Network node, and method and program involving network node

Abstract

This network node comprises a control unit and a communication unit. The communication unit is configured to receive a message requesting that a network slice used by a terminal device be switched from a first network slice to a second network slice. The control unit is configured to determine whether a predefined condition is satisfied, and switch the network slice from the first network slice to the second network slice when the condition is satisfied.

Description

Network node, method and program using the network node CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from Japanese Patent Application No. 2024-041940, filed on March 18, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a network node, a method by the network node, and a program, and in particular to a network node, a method by the network node, and a program for reserving a network slice and switching to the reserved network slice.

[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 28.531 V18.3.0 (2023-09)

[0006] Non-Patent Document 1 describes a network slice reservation procedure. In the network slice reservation procedure described in Non-Patent Document 1, a network slice subnet management service provider reserves resources at the time of provisioning.

[0007] Non-patent document 1 only describes reserving resources corresponding to a network slice subnet during provisioning, but does not describe reserving a used network slice and switching to the reserved network slice.

[0008] The present disclosure provides a technique for reserving a used network slice and switching to the reserved network slice.

[0009] In order to achieve the above object, a network node according to 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 network slice used by a terminal device be switched from a first network slice to a second network slice, and the control unit is configured to determine whether a predefined condition is met, and when the condition is met, switch the network slice from the first network slice to the second network slice.

[0010] Further, a method according to an embodiment is a method executed by a network node, and includes receiving a message requesting that a network slice used by a terminal device be switched from a first network slice to a second network slice, determining whether a predefined condition is met, and, when the condition is met, switching the network slice from the first network slice to the second network slice.

[0011] According to the above configuration, it is possible to ensure the use of the network slices that are in use. Note that the above configuration may provide 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. 2 is a block diagram showing the physical configuration of a network node according to the first embodiment. 3 is a block diagram showing the logical configuration of a network node according to the first embodiment. 4 is a block diagram showing the physical configuration of a terminal device according to the first embodiment. 5 is a block diagram showing the logical configuration of a terminal device according to the first embodiment. 6 is a diagram showing an overview of a network slice according to the first embodiment. 7 is a flowchart showing a registration procedure according to the first embodiment. 8 is a flowchart showing a procedure for switching a network slice according to the first embodiment. 9 is a flowchart showing a procedure for reserving a network slice according to the first embodiment. 10 is a diagram showing reservation data according to the first embodiment. 11 is a flowchart showing a procedure for switching a network slice according to the first embodiment. 12 is a flowchart showing a procedure for reserving a network slice according to the second embodiment. 13 is a diagram showing reservation data according to the second embodiment. 14 is a flowchart showing a procedure for switching a network slice according to the second embodiment. 15 is a flowchart showing a procedure for switching a network slice according to the third 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 / registered in the UDM / UDR 10c as subscription data.

[0050] Next, the AMF 10a notifies the terminal device 20 of the registered S-NSSAI (step S704). 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 Network Slice Reservation Non-Patent Document 1 describes a network slice reservation procedure. In the network slice reservation procedure, a network slice subnet management service provider reserves resources at the time of provisioning.

[0053] For example, a case may be considered in which AF10d requests to switch network slices to meet service requirements for an application it manages. Switching network slices refers to disconnecting the PDU session of the network slice currently being used by the terminal device 20, selecting an alternative network slice, and establishing a new PDU session for the alternative network slice. Hereinafter, the currently used network slice is referred to as the "first network slice," and the alternative network slice is referred to as the "second network slice."

[0054] In the case of switching network slices, for example, the NSSF 10e selects a second network slice in response to a request from the AF 10d. Then, the SMF 10f disconnects the PDU session for the first network slice and establishes a PDU session for the second network slice. In this manner, the network slice is switched from the first network slice to the second network slice. An example of a procedure for switching network slices will be described with reference to FIG. 8.

[0055] The AF 10d sends a network slice replacement request (Network Slice Switch Request) to the NSSF 10e / SMF 10f (step S801).

[0056] Next, the NSSF 10e selects a second network slice (step S802) by selecting one of the S-NSSAIs registered in the UDM / UDR 10c.

[0057] Next, the SMF 10f disconnects the PDU session established for the first network slice (step S803). Next, the SMF 10f establishes a PDU session for the second network slice selected in step S802 (step S804). In this way, the network slice is switched from the first network slice to the second network slice.

[0058] The network slice can be switched by the procedure described with reference to Fig. 8. By selecting the second network slice specified by the AF 10d, it is possible to satisfy, for example, requirements for the service provided by the AF 10d.

[0059] In the above case, the second network slice specified by AF 10d is selected, but when AF 10d specifies the second network slice, such a network slice may not be available. For example, it is possible that all of the network slices that satisfy the service requirements requested by AF 10d are already in use.

[0060] In this embodiment, a network slice is reserved, and when specified conditions are met, the reserved network slice is switched to. By reserving a network slice and switching to the reserved network slice when the conditions are met, the use of the specified network slice can be ensured. Note that in this embodiment, the terms "Network Slice Selection," "Network Slice Replacement," and "Network Slice Switch" are used interchangeably.

[0061] In this embodiment, the AF 10d reserves a specific network slice. The reserved network slice corresponds to a second network slice. For the reserved network slice, a corresponding S-NSSAI is registered in the UDM / UDR 10c. The network slice reservation procedure will be described with reference to FIG. 9.

[0062] First, the AF 10d sends a reservation request message to the PCF 10g using an API service via the NEF 10h (step S901). The reservation request message includes data indicating a switching condition. The switching condition includes a condition that triggers switching from the first network slice to the reserved second network slice.

[0063] The switching condition may include, for example, a condition that a specified date / time is reached. When the switching condition includes the above-mentioned condition, when the specified date / time is reached, the network slice is switched from the first network slice to the second network slice. Whether the specified date / time is reached is determined, for example, by the PCF 10g measuring a timer.

[0064] The switching condition may include, for example, a condition that the resource amount / proportion for the reserved network slice exceeds / falls below a specified resource amount / proportion. If the switching condition includes the above-mentioned condition, when the reserved network slice exceeds / falls below a specified resource amount / proportion (e.g., when the utilization rate falls below XX%), the network slice is switched from the first network slice to the second network slice. Whether the reserved network slice exceeds / falls below the specified resource amount / proportion is determined, for example, by OAM (Operation and Maintenance) monitoring resources.

[0065] The switching condition may include, for example, a condition that the terminal device 20 using the reserved network slice enters / exits a specific area. If the switching condition includes the above-mentioned condition, when the terminal device 20 enters / exits the specific area, the network slice is switched from the first network slice to the second network slice. Whether the terminal device 20 enters / exits the specific area is determined, for example, by the AMF 10a monitoring the location of the terminal device 20.

[0066] The switching condition may include, for example, a condition that the number of terminal devices 20 using the reserved network slice exceeds / falls below a specified number. When the switching condition includes the above-mentioned condition, when the number of terminal devices 20 using the reserved network slice exceeds / falls below the specified number, the network slice is switched from the first network slice to the second network slice. Whether the number of terminal devices 20 using the reserved network slice exceeds / falls below the specified number is determined, for example, by calculating the number of Allowed S-NSSAIs registered by the AMF 10a in the UDM / UDR 10c.

[0067] The switching condition may include, for example, a condition that the communication volume in the reserved network slice exceeds / falls below a specified communication volume. When the switching condition includes the above-mentioned condition, when the communication volume in the reserved network slice exceeds / falls below a specified communication volume (e.g., the communication volume exceeds YY gigabytes), the network slice is switched from the first network slice to the second network slice. Whether the communication volume in the reserved network slice exceeds / falls below a specified communication volume is determined, for example, by the UPF 10b and / or the SMF 10f monitoring user data traffic.

[0068] The above-mentioned switching conditions are merely examples and may include other conditions related to the reserved network slice, and the switching conditions may include any combination of the above-mentioned conditions and other conditions.

[0069] The reservation request message transmitted from the AF 10d in step S901 may include an S-NSSAI. This S-NSSAI is an S-NSSAI corresponding to the network slice to be reserved by the AF 10d. In other words, when the reservation request message includes an S-NSSAI, the AF 10d specifies the network slice to be reserved by itself.

[0070] Furthermore, the reservation request message transmitted from the AF 10d in step S901 may include an identifier (UE-ID) of the terminal device 20. The identifier is an identifier for the terminal device 20 managed by the AF 10d. As will be described later, when an S-NSSAI is registered as subscription data corresponding to the reservation request message, it is registered in association with the identifier of the terminal device 20.

[0071] Furthermore, the reservation request message sent from the AF 10d in step S901 may include a transaction ID. The transaction ID is used, for example, to identify the transaction of the reservation request. For example, the transaction ID is used when canceling the reservation request. The transaction ID may include a value assigned by the NEF 10h, etc.

[0072] Next, the PCF 10g selects the UDM / UDR 10c and registers the S-NSSAI corresponding to the reserved network slice in the selected UDM / UDR 10c (step S902). This S-NSSAI corresponds to the S-NSSAI included in the reservation request message sent from the AF 10d in step S901.

[0073] The S-NSSAI may be registered in the UDM / UDR 10c as subscription data. In this case, it is registered in association with the identifier (UE-ID) of the terminal device 20 included in the reservation request message transmitted from the AF 10d in step S901. The S-NSSAI may also be registered in the UDM / UDR 10c in any format other than subscription data.

[0074] Next, the PCF 10g notifies the AF 10d of the reserved S-NSSAI (step S903). This S-NSSAI is called a Reserved S-NSSAI. The Reserved S-NSSAI may also be notified to the terminal device 20. In this case, the Reserved S-NSSAI is notified to all of the terminal devices 20 managed by the AF 10d.

[0075] In this embodiment, the Reserved S-NSSAI is registered as subscription data in association with the identifier (UE-ID) of the terminal device 20. A new data type that defines data related to the Reserved S-NSSAI is added to the subscription data.

[0076] The data type newly added to the subscription data is data related to the reserved network slice. As shown in FIG. 10 , the data type is, for example, reservation data.

[0077] The reservation data includes three data fields. The first data field is an S-NSSAI. The second data field is a condition for switching network slices. The third data field is a transaction ID.

[0078] The S-NSSAI indicates the S-NSSAI corresponding to the reserved network slice, i.e., the Reserved S-NSSAI. The S-NSSAI included in the reservation data is set to the S-NSSAI included in the reservation request message transmitted from the AF 10d in step S901.

[0079] The network slice switching condition indicates a condition that triggers switching from the first network slice to the reserved second network slice. The network slice switching condition included in the reservation data is set to data indicating the switching condition included in the reservation request message transmitted from AF 10d in step S901.

[0080] The transaction ID indicates an identifier for the transaction of the reservation request. The transaction ID included in the reservation data is set to the transaction ID included in the reservation request message sent from the AF 10d in step S901.

[0081] The data structure of the reservation data is merely an example, and data structures other than those described may be adopted. In particular, the network slice switching conditions described with reference to FIG. 10 are merely an example, and the network slice switching conditions may have various values, such as numerical values ​​corresponding to the conditions.

[0082] When the Reserved S-NSSAI is registered in the UDM / UDR 10c, the reservation data is stored together as subscription data. That is, the reservation data shown in Fig. 10 is registered in the UDM / UDR 10c for each terminal device 20 or each group of terminal devices 20. In this embodiment, the reservation data is registered in response to a request from the AF 10d that manages the terminal device 20. Therefore, when the AF 10d manages multiple terminal devices 20, the reservation data for the multiple terminal devices 20 is registered collectively.

[0083] The subscription data is registered and managed for each terminal device 20. Alternatively, the subscription data may be registered and managed for each network slice or for each combination of a terminal device 20 and a network slice.

[0084] 9, the reservation data is registered in response to a request from the AF 10d, but the format is not limited to this. For example, in step S901, the terminal device 20 may transmit a reservation request message to the PCF 10g via the AMF 10a.

[0085] Next, a procedure for performing network slice switching according to this embodiment will be described with reference to Figure 11. In this embodiment, when a network slice switching condition is satisfied, a first network slice is switched to a second network slice. The second network slice is a network slice corresponding to the S-NSSAI included in the reservation data shown in Figure 10. Hereinafter, in the figure, the network slice is referred to as "NW-S."

[0086] First, the PCF 10g determines whether the network slice switching condition is satisfied (step S1101). The process of step S1101 is repeated until the network slice switching condition is satisfied. Whether the network slice switching condition is satisfied is determined according to the data indicated by the network slice switching condition included in the reservation data shown in FIG. 10.

[0087] The reservation data is acquired together with the subscription data based on the identifier (UE-ID) of the terminal device 20. Note that the subscription data may be acquired based on a second S-NSSAI instead of the identifier of the terminal device 20. The subscription data may also be acquired based on a combination of the UE-ID and the S-NSSAI for the first network slice. The identifier and S-NSSAI of the terminal device 20 are included in the reservation request message in the network slice reservation procedure described with reference to FIG. 9. Therefore, the identifier and S-NSSAI of the terminal device 20 may be stored in the PCF 10g in the network slice reservation procedure.

[0088] As described above, the network slice switching conditions include a condition that a specified date / time is reached and a condition that the terminal device 20 enters / exits a specific area. Regarding the condition that a specified date / time is reached, for example, the PCF 10g may determine whether the specified date / time is reached at a certain timing. Regarding the condition that the terminal device 20 enters / exits a specific area, the PCF 10g may request the AMF 10a to monitor whether the terminal device 20 has entered / exited a specific area at a certain timing. Furthermore, in response to the AMF 10a detecting that the terminal device 20 has entered / exited a specific area, the PCF 10g may receive a notification indicating this from the AMF 10a.

[0089] If it is determined in step S1101 that the network slice switching condition is satisfied, the PCF 10g uses the API service via the NEF 10h to send a notification message indicating that the network slice switching will be performed to the AF 10d (step S1102). Note that the PCF 10g may wait for a response from the AF 10d before proceeding to step S1103, which will be described later.

[0090] Next, the PCF 10g instructs the NSSF 10e to select a second network slice (step S1103). The second network slice is selected in accordance with the S-NSSAI included in the reservation data.

[0091] In step S1104, the NSSF 10e selects a second network slice by selecting an S-NSSAI from among the S-NSSAIs registered in the UDM / UDR 10c.

[0092] Next, the SMF 10f disconnects the PDU session established for the first network slice (step S1105). The PDU session established for the first network slice refers to the PDU session established for the terminal device 20 managed by the AF 10d that reserved the second network slice.

[0093] Next, the SMF 10f establishes a PDU session for the second network slice selected in step S1104 (step S1106). The PDU session is established for the terminal device 20 whose PDU session was disconnected in step S1105.

[0094] The above-described procedures for disconnecting and establishing a PDU session are performed by the NSSF 10e, the AMF 10a, and the SMF 10f in cooperation with each other. This also applies to other embodiments described later. In this manner, a network-controlled network slice selection is performed, and the network slice is switched from the first network slice to the second network slice.

[0095] As described above, the first embodiment has been described. In the first embodiment, a network slice is reserved, and in response to a specified condition being satisfied, the network slice is switched from a first network slice to a second network slice.

[0096] It should be noted that the order of steps shown in Fig. 11 is merely an example, and the steps may be executed in an order other than that shown in Fig. 11. Furthermore, some of the steps shown in Fig. 11 may be omitted, and other steps may be added.

[0097] According to the first embodiment, if a specified network slice is not immediately available, the use of such a network slice can be ensured.

[0098] In the first embodiment, the network slice reservation and the network slice switching are performed by the PCF 10g, but the fact that the PCF 10g is the executing entity is merely an example. The procedure described in the first embodiment is performed by one or more of the network nodes 10.

[0099] 2. Second Embodiment Next, a second embodiment will be described. In the first embodiment, an example in which the AF 10d specifies a network slice to be reserved is described. In the second embodiment, an example in which the AF 10d specifies requested service requirements and / or network slice use, and the NSSF 10e selects a network slice that satisfies the service requirements and / or use is described.

[0100] A network slice reservation procedure according to the second embodiment will be described with reference to Fig. 12. The network slice reservation procedure according to the second embodiment is generally similar to the network slice reservation procedure described with reference to Fig. 9, but the data included in the reservation request message transmitted from the AF 10d is different.

[0101] First, the AF 10d sends a reservation request message to the PCF 10g using the API service via the NEF 10h (step S1201). The reservation request message includes an identifier (UE-ID) of the terminal device 20, data indicating a network slice switching condition, and a transaction ID, as described in the first embodiment.

[0102] The reservation request message transmitted from the AF 10d may also include data indicating requested service requirements. The requested service requirements indicate service requirements requested for the second network slice to be reserved. The requested service requirements indicate, for example, a QoS value requested for each QoS parameter. The technical specifications defined by 3GPP define the QoS parameters shown in Table 1. The requested service requirements may have a combination of a value indicating a type of QoS parameter and a value indicating a corresponding QoS value, such as "1: packet delay budget" and "10 (ms)."

[0103] Furthermore, the reservation request message sent from the AF 10d may include data indicating a network slice usage. The network slice usage indicates the usage of a network slice identified by a standard SST or a combination of a standard SST and an individual SST.

[0104] Next, the PCF 10g selects the UDM / UDR 10c and registers reservation data for the reserved network slice in the selected UDM / UDR 10c (step S1202). Next, the PCF 10g sends a notification message to the AF 10d indicating that the network slice has been reserved (step S1203).

[0105] In the second embodiment, the reservation request message transmitted from AF 10d does not include S-NSSAI. Therefore, in step S1202, S-NSSAI is not registered, and reservation data may be registered in association with requested service requirements and / or network slice usage.

[0106] Alternatively, in step S1202, a network slice that satisfies the requested service requirements and / or network slice application may be selected. In this case, reservation data is registered by associating an S-NSSAI corresponding to the selected network slice. A method for selecting a network slice is described in the network slice switching procedure with reference to FIG. 14, as will be described later.

[0107] Reservation data according to the second embodiment will be described with reference to Fig. 13. The reservation data according to the second embodiment is also registered in the UDM / UDR 10c as subscription data in the network slice reservation procedure described with reference to Fig. 12.

[0108] The reservation data includes three data fields. The first data field is Demanded Service Requirements. The second data field is Network Slice Application. The third data field is Network Slice Switching Conditions. The fourth data field is a Transaction ID. The Network Slice Switching Conditions and the Transaction ID are the same as those described in the first embodiment, and therefore detailed description thereof will be omitted.

[0109] The requested service requirements indicate service requirements requested for the second network slice to be reserved. The requested service requirements included in the reservation data are set to data indicating the requested service requirements included in the reservation request message transmitted from AF 10d in step S1201.

[0110] The network slice use indicates the use of the second network slice to be reserved. The network slice use included in the reservation data is set to data indicating the network slice use included in the reservation request message transmitted from AF 10d in step S1201.

[0111] In the second embodiment, reservation data including requested service requirements is registered in the UDM / UDR 10c. In this state, network slice switching is performed. The procedure for performing network slice switching according to the second embodiment will be described with reference to FIG. 14.

[0112] First, the PCF 10g instructs the NSSF 10e to select a second network slice (step S1401).

[0113] In step S1402, the NSSF 10e selects a second network slice. The second network slice is selected from among network slices that satisfy the requested service requirements included in the reservation data shown in FIG. 13 and / or correspond to the network slice usage included in the reservation data.

[0114] The reservation data is acquired together with the subscription data based on an identifier (UE-ID) of the terminal device 20. Note that the subscription data may be acquired based on a second S-NSSAI instead of the identifier of the terminal device 20. Also, the subscription data may be acquired based on a combination of the UE-ID and the S-NSSAI for the first network slice.

[0115] To select a second network slice that satisfies the requested service requirements, QoS values ​​corresponding to the QoS provided by each of the network slices 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 2 shows an example of the QoS list.

[0116] Furthermore, in order to select a second network slice corresponding to a specified network slice use, a value indicating the use of each network slice may be stored in the UDM / UDR 10c. The value indicating the use may be stored as a network slice use list in association with the S-NSSAI for each network slice. Table 3 shows an example of the network slice use list.

[0117] By storing the QoS list in the UDM / UDR 10c, a second network slice that satisfies the requested service requirements can be appropriately selected. Similarly, by storing the network slice usage list in the UDM / UDR 10c, a second network slice that corresponds to a specified network slice usage can be appropriately selected.

[0118] Next, the PCF 10g determines whether the network slice switching condition is satisfied for the network slice selected in step S1402 (step S1403). The process of step S1403 is repeated until the network slice switching condition is satisfied. Whether the network slice switching condition is satisfied is determined according to the data indicated by the network slice switching condition included in the reservation data shown in FIG. 13.

[0119] If it is determined in step S1403 that the network slice switching condition is satisfied, the PCF 10g uses the API service via the NEF 10h to send a notification message indicating that the network slice switching will be performed to the AF 10d (step S1404). Note that the PCF 10g may wait for a response from the AF 10d before proceeding to step S1405, which will be described later.

[0120] Next, the SMF 10f disconnects the PDU session established for the first network slice (step S1405). The PDU session established for the first network slice refers to the PDU session established for the terminal device 20 managed by the AF 10d that reserved the second network slice.

[0121] Next, the SMF 10f establishes a PDU session for the second network slice selected in step S1402 (step S1406). The PDU session is established for the terminal device 20 whose PDU session was disconnected in step S1405. In this manner, network-controlled network slice selection is performed, and the network slice is switched from the first network slice to the second network slice.

[0122] It should be noted that the order of steps shown in Fig. 14 is merely an example, and the steps may be executed in an order other than that shown in Fig. 14. Furthermore, some of the steps shown in Fig. 14 may be omitted, and other steps may be added.

[0123] The second embodiment has been described above. In the second embodiment, a network slice is reserved and, in response to a specified condition being satisfied, the network slice is switched from a first network slice to a second network slice. In addition, in the second embodiment, a network slice that satisfies a requested service requirement and / or corresponds to a specified network slice use is selected.

[0124] According to the second embodiment, when a network slice that satisfies the requested service requirements and / or corresponds to the specified network slice use is not immediately available, the use of such a network slice can be ensured. Also, according to the second embodiment, the requested network slice can be selected by simply specifying the requested service requirements and / or the network slice use without specifying a specific network slice.

[0125] 3. Third Embodiment Next, a third embodiment will be described. In the first and second embodiments, an example was described in which a network slice is switched from a first network slice to a second network slice for a specific application. If a terminal device 20 using the second network slice exists at the time of switching the network slice from the first network slice to the second network slice, the PDU session established for the terminal device 20 needs to be disconnected.

[0126] For a terminal device 20 using the second network slice, it may be undesirable for the PDU session being used to be disconnected without any notification. In the third embodiment, an example will be described in which a terminal device 20 using the second network slice is present.

[0127] A procedure for performing network slice switching according to the third embodiment will be described with reference to Fig. 15. The network slice switching procedure according to the third embodiment includes additional steps in addition to the network slice switching procedure described with reference to Fig. 11.

[0128] The PCF 10g determines whether the network slice switching condition is satisfied (step S1501). The process of step S1501 is repeated until the network slice switching condition is satisfied. Details of the determination of whether the network slice switching condition is satisfied are as described above.

[0129] If it is determined in step S1501 that the network slice switching condition is satisfied, the PCF 10g uses the API service via the NEF 10h to send a notification message indicating that the network slice switching will be performed to the AF 10d (step S1502). Note that the PCF 10g may wait for a response from the AF 10d before proceeding to step S1503, which will be described later.

[0130] Next, the PCF 10g instructs the NSSF 10e to select a second network slice (step S1503). The second network slice is selected in accordance with the S-NSSAI included in the reservation data.

[0131] In step S1504, the NSSF 10e selects a second network slice by selecting an S-NSSAI from among the S-NSSAIs registered in the UDM / UDR 10c.

[0132] Next, the PCF 10g determines whether or not there is a terminal device 20 using the second network slice selected in step S1504 (step S1505). The determination of whether or not there is a terminal device 20 using the second network slice is performed by referring to the subscription data. Specifically, the determination is performed by determining whether an Allowed S-NSSAI or a Subscribed S-NSSAI corresponding to the second network slice is registered.

[0133] In step S1505, if there is a terminal device 20 using the second network slice, the PCF 10g sends a notification message to the terminal device 20 indicating that network slice switching will be performed or that the PDU session will be disconnected (step S1506).

[0134] After transmitting the notification message, the PCF 10g may transition to subsequent processing in response to receiving an acknowledgement (ACK) from the terminal device 20. In this case, for example, if a negative acknowledgement (NACK) is received from the terminal device 20 or if no acknowledgement is received from the terminal device 20, the PCF 10g may interrupt the processing. Alternatively, the PCF 10g may return to step S1503 and instruct the NSSF 10e to select another second network slice.

[0135] Alternatively, the PCF 10g may transition to the subsequent process after a predefined time has elapsed after receiving the confirmation response from the terminal device 20. The predefined time may be registered in the subscription data for the terminal device 20, for example.

[0136] Next, the SMF 10f disconnects the PDU session established for the second network slice (step S1507). The PDU session established for the second network slice refers to the PDU session established for the terminal device 20 determined to be using the second network slice in step S1505.

[0137] Next, the SMF 10f disconnects the PDU session established for the first network slice (step S1508). The PDU session established for the first network slice refers to the PDU session established for the terminal device 20 managed by the AF 10d that reserved the second network slice.

[0138] Next, the SMF 10f establishes a PDU session for the second network slice selected in step S1104 (step S1509). The PDU session is established for the terminal device 20 whose PDU session was disconnected in step S1508. In this manner, network-controlled network slice selection is performed, and the network slice is switched from the first network slice to the second network slice.

[0139] It should be noted that the order of steps shown in Fig. 15 is merely an example, and the steps may be executed in an order other than that shown in Fig. 11. Furthermore, some of the steps shown in Fig. 15 may be omitted, and other steps may be added.

[0140] The third embodiment has been described above. In the third embodiment, a network slice is reserved, and in response to the specified conditions being satisfied, the network slice is switched from a first network slice to a second network slice. Furthermore, in the third embodiment, when the network slice is switched, the terminal device 20 using the second network slice is notified that the network slice will be switched.

[0141] According to the third embodiment, when a specified network slice is not immediately available, the use of such a network slice can be ensured. Furthermore, according to the third embodiment, it is possible to prevent a terminal device 20 using a second network slice from unexpectedly disconnecting a PDU session when switching the network slice.

[0142] As described above, the network slice switching procedure described with reference to Figure 15 includes additional steps in addition to the network slice switching procedure described with reference to Figure 11. Alternatively, the network slice switching procedure may include additional steps in addition to the network slice switching procedure described with reference to Figure 14. That is, in the network slice switching procedure according to the third embodiment, the AF 10d may specify requested service requirements, and the NSSF 10e may select a network slice that satisfies the service requirements.

[0143] 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.

[0144] 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).

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] (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 network slice used by a terminal device be switched from a first network slice to a second network slice, and the control unit is configured to: determine whether a predefined condition is met, and when the condition is met, switch the network slice from the first network slice to the second network slice.

[0150] (Supplementary Note 2) The network node according to Supplementary Note 1, wherein the message indicates reserving the second network slice.

[0151] (Supplementary Note 3) The network node according to Supplementary Note 1 or 2, wherein the condition includes a specified date / time being reached.

[0152] (Supplementary Note 4) The network node according to any one of Supplementary Notes 1 to 3, wherein the condition includes that a resource amount / proportion for the second network slice is greater than / less than a specified resource amount / proportion.

[0153] (Supplementary Note 5) The network node according to any one of Supplementary Notes 1 to 4, wherein the condition includes a terminal device using the second network slice entering / leaving a specific area.

[0154] (Supplementary Note 6) The network node according to any one of Supplementary Notes 1 to 5, wherein the condition includes that the number of terminal devices using the second network slice is greater than / less than a specified number.

[0155] (Supplementary Note 7) The network node according to any one of Supplementary Notes 1 to 6, wherein the condition includes that a communication volume in the second network slice is greater than / less than a specified communication volume.

[0156] (Supplementary Note 8) The network node according to any one of Supplementary Notes 1 to 7, wherein the message includes an S-NSSAI corresponding to the second network slice, and the control unit is further configured to select the second network slice based on the S-NSSAI.

[0157] (Supplementary Note 9) The network node according to any one of Supplementary Notes 1 to 7, wherein the message includes data indicating requested service requirements, and the control unit is further configured to select the second network slice based on the service requirements.

[0158] (Supplementary Note 10) The network node according to any one of Supplementary Notes 1 to 7 and 9, wherein the message includes data indicating a use of the network slice, and the control unit is further configured to select the second network slice based on the use.

[0159] (Supplementary Note 11) The network node according to any one of Supplementary Notes 1 to 10, wherein the communication unit is further configured to receive a message requesting switching a network slice used by a plurality of terminal devices from a first network slice to a second network slice.

[0160] (Supplementary Note 12) The network node according to Supplementary Note 11, wherein the communication unit is further configured to receive the message from an Application Function (AF), the AF managing the plurality of terminal devices.

[0161] (Supplementary Note 13) A network node described in any one of Supplementary Notes 1 to 12, wherein the control unit is further configured to determine whether or not there is a terminal device using the second network slice, and the communication unit is further configured to send a notification message to the terminal device using the second network slice indicating that the network slice is to be switched from the first network slice to the second network slice.

[0162] (Supplementary Note 14) The network node described in Supplementary Note 13, wherein the communication unit is further configured to receive an acknowledgment response to the notification message from the terminal device, and the control unit is further configured to switch the network slice from the first network slice to the second network slice by disconnecting a PDU session established with the terminal device using the second network slice in response to receiving the acknowledgment response.

[0163] (Supplementary Note 15) The network node according to Supplementary Note 13 or 14, wherein the control unit is further configured to interrupt switching of the network slice from the first network slice to the second network slice when the communication unit does not receive an acknowledgment response to the notification message from the terminal device or receives a negative response to the notification message from the terminal device.

[0164] (Supplementary Note 16) The network node according to Supplementary Note 13 or 14, wherein the control unit is further configured to interrupt switching the network slice from the first network slice to the second network slice after a predefined time has elapsed if the communication unit does not receive an acknowledgment for the notification message from the terminal device or receives a negative acknowledgment for the notification message from the terminal device.

[0165] (Supplementary Note 17) A method executed by a network node, comprising: receiving a message requesting switching a network slice used by a terminal device from a first network slice to a second network slice; determining whether a predefined condition is met; and, when the condition is met, switching the network slice from the first network slice to the second network slice.

[0166] (Supplementary Note 18) A program that, when executed, causes a processor in a network node to: receive a message requesting that a network slice used by a terminal device be switched from a first network slice to a second network slice; determine whether a predefined condition is met; and, when the condition is met, switch the network slice from the first network slice to the second network slice.

[0167] (Supplementary Note 19) A computer-readable non-transient tangible recording medium storing a program that, when executed, causes a processor in a network node to: receive a message requesting that a network slice used by a terminal device be switched from a first network slice to a second network slice; determine whether a predefined condition is met; and, when the condition is met, switch the network slice from the first network slice to the second network slice.

[0168] (Supplementary Note 20) A terminal device including a control unit and a communication unit, wherein the control unit and the communication unit are configured to send a message to a network node requesting that a network slice used by the terminal device be switched from a first network slice to a second network slice, and the network slice is switched from the first network slice to the second network slice by the network node when a predefined condition is satisfied.

[0169] The disclosures of the above prior art documents and references are incorporated herein by reference.

[0170] 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 network slice used by a terminal device be switched from a first network slice to a second network slice, and the control unit is configured to: determine whether a predefined condition is met; and when the condition is met, switch the network slice from the first network slice to the second network slice.

2. The network node of claim 1, wherein the message indicates reserving the second network slice.

3. The network node of claim 1, wherein the condition includes reaching a specified date / time.

4. The network node of claim 1, wherein the condition includes a resource amount / percentage for the second network slice being above / below a specified resource amount / percentage.

5. The network node according to claim 1, wherein the condition includes a terminal device using the second network slice entering / leaving a specific area.

6. The network node according to claim 1, wherein the condition includes that the number of terminal devices using the second network slice is greater than / less than a specified number.

7. The network node of claim 1, wherein the condition includes that the traffic volume in the second network slice is above / below a specified traffic volume.

8. The network node according to claim 1, wherein the message includes an S-NSSAI corresponding to the second network slice, and the control unit is further configured to select the second network slice based on the S-NSSAI.

9. The network node according to claim 1, wherein the message includes data indicating requested service requirements, and the control unit is further configured to select the second network slice based on the service requirements.

10. The network node of claim 1, wherein the message includes data indicating a use of the network slice, and the control unit is further configured to select the second network slice based on the use.

11. The network node of claim 1, wherein the communication unit is further configured to receive a message requesting switching of a network slice used by multiple terminal devices from a first network slice to a second network slice.

12. The network node according to claim 11, wherein the communication unit is further configured to receive the message from an application function (AF), the AF managing the plurality of terminal devices.

13. The network node of claim 1, wherein the control unit is further configured to determine whether or not there is a terminal device using the second network slice, and the communication unit is further configured to send a notification message to the terminal device using the second network slice indicating that the network slice is to be switched from the first network slice to the second network slice.

14. The network node of claim 13, wherein the communication unit is further configured to receive an acknowledgment for the notification message from the terminal device, and the control unit is further configured to switch the network slice from the first network slice to the second network slice in response to receiving the acknowledgment, by disconnecting a PDU session established with the terminal device using the second network slice.

15. The network node of claim 13, wherein the control unit is further configured to interrupt switching of the network slice from the first network slice to the second network slice when the communication unit does not receive an acknowledgment for the notification message from the terminal device or receives a negative acknowledgment for the notification message from the terminal device.

16. The network node of claim 13, wherein the control unit is further configured to interrupt switching the network slice from the first network slice to the second network slice after a predefined time has elapsed if the communication unit does not receive an acknowledgment for the notification message from the terminal device or receives a negative acknowledgment for the notification message from the terminal device.

17. A method executed by a network node, comprising: receiving a message requesting that a network slice used by a terminal device be switched from a first network slice to a second network slice; determining whether a predefined condition is met; and, when the condition is met, switching the network slice from the first network slice to the second network slice.

18. A program that, when executed, causes a processor in a network node to: receive a message requesting that a network slice used by a terminal device be switched from a first network slice to a second network slice; determine whether a predefined condition is met; and, when the condition is met, switch the network slice from the first network slice to the second network slice.

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