Wireless base station, wireless communication system, and wireless communication method

Abstract

This wireless base station receives, from a terminal, a deactivation display of a secondary cell group. Upon reception of the deactivation display, the wireless base station transmits, to a secondary node, a message that includes the deactivation display of the secondary cell group.

Description

Radio base station, radio communication system, and radio communication method

[0001] The present invention relates to a radio base station, a radio communication system, and a radio communication method that support activation and deactivation of secondary cell groups.

[0002] The 3rd Generation Partnership Project (3GPP) is developing specifications for the 5th generation mobile communication system (5G, also known as New Radio (NR) or Next Generation (NG)), and is also developing specifications for the next generation, known as Beyond 5G, 5G Evolution, or 6G.

[0003] For example, in 3GPP Release-17, an extension of Multi-RAT Dual Connectivity (MR-DC) is being considered (Non-Patent Document 1). Specifically, support for efficient activation / deactivation mechanisms for secondary cell groups (SCGs) and secondary cells (SCells) is being considered.

[0004] "Revised WID on Further Multi-RAT Dual-Connectivity enhancements", RP-201040, 3GPP TSG RAN Meeting #88e, 3GPP, June 2020

[0005] However, since it is not clear under what conditions the activation / deactivation of the SCG should be performed, the terminal and the radio base station are unable to activate (trigger) the activation / deactivation of the SCG at the appropriate time.

[0006] Therefore, the following disclosure has been made in consideration of this situation, and aims to provide a radio base station, a radio communication system, and a radio communication method that can more reliably perform efficient SCG activation / deactivation.

[0007] One aspect of the present disclosure is a terminal (UE200) comprising a transmitter (RRC processing unit 220) that transmits a message including a deactivation request for a secondary cell group to a network, and a control unit (control unit 240) that performs deactivation of the secondary cell group based on the transmission of the deactivation request.

[0008] One aspect of the present disclosure is a radio base station (e.g., eNB100A) that includes a control unit (control unit 140) that determines whether deactivation of a secondary cell group is necessary based on the amount of data intended for a terminal (UE200) in a master node, and a transmission unit (RRC processing unit 120, DC processing unit 130) that transmits a message including a deactivation request for the secondary cell group when the deactivation is necessary.

[0009] One aspect of the present disclosure is a radio base station (e.g., gNB100B) that includes a control unit (control unit 140) that determines whether deactivation of a secondary cell group is necessary based on the amount of data intended for a terminal (UE200) in a secondary node, and a transmission unit (RRC processing unit 120, DC processing unit 130) that transmits a message including a request to deactivate the secondary cell group when the amount of data falls below a threshold.

[0010] One aspect of the present invention is a radio base station (e.g., eNB100A) that includes a receiving unit (DC processing unit 130) that receives an inactive indication of a secondary cell group from a terminal (UE200), and a transmitting unit (DC processing unit 130) that, when receiving the inactive indication, transmits a message including the inactive indication of the secondary cell group to a secondary node.

[0011] One aspect of the present invention is a radio base station (e.g., gNB100B) that includes a receiving unit (DC processing unit 130) that receives a message including an indication of inactivity of a secondary cell group, and a control unit (control unit 140) that, when receiving the message, stops sending activation requests for the secondary cell group until a specified time has elapsed.

[0012] FIG. 1 is a diagram illustrating an overall schematic configuration of a wireless communication system 10. FIG. 2 is a functional block diagram of an eNB 100A. FIG. 3 is a functional block diagram of a UE 200. FIG. 4 is a diagram illustrating an example of a communication sequence according to an SCG deactivation / activation procedure according to an operation example 1. FIG. 5 is a diagram illustrating an example of a communication sequence according to an MN-initiated SCG deactivation / MN-initiated SCG activation procedure according to an operation example 2. FIG. 6 is a diagram illustrating an example of a communication sequence according to an SN-initiated SCG deactivation / SN-initiated SCG activation procedure according to an operation example 3. FIG. 7 is a diagram illustrating an example of a MAC-CE configuration (part 1) according to the operation example. FIG. 8 is a diagram illustrating an example of a MAC-CE configuration (part 2) according to the operation example. FIG. 9 is a diagram illustrating an example of an RRC Reconfiguration configuration (part). FIG. 10 is a diagram illustrating an example of a CellGroupConfig configuration (part). FIG. 11 is a diagram illustrating an example of a CG-ConfigInfo configuration (part). FIG. 12 is a diagram illustrating an example of an RRC Connection Reconfiguration configuration (part). Fig. 13 is a diagram showing a configuration example (part) of an S-NODE MODIFICATION REQUEST. Fig. 14 is a diagram showing a configuration example (part) of an S-NODE MODIFICATION REQUIRED. Fig. 15 is a diagram showing an example of a communication sequence in accordance with a UE autonomously triggered SCG deactivation procedure according to operation example 4. Fig. 16 is a diagram showing an example of the hardware configuration of eNB100A, gNB100B, and UE200.

[0013] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0014] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0015] (1) Overall Schematic Configuration of Wireless Communication System FIG. 1 is a diagram showing the overall schematic configuration of a wireless communication system 10 according to this embodiment. The wireless communication system 10 is a wireless communication system conforming to Long Term Evolution (LTE) and 5G New Radio (NR). Note that LTE may also be called 4G, and NR may also be called 5G. Furthermore, the wireless communication system 10 may be a wireless communication system conforming to a scheme called Beyond 5G, 5G Evolution, or 6G.

[0016] LTE and NR may be interpreted as radio access technologies (RATs), and in this embodiment, LTE may be referred to as the first radio access technology, and NR may be referred to as the second radio access technology.

[0017] The wireless communication system 10 includes an Evolved Universal Terrestrial Radio Access Network 20 (hereinafter referred to as E-UTRAN 20) and a Next Generation-Radio Access Network 30 (hereinafter referred to as NG RAN 30). The wireless communication system 10 also includes a terminal 200 (hereinafter referred to as UE 200, User Equipment).

[0018] The E-UTRAN 20 includes an eNB 100A, which is a radio base station conforming to LTE. The NG RAN 30 includes a gNB 100B, which is a radio base station conforming to 5G (NR). Note that the E-UTRAN 20 and the NG RAN 30 (which may be eNB 100A or gNB 100B) may simply be referred to as a network.

[0019] The eNB100A, gNB100B and UE200 are capable of supporting carrier aggregation (CA) using multiple component carriers (CCs), and dual connectivity, which simultaneously transmits component carriers between multiple NG-RAN nodes and the UE.

[0020] The eNB100A, gNB100B and UE200 perform wireless communication via a radio bearer, specifically, a Signaling Radio Bearer (SRB) or a Data Radio Bearer (DRB).

[0021] In this embodiment, the eNB100A constitutes the master node (MN) and the gNB100B constitutes the secondary node (SN), and executes Multi-Radio Dual Connectivity (MR-DC), specifically E-UTRA-NR Dual Connectivity (EN-DC).

[0022] In other words, UE200 supports dual connectivity connecting to eNB100A and gNB100B.

[0023] The eNB 100A is included in a master cell group (MCG), and the gNB 100B is included in a secondary cell group (SCG). In other words, the gNB 100B is an SN included in the SCG.

[0024] The eNB100A and the gNB100B may also be referred to as radio base stations or network devices.

[0025] Furthermore, activation / deactivation of an SCG (which may be interpreted as an SCell) is supported in the wireless communication system 10. For example, the wireless communication system 10 may support signaling that realizes efficient activation / deactivation of one SCG and / or SCell.

[0026] The MN initiated SN modification procedure can be used to support SCG (de)activation, and the SN may decide whether to accept or reject the SCG (de)activation request after receiving the SN modification request message.

[0027] In addition, the activity notification message (Activation notification) sent from the SN to the MN may be used by the MN to make a final decision regarding SCG (de)activation. For example, a new SCG (de)activation information element (IE) may be added.

[0028] (2) Functional Block Configuration of Wireless Communication System Next, a functional block configuration of the wireless communication system 10 will be described. Specifically, the functional block configuration of the eNB 100A and the UE 200 will be described.

[0029] (2.1) eNB100A Fig. 2 is a functional block diagram of the eNB100A. As shown in Fig. 2, the eNB100A includes a radio communication unit 110, an RRC processing unit 120, a DC processing unit 130, and a control unit 140. Note that although the gNB100B supports a different communication method, it may have a block configuration generally similar to that of the eNB100A.

[0030] The wireless communication unit 110 transmits downlink signals (DL signals) conforming to LTE, and also receives uplink signals (UL signals) conforming to LTE.

[0031] The RRC processing unit 120 executes various processes in the radio resource control layer (RRC). Specifically, the RRC processing unit 120 can transmit an RRC Reconfiguration to the UE 200. Furthermore, the RRC processing unit 120 can receive an RRC Reconfiguration Complete from the UE 200, which is a response to the RRC Reconfiguration.

[0032] In this embodiment, the eNB 100A supports LTE. In this case, the name of the RRC message may be RRC Connection Reconfiguration or RRC Connection Reconfiguration Complete.

[0033] Furthermore, when deactivation of an SCG is necessary, the RRC processing unit 120 may transmit a message including a request to deactivate the SCG. In this embodiment, the RRC processing unit 120 may constitute a transmission unit.

[0034] Specifically, the RRC processing unit 120 may transmit an RRC Reconfiguration in which secondaryCellGroupState or mrdc-SecondaryCellGroupState is deactivated to the UE 200. Furthermore, the RRC processing unit 120 can transmit and receive various RRC messages to and from the UE 200 or the gNB 100B.

[0035] The DC processing unit 130 performs processing related to dual connectivity, specifically, Multi-RAT Dual Connectivity (MR-DC). In this embodiment, the eNB 100A supports LTE and the gNB 100B supports NR, so the DC processing unit 130 may perform processing related to E-UTRA-NR Dual Connectivity (EN-DC). Note that the type of DC is not limited, and may correspond to, for example, NR-E-UTRA Dual Connectivity (NE-DC) or NR-NR Dual Connectivity (NR-DC).

[0036] The DC processing unit 130 can transmit and receive messages specified in 3GPP TS37.340 and the like, and perform processing related to setting up and releasing DC between the eNB100A, the gNB100B, and the UE200.

[0037] In particular, in this embodiment, when deactivation of an SCG is required, the DC processing unit 130 may transmit a message including a request to deactivate the SCG. In this embodiment, the DC processing unit 130 may constitute a transmission unit.

[0038] Specifically, the DC processing unit 130 may transmit a medium access control layer (MAC) message indicating a deactivation request of the SCG to the UE 200. More specifically, the DC processing unit 130 may transmit a MAC-CE (Control Element) indicating a deactivation request of the SCG to the UE 200.

[0039] Alternatively, the DC processing unit 130 may send a message to the gNB100B (SN) including a request to deactivate the SCG.

[0040] In addition, when the amount of data for UE200 in the SN falls below a predetermined threshold, the DC processing unit 130 may send a message to the gNB100B (SN) including a request to deactivate the SCG.

[0041] The DC processing unit 130 may receive an SCG deactivation indication from the UE 200. In this embodiment, the DC processing unit 130 may configure a receiving unit. Specifically, when the UE 200 autonomously deactivates the SCG for some reason (for example, overheating), the DC processing unit 130 may receive a message including a deactivation indication indicating that the SCG has been deactivated (SCG is deactivated). Note that this message may be sent from an upper layer such as an RRC layer, or may be sent from a MAC layer, etc.

[0042] When the DC processing unit 130 receives the inactive indication, the DC processing unit 130 may transmit a message including the inactive indication of the SCG to the SN (e.g., the gNB 100B). In this embodiment, the DC processing unit 130 may configure a transmission unit that transmits the message including the inactive indication to the SN.

[0043] Specifically, the DC processing unit 130 may send a message including information indicating that the SCG has been deactivated, for example, an S-NODE MODIFICATION REQUEST (which may also be referred to as an SN Modification request), to the SN.

[0044] In addition, the DC processing unit 130 may send a message (S-NODE MODIFICATION REQUEST) including timer information (which may be called waitTimer) used to wait for the transmission of an SCG activation request (e.g., an SCG activation request).

[0045] The control unit 140 controls each functional block constituting the eNB 100A, and in this embodiment, in particular, executes control relating to addition or change of a secondary node.

[0046] Specifically, the control unit 140 may determine whether or not deactivation of the SCG is necessary based on the amount of data destined for the UE 200 in the master node (MN).

[0047] Alternatively, the control unit 140 may determine whether or not deactivation of the SCG is necessary based on the amount of data destined for the UE 200 in the secondary node (SN).

[0048] Here, the amount of data intended for the UE 200 may include at least one of user data transmitted from the UE 200 to a destination via a network and data transmitted from the destination to the UE 200.

[0049] The control unit 140 may determine that deactivation of the SCG is necessary when the amount of data falls below a predetermined threshold. Alternatively, the control unit 140 may determine that activation of the SCG is necessary when the amount of data exceeds a predetermined threshold (which does not necessarily have to match the threshold for determining deactivation). Alternatively, the amount of data may be based on the number of PDU (Protocol Data Unit) sessions.

[0050] In this embodiment, the channels include a control channel and a data channel, such as a physical downlink control channel (PDCCH), a physical uplink control channel (PUCCH), a physical random access channel (PRACH), and a physical broadcast channel (PBCH).

[0051] The data channels include a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH).

[0052] The reference signal includes a Demodulation Reference Signal (DMRS), a Sounding Reference Signal (SRS), a Phase Tracking Reference Signal (PTRS), and a Channel State Information-Reference Signal (CSI-RS), and the signal includes a channel and a reference signal. Furthermore, the data may refer to data transmitted via a data channel.

[0053] In addition, when the eNB 100A configures the SN, the control unit 140 may determine that the SCG needs to be deactivated when data transmission and reception via a radio bearer terminated in the SN (SN terminated bearer) is completed.

[0054] Furthermore, when the eNB 100A configures the SN (or when the gNB 100B configures the SN), the above-described DC processing unit 130 may receive a message including an SCG inactive indication (for example, an S-NODE MODIFICATION REQUEST (which may also be referred to as an SN Modification request)). In this case, the DC processing unit 130 may configure a receiving unit that receives a message including an SCG inactive indication.

[0055] Furthermore, when the control unit 140 receives a message including an indication that the SCG is inactive, the control unit 140 may stop sending an SCG activation request until a specified time has elapsed. For example, when the DC processing unit 130 receives a message (S-NODE MODIFICATION REQUEST) including timer information (which may be referred to as waitTimer), the control unit 140 may not transmit an SCG activation request (e.g., an SCG activation request) until a specified time (predetermined time) set based on the timer information has elapsed.

[0056] (2.2) UE 200 Fig. 3 is a functional block diagram of the UE 200. As shown in Fig. 3, the UE 200 includes a radio communication unit 210, an RRC processing unit 220, a DC processing unit 230, and a control unit 240.

[0057] The radio communication unit 210 transmits an uplink signal (UL signal) conforming to LTE or NR. The radio communication unit 210 also receives an uplink signal (UL signal) conforming to LTE. That is, the UE 200 can access the eNB 100A (E-UTRAN 20) and the gNB 100B (NG RAN 30) and can support dual connectivity (specifically, EN-DC).

[0058] The RRC processing unit 220 executes various processes in the radio resource control layer (RRC). Specifically, the RRC processing unit 220 can send and receive messages in the radio resource control layer.

[0059] As described above, the RRC processing unit 220 can receive RRC Reconfiguration from the network, specifically, the E-UTRAN 20 (or the NG RAN 30). The RRC processing unit 220 can also transmit RRC Reconfiguration Complete, which is a response to the RRC Reconfiguration, to the network.

[0060] Furthermore, the RRC processing unit 220 may transmit a message including a request to deactivate the SCG to the network. In this embodiment, the RRC processing unit 220 may constitute a transmission unit.

[0061] For example, the RRC processing unit 220 may transmit UEAssistanceInformation including an instruction to deactivate SCG (deactivation request) in the overheatingAssistance field to the network.

[0062] The DC processing unit 230 performs processing related to dual connectivity, specifically, MR-DC. As described above, in this embodiment, the DC processing unit 230 may perform processing related to EN-DC, but may also support NE-DC and / or NR-DC.

[0063] The DC processing unit 230 can access each of the eNB100A and the gNB100B and perform configurations at multiple layers including RRC (such as the medium access control layer (MAC), the radio link control layer (RLC), and the packet data convergence protocol layer (PDCP)).

[0064] Furthermore, the DC processing unit 230 executes control and data transmission / reception related to MR-DC using multiple types of radio bearers, specifically, SRB and DRB as described above.

[0065] SRB includes SRB0 to SRB3, which may be defined as follows:

[0066] SRB0: A radio bearer for RRC messages that uses the CCCH (Common Control Channel) logical channel.

[0067] SRB1: Radio bearer for RRC messages (which may include piggybacked NAS messages) and NAS messages before the establishment of SRB2, which uses the Dedicated Control Channel (DCCH) logical channel.

[0068] SRB2: Radio bearer for NAS messages using all DCCH logical channels. SRB2 has a lower priority than SRB1 and is always configured by the network after security is activated.

[0069] SRB3: A radio bearer for specific RRC messages when the UE 200 is in the MR-DC state, and uses the DCCH logical channel.

[0070] The DC processing unit 230 may transmit a message including a deactivation request to the SN when a radio bearer for a specific message is set in the dual connectivity state of the UE 200. Here, the radio bearer for the specific message in the dual connectivity state may be the above-mentioned SRB3.

[0071] The control unit 240 controls each functional block constituting the UE 200. In particular, in this embodiment, the control unit 240 executes control related to activation / deactivation of the SCG (SCell).

[0072] Specifically, the control unit 240 performs deactivation of the SCG based on sending a request to deactivate the SCG to the network.

[0073] More specifically, the control unit 240 transmits UEAssistanceInformation including an instruction to deactivate SCG (deactivation request) in the overheatingAssistance field, and then cooperates with the network (MN and / or SN) to deactivate the SCG.

[0074] (3) Operation of the Wireless Communication System Next, a description will be given of the operation of the wireless communication system 10. Specifically, a description will be given of the operation related to efficient activation / deactivation of the SCG and / or SCell.

[0075] In the operation examples 1 to 3 described below, the timing at which SCG activation / deactivation is activated (triggered) is clear, and eNB100A, gNB100B and UE200 perform SCG activation / deactivation at that timing.

[0076] (3.1) Operation Example 1 Fig. 4 shows an example of a communication sequence according to the SCG deactivation / activation procedure according to Operation Example 1. Specifically, Fig. 4 shows an example of a communication sequence according to the MN-initiated SCG deactivation / activation procedure.

[0077] In this operation example, the deactivation of the SCG is initiated by the UE 200. As shown in Fig. 4, the UE 200 can send UEAssistanceInformation including information about a power saving request (step 1).

[0078] Here, the UE 200 may transmit UEAssistanceInformation including an indication of deactivate SCG in overheatingAssistance to the MN. In accordance with the UEAssistanceInformation, deactivation of the SCG is performed (steps 2 to 5).

[0079] Here, if SRB3 is not configured, the UE 200 may send an indication of deactivate SCG to the MN, and the MN may decide to deactivate the SCG.

[0080] The MN may deactivate the SCG in any of the following ways:

[0081] The MN deactivates secondaryCellGroupState or mrdc-SecondaryCellGroupState during RRC Reconfiguration and transmits it to the UE 200 (see FIG. 9).

[0082] The MN sends an S-NODE MODIFICATION REQUEST (which may also be referred to as an SN Modification request) (which includes a deactivate SCG IE and includes deactivate SCG in the CGConfigInfo in the deactivate SCG IE) to the SN, requesting the SN to deactivate the SCG.

[0083] The SN sets secondaryCellGroupstate in RRC Reconfiguration to deactivated (or deactivates SpCellState in cellGroupConfig) and returns an SN Modification request Ack (includes SN RRCReconfiguration in scg-CellGroupConfig in CG-Config) to the MN. The SN may also return an SN Modification request Reject (rejects SCG deactivation).

[0084] When the MN receives the Ack from the SN, the MN may transmit an RRC Reconfiguration (encapsulated SN RRC Reconfiguration) to the UE 200.

[0085] The MN may send an activation notification (including an indication to deactivate the SCG) to the SN, and the SN may deactivate the SCG using MAC CE (see Figures 7 and 8). In addition to the MAC CE, one bit for SCG activation / deactivation may be generated and notified in PDCCH DCI (Downlink Control Information).

[0086] The MN may directly transmit a MAC CE including an indication to deactivate the SCG to the UE 200.

[0087] On the other hand, if SRB3 is configured, UE 200 may send the above-mentioned overheatingAssistance indication in UEAssistanceInformation to the SN, and the SN may decide to deactivate the SCG.

[0088] The SN may deactivate the SCG in one of the following ways:

[0089] - The SN sets the secondaryCellGroup state during RRC Reconfiguration to deactivated and transmits it to the UE 200.

[0090] The SN may deactivate the SCG using the MAC CE.

[0091] The SN sends an S-NODE MODIFICATION REQUIRED (which may also be called SN Modification required) (which includes a deactivate SCG IE and deactivates the secondaryCellGroupstate or deactivates the SpCellState in the cellGroupConfig) to the MN. The MN may also send an RRC Reconfiguration (encapsulated SN RRC Reconfiguration) to the UE 200.

[0092] The SN may transmit an activation notification (including an indication to deactivate the SCG) to the MN, and the MN may transmit an indication instructing SCG deactivation by the MAC CE to the UE 200. In addition to the MAC CE, one bit for SCG activation / deactivation may be generated in the PDCCH DCI and notified.

[0093] When the MN receives the Activation notification, it may deactivate secondaryCellGroupState or mrdc-SecondaryCellGroupState in the RRC Reconfiguration and transmit it to the UE 200.

[0094] It should be noted that the above-described operations may be applied not only to SCG deactivation but also to SCG activation.

[0095] (3.2) Operation Example 2 Fig. 5 shows an example of a communication sequence according to the MN initiated SCG deactivation / MN initiated SCG activation procedure according to Operation Example 2. Specifically, the upper part of Fig. 5 shows an example of a communication sequence related to MN initiated SCG deactivation, and the lower part of Fig. 5 shows a communication sequence related to MN initiated SCG activation.

[0096] As shown in FIG. 5, when the amount of data via the MN terminated bearer decreases and the MN determines that the MN terminated SCG resource is no longer necessary, SCG deactivation may be triggered (steps 1 and 2).

[0097] Here, the MN may set a predetermined threshold and start deactivation of the SCG when the amount of data for the UE 200 falls below the threshold. Alternatively, the MN may start SCG activation when the amount of data exceeds a predetermined threshold (which does not necessarily have to match the deactivation threshold). As described above, the amount of data may be based on the number of PDU sessions.

[0098] The MN may deactivate the SCG in any of the following ways:

[0099] - The secondaryCellGroupState or mrdc-SecondaryCellGroupState during RRC Reconfiguration is deactivated and transmitted to the UE 200 (see FIG. 9).

[0100] The MN sends an SN Modification request (including a deactivate SCG IE, and the deactivate SCG is included in CGConfigInfo in the deactivate SCG IE) to the SN, requesting the SN to deactivate the SCG.

[0101] The SN sets secondaryCellGroupstate in RRC Reconfiguration to deactivated (or deactivates SpCellState in cellGroupConfig) and returns an SN Modification request Ack (includes SN RRCReconfiguration in scg-CellGroupConfig in CG-Config) to the MN. The SN may also return an SN Modification request Reject (rejects SCG deactivation).

[0102] When the MN receives the Ack from the SN, the MN may transmit an RRC Reconfiguration (encapsulated SN RRC Reconfiguration) to the UE 200.

[0103] The MN sends an activation notification (including an indication to deactivate the SCG) to the SN, and the SN determines whether or not SCG deactivation is required. If the SN determines that SCG deactivation is required, the SN may deactivate the SCG via MAC CE (see Figures 7 and 8).

[0104] Furthermore, after receiving the Activation notification, the SN transmits an SN Modification required (which includes a deactivate SCG IE and sets the secondaryCellGroupState to deactivated or deactivates the SpCellState in the cellGroupConfig) to the scg-CellGroupConfig in the CG-Config) to the MN. The MN may also transmit an RRC Reconfiguration (encapsulated SN RRC Reconfiguration) to the UE 200.

[0105] The MN may directly transmit a MAC CE including an indication to deactivate the SCG to the UE 200. In addition to the MAC CE, one bit for SCG activation / deactivation may be generated in PDCCH DCI (Downlink Control Information) and notified.

[0106] It should be noted that the above-described operations may be applied not only to SCG deactivation but also to SCG activation.

[0107] (3.3) Operation Example 3 Fig. 6 shows an example of a communication sequence according to the SN Initiated SCG deactivation / SN Initiated SCG activation procedure according to Operation Example 3. Specifically, the upper part of Fig. 6 shows an example of a communication sequence related to SN Initiated SCG deactivation, and the lower part of Fig. 6 shows an example of a communication sequence related to SN Initiated SCG activation.

[0108] As shown in Figure 6, when data transmission / reception via the SN terminated bearer is terminated and the SN determines that the SN terminated SCG resource is no longer required, SCG deactivation may be triggered (steps 1 and 2). However, even if data transmission / reception via the SN terminated bearer is not necessarily terminated, the amount of data per unit time may be increased (steps 1 and 2).

[0109] The SN may deactivate the SCG in one of the following ways:

[0110] - If SRB3 is set, the SN sets the secondaryCellGroupstate during RRC Reconfiguration to deactivated and transmits it to the UE200.

[0111] The SN may deactivate the SCG via MAC CE (see Figures 7 and 8).

[0112] The SN sends an SN Modification required (including a deactivate SCG IE and deactivating the secondaryCellGroupstate or deactivating the SpCellState in the cellGroupConfig) to the MN. The MN may also send an RRC Reconfiguration (encapsulated SN RRC Reconfiguration) to the UE 200.

[0113] The MN may return an S-NODE MODIFICATION REFUSE to the SN (rejecting the SCG deactivation).

[0114] The SN may transmit an activation notification (including an indication to deactivate the SCG) to the MN, and the MN may transmit an indication instructing SCG deactivation by the MAC CE to the UE 200. In addition to the MAC CE, one bit for SCG activation / deactivation may be generated in the PDCCH DCI and notified.

[0115] When the MN receives the Activation notification, it may deactivate secondaryCellGroupState or mrdc-SecondaryCellGroupState in the RRC Reconfiguration and transmit it to the UE 200.

[0116] It should be noted that the above-described operations may be applied not only to SCG deactivation but also to SCG activation.

[0117] (3.4) Message Configuration Example Fig. 7 shows a configuration example (part 1) of a MAC-CE according to the above-described operation example. Specifically, the upper part of Fig. 7 shows a configuration example of a 1-octet SCell Activation / Deactivation MAC CE. The lower part of Fig. 7 shows a configuration example of a 4-octet SCell Activation / Deactivation MAC CE. The configuration of this MAC-CE is specified in 3GPP TS38.321 Chapter 6.1.3.10.

[0118] The MAC-CE may be transmitted by the SN. As shown in Figure 7, the reserved (R) bit may be changed to "P". "P" may refer to a Primary SCell (PSCell) included in the SCG. A PSCell may be interpreted as a type of SCell.

[0119] For example, a P field set to '1' may indicate that the PSCell is activated, and a P field set to '0' may indicate that the PSCell is deactivated.

[0120] Fig. 8 shows a second example of the configuration of a MAC-CE according to the operation example. As shown in Fig. 8, a new MAC-CE to be used for deactivating an SCG may be defined.

[0121] The MAC-CE may be sent by the MN or the SN. "S" means SCG. When the S field is set to "1", it may indicate that the SCG is activated, and when the S field is set to "0", it may indicate that the SCG is deactivated.

[0122] 9 to 14 show example configurations of RRC messages related to the above-described operation examples. Specifically, Fig. 9 shows a (partial) example configuration of RRC Reconfiguration. As shown in Fig. 9, RRC Reconfiguration may specify secondaryCellGroupState, mrdc-SecondaryCellGroupState, and the like that can support activation / deactivation of SCG (SCell).

[0123] Fig. 10 shows a configuration example (part) of CellGroupConfig. As shown in Fig. 10, in CellGroupConfig, spCellStatte that can support activation / deactivation of SCG (SCell) may be defined.

[0124] Fig. 11 shows a configuration example (part) of CG-ConfigInfo. As shown in Fig. 11, CG-ConfigInfo may define SecondaryCellGroupState that can support activation / deactivation of SCG (SCell).

[0125] Fig. 12 shows a configuration example (part) of RRC Connection Reconfiguration. As shown in Fig. 12, in RRC Connection Reconfiguration, nr-SecondaryCellGroupConfig that can support deactivation of SCG (SCell) may be defined.

[0126] Fig. 13 shows a configuration example (part) of an S-NODE MODIFICATION REQUEST. As shown in Fig. 13, the S-NODE MODIFICATION REQUEST may specify Deactivate activate SCG, which can support deactivation of an SCG (SCell).

[0127] Fig. 14 shows a configuration example (part) of S-NODE MODIFICATION REQUIRED. As shown in Fig. 14, S-NODE MODIFICATION REQUIRED may specify Deactivate activate SCG, which can support deactivation of SCG (SCell).

[0128] Note that S-NODE MODIFICATION REQUEST and S-NODE MODIFICATION REQUIRED are specified in 3GPP TS38.423 Chapters 9.1.2.5 and 9.1.2.8.

[0129] (3.5) Operation Example 4 In this operation example, an operation will be described in which the UE 200 autonomously activates / deactivates an SCG (or an SCell) (SCG deactivation / activation) due to some reason such as overheating. Note that such an operation of the UE 200 may be referred to as UE autonomously triggered SCG deactivation / deactivation.

[0130] When the UE autonomously triggers SCG deactivation / deactivation, it is necessary to specify an inter-node message transmitted and received between the MN and the SN.

[0131] In addition, in the case of a radio bearer terminated in the SN (SN terminated bearer), for example, it is assumed that the UE 200 deactivates the SCG (SCell) due to an overload or no uplink data (no UL data) state, and transmits a message including a deactivation indication indicating that the SCG has been deactivated (SCG is deactivated) to the MN.

[0132] In this case, the MN instructs the SN to deactivate the SCG (SCell) by an S-NODE MODIFICATION REQUEST (which may also be referred to as an SN modification request). However, for example, when downlink data occurs on the SN side, the SN requests the MN to activate the SCG by an S-NODE MODIFICATION REQUIRED (which may also be referred to as an SN modification required). Upon receiving such a request, the MN requests the UE 200 to reactivate the SCG. If such an event is repeated, a so-called ping-pong state occurs.

[0133] In addition, in the case of SCG deactivation triggered by the MN, the SN may be able to reject the SCG deactivation due to the SN modification request transmitted from the MN. However, in the case of SCG deactivation triggered by the UE 200, since the SCG has already been deactivated, if the SN rejects the SCG deactivation due to the SN modification request transmitted from the MN, an SCG state mismatch may occur between the UE 200 and the SN.

[0134] An example of operation that can solve this problem will be described below. Specifically, the UE 200, the MN, and the SN may operate as follows.

[0135] (i) When the MN receives an SCG deactivation indication (SCG is deactivated) from the UE 200, the MN may send the SCG deactivation indication (SCG is deactivated) to the SN using an SN modification request.

[0136] The SN modification request may also include timer information (which may be referred to as a waitTimer) used to wait for transmission of an SCG activation request. Note that the UE 200 may also transmit an SCG inactivity indication to the SN.

[0137] (ii) When the MN sends an SN modification request to the SN, it may indicate that the SCG has already been deactivated by the autonomous operation of the UE 200 (SCG is deactivated (UE already autonomously deactivated the SCG)). However, an SN receiving such an SN modification request cannot reject the SCG deactivation by the SN modification request.

[0138] Alternatively, the SN may be configured to be able to set only deactivated in the SCG activation / deactivation result flag included in the SN modification request ack returned to the MN.

[0139] Also, when the MN sends an SN modification request as described above to the SN, it may assume that the SN cannot reject the SCG deactivation.

[0140] FIG. 15 shows an example of a communication sequence according to the UE autonomously triggered SCG deactivation procedure according to the fourth operation example.

[0141] As shown in Figure 15, the UE 200 may autonomously deactivate the SCG for some reason (step 1), such as UE 200 overheating, no UL data, power saving, UE S-RLF (Radio Link Failure of SCG) for which the SCG is deactivated, etc.

[0142] The UE 200 may notify the MN that the SCG is deactivated (step 2). Specifically, the UE 200 may notify the MN that the SCG is deactivated by an RRC message, MAC-CE, or physical layer (L1) signaling. Note that, as described above, the UE 200 may notify the SN of the same information.

[0143] In response to the notification from UE 200, the MN may transmit an SN modification request to the SN (step 3). Specifically, the MN may transmit an SN modification request including an SCG deactivation indication (SCG is deactivated) to the SN. Note that, instead of the SN modification request, other inter-node messages (e.g., S-NODE MODIFICATION REQUEST, S-NODE MODIFICATION REQUEST) may be used.

[0144] The MN may also include a value of waitTimer in the SN modification request. The waitTimer may be interpreted as a setting value of a timer that causes the SN to wait for a predetermined time before transmitting an SCG activation request, specifically, an S-NODE MODIFICATION REQUIRED (SN modification required). In other words, the SN cannot transmit an SCG activation request, for example, an S-NODE MODIFICATION REQUIRED (SN modification required) including an SCG activation request, until the time set by the waitTimer expires.

[0145] The waitTimer may be started when the SN receives an SN modification request including an SCG deactivation indication (SCG is deactivated). The waitTimer may be stopped, for example, when the SN receives a RACH request from the UE 200 (when the UE 200 transmits a RACH request to the SN).

[0146] Furthermore, the value of the waitTimer does not need to be explicitly indicated by the MN. For example, the SN may start the waitTimer in response to receiving an SN modification request. The setting value of the waitTimer may be set by signaling such as an upper layer, or may be set in the SN in advance.

[0147] In response to receiving the SN modification request, the SN may return an SN modification request Ack to the MN (step 4).

[0148] It should be noted that a timer may be provided on the MN side in step 2. Specifically, when the MN receives an indication of SCG deactivation (SCG is deactivated) from the UE 200, the MN may start a waitTimer.

[0149] Even if DL data occurs in the MN terminated bearer or an SCG activation request occurs from the SN before the expiration of the waitTimer, the MN does not transmit an SCG activation request to the UE 200. Note that if an SCG activation request is transmitted from the SN in response to SN modification required before the expiration of the waitTimer, the MN may return an SN modification refuse to the SN.

[0150] (4) Actions and Effects According to the above-described embodiment, the following actions and effects can be obtained: Specifically, the UE 200 can transmit a message (UEAssistanceInformation) including a request to deactivate the SCG to the network.

[0151] In addition, eNB100A (MN) can determine whether deactivation of the SCG is necessary based on the amount of data for UE200 in the MN, and if deactivation is necessary, can send a message (e.g., S-NODE MODIFICATION REQUEST) including a request to deactivate the SCG.

[0152] Furthermore, the gNB100B (SN) can determine whether deactivation of the SCG is necessary based on the amount of data for the UE200 in the SN, and if the amount of data falls below a threshold, can send a message including a request to deactivate the SCG.

[0153] Therefore, the eNB100A, the gNB100B, and the UE200 can clearly and reliably determine the timing of activating / deactivating the SCG and can trigger the activation / deactivation of the SCG at an appropriate timing, thereby enabling efficient activation / deactivation of the SCG to be more reliably performed.

[0154] In this embodiment, when a radio bearer (SRB3) for a specific message is configured in the dual connectivity state of the UE 200, a message including a deactivation request can be transmitted to the SN, thereby realizing appropriate activation / deactivation of the SCG according to the dual connectivity state.

[0155] In this embodiment, for example, when eNB100A (MN) receives an SCG deactivation indication (SCG is deactivated) from UE200, it can send an SN modification request including the SCG deactivation indication (SCG is deactivated) to gNB100B (SN).

[0156] Furthermore, when the SN receives an SN modification request including an SCG deactivation indication (SCG is deactivated), the SN can stop sending SCG activation requests until, for example, a specified time set by waitTimer has elapsed. In this case, the MN may include timer information (the set value of waitTimer) used to wait for the transmission of an SCG activation request in the SN modification request.

[0157] Therefore, even if UE200 autonomously deactivates the SCG, it is possible to avoid a ping-pong state in which requests for SCG activation / deactivation are repeated, and a mismatch in the SCG state between UE200 and the SN.

[0158] (5) Other Embodiments The present invention has been described above with reference to examples. However, the present invention is not limited to these descriptions, and it will be obvious to those skilled in the art that various modifications and improvements are possible.

[0159] For example, in the above-described embodiment, an EN-DC in which the MN is an eNB and the SN is a gNB has been described as an example, but as described above, other DCs may be used. Specifically, it may be an NR-DC in which the MN is a gNB and the SN is a gNB, or an NE-DC in which the MN is a gNB and the SN is an eNB.

[0160] In addition, in the above-mentioned embodiment, an example of operation has been mainly described when deactivating an SCG, but this example of operation may also be applied to activation of an SCG, and may also be applied to activation / deactivation of an SCell (including a PSCell).

[0161] Furthermore, the block diagrams (FIGS. 2 and 3) used in the description of the above-described embodiments show functional blocks. These functional blocks (components) are realized by any combination of hardware and / or software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (e.g., wired, wireless, etc.) and these multiple devices. The functional block may also be realized by combining software with the single device or multiple devices.

[0162] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how each is implemented.

[0163] Furthermore, the above-described eNB100A, gNB100B, and UE200 (the devices) may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 16 is a diagram showing an example of the hardware configuration of the devices. As shown in Fig. 16, the devices may be configured as a computer including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0164] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the apparatus may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0165] Each functional block of the device (see Figure 2.3) is realized by any hardware element of the computer device or a combination of the hardware elements.

[0166] In addition, each function of the device is realized by loading specified software (programs) onto hardware such as processor 1001 and memory 1002, causing processor 1001 to perform calculations, control communication via communication device 1004, and control at least one of reading and writing data in memory 1002 and storage 1003.

[0167] The processor 1001 controls the entire computer by running, for example, an operating system, and may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control unit, an arithmetic unit, and registers.

[0168] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. Furthermore, the various processes described above may be executed by a single processor 1001, or may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0169] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 may store a program (program code), a software module, etc., capable of executing a method according to an embodiment of the present disclosure.

[0170] Storage 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned recording medium may be, for example, a database, a server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0171] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0172] The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize, for example, at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD).

[0173] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0174] Furthermore, each device such as the processor 1001 and the memory 1002 is connected to a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0175] Furthermore, the device may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0176] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0177] Each aspect / embodiment described in the present disclosure may be applied to at least one of a system using Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, a 4th generation mobile communication system (4G), a 5th generation mobile communication system (5G), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable system, and a next-generation system enhanced based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A and 5G) may also be applied.

[0178] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0179] In the present disclosure, a specific operation described as being performed by a base station may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal may be performed by at least one of the base station and another network node other than the base station (e.g., MME or S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, a combination of multiple other network nodes (e.g., MME and S-GW) may also be used.

[0180] Information, signals (information, etc.) may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input and output via multiple network nodes.

[0181] The input and output information may be stored in a specific location (for example, a memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added. The output information may be deleted. The input information may be transmitted to another device.

[0182] The determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0183] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0184] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0185] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0186] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0187] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0188] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0189] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0190] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0191] In this disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0192] A base station can accommodate one or more (e.g., three) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0193] The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0194] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0195] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0196] At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, etc. The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0197] Furthermore, a base station in the present disclosure may be read as a mobile station (user terminal, the same applies hereinafter). For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a mobile station is replaced with communication between multiple mobile stations (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the mobile station may be configured to have the functions of a base station. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0198] Similarly, a mobile station in the present disclosure may be interpreted as a base station, in which case the base station may have the functions of a mobile station.

[0199] A radio frame may consist of one or more frames in the time domain.

[0200] Each of the one or more frames in the time domain may be called a subframe, and the subframe may further be made up of one or more slots in the time domain.

[0201] A subframe may be of fixed time length (e.g., 1 ms) that is independent of numerology.

[0202] Numerology may be communication parameters that apply to the transmission and / or reception of a signal or channel, such as subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0203] A slot may consist of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol, etc.) A slot may be a numerology-based time unit.

[0204] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0205] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0206] For example, one subframe may be referred to as a transmission time interval (TTI), multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0207] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station schedules each user terminal to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) in TTI units. Note that the definition of TTI is not limited to this.

[0208] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0209] In addition, when one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling, and the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0210] A TTI having a time length of 1 ms may be referred to as a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be referred to as a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0211] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0212] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and may include one or more consecutive subcarriers in the frequency domain.

[0213] The number of subcarriers included in an RB may be the same regardless of the numerology, and may be, for example, 12. The number of subcarriers included in an RB may also be determined based on the numerology.

[0214] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI, each of which may consist of one or more resource blocks.

[0215] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0216] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0217] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0218] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0219] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a predetermined signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0220] The above-described structures of the radio frame, subframe, slot, minislot, and symbol are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, and other configurations may be changed in various ways.

[0221] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0222] The reference signal may also be abbreviated as Reference Signal (RS) and may be called a pilot depending on the applicable standard.

[0223] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0224] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0225] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way.

[0226] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0227] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0228] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0229] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0230] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0231] 10 Wireless communication system 20 E-UTRAN 30 NG RAN 100A eNB 100B gNB 110 Wireless communication unit 120 RRC processing unit 130 DC processing unit 140 Control unit 200 UE 210 Wireless communication unit 220 RRC processing unit 230 DC processing unit 240 Control unit 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus

Claims

1. A receiving unit that receives a first message including information indicating a deactivation request for a secondary cell group from a terminal; a transmitter for transmitting a second message to the secondary node, the second message including information requesting the secondary node to deactivate the secondary cell group; Equipped with The receiving unit receives a third message from the secondary node rejecting a deactivation request for the secondary cell group.

2. A radio base station as described in claim 1, wherein the first message is UEAssistanceInformation, the second message is S-NODE MODIFICATION REQUEST, and the third message is S-NODE MODIFICATON REQUEST REJECT.

3. A step of receiving a first message including information indicating a deactivation request for a secondary cell group from a terminal; sending a second message to the secondary node, the second message including information requesting the secondary node to deactivate the secondary cell group; A communication method for a radio base station, comprising the step of receiving a third message from the secondary node rejecting a request to deactivate the secondary cell group.

4. A communication system including a terminal, a first radio base station, and a second radio base station, The terminal includes: A transmitter that transmits a first message including information indicating a deactivation request for a secondary cell group to the first radio base station, The first radio base station, A receiving unit for receiving the first message from the terminal; a transmitter configured to transmit a second message to the second radio base station, the second message including information requesting the second radio base station to deactivate the secondary cell group; The second radio base station, a receiving unit for receiving the second message from the first radio base station; A communication system comprising: a transmitter configured to transmit a third message to the first radio base station rejecting a deactivation request for the secondary cell group.