Wireless communication device, communication method, and communication program

Abstract

This wireless communication device (200) comprises a transmission unit (240) for transmitting a message to other wireless communication devices (100), and a processing unit (210) for carrying out processing on the message transmitted by the transmission unit (240). When including a first parameter in a first radio resource control (RRC) message that is transmitted to the other wireless communication devices (100) and including a second parameter in a first data radio bearer (DRB) configuration parameter that is included in the first RRC message, the processing unit (210) includes a third parameter in the first DRB configuration parameter.

Description

[Technical Field]

[0001] The present invention relates to a wireless communication device, a communication method, and a communication program. [Background technology]

[0002] In today's networks, wireless communication networks using mobile terminals (smartphones, feature phones, etc.) are expanding, and there is a demand for even faster and larger capacity wireless communication. One technology that achieves this is DC (Dual Connectivity). DC is a technology in which a terminal device wirelessly connects to multiple base station devices, including a master base station device and a secondary base station device, and performs wireless communication using the carriers of each base station device (hereinafter sometimes referred to as a "cell group").

[0003] Furthermore, as the generation of wireless communication standards advances, attention is being paid to MR-DC (Multi Radio Dual Connectivity), a DC technology that uses eNodeB (hereinafter sometimes referred to as "eNB"), a base station device that supports E-UTRA (Evolved Terrestrial Radio Access), which is a radio access technology (RAT: Radio Access Technology) for 3.9G, 4G (Fourth-Generation), and 4G-advanced, and gNodeB (hereinafter sometimes referred to as "gNB"), a base station device that supports NR (New Radio), which is a radio access technology for 5G (Fifth-Generation) and 5G-Advanced. Note that MR-DC also includes DC in which both the master base station device and the secondary base station device are gNBs.

[0004] In MR-DC, for example, when the amount of data to be transmitted and received is large, the terminal device transmits and receives data to and from both the master base station device and the secondary base station device. On the other hand, in MR-DC, for example, when the amount of data to be transmitted and received is small, the terminal device deactivates the cell group (secondary cell group) belonging to the secondary base station device, thereby temporarily suspending data transmission and reception with the secondary base station device, thereby saving power. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] 3GPP TS38.300 V16.8.0(2021-12) [Non-patent document 2] 3GPP TS37.340 V16.8.0(2021-12) [Non-patent document 3] 3GPP R2-2111638, "Introduction of efficient SCG activation / deactivation", 1-12 November 2021 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the procedure by which a base station device deactivates or activates a secondary cell group of a terminal device has not been determined as a standard specification. For example, when the secondary cell group of a terminal device is in an inactive state and control data transmission in each protocol occurs, it is necessary to activate the secondary cell group to transmit the control data, which results in unnecessary power consumption.

[0007] The disclosed technology has been made in consideration of the above points, and aims to provide a wireless communication device, a communication method, and a communication program that can suppress unnecessary increases in power consumption. [Means for solving the problem]

[0008] In one aspect, a wireless communication device disclosed in the present application includes a transmitter that transmits a message to another wireless communication device, and a processor that executes processing on the message transmitted by the transmitter. The processor includes a first parameter in a first Radio Resource Control (RRC) message transmitted to the other wireless communication device, and, when a second parameter is included in a first Data Radio Bearer (DRB) setting parameter included in the first RRC message, includes a third parameter in the first DRB setting parameter. [Effects of the Invention]

[0009] According to one aspect of the wireless communication device, communication method, and communication program disclosed in the present application, it is possible to suppress an unnecessary increase in power consumption. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a communication system. [Figure 2] FIG. 2 is a block diagram showing an example of the configuration of a base station device. [Figure 3] FIG. 3 is a block diagram showing an example of the configuration of a terminal device. [Figure 4] FIG. 4 is a diagram illustrating an example of a protocol stack of the U-Plane. [Figure 5] FIG. 5 is a diagram illustrating an example of a protocol stack of the C-Plane. [Figure 6] FIG. 6 is a diagram showing specific examples of parameters of an RRC message. [Figure 7] FIG. 7 is a diagram showing a specific example of parameters of an RRC message. [Figure 8] FIG. 8 is a diagram illustrating an example of the configuration of a cell group in a communication system. [Figure 9]FIG. 9 is a diagram illustrating the types of MR-DC. [Figure 10] FIG. 10 is a diagram illustrating the synchronized resetting. [Figure 11] FIG. 11 is a diagram illustrating transmission of an end marker control PDU. [Figure 12] FIG. 12 is a sequence diagram showing the transition operation to SCG deactivation. [Figure 13] FIG. 13 is a sequence diagram showing an RRC message transmission / reception operation during SCG deactivation. [Figure 14] FIG. 14 is a sequence diagram showing the SCG reactivation operation. [Figure 15] FIG. 15 is a diagram showing a specific example of mode transition. [Figure 16] FIG. 16 is a sequence diagram showing an RRC message transmission / reception operation during a radio bearer suspension. [Figure 17] FIG. 17 is a sequence diagram showing an RRC message transmission / reception operation for controlling uplink transmission. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of a wireless communication device, a communication method, and a communication program disclosed in the present application will be described in detail with reference to the drawings. The problems and embodiments in this specification are merely examples and do not limit the scope of the rights of the present application. In particular, even if the described expressions are different, if the embodiments are technically equivalent, the technology of the present application can be applied to those embodiments, and the scope of the rights is not limited by the following description.

[0012] [Example of communication system configuration] Fig. 1 is a diagram showing an example of the configuration of a communication system. The communication system shown in Fig. 1 includes a terminal device 100, base station devices 200-1 and 200-2, and a core network 300. This communication system may be a wireless communication system in which the terminal device 100 communicates with the base station device 200-1 or the base station device 200-2, or may be a wireless communication system in which the terminal device 100 communicates with the base station device 200-1 and the base station device 200-2 using MR-DC. For example, when communication is performed using MR-DC, the base station device 200-1 is a master base station device, and the base station device 200-2 is a secondary base station device. Hereinafter, the master base station device may be referred to as an MN (Master Node), and the secondary base station device may be referred to as an SN (Secondary Node).

[0013] The terminal device 100 is wirelessly connected to one or both of the base station devices 200-1 and 200-2 and performs wireless communication. The RAT (Radio Access Technology) that provides the wireless connection is, for example, E-UTRA or NR. The terminal device 100 is a tablet terminal or a smartphone that supports one or both of E-UTRA and NR.

[0014] Base station devices 200-1 and 200-2 (hereinafter, sometimes collectively referred to as "base station device 200") are wireless communication devices that are wirelessly connected to terminal device 100 and perform wireless communication. Base station devices 200-1 and 200-2 are, for example, connected to each other via a wire and perform communication. Base station device 200 is, for example, connected to core network 300 via a wire and performs communication. Base station device 200 corresponds to, for example, either an eNodeB when E-UTRA is the RAT or a gNodeB when NR is the RAT.

[0015] Core network 300 is a network corresponding to any generation of mobile communication systems. That is, core network 300 is, for example, a core network corresponding to 5G (hereinafter may be referred to as "5GC") or an EPC (Evolved Packet Core) corresponding to 4G.

[0016] The MR-DC realized in the communication system configured as above will be described in detail later.

[0017] [Configuration example of base station device 200] 2 is a block diagram showing an example of the configuration of the base station device 200. The base station device 200 is a communication device or a relay device including a processor 210, a storage 220, a memory 230, a wireless communication circuit 240, and a network interface (NI) 250.

[0018] The storage 220 is an auxiliary storage device such as a flash memory, a hard disk drive (HDD), or a solid state drive (SSD) that stores programs and data. The storage 220 stores a wireless communication program 221 and a base station side program 222.

[0019] The memory 230 is an area into which the programs stored in the storage 220 are loaded. The memory 230 may also be used as an area in which the programs store data.

[0020] The wireless communication circuit 240 is a circuit that wirelessly connects to and communicates with the terminal device 100. The base station device 200 receives signals transmitted from the terminal device 100 via the wireless communication circuit 240 and transmits signals to the terminal device 100.

[0021] The NI 250 is a communication device that connects to, for example, other base station devices 200 and realizes inter-base station communication. The NI 250 is also a communication device that connects to, for example, the core network 300 (communication devices that make up the core network 300) and performs communication. For example, a network interface card (NIC) can be used as the NI 250. The base station device 200 receives signals transmitted from other communication devices and transmits signals to other communication devices via the NI 250.

[0022] The processor 210 includes, for example, a CPU (Central Processing Unit) and loads programs stored in the storage 220 into the memory 230, executes the loaded programs, and configures each processing unit to realize various processes.

[0023] Specifically, the processor 210 performs wireless communication processing by executing the wireless communication program 221. This wireless communication processing is processing for wirelessly connecting to the terminal device 100, communicating wirelessly with the terminal device 100, and relaying communication between the terminal device 100 and other communication devices.

[0024] Furthermore, the processor 210 executes the base station side program 222 to configure a transmitting unit, a receiving unit, and a processing unit, and perform base station side processing. When the base station device 200 communicates with the terminal device 100 using MR-DC, the base station side processing may include MR-DC master node processing and MR-DC secondary node processing. In this case, the MR-DC master node processing is processing for controlling the master node side in MR-DC, and the MR-DC secondary node processing is processing for controlling the secondary node side in MR-DC. In the MR-DC master node processing and MR-DC secondary node processing, the base station device 200 performs communication corresponding to each type of MR-DC, which will be described later.

[0025] [Configuration example of terminal device 100] 3 is a block diagram showing an example of the configuration of the terminal device 100. The terminal device 100 is a communication device including a processor 110, a storage 120, a memory 130, and a wireless communication circuit 140.

[0026] The storage 120 is an auxiliary storage device such as a flash memory, HDD, or SSD that stores programs and data. The storage 120 stores a wireless communication program 121 and a terminal-side program 122.

[0027] The memory 130 is an area into which the programs stored in the storage 120 are loaded. The memory 130 may also be used as an area in which the programs store data.

[0028] The wireless communication circuit 140 is a circuit that wirelessly connects to and communicates with the base station device 200. The terminal device 100 receives signals transmitted from the base station device 200 via the wireless communication circuit 140 and transmits signals to the base station device 200. As the wireless communication circuit 140, for example, a network card compatible with wireless connections can be used.

[0029] The processor 110 loads a program stored in the storage 120 into the memory 130, executes the loaded program, and configures each processing unit to realize various processes.

[0030] Specifically, the processor 110 performs wireless communication processing by executing the wireless communication program 121. This wireless communication processing is processing for wirelessly connecting to the base station device 200, communicating wirelessly with the base station device 200, and communicating with other communication devices via the base station device 200.

[0031] Furthermore, the processor 110 executes the terminal-side program 122 to configure a transmitting unit and a receiving unit processing unit, and perform terminal-side processing. When the terminal device 100 communicates with the base station device 200 using MR-DC, the terminal-side processing may include terminal-side MR-DC processing. In this case, the terminal-side MR-DC processing is processing for controlling communication in MR-DC. In the terminal-side MR-DC processing, the terminal device 100 performs communication corresponding to each type of MR-DC, which will be described later.

[0032] [Protocol stack] An example of a protocol stack for a communication system will be described. In a communication system, a series of protocols for transmitting and receiving data, shown in a hierarchical structure, is called a protocol stack. In the following, a case will be described in which the base station device 200 is an eNB or a gNB, and the core network 300 is an EPC or a 5GC. Furthermore, the terminal device 100 (UE: User Equipment) is assumed to support one or both of E-UTRA and NR.

[0033] The protocol stacks of the U-Plane (User Plane) and C-Plane (Control Plane) will be explained below. The U-Plane corresponds to, for example, data signals (messages) of user data that are transmitted and received. The C-Plane corresponds to, for example, control signals (messages) that are transmitted and received in communications.

[0034] FIG. 4 is a diagram showing an example of a protocol stack for the U-Plane when the core network 300 is 5GC. FIG. 5 is a diagram showing an example of a protocol stack for the C-Plane when the core network 300 is 5GC. In FIGS. 4 and 5, SDAP, PDCP, RLC, MAC, PHY, NAS, and RRC indicate the names of layers. Hereinafter, SDAP, PDCP, RLC, MAC, PHY, NAS, and RRC may each be referred to as a sublayer or layer, such as an "SDAP sublayer" or an "SDAP layer." SDAP, PDCP, RLC, MAC, PHY, NAS, and RRC may each be referred to as an entity, such as an "SDAP entity." Note that when the core network 300 is an EPC, the U-Plane protocol stack is the protocol stack in FIG. 4 without the SDAP. That is, when the core network 300 is an EPC, the U-Plane protocol stack consists of PDCP, RLC, MAC, and PHY. Furthermore, in the case where the core network 300 is an EPC, the protocol stack of the C-Plane is such that the NAS shown in FIG. 5 exists in an MME (Mobility Management Entity) instead of an AMF.

[0035] The functions in each layer may be common or different between E-UTRA and NR RATs. In the following, unless E-UTRA or NR is specified, the explanation will be about functions common to E-UTRA and NR.

[0036] In Figure 4, the U-Plane is composed of SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control) and PHY (PHYsical), and terminates at the terminal device 100 (UE) and the base station device 200 (gNB).

[0037] PHY is a wireless physical layer, and transmits control information and data between the terminal device 100 and the base station device 200 using a physical channel. Hereinafter, the direction from the base station device 200 to the terminal device 100 may be referred to as downlink (downlink, DL), and the direction from the terminal device 100 to the base station device 200 may be referred to as uplink (uplink, UL). Furthermore, within the terminal device 100 and the base station device 200, PHY is connected to MAC, which is an upper layer, by a transport channel, and data moves between PHY and MAC via the transport channel.

[0038] MAC is a medium access control layer, and performs mapping between transport channels and logical channels (LCHs), multiplexing / demultiplexing of MAC SDUs, scheduling reports, error correction through HARQ (Hybrid Automatic Repeat reQuest), priority control, etc. Within the terminal device 100 and the base station device 200, MAC is connected to the upper layer RLC by a logical channel, and data moves between MAC and RLC via the logical channel.

[0039] Here, SDU (Service Data Unit) refers to data passed from a higher sublayer or data passed to a higher layer in each sublayer. Furthermore, PDU (Protocol Data Unit) refers to data passed from a lower sublayer or data passed to a lower sublayer in each sublayer. Furthermore, RLC, PDCP, and SDAP have control PDUs, which are sometimes called control PDUs. Furthermore, other PDUs are sometimes called data PDUs to distinguish them from control PDUs.

[0040] RLC is a radio link control layer and has three modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). TM RLC is sometimes called TM RLC, UM RLC, and AM RLC. On the transmitting side, RLC performs functions such as transmitting PDCP PDUs, assigning sequence numbers (in the case of UM or AM), and segmenting (in the case of UM or AM) and re-segmenting (in the case of AM). On the receiving side, RLC performs functions such as reassembling SDUs (in the case of UM or AM), detecting duplicates (in the case of AM), and discarding RLC SDUs (in the case of UM or AM). Furthermore, RLC performs functions such as RLC re-establishment on the transmitting and receiving sides. In E-UTRA, RLC also performs data combining on the transmitting side and reordering and in-order delivery on the receiving side. An example of a control PDU used in RLC is a status PDU, which is a control PDU used by the receiving side of an AM RLC entity to report to the corresponding AM RLC entity which RLC data PDUs were successfully received and which were not (i.e., loss was detected) received.

[0041] PDCP is a packet data convergence protocol layer that performs functions such as U-Plane and C-Plane data transfer, PDCP sequence number management, header compression / decompression, encryption / decryption, integrity protection / verification, timer-based SDU discard, routing for split bearers, reordering, and in-order delivery. In the case of E-UTRA, PDCP functions such as timer-based SDU discard, reordering, and in-order delivery may be limited to split bearers. The control PDU used in PDCP is, for example, the PDCP status report. The PDCP status report is transmitted in the uplink (UL) direction to an AM DRB (described later) configured by the upper layer (RRC layer) for PDCP status report transmission when, for example, PDCP entity re-establishment or PDCP data recovery is requested.

[0042] Here, the PDCP entity re-establishment process includes the following processes. Initialization of state variables in UM DRB (described later) and SRB (described later) - Applying security algorithms and security keys provided by upper layers - Transmission of data that has not been completed and / or successfully transmitted by the sender - PDCP status report transmission (if PDCP status report transmission is configured) The PDCP data recovery process also includes the following: - Sending data that has not been sent successfully on the sending side - PDCP status report transmission (if PDCP status report transmission is configured)

[0043] SDAP is a service data adaptation protocol layer that maps Quality of Service (QoS) flows to Data Radio Bearers (DRBs) and marks downlink (DL) and uplink (UL) packets with QoS Flow Identifiers (QFIs). The control PDUs used in SDAP include the end marker control PDU.

[0044] The upper layers of the U-Plane include, for example, IP (Internet Protocol), TCP (Transmission Control Protocol), UDP (User Datagram Protocol), Ethernet (registered trademark), and application layers. The IP, TCP, UDP, and Ethernet layers may be included in the PDU layer. Furthermore, the IMS (IP Multimedia Subsystem) may be included in the application layer.

[0045] 5, the C-Plane of the AS (Access Stratum) is composed of RRC (Radio Resource Control), PDCP, RLC, MAC, and PHY, and terminates at the terminal device 100 and the base station device 200. The C-Plane of the NAS (Non Access Stratum) is composed of the NAS, and terminates between the terminal device 100 and the AMF (Access and Mobility management Function), which is a device in the core network 300. PDCP, RLC, MAC, and PHY are the same as those in the U-Plane.

[0046] The RRC performs functions such as broadcasting system information (SI) related to AS and NAS, paging, establishing / maintaining / releasing RRC connections between the terminal device 100 and the base station device 200, adding / changing / releasing carrier aggregation (CA), adding / changing / releasing dual connectivity (DC), security functions including management of security keys, establishing / setting / maintaining / releasing signaling radio bearers (SRBs) and data radio bearers (DRBs), mobility functions, QoS management functions, controlling terminal device measurement reports and reporting, detecting and recovering from radio link failures (RLFs), and forwarding NAS messages.

[0047] The NAS performs authentication, mobility management, security control, etc. As described above, when the device of the core network 300 is an EPC, the NAS terminates between the terminal device 100 and the MME, which is a device of the core network 300.

[0048] [channel] The channels used in the communication system will be described below. Although examples of channels corresponding to NR are shown below, the channels used are not limited to the following. Furthermore, channels with the same names may be used for the same or similar purposes in RATs other than NR (e.g., E-UTRA).

[0049] -1. Physical Channel- The PBCH (Physical Broadcast CHannel) is a channel used for transmitting broadcast information from the base station device 200 to the terminal device 100.

[0050] The PDCCH (Physical Downlink Control CHannel) is a channel used for transmitting downlink control information (DCI) and the like from the base station device 200 to the terminal device 100.

[0051] The PDSCH (Physical Downlink Shared CHannel) is a channel used for transmitting data from an upper layer from the base station device 200 to the terminal device 100.

[0052] The PUCCH (Physical Uplink Control CHannel) is a channel used for transmitting uplink control information (UCI) and the like from the terminal device 100 to the base station device 200.

[0053] A PUSCH (Physical Uplink Shared CHannel) is a channel used for transmitting data from an upper layer from the terminal device 100 to the base station device 200.

[0054] The PRACH (Physical Random Access CHannel) is a channel used for transmitting a random access preamble and the like from the terminal device 100 to the base station device 200.

[0055] -2.Transport Channel- The BCH (Broadcast CHannel) is mapped to the PBCH, which is a physical channel.

[0056] The DL-SCH (Downlink Shared CHannel) is mapped to the PDSCH, which is a physical channel.

[0057] The PCH (Paging CHannel) is mapped to the PDSCH, which is a physical channel.

[0058] The UL-SCH (Uplink Shared CHannel) is mapped to the PUSCH, which is a physical channel.

[0059] Random Access CHannel(s) (RACH) are mapped to PRACH, which is a physical channel.

[0060] -3. Logical Channel- The BCCH (Broadcast Control CHannel) is a downlink channel for broadcasting system information, and is mapped to the BCH, which is a transport channel.

[0061] A PCCH (Paging Control CHannel) is a downlink channel for carrying paging messages and is mapped to the PCH of the transport channel.

[0062] The CCCH (Common Control CHannel) is a channel for transmitting control information (such as RRC messages) between the terminal device 100 and the base station device 200, and is a channel used for the terminal device 100 that does not maintain (does not have) an RRC connection with the base station device 200, with the downlink mapped to the transport channel DL-SCH and the uplink mapped to the transport channel UL-SCH.

[0063] The DCCH (Dedicated Control CHannel) is a point-to-point bidirectional channel that transmits dedicated control information (such as RRC messages) between the terminal device 100 and the base station device 200, and is a channel used for the terminal device 100 that has an RRC connection with the base station device 200, with the downlink mapped to the transport channel DL-SCH and the uplink mapped to the transport channel UL-SCH.

[0064] DTCH (Dedicated Transport CHannel) is a point-to-point bidirectional channel dedicated to a terminal, which transmits user information (user data). The downlink is mapped to the transport channel DL-SCH, and the uplink is mapped to the transport channel UL-SCH.

[0065] [RRC message] The RRC message will now be described. The RRC message is a message that includes information necessary for communication in a cell, and includes a MIB (Master Information Block) and a SIB (System Information Block), etc. Parameters included in the RRC message are sometimes called fields or information elements (IEs).

[0066] The base station device 200 transmits an RRC message to the terminal device 100, thereby causing the terminal device 100 to perform processing in accordance with the RRC message. Furthermore, the terminal device 100 receives an RRC message from the base station device 200, thereby performing processing in accordance with the RRC message. Furthermore, the terminal device 100 transmits an RRC message to the base station device 200, thereby requesting transmission of an RRC message from the base station device 200. Furthermore, the terminal device 100 transmits an RRC message to the base station device 200, thereby notifying that processing in accordance with the RRC message received from the base station device 200 has been completed.

[0067] The RRC messages include messages related to the establishment of an RRC connection. For example, in the case of NR, messages related to the establishment of an RRC connection include an RRC setup request message (RRCSetupRequest), an RRC setup message (RRCSetup), and an RRC setup complete message (RRCSetupComplete). For example, in the case of E-UTRA, messages related to the establishment of an RRC connection include an RRC connection setup request message (RRCConnectionSetupRequest), an RRC connection setup message (RRCConnectionSetup), and an RRC connection setup complete message (RRCConnectionSetupComplete).

[0068] The RRC message also includes a message related to the initial activation of AS (Access Stratum) security. Examples of messages related to the initial activation of AS security include a security mode command message (SecurityModeCommand).

[0069] The RRC message also includes a message related to the reconfiguration of the RRC connection. For example, in the case of NR, the message related to the reconfiguration of the RRC connection includes an RRC reconfiguration message (RRCReconfiguration) and an RRC reconfiguration complete message (RRCReconfigurationComplete). For example, in the case of E-UTRA, the message related to the reconfiguration of the RRC connection includes an RRC connection reconfiguration message (RRCConnectionReconfiguration) and an RRC connection reconfiguration complete message (RRCConnectionReconfigurationComplete).

[0070] 6 and 7 are diagrams showing specific examples of parameters of an RRC message. In Fig. 6, format E1 is a parameter of an RRC reconfiguration message.

[0071] The RRC reconfiguration message has radioBearerConfig, radioBearerConfig2, masterCellGroup, secondaryCellGroup, masterKeyUpdate, and sk-counter as parameters.

[0072] radioBearerConfig and radioBearerConfig2 are settings related to MN-terminated bearers or SN-terminated bearers, and include SRB settings, DRB settings, and security settings. The SRB settings (DRB settings) include an SRB identifier (DRB identifier), PDCP settings, a parameter instructing PDCP re-establishment, and a parameter instructing PDCP data recovery. The security settings include a parameter (keyToUse) indicating whether to use a master key or a secondary key. The PDCP settings also include a parameter indicating the primary path when multiple RLCs are associated (for example, in the case of a split bearer), and a parameter for setting PDCP status report transmission.

[0073] The masterCellGroup and secondaryCellGroup are MCG configuration and SCG configuration, respectively, and include a cell group identifier, an RLC bearer configuration, an SpCell configuration, etc. The RLC bearer configuration includes a logical channel identifier, an RLC configuration, a radio bearer identifier (SRB identifier or DRB identifier) ​​to which the RLC bearer is associated, etc. The SpCell configuration includes information necessary for synchronized reconfiguration, etc.

[0074] masterKeyUpdate contains the information needed to update the master key.

[0075] The sk-counter contains the information necessary to generate the secondary key.

[0076] Format E11 shown in Fig. 6 is a diagram illustrating an example of parameters of RadioBearerConfig included in the RRC reconfiguration message, and format E12 is a diagram illustrating an example of parameters of CellGroupConfig included in the RRC reconfiguration message.

[0077] Format E111 shown in Fig. 7 is a diagram showing example parameters of SRB-ToAddMod included in RadioBearerConfig of format E11. Format E112 is a diagram showing example parameters of DRB-ToAddMod included in RadioBearerConfig of format E11. Format E113 is a diagram showing example parameters of SecurityConfig included in RadioBearerConfig of format E11.

[0078] 7 shows an example of parameters of RLC-BearerConfig included in CellGroupConfig of format E12. Also, format E122 shows an example of parameters of SpCellConfig included in CellGroupConfig of format E12.

[0079] The messages related to the reconfiguration of the RRC connection include the establishment, configuration, modification or release of radio bearers and cell groups, and synchronized reconfiguration, as well as the establishment, configuration, modification or release of measurement information.

[0080] The RRC messages also include messages regarding re-establishment of an RRC connection, messages regarding release and suspension of an RRC connection, messages regarding resumption of an RRC connection, messages regarding the capabilities of a terminal device, messages regarding terminal information, and messages regarding failure information of an MCG or SCG.

[0081] In addition, when the master node in MR-DC is an eNB, the eNB may perform NR-related configuration on the terminal device 100 by including an NR RRC message and parameters received from a gNB, which is a secondary node, as a container in an E-UTRA RRC message and transmitting the message to the terminal device 100. In addition, the terminal device 100 may include a completion message for NR-related configuration as a container in an E-UTRA RRC message and transmit the message to the eNB, which is the master node.

[0082] Furthermore, when the master node in MR-DC is a gNB, the gNB may perform E-UTRA-related configuration on the terminal device 100 by including an E-UTRA RRC message and parameters received from the eNB, which is the secondary node, as a container in an NR RRC message and transmitting the message to the terminal device 100. Furthermore, the terminal device 100 may include a completion message for E-UTRA-related configuration as a container in an NR RRC message and transmit the message to the gNB, which is the master node.

[0083] [Radio Bearer] An example of a radio bearer in a communication system will now be described.

[0084] -1. Signaling Radio Bearer- A signaling radio bearer (SRB) is a radio bearer for transmitting RRC messages and NAS messages.

[0085] SRB0 is a radio bearer for RRC messages that uses the CCCH logical channel. SRB1 is a radio bearer for RRC messages and NAS messages that uses the DCCH logical channel before SRB2, which will be described later, is established. SRB2 is a radio bearer for NAS messages and RRC messages that include logged measurement information, and uses the DCCH logical channel. The priority of SRB2 is lower than the priority of SRB1, and may be set by the base station device 200 after AS security is activated. SRB3 is a radio bearer for RRC messages when EN-DC, NGEN-DC, or NR-DC is set in the terminal device 100, and uses the DCCH logical channel. EN-DC, NGEN-DC, and NR-DC are types of MR-DC, and will be described in detail later.

[0086] -2. Data Radio Bearer- A data radio bearer (DRB) is a radio bearer for transmitting user data.

[0087] [SRB and DRB protocol configuration] SRB1 and SRB2 consist of one PDCP and one or more RLC bearers. An RLC bearer consists of an RLC and MAC logical channel. A MAC exists for each cell group described below. The RLC mode is AM. SRB3 consists of one PDCP and one RLC bearer. The RLC mode is AM.

[0088] A DRB consists of one PDCP and one or more RLC bearers. The RLC mode is UM or AM. A DRB may be called a UM DBR when the RLC is UM, or an AM DRB when the RLC is AM. Furthermore, a DRB is associated with one SDAP when the core network 300 is a 5GC, and is associated with one EPS (Evolved Packet System) bearer (or EPS bearer identifier) ​​when the core network 300 is an EPC.

[0089] 5GC is a core network standardized for 5G, and is described in, for example, 3GPP specifications such as TS 23.501 and TS 23.502. On the other hand, EPC is a core network standardized for 4G, and is described in, for example, 3GPP specifications such as TS 23.401 and TS 23.402.

[0090] [Cell Group] A cell group (CG) indicates a configuration of cells in an MR-DC. In an MR-DC, cell groups are classified into a master cell group (MCG) and a secondary cell group (SCG).

[0091] Fig. 8 is a diagram showing an example of the configuration of a cell group in a communication system. In Fig. 8, the master node (MN) is the base station device 200-1, and the secondary node (SN) is the base station device 200-2. The master node provides a C-Plane connection to the core network 300 in MR-DC. The secondary node does not provide a C-Plane to the core network 300 in MR-DC, but provides additional radio resources to the terminal device 100.

[0092] A CG consists of one special cell (SpCell), or one SpCell and one or more secondary cells (SCells). The SpCell in an MCG is sometimes called a primary cell (PCell), and the SpCell in an SCG is sometimes called a primary SCG cell (PSCell).

[0093] In the example shown in Figure 8, the MCG is composed of one PCell and two SCells. Also, in the example shown in Figure 8, the SCG is composed of one PSCell and two SCells. The MCG is a CG when MR-DC is not configured, or a CG that belongs to the master node when MR-DC is configured. The SCG is a CG that belongs to the secondary node when MR-DC is configured.

[0094] In the MCG, the PCell is a cell that operates on the primary frequency and is used for an initial connection establishment procedure or a connection re-establishment procedure of the terminal device 100. The connection establishment / re-establishment procedure includes a random access procedure.

[0095] The PSCell is a cell used in the SCG for a random access procedure when the terminal device 100 executes reconfiguration with synchronization (Reconfiguration With Sync), etc.

[0096] The SCell is a cell that provides additional radio resources in addition to the SpCell to the terminal device 100 in which carrier aggregation is configured.

[0097] [MR-DC type] The types of MR-DC will be described below. MR-DC is classified into four types depending on the type (corresponding generation) of the base station device 200 of the master node and secondary node and the type (corresponding generation) of the core network 300.

[0098] Fig. 9 is a diagram for explaining types of MR-DC. Each type of MR-DC will be explained below. In Fig. 9, the master node is the base station device 200-1, and the secondary node is the base station device 200-2. Also, in Fig. 9, thin solid lines indicate U-Plane connections, dashed lines indicate C-Plane connections, and thick solid lines indicate inter-base station interfaces.

[0099] 9A is a diagram illustrating an example of an EN-DC (E-UTRA-NR DC). The EN-DC is an MR-DC in which the base station device 200-1 serving as the master node is an E-UTRA eNB, the base station device 200-2 serving as the secondary node is an NR gNB, and the core network 300 is an EPC.

[0100] 9(b) is a diagram showing an example of NGEN-DC (NG-RAN E-UTRA-NR DC). NGEN-DC is an MR-DC in which the master node (base station device 200-1) is an eNB, the secondary node (base station device 200-2) is a gNB, and the core network 300 is 5GC.

[0101] 9(c) is a diagram illustrating an example of an NE-DC (NR-E-UTRA DC). The NE-DC is an MR-DC in which the master node (base station device 200-1) is a gNB, the secondary node (base station device 200-2) is an eNB, and the core network 300 is 5GC.

[0102] 9(d) is a diagram showing an example of NR-DC (NR-NR DC). NR-DC is an MR-DC in which the master node (base station device 200-1) is a gNB, the secondary node (base station device 200-2) is another gNB, and the core network 300 is 5GC.

[0103] EN-DC and NGEN-DC are sometimes called (NG)EN-DC. The secondary node of EN-DC is sometimes called en-gNB. The master node of NGEN-DC is sometimes called ng-eNB.

[0104] 9, it is assumed that SRB1 and SRB2 are established as C-Plane interfaces between the terminal device 100 and the base station device 200-1. When split SRB1, split SRB2, or SRB3 is established, some C-Plane messages may be transmitted and received between the secondary node and the terminal device 100. Some C-Plane messages received at the secondary node are transmitted to the master node via the inter-base station interface. Some C-Plane messages transmitted from the secondary node are transmitted from the master node to the secondary node via the inter-base station interface.

[0105] [MR-DC bearer type] This section explains the bearer types in MR-DC. Hereinafter, a configuration in which PDCP terminates at the master node and the master node has a PDCP may be referred to as MN-terminated. Also, a configuration in which PDCP terminates at the secondary node and the secondary node has a PDCP may be referred to as SN-terminated. Bearer types are classified into the following six types. (A) MN-terminated MCG bearer with RLC bearer on MCG side (B) MN-terminated, split bearer where the RLC bearer exists in both the MCG and SCG (C) MN-terminated SCG bearer with RLC bearer existing on SCG side (D) SN-terminated MCG bearer with RLC bearer existing on MCG side (E) SN-terminated split bearer in which the RLC bearer exists in both the MCG and SCG (F)SN-terminated SCG bearer with RLC bearer existing on SCG side

[0106] A DRB is configured with one of the six bearer types listed above.

[0107] SRB1 and SRB2 are configured as MN-terminated MCG bearers ((A) above) or MN-terminated split bearers ((B) above). When SRB1 and SRB2 are configured as MN-terminated split bearers, they may be called Split SBR1 and Split SBR2, respectively.

[0108] SBR3 is configured with an SN-Terminated SCG bearer ((F) above).

[0109] Furthermore, in the case of a split bearer, a primary path is set. The primary path indicates the base station device 200 to which the terminal device 100 initially transmits data (preferentially). The primary path is specified by a cell group (MCG or SCG) and an LCH. The terminal device 100 transmits data to the base station device 200 of the primary path as long as the amount of transmission data of uplink data does not exceed a predetermined threshold. If the amount of transmission data exceeds the predetermined threshold, the terminal device 100 may transmit data to either base station device 200.

[0110] In addition, the security keys used in PDCP differ between the MN-Terminated case (master key) and the SN-Terminated case (secondary key).

[0111] [Reconfiguration with synchronization (handover)] Reconfiguration with Sync (handover) will now be described. Reconfiguration with Sync is a procedure executed in the terminal device 100 by including a parameter indicating that reconfiguration with Sync is to be performed (reconfigurationWithSync: hereinafter, may be referred to as a "reconfiguration parameter with Sync") in an RRC reconfiguration message transmitted from the base station device 200 to the terminal device 100.

[0112] 10 is a diagram illustrating synchronized reconfiguration. A terminal device (UE) 100 changes the PCell to be connected from the current source PCell to a target PCell (step S1). Synchronized reconfiguration parameters are separately included in parameters for MCG configuration (hereinafter may be referred to as "MCG configuration parameters") or parameters for SCG configuration (hereinafter may be referred to as "SCG configuration parameters"). In other words, when synchronized reconfiguration parameters are included in MCG configuration parameters, synchronized reconfiguration of MCG is performed, and when synchronized reconfiguration parameters are included in SCG configuration parameters, synchronized reconfiguration of SCG is performed.

[0113] Synchronized reconfiguration is a procedure in which the terminal device 100 changes the PCell or PSCell, and includes operations such as random access to the new (change-to, target) PCell or PSCell, MAC reset, and PDCP data recovery (in the case of AM DRB). Synchronized reconfiguration may also involve a change of security key. In this case, in addition to the above operations, a PDCP entity reestablishment is performed. Note that in the present embodiment, PDCP entity reestablishment may also be referred to as PDCP reestablishment. When a security key is changed, a new key is generated in the RRC entity of the terminal device 100, and the PDCP entity is reestablished, and the new key is applied to the PDCP entity.

[0114] [QoS flow remapping in SDAP] When the DRB to which a QoS flow maps is changed in the terminal device 100, an end marker control PDU is transmitted to the DRB before the change. QoS flows are service data flows (SDFs) with the same QoS requirements and are identified by a QoS flow identifier (QFI). The SDF may be, for example, an IP flow or an Ethernet flow, and may differ depending on the upper layer.

[0115] 11 is a diagram illustrating the transmission of an end marker control PDU. For example, in the terminal device 100, the DRB associated with QoS flow 1 is changed from DRB1 to DRB2 (step S2). At this time, the terminal device 100 transmits the data of QoS flow 1 that has been retained before the change is instructed, using the previous DRB1. Then, the terminal device 100 transmits, using the DRB1, an end marker control PDU indicating that the data of QoS flow 1 will be transmitted for the last time using DRB1. This allows the base station device 200 to recognize that data of QoS flow 1 will no longer be transmitted using the previous DRB1. Note that the association between a QoS flow and a DRB may be performed using parameters included in an RRC reconfiguration message or header information included in a downlink SDAP data PDU. The latter is called reflective mapping.

[0116] [RRC state (mode)] The RRC state of the terminal device 100 indicates a state related to the RRC connection of the terminal device 100. A state in which an RRC connection with the base station device 200 is not established may be called an RRC idle mode (RRC_IDLE). A state in which an RRC connection with the base station device 200 is established may be called an RRC connected mode (RRC_CONNECTED). A state in which the RRC connection with the base station device 200 is temporarily suspended may be called an RRC inactive mode (RRC_INACTIVE). Note that when the core network 300 is an EPC, the state in which the RRC connection with the base station device 200 is temporarily suspended may be called by another name, such as RRC suspended.

[0117] The transition from the RRC idle mode to the RRC connected mode may be performed by transmitting and receiving a message related to the establishment of an RRC connection between the terminal device 100 and the base station device 200. For example, in NR, the terminal device 100 may transition to the RRC connected mode by transmitting an RRC setup request message to the base station device 200 and receiving an RRC setup message from the base station device 200 in response. Note that the RRC setup request message and the RRC setup message may be transmitted and received using a CCCH logical channel. Also, the cell used for transmitting and receiving the RRC setup request message and the RRC setup message may be the PCell.

[0118] The terminal device 100 that has transitioned to the RRC connection mode further receives a message regarding the initial activation of AS security and a message regarding the re-establishment of the RRC connection from the base station device 200, and performs configuration according to the messages, thereby enabling transmission and reception of user data (for example, IP packets, Ethernet frames, etc.). In addition, carrier aggregation and MR-DC may be configured by the message regarding the re-establishment of the RRC connection. Note that the message regarding the initial activation of AS security and the message regarding the re-establishment of the RRC connection may be transmitted and received using the DCCH logical channel.

[0119] The transition from the RRC connected mode to the RRC inactive mode may be performed by the terminal device 100 transmitting and receiving a message related to the release of the RRC connection, including parameters related to the suspension setting of the RRC connection, from the base station device 200. FIG. 15(a) is a diagram showing a transition procedure from the RRC connected mode to the RRC inactive mode when the base station device 200 is a gNB (in the case of MR-DC, the master node is a gNB) and the core network 300 is 5GC. The base station device 200 sends to the terminal device 100 a message related to the release of the RRC connection (RRCRelease) including parameters related to the suspension setting of the RRC connection (suspendConfig). The terminal device 100 transitions to the RRC inactive mode by performing processing in accordance with the received RRC release message. Note that the RRC release message may be sent using the DCCH logical channel.

[0120] When transitioning to the RRC inactive mode, the terminal device 100 may perform processing including saving the UE inactive AS context and suspending radio bearers other than SRB0. The UE inactive AS context is a setting including the current security key (immediately before transitioning to the RRC inactive mode) of the terminal device 100, a state related to header compression, a correspondence between a QoS flow and a DRB, a C-RNTI (Cell Radio Network Temporary Identifier) ​​in the source (handover source) PCell, and the like. Furthermore, when MR-DC is configured in the terminal device 100, a setting related to the SCG may be saved as the UE inactive AS context. Note that some of the parameters related to handover such as synchronized reconfiguration and some of the parameters set in the SIB may be excluded from the setting saved as the UE inactive AS context.

[0121] A transition from RRC inactive mode to RRC connected mode may be performed by transmitting and receiving a message related to RRC connection resumption between the terminal device 100 and the base station device 200. FIG. 15(b) is a diagram showing a transition procedure from RRC inactive mode to RRC connected mode when the base station device 200 is a gNB (in the case of MR-DC, the master node is a gNB) and the core network 300 is 5GC. The terminal device 100 may transition to the RRC connected mode by sending an RRC resumption request message (RRCResumeRequest) to the base station device 200, receiving an RRC resumption message (RRCResume) from the base station device 200 in response thereto, and performing processing in accordance with the received RRC resumption message. When the terminal device 100 has saved a configuration related to the SCG as a UE inactive AS context and SCG retention upon RRC resumption is set, the base station device 200 may include an SCG configuration in the RRC resumption message and may include a synchronized reconfiguration of the SCG in the SCG configuration. The RRC resumption request message is transmitted using, for example, the CCCH logical channel, and the RRC resumption message is transmitted using, for example, the DCCH logical channel.

[0122] [SCG failure information] When the terminal device 100 detects an SCG failure when MR-DC is configured, it may send a message (SCGFailureInformation) related to SCG failure information to the master node via the MCG. SCG failure may be detected, for example, when the SCG side loses physical layer synchronization, when random access fails on the SCG side, when the number of RLC retransmissions on the SCG side exceeds a predetermined threshold, when SCG synchronized reconfiguration fails, when processing according to the SCG configuration cannot be performed, or when SRB3 integrity verification fails. When transmitting the message related to SCG failure information, the terminal device 100 may perform processing including suspending SCG transmission for all radio bearers, i.e., suspending transmission of all radio bearers associated with the SCG. Note that in the case of (NG)EN-DC, SCGFailureInformationNR may be sent instead of SCGFailureInformation. SCGFailureInformation and SCGFailureInformationNR are transmitted, for example, using the DCCH logical channel.

[0123] When the base station device 200 receives a message regarding SCG failure information from the terminal device 100, it may transmit a message regarding RRC connection reconfiguration to the terminal device 100 in order to reconfigure the SCG.

[0124] [SCG inactive] In an (NG)EN-DC or NR-DC, communication between a secondary node and the terminal device 100 may be restricted by deactivating the SCG set in the terminal device 100 (SCG deactivation). Hereinafter, when an SCG is in an inactive state (also referred to as a "deactivation state" or "deactivated state"), it may be referred to as "in SCG deactivation." Furthermore, when an SCG is in an activated state (also referred to as an "activation state" or "activated state"), it may be referred to as "in SCG (re)activation." Furthermore, when an SCG is in an inactive state, it may be referred to as SCG deactivation. Furthermore, when an SCG in an inactive state is activated, it may be referred to as SCG (re)activation. Furthermore, hereinafter, "reactivation" and "reactivate" are assumed to include "activation" and "activate," respectively.

[0125] The terminal device 100 undergoing SCG deactivation satisfies some or all of the following conditions. When a message (for example, an RRC reconfiguration message) regarding the reconfiguration of the RRC connection of the SCG is received from the base station device 200, the SCG executes processing according to this message. - No uplink transmission on the SCG side · Processing of uplink data on the SCG side may be performed PDCCH monitoring (reception) is not performed in the PSCell · SCG side PUSCH is not transmitted

[0126] In addition, if the message regarding the reconfiguration of the RRC connection received from the base station device 200 includes a parameter indicating SCG deactivation and also includes a parameter regarding synchronized reconfiguration of the SCG, the terminal device 100 will not perform random access processing in at least the SCG.

[0127] Note that the terminal device 100 undergoing SCG deactivation may perform communication in the RRC connected mode with the base station device 200 using the MCG.

[0128] (Embodiment 1) A first embodiment will be described. In communication between a terminal device 100 and a secondary node (base station device 200), a communication system appropriately controls switching from during SCG deactivation to during SCG (re)activation, or switching from during SCG (re)activation to during SCG deactivation. Appropriate control means, for example, control to prevent unnecessary switching or postpone the timing of switching until a necessary timing in order to achieve power saving. In communication between a terminal device 100 and a secondary node (base station device 200), the communication system controls to prevent unnecessary uplink transmission from being performed during SCG deactivation, thereby achieving power saving.

[0129] [Transition process to SCG deactivation] FIG. 12 is a sequence diagram showing a transition operation to SCG deactivation. The base station device 200 is, for example, a master node in MR-DC. MR-DC in FIG. 12 includes, for example, (NG)EN-DC and NR-DC. Although there is only one base station device 200 in the sequence of FIG. 12, there may be multiple base station devices 200, including a master node and a secondary node. In addition, in the sequence of FIG. 12, messages transmitted and received by the base station device 200 may be transmitted and received by either the master node or the secondary node. When the master node executes the processing executed by the base station device 200 in FIG. 12, a message transmitted from the terminal device 100 to the secondary node is transmitted to the master node via inter-base station communication. Furthermore, the processing executed by the base station device 200 may be executed by either the master node or the secondary node. To satisfy the above-described conditions, the terminal device 100 does not transmit a message to the secondary node and does not receive a PDCCH from the secondary node during SCG deactivation.

[0130] 12, the terminal device 100 configures an SCG (step S101) and is in the process of SCG (re)activation. The SCG configuration is performed by the terminal device 100 receiving an RRC reconfiguration message including SCG configuration parameters from the base station device 200. The SGC configuration parameters include, for example, NR SGC configuration parameters.

[0131] The terminal device 100 transmits a terminal information notification to the base station device 200 (step S102). The terminal information notification is, for example, an RRC message or a parameter included in the RRC message. The terminal information notification may be, for example, UE assistance information in an RRC message, or may be a message with another name. The terminal information notification includes, for example, information indicating whether or not power saving is necessary in the terminal device 100. The terminal device 100 determines whether or not power saving is necessary according to, for example, the remaining battery level.

[0132] The terminal information notification also includes, for example, information indicating whether SCG deactivation (or SCG release) is necessary. The terminal device 100 determines the necessity of SCG deactivation, for example, according to the amount of communication (data communication amount) with the secondary node. The terminal information notification may also include information indicating whether to immediately execute SCG synchronized reconfiguration parameters when they are received during SCG deactivation (when an instruction to execute SCG synchronized reconfiguration is received).

[0133] Furthermore, the terminal information notification may include information indicating that, for example, when UL data occurs, SCG (re)activation is to be performed without permission from the base station device 200 (without transmitting an SCG reactivation request in step S110, which will be described later). This makes it possible to omit some of the message transmission and reception between the base station device 200 and the terminal device 100 during SCG (re)activation.

[0134] Upon receiving the terminal information notification, the base station device 200 performs an SCG deactivation determination process (step S103). Note that the base station device 200 also performs the SCG deactivation determination process when an event occurs that requires (or may require) SCG deactivation, other than when the base station device 200 receives the terminal information notification.

[0135] The SCG deactivation determination process is a process for determining whether or not to perform SCG deactivation on the terminal device 100. In the SCG deactivation determination process, the base station device 200 determines whether or not to perform SCG deactivation, for example, using the amount of communication between the terminal device 100 and the secondary node. The base station device 200 determines to perform SCG deactivation when the amount of communication using the secondary node is small, for example, when the amount of communication between the terminal device 100 and the secondary node in a predetermined period is equal to or less than a predetermined value, or when communication between the terminal device 100 and the secondary node has not occurred for a predetermined period.

[0136] In addition, in the SCG deactivation determination process, the base station device 200 determines whether or not to perform SCG deactivation using, for example, the amount of radio resources that can be allocated to the secondary node. For example, when the amount of available radio resources of the secondary node is equal to or less than a predetermined value, the base station device 200 determines to perform SCG deactivation.

[0137] When the base station device 200 determines in the SCG deactivation determination process to perform SCG deactivation, it transmits an SCG deactivation instruction to the terminal device 100 (step S104). The SCG deactivation instruction may be, for example, an RRC message or a parameter included in the RRC message. The SCG deactivation instruction may be a parameter included in an RRC reconfiguration message, a parameter included in an RRC resumption message, a parameter included in an RRC connection reconfiguration message, or a parameter included in a message with another name. The SCG deactivation instruction may be a parameter instructing the terminal device 100 to perform SCG deactivation. Furthermore, the SCG deactivation instruction may be a parameter indicating that the SCG of the terminal device 100 is in a deactivated state. Furthermore, the SCG deactivation instruction may be a parameter such as scg-state.

[0138] The SCG deactivation instruction includes information indicating whether or not to immediately execute part or all of the SCG synchronized reconfiguration processing when the terminal device 100 is instructed to perform synchronized reconfiguration of the SCG during SCG deactivation, for example. If the instruction includes information indicating that all processing is to be performed immediately, the terminal device 100 immediately executes synchronized reconfiguration of the SCG. If the instruction includes information indicating that part or all of the processing is not to be performed immediately, the terminal device 100 executes unexecuted part of the synchronized reconfiguration processing of the SCG (suspends synchronized reconfiguration), or does not execute part or all of the synchronized reconfiguration processing of the SCG (discards part or all of the synchronized reconfiguration instruction (parameters)).

[0139] Furthermore, the SCG deactivation instruction may include information indicating that, for example, when the terminal device 100 is instructed to perform synchronized reconfiguration of the SCG during SCG deactivation, if at least a first condition is not met, the terminal device 100 immediately performs synchronized reconfiguration of the SCG if at least the first condition is not met. Also, in this case, if at least the first condition is met, the terminal device 100 executes unexecuted synchronized reconfiguration of the SCG (suspends synchronized reconfiguration), or does not execute some or all of the synchronized reconfiguration of the SCG (discards some or all of the synchronized reconfiguration instructions (parameters)) when later executing SCG (re)activation.

[0140] The first condition is, for example, that some or all of the following (Condition 1-1) to (Condition 1-4) be satisfied.

[0141] (Condition 1-1): The synchronized reconfiguration of the SCG is accompanied by a change in the master node security key (KgNB or KeNB) or a change in the AS security key generated from the master node security key.

[0142] (Condition 1-2): The synchronized reconfiguration of the SCG is accompanied by a change in the security key (S-KgNB or S-KeNB) of the secondary node or a change in the AS security key generated from the security key of the secondary node.

[0143] (Conditions 1-3): There is no radio bearer using the master key among the radio bearers associated with the SCG RLC bearer.

[0144] (Conditions 1-4): All radio bearers associated with the SCG RLC bearer must use secondary keys.

[0145] A radio bearer that uses a master key may be a radio bearer in which a parameter (keyToUse) indicating whether to use the master key or the secondary key is set to master (or primary). A radio bearer that uses a secondary key may be a radio bearer in which a parameter (keyToUse) indicating whether to use the master key or the secondary key is set to secondary.

[0146] When at least the first condition is satisfied, the terminal device 100 does not immediately execute part or all of the SCG synchronized reconfiguration process, which does not hinder communication in the MR-DC (particularly communication using the master node). As a result, the terminal device 100 does not perform unnecessary SCG (re)activation, thereby reducing power consumption.

[0147] The SCG deactivation instruction may include information instructing the terminal device 100 to immediately execute synchronized resetting of the SCG when the terminal device 100 is instructed to execute synchronized resetting of the SCG during SCG deactivation, for example. In this case, the terminal device 100 immediately executes synchronized resetting of the SCG regardless of the first condition.

[0148] Furthermore, the SCG deactivation instruction may include information to the effect that, for example, when UL data occurs, an instruction is given to execute SCG (re)activation without permission from the base station device 200. In this case, the terminal device 100 immediately executes SCG (re)activation.

[0149] When the terminal device 100 receives the SCG deactivation instruction, it performs SCG deactivation processing (step S105). The SCG deactivation processing is processing that transitions to SCG deactivation. Note that, when the terminal device 100 receives the SCG deactivation instruction, it may determine that it is necessary to perform SCG deactivation processing, and may perform SCG deactivation processing. Also, when the terminal device 100 does not receive the SCG deactivation instruction, it may determine that it is not necessary to perform SCG deactivation processing, and may not perform SCG deactivation processing.

[0150] The SCG deactivation process may include some or all of the following processes (1) to (3). (1) The SCG is considered to be deactivated. (2) Notify the lower layer that the SCG has been deactivated (3) If the terminal device 100 was in the RRC connected mode or the RRC inactive mode before receiving the RRC message including the SCG deactivation instruction, trigger an SDU discard to the PDCP entity of the SRB3 and / or re-establish the RLC entity of the SRB3.

[0151] In the process (2) above, the lower layer may be the MAC layer, the RLC layer, or the PDCP layer. Also, the process (3) above may be executed when an SRB3 is configured in the terminal device 100 and the SRB3 is not released by an RRC message including an SCG deactivation instruction.

[0152] Furthermore, if the terminal device 100 receives an RRC message including an SCG deactivation instruction during SCG deactivation, the terminal device 100 may continue the SCG deactivation state.

[0153] In addition, if the terminal device 100 receives an RRC reconfiguration message that does not include an SCG deactivation instruction, an RRC connection reconfiguration message that does not include an SCG deactivation instruction, or an RRC resume message that does not include an SCG deactivation instruction during SCG deactivation, it may determine that SCG (re)activation processing should be performed and perform the SCG (re)activation processing.

[0154] The SCG (re)activation process may include some or all of the following processes (4) and (5). (4) SCG is deemed to be (re)activated (5) If the terminal device 100 is in the process of SCG deactivation, notify the lower layer that the SCG has been (re)activated.

[0155] In the above process (5), the lower layer may be the MAC layer, the RLC layer, or the PDCP layer.

[0156] In the SCG deactivation process, the terminal device 100 stops some or all of the timers running for the SCG. Furthermore, the terminal device 100 resets some or all of the counters set in the SCG. Furthermore, the terminal device 100 resets the MAC of the SCG. Furthermore, the terminal device 100 performs a second process on at least a radio bearer that satisfies a second condition. The second condition is that the bearer is an SCG bearer, a split bearer, or a split bearer with a primary path set in the SCG. Furthermore, the radio bearer that satisfies the second condition may be, for example, some or all of the radio bearers set in the terminal device 100.

[0157] The timers running for the SCG to be stopped may include a timer for detecting a radio link failure (RLF) of the SCG. The timers running for the SCG to be stopped may also include a timer for a measurement report of the SCG. The counters set for the SCG to be reset may also include a counter for detecting a radio link failure (RLF) of the SCG.

[0158] Furthermore, "performing the second processing on radio bearers that satisfy at least the second condition" may also mean that the terminal device 100 determines whether or not each radio bearer satisfies at least the second condition, and if it determines that at least the second condition is satisfied, performs the second processing on this radio bearer.

[0159] Furthermore, "performing the second processing on radio bearers that satisfy at least the second condition" may mean that the terminal device 100 determines whether or not each radio bearer satisfies at least the second condition, and if it determines that at least the second condition is satisfied, and if it further determines that it is necessary to perform the second processing on this radio bearer, it performs the second processing on this radio bearer.

[0160] The second condition "being an SCG bearer" may mean that one or both of the parameter (moreThanOneRLC) indicating one or more RLCs and the parameter (primaryPath) indicating a primary path are not set in the radio bearer (its PDCP), and the RLC bearer of the radio bearer is in the SCG. Also, the second condition "being an SCG bearer" may mean that the RLC bearer of the radio bearer exists only in the SCG. This "RLC bearer of the radio bearer" may be an RLC bearer associated with the radio bearer.

[0161] Furthermore, the second condition, "it is a split bearer and the primary path is set in the SCG," may also mean that the primary path (or a parameter meaning the primary path) of the radio bearer (of its PDCP) is set in the SCG (or the SCG is referenced).

[0162] The second process is a process executed for some or all of the radio bearers that satisfy at least the second condition. The second process is a process when transitioning to SCG deactivation and some or all of the pre-processing. The second process includes, for example, some or all of the following processes. Hereinafter, some or all of the radio bearers that satisfy at least the second condition may be referred to as second radio bearers. Immediately transmit (until the SCG is deactivated) or completely discard any unsent data in the PDCP of the second radio bearer. If the reordering timer for the PDCP of the second radio bearer is running, it is stopped and all stored PDCP SDUs are sent to the upper layer in order after header decompression. Re-establish the RLC for the second radio bearer If the PDCP status report transmission setting is configured for the second radio bearer, the PDCP status report is sent.

[0163] The second process may be performed in accordance with the following procedure or may include the following procedure.

[0164] In the process of immediately transmitting data that has not yet been transmitted in PDCP, for example, in the case of UM DRB, PDCP SDUs that have been assigned sequence numbers but have not yet been handed over to the lower layer are regarded as PDCP SDUs that have just been received from the upper layer and are transmitted in order. In this case, there is no need to restart the discard timer.

[0165] In addition, in the process of immediately transmitting data whose transmission has not been completed in PDCP, for example, in the case of AM DRB or in the case of AM DRB in which the PDCP entity is not suspended, PDCP SDUs whose successful transmission has not been confirmed by the lower layer, and / or PDCP SDUs that have been assigned sequence numbers but have not been handed over to the lower layer, are transmitted in order.

[0166] Furthermore, in the process of immediately transmitting data whose transmission has not been completed in PDCP, for example, in the case of AM DRB for the Uu interface (the interface between the terminal device 100 and the base station device 200) where the PDCP entity is suspended, PDCP SDUs whose successful transmission has not been confirmed by the lower layer and / or PDCP SDUs that have been assigned sequence numbers but have not been handed over to the lower layer are regarded as PDCP SDUs that have just been received from the upper layer and are transmitted in order. In this case, the discard timer does not need to be restarted. The discard timer may be a timer that is used to discard the corresponding PDCP SDU when it expires.

[0167] An example of the internal operation of the terminal device 100 when performing the second process on a radio bearer that satisfies at least the second condition will be described.

[0168] For example, the RRC of the terminal device 100 sends a second notification to the PDCP of some or all of the radio bearers that are SCG bearers or split bearers. The PDCP may be replaced by a lower layer(s). The PDCP that received the second notification performs a second process if the bearer is an SCG bearer (when there is one associated RLC) or a split bearer (when there are two or more associated RLCs) and a primary path is set on the SCG side.

[0169] Furthermore, for example, the RRC of the terminal device 100 sends a second notification to the PDCP of the second radio bearer. The PDCP may be replaced by a lower layer(s). The PDCP that receives the second notification performs a second process.

[0170] The part of radio bearers that at least satisfy the second condition may be, for example, SRBs that at least satisfy the second condition, or DRBs that at least satisfy the second condition.

[0171] The second notification may be, for example, a notification instructing the discarding of PDCP data. The second notification may also be a notification instructing the immediate transmission of data that has not yet been transmitted. The second notification may also include information indicating that the SCG has been deactivated, such as "SCG deactivated" or "CG UL transmission prohibited (suspended)." The second notification may also include some or all of this information. The second notification may also be multiple messages including some of this information.

[0172] This makes it possible to suppress uplink transmissions caused by transmitting unsuccessfully transmitted UL data even when the PDCP of the SCG is re-established, for example, when the terminal device 100 receives an instruction for synchronized re-setting of the SCG but does not execute the instruction immediately but executes it later. That is, the terminal device 100 can suppress unnecessary SCG (re)activation and reduce power consumption.

[0173] Furthermore, in the SCG deactivation process, the RRC of the terminal device 100 transmits second information to the SDAP associated with the DRB of the second radio bearer. The second information is information indicating that uplink transmission is not possible for the DRB, such as that UL transmission of the DRB is prohibited (or stopped) or that the cell group associated with the DRB is being deactivated.

[0174] The second information may also be transmitted to the SDAP together with some or all of the following information: The second information may also be some or all of the following information: -DRB identifier of the DRB QoS flow identifier associated with the DRB

[0175] In addition, "sending the second information to the SDAP associated with the DRB among the second radio bearers" may also mean that the terminal device 100 determines for each DRB whether at least the second condition is satisfied, and if it determines that at least the second condition is satisfied, sends the second information to the SDAP associated with this DRB.

[0176] Furthermore, "sending the second information to an SDAP associated with a DRB among the second radio bearers" may also mean that the terminal device 100 determines for each DRB whether at least the second condition is met, and if it determines that at least the second condition is met and that it is necessary to send the second information to the SDAP associated with this DRB, it sends the second information to the SDAP associated with this DRB.

[0177] Note that "transmitting the second information to the SDAP associated with the DRB of the second radio bearer" may be rephrased as "transmitting the second information to the SDAP."

[0178] The transmission process of the second information may be executed when a DRB that satisfies at least the second condition is associated with an SDAP (if an SDAP entity associated with this DRB is configured). The terminal device 100 may determine whether each DRB is associated with an SDAP, and if it is determined that the DRB is associated with an SDAP, determine whether this DRB satisfies at least the second condition. The terminal device 100 may also determine whether each DRB satisfies at least the second condition, and if it is determined that the DRB satisfies at least the second condition, determine whether this DRB is associated with an SDAP.

[0179] [RRC reconfiguration message reception processing during SCG deactivation] FIG. 13 is a sequence diagram showing an RRC message transmission / reception operation of the terminal device 100 during SCG deactivation.

[0180] The base station device 200 transmits an RRC reconfiguration message (first message) to the terminal device 100 during SCG deactivation (step S106). Note that transmitting an RRC reconfiguration message to the terminal device 100 during SCG deactivation may mean transmitting to the terminal device 100 an RRC reconfiguration message including a parameter (SCG deactivation instruction) instructing that the SCG be put into a deactivation state. When transmitting the RRC reconfiguration message including the SCG deactivation instruction, the state of the SCG of the terminal device 100 may be in activation or in deactivation. Note that the RRC reconfiguration message is an RRC message related to reconfiguration of an RRC connection transmitted from the base station device 200 to the terminal device 100, and performs establishment, configuration, modification, and release of radio bearers, cell groups, measurement information, etc., as well as synchronized reconfiguration. The RRC reconfiguration message may be, for example, the RRC message RRCReconfiguration, or a message with another name.

[0181] When the base station apparatus 200 determines that it is necessary to change the setting of the terminal apparatus 100 (change the setting in the RRC connected mode), the base station apparatus 200 generates an RRC reconfiguration message and transmits it to the terminal apparatus 100.

[0182] The base station device 200 determines that a change in the settings of the terminal device 100 is necessary, for example, when an MGC handover is necessary. The base station device 200 also determines that a change in the settings of the terminal device 100 is necessary, for example, when a security key change is necessary. The base station device 200 determines that a change in the settings of the terminal device 100 is necessary if a PDCP related to the security key that needs to be changed (using a key generated from the security key) needs to be re-established. The base station device 200 also determines that a change in the settings of the terminal device 100 is necessary, for example, when a change in the QoS flow to DRB mapping rule (a rule indicating the correspondence (map) between QoS flows and DRBs) needs to be made.

[0183] The RRC reconfiguration message includes, for example, the following information: -Information to instruct the SCG to perform synchronized reconfiguration If the information instructing to perform synchronized reconfiguration of the SCG is included, information instructing to immediately perform synchronized reconfiguration of the SCG if at least the first condition is not met If the information includes information instructing to perform synchronized reconfiguration of the SCG, and if at least the first condition is met, information instructing to perform synchronized reconfiguration of the SCG at the time of SCG (re)activation If the information includes instructions to perform synchronized reconfiguration of the SCG, if SCG deactivation is in progress, information to immediately perform synchronized reconfiguration of the SCG If it includes information instructing to perform synchronized reconfiguration of the SCG, information instructing to perform synchronized reconfiguration of the SCG at the time of SCG (re)activation

[0184] The first condition is the first condition used in step S103. That is, the first condition is, for example, that some or all of the above (Condition 1-1) to (Condition 1-4) are satisfied.

[0185] In addition, if the base station device 200 determines that it does not want the terminal device 100 to immediately perform synchronized reconfiguration of the SCG, it does not have to include synchronized reconfiguration parameters in the parameter (for example, the name secondaryCellGroup) that indicates SCG configuration in the RRC reconfiguration message (it does not have to request synchronized reconfiguration of the SCG).

[0186] Furthermore, when the terminal device 100 is undergoing SCG deactivation, the base station device 200 may determine that it is optional (not essential) to include reconfiguration parameters with SCG synchronization in the RRC reconfiguration message to the terminal device 100. For example, if it is necessary to update the security key of the secondary node, but the terminal device 100 is undergoing SCG deactivation and there is no MN terminated RLC bearer (associated with the master key) on the SCG side, the base station device 200 does not include reconfiguration parameters with SCG synchronization in the RRC reconfiguration message.

[0187] Furthermore, when at least the third condition is satisfied and the terminal device 100 is not undergoing SCG deactivation, the base station device 200 may determine that it is essential to include SCG synchronization reconfiguration parameters in the RRC reconfiguration message to the terminal device 100, and may always include the SCG synchronization reconfiguration parameters. Furthermore, even when at least the third condition is satisfied, when the terminal device 100 is undergoing SCG deactivation, the base station device 200 may determine that it is optional (not essential) to include SCG synchronization reconfiguration parameters in the RRC reconfiguration message to the terminal device 100, and may not include the SCG synchronization reconfiguration parameters.

[0188] The third condition may be, for example, that the AS security key generated from the security key of the secondary node in the NR-DC (S-KgNB or S-KeNB) is changed, or that one or more radio bearers using the secondary key are configured in the terminal device 100 and that the radio bearers are not released even when processing is performed upon receiving an RRC reconfiguration request.

[0189] Furthermore, the third condition may be, for example, that the base station device 200 executes MN handover in (NG)EN-DC. Furthermore, the third condition may be, for example, that the base station device 200 performs SCG (re)activation.

[0190] In addition, if the RRC reconfiguration message to the terminal device 100 includes a change to the AS security key generated from the master node security key (KgNB or KeNB) and does not include a reconfiguration parameter with SCG synchronization, the base station device 200 may determine to release all existing SCG RLC bearers associated with radio bearers that use the master key if the terminal device 100 is not in the process of SCG deactivation.

[0191] In addition, if the RRC reconfiguration message to the terminal device 100 includes a change to the AS security key generated from the master node security key (KgNB or KeNB) and does not include a reconfiguration parameter with SCG synchronization, the base station device 200 may determine that it is not necessary to release all existing SCG RLC bearers associated with radio bearers that use the master key if the terminal device 100 is undergoing SCG deactivation.

[0192] Furthermore, the base station device 200 may include, in the RRC reconfiguration message, a parameter instructing to perform synchronized reconfiguration of the SCG and a parameter instructing to perform SCG deactivation.

[0193] A radio bearer that uses a master key may be a radio bearer in which a parameter (keyToUse) indicating whether to use the master key or the secondary key is set to master (or primary). A radio bearer that uses a secondary key may be a radio bearer in which a parameter (keyToUse) indicating whether to use the master key or the secondary key is set to secondary.

[0194] Upon receiving the RRC reconfiguration message, the terminal device 100 performs an RRC message reception process during SCG deactivation (step S107). In the RRC message reception process during SCG deactivation, the terminal device 100 performs processing in accordance with information (parameters) included in the RRC reconfiguration message.

[0195] The RRC reconfiguration message includes, for example, the following parameters: - Synchronous reconfiguration parameter (indicates that synchronized reconfiguration is to be performed) Parameter to instruct PDCP re-establishment (indicates that PDCP re-establishment is to be executed) Parameter indicating the setting of the QoS flow to DRB mapping rule (indicates that the QoS flow to DRB mapping rule is to be reconfigured)

[0196] The processing when each parameter is included will be described below.

[0197] -1. When synchronization reset parameters are included- When the received RRC reconfiguration message includes a synchronization-attached reconfiguration parameter, if a predetermined condition is satisfied, the terminal device 100 resumes uplink communication of the suspended SCG-side radio bearer if the SCG-side radio bearer is suspended. The predetermined condition is, for example, that SCG deactivation is not in progress. Note that "if a predetermined condition is satisfied" may be rephrased as "determining whether or not the predetermined condition is satisfied, and determining that the predetermined condition is satisfied."

[0198] Furthermore, the predetermined condition may be, for example, any one of the following (Condition 2-1) to (Condition 2-3).

[0199] (Condition 2-1): Meet some or all of the following conditions: The CellGroupConfig procedure is initiated by the MCG configuration parameters and is not in the process of SCG deactivation. The procedure was initiated by the SCG configuration parameters

[0200] (Condition 2-2): Meet some or all of the following conditions: The CellGroupConfig procedure is initiated by the MCG configuration parameters and is not in the process of SCG deactivation. The procedure is initiated by SCG configuration parameters, is in the process of SCG deactivation, and includes a parameter indicating immediate synchronized reconfiguration of the SCG (or does not include a parameter indicating no immediate synchronized reconfiguration of the SCG). The procedure is initiated by SCG setting parameters and is not in the process of SCG deactivation.

[0201] (Conditions 2-3): Meet some or all of the following conditions: -SCG is not currently deactivated -SCG deactivation is in progress and a parameter indicating that SCG will be immediately reconfigured with synchronization is included (or a parameter indicating that SCG will not be immediately reconfigured with synchronization is not included).

[0202] When SCG deactivation is in progress, the terminal device 100 may determine that the SCG-side radio bearer is not in a suspended state but in another state (for example, the SCG is in a deactivated state or uplink transmission is prohibited). When the synchronization-included reconfiguration parameter is included, the terminal device 100 may resume uplink communication of the suspended SCG-side radio bearer regardless of whether SCG deactivation is in progress or not.

[0203] Furthermore, when the received RRC reconfiguration message includes reconfiguration parameters with SCG synchronization, the terminal device 100 may perform the following process. The terminal device 100 may immediately perform the SCG synchronization reset process.

[0204] Furthermore, the terminal device 100 may not immediately execute some or all of the processes of the synchronized reconfiguration of the SCG, and may execute the processes that are not immediately executed at the time of SCG (re)activation. Processes that are immediately executed include, for example, a MAC reset on the SCG side, and applying the identifier of the new terminal device 100 as the C-RNTI of the cell group. Processes that are executed at the time of SCG (re)activation include, for example, a random access process on the SCG side (which may include a process of configuring lower layers in accordance with a parameter (SpCellConfigCommon) that means the received common SpCell configuration), starting a timer for detecting a synchronized reconfiguration failure, and the like.

[0205] The terminal device 100 may determine whether to immediately perform the SCG synchronized reconfiguration process according to the SCG deactivation instruction in step S104 or a parameter (parameter indicating whether to immediately perform the SCG synchronized reconfiguration) included in the RRC reconfiguration message in step S106. For example, the terminal device 100 may immediately perform the SCG synchronized reconfiguration process if at least the first condition is not met, and may perform the SCG synchronized reconfiguration process at the time of SCG (re)activation if the first condition is met. Furthermore, the terminal device 100 may return to the SCG deactivation process again after performing the above-described process.

[0206] The first condition is the first condition used in step S103. That is, the first condition is, for example, that some or all of the above (Condition 1-1) to (Condition 1-4) are satisfied.

[0207] -2. When a parameter instructing PDCP re-establishment is included- If the received RRC reconfiguration message includes a parameter instructing PDCP re-establishment, the terminal device 100 immediately performs PDCP re-establishment, for example. In this case, if there is data whose transmission has not been completed in the PDCP of at least some or all of the radio bearers that satisfy the second condition, the terminal device 100 may transmit the data after the SCG is (re)activated.

[0208] Furthermore, the terminal device 100 may perform PDCP re-establishment of some or all of the radio bearers that satisfy at least the second condition after the SCG is (re)activated. In this case, even if the PDCP re-establishment is performed after the SCG (re)activation, the PDCP that receives a PDCP SDU from an upper layer does not perform processing corresponding to the PDCP SDU.

[0209] The second condition may be the second condition used in step S105, that is, that it is an SCG bearer, or that it is a split bearer and a primary path is set in the SCG.

[0210] In the process of transmitting data that has not yet been transmitted in PDCP, for example, in the case of UM DRB, the terminal device 100 regards PDCP SDUs that have been assigned sequence numbers but have not yet been handed over to a lower layer as PDCP SDUs that have just been received from a higher layer, and transmits them in order. In this case, there is no need to restart the discard timer.

[0211] Furthermore, in the process of transmitting data whose transmission has not been completed in PDCP, for example, in the case of AM DRB or in the case of AM DRB in which the PDCP entity is not suspended, the terminal device 100 transmits, in order, PDCP SDUs whose successful transmission has not been confirmed by the lower layer, and PDCP SDUs that have been assigned sequence numbers but have not been handed over to the lower layer.

[0212] Furthermore, in the process of transmitting data that has not been transmitted in PDCP, for example, in the case of AM DRB for a Uu interface where the PDCP entity is suspended, the terminal device 100 regards PDCP SDUs for which successful transmission has not been confirmed by a lower layer and PDCP SDUs that have been assigned sequence numbers but have not been passed to a lower layer as PDCP SDUs that have just been received from a higher layer, and transmits them in order. In this case, there is no need to restart the discard timer.

[0213] The discard timer may be a timer used to discard the corresponding PDCP SDU when it expires.

[0214] The base station device 200 may include, in the RRC reconfiguration message of step S106, a parameter indicating that the PDCP re-establishment process for some or all of the radio bearers that satisfy at least the second condition should be performed immediately (or should be performed after the SCG is (re)activated).The terminal device 100 may determine from the parameter whether the PDCP re-establishment process for some or all of the radio bearers that satisfy at least the second condition should be performed immediately or after the SCG is (re)activated.

[0215] -3. When a parameter indicating the setting of the QoS flow to DRB mapping rule is included: When the received RRC reconfiguration message includes a parameter (mappedQoS-FlowToAdd) indicating the setting of a QoS flow to DRB mapping rule, the terminal device 100 performs the following process. Note that the QoS flow to DRB mapping rule indicates, for example, the correspondence between the QoS flow and the DRB.

[0216] The terminal device 100 performs end marker processing when a predetermined condition is met. End marker processing is a process of constructing an end marker control PDU, mapping it to the DRB before the change, and transmitting it to a lower layer. Note that "when a predetermined condition is met" can also be rephrased as "when it is determined whether or not the predetermined condition is met and it is determined that the condition is met."

[0217] Here, for example, it is assumed that the mappedQoS-FlowToAdd included in the received RRC reconfiguration message is a parameter for the first QoS flow.

[0218] When some or all of the following (Condition 3-1) to (Condition 3-3) are satisfied, the terminal device 100 performs end marker processing when the DRB of the QoS flow to DRB mapping rule stored for the first QoS flow (i.e., the DRB corresponding to the already stored first QoS flow) is a DRB that does not correspond to the second information received from the RRC of the terminal device 100 in step S105. Furthermore, even when some or all of the following (Condition 3-1) to (Condition 3-3) are satisfied, the terminal device 100 does not perform end marker processing when the DRB of the QoS flow to DRB mapping rule stored for the first QoS flow is a DRB that corresponds to the second information received from the RRC of the terminal device 100 in step S105.

[0219] (Condition 3-1): In step S105, the second information is notified to an SDAP to which at least a data radio bearer that satisfies the second condition is associated.

[0220] (Condition 3-2): The QoS flow to DRB mapping rule stored for the first QoS flow is different from the QoS flow to DRB mapping rule set (by the mappedQoS-FlowToAdd included in the received RRC reconfiguration message). In other words, the DRB associated with the first QoS flow by the newly received QoS flow to DRB mapping rule has changed from the DRB associated with the stored (already received) QoS flow to DRB mapping rule.

[0221] (Condition 3-3): The uplink SDAP header is set in the DRB of the stored QoS flow to DRB mapping rule.

[0222] In addition, if an SDAP entity has already been established, and a QoS flow to DRB mapping rule for the first QoS flow does not exist (is not stored), and a default DRB has been set, the terminal device 100 may perform some or all of the following processing.

[0223] (Process 1) If the default DRB is a DRB that does not correspond to the second information received from the RRC of the terminal device 100 in step S105, an end marker control PDU is constructed, mapped to the default DRB, and transmitted to a lower layer.

[0224] (Process 2) If the default DRB is a DRB corresponding to the second information received from the RRC of the terminal device 100 in step S105, construction of an end marker control PDU, mapping of the constructed end marker control PDU to the default DRB, and transmission to a lower layer are not performed in part or in whole.

[0225] The QoS flow to DRB mapping rule may be a QoS flow to DRB mapping rule for the uplink (UL QoS flow to DRB mapping rule).

[0226] Furthermore, in step S105, if the second notification has been made from the RRC of the terminal device 100 to the PDCP (if the PDCP recognizes that the PDCP is a PDCP of a radio bearer that at least satisfies the second condition), the terminal device 100 creates an end marker control PDU (SDAP Control PDU) and transmits it to the PDCP. Upon receiving the SDAP Control PDU, the PDCP of the terminal device 100 discards the received SDAP Control PDU. Alternatively, the PDCP of the terminal device 100 may discard the SDAP Control PDU if the bearer is a split bearer and the primary path is in the SCG.

[0227] Note that the implementation of the base station device 200 may prevent the terminal device 100 from transmitting an end marker control PDU to the SCG during SCG deactivation. For example, the base station device 200 does not include mappedQoS-FlowToAdd in an RRC reconfiguration message that the terminal device 100 transmits to the terminal device 100 during SCG deactivation. Also, for example, when the terminal device 100 includes mappedQoS-FlowToAdd in an RRC reconfiguration message that the terminal device 100 transmits to the terminal device 100 during SCG deactivation, the base station device 200 performs configuration so that the terminal device 100 does not transmit an end marker control PDU to the SCG side.

[0228] Furthermore, when the terminal device 100 determines that it is unable to perform processing in accordance with the RRC reconfiguration message received from the base station device 200, it may initiate an RRC connection re-establishment procedure or a procedure related to an SCG radio link failure (RLF) with respect to the base station device 200. For example, when a synchronization-related reconfiguration parameter is required in the RRC reconfiguration message received from the base station device 200 but the synchronization-related reconfiguration parameter is not included, the terminal device 100 determines that it is unable to perform processing in accordance with the received RRC reconfiguration message. Furthermore, when an end marker transmission to the SCG occurs due to the RRC reconfiguration message received from the base station device 200 even though SCG deactivation is in progress, the terminal device 100 determines that it is unable to perform processing in accordance with the received RRC reconfiguration message.

[0229] [UL data arrival during SCG deactivation] 14 is a sequence diagram showing an SCG reactivation operation during SCG deactivation. While the terminal device 100 is performing SCG deactivation, UL data may arrive (step S108). The arrival of UL data indicates that data to be transmitted to the base station device 200 has occurred, and may be, for example, the arrival (transmission) of a PDCP SDU to the PDCP, or the arrival (transmission) of a MAC SDU to the MAC on the SCG side.

[0230] When the UL data arrives, the terminal device 100 performs UL data transmission processing during SCG deactivation (step S109). The UL data transmission processing during SCG deactivation is a processing that determines whether or not to immediately transmit the UL data to the master node or secondary node, and transmits the UL data at an appropriate timing. Below, the UL data transmission processing during SCG deactivation will be explained separately for the case where a PDCP SDU arrives at the PDCP and the case where a MAC SDU arrives at the MAC on the SCG side.

[0231] -1. When a PDCP SDU arrives at the PDCP- When a second notification is made from the RRC of the terminal device 100 to the PDCP (when the PDCP recognizes that the radio bearer satisfies at least the second condition), the PDCP of the terminal device 100 that detects the arrival of the PDCP SDU notifies the RRC of the terminal device 100 that UL data has occurred. Here, when a split bearer is established and there is a primary path in the SCG, the terminal device 100 may make a notification to the RRC of the terminal device 100 when it receives a PDCP SDU from a higher layer. On the other hand, when a split bearer is established and there is a primary path in the MCG, the terminal device 100 may make a notification to the RRC of the terminal device 100 when the amount of transmission data has exceeded or is about to exceed a predetermined threshold.

[0232] The RRC of the terminal device 100, which has received notification from the PDCP of the terminal device 100 that UL data has been generated, transmits an SCG reactivation request to the base station device 200 (step S110). The SCG reactivation request may be a message requesting SCG (re)activation to be performed, or a message including parameters requesting SCG (re)activation to be performed.

[0233] The SCG reactivation request is, for example, an RRC message. The SCG reactivation request may be, for example, an RRC message called "SCG reactivation request," or may be a message with another name.

[0234] -2.When MAC SDU arrives at MAC on the SCG side- The RRC processing of the terminal device 100 is the same as when the PDCP SDU described above arrives at the PDCP. When the MAC of the terminal device 100 detects the arrival of the MAC SDU, it notifies the RRC of the terminal device 100 that UL data has been generated. Furthermore, the MAC of the terminal device 100 may perform SCG (re)activation and prepare for transmitting UL data (for example, executing a random access procedure with respect to a secondary node). If there is synchronized reconfiguration of the SCG that was not immediately performed in step S107 or the like, the terminal device 100 may perform synchronized reconfiguration of the SCG in advance. Furthermore, the MAC of the terminal device 100 may perform all processing related to SCG (re)activation after receiving an SCG reactivation instruction from the base station device 200.

[0235] Furthermore, the MAC of the terminal device 100 may perform SCG (re)activation and start transmitting UL data without notifying the RRC of the terminal device 100 that UL data has been generated. Before starting transmission of UL data, the terminal device 100 may perform synchronized reconfiguration of the SCG if there is synchronized reconfiguration of the SCG that was not immediately performed in step S107.

[0236] For example, if the SCG deactivation instruction received in step S104 includes an instruction regarding processing when UL data occurs during SCG deactivation (for example, whether or not SCG (re)activation can be performed without sending an SCG reactivation request), the terminal device 100 may follow this instruction.

[0237] The base station device 200 determines whether or not SCG (re)activation is necessary for the terminal device 100. The base station device 200 determines that SCG (re)activation of the terminal device 100 is necessary when, for example, some or all of the following (Condition 4-1) to (Condition 4-3) are met.

[0238] (Condition 4-1): An SCG reactivation request is received from the terminal device 100.

[0239] (Condition 4-2): DL data to be transmitted to the terminal device 100 via the SCG is generated.

[0240] (Condition 4-3): The remaining amount of radio resources of the secondary node is sufficient (above a predetermined threshold).

[0241] Note that the base station device 200 may determine whether SCG reactivation of the terminal device 100 is necessary at any time as long as the terminal device 100 is undergoing SCG deactivation.

[0242] When determining that SCG (re)activation is necessary, the base station device 200 transmits an SCG reactivation instruction to the terminal device 100, instructing (allowing) the execution of SCG (re)activation (step S111). The SCG reactivation instruction is, for example, an RRC message. The SCG reactivation instruction may also be, for example, an RRC reconfiguration message or a message with another name. The SCG reactivation instruction may also be an RRC reconfiguration message that does not include an SCG deactivation instruction.

[0243] Upon receiving the SCG reactivation instruction, the terminal device 100 performs an SCG reactivation process (step S112). The SCG reactivation process is a process in which the terminal device 100 (re)activates the SCG.

[0244] Note that the RRC of the terminal device 100 may transmit a third notification to the PDCP that transmitted the second notification in step S105. The third notification may be a notification indicating that SCG (re)activation will be performed or a notification indicating that SCG deactivation will be canceled, and may be, for example, a notification indicating that "SCG has been (re)activated" or "uplink transmission of SCG has been permitted (resumed)." Upon receiving the third notification, the PDCP of the terminal device 100 resumes uplink transmission of the SCG.

[0245] [RRC message processing during radio bearer suspension on the SCG side] FIG. 16 is a sequence diagram showing an RRC message transmission / reception operation when at least the radio bearer on the SCG side of the terminal device 100 is in a paused (suspended) state (the radio bearer is suspended). The radio bearer on at least the SCG side of the terminal device 100 being suspended may refer to, for example, the case where the terminal device 100 is in an RRC inactive mode. The radio bearer on at least the SCG side of the terminal device 100 being suspended may refer to, for example, a state where the terminal device 100 detects an SCG failure and SCG transmission of the radio bearer is suspended. The radio bearer being suspended may refer to, for example, some or all of the following states: a state where no transmission is performed on the radio bearer, a state where no reception is performed on the radio bearer, and a state where data processing is not performed in some or all entities set in the radio bearer. The SCG transmission of the radio bearer being suspended may refer to, for example, a state including a state where no transmission is performed on the radio bearer associated with the SCG.

[0246] Furthermore, the terminal device 100 in which at least the radio bearer on the SCG side is suspended may be undergoing SCG deactivation. Furthermore, the terminal device 100 in which at least the radio bearer on the SCG side is suspended may be undergoing SCG (re)activation.

[0247] Furthermore, the RRC message may be an RRC resumption message when the terminal device 100 is in an RRC inactive mode. In this case, the terminal device 100 may transmit an RRC resumption request message to the base station device 200 before receiving an RRC message from the base station device 200. Furthermore, the RRC message may be an RRC reconfiguration message when the terminal device 100 is in an RRC connected mode. Note that the RRC resumption message may include an RRC reconfiguration message, and this RRC reconfiguration message may include an SCG configuration.

[0248] The base station device 200 transmits an RRC message to at least the terminal device 100 for which the SCG-side radio bearer is suspended (step S113). When the base station device 200 determines that the terminal device 100 will resume transmission of the suspended SCG-side radio bearer, the base station device 200 includes the tenth parameter in the RRC message but does not include the eleventh parameter, and transmits the RRC message to the terminal device 100. When the base station device 200 determines that the terminal device 100 will not resume transmission of the suspended SCG-side radio bearer, the base station device 200 includes the tenth parameter and the eleventh parameter in the RRC message and transmits the RRC message to the terminal device 100.

[0249] The above phrase "resumes transmission of the radio bearer on the suspended SCG side" may be rephrased as "resumes transmission of the radio bearer on the suspended SCG side and performs random access to the SCG." Furthermore, the above phrase "does not resume transmission of the radio bearer on the suspended SCG side" may be rephrased as "does not resume transmission of the radio bearer on the suspended SCG side and does not perform random access to the SCG."

[0250] The terminal device 100 in which at least the SCG-side radio bearer is suspended performs processing in accordance with the RRC message received from the base station device 200 (step S114). When the RRC message received from the base station device 200 includes the tenth parameter but not the eleventh parameter, the terminal device 100 in which at least the SCG-side radio bearer is suspended determines to resume transmission of the suspended SCG-side radio bearer and resumes transmission of the suspended SCG-side radio bearer. Furthermore, when the RRC message received from the base station device 200 includes the tenth parameter and the eleventh parameter, the terminal device 100 in which at least the SCG-side radio bearer is suspended determines not to resume transmission of the suspended SCG-side radio bearer and does not resume transmission of the suspended SCG-side radio bearer.

[0251] Note that the above phrase "when the RRC message received from base station device 200 includes the tenth parameter but does not include the eleventh parameter" may be rephrased as "when the RRC message received from base station device 200 includes the tenth parameter and the SCG has not been deactivated" or "when the RRC message received from base station device 200 includes the tenth parameter and the SCG has been (re)activated". Furthermore, the above phrase "when the RRC message received from base station device 200 includes the tenth parameter and the eleventh parameter" may be rephrased as "when the RRC message received from base station device 200 includes the tenth parameter and the SCG has been deactivated" or "when the RRC message received from base station device 200 includes the tenth parameter and the SCG has not been (re)activated".

[0252] The above phrase "resumes transmission of the radio bearer on the suspended SCG side" may be rephrased as "resumes transmission of the radio bearer on the suspended SCG side, and performs random access to the SCG." The above phrase "does not resume transmission of the radio bearer on the suspended SCG side" may be rephrased as "does not resume transmission of the radio bearer on the suspended SCG side, and does not perform random access to the SCG."

[0253] The above-mentioned tenth parameter may be a synchronization reset parameter. The above-mentioned tenth parameter may be a synchronization reset parameter for SCG. The above-mentioned eleventh parameter may be an SCG deactivation instruction. The SCG deactivation instruction may be a parameter that instructs the terminal device 100 to perform SCG deactivation. The SCG deactivation instruction may be a parameter that indicates that the SCG of the terminal device 100 is in a deactivated state. The SCG deactivation instruction may be a parameter called scg-state.

[0254] The above-mentioned process of "resume transmission of the radio bearer on the suspended SCG side" or the process of "not resume transmission of the radio bearer on the suspended SCG side" may be performed after the synchronous reconfiguration process. The above-mentioned process of "resume transmission of the radio bearer on the suspended SCG side" or the process of "not resume transmission of the radio bearer on the suspended SCG side" may be performed after the process of resuming the suspended radio bearer or simultaneously with the process of resuming the suspended radio bearer. The process of resuming the suspended radio bearer may be, for example, a process of resuming data processing in each entity configured for the radio bearer. The process of resuming the suspended radio bearer may not be performed for some of the suspended radio bearers. Some of the suspended radio bearers may be, for example, SRBs for the source cell group.

[0255] In addition, the above-mentioned process of "not resuming transmission of the suspended radio bearer on the SCG side" may be performed after the SCG deactivation process.

[0256] In addition, the radio bearer on the SCG side may be a radio bearer associated with the SCG.

[0257] Furthermore, the same processing as that for the SCG-side radio bearer described above may be performed for the BH (Backhaul) RLC channel for the IAB (Integrated Access and Backhaul)-MT (Mobile Termination) on the SCG side. That is, if it is determined that "transmission of the suspended SCG-side radio bearer is to be resumed," SCG transmission for the BH RLC channel for the suspended IAB-MT may be resumed. Also, if it is determined that "transmission of the suspended SCG-side radio bearer is not to be resumed," SCG transmission for the BH RLC channel for the suspended IAB-MT does not need to be resumed.

[0258] This makes it possible to prevent data transmission during SCG deactivation, thereby reducing power consumption of the terminal device.

[0259] Note that the terminal device 100 in which at least the radio bearer on the SCG side is suspended may perform the following process instead of the process of determining whether or not to resume transmission of the suspended radio bearer on the SCG side. If the RRC message contains a synchronized reconfiguration, the transmission of the suspended radio bearer on the SCG side is resumed regardless of whether the RRC message contains an SCG deactivation instruction. After the process of resuming transmission of the suspended radio bearer on the SCG side described above, perform SCG deactivation process and / or synchronized reconfiguration process.

[0260] [RRC message processing for controlling uplink transmission of control PDUs] When the terminal device 100 receives an RRC message including DRB configuration parameters, if the DRB configuration parameters include a parameter instructing PDCP re-establishment or a parameter instructing PDCP data recovery, and if PDCP status report transmission is configured for the DRB corresponding to the DRB configuration, the PDCP entity in the DRB corresponding to the DRB configuration of the terminal device 100 (a DRB having the same DRB identifier as the DRB identifier included in the DRB configuration parameters) transmits a PDCP status report in the uplink direction. If the DRB is an SCG bearer, or if it is a split bearer and the primary path is configured for the SCG, and if the above-mentioned RRC message includes an SCG deactivation instruction, the terminal device 100 needs to temporarily set the SCG to a deactivated state and then perform a process of setting the SCG to a (re)activated state in order to transmit the PDCP status report, which consumes power. To avoid this problem, the base station device 200 may prevent the terminal device 100 from transmitting control PDUs such as PDCP status reports and / or data PDUs when the terminal device 100 is undergoing SCG deactivation. Also, to avoid this problem, the terminal device 100 may prevent the terminal device 100 from transmitting control PDUs such as PDCP status reports and / or data PDUs when the terminal device 100 is undergoing SCG deactivation.

[0261] An example of the process will be described with reference to Fig. 17. Fig. 17 is a sequence diagram showing an RRC message transmission / reception operation for controlling uplink transmission of a control PDU.

[0262] The base station device 200 performs processing to generate an RRC message to be transmitted to the terminal device 100 (step S115). The above-mentioned RRC message may be, for example, an RRC reconfiguration message, an RRC resumption message, an RRC connection reconfiguration message, or another message.

[0263] A first example of the processing in step S115 will be described. When the base station device 200 sends an RRC message to the terminal device 100 to put the SCG of the terminal device 100 into the deactivation state and to instruct PDCP re-establishment and / or PDCP data recovery to the first DRB established in the terminal device 100, the base station device 200 determines to release the PDCP status report transmission setting set in the first DRB. The base station device 200 may then generate an RRC message indicating that the PDCP status report transmission setting set in the first DRB will be released. Releasing the PDCP status report transmission setting set in the first DRB may mean including DRB configuration parameters for the first DRB in the RRC message, further including PDCP configuration parameters in the DRB configuration parameters, and not including a parameter (statusReportRequired) for setting PDCP status report transmission in the PDCP configuration parameters. That is, the RRC message may include DRB configuration parameters for the above-mentioned first DRB, and the DRB configuration parameters may further include PDCP configuration parameters that do not include a parameter for setting PDCP status report transmission. Furthermore, the process of releasing the setting of PDCP status report transmission for the above-mentioned first DRB may be performed when PDCP status report transmission is set for the above-mentioned first DRB. Note that a first example of the process in step S115 may be performed when transmitting an RRC reconfiguration message for the first time or transmitting an RRC resumption message for the first time after the SCG of the terminal device 100 changes from the (re)activation state to the deactivation state.

[0264] A second example of the processing in step S115 will be described. When the base station device 200 transmits an RRC message to the terminal device 100 to instruct PDCP re-establishment and / or PDCP data recovery for the first DRB established in the terminal device 100, the base station device 200 may determine to place the SCG of the terminal device 100 in a (re)activation state, and may generate an RRC message indicating that the SCG of the terminal device 100 is placed in a (re)activation state.

[0265] A third example of the processing in step S115 will be described. When the base station device 200 puts the SCG of the terminal device 100 into the deactivation state by transmitting an RRC message to the terminal device 100, the base station device 200 may determine that it will not issue a PDCP re-establishment and / or PDCP data recovery instruction to the first DRB established in the terminal device 100, and may generate an RRC message indicating that it will not issue a PDCP re-establishment and / or PDCP data recovery instruction to the first DRB.

[0266] In the above examples of the processes, "setting the SCG of the terminal device 100 to a deactivation state" may mean including an SCG deactivation instruction in an RRC message. Furthermore, "setting the SCG of the terminal device 100 to a (re)activation state" may mean not including an SCG deactivation instruction in an RRC message. Furthermore, "instructing the first DRB configured in the terminal device 100 to perform PDCP re-establishment" may mean including, in an RRC message, DRB configuration parameters for the first DRB configured in the terminal device 100 (DRB configuration parameters including the same DRB identifier as the first DRB) and including, in this DRB configuration, a parameter (reestablishPDCP) that instructs PDCP re-establishment. Furthermore, "instructing the first DRB configured in the terminal device 100 to perform PDCP data recovery" may mean including, in an RRC message, DRB configuration parameters for the first DRB configured in the terminal device 100 and including, in this DRB configuration, a parameter (recoverPDCP) that instructs PDCP data recovery. Furthermore, "not instructing PDCP data recovery to the first DRB established in the terminal device 100" may mean not including DRB setting parameters for the first DRB established in the terminal device 100 in the RRC message, or including DRB setting parameters for the first DRB established in the terminal device 100 in the RRC message, but not including a parameter (recoverPDCP) instructing PDCP data recovery in this DRB setting. Note that the first DRB may be a DRB associated with the SCG of the terminal device 100. Also, the DRB associated with the SCG may be a DRB that is an SCG bearer. Also, the DRB associated with the SCG may be a DRB that is a split bearer, or a DRB that is a split bearer and whose primary path is set to the SCG. Also, the first DRB may be an AM DRB.

[0267] The base station device 200 transmits the RRC message generated in step S115 to the terminal device 100 (step S116). The terminal device 100 performs processing in accordance with the RRC message received from the base station device 200 (step S117).

[0268] A first example of the processing in step S117 will be described. If the RRC message received from the base station device 200 includes an SCG deactivation instruction and the DRB configuration for the first DRB established in the terminal device 100 includes a parameter instructing PDCP re-establishment and / or a parameter instructing PDCP data recovery, the terminal device 100 determines not to transmit a PDCP status report even if PDCP status report transmission is configured for the first DRB, and does not transmit the PDCP status report.

[0269] A second example of the processing in step S117 will be described. If the RRC message received from the base station device 200 includes an SCG deactivation instruction and the DRB configuration for the first DRB established in the terminal device 100 includes a parameter instructing PDCP re-establishment and / or a parameter instructing PDCP data recovery, the terminal device 100 determines that the PDCP status report should be transmitted after SCG (re)activation, even if PDCP status report transmission is configured for the first DRB, and transmits the PDCP status report after SCG (re)activation.

[0270] In the processing in step S117, the first DRB may be a DRB associated with the SCG of the terminal device 100. Also, the DRB associated with the SCG may be a DRB that is an SCG bearer. Also, the DRB associated with the SCG may be a DRB that is a split bearer, or a DRB that is a split bearer and whose primary path is set to the SCG. Also, the first DRB may be an AM DRB.

[0271] (Embodiment 2) Consider the case where the terminal device 100 is undergoing SCG deactivation, the SDAP entity of the terminal device 100 sets a Reflective QoS flow to DRB mapping Indication (RDI) to “1”, a downlink SDAP data PDU is received, and the received downlink SDAP data PDU includes a QoS flow identifier (QFI) for a second QoS flow. Note that the reception of this downlink SDAP data PDU may be performed via a DRB whose RLC bearer is associated with the MCG.

[0272] When some or all of the following (Condition 5-1) to (Condition 5-3) are satisfied, the terminal device 100 performs end marker processing when the DRB of the QoS flow to DRB mapping rule stored for the second QoS flow (i.e., the DRB corresponding to the already stored first QoS flow) is a DRB that does not correspond to the second information received from the RRC of the terminal device 100 in the above-mentioned first embodiment. Furthermore, even when some or all of the following (Condition 5-1) to (Condition 5-3) are satisfied, the terminal device 100 does not perform end marker processing when the DRB of the QoS flow to DRB mapping rule stored for the second QoS flow is a DRB that corresponds to the second information received from the RRC of the terminal device 100. Note that the end marker processing is processing of constructing an end marker control PDU, mapping it to the DRB before the change, and transmitting it to a lower layer.

[0273] (Condition 5-1): In step S105 in the first embodiment, the second information is notified to an SDAP associated with at least a DRB that satisfies the second condition.

[0274] (Condition 5-2): The QoS flow to DRB mapping rule stored for the first QoS flow is different from the QoS flow to DRB mapping rule of the received downlink SDAP data PDU. In other words, for the second QoS flow, the DRB associated with the QoS flow to DRB mapping rule received in the newly received downlink SDAP data PDU has changed from the DRB associated with the stored QoS flow to DRB mapping rule.

[0275] (Condition 5-3): The uplink SDAP header is set in the DRB of the stored QoS flow to DRB mapping rule.

[0276] Furthermore, if a QoS flow to DRB mapping rule for the second QoS flow does not exist (is not stored) and a default DRB is set, the terminal device 100 may perform some or all of the following processing.

[0277] (Process 1) If the default DRB is a DRB that does not correspond to the second information received from the RRC of the terminal device 100 in the above-described first embodiment, an end marker control PDU is constructed, mapped to the default DRB, and transmitted to a lower layer.

[0278] (Process 2) When the default DRB is a DRB corresponding to the second information received from the RRC of the terminal device 100 in the above-described first embodiment, part or all of the construction of an end marker control PDU, mapping of the constructed end marker control PDU to the default DRB, and transmission to a lower layer are not performed.

[0279] The QoS flow to DRB mapping rule may be a QoS flow to DRB mapping rule for the uplink (UL QoS flow to DRB mapping rule).

[0280] When receiving an RRC reconfiguration message, if the RRC reconfiguration message includes SCG synchronization reconfiguration parameters, the terminal device 100 determines whether to immediately execute some or all of the SCG synchronization reconfiguration processes. When the terminal device 100 determines not to immediately execute some or all of the SCG synchronization reconfiguration processes, it executes the unexecuted SCG synchronization reconfiguration processes at the time of SCG (re)activation. The terminal device 100 determines not to immediately execute the processes if, for example, some or all of the following conditions are met: -SCG deactivation is in progress The synchronized reconfiguration of the SCG is accompanied by a change in the master node security key (KgNB or KeNB) or a change in the AS security key generated from the master node security key. The synchronized reconfiguration of the SCG is accompanied by a change in the security key (S-KgNB or S-KeNB) of the secondary node or a change in the AS security key generated from the security key of the secondary node. There is no radio bearer using the master key among the radio bearers associated with the SCG RLC bearer. All radio bearers associated with SCG RLC bearers must use secondary keys. The base station device 200 has instructed it to be executed at the time of SCG (re)activation.

[0281] This makes it possible to suppress the implementation of SCG (re)activation due to the execution of synchronized reconfiguration of the SCG, and to suppress power consumption of the terminal device 100.

[0282] Furthermore, the base station device 200 does not include a synchronization-based reconfiguration parameter in the SCG configuration parameters of the RRC reconfiguration message when it determines that it does not want the SCG of the terminal device 100 to immediately execute synchronization-based reconfiguration of the SCG. The base station device 200 determines that it does not want to execute synchronization-based reconfiguration immediately when, for example, some or all of the following conditions are met: -SCG deactivation is in progress The synchronized reconfiguration of the SCG is accompanied by a change in the master node security key (KgNB or KeNB) or a change in the AS security key generated from the master node security key. The synchronized reconfiguration of the SCG is accompanied by a change in the security key (S-KgNB or S-KeNB) of the secondary node or a change in the AS security key generated from the security key of the secondary node. There is no radio bearer using the master key among the radio bearers associated with the SCG RLC bearer. All radio bearers associated with SCG RLC bearers must use secondary keys.

[0283] A radio bearer that uses a master key may be a radio bearer in which a parameter (keyToUse) indicating whether to use the master key or the secondary key is set to master (or primary). A radio bearer that uses a secondary key may be a radio bearer in which a parameter (keyToUse) indicating whether to use the master key or the secondary key is set to secondary.

[0284] This makes it possible to suppress the implementation of SCG (re)activation due to the execution of synchronous resetting, and to suppress power consumption of the terminal device 100.

[0285] Furthermore, if the RRC reconfiguration message received from the base station device 200 during SCG deactivation includes reconfiguration parameters with MCG synchronization but does not include reconfiguration with SCG synchronization, the terminal device 100 does not resume uplink transmission of the SCG.

[0286] This makes it possible to suppress the implementation of SCG (re)activation due to the execution of synchronous resetting, and to suppress power consumption of the terminal device 100.

[0287] Furthermore, when the terminal device 100 receives an SCG deactivation instruction from the base station device 200, it performs (Processing A) on the radio bearer that satisfies (Condition A).

[0288] (Condition A) is that it is an SCG bearer, or that it is a split bearer and the primary path is set in the SCG.

[0289] (Processing A) is a process in which the PDCP entity of a radio bearer that satisfies (Condition A) immediately transmits or discards data that has not been transmitted. (Processing A) may also be a process in which, when a re-establishment request for the PDCP entity of a radio bearer that satisfies (Condition A) is made, the data that has not been transmitted is not immediately transmitted during the re-establishment process of the PDCP entity, but is transmitted at the time of (or after) SCG (re)activation. (Processing A) is a process in which the PDCP entity of a radio bearer that satisfies (Condition A) discards an SDAP control PDU received from an upper layer.

[0290] This makes it possible to suppress the implementation of SCG (re)activation due to the occurrence of uplink transmission, and to suppress power consumption of the terminal device 100.

[0291] Furthermore, when the RRC of the terminal device 100 receives an SCG deactivation instruction from the base station device 200, it notifies (information A) to an SDAP associated with a radio bearer (DRB) that satisfies (condition A).

[0292] (Information A) is information indicating that uplink transmission by the DRB is prohibited (stopped), or that the cell group to which the DRB is associated is in the process of deactivation, and so on, and thus uplink transmission by the DRB is not possible.

[0293] This makes it possible to suppress the implementation of SCG (re)activation due to the occurrence of uplink transmission, and to suppress power consumption of the terminal device 100.

[0294] Furthermore, in the SDAP, if the DRB corresponding to the first QoS flow is changed and the DRB before the change is the DRB notified by the RRC, the terminal device 100 does not transmit an SDAP control SDU to the DRB before the change.

[0295] Furthermore, the base station device 200 may be configured not to generate an end marker when the terminal device 100 is undergoing SCG deactivation. For example, during SCG deactivation, the base station device 200 performs control such that a QoS flow associated with a DRB that is an SCG bearer or a split bearer and for which a primary path is set in the SCG is not re-associated with another DRB, thereby preventing an end marker from being generated. Furthermore, the base station device 200 performs control such that an end marker is not generated, for example, before the SCG deactivation instruction in step S104 in the above-mentioned first embodiment or in the SCG deactivation instruction, some or all of the QoS flows associated with a DRB that satisfies at least the second condition are associated with a DRB that does not satisfy at least the second condition.

[0296] This makes it possible to suppress the implementation of SCG (re)activation due to the occurrence of uplink transmission, and to suppress power consumption of the terminal device 100.

[0297] Furthermore, when UL data occurs (arrives), the terminal device 100 may be instructed by the base station device 200 whether to issue an SCG (re)activation request to the base station device 200 or to perform SCG (re)activation spontaneously by the terminal device 100. That is, the terminal device 100 performs, for example, the following process.

[0298] When the RRC of the terminal device 100 receives an SCG deactivation instruction from the base station device 200, it transmits (notification A) to the PDCP entity of the radio bearer corresponding to (condition A). (Notification A) is a notification indicating that SCG deactivation is in progress or that uplink transmission on the SCG side is prohibited (suspended). When the PDCP entity of the radio bearer corresponding to (condition A) receives data from a higher layer, the PDCP entity of the terminal device 100 notifies the RRC of the terminal device 100 that UL data has been generated. The RRC of the terminal device 100 generates an SCG reactivation request and transmits it to the base station device 200. When the RRC of the terminal device 100 receives the SCG reactivation instruction from the base station device 200, it transmits a notification indicating that the SCG has been (re)activated, or that uplink transmission on the SCG side has started (restarted), to the PDCP entity of the radio bearer that transmitted the second notification.

[0299] Alternatively, when UL data occurs in the MAC, the terminal device 100 executes a random access procedure to enable uplink transmission. If there is synchronized reconfiguration of the SCG that was not executed immediately, the terminal device 100 executes it in advance.

[0300] This allows the terminal device 100 to perform appropriate processing when uplink transmission occurs on the RLC bearer on the SCG side during SCG deactivation. This also allows the terminal device 100 to notify the base station device 200 that uplink transmission has occurred on the RLC bearer on the SCG side during SCG deactivation, or to perform SCG (re)activation autonomously or in response to an instruction from the base station device 200.

[0301] (Other embodiments) The above-described embodiments may be combined with each other. Furthermore, the messages in the sequence do not need to be transmitted and received in the order described above, and the order may be reversed. Furthermore, some of the messages in the sequence may not be transmitted and received. For example, the processing during SCG deactivation in the terminal device 100 may be performed as long as the terminal device 100 is undergoing SCG deactivation, and transmission and reception of messages in the sequence may be omitted.

[0302] In each embodiment, what is described as a function or process of the terminal device 100 may be a function or process of the base station device 200. In each embodiment, what is described as a function or process of the base station device 200 may be a function or process of the terminal device 100.

[0303] In each embodiment, a "radio bearer" may be a signaling radio bearer, a data radio bearer, or both a signaling radio bearer and a data radio bearer.

[0304] Furthermore, in each embodiment, "A may be replaced with B" may include replacing B with A in addition to replacing A with B.

[0305] Furthermore, in each embodiment, if condition "A" and condition "B" are contradictory, condition "B" can be understood as another condition of condition "A."

[0306] In each embodiment, examples of terminal devices and base station devices are described, but the disclosed technology is not limited to these and can be applied to various devices, such as electronic devices mounted on automobiles, trains, airplanes, artificial satellites, etc., electronic devices transported by drones, etc., robots, AV equipment, home appliances, office equipment, vending machines, and other household equipment.

[0307] In addition, although the embodiments have been described using E-UTRA and NR as radio access technologies and EPC and 5GC as core networks as examples, the application of the disclosed technology is not limited to these. For example, the disclosed technology may be applied to radio access technologies and networks of different generations, such as 6th generation and 7th generation.

[0308] Although the drawings are used to describe each embodiment, the specific configuration is not limited to the illustrated form.

[0309] The following additional notes are provided regarding the above-described embodiments.

[0310] (Supplementary Note 1) A wireless communication device comprising: a transmitter that transmits a message to another wireless communication device; and a processor that executes processing on the message transmitted by the transmitter, The processing unit When a first parameter is included in a first RRC (Radio Resource Control) message transmitted to the other wireless communication device and a second parameter is included in a first DRB (Data Radio Bearer) setting parameter included in the first RRC message, a third parameter is included in the first DRB setting parameter. A wireless communication device comprising:

[0311] (Supplementary Note 2) A wireless communication device comprising: a transmitter that transmits a message to another wireless communication device; and a processor that executes processing on the message transmitted by the transmitter, The processing unit When a second parameter is included in a first DRB (Data Radio Bearer) setting parameter included in a first RRC (Radio Resource Control) message transmitted to the other wireless communication device, a secondary cell group set in the other wireless communication device is activated. A wireless communication device comprising:

[0312] (Supplementary Note 3) A wireless communication device comprising: a transmitter that transmits a message to another wireless communication device; and a processor that executes processing on the message transmitted by the transmitter, The processing unit When a first parameter is included in a first RRC (Radio Resource Control) message transmitted to the other wireless communication device, a second parameter is not included in a first DRB (Data Radio Bearer) setting parameter included in the first RRC message. A wireless communication device comprising:

[0313] (Appendix 4) The first DRB setting parameter is: Configuration parameters for a first DRB established by the other wireless device; The first DRB is configured to transmit a Packet Data Convergence Protocol (PDCP) status report and is associated with a secondary cell group. 4. The wireless communication device according to claim 1, wherein:

[0314] (Supplementary Note 5) The first parameter is a parameter indicating that the secondary cell group is to be deactivated. 5. The wireless communication device according to claim 4,

[0315] (Supplementary Note 6) The second parameter is a parameter instructing the PDCP entity corresponding to the first DRB to re-establish PDCP or a parameter instructing PDCP data recovery. 5. The wireless communication device according to claim 4,

[0316] (Supplementary Note 7) The third parameter is a PDCP configuration parameter that does not include a parameter for configuring the transmission of a PDCP status report. 5. The wireless communication device according to claim 4,

[0317] (Supplementary Note 8) A wireless communication device comprising: a receiving unit that receives a message from another wireless communication device; and a processing unit that executes processing on the message received by the receiving unit, The processing unit When a first parameter is included in a first RRC (Radio Resource Control) message received from the other wireless communication device and a second parameter is included in a first DRB (Data Radio Bearer) setting parameter included in the first RRC message, the PDCP status report is not transmitted. A wireless communication device comprising:

[0318] (Supplementary Note 9) The first DRB setting parameter is: The setting parameters for the first DRB established by the device itself, The first DRB is configured to transmit a Packet Data Convergence Protocol (PDCP) status report and is associated with a secondary cell group. 9. The wireless communication device according to claim 8,

[0319] (Supplementary Note 10) A communication method in a wireless communication device that transmits a message to another wireless communication device, When a first parameter is included in a first RRC (Radio Resource Control) message transmitted to the other wireless communication device and a second parameter is included in a first DRB (Data Radio Bearer) setting parameter included in the first RRC message, a third parameter is included in the first DRB setting parameter. A communication method comprising the steps of:

[0320] (Supplementary Note 11) A computer included in a wireless communication device that transmits a message to another wireless communication device, When a first parameter is included in a first RRC (Radio Resource Control) message transmitted to the other wireless communication device and a second parameter is included in a first DRB (Data Radio Bearer) setting parameter included in the first RRC message, a third parameter is included in the first DRB setting parameter. A communication program characterized by causing a process to be executed. [Explanation of symbols]

[0321] 110, 210 processors 120, 220 storage 121, 221 Wireless Communications Program 122 Terminal side program 130, 230 memory 140, 240 wireless communication circuit 222 Base station program 250 NI

Claims

1. A wireless communication device comprising: a transmitter that transmits a message to another wireless communication device; and a processor that executes processing on the message transmitted by the transmitter, The processing unit Controlling a first RRC (Radio Resource Control) message transmitted to the other wireless communication device to include: a first parameter indicating that a secondary cell group is to be deactivated; a second parameter instructing PDCP re-establishment or PDCP data recovery; and a first DRB (Data Radio Bearer) setting parameter that is a setting parameter for a first DRB (Data Radio Bearer) established by the other wireless communication device, the first DRB setting parameter including a third parameter that is PDCP setting information set to release a setting for PDCP status report transmission set in the first DRB. A wireless communication device comprising:

2. The first DRB is configured to transmit a Packet Data Convergence Protocol (PDCP) status report and is associated with a secondary cell group.

2. The wireless communication device according to claim 1.

3. The third parameter is a PDCP configuration parameter that does not include a parameter for configuring the transmission of a PDCP status report.

3. The wireless communication device according to claim 2.

4. A wireless communication device comprising: a receiving unit that receives a message from another wireless communication device; and a processing unit that executes processing on the message received by the receiving unit, The processing unit When a first RRC (Radio Resource Control) message received from the other wireless communication device includes a first parameter indicating that a secondary cell group is to be deactivated, and a first DRB (Data Radio Bearer) configuration parameter included in the first RRC message includes a second parameter, the PDCP status report is not transmitted regardless of whether a third parameter is included in the first DRB configuration parameter. A wireless communication device comprising:

5. 1. A communication method in a wireless communication device for transmitting a message to another wireless communication device, comprising: a first RRC (Radio Resource Control) message transmitted to the other wireless communication device includes a first parameter indicating that a secondary cell group is to be deactivated, a second parameter instructing PDCP re-establishment or instructing PDCP data recovery, and a first DRB (Data Radio Bearer) setting parameter that is a setting parameter for a first DRB (Data Radio Bearer) established by the other wireless communication device, the first DRB setting parameter including a third parameter that is PDCP setting information set to release a setting for PDCP status report transmission that is set for the first DRB; A communication method comprising the steps of:

6. A computer included in a wireless communication device that transmits a message to another wireless communication device, a first RRC (Radio Resource Control) message transmitted to the other wireless communication device includes a first parameter indicating that a secondary cell group is to be deactivated, a second parameter instructing PDCP re-establishment or instructing PDCP data recovery, and a first DRB (Data Radio Bearer) setting parameter that is a setting parameter for a first DRB (Data Radio Bearer) established by the other wireless communication device, the first DRB setting parameter including a third parameter that is PDCP setting information set to release a setting for PDCP status report transmission that is set for the first DRB; A communication program characterized by causing a process to be executed.

Images