Wireless access network nodes, core network nodes, wireless terminals, and methods thereof

Abstract

This radio access network (RAN) node (1) receives, from a core network (4), a first control message (201) that includes a first information element relating to a radio terminal (3). The first information element indicates at least one of the following: the volume of data that can be used by the radio terminal (3); and whether or not one or both of carrier aggregation and dual connectivity are required by the radio terminal (3), or whether or not one or both of carrier aggregation and dual connectivity are permitted in the radio terminal (3). This feature can, for example contribute to providing, to a RAN node, information that is useful for determining whether or not carrier aggregation (CA), dual connectivity (DC), or handovers are required by a radio terminal.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and particularly to connection management or mobility management of a wireless terminal.

Background Art

[0002] In a fifth-generation mobile communication system (5G system), a Radio Access Network (RAN) can receive, from a core network, a per Session Aggregate Maximum Bit Rate (Session-AMBR), a per User Equipment (UE) Aggregate Maximum Bit Rate (UE-AMBR), and a per UE per Slice-Maximum Bit Rate (UE-Slice-MBR) (see, for example, Non-Patent Documents 1 and 2). Each of the Session-AMBR, UE-AMBR, and UE-Slice-MBR includes values for an uplink (UL) and a downlink (DL).

[0003] The Session-AMBR limits an expected aggregate bit rate provided over all non-Guaranteed Bit Rate (non-GBR) Quality of Service (QoS) Flows of a specific Protocol Data Unit (PDU) Session. The RAN uses the Session-AMBR to calculate its UE-AMBR.

[0004] UE-AMBR limits the aggregated bitrate expected to be provided across all Non-GBR QoS flows of a wireless terminal (UE). The RAN enforces UE-AMBR for each UE at UL and DL for Non-GBR QoS flows. The RAN sets its UE-AMBR to the sum of the Session-AMBRs of all PDU sessions with active user planes for that RAN, up to the UE-AMBR received from the core network.

[0005] UE-Slice-MBR limits the aggregated bitrate expected to be provided across all GBR and non-GBR QoS flows corresponding to PDU sessions of a UE with an active user plane within the same network slice (Single Network Slice Selection Assistance Information (S-NSSAI)). If a supporting RAN receives a UE-Slice-MBR for an S-NSSAI from the core network for a UE, the RAN applies this UE-Slice-MBR to all PDU sessions of that UE with an active user plane corresponding to that S-NSSAI, if feasible.

[0006] The master node (MN) of a dual connectivity (DC) can determine the Session-AMBR limit, UE-AMBR limit, and UE-Slice-MBR limit to be allocated to the secondary node (SN) of the DC, and send these to the SN (see, for example, Non-Patent Documents 3 and 4). [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] 3GPP TS 23.501 V17.4.0 (2022-03) "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System architecture for the 5G System (5GS); Stage 2 (Release 17)", March 2022 [Non-Patent Document 2] 3GPP TS 38.413 V17.0.0 (2022-04) "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NG-RAN; NG Application Protocol (NGAP) (Release 17)", April 2022 [Non-Patent Document 3] 3GPP TS 37.340 V17.0.0 (2022-03) "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and NR; Multi-connectivity; Stage 2 (Release 17)", March 2022 [Non-Patent Document 4] 3GPP TS 38.423 V17.0.0 (2022-04) "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NG-RAN; Xn application protocol (XnAP) (Release 17)", April 2022 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The inventors investigated the determination of carrier aggregation (CA), data center (DC), and handover by RAN nodes and identified various challenges. One of these challenges concerns providing RAN nodes with information useful for determining whether CA, DC, or handover is required for the UE. Specifically, it may be preferable for the core network to be able to provide such information to the RAN nodes.

[0009] Another problem encountered by the inventors concerns the use of maximum bitrate parameters (e.g., Session-AMBR, UE-AMBR, or UE-Slice-MBR) provided by the core network by RAN nodes to determine whether CA, DC, or handover is necessary. For example, if the UE-AMBR for a UE is changed or updated for any reason, the core network provides the RAN node with the updated value of the UE-AMBR. If the updated value of the UE-AMBR is small, starting a new DC for that UE or continuing an existing DC by the RAN node may result in wasted computing and radio resources in the RAN. Similar problems can arise if the Session-AMBR or UE-Slice-MBR is updated. Similar problems can arise when starting or continuing a CA. Similar problems can arise when handover. For example, if the updated value of the UE-AMBR for a UE is small, moving that UE from a high-speed communication-enabled cell to another cell may be beneficial from the standpoint of efficient use of radio resources.

[0010] One of the objectives that the embodiments disclosed herein seek to achieve is to provide apparatus, methods, and programs that contribute to solving at least one of several problems, including those described above. It should be noted that this objective is only one of several objectives that the embodiments disclosed herein seek to achieve. Other objectives or problems and novel features will be revealed in this specification or in the accompanying drawings. [Means for solving the problem]

[0011] In a first embodiment, a wireless access network node 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 first control message from a core network, which includes a first information element relating to a wireless terminal. The first information element indicates at least one of the following: the amount of data available to the wireless terminal; or whether carrier aggregation and / or dual connectivity are required or permitted for the wireless terminal.

[0012] In a second embodiment, the method performed by a radio access network node includes receiving a first control message from the core network that comprises a first information element relating to a radio terminal. The first information element indicates at least one of the following: the amount of data available to the radio terminal; or whether carrier aggregation and / or dual connectivity are required or permitted for the radio terminal.

[0013] In a third embodiment, the core network node 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 transmit a first control message to a radio access network node, the first information element comprising a first information element relating to a radio terminal, the amount of data available to the radio terminal, or at least one of the following: whether carrier aggregation and / or dual connectivity are required or permitted for the radio terminal.

[0014] In a fourth aspect, the method performed by the core network node includes transmitting a first control message to the radio access network node, the first information element comprising a first information element relating to a radio terminal, the amount of data available to the radio terminal; or at least one of the following: whether carrier aggregation and / or dual connectivity are required or permitted for the radio terminal.

[0015] In a fifth embodiment, the wireless terminal 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 transmit a control message to the core network that includes an information element indicating whether carrier aggregation and / or dual connectivity are required.

[0016] In the sixth embodiment, the method performed by the wireless terminal includes transmitting a control message to the core network that includes an informational element indicating whether carrier aggregation and / or dual connectivity are required.

[0017] In a seventh embodiment, the wireless access network node 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 obtain one or more maximum bitrate parameters that limit the aggregated bitrate of a plurality of QoS flows relating to a wireless terminal. The at least one processor is configured to determine, based on the one or more maximum bitrate parameters, whether carrier aggregation and / or dual connectivity are required for the wireless terminal.

[0018] In the eighth aspect, the method performed by the wireless access network node includes the following steps: (a) Obtaining one or more maximum bitrate parameters that limit the aggregated bitrate of a plurality of QoS flows related to a wireless terminal, and (b) Based on the one or more maximum bitrate parameters, determining whether one or both of carrier aggregation and dual connectivity are required for the wireless terminal.

[0019] In a ninth aspect, a radio access network node 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 obtain one or more maximum bitrate parameters that limit the aggregated bitrate of a plurality of QoS flows related to a wireless terminal. The at least one processor is configured to determine whether to hand over the wireless terminal from a current serving cell to another cell based on the one or more maximum bitrate parameters.

[0020] In a tenth aspect, a method performed by a radio access network node includes the following steps: (a) Obtaining one or more maximum bitrate parameters that limit the aggregated bitrate of a plurality of QoS flows related to a wireless terminal, and (b) Based on the one or more maximum bitrate parameters, determining whether to hand over the wireless terminal from a current serving cell to another cell.

[0021] In an eleventh aspect, a program includes a set of instructions (software code) for causing a computer to perform a method according to any of the above aspects when loaded into the computer.

Advantages of the Invention

[0022] According to the above aspect, an apparatus, a method, and a program can be provided that contribute to solving at least one of a plurality of problems related to the determination of CA, DC, and handover by a RAN node including the above-described problems.

Brief Description of the Drawings

[0023] [Figure 1] It is a diagram showing a configuration example of a wireless communication system according to an embodiment. [Figure 2] It is a sequence diagram showing an example of signaling according to an embodiment. [Figure 3] It is a flowchart showing an example of the operation of a RAN node according to an embodiment. [Figure 4] It is a flowchart showing an example of the operation of a RAN node according to an embodiment. [Figure 5] It is a flowchart showing an example of the operation of a RAN node according to an embodiment. [Figure 6] It is a flowchart showing an example of the operation of a RAN node according to an embodiment. [Figure 7] It is a flowchart showing an example of the operation of a RAN node according to an embodiment. [Figure 8] It is a flowchart showing an example of the operation of a RAN node according to an embodiment. [Figure 9] It is a flowchart showing an example of the operation of a RAN node according to an embodiment. [Figure 10] It is a flowchart showing an example of the operation of a RAN node according to an embodiment. [Figure 11] It is a flowchart showing an example of the operation of a RAN node according to an embodiment. [Figure 12] It is a flowchart showing an example of the operation of a RAN node according to an embodiment. [Figure 13] It is a sequence diagram showing an example of signaling according to an embodiment. [Figure 14] It is a flowchart showing an example of the operation of a core network node according to an embodiment. [Figure 15]This flowchart shows an example of the operation of a RAN node according to the present invention. [Figure 16] This is a sequence diagram showing an example of the operation of a RAN node and a core network node according to the embodiment. [Figure 17] This is a sequence diagram showing an example of the operation of two RAN nodes according to the embodiment. [Figure 18] This flowchart shows an example of the operation of a RAN node according to the present invention. [Figure 19] This flowchart shows an example of the operation of a RAN node according to the present invention. [Figure 20] This flowchart shows an example of the operation of a RAN node according to the present invention. [Figure 21] This flowchart shows an example of the operation of a RAN node according to the present invention. [Figure 22] This flowchart shows an example of the operation of a RAN node according to the present invention. [Figure 23] This flowchart shows an example of the operation of a RAN node according to the present invention. [Figure 24] This flowchart shows an example of the operation of a RAN node according to the present invention. [Figure 25] This is a block diagram showing an example configuration of a RAN node according to the embodiment. [Figure 26] This is a block diagram showing an example configuration of a wireless terminal according to the embodiment. [Figure 27] This block diagram shows an example configuration of a core network node according to the embodiment. [Modes for carrying out the invention]

[0024] The following describes specific embodiments in detail with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numeral, and redundant explanations are omitted where necessary for clarity.

[0025] The multiple embodiments described below can be implemented independently or in combination as appropriate. These multiple embodiments have novel features that differ from each other. Therefore, these multiple embodiments contribute to solving different objectives or problems and contribute to producing different effects.

[0026] The embodiments described below primarily focus on the 3rd Generation Partnership Project (3GPP®) Long Term Evolution (LTE) system and the 5th Generation Mobile Communication System (5G system). However, these embodiments may also be applied to other wireless communication systems that support 3GPP's CA, DC, and handover and similar technologies. The term LTE as used herein includes improvements and advancements of LTE and LTE-Advanced to enable interworking with 5G Systems, unless otherwise specified.

[0027] As used herein, depending on the context, “(if)” may be interpreted as meaning “when,” “at or around the time,” “after,” “upon,” “in response to determining,” “in accordance with a determination,” or “in response to detecting.” These expressions may be interpreted as having the same meaning depending on the context.

[0028] First, the configuration and operation of several network elements common to multiple embodiments will be described. Figure 1 shows an example configuration of a wireless communication system according to several embodiments. In the example in Figure 1, the wireless communication system includes RAN node 1, RAN node 2, and wireless terminal 3. Hereinafter, wireless terminal 3 may be referred to as User Equipment (UE). Each element (network function) shown in Figure 1 can be implemented, for example, as a network element on dedicated hardware, as a running software instance on dedicated hardware, or as an instantiated virtualization function on an application platform.

[0029] RAN node 1 may be a Central Unit (e.g., eNB-CU, or gNB-CU) in a cloud RAN (C-RAN) deployment, or a combination of a CU and one or more Distributed Units (e.g., eNB-DUs, or gNB-DUs). C-RAN is also called a CU / DU split. Furthermore, a CU may include a Control Plane (CP) Unit (e.g., gNB-CU-CP) and one or more User Plane (UP) Units (e.g., gNB-CU-UP). Therefore, RAN node 1 may be a CU-CP, or a combination of a CU-CP and a CU-UP. Similarly, RAN node 2 may be a CU, or a combination of a CU and one or more DUs. RAN node 2 may be a CU-CP, or a combination of a CU-CP and a CU-UP.

[0030] Each of RAN nodes 1 and 2 may be an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (EUTRAN) node or a Next-generation Radio Access Network (NG-RAN) node. An EUTRAN node may be an eNB or an en-gNB. An NG-RAN node may be a gNB or an ng-eNB. An en-gNB is a node that provides NR user plane and control plane protocol termination to the UE and operates as a secondary node (SN) of E-UTRA-NR Dual Connectivity (EN-DC). An ng-eNB is a node that provides E-UTRA user plane and control plane protocol termination to the UE and connects to 5GC via an NG interface. The Radio Access Technology (RAT) of RAN node 1 may differ from that of RAN node 2.

[0031] RAN Node 1 and RAN Node 2 may communicate with each other via an inter-node interface (ie, X2 interface or Xn interface) 103. RAN Node 1 and RAN Node 2 may operate as the master node (MN) and secondary node (SN) of dual connectivity, respectively. Hereinafter, RAN Node 1 may be referred to as MN1 and RAN Node 2 as SN2. Wireless terminal (UE) 3 may communicate with MN1 and SN2 via air interfaces 101 and 102 to perform dual connectivity for a Master Cell Group (MCG) and a Secondary Cell Group (SCG).

[0032] This dual connectivity may also be Multi-Radio Dual Connectivity (MR-DC). MR-DC includes E-UTRA-NR Dual Connectivity (EN-DC), NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC), NR-E-UTRA Dual Connectivity (NE-DC), and NR-NR Dual Connectivity (NR-DC). Accordingly, MN1 may be a master eNB (in EN-DC), a master ng-eNB (in NGEN-DC), or a master gNB (in NR-DC and NE-DC). Similarly, SN2 may be an en-gNB (in EN-DC), a secondary ng-eNB (in NE-DC), or a secondary gNB (in NR-DC and NGEN-DC). In EN-DC, UE3 is connected to an eNB operating as MN1 and to an en-gNB operating as SN2. In NGEN-DC, UE3 is connected to an ng-eNB operating as MN1 and to a gNB operating as SN2. In NE-DC, UE3 is connected to a gNB operating as MN1 and to an ng-eNB operating as SN2. In NR-DC, UE3 is connected to one gNB (or gNB-DU) operating as MN1 and to another gNB (or gNB-DU) operating as SN2.

[0033] The MCG is a group of serving cells associated with (or provided by) MN1, including Special Cells (SpCells) (i.e., Primary Cells (PCells)) and optionally one or more Secondary Cells (SCells). The SCG, on the other hand, is a group of serving cells associated with (or provided by) SN2, including Primary SCG Cells (PSCells) and optionally one or more Secondary Cells (SCells). A PSCell is a SpCell of the SCG and supports Physical Uplink Control Channel (PUCCH) transmission and contention-based Random Access.

[0034] As used herein, the terms “Primary SCG Cell” and its abbreviation “PSCell” mean a cell that is part of a cell group provided by a dual connectivity SN, has an uplink component carrier, and is configured with uplink control channel (e.g., PUCCH) resources. Specifically, the terms “Primary SCG Cell” and its abbreviation “PSCell” may mean a Primary SCG Cell of a cell group provided by a 5G NR-supporting SN (e.g., en-gNB in ​​EN-DC, gNB in ​​NGEN-DC, or gNB in ​​NR-DC), or a Primary SCell of a cell group provided by an E-UTRA-supporting SN (e.g., eNB in ​​LTE DC, or ng-eNB in ​​NE-DC).

[0035] RAN node 1 communicates with core network 4 via interface 104. RAN node 2 communicates with core network 4 via interface 105. Interface 104 includes a control plane interface (or connection) and a user plane interface (or connection). Interface 105 includes a user plane interface and may also include a control plane interface. The control plane interface may be an NG-C or S1-Mobility Management Entity (MME) interface. The user plane interface may be an NG-U or S1-U interface.

[0036] Core network 4 may be a 5G Core (5GC), an Evolved Packet Core (EPC), or a combination thereof. Core network 4 includes one or more core network nodes. These core network nodes include one or more control plane nodes and one or more user plane (or data plane) nodes. In the case of a 5G system, the control plane nodes include the Access and Mobility Management Function (AMF), Session Management Function (SMF), and other nodes (e.g., Unified Data Management (UDM) and Policy Control Function (PCF)), and the user plane nodes include the User Plane Function (UPF). In the case of an LTE system, the control plane nodes include the Mobility Management Entity (MME) and other nodes (e.g., Home Subscriber Server (HSS) and Policy and Charging Rules Function (PCRF)), and the user plane nodes include the Serving Gateway (S-GW) and Packet Data Network Gateway (P-GW).

[0037] The configuration example in Figure 1 is just one example and can be modified in various ways. For example, the MN and SN functions of dual connectivity may be provided by a single RAN node (e.g., RAN node 1). Specifically, NR-DC can also be used when UE3 is connected only to RAN node 1 (i.e., gNB) which operates as both MN and SN and constitutes both MCG and SCG. In this case, UE3 may be connected to two gNB-DUs, one providing MCG and the other SCG, and these two gNB-DUs may be connected to a single gNB-CU that operates as both MN and SN. Alternatively, UE3 may be connected to a single gNB-DU that provides both MCG and SCG, and this gNB-DU may be connected to a single gNB-CU that operates as both MN and SN.

[0038] In this specification, the terms MN Radio Resource Control (RRC) Reconfiguration message and SN RRC Reconfiguration message are used. These terms are used for convenience to distinguish RRC (Connection) Reconfiguration messages generated by MN from RRC (Connection) Reconfiguration messages generated by SN. Therefore, an MN RRC Reconfiguration message may simply be called an RRC Reconfiguration message or an RRC Connection Reconfiguration message. Similarly, an SN RRC Reconfiguration message may simply be called an RRC Reconfiguration message or an RRC Connection Reconfiguration message.

[0039] <First Embodiment> This embodiment provides improved signaling between the RAN and the core network, and operation of the RAN based on the improved signaling. The configuration example of the wireless communication system according to this embodiment may be the same as the example shown in Figure 1.

[0040] Figure 2 shows an example of signaling between RAN node 1 and core network node 5. Core network node 5 is a control plane node included in core network 4. If core network 4 is 5GC, core network node 5 may be AMF, SMF, or a combination thereof, and the signaling may be NG Application Protocol (NGAP) signaling or messages. If core network 4 is EPC, core network node 5 may be MME, and the signaling may be S1AP signaling or messages.

[0041] In step 201, the core network node 5 sends a first control message to the RAN node 1 that includes a first information element relating to the wireless terminal 3. The first control message may be an NGAP message or an S1AP message. The first information element indicates at least one of the following: the amount of data available to the wireless terminal 3; or whether one or both of CA and DC are required (or permitted) for the wireless terminal 3.

[0042] The core network node 5 may send a first control message containing a first information element when establishing a new control connection for the wireless terminal 3 between the core network node 5 and the RAN node 1. In this case, the first control message may be an NGAP: INITIAL CONTEXT SETUP REQUEST message. Alternatively, the core network node 5 may send a first control message containing the updated first information element in response to an update or modification of the information contained in the first information element. In this case, the first control message may be an NGAP: UE CONTEXT MODIFICATION REQUEST message. Alternatively, the core network node 5 may send a first control message containing a first information element when a PDU Session for the wireless terminal 3 is established. In this case, the first control message may be an NGAP: PDU SESSION RESOURCE SETUP REQUEST message.

[0043] The first information element may at least indicate the amount of data available to the wireless terminal 3. In this case, the name of the first information element is not limited, but may be, for example, the UE's Available Data information element. The information element may be of integer type and may have an integer value between, for example, 0 and 1,000,000,000,000 to represent the size (bytes) of the data amount.

[0044] The amount of data available to wireless terminal 3 may be the remaining amount of data available to the user (subscriber) using wireless terminal 3 by the end of the current month. In other words, the amount of data available to wireless terminal 3 may indicate the remaining amount of data up to the monthly data limit based on the contract (subscription). Alternatively, the amount of data available to wireless terminal 3 may indicate the remaining amount of data that the user of wireless terminal 3 can consume over a predetermined period (e.g., 3 days, 1 week, 1 month).

[0045] The first information element may at least indicate whether CA and DC, or both, are required (or permitted) for the wireless terminal 3. In this case, the name of the first information element may be, but is not limited to, the NR-DC / CA Enforceability information element. The information element may be of enumerated type and may indicate NR-DC & CA Enforceable, Only NR-DC Enforceable, Only CA Enforceable, or NR-DC & CA Not Enforceable.

[0046] In some implementations, depending on the communication status of the user of wireless terminal 3, the core network node 5 may provide the RAN node 1 with a (updated) first information element indicating that one or both of the CA and DC are not required or permitted for wireless terminal 3. Specifically, if it is detected that the user of wireless terminal 3 is about to run out of data capacity that can be used or consumed within a predetermined period (e.g., 3 days, 1 week, 1 month), the core network node 5 may provide the RAN node 1 with a (updated) first information element indicating that one or both of the CA and DC are not required or permitted for wireless terminal 3. Alternatively, if it is detected that the user of wireless terminal 3 has run out of data capacity that can be used or consumed within a predetermined period (e.g., 3 days, 1 week, 1 month), the core network node 5 may provide the RAN node 1 with a (updated) first information element indicating that one or both of the CA and DC are not required or permitted for wireless terminal 3. On the other hand, if the data capacity available to the user of wireless terminal 3 is restored for reasons such as the start of a new predetermined period, the core network node 5 may provide the RAN node 1 with an (updated) first information element indicating that one or both of CA and DC are required or permitted for wireless terminal 3.

[0047] In some implementations, depending on other factors such as congestion in the core network 4, the core network node 5 may provide the RAN node 1 with a (updated) first information element indicating that one or both of the CA and DC are not required or permitted for the wireless terminal 3.

[0048] The first information element may be used by RAN node 1 to determine whether CA and DC, or both, are required for the wireless terminal 3. Specifically, RAN node 1 may decide whether to perform or start CA and DC, or both, for the wireless terminal 3, based on or relying on the first information element, or using or considering the first information element. Furthermore, or alternatively, RAN node 1 may decide whether to stop CA and DC, or both, that are currently running for the wireless terminal 3, based on or relying on the first information element, or using or considering the first information element.

[0049] CA initiation may be performed by adding or configuring one or more SCells, or by activating one or more SCells that have already been added or configured. Adding and releasing SCell(s) may be performed by RAN node 1 sending an RRC (Connection) Reconfiguration message to wireless terminal 3. Activating SCell(s) may be performed by RAN node 1 sending a SCell Activation / Deactivation Medium Access Control (MAC) Control Element (CE) to wireless terminal 3.

[0050] CA deactivation may be performed by releasing one or more SCells, or by deactivating one or more SCells. Releasing SCell(s) may be performed by RAN node 1 sending an RRC (Connection) Reconfiguration message to radio terminal 3. Deactivating SCell(s) may be performed by RAN node 1 sending an SCell Activation / Deactivation MAC CE to radio terminal 3. RAN node 1 may provide radio terminal 3 with updated measurement settings via the RRC (Connection) Reconfiguration message so as to exclude the frequencies of the released SCell(s) from the measurement target of radio terminal 3.

[0051] DC activation may be performed by adding or configuring a new SN and SCG, or by activating an added or configured SCG. Adding an SN and SCG may be performed by MN (e.g., RAN node 1) initiating the SN Addition procedure. This SN Addition procedure includes sending an S-NODE ADDITION REQUEST message from MN (e.g., RAN node 1) to SN (e.g., RAN node 2). This SN Addition procedure further includes sending an MN RRC Reconfiguration message from RAN node 1 to wireless terminal 3, which includes an SN RRC configuration message generated by RAN node 2. SCG activation may be performed by sending an RRC message, MAC CE, or Downlink Control Information (DCI) from MN (e.g., RAN node 1) or SN (e.g., RAN node 2) to wireless terminal 3.

[0052] DC shutdown may be performed by releasing the SN and SCG, or by deactivating the SCG. Releasing the SN and SCG may be performed by the MN (e.g., RAN node 1) initiating the SN Release procedure. This SN Release procedure includes sending an S-NODE RELEASE REQUEST message from the MN (e.g., RAN node 1) to the SN (e.g., RAN node 2). In this SN Release procedure, the MN (e.g., RAN node 1) may, if necessary, indicate to the radio terminal 3 via an MN RRC Reconfiguration message that the radio terminal 3 should release all SCG settings. The MN (e.g., RAN node 1) may provide the radio terminal 3 with updated measurement settings via an RRC (Connection) Reconfiguration message so as to exclude the frequencies of the released SCG from the measurement target of the radio terminal 3.

[0053] In the SN Release procedure, MN (e.g., RAN node 1) may include a Cause information element in the S-NODE RELEASE REQUEST message that indicates the reason for the SN release. This Cause information element may be set to a value that means, for example, that wireless terminal 3 is about to use up its contracted data allowance, or that wireless terminal 3 has used up its contracted data allowance. As an example, this Cause information element may be set to "UE Available Data Reaches Maximum".

[0054] Consider the case where the first information element indicates the amount of data available to the wireless terminal 3. In this case, if the amount of data falls below a first threshold, RAN node 1 may decide or recognize that it will not perform (or start) one or both CA and DC for the wireless terminal 3. Similarly, if the amount of data falls below a first threshold, RAN node 1 may stop one or both of the CA and DC currently running for the wireless terminal 3. Conversely, if the amount of data exceeds a second threshold, RAN node 1 may decide or recognize that it can perform (or start) one or both CA and DC for the wireless terminal 3. Similarly, if the amount of data exceeds a second threshold, RAN node 1 may continue one or both of the CA and DC currently running for the wireless terminal 3. The second threshold may be the same as or different from the first threshold.

[0055] Consider the case where the first information element indicates whether CA and DC, or both, are required (or permitted) for the radio terminal 3. In this case, if the first information element indicates that CA and DC, or both, are not required or prohibited, RAN node 1 may decide or recognize that it will not perform (or start) CA and DC, or both, for the radio terminal 3. Alternatively, RAN node 1 may stop one or both of the CA and DC currently running for the radio terminal 3. Conversely, if the first information element indicates that CA and DC, or both, are required or permitted, RAN node 1 may decide or recognize that it can perform (or start) CA and DC, or both, for the radio terminal 3. Alternatively, RAN node 1 may continue one or both of the CA and DC currently running for the radio terminal 3.

[0056] The first information element may be used by RAN node 1 to determine whether or not to hand over the wireless terminal 3 from the current serving cell to another cell. Specifically, RAN node 1 may decide whether or not to hand over the wireless terminal 3 based on or relying on the first information element, or using or considering the first information element.

[0057] Consider the case where the first information element indicates the amount of data available to the wireless terminal 3. In this case, if the amount of data falls below the first threshold, RAN node 1 may decide to hand over the wireless terminal 3 from the current serving cell that supports high-speed communication to another cell. Conversely, if the amount of data exceeds the second threshold, RAN node 1 may decide to hand over the wireless terminal 3 from the current serving cell to another cell that supports high-speed communication. The second threshold may be the same as or different from the first threshold. For example, the cell that supports high-speed communication may be a cell operating in the millimeter wave (mmWave) (FR2) band, and the other cell may be a cell operating in the sub-6 GHz (FR1) band. Alternatively, the cell that supports high-speed communication may be a 5G New Radio (NR) cell, and the other cell may be an LTE cell.

[0058] The first information element may be used by RAN node 1 to derive a second information element to be transmitted to RAN node 2. Specifically, RAN node 1, acting as the MN of the DC for wireless terminal 3, may derive a second information element based on the first information element and send a second control message containing the second information element to RAN node 2, acting as the SN of the DC. In one example, RAN node 1 may separate the amount of data indicated by the first information element received from core network node 5 into an amount of data allocated to the MN and an amount of data allocated to the SN. Then, RAN node 1 may generate a second information element indicating the amount of data allocated to the SN and send a second control message containing the second information element to RAN node 2, acting as the SN. In another example, RAN node 1 may transparently include the information indicated by the first information element received from core network node 5 in the second information element. In other words, RAN node 1 may include the information indicated by the first information element received from core network node 5 in the second information element without modification.

[0059] The signaling described with reference to Figure 2 enables the provision of useful information to RAN node 1 for determining whether CA, DC, or handover is required for wireless terminal 3.

[0060] Figures 3 to 10 provide examples of the operation of RAN node 1, and Figures 11 and 12 provide examples of the operation of RAN node 2. Below, examples of the operation of RAN nodes 1 and 2 will be explained with reference to these figures.

[0061] Figure 3 shows an example of the operation of RAN node 1. Step 301 corresponds to step 201 in Figure 2. Specifically, in step 301, RAN node 1 receives a first control message from core network 4 that includes a first information element relating to wireless terminal 3. The first information element indicates at least one of the following: the amount of data available to wireless terminal 3; or whether CA and DC, or both, are required (or permitted) for wireless terminal 3.

[0062] In step 302, RAN node 1 determines, based on the first information element, whether CA and DC, or both, are required for the wireless terminal 3. In other words, RAN node 1 determines, based on, relying on, using, or considering the information provided in the first information element, whether CA and DC, or both, are required for the wireless terminal 3. The method of this determination has already been explained, so a redundant explanation will be omitted here.

[0063] If a DC is not required for wireless terminal 3, RAN node 1 may operate in a way that does not start a DC for wireless terminal 3, or it may stop any DC that is currently running for wireless terminal 3. If a CA is not required for wireless terminal 3, RAN node 1 may operate in a way that does not start a CA for wireless terminal 3, or it may stop any CA that is currently running for wireless terminal 3.

[0064] Figure 4 shows an example of the operation of RAN node 1. Step 401 is similar to step 301 in Figure 3.

[0065] In step 402, RAN node 1 decides whether to perform (or initiate) one or both CA and DC for wireless terminal 3, based on the first information element. In other words, RAN node 1 decides whether to perform (or initiate) one or both CA and DC for wireless terminal 3, based on, relying on, using, or considering the information provided in the first information element. The method of this decision has already been explained, so a redundant explanation will be omitted here.

[0066] Figure 5 shows an example of the operation of RAN node 1. Step 501 is similar to step 301 in Figure 3, except that in step 501, while RAN node 1 is performing CA for wireless terminal 3, RAN node 1 receives a first control message containing a first information element from core network 4.

[0067] In step 502, RAN node 1 decides, based on the first information element, whether to stop using some or all of the SCells of one or more CAs that are running for the wireless terminal 3. The method of this decision may be the same as any of the methods already described. Multiple thresholds may be used for this decision. Specifically, consider the case where the first information element indicates the amount of data available to the wireless terminal 3. In this case, if the amount of data is below the first threshold, RAN node 1 may release (or deactivate) some of the SCells set (or activated) in the CA. If the amount of data is below a second threshold that is smaller than the first threshold, RAN node 1 may release (or deactivate) all of the SCells set (or activated) in the CA.

[0068] Figure 6 shows an example of the operation of RAN node 1. Step 601 is similar to step 301 in Figure 3, except that in step 601, while RAN node 1 is performing DC for wireless terminal 3, RAN node 1 receives a first control message containing a first information element from core network 4.

[0069] In step 602, RAN node 1 decides, based on the first information element, whether to stop using some or all of the one or more SCGs of the DC that are running for the wireless terminal 3. The method of this decision may be the same as any of the methods already described. Multiple thresholds may be used for this decision. Specifically, consider the case where the first information element indicates the amount of data available to the wireless terminal 3. In this case, if the amount of data is below the first threshold, RAN node 1 may release (or deactivate) some of the SCGs set (or activated) in the DC. If the amount of data is below a second threshold which is smaller than the first threshold, RAN node 1 may release (or deactivate) all of the SCGs set (or activated) in the DC.

[0070] Figure 7 shows an example of the operation of RAN node 1. Step 701 is similar to step 301 in Figure 3, except that in step 701, the first information element indicates at least the amount of data available to wireless terminal 3.

[0071] In step 702, if the amount of data indicated by the first information element is below a first threshold, RAN node 1 determines or recognizes that DC is not required for wireless terminal 3. In step 703, if the amount of data indicated by the first information element is below a second threshold which is smaller than the first threshold, RAN node 1 determines or recognizes that neither DC nor CA is required for wireless terminal 3. The order of steps 702 and 703 is not limited. Steps 702 and 703 may be performed substantially simultaneously, or step 703 may be performed before step 702.

[0072] Figure 8 shows an example of the operation of RAN node 1. Step 801 is similar to step 301 in Figure 3, except that in step 801, while RAN node 1 is performing one or both CA and DC for wireless terminal 3, RAN node 1 receives a first control message from core network 4 that includes a first information element. In addition, in step 801, the first information element indicates at least the amount of data available to wireless terminal 3.

[0073] In step 802, if the amount of data indicated by the first information element falls below the first threshold, RAN node 1 stops either or both CA and DC for wireless terminal 3.

[0074] In step 803, RAN node 1 does not initiate either or both CA and DC for wireless terminal 3 until the amount of data exceeds a second threshold greater than the first threshold. In other words, RAN node 1 stops either or both CA and DC for wireless terminal 3 until it receives a new control message from core network 4 indicating an updated value for the amount of data exceeding the second threshold.

[0075] Figure 9 shows an example of the operation of RAN node 1. Step 901 is similar to step 301 in Figure 3.

[0076] In step 902, RAN node 1 decides, based on the first information element, whether or not to hand over wireless terminal 3 from the current serving cell to another cell. The method of this decision may be the same as any of the methods already described.

[0077] Figure 10 shows an example of the operation of RAN node 1. Step 1001 is similar to step 301 in Figure 3.

[0078] In step 1002, RAN node 1, acting as MN, sends a second control message to RAN node 2, acting as SN for the DC for wireless terminal 3, which includes a second information element derived based on the first information element. Note that "RAN node 1 acting as MN" may be a RAN node capable of acting as MN, i.e., an MN candidate before the DC is started. Alternatively, "RAN node 1 acting as MN" may be a RAN node that is acting as MN after the DC has been started. Similarly, "RAN node 2 acting as SN" may be a RAN node capable of acting as SN, i.e., an SN candidate before the DC is started. Alternatively, "RAN node 2 acting as SN" may be a RAN node that is acting as SN after the DC has been started. The method for deriving or generating the second information element may be the same as any of the methods already described. The second control message may be an XnAP message. More specifically, the second control message may be an XnAP: S-NODE ADDITION REQUEST message or an XnAP: S-NODE MODIFICATION REQUEST message.

[0079] Figure 11 shows an example of the operation of RAN node 2. In step 1101, RAN node 2, acting as the SN of the DC, receives a second control message from RAN node 1, acting as the MN, which contains a second information element about the wireless terminal 3.

[0080] In step 1102, RAN node 2 decides, based on the second information element, whether to stop using some or all of the SCells of one or more CAs running within the SCG for the radio terminal 3. The method of this decision may be similar to any of the methods already described for CAs at RAN node 1.

[0081] Figure 12 shows an example of the operation of RAN node 2. In step 1201, RAN node 2, acting as the SN of the DC, receives a second control message from RAN node 1, acting as the MN, which contains a second information element about the wireless terminal 3.

[0082] In step 1202, RAN node 2 decides, based on the second information element, whether to deactivate some or all of the SCGs of one or more DCs currently running for the wireless terminal 3. The method of this decision may be the same as any of the methods already described for DCs at RAN node 1. If it decides to deactivate an SCG, RAN node 2 may deactivate the SCG. Alternatively, if it decides to deactivate an SCG, RAN node 2 may request RAN node 1, which is acting as the MN, to release the SN.

[0083] <Second Embodiment> This embodiment provides a variation of the first embodiment. The configuration example of the wireless communication system according to this embodiment is the same as the example described with reference to Figure 1.

[0084] Figure 13 shows an example of signaling between a wireless terminal 3 and a core network node 5. In step 1301, the wireless terminal 3 sends a control message to the core network node 5 that includes an information element indicating whether CA and DC, or both, are required. The name of this information element is not limited, but may be, for example, a DC / CA Necessity information element.

[0085] If core network 4 is 5GC, then core network node 5 may be AMF, SMF, or a combination thereof. In this case, the control message in step 1301 may be a Non-Access Stratum (NAS) message. More specifically, the control message may be a REGISTRATION REQUEST message, a SERVICE REQUEST message, or a UL NAS TRANSPORT message sent from wireless terminal (UE) 3 to AMF. Alternatively, the control message may be a PDU SESSION ESTABLISHMENT REQUEST message or a PDU SESSION MODIFICATION REQUEST message sent from wireless terminal (UE) 3 to SMF. The PDU SESSION ESTABLISHMENT REQUEST message and PDU SESSION MODIFICATION REQUEST message for session management are sent from wireless terminal 3 to AMF via a UL NAS TRANSPORT message and forwarded to SMF by AMF.

[0086] The wireless terminal 3 may send the control message (e.g., REGISTRATION REQUEST message) of step 1301 when requesting registration with the core network 4. Alternatively, the wireless terminal 3 may send the control message (e.g., SERVICE REQUEST message) of step 1301 when requesting the establishment of a secure connection with the AMF. Alternatively, the wireless terminal 3 may send the control messages (e.g., UL NAS TRANSPORT message and PDU SESSSION ESTABLISHMENT REQUEST message) of step 1301 when requesting the establishment of a PDU session.

[0087] The information elements carried in the control message of step 1301 may be used by the core network node 5 to inform the RAN node 1 whether or not CA and DC, or both, are required or permitted for the wireless terminal 3. More specifically, as shown in Figure 14, the first information elements described in the first embodiment may be determined or generated based on, relying on, using or considering, the information elements received from the wireless terminal 3 (e.g., DC / CA Necessity).

[0088] Figure 14 shows an example of the operation of core network node 5. Step 1401 corresponds to step 1301 in Figure 13. Specifically, core network node 5 receives a control message from wireless terminal 3 that includes information elements indicating whether CA and DC are required or not. In step 1402, core network node 5 determines a first information element to be sent to RAN node 1 based on the information elements received from wireless terminal 3.

[0089] Specifically, if the information element from the wireless terminal 3 indicates that CA is not required, the core network node 5 may provide the RAN node 1 with a first information element indicating that CA is not required or permitted for the wireless terminal 3. Conversely, if the information element from the wireless terminal 3 indicates that CA is required, the core network node 5 may provide the RAN node 1 with a first information element indicating that CA is required or permitted for the wireless terminal 3.

[0090] Furthermore, or alternatively, if an information element from the wireless terminal 3 indicates that a DC is not required, the core network node 5 may provide the RAN node 1 with a first information element indicating that a DC is not required or permitted for the wireless terminal 3. Conversely, if an information element from the wireless terminal 3 indicates that a DC is required, the core network node 5 may provide the RAN node 1 with a first information element indicating that a DC is required or permitted for the wireless terminal 3.

[0091] According to the signaling and the operation of the wireless terminal 3 and core network node 5 described in this embodiment, the wireless terminal 3 can inform the core network node 5 whether or not a CA and / or DC are required. The core network node 5 can then inform the RAN node 1 whether or not a CA and / or DC are required (or permitted) for the wireless terminal 3, taking into account the requirement of one or both of the CA and / or DC indicated by the wireless terminal 3.

[0092] <Third Embodiment> This embodiment provides an improvement to the operation of a RAN node. The configuration example of the wireless communication system according to this embodiment may be the same as the example shown in Figure 1.

[0093] Figure 15 shows an example of the operation of RAN node 1. The operation in Figure 15 may also be performed by RAN node 2 acting as the SN for the DC for wireless terminal 3. In step 1501, RAN node 1 or 2 obtains one or more maximum bitrate parameters that limit the aggregate bitrate of multiple QoS flows for wireless terminal 3. In step 1502, RAN node 1 or 2 determines, based on one or more maximum bitrate parameters, whether a CA and DC, or both, are required for wireless terminal 3.

[0094] One or more maximum bitrate parameters may include the Aggregate Maximum Bit Rate per wireless terminal, the Aggregate Maximum Bit Rate per PDU Session of wireless terminal 3, or the Maximum Bit Rate per network slice of wireless terminal 3, or any combination thereof. More specifically, one or more maximum bitrate parameters may include the per User Equipment (UE) Aggregate Maximum Bit Rate (UE-AMBR), the per Session Aggregate Maximum Bit Rate (Session-AMBR), or the per UE per Slice-Maximum Bit Rate (UE-Slice-MBR), or any combination thereof. Each of Session-AMBR, UE-AMBR, and UE-Slice-MBR includes values ​​for uplink (UL) and downlink (DL).

[0095] Session-AMBR limits the aggregate bitrate that is likely to be provided across all non-GBR QoS flows for a specific PDU session. RAN node 1 uses Session-AMBR to calculate its UE-AMBR.

[0096] UE-AMBR limits the aggregated bitrate expected to be provided across all Non-GBR QoS Flows of the wireless terminal 3 (UE). RAN node 1 enforces UE-AMBR for each UE in UL and DL for Non-GBR QoS Flows. RAN node 1 sets its UE-AMBR to the sum of the Session-AMBRs of all PDU Sessions with active user planes for the RAN (e.g., RAN nodes 1 and 2), up to the UE-AMBR received from core network 4.

[0097] The UE-Slice-MBR limits the aggregated bitrate expected to be provided across all GBR and non-GBR QoS flows corresponding to PDU sessions of a wireless terminal (UE) 3 with an active user plane within the same network slice (S-NSSAI). If RAN node 1 receives a UE-Slice-MBR for a wireless terminal (UE) 3 from core network 4 for an S-NSSAI, RAN node 1 applies this UE-Slice-MBR to all PDU sessions of the wireless terminal (UE) 3 with an active user plane corresponding to that S-NSSAI, if feasible.

[0098] RAN node 1 may receive one or more maximum bitrate parameters from core network 4 via one or more control messages.

[0099] Figure 16 is a sequence diagram showing an example of the operation of RAN node 1 and core network node 5. Core network node 5 is a control plane node included in core network 4. If core network 4 is 5GC, core network node 5 may be AMF or SMF or a combination thereof, and the signaling may be NG Application Protocol (NGAP) signaling or messages. If core network 4 is EPC, core network node 5 may be MME, and the signaling may be S1AP signaling or messages.

[0100] In step 1601, RAN node 1 (e.g., gNB or ng-eNB) receives one or more maximum bitrate parameters from core network node 5 (e.g., AMF or SMF) via one or more control messages. The one or more maximum bitrate parameters may be UE-AMBR, Session-AMBR, UE-Slice-MBR, or any combination thereof. Each of the one or more control messages may be an NGAP message. Specifically, each of the one or more control messages may be an INITIAL CONTEXT SETUP REQUEST message, a UE CONTEXT MODIFICATION REQUEST message, a PDU SESSION RESOURCE SETUP REQUEST message, or a PDU SESSION RESOURCE MODIFY REQUEST message.

[0101] In step 1602, RAN node 1 determines whether CA and DC, or both, are required for wireless terminal 3, based on one or more maximum bitrate parameters received from core network node 5.

[0102] In some implementations, the core network node 5 may provide the RAN node 1 with updated UE-AMBR, Session-AMBR, UE-Slice-MBR, or any combination thereof, depending on the communication status of the wireless terminal 3 user. Specifically, if it is detected that the wireless terminal 3 user is about to run out of data capacity that can be used or consumed within a predetermined period (e.g., 3 days, 1 week, 1 month), the core network 4 may update one or more of the UE-AMBR, Session-AMBR, and UE-Slice-MBR to decrease their values. Alternatively, if it is detected that the wireless terminal 3 user has run out of data capacity that can be used or consumed within a predetermined period (e.g., 3 days, 1 week, 1 month), the core network 4 may update one or more of the UE-AMBR, Session-AMBR, and UE-Slice-MBR to decrease their values. On the other hand, if the data capacity available to the user of wireless terminal 3 is restored due to reasons such as entering a new predetermined period, the core network 4 may update one or more of UE-AMBR, Session-AMBR, and UE-Slice-MBR to increase their values.

[0103] In some implementations, depending on other factors such as congestion in the core network 4, the core network node 5 may provide the RAN node 1 with an updated UE-AMBR, Session-AMBR, UE-Slice-MBR, or any combination thereof.

[0104] The UE-AMBR, Session-AMBR, and UE-Slice-MBR may be updated by the PCF within the core network 4. The PCF may provide the updated UE-AMBR and updated UE-Slice-MBR to the AMF and the updated Session-AMBR to the SMF.

[0105] Figure 17 is a sequence diagram showing an example of the operation of RAN nodes 1 and 2. In step 1701, RAN node 1 (e.g., gNB or ng-eNB) sends one or more maximum bitrate parameters to RAN node 2 via one or more control messages. One or more maximum bitrate parameters may be SN UE-AMBR, SN Session-AMBR, SN UE-Slice-MBR, or any combination thereof.

[0106] SN UE-AMBR, SN Session-AMBR, and SN UE-Slice-MBR are determined by RAN node 1, which acts as the MN for the DC for wireless terminal 3. Specifically, RAN node (MN) 1 separates the UE-AMBR received from core network node 5 into the UE-AMBR upper limit assigned to MN (i.e., MN UE-AMBR) and the UE-AMBR upper limit assigned to SN (i.e., SN UE-AMBR), and informs RAN node (SN) 2 of the SN UE-AMBR. Similarly, RAN node (MN) 1 separates the Session-AMBR received from core network node 5 into the Session-AMBR upper limit assigned to MN (i.e., MN Session-AMBR) and the Session-AMBR upper limit assigned to SN (i.e., SN Session-AMBR), and informs RAN node (SN) 2 of the SN Session-AMBR. Furthermore, RAN node (MN) 1 separates the UE-Slice-MBR received from core network node 5 into the UE-Slice-MBR upper limit allocated to MN (i.e., MN UE-AMBR) and the UE-Slice-MBR upper limit allocated to SN (i.e., SN UE-AMBR), and notifies RAN node (SN) 2 of the SN UE-Slice-MBR.

[0107] Each of the one or more control messages in step 1701 may be an XnAP message. Specifically, each of the one or more control messages may be an S-NODE ADDITION REQUEST message or an S-NODE MODIFICATION REQUEST message.

[0108] In step 1702, RAN node 2 determines whether CA and DC, or both, are required for wireless terminal 3, based on one or more maximum bitrate parameters received from RAN node 1.

[0109] In some implementations, if the UE-AMBR value received from the core network 4 falls below a first threshold, RAN node 1 may decide or recognize that it will not perform (or start) one or both CA and DC for the wireless terminal 3. Similarly, if the UE-AMBR falls below the first threshold, RAN node 1 may stop one or both of the CA and DC currently running for the wireless terminal 3. For example, RAN node 1 may stop using some or all of the SCell(s) or SCG(s) that are configured and activated for the wireless terminal 3. Conversely, if the UE-AMBR exceeds a second threshold, RAN node 1 may decide or recognize that it can perform (or start) one or both CA and DC for the wireless terminal 3. Similarly, if the UE-AMBR exceeds the second threshold, RAN node 1 may continue one or both of the CA and DC currently running for the wireless terminal 3. The second threshold may be the same as or different from the first threshold.

[0110] In some implementations, if the Session-AMBR value received from the core network 4 or the UE-AMBR value calculated using the Session-AMBR falls below a first threshold, RAN node 1 may decide or recognize that it will not perform (or start) one or both CA and DC for wireless terminal 3. Similarly, if the Session-AMBR or UE-AMBR falls below the first threshold, RAN node 1 may stop one or both of the CA and DC currently running for wireless terminal 3. For example, RAN node 1 may stop using some or all of the SCell(s) or SCG(s) that are set up and activated for the QoS Flow(s) of the PDU Session associated with the Session-AMBR that falls below the first threshold. Conversely, if the Session-AMBR or UE-AMBR exceeds a second threshold, RAN node 1 may decide or recognize that it can perform (or start) one or both CA and DC for wireless terminal 3. Similarly, if the Session-AMBR or UE-AMBR exceeds the second threshold, RAN node 1 may continue one or both of the CA and DC running for wireless terminal 3. The second threshold may be the same as or different from the first threshold.

[0111] In some implementations, RAN node 1 may decide or recognize that if the UE-Slice-MBR received from core network 4 falls below a first threshold, RAN node 1 will not perform (or start) one or both CA and DC for wireless terminal 3. Similarly, if the UE-Slice-MBR falls below the first threshold, RAN node 1 may stop one or both of the CA and DC currently running for wireless terminal 3. For example, RAN node 1 may stop using some or all of the SCell(s) or SCG(s) that are configured and activated for QoS Flow(s) of PDU Session(s) with active user planes in the network slice associated with the UE-Slice-MBR that falls below the first threshold. Conversely, if the UE-Slice-MBR exceeds a second threshold, RAN node 1 may decide or recognize that it can perform (or start) one or both CA and DC for wireless terminal 3. Similarly, if the UE-Slice-MBR exceeds the second threshold, RAN node 1 may continue one or both of the CA and DC being performed for wireless terminal 3. The second threshold may be the same as or different from the first threshold.

[0112] Similar to the operation of RAN node 1, RAN node 2 may use the SN UE-AMBR, SN Session-AMBR, or SN UE-Slice-MBR received from RAN node 1 to determine whether to perform, start, stop, or continue CA and DC, or both, for the radio terminal 3.

[0113] CA may be initiated by adding or configuring one or more SCells, or by activating one or more SCells that have already been added or configured. SCell(s) may be added or released by RAN node 1 or 2 sending an RRC (Connection) Reconfiguration message to wireless terminal 3. SCell(s) may be activated by RAN node 1 or 2 sending an SCell Activation / Deactivation MAC CE to wireless terminal 3.

[0114] CA deactivation may be performed by releasing one or more SCells, or by deactivating one or more SCells. SCells may be released by RAN node 1 or 2 sending an RRC (Connection) Reconfiguration message to radio terminal 3. SCells may be deactivated by RAN node 1 or 2 sending a SCell Activation / Deactivation MAC CE to radio terminal 3. RAN node 1 or 2 may provide radio terminal 3 with updated measurement settings via the RRC (Connection) Reconfiguration message so as to exclude the frequencies of the released SCell(s) from the measurement target of radio terminal 3.

[0115] DC activation may be performed by adding or configuring a new SN and SCG, or by activating an added or configured SCG. Adding an SN and SCG may be performed by MN (e.g., RAN node 1) initiating the SN Addition procedure. This SN Addition procedure includes sending an S-NODE ADDITION REQUEST message from MN (e.g., RAN node 1) to SN (e.g., RAN node 2). This SN Addition procedure further includes sending an MN RRC Reconfiguration message from RAN node 1 to wireless terminal 3, which includes an SN RRC configuration message generated by RAN node 2. SCG activation may be performed by sending an RRC message, MAC CE, or Downlink Control Information (DCI) from MN (e.g., RAN node 1) or SN (e.g., RAN node 2) to wireless terminal 3.

[0116] The DC may be shut down by releasing the SN and SCG, or by deactivating the SCG. Releasing the SN and SCG may be done by the MN (e.g., RAN node 1) or SN (e.g., RAN node 2) initiating an SN Release procedure. An SN Release procedure initiated by the MN includes sending an S-NODE RELEASE REQUEST message from the MN (e.g., RAN node 1) to the SN (e.g., RAN node 2). An SN Release procedure initiated by the SN includes sending an S-NODE RELEASE REQUIRED message from the SN (e.g., RAN node 2) to the MN (e.g., RAN node 1). In these SN Release procedures, the MN (e.g., RAN node 1) may, if necessary, indicate to the wireless terminal 3 with an MN RRC Reconfiguration message that the wireless terminal 3 should release all SCG settings. MN (e.g., RAN node 1) may provide the wireless terminal 3 with updated measurement settings via an RRC (Connection) Reconfiguration message so as to exclude the freed SCG frequencies from the measurement targets of the wireless terminal 3.

[0117] In an SN Release procedure initiated by an MN (e.g., RAN node 1), the MN may include a Cause information element indicating the reason for SN release in the S-NODE RELEASE REQUEST message. Similarly, in an SN Release procedure initiated by an SN (e.g., RAN node 2), the SN may include a Cause information element indicating the reason for SN release in the S-NODE RELEASE REQUIRED message. This Cause information element may be set to a value that, for example, indicates that wireless terminal 3 is about to use up its contracted data allowance, or that wireless terminal 3 has used up its contracted data allowance. As an example, this Cause information element may be set to "UE Available Data Reaches Maximum".

[0118] According to the operation of RAN node 1 as described with reference to Figures 15 and 16, RAN node 1 can determine whether CA or DC is necessary for wireless terminal 3 using the maximum bitrate parameters (e.g., UE-AMBR, Session-AMBR, UE-Slice-MBR, or any combination thereof) provided by the core network 4 for wireless terminal 3. For example, RAN node 1 may shut down DC for some or all of one or more PDU sessions of wireless terminal 3 in response to a decrease in UE-AMBR, Session-AMBR, or UE-Slice-MBR for wireless terminal 3. This can, for example, help to reduce the wasteful consumption of RAN's computing and wireless resources.

[0119] According to the operation of RAN node 2 as described with reference to Figures 15 and 17, RAN node 2 can determine whether CA or DC is necessary for wireless terminal 3 using the maximum bitrate parameters for wireless terminal 3 provided by RAN node 1 (e.g., SN UE-AMBR, SN Session-AMBR, SN UE-Slice-MBR, or any combination thereof). For example, RAN node 2 may stop DC for some or all of one or more PDU sessions of wireless terminal 3 in response to a decrease in UE-AMBR, Session-AMBR, or UE-Slice-MBR for wireless terminal 3. This can, for example, help to reduce the wasteful consumption of RAN's computing and wireless resources.

[0120] Figures 18 to 23 provide specific examples of the operation of RAN nodes 1 and 2. The following explanation will describe examples of the operation of RAN nodes 1 and 2 with reference to these figures.

[0121] Figure 18 shows an example of the operation of RAN node 1 or 2. Step 1801 is similar to step 1501 in Figure 15.

[0122] In step 1802, RAN node 1 or 2 decides whether to perform (or initiate) one or both CA and DC for wireless terminal 3, based on one or more maximum bitrate parameters. In other words, RAN node 1 or 2 decides whether to perform (or initiate) one or both CA and DC for wireless terminal 3, based on or relying on one or more maximum bitrate parameters, or using or considering such information. The method of this decision has already been explained, so a redundant explanation will be omitted here.

[0123] Figure 19 shows an example of the operation of RAN node 1 or 2. Step 1901 is similar to step 1501 in Figure 15.

[0124] In step 1902, RAN node 1 or 2 determines the number of SCells to be set up or activated in the CA for wireless terminal 3 based on one or more maximum bitrate parameters. RAN node 1 or 2 may increase the number of SCells set up or activated as the value of the maximum bitrate parameter increases. In other words, RAN node 1 or 2 may decrease the number of SCells set up or activated as the value of the maximum bitrate parameter decreases.

[0125] Figure 20 shows an example of the operation of RAN node 1 or 2. Step 2001 is similar to step 1501 in Figure 15, except that in step 2001, while RAN node 1 or 2 is performing CA for wireless terminal 3, RAN node 1 or 2 obtains one or more maximum bitrate parameters for wireless terminal 3.

[0126] In step 2002, RAN node 1 or 2 decides, based on one or more maximum bitrate parameters, whether to stop using some or all of the SCells of the CA currently running for the wireless terminal 3. The method of this decision may be the same as any of the methods already described. Multiple thresholds may be used for this decision. Specifically, if the value of the maximum bitrate parameter is below a first threshold, RAN node 1 or 2 may release (or deactivate) some of the SCells set (or activated) in the CA. If the value of the maximum bitrate parameter is below a second threshold that is smaller than the first threshold, RAN node 1 or 2 may release (or deactivate) all of the SCells set (or activated) in the CA.

[0127] Figure 21 shows an example of the operation of RAN node 1 or 2. Step 2101 is similar to step 1501 in Figure 15, except that in step 2101, while RAN nodes 1 and 2 are performing DC for wireless terminal 3, RAN node 1 or 2 obtains one or more maximum bitrate parameters for wireless terminal 3.

[0128] In step 2102, RAN node 1 or 2 decides, based on one or more maximum bitrate parameters, whether to stop using some or all of the SCGs of one or more DCs running for the wireless terminal 3. The method of this decision may be the same as any of the methods already described. Multiple thresholds may be used for this decision. Specifically, if the value of the maximum bitrate parameter is below a first threshold, RAN node 1 or 2 may release (or deactivate) some of the SCGs set (or activated) in the DC. If the value of the maximum bitrate parameter is below a second threshold which is smaller than the first threshold, RAN node 1 or 2 may release (or deactivate) all of the SCGs set (or activated) in the DC.

[0129] Figure 22 shows an example of the operation of RAN node 1. Step 2201 is similar to step 1501 in Figure 15.

[0130] In step 2202, if the value of the maximum bitrate parameter is below a first threshold, RAN node 1 determines or recognizes that DC is not required for the wireless terminal 3. In step 2203, if the value of the maximum bitrate parameter is below a second threshold which is smaller than the first threshold, RAN node 1 determines or recognizes that neither DC nor CA is required for the wireless terminal 3. The order of steps 2202 and 2203 is not limited. Steps 2202 and 2203 may be performed substantially simultaneously, or step 2203 may be performed before step 2202.

[0131] Figure 23 shows an example of the operation of RAN node 1. Step 2301 is similar to step 1501 in Figure 15, except that in step 2301, while RAN node 1 is performing one or both CA and DC for wireless terminal 3, RAN node 1 obtains the maximum bitrate parameter.

[0132] In step 2302, if the value of the maximum bitrate parameter falls below the first threshold, RAN node 1 stops either or both CA and DC for wireless terminal 3.

[0133] In step 2303, RAN node 1 does not initiate either or both CA and DC for wireless terminal 3 until the value of the maximum bitrate parameter exceeds a second threshold greater than the first threshold. In other words, RAN node 2 stops either or both CA and DC for wireless terminal 3 until it obtains an updated value of the maximum bitrate parameter that exceeds the second threshold.

[0134] <Fourth Embodiment> This embodiment provides an improvement to the operation of a RAN node. The configuration example of the wireless communication system according to this embodiment may be the same as the example shown in Figure 1.

[0135] Figure 24 shows an example of the operation of RAN node 1. In step 2401, RAN node 1 obtains one or more maximum bitrate parameters that limit the aggregate bitrate of multiple QoS flows for the wireless terminal 3. Specific examples of one or more maximum bitrate parameters may be similar to those described in the third embodiment. Specifically, one or more maximum bitrate parameters may be UE-AMBR, Session-AMBR, or UE-Slice-MBR, or any combination thereof. RAN node 1 may receive one or more maximum bitrate parameters from the core network 4 via one or more control messages.

[0136] In step 2402, RAN node 1 determines whether to hand over the wireless terminal 3 from its current serving cell to another cell based on one or more maximum bitrate parameters. For example, if the value of the maximum bitrate parameter is below a first threshold, RAN node 1 may decide to hand over the wireless terminal 3 from its current high-speed serving cell to another cell. Conversely, if the value of the maximum bitrate parameter exceeds a second threshold, RAN node 1 may decide to hand over the wireless terminal 3 from its current serving cell to another high-speed cell. The second threshold may be the same as or different from the first threshold. For example, the high-speed cell may be a cell operating in the mmWave (FR2) band, and the other cell may be a cell operating in the sub-6 GHz (FR1) band. Alternatively, the high-speed cell may be a 5G New Radio (NR) cell, and the other cell may be an LTE cell.

[0137] According to the operation of RAN node 1 as described with reference to Figure 24, RAN node 1 can determine whether a handover of wireless terminal 3 is necessary using the maximum bitrate parameters (e.g., UE-AMBR, Session-AMBR, UE-Slice-MBR, or any combination thereof) provided by the core network 4 for wireless terminal 3.

[0138] Next, configuration examples of RAN nodes 1 and 2, wireless terminal 3, and core network node 5 according to the above-described multiple embodiments will be explained. Figure 25 is a block diagram showing a configuration example of RAN node 1. The configuration of the other RAN node 2 may be the same as the configuration shown in Figure 25. Referring to Figure 25, RAN node 1 includes a radio frequency transceiver 2501, a network interface 2503, a processor 2504, and a memory 2505. The RF transceiver 2501 performs analog RF signal processing to communicate with UEs, including UE3. The RF transceiver 2501 may include multiple transceivers. The RF transceiver 2501 is coupled with an antenna array 2502 and a processor 2504. The RF transceiver 2501 receives modulation symbol data from the processor 2504, generates a transmit RF signal, and supplies the transmit RF signal to the antenna array 2502. Furthermore, the RF transceiver 2501 generates a baseband received signal based on the received RF signal received by the antenna array 2502 and supplies it to the processor 2504. The RF transceiver 2501 may also include an analog beamformer circuit for beamforming. The analog beamformer circuit may include, for example, multiple phase shifters and multiple power amplifiers.

[0139] Network interface 2503 is used to communicate with network nodes (e.g., other RAN nodes, and nodes within core network 4). Network interface 2503 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0140] Processor 2504 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Processor 2504 may include multiple processors. For example, processor 2504 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.

[0141] For example, the digital baseband signal processing by processor 2504 may include signal processing for the Service Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and Physical (PHY) layer. Furthermore, the control plane processing by processor 2504 may include processing of Non-Access Stratum (NAS) messages, RRC messages, MAC Control Elements (CEs), and Downlink Control Information (DCI).

[0142] The processor 2504 may include a digital beamformer module for beamforming. The digital beamformer module may include a Multiple Input Multiple Output (MIMO) encoder and precoder.

[0143] Memory 2505 is comprised of a combination of volatile and non-volatile memory. Volatile memory may be, for example, Static Random Access Memory (SRAM) or Dynamic RAM (DRAM), or a combination thereof. Non-volatile memory may be Mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. Memory 2505 may also include storage located away from the processor 2504. In this case, the processor 2504 may access memory 2505 via the network interface 2503 or an I / O interface not shown.

[0144] The memory 2505 may store one or more software modules (computer programs) 2506 containing instruction sets and data for processing by the RAN node 1 as described in the above embodiments. In some implementations, the processor 2504 may be configured to read the software modules 2506 from the memory 2505 and execute them to perform the processing of the RAN node 1 as described in the above embodiments.

[0145] The control plane processing and operations performed by the RAN node 1 described in the above embodiment can be realized by the processor 2504 and the memory 2505 which stores the software module 2506.

[0146] If RAN node 1 is a CU (e.g., eNB-CU or gNB-CU) or CU-CP, RAN node 1 does not need to include RF transceiver 2501 (and antenna array 2502).

[0147] Figure 26 is a block diagram showing an example configuration of wireless terminal 3. The Radio Frequency (RF) transceiver 2601 performs analog RF signal processing to communicate with RAN nodes 1 and 2. The RF transceiver 2601 may include multiple transceivers. The analog RF signal processing performed by the RF transceiver 2601 includes frequency up-conversion, frequency down-conversion, and amplification. The RF transceiver 2601 is coupled with the antenna array 2602 and the baseband processor 2603. The RF transceiver 2601 receives modulation symbol data (or OFDM symbol data) from the baseband processor 2603, generates a transmit RF signal, and supplies the transmit RF signal to the antenna array 2602. The RF transceiver 2601 also generates a baseband receive signal based on the received RF signal received by the antenna array 2602 and supplies this to the baseband processor 2603. The RF transceiver 2601 may include an analog beamformer circuit for beamforming. The analog beamformer circuit includes, for example, multiple phase shifters and multiple power amplifiers.

[0148] The baseband processor 2603 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 path coding / decoding, (e) modulation (symbol mapping) / demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) by Inverse Fast Fourier Transform (IFFT). Control plane processing, on the other hand, includes communication management at Layer 1 (e.g., transmit power control), Layer 2 (e.g., radio resource management and hybrid automatic repeat request (HARQ) processing), and Layer 3 (e.g., signaling related to attach, mobility, and call management).

[0149] For example, the digital baseband signal processing by the baseband processor 2603 may include signal processing for the SDAP layer, PDCP layer, RLC layer, MAC layer, and PHY layer. Furthermore, the control plane processing by the baseband processor 2603 may include processing for the Non-Access Stratum (NAS) protocol, RRC protocol, MAC CEs, and DCIs.

[0150] The baseband processor 2603 may perform MIMO encoding and precoding for beamforming.

[0151] The baseband processor 2603 may include a modem processor (e.g., DSP) for performing digital baseband signal processing and a protocol stack processor (e.g., CPU or MPU) for performing control plane processing. In this case, the protocol stack processor for performing control plane processing may be shared with the application processor 2604 described later.

[0152] The application processor 2604 is also called a CPU, MPU, microprocessor, or processor core. The application processor 2604 may include multiple processors (multiple processor cores). The application processor 2604 implements various functions of the wireless terminal 3 by executing system software programs (Operating System (OS)) and various application programs (e.g., calling applications, web browsers, mail clients, camera operation applications, music playback applications) read from memory 2606 or memory not shown.

[0153] In some implementations, the baseband processor 2603 and the application processor 2604 may be integrated on a single chip, as shown by the dashed line (2605) in Figure 26. In other words, the baseband processor 2603 and the application processor 2604 may be implemented as a single System on Chip (SoC) device 2605. An SoC device is sometimes called a System Large Scale Integration (LSI) or chipset.

[0154] Memory 2606 is volatile memory, non-volatile memory, or a combination thereof. Memory 2606 may include multiple physically independent memory devices. Volatile memory is, for example, SRAM or DRAM, or a combination thereof. Non-volatile memory is MROM, EEPROM, flash memory, or hard disk drive, or any combination thereof. For example, memory 2606 may include an external memory device accessible from the baseband processor 2603, the application processor 2604, and the SoC 2605. Memory 2606 may also include an internal memory device integrated within the baseband processor 2603, the application processor 2604, or the SoC 2605. Furthermore, memory 2606 may include memory within a Universal Integrated Circuit Card (UICC).

[0155] The memory 2606 may store one or more software modules (computer programs) 2607 containing instruction sets and data for processing by the wireless terminal 3 as described in the above-described embodiments. In some implementations, the baseband processor 2603 or application processor 2604 may be configured to read and execute the software modules 2607 from the memory 2606 to perform the processing of the wireless terminal 3 as described with reference to the drawings in the above embodiments.

[0156] The control plane processing and operations performed by the wireless terminal 3 described in the above-described embodiment can be realized by elements other than the RF transceiver 2601 and antenna array 2602, namely at least one of the baseband processor 2603 and application processor 2604 and the memory 2606 storing the software module 2607.

[0157] Figure 27 shows an example configuration of core network node 5. Referring to Figure 27, core network node 5 includes a network interface 2701, a processor 2702, and memory 2703.

[0158] The network interface 2701 is used, for example, to communicate with other network functions (NFs) or nodes. The network interface 2701 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0159] The processor 2702 may be, for example, a microprocessor, an MPU, or a CPU. The processor 2702 may include multiple processors.

[0160] Memory 2703 is composed of volatile memory and non-volatile memory. Memory 2703 may include multiple physically independent memory devices. Volatile memory is, for example, SRAM or DRAM or a combination thereof. Non-volatile memory is MROM, EEPROM, flash memory, or hard disk drive, or any combination thereof. Memory 2703 may include storage located away from the processor 2702. In this case, the processor 2702 may access memory 2703 via a network interface 2701 or an I / O interface.

[0161] The memory 2703 may store one or more software modules (computer programs) 2704 containing instruction sets and data for processing by the core network node 5 as described in the above embodiments. In some implementations, the processor 2702 may be configured to read and execute the software modules 2704 from the memory 2703 to perform the processing of the core network node 5 as described in the above embodiments.

[0162] As illustrated with reference to Figures 25, 26, and 27, each of the processors in the RAN nodes 1 and 2, the wireless terminal 3, and the core network node 5 according to the above embodiment can execute one or more programs containing a set of instructions for causing a computer to perform the algorithms described with reference to the drawings. The program, when loaded into a computer, contains a set of instructions (or software code) for causing the computer to perform one or more of the functions described in the embodiment. The program may be stored on a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited to, include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD), or other memory technologies, CD-ROM, digital versatile disk (DVD), Blu-ray® disc, or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage, or other magnetic storage devices. The program may be transmitted over a temporary computer-readable medium or a communication medium. As an example, and not an limitation, temporary computer-readable or communication media include propagating signals of electrical, optical, acoustic, or other forms.

[0163] Furthermore, the embodiments described above are merely examples of how the technical concept obtained by the present inventor can be applied. In other words, the technical concept is not limited to the embodiments described above, and various modifications are certainly possible.

[0164] For example, some or all of the above embodiments may also be described as follows, but are not limited to the following.

[0165] (Note 1) At least one memory, The system includes at least one processor coupled to the aforementioned memory and configured to receive a first control message from the core network that includes a first information element relating to a wireless terminal, Equipped with, The first information element mentioned above is, · The amount of data that the wireless terminal can use; or Whether carrier aggregation and / or dual connectivity are required or permitted for the wireless terminal. A wireless access network node that represents at least one of the following. (Note 2) The first information element indicates at least whether carrier aggregation and / or dual connectivity are required or permitted for the wireless terminal. The wireless access network node described in Appendix 1. (Note 3) The first information element indicates at least the amount of data available to the wireless terminal, The amount of data mentioned above is the remaining amount of data available to the user of the wireless terminal by the end of the month. The wireless access network node described in Appendix 1. (Note 4) The at least one processor is configured to determine, based on the first information element, whether to perform carrier aggregation and / or dual connectivity for the wireless terminal. A wireless access network node as described in any one of the following appendices 1 to 3. (Note 5) The at least one processor is configured to determine, based on the first information element, whether to stop using some or all of the secondary cells of one or more carrier aggregations running for the wireless terminal. A wireless access network node as described in any one of the following appendices 1 to 3. (Note 6) The at least one processor is configured to determine, based on the first information element, whether to stop using some or all of the secondary cell groups of one or more dual connectivity running for the wireless terminal. A wireless access network node as described in any one of the following appendices 1 to 3. (Note 7) The at least one processor is configured to transmit a second control message, which includes a second information element derived based on the first information element, to a secondary node of dual connectivity for the wireless terminal. A wireless access network node as described in any one of the following appendices 1 to 3. (Note 8) The second information element is used by the secondary node to determine whether to stop using some or all of the secondary cells of one or more carrier aggregations running in the secondary cell group for the wireless terminal. The wireless access network node described in Appendix 7. (Note 9) The second information element is used by the secondary node to determine whether to discontinue the use of some or all of the secondary cell groups of the dual connectivity running for the wireless terminal. The wireless access network node described in Appendix 7. (Note 10) The at least one processor is configured to determine, based on the first information element, whether or not to hand over the wireless terminal from the current serving cell to another cell. A wireless access network node as described in any one of the following appendices 1 to 3. (Note 11) The at least one processor is configured to recognize that dual connectivity is not required for the wireless terminal if the amount of data falls below a first threshold, and The at least one processor is configured to recognize that neither dual connectivity nor carrier aggregation is required for the wireless terminal if the amount of data falls below a second threshold which is smaller than the first threshold. A wireless access network node as described in Appendix 1 or 3. (Note 12) The at least one processor is configured to stop either or both carrier aggregation and dual connectivity for the wireless terminal if the amount of data falls below a third threshold. The at least one processor is configured not to initiate carrier aggregation and / or dual connectivity for the wireless terminal until the amount of data exceeds a fourth value greater than the third threshold. A wireless access network node as described in any one of the following appendices: 1, 3, and 11. (Note 13) The first control message is an NG Application Protocol (NGAP) message, The first control message is an INITIAL CONTEXT SETUP REQUEST message, a UE CONTEXT MODIFICATION REQUEST message, or a PDU SESSION RESOURCE SETUP REQUEST message. A wireless access network node as described in any one of the appendices 1 to 12. (Note 14) The second control message is an Xn Application Protocol (XnAP) message, The second control message is either an S-NODE ADDITION REQUEST message or an S-NODE MODIFICATION REQUEST message. A wireless access network node as described in any one of the items 7 to 9 of the appendix. (Note 15) The system includes receiving a first control message from the core network that contains a first information element relating to a wireless terminal, The first information element mentioned above is, · The amount of data that the wireless terminal can use; or Whether carrier aggregation and / or dual connectivity are required or permitted for the wireless terminal. Show at least one of the following: A method performed by a wireless access network node. (Note 16) A program that causes a computer to perform a method for a wireless access network node, The method comprises receiving a first control message from a core network that includes a first information element relating to a wireless terminal, The first information element mentioned above is, · The amount of data that the wireless terminal can use; or Whether carrier aggregation and / or dual connectivity are required or permitted for the wireless terminal. A program that demonstrates at least one of the following. (Note 17) At least one memory, The system includes at least one processor coupled to the at least one memory and configured to transmit a first control message containing a first information element relating to a wireless terminal to a wireless access network node, Equipped with, The first information element mentioned above is, · The amount of data that the wireless terminal can use; or Whether carrier aggregation and / or dual connectivity are required or permitted for the wireless terminal. A core network node that represents at least one of the following. (Note 18) The first information element indicates at least whether carrier aggregation and / or dual connectivity are required or permitted for the wireless terminal. The core network node described in Appendix 17. (Note 19) The first information element indicates at least the amount of data available to the wireless terminal, The amount of data mentioned above is the remaining amount of data available to the user of the wireless terminal by the end of the month. The core network node described in Appendix 17. (Note 20) The first information element is used by the radio access network node to determine whether to perform carrier aggregation and / or dual connectivity for the radio terminal. A core network node as described in any one of the items 17-19 of the appendix. (Note 21) The first information element is used by the wireless access network node to determine whether to discontinue the use of some or all of the secondary cells of one or more carrier aggregations running for the wireless terminal. A core network node as described in any one of the items 17-19 of the appendix. (Note 22) The first information element is used by the wireless access network node to stop the use of some or all of the secondary cell groups of the dual connectivity running for the wireless terminal. A core network node as described in any one of the items 17-19 of the appendix. (Note 23) The first information element is used by the radio access network node to determine whether or not to hand over the radio terminal from the current serving cell to another cell. A core network node as described in any one of the items 17-19 of the appendix. (Note 24) The at least one processor is configured to receive a second control message from the wireless terminal that includes an information element indicating whether carrier aggregation and / or dual connectivity are required. The at least one processor is configured to determine the first information element based on the information element received from the wireless terminal. A core network node as described in any one of the items 17-23 in the appendix. (Note 25) The first control message is an NG Application Protocol (NGAP) message, The first control message is an INITIAL CONTEXT SETUP REQUEST message, a UE CONTEXT MODIFICATION REQUEST message, or a PDU SESSION RESOURCE SETUP REQUEST message. A core network node as described in any one of the items 17-24 of the appendix. (Note 26) The system includes transmitting a first control message containing a first information element relating to a wireless terminal to a wireless access network node. The first information element mentioned above is, · The amount of data that the wireless terminal can use; or Whether carrier aggregation and / or dual connectivity are required or permitted for the wireless terminal. Show at least one of the following: A method performed by core network nodes. (Note 27) A program that causes a computer to perform a method for core network nodes, The method comprises transmitting a first control message containing a first information element relating to a wireless terminal to a wireless access network node. The first information element mentioned above is, · The amount of data that the wireless terminal can use; or Whether carrier aggregation and / or dual connectivity are required or permitted for the wireless terminal. A program that demonstrates at least one of the following. (Note 28) At least one memory, At least one processor coupled to the aforementioned at least one memory and configured to send a control message to the core network containing an information element indicating whether carrier aggregation and / or dual connectivity are required, Equipped with, Wireless terminal. (Note 29) The information element is used by the core network to inform the radio access network node whether carrier aggregation and / or dual connectivity are required or permitted for the radio terminal. The wireless terminal described in Appendix 28. (Note 30) The aforementioned control message is a Non-Access-Stratum (NAS) message, The control message is a REGISTRATION REQUEST message, a SERVICE REQUEST message, a UL NAS TRANSPORT message, a PDU SESSION ESTABLISHMENT REQUEST message, or a PDU SESSION MODIFICATION REQUEST message. Wireless terminals as described in Appendix 28 or 29. (Note 31) The system includes sending a control message to the core network that contains informational elements indicating whether carrier aggregation and / or dual connectivity are required. A method performed using wireless terminals. (Note 32) A method for causing a computer to perform a method for a wireless terminal, comprising transmitting a control message to a core network containing an informational element indicating whether carrier aggregation and / or dual connectivity are required. (Note 33) At least one memory, At least one processor coupled to the at least one memory, Equipped with, The aforementioned at least one processor is Obtain one or more maximum bitrate parameters that limit the aggregate bitrate of multiple Quality of Service (QoS) flows related to wireless terminals. Based on the one or more maximum bitrate parameters, it is determined whether carrier aggregation and / or dual connectivity are required for the wireless terminal. A wireless access network node configured in such a way. (Note 34) The decision includes determining whether to perform dual connectivity for the wireless terminal based on the one or more maximum bitrate parameters. The wireless access network node described in Appendix 33. (Note 35) The decision includes determining whether to perform carrier aggregation for the wireless terminal based on the one or more maximum bitrate parameters. The wireless access network node described in Appendix 33. (Note 36) The determination includes determining the number of secondary cells to be set up or activated in carrier aggregation for the wireless terminal based on the one or more maximum bitrate parameters. The wireless access network node described in Appendix 33. (Note 37) The decision includes determining whether to discontinue the use of some or all of the secondary cells of one or more carrier aggregations running for the wireless terminal, based on the one or more maximum bitrate parameters. The wireless access network node described in Appendix 33. (Note 38) The decision includes determining whether to discontinue the use of some or all of the one or more secondary cell groups of dual connectivity running for the wireless terminal, based on the one or more maximum bitrate parameters. The wireless access network node described in Appendix 33. (Note 39) The at least one processor is configured to recognize that dual connectivity is not required for the wireless terminal if one of the one or more maximum bitrate parameters falls below a first threshold, and The at least one processor is configured to recognize that neither dual connectivity nor carrier aggregation is required for the wireless terminal if the one maximum bitrate parameter falls below a second threshold which is smaller than the first threshold. The wireless access network node described in Appendix 33. (Note 40) The at least one processor is configured to stop either or both carrier aggregation and dual connectivity for the wireless terminal if one of the one or more maximum bitrate parameters falls below a third threshold. The at least one processor is configured not to initiate either or both carrier aggregation and dual connectivity for the wireless terminal until the one maximum bitrate parameter exceeds a fourth value greater than the third threshold. The wireless access network node described in Appendix 33. (Note 41) The one or more maximum bitrate parameters include the Aggregate Maximum Bit Rate for each wireless terminal, the Aggregate Maximum Bit Rate for each PDU Session of the wireless terminal, or the Maximum Bit Rate for each network slice of the wireless terminal, or any combination thereof. A wireless access network node as described in any one of the items 33 to 40 of the appendix. (Note 42) The aforementioned one or more maximum bitrate parameters include per User Equipment Aggregate Maximum Bit Rate (UE-AMBR), per Session Aggregate Maximum Bit Rate (Session-AMBR), or per UE per Slice-Maximum Bit Rate (UE-Slice-MBR), or any combination thereof. A wireless access network node as described in any one of the items 33 to 40 of the appendix. (Note 43) The acquisition of the one or more maximum bitrate parameters includes receiving the one or more maximum bitrate parameters from the core network via one or more control messages. A wireless access network node as described in any one of the items in Appendix 33 to 42. (Note 44) Each of the one or more control messages is an NG Application Protocol (NGAP) message. Each of the one or more control messages is an INITIAL CONTEXT SETUP REQUEST message, a UE CONTEXT MODIFICATION REQUEST message, a PDU SESSION RESOURCE SETUP REQUEST message, or a PDU SESSION RESOURCE MODIFY REQUEST message. The wireless access network node described in Appendix 43. (Note 45) The acquisition of the one or more maximum bitrate parameters includes receiving the one or more maximum bitrate parameters from the dual connectivity master node via one or more control messages. A wireless access network node as described in any one of the appendices 33, 35-38, and 40. (Note 46) The aforementioned control message is an Xn Application Protocol (XnAP) message, The control message is either an S-NODE ADDITION REQUEST message or an S-NODE MODIFICATION REQUEST message. The wireless access network node described in Appendix 45. (Note 47) Obtaining one or more maximum bitrate parameters that limit the aggregate bitrate of multiple Quality of Service (QoS) flows related to wireless terminals, and Based on the one or more maximum bitrate parameters, determine whether carrier aggregation and / or dual connectivity are required for the wireless terminal. A method performed by a wireless access network node, comprising the above. (Note 48) A program for causing a computer to perform a method for a wireless access network node, The aforementioned method, Obtaining one or more maximum bitrate parameters that limit the aggregate bitrate of multiple Quality of Service (QoS) flows related to wireless terminals, and Based on the one or more maximum bitrate parameters, determine whether carrier aggregation and / or dual connectivity are required for the wireless terminal. A program that includes the following features. (Note 49) At least one memory, At least one processor coupled to the at least one memory, Equipped with, The aforementioned at least one processor is Obtain one or more maximum bitrate parameters that limit the aggregate bitrate of multiple Quality of Service (QoS) flows related to wireless terminals. Based on the aforementioned one or more maximum bitrate parameters, it is determined whether or not to hand over the wireless terminal from the current serving cell to another cell. A wireless access network node configured in such a way. (Note 50) The one or more maximum bitrate parameters include the Aggregate Maximum Bit Rate for each wireless terminal, the Aggregate Maximum Bit Rate for each PDU Session of the wireless terminal, or the Maximum Bit Rate for each network slice of the wireless terminal, or any combination thereof. The wireless access network node described in Appendix 49. (Note 51) The acquisition of the one or more maximum bitrate parameters includes receiving the one or more maximum bitrate parameters from the core network via one or more control messages. A wireless access network node as described in Appendix 49 or 50. (Note 52) Obtaining one or more maximum bitrate parameters that limit the aggregate bitrate of multiple Quality of Service (QoS) flows related to wireless terminals, and Based on the aforementioned one or more maximum bitrate parameters, determine whether or not to hand over the wireless terminal from the current serving cell to another cell. A method performed by a wireless access network node, comprising the above. (Note 53) A program for causing a computer to perform a method for a wireless access network node, The aforementioned method, Obtaining one or more maximum bitrate parameters that limit the aggregate bitrate of multiple Quality of Service (QoS) flows related to wireless terminals, and Based on the aforementioned one or more maximum bitrate parameters, determine whether or not to hand over the wireless terminal from the current serving cell to another cell. A program that includes the following features.

[0166] This application claims priority based on Japanese Patent Application No. 2022-090224, filed on 2 June 2022, and incorporates all of its disclosures herein. [Explanation of Symbols]

[0167] 1 RANNode 2 RANNodes 3 Wireless terminals 4 Core Network 5 Core Network Nodes 2504 Processor 2505 memory 2506 modules 2603 Baseband Processor 2604 Application Processor 2606 memory 2607 modules 2702 Processor 2703 memory 2704 modules

Claims

1. The wireless terminal includes means for receiving a first control message from a core network that includes a first information element indicating at least the remaining amount of data available for use over a predetermined period. Wireless access network node.

2. The system further comprises means for determining, based on the first information element, whether to perform carrier aggregation and / or dual connectivity for the wireless terminal. A wireless access network node according to claim 1.

3. The system further comprises means for determining, based on the first information element, whether or not to discontinue the use of some or all of the secondary cells of one or more carrier aggregations running for the wireless terminal. A wireless access network node according to claim 1.

4. The system further comprises means for determining, based on the first information element, whether to discontinue the use of some or all of the secondary cell groups of the dual connectivity running for the wireless terminal, A wireless access network node according to claim 1.

5. The system further comprises means for transmitting a second control message, which includes a second information element derived based on the first information element, to a secondary node of dual connectivity for the wireless terminal. A wireless access network node according to claim 1.

6. If the remaining amount of the aforementioned data falls below a first threshold, means for recognizing that dual connectivity is not required for the wireless terminal, The system includes means for recognizing that neither dual connectivity nor carrier aggregation is required for the wireless terminal if the remaining amount of data falls below a second threshold which is smaller than the first threshold. A wireless access network node according to claim 1.

7. The wireless terminal receives a first control message from the core network that includes a first information element indicating at least the remaining amount of data available for use over a predetermined period. A method performed by a wireless access network node.

8. A program that causes a computer to perform a method for a wireless access network node, The method comprises receiving a first control message from a core network that includes at least a first information element indicating the remaining amount of data available to the wireless terminal for a predetermined period. program.

9. The wireless terminal includes means for transmitting a first control message to a wireless access network node, which includes a first information element indicating at least the remaining amount of data available for use over a predetermined period. Core network node.

10. The system includes means for transmitting a control message to the core network that contains informational elements indicating whether carrier aggregation and / or dual connectivity are required. Wireless terminal.

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