Radio base station and radio communication method

Abstract

When a terminal transitions between secondary nodes in accordance with mobility control performed by a lower layer, this radio base station receives connection information required for connection with a candidate secondary node from the candidate secondary node, and transmits the received connection information to the secondary node or terminal from which the transition originated.

Description

Radio base station and radio communication method

[0001] The present disclosure relates to a radio base station and a radio communication method that support L1 / L2 mobility.

[0002] The 3rd Generation Partnership Project (3GPP: registered trademark) is developing specifications for the 5th generation mobile communication system (5G, also known as New Radio (NR) or Next Generation (NG)), and is also developing specifications for the next generation, known as Beyond 5G, 5G Evolution, or 6G.

[0003] For example, 3GPP Release 18 discusses extensions to Layer 1 / Layer 2 mobility (L1 / L2 mobility). L1 / L2 mobility, also known as Lower Layer Triggered Mobility (LTM), is a technology related to the mobility of a terminal (User Equipment, UE) in Layer 1 or Layer 2, and includes the transition of a UE to another cell (handover (HO)) (Non-Patent Document 1). HO based on L1 / L2 mobility is realized by lower layers such as the Medium Access Control layer (MAC).

[0004] Furthermore, with regard to such LTM, it has been discussed that during dual connectivity (DC) in which communication is performed simultaneously between a UE and two NG-RAN nodes, a Timing Advance (TA) for adjusting the transmission timing of the uplink (UL), as well as information (connection information) on the TCI (Transmission Configuration Indication) state and active bandwidth portion (BWP) of the target cell should be provided to the UE (Non-Patent Document 1).

[0005] "Signalling approaches for LTM cell switch execution", R2-2308438, 3GPP TSG-RAN WG2 Meeting #123, 3GPP, August 2023

[0006] However, in the case of LTM between secondary nodes (SNs) (Inter-SN LTM), the current operation of LTM has a problem in that the SN cannot provide the connection information of the target cell (candidate cell) described above to the UE. In addition, in the case of Inter-SN LTM, there is also a problem in that early TA acquisition, which acquires TA early, cannot be performed.

[0007] For this reason, in the case of Inter-SN LTM, there is a concern that appropriate mobility control cannot be performed according to the conditions of candidate cells.

[0008] Therefore, the following disclosure has been made in consideration of such circumstances, and aims to provide a radio base station and a radio communication method that can realize appropriate mobility control according to the conditions of candidate cells, even in the case of Inter-SN LTM.

[0009] One aspect of the present disclosure is a radio base station (gNB100) that includes a receiver (handover processing unit 120) that receives connection information required for connecting to a candidate secondary node from a candidate secondary node when a terminal transitions between secondary nodes in accordance with mobility control by a lower layer, and a transmitter (handover processing unit 120) that transmits the received connection information to the secondary node from which the terminal transitions or to the terminal.

[0010] One aspect of the present disclosure is a terminal (UE200) that includes a receiver (handover execution unit 230) that receives a start instruction from a radio base station that explicitly or implicitly instructs the radio base station to start monitoring specific execution conditions used for mobility control by a lower layer, and a control unit (control unit 240) that starts monitoring the execution conditions based on the received start instruction.

[0011] FIG. 1 is a diagram showing an overall schematic configuration of a wireless communication system 10. FIG. 2 is a diagram showing an example of control using L1 / L2 mobility. FIG. 3 is a functional block configuration diagram of a gNB 100. FIG. 4 is a functional block configuration diagram of a UE 200. FIG. 5 is a diagram showing an example (example 1) of a communication sequence of Inter-SN LTM according to Operation Example 2. FIG. 6 is a diagram showing an example (example 2) of a communication sequence of Inter-SN LTM according to Operation Example 2. FIG. 7 is a diagram showing an example (example 1) of a communication sequence of UE-based LTM according to Operation Example 3. FIG. 8 is a diagram showing an example (example 2) of a communication sequence of UE-based LTM according to Operation Example 3. FIG. 9 is a diagram showing an example of the hardware configuration of a gNB 100 and a UE 200. FIG. 10 is a diagram showing an example of the configuration of a vehicle 2001.

[0012] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0013] (1) Overall Schematic Configuration of Wireless Communication System Fig. 1 is a diagram showing the overall schematic configuration of a wireless communication system 10 according to this embodiment. The wireless communication system 10 is a wireless communication system conforming to 5G New Radio (NR) and includes a Next Generation-Radio Access Network 20 (hereinafter, NG-RAN 20) and a terminal 200 (User Equipment 200, hereinafter, UE 200).

[0014] The wireless communication system 10 may be a wireless communication system conforming to a method called Beyond 5G, 5G Evolution, or 6G, or may include a wireless communication system conforming to a method called Long Term Evolution (LTE) or 4G. The wireless communication system 10 may support functions related to the Industrial Internet of Things (IIoT) and Ultra-Reliable and Low Latency Communications (URLLC).

[0015] The NG-RAN 20 includes a radio base station 100 (hereinafter, gNB 100). Note that the specific configuration of the radio communication system 10, including the number of gNBs (or eNBs, etc.) and UEs, is not limited to the example shown in FIG. 1 .

[0016] The gNB 100 may also employ a fronthaul (FH) interface defined by the Open Radio Access Network Alliance (O-RAN). The gNB 100 may include an O-RAN Distributed Unit (O-DU) and an O-RAN Radio Unit (O-RU). The gNB 100 can function as a type of NG-RAN node.

[0017] The NG-RAN 20 actually includes multiple NG-RAN nodes, specifically, gNBs (or ng-eNBs), and is connected to a 5G core network (5GC, not shown). The NG-RAN 20 and the 5GC may be simply referred to as a "network." The 5GC may introduce the concept of CUPS (Control and User Plane Separation), which clearly separates the functions of the user plane and the control plane.

[0018] The gNB100 is a radio base station conforming to NR and performs radio communication with the UE200 conforming to NR. The gNB100 may be configured to include a CU (Central Unit) and a DU (Distributed Unit), and the DU may be separated from the CU and installed in a different geographical location. One or more DUs may be connected to the CU. The gNB100 (gNB-CU) may be connected to each other via an Xn interface, and the CU and DU may be connected to each other via an F1 interface (such as an F1-AP).

[0019] The gNB100 and UE200 are capable of supporting Massive MIMO, which generates more directional beams by controlling radio signals transmitted from multiple antenna elements; Carrier Aggregation (CA), which aggregates and uses multiple component carriers (CCs); and Dual Connectivity (DC), which enables simultaneous communication between the UE and multiple NG-RAN nodes.

[0020] The type of DC may be Multi-RAT Dual Connectivity (MR-DC) that uses multiple radio access technologies, or NR-NR Dual Connectivity (NR-DC) that uses only NR. For example, one gNB may constitute a master node (MN), and one or more other gNBs may constitute secondary nodes (SNs).

[0021] In the wireless communication system 10, not only mobility control of the UE 200 at layer 3 (which may be referred to as L3 Mobility), but also mobility control at layer 1 and / or layer 2 (which may be referred to as L1 / L2 Mobility or LTM) may be applied. L3 Mobility may be interpreted as mobility control at the Radio Resource Control layer (RRC). On the other hand, L1 / L2 Mobility may be interpreted as mobility control at the physical layer (PHY), medium access control layer (MAC), radio link control layer (RLC), and packet data convergence protocol layer (PDCP) (mobility control by a lower layer).

[0022] In addition, in UE-based LTM, like conditional handover (CHO), the UE receives a specific execution condition from the radio base station (gNB), monitors the status according to the execution condition, and if the execution condition is satisfied, it may execute LTM.

[0023] In a broad sense, the mobility of UE200 may mean the ease of movement and maneuverability of UE200, but in this embodiment, it may also mean minimizing call drops, radio link (including beam) failures, unnecessary handovers, ping-pong states, etc.

[0024] Figure 2 shows an example of control by L1 / L2 mobility. As shown in Figure 2, MAC included in a lower layer (Layer 1 / Layer 2), rather than RRC included in Layer 3, can perform measurement reporting, handover (HO) decision from a source cell to a target cell (which may include a candidate), and management of a timer (herein referred to as T3xx for convenience) for determining whether HO is successful or not. T3xx may be interpreted as a timer set for the same purpose as timer T304 in L3, i.e., a timer used to determine whether HO (cell transition) is successful or not.

[0025] The MAC may report information about the measurement report, the HO decision, and the T3xx to a higher layer (RRC). The RRC may manage the state of radio resources accompanying the cell transition of the UE 200 based on the report.

[0026] In this embodiment, the channels include a control channel and a data channel, such as a physical downlink control channel (PDCCH), a physical uplink control channel (PUCCH), a physical random access channel (PRACH), and a physical broadcast channel (PBCH).

[0027] The data channels include a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH).

[0028] The reference signal includes a Demodulation Reference Signal (DMRS), a Sounding Reference Signal (SRS), a Phase Tracking Reference Signal (PTRS), and a Channel State Information-Reference Signal (CSI-RS), and the signal includes a channel and a reference signal. Furthermore, the data may refer to data transmitted via a data channel.

[0029] (2) Functional Block Configuration of Wireless Communication System Next, the functional block configuration of the wireless communication system 10 will be described. Specifically, the functional block configurations of the gNB 100 and the UE 200 will be described. Fig. 3 is a functional block configuration diagram of the gNB 100. Fig. 4 is a functional block configuration diagram of the UE 200.

[0030] (2.1) gNB100 As shown in FIG. 3, the gNB100 includes a radio communication unit 110, a handover processing unit 120, a measurement setting unit 130, and a control unit 140.

[0031] The wireless communication unit 110 transmits downlink signals (DL signals) conforming to NR, and also receives uplink signals (UL signals) conforming to NR.

[0032] The TCI state can provide information on antenna ports that are substantially co-located (quasi-collocated: QCL) with the antenna ports of the PDCCH. If the UE 200 has a specific control resource set (CORESET) that is spatially co-located with a specific CSI-RS, the UE 200 can determine which beam is appropriate when attempting to receive the PDCCH using the CORESET. Note that the QCL / TCI state / beam may be interchangeable.

[0033] The handover processing unit 120 executes handover of the UE 200. Specifically, the handover processing unit 120 executes handover of the UE 200 from a serving cell to another nearby cell.

[0034] The serving cell may be simply interpreted as a cell to which the UE 200 is connected, but more precisely, in the case of an RRC_CONNECTED UE in which carrier aggregation (CA) is not configured, there is only one serving cell that constitutes the primary cell. In the case of an RRC_CONNECTED UE configured using CA, the serving cell may be interpreted as indicating a set of one or more cells including the primary cell and all secondary cells.

[0035] The handover may also include a conditional handover (CHO) and / or a dual active protocol stack (DAPS) handover. CHO can execute a handover initiated by the UE 200 when a specific execution condition is met. If CHO is not applicable, a normal handover may be executed (which may be called CHO recovery). In CHO recovery, the UE 200 executes cell selection after a CHO failure. If a CHO candidate cell is selected, the UE 200 can directly apply conditional RRCReconfiguration of the selected cell to reconnect without transmitting an RRCRestablishmentRequest to the candidate target cell.

[0036] The execution condition may consist of one or two trigger conditions (CHO event A3 / A5 specified in 3GPP TS38.331). A single reference signal (RS) type may be triggered, and up to two different trigger quantities (e.g., Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ), RSRP and Signal-to-Interference plus Noise power Ratio (SINR)) may be simultaneously set for the evaluation of the CHO execution condition for a single candidate cell.

[0037] Furthermore, when the gNB 100 is a master node (MN) (same below) and the UE 200 transitions between secondary nodes in accordance with mobility control by a lower layer, specifically, L1 / L2 Mobility (LTM), the handover processing unit 120 can receive connection information required for connection with a candidate secondary node (SN) from the candidate secondary node. In this embodiment, the handover processing unit 120 may constitute a receiving unit that receives the connection information.

[0038] The handover processing unit 120 can also transmit the received connection information to the transition source secondary node or the UE 200. In this embodiment, the handover processing unit 120 may constitute a transmission unit that transmits the connection information.

[0039] A transition (handover) between candidate secondary nodes (which may also be read as target secondary nodes, target cells, or candidate cells) of a UE according to LTM may be referred to as Inter-SN LTM.

[0040] The connection information required for connecting to a candidate secondary node may be interpreted as information used by the UE 200 to connect to the candidate secondary node. For example, the connection information may include at least one of an uplink (UL) timing advance (TA), a TCI state (transmission configuration indication), and an active bandwidth portion (Active BWP) of the candidate secondary node.

[0041] The handover processing unit 120 may transmit the connection information to the UE 200 using a control element (CE) of a medium access control layer (MAC). Alternatively, the handover processing unit 120 may transmit the connection information to the UE 200 by a message of an upper layer (e.g., RRC). The handover processing unit 120 may also transmit the connection information to another SN or a master node (MN).

[0042] The handover processing unit 120 may receive the TA value from the candidate secondary node separately from the connection information, which may mean receiving the TA value earlier than the connection information.

[0043] Furthermore, the handover processing unit 120 may transmit to the UE 200 a start instruction that explicitly or implicitly instructs the UE 200 to start monitoring a specific execution condition used for L1 / L2 Mobility (LTM).

[0044] The measurement configuration unit 130 performs configuration (measurement configuration) of quality measurements of the serving cell and neighboring cells by the UE 200. Specifically, the measurement configuration unit 130 may perform measurement configuration in layer 3, or may perform measurement configuration in layer 1 and / or layer 2.

[0045] The measurement configuration unit 130 can notify the UE 200 of the contents of the measurement configuration. The UE 200 can measure the quality of the serving cell and / or neighboring cells based on the notified measurement configuration. The measurement configuration unit 130 can receive a measurement report from the UE 200 indicating the measurement result of the cell quality.

[0046] The control unit 140 controls each functional block constituting the gNB 100. In particular, in this embodiment, the control unit 140 can perform mobility control with the terminal. Specifically, the control unit 140 can perform not only mobility control according to L3 Mobility but also mobility control according to L1 / L2 Mobility (LTM).

[0047] In addition, the control unit 140 can perform control as a CU (source side or target side) or a DU (source side or target side) in a gNB100 having a CU-DU configuration.

[0048] (2.2) UE 200 As shown in FIG. 4, the UE 200 includes a radio communication unit 210, a measurement reporting unit 220, a handover execution unit 230, and a control unit 240.

[0049] The wireless communication unit 210 transmits an uplink signal (UL signal) conforming to NR. The wireless communication unit 210 also receives an uplink signal (DL signal) conforming to NR.

[0050] The measurement reporting unit 220 can measure the quality of the serving cell of the UE 200 and neighboring cells of the serving cell and report the measurement results (Measurement Report) to the network. The measurement reporting unit 220 can perform measurement reporting of the source cell and the target cell during handover.

[0051] The quality to be measured may be, for example, the quality included in the Measurement Report specified in 3GPP TS38.331 (e.g., Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ)).

[0052] The handover execution unit 230 executes handover of the UE 200. Specifically, the handover execution unit 230 may execute handover to a transfer destination cell (NG-RAN node) based on control by the gNB 100.

[0053] Furthermore, the handover execution unit 230 can execute processes related to normal handover (legacy handover), conditional handover (CHO), and DAPS handover.

[0054] In the case of CHO, the handover execution unit 230 may transition to the candidate cell when an execution condition is satisfied. As described above, the execution condition may be determined based on the quality of the reference signal (RS), specifically, the value of RSRP, RSRQ, or SINR.

[0055] In addition, the destination of the CHO may or may not be accompanied by an SCG. In other words, the destination cell of the CHO may be a single cell or may be composed of multiple cells (which may be read as a cell group) according to the DC.

[0056] Furthermore, the handover execution unit 230 may execute handover based on not only L3 mobility but also L1 / L2 mobility. Handover may be interpreted as transition, cell transition, cell selection, etc. Specifically, the handover execution unit 230 may execute handover based on L1 / L2 mobility based on at least one command of layer 1 and / or layer 2.

[0057] The type of the command is not particularly limited, but may be, for example, an L1 / L2 Mobility command. The L1 / L2 Mobility command may be replaced with another command of the RRC layer.

[0058] Furthermore, the handover execution unit 230 may receive a start instruction from the gNB 100, which explicitly or implicitly instructs the gNB 100 to start monitoring a specific execution condition used for L1 / L2 Mobility (LTM). In this embodiment, the handover execution unit 230 may constitute a receiving unit that receives the start instruction.

[0059] The handover execution unit 230 may receive setting information related to L1 / L2 Mobility (LTM). The setting information may mean settings related to LTM (LTM config). However, the setting information does not necessarily have to be LTM config as long as it indicates settings related to LTM (which may include execution conditions, etc.).

[0060] The control unit 240 controls each functional block constituting the UE 200. Specifically, the control unit 240 can execute control relating to the registration of the UE 200 to the network (standby in a specific cell), measurement reporting, and handover of the UE 200.

[0061] The control unit 240 can also perform L1 / L2 mobility, i.e., mobility control of at least one of layer 1 and layer 2. Mobility control using L1 / L2 mobility may include quality measurement of service areas and neighboring cells in layer 1 or layer 2, setting of destination candidate cells, cell reselection (transition), handover, etc.

[0062] In particular, in this embodiment, the control unit 240 may start monitoring the execution condition based on an instruction to start monitoring the execution condition received by the handover execution unit 230.

[0063] Furthermore, the control unit 240 may wait for a specific time (e.g., n seconds or n minutes) after the handover execution unit 230 receives the configuration information to receive connection information required for connecting to a candidate cell as a transfer destination. The connection information may refer to information used by the UE 200 to connect to a candidate secondary node, as described above.

[0064] When executing a random access procedure (RA procedure), the control unit 240 may start monitoring the execution condition. Conversely, when not executing an RA procedure, the control unit 240 may not start monitoring the execution condition and may wait for notification of the TA value in the candidate secondary node from the gNB 100.

[0065] (3) Operation of the Wireless Communication System Next, a description will be given of the operation of the wireless communication system 10. Specifically, a description will be given of the operation relating to handover between CU and DU using L1 / L2 Mobility (LTM).

[0066] (3.1) Assumptions As mentioned above, L1 / L2 Mobility (LTM) also supports dual connectivity, and it has been considered that the following information should be provided when Inter-SN LTM is executed. Specifically, it is considered that the serving DU needs to obtain the following dynamic information about the target cell to be included in the LTM cell switching command from the target (candidate) DU in advance.

[0067] (i) TA related information (ii) TCI state index of the target cell (iii) active BWP of the target cell

[0068] (3.2) Operation Example 1 In the Inter-SN LTM in dual connectivity, it is desirable that the above-described information (i) to (iii) be ultimately provided from the candidate SN to the UE. In addition, information related to a Contention Free RACH (CFRA) resource (e.g., a CFRA resource and / or an index indicating the CFRA resource) may be included in the information.

[0069] Therefore, in this operation example, in MN initiated inter-SN LTM or SN initiated inter-SN LTM, when the MN transmits an SgNB addition request message (see FIG. 5, etc.) or an SgNB modification request to the candidate target SN, the MN may request transmission of dynamic info (candidate cell ID, dedicated RACH resource (which may include a CFRA resource or an index indicating the CFRA resource), TCI state index(es) for the target cell, and active BWP for the target cell).

[0070] When returning an SN addition request acknowledge message or SgNB modification request Ack message to the MN, the Candidate Target SN may include information (candidate cell ID, dedicated RACH resource (which may include a CFRA resource or an index indicating a CFRA resource), TCI state index(es) for the target cell, active BWP for the target cell) upon request from the MN.

[0071] The MN may send dynamic information (candidate cell ID, TA value, TCI state index(es) for target cell, active BWP for target cell, CFRA resource or index indicating CFRA resource) to the UE using MAC CE (e.g., cell switch command MAC CE).

[0072] The information included in the dynamic info does not necessarily have to include all of the above-mentioned information elements, and only some of the information elements may be subject to transmission.

[0073] The MN may also transmit the dynamic information (candidate cell ID, TA value, TCI state index(es) for target cell, active BWP for target cell, CFRA resource or index indicating CFRA resource) to the source SN.

[0074] The source SN may send dynamic information (candidate cell ID, TA value, TCI state index(es) for target cell, active BWP for target cell, CFRA resource or index indicating CFRA resource) to the UE using MAC CE (e.g., cell switch command MAC CE).

[0075] According to this operation example, dynamic information (candidate cell ID, TA value, TCI state index(es) for target cell, active BWP for target cell, CFRA resource or index indicating CFRA resource) is provided to the source SN and UE, so that even in the case of Inter-SN LTM, appropriate mobility control can be achieved according to the status of the candidate cell, etc.

[0076] (3.3) Operation Example 2 In the case of Inter-SN LTM in dual connectivity, there is a problem that early TA acquisition, which allows early acquisition of a TA value, is difficult.

[0077] Therefore, in this operation example, an example of a communication sequence that can solve such a problem will be described. Fig. 5 shows an example of a communication sequence (example 1) of Inter-SN LTM according to operation example 2. Fig. 6 shows an example of a communication sequence (example 2) of Inter-SN LTM according to operation example 2.

[0078] (3.3.1) Example 1 As shown in Fig. 5, the UE may transmit an L1 measurement report to the MN. The MN may determine the cell(s) for which early TA acquisition is required from among candidate SN cells with good quality. The MN transmits a PDCCH order (candidate cell ID, SSB index, RACH preamble ID, RACH occasion) to the UE.

[0079] The UE transmits a PRACH to the candidate SN cell. The candidate SN may calculate a TA value and transmit the calculated TA value to the MN (see the underlined part in FIG. 5).

[0080] The MN may transmit the candidate cell ID and TA to the UE using a cell switch command MAC CE. The MN may also notify the candidate cell of LTM execution.

[0081] The UE may perform RACH-less LTM and send an RRCReconfigurationComplete to the MN.

[0082] (3.3.2) Example 2 As shown in Figure 6, the UE may send an L1 measurement report to the source SN. The source SN may determine the cell(s) for which early TA acquisition is required from among candidate SN cells with good quality. The source SN sends the PDCCH order (candidate cell ID, SSB index, RACH preamble ID, RACH occasion) to the UE.

[0083] The UE transmits a PRACH to the candidate SN cell. The candidate SN may calculate a TA value and transmit the calculated TA value to the MN (see the underlined part in FIG. 6). The MN may transmit the TA value to the source SN.

[0084] The Source SN may transmit the candidate cell ID and TA to the UE using a cell switch command MAC CE. The Source SN may also notify the MN of LTM execution, and the MN may notify the candidate SN of LTM execution.

[0085] The UE may perform RACH-less LTM and send an RRCReconfigurationComplete to the MN.

[0086] According to this operation example, the TA value of a candidate SN cell with good quality is provided to the UE, so that appropriate mobility control according to the status of the candidate cell can be achieved even in the case of Inter-SN LTM.

[0087] (3.4) Operation Example 3 As described above, in UE-based LTM, like Conditional HO, when a UE receives an execution condition from a gNB, it monitors the execution condition and executes LTM if the execution condition is satisfied.

[0088] In conventional Conditional HO, the UE starts monitoring the execution condition immediately after receiving it. However, in UE-based LTM, the network may provide the UE with dynamic information (e.g., TA, TCI state index for the target cell, active DL / UL BWP for the target cell). Therefore, if the UE starts monitoring the execution condition immediately, it may not be able to obtain information indicating the TA, TCI state index for the target cell, and active DL / UL BWP for the target cell.

[0089] Therefore, in this operation example, an example of a communication sequence that can solve such a problem will be described. Fig. 7 shows an example of a communication sequence (example 1) of UE based LTM according to operation example 3. Fig. 8 shows an example of a communication sequence (example 2) of UE based LTM according to operation example 3.

[0090] As shown in Figure 7 or 8, the gNB may send an indication to the UE indicating to start monitoring the execution condition, which may be done by L1 or L2 signaling or an RRC message (see Figure 7).

[0091] The indication may be explicit (e.g., a single bit may be used to indicate whether to start monitoring the execution condition or not). The UE may start monitoring the execution condition immediately after receiving the indication to start monitoring the execution condition.

[0092] Alternatively, the instruction may be implicit. The UE may implicitly start monitoring the execution condition after receiving a MAC CE including dynamic information (e.g., TA, TCI state index for the target cell, active DL / UL BWP for the target cell, CFRA resource, or CFRA resource index). The UE may not need to start monitoring the execution condition before receiving the dynamic information (see FIG. 8).

[0093] Alternatively, the UE may start a timer (which may be a new timer) after receiving the LTM config via an RRC message. While the timer is running, the UE may wait for reception of dynamic info (TA, TCI state index for the target cell, active DL / UL BWP for the target cell, CFRA resource, or index indicating the CFRA resource) from the gNB. While the timer is running, the UE does not need to start monitoring the execution condition. The UE may start monitoring the execution condition when the timer expires.

[0094] Alternatively, the gNB may send an instruction to the UE indicating that LTM will be performed via RACH or RACH-less. If RACH is to be performed, the UE may start monitoring the execution condition. Conversely, if RACH-less is to be performed, the UE may wait for notification of the TA value from the gNB. The UE may implicitly start monitoring the execution condition after receiving the TA value.

[0095] Alternatively, the UE may start monitoring the execution condition immediately after receiving the execution condition via the RRC message. While monitoring the execution condition (when the execution condition is not yet satisfied), the UE may wait for or receive dynamic info (TA, TCI state index for the target cell, active DL / UL BWP for the target cell, CFRA resource, or index indicating the CFRA resource) from the gNB.

[0096] The UE may perform LTM if the execution condition is satisfied and the UE does not have (receive) dynamic information (TA, TCI state index for the target cell, active DL / UL BWP for the target cell, CFRA resource, or index indicating the CFRA resource).

[0097] According to this operation example, an instruction to start monitoring the execution condition is sent explicitly or implicitly from the network, so that the UE can monitor the execution condition at the appropriate timing and perform UE-based LTM.

[0098] (4) Other Embodiments The contents of the present proposal have been explained above using examples, but it will be obvious to those skilled in the art that the present proposal is not limited to these descriptions and that various modifications and improvements are possible.

[0099] For example, in the above description, configure, activate, update, indicate, enable, specify, and select may be interchangeable. Similarly, link, associate, correspond, and map may be interchangeable, and allocate, assign, monitor, and map may be interchangeable.

[0100] Furthermore, specific, dedicated, UE-specific, and UE-dedicated may be interchangeable. Similarly, common, shared, group-common, UE-common, and UE-shared may be interchangeable.

[0101] The block diagrams (FIGS. 3 and 4) used to explain the above-described embodiments show functional blocks. These functional blocks (components) are realized by any combination of hardware and / or software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (e.g., wired, wireless, etc.) and these multiple devices. The functional block may also be realized by combining the single device or multiple devices with software.

[0102] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how each is implemented.

[0103] Furthermore, the above-described gNB100 and UE200 (the devices) may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 9 is a diagram showing an example of the hardware configuration of the devices. As shown in Figure 9, the devices may be configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0104] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the apparatus may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0105] Each functional block of the device (see FIGS. 3 and 4) is realized by any hardware element of the computer device or a combination of the hardware elements.

[0106] In addition, each function of the device is realized by loading specified software (programs) onto hardware such as processor 1001 and memory 1002, causing processor 1001 to perform calculations, control communication via communication device 1004, and control at least one of reading and writing data in memory 1002 and storage 1003.

[0107] The processor 1001 controls the entire computer by running, for example, an operating system, and may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control unit, an arithmetic unit, and registers.

[0108] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. Furthermore, the various processes described above may be executed by a single processor 1001, or may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0109] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 may store a program (program code), a software module, etc., capable of executing a method according to an embodiment of the present disclosure.

[0110] Storage 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned recording medium may be, for example, a database, a server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0111] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0112] The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize, for example, at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD).

[0113] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0114] Furthermore, each device such as the processor 1001 and the memory 1002 is connected to a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0115] Furthermore, the device may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0116] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0117] Each aspect / embodiment described in the present disclosure may be applied to at least one of a system using Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, a 4th generation mobile communication system (4G), a 5th generation mobile communication system (5G), a 6th generation mobile communication system (6G), an xth generation mobile communication system (xG) (where x is, for example, an integer or a decimal), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable system, and a next-generation system extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G) may also be applied.

[0118] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0119] In the present disclosure, a specific operation described as being performed by a base station may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal may be performed by at least one of the base station and another network node other than the base station (e.g., MME or S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, a combination of multiple other network nodes (e.g., MME and S-GW) may also be used.

[0120] Information, signals (information, etc.) may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input and output via multiple network nodes.

[0121] The input and output information may be stored in a specific location (for example, a memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added. The output information may be deleted. The input information may be transmitted to another device.

[0122] The determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0123] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0124] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0125] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0126] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0127] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0128] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0129] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, relative values ​​from a predetermined value, or other corresponding information. For example, a radio resource may be indicated by an index.

[0130] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0131] In this disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0132] A base station can accommodate one or more (e.g., three) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0133] The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0134] In the present disclosure, the base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control or operate based on the information.

[0135] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0136] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0137] At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, etc. The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0138] Furthermore, a base station in the present disclosure may be read as a mobile station (user terminal, the same applies hereinafter). For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a mobile station is replaced with communication between multiple mobile stations (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the mobile station may be configured to have the functions of a base station. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel (or sidelink).

[0139] Similarly, a mobile station in the present disclosure may be interpreted as a base station, in which case the base station may have the functions of a mobile station.

[0140] A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0141] Numerology may be communication parameters that apply to the transmission and / or reception of a signal or channel, such as subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0142] A slot may consist of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol, etc.) A slot may be a numerology-based time unit.

[0143] A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0144] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0145] For example, one subframe may be referred to as a transmission time interval (TTI), multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0146] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station schedules each user terminal to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) in TTI units. Note that the definition of TTI is not limited to this.

[0147] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0148] In addition, when one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling, and the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0149] A TTI having a time length of 1 ms may be referred to as a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be referred to as a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0150] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0151] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and may include one or more consecutive subcarriers in the frequency domain.

[0152] The number of subcarriers included in an RB may be the same regardless of the numerology, and may be, for example, 12. The number of subcarriers included in an RB may also be determined based on the numerology.

[0153] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI, each of which may consist of one or more resource blocks.

[0154] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0155] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0156] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0157] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0158] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0159] The above-described structures of the radio frame, subframe, slot, minislot, and symbol are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, and other configurations may be changed in various ways.

[0160] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0161] The reference signal may also be abbreviated as Reference Signal (RS) and may be called a pilot depending on the applicable standard.

[0162] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0163] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0164] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way.

[0165] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0166] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0167] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0168] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0169] 10 shows an example of the configuration of a vehicle 2001. As shown in Fig. 10, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013.

[0170] The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user. The electronic control unit 2010 is composed of a microprocessor 2031, memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals from various sensors 2021 to 2027 provided in the vehicle are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0171] The signals from the various sensors 2021 to 2028 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0172] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing (outputting) various types of information, such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 uses information acquired from external devices via the communication module 2013, etc., to provide various types of multimedia information and multimedia services to the occupants of the vehicle 1.

[0173] The information service unit 2012 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

[0174] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driver's driving burden, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS, etc.), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. The driving assistance system unit 2030 also transmits and receives various information via the communication module 2013 to realize driving assistance functions or autonomous driving functions.

[0175] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 1 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from a driving unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, a microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 2028, which are provided in the vehicle 2001.

[0176] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

[0177] The communication module 2013 may transmit at least one of signals from the above-mentioned various sensors 2021 to 2028 input to the electronic control unit 2010, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 2012 to an external device via wireless communication. The electronic control unit 2010, the various sensors 2021 to 2028, the information service unit 2012, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above-mentioned input.

[0178] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on an information service unit 2012 provided in the vehicle. The information service unit 2012 may also be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores the various information received from external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axles 2009, sensors 2021 to 2028, and the like provided in the vehicle 2001.

[0179] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0180] (Additional Note) The above disclosure may be expressed as follows: A first feature is a radio base station including: a receiver that, when a terminal transitions between secondary nodes in accordance with mobility control by a lower layer, receives connection information required for connection with a candidate secondary node from the candidate secondary node, and a transmitter that transmits the received connection information to a transition source secondary node or the terminal.

[0181] In a second feature based on the first feature, the connection information includes at least one of an uplink timing adjustment value, a transmission configuration indication, and an active bandwidth portion in the candidate secondary node.

[0182] A third feature based on the first or second feature is that the transmitter transmits the connection information to the terminal using a control element of a medium access control layer.

[0183] A fourth feature based on the first to third features is that the receiver receives the timing adjustment value from the candidate secondary node separately from the connection information.

[0184] According to a fifth feature in any one of the first to fourth features, the transmission unit transmits, to the candidate secondary node, information indicating that the terminal will transition to the candidate secondary node.

[0185] A sixth feature is a terminal that includes a receiving unit that receives, from a radio base station, a start instruction that explicitly or implicitly instructs the terminal to start monitoring specific execution conditions used for mobility control by a lower layer, and a control unit that starts monitoring the execution conditions based on the received start instruction.

[0186] A seventh feature is the sixth feature, wherein the receiving unit receives configuration information related to the mobility control, and the control unit waits for reception of connection information required for connecting to a candidate cell as a transition destination at a specific time after receiving the configuration information.

[0187] An eighth feature based on the sixth or seventh feature is that, when executing a random access procedure, the control unit starts monitoring the execution condition.

[0188] 10 Wireless communication system 20 NG-RAN 100 gNB 110 Wireless communication unit 120 Handover processing unit 130 Measurement setting unit 140 Control unit 200 UE 210 Wireless communication unit 220 Measurement reporting unit 230 Handover execution unit 240 Control unit 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Left and right front wheels 2008 Left and right rear wheels 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 RPM sensor 2023 Air pressure sensor 2024 Vehicle speed sensor 2025 Acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object detection sensor 2029 Accelerator pedal sensor 2030 Driving assistance system section 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port

Claims

1. A radio base station comprising: a receiving unit that receives, from a candidate secondary node, connection information required for connecting to a candidate secondary node when a terminal transitions between secondary nodes in accordance with mobility control by a lower layer; and a transmitting unit that transmits the received connection information to the secondary node from which the terminal transitions or to the terminal.

2. The radio base station of claim 1, wherein the connection information includes at least one of an uplink timing adjustment value, a transmission configuration indication, and an active bandwidth portion for the candidate secondary node.

3. The radio base station according to claim 1, wherein the transmission unit transmits the connection information to the terminal using a control element of a medium access control layer.

4. The radio base station according to claim 2, wherein the receiver receives the timing adjustment value from the candidate secondary node separately from the connection information.

5. The radio base station according to claim 4, wherein the transmitting unit transmits, to the candidate secondary node, information indicating that the terminal will transition to the candidate secondary node.

6. A wireless communication method in a master node, comprising: when a terminal transitions between secondary nodes in accordance with mobility control by a lower layer, a step of receiving connection information required for connecting to a candidate secondary node from the candidate secondary node; and a step of transmitting the received connection information to the secondary node from which the terminal transitions or to the terminal.

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