Processing device, network node, and control method for flexible operation of network slice

Abstract

This processing device functioning as an application function (AF): acquires identification information of a terminal device from the terminal device; transmits, to a network node in a core network of a cellular communication system, the identification information of the terminal device, an identifier of a first network slice being allocated to communication that is executed by the terminal device, and specific information for specifying one or more second network slices for requesting allocation to the communication; and receives, from the network node, a response indicating whether or not a change of the network slice being allocated to the communication from the first network slice to one of said one or more second network slices is permitted. In response to permission of the change, the network slice being allocated to the communication is changed.

Description

Processing device, network node, and control method for flexible operation of network slices

[0001] The present invention relates to a technology that enables flexible operation of network slices.

[0002] Known methods of using network slices include a single-slice method in which one network slice is assigned to one terminal device, and a multi-slice method in which multiple network slices are assigned, for example, for each application or communication category. In addition, URSP (UE Route Selection Policy) is known as a mechanism for supporting the use of different network slices in multi-slice according to the communication category associated with an application. The core network notifies the terminal device of a URSP rule, and the terminal device can select an appropriate network slice by comparing an explicit request from the application with the URSP rule.

[0003] When URSP is used, a network slice is selected that corresponds to the network slice selection mechanism and is intended only for communication of an application that explicitly requests the use of a network slice. In contrast, a default network slice may be assigned to a terminal device that does not correspond to the network slice selection mechanism or to communication of an application that does not explicitly request the use of a network slice. In other words, it may be assumed that an appropriate network slice cannot be assigned to a specific terminal device or application.

[0004] The present invention provides a technology that enables flexible allocation of network slices to communications of various terminal devices and applications.

[0005] A processing device according to one aspect of the present invention is a processing device that functions as an AF (Application Function), and includes: an acquisition means for acquiring identification information of a terminal device from the terminal device; a transmission means for transmitting to a network node in a core network of a cellular communication system the identification information of the terminal device, an identifier of a first network slice assigned to communication performed by the terminal device, and specific information identifying one or more second network slices requesting allocation to the communication; and a receiving means for receiving from the network node a response indicating whether a change of the network slice assigned to the communication from the first network slice to any of the one or more second network slices is permitted; and the network slice assigned to the communication is changed in response to the change being permitted.

[0006] A network node according to one aspect of the present invention is a network node in a core network of a cellular communication system, and includes: an acquisition means for acquiring, from an Application Function (AF), identification information of the terminal device, an identifier of a first network slice assigned to communication performed by the terminal device, and specific information identifying one or more second network slices requesting allocation to the communication; a determination means for determining whether to allow a change of the network slice assigned to the communication from the first network slice to any of the one or more second network slices; a transmission means for transmitting a response indicating the result of the determination to the AF; and an execution means for executing processing to change the network slice assigned to the communication in response to allowing the change.

[0007] According to the present invention, network slices can be flexibly allocated to communications of various terminal devices and applications.

[0008] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals.

[0009] The accompanying drawings are included in and constitute a part of the specification, illustrate embodiments of the present invention, and together with the description, are used to explain the principles of the present invention. FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. FIG. 2 is a diagram illustrating an example of a processing flow when an AF requests a change of a network slice. FIG. 3 is a diagram illustrating an example of a processing flow when an AF requests a change of a network slice. FIG. 4 is a diagram illustrating an example of a processing flow for determining whether a network slice can be moved. FIG. 5 is a diagram illustrating an example of a processing flow for determining whether a network slice can be moved. FIG. 6A is a diagram illustrating an example of a pre-setting of a combination of a source slice and a destination slice. FIG. 6B is a diagram illustrating an example of a pre-setting of a combination of a source slice and a destination slice. FIG. 7 is a diagram illustrating an example of a processing flow when an AF requests a change of a network slice. FIG. 8 is a diagram illustrating an example of a processing flow when an AF requests a change of a network slice. FIG. 9 is a diagram illustrating an example of a processing flow when an AF requests a change of a network slice. FIG. 10 is a diagram illustrating an example of the hardware configuration of a processing device and a network node. FIG. 11 is a diagram illustrating an example of the functional configuration of a processing device. FIG. 12 is a diagram illustrating an example of the functional configuration of a network node.

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. Furthermore, the same reference numerals are used to designate identical or similar components, and redundant descriptions will be omitted.

[0011] (System Configuration) FIG. 1 shows an example configuration of a wireless communication system according to this embodiment. The wireless communication system of FIG. 1 is, for example, a cellular wireless communication system conforming to the 5th generation (5G) standard of the 3rd Generation Partnership Project (3GPP (registered trademark)) or its successor standard. The wireless communication system is configured to provide wireless communication services to, for example, a terminal device (User Equipment). In this embodiment, this terminal device is referred to as UE 101. The UE 101 can communicate with an application server 105 via, for example, a RAN 102, a UPF 103, and a DN 104. Here, RAN represents a Radio Access Network, UPF represents a User Plane Function, and DN represents a Data Network. The UPF 103 is a function of a core network of the cellular communication system, and the DN 104 is a network outside the core network. A gateway exists between the UPF 103 and the DN 104, but is not shown here. The core network further includes functions such as the AMF 106, the SMF 107, the PCF 108, and the NEF 109. Here, AMF represents the Access and Mobility Management Function, the SMF represents the Session Management Function, the PCF represents the Policy Control Function, and the NEF represents the Network Exposure Function. Note that the core network also includes functions other than these, but these are not shown here for simplicity. Each function in the core network may be implemented by a separate network node. However, this is not limited to this, and multiple functions may be aggregated and implemented in a single network node. The application server 105 can access the core network via the NEF 109. Note that the application provided by the application server 105 is also called an Application Function (AF).

[0012] The UE (101) may support, for example, URSP (UE Route Selection Policy) and explicitly request the use of a network slice in communication with an AF. The URSP associates, for example, applications installed on the UE (101) or communication content executed by the UE (101) with a network slice in advance, and the UE (101) requests the use of an explicit network slice according to the application to be executed, the content of the communication, etc., when performing communication. For example, a video distribution application is pre-associated with a slice for video distribution, and a game application is pre-associated with a slice for game use, respectively, and when communication of these applications is executed, the use of the corresponding slice is requested. Then, when the network side accepts this request, an appropriate network slice is set for communication of these applications. Furthermore, a default network slice is set for communication different from the communication of these applications. Note that the URSP setting is determined, for example, by a network operator, and the setting is notified to the UE (101), for example, at the time of initial registration of the UE (101).

[0013] In this way, the communication performed by the UE (101) can use a network slice explicitly requested, for example, by using a URSP, depending on the application and content of the communication. On the other hand, currently, an appropriate network slice is not selected and assigned to the communication of the UE (101) at the initiative of the application server (105). That is, for example, if the UE (101) does not support the slice selection mechanism using a URSP or if a network slice corresponding to the application being executed is not predefined, a default network slice is assigned to the communication even if a more appropriate network slice is available. Furthermore, for example, it is not possible to offer a higher quality communication environment to the user while communication for a specific application is being performed.

[0014] In view of the above circumstances, the present embodiment provides a procedure that enables the application server 105 to set a network slice to be allocated to communication of the UE 101 at its initiative. Hereinafter, the application server 105 will be referred to as the AF.

[0015] (Processing Flow) In this embodiment, for example, the AF requests a network node such as the PCF 108 or the AMF 106 via the NEF 109 to change the network slice allocated to the UE's communication. For example, the AF transmits a request to the network node, the request including the UE's identification information, an identifier of the first network slice (source slice) before the change for the UE's communication, and specific information identifying one or more candidates for the second network slice (post-movement slice) to be used by the UE after the change. Then, in response to the network node permitting the change of the network slice, the network node switches the network slice by changing the session, for example, according to the procedure described in Section 4.3.3.2 of 3GPP TS 23.502 V18.3.0. This allows a network slice suitable for the UE's communication to be set in response to the AF's request. That is, for example, even in the case of communication of an application not defined by the URSP policy or when the UE (101) does not support the slice selection mechanism, the AF side can specify a network slice suitable for the application in advance, so that a network slice suitable for the communication of the application can be set. Note that the network node that receives the request does not necessarily have to accept the request, and may reject it depending on the situation.

[0016] 2 shows an example of a processing flow when an AF requests a change of a network slice according to this embodiment. For example, the AF starts cooperation by having UE 101 execute a predetermined application, and acquires identification information of the UE 101 (S201). Here, the identification information of the UE 101 is, for example, a combination of the UE 101's IP (Internet Protocol) address, DNN (Data Network Name), and S-NSSAI (Single-Network Slice Selection Assistance Information). That is, the AF may acquire, as the identification information of the UE 101, information specific to the session established for communication of the application of the UE 101. Furthermore, the identification information of the UE 101 may be a UE ID (User Equipment Identifier). In this case, the UE (101) is identified, but the session is not distinguished. The AF determines, for example, whether the network slice used in communication with the UE (101) is a network slice (e.g., a default network slice) that is not suitable for the application executed with the UE (101). Note that, in a case where an application not defined by the URSP policy is provided, a default network slice is assigned to all communications of that application, and therefore the AF may always perform the following processing assuming that a change of the network slice is necessary.

[0017] When a change in the network slice is necessary, the AF transmits information indicating a request for a change in the network slice to the NEF (S202). Since there is currently no interface for transmitting such information, the information is transmitted using a newly defined interface. This information includes, for example, the identification information of the UE (101) acquired in S201, the identifier of the source network slice, and the identifier of the post-movement network slice. As described above, the identification information of the UE (101) may be a combination of the IP address, DNN, and S-NSSAI of the UE (101), or may be a UE ID. The source network slice indicates the network slice allocated for the communication of the UE (101). Based on the recognition of the AF, the source network slice may not necessarily match the network slice actually allocated when the information of S202 is transmitted. The post-movement network slice indicates a candidate network slice requested to be allocated to the communication of the UE (101). There may be more than one candidate network slice after the movement. That is, the AF may transmit identifiers of multiple network slices to the NEF 109 as the identifier of the network slice after movement. The AF may also transmit identification information that identifies itself to the NEF 109. This is used, for example, when the NEF 109 notifies the AF of the result of the determination of whether or not the network slice can be moved thereafter. However, if the AF is uniquely identified by some procedure, explicit transmission of the AF's identifier may be omitted.

[0018] The NEF 109 forwards the received information to the PCF 108 (S203). Note that, when the NEF 109 receives the AF identifier, it does not have to forward the identifier to the PCF 108. However, this is just an example, and the NEF 109 may also forward the AF identifier to the PCF 108. Note that, since no interface for transferring this information currently exists, this information is transmitted using a newly defined interface. Upon receiving this information, the PCF 108 determines whether to permit a change in the network slice assigned to the communication of the UE 101 (S204). Then, the PCF 108 notifies the AF of the result of this determination via the NEF 109 (S205, S206). If this determination indicates that the change in the network slice is permitted, the network slice is switched by changing the session, for example, according to the procedure described in Section 4.3.3.2 of TS23.502. For example, PCF 108 changes the existing session to a session corresponding to the changed network slice by initiating processing according to procedure 1b shown in Figure 4.3.3.2-1 of Section 4.3.3.2 of TS23.502.

[0019] Note that, although FIG. 2 illustrates an example in which the PCF 108 determines whether or not the network slice can be changed, this determination may be performed by another function, such as the AMF 106. FIG. 3 illustrates an example of a processing flow in which the AMF 106 makes this determination. The processing in FIG. 3 differs from the processing in FIG. 2 in that the PCF 108 forwards the received information to the AMF 106 (S301), and the AMF 106 determines whether or not the network slice can be changed based on the information (S302), and transmits the result to the AF, for example, via the PCF 108 (S303). In this way, the determination of whether or not the network slice can be changed may be performed by the PCF 108 or the AMF 106. Furthermore, this determination may be performed by another function, or a new function for making this determination may be defined. In this case, when the network slice change is permitted, the network slice is changed by changing the session, for example, according to the procedure described in Section 4.3.3.2 of TS23.502. For example, AMF106 changes the existing session to a session corresponding to the changed network slice by initiating processing according to procedure 1h shown in Figure 4.3.3.2-1 in Section 4.3.3.2 of TS23.502.

[0020] Next, an example of a procedure for determining whether or not the above-mentioned network slice can be changed will be described with reference to Figures 4 and 5. These processes are executed by, for example, a network node that implements the PCF 108 or the AMF 106.

[0021] In FIG. 4, the network node first determines whether UE 101 has a session with the source network slice (S401). That is, the network node determines whether the network slice notified as the source network slice is associated with a session for UE 101's communication. Furthermore, if the identification information of UE 101 is a combination of an IP address, a DNN, and an S-NSSAI, it determines whether a session individually identified by this combination exists, and further determines whether the source network slice is assigned to that session. Note that, if the identification information of UE 101 is a combination of an IP address, a DNN, and an S-NSSAI, even if there are multiple sessions to which the same network slice is assigned, it is possible to identify which of those sessions is the target of the network slice change request. If the network node determines that UE 101 has a session with the source network slice (YES in S401), it then determines whether the session allows a network slice change (S402). That is, it is confirmed whether the session is set to not allow a network slice change. For example, for a voice call session, a setting may be made so that a change in the network slice is not permitted, and this determination may be made to prevent a change in the network slice for such a session. Then, when the network node determines that a session held by UE (101) permits a change in the network slice (YES in S402), it determines whether UE (101) can use the network slice designated as the network slice after the movement (S403). When the network node determines that UE (101) can use the network slice designated as the network slice after the movement (YES in S403), it determines to permit a change in the network slice for the communication of UE (101) (S404).On the other hand, if the network node determines that UE101 does not have a session with the network slice from which the UE is moving (NO in S401), if it determines that the session does not allow the network slice to be changed (NO in S402), or if UE101 cannot use the network slice specified as the network slice after the move (NO in S403), it determines not to allow the network slice for the UE101's communication to be changed (S405).

[0022] For example, when a PDU (Protocol Data Unit) session is established, a setting may be made to determine whether the session accepts a change in the network slice initiated by the network side (e.g., an AF). A value (flag) indicating this setting may be held, for example, in the PCF 108. The determination of S402 described above may be made based on this setting. In this case, when the AMF 106 executes the determination process, the AMF 106 may inquire of the PCF 108 about the setting information held therein. Even when the AMF 106 executes the determination process, the determination of S402 may be made by the PCF 108. In this case, if the PCF 108 determines that the session does not allow a change in the network slice, the PCF 108 may determine not to allow the change without notifying the AMF 106 of the information (S301) and may notify the AF of the determination result via the NEF 109. On the other hand, when the PCF 108 determines that the session allows the network slice change, it may perform the information notification of S301. In this case, the AMF 106 may omit the determination of S402. This is because the information notification of S301 to the AMF 106 allows the session to identify that the network slice change is allowed, and therefore the AMF 106 does not need to perform this determination. The PCF 108 may explicitly notify the AMF 106 of the determination result, or may implicitly notify the AMF 106 depending on whether or not the information notification of S301 is performed. The determination of whether the UE 101 has a session with the source network slice (S401) may also be performed by the PCF 108. These are merely examples, and for example, a value indicating whether or not the session accepts the network slice change may be held in a function different from the PCF 108. Furthermore, the allocation of the determination process between the AMF 106 and the PCF 108 may be changed in another format.

[0023] 4 is an example, and a determination may be made based on additional conditions in addition to these determination criteria. That is, the network node may allow the change of the network slice only on the condition that the UE (101) has a session with the source network slice, the session allows the change of the network slice, and the UE (101) can use the network slice after the move, or an additional condition may be required for the change of the network slice.

[0024] FIG. 5 shows an example of the flow of another determination process. The determination process of FIG. 5 may be used together with the determination process of FIG. 4. That is, when it is determined in the determination process of FIG. 4 that the UE 101 can use the network slice designated as the network slice after the movement (YES in S403), the determination process of FIG. 5 may be continued without proceeding to S404. Alternatively, only the determination process of FIG. 5 may be performed. In FIG. 5, a network node determines whether a combination of a source network slice and a destination network slice is a preset combination (S501). Then, the network node permits only changes within the preset combination (YES in S501) (S502), and does not permit any other combinations (NO in S501) (S503). Here, an example of preset combinations is shown in FIG. 6A. For example, in FIG. 6A, when the source network slice is a default network slice, only "Gaming A," "Gaming B," and "Video A" are permitted as destination network slices. Furthermore, when the source network slice is "Slice A," only "Gaming A" and "Gaming B" are permitted as the network slice after the move. As an example, when the source network slice is "Slice A" and the destination network slice is specified as "Video A," the network node rejects the change of the network slice. On the other hand, when the source network slice is the default network slice and the destination network slice is specified as "Video A," the network node allows the change of the network slice. Note that the network node may make a determination based on additional conditions in addition to the determination in FIG. 5.

[0025] 4 and 5, for example, when there are multiple candidates for a network slice after the move, it may be determined that the network slice change is possible if a change to any of the candidates is permitted. For example, in the determination of S403, the network node determines whether the UE (101) can use any of the multiple candidates for the network slice after the move. Then, the network node may decide to permit the slice change if the UE (101) can use any of the multiple candidates for the network slice after the move. On the other hand, if the UE (101) cannot use any of the multiple candidates for the network slice after the move, the network node may decide not to permit the slice change. Furthermore, in the determination of S501, the network node may determine whether each combination of the source network slice and the multiple candidates for the network slice after the move is a preset combination. Then, the network node may decide to permit the slice change if the combination of the source network slice and any of the multiple candidates for the network slice after the move is a preset combination. On the other hand, the network node may decide not to allow the slice change if all of the multiple candidate combinations of the source network slice and the destination network slice are not pre-configured combinations.

[0026] In the above description, an example of a processing flow in which the AF notifies the identifiers of one or more candidate network slices after the movement has been described. However, the AF may transmit a group of network slices after the movement corresponding to multiple candidate network slices after the movement to the NEF 109. FIG. 7 shows an example of a processing flow in this case. The AF transmits information indicating the group of network slices after the movement to the NEF 109 instead of the identifier of the network slice after the movement (S701). When the NEF 109 receives the information indicating the group of network slices, it performs mapping from the group to the identifier of the network slice (S702). That is, the NEF 109 retains information associating the group with the identifier of the network slice, and identifies the identifier of the corresponding network slice from the group information. The NEF 109 may identify the identifier of one of the network slices included in the group, or may identify the identifier of all of the network slices included in the group. Then, the NEF 109 may convert the group information into a network slice identifier and transfer the information from the AF to the PCF 108 (S702). Subsequent processing may be performed in the same manner as in, for example, Figures 2 and 3.

[0027] Note that the mapping from a group to a network slice identifier may be performed by a function other than the NEF 109. For example, as shown in FIG. 8, this mapping may be performed in the PCF 108 (S802). In this case, the group information received from the AF may be transferred as is from the NEF 109 to the PCF 108 (S801). Also, as shown in FIG. 9, this mapping may be performed in the AMF 106 (S902). In this case, the group information received from the AF may also be transferred as is from the PCF 108 to the AMF 106 (S901). Note that a group may include only one post-movement network slice candidate, or may include two or more post-movement network slice candidates. When multiple post-movement network slice candidates are included in a group, as described above, it may be determined that a network slice change is possible if a change to any of the candidates is permitted in the determination processes of FIGS. 4 and 5. Note that in the determination process of FIG. 5, it may be determined whether the source network slice and the post-movement network slice group are a preset combination. In this case, for example, in the pre-setting, a network slice from which the network is moved is associated with a group including one or more candidates for the network slice after the move, as shown in Fig. 6B . When this processing is performed, the above-described mapping may not be performed, and after determining that the change of the network slice is permitted, a processing may be performed to select the network slice after the change from within the group.

[0028] As described above, the network slice can be changed at the initiative of the AF. This makes it possible, for example, to allocate a network slice suitable for a type of application that is not predefined in the URSP policy, even for that application's communication. Furthermore, for example, while the UE (101) is communicating using a predetermined network slice corresponding to a predetermined application, the AF can offer the use of a network slice corresponding to a higher quality environment. In this case, for example, the AF can present to the user of the UE (101) that a higher quality network slice is available for an additional fee, and if the user approves, the AF can request a change of the network slice.

[0029] (Device Configuration) FIG. 10 shows an example hardware configuration of a processing device (e.g., functioning as an AF) that requests a change in network slice, and a network node (e.g., functioning as a PCF 108 or AMF 106) that responds to the request. In one example, the processing device and network node include a processor 1001, a ROM 1002, a RAM 1003, a storage device 1004, and a communication circuit 1005. The processor 1001 is a computer that includes one or more processing circuits, such as a general-purpose CPU (central processing unit) or an ASIC (application-specific integrated circuit), and performs the overall processing of the device and each of the above-mentioned processes by reading and executing programs stored in the ROM 1002 or the storage device 1004. The ROM 1002 is a read-only memory that stores information such as programs and various parameters related to the processing performed by the processing device and network node. The RAM 1003 functions as a workspace when the processor 1001 executes a program, and is a random access memory that stores temporary information. The storage device 1004 is configured, for example, by a removable external storage device. The communication circuit 1005 is configured, for example, by a circuit capable of communication with a core network in a 5G core or its successor standard. Note that, although one communication circuit 1005 is illustrated in FIG. 10 , the processing device and the network node may have multiple communication circuits.

[0030] FIG. 11 is a diagram showing an example of the functional configuration of a processing device (functioning as, for example, an AF). The processing device includes, for example, a communication unit 1101, a slice change request unit 1102, and a response receiving unit 1103. Note that these functions can be implemented, for example, by the processor 1001 executing a program stored in the ROM 1002 or the storage device 1004. However, this is just an example, and the functions of FIG. 11 may be realized by other configurations. Also, the functions shown in FIG. 11 are just an example, and the various control processes described above may be realized by functional units other than these. Note that the detailed operation of each functional unit has been described above, so it will not be repeated here, and only a rough functional configuration will be described.

[0031] The communication unit 1101 communicates with the UE 101, for example, via the RAN 102, the UPF 103, and the DN 104. The communication unit 1101 transmits and receives application data through communication with the UE 101. Furthermore, the communication unit 1101 can acquire, for example, identification information of the UE 101 (e.g., a combination of an IP address, a DNN, and an S-NSSAI, or a UE ID) through communication with the UE 101. The slice change request unit 1102 transmits information including the identification information of the UE 101, an identifier of the source network slice, and specific information identifying one or more candidates for the network slice after movement (e.g., information indicating the respective identifiers or groups of the one or more candidates) to the NEF 109, and requests a change of the network slice assigned to the communication of the UE 101. The response receiving unit 1103 receives, from the NEF 109, a response including a determination result as to whether the request by the slice change request unit 1102 is permitted.

[0032] FIG. 12 is a diagram illustrating an example of the functional configuration of a network node (functioning, for example, as the PCF 108 or the AMF 106). The network node includes, for example, a request receiving unit 1201, a change permission determining unit 1202, a determination result notifying unit 1203, and a slice change processing unit 1204. Note that these functions can be implemented, for example, by the processor 1001 executing a program stored in the ROM 1002 or the storage device 1004. However, this is just an example, and the functions of FIG. 12 may be realized by other configurations. Also, the functions illustrated in FIG. 12 are just an example, and the various control processes described above may be realized by functional units other than these. Note that the detailed operation of each functional unit is as described above, so it will not be repeated here, and only a rough functional configuration will be described.

[0033] The request receiving unit 1201 receives a request to change the network slice assigned to the communication of the UE 101 from the processing device (functioning as an AF) via the NEF 109. The change permission determining unit 1202 determines whether to permit the change of the network slice assigned to the communication of the UE 101 based on the information included in the change request. The determination result notifying unit 1203 notifies the processing device via the NEF 109 of the determination result by the change permission determining unit 1202, for example, in the form of a response signal to the request signal. If the change of the network slice assigned to the communication of the UE 101 is permitted, the slice change processing unit 1204 executes processing for changing the network slice. The slice change processing unit 1204 can change the network slice, for example, in accordance with the session modification procedure specified in Section 4.3.3.2 of TS23.502.

[0034] As described above, according to this embodiment, the network slice can be changed at the initiative of the AF. This makes it possible to assign a network slice suitable for an application, even for communication of a type of application not predefined in the URSP policy. This makes it possible to contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which is to "build resilient infrastructure, promote sustainable industrialization, and foster innovation."

[0035] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

[0036] This application claims priority based on Japanese Patent Application No. 2023-163023, filed on September 26, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A processing device that functions as an AF (Application Function), comprising: an acquisition means for acquiring identification information of a terminal device from the terminal device; a transmission means for transmitting, to a network node in a core network of a cellular communication system, the identification information of the terminal device, an identifier of a first network slice assigned to communication performed by the terminal device, and identification information identifying one or more second network slices requesting allocation to the communication; and a receiving means for receiving from the network node a response indicating whether or not a change of the network slice assigned to the communication from the first network slice to any of the one or more second network slices is permitted; and the network slice assigned to the communication is changed in response to the change being permitted.

2. The processing device according to claim 1, wherein the identification information of the terminal device is a combination of the IP (Internet Protocol) address, DNN (Data Network Name), and S-NSSAI (Single-Network Slice Selection Assistance Information) of the terminal device.

3. The processing device according to claim 1, wherein the identification information of the terminal device is a UE ID (User Equipment Identifier).

4. The processing device according to claim 1, wherein the specific information is information indicating a group of the one or more second network slices.

5. The processing device according to claim 1, wherein the specific information is an identifier of each of the one or more second network slices.

6. A network node in a core network of a cellular communication system, comprising: an acquisition means for acquiring, from an AF (Application Function), identification information of a terminal device, an identifier of a first network slice assigned to communication performed by the terminal device, and specific information identifying one or more second network slices requesting allocation to the communication; a determination means for determining whether to allow a change of the network slice assigned to the communication from the first network slice to any of the one or more second network slices; a transmission means for transmitting a response indicating the result of the determination to the AF; and an execution means for executing a process to change the network slice assigned to the communication in response to allowing the change.

7. The network node according to claim 6, wherein the network node is a PCF (Policy Control Function), the acquiring means acquires information from the AF via a NEF (Network Exposure Function), and the transmitting means transmits the response to the AF via the NEF.

8. The network node according to claim 6, wherein the network node is an AMF (Access and Mobility Management Function), the acquiring means acquires information from the AF via a NEF (Network Exposure Function) and a PCF (Policy Control Function), and the transmitting means transmits the response to the AF via the PCF and the NEF.

9. The network node of claim 6, wherein the identification information of the terminal device is a combination of the IP (Internet Protocol) address, DNN (Data Network Name), and S-NSSAI (Single-Network Slice Selection Assistance Information) of the terminal device.

10. The network node according to claim 6, wherein the identification information of the terminal device is a UE ID (User Equipment Identifier).

11. A network node as described in claim 6, wherein the determination means determines to allow the change on the condition that the terminal device has a session with the first network slice, the session allows the change of the network slice, and any of the one or more second network slices is available.

12. The network node of claim 6, wherein the specific information is information indicating a group of the one or more second network slices, and the determination means determines not to allow the change if the identifier of the first network slice and the group of the one or more second network slices are not a predetermined combination.

13. The network node of claim 6, wherein the specific information is information indicating respective identifiers of the one or more second network slices, and the determination means determines not to allow the change when the identifier of the first network slice and any of the one or more second network slices are not a predetermined combination.

14. A control method executed by a processing device functioning as an AF (Application Function), comprising: acquiring identification information of a terminal device from the terminal device; transmitting to a network node in a core network of a cellular communication system the identification information of the terminal device, an identifier of a first network slice assigned to communication performed by the terminal device, and specific information identifying one or more second network slices requested to be assigned to the communication; and receiving from the network node a response indicating whether a change of the network slice assigned to the communication from the first network slice to any of the one or more second network slices is permitted; and the network slice assigned to the communication is changed in response to the change being permitted.

15. A control method executed by a network node in a core network of a cellular communication system, comprising: acquiring, from an AF (Application Function), identification information of a terminal device, an identifier of a first network slice assigned to communication performed by the terminal device, and specific information identifying one or more second network slices requesting allocation to the communication; determining whether to allow a change of the network slice assigned to the communication from the first network slice to any of the one or more second network slices; sending a response indicating the result of the determination to the AF; and executing a process to change the network slice assigned to the communication in response to allowing the change.

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