Terminal device, base station device, and method

Abstract

Provided is a terminal device that communicates with a base station device and comprises a reception unit and a processing unit. The reception unit receives a MAC CE that includes one Random Access Resource that is associated with one candidate cell from the base station device, and the processing unit uses the Random Access Resource to perform Random Access with respect to the candidate cell on the basis of cell selection being triggered and it being determined that the cell selected by the cell selection is the candidate cell.

Description

Terminal device, base station device, and method

[0001] The present invention relates to a terminal device, a base station device, and a method. This application claims priority from Japanese Patent Application No. 2025-013842 filed in Japan on January 30, 2025, the content of which is incorporated herein by reference.

[0002] In the 3rd Generation Partnership Project (3GPP (registered trademark)), which is a standardization project for cellular mobile communication systems, technical studies and standard setting for cellular mobile communication systems, including radio access, core network, services, etc., are being carried out.

[0003] For example, in 3GPP, E-UTRA (Evolved Universal Terrestrial Radio Access) was started for technical study and standard setting as a radio access technology (RAT) for cellular mobile communication systems for the 3.9th generation and 4th generation. Even now, in 3GPP, technical study and standard setting for extended technologies of E-UTRA are being carried out. Note that E-UTRA is also referred to as Long Term Evolution (LTE (registered trademark)), and extended technologies may be referred to as LTE-Advanced (LTE-A) and LTE-Advanced Pro (LTE-A Pro).

[0004] Also, in 3GPP, NR (New Radio, or NR Radio access) was started for technical study and standard setting as a radio access technology (RAT) for cellular mobile communication systems for the 5th generation (5G). Even now, in 3GPP, technical study and standard setting for extended technologies of NR are being carried out.

[0005] 3GPP TS 38.300 v18.2.0,"NR;NR and NG-RAN Overall description; Stage 2" pp103-1053GPP TS 38.214 v18.3.0," NR;Physical layer measurements " pp9-103GPP TS 38.215 v18.3.0,"NR;NR and NG-RAN Overall description; Stage 2"pp98-1013GPP TS 38.331 v18.2.0,"NR;Radio Resource Control (RRC);Protocol specifications" pp43-458

[0006] In the current LTM (Landing Time Module), cell switching is triggered by receiving a CSC (Cell Switch Command) from the base station equipment. However, consideration has begun to support conditional LTM, which triggers cell switching by determining whether the terminal equipment has met certain conditions.

[0007] One aspect of the present invention has been made in view of the above circumstances, and one of its objectives is to provide a terminal device, a base station device, a communication method, and an integrated circuit that can efficiently perform communication control.

[0008] To achieve the above objective, one aspect of the present invention employs the following means. That is, one aspect of the present invention is a terminal device that communicates with a base station device, comprising a receiving unit and a processing unit, wherein the receiving unit receives a MAC CE from the base station device that includes one Random Access Resource associated with one candidate cell, and the processing unit performs Random Access on the candidate cell using the Random Access Resource based on the fact that cell selection has been triggered and the cell selected in the cell selection is determined to be the candidate cell.

[0009] Another aspect of the present invention is a base station device that communicates with a terminal device, comprising a transmitting unit that transmits a MAC CE to the terminal device, and a processing unit, wherein the processing unit includes a Random Access Resource associated with one candidate cell in the MAC CE, and transmits the MAC CE to the terminal device, thereby causing the terminal device to perform Random Access on the candidate cell using the Random Access Resource, based on the determination that cell selection has been triggered and that the cell selected in the cell selection is the candidate cell.

[0010] Another aspect of the present invention is a method implemented in a terminal device that communicates with a base station device, the method being implemented in a terminal device that communicates with a base station device, the method being to receive a MAC CE from the base station device that includes one Random Access Resource associated with one candidate cell, triggering cell selection, and, based on the determination that the cell selected in the cell selection is the candidate cell, to perform Random Access on the candidate cell using the Random Access Resource.

[0011] These comprehensive or specific embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or recording media, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media.

[0012] According to one aspect of the present invention, terminal devices, methods, and integrated circuits can achieve efficient communication control processing.

[0013] A schematic diagram of the communication system according to this embodiment. A diagram of an example of the E-UTRA protocol configuration according to this embodiment. A diagram of an example of the NR protocol configuration according to this embodiment. A diagram showing an example of the procedure flow for various settings in RRC according to this embodiment. A block diagram showing the configuration of the terminal device in this embodiment. A block diagram showing the configuration of the base station device in this embodiment. An example of the ASN.1 description included in the message regarding the reconfiguration of the RRC connection in NR in this embodiment. An example of the ASN.1 description representing the fields and / or information elements related to the ServingCellConfigCommon information element in this embodiment. An example of the processing of the terminal device in this embodiment.

[0014] This embodiment will now be described in detail with reference to the drawings.

[0015] LTE (and LTE-A, LTE-A Pro) and NR may be defined as different Radio Access Technologies (RATs). NR may also be defined as a technology included in LTE. Furthermore, LTE that can connect with NR via Multi-Radio Dual Connectivity (MR-DC) may be distinguished from conventional LTE. Also, LTE using 5GC in the Core Network (CN) may be distinguished from conventional LTE using EPC in the Core Network. Conventional LTE may refer to LTE that does not implement technologies standardized in 3GPP Release 15 or later. This embodiment may be applied to NR, LTE, and other RATs. The following description uses terms related to LTE and NR, but this embodiment may be applied to other technologies using other terms. Also, the term E-UTRA in this embodiment may be replaced with the term LTE, and the term LTE may be replaced with the term E-UTRA.

[0016] In this embodiment, the names of each node and entity, and the processing at each node and entity, will be described when the wireless access technology is E-UTRA or NR. However, this embodiment may be used with other wireless access technologies. The names of each node and entity in this embodiment may be different.

[0017] Figure 1 is a schematic diagram of the communication system according to this embodiment. The functions of each node, wireless access technology, core network, interface, etc., described using Figure 1 are only some of the functions closely related to this embodiment, and other functions may also be present.

[0018] E-UTRA100 may be a wireless access technology. E-UTRA100 may also be an air interface between UE122 and eNB102. The air interface between UE122 and eNB102 may be called the Uu interface. eNB (E-UTRAN Node B)102 may be a base station device. eNB102 may have the E-UTRA protocol described below. The E-UTRA protocol may consist of the E-UTRA User Plane (UP) protocol and the E-UTRA Control Plane (CP) protocol described below. eNB102 may terminate the E-UTRA User Plane (UP) protocol and the E-UTRA Control Plane (CP) protocol to UE122. The wireless access network composed of eNB may be called E-UTRAN.

[0019] The EPC (Evolved Packet Core) 104 may be a core network. Interface 112 is an interface between eNB 102 and EPC 104 and may be called the S1 interface. Interface 112 may have a control plane interface through which control signals pass, and / or a user plane interface through which user data passes. The control plane interface of interface 112 may terminate at a Mobility Management Entity (MME: not shown) in EPC 104. The user plane interface of interface 112 may terminate at a Serving Gateway (S-GW: not shown) in EPC 104. The control plane interface of interface 112 may be called the S1-MME interface. The user plane interface of interface 112 may be called the S1-U interface.

[0020] One or more eNB102s may be connected to the EPC104 via interface 112. Interfaces may exist between multiple eNB102s connected to the EPC104 (not shown). Interfaces between multiple eNB102s connected to the EPC104 may be called X2 interfaces.

[0021] NR106 may be a wireless access technology. NR106 may also be an air interface between UE122 and gNB108. The air interface between UE122 and gNB108 may be called a Uu interface. gNB108 may be a base station device. gNB108 may have the NR protocol described below. The NR protocol may consist of the NR User Plane (UP) protocol and the NR Control Plane (CP) protocol described below. gNB108 may terminate the NR User Plane (UP) protocol and the NR Control Plane (CP) protocol to UE122.

[0022] 5GC110 may be the core network. Interface 116 is the interface between gNB108 and 5GC110 and may be called the NG interface. Interface 116 may have a control plane interface through which control signals pass, and / or a user plane interface through which user data passes. The control plane interface of interface 116 may be terminated by the Access and Mobility Management Function (AMF: not shown) in 5GC110. The user plane interface of interface 116 may be terminated by the User Plane Function (UPF: not shown) in 5GC110. The control plane interface of interface 116 may be called the NG-C interface. The user plane interface of interface 116 may be called the NG-U interface.

[0023] One or more gNB108s may be connected to the 5GC110 via interface 116. Interfaces may exist between multiple gNB108s connected to the 5GC110 (not shown). The interfaces between multiple gNB108s connected to the 5GC110 may be called Xn interfaces.

[0024] eNB102 may have the function of connecting to 5GC110. eNB102 having the function of connecting to 5GC110 may be called ng-eNB. Interface 114 is the interface between eNB102 and 5GC110 and may be called NG interface. Interface 114 may have a control plane interface through which control signals pass, and / or a user plane interface through which user data passes. The control plane interface of interface 114 may be terminated at the AMF in 5GC110. The user plane interface of interface 114 may be terminated at the UPF in 5GC110. The control plane interface of interface 114 may be called NG-C interface. The user plane interface of interface 114 may be called NG-U interface. A radio access network consisting of ng-eNB or gNB may be called NG-RAN. NG-RAN, E-UTRAN, etc. may simply be called a network. Also, the network may include eNB, ng-eNB, and gNB, etc.

[0025] One or more eNB102s may be connected to the 5GC110 via interface 114. Interfaces may exist between multiple eNB102s connected to the 5GC110 (not shown). Interfaces between multiple eNB102s connected to the 5GC110 may be called Xn interfaces. Furthermore, an eNB102 connected to the 5GC110 and a gNB108 connected to the 5GC110 may be connected via interface 120. Interface 120 between an eNB102 connected to the 5GC110 and a gNB108 connected to the 5GC110 may be called Xn interfaces.

[0026] gNB108 may have the function of connecting to EPC104. gNB108 with the function of connecting to EPC104 may be called en-gNB. Interface 118 is the interface between gNB108 and EPC104 and may be called the S1 interface. Interface 118 may have a user plane interface through which user data passes. The user plane interface of interface 118 may be terminated at the S-GW (not shown) in EPC104. The user plane interface of interface 118 may be called the S1-U interface. Also, eNB102 connected to EPC104 and gNB108 connected to EPC104 may be connected by interface 120. Interface 120 between eNB102 connected to EPC104 and gNB108 connected to EPC104 may be called the X2 interface.

[0027] Interface 124 is the interface between EPC104 and 5GC110, and may be an interface that passes only CP, only UP, or both CP and UP. In addition, some or all of interfaces such as Interface 114, Interface 116, Interface 118, Interface 120, and Interface 124 may not exist depending on the communication system provided by the telecommunications carrier.

[0028] UE122 may be a terminal device capable of receiving system information and paging messages transmitted from eNB102 and / or gNB108. UE122 may also be a terminal device capable of wireless connection with eNB102 and / or gNB108. Furthermore, UE122 may be a terminal device capable of simultaneously establishing wireless connections with eNB102 and gNB108. UE122 may have the E-UTRA protocol and / or the NR protocol. Note that the wireless connection may be a Radio Resource Control (RRC) connection.

[0029] Furthermore, UE122 may be a terminal device capable of connecting to EPC104 and / or 5GC110 via eNB102 and / or gNB108. If the core network to which eNB102 and / or gNB108, with which UE122 communicates, is connected is EPC104, then each Data Radio Bearer (DRB) established between UE122 and eNB102 and / or gNB108, as described below, may be uniquely associated with each EPS (Evolved Packet System) bearer passing through EPC104. Each EPS bearer may be identified by an EPS bearer identifier (Identity, or ID). Furthermore, the same QoS may be guaranteed for data such as IP packets and Ethernet® frames passing through the same EPS bearer.

[0030] Furthermore, if the core network to which UE122 communicates with eNB102 and / or gNB108 is connected is 5GC110, then each DRB established between UE122 and eNB102 and / or gNB108 may be further associated with one of the PDU (Packet Data Unit) sessions established within 5GC110. Each PDU session may have one or more QoS flows. 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). Each QoS flow may also be identified by a QoS flow identifier (Identity, or ID). Furthermore, the same QoS may be guaranteed for data such as IP packets and Ethernet frames passing through the same QoS flow.

[0031] EPC104 does not need to have PDU sessions and / or QoS flows. Similarly, 5GC110 does not need to have an EPS bearer. When UE122 is connected to EPC104, UE122 will have EPS bearer information, but not information within PDU sessions and / or QoS flows. Similarly, when UE122 is connected to 5GC110, UE122 will have information within PDU sessions and / or QoS flows, but not information within EPS bearers.

[0032] In the following description, eNB102 and / or gNB108 will also be simply referred to as base station equipment, and UE122 will also be simply referred to as terminal equipment or UE.

[0033] Figure 2 is a diagram of an example of the E-UTRA protocol architecture according to this embodiment. Figure 3 is a diagram of an example of the NR protocol architecture according to this embodiment. Note that the functions of each protocol described using Figure 2 and / or Figure 3 are some of the functions closely related to this embodiment, and other functions may be present. In this embodiment, the uplink (UL) may be a link from a terminal device to a base station device. Also in this embodiment, the downlink (DL) may be a link from a base station device to a terminal device.

[0034] Figure 2(A) is a diagram of the E-UTRA user plane (UP) protocol stack. As shown in Figure 2(A), the E-UTRA UP protocol may be a protocol between UE122 and eNB102. That is, the E-UTRA UP protocol may be a protocol that terminates at eNB102 on the network side. As shown in Figure 2(A), the E-UTRA user plane protocol stack may consist of a radio physical layer (PHY) 200, a medium access control layer (MAC) 202, a radio link control layer (RLC) 204, and a packet data convergence protocol layer (PDCP) 206.

[0035] Figure 3(A) is a diagram of the NR User Plane (UP) protocol stack. As shown in Figure 3(A), the NRUP protocol may be a protocol between UE122 and gNB108. That is, the NR UP protocol may be a protocol that terminates at gNB108 on the network side. As shown in Figure 3(A), the NR User Plane protocol stack may consist of the wireless physical layer PHY300, the media access control layer MAC302, the wireless link control layer RLC304, the packet data convergence protocol layer PDCP306, and the service data adaptation protocol layer (service data adaptation protocol layer) SDAP (Service Data Adaptation Protocol)310.

[0036] Figure 2(B) shows the configuration of the E-UTRA control plane (CP) protocol. As shown in Figure 2(B), in the E-UTRA CP protocol, the Radio Resource Control (RRC) 208, which is the radio resource control layer, may be a protocol between the UE122 and the eNB102. That is, the RRC 208 may be a protocol that terminates at the eNB102 on the network side. Also, in the E-UTRA CP protocol, the Non Access Stratum (NAS) 210, which is the non-Access Stratum (AS) layer, may be a protocol between the UE122 and the MME. That is, the NAS 210 may be a protocol that terminates at the MME on the network side.

[0037] Figure 3(B) is a diagram of the NR control plane (CP) protocol configuration. As shown in Figure 3(B), in the NR CP protocol, the RRC308, which is the radio resource control layer, may be a protocol between the UE122 and the gNB108. That is, the RRC308 may be a protocol that terminates at the gNB108 on the network side. Also, in the NR CP protocol, the NAS312, which is a non-AS layer, may be a protocol between the UE122 and the AMF. That is, the NAS312 may be a protocol that terminates at the AMF on the network side.

[0038] The AS (Access Stratum) layer may be a layer that terminates between UE122 and eNB102 and / or gNB108. That is, the AS layer may be a layer containing some or all of PHY200, MAC202, RLC204, PDCP206, and RRC208, and / or a layer containing some or all of PHY300, MAC302, RLC304, PDCP306, SDAP310, and RRC308.

[0039] In this embodiment, the following terms may be used without distinguishing between the E-UTRA protocol and the NR protocol, and may include PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), RRC (RRC layer), and NAS (NAS layer). In this case, PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), RRC (RRC layer), and NAS (NAS layer) may 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, or they may be the PHY (PHY layer), MAC (MAC layer), RLC (RLC layer), PDCP (PDCP layer), RRC (RRC layer), and NAS (NAS layer) of the NR protocol. Also, SDAP (SDAP layer) may be the SDAP (SDAP layer) of the NR protocol.

[0040] Furthermore, in this embodiment, when distinguishing between the E-UTRA protocol and the NR protocol, PHY200, MAC202, RLC204, PDCP206, and RRC208 may also be referred to as E-UTRA PHY 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. Additionally, PHY200, MAC202, RLC204, PDCP206, and RRC208 may also be described as E-UTRA PHY 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. Furthermore, 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 PDCP, and NR RRC, respectively. Alternatively, PHY300, MAC302, RLC304, PDCP306, and RRC308 may be written as NR PHY, NR MAC, NR RLC, NR PDCP, and NR RRC, respectively.

[0041] This section describes entities in the AS layer of E-UTRA and / or NR. Entities that possess some or all of the functions of the MAC layer may be called MAC entities. Entities that possess some or all of the functions of the RLC layer may be called RLC entities. Entities that possess some or all of the functions of the PDCP layer may be called PDCP entities. Entities that possess some or all of the functions of the SDAP layer may be called SDAP entities. Entities that possess some or all of the functions of the RRC layer may be called RRC entities. MAC entities, RLC entities, PDCP entities, SDAP entities, and RRC entities may be replaced with MAC, RLC, PDCP, SDAP, and RRC, respectively.

[0042] Furthermore, the data provided from MAC, RLC, PDCP, and SDAP to lower layers, and / or the data provided from lower layers to MAC, RLC, PDCP, and SDAP, may be referred to as MAC PDU (Protocol Data Unit), RLC PDU, PDCP PDU, and SDAP PDU, respectively. Also, the data provided from higher layers to MAC, RLC, PDCP, and SDAP, and / or the data provided from MAC, RLC, PDCP, and SDAP to higher layers, may be referred to as MAC SDU (Service Data Unit), RLC SDU, PDCP SDU, and SDAP SDU, respectively. In addition, a segmented RLC SDU may be referred to as an RLC SDU segment.

[0043] Here, the base station equipment and the terminal equipment exchange (send and receive) signals in the higher layer. For example, the base station equipment and the terminal equipment may send and receive RRC messages (also called RRC message, RRC information, or RRC signalling) in the Radio Resource Control (RRC) layer. The base station equipment and the terminal equipment may also send and receive MAC control elements in the MAC (Medium Access Control) layer. Furthermore, the RRC layer of the terminal equipment acquires system information broadcast from the base station equipment. Here, RRC messages, system information, and / or MAC control elements are also referred to as higher layer signals (higher layer signaling) or higher layer parameters (higher layer parameters). Each parameter included in the higher layer signal received by the terminal equipment may also be referred to as a higher layer parameter. In the processing of the PHY layer, the higher layer refers to the layer above the PHY layer, and may refer to one or more of the MAC layer, RRC layer, RLC layer, PDCP layer, NAS (Non Access Stratum) layer, etc. For example, in MAC layer processing, the upper layer may refer to one or more layers such as the RRC layer, RLC layer, PDCP layer, and NAS layer. Hereinafter, the meaning of "A is given (provided) in the upper layer" or "A is given (provided) by the upper layer" may mean that the upper layer of the terminal device (mainly the RRC layer or MAC layer, etc.) receives A from the base station device, and that received A is provided (provided) from the upper layer of the terminal device to the physical layer of the terminal device. For example, "being provided with upper layer parameters" in a terminal device may mean that it receives an upper layer signal from the base station device, and the upper layer parameters contained 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 in a terminal device may mean that the upper layer parameters are given (provided) to the terminal device.For example, the setting of upper layer parameters in 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. However, the setting of upper layer parameters in the terminal device may also include the setting of default parameters pre - given to the upper layer of the terminal device. When explaining the transmission of an RRC message from the terminal device to the base station device, the expression of submitting a message from the RRC entity of the terminal device to the lower layer (lower layer: lower layer) may be used. In the terminal device, "submitting a message to the lower layer" from the RRC entity may mean submitting the message to the PDCP layer. In the terminal device, "submitting (submit) a message to the lower layer" from the RRC layer may mean that since the RRC message is transmitted using SRBs (such as SRB0, SRB1, SRB2, SRB3), it means submitting it 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 mean one or more of the PHY layer, MAC layer, RLC layer, PDCP layer, etc.

[0044] An example of the functions of the PHY will be described. The PHY of the terminal device may have the function of receiving data transmitted from the PHY of the base station device via the downlink (Downlink: DL) physical channel. The PHY of the terminal device may have the function of transmitting data to the PHY of the base station device via the uplink (Uplink: UL) physical channel. The PHY may be connected to the upper - layer MAC via the transport channel. The PHY may pass data to the MAC via the transport channel. Also, the PHY may be provided with data from the MAC via the transport channel. In the PHY, an RNTI (Radio Network Temporary Identifier) may be used to identify various control information.

[0045] Here, the physical channel will be described. The physical channels used for wireless communication between the terminal device and the base station device may include the following physical channels.

[0046] 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)

[0047] PBCH may be used to notify the system information required by the terminal device.

[0048] Also, in NR, PBCH may be used to notify the time index (SSB-Index) within the period of the Synchronization Signal Block (SSB).

[0049] PDCCH may be used in downlink wireless communication (wireless communication from base station equipment to terminal equipment) to transmit (or carry) Downlink Control Information (DCI). Here, one or more DCIs (which may also be called DCI formats) may be defined for the transmission of downlink control information. That is, fields for downlink control information may be defined as DCIs and mapped to information bits. PDCCH may be transmitted in PDCCH candidates. Terminal equipment may monitor a set of PDCCH candidates in a serving cell. Monitoring a set of PDCCH candidates may mean attempting to decode a PDCCH according to a certain DCI format. Terminal equipment may also use a CORESET (Control Resource Set) to monitor a set of PDCCH candidates. The DCI format may be used for scheduling PUSCHs in a serving cell. PUSCHs may be used for transmitting user data or RRC messages, as described later.

[0050] PUCCH may be used to transmit Uplink Control Information (UCI) in uplink wireless communication (wireless communication from terminal equipment to base station equipment). Here, Uplink Control Information may include Channel State Information (CSI), which is used to indicate the state of the downlink channel. Furthermore, Uplink Control Information may include Scheduling Requests (SR), which are used to request UL-SCH (Uplink Shared Channel) resources. Furthermore, Uplink Control Information may include HARQ-ACK (Hybrid Automatic Repeat reQuest ACKnowledgement).

[0051] PDSCH may be used to transmit downlink data (DL-SCH: Downlink Shared Channel) from the MAC layer. In the case of downlinks, PDSCH may also be used to transmit system information (SI) and random access responses (RAR).

[0052] PUSCH may be used to transmit uplink data from the MAC layer (UL-SCH: Uplink Shared Channel) or HARQ-ACK and / or CSI along with uplink data. Alternatively, PUSCH may be used to transmit CSI only, or HARQ-ACK and CSI only. In other words, PUSCH may be used to transmit UCI only. Furthermore, PDSCH or PUSCH may be used to transmit RRC signaling (also called RRC message) and MAC CE. Here, in PDSCH, the RRC signaling transmitted from the base station equipment may be a common signaling for multiple terminal devices within a cell. Also, the RRC signaling transmitted from the base station equipment may be dedicated signaling for a particular terminal device (also called dedicated signaling). In other words, terminal device-specific information may be transmitted using dedicated signaling for a particular terminal device. Furthermore, PUSCH may be used to transmit UE Capability on the uplink.

[0053] PRACH may be used to send a random access preamble. PRACH may also be used to indicate the initial connection establishment procedure, handover procedure, connection re-establishment procedure, synchronization (timing adjustment) for uplink transmissions, and requests for UL-SCH resources.

[0054] An example of MAC functionality is described below. MAC may be called a MAC sublayer. MAC may have the function of mapping various logical channels to corresponding transport channels. Logical channels may be identified by a Logical Channel Identity (Logical Channel ID). MAC may be connected to the higher-level RLC via logical channels. Logical channels may be divided into control channels that transmit control information and traffic channels that transmit user information, depending on the type of information being transmitted. Logical channels may also be divided into uplink logical channels and downlink logical channels. MAC may have the function of multiplexing MAC SDUs belonging to one or more different logical channels and providing them to the PHY. MAC may also have the function of demultiplexing MAC PDUs provided from the PHY and providing them to the higher layer via the logical channel to which each MAC SDU belongs. MAC may also have the function of performing error correction through HARQ (Hybrid Automatic Repeat reQuest). The MAC may also have a function to report scheduling information. The MAC may have a function to prioritize between terminal devices using dynamic scheduling. The MAC may also have a function to prioritize between logical channels within a single terminal device. The MAC may also have a function to prioritize overlapping resources within a single terminal device. The E-UTRA MAC may have a function to identify Multimedia Broadcast Multicast Services (MBMS). The NR MAC may also have a function to identify Multicast Broadcast Service (MBS). The MAC may have a function to select the transport format.A MAC may have functions for discontinuous reception (DRX) and / or discontinuous transmission (DTX), random access (RA) procedures, a power headroom report (PHR) function to notify information on available power, and a buffer status report (BSR) function to notify information on the amount of data in the transmit buffer. An NR MAC may have a bandwidth adaptation (BA) function. The MAC PDU format used in E-UTRA MACs and the MAC PDU format used in NR MACs may be different. A MAC PDU may also include MAC control elements (MAC CEs), which are elements for controlling the MAC.

[0055] This section describes the logical channels used for uplink (UL) and / or downlink (DL) in E-UTRA and / or NR.

[0056] BCCH (Broadcast Control Channel) may be a downlink logical channel for broadcasting control information, such as system information (SI).

[0057] A PCCH (Paging Control Channel) may be a downlink logical channel for carrying paging messages.

[0058] A Common Control Channel (CCCH) may be a logical channel for transmitting control information between a terminal device and a base station device. A CCCH may be used when a terminal device does not have an RRC connection. A CCCH may also be used between a base station device and multiple terminal devices.

[0059] A DCCH (Dedicated Control Channel) may be a logical channel for transmitting dedicated control information in a point-to-point, bidirectional manner between a terminal device and a base station device. Dedicated control information may be control information specific to each terminal device. A DCCH may be used when the terminal device has an RRC connection.

[0060] A Dedicated Traffic Channel (DTCH) may be a logical channel for transmitting user data point-to-point between a terminal device and a base station device. A DTCH may be a logical channel for transmitting dedicated user data. Dedicated user data may be user data specific to each terminal device. A DTCH may exist on both the uplink and downlink.

[0061] This section describes the mapping between logical channels and transport channels for uplinks in E-UTRA and / or NR.

[0062] CCCH may be mapped to UL-SCH (Uplink Shared Channel), which is an uplink transport channel.

[0063] DCCH may be mapped to UL-SCH (Uplink Shared Channel), which is an uplink transport channel.

[0064] DTCH may be mapped to UL-SCH (Uplink Shared Channel), which is an uplink transport channel.

[0065] This section describes the mapping between logical channels and transport channels in downlinks in E-UTRA and / or NR.

[0066] BCCH may be mapped to a downlink transport channel, which is a BCH (Broadcast Channel) and / or DL-SCH (Downlink Shared Channel).

[0067] The PCCH may be mapped to the PCH (Paging Channel), which is a downlink transport channel.

[0068] CCCH may be mapped to DL-SCH (Downlink Shared Channel), which is a downlink transport channel.

[0069] DCCH may be mapped to DL-SCH (Downlink Shared Channel), which is a downlink transport channel.

[0070] DTCH may be mapped to DL-SCH (Downlink Shared Channel), which is a downlink transport channel.

[0071] An example of RLC functionality is described below. RLC may be called an RLC sublayer. E-UTRA RLC may have the function of segmenting and / or concatenating data provided from the upper layer PDCP and providing it to the lower layer. E-UTRA RLC may have the function of reassembling and reordering data provided from the lower layer and providing it to the upper layer. NR RLC may have the function of adding a sequence number to data provided from the upper layer PDCP that is independent of the sequence number added by the PDCP. NR RLC may also have the function of segmenting data provided from the PDCP and providing it to the lower layer. NR RLC may also have the function of reassembling data provided from the lower layer and providing it to the upper layer. RLC may also have a data retransmission function and / or an automatic repeat request (ARQ) function. RLC may also have a function to perform error correction using ARQ. The control information sent from the receiver to the transmitter of RLC to perform ARQ, indicating data that needs to be retransmitted, may be called a status report. The instruction to send a status report sent from the transmitter to the receiver of RLC may be called a poll. RLC may also have a function to detect data duplication. RLC may also have a data discard function. RLC may have three modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). In TM, data received from the upper layer is not split, and an RLC header does not need to be added. The TM RLC entity is a unidirectional entity, and the terminal device may set the TM RLC entity as a transmitting TM RLC entity or a receiving TM RLC entity.UM performs data splitting and / or merging, adds an RLC header, etc., received from higher layers, but does not need to control data retransmission. UM RLC entities may be unidirectional or bidirectional. If a UM RLC entity is unidirectional, the terminal device may configure it as a transmitting UM RLC entity or a receiving UM RLC entity. If a UM RLC entity is bidirectional, the terminal device may configure it as a UM RLC entity consisting of a transmitting side and a receiving side. AM performs data splitting and / or merging, adds an RLC header, and controls data retransmission, etc., received from higher layers. AM RLC entities are bidirectional, and the terminal device may configure them as AM RLC entities consisting of a transmitting side and a receiving side. Data provided to lower layers by TM, and / or data provided from lower layers, may be called TMD PDUs. Furthermore, data provided to lower layers by UM, and / or data provided by lower layers, may be called UMDPDU. Similarly, data provided to lower layers by AM, or data provided by lower layers, may be called AMD PDU. The RLC PDU format used in E-UTRA RLC and the RLC PDU format used in NR RLC may be different. Additionally, there may be data RLC PDUs and control RLC PDUs. Data RLC PDUs may be called RLC DATA PDUs (RLC Data PDUs). Control RLC PDUs may be called RLC CONTROL PDUs (RLC Control PDUs).

[0072] This section describes some examples of PDCP functionality. PDCP may be referred to as the PDCP sublayer. PDCP may have a function for maintaining sequence numbers. PDCP may also have a header compression / decompression function for efficiently transmitting user data such as IP packets and Ethernet frames over the wireless section. The protocol used for compressing and decompressing IP packet headers may be called the ROHC (Robust Header Compression) protocol. The protocol used for compressing and decompressing Ethernet frame headers may be called the EHC (Ethernet® Header Compression) protocol. PDCP may also have data encryption / decryption functions. PDCP may also have data integrity protection and integrity verification functions. PDCP may also have a re-ordering function. PDCP may also have a PDCP SDU retransmission function. PDCP may also have a data discard function using a discard timer. PDCP may also have a duplication function. PDCP may also have a function to discard duplicate received data. A PDCP entity is a bidirectional entity and may consist of a transmitting PDCP entity and a receiving PDCP entity. The PDCP PDU format used in E-UTRA PDCP and the PDCP PDU format used in NR PDCP may be different. Furthermore, there may be data PDCP PDUs and control PDCP PDUs. The data PDCP PDU may be called a PDCP DATA PDU (PDCP Data PDU). The control PDCP PDU may be called a PDCP CONTROL PDU (PDCP Control PDU).

[0073] This section describes an example of SDAP functionality. SDAP is a Service Data Adaptive Protocol Layer (SPD). SDAP may have the function of mapping downlink QoS flows sent from the 5GC110 to the terminal device via the base station equipment to the Data Radio Bearer (DRB), and / or mapping uplink QoS flows sent from the terminal device to the 5GC110 via the base station equipment to the DRB. SDAP may also have the function of storing mapping rule information. SDAP may also have the function of marking QoS flow identifiers (QoS Flow ID: QFI). Note that there may be data SDAP PDUs and control SDAP PDUs. Data SDAP PDUs may be called SDAP DATA PDUs (SDAP Data PDUs). Control SDAP PDUs may be called SDAP CONTROL PDUs (SDAP Control PDUs). Note that there may be one SDAP entity for each PDU session in the terminal device.

[0074] An example of RRC functionality is described below. RRC may have broadcast functionality. RRC may have paging functionality from EPC104 and / or 5GC110. RRC may have paging functionality from eNB102 connected to gNB108 or 5GC110. RRC may also have RRC connection management functionality. RRC may also have wireless bearer control functionality. RRC may also have cell group control functionality. RRC may also have mobility control functionality. RRC may also have terminal device measurement reporting and terminal device measurement reporting control functionality. RRC may also have QoS management functionality. RRC may also have wireless link failure detection and recovery functionality. The RRC may use RRC messages to perform functions such as broadcasting, paging, RRC connection management, wireless bearer control, cell group control, mobility control, terminal device measurement reporting and terminal device measurement reporting control, QoS management, and wireless link failure detection and recovery. Note that the RRC messages and parameters used in E-UTRA RRC may differ from those used in NR RRC.

[0075] RRC messages may be sent using the logical channels BCCH, PCCH, CCCH, or DCCH. RRC messages sent using DCCH may also be referred to as dedicated RRC signaling or simply RRC signaling.

[0076] RRC messages sent using BCCH may include, for example, a Master Information Block (MIB), a System Information Block (SIB) of each type, or other RRC messages. RRC messages sent using PCCH may include, for example, a paging message or other RRC messages.

[0077] RRC messages sent in the uplink (UL) direction using CCCH may include, for example, RRC Setup Request, RRC Resume Request, RRC Reestablishment Request, and RRC System Info Request. They may also include, for example, RRC Connection Request, RRC Connection Resume Request, and RRC Connection Reestablishment Request. Other RRC messages may also be included.

[0078] RRC messages sent in the downlink (DL) direction using CCCH may include, for example, RRC Connection Reject messages, RRC Connection Setup messages, RRC Connection Reestablishment messages, and RRC Connection Reestablishment Reject messages. They may also include, for example, RRC Reject messages and RRC Setup messages. Other RRC messages may also be included.

[0079] RRC signaling sent in the uplink (UL) direction using DCCH may include, for example, a Measurement Report message, an RRC Connection Reconfiguration Complete message, an RRC Connection Setup Complete message, an RRC Connection Reestablishment Complete message, a Security Mode Complete message, and an UE Capability Information message. It may also include, for example, a Measurement Report message, an RRC Reconfiguration Complete message, an RRC Setup Complete message, an RRC Reestablishment Complete message, an RRC Resume Complete message, a Security Mode Complete message, and an UE Capability Information message. Other RRC signaling may also be included.

[0080] RRC signaling sent in the downlink (DL) direction using DCCH may include, for example, RRC Connection Reconfiguration messages, RRC Connection Release messages, Security Mode Command messages, and UE Capability Enquiry messages. It may also include, for example, RRC Reconfiguration messages, RRC Resume messages, RRC Release messages, RRC Reestablishment messages, Security Mode Command messages, and UE Capability Enquiry messages. Other RRC signaling may also be included.

[0081] This section describes some examples of NAS functionality. A NAS may have authentication capabilities. It may also have mobility management capabilities. Furthermore, a NAS may have security control capabilities.

[0082] The aforementioned PHY, MAC, RLC, PDCP, SDAP, RRC, and NAS functions are merely examples, and some or all of each function may not be implemented. Furthermore, some or all of the functions of each layer may be included in other layers.

[0083] Next, we will explain the state transitions of UE122 in LTE and NR. When a UE122 connected to an EPC or 5GC has an RRC connection, it may be in the RRC_CONNECTED state. The state of having an RRC connection may include the state in which the UE122 holds some or all of the UE context described below. The state of having an RRC connection may also include the state in which the UE122 can send and / or receive unicast data. When the RRC connection is suspended, the UE122 may be in the RRC_INACTIVE state. The UE122 may be in the RRC_INACTIVE state when it is connected to a 5GC and the RRC connection is suspended. When the UE122 is neither in the RRC_CONNECTED state nor the RRC_INACTIVE state, it may be in the RRC_IDLE state.

[0084] Note that if UE122 is connected to EPC, it does not have the RRC_INACTIVE state, but E-UTRAN may initiate the suspension of the RRC connection. When UE122 is connected to EPC and the RRC connection is suspended, UE122 may transition to the RRC_IDLE state, retaining the UE's AS context and the identifier (resumeIdentity) used for resuming. The upper layer of the UE122's RRC layer (e.g., the NAS layer) may initiate the resumption of the suspended RRC connection if UE122 retains the UE's AS context, E-UTRAN has permitted the resumption of the RRC connection, and UE122 needs to transition from the RRC_IDLE state to the RRC_CONNECTED state.

[0085] The definition of hibernation may differ between UE122 connected to EPC104 and UE122 connected to 5GC110. Furthermore, all or part of the procedure for UE122 to resume from hibernation may differ depending on whether UE122 is connected to EPC (when UE122 is hibernating in the RRC_IDLE state) or UE122 is connected to 5GC (when UE122 is hibernating in the RRC_INACTIVE state).

[0086] The RRC_CONNECTED state, RRC_INACTIVE state, and RRC_IDLE state may be referred to as connected mode, inactive mode, and idle mode, respectively, or as RRC connected mode, RRC inactive mode, and RRC idle mode.

[0087] The UE context held by UE122 may include all or part of the following: PDU session context, security key, UE radio capability information, and UE security capability information. The UE context held by either or all of eNB102 and gNB108 may contain the same information as the UE context held by UE122, or it may contain different information than that contained in the UE context held by UE122. Furthermore, the UE context may include all or part of the UE's AS context as described below.

[0088] The AS context of the UE held by UE122 may include all or part of the following information: the current RRC settings, the current security context, the PDCP status including the ROHC (RObust Header Compression) status, the C-RNTI (Cell Radio Network Temporary Identifier) ​​used by the source PCell, the cell identifier, and the physical cell identifier of the source PCell. The AS context of the UE held by any or all of eNB102 and gNB108 may include the same information as the AS context of the UE held by UE122, or it may include information different from the information included in the AS context of the UE held by UE122.

[0089] The security context may include all or part of the following at the AS level: the encryption key, the NH (Next Hop parameter), the NCC (Next Hop Chaining Counter parameter) used to derive the next hop access key, the identifier of the selected AS-level encryption algorithm, and the counter used for replay protection.

[0090] Next, we will explain the Serving Cell. In terminal devices in an RRC connection state where the CA and / or DC described later are not configured, the Serving Cell may consist of one Primary Cell (PCell). In terminal devices in an RRC connection state where the CA and / or DC described later are configured, multiple Serving Cells may mean a set of multiple cells consisting of one or more Special Cells (SpCells) and one or more all Secondary Cells (SCells). SpCells may support PUCCH transmission and contention-based Random Access (CBRA), and SpCells may always be activated. A PCell may be a cell used in the RRC connection establishment procedure when a terminal device in an RRC idle state transitions to an RRC connection state. A PCell may also be a cell used in the RRC connection re-establishment procedure when a terminal device re-establishes the RRC connection. A PCell may also be a cell used in the random access procedure during handover. PSCell may be a cell used in the random access procedure when adding a secondary node, as described later. SpCell may be a cell used for purposes other than those mentioned above.

[0091] If a group of serving cells configured by a terminal device consists of a SpCell and one or more SCells, it may be considered that the terminal device is configuring carrier aggregation (CA). Furthermore, for a terminal device configuring CA, a cell providing additional radio resources to a SpCell may be considered an SCell.

[0092] A group of serving cells configured by a terminal device in RRC, where the serving cells that use the same timing reference cell and the same timing advance value for the cell on which the terminal device sets the uplink, may be called a Timing Advance Group (TAG). A TAG containing a MAC entity SpCell may represent a Primary Timing Advance Group (PTAG). A TAG other than a PTAG may represent a Secondary Timing Advance Group (STAG). One or more of the aforementioned TAGs may be configured for each cell group, as described later.

[0093] This section describes cell groups, which are configured in the upper layer (RRC, etc.) of terminal devices. A cell group may consist of one SpCell. Alternatively, a cell group may consist of one SpCell and one or more SCells. In other words, a cell group may consist of one SpCell and, optionally, one or more SCells. A cell group may also be described as a set of cell(s).

[0094] Dual Connectivity (DC) is a technology that enables data communication using the radio resources of cell groups configured by a first base station device (first node) and a second base station device (second node). When DC or MR-DC (described later) is performed, cell groups may be added to terminal devices from the base station device. To perform DC, the first base station device may add a second base station device. The first base station device may be called the Master Node (MN). The cell group configured by the Master Node may be called the Master Cell Group (MCG). The second base station device may be called the Secondary Node (SN). The cell group configured by the Secondary Node may be called the Secondary Cell Group (SCG). The Master Node and Secondary Node may be configured within the same base station device.

[0095] Furthermore, when a terminal device does not configure a DC, the cell group configured by the terminal device may be called an MCG. Also, when a terminal device does not configure a DC, the SpCell configured by the terminal device may be a PCell. Furthermore, an NR in which the terminal device does not configure a DC may be called an NR standalone.

[0096] Furthermore, Multi-Radio Dual Connectivity (MR-DC) may be a technology that performs DC using E-UTRA for MCG and NR for SCG. Also, MR-DC may be a technology that performs DC using NR for MCG and E-UTRA for SCG. Also, MR-DC may be a technology that performs DC using NR for both MCG and SCG. MR-DC may be a technology included in DC. Examples of MR-DC using E-UTRA for MCG and NR for SCG include EN-DC (E-UTRA-NR Dual Connectivity) using EPC for the core network, and NGEN-DC (NG-RAN E-UTRA-NR Dual Connectivity) using 5GC for the core network. Also, an example of MR-DC using NR for MCG and E-UTRA for SCG is NE-DC (NR-E-UTRA Dual Connectivity) using 5GC for the core network. Also, an example of MR-DC using NR for both MCG and SCG is NR-DC (NR-NR Dual Connectivity) using 5GC for the core network.

[0097] In a terminal device, there may be one MAC entity for each cell group. For example, when a terminal device sets up a DC or MR-DC, there may be one MAC entity for the MCG and one MAC entity for the SCG. The MAC entity for the MCG in a terminal device may always be established in all states of the terminal device (RRC idle state, RRC connected state, and RRC inactive state, etc.). The MAC entity for the SCG in a terminal device may be created by the terminal device when it sets up the SCG. The MAC entities for each cell group in a terminal device may be set when the terminal device receives RRC signaling from the base station device. When a MAC entity is associated with an MCG, SpCell may mean PCell. When a MAC entity is associated with an SCG, SpCell may mean Primary SCG Cell (PSCell). When a MAC entity is not associated with a 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. Similarly, 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. Furthermore, in NR-DC, both the MAC entities for MCG and SCG may be NR MAC entities. Note that the statement that there is one MAC entity for each cell group can be rephrased as "there is one MAC entity for each SpCell." Similarly, the statement that there is one MAC entity for each cell group can be rephrased as "there is one MAC entity for each SpCell."

[0098] This section describes radio bearers. When a terminal device communicates with a base station device, a radio connection may be established between the terminal device and the base station device by establishing a radio bearer (RB). A radio bearer used in CP may be called a signaling radio bearer (SRB). A radio bearer used in UP may be called a data radio bearer (DRB). Each radio bearer may be assigned a radio bearer identifier (Identity: ID). The radio bearer identifier for SRBs may be called an SRB identifier (SRB Identity, or SRB ID). The radio bearer identifier for DRBs may be called a DRB identifier (DRB Identity, or DRB ID). For E-UTRA, SRB0 to SRB2 may be defined, and other SRBs may also be defined. For NR, SRB0 to SRB3 may be defined, and other SRBs may also be defined. SRB0 may be an SRB for RRC messages, transmitted and / or received using the logical channel CCCH. SRB1 may be an SRB for RRC signaling and for NAS signaling before SRB2 is established. RRC signaling transmitted and / or received using SRB1 may include piggybacked NAS signaling. All RRC and NAS signaling transmitted and / or received using SRB1 may use the logical channel DCCH. SRB2 may be an SRB for NAS signaling and for RRC signaling including logged measurement information. All RRC and NAS signaling transmitted and / or received using SRB2 may use the logical channel DCCH. SRB2 may also have a lower priority than SRB1. SRB3 may be an SRB for transmitting and / or receiving specific RRC signaling when a terminal device sets EN-DC, NGEN-DC, NR-DC, etc.All RRC signaling and NAS signaling transmitted and / or received using SRB3 may use the logical channel DCCH. Other SRBs may be provided for other purposes. The DRB may be a wireless bearer for user data. RRC signaling transmitted and / or received using the DRB may use the logical channel DTCH.

[0099] This section describes the wireless bearer in the terminal device. The wireless bearer may include an RLC bearer. An RLC bearer may consist of one or two RLC entities and a logical channel. If there are two RLC entities in the RLC bearer, the RLC entities may be a TM RLC entity and / or a transmit RLC entity and a receive RLC entity in unidirectional UM mode. SRB0 may consist of one RLC bearer. The RLC bearer of SRB0 may consist of a TM RLC entity and a logical channel. SRB0 may always be established in the terminal device in all states (RRC idle state, RRC connected state, and RRC inactive state, etc.). SRB1 may be established and / or configured by the terminal device in RRC when the terminal device transitions from the RRC idle state to the RRC connected state, based on RRC signaling received from the base station device. SRB1 may consist of one PDCP entity and one or more RLC bearers. The RLC bearer of SRB1 may consist of an AM RLC entity and a logical channel. SRB2 may be established and / or configured on a terminal device by RRC signaling received from the base station device by a terminal device in an RRC connection state with AS security activated. SRB2 may consist of one PDCP entity and one or more RLC bearers. The RLC bearer of SRB2 may consist of an AM RLC entity and a logical channel. Note that the PDCP on the base station side of SRB1 and SRB2 may be located on the master node. SRB3 may be established and / or configured on a terminal device by RRC signaling received from the base station device by a terminal device in an RRC connection state with AS security activated when a secondary node is added or when a secondary node is changed in EN-DC, NGEN-DC, or NR-DC. SRB3 may be a direct SRB between the terminal device and the secondary node. SRB3 may consist of one PDCP entity and one or more RLC bearers. The RLC bearers of SRB3 may consist of AM's RLC entities and logical channels.The PDCP on the base station side of SRB3 may be located on a secondary node. The DRB may be established and / or configured by the terminal device via RRC signaling received from the base station device by a terminal device in an RRC connection state with AS security activated. The DRB may consist of one PDCP entity and one or more RLC bearers. The RLC bearers of the DRB may consist of an AM or UM RLC entity and a logical channel.

[0100] In MR-DC, a wireless bearer with a PDCP on the master node may be called an MN-terminated bearer. Similarly, a wireless bearer with a PDCP on the secondary node may be called an SN-terminated bearer. Furthermore, in MR-DC, a wireless bearer with an RLC bearer present only in the MCG may be called an MCG bearer. Similarly, a wireless bearer with an RLC bearer present only in the SCG may be called an SCG bearer. Finally, in a DC, a wireless bearer with an RLC bearer present in both the MCG and SCG may be called a split bearer.

[0101] When a terminal device configures MR-DC, the bearer types of SRB1 and SRB2 established and / or configured by the terminal device may be MN-terminated MCG bearer and / or MN-terminated split bearer. Also, when a terminal device configures MR-DC, the bearer type of SRB3 established and / or configured by the terminal device may be SN-terminated SCG bearer. Also, when a terminal device configures MR-DC, the bearer type of DRB established and / or configured by the terminal device may be any of all bearer types.

[0102] For RLC bearers established and / or configured by a terminal device in a cell group composed of E-UTRA, the RLC entities established and / or configured by the terminal device may be E-UTRA RLC. Similarly, for RLC bearers established and / or configured by a terminal device in a cell group composed of NR, the RLC entities established and / or configured by the terminal device may be NR RLC. When a terminal device configures EN-DC, the PDCP entities established and / or configured by the terminal device for MN-terminated MCG bearers may be either E-UTRA PDCP or NR PDCP. Furthermore, when a terminal device configures EN-DC, the PDCPs established and / or configured by the terminal device for other bearer types of wireless bearers, namely MN-terminated split bearers, MN-terminated SCG bearers, SN-terminated MCG bearers, SN-terminated split bearers, and SN-terminated SCG bearers, may be NR PDCP. Furthermore, when a terminal device configures NGEN-DC, NE-DC, or NR-DC, the PDCP entities that the terminal device establishes and / or configures for wireless bearers of all bearer types may be NR PDCPs.

[0103] In NR, the DRB established and / or configured by the terminal device may be associated with one PDU session. The terminal device may establish and / or configure one SDAP entity for one PDU session. The SDAP entity, PDCP entity, RLC entity, and logical channel established and / or configured by the terminal device may be established and / or configured by the terminal device through RRC signaling received from the base station device.

[0104] Regardless of whether the terminal device configures MR-DC or not, a network configuration where the master node is eNB102 and the core network is EPC104 may be called E-UTRA / EPC. Similarly, a network configuration where the master node is eNB102 and the core network is 5GC110 may be called E-UTRA / 5GC. Furthermore, a network configuration where the master node is gNB108 and the core network is 5GC110 may be called NR or NR / 5GC. When the terminal device does not configure MR-DC, the master node mentioned above may refer to the base station device that communicates with the terminal device.

[0105] The flow of RRC signaling transmitted and received between the terminal device and the base station device will be described. Figure 4 is a diagram showing an example of the flow of procedures for various settings in the RRC according to this embodiment. Figure 4 is an example of the flow when RRC signaling is sent from the base station device (eNB102, and / or gNB108) to the terminal device (UE122).

[0106] In Figure 4, the base station device creates an RRC message (step S400). The creation of an RRC message by the base station device may be performed to distribute system information (SI) or paging messages. Alternatively, the creation of an RRC message by the base station device may be performed to send an RRC signaling to a specific terminal device to perform an action. The actions to be performed by a specific terminal device may include, for example, security settings, RRC connection reconfiguration, handover to a different RAT, suspension of an RRC connection, and release of an RRC connection. RRC connection reconfiguration may include, for example, control of radio bearers (establish, change, release, etc.), control of cell groups (establish, add, change, release, etc.), measurement settings, handover, and security key updates. The creation of an RRC message by the base station device may also be performed in response to an RRC signaling sent from a terminal device. Responses to RRC signaling transmitted from terminal devices may include, for example, responses to RRC setup requests, RRC reconnection requests, and RRC restart requests. RRC messages contain various informational notifications and configuration information (parameters). These parameters may be called fields and / or information elements and may be described using the ASN.1 (Abstract Syntax Notation One) notation scheme.

[0107] In Figure 4, the base station device then transmits the created RRC signaling to the terminal device (step S402). The terminal device then performs any necessary processing, such as configuration, according to the received RRC signaling (step S404). The terminal device that has performed the processing may transmit a response RRC signaling to the base station device (not shown).

[0108] RRC signaling may be used for purposes other than those mentioned above.

[0109] In MR-DC, the RRC signaling for SCG-side settings (cell group settings, wireless bearer settings, measurement settings, etc.) may be transmitted between the master node and the terminal device using the master node's RRC. For example, in EN-DC or NGEN-DC, the RRC signaling for NR may be included in the form of a container within the RRC signaling for E-UTRA transmitted and received between eNB102 and UE122. Similarly, in NE-DC, the RRC signaling for E-UTRA may be included in the form of a container within the RRC signaling for NR transmitted and received between gNB108 and UE122. RRC signaling for SCG-side settings may be transmitted and received between the master node and the secondary node.

[0110] Furthermore, not only when using MR-DC, the RRC signaling for E-UTRA transmitted from eNB102 to UE122 may include RRC signaling for NR, and the RRC signaling for NR transmitted from gNB108 to UE122 may include RRC signaling for E-UTRA.

[0111] Next, handover in LTE and NR will be described. Handover may be a process in which a terminal device in an RRC connection state changes the serving cell from a source SpCell to a target SpCell. Handover may be part of the mobility control performed by RRC. In a terminal device, handover may be performed based on RRC signaling that instructs handover received from a base station device. RRC signaling that instructs handover may be a message regarding the reconfiguration of the RRC connection that includes an information element (e.g., a MobilityControlInfo information element or a ReconfigurationWithSync information element) that includes a parameter that instructs handover. The MobilityControlInfo information element may be called a mobility control setting information element, mobility control setting, or mobility control information. The ReconfigurationWithSync information element may be called a synchronized reconfiguration information element. In addition to or instead of the above, the RRC signaling that indicates a handover may be a message indicating the movement of another RAT to a cell (e.g., MobilityFromEUTRACommand or MobilityFromNRCommand). The handover may be triggered by the RRC. The conditions under which a terminal device can perform a handover may also include some or all of the following conditions: AS security is activated, the terminal device has established an SRB2, and at least one DRB is established.

[0112] An example of parameters included in a message regarding the reconfiguration of an RRC connection is described below. Figure 7 is an example of an ASN.1 description representing a field and / or information element included in a message regarding the reconfiguration of an RRC connection in NR, as shown in Figure 4. Not limited to Figure 7, in the examples of ASN.1 in this embodiment, <omitted> indicates that other information is omitted, not part of the ASN.1 notation. Information elements may also be omitted where there is no <omitted> notation. In this embodiment, the example of ASN.1 represents an example of the parameters of the RRC signaling in this embodiment, and other names or notations may be used. Furthermore, in order to avoid making the explanation complicated, only examples of the main information closely related to this embodiment are shown. In each embodiment, parameters described in ASN.1 may all be expressed as information elements without distinguishing between fields, information elements, etc. Also, in each embodiment, the fields and / or information elements described in ASN.1 included in the RRC signaling may be referred to as information, or in addition to or instead referred to as parameters. The message regarding the reconfiguration of the RRC connection may be the RRC reconfiguration message in NR. Furthermore, the message regarding the reconfiguration of the RRC connection may be the RRC connection reconfiguration message in E-UTRA.

[0113] In Figure 7, the message regarding the reconfiguration of the RRC connection may include an information element used for security key updates (MasterKeyUpdate information element). The MasterKeyUpdate information element may include some or all of the following: an information element indicating whether or not to derive a new security key (keySetChangeIndicator information element), an information element indicating NCC parameters (nextHopChainingCount information element), and an information element indicating fields for transferring UE-specific NAS layer information between the network and the terminal device (nas-Container information element).

[0114] In Figure 7, the message regarding the reconfiguration of the RRC connection may include information elements (CellGroupConfig information elements) used for setting, changing, releasing, etc., of the NR's MCG or SCG cell groups. The message regarding the reconfiguration of the RRC connection may independently include CellGroupConfig information elements for MCG configuration and CellGroupConfig information elements for SCG configuration. The CellGroupConfig information elements may also be called cell group configuration information elements or cell group configurations.

[0115] The CellGroupConfig information element may include a cellGroupId information element as identifier information for identifying this cell group.

[0116] The CellGroupConfig information element may include the RLC-BearerConfig information element as information used to configure the RLC entity.

[0117] The CellGroupConfig information element may include the MAC-CellGroupConfig information element, which is used to set the MAC parameters for that cell group.

[0118] The CellGroupConfig information element may include the PhysicalCellGroupConfig information element, which is used to set the PHY(L1) parameters specific to that cell group.

[0119] The CellGroupConfig information element may include a SpCellConfig information element, which is used to set parameters for the SpCell of that cell group. The SpCellConfig information element may also be called a SpCell setting information element or SpCell setting.

[0120] The CellGroupConfig information element may include a SCellConfig information element for each SCell, which is used to set parameters for one or more SCells in that cell group. The SCellConfig information element may also be called a SCell setting information element or SCell setting.

[0121] The MAC-CellGroupConfig information element may include a TAG-Config information element as information used to set parameters related to TAGs. The TAG-Config information element may include identifiers (TAG-Id) of one or more TAGs set by the terminal device and the value of the time adjustment timer corresponding to the identifier of that TAG.

[0122] The SpCellConfig information element may include the ServingCellConfig information element as information used to set terminal device-specific (UE specific) parameters related to SpCell. Similarly, the SCellConfig information element may include the ServingCellConfig information element as information used to set terminal device-specific (UE specific) parameters related to SCell. The CellGroupConfig information element may include a ServingCellConfig information element for each serving cell to set terminal device-specific parameters related to SpCell and each SCell. Each ServingCellConfig information element may include a TAG identifier (TAG-Id) indicating which TAG within the cell group the serving cell belongs to. In addition, the ServingCellConfig information element may include not only terminal device-specific parameters but also cell-specific parameters.

[0123] Each ServingCellConfig information element may include initialDownlinkBWP, which indicates the BWP-DownlinkDedicated information element, as a terminal device-specific setting for the initial downlink BWP. The BWP-DownlinkDedicated information element is also referred to as a downlink BWP-specific setting. In addition to or instead of this, each ServingCellConfig information element may include some or all of the first active downlink BWP identifier (firstActiveDownlinkBWP-Id), the BWP inactivity timer (bwp-InactivityTimer), and the default downlink BWP identifier (defaultDownlinkBWP-Id).

[0124] The ServingCellConfig information element, used for setting terminal device-specific parameters for each SCell, may include a DormantBWP-Config information element as a setting for a dormant BWP for the SCell. The DormantBWP-Config information element is also referred to as the dormant BWP setting. For example, the DormantBWP-Config information element may include a dormant BWP identifier (dormantBWP-Id).

[0125] The SCellConfig information element may include an RRC parameter (sCellState) that indicates whether or not SCell is activated when SCell is configured. sCellState is also referred to as the SCell state setting. For example, if the SCellConfig information element includes sCellState, or alternatively, if the RRC entity of the terminal device sets the sCellState included in the SCellConfig information element to activated, the MAC entity of the terminal device may activate the SCell, or in addition or alternatively, the RRC layer of the terminal device may configure its lower layers (MAC entity, etc.) to consider that the SCell is activated. In addition or alternatively, for example, if the SCellConfig information element does not include sCellState, the MAC entity of the terminal device may deactivate the SCell, or in addition or alternatively, the RRC layer of the terminal device may configure its lower layers (MAC entity, etc.) to consider that the SCell is deactivated.

[0126] The ServingCellConfig information element for setting terminal-specific parameters for each SCell that the terminal device has not set PUCCH may include an SCell inactivity timer.

[0127] Each ServingCellConfig information element may include an UplinkConfig information element as an uplink setting. The UplinkConfig information element is also referred to as the uplink setting. The UplinkConfig information element may include initialUplinkBWP, which indicates a BWP-UplinkDedicated information element, as a terminal device-specific setting for the initial uplink BWP. The BWP-UplinkDedicated information element is also referred to as the uplink BWP-dedicated setting. In addition to or instead of the above, the UplinkConfig information element may include a firstActiveUplinkBWP identifier (firstActiveUplinkBWP-Id).

[0128] The SpCellConfig information element may include a ReconfigurationWithSync information element, which contains information necessary for the process of synchronous reconfiguration from a source SpCell to a target SpCell. The ReconfigurationWithSync information element may be the aforementioned synchronous reconfiguration information element. If the MCG's SpCellConfig information element includes a ReconfigurationWithSync information element, the process of synchronous reconfiguration to the target SpCell may be a handover. If the SCG's SpCellConfig information element includes a ReconfigurationWithSync information element, the process of synchronous reconfiguration to the target SpCell may be a PSCell addition or PSCell modification.

[0129] The ReconfigurationWithSync information element and the SCellConfig information element may include a ServingCellConfigCommon information element, which is used to set cell-specific parameters for a serving cell. The ServingCellConfigCommon information element may include parameters typically obtained from the cell's SSB, MIB, or one or more SIBs when a terminal device accesses the cell from an idle state.

[0130] The ReconfigurationWithSync information element may include, for example, information on the C-RNTI value used in the cell group of the target SpCell. The ReconfigurationWithSync information element may also include, for example, information on the parameters of timer T304, as described later. The ReconfigurationWithSync information element may also include the RACH-ConfigDedicated information element, for example, information necessary for executing a contention-based random access (CBRA) procedure or a contention-free random access (CFRA) procedure in the target SpCell. The RACH-ConfigDedicated information element is also referred to as the RACH-dedicated setting.

[0131] Figure 8 is an example of an ASN.1 description representing the fields and / or information elements related to the ServingCellConfigCommon information element, which are included in the SCellConfig information element and the ReconfigurationWithSync information element within the SpCellConfig information element, as shown in Figure 7.

[0132] The ServingCellConfigCommon information element may include the physical cell identifier (physCellId) of that cell.

[0133] The ServingCellConfigCommon information element may include a DownlinkConfigCommon information element, which provides cell-specific (cell-common) downlink parameters. The DownlinkConfigCommon information element is also referred to as the common downlink setting.

[0134] The ServingCellConfigCommon information element may include the UplinkConfigCommon information element, which provides cell-specific (cell-common) uplink parameters. The UplinkConfigCommon information element is also referred to as the common uplink setting.

[0135] The ServingCellConfigCommon information element may contain the value of N_{TA,offset} which is applied to all uplink transmissions in that cell.

[0136] The DownlinkConfigCommon information element may include the FrequencyInfoDL information element as basic information about the downlink carrier and transmission on that downlink carrier. For example, the FrequencyInfoDL information element may include SSB frequency information.

[0137] The DownlinkConfigCommon information element may include initialDownlinkBWP, which indicates the BWP-DownlinkCommon information element, as the initial downlink BWP setting for that cell. In addition to or instead of this, the DownlinkConfigCommon information element may include initialDownlinkBWP-RedCap, which indicates the BWP-DownlinkCommon information element used by one or more performance-limited terminals (RedCap UEs) instead of initialDownlinkBWP. The BWP-DownlinkCommon information element is also referred to as the common downlink BWP setting.

[0138] The BWP-DownlinkCommon information element may include BWP information elements as information for the terminal device to set generic parameters of BWP.

[0139] The BWP-DownlinkCommon information element may include the PDCCH-ConfigCommon information element, which provides information for the terminal device to set cell-specific parameters for the PDCCH of this BWP. The PDCCH-ConfigCommon information element is also referred to as the PDCCH common settings.

[0140] The BWP-DownlinkCommon information element may include the PDSCH-ConfigCommon information element, which provides information for the terminal device to set cell-specific parameters for the PDSCH of this BWP. The PDSCH-ConfigCommon information element is also referred to as the PDSCH common settings.

[0141] The PDCCH-ConfigCommon information element may include a SearchSpaceZero information element as information for the terminal device to set the parameters of the common search space (CSS) #0. This SearchSpaceZero information element may be included in the PDCCH-ConfigCommon information element only if the BWP is the initial downlink BWP.

[0142] The PDCCH-ConfigCommon information element may include a ControlResourceSetZero information element as information for a terminal device to set the parameters of the common CORESET#0 used in one or more common search spaces and one or more UE-specific search spaces. This ControlResourceSetZero information element may be included in the PDCCH-ConfigCommon information element only if the BWP is the initial downlink BWP.

[0143] The PDCCH-ConfigCommon information element may include a ControlResourceSet information element as information for the terminal device to set additional common CORESET parameters.

[0144] The PDCCH-ConfigCommon information element may contain a list of information elements (SearchSpace information elements) (commonSearchSpaceList) that indicate one or more additional CSS settings.

[0145] The PDCCH-ConfigCommon information element may include information (searchSpaceSIB1) indicating which CSS setting in the commonSearchSpaceList corresponds to the search space setting for system information (SIB1).

[0146] The PDCCH-ConfigCommon information element may include information (searchSpaceOtherSystemInformation) indicating which CSS setting in the commonSearchSpaceList corresponds to the search space setting for system information (SIB2 and later).

[0147] The PDCCH-ConfigCommon information element may include information (pagingSearchSpace) indicating which CSS setting in commonSearchSpaceList is responsible for setting the search space for paging messages.

[0148] The UplinkConfigCommon information element may include the FrequencyInfoUL information element, which sets the absolute uplink frequency and lists multiple virtual carriers specific to each subcarrier. For example, the FrequencyInfoUL information element may include information indicating the maximum transmit power.

[0149] The UplinkConfigCommon information element may include initialUplinkBWP, which indicates the BWP-UplinkCommon information element, as the initial uplink BWP setting for that cell. In addition to or instead of this, the UplinkConfigCommon information element may include initialUplinkBWP-RedCap, which indicates the BWP-UplinkCommon information element used by one or more performance-limited terminals (RedCap UEs) instead of initialUplinkBWP. The BWP-UplinkCommon information element is also referred to as the common uplink BWP setting.

[0150] The BWP-UplinkCommon information element may include BWP information elements as information for the terminal device to set generic parameters of the BWP.

[0151] The BWP-UplinkCommon information element may include the PUCCH-ConfigCommon information element, which provides information for the terminal device to set cell-specific parameters for PUCCH of this BWP. The PUCCH-ConfigCommon information element is also referred to as the PUCCH common settings.

[0152] The BWP-UplinkCommon information element may include the PUSCH-ConfigCommon information element, which provides information for the terminal device to set cell-specific parameters for the BWP's PUSCH function. The PUSCH-ConfigCommon information element is also referred to as the PUSCH common settings.

[0153] The BWP-UplinkCommon information element may include the RACH-ConfigCommon information element as information for terminal devices to set cell-specific random access parameters. The RACH-ConfigCommon information element is also referred to as the RACH common setting.

[0154] Note that each of the above information elements may include other information besides the information described.

[0155] This document describes the RRC reconfiguration procedure. The RRC reconfiguration procedure is a procedure for a terminal device to modify an RRC connection based on a message regarding the reconfiguration of the RRC connection. The purpose of the RRC reconfiguration procedure may be some or all of the following (A) to (F): (A) Establishing, modifying, and / or releasing a wireless bearer; (B) Performing a synchronized reconfiguration; (C) Setting up, modifying, and / or releasing a measurement; (D) Adding, modifying, and / or releasing SCells and cell groups; (E) Adding, modifying, and / or releasing a conditional handover (CHO) setting; (F) Adding, modifying, and / or releasing a conditional PSCell change (CPC) or conditional PSCell addition (CPA) setting.

[0156] The base station equipment (Network) may initiate the RRC reconfiguration procedure for a terminal device in the RRC_CONNECTED state. Note that "the base station equipment initiates the RRC reconfiguration procedure for a terminal device" can be rephrased as "the base station equipment sends a message to the terminal device regarding the reconfiguration of the RRC connection."

[0157] When a terminal device receives a message regarding the resetting of an RRC connection, or when performing a conditional reset (CHO, CPA, or CPC), it may perform some or all of the following RRP processes (A) through (D): (RRP processes) (A) If the message regarding the resetting of an RRC connection includes an MCG cell group setting, the cell group setting is performed using that cell group setting. In addition, if the cell group setting includes a SpCell setting that includes a synchronized reset information element, a synchronized reset is performed. (B) If the message regarding the resetting of an RRC connection includes an SCG cell group setting, the cell group setting is performed using that cell group setting. In addition, if the cell group setting includes a SpCell setting that includes a synchronized reset information element, a synchronized reset is performed. (C) If the message regarding the resetting of an RRC connection includes information about a conditional reset, the conditional reset setting process is performed using that conditional reset information. (D) To transmit using the new settings, an RRC reconfiguration completion message is submitted to the lower layers of the terminal device (PHY, MAC, etc.).

[0158] The terminal device may perform some or all of the following RWS processes (A) through (G) in order to execute synchronized reset. "Execute synchronized reset" may be rephrased as "Perform synchronized reset" or "Trigger synchronized reset". (RWS Process) (A) If this procedure is performed for an MCG, or if this procedure is performed for an SCG that has not been notified of deactivation in the RRC signaling of an E-UTRA or NR embedded in a message regarding the reset of the RRC connection, set the value of the timer T304 described below included in the synchronized reset information element and start the timer T304 for the corresponding SpCell. (B) If the synchronized reset information element includes a frequencyInfoDL information element, determine that the target SpCell is the cell indicated by the physical cell identifier included in the synchronized reset information element, which is at the SSB frequency indicated by the frequencyInfoDL information element. If the synchronized reset information element does not contain the frequencyInfoDL information element, it is determined that the target SpCell is a cell that is on the same SSB frequency as the source SpCell and is indicated by the physical cell identifier included in the synchronized reset information element. (C) Start downlink synchronization to the target SpCell. (D) If the timing information required for the random access procedure is not held, retrieve the MIB of the target SpCell. (E) Reset the MAC entity of the cell group to be reset with synchronization. (F) Apply the value of the new UE identifier (newUE-Identity) included in the synchronized reset information element as the C-RNTI for the cell group to be reset with synchronization. (G) Configure the lower layers of the RRC (PHY, etc.) according to the SpCell common settings.

[0159] Conditional reconfiguration is described below. The terminal device receives one or more conditional reconfiguration information elements from the network, and therefore, the terminal device sets candidate target SpCells associated with each conditional reconfiguration information element received from the network. The terminal device evaluates the state of the set candidate target SpCells. The terminal device performs the evaluation and applies one of the conditional RRC reconfiguration information elements included in the conditional reconfiguration information elements associated with one or more candidate target SpCells that satisfy the execution conditions. The terminal device may also maintain a list of entries (VarConditionalReconfig) described later for conditional reconfiguration.

[0160] Conditional resetting may be referred to as conditional handover when the candidate target SpCell is an MCG SpCell (i.e., a PCell). Alternatively, conditional resetting may be referred to as conditional PSCell addition and / or conditional PSCell modification when the candidate target SpCell is an SCG SpCell (i.e., a PSCell).

[0161] As part of the conditional reset configuration process, the terminal device may, upon receiving information regarding conditional resets (e.g., conditional reset information elements), perform a conditional reset if the information regarding conditional resets includes an attempt conditional reset information element (attemptCondReconfig), and if the selected cell in the RRC connection re-establishment procedure described later is a target candidate cell (e.g., candidate target SpCell) and the cell selection is the first cell selection after a conditional reset failure (e.g., expiration of timer T304).

[0162] As part of the conditional reset setting process, if the information regarding the conditional reset includes an entry deletion list (condReconfigToRemoveList), the terminal device may remove the conditional reset setting specified in the entry deletion list from the settings held by the terminal device. Specifically, if an entry identifier (condReconfigId) included in the entry deletion list is included in the list of entries held by the terminal device, the terminal device may delete the entry corresponding to the entry identifier from the list of entries held by the terminal device.

[0163] In the following explanation, the list of conditional reset entries held by the terminal device will also be simply referred to as the entry list. That is, unless otherwise specified, "entry list" in the following explanation refers to the list of conditional reset entries held by the terminal device. The conditional reset entry list may also be a variable named VarConditionalReconfig. The entry identifier will also be simply referred to as the entry identifier.

[0164] As part of the conditional reset configuration process, if the information regarding the conditional reset includes an entry addition / modification list (condReconfigToAddModList), the terminal device may add or modify the conditional reset settings included in the entry addition / modification list to the settings held by the terminal device. The entry addition / modification list may be a list of one or more conditional reset information elements. The terminal device may configure each entry with a conditional reset information element. The conditional reset information element may include an entry identifier, an execution condition, and a conditional RRC reset information element.

[0165] Specifically, if each entry identifier included in the entry addition / modification list exists in an entry in the entry list, the terminal device may perform the following processes (A) and / or (B): (A) If an entry included in the entry addition / modification list includes an execution condition (condExecutionCond), the execution condition of the entry in the entry list that matches the entry identifier of this entry is replaced with the execution condition included in the entry addition / modification list. (B) If an entry included in the entry addition / modification list includes a conditional RRC reconfiguration information element (condRRCReconfig), the conditional RRC reconfiguration information element of the entry list that matches the entry identifier of this entry is replaced with the conditional RRC reconfiguration information element included in the entry addition / modification list.

[0166] Furthermore, if an entry identifier included in the entry addition / modification list is not included in the entry list, the terminal device may add a new entry to the entry list corresponding to the entry identifier that is not included in the entry list.

[0167] The entry deletion list may be a list of one or more entry identifiers to be deleted. Each entry included in the entry addition / modification list may include an entry identifier, and in addition, may include execution conditions and / or conditional RRC reset information elements. Each entry may be associated with one of one or more candidate target SpCells. The entry identifier may be an identifier used to identify each entry of CHO, CPA, and CPC. The entry list may include one or more entries. Each entry may include one entry identifier, one or more execution conditions, and one conditional RRC reset information element. If the entry list held by the terminal device does not contain any entries, the terminal device may hold an empty list. The execution conditions may be conditions that must be met to trigger the execution of conditional reset. The conditional RRC reset information elements may be messages regarding the reset of the RRC connection that are applied when the execution conditions are met. The messages regarding the reset of the RRC connection may be messages used to connect to a candidate target SpCell.

[0168] A terminal device may evaluate the execution conditions of entries included in the entry list it holds. If the entry list held by the terminal device is empty or if it does not hold an entry list, it does not need to evaluate the execution conditions.

[0169] Conditional resetting may be performed by a terminal device evaluating the execution conditions of an entry in the entry list it holds, and if one or more execution conditions are met, applying a conditional RRC resetting information element contained in the entry containing those execution conditions. Applying a conditional RRC resetting information element may be performed by using that conditional RRC resetting information element to execute an RRC resetting procedure.

[0170] If there are multiple entries that satisfy the execution conditions, the terminal device may select one entry from among the multiple entries that satisfy the execution conditions and apply the conditional RRC reset information element of the selected entry.

[0171] If a MAC entity of a terminal device is requested to reset the MAC entity from a higher layer (e.g., RRC), it may perform some or all of the following processes MR (A) through (N). The MAC entity reset may simply be referred to as a MAC reset. If a MAC entity of a terminal device is requested to partially reset the MAC entity from a higher layer (e.g., RRC), it may perform some or all of the following processes MR (A) through (N). The partial reset of the MAC entity may simply be referred to as a partial MAC reset. The processes performed in a partial MAC reset may be processes in which only some of the processes performed in a MAC reset are performed. The processes performed in a partial MAC reset may be processes in which some of the processes performed in a MAC reset are not performed. The MAC entity of a terminal device may perform a MAC reset based on an instruction from the RRC entity of the terminal device to the MAC entity of the terminal device to perform a MAC reset. In addition to or instead of the above, the MAC entity of the terminal device may perform a partial MAC reset based on an instruction from the RRC entity of the terminal device to the MAC entity of the terminal device.

[0172] (Processing MR) (A) Initialize parameter Bj set by the terminal device for each logical channel to 0. (B) Stop all running timers except for some timers, including time adjustment timers. (C) Set the value of New Data Indicator (NDI) for all uplink HARQ processes to 0. (D) Stop any ongoing random access procedures. (E) Discard any explicitly signaled 4-step and 2-step RA type contention-free random access (CFRA) resources. (F) Flush the Msg3 buffer. (G) Flush the MSGA buffer. (H) Cancel any triggered Scheduling Request (SR) procedures. (I) Cancel any triggered Buffer Status Reporting (BSR) procedures. (J) Cancel any triggered Power Headroom Reporting (PHR) procedures. (K) Flushes the soft buffers of all downlink HARQ processes. (L) Cancels any triggered Beam Failure Reporting (BFRs). (M) Releases any Temporary C-RNTIs. (N) Resets all BFI_COUNTERs.

[0173] This section describes the RRC connection re-establishment procedure. The RRC connection re-establishment procedure is a procedure by which a terminal device re-establishes an RRC connection based on an RRC re-establishment message. The RRC connection re-establishment procedure may also be called the RRC re-establishment procedure. In the RRC connection re-establishment procedure, the terminal device may send an RRC re-establishment request message to the base station device (Network), and then, based on receiving an RRC re-establishment message from the base station device, determine that the RRC connection has been successfully re-established and send an RRC re-establishment complete message to the base station device. The order in which the terminal device determines that the RRC connection has been successfully re-established and sends the RRC re-establishment complete message to the base station device does not matter. Furthermore, a terminal device in the RRC_CONNECTED state may start the procedure in order to continue the RRC connection. Re-establishing the RRC connection is successful if the base station device can find a valid UE context and verify that it is the UE context held by the terminal device. Alternatively, if the UE context cannot be obtained, the base station device may respond with an RRC setup message.

[0174] When the terminal device initiates the RRC connection re-establishment procedure, it may perform some or all of the following RRI processes (A) to (C). (RRI processes) (A) Stop timer T304 if it is running. (B) If the terminal device has not set the attemptCondReconfig element, perform some or all of the following processes (B-1) to (B-5). (C) Perform cell selection, and if a suitable NR cell is selected, perform some or all of the following processes (C-1) to (C-2).

[0175] (B-1) Reset the MAC entity. (B-2) Release the SpCell configuration if configured by the terminal device. (B-3) Suspend all wireless bearers except SRB0. (B-4) Release one or more SCells of the MCG if configured by the terminal device. (B-5) Release the MR-DC if configured by the terminal device.

[0176] (C-1) Ensure that you have valid, up-to-date, and essential system information. (C-2) If cell selection is triggered by detection of MCG wireless link failure, MCG synchronous reconfiguration failure (i.e., expiration of timer T304), or mobility failure from NR, and the terminal device has set an attempt conditional reconfiguration information element (attemptCondReconfig), and the selected cell is one of the candidate cells for a synchronous reconfiguration information element included in the MCG conditional reconfiguration entry list (VarConditionalReconfig), then the terminal device applies the conditional RRC reconfiguration information element (condRRCReconfig) associated with the selected cell and performs some or all of the above-described RRP process; otherwise, some or all of the following processes (C-2-1) to (C-2-4) are performed; if the terminal device has set an attempt conditional reconfiguration information element (attemptCondReconfig), then some or all of the following processes (C-2-5) to (C-2-7) are performed.

[0177] (C-2-1) Apply the (multiple) default L1 parameter values ​​other than those provided in SIB1 as the values ​​for the corresponding physical layer specifications. (C-2-2) Apply the default MAC cell group configuration. (C-2-3) Apply the CCCH configuration. (C-2-4) Start sending the RRC re-establishment request message.

[0178] (C-2-5) Reset the MAC entity. (C-2-6) Release the SpCell configuration if the terminal device has configured it. (C-2-7) Release one or more SCells of the MCG if the terminal device has configured it.

[0179] The timer T304 described above may start when the terminal device receives a message regarding the reconfiguration of the RRC connection, which includes a synchronized reconfiguration information element, and may stop when the random access procedure on the SpCell corresponding to the synchronized reconfiguration information element is successfully completed. Also, when the timer T304 described above expires, the terminal device may start the RRC connection re-establishment procedure. In addition to or instead of this, the timer T304 described above may start when a lower layer (such as the MAC layer) notifies that the LTM cell switching process described below has been triggered, and / or when the LTM cell switching process is performed after cell selection. In addition to or instead of this, in the case of an LTM cell switching that does not involve the execution of a random access procedure, the timer T304 described above may stop for the same HARQ process when a PDCCH addressed to C-RNTI is received after the initial uplink transmission.

[0180] Now, let's explain the bandwidth portion (BWP).

[0181] A BWP may be part or all of the bandwidth of a serving cell. A BWP may also be called a Carrier BWP. A terminal device may configure one or more BWPs. A terminal device may configure a BWP using information contained in system information associated with a synchronization signal detected during an initial cell search. Alternatively, a BWP may be a frequency bandwidth associated with the frequency at which the initial cell search is performed. A terminal device may also receive a BWP from a base station device via RRC signaling (e.g., Dedicated RRC signaling) and configure the received BWP using RRC. A terminal device may also configure downlink BWPs (DL BWPs) and uplink BWPs (UL BWPs) separately. Alternatively, one or more uplink BWPs may be associated with one or more downlink BWPs. Furthermore, the mapping between the uplink BWP and the downlink BWP may be a default mapping, a mapping by RRC signaling (e.g., Dedicated RRC signaling), a mapping by physical layer signaling (e.g., downlink control information (DCI) notified via the downlink control channel), or a combination of these. In addition, the terminal device may set CORESET in the downlink BWP.

[0182] A BWP may consist of a group of consecutive Physical Resource Blocks (PRBs). Furthermore, a connected terminal device may set the parameters of each component carrier's BWP (one or more BWPs). The BWP parameters for each component carrier may include some or all of the following: (A) the type of cyclic prefix, (B) the subcarrier spacing, (C) the frequency position of the BWP (e.g., the starting position or center frequency position on the lower frequency side of the BWP) (the frequency position may be, for example, an ARFCN or an offset from a specific subcarrier of the serving cell. The unit of the offset may be in subcarrier units or resource block units. The terminal device may set both the ARFCN and the offset.), (D) the bandwidth of the BWP (e.g., the number of PRBs), (E) resource setting information for the control signals, and (F) the center frequency position of the SS block (the frequency position may be, for example, an ARFCN or an offset from a specific subcarrier of the serving cell. The unit of the offset may be in subcarrier units or resource block units. The terminal device may set both the ARFCN and the offset.). Additionally, resource setting information for the control signals may be included in the BWP settings for at least some or all of the PCell and / or PSCell.

[0183] A terminal device may perform transmission and reception using one or more configured BWPs, specifically the Active BWP. A terminal device may configure one or more BWPs in a single serving cell it is associated with. A terminal device may configure one or more BWPs configured for a single serving cell it is associated with so that, at any given time, a maximum of one uplink BWP and / or a maximum of one downlink BWP be the Active BWP. The downlink Active BWP is also referred to as the Active DL BWP. The uplink Active BWP is also referred to as the Active UL BWP. In addition, any BWP that is not the Active BWP among the one or more configured by a terminal device may be referred to as the Inactive BWP.

[0184] Next, we will explain BWP activation / deactivation. BWP activation can mean activating a BWP, or activating an inactive BWP. BWP deactivation can mean deactivating a BWP, or inactivating an active BWP. BWP switching in a serving cell is used to activate an inactive BWP and deactivate an active BWP.

[0185] BWP switching is controlled by the MAC entity itself for a PDCCH indicating a downlink assignment or uplink grant, a BWP inactivity timer, RRC signaling, or the initiation of a random access procedure. The active BWP of a serving cell is indicated by the RRC or PDCCH.

[0186] Next, we will describe the BWP inactivity timer. For each activated serving cell in which a terminal device has set a BWP inactivity timer, the MAC entity performs (A) below. The BWP inactivity timer may also be named bwp-InactivityTimer. (A) If any of the following conditions (A-1) to (A-4) are met, the MAC entity performs (B) and (D) below. (A-1) The UE has set a default downlink BWP identifier (defaultDownlinkBWP-Id), the Active DL BWP is not the BWP indicated by defaultDownlinkBWP-Id, and the Active DL BWP is not the BWP indicated by dormantBWP-Id. (A-2) The UE is not a performance-limited terminal (RedCap UE), the UE has not set the default downlink BWP identifier (defaultDownlinkBWP-Id), the Active DL BWP is not initialDownlinkBWP, and the Active DL BWP is not the BWP indicated by the dormant BWP identifier (dormantBWP-Id). (A-3) The UE is a performance-limited terminal (RedCap UE), the UE has not set the default downlink BWP identifier (defaultDownlinkBWP-Id), the UE has not set the initial downlink BWP for performance-limited terminals (initialDownlinkBWP-RedCap), and the Active DL BWP is not initialDownlinkBWP. (A-4) The UE is a performance-limited terminal (RedCap UE), the UE has not set a default downlink BWP identifier (defaultDownlinkBWP-Id), the UE has set an initial downlink BWP for performance-limited terminals (initialDownlinkBWP-RedCap), and the Active DL BWP is not initialDownlinkBWP-RedCap.(B) If the Active BWP receives a PDCCH addressed to C-RNTI or CS-RNTI indicating a downlink assignment or uplink grant, or if the Active BWP receives a PDCCH addressed to C-RNTI or CS-RNTI indicating a downlink assignment or uplink grant, or if a MAC PDU is sent in a configured uplink grant, or if a MAC PDU is received in a configured downlink assignment, the MAC entity performs (C) below: (C) If no random access procedure associated with this serving cell is running, or if a running random access procedure associated with this serving cell is successfully completed by receiving a PDCCH addressed to C-RNTI, the MAC entity starts or restarts the BWP inactivity timer associated with the Active DL BWP. (D) If the BWP inactivity timer associated with the Active DL BWP expires, the MAC entity performs (E) below: (E) If the UE has set defaultDownlinkBWP-Id, the BWP switch is performed to the BWP indicated by defaultDownlinkBWP-Id; otherwise, the MAC entity performs (F) below. (F) If the UE is a performance-limited terminal (RedCap UE) and the UE has set an initial downlink BWP for performance-limited terminals (initialDownlinkBWP-RedCap), the BWP switch is performed to initialDownlinkBWP-RedCap; otherwise, the BWP switch is performed to initialDownlinkBWP.

[0187] Furthermore, if the MAC entity receives a PDCCH for BWP switching and switches the Active DL BWP, it performs the following (A): (A) If any of the following (A-1) to (A-4) are met, it starts or restarts the BWP inactivity timer associated with the Active DL BWP: (A-1) The UE has set a default downlink BWP identifier (defaultDownlinkBWP-Id), and the MAC entity switches to a downlink BWP that is not indicated in either defaultDownlinkBWP-Id or dormantBWP identifier (dormantBWP-Id). (A-2) The UE is not a performance-limited terminal (RedCap UE), the UE has not set a default downlink BWP identifier (defaultDownlinkBWP-Id), and the MAC entity switches to a downlink BWP that is not initialDownlinkBWP and is not indicated in dormantBWP identifier (dormantBWP-Id). (A-3) The UE is a performance-limited terminal (RedCap UE), the UE has not set the default downlink BWP identifier (defaultDownlinkBWP-Id), the UE has not set the initial downlink BWP for performance-limited terminals (initialDownlinkBWP-RedCap), and the MAC entity switches to a downlink BWP that is not initialDownlinkBWP. (A-4) The UE is a performance-limited terminal (RedCap UE), the UE has not set the default downlink BWP identifier (defaultDownlinkBWP-Id), the UE has set the initial downlink BWP for performance-limited terminals (initialDownlinkBWP-RedCap), and the MAC entity switches to a downlink BWP that is not initialDownlinkBWP-RedCap.

[0188] In each activated serving cell where the UE has configured a BWP, the MAC entity shall, if the BWP is activated (an Active BWP) and the Active DL BWP in that serving cell is not a dormant BWP, perform some or all of the following (A) through (H): (A) Send UL-SCH on that BWP. (B) If the UE has configured a PRACH occasion, send RACH (PRACH) on that BWP. (C) Monitor PDCCH on that BWP. (D) If the UE has configured PUCCH, send PUCCH on that BWP. (E) Report CSI on that BWP. (F) If the UE has configured SRS, send SRS on that BWP. (G) Receive DL-SCH on that BWP. (H) If any, initialize all suspended configured uplink grants of grant type 1 that the UE has configured in its Active BWP, according to the stored configuration.

[0189] If a BWP is activated (is an Active BWP) and the Active DL BWP in its serving cell is a dormant BWP, the MAC entity will perform some or all of the following (A) through (L): (A) Stop the BWP inactivity timer for this serving cell, if it is running. (B) Do not monitor PDCCH on that BWP. (C) Do not monitor PDCCH for that BWP. (D) Do not receive DL-SCH on that BWP. (E) Do not report CSI on that BWP, and report CSI for that BWP except aperiodic CSI. (F) Do not transmit SRS on that BWP. (G) Do not transmit UL-SCH on that BWP. (H) Do not transmit RACH on that BWP. (I) Do not transmit PUCCH on that BWP. (J) Clear all configured downlink assignments and / or all configured uplink grants of grant type 2 associated with that SCell. (K) Suspend all Grant Type 1 configured uplink grants associated with that SCell. (L) If a beam failure is detected, perform beam failure detection and beam failure recovery for that SCell.

[0190] If a BWP is deactivated, the MAC entity will perform some or all of the following (A) through (I): (A) Do not send UL-SCH on that BWP. (B) Do not send RACH on that BWP. (C) Do not monitor PDCCH on that BWP. (D) Do not send PUCCH on that BWP. (E) Do not report CSI on that BWP. (F) Do not send SRS on that BWP. (G) Do not receive DL-SCH on that BWP. (H) Clear all configured downlink assignments and / or all configured uplink grants of grant type 2 that the UE has set up on that BWP. (I) Suspend all configured uplink grants of grant type 1 on that Inactive BWP.

[0191] Next, we will describe the Central Unit (CU) and the Distributed Unit (DU). A Central Unit may be a logical node that hosts the RRC, SDAP, and PDCP layers of a base station device. A Distributed Unit may be a logical node that hosts the RLC, MAC, and PHY layers of a base station device. A Central Unit may control the operation of one or more Distributed Units. A single Distributed Unit may support one or more cells. A single cell may be supported by only one Distributed Unit. Some functions of the Central Unit may be implemented in the Distributed Units. Conversely, some functions of the Distributed Units may be implemented in the Central Units.

[0192] Next, Layer 1 / Layer 2 triggered mobility (L1 / L2-triggered mobility: LTM) in this embodiment will be described.

[0193] LTM may be a procedure in which the base station device switches the serving cell of a terminal device by a cell switching command signaled via MAC CE, based on one or more L1 measurement reports described later that the base station device receives from the terminal device. The cell switching command specifies an LTM candidate setting that the base station device has prepared in advance and provided to the terminal device via RRC signaling. The terminal device may apply the target setting in accordance with the cell switching command.

[0194] For example, the RRC layer of the terminal device may receive RRC signaling from the base station device, which includes one or more LTM candidate settings. The RRC layer of the terminal device may store the received one or more LTM candidate information elements. The MAC layer of the terminal device may also receive a cell switching command from the base station device via MAC CE. The RRC layer of the terminal device may apply a target setting in accordance with the cell switching command. The cell switching command may include a target setting identifier indicating the target setting. The MAC layer of the terminal device that has received the cell switching command may notify the RRC layer of the terminal device (a layer higher than the MAC layer) that the LTM cell switching procedure has been triggered and the target setting identifier. The RRC layer that has received notification from the MAC layer (a layer lower than the RRC layer) that the LTM cell switching procedure has been triggered and the target setting identifier may trigger the cell switching procedure and apply one of the one or more LTM candidate information elements identified by the target identifier. The target setting identifier may be an identifier used to identify a candidate LTM setting. The target setting may be a candidate LTM setting indicated by the target setting identifier. The cell switching command may be a command (MAC CE) that triggers the terminal device to perform an LTM cell switching procedure. The target identifier may be associated with a candidate LTM identifier described later.

[0195] In LTM, the base station equipment may determine the target setting based on a measurement report provided by the terminal equipment. The measurement report may be a CSI reporting transmitted by the terminal equipment via PUSCH. In addition to or instead, the measurement report may be a CSI reporting transmitted by the terminal equipment via PUCCH. In addition to or instead, the measurement report may be a measurement report message transmitted by the terminal equipment as RRC signaling. In addition to or instead, the measurement report may be measurement report information transmitted by the terminal equipment as MAC CE. The measurement report may also be other information.

[0196] MAC CE can also be referred to as Layer 2 signaling. Furthermore, the above measurements may be performed by Layer 1 (PHY layer), Layer 2 (MAC layer), and / or Layer 3 (RRC layer). Furthermore, the above measurement reports may be performed by Layer 1 (PHY layer), Layer 2 (MAC layer), and / or Layer 3 (RRC layer).

[0197] The cell switching command may be signaled by MAC CE. The MAC CE may also be called the LTM cell switching command MAC CE and may be used interchangeably with the term cell switching command. That is, sending and receiving a cell switching command may be rephrased as sending and receiving an LTM cell switching command MAC CE. The cell switching command may include multiple fields, and these multiple fields may include the following information, as well as other information: (a) a target setting identifier corresponding to the LTM candidate identifier (b) a TA command (c) an identifier indicating the TCI state in the target setting SpCell (target cell) (d) an identifier indicating the uplink TCI state in the target setting SpCell (target cell) (e) information indicating the existence of a CFRA resource (f) information indicating the uplink carrier that transmits the CFRA PRACH (g) a preamble index of the CFRA resource (h) information indicating the SSB used to determine the RACH occasion for transmitting the CFRA PRACH (i) information indicating the RACH occasion related to the SSB indicated in the information indicating the SSB

[0198] One or more LTM candidate information elements may be included in the LTM setting, and the LTM setting may be included in the RRC reset message. The RRC reset message may be RRC signaling. The LTM candidate information elements may include an LTM candidate identifier, an LTM candidate cell identifier, an LTM-SSB setting, an LTM candidate setting, an LTM full setting indicator, an early UL synchronization setting, an early SUL synchronization setting, an LTM reset decision identifier B, an LTM-UE reference TA measurement identifier B, and other information. The LTM candidate identifier is an identifier used to identify the LTM candidate setting and the LTM candidate information elements, and may be an information element named ltm-CandidateId. The LTM candidate cell identifier is an identifier indicating the physical cell identifier (PCI) of the SpCell of the setting included in the LTM candidate setting, and may be an information element named ltm-CandidatePCI. The LTM-SSB setting indicates the setting of the SS / PBCH block used for L1 measurement and TCI status, and may be an information element named ltm-SSB-Config. The LTM candidate setting is a setting that includes RRC resetting used to set up an LTM candidate cell, and may be an information element named ltm-CandidateConfig. The LTM complete setting indicator indicates whether the RRC resetting included in the LTM candidate setting is a complete setting, and may be an information element named ltm-ConfigComplete. The early UL synchronization setting is a setting used to execute an early UL synchronization procedure on the UL carrier, and may be an information element named ltm-EarlyUL-SyncConfig. The early SUL synchronization setting is a setting used to execute an early UL synchronization procedure on the SUL carrier, and may be an information element named ltm-EarlyUL-SyncConfigSUL. The LTM reset determination identifier B is an identifier used to determine whether an L2 reset is performed when an LTM cell switching procedure is triggered for an LTM candidate cell, and may be an information element named ltm-NoResetID.The LTM-UE criterion TA measurement identifier B is an identifier used to determine whether or not to perform a UE criterion TA measurement on an LTM candidate cell, and may be an information element named ltm-UE-MeasuredTA-ID.

[0199] The LTM configuration may include an LTM reference configuration, an LTM candidate configuration release list, an LTM candidate configuration add / modify list, an LTM reset decision identifier A, an LTM-UE criterion TA measurement identifier A, an LTM-CSI resource configuration release list, an LTM-CSI resource configuration add / modify list, and other information. The LTM reference configuration is a configuration used to configure a reference configuration for LTM, and may be an information element named ltm-ReferenceConfiguration. The LTM candidate configuration release list is a list indicating LTM candidate configurations to be released, and may be an information element named ltm-CandidateToReleaseList. The LTM candidate configuration release list may be a list of LTM candidate identifiers corresponding to the LTM candidate configurations to be released. The LTM candidate configuration add / modify list is a list of LTM candidate configurations to be added and / or modified, and may be an information element named ltm-CandidateToAddModList. The LTM reset decision identifier A is an identifier used to determine whether an L2 reset is performed when an LTM cell switching procedure is triggered for an LTM candidate cell, and may be an information element named ltm-ServingCellNoResetID. The LTM-UE-based TA measurement identifier A is an identifier used to determine whether or not to perform a UE-based TA measurement on an LTM candidate cell, and may be an information element named ltm-ServingCellUE-MeasuredTA-ID. The LTM-CSI resource configuration release list is a list indicating the LTM-CSI resource configurations to be released, and may be an information element named ltm-CSI-ResourceConfigToReleaseList. The LTM-CSI resource configuration release list may be a list of LTM-CSI resource configuration identifiers corresponding to the LTM-CSI resource configurations to be released. The LTM-CSI resource configuration add / modify list is a list of LTM-CSI resource configurations to be added and / or modified, and may be an information element named ltm-CSI-ResourceConfigToAddModList.An LTM-CSI resource configuration may be a configuration that defines a group of one or more CSI resources for one or more LTM candidate configurations. Each LTM-CSI resource configuration may be identified by an LTM-CSI resource configuration identifier.

[0200] A terminal device that has received an RRC reset message including an LTM setting may perform the following actions based on the received LTM setting: (A) If the received LTM setting includes an LTM reset decision identifier A, and the current UE variable-LTM reset decision identifier includes an LTM reset decision identifier A, the terminal device may replace the value of the LTM reset decision identifier A included in the UE variable-LTM reset decision identifier with the received LTM reset decision identifier A; or, if the received LTM setting includes an LTM reset decision identifier A, and the current UE variable-LTM reset decision identifier does not include an LTM reset decision identifier A, the terminal device may store the received LTM reset decision identifier A in the UE variable-LTM reset decision identifier. (B) If the received LTM setting includes LTM-UE reference TA measurement identifier A, and the current UE variable-LTM-UE reference TA measurement identifier includes LTM-UE reference TA measurement identifier A, the value of LTM-UE reference TA measurement identifier A included in the UE variable-LTM-UE reference TA measurement identifier may be replaced with the received LTM-UE reference TA measurement identifier A. If the received LTM setting includes LTM-UE reference TA measurement identifier A, and the current UE variable-LTM-UE reference TA measurement identifier does not include LTM-UE reference TA measurement identifier A, the received LTM-UE reference TA measurement identifier A may be stored in the UE variable-LTM-UE reference TA measurement identifier. (C) If the received LTM setting includes an LTM candidate setting release list, the terminal device that received the LTM candidate setting release list described below may be operated. (D) If the received LTM setting includes an LTM candidate setting addition / modification list, the terminal device that received the LTM candidate setting addition / modification list described below may be operated. The aforementioned UE variable -LTM reset determination identifier may be used to store the identifier of a serving cell, which serves as a criterion for the terminal device to determine whether or not an L2 reset is necessary during the LTM cell switching procedure. This UE variable may be named VarLTM-ServingCellNoResetID.The aforementioned UE variable-LTM-UE reference TA measurement identifier may be used to store the identifier of a serving cell that serves as the criterion for the terminal device to determine whether or not UE reference TA measurement is necessary, and may be a UE variable named VarLTM-ServingCellUE-MeasuredTA-ID. Note that a UE variable may be a variable stored internally in the terminal device.

[0201] A terminal device that has received the LTM candidate setting addition / modification list performs the following processing for each LTM candidate identifier included in the LTM candidate setting addition / modification list: (A) If it determines that the current settings of the terminal device include an LTM candidate information element containing an LTM candidate identifier with the same value as the LTM candidate identifier, it resets the corresponding LTM candidate information element (included in the terminal device settings) according to the received LTM candidate information element. Otherwise (i.e., it does not determine that the current settings of the terminal device include an LTM candidate information element containing an LTM candidate identifier with the same value as the LTM candidate identifier), it may add the received LTM candidate information element to the settings of the terminal device. (B) If the LTM candidate information element containing the received LTM candidate identifier contains the LTM-UE criterion TA measurement identifier B, and further, (C) if it is determined that the value of the LTM-UE criterion TA measurement identifier B is equal to the value of the LTM-UE criterion TA measurement identifier A contained in the UE variable-LTM-UE criterion TA measurement identifier, the lower layer may be notified that a UE criterion TA measurement is set up for this LTM candidate information element. If not (i.e., if it is not determined that the value of the LTM-UE criterion TA measurement identifier B is equal to the value of the LTM-UE criterion TA measurement identifier A contained in the UE variable-LTM-UE criterion TA measurement identifier), the lower layer may be notified that a UE criterion TA measurement is not set up for this LTM candidate information element.

[0202] Upon receiving the LTM candidate setting release list, the terminal device performs the following processing on each LTM candidate identifier included in the LTM candidate setting release list: (A) It may delete the LTM candidate information element corresponding to the LTM candidate identifier.

[0203] Furthermore, if NR-DC is configured on the terminal device, the terminal device can receive two independent LTM settings. That is, it can receive (1) an LTM setting associated with the MCG contained in an RRC reset message received via SRB1, and (2) an LTM setting associated with the SCG contained in an RRC reset message received via SRB3 or embedded in an RRC reset message received via SRB1. If the terminal device receives two independent LTM settings, the terminal device may maintain the two independent LTM settings, maintain two independent UE variable-LTM-UE reference TA measurement identifiers, maintain two independent UE variable-LTM reset decision identifiers, and perform all procedures independently for each LTM setting, UE variable-LTM-UE reference TA measurement identifier and UE variable-LTM reset decision identifier unless otherwise explicitly instructed.

[0204] In LTM, some or all of the following mobility scenarios (A) through (J) may be supported, and other mobility scenarios may also be supported: (A) Intra-gNB-DU mobility (B) Intra-gNB-CU inter-gNB-DU mobility (C) Inter-frequency mobility (including mobility to inter-frequency cells that are not the current serving cell) (D) Intra-frequency mobility (E) PCell changes in terminal equipment where CA and DC are not configured (F) PCell and one or more SCell changes in terminal equipment where CA is configured (G) PCell and MCG SCell(s), PSCell and SCG SCell(s) changes, MN-independent changes in terminal equipment where DC is configured (H) Inter-cell beam management (not considered as a prerequisite for using Layer 1 / Layer 2 triggered mobility) (I) Inter-gNB-CU mobility (J) Conditional mobility

[0205] Next, we will describe the cell selection method in this embodiment.

[0206] Cell selection in the RRC_IDLE state is described below. The principle of PLMN selection in NR may be based on the 3GPPPLMN selection principle. Cell selection is required at least during transitions from RM-DEREGISTERED to RM-REGISTERED, from CM-IDLE to CM-CONNECTED, and from CMCONNECTED to CM-IDLE, and may be based on the following principles: (1) The NAS layer of UE122 identifies one selected PLMN and one or more equivalent PLMNs. (2) Cell selection is always based on the CD-SSB located on the synchronization raster. (2-1) The UE searches the NR frequency band and identifies the strongest cell for each carrier frequency according to the CD-SSB, then reads the system information broadcast of the cell and identifies the PLMN of the cell. (2-1-1) The UE may search each carrier sequentially (initial cell selection), or alternatively, it may shorten the search by using stored information (stored information cell selection). (3) The UE attempts to identify a suitable cell. If it cannot identify a suitable cell, it attempts to identify an acceptable cell. If a suitable cell is found, or if only acceptable cells are found, the UE camps to that cell and begins the cell reselection procedure. (3-1) A suitable cell may be a cell whose measured cell attributes meet the cell selection criteria. The PLMN of the cell may be a selected PLMN, a registered PLMN, or an equivalent PLMN. In addition, the cell may not be barred or reserved and may not be part of a tracking area on the list of "forbidden tracking areas for roaming". (3-2) An acceptable cell may be a cell whose measured cell attributes meet the cell selection criteria and which is not barred.

[0207] Next, cell selection will be described. Cell selection may be performed based on the initial cell selection or the stored information cell selection. In the initial cell selection, UE122 may (1) scan all RF channels in the NR band to the extent possible to find a suitable cell, (2) at each frequency, search for the strongest cell (in the case of shared spectrum channel access, UE122 may search for the next strongest cell), and (3) if a suitable cell is found, select that cell. In the stored information cell selection, UE122 may (1) require stored frequency information and, as optional additional information, require previously received measurement control information elements or cell parameter information from previously detected cells, (2) if a suitable cell is found, select that cell, and (3) if a suitable cell is not found, initiate the initial cell selection procedure. A suitable cell may be a cell whose measured cell attributes satisfy the cell selection criteria. The PLMN of the cell may be a selected PLMN, a registered PLMN, or an equivalent PLMN. In addition, the cell may not be barred or reserved, and may not be part of a tracking area on the list of "forbidden tracking areas for roaming."

[0208] The cell selection may be triggered by a wireless link failure in the MCG, by a synchronous reconfiguration failure of the MCG, by the RRC connection re-establishment procedure, or based on other procedures or conditions. The UE122 may start timer T311 during the RRC connection re-establishment procedure. During cell selection while timer T311 is running, if the UE122 has selected an appropriate cell, it may retain valid and up-to-date system information, stop timer T311, or perform other actions. The cell selection may also be referred to as the cell selection procedure.

[0209] Next, Random Access in this embodiment will be described. The Random Access Procedure may be triggered by a RACH-based LTM cell switch or by the execution of a Conditional LTM. The following two types of random access procedures may be supported: (1) 4-step RA type with MSG1 (2) 2-step RA type with MSGA Both types of random access procedures may support contention-based random access (CBRA) and contention-free random access (CFRA). The terminal device may select the type of random access at the start of the random access procedure according to the network settings as follows: (a) When no CFRA resource is configured, either the 2-step RA type or the 4-step RA type may be selected using the RSRP threshold. (b) When a CFRA resource for the 4-step RA type is configured, the terminal device may perform the 4-step RA type. (c) When a CFRA resource for the 2-step RA type is configured, the terminal device may perform the 2-step RA type. Base station equipment does not need to configure CFRA resources for 4-step and CFRA resources for 2-step at the same time within a given Bandwidth Part (BWP). CFRA with 2-step RA type is configured solely for handover support.

[0210] Next, the 4-step RA type will be described. MSG1 (Message 1, Msg1) in the 4-step RA type may consist of a PRACH preamble. After MSG1 is forwarded, the terminal device may monitor the response from the base station device in a configured window. In CFRA, if a dedicated preamble for transmitting MSG1 is allocated by the base station device and a random access response is received from the base station device, the terminal device may terminate the random access procedure. In CBRA, if a random access response is received, the terminal device may transmit MSG3 (Message 3, Msg3) using a scheduled UL grant and monitor the contention resolution. If the contention resolution is not successful after (re)transmission of MSG3, the terminal device may transmit MSG1 again.

[0211] Next, the 2-step RA type will be described. The MSGA in the 2-step RA type may include a PRACH preamble and a PUSCH payload. After transmitting the MSGA, the terminal device may monitor the response from the base station device within the configured window. In CFRA, a dedicated preamble and a PUSCH resource may be configured for MSGA transmission, and if a response is received from the base station device, the terminal device may terminate the random access procedure. In CBRA, if a response is received from the base station device and contention resolution is successful, the terminal device may terminate the random access procedure. If a fallback indication is received in MSGB, the terminal device may perform MSG3 transmission using the UL grant scheduled in the fallback indication and monitor the contention resolution. If contention resolution is unsuccessful after (re)transmission of MSG3, the terminal device may return to transmitting the MSGA.

[0212] If the 2-step RA type random access procedure does not complete after multiple MSGA transmissions, the terminal device may be configured to transition to CBRA with the 4-step RA type. In the random access procedure for early uplink TA acquisition (early UL TA acquisition) for LTM candidate cells, a CFRA triggered by a PDCCH order may be used. In the said early uplink TA acquisition (early UL TA acquisition) random access procedure, the terminal device does not need to transmit an MSG1 or monitor the response to the MSG1. In the said early uplink TA acquisition (early UL TA acquisition) random access procedure, the terminal device may retransmit an MSG1 in accordance with instructions from the base station device to support UE power ramping.

[0213] If a contention-free Random Access Resource for a Random Access Procedure is provided and a non-zero Msg1 repetition number is indicated, the terminal device may assume that the Msg1 repetition is available and that the repetition number available for the latest Random Access procedure is the indicated Msg1 repetition number.

[0214] If the Random Access Preamble index is explicitly indicated by the base station equipment and the SS-RSRP of the indicated SSB is higher than the rsrp-Threshold, the terminal device may set the Random Access Preamble index in PREAMBLE_INDEX and select the SSB indicated by the SS / PBCH index.

[0215] The terminal device may determine the next available PRACH occasion associated with a selected SSB permitted by the constraints given by the PRACH Mask index.

[0216] The MAC layer of the terminal device may instruct the MAC layer to send a Random Access Preamble with the selected PRACH occasion, associated RA-RNTI, PREAMBLE_INDEX, and PREAMBLE_RECEIVED_TARGET_POWER.

[0217] Based on the above description, various embodiments will be explained. Note that any processes omitted in the following description may be replaced by the processes described above.

[0218] Figure 5 is a block diagram showing the configuration of the terminal device (UE122) in this embodiment. Note that, to avoid complicating the explanation, Figure 5 only shows the main components closely related to this embodiment.

[0219] The UE122 shown in Figure 5 consists of a receiving unit 500 that receives control information (DCI, MAC CE, RRC signaling, etc.) from a base station device, a processing unit 502 that processes according to the parameters included in the received control information, and a transmitting unit 504 that transmits control information (UCI, RRC signaling, etc.) to the base station device. The base station device mentioned above may be an eNB102 or a gNB108. Furthermore, the processing unit 502 may include some or all of the functions of various layers (for example, the physical layer, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, and NAS layer). That is, the processing unit 502 may include some or all of the physical layer processing unit, MAC layer processing unit, RLC layer processing unit, PDCP layer processing unit, SDAP layer processing unit, RRC layer processing unit, and NAS layer processing unit. In addition to or instead of the above, the receiver 500 may include some or all of the functions of various layers (e.g., physical layer, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, and NAS layer). That is, the receiver 500 may include some or all of the physical layer receiver, MAC layer receiver, RLC layer receiver, PDCP layer receiver, SDAP layer receiver, RRC layer receiver, and NAS layer receiver.

[0220] Figure 6 is a block diagram showing the configuration of the base station device in this embodiment. To avoid a complicated explanation, Figure 6 shows only the main components closely related to this embodiment. The base station device mentioned above may be eNB102 or gNB108.

[0221] The base station device shown in Figure 6 consists of a transmitting unit 600 that transmits control information (DCI, MAC CE, RRC signaling, etc.) to the UE 122, a processing unit 602 that creates control information (DCI, RRC signaling including parameters, etc.) and transmits it to the UE 122, causing the processing unit 502 of the UE 122 to perform processing, and a receiving unit 604 that receives control information (UCI, RRC signaling, etc.) from the UE 122. Furthermore, the processing unit 602 may include some or all of the functions of various layers (for example, the physical layer, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, and NAS layer). That is, the processing unit 602 may include some or all of the physical layer processing unit, MAC layer processing unit, RLC layer processing unit, PDCP layer processing unit, SDAP layer processing unit, RRC layer processing unit, and NAS layer processing unit. In addition to or instead of the above, the transmitter 600 may include some or all of the functions of various layers (e.g., physical layer, MAC layer, RLC layer, PDCP layer, SDAP layer, RRC layer, and NAS layer). That is, the transmitter 600 may include some or all of the physical layer transmitter, MAC layer transmitter, RLC layer transmitter, PDCP layer transmitter, SDAP layer transmitter, RRC layer transmitter, and NAS layer transmitter.

[0222] An example of the processing of the terminal device (UE122) in this embodiment will be explained using Figure 9. In this embodiment, the processing unit 502 of UE122 may include an RRC processing unit for processing RRC, a PDCP processing unit for processing PDCP, an RLC processing unit for processing RLC, a MAC processing unit for processing MAC, and a PHY processing unit for processing PHY.

[0223] Figure 9 shows an example of the processing of UE122 in this embodiment. UE122 makes a conditional judgment (step S900) and acts based on the judgment (step S902).

[0224] UE122 may receive a MAC CE from the base station equipment. The MAC CE may include information indicating one or more TAs associated with one or more candidate cells and information regarding one or more Random Access Resources. In addition to or instead, the MAC CE may include information for identifying one or more candidate cells. In addition to or instead, UE122 may receive an RRC message including one of the LTM settings which includes information regarding one or more Random Access Resources associated with one or more candidate cells. The information indicating the TA may be a Timing Advance Command, a TA value, a 12-bit value, or any other value. The information regarding the Random Access Resource may include all or some of the following: (a) Random Access Preamble index (b) SS / PBCH index (c) PRACH Mask index (d) Repetition number

[0225] The UE122 may, based on the fact that cell selection has been triggered and the cell selected in the cell selection is determined to be the candidate cell, perform Random Access on the candidate cell using information about the Random Access Resource associated with the candidate cell. In addition to or instead of this, the UE122 may, based on the fact that the MCG has determined that cell selection was triggered by a radio link failure, perform Random Access on the candidate cell using information about the Random Access Resource associated with the candidate cell. In addition to or instead of this, the UE122 may, based on the fact that the MCG has determined that cell selection was triggered by a re-configuration with sync failure in an LTM cell switch procedure triggered by instructions from a lower layer (such as the MAC layer), perform Random Access on the candidate cell using information about the Random Access Resource associated with the candidate cell. In addition to or instead of this, the UE122 may, based on the fact that attemptLTM-Switch is set to the UE122, perform Random Access on the candidate cell using information about the Random Access Resource.

[0226] As demonstrated by the example of this embodiment described above, CFRA can be executed using LTM candidate settings, enabling faster connection recovery.

[0227] Furthermore, unless otherwise specified, the term "wireless bearer" in the above description may refer to a DRB, an SRB, or both a DRB and an SRB.

[0228] Furthermore, in the above explanation, terms such as "user plane," "user plane protocol," and "user plane interface" may be used interchangeably.

[0229] Furthermore, in the above explanation, expressions such as "terminal device variable," "terminal variable," and "variable" may be interchangeable.

[0230] Furthermore, unless otherwise specified, the serving cell change described above may refer to a change in a Layer 1 or Layer 2 serving cell.

[0231] Furthermore, in the above explanation, expressions such as "provided," "signaled," and "selected" may be interchangeable.

[0232] Furthermore, in the above explanation, expressions such as "LTM candidate target identifier" and "LTM candidate target entry identifier" may be interchangeable.

[0233] Furthermore, in the above explanation, expressions such as "to be notified" and "to be pointed out" may be used interchangeably.

[0234] Furthermore, in the above explanation, expressions such as "link," "correspond," and "associate" may be used interchangeably.

[0235] Furthermore, in the above explanation, expressions such as "included," "included," and "was included" may be interchangeable.

[0236] Furthermore, in the above explanation, "the aforementioned..." may be replaced with "the aforementioned...".

[0237] Furthermore, in the above explanation, expressions such as "it has been confirmed that...", "it is set that...", and "it includes..." can be used interchangeably.

[0238] Furthermore, in the above explanation, expressions such as "beam judged to meet the conditions," "beam judged to have met the conditions," "beam that meets the conditions," and "beam that met the conditions" may be interchanged with each other, and expressions such as "beam judged not to meet the conditions," "beam judged not to have met the conditions," "beam that does not meet the conditions," and "beam that did not meet the conditions" may also be interchanged with each other.

[0239] Furthermore, in the above explanation, expressions such as "measured quantity," "measured item," "measurement result," "measurement result of measured quantity," and "measurement result of measured item" may be interchangeable.

[0240] Furthermore, in the above explanation, expressions such as "the condition satisfies the measured quantity of a certain beam" and "a certain beam satisfies the condition" may be interchanged with each other.

[0241] Furthermore, in the above explanation, expressions such as "include in MAC CE" and "set in MAC CE field" can be used interchangeably.

[0242] Furthermore, in the above explanation, "prioritize A over B" can be rephrased as "prioritize A before B."

[0243] Furthermore, in the examples of processes or process flows described above, some or all of the steps may not be executed. Also, in the examples of processes or process flows described above, the order of the steps may differ. Also, in the examples of processes or process flows described above, some or all of the processes within each step may not be executed. Also, in the examples of processes or process flows described above, the order of the processes within each step may differ. Furthermore, in the above description, "perform B based on the fact that A is true" may be rephrased as "perform B." That is, "performing B" may be performed independently of "being true A."

[0244] Furthermore, in the above explanation, "A may be replaced with B" may include not only replacing A with B, but also replacing B with A. Also, in the above explanation, if it states "C may be D" and "C may be E", it may also include "D may be E". Also, in the above explanation, if it states "F may be G" and "G may be H", it may also include "F may be H".

[0245] Furthermore, in the above explanation, if condition "A" and condition "B" are contradictory, condition "B" may be expressed as an "other" condition of condition "A".

[0246] Furthermore, in the above explanation, expressions such as "set A to the MAC CE field," "include A to the MAC CE field," and "include A in MAC CE" may be used interchangeably. Also, in the above explanation, expressions such as "MAC CE contains A," "A is set to MAC CE," "MAC CE contains A in its field," and "MAC CE has A in its field" may be used interchangeably.

[0247] The program running on the device according to this embodiment may be a program that controls the Central Processing Unit (CPU), etc., to make the computer function in order to realize the functions of this embodiment. The program or the information handled by the program is temporarily loaded into volatile memory such as Random Access Memory (RAM) during processing, or stored in non-volatile memory such as flash memory or a Hard Disk Drive (HDD), and read, modified, and written by the CPU as needed.

[0248] Furthermore, some parts of the apparatus in the above-described embodiment may be implemented using a computer. In that case, the program for implementing this control function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be loaded into a computer system and executed. The term "computer system" here refers to a computer system built into the apparatus, and includes hardware such as an operating system and peripheral devices. The "computer-readable recording medium" may be any of the following: a semiconductor recording medium, an optical recording medium, a magnetic recording medium, etc.

[0249] Furthermore, "computer-readable recording media" may include those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or communication lines such as telephone lines, as well as those that hold programs for a certain period of time, such as volatile memory inside computer systems that act as servers or clients in such cases. In addition, the above-mentioned programs may be for the purpose of realizing some of the functions described above, and may also be programs that can realize the above-mentioned functions in combination with programs already recorded in the computer system.

[0250] Furthermore, each functional block or feature of the apparatus used in the embodiments described above may be implemented or executed by an electrical circuit, typically an integrated circuit or a combination of integrated circuits. Electrical circuits designed to perform the functions described herein may include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or combinations thereof. The general-purpose processor may be a microprocessor, or alternatively, the processor may be a conventional processor, controller, microcontroller, or state machine. The general-purpose processor, or each of the aforementioned circuits, may consist of digital or analog circuits. Also, if advances in semiconductor technology lead to the emergence of integrated circuit technologies that replace current integrated circuits, it may be possible to use integrated circuits based on such technologies.

[0251] It should be noted that this embodiment is not limited to the embodiments described above. Although the embodiments describe an example of a device, this embodiment is not limited to this and can be applied to stationary or non-movable electronic devices installed indoors or outdoors, such as terminal devices or communication devices for AV equipment, kitchen equipment, cleaning and washing machines, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0252] Although this embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of this embodiment are also included. Furthermore, this embodiment can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this embodiment. In addition, configurations in which elements described in the above embodiment that produce similar effects are substituted for each other are also included.

[0253] One aspect of the present invention can be used, for example, in communication systems, communication equipment (e.g., mobile phone devices, base station devices, wireless LAN devices, or sensor devices), integrated circuits (e.g., communication chips), or programs.

[0254] 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 Receiver 502, 602 Processing Unit 504, 600 Transmitter

Claims

1. A terminal device that communicates with a base station device, comprising a receiving unit and a processing unit, wherein the receiving unit receives a MAC CE from the base station device that includes one Random Access Resource associated with one candidate cell, and the processing unit, based on the fact that cell selection is triggered and that the cell selected in the cell selection is determined to be the candidate cell, performs Random Access on the candidate cell using the Random Access Resource.

2. A base station device that communicates with a terminal device, comprising: a transmitting unit that transmits a MAC CE to the terminal device; and a processing unit, wherein the processing unit includes a Random Access Resource associated with one candidate cell in the MAC CE, and transmits the MAC CE to the terminal device, thereby causing the terminal device to perform Random Access on the candidate cell using the Random Access Resource, based on the determination that cell selection has been triggered and that the cell selected in the cell selection is the candidate cell.

3. A method implemented in a terminal device that communicates with a base station device, the method comprising: receiving a MAC CE from the base station device that includes one Random Access Resource associated with one candidate cell; triggering cell selection; and, based on the determination that the cell selected in the cell selection is the candidate cell, performing Random Access on the candidate cell using the Random Access Resource.

Images