Radio access network node device and method thereof

Abstract

To allow an AMF to determine a network slices allowed to UE while taking into account the network slices supported by a secondary node of dual connectivity.SOLUTION: A RAN node device receives a message including one or more network slice identifiers from UE. The RAN node device receives slice support information indicating one or more network slice identifiers supported by other RAN nodes that can be used as a secondary node in dual connectivity in which the RAN node device operates as a master node. Further, the RAN node device sends at least one network slice identifier included in the received slice support information to the AMF of the core network.SELECTED DRAWING: Figure 2

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 uses Network Function Virtualization (NFV) technology and software-defined networking (SDN) technology to enable the creation of multiple virtualized logical networks on a physical network. Each virtualized logical network is called a network slice. A network slice provides specific network capabilities and network characteristics. A network slice instance (NSI) is defined from a network function (NF) instance in a core network (CN) and resources (e.g., computer processing resources, storage, and networking resources) to form one network slice. Additionally, the NSI may be defined as a set of NF instances and resources in the CN and an access network (AN) (one or both of a Next Generation Radio Access Network (NG-RAN) and a Non-3GPP (registered trademark) InterWorking Function (N3IWF)).

[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 values ​​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 assists the network in 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, one or more S-NSSAIs 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 one or more S-NSSAIs, each applicable to one or more PLMNs. 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, one or more network slices, and one or more NSIs for the UE.

[0008] The Allowed NSSAI is provided to the UE by the Serving PLMN and indicates one or more S-NSSAIs 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 one or more S-NSSAIs rejected by the current PLMN. The Rejected NSSAI is sometimes called rejected S-NSSAIs. The S-NSSAI is rejected by the entire current PLMN or rejected in the current registration area. If the AMF rejects one or more S-NSSAIs 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 one or more S-NSSAIs 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] Nokia, Nokia Shanghai Bell, ZTE, Sanechips, Telecom Italia, Sprint, NEC, KDDI; Deutsche Telekom, InterDigital, Orange, Vodafone, Verizon UK Ltd, UIC, ETRI, Broadcom, Lenovo, Cisco, Telefonica S.A., Huawei, China Mobile, CATT, " New WID Study on Enhancement of Network Slicing Phase 2", S2-1908583, 3GPP TSG-SA WG2 Meeting #134, Sapporo, Japan, 24-28 June 2019 [Non-Patent Document 4] CMCC, Verizon, " Study on enhancement of RAN Slicing", RP-193254, 3GPP TSG-RAN meeting #86, Sitges, Barcelona, 9-12 December 2019 [Non-Patent Document 5] Samsung, AT&T, Sprint, InterDigital, China Mobile, SK Telecom, Convida Wireless, ZTE, Apple, KDDI, "Key Issue on 5GC assisted cell selection to access network slice", S2-2001467, 3GPP TSG-SA WG2 Meeting #136 Ad-hoc, Incheon, Korea, 13-17 January 2020 Summary of the Invention [Problem to be solved by the invention]

[0013] The inventors have investigated network slicing and found various issues. One of the issues is a case in which a master node (MN) of dual connectivity (DC) does not support a network slice that a UE intends to use, but a secondary node (SN) supports the network slice.

[0014] According to the current 3GPP specifications, an NG-RAN node capable of acting as a MN in a DC (hereafter referred to as a potential or candidate MN) informs the Access and Mobility management Function (AMF) in a 5G Core Network (5GC) of the network slices supported by the potential MN. More specifically, the potential MN provides the AMF with a Supported TA List information element (IE) and a TAI Slice Support List IE in a setup procedure of application level configuration data required for interworking with the AMF over a control plane interface (i.e., N2 (or NG-C) interface). The Supported TA List IE indicates the Tracking Areas (TAs) supported in the potential MN. 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)). Single Network Slice Selection Assistance Information (S-NSSAI) is an identifier for a network slice.

[0015] Furthermore, according to current 3GPP specifications, the candidate MN exchanges information on supported network slices during a control plane (CP) interface (i.e., Xn-C interface) setup procedure with an NG-RAN node (hereafter referred to as a potential (candidate) SN) capable of acting as an SN for a DC. More specifically, the candidate MN receives a TAI Support List IE and a TAI Slice Support List IE from the candidate SN. The TAI Support List IE indicates the TAs supported in the candidate SN. The TAI Slice Support List IE is included in the TAI Support List IE and indicates the supported S-NSSAIs per TA (or TAI).

[0016] However, if the candidate SN is only responsible for the role of a DC SN, the candidate SN does not have a RAN-CN CP interface (i.e., N2 (or NG-C) interface) with the AMF and therefore does not share information about the network slices it supports with the AMF. If a UE selects the candidate MN for a 5GC registration procedure 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, the AMF knows that the candidate MN does not support S-NSSAI #2 and therefore does 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 a DC SN, the UE may not be able to use the service via S-NSSAI #2.

[0017] One of the objectives of the embodiments disclosed herein is to provide an apparatus, a method, and a program that contribute to enabling the AMF to determine a network slice permitted to a UE while considering a network slice supported by a secondary node of dual connectivity. It should be noted that this objective is only one of the objectives of 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]

[0018] In a first aspect, a RAN node equipment comprises at least one memory and at least one processor coupled to the at least one memory, the at least one processor configured to send slice support information to an AMF of a core network, the slice support information indicating network slices supported by other RAN nodes that may be used as secondary nodes in dual connectivity in which the RAN node equipment operates as a master node.

[0019] In a second 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 configured to receive, from a first Radio Access Network (RAN) node, slice support information indicating network slices supported by a second RAN node that may be used as a secondary node in dual connectivity in which the first RAN node operates as a master node.

[0020] In a third aspect, a method performed by a RAN node apparatus includes sending slice support information to an AMF of a core network, the slice support information indicating network slices supported by other RAN nodes that may be used as secondary nodes in dual connectivity in which the RAN node apparatus operates as a master node.

[0021] In a fourth aspect, a method performed by an AMF device includes receiving, from a first Radio Access Network (RAN) node, slice support information indicating network slices supported by a second RAN node that may be used as a secondary node in dual connectivity in which the first RAN node operates as a master node.

[0022] In a fifth aspect, a program includes a set of instructions (software code) for causing a computer to carry out the method according to the third or fourth aspect above when the program is loaded into the computer. Effect of the Invention

[0023] According to the above-mentioned aspects, an apparatus, a method, and a program can be provided that contribute to enabling an AMF to determine a network slice allowed for a UE while taking into account a network slice supported by a secondary node of dual connectivity. [Brief description of the drawings]

[0024] [Figure 1] 1 is a diagram illustrating an example of the configuration of a wireless communication network according to an embodiment. [Diagram 2] FIG. 11 is a sequence diagram showing an example of signaling according to an embodiment. [Diagram 3] 10 is a flowchart illustrating an example of an operation of AMF according to an embodiment. [Figure 4] FIG. 11 is a sequence diagram showing an example of signaling according to an embodiment. [Diagram 5] A figure showing an example of the format of a RAN CONFIGURATION UPDATE message. [Figure 6] FIG. 11 is a sequence diagram showing an example of signaling according to an embodiment. [Figure 7] A figure showing an example of the format of an INITIAL UE MESSAGE message. [Figure 8] A figure showing an example of the format of an INITIAL UE MESSAGE message. [Figure 9] FIG. 2 is a block diagram showing a configuration example of a RAN node according to the embodiment. [Figure 10] FIG. 2 is a block diagram showing an example of the configuration of an AMF according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] In the following, 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.

[0026] The multiple embodiments described below can be implemented independently or in appropriate combination. These multiple embodiments have different novel features. Therefore, these multiple embodiments contribute to solving different objects or problems and provide different effects.

[0027] The following embodiments are described with a focus on the 3GPP fifth generation mobile communication system (5G system (5GS)). Furthermore, these embodiments are described with a focus on DC in a RAN node (NG-RAN) and a radio terminal (UE) connected to the 5GC. Such DC is called Multi-Radio Dual Connectivity (MR-DC). However, these embodiments may be applied to other radio communication systems that support network slicing similar to 5GS and similar dual connectivity.

[0028] <First embodiment> Fig. 1 illustrates an example of the configuration of a wireless communication network (i.e., 5GS) according to some embodiments including the present embodiment. In the example of Fig. 1, the wireless communication network includes Radio Access Network (RAN) nodes 1 and 2 and an AMF 3. Each element (network function) illustrated in Fig. 1 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.

[0029] The RAN nodes 1 and 2 are deployed in a RAN (i.e., NG-RAN). The RAN nodes 1 and 2 may be gNBs. The RAN nodes 1 and 2 may be Central Units (e.g., gNB-CUs) in a cloud RAN (C-RAN) deployment.

[0030] In the example of Figure 1, the first RAN node 1 and the second RAN node 2 can operate as a master node (MN) and a secondary node (SN) of a dual connectivity (DC), respectively. In the following, the first RAN node 1 may be referred to as a potential (candidate) MN, and the second RAN node 2 may be referred to as a candidate SN.

[0031] The first RAN node (candidate MN) 1 and the second RAN node (candidate SN) 2 can exchange signaling messages over a control plane (CP) interface 101 (i.e., Xn-C interface). Furthermore, the first RAN node (candidate MN) 1 terminates a RAN-CN CP interface 102 (i.e., N2 (or NG-C) interface) and interworks with the AMF 3 over the interface 102. In contrast, the second RAN node (candidate SN) 2 is only responsible for the role of an SN of the DC in a non-standalone deployment and may not have a RAN-CN CP interface (i.e., N2 (or NG-C) interface) with any AMF.

[0032] The AMF3 is one of the network functions in the 5GC control plane. The AMF3 provides the termination of the RAN-CN CP interface 102 (i.e., the N2 (or NG-C) interface). The AMF3 terminates a single signaling connection (i.e., the N1 NAS signalling connection) with the UE 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 the service-based interface (i.e., the Namf interface). Furthermore, the AMF3 consumes NF services provided by other NFs (e.g., the UDM, the Network Slice Selection Function (NSSF), and the Policy Control Function (PCF)).

[0033] 2 shows an example of signaling between a first RAN node (candidate MN) 1 and an AMF 3 according to the present embodiment. In step 201, the first RAN node (candidate MN) 1 sends slice support information to the AMF 3 indicating network slices supported by a second RAN node (candidate SN) 2. In other words, the first RAN node 1 sends slice support information to the AMF 3 indicating network slices supported by the second RAN node 2 that may be used as an SN in a DC in which the first RAN node 1 operates as an MN. The slice support information may, for example, include a list of one or more network slices.

[0034] The slice support information may indicate slice identifiers (i.e., S-NSSAIs) of one or more network slices supported by the second RAN node (candidate SN) 2. More specifically, the slice support information may be associated with Tracking Areas (TAs) supported in the second RAN node (candidate SN) 2, and may include a list of supported S-NSSAIs per TA supported by the second RAN node (potential SN) 2. Note that the one or more network slices supported by the second RAN node (candidate SN) 2 may be pre-configured in the second RAN node (candidate SN) 2, or may be configured (or appropriately changed) by an Operation and Maintenance (O&M) device.

[0035] In some implementations, the first RAN node 1 may send slice support information indicating network slices supported by the second RAN node 2 to the AMF 3 using a non-UE associated signaling message. More specifically, the first RAN node 1 may send the slice support information to the AMF 3 via a NG SETUP REQUEST message or a RAN CONFIGURATION UPDATE message. The NG SETUP REQUEST message is sent in an NG Setup procedure. The NG Setup procedure is performed to set up application level configuration data required for the first RAN node 1 and the AMF 3 to interwork over the RAN-CN CP interface 102 (i.e., N2 (or NG-C) interface). The RAN CONFIGURATION UPDATE message is sent in a RAN Configuration Update procedure. The RAN Configuration Update procedure is performed to update application level configuration data required for the first RAN node 1 and the AMF 3 to interwork over the RAN-CN CP interface 102 (i.e., N2 (or NG-C) interface).

[0036] Alternatively, the first RAN node 1 may send the slice support information (indicating the network slices supported by the second RAN node 2) to the AMF 3 via a UE associated signaling message. More specifically, in response to receiving a Non-Access Stratum (NAS) message and an Access Stratum (AS) message including a Requested NSSAI from the UE, the first RAN node 1 may send the slice support information (indicating the network slices supported by the second RAN node 2) to the AMF 3 via an N2 (NG-C) signaling message for forwarding the NAS message to the AMF 3. The AS message may be an RRC Setup Complete message. The N2 signaling message may be an INITIAL UE MESSAGE message.

[0037] In other words, in response to receiving an RRC setup complete message containing a NAS message (registration request message) from the UE, the first RAN node 1 may send the slice support information (indicating the network slice supported by the second RAN node 2) to the AMF 3 via an INITIAL UE MESSAGE message for forwarding the NAS message (registration request message) to the AMF 3. The NAS message (registration request message) is sent in a registration procedure. The 5GS registration procedure is used, for example, for initial registration, periodic registration, and mobility registration. Initial registration is used by a UE to connect to the network after power-on. Periodic registration is used by a UE in a Connection Management (CM)-IDLE state to inform the network that the UE is still present. Mobility registration is used by the UE when the UE moves out of the registration area or when the UE capabilities or other parameters negotiated in the registration procedure need to be updated.

[0038] In some implementations, the first RAN node 1 may receive an Xn-C message from the second RAN node 2 indicating network slices supported by the second RAN node 2. The first RAN node 1 may receive information of network slices supported by the second RAN node 2 via an XN SETUP REQUEST message or an XN SETUP RESPONSE message in a setup procedure of the Xn-C interface. More specifically, the first RAN node 1 may receive a TAI Support List IE and a TAI Slice Support List IE from the second RAN node 2. The TAI Support List IE indicates TAs supported in the second RAN node 2. The TAI Slice Support List IE is included in the TAI Support List IE and indicates supported S-NSSAIs per TA (or TAI).

[0039] According to the procedure of Fig. 2, the candidate MN1 can inform the AMF3 of the network slices supported by the candidate SN2 that can be used for dual connectivity. The AMF3 can know the network slices supported by the candidate SN2 that the candidate MN1 can use for dual connectivity. Thus, for example, as shown in Fig. 3, the AMF3 can determine the network slices allowed for the UE (e.g., Allowed NSSAI, or list of allowed S-NSSAIs) while considering the network slices supported by the candidate SN2 for dual connectivity.

[0040] 3 shows an example of the operation of the AMF 3. In step 301, the AMF 3 receives a NAS message (registration request message) from the UE via the first RAN node (candidate MN) 1. In step 302, the AMF 3 determines one or more network slices to be allowed for the UE, taking into account network slices supported by the second RAN node (candidate SN) 2. Specifically, if an S-NSSAI included in the Requested NSSAI received from the UE via the NAS message (registration request message) is identical to or corresponds to one of the S-NSSAIs of the network slices supported by the second RAN node (candidate SN) 2, the AMF 3 may generate an Allowed NSSAI including the S-NSSAI and send it to the UE.

[0041] According to the procedure of Fig. 3, the AMF 3 can authorize the UE to use S-NSSAI(s) that are not supported in the cell (candidate Master Cell Group (MCG) cell) of the first RAN node (candidate MN) 1 where the UE performed the registration procedure, but are supported only in the cell (candidate Secondary Cell Group (SCG) cell) of the second RAN node (candidate SN) 2. This can enable the UE to use services via the intended network slice when the second RAN node (candidate SN) 2 is only responsible for the role of a DC SN in a non-standalone deployment and does not have a RAN-CN CP interface (i.e., N2 (or NG-C) interface) with any AMF.

[0042] As can be understood from the above description, the operations of the RAN node 1 and the AMF 3 shown in Figures 2 and 3 are particularly effective when the second RAN node (candidate SN) 2 is responsible for only the role of an SN of a DC in a non-standalone deployment and does not have a RAN-CN CP interface (i.e., an N2 (or NG-C) interface) with any AMF. That is, these operations can enable a UE to use a network slice supported only by an SN in a non-standalone deployment.

[0043] <Second embodiment> A configuration example of a wireless communication network according to this embodiment is similar to the example shown in Fig. 1. This embodiment provides a specific procedure that a first RAN node (candidate MN) 1 can use to inform an AMF 3 of one or more network slices supported by a second RAN node (candidate SN) 2.

[0044] Figure 4 shows an example of signaling according to this embodiment. In step 401, the first RAN node 1 receives slice support information indicating a network slice supported by the second RAN node 2 from the second RAN node 2 via an XN SETUP REQUEST message or an XN SETUP RESPONSE message. More specifically, if the first RAN node 1 initiates an Xn Setup procedure, the first RAN node may receive the slice support information via an XN SETUP RESPONSE message. Alternatively, if the second RAN node 2 initiates an Xn Setup procedure, the first RAN node may receive the slice support information via an XN SETUP REQUEST message.

[0045] As already explained, the slice support information may be a list of S-NSSAIs supported by the second RAN node 2. More specifically, the first RAN node 1 may receive a TAI Support List IE and a TAI Slice Support List IE from the second RAN node 2. The TAI Support List IE indicates TAs supported in the second RAN node 2. The TAI Slice Support List IE is included in the TAI Support List IE and indicates supported S-NSSAIs per TA (or TAI).

[0046] In step 402, the first RAN node 1 sends slice support information indicating the network slices supported by the second RAN node (candidate SN) 2 to the AMF 3 via an NG SETUP REQUEST message or a RAN CONFIGURATION UPDATE message. More specifically, if the NG Setup procedure has not yet been performed between the first RAN node 1 and the AMF 3, the first RAN node 1 may send the slice support information via an NG SETUP REQUEST message. Alternatively, if the NG Setup procedure has been successfully completed between the first RAN node 1 and the AMF 3, the first RAN node 1 may send the slice support information via a RAN CONFIGURATION UPDATE message. In response to receiving an Xn-C message (step 401) including slice support information indicating the network slices supported by the second RAN node 2, the first RAN node 1 may send an N2(NG-C) message including slice support information indicating the network slices supported by the second RAN node (candidate SN) 2 to the AMF 3 (step 402).

[0047] As already explained, the slice support information may indicate slice identifiers (i.e., S-NSSAIs) of one or more network slices supported by the second RAN node (potential SN) 2. The slice support information may be associated with Tracking Areas (TAs) supported in the second RAN node (potential SN) 2 and may include a list of supported S-NSSAIs per TA supported by the second RAN node (potential SN) 2.

[0048] 5 shows a specific example of the format of the RAN CONFIGURATION UPDATE message sent in step 402. In the example of FIG. 5, the Supported TA List includes the Supported TA Item of Secondary RAT. The Supported TA Item of Secondary RAT includes the TAI Slice Support List. The TAI Slice Support List includes a list of S-NSSAIs supported by the Secondary RAT (i.e., the second RAN node (candidate SN) 2) for the TA. The NG SETUP REQUEST message may also include the Supported TA Item of Secondary RAT similar to that shown in FIG. 5.

[0049] According to the procedure of FIG. 4, the first RAN node 1 may send slice support information indicating network slices supported by the second RAN node 2 to the AMF 3 via a non-UE associated signaling message. In one example, in response to receiving a NAS message (registration request message) from the UE via the first RAN node (candidate MN) 1, the AMF 3 may determine network slices (e.g., Allowed NSSAI, or list of allowed S-NSSAIs) allowed for the UE while considering network slices supported by the candidate SN 2 for dual connectivity. Specifically, if the S-NSSAI included in the Requested NSSAI received from the UE via the NAS message (registration request message) is identical to or corresponds to one of the S-NSSAIs of the network slices supported by the second RAN node (candidate SN) 2, the AMF 3 may include the S-NSSAI in the Allowed NSSAI of the UE.

[0050] <Third embodiment> A configuration example of the wireless communication network according to this embodiment is similar to the example shown in Fig. 1. This embodiment provides another specific procedure that the first RAN node (candidate MN) 1 can use to inform the AMF 3 of one or more network slices supported by the second RAN node (candidate SN) 2.

[0051] Figure 6 shows an example of signaling according to this embodiment. Step 601 is similar to step 401 in Figure 4. Specifically, the first RAN node 1 receives slice support information from the second RAN node 2 via an XN SETUP REQUEST message or an XN SETUP RESPONSE message, the slice support information indicating network slices supported by the second RAN node 2. The slice support information may, for example, include a list of one or more network slices.

[0052] Steps 602 and 603 relate to a registration procedure initiated by the UE 4. The 5GS registration procedure is used for example for initial registration, periodic registration and mobility registration. In step 602, the first RAN node 1 receives an RRC Setup Complete message from the UE 4. The RRC Setup Complete message includes AN parameters and a NAS message (registration request message) that includes a Requested NSSAI. The NAS message (registration request message) also includes a Requested NSSAI.

[0053] The first RAN node 1 refers to the Requested NSSAI in the AN parameters received from the UE 4, and compares the S-NSSAIs included in the Requested NSSAI with the S-NSSAIs included in the list of network slices supported by the second RAN node 2. Then, the first RAN node 1 detects one or more S-NSSAIs included in the Requested NSSAI received from the UE 4 and supported by the second RAN node 2. In step 603, the first RAN node 1 sends an INITIAL UE MESSAGE message to the AMF 3. The INITIAL UE MESSAGE message includes the NAS message (registration request message) received from the UE 4. Furthermore, the INITIAL UE MESSAGE message includes a list of one or more S-NSSAIs included in the Requested NSSAI received from the UE 4 and supported by the second RAN node 2.

[0054] Figure 7 shows a specific example of the format of the INITIAL UE MESSAGE message sent in step 603. In the example of Figure 7, the INITIAL UE MESSAGE message includes a Requested S-NSSAI List for Secondary RAT. The Requested S-NSSAI List for Secondary RAT includes a list of one or more S-NSSAIs included in the Requested NSSAI received from UE 4 and supported by the Secondary RAT (i.e., the second RAN node (candidate SN) 2).

[0055] Figure 8 shows another example of the format of the INITIAL UE MESSAGE message sent in step 603. In the example of Figure 8, the INITIAL UE MESSAGE message includes a Requested S-NSSAI List. The Requested S-NSSAI List indicates S-NSSAIs included in the Requested NSSAI received from the UE 4, and indicates whether each S-NSSAI is supported by the Secondary RAT (i.e., the second RAN node (candidate SN) 2) (Secondary RAT Support).

[0056] According to the procedure of Fig. 6, the first RAN node 1 may send slice support information indicating network slices supported by the second RAN node 2 to the AMF 3 via a UE associated signaling message. In one example, the AMF 3 may determine S-NSSAIs allowed for the UE 4 taking into account the list received in step 503. More specifically, the AMF 3 may include one or more S-NSSAIs included in the Requested NSSAI received from the UE 4 and supported by the second RAN node 2 in the Allowed NSSAI of the UE 4 (if it also matches the Subscribed S-NSSAIs of the UE 4).

[0057] Next, configuration examples of the RAN node 1, the RAN node 2, and the AMF 3 according to the above-mentioned embodiments will be described below. FIG. 9 is a block diagram showing a configuration example of the RAN node 1 according to the above-mentioned embodiments. The RAN node 2 may have a similar configuration to that shown in FIG. 9. Referring to FIG. 9, the RAN node 1 includes a Radio Frequency (RF) transceiver 901, a network interface 903, a processor 904, and a memory 905. The RF transceiver 901 performs analog RF signal processing to communicate with UEs. The RF transceiver 901 may include multiple transceivers. The RF transceiver 901 is coupled to an antenna array 902 and a processor 904. The RF transceiver 901 receives modulation symbol data from the processor 904, generates a transmit RF signal, and provides the transmit RF signal to the antenna array 902. The RF transceiver 901 also generates a baseband receive signal based on the receive RF signal received by the antenna array 902, and provides the baseband receive signal to the processor 904. The RF transceiver 901 may include an analog beamformer circuit for beamforming, which may include, for example, multiple phase shifters and multiple power amplifiers.

[0058] The network interface 903 is used to communicate with network nodes (e.g., other RAN nodes, the AMF, and the User Plane Function (UPF)). The network interface 903 may include, for example, a network interface card (NIC) that complies with the IEEE 802.3 series.

[0059] The processor 904 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. The processor 904 may include multiple processors. For example, the processor 904 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.

[0060] For example, digital baseband signal processing by the processor 904 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 904 may include processing of Non-Access Stratum (NAS) messages, RRC messages, MAC CEs, and DCIs.

[0061] The processor 904 may include a digital beamformer module for beamforming, which may include a Multiple Input Multiple Output (MIMO) encoder and a precoder.

[0062] The memory 905 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 905 may include storage located remotely from the processor 904. In this case, the processor 904 may access the memory 905 via the network interface 903 or the I / O interface.

[0063] The memory 905 may store one or more software modules (computer programs) 906 including instructions and data for performing the processes of the RAN node 1 described in the above embodiments. In some implementations, the processor 904 may be configured to read the software modules 906 from the memory 905 and execute them to perform the processes of the RAN node 1 described in the above embodiments.

[0064] In addition, when the RAN node 1 is a Central Unit (eg, gNB-CU) in a C-RAN deployment, the RAN node 1 does not need to include an RF transceiver 901 (and an antenna array 902).

[0065] FIG. 10 shows an example of the configuration of the AMF 3. Referring to FIG. 10, the AMF 3 includes a network interface 1001, a processor 1002, and a memory 1003. The network interface 1001 is used, for example, to communicate with RAN 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 1001 may include, for example, a network interface card (NIC) conforming to the IEEE 802.3 series.

[0066] The processor 1002 may be, for example, a microprocessor, a Micro Processing Unit (MPU), or a Central Processing Unit (CPU). The processor 1002 may include multiple processors.

[0067] The memory 1003 is composed of a volatile memory and a non-volatile memory. The memory 1003 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 1003 may include a storage located away from the processor 1002. In this case, the processor 1002 may access the memory 1003 via the network interface 1001 or an I / O interface.

[0068] The memory 1003 may store one or more software modules (computer programs) 1004 including instructions and data for performing processing by the AMF3 described in the above-mentioned embodiments. In some implementations, the processor 1002 may be configured to read the software modules 1004 from the memory 1003 and execute them to perform the processing of the AMF3 described in the above-mentioned embodiments.

[0069] As described with reference to FIG. 9 and FIG. 10, each of the processors included in the RAN node 1, the RAN node 2, and the AMF 3 according to the above-described embodiment 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 programs may also be provided to a computer by various types of transitory computer readable media. Examples of the temporary computer-readable medium include an electric signal, an optical signal, and an electromagnetic wave. The temporary computer-readable medium can provide the program to the computer via a wired communication path such as an electric wire or an optical fiber, or a wireless communication path.

[0070] <Other embodiments> The above-described embodiments may be implemented independently of each other, or the whole or part of the embodiments may be implemented in appropriate combination.

[0071] The operations of the RAN node 1 and the AMF 3 described in the above embodiments are particularly effective when the second RAN node (candidate SN) 2 is only responsible for the role of an SN of the DC in a non-standalone deployment and does not have a RAN-CN CP interface (i.e., N2 (or NG-C) interface) with any AMF. That is, these operations can enable the UE to utilize network slices supported only by SNs in a non-standalone deployment. However, these embodiments may also be applied to a configuration when the second RAN node (candidate SN) 2 has a RAN-CN CP interface with the AMF 3.

[0072] In the above embodiment, the first RAN node (candidate MN) 1 may further inform the AMF 3 of cell information regarding the cell provided by the second RAN node (candidate SN) 2. More specifically, the first RAN node (candidate MN) 1 may send the cell information to the AMF 3 in the NG Setup procedure or the RAN CONFIGURATION UPDATE procedure. The cell information may include one or any combination of (a) a cell identifier (e.g., NR Physical Cell ID (PCI)), (b) a Tracking Area Code (TAC), and (c) a frequency band (e.g., NR Absolute Radio Frequency Channel Number (NR-ARFCN)) of the cell provided by the second RAN node 2.

[0073] In the above embodiment, the AMF 3 may forward the slice support information received from the first RAN node (candidate MN) 1 to the SMF, which may perform session management for the UE 4 taking into account (or according to) the slice support information.

[0074] The AMF 3 in the above embodiment is not limited to the device name AMF. That is, the AMF 3 in the above embodiment may be a device (for example, another core network node) having a function equivalent to the AMF.

[0075] Furthermore, the above-described embodiment is merely an example 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-described embodiment, and various modifications are possible.

[0076] For example, some or all of the above embodiments may be described as, but are not limited to, the following supplementary notes.

[0077] (Appendix 1) A radio access network (RAN) node device, comprising: At least one memory; at least one processor coupled to the at least one memory; Equipped with The at least one processor is configured to send slice support information indicating network slices supported by other RAN nodes that may be used as secondary nodes in dual connectivity in which the RAN node device operates as a master node to an Access and Mobility management Function (AMF) of a core network. RAN node equipment. (Appendix 2) The at least one processor is configured to send the slice support information to the AMF via a non-User Equipment (UE) related signaling message. 2. The RAN node device according to claim 1. (Appendix 3) The at least one processor is configured to send the slice support information to the AMF in a procedure of setting up or updating application level configuration data necessary for the RAN node device and the AMF to interwork on a control plane interface. 3. A RAN node apparatus as claimed in claim 1 or 2. (Appendix 4) the control plane interface is an NG-C interface; The setup or update procedure is a NG Setup procedure or a RAN Configuration Update procedure; 4. The RAN node device according to claim 3. (Appendix 5) The at least one processor is configured to, in response to receiving an Access Stratum (AS) message including a Non-Access Stratum (NAS) message from a User Equipment (UE), send the slice support information to the AMF via a signaling message for forwarding the NAS message to the AMF. 2. The RAN node device according to claim 1. (Appendix 6) the at least one processor is configured to receive a message from the other RAN node indicating the network slice. 6. A RAN node device according to any one of claims 1 to 5. (Appendix 7) The slice support information indicates network slice identifiers of the network slices supported by the other RAN nodes. 7. A RAN node device according to any one of claims 1 to 6. (Appendix 8) A RAN node device described in any one of Supplementary Notes 1 to 7, wherein the slice support information includes a list of supported network slice identifiers for each Tracking Area (TA) supported by the other RAN node. (Appendix 9) 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 is configured to receive, from a first Radio Access Network (RAN) node, slice support information indicating network slices supported by a second RAN node that may be used as a secondary node in dual connectivity in which the first RAN node operates as a master node. AMF device. (Appendix 10) the at least one processor is configured to, in response to receiving a Non-Access Stratum (NAS) message from a User Equipment (UE) via the first RAN node, determine one or more network slices to be authorized for the UE, taking into account the network slices supported by the second RAN node. 10. The AMF device according to claim 9. (Appendix 11) The at least one processor is configured to receive the slice support information via a non-User Equipment (UE) related signaling message. 11. The AMF device according to claim 9 or 10. (Appendix 12) The at least one processor is configured to receive the slice support information in a setup or update procedure of application level configuration data necessary for the first RAN node and the AMF device to interwork over a control plane interface. 12. The AMF device according to any one of claims 9 to 11. (Appendix 13) the control plane interface is an NG-C interface; The setup or update procedure is a NG Setup procedure or a RAN Configuration Update procedure; 13. The AMF device according to claim 12. (Appendix 14) The at least one processor is configured to receive the slice support information via a signaling message for forwarding a Non-Access Stratum (NAS) message generated by a User Equipment (UE) from the first RAN node to the AMF device. 11. The AMF device according to claim 9 or 10. (Appendix 15) The slice support information indicates a network slice identifier of the network slice supported by the second RAN node. 15. The AMF device according to any one of claims 9 to 14. (Appendix 16) The slice support information includes a list of supported network slice identifiers for each Tracking Area (TA) supported by the second RAN node. Attachment 9 to 15, the AMF device according to any one of claims 9 to 15. (Appendix 17) 1. A method performed by a Radio Access Network (RAN) node device, comprising: sending slice support information to an Access and Mobility management Function (AMF) of a core network, the slice support information indicating network slices supported by other RAN nodes that may be used as secondary nodes in dual connectivity in which the RAN node device acts as a master node; method. (Appendix 18) A method performed by an Access and Mobility management Function (AMF) device, comprising: receiving, from a first Radio Access Network (RAN) node, slice support information indicating network slices supported by a second RAN node that may be used as a secondary node in dual connectivity in which the first RAN node acts as a master node; method. (Appendix 19) A program for causing a computer to perform a method for a radio access network (RAN) node device, comprising: The method comprises sending slice support information to an Access and Mobility management Function (AMF) of a core network, the slice support information indicating network slices supported by other RAN nodes that may be used as secondary nodes in dual connectivity in which the RAN node device acts as a master node. program. (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, from a first Radio Access Network (RAN) node, slice support information indicating network slices supported by a second RAN node that may be used as a secondary node in dual connectivity in which the first RAN node acts as a master node. program.

[0078] This application claims priority based on Japanese Patent Application No. 2020-067094, filed on April 2, 2020, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0079] 1 RAN node 2. RAN Node 3 AMF 905 Memory 906 Modules 1003 Memory 1004 Modules

Claims

1. A radio access network (RAN) node device, comprising: Means for receiving a message including one or more network slice identifiers from a User Equipment (UE); means for receiving slice support information indicating one or more network slice identifiers supported by other RAN nodes that may be used as secondary nodes in dual connectivity in which the RAN node device acts as a master node; A means for sending at least one network slice identifier included in the slice support information to an Access and Mobility management Function (AMF) of a core network; Equipped with The sending means is adapted to determine whether the one or more network slice identifiers included in the slice support information match any of the one or more network slice identifiers included in the message received from the UE; The at least one network slice identifier sent to the AMF includes at least the matched one or more network slice identifiers; RAN node equipment.

2. A method performed by a radio access network (RAN) node device, comprising: Receiving a message from a User Equipment (UE) including one or more network slice identifiers; receiving slice support information indicating one or more network slice identifiers supported by other RAN nodes that may be used as secondary nodes in dual connectivity in which the RAN node device acts as a master node; and Sending at least one network slice identifier included in the slice support information to an Access and Mobility management Function (AMF) of a core network; Equipped with determining whether the one or more network slice identifiers included in the slice support information match any of the one or more network slice identifiers included in the message received from the UE; The at least one network slice identifier sent to the AMF includes at least the matched one or more network slice identifiers; method.

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