Terminal device, base station device, method, and integrated circuit

Abstract

A terminal device comprises: a reception unit that receives a message notifying that a second cell group is to be placed in a first state; and a processing unit that, on the basis of the message, causes cells other than a second cell that are included in the second cell group to transition to a deactivated state. The first state is a state in which the second cell is not in a deactivated state and the terminal device does not monitor a physical downlink control channel in a first cell. The second cell is a cell that at least supports a physical uplink control channel and collision-based random access.

Description

[Technical Field]

[0001] The present invention relates to a terminal device, a base station device, a method, and an integrated circuit. This application claims priority from Japanese Patent Application No. 2020-41468, filed on March 11, 2020, the contents of which are incorporated herein by reference. [Background technology]

[0002] A radio access method and radio network for cellular mobile communications (hereinafter referred to as "Long Term Evolution (LTE)" or "Evolved Universal Terrestrial Radio Access: EUTRA") and a core network (hereinafter referred to as "Evolved Packet Core: EPC") are being studied by the 3rd Generation Partnership Project (3GPP). EUTRA is also referred to as E-UTRA.

[0003] Furthermore, 3GPP is currently conducting technical studies and formulating standards for LTE-Advanced Pro, an extension of LTE, and NR (New Radio technology), a new radio access technology, as radio access methods and radio network technologies for fifth-generation cellular systems (Non-Patent Document 1). 5GC (5th Generation Core Network), a core network for fifth-generation cellular systems, is also being studied (Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP RP-170855, “Work Item on New Radio (NR) Access Technology” [Non-patent document 2] 3GPP TS 23.501 v15.3.0, “System Architecture for the 5G System; Stage 2” [Non-licensed document 3] 3GPP RP-182076, “WID on Multi-RAT Dual-Connectivity and Carrier Aggregation enhancements” [Non-licensed document 4] 3GPP TS 36.300, v15.3.0, "Evolved Universal Terestrial Radio Access (E-UTRA) and Evolved Universal Terestrial Radio Access Network (E-UTRAN); Overall description; Stage 2"

Non-licensed Document 5

Non-licensed Document 6

Non-licensed Document 7

Non-licensed literature 9

[0005] One NR technology is dual connectivity (also called multi-connectivity), which uses multiple cell groups to enable large-volume data communications between one or multiple base station devices and a terminal device. In this dual connectivity technology, in order to communicate in each cell group, the terminal device must monitor each cell group for messages addressed to it. The terminal device must constantly monitor multiple cell groups to ensure low-latency communications when large-volume data communications occur, which results in a problem of high power consumption. Therefore, studies have begun on a technology to monitor some cell groups less frequently or to stop monitoring them (cell group dormant technology) (Non-Patent Document 3).

[0006] In the case of cell group dormancy, currently, we are considering how to handle cells (SpCells) that are always in an activated state, but we also need to consider cells other than SpCells.

[0007] One aspect of the present invention has been made in consideration of the above-mentioned circumstances, and one of its objects is to provide a terminal device, a base station device, a method, and an integrated circuit that can efficiently perform communication control. [Means for solving the problem]

[0008] (1) In order to achieve the above object, one aspect of the present invention takes the following measures: That is, a first embodiment of the present invention is a terminal device that communicates using a first cell group including a first cell and a second cell group including a second cell, the terminal device comprising: a receiving unit that receives a message notifying that the second cell group is to be set to a first state; and a processing unit that transitions cells other than the second cell included in the second cell group to an inactive state based on the message, the first state being a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0009] (2) A second embodiment of the present invention is a base station device that communicates with a terminal device using a first cell group including a first cell and a second cell group including a second cell, and includes a transmitting unit that transmits a message notifying that the second cell group is in a first state, and a processing unit that generates the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0010] (3) A third embodiment of the present invention is a method applied to a terminal device that communicates using a first cell group including a first cell and a second cell group including a second cell, comprising the steps of receiving a message notifying that the second cell group will be in a first state, and transitioning cells other than the second cell included in the second cell group to an inactive state based on the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0011] (4) A fourth embodiment of the present invention is a method applied to a base station device that communicates with a terminal device using a first cell group including a first cell and a second cell group including a second cell, comprising the steps of: transmitting a message notifying that the second cell group is in a first state; and generating the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0012] (5) A fifth embodiment of the present invention is an integrated circuit implemented in a terminal device that communicates using a first cell group including a first cell and a second cell group including a second cell, and that causes the terminal device to perform the functions of receiving a message notifying that the second cell group is to be set to a first state and transitioning cells other than the second cell included in the second cell group to an inactive state based on the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0013] (6) A sixth embodiment of the present invention is an integrated circuit implemented in a base station device that communicates with a terminal device using a first cell group including a first cell and a second cell group including a second cell, and causes the base station device to perform a function of transmitting a message notifying that the second cell group is in a first state and a function of generating the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0014] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0015] According to one aspect of the present invention, a terminal device can realize efficient communication control processing. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram of a communication system according to each embodiment of the present invention. [Figure 2] 3A and 3B are protocol stack diagrams of UP and CP of a terminal device and a base station device in E-UTRA in each embodiment of the present invention. [Figure 3] A protocol stack diagram of the UP and CP of a terminal device and a base station device in NR in each embodiment of the present invention. [Figure 4] FIG. 10 is a diagram showing an example of a procedure flow for various settings in RRC 208 and / or RRC 308 according to each embodiment of the present invention. [Figure 5] FIG. 2 is a block diagram showing the configuration of a terminal device according to each embodiment of the present invention. [Figure 6] FIG. 2 is a block diagram showing the configuration of a base station device according to each embodiment of the present invention. [Figure 7] A figure showing an example of information elements for cell group configuration in NR in an embodiment of the present invention. [Figure 8] FIG. 2 is a diagram showing an example of information elements for cell group configuration in E-UTRA according to an embodiment of the present invention. [Figure 9] FIG. 3 is a diagram showing an example of processing relating to SCG sleep in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0018] LTE (and LTE-A Pro) and NR may be defined as different radio access technologies (RATs). NR and LTE connectable via Multi Radio Dual connectivity may be distinguished from conventional LTE. LTE using a 5GC core network may be distinguished from conventional LTE using an EPC core network. This embodiment may be applied to NR, LTE, and other RATs. In the following description, terms related to LTE and NR are used, but this embodiment may be applied to other technologies using other terms. In this embodiment, the term E-UTRA may be replaced with the term LTE, and the term LTE may be replaced with the term E-UTRA.

[0019] FIG. 1 is a schematic diagram of a communication system according to each embodiment of the present invention.

[0020] E-UTRA 100 is a radio access technology described in Non-Patent Document 4 and the like, and is composed of cell groups (CGs) each consisting of one or more frequency bands. eNB (E-UTRAN Node B) 102 is a base station device for E-UTRA 100. EPC (Evolved Packet Core) 104 is a core network described in Non-Patent Document 14 and the like, and was designed as a core network for E-UTRA 100. Interface 112 is an interface between eNB 102 and EPC 104, and includes a control plane (CP) through which control signals pass and a user plane (UP) through which user data passes.

[0021] NR106 is a radio access technology described in Non-Patent Document 5 and the like, and is composed of cell groups (CGs) consisting of one or more frequency bands. gNB (g Node B) 108 is a base station device for NR106. 5GC110 is a core network described in Non-Patent Document 2 and the like, and is designed as a core network for NR106, but may also be used as a core network for E-UTRA100 that has the function of connecting to 5GC110. Hereinafter, E-UTRA100 may include E-UTRA100 that has the function of connecting to 5GC110.

[0022] Interface 114 is an interface between eNB102 and 5GC110, interface 116 is an interface between gNB108 and 5GC110, interface 118 is an interface between gNB108 and EPC104, interface 120 is an interface between eNB102 and gNB108, and interface 124 is an interface between EPC104 and 5GC110. Interfaces 114, 116, 118, 120, 124, etc. may be interfaces that pass only CP, only UP, or both CP and UP. Furthermore, interfaces 114, 116, 118, 120, 124, etc. may not exist depending on the communication system provided by the communication carrier.

[0023] The UE 122 is a terminal device compatible with some or all of the E-UTRA 100 and the NR 106. As described in Non-Patent Document 4 and some or all of Non-Patent Document 5, when the UE 122 connects to the core network via some or all of the E-UTRA 100 and the NR 106, a logical path called a radio bearer (RB) is established between the UE 122 and some or all of the E-UTRA 100 and the NR 106. The radio bearer used for CP is called a signaling radio bearer (SRB), and the radio bearer used for UP is called a data radio bearer (DRB).

[0024] FIG. 2 is a diagram showing protocol stacks of UP and CP of a terminal device and a base station device in the E-UTRA radio access layer (radio access layer) in each embodiment of the present invention.

[0025] FIG. 2A is a diagram of a protocol stack of the UP used when the UE 122 communicates with the eNB 102 in the E-UTRA 100.

[0026] The PHY (Physical layer) 200 is a wireless physical layer that provides transmission services to an upper layer using a physical channel. The PHY 200 is connected to a higher layer, a Medium Access Control (MAC) layer 202 (described later), via a transport channel. Data moves between the MAC 202 and the PHY 200 via the transport channel. Data is transmitted and received between the PHYs of the UE 122 and the eNB 102 via the wireless physical channel.

[0027] The MAC 202 is a medium access control layer that maps various logical channels to various transport channels. The MAC 202 is connected to the higher-level RLC (Radio Link Control) layer 204 (described later) via a logical channel. Logical channels are broadly classified according to the type of information transmitted, into control channels that transmit control information and traffic channels that transmit user information. The MAC 202 may have functions such as controlling the PHY 200 to perform discontinuous transmission / reception (DRX / DTX), executing a random access procedure, reporting transmission power information, and performing HARQ control. The MAC 302 may also have a function to control the activation state of a cell set in the RRC layer (see Non-Patent Document 6).

[0028] The RLC 204 is a radio link control layer that segments data received from the higher-level PDCP (Packet Data Convergence Protocol Layer) 206 (described later) and adjusts the data size so that the lower layer can transmit the data appropriately.

[0029] The PDCP 206 is a packet data convergence protocol layer for efficiently transmitting user data such as IP packets over wireless sections. The PDCP 206 may have a header compression function for compressing unnecessary control information. The PDCP 206 may also have a data encryption function.

[0030] The data processed by the MAC 202, RLC 204, and PDCP 206 are called MAC PDUs (Protocol Data Units), RLC PDUs, and PDCP PDUs, respectively. Data passed from higher layers to the MAC 202, RLC 204, and PDCP 206, or data passed to higher layers, are called MAC SDUs (Service Data Units), RLC SDUs, and PDCP SDUs, respectively. Divided RLC SDUs are called RLC SDU segments.

[0031] FIG. 2B is a protocol stack diagram of a CP used when a UE 122 communicates with an eNB 102 and an MME (Mobility Management Entity) which is a logical node that provides functions such as authentication and mobility management in E-UTRA 100.

[0032] The CP protocol stack includes a PHY 200, a MAC 202, an RLC 204, a PDCP 206, a Radio Resource Control layer (RRC) 208, and a non-access stratum (NAS) 210. The RRC 208 is a radio link control layer that performs processes such as establishing, re-establishing, suspending, and resuming an RRC connection, resetting the RRC connection, for example, establishing, changing, and releasing radio bearers (RBs) and cell groups, controlling logical channels, transport channels, and physical channels, and also configuring handovers and measurements. RBs may be divided into signaling radio bearers (SRBs) and data radio bearers (DRBs). SRBs may be used as paths for transmitting RRC messages, which are control information. DRBs may be used as paths for transmitting user data. Each RB may be configured between the eNB 102 and the RRC 208 of the UE 122. Furthermore, a portion of the RB configured with the RLC 204 and a logical channel may be referred to as an RLC bearer. Furthermore, in contrast to the NAS layer that carries signals between the MME and the UE 122, some or all of the layers including the PHY 200, MAC 202, RLC 204, PDCP 206, and RRC 208 that carry signals and data between the UE 122 and the eNB 102 may be referred to as an AS (Access Stratum) layer.

[0033] The above-described classification of functions into MAC 202, RLC 204, PDCP 206, and RRC 208 is an example, and some or all of the functions may not be implemented. Also, some or all of the functions of each layer may be included in another layer.

[0034] The IP layer, and layers above the IP layer such as the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and application layer are upper layers (not shown) of the PDCP layer. The RRC layer and NAS (non-access strat) layer are also upper layers (not shown) of the PDCP layer. In other words, the PDCP layer is lower layers (lower layers) of the RRC layer, NAS layer, IP layer, and layers above the IP layer such as the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and application layer.

[0035] FIG. 3 is a diagram of the protocol stack of the UP and CP of the terminal device and base station device in the NR radio access layer in each embodiment of the present invention.

[0036] Figure 3(A) is a protocol stack diagram of the UP used when UE 122 communicates with gNB 108 in NR 106.

[0037] The PHY (Physical layer) 300 is a radio physical layer of NR and may provide transmission services to higher layers using a physical channel. The PHY 300 may be connected to a higher-level MAC (Medium Access Control layer) 302 (described later) via a transport channel. Data may be transferred between the MAC 302 and the PHY 300 via the transport channel. Data may be transmitted and received between the PHYs of the UE 122 and the gNB 108 via a radio physical channel.

[0038] Here, the physical channels will be described.

[0039] The following physical channels may be used in wireless communication between a terminal device and a base station device.

[0040] PBCH (Physical Broadcast CHannel) PDCCH (Physical Downlink Control CHannel) PDSCH (Physical Downlink Shared CHannel) PUCCH (Physical Uplink Control CHannel) PUSCH (Physical Uplink Shared CHannel) PRACH (Physical Random Access CHannel)

[0041] The PBCH is used to broadcast system information required by terminal devices.

[0042] In addition, in NR, the PBCH may be used to broadcast a time index (SSB-Index) within the period of a synchronization signal block (also referred to as an SS / PBCH block).

[0043] The PDCCH is used to transmit (or carry) downlink control information (DCI) in downlink wireless communication (wireless communication from a base station device to a terminal device). Here, one or more DCIs (which may be referred to as DCI formats) are defined for transmitting the downlink control information. That is, a field for the downlink control information is defined as DCI and mapped to information bits. The PDCCH is transmitted in PDCCH candidates. The terminal device monitors a set of PDCCH candidates in the serving cell. Monitoring means attempting to decode the PDCCH according to a certain DCI format. A certain DCI format may be used for scheduling the PUSCH in the serving cell. The PUSCH may be used for transmitting user data, RRC messages, etc.

[0044] The PUCCH may be used to transmit uplink control information (UCI) in uplink wireless communication (wireless communication from a terminal device to a base station device). Here, the uplink control information may include channel state information (CSI) used to indicate the state of a downlink channel. The uplink control information may also include a scheduling request (SR) used to request UL-SCH resources. The uplink control information may also include a hybrid automatic repeat request ACKnowledgement (HARQ-ACK).

[0045] The PDSCH may be used to transmit downlink data (DL-SCH: Downlink Shared CHannel) from the MAC layer, and in the case of downlink, it is also used to transmit system information (SI: System Information) and random access response (RAR: Random Access Response).

[0046] The PUSCH may be used to transmit uplink data from the MAC layer (UL-SCH: Uplink Shared CHannel) or HARQ-ACK and / or CSI together with uplink data. The PUSCH may also be used to transmit only CSI, or only HARQ-ACK and CSI. That is, the PUSCH may be used to transmit only UCI. The PDSCH or PUSCH may also be used to transmit RRC signaling (also referred to as an RRC message) and MAC control elements (MAC CEs). Here, in the PDSCH, the RRC signaling transmitted from the base station apparatus may be signaling common to multiple terminal apparatuses within a cell. The RRC signaling transmitted from the base station apparatus may also be signaling dedicated to a certain terminal apparatus (also referred to as dedicated signaling). That is, terminal apparatus-specific (UE-specific) information may be transmitted using signaling dedicated to a certain terminal apparatus. Furthermore, the PUSCH may be used to transmit UE capabilities in the uplink.

[0047] The PRACH may be used to transmit a random access preamble and may be used for initial connection establishment procedures, handover procedures, connection re-establishment procedures, synchronization (timing adjustment) for uplink transmissions, and to indicate requests for PUSCH (UL-SCH) resources.

[0048] The MAC 302 is a medium access control layer that maps various logical channels to various transport channels. The MAC 302 may be connected to a higher-level RLC (Radio Link Control) layer 304 (described later) via a logical channel. Logical channels are broadly classified according to the type of information transmitted, and may be divided into control channels that transmit control information and traffic channels that transmit user information. The MAC 302 may have functions such as controlling the PHY 300 to perform discontinuous transmission / reception (DRX / DTX), executing a random access procedure, reporting transmission power information, and performing HARQ control. The MAC 302 may also have a function to control the activation state of a cell set in the RRC layer (see Non-Patent Document 7).

[0049] The RLC 304 is a radio link control layer that segments data received from the higher-level PDCP (Packet Data Convergence Protocol Layer) 306 (described later) and adjusts the data size so that the lower layers can transmit the data appropriately.

[0050] PDCP 306 is a packet data convergence protocol layer that efficiently transmits user data such as IP packets over wireless interfaces. PDCP 306 may have a header compression function that compresses unnecessary control information. PDCP 306 may also have functions for encrypting data and protecting data integrity.

[0051] SDAP (Service Data Adaptation Protocol) 310 is a service data adaptation protocol layer that has the function of mapping the downlink QoS flow sent from 5GC110 to a terminal device via a base station device to a DRB, and mapping the uplink QoS flow sent from the terminal device to 5GC110 via a base station device to a DRB, and storing mapping rule information.

[0052] The data processed in MAC 302, RLC 304, PDCP 306, and SDAP 310 are called MAC PDU (Protocol Data Unit), RLC PDU, PDCP PDU, and SDAP PDU, respectively. Data passed from or to upper layers to MAC 302, RLC 304, PDCP 306, and SDAP 310 are called MAC SDU (Service Data Unit), RLC SDU, PDCP SDU, and SDAP SDU, respectively. Segmented RLC SDUs are called RLC SDU segments.

[0053] Figure 3(B) is a protocol stack diagram of the CP used when UE 122 communicates with gNB 108 and AMF (Access and Mobility Management function), a logical node that provides functions such as authentication and mobility management, in NR 106.

[0054] The CP protocol stack includes a PHY 300, a MAC 302, an RLC 304, a PDCP 306, a Radio Resource Control layer (RRC) 308, and a non-access stratum (NAS) 312. The RRC 308 is a radio link control layer that performs processes such as establishing, re-establishing, suspending, and resuming an RRC connection, resetting the RRC connection, for example, establishing, changing, and releasing radio bearers (RBs) and cell groups, controlling logical channels, transport channels, and physical channels, and configuring handovers and measurements. RBs may be divided into signaling radio bearers (SRBs) and data radio bearers (DRBs). The SRBs may be used as paths for transmitting RRC messages, which are control information. The DRBs may be used as paths for transmitting user data. RBs may be configured between the gNB 108 and the RRC 308 of the UE 122. Furthermore, a portion of the RBs configured with the RLC 304 and logical channels may be referred to as an RLC bearer. Furthermore, in contrast to the NAS layer that carries signals between the AMF and the UE 122, some or all of the layers including the PHY 300, MAC 302, RLC 304, PDCP 306, RRC 308, and SDAP 310 that carry signals and data between the UE 122 and the gNB 108 may be referred to as an AS (Access Stratum) layer.

[0055] The functional classification of MAC 302, RLC 304, PDCP 306, SDAP 310, and RRC 308 described above is an example, and some or all of the functions may not be implemented. Furthermore, some or all of the functions of each layer may be included in another layer.

[0056] Note that the layer above the AS layer (not shown) may be referred to as the PDU layer, as described in Non-Patent Document 2. The PDU layer may include any or all of the IP layer and the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and other layers above the IP layer. The application layer may be a layer above the PDU layer or may be included in the PDU layer. Note that the PDU layer may be a layer above the user plane of the AS layer. The RRC layer and NAS (non-access strat) layer may also be upper layers of any or all of the SDAP layer and PDCP layer (not shown). In other words, any or all of the SDAP layer and PDCP layer may be lower layers of any or all of the RRC layer, NAS layer, IP layer, and the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and application layer above the IP layer.

[0057] The physical layer, MAC layer, RLC layer, PDCP layer, and SDAP layer of the terminal device may be established, configured, and / or controlled by the RRC layer of the terminal device. The RRC layer of the terminal device may establish and / or configure the physical layer, MAC layer, RLC layer, PDCP layer, and SDAP layer in accordance with an RRC message transmitted from the RRC layer of the base station device. The MAC layer, RLC layer, PDCP layer, and SDAP layer may be referred to as the MAC sublayer, RLC sublayer, PDCP sublayer, and SDAP sublayer, respectively.

[0058] Note that each layer or function of each layer belonging to the AS layer configured in any or all of the terminal device and base station device may be referred to as an entity. That is, the physical layer (PHY layer), MAC layer, RLC layer, PDCP layer, SDAP layer, and RRC layer, or the functions of each layer, which are established, configured, and / or controlled in any or all of the terminal device and base station device, may be referred to as a physical entity (PHY entity), MAC entity, RLC entity, PDCP entity, SDAP entity, and RRC entity, respectively. Also, each layer may include one or more entities. Also, the PDCP entity and the RLC entity may establish, configure, and / or control any or all of the PDCP entity, the RLC entity, for each radio bearer. Also, the MAC entity may establish, configure, and / or control any or all of the PDCP entity, the RLC entity, for each cell group. Also, the SDAP entity may establish, configure, and / or control any or all of the PDCP entity, the RLC entity, for each radio bearer.

[0059] In each embodiment of the present invention, in order to distinguish between E-UTRA protocols and NR protocols, MAC 202, RLC 204, PDCP 206, and RRC 208 may be referred to as E-UTRA MAC or LTE MAC, E-UTRA RLC or LTE RLC, E-UTRA PDCP or LTE PDCP, and E-UTRA RRC or LTE RRC, respectively. MAC 302, RLC 304, PDCP 306, and RRC 308 may be referred to as NR MAC, NR RLC, NR RLC, and NR RRC, respectively. Alternatively, they may be written with spaces, such as E-UTRA PDCP or LTE PDCP, or NR PDCP.

[0060] 1, the eNB 102, the gNB 108, the EPC 104, and the 5GC 110 may be connected via an interface 112, an interface 116, an interface 118, an interface 120, and an interface 114. Therefore, in order to support various communication systems, the RRC 208 in FIG. 2 may be replaced with the RRC 308 in FIG. 3. The PDCP 206 in FIG. 2 may be replaced with the PDCP 306 in FIG. 3. The RRC 308 in FIG. 3 may include the functions of the RRC 208 in FIG. 2. The PDCP 306 in FIG. 3 may be the PDCP 206 in FIG. 2. In E-UTRA 100, even when the UE 122 communicates with the eNB 102, NR PDCP may be used as the PDCP.

[0061] Next, the state transitions of the UE 122 in LTE and NR will be described. A UE 122 connected to EPC or 5GC may be in the RRC_CONNECTED state when an RRC connection has been established. The state in which an RRC connection is established may include a state in which the UE 122 holds some or all of the UE context described below. The state in which an RRC connection is established may also include a state in which the UE 122 can transmit and / or receive unicast data. The UE 122 may be in the RRC_INACTIVE state when the RRC connection is inactive (if the UE 122 is connected to 5GC). If neither of these cases is true, the UE 122 may be in the RRC_IDLE state.

[0062] Note that the UE 122 connected to the EPC does not have an RRC_INACTIVE state, but the suspension of the RRC connection may be initiated by the E-UTRAN. In this case, when the RRC connection is suspended, the UE 122 transitions to the RRC_IDLE state while retaining the UE AS context and an identifier (resumeIdentity) used for resumption. When the UE 122 retains the UE AS context, the E-UTRAN has permitted the resumption of the RRC connection, and the UE 122 needs to transition from the RRC_IDLE state to the RRC_CONNECTED state, the resumption of the suspended RRC connection may be initiated by a higher layer (e.g., the NAS layer).

[0063] That is, the definition of dormancy may be different for UE 122 connected to EPC and UE 122 connected to 5GC. Also, all or part of the procedure for UE 122 to return from dormancy may be different when UE 122 is connected to EPC (when dormant in RRC_IDLE state) and when UE 122 is connected to 5GC (when dormant in RRC_INACTIVE state).

[0064] The RRC_CONNECTED state, RRC_INACTIVE state, and RRC_IDLE state may be referred to as the connected state (connected mode), the inactive state (inactive mode), and the idle state (idle mode), respectively, or as the RRC connected state (RRC connected mode), the RRC inactive state (RRC inactive mode), and the RRC idle mode (RRC idle mode).

[0065] The UE AS context held by the UE 122 may be information including all or some of the following: a current RRC configuration, a current security context, a PDCP state including a ROHC (Robust Header Compression) state, a C-RNTI (Cell Radio Network Temporary Identifier) used in the source PCell, a cell identifier (cellIdentity), and a physical cell identifier of the source PCell. Note that the UE AS context held by one or all of the eNB 102 and the gNB 108 may include the same information as the UE AS context held by the UE 122, or may include information different from the information included in the UE AS context held by the UE 122.

[0066] Fig. 4 is a diagram showing an example of a procedure flow for various settings in the RRC 208 and / or the RRC 308 according to each embodiment of the present invention. Fig. 4 shows an example of a flow when an RRC message is sent from a base station device (eNB 102 and / or gNB 108) to a terminal device (UE 122).

[0067] In FIG. 4, the base station device creates an RRC message (step S400). The base station device may create an RRC message when it distributes system information (SI) or paging information, or when it determines that a process needs to be performed by a specific terminal device, such as security settings, reconfiguration of an RRC connection (radio bearer processing (establishment, change, release, etc.), cell group processing (establishment, addition, change, release, etc.), measurement setting, handover setting, etc.), or release of the RRC connection state. The RRC message includes information (parameters) for various information notifications and settings. In RRC specifications (Non-Patent Document 8, Non-Patent Document 9), these parameters are called fields and / or information elements, and are described using a description format called ASN.1 (Abstract Syntax Notation One).

[0068] The RRC message may be created for other purposes, for example, the RRC message may be used for settings related to Dual Connectivity (DC) or Multi-Radio Dual Connectivity (MR-DC).

[0069] 4, the base station device then transmits the created RRC message to the terminal device (step S402). Next, the terminal device performs processing such as setting according to the received RRC message if necessary (step S404).

[0070] Dual Connectivity (DC) may be a technology for performing data communication using radio resources of both cell groups configured by two base station devices (nodes), i.e., a master cell group (MCG) configured by a master node (MN) and a secondary cell group (SCG) configured by a secondary node (SN). The master node and the secondary node may be the same node (same base station device). MR-DC may be a technology for grouping cells of both E-UTRA and NR radio access technologies (RATs) into cell groups for each RAT, assigning them to UEs, and performing data communication using radio resources of both the MCG and the SCG. In MR-DC, the master node may be a base station having main RRC functions related to MR-DC, such as adding a secondary node, establishing, changing, and releasing RBs, adding, changing, and releasing MCGs, and handover functions. The secondary node may be a base station having some RRC functions, such as changing and releasing SCGs.

[0071] In MR-DC, RRC of the RAT on the master node side may be used to configure both the MCG and the SCG. For example, in EN-DC (E-UTRA-NR Dual Connectivity), which is MR-DC when the core network is EPC104 and the master node is eNB102 (also referred to as enhanced eNB102), and in NGEN-DC (NG-RAN E-UTRA-NR Dual Connectivity), which is MR-DC when the core network is 5GC110 and the master node is eNB102, an E-UTRA RRC message may be transmitted and received between the eNB102 and the UE122. In this case, the RRC message may include not only LTE (E-UTRA) configuration information but also NR configuration information. Furthermore, the RRC message transmitted from the eNB102 to the UE122 may be transmitted from the eNB102 to the UE122 via the gNB108. In addition, this RRC message configuration may be used for non-MR-DC E-UTRA / 5GC in which the eNB 102 (enhanced eNB) uses 5GC as a core network.

[0072] Conversely, in MR-DC, in NE-DC (NR-E-UTRA Dual Connectivity), which is MR-DC when the core network is 5GC 110 and the master node is gNB 108, NR RRC messages may be transmitted and received between gNB 108 and UE 122. In this case, the RRC message may include not only NR configuration information but also LTE (E-UTRA) configuration information. Furthermore, the RRC message transmitted from gNB 108 to UE 122 may be transmitted from gNB 108 to UE 122 via eNB 102.

[0073] In addition, regardless of whether MR-DC is used, the RRC message for E-UTRA transmitted from eNB102 to UE122 may include an RRC message for NR, or the RRC message for NR transmitted from gNB108 to UE122 may include an RRC message for E-UTRA.

[0074] FIG. 7 is an example of an ASN.1 description representing some or all of the fields and information elements related to cell group establishment included in the message related to RRC connection reestablishment in NR in FIG. 4. FIG. 8 is an example of an ASN.1 description representing some or all of the fields and information elements related to cell group establishment included in the message related to RRC connection reestablishment in E-UTRA in FIG. 4. In the ASN.1 examples in the embodiments of the present invention, including but not limited to FIGS. 7 and 8, the symbols "omitted" and "omitted" are not part of the ASN.1 notation and indicate the omission of other information. Note that information elements may be omitted even in places without the symbols "omitted" or "omitted." Note that the ASN.1 examples in the embodiments of the present invention do not strictly follow the ASN.1 notation method but represent example parameters of a message related to RRC connection reestablishment in the embodiments of the present invention, and other names and notations may be used. ... in order to avoid complication of explanation, only examples of main information closely related to one embodiment of the present invention are shown. Note that parameters described in ASN.1 may be referred to as information elements without being distinguished as fields, information elements, etc. Also, in the embodiments of the present invention, parameters such as fields and information elements described in ASN.1 that are included in an RRC message may be referred to as information. Note that the message related to the reconfiguration of the RRC connection may be an RRC reconfiguration message in NR or an RRC connection reconfiguration message in E-UTRA.

[0075] In Fig. 7, radioBearerConfig included in the RRCReconfiguration message may include radio bearer settings. masterCellGroup may include settings related to the MCG when the MCG is NR. secondaryCellGroup may include settings related to the SCG when notified to the terminal device from a cell of the SCG. mrdc-SecondaryCellGroupConfig may include settings related to the SCG when notified to the terminal device from a cell of the MCG.

[0076] The above masterCellGroup, secondaryCellGroup, and / or mrdc-SecondaryCellGroupConfig may include a CellGroupConfig information element as a value.

[0077] The CellGroupConfig information element may include settings related to a cell group. The cellGroupId included in the CellGroupConfig information element may include information on an identifier for identifying a cell group. The mac-CellGroupConfig may include settings related to the MAC layer of the cell group. The spCellConfig may include settings related to the SpCell. The sCellToAddModList may include settings related to adding or changing SCells belonging to the cell group. The sCellToReleaseList may include information related to removing SCells belonging to the cell group.

[0078] In FIG. 8, sCellToReleaseList-r10 included in the RRCConnectionReconfiguration message may include information regarding the removal of an SCell belonging to an MCG. sCellToAddModList-r10 may include configuration regarding the addition or modification of an SCell belonging to an MCG. scg-Configuration-r12 may include configuration regarding the SCG. scg-ConfigPartSCG-r12 included in scg-Configuration-r12 may include configuration regarding an SpCell of an SCG (e.g., pSCellToAddMod-r12), configuration regarding the addition or modification of an SCell belonging to a cell group (e.g., sCellToAddModListSCG-r12), and / or information regarding the removal of an SCell belonging to a cell group (e.g., sCellToReleaseListSCG-r12). Furthermore, information indicating the initial state of an SCell may be included in the configuration regarding the addition or modification of an SCell at the time of handover and / or the configuration regarding the addition or modification of an SCell when adding an SCell. For example, information indicating either an activated state or a dormant state may be included in the RRC message. If this information is included, the initial state of the SCell may be set to an activated state or a dormant state based on this information. If this information is not included, the initial state of the SCell may be set to a deactivated state.

[0079] The above fields and information elements are not necessarily limited to the above uses.

[0080] A terminal device that receives an RRC message including the above information from a base station device configures an SpCell (PCell) of the MCG, an SCell of the MCG, an SpCell (PSCell) of the SCG, and / or an SCell of the SCG based on the information.

[0081] The terminal device may perform radio link monitoring using a certain type of reference signal (e.g., a cell-specific reference signal (CRS)) in a serving cell (e.g., a PCell and / or a PSCell). The terminal device may also receive a configuration (radio link monitoring configuration: RadioLinkMonitoringConfig) indicating which reference signal is to be used for radio link monitoring in a serving cell (e.g., a PCell and / or a PSCell) from a base station device, and perform radio link monitoring using one or more configured reference signals (referred to here as RLM-RS). The terminal device may also perform radio link monitoring using other signals. When a condition for being synchronized in the serving cell (e.g., a PCell and / or a PSCell) is met, the physical layer processing unit of the terminal device may notify a higher layer that it is in synchronization.

[0082] The radio link monitoring configuration may include information indicating a monitoring purpose and identifier information indicating a reference signal. For example, the monitoring purpose may include a purpose of monitoring a radio link failure, a purpose of monitoring a beam failure, or both purposes. Furthermore, for example, the identifier information indicating the reference signal may include information indicating an identifier (SSB-Index) of a synchronization signal block (SSB) of a cell. That is, the reference signal may include a synchronization signal. Furthermore, for example, the identifier information indicating the reference signal may include information indicating an identifier linked to a channel state information reference signal (CSI-RS) configured in the terminal device.

[0083] In an SpCell (a PCell in an MCG and a PSCell in an SCG), an RRC layer processing unit of a terminal device may start or restart a timer (T310) for each SpCell when it receives an out-of-sync notification from the physical layer processing unit for that SpCell a predetermined number of times (N310 times) consecutively. Furthermore, an RRC layer processing unit of a terminal device may stop a timer (T310) for that SpCell when it receives an in-sync notification for that SpCell a predetermined number of times (N311 times) consecutively. When the timer (T310) for each SpCell expires, if the SpCell is a PCell, the RRC layer processing unit of the terminal device may transition to an idle state or perform an RRC connection re-establishment procedure. Furthermore, if the SpCell is a PSCell, it may execute an SCG failure information procedure to notify the network of an SCG failure.

[0084] The above description is an example in which discontinuous reception (DRX) is not configured in the terminal device. When DRX is configured in the terminal device, the RRC layer processing unit of the terminal device may configure the physical layer processing unit so that the period for measuring radio link quality and the interval for reporting to higher layers take values different from those when DRX is not configured. Note that even when DRX is configured, when the timer is running, the period for measuring radio link quality to estimate synchronization and the interval for reporting to higher layers may take values when DRX is not configured.

[0085] Furthermore, the RLM-RS may be undefined if it is not explicitly or implicitly configured by the network, i.e., the terminal device does not need to monitor the radio link if the RLM-RS is not configured by the network (e.g., a base station device).

[0086] In addition, radio link monitoring using CRS may be performed in a EUTRA cell, and radio link monitoring using RLM-RS may be performed in an NR cell, but this is not limited to this.

[0087] Cell activation and deactivation will now be described. In a terminal device communicating via dual connectivity, a master cell group (MCG) and a secondary cell group (SCG) are configured by the above-mentioned message related to reconfiguration of the RRC connection. Each cell group may be composed of a special cell (SpCell) and zero or more other cells (secondary cells: SCell). The SpCell of the MCG is also referred to as a PCell. The SpCell of the SCG is also referred to as a PSCell. Cell deactivation does not apply to the SpCell, but may apply to the SCell.

[0088] Furthermore, cell deactivation may not be applied to PCells but may be applied to PSCells. In this case, cell deactivation may be performed differently for SpCells and SCells.

[0089] As shown in Non-Patent Document 6 and Non-Patent Document 7, cell activation and deactivation may be processed by a MAC entity that exists for each cell group. An SCell configured in a terminal device may be activated and / or deactivated by the following (A) and / or (B): (A) Receipt of MAC CE indicating SCell activation / deactivation (B) Timer (sCellDeactivationTimer) set for each SCell for which PUCCH is not configured

[0090] Specifically, the terminal device may perform the following process (AD) for each SCell configured in the cell group via the MAC entity.

[0091] (Processing AD) If a MAC CE for activating the SCell is received, process (AD-1) is performed. Otherwise, if a MAC CE for deactivating the SCell is received or the timer (sCellDeactivationTimer) for the active SCell expires, process (AD-2) is performed. If an uplink grant or downlink allocation is notified by the PDCCH of the active SCell, or if an uplink grant or downlink allocation for the active SCell is notified by the PDCCH of a serving cell, or if a MAC PDU is transmitted in the configured uplink grant or if a MAC PDU is received in the configured downlink allocation, the timer (sCellDeactivationTimer) associated with the SCell is restarted. If the SCell enters the inactive state, process (AD-3) is performed.

[0092] (Process AD-1)

[0093] The SCell is put into an active state, and normal SCell operations including some or all of the following (A) to (E) are applied (implemented). (A) Transmission of Sounding Reference Signal (SRS) in this SCell (B) Reporting of Channel State Information (CSI) for this SCell (C) Monitoring PDCCH in this SCell (D) Monitoring of PDCCH for this SCell (when scheduling for this SCell is performed in another serving cell) (E) If PUCCH is configured, PUCCH transmission on this SCell

[0094] Also, if the SCell was in an inactive state before receiving this activating MAC CE in NR, some or all of the following (A) to (B) are performed. (A) Activate the BWP indicated by the downlink BWP identifier (firstActiveDownlinkBWP-Id) configured in the RRC message. (B) Activate the BWP indicated by the uplink BWP identifier (firstActiveUplinkBWP-Id) configured in the RRC message.

[0095] It also starts, or restarts (if already started), the timer (sCellDeactivationTimer) associated with this SCell.

[0096] (Process AD-2)

[0097] This SCell is deactivated.

[0098] Also, the timer (sCellDeactivationTimer) associated with this SCell is stopped.

[0099] Deactivate all activated BWPs associated with this SCell.

[0100] The HARQ buffer associated with this SCell is flushed.

[0101] (Process AD-3) Implement some or all of the following (A) to (D). (A) Do not transmit SRS on this SCell. (B) Do not report CSI for this SCell. (C) Do not transmit PUCCH, UL-SCH, and / or RACH on this SCell. (D) Do not monitor the PDCCH of this SCell and / or the PDCCH for this SCell.

[0102] As described above, the MAC entity performs the process (AD) to activate and deactivate the SCell.

[0103] Furthermore, as described above, when an SCell is added, the initial state of the SCell may be set by an RRC message.

[0104] Here, the timer (sCellDeactivationTimer) will be described. For an SCell for which a PUCCH is not configured, the value of the timer (sCellDeactivationTimer) (information regarding the time at which the timer is considered to have expired) may be notified by an RRC message. For example, if information indicating 40 ms as the value of the timer (sCellDeactivationTimer) is notified by an RRC message, the timer is considered to have expired when the notified time (here, 40 ms) has elapsed without the timer being stopped after the timer is started or restarted in the above process (AD).

[0105] Here, the band portion (BWP) will be explained.

[0106] A BWP may be a part or all of the band of the serving cell. A BWP may also be referred to as a carrier BWP. One or more BWPs may be configured in a terminal device. A BWP may be configured by information included in broadcast information associated with a synchronization signal detected in an initial cell search. A BWP may also be a frequency bandwidth associated with a frequency at which an initial cell search is performed. A BWP may also be configured by RRC signaling (e.g., dedicated RRC signaling). A downlink BWP (DL BWP) and an uplink BWP (UL BWP) may also be configured separately. One or more uplink BWPs may also be associated with one or more downlink BWPs. Furthermore, the correspondence between the uplink BWP and the downlink BWP may be a predetermined correspondence, or may be correspondence based on RRC signaling (e.g., Dedicated RRC signaling), or may be correspondence based on physical layer signaling (e.g., Downlink Control Information (DCI) notified on a Downlink Control Channel), or may be a combination thereof.

[0107] A BWP may be configured by a group of consecutive physical resource blocks (PRBs). Furthermore, parameters of the BWP (one or more BWPs) of each component carrier may be configured for a terminal device in a connected state. The BWP parameters for each component carrier may include some or all of the following: (A) type of cyclic prefix, (B) subcarrier spacing, (C) frequency location of the BWP (e.g., start location or center frequency location on the lower frequency side of the BWP) (for example, ARFCN may be used for the frequency location, or an offset from a specific subcarrier of the serving cell may be used. The offset may be in units of subcarriers or resource blocks. Both the ARFCN and the offset may be configured.), (D) bandwidth of the BWP (e.g., the number of PRBs), (E) resource configuration information for the control signal, and (F) center frequency location of the SS block (for example, ARFCN may be used for the frequency location, or an offset from a specific subcarrier of the serving cell may be used. The offset may be in units of subcarriers or resource blocks. Both the ARFCN and the offset may be configured.) Furthermore, the resource configuration information for the control signal may be included in the configuration of the BWP for at least some or all of the PCell and / or PSCell.

[0108] A terminal device may transmit and receive in an active BWP among one or more configured BWPs. Also, a terminal device may be configured such that at any given time, at most one uplink BWP and at most one downlink BWP are active among one or more BWPs configured for one serving cell.

[0109] Next, we will explain SCG dormancy.

[0110] In LTE and / or NR, the state in which the SCG is dormant may be included in the RRC_CONNECTED state.

[0111] In LTE and / or NR, a state in which an SCG is dormant may be a state in which a terminal device performs some or all of the following (A) to (E) in the SpCell (PSCell) of that SCG. (A) Do not send SRS with this SpCell. (B) Do not report CSI for this SpCell. (C) Do not transmit PUCCH, UL-SCH, and / or RACH in this SpCell. (D) Do not monitor the PDCCH of this SpCell and / or the PDCCH for this SpCell. (E) This SpCell performs discontinuous reception (DRX).

[0112] In LTE and / or NR, a terminal device may determine and / or execute SCG dormancy based on some or all of the following (A) to (H): The messages and control elements (A) to (F) below may be notified to the terminal device from a cell group other than the SCG. (A) Receipt of an RRC message instructing the SCG to sleep (B) Receipt of a MAC control element instructing the SCG to sleep. (C) Receipt of an RRC message instructing the SpCell to sleep (D) Receipt of a MAC control element instructing the SpCell to sleep (E) Receiving other RRC messages (F) Receiving other MAC Control Elements (G)SCG sleep timer expiration (H) Expiration of the PSCell sleep timer

[0113] In LTE and / or NR, a terminal device may determine and / or execute a resume from a dormant state of an SCG based on some or all of the following (A) to (H): The messages and control elements (A) to (F) below may be notified to the terminal device from a cell group other than the SCG. (A) Receipt of an RRC message instructing the SCG to return from sleep mode (B) Receipt of a MAC Control Element instructing the SCG to wake up from sleep. (C) Receipt of an RRC message instructing the SpCell to return from sleep mode (D) Receipt of a MAC Control Element instructing the SpCell to return from sleep mode (E) Receiving other RRC messages (F) Receiving other MAC Control Elements (G) Timer for SCG dormancy (H) PSCell sleep timer

[0114] A terminal device that puts an SCG to sleep may execute some or all of the following processes (A) to (F) in the SCG. (A) All SCells are in an inactive state. (B) All timers (sCellDeactivationTimer) associated with the active SCell are considered to have expired. (C) All timers (sCellDeactivationTimer) associated with the dormant SCell are considered to have expired. (D) Do not start or restart the timer (sCellDeactivationTimer) associated with any SCell. (E) Ignore the MAC CE that activates the SCell. For example, in the process (AD), if a MAC CE that activates the SCell is received and an SCG dormancy command has not been issued (or the SCG is not in the dormant state), perform process (AD-1). (F) Execute the process (AD-2) For example, when an instruction to put the SCG to sleep is issued (or the SCG enters a sleep state) in the process (AD), the process (AD-2) is executed.

[0115] A terminal device that causes an SCG to return from a sleep state may perform some or all of the following processes (A) to (C) in the SCG. (A) To activate all SCells, process (AD-1) is executed. (B) All SCells remain in the inactive state. However, since they are not in the dormant state, for example, if a MAC CE to activate an SCell is received in the process (AD), the SCG has not been instructed to be dormant (or the SCG is not in the dormant state), so the process (AD-1) may be performed. (C) When the SCG resumes from sleep mode based on an RRC message, if this RRC message includes parameters related to random access to some or all SCells, a random access procedure is initiated on the target SCell based on the notified parameters.

[0116] Fig. 9 is a diagram showing an example of an embodiment. In Fig. 9, UE 122 receives a message (RRC message) from eNB 102 or gNB 108 notifying that the SCG will be put into a dormant state (first state) (step S902). Based on the notification, UE 122 controls cells (i.e., SCells) other than the SpCell (second cell) of the SCG to be put into an inactive state.

[0117] The above operation enables an efficient state change in the process of putting an SCG to sleep without separately transmitting a MAC CE for changing the state of the SCell of the SCG to an inactive state. Furthermore, when SCG sleep is executed based on an RRC message, the initial state is conventionally set in the RRC layer and the state change is performed in the MAC layer, but the above operation makes it possible to efficiently change the SCG state while avoiding a mismatch between instructions from the RRC layer and instructions from the MAC layer.

[0118] Fig. 5 is a block diagram showing the configuration of a terminal device (UE 122) in each embodiment of the present invention. To avoid complicating the explanation, Fig. 5 shows only the main components closely related to one embodiment of the present invention.

[0119] 5 includes a receiver 500 that receives an RRC message or the like from a base station device, a processor 502 that performs processing according to some or all of the setting information of various information elements (IEs), various fields, various conditions, and the like included in the received message, and a transmitter 504 that transmits the RRC message or the like to the base station device. The base station device may be the eNB 102 or the gNB 108. The processor 502 may include some or all of the functions of various layers (e.g., the physical layer, the MAC layer, the RLC layer, the PDCP layer, the RRC layer, and the NAS layer). That is, the processor 502 may include some or all of the physical layer processing section, the MAC layer processing section, the RLC layer processing section, the PDCP layer processing section, the RRC layer processing section, and the NAS layer processing section.

[0120] Fig. 6 is a block diagram showing the configuration of a base station device in each embodiment of the present invention. To avoid complicating the explanation, Fig. 6 shows only main components closely related to the present invention. The base station device may be an eNB 102 or a gNB 108.

[0121] 6 includes a transmitter 600 that transmits an RRC message or the like to the UE 122, a processor 602 that creates an RRC message including some or all of the setting information of various information elements (IEs), various fields, and various conditions, and transmits the RRC message to the UE 122, thereby causing the processor 502 of the UE 122 to perform processing, and a receiver 604 that receives the RRC message or the like from the UE 122. The processor 602 may include some or all of the functions of various layers (e.g., the physical layer, the MAC layer, the RLC layer, the PDCP layer, the RRC layer, and the NAS layer). That is, the processor 602 may include some or all of the functions of the physical layer processor, the MAC layer processor, the RLC layer processor, the PDCP layer processor, the RRC layer processor, and the NAS layer processor.

[0122] In addition, in each of the process examples or process flow examples described above, some or all of the steps may not be executed. In addition, in each of the process examples or process flow examples described above, the order of the steps may be different. In each of the process examples or process flow examples described above, some or all of the processing within each step may not be executed. In addition, in each of the process examples or process flow examples described above, the order of the processing within each step may be different.

[0123] Various aspects of the terminal device according to the embodiment of the present invention will be described below.

[0124] (1) A first embodiment of the present invention is a terminal device that communicates using a first cell group including a first cell and a second cell group including a second cell, and includes a receiving unit that receives a message notifying that the second cell group is to be in a first state, and a processing unit that transitions cells other than the second cell included in the second cell group to an inactive state based on the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0125] (2) A second embodiment of the present invention is a base station device that communicates with a terminal device using a first cell group including a first cell and a second cell group including a second cell, and includes a transmitting unit that transmits a message notifying that the second cell group is in a first state, and a processing unit that generates the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0126] (3) A third embodiment of the present invention is a method applied to a terminal device that communicates using a first cell group including a first cell and a second cell group including a second cell, comprising the steps of receiving a message notifying that the second cell group will be in a first state, and transitioning cells other than the second cell included in the second cell group to an inactive state based on the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0127] (4) A fourth embodiment of the present invention is a method applied to a base station device that communicates with a terminal device using a first cell group including a first cell and a second cell group including a second cell, comprising the steps of: transmitting a message notifying that the second cell group is in a first state; and generating the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0128] (5) A fifth embodiment of the present invention is an integrated circuit implemented in a terminal device that communicates using a first cell group including a first cell and a second cell group including a second cell, and that causes the terminal device to perform the functions of receiving a message notifying that the second cell group is to be set to a first state and transitioning cells other than the second cell included in the second cell group to an inactive state based on the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0129] (6) A sixth embodiment of the present invention is an integrated circuit implemented in a base station device that communicates with a terminal device using a first cell group including a first cell and a second cell group including a second cell, and causes the base station device to perform a function of transmitting a message notifying that the second cell group is in a first state and a function of generating the message, wherein the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell, and the first cell and the second cell are cells that support at least a physical uplink control channel and contention-based random access.

[0130] The program running on the device according to the present invention may be a program that controls a central processing unit (CPU) or the like to cause a computer to function so as to realize the functions of the above-described embodiments according to the present invention. The program or the information handled by the program is temporarily loaded into a volatile memory such as a random access memory (RAM) during processing, or stored in a nonvolatile memory such as a flash memory or a hard disk drive (HDD), and is read, modified, or written by the CPU as needed.

[0131] Note that a part of the device in the above-described embodiment may be realized by a computer. In this case, a program for realizing this control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed to realize the control function. The "computer system" here refers to a computer system built into the device, including hardware such as an operating system and peripheral devices. Furthermore, the "computer-readable recording medium" may be any of a semiconductor recording medium, an optical recording medium, a magnetic recording medium, etc.

[0132] Furthermore, the term "computer-readable recording medium" may also include a medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, or a medium that stores a program for a fixed period of time, such as volatile memory within a computer system that serves as a server or client in such cases. The program may also be one that realizes part of the above-mentioned functions, or one that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0133] Furthermore, each functional block or feature of the device used in the above-described embodiments may be implemented or performed by an electrical circuit, typically an integrated circuit or multiple integrated circuits. The electrical circuit designed to perform the functions described herein may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or a combination thereof. The general-purpose processor may be a microprocessor, or alternatively, the processor may be a conventional processor, controller, microcontroller, or state machine. The general-purpose processor or each of the aforementioned circuits may be composed of digital circuits or analog circuits. Furthermore, if advances in semiconductor technology result in the emergence of integrated circuit technologies that can replace current integrated circuits, integrated circuits based on that technology may also be used.

[0134] The present invention is not limited to the above-described embodiment. Although an example of a device has been described in the embodiment, the present invention is not limited to this and can be applied to terminal devices or communication devices such as stationary or non-movable electronic devices installed indoors or outdoors, for example, AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0135] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the gist of the present invention. Furthermore, the present invention is susceptible to various modifications within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, configurations in which elements described in the above embodiments are substituted with elements that achieve the same effect are also included. [Industrial Applicability]

[0136] The present invention can be used in, for example, communication systems, communication devices (for example, mobile phone devices, base station devices, wireless LAN devices, or sensor devices), integrated circuits (for example, communication chips), programs, and the like. [Explanation of symbols]

[0137] 100 E-UTRA 102 eNB 104 EPC 106 NR 108 gNB 110 5GC 112, 114, 116, 118, 120, 124 Interface 122UE 200, 300 PHY 202, 302 MAC 204, 304 RLC 206, 306 PDCP 208, 308 RRC 310 SDAP 210, 312 NAS 500,604 Receiver 502, 602 Processing section 504, 600 Transmitter

Claims

1. A terminal device that communicates using a first cell group including a first cell and a second cell group including a second cell, a receiving unit that receives a message notifying that the second cell group is to be set to a first state; a processing unit that transitions cells other than the second cell included in the second cell group to an inactive state based on the message; Equipped with the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell; When transitioning from the first state to another state, cells other than the second cell included in the second cell group are kept in an inactive state; the first cell and the second cell are cells that support at least a physical uplink control channel and a contention-based random access; Terminal device.

2. A base station device that communicates with a terminal device using a first cell group including a first cell and a second cell group including a second cell, a transmitter that transmits a message notifying that the second cell group is to be in a first state; a processing unit for generating the message; Equipped with the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell; When transitioning from the first state to another state, cells other than the second cell included in the second cell group are kept in an inactive state; the first cell and the second cell are cells that support at least a physical uplink control channel and a contention-based random access; Base station equipment.

3. A method applied to a terminal device that communicates using a first cell group including a first cell and a second cell group including a second cell, the method comprising: receiving a message indicating that the second cell group is to be placed in a first state; transitioning cells other than the second cell included in the second cell group to an inactive state based on the message; Equipped with the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell; When transitioning from the first state to another state, cells other than the second cell included in the second cell group are kept in an inactive state; the first cell and the second cell are cells that support at least a physical uplink control channel and a contention-based random access; method.

4. A method applied to a base station device that communicates with a terminal device using a first cell group including a first cell and a second cell group including a second cell, the method comprising: transmitting a message informing the second cell group of a first state; generating the message; Equipped with the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell; When transitioning from the first state to another state, cells other than the second cell included in the second cell group are kept in an inactive state; the first cell and the second cell are cells that support at least a physical uplink control channel and a contention-based random access; method.

5. An integrated circuit implemented in a terminal device that communicates using a first cell group including a first cell and a second cell group including a second cell, receiving a message informing the second cell group of a first state; a function of transitioning cells other than the second cell included in the second cell group to an inactive state based on the message; to the terminal device, the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell; When transitioning from the first state to another state, cells other than the second cell included in the second cell group are kept in an inactive state; the first cell and the second cell are cells that support at least a physical uplink control channel and a contention-based random access; Integrated circuit.

6. An integrated circuit implemented in a base station device that communicates with a terminal device using a first cell group including a first cell and a second cell group including a second cell, a function of transmitting a message notifying that the second cell group is in a first state; generating said message; to the base station device, the first state is a state in which the second cell is not in an inactive state and the terminal device does not monitor a physical downlink control channel in the second cell; When transitioning from the first state to another state, cells other than the second cell included in the second cell group are kept in an inactive state; the first cell and the second cell are cells that support at least a physical uplink control channel and a contention-based random access; Integrated circuit.

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