Communication node, wireless communication system and wireless communication method

Abstract

The terminal comprises: a control unit which, when a cell included in the second cell group is changed in a dual connection using a first cell group and a second cell group, sets an information element related to the cell before the change as a variable; and a sending unit which sends a message including the information element set as the variable to a network.

Description

Technical Field

[0001] The present disclosure relates to a terminal and a base station for appropriately collecting the movement history of a UE on the SN side. Background Art

[0002] The 3rd Generation Partnership Project (3GPP) has standardized the fifth-generation mobile communication system (also called 5G, New Radio (NR) or Next Generation (NG)), and has also promoted the standardization of the next generation called Beyond 5G, 5G Evolution or 6G.

[0003] 3GPP supports dual connectivity (MR-DC (Multi-RAT Dual Connectivity)) using the first cell group (MCG (Master Cell Group)) and the second cell group (SCG (Secondary Cell Group)). MR-DC includes EN-DC (E-UTRA-NR Dual Connectivity), NE-DC (NR-EUTRA Dual Connectivity), and NR-DC (NR-NR Dual Connectivity).

[0004] In addition, for the purpose of SON (Self Organizing Network) and MDT (Minimization of Drive Test), data collection of UE (User Equipment) history information in EN-DC has been studied (for example, Non-Patent Document 1).

[0005] Prior art literature

[0006] Non-patent literature

[0007] Non-patent document 1: "New WID on enhancement of data collection for SON / MDT inNR", RP-201281, 3GPP TSG RAN Meeting #86-e, 3GPP, July 2020 Summary of the invention

[0008] In the above background, the inventors and the like conducted in-depth research and as a result, found it necessary to collect the movement history of a UE on the SN (Secondary Node) side having an SCG.

[0009] Accordingly, the following disclosure has been completed in view of the above circumstances, and an object thereof is to provide a radio base station and a terminal capable of appropriately collecting the movement history of a UE on the SN side.

[0010] One aspect of the present disclosure provides a terminal having: a control unit that sets an information element related to a cell before change as a variable when a cell included in the second cell group is changed in dual connectivity using a first cell group and a second cell group; and a transmission unit that transmits a message including the information element set as the variable to a network.

[0011] One aspect of the present disclosure provides a base station having: a transmission unit that, when managing either the first cell group or the second cell group in dual connectivity using the first cell group and the second cell group, transmits a message including an information element indicating a change history of a cell included in the second cell group to a node that manages the other of the first cell group and the second cell group.

[0012] One aspect of the present disclosure provides a communication node that manages the second cell group in dual connectivity using a first cell group and a second cell group, wherein the communication node has:

[0013] a reception unit that receives from a terminal a message including an information element that is an information element related to a cell before change set as a variable by the terminal when a cell included in the second cell group is changed; and

[0014] a transmission unit that transmits a message including an information element indicating a change history of a cell included in the second cell group to another communication node that manages the first cell group,

[0015] the transmission unit transmits, as a response to a message requesting at least any one of release and correction of a cell included in the second cell group, a message including an information element indicating a change history of a cell included in the second cell group to the other communication node, or

[0016] the transmission unit transmits, as a message requesting at least any one of release, change, and correction of a cell included in the second cell group, a message including an information element indicating a change history of a cell included in the second cell group to the other communication node.

[0017] One embodiment of the present disclosure provides a wireless communication system having a terminal and a communication node, wherein the communication node manages the second cell group in a dual connection using a first cell group and a second cell group, wherein:

[0018] The terminal has:

[0019] a control unit that, in the dual connectivity, sets, when a cell included in the second cell group is changed, an information element related to the cell before the change as a variable; and

[0020] a sending unit configured to send a message including the information element set as the variable to a network,

[0021] The communication node has:

[0022] a receiving unit configured to receive, from the terminal, a message including the information element set as the variable; and

[0023] a sending unit that sends a message including an information element indicating a change history of cells included in the second cell group to other communication nodes that manage the first cell group,

[0024] The sending unit of the communication node sends a message including an information element indicating a change history of the cells included in the second cell group to the other communication node as a response to a message requesting at least one of release and modification of the cells included in the second cell group, or,

[0025] The sending unit of the communication node sends a message including an information element indicating a change history of the cells included in the second cell group to the other communication node as a message requesting at least any one of release, change and correction of the cells included in the second cell group.

[0026] One embodiment of the present disclosure provides a wireless communication method, wherein the wireless communication method comprises the following steps:

[0027] Step A, a communication node that manages the second cell group in a dual connection using a first cell group and a second cell group receives a message including the following information element from a terminal, wherein the information element is an information element related to a cell before the change and is set as a variable by the terminal when a cell included in the second cell group is changed; and

[0028] Step B, the communication node sends a message including an information element indicating a change history of cells included in the second cell group to other communication nodes managing the first cell group,

[0029] The step B comprises the following steps:

[0030] sending, to the other communication node, a message including an information element indicating a change history of cells included in the second cell group as a response to a message requesting at least one of release and modification of cells included in the second cell group, or

[0031] A message including an information element indicating a change history of cells included in the second cell group is sent to the other communication node as a message requesting at least any one of release, change and correction of the cells included in the second cell group. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a diagram schematically showing the overall structure of the wireless communication system 10 .

[0033] Figure 2 is a functional block diagram of UE 200.

[0034] Figure 3 This is a diagram for explaining a usage scenario.

[0035] Figure 4 This is a timing chart showing operation example 1.

[0036] Figure 5 This is a diagram showing an example of UEInformationResponse (ASN.1 format).

[0037] Figure 6 This is a diagram showing an example of VisitedCellInfoListNR (ASN.1 format).

[0038] Figure 7 This is a timing chart showing operation example 2.

[0039] Figure 8 This is a diagram showing an example of UEAssistanceInformation (ASN.1 format).

[0040] Fig. 9 This is a timing chart showing operation example 3.

[0041] Fig.10 This is a diagram showing an example of ULInformationTransferMRDC (ASN.1 format).

[0042] Fig.11 This is a timing chart showing operation example 4.

[0043] Fig.12This is a diagram showing an example of VisitedCellInfoListEN-DC (ASN.1 format).

[0044] Fig.13 This is a diagram showing an example of VisitedCellInfoListEN-DC (ASN.1 format).

[0045] Fig.14 This is a sequence diagram showing an operation example according to Modification Example 2.

[0046] Fig.15 This is a sequence diagram showing an operation example according to Modification Example 2.

[0047] Fig.16 This is a sequence diagram showing an operation example according to Modification Example 2.

[0048] Fig.17 This is a diagram showing an example of the hardware configuration of the UE 200 . DETAILED DESCRIPTION

[0049] Hereinafter, the embodiments will be described based on the drawings. In addition, the same or similar reference numerals are given to the same functions and structures, and the description thereof will be appropriately omitted.

[0050] (1) Overall schematic structure of wireless communication system

[0051] Figure 1 1 is a schematic diagram of the overall structure of the wireless communication system 10 involved in the implementation method. The wireless communication system 10 is a wireless communication system that complies with Long Term Evolution (LTE) and 5G New Radio (NR). In addition, LTE can also be called 4G, and NR can also be called 5G.

[0052] In addition, LTE and NR may be interpreted as radio access technologies (RATs). In an embodiment, LTE may be referred to as a first radio access technology and NR may be referred to as a second radio access technology.

[0053] 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). In addition, the wireless communication system 10 includes a terminal 200 (hereinafter referred to as UE 200, User Equipment).

[0054] The E-UTRAN 20 includes an eNB 100A which is a base station conforming to LTE. The NG RAN 30 includes a gNB 100B which is a base station conforming to 5G (NR).

[0055] eNB 100A, gNB 100B and UE 200 are capable of supporting carrier aggregation (CA) using multiple component carriers (CCs) and dual connection (DC) in which the UE communicates with multiple nodes simultaneously.

[0056] The E-UTRAN 20 is connected to the core network 40 for LTE. In addition, the E-UTRAN 20, the NG RAN 30, and the core network 40 may be simply referred to as a network.

[0057] A management server 50 (hereinafter referred to as an OAM server 50; Operation Administration and Management server: operation, maintenance and management server) may be provided in the core network 40. The OAM server 50 may execute processes related to SON (Self Organizing Network), MDT (Minimization of Drive Test) and the like.

[0058] The eNB 100A and the gNB 100B are capable of forming an area (which may be expressed as a cell) in which wireless communications with the UE 200 can be performed, specifically, area A1 or area A2.

[0059] Among them, area A1 can be interpreted as an area where UE 200 can communicate with eNB 100A. Area A2 can be interpreted as an area where UE 200 can communicate with gNB 100B. Area A1 and area A2 can overlap with each other. In the area where area A1 and area A2 overlap, UE 200 can perform EN-DC (E-UTRA-NR Dual Connectivity) or NE-DC (NR-EUTRA Dual Connectivity) that can communicate with eNB 100A and gNB 100B at the same time. In addition, in Figure 2 In the example, the case where the base station capable of communicating with the UE 200 in area A1 is the eNB 100A is illustrated, but the base station capable of communicating with the UE 200 in area A1 may also be the gNB 100B provided in the NG RAN 30. In this case, NR-DC (NR-NR Dual Connectivity) in which the UE 200 communicates with two or more gNBs 100B (or cells) simultaneously can be performed.

[0060] Among them, the group of cells that can perform processing related to C-plane (control plane) and U-plane (user plane) in the above-mentioned DC can be called the first cell group (MCG; Master Cell Group). The group of cells that can perform processing related to U-plane (user plane) in the above-mentioned DC can be called the second cell group (SCG; Secondary Cell Group). For example, in the above-mentioned EN-DC, eNB 100A can be called MN (Master Node), and gNB 100B can be called SN (Secondary Node). In the above-mentioned NE-DC, eNB 100A can be called SN, and gNB 100B can be called MN.

[0061] EN-DC, NE-DC and NR-DC may be collectively referred to as MR (Multi-RAT)-DC hereinafter.

[0062] (2) Functional block structure of wireless communication system

[0063] Next, a functional block configuration of the wireless communication system 10 will be described. Specifically, a functional block configuration of the UE 200 will be described.

[0064] Figure 2 is a functional block diagram of UE 200. Figure 2 As shown, UE 200 includes a radio signal transceiver 210 , an amplifier 220 , a modulation and demodulation unit 230 , a control signal and reference signal processing unit 240 , an encoding and decoding unit 250 , a data transceiver 260 , and a control unit 270 .

[0065] The wireless signal transceiver 210 transmits and receives wireless signals based on LTE or NR. The wireless signal transceiver 210 supports Massive MIMO, CA using multiple CCs in a bundled manner, DC, and the like.

[0066] The amplifier unit 220 is composed of a PA (Power Amplifier) / LNA (Low Noise Amplifier) ​​etc. The amplifier unit 220 amplifies the signal output from the modulation and demodulation unit 230 to a predetermined power level. In addition, the amplifier unit 220 amplifies the RF signal output from the wireless signal transmission and reception unit 210 .

[0067] The modem unit 230 performs data modulation / demodulation, transmission power setting, resource block allocation, etc. according to each predetermined communication destination (eNB 100A or gNB 100B). In the modem unit 230, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) / Discrete Fourier Transform-Spread (DFT-S-OFDM) can be applied. In addition, DFT-S-OFDM can be used not only for uplink (UL) but also for downlink (DL).

[0068] The control signal / reference signal processing unit 240 performs processing related to various control signals transmitted and received by the UE 200 and processing related to various reference signals transmitted and received by the UE 200 .

[0069] Specifically, the control signal / reference signal processing unit 240 is capable of receiving various control signals (e.g., control signals of the radio resource control layer (RRC)) sent from the eNB 100A or gNB 100B via a predetermined control channel. In addition, the control signal / reference signal processing unit 240 sends various control signals toward the eNB 100A or gNB 100B via a predetermined control channel.

[0070] The control signal / reference signal processing unit 240 performs processing using reference signals (RS) such as a demodulation reference signal (DMRS) and a phase tracking reference signal (PTRS).

[0071] DMRS is a terminal-specific reference signal (pilot signal) known between the base station and the terminal for estimating a fading channel used for data demodulation. PTRS is a terminal-specific reference signal for estimating phase noise, which is a problem in high frequency bands.

[0072] In addition, in addition to DMRS and PTRS, reference signals also include a channel state information-reference signal (CSI-RS), a sounding reference signal (SRS), and a positioning reference signal (PRS) for position information.

[0073] In addition, the channels include control channels and data channels. The control channels include PDCCH (Physical Downlink Control Channel), PUCCH (Physical Uplink Control Channel), RACH (Random Access Channel, Downlink Control Information (DCI) including the Random Access Radio Network Temporary Identifier (RA-RNTI)), and Physical Broadcast Channel (PBCH).

[0074] In addition, data channels include PDSCH (Physical Downlink Shared Channel), PUSCH (Physical Uplink Shared Channel), etc. Data refers to data transmitted via the data channel. The data channel may also be replaced by a shared channel.

[0075] Among them, the control signal and reference signal processing unit 240 receives downlink control information (DCI). DCI includes fields storing DCI formats (DCI Formats), carrier indicator (CI), BWP indicator (BWPindicator), FDRA (Frequency Domain Resource Allocation), TDRA (Time Domain Resource Allocation), MCS (Modulation and Coding Scheme), HPN (HARQ Process Number), NDI (New Data Indicator), RV (Redundancy Version), etc., as existing fields.

[0076] The value stored in the DCI Format field is an information element that specifies the format of the DCI. The value stored in the CI field is an information element that specifies the CC to which the DCI is applied. The value stored in the BWP indicator field is an information element that specifies the BWP to which the DCI is applied. The BWP that can be specified by the BWPindicator is set by the information element (BandWidthPart-Config) contained in the RRC message. The value stored in the FDRA field is an information element that specifies the frequency domain resources to which the DCI is applied. The frequency domain resources are determined by the value stored in the FDRA field and the information element (RA Type) contained in the RRC message. The value stored in the TDRA field is an information element that specifies the time domain resources to which the DCI is applied. The time domain resources are determined by the value stored in the TDRA field and the information element (pdsch-TimeDomainAllocationList) contained in the RRC message. The time domain resources can also be determined by the value stored in the TDRA field and the default table. The value stored in the MCS field is an information element that specifies the MCS to which the DCI is applied. The MCS is determined by the value stored in the MCS and the MCS table. The MCS table can be specified by an RRC message or determined by RNTI scrambling. The value stored in the HPN field is an information element that specifies the HARQ Process to which the DCI is applied. The value stored in the NDI field is an information element that is used to determine whether the data to which the DCI is applied is the first transmitted data. The value stored in the RV field is an information element that specifies the redundancy of the data to which the DCI is applied.

[0077] In an embodiment, the control signal / reference signal processing unit 240 constitutes a sending unit that sends a message including an information element set as a variable. The variable is a variable in which, when a cell (e.g., PSCell (Primary-Secondary Cell)) included in the SCG in the MR-DC is changed, an information element related to the PSCell before the change is set. The variable may be referred to as varMobilityHistoryReport. The variable may also be referred to as visitedCellInfoList included in varMobilityHistoryReport. The message including the visitedCellInfoList may be an RRC message. The message including the visitedCellInfoList may include a UEInformationResponse sent according to a UEInformationRequest. The message including the visitedCellInfoList may include UEAssistanceInformation sent autonomously by the UE 200.

[0078] The encoding / decoding unit 250 performs data segmentation / concatenation and channel coding / decoding, etc. according to each predetermined communication destination (eNB 100A or gNB 100B).

[0079] Specifically, the encoding / decoding unit 250 divides the data output from the data transceiver unit 260 into predetermined sizes and performs channel coding on the divided data. In addition, the encoding / decoding unit 250 decodes the data output from the modulation / demodulation unit 230 and concatenates the decoded data.

[0080] The data transceiver 260 performs transmission and reception of protocol data units (PDU) and service data units (SDU). Specifically, the data transceiver 260 performs assembly / disassembly of PDU / SDU in multiple layers (such as the medium access control layer (MAC), the radio link control layer (RLC), and the packet data convergence protocol layer (PDCP)). In addition, the data transceiver 260 performs error correction and retransmission control of data according to hybrid ARQ (Hybrid automatic repeat request).

[0081] The control unit 270 controls each functional block constituting the UE 200. In an embodiment, the control unit 270 constitutes a control unit that sets the information element related to the PSCell before the change as a variable when the cell (e.g., PSCell (Primary-Secondary Cell)) included in the SCG in the MR-DC is changed. As described above, the variable can be called varMobilityHistoryReport or visitedCellInfoList.

[0082] (3) Application scenarios

[0083] The following describes an application scenario of the embodiment. In the application scenario, a case where a change of the PSCell is performed in the MR-DC in which the UE 200 communicates with the MN 300 and the SN 400 is described. Figure 3MN 300A and MN 300B are exemplified as MN 300, and SN 400A to SN400F are exemplified as SN 400. MC1 and MC2 are exemplified as cells of MN 300, and SC1 to SC6 are exemplified as cells of SN 400. For example, the coverage area of ​​SC1 to SC3 overlaps with the coverage area of ​​MC1, and the coverage area of ​​SC4 to SC6 overlaps with the coverage area of ​​MC2. In this case, MC1 and MC2 are cells that can be used as PCell (Primary Cell), and SC1 to SC6 are cells that can be used as PSCell.

[0084] Under this premise, the case where UE 200 moves from SC1 to SC3 is considered. For example, when MC1 is used as PCell, PSCell can be changed from SC1 to SC2. In addition, when MC1 is used as PCell, PSCell can also be changed from SC2 to SC3.

[0085] In this case, when the PSCell is changed from SC1 to SC2, UE 200 sets the information element related to SC1 before the change to visitedCellInfoList. In addition, when the PSCell is changed from SC2 to SC3, UE 200 may set the information element related to SC2 before the change to visitedCellInfoList. The information element related to the cell may include a CGI (Cell Global Identify) that uniquely identifies the cell in the wireless communication system 10. The information element related to the cell may also include a PCI (Physical Cell Identify) that uniquely identifies the cell in the SN 400. The information element related to the cell may also include an ARFCN (Absolute Radio-Frequency Channel Number) that identifies the frequency of the cell.

[0086] In addition, UE 200 sends a message including visitedCellInfoList to the network. UE 200 may also send a message including visitedCellInfoList to MN 300. UE 200 may send a message including visitedCellInfoList to SN 400 via MN 300. UE 200 may also send a message including visitedCellInfoList to SN 400 without going through MN 300.

[0087] (4) Action example

[0088] The following is an explanation of an example of an operation of the implementation method. The following illustrates a case where EN-DC is performed as MR-DC. That is, an example is given where the eNB 100A included in the E-UTRAN 20 is the MN 300 and the gNB 100B included in the NG RAN 30 is the SN 400. However, the implementation method is not limited to this. MR-DC can be either NE-DC or NR-DC.

[0089] (4.1) Action Example 1

[0090] The following describes a case where a message including visitedCellInfoList is sent to the MN 300. Figure 4 This is a timing chart showing operation example 1.

[0091] like Figure 4 As shown, in step S10, UE 200 detects a change of a PSCell included in an SCG in EN-DC.

[0092] In step S11, UE 200 sets the information element related to the PSCell before the change to visitedCellInfoList.

[0093] In step S12, UE 200 receives UEInformationRequest from MN 300. UEInformationRequest may include an information element explicitly requesting visitedCellInfoList. UEInformationRequest may also include an information element explicitly requesting mobilityHistoryReport or mobilityHistoryReportOfPScell.

[0094] In step S13, UE 200 sends UEInformationResponse to MN 300. UEInformationResponse includes visitedCellInfoList in which information elements related to the PSCell before the change are set. When the PSCell is changed twice or more, visitedCellInfoList may include two or more information elements related to the PSCell before the change.

[0095] Furthermore, in the action example 1, in order to notify the MN 300 of the visitedCellInfoList, in step S13, the visitedCellInfoList is encoded as an information element related to the E-UTRAN 20.

[0096] like Figure 5 As shown, UEInformationResponse may include UEInformationResponse-r17-IEs. UEInformationResponse-r17-IE may include mobilityHistoryReportNR-r17. MobilityHistoryReportNR-r17 may include VisitedCellInfoListNR-r17. In addition, mobilityHistoryReportNR-r17 may be an example of an information element indicating a change history of a PSCell included in an SCG.

[0097] like Figure 6 As shown, VisitedCellInfoListNR (VisitedCellInfoListNR-r17) may include visitedCellInfoNR-r17 (i.e., information elements related to the PSCell before the change). It may also include visitedCellInfoNR-r17 (i.e., identification information of the PSCell before the change). visitedCellID-r17 may include cgi-Info-r17 (i.e., CGI of the PSCell) and may also include pci-arfcn-r17 (i.e., PCI and ARFCN of the PSCell).

[0098] Among them, visitedCellInfoNR-r17 may include an information element (timeSpentNR-r17) indicating the time that UE 200 stayed in the PSCell before the change.

[0099] Note that, in Action Example 1, a case where visitedCellInfoListNR is sent to MN 300 (eNB 100A) in EN-DC is illustrated. Figure 5 and Figure 6 Messages and information elements related to E-UTRAN 20 are illustrated in FIG.

[0100] (4.2) Action Example 2

[0101] The following describes a case where a message including visitedCellInfoList is sent to SN 400 via MN 300. Figure 7 This is a timing chart showing operation example 2.

[0102] like Figure 7 As shown, in step S20, UE 200 detects a change of the PSCell included in the SCG in EN-DC.

[0103] In step S21, UE 200 sets the information element related to the PSCell before the change to visitedCellInfoList.

[0104] In step S22, ULInformationTransferMRDC is sent to MN 300. ULInformationTransferMRDC includes UEAssistanceInformation, and UEAssistanceInformation includes visitedCellInfoList in which information elements related to the PSCell before the change are set. When the PSCell is changed twice or more, visitedCellInfoList may include two or more information elements related to the PSCell before the change.

[0105] Furthermore, in Action Example 2, in order to transparently notify the SN 400 of the visitedCellInfoList, in step S22, the visitedCellInfoList is encoded as an information element related to the NG RAN 30.

[0106] In step S23, MN 300 sends RRC Transfer to SN 400. RRC Transfer includes visitedCellInfoList included in UEAssistanceInformation.

[0107] As described below, ULInformationTransferMRDC includes ul-DCCH-MessageNR. ul-DCCH-MessageNR is an information element used for forwarding RRC messages related to NG RAN 30. The RRC messages related to NG RAN 30 include UEAssistanceInformation (see Fig.10 ).

[0108] like Figure 8As shown, UEAssistanceInformation may include UEAssistanceInformation-r17-IEs. UEAssistanceInformation-r17-IEs may include mobilityHistoryReport-r17. mobilityHistoryReport-r17 may include mobilityHistoryReport-r16. mobilityHistoryReport-r16 may include VisitedCellInfoList-r16. In addition, mobilityHistoryReport-r17 may be an example of an information element representing the change history of the PSCell included in the SCG. In addition, similar to VisitedCellInfoListNR-r17, VisitedCellInfoList-r16 may include the CGI, PCI, and ARFCN of the PSCell before the change. VisitedCellInfoList-r16 may include an information element (timeSpent) representing the time that UE 200 stayed in the PSCell before the change.

[0109] Here, it should be noted that in Action Example 2, the case where visitedCellInfoList is transparently sent to SN 400 (gNB 100B) in EN-DC is illustrated, so Figure 8 Messages related to NG RAN 30 are illustrated in FIG.

[0110] (4.3) Action Example 3

[0111] The following describes a case where a message including visitedCellInfoList is sent to SN 400 via MN 300. Fig. 9 This is a timing chart showing operation example 3.

[0112] like Fig. 9 As shown, in step S30, UE 200 detects a change of the PSCell included in the SCG in EN-DC.

[0113] In step S31, UE 200 sets the information element related to the PSCell before the change to visitedCellInfoList.

[0114] In step S32, MN 300 receives RRC Transfer from SN 400. RRC Transfer includes UEInformationRequest, and UEInformationRequest may include an information element explicitly requesting visitedCellInfoList. UEInformationRequest may include an information element explicitly requesting mobilityHistoryReport or mobilityHistoryReportOfPScell.

[0115] In step S33, MN 300 sends DLInformationTransferMRDC to UE 200. DLInformationTransferMRDC includes UEInformationRequest included in RRC Transfer.

[0116] In step S34, UE 200 sends ULInformationTransferMRDC to MN 300. ULInformationTransferMRDC includes UEInformationResponse, and UEInformationResponse includes visitedCellInfoList in which information elements related to the PSCell before the change are set. When the PSCell is changed twice or more, visitedCellInfoList may include two or more information elements related to the PSCell before the change.

[0117] Furthermore, in Action Example 3, in order to transparently notify the SN 400 of the visitedCellInfoList, in step S33 , the visitedCellInfoList is encoded as an information element related to the NG RAN 30 .

[0118] In step S35, MN 300 sends RRC Transfer to SN 400. RRC Transfer includes visitedCellInfoList included in UEInformationResponse.

[0119] like Fig.10As shown, ULInformationTransferMRDC includes ul-DCCH-MessageNR. ul-DCCH-MessageNR is an information element used for forwarding an RRC message related to the NG RAN 30, and the RRC message related to the NG RAN 30 includes UEInformationResponse.

[0120] It should be noted that in action example 3, the case where the MN 300 (eNB 100A) receives ULInformationTransferMRDC in EN-DC is illustrated. Fig.10 Messages related to the E-UTRAN 20 are illustrated in FIG.

[0121] (4.4) Action Example 4

[0122] The following describes a case where a message including visitedCellInfoList is sent to SN 400 without passing through MN 300. Fig.11 is a timing diagram showing operation example 4. Fig.11 In the example, the case where SRB3 is configured in UE 200 is listed. SRB3 is an SRB (Signaling Radio Bearer) used to directly send NR-related measurement reports (RRC Measurement Report) from UE 200 to SN 400 (gNB 100B) in EN-DC.

[0123] like Fig.11 As shown, in step S40, UE 200 detects a change of the PSCell included in the SCG in EN-DC.

[0124] In step S41, UE 200 sets the information element related to the PSCell before the change to visitedCellInfoList.

[0125] In step S42, UEAssistanceInformation is directly sent to SN 400. UEAssistanceInformation includes visitedCellInfoList in which information elements related to the PSCell before the change are set. When the PSCell is changed twice or more, visitedCellInfoList may include two or more information elements related to the PSCell before the change.

[0126] In addition, in action example 4, visitedCellInfoList is directly notified to the SN 400 , and therefore in step S42 , visitedCellInfoList is encoded as an information element related to the NG RAN 30 .

[0127] (5) Action and Effect

[0128] In the embodiment, when the PSCell is changed, the UE 200 sets the information element related to the PSCell before the change as a variable (visitedCellInfoList), and sends a message including the information element (CGI of the PSCell, PCI of the PSCell, ARFCN of the PSCell, timeSpent, etc.) set as a variable to the network (MN 300 or SN 400). According to this structure, the network (MN 300 or SN 400) can grasp the change history of the PSCell in the MR-DC (in other words, the movement history of the UE 200), and can appropriately set the mobility parameter related to the SN 400. For example, the mobility parameter related to the SN 400 is a threshold value for comparison with the reception quality (RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality)) in order to determine the change of the PSCell.

[0129] For example, regarding Event A3 (§5.5.4.4 “Neighbour becomes offsetbetter than SpCell” of TS38.331 V16.1.0), the mobility parameter may include TimeToTrigger, a3-offset, hysteresis, etc. Regarding Event A5 (§5.5.4.6 “SpCell becomes worsethan threshold1 and neighbor becomes better than threshold2” of TS38.331 V16.1.0), the mobility parameter may include TimeToTrigger, a5-Threshold1, a5-Threshold2, hysteresis, etc. Regarding Event B1-NR (§5.5.4.8 “Inter RAT neighbor becomes betterthan threshold” of TS38.331 V16.1.0), the mobility parameter may include TimeToTrigger, b1-ThresholdNR, hysteresis, etc. Regarding Event B2-NR (§5.5.4.9 “PCell becomes worse than threshold1 and inter RAT neighbor becomes better than threshold2” of TS38.331 V16.1.0), the mobility parameter may include TimeToTrigger, b2-Threshold1, b2-Threshold2NR, hysteresis, etc.

[0130] In particular, in EN-DC, eNB 100A (MN 300) can grasp the change history of PSCell on the NR side, so eNB 100A (MN 300) can appropriately set the mobility parameter related to SN 400 on the NR side (for example, the above-mentioned action example 1). gNB 100B (SN 400) can grasp the change history of PSCell on the NR side, so gNB 100B (SN400) can appropriately set the mobility parameter related to SN 400 on the NR side (for example, the above-mentioned action examples 2 to 4).

[0131] [Change Example 1]

[0132] A modification example 1 of the embodiment will be described below. The differences from the embodiment will be mainly described below.

[0133] In the embodiment, the information element related to the PSCell before the change is set as a variable. In contrast, in Modification Example 1, UE 200 associates "the information element related to the PSCell used in MR-DC" and "the information element related to the PCell used in MR-DC" and sets them as variables. In other words, UE 200 associates the information element related to the PSCell before the change with the information element related to the PCell and sends a message to the network.

[0134] The variable used in Action Example 1 can be called VisitedCellInfoListEN-DC. Fig.12 As shown, VisitedCellInfoListEN-DC (VisitedCellInfoListEN-DC-r17) may include information elements related to the PCell used in EN-DC (visitedCellIdEUTRA-r17) and information elements related to the PSCell used in EN-DC (visitedCellInfoNR-r17).

[0135] The information element related to PCell (visitedCellIdEUTRA-r17) may include at least one of the CGI (cellGlobalId-r12) of PCell and the PCI / ARFCN (pci-arfcn-r12) of PCell. The information element related to PSCell (visitedCellInfoNR-r17) may include at least one of the CGI (cgi-Info) of PSCell and the PCI / ARFCN (pci-arfcn-r17) of PSCell.

[0136] In addition, VisitedCellInfoListEN-DC may include an information element (timeSpentEN-DC-r17) indicating the time that the UE 200 stays in the cells (PCell and PSCell) of EN-DC.

[0137] Note that, in Action Example 1, a case where visitedCellInfoList is sent to MN 300 (eNB 100A) in EN-DC is illustrated. Fig.12 Information elements related to the E-UTRAN 20 are exemplified in FIG.

[0138] The variable used in any one of Action Examples 2 to 4 may be called VisitedCellInfoListEN-DC. Fig.13 As shown, VisitedCellInfoListEN-DC (VisitedCellInfoListEN-DC-r17) may include information elements related to the PSCell used in EN-DC (nr-CellId-r16) and information elements related to the PCell used in EN-DC (eutra-CellId-r16).

[0139] The information element related to PSCell (nr-CellId-r16) may include at least one of the CGI (cgi-Info) of PSCell and the PCI / ARFCN (pci-arfcn-r16) of PSCell. The information element related to PCell (eutra-CellId-r16) may include at least one of the CGI (cgi-Info) of PCell and the PCI / ARFCN (pci-arfcn-r16) of PCell.

[0140] In addition, VisitedCellInfoListEN-DC may include an information element (timeSpentEN-DC-r17) indicating the time that the UE 200 stays in the cells (PCell and PSCell) of EN-DC.

[0141] In addition, it should be noted that in Action Examples 2 to 4, examples are given for transparently or directly sending visitedCellInfoList to SN 400 (gNB 100B) in EN-DC. Fig.13 Information elements related to NG RAN 30 are illustrated in FIG.

[0142] In Modification Example 1, UE 200 associates "information elements related to the PSCell before the modification" and "information elements related to the PCell" and sends a message to the network (MN 300 or SN 400). According to this structure, the network (MN 300 or SN 400) can grasp the PSCell in the MR-DC by using the relationship with the PCell, and can further appropriately grasp the movement history of UE 200.

[0143] [Change Example 2]

[0144] A modification example 2 of the embodiment will be described below. The differences from the embodiment will be mainly described below.

[0145] In modification example 2, the base station has a sending unit that, when managing either MCG or SCG in MR-DC, sends a message including a change history (e.g., MobilityHistoryReport) of a cell (PSCell) included in the SCG to a node managing the other of the MCG and SCG. MobilityHistoryReport includes an information element (hereinafter referred to as visitedCellInfoList(SN)) related to the PSCell used in MR-DC.

[0146] Specifically, in the case where SN 400 manages the change history of the PSCell included in the SCG, SN 400 may send a message including an information element (visitedCellInfoList(SN)) related to the PSCell used in the MR-DC to MN 300. Alternatively, in the case where MN 300 manages the change history of the PSCell included in the SCG, MN 300 may send a message including an information element (visitedCellInfoList(SN)) related to the PSCell used in the MR-DC to SN 400.

[0147] In addition, the MN 300 may manage the change history of the PCell used in the MR-DC. In this case, the MN may transmit to the SN 400 a message including an information element (visitedCellInfoList(MN)) related to the PCell used in the MR-DC.

[0148] Among them, the change history of the PCell used in MR-DC may include the CGI of the PCell, Cell type (cell size), Time UE Stayed In Cell, HO (Handover) cause value, and Time stamp. The information element related to the PCell used in MR-DC (visitedCellInfoList(MN)) may include these information elements. Time stamp is an information element used to associate the change history of the PCell (visitedCellInfoList(MN)) with the change history of the PSCell (visitedCellInfoList(SN)). Time stamp can be an information element indicating the time when the PCell is changed.

[0149] Similarly, the change history of the PSCell used in MR-DC may include the CGI of the PSCell, the Cell type (cell size), the Time spent in the PSCell, and the Time stamp. The information element related to the PSCell used in MR-DC (visitedCellInfoList(SN)) may include these information elements. The Time stamp is an information element used to associate the change history of the PCell (visitedCellInfoList(MN)) with the change history of the PSCell (visitedCellInfoList(SN)). The Time stamp may be an information element indicating the moment when the PSCell is changed. In addition, the Time spent in PSCell may be the time that the UE 200 stays in the PSCell, or the time from the establishment of the MR-DC to the release of the MR-DC, or the time from the establishment of the previous PSCell to the establishment of the next PSCell when the PSCell is changed.

[0150] The following describes an example of actions involved in Change Example 2. The following illustrates a case where EN-DC is performed as MR-DC. That is, an example is given where the eNB 100A included in the E-UTRAN 20 is the MN 300 and the gNB 100B included in the NG RAN 30 is the SN 400. However, the implementation is not limited to this. MR-DC can be either NE-DC or NR-DC.

[0151] First, a case where a message including an information element (visitedCellInfoList(SN)) related to the PSCell used in the MR-DC is sent from the SN 400 to the MN 300 is described. In this case, the SN 400 manages the information element (visitedCellInfoList(SN)) related to the PSCell used in the MR-DC. The SN 400 may also manage the visitedCellInfoList(SN) according to the method of the action examples 2 to 4 described in the embodiment. Here, a case where the MN 300 starts the action is described.

[0152] like Fig.14As shown, in step S50, MN 300 sends to SN 400 any one of a message requesting the release of SN 400 (i.e., gNB 100B) (sgNB release request), a message requesting the change of SN 400 (sgNB change request), and a message requesting the modification of SN 400 (sgNB modification request).

[0153] In step S51, SN 400 sends a response message to MN 300 for the message received in step S50. The response message is a response message (sgNB release request ack) for sgNB release request, a response message (sgNB change request ack) for sgNB change request, or a response message (sgNB modification request ack) for sgNB modification request. The response message includes an information element (visitedCellInfoList(SN)) related to the PSCell used in MR-DC. MN 300 can associate the PCell with the PSCell based on the change history of the PCell and the Time stamp included in the information element (visitedCellInfoList(SN)) related to the PSCell.

[0154] Second, a case where a message including an information element (visitedCellInfoList(SN)) related to the PSCell used in the MR-DC is sent from the SN 400 to the MN 300 is described. In this case, the SN 400 manages the information element (visitedCellInfoList(SN)) related to the PSCell used in the MR-DC. The SN 400 may also manage the visitedCellInfoList(SN) according to the method of the action examples 2 to 4 described in the embodiment. Here, a case where the action is started by the SN 400 is described.

[0155] like Fig.15As shown, in step S60, SN 400 sends any one of a message (sgNB release required) requesting the release of SN 400 (i.e., gNB 100B), a message (sgNB change required) requesting the change of SN 400, and a message (sgNB modification required) requesting the modification of SN 400 to MN 300. The message shown in step S60 includes an information element (visitedCellInfoList(SN)) related to the PSCell used in MR-DC.

[0156] In step S61, MN 300 sends a response message to SN 400 for the message received in step S60. The response message is a response message for sgNB release required (sgNB release required confirm), a response message for sgNB change required (sgNB change required confirm), or a response message for sgNB modification required (sgNB modification required confirm). The response message includes an information element (visitedCellInfoList(SN)) related to the PSCell used in MR-DC. MN 300 can associate the PCell with the PSCell based on the change history of the PCell and the Time stamp included in the information element (visitedCellInfoList(SN)) related to the PSCell.

[0157] exist Fig.15 In the example, the message shown in step S60 includes an information element (visitedCellInfoList (SN)) related to the PSCell used in the MR-DC. However, Fig.15 For example, after receiving the message shown in step S60, MN 300 may send a message requesting SN 400 for information elements (visitedCellInfoList(SN)) related to PSCells used in MR-DC, and receive a message containing information elements (visitedCellInfoList(SN)) related to PSCells from SN 400.

[0158] Third, the case where a message including an information element (visitedCellInfoList(SN)) related to the PSCell used in the MR-DC is sent from the MN 300 to the SN 400 is described. In this case, the MN 300 manages the information element (visitedCellInfoList(SN)) related to the PSCell used in the MR-DC. The MN 300 may also manage the visitedCellInfoList(SN) according to the method of the action example 1 described in the embodiment.

[0159] like Fig.16 As shown, in step S70, SN 400 sends to MN 300 any one of a message requesting the release of SN 400 (i.e., gNB 100B) (sgNB release required), a message requesting the change of SN 400 (sgNB change required), and a message requesting the modification of SN 400 (sgNB modification required).

[0160] In step S71, MN 300 sends a response message to the message received in step S70 to SN 400. The response message is a response message for sgNB release required (sgNB release required confirm), a response message for sgNB change required (sgNB change required confirm), or a response message for sgNB modification required (sgNB modification required confirm). The response message includes an information element (visitedCellInfoList(SN)) related to the PSCell used in MR-DC.

[0161] In Modification Example 2, the information element (visitedCellInfoList(SN)) related to the PSCell used in the MR-DC is mainly described. However, Modification Example 2 is not limited thereto. For example, in the case where the SN 400 manages the change history of the PSCell used in the MR-DC, the MN 300 may send a message including the information element (visitedCellInfoList(MN)) related to the PCell used in the MR-DC to the SN 400. The message including the information element (visitedCellInfoList(MN)) related to the PCell may be Fig.14The message shown in step S50 (sgNBrelease / change / modification request) may also be Fig.15 Step S61 or Fig.16 The message (sgNB release / change / modification confirm) shown in step S71 shown in the figure. SN 400 can associate PCell with PSCell according to the change history of PSCell and the Timestamp included in the information element (visitedCellInfoList(MN)) related to PCell.

[0162] According to Modification Example 2, the network (MN 300 or SN 400) can collect the change history of PSCell (for example, MobilityHistoryReport) and appropriately set the mobility parameter related to SN 400. Furthermore, the ping-pong phenomenon and connection failure of SCG change can be suppressed.

[0163] According to Modification Example 2, the information element (visitedCellInfoList(MN)) related to the PCell used in MR-DC or the information element (visitedCellInfoList(SN)) related to the PSCell used in MR-DC includes a time stamp for associating them. Therefore, in MR-DC, the PCell and the PSCell can be appropriately associated.

[0164] [Other embodiments]

[0165] Although the embodiments have been described above, it is apparent to those skilled in the art that the present invention is not limited to the description of the embodiments and that various modifications and improvements can be made.

[0166] In the embodiment, EN-DC is mainly illustrated as an example of MR-DC. However, the embodiment is not limited thereto. MR-DC may be NE-DC or NR-DC. In NE-DC, SRB3 is not set for UE 200, so action example 3 described in the embodiment may not be used.

[0167] In addition, the block diagram ( Figure 2) shows blocks in units of functions. These functional blocks (structural parts) are implemented by any combination of at least one of hardware and software. In addition, there is no particular limitation on the implementation method of each functional block. That is, each functional block can be implemented using a device that is physically or logically combined, or two or more physically or logically separated devices can be directly or indirectly connected (for example, using wires, wirelessly, etc.) and implemented using these multiple devices. The functional block can also be implemented by combining software with the above-mentioned one device or the above-mentioned multiple devices.

[0168] Functionally, it includes judging, deciding, determining, calculating, calculating, processing, deriving, investigating, searching, confirming, receiving, sending, outputting, accessing, solving, selecting, selecting, establishing, comparing, assuming, expecting, regarding, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, etc., but is not limited to these. For example, the functional block (structural part) that enables the sending function is called a transmitting unit or a transmitter. In short, as mentioned above, there is no particular limitation on the implementation method.

[0169] In addition, the above-mentioned UE 200, eNB 100A and gNB 100B (the device) can also function as a computer that processes the wireless communication method of the present disclosure. Fig.17 FIG. 1 is a diagram showing an example of the hardware structure of the device. Fig.17 As shown, the device may also be configured as a computer device including a processor 1001, a memory 1002 (memory), a storage 1003 (storage), a communication device 1004, an input device 1005, an output device 1006, and a bus 1007.

[0170] In the following description, the word "device" may be replaced by "circuit", "device", "unit", etc. The hardware structure of the device may include one or more of the devices shown in the figure, or may exclude some of the devices.

[0171] Each functional block of the device (refer to Figure 2 ) is implemented by any hardware element or combination of hardware elements of the computer device.

[0172] In addition, each function in the device is implemented by the following method: predetermined software (program) is read into hardware such as processor 1001 and memory 1002, so that processor 1001 performs calculations and controls the communication of communication device 1004 or controls at least one of the reading and writing of data in memory 1002 and storage 1003.

[0173] The processor 1001 controls the entire computer by, for example, executing an operating system. The processor 1001 may be constituted by a central processing unit (CPU) including an interface with peripheral devices, a control device, a calculation device, a register, and the like.

[0174] In addition, the processor 1001 reads a program (program code), a software module or data, etc. from at least one of the memory 1003 and the communication device 1004 to the memory 1002, and performs various processes accordingly. As a program, a program that causes a computer to perform at least a part of the actions described in the above-mentioned embodiments is used. In addition, with respect to the above-mentioned various processes, although it is described that the above-mentioned various processes are performed by one processor 1001, the above-mentioned various processes can also be performed simultaneously or sequentially by more than two processors 1001. The processor 1001 can also be installed by more than one chip. In addition, the program can also be sent from the network via a telecommunication line.

[0175] The memory 1002 is a computer-readable recording medium, and may be composed of 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 referred to as a register, a cache, a main memory (main storage device), etc. The memory 1002 may store a program (program code), a software module, etc. that can execute a method according to an embodiment of the present disclosure.

[0176] The memory 1003 is a computer-readable recording medium, and may be composed of at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a floppy disk, a magneto-optical disk (e.g., a compressed disk, a digital versatile disk, a Blu-ray (registered trademark) disk, a smart card, a flash memory (e.g., a card, a stick, a key drive), a Floppy (registered trademark) disk, a magnetic strip, etc. The memory 1003 may also be referred to as an auxiliary storage device. The above-mentioned recording medium may be, for example, other appropriate media such as a database, a server, etc. that includes at least one of the memory 1002 and the memory 1003.

[0177] The communication device 1004 is hardware (transceiver) used to communicate between computers via at least one of a wired network and a wireless network, and may also be called a network device, a network controller, a network card, a communication module, etc.

[0178] The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., for example, in order to realize at least one of frequency division duplex (FDD) and time division duplex (TDD).

[0179] The input device 1005 is an input device that receives input from the outside (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.). The output device 1006 is an output device that implements output to the outside (e.g., a display, a speaker, an LED light, etc.). In addition, the input device 1005 and the output device 1006 may also be integrally formed (e.g., a touch panel).

[0180] In addition, the processor 1001 and the memory 1002 and other devices are connected via a bus 1007 for communicating information. The bus 1007 may be configured using a single bus or may be configured using different buses for each device.

[0181] In addition, 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), a field programmable gate array (FPGA), etc., and a part or all of each functional block may be implemented by the hardware. For example, the processor 1001 may also be installed using at least one of these hardware.

[0182] In addition, the notification of information is not limited to the form / implementation method described in the present disclosure, and other methods may also be used. For example, the notification of information may be implemented through physical layer signaling (e.g., downlink control information (Downlink Control Information: DCI), uplink control information (Uplink Control Information: UCI)), high-level signaling (e.g., RRC signaling, medium access control (Medium Access Control: MAC) signaling, broadcast information (Master Information Block: MIB, System Information Block: SIB)), other signals or a combination thereof. In addition, RRC signaling may also be referred to as an RRC message, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, etc.

[0183] Each form / embodiment described in the present disclosure may also be applied to at least one of Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA 2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), a system using other appropriate systems, and a next-generation system extended therefrom. In addition, a combination of a plurality of systems (for example, a combination of at least one of LTE and LTE-A with 5G, etc.) may also be applied.

[0184] The processing procedures, timings, processes, etc. of each form / implementation described in this disclosure may be changed in order without contradiction. For example, for the method described in this disclosure, the elements of various steps are presented in an illustrative order, but are not limited to the specific order presented.

[0185] In the present disclosure, specific actions performed by a base station are sometimes performed by its upper node depending on the situation. In a network consisting of one or more network nodes having a base station, various actions performed to communicate with a terminal can be performed by at least one of the base station and other network nodes other than the base station (for example, consider MME or S-GW, etc., but not limited to these). In the above, the case where there is one other network node other than the base station is illustrated, but the other network node may also be a combination of multiple other network nodes (for example, MME and S-GW).

[0186] Information, signals (information, etc.) can be output from a higher layer (or lower layer) to a lower layer (or higher layer), and can also be input or output via multiple network nodes.

[0187] The input or output information can be stored in a specific location (e.g., memory) or managed using a management table. The input or output information can be rewritten, updated, or appended. The output information can also be deleted. The input information can also be sent to other devices.

[0188] The determination may be made by a value represented by one bit (0 or 1), by a Boolean value (Boolean: true or false), or by comparison of numerical values ​​(for example, comparison with a predetermined value).

[0189] Each form / implementation described in the present disclosure may be used alone or in combination, and may be switched depending on the execution. In addition, notification of scheduled information is not limited to being performed explicitly (e.g., notification of "yes X"), but may also be performed implicitly (e.g., notification of the scheduled information is not performed).

[0190] Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or by other names, shall be interpreted broadly to refer to commands, sets of commands, codes, code segments, program codes, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc.

[0191] In addition, software, commands, information, etc. may be sent and received via a transmission medium. For example, when software is sent from a web page, server, or other remote source using at least one of wired technology (coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and wireless technology (infrared, microwave, etc.), at least one of these wired technology and wireless technology is included in the definition of transmission medium.

[0192] The information, signals, etc. described in the present disclosure may also be represented by any of a variety of different technologies. For example, data, commands, instructions, information, signals, bits, symbols, chips, etc. that may be involved in the above description as a whole may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any combination thereof.

[0193] In addition, the terms described in the present disclosure and the terms required for understanding the present disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may also be a signal (signaling). In addition, a signal may also be a message. In addition, a component carrier (CC) may be referred to as a carrier frequency, a cell, a frequency carrier, etc.

[0194] As used in this disclosure, the terms "system" and "network" may be used interchangeably.

[0195] In addition, the information, parameters, etc. described in the present disclosure may be represented by absolute values, relative values ​​to predetermined values, or other corresponding information. For example, wireless resources may also be indicated by indexes.

[0196] The names used for the above parameters are not limiting in any way. Furthermore, the formulas etc. using these parameters may sometimes differ from those explicitly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by appropriate names, and therefore the various names assigned to these various channels and information elements are not limiting in any way.

[0197] In the present disclosure, the terms "base station (BS)", "wireless base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", "component carrier" and the like are used interchangeably. Sometimes, a base station is also referred to as a macro cell, a small cell, a micro cell, a pico cell, etc.

[0198] 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, each of which can also provide communication services through a base station subsystem (e.g., a small base station for indoor use (Remote Radio Head: RRH).

[0199] The terms "cell" or "sector" refer to a part or the entirety of a coverage area of ​​at least one of a base station and a base station subsystem that provide communication services within the coverage area.

[0200] In the present disclosure, terms such as “mobile station (MS)”, “user terminal (user terminal)”, “user equipment (UE)”, and “terminal” may be used interchangeably.

[0201] For mobile stations, those skilled in the art sometimes also use the following terms: 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 appropriate terms.

[0202] At least one of the base station and the mobile station may also be referred to as a transmitting device, a receiving device, a communication device, etc. In addition, at least one of the base station and the mobile station may be a device mounted on a mobile body, the mobile body itself, etc. The mobile body may be a means of transportation (e.g., a car, an airplane, etc.), a mobile body that moves in an unmanned manner (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). In addition, at least one of the base station and the mobile station also includes a device that does 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.

[0203] In addition, the base station in the present disclosure may also be replaced by a mobile station (user terminal, the same below). For example, various forms / implementations of the present disclosure may also be applied to a structure in which the communication between a base station and a mobile station is replaced by communication between multiple mobile stations (for example, may also be referred to as device-to-device (D2D), vehicle-to-everything (V2X), etc.). In this case, it is also possible to set a structure in which the mobile station has the functions of the base station. In addition, terms such as "uplink" and "downlink" may also be replaced by terms corresponding to communication between terminals (for example, "side"). For example, uplink channels, downlink channels, etc. may also be replaced by side channels.

[0204] Likewise, the mobile station in the present disclosure may be replaced by a base station. In this case, the base station may have the same functions as the mobile station.

[0205] A radio frame may be composed of one or more frames in the time domain. In the time domain, one or more frames may be referred to as a subframe. A subframe may be composed of one or more time slots in the time domain. A subframe may be a fixed time length (e.g., 1 ms) that is independent of a numerology.

[0206] A parameter set may be a communication parameter applied to at least one of the transmission and reception of a certain signal or channel. The parameter set may, for example, represent at least one of a subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, wireless frame structure, specific filtering processing performed by a transceiver in the frequency domain, specific windowing processing performed by a transceiver in the time domain, and the like.

[0207] A slot may be composed of one or more symbols (Orthogonal Frequency Division Multiplexing (OFDM) symbols, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols, etc.) in the time domain. A slot may be a time unit based on a parameter set.

[0208] A time slot may contain multiple mini-slots. Each mini-slot may be composed of one or more symbols in the time domain. In addition, a mini-slot may also be referred to as a sub-slot. A mini-slot may be composed of fewer symbols than a time slot. A PDSCH (or PUSCH) transmitted in units of time greater than a mini-slot may be referred to as a PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may be referred to as a PDSCH (or PUSCH) mapping type B.

[0209] A radio frame, a subframe, a time slot, a mini-time slot, and a symbol all represent time units for transmitting signals. A radio frame, a subframe, a time slot, a mini-time slot, and a symbol may be referred to by other corresponding names.

[0210] For example, 1 subframe can be called a transmission time interval (TTI), multiple consecutive subframes can also be called a TTI, and 1 time slot or 1 mini time slot can also be called a TTI. That is, at least one of the subframe and the TTI can be a subframe (1ms) in the existing LTE, or a period shorter than 1ms (for example, 1-13 code elements), or a period longer than 1ms. In addition, the unit representing TTI can be a time slot, a mini time slot, etc. instead of a subframe.

[0211] Here, TTI refers to, for example, the minimum time unit for scheduling in wireless communication. For example, in the LTE system, the base station schedules the allocation of wireless resources (frequency bandwidth, transmission power, etc. that can be used in each user terminal) to each user terminal in units of TTI. In addition, the definition of TTI is not limited to this.

[0212] TTI can be a transmission time unit for data packets (transport blocks), code blocks, code words, etc. after channel coding, or a processing unit for scheduling, link adaptation, etc. In addition, when TTI is assigned, the time interval (e.g., the number of symbols) to which the transport block, code block, code word, etc. is actually mapped can be shorter than the TTI.

[0213] In addition, when 1 time slot or 1 mini time slot is called TTI, more than one TTI (ie, more than one time slot or more than one mini time slot) can constitute the minimum time unit of scheduling. In addition, the number of time slots (mini time slots) constituting the minimum time unit of scheduling can be controlled.

[0214] A TTI having a time length of 1 ms is also called a normal TTI (TTI in LTE Rel.8-12), a normal TTI, a long TTI, a normal subframe, a normal subframe, a long subframe, a time slot, etc. A TTI shorter than a normal TTI may be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a mini-time slot, a sub-time slot, a time slot, etc.

[0215] In addition, for a long TTI (for example, a normal TTI, a subframe, etc.), it can be replaced with a TTI having a time length exceeding 1ms, and for a short TTI (for example, a shortened TTI, etc.), it can be replaced with a TTI length that is smaller than the long TTI (longTTI) and has a TTI length of more than 1ms.

[0216] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain. In the frequency domain, it may contain one or more consecutive subcarriers. The number of subcarriers contained in an RB may be the same regardless of the parameter set, for example, it may be 12. The number of subcarriers contained in an RB may also be determined according to the parameter set.

[0217] In addition, the time domain of an RB may include one or more symbols, and may be the length of 1 slot, 1 mini slot, 1 subframe, or 1 TTI. 1 TTI, 1 subframe, etc. may be composed of one or more resource blocks, respectively.

[0218] In addition, one or more RBs may be referred to as a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, and the like.

[0219] In addition, a resource block may be composed of one or more resource elements (RE). For example, 1 RE may be a radio resource region of 1 subcarrier and 1 symbol.

[0220] A Bandwidth Part (BWP) (also called a partial bandwidth, etc.) represents a subset of contiguous common RBs (common resource blocks) for a parameter set in a certain carrier. Here, a common RB can be identified by the index of the RB based on the common reference point of the carrier. PRBs are defined in a certain BWP and numbered within the BWP.

[0221] 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.

[0222] At least one of the set BWPs may be active, and it is not assumed that the UE transmits or receives a predetermined signal / channel outside the activated BWP. In addition, "cell", "carrier" and the like in the present disclosure may be replaced with "BWP".

[0223] The above structures of radio frames, subframes, time slots, mini-time slots, and symbols are only examples. For example, the number of subframes included in a radio frame, the number of time slots per subframe or radio frame, the number of mini-time slots included in a time slot, the number of symbols and RBs included in a time slot or mini-time slot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, and the like can be changed in various ways.

[0224] The terms "connected", "coupled" or all variations of these terms are intended to indicate any direct or indirect connection or combination between two or more elements, and may include the situation where there is one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The combination or connection between elements may be a physical combination or connection, a logical combination or connection, or a combination of these. For example, "access" may be used to replace "connection". In the context of the present disclosure, for two elements, it may be considered that they are "connected" or "coupled" to each other by using at least one of one or more wires, cables, and printed electrical connections, and as some non-limiting and non-inclusive examples, by using electromagnetic energy having wavelengths in the wireless frequency domain, microwave region, and light (including both visible and invisible) region, etc.

[0225] The reference signal may be referred to as Reference Signal (RS) for short, or may be referred to as a pilot signal depending on the applied standard.

[0226] The phrase "according to" used in the present disclosure does not mean "only according to" unless otherwise expressly stated. In other words, the phrase "according to" means both "only according to" and "at least according to".

[0227] The "unit" in the configuration of each of the above-mentioned devices may be replaced with a "section", "circuit", "device" or the like.

[0228] Any reference to an element using the terms "first", "second", etc. used in this disclosure does not necessarily limit the number and order of these elements. These terms are used in this disclosure as a simple method to distinguish between two or more elements. Therefore, a reference to a first and a second element does not mean that only two elements can be used here or that the first element must precede the second element in any form.

[0229] When the terms "include," "including," and variations thereof are used in the present disclosure, these terms are intended to be inclusive, as is the term "comprising." Furthermore, the term "or" used in the present disclosure does not mean an exclusive or.

[0230] In the present disclosure, when an article is added by translation, such as a, an, and the in English, for example, the present disclosure also includes the case where the noun following the article is in plural form.

[0231] The terms "determining" and "determining" used in the present disclosure sometimes also include situations of various actions. "Determining" and "determining" may include, for example, considering matters that have been judged, calculated, calculated, processed, derived, investigated, searched (for example, searched in a table, database or other data structure), confirmed (ascertaining) as matters that have been "judged" or "determined", etc. In addition, "determining" and "determining" may include considering matters that have been received (for example, receiving information), transmitted (for example, transmitting information), input, output, accessed (for example, accessed data in memory) as matters that have been "judged" or "determined", etc. In addition, "determining" and "determining" may include considering matters that have been resolved (resolving), selected (selecting), chosen (choosing), established (establishing), compared (comparing), etc. as matters that have been "judged" or "determined". That is, "determining" and "determining" may include matters that have been "judged" or "determined" by any action. In addition, the word “determine” can also be replaced by “assuming”, “expecting”, “considering”, etc.

[0232] In the present disclosure, the term "A and B are different" may also mean "A and B are different from each other". In addition, the term may also mean "A and B are different from C, respectively". The terms "separate" and "combined" may also be interpreted in the same way as "different".

[0233] The present disclosure has been described in detail above, but it should be clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented as a modified and altered method without departing from the spirit and scope of the present disclosure as determined by the claims. Therefore, the purpose of the description of the present disclosure is to illustrate and has no limiting meaning on the present disclosure.

[0234] Description of labels:

[0235] 10 Wireless Communication Systems

[0236] 20 E-UTRAN

[0237] 30 NG RAN

[0238] 40 Core Network

[0239] 50 E-SMLC

[0240] 100A eNB

[0241] 100B gNB

[0242] 200UE

[0243] 210 Wireless Signal Transceiver

[0244] 220 Amplifier Department

[0245] 230 Modem Unit

[0246] 240 Control signal and reference signal processing unit

[0247] 250 encoding / decoding unit

[0248] 260 Data transceiver unit

[0249] 270 Control Department

[0250] 1001 Processor

[0251] 1002 Memory

[0252] 1003 Memory

[0253] 1004 communication device

[0254] 1005 Input device

[0255] 1006 Output device

[0256] 1007 Bus

Claims

1. A communication node that manages a second cell group in a dual connection using a first cell group and a second cell group, in, The communication node has: a receiving unit that receives, from a terminal, a message including an information element related to a cell before the change, the information element being set as a variable by the terminal when a cell included in the second cell group is changed; and a sending unit that sends a message including an information element indicating a change history of cells included in the second cell group to other communication nodes that manage the first cell group, The sending unit sends a message including an information element indicating a change history of cells included in the second cell group to the other communication node as a response to a message requesting at least one of release and modification of cells included in the second cell group, or The sending unit sends a message including an information element indicating a change history of the cells included in the second cell group to the other communication node as a message requesting at least any one of release, change and correction of the cells included in the second cell group.

2. A wireless communication system comprising a terminal and a communication node, wherein the communication node manages the second cell group in a dual connection using a first cell group and a second cell group, in, The terminal has: a control unit that, in the dual connectivity, sets, when a cell included in the second cell group is changed, an information element related to the cell before the change as a variable; and a sending unit configured to send a message including the information element set as the variable to a network, The communication node has: a receiving unit configured to receive, from the terminal, a message including the information element set as the variable; and a sending unit that sends a message including an information element indicating a change history of cells included in the second cell group to other communication nodes that manage the first cell group, The sending unit of the communication node sends a message including an information element indicating a change history of the cells included in the second cell group to the other communication node as a response to a message requesting at least one of release and modification of the cells included in the second cell group, or, The sending unit of the communication node sends a message including an information element indicating a change history of the cells included in the second cell group to the other communication node as a message requesting at least any one of release, change and correction of the cells included in the second cell group.

3. A wireless communication method, in, The wireless communication method comprises the following steps: Step A, a communication node managing the second cell group in a dual connection using the first cell group and the second cell group receives a message including the following information element from a terminal, wherein the information element is an information element related to the cell before the change and is set as a variable by the terminal when the cell included in the second cell group is changed; as well as Step B, the communication node sends a message including an information element indicating a change history of cells included in the second cell group to other communication nodes managing the first cell group, The step B comprises the following steps: sending, to the other communication node, a message including an information element indicating a change history of cells included in the second cell group as a response to a message requesting at least one of release and modification of cells included in the second cell group, or A message including an information element indicating a change history of cells included in the second cell group is sent to the other communication node as a message requesting at least any one of release, change and correction of the cells included in the second cell group.

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