Communication device, base station, and communication method

Abstract

A communication device (100) that performs communication with a primary cell group associated with a primary node and a secondary cell group associated with a secondary node, the communication device being provided with: a reception unit (112) that receives a radio resource control (RRC) message including a conditional primary-secondary (PS) cell change (CPC) configuration and determination information, the conditional primary-secondary (PS) cell change (CPC) configuration including a primary cell group associated with a primary node and a secondary cell group associated with a secondary node; the CPC configuration is a configuration of a PS cell, which is a primary cell of the secondary cell group, changed when an execution condition is satisfied, and the determination information is used for the communication device to determine whether to release the CPC configuration; and a control unit (120) that determines whether or not to release the CPC configuration on the basis of the determination information.

Description

[0001] Cross-references to related applications

[0002] This application is based on patent application No. 2022-159053 filed on September 30, 2022, and claims the benefit of priority, the entire contents of which are incorporated into this specification by reference. Technical Field

[0003] The present disclosure relates to a communication device, a base station, and a communication method used in a mobile communication system. Background Art

[0004] In a mobile communication system that complies with the technical specifications of 3GPP (registered trademark, hereinafter the same) (3rd Generation Partnership Project), which is a standardization project for mobile communication systems, dual connectivity (DC) is introduced. In DC, a user equipment communicates with a main cell group (MCG) and a secondary cell group (SCG), the MCG being associated with a main node (also referred to as a "main base station"), and the SCG being associated with a secondary node (also referred to as a "secondary base station").

[0005] In the technical specifications of 3GPP, provisions are made for the change of primary and secondary cells (PS cells). As one of the processes for changing PS cells, there is a conditional PS cell change (CPC) process. In the CPC process, the communication device performs a PS cell change when the execution conditions based on the configured CPC configuration (CPC configuration) are met. For example, it is possible to switch the secondary node from the source secondary node (first secondary node) to the target secondary node (second secondary node) without an instruction from the primary node. In the current technical specification, when the execution of the CPC process is successful, the communication device releases all CPC configurations stored in the communication device.

[0006] In recent years, for example, continuous cell changes have been discussed to enable continuous cell changes when a communication device moves at high speed. In order to achieve continuous cell changes, it is proposed that the network explicitly releases the CPC configuration configured for the communication device under the premise that the CPC configuration is not released even if the CPC process is successful (see non-patent document 1). As a result, it is possible to avoid reconfiguring the CPC configuration for the communication device, and even after the CPC process is successfully performed, the communication device can perform the CPC process based on the maintained CPC configuration.

[0007] Prior art literature

[0008] Non-patent literature

[0009] Non-patent document 1: 3GPP contribution document "R2-2208036 (Analysis of applicable scenarios and problems for NR-DC selective activation procedure)" Summary of the invention

[0010] The communication device involved in the first aspect is a communication device for communicating with a primary cell group and a secondary cell group, the aforementioned primary cell group is associated with a primary node, and the aforementioned secondary cell group is associated with a secondary node, the aforementioned communication device includes: a receiving unit, receiving a radio resource control (RRC) message, the aforementioned RRC message includes a conditional primary and secondary (PS) cell change (CPC) configuration and judgment information, the aforementioned CPC configuration is a configuration of a PS cell that is a primary cell of the aforementioned secondary cell group when an execution condition is met, and the aforementioned judgment information is used by the aforementioned communication device to determine whether to release the aforementioned CPC configuration; and a control unit, based on the aforementioned judgment information, to determine whether to release the aforementioned CPC configuration.

[0011] The second aspect involves a base station that acts as the aforementioned master node in a first network including a master node and a secondary node, the aforementioned master node is associated with a master cell group (MCG) configured for the communication device, the aforementioned secondary node is associated with a secondary cell group (SCG) configured for the aforementioned communication device, the aforementioned base station includes a sending unit, the aforementioned sending unit sends a radio resource control (RRC) message to the aforementioned communication device, the aforementioned RRC message includes a conditional primary and secondary (PS) cell change (CPC) configuration and determination information, the aforementioned CPC configuration is a configuration of a PS cell that changes the primary cell of the aforementioned secondary cell group when an execution condition is met, and the aforementioned determination information is used by the aforementioned communication device to determine whether to release the aforementioned CPC configuration.

[0012] The communication method involved in the third aspect is a communication method performed by a communication device, wherein the aforementioned communication device communicates with a primary cell group and a secondary cell group, the aforementioned primary cell group is associated with a primary node, and the aforementioned secondary cell group is associated with a secondary node, and the aforementioned communication method includes: a step of receiving a radio resource control (RRC) message, the aforementioned RRC message includes a conditional primary-secondary (PS) cell change (CPC) configuration and determination information, the aforementioned CPC configuration is a configuration of a PS cell that is a primary cell of the aforementioned secondary cell group when an execution condition is met, the aforementioned determination information is used by the aforementioned communication device to determine whether to release the aforementioned CPC configuration; and a step of determining whether to release the aforementioned CPC configuration based on the aforementioned determination information.

[0013] The second aspect involves a communication method performed by a base station, wherein the base station acts as the master node in a first network including a master node and a slave node, the master node is associated with a master cell group (MCG) configured for a communication device, and the slave node is associated with a secondary cell group (SCG) configured for the communication device, and the communication method includes the step of sending a radio resource control (RRC) message to the communication device, the RRC message includes a conditional primary-secondary (PS) cell change (CPC) configuration and determination information, the CPC configuration is a configuration change of the PS cell as the master cell of the secondary cell group when an execution condition is met, and the determination information is used by the communication device to determine whether to release the CPC configuration.

[0014] Effects of the Invention

[0015] According to one aspect of the present invention, a communication device, a base station, and a communication method capable of appropriately releasing CPC configuration can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The objects, features, advantages and the like of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.

[0017] Figure 1 It is a diagram showing the configuration of a mobile communication system involved in an embodiment.

[0018] Figure 2 It is a diagram showing a configuration example of a protocol stack in a mobile communication system according to an embodiment.

[0019] Figure 3 This is a diagram showing an overview of dual connectivity (DC) according to an embodiment.

[0020] Figure 4 It is a diagram showing the configuration of a user equipment (UE) involved in an embodiment.

[0021] Figure 5 It is a diagram showing the configuration of a base station involved in the embodiment.

[0022] Figure 6 It is a diagram showing an operation example of the mobile communication system involved in the embodiment.

[0023] Figure 7 It is a diagram showing a configuration example of an RRC reconfiguration message according to an embodiment.

[0024] Figure 8 It is a diagram showing a configuration example of an RRC reconfiguration message according to an embodiment.

[0025] Fig. 9It is a diagram showing an operation example of the UE involved in the implementation manner.

[0026] Fig.10 It is a diagram showing an operation example of the UE involved in the implementation manner.

[0027] Fig.11 It is a diagram showing an operation example of the UE involved in the implementation manner.

[0028] Fig.12 It is a diagram showing an operation example of the UE involved in the implementation manner. DETAILED DESCRIPTION

[0029] The mobile communication system according to the embodiment will be described with reference to the accompanying drawings. In the description of the drawings, the same or similar reference numerals are given to the same or similar parts.

[0030] Before the communication device receives a release instruction of the CPC configuration from the network, the CPC configuration must be continuously maintained, and there is a concern that the CPC configuration cannot be properly released.

[0031] Therefore, one of the objects is set to provide a communication device, a base station, and a communication method capable of appropriately releasing the CPC configuration.

[0032] (Configuration of mobile communication system)

[0033] Reference Figure 1 , the configuration of the mobile communication system 1 involved in the implementation mode is described. The mobile communication system 1 is, for example, a system that complies with the technical specification (Technical Specification: TS) of 3GPP. In the following, as the mobile communication system 1, a 5th generation system (5GS) of the 3GPP standard, that is, a mobile communication system based on NR (New Radio) is described as an example.

[0034] The mobile communication system 1 includes a network 10 and a user equipment (UE) 100 communicating with the network 10. The network 10 includes a NG-RAN (Next Generation Radio Access Network) 20 which is a 5G radio access network and a 5GC (5G Core Network) 30 which is a 5G core network.

[0035] UE 100 is an example of a communication device. UE 100 may be a device used by a user. UE 100 may be a user device specified in the technical specifications of 3GPP. UE 100 is, for example, a mobile phone terminal such as a smartphone, a tablet terminal, a notebook PC (personal computer), a communication module or a communication card, and other movable devices. UE 100 may be a vehicle (e.g., a car, a train, etc.) or a device set therein. UE 100 may be a transport body other than a vehicle (e.g., a ship, an airplane, etc.) or a device set therein. UE 100 may be a sensor or a device set therein. In addition, UE 100 may also be referred to as a mobile station, a mobile terminal, a mobile device, a mobile unit, a subscriber station, a subscriber terminal, a subscriber device, a subscriber unit, a wireless station, a wireless terminal, a wireless device, a wireless unit, a remote station, a remote terminal, a remote device, or a remote unit, and other names. In addition, UE 100 is an example of a terminal, and the terminal may include factory equipment, etc.

[0036] NG-RAN 20 includes multiple base stations 200. Each base station 200 manages at least one cell. A cell constitutes the smallest unit of a communication area. For example, a cell belongs to one frequency (carrier frequency) and includes one component carrier. The term "cell" sometimes refers to wireless communication resources and sometimes refers to the communication object of UE 100. Each base station 200 is capable of wireless communication with UE 100 located in this cell. The base station 200 communicates with UE 100 using the protocol stack of RAN. The base station 200 is connected to other base stations 200 (also referred to as neighboring base stations) via the Xn interface. The base station 200 communicates with neighboring base stations via the Xn interface. In addition, the base station 200 provides NR user plane and control plane protocol termination for UE 100, and is connected to 5GC 30 via the NG interface. Such an NR base station 200 is sometimes referred to as gNodeB (gNB).

[0037] 5GC 30 includes a core network device 300. The core network device 300 includes, for example, AMF (Access and Mobility Management Function) and / or UPF (User Plane Function). AMF performs mobility management of UE 100. UPF provides functions dedicated to user plane processing. AMF and UPF are connected to base station 200 via an NG interface.

[0038] Reference Figure 2 , an example of the configuration of the protocol stack in the mobile communication system 1 involved in the implementation scheme is described.

[0039] The protocol of the wireless section between UE 100 and base station 200 includes a physical (PHY) layer, a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, a PDCP (Packet Data Convergence Protocol) layer, and an RRC (Radio Resource Control) layer.

[0040] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the base station 200 via a physical channel.

[0041] A physical channel includes multiple OFDM symbols in the time domain and multiple subcarriers in the frequency domain. A subframe includes multiple OFDM symbols in the time domain. A resource block is a resource allocation unit, including multiple OFDM symbols and multiple subcarriers. A frame can be configured by 10ms and can include 10 subframes configured by 1ms. Within a subframe, a number of time slots corresponding to the subcarrier spacing can be included.

[0042] Among the physical channels, the physical downlink control channel (PDCCH) plays a core role in purposes such as downlink scheduling allocation, uplink scheduling permission, and transmission power control. For example, UE 100 uses the cell radio network temporary identifier (Cell-Radio Network Temporary Identifier: C-RNTI) and the modulation and coding scheme cell radio network temporary identifier (Modulation and CodingScheme-C-RNTI: MCS-C-RNTI), or the configured scheduling radio network temporary identifier (ConfiguredScheduling-RNTI: CS-RNTI) allocated to UE 100 from the base station 200 to perform blind decoding of the PDCCH, and obtains the successfully decoded DCI as the DCI sent to this UE. Here, in the DCI sent from the base station 200, a CRC parity bit scrambled by C-RNTI and MCS-C-RNTI, or CS-RNTI is added.

[0043] In NR, UE 100 can use a bandwidth narrower than the system bandwidth (i.e., the bandwidth of the cell). The base station 200 configures a bandwidth part (BWP) including continuous PRBs for UE 100. UE 100 sends and receives data and control signals in the active BWP. In UE 100, for example, up to four BWPs can be configured. Each BWP can have a different subcarrier spacing, and the frequencies can overlap with each other. In the case where multiple BWPs are configured for UE 100, the base station 200 can specify which BWP to activate through control in the downlink. As a result, the base station 200 can dynamically adjust the UE bandwidth according to the data traffic of UE 100, etc., which can reduce UE power consumption.

[0044] The base station 200 can configure up to three control resource sets (CORESETs) for each of up to four BWPs on the serving cell, for example. A CORESET is a radio resource used for control information that the UE 100 should receive. Up to 12 CORESETs can be configured on the serving cell for the UE 100. Each CORESET includes an index from 0 to 11. For example, a CORESET includes six resource blocks (PRBs) and one, two, or three consecutive OFDM symbols in the time domain.

[0045] The MAC layer performs data priority control, retransmission processing using hybrid ARQ (HARQ), and random access procedures. Data and control information are transmitted between the MAC layer of the UE 100 and the MAC layer of the base station 200 via a transmission channel. The MAC layer of the base station 200 includes a scheduler. The scheduler determines the transmission format (transmission block size, modulation and coding scheme (MCS)) of the uplink and downlink and the allocated resources to the UE 100.

[0046] The RLC layer transmits data to the RLC layer of the receiving side using the functions of the MAC layer and the PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the base station 200 via a logical channel.

[0047] The PDCP layer performs header compression / decompression and encoding / decoding.

[0048] The SDAP (Service Data Adaptation Protocol) layer can be set as the upper layer of the PDCP layer. The SDAP (Service Data Adaptation Protocol) layer maps IP flows and radio bearers: IP flows are the units for QoS (Quality of Service) control in the core network, and radio bearers are the units for QoS control in the AS (Access Stratum).

[0049] The RRC layer controls logical channels, transport channels, and physical channels in response to the establishment, reestablishment, and release of radio bearers. RRC signaling for various configurations is transmitted between the RRC layer of the UE 100 and the RRC layer of the base station 200. In the case where an RRC connection exists between the RRC of the UE 100 and the RRC of the base station 200, the UE 100 is in an RRC connected state. In the case where there is no RRC connection between the RRC of the UE 100 and the RRC of the base station 200, the UE 100 is in an RRC idle state. In the case where the RRC connection between the RRC of the UE 100 and the RRC of the base station 200 is suspended, the UE 100 is in an RRC inactive state.

[0050] The NAS layer located above the RRC layer performs session management and mobility management of UE 100. NAS signaling is transmitted between the NAS layer of UE 100 and the NAS layer of core network device 300 (AMF). In addition to the radio interface protocol, UE 100 also includes an application layer and the like.

[0051] (DC Overview)

[0052] Reference Figure 3 , an overview of dual connectivity (DC) according to an embodiment of the present invention is described.

[0053] In DC, UE 100 performs simultaneous communication with a master cell group (MCG) 201M managed by a master node (MN) 200M and a secondary cell group (SCG) 201S managed by a secondary node (SN) 200S. MN 200M may be an NR base station (gNB) or an LTE base station (eNB). MN 200M is also referred to as a master base station. SN 200S may be an NR base station (gNB) or an LTE base station (eNB). SN 200S is also referred to as a secondary base station.

[0054] For example, the MN 200M sends a predetermined message (eg, an SN Addition Request message) to the SN 200S, and the MN 200M sends an RRC Reconfiguration message to the UE 100, thereby starting the DC.

[0055] The UE 100 in the RRC connection state is allocated radio resources from the scheduler of each of the MN 200M and the SN 200S connected to each other via the network communication section of the backhaul, and uses the radio resources of the MN 200M and the radio resources of the SN 200S for wireless communication. The network communication section between the MN 200M and the SN 200 may be an Xn interface or an X2 interface. The MN 200M and the SN 200 communicate with each other via the network communication section.

[0056] MN 200M may have a control plane connection with a core network. MN 200M provides primary radio resources for UE 100. MN 200M manages MCG 201M. MCG 201M is a group of serving cells associated with MN 200M. MCG 201M includes a primary cell (PCell) and optionally one or more secondary cells (SCells).

[0057] The SN 200S may also not have a control plane connection with the core network. The SN 200S provides additional radio resources to the UE 100. The SN 200S manages the SCG 201S. The SCG is associated with the SN 200S. The SCG 201S includes a primary and secondary cell (PS cell), and optionally includes more than one SCell. In addition, the PCell of the MCG 201M and the PS cell of the SCG 201S are also referred to as special cells (SpCells).

[0058] In DC, the PS cell change of SCG 201S is sometimes performed. The MAC entity can be reset and the RLC entity of SCG 201S can be reestablished through the PS cell change. The SN 200S change process is sometimes performed through the PS cell change. For example, the SN 200S is changed from the source SN 200S1 (first secondary node) to the target SN 200S2 (second secondary node) through the PS cell change.

[0059] In the technical specifications of 3GPP, provisions are made for the change of primary and secondary cells (PS cells). As one of the processes for changing PS cells, there is a conditional PS cell change (CPC) process. In the CPC process, when the execution conditions based on the configured CPC configuration (CPC configuration) are met, the UE 100 performs a PS cell change. For example, it is possible to switch the secondary node from the source secondary node to the target secondary node without an instruction from the primary node. In the current technical specifications, when the execution of the CPC process is successful, the UE 100 releases all CPC configurations stored by the UE 100.

[0060] In recent years, for example, continuous cell changes have been discussed to enable continuous cell changes when the UE 100 moves at high speed. In order to achieve continuous cell changes, it is proposed that the network explicitly releases the CPC configuration configured for the UE 100 under the premise that the CPC configuration is not released even if the CPC procedure is successful. As a result, it is possible to avoid reconfiguring the CPC configuration for the UE 100, and even after the CPC procedure is successfully performed, the UE 100 can perform the CPC procedure based on the retained CPC configuration.

[0061] However, there is a concern that the CPC configuration cannot be properly released before UE 100 receives a release instruction for the CPC configuration from the network. In one embodiment described below, an operation for properly releasing the CPC configuration will be described.

[0062] (Configuration of user equipment)

[0063] Reference Figure 4 , the configuration of the UE 100 involved in the embodiment is described. The UE 100 includes a communication unit 110 and a control unit 120.

[0064] The communication unit 110 performs wireless communication with the base station 200 by sending and receiving wireless signals with the base station 200. The communication unit 110 includes at least one transmitting unit 111 and at least one receiving unit 112. The transmitting unit 111 and the receiving unit 112 can be configured to include multiple antennas and RF circuits. The antenna converts the signal into an electric wave and radiates the electric wave into space. In addition, the antenna receives the electric wave in the space and converts the electric wave into a signal. The RF circuit performs analog processing of the signal sent and received via the antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, etc.

[0065] The control unit 120 performs various controls in the UE 100. The control unit 120 controls the communication with the base station 200 via the communication unit 110. The above-mentioned and later-mentioned actions of the UE 100 may be actions controlled by the control unit 120. The control unit 120 may include at least one processor capable of executing a program and a memory storing the program. The processor may execute the program to perform the actions of the control unit 120. The control unit 120 may include a digital signal processor that performs digital processing of signals sent and received via an antenna and an RF circuit. The digital processing includes processing of a protocol stack of the RAN. In addition, the memory stores a program executed by the processor, parameters related to the program, and data related to the program. The memory may include at least one of a ROM (Read Only Memory), an EPROM (Erasable Programmable ReadOnly Memory), an EEPROM (Electrically Erasable ProgrammableRead Only Memory), a RAM (Random Access Memory), and a flash memory. All or a portion of the memory may be included within the processor.

[0066] In the UE 100 configured in this way, the receiving unit 112 receives a radio resource control (RRC) message, the RRC message including a conditional primary-secondary (PS) cell change (CPC) configuration and determination information, the CPC configuration being a configuration for changing a PS cell as a primary cell of a secondary cell group when an execution condition is satisfied, and the determination information being used by the UE 100 to determine whether to release the CPC configuration. The control unit 120 determines whether to release the CPC configuration based on the determination information. Thus, the UE 100 can appropriately discard the CPC configuration based on the determination information.

[0067] (Base station configuration)

[0068] Reference Figure 5 , the configuration of the base station 200 involved in the embodiment is described. The base station 200 includes a communication unit 210, a network communication unit 220, and a control unit 230.

[0069] The communication unit 210, for example, receives a wireless signal from the UE 100 and sends a wireless signal to the UE 100. The communication unit 210 includes at least one transmitting unit 211 and at least one receiving unit 212. The transmitting unit 211 and the receiving unit 212 may be configured to include an RF circuit. The RF circuit performs analog processing of signals sent and received via an antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, and the like.

[0070] The network communication unit 220 sends and receives signals with the network. The network communication unit 220 receives signals from, for example, an adjacent base station connected via an Xn interface as an interface between base stations, and sends signals to the adjacent base station. In addition, the network communication unit 220 receives signals from, for example, a core network device 300 connected via an NG interface, and sends signals to the core network device 300.

[0071] The control unit 230 performs various controls in the base station 200. The control unit 230 controls, for example, communication with the UE 100 via the communication unit 210. In addition, the control unit 230 controls, for example, communication with a node (e.g., a neighboring base station, a core network device 300) via the network communication unit 220. The actions of the base station 200 described above and below may be actions controlled by the control unit 230. The control unit 230 may include at least one processor capable of executing a program and a memory storing the program. The processor may execute the program to perform the actions of the control unit 230. The control unit 230 may include a digital signal processor that performs digital processing of signals sent and received via an antenna and an RF circuit. The digital processing includes processing of a protocol stack of the RAN. In addition, the memory stores a program executed by the processor, parameters related to the program, and data related to the program. All or part of the memory may be included in the processor.

[0072] In the base station 200 configured in this way, the transmitting unit 211 transmits a radio resource control (RRC) message to the UE 100. The RRC message includes a conditional primary-secondary (PS) cell change (CPC) configuration and determination information. The CPC configuration is a configuration for changing a PS cell as a primary cell of a secondary cell group when an execution condition is satisfied. The determination information is used for the UE 100 to determine whether to release the CPC configuration. Thus, the UE 100 can appropriately discard the CPC configuration based on the determination information.

[0073] (Operation Example of Mobile Communication System)

[0074] Reference Figure 6 , an operation example of the mobile communication system 1 involved in the embodiment is described. In addition, it is assumed that Figure 6Before the illustrated process starts, DC is configured through UE 100, MN 200M, and source SN 200S1.

[0075] In step S10, the control unit 120 of the UE 100 generates a measurement report (Measurement Report) including measurement results for each cell, and sends the measurement report to the MN 200M from the sending unit 211. For example, the UE 100 sends the measurement report in response to the conditions that the received signal strength from the cell of the source SN 200S1 becomes lower than a threshold, and the received signal strength from the cell of the target SN 200S2 becomes higher than a threshold.

[0076] In step S11, the control unit 230 of the MN 200M generates an SN Addition Request message in response to the measurement report received by the receiving unit 212, and transmits the SN Addition Request message from the network communication unit 220 to the target SN 200S2.

[0077] In step S12, the control unit 230 of the target SN 200S2 generates an SN Addition Request Acknowledgement message in response to the network communication unit 220 receiving the SN Addition Request message, and transmits the SN Addition Request Acknowledgement message from the network communication unit 220 to the MN 200M.

[0078] In step S13, the control unit 230 of the MN 200M generates an SN Release Request message in response to receiving the N Add Request Acknowledgement from the network communication unit 220, and transmits the SN Release Request message from the network communication unit 220 to the source SN 200S1.

[0079] In step S14, the control unit 230 of the source SN 200S1 generates an SN Release Request ACK message in response to receiving the SN Release Request message from the network communication unit 220, and sends the SN Release Request ACK message from the network communication unit 220 to the MN 200M.

[0080] In step S15 , in response to receiving the SN release request confirmation message from the network communication unit 220 , the control unit 230 of the MN 200M generates an RRC Reconfiguration message for conditional PS cell change, and transmits the RRC Reconfiguration message from the transmission unit 211 to the UE 100 .

[0081] The RRC reconfiguration message includes a conditional PS cell change (CPC) configuration and determination information. The CPC configuration is to change the configuration of the PS cell when an execution condition is met. The determination information is used by the UE 100 to determine whether to release the CPC configuration.

[0082] CPC configuration (eg, conditionalReconfiguration) may be conditional handover (CHO), conditional PS cell addition (CPA), or configuration of candidate target Sp cells for CPC and execution conditions.

[0083] The determination information may be information for configuring the presence or absence of release of the CPC configuration to the UE 100. The determination information may include at least any one of an indicator indicating whether to release the CPC configuration after the PS cell is changed, number information indicating the number of times the UE 100 maintains the CPC configuration, timer information indicating the period for which the UE 100 maintains the CPC configuration, and event information indicating a condition for releasing the CPC configuration.

[0084] like Figure 7 As shown, the decision information may be associated with each CPC configuration, for example, included in an RRC reconfiguration message. The CPC configuration may be associated by the location where the decision information is stored, based on which the CPC configuration is released.

[0085] The control unit 120 may configure the determination information for each SCG, for example, when the determination information is associated with the configuration for multiple SCGs in the RRC reconfiguration message. Therefore, the control unit 120 may adapt the determination result to all execution conditions configured for each corresponding SCG, for example.

[0086] For example, by Figure 7 The object of the determination information (eg, confidurationReleaseIndicator) shown in E1 may be a Figure 7 Similarly, Figure 7 The object of the determination information (eg, confidurationReleaseIndicator) shown in E2 may be a Figure 7 The information shown in E2a. Figure 7 The same is true for the determination information shown in E3. Figure 7 In the embodiment, the control unit 120 may determine whether to release the CPC configuration based on the determination information. The CPC configuration is the CPC configuration of the SCG configured for the UE 100 and is associated with the determination information in the RRC reconfiguration message.

[0087] The control unit 120 may configure the determination information for each execution condition, for example, when the determination information is associated with the configuration for each SCG in the RRC reconfiguration message. Therefore, the control unit 120 may adapt the determination result to each corresponding execution condition, for example.

[0088] For example, Figure 8 As shown, the control unit 120 can determine whether to release the CPC configuration based on the determination information. The aforementioned CPC configuration is a CPC configuration associated with the determination information among the CPC configurations configured for the UE 100.

[0089] In addition, the control unit 120 may, for example, adapt the determination result to the execution conditions for all cell groups configured in the RRC reconfiguration message when the determination condition is directly configured in the RRC reconfiguration message. For example, when the determination information is stored in parallel with the RRC reconfiguration (RRCReconfiguration-IEs), the control unit 120 may determine whether to release all CPC configurations configured for the UE 100 based on the determination information.

[0090] Furthermore, the determination information can predetermine the object to which the determination information is applied regardless of the storage location.

[0091] In addition, the RRC reconfiguration message may include a list of SCG configurations (e.g., mrdc-SecondaryCellGrouToAddModList), which is used to configure multiple SCG candidates including PS cell candidates. In addition, the SCG configuration is information for configuring multiple SCG (inter-SCG) candidates associated with each target SN 200S2. Figure 7 As shown, the list may include a set (mrdc-SecondaryCellGrouToAddMod) corresponding to an SCG configuration (e.g., nr-SCG) and a cell group configuration identifier (e.g., cellGroupConfigId).

[0092] In step S16, the control unit 120 of the UE 100 performs RRC reconfiguration in response to the reception of the RRC reconfiguration message by the reception unit 112, generates an RRC Reconfiguration Complete message, and transmits the RRC Reconfiguration Complete message from the transmission unit 111 to the MN 200M.

[0093] After the RRC reconfiguration, the control unit 120 of the UE 100 performs downlink synchronization (and downlink measurement) with respect to the target SN 200S2 (target PSCell) based on .

[0094] In step S17, the control unit 120 of the UE 100 performs measurement on each candidate cell based on the CPC configuration, and performs random access to the target SN 200S2 (target PSCell) when the execution conditions based on the CPC configuration are met. By performing such a random access process, the UE 100 performs connection processing on the target SN 200S2 (target PSCell) and completes the change of the PS cell.

[0095] The control unit 120 of the UE 100 may execute the process of step S18 when the change of the PS cell is completed. The control unit 120 may execute the process of step S18 when the change of the normal PS cell and / or the change of the conditional PS cell is completed.

[0096] In step S18, the control unit 120 of the UE 100 determines whether to release the CPC configuration based on the determination information. The control unit 120 may perform at least any one of the following actions.

[0097] (A) Indicator

[0098] In the case where the determination information includes an indicator, such as Fig. 9 As shown, the control unit 120 can determine whether to release the CPC configuration. In step S111, if the indicator indicates the release of the CPC configuration, the control unit 120 performs the process of step S112. On the other hand, if the indicator does not indicate the release of the CPC configuration, the control unit 120 performs the process of step S113.

[0099] The indicator explicitly indicates whether to release the CPC configuration. The indicator can indicate to release the CPC configuration or to maintain the CPC configuration.

[0100] In step S112, the control unit 120 releases the CPC configuration. In this case, the control unit 120 may discard the CPC configuration. The control unit 120 may release the CPC configuration after the PS cell change is successful. The control unit 120 may release the CPC configuration associated with the indicator.

[0101] In step S113, the control unit 120 holds the CPC configuration. In this case, the control unit 120 may hold the CPC configuration or store the CPC configuration. The control unit 120 may hold the CPC configuration associated with the indicator.

[0102] (B) Frequency information

[0103] In the case where the determination information includes the number of times information, such as Fig.10As shown, the control unit 120 can determine whether to release the CPC configuration. In step S121, the control unit 120 can determine whether the number of changes of the PS cell is greater than or equal to a predetermined number indicated by the number information.

[0104] If the number of PS cell changes is greater than the number of changes based on the number information, the control unit 120 performs the process of step S122. On the other hand, if the number of PS cell changes is less than the number of changes based on the number information, the control unit 120 performs the process of step S123.

[0105] The control unit 120 may perform the following processing to count the number of changes in the PS cell. The control unit 120 configures a counter (e.g., nonRelease_COUNTER) in the MAC layer, and the counter counts the number of successful RA procedures in the PS cell change. The control unit 120 sets the initial value of the count value to 0. Each time the RA procedure in the PS cell change is successful, the control unit 120 increases the counter by 1. The control unit 120 compares the counter with a predetermined number of times (e.g., nonRelease_MaxCount) indicated by the number information. When the counter is greater than the predetermined number of times, the control unit 120 performs the processing of step S122. Alternatively, the control unit 120 may perform the processing of step S122 when the PS cell is changed after the counter is greater than the predetermined number of times.

[0106] In addition, the RRC reconfiguration message (or determination information) may include information indicating a configuration value of a predetermined timer. The control unit 120 may start a predetermined timer when the initial value of the counter is set to 0 in the MAC layer. The control unit 120 may reset the counter and perform the process of step S122 when the predetermined timer expires. The control unit 120 may perform the process of step S122 regardless of the number of changes of the PS cell when the predetermined timer expires. The control unit 120 may perform the process of step S122 when the PS cell is changed after the predetermined timer expires.

[0107] Steps S122 and S123 are the same as steps S112 and S113.

[0108] (C) Timer information

[0109] In the case where the determination information includes timer information, such as Fig.11 As shown, the control unit 120 can determine whether to release the CPC configuration. In step S131, the control unit 120 can determine whether the holding timer has expired.

[0110] If the hold timer has expired, the control unit 120 executes the process of step S132. On the other hand, if the hold timer has not expired, the control unit 120 executes the process of step S133.

[0111] For example, when performing the initial measurement (determination), the control unit 120 starts the retention timer. When the PS cell is changed during the operation of the retention timer, the control unit 120 retains the CPC configuration associated with the retention timer during the operation. The control unit 120 may also restart the retention timer associated with the CPC configuration used to change the PS cell.

[0112] The control unit 120 may immediately execute the process of step S132 when the hold timer expires. The control unit 120 may execute the process of step S132 when the PS cell is changed after the hold timer expires.

[0113] (D) Event Information

[0114] In the case where the determination information includes event information, such as Fig.12 As shown, the control unit 120 can determine whether to release the CPC configuration. In step S141, the control unit 120 can determine whether the release condition is satisfied.

[0115] If the release condition is satisfied, the control unit 120 executes the process of step S142. On the other hand, if the release condition is not satisfied, the control unit 120 executes the process of step S143.

[0116] The event information may configure a new event (e.g., CondEvent R1) as an execution condition (release condition) as an event used in a measurement report. The event information may include, for example, a threshold value (r1-threashold). The threshold value may be configured by MN200M, by the source SN 200S1, or by the target SN 200S2. The control unit 120 may configure the threshold value and perform measurements while referring to the threshold value.

[0117] For example, when the measurement result of the measurement object is above a threshold (or greater than a threshold), the control unit 120 may maintain the CPC configuration (for example, the configuration associated with the measurement identifier (MeasID) configured for the measurement object (for example, the measObjectID configured in association with CondEvent R1) until the next measurement timing.

[0118] For example, the control unit 120 may perform the process of step S142 for a CPC configuration (e.g., a configuration associated with a measurement identifier (MeasID) configured for the same measurement object identifier (measObjectID)) when the measurement result of the measurement object is less than a threshold value (or is below the threshold value), wherein the CPC configuration is a CPC configuration configured for the measurement object (e.g., a measurement object identifier (measObjectID) configured in association with a release condition (e.g., CondEvent R1)). Alternatively, the control unit 120 may perform the process of step S142 for the CPC configuration when the PS cell is changed.

[0119] As described above, the transmitting unit 211 of the MN 200M receives the RRC message including the CPC configuration and the determination information. The receiving unit 112 of the UE 100 receives the RRC message including the CPC configuration and the determination information. The control unit 120 determines whether to release the CPC configuration based on the determination information. Thus, the UE 100 can appropriately release the CPC configuration even if it does not receive the signaling for releasing the CPC configuration from the network 10.

[0120] In addition, the determination information may include an indicator indicating whether to release the CPC configuration after the PS cell is changed. When the indicator indicates the release of the CPC configuration, the control unit 120 may release the CPC configuration. Thus, the control unit 120 can release the CPC configuration appropriately because it is explicitly instructed whether the CPC configuration should be released.

[0121] In addition, when the indicator indicates to maintain the CPC configuration, the control unit 120 may maintain the CPC configuration without releasing it. Thus, the control unit 120 can maintain the CPC configuration that has not been instructed to be released by the network 10.

[0122] In addition, the determination information may include number information indicating the number of times the CPC configuration is maintained by the UE 100. The control unit 120 may maintain the CPC configuration until the number of changes in the SCell is greater than the number based on the number information. Thus, the control unit 120 is easy to continuously change the cell based on the maintained CPC configuration until the number is greater than the number based on the number information.

[0123] The control unit 120 may release the CPC configuration when the PS cell is changed after the number of PS cell changes is greater than the number based on the number information. For example, when the UE 100 frequently changes the PS cell, the execution condition of the CPC configuration may be inappropriate. The UE 100 can release the CPC configuration.

[0124] In addition, the control unit 120 may release the CPC configuration when the predetermined timer expires, regardless of the number of PS cell changes. The RRC message may include information indicating the configuration value of the predetermined timer. Thus, it is possible to prevent the UE 100 from maintaining the CPC configuration for a long time.

[0125] In addition, the determination information may include timer information indicating a period for which the UE 100 maintains the CPC configuration. The control unit 120 may maintain the CPC configuration until a retention timer configured based on the timer information expires. This can prevent the UE 100 from maintaining the CPC configuration for a long time.

[0126] In addition, the control unit 120 may release the CPC configuration when the retention timer configured based on the timer information expires. Thus, the UE 100 can avoid the UE 100 retaining the CPC configuration for a long time.

[0127] In addition, the control unit 120 may release the CPC configuration when the PS cell is changed after the holding timer configured based on the timer information expires. Thus, even if the holding timer expires, the UE 100 can easily change cells continuously.

[0128] In addition, the determination information may include event information indicating a condition for releasing the CPC configuration. The control unit 120 may maintain the CPC configuration until the condition is satisfied. Thus, the UE 100 can easily and continuously change cells until the condition is satisfied.

[0129] In addition, the determination information may include event information indicating a condition for releasing the CPC configuration. The control unit 120 may release the CPC configuration when the condition is satisfied. Thus, the UE 100 can appropriately release the CPC configuration.

[0130] The control unit 120 may release the CPC configuration when the PS cell is changed after the condition is satisfied. The UE 100 can release the CPC configuration appropriately.

[0131] In addition, the control unit 120 can determine whether to release all CPC configurations configured for the UE 100 based on the determination information. Thereby, the control unit 120 can easily manage each CPC configuration.

[0132] In addition, the control unit 120 can determine whether to release the CPC configuration based on the determination information, wherein the CPC configuration is the CPC configuration for the SCG associated with the determination information in the RRC message among the SCGs configured for the UE 100. Thus, the UE 100 can flexibly determine whether to release the CPC configuration associated with the SCG.

[0133] In addition, control unit 120 may determine whether to release the CPC configuration based on the determination information, which is the CPC configuration associated with the determination information in the RRC message among the CPC configurations configured for UE 100. Thus, UE 100 can flexibly determine whether to release each CPC configuration.

[0134] The RRC message may include a list of SCG configurations, which is used to configure multiple SCG candidates including PS cell candidates. Thus, since multiple SCG candidates are configured for UE 100, it is easy to change cells continuously. In addition, UE 100 can centrally manage information related to multiple SCG candidates.

[0135] [Other embodiments]

[0136] In the above implementation, the UE 100 determines whether to release the CPC configuration based on one determination information, but the present invention is not limited thereto. The UE 100 may determine whether to release the CPC configuration based on multiple types of determination information.

[0137] For example, when the determination information includes the first information and the second information, the first information includes the indicator, and the second information is different from the indicator (for example, at least any one of the number of times information, timer information, and event information), the control unit 120 may release the CPC configuration even if the indicator indicates that the CPC configuration is to be maintained when it is determined based on the second information. In addition, when the indicator indicates that the CPC configuration is to be maintained, when it is determined based on the second information that the CPC configuration is to be released, the corresponding indicator may be deleted.

[0138] In addition, the determination information may include first information and second information, the first information includes number information, and the second information is different from the number information (for example, at least one of an indicator, timer information, and event information). The control unit 120 may release the CPC configuration even if the number information indicates that the CPC configuration is maintained, when it is determined based on the second information that the CPC configuration is released. In addition, when the counter based on the number information indicates that the CPC configuration is maintained, when it is determined based on the second information that the CPC configuration is released, it may be determined that the corresponding counter is greater than a predetermined number of times.

[0139] In addition, the determination information may include first information and second information, the first information includes timer information, and the second information is different from the timer information (for example, at least any one of an indicator, number information, and event information). The control unit 120 may release the CPC configuration even if the timer information indicates that the CPC configuration is to be maintained when it is determined based on the second information that the CPC configuration is to be released. In addition, when it is determined based on the second information that the CPC configuration is to be released while the maintenance timer indicates that the CPC configuration is to be maintained, the corresponding maintenance timer may be deemed to have expired.

[0140] In addition, the determination information may include first information and second information, the first information includes event information, and the second information is different from the number information (for example, at least one of the indicator, the number information, and the timer information). The control unit 120 may release the CPC configuration even if the event information indicates that the CPC configuration is maintained, when it is determined based on the second information that the CPC configuration is released. In addition, when the event information indicates that the CPC configuration is maintained, when it is determined based on the second information that the CPC configuration is released, the corresponding release condition may be considered to be satisfied.

[0141] In this way, it is possible to configure the determination information to be preferentially applied among the multiple types of determination information. By determining whether to release the CPC configuration based on multiple determination information, the release of the CPC configuration can be flexibly configured.

[0142] In the above-mentioned embodiment, the case where the RRC reconfiguration message includes the determination information is described, but the determination information may also be included in other RRC messages.

[0143] The action sequence (and action flow) in the above-mentioned embodiment may not necessarily be executed in chronological order along the order recorded in the flowchart or sequence diagram. For example, the steps in the action may be executed in an order different from the order recorded as a flowchart or sequence diagram, or may be executed in parallel. In addition, a part of the steps in the action may be deleted, or further steps may be added in the process. In addition, the action sequence (and action flow) in the above-mentioned embodiment may be implemented independently, or may be implemented by combining two or more action sequences (and action flows). For example, a part of the steps in an action flow may be added to other action flows, or a part of the steps in an action flow may be replaced by a part of the steps in other action flows.

[0144] In the above embodiment, as the mobile communication system 1, an NR-based mobile communication system is taken as an example for explanation. However, the mobile communication system 1 is not limited to this example. The mobile communication system 1 may be a TS system that complies with LTE (Long Term Evolution) or any other generation system (e.g., 6th generation) of the 3GPP standard. The base station 200 may be, for example, an eNB that provides an E-UTRA user plane and control plane protocol termination for the UE 100 in LTE. The mobile communication system 1 may also be a TS system that complies with a standard other than the 3GPP standard. The base station 200 may be an IAB (Integrated Access and Backhaul) host or an IAB node.

[0145] A program that enables a computer to execute each process performed by UE 100 or base station 200 may also be provided. The program may be recorded in a computer-readable medium. Using a computer-readable medium, the program can be installed in a computer. Here, the computer-readable medium on which the program is recorded may also be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, but may be a recording medium such as a CD-ROM (Compact Disk Read Only Memory) or a DVD-ROM (Digital Versatile Disc Read Only Memory). In addition, the circuits that execute each process performed by UE 100 or base station 200 may be integrated, and at least a portion of UE 100 or base station 200 may be configured as a semiconductor integrated circuit (chip set, SoC (System On Chip)).

[0146] In the above-mentioned embodiment, "transmit" may refer to processing at least one layer in the protocol stack for transmission, or may refer to physically sending a signal wirelessly or by wire. Alternatively, "transmit" may also refer to a combination of processing at least one layer and physically sending a signal wirelessly or by wire. Similarly, "receive" may refer to processing at least one layer in the protocol stack for reception, or may refer to physically receiving a signal wirelessly or by wire. Alternatively, "receive" may also refer to a combination of processing at least one layer and physically receiving a signal wirelessly or by wire. Similarly, "obtain / acquire" may refer to obtaining information from stored information, or may refer to obtaining information from information received by other nodes, or may refer to obtaining the information by generating information. Similarly, unless otherwise explicitly stated, the statement "based on" or "depending on / in response to" does not mean "based only on" or "based only on". The statement "based on" refers to both "based only on" and "based at least in part on". Similarly, the record of "in response to" refers to both "only in response to" and "at least partially in response to". Similarly, "include" and "comprise" do not refer to only including the listed items, but refer to only including the listed items, or other items in addition to the listed items. Similarly, in the present disclosure, "or" does not refer to logical XOR, but to logical OR. Furthermore, any reference to elements using the "first", "second" and other titles used in the present disclosure does not generally limit the amount or order of these elements. These titles can be used as a convenient method to distinguish between more than two elements in the present disclosure. Therefore, the reference to the first element and the second element does not mean that only two elements can be adopted therein, or that the first element must precede the second element in some form. In the present disclosure, for example, in the case where articles such as a, an and the in English are added by translation, these articles can include multiple, unless the context clearly indicates that multiple are not included.

[0147] It is understood that although the present disclosure is described according to the embodiments, the present disclosure is not limited to the embodiments or configurations. The present disclosure also includes various modifications and variations within the equivalent scope. In addition, various combinations, modes, and other combinations and modes including only one element, more or less elements in them also fall within the scope and thought of the present disclosure.

[0148] (Note)

[0149] Features related to the above-mentioned embodiment are supplementally noted.

[0150] (Note 1)

[0151] A communication device is a communication device (100) for communicating with a primary cell group and a secondary cell group, wherein the primary cell group is associated with a primary node, and the secondary cell group is associated with a secondary node, and the communication device comprises:

[0152] a receiving unit (112) for receiving a radio resource control (RRC) message, the RRC message including a conditional primary and secondary cell (PS) cell change (CPC) configuration and determination information, the CPC configuration being a configuration for changing a PS cell as a primary cell of the secondary cell group when an execution condition is satisfied, the determination information being used by the communication device to determine whether to release the CPC configuration; and

[0153] The control unit (120) determines whether to release the CPC configuration based on the determination information.

[0154] (Note 2)

[0155] According to the communication device described in Supplement 1, the determination information includes an indicator indicating whether to release the CPC configuration after changing the PS cell.

[0156] When the indicator indicates the release of the CPC configuration, the control unit releases the CPC configuration.

[0157] (Note 3)

[0158] According to the communication device of Supplement 1 or 2, the determination information includes an indicator indicating whether to release the CPC configuration after changing the PS cell.

[0159] In a case where the indicator indicates maintenance of the CPC configuration, the control unit maintains the CPC configuration without releasing it.

[0160] (Note 4)

[0161] According to the communication device described in Supplement 2 or 3, the determination information includes first information and second information, the first information includes the indicator, and the second information is different from the indicator.

[0162] When the control unit determines that the CPC configuration is to be released based on the second information, the control unit releases the CPC configuration even if the indicator indicates that the CPC configuration is to be maintained.

[0163] (Note 5)

[0164] The communication device according to any one of Annexes 1 to 4, wherein the determination information includes number information indicating the number of times the communication device maintains the CPC configuration.

[0165] The control unit maintains the CPC configuration until the number of changes in the PS cell is greater than or equal to the number based on the number information.

[0166] (Note 6)

[0167] According to the communication device described in Supplementary Note 5, when the number of changes of the PS cell is greater than or equal to the number based on the number information, the control unit releases the CPC configuration.

[0168] (Note 7)

[0169] According to the communication device described in Supplementary Note 5 or 6, when the PS cell is changed after the number of changes of the PS cell is equal to or greater than the number based on the number information, the control unit releases the CPC configuration.

[0170] (Note 8)

[0171] According to any one of Annexes 5 to 7, when a predetermined timer expires, the control unit releases the CPC configuration regardless of the number of changes of the PS cell.

[0172] The aforementioned RRC message includes information indicating a configuration value of the aforementioned predetermined timer.

[0173] (Note 9)

[0174] According to any one of Annexes 5 to 8, the aforementioned determination information includes first information and second information, the aforementioned first information includes the aforementioned number of times information, and the aforementioned second information is different from the aforementioned number of times information,

[0175] When the control unit determines that the CPC configuration is to be released based on the second information, the control unit releases the CPC configuration even if the number of times information indicates that the CPC configuration is to be maintained.

[0176] (Note 10)

[0177] The communication device according to any one of Annexes 1 to 9, wherein the determination information includes timer information indicating a period for which the communication device maintains the CPC configuration.

[0178] The aforementioned control unit maintains the aforementioned CPC configuration until a holding timer configured based on the aforementioned timer information expires.

[0179] (Note 11)

[0180] According to the communication device described in Supplementary Note 10, the control unit releases the CPC configuration when a holding timer configured based on the timer information expires.

[0181] (Note 12)

[0182] According to the communication device described in Supplementary Note 10 or 11, when the PS cell is changed after the retention timer configured based on the timer information expires, the control unit releases the CPC configuration.

[0183] (Note 13)

[0184] According to any one of supplementary notes 10 to 12, the determination information includes first information and second information, the first information includes the timer information, and the second information is different from the timer information.

[0185] When the control unit determines that the CPC configuration is to be released based on the second information, the control unit releases the CPC configuration even if the timer information indicates that the CPC configuration is to be maintained.

[0186] (Note 14)

[0187] The communication device according to any one of Annexes 1 to 13, wherein the determination information includes event information indicating a condition for releasing the CPC configuration.

[0188] The control unit maintains the CPC configuration until the conditions are met.

[0189] (Note 15)

[0190] The communication device according to any one of Annexes 1 to 14, wherein the determination information includes event information indicating a condition for releasing the CPC configuration.

[0191] When the aforementioned conditions are met, the aforementioned control unit releases the aforementioned CPC configuration.

[0192] (Note 16)

[0193] According to the communication device described in Supplementary Note 15, when the PS cell is changed after the above-mentioned condition is satisfied, the above-mentioned control unit releases the above-mentioned CPC configuration.

[0194] (Note 17)

[0195] According to any one of Annexes 14 to 16, the aforementioned determination information includes first information and second information, the aforementioned first information includes the aforementioned event information, and the aforementioned second information is different from the aforementioned number of times information.

[0196] When the control unit determines that the CPC configuration is to be released based on the second information, the control unit releases the CPC configuration even if the event information indicates that the CPC configuration is to be maintained.

[0197] (Note 18)

[0198] According to any one of Supplementary Notes 1 to 17, the control unit determines whether to release all CPC configurations configured for the communication device based on the determination information.

[0199] (Note 19)

[0200] According to the communication device described in any one of Notes 1 to 18, the aforementioned control unit determines whether to release the CPC configuration based on the aforementioned determination information, and the aforementioned CPC configuration is the CPC configuration of the SCG configured for the aforementioned communication device and the SCG associated with the aforementioned determination information in the aforementioned RRC message.

[0201] (Note 20)

[0202] According to any one of the communication devices described in Notes 1 to 19, the aforementioned control unit determines whether to release the CPC configuration based on the aforementioned determination information, and the aforementioned CPC configuration is a CPC configuration configured for the aforementioned communication device and is associated with the aforementioned determination information in the aforementioned RRC message.

[0203] (Note 21)

[0204] According to the communication device described in any one of Notes 1 to 20, the aforementioned RRC message includes a list of SCG configurations, and the aforementioned list is used to configure multiple SCG candidates including candidates of the aforementioned PS cell.

[0205] (Note 22)

[0206] A base station is a base station (200M) that acts as the master node in a first network including a master node and a slave node, the master node is associated with a master cell group (MCG) configured for a communication device (100), and the slave node is associated with a secondary cell group (SCG) configured for the communication device.

[0207] The aforementioned base station includes a sending unit (211), and the aforementioned sending unit sends a radio resource control (RRC) message to the aforementioned communication device. The aforementioned RRC message includes a conditional primary and secondary (PS) cell change (CPC) configuration and judgment information. The aforementioned CPC configuration is to change the configuration of the PS cell as the primary cell of the aforementioned secondary cell group when the execution condition is met. The aforementioned judgment information is used by the aforementioned communication device to determine whether to release the aforementioned CPC configuration.

[0208] (Note 23)

[0209] A communication method is a communication method performed by a communication device (100), wherein the communication device communicates with a primary cell group and a secondary cell group, wherein the primary cell group is associated with a primary node, and the secondary cell group is associated with a secondary node, and the communication method comprises:

[0210] receiving a radio resource control (RRC) message, the RRC message including a conditional primary-secondary (PS) cell change (CPC) configuration and determination information, the CPC configuration being a configuration for changing a PS cell as a primary cell of the secondary cell group when an execution condition is satisfied, the determination information being used by the communication device to determine whether to release the CPC configuration; and

[0211] Based on the aforementioned determination information, determine whether to release the aforementioned CPC configuration.

[0212] (Note 24)

[0213] A communication method is a communication method performed by a base station (200M), wherein the base station acts as the master node in a first network including a master node and a slave node, the master node is associated with a master cell group (MCG) configured for a communication device (100), and the slave node is associated with a secondary cell group (SCG) configured for the communication device.

[0214] The aforementioned communication method includes the step of sending a radio resource control (RRC) message to the aforementioned communication device, the aforementioned RRC message including a conditional primary-secondary (PS) cell change (CPC) configuration and determination information, the aforementioned CPC configuration is to change the configuration of the PS cell which is the primary cell of the aforementioned secondary cell group when the execution condition is met, and the aforementioned determination information is used by the aforementioned communication device to determine whether to release the aforementioned CPC configuration.

Claims

1. A communication device, which is a communication device (100) for communicating with a primary cell group and a secondary cell group, wherein the primary cell group is associated with a primary node, and the secondary cell group is associated with a secondary node, and the communication device comprises: A receiving unit (112) receives a radio resource control RRC message, the RRC message including a conditional primary and secondary PS cell change CPC configuration and determination information, the CPC configuration is a configuration of a PS cell that is a primary cell of the secondary cell group when an execution condition is met, and the determination information is used by the communication device to determine whether to release the CPC configuration; as well as The control unit (120) determines whether to release the CPC configuration based on the determination information.

2. The communication device according to claim 1, The determination information includes an indicator indicating whether to release the CPC configuration after changing the PS cell, In a case where the indicator indicates release of the CPC configuration, the control unit releases the CPC configuration.

3. The communication device according to claim 1 or 2, The determination information includes an indicator indicating whether to release the CPC configuration after changing the PS cell, In a case where the indicator indicates maintenance of the CPC configuration, the control section maintains the CPC configuration without releasing it.

4. The communication device according to claim 2, The determination information includes first information and second information, the first information includes the indicator, and the second information is different from the indicator, When the control unit determines to release the CPC configuration based on the second information, the control unit releases the CPC configuration even if the indicator indicates to maintain the CPC configuration.

5. The communication device according to claim 1 or 2, The determination information includes number information indicating the number of times the communication device maintains the CPC configuration, The control unit maintains the CPC configuration until the number of changes of the PS cell is greater than or equal to the number based on the number information.

6. The communication device according to claim 5, When the number of changes of the PS cell is greater than or equal to the number based on the number information, the control unit releases the CPC configuration.

7. The communication device according to claim 5, When the PS cell is changed after the number of changes of the PS cell is equal to or larger than a number based on the number information, the control unit releases the CPC configuration.

8. The communication device according to claim 5, When a predetermined timer expires, the control unit releases the CPC configuration regardless of the number of changes of the PS cell. The RRC message includes information indicating a configuration value of the predetermined timer.

9. The communication device according to claim 5, The determination information includes first information and second information, the first information includes the number of times information, and the second information is different from the number of times information, When the control unit determines to release the CPC configuration based on the second information, the control unit releases the CPC configuration even if the number of times information indicates to maintain the CPC configuration.

10. The communication device according to claim 1 or 2, The determination information includes timer information indicating a period for which the communication device maintains the CPC configuration, The control section maintains the CPC configuration until a holding timer configured based on the timer information expires.

11. The communication device according to claim 10, The control unit releases the CPC configuration when a holding timer configured based on the timer information expires.

12. The communication device according to claim 10, When the PS cell is changed after the holding timer configured based on the timer information expires, the control unit releases the CPC configuration.

13. The communication device according to claim 10, The determination information includes first information and second information, the first information includes the timer information, and the second information is different from the timer information, When the control unit determines to release the CPC configuration based on the second information, the control unit releases the CPC configuration even if the timer information indicates to maintain the CPC configuration.

14. The communication device according to claim 1, The decision information includes event information indicating a condition for releasing the CPC configuration, The control section maintains the CPC configuration until the condition is satisfied.

15. The communication device according to claim 1, The decision information includes event information indicating a condition for releasing the CPC configuration, When the condition is met, the control unit releases the CPC configuration.

16. The communication device according to claim 15, When the PS cell is changed after the condition is satisfied, the control unit releases the CPC configuration.

17. The communication device according to claim 14, The determination information includes first information and second information, the first information includes the event information, and the second information is different from the number of times information. When the control unit determines to release the CPC configuration based on the second information, the control unit releases the CPC configuration even if the event information indicates that the CPC configuration should be maintained.

18. The communication device according to claim 1, The control unit determines whether to release all CPC configurations configured for the communication device based on the determination information.

19. The communication device according to claim 1, The control unit determines whether to release the CPC configuration based on the determination information, wherein the CPC configuration is the CPC configuration for the SCG associated with the determination information in the RRC message among the SCGs configured for the communication device.

20. The communication device according to claim 1, The control unit determines whether to release the CPC configuration based on the determination information, wherein the CPC configuration is a CPC configuration associated with the determination information in the RRC message among CPC configurations configured for the communication device.

21. The communication device according to claim 1, The RRC message includes a list of SCG configurations, where the list is used to configure multiple SCG candidates including candidates for the PS cell.

22. A base station, a base station (200M) acting as the master node in a first network comprising a master node and a slave node, wherein the master node is associated with a master cell group MCG configured for a communication device (100), and the slave node is associated with a slave cell group SCG configured for the communication device, The base station includes a sending unit (211), which sends a radio resource control RRC message to the communication device, and the RRC message includes a conditional primary and secondary PS cell change CPC configuration and judgment information. The CPC configuration is a configuration of a PS cell that is a primary cell of the secondary cell group and is changed when an execution condition is met. The judgment information is used by the communication device to determine whether to release the CPC configuration.

23. A communication method, performed by a communication device (100), wherein the communication device communicates with a primary cell group and a secondary cell group, wherein the primary cell group is associated with a primary node, and the secondary cell group is associated with a secondary node, and the communication method comprises: a step of receiving a radio resource control RRC message, the RRC message including a conditional primary and secondary PS cell change CPC configuration and determination information, the CPC configuration is a configuration of a PS cell that is a primary cell of the secondary cell group and is changed when an execution condition is met, the determination information is used by the communication device to determine whether to release the CPC configuration; and The step of determining whether to release the CPC configuration based on the determination information.

24. A communication method, the communication method being performed by a base station (200M), the base station acting as the master node in a first network comprising a master node and a secondary node, the master node being associated with a master cell group MCG configured for a communication device (100), the secondary node being associated with a secondary cell group SCG configured for the communication device, The communication method includes the step of sending a radio resource control RRC message to the communication device, the RRC message including a conditional primary and secondary PS cell change CPC configuration and determination information, the CPC configuration is a configuration change of the PS cell as the primary cell of the secondary cell group when an execution condition is met, and the determination information is used by the communication device to determine whether to release the CPC configuration.

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