have to be a PDU session for a 5G VN group.

In addition, SMF_A230 indicates which of the first identification information and / or the second identification information is included in the PDU session establishment acceptance message, the received identification information, and / or the network capability information. And / or may be determined based on policies such as operator policies and / or network conditions and / or user subscription information. It should be noted that the decision by SMF_A230 whether to include either or both of these identification information in the PDU session establishment acceptance message is not limited to these.

Further, the first identification information may be the same DNN included in the NAS message for requesting the establishment of the PDU session or the PDU session establishment request message by UE_A10 described above. Alternatively, the first identification information is a 5G VN selected by AMF or another core network device regardless of whether UE_A10 is included in the NAS message for requesting the establishment of a PDU session or the PDU session establishment request message. It may be a DNN associated with a group.

UE_A10 then sends 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). In addition, SMF_A230 receives the PDU session establishment completion message and executes the second condition determination.

Specifically, UE_A10 uses the N1 interface to send a PDU session establishment completion message to AMF_A240, and AMF_A240, which receives the PDU session establishment completion message, sends a PDU session establishment completion message to SMF_A230 using the N11 interface. ..

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 a response message to the PDU session establishment acceptance message, and is not limited to this, and may be a message indicating that the PDU session establishment procedure is completed.

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

Each device is in the process of this procedure based on sending and receiving PDU session establishment completion messages, / or sending and receiving session change response messages, and / or sending and receiving session establishment response messages, and / or sending and receiving RA (Router Advertisement). Complete the procedure of (A).

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

Specifically, SMF_A230 uses the N11 interface to send a PDU session establishment rejection message to AMF_A240, and AMF_A240 that receives the PDU session establishment request message sends a PDU session establishment rejection message to UE_A10 using the N1 interface. ..

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

[1.3.3. Outline of Handover Procedure]
Next, the outline of the handover procedure will be described. Hereinafter, the handover procedure is also referred to as this procedure. This procedure may be a procedure for handover between systems from 5GS to EPS led by UE or network. In addition, the 5GS-to-EPS system-to-system handover procedure may be a procedure for transferring an established PDU session from 5GS to EPS, in order to transfer a PDU session that supports interwork with EPS to EPS. It may be the procedure of.

If the UE receives a second identity 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 identity in the PDU session establishment procedure, the established PDU session may not be able to be transferred to the EPS.

Here, the PDU session that supports interwork between the systems with EPS can be transferred to EPS based on the handover procedure. Conversely, this procedure will not be performed in a PDU session that does not support interworking with EPS. In other words, the UE and each device shall 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, the PDU session for the 5GVN group must not be transferred to the EPC. Furthermore, if UE_A10 has established multiple PDU sessions, only PDU sessions that support inter-system interaction with EPS may be transferred to EPS by this procedure.

In addition, this procedure may be composed of different procedures in which different devices are started based on the presence / absence of the N26 interface between the MME and the AMF and the state of each device of the UE and the network. For example, in the case of a handover from 5GS to EPS when there is an N26 interface, it may be a network-led procedure initiated by NG-RAN. Also, for example, in the case of moving from 5GS to EPS, if there is an N26 interface and there is idle mode mobility (Idle Mode Mobility), or if there is no N26 interface, the EPS at the destination led by the UE It may be initiated by the Tracking Area Update procedure or the 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 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 an example when this procedure should not be performed. Below, when there is an N26 interface and there is a handover from 5GS to EPS, and when there is an N26 interface and there is an idle mode mobility from 5GS to EPS (Idle Mode Mobility), or when there is no N26 interface, respectively. The UE and the behavior of each device will be described.

First, there is an N26 interface, and the procedure for handing over from 5GS to EPS is that NG-RAN via a PDU session for the 5G VN group established in the first state hands over to E-UTRAN. May be initiated by determining that is required. Next, the NG-RAN that decides to execute the handover sends a handover request to the AMF, and the AMF sends the SMF an EPS for the PDU session indicated by the second identification information based on the reception of the handover request. Send a message (Nsmf_PDUSession_Context Request) containing information indicating a set of bearer contexts (mapped EPS Bearer Contexts).

Here, the PDU session for the 5G VN group to be handed over is the information (mapped EPS Bearer) indicating the set of EPS bearer contexts for the PDU session indicated by the second identification information in the PDU session establishment procedure. Since Contexts) are not assigned by SMF and do not support interworking with EPS, the above NG-RAN may terminate this procedure without deciding the handover to EPS. After determining the handover and transmitting the handover request to the AMF, the AMF receiving the handover request may end the procedure without sending a message to the SMF.

Next, if there is an N26 interface and you want to move from 5GS to EPS in idle mode (Idle Mode Mobility), or if you do not have an N26 interface, the tracking area update procedure (Tracking Area Update) in the destination EPS led by UE_A10 ( It may be started by the TAU) procedure) or the Initial Attach procedure.

Here, the PDU session for the 5G VN group to be handed over is the information (mapped EPS Bearer) indicating the set of EPS bearer contexts for the PDU session indicated by the second identification information in the PDU session establishment procedure. Since Contexts) is not assigned by SMF and does not support interworking with EPS, the UE does not execute the tracking area update procedure or initial attach procedure in the destination EPS, even if this procedure is completed. Good.

From the above, the PDU session for the 5G VN group is not assigned information (mapped EPS Bearer Contexts) indicating the set of EPS bearer contexts for the PDU session from SMF, and supports interworking with EPS. Therefore, at the discretion of the UE or each device, the procedure for transferring the PDU session from 5GS to EPS does not have to be performed. In other words, in a system-to-system change from N1 mode to S1 mode, UE_A10 must not transfer the PDU session for the 5G VN group to EPS.

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

[2. Modification example]
The program that operates in the apparatus according to the present invention may be a program that controls the Central Processing Unit (CPU) or the like to operate the computer so as to realize the functions of the embodiments according to the present invention. The program or the information handled by the program is temporarily stored in a volatile memory such as Random Access Memory (RAM), a non-volatile memory such as a flash memory, a Hard Disk Drive (HDD), or another storage device system.

A computer-readable recording medium may be used to record a program for realizing the functions of the embodiments according to the present invention. It may be realized by loading the program recorded on this recording medium into a computer system and executing it. The "computer system" as used herein is a computer system built into a device, and includes hardware such as an operating system and peripheral devices. The "computer-readable recording medium" is a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a medium that dynamically holds a program for a short time, or another recording medium that can be read by a computer. Is also good.

Further, each functional block or feature of the device used in the above-described embodiment can be implemented or executed in an electric circuit, for example, an integrated circuit or a plurality of integrated circuits. Electrical circuits designed to perform the functions described herein are general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or others. Programmable logic devices, discrete gate or transistor logic, discrete hardware components, or a combination thereof may be included. The general purpose processor may be a microprocessor, a conventional processor, a controller, a microcontroller, or a state machine. The electric circuit described above may be composed of a digital circuit or an analog circuit. In addition, when an integrated circuit technology that replaces the current integrated circuit appears due to advances in semiconductor technology, one or more aspects of the present invention can also use a new integrated circuit according to the technology.

The invention of the present application is not limited to the above-described embodiment. In the embodiment, an example of the device has been described, but the present invention is not limited to this, and the present invention is not limited to this, and a stationary or non-movable electronic device installed indoors or outdoors, for example, an AV device or a kitchen device. , Cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other terminal devices or communication devices such as living equipment.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within a range not deviating from the gist of the present invention are also included. Further, the present invention can be variously modified within the scope of the claims, and the technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is done. In addition, the elements described in each of the above-described embodiments include a configuration in which elements having the same effect are replaced with each other.

1 Mobile communication system
5 DN_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)

UE (User Equipment)
In the PDU (Protocol Data Unit) session establishment procedure
The transmitter / receiver that receives the PDU session establishment acceptance message from the core network,
Equipped with a control unit to establish 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 contain 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, the UE does not transfer the PDU session to EPS.
UE characterized by that. UE (User Equipment) communication control method
In the PDU (Protocol Data Unit) session establishment procedure
The step of receiving the PDU session establishment acceptance message from the core network,
Has a step to establish a PDU session and
The PDU session is a PDU session associated with a 5G VN (Virtual Network) group.
The PDU session establishment acceptance message does not contain 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, the UE does not transfer the PDU session to EPS.
UE communication control method characterized by that.

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