AMF, UE, and the method thereof

Abstract

To contribute to enabling UE to easily utilize network slices supported only by sparsely located local cells.SOLUTION: An AMF receives a registration request message from UE including first information indicating that the UE supports network slices available in some of tracking areas (TAs) within the UE's registration area and second information indicating Requested NSSAI. The AMF then transmits to the UE a registration approval message including third information indicating at least one S-NSSAI included in the NSSAI regarding network slices available in some of the TAs within the UE's registration area and fourth information indicating a list of TA identities (TAIs) related to the at least one S-NSSAI included in the NSSAI.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to wireless communication networks, and more particularly to network slicing. [Background technology]

[0002] The 5G system (5GS) supports network slicing (see, for example, Non-Patent Documents 1 and 2, especially Section 5.15 of Non-Patent Document 1). Network slicing enables multiple logical networks or non-virtualized logical networks to be created on a physical network. For example, network slicing may use Network Function Virtualization (NFV) technology and software-defined networking (SDN) technology to create multiple virtualized logical networks on a physical network. Each logical network is called a network slice. A network slice provides specific network capabilities and network characteristics. A network slice instance (NSI) is defined as a set of network function (NF) instances, resources (e.g., computer processing resources, storage, and networking resources), and access networks (ANs) (Next Generation Radio Access Network (NG-RAN) and / or Non-3GPP InterWorking Function (N3IWF)) that form one network slice.

[0003] A network slice is identified by an identifier known as Single Network Slice Selection Assistance Information (S-NSSAI). S-NSSAI consists of a Slice / Service type (SST) and a Slice Differentiator (SD). SST refers to the expected network slice behaviour in terms of features and services. SD is optional information that complements SST to differentiate between multiple network slices of the same Slice / Service type.

[0004] The S-NSSAI can have standard or non-standard values. Currently, standard SST values ​​1, 2, 3, and 4 are associated with enhanced Mobile Broad Band (eMBB), Ultra Reliable and Low Latency Communication (URLLC), Massive Internet of Things (MIoT), and Vehicle to Everything (V2X) slice types. The non-standard values ​​of the S-NSSAI identify one network slice in a particular Public Land Mobile Network (PLMN). That is, the non-standard SST values ​​are PLMN-specific values ​​and are associated with the PLMN ID of the PLMN that assigned them. Each S-NSSAI ensures network isolation in terms of selecting a particular NSI. The same NSI may be selected via different S-NSSAIs. The same S-NSSAI may be associated with different NSIs. Each network slice may be uniquely identified by an S-NSSAI.

[0005] On the other hand, Network Slice Selection Assistance Information (NSSAI) refers to a set of S-NSSAIs. Therefore, at least one S-NSSAI can be included in one NSSAI. There are several types of NSSAI, which are known as Configured NSSAI, Requested NSSAI, Allowed NSSAI, Rejected NSSAI, and Pending NSSAI.

[0006] The Configured NSSAI includes at least one S-NSSAI, each applicable to at least one PLMN. The Configured NSSAI is configured by, for example, a Serving PLMN and applied to the Serving PLMN. Alternatively, the Configured NSSAI may be a Default Configured NSSAI. The Default Configured NSSAI is configured by a Home PLMN (HPLMN) and applied to any PLMNs for which a specific Configured NSSAI is not provided. The Default Configured NSSAI is provisioned to a radio terminal (User Equipment (UE)) from, for example, a Unified Data Management (UDM) of the HPLMN via an Access and Mobility Management Function (AMF).

[0007] The Requested NSSAI is signaled by the UE to the network, for example during a registration procedure, and enables the network to determine a Serving AMF, at least one network slice, and at least one NSI for the UE.

[0008] The Allowed NSSAI is provided to the UE by the Serving PLMN and indicates at least one S-NSSAI that the UE can use in the current Registration Area of ​​the Serving PLMN. The Allowed NSSAI is determined by the AMF of the Serving PLMN, e.g., during the registration procedure. Thus, the Allowed NSSAI is signaled to the UE by the network (i.e., AMF) and stored in the respective memories (e.g., non-volatile memories) of the AMF and the UE.

[0009] The Rejected NSSAI includes at least one S-NSSAI that is rejected by the current PLMN. The Rejected NSSAI may also be referred to as rejected S-NSSAIs. The S-NSSAI is rejected by the entire current PLMN or by the current registration area. If the AMF rejects any of the at least one S-NSSAI included in the Requested NSSAI, for example during the UE registration procedure, it includes them in the Rejected NSSAI. The Rejected NSSAI is signaled to the UE by the network (i.e., AMF) and stored in the respective memories of the AMF and the UE.

[0010] A Pending NSSAI indicates at least one S-NSSAI for which Network Slice-Specific Authentication and Authorization (NSSAA) is pending. The Serving PLMN must perform an NSSAA for the S-NSSAIs of the HPLMN for which an NSSAA is imposed based on the subscription information. To perform an NSSAA, the AMF invokes an Extensible Authentication Protocol (EAP)-based authorization procedure. The EAP-based authentication procedure takes a relatively long time to obtain an outcome. Therefore, the AMF determines the Allowed NSSAI as described above in the UE registration procedure, but does not include the S-NSSAIs for which an NSSAA is imposed in the Allowed NSSAI, but includes them in the Pending NSSAI instead. The Pending NSSAI is signaled to the UE by the network (i.e., AMF) and stored in the respective memories of the AMF and the UE.

[0011] The 3rd Generation Partnership Project (3GPP) will begin considering Release 17 in the first quarter of 2020. In Release 17, enhancements to network slices are expected to be considered (see, for example, Non-Patent Documents 3, 4, and 5). Non-Patent Document 3 proposes that a study is needed to support parameters included in the Generic Slice Template (GST) proposed by the GSM Association in 5GS. Non-Patent Document 4 proposes that a study is needed on a mechanism to enable User Equipment (UE) to quickly access a cell that supports an intended slice. Non-Patent Document 5 raises the issue that, according to the current 3GPP specifications, a UE must select an NG-RAN node to perform a registration procedure without knowing which NG-RAN node supports which network slice. Non-Patent Document 5 proposes that a study is needed on how to select a particular cell that can be used to access the intended network slice. [Prior art documents] [Non-patent literature]

[0012] [Non-Patent Document 1] 3GPP TS 23.501 V16.3.0 (2019-12) "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System Architecture for the 5G System (5GS); Stage 2 (Release 16)", December 2019 [Non-Patent Document 2] 3GPP TS 23.502 V16.3.0 (2019-12) "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Procedures for the 5G System (5GS); Stage 2 (Release 16)", December 2019

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

[0013] According to the current 3GPP specifications, an NG-RAN node informs the Access and Mobility management Function (AMF) in the 5G Core Network (5GC) of the network slices supported by the NG-RAN node. More specifically, the NG-RAN node provides the Supported TA List Information Element (IE) and the TAI Slice Support List IE to the AMF in the procedure of setting up the application level configuration data required to interwork with the AMF over the control plane interface (i.e., N2 (or NG-C) interface). The Supported TA List IE indicates the Tracking Areas (TAs) supported in the NG-RAN node. The TAI Slice Support List IE is included in the Supported TA List IE and indicates the supported S-NSSAIs per TA (or Tracking Area Identity (TAI)). The Single Network Slice Selection Assistance Information (S-NSSAI) is an identifier of the network slice. Thus, the AMF knows the TAs supported by the NG-RAN node on which the N2 interface is established and knows the S-NSSAIs supported for each TA supported by the NG-RAN node.

[0014] Furthermore, according to current 3GPP specifications, all S-NSSAIs included in the Allowed NSSAI must be available in all TAs that make up the registration area. A registration area of ​​a UE is a list of at least one TA (TAI). From the UE's perspective, the network slices allowed for the UE are homogeneously supported at least in the registration area indicated by the AMF.

[0015] The inventors have conducted a study on network slicing and found various issues. In one of them, a use case is assumed in which a network slice (e.g., S-NSSAI #2) for a specific communication service (e.g., URLLC) is provided in cells in a high frequency band (e.g., mmWave, 28 GHz). However, considering the propagation characteristics of mmWave, the cells in the high frequency band may be local cells that are patchily arranged among cells in a low frequency band (e.g., sub-6 GHz) associated with other network slices (e.g., S-NSSAI #1).

[0016] Consider the case where a UE selects a low frequency cell for a registration procedure to 5GC and requests a network slice (e.g., S-NSSAI #2) that is not supported by the NG-RAN node serving the low frequency cell. In this case, according to the current 3GPP specifications, the AMF in 5GC knows that S-NSSAI #2 is not supported in the TA to which the low frequency cell on which the UE is camped belongs, and therefore will not allow the UE to use S-NSSAI #2. If the UE then sees another cell (e.g., a high frequency cell) that does not belong to the registration area (i.e., list of TAIs) indicated by the AMF, it must reselect that cell and perform an additional registration request procedure via that cell to use the intended service (e.g., URLLC) and network slice (e.g., S-NSSIA #2).

[0017] In another issue, a case is assumed in which a Dual Connectivity (DC) Master Node (MN) does not support the network slice (e.g., S-NSSIA #2) that the UE intends to use, but a Secondary Node (SN) does. Consider the case in which a UE selects a Candidate MN for a registration procedure to 5GC and requests a network slice (e.g., S-NSSAI #2) that is not supported by the Candidate MN but is supported by the Candidate SN. Candidate MN means an NG-RAN node that can act as an MN for DC, and Candidate SN means an NG-RAN node that can act as an SN for DC. In this case, according to the current 3GPP specifications, the AMF knows that the Candidate MN does not support S-NSSAI #2 and therefore will not allow the UE to use S-NSSAI #2. If S-NSSAI #2 is only available in a specific frequency band (e.g., 28 GHz) and the specific frequency band is deployed only under the SN of the DC, the UE may not be able to use the service via S-NSSAI #2.

[0018] These issues are related to the constraint on the registration area of ​​a UE. As mentioned above, according to the current 3GPP specifications, all S-NSSAIs included in the Allowed NSSAI must be available in all TAs that make up the registration area. Relaxing this constraint may, for example, allow a UE to easily use network slices that are supported only by sparsely populated local cells.

[0019] One of the objectives to be achieved by the embodiments disclosed herein is to provide an apparatus, a method, and a program that contribute to enabling a UE to easily utilize a network slice supported only by sparsely arranged local cells. It should be noted that this objective is only one of the objectives to be achieved by the embodiments disclosed herein. Other objectives or problems and novel features will be apparent from the description of this specification or the accompanying drawings. [Means for solving the problem]

[0020] In one aspect, an AMF apparatus comprises at least one memory and at least one processor coupled to the at least one memory. The at least one processor is configured to receive a registration request message from a UE via a first access network (AN) node. The at least one processor is further configured to transmit a registration accept message to the UE via the first AN node in response to receiving the registration request message, the registration accept message indicating a registration area of ​​the UE and a first list of at least one conditionally allowed network slice identifier. The registration area is a list of at least one tracking area. Each conditionally allowed network slice identifier is not available in the entire registration area, but is available in at least one specific cell or at least one specific tracking area included in the registration area.

[0021] In one aspect, a UE comprises at least one memory and at least one processor coupled to the at least one memory. The at least one processor is configured to send a registration request message to an AMF via a first access network (AN) node. The at least one processor is further configured to receive a registration accept message from the AMF via the first AN node, the registration area indicating a registration area of ​​the UE and a first list of at least one conditionally allowed network slice identifier. The registration area is a list of at least one tracking area. Each conditionally allowed network slice identifier is not available in the entire registration area, but is available in at least one specific cell or at least one specific tracking area included in the registration area.

[0022] In one aspect, a method performed by an AMF device comprises: (a) receiving a registration request message from a UE via a first access network (AN) node; and (b) in response to receiving the registration request message, transmitting a registration accept message to the UE via the first AN node, the registration accept message indicating a registration area of ​​the UE and a first list of at least one conditionally authorized network slice identifier, the registration area being a list of at least one tracking area, each of which is not available in the entire registration area, but is available in at least one specific cell or at least one specific tracking area included in the registration area.

[0023] In one aspect, a method performed by a UE comprises: (a) sending a registration request message to an AMF via a first access network (AN) node; and (b) receiving a registration accept message from the AMF via the first AN node indicating a registration area of ​​the UE and a first list of at least one conditionally allowed network slice identifier, the registration area being a list of at least one tracking area, each conditionally allowed network slice identifier being unavailable in the entire registration area and available in at least one specific cell or at least one specific tracking area included in the registration area.

[0024] In one aspect, the program includes instructions (software code) that, when loaded into a computer, causes the computer to perform a method according to any of the above aspects. Effect of the Invention

[0025] According to the above-described aspects, it is possible to provide an apparatus, a method, and a program that contribute to enabling a UE to easily utilize a network slice supported only by sparsely deployed local cells. [Brief description of the drawings]

[0026] [Figure 1A] FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication network according to an embodiment. [Figure 1B] FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication network according to an embodiment. [Figure 2A] FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication network according to an embodiment. [Figure 2B] FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication network according to an embodiment. [Figure 3A] FIG. 13 illustrates an example of information elements included in a registration approval message according to an embodiment. [Figure 3B] FIG. 13 illustrates an example of information elements included in a registration approval message according to an embodiment. [Figure 4] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Diagram 5] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Figure 6] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Figure 7] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Figure 8] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Figure 9] 11 is a flowchart illustrating an example of the operation of a UE according to an embodiment. [Figure 10] 11 is a flowchart illustrating an example of the operation of a UE according to an embodiment. [Figure 11] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Figure 12] 11 is a flowchart illustrating an example of an AMF operation according to an embodiment. [Figure 13] 1 is a flowchart illustrating an example of an operation of an (R)AN node according to an embodiment. [Figure 14] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Figure 15] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Figure 16] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Figure 17] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Figure 18] FIG. 11 is a sequence diagram illustrating an example of signaling according to an embodiment. [Figure 19] FIG. 2 is a block diagram showing a configuration example of an (R)AN node according to an embodiment. [Figure 20] A block diagram showing an example configuration of an AMF according to an embodiment. [Figure 21] FIG. 2 is a block diagram showing an example configuration of a UE according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, specific embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and duplicated descriptions will be omitted as necessary for clarity of explanation.

[0028] The multiple aspects described below can be implemented independently or in appropriate combination. These multiple aspects have different novel features. Therefore, these multiple aspects contribute to solving different objects or problems and to achieving different effects.

[0029] The following aspects are described primarily with respect to the 3GPP fifth generation mobile communication system (5G system (5GS)). However, these aspects may be applied to other wireless communication systems that support network slicing similar to 5GS.

[0030] <First aspect> 1A and 1B show an example of a wireless communication network (i.e., 5GS) according to some aspects including the present aspect. In the example of FIG. 1A and FIG. 1B, the wireless communication network includes (Radio) Access Network ((R)AN) nodes 1 and 2, an AMF 3, and a UE 4. Each element (network function) shown in FIG. 1A and FIG. 1B can be implemented, for example, as a network element on dedicated hardware, as a software instance running on dedicated hardware, or as a virtualized function instantiated on an application platform.

[0031] (R)AN nodes 1 and 2 are deployed in an (R)AN (i.e., NG-RAN). (R)AN nodes 1 and 2 may be gNBs. (R)AN nodes 1 and 2 may be Central Units (e.g., gNB-CUs) in a cloud RAN (C-RAN) deployment. The first (R)AN node 1 terminates an interface 101 (i.e., N2 (or NG-C) interface) and interworks with an AMF 3 over the interface 101. In some implementations, the second (R)AN node 2 may also terminate a CP interface 102 (i.e., N2 (or NG-C) interface) and interwork with an AMF 3 over the interface 102. In other implementations, the second (R)AN node 2 may not have a CP interface (i.e., N2 (or NG-C) interface) with any AMF. For example, if the second (R)AN node 2 is only responsible for the SN of the DC, the second (R)AN node 2 may not have a CP interface 102 with the AMF 3.

[0032] (R)AN node 1 provides at least one cell (hereafter referred to as cell 10) with a cell coverage area 10 as its service area. (R)AN node 2 provides at least one cell (hereafter referred to as cell 20) with a cell coverage area 20 as its service area. Cell 10 operates in a different frequency band than cell 20 and supports a different network slice than cell 20. More specifically, in the example of FIGS. 1A and 1B, cell 10 operates in a first frequency band (FB-1) and supports a first network slice identifier (S-NSSAI-1). In contrast, cell 20 operates in a second frequency band (FB-2) and supports a second network slice identifier (S-NSSAI-2).

[0033] In some implementations, the frequency band FB-2 of the cell 20 may be higher than the frequency band FB-1 of the cell 10. For example, the frequency band FB-2 of the cell 20 may be a millimeter wave band (e.g., 28 GHz), and the frequency band FB-1 of the cell 10 may be sub-6 GHz. In this case, as shown in FIG. 1A and FIG. 1B, the cell 20 of the high frequency band may be a local cell (small cell) patchily arranged in the cell 10 of the low frequency band. The cell 10 may completely cover the cell 20 or may partially overlap with the cell 20. The cell 20 may be a cell constituting a Stand-alone Non-Public Network (SNPN) defined in Non-Patent Document 1, or may be a cell constituting a Public network integrated Non-Public Network (NPN).

[0034] The AMF3 is one of the network functions in the 5GC control plane. The AMF3 provides the termination of the CP interface 101 (and the CP interface 102). The AMF3 terminates a single signaling connection (i.e., N1 Non-Access Stratum (NAS) signalling connection) with the UE4 and provides registration management, connection management, and mobility management. Furthermore, the AMF3 provides NF services to NF consumers (e.g., other AMFs, Session Management Function (SMF), and Authentication Server Function (AUSF)) over a service-based interface (i.e., Namf interface). Furthermore, the AMF3 consumes NF services provided by other NFs (e.g., UDM, Network Slice Selection Function (NSSF), and Policy Control Function (PCF)).

[0035] The AMF 3 can learn the network slices (S-NSSAIs) supported by the (R)AN node 1 through the procedure for setting up the CP interface 101. Specifically, the (R)AN node 1 provides the Supported TA List IE and the TAI Slice Support List IE to the AMF 3 in the procedure for setting up the application level configuration data required for interworking with the AMF on the CP interface 101. The Supported TA List IE indicates the TAs supported in the (R)AN node 1. The TAI Slice Support List IE is included in the Supported TA List IE and indicates the supported S-NSSAIs per TA (or Tracking Area Identity (TAI)).

[0036] Similarly, the AMF 3 may be informed by the (R)AN node 2 of the list of TAs (TAIs) supported by the (R)AN node 2 and the list of supported S-NSSAIs per TA (TAI) in the procedure of setting up the CP interface 102. Alternatively, if the CP interface 102 is not set up, the AMF 3 may be informed of these lists for the (R)AN node 2 by the (R)AN node 1. Alternatively, the AMF 3 may be configured by an operator with these lists for the (R)AN node 2.

[0037] The UE 4 may communicate with the first (R)AN node 1 over the air interface in at least one cell (including cell 10) provided by the first (R)AN node 1. Additionally, the UE 4 may communicate with the second (R)AN node 2 over the air interface when the UE 4 is available in at least one cell (including cell 20) provided by the second (R)AN node 2. In some implementations, the UE 4 may communicate with the first and second (R)AN nodes 1 and 2 simultaneously to provide master cell group (MCG) and secondary cell group (SCG) dual connectivity (DC). The MCG is a group of serving cells associated with (or provided by) the first (R)AN node 1 acting as an MN for the DC, and includes an SpCell (i.e., a Primary Cell (PCell)) and optionally at least one Secondary Cell (SCell). On the other hand, the SCG is a group of serving cells associated with (or provided by) the second (R)AN node 2 acting as an SN for the DC, and includes the SCG's Primary Cell and optionally at least one Secondary Cell (SCell). The SCG's Primary Cell is the Primary SCG Cell (PSCell) or Primary Secondary Cell (PSCell). The PSCell is the SCG's Special Cell (SpCell).

[0038] In the examples of Figures 1A and 1B, cell 10 belongs to a first tracking area (TA) identified by a first TAI (TAI-1). The tracking area (TA) to which cell 20 belongs is different between Figures 1A and 1B. More specifically, in the example of Figure 1A, cell 20 belongs to a second TA different from the first TA to which cell 10 belongs. The second TA is identified by a second TAI (TAI-2). Meanwhile, in the example of Figure 1B, cell 20 belongs to the same first TA as cell 10.

[0039] According to the configuration example of FIG. 1A, the first TA and the second TA may be defined and arranged as shown in FIG. 2A. In the example of FIG. 2A, the first TA identified by the first TAI-1 may be configured by the cell 10 and its neighboring cells (e.g., cells 10-13), each of which operates in the first frequency band FB-1 and supports the first network slice identifier S-NSSAI-1. That is, the first TA (TAI-1) may be configured by a group of adjacent cells each of which supports the first network slice identifier S-NSSAI-1. In contrast, the second TA identified by the second TAI-2 may be configured by sparsely arranged small cells 20 and 21, each of which operates in the second frequency band FB-2 and supports the second network slice identifier S-NSSAI-2. That is, the second TA (TAI-2) may be configured by a group of distant cells each of which supports the second network slice identifier S-NSSAI-2.

[0040] According to the configuration example of Fig. 1B, the first TA may be defined and arranged as shown in Fig. 2B. In the example of Fig. 2B, the first TA identified by the first TAI-1 includes cells 10-13 that operate in a first frequency band FB-1 and support a first network slice identifier S-NSSAI-1, and is further configured by cells 20 and 21 that operate in a second frequency band FB-2 and support a second network slice identifier S-NSSAI-2. Thus, in the example of Fig. 2B, the first TA identified by the first TAI-1 includes multiple cells (e.g., cell 10 and cell 20) that operate in different frequency bands and support different network slices from each other.

[0041] The configurations shown in Figures 1A and 1B may be modified, for example, as follows. In the example of Figures 1A and 1B, cells 10 and 20 are provided by different (R)AN nodes 1 and 2. Alternatively, cells 10 and 20 may be provided by the same (R)AN node (e.g., (R)AN node 1). In this case, UE 4 may perform carrier aggregation of cells 10 and 20 to communicate simultaneously in cells 10 and 20.

[0042] In the following, a registration procedure according to this embodiment will be described. The 5GS registration procedure is used, for example, for initial registration and mobility registration. The initial registration is used by the UE 4 to connect to the network (5GC) after power-on. The mobility registration is used by the UE 4 when the UE 4 moves out of the registration area or when the UE 4's capabilities or other parameters negotiated in the registration procedure need to be updated.

[0043] In response to receiving a registration request message from the UE 4 via the first (R)AN node 1, the AMF 3 sends a registration approval message to the UE 4 via the first (R)AN node 1. The registration approval message indicates a registration area of ​​the UE 4. The registration area of ​​the UE 4 is a list of at least one TAs (TAIs). In addition, the registration approval message includes a list of at least one conditionally allowed network slice identifier (i.e., S-NSSAIs). Each conditionally allowed S-NSSAI is not available in the entire registration area of ​​the UE 4, but is available in at least one specific cell or at least one specific tracking area included in the registration area of ​​the UE 4. Such a list of at least one conditionally allowed S-NSSAIs may be referred to as a Conditionally Allowed NSSAI or a Conditional NSSAI.

[0044] The registration acceptance message may further include a list of Allowed NSSAIs similar to the existing Allowed NSSAIs. Specifically, the registration acceptance message may further include a list of at least one Allowed S-NSSAIs that are available to the UE 4 throughout the registration area of ​​the UE 4.

[0045] Following the examples of Figures 1A and 2A, the AMF 3 may send information elements 300 shown in Figure 3A to the UE 4 via a registration acceptance message. Specifically, the AMF 3 may include both TAI-1 and TAI-2 in the registration area 301 of the UE 4, and include both S-NSSAI-1 and S-NSSAI-2 in the Conditionally Allowed NSSAI 303 of the UE 4. In this case, the registration acceptance message may indicate at least one specific TA with which each conditionally allowed S-NSSAI is associated. As shown in Figure 3A, the S-NSSAI-1 in the Conditionally Allowed NSSAI 303 may be associated with TAI-1. This indicates that the S-NSSAI-1 is not available in the entire registration area of ​​the UE 4 (i.e., both TAI-1 and TAI-2), but is conditionally available (allowed) only in TAI-1. In a similar manner, S-NSSAI-2 in Conditionally Allowed NSSAI 303 may be associated with TAI-2, indicating that S-NSSAI-2 is not available in the entire registration area of ​​UE 4 (i.e., both TAI-1 and TAI-2) but is conditionally available (allowed) only in TAI-2.

[0046] Following the examples of Figures 1A, 2A, and 3A, when AMF3 sends a TAI list with both TAI-1 and TAI-2 as its registration areas to UE4 via a registration approval message, the S-NSSAI included in the Conditionally Allowed NSSAI for the registration area of ​​UE4 can be used only in some of the TAs that constitute the registration area.

[0047] In contrast, following the examples of Figures 1B and 2B, the AMF 3 may send information elements 320 shown in Figure 3B to the UE 4 via a registration approval message. Specifically, the AMF 3 may include only TAI-1 in the TAI list indicating the registration area 321 of the UE 4, include S-NSSAI-1 in the Allowed NSSAI 322 of the UE 4, and include S-NSSAI-2 in the Conditionally Allowed NSSAI 323 of the UE 4. In this case, the registration approval message may indicate at least one specific cell with which each conditionally allowed S-NSSAI is associated, or may indicate at least one frequency band in which at least one specific cell with which each conditionally allowed S-NSSAI is associated operates. As shown in Figure 3B, the S-NSSAI-2 in the Conditionally Allowed NSSAI 323 may be associated with a second frequency band FB-2. This indicates that S-NSSAI-2 is not available in the entire registration area of ​​UE4 (i.e., TAI-1), but is conditionally available (allowed) only in at least one specific cell operating in a specific frequency band FB-2.

[0048] According to the examples of Figures 1B, 2B, and 3B, the S-NSSAI included in the Conditionally Allowed NSSAI for the registration area of ​​UE4 is available in all TA(s) constituting the registration area. However, the S-NSSAI included in the Conditionally Allowed NSSAI is provided only in some cells (some geographical areas) in the TA included in the registration area. In other words, the S-NSSAI included in the Conditionally Allowed NSSAI is provided only in cells operating in a specific frequency band in the TA included in the registration area.

[0049] As can be understood from the above description, in this aspect, the AMF 3 sends a list of at least one conditionally authorized S-NSSAIs to the UE 4 via a registration acceptance message. Each conditionally authorized S-NSSAI is not available in the entire registration area of ​​the UE 4, but is available in at least one specific cell or at least one specific tracking area included in the registration area. This enables the UE 4 to easily utilize a network slice supported only in sparsely deployed local cells. In some implementations, in response to detecting a cell, frequency band, or TA supporting the conditionally authorized S-NSSAI (e.g., S-NSSAI-2), the UE 4 can request the core network (e.g., AMF 3) to establish or activate a protocol data unit (PDU) session associated with the conditionally authorized S-NSSAI without performing an additional registration request procedure. In some implementations, when the second (R)AN node 2 is a candidate SN responsible for DC only and does not have a CP interface with any AMF, it may be possible for the UE 4 to use services via a network slice (S-NSSAI-2) supported by the second (R)AN node 2.

[0050] 4 shows an example of a registration procedure of UE 4. In step 401, UE 4 sends a Radio Resource Control (RRC) Setup Complete message to the first (R)AN node 1. The RRC Setup Complete message includes a NAS message (registration request message) and a Requested NSSAI. UE 4 also includes a Requested NSSAI in the registration request message. The Requested NSSAI includes an S-NSSAI-1 supported by the first (R)AN node 1 and an S-NSSAI-2 supported by the second (R)AN node 2.

[0051] The first (R)AN node 1 selects an AMF3 based on the Requested NSSAI. In step 402, the first (R)AN node 1 sends a NAS message (REGISTRATION REQUEST message) to the selected AMF3 via an N2 (or NG-C) signaling message. The N2 message may be an INITIAL UE MESSAGE message. The NAS message (REGISTRATION REQUEST message) contains the Requested NSSAI, which includes S-NSSAI-1 and S-NSSAI-2.

[0052] The AMF3 may determine whether to allow the S-NSSAI-1 and S-NSSAI-2 included in the Requested NSSAI to the UE4 based on at least one Subscribed S-NSSAIs of the UE4. Specifically, the AMF3 may obtain the Subscribed S-NSSAI(s) of the UE4 from the UDM and determine whether the S-NSSAI-1 and S-NSSAI-2 or the S-NSSAIs corresponding thereto (HPLMN S-NSSAIs) are included in the Subscribed S-NSSAI(s) of the UE4. In the example of FIG. 4, the AMF3 includes the S-NSSAI-1 in the Allowed NSSAI and includes the S-NSSAI-2 in the Conditional NSSAI (Conditionally Allowed NSSAI). This example may be performed based on whether the Subscribed S-NSSAI(s) of the UE4 includes the S-NSSAI-1 and S-NSSAI-2 from the UDM. Furthermore, based on the determined Allowed NSSAI and Conditional NSSAI, the AMF 3 determines a registration area (i.e., a TAI list) of the UE 4. Specifically, the AMF 3 determines the TAs constituting the registration area of ​​the UE 4 such that all S-NSSAIs included in the Allowed NSSAI are available in all TAs in the registration area, and all S-NSSAIs included in the Conditional NSSAI are available in at least one cell or at least one TA in the registration area.

[0053] In step 403, the AMF 3 sends a NAS Registration Accept message to the UE 4 via the first (R)AN node 1. The Registration Accept message indicates the registration area (i.e., TAI list), the Allowed NSSSAI, and the Conditional NSSAI. The Registration Accept message may include other information elements, such as a Rejected NSSAI or a Pending NSSAI, or both. If the UE 4 does not have an allowed S-NSSAI, the Registration Accept message may not include the Allowed NSSAI. If the S-NSSAI(s) set as the Conditional NSSAI is also set as the Pending NSSAI, the AMF 3 may, after sending a NAS registration accept message to the UE 4 via the first (R)AN node 1 in step 403, perform a Network Slice-Specific Authentication and Authorization (NSSAA) procedure as specified in non-patent document 1 for the S-NSSAI(s) set as the Conditional NSSAI.

[0054] FIG. 5 shows another example of the registration procedure of UE4. Steps 501 and 502 are similar to steps 401 and 402 in FIG. 4. FIG. 5 relates to the case described with reference to FIG. 3A. Thus, in step 503, AMF3 includes both S-NSSAI-1 and S-NSSAI-2 in the Conditional NSSAI. S-NSSAI-1 in the Conditional NSSAI may be associated with a subset of TAIs included in the registration area of ​​UE4. Similarly, S-NSSAI-2 in the Conditional NSSAI may be associated with a subset of TAIs included in the registration area of ​​UE4. Following the example of FIG. 3A, the TAI subset associated with S-NSSAI-1 includes TAI-1, and the TAI subset associated with S-NSSAI-2 includes TAI-2.

[0055] Figure 6 shows yet another example of the registration procedure of the UE 4. Steps 601 and 602 are similar to steps 401 and 402 in Figure 4. Figure 6 relates to the case described with reference to Figure 3B. Thus, the AMF 3 includes S-NSSAI-1 in the Allowed NSSAI and S-NSSAI-2 in the Conditional NSSAI. The S-NSSAI-2 in the Conditional NSSAI may be associated with a list of at least one frequency band in which at least one specific cell in which the S-NSSAI-2 is available operates. The list may be a list of NR Absolute Radio Frequency Channel Numbers (NR-ARFCNs).

[0056] <Second aspect> The configuration example of the wireless communication network according to the present embodiment is similar to the example described with reference to Figures 1A, 1B, 2A, and 2B. This embodiment provides a specific example of the operation of the AMF 3 and the UE 4.

[0057] FIG. 7 illustrates an example of signaling according to the present embodiment. The UE 4 includes a specific indication indicating that the UE 4 supports conditional authorization of a network slice identifier (S-NSSAI) in a registration request message. The name of the specific indication may be, for example, Conditional NSSAI Support Indication or Conditional NSSAI Support Indicator. In step 701, the UE 4 sends a registration request message including the specific indication to the AMF 3. In response to detecting the specific indication from the registration request message, the AMF 3 may include at least one S-NSSAI included in the Requested NSSAI of the UE 4 in a Conditional NSSAI and send a registration accept message including the Conditional NSSAI to the UE 4. In contrast, if the registration request message received from the UE 4 does not include the above-mentioned specific indication, the AMF 3 does not set the Conditional NSSAI to the UE 4. The (R)AN node receives the registration request message shown in step 701 from the UE 4 and transmits (forwards) it to the AMF 3, but the UE 4 may transmit the above-mentioned specific indication to the (R)AN node using an RRC message. This RRC message may be an RRC Setup Request message or an RRC Setup Complete message.

[0058] According to the signaling in Fig. 7, the AMF 3 can know whether the UE 4 supports the Conditional NSSAI. Therefore, the AMF 3 can operate to set the Conditional NSSAI to the UE 4 only if the UE 4 supports the Conditional NSSAI.

[0059] <Third aspect> A configuration example of the wireless communication network according to this embodiment is similar to the example described with reference to Figures 1A, 1B, 2A, and 2B. This embodiment provides a modification of the registration procedure described with reference to Figure 6.

[0060] FIG. 8 relates to the sending of a registration acknowledgement message in step 603 of FIG. 6. In step 801, the AMF 3 sends an N2 message including a NAS message (registration acknowledgement message) to the first (R)AN node 1. The N2 message may be a DOWNLINK NAS TRANSPORT message. As described with reference to FIG. 6, the NAS message (registration acknowledgement message) includes a Conditional NSSAI. The Conditional NSSAI includes an S-NSSAI-2 and is associated with a list of at least one frequency band in which at least one specific cell in which the S-NSSAI-2 is available operates. The list includes a second frequency band FB-2 in which the cell 20 supporting the S-NSSAI-2 operates. The list may be a list of ARFCNs. The AMF 3 further includes the Conditional NSSAI in the N2 message carrying the NAS message (registration acknowledgement message). This allows the first (R)AN node 1 to know the Conditional NSSAI of the UE 4.

[0061] Based on the Conditional NSSAI of the UE4, the first (R)AN node 1 creates a configuration of inter-frequency measurement to enable the UE4 to measure the frequency band associated with the S-NSSAI included in the Conditional NSSAI. More specifically, the first (R)AN node 1 creates a configuration (e.g., measurement gap) required to measure the second frequency band FB-2 in which the cell supporting the S-NSSAI-2 in the Conditional NSSAI operates, taking into account the radio capability of the UE4 (e.g., the number of Radio Frequency (RF) chains of the UE4). In step 802, the first (R)AN node 1 transmits an RRC message including the NAS message (registration acknowledgement message) received from the AMF3 and the configuration of the inter-frequency measurement to the UE4. The RRC message may be an RRC Reconfiguration message. This allows the UE 4, when RRC_CONNECTED in the cell 10 of the first (R)AN node 1, to perform a search to find a cell in the second frequency band FB-2 that supports the S-NSSAI-2 included in the Conditional NSSAI.

[0062] <Fourth aspect> The configuration example of the wireless communication network according to this embodiment is similar to the example described with reference to Figures 1A, 1B, 2A and 2B. This embodiment provides a concrete example of the operation of the UE 4 after the registration procedure is completed.

[0063] Figure 9 shows an example of the operation of UE4. The operation shown in Figure 9 is performed by the NAS layer of UE4, or by the RRC layer and NAS layer. In step 901, UE4 detects a specific cell, frequency band, or tracking area associated with the conditionally authorized S-NSSAI (e.g., S-NSSAI-2). In other words, UE4 detects a specific cell, frequency band, or tracking area in which the conditionally authorized S-NSSAI is available.

[0064] In step 902, in response to the detection in step 901, the UE 4 (NAS layer or RRC layer) notifies the application layer that the conditionally authorized S-NSSAI is available. The application layer may be a UE application that uses a communication service (e.g., URLLC) provided via the conditionally authorized S-NSSAI. This allows the application layer to know that the conditionally authorized S-NSSAI is available. For example, if a PDU session (e.g., URLLC session) associated with the conditionally authorized S-NSSAI is needed or pending, the application layer may request the UE 4 (NAS layer or RRC layer) to establish or activate the PDU session in response to the notification in step 902. The application layer may determine whether to request the establishment or activation of the PDU session based on information on whether the UE 4 is stationary based on an acceleration sensor or the like included in the UE 4. For example, the application layer may determine to request the establishment or activation of the PDU session based on information on whether the UE 4 is stationary. When the conditional authorization S-NSSAI is provided in a high frequency band, it is possible to provide more stable communication to the UE 4 by using information on whether the UE 4 is stationary or not.

[0065] The UE 4 may notify the application layer that the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is no longer available when the UE 4 can no longer detect a particular cell, frequency band, or tracking area associated with the conditionally authorized S-NSSAI.

[0066] According to the operation of FIG. 9, the UE 4 can inform the application layer of the availability of a network slice that is supported, for example, only by sparsely populated local cells.

[0067] <Fifth aspect> The configuration example of the wireless communication network according to this embodiment is similar to the example described with reference to Figures 1A, 1B, 2A and 2B. This embodiment provides a concrete example of the operation of the UE 4 after the registration procedure is completed.

[0068] The UE 4 according to this embodiment requests the core network (5GS, AMF) to establish or activate a PDU session associated with the conditionally granted S-NSSAI only when the UE 4 detects at least one specific cell (or a specific tracking area). Figure 10 shows an example of the operation of the UE 4. The operation shown in Figure 10 is performed by the NAS layer of the UE 4, or by the RRC layer and the NAS layer.

[0069] In step 1001, the UE 4 receives a request from the application layer to establish or activate a PDU session associated with a conditionally granted S-NSSAI (eg, S-NSSAI-2).

[0070] In step 1002, the UE 4 determines the feasibility of the service associated with the conditional authorization S-NSSAI. Specifically, the UE 4 may determine whether the UE 4 detects a particular cell, frequency band, or tracking area associated with the conditional authorization S-NSSAI.

[0071] Additionally or alternatively, UE4 may determine that if UE4 is in RRC_IDLE or RRC_INACTIVE and there is no dormant (suspended, or deactivated) PDU session associated with the granted S-NSSAI (e.g., S-NSSAI-1), UE4 performs cell reselection to another cell that is provided with a conditionally granted S-NSSAI (e.g., S-NSSAI-2).

[0072] Additionally or alternatively, UE4 may decide that if UE4 is in RRC_IDLE or RRC_INACTIVE, there is an inactive PDU session associated with an authorized S-NSSAI (e.g., S-NSSAI-1), and the authorized S-NSSAI (e.g., S-NSSAI-2) is also available in another cell where the conditionally authorized S-NSSAI (e.g., S-NSSAI-1) is available, UE4 transitions to RRC_CONNCTED in the current cell and requests a handover via the current cell to a cell where the conditionally authorized S-NSSAI is available.

[0073] Additionally or alternatively, UE4 may determine that if UE4 is RRC_CONNCTED in a cell associated with an authorized S-NSSAI (e.g., S-NSSAI-1), there is an active PDU session associated with the authorized S-NSSAI, and the authorized S-NSSAI (e.g., S-NSSAI-1) is also available in another cell where a conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available, UE4 requests a handover to another cell where the conditionally authorized S-NSSAI is available.

[0074] Additionally or alternatively, the UE 4 may determine whether to move to the cell of the conditionally authorized S-NSSAI or to stay in the current cell based on the internal logic of the UE 4 if the UE 4 is in RRC_IDLE or RRC_INACTIVE, there is a dormant PDU session associated with the authorized S-NSSAI (e.g., S-NSSAI-1), and the authorized S-NSSAI (e.g., S-NSSAI-2) is unavailable in other cells where the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available. The UE 4 may determine the priority between the authorized S-NSSAI (e.g., S-NSSAI-1) and the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) by referring to the UE Route Selection Policy (URSP).

[0075] Additionally or alternatively, the UE 4 may determine whether to move to the cell of the conditionally authorized S-NSSAI or to stay in the current cell based on the internal logic of the UE 4 if the UE 4 is RRC_CONNCTED in a cell associated with the authorized S-NSSAI (e.g., S-NSSAI-1), there is an active PDU session associated with the authorized S-NSSAI, and the authorized S-NSSAI (e.g., S-NSSAI-1) is unavailable in other cells where the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available. The UE 4 may determine the priority between the authorized S-NSSAI (e.g., S-NSSAI-1) and the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) by referring to the URSP.

[0076] Additionally or alternatively, UE4 may determine that if UE4 is RRC_CONNCTED in a cell associated with an authorized S-NSSAI (e.g., S-NSSAI-1) and dual connectivity or carrier aggregation is possible between the current cell and other cells for which a conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available, UE4 requests dual connectivity or carrier aggregation.

[0077] In step 1003, the UE 4 accepts or rejects the request from the application layer based on the result of the determination in step 1002. For example, if the UE 4 decides to stay in the current cell associated with the allowed S-NSSAI (e.g., S-NSSAI-1), the UE 4 rejects the request from the application layer. When rejecting the request from the application layer, the UE 4 may notify the application layer of a reject cause (e.g., higher priority PDU sessions active) and a back-off timer value.

[0078] According to the operation of FIG. 10, the UE 4 can, for example, appropriately provide a communication service to the application layer via a network slice supported only by sparsely populated local cells.

[0079] <Sixth aspect> The configuration example of the wireless communication network according to this embodiment is similar to the example described with reference to Figures 1A, 1B, 2A, and 2B. This embodiment provides a concrete example of cell reselection performed after the UE 4 completes the registration procedure.

[0080] An example of cell reselection is shown in Figure 11. In step 1101, the UE 4 has completed the registration procedure via the cell 10 provided by the first (R)AN node 1, is allowed to use S-NSSAI-1, and is conditionally allowed to use S-NSSAI-2, i.e., the Allowed NSSAI configured by the AMF 3 includes S-NSSAI-1, and the Conditional NSSAI configured by the AMF 3 includes S-NSSAI-2.

[0081] In step 1102, the UE 4 decides to reselect the cell 20 that supports the conditional admission S-NSSAI-2. The UE 4 may decide to reselect the cell according to the operation described in the fifth aspect. The cell 20 may be provided by the second (R)AN node 2. Alternatively, as already described, the cell 20 may be provided by the first (R)AN node 1 that provides the cell 10. The UE 4 may reselect the cell 20 in step 1102 in response to an incoming call to a PDU session associated with the S-NSSAI-2. In this case, the AMF 3 transmits a Paging message including the S-NSSAI-2 to the RAN node 1. The RAN node 1 associates the S-NSSAI-2 received from the AMF 3 with the identifier of the UE 4 and performs a Paging. As a result, the UE 4 recognizes the incoming call related to the S-NSSAI-2 and reselects the cell 20.

[0082] In step 1103, the UE 4 reselects the cell 20 and performs an RRC connection establishment procedure in the cell 20. In step 1104, the UE 4 initiates a PDU session establishment procedure or a service request procedure via the cell 20 to establish or activate a PDU session associated with the conditionally allowed S-NSSAI-2. The PDU session establishment procedure is performed when the UE 4 wants to establish a new PDU session to utilize a network slice (allowed S-NSSAI) already allowed to the UE 4 by 5GC. The service request procedure is used by the UE 4 in the Connection Management (CM)-IDLE state to request the establishment of a secure connection with the AMF 3. Furthermore, the service request procedure is performed for the UE 4 in the CM-IDLE or CM-CONNECTED state to activate a user plane connection for an established PDU session.

[0083] If a PDU session associated with the conditional grant S-NSSAI-2 has not been established, the UE 4 sends a PDU Session Establishment Request message to the AMF 3 via the cell 20. More specifically, the UE 4 sends a NAS message (e.g., a UL NAS Transport message) carrying an N1 SM container (PDU Session Establishment Request) to the AMF 3. If a PDU session associated with the conditional grant S-NSSAI-2 has been established, the UE 4 sends a Service Request message to the AMF 3 via the cell 20.

[0084] After the communication via the PDU session associated with the conditionally granted S-NSSAI-2 is terminated, the UE 4 may perform cell reselection from the cell 20 supporting the conditionally granted S-NSSAI-2 back to the cell 10 supporting the authorized S-NSSAI-1. The UE 4 may remain in the cell 10 supporting the authorized S-NSSAI-1 (or any other cell) until a new connection to the conditionally granted S-NSSAI-2 is requested by the application layer.

[0085] <Seventh aspect> A configuration example of a wireless communication network according to this embodiment is similar to the example described with reference to Figures 1A, 1B, 2A, and 2B. This embodiment provides an example of network controlled mobility between a cell 10 supporting an authorization S-NSSAI-1 and a cell 20 supporting a conditional authorization S-NSSAI-2.

[0086] Figure 12 shows an example of the operation of the AMF 3. In step 1201, the AMF 3 receives a request to establish or activate a PDU session associated with a conditionally granted S-NSSAI (e.g., S-NSSAI-2) from a UE 4 via a first cell (e.g., cell 10) that does not support the conditionally granted S-NSSAI and via a first (R)AN node 1 serving the first cell.

[0087] The AMF 3 knows that the conditionally authorized S-NSSAI (eg, S-NSSAI-2) is available in at least one specific cell, at least one specific frequency band, or at least one specific tracking area. In step 1202, the AMF 3 sends a control message (N2 message) to the first (R)AN node 1. The control message causes the first (R)AN node 1 to provide the UE 4 with a second cell (eg, cell 20) that supports the conditionally authorized S-NSSAI (eg, S-NSSAI-2). In other words, the control message prompts the first (R)AN node 1 to enable the UE 4 to use a radio connection with the second cell (eg, cell 20) that supports the conditionally authorized S-NSSAI (eg, S-NSSAI-2). More specifically, the control message causes the first (R)AN node 1 to move the UE 4 to a second cell (e.g., cell 20) supporting the conditional authorization S-NSSAI (e.g., S-NSSAI-2) or to add the second cell as a secondary cell for the UE 4. The second cell (e.g., cell 20) may be provided by the second (R)AN node 2. In this case, the control message causes the first (R)AN node 1 to request the second (R)AN node to move (or handover) the UE 4 to the second (R)AN node 2 providing the second cell (e.g., cell 20) supporting the conditional authorization S-NSSAI (e.g., S-NSSAI-2) or to add the second cell as a secondary cell for the UE 4.

[0088] The control message may indicate a conditionally authorized S-NSSAI (e.g., S-NSSAI-2). Additionally or alternatively, the control message may indicate at least one identifier (e.g., TAI) of at least one specific tracking area in which the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available. Additionally or alternatively, the control message may indicate at least one identifier (e.g., NR-ARFCN) of at least one specific frequency band in which the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available. Additionally or alternatively, the control message may indicate at least one identifier (e.g., Cell Global Identifier (CGI)) of at least one specific cell in which the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available. The control message may be a PDU SESSION RESOURCE SETUP REQUEST message or a PDU SESSION RESOURCE MODIFY REQUEST message extended to indicate at least one of these identifiers.

[0089] In some implementations, the control message causes the first (R)AN node 1 to handover or redirect the UE 4 to a second cell (e.g., cell 20) that supports the conditional admission S-NSSAI (e.g., S-NSSAI-2). In other implementations, the control message causes the first (R)AN node 1 to add the second cell (e.g., cell 20) as a carrier aggregation or dual connectivity secondary cell for the UE 4. Note that the second cell (e.g., cell 20) may be provided by the second (R)AN node 2. In this case, the control message causes the first (R)AN node 1 to transfer (or handover) the UE 4 to a second (R)AN node 2 that provides a second cell (e.g., cell 20) that supports the conditional admission S-NSSAI (e.g., S-NSSAI-2), or to request the second (R)AN node to add the second cell as a secondary cell for the UE 4.

[0090] 13 shows an example of the operation of the first (R)AN node 1. In step 1301, the first (R)AN node 1 receives a request to establish or activate a PDU session associated with a conditionally granted S-NSSAI (e.g., S-NSSAI-2) from a UE 4 via a first cell (e.g., cell 10) that does not support the conditionally granted S-NSSAI. In step 1302, the first (R)AN node 1 forwards the received request to the AMF 3.

[0091] In step 1303, the first (R)AN node 1 receives a control message (N2 message) from the AMF 3. The control message causes the first (R)AN node 1 to provide the UE 4 with a second cell (eg, cell 20) that supports the conditional authorization S-NSSAI (eg, S-NSSAI-2). In other words, the control message prompts the first (R)AN node 1 to enable the UE 4 to use a radio connection with the second cell (eg, cell 20) that supports the conditional authorization S-NSSAI (eg, S-NSSAI-2). More specifically, the control message causes the first (R)AN node 1 to move the UE 4 to the second cell (eg, cell 20) that supports the conditional authorization S-NSSAI (eg, S-NSSAI-2) or to add the second cell as a secondary cell for the UE 4. Note that the second cell (e.g., cell 20) may be provided by a second (R)AN node 2. In this case, the control message causes the first (R)AN node 1 to transfer (or handover) the UE 4 to the second (R)AN node 2 providing the second cell (e.g., cell 20) that supports the conditional admission S-NSSAI (e.g., S-NSSAI-2) or to request the second (R)AN node to add the second cell as a secondary cell for the UE 4.

[0092] In step 1304, in response to the control message from the AMF 3, the first (R)AN node 1 hands over or redirects the UE 4 to the second cell, or in response to the control message from the AMF 3, the first (R)AN node 1 adds the second cell as a secondary cell for carrier aggregation or dual connectivity for the UE 4.

[0093] In some implementations, the control message from the AMF 3 may indicate a conditionally authorized S-NSSAI (e.g., S-NSSAI-2). In this case, the first (R)AN node 1 may select a cell, (R)AN node, or tracking area that supports the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) as a target cell, target (R)AN node, or target tracking area to handover or redirect the UE 4. Alternatively, the first (R)AN node 1 may add the cell or (R)AN node that supports the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) as a secondary cell or secondary node for carrier aggregation or dual connectivity for the UE 4.

[0094] In some implementations, the control message from the AMF 3 may indicate at least one identifier (e.g., TAI) of at least one particular tracking area for which a conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available. In this case, the first (R)AN node 1 may select a cell or an (R)AN node that serves the tracking area associated with the identifier as a target cell or target (R)AN node to handover or redirect the UE 4. Alternatively, the first (R)AN node 1 may add a cell or an (R)AN node that serves the tracking area associated with the identifier as a secondary cell or secondary node for carrier aggregation or dual connectivity for the UE 4.

[0095] In some implementations, the control message from the AMF 3 may indicate at least one identifier (e.g., NR-ARFCN) of at least one particular frequency band for which the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available. In this case, the first (R)AN node 1 may select a cell operating in or providing a frequency band associated with the identifier as a target cell or target (R)AN node to handover or redirect the UE 4 to. Alternatively, the first (R)AN node 1 may add a cell operating in or providing a frequency band associated with the identifier as a secondary cell or secondary node for carrier aggregation or dual connectivity for the UE 4.

[0096] In some implementations, the control message from the AMF 3 may indicate an identifier (e.g., CGI) of at least one particular cell for which a conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available. In this case, the first (R)AN node 1 may select the cell associated with the identifier or the (R)AN node serving the cell as a target cell or target (R)AN node to handover or redirect the UE 4. Alternatively, the first (R)AN node 1 may add the cell associated with the identifier or the (R)AN node serving the cell as a secondary cell or secondary node for carrier aggregation or dual connectivity for the UE 4.

[0097] To assist the operation of the AMF 3 and the (R)AN node 1 described with reference to Figures 12 and 13, the UE 4 may operate as shown in Figure 14. In step 1401, the UE 4 includes an identifier (e.g., CGI or NR-ARFCN) of a cell or frequency band in which the conditionally granted S-NSSAI (e.g., S-NSSAI-2) is available in a NAS message sent to the AMF 3 to request the establishment or activation of a PDU session associated with the conditionally granted S-NSSAI (e.g., S-NSSAI-2). The NAS message may be a Service Request message. Alternatively, the NAS message may be a NAS message (e.g., UL NAS Transport message) carrying an N1 SM container (PDU Session Establishment Request).

[0098] In some implementations, a cell may broadcast a list of network slice identifiers (S-NSSAIs) available via the cell. In this case, the UE 4 may search for cells for which the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) is available and include the identifier of the found cell in the NAS message of step 1401. Alternatively, the UE 4 may search for cells in a frequency band (e.g., FB-2) associated with the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) in the registration procedure and include the identifier of the found cell in the NAS message of step 1401. Alternatively, the UE 4 may search for cells belonging to a tracking area (e.g., TAI-2) associated with the conditionally authorized S-NSSAI (e.g., S-NSSAI-2) in the registration procedure and include the identifier of the found cell in the NAS message of step 1401.

[0099] The AMF 3 refers to the cell or frequency band identifier (e.g., CGI or NR-ARFCN) received from the UE 4. This allows the AMF 3 to recognize the cell or frequency band to which the UE 4 should be moved or to which it should be added for the UE 4.

[0100] Figure 15 shows an example of handover of UE 4. In step 1501, UE 4 has completed the registration procedure via cell 10 provided by the first (R)AN node 1, is authorized to use S-NSSAI-1, and is conditionally authorized to use S-NSSAI-2. That is, the Allowed NSSAI set by AMF 3 includes S-NSSAI-1, and the Conditional NSSAI set by AMF 3 includes S-NSSAI-2.

[0101] In steps 1502 and 1503, the UE 4 requests the AMF 3 to establish or activate a PDU session associated with the conditionally granted S-NSSAI-2 via the cell 10 of the first (R)AN node 1. The UE 4 may decide to establish or activate the PDU session according to the operations described in the fifth and sixth aspects.

[0102] More specifically, in step 1502, the UE 4 performs an RRC connection establishment procedure in the cell 10 of the first (R)AN node 1. In step 1503, the UE 4 initiates a PDU session establishment procedure or a service request procedure via the cell 10 to establish or activate a PDU session associated with the conditional grant S-NSSAI-2. If the PDU session associated with the conditional grant S-NSSAI-2 is not established, the UE 4 sends a PDU session establishment request message to the AMF 3 via the cell 10. More specifically, the UE 4 sends a NAS message (eg, UL NAS Transport message) carrying an N1 SM container (PDU Session Establishment Request) to the AMF 3. If the PDU session associated with the conditional grant S-NSSAI-2 is already established, the UE 4 sends a service request message to the AMF 3 via the cell 10. The service request message may be an Extended Service Request message. As described with reference to FIG. 14, UE4 may include in the NAS message of step 1503 an identifier (e.g., CGI or NR-ARFCN) of a cell or frequency band in which the conditional grant S-NSSAI-2 is available.

[0103] In step 1504, the AMF 3 decides to provide the UE 4 with a cell (e.g., cell 20) that supports the conditional authorization S-NSSAI-2. The AMF 3 knows the supported S-NSSAIs for each TA supported by the first (R)AN node 1 via the NG Setup procedure or the RAN Configuration Update procedure. Furthermore, the AMF 3 can know the location information of the UE 4, i.e., the identifier (CGI) and TAI of the cell 10 to which the UE 4 is connected, from the N2 message (e.g., INITIAL UE MESSAGE) carrying the NAS message of step 1503. This allows the AMF 3 to know that the conditional authorization S-NSSAI-2 is not available in the cell 10. Furthermore, the AMF 3 knows which (R)AN nodes and TAs support the conditional authorization S-NSSAI-2. Additionally, the AMF 3 may take into account the identifiers (e.g., CGI or NR-ARFCN) of the cells or frequency bands available for which the conditional authorization S-NSSAI-2 received from the UE 4 is available. Based on these findings, the AMF 3 may determine the target (R)AN node, target tracking area, target cell, or target frequency band to which the UE 4 should be transferred (or added for the UE 4).

[0104] In step 1505, the AMF 3 sends an N2 request message to the first (R)AN node 1. The N2 request message indicates the conditional authorization S-NSSAI-2. The N2 request message may further indicate a target (R)AN node, a target tracking area, a target cell, or a target frequency band to which the UE 4 should be moved (or to be added for the UE 4). The N2 request message causes the first (R)AN node 1 to handover the UE 4 to a cell 20 that supports the conditional authorization S-NSSAI-2. The cell 20 may be provided by the second (R)AN node 2. Alternatively, the cell 20 may be provided by the first (R)AN node 1 that provides the cell 10, as already explained.

[0105] In step 1506, the first (R)AN node 1 may cause the RRC_CONNETED UE 4 to perform inter-frequency measurements. If the measurement results by the UE 4 have already been received by the first (R)AN node 1, the measurement in step 1506 may be skipped.

[0106] In step 1507, if a cell 20 supporting the conditional authorization S-NSSAI-2 is available at the location of the UE 4, the first (R)AN node 1 initiates a handover procedure to move the UE 4 to the cell 20. After the handover to the cell 20 is completed, the UE 4 may request the AMF 3 via the cell 20 to establish or activate a PDU session associated with the conditional authorization S-NSSAI-2.

[0107] After the communication via the PDU session associated with the conditionally granted S-NSSAI-2 is terminated, the UE 4 may perform cell reselection from the cell 20 supporting the conditionally granted S-NSSAI-2 back to the cell 10 supporting the authorized S-NSSAI-1. The UE 4 may remain in the cell 10 supporting the authorized S-NSSAI-1 (or any other cell) until a new connection to the conditionally granted S-NSSAI-2 is requested by the application layer.

[0108] FIG. 16 shows an example of a handover failure of UE4. Steps 1601-1606 are similar to steps 1501-1506 in FIG. 15. In step 1607, if a cell 20 supporting conditional authorization S-NSSAI-2 is not available at the location of UE4, the (R)AN node 1 sends an N2 response message to the AMF 3. The N2 response message indicates that the conditional authorization S-NSSAI-2 is not available at the UE location. In step 1608, the AMF 3 rejects the establishment or activation of the PDU session from UE4. The reject message of step 1608 may indicate a reject cause (eg, S-NSSAI not available). The reject message may indicate a back-off timer value.

[0109] Figure 17 shows an example of redirection of UE4. Steps 1701-1705 are similar to steps 1501-1505 of Figure 15. In step 1706, the first (R)AN node 1 sends an RRC Release message to the UE4. The RRC Release message includes an indication of redirection to a cell supporting S-NSSAI-2. The RRC Release message may indicate a tracking area identifier (e.g., TAI), a cell identifier (e.g., CGI), or a frequency band identifier (e.g., ARFCN), or any combination thereof, in which S-NSSAI-2 is available.

[0110] In step 1707, the UE 4 performs cell reselection. In step 1708, the UE 4 reselects the cell 20 supporting the S-NSSAI-2 and performs an RRC connection establishment procedure in the cell 20. The cell 20 may be provided by the second (R)AN node 2. Alternatively, as already explained, the cell 20 may be provided by the first (R)AN node 1 providing the cell 10. In step 1709, the UE 4 requests the AMF 3 via the cell 20 to establish or activate a PDU session associated with the conditionally granted S-NSSAI-2.

[0111] After the communication via the PDU session associated with the conditionally granted S-NSSAI-2 is terminated, the UE 4 may perform cell reselection from the cell 20 supporting the conditionally granted S-NSSAI-2 back to the cell 10 supporting the authorized S-NSSAI-1. The UE 4 may remain in the cell 10 supporting the authorized S-NSSAI-1 (or any other cell) until a new connection to the conditionally granted S-NSSAI-2 is requested by the application layer.

[0112] FIG. 18 shows an example of dual connectivity (DC). Steps 1801-1804 are similar to steps 1501-1504 in FIG. 15. In step 1805, the AMF 3 sends an N2 request message to the first (R)AN node 1, including information elements (e.g., PDU Session ID, PDU Session NAS-PDU, S-NSSAI, and PDU Session Resource Setup / Modify Request Transfer) related to the PDU session associated with the S-NSSAI-2. The N2 request message of step 1805 may indicate an identifier (e.g., NR-ARFCN) of a frequency band in which the conditionally granted S-NSSAI-2 is available. Additionally or alternatively, the N2 request message may indicate an identifier (e.g., CGI) of a cell in which the conditionally granted S-NSSAI-2 is available. The N2 request message may be a PDU SESSION RESOURCE SETUP REQUEST message or a PDU SESSION RESOURCE MODIFY REQUEST message extended to indicate at least one of these identifiers, so that the AMF 3 can specify (or indicate or request) to the first (R)AN node 1 a cell or its frequency band to be used as a secondary cell for the DC.

[0113] In step 1806, the first (R)AN node 1 may cause the RRC_CONNETED UE 4 to perform inter-frequency measurements. If the measurement results by the UE 4 have already been received by the first (R)AN node 1, the measurements in step 1806 may be skipped.

[0114] In step 1807, the first (R)AN node 1 performs an SN addition procedure to add the cell 20 supporting S-NSSAI-2 as a secondary cell (SCG cell). More specifically, the first (R)AN node 1 sends an SN Addition Request message to the second (R)AN node 2. The second (R)AN node 2 sends an SN Addition Request Acknowledge message to the first (R)AN node 1. The SN Addition Request Acknowledge message includes an SN RRC message. Then, the first (R)AN node 1 sends an MN RRC Reconfiguration message to the UE 4. The MN RRC Reconfiguration message includes the SN RRC message received from the second (R)AN node 2 and includes an N1 SM container (e.g., PDU Session Establishment Accept) received from the AMF 3. Thereafter, for the radio bearers of cell 20, the first (R)AN node 1 (or the second (R)AN node 2) establishes or updates a user plane path with the 5GC (User Plane Function (UPF)) via a PDU Session Path Setup or Update procedure, so that the UE 4 can perform DC using cell 10 as the MCG cell and cell 20 as the SCG cell.

[0115] Similar to the other examples already described, cell 20 may be provided by the first (R)AN node 1 that provides cell 10. In this case, the first (R)AN node 1 may perform carrier aggregation instead of dual connectivity.

[0116] Next, the following describes configuration examples of the (R)AN node 1, the (R)AN node 2, the AMF 3, and the UE 4 according to the above-mentioned aspects. FIG. 19 is a block diagram showing a configuration example of the (R)AN node 1 according to the above-mentioned aspects. The (R)AN node 2 may have a similar configuration to that shown in FIG. 19. Referring to FIG. 19, the (R)AN node 1 includes a Radio Frequency (RF) transceiver 1901, a network interface 1903, a processor 1904, and a memory 1905. The RF transceiver 1901 performs analog RF signal processing to communicate with UEs. The RF transceiver 1901 may include multiple transceivers. The RF transceiver 1901 is coupled to an antenna array 1902 and a processor 1904. The RF transceiver 1901 receives modulation symbol data from the processor 1904, generates a transmission RF signal, and provides the transmission RF signal to the antenna array 1902. The RF transceiver 1901 also generates a baseband receive signal based on the receive RF signal received by the antenna array 1902 and supplies the baseband receive signal to the processor 1904. The RF transceiver 1901 may include an analog beamformer circuit for beamforming. The analog beamformer circuit includes, for example, multiple phase shifters and multiple power amplifiers.

[0117] The network interface 1903 is used to communicate with network nodes (e.g., other (R)AN nodes, AMF, and User Plane Function (UPF)). The network interface 1903 may include, for example, a network interface card (NIC) that complies with the IEEE 802.3 series.

[0118] The processor 1904 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. The processor 1904 may include multiple processors. For example, the processor 1904 may include a modem processor (e.g., Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., Central Processing Unit (CPU) or Micro Processing Unit (MPU)) that performs control plane processing.

[0119] For example, digital baseband signal processing by the processor 1904 may include signal processing of a Service Data Adaptation Protocol (SDAP) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a Physical (PHY) layer. Also, control plane processing by the processor 1904 may include processing of Non-Access Stratum (NAS) messages, RRC messages, MAC CEs, and DCIs.

[0120] The processor 1904 may include a digital beamformer module for beamforming, which may include a Multiple Input Multiple Output (MIMO) encoder and a precoder.

[0121] The memory 1905 is configured by a combination of volatile memory and non-volatile memory. The volatile memory is, for example, Static Random Access Memory (SRAM) or Dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is, for example, Mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. The memory 1905 may include storage located remotely from the processor 1904. In this case, the processor 1904 may access the memory 1905 via the network interface 1903 or the I / O interface.

[0122] The memory 1905 may store one or more software modules (computer programs) 1906 including instructions and data for performing processing by the (R)AN node 1 described in the above-mentioned aspects. In some implementations, the processor 1904 may be configured to read the software modules 1906 from the memory 1905 and execute them to perform processing by the (R)AN node 1 described in the above-mentioned aspects.

[0123] In addition, when the (R)AN node 1 is a Central Unit (eg, gNB-CU) in a C-RAN deployment, the (R)AN node 1 may not include an RF transceiver 1901 (and an antenna array 1902).

[0124] FIG. 20 shows an example of the configuration of the AMF 3. Referring to FIG. 20, the AMF 3 includes a network interface 2001, a processor 2002, and a memory 2003. The network interface 2001 is used, for example, to communicate with (R)AN nodes and to communicate with other network functions (NFs) or nodes in the 5GC. The other NFs or nodes in the 5GC include, for example, UDM, AUSF, SMF, and PCF. The network interface 2001 may include, for example, a network interface card (NIC) conforming to the IEEE 802.3 series.

[0125] The processor 2002 may be, for example, a microprocessor, a Micro Processing Unit (MPU), or a Central Processing Unit (CPU). The processor 2002 may include multiple processors.

[0126] The memory 2003 is composed of a volatile memory and a non-volatile memory. The memory 2003 may include a plurality of physically independent memory devices. The volatile memory is, for example, a static random access memory (SRAM) or a dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is, for example, a mask read only memory (MROM), an electrically erasable programmable ROM (EEPROM), a flash memory, or a hard disk drive, or any combination thereof. The memory 2003 may include a storage located away from the processor 2002. In this case, the processor 2002 may access the memory 2003 via the network interface 2001 or an I / O interface.

[0127] The memory 2003 may store at least one software module (computer program) 2004 including instructions and data for performing processing by the AMF 3 described in the above-mentioned aspects. In some implementations, the processor 2002 may be configured to read the software module 2004 from the memory 2003 and execute it to perform processing by the AMF 3 described in the above-mentioned aspects.

[0128] FIG. 21 is a block diagram showing a configuration example of the UE4. The Radio Frequency (RF) transceiver 2101 performs analog RF signal processing to communicate with (R)AN nodes. The RF transceiver 2101 may include multiple transceivers. The analog RF signal processing performed by the RF transceiver 2101 includes frequency up-conversion, frequency down-conversion, and amplification. The RF transceiver 2101 is coupled to the antenna array 2102 and the baseband processor 2103. The RF transceiver 2101 receives modulation symbol data (or OFDM symbol data) from the baseband processor 2103, generates a transmission RF signal, and provides the transmission RF signal to the antenna array 2102. The RF transceiver 2101 also generates a baseband reception signal based on the reception RF signal received by the antenna array 2102, and provides the baseband reception signal to the baseband processor 2103. The RF transceiver 2101 may include an analog beamformer circuit for beamforming. The analog beamformer circuitry includes, for example, multiple phase shifters and multiple power amplifiers.

[0129] The baseband processor 2103 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Digital baseband signal processing includes (a) data compression / decompression, (b) data segmentation / concatenation, (c) generation / decomposition of transmission format (transmission frame), (d) transmission line coding / decoding, (e) modulation (symbol mapping) / demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) by Inverse Fast Fourier Transform (IFFT). Meanwhile, control plane processing includes communication management of layer 1 (e.g., transmission power control), layer 2 (e.g., radio resource management, and hybrid automatic repeat request (HARQ) processing), and layer 3 (e.g., signaling related to attachment, mobility, and call management).

[0130] For example, the digital baseband signal processing by the baseband processor 2103 may include signal processing of a Service Data Adaptation Protocol (SDAP) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a Physical (PHY) layer. Also, the control plane processing by the baseband processor 2103 may include processing of a Non-Access Stratum (NAS) protocol, a Radio Resource Control (RRC) protocol, and MAC Control Elements (CEs).

[0131] The baseband processor 2103 may perform Multiple Input Multiple Output (MIMO) encoding and precoding for beamforming.

[0132] The baseband processor 2103 may include a modem processor (e.g., Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., Central Processing Unit (CPU) or Micro Processing Unit (MPU)) that performs control plane processing. In this case, the protocol stack processor that performs control plane processing may be shared with the application processor 2104 described later.

[0133] The application processor 2104 is also called a CPU, an MPU, a microprocessor, or a processor core. The application processor 2104 may include multiple processors (multiple processor cores). The application processor 2104 executes a system software program (operating system (OS)) and various application programs (e.g., a calling application, a web browser, a mailer, a camera operation application, and a music playback application) read from the memory 2106 or other memories, thereby realizing various functions of UE4.

[0134] In some implementations, the baseband processor 2103 and the application processor 2104 may be integrated on a single chip, as shown by the dashed line (2105) in Figure 21. In other words, the baseband processor 2103 and the application processor 2104 may be implemented as a single System on Chip (SoC) device 2105. An SoC device may also be referred to as a system Large Scale Integration (LSI) or a chipset.

[0135] The memory 2106 is a volatile memory or a non-volatile memory, or a combination thereof. The memory 2106 may include a plurality of physically independent memory devices. The volatile memory is, for example, a Static Random Access Memory (SRAM) or a Dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is a Mask Read Only Memory (MROM), an Electrically Erasable Programmable ROM (EEPROM), a flash memory, or a hard disk drive, or any combination thereof. For example, the memory 2106 may include an external memory device accessible from the baseband processor 2103, the application processor 2104, and the SoC 2105. The memory 2106 may include an internal memory device integrated in the baseband processor 2103, the application processor 2104, or the SoC 2105. Furthermore, the memory 2106 may include a memory in a Universal Integrated Circuit Card (UICC).

[0136] The memory 2106 may store one or more software modules (computer programs) 2107 including instructions and data for performing processing by the UE 4 described in the above-mentioned aspects. In some implementations, the baseband processor 2103 or the application processor 2104 may be configured to read the software module 2107 from the memory 2106 and execute it to perform processing by the UE 4 described in the above-mentioned aspects using the drawings.

[0137] In addition, the control plane processing and operations performed by UE4 described in the above-mentioned aspects can be realized by elements other than the RF transceiver 2101 and the antenna array 2102, i.e., at least one of the baseband processor 2103 and the application processor 2104, and the memory 2106 storing the software module 2107.

[0138] As described with reference to FIG. 19, FIG. 20, and FIG. 21, each of the processors included in the (R)AN node 1, the (R)AN node 2, the AMF 3, and the UE 4 according to the above-mentioned aspects executes one or more programs including instructions for causing a computer to execute the algorithm described with reference to the drawings. The programs can be stored and provided to a computer using various types of non-transitory computer readable media. The non-transitory computer readable media includes various types of tangible storage media. Examples of the non-transitory computer readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), Compact Disc Read Only Memory (CD-ROM), CD-R, CD-R / W, and semiconductor memory (e.g., mask ROM, programmable ROM (PROM), erasable PROM (EPROM), flash ROM, random access memory (RAM)). The program may be provided to the computer by various types of transitory computer readable media. Examples of the transitory computer readable medium include an electric signal, an optical signal, and an electromagnetic wave. The transitory computer readable medium may provide the program to the computer via a wired communication path such as an electric wire and an optical fiber, or via a wireless communication path.

[0139] <Other aspects> The above-mentioned aspects may be implemented independently of each other, or all or part of the aspects may be appropriately combined and implemented.

[0140] Furthermore, the above-mentioned embodiments are merely examples of application of the technical idea obtained by the inventor of the present invention. In other words, the technical idea is not limited to the above-mentioned embodiments, and various modifications are possible.

[0141] For example, some or all of the above embodiments may be described as, but are not limited to, the following supplementary notes.

[0142] (Appendix 1) An Access and Mobility management Function (AMF) device, At least one memory; at least one processor coupled to the at least one memory; Equipped with The at least one processor: receiving a registration request message from a User Equipment (UE) via a first Access Network (AN) node; in response to receiving the registration request message, sending to the UE via the first RAN node a registration accept message indicating a registration area of ​​the UE and a first list of at least one conditionally allowed network slice identifier; It is configured as follows: The registration area is a list of at least one tracking area; Each conditionally authorized network slice identifier is not available in the entire registration area, but is available in at least one specific cell or at least one specific tracking area included in the registration area. AMF device. (Appendix 2) Each of the at least one conditionally authorized network slice identifier indicates a network slice available in at least one particular cell operating in a particular frequency band. 2. The AMF device according to claim 1. (Appendix 3) The registration approval message indicates the particular frequency band in which the network slice indicated by each of the at least one conditionally authorized network slice identifier operates. 2. An AMF device as described in Appendix 2. (Appendix 4) Each of the at least one conditionally authorized network slice identifier is available in the at least one particular tracking area; and The registration acceptance message indicates the at least one particular tracking area in which each conditionally authorized network slice identifier is available. 2. The AMF device according to claim 1. (Appendix 5) An AMF device described in any one of Supplementary Notes 1 to 4, wherein the registration area includes the at least one specific tracking area and at least one other tracking area in which the at least one conditionally authorized network slice identifier is not available. (Appendix 6) The at least one processor is further configured to include in the registration accept message a second list of at least one authorized network slice identifier available to the UE throughout the registration area. 6. The AMF device according to any one of claims 1 to 5. (Appendix 7) The at least one processor is configured to include the first list in the registration accept message in response to receiving the registration request message including a specific indication that the UE supports conditional authorization of network slice identifiers. 7. The AMF device according to any one of claims 1 to 6. (Appendix 8) A User Equipment (UE), At least one memory; at least one processor coupled to the at least one memory; Equipped with The at least one processor: Sending a registration request message to an Access and Mobility management Function (AMF) via a first Access Network (AN) node; receiving a registration accept message from the AMF via the first RAN node, the registration accept message indicating a registration area of ​​the UE and a first list of at least one conditionally allowed network slice identifier; It is configured as follows: The registration area is a list of at least one tracking area; Each conditionally authorized network slice identifier is not available in the entire registration area, but is available in at least one specific cell or at least one specific tracking area included in the registration area. U.E. (Appendix 9) Each of the at least one conditionally authorized network slice identifier indicates a network slice available in at least one particular cell operating in a particular frequency band. UE as described in Appendix 8. (Appendix 10) The registration approval message indicates the particular frequency band in which the network slice indicated by each of the at least one conditionally authorized network slice identifier operates. UE as described in Appendix 9. (Appendix 11) Each of the at least one conditionally authorized network slice identifier is available in the at least one particular tracking area; The registration approval message indicates the at least one particular tracking area in which each conditionally authorized network slice identifier is available. UE as described in Appendix 8. (Appendix 12) The registration area includes the at least one specific tracking area and at least one other tracking area in which the at least one conditionally authorized network slice identifier is not available. The UE according to any one of appendix 8 to 11. (Appendix 13) The at least one processor is further configured to receive via the registration accept message a second list of at least one authorized network slice identifier available to the UE throughout the registration area. The UE according to any one of appendix 8 to 12. (Appendix 14) The at least one processor is configured to include in the registration request message a specific indication that the UE supports conditional authorization of a network slice identifier. The UE according to any one of appendix 8 to 13. (Appendix 15) The at least one processor is configured to request a core network to establish or activate a protocol data unit (PDU) session associated with a conditionally authorized network slice identifier included in the first list only when the UE detects any of the at least one particular cell or any of the at least one particular tracking area. The UE according to any one of appendix 8 to 14. (Appendix 16) The at least one processor is configured to include a cell identifier of any of the at least one particular cell or an identifier of a frequency band in which the at least one particular cell operates in a Non-Access Stratum (NAS) message transmitted to the core network to request establishment or activation of the PDU session. 15. The UE as described in Appendix 15. (Appendix 17) The at least one processor is configured to, in response to detecting any of the at least one particular cell, a frequency band in which the at least one particular cell operates, or the at least one particular tracking area, notify an application layer that the at least one conditionally authorized network slice identifier is available. The UE according to any one of appendixes 8 to 16. (Appendix 18) A method performed by an Access and Mobility management Function (AMF) device, comprising: receiving a registration request message from a User Equipment (UE) via a first Access Network (AN) node; and in response to receiving the registration request message, sending a registration accept message to the UE via the first RAN node, the registration accept message indicating a registration area of ​​the UE and a first list of at least one conditionally allowed network slice identifier; Equipped with The registration area is a list of at least one tracking area; Each conditionally authorized network slice identifier is not available in the entire registration area, but is available in at least one specific cell or at least one specific tracking area included in the registration area. method. (Appendix 19) A method performed by a User Equipment (UE), comprising: Sending a registration request message to an Access and Mobility management Function (AMF) via a first Access Network (AN) node; and receiving a registration accept message from the AMF via the first RAN node, indicating a registration area of ​​the UE and a first list of at least one conditionally allowed network slice identifier; Equipped with The registration area is a list of at least one tracking area; Each conditionally authorized network slice identifier is not available in the entire registration area, but is available in at least one specific cell or at least one specific tracking area included in the registration area. method. (Appendix 20) A program for causing a computer to perform a method for an Access and Mobility management Function (AMF) device, comprising: The method comprises: receiving a registration request message from a User Equipment (UE) via a first Access Network (AN) node; and in response to receiving the registration request message, sending a registration accept message to the UE via the first RAN node, the registration accept message indicating a registration area of ​​the UE and a first list of at least one conditionally allowed network slice identifier; Equipped with The registration area is a list of at least one tracking area; Each conditionally authorized network slice identifier is not available in the entire registration area, but is available in at least one specific cell or at least one specific tracking area included in the registration area. program. (Appendix 21) A program for causing a computer to perform a method for User Equipment (UE), The method comprises: Sending a registration request message to an Access and Mobility management Function (AMF) via a first Access Network (AN) node; and receiving a registration accept message from the AMF via the first RAN node, indicating a registration area of ​​the UE and a first list of at least one conditionally allowed network slice identifier; Equipped with The registration area is a list of at least one tracking area; Each conditionally authorized network slice identifier is not available in the entire registration area, but is available in at least one specific cell or at least one specific tracking area included in the registration area. program.

[0143] This application claims priority based on Japanese Patent Application No. 2020-067096, filed on April 2, 2020, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0144] 1 (R)AN node 2 (R)AN nodes 3. AMF 4. UE 1905 Memory 1906 Modules 2003 Memory 2004 Modules 2103 Baseband Processor 2104 Application Processor 2107 Modules

Claims

1. A method for receiving a registration request message from a User Equipment (UE), the registration request message including first information indicating that the UE supports a network slice available in a part of a Tracking Area (TA) in a registration area of ​​the UE, and second information indicating a Requested Network Slice Selection Assistance Information (NSSAI); A transmission means for transmitting a registration acknowledgement message to the UE, the registration acknowledgement message including third information indicating at least one Single Network Slice Selection Assistance Information (S-NSSAI) included in an NSSAI related to a network slice available in a TA of a portion of TAs in a registration area of ​​the UE, and fourth information indicating a list of Tracking Area Identity (TAI) related to at least one S-NSSAI included in the NSSAI; An Access and Mobility management Function (AMF) comprising:

2. The transmission means transmits, to the UE, the registration approval message including the third information and the fourth information based on at least the first information and the second information.

2. The AMF of claim 1.

3. The Requested NSSAI includes the at least one S-NSSAI included in the NSSAI.

3. The AMF according to claim 1 or 2.

4. A registration request message including first information indicating that a User Equipment (UE) supports a network slice available in a part of a Tracking Area (TA) in a registration area of ​​the UE, and second information indicating a Requested Network Slice Selection Assistance Information (NSSAI), is sent to an Access and Mobility management Function (AMF); A means for receiving a registration approval message from the AMF, the registration approval message including third information indicating at least one Single Network Slice Selection Assistance Information (S-NSSAI) included in an NSSAI regarding network slices available in a portion of TAs in a registration area of ​​the UE, and fourth information indicating a list of Tracking Area Identities (TAIs) for the at least one S-NSSAI included in the NSSAI; A UE comprising:

5. The UE of claim 4, further comprising: means for sending a Protocol Data Unit (PDU) session establishment request message for the at least one S-NSSAI to the AMF when the UE is in a first TA that supports the at least one S-NSSAI.

6. The Requested NSSAI includes the at least one S-NSSAI included in the NSSAI.

6. The UE according to claim 4 or 5.

7. Receive a registration request message from a User Equipment (UE), the registration request message including first information indicating that the UE supports a network slice available in a tracking area (TA) in a registration area of ​​the UE, and second information indicating a Requested Network Slice Selection Assistance Information (NSSAI); and transmitting to the UE a registration acknowledgement message including third information indicating at least one Single Network Slice Selection Assistance Information (S-NSSAI) included in an NSSAI related to a network slice available in a portion of TAs within a registration area of ​​the UE, and fourth information indicating a list of Tracking Area Identities (TAIs) related to the at least one S-NSSAI included in the NSSAI; A method for Access and Mobility management Function (AMF).

8. Send a registration request message to an Access and Mobility management Function (AMF), the registration request message including first information indicating that the UE supports a network slice available in a part of a tracking area (TA) in a registration area of ​​the UE, and second information indicating a Requested Network Slice Selection Assistance Information (NSSAI); Receive from the AMF a registration approval message including third information indicating at least one Single Network Slice Selection Assistance Information (S-NSSAI) included in an NSSAI regarding a network slice available in a TA of a portion of TAs within a registration area of ​​the UE, and fourth information indicating a list of Tracking Area Identity (TAI) regarding at least one S-NSSAI included in the NSSAI; A method for a UE.

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