Terminal device, method, and integrated circuit

Abstract

A terminal device that communicates with a base station device is provided with an RRC processing unit that performs RRC processing when a serving cell change to a candidate cell is instructed from a lower layer (first layer / second layer) of a certain cell group. The RRC processing unit determines whether or not to reestablish the RLC entity when the serving cell is changed on the basis of the settings of the candidate cell stored in the RRC processing unit, reestablishes the RLC entity when it is determined that the RLC entity is reestablished when the serving cell is changed, and reestablishes the RLC entity when it is determined that the RLC entity is not reestablished when the serving cell is changed. The RRC processing unit does not reestablish the RLC entity.

Description

Technical Field

[0001] The present invention relates to a terminal device, a method and an integrated circuit. This application claims priority to Japanese Patent Application No. 2022-144347 filed in Japan on September 12, 2022, and the contents are incorporated herein by reference. Background Art

[0002] In the 3rd Generation Partnership Project (3GPP), which is a standardization program for cellular mobile communication systems, technical research and standardization of cellular mobile communication systems including radio access, core network, services, etc. are conducted.

[0003] For example, 3GPP has started technical research and standardization of E-UTRA (Evolved Universal Terrestrial Radio Access) as a radio access technology (Radio Access Technology: RAT) for cellular mobile communication systems for 3.9 and 4 generations. Currently, 3GPP is also conducting technical research and standardization of extended technologies for E-UTRA. It should be noted that E-UTRA is also called Long Term Evolution (LTE: registered trademark, Long Term Evolution), and sometimes the extended technology is also called LTE-Advanced (LTE-A) and LTE-Advanced Pro (LTE-A Pro).

[0004] In addition, 3GPP has started technical research and standardization of NR (New Radio or NR Radio access) as a radio access technology (Radio Access Technology: RAT) for cellular mobile communication systems for the 5th Generation (5G). Currently, 3GPP is also conducting technical research and standardization of NR extension technologies. Prior art literature Non-patent literature

[0005] Non-patent document 1: 3GPP TS 38.300v16.4.0, “NR; NR and NG-RAN Overall description; Stage 2” pp10-134 Non-patent document 2: 3GPP TS 36.300v16.4.0, "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2" pp19-362 Non-patent document 3: 3GPP TS 38.331v16.3.1, "NR; Radio Resource Control (RRC); Protocol specifications" pp21-881 Non-patent document 4: 3GPP TS 36.331 v16.3.0, “Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specifications” pp25-1015 Non-patent document 5: 3GPP TS 37.340 v16.4.0, “Evolved Universal Terrestrial Radio Access (E-UTRA) and NR; Multi-Connectivity; Stage 2” pp7-77 Non-patent document 6: 3GPP TS 38.321v16.3.0, "NR; Medium Access Control (MAC) protocol specification" pp8-152 Non-patent document 7: 3GPP TS 38.331v17.0.0, “NR; Radio Resource Control (RRC) protocol specification” Non-patent document 8: 3GPP TS 38.321v17.0.0, “NR; Medium Access Control (MAC) protocol specification” Summary of the invention Problem that the invention aims to solve

[0006] As an extension technology of NR, there is a service cell change technology for a terminal device to move from the coverage area of ​​a certain cell to the coverage area of ​​another cell. The service cell change is triggered by the measurement of the third layer (also called RRC), and the synchronization reconfiguration for the service cell change is triggered by RRC signaling. Compared with RRC signaling, the signaling of the first or second layer has the advantages of low latency and low overhead. Therefore, research on the service cell change technology triggered by the signaling of the first or second layer (first layer / second layer mobility optimization (L1 / L2mobilityenhancement) technology) has begun.

[0007] Non-patent document 7 is a specification of RRC before the research on layer 1 / layer 2 mobility optimization technology started. However, there is a problem that when the serving cell change is triggered by layer 1 or layer 2 signaling, unnecessary delay occurs due to some processing.

[0008] An aspect of the present invention has been made in view of the above-mentioned situation, and one of its objects is to provide a terminal device, a base station device, a communication method, and an integrated circuit that can efficiently perform communication control. Technical Solution

[0009] In order to achieve the above-mentioned purpose, one scheme of the present invention adopts the following scheme. That is, one scheme of the present invention is a terminal device that communicates with a base station device, wherein the terminal device has an RRC processing unit, and when a service cell change to a candidate cell is indicated from a lower layer (first layer / second layer) of a certain cell group, the RRC processing unit determines whether to re-establish an RLC entity when the service cell is changed based on the setting of the candidate cell stored by the RRC processing unit, and when it is determined that the RLC entity is to be re-established when the service cell is changed, the RRC processing unit re-establishes the RLC entity, and when it is determined that the RLC entity is not to be re-established when the service cell is changed, the RRC processing unit does not re-establish the RLC entity.

[0010] In addition, one embodiment of the present invention is a method for a terminal device communicating with a base station device, the method comprising the following steps: when a service cell change to a candidate cell is indicated from a lower layer (first layer / second layer) of a certain cell group, an RRC entity of the terminal device determines whether to re-establish an RLC entity when the service cell is changed based on the settings of the candidate cell stored by the RRC entity; when it is determined that the RLC entity is to be re-established when the service cell is changed, the RRC entity re-establishes the RLC entity; and when it is determined that the RLC entity is not to be re-established when the service cell is changed, the RRC entity does not re-establish the RLC entity.

[0011] In addition, one embodiment of the present invention is an integrated circuit installed in a terminal device that communicates with a base station device, and the integrated circuit performs the following functions: when a service cell change to a candidate cell is indicated from a lower layer (first layer / second layer) of a certain cell group, the RRC entity of the terminal device determines whether to re-establish an RLC entity when the service cell is changed based on the settings of the candidate cell stored by the RRC entity; when it is determined that the RLC entity is to be re-established when the service cell is changed, the RRC entity re-establishes the RLC entity; and when it is determined that the RLC entity is not to be re-established when the service cell is changed, the RRC entity does not re-establish the RLC entity.

[0012] It should be noted that these inclusive or specific solutions can be implemented through systems, devices, methods, integrated circuits, computer programs or recording media, or through any combination of systems, devices, methods, integrated circuits, computer programs and recording media. Beneficial Effects

[0013] According to one aspect of the present invention, a terminal device, a method, and an integrated circuit can implement efficient communication control processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the communication system according to this embodiment. Figure 2 This is a diagram showing an example of the E-UTRA protocol configuration according to this embodiment. Figure 3 This is a diagram showing an example of the NR protocol configuration of this embodiment. Figure 4 This is a diagram showing an example of the flow of procedures for various settings in RRC according to the present embodiment. Figure 5 This is a block diagram showing the configuration of a terminal device according to this embodiment. Figure 6 It is a block diagram showing the configuration of a base station apparatus according to this embodiment. Figure 7 This is an example of an ASN.1 representation included in a message related to RRC connection re-establishment in NR of this embodiment. Figure 8 This is an example of an ASN.1 expression included in a message related to RRC connection re-establishment in E-UTRA according to the present embodiment. Fig. 9 This is an example of the ASN.1 expression included in the serving cell common setting of this embodiment. Fig.10 This is an example of processing performed by the terminal device in this embodiment. DETAILED DESCRIPTION

[0015] Hereinafter, this embodiment will be described in detail with reference to the drawings.

[0016] LTE (as well as LTE-A, LTE-A Pro) and NR can be defined as different radio access technologies (Radio Access Technology: RAT). In addition, NR can also be defined as a technology included in LTE. In addition, LTE can also be defined as a technology included in NR. In addition, LTE that can be connected to NR through multi-radio dual connectivity (Multi-Radio Dual Connectivity: MR-DC) can be distinguished from existing LTE. In addition, LTE using 5GC in the core network (Core Network: CN) can be distinguished from existing LTE using EPC in the core network. It should be noted that the existing LTE may refer to LTE that does not implement technologies standardized after Release 15 of 3GPP. This embodiment can be applied to NR, LTE, and other RATs. In the following description, terms associated with LTE and NR are used for description, but this embodiment can also be applied to other technologies using other terms. In addition, in this embodiment, the term E-UTRA can be replaced with the term LTE, and the term LTE can be replaced with the term E-UTRA.

[0017] It should be noted that in this embodiment, the name of each node or entity and the processing in each node or entity are described when the radio access technology is E-UTRA or NR, but this embodiment can be used for other radio access technologies. The name of each node or entity in this embodiment can be other names.

[0018] Figure 1 is a schematic diagram of the communication system of this embodiment. Figure 1 The functions of each node, wireless access technology, core network, interface, etc. described are part of the functions closely related to this embodiment and may have other functions.

[0019] E-UTRA100 may be a radio access technology. In addition, E-UTRA100 may be an air interface between UE122 and eNB102. The air interface between UE122 and eNB102 may be referred to as a Uu interface. eNB (E-UTRANNode B: E-UTRAN Node B) 102 may be a base station device of E-UTRA100. eNB102 may have an E-UTRA protocol described later. The E-UTRA protocol may be composed of an E-UTRA user plane (User Plane: UP) protocol described later and an E-UTRA control plane (Control Plane: CP) protocol described later. For UE122, eNB102 may terminate the E-UTRA user plane (UserPlane: UP) protocol and the E-UTRA control plane (Control Plane: CP) protocol. The radio access network composed of eNBs may also be referred to as E-UTRAN.

[0020] EPC (Evolved Packet Core) 104 may be a core network. Interface 112 is an interface between eNB 102 and EPC 104, and may be referred to as an S1 interface. Interface 112 may include a control plane interface for control signals to pass through and / or a user plane interface for user data to pass through. The control plane interface of interface 112 may terminate at a mobility management entity (Mobility Management Entity: MME, not shown) within EPC 104. The user plane interface of interface 112 may terminate at a service gateway (S-GW, not shown) within EPC 104. The control plane interface of interface 112 may be referred to as an S1-MME interface. The user plane interface of interface 112 may be referred to as an S1-U interface.

[0021] It should be noted that one or more eNBs 102 may be connected to the EPC 104 via the interface 112. An interface (not shown) may exist between the multiple eNBs 102 connected to the EPC 104. The interface between the multiple eNBs 102 connected to the EPC 104 may be called an X2 interface.

[0022] NR106 can be a radio access technology. In addition, NR106 can be an air interface between UE122 and gNB108. The air interface between UE122 and gNB108 can be called a Uu interface. gNB (g Node B: g node B) 108 can be a base station device of NR106. gNB108 can have the NR protocol described later. The NR protocol can be composed of the NR user plane (User Plane: UP) protocol described later and the NR control plane (Control Plane: CP) protocol described later. For UE122, gNB108 can terminate the NR user plane (User Plane: UP) protocol and the NR control plane (Control Plane: CP) protocol.

[0023] 5GC110 can be a core network. Interface 116 is an interface between gNB108 and 5GC110, which can be called an NG interface. Interface 116 may contain a control plane interface for control signals to pass through and / or a user plane interface for user data to pass through. The control plane interface of interface 116 can terminate at the access and mobility management function (Accessand mobility Management Function: AMF, not shown) within 5GC110. The user plane interface of interface 116 can terminate at the user plane function (User Plane Function: UPF, not shown) within 5GC110. The control plane interface of interface 116 can be called an NG-C interface. The user plane interface of interface 116 can be called an NG-U interface.

[0024] It should be noted that one or more gNBs 108 may be connected to 5GC 110 via interface 116. An interface (not shown) may exist between multiple gNBs 108 connected to 5GC 110. The interface between multiple gNBs 108 connected to 5GC 110 may be referred to as an Xn interface.

[0025] eNB102 may have a function of connecting to 5GC110. eNB102 having a function of connecting to 5GC110 may be referred to as ng-eNB. Interface 114 is an interface between eNB102 and 5GC110, and may be referred to as an NG interface. Interface 114 may include a control plane interface for control signals to pass through and / or a user plane interface for user data to pass through. The control plane interface of interface 114 may terminate at the AMF within 5GC110. The user plane interface of interface 114 may terminate at the UPF within 5GC110. The control plane interface of interface 114 may be referred to as an NG-C interface. The user plane interface of interface 114 may be referred to as an NG-U interface. A radio access network composed of ng-eNB or gNB may also be referred to as NG-RAN. NG-RAN, E-UTRAN, etc. may also be referred to as a network. In addition, a network may include eNB, ng-eNB, gNB, etc.

[0026] It should be noted that one or more eNBs 102 may be connected to 5GC 110 via interface 114. An interface (not shown) may exist between multiple eNBs 102 connected to 5GC 110. The interface between multiple eNBs 102 connected to 5GC 110 may be referred to as an Xn interface. In addition, the eNB 102 connected to 5GC 110 and the gNB 108 connected to 5GC 110 may be connected via interface 120. The interface 120 between the eNB 102 connected to 5GC 110 and the gNB 108 connected to 5GC 110 may be referred to as an Xn interface.

[0027] gNB108 may have a function of connecting to EPC104. gNB108 having a function of connecting to EPC104 may be referred to as en-gNB. Interface 118 is an interface between gNB108 and EPC104, and may be referred to as an S1 interface. There may be a user plane interface in interface 118 for user data to pass through. The user plane interface of interface 118 may terminate at an S-GW (not shown) within EPC104. The user plane interface of interface 118 may be referred to as an S1-U interface. In addition, eNB102 connected to EPC104 and gNB108 connected to EPC104 may be connected via interface 120. Interface 120 between eNB102 connected to EPC104 and gNB108 connected to EPC104 may be referred to as an X2 interface.

[0028] Interface 124 is an interface between EPC 104 and 5GC 110, and may be an interface through CP only, UP only, or both CP and UP. In addition, depending on the communication system provided by a communication operator, some or all of interfaces 114, 116, 118, 120, and 124 may not exist.

[0029] UE122 may be a terminal device that can receive system information and paging messages sent from eNB102 and / or gNB108. In addition, UE122 may be a terminal device that can establish a wireless connection with eNB102 and / or gNB108. In addition, UE122 may be a terminal device that can establish a wireless connection with eNB102 and a wireless connection with gNB108 at the same time. UE122 may have an E-UTRA protocol and / or an NR protocol. It should be noted that a wireless connection may refer to a Radio Resource Control (RRC) connection.

[0030] In addition, UE122 can be a terminal device that can connect to EPC104 and / or 5GC110 via eNB102 and / or gNB108. When the connection destination core network of eNB102 and / or gNB108 with which UE122 communicates is EPC104, each data radio bearer (DRB: Data Radio Bearer) established between UE122 and eNB102 and / or gNB108 described later can be further uniquely associated with each EPS (Evolved Packet System: Evolved Packet System) bearer via EPC104. Each EPS bearer can be identified by an EPS bearer identifier (Identity or ID). In addition, the same QoS (Quality of Service) can be guaranteed for data such as IP packets, Ethernet (registered trademark) frames, etc. carried by the same EPS bearer.

[0031] In addition, when the connection destination core network of eNB102 and / or gNB108 with which UE122 communicates is 5GC110, each DRB established between UE122 and eNB102 and / or gNB108 can be further associated with one of the PDU (Packet Data Unit) sessions established in 5GC110. One or more QoS flows may exist in each PDU session. Each DRB may be mapped to one or more QoS flows, or may not be mapped to any QoS flow. Each PDU session may be identified by a PDU session identifier (Identity or ID). In addition, each QoS flow may be identified by a QoS flow identifier (Identity or ID). In addition, the same QoS can be guaranteed for data such as IP packets, Ethernet frames, etc. passing through the same QoS flow.

[0032] There may be no PDU session and / or QoS flow in EPC104. In addition, there may be no EPS bearer in 5GC110. When UE122 is connected to EPC104, UE122 has information of EPS bearer, but may not have information in PDU session and / or QoS flow. In addition, when UE122 is connected to 5GC110, UE122 has information in PDU session and / or QoS flow, but may not have information in EPS bearer.

[0033] It should be noted that in the following description, eNB102 and / or gNB108 are also referred to as base station devices, and UE122 is also referred to as terminal devices or UE.

[0034] Figure 2 is a diagram showing an example of the E-UTRA protocol architecture of this embodiment. Figure 3 is a diagram of an example of the NR protocol configuration of this embodiment. Figure 2 and / or Figure 3 The functions of each protocol described are part of the functions closely related to this embodiment, and may have other functions. It should be noted that in this embodiment, uplink (UL) may refer to a link from a terminal device to a base station device. In addition, in this embodiment, downlink (DL) may refer to a link from a base station device to a terminal device.

[0035] Figure 2 (A) is a diagram of the E-UTRA user plane (UP) protocol stack. Figure 2 As shown in (A) of FIG. 1 , the E-UTRA UP protocol may be a protocol between UE 122 and eNB 102. That is, the E-UTRA UP protocol may be a protocol terminated at eNB 102 on the network side. Figure 2 As shown in (A), the E-UTRA user plane protocol stack can be composed of a PHY (Physical layer) 200 as a radio physical layer (Radio Physical layer), a MAC (Medium Access Control) 202 as a medium access control layer (Medium Access Control layer), an RLC (Radio Link Control) 204 as a radio link control layer (Radio Link Control layer), and a PDCP (Packet Data Convergence Protocol) 206 as a packet data convergence protocol layer (Packet Data Convergence Protocol layer).

[0036] Figure 3 (A) is a diagram of the NR user plane (UP) protocol stack. Figure 3 As shown in (A), the NR UP protocol may be a protocol between UE 122 and gNB 108. That is, the NR UP protocol may be a protocol terminated at gNB 108 on the network side. Figure 3 As shown in (A), the NR user plane protocol stack can be composed of PHY300 as the wireless physical layer, MAC302 as the media access control layer, RLC304 as the radio link control layer, PDCP306 as the packet data convergence protocol layer, and SDAP (Service Data Adaptation Protocol) 310 as the service data adaptation protocol layer (Service Data Adaptation Protocol layer).

[0037] Figure 2 (B) is a diagram of the E-UTRA control plane (CP) protocol structure. Figure 2 As shown in (B), in the E-UTRA CP protocol, RRC (Radio Resource Control) 208 as a radio resource control layer (Radio Resource Control layer) may be a protocol between UE 122 and eNB 102. That is, RRC 208 may be a protocol terminated at eNB 102 on the network side. In addition, in the E-UTRA CP protocol, NAS (Non Access Stratum: Non-Access Stratum) 210 as a non-AS (Access Stratum: Access Stratum) layer (non-AS layer) may be a protocol between UE 122 and MME. That is, NAS 210 may be a protocol terminated at MME on the network side.

[0038] Figure 3 (B) is a diagram of the NR control plane (CP) protocol. Figure 3 As shown in (B), in the NR CP protocol, RRC308 as a radio resource control layer may be a protocol between UE122 and gNB108. That is, RRC308 may be a protocol terminated at gNB108 on the network side. In addition, in the NR CP protocol, NAS312 as a non-AS layer may be a protocol between UE122 and AMF. That is, NAS312 may be a protocol terminated at AMF on the network side.

[0039] It should be noted that the AS (Access Stratum) layer may refer to a layer terminated between the UE 122 and the eNB 102 and / or the gNB 108. That is, the AS layer may refer to a layer including a part or all of PHY 200, MAC 202, RLC 204, PDCP 206, and RRC 208 and / or a layer including a part or all of PHY 300, MAC 302, RLC 304, PDCP 306, SDAP 310, and RRC 308.

[0040] It should be noted that in this embodiment, the terms PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), RRC (RRC layer), and NAS (NAS layer) are sometimes used below without distinguishing between the E-UTRA protocol and the NR protocol. In this case, PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), RRC (RRC layer), and NAS (NAS layer) can be the PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), RRC (RRC layer), and NAS (NAS layer) of the E-UTRA protocol, respectively, or the PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), RRC (RRC layer), and NAS (NAS layer) of the NR protocol. In addition, SDAP (SDAP layer) can be the SDAP (SDAP layer) of the NR protocol.

[0041] In addition, in the present embodiment, when distinguishing between the E-UTRA protocol and the NR protocol, PHY200, MAC202, RLC204, PDCP206, and RRC208 are sometimes referred to as PHY for E-UTRA or PHY for LTE, MAC for E-UTRA or MAC for LTE, RLC for E-UTRA or RLC for LTE, PDCP for E-UTRA or PDCP for LTE, and RRC for E-UTRA or RRC for LTE, respectively. In addition, PHY200, MAC202, RLC204, PDCP206, and RRC208 are sometimes referred to as E-UTRAPHY or LTE PHY, E-UTRA MAC or LTE MAC, E-UTRA RLC or LTE RLC, E-UTRA PDCP or LTE PDCP, and E-UTRA RRC or LTE RRC, respectively. In addition, when distinguishing between the E-UTRA protocol and the NR protocol, PHY300, MAC302, RLC304, PDCP306, and RRC308 are sometimes referred to as NR PHY, NR MAC, NR RLC, NR RLC, and NR RRC, respectively. In addition, PHY300, MAC302, RLC304, PDCP306, and RRC308 are sometimes referred to as NRPHY, NRMAC, NR RLC, NR PDCP, and NR RRC, respectively.

[0042] The entities in the AS layer of E-UTRA and / or NR are described. An entity having part or all of the functions of the MAC layer may be referred to as a MAC entity. An entity having part or all of the functions of the RLC layer may be referred to as an RLC entity. An entity having part or all of the functions of the PDCP layer may be referred to as a PDCP entity. An entity having part or all of the functions of the SDAP layer may be referred to as an SDAP entity. An entity having part or all of the functions of the RRC layer may be referred to as an RRC entity. The MAC entity, RLC entity, PDCP entity, SDAP entity, and RRC entity may be referred to as MAC, RLC, PDCP, SDAP, and RRC, respectively.

[0043] It should be noted that the data provided from MAC, RLC, PDCP, SDAP to the lower layer and / or the data provided from the lower layer to MAC, RLC, PDCP, SDAP can be respectively referred to as MAC PDU (Protocol Data Unit), RLC PDU, PDCP PDU, SDAP PDU. In addition, the data provided from the upper layer to MAC, RLC, PDCP, SDAP and / or the data provided from MAC, RLC, PDCP, SDAP to the upper layer can be respectively referred to as MAC SDU (Service Data Unit), RLC SDU, PDCP SDU, SDAP SDU. In addition, the segmented RLC SDU can be referred to as an RLC SDU segment.

[0044] Here, the base station device and the terminal device exchange (transmit and receive) signals in the upper layer (upper layer: higher layer). For example, the base station device and the terminal device can transmit and receive RRC messages (also called RRC message, RRC information: RRC information, RRC signalling: RRC signaling) in the radio resource control (RRC: Radio Resource Control) layer. In addition, the base station device and the terminal device can also transmit and receive MAC control elements in the MAC (Medium Access Control) layer. In addition, the RRC layer of the terminal device obtains system information broadcast from the base station device. Here, RRC messages, system information and / or MAC control elements are also referred to as upper layer signals (upper layer signals: higher layer signaling) or upper layer parameters (upper layer parameters: higher layer parameters). The parameters included in the upper layer signal received by the terminal device can be respectively referred to as upper layer parameters. In the processing of the PHY layer, the upper layer means the upper layer observed from the PHY layer, and therefore, it can also mean one or more of the MAC layer, RRC layer, RLC layer, PDCP layer, NAS (Non Access Stratum) layer, etc. For example, in the processing of the MAC layer, the upper layer may mean one or more of the RRC layer, the RLC layer, the PDCP layer, the NAS layer, and the like. In the following, "A is given (provided) by the upper layer" and "A is given (provided) by the upper layer" may mean that the upper layer of the terminal device (mainly the RRC layer, the MAC layer, etc.) receives A from the base station device, and gives (provides) the received A from the upper layer of the terminal device to the physical layer of the terminal device. For example, in the terminal device, "providing upper layer parameters" may mean that an upper layer signal is received from the base station device, and the upper layer parameters included in the received upper layer signal are provided from the upper layer of the terminal device to the physical layer of the terminal device. Setting upper layer parameters for the terminal device may mean giving (providing) upper layer parameters to the terminal device. For example, setting upper layer parameters for the terminal device may mean that the terminal device receives an upper layer signal from the base station device, and sets the received upper layer parameters in the upper layer. Among them, setting upper layer parameters for the terminal device may include setting default parameters for the upper layer provided in advance to the terminal device. When explaining the transmission of an RRC message from a terminal device to a base station device, the expression "submitting a message to a lower layer" from the RRC entity of the terminal device may be used. In the terminal device, "submitting a message to a lower layer" from the RRC entity may also mean submitting a message to the PDCP layer.Since SRB (Signaling Radio Bearer) (SRB0, SRB1, SRB2, SRB3, etc.) is used to send RRC messages, "submitting a message to the lower layer" from the RRC layer in the terminal device may also mean submitting an RRC message to the PDCP entity corresponding to each SRB. When the RRC entity of the terminal device receives an indication from the lower layer, the lower layer may also mean one or more of the PHY layer, MAC layer, RLC layer, PDCP layer, etc.

[0045] An example of the function of PHY is described. The PHY of the terminal device may have the function of receiving data transmitted via a downlink (Downlink: DL) physical channel (Physical Channel) from the PHY of the base station device. The PHY of the terminal device may have the function of sending data to the PHY of the base station device via an uplink (Uplink: UL) physical channel. The PHY can be connected to the upper MAC through a transport channel (Transport Channel). The PHY can deliver data to the MAC via the transport channel. In addition, the PHY can provide data from the MAC via the transport channel. RNTI (Radio Network Temporary Identifier: Radio Network Temporary Identifier) ​​can be used in the PHY to identify various control information.

[0046] Here, the physical channels are described. The physical channels used for wireless communication between the terminal device and the base station device may include the following physical channels.

[0047] PBCH (Physical Broadcast Channel) PDCCH (Physical Downlink Control Channel) PDSCH (Physical Downlink Shared Channel) PUCCH (Physical Uplink Control Channel) PUSCH (Physical Uplink Shared Channel) PRACH (Physical Random Access Channel)

[0048] PBCH may be used to broadcast system information required by terminal devices.

[0049] In addition, in NR, PBCH can be used to broadcast the time index (SSB-Index) within the period of the block (Synchronization Signal Block: SSB) of the synchronization signal.

[0050] PDCCH can be used to send (or transport) downlink control information (Downlink Control Information: DCI) in downlink wireless communication (wireless communication from a base station device to a terminal device). Here, one or more DCIs (also referred to as DCI formats) can be defined for the transmission of downlink control information. That is, the field for the downlink control information can be defined as DCI and mapped to information bits. PDCCH can be sent in a PDCCH candidate. The terminal device can monitor a set of PDCCH candidates in a serving cell. Monitoring a set of PDCCH candidates may mean attempting to decode the PDCCH according to a certain DCI format. In addition, the terminal device may use CORESET (Control Resource Set: control resource set) to monitor a set of PDCCH candidates. The DCI format can also be used for scheduling PUSCH in a serving cell. PUSCH can be used for sending user data, sending RRC messages described later, and the like.

[0051] PUCCH can be used to send uplink control information (Uplink Control Information: UCI) in uplink wireless communication (wireless communication from a terminal device to a base station device). Here, the uplink control information may include channel state information (CSI: Channel State Information) for indicating the state of a downlink channel. In addition, the uplink control information may also include a scheduling request (SR: Scheduling Request) for requesting UL-SCH (UL-SCH: Uplink Shared CHannel (uplink shared channel)) resources. In addition, the uplink control information may also include HARQ-ACK (Hybrid Automatic Repeat reQuest ACKnowledgement: Hybrid Automatic Repeat Request Acknowledgement).

[0052] The PDSCH can be used to transmit downlink data (DL-SCH: Downlink Shared CHannel) from the MAC layer. In addition, in the case of downlink, the PDSCH can also be used to transmit system information (SI: System Information), random access response (RAR: Random Access Response), etc.

[0053] PUSCH can be used to send uplink data (UL-SCH: Uplink SharedCHannel) from the MAC layer or to send HARQ-ACK and / or CSI together with the uplink data. In addition, PUSCH can also be used to send only CSI or only HARQ-ACK and CSI. That is, PUSCH can also be used to send only UCI. In addition, PDSCH or PUSCH can also be used to send RRC signaling (also called RRC message) and MAC CE. Here, in PDSCH, the RRC signaling sent from the base station device can be signaling shared by multiple terminal devices in the cell. In addition, the RRC signaling sent from the base station device can also be signaling dedicated to a certain terminal device (also called dedicated signaling). That is, terminal device-specific (UE-specific) information can also be sent using signaling dedicated to a certain terminal device. In addition, PUSCH can be used to send UE capabilities (UE Capability) in the uplink.

[0054] PRACH can be used to send a random access preamble. PRACH can be used to indicate the initial connection establishment procedure, the handover procedure, the connection re-establishment procedure, the synchronization (timing adjustment) for uplink transmission, and the request for UL-SCH resources.

[0055] An example of the function of MAC is described. MAC can be called a MAC sublayer (sublayer). MAC can have the function of mapping multiple logical channels (logical channels: Logical Channel) to the corresponding transmission channels. Logical channels can be identified by logical channel identifiers (Logical Channel Identity or Logical Channel ID). MAC can be connected to the upper RLC through logical channels (Logical Channel). Logical channels can be divided into control channels for transmitting control information and service channels for transmitting user information according to the type of information transmitted. In addition, logical channels can be divided into uplink logical channels and downlink logical channels. MAC can have the function of multiplexing MAC SDUs belonging to one or more different logical channels and providing them to PHY. In addition, MAC can also have the function of demultiplexing MAC PDUs provided from PHY and providing them to the upper layer via the logical channels to which each MAC SDU belongs. In addition, MAC can also have the function of performing error correction through HARQ (Hybrid Automatic Repeat reQuest). In addition, MAC can also have the function of reporting scheduling information. MAC may have the function of using dynamic scheduling to perform priority processing between terminal devices. In addition, MAC may also have the function of performing priority processing between logical channels within a terminal device. MAC may also have the function of performing priority processing of overlapping resources within a terminal device. E-UTRA MAC may have the function of identifying Multimedia Broadcast Multicast Services (MBMS). In addition, NR MAC may also have the function of identifying Multicast / Broadcast Service (MBS). MAC may have the function of selecting a transmission format. MAC may have the function of performing discontinuous reception (DRX) and / or discontinuous transmission (DTX), the function of performing a random access (RA) process, the function of a power headroom report (PHR) that notifies information on the transmittable power, the function of a buffer status report (BSR) that notifies information on the amount of data buffered for transmission, and the like.NR MAC may have a bandwidth adaptation (BA) function. In addition, the MAC PDU format used in E-UTRA MAC and the MAC PDU format used in NR MAC may be different. In addition, the MAC PDU may include a MAC control element (MAC Control Element: MAC CE) which is an element for controlling in MAC.

[0056] The following describes logical channels for uplink (UL: Uplink) and / or downlink (DL: Downlink) used in E-UTRA and / or NR.

[0057] BCCH (Broadcast Control Channel) may be a downlink logical channel for broadcasting control information such as system information (SI).

[0058] PCCH (Paging Control Channel) may be a downlink logical channel for transmitting paging messages.

[0059] CCCH (Common Control Channel) can be a logical channel for transmitting control information between a terminal device and a base station device. CCCH can also be used when a terminal device does not have an RRC connection. In addition, CCCH can also be used between a base station device and multiple terminal devices.

[0060] DCCH (Dedicated Control Channel) can be a logical channel used to send dedicated control information in a point-to-point bidirectional manner between a terminal device and a base station device. Dedicated control information can refer to control information dedicated to each terminal device. DCCH can also be used when the terminal device has an RRC connection.

[0061] DTCH (Dedicated Traffic Channel) can be a logical channel for sending user data one-to-one (point-to-point) between a terminal device and a base station device. DTCH can be a logical channel for sending dedicated user data. Dedicated user data can refer to user data dedicated to each terminal device. DTCH can exist in both the uplink and the downlink.

[0062] The mapping of uplink logical channels and transport channels in E-UTRA and / or NR is described.

[0063] The CCCH can be mapped to the UL-SCH (Uplink Shared Channel) which is an uplink transmission channel.

[0064] The DCCH may also be mapped to the UL-SCH (Uplink Shared Channel) which is an uplink transmission channel.

[0065] The DTCH may also be mapped to the UL-SCH (Uplink Shared Channel) which is an uplink transmission channel.

[0066] The mapping of logical channels and transport channels for the downlink in E-UTRA and / or NR is described.

[0067] The BCCH may be mapped to a BCH (Broadcast Channel) and / or a DL-SCH (Downlink Shared Channel) which are downlink transmission channels.

[0068] The PCCH can be mapped to the PCH (Paging Channel) which is a downlink transmission channel.

[0069] The CCCH can be mapped to the DL-SCH (Downlink Shared Channel) which is a downlink transmission channel.

[0070] The DCCH may also be mapped to the DL-SCH (Downlink Shared Channel) which is a downlink transmission channel.

[0071] DTCH can also be mapped to DL-SCH (Downlink Shared Channel) which is a downlink transmission channel.

[0072] An example of the function of RLC is described. RLC may also be referred to as an RLC sublayer (sublayer). E-UTRA RLC may have a function of segmenting (Segmentation) and / or concatenating (Concatenation) the data provided from the upper layer PDCP and providing it to the lower layer (lower layer). E-UTRA RLC may have a function of reassembling (reassembling) and reordering (re-ordering) the data provided from the lower layer and providing it to the upper layer. NR RLC may have a function of attaching a sequence number independent of the sequence number attached in the PDCP to the data provided from the upper layer PDCP. In addition, NR RLC may also have a function of segmenting (Segmentation) the data provided from the PDCP and providing it to the lower layer. In addition, NR RLC may also have a function of reassembling (reassembling) the data provided from the lower layer and providing it to the upper layer. In addition, RLC may have a data retransmission function and / or a retransmission request function (Automatic Repeat reQuest: ARQ). In addition, RLC may also have a function of performing error correction through ARQ. The control information indicating the data that needs to be retransmitted and sent from the receiving side of the RLC to the sending side for ARQ can be called a status report. In addition, the status report sending indication sent from the sending side of the RLC to the receiving side can be called a poll. In addition, the RLC can also have the function of detecting data duplication. In addition, the RLC can also have the function of discarding data. There can be three modes in the RLC: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). Under TM, the data received from the upper layer may not be segmented, and the RLC header may not be attached. The TM RLC entity may be a uni-directional entity, set as a transmitting TM RLC entity or a receiving TM RLC entity. In UM, the data received from the upper layer is segmented and / or concatenated, the RLC header is attached, etc., but the data retransmission control may not be performed. The UM RLC entity may be a uni-directional entity or a bi-directional entity. When the UM RLC entity is a unidirectional entity, the UM RLC entity may be configured as a transmitting UM RLC entity or a receiving UM RLC entity. When the UM RLC entity is a bidirectional entity, the UM RLC entity may be configured as a UM RLC entity consisting of a transmitting side and a receiving side.In AM, segmentation and / or concatenation of data received from the upper layer, attachment of RLC headers, and data retransmission control can be performed. The AM RLC entity can be a bidirectional entity, which is set as an AM RLC consisting of a transmitting side and a receiving side. It should be noted that the data provided to the lower layer and / or the data provided from the lower layer in TM can be called TMD PDU. In addition, the data provided to the lower layer and / or the data provided from the lower layer in UM can be called UMD PDU. In addition, the data provided to the lower layer or the data provided from the lower layer in AM can be called AMD PDU. The RLC PDU format used in E-UTRA RLC and the RLC PDU format used in NR RLC can be different. In addition, the RLC PDU can include RLC PDU for data and RLC PDU for control. The RLC PDU for data can be called RLC DATA PDU (RLC Data PDU, RLC data PDU). In addition, the control RLC PDU can be called RLC CONTROL PDU (RLC Control PDU, RLC control PDU, RLC control PDU).

[0073] An example of the function of PDCP is described. PDCP may also be referred to as a PDCP sublayer (sublayer). PDCP may have a function of maintaining a sequence number. In addition, PDCP may also have a header compression / decompression function for efficiently transmitting user data such as IP packets (IP Packets) and Ethernet frames in a wireless section. The protocol for header compression / decompression of IP packets may be referred to as the ROHC (Robust Header Compression) protocol. In addition, the protocol for Ethernet frame header compression / decompression may be referred to as the EHC (Ethernet (registered trademark) Header Compression: Ethernet Header Compression) protocol. In addition, PDCP may also have a data encryption / decoding function. In addition, PDCP may also have a data integrity protection / integrity verification function. In addition, PDCP may also have a reordering function. In addition, PDCP may also have a PDCP SDU retransmission function. In addition, PDCP may also have a data discarding function using a discard timer. In addition, PDCP may also have a multiplexing function. In addition, PDCP may also have a function of discarding duplicated received data. The PDCP entity can be a bidirectional entity, consisting of a transmitting PDCP entity and a receiving PDCP entity. In addition, the PDCP PDU format used in E-UTRA PDCP and the PDCP PDU format used in NR PDCP may be different. In addition, the PDCP PDU may include a PDCP PDU for data and a PDCP PDU for control. The PDCP PDU for data may be referred to as a PDCP DATA PDU (PDCPData PDU, PDCP data PDU). In addition, the PDCP PDU for control may be referred to as a PDCP CONTROL PDU (PDCPControl PDU, PDCP control PDU, PDCP control PDU).

[0074] An example of the function of SDAP is described. SDAP is the service data adaptation protocol layer. SDAP may have the function of corresponding (mapping: mapping) the QoS flow of the downlink sent from 5GC110 to the terminal device via the base station device and the data radio bearer (DRB) and / or the mapping of the QoS flow of the uplink sent from the terminal device to 5GC110 via the base station device and the DRB. In addition, SDAP may also have the function of storing mapping rule information. In addition, SDAP may also have the function of marking the QoS flow identifier (QoS Flow ID: QFI). It should be noted that there may be SDAP PDU for data and SDAP PDU for control in the SDAP PDU. The SDAP PDU for data may be referred to as SDAP DATA PDU (SDAP Data PDU, SDAP data PDU). In addition, the SDAPPDU for control may be referred to as SDAP CONTROL PDU (SDAP Control PDU, SDAP control PDU, SDAP control PDU). It should be noted that the SDAP entity of the terminal device may exist for one PDU session.

[0075] An example of the functions of RRC is described. RRC may have a broadcast (broadcast: broadcast) function. RRC may have a paging (paging: Paging) function from EPC104 and / or 5GC110. RRC may have a paging (paging: Paging) function from eNB102 connected to gNB108 or 5GC110. In addition, RRC may also have an RRC connection management function. In addition, RRC may also have a radio bearer control function. In addition, RRC may also have a cell group control function. In addition, RRC may also have a mobility control function. In addition, RRC may also have a terminal device measurement report and a terminal device measurement report control function. In addition, RRC may also have a QoS management function. In addition, RRC may also have a radio link failure detection and recovery function. RRC may use RRC messages for broadcasting, paging, RRC connection management, radio bearer control, cell group control, mobility control, terminal device measurement report and terminal device measurement report control, QoS management, detection and recovery of radio link failure, etc. It should be noted that the RRC messages and parameters used in E-UTRA RRC may be different from the RRC messages and parameters used in NR RRC.

[0076] The RRC message can be sent using the BCCH of the logical channel, the PCCH of the logical channel, the CCCH of the logical channel, or the DCCH of the logical channel. In addition, the RRC message sent using the DCCH can also be renamed as dedicated RRC signaling or RRC signaling.

[0077] The RRC message sent using BCCH may include, for example, a Master Information Block (MIB), various types of System Information Blocks (SIB), and other RRC messages. The RRC message sent using PCCH may include, for example, a paging message, and other RRC messages.

[0078] The RRC message sent in the uplink (UL) direction using CCCH may include, for example, an RRC setup request message (RRC Setup Request), and may also include an RRC resume request message (RRC Resume Request), an RRC reestablishment request message (RRC Reestablishment Request), an RRC system information request message (RRC SystemInfo Request), etc. In addition, for example, it may include an RRC connection request message (RRC Connection Request), an RRC connection resume request message (RRC Connection Resume Request), an RRC connection reestablishment request message (RRC Connection Reestablishment Request), etc. In addition, other RRC messages may also be included.

[0079] The RRC message sent in the downlink (DL) direction using CCCH may include, for example, an RRC connection rejection message (RRC Connection Reject), an RRC connection configuration message (RRC Connection Setup), an RRC connection reestablishment message (RRC Connection Reestablishment), an RRC connection reestablishment rejection message (RRC Connection Reestablishment Reject), etc. In addition, for example, an RRC rejection message (RRC Reject), an RRC configuration message (RRC Setup), etc. In addition, other RRC messages may also be included.

[0080] The RRC signaling sent in the uplink (UL) direction using the DCCH may include, for example, a measurement report message (Measurement Report), an RRC connection reconfiguration complete message (RRC Connection ReconfigurationComplete), an RRC connection configuration complete message (RRC Connection Setup Complete), an RRC connection reestablishment complete message (RRC Connection Reestablishment Complete), a security mode complete message (Security Mode Complete), a UE capability information message (UE Capability Information), etc. In addition, for example, a measurement report message (Measurement Report), an RRC reconfiguration complete message (RRC ReconfigurationComplete), an RRC configuration complete message (RRC Setup Complete), an RRC reestablishment complete message (RRC Reestablishment Complete), an RRC resume complete message (RRC Resume Complete), a security mode complete message (Security Mode Complete), a UE capability information message (UE Capability Information), etc. In addition, other RRC signaling may also be included.

[0081] The RRC signaling sent in the downlink (DL) direction using the DCCH may include, for example, an RRC connection reconfiguration message (RRC Connection Reconfiguration), an RRC connection release message (RRC Connection Release), a security mode command message (Security Mode Command), a UE capability inquiry message (UE Capability Enquiry), etc. In addition, for example, an RRC reconfiguration message (RRC Reconfiguration), an RRC restart message (RRCResume), an RRC release message (RRC Release), an RRC reestablishment message (RRC Reestablishment), a security mode command message (Security Mode Command), a UE capability inquiry message (UE Capability Enquiry), etc. In addition, other RRC signaling may also be included.

[0082] An example of the function of NAS is described below. NAS may have an authentication function. In addition, NAS may also have a function of performing mobility management. In addition, NAS may also have a security control function.

[0083] The functions of PHY, MAC, RLC, PDCP, SDAP, RRC, and NAS are just examples, and some or all of the functions may not be installed. In addition, some or all of the functions of each layer may also be included in other layers.

[0084] Next, the state transition of UE122 in LTE and NR is explained. When UE122 connected to EPC or 5GC has established an RRC connection (RRC connection has been established), UE122 may be in RRC_CONNECTED state. The state in which the RRC connection is established may include a state in which UE122 saves part or all of the UE context described later. In addition, the state in which the RRC connection is established may also include a state in which UE122 can send and / or receive unicast data. In addition, when the RRC connection of UE122 is terminated (suspended), UE122 may be in RRC_INACTIVE state. In addition, UE122 being in RRC_INACTIVE state may be when the RRC connection is terminated when UE122 is connected to 5GC. When UE122 is neither in RRC_CONNECTED state nor in RRC_INACTIVE state, UE122 may be in RRC_IDLE state.

[0085] It should be noted that, when UE122 is connected to EPC, it does not have the RRC_INACTIVE state, but the termination of the RRC connection can be initiated by E-UTRAN. When UE122 is connected to EPC, when the RRC connection is terminated, UE122 can save the UE's AS context and the identifier (resumeIdentity) for resumption (resume) and transition to the RRC_IDLE state. When UE122 saves the UE's AS context, and the resumption of the RRC connection is permitted (Permit) by E-UTRAN, and UE122 needs to transition from the RRC_IDLE state to the RRC_CONNECTED state, the upper layer of the RRC layer of UE122 (e.g., the NAS layer) can start the resumption of the terminated RRC connection.

[0086] The definition of suspension may be different in UE 122 connected to EPC 104 and UE 122 connected to 5GC 110. In addition, all or part of the process of UE 122 recovering from suspension may be different in the case where UE 122 is connected to EPC (the case where UE 122 is suspended in RRC_IDLE state) and the case where UE 122 is connected to 5GC (the case where UE 122 is suspended in RRC_INACTIVE state).

[0087] It should be noted that the RRC_CONNECTED state, RRC_INACTIVE state, and RRC_IDLE state can be respectively referred to as the connected state (connected mode), the disabled state (inactive mode), and the idle state (idle mode), and can also be referred to as the RRC connected state (RRC connected mode), the RRC disabled state (RRC inactive mode), and the RRC idle state (RRC idle mode).

[0088] The AS context of the UE saved by UE122 may include all or part of the current RRC settings, the current security context, the PDCP state including the ROHC (RObust Header Compression) state, the C-RNTI (Cell Radio Network Temporary Identifier) ​​used in the PCell of the connection source (Source), the cell identifier (cellIdentity), and the physical cell identifier of the PCell of the connection source. It should be noted that the AS context of the UE saved by any or all of eNB102 and gNB108 may include the same information as the AS context of the UE saved by UE122, and may also include information different from the information included in the AS context of the UE saved by UE122.

[0089] The security context may refer to all or part of the information including the AS-level key, NH (Next Hop parameter), NCC (Next Hop Chaining Counter parameter) for deriving the next-hop access key, an identifier of the selected AS-level encryption algorithm, and a counter for replay protection.

[0090] Next, the serving cell (Serving Cell) is explained. In a terminal device in which the RRC connection state of CA and / or DC described later is not set, the serving cell may be composed of a primary cell (Primary Cell: PCell). In addition, in a terminal device in which the RRC connection state of CA and / or DC described later is set, multiple serving cells may refer to a set of multiple cells (set of cell(s)) consisting of one or more special cells (Special Cell: SpCell) and one or more secondary cells (Secondary Cell: SCell). SpCell can support PUCCH transmission and contention-based random access (contention-based Random Access: CBRA), and SpCell can be always activated. PCell can be a cell used in the RRC connection establishment process when a terminal device in the RRC idle state is converted to the RRC connected state. In addition, PCell can also be a cell used in the RRC connection re-establishment process when the terminal device re-establishes the RRC connection. In addition, PCell can also be a cell used in the random access process during switching. PSCell can be a cell used for the random access process when adding a secondary node described later. Furthermore, the SpCell may be a cell used for purposes other than those described above.

[0091] The group of serving cells configured for a terminal device is composed of SpCell and one or more SCells, which can be regarded as configuring carrier aggregation (CA) for the terminal device. In addition, for a terminal device configured with CA, a cell that provides additional radio resources to SpCell can be referred to as SCell.

[0092] In the group of service cells set by RRC, for the cells in which the uplink is set, the group of service cells using the same timing reference cell (timing reference cell) and the same timing advance value can be called a timing advance group (Timing Advance Group: TAG). In addition, the TAG of the SpCell including the MAC entity can mean the primary timing advance group (Primary Timing Advance Group: PTAG). In addition, the TAG other than the above-mentioned PTAG can mean the secondary timing advance group (Secondary Timing Advance Group: STAG). It should be noted that one or more of the TAGs can also be composed of each cell group described later.

[0093] The cell group (Cell Group) set from the base station device to the terminal device is described. The cell group can be composed of one SpCell. In addition, the cell group can also be composed of one SpCell and one or more SCells. That is, the cell group can be composed of one SpCell and one or more SCells as needed (optionally). In addition, the cell group can be expressed as a set of cells (set of cell(s)).

[0094] Dual Connectivity (DC) may refer to a technology for performing data communications using wireless resources of a cell group respectively constituted by a first base station device (first node) and a second base station device (second node). In the case of DC and MR-DC described later, a cell group may be added to the terminal device from the base station device. In order to perform DC, the first base station device may add a second base station device. The first base station device may be referred to as a master node (Master Node: MN). In addition, the cell group constituted by the master node may be referred to as a master cell group (Master Cell Group: MCG). The second base station device may be referred to as a secondary node (Secondary Node: SN). In addition, the cell group constituted by the secondary node may be referred to as a secondary cell group (Secondary Cell Group: SCG). It should be noted that the master node and the secondary node may be constituted in the same base station device.

[0095] In addition, when DC is not set, the cell group set in the terminal device can be called MCG. In addition, when DC is not set, the SpCell set in the terminal device can be PCell. In addition, the NR without DC can be called NR independent.

[0096] It should be noted that multi-radio dual connectivity (MR-DC) may refer to a technology for performing DC using E-UTRA in MCG and NR in SCG. In addition, MR-DC may refer to a technology for performing DC using NR in MCG and E-UTRA in SCG. In addition, MR-DC may refer to a technology for performing DC using NR in both MCG and SCG. MR-DC may be a technology included in DC. As an example of MR-DC using E-UTRA in MCG and NR in SCG, there may be EN-DC (E-UTRA-NR Dual Connectivity) using EPC in the core network, and there may be NGEN-DC (NG-RAN E-UTRA-NR Dual Connectivity) using 5GC in the core network. In addition, as an example of MR-DC using NR in MCG and E-UTRA in SCG, there may be NE-DC (NR-E-UTRA Dual Connectivity) using 5GC in the core network. In addition, as an example of MR-DC using NR in both MCG and SCG, there can be NR-DC (NR-NR Dual Connectivity) using 5GC in the core network.

[0097] It should be noted that, in the terminal device, there may be a MAC entity for each cell group. For example, when DC or MR-DC is set for the terminal device, there may be a MAC entity for MCG and a MAC entity for SCG. The MAC entity for MCG in the terminal device can always be established in the terminal device in all states (RRC idle state, RRC connected state, and RRC disabled state, etc.). In addition, when SCG is set in the terminal device, the MAC entity for SCG in the terminal device can be created (create) by the terminal device. In addition, the MAC entity for each cell group of the terminal device can be set by the terminal device receiving RRC signaling from the base station device. When the MAC entity is associated with the MCG, SpCell may mean PCell. In addition, when the MAC entity is associated with the SCG, SpCell may mean the primary SCG cell (Primary SCG Cell: PSCell). In addition, when the MAC entity is not associated with the cell group, SpCell may mean PCell. PCell, PSCell and SCell are serving cells. In EN-DC and NGEN-DC, the MAC entity for MCG may be an E-UTRA MAC entity, and the MAC entity for SCG may be an NR MAC entity. In addition, in NE-DC, the MAC entity for MCG may be an NR MAC entity, and the MAC entity for SCG may be an E-UTRA MAC entity. In addition, in NR-DC, the MAC entities for both MCG and SCG may be NR MAC entities. It should be noted that the existence of one MAC entity for each cell group may be renamed as the existence of one MAC entity for each SpCell. In addition, one MAC entity for each cell group may be renamed as one MAC entity for each SpCell.

[0098] The radio bearer is described. When the terminal device communicates with the base station device, a wireless connection can be established by establishing a radio bearer (RB: Radio Bearer) between the terminal device and the base station device. The radio bearer used for CP can be called a signaling radio bearer (SRB: Signaling Radio Bearer). In addition, the radio bearer used for UP can be called a data radio bearer (DRB: Data Radio Bearer). A radio bearer identifier (Identity: ID) can be assigned to each radio bearer. The radio bearer identifier for SRB can be called an SRB identifier (SRB Identity or SRB ID). The radio bearer identifier for DRB can be called a DRB identifier (DRB Identity or DRB ID). SRB0 to SRB2 can be defined for the SRB of E-UTRA, and SRBs other than these can be defined. SRB0 to SRB3 can be defined for the SRB of NR, and SRBs other than these can be defined. SRB0 can be an SRB for RRC messages sent and / or received using the CCCH of a logical channel. SRB1 can be an SRB used for RRC signaling and for NAS signaling before the establishment of SRB2. The RRC signaling sent and / or received using SRB1 may include piggybacked NAS signaling. The DCCH of the logical channel may be used for all RRC signaling and NAS signaling sent and / or received using SRB1. SRB2 may be an SRB used for NAS signaling and for RRC signaling including logged measurement information. The DCCH of the logical channel may be used for all RRC signaling and NAS signaling sent and / or received using SRB2. In addition, SRB2 may be a lower priority than SRB1. SRB3 may be an SRB used to send and / or receive specific RRC signaling to a terminal device when EN-DC, NGEN-DC, NR-DC, etc. are set. The DCCH of the logical channel may be used for all RRC signaling and NAS signaling sent and / or received using SRB3. In addition, other SRBs may also be prepared for other purposes. DRB may be a radio bearer for user data. The DTCH of the logical channel may be used for RRC signaling sent and / or received using DRB.

[0099] The wireless bearer in the terminal device is described. The wireless bearer may include an RLC bearer. The RLC bearer may be composed of one or two RLC entities and logical channels. When there are two RLC entities in the RLC bearer, the RLC entity may be a TM RLC entity and / or a sending RLC entity and a receiving RLC entity in a unidirectional UM mode RLC entity. SRB0 may be composed of one RLC bearer. The RLC bearer of SRB0 may be composed of an RLC entity and a logical channel of TM. SRB0 may always be established in the terminal device in all states (RRC idle state, RRC connected state, and RRC disabled state, etc.). When the terminal device changes from the RRC idle state to the RRC connected state, an SRB1 may be established and / or set for the terminal device through the RRC signaling received from the base station device. SRB1 may be composed of a PDCP entity and one or more RLC bearers. The RLC bearer of SRB1 may be composed of an RLC entity and a logical channel of AM. An SRB2 can be established and / or set for a terminal device by RRC signaling received from a base station device by a terminal device in an AS-secure RRC connection state. SRB2 can be composed of a PDCP entity and one or more RLC bearers. The RLC bearer of SRB2 can be composed of an RLC entity and a logical channel of AM. It should be noted that the PDCP on the base station device side of SRB1 and SRB2 can be placed in the master node. When adding a secondary node in EN-DC, NGEN-DC, or NR-DC or changing a secondary node, an SRB3 can be established and / or set for a terminal device by RRC signaling received from a base station device by a terminal device in an AS-secure RRC connection state. SRB3 can be a direct SRB between a terminal device and a secondary node. SRB3 can be composed of a PDCP entity and one or more RLC bearers. The RLC bearer of SRB3 can be composed of an RLC entity and a logical channel of AM. The PDCP on the base station device side of SRB3 can be placed in a secondary node. One or more DRBs may be established and / or configured for a terminal device through RRC signaling received from a base station device by a terminal device in an AS-secured RRC connection state. A DRB may consist of a PDCP entity and one or more RLC bearers. The RLC bearer of a DRB may consist of an AM or UM RLC entity and a logical channel.

[0100] It should be noted that, in MR-DC, the radio bearer in which PDCP is placed in the primary node can be called an MN terminated (terminated) bearer. In addition, in MR-DC, the radio bearer in which PDCP is placed in the secondary node can be called an SN terminated (terminated) bearer. It should be noted that, in MR-DC, the radio bearer in which RLC bearer exists only in MCG can be called an MCG bearer (MCG bearer). In addition, in MR-DC, the radio bearer in which RLC bearer exists only in SCG can be called an SCG bearer (SCG bearer). In addition, in DC, the radio bearer in which RLC bearer exists in both MCG and SCG can be called a split bearer (split bearer).

[0101] When MR-DC is set for the terminal device, the bearer type of SRB1 and SRB2 established and / or set in the terminal device may be an MN terminated MCG bearer and / or an MN terminated split bearer. In addition, when MR-DC is set for the terminal device, the bearer type of SRB3 established and / or set in the terminal device may be an SN terminated SCG bearer. In addition, when MR-DC is set for the terminal device, the bearer type of DRB established and / or set in the terminal device may be any one of all bearer types.

[0102] For the RLC bearers established and / or configured in the cell group composed of E-UTRA, the RLC entity established and / or configured may be E-UTRA RLC. In addition, for the RLC bearers established and / or configured in the cell group composed of NR, the RLC entity established and / or configured may be NR RLC. In the case where EN-DC is set for the terminal device, the PDCP entity established and / or configured for the MN terminated MCG bearer may be either E-UTRA PDCP or NR PDCP. In addition, in the case where EN-DC is set for the terminal device, the PDCP established and / or configured for the radio bearers of other bearer types, namely, MN terminated split bearer, MN terminated SCG bearer, SN terminated MCG bearer, SN terminated split bearer and SN terminated SCG bearer may be NR PDCP. In addition, in the case where NGEN-DC or NE-DC or NR-DC is set for the terminal device, the PDCP entity established and / or configured for the radio bearers in all bearer types may be NR PDCP.

[0103] It should be noted that in NR, the DRB established and / or set in the terminal device can be associated with a PDU session. An SDAP entity can be established and / or set in the terminal device for a PDU session. The SDAP entity, PDCP entity, RLC entity and logical channel established and / or set in the terminal device can be established and / or set through RRC signaling received by the terminal device from the base station device.

[0104] It should be noted that regardless of whether MR-DC is set, the master node is eNB102, and the network configuration with EPC104 as the core network can also be called E-UTRA / EPC. In addition, the master node is eNB102, and the network configuration with 5GC110 as the core network can be called E-UTRA / 5GC. In addition, the network configuration with 5GC110 as the core network in gNB108, which is the master node, can be called NR or NR / 5GC. When MR-DC is not set, the above-mentioned master node may refer to a base station device that communicates with a terminal device.

[0105] Next, the switching in LTE and NR is explained. Switching may refer to the process of UE122 in RRC connected state changing the serving cell from the source SpCell to the target SpCell. Switching may be part of the mobility control performed by RRC. Switching may be performed when UE122 receives RRC signaling indicating switching from eNB102 and / or gNB108. The RRC signaling indicating switching may refer to a message related to RRC connection reconfiguration including parameters indicating switching (e.g., an information element named MobilityControlInfo or an information element named ReconfigurationWithSync). It should be noted that the above-mentioned information element named MobilityControlInfo may be renamed as mobility control setting information element, or mobility control setting, or mobility control information. It should be noted that the above-mentioned information element named ReconfigurationWithSync may be renamed as synchronization reconfiguration information element or synchronization reconfiguration. In addition, the RRC signaling indicating switching may refer to a message indicating movement to a cell of another RAT (e.g., MobilityFromEUTRammand or MobilityFromNRcommand). In addition, the handover may be renamed as reconfiguration with sync. The reconfiguration with sync may be triggered by RRC, or by DCI or MAC control elements. In addition, the conditions under which UE 122 can perform handover may include when AS security is activated, when SRB2 is established, and when part or all of at least one DRB is established. The above handover may be renamed as layer 3 handover, etc.

[0106] The flow of RRC signaling transmitted and received between the terminal device and the base station device is described. Figure 4 This is a diagram showing an example of the flow of procedures for various settings in RRC according to the present embodiment. Figure 4 This is an example of a process in which RRC signaling is sent from a base station device (eNB102 and / or gNB108) to a terminal device (UE122).

[0107] exist Figure 4 In step S400, the base station device generates an RRC message. The generation of the RRC message in the base station device may be performed in order for the base station device to transmit system information (SI: System Information) and paging messages. In addition, the generation of the RRC message in the base station device may be performed in order to send RRC signaling for the base station device to process a specific terminal device. The processing performed on a specific terminal device may include, for example, security-related settings, resetting of the RRC connection, switching to a different RAT, termination of the RRC connection, release of the RRC connection, and other processing. The resetting of the RRC connection may include, for example, control of the radio bearer (establishment, change, release, etc.), control of the cell group (establishment, addition, change, release, etc.), measurement settings, switching, security key update, and other processing. In addition, the generation of the RRC message in the base station device may also be performed in order to respond to the RRC signaling sent from the terminal device. The response to the RRC signaling sent from the terminal device may include, for example, a response to an RRC setup request, a response to an RRC reconnection request, a response to an RRC restart request, and the like. The RRC message includes information (parameters) used for various information notifications and settings. These parameters may be referred to as fields and / or information elements, and may be expressed using ASN.1 (Abstract Syntax Notation One).

[0108] exist Figure 4 Then, the base station device sends the generated RRC signaling to the terminal device (step S402). Then, the terminal device processes the received RRC signaling if it needs to perform settings or other processing (step S404). The terminal device that performs the processing can send RRC signaling for response to the base station device (not shown).

[0109] RRC signaling is not limited to the above examples and can also be used for other purposes.

[0110] It should be noted that in MR-DC, the RRC on the master node side can be used to transmit RRC signaling for SCG side settings (cell group settings, radio bearer settings, measurement settings, etc.) between the terminal device. For example, in EN-DC or NGEN-DC, the RRC signaling of E-UTRA sent and received between eNB102 and UE122 can include NR's RRC signaling in the form of a container. In addition, in NE-DC, the RRC signaling of NR sent and received between gNB108 and UE122 can include E-UTRA's RRC signaling in the form of a container. RRC signaling for SCG side settings can be sent and received between the master node and the slave node.

[0111] It should be noted that, not limited to the case of using MR-DC, the RRC signaling for E-UTRA sent from eNB102 to UE122 may also include RRC signaling for NR, and the RRC signaling for NR sent from gNB108 to UE122 may also include RRC signaling for E-UTRA.

[0112] An example of parameters included in a message related to re-setting of an RRC connection is described. Figure 7 It means in Figure 4 An example of an ASN.1 representation of fields and / or information elements related to cell group configuration included in a message related to reconfiguration of an RRC connection in NR. Figure 8 It means in Figure 4 An example of an ASN.1 representation of fields and / or information elements related to cell group configuration included in a message related to RRC connection reconfiguration in E-UTRA. Figure 7 , Figure 8In the example of ASN.1 in this embodiment, <omitted> and <omitted in part> indicate that other information is omitted and is not part of the ASN.1 expression. It should be noted that in places where there is no such record as <omitted> or <omitted in part>, the information element may be omitted. It should be noted that in this embodiment, the example of ASN.1 does not correctly follow the ASN.1 expression method. In this embodiment, the example of ASN.1 is an example of expressing the parameters of the RRC signaling of this embodiment, and other names and other expressions may also be used. In addition, in order to avoid complicating the description, the example of ASN.1 only represents an example of the main information closely related to this embodiment. It should be noted that sometimes all parameters expressed by ASN.1 are also referred to as information elements, without distinguishing between fields, information elements, etc. In addition, in this embodiment, the fields, information elements, etc. expressed by ASN.1 included in the RRC signaling may be renamed as information or parameters. It should be noted that the message related to the RRC connection reconfiguration may refer to the RRC connection reconfiguration message in NR or the RRC connection reconfiguration message in E-UTRA.

[0113] exist Figure 7In the information element named CellGroupConfig, the information element named CellGroupConfig may be an information element for setting, changing, releasing, etc. of the cell group of MCG or SCG in NR. The information element named CellGroupConfig may be renamed as cell group setting information element or cell group setting. The information element named SpCellConfig included in the information element named CellGroupConfig may be an information element for setting a special cell (SpCell). The information element named SpCellConfig may be renamed as SpCell setting information element or SpCell setting. The information element named SCellConfig included in the information element named CellGroupConfig may be an information element for setting a secondary cell (SCell). The information element named SCellConfig may be renamed as SCell setting information element or SCell setting. The information element named ReconfigurationWithSync included in the information element named SpCellConfig may be the above-mentioned synchronous reconfiguration information element or synchronous reconfiguration. The information element named ReconfigurationWithSync may include a new UE identifier named newUE-Identity. The information element named spCellConfigCommon included in the information element named ReconfigurationWithSync may be an information element indicating common settings set in SpCell. The information element named spCellConfigCommon may be renamed SpCell common settings. The information element named sCellConfigCommon included in the information element named SCellConfig may be an information element indicating common settings set in SCell. The information element named sCellConfigCommon may be renamed SCell common settings.

[0114] Fig. 9 Yes means Figure 7An example of an ASN.1 representation of an information element named ServingCellConfigCommon included in the SpCell setting or SCell setting, i.e., fields and / or information elements related to the common setting of the serving cell. The information element named DownlinkConfigCommon included in the information element named ServingCellConfigCommon may be an information element indicating the common setting set in the downlink. The information element named DownlinkConfigCommon may be renamed as downlink common setting. The information element named BWP-DownlinkCommon included in the information element named DownlinkConfigCommon may be an information element indicating the common setting set in the BWP of the downlink. The information element named BWP-DownlinkCommon may be renamed as downlink BWP common setting. The information element named PDCCH-ConfigCommon included in the information element named BWP-DownlinkCommon may be an information element indicating the common setting set in the PDCCH. The information element named PDCCH-ConfigCommon may be renamed as PDCCH common setting. The information element named PDCCH-ConfigCommon may include an information element named commonSearchSpaceList, an information element named searchSpaceSIB1, an information element named searchSpaceOtherSystemInformation and / or an information element named pagingSearchSpace. The information element named commonSearchSpaceList may be a list of common search spaces (Common Search Space: CSS). In addition, the information element named searchSpaceSIB1 may be information about a search space for receiving system information (SIB1). In addition, searchSpaceOtherSystemInformation may include information about a search space for receiving system information (after SIB2). In addition, the information element named pagingSearchSpace may be information about a search space for receiving a paging message.

[0115] The RRC reconfiguration procedure is described. The RRC reconfiguration procedure may refer to a procedure for reconfiguring parameters, information elements, etc. configured in the RRC. In addition, the purpose of the RRC reconfiguration procedure may be part or all of the following (A) to (F). (A) Modify the RRC connection (B) Implementing Synchronous Resetting (C) Setting, modifying and / or releasing measurements (D) Add, modify and / or release one or more SCells and cell groups (E) Add, modify and / or release the conditional handover (CHO) settings (F) Adding, modifying and / or releasing the setting of conditional PSCell change (CPC) or conditional PSCell addition (CPA)

[0116] The base station device (network: Network) can initiate the RRC reconfiguration process for the terminal device in the RRC_CONNECTED state. At this time, the base station device can apply part or all of the following (A) to (F) in the RRC reconfiguration process. It should be noted that "the base station device initiates the RRC reconfiguration process for the terminal device" can also be renamed as "the base station device sends a message related to the reconfiguration of the RRC connection to the terminal device". (A) Establishment of radio bearers other than SRB1 (B) Addition of SCG and one or more SCells (C) Synchronization reconfiguration included in the SCG cell group configuration (D) Synchronization reconfiguration included in the cell group configuration of MCG (E) Conditional Reconfiguration for Conditional PSCell Change (F) Conditional Reconfiguration for Conditional Switching or Conditional PSCell Addition

[0117] The synchronization re-setting accompanied by security key update included in the message related to the re-setting of the RRC connection may include part or all of the following (A) to (E) triggered by an explicit layer 2 indicator (L2 indicator). (A) Random access to PCell and / or PSCell (B) MAC reset (C) Security Updates (D) Re-establishment of RLC (E) Re-establishment of PDCP

[0118] The synchronous re-setting without security key update included in the message related to the re-setting of the RRC connection may include part or all of the following (A) to (D) triggered by an explicit layer 2 indicator (L2 indicator). (A) Random access to PCell and / or PSCell (B) MAC reset (C) Re-establishment of RLC (D) PDCP data recovery

[0119] It should be noted that the above-mentioned second layer indicator may include, for example, second layer signaling based on MAC, RLC, PDCP, etc.

[0120] When receiving a message related to the re-establishment of the RRC connection or when performing a conditional re-establishment (CHO, CPA, or CPC), the terminal device may perform part or all of the following (A) to (E). (Processing RRP) (A) If the message related to the re-establishment of the RRC connection is applied by conditional re-establishment when executing the cell selection within the running period of timer T311 started at the start of the RRC re-establishment procedure, all entries in the entry list described later are removed. (B) If the message related to the reconfiguration of the RRC connection includes the cell group setting of the MCG, the setting of the cell group received for the cell group setting of the MCG is implemented, and if the cell group setting includes the SpCell setting accompanied by the synchronization reconfiguration information element, the synchronization reconfiguration is implemented. (C) If the message related to the reconfiguration of the RRC connection includes the cell group setting of the SCG, the setting of the cell group for the SCG is implemented, and the synchronous reconfiguration is implemented when the cell group setting includes the SpCell setting accompanied by the synchronous reconfiguration information element. (D) If the message related to the reconfiguration of the RRC connection includes conditional reconfiguration, the conditional reconfiguration is implemented. (E) In order to send using the new configuration, the RRC reconfiguration complete message is submitted to the lower layer (PHY, MAC, etc.).

[0121] The terminal device may perform part or all of the following (A) to (E) in order to execute synchronization resetting. "Execute synchronization resetting" may be renamed as "implement synchronization resetting" or "trigger synchronization resetting". (Processing RWS) (A) If the timer T310 for the corresponding SpCell is running, stop it. (B) If the timer T312 for the corresponding SpCell is running, stop it. (C) Reset the MAC entity of the corresponding cell group. (D) The value of the new UE identifier (newUE-Identity) included in the synchronization reconfiguration information element is applied as the C-RNTI for the corresponding cell group. (E) Set the lower layer (PHY, etc.) according to the received SpCell common settings.

[0122] Next, conditional reconfiguration is described. Conditional reconfiguration may refer to conditional switching, conditional PSCell addition and / or conditional PSCell change. The network sets one or more conditional reconfiguration target candidate cells for the terminal device. The terminal device evaluates the state of the set candidate cells. The terminal device performs the evaluation and applies the conditional reconfiguration information element associated with the candidate cell that meets the execution condition. In addition, the terminal device may save a list of entries described later (VarConditionalReconfig) for conditional reconfiguration.

[0123] In response to receiving information related to conditional reconfiguration, the terminal device may erase the target candidate cell of the conditional reconfiguration when the information related to the conditional reconfiguration includes a deletion list (condReconfigToRemoveList) of entries. In addition, the terminal device may add or modify the target candidate cell of the conditional reconfiguration when the information related to the conditional reconfiguration includes an addition modification list (condReconfigToAddModList) of entries.

[0124] The action of erasing the conditionally reconfigured target candidate cell may refer to the case where the identifier of the entry (condReconfigId) included in the deletion list of the entry is included in the list of entries saved by the terminal device, and the terminal device erases the entry corresponding to the identifier of the entry from the list of entries saved by the terminal device. It should be noted that in the following description, the list of entries saved by the terminal device is also referred to as the entry list. That is, the "entry list" in the following description refers to the list of entries saved by the terminal device unless otherwise specified. In addition, the entry list may also be a variable named VarConditionalReconfig. In addition, the identifier of the entry is also referred to as the entry identifier.

[0125] The action of adding or modifying the conditionally reconfigured target candidate cell may refer to the terminal device performing the following processing (A) and / or (B) when each entry identifier included in the addition and modification list of entries exists in the entry of the entry list. (A) When an entry included in the additional modification list of an entry includes an execution condition (condExcutionCond), the execution condition of an entry of the entry list matching the entry identifier of the entry is replaced with the execution condition included in the additional modification list of the entry. (B) When an entry included in the additional modification list of an entry includes a conditional reconfiguration information element (condRRCReconfig), the conditional reconfiguration information element included in the additional modification list of the entry is replaced with the conditional reconfiguration information element of the entry list matching the entry identifier of the entry.

[0126] Furthermore, when an entry identifier included in the entry addition and modification list is not included in the entry list, the terminal device may add a new entry corresponding to the entry identifier not included in the entry list to the entry list.

[0127] It should be noted that the deletion list of entries may refer to a list related to the settings of one or more candidate SpCells to be deleted. The addition and modification list of entries may refer to a list related to the settings of one or more candidate SpCells added and modified for CHO, CPC and CPA. Each entry included in the addition and modification list of entries may include an entry identifier, and in addition, may also include an execution condition and / or a conditional re-setting information element. Each entry may be associated with one of the one or more candidate SpCells. The entry identifier refers to an identifier for identifying each entry of CHO, CPA and CPC. The entry list may include one or more entries. Each entry may include an entry identifier, one or more execution conditions and a conditional re-setting information element. In the case where the entry list saved by the terminal device does not include an entry, the terminal device may also save an empty list. The execution condition may refer to a condition that must be met in order to trigger the execution of the conditional re-setting. The conditional re-setting information element may refer to a message related to the re-setting of the RRC connection that is applied when the execution condition is met. The message related to the re-setting of the RRC connection may be a message for connecting to the candidate SpCell.

[0128] The terminal device may evaluate the execution condition of the item included in the item list stored in the terminal device. In the case where the item list stored in the terminal device is empty or the item list is not stored, the execution condition may not be evaluated.

[0129] Performing conditional reconfiguration may mean, when one or more execution conditions are met, applying the conditional reconfiguration information element included in the same entry as the one or more execution conditions to perform an RRC reconfiguration procedure based on the conditional reconfiguration information element.

[0130] When there are multiple candidate cells that satisfy the execution condition, the terminal device can select one cell from the multiple candidate cells that satisfy the execution condition and apply the conditional reconfiguration information element associated with the selected candidate cell.

[0131] When the upper layer (RRC, etc.) requests a reset of the MAC entity, the MAC entity of the terminal device may implement part or all of the following (A) to (O). The reset of the MAC entity may be renamed as a MAC reset. In addition, the processing of implementing part of the following (A) to (O) by the MAC entity of the terminal device may be renamed as a partial MAC reset, or may be renamed as a process of partially resetting the MAC entity. "Partially resetting the MAC entity" may be renamed as "instructing a partial reset of the MAC entity", etc. (Processing MR) (A) Initialize the parameter Bj set for each logical channel to 0. (B) If all timers are running, stop them. (C) Set the value of the New Data Indicator (NDI) of all uplink HARQ processes to 0. (D) If present, stop the ongoing random access procedure. (E) If present, explicitly signaled, 4-step and 2-step RA type contention-free Random Access (CFRA) resources are discarded. (F) Refresh the buffer of Msg3. (G) Refresh the MSGA buffer. (H) If present, cancel the triggered SR process. (I) If present, cancel the triggered BSR process. (J) If present, cancel the triggered PHR process. (K) If present, cancel the confirmation of the triggered configured uplink grant. (L) Flush the soft buffers of all downlink HARQ processes. (M) In each downlink HARQ process, the next received transmission for a certain transport block (TB) is considered to be the very first transmission. (N) If present, release the Temporary C-RNTI. (O) Reset all BFI_COUNTERs.

[0132] The operation of multiple transmit / receive points (multiple Transmit / Receive Point: multi-TRP, or also called mTRP) is described.

[0133] In mTRP operation, the serving cell may be able to schedule terminal devices from multiple TRPs (Transmit / Receive Points) to provide better coverage, reliability and / or data rate for PDSCH, PDCCH, PUSCH and PUCCH.

[0134] There may be two different operating modes for scheduling PDSCH transmissions of mTRPs. The two operating modes may be single-DCI and multi-DCI. Control of uplink and downlink operations for both modes may be performed in the PHY layer and MAC layer using settings set by the RRC layer. In single-DCI mode, terminal devices may be scheduled for both TRPs via the same DCI. In multi-DCI mode, terminal devices may be scheduled for each TRP via independent DCIs.

[0135] Each TRP in the mTRP may also be determined by TRP information. For example, the TRP information may be information for determining one TRP in one or more TRPs. For example, the TRP information may also be an index for determining a TRP. For example, a TRP may also be determined based on the TRP information. For example, the TRP information may also be information for determining one or more TRPs. The TRP information may also be used to select a TRP. The TRP information may also be a CORESET pool index. A CORESET pool index and a CORESET resource set identifier may be associated with a CORESET. The terminal device may also send a PUSCH in the corresponding TRP based on the CORESET resource set identifier. The TRP information may also be associated with an index of a CORESET resource pool. For example, a first CORESET pool index may be associated with a first TRP, and a second CORESET pool index may be associated with a second TRP. The TRP information may also be associated with a pool of TCI states (or a pool index of TCI states). For example, a first TCI state pool (or a pool index) may be associated with a first TRP, and a second TCI state pool (or a pool index) may be associated with a second TRP.

[0136] There may be two different operating modes for scheduling PDCCH transmissions of mTRPs. The two operating modes may be PDCCH repetition and PDCCH transmission based on a single frequency network (SFN). In the two-party mode, the terminal device may receive each of the PDCCH transmissions carrying the same DCI from each TRP. In the PDCCH repetition mode, the terminal device may receive two PDCCH transmissions carrying the same DCI from search spaces that have two corresponding links established with different CORESETs, respectively. In the SFN-based PDCCH transmission mode, the terminal device may receive two PDCCH transmissions carrying the same DCI from a single search space / CORESET using different TCI states.

[0137] In mTRP PUSCH repetition, the terminal device can perform PUSCH transmission of the same content in beam directions associated with different spatial relations corresponding to two TRPs, based on a single DCI or an indication of a configured uplink grant provided by RRC signaling.

[0138] In inter-cell mTRP operation, one or more TCI states in a multi-DCI PDSCH transmission can be associated with an SSB of a PCI different from the serving cell's physical cell identity (PCI). In addition, a maximum of one TCI state associated with a PCI different from the serving cell can be activated at one time.

[0139] Next, the centralized unit (CU) and the distributed unit (DU) are explained. The centralized unit may refer to the logical node of the RRC layer, SDAP layer, and PDCP layer of the hosting base station device. In addition, the distributed unit may refer to the logical node of the RLC layer, MAC layer, and PHY layer of the hosting base station device. The centralized unit may control the operation of one or more distributed units. In addition, one distributed unit may support one or more cells, and one cell may be supported by only one distributed unit. That is, one distributed unit can establish a correspondence through one or more cells.

[0140] Next, the first layer / second layer mobility (L1 / L2 mobility) in this embodiment is described. The first layer / second layer mobility may refer to a process (procedure) in which a base station device indicates a change of one or more service cells to a terminal device by enabling the terminal device to determine the target (change destination) of the service cell through the DCI or MAC control element of one or more cells of the service cell or ... In the first layer / second layer mobility, the base station device may also indicate the change of one or more service cells to the terminal device based on one or more measurement reports (measurement reports) received from the terminal device by enabling the terminal device to determine the DCI or MAC control element of the target one or more cells of the service cell. It should be noted that "first layer / second layer mobility" can be renamed as "first layer / second layer based inter-cell mobility (L1 / L2 based inter-cell mobility)", "first layer / second layer inter-cell mobility (L1 / L2 inter-cell mobility)", "first layer / second layer service cell change processing", "first layer / second layer service cell change" or "first layer / second layer switching", etc. "DCI of one or more cells that enables the terminal device to determine the target of the service cell" can be renamed as "DCI indicating the change of the service cell to one or more cells of the target", "DCI that changes one or more service cells of the terminal device", etc., and "MAC control elements of one or more cells that enable the terminal device to determine the target of the service cell" can be renamed as "MAC control elements that indicate the change of the service cell to one or more cells of the target", "MAC control elements that change one or more service cells of the terminal device", etc. In addition, DCI can be renamed as layer 1 signaling, etc., and MAC control elements can be renamed as layer 2 signaling, etc. The first layer can be a PHY layer, and the second layer can be one of a MAC layer, an RLC layer, a PDCP layer, and an SDAP layer. In addition, the above-mentioned measurement can be performed by the first layer and / or the third layer, i.e., the RRC layer.

[0141] In the first layer / second layer mobility, the candidate of one or more target cells of the service cell of the terminal device changed by the base station device may be referred to as a candidate cell (candidate cell), and may also be referred to as other names such as a candidate target cell (candidate target cell). In the first layer / second layer mobility, before the terminal device changes one or more service cells to one or more target cells, the base station device may set one or more candidate cells for the terminal device. In the first layer / second layer mobility, the candidate cell may be a SpCell or a SCell. In the first layer / second layer mobility, the group (a set of cells) consisting of the candidate of one or more target cells of the service cell of the terminal device changed by the base station device may be referred to as a candidate cell group (Candidate Cell Group: CCG), and may also be referred to as other names such as a candidate cell set (candidate cell set), a configured cell set (configured cell set), etc. In the first layer / second layer mobility, the CCG may be a group consisting of a part or all of the cells included in the MCG or SCG. In the first layer / second layer mobility, one or more CCGs may be set by a base station device for the terminal device before the terminal device changes one or more service cells to one or more target cells. In the first layer / second layer mobility, a candidate target may refer to the candidate cell mentioned above, or may refer to the CCG mentioned above. In addition or instead, in the first layer / second layer mobility, the candidate target may include both the candidate cell and the CCG mentioned above. In the first layer / second layer mobility, the target one or more cells may be one or more cells determined by enabling the terminal device to determine the DCI or MAC control element of the target one or more cells of the service cell from one or more candidate cells set for the terminal device and / or one or more CCGs set for the terminal device.

[0142] In the first layer / second layer mobility, the setting of information indicating one or more candidate cells and / or one or more CCGs provided by the base station device to the terminal device may be referred to as the first layer / second layer inter-cell mobility candidate target configuration (L1 / L2 inter-cell mobility candidate target configuration), and may also be referred to as other names such as candidate target configuration, candidate target setting, candidate cell setting, CCG setting, etc. In addition or instead of this, in the first layer / second layer mobility, the first layer / second layer inter-cell mobility candidate target configuration may refer to the setting of information indicating one or more candidate targets provided by the base station device to the terminal device. In the first layer / second layer mobility, the first layer / second layer inter-cell mobility candidate target configuration may include the setting of one or more candidate targets, and may also include the setting of measurements and / or wireless bearers applied to one or more candidate targets. In the first layer / second layer mobility, the base station device may prepare one or more candidate cells, and provide the first layer / second layer inter-cell mobility candidate target configuration including the setting of the candidate cells to the terminal device. At this time, the terminal device can start measuring and reporting the candidate cells to the base station device when receiving the first layer / second layer inter-cell mobility candidate target setting. In addition or instead, in the first layer / second layer mobility, the base station device can prepare one or more CCGs and provide the terminal device with the first layer / second layer inter-cell mobility candidate target setting including the setting of the CCG. At this time, the terminal device can start measuring and reporting each candidate cell of the CCG to the base station device when receiving the first layer / second layer inter-cell mobility candidate target setting. For example, in the first layer / second layer mobility, the base station device can notify the terminal device of information indicating which candidate cell or which CCG it is through the DCI that changes one or more service cells of the terminal device, thereby the terminal device changes one or more service cells. In addition, for example, in the first layer / second layer mobility, the base station device can notify the terminal device of information indicating which candidate cell or which CCG it is through the MAC control element that changes one or more service cells of the terminal device, thereby the terminal device changes one or more service cells.

[0143] In the first layer / second layer mobility, some or all of the following mobility scenarios (A) to (C) may be supported, and other mobility scenarios may also be supported. In addition, in a terminal device without CA, the following mobility scenario (A) may be a scenario of changing only the PCell, and in a terminal device with CA, the following mobility scenario (A) may be a scenario of changing the PCell and one or more SCells. (A) PCell Change (B) Intra-distributed unit (intra-DU) mobility and intra-CU-inter-DU mobility (C) Inter-cell beam management

[0144] In the layer 1 / layer 2 mobility, the following principles (A) and / or (B) may be applied. (A) The base station device prepares the first layer / second layer inter-cell mobility candidate target configuration so that dynamic switching can be performed without full configuration. (B) The user plane continues to communicate without resetting as much as possible to avoid additional delays for data loss and data recovery.

[0145] In the first layer / second layer mobility, the first layer / second layer inter-cell mobility candidate target setting can be pre-notified through the following (A) to (C) RRC signaling or other control information (RRC signaling, etc.), and the terminal device can save (store) the first layer / second layer inter-cell mobility candidate target setting until a DCI or MAC control element indicating the change of the serving cell to one or more target cells is received from the first layer or the second layer. In addition, in the intra-distributed unit mobility and the intra-distributed unit mobility of the centralized unit, the first layer / second layer inter-cell mobility candidate target setting can be common, and part of the first layer / second layer inter-cell mobility candidate target setting can also be different. It should be noted that the first layer / second layer inter-cell mobility candidate target setting can include part or all of the system information (searchSpaceSIB1, searchSpaceOtherSystemInformation, etc.), paging messages (pagingSearchSpace, etc.), and common search spaces (commonSearchSpaceList, etc.). In addition, in the first layer / second layer mobility, security key updates may not be performed. (A) Messages related to re-establishment of RRC connection for each candidate target (B) Cell group settings for each candidate target (C) SpCell setting or SCell setting for each candidate target

[0146] The handover interruption time (HO interruption time) for layer 1 / layer 2 mobility may refer to the time from when the terminal device receives the DCI or MAC control element indicating the change of the serving cell to one or more target cells from the first layer or the second layer to when the downlink / uplink transmission and reception is first performed in the beam of the one or more target cells. In addition, the handover interruption time for layer 1 / layer 2 mobility may include the time for processing part or all of the following (A) to (F). It should be noted that the "handover interruption time for layer 1 / layer 2 mobility" may be renamed as "delay for layer 1 / layer 2 mobility" or the like. (A) Reconfiguration of UE (B) Measurements in Layer 1 and / or RRC (C) Downlink synchronization (D) Uplink synchronization (E)TRS (Temporary RS) tracking (F) CSI-RS measurement

[0147] Based on the above description, various embodiments of the present invention are described. It should be noted that the processes omitted in the following description can be applied to the processes described above.

[0148] Figure 5 1 is a block diagram showing the configuration of the terminal device (UE122) according to the present embodiment. Figure 5 Only the main components closely related to this embodiment are shown.

[0149] Figure 5The UE 122 shown is composed of a receiving unit 500 that receives control information (DCI, RRC signaling, etc.) from a base station device, a processing unit 502 that performs processing according to parameters included in the received control information, and a sending unit 504 that sends control information (UCI, RRC signaling, etc.) to the base station device. The above-mentioned base station device may refer to eNB 102 or gNB 108. In addition, the processing unit 502 may include part or all of the functions of various layers (for example, physical layer, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, and NAS layer). That is, the processing unit 502 may include part or all of the physical layer processing unit, MAC layer processing unit, RLC layer processing unit, PDCP layer processing unit, SDAP processing unit, RRC layer processing unit, and NAS layer processing unit.

[0150] Figure 6 is a block diagram showing the configuration of a base station device according to this embodiment. Figure 6 Only the main components closely related to this embodiment are shown. The above-mentioned base station device can refer to eNB102 or gNB108.

[0151] Figure 6 The base station device shown is composed of a sending unit 600 that sends control information (DCI, RRC signaling, etc.) to UE122, a processing unit 602 that generates control information (including DCI, parameter RRC signaling, etc.) and sends it to UE122 so that the processing unit 502 of UE122 processes it, and a receiving unit 604 that receives control information (UCI, RRC signaling, etc.) from UE122. In addition, the processing unit 602 may include part or all of the functions of various layers (such as the physical layer, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, and NAS layer). That is, the processing unit 602 may include part or all of the physical layer processing unit, the MAC layer processing unit, the RLC layer processing unit, the PDCP layer processing unit, the SDAP processing unit, the RRC layer processing unit, and the NAS layer processing unit.

[0152] use Fig.10 An example of processing performed by the terminal device according to the present embodiment will be described.

[0153] Fig.10 This is a diagram showing an example of processing of a terminal device according to the present embodiment. RRC 308 of processing unit 502 of UE 122 that receives a MAC control element from transmission unit 600 of gNB 108 makes a condition judgment (step S1000), and takes action based on the judgment (step S1002).

[0154] The RRC 308 of the processing unit 502 of the UE 122 may determine in step S1000 whether any one or any combination of the following (a) to (e) is satisfied. (a) The MAC control element received from the transmitting unit 600 of gNB 108 is a MAC control element indicating a change of the serving cell to one or more target cells. (b) The MAC control element received from the transmitting unit 600 of gNB 108 includes information indicating that the MAC entity is reset when the serving cell changes. (c) The MAC control element received from the transmitting unit 600 of gNB 108 includes information for instructing a partial reset of the MAC entity when the serving cell changes. (d) The MAC control element received from the transmitting unit 600 of gNB 108 includes information indicating that the RLC entity is reestablished when the serving cell is changed. (e) The MAC control element received from the transmitting unit 600 of gNB 108 includes information indicating that the PDCP entity is reestablished when the serving cell is changed.

[0155] If RRC308 of the processing unit 502 of UE122 determines in step S1000 that the condition (a) is satisfied, the serving cell may be changed to one or more cells of the target in step S1002. If RRC308 of the processing unit 502 of UE122 determines in step S1000 that the condition (a) is satisfied, the serving cell may not be changed to one or more cells of the target in step S1002. In addition, if RRC308 of the processing unit 502 of UE122 determines in step S1000 that the condition (b) is satisfied, the MAC entity may be reset in step S1002 when the serving cell is changed. At this time, MAC302 of the processing unit 502 of UE122 may implement part or all of the processing shown in the above processing (MR) in step S1002 when the serving cell is changed. In addition, if RRC308 of the processing unit 502 of UE122 determines in step S1000 that the condition (b) is not satisfied, the MAC entity may not be reset in step S1002 when the serving cell is changed. At this time, MAC302 of the processing unit 502 of UE122 may not perform part or all of the processing as shown in the above processing (MR) when the serving cell is changed in step S1002. In addition, when RRC308 of the processing unit 502 of UE122 determines in step S1000 that the condition (c) is satisfied, it may instruct in step S1002 to partially reset the MAC entity when the serving cell is changed. At this time, MAC302 of the processing unit 502 of UE122 may perform part of the processing as shown in the above processing (MR) when the serving cell is changed in step S1002. In addition, when RRC308 of the processing unit 502 of UE122 determines in step S1000 that the condition (c) is not satisfied, it may not instruct in step S1002 to partially reset the MAC entity when the serving cell is changed. At this time, MAC302 of the processing unit 502 of UE122 may not perform part or all of the processing as shown in the above processing (MR) when the serving cell is changed in step S1002. In addition, if RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (d) is satisfied, in step S1002, the RLC entity may be re-established when the serving cell is changed; if it is determined that condition (d) is not satisfied, the RLC entity may not be re-established when the serving cell is changed in step S1002. In addition, if RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (e) is satisfied, in step S1002, the PDCP entity may be re-established when the serving cell is changed; if it is determined that condition (e) is not satisfied, the PDCP entity may not be re-established when the serving cell is changed in step S1002.The MAC control elements described in the conditions (a) to (e) may be shared among multiple conditions or may be independent of each other.

[0156] In addition, use Fig.10 Another example of the processing of the terminal device of the present embodiment is described. The RRC308 of the processing unit 502 of the UE122 that indicates the change of the serving cell to one or more target cells from the lower layer (first layer or second layer) of a cell group including at least one SpCell makes a conditional judgment (step S1000), and takes action based on the judgment (step S1002).

[0157] The RRC 308 of the processing unit 502 of the UE 122 determines in step S1000 whether the settings of the candidate targets are saved (stored). If it is determined that the settings of the candidate targets are saved, it can be determined whether one or both of the following (a) and (b) are satisfied. In addition, if the RRC 308 of the processing unit 502 of the UE 122 determines that the settings of the candidate targets are not saved, in step S1002, the serving cell may not be changed to one or more cells of the target. (A) The candidate target setting includes information #A. (b) The candidate target setting includes information #B.

[0158] The information #A may include any one or any combination of the following (a-1) to (a-4), and the information #A may also include other information. (a-1) indicates information about resetting the MAC entity when the serving cell changes. (a-2) Information indicating that a partial reset of the MAC entity is performed when the serving cell is changed (a-3) Information indicating that the RLC entity is reestablished when the serving cell is changed (a-4) Information indicating re-establishment of the PDCP entity when the serving cell changes

[0159] RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (a) is satisfied. When the information #A includes the above-mentioned information (a-1), in step S1002, RRC308 of processing unit 502 of UE122 may implement the following processing (a'-1). When the information #A does not include the above-mentioned information (a-1), in step S1002, RRC308 of processing unit 502 of UE122 may not implement the following processing (a'-1). In addition, when RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (a) is satisfied, and when the information #A includes the above-mentioned information (a-2), in step S1002, RRC308 of processing unit 502 of UE122 may implement the following processing (a'-2); when the information #A does not include the above-mentioned information (a-2), in step S1002, RRC308 of processing unit 502 of UE122 may not implement the following processing (a'-2). In addition, when RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (a) is satisfied, and when the information #A includes the above-mentioned information (a-3), in step S1002, RRC308 of processing unit 502 of UE122 may implement the following processing (a'-3); when the information #A does not include the above-mentioned information (a-3), in step S1002, RRC308 of processing unit 502 of UE122 may not implement the following processing (a'-3). In addition, if RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (a) is satisfied, and if the information #A includes the above-mentioned information (a-4), in step S1002, RRC308 of processing unit 502 of UE122 may implement the following processing (a'-4), and if the information #A does not include the above-mentioned information (a-4), in step S1002, RRC308 of processing unit 502 of UE122 may not implement the following processing (a'-4). In addition, if RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (a) is satisfied, and if the information #A includes other information, in step S1002, RRC308 of processing unit 502 of UE122 may implement the following processing other than (a'-1) to (a'-4). The following processes (a'-1) to (a'-4) can be combined with each other. In addition, the following process (a'-1) can be, for example, part or all of the process shown in the above process (MR), and the following process (a'-2) can be, for example, part of the process shown in the above process (MR). (a'-1) When the serving cell changes, the MAC entity of the cell group is reset. (a'-2) indicates that when the serving cell changes, a partial reset is performed on the MAC entity of the cell group. (a'-3) Re-establish the RLC entity when the serving cell changes. (a'-4) Re-establish the PDCP entity when the serving cell changes.

[0160] The information #B may include any one or any combination of the following (b-1) to (b-2), and the information #B may also include other information. (b-1) Information indicating the group to which each candidate target belongs (b-2) List information of candidate targets

[0161] RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (b) is satisfied. When information #B includes the information (b-1), it can determine whether to implement part or all of the processing of (a'-1) to (a'-4) based on the information (b-1). For example, when one or more target cells indicated from the lower layer belong to the same group as part or all of the cells before the service cell change, RRC308 of processing unit 502 of UE122 can determine in step S1000 not to implement part or all of the processing of (a'-1) to (a'-4), and not implement part or all of the processing of (a'-1) to (a'-4) based on the determination in step S1002. In addition, when one or more cells of the target indicated from the lower layer belong to a different group from some or all of the cells before the serving cell change, RRC308 of the processing unit 502 of UE122 can judge in step S1000 to implement some or all of the above-mentioned processing (a'-1) to (a'-4), and implement some or all of the above-mentioned processing (a'-1) to (a'-4) based on the judgment in step S1002. It should be noted that the above-mentioned information (b-1), for example, can be an identifier indicating the group to which each candidate target belongs. Alternatively, the above-mentioned information (b-1) can also be a list information of candidate targets belonging to each group. For example, the identifier for identifying each candidate cell is included in the list information corresponding to each group, and the terminal device can judge that the candidate cells of the identifier included in the list information of the same group belong to the same group. In addition, the group recorded in the above-mentioned information (b-1) can be set by gNB108 based on any one of the following (b-1-1) to (b-1-6) or any combination. (b-1-1) Distributed units supporting each candidate target within the same centralized unit (b-1-2) Whether it is necessary to reset the MAC entity of the cell group when the serving cell changes (b-1-3) Whether it is necessary to indicate that a partial reset of the MAC entity of the cell group is performed when the serving cell changes (b-1-4) Is it necessary to re-establish the RLC entity when the serving cell changes? (b-1-5) Is it necessary to re-establish the PDCP entity when the serving cell changes? (b-1-6) Other conditions

[0162] RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (b) is satisfied. When the information #B includes the information (b-2), RRC308 may determine whether to implement part or all of the processing of (a'-1) to (a'-4) based on the information (b-2). For example, when the settings corresponding to one or more target cells indicated from the lower layer are included in the information (b-2), RRC308 of processing unit 502 of UE122 may determine in step S1000 not to implement part or all of the processing of (a'-1) to (a'-4), and not implement part or all of the processing of (a'-1) to (a'-4) based on the determination in step S1002. In addition, when the settings corresponding to one or more target cells indicated from the lower layer are not included in the information (b-2), the RRC308 of the processing unit 502 of the UE122 may determine in step S1000 to implement part or all of the above-mentioned processing (a'-1) to (a'-4), and implement part or all of the above-mentioned processing (a'-1) to (a'-4) based on the judgment in step S1002. It should be noted that the candidate target corresponding to the settings included in the information (b-2) can be determined by the gNB108, for example, based on whether the candidate target supports mobility within the distributed unit. In addition to or instead of this, the candidate target corresponding to the settings included in the information (b-2) can be determined by the gNB108, for example, based on whether the PCI of the candidate target is consistent with a PCI different from the serving cell.

[0163] If RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (a) is not satisfied, in step S1002, it may determine whether to implement part or all of the above-mentioned processing (a'-1) to (a'-4) based on information other than information #A. In addition, if RRC308 of processing unit 502 of UE122 determines in step S1000 that condition (b) is not satisfied, in step S1002, it may determine whether to implement part or all of the above-mentioned processing (a'-1) to (a'-4) based on information other than information #B.

[0164] The embodiments may also be combined with each other. In each embodiment, when determining whether information #A is included in the setting of a candidate target, if the setting of the candidate target includes information indicating that the processing corresponding to information #A is not implemented or information indicating that the processing corresponding to information #A is not implemented, RRC 308 of processing unit 502 of UE 122 may determine that information #A is not included in the setting of the candidate target.

[0165] In each embodiment, information #A and information #B may include the following (A) to (D) RRC signaling or other control information (RRC signaling, etc.) in the setting of the candidate target. It should be noted that in each embodiment, the list information may be information representing a list of settings or parameters including one or more of the following (A) to (D), and the list may be, for example, a list of items. In addition, in each embodiment, information #A and information #B may be shared in the setting of the candidate target, or may be represented independently. (A) Messages related to re-establishment of RRC connection for each candidate target (B) Cell group settings for each candidate target (C) SpCell setting or SCell setting for each candidate target (D) Conditional resetting for each candidate target

[0166] In each embodiment, the setting of candidate targets saved by the terminal device may be one or more. In addition or instead, the one or more cells of the target indicated from the lower layer in the serving cell change may be one or more candidate cells and / or one or more CCGs. In addition or instead, the setting of candidate targets may include the setting of one or more candidate cells and / or the setting of one or more CCGs. In addition, the cell group setting recorded in (B) above may include SpCell setting and / or SCell setting, and the setting of CCG indicated from the lower layer in the serving cell change may also be applied to the cell group of the lower layer.

[0167] According to non-patent document 7, in the existing handover, that is, the third layer handover, the UE triggers a synchronous reconfiguration. In addition, in the first layer / second layer mobility, regardless of whether the synchronous reconfiguration is triggered by RRC or by DCI or MAC control elements, the MAC entity is reset based on non-patent document 8. At this time, a part of the settings of the candidate target is erased, and in the first layer / second layer mobility, the UE sometimes needs to obtain a part of the settings of the candidate target again. According to the above embodiments, in the first layer / second layer mobility, the UE can save and use a part of the settings of the candidate target as it is, without erasing a part of the settings of the candidate target through synchronous reconfiguration.

[0168] Unless otherwise specified, the wireless bearer in the above description may be a DRB, an SRB, or a DRB and an SRB.

[0169] In addition, in the above description, expressions such as "user plane", "user plane protocol", and "user plane interface" can be replaced with each other.

[0170] In addition, in the above description, "receiving a DCI or MAC control element indicating a change of a serving cell to one or more target cells" may be renamed as "being indicated a change of a serving cell to one or more target cells".

[0171] In addition, in the above description, expressions such as "candidate target", "candidate cell", "CCG" and the like can be interchangeably used.

[0172] In addition, unless otherwise stated, the service cell change in the above description may be a first layer / second layer service cell change.

[0173] Furthermore, in the above description, expressions such as "notify", "accept the blame", etc. can be used interchangeably.

[0174] Furthermore, in the above description, expressions such as “associated with”, “establishing correspondence”, and “establishing association” can be interchangeable.

[0175] Furthermore, in the above description, expressions such as “include”, “contain”, “including”, etc. can be replaced with each other.

[0176] Furthermore, in the above description, "the" may be replaced by "the above-mentioned".

[0177] Furthermore, in the above description, expressions such as "determined to be ...", "set to be ...", and "including ..." can be replaced with each other.

[0178] In addition, in the examples of each processing or the examples of the processes of each processing in the above description, some or all of the steps may not be executed. In addition, in the examples of each processing or the examples of the processes of each processing in the above description, the order of the steps may be different. In addition, in the examples of each processing or the examples of the processes of each processing in the above description, some or all of the processing in each step may not be executed. In addition, in the examples of each processing or the examples of the processes of each processing in the above description, the order of the processing in each step may be different. In addition, in the above description, "based on A, perform B" may also be renamed as "perform B". That is, "perform B" may also be performed independently of "is A".

[0179] It should be noted that in the above description, "A may be renamed as B" includes not only the meaning of renaming A as B, but also the meaning of renaming B as A. In addition, in the above description, when "C may be D" and "C may be E" are recorded, the case of "D may be E" may be included. In addition, in the above description, when "F may be G" and "G may be H" are recorded, the case of "F may be H" may be included.

[0180] Furthermore, in the above description, when the condition “A” and the condition “B” are opposite conditions, the condition “B” can be expressed as an “other” condition of the condition “A”.

[0181] The program operated by the device of this embodiment can be a program that controls the central processing unit (CPU) and the like to make the computer function to realize the functions of this embodiment. The program or the information processed by the program is temporarily read into a volatile memory such as a random access memory (RAM) or stored in a non-volatile memory such as a flash memory or a hard disk drive (HDD) during processing, and is read, modified, or written by the CPU as needed.

[0182] It should be noted that a part of the device in the above-mentioned embodiment can be implemented by a computer. In this case, the program for implementing the control function can be recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. The "computer system" mentioned here refers to a computer system built into the device, and includes a computer system of hardware such as an operating system and peripherals. In addition, the "computer-readable recording medium" can be any one of a semiconductor recording medium, an optical recording medium, a magnetic recording medium, etc.

[0183] Furthermore, "computer-readable recording medium" may also include: a recording medium that stores a program dynamically for a short period of time, such as a communication line when the program is transmitted via a network such as the Internet or a communication line such as a telephone line; and a recording medium that stores a program for a fixed period of time, such as a volatile memory inside a computer system that serves as a server or client in this case. In addition, the above program may be a program for realizing a part of the above functions, or a program that can realize the above functions by combining with a program already recorded in a computer system.

[0184] In addition, each functional block or each feature of the device used in the above-mentioned embodiments can be implemented or executed by a circuit, that is, typically by an integrated circuit or multiple integrated circuits. Circuits designed in a manner to perform the functions described in this specification may include: a general-purpose processor, a digital signal processor (DSP), an integrated circuit for a specific purpose (ASIC), a field programmable gate array (FPGA) or other programmable logic elements, discrete gates or transistor logic, discrete hardware parts, or a combination thereof. The general-purpose processor may be a microprocessor, and the processor may also be replaced by an existing processor, controller, microcontroller or state machine. The general-purpose processor or the above-mentioned circuits may be composed of digital circuits or analog circuits. In addition, in the case of an integrated circuit technology that replaces the existing integrated circuits as semiconductor technology advances, integrated circuits based on this technology may also be used.

[0185] It should be noted that the present embodiment is not limited to the above-mentioned embodiment. In the embodiment, an example of a device is described, but the present embodiment is not limited thereto and can be applied to fixed or non-movable electronic devices set up indoors and outdoors, such as AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other terminal devices or communication devices such as other living equipment.

[0186] The present embodiment has been described in detail with reference to the accompanying drawings, but the specific configuration is not limited to the present embodiment, and also includes design changes within the scope of the gist of the present embodiment. In addition, the present embodiment can be modified in various ways within the scope indicated by the claims, and the embodiment obtained by appropriately combining the technical solutions disclosed in different embodiments is also included in the technical scope of the present embodiment. In addition, it also includes a configuration obtained by replacing elements that have the same effect as the elements described in the above embodiments with each other. Industrial Applicability

[0187] One aspect of the present invention can be used for example in a communication system, a communication device (such as a mobile phone device, a base station device, a wireless LAN device, or a sensor device), an integrated circuit (such as a communication chip), a program, or the like. Description of Reference Numerals 100: E-UTRA 102: eNB 104: EPC 106: NR 108: gNB 110:5GC 112, 114, 116, 118, 120, 124: Interface 122:UE 200, 300: PHY 202, 302: MAC 204, 304: RLC 206, 306: PDCP 208, 308: RRC 310: SDAP 210, 312: NAS 500, 604: Receiving department 502, 602: Processing Department 504, 600: Sending department

Claims

1. A terminal device, the terminal device communicating with a base station device, wherein: The terminal device includes an RRC processing unit, In the case where a serving cell change to a candidate cell is indicated from a lower layer of a certain cell group, the RRC processing unit determines whether to re-establish an RLC entity when the serving cell is changed based on the setting of the candidate cell stored in the RRC processing unit, In the case where it is determined that the RLC entity is to be re-established when the serving cell is changed, the RRC processing unit re-establishes the RLC entity, When it is determined that the RLC entity is not to be re-established when the serving cell is changed, the RRC processing unit does not re-establish the RLC entity.

2. A method, the method being a method of a terminal device communicating with a base station device, wherein: The following steps are involved: In the case where a serving cell change to a candidate cell is indicated from a lower layer of a certain cell group, the RRC entity of the terminal device determines whether to re-establish an RLC entity when the serving cell is changed based on the setting of the candidate cell stored by the RRC entity; In a case where it is determined that the RLC entity is to be re-established when the serving cell is changed, the RRC entity re-establishes the RLC entity; and When it is determined that the RLC entity is not to be re-established when the serving cell is changed, the RRC entity does not re-establish the RLC entity.

3. An integrated circuit installed in a terminal device communicating with a base station device, wherein: The integrated circuit performs the following functions: In the case where a serving cell change to a candidate cell is indicated from a lower layer of a certain cell group, the RRC entity of the terminal device determines whether to re-establish an RLC entity when the serving cell is changed based on the setting of the candidate cell stored by the RRC entity; In a case where it is determined that the RLC entity is to be re-established when the serving cell is changed, the RRC entity re-establishes the RLC entity; and When it is determined that the RLC entity is not to be re-established when the serving cell is changed, the RRC entity does not re-establish the RLC entity.

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