Terminal device, base station device, and method

Abstract

A terminal device that communicates with a base station device, comprising: a receiving unit that receives an RRC reconfiguration message including a first setting related to a radio bearer using DAPS (Dual Active Protocol Stack) from the base station device; and a processing unit that performs settings according to the RRC reconfiguration message. When the first timer expires, no radio link failure of the source primary cell is detected, and the first setting is made for any radio bearer, the processing unit releases the setting of the target primary cell, resets the MAC of the target primary cell, discards all data of the PDCP entity of the SRB of the source primary cell, discards all data of the RLC entity of the SRB of the source primary cell, restarts the suspended SRB in the source primary cell, and sends an RRC message to the base station device for notifying that the DAPS handover has failed.

Description

Technical Field

[0001] The present invention relates to a terminal device, a base station device, and a method.

[0002] This application claims priority to Japanese Patent Application No. 2019-205414 filed in Japan on November 13, 2019, the content of which is incorporated herein by reference. Background Art

[0003] In the 3rd Generation Partnership Project (3GPP), research has been conducted on radio access methods and radio networks for cellular mobile communications (hereinafter referred to as "Long Term Evolution (LTE: registered trademark)" or "Evolved Universal Terrestrial Radio Access (EUTRA)") and the core network (hereinafter, "Evolved Packet Core (EPC)"). EUTRA is also referred to as E-UTRA.

[0004] In addition, in 3GPP, as radio access methods and radio network technologies for the fifth-generation cellular system, technical research and standardization have been carried out on LTE-Advanced Pro, which is an extended technology of LTE, and NR (New Radio technology), which is a new radio access technology (Non-Patent Document 1). In addition, research has also been conducted on 5GC (5th Generation Core Network) as the core network for the fifth-generation cellular system (Non-Patent Document 2).

[0005] Prior Art Documents

[0006] Non-Patent Documents

[0007] Non-Patent Document 1: 3GPP RP-170855, "Work Item on New Radio (NR) Access Technology"

[0008] Non-Patent Document 2: 3GPP TS 23.501 v15.3.0, "System Architecture for the 5G System; Stage 2"

[0009] Non-Patent Document 3: 3GPP TS 36.300, v15.3.0, "Evolved Universal Terestrial Radio Access (E-UTRA) and Evolved Universal Terestrial Radio Access Network (E-UTRAN); Overall description; Stage 2"

[0010] Non-Patent Document 4: 3GPP TS 36.331 v15.4.0, "Evolved Universal Terestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specifications"

[0011] Non-Patent Document 5: 3GPP TS 36.323 v15.3.0, "Evolved Universal Terestrial Radio Access (E-UTRA); Packet Data Convergence Protocol (PDCP) specification"

[0012] Non-Patent Document 6: 3GPP TS 36.322 v15.3.0, "Evolved Universal Terestrial Radio Access (E-UTRA): Radio Link Control (RLC) protocol specification"

[0013] Non-Patent Document 7: 3GPP TS 36.321 v15.3.0, "Evolved Universal Terestrial Radio Access (E-UTRA); Medium Access Control (MAC) protocol specification"

[0014] Non-Patent Document 8: 3GPP TS 37.340v 15.3.0, "Evolved Universal Terestrial Radio Access (E-UTRA) and NR; Multi-Connectivity; Stage 2"

[0015] Non - Patent Document 9: 3GPP TS 38.300 v15.3.0, "NR; NR and NG - RAN Overall description; Stage 2"

[0016] Non - Patent Document 10: 3GPP TS 38.331 v15.4.0, "NR; Radio Resource Control (RRC); Protocol specifications"

[0017] Non - Patent Document 11: 3GPP TS 38.323 v15.3.0, "NR; Packet Data Convergence Protocol (PDCP) specification"

[0018] Non - Patent Document 12: 3GPP TS 38.322 v15.3.0, "NR; Radio Link Control (RLC) protocol specification"

[0019] Non - Patent Document 13: 3GPP TS 38.321 v15.3.0, "NR; Medium Access Control (MAC) protocol specification"

[0020] Non - Patent Document 14: 3GPP TS 23.401 v15.0.0, "General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E - UTRAN) access"

[0021] Non - Patent Document 15: 3GPP TS 23.502 v15.3.0, "Procedure for 5G System; Stage 2"

[0022] Non - Patent Document 16: 3GPP TS 37.324 v15.1.0, "NR; Service Data Adaptation Protocol (SDAP) specification"

[0023] Non-Patent Document 17: 3GPP Draft_Report_vl.doc, "Report of 3GPP TSG RAN2#105 meeting, Athens, Greece" http: / / www.3gpp.org / ftp / TSG_RAN / WG2_RL2 / TSGR2_105 / Report / Draft_Report_v1.zip

[0024] Non-Patent Document 18: 3GPP RP-181544, "Revised WID: Even further mobility enhancement in E-UTRAN"

[0025] Non-Patent Document 19: 3GPP RP-181433, "New WID: NR mobility enhancements"

[0026] Non-Patent Document 20: 3GPP R2-1901364, "Detail for non-split bearer option for simultaneous connectivity"

[0027] Non-Patent Document 21: 3GPP TS 33.401 v15.9.0, "3GPP System Architecture Evolution (SAE); Security architecture"

[0028] Non-Patent Document 22: 3GPP TS 33.501 v15.6.0, "Security architecture and procedures for 5G System" Summary of the Invention

[0029] Problems to be Solved by the Invention

[0030] As one of the technical studies on LTE, a mechanism for further expanding the existing LTE mobility extension technology has been studied. Moreover, in the technical study of NR, a mechanism for expanding the existing NR mobility technology has also been studied (Non-Patent Documents 18 and 19). These studies mainly include: research on a technology (RUDI: Reduce User Data Interruption) that makes the interruption of the transmission and reception of user data approach 0 ms when moving between cells (during handover) in the connection between the base station device and the terminal device; and research on improving the robustness of handover (Handover robustness improvements).

[0031] In RUDI, a mechanism in which two protocol stacks coexist for one cell group has been studied, but detailed actions of the terminal for efficiently controlling mobility have not been studied.

[0032] One aspect of the present invention has been completed in view of the above problems, and one of its objects is to provide a terminal device, a base station device, and a method capable of efficiently controlling mobility.

[0033] Technical Solution

[0034] To achieve the above object, one aspect of the present invention adopts the following solution. That is, a terminal device that communicates with a base station device, the terminal device includes: a receiving unit that receives an RRC (Radio Resource Control) reconfiguration message including a first setting related to a radio bearer using DAPS (Dual Active Protocol Stack) from the base station device; and a processing unit that makes settings according to the RRC reconfiguration message. When a first timer expires, no radio link failure of the source primary cell is detected, and the first setting has been made for any radio bearer, the processing unit releases the setting of the target primary cell, resets the MAC (Medium Access Control) of the target primary cell, discards all data of the PDCP (Packet Data Convergence Protocol) entity of the SRB (Signaling Radio Bearer) of the source primary cell, discards all data of the RLC (Radio Link Control) entity of the SRB of the source primary cell, restarts the suspended SRB in the source primary cell, and sends an RRC message to the base station device for notifying the case where the DAPS handover has failed.

[0035] In addition, a solution of the present invention is a base station device that communicates with a terminal device. The base station device includes: a transmission unit that transmits an RRC (Radio Resource Control) reconfiguration message including a first setting related to a radio bearer of an application DAPS (Dual Active Protocol Stack) to the terminal device; and a processing unit that causes the terminal device to perform settings according to the RRC reconfiguration message. When a first timer expires, no radio link failure of a source primary cell is detected, and the first setting is performed for any radio bearer, the processing unit causes the terminal device to release the setting of a target primary cell, reset the MAC (Medium Access Control) of the target primary cell, discard all data of the PDCP (Packet Data Convergence Protocol) entity of the SRB (Signaling Radio Bearer) of the source primary cell, discard all data of the RLC (Radio Link Control) entity of the SRB of the source primary cell, restart the suspended SRB in the source primary cell, and send an RRC message for notifying the base station device of the failure of DAPS handover.

[0036] It should be noted that these inclusive or specific solutions can be implemented by a system, a device, a method, an integrated circuit, a computer program, or a recording medium, or can be implemented by any combination of a system, a device, a method, an integrated circuit, a computer program, and a recording medium.

[0037] Advantageous Effects

[0038] According to a solution of the present invention, efficient mobility processing can be achieved between a terminal device and a base station device. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic diagram of a communication system according to each embodiment of the present invention.

[0040] Figure 2 is a protocol stack diagram of the UP and CP of a terminal device and a base station device in E-UTRA according to each embodiment of the present invention.

[0041] Figure 3 is a protocol stack diagram of the UP and CP of a terminal device and a base station device in NR according to each embodiment of the present invention.

[0042] Figure 4It is a diagram showing an example of the procedure of various settings in RRC208 and / or RRC308 of each embodiment of the present invention.

[0043] Figure 5 It is a block diagram showing the configuration of the terminal device of each embodiment of the present invention.

[0044] Figure 6 It is a block diagram showing the configuration of the base station device of each embodiment of the present invention.

[0045] Figure 7 It is a diagram showing an example of the process related to handover in EUTRA of each embodiment of the present invention.

[0046] Figure 8 It is a diagram showing an example of the process related to handover in NR of each embodiment of the present invention.

[0047] Figure 9 It is a diagram showing an example of the start and stop conditions of each timer of the embodiment of the present invention.

[0048] Figure 10 It is a diagram showing an example of the mobilityControlInfo information element of the embodiment of the present invention.

[0049] Figure 11 It is a diagram showing another example of the mobilityControlInfo information element of the embodiment of the present invention.

[0050] Figure 12 It is a diagram showing an example of the synchronization reconfiguration information element of the embodiment of the present invention.

[0051] Figure 13 It is a diagram showing another example of the synchronization reconfiguration information element of the embodiment of the present invention.

[0052] Figure 14 It is a diagram showing an example of the ASN.1 description included in the message related to the reconfiguration of the RRC connection in NR of the embodiment of the present invention.

[0053] Figure 15 It is a diagram showing an example of the ASN.1 description included in the message related to the reconfiguration of the RRC connection in E-UTRA of the embodiment of the present invention.

[0054] Figure 16 It is a diagram showing an example of the procedure of process A of the embodiment of the present invention.

[0055] Figure 17This is a diagram showing an example of the process of Process B according to an embodiment of the present invention.

[0056] Figure 18 This is a diagram showing an example of the process of Process C according to an embodiment of the present invention.

[0057] Figure 19 This is a diagram showing an example of the process of Process H according to an embodiment of the present invention.

[0058] Figure 20 This is an example of an ASN.1 description of a parameter for setting whether to apply make-before-break switching to a radio bearer according to each embodiment of the present invention.

[0059] Figure 21 This is a diagram showing another example of an ASN.1 description of a parameter for setting whether to apply make-before-break switching to a radio bearer according to each embodiment of the present invention.

[0060] Figure 22 This is a diagram showing another example of the process of Process E according to an embodiment of the present invention.

[0061] Figure 23 This is a diagram showing another example of the process of Process B according to an embodiment of the present invention.

[0062] Figure 24 This is a diagram showing another example of the process of Process LA according to an embodiment of the present invention.

[0063] Figure 25 This is a diagram showing an example of a processing method of UE122 according to each embodiment of the present invention.

[0064] Figure 26 This is a diagram showing another example of a processing method of UE122 according to each embodiment of the present invention. Detailed Embodiments

[0065] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0066] LTE (and LTE-A Pro) and NR can be defined as different Radio Access Technologies (RATs). In addition, NR can be defined as a technology included in LTE. LTE can be defined as a technology included in NR. In addition, LTE that can be connected to NR through Multi Radio Dual Connectivity can be distinguished from existing LTE. In addition, LTE with a 5GC core network can be distinguished from existing LTE with an EPC core network. This embodiment can be applied to NR, LTE, and other RATs. In the following description, terms related to LTE and NR are used for explanation, but it can also be applied to other technologies using other terms. In addition, in this embodiment, the term referred to as E-UTRA can be replaced with the term referred to as LTE, and the term referred to as LTE can be replaced with the term referred to as E-UTRA.

[0067] Figure 1 It is a schematic diagram of the communication system of each embodiment of the present invention.

[0068] E-UTRA 100 is a radio access technology described in Non-Patent Document 3, etc., and includes a cell group (CG) composed of one or more frequency bands. eNB (E-UTRAN Node B) 102 is a base station device of E-UTRA 100. EPC (Evolved Packet Core) 104 is a core network described in Non-Patent Document 14, etc., and is designed as a core network for E-UTRA 100. Interface 112 is an interface between eNB 102 and EPC 104, and there are a control plane (CP) through which control signals pass and a user plane (UP) through which its user data passes.

[0069] NR 106 is a radio access technology described in Non-Patent Document 9, etc., and includes a cell group (CG) composed of one or more frequency bands. gNB (g Node B) 108 is a base station device of NR 106. 5GC 110 is a core network described in Non-Patent Document 2, etc., and is designed as a core network for NR 106, but can also be used as a core network for E-UTRA 100 having a function of connecting to 5GC 110. Hereinafter, E-UTRA 100 may include E-UTRA 100 having a function of connecting to 5GC 110.

[0070] Interface 114 is the interface between eNB 102 and 5GC 110. Interface 116 is the interface between gNB 108 and 5GC 110. Interface 118 is the interface between gNB 108 and EPC 104. Interface 120 is the interface between eNB 102 and gNB 108. Interface 124 is the interface between EPC 104 and 5GC 110. Interfaces 114, 116, 118, 120, and 124, etc. can be interfaces that are only through the CP or only through the UP, or through both the CP and the UP. In addition, sometimes interfaces 114, 116, 118, 120, and 124, etc. may not exist according to the communication system provided by the communication operator.

[0071] UE 122 is a terminal device corresponding to any one or all of E-UTRA 100 and NR 106. As described in any one or all of Non-Patent Document 3 and Non-Patent Document 9, when UE 122 is connected to the core network via any one or all of E-UTRA 100 and NR 106, a logical path called a radio bearer (RB) is established between UE 122 and any one or all of E-UTRA 100 and NR 106. The radio bearer for the CP is called a signaling radio bearer (SRB), and the radio bearer for the UP is called a data radio bearer (DRB). Each RB is assigned an RB identifier (RB Identity or RB ID) and is identified as unique. The SRB is called an SRB identifier (SRB Identity or SRB ID) with the RB identifier, and the DRB is called a DRB identifier (DRB Identity or DRB ID) with the RB identifier.

[0072] As described in Non-Patent Document 3, when the core network to which UE 122 is connected is EPC 104, each DRB already established between UE 122 and any one or all of E-UTRA 100 and NR 106 is further uniquely associated with each EPS (Evolved Packet System) bearer within EPC 104. Each EPS bearer is assigned an EPS bearer identifier (Identity or ID) and is identified as unique. In addition, for the data passing through the same EPS bearer, the same QoS is guaranteed.

[0073] As described in Non-Patent Document 9, when the core network to which the UE 122 is connected is the 5GC 110, one or more DRBs already established between the UE 122 and any one or all of the E-UTRA 100 and the NR 106 are further associated with one of the PDU (Packet Data Unit) sessions to be established within the 5GC 110. One or more QoS flows exist in each PDU session. Each DRB may be mapped to one or more QoS flows existing within the associated PDU session, or may not be mapped to any QoS flow. Each PDU session is identified by a PDU session identifier (Identity or ID). In addition, each QoS flow is identified by a QoS flow identifier. In addition, the same QoS is guaranteed for data passing through the same QoS flow.

[0074] Neither any one or all of the PDU session and the QoS flow exist in the EPC 104, nor does the EPS bearer exist in the 5GC 110. In other words, when the UE 122 is connected to the EPC 104, the UE 122 has information on the EPS bearer, and when the UE 122 is connected to the 5GC 110, the UE 122 has information on any one or all of the PDU session and the QoS flow.

[0075] Figure 2 It is a protocol stack diagram of the UP and CP of the terminal device and the base station device in the E-UTRA radio access layer of each embodiment of the present invention.

[0076] Figure 2 (A) of is a protocol stack diagram of the UP used when the UE 122 communicates with the eNB 102 in the E-UTRA 100.

[0077] The PHY (Physical layer) 200 is a radio physical layer that provides a transmission service to the upper layer using a physical channel. The PHY 200 is connected to the upper MAC (Medium Access Control layer) 202 described later through a transport channel. Data moves between the MAC 202 and the PHY 200 via the transport channel. Data is transmitted and received between the PHYs of the UE 122 and the eNB 102 via a radio physical channel.

[0078] MAC202 is the Medium Access Control layer that maps multiple logical channels to multiple transport channels. MAC202 is connected to the upper-layer RLC (Radio Link Control layer) 204 described later through the logical channel. Logical channels are roughly classified according to the type of information transmitted, and are divided into a control channel for transmitting control information and a traffic channel for transmitting user information. MAC202 has functions such as controlling PHY200 for discontinuous reception / transmission (DRX / DTX), performing a random access process, notifying information on transmission power, and performing HARQ control (Non-Patent Document 7).

[0079] RLC204 is the Radio Link Control layer that segments the data received from the upper-layer PDCP (Packet Data Convergence Protocol Layer) 206 described later, adjusts the data size so that the lower layer can appropriately transmit the data. In addition, RLC200 also has a function for guaranteeing the QoS (Quality of Service) requested by each data. That is, RLC204 has functions such as retransmission control of data (Non-Patent Document 6).

[0080] PDCP206 is the Packet Data Convergence Protocol layer for efficiently transmitting user data such as IP packets (IP Packets) in the radio section. PDCP206 may have a header compression function for compressing unnecessary control information. In addition, PDCP206 may also have a data encryption function. (Non-Patent Document 5).

[0081] It should be noted that the data processed in MAC202, RLC204, and PDCP206 are respectively referred to as MAC PDU (Protocol Data Unit), RLC PDU, and PDCP PDU. In addition, the data transferred from the upper layer to MAC202, RLC204, PDCP206 or the data transferred to the upper layer are respectively referred to as MAC SDU (Service Data Unit), RLC SDU, and PDCP SDU.

[0082] In addition, to distinguish between data use and control use, PDCP PDUs may also be referred to as PDCP DATA PDUs (PDCP data PDUs) and PDCP CONTROL PDUs (PDCP control PDUs), respectively. In addition, to distinguish between data use and control use, RLC PDUs may also be referred to as RLC DATA PDUs (RLC data PDUs) and RLC CONTROL PDUs (RLC control PDUs), respectively.

[0083] Figure 2 The (B) of Figure 2 is a protocol stack diagram of the CP used when the UE 122 communicates with the eNB 102 and the MME (Mobility Management Entity: mobility management entity), which is a logical node that provides functions such as authentication and mobility management, in the E-UTRA 100.

[0084] In the protocol stack of the CP, in addition to PHY200, MAC202, RLC204, and PDCP206, there are also RRC (Radio Resource Control layer) 208 and NAS (non-Access Stratum) 210. RRC208 is responsible for, in addition to handling the establishment, re-establishment, suspension, and resume of RRC connections, reconfiguring RRC connections, such as setting up, changing, and releasing radio bearers (RBs) and cell groups, and controlling logical channels, transport channels, and physical channels. It also performs settings for handovers and measurements. An RB can be divided into a signaling radio bearer (SRB) and a data radio bearer (DRB). The SRB can be used as a path for transmitting RRC messages as control information. The DRB can be used as a path for transmitting user data. The settings of each RB can be carried out between the RRC208 of the eNB102 and the UE122. In addition, the part of the RB composed of the RLC204 and the logical channel can also be referred to as an RLC bearer (Non-Patent Document 4). In addition, for the NAS layer that transports signals between the MME and the UE122, some or all of the layers of PHY200, MAC202, RLC204, PDCP206, and RRC208 that transport signals and data between the UE122 and the eNB102 can be regarded as the AS (Access Stratum) layer (AS layer).

[0085] The functional classification of MAC202, RLC204, PDCP206, and RRC208 described above is an example, and it is also possible not to implement some or all of the functions. In addition, some or all of the functions of each layer can be included in other layers.

[0086] It should be noted that the IP layer and the layers above the IP layer, such as the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and application layer, etc. are the upper layers of the PDCP layer (not shown). In addition, the RRC layer and NAS (non-Access Stratum) layer are also the upper layers of the PDCP layer (not shown). In other words, the PDCP layer is the lower layer of the RRC layer, NAS layer, IP layer, and the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and application layer above the IP layer.

[0087] Figure 3 It is a protocol stack diagram of the UP and CP of the terminal device and the base station device in the NR radio access layer of each embodiment of the present invention.

[0088] Figure 3 Figure (A) is a protocol stack diagram of the UP used when the UE 122 communicates with the gNB 108 in NR 106.

[0089] PHY (Physical layer) 300 is the radio physical layer of NR, which can provide a transmission service to the upper layer using a physical channel. PHY 300 can be connected to the upper MAC (Medium Access Control layer) 302 described later through a transport channel. Data can move between MAC 302 and PHY 300 via the transport channel. Data can be transmitted and received between the PHYs of the UE 122 and the gNB 108 via the radio physical channel.

[0090] Here, the physical channel will be described.

[0091] The following physical channels can be used in the wireless communication between the terminal device and the base station device.

[0092] PBCH (Physical Broadcast Channel)

[0093] PDCCH (Physical Downlink Control Channel)

[0094] PDSCH (Physical Downlink Shared Channel)

[0095] PUCCH (Physical Uplink Control Channel)

[0096] PUSCH (Physical Uplink Shared Channel)

[0097] PRACH (Physical Random Access Channel)

[0098] The PBCH is used to broadcast the system information required by the terminal device.

[0099] In addition, in NR, the PBCH can be used to broadcast the time index (SSB-Index) within the period of the block of synchronization signals (also referred to as the SS / PBCH block).

[0100] The PDCCH is used to transmit (or carry) downlink control information (DCI) in the downlink wireless communication (from the base station device 3 to the terminal device). Here, one or more DCIs (which can also be referred to as DCI formats) are defined for the transmission of the downlink control information. That is, the fields for the downlink control information are defined as DCIs and are mapped to information bits. The PDCCH is transmitted in PDCCH candidates. The terminal device monitors the set of PDCCH candidates in the serving cell. Monitoring means attempting to decode the PDCCH according to a certain DCI format. A certain DCI format can be used for the scheduling of the PUSCH in the serving cell. The PUSCH can be used for the transmission of user data, the transmission of RRC messages, etc.

[0101] The PUCCH can be used to transmit uplink control information (UCI) in the wireless communication on the uplink (wireless communication from a terminal device to a base station device). Here, the uplink control information may include channel state information (CSI) for indicating the state of a downlink channel. In addition, the uplink control information may include a scheduling request (SR) for requesting UL-SCH resources. In addition, the uplink control information may include HARQ-ACK (Hybrid Automatic Repeat request ACKnowledgement).

[0102] The PDSCH can be used to transmit downlink data from the MAC layer (DL-SCH: Downlink Shared Channel). In addition, in the case of the downlink, it is also used to transmit system information (SI), random access response (RAR), etc.

[0103] The PUSCH can be used to transmit HARQ-ACK and / or CSI together with uplink data from the MAC layer (UL-SCH: Uplink Shared Channel) or uplink data. In addition, it can also be used to transmit only CSI or only HARQ-ACK and CSI. That is, it can also be used to transmit only UCI. In addition, the PDSCH or PUSCH can be used to transmit RRC signaling (also called RRC messages) and MAC control elements. Here, in the PDSCH, the RRC signaling sent from the base station device can be signaling shared by multiple terminal devices in the cell. In addition, the RRC signaling sent from the base station device can also be signaling dedicated to a certain terminal device (also called dedicated signaling). That is, dedicated signaling can be used to send UE-specific information to a certain terminal device. In addition, the PUSCH can be used to transmit the UE's capability on the uplink.

[0104] The PRACH can be used to send random access preambles. The PRACH can be used to indicate the initial connection establishment process, handover procedure, connection re-establishment process, synchronization for uplink transmission (timing adjustment), and requests for PUSCH (UL-SCH) resources.

[0105] The MAC 302 is the Medium Access Control layer that maps multiple logical channels to multiple transport channels. The MAC 302 can be connected to the upper-layer RLC (Radio Link Control layer) 304 described later through the logical channel. The logical channels can be roughly classified according to the type of information transmitted, and are divided into control channels for transmitting control information and traffic channels for transmitting user information. The MAC 302 can have functions such as controlling the PHY 300 for intermittent transmission and reception (DRX / DTX), performing the random access process, notifying information about transmission power, and performing HARQ control (Non-Patent Document 13).

[0106] The RLC 304 is the Radio Link Control layer that segments the data received from the upper-layer PDCP (Packet Data Convergence Protocol Layer) 306 described later, adjusts the data size so that the lower layer can properly transmit the data. In addition, the RLC 304 can also have a function for guaranteeing the QoS (Quality of Service) requested by each data. That is, the RLC 304 can have functions such as retransmission control of data (Non-Patent Document 12).

[0107] The PDCP 306 is the Packet Data Convergence Protocol layer for efficiently transmitting user data such as IP packets (IP Packets) in the radio section. The PDCP 306 can have a header compression function for compressing unnecessary control information. In addition, the PDCP 306 can also have functions such as data encryption and data integrity protection (Non-Patent Document 11).

[0108] The SDAP (Service Data Adaptation Protocol) 310 is a Service Data Adaptation Protocol layer with the following functions: establishing the correspondence (mapping) between the QoS flow and the DRB of the downlink sent from the 5GC 110 to the terminal device via the base station device, and mapping the QoS flow and the DRB of the uplink sent from the terminal device to the 5GC 110 via the base station device, and storing the mapping rule information (Non-Patent Document 16).

[0109] It should be noted that the data processed in the MAC 302, RLC 304, PDCP 306, and SDAP 310 are respectively called MAC PDU (Protocol Data Unit), RLC PDU, PDCP PDU, and SDAP PDU. In addition, the data transferred from the upper layer to the MAC 302, RLC 304, PDCP 306, and SDAP 310 or the data transferred to the upper layer are respectively called MAC SDU (Service Data Unit), RLC SDU, PDCP SDU, and SDAP SDU.

[0110] In addition, for the purpose of distinguishing between data use and control use, the SDAP PDU can also be respectively called SDAP DATA PDU (SDAP data PDU) and SDAP CONTROL PDU (SDAP control PDU). In addition, for the purpose of distinguishing between data use and control use, the PDCP PDU can also be respectively called PDCP DATA PDU (PDCP data PDU) and PDCP CONTROL PDU (PDCP control PDU). In addition, for the purpose of distinguishing between data use and control use, the RLC PDU can also be respectively called RLC DATA PDU (RLC data PDU) and RLCCONTROL PDU (RLC control PDU).

[0111] Figure 3 Figure (B) is a protocol stack diagram of the CP used when the UE 122 communicates with the gNB 108 and the AMF (Access and Mobility Management function), which is a logical node providing functions such as authentication and mobility management, in the NR 106.

[0112] In the protocol stack of CP, in addition to PHY300, MAC302, RLC304, and PDCP306, there are also RRC (Radio Resource Control layer) 308 and NAS (non-Access Stratum) 312. RRC308 is a radio link control layer that, in addition to performing processes such as the establishment, re-establishment, suspension, and resume of RRC connections, reconfiguration of RRC connections, for example, the establishment, change, and release of radio bearers (RBs) and cell groups, and control of logical channels, transport channels, and physical channels, also performs settings for handover and measurement. RBs can be divided into signaling radio bearers (SRBs) and data radio bearers (DRBs). SRBs can be used as paths for transmitting RRC messages as control information. DRBs can be used as paths for transmitting user data. The settings of each RB can be performed between the RRC308 of gNB108 and UE122. In addition, the part of the RB composed of RLC304 and the logical channel can also be called an RLC bearer (Non-Patent Document 10). In addition, with respect to the NAS layer that transports signals between the AMF and UE122, some or all of the layers of PHY300, MAC302, RLC304, PDCP306, RRC308, and SDAP310 that transport signals and data between UE122 and gNB108 can be called the AS (Access Stratum) layer.

[0113] In addition, SRBs can be defined as SRB0 to SRB3 as follows. SRB0 can be an SRB for RRC messages using the CCCH (Common Control Channel) of logical channels. SRB1 can be an SRB for RRC messages (possibly including piggybacked NAS messages) and NAS messages before the establishment of SRB2, and can also all use the DCCH (Dedicated Control CHannel) of logical channels. SRB2 can be an SRB for NAS messages and can also all use the DCCH of logical channels. In addition, SRB2 can have a lower priority than SRB1. SRB3 can be an SRB for specific RRC messages when the UE 122 is configured with EN-DC, NGEN-DC, NR-DC, etc., and can also all use the DCCH of logical channels. In addition, other SRBs can also be prepared for other purposes.

[0114] The functional classification of the above-mentioned MAC 302, RLC 304, PDCP 306, SDAP 310, and RRC 308 is an example, and part or all of each function may not be implemented. In addition, part or all of the functions of each layer can also be included in other layers.

[0115] It should be noted that, as described in Non-Patent Document 2, the upper layer (not shown) of the AS layer can also be referred to as the PDU layer. The PDU layer can include the IP layer and any one or all of the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and other layers above the IP layer. The application layer can be the upper layer of the PDU layer or can be included in the PDU layer. It should be noted that the PDU layer can be the upper layer of the AS layer for the user plane. In addition, the RRC layer and the NAS (non-Access Strarum) layer can also be the upper layer (not shown) of any one or all of the SDAP layer and the PDCP layer. In other words, any one or all of the SDAP layer and the PDCP layer are the lower layer of any one or all of the RRC layer, the NAS layer, the IP layer, and the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and application layer above the IP layer.

[0116] It should be noted that in each embodiment of the present invention, any one or all of SIP (Session Initiation Protocol), SDP (Session Description Protocol), etc. used in IMS, as well as RTP (Real-time Transport Protocol), RTCP (Real-time Transport Control Protocol), HTTP (HyperText Transfer Protocol), etc. for media communication or media communication control, and codecs for various media can belong to the application layer.

[0117] It should be noted that the physical layer, MAC layer, RLC layer, PDCP layer, and SDAP layer of the terminal device can be established, configured, and / or controlled in any one or all of them by the RRC layer of the terminal device. In addition, the RRC layer of the terminal device can establish and / or configure the physical layer, MAC layer, RLC layer, PDCP layer, and SDAP layer according to the RRC message sent from the RRC layer of the base station device. In addition, the MAC layer (MAC layer), RLC layer (RLC layer), PDCP layer (PDCP layer), and SDAP layer (SDAP layer) can also be referred to as the MAC sublayer (MAC sublayer), RLC sublayer (RLC sublayer), PDCP sublayer (PDCP sublayer), and SDAP sublayer (SDAP sublayer), respectively.

[0118] It should be noted that each layer or the functions of each layer belonging to the AS layer set in any one or all of the terminal device and the base station device can also be referred to as an entity. That is, the physical layer (PHY layer), MAC layer, RLC layer, PDCP layer, SDAP layer, and RRC layer or the functions of each layer that are established, configured, and controlled in any one or all of the terminal device and the base station device can be referred to as a physical entity (PHY entity), MAC entity, RLC entity, PDCP entity, SDAP entity, and RRC entity, respectively. In addition, each layer can include one or more entities of each layer. In addition, the PDCP entity and the RLC entity can be established, configured, and controlled in any one or all of them for each radio bearer. In addition, the MAC entity can be established, configured, and controlled in any one or all of them for each cell group. In addition, the SDAP entity can be established, configured, and controlled in any one or all of them for each PDU session.

[0119] Note that in the PDCP layer or PDCP entity, when performing encryption or integrity protection processing, the COUNT value can be used. The COUNT value can be composed of the HFN (Hyper Frame Number) and the sequence number (SN: Sequence Number) attached to the header of the PDCP PDU. The sequence number can be incremented by 1 each time a PDCP DATA PDU is generated in the PDCP layer or PDCP entity on the transmitting side. The HFN can be incremented by 1 each time the sequence number reaches the maximum value.

[0120] Note that in the embodiments of the present invention, in order to distinguish between the protocols of E-UTRA and NR hereinafter, MAC202, RLC204, PDCP206, and RRC208 are also respectively referred to as E-UTRA MAC or LTE MAC, E-UTRA RLC or LTE RLC, E-UTRA PDCP or LTE PDCP, and E-UTRA RRC or LTE RRC. In addition, MAC302, RLC304, PDCP306, and RRC308 are respectively referred to as NR MAC, NR RLC, NR RLC, and NR RRC. Alternatively, like E-UTRAPDCP or LTE PDCP, NR PDCP, etc. are sometimes described with spaces.

[0121] In addition, as Figure 1 shown, eNB102, gNB108, EPC104, and 5GC110 can be connected via interface 112, interface 116, interface 118, interface 120, and interface 114. Therefore, in order to correspond to multiple communication systems, Figure 2 RRC208 can be replaced with Figure 3 RRC308. In addition, Figure 2 PDCP206 can also be replaced with Figure 3 PDCP306. In addition, Figure 3 RRC308 can include Figure 2 the functions of RRC208. In addition, Figure 3 PDCP306 can be Figure 2 PDCP206. In addition, in E-UTRA100, even when the UE122 communicates with the eNB 102, NR PDCP can be used as PDCP.

[0122] Next, the state transitions of UE 122 in LTE and NR are described. A UE 122 connected to the EPC can be in the RRC_CONNECTED state when an RRC connection has been established. In addition, the UE 122 can be in the RRC_INACTIVE state when the RRC connection is aborted (if the UE 122 is connected to the 5GC). If neither of these cases holds, the UE 122 can be in the RRC_IDLE state.

[0123] It should be noted that a UE 122 connected to the EPC does not have the RRC_INACTIVE state, but can initiate the abortion of the RRC connection via the E-UTRAN. In this case, when the RRC connection is aborted, the UE 122 retains the UE's AS context and the resumeIdentity for recovery and transitions to the RRC_IDLE state. When the UE 122 retains the UE's AS context, the E-UTRAN permits the recovery of the RRC connection, and the UE 122 needs to transition from the RRC_IDLE state to the RRC_CONNECTED state, the recovery of the aborted RRC connection can be initiated by the upper layer (e.g., the NAS layer).

[0124] That is, the definition of abortion can be different for a UE 122 connected to the EPC and a UE 122 connected to the 5GC. In addition, in the case where the UE 122 is connected to the EPC (the case of abortion in the RRC_IDLE state) and the case where it is connected to the 5GC (the case of abortion in the RRC_INACTIVE state), all or part of the process of recovery from abortion can be different.

[0125] It should be noted that the RRC_CONNECTED state, the RRC_INACTIVE state, and the RRC_IDLE state can be referred to as the connected mode, the inactive mode, and the idle mode, respectively.

[0126] The AS context of the UE maintained by the UE 122 may include all or part of the information such as the current RRC configuration, the current security context, the PDCP state including the ROHC (RObust Header Compression) state, the C-RNTI (Cell Radio Network Temporary Identifier) used in the PCell of the connection source, the cell identity, and the physical cell identifier of the PCell of the connection source. It should be noted that the AS context of the UE maintained by any one or all of the eNB 102 and the gNB 108 may include the same information as the AS context of the UE maintained by the UE 122, or may include information different from the information included in the AS context of the UE maintained by the UE 122.

[0127] The security context may refer to all or part of the information including the encryption key at the AS level, the NH (Next Hop parameter), the NCC (Next Hop Chaining Counter parameter) for access key derivation for the next hop, the identifier of the selected AS-level encryption algorithm, and the counter for replay protection.

[0128] Figure 4 It is a diagram showing an example of the flow of procedures for various configurations in the RRC 208 and / or (and / or) RRC 308 representing each embodiment of the present invention. Figure 4 It is an example of the flow when an RRC message is sent from the base station device (eNB 102 and / or gNB 108) to the terminal device (UE 122).

[0129] In Figure 4Among them, the base station device generates an RRC message (step S400). The generation of the RRC message in the base station device can be performed when the base station device distributes broadcast information (SI: System Information) or paging information, or when it is determined that the base station device needs to process a specific terminal device, such as security-related settings, reconfiguration of the RRC connection (processing of radio bearers (establishment, change, release, etc.), processing of cell groups (establishment, addition, change, release, etc.), measurement settings, handover settings, etc.), release of the RRC connection state, etc. In addition, the RRC message can be used for a handover command to a different RAT. The RRC message includes information (parameters) for various information notifications and settings. In specifications related to RRC such as Non-Patent Document 4 or Non-Patent Document 10, these parameters can also be referred to as fields and / or information elements and are described using the ASN.1 (Abstract Syntax Notation One) notation.

[0130] In Figure 4 Among them, then, the base station device sends the generated RRC message to the terminal device (step S402). Then, the terminal device performs processing (step S404) in the case where processing such as setting is required according to the received RRC message.

[0131] It should be noted that the generation of the RRC message is not limited to the above examples, and as described in Non-Patent Document 4, Non-Patent Document 10, etc., it can also be generated for other purposes.

[0132] For example, the RRC message can be used for settings related to dual connectivity (DC) and multi-radio dual connectivity (MR-DC) described in Non-Patent Document 8.

[0133] Dual Connectivity (DC) can be the following technology: data communication is performed using the radio resources of both a cell group constituted by two base station apparatuses (nodes), namely, a Master Cell Group (MCG) constituted by a Master Node (MN) and a Secondary Cell Group (SCG) constituted by a Secondary Node (SN). In addition, the master node and the secondary node can be the same node (the same base station apparatus). In addition, MR-DC described in Non-Patent Document 8 can be the following technology: cells of both RATs (Radio Access Technologies) of E-UTRA and NR are grouped by each RAT and assigned to a UE, and data communication is performed using the radio resources of both the MCG and the SCG. In MR-DC, the master node can be a base station having the main RRC functions of MR-DC, such as addition of a secondary node, establishment, change, and release of RBs, addition, change, release, and handover of the MCG, etc., and the secondary node can be a base station having a part of the RRC functions, such as change and release of the SCG, etc.

[0134] In MR-DC described in Non-Patent Document 8, the RRC of the RAT on the master node side can be used to perform the settings of both the MCG and the SCG. For example, in EN-DC (E-UTRA-NR Dual Connectivity: E-UTRA-NR dual connection) of MR-DC where the core network is EPC104 and the master node is eNB102 (also referred to as extended eNB102), and in NGEN-DC (NG-RAN E-UTRA-NR Dual Connectivity: NG-RAN E-UTRA-NR dual connection) of MR-DC where the core network is 5GC110 and the master node is eNB102, the RRC message of E-UTRA described in Non-Patent Document 4 can be transmitted and received between eNB102 and UE122. In this case, the RRC message can include not only the setting information of LTE (E-UTRA) but also the setting information of NR described in Non-Patent Document 10. In addition, the RRC message sent from eNB102 to UE122 can also be sent from eNB102 to UE122 via gNB108. In addition, the configuration of this RRC message can also be used for non-MR-DC, that is, E-UTRA / 5GC where eNB102 (extended eNB) uses 5GC as the core network (Option 5 described in Non-Patent Document 17).

[0135] Furthermore, on the contrary, in MR-DC described in non-patent document 8, in NE-DC (NR-E-UTRA Dual Connectivity) of MR-DC in which the core network is 5GC110 and the master node is gNB108, the RRC message of NR described in non-patent document 10 can be sent and received between gNB108 and UE122. In this case, the RRC message can include not only the setting information of NR, but also the setting information of LTE (E-UTRA) described in non-patent document 4. In addition, the RRC message sent from gNB108 to UE122 can also be sent from gNB108 to UE122 via eNB102.

[0136] It should be noted that, not limited to the case of using MR-DC, the RRC message for E-UTRA sent from eNB102 to UE122 may include the RRC message for NR, and the RRC message for NR sent from gNB108 to UE122 may include the RRC message for E-UTRA.

[0137] In addition, the network configuration in which the master node is eNB102 and EPC104 is used as the core network may be referred to as E-UTRA / EPC. In addition, the network configuration in which the master node is eNB102 and 5GC110 is used as the core network may be referred to as E-UTRA / 5GC. In addition, the network configuration in which the master node is gNB108 and 5GC110 is used as the core network may be referred to as NR or NR / 5GC. In addition, this name may not be limited to the case where DC is set. When DC is not set, the above-mentioned master node may refer to a base station device that communicates with a terminal device.

[0138] Figure 14 It means in Figure 4 An example of an ASN.1 description of any or all of the fields and information elements related to radio bearer setup included in a message related to re-configuration of an RRC connection in NR. In addition, Figure 15 It means in Figure 4 An example of an ASN.1 description of any or all of the fields and information elements related to radio bearer setup included in a message related to re-setting of an RRC connection in E-UTRA. Figure 14 , Figure 15, in the example of ASN.1 of the embodiment of the present invention, <omitted> and <omitted> indicate that other information is omitted, rather than omitting a part of the ASN.1 expression. It should be noted that information elements can also be omitted where there is no such record as <omitted> or <omitted>. It should be noted that in the embodiment of the present invention, the example of ASN.1 does not correctly follow the ASN.1 expression method, but represents an example of the parameters of the message related to the reconfiguration of the RRC connection in the embodiment of the present invention, and other names and other expressions can also be used. In addition, to avoid the description becoming complicated, the example of ASN.1 only represents an example of the main information closely related to one aspect of the present invention. It should be noted that sometimes the parameters described by ASN.1 are not distinguished from fields, information elements, etc., but are all referred to as information elements. In addition, in the embodiment of the present invention, sometimes the fields, information elements, etc. parameters described by ASN.1 included in the RRC message are also referred to as information. It should be noted that the message related to the reconfiguration of the RRC connection can be the RRC reconfiguration message in NR or the RRC connection reconfiguration message in E-UTRA.

[0139] In Figure 14 , the information element represented by RadioBearerConfig is an information element related to the configuration of radio bearers such as SRB and DRB, and includes the PDCP configuration information element and the SDAP configuration information element described later. The information element represented by SRB-ToAddMod included in the information element represented by RadioBearerConfig can be the information representing the SRB (signaling radio bearer) configuration, and is sometimes also renamed as the SRB configuration information element or the signaling radio bearer configuration information element. In addition, the information element represented by SRB-ToAddModList can be a list of the information representing the SRB configuration. The information element represented by DRB-ToAddMod included in the information element represented by RadioBearerConfig can be the information representing the DRB (data radio bearer) configuration, and is sometimes also renamed as the DRB configuration information element or the data radio bearer configuration information element. The information element represented by DRB-ToAddModList can be a list of the information representing the DRB configuration. It should be noted that sometimes any one or all of the SRB configuration and the DRB configuration are also renamed as the radio bearer configuration.

[0140] The information element represented by SRB-Identity in the SRB configuration information element is the SRB identifier (SRB Identity) of the SRB to be added or modified, and can also be an identifier that uniquely identifies the SRB in each terminal device. Sometimes it is also referred to as the SRB identifier information element, or the radio bearer identifier information element, or the signaling radio bearer identifier information element.

[0141] The information element represented by DRB-Identity in the DRB configuration information element is the DRB identifier (DRB Identity) of the DRB to be added or modified, and can also be an identifier that uniquely identifies the DRB in each terminal device. Sometimes it is also referred to as the DRB identifier information element, or the radio bearer identifier information element, or the data radio bearer identifier information element. The value of the DRB identifier is set to an integer value from 1 to 32 in the example of Figure 14 , but other values can also be taken. In the case of DC, the DRB identifier is unique within the range of UE122.

[0142] The information element represented by cnAssociation in the DRB configuration information element can be an information element indicating whether to use EPC104 or 5GC110 in the core network, and is sometimes also referred to as the core network establishment association information element. That is, it can also be that when UE122 is connected to EPC, the DRB is associated with the EPS bearer identifier information element (eps-BearerIdentity) in cnAssociation or the EPS bearer identifier (EPS beareridentity) that is the value of the EPS bearer identifier information element, and when UE122 is connected to 5GC110, the DRB is associated with the SDAP entity set according to the SDAP configuration information element (sdap-Config) described later, or the PDU session information element described later included in the SDAP configuration information element, or the PDU session identifier that is the value of the PDU session information element, or the PDU session indicated by the PDU session information element. That is, it can also be that in the information represented by cnAssociation, in the case of using EPC104 in the core network in the case of using EN-DC, etc., the EPS bearer identifier information element (eps-BearerIdentity) is included, and in the case of using the core network 5GC110, that is, in the case of not using EN-DC, etc., the information element representing the SDAP configuration (sdap-Config) is included.

[0143] In the case where the core network is 5GC 110, the information element represented by sdap-Config may be information related to the setting or resetting of the SDAP entity for determining the correspondence (map) method between the QoS flow and the DRB, and is sometimes also referred to as the SDAP setting information element.

[0144] The field or information element represented by pdu-session or PDU-SessionID included in the SDAP setting information element may be the PDU session identifier of the PDU session described in Non-Patent Document 2 to which the QoS flow corresponding (map) to the value corresponding to the radio bearer identifier information element included in the DRB setting information element including this SDAP setting information element belongs, and is sometimes also referred to as the PDU session identifier information element. The value of the PDU session identifier information element may be a non-negative integer. In addition, in each terminal device, one PDU session identifier may correspond to multiple DRB identifiers.

[0145] The information element represented by mappedQoS-FlowsToAdd included in the SDAP setting information element may be information representing a list of QoS flow identifier (QFI: QoS Flow Identity) information elements of the QoS flow corresponding (map) or additionally corresponding (map) to the radio bearer corresponding to the value of the radio bearer identifier information element included in the DRB setting information element including this SDAP setting information element, and is sometimes also referred to as the additional QoS flow information element. The above QoS flow may be the QoS flow of the PDU session indicated by the PDU session information element included in this SDAP setting information element.

[0146] In addition, the information element represented by mappedQoS-FlowsToRelease included in the SDAP setting information element may be information representing a list of QoS flow identifier (QFI: QoS Flow Identity) information elements of the QoS flow in which the correspondence relationship is released in the QoS flow corresponding (map) to the radio bearer corresponding to the value of the radio bearer identifier information element included in the DRB setting information element including this SDAP setting information element, and is sometimes also referred to as the released QoS flow information element. The above QoS flow may be the QoS flow of the PDU session indicated by the PDU session information element included in this SDAP setting information element.

[0147] The information element represented by QFI may be a QoS flow identifier that uniquely identifies a QoS flow as described in Non-Patent Document 2, and is sometimes also referred to as a QoS flow identifier information element. The value of the QoS flow identifier information element may be a non-negative integer. In addition, the value of the QoS flow identifier information element may be unique for a PDU session.

[0148] In addition, in the SDAP configuration information element, in addition to this, it may include an uplink header information element indicating whether there is an uplink SDAP header in the uplink data transmitted via the configured DRB, a downlink header information element indicating whether there is a downlink SDAP header in the downlink data received via the configured DRB, a default bearer information element indicating whether the configured DRB is a default radio bearer (default DRB), etc.

[0149] In addition, the information element represented by pdcp-Config or PDCP-Config in the SRB configuration information element and the DRB configuration information element may be an information element related to the configuration of the NRPDCP entity for establishing and changing PDCP 306 for the SRB and / or for the DRB, and is sometimes also referred to as a PDCP configuration information element. The information element related to the configuration of the NRPDCP entity may include an information element indicating the size of the uplink sequence number, an information element indicating the size of the downlink sequence number, an information element indicating the profile of header compression (RoHC: Robust Header Compression), a re-ordering timer information element, etc.

[0150] The information element represented by DRB-ToReleaseList included in the information element represented by RadioBearerConfig may include information indicating one or more DRB identifiers to be released.

[0151] In Figure 15Among them, the information element represented by RadioResourceConfigDedicated can be an information element for the setting, change, release, etc. of a radio bearer. The information element represented by SRB-ToAddMod included in the information element represented by RadioResourceConfigDedicated can be information representing the setting of an SRB (Signaling Radio Bearer), and is sometimes also referred to as the SRB setting information element or the signaling radio bearer setting information element. The information element represented by SRB-ToAddModList can be a list of information representing the setting of an SRB. The information element represented by DRB-ToAddMod included in the information element represented by RadioResourceConfigDedicated can be information representing the setting of a DRB (Data Radio Bearer), and is sometimes also referred to as the DRB setting information element or the data radio bearer setting information element. The information element represented by DRB-ToAddModList can be a list of information representing the setting of a DRB. It should be noted that sometimes any one or all of the SRB setting and the DRB setting are also referred to as the radio bearer setting.

[0152] The information element represented by SRB-Identity in the SRB setting information element is information on the SRB identifier (SRB Identity) of the SRB to be added or changed, and can also be an identifier that uniquely identifies the SRB in each terminal device. Sometimes it is also referred to as the SRB identifier information element or the radio bearer identifier information element or the signaling radio bearer identifier information element. Figure 15 The information element represented by SRB-Identity can be an information element having the same function as Figure 14 the information element represented by SRB-Identity.

[0153] The information element represented by DRB-Identity in the DRB setting is information on the DRB identifier (DRB Identity) of the DRB to be added or changed, and can also be an identifier that uniquely identifies the DRB in each terminal device. Sometimes it is also referred to as the DRB identifier information element or the radio bearer identifier information element or the data radio bearer identifier information element. The value of the DRB identifier is set to an integer value from 1 to 32 in Figure 15 the example, but other values can also be taken. Figure 15 The information element represented by DRB-Identity can be an information element having the same function as Figure 14 the information element represented by DRB-Identity.

[0154] The information element represented by eps-BearerIdentity in the DRB setting information element may be an EPS bearer identifier that uniquely identifies an EPS bearer in each terminal device. The information element represented by eps-BearerIdentity is sometimes also referred to as the EPS bearer identifier information element. The value of the EPS bearer identifier is set to an integer value from 1 to 15 in the example of Figure 15 , but other values may also be taken. Figure 15 The information element represented by eps-BearerIdentity in Figure 14 may be an information element having the same function as the information element represented by eps-BearerIdentity in

[0155] . In addition, the EPS bearer identifier and the DRB identifier may correspond one-to-one in each terminal device.

[0156] In addition, Figure 14 or Figure 15 Some or all of the information elements shown may be optional. That is, Figure 14 or Figure 15 The information elements shown may be included in the message related to the reconfiguration of the RRC connection as needed and according to conditions. In addition, in the message related to the reconfiguration of the RRC connection, in addition to the information elements related to the setting of the radio bearer, information elements indicating the application of all settings may also be included. The information element indicating the application of all settings may be represented by an information element name such as fullConfig, or true (true) and enable (effective) etc. may also be used to indicate the application of all settings.

[0157] The information element represented by DRB-ToReleaseList included in the information element represented by RadioResourceConfigDedicated may include information indicating one or more DRB identifiers to be released.

[0158] In the following description, the eNB 102 and / or the gNB 108 are also simply referred to as the base station device, and the UE 122 is simply referred to as the terminal device.

[0159] When establishing an RRC connection, re - establishing an RRC connection, or performing handover, one serving cell provides NAS mobility information. When re - establishing an RRC connection or performing handover, one serving cell provides security inputs. This serving cell is referred to as the primary cell (PCell). In addition, depending on the capabilities of the terminal device, one or more serving cells (secondary cells, SCell) can be added and configured together with the primary cell.

[0160] In addition, a set of serving cells consisting of two subsets can be configured for the terminal device. The two subsets can be composed of: a cell group (primary cell group) consisting of one or more serving cells including the primary cell (PCell) and one or more cell groups (secondary cell groups) consisting of one or more serving cells including the primary secondary cell (PSCell) and not including the primary cell. The primary secondary cell can be the cell where the PUCCH resource is configured.

[0161] An example of the actions related to radio link failure (RLF: Radio Link Failure) of a terminal device based on an RRC connection will be described.

[0162] The terminal device obtains the following information from the base station device within the service area through broadcast information and RRC messages for each user: the values (t310, t313) of timers (such as T310, T313) for detecting physical layer problems of the serving cell, N310, N313 which are the thresholds for the number of out - of - sync (OoS) detections, N311, N314 which are the thresholds for the number of in - sync (IS) detections, etc. In addition, default values can be set for the values of the timers and the thresholds of the number of times. In addition, the names of the timers can be different in EUTRA and NR.

[0163] For wireless link monitoring, when the physical layer processing unit of the terminal device estimates (for example, based on information such as the received power of the received reference signal and / or the received power of the synchronization signal and / or the packet error rate) that the radio link quality of the serving cell is worse than a specific threshold (Qout) for more than a specific period (for example, TEvaluate_Qout = 200 ms), it notifies the RRC layer processing unit, which is the upper layer, of "out-of-sync". In addition, when the physical layer processing unit estimates (for example, based on information such as the received power of the received reference signal and / or the received power of the synchronization signal and / or the packet error rate) that the radio link quality of the serving cell exceeds a specific threshold (Qin) for more than a specific period (for example, TEvaluate_Qin = 100 ms), it notifies the RRC layer processing unit, which is the upper layer, of "in-sync". It should be noted that the physical layer processing unit can notify the upper layer of out-of-sync or in-sync at intervals of more than a specific interval (for example, TReport_sync = 10 ms).

[0164] Here, for example, the threshold Qout can be defined as the following level: the radio link of the downlink cannot be received reliably, and the block error rate of the transmission of the hypothetical downlink control channel (PDCCH) based on the established parameters is a first specific ratio. In addition, for example, the threshold Qin can also be defined as the following level: the radio link quality of the downlink can be received significantly and more reliably than the state of Qout, and the block error rate of the transmission of the hypothetical downlink control channel based on the established parameters is a second specific ratio. In addition, multiple block error rates (the levels of the threshold Qout and the threshold Qin) can be defined based on the frequency used, the subcarrier spacing, the type of service, etc. In addition, the first specific ratio and / or the second specific ratio can be established values specified in the specification. In addition, the first specific ratio and / or the second specific ratio can also be values notified or broadcast by the base station device to the terminal device.

[0165] The terminal device can use a certain type of reference signal (e.g., cell-specific reference signal (CRS)) in the serving cell (e.g., PCell and / or PSCell) for radio link monitoring. In addition, the terminal device can receive from the base station device a setting (radio link monitoring setting: RadioLinkMonitoringConfig) indicating which reference signal to use in radio link monitoring in the serving cell (e.g., PCell and / or PSCell), and use the set one or more reference signals (hereinafter referred to as RLM-RS) for radio link monitoring. In addition, the terminal device can also use other signals for radio link monitoring. The physical layer processing unit of the terminal device can notify the upper layer of being in synchronization when the conditions for being in synchronization are met in the serving cell (e.g., PCell and / or PSCell).

[0166] The radio link monitoring setting may include information indicating the purpose of monitoring and information indicating the identifier of the reference signal. For example, the purpose of monitoring may include the purpose of monitoring radio link failure, the purpose of monitoring beam failure, or both purposes. In addition, for example, the information indicating the identifier of the reference signal may include information indicating the identifier (SSB-Index) of the synchronization signal block (SSB) of the cell. That is, the reference signal may include a synchronization signal. In addition, for example, the information indicating the identifier of the reference signal may include information indicating the identifier associated with the channel state information reference signal (CSI-RS) set for the terminal device.

[0167] In the primary cell, the RRC layer processing unit of the terminal device can start (Start) or restart (Restart) the timer (T310) when it receives notifications of out-of-synchronization from the physical layer processing unit continuously for a predetermined number of times (N310 times). In addition, the RRC layer processing unit of the terminal device can stop (Stop) the timer (T310) when it receives notifications of being in synchronization continuously for a predetermined number of times (N311 times). The RRC layer processing unit of the terminal device can be made to perform a transition to the idle state or a RRC connection re-establishment process when the timer (T310) expires (Expire). For example, the operation of the terminal device may vary depending on the establishment state of AS security (AS Security). When AS security is not established, the terminal device can transition to the RRC IDLE state, and when AS security is established, the terminal device can perform a RRC connection re-establishment process. In addition, in the determination of starting or restarting the timer T310, it can be added to the conditions that the timers T300, T301, T304, and T311 are not running.

[0168] In Figure 9 An example of the start, stop, and expiration conditions of the respective timers of EUTRA is shown. It should be noted that in NR, sometimes the timer name and / or message name may also be different, but the same conditions can also be applied.

[0169] In addition, in the primary and secondary cells, the RRC layer processing unit of the terminal device can start (Start) or restart (Restart) the timer (T313) when it receives notifications from the physical layer processing unit that are out of synchronization for a continuous predetermined number of times (N313 times). In addition, the RRC layer processing unit of the terminal device can stop (Stop) the timer (T313) when it receives synchronization for a continuous predetermined number of times (N314 times). The RRC layer processing unit of the terminal device can execute the SCG failure information procedure for notifying the network of an SCG failure when the timer (T313) expires (Expire).

[0170] In addition, in the SpCell (PCell in MCG and PSCell in SCG), the RRC layer processing unit of the terminal device can start (Start) or restart (Restart) the timer (T310) of that SpCell when it receives notifications from the physical layer processing unit that are out of synchronization for a continuous predetermined number of times (N310 times) in each SpCell. In addition, the RRC layer processing unit of the terminal device can stop (Stop) the timer (T310) of that SpCell when it receives synchronization for a continuous predetermined number of times (N311 times) in each SpCell. When the timer (T310) of each SpCell expires (Expire), if the SpCell is a PCell, the RRC layer processing unit of the terminal device can be made to perform a transition to the idle state or a procedure for re-establishing the RRC connection. In addition, if the SpCell is a PSCell, the SCG failure information procedure for notifying the network of an SCG failure can be executed.

[0171] The above description is an example in the case where discontinuous reception (DRX) is not set for the terminal device. In the case where DRX is set for the terminal device, the RRC layer processing unit of the terminal device can set the time period for measuring the radio link quality and the notification interval to the upper layer for the physical layer processing unit, so that they take values different from those in the case where DRX is not set. It should be noted that even in the case where DRX is set, when the above timers (T310, T313) are running, the time period for measuring the radio link quality used for estimating synchronization and the notification interval to the upper layer can be set to the values in the case where DRX is not set.

[0172] In addition, for example, in order to detect early physical layer problems, the RRC layer processing unit of the terminal device can start (Start) the timer (T314) when it receives notifications from the physical layer processing unit that are outside of early synchronization for a continuous predetermined number of times (N310 times). In addition, the RRC layer processing unit of the terminal device can stop (Stop) the timer (T314) when it receives notifications of being in synchronization for a continuous predetermined number of times (N311 times) while T314 is running.

[0173] In addition, for example, in order to detect early physical layer improvement, the RRC layer processing unit of the terminal device can start (Start) the timer (T315) when it receives notifications of being in early synchronization from the physical layer processing unit for a continuous predetermined number of times (N311 times). In addition, the RRC layer processing unit of the terminal device can stop (Stop) the timer (T315) when it receives notifications of being in synchronization for a continuous predetermined number of times (N311 times) while T315 is running.

[0174] In addition, for example, when reporting the measurement to the base station device, in the case where the setting of the measurement is set to perform a first measurement (for example, a measurement using timer T312), if timer T310 is running and timer T312 is not running, then start timer T312. The RRC layer processing unit of the terminal device can stop the timer (T312) when it receives notifications of being in synchronization for a continuous predetermined number of times (N311 times).

[0175] In addition, in the case where it is not explicitly or implicitly set by the network, the RLM-RS may be undefined. That is, in the case where the network (such as a base station device) does not set the RLM-RS, the terminal device may not perform radio link monitoring.

[0176] In addition, the RLM-RS is a reference signal used in radio link monitoring, and multiple RLM-RSs can be set for the terminal device. The resource of one RLM-RS can be one SS block or the resource (or port) of one CSI-RS.

[0177] In addition, wireless link monitoring using CRS can be performed in a cell of EUTRA, and wireless link monitoring using RLM-RS can be performed in a cell of NR, but it is not limited thereto.

[0178] The detection of a wireless link failure based on wireless link monitoring will be described.

[0179] When the timer T310 expires, the timer T312 expires, when multiple specific timers are not running, when the terminal device is notified of a random access problem from the MAC layer of the MCG, or when the terminal device is notified from the RLC layer of the MCG that the retransmission of the SRB or DRB has reached the maximum number of retransmissions, the terminal device determines that a wireless link failure has been detected in the MCG. The specific timers do not include the timer T310 and the timer T312.

[0180] It may be that in the MAC entity, when the number of retransmissions of the random access preamble reaches a predetermined number, if the random access preamble is transmitted in the SpCell, the MAC entity of the cell group including the SpCell notifies the upper layer (here, the RRC entity) of the random access problem.

[0181] When the terminal device determines that a wireless link failure has been detected in the MCG, it stores various information as wireless link failure information. Then, if the AS security is not activated, the release reason is set to "other" and the process of leaving RRC_CONNECTED is started. If the AS security is activated, the process of re-establishing the RRC connection is started.

[0182] When the timer T313 expires, when the terminal device is notified of a random access problem from the MAC layer of the SCG, or when the terminal device is notified from the RLC layer of the SCG that the retransmission has reached the maximum number of retransmissions, the terminal device determines that a wireless link failure has been detected in the SCG and starts the process of reporting the information associated with the SCG wireless link failure to the base station device.

[0183] When the timer T314 expires, the terminal device determines that the terminal device has detected an "out-of-early-synchronization" event and starts the process of reporting the associated information to the base station device.

[0184] When the timer T315 expires, the terminal device determines that the terminal device has detected an "in-early-synchronization" event and starts the process of reporting the associated information to the base station device.

[0185] The process of re-establishing the RRC connection will be described.

[0186] The purpose of the RRC connection re - establishment procedure is to re - establish the RRC connection, which may be accompanied by the resumption process of SRB1, the re - activation of security, and the configuration of only the PCell.

[0187] The RRC connection re - establishment procedure can be started when any one of the following conditions (A) to (E) is met.

[0188] (A) When a radio link failure of the MCG is detected

[0189] (B) When a handover fails (when the synchronization re - configuration in the MCG fails in NR)

[0190] (C) When the movement to another RAT fails

[0191] (D) When notified from the lower layer of a failure in the integrity check related to SRB1 or SRB2

[0192] (E) When the RRC connection re - configuration fails

[0193] When the RRC connection re - establishment procedure starts, the terminal device performs some or all of the following processes (A) to (J).

[0194] (A) If timer T310 is running, stop timer T310

[0195] (B) If timer T312 is running, stop timer T312

[0196] (C) If timer T313 is running, stop timer T313

[0197] (C) If timer T314 is running, stop timer T314

[0198] (D) Start timer T311

[0199] (E) Suspend all RBs other than SRB0

[0200] (F) Reset MAC

[0201] (G) If configured, release the SCell of the MCG

[0202] (H) Apply the default physical channel configuration

[0203] (I) Apply the default MAC master configuration to the MCG

[0204] (J) Execute the cell selection process

[0205] When selecting the optimal cell of the same RAT through the cell selection process, the terminal device performs the following processing.

[0206] If the terminal device is connected to the 5GC and the selected cell can only be connected in the EPC, or the terminal device is connected to the EPC and the selected cell can only be connected in the 5GC, then set the release reason to "RRC connection failure" and perform the action of leaving RRC_CONNECTED. Otherwise, stop timer T311, start timer T301, and start sending the ReestablishmentRequest message for RRC connection reestablishment.

[0207] When timer T311 expires, the terminal device sets the release reason to "RRC connection failure" and performs the action of leaving RRC_CONNECTED.

[0208] If timer T301 expires or the selected cell is no longer the optimal cell from the perspective of the cell selection criterion, then the terminal device sets the release reason to "RRC connection failure" and performs the action of leaving RRC_CONNECTED.

[0209] The handover is described.

[0210] Using Figure 7 , an example of the processing related to handover between the same RATs (i.e., between EUTRAs) in EUTRA is described. The description using Figure 7 is an example, and part of the processing can be omitted, or other processing can be included. Or other processing can be performed as the processing related to handover.

[0211] In Figure 7 , the base station device of the handover source (source eNB) configures the terminal device to measure the neighboring cell (step S701).

[0212] The terminal device performs the measurement configured by the source eNB and reports the measurement result to the source eNB based on the reporting condition (step S702).

[0213] The source eNB decides the handover of the terminal device based on the reported measurement result and other information (step S703).

[0214] The source eNB issues a handover request message including the information required for preparing the handover to the base station device as the handover destination (Target eNB: target eNB) (step S704).

[0215] Admission control can be performed in the target eNB. The target eNB sets the required resources (step S705).

[0216] The target eNB sends a handover request acknowledge message (HANDOVER REQUEST ACKNOWLEDGE message) to the source eNB (step S706). The handover request acknowledge message includes a container that is transparently sent to the terminal device as an RRC message for the execution of the handover. The container may include a new C-RNTI, a security algorithm identifier of the target eNB for the selected security algorithm, a preamble of a dedicated random access channel (random access preamble), a part or all of the system information of the target cell.

[0217] The source eNB sends the container received from the target eNB (the first RRC connection reconfiguration message (RRCConnectionReconfiguration message) including the mobility control information (mobilityControlInfo) information element (Information Element: IE)) to the terminal device (step S707).

[0218] It should be noted that when the terminal device is configured with make-before-break handover (Make-Before-Break HO: MBB-HO) through the first RRC connection reconfiguration message, after receiving the first RRC connection reconfiguration message, it maintains the connection with the source eNB at least in the target eNB until the first uplink transmission is performed. It should be noted that the above make-before-break handover can be selected from multiple configurations. For example, it can be determined that the make-before-break handover is configured when makeBeforeBreak-r14 in the fields included in the already standardized mobilityControlInfo information element is set to true (True). In addition, for example, it can be determined that the make-before-break handover is configured when the newly defined makeBeforeBreak-r16 is included in the fields of the mobilityControlInfo information element and the makeBeforeBreak-r16 is set to true (True). In addition, the field makeBeforeBreak-r16 can use an information element including various configurations as a value.

[0219] The source eNB sends an SN status transfer (SN STATUS TRANSFER) message for conveying the reception status of the PDCP sequence number of the uplink and the transmission status of the PDCP sequence number of the downlink to the target eNB (step S708).

[0220] If RACH-less handover is not configured by the first RRC connection reconfiguration message, the terminal device performs synchronization to the target eNB and accesses the target cell using the random access channel. At this time, if a dedicated random access preamble is indicated by the first RRC connection reconfiguration message, a contention-free random access procedure is performed; if no dedicated random access preamble is indicated, a contention-based random access procedure is performed. If RACH-less handover is configured by the first RRC connection reconfiguration message, the terminal device performs synchronization to the target eNB (step S709).

[0221] If RACH-less handover is not configured by the first RRC connection reconfiguration message, the target eNB returns the uplink allocation and timing advance information to the terminal device (step S710).

[0222] If RACH-less handover is configured by the first RRC connection reconfiguration message and a periodic pre-allocated uplink grant cannot be obtained from the first RRC connection reconfiguration message, the terminal device receives the uplink grant via the PDCCH of the target cell. The terminal device uses the first available uplink grant after synchronizing to the target cell (step S710a).

[0223] When RACH-less handover is not configured and the terminal device successfully accesses the target cell, the terminal device sends an RRC connection reconfiguration complete message (RRCConnectionReconfigurationComplete message) to the target eNB to confirm the handover. This RRC connection reconfiguration complete message indicates the completion of the handover process of the terminal device. The RRC connection reconfiguration complete message includes the C-RNTI, and the target eNB verifies the C-RNTI of the accepted RRC connection reconfiguration complete message.

[0224] When RACH-less handover is configured and the terminal device receives an uplink grant, the terminal device sends an RRC connection reconfiguration complete message (RRCConnectionReconfigurationComplete message) to the target eNB to confirm the handover. The RRC connection reconfiguration complete message includes the C-RNTI, and the target eNB verifies the C-RNTI of the accepted RRC connection reconfiguration complete message. When the terminal device receives a UE contention resolution identity MAC control element from the target eNB, the handover process of the terminal device is completed (step S711).

[0225] The target eNB sends a PATH SWITCH REQUEST to the MME to notify that the cell of the terminal device has changed (step S712).

[0226] The MME sends a MODIFY BEARER REQUEST message to the serving gateway (S-GW) (step S713).

[0227] The S-GW switches the downlink data path to the target side. The S-GW sends one or more end marker packets to the source eNB to release the resources of the user plane to the source eNB (step S714).

[0228] The S-GW sends a MODIFY BEARER RESPONSE message to the MME (step S715).

[0229] The MME confirms the path switch request through a PATH SWITCH REQUEST ACKNOWLEDGE message (step S716).

[0230] The target eNB indicates the success of the handover by sending a UE CONTEXT RELEASE message to the source eNB, triggering the release of resources by the source eNB. The target eNB may send this message after accepting the path switch request acknowledge message (step S717).

[0231] The source eNB can release the radio and C-plane associated resources related to the UE context when accepting the UE context release message. The ongoing data transmission can continue (step S718).

[0232] When timer T304 expires, the terminal device performs some or all of the following processes (A) to (D).

[0233] (A) Consider the setting of the dedicated random access channel set by the first RRC connection reconfiguration message as unavailable

[0234] (B) Return the settings of the terminal device to the settings of the dedicated physical channel, the main settings of the MAC layer, and the settings used in the PCell of the handover source except for the settings of semi-persistent (semi-static) scheduling

[0235] (C) Store the associated information as handover failure information

[0236] (D) Start the RRC connection re-establishment process and end the RRC connection reconfiguration process

[0237] Describe the details of the processing of the terminal device that receives the first RRC connection reconfiguration message. The first RRC connection reconfiguration message may include a mobilityControlInfo information element. The mobilityControlInfo information element includes parameters related to mobility controlled by the network from other RATs to EUTRA or within EUTRA (e.g., the identifier of the target cell, information on the carrier frequency).

[0238] If the terminal device receives an RRC connection reconfiguration message (the first RRC connection reconfiguration message) including the mobilityControlInfo information element and can satisfy the settings of the message, the terminal device performs some or all of the following processes (A) to (G).

[0239] (A) If timer T310 is running, stop timer T310

[0240] (B) If timer T312 is running, stop timer T312

[0241] (C) If timer T314 is running, stop timer T314

[0242] (D) Start timer T304 with the value (t304) included in the mobilityControlInfo information element

[0243] (E) If information on the carrier frequency is included, determine that frequency as the frequency of the target cell. If information on the carrier frequency is not included, determine the frequency of the source PCell as the frequency of the target cell

[0244] (F) If the access restriction timer is running, stop the timer.

[0245] (G) Start synchronization of the target cell to the downlink.

[0246] Use Figure 8 , to illustrate an example of the processing related to handover between the same RATs (i.e., between NRs) in NR. The description using Figure 8 is an example, and part of the processing can be omitted, or other processing can be included. Or other processing can be performed as the processing related to handover.

[0247] In Figure 8 , the base station device of the handover source (Source gNB) sets the measurement of the neighboring cell for the terminal device, and the terminal device performs the measurement set by the source gNB and reports the measurement result to the source gNB (step S801).

[0248] The source gNB decides the handover of the terminal device based on the information such as the reported measurement result (step S802).

[0249] The source gNB issues a handover request message including the information required for the preparation of the handover to the base station device (Target gNB) as the handover destination (step S803).

[0250] Admission control can be performed in the target gNB (step S804).

[0251] The target gNB prepares for the handover and sends a handover request acknowledgment message (HANDOVER REQUEST ACKNOWLEDGE message) to the source gNB (step S805). The handover request acknowledgment message includes a container that is transparently sent to the terminal device as an RRC message for the execution of the handover.

[0252] The source gNB sends the container (the first RRC reconfiguration message (RRC Reconfiguration message)) received from the target gNB to the terminal device (step S806). The RRC reconfiguration message may include the identifier of the target cell, the new C-RNTI, the security algorithm identifier of the target gNB for the selected security algorithm, the set of resources of the dedicated random access channel, the setting of the UE-specific CSI-RS, the common random access channel resources, and part or all of the system information of the target cell.

[0253] Note that when the terminal device is configured with Make-Before-Break HO (MBB-HO) by the first RRC reconfiguration message, after receiving the first RRC reconfiguration message, it maintains the connection with the source gNB in the target gNB at least until the first uplink transmission is performed.

[0254] The source eNB sends an SN status transition message for conveying the reception status of the PDCP sequence number for the uplink and the transmission status of the PDCP sequence number for the downlink to the target gNB (step S807).

[0255] If RACH-less handover is not configured by the first RRC reconfiguration message, the terminal device performs synchronization to the target eNB and accesses the target cell using the random access channel. At this time, if a dedicated random access preamble is indicated by the first RRC reconfiguration message, a contention-free random access procedure is performed; if a dedicated random access preamble is not indicated, a contention-based random access procedure is performed. If RACH-less handover is configured by the first RRC reconfiguration message, the terminal device performs synchronization to the target gNB.

[0256] If RACH-less handover is not configured by the first RRC reconfiguration message, the target gNB may return information on uplink allocation and timing advance to the terminal device.

[0257] If RACH-less handover is configured by the first RRC reconfiguration message and a periodic pre-allocated uplink grant cannot be obtained through the first RRC reconfiguration message, the terminal device receives an uplink grant through the PDCCH of the target cell. The terminal device uses the first available uplink grant after synchronizing to the target cell.

[0258] When RACH-less handover is not configured and the terminal device successfully accesses the target cell, the terminal device may send an RRC reconfiguration complete message (RRCReconfigurationComplete message) to the target gNB to confirm the handover. This RRC reconfiguration complete message may indicate the completion of the handover process of the terminal device. The RRC reconfiguration complete message includes a C-RNTI, and the target gNB may verify the C-RNTI of the accepted RRC reconfiguration complete message.

[0259] When RACH-less handover is configured and the terminal device receives an uplink grant, the terminal device may send an RRC Reconfiguration Complete message to the target gNB to confirm the handover. The RRC Reconfiguration Complete message includes a C-RNTI, and the target gNB may verify the C-RNTI of the accepted RRC Reconfiguration Complete message. It may be that when the terminal device receives a UE contention resolution identity MAC control element from the target gNB, the handover process of the terminal device is completed (step S808).

[0260] The target eNB sends a PATH SWITCH REQUEST message to the AMF to switch the downlink data path to the target gNB by the 5GC, causing the target gNB to establish an NG-C interface instance (step S809).

[0261] The 5GC switches the downlink data path to the target gNB. The UPF (User Plane Function) sends one or more end marker packets to the source eNB to release the resources of the user plane to the source gNB (step S810).

[0262] The AMF confirms the path switch request through a PATH SWITCH REQUEST ACKNOWLEDGE message (step S811).

[0263] The target gNB indicates the success of the handover by sending a UE CONTEXT RELEASE message to the source eNB, triggering the release of resources by the source gNB. The target gNB may send this message after receiving the path switch request acknowledge message from the AMF. The source gNB can release the radio and C-plane associated resources related to the UE context when accepting the UE context release message. The ongoing data transmission may continue (step S812).

[0264] When the timer T304 expires, the terminal device performs some or all of the following processes (A) to (D).

[0265] (A) If the timer T304 of the MCG expires, release the setting of the dedicated random access channel of the MCG set by the first RRC connection reconfiguration message

[0266] (B) If the timer T304 of the MCG expires, the settings of the terminal device are returned to the settings used in the PCell of the handover source.

[0267] (D) If the timer T304 of the MCG expires, the RRC connection re - establishment process is started.

[0268] (E) If the timer T304 of the SCG expires, the settings of the dedicated random access channel of the SCG set by the first RRC connection re - configuration message are released.

[0269] (E) If the timer T304 of the SCG expires, the process of reporting the failure of the SCG synchronization re - configuration is started.

[0270] The details of the processing of the terminal device that receives the first RRC re - configuration message are described. The reconfigurationWithSync information element may be included in the first RRC re - configuration message. The reconfigurationWithSync information element may be included in the settings of the SpCell of each cell group (MCG, SCG) of the RRC re - configuration message. The reconfigurationWithSync information element includes parameters related to the re - configuration accompanied by synchronization to the target SpCell (for example, the settings of the target SpCell, the new identifier of the terminal device, etc.).

[0271] The terminal device that receives the RRC re - configuration message (the first RRC re - configuration message) including the reconfigurationWithSync information element performs part or all of the following processes (A) to (E).

[0272] (A) If the security is not activated, the release reason is set to "other" and the process of leaving RRC_CONNECTED is started. The process of leaving RRC_CONNECTED may be the process of entering RRC_IDLE.

[0273] (B) If the timer T310 of the target SpCell is running, the timer T310 of the target SpCell is stopped.

[0274] (C) The timer T304 of the target SpCell is started with the value (t304) included in the reconfigurationWithSync information element.

[0275] (D) If the information on the downlink frequency is included, the frequency is determined as the frequency of the SSB of the target cell. If the information on the downlink frequency is not included, the frequency of the SSB of the source SpCell is determined as the frequency of the SSB of the target cell.

[0276] (E) Start the synchronization of the target cell to the downlink.

[0277] As described above, in EUTRA and / or NR, in the case of making a make-before-break handover (MBB-HO) for a terminal device, the terminal device can maintain the connection with the source eNB or source gNB in the target eNB or target gNB until the first uplink transmission is performed or for any period of time. Currently, when receiving the first RRC connection reconfiguration message or the first RRC reconfiguration message, the timer T310 stops. Therefore, in the serving cell (source cell) of the source eNB or source gNB hereafter, the terminal device cannot determine whether it is a situation regarded as a radio link failure caused by a physical layer problem. In addition, when the timer T304 is running, in the serving cell (source cell) of the source eNB or source gNB, the terminal device cannot determine whether it is a situation regarded as a radio link failure caused by a random access problem notified from the MAC layer. In addition, in the source cell, when the retransmission in the RLC reaches the maximum number of times, it is regarded as a radio link failure, and the RRC connection reestablishment process is executed.

[0278] It should be noted that in the make-before-break handover (MBB-HO), the protocol layers activated separately on the source side and the target side can be used to maintain the connection with the source eNB or source gNB until the first uplink transmission is performed by the target eNB or target gNB or for any period of time. Therefore, the make-before-break handover (MBB-HO) can also be renamed as the DAPS (Dual Active Protocol Stack) handover. In the DAPS handover, in the PDCP entity, two confidentiality keys and / or two integrity keys and / or two RoHC protocols for the source and the target can be set, two RLC bearers for the source and the target can also be set, and two MAC entities for the source and the target can also be set. In addition, a part or all of the confidentiality keys, integrity keys, RoHC protocols, RLC bearers, and MAC bearers set for the source and the target as described above can be used simultaneously or alternately when performing a handover using DAPS. Hereinafter, the make-before-break handover (MBB-HO) can be replaced with the DAPS handover.

[0279] In addition, hereinafter, the apply-then-break handover may also be the DAPS handover. In addition, setting the apply-then-break handover (MBB-HO) for the terminal device may be setting the DAPS handover for the terminal device. In addition, setting the apply-then-break handover (MBB-HO) (setting the DAPS handover) for the terminal device may be applying MBB-HO (DAPS handover) to any radio bearer set in the terminal device, or may be applying MBB-HO (DAPS handover) to at least one of the radio bearers set in the terminal device.

[0280] Next, conditional handover will be described. In NR, the conditional handover may be an RRC reconfiguration using an RRC reconfiguration message that includes: an information element (conditional handover setting) containing the information included in the synchronization reconfiguration information element, and information (conditional handover condition) indicating the condition for applying this information element. In LTE, the conditional handover may be an RRC connection reconfiguration using an RRC connection reconfiguration message that includes: an information element (conditional handover setting) containing the information included in the mobility control information information element, and information (conditional handover condition) indicating the condition for applying this information element.

[0281] In NR, the conditional handover setting may include a part or all of the following settings (A) to (F).

[0282] (A) Cell group configuration information (CellGroupConfig)

[0283] (B) Information indicating whether it is a full setting

[0284] (C) NAS layer message

[0285] (D) System information

[0286] (E) Measurement setting

[0287] (F) Radio bearer setting

[0288] The cell group configuration information may include a part or all of the following settings (1) to (6).

[0289] (1) Cell group identifier

[0290] (2) RLC bearer information

[0291] (3) MAC layer configuration information of the cell group

[0292] (4) Physical (PHY) layer configuration information of the cell group

[0293] (5) Setting information of SpCell (which may include a synchronization re - setting information element)

[0294] (6) Information of SCell

[0295] In addition, the setting of the radio bearer may include some or all of the following settings (1) - (3).

[0296] (1) SRB setting

[0297] (2) DRB setting

[0298] (3) Security setting (for example, information related to algorithms for integrity protection and encryption for SRB and / or DRB (securityAlgorithmConfig), information indicating which key (primary (MCG), secondary (SCG)) to use (keyToUse), etc.)

[0299] In LTE, the conditional handover setting may include some or all of the following settings (A) - (E).

[0300] (A) Measurement setting

[0301] (B) Mobility control information information element

[0302] (C) NAS layer message

[0303] (D) Radio resource setting

[0304] (E) Security setting (for example, information related to algorithms for integrity protection and encryption for SRB and / or DRB (SecurityAlgorithmConfig))

[0305] The radio resource setting may include some or all of the following settings (1) - (4).

[0306] (1) SRB information

[0307] (2) DRB information

[0308] (3) MAC layer setting information of the cell group

[0309] (4) Physical (PHY) layer setting information of the cell group

[0310] In LTE and / or NR, the conditional handover conditions may include some or all of the following conditions (A) - (D).

[0311] (A) The cell of the handover destination (target) is better than the current (source) PCell with an offset applied

[0312] (B) The target cell for handover is better than a certain threshold, and the PCell is worse than another threshold

[0313] (C) The target cell for handover is better than a certain threshold

[0314] (D) Unconditional (execute immediately)

[0315] In the comparison under the above conditional handover conditions, RSRP, RSRQ, and / or RS-SINR can be used as a quantity. In addition, it can be set from the network which quantity to use. In addition, the information indicating which quantity to use can be included in the conditional handover conditions.

[0316] The information element indicating the conditional handover setting and / or the conditional handover conditions can be included as part of the RRC message in the handover source, or can be stored in a container (information element storing a bit string) included in the RRC message.

[0317] Based on the above description, various embodiments of the present invention will be described. It should be noted that the above-described various processes can be applied to each process omitted in the following description.

[0318] An example of efficiently performing MBB-HO by changing the process related to radio link monitoring in MBB-HO is shown.

[0319] First, in the primary cell (PCell) of the SpCell as the MCG, regardless of whether the timer T304 is running under a specific condition (the first condition), the RRC layer processing unit of the UE122 can start or restart the timer (T310) when it continuously receives notifications from the physical layer processing unit that there is no synchronization for a predetermined number of times (N310 times). In addition, the RRC layer processing unit of the UE122 can stop the timer (T310) when it continuously receives synchronization for a predetermined number of times (N311 times). In addition, in the determination of starting or restarting the timer T310, it can be added to the condition that the timers T300, T301, and T311 are not running.

[0320] The RRC layer processing unit of the UE122 determines that a radio link failure is detected in the MCG when any of the following conditions (A) to (E) is satisfied.

[0321] (A) When the timer T310 expires

[0322] (B) When the timer T312 expires

[0323] (C) When the timers T300, T301, T304, and T311 are not running and a notification (indication) of a random access problem is received from the MAC entity of the MCG

[0324] (D) When the timer T304 is running under the first condition and a notification of a random access problem is received from the MAC entity of the MCG

[0325] (E) When a notification indicating that the retransmission of an SRB or DRB has reached the maximum number of retransmissions is received from the RLC layer of the MCG

[0326] The first condition may be that makeBeforeBreak-r16 is configured in the UE122. For example, in the case of EUTRA, the UE122 receiving a makeBeforeBreak-r16 included in the field of the mobilityControlInfo information element in the RRC connection reconfiguration message may be that makeBeforeBreak-r16 is configured. In addition, for example, in the case of NR, receiving a makeBeforeBreak-r16 included in the field of the synchronization reconfiguration information element in the RRC reconfiguration message may be that makeBeforeBreak-r16 is configured. In addition, for example, in the case of EUTRA, the UE122 receiving an RRC connection reconfiguration message in which makeBeforeBreak-r16 is not included in the field of the mobilityControlInfo information element may be that makeBeforeBreak-r16 is not configured. In addition, for example, in the case of EUTRA, the UE122 receiving an RRC connection reconfiguration message including a makeBeforeBreak-r16 with a false value may be that makeBeforeBreak-r16 is not configured. In addition, for example, in the case of NR, receiving an RRC reconfiguration message in which makeBeforeBreak-r16 is not included in the field of the synchronization reconfiguration information element may be that makeBeforeBreak-r16 is not configured.

[0327] In addition, for example, in the case of EUTRA, the UE122 receiving an RRC connection reconfiguration message in which makeBeforeBreak-r16 is included in the radioBearerConfigDedicated information element specific to the terminal device may be that makeBeforeBreak-r16 is configured. In addition, for example, in the case of NR, receiving an RRC reconfiguration message in which makeBeforeBreak-r16 is included in the field of the data radio bearer configuration information element may be that makeBeforeBreak-r16 is configured.

[0328] The makeBeforeBreak-r16 can have a value of an enumerated type including true, or can have an information element including the information required for the make-before-break switch as a value.

[0329] In addition, the condition (E) can be the following (E2).

[0330] (E2) When none of the timers T300, T301, T304, and T311 are running and a notification indicating that the retransmission of an SRB or DRB has reached the maximum number of retransmissions is received from the RLC layer of the MCG, or when the timer T304 is running under the first condition and a notification indicating that the retransmission of an SRB or DRB has reached the maximum number of retransmissions is received from the RLC layer of the MCG

[0331] When the UE122 determines that a radio link failure has been detected in the MCG, it stores various information as radio link failure information. Then, if the security of the AS is not activated, the release reason can be set to "other" and the process of leaving the RRC CONNECTED state can be started.

[0332] In addition, in the case where the AS security is activated, if it is under the first condition, the transmission of some or all of the SRBs and / or DRBs in the MCG can be suspended, and the MAC entity of the MCG can be reset.

[0333] In addition, in the case where the AS security is activated, if it is not under the first condition, the process of re-establishing the RRC connection is started.

[0334] The process of re-establishing the RRC connection can be started when any one of the following conditions (A) to (E) is met.

[0335] (A) When a radio link failure of the MCG is detected under non-first conditions

[0336] (B) When a handover fails (when the synchronization reconfiguration in the MCG fails in NR)

[0337] (C) When the movement to another RAT fails

[0338] (D) When notified from the lower layer of a failure in the integrity check related to SRB1 or SRB2

[0339] (E) When the reconfiguration of the RRC connection fails

[0340] In addition, when any of the above conditions is met, under the first condition and when no radio link failure is detected in the MCG of the handover source, the process of re - establishing the RRC connection may not be started, and the process of notifying handover failure in the MCG of the handover source may be started.

[0341] If the first condition is that makeBeforeBreak - r16 is set for UE122, the set makeBeforeBreak - r16 may be released when timer T304 expires or when the process of notifying handover failure in the MCG of the handover source is started.

[0342] When the process of re - establishing the RRC connection is started, UE122 performs some or all of the following processes (A) to (J).

[0343] (A) If timer T310 is running, stop timer T310

[0344] (B) If timer T312 is running, stop timer T312

[0345] (C) If timer T313 is running, stop timer T313

[0346] (C) If timer T314 is running, stop timer T314

[0347] (D) Start timer T311

[0348] (E) Suspend all RBs other than SRB0

[0349] (F) Reset MAC

[0350] (G) If set, release the SCell of the MCG

[0351] (H) Apply the default physical channel settings

[0352] (I) Apply the default MAC primary settings to the MCG

[0353] (J) Perform the cell selection process

[0354] Next, the following situation is studied: after the UE 122 sends an RRC connection reconfiguration complete message or an RRC reconfiguration complete message to the target cell during handover processing, the case where data is transmitted and received via the cell groups of both the MCG after handover (also referred to as the Target MCG or the Current MCG) and the MCG of the handover source (Source MCG) (the case of operating in the Dual protocol stack). An example of the processing in this case is shown. It should be noted that the following processing is not limited to the case of the dual protocol stack and can also be applied to other cases.

[0355] First, in the primary cell of the SpCell that is the source MCG, regardless of whether the timer T304 of the source MCG is running under a specific condition (the first condition), the RRC layer processing unit of the UE 122 can start (Start) or restart (Restart) the timer (T310) of the source MCG when it continuously receives notifications of out-of-synchronization from the physical layer processing unit of the source MCG a predetermined number of times (N310 times). In addition, the RRC layer processing unit of the UE 122 can stop (Stop) the timer (T310) when it continuously receives notifications of in-synchronization from the physical layer processing unit of the source MCG a predetermined number of times (N311 times). In addition, in the determination of starting or restarting the timer T310, the conditions that the timer T300, the timer T301, and the timer T311 of the source MCG are not running can be added to the conditions.

[0356] The RRC layer processing unit of the UE 122 determines that a radio link failure is detected in the source MCG when any one of the following conditions (A) to (E) is satisfied.

[0357] (A) When the timer T310 of the source MCG expires (Expire)

[0358] (B) When the timer T312 of the source MCG expires

[0359] (C) When the timers T300, T301, T304, and T311 of the source MCG are not running and a notification (indication) of a random access problem is received from the MAC entity of the source MCG

[0360] (D) When the timer T304 of the source MCG is running under the first condition and a notification of a random access problem is received from the MAC entity of the source MCG

[0361] (E) When a notification indicating that the retransmission of the SRB or DRB has reached the maximum number of retransmissions is received from the RLC layer of the source MCG

[0362] The first condition may be that makeBeforeBreak-r16 is configured for UE122.

[0363] In addition, the first condition may be that either makeBeforeBreak-r14 or makeBeforeBreak-r16 is configured for UE122.

[0364] In addition, the condition (E) may be the following (E2).

[0365] (E2) When none of the timers T300, T301, T304, and T311 of the source MCG are running, upon receiving a notification from the RLC layer of the source MCG indicating that the retransmission of an SRB or DRB has reached the maximum number of retransmissions, or when the timer T304 is running under the first condition, upon receiving a notification from the RLC layer of the source MCG indicating that the retransmission of an SRB or DRB has reached the maximum number of retransmissions

[0366] When UE122 determines that a radio link failure is detected in the source MCG, it may suspend the transmission of some or all of the SRBs and / or DRBs of the source MCG and reset the MAC entity of the source MCG.

[0367] UE122 may regard the MCG as the source MCG when makeBeforeBreak-r16 is configured in the current MCG.

[0368] In addition, UE122 may regard the MCG of the handover source as the source MCG when the first uplink grant is allocated by the PDCCH in the cell of the handover destination.

[0369] In addition, UE122 may regard the MCG of the handover source as the source MCG when the RRC reconfiguration complete message is sent.

[0370] In addition, UE122 may regard the MCG of the handover source as the source MCG when receiving the UE contention resolution identity MAC control element from the target gNB.

[0371] In addition, when makeBeforeBreak-r16 is configured in the current MCG, if there already exists a source MCG, UE122 may release that MCG and regard the current MCG as the new source MCG.

[0372] Thus, it is possible to prevent unnecessary re - establishment processing in MBB - HO by identifying the processing for detecting radio link failure of the source MCG and the processing for detecting radio link failure of the current MCG, and efficient mobility can be achieved.

[0373] An example of the operation of MBB - HO will be described. Here, an example of an RRC re - configuration message using CellGroupConfig including a synchronization re - configuration information element in NR is shown. It should be noted that in the following description of each process, there is a description of receiving an information element. Unless otherwise specified, it may also mean that the information element is included in the RRC re - configuration message that triggers each process. In addition, unless otherwise specified, the information elements used in each process can correspond to the information elements used in Non - Patent Document 10.

[0374] The terminal device performs Process A based on the received CellGroupConfig information element. In addition, the terminal device performs Process L based on the received masterKeyUpdate information element. In addition, the terminal device performs Process I based on the received RadioBearerConfig information element.

[0375] It should be noted that each item of each process described below is marked with indentation and symbols. For example, Process A, Process B, Process C, and Process H are respectively explained in the form of the processes shown in Figure 16 、 Figure 17 、 Figure 18 、 Figure 19 However, other processes are also explained in the same way.

[0376] (Process A) Perform the following processing based on the received CellGroupConfig information element.

[0377] (A - 0) If the CellGroupConfig includes the setting information (spCellConfig information element) of the SpCell including the synchronization re - configuration information, and the synchronization re - configuration information includes information indicating that this RRC re - configuration is MBB - HO (for example, MakeBeforeBreak - r16), then

[0378] (A-0-1)Copy the settings of the current terminal device (source settings) as the target settings. Unless otherwise specifically stated, the following subsequent processing can be performed on the copied target settings. For example, in the case of MBB-HO, the "settings of the current terminal device" for each process can be regarded as the "target settings of the current terminal device". In addition, for example, the settings to be copied may include (1) settings related to bearers (e.g., settings related to SRBs, settings related to DRBs, etc.), (2) settings of cell groups (e.g., settings of SpCell, settings of SCell, settings of each entity, etc.), (3) variables stored inside the terminal device (measurement settings (VarMeasConfig), measurement results (VarMeasReportList), timers, counters, etc.), and (4) settings related to security (e.g., each key), either partially or in whole. In addition, the settings of the bearer to be copied may not include the settings related to SRBs. That is, for DRBs, both the source settings and the target settings can be managed. For SRBs, instead of copying the settings, the settings can be switched from the source settings to the target settings. In addition, the information that can determine whether to copy the SRB settings may be included in the RRC reconfiguration message including synchronous reconfiguration. For example, the above information may be included in MakeBeforeBreak-r16.

[0379] (A-1) If CellGroupConfig includes the settings information (spCellConfig information element) of the SpCell that contains synchronous reconfiguration information, then

[0380] (A-1-1) Perform the subsequent Processing B.

[0381] (A-1-2) If in a suspended state, resume all suspended radio bearers and resume transmission in the SCG for all radio bearers.

[0382] (A-2) If CellGroupConfig includes a list of released RLC bearers (rlc-BearerToReleaseList information element), then

[0383] (A-2-1) Perform the subsequent Processing C.

[0384] (A-3) If CellGroupConfig includes a list of RLC bearers to be added and / or modified (rlc-BearerToAddModList information element), then

[0385] (A-3-1) Perform the subsequent Processing D.

[0386] (A-4) If CellGroupConfig includes the setting of the MAC of this cell group (mac-CellGroupConfig information element), then

[0387] (A-4-1) Set (Config) the MAC entity of this cell group in the subsequent process E. It should be noted that in each embodiment of the present invention, the terminal device uses the information element included in the RRC message for "setting", which may be applying the information included in the information element to the setting of the terminal device.

[0388] (A-5) If CellGroupConfig includes the list of SCell to be released (sCellToReleaseList information element), then

[0389] (A-5-1) Perform the release of the SCell in the subsequent process F.

[0390] (A-6) If CellGroupConfig includes the setting information of the SpCell (spCellConfig information element), then

[0391] (A-6-1) Set the SpCell in the subsequent process G.

[0392] (A-7) If CellGroupConfig includes the list of SCell to be added and / or changed (sCellToAddModList information element), then

[0393] (A-7-1) Perform the addition and / or change of the SCell in the subsequent process H.

[0394] (Process B)

[0395] (B-1) If the security of the AS is not activated, perform the process of transitioning to RRC IDLE and end process B.

[0396] (B-2) If it is running, stop the timer T310 of the corresponding SpCell.

[0397] (B-3) Start the timer T304 of the corresponding SpCell by resetting the timer value of t304 included in the synchronization reset.

[0398] (B-4) If it includes frequency information (frequencyInfoDL), then

[0399] (B-4-1) Consider the target SpCell as a cell with a physical cell identifier represented by the physical cell identifier information (physCellId) included in the synchronization reset at the SSB frequency represented by frequencyInfoDL.

[0400] (B-5) Otherwise,

[0401] (B-5-1) Consider the target SpCell as a cell with a physical cell identifier represented by the physical cell identifier information (physCellId) included in the synchronization reset at the SSB frequency of the source SpCell.

[0402] (B-6) Initiate the synchronization of the target SpCell to the downlink.

[0403] (B-7) Apply the established BCCH settings.

[0404] (B-8) If necessary, obtain the Master Information Block (MIB) as one of the broadcast information.

[0405] (B-9) If the information represented as MBB-HO is included in the synchronization reset,

[0406] (B-9-1) If there is no MAC entity in the target cell group,

[0407] (B-9-1-1) Generate a MAC entity for the target cell group (referred to only as the target MAC entity).

[0408] (B-9-2) Apply the established (default) MAC cell group settings to the target MAC entity.

[0409] (B-9-3) If set, consider the SCell of the target cell group as in the Deactivated state.

[0410] (B-9-4) Use the value of newUE-Identity as the C-RNTI for the target cell group.

[0411] (B-10) Otherwise,

[0412] (B-10-1) Reset the MAC entity of the cell group.

[0413] (B-10-2) If set, consider the SCell of the cell group as in the Deactivated state.

[0414] (B-10-3) Apply the value of newUE-Identity as the C-RNTI for the cell group.

[0415] (B-11) Configure the lower layer based on the configuration of the SpCell (spCellConfigCommon) included in the synchronization reconfiguration.

[0416] (B-12) If necessary, configure the lower layer based on other information included in the synchronization reconfiguration.

[0417] (Procedure C)

[0418] (C-1a) As part of the current configuration of the terminal device, for each value of the logical channel identifier (logicalChannelIdentity) included in the rlc-BearerToReleaseList, or

[0419] (C-1b) As a result of the release of the SCG, for each value of the released logical channel identifier,

[0420] (C-1-1) Release the corresponding logical channel and the RLC entity associated with the logical channel.

[0421] (Procedure D)

[0422] Perform the following procedures for each configuration of the RLC bearer (RLC-BearerConfig) included in the received rlc-BearerToAddModList information element.

[0423] (D-1) If the current configuration of the terminal device includes an RLC bearer for the received logical channel identifier,

[0424] (D-1-1) If information indicating the reestablishment of the RLC (reestablishRLC) is received, then

[0425] (D-1-1-1) Reestablish the RLC entity

[0426] (D-1-2) Reconfigure the RLC entity according to the received RLC configuration (rlc-Config).

[0427] (D-1-3) Reconfigure the logical channel according to the received MAC logical channel configuration (mac-LogicalChannelConfig).

[0428] (D-2) Otherwise,

[0429] (D-2-1) If the logical channel identifier and RLC configuration for the SRB are included, then

[0430] (D-2-1-1) Establish an RLC entity according to the established (default) settings.

[0431] (D-2-2) Otherwise,

[0432] (D-2-2-1) Establish an RLC entity according to the received RLC settings (rlc-Config).

[0433] (D-2-3) If the logical channel identifier for the SRB and the MAC logical channel settings are included, then

[0434] (D-2-3-1) Set the MAC entity corresponding to the logical channel according to the established (default) settings.

[0435] (D-2-4) Otherwise,

[0436] (D-2-4-1) Set the MAC entity corresponding to the logical channel according to the received MAC logical channel settings.

[0437] (D-2-5) Based on the radio bearer identifier information (servedRadioBearer) included in the RLC bearer settings, establish a correspondence between the logical channel and the PDCP entity.

[0438] (Process E)

[0439] (E-1) If the reconfiguration object of CellGroupConfig is the SCG and the SCG MAC is not part of the current UE settings, then

[0440] (E-1-1) Generate an SCG MAC entity.

[0441] (E-2) Reconfigure the main configuration of the cell group MAC according to the MAC cell group settings (mac-Cell) except for the settings related to the addition, modification, and / or release of the timing advance group (TAG).

[0442] (E-3) If the received MAC cell group settings include information related to the release of the TAG (tag-ToReleaseList),

[0443] (E-3-1) If the identifier of the TAG included in tag-ToReleaseList is part of the current UE settings, release the TAG represented by the identifier of the TAG for each identifier of the TAG.

[0444] (E-4) If the received MAC cell group configuration includes information related to addition and / or modification of a TAG (tag-ToAddModList),

[0445] (E-4-1) If the identifier of the TAG included in the tag-ToAddModList is not part of the current terminal device's configuration, then for each identifier of the TAG,

[0446] (E-4-1-1) Add a TAG corresponding to the identifier of the TAG according to the received timing advance timer.

[0447] (E-4-2) If the identifier of the TAG included in the tag-ToAddModList is part of the current terminal device's configuration, then for each identifier of the TAG,

[0448] (E-4-2-1) Reset the TAG corresponding to the identifier of the TAG according to the received timing advance timer.

[0449] (Procedure F)

[0450] (F-1) If the release is triggered by receiving a release list of SCell (sCellToReleaseList), then

[0451] (F-1-1) For each value of the SCell index (sCellIndex) included in the sCellToReleaseList,

[0452] (F-1-1-1) If the existing terminal device's configuration includes an SCell having the value of sCellIndex, then

[0453] (F-1-1-1-1) Release the SCell.

[0454] (Procedure G)

[0455] (G-1) If the SpCell configuration includes information on timers and constants related to radio link failure (RLF) (rlf-TimersAndConstants), then

[0456] (G-1-1) Set the timers and constants for RLF of the cell group according to the rlf-TimersAndConstants.

[0457] (G-2) Otherwise, if rlf-TimersAndConstants is not configured for the cell group, then

[0458] (G-2-1) Use the timer and constant values received through system information to set the timer and constant for RLF of this cell group.

[0459] (G-3) If the SpCell configuration includes dedicated SpCell configuration (spCellConfigDedicated), then

[0460] (G-3-1) Set the SpCell according to spCellConfigDedicated.

[0461] (G-3-2) If the setting is made, consider the BWP indicated by the identifier of the first active uplink BWP (firstActiveUplinkBWP-Id) as the active uplink BWP.

[0462] (G-3-3) If the setting is made, consider the BWP indicated by the identifier of the first active downlink BWP (firstActiveDownlinkBWP-Id) as the active downlink BWP.

[0463] (G-3-4) If the reference signal for wireless link monitoring is reconfigured according to the received dedicated SpCell configuration,

[0464] (G-3-4-1) If it is running, stop the timer T310 corresponding to the SpCell.

[0465] (G-3-4-2) Stop the counters N310 and N311.

[0466] (Procedure H)

[0467] (H-1) For each value of sCellIndex included in sCellToAddModList that is not part of the current terminal device's configuration,

[0468] (H-1-1) Append the SCell corresponding to sCellIndex.

[0469] (H-1-2) Configure the lower layer in such a way that the SCell is considered in an inactive state.

[0470] (H-1-3) For the measurement identifier of each list (measIdList) of measurement identifiers of variables (VarMeasConfig) that save measurement configurations,

[0471] (H-1-3-1a) If the SCell cannot be applied to the measurement corresponding to the measurement identifier, and

[0472] (H-1-3-1b) If the SCell is included in the list of triggered cells (cellsTriggeredList) defined by the variable (VarMeasReportList) that stores the measurement report for the measurement identifier, then

[0473] (H-1-3-1-1) Delete the SCell from the list of triggered cells (cellsTriggeredList) defined by the variable (VarMeasReportList) that stores the measurement report for the measurement identifier.

[0474] (H-2) For each value of sCellIndex included in sCellToAddModList that is part of the current terminal device settings,

[0475] (H-2-1) Change the settings of the SCell corresponding to sCellIndex.

[0476] (Processing I)

[0477] (I-1) If RadioBearerConfig includes srb3-ToRelease, then

[0478] (I-1-1) Release the PDCP entity and SRB identifier of SRB3.

[0479] (I-2) If RadioBearerConfig includes SRB-ToAddModList, then

[0480] (I-2-1) Perform addition and / or reconfiguration of SRBs.

[0481] (I-3) If RadioBearerConfig includes drb-ToReleaseList, then

[0482] (I-3-1) Perform the release of DRBs in the subsequent Processing J.

[0483] (I-4) If RadioBearerConfig includes DRB-ToAddModList, then

[0484] (I-4-1) Perform addition and / or reconfiguration of DRBs in the subsequent Processing K.

[0485] (I-5) Release all SDAP entities that are not associated with the DRB, and notify the upper layer of the release of the user plane resources of the PDU session associated with the released SDAP entity.

[0486] In the process I, in the case of MBB-HO, in the process of adding, reconfiguring, and / or releasing the SRB, the settings of both the source and the target can be managed. Instead of performing processes I-1 and I-2 on the target settings, the current SRB settings are reconfigured in processes I-1 and I-2. That is, the SRB can manage one setting. In this case, the SRB settings of the source before reconfiguration for resetting can be saved separately in case of handover failure or the like.

[0487] As the process I-5, in the case of MBB-HO, all SDAP entities that are not associated with either the DRB of the source setting or the DRB of the target setting can be released, and the upper layer is notified of the release of the user plane resources of the PDU session associated with the released SDAP entity. For example, MBB-HO can be performed based on an RRC reconfiguration message including synchronous reconfiguration. In the target cell, until a message for releasing the source setting (such as an RRC message, a MAC CE, etc.) is received, the SDAP entities associated with either or both of the source DRB and the target DRB are not released. Instead, when a message for releasing the source setting is received to release the source DRB, all SDAP entities that are not associated with the (target) DRB are released, and the upper layer is notified of the release of the user plane resources of the PDU session associated with the released SDAP entity.

[0488] The above "receiving a message for releasing the source setting" can be renamed as detecting a certain request. The certain request can be renamed as a certain piece of information. Detecting a certain request can be that a specific information element (such as an information element indicating the release of the source setting) is included in the received RRC message, or that specific information (such as information indicating the release of the source setting) is included in the received MAC control element, or that the first uplink grant is received in the SpCell. Detecting a certain request can be that the random access process has been successful. Detecting a certain request can also be in either or both of the cases where (A) synchronous reconfiguration is included in the SpCellConfig and (B) the random access process is triggered by the RRC entity providing (submitting) a message for notifying the completion of the RRC reconfiguration (for example, in LTE, it is the RRC connection reconfiguration complete message, and in NR, it is the RRC reconfiguration complete message) to the lower layer. In addition, detecting a certain request can also be any one detected by installing the terminal device.

[0489] (Processing J)

[0490] (J-1a) For each DRB identifier included in the drb-ToReleaseList that is part of the current configuration of the terminal device, or

[0491] (J-1b) For each DRB identifier that is released as a result of the overall configuration,

[0492] (J-1-1) Release the PDCP entity and the DRB identifier.

[0493] (J-1-2) If there is an SDAP entity associated with the DRB, then

[0494] (J-1-2-1) Indicate the release of the DRB to the SDAP associated with the DRB.

[0495] (J-1-3) If the DRB is associated with an EPS bearer identifier,

[0496] (J-1-3-1) If a new bearer is not added to either NR or E-UTRA with the same EPS bearer identifier, then

[0497] (J-1-3-1-1) Notify the upper layer of the release of the DRB and the EPS bearer identifier of the released DRB.

[0498] As the processing of J-1-3-1, in the case of MBB-HO, if for the same EPS bearer, a new bearer is not added to either the source or the target configuration, the release of the DRB and the EPS bearer identifier of the released DRB can be notified to the upper layer. For example, MBB-HO can be performed based on an RRC reconfiguration message including synchronous reconfiguration. In the target cell, until a message for releasing the source configuration (such as an RRC message, MAC CE, etc.) is received, if for the same EPS bearer, no bearer association is made in either the source or the target configuration, the release of the DRB and the EPS bearer identifier of the released DRB are not notified to the upper layer. Instead, when a message for releasing the source configuration and the source DRB are received, if a new bearer is not added to either NR or E-UTRA with the same EPS bearer identifier, the release of the DRB and the EPS bearer identifier of the released DRB are notified to the upper layer.

[0499] (Processing K)

[0500] (K-1) For each DRB identifier included in the DRB-ToAddModList that is not part of the current configuration of the terminal device,

[0501] (K-1-1) Establish a PDCP entity and configure the PDCP entity according to the received PDCP configuration (pdcp-Config).

[0502] (K-1-2) If the PDCP entity for this DRB is not configured through cipheringDisabled,

[0503] (K-1-2-1a) If the target RAT for handover is E-UTRA / 5GC, or

[0504] (K-1-2-1b) If the terminal device is only connected to E-UTRA / 5GC, then

[0505] (K-1-2-1-1) Configure the PDCP entity using the encryption algorithm and key configuration of Non-Patent Document 4.

[0506] (K-1-2-2) Otherwise,

[0507] (K-1-2-2-1) Configure the PDCP entity through the encryption algorithm according to the security configuration (securityConfig), and apply the key represented by the parameter (keyToUse) associated with the master key (KeNB or KgNB) or the secondary key (S-KgNB).

[0508] (K-1-3) If the PDCP entity for this DRB is configured to perform integrity protection, then

[0509] (K-1-3-1) Configure the PDCP entity through the integrity protection algorithm according to the security configuration (securityConfig), and apply the key represented by the parameter (keyToUse) associated with the master key (KeNB or KgNB) or the secondary key (S-KgNB).

[0510] (K-1-4) If the SDAP configuration (sdap-Config) is included,

[0511] (K-1-4-1) If there is no SDAP for the received PDU session,

[0512] (K-1-4-1-1) Establish an SDAP entity.

[0513] (K-1-4-1-2) If there was no SDAP for the received PDU session before this reconfiguration,

[0514] (K-1-4-1-2-1) Notify the upper layer of the establishment of the user plane resources for this PDU session.

[0515] (K-1-4-2) Set the SDAP entity according to the received SDAP setting, and associate the DRB with the SDAP entity.

[0516] (K-1-5) If the DRB is associated with an EPS bearer identifier,

[0517] (K-1-5-1) If, within the same EPS bearer identifier, the DRB was set via NR or E-UTRA before receiving this reconfiguration, then

[0518] (K-1-5-1-1) Associate the established DRB with the corresponding EPS bearer identifier.

[0519] (K-1-5-2) Otherwise,

[0520] (K-1-5-2-1) Notify the upper layer of the establishment of the DRB and the EPS bearer identifier of the established DRB.

[0521] (K-2) For each DRB identifier included in the DRB-ToAddModList that is part of the current configuration of the terminal device,

[0522] (K-2-1) If the parameter reestablishPDCP is set,

[0523] (K-2-1-1a) If the target RAT for the handover is E-UTRA / 5GC, or

[0524] (K-2-1-1b) If the terminal device is connected only to E-UTRA / 5GC,

[0525] (K-2-1-1-1) If the PDCP entity of the DRB is not set with cipheringDisabled,

[0526] (K-2-1-1-1-1) Set the PDCP entity using the encryption algorithm and key settings of Non-Patent Document 4.

[0527] (K-2-1-2) Otherwise,

[0528] (K-2-1-2-1) If the PDCP entity of this DRB is not set with cipheringDisabled,

[0529] (K-2-1-2-1-1) Set the PDCP entity via the encryption algorithm according to the security configuration, and apply the key represented by the parameter keyToUse associated with the master key (KeNB or KgNB) or the secondary key (S-KgNB).

[0530] (K-2-1-2-2) If the PDCP entity of the DRB is configured to perform integrity protection, then

[0531] (K-2-1-2-2-1) Configure the PDCP entity according to the integrity protection algorithm of the security configuration (securityConfig), and apply the key indicated by the parameter (keyToUse) associated with the master key (KeNB or KgNB) or the secondary key (S-KgNB).

[0532] (K-2-1-3) If drb-ContinueROHC is included in pdcp-Config, then

[0533] (K-2-1-3-1) Notify the lower layer that drb-ContinueROHC is configured.

[0534] (K-2-1-4) Re-establish the PDCP entity of the DRB.

[0535] (K-2-2) Otherwise, if recoverPDCP is configured, then

[0536] (K-2-2-1) Trigger the execution of data recovery for the PDCP entity of the DRB.

[0537] (K-2-3) If PDCP configuration is included, then

[0538] (K-2-3-1) Re-configure the PDCP entity according to the received PDCP configuration.

[0539] (K-2-4) If SDAP configuration is included, then

[0540] (K-2-4-1) Re-configure the SDAP entity according to the received SDAP configuration.

[0541] (K-2-4-2) For each QFI added by mappedQoS-FlowsToAdd, if the value of QFI is configured, release the value of QFI from the old DRB.

[0542] As the process K-1-4-1-2, in the case of MBB-HO, if the SDAP of the received PDU session does not exist in the configurations of both the source and the target before receiving this re-configuration, the establishment of the user plane resources for this PDU session can be notified to the upper layer. Alternatively, as the process K-1-4-1-2, in the case of MBB-HO, if the SDAP of the received PDU session does not exist in the configuration of the source before receiving this re-configuration, the establishment of the user plane resources for this PDU session is notified to the upper layer.

[0543] In the process K-1-5-2, in the case of MBB-HO, if before receiving the reconfiguration, no DRB is configured for the same bearer identifier by NR or E-UTRA in both the source configuration and the target configuration, the establishment of the DRB and the EPS bearer identifier of the established DRB can be notified to the upper layer. Alternatively, in the process K-1-5-2, in the case of MBB-HO, if before receiving the reconfiguration, no DRB is configured for the same bearer identifier by NR or E-UTRA in the source configuration, the establishment of the DRB and the EPS bearer identifier of the established DRB can be notified to the upper layer.

[0544] (Process L)

[0545] (L-1) If the terminal device is connected to E-UTRA / EPC,

[0546] (L-1-1) If sk-Counter is included,

[0547] (L-1-1-1) Update the S-KgNB key based on the KgNB key and the received sk-Counter.

[0548] (L-1-1-2) Generate (Derive) the KRRCenc key and the KUPenc key. The KRRCenc key is the key used to protect the RRC signal generated from the KgNB through the encryption algorithm. In addition, KUPenc is the key used to protect the user plane traffic (user data) generated from the KgNB through the encryption algorithm.

[0549] (L-1-1-3) Generate the KRRCint key and the KUPint key based on the KgNB key. The KRRCint key is the key used to protect the RRC signal generated from the KgNB through the integrity algorithm. In addition, KUPint is the key used to protect the user plane traffic (user data) generated from the KgNB through the integrity algorithm.

[0550] (L-2) Otherwise,

[0551] (L-1-2) If the received masterKeyUpdate includes nas-Container,

[0552] (L-1-2-1) Forward the nas-Container to the upper layer.

[0553] (L-1-3) If the keySetChangeIndicator is "true", then

[0554] (L-1-3-1) Generate or update KgNB based on KAMF.

[0555] (L-1-4) Otherwise,

[0556] (L-1-4-1) Generate or update the KgNB key based on the current KgNB key or NextHop (NH).

[0557] (L-1-5) Store the value of nextHopChainingCount.

[0558] (L-1-6) Generate the key associated with the KgNB key in the following manner.

[0559] (L-1-6-1) If securityAlgorithmConfig is included in SecurityConfig, then

[0560] (L-1-6-1-1) Generate the KRRCenc key and KUPenc key associated with the cipheringAlgorithm included in securityAlgorithmConfig based on the KgNB key.

[0561] (L-1-6-1-2) Generate the KRRCint key and KUPint key associated with the integrityProtAlgorithm included in securityAlgorithmConfig based on the KgNB key.

[0562] (L-1-6-2) Otherwise,

[0563] (L-1-6-2-1) Generate the KRRCenc key and KUPenc key associated with the current cipheringAlgorithm based on the KgNB key.

[0564] (L-1-6-2-2) Generate the KRRCint key and KUPint key associated with the current integrityProtAlgorithm based on the KgNB key.

[0565] An example of the operation of MBB-HO is described. Here, an example of using an RRC connection reconfiguration message including a mobilityControlInfo information element in LTE is shown. It should be noted that in the descriptions of the following respective processes, there is a description of receiving an information element, but unless otherwise specified, it may also mean that the information element is included in the RRC connection reconfiguration message that triggers each process. In addition, unless otherwise specified, the information elements used in each process may correspond to the information elements used in Non-Patent Document 4.

[0566] The terminal device receives an RRC connection reconfiguration message including mobilityControlInfo, and if the terminal device can comply with the settings included in the message, it performs the following process LA.

[0567] (Process LA)

[0568] (LA-1) Start timer T304 using the timer value of t304 included in mobilityControlInfo.

[0569] (LA-2) If carrierFreq is included, then

[0570] (LA-2-1) The physical cell identifier on the frequency indicated by carrierFreq regards the cell indicated by targetPhysCellId as the target PCell.

[0571] (LA-3) Otherwise,

[0572] (LA-3-1) The physical cell identifier on the frequency of the source PCell regards the cell indicated by targetPhysCellId as the target PCell.

[0573] (LA-4) Start synchronization of the downlink to the target PCell.

[0574] (LA-5-1) After the terminal device stops the uplink transmission and / or downlink reception with the source cell, it performs the remaining processes of the subsequent process including the reset of MAC.

[0575] (LA-6) If makeBeforeBreak-r16 is set, then

[0576] (LA-6-1)Copy the settings of the current terminal device (source settings) as the target settings. Unless otherwise specifically stated, the following subsequent reconfiguration processes can be performed on the copied target settings. For example, in the case of MBB-HO, the "settings of the current terminal device" for each process can be regarded as the "target settings of the current terminal device". In addition, for example, the settings to be copied may include (1) bearer settings (e.g., SRB settings, DRB settings, etc.), (2) cell group settings (e.g., SpCell settings, SCell settings, RLC entity settings, MAC entity settings, PHY settings, etc.), (3) internal variables (measurement settings (VarMeasConfig), measurement results (VarMeasReportList), timers, counters, etc.), (4) part or all of the security-related settings (e.g., each key). In addition, the SRB settings may not be included in the bearer settings to be copied. That is, for DRB, both the source settings and the target settings can be managed. For SRB, instead of copying the settings, the settings are switched from the source settings to the target settings. In addition, the information that can determine whether to copy the SRB settings may be included in the RRC connection reconfiguration message including mobilityControlInfo. For example, the above information may be included in MakeBeforeBreak-r16.

[0577] (LA-7)If settings are made, reset the MAC of MCG and the MAC of SCG. The case where MakeBeforeBreak-r16 is set may be that the MAC of the source MCG and the MAC of SCG are not reset. Or, in the case where MakeBeforeBreak-r16 is set, here, instead of resetting the source MAC, the target MAC can be reset.

[0578] (LA-8)Re-establish PDCP for all radio bearers configured and established through PDCP settings. In the case where MakeBeforeBreak-r16 is set, the re-establishment of PDCP is only applied to the target PDCP. Or, in the case of the subsequent Single PDCP, if MakeBeforeBreak-r16 is set, if there is already a PDCP associated with the target radio bearer, the establishment and / or re-establishment of PDCP may not be performed. That is, if MakeBeforeBreak-r16 is set, if there is no PDCP associated with the target radio bearer, the establishment and / or re-establishment of PDCP can be performed.

[0579] (LA-9) For all established radio bearers, if configured, re-establish the RLC of MCG and the RLC of SCG.

[0580] (LA-10) Use the value of newUE-Identity as the C-RNTI.

[0581] (LA-11) Configure the lower layers according to the received radio resource configuration common to the cell.

[0582] (LA-12) Configure the lower layers according to other information included in the received mobilityControlInfo.

[0583] (LA-13) If the received RRC connection reconfiguration message includes sCellToReleaseList,

[0584] (LA-13-1) Perform the release of the sCell.

[0585] (LA-14) If the received RRC connection reconfiguration message includes sCellGroupToReleaseList,

[0586] (LA-14-1) Perform the release of the sCell group.

[0587] (LA-15a) If the received RRC connection reconfiguration message includes scg-Configuration, or

[0588] (LA-15b) If the current configuration of the terminal device includes more than one Split DRB and the received RRC connection reconfiguration message includes DRB-ToAddModList,

[0589] (LA-15-1) Perform the reconfiguration of the SCG.

[0590] (LA-16) If the received RRC connection reconfiguration message includes the radio resource configuration dedicated to the terminal device,

[0591] (LA-16-1) Perform the radio resource configuration in the subsequent process LB.

[0592] (LA-17) If the RRC connection reconfiguration message includes the security configuration (securityConfigHO-v1530),

[0593] (LA-17-1) If a nas-Container is received, then

[0594] (LA-17-1-1) Forward the nas-Container to the upper layer.

[0595] (LA-17-2) If a keyChangeIndicator-r15 is received and the keyChangeIndicator-r15 is "true", then

[0596] (LA-17-2-1) Update the KeNB key based on the KAMF key.

[0597] (LA-17-3) Otherwise,

[0598] (LA-17-3-1) Update the KeNB key based on the current KeNB or NextHop (NH).

[0599] (LA-17-4) Store the value of nextHopChainingCount-r15.

[0600] (LA-17-5) If a securityAlgorithmConfig-r15 is received, then

[0601] (LA-17-5-1) Generate a KRRCint key associated with the received integrityProtAlgorithm.

[0602] (LA-17-5-2) Generate a KRRCenc key and a KUPenc key associated with the received cipheringAlgorithm. The KRRCenc key is the key used to protect the RRC signal generated from the KeNB through the encryption algorithm. In addition, KUPenc is the key used to protect the traffic (user data) of the user plane generated from the KeNB through the encryption algorithm.

[0603] (LA-17-6) Otherwise,

[0604] (LA-17-6-1) Generate a KRRCint key associated with the current integrityProtAlgorithm according to the KeNB key.

[0605] (LA-17-6-2) Generate a KRRCenc key and a KUPenc key associated with the current cipheringAlgorithm according to the KeNB key.

[0606] (LA-18) If the received RRC connection reconfiguration message includes sCellToAddModList, then

[0607] (LA-18-1) Perform addition and / or modification of SCell.

[0608] (LA-19) If the received RRC connection reconfiguration message includes sCellGroupToAddModList, then

[0609] (LA-19-1) Perform addition and / or modification of SCell group.

[0610] (LA-20) If the received RRC connection reconfiguration message includes measConfig, then (LA-20-1) Perform measurement configuration.

[0611] (LA-21) Perform automatic deletion of measurement identifier.

[0612] (LA-22) Provide the RRC connection reconfiguration complete message to the lower layer for transmission.

[0613] (LA-23) If MAC is successful in the random access procedure, then

[0614] (LA-23-1) Stop timer T304 and end the procedure.

[0615] (Handling LB)

[0616] (LB-1) If the received radioResourceConfigDedicated includes SRB-ToAddModList, then

[0617] (LB-1-1) Then perform addition and / or reconfiguration of SRB in the subsequent handling LC.

[0618] (LB-2) If the received radioResourceConfigDedicated includes drb-ToReleaseList, then

[0619] (LB-2-1) Perform DRB release in the subsequent handling LD.

[0620] (LB-3) If the received radioResourceConfigDedicated includes DRB-ToAddModList, then

[0621] (LB-3-1) Perform addition and / or reconfiguration of DRB in the subsequent handling LE.

[0622] (LB-4) If the received radioResourceConfigDedicated includes mac-MainConfig, then

[0623] (LB-4-1) Execute the main setting of MAC in the subsequent process LF.

[0624] (Process LC)

[0625] (LC-1) For each SRB identifier included in the SRB-ToAddModList that is not part of the current terminal device's settings,

[0626] (LC-1-1) Establish a PDCP entity through the current security settings.

[0627] (LC-1-2) If rlc-BearerConfigSecondary with a value of "configured" is received, then

[0628] (LC-1-2-1) Establish a secondary MCG RLC entity according to the received rlc-BearerConfigSecondary and associate it with the DCCH logical channel.

[0629] (LC-1-2-2) Configure the PDCP entity for E-UTRA in the active replication mode.

[0630] (LC-2) For each SRB identifier included in the SRB-ToAddModList that is part of the current terminal device's settings,

[0631] (LC-2-1) If pdcp-verChange is included (i.e., change from NR PDCP to E-UTRA PDCP), then

[0632] (LC-2-1-1) Establish an E-UTRA PDCP entity through the current security settings.

[0633] (LC-2-1-2) Associate the main RLC of this SRB with the established PDCP entity.

[0634] (LC-2-1-3) Release the NR PDCP of this SRB.

[0635] (LC-2-2) Reconfigure the main RLC entity according to the received rlc-Config.

[0636] (LC-2-3) Reconfigure the main DCCH logical channel according to the received logical channel configuration (logicalChannelConfig).

[0637] (LC-2-4) If the rlc-BearerConfigSecondary includes "release" as the value,

[0638] (LC-2-4-1) Release the secondary MCG RLC entity and the DCCH logical channel associated therewith.

[0639] (LC-2-5) If the rlc-BearerConfigSecondary with "configure" as the value is received,

[0640] (LC-2-5-1) If the secondary RLC bearer is not included in the existing SRB setting,

[0641] (LC-2-5-1-1) Establish a secondary MCG RLC entity according to the received rlc-BearerConfigSecondary and associate it with the DCCH logical channel.

[0642] (LC-2-5-1-2) Configure the PDCP entity for E-UTRA in the way of active duplication.

[0643] (LC-2-5-2) Otherwise,

[0644] (LC-2-5-2-1) Re-configure the secondary MCG RLC entity according to the received rlc-BearerConfigSecondary to associate it with the DCCH logical channel.

[0645] (Process LD)

[0646] (LD-1a) For each DRB identifier included in the drb-ToReleaseList which is part of the current setting of the terminal device, or,

[0647] (LD-2b) For each value of the DRB identifier released as a result of the full setting,

[0648] (LD-2-1) If the release of the DRB is the result of the full setting,

[0649] (LD-2-1-1) Release the PDCP entity of E-UTRA or NR.

[0650] (LD-2-2) Otherwise, if the DRB is configured with a PDCP setting,

[0651] (LD-2-2-1) Release the PDCP entity of E-UTRA.

[0652] (LD-2-3) Otherwise,

[0653] (LD-2-3-1) Re - establish the RLC entity for this DRB.

[0654] (LD-2-4) Release the RLC entity.

[0655] (LD-2-5) Release the DTCH logical channel.

[0656] (LD-2-6) If the terminal device is connected to the EPC,

[0657] (LD-2-6-1) If the DRB is configured with PDCP settings and a new DRB is added in the same EPS bearer identifier through any one of DRB - ToAddModList, nr - radioBearerConfig1, or nr - radioBearerConfig2,

[0658] (LD-2-6-1-1) If this process is triggered by handover, then

[0659] (LD-2-6-1-1-1) After successful handover, notify the upper layer of the release of the DRB and the EPS bearer identifier of the released DRB.

[0660] (LD-2-6-1-2) Otherwise,

[0661] (LD-2-6-1-2-1) Immediately notify the upper layer of the release of the DRB and the EPS bearer identifier of the released DRB.

[0662] (Process LE)

[0663] (LE-1) For each DRB identifier included in the DRB - ToAddModList that is not part of the current terminal device configuration,

[0664] (LE-1-1) If the value of DRB - ToAddModListSCG is not received or the DRB identifier is not included in DRB - ToAddModListSCG,

[0665] (LE-1-1-1) If pdcp - Config is included, establish the PDCP entity according to pdcp - Config and configure it with the security settings of the current MCG.

[0666] (LE-1-1-2) If r1c - Confi is included, establish MCGRLC according to rlc - Config.

[0667] (LE-1-1-3) If a logical channel identifier (logicalChannelIdentity) and a logical channel configuration (logicalChannelConfig) are included, then an MCG DTCH logical channel is established according to the logicalChannelIdentity and the logicalChannelConfig.

[0668] (LE-1-1-4) If an rlc-BearerConfigSecondary with "configured" as the value is included, then

[0669] (LE-1-1-4-1) According to the rlc-BearerConfigSecondary, a secondary MCG RLC entity is established and associated with the DTCH logical channel. Then, the established RLC entity is associated with the E-UTRA PDCP having the same DRB identifier value in the settings of the current terminal device.

[0670] (LE-1-2) If a DRB is set in the same EPS bearer identifier, then

[0671] (LE-1-2-1) The established DRB is associated with the EPS bearer identifier.

[0672] (LE-1-3) Otherwise, if an entry in the DRB-ToAddModList includes pdcp-config (i.e., a bearer is established in the PDCP of E-UTRA), then

[0673] (LE-1-3-1) Notify the upper layer of the establishment of the DRB and the EPS bearer identifier of the established DRB.

[0674] (LE-2) For each DRB identifier included in the DRB-ToAddModList that is part of the settings of the current terminal device, then

[0675] (LE-2-1) Reset each layer and / or bearer according to the included settings.

[0676] (Process LF)

[0677] (LF-1) Reset the main configuration of the MAC (MAC mainconfiguration) according to the MA main configuration information element (mac-MainConfig) except for the settings related to the addition, modification, and / or release of the secondary timing advance group (STAG).

[0678] (LF-2) If the received mac-MainConfig includes information related to the release of STAG (stag-ToReleaseList),

[0679] (LF-2-1) If the identifier of the STAG included in the stag-ToReleaseList is part of the setting of the current terminal device, release the STAG represented by the identifier of each STAG.

[0680] (LF-3) If the received mac-MainConfig includes information related to the addition and / or modification of STAG (stag-ToAddModList),

[0681] (LF-3-1) If the identifier of the STAG included in the stag-ToAddModList is not part of the setting of the current terminal device, for each identifier of the TAG,

[0682] (LF-3-1-1) Add the STAG corresponding to the identifier of the STAG according to the received timeAlignmentTimerSTAG.

[0683] (LF-3-2) If the identifier of the STAG included in the stag-ToAddModList is part of the setting of the current terminal device, for each identifier of the STAG,

[0684] (LF-3-2-1) Reset the STAG corresponding to the identifier of the STAG according to the received timeAlignmentTimerSTAG.

[0685] Another example of the operation of MBB-HO is described. Here, an example of using an RRC reconfiguration message including conditional handover settings in NR is shown.

[0686] For example, the RRC message sent by the base station device may include a conditional handover information element. The conditional handover information element may include a list containing one or more information elements (conditional handover settings) including the information included in the synchronization reconfiguration information element. In addition, the conditional handover information element may include an information element (conditional handover condition) indicating the conditions for applying the conditional handover settings to each conditional handover setting or a part or all of the conditional handover settings.

[0687] The conditional handover setting may include part or all of the information included in RadioBearerConfig and CellGroupConfig. In addition, the conditional handover setting may include information indicating MBB-HO. In addition, the conditional handover condition may include threshold information for using a reference signal to determine whether the condition is met. In addition, the conditional handover condition may also include information indicating immediate application of the conditional handover setting. For example, when the conditional handover condition indicates information for immediate application of the conditional handover setting and information indicating MBB-HO is added to the conditional handover setting, the processes A and I are executed based on the information included in the conditional handover setting, thereby enabling MBB-HO. Of course, when the condition is also met even when the conditional handover condition is other conditions, the processes A and I are executed based on the information included in the conditional handover setting, thereby enabling conditional MBB-HO.

[0688] In the MBB-HO of the NR, the terminal device may adopt a configuration of a single PDCP (SinglePDCP) that is common to the source and the target.

[0689] For example, when the core network is 5GC, in the source setting, through the RLC bearer setting, the logical channel, DRB (or SRB), and RLC bearer are associated, and then through drb-ToAddMod, the DRB, PDCP entity, and PDU session are associated. Similarly, in the target setting, through the RLC bearer setting, the logical channel, DRB (or SRB), and RLC bearer are associated, and then through drb-ToAddMod, the DRB (or SRB), PDCP entity, and PDU session are associated. In this case, for example, the logical channels, DRBs (or SRBs), and / or RLC bearers associated with the same DRB identifier (or SRB identifier) in the source setting and the target setting may be associated with one PDCP. In addition, for example, the logical channels, DRBs (or SRBs), and / or RLC bearers associated with the same PDU session in the source setting and the target setting may be associated with one PDCP.

[0690] For example, in the case where the core network is 5GC, in the source configuration, through RLC bearer configuration, the logical channel, DRB (or SRB), and RLC bearer are associated, and then through drb-ToAddMod, the DRB, PDCP entity, and PDU session are associated. Similarly, in the target configuration, through RLC bearer configuration, the logical channel, DRB (or SRB), and RLC bearer are associated, and then through drb-ToAddMod, the DRB (or SRB), PDCP entity, and PDU session are associated. In this case, for example, the logical channels, DRBs (or SRBs), and / or RLC bearers associated with the same DRB identifier (or SRB identifier) in the source configuration and the target configuration can be associated with one SDAP.

[0691] In addition, for example, in the case where the core network is EPC, in the source configuration, the DRB (or SRB), PDCP entity, logical channel, RLC entity (and / or RLC bearer), and EPS bearer are associated. Similarly, in the target configuration, the DRB (or SRB), PDCP entity, logical channel, RLC entity (and / or RLC bearer), and EPS bearer are also associated. In this case, for example, the logical channels, RLC entities (and / or RLC bearers) associated with the same DRB identifier (or SRB identifier) in the source configuration and the target configuration can be associated with one PDCP entity. In addition, for example, the logical channels, RLC entities (and / or RLC bearers), DRBs (or SRBs) associated with the same EPS bearer identifier in the source configuration and the target configuration can be associated with one PDCP.

[0692] In the above cases, the terminal device can be regarded as having the same source and target PDCP configurations associated with one PDCP. Or, the terminal device can apply the target PDCP configuration to the source PDCP configuration.

[0693] In addition, in the case where the source DRB (or SRB) and the target DRB with the same DRB identifier are associated with one PDCP entity, the security keys of the source and the target are different (such as KUPenc, KUPint, KRRCenc, and / or KRRCint, etc.), so multiple security keys are managed in one PDCP entity.

[0694] Another example of the MBB-HO operation is described. Here, an example of using an RRC connection reconfiguration message including conditional handover configuration in LTE is shown.

[0695] For example, the RRC message transmitted by the base station device may include a conditional handover information element. The conditional handover information element may include a list including one or more information elements (conditional handover settings) that include the information included in the mobilityControlInfo information element. In addition, the conditional handover information element may include an information element (conditional handover condition) indicating a condition for applying the conditional handover setting to each conditional handover setting or a part or all of the conditional handover settings.

[0696] The conditional handover settings may include part or all of the information included in the radio resource settings common to the cell (radioBearerConfigCommon) and the radio resource settings specific to the terminal device (radioBearerConfigDedicated). In addition, the conditional handover settings may also include information indicating that it is MBB-HO (for example, MakeBeforeBreak-r16). In addition, the conditional handover condition may include threshold information for using a reference signal to determine whether the condition is satisfied. In addition, the conditional handover condition may also include information indicating immediate application of the conditional handover settings. For example, when the conditional handover condition indicates information indicating immediate application of the conditional handover settings and information indicating that it is MBB-HO is added to the conditional handover settings, the process LA is performed based on the information included in the conditional handover settings, thereby enabling MBB-HO. Of course, when the condition is satisfied even when the conditional handover condition is other conditions, the process LA is performed based on the information included in the conditional handover settings, thereby enabling conditional MBB-HO.

[0697] In the MBB-HO (MakeBeforeBreak-r16) of LTE, the terminal device may adopt a configuration of a single PDCP common to the source and the target.

[0698] For example, when the core network is 5GC, in the source configuration, through RLC bearer configuration, the logical channel, DRB (or SRB), and RLC bearer are associated. Then, through drb-ToAddMod, the DRB, PDCP entity, and PDU session are associated. Similarly, in the target configuration, through RLC bearer configuration, the logical channel, DRB (or SRB), and RLC bearer are associated. Then, through drb-ToAddMod, the DRB (or SRB), PDCP entity, and PDU session are associated. In this case, for example, the logical channel, DRB (or SRB), and / or RLC bearer associated with the same DRB identifier (or SRB identifier) in the source and target configurations can be associated with one PDCP. In addition, for example, the logical channel, DRB (or SRB), and / or RLC bearer associated with the same PDU session in the source and target configurations can be associated with one PDCP.

[0699] For example, when the core network is 5GC, in the source configuration, through RLC bearer configuration, the logical channel, DRB (or SRB), and RLC bearer are associated. Then, through drb-ToAddMod, the DRB, PDCP entity, and PDU session are associated. Similarly, in the target configuration, through RLC bearer configuration, the logical channel, DRB (or SRB), and RLC bearer are associated. Then, through drb-ToAddMod, the DRB (or SRB), PDCP entity, and PDU session are associated. In this case, for example, the logical channel, DRB (or SRB), and / or RLC bearer associated with the same DRB identifier (or SRB identifier) in the source and target configurations can be associated with one SDAP.

[0700] In addition, for example, when the core network is EPC, in the source configuration, the DRB (or SRB), PDCP entity, logical channel, RLC entity (and / or RLC bearer), and EPS bearer are associated. Similarly, in the target configuration, the DRB (or SRB), PDCP entity, logical channel, RLC entity (and / or RLC bearer), and EPS bearer are associated. In this case, for example, the logical channel, RLC entity (and / or RLC bearer) associated with the same DRB identifier (or SRB identifier) in the source and target configurations can be associated with one PDCP entity. In addition, for example, the logical channel, RLC entity (and / or RLC bearer), DRB (or SRB) associated with the same EPS bearer identifier in the source and target configurations can be associated with one PDCP.

[0701] In the above case, the PDCP settings of the source and target associated with a PDCP in the terminal device can be regarded as the same. Alternatively, the terminal device can apply the PDCP settings of the target to the PDCP settings of the source.

[0702] In addition, in the case where the DRB of the source and the DRB (or SRB) of the target with the same DRB identifier are associated with a PDCP entity, the security keys of the source and the target (such as KUPenc) are different, so multiple security keys are managed in one PDCP entity.

[0703] It should be noted that MakeBeforeBreak-r16 may include information indicating which layer of the target is generated or not generated until the connection to the target is completed.

[0704] It should be noted that in the case of NR, the processing in (Processing E) may include the following processing below (E2-1). For example, as Figure 22 shown, the processing (E2-1) may be executed between the processing (E-1) and the processing (E-2), but it is not limited thereto. In addition, in the case of LTE, the processing in (Processing LF) may include the following processing below (E2-1). For example, the processing (E2-1) may be executed before the processing (LF-1), but it is not limited thereto.

[0705] (E2-1) If it is MBB-HO and the MAC entity for the target (also called the secondary MAC entity) exists as part of the settings of the current terminal device, then

[0706] (E2-1-1) Generate the secondary MAC entity.

[0707] Thereby, in the processing based on the MAC layer settings, the MAC entity can be appropriately generated.

[0708] In addition, in the case of NR, the processing within the scope of the processing (B-9) of the (Processing B) may be, for example, the processing (B2-9) as Figure 23 shown. In addition, in the case of MBB-HO, the settings for "this cell group" in the processing after the processing (B-9) in the (Processing B) can be applied to the target.

[0709] (B2-9) If the synchronization reconfiguration includes information indicating that it is MBB-HO,

[0710] (B2-9-1) If the MAC entity for the target (also called the secondary MAC entity) exists as part of the settings of the current terminal device, then

[0711] (B2-9-1-1) Do not reset the MAC entity (also known as the primary MAC entity) of the existing cell group.

[0712] (B2-9-1-2) Generate a secondary MAC entity.

[0713] (B2-9-2) Apply the established (default) MAC cell group settings to the secondary MAC entity. Alternatively, apply the same settings as the primary MAC entity to the secondary MAC entity.

[0714] (B2-9-3) Reset the secondary MAC entity.

[0715] (B2-9-4) If settings are made, consider the SCell of this cell group to be in the deactivated state.

[0716] (B2-9-5) Use the value of newUE-Identity as the C-RNTI of this cell group.

[0717] In addition, in the case of LTE, the processing within the range of the processing (LA-6) to the processing (LA-7) of the said (processing LA) can be, for example, the processing (LA2-6) and the processing (LA2-7) as Figure 24 shown.

[0718] (LA2-6) If makeBeforeBreak-r16 is set, then

[0719] (LA2-6-1)Copy the settings of the current terminal device (source settings) as the target settings, and unless otherwise specifically stated, the following subsequent reconfiguration processes can be performed on the copied target settings. For example, in the case of MBB-HO, the "settings of the current terminal device" for each process can be regarded as the "target settings of the current terminal device". In addition, for example, the settings to be copied may include (1) bearer settings (such as SRB settings, DRB settings, etc.), (2) cell group settings (such as SpCell settings, SCell settings, RLC entity settings, MAC entity settings, PHY settings, etc.), (3) internal variables (measurement settings (VarMeasConfig), measurement results (VarMeasReportList), timers, counters, etc.), and (4) security-related settings (such as each key), either partially or in full. In addition, the SRB settings may not be included in the bearer settings to be copied. That is, for DRB, both the source settings and the target settings can be managed. For SRB, instead of copying the settings, the settings can be switched from the source settings to the target settings. In addition, the information that can determine whether to copy the SRB settings may be included in the RRC connection reconfiguration message including mobilityControlInfo. For example, the above information may be included in MakeBeforeBreak-r16. In addition, the above copy may be accompanied by the generation of entities at each layer (such as RLC entities, MAC entities).

[0720] (LA2-6-2)If the MAC entity for the target (also called the secondary MAC entity) exists as part of the settings of the current terminal device, then

[0721] (LA2-6-2-1)Do not reset the existing MAC entity of this cell group (also called the primary MAC entity).

[0722] (LA2-6-2-2)Generate a secondary MAC entity.

[0723] (LA2-6-3)If necessary, reset the secondary MAC entity.

[0724] (LA2-7)Otherwise

[0725] (LA2-7-1)If the settings are made, reset the MAC of MCG and the MAC of SCG.

[0726] Thereby, even when the MAC cell group settings are not included in the NR RRC reconfiguration message, the generation of MAC entities can be appropriately performed. In addition, when the MAC primary settings are not included in the EUTRA RRC connection reconfiguration message, the generation of MAC entities can be appropriately performed.

[0727] In addition, in the aforementioned (Process I), (Process J), or other processes, when the terminal device receives a message for setting a release source, it can release the current primary MAC entity and regard the current secondary MAC entity as the primary MAC entity. In addition, when the terminal device receives a message for setting a release source, it can reset the current primary MAC entity, not regard the current primary MAC entity as the primary MAC entity, but regard the current secondary MAC entity as the primary MAC entity.

[0728] Thus, the management of the MAC entity can be appropriately performed.

[0729] It should be noted that in each of the above processes, handover (also referred to as MBB-HO) is performed when makeBeforeBreak-r16 is included in the setting of the primary cell group, and secondary cell group change (also referred to as MBB-SCG Change) is performed when makeBeforeBreak-r16 is included in the setting of the secondary cell group.

[0730] In addition, the terminal device can notify the base station device of some or all of the following information: (1) information indicating whether it supports performing MBB-HO or MBB-SCG Change for maintaining communication using two or more cell groups (e.g., Dual Connectivity, MultiConnectivity); (2) information indicating whether it supports performing MBB-HO for maintaining communication using two or more cell groups (e.g., Dual Connectivity); (3) information indicating whether it supports performing MBB-SCG Change for maintaining communication using two or more cell groups (e.g., Dual Connectivity); (4) information indicating whether it supports performing both MBB-HO and MBB-SCG Change for maintaining Dual Connectivity. For example, the information can be included in a message (e.g., UECapabilityInformation) in which the terminal device notifies the base station device 3 of its radio access capability (Capability). In addition, the information can be notified as information independent of the band combination supported by the terminal device. In addition, the information can also be notified as information for each band combination supported by the terminal device. In addition, the information can also not be notified to the base station device.

[0731] In addition, the terminal device may release one or more cell groups other than the MCG to perform MBB-HO. The terminal device may perform the MBB-HO without supporting the execution of MBB-HO that maintains communication using two or more cell groups. In addition, the terminal device may also release one or more cell groups other than the MCG to perform MBB-SCG Change. The terminal device may also perform the MBB-SCG Change without supporting the execution of MBB-SCG Change that maintains communication using two or more cell groups. In addition, the terminal device may perform a change of a normal secondary cell group (SCG Change) that is not MBB-SCG Change. The terminal device may perform the change of the secondary cell group without supporting the execution of MBB-SCG Change that maintains communication using two or more cell groups. SCG Change may be renamed as synchronous SCG reconfiguration (SCGreconfiguration with sync). In addition, handover (HO) may be renamed as synchronous MCG reconfiguration (MCGreconfiguration with sync).

[0732] Figure 10 is an example of the ASN.1 description of the RRC connection reconfiguration message of EUTRA in Figure 4 . In addition, Figure 11 is an example of the ASN.1 description of the RRC connection reconfiguration message of EUTRA in Figure 4 . In addition, Figure 12 is an example of the ASN.1 description of the RRC reconfiguration message of NR in Figure 4 . In addition, Figure 13 is an example of the ASN.1 description of the RRC reconfiguration message of NR in Figure 4 .

[0733] In Figure 10 and Figure 11 , the information element indicated by mobilityControlInfo is an information element including parameters related to network-controlled mobility to EUTRA. Part or all of the following information (A) to (H) may be included in the information element indicated by mobilityControlInfo.

[0734] (A) Target physical cell identifier

[0735] (B) t304 of the information indicating the time from the start to the expiration of timer T304

[0736] (C) newUE-Identity indicating the new identifier (C-RNTI) of UE122

[0737] (D) Radio resource configuration

[0738] (E) Configuration of dedicated random access channel

[0739] (F) makeBeforeBreak-r14 as a parameter for configuring existing (Release14) make-before-break handover

[0740] (G) rach-Skip-r14 as a parameter for configuring RACH-less handover

[0741] (H) makeBeforeBreak-r16 as a parameter for configuring make-before-break handover in this embodiment

[0742] Figure 10 Indicates an example where makeBeforeBreak-r16 is an enumerated type, Figure 11 Indicates an example where makeBeforeBreak-r16 has an information element MakeBeforeBreak-r16 as its value, and the information element MakeBeforeBreak-r16 has multiple fields.

[0743] In Figure 12 and Figure 13 , the information element indicated by the synchronization reconfiguration is, for example, an information element including parameters related to the handover of the PCell, the addition and change of the PSCell. The information element indicated by the synchronization reconfiguration may include some or all of the following information (A) to (F).

[0744] (A) Configuration of SpCell

[0745] (B) t304, information indicating the time from the start to the expiration of timer T304

[0746] (C) newUE-Identity indicating the new identifier (RNTI) of UE122

[0747] (D) Configuration of dedicated random access channel

[0748] (E) makeBeforeBreak-r16 as a parameter for configuring make-before-break handover in this embodiment

[0749] (F) rach-Skip-r16 as a parameter for configuring RACH-less handover

[0750] Figure 12Indicates an example where makeBeforeBreak-r16 is an enumerated type, Figure 13 Indicates an example where makeBeforeBreak-r16 has the information element MakeBeforeBreak-r16 as its value, and the information element MakeBeforeBreak-r16 has multiple fields.

[0751] In addition, Figures 10 - 13 Some or all of the fields shown may be optional. That is, Figures 10 - 13 The fields shown may be included in the message according to conditions.

[0752] It should be noted that it is possible to set whether to apply make-before-break handover (MBB-HO) to each radio bearer from eNB102 or gNB108. When setting whether to apply make-before-break handover to each radio bearer, the parameters related to make-before-break handover can be set under (lower layer) the radio bearer setting (the information element represented by SRB-ToAddMod and / or the information element represented by DRB-ToAddMod), or can exist under the information element represented by PDCP-Config. In addition, when setting whether to apply make-before-break handover to each radio bearer, instead of making the parameters related to make-before-break handover exist under the radio bearer setting or under the information element represented by PDCP-Config, the information of the radio bearer to which make-before-break handover is applied can exist above (upper layer) the radio bearer setting.

[0753] Figure 20 Examples of ASN.1 for parameters (information elements or fields) for setting whether to apply make-before-break handover (MBB-HO) to radio bearers to be established or set, which represent various embodiments of the present invention, are shown. In Figure 20In the example, an example is shown where there is a parameter under PDCP-Config for setting whether to apply make-before-break handover to the radio bearer to be established or configured. However, if it is under radio bearer configuration, it can exist anywhere. It should be noted that the above "whether to apply make-before-break handover to the radio bearer to be established or configured" can be renamed as "whether to perform make-before-break handover on the radio bearer to be established or configured", "whether it is a radio bearer applying make-before-break", and other similar expressions. In addition, the above "whether to apply make-before-break handover to the radio bearer to be established or configured" can also be renamed as "whether to apply make-before-break handover to the PDCP entity" or "whether the PDCP entity performs make-before-break handover" or "the PDCP entity has a second setting and a third setting", etc. The above second setting can be the source (handover source) setting of the handover. In addition, the above third setting can be the target (handover destination) setting of the handover. In addition, the above second setting can be the primary setting. In addition, the above third setting can be the secondary setting. In addition, if the expression of performing make-before-break handover is achieved by setting both the source setting and the target setting and / or both the primary setting and the secondary setting for a PDCP entity, it can be renamed as other expressions.

[0754] In Figure 20 the example, the field represented by mbb-drb is used as the parameter for "whether to apply make-before-break handover to the radio bearer to be established or configured" for illustration, but it can also be a field and / or information element with other names. Figure 20 (A) of Figure 20 shows an example where mbb-drb is an enumerated type, Figure 20 (B) of Figure 20 shows an example where mbb-drb has an MBB-DRB with information elements as its value, and the MBB-DRB with information elements has one or more fields. In

[0755] It should be noted that Figure 20 the field represented by mbb-drb shown in Figures 10 to 13Optionally exists when the setting shown in the example has parameters equivalent to those of makeBeforeBreak-r16. In Figures 10 to 13 When the example shown does not have parameters equivalent to those of makeBeforeBreak-r16, the field represented by mbb-drb may not exist.

[0756] Figure 21 An example of ASN.1 is shown in which information on radio bearers that enable the application to switch from connect-before-disconnect exists above the radio bearer setting. As Figure 21 shown, as Figure 11 and / or Figure 13 One of the parameters of the information element of MakeBeforeBreak-r16 (for example, Figure 11 and / or Figure 13 parameterA or parameterB shown in Figure 21 ), information on radio bearers that enable the application to switch from connect-before-disconnect may exist. In the example of Figure 21 , as a parameter of "information on radio bearers that enable the application to switch from connect-before-disconnect", a field represented by mbb-drb and mbb-drbList (a list of mbb-drb) is used for explanation, but it can also be a field and / or information element with other names. As Figure 21 shown, the above-mentioned information on radio bearers that enable the application to switch from connect-before-disconnect can be part or all of the radio bearer identifier of the above-mentioned radio bearers that enable the application to switch from connect-before-disconnect (the field represented by drb-Identity), the identifier of the cell group of the handover destination (the field with the name targetCellGroupId), the logical channel identifier associated with the PDCP entity at the handover destination (the field with the name targetLogicalChannelIdentity), and other parameters (not shown). In addition, in the example of Figure 21 , when the parameter of "information on radio bearers that enable the application to switch from connect-before-disconnect" does not exist, the connect-before-disconnect switch can be applied to all radio bearers or all data radio bearers. In addition, as the "information on radio bearers that enable the application to switch from connect-before-disconnect" of Figure 21 , only information on data radio bearers (DRB) is shown, but it can also include information on signaling radio bearers (SRB).

[0757] Figure 5 is a block diagram showing the configuration of the terminal device (UE122) according to each embodiment of the present invention. It should be noted that, to avoid cumbersome description, only the main components closely related to one aspect of the present invention are shown in Figure 5 .

[0758] Figure 5The UE 122 shown in [figure] is composed of a receiving unit 500 that receives RRC messages and the like from a base station device, a processing unit 502 that processes according to setting information of any one or all of various information elements (IE: Information Element), various fields, and various conditions included in the received message, and a transmitting unit 504 that transmits RRC messages and the like to the base station device. The above-mentioned base station device sometimes refers to the eNB 102 and sometimes refers to the gNB 108. In addition, the processing unit 502 may include some or all of the functions of various layers (for example, the physical layer, the MAC layer, the RLC layer, the PDCP layer, the RRC layer, and the NAS layer). That is, the processing unit 502 may include some or all of a physical layer processing unit, a MAC layer processing unit, an RLC layer processing unit, a PDCP layer processing unit, an RRC layer processing unit, and a NAS layer processing unit.

[0759] Figure 6 is a block diagram showing the configuration of the base station device according to each embodiment of the present invention. It should be noted that, to avoid cumbersome description, in Figure 6 only the main components closely related to one aspect of the present invention are shown. The above-mentioned base station device sometimes refers to the eNB 102 and sometimes refers to the gNB 108.

[0760] Figure 6 The base station device shown in [figure] is configured to include: a transmitting unit 600 that transmits RRC messages and the like to the UE 122; a processing unit 602 that creates an RRC message including setting information of any one or all of various information elements (IE: Information Element), various fields, and various conditions, and by transmitting it to the UE 122, causes the processing unit 502 of the UE 122 to perform processing; and a receiving unit 604 that receives RRC messages and the like from the UE 122. In addition, the processing unit 602 may include some or all of the functions of various layers (for example, the physical layer, the MAC layer, the RLC layer, the PDCP layer, the RRC layer, and the NAS layer). That is, the processing unit 602 may include some or all of a physical layer processing unit, a MAC layer processing unit, an RLC layer processing unit, a PDCP layer processing unit, an RRC layer processing unit, and a NAS layer processing unit.

[0761] Figure 25 is an example of the processing method of the UE 122 according to each embodiment of the present invention. The processing unit 602 of the base station device (eNB 102 and / or gNB 108) generates a message related to the reconfiguration of the RRC connection for causing the UE 122 to perform processing, and transmits it to the UE 122 (not shown) by the transmitting unit 600. The receiving unit 500 of the UE 122 receives the message related to the reconfiguration of the RRC connection transmitted by the base station device (step S2500).

[0762] The processing unit 502 of UE122 confirms whether the message related to the reconfiguration of the above-mentioned RRC connection includes the first information. If the above-mentioned first information is not included, it can be determined that it is not a pre-connected and post-disconnected handover. If the above-mentioned first information is included, it can be determined that it is a pre-connected and post-disconnected handover. In addition, if the above-mentioned first information is included, it can be determined that the pre-connected and post-disconnected handover is applied to a part or all of the radio bearers configured in the current UE122, or the pre-connected and post-disconnected handover can be applied. In addition, when the above-mentioned first information is included in the message related to the reconfiguration of the above-mentioned RRC connection, the processing unit 502 of UE122 can generate a cell group and / or a MAC entity for the target of the pre-connected and post-disconnected handover (step S2502).

[0763] The processing unit 502 of UE122 can also confirm whether the message related to the reconfiguration of the above-mentioned RRC connection includes the second information based on the situation where the above-mentioned first information is included. If the above-mentioned second information is not included, it can be determined that the pre-connected and post-disconnected handover is not applied to all the radio bearers configured in the current UE122. If the above-mentioned second information is included, based on the above-mentioned second information, it can be determined which radio bearers among the radio bearers configured in the current UE122 apply the pre-connected and post-disconnected handover and / or which radio bearers do not apply the pre-connected and post-disconnected handover (step S2504).

[0764] It should be noted that the above-mentioned first information in step S2502 and / or step S2504 can be information indicating the above-mentioned MBB-HO. In addition, the above-mentioned first information, as Figure 10 or Figure 11 shown, can be included in the mobilityControlInfo information element, as Figure 12 shown Figure 13 , and can also be included in the reconfigurationWithSync information element.

[0765] The processing unit 502 of UE122 can change or reconfigure the cell group associated with the RLC bearer of the radio bearer to which the above-mentioned pre-connected and post-disconnected handover is not applied from the first cell group to the second cell group (step S2506).

[0766] In addition, the processing unit 502 of UE122 can establish a second RLC bearer for the radio bearer to which the above-mentioned pre-connected and post-disconnected handover is applied, and establish an association with the PDCP entity of the radio bearer to which the above-mentioned pre-connected and post-disconnected handover is applied. In addition, at this time, the above-mentioned second RLC bearer can be associated with the above-mentioned second cell group (step S2508).

[0767] It should be noted that the above second information in step S2504 and / or step S2506 and / or step S2508 may be information indicating whether to perform a make-before-break handover for the radio bearer application to be established or set (shown in Figure 21 and / or Figure 22 ).

[0768] In addition, in step S2506 and / or step S2508, the second cell group may be a cell group generated based on the situation where the above first information is included in the message related to the reconfiguration of the above RRC connection in step S2502.

[0769] In addition, in step S2506, changing or reconfiguring the cell group associated with the RLC bearer of the radio bearer for which the above make-before-break handover is not applied from the above first cell group to the above second cell group may be a case of performing part or all of the actions including the following (A) and (B) on the RLC entity of the radio bearer for which the above make-before-break handover is not applied and / or the logical channel of the radio bearer for which the above make-before-break handover is not applied.

[0770] (A) Reconfiguring the above RLC entity of the first cell group to the above RLC entity of the second cell group.

[0771] (B) Reconfiguring the above logical channel of the first cell group to the above logical channel of the second cell group.

[0772] It should be noted that the above logical channel may be a DTCH logical channel. In addition, the above first cell group may be the cell group associated with the radio bearer for which the above make-before-break handover is not applied before performing the make-before-break handover.

[0773] In step S2508, establishing an association between the above second RLC bearer and the above second cell group may be a case of performing part or all of the actions including the following (C) and (D).

[0774] (C) Setting or reconfiguring the RLC entity of the above second RLC bearer to the RLC entity of the above second cell group.

[0775] (D) Setting or reconfiguring the logical channel of the above second RLC bearer to the logical channel of the second cell group.

[0776] It should be noted that the above logical channel may be a DTCH logical channel.

[0777] In addition, in step S2506 and / or step S2508, both the first cell group and the second cell group may be master cell groups (MCGs). In addition, in step S2506 and / or step S2508, the first cell group and the second cell group may be referred to as the first MAC entity and the second MAC entity, respectively. The above-mentioned second MAC entity may be the MAC entity for the target of the make-before-break handover generated in the above-mentioned step S2502. In addition, the above-mentioned first cell group may be the source MCG during the make-before-break handover and / or the MCG in the case where no make-before-break handover is performed. In addition, the above-mentioned second cell group may be the target MCG during the make-before-break handover. In addition, the above-mentioned first MAC entity may be the source MAC entity during the make-before-break handover and / or the MAC entity in the case where no make-before-break handover is performed. In addition, the above-mentioned second MAC entity may be the target MAC entity during the make-before-break handover.

[0778] In addition, in step S2506, before changing the cell group associated with the RLC bearer of the radio bearer to which the make-before-break handover is not applied from the first cell group to the second cell group, the radio bearer to which the make-before-break handover is not applied may be copied. The copying of the above-mentioned radio bearer may be a case of preparing a radio bearer having the same setting as the setting of the above-mentioned radio bearer. In addition, the copying of the above-mentioned radio bearer may be a case of preparing a radio bearer having the same setting as the setting of the above-mentioned radio bearer and having the same data as the data being processed in the above-mentioned radio bearer. In addition, the data being processed in the above-mentioned radio bearer may include PDUs and / or SDUs saved by each layer, buffers of each layer, variables saved by each layer, values of timers, etc. In addition, either the radio bearer to which the make-before-break handover is not applied or the copied radio bearer may be stopped. In addition, the process of "changing the cell group associated with the RLC bearer of the radio bearer to which the make-before-break handover is not applied from the first cell group to the second cell group" in step S2506 may be performed on the bearer that is not stopped. In addition, the stopping of the above-mentioned radio bearer may include the stopping of uplink transmission and may also include the stopping of downlink reception.

[0779] In addition, in the above-mentioned step S2502, instead of performing the process of the above-mentioned step S2504, it may be determined that the make-before-break handover is applied to all radio bearers based on the above-mentioned first information included in the message related to the reconfiguration of the above-mentioned RRC connection. In this case, the process of the above-mentioned step S2506 may also not be performed.

[0780] Figure 26This is another example of the processing method of the UE 122 according to various embodiments of the present invention. The processing unit 502 of the UE 122 that attempts to switch from a handover source to a handover destination (target) detects that the first timer has expired (step S2600). It should be noted that the above-mentioned first timer can be started when receiving a message related to the reconfiguration of the RRC connection including a parameter indicating handover (an information element named MobilityControlInfo described in Non-Patent Document 4 or an information element named ReconfigurationWithSync described in Non-Patent Document 10) or when moving to a cell from a different RAT (CellChangeOrder described in Non-Patent Document 4), and stops when the handover is successful or when CellChangeOrder is successful or when the random access to the corresponding SpCell is successful. In addition, the above-mentioned first timer can be the timer T304 described in Non-Patent Document 4 or Non-Patent Document 10. It should be noted that the above-mentioned handover can be a process performed when receiving a message related to the reconfiguration of the RRC connection including a parameter indicating handover (an information element named MobilityControlInfo described in Non-Patent Document 4 or an information element named ReconfigurationWithSync described in Non-Patent Document 10). In addition, the above-mentioned handover can also be a DAPS handover.

[0781] In step S2600, the processing unit 502 of the UE122 that has detected the expiration of the first timer can then determine whether to perform a first setting on the UE122. In the case of performing the first setting on the UE122, a part or all of the settings for the handover destination (target) can be released based on the performance of the first setting (step S2602). It should be noted that the above first setting can be a setting related to DAPS handover, or can be a setting related to the radio bearer to which DAPS handover is applied. In addition, the case of performing the above first setting can also be referred to as the case of setting DAPS handover for any radio bearer, or can also be referred to as the case of setting DAPS handover for at least one radio bearer, or can also be referred to as other similar expressions. In addition, the release of a part or all of the settings for the handover destination (target) can be a case where the settings including a part or all of the RLC entity and the logical channel for the radio bearer to which DAPS handover is applied are released for the handover destination (target). In addition, the release of the settings for the handover destination (target) can be a case where, for the radio bearer for which DAPS handover is not applied, a part or all of the correspondence rules between the PDCP entity and the bearer identifier, the RLC entity and the logical channel, and the QoS flow and the radio bearer in the SDAP for the handover destination (target) are released. In addition, the MAC entity of the handover destination (target) can also be reset when the above settings for the handover destination (target) are released.

[0782] In addition, in step S2602, the processing unit 502 of the UE122 can determine whether to perform a first setting on the UE122. In the case of performing the first setting on the UE122, it can also be determined whether a radio link failure has been detected in the primary cell of the handover source. In the case where no radio link failure has been detected in the primary cell of the handover source, a part or all of the settings for the handover destination (target) can be released based on the above case of performing the first setting on the UE122 and the case where no radio link failure has been detected in the primary cell of the handover source. It should be noted that the above primary cell can be a PCell (Primary Cell), or can also be an SpCell (Special Cell).

[0783] In addition, in step S2600, the processing unit 502 of the UE122 that has detected the expiration of the first timer may determine whether to perform a first setting on the UE122. In the case of performing the first setting on the UE122, based on the situation of performing the first setting, the security key set for the handover source is updated (step S2604). It should be noted that the above-mentioned first setting may be a setting related to DAPS handover, or may be a setting related to the radio bearer to which DAPS handover is applied. In addition, the situation of performing the above-mentioned first setting may also be referred to as the situation of setting DAPS handover for any radio bearer, or may also be referred to as the situation of setting DAPS handover for at least one radio bearer, or may also be referred to as other similar expressions. In addition, setting the security key for the handover source mentioned above may also be referred to as the security key set for the handover source. In addition, the update of the security key mentioned above may be a process including a part or all of the following (A) to (B).

[0784] (A) Generate a base station key based on the current base station key or NH (Next Hop) information.

[0785] (B) Generate a part or all of the confidentiality key for SRB, the integrity key for SRB, the confidentiality key for DRB, and the integrity key for DRB.

[0786] In addition, in step S2604, after the update of the security key, before the update of the security key, or without the update of the security key, a process including a part or all of the following (C) to (F) may be performed.

[0787] (C) For a part or all of the SRBs, set the lower layer so as to perform integrity protection processing using the above-mentioned integrity key for SRB or the set integrity key for SRB and the set integrity algorithm.

[0788] (D) For a part or all of the DRBs, set the lower layer so as to perform integrity protection processing using the above-mentioned integrity key for DRB or the set integrity key for DRB and the set integrity algorithm.

[0789] (E) For a part or all of the SRBs, set the lower layer so as to perform encryption processing using the above-mentioned confidentiality key for SRB or the set confidentiality key for SRB and the set confidentiality algorithm.

[0790] (F) For a part or all of the DRBs, set the lower layer so as to perform encryption processing using the above-mentioned confidentiality key for DRB or the set confidentiality key for DRB and the set confidentiality algorithm.

[0791] It should be noted that in step S2604, the base station key can be KeNB described in non-patent document 21 or KgNB described in non-patent document 21. In addition, in step S2604, the integrity keys for SRB and DRB can be KRRCint and KUPint described in non-patent document 21 and / or non-patent document 22 respectively. In addition, in step S2604, the confidentiality keys for SRB and DRB can be KRRCenc and KUPenc described in non-patent document 21 and / or non-patent document 22 respectively. In addition, in step S2604, the above-mentioned NH (Next Hop) can be NH (Next Hop) described in non-patent document 21 and / or non-patent document 22. In addition, in step S2604, the lower layer can be the PDCP layer or the PDCP entity.

[0792] In addition, the process of (C) in step S2604 can also be renamed as a process of setting a lower layer for all SRBs except SRB1 to perform integrity protection using the above-mentioned integrity key for SRB or the set integrity key for SRB and the set integrity algorithm. In addition, the process of (E) in step S2604 can also be renamed as a process of setting a lower layer for all SRBs except SRB1 to perform encryption using the above-mentioned confidentiality key for SRB or the set confidentiality key for SRB and the set confidentiality algorithm. In addition, in step S2600, part or all of the processes in step S2604 can be performed after UE122 detects that the first timer has expired and before sending the first RRC message to the source base station device of the handover. In addition, in step S2600, part or all of the processes in step S2604 can be performed after UE122 detects that the first timer has expired and after sending the first RRC message to the source base station device of the handover. The above-mentioned first RRC message can be an RRC message for notifying that the handover to the target DAPS has failed. In addition, after sending the first RRC message to the source base station device of the handover, a lower layer can be set for SRB1 or part or all of the radio bearers to perform integrity protection using the above-mentioned integrity key for SRB or the set integrity key for SRB and the set integrity algorithm. In addition, after sending the first RRC message to the source base station device of the handover, a lower layer can be set for SRB1 or part or all of the radio bearers to perform encryption using the above-mentioned confidentiality key for SRB or the set confidentiality key for SRB and the set confidentiality algorithm. In addition, in step S2604, part or all of the radio bearers can be suspended before or after updating the security key. In addition, part or all of the suspended radio bearers can be resumed when or before sending the above-mentioned first RRC message to the source base station device of the handover after UE122 detects that the first timer has expired. The above-mentioned resumed radio bearers can include SRB1 or all SRBs.

[0793] In addition, in step S2600, part or all of the processing in step S2604 can be performed after UE122 detects the expiration of the first timer, when receiving the first RRC message from the base station device of the handover source or after receiving the first RRC message. In addition, in step S2600, part or all of the processing in step S2604 can be performed after UE122 detects the expiration of the first timer, based on a parameter indicating the update of the security key included in the first RRC message received from the base station device of the handover source for the first time. The first RRC message received from the base station device of the handover source as described above can be a message related to the reconfiguration of the RRC connection, a message related to the resume of the RRC connection, or other RRC messages. The parameter indicating the update of the security key as described above can be included in the above RRC message based on the failure of the DAPS handover. In addition, the parameter indicating the update of the security key as described above can be a parameter (field) represented by the name securityConfigHO described in Non-Patent Document 4, or a parameter (field) represented by the name masterKeyUpdate described in Non-Patent Document 10.

[0794] In addition, in step S2604, the MAC entity of the handover source can be reset. The processing of resetting the MAC entity of the handover source as described above can be performed before or after the update processing of the security key of the handover source, or can be performed after UE122 detects the expiration of the first timer, before sending the first RRC message to the base station device of the handover source, or after sending the first RRC message. In addition, the processing of resetting the MAC entity of the handover party as described above can also be performed after UE122 detects the expiration of the first timer, when receiving the first RRC message from the base station device of the handover source or after receiving the first RRC message. In addition, in step S2604, part or all of the PDCP entities of the radio bearers can be re-established before or after the update processing of the security key of the handover source.

[0795] In addition, in step S2604, the processing unit 502 of the UE 122 may determine whether to perform a first setting on the UE 122. In the case of performing the first setting on the UE 122, it may also be determined whether a radio link failure is detected in the primary cell of the handover source. In the case where a radio link failure is not detected in the primary cell of the handover source, the update of the security key set for the handover source and the above processing may be performed based on the first setting being performed on the UE 122 and the radio link failure not being detected in the primary cell of the handover source. It should be noted that the above primary cell may be a PCell (Primary Cell) or an SpCell (Special Cell).

[0796] In addition, in step S2604, based on the first setting being performed on the UE 122 and / or the radio link failure not being detected in the primary cell of the handover source, a process of reverting the setting used by the handover source for some or all radio bearers may be performed. The above process of reverting the setting used by the handover source may be performed for radio bearers for which DAPS handover is not applied. In addition, the above process of reverting the setting used by the handover source for some or all radio bearers in step S2604 may be performed before the security key update process, after the security key update process, after the UE 122 detects the expiration of the first timer, and before sending the above first RRC message to the base station device of the handover source, or after sending the above first RRC message.

[0797] It should be noted that in step S2604, the security key update may also be performed without being based on the first setting being performed on the UE 122 and / or the radio link failure not being detected in the primary cell of the handover source.

[0798] It should be noted that in step S2604, the security key update may not be performed either.

[0799] The receiving unit 500 of the UE 122 may receive a message related to the re - setting of the RRC connection from the base station device. The processing unit 502 of the UE 122 may establish or re - set a radio bearer based on the above message related to the re - setting of the RRC connection (step S2606). It should be noted that some or all of the processing in step S2604 above may be performed when establishing or re - setting a radio bearer in step S2606.

[0800] In addition, in step S2604 and / or step S2606, for some or all of the radio bearers, part or all of the data stored in the buffer may be discarded. The data stored in the buffer described above may be part or all of PDCP SDU, PDCP PDU, RLC SDU, RLC PDU, MAC SDU, and MAC PDU. In addition, the data stored in the buffer described above may include the data stored in the retransmission buffer. The process of discarding part or all of the data stored in the buffer may be performed for the radio bearers for which DAPS handover is not applied.

[0801] It should be noted that part or all of the term "source" in the handover from step S2600 to step S2606 may be renamed as the PCell of the handover party (source PCell), or may be renamed as the cell group of the handover party (source cell group). In addition, part or all of the term "destination (target)" in the handover from step S2600 to step S2606 may be renamed as the PCell of the handover destination (target PCell), or may be renamed as the cell group of the handover destination (target cell group).

[0802] In this way, in the embodiment of the present invention, efficient communication can be performed during the handover of UE122.

[0803] Each of the radio bearers in the above description may be a DRB, or may be an SRB, or may be a DRB and an SRB.

[0804] In addition, in the above description, the radio bearer to which DAPS handover is applied may be a DRB to which DAPS handover is applied. In addition, the radio bearer for which DAPS handover is not applied may be a DRB for which DAPS handover is not applied.

[0805] In addition, in the above description, expressions such as "associate", "establish correspondence", and "establish association" may be replaced with each other.

[0806] In addition, in the examples of the respective processes or the examples of the respective process flows in the above description, part or all of the steps may not be executed. In addition, in the examples of the respective processes or the examples of the respective process flows in the above description, the order of the steps may be different. In addition, in the examples of the respective processes or the examples of the respective process flows in the above description, part or all of the processing in each step may not be executed. In addition, in the examples of the respective processes or the examples of the respective process flows in the above description, the order of the processing in each step may be different.

[0807] In the above description, "in the case of MBB-HO" and / or "being MBB-HO" may be the case where, when performing an RRC connection reconfiguration including MobilityControlInfo in LTE or an RRC reconfiguration including a synchronization reconfiguration in NR, transmission and / or reception in a target cell is performed while continuing transmission and / or reception of user data in a source cell, and may also be expressed by other names indicating equivalent actions. Further, "in the case of MBB-HO" and / or "being MBB-HO" may be the case where, in LTE or NR, a specific information element (e.g., Figures 10 - 13 , Figure 21 the MakeBeforeBreak-r16 information element shown in and / or Figures 20 - 22 the mbb-drb shown in) is included in the RRC reconfiguration message. Further, "in the case of MBB-HO" and / or "being MBB-HO" may also be the case where the time (interruption time) during which data communication cannot be performed between the terminal device and the base station device is set to zero milliseconds (0 msec) or made close to zero milliseconds, and may also be expressed by other names indicating it.

[0808] Further, in the above description, "settings related to MBB-HO" may be settings for performing transmission and / or reception in a target cell while continuing transmission and / or reception of user data in a source cell when performing an RRC connection reconfiguration including MobilityControlInfo in LTE or an RRC reconfiguration including a synchronization reconfiguration in NR, and may also be expressed by other names indicating equivalent settings. Further, "settings related to MBB-HO" may also be the case where, in LTE or NR, a specific information element (e.g., Figures 10 - 13 , Figure 21 the MakeBeforeBreak-r16 information element shown in and / or Figures 20 - 21 the mbb-drb shown in) is included in the RRC reconfiguration message. Further, "in the case of MBB-HO" and / or "being MBB-HO" may also be the case where the time (interruption time) during which data communication cannot be performed between the terminal device and the base station device is set to zero milliseconds (0 msec) or made close to zero milliseconds, and may also be expressed by other names indicating it.

[0809] In addition, in the above description, "make-before-break handover (MBB-HO)" may include a case where a master cell group for a target coexists with a master cell group for a source. In addition, "being MBB-HO" may be a case where, when performing an RRC connection reconfiguration including MobilityControlInfo in LTE or an RRC reconfiguration including a synchronization reconfiguration in NR, transmission and / or reception in a target cell is performed while continuing to perform transmission and / or reception of user data in a source cell, and it may also be expressed by another name indicating equivalent processing. In addition, "being MBB-HO" may be a case where, in LTE or NR, a specific first information element (e.g., Figures 10 - 13 , Figure 21 the MakeBeforeBreak-r16 information element shown therein) is included in a message related to the reconfiguration of an RRC connection. In addition, the radio bearer that performs transmission and / or reception in a target cell while continuing to perform transmission and / or reception of user data in a source cell as described above may be a radio bearer to which make-before-break handover is applied. The radio bearer to which the above-described make-before-break handover is applied may be a radio bearer indicated by a specific second information element (e.g., Figures 20 - 21 the mbb-drb shown therein).

[0810] In addition, in the above description, "make-before-break handover (MBB-HO)" may be a case where processing is performed to set the time (interruption time) during which data communication cannot be performed between a terminal device and a base station device to zero milliseconds (0 msec) or make it close to zero milliseconds (RUDI: Reduce User Data Interruption), and it may also be expressed by another name indicating it.

[0811] It should be noted that, in each embodiment of the present invention, handover may be renamed as Reconfiguration With Sync. For example, make-before-break handover may be renamed as make-before-break sync reconfiguration.

[0812] It should be noted that, in the above description, "A may be renamed as B" includes not only renaming A as B but also renaming B as A. In addition, in the above description, when "C may be D" and "C may be E" are described, it may include the case where "D may be E". In addition, in the above description, when "F may be G" and "G may be H" are described, it may include the case where "F may be H".

[0813] In addition, in the above description, when the condition of "A" and the condition of "B" are opposite conditions, the condition of "B" can be expressed as the "other" condition of the condition of "A".

[0814] Hereinafter, various aspects of the terminal device according to the embodiment of the present invention will be described.

[0815] (1) The first embodiment of the present invention is a terminal device that communicates with a base station device. When a first timer expires, based on a first setting for the terminal device, part or all of the settings of a target are released, the security key of a source is updated, the lower layer of part or all of the radio bearers in the source is set for integrity protection and encryption processing, the SRB1 of the source is restarted, and the base station device of the source is notified that the DAPS handover has failed.

[0816] (2) The second embodiment of the present invention is a method for a terminal device that communicates with a base station device. When a first timer expires, based on a first setting for the terminal device, part or all of the settings of a target are released, the security key of a source is updated, the lower layer of part or all of the radio bearers in the source is set for integrity protection and encryption processing, the SRB1 of the source is restarted, and the base station device of the source is notified that the DAPS handover has failed.

[0817] A program that operates in the device according to an aspect of the present invention can be a program that controls a Central Processing Unit (CPU: Central Processing Unit), etc., to implement the functions of the above-described embodiment according to an aspect of the present invention, so that a computer functions. The program or the information processed by the program is temporarily read into a volatile memory such as a Random Access Memory (RAM) or stored in a non-volatile memory such as a Flash Memory or a Hard Disk Drive (HDD) when being processed, and is read, modified, and written by the CPU as needed.

[0818] It should be noted that part of the device in the above-described embodiment can be implemented by a computer. In this case, a program for implementing the control function can be recorded on a computer-readable recording medium, and is implemented by reading the program recorded on the recording medium into a computer system and executing it. The "computer system" mentioned here refers to a computer system built into the device, and is assumed to include an operating system, peripherals, and other hardware. In addition, the "computer-readable recording medium" can be any of a semiconductor recording medium, an optical recording medium, a magnetic recording medium, etc.

[0819] Furthermore, the "computer-readable recording medium" may include: a medium that stores a program dynamically for a short period of time, such as a communication line in the case of transmitting a program via a network such as the Internet or a communication line such as a telephone line; and a medium that stores a program for a fixed period of time, such as a volatile memory inside a computer system of a server or a client in this case. In addition, the program may be a program for implementing a part of the functions described above, and may also be a program that can implement the functions described above through combination with a program already recorded in a computer system.

[0820] In addition, each functional block or each feature of the device used in the above-described embodiments can be implemented or executed by a circuit, typically by an integrated circuit or a plurality of integrated circuits. A circuit designed to perform the functions described in this specification may include: a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic elements, discrete gate or transistor logic, discrete hardware components, or a combination thereof. The general-purpose processor may be a microprocessor, or the processor may alternatively be an existing type of processor, a controller, a microcontroller, or a state machine. The general-purpose processor or each of the circuits described above may be composed of a digital circuit or an analog circuit. In addition, in the case where an integrated circuit technology that replaces existing integrated circuits appears with the progress of semiconductor technology, an integrated circuit based on this technology may also be used.

[0821] It should be noted that the invention of this application is not limited to the above-described embodiments. In the embodiments, an example of the device is described, but the invention of this application is not limited thereto, and can be applied to fixed or non-mobile electronic devices installed indoors and outdoors, such as terminal devices or communication devices such as AV devices, kitchen appliances, cleaning / washing appliances, air-conditioning appliances, office appliances, vending machines, and other household appliances.

[0822] As described above, the embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the specific configuration is not limited to this embodiment, and also includes design changes and the like within the scope not departing from the gist of the present invention. In addition, the present invention can be variously modified within the scope shown in the technical solutions, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. In addition, it also includes a configuration obtained by replacing elements having the same effect as the elements described in the above embodiments with each other.

[0823] One aspect of the present invention can be used, for example, in a communication system, communication devices (such as mobile phone devices, base station devices, wireless LAN devices, or sensor devices), integrated circuits (such as communication chips), or programs.

Claims

1. A terminal device that communicates with a base station device, the terminal device comprising: a receiving unit configured to receive, from the base station device, a radio resource control (RRC) reconfiguration message including parameters indicating a handover; and a processing unit, wherein, The processing unit is configured to: when the first timer expires, no radio link failure of the source primary cell is detected, and the dual active protocol stack (DAPS) is set for any radio bearer, reset the media access control (MAC) of the target primary cell, discard all data of the packet data convergence protocol (PDCP) entity of the signaling radio bearer (SRB) of the source primary cell, discard all data of the radio link control (RLC) entity of the SRB of the source primary cell, restart the SRB in the source primary cell, and send an RRC message to the base station device for notifying the case where the DAPS handover has failed, and The first timer is started when the terminal device receives the RRC reconfiguration message including the parameters indicating handover from the base station device, and stops when the random access to the specific cell (SpCell) is successful.

2. A method for a terminal device that communicates with a base station device, the method comprising: Receive a radio resource control (RRC) reconfiguration message including the parameters indicating handover from the base station device, when the first timer expires, no radio link failure of the source primary cell is detected, and the dual active protocol stack (DAPS) is set for any radio bearer, reset the media access control (MAC) of the target primary cell, discard all data of the packet data convergence protocol (PDCP) entity of the signaling radio bearer (SRB) of the source primary cell, discard all data of the radio link control (RLC) entity of the SRB of the source primary cell, restart the SRB in the source primary cell, and send an RRC message to the base station device for notifying the case where the DAPS handover has failed, and, The first timer is started when the terminal device receives the RRC reconfiguration message including the parameters indicating handover from the base station device, and stops when the random access to the specific cell (SpCell) is successful.

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