Terminal and wireless communication system

Abstract

UE, according to the present invention, transmits and receives wireless resource control layer messages. The UE transmits dual connectivity information, including a wireless resource control layer reconfiguration message, to a network during a secondary cell addition or change procedure.

Description

[Technical Field]

[0001] The present invention relates to a terminal and a radio communication system for transmitting and receiving messages of a radio resource control layer. [Background technology]

[0002] The 3rd Generation Partnership Project (3GPP) has developed 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, in order to realize a more efficient addition or change of a Primary SCell (PSCell), support for a simplified conditional secondary cell (secondary node) addition / change procedure (conditional PSCell addition / change) is being considered. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] "Revised WID on Further Multi-RAT Dual-Connectivity enhancements", RP-201040, 3GPP TSG RAN Meeting #88e, 3GPP, June 2020 Summary of the Invention

[0005] However, the above-mentioned conditional PSCell addition / change has the following problems: For example, in the case of E-UTRA-NR Dual Connectivity (EN-DC), it is difficult to directly transmit a message (RRC Reconfiguration Complete) of the NR radio resource control layer (RRC) to the eNB, which is the master node (MN).

[0006] Furthermore, when the MN (eNB) receives the RRC Reconfiguration Complete from the terminal (User Equipment, UE), the MN cannot determine to which target secondary node (T-SN) the SgNB Reconfiguration Complete should be sent, nor can the MN determine which T-SN the UE has accessed.

[0007] Therefore, the following disclosure has been made in consideration of this situation, and aims to provide a terminal and a wireless communication system that can reliably add or change a secondary cell (secondary node) even when a conditional secondary cell (secondary node) addition or change procedure is applied in dual connectivity.

[0008] One aspect of the present disclosure is a terminal (UE200) that includes a transceiver unit (RRC processing unit 220) that transmits and receives messages of a radio resource control layer, and the transceiver unit transmits dual connectivity information including a reconfiguration message of the radio resource control layer to a network in a secondary cell addition or change procedure.

[0009] One aspect of the present disclosure is a terminal (UE200) that includes a transceiver unit (RRC processing unit 220) that transmits and receives messages of a radio resource control layer, and the transceiver unit transmits another message of the radio resource control layer, including a reconfiguration message of the radio resource control layer, to a network in a procedure for adding or changing a secondary cell. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the overall schematic configuration of a wireless communication system 10. As shown in FIG. [Figure 2] FIG. 2 is a functional block diagram of the eNB 100A. [Figure 3] FIG. 3 is a functional block diagram of the UE 200. [Figure 4] FIG. 4 is a diagram showing an example of a communication sequence (late data forwarding) according to a conventional conditional PSCell addition procedure. [Figure 5] FIG. 5 is a diagram showing an example of a communication sequence (early data forwarding) according to a conventional conditional PSCell addition procedure. [Figure 6] FIG. 6 is a diagram showing an example of a communication sequence (late data forwarding) in accordance with an SN-initiated conditional inter-SN PSCell change procedure. [Figure 7] FIG. 7 is a diagram illustrating an example of a part of a communication sequence using ULInformationTransferMRDC according to the first operation example. [Figure 8] FIG. 8 is a diagram illustrating an example of a part of a communication sequence using a new RRC message according to the second operation example. [Figure 9] FIG. 9 is a diagram illustrating an example of the configuration of CondReconfigToAddModList. [Figure 10] FIG. 10 is a diagram illustrating an example of the configuration of an NR ULInformationTransferMRDC message. [Figure 11] FIG. 11 is a diagram illustrating an example of the configuration of an LTE ULInformationTransferMRDC message. [Figure 12] FIG. 12 is a diagram illustrating an example of the hardware configuration of the eNB100A, the gNB100B, and the UE200. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] (1) Overall configuration of the wireless communication system 1 is a schematic diagram of the overall 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. The wireless communication system 10 may also be a wireless communication system conforming to a scheme called Beyond 5G, 5G Evolution, or 6G.

[0013] 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.

[0014] The wireless communication system 10 includes an Evolved Universal Terrestrial Radio Access Network 20 (hereinafter, E-UTRAN 20) and a Next Generation-Radio Access Network 30 (hereinafter, NG RAN 30). The wireless communication system 10 also includes a terminal 200 (hereinafter, UE 200, User Equipment).

[0015] 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.

[0016] The eNB100A, gNB100B and UE200 are capable of supporting carrier aggregation (CA) using multiple component carriers (CCs), and dual connectivity for simultaneously transmitting component carriers between multiple NG-RAN nodes and the UE.

[0017] The eNB100A, the gNB100B, and the UE200 perform wireless communication via a radio bearer, specifically, a Signaling Radio Bearer (SRB) or a DRB Data Radio Bearer (DRB).

[0018] 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).

[0019] In other words, UE200 supports dual connectivity connecting to eNB100A and gNB100B.

[0020] 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.

[0021] The eNB100A and the gNB100B may also be referred to as radio base stations or network devices.

[0022] Furthermore, the wireless communication system 10 may support conditional addition or change of a Primary SCell (PSCell). A PSCell is a type of secondary cell. A PSCell means a Primary SCell (secondary cell), and may be interpreted as corresponding to any SCell among multiple SCells.

[0023] The secondary cell may be read as a secondary node (SN) or a secondary cell group (SCG). The conditional PSCell addition / change can realize efficient and rapid addition or change of a secondary cell.

[0024] The conditional PSCell addition / change may be interpreted as a simplified procedure for adding / changing a conditional secondary cell.

[0025] Furthermore, a conditional inter-SN PSCell change procedure may be supported in the wireless communication system 10. Specifically, an MN-initiated conditional inter-SN PSCell change and / or an SN-initiated conditional inter-SN PSCell change may be supported.

[0026] (2) Functional block configuration of wireless communication system Next, a description will be given of the functional block configuration of the wireless communication system 10. Specifically, the functional block configurations of the eNB 100A and the UE 200 will be described.

[0027] (2.1) eNB100A 2 is a functional block diagram of the eNB 100 A. As shown in FIG. 2, the eNB 100 A includes a radio communication unit 110, an RRC processing unit 120, a DC processing unit 130, and a control unit 140.

[0028] The wireless communication unit 110 transmits downlink signals (DL signals) conforming to LTE, and also receives uplink signals (UL signals) conforming to LTE.

[0029] 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.

[0030] 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.

[0031] Furthermore, the RRC processing unit 120 may include a cell ID of the Target PSCell, for example, a Cell Global Identifier (CGI), for each condReconfigId in ConditionalReconfiguration included in the RRC Reconfiguration. The RRC layer of the UE 200 may be configured by such ConditionalReconfiguration. Note that, instead of the CGI, information capable of identifying the SN (gNB 100B) (which may be referred to as a gNB ID) may be used.

[0032] Furthermore, the RRC processing unit 120 may determine the SN (T-SN) to be added or changed based on the cell ID (e.g., NR Physical Cell ID (PCI), NR CGI, or gNB ID) included in the ULInformationTransferMRDC message transmitted from the UE 200.

[0033] Note that a new RRC message may be used instead of the ULInformationTransferMRDC message, and this RRC message may be called a bye-message.

[0034] As described later, SgNB Reconfiguration complete may be transmitted to the T-SN based on control by the control unit 140. Furthermore, the control unit 140 may identify the T-SN based on the cell ID of the Target PSCell transmitted from the UE 200 and the frequency band in NR.

[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] 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.

[0038] Specifically, the control unit 140 can determine whether to perform conditional PSCell addition / change (CPA / CPC) based on a measurement report from the UE 200.

[0039] When the control unit 140 determines the CPA / CPC, the control unit 140 may transmit an SN Addition Request to a target secondary node (T-SN). The control unit 140 may also receive an SN Addition Request Ack, which is a response to the SN Addition Request, from the T-SN.

[0040] In addition to CPA / CPC, when the source secondary node (S-SN) decides to perform an SN-initiated conditional inter-SN PSCell change (CPC), the control unit 140 may receive an SN change required from the S-SN. In addition, the control unit 140 may transmit an SN Addition Request to the T-SN in response to the SN change required.

[0041] In this embodiment, the channels include a control channel and a data channel. The control channels include a PDCCH (Physical Downlink Control Channel), a PUCCH (Physical Uplink Control Channel), a PRACH (Physical Random Access Channel), and a PBCH (Physical Broadcast Channel).

[0042] The data channels include a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH).

[0043] 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.

[0044] (2.2)UE200 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.

[0045] 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).

[0046] The RRC processing unit 220 executes various processes in the radio resource control layer (RRC). Specifically, the RRC processing unit 220 can transmit and receive messages in the radio resource control layer. In this embodiment, the RRC processing unit 220 constitutes a transmission and reception unit.

[0047] 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.

[0048] In this embodiment, the RRC processing unit 220 may transmit dual connectivity information including a radio resource control layer reconfiguration message to the network in a secondary cell addition or change procedure (conditional PSCell addition / change).

[0049] Specifically, the RRC processing unit 220 may transmit a ULInformationTransferMRDC message including an RRC Reconfiguration Complete to the network. Note that, as described above, the RRC Reconfiguration Complete may be an RRC Connection Reconfiguration Complete.

[0050] Also, normal UL information transfer may be used instead of ULInformationTransferMRDC.

[0051] Alternatively, the RRC processing unit 220 may transmit another radio resource control layer message including a radio resource control layer reconfiguration message to the network in the conditional PSCell addition / change.

[0052] Specifically, the RRC processing unit 220 may send a new RRC message (bye-message) to the RRC layer that includes the RRC Reconfiguration Complete, or may reuse an existing message in the RRC layer so that the RRC Reconfiguration Complete is included (i.e., embedded).

[0053] Furthermore, the RRC processing unit 220 may receive a message of the radio resource control layer that includes identification information of the SCell (which may include the PSCell) or the radio base station (gNB) that forms the SCell.

[0054] Specifically, the RRC processing unit 220 may receive an RRC Reconfiguration including the CGI (or gNB ID) of the Target PSCell as identification information. In response to the received RRC Reconfiguration, the RRC processing unit 220 may transmit dual connectivity information including the CGI (or gNB ID), specifically, a ULInformationTransferMRDC message, to the network.

[0055] Alternatively, the RRC processing unit 220 may transmit another message of the RRC layer including the CGI (or gNB ID) to the network in response to the received RRC Reconfiguration, specifically, the new RRC message (bye-message) described above.

[0056] 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.

[0057] 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)).

[0058] The control unit 240 controls each functional block constituting the UE 200. In particular, in this embodiment, the control unit 240 executes control relating to transmission and reception of RRC messages by the RRC processing unit 220 and control relating to DC by the DC processing unit 230.

[0059] Specifically, the control unit 240 may encode the cell ID (NR PCI, NR CGI, or gNB ID) of the Target PSCell that meets the conditions for addition or change in the LTE RRC layer, and transmit the above-mentioned ULInformationTransferMRDC message or a new RRC message (bye-message) to the network along with RRC Reconfiguration Complete.

[0060] In addition, encoding the cell ID of the Target PSCell may be interpreted as the processing required to include it in a ULInformationTransferMRDC message or a new RRC message, or may be interpreted as dual connectivity information (ULInformationTransferMRDC) or an RRC message that includes the cell ID (identification information).

[0061] (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 of the wireless communication system 10 regarding a conditional secondary cell (secondary node) addition / change procedure (conditional PSCell addition / change) and a conditional inter-SN PSCell change procedure (MN-initiated conditional inter-SN PSCell change / SN-initiated conditional inter-SN PSCell change).

[0062] (3.1) Examples of conventional operation and issues FIG. 4 shows an example of a communication sequence (late data forwarding) according to a conventional conditional PSCell addition procedure.

[0063] As shown in FIG. 4, in conditional PSCell addition (CPA), the MN (eNB 100A) determines whether or not CPA is possible (necessary) based on a Measurement Report from the UE 200 (step 2).

[0064] Here, when the MN is an eNB and the SN is a gNB, UE200 monitors the execution condition, and if a target PSCell that satisfies the execution condition exists, UE200 applies the RRC reconfiguration of the target PSCell and returns an RRC Reconfiguration Complete to the MN because it needs to send an RRC reconfiguration complete message to the SN via the MN (steps 7 and 8).

[0065] However, the UE 200 does not know how to transmit the NR RRC Reconfiguration Complete to the eNB, which is the MN (see the dotted line frame in the figure), and there is a problem in that the UE 200 cannot transmit the RRC Reconfiguration Complete.

[0066] Furthermore, when the MN (eNB) receives the RRC Reconfiguration Complete from the UE 200, the MN cannot determine to which target secondary node (T-SN) the SgNB Reconfiguration Complete (which may also be called SN Reconfiguration Complete) should be sent. In addition, the MN cannot determine which T-SN the UE 200 has accessed.

[0067] It should be noted that this problem is not limited to the case of late data forwarding shown in FIG. 4, but also applies to the case of early data forwarding.

[0068] FIG. 5 shows an example of a communication sequence (early data forwarding) according to a conventional conditional PSCell addition procedure.

[0069] In the example shown in FIG. 5, the UE 200 does not know how to transmit the NR RRC Reconfiguration Complete to the eNB, which is the MN (see the dotted line frame in the figure), and there is a problem in that the UE 200 cannot transmit the RRC Reconfiguration Complete.

[0070] Furthermore, this problem is not limited to conditional PSCell addition, but also applies to conditional inter-SN PSCell change.

[0071] Figure 6 shows an example of a communication sequence (late data forwarding) following the SN-initiated conditional inter-SN PSCell change procedure. forwarding).

[0072] As shown in FIG. 6, in the conditional PSCell change (CPC), the S-SN determines whether or not CPC is possible (necessary) based on the Measurement Report from the UE 200 (step 2).

[0073] In the example shown in FIG. 6, the UE 200 does not know how to transmit the NR RRC Reconfiguration Complete to the eNB, which is the MN (see the dotted frame in the figure), and there is a problem in that the UE 200 cannot transmit the RRC Reconfiguration Complete.

[0074] (3.2) Example of operation Below, several operation examples that can solve the problem of not being able to transmit the NR RRC Reconfiguration Complete described above will be described.

[0075] (3.2.1) Example 1 Fig. 7 shows an example of a part of a communication sequence using ULInformationTransferMRDC according to operation example 1. Fig. 7 corresponds to the example of a communication sequence (late data forwarding) according to the conditional PSCell addition shown in Fig. 4.

[0076] As shown in FIG. 7, UE 200 may embed an NR RRC message, specifically, an RRC Reconfiguration Complete, into an LTE ULInformationTransferMRDC.

[0077] At this time, UE200 may include the cell ID (CGI, etc.) of the Target PSCell (T-SN) or the identification information (gNB ID) of the gNB that configures the T-SN in ULInformationTransferMRDC.

[0078] Specifically, UE 200 may encode the cell ID (NR PCI, NR CGI, or gNB ID) of the Target PSCell in the RRC layer of LTE, and transmit a ULInformationTransferMRDC message including RRC Reconfiguration Complete and the cell ID (or gNB ID).

[0079] Note that, although FIG. 7 shows an example of late data forwarding, the transmission of such a ULInformationTransferMRDC message including RRC Reconfiguration Complete is not the same as the early data forwarding shown in FIG. It may also be applied to data forwarding.

[0080] (3.2.2) Example 2 8 shows an example of a part of a communication sequence using a new RRC message according to operation example 2. FIG. 8 also corresponds to the example of a communication sequence (late data forwarding) according to the conditional PSCell addition shown in FIG.

[0081] As shown in FIG. 8, UE 200 may embed an NR RRC Reconfiguration Complete in a new LTE RRC message (which may also be referred to as ConditionalReconfiguration).

[0082] At this time, the UE 200 may include identification information (gNB ID) of the gNB configuring the Target PSCell (T-SN) in the ConditionalReconfiguration. Also, the ConditionalReconfiguration may include a plurality of combinations (pairs) of RRC Reconfiguration and gNB ID.

[0083] Furthermore, instead of the gNB ID, the T-SN cell ID (such as CGI) may be included.

[0084] Note that although FIG. 8 also shows an example of late data forwarding, transmission of ConditionalReconfiguration including such ConditionalReconfiguration may also be applied to early data forwarding shown in FIG.

[0085] (3.2.3) Example 3 Next, in step 5 of the above-described operation example 1 (FIG. 7) and operation example 2 (FIG. 8), the MN may include a cell ID (CGI or the like) of the Target PSCell for each condReconfigId in ConditionalReconfiguration included in RRC Reconfiguration. The RRC layer of the UE 200 may be configured based on the RRC Reconfiguration including such a cell ID.

[0086] As described above, UE200 needs to apply the RRC reconfiguration of the target PSCell and send an RRC reconfiguration complete message to the SN via the MN. Therefore, the UE200 may encode the cell ID (NR PCI, NR CGI, or gNB ID) of the target PSCell that meets the conditions for addition or change in the LTE RRC layer and transmit the above-mentioned ULInformationTransferMRDC message or a new RRC message (bye-message) to the MN together with the RRC Reconfiguration Complete.

[0087] The MN (eNB100A) may identify a T-SN based on the cell ID (or gNB ID) of the Target PSCell included in the ULInformationTransferMRDC message or new RRC message (bye-message) transmitted from the UE200 and the frequency band in NR, and may send an SgNB Reconfiguration Complete to the identified T-SN.

[0088] Alternatively, the MN may identify the T-SN based on the PCI of the Target PSCell transmitted from the UE 200 and the frequency band in NR (which may be interpreted as a frequency band allocated to NR).

[0089] (3.3) Information elements and RRC message configuration examples Next, an example of the configuration of the above-mentioned information elements (IEs) of the RRC layer and the RRC message will be described.

[0090] 9 shows an example of the configuration of the IE CondReconfigToAddModList. The IE CondReconfigToAddModList is defined in 3GPP TS38.331, Chapter 6.3.2.

[0091] The IE CondReconfigToAddModList relates to the list of conditional reconfigurations to add or modify, and for each entry, the condReconfigId and the associated condExecutionCond and condRRCReconfig are used as shown in FIG.

[0092] CondReconfigToAddModList may be interpreted as a configuration list of candidate Special Cells (SpCells) to be added or modified for conditional handover (CHO) or CPC.

[0093] In this embodiment, a field for targetSecondaryNodeId (see underlined part) which is identification information of the T-SN may be included.

[0094] 10 shows an example of the structure of the NR ULInformationTransferMRDC message. The NR ULInformationTransferMRDC message is specified in 3GPP TS38.331, Chapter 6.2.2.

[0095] 10, the NR ULInformationTransferMRDC message may include ULInformationTransferMRDC-r17-IEs as an information element. As expressed as ULInformationTransferMRDC-r17-IEs, this IE may be supported in 3GPP Release-17, but may also be supported in other releases.

[0096] The ULInformationTransferMRDC-r17-IEs may include the fields of targetSecondaryNodeId and targetPSCellId (see the underlined parts). The targetPSCellId is identification information (such as CGI) of the Target PSCell.

[0097] 11 shows an example of the structure of an LTE ULInformationTransferMRDC message. The LTE ULInformationTransferMRDC message is specified in 3GPP TS36.331, Chapter 6.2.2.

[0098] As shown in Fig. 11, the configuration of the LTE ULInformationTransferMRDC message is generally similar to the configuration of the NR ULInformationTransferMRDC message shown in Fig. 10, and may include ULInformationTransferMRDC-r17-IEs. The ULInformationTransferMRDC-r17-IEs may include fields for targetSecondaryNodeId and targetPSCellId (see underlined parts).

[0099] (4) Actions and Effects According to the above-described embodiment, the following advantageous effects can be obtained: Specifically, the UE 200 can transmit a ULInformationTransferMRDC message (dual connectivity information) including an RRC Reconfiguration Complete (a radio resource control layer reconfiguration message) to the network in the conditional PSCell addition / change procedure.

[0100] Furthermore, in the procedure of conditional PSCell addition / change, the UE 200 can transmit another message of the RRC layer including RRC Reconfiguration Complete, for example, a new RRC message (bye-message), to the network.

[0101] Therefore, even when conditional PSCell addition / change is applied in a specific dual connectivity such as EN-DC, the UE 200 can add or change the PSCell using an RRC message that can be recognized by the MN (eNB).

[0102] That is, according to the wireless communication system 10, even when conditional PSCell addition / change is applied in dual connectivity such as EN-DC, it is possible to reliably perform addition / change of PSCell.

[0103] In this embodiment, the UE 200 can receive an RRC Reconfiguration (a message of the radio resource control layer) including an SCell (which may include a PSCell) or identification information (CGI or gNB ID) of a radio base station (gNB) that forms the SCell, and transmit a ULInformationTransferMRDC message including the CGI (or gNB ID) to the network. Alternatively, the UE 200 can transmit another message of the RRC layer including the CGI (or gNB ID), specifically, the above-mentioned new RRC message (bye-message), to the network.

[0104] Therefore, the MN (eNB 100A) can easily and accurately determine the Target PSCell (which may also be referred to as T-SN) in the conditional PSCell addition / change.

[0105] (5) Other embodiments The present invention has been described above with reference to the examples, but it will be obvious to those skilled in the art that the present invention is not limited to these examples and that various modifications and improvements are possible.

[0106] 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.

[0107] Also, if the MN is a gNB and the SN is a gNB (NR-DC), the UE 200 may apply RRC Reconfiguration, encode the cell ID (NR PCI, NR CGI or gNB ID) of the Target PSCell that meets the conditions for addition or change in the NR RRC layer, and incorporate it into the above-mentioned ULInformationTransferMRDC message or a new RRC message (bye-message) together with RRC Reconfiguration Complete and transmit it to the MN.

[0108] Alternatively, if the MN is a gNB and the SN is an eNB (NE-DC), the UE 200 may apply RRC Connection Reconfiguration, encode the cell ID (NR PCI, NR CGI or gNB ID) of the Target PSCell that meets the conditions for addition or change in the NR RRC layer, and incorporate it into the above-mentioned ULInformationTransferMRDC message or a new RRC message (bye-message) together with RRC Connection Reconfiguration Complete and transmit it to the MN.

[0109] Furthermore, in the above-described embodiments, the description has been given mainly using the example of conditional PSCell addition / change, but as described above, similar operations may also be applied to conditional inter-SN PSCell change procedures (MN-initiated conditional inter-SN PSCell change / SN-initiated conditional inter-SN PSCell change).

[0110] 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 at least one of hardware and software. Furthermore, the method of 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 connected directly or indirectly (for example, by wire, wirelessly, etc.) and these multiple devices. The functional block may also be realized by combining the single device or multiple devices with software.

[0111] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, 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.

[0112] 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. 12 is a diagram showing an example of the hardware configuration of the devices. As shown in Fig. 12, 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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, a register, and the like.

[0117] 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-mentioned embodiments. Furthermore, the various processes described above may be executed by one 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.

[0118] The memory 1002 is a computer-readable recording medium and may be configured by, for example, at least one of 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 can store a program (program code), a software module, etc., that can execute a method according to an embodiment of the present disclosure.

[0119] 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 appropriate medium including at least one of memory 1002 and storage 1003.

[0120] 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.

[0121] 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).

[0122] The input device 1005 is an input device (for example, 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 (for example, a display, a speaker, an LED lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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 extended 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.

[0127] 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.

[0128] 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 (for example, an MME or an 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 (for example, an MME and an S-GW) may also be used.

[0129] 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 / output via multiple network nodes.

[0130] The input and output information may be stored in a specific location (for example, memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be sent to another device.

[0131] 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).

[0132] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, notification of predetermined information (e.g., notification that "X is true") is not limited to being done explicitly, but may be done implicitly (e.g., by not notifying the predetermined information).

[0133] 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.

[0134] 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.

[0135] 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.

[0136] Note that terms explained 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.

[0137] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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)).

[0142] 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.

[0143] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0144] 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.

[0145] At least one of the base station and the mobile station may be called 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, or the mobile object itself. 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.

[0146] 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 communication between terminals (for example, "side"). For example, terms such as uplink channel and downlink channel may be read as side channel.

[0147] 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.

[0148] A radio frame may consist of one or more frames in the time domain.

[0149] Each of the one or more frames in the time domain may be called a subframe, and a subframe may further be made up of one or more slots in the time domain.

[0150] A subframe may be of a fixed time length (eg, 1 ms) that is independent of numerology.

[0151] Numerology may be a communication parameter applied to at least one of transmission and 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 a transceiver in the frequency domain, and specific windowing operations performed by a transceiver in the time domain.

[0152] 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.

[0153] A slot may include multiple minislots. Each minislot may consist of one or more 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.

[0154] 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.

[0155] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called 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.

[0156] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) to each user terminal in TTI units. However, the definition of TTI is not limited to this.

[0157] 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.

[0158] 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. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0159] A TTI having a time length of 1 ms may be called 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 called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] The time domain of an RB may include one or more symbols and may be one slot, one minislot, one subframe, or one TTI in length. Each TTI, subframe, etc. may be composed of one or more resource blocks.

[0164] 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, or the like.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0169] 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 can be changed in various ways.

[0170] 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.

[0171] The reference signal may also be abbreviated as Reference Signal (RS), and may also be called a pilot depending on the applicable standard.

[0172] 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."

[0173] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0174] 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.

[0175] When used in this disclosure, the terms "include," "including," and variations thereof are intended to be inclusive, similar to the term "comprising." Furthermore, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0176] 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.

[0177] 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.

[0178] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." Note that 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."

[0179] 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. [Explanation of symbols]

[0180] 10. Wireless communication systems 20 E-UTRAN 30 NG RAN 100A eNB 100B gNB 110 Radio Communication Department 120 RRC processing unit 130 DC processing section 140 Control Unit 200 UE 210 Radio Communication Department 220 RRC processing unit 230 DC processing section 240 Control Unit 1001 processor 1002 memory 1003 Storage 1004 Communication equipment 1005 Input Device 1006 Output Device 1007 Bus

Claims

1. a receiving unit that receives a first message from a master node, the first message including a radio resource reconfiguration message related to the addition or change of a secondary node; a transmitter configured to transmit a second message including a radio resource reconfiguration completion message regarding the addition or change of the secondary node to the master node; The first message includes, for each radio resource reconfiguration, identification information of the secondary node that is a candidate for addition or change; The second message is a terminal including identification information of a secondary node that has applied radio resource reconfiguration and the radio resource reconfiguration completion message corresponding to the identification information.

2. receiving a first message from a master node, the first message including a radio resource reconfiguration message related to the addition or modification of a secondary node; transmitting a second message to the master node, the second message including a radio resource reconfiguration completion message regarding the addition or change of the secondary node; The first message includes, for each radio resource reconfiguration, identification information of the secondary node that is a candidate for addition or change; A wireless communication method for a terminal, wherein the second message includes identification information of a secondary node to which wireless resource reconfiguration has been applied and the wireless resource reconfiguration completion message corresponding to the identification information.

3. a transmitter configured to transmit a first message including a radio resource reconfiguration message regarding addition or change of a secondary node to a terminal; a receiving unit that receives a second message from the terminal, the second message including a radio resource reconfiguration completion message related to the addition or change of the secondary node; The first message includes, for each radio resource reconfiguration, identification information of the secondary node that is a candidate for addition or change; The radio base station, in the second message, includes identification information of a secondary node to which the terminal has applied the radio resource reconfiguration and the radio resource reconfiguration completion message corresponding to the identification information.

4. A wireless communication system including a wireless base station and a terminal, The radio base station a transmitter configured to transmit a first message including a radio resource reconfiguration message regarding addition or change of a secondary node to the terminal; a receiving unit that receives a second message from the terminal, the second message including a radio resource reconfiguration completion message related to the addition or change of the secondary node; The first message includes, for each radio resource reconfiguration, identification information of the secondary node that is a candidate for addition or change; The terminal a receiving unit that receives the first message from the radio base station; a transmitting unit that transmits the second message to the radio base station; A wireless communication system, wherein the second message includes identification information of a secondary node to which the terminal has applied radio resource reconfiguration and the radio resource reconfiguration completion message corresponding to the identification information.

Images