Emergency network division method

Abstract

This network node includes a control unit and a communication unit. The communication unit is configured so as to receive, during an emergency, a message requesting that a terminal device use a first network slice, said first network slice being a network slice that is allocated for emergency use. The control unit is configured so as to determine, during the emergency, whether the terminal device is registered for emergency use, and establish a PDU session for the terminal device via the first network slice if the terminal device is registered for emergency use, or reject the request if the terminal device is not registered for emergency use.

Description

Emergency Network Isolation Methods CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from Japanese Patent Application No. 2024-041939, filed on March 18, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to an emergency network separation method, and more particularly to an emergency network separation method for separating a network between a terminal device registered for normal use and a terminal device registered for emergency use when an emergency such as a disaster occurs.

[0003] The Third Generation Partnership Project (3GPP (registered trademark)) defines network slicing, a technology that virtually divides a network and controls traffic at a fine granularity for each application by implementing bandwidth restrictions and priority control.

[0004] A virtually divided network is called a network slice, and an identifier called S-NSSAI (Single-Network Slice Selection Assistance Information) is assigned to the network slice.

[0005] 3GPP TS 23.501 V18.4.0 (2023-12)

[0006] Non-Patent Document 1 describes the provision of an emergency service, in which, when an emergency such as a disaster occurs, an Internet Protocol Multimedia Subsystem (IMS) service session is prioritized for an emergency registered UE over a normally registered UE.

[0007] Non-Patent Document 1 merely describes that in the event of an emergency, priority is given to an IMS service session for a UE registered for emergency use, but does not describe separating the network between a UE registered for normal use and a UE registered for emergency use.

[0008] The present disclosure provides a technique for separating a network between a terminal device registered for normal use and a terminal device registered for emergency use in an emergency.

[0009] In order to achieve the above object, a network node of an embodiment is a network node including a control unit and a communication unit, wherein the communication unit is configured to receive a message requesting that a terminal device use a first network slice in an emergency, the first network slice being a network slice allocated for emergency use, and the control unit is configured to determine whether the terminal device is registered for emergency use in an emergency, and if the terminal device is registered for emergency use, establish a PDU session with the terminal device through the first network slice, and if the terminal device is not registered for emergency use, reject the request.

[0010] Further, a method according to an embodiment is a method executed by a network node, comprising: receiving a message requesting that a terminal device use a first network slice in an emergency, the first network slice being a network slice allocated for emergency use; determining whether the terminal device is registered for emergency use; if the terminal device is registered for emergency use, establishing a PDU session with the terminal device through the first network slice; and if the terminal device is not registered for emergency use, rejecting the request.

[0011] According to the above configuration, in an emergency, only terminal devices registered for emergency use can use the emergency-dedicated network slice, thereby enabling the network to be separated between terminal devices registered for normal use and terminal devices registered for emergency use. Note that the above configuration may achieve other effects instead of or in addition to the above effect.

[0012] 1 is a diagram showing the configuration of a communication system according to the first embodiment. FIG. 2 is a block diagram showing the physical configuration of a network node according to the first embodiment. FIG. 3 is a block diagram showing the logical configuration of a network node according to the first embodiment. FIG. 4 is a block diagram showing the physical configuration of a terminal device according to the first embodiment. FIG. 5 is a block diagram showing the logical configuration of a terminal device according to the first embodiment. FIG. 6 is a diagram showing an overview of a network slice according to the first embodiment. FIG. 7 is a flowchart showing a network slice registration procedure according to the first embodiment. FIG. 8 is a flowchart showing a network slice registration procedure under normal circumstances according to the first embodiment. FIG. 9 is a flowchart showing a network slice registration procedure under an emergency according to the first embodiment. FIG. 10 is a flowchart showing a network slice registration procedure under an emergency according to the second embodiment. FIG. 11 is a flowchart showing a network slice registration procedure under an emergency according to the second embodiment. FIG. 12 is a flowchart showing a network slice selection procedure according to the second embodiment.

[0013] Hereinafter, the present embodiment will be described in detail with reference to the accompanying drawings. In this specification and drawings, elements that can be similarly described will be designated by the same reference numerals, and redundant description will be omitted.

[0014] Each embodiment described below is merely an example of a configuration that can realize this embodiment. Each embodiment described below can be modified or changed as appropriate depending on the configuration of the device to which this embodiment is applied and various conditions. Not all combinations of elements included in each embodiment described below are necessarily essential to realize this embodiment, and some elements can be omitted as appropriate. Therefore, the scope of this embodiment is not limited to the configurations described in each embodiment described below. As long as there are no mutual contradictions, a configuration that combines multiple configurations described in the embodiments described below can also be adopted.

[0015] 1. First Embodiment 1.1 Communication System The configuration of a communication system 1 according to an embodiment will be described with reference to FIG. 1 . As shown in FIG. 1 , the communication system 1 includes a network node 10, a terminal apparatus (Terminal Apparatus) 20, and a RAN node (Base Station Apparatus) 30. The network node 10 is connected to a data network (DN) 40. The DN 40 includes a network such as the Internet. The communication system 1 is configured in accordance with predetermined technical specifications (TS). For example, the communication system 1 may comply with technical specifications defined by 3GPP (e.g., 5G, 5G Advanced, 6G, etc.).

[0016] In the communication system 1, for example, communication is performed between each of the network nodes 10 described below in accordance with the 5G NR specification. Furthermore, communication is performed between the terminal device 20, the RAN node 30, and the network node 10. The section between the terminal device 20 and the RAN node 30 is a wireless section.

[0017] The network node 10 constitutes a core network. The network node 10 includes an Access and Mobility Management Function (AMF) 10a, a User Plane Function (UPF) 10b, a Unified Data Management (UDM) / Unified Data Repository (UDR) 10c, an Application Function (AF) 10d, a Network Slice Selection Function (NSSF) 10e, a Session Management Function (SMF) 10f, a Policy Control Function (PCF) 10g, and a Network Exposure Function (NEF).

[0018] The network nodes 10 are not limited to network nodes such as the AMF 10a described above, but may include other network nodes that are defined or will be defined in the 3GPP technical specifications. Furthermore, some of the network nodes 10, such as the AF 10d, do not necessarily constitute a core network. Such network nodes 10 are located outside the communication system 1 and communicate with network nodes 10 within the communication system 1 via the DN 40.

[0019] In the communication system 1, a user plane where user data is transmitted and received and a control plane where control data is transmitted and received are configured separately. That is, the communication system 1 supports C / U separation. The user plane is called the U-plane, and the control plane is called the C-plane.

[0020] The terminal device 20 may be a device that wirelessly communicates with the RAN node 30, and may be, for example, a user equipment (UE) that operates in accordance with the 3GPP 5G NR specifications, or may be any other device that is or will be defined in a 3GPP technical specification.

[0021] The terminal device 20 may be, for example, a mobile phone terminal such as a smartphone, a tablet terminal, a laptop PC, a communication module, a communication card, or an IoT device such as a surveillance camera or a robot. The terminal device 20 may be a vehicle (e.g., a car, a train, etc.) or a device provided therein. The terminal device 20 may be a transport vehicle other than a vehicle (e.g., a ship, an airplane, etc.) or a device provided therein. The terminal device 20 may be a sensor or a device provided therein. The terminal device 20 may also be referred to as a terminal, a mobile station, a mobile terminal, a mobile device, a mobile unit, a subscriber station, a subscriber terminal, a subscriber device, a subscriber unit, a wireless station, a wireless terminal, a wireless device, a wireless unit, a remote station, a remote terminal, a remote device, a remote unit, etc. The terminal device 20 may be a device adapted to one or more of enhanced Mobile Broadband (eMBB), Ultra-Reliable and Low Latency Communications (URLLC), and massive Machine Type Communications (mMTC).

[0022] The RAN node 30 forms a radio access network (RAN) and manages at least one cell. A cell constitutes the smallest unit of a communication area. For example, one cell belongs to one frequency (e.g., carrier frequency) and is composed of one component carrier. The term "cell" may represent wireless communication resources, or may represent a communication target of the terminal device 20. The RAN node 30 wirelessly communicates with the terminal device 20 located in its own cell in the U-plane and C-plane. In other words, the RAN node 30 terminates the U-plane protocol and the C-plane protocol for the terminal device 20.

[0023] The RAN node 30 communicates with the network node 10 in the U-plane and the C-plane. More specifically, the RAN node 30 connects to the AMF 10a via an NG-C interface (not shown) in the C-plane, and connects to the UPF 10b via an NG-U interface (not shown) in the U-plane.

[0024] The RAN node 30 may be, for example, a gNB that provides the terminal device 20 with a U-plane and a C-plane conforming to the 3GPP 5G NR specifications and connects to the 3GPP 5GC (5G Core Network). The RAN node 30 may also be any other device that is / will be defined in the 3GPP technical specifications.

[0025] Next, the physical configuration of the network node 10 will be described with reference to Fig. 2. As shown in Fig. 2, the network node 10 includes, as hardware elements, a processor 101, a memory 102, and a transceiver 103. The above-mentioned elements provided in the network node 10 are connected to each other by an internal bus. Note that the network node 10 may include hardware elements other than the elements shown in Fig. 2.

[0026] The processor 101 is a computing element that realizes various functions of the network node 10. The processor 101 may be a system-on-a-chip (SoC) that includes elements such as a central processing unit (CPU), a graphics processing unit (GPU), and a memory controller.

[0027] The memory 102 is configured by at least one storage medium such as a read-only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), or a solid state drive (SSD). The memory 102 is an element that temporarily or permanently stores programs and data used to execute various processes in the network node 10. The programs include one or more instructions for operating the network node 10. The processor 101 implements the functions of the network node 10 by expanding and executing the programs stored in the memory 102 in the memory 102 and / or a system memory (not shown).

[0028] The transceiver 103 transmits and receives signals to and from other network nodes 10 and RAN nodes 30 .

[0029] Next, the logical configuration of the network node 10 will be described with reference to Fig. 3. As shown in Fig. 3, the network node 10 includes, as functional blocks, a control unit 110 and a communication unit 120. The communication unit 120 includes at least one transmission unit 111 and at least one reception unit 122.

[0030] The control unit 110 may include at least one processor 101 and at least one memory 102. In other words, the control unit 110 may be realized by the processor 101 and the memory 102. The control unit 110 executes various control processes in the network node 10. For example, the control unit 110 controls communication with other nodes (e.g., other network nodes 10 and RAN node 30) via the communication unit 120. That is, the control unit 110 controls transmission and reception of data / information / messages via the communication unit 120.

[0031] The communication unit 120 includes the transceiver 103. In other words, the communication unit 120 is realized by the transceiver 103. The communication unit 120 communicates with other network nodes 10 and RAN nodes 30 by transmitting and receiving signals to and from the other network nodes 10 and RAN nodes 30.

[0032] The control unit 110 operates to execute various processes of the network node 10 of this embodiment.

[0033] Next, the physical configuration of the terminal device 20 will be described with reference to Fig. 4. As shown in Fig. 4, the terminal device 20 includes, as hardware elements, a processor 201, a memory 202, an input / output interface 203, a transceiver 204, and an antenna 205. The above elements provided in the terminal device 20 are connected to each other by an internal bus. Note that the terminal device 20 may include hardware elements other than the elements shown in Fig. 4.

[0034] The processor 201 is a computing element that realizes various functions of the terminal device 20. The processor 201 may be a CPU, and may further include other processors such as a GPU.

[0035] The memory 202 is composed of at least one storage medium such as a RAM. The memory 202 is an element that temporarily or permanently stores programs and data used to execute various processes in the terminal device 20. The programs include one or more instructions for operating the terminal device 20. The processor 201 implements the functions of the terminal device 20 by expanding and executing the programs stored in the memory 202 in the memory 202 and / or a system memory (not shown).

[0036] The input / output interface 203 is an interface that receives operations on the terminal device 20 and supplies the operations to the processor 201, and presents various information to the user. The input / output interface 203 is, for example, a touch panel.

[0037] The transceiver 204 is a circuit that performs various signal processing to realize wireless communication, and includes a baseband processor and an RF circuit. The transceiver 204 transmits and receives wireless signals to and from the RAN node 30 via the antenna 205.

[0038] Next, the logical configuration of the terminal device 20 will be described with reference to Fig. 5. As shown in Fig. 5, the terminal device 20 includes, as functional blocks, a control unit 210 and a communication unit 220. The communication unit 220 includes at least one transmission unit 121 and at least one reception unit 122.

[0039] The control unit 210 may include at least one processor 201 and at least one memory 202. In other words, the control unit 210 may be realized by the processor 201 and the memory 202. The control unit 210 executes various control processes in the terminal device 20. For example, the control unit 210 controls wireless communication with the RAN node 30 via the communication unit 220. That is, the control unit 210 controls transmission and reception of data / information / messages via the communication unit 220.

[0040] The communication unit 220 includes the transceiver 204 and the antenna 205. In other words, the communication unit 220 is realized by the transceiver and the antenna 205. The communication unit 220 wirelessly communicates with the RAN node 30 by transmitting and receiving radio signals to and from the RAN node 30.

[0041] The control unit 210 operates to execute various processes of the terminal device 20 of this embodiment.

[0042] 1.2 Network Slices Next, an overview of network slices will be described with reference to Fig. 6. Each network slice is established by virtually dividing the network so that a terminal device 20 can communicate with a DN 40 via a RAN node 30 and a network node (UPF) 10. In a network slice, data is conveyed by establishing a protocol data unit (PDU) session between the terminal device 20 and the network node 10.

[0043] As shown in Figure 6, multiple network slices are established between the terminal device 20 and the network node 10. Each network slice is identified by an S-NSSAI.

[0044] The data format of the S-NSSAI includes a slice / service type (SST) and a slice differentiator (SD).

[0045] The SST defines the use of network slices and includes standard SSTs and individual SSTs. The standard SST defines eMBB, URLLC, Massive Internet of Things (MIoT), Vehicle to X (V2X), and High Performance Machine Type Communication (HMTC). The individual SST defines uses that can be freely set by operators. The SD is an identifier for separating multiple network slices in the same SST.

[0046] 1.3 Network Slice Registration The terminal device 20 holds an S-NSSAI applicable within a Public Land Mobile Network (PLMN). This S-NSSAI is called a Configured S-NSSAI. The terminal device 20 registers the S-NSSAI by executing a registration request to the AMF 10a. An example of an S-NSSAI registration procedure will be described with reference to FIG. 7.

[0047] First, the terminal device 20 transmits a registration request message to the RAN node 30 (step S701). The registration request message includes an S-NSSAI. This S-NSSAI is called a Requested S-NSSAI.

[0048] Next, the RAN node 30 selects an AMF 10a based on the Requested S-NSSAI and transmits a registration request message to the selected AMF 10a (step S702).

[0049] Next, the AMF 10a selects the UDM / UDR 10c and registers the S-NSSAI in the selected UDM / UDR 10c (step S703). This S-NSSAI is called a subscribed S-NSSAI. The subscribed S-NSSAI is stored in the UDM / UDR 10c as subscription data.

[0050] Next, the AMF 10a notifies the terminal device 20 of the registered S-NSSAI (step S703). This S-NSSAI is called an Allowed S-NSSAI.

[0051] In this way, the terminal device 20 can establish a PDU session corresponding to the network slice with the UPF 10b and communicate with the DN 40 through the established PDU session.

[0052] 1.4 Emergency-dedicated network slice Non-Patent Document 1 describes an emergency service that prioritizes IMS service sessions for UEs registered for emergency use over UEs registered for normal use when an emergency occurs. In the emergency service described in Non-Patent Document 1, UEs registered for emergency use can use services such as calls preferentially, but they cannot use the network exclusively. In the event of an unprecedented large-scale disaster, it is expected that a huge amount of traffic will be generated in the network covering the area affected by the disaster.

[0053] In the above-described case, even if a session is prioritized for a UE registered for emergency use, traffic caused by UEs registered for normal use occurs in the network, so that the UE registered for emergency use may still be unable to make sufficient calls, etc. On the other hand, because a session is prioritized for a UE registered for emergency use, a UE registered for normal use may be unable to make calls at all.

[0054] In light of the above, it is preferable to separate the network between terminal devices registered for normal use and terminal devices registered for emergency use when an emergency occurs.

[0055] In the first embodiment, in an emergency, a network slice that is permitted to be used only by a terminal device 20 registered for emergency use, i.e., a network slice allocated for emergency use, is established. Hereinafter, such a network slice is referred to as an emergency dedicated network slice or a first network slice. The emergency dedicated network slice is not used during normal times, i.e., when no emergency occurs. Furthermore, a network slice not allocated for emergency use is referred to as a normal network slice or a second network slice.

[0056] The emergency-only network slice may be identified, for example, by a standard SST or an individual SST among the SSTs in the S-NSSAI. For example, the emergency-only network slice may be assigned a value of "X: Emergency" to the standard SST or the individual SST. In this way, the emergency-only network slice can be identified.

[0057] In addition, an emergency-only network slice may be identified as an emergency-only network slice not only by the value of the SST but also by other data fields.

[0058] Next, an example of an S-NSSAI registration procedure under normal circumstances will be described with reference to Figure 8. As described above, an emergency-dedicated network slice is not used under normal circumstances. In the procedure shown in Figure 8, registration of an emergency-dedicated network slice is rejected under normal circumstances. In this way, by not allowing the emergency-dedicated network slice to be used under normal circumstances, when an emergency occurs, a terminal device 20 registered for emergency use can immediately and exclusively use the emergency-dedicated network slice.

[0059] First, the terminal device 20 transmits a registration request message to the RAN node 30 (step S801). The registration request message includes an S-NSSAI. This S-NSSAI is referred to as a Requested S-NSSAI. The S-NSSAI included in the registration request message includes a value indicating that the network slice is an emergency-dedicated network slice, for example, in an SST. Alternatively, the registration request message may include, in addition to the S-NSSAI, an indicator indicating that the network slice for which registration is requested is an emergency-dedicated network slice.

[0060] Next, the RAN node 30 selects the AMF 10a based on the Requested S-NSSAI and transmits a registration request message to the selected AMF 10a (step S802).

[0061] The AMF 10a determines whether the Requested S-NSSAI is an emergency-dedicated network slice based on the value of the SST included in the registration request message (step S803). If the Requested S-NSSAI is an emergency-dedicated network slice, the process proceeds to step S804. If the Requested S-NSSAI is an emergency-dedicated network slice, the process proceeds to step S804. If the Requested S-NSSAI is not an emergency-dedicated network slice, the process proceeds to step S806.

[0062] In step S804, the AMF 10a rejects the registration of the S-NSSAI, and then transmits a registration rejection message to the terminal device 20 (step S805).

[0063] In step S806, the AMF 10a selects the UDM / UDR 10c and registers the S-NSSAI in the selected UDM / UDR 10c as a Subscribed S-NSSAI. The Subscribed S-NSSAI is stored in the UDM / UDR 10c as subscription data. Then, the AMF 10a notifies the terminal device 20 of the Allowed S-NSSAI (step S807).

[0064] In this way, the use of the emergency-dedicated network slice is denied under normal circumstances, so that in the event of an emergency, the terminal device 20 registered for emergency use can immediately and exclusively use the emergency-dedicated network slice.

[0065] In the present embodiment, an example has been described in which the processes in steps S803 to S807 are executed by the AMF 10a, but the present invention is not limited to such an example. The processes in steps S803 to S807 may be executed by another network node 10, such as the PCF 10g, alone or in cooperation with the other network node 10.

[0066] Next, an example of an S-NSSAI registration procedure in an emergency will be described with reference to Figure 9. In this embodiment, emergency vehicles and emergency communication terminals are grouped for each area, such as each prefecture or city, town, or village, and a group of emergency terminal devices 20 is registered as emergency terminal devices. Hereinafter, terminal devices 20 registered for emergency use will be referred to as emergency terminal devices 20. Furthermore, terminal devices 20 not registered for emergency use will be referred to as normal terminal devices 20 or non-emergency terminal devices 20.

[0067] The emergency terminal devices 20 are managed as a group by the AF 10d. The emergency terminal devices 20 may be identified by an identifier (UE-ID) of the terminal device 20 such as an International Mobile Subscriber Identity (IMSI). The emergency terminal devices 20 may also be registered in subscription data. In this case, the subscription data includes data indicating that the terminal devices 20 are emergency terminal devices.

[0068] When an emergency occurs, AF10d requests a group of emergency terminal devices 20 to use an emergency-dedicated network slice. In this way, a group of emergency terminal devices 20 can exclusively use an emergency-dedicated network slice for each area, such as each prefecture or city / town / village.

[0069] First, the AF 10d sends a message to each of a group of emergency terminal devices 20 that it manages, requesting the use of an emergency-dedicated network slice (step S901). In response to this request message, each of the emergency terminal devices 20 sends a response message to the AF 10d (step S902).

[0070] It is to be noted that, at the time of step S901, each of the group of emergency terminal devices 20 may be using a normal network slice. In this case, AF 10d sends a message to each of the group of emergency terminal devices 20 requesting switching from a normal network slice to an emergency-only network slice. Then, in response to the message in step S902, AF 10d uses an API service via NEF 10h to send a message to SMF 10g requesting disconnection of the PDU session established for the emergency terminal device 20 through the normal network slice. In response to this request message, SMF 10f disconnects the PDU session established for the emergency terminal device 20.

[0071] Next, the AF 10d uses an API service via the NEF 10h to send a message to the PCF 10g requesting that the group of emergency terminal devices 20 use an emergency-dedicated network slice (step S903).

[0072] Next, the PCF 10g confirms that each of the group of emergency terminal devices 20 is a terminal device registered for emergency use based on the identifier (UE-ID) of the terminal device 20, such as the IMSI registered in the HRL (step S904). Alternatively, the PCF 10g may confirm that each of the group of emergency terminal devices 20 is a terminal device registered for emergency use based on subscription data registered in the UDM / UDR.

[0073] In the process of step S904, if the emergency terminal device 20 is not a terminal device registered for emergency use, the PCF 10g may transmit a registration rejection message to the AF 10d (not shown).

[0074] Next, the PCF 10g uses the API service via the NEF 10h to send a response message to the AF 10d (step S905).

[0075] Next, the AF 10d uses the API service via the NEF 10h to send a message to the NSSF 10e requesting that an emergency-dedicated network slice be selected. In response to this request message, the NSSF 10e selects the emergency-dedicated network slice (step S906).

[0076] The emergency-dedicated network slice may be allocated in advance for each AF 10d, that is, for each area such as each prefecture or city, town, or village. In this case, in step S906, the request message sent by the AF 10d to the NSSF 10e includes an S-NSSAI. The S-NSSAI included in the registration request message includes a value indicating that the network slice is an emergency-dedicated network slice in the SST, etc. Alternatively, the registration request message may include, in addition to the S-NSSAI, an indicator indicating that the network slice for which registration is requested is an emergency-dedicated network slice.

[0077] Alternatively, in the processing of step S906, the NSSF 10e may select a network slice assigned as an emergency-only network slice from among the S-NSSAIs registered in the UDM / UDR 10c.

[0078] Next, the NSSF 10e sends a message to the SMF 10f requesting the establishment of a PDU session through the selected emergency-dedicated network slice. In response to this request message, the SMF 10f establishes a PDU session for the emergency-dedicated network slice selected in step S906 (step S907). The SMF 10f sends a message indicating that the PDU session has been established to each of the group of emergency terminal devices 20. In this way, a PDU session through the emergency-dedicated network slice is established for the group of emergency terminal devices 20.

[0079] In this way, in the event of an emergency, a group of emergency terminal devices 20 can exclusively use the emergency-only network slice, thereby separating the network between normal terminal devices 20 and emergency terminal devices 20.

[0080] In the example shown in FIG. 9, AF 10d requests a group of emergency terminal devices 20 to use (switch to) a network slice. It is assumed that, when an emergency occurs, the users of the emergency terminal devices 20 do not necessarily understand that they need to use an emergency-dedicated network slice. In this embodiment, AF 10d manages the emergency terminal devices 20 as a group and requests that the network slice be switched for the entire group. In this way, even when the above-mentioned situation is assumed, each of the group of emergency terminal devices 20 can use an emergency-dedicated network slice in an emergency.

[0081] 9, as described above, the PDU session established through the normal network slice is disconnected at step S901. Alternatively, if a User Equipment Route Selection Policy (URSP) is supported for the emergency terminal device 20, a PDU session may be established through the emergency-dedicated network slice without disconnecting the PDU session established through the normal network slice.

[0082] If URSP is supported for the emergency terminal device 20, the emergency terminal device 20 can select and use any one of multiple network slices specified in the URSP rule. The URSP rule specifies a network slice and a corresponding PDU session. In this case, the PCF 10g may add an emergency-dedicated network slice to the URSP rule. The URSP rule is transmitted to the emergency terminal device 20 via the AMF 10a, so that the emergency terminal device 20 can select the added emergency-dedicated network slice based on the URSP rule. In this way, the emergency terminal device 20 can use the emergency-dedicated network slice without disconnecting the PDU session established through the normal network slice. Such an alternative example also applies to the procedures described with reference to Figures 10, 11, and 12 below.

[0083] In addition, in the procedure shown in Fig. 9, the PCF 10g, NSSF 10e, and SMF 10f cooperate to establish a PDU session in response to a request from the AFd, but the present invention is not limited to such an example. A PDU session may also be established in response to a request from the terminal device 20. With reference to Fig. 10, an example of an S-NSSAI registration procedure in an emergency will be described as a modified example of the procedure shown in Fig. 9. In the procedure shown in Fig. 10, a PDU session is established in response to a request from the terminal device 20.

[0084] First, the AF 10d sends a message to each of a group of emergency terminal devices 20 that it manages, requesting the use of an emergency-dedicated network slice (step S1001). In response to this request message, each of the emergency terminal devices 20 sends a response message to the AF 10d (step S1002).

[0085] It is to be noted that, at the time of step S1001, each of the group of emergency terminal devices 20 may be using a normal network slice. In this case, AF 10d sends a message to each of the group of emergency terminal devices 20 requesting switching from the normal network slice to the emergency-dedicated network slice. Then, in response to the message in step S1002, AF 10d uses an API service via NEF 10h to send a message to SMF 10g requesting disconnection of the PDU session established for the emergency terminal device 20 through the normal network slice. In response to this request message, SMF 10f disconnects the PDU session established for the emergency terminal device 20.

[0086] Next, each of the emergency terminal devices 20 transmits a message to the PCF 10g via the RAN node 30 (not shown) requesting the use of the emergency-dedicated network slice (step S1003). Note that in the processing of step S1003, the AF 10d may transmit a request message to the PCF 10g, similar to the processing of step S903 shown in FIG. 9.

[0087] Next, the PCF 10g confirms that each of the group of emergency terminal devices 20 is a terminal device registered for emergency use based on the identifier (UE-ID) of the terminal device 20, such as the IMSI registered in the HRL (step S1004). Alternatively, the PCF 10g may confirm that each of the group of emergency terminal devices 20 is a terminal device registered for emergency use based on the subscription data registered in the UDM / UDR.

[0088] In the process of step S1004, if the emergency terminal device 20 is not a terminal device registered for emergency use, the PCF 10g may transmit a registration rejection message to each of the group of emergency terminal devices 20 (not shown).

[0089] Next, the PCF 10g transmits a response message to each of the emergency terminal devices 20 via the RAN node 30 (not shown) (step S1005).

[0090] Next, each of the group of emergency terminal devices 20 transmits a request message to the NSSF 10e requesting the selection of an emergency-dedicated network slice. In response to this request message, the NSSF 10e selects the emergency-dedicated network slice (step S1006). Note that in the processing of step S1006, the AF 10d may transmit the request message to the NSSF 10e, similar to the processing of step S906 shown in FIG. 9 .

[0091] When an emergency-dedicated network slice is pre-allocated for each AF 10d, in step S1006, the request message transmitted by each of the group of emergency terminal devices 20 to the NSSF 10e includes an S-NSSAI. The S-NSSAI included in the registration request message includes a value indicating that the network slice is an emergency-dedicated network slice in the SST, etc. Alternatively, the registration request message may include, in addition to the S-NSSAI, an indicator indicating that the network slice for which registration is requested is an emergency-dedicated network slice.

[0092] Alternatively, in the processing of step S1006, the NSSF 10e may select a network slice assigned as an emergency-only network slice from among the S-NSSAIs registered in the UDM / UDR 10c.

[0093] Next, the NSSF 10e sends a request message to the SMF 10f requesting the establishment of a PDU session through the selected emergency-dedicated network slice. In response to this request message, the SMF 10f establishes a PDU session for the emergency-dedicated network slice selected in step S1006 (step S1007). The SMF 10f sends a message indicating that the PDU session has been established to each of the group of emergency terminal devices 20. In this way, a PDU session through the emergency-dedicated network slice is established for the group of emergency terminal devices 20.

[0094] The procedure shown in Figure 10 also allows a group of emergency terminal devices 20 to exclusively use an emergency-only network slice when an emergency occurs, thereby separating the network between normal terminal devices 20 and emergency terminal devices 20.

[0095] 9 and 10, the S-NSSAI registration procedure is executed in response to a trigger from the AF 10d that manages the group of emergency terminal devices 20, but the S-NSSAI registration procedure may also be executed in response to a trigger from the terminal device 20 without going through the processing by the AF 10d. In this case, of the processing shown in FIG. 10, only the processing from step S1003 to step S1007 is executed.

[0096] The first embodiment has been described above. In the first embodiment, the network is separated between the normal terminal device 20 and the emergency terminal device 20. Furthermore, the emergency-dedicated network slice is not used during normal times, and the emergency-dedicated network slice is used by the emergency terminal device 20 only during emergencies. Therefore, when an emergency occurs, the emergency terminal device 20 can immediately and exclusively use the emergency-dedicated network slice.

[0097] 9 and 10 are executed by the PCF 10g, the NSSF 10e, and the SMF 10g, but this is merely an example. Some of the processes in the procedures described in the first embodiment are executed by one or more of the network nodes 10.

[0098] 2. Second Embodiment Next, a second embodiment will be described. In the second embodiment, the emergency-only network slice described in the first embodiment is also used during normal times. During normal times, the emergency-only network slice is permitted to be used not only by emergency terminal devices 20 but also by normal terminal devices 20. When an emergency occurs, the emergency-only network slice is permitted to be used only by emergency terminal devices 20.

[0099] During normal times, a PDF session is established through the emergency-only network slice upon request from the emergency terminal device 20 and the normal terminal device 20 according to the procedure shown in Figure 7. In this way, by allowing the use of the emergency-only network slice even during normal times, resources can be used efficiently.

[0100] An example of the S-NSSAI registration procedure in an emergency will be described with reference to Fig. 11. In this embodiment, emergency vehicles and emergency communication terminals are grouped for each area such as each prefecture or city, town, or village, and groups of emergency terminal devices 20 are registered.

[0101] In the procedure shown in Figure 11, it is assumed that the emergency-only network slice is normally used by the terminal device 20 until an emergency occurs.

[0102] First, the AF 10d sends a message to each of a group of emergency terminal devices 20 that it manages, requesting the use of an emergency-dedicated network slice (step S1101). In response to this request message, each of the emergency terminal devices 20 sends a response message to the AF 10d (step S1102).

[0103] At the time of step S1101, if each of the group of emergency terminal devices 20 is using a normal network slice, AF 10d sends a message requesting switching to an emergency-dedicated network slice. Then, in response to the message in step S1102, AF 10d uses an API service via NEF 10h to send a message to SMF 10g requesting disconnection of the PDU session established for the emergency terminal device 20 through the normal network slice. In response to this request message, SMF 10f disconnects the PDU session established for the emergency terminal device 20.

[0104] Next, the AF 10d uses an API service via the NEF 10h to send a message to the PCF 10g requesting that the group of emergency terminal devices 20 use an emergency-dedicated network slice (step S1103).

[0105] Next, the PCF 10g confirms that each of the group of emergency terminal devices 20 is a terminal device registered for emergency use based on the identifier (UE-ID) of the terminal device 20, such as the IMSI registered in the HRL (step S1104). Alternatively, the PCF 10g may confirm that each of the group of emergency terminal devices 20 is a terminal device registered for emergency use based on the subscription data registered in the UDM / UDR.

[0106] In the process of step S1104, if the emergency terminal device 20 is not a terminal device registered for emergency use, the PCF 10g may transmit a registration rejection message to the AF 10d (not shown).

[0107] Next, the PCF 10g uses the API service via the NEF 10h to send a response message to the AF 10d (step S1105).

[0108] Next, the AF 10d uses the API service via the NEF 10h to send a request message to the NSSF 10e requesting selection of an emergency-dedicated network slice. In response to the request message, the NSSF 10e selects the emergency network slice (step S1106).

[0109] When an emergency-dedicated network slice is pre-allocated for each AF 10d, in step S1106, the request message transmitted by each of the group of emergency terminal devices 20 to the NSSF 10e includes an S-NSSAI. The S-NSSAI included in the registration request message includes a value indicating that the network slice is an emergency-dedicated network slice in the SST, etc. Alternatively, the registration request message may include, in addition to the S-NSSAI, an indicator indicating that the network slice for which registration is requested is an emergency-dedicated network slice.

[0110] Alternatively, in the processing of step S1106, the NSSF 10e may select a network slice assigned as an emergency-dedicated network slice from among the S-NSSAIs registered in the UDM / UDR 10c. As described above, the emergency-dedicated network slice selected by either method is assumed to be normally used by the terminal device 20.

[0111] Next, the NSSF 10e sends a message to the SMF 10f, requesting that the SMF 10f disconnect the PDU session established with the normal terminal device 20 through the selected emergency-dedicated network slice. In response to this request message, the SMF 10f disconnects the PDU session established with the normal terminal device 20 (step S1107). In the processing of step S1107, the network node 10, such as the AF 10d, may send a message to the terminal device 20, before disconnecting the PDU session, notifying the terminal device 20 that a disaster has occurred and that another network slice will be switched.

[0112] Whether or not a PDU session is established for a normal terminal device 20 may be determined by a network node 10 such as AMF 10a, PCF 10e, or SMF 10f based on an identifier (UE-ID) of the terminal device 20, such as an IMSI registered in the HRL, or subscription data registered in the UDM / UDR.

[0113] Next, the NSSF 10e transmits a request message requesting the establishment of a PDU session through the selected emergency-dedicated network slice. In response to this request message, the SMF 10f establishes a PDU session for the emergency-dedicated network slice selected in step S1106 (step S1108). The SMF 10f transmits a message indicating that a PDU session has been established to each of the group of emergency terminal devices 20. In this way, a PDU session through the emergency-dedicated network slice is established for the group of emergency terminal devices 20, while the PDU session established for the normal terminal devices 20 is disconnected.

[0114] In this way, resources can be used efficiently by allowing the use of an emergency-only network slice during normal times, while allowing only the emergency terminal device 20 to use the emergency-only network slice during an emergency.

[0115] In the procedure shown in Fig. 11, the PCF 10g, NSSF 10e, and SMF 10f cooperate to disconnect and establish a PDU session in response to a request from the AFd, but the procedure is not limited to such an example. The PDU session may also be disconnected and established in response to a request from the terminal device 20. With reference to Fig. 12, an example of an S-NSSAI registration procedure in an emergency will be described as a modified example of the procedure shown in Fig. 11. In the procedure shown in Fig. 12, the PDU session is disconnected and established in response to a request from the terminal device 20.

[0116] First, the AF 10d sends a message to each of a group of emergency terminal devices 20 that it manages, requesting the use of an emergency-dedicated network slice (step S1201). In response to this request message, each of the emergency terminal devices 20 sends a response message to the AF 10d (step S1202).

[0117] Note that, at the time of step S1201, if each of the group of emergency terminal devices 20 is using a normal network slice, AF 10d sends a message requesting switching to an emergency-dedicated network slice. Then, in response to the message in step S1202, AF 10d uses an API service via NEF 10h to send a message to SMF 10g requesting disconnection of the PDU session established for the emergency terminal device 20 through the normal network slice. In response to this request message, SMF 10f disconnects the PDU session established for the emergency terminal device 20.

[0118] Next, each of the emergency terminal devices 20 transmits a message to the PCF 10g via the RAN node 30 (not shown) requesting the use of the emergency-dedicated network slice (step S1203). Note that in the processing of step S1203, the AF 10d may transmit a request message to the PCF 10g, similar to the processing of step S1103 shown in FIG. 11.

[0119] Next, the PCF 10g confirms that each of the group of emergency terminal devices 20 is a terminal device registered for emergency use, based on the identifier (UE-ID) of the terminal device 20, such as the IMSI registered in the HRL (step S1204). Alternatively, the PCF 10g may confirm that each of the group of emergency terminal devices 20 is a terminal device registered for emergency use, based on subscription data registered in the UDM / UDR.

[0120] In the process of step S1204, if the emergency terminal device 20 is not a terminal device registered for emergency use, the PCF 10g may transmit a registration rejection message to each of the group of emergency terminal devices 20 (not shown).

[0121] Next, the PCF 10g transmits a response message to each of the emergency terminal devices 20 via the RAN node 30 (not shown) (step S1205).

[0122] Next, each of the group of emergency terminal devices 20 transmits a request message to the NSSF 10e requesting the selection of an emergency-dedicated network slice. In response to this request message, the NSSF 10e selects the emergency-dedicated network slice (step S1206). Note that in the processing of step S1206, the AF 10d may transmit the request message to the NSSF 10e, similar to the processing of step S1106 shown in FIG. 9 .

[0123] When an emergency-dedicated network slice is pre-allocated for each AF 10d, in step S1206, the request message transmitted by each of the group of emergency terminal devices 20 to the NSSF 10e includes an S-NSSAI. The S-NSSAI included in the registration request message includes a value indicating that the network slice is an emergency-dedicated network slice in the SST, etc. Alternatively, the registration request message may include, in addition to the S-NSSAI, an indicator indicating that the network slice for which registration is requested is an emergency-dedicated network slice.

[0124] Alternatively, in the processing of step S1006, the NSSF 10e may select a network slice assigned as an emergency-dedicated network slice from among the S-NSSAIs registered in the UDM / UDR 10c. As described above, the emergency-dedicated network slice selected by either method is assumed to be normally used by the terminal device 20.

[0125] Next, the NSSF 10e sends a message to the SMF 10f requesting that the SMF 10f disconnect the PDU session established with the normal terminal device 20 through the selected emergency-dedicated network slice. In response to this request message, the SMF 10f disconnects the PDU session established with the normal terminal device 20 (step S1207). In the processing of step S1207, the network node 10 such as the AF 10d may send a message to the terminal device 20 notifying that a disaster has occurred and that another network slice will be switched, before disconnecting the PDU session.

[0126] Whether or not a PDU session is established for a normal terminal device 20 may be determined by a network node 10 such as AMF 10a, PCF 10e, or SMF 10f based on an identifier (UE-ID) of the terminal device 20, such as an IMSI registered in the HRL, or subscription data registered in the UDM / UDR.

[0127] Next, the NSSF 10e sends a request message to the SMF 10f requesting the establishment of a PDU session through the selected emergency-dedicated network slice. In response to this request message, the SMF 10f establishes a PDU session for the emergency-dedicated network slice selected in step S1206 (step S1208). The SMF 10f sends a message indicating that the PDU session has been established to each of the group of emergency terminal devices 20. In this way, a PDU session through the emergency-dedicated network slice is established for the group of emergency terminal devices 20.

[0128] The procedure shown in Figure 12 also enables efficient use of resources by allowing the use of an emergency-only network slice during normal times, while allowing only the emergency terminal device 20 to use the emergency-only network slice during an emergency.

[0129] The second embodiment has been described above. In the second embodiment, the network is also separated between the normal terminal device 20 and the emergency terminal device 20. Furthermore, an emergency-dedicated network slice is used during normal times, while the emergency-dedicated network slice is used only by the emergency terminal device 20 during an emergency. This allows for efficient use of resources.

[0130] In the first embodiment, the PCF 10g, the NSSF 10e, and the SMF 10g execute the processes in the procedures shown in Fig. 11 and Fig. 12, but this is merely an example. Some of the processes in the procedures described in the first embodiment are executed by one or more of the network nodes 10.

[0131] 3. Third Embodiment Next, a third embodiment will be described. In the third embodiment, an emergency-dedicated network slice is selected based on service requirements for a network in an area where a disaster occurs.

[0132] For example, the traffic of the network slice used in an emergency varies depending on the number of terminal devices 20 present in a specific area where a disaster occurs. In some cases, congestion may occur in the selected emergency-dedicated network slice due to the traffic caused by the number of UEs.

[0133] When a disaster such as an earthquake, tsunami, volcanic eruption, or flood occurs, the location of the disaster is notified to the network. In the third embodiment, the area where the disaster occurred is identified based on such notification, and service requirements for the network are determined based on the number of terminal devices 20 in that area, etc. Then, an emergency-dedicated network slice corresponding to the service requirements is selected.

[0134] A procedure for selecting an emergency-dedicated network slice according to this embodiment will be described with reference to Fig. 13. The procedure shown in Fig. 13 is applicable to any of the procedures shown in Fig. 9, Fig. 10, Fig. 11, and Fig. 12.

[0135] When the procedure shown in Fig. 13 is applied to the procedure shown in Fig. 9, the procedure shown in Fig. 13 shows details of step S906 in the procedure shown in Fig. 9. Similarly, when the procedure shown in Fig. 13 is applied to the procedure shown in Fig. 10, the procedure shown in Fig. 13 shows details of step S1006 in the procedure shown in Fig. 10. Similarly, when the procedure shown in Fig. 13 is applied to the procedure shown in Fig. 11, the procedure shown in Fig. 13 shows details of step S1106 in the procedure shown in Fig. 11. Similarly, when the procedure shown in Fig. 13 is applied to the procedure shown in Fig. 12, the procedure shown in Fig. 13 shows details of step S1206 in the procedure shown in Fig. 12.

[0136] First, the NSSF 10e transmits a message to the AMF 10a requesting that the AMF 10a calculate the number of terminal devices 20 present in the area where the disaster has occurred. In response to this request message, the AMF 10a calculates the number of terminal devices 20 present in the area (step S1301).

[0137] The area where the disaster occurred is notified by an external server (not shown) that notifies emergency earthquake alerts, disaster occurrence locations, etc. The AMF 10a calculates the number of terminal devices 20 present in the area based on the number of terminal devices 20 registered in the UDM / UDR 10c.

[0138] Next, the NSSF 10e determines service requirements of the network slice to be used in the area where the disaster occurred based on the number of terminal devices 20 (step S1302). The service requirements may be determined, for example, with respect to the QoS parameters shown in Table 1. The technical specifications defined by 3GPP define the QoS parameters shown in Table 1.

[0139] The NSSF 10e determines the service requirements based on the number of terminal devices 20 for the QoS parameters shown in Table 1. The service requirements may be stored as a service requirement list in association with the number of terminal devices 20 for the QoS parameters shown in Table 1. Table 2 shows an example of the service requirement list.

[0140] Next, the NSSF 10e selects an emergency-dedicated network slice that satisfies the service requirements determined in step S1302 (step S1303). This selection is performed by selecting an S-NSSAI from the S-NSSAIs registered in the UDM / UDR 10c.

[0141] To select an emergency-dedicated network slice that satisfies the service requirements, QoS values ​​corresponding to the QoS provided by each network slice may be stored in the UDM / UDR 10c. The QoS values ​​may be stored as a QoS list in association with the S-NSSAI for each network slice for the QoS parameters shown in Table 1. Table 3 shows an example of the QoS list.

[0142] By storing the QoS list in the UDM / UDR 10c, an emergency dedicated network slice that meets the service requirements can be appropriately selected. Also, by storing the QoS list in the UDM / UDR 10c, the above selection can be performed at a detailed QoS level.

[0143] In this way, by selecting an emergency-dedicated network slice based on the service requirements for the network in the area where the disaster occurs, the emergency terminal device 20 can use an appropriate network slice in an emergency.

[0144] In this embodiment, the network node 10 such as the AMF 10a determines the service requirements based on the number of registered UEs, but the present invention is not limited to such an example. For example, the AF 10d may determine the service requirements based on the number of terminal devices 20 that it manages.

[0145] The third embodiment has been described above. In the third embodiment, an emergency-dedicated network slice is selected based on service requirements for a network in an area where a disaster occurs. In this way, when an emergency occurs, the emergency terminal device 20 can use an appropriate network slice that satisfies the service requirements.

[0146] In the third embodiment, the execution entities of each process in the procedure shown in Fig. 13 are the AMF 10a and the NSSF 10e, but this is merely an example. Some of the processes in the procedure described in the first embodiment are executed by one or more of the network nodes 10.

[0147] While the embodiments for carrying out the present invention have been described above, the present invention is not limited to the above-described embodiments. It is to be understood that the above-described embodiments are merely examples and that various modifications are possible.

[0148] The words, phrases, and other expressions used in the above embodiments are merely examples and may be replaced with substantially identical or similar expressions. In particular, since the technology according to the above embodiments relates to technical specifications, the expressions in the above embodiments may be replaced with substantially identical or similar expressions in technical specifications (e.g., technical specifications cited in this specification).

[0149] The information transmitted and received in the above embodiment may be contained in the same or a different message or element already described in the technical specifications, or may be contained in a newly defined message or element. The information transmitted and received in the above embodiment may be transmitted and received using a different layer and / or a different channel than those in the above embodiment.

[0150] The means and / or functions provided by the devices described in the above embodiments can be provided by software recorded in a tangible memory device and a computer that executes the software, software alone, hardware alone, or a combination thereof. For example, if any of the above devices is provided by an electronic circuit that is hardware, it can be provided by a digital circuit including a large number of logic circuits, or an analog circuit.

[0151] The device described in the above embodiment executes a program stored in a non-transitory tangible storage medium, and the execution of the program executes a method corresponding to the program.

[0152] 5. Supplementary Notes Some or all of the above embodiments and modified examples may also be described as in the following supplementary notes, but are not limited to the contents of the supplementary notes. Below, a relationship is expressed in which a supplementary note that is dependent on multiple supplementary notes is dependent on another supplementary note that is dependent on multiple supplementary notes. All of the dependency relationships of the supplementary notes expressed below are included in the above embodiments.

[0153] (Supplementary Note 1) A network node including a control unit and a communication unit, wherein the communication unit is configured to receive a message requesting that a terminal device use a first network slice in an emergency, the first network slice being a network slice allocated for emergency use, and the control unit is configured to: in an emergency, determine whether the terminal device is registered for emergency use, establish a PDU session with the terminal device through the first network slice if the terminal device is registered for emergency use, and reject the request if the terminal device is not registered for emergency use.

[0154] (Supplementary Note 2) The network node according to Supplementary Note 1, wherein the communication unit is further configured to receive a message requesting that the terminal device use the first network slice under normal circumstances, and the control unit is further configured to reject the request under normal circumstances.

[0155] (Supplementary Note 3) The network node described in Supplementary Note 1, wherein the communication unit is further configured to receive a message requesting that the terminal device use the first network slice under normal circumstances, and the control unit is further configured to register the first network slice under normal circumstances.

[0156] (Supplementary Note 4) The network node according to Supplementary Note 3, wherein the control unit is further configured to disconnect the PDU session established during normal times.

[0157] (Supplementary Note 5) A network node described in any one of Supplementary Notes 1 to 4, configured such that, when the terminal device normally uses a second network slice that is not allocated for emergency use, the communication unit is further configured to receive a message requesting that the terminal device switch from the second network slice to the first network slice in an emergency, and the control unit is further configured to disconnect a PDU session established with the terminal device through the second network slice in an emergency.

[0158] (Supplementary Note 6) The network node according to any one of Supplementary Notes 1 to 5, wherein a group including a plurality of terminal devices is registered with the first network slice, and the communication unit is further configured to receive a message requesting that each of the group use the first network slice in an emergency.

[0159] (Supplementary Note 7) The network node according to Supplementary Note 6, wherein the communication unit is further configured to send a message to each of the group requesting use of the first network slice.

[0160] (Supplementary Note 8) The network node according to any one of Supplementary Notes 1 to 7, wherein the control unit is further configured to determine, based on an identifier of the terminal device, whether the terminal device is registered for emergency use.

[0161] (Supplementary Note 9) The network node according to any one of Supplementary Notes 1 to 7, wherein the control unit is further configured to determine whether the terminal device is registered for emergency use based on subscription data.

[0162] (Supplementary Note 10) The network node according to any one of Supplementary Notes 1 to 9, wherein the control unit is further configured to: determine service requirements of a network in an area where a disaster occurs in an emergency; and select the first network slice from among network slices allocated for emergency use based on the service requirements.

[0163] (Supplementary Note 11) The network node according to Supplementary Note 10, wherein the control unit is further configured to: calculate the number of terminal devices registered for emergency use that are present within the area; and determine the service requirements based on the number of terminal devices.

[0164] (Supplementary Note 12) A method executed by a network node, comprising: in an emergency, receiving a message requesting that a terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; determining whether the terminal device is registered for emergency use; if the terminal device is registered for emergency use, establishing a PDU session with the terminal device through the first network slice; and if the terminal device is not registered for emergency use, rejecting the request.

[0165] (Supplementary Note 13) A program that, when executed, causes a processor in a network node to: receive a message requesting that a terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; determine whether the terminal device is registered for emergency use; establish a PDU session with the terminal device through the first network slice if the terminal device is registered for emergency use; and reject the request if the terminal device is not registered for emergency use.

[0166] (Supplementary Note 14) A computer-readable non-transient tangible recording medium storing a program that, when executed, causes a processor in a network node to perform the following: receive a message requesting that a terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; determine whether the terminal device is registered for emergency use; establish a PDU session with the terminal device through the first network slice if the terminal device is registered for emergency use; and reject the request if the terminal device is not registered for emergency use.

[0167] (Supplementary Note 15) A terminal device including a control unit and a communication unit, wherein the communication unit and the communication unit are configured to: in an emergency, send a message to a network node requesting that the terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; if the terminal device is registered for emergency use, receive from the network node a message indicating that a PDU session has been established through the first network slice; and if the terminal device is not registered for emergency use, receive from the network node a message indicating that the request is rejected.

[0168] (Supplementary Note 16) The terminal device described in Supplementary Note 15, wherein the control unit and the communication unit are further configured to, under normal circumstances, receive a message from the network node requesting that the terminal device use the first network slice, and receive a message from the network node indicating that the request is rejected.

[0169] (Supplementary Note 17) The terminal device described in Supplementary Note 15, wherein the control unit and the communication unit are further configured to, under normal circumstances, receive a message from the network node requesting that the terminal device use the first network slice, and receive a message from the network node indicating that the first network slice has been registered.

[0170] (Supplementary Note 18) A method executed by a terminal device, comprising: in an emergency, transmitting to a network node a message requesting that the terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; if the terminal device is registered for emergency use, receiving from the network node a message indicating that a PDU session has been established through the first network slice; and if the terminal device is not registered for emergency use, receiving from the network node a message indicating rejection of the request.

[0171] (Supplementary Note 19) A program that, when executed, causes a processor in a terminal device to: send a message to a network node requesting that the terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; if the terminal device is registered for emergency use, receive a message from the network node indicating that a PDU session has been established through the first network slice; and if the terminal device is not registered for emergency use, receive a message from the network node indicating rejection of the request.

[0172] (Supplementary Note 20) A computer-readable non-transient tangible recording medium storing a program that, when executed, causes a processor in a terminal device to perform the following: sending a message to a network node requesting that the terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; if the terminal device is registered for emergency use, receiving a message from the network node indicating that a PDU session has been established through the first network slice; and if the terminal device is not registered for emergency use, receiving a message from the network node indicating rejection of the request.

[0173] The disclosures of the above prior art documents and references are incorporated herein by reference.

[0174] 10 Network node, 101 Processor, 102 Memory, 103 Transceiver, 110 Control unit, 120 Communication unit, 20 Terminal device, 201 Processor, 202 Memory, 203 Input / output interface, 204 Transceiver, 205 Antenna, 210 Control unit, 220 Communication unit, 30 RAN node, 40 DN

Claims

1. A network node including a control unit and a communication unit, wherein the communication unit is configured to receive a message requesting that a terminal device use a first network slice in an emergency, the first network slice being a network slice allocated for emergency use, and the control unit is configured to: in an emergency, determine whether the terminal device is registered for emergency use, establish a PDU session with the terminal device through the first network slice if the terminal device is registered for emergency use, and reject the request if the terminal device is not registered for emergency use.

2. The network node according to claim 1, wherein the communication unit is further configured to receive a message requesting that the terminal device use the first network slice under normal circumstances, and the control unit is further configured to reject the request under normal circumstances.

3. The network node described in claim 1, wherein the communication unit is further configured to receive a message requesting that the terminal device use the first network slice under normal circumstances, and the control unit is further configured to register the first network slice under normal circumstances.

4. The network node according to claim 3, wherein the control unit is further configured to disconnect the PDU session established during normal times.

5. The network node of claim 1, wherein: when the terminal device normally uses a second network slice not allocated for emergency use, the communication unit is further configured to receive a message requesting that the terminal device switch from the second network slice to the first network slice in an emergency; and the control unit is further configured to disconnect a PDU session established with the terminal device through the second network slice in an emergency.

6. The network node according to claim 1, wherein a group including a plurality of terminal devices is registered with the first network slice, and the communication unit is further configured to receive a message requesting that each of the group use the first network slice in an emergency.

7. The network node according to claim 6, wherein the communication unit is further configured to send a message to each of the group requesting the use of the first network slice.

8. The network node of claim 1, wherein the control unit is further configured to determine whether the terminal device is registered for emergency use based on an identifier of the terminal device.

9. The network node of claim 1, wherein the control unit is further configured to determine whether the terminal device is registered for emergency use based on subscription data.

10. The network node of claim 1, wherein the control unit is further configured to: determine, in an emergency, service requirements of the network in an area where a disaster occurs; and select the first network slice from among network slices allocated for emergency use based on the service requirements.

11. The network node according to claim 10, wherein the control unit is further configured to: calculate the number of terminal devices registered for emergency use that are present within the area; and determine the service requirements based on the number of terminal devices.

12. A method executed by a network node, comprising: in an emergency, receiving a message requesting that a terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; determining whether the terminal device is registered for emergency use; if the terminal device is registered for emergency use, establishing a PDU session with the terminal device through the first network slice; and if the terminal device is not registered for emergency use, rejecting the request.

13. A program that, when executed, causes a processor in a network node to: receive a message requesting that a terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; determine whether the terminal device is registered for emergency use; establish a PDU session with the terminal device through the first network slice if the terminal device is registered for emergency use; and reject the request if the terminal device is not registered for emergency use.

14. A terminal device including a control unit and a communication unit, wherein the communication unit is configured to: in an emergency, send a message to a network node requesting that the terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; if the terminal device is registered for emergency use, receive from the network node a message indicating that a PDU session has been established through the first network slice; and if the terminal device is not registered for emergency use, receive from the network node a message indicating that the request is rejected.

15. The terminal device described in claim 14, wherein the control unit and the communication unit are further configured to: normally receive from the network node a message requesting that the terminal device use the first network slice; and normally receive from the network node a message indicating that the request is rejected.

16. The terminal device described in claim 14, wherein the control unit and the communication unit are further configured to: normally receive from the network node a message requesting that the terminal device use the first network slice; and receive from the network node a message indicating that the first network slice has been registered.

17. A method executed by a terminal device, comprising: in an emergency, transmitting to a network node a message requesting that the terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; if the terminal device is registered for emergency use, receiving from the network node a message indicating that a PDU session has been established through the first network slice; and if the terminal device is not registered for emergency use, receiving from the network node a message indicating rejection of the request.

18. A program that, when executed, causes a processor in a terminal device to: send a message to a network node requesting that the terminal device use a first network slice, the first network slice being a network slice allocated for emergency use; if the terminal device is registered for emergency use, receive a message from the network node indicating that a PDU session has been established through the first network slice; and if the terminal device is not registered for emergency use, receive a message from the network node indicating rejection of the request.

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