WO2022210106A1 - Terminal and wireless communication method - Google Patents

Abstract

A terminal according to the present invention comprises: a reception unit that receives an RRC reset message that includes information pertaining to setting at least one candidate cell and information pertaining to an execution condition for a specific procedure with respect to the candidate cell; and a control unit that controls the execution of the specific procedure on the basis of the information pertaining to setting and the information pertaining to the execution condition. The control unit starts a timer in response to the reception of the RRC reset message and, when the timer has expired, deletes the information pertaining to setting and the information pertaining to the execution condition.

Description

Terminal and wireless communication method Cross-reference to related applications

This application is based on Japanese Patent Application No. 2021-055162 filed on March 29, 2021, and claims the benefit of its priority, and the entire contents of that patent application are incorporated herein by reference.

The present disclosure relates to terminals and wireless communication methods.

In the Third Generation Partnership Project (3GPP), an international standardization organization, Long Term Evolution (LTE), which is the 3.9th generation Radio Access Technology (RAT), and LTE-Advanced, which is the 4th generation RAT As a successor, Release 15 of New Radio (NR), which is a fifth generation (5G) RAT, has been specified (for example, Non-Patent Document 1). LTE and/or LTE-Advanced is also called Evolved Universal Terrestrial Radio Access (E-UTRA).

E-UTRA and NR support dual connectivity (DC) in which terminals communicate using multiple cell groups (CG) each containing one or more cells. In DC, the terminal is a master node (Master Node: MN) associated with the master cell group (MCG)) and a secondary node (Secondary Node: SN) associated with the secondary cell group (Secondary Cell Group: SCG) ) and . The MCG includes one primary cell (PCell) and may include one or more secondary cells (SCell). The SCG includes one primary SCG cell (Primary SCG Cell: PSCell) and may include one or more SCells.

Currently, in 3GPP, for the purpose of improving mobility performance (for example, suppressing processing delay and / or communication interruption time, etc.), a terminal is a candidate cell for a specific procedure (hereinafter, "candidate cell ”) is satisfied, and the specific procedure is executed for candidate cells for which the execution condition is satisfied (hereinafter referred to as “conditional procedure )”) is being considered. For example, in DC, the conditional PSCell addition and / or change ( Conditional PSCell Addition and/or Change (CPAC) is being considered.

In the conditional procedure as described above, the terminal continues the processing (hereinafter referred to as "determination-related processing") regarding determination of whether or not the execution condition of the candidate cell is satisfied until the candidate cell that satisfies the execution condition is found. Resulting in. For example, in CPAC, measurements in candidate cells (eg, Inter-RAT measurement, Intra-RAT measurement, Inter-frequency measurement) are performed until a candidate cell that satisfies the execution conditions is found. ) and at least one of intra-frequency measurement), and determination-related processing such as determination based on the result of the measurement. As a result, the power consumption of the terminal may increase.
An object of the present disclosure is to provide a terminal and a wireless communication method capable of suppressing power consumption.

A terminal according to an aspect of the present disclosure includes: a receiving unit that receives an RRC reconfiguration message including information regarding configuration of one or more candidate cells and information regarding execution conditions for a specific procedure for the candidate cell; and a control unit that controls execution of the specific procedure based on the information on the execution condition and the information on the When the timer expires, remove the information about the settings and the information about the execution conditions.

According to one aspect of the present disclosure, power consumption of the terminal can be suppressed.

FIG. 1 is a diagram showing an example of an outline of a wireless communication system according to this embodiment. FIG. 2 is a diagram illustrating an example of PSCell addition (CPA). FIG. 3 is a diagram illustrating an example of UE variables. FIG. 4 is a diagram illustrating an example of PSCell change (CPC). FIG. 5 is a diagram showing an example of CPA using a timer according to this embodiment. FIG. 6 is a diagram showing an example of CPC using a timer according to this embodiment. FIG. 7 is a diagram showing an example of CPA failure reason information notification according to the present embodiment. FIG. 8 is a diagram showing an example of SCG failure information in the case of EN-DC (or NGEN-DC) according to this embodiment. FIG. 9 is a diagram showing an example of SCG failure information in the case of NR-DC according to this embodiment. FIG. 10 is a diagram showing an example of SCG failure information in the case of NE-DC according to this embodiment. FIG. 11 is a diagram showing an example of CPC failure reason information notification according to the present embodiment. FIG. 12 is a diagram showing an example of the hardware configuration of each device in the wireless communication system according to this embodiment. FIG. 13 is a diagram showing an example of a functional block configuration of a terminal according to this embodiment. FIG. 14 is a diagram showing an example of the functional block configuration of the base station according to this embodiment.

An embodiment of the present disclosure will be described with reference to the accompanying drawings. In addition, in each figure, the thing which attached|subjected the same code|symbol may have the same or the same structure.

FIG. 1 is a diagram showing an example of an overview of a wireless communication system according to this embodiment. As shown in FIG. 1, the wireless communication system 1 may include a terminal 10, base stations 20A to 20C, and a Core Network (CN) 30. Hereinafter, the base stations 20A to 20C are collectively referred to as the base station 20 when not distinguished.

The terminal 10 is, for example, a predetermined terminal or device such as a smartphone, a personal computer, an in-vehicle terminal, an in-vehicle device, a stationary device, a telematics control unit (TCU), or the like. Terminal 10 may also be called a User Equipment (UE), a Mobile Station (MS), a User Terminal, a Radio apparatus, a subscriber terminal, an access terminal, and so on. The terminal 10 may be mobile or stationary.

The terminal 10 is configured to be able to communicate using, for example, at least one of E-UTRA, NR, etc., as a RAT for the base station 20, but is not limited to this, and can communicate using a RAT of the sixth generation or later. may be configured to allow In addition, the terminal 10 is not limited to the access network defined by 3GPP as described above (3GPP access network). may access.

Each base station 20 forms one or more cells and communicates with the terminal 10 using the cell. A cell may be interchangeably referred to as a serving cell, a carrier, a component carrier (CC), and the like. For example, in FIG. 1, the base stations 20A to 20C form one cell CA to CC, respectively, but each base station 20 may form one or more cells.

The base station 20 includes gNodeB (gNB), en-gNB, eNodeB (eNB), en-gNB, Radio Access Network (RAN), Access Network (AN), Next Generation Radio Access Network (Next Generation-Radio Access Network (NG-RAN) node, NG-RAN, E-UTRAN, low-power node, Central Unit (CU), Distributed Unit (DU), gNB- It may also be called a DU, a Remote Radio Head (RRH), an Integrated Access and Backhaul/Backhauling (IAB) node, and so on. The base station 20 is not limited to one node, and may be composed of a plurality of nodes (for example, a combination of a lower node such as DU and an upper node such as CU).

The CN 30 is, for example, an Evolved Packet Core (EPC) that is a 4th generation CN or a 5G Core Network (5GC) that is a 5th generation CN, but is not limited to this. For example, the CN 30 can use various CNs, such as CNs of the sixth generation or later. A device on the CN 30 (hereinafter also referred to as a “core network device”) performs mobility management such as paging and location registration of the terminal 10 . A core network device may be connected to the base station 20 via a predetermined interface (eg, S1 or NG interface).

The core network device includes, for example, an Access and Mobility Management Function (AMF) that manages C-plane information (e.g., information related to access and mobility management), and a User that controls transmission of U-plane information (e.g., user data). At least one of Plane Function (UPF), Mobility Management Entity (MME), Gateway (GW), etc. may be included.

The numbers of terminals 10 and base stations 20 shown in FIG. 1 are not limited to those shown. The plurality of base stations 20 are interconnected via a predetermined interface (for example, X2 or Xn interface).

In the wireless communication system 1, the terminal 10 receives downlink (DL) signals from the base station 20 and/or transmits uplink (UL) signals. One or more cells are configured in the terminal 10, and at least one of the configured cells is activated. The maximum bandwidth of each cell is, for example, 20 MHz or 400 MHz.

The terminal 10 uses a carrier aggregation (CA) that integrates a plurality of cells of one base station 20, and/or a plurality of cell groups formed by a plurality of base stations 20 (Cell Group: CG ) to communicate. For example, in the case of dual connectivity (Dual Connectivity: DC) connecting to two base stations 20, one base station 20 is called a master node (Master Node: MN), and the other base station 20 is a secondary node (Secondary Node :SN). A CG formed by an MN is called a Master Cell Group (MCG), and a CG formed by an SN is called a Secondary Cell Group (SCG). The MCG and SCG may also be called a first cell group and a second cell group, respectively, and so on.

Each of the MCG and SCG includes at least a primary cell (PCell) and may include one or more secondary cells (SCell). PCell of SCG is also called a primary SCG cell (Primary SCG Cell: PSCell). Moreover, PCell of MCG or SCG is also called a special cell (Special Cell: SpCell). SpCells and one or more SCells within each CG are aggregated by a CA. Each CG corresponds to a Medium Access Control (MAC) entity for each base station 20 . Radio Resource Control (RRC) layer messages (hereinafter referred to as “RRC messages”) are transmitted and/or received by SpCells of each CG. Also, reconfiguration with sync is performed in the SpCell of each CG.

The RATs used by the MN and SN to communicate with the terminal 10 may be the same or different. For example, a DC where MN uses E-UTRA and SN uses NR is called E-UTRA-NR Dual Connectivity (EN-DC) or NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC). A DC in which MN uses NR and SN uses E-UTRA is called NR-E-UTRA Dual Connectivity (NE-DC). A DC in which both MN and SN utilize NR is also called NR-NR Dual Connectivity (NR-DC). EN-DC, NGEN-DC, NE-DC and NR-DC are also collectively called Multi-Radio Dual Connectivity (MR-DC).

In the wireless communication system 1 as described above, the terminal 10 is considered to have a conditional procedure as described above. For example, in DC, the conditional PSCell addition and / or change ( Conditional PSCell Addition and/or Change (CPAC) is being considered.

(CPA)
FIG. 2 is a diagram showing an example of PSCell Addition (Conditional PSCell Addition: CPA). For example, in FIG. 2, when the base station 20A is the MN, the terminal 10 uses the base stations 20B and 20C as the SN candidate base stations 20 (hereinafter referred to as "SN candidates"), and adds an SN. is shown. Specifically, a procedure for performing CPA is shown with the cell CA of the base station 20A as the PCell and the cells CB and CC of the base stations 20B and 20C as PSCell candidate cells (hereinafter referred to as "PSCell candidates").

In step S101 of FIG. 2, the base station 20A as the MN decides to perform CPA, and transmits an SN Addition Request to the SN candidate base stations 20A and 20B. Here, the SN addition request is a message requesting addition of SN or PSCell, and is also called "S-NODE ADDITION REQUEST" or "SgNB Addition Request". An SN addition request may be sent for each PSCell candidate. For example, in FIG. 2, PSCell candidates are cells CB and CC of base stations 20B and 20C, respectively, so SN addition requests for cells CB and CC, respectively, are transmitted.

The SN addition request may include, for example, the identifier of the PSCell candidate (eg, cell ID), the identifier of the terminal 10, and information used in the SN candidate (eg, RRC IE "CG-ConfigInfo"). The information includes, for example, information on the capability of the terminal 10, information on measurement results of each cell in the terminal 10, and the like.

In step S102, the base stations 20B and 20C transmit SN Addition Request Acknowledge to the base station 20A in response to the SN addition request. Here, the SN addition request acknowledge is a message that accepts the addition of the SN or PSCell, and is also called "S-NODE ADDITION REQUEST ACKNOWLEDGE" or "SgNB Addition Request Acknowledge". An add SN request acknowledgment may be sent for each PSCell candidate, eg in FIG. 2 an add SN request acknowledgment for cells CB and CC respectively is sent.

The SN addition request acknowledgment may include, for example, (1) information on setting of PSCell candidates (hereinafter referred to as “PSCell candidate setting information”) and (2) information on execution conditions (hereinafter “execution condition information”). good. The PSCell candidate configuration information and execution condition information may be generated by the SN candidate and included in the configuration information regarding the SCG (eg, RRC IE "CG-Config"). The execution condition information may be generated by the SN candidate and included in the SN addition request acknowledge, or may be generated by the MN without being generated by the SN candidate. When the execution condition information is generated by the MN, the SN addition request acknowledgment may contain the PSCell candidate configuration information without containing the execution condition information. The PSCell candidate configuration information may include an RRC reconfiguration message (RRC Reconfiguration Message). The RRC reconfiguration message is a message used to reconfigure the RRC connection of the terminal 10, and is also called "RRCReconfiguration" or "RRCConnectionReconfiguration". The RRC reconfiguration message is used in terminal 10 to configure PSCell candidates.

In step S103, the base station 20A transmits to the terminal 10 an RRC reconfiguration message including PSCell candidate configuration information and execution condition information for one or more PSCell candidates. The PSCell candidate configuration information (eg, RRC IE "CondRRCReconfig") may be based on the PSCell candidate configuration information included in the SN addition request acknowledgment from one or more SN candidates (eg, from one or more SN candidates to the MN may include the RRC reconfiguration message sent). Also, the execution condition information (for example, RRC IE "CondExecutionCond") may be based on the execution condition information included in the SN addition request acknowledgment from one or more SN candidates, or may be generated by the MN. Each PSCell candidate configuration information and execution condition information may be included as an entry (eg, RRC IE 'CondReconfigToAddMod') in a predetermined list (eg, RRC IE 'CondReconfigToAddModList'). The terminal 10 may store the list in UE variables (eg, "VarConditionalReconfig").

In addition, the RRC reconfiguration message in step S103 or each PSCell candidate configuration information in the RRC reconfiguration message is information about the measurement configuration in the terminal 10 (hereinafter referred to as "measurement configuration information", for example, RRC IE "MeasConfig") may include The measurement configuration information may be generated at the MN. The MN may generate the measurement configuration information, eg, based on the PSCell candidate configuration information. The measurement setting information is, for example,
(1) a list (for example, RRC IE “MeasObjectToAddModList”) containing information about one or more measurement objects (hereinafter referred to as “measurement object information”);
(2) a list (e.g., RRC IE “ReportConfigToAddModList”) containing information about reports (hereinafter referred to as “report information”); and
(3) a list (for example, RRC IE “MeasIdToAddModList”) of information (hereinafter referred to as “association information”) relating to association between measurement target information and report information;
At least one of the like may be included. The terminal 10 stores the list of measurement target information, the list of report information, and the list of association information included in the measurement configuration information as UE variables (for example, "measObjectList", "reportConfigList" and "measIdList" of "VarMeasConfig"). ) may be stored.

Each piece of measurement target information (eg, RRC IE "MeasObject") may indicate, for example, the identifier, frequency, etc. of the measurement target cell (eg, a plurality of cells including the PSCell candidate). The association information between the measurement target information (e.g., RRC IE 'measObject') and the report information (e.g., RRC IE 'reportConfig') is, for example, the identifier of the measurement target information (e.g., RRC IE 'measObjectId'), the report information An identifier (eg, RRC IE 'reportConfigId') and an identifier of the association information (hereinafter referred to as 'association identifier', eg, RRC IE 'measId') may be included.

Each report information (e.g., RRC IE "reportConfig") contains information about an event that triggers a conditional procedure (e.g., CPA) (hereinafter referred to as "event trigger information", e.g., RRC IE "CondTriggerConfig"). may contain. The event is, for example,
(A3) that the measurement result of the PSCell candidate is better than the measurement result of the PCell and/or PSCell by a predetermined offset amount, or (A4) that the measurement result of the PSCell candidate is better than a threshold value, or (A5) the PCell and / or the PSCell measurement result is worse than the threshold T1 and the PSCell candidate is better than the threshold T2, or (B1) the measurement result of the neighboring cell of a different RAT (from the serving cell) is better than the threshold etc.

Also, each piece of execution condition information (eg, RRC IE "CondExecutionCond") may include, for example, a correlation identifier (eg, RRC IE "measId") between the measurement target information and the report information. "The execution condition is satisfied" may be the occurrence of an event indicated by the event trigger information in the report information specified by the association identifier (for example, the above event (A3) or (A5), etc.). .

FIG. 3 is a diagram showing an example of UE variables. For example, in FIG. 3, the terminal 10 receives a list (for example, An example of storing the RRC IE "CondReconfigToAddModList") in the UE variable "VarConditionalReconfig" is shown.

As shown in FIG. 3, the UE variable "VarConditionalReconfig" contains the ID of the combination of the PSCell candidate setting information and the execution condition information for each of the cells CB and CC (for example, RRC IE "condReconfigId") and the PSCell candidate setting information (for example, RRC IE 'CondRRCReconfig') and the execution condition information (for example, RRC IE 'CondExecutionCond') are stored.

"measObjectList" in the UE variable "VarMeasConfig" stores the above measurement target information list (eg, RRC IE "MeasObjectToAddModList"). Also, the list of report information (for example, RRC IE "ReportConfigToAddModList") is stored in "reportConfigList" in the UE variable "VarMeasConfig". In addition, the "measIdList" in the UE variable "VarMeasConfig" stores a list of association information between the measurement target information and the report information (for example, RRC IE "MeasIdToAddModList").

As shown in FIG. 3, the execution condition information of the cell CB corresponding to the condReconfigId "1" in the UE variable "VarConditionalReconfig" is the association identifier (measId) "1" in the "measIdList" in the UE variable "VarMeasConfig". Specifies association information. The association information specifies measurement target information (measObject) #1 and report information (reportConfig) #1. In this case, the terminal 10 performs measurement for the CPA of the cell CB based on the measurement target information #1. Also, when the event indicated by the event trigger information in the report information #1 occurs, the terminal 10 determines that the CPA execution conditions for the cell CB are satisfied.

On the other hand, the execution condition information of the cell CC corresponding to condReconfigId "2" in the UE variable "VarConditionalReconfig" specifies the association information of the association identifier (measId) "3" in "measIdList" in the UE variable "VarMeasConfig". . The association information specifies measurement object information (measObject) #3 and report information (reportConfig) #3. In this case, terminal 10 performs measurement for CPA of cell CC based on measurement target information #3. Also, when the event indicated by the event trigger information in the report information #3 occurs, the terminal 10 determines that the CPA execution conditions for the cell CC are satisfied.

In step S104 of FIG. 2, the terminal 10 transmits an RRC reconfiguration complete message (RRC Reconfiguration Complete Message) in response to the RRC reconfiguration message from the base station 20A in step S103. The RRC reconfiguration message is also called "RRCReconfigurationComplete" or "RRCConnectionReconfigurationComplete".

In step S105, the terminal 10 performs measurement in the measurement target cell. Specifically, the terminal 10 may perform measurements in the cell based on the measurement target information. For example, as described with reference to FIG. 3, the terminal 10 may measure the cells specified by the measurement target information #1 and #3 for the CPA of the PSCell candidate cells CB and CC, respectively.

In step S106, the terminal 10 determines whether the execution condition of each PSCell candidate is satisfied. Specifically, the terminal 10 may determine whether or not the execution condition of each PSCell candidate is satisfied based on the measurement result in step S105 and the report information. For example, as described with reference to FIG. 3, the terminal 10 determines whether an event indicated by the event trigger information in the report information #1 and #3 occurs for the CPA of the PSCell candidate cells CB and CC, respectively. You can judge.

If the execution condition of any PSCell candidate is not satisfied (step S106; NO), the operation returns to step S105, and the terminal 10 continues measurement.

If the execution condition for at least one PSCell candidate is satisfied (step S106; YES), in step S107, the terminal 10 starts a random access procedure for the PSCell candidate that satisfies the execution condition. For example, in FIG. 2, the execution condition of the PSCell candidate cell CB is satisfied, so the terminal 10 sets the PSCell candidate configuration information of the cell CB (for example, condRRCReconfig of condReconfigId “1” in the UE variable “VarConditionalReconfig” in FIG. 3) to initiate a random access procedure for cell CB. Note that, when execution conditions for a plurality of PSCell candidates are satisfied, the terminal 10 may select one of the plurality of PSCell candidates and initiate a random access procedure for the selected PSCell candidate.

In step S108, when the RRC connection with the base station 20B (cell CB) is established, the terminal 10 transmits an RRC message notifying that the cell CB has been set as the PSCell to the base station 20A. The RRC message may include an RRC reconfiguration complete message corresponding to the RRC reconfiguration message of the cell CB included in the PSCell candidate configuration information in step S102.

The RRC message including the RRC reconfiguration complete message is, for example, a measurement report (“MeasurementReport”) triggered by satisfying the execution condition in step S106, or the RRC received from the base station 20B in the random access procedure in step S107. An RRC setup completion message (“RRCSetupComplete” or “RRCConnectionSetupComplete”) in response to a setup message (“RRCSetup” or “RRCConnectionSetup”), but not limited to these, and may be any RRC message.

In step S109, the base station 20A transmits SN Reconfiguration Complete to the base station 20B forming the cell CB. The SN reconfiguration complete is a message that notifies that the PSCell candidate configuration information generated by the SN candidate has been applied in the terminal 10, and is also called, for example, "S-NODE RECONFIGURATION COMPLETE" or "SgNB Reconfiguration Complete". The SN reset completion includes the RRC reset completion message of the cell CB received from the terminal 10 in step S108.

In step S110, the base station 20A performs the SN release procedure with the SN candidate (here, the base station 20C) forming the SPCell candidate that was not set as the PSCell. For example, the base station 20A transmits an SN release request (SN Release Request) to the base station 20C. The SN release request is a message requesting release of the PSCell candidate configuration information for the SPCell candidate (here, cell CC) generated by the SN candidate, and is also called "S-NODE RELEASE REQUEST" or "SgNB Release Request". be called.

As described above, when the execution condition of the cell CB is satisfied and the cell CB is added as a PSCell, the terminal 10 removes the specific entry of the UE variable in step S111. Specifically, the terminal 10 may remove PSCell candidate configuration information and execution condition information of all PSCell candidates (for example, all entries of “VarConditionalReconfig” in FIG. 3). In addition, the terminal 10 uses the report information (eg, reportConfig #1 and #3 in FIG. 3) specified based on the execution condition information in the UE variables (eg, "reportConfigList" of "VarMeasConfig" in FIG. 3) may be removed. In addition, the terminal 10 specifies measurement target information (for example, measObject #1 and #3 ) may be removed. In addition, the terminal 10 stores the association information (for example, MeasId"1", measObjectId"1" in FIG. 3) specified by the execution condition information in the UE variable (for example, "measIdList" in "VarMeasConfig" in FIG. 3). and the set of reportConfigId"1" and the set of MeasId"3", mesasObjectId"3" and reportConfigId"1").

(CPC)
FIG. 4 is a diagram showing an example of PSCell change (Conditional PSCell Change: CPC). For example, in FIG. 4, when the terminal 10 performs DC with the base station 20A as the MN and the base station 20B as the source SN, the base station 20C is used as a target SN candidate (hereinafter referred to as "target SN candidate"), and the MN A procedure for manually changing the SN is shown. That is, when the cell CA of the base station 20A is the PCell and the cell CB of the base station 20B is the PSCell, the procedure for performing CPC using the cell CC of the base station 20C as a PSCell candidate is shown.

In addition, in FIG. 4, the description will focus on the differences from FIG. 2, and the same description will not be repeated. Also, CPA in the description of FIG. 2 is read as CPC in FIG. Also, the description of the PSCell candidates “cells CB and CC” in the description of FIG. 2 is applied by reading “cell CC” in FIG. 4 .

In step S201 of FIG. 4, the base station 20A as the MN decides to perform CPC, and transmits an SN addition request to the target SN candidate base station 20C. For example, in FIG. 4, the PSCell candidate is the cell CC of the base station 20C, so an SN addition request for the cell CC is transmitted.

In step S202, the base station 20C transmits an SN addition request acknowledge to the base station 20A in response to the SN addition request. For example, in FIG. 4, an SN addition request acknowledgment including PSCell candidate configuration information and/or execution condition information of the cell CC is sent.

Steps S203 to S206 in FIG. 4 are the same as steps S103 to S106 in FIG. If the execution condition of at least one PSCell candidate is satisfied (YES in step S206), in step S207, the terminal 10 transmits an RRC message that triggers a PSCell change to the PSCell candidate that satisfies the execution condition. The RRC message may be, for example, a measurement report triggered by fulfilling an execution condition in step S206.

In step S208, the base station 20A, in response to the RRC message from the terminal 10, performs the SN release procedure with the base station 20B as the source SN. The SN release procedure stops data transmission and/or reception with the terminal 10 whose SN is the base station 20B. Steps S210, S211 and S212 are the same as steps S108, S109 and S111 in FIG.

Although not shown, CPC may be performed at the initiative of the SN. In the SN-driven case, a step of transmitting an SN change request from the base station 20B as the source SN to the base station 20A as the MN may be added before step S201 in FIG. The SN change request is a message requesting a change of SN, and may be called "S-NODE CHANGE REQUIRED" or "SgNB Change Required".

As described above, in a conditional procedure (for example, CPAC), the terminal 10 includes one or more PSCell candidate configuration information (information on candidate cell configuration), execution condition information (execution condition for a specific procedure for the candidate cell ) and receive an RRC reconfiguration message containing The terminal 10 controls execution of a specific procedure based on the PSCell candidate setting procedure and the execution condition information. In such a conditional procedure, one or more candidate cells are set in advance in the terminal 10. Therefore, when it is determined that the execution condition of a certain candidate cell is satisfied, the specific procedure for that certain candidate cell is quickly executed. can start at As a result, improvement in mobility performance (for example, suppression of processing delay and/or communication interruption time, etc.) can be expected.

However, in the above conditional procedure, the terminal 10 continues the determination-related processing as to whether or not the execution condition of the candidate cell is satisfied until the candidate cell that satisfies the execution condition is found. For example, in CPAC, measurements in candidate cells (e.g., Inter-RAT measurement, Intra-RAT measurement, Inter-frequency measurement) are performed until a candidate cell that satisfies the execution conditions is found. ) and at least one of intra-frequency measurement), and determination-related processing such as determination based on the result of the measurement. As a result, the power consumption of the terminal may increase.

Also, even if the conditional procedure fails in the terminal 10, the network (eg, the base station 20 and the CN 30, etc.) cannot know the reason for the failure of the conditional procedure in the terminal 10. Therefore, the network cannot properly take measures to prevent failure (for example, adjustment of PSCell candidate setting information and/or execution condition information), and as a result, the utilization efficiency of the resources of the entire system decreases. there is a risk of

Therefore, in the present embodiment, (1) a timer is used to limit the processing related to the determination of whether or not the execution condition is satisfied, and/or (2) information about the reason for the failure of the conditional procedure (hereinafter referred to as , “failure reason information”) is notified from the terminal 10 to the network. By using the timer, it is possible to reduce the power consumption of the terminal 10 when no candidate cell that satisfies the execution condition is found. Also, by notifying the failure reason information, it is possible to take countermeasures on the network side, so that it is possible to improve the utilization efficiency of the resources of the entire system.

(1) Restriction of Processing Related to Execution Condition Determination Using Timer The terminal 10 receives an RRC reconfiguration message including PSCell candidate configuration information and execution condition information for one or more PSCell candidates. The terminal 10 starts a timer in response to receiving the RRC reconfiguration message, and removes the PSCell candidate configuration information and execution condition information when the timer expires.

FIG. 5 is a diagram showing an example of CPA using a timer according to this embodiment. In FIG. 5, the description will focus on the differences from FIG. Steps S301 to S303 in FIG. 5 are the same as steps S101 to S103 in FIG.

In step S304, the terminal 10 starts a timer in response to receiving an RRC reconfiguration message including one or more PSCell candidate configuration information and a list of execution condition information (for example, RRC IE "CondReconfigToAddModList") from the base station 20A. do. The RRC reconfiguration message may include information about the timer (hereinafter referred to as "timer information"). The timer information may indicate, for example, the value or period of the timer. Note that the timer value or period may be set commonly for all PSCell candidates of the terminal 10 or may be set individually for each PSCell candidate of the terminal 10 . Step S305 is the same as step S104 in FIG.

In step S306, the terminal 10 determines whether the timer started in step S304 has expired. If the timer has not expired (step S306; NO), the terminal 10 measures the measurement target cell in step S307, and determines whether or not the execution condition of each PSCell candidate is satisfied in step S308. . Details of the measurement in step S307 and the determination in step S308 are the same as those in steps S105 and S106 in FIG.

If the execution condition of at least one PSCell candidate is satisfied (step S308; YES), in step S309, the terminal 10 stops the timer started in step S304. In step S310, the terminal 10 operates as described in steps S107 to S110 of FIG. 2, and proceeds to step S311.

On the other hand, if none of the PSCell candidate execution conditions are satisfied (step S308; NO), the operation returns to step S306, and the terminal 10 determines whether the timer started in step S304 has expired. If the timer has expired (step S306; YES), the operation proceeds to step S311. Step S311 is the same as step S111 in FIG.

As described above, in FIG. 5, even if the execution condition of any PSCell candidate is not satisfied in step S308, when it is determined that the timer expires in step S306, the terminal 10 receives the PSCell candidate setting information and the execution condition in step S311. Remove conditional information. That is, the terminal 10 suspends the determination-related processing for CPA when the timer expires, so power consumption of the terminal 10 can be suppressed.

FIG. 6 is a diagram showing an example of CPC using a timer according to this embodiment. In FIG. 6, the description will focus on the differences from FIGS. Steps S401 to S403 in FIG. 6 are the same as steps S201 to S203 in FIG.

In step S404, the terminal 10 starts a timer in response to receiving an RRC reconfiguration message including one or more PSCell candidate configuration information and a list of execution condition information (for example, RRC IE "CondReconfigToAddModList") from the base station 20A. do. The RRC reconfiguration message may include the timer information. Step S405 is the same as step S204 in FIG.

In step S406, the terminal 10 determines whether the timer started in step S404 has expired. If the timer has not expired (step S406; NO), the terminal 10 measures the measurement target cell in step S407, and determines whether the execution condition of each PSCell candidate is satisfied in step S408. . Details of the measurement in step S407 and the determination in step S408 are the same as those in steps S205 and S206 in FIG.

If the execution condition of at least one PSCell candidate is satisfied (step S408; YES), the terminal 10 stops the timer started in step S404 in step S309. In step S410, the terminal 10 operates as described in steps S207 to S211 of FIG. 4, and proceeds to step S411.

On the other hand, if none of the PSCell candidate execution conditions are satisfied (step S408; NO), the operation returns to step S406, and the terminal 10 determines whether the timer started in step S404 has expired. If the timer has expired (step S406; YES), the operation proceeds to step S411. Step S411 is the same as step S212 in FIG.

Thus, in FIG. 6, even if the execution condition of any PSCell candidate is not satisfied in step S408, if it is determined in step S406 that the timer expires, in step S311, the terminal 10 receives the PSCell candidate setting information and execution Remove conditional information. That is, the terminal 10 suspends the determination-related processing for CPC when the timer expires, so power consumption of the terminal 10 can be suppressed.

As described above, terminal 10 starts a timer in response to receiving an RRC reconfiguration message including one or more PSCell candidate configuration information and execution condition information, and when the timer expires, PSCell candidate configuration information and execution condition By removing the information, it is possible to suppress the power consumption of the terminal 10 when no candidate cell that satisfies the execution condition is found.

For example, in FIGS. 5 and 6, instead of starting the timer in the terminal 10, it is also assumed that the network (eg, MN) starts the timer in response to receiving the RRC reconfiguration complete message. In this case, when the timer started on the network side expires, signaling for removing the PSCell candidate configuration information and the execution condition information (for example, an RRC reconfiguration message from the MN to the terminal 10, the terminal 10 for the RRC reconfiguration message to MN) is required. Therefore, when the terminal 10 starts the timer as shown in FIGS. 5 and 6, the overhead associated with CPAC control can be reduced compared to the case where the network side starts the timer.

(2) Notification of failure reason information The terminal 10 receives an RRC reconfiguration message including PSCell candidate configuration information and execution condition information for one or more PSCell candidates. The terminal 10 controls execution of a specific procedure based on the PSCell candidate setting information and execution condition information. When the terminal 10 fails to execute the specific procedure, it transmits a message (for example, an RRC message) including failure reason information regarding the reason for the failure.

FIG. 7 is a diagram showing an example of CPA failure reason information notification according to the present embodiment. In FIG. 7, the description will focus on the differences from FIGS. Steps S501 to S504 in FIG. 7 are the same as steps S101 to S104 in FIG. 2 and steps S301 to S304 in FIG.

In step S505, the terminal 10 detects CPA failure. For example, the terminal 10 may detect CPA failure in at least one of the following cases (a) to (c).
(a) at least one PSCell candidate configured based on the list of PSCell candidate configuration information received in step S503 cannot be detected within a given period;
(b) the at least one PSCell candidate was detected within a predetermined period, but the execution condition of the detected PSCell candidate was not satisfied within the predetermined period, or (c) execution of the detected PSCell candidate conditions were met within a predetermined period of time, but the random access procedure failed for a PSCell candidate that satisfies the execution conditions;

The predetermined period may be a predetermined period or a period set by the network. Further, the predetermined period may be a period from when the timer in step S306 of FIG. 5 is activated in response to the reception of the RRC reconfiguration message in step S305 to when it expires. Note that in FIG. 7, when the timer expires, step S311 in FIG. 5 may be performed.

In step S506, the terminal 10 transmits SCG failure information (SCG Failure Information) including failure reason information regarding the reason for the failure detected in step S505 to the base station 20A. Here, the SCG failure information is a message notifying the failure of the SCG procedure, and may be, for example, an RRC message. SCG failure information, "SCGFailureInformation" to notify the failure of the procedure for SCG of NR in NR-DC, "SCGFailureInformationEUTRA" to notify the failure of the procedure for SCG of E-UTRA in NE-DC, or NR in EN-DC It may be paraphrased as "SCGFailureInformationNR" or the like that notifies the failure of the procedure related to the SCG.

The failure reason information may indicate, for example, at least one of the following (a) to (c). If the failure reason information is (b) above, the SCG failure information may include information about the at least one PSCell candidate detected within a predetermined period of time. Moreover, when the failure reason information is (c) above, the SCG failure information may include information on PSCell candidates that satisfy the execution conditions. The information about the PSCell candidate detected within the predetermined period or satisfying the execution condition may be, for example, identification information (eg, physical cell ID) of the PSCell candidate.

In addition, the SCG failure information may include information on other cells detected in the terminal 10 other than the above PSCell candidates (hereinafter referred to as "other cell information"). The other cell information may include identification information (for example, physical cell ID) of the other cell detected by the terminal 10 and/or information related to the measurement result of the other cell.

An example of the above SCG failure information will be described with reference to FIGS. FIG. 8 is a diagram showing an example of SCG failure information in the case of EN-DC (or NGEN-DC) according to this embodiment. For example, as shown in FIG. 8, 'SCGFailureInformationNR' used in EN-DC may include failure reason information (eg, 'cpa-FailureCause' in RRC IE 'CPA-FailureInformation'). The failure reason information is, for example, information indicating any of the above (a) to (c) (for example, (a) noPSCellDetected, (b) noEventFulfilled, or (c) rach-Failure), (b) and It may also include the physical cell ID (eg, “PhysCellIdNR”) of the PSCell candidate in case (c). Also, "SCGFailureInformationNR" may include other cell information (for example, otherDetectedCellList).

FIG. 9 is a diagram showing an example of SCG failure information in the case of NR-DC according to this embodiment. For example, as shown in FIG. 9, ``SCGFailureInformation'' used in NR-DC may contain failure reason information (for example, ``cpa-FailureCause'' in RRC IE ``CPA-FailureInformation'') as in FIG. good. Also, "SCGFailureInformation" may include other cell information (for example, otherDetectedCellList).

FIG. 10 is a diagram showing an example of SCG failure information in the case of NE-DC according to this embodiment. For example, as shown in FIG. 10, "SCGFailureInformationEUTRA" used in NE-DC may contain failure reason information (for example, "cpa-FailureCause" in RRC IE "CPA-FailureInformation") as in FIG. good. Also, "SCGFailureInformation" may include other cell information (for example, otherDetectedCellList).

In step S507, the base station 20A performs an SN release procedure with the SN candidates forming each SPCell candidate (here, each of the base stations 20B and 20C) in response to receiving the SCG failure information in step S506. For example, base station 20A transmits an SN release request to each of base stations 20B and 20C.

The SN release request may include the above failure reason information. The SN candidate base stations 20B and 20C may control generation of PSCell candidate configuration information and/or execution condition information in response to the next SN addition request from the MN based on the failure reason information in the SN release request. good. In this way, countermeasures on the network side based on the failure reason information may be taken by SN candidates.

Alternatively, the base station 20A may generate information (eg, RRC IE "CG-ConfigInfo") used in SN candidates based on the failure reason information and/or other cell information included in the SCG failure information. Also, the base station 20A may determine PSCell candidates and/or SN candidates based on the failure reason information and/or other cell information. In this way, network-side countermeasures based on the failure reason information may be taken by the MN.

Further, for example, when the failure reason information indicates the above (a), the network (for example, MN) uses the other cell information reported from the terminal 10, the actually detected cell indicated by the other cell information may be set in the terminal 10 as a PSCell candidate.

Also, for example, when the failure reason information indicates the above (b), the network (for example, MN and/or SN candidates) may review the execution conditions and set values such as thresholds. Also, for example, when the failure reason information indicates the above (c), the network (eg, MN and/or SN candidate) can also review parameters related to random access in the PSCell candidate configuration information.

In this way, in FIG. 7, the notification of the failure reason information in step S506 enables the network side to take countermeasures against CPA, so it is possible to improve the utilization efficiency of the resources of the entire system.

FIG. 11 is a diagram showing an example of CPC failure reason information notification according to the present embodiment. FIG. 11 will be described with a focus on differences from FIGS. Steps S601 to S604 in FIG. 11 are the same as steps S201 to S204 in FIG.

In step S605, the terminal 10 detects CPC failure. For example, the terminal 10 may detect CPC failure in at least one of the above cases (a) to (c), as described in step S505 of FIG.

In step S606, the terminal 10 transmits SCG failure information including failure reason information regarding the reason for the failure detected in step S605 to the base station 20A. The details of step S606 are the same as those of step S506 in FIG. The SCG failure information can be applied by replacing CPA shown in FIGS. 8 to 10 with CPC.

In step S607, the base station 20A performs the SN release procedure with the SN candidates forming each SPCell candidate (here, the base station 20C) in response to receiving the SCG failure information in step S606. The details of step S607 are the same as those of step S507 in FIG.

Thus, in FIG. 11, the notification of the failure reason information in step S606 enables countermeasures against CPC on the network side, so that the resource usage efficiency of the entire system can be improved.

In the above, CPA (e.g., FIGS. 2, 5 and 7) and CPC (e.g., FIGS. 4, 6 and 11) are illustrated as examples of conditional procedures, but in this embodiment, only CPA and CPC It is also applicable to Conditional Hand Over (CHO). In the case of CHO, the candidate cell should be read as the candidate cell of the target cell (or target base station).

(Configuration of wireless communication system)
Next, the configuration of each device of the radio communication system 1 as described above will be described. Note that the following configuration is for showing the configuration required in the description of the present embodiment, and does not exclude that each device has functional blocks other than those illustrated.

<Hardware configuration>
FIG. 12 is a diagram showing an example of the hardware configuration of each device in the wireless communication system according to this embodiment. Each device in the wireless communication system 1 (for example, the terminal 10, the base station 20, the CN 30, etc.) includes a processor 11, a storage device 12, a communication device 13 that performs wired or wireless communication, an input device that receives various input operations, and various It includes an input/output device 14 for outputting information.

The processor 11 is, for example, a CPU (Central Processing Unit) and controls each device within the wireless communication system 1 . The processor 11 may read and execute the program from the storage device 12 to execute various processes described in this embodiment. Each device within the wireless communication system 1 may be configured with one or more processors 11 . Each device may also be called a computer.

The storage device 12 is composed of storage such as memory, HDD (Hard Disk Drive) and/or SSD (Solid State Drive). The storage device 12 may store various types of information necessary for execution of processing by the processor 11 (for example, programs executed by the processor 11, etc.).

The communication device 13 is a device that communicates via a wired and/or wireless network, and may include, for example, network cards, communication modules, chips, antennas, and the like. Further, the communication device 13 may include an amplifier, an RF (Radio Frequency) device that performs processing related to radio signals, and a BB (BaseBand) device that performs baseband signal processing.

For example, the RF device generates a radio signal to be transmitted from the antenna A by performing D/A conversion, modulation, frequency conversion, power amplification, etc. on the digital baseband signal received from the BB device. Further, the RF device generates a digital baseband signal by performing frequency conversion, demodulation, A/D conversion, etc. on the radio signal received from the antenna, and transmits the digital baseband signal to the BB device. The BB device performs a process of converting a digital baseband signal into a packet and a process of converting the packet into a digital baseband signal.

The input/output device 14 includes input devices such as keyboards, touch panels, mice and/or microphones, and output devices such as displays and/or speakers.

The hardware configuration described above is just an example. Each device in the wireless communication system 1 may omit part of the hardware shown in FIG. 12, or may include hardware not shown in FIG. Also, the hardware shown in FIG. 12 may be configured by one or a plurality of chips.

<Functional block configuration>
≪Device≫
FIG. 13 is a diagram showing an example of a functional block configuration of a terminal according to this embodiment. As shown in FIG. 13 , terminal 10 includes receiver 101 , transmitter 102 , and controller 103 .

All or part of the functions realized by the receiving unit 101 and the transmitting unit 102 can be realized using the communication device 13. All or part of the functions realized by the receiving unit 101 and the transmitting unit 102 and the control unit 103 can be realized by the processor 11 executing a program stored in the storage device 12 . Also, the program can be stored in a storage medium. The storage medium storing the program may be a non-transitory computer readable medium. The non-temporary storage medium is not particularly limited, but may be a storage medium such as a USB memory or CD-ROM, for example.

The receiving unit 101 receives the downstream signal. Also, the receiving section 101 may receive information and/or data transmitted via a downlink signal. Here, "receiving" may include, for example, performing processing related to reception such as at least one of receiving, demapping, demodulating, decoding, monitoring, and measuring radio signals. Downlink signals, for example, downlink control channel (e.g., physical downlink control channel (PDCCH), downlink shared channel (e.g., physical downlink shared channel (PDSCH), downlink reference signal, synchronization signal , a broadcast channel, and/or the like.

Receiving section 101 monitors PDCCH candidates in the search space to detect downlink control information (DCI). Receiving section 101 may receive PDSCH based on DCI. The receiving unit 101 may receive downlink user data and/or higher layer control information (eg, Medium Access Control Control Element (MAC CE), Radio Resource Control (RRC) message, etc.) via PDSCH.

Specifically, the receiving unit 101 provides information on setting one or more candidate cells (for example, the above PSCell candidate setting information) and information on execution conditions of a specific procedure for the candidate cell (for example, the above execution condition information). and (eg, the RRC reconfiguration messages of FIGS. 5, 6, 7 and 11). For example, the receiving unit 101 may receive the RRC reconfiguration message from the first base station (eg, MN) associated with the first cell group. The specific procedure may be a procedure of adding the candidate cell as a primary cell (eg, PSCell) of the second cell group, or a procedure of changing the primary cell to the candidate cell.

The transmission unit 102 transmits an upstream signal. Also, the transmitting section 102 may transmit information and/or data transmitted via an uplink signal. Here, "transmitting" may include performing processing related to transmission, such as at least one of encoding, modulation, mapping, and transmission of radio signals. The uplink signal is, for example, an uplink shared channel (e.g., Physical Uplink Shared channel: PUSCH), a random access preamble (e.g., Physical Random Access Channel: PRACH), at least an uplink reference signal, etc. may contain one.

The transmitting section 102 may transmit PUSCH based on the DCI received by the receiving section 101. The transmitting unit 102 may transmit uplink user data and/or higher layer control information (eg, MAC CE, RRC messages, etc.) via PUSCH. The RRC message may include, for example, the above measurement report, RRC reconfiguration complete message, SCG failure information, and the like.

Specifically, when the execution of the specific procedure fails, the transmission unit 102 may transmit a message including information on the reason for the failure (for example, the failure reason information) (for example, FIG. 7, 11 SCG failure information). For example, the transmitting unit 102 may transmit the message to the first base station (eg, MN) associated with the first cell group.

The information about the reason for the failure is (a) that the candidate cell could not be detected within the predetermined period, (b) that the candidate cell was detected within the predetermined period but the execution condition was not satisfied, and ( c) at least one of said execution conditions for said candidate cells being met within a predetermined period of time, but a random access procedure for said candidate cells failing.

Also, the information about the reason for the failure is at least one of identification information of the candidate cell that was detected within the predetermined period in (b) and identification information of the candidate cell that satisfied the execution condition in the predetermined period in (c). may contain one.

In addition, the message may further include identification information of a cell other than the candidate cell and detected by the terminal 10 and/or information on the measurement result of the other cell.

The control unit 103 performs various controls in the terminal 10. Specifically, the control unit 103, based on information on the setting of the candidate cell (for example, the PSCell candidate setting information) and information on the execution condition of a specific procedure for the candidate cell (for example, the execution condition information) control the execution of that particular procedure (eg, CPAC).

The information on the execution condition (for example, the execution condition information) is an identifier of association information (for example, the above association identifier) (eg, FIG. 3). The control unit 103 may perform measurement based on the measurement target information, and determine whether or not the execution condition is satisfied based on the result of the measurement and the report information.

The control unit 103 may start a timer in response to the reception of the RRC reconfiguration message, and when the timer expires, remove the information regarding the configuration of the candidate cell and the information regarding the execution condition (for example, FIG. 5, 6). Also, when the timer expires, the control section 103 may remove at least one of the measurement target information, the report information, and the association information (eg, FIG. 3). Further, the control unit 103 may stop the timer when at least one execution condition of the candidate cell is satisfied.

≪Base station≫
FIG. 14 is a diagram showing an example of the functional block configuration of the base station according to this embodiment. As shown in FIG. 14, the base station 20 includes a receiver 201, a transmitter 202, and a controller 203. FIG.

All or part of the functions realized by the receiving unit 201 and the transmitting unit 202 can be realized using the communication device 13. All or part of the functions realized by the receiving unit 201 and the transmitting unit 202 and the control unit 203 can be realized by the processor 11 executing a program stored in the storage device 12 . Also, the program can be stored in a storage medium. The storage medium storing the program may be a computer-readable non-temporary storage medium. The non-temporary storage medium is not particularly limited, but may be a storage medium such as a USB memory or CD-ROM, for example.

The receiving unit 201 receives the upstream signal. Also, the receiving section 201 may receive information and/or data transmitted via the uplink signal. Specifically, when the execution of the specific procedure fails, the receiving unit 201 receives a message (eg, SCG failure information) containing information on the reason for the failure (eg, failure reason information) from the terminal 10. (eg, FIGS. 7 and 11).

Further, when operating as the base station 20 (eg, MN) associated with the first cell group, the receiving unit 201 receives each candidate cell from the second base station (eg, SN candidate) forming each candidate cell. (eg, PSCell candidate configuration information) and/or information (eg, execution condition information) regarding execution conditions of a specific procedure for each candidate cell. The information about the execution condition may be generated by the base station 20 without being received from the second base station.

The transmission unit 202 transmits the downlink signal. Also, the transmitting section 202 may transmit information and/or data transmitted via the downlink signal. Specifically, the transmitting unit 202 includes information regarding the configuration of one or more candidate cells (eg, PSCell candidate configuration information), information regarding execution conditions for a specific procedure for the candidate cell (eg, execution condition information), (eg, FIGS. 5, 6, 7, 11).

The transmitting unit 202 may transmit information on the reason for failure (eg, failure reason information) from the terminal 10 to other base stations (eg, SN candidates) forming candidate cells.

The control unit 203 performs various controls in the base station 20. The control unit 203 may control the above conditional procedure. When operating as a candidate (eg, SN candidate) for the base station 20 associated with the second cell group, the control unit 203 provides information on candidate cell configuration (eg, PSCell candidate configuration information) and/or for the candidate cell The generation of information (eg, execution condition information) regarding execution conditions for a particular procedure may be controlled. Also, when operating as the base station 20 (for example, MN) associated with the first cell group, the control section 203 may control generation of measurement configuration information regarding measurement configuration in the terminal 10 . The measurement configuration information may be included in the RRC reconfiguration message.

The control unit 203 may perform various controls based on information about the reason for failure (for example, failure reason information) from the terminal 10 .

(Other embodiments)
Various signals, information and parameters in the above embodiments may be signaled in any layer. That is, the above-mentioned various signals, information, parameters are higher layers (eg, Non Access Stratum (NAS) layer, RRC layer, MAC layer, etc.), lower layers (eg, physical layer), etc. Signals, information, may be replaced by parameters. Further, the notification of the predetermined information is not limited to being performed explicitly, but may be performed implicitly (for example, by not notifying the information or using other information).

Also, the names of various signals, information, parameters, IEs, channels, time units, and frequency units in the above embodiments are merely examples, and may be replaced with other names. For example, a slot may be named any unit of time having a predetermined number of symbols. Also, RB may be any name as long as it is a frequency unit having a predetermined number of subcarriers.

In addition, the use of the terminal 10 in the above embodiment (for example, for RedCap, IoT, etc.) is not limited to those illustrated, as long as it has similar functions, any use (for example, eMBB, URLLC, Device-to- Device (D2D), Vehicle-to-Everything (V2X), etc.). Also, the format of various information is not limited to the above embodiment, and may be appropriately changed to bit representation (0 or 1), true/false value (Boolean: true or false), integer value, character, or the like. Also, singularity and plurality in the above embodiments may be interchanged.

The embodiments described above are for facilitating understanding of the present disclosure, and are not for limiting interpretation of the present disclosure. Flowcharts, sequences, elements included in the embodiments, their arrangement, indexes, conditions, and the like described in the embodiments are not limited to those illustrated and can be changed as appropriate. Moreover, it is possible to partially replace or combine at least part of the configurations described in the above embodiments.

Claims (9)

1. a receiving unit for receiving an RRC reconfiguration message including information on configuration of one or more candidate cells and information on execution conditions of a specific procedure for the candidate cells;
   a control unit that controls execution of the specific procedure based on the information on the setting and the information on the execution condition;
   The control unit starts a timer in response to receiving the RRC reconfiguration message, and removes the information about the configuration and the information about the execution condition when the timer expires.
   terminal.
2. the execution condition information includes an identifier of association information relating to association between measurement target information related to the measurement target in the terminal and report information related to the measurement result report of the measurement target;
   The control unit performs measurement based on the measurement target information, and determines whether the execution condition is satisfied based on the result of the measurement and the report information.
   A terminal according to claim 1 .
3. The control unit removes at least one of the measurement target information, the report information, and the association information when the timer expires.
   A terminal according to claim 2.
4. The control unit stops the timer when the execution condition of at least one of the candidate cells is satisfied.
   A terminal according to any one of claims 1 to 3.
5. the RRC reconfiguration message includes information about the timer;
   A terminal according to any one of claims 1 to 4.
6. The receiving unit receives the RRC reconfiguration message from a first base station associated with a first cell group;
   The specific procedure is a procedure of adding the candidate cell as a primary cell of a second cell group, or a procedure of changing the primary cell to the candidate cell.
   A terminal according to any one of claims 1 to 5.
7. Information about the configuration and/or information about the execution condition is transmitted from a second base station forming the candidate cell of the primary cell of the second cell group to the first base station.
   A terminal according to claim 6.
8. a sending unit that, if execution of the specific procedure fails, sends a message containing information about the reason for the failure;
   8. A terminal according to any one of claims 1 to 7, further comprising:
9. a terminal receiving an RRC reconfiguration message including information on configuration of one or more candidate cells and information on execution conditions of a specific procedure for the candidate cells;
   the terminal controlling execution of the specific procedure based on the information about the setting and the information about the execution condition;
   The terminal starts a timer in response to receiving the RRC reconfiguration message, and removes the information about the configuration and the information about the execution condition when the timer expires.
   wireless communication method.

Images