First wireless communication device, second wireless communication device, and wireless communication system

Abstract

This second radio communication device comprises a second transmitting unit for transmitting a message to the second radio communication device, and a second processing unit, wherein: if the second radio communication device resumes secondary cell group transmission with respect to a first radio bearer of the second radio communication device when the first radio bearer is in a suspended state, the second processing unit includes a first parameter in a first RRC message transmitted to the second radio communication device and does not include a second parameter, and if the second radio communication device does not resume the secondary cell group transmission with respect to the first radio bearer, the second processing unit includes the first parameter and the second parameter in the first RRC message transmitted to the second radio communication device.

Description

[Technical Field]

[0001] The present invention relates to a wireless communication device. [Background technology]

[0002] Currently, wireless communication networks using mobile devices (smartphones, feature phones, etc.) are expanding. With the expansion of wireless communication, there is a demand for even faster speeds and larger capacities.

[0003] DC (Dual Connectivity) is a technology that can achieve high speed and large capacity. is a technology in which a terminal device wirelessly connects to base station devices of 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).

[0004] Furthermore, as the generation of wireless communication standards advances, for example, 3.9G, 4G (Four-Generation), and 4G-advanced radio access technologies (RATs) such as the EU MR-DC (Multi Radio Dual Connectivity) is a DC technology that uses eNodeB (hereinafter sometimes referred to as eNB), a base station device that supports TRA (Evolved Terrestrial Radio Access), and gNodeB (hereinafter sometimes referred to as gNB), a base station device that supports NR (New Radio), a radio access technology for 5G (Five-Generation) and 5G-Advanced. MR-DC is a DC technology that uses a master base station device and a secondary base station device. This also includes cases where both the DC and the gNB are DCs.

[0005] When the amount of data to be transmitted and received in MR-DC 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, when the amount of data to be transmitted and received in MR-DC is small, it is considered to save power by temporarily suspending data transmission and reception with the secondary base station device, for example, by deactivating the cell group (secondary cell group) belonging to the secondary base station device.

[0006] Techniques relating to MR-DC are described in the following prior art documents. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] 3GPP TS36.133 LTE-A Radio Measurement Specification [Non-patent document 2] 3GPP TS36.300 LTE-A Overview Specifications [Non-patent document 3] 3GPP TS36.211 LTE-A PHY Channel Specification [Non-patent document 4] 3GPP TS36.212 LTE-A PHY Coding Specification [Non-Patent Document 5] 3GPP TS36.213 LTE-A PHY Procedure Specification [Non-patent document 6] 3GPP TS36.214 LTE-A PHY Measurement Specification [Non-Patent Document 7] 3GPP TS36.321 LTE-A MAC Specification [Non-patent document 8] 3GPP TS36.322 LTE-A RLC Specification [Non-Patent Document 9] 3GPP TS36.323 LTE-A PDCP Specification [Non-Patent Document 10] 3GPP TS36.331 LTE-A RRC Specification [Non-Patent Document 11] 3GPP TS36.413 LTE-A S1 Specification [Non-Patent Document 12] 3GPP TS36.423 LTE-A X2 Specification [Non-Patent Document 13] 3GPP TS36.425 LTE-A Xn Specification [Non-Patent Document 14] 3GPP TR36.912 NR Radio Access Overview [Non-Patent Document 15] 3GPP TR38.913 NR Requirements [Non-Patent Document 16] 3GPP TR38.913 NR Requirements [Non-Patent Document 17] 3GPP TR38.801 NR Network Architecture Overview [Non-Patent Document 18] 3GPP TR38.802 NR PHY Overview [Non-Patent Document 19] 3GPP TR38.803 NR RF Overview [Non-Patent Document 20] 3GPP TR38.804 NR L2 Overview [Non-Patent Document 21] 3GPP TR38.900 NR High Frequency Overview [Non-Patent Document 22] 3GPP TS38.300 NR Overview Specifications [Non-Patent Document 23] 3GPP TS37.340 NR Multiple Access Overview Specification [Non-Patent Document 24] 3GPP TS38.201 NR PHY Specification Overview [Non-Patent Document 25] 3GPP TS38.202 NR PHY Service Overview Specification [Non-Patent Document 26] 3GPP TS38.211 NR PHY Channel Specification [Non-Patent Document 27] 3GPP TS38.212 NR PHY Coding Specification [Non-patent document 28] 3GPP TS38.213 NR PHY Data Channel Procedure Specification [Non-Patent Document 29] 3GPP TS38.214 NR PHY Control Channel Procedure Specification [Non-Patent Document 30] 3GPP TS38.215 NR PHY Measurement Specification [Non-Patent Document 31] 3GPP TS38.321 NR MAC Specification [Non-Patent Document 32] 3GPP TS38.322 NR RLC Specification [Non-Patent Document 33] 3GPP TS38.323 NR PDCP Specification [Non-Patent Document 34] 3GPP TS37.324 NR SDAP Specification [Non-Patent Document 35] 3GPP TS38.331 NR RRC Specification [Non-Patent Document 36] 3GPP TS38.401 NR Architecture Overview Specification [Non-Patent Document 37] 3GPP TS38.410 NR Core Network Overview Specification [Non-Patent Document 38] 3GPP TS38.413 NR Core Network AP Specification [Non-Patent Document 39] 3GPP TS38.420 NR Xn Interface Overview Specification [Non-Patent Document 40] 3GPP TS38.423 NR XnAP Specification [Non-Patent Document 41] 3GPP TS38.470 NR F1 Interface Overview Specification [Non-Patent Document 42] 3GPP TS38.473 NR F1AP [Non-Patent Document 43] 3GPP R2-2111683 Introduction of efficient SCG activation / deactivation Summary of the Invention [Problem to be solved by the invention]

[0008] 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.

[0009] For example, Non-Patent Document 43 shows a proposed procedure for a base station device to deactivate or activate a secondary cell group of a terminal device. However, according to Non-Patent Document 43, when a terminal device whose radio bearer is in a suspended state receives a message from a base station device that includes a synchronous reconfiguration parameter, even if the same message includes a parameter indicating that the secondary cell group should be deactivated, transmission using the secondary cell group will be resumed, resulting in unnecessary power consumption.

[0010] Therefore, one disclosure provides a wireless communication device that suppresses power consumption of a terminal device when activating communication between the terminal device in a secondary cell group inactive state and a secondary base station device in MR-DC. [Means for solving the problem]

[0011] A first wireless communication device (base station device) comprising a second transmission unit that transmits a message to a second wireless communication device (terminal device), and a second processing unit, wherein when a first wireless bearer of the second wireless communication device is in a suspended state, if the second wireless communication device resumes secondary cell group transmission for the first wireless bearer, the second processing unit includes a first parameter but does not include a second parameter in a first RRC message to be sent to the second wireless communication device, and if the second wireless communication device does not resume secondary cell group transmission for the first wireless bearer, the second processing unit includes the first parameter and the second parameter in the first RRC message to be sent to the second wireless communication device. [Effects of the Invention]

[0012] The present disclosure makes it possible to suppress power consumption of a terminal device when activating communication between a terminal device in a secondary cell group inactive state and a secondary base station device in MR-DC. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a communication system 10. As shown in FIG. [Figure 2] FIG. 2 illustrates an example of the configuration of the base station device 200. As shown in FIG. [Figure 3] FIG. 3 is a diagram illustrating an example of the configuration of the terminal device 100. As shown in FIG. [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 illustrating an example of a message format of RRCReconfiguration. [Figure 7] FIG. 7 is a diagram showing an example of the configuration of a cell group in the communication system 10. As shown in FIG. [Figure 8] FIG. 8 is a diagram showing examples of types of MR-DC. [Figure 9]FIG. 9 is a diagram illustrating an example of resetting with synchronization. [Figure 10] FIG. 10 is a diagram illustrating an example in which an end marker control PDU is transmitted. [Figure 11] FIG. 11 is a diagram showing an example of a sequence in which the state of the SCG transitions to inactive. [Figure 12] FIG. 12 is a diagram showing an example of a sequence in which the terminal device 100 receives an RRC reconfiguration message during SCG deactivation. [Figure 13] FIG. 13 is a diagram showing an example of a sequence of UL data arrival during SCG deactivation. [Figure 14] FIG. 14 is a diagram showing an example of a procedure for transitioning from the RRC connected mode to the RRC inactive mode and from the RRC inactive mode to the RRC connected mode. [Figure 15] FIG. 15 is a diagram showing an example of a sequence for receiving an RRC message while a radio bearer is suspended on the SCG side of the terminal device 100. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present embodiment will be described in detail below with reference to the drawings. The problems and examples in this specification are merely examples and do not limit the scope of the rights of the present application. In particular, even if the expressions used are different, the technology of the present application can be applied as long as they are technically equivalent, and do not limit the scope of the rights.

[0015] <Configuration example of communication system 10> FIG. 1 is a diagram showing an example of the configuration of a communication system 10. The communication system 10 includes a terminal device 100, base station devices 200-1 and 200-2, and a core network 300. The communication system 10 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. When communicating using MR-DC, for example, 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 is referred to as an MN (Master Node), and the secondary base station device is referred to as an SN (Secondary Node). :Secondly Node).

[0016] The terminal device 100 is wirelessly connected to one or both of the base station device 200-1 and the base station device 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 It is a tablet terminal or smartphone that supports either or both of the above.

[0017] Base station devices 200-1 and 2 (hereinafter, sometimes referred to as base station device 200) are communication devices that are wirelessly connected to terminal device 100 and perform wireless communication. Base station devices 200-1 and 2 are, for example, wired connected to each other and perform communication. Base station device 200 is, for example, wired connected to core network 300 and performs communication. Base station device 200 is, for example, a base station device that is either an eNodeB that provides E-UTRA as a RAT or a gNodeB that provides NR as a RAT.

[0018] The core network 300 is a network corresponding to a certain generation, such as a core network corresponding to 5G (hereinafter, may be referred to as 5GC) or an EPC (Evolved Packet Core) corresponding to 4G.

[0019] The MR-DC realized in the communication system 10 will be described in detail later.

[0020] <Configuration Example of Base Station Device 200> 2 is a diagram illustrating an example of the configuration of the base station device 200. The base station device 200 includes a CPU (Central Processing Unit) 210, a storage 220, a memory 230, a wireless communication circuit 24, and a 0 and a network interface 250.

[0021] The storage 220 is an auxiliary storage device that stores programs and data, such as a flash memory, a hard disk drive (HDD), or a solid state drive (SSD). The storage 220 stores a wireless communication program 221 and a base station side program 222.

[0022] 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.

[0023] 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 a signal transmitted from the terminal device 100 via the wireless communication circuit 240, and transmits a signal to the terminal device 100, for example.

[0024] The NI (network interface) 250 is used to connect to other base station devices 200, for example. The NI 250 is a communication device that realizes inter-station communication. The NI 250 is, for example, a communication device that connects to the core network 300 (communication devices that make up the core network 300) and communicates with the core network 300. The NI 250 is, for example, a network interface card (NIC). The base station device 200 receives signals from other communication devices and transmits signals to other communication devices via the NI 250.

[0025] The CPU 210 is a processor that loads a program stored in the storage 220 into the memory 230, executes the loaded program, configures each unit, and realizes each process.

[0026] The CPU 210 performs wireless communication processing by executing the wireless communication program 221. The wireless communication processing is processing for wirelessly connecting to the terminal device 100, wirelessly communicating with the terminal device 100, and relaying communication between the terminal device 100 and other communication devices.

[0027] The CPU 210 executes the base station side program 222 to configure a second transmitting unit, a second receiving unit, and a second 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.

[0028] <Configuration example of terminal device 100> 3 is a diagram illustrating an example of the configuration of the terminal device 100. The terminal device 100 is a communication device having a CPU 110, a storage 120, a memory 130, and a wireless communication circuit 140.

[0029] 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 terminal-side wireless communication program 121 and a terminal-side program 122.

[0030] 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.

[0031] 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, for example, a signal transmitted from the base station device 200 via the wireless communication circuit 140 and transmits a signal to the base station device 200. The wireless communication circuit 140 is, for example, a network card that supports wireless connection.

[0032] The CPU 110 is a processor that loads a program stored in the storage 120 into the memory 130, executes the loaded program, configures each unit, and realizes each process.

[0033] The CPU 110 performs terminal-side wireless communication processing by executing the terminal-side wireless communication program 121. The terminal-side wireless communication processing is processing for wirelessly connecting to the base station device 200 and performing wireless communication with the base station device 200 or communication with another communication device via the base station device 200.

[0034] The CPU 110 executes the terminal-side program 122 to configure a transmitting unit, a receiving unit, and a 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.

[0035] <Protocol stack> An example of a protocol stack of the communication system 10 will be described. In the communication system 10, a series of protocols for transmitting and receiving data, shown in a hierarchical structure, is called a protocol stack. In the following example, 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.

[0036] Below, U-Plane (User Plane) and C-Plane (Control Plane) The protocol stack will now be described. U-Plane indicates, for example, data signals (messages) of user data that are transmitted and received. C-Plane indicates, for example, control signals (messages) that are transmitted and received in communication.

[0037] Figure 4 is a diagram showing an example of a protocol stack for the U-Plane when core network 300 is 5GC. Figure 5 is a diagram showing an example of a protocol stack for the C-Plane when core network 300 is 5GC. In Figures 4 and 5, SDAP, PDCP, RLC, MAC, PHY, NAS, and RRC indicate the names of layers, respectively. Hereinafter, SDAP, PDCP, RLC, MAC, PHY, NAS, and RRC may be referred to as the SDAP sublayer, PDCP sublayer, RLC sublayer, MAC sublayer, PHY sublayer, NAS sublayer, and RRC sublayer, respectively, or the SDAP layer, PDCP layer, RLC layer, MAC layer, PHY layer, NAS layer, and RRC layer, respectively. Furthermore, SDAP, PDCP, RLC, MAC, PHY, NAS, and RRC may be referred to as the SDAP entity, PDCP entity, RLC entity, MAC entity, PHY entity, NAS entity, and RRC entity, respectively. When the core network 300 is the EPC, the protocol stack of the U-Plane is a protocol stack without SDAP in Fig. 4, that is, a protocol stack consisting of PDCP, RLC, MAC, and PHY. When the core network 300 is the EPC, the protocol stack of the C-Plane is such that the NAS exists in the MME, whereas the NAS exists in the AMF in Fig. 5.

[0038] The functions in each layer may be common or different depending on whether the RAT is E-UTRA or NR. In the following description, unless E-UTRA or NR is specified, the functions in each layer are common to both E-UTRA and NR.

[0039] In Figure 4, the U-Plane is SDAP (Service Data Adaptation Protocol), It consists of 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).

[0040] 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. The direction from the base station device 200 to the terminal device is sometimes called downlink (downlink, DL), and the direction from the terminal device 100 to the base station device is sometimes called uplink (uplink, UL). In the terminal device 100 and the base station device 200, PHY communicates with the MAC and transport channels (transport channels) that are higher layers. The PHY and MAC are connected by a transport channel. moves.

[0041] MAC is the medium access control layer, which handles transport channel and logical channel (LCH) mapping, MAC SDU multiplexing / demultiplexing, scheduling reports, error correction through HARQ (Hybrid Automatic Repeat reQuest), and priority control. In the terminal device 100 and the base station device 200, the MAC is connected to the RLC, which is an upper layer, via a logical channel. Data moves between the MAC and the RLC via the logical channel.

[0042] SDU (Service Data Unit) is passed from the upper sublayer to each sublayer. A PDU (Protocol Data Unit) is a sub-layer term used to describe data that is passed from a lower sub-layer to a lower sub-layer.

[0043] In addition, RLC, PDCP, and SDAP have control PDUs, which are sometimes called control PDUs. To distinguish them from control PDUs, other PDUs are sometimes called data PDUs.

[0044] RLC is a radio link control layer and has three modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). RLC is a P layer of PDCP, which is an upper layer on the transmitting side. It transfers DUs, assigns sequence numbers (for UM and AM), segments data (for UM and AM), resegments data (for AM), reassembles SDUs (for UM and AM) on the receiving side, detects duplicates (for AM), and discards RLC SDUs (for UM and AM). In addition, E-UTRA RLC also has other functions such as data combining on the transmitting side, and reordering and in-order delivery on the receiving side.

[0045] PDCP is a packet data convergence protocol layer that handles U-Plane and C-Plane data transfer, PDCP sequence number management, header compression / decompression, encryption / decryption, integrity protection / integrity verification, timer-based SDU discarding, and split bearer rules. In addition, E-UTRA PDCP may have functions such as timer-based SDU discard, reordering and in-order delivery only in the case of a split bearer.

[0046] SDAP is a service data adaptation protocol layer that maps Quality of service (QoS) flows to Data Radio Bearers (DRBs) and marks QoS flow identifiers (QFIs) on downlink (DL) and uplink (UL) packets. etc.

[0047] The upper layers of the U-Plane include, for example, IP (Internet Protocol), TCP (Transmission Control Protocol), UDP (User Datagram Protocol), Layers such as IP, TCP, UDP, and Ethernet may be included in the PDU layer, and IMS (IP Multimedia Subsystem) may be included in the application layer.

[0048] In FIG. 5, the C-Plane of the AS (Access Stratum) is composed of PDCP, RLC, MAC, PHY, and RRC (Radio Resource Control), 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. Regarding PDCP, RLC, MAC, and PHY, It is the same as U-Plane.

[0049] RRC provides functions such as broadcasting of system information (SI) related to AS and NAS, paging, establishment / maintenance / release of RRC connections between the terminal device 100 and the base station device 200, addition / modification / release of carrier aggregation (CA), addition / modification / release of dual connectivity (DC), security functions including management of security keys, establishment / setting / maintenance / release of signaling radio bearers (SRBs) and data radio bearers (DRBs), mobility functions, QoS management functions, terminal device measurement reports and reporting. It is responsible for control, Radio Link Failure (RLF) detection and recovery, and forwarding of NAS messages.

[0050] The NAS handles authentication, mobility management, security control, etc.

[0051] If the device of the core network 300 is an EPC (Evolved Packet Core), In the U-Plane, there is no SDAP. In addition, when the device of the core network 300 is an EPC, the NAS of the C-Plane terminates between the terminal device 100 and an MME (Mobility Management Entity) which is a device of the core network 300.

[0052] <channel> The following describes channels used in the communication system 10. Below, examples of channels corresponding to NR are shown, but the channels used are not limited to the following. Furthermore, channels with the same names may also be used for the same or similar purposes in RATs other than NR, such as E-UTRA.

[0053] <1. Physical Channel> The PBCH (Physical Broadcast CHannel) is a channel used to transmit broadcast information from the base station device 200 to the terminal device 100.

[0054] The PDCCH (Physical Downlink Control CHannel) is a channel from the base station device 200 to the terminal device. 100, and transmits downlink control information (Downlink Control Information: DCI) and the like. This is the channel used for

[0055] A PDSCH (Physical Downlink Shared CHannel) is a channel used to transmit data from an upper layer from the base station device 200 to the terminal device 100.

[0056] A PUCCH (Physical Uplink Control CHannel) is transmitted from the terminal device 100 to the base station device 2. 00 to transmit uplink control information (UCI) etc. This is the channel used for

[0057] A PUSCH (Physical Uplink Shared CHannel) is a channel used to transmit data from an upper layer from the terminal device 100 to the base station device 200.

[0058] 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.

[0059] <2. Transport Channel> The BCH (Broadcast Channel) is mapped to the PBCH, which is a physical channel.

[0060] The DL-SCH (Downlink Shared Channel) is mapped to the PDSCH, which is a physical channel.

[0061] A PCH (Paging Channel) is mapped to a PDSCH, which is a physical channel.

[0062] The UL-SCH (Downlink Shared Channel) is mapped to the PUSCH, which is a physical channel.

[0063] Random Access Channel(s) (RACH) are mapped to a PRACH, which is a physical channel.

[0064] <3. Logical Channel> BCCH (Broadcast Control Channel) is a downlink channel used to broadcast system information. It is a link channel and is mapped to the BCH of the transport channel.

[0065] A PCCH (Paging Control Channel) is a downlink channel for carrying paging messages and is mapped to the PCH of the transport channel.

[0066] The CCCH (Common Control Channel) is a channel for transmitting control information (such as an RRC message) 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. The downlink is mapped to the transport channel DL-SCH, and the uplink is mapped to the transport channel DL-SCH. It is mapped to the UL-SCH transport channel.

[0067] DCCH (Dedicated Control Channel) is a point-to-point bidirectional channel. The channel transmits dedicated control information (such as an RRC message) between the terminal device 100 and the base station device 200, and is used for the terminal device 100 that has an RRC connection with the base station device 200. The downlink is mapped to the transport channel DL-SCH, and the uplink is mapped to the transport channel DL-SCH. It is mapped to the UL-SCH transport channel.

[0068] DTCH (Dedicated Transport Channel) is a point-to-point terminal dedicated A bidirectional channel transmits user information (user data), with the downlink mapped to the DL-SCH transport channel and the uplink mapped to the UL-SCH transport channel.

[0069] <RRCメッセージ> The RRC message is explained below. The RRC message contains information necessary for communication in a cell, including a MIB (Master Information Block), a system information group, etc. The parameters contained in the RRC message are sometimes called fields or information elements (IEs).

[0070] Furthermore, 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 (RRCConnectionSetupComplete), and an RRC connection setup message (RRCConnectionSetupComplete). These messages include the RRCConnectionSetup message, the RRCConnectionSetupComplete message, and the RRCConnectionSetupComplete message.

[0071] 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). be.

[0072] 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). In addition, messages related to the reconfiguration of the RRC connection include, for example, the RRC connection reconfiguration message (RRCConnectionReconfiguration) and the RRC connection reconfiguration message (RRCConnectionReconfiguration). Examples include a connection reconfiguration complete message (RRCConnectionReconfigurationComplete).

[0073] 6 is a diagram showing an example of a message format of RRC Reconfiguration. Format E1 is a parameter of RRC Reconfiguration.

[0074] RRC Reconfiguration includes radioBearerConfig, radioBearerConfig2, masterCellGroup, secondaryCellGroup, masterKeyUpdate, and sk-count er as a parameter.

[0075] radioBearerConfig and radioBearerConfig2 are settings related to MN terminated bearers or SN terminated bearers, and include SRB settings, DRB settings, security settings, etc. The SRB settings (DRB settings) include an SRB identifier (DRB identifier), PDCP settings, parameters instructing PDCP re-establishment, etc. The security settings include a parameter (keyToUse) that indicates whether to use a master key or a secondary key.

[0076] The masterCellGroup and secondaryCellGroup are MCG settings and SCG settings, respectively, and include a cell group identifier, an RLC bearer setting, an SpCell setting, etc. The RLC bearer setting includes a logical channel identifier, an RLC setting, a radio bearer identifier (SRB identifier or DRB identifier) ​​associated with the RLC bearer, etc. The SpCell setting includes information necessary for synchronized reconfiguration, etc.

[0077] masterKeyUpdate contains the information needed to update the master key.

[0078] The sk-counter contains the information necessary for secondary key generation.

[0079] Format E11 is a diagram showing an example of parameters of RadioBearerConfig included in RRCReconfiguration.

[0080] Format E12 is a diagram showing an example of parameters of CellGroupConfig included in RRCReconfiguration.

[0081] Format E111 is the SRB-T included in RadioBearerConfig FIG. 10 is a diagram illustrating an example of parameters of oAddMod.

[0082] Format E112 is DRB-T included in RadioBearerConfig FIG. 10 is a diagram illustrating an example of parameters of oAddMod.

[0083] Format E113 is a diagram showing an example of parameters of SecurityConfig included in RadioBearerConfig.

[0084] Format E121 is a diagram showing an example of parameters of RLC-BearerConfig included in CellGroupConfig.

[0085] Format E122 is a diagram showing an example of parameters of SpCellConfig included in CellGroupConfig.

[0086] In addition, messages related to reconfiguration of RRC connections are used to establish, configure, change, and release radio bearers, cell groups, etc., as well as to perform synchronized reconfiguration, etc., and also to establish, configure, change, and release measurement information, etc.

[0087] In addition, the RRC messages further include messages regarding re-establishment of an RRC connection, messages regarding release or suspension of an RRC connection, messages regarding resumption of an RRC connection, messages regarding the capabilities of a terminal device, messages regarding terminal information, messages regarding MCG failure information, and messages regarding SCG failure information.

[0088] In addition, in MR-DC, when the master node 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. Furthermore, 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.

[0089] Furthermore, in MR-DC, when the master node is a gNB, the gNB may configure the terminal device 100 regarding E-UTRA 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 the E-UTRA configuration as a container in an NR RRC message and transmit the message to the gNB, which is the master node.

[0090] <radio bearer> An example of a radio bearer in the communication system 10 will now be described.

[0091] <1. Signaling Radio Bearer> Signaling Radio Bearer (SRB) is a radio bearer that transmits RRC messages and NA messages. This is the radio bearer for transmitting S messages.

[0092] SRB0 is a radio bearer for RRC messages that uses the CCCH (Common Control CHannel) logical channel.

[0093] SRB1 is a radio bearer for RRC messages and NAS messages that uses a DCCH (Dedicated Control CHannel) logical channel before SRB2, which will be described later, is established.

[0094] SRB2 is a radio bearer for NAS messages and RRC messages containing logged measurement information, and is a logical channel for DCCH (Dedicated Control CHannel). The priority of SRB2 is lower than that of SRB1, and may be set by the base station apparatus 200 after AS security is activated.

[0095] SRB3 is a radio bearer for RRC messages when EN-DC or NGEN-DC or NR-DC is set in the terminal device 100, and uses the DCCH (Dedicated Control CHannel) logical channel. Note that EN-DC, NGEN-DC, and NR -DC are types of MR-DC. Details of the types of MR-DC will be described later.

[0096] <2. Data Radio Bearer> A Data Radio Bearer (DRB) is a radio bearer for transmitting user data.

[0097] <Protocol Configuration of SRB and DRB> SRB1 and SRB2 are composed of one PDCP and one or more RLC bearers. The RLC bearer is composed of an RLC and a MAC logical channel. MAC is assumed to exist for each cell group described later. The mode of RCL is AM.

[0098] SRB3 is composed of one PDCP and one RLC bearer. The mode of RLC is AM.

[0099] DRB is composed of one PDCP and one or more RLC bearers. The mode of RLC is UM or AM. When RLC is UM, DBR is called UM DBR, and when RLC is AM, it may be called AM DRB. Also, DRB is associated with one SDAP when the core network 300 is 5GC (5G-compatible core), and is associated with one EPS bearer (or EPS bearer identity) when the core network 300 is EPC. When the core network 300 is 5GC (5G-compatible core), it is associated with one SDAP, and when the core network 300 is EPC, it is associated with one EPS bearer (or EPS bearer identifier).

[0100] Note that 5GC is a core network standardized for 5G and is described in, for example, TS 23.501 and TS 23.502 of the 3GPP standard.

[0101] Furthermore, the EPC is a core network standardized for 4G, and is described in, for example, 3GPP standards TS 23.401 and TS 23.402.

[0102] <Cell Group> A cell group (CG) indicates a cell configuration in an MR-DC. In an MR-DC, cell groups are classified into a master cell group (MCG) and a secondary cell group (SCG).

[0103] Fig. 7 is a diagram showing an example of the configuration of a cell group in the communication system 10. In Fig. 6, 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 is the base station device 200 in MR-DC that provides a C-Plane connection to the core network 300. The secondary node is the base station device 200 in MR-DC that does not provide a C-Plane to the core network 300 and provides additional radio resources to the terminal device 100.

[0104] A CG is composed of one special cell (SpCell), or one SpCell and one or more secondary cells (SCell).

[0105] The SpCell in the MCG is sometimes called a Primary Cell (PCell). In addition, an SpCell in an SCG may be called a Primary Scg Cell (PSCell).

[0106] In Fig. 7, the MCG is composed of one PCell and two SCells. Also in Fig. 7, the SCG is composed of one PSCell and two SCells.

[0107] The MCG is, for example, the CG when MR-DC is not configured, or the CG belonging to the master node when MR-DC is configured.

[0108] The SCG is the CG belonging to the secondary node in MR-DC.

[0109] The PCell operates on the primary frequency in the MCG and is the cell used by the terminal device 100 for procedures such as initial connection establishment procedures or connection re-establishment procedures. The connection establishment and re-establishment procedures include random access procedures.

[0110] The PSCell is the cell used by the terminal device 100 for random access procedures or the like when performing Reconfiguration With Sync in the SCG.

[0111] The SCell is a cell that provides additional radio resources to the terminal device 100 for which carrier aggregation is configured, in addition to the SpCell.

[0112] <Type of MR-DC> The type of MR-DC will be described. MR-DC is classified into four types according to the type (corresponding generation) of the base station devices 200 of the master node and secondary node, and the type (corresponding generation) of the core network 300.

[0113] FIG. 8 is a diagram showing an example of the type of MR-DC. Hereinafter, each type of MR-DC will be described. Also, in FIG. 8, the master node is the base station device 200-1, and the secondary node is the base station device 200-2.

[0114] 8A is a diagram illustrating an example of an EN-DC (E-UTRA-NR DC). The EN-DC (E-UTRA-NR DC) is an MR-DC in which an eNB, which is an E-UTRA base station device 200, is a master node, a gNB, which is an NR base station device 200, is a secondary node, and the core network 300 is an EPC.

[0115] 8B is a diagram illustrating an example of NGEN-DC. In NGEN-DC (NG-RAN E-UTRA-NR DC), the eNB is a master node, the gNB is a secondary node, and the core network 300 is a It is an MR-DC consisting of 5GC.

[0116] 8C is a diagram illustrating an example of an NE-DC. The NE-DC (NR-E-UTRA DC) is an MR-DC in which a gNB is a master node, an eNB is a secondary node, and the core network 300 is configured as a 5GC.

[0117] 8D is a diagram showing an example of NR-DC. NR-DC (NR-NR DC) is an MR-DC in which a gNB is a master node, another gNB is a secondary node, and the core network 300 is configured as a 5GC.

[0118] 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.

[0119] 8 assumes 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.

[0120] <MR-DCのベアラタイプ> 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.

[0121] 1) MCG bearer that is MN-terminated and has an RLC bearer on the MCG side.

[0122] 2) A split bearer that is MN-terminated and has an RLC bearer present in both the MCG and SCG.

[0123] 3) SCG bearer that is MN-terminated and has an RLC bearer on the SCG side.

[0124] 4) MCG bearer that is SN-terminated and has an RLC bearer on the MCG side.

[0125] 5) Split bearer, which is SN-terminated and the RLC bearer exists in both the MCG and SCG.

[0126] 6) SCG bearer that is SN-terminated and has an RLC bearer on the SCG side.

[0127] A DRB is configured with one of the six bearer types listed above.

[0128] SRB1 and SRB2 are configured as MN-terminated MCG bearers or MN-terminated split bearers. When SRB1 and SRB2 are configured as MN-terminated split bearers, they may be called Split SBR1 and Split SBR2, respectively.

[0129] SBR3 consists of SN-Terminated SCG bearers.

[0130] 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 (priority). The primary path is specified by a cell group (MCG, 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 uplink data transmission does not exceed a threshold. If the threshold is exceeded, the terminal device 100 may transmit data to either base station device 200.

[0131] Furthermore, the security keys used in PDCP differ between MN-Terminated (master key) and SN-Terminated (secondary key).

[0132] <Synchronized reconfiguration (handover)> This section explains about synchronized reconfiguration (handover). With Sync) indicates a procedure executed in the terminal device 100 by including a parameter indicating that reconfiguration with synchronization is to be performed (reconfigurationWithSync: hereinafter, may be referred to as a reconfiguration with synchronization parameter) in the RRC reconfiguration message (RRCReconfiguration) that the base station device 200 transmits to the terminal device 100.

[0133] 9 is a diagram showing an example of synchronized reconfiguration. A terminal device (UE) 100 changes the current source PCell to a target PCell (S1). Synchronized reconfiguration parameters are included separately under parameters for MCG configuration (hereinafter, may be referred to as MCG configuration parameters) and under parameters for SCG configuration (hereinafter, may be referred to as SCG configuration parameters). In other words, when included under MCG configuration parameters, it means synchronized reconfiguration of MCG, and when included under SCG configuration parameters, it means synchronized reconfiguration of SCG.

[0134] The synchronized reconfiguration is a procedure in which the terminal device 100 changes the PCell or PSCell, and includes random access to the new (target, changed) PCell or PSCell, This includes operations such as MAC reset and PDCP data recovery (in the case of AM DRB).

[0135] In addition, synchronized re-establishment may involve changing security keys. In this case, PDCP re-establishment is also performed in addition to the above.

[0136] When a security key is changed, a new key is generated by the RRC of the terminal device 100, and the PDCP is re-established, so that the new key is applied to the PDCP.

[0137] <SDAPにおけるQos flow remapping> In the terminal device 100, the DRB to which a certain QoS flow maps is changed. At this time, an end marker control PDU is transmitted for the DRB before the change.

[0138] A QoS flow is a service data flow (SDF: Service Data Flow) that has the same QoS requirements and is identified by a QoS flow identifier (QFI). An SDF is, for example, an IP flow, an Ethernet flow, etc., and varies depending on the upper layer.

[0139] FIG. 10 is a diagram showing an example in which an end marker control PDU is transmitted. For example, in the terminal device 100, the DRB to which QoS flow 1 is associated is changed from DRB1 to DRB2 (S2). At this time, the terminal device 100 transmits the data of QoS flow 1 that has been buffered before being instructed to change, using the DRB1 before the change. Then, the terminal device 100 transmits an end marker control PDU (end marker M1) indicating that it is the last time to transmit the data of QoS flow 1 using DRB1, using DRB1. Thereby, the base station device 200 can recognize that the data of QoS flow 1 will not be transmitted using the DRB1 before the change hereafter. Note that the association between the QoS flow and the DRB may be performed by parameters included in the RRC reconfiguration message or by header information included in the downlink SDAP data PDU. The latter is called reflective mapping.

[0140] <RRC state (mode)> The RRC state of the terminal device 100 indicates the state regarding the RRC connection of the terminal device 100. The state where the RRC connection with the base station device 200 is not established may be called the RRC idle mode (RRC_IDLE). The state where the RRC connection with the base station device 200 is established may be called the RRC connected mode (RRC_CONNECTED). The RRC The state in which the connection is temporarily suspended may be called the 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 suspension instead of the RRC inactive mode.

[0141] 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.

[0142] 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 received using the DCCH logical channel.

[0143] 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 suspend setting of the RRC connection, from the base station device 200. FIG. 14A is a diagram showing a procedure for transitioning 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 the terminal device 100 a message related to the release of the RRC connection (RRCRelease) including parameters (suspendConfig) related to the suspend setting of the RRC connection. The terminal device 100 transmits the received RRCRelease message. By processing according to the message, the mobile station transitions to the RRC inactive mode. The RRCRelease may be sent using the DCCH logical channel.

[0144] 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 may be 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, etc. When MR-DC is configured in the terminal device 100, the configuration related to the SCG may be saved as a UE inactive AS context. Note that some of the parameters related to handover such as synchronous reconfiguration and some of the parameters set in the SIB may be excluded from the configuration saved as the UE inactive AS context.

[0145] The transition from the RRC inactive mode to the RRC connected mode may be performed by transmitting and receiving messages regarding RRC connection resumption between the terminal device 100 and the base station device 200. FIG. 14B is a diagram showing the transition procedure (procedure) from the RRC inactive mode to the RRC connected mode when the base station device 200 is a gNB (the master node is a gNB in the case of MR-DC) and the core network 300 is a 5GC. The terminal device 100 sends an RRC resume request message (RRCResumeRequest) to the base station device 200, receives an RRC resume message (RRCResume) from the base station device 200 as a response thereto, and performs processing according to the received RRCRes ume, whereby the terminal device 100 may transition to the RRC connected mode. When the terminal device 100 has saved the settings regarding the SCG as the UE inactive AS context and the SCG retention at the time of RRC resume is set, the base station device 200 may include the SCG settings in the RRCResume, and may include the synchronized reset of the SCG therein. Note that the RRCResumeRequest may be sent using the CCCH logical channel. Also, the RRCResume may be sent using the DCCH logical channel.

[0146] <SCG failure information> When the terminal device 100 has MR-DC set and detects an SCG failure, it may send a message (SCGFailureInformation) regarding the SCG failure information to the master node via the MCG. The SCG failure may occur, for example, when there is a physical layer out-of-synchronization on the SCG side. When a random access fails on the SCG side, when the number of RLC retransmissions on the SCG side exceeds the threshold, when a synchronized reconfiguration fails on the SCG side, when processing according to the SCG configuration cannot be performed, when the integrity verification of SRB3 fails, etc., it may be detected. When transmitting a message regarding SCG failure information, the terminal device 100 may perform a process of suspending SCG transmission for all radio bearers, that is, a process of suspending transmission of all radio bearers associated with the SCG. In the case of (NG)EN-DC, instead of SCGFailureInformation, SCGFailureInformationNR may be sent. SCGFailureInformation and SCGFailureInformationNR may be sent using the DCCH logical channel.

[0147] The base station device 200 that has received a message regarding SCG failure information from the terminal device 100 may transmit a message regarding reconfiguration of the RRC connection to the terminal device 100 in order to reconfigure the SCG.

[0148] <SCG Inactive> In (NG)EN-DC or NR-DC, communication between the secondary node and the terminal device 100 may be restricted by deactivating the SCG (SCG deactivation) set in the terminal device 100. Hereinafter, the state where the SCG is in an inactive state may be referred to as during SCG deactivation (during SCG deactivation). Also, the state where the SCG is in an active state may be referred to as during SCG (re)activation (during SCG (re)activation). Also, deactivating the SCG may be referred to as SCG deactivation (SCG deactivation). Also, activating an inactive SCG may be referred to as SCG (re)activation (SCG (re)activation).

[0149] Furthermore, hereinafter, "reactivation" and "reactivate" shall each include "activation" and "activate".

[0150] The terminal device 100 undergoing SCG deactivation satisfies some or all of the following conditions.

[0151] When a message regarding reconfiguration of the RRC connection of the SCG (for example, an RRC reconfiguration message, RRCReconfiguration) is received from the base station device 200, Execute the process No uplink transmission to the SCG side · May process uplink data for the SCG side PDCCH is not monitored (received) in the PSCell. No PUSCH transmission to the SCG side In addition, if the message regarding the reconfiguration of the RRC connection received from the base station device 200 contains a parameter indicating SCG deactivation and also contains a parameter regarding the synchronized reconfiguration of the SCG, the terminal device 100 will not perform random access processing in at least the SCG.

[0152] 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.

[0153] [First embodiment] A first embodiment will be described. A communication system 10 appropriately controls switching from SCG deactivation to SCG (re)activation, or switching from SCG (re)activation to SCG deactivation, in communication between a terminal device 100 and a secondary node (base station device 200). Appropriate control means, for example, control to prevent unnecessary switching in order to achieve power saving, or control to postpone switching timing until a necessary timing.

[0154] <Transition Processing to SCG Deactivation> FIG. 11 is a diagram showing an example of a sequence in which the state of SCG transitions to inactive. The base station device 200 is, for example, a master node in MR-DC. MR-DC in FIG. 11 includes, for example, (NG)EN-DC and NR-DC. Also, on the sequence of FIG. 11, although there is one base station device 200, it may be configured with a plurality of master nodes and secondary nodes. Also, on the sequence of FIG. 11, the message transmitted and received with the base station device 200 may be transmitted and received with either the master node or the secondary node. When the master node executes the process executed by the base station device 200 in FIG. 11, the message transmitted from the terminal device 100 to the secondary node is assumed to be transmitted to the master node via inter-base station communication. Also, the process executed by the base station device 200 may be executed by either the master node or the secondary node. Note that, in order to satisfy the above-described conditions, the terminal device 100 does not transmit a message to the secondary node during SCG deactivation, and further does not receive PDCCH from the secondary node.

[0155] In the sequence of FIG. 11, the terminal device 100 sets SCG (S101) and is in the process of (re)activating SCG. The setting of SCG is performed by the terminal device 100 receiving an RRC reconfiguration message including SCG setting parameters from the base station device 200. The SGC setting parameters include, for example, NR SGC setting parameters.

[0156] The terminal device 100 transmits terminal information notification to the base station device 200 (S102). The terminal information notification is, for example, an RRC message or a parameter included in an RRC message. Also, the terminal information notification may be, for example, UE assistance information in an RRC message or a message with another name.

[0157] 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 power.

[0158] Furthermore, the terminal information notification includes, for example, information indicating whether SCG deactivation (or release of SCG) is necessary. The terminal device 100 determines the necessity according to, for example, the amount of communication (amount of data communication) with the secondary node.

[0159] In addition, the terminal information notification may include information indicating whether or not to execute (wish to execute) immediately SCG synchronized reconfiguration parameters when received during SCG deactivation (when instructed to execute SCG synchronized reconfiguration).

[0160] Furthermore, the terminal information notification may include information indicating that, for example, when UL data occurs, SCG reactivation is to be performed (or desired to be performed) without permission from the base station device 200 (without transmitting an SCG reactivation request in process S110 described below). This makes it possible to omit some of the messages between the base station device 200 and the terminal device 100 in SCG reactivation.

[0161] When the base station device 200 receives the terminal information notification (S102), it performs an SCG deactivation determination process (S103). Note that the base station device 200 also performs the SCG deactivation determination process S103 when an event occurs that requires (or may require) SCG deactivation, other than when it receives the terminal information notification.

[0162] The SCG deactivation determination process S103 is a process for determining whether or not to perform SCG deactivation on the terminal device 100. In the SCG deactivation determination process S103, the base station device 200 makes a determination, for example, based on 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 with the secondary node is small, for example, when the amount of communication with the secondary node is equal to or less than a predetermined value in a predetermined period of time, or when communication with the secondary node has not occurred for a predetermined period of time.

[0163] In addition, in the SCG deactivation determination process S103, the base station device 200 makes a determination based on, for example, the amount of radio resources that can be allocated to the secondary node. For example, the base station device 200 determines to perform SCG deactivation when the amount of available radio resources of the secondary node is equal to or less than a predetermined value.

[0164] When it is determined in the SCG deactivation determination process S103 that SCG deactivation is to be performed, the base station device 200 transmits an SCG deactivation instruction to the terminal device 100 (S104). The SCG deactivation instruction is a message instructing the terminal device 100 to perform SCG deactivation. The SCG deactivation instruction is, for example, an RRC message or a parameter included in the RRC message. Furthermore, the SCG deactivation instruction may be, for example, an RRC message "SCG deactivation," or a message with another name. Furthermore, the SCG deactivation instruction may be a parameter included in RRCReconfiguration, or a parameter included in RRCReconfiguration, 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. The SCG deactivation instruction may also be a parameter indicating that the SCG of the terminal device 100 is in a deactivated state. The SCG deactivation instruction may also be a parameter such as scg-state.

[0165] The SCG deactivation instruction includes, for example, information indicating whether or not to immediately execute all or part of the SCG synchronized reconfiguration process when the terminal device 100 is instructed to perform synchronized reconfiguration of the SCG during SCG deactivation. If the information indicates that all will be immediately executed, the terminal device 100 immediately executes synchronized reconfiguration of the SCG. If the information indicates that some or all of the process will not be immediately executed, the terminal device 100 executes the part of the synchronized reconfiguration process of the SCG that has not been processed (suspends synchronized reconfiguration), or does not execute some or all of the synchronized reconfiguration process of the SCG (discards some or all of the synchronized reconfiguration instruction (parameters)).

[0166] Furthermore, the SCG deactivation instruction may include information instructing the terminal device 100 to immediately execute part or all of the synchronized SCG resetting process if at least a first condition is not met when the terminal device 100 is instructed to perform synchronized SCG resetting during SCG deactivation. In this case, the terminal device 100 immediately executes synchronized SCG resetting 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 part or all of the synchronized SCG resetting process when later executing SCG reactivation (suspends part or all of the synchronized SCG resetting process), or does not execute part or all of the synchronized SCG resetting process (discards part or all of the synchronized resetting instruction (parameters)).

[0167] The first condition is, for example, that all or some of the following conditions 1 to 4 are satisfied.

[0168] Condition 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.

[0169] Condition 2: Synchronous reconfiguration of the SCG is performed by using the security key of the secondary node (S-KgNB or Changes to the AS security key generated from the secondary node's security key (S-KeNB) or This is due to a change in the security key.

[0170] Condition 3: There is no radio bearer using the master key among the radio bearers to which the SCG RLC bearer is associated.

[0171] Condition 4: All radio bearers associated with the SCG RLC bearer shall use secondary keys.

[0172] A radio bearer that uses a master key may be a radio bearer for which a parameter (keyToUse) indicating whether to use a master key or a secondary key is set to master (or primary), and a radio bearer that uses a secondary key may be a radio bearer for which a parameter (keyToUse) indicating whether to use a master key or a secondary key is set to secondary.

[0173] When at least this first condition is satisfied, the terminal device 100 does not immediately execute part or all of the synchronized reconfiguration process of the SCG, thereby not interfering with communication in the MR-DC (particularly communication using the master node). As a result, the terminal device 100 does not perform unnecessary SCG reactivation, and therefore power consumption can be reduced.

[0174] The SCG deactivation instruction may include, for example, 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. In this case, the terminal device 100 immediately executes synchronized resetting of the SCG regardless of the first condition.

[0175] Furthermore, the SCG deactivation instruction may include information indicating that, when UL data occurs, an instruction is given to execute SCG reactivation without permission from the base station device 200. In this case, the terminal device 100 immediately executes SCG reactivation.

[0176] When the terminal device 100 receives an SCG deactivation instruction (S104), it performs SCG deactivation processing (S105). The SCG deactivation processing S105 is processing for transitioning to SCG deactivation. Note that, by receiving an SCG deactivation instruction, the terminal device 100 may determine that it is necessary to perform the SCG deactivation processing S105, and may perform the SCG deactivation processing (S105). Also, by not receiving an SCG deactivation instruction, the terminal device 100 may determine that it is not necessary to perform the SCG deactivation processing S105, and may not perform the SCG deactivation processing (S105).

[0177] The SCG deactivation process S105 may include any or all of the following processes (1) to (3).

[0178] (1) The SCG is deemed to be deactivated.

[0179] (2) Notify the lower layer that the SCG has been deactivated.

[0180] (3) If the terminal device 100 was in RRC connected mode or RRC inactive mode before receiving the RRC message including the SCG deactivation instruction, trigger an SDU discard to the PDCP entity of SRB3 and / or re-establish the RLC entity of SRB3.

[0181] In the above process (2), the lower layer may be the MAC layer, the RLC layer, or the PDCP layer. Furthermore, the above process (3) may be performed 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.

[0182] 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.

[0183] In addition, if the terminal device 100 receives an RRCReconfiguration that does not include an SCG deactivation instruction, or an RRCConnectionReconfiguration that does not include an SCG deactivation instruction, or an RRCResume that does not include an SCG deactivation instruction during SCG deactivation, it may perform an SCG activation process.

[0184] The SCG activation process may include any or all of the following processes (4) to (5).

[0185] (4) The SCG is deemed to be activated.

[0186] (5) If UE 100 is in the process of SCG deactivation, it notifies the lower layer that the SCG has been activated.

[0187] In the above process (5), the lower layer may be the MAC layer, the RLC layer, or the PDCP layer.

[0188] In the SCG deactivation process S105, the terminal device 100 stops some or all of the timers running for the SCG. The terminal device 100 also resets some or all of the counters set in the SCG. The terminal device 100 also resets the MAC of the SCG. Furthermore, the terminal device 100 performs a second process on all or some of the radio bearers that satisfy at least a second condition. The second condition is, for example, that the bearer is an SCG bearer, or that the bearer is a split bearer, or that the bearer is a split bearer and a primary path is set in the SCG. The second condition may also be, for example, some or all of the radio bearers set in the terminal device 100.

[0189] The timers running for the SCG to be stopped may include a timer for detecting a radio link failure of the SCG. Also, the timers running for the SCG to be stopped may include a timer for a measurement report of the SCG.

[0190] Furthermore, the counters set in the SCG to be reset may include a counter for detecting a wireless link failure of the SCG.

[0191] Furthermore, "performing the second processing on all or some of the 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.

[0192] Furthermore, "performing the second processing on all or some of the 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, and further determines that it is necessary to perform the second processing on this radio bearer, it performs the second processing on this radio bearer.

[0193] The second condition, "being an SCG bearer," means that the radio bearer (of its PDCP) has a parameter (moreThanOneRLC) that means one or more RLCs, or a parameter (moreThanOneRLC) that means the Primary Path. One or both of the parameters (primaryPath) are not set and the RLC of the radio bearer The second condition "bearer is in the SCG." The second condition "being an SCG bearer" may also be "the RLC bearer of the radio bearer exists only in the SCG." The "RLC bearer of the radio bearer" may be an RLC bearer associated with the radio bearer.

[0194] In addition, the second condition "It is a split bearer and the Primary Path is set in the SCG" means that the Primary Path (or a parameter meaning the Primary Path) of the radio bearer (of the PDCP) is set in the SCG (or S It is also acceptable to refer to CG.

[0195] The second process is a process executed for all or some of the radio bearers that satisfy at least the second condition. The second process is a process performed when transitioning to SCG deactivation and all or some of the pre-processing. The second process includes, for example, all or some of the following processes. Hereinafter, all or some of the radio bearers that satisfy at least the second condition may be referred to as second radio bearers.

[0196] Immediately send the data that has not been sent in the PDCP of the second radio bearer (SCG (until the device is deactivated) or discard all In the PDCP of the second radio bearer, if the reordering timer is running, it is stopped and all stored PDCP SDUs are sent to the upper layer in order after header decompression. Send Re-establish the RLC for the second radio bearer The second process may be performed in the following manner or may include the following manner.

[0197] 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.

[0198] In addition, in the process of immediately transmitting data that has not been transmitted in PDCP, for example, in the case of AM DRB or A where the PDCP entity is not suspended, In the case of M DRB, PDCP SDUs for which the lower layer has not confirmed successful transmission, and / or PDCP SDUs for which a sequence number has been assigned but which have not been passed to the lower layer Send U in order.

[0199] In addition, in the process of immediately transmitting data that has not been transmitted 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 and / or sequence numbers for which successful transmission has not been confirmed by the lower layer PDCP SDUs that have been assigned a "" but have not yet been passed to the lower layer are treated as PDCP SDUs that have just been received from the upper layer and are transmitted in the correct order. In this case, the discard timer does not need to be restarted.

[0200] The discard timer may be a timer that is used to discard the corresponding PDCP SDU when it expires.

[0201] An example of an internal operation of a terminal that performs the second process on all or some of the radio bearers that at least satisfy the second condition will be described.

[0202] For example, the RRC of the terminal device 100 sends the second notification to the PDCP of all or some of the radio bearers that are SCG bearers or split bearers. The PDCP may be replaced by a lower layer(s). If the PDCP that received the second notification 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, the PDCP performs the second processing. Do the following.

[0203] Also, for example, the RRC of the terminal device 100 sends a second notification to a second radio bearer. The PDCP may be replaced by a lower layer(s). The PDCP that receives the second notification performs a second process.

[0204] 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, but is not limited to these.

[0205] The second notification may be, for example, a notification including information instructing the discarding of PDCP data, or may be a notification including information instructing the immediate transmission of data that has not yet been transmitted.

[0206] The second notification may also include information indicating that the SCG has been deactivated, such as SCG deactivated or CG UL transmission prohibited (suspended).

[0207] Furthermore, the second notification may include all or part of this information, or may be multiple messages including some of this information.

[0208] This makes it possible to prevent uplink transmissions from occurring due to transmission of 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-establishment of the SCG but does not execute the instruction immediately but executes it later.The terminal device 100 can prevent unnecessary SCG re-activation and reduce power consumption.

[0209] Furthermore, in the SCG deactivation process S105, the RRC of the terminal device 100 transmits the second information to the SDAP associated with the DRB of the second radio bearer.

[0210] The second information is information indicating that UL transmission is not possible for the DRB, such as that UL transmission for the DRB is prohibited (or stopped) or that the cell group to which the DRB is associated is being deactivated.

[0211] The second information may also be transmitted to the SDAP together with all or part of the following information: The second information may also be all or part of the following information:

[0212] -DRB identity of the DRB QoS flow identifier associated with the DRB In addition, "send the second information to the SDAP associated with the DRB among the second radio bearers" may also mean that the terminal device 100 determines whether or not at least the second condition is met for each DRB, and if it determines that at least the second condition is met, sends the second information to the SDAP associated with this DRB.

[0213] Also, "transmit the second information to the SDAP related to the DRB among the second radio bearers." means that the terminal device 100 determines whether each DRB satisfies at least the second condition. If it is determined that at least the second condition is satisfied, and if it is determined that it is necessary to transmit the second information to the SDAP related to this DRB, it may be to transmit the second information to the SDAP related to this DRB.

[0214] Note that the transmission process of the second information may be executed when at least the DRB satisfying the second condition is associated with the SDAP (if SDAP entity associated with this DRB configured). The terminal device 100 determines whether each DRB is associated with the SDAP. If it is determined that it is associated with the SDAP, it may determine whether this DRB satisfies at least the second condition. Also, the terminal device 100 may determine whether each DRB satisfies at least the second condition. If it is determined that at least the second condition is satisfied, it may determine whether this DRB is associated with the SDAP.

[0215] <RRC Reconfiguration Message Reception Processing During SCG Deactivation> FIG. 12 is a diagram showing an example of a sequence in which the terminal device 100 receives an RRC reconfiguration message during SCG deactivation.

[0216] The base station device 200 transmits an RRC reconfiguration message (first message) to the terminal device 100 during SCG deactivation (S106). The RRC reconfiguration message is an RRC message related to the reconfiguration of the RRC connection sent from the base station device 200 to the terminal device 100, and performs establishment, setting, change, release, and synchronized reconfiguration of radio bearers, cell groups, measurement information, etc. The RRC reconfiguration message may be, for example, RRCReconfiguration of the RRC message, or a message with another name.

[0217] 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.

[0218] For example, when an MGC handover becomes necessary, the base station device 200 determines that the setting of the terminal device 100 needs to be changed.

[0219] Furthermore, for example, when it becomes necessary to change a security key, the base station device 200 determines that it becomes necessary to change the settings of the terminal device 100. The base station device 200 determines that it becomes necessary to change the settings of the terminal device 100 when it becomes necessary to re-establish PDCP related to the security key that needs to be changed (using a key generated from that security key).

[0220] Furthermore, for example, when it becomes necessary to change the QoS flow to DRB mapping rule (a rule indicating the correspondence (map) between QoS flows and DRBs), the base station device 200 determines that it becomes necessary to change the settings of the terminal device 100.

[0221] The RRC reconfiguration message includes, for example, the following information:

[0222] Information indicating that synchronized reconfiguration of the SCG is to be performed If the information includes information instructing to perform synchronized reconfiguration of the SCG, information instructing to immediately perform synchronized reconfiguration of the SCG if at least the first condition is not met If the information includes information indicating that synchronized reconfiguration of the SCG is to be performed, and if at least the first condition is met, information indicating that synchronized reconfiguration of the SCG is to be performed at the time of SCG reactivation If the information includes information instructing to perform synchronized reconfiguration of the SCG, if SCG deactivation is in progress, information instructing to immediately perform synchronized reconfiguration of the SCG If the information includes information indicating that synchronized reconfiguration of the SCG is to be performed, the information indicates that synchronized reconfiguration of the SCG is to be performed at the time of SCG reactivation. The first condition is the first condition described in step S103. That is, the first condition is, for example, that all or some of the following conditions 1 to 4 are satisfied.

[0223] Condition 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.

[0224] Condition 2: Synchronous reconfiguration of the SCG is performed by using the security key of the secondary node (S-KgNB or Changes to the AS security key generated from the secondary node's security key (S-KeNB) or This is due to a change in the security key.

[0225] Condition 3: There is no radio bearer using the master key among the radio bearers to which the SCG RLC bearer is associated.

[0226] Condition 4: All radio bearers associated with the SCG RLC bearer shall use secondary keys.

[0227] A radio bearer that uses a master key may be a radio bearer for which a parameter (keyToUse) indicating whether to use a master key or a secondary key is set to master (or primary), and a radio bearer that uses a secondary key may be a radio bearer for which a parameter (keyToUse) indicating whether to use a master key or a secondary key is set to secondary.

[0228] 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).

[0229] 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 SCG synchronization reconfiguration parameters in the RRC reconfiguration message to the terminal device 100.

[0230] For example, the base station device 200 needs to update the security key of the secondary node, but the terminal device 100 is in the process of SCG deactivation and there is no MN on the SCG side. If there are no terminated RLC bearers (associated with the master key), do not include the synchronized reconfiguration parameters of the SCG.

[0231] 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.

[0232] The third condition is, for example, the security key of the secondary node in NR-DC (S-KgNB or S-KeNB) and uses a secondary key. The above radio bearers may be set in the terminal device 100, and may not be released even if the radio bearers perform processing associated with receiving an RRC reconfiguration request.

[0233] The third condition is, for example, that the base station device 200 is It may be a handover.

[0234] The third condition may be, for example, when the base station device 200 performs SCG reactivation.

[0235] 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 using the master key if the terminal device 100 is not in the process of SCG deactivation, and may determine to release all existing SCG RLC bearers associated with radio bearers using the master key.

[0236] In addition, when 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, if the terminal device 100 is undergoing SCG deactivation, the base station device 200 may determine that it is not necessary to release all existing SCG RLC bearers associated with the radio bearer using the master key, and may determine that it is not necessary to release all existing SCG RLC bearers associated with the radio bearer using the master key.

[0237] Furthermore, the base station device 200 may include, in the RRC reconfiguration message, a parameter indicating an instruction to perform synchronized reconfiguration of the SCG and a parameter indicating an instruction to perform SCG deactivation.

[0238] Incidentally, including a synchronized reconfiguration parameter of an SCG may mean including a synchronized reconfiguration parameter in an SCG configuration parameter. Furthermore, a radio bearer using a master key may mean a radio bearer for which a parameter (keyToUse) indicating whether to use a master key or a secondary key is set to master (or primary). Furthermore, a radio bearer using a secondary key may mean a radio bearer for which a parameter (keyToUse) indicating whether to use a master key or a secondary key is set to secondary.

[0239] When the terminal device 100 receives the RRC reconfiguration message (S106), it performs an RRC reconfiguration message reception process during SCG deactivation (S107). In the RRC reconfiguration message reception process during SCG deactivation S107, the terminal device 100 performs processing in accordance with information (parameters) included in the RRC reconfiguration message.

[0240] The RRC reconfiguration message includes, for example, the following parameters:

[0241] - 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) The processing when each parameter is included will be described below.

[0242] <1. When synchronization reset parameters are included> If the received RRC reconfiguration message includes a synchronization-attached reconfiguration parameter, and if a predetermined condition is satisfied, and if the SCG-side radio bearer is suspended, the terminal device 100 resumes UL communication of the suspended SCG-side radio bearer. 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 a predetermined condition is satisfied, and if it is satisfied." Furthermore, the predetermined condition may be, for example, any of the following conditions 1 to 3.

[0243] (Condition 1) Meet all or part of the following conditions: The CellGroupConfig procedure is initiated by the MCG configuration parameters and is not in the process of SCG deactivation. The process was started using SCG configuration parameters. (Condition 2) Meet all or part 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 that the SCG will be reconfigured with synchronization immediately (or does not include a parameter indicating that the SCG will not be reconfigured with synchronization immediately). The procedure is initiated by SCG setting parameters and is not in the process of SCG deactivation. (Condition 3) Meet all or part 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). 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, uplink transmission is prohibited, etc.). When the synchronization-included reconfiguration parameter is included, the terminal device 100 may resume UL communication of the suspended SCG-side radio bearer regardless of whether SCG deactivation is in progress or not.

[0244] Furthermore, when the received RRC reconfiguration message includes reconfiguration parameters with SCG synchronization, the terminal device 100 may perform the following process.

[0245] The terminal device 100 may immediately perform a synchronized reconfiguration process of the SCG. Furthermore, the terminal device 100 does not immediately execute some or all of the processes of the SCG synchronized reconfiguration process, and executes the processes that are not immediately executed at the time of SCG reactivation. The processes that are immediately executed include, for example, MAC reset on the SCG side, and applying the identifier of the new terminal device 100 as the C-RNTI of the Cell Groupe. In addition, the processes executed during SCG reactivation include, for example, random access processing on the SCG side (which may include processing to configure lower layers according to the received parameter (SpCellConfigCommon) that indicates the common SpCell configuration), synchronous reconfiguration, etc. This includes starting a timer to detect a failure of the

[0246] The terminal device 100 may determine whether to immediately perform the SCG synchronized reconfiguration process based on the SCG deactivation instruction in process S104 or a parameter (parameter indicating whether to immediately perform SCG synchronized reconfiguration) included in the RRC reconfiguration message in process S106. For example, the terminal device 100 may immediately perform the SCG synchronized reconfiguration if at least the first condition is not met, and may perform the SCG reactivation if the first condition is met. Furthermore, the terminal device 100 may return to the SCG deactivation state again after performing the above-described process.

[0247] The first condition is the first condition described in step S103. That is, the first condition is, for example, that all or part of the following conditions 1 to 4 are satisfied.

[0248] Condition 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.

[0249] Condition 2: Synchronous reconfiguration of the SCG is performed by using the security key of the secondary node (S-KgNB or Changes to the AS security key generated from the secondary node's security key (S-KeNB) or This is due to a change in the security key.

[0250] Condition 3: There is no radio bearer using the master key among the radio bearers to which the SCG RLC bearer is associated.

[0251] Condition 4: All radio bearers associated with the SCG RLC bearer shall use secondary keys.

[0252] A radio bearer that uses a master key may be a radio bearer for which a parameter (keyToUse) indicating whether to use a master key or a secondary key is set to master (or primary), and a radio bearer that uses a secondary key may be a radio bearer for which a parameter (keyToUse) indicating whether to use a master key or a secondary key is set to secondary.

[0253] <2. When a parameter instructing PDCP re-establishment is included> When 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 all or some of the radio bearers that satisfy at least the second condition, the terminal device 100 may transmit the data after the SCG is reactivated.

[0254] Furthermore, the terminal device 100 may perform PDCP re-establishment of all or some of the radio bearers that satisfy at least the second condition after the SCG is reactivated. In this case, even if the PDCP re-establishment is performed after the SCG is reactivated, the PDCP that receives a PDCP SDU from an upper layer does not perform processing corresponding to the PDCP SDU.

[0255] The second condition may be the second condition in process 105, that is, that it is an SCG bearer, or that it is a split bearer and the primary path is set in the SCG.

[0256] 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.

[0257] In addition, in the process of transmitting data that has not been transmitted in PDCP, the terminal device 100 may, for example, perform the following operation when AM DRB is being performed or when the PDCP entity is suspended. In the case of an AM DRB that has not yet been transmitted, PDCP SDUs for which successful transmission has not been confirmed by the lower layer, and PDCP SDUs for which a sequence number has been assigned but which have not yet been handed over to the lower layer, are transmitted in order.

[0258] Furthermore, in the process of 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, the terminal device 100 regards 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 as PDCP SDUs that have just been received from the upper layer, and transmits them in order. At this time, there is no need to restart the discard timer.

[0259] The discard timer may be a timer that is used to discard the corresponding PDCP SDU when it expires.

[0260] The base station device 200 immediately performs the PDCP re-establishment process for all or part of the radio bearers that satisfy at least the second condition in the RRC re-configuration message of the process S106 ( or what to do after the SCG is reactivated). The terminal device 100 may determine from the parameter whether to immediately perform the re-establishment process for PDCP of all or some of the radio bearers that satisfy at least the second condition, or to perform the re-establishment process after the SCG is reactivated.

[0261] <3. When a parameter indicating the setting of the QoS flow to DRB mapping rule is included> The terminal device 100 determines whether the received RRC reconfiguration message includes a parameter (mappedQoS-FlowToAdd) indicating the setting of a QoS flow to DRB mapping rule. In this case, the following process is performed: The QoS flow to DRB mapping rule indicates, for example, the correspondence between the QoS flow and the DRB.

[0262] For example, when a predetermined condition is satisfied, the terminal device 100 performs end marker processing. 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 satisfied" may be rephrased as "determining whether or not the predetermined condition is satisfied, and if it is satisfied."

[0263] For example, if the mappedQoS-FlowToAdd included in the received RRC reconfiguration message is the first Let it be a parameter for the QoS flow.

[0264] When all or some of the following conditions 1 to 3 are satisfied, the terminal device 100 performs the QoS flow to DRB mapping stored for the first QoS flow. ng rule's DRB (i.e., already stored, corresponding to the first QoS flow) 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 is a DRB that corresponds to the second information received from the RRC of the terminal device 100 in processing S105. Furthermore, even if the terminal device 100 satisfies all or some of the following conditions 1 to 3, it 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 processing S105.

[0265] (Condition 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. (Condition 2) For the first QoS flow, the stored QoS flow to DRB mapping rule is the same as the QoS flow to DRB mapping rule set by the mappedQoS-FlowToAdd included in the received RRC reconfiguration message. e. In other words, the DRB associated with the first QoS flow in 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. (Condition 3) The uplink SDAP header is set in the DRB of the stored QoS flow to DRB mapping rule. 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 is set, the terminal device 100 may perform all or part of the following processing.

[0266] (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 process S105, an end marker control PDU is constructed, mapped to the default DRB, and transmitted to a lower layer.

[0267] (Process 2) If the default DRB is a DRB corresponding to the second information received from the RRC of the terminal device 100 in process S105, all or part of the following is not performed: constructing an end marker control PDU, mapping the constructed end marker control PDU to the default DRB, and transmitting it to the lower layer.

[0268] 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).

[0269] Furthermore, in processing S105, if the second notification has been sent 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. When the PDCP of the terminal device 100 receives the SDAP Control PDU, it discards the received SDAP Control PDU. Alternatively, if the PDCP of the terminal device 100 is a split bearer and the primary path is in the SCG, If so, the SDAP Control PDU may be discarded.

[0270] Depending on the implementation of the base station device 200, the terminal device 100 may not transmit an end marker control PDU to the SCG during SCG deactivation. For example, the base station device 200 may add mappedQoS-FlowToAdd to the RRC reconfiguration message transmitted to the terminal device 100 during SCG deactivation. Furthermore, for example, the base station device 200 may not include the mappedQoS-FlowToAdd in the RRC reconfiguration message that the terminal device 100 transmits to the terminal device 100 during SCG deactivation. If the end marker control PDU is included, the terminal device 100 is set not to transmit the end marker control PDU to the SCG side.

[0271] Also, when the terminal device 100 determines that it cannot perform the processing according to the RRC reconfiguration message received from the base station device 200, it may initiate the procedure for re-establishing the RRC connection or the procedure related to the radio link failure of the SCG to the base station device 200. For example, when the RRC reconfiguration message received by the terminal device 100 from the base station device 200 does not include the synchronized reconfiguration parameter despite meeting the condition of mandatorily including the synchronized reconfiguration parameter, the terminal device 100 determines that it cannot perform the processing according to the received RRC reconfiguration message. Also, for example, when the RRC reconfiguration message received by the terminal device 100 from the base station device 200 causes the transmission of an end marker for the SCG during the SCG deactivation, the terminal device 100 determines that it cannot perform the processing according to the received RRC reconfiguration message.

[0272] FIG. 13 is a diagram showing an example of a sequence of UL data arrival during SCG deactivation. During the SCG deactivation, UL data arrives at the terminal device 100 (S108). The arrival of the UL data indicates that data to be transmitted to the base station device 200 has occurred. For example, it may be that a PDCP SDU arrives (is transmitted) at the PDCP, or a MAC SDU arrives (is transmitted) at the MAC on the SCG side. Yes.

[0273] When the UL data arrives at the terminal device 100 (S108), the terminal device 100 performs UL data transmission processing during SCG deactivation (S109). The UL data transmission processing S109 during SCG deactivation is a process of determining whether to transmit the UL data to the master node or the secondary node and whether to transmit it immediately, and transmitting the UL data at an appropriate timing. Hereinafter, the UL data transmission processing S109 during SCG deactivation will be described 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. AC arrives.

[0274] <1. When a PDCP SDU arrives at the PDCP> In the terminal device 100, for example, in the process S105, when the 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, the terminal device 100 notifies the SCG of the Primary pa If there is a threshold, the terminal device 100 may notify the RRC of the terminal device 100 when it receives a PDCP SDU from an upper layer. On the other hand, if there is a primary path in the MCG in a split bearer, the terminal device 100 may notify the RRC of the terminal device 100 when the amount of transmission data exceeds or is likely to exceed the threshold. Alternatively, the RRC of the terminal device 100 may be notified.

[0275] The RRC of the terminal device 100, which has received notification that UL data has been generated from the PDCP of the terminal device 100, transmits an SCG reactivation request to the base station device 200 (S110). The SCG reactivation request may be a message requesting the performance of SCG reactivation, or a message including parameters requesting the performance of SCG reactivation.

[0276] The SCG reactivation request is, for example, an RRC message. It may be a notification request or a message with another name. .

[0277] <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 reactivation and prepare for transmitting UL data (for example, by executing a random access procedure with respect to a secondary node). For example, if there is synchronized reconfiguration of the SCG that was not immediately performed in processing S107, 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 reactivation after receiving an SCG reactivation instruction from the base station device 200.

[0278] Furthermore, the MAC of the terminal device 100 may perform SCG reactivation 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, for example, in processing S107.

[0279] For example, if the SCG deactivation instruction received in processing S104 includes instructions on what to do when UL data occurs during SCG deactivation (for example, whether or not SCG reactivation can be performed without sending an SCG reactivation request), the terminal device 100 may follow this instruction.

[0280] The base station device 200 determines whether or not SCG reactivation is necessary for the terminal device 100. The base station device 200 determines that SCG reactivation is necessary for the terminal device 100 when, for example, some or all of the following conditions 1 to 3 are met: (Condition 1) An SCG reactivation request is received from the terminal device 100. (Condition 2) DL data to be transmitted via SCG has occurred in the terminal device 100. (Condition 3) The remaining amount of radio resources of the secondary node is sufficient (above the threshold).

[0281] Note that the base station device 200 may determine at any time whether SCG reactivation of the terminal device 100 is necessary if the terminal device 100 is in the process of deactivating SCG.

[0282] When the base station device 200 determines that SCG reactivation is necessary, it transmits (grants) an SCG reactivation instruction instructing the implementation of SCG reactivation to the terminal device 100 (S111). The SCG reactivation instruction is, for example, an RRC message. Also, the SCG reactivation instruction may be, for example, an RRCReconiguration of an RRC message or a message with another name. Also, the SCG reactivation instruction may be an RRCReconiguration that does not include an SCG deactivation instruction.

[0283] When the terminal device 100 receives an SCG reactivation instruction (S111), it performs an SCG reactivation process (S112). The SCG reactivation process S112 is a process in which the terminal device 100 reactivates SCG.

[0284] Note that the RRC of the terminal device 100 may send a third notification to the PDCP that sent the second notification in process S105. The third notification may be a notification indicating that it is an SCG reactivation or a notification indicating that it is the cancellation of SCG deactivation. For example, it may be "SCG has been reactivated", "UL transmission of SCG has been permitted (resumed)", etc. When the PDCP of the terminal device 100 receives the third notification, it resumes UL transmission of SCG.

[0285] <RRC message processing during radio bearer suspension on the SCG side> 15 is a diagram showing an example of a sequence for receiving a first RRC message when at least the SCG-side radio bearer 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 mean, for example, that 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 mean, for example, that the terminal device 100 detects an SCG failure and SCG transmission of the radio bearer is suspended. The radio bearer being suspended may mean, for example, a state including some or all of a state in which no transmission is performed on the radio bearer, a state in which no reception is performed on the radio bearer, and a state in which data processing is not performed in some or all entities configured on the radio bearer. The SCG transmission of the radio bearer being suspended may mean, for example, a state including a state in which no transmission is performed on the radio bearer associated with the SCG.

[0286] Furthermore, the terminal device 100 in which at least the radio bearer on the SCG side is suspended may be in the process of SCG deactivation. Furthermore, the terminal device 100 in which at least the radio bearer on the SCG side is suspended may be in the process of SCG activation.

[0287] Furthermore, the first RRC message may be an RRCResume message when the terminal device 100 is in an RRC inactive mode. In this case, the terminal device 100 may transmit an RRCResumeRequest to the base station device 200 before receiving the first RRC message from the base station device 200. Furthermore, the first RRC message may be an RRCReconfiguration when the terminal device 100 is in an RRC connected mode. Note that the RRCReconfiguration may be included in the RRCReconfiguration message, and this RRCReconfiguration may include an SCG configuration.

[0288] The base station device 200 transmits a first RRC message to the terminal device 100 for which at least the SCG-side radio bearer is suspended (S113). When the base station device 200 determines that the terminal device will resume transmission of the suspended SCG-side radio bearer, the base station device 200 includes the first parameter in the first RRC message but does not include the second parameter, and transmits the first 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 first parameter and the second parameter in the first RRC message and transmits the first RRC message to the terminal device 100.

[0289] Note that the above phrase "resume transmission of the suspended radio bearer on the SCG side" can be rephrased as "resume transmission of the suspended radio bearer on the SCG side and perform random access to the SCG."

[0290] Furthermore, the above phrase "transmission of the radio bearer on the suspended SCG side is not resumed" can be rephrased as "transmission of the radio bearer on the suspended SCG side is not resumed, and random access to the SCG is not performed."

[0291] The terminal device 100 in which at least the SCG-side radio bearer is suspended performs processing in accordance with the first RRC message received from the base station device 200 (S114). When the first RRC message received from the base station device 200 includes the first parameter but not the second 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. When the first RRC message received from the base station device 200 includes the first parameter and the second 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.

[0292] Note that the above phrase "when the first RRC message received from base station device 200 includes the first parameter and does not include the second parameter" may be rephrased as "when the first RRC message received from base station device 200 includes the first parameter and the SCG is not deactivated" or "when the first RRC message received from base station device 200 includes the first parameter and the SCG is activated."

[0293] Furthermore, the above-mentioned "when the first RRC message received from base station device 200 includes the first parameter and the second parameter" may be rephrased as "when the first RRC message received from base station device 200 includes the first parameter and the SCG is deactivated" or "when the first RRC message received from base station device 200 includes the first parameter and the SCG is not activated."

[0294] Note that the above phrase "resume transmission of the suspended radio bearer on the SCG side" can be rephrased as "resume transmission of the suspended radio bearer on the SCG side, and perform random access to the SCG."

[0295] Furthermore, the above phrase "transmission of the radio bearer on the suspended SCG side is not resumed" can be rephrased as "transmission of the radio bearer on the suspended SCG side is not resumed, and random access to the SCG is not performed."

[0296] The above-mentioned first parameter may be a synchronized reset parameter. Also, the above-mentioned first parameter may be a synchronized reset parameter of the SCG.

[0297] Furthermore, the above-mentioned second 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.

[0298] In addition, the above-mentioned process of "resume transmission of the suspended radio bearer on the SCG side" or the process of "not resume transmission of the suspended radio bearer on the SCG side" may be a process performed after performing a synchronous reconfiguration process.

[0299] Furthermore, the above-mentioned process of "resume transmission of the suspended radio bearer on the SCG side" or the process of "not resume transmission of the suspended radio bearer on the 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 set 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.

[0300] Furthermore, the above-mentioned process of "not resuming transmission of the suspended radio bearer on the SCG side" may be a process performed after the SCG deactivation process.

[0301] The radio bearer on the SCG side may be a radio bearer associated with the SCG.

[0302] In addition, the same processing as that for the radio bearer on the SCG side described above may be performed on the BH (Backhaul) RLC channel for the IAB (Integrated Access and Backhaul)-MT (Mobile Termination) on the SCG side. In other words, when it is determined that "transmission of the suspended radio bearer on the SCG side is to be resumed," the BH for the suspended IAB-MT may be performed on the RLC channel for the SCG side. In addition, if it is determined that "transmission of the radio bearer on the suspended SCG side is not to be resumed," SCG transmission on the BH RLC channel for the suspended IAB-MT does not need to be resumed.

[0303] This makes it possible to prevent data transmission during SCG deactivation, thereby reducing power consumption of the terminal device.

[0304] 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 first RRC message contains a synchronized reconfiguration, resume transmission of the suspended radio bearers on the SCG side, regardless of whether the first RRC message contains an SCG deactivation instruction. After the process of resuming transmission of the suspended radio bearer on the SCG side described above, the SCG deactivation process and / or synchronized reconfiguration process are performed.

[0305] [Second embodiment] During SCG deactivation, the terminal device 100 performs RDI (Reflective QoS flow to DRB) in the terminal device 100 SDAP entity. mapping indication) is set to '1', and downlink SDAP Assume that a data PDU is received, and the received downlink SDAP data PDU includes a QoS flow identifier (QFI) for a second QoS flow, and the reception of this downlink SDAP data PDU may occur via a DRB having an RLC bearer associated with the MCG.

[0306] When all or some of the following conditions 1 to 3 are satisfied, the terminal device 100 performs a QoS flow to DRB mapping for the second QoS flow. ng rule's DRB (i.e., already stored, corresponding to the first QoS flow) In the first embodiment, when the DRB of the QoS flow to DRB mapping rule stored for the second QoS flow is a DRB that does not correspond to the second information received from the RRC of the terminal device 100, the terminal device 100 performs end marker processing. Furthermore, even if the terminal device 100 satisfies all or some of the following conditions 1 to 3, it 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.

[0307] (Condition 1) In the process S105 in the first embodiment, the second information is notified to an SDAP to which at least a DRB that satisfies the second condition is associated. (Condition 2) For the first QoS flow, the stored QoS flow to DRB mapping rule 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 newly received QoS flow to DRB mapping rule in the downlink SDAP data PDU has changed from the DRB associated with the stored QoS flow to DRB mapping rule. (Condition 3) The uplink SDAP header is set in the DRB of the stored QoS flow to DRB mapping rule. Furthermore, the terminal device 100 performs a QoS flow to DRB for the second QoS flow. If no mapping rule exists (is not stored) and a default DRB is set, all or part of the following processing may be performed.

[0308] (Process 1) In the first embodiment, if the default DRB is a DRB that does not correspond to the second information received from the RRC of the terminal device 100, an end marker control PDU is constructed, mapped to the default DRB, and transmitted to a lower layer. (Process 2) In the first embodiment, if the default DRB is a DRB corresponding to the second information received from the RRC of the terminal device 100, all or part of the following processes are not performed: constructing an end marker control PDU, mapping the constructed end marker control PDU to the default DRB, and transmitting it to a lower layer. 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).

[0309] 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 reactivation. The terminal device 100 determines not to immediately execute the processes if, for example, some or all of the following conditions are met:

[0310] -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.

[0311] 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 the SCG RLC bearer must use the secondary key. - The base station device has instructed it to be executed during SCG reactivation. This makes it possible to suppress the implementation of SCG reactivation due to the execution of synchronized reconfiguration of the SCG, and to suppress power consumption of the terminal device 100.

[0312] 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 SCG synchronization-based reconfiguration. The base station device 200 determines that it does not want to execute SCG synchronization-based reconfiguration when, for example, some or all of the following conditions are met:

[0313] -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.

[0314] 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 the SCG RLC bearer must use the secondary key. A radio bearer that uses a master key may be a radio bearer for which a parameter (keyToUse) indicating whether to use a master key or a secondary key is set to master (or primary), and a radio bearer that uses a secondary key may be a radio bearer for which a parameter (keyToUse) indicating whether to use a master key or a secondary key is set to secondary.

[0315] This makes it possible to suppress the implementation of SCG reactivation due to the execution of synchronized resetting, and to suppress power consumption of the terminal device 100.

[0316] 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 UL transmission of the SCG.

[0317] This makes it possible to suppress the implementation of SCG reactivation due to the execution of synchronized resetting, and to suppress power consumption of the terminal device 100.

[0318] 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.

[0319] Condition A is that the bearer is an SCG bearer, or that the bearer is a split bearer and the primary path is set to the SCG.

[0320] Process A is a process in which the PDCP entity of the radio bearer that satisfies condition A immediately transmits or discards data that has not been transmitted. Process A may also be a process in which, when a request for re-establishment of the PDCP entity of the radio bearer that satisfies condition A is made, the data that has not been transmitted is not immediately transmitted during the re-establishment of the PDCP entity, but is transmitted at (or after) SCG reactivation. Process A is a process in which the PDCP entity of the radio bearer that satisfies condition A discards an SDAP Control PDU received from an upper layer.

[0321] This makes it possible to suppress the execution of SCG reactivation due to the occurrence of UL transmission, and to suppress power consumption of the terminal device 100.

[0322] Furthermore, when the RRC of the terminal device 100 receives an SCG deactivation instruction from the base station device 200, it notifies the SDAP to which the radio bearer (DRB) that satisfies the condition A is associated of the information A.

[0323] Information A includes information that indicates that UL transmission of the DRB is prohibited (stopped) or that the cell group to which the DRB is associated is in the process of deactivation, and thus UL transmission is not possible in the DRB.

[0324] This makes it possible to suppress the execution of SCG reactivation due to the occurrence of UL transmission, and to suppress power consumption of the terminal device 100.

[0325] 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.

[0326] Furthermore, the base station device 200 may be implemented so as 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 controls so as not to re-associate, with another DRB, a QoS flow that is an SCG bearer or a split bearer and that is associated with a DRB for which a primary path is set in the SCG. Furthermore, the base station device 200 controls so as not to generate an end marker by, for example, performing control such as (re-)associating, before the SCG deactivation instruction in process 104 in the first embodiment or in the SCG deactivation instruction, all or some of the QoS flows associated with a DRB that satisfies at least the second condition, with a DRB that does not satisfy at least the second condition.

[0327] This makes it possible to suppress the execution of SCG reactivation due to the occurrence of UL transmission, and to suppress power consumption of the terminal device 100.

[0328] Furthermore, when UL data occurs (arrives), the terminal device 100 may be instructed (specified) by the base station device 200 whether to issue an SCG reactivation request to the base station device or to perform SCG reactivation spontaneously by the terminal device 100. For example, the terminal device 100 performs the following process.

[0329] 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 that satisfies condition A. Notification A is a notification indicating that SCG deactivation is in progress or that UL transmission on the SCG side is prohibited (suspended). When the PDCP entity of the radio bearer that satisfies condition A receives data from an upper layer, the PDCP entity of the terminal device 100 notifies the RRC of the terminal device 100 that UL data has occurred. The RRC of the terminal device 100 generates an SCG deactivation request and transmits it to the base station device 200. The RRC of the terminal device 100 receives an SCG deactivation request from the base station device 200. Upon receiving the activation message, the PDCP entity of the radio bearer that sent the second notification sends a notification indicating that the SCG has been reactivated or that UL transmission on the SCG side has started (resumed).

[0330] Alternatively, when UL data occurs in the MAC, the terminal device 100 executes a random access procedure to enable UL transmission. If there is synchronized reconfiguration of the SCG that was not executed immediately, the terminal device 100 executes it in advance.

[0331] This allows the terminal device 100 to perform appropriate processing when UL 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 UL transmission has occurred on the RLC bearer on the SCG side during SCG deactivation, and to perform SCG reactivation autonomously or in response to an instruction from the base station device 200.

[0332] [Other embodiments] The embodiments may be combined with each other. Furthermore, the messages in the sequence do not need to be executed in the correct order, and the order may be reversed. Furthermore, some of the messages in the sequence may not be executed. For example, the processing during SCG deactivation in the terminal device 100 may be performed as long as the terminal device 100 is in the process of SCG deactivation, and the messages in the sequence may be omitted.

[0333] 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.

[0334] 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.

[0335] In each embodiment, "A may be replaced with B" may mean replacing B with A in addition to replacing A with B.

[0336] In addition, in each embodiment, if condition "A" and condition "B" are contradictory conditions, condition "B" may be expressed as an "other" condition of condition "A."

[0337] To summarize, the following is the case.

[0338] A first wireless communication device (base station device) includes a second transmission unit that transmits a message to a second wireless communication device (terminal device), and a second processing unit, wherein when a first wireless bearer of the second wireless communication device is in a suspended state, if the second wireless communication device resumes secondary cell group transmission for the first wireless bearer, the second processing unit includes a first parameter but does not include a second parameter in a first RRC message to be sent to the second wireless communication device, and when the second wireless communication device does not resume secondary cell group transmission for the first wireless bearer, the second processing unit includes the first parameter and the second parameter in the first RRC message to be sent to the second wireless communication device.

[0339] The first parameter is a synchronized reconfiguration parameter for a secondary cell group, and the second parameter is a parameter indicating that the SCG is in a deactivated state.

[0340] The first radio bearer is a radio bearer associated with a secondary cell group.

[0341] The first RRC message is an RRC resumption message or an RRC reconfiguration message.

[0342] A second wireless communication device (terminal device) includes a receiving unit that receives messages from a first wireless communication device, and a processing unit, wherein when a first wireless bearer of the second wireless communication device is in a suspended state, if a first RRC message received from the first wireless communication device includes a first parameter and a second parameter, the processing unit does not resume secondary cell group transmission for the first wireless bearer, and if the first RRC message includes the first parameter but does not include the second parameter, the processing unit resumes secondary cell group transmission for the first wireless bearer.

[0343] The first parameter is a synchronized reconfiguration parameter for a secondary cell group, and the second parameter is a parameter indicating that the SCG is in a deactivated state.

[0344] The first radio bearer is a radio bearer associated with a secondary cell group.

[0345] The first RRC message is an RRC resumption message or an RRC reconfiguration message.

[0346] Note that, although an example of a device has been described in each embodiment, the method of the present disclosure is not limited to this and can be applied to other electronic 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 appliances.

[0347] In addition, in each embodiment, E-UTRA and NR are used as radio access technologies, and EPC and 5GC are used as core networks, but the application of the method of the present disclosure is not limited to these examples. For example, the method of the present disclosure may be applied to radio access technologies and networks of different generations, such as 6th generation and 7th generation.

[0348] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications can be made.

[0349] Furthermore, although each embodiment has been described in detail with reference to the drawings, the specific configuration is not limited to each embodiment. [Explanation of symbols]

[0350] 10: Communication Systems 100: Terminal device 110:CPU 120: Storage 121: Wireless communication program 122: Terminal program 130: Memory 140: Wireless communication circuit 200:Base station equipment 210:CPU 220: Storage 221: Wireless communication program 222: Base station program 230: Memory 240: Wireless communication circuit 250: Network interface 300: Core Network

Claims

1. a receiving unit that receives an RRC (Radio Resource Control) message from the first wireless communication device; a control unit that, when the RRC message includes a first parameter and a second parameter, controls to perform processing according to the second parameter; the second parameter is a parameter indicating an instruction to deactivate the SCG, The control unit controls the radio bearer to resume the suspended radio bearer and then to perform a process according to the second parameter. A second wireless communication device.

2. the first parameter is a synchronized reconfiguration parameter for a secondary cell group; The second wireless communication device according to claim 1 .

3. the radio bearer is a radio bearer associated with a secondary cell group; The second wireless communication device according to claim 1 .

4. The RRC message is an RRC resumption message or an RRC reconfiguration message. The second wireless communication device according to claim 1 .

5. the radio bearer is a data radio bearer. The second wireless communication device according to claim 1 .

6. a transmitter that transmits a radio resource control (RRC) message to the second wireless communication device; a control unit that controls the second wireless communication device to perform processing according to the second parameter by controlling the RRC message to include a first parameter and a second parameter, The second parameter is a parameter indicating that the SCG is in a deactivated state, The control unit controls the second wireless communication device to perform a process according to the second parameter after performing a process to resume the suspended wireless bearer. A first wireless communication device.

7. The first parameter is a synchronized reconfiguration parameter for a secondary cell group. The first wireless communication device according to claim 6 .

8. the radio bearer is a radio bearer associated with a secondary cell group; The first wireless communication device according to claim 6 .

9. The RRC message is an RRC resumption message or an RRC reconfiguration message. The first wireless communication device according to claim 6 .

10. the radio bearer is a data radio bearer. The first wireless communication device according to claim 6 .

11. a first wireless communication device that transmits a radio resource control (RRC) message; a second wireless communication device that receives the RRC message, and when some or all of the configured radio bearers are in a suspended state and the RRC message includes a first parameter and a second parameter, controls the second wireless communication device to perform a process of resuming the suspended radio bearers and then perform a process according to the second parameter; and The second parameter is a parameter indicating an instruction to deactivate the SCG. Wireless communication system.

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